U.S. patent application number 11/297420 was filed with the patent office on 2006-04-27 for resin roller and device and method for manufacturing the resin roller.
This patent application is currently assigned to KANEKA CORPORATION. Invention is credited to Kenji Kobayashi, Toshiyuki Komatsu, Hiroshi Ohgoshi, Koji Sezaki, Hidenari Tsunemi.
Application Number | 20060088623 11/297420 |
Document ID | / |
Family ID | 27552912 |
Filed Date | 2006-04-27 |
United States Patent
Application |
20060088623 |
Kind Code |
A1 |
Ohgoshi; Hiroshi ; et
al. |
April 27, 2006 |
Resin roller and device and method for manufacturing the resin
roller
Abstract
A resin roller (10) is produced by disposing a core body (21) in
a forming metal mold (1) having a cylindrical metal mold (13) and
core supporting members (14) furnished at both edge parts of the
cylindrical metal mold (13) as well as causing the core supporting
members (14) to hold said both edge parts, and pouring a farming
resin into the metal mold and solidifying it. The resin roller (10)
has the core body (21) of the same outer diameter over a full
length and a cylindrical resin-formed body (12), sealing members
(24, 26) are furnished around the core body (21) in the vicinity of
both edge parts of the resin-formed body (12), and the core body
(21) is disposed such that the sealing members (24, 26) contact
edge faces (14a) at sides of a roller forming space of the core
supporting members (14).
Inventors: |
Ohgoshi; Hiroshi; (Shiga,
JP) ; Komatsu; Toshiyuki; (Tokyo, JP) ;
Sezaki; Koji; (Tokyo, JP) ; Tsunemi; Hidenari;
(Shiga, JP) ; Kobayashi; Kenji; (Shiga,
JP) |
Correspondence
Address: |
WESTERMAN, HATTORI, DANIELS & ADRIAN, LLP
1250 CONNECTICUT AVENUE, NW
SUITE 700
WASHINGTON
DC
20036
US
|
Assignee: |
KANEKA CORPORATION
Osaka-shi
JP
|
Family ID: |
27552912 |
Appl. No.: |
11/297420 |
Filed: |
December 9, 2005 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
11098673 |
Apr 5, 2005 |
|
|
|
11297420 |
Dec 9, 2005 |
|
|
|
09926562 |
Feb 5, 2002 |
6915570 |
|
|
PCT/JP00/03168 |
May 17, 2000 |
|
|
|
11098673 |
Apr 5, 2005 |
|
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Current U.S.
Class: |
425/543 |
Current CPC
Class: |
B29K 2995/0005 20130101;
G03G 2215/0861 20130101; G03G 15/2053 20130101; B29C 45/14418
20130101; G03G 15/0818 20130101; B29L 2031/324 20130101; B29C
45/0001 20130101; B29K 2105/0023 20130101; B29C 45/14549 20130101;
Y10T 29/49563 20150115; B29K 2083/005 20130101; G03G 15/1685
20130101; G03G 15/0233 20130101; Y10T 29/49984 20150115; G03G
2215/0863 20130101 |
Class at
Publication: |
425/543 |
International
Class: |
B29C 45/38 20060101
B29C045/38 |
Foreign Application Data
Date |
Code |
Application Number |
May 19, 1999 |
JP |
P.HEI.11-139253 |
May 19, 1999 |
JP |
P.HEI.11-139254 |
Jun 4, 1999 |
JP |
P.HEI.11-157267 |
Jun 4, 1999 |
JP |
P.HEI.11-157340 |
Jun 4, 1999 |
JP |
P.HEI.11-157360 |
Aug 18, 1999 |
JP |
P.HEI.11-231370 |
Claims
1. A roller producing apparatus using a thermosetting liquid resin,
producing a roller which is composed of a core body and a
resin-made elastic layer covering around the core body by use of a
metal mold having a structure disposed with core supporting members
holding a roller forming space therebetween at both ends of a
cylindrical metal mold inserted inside with the core body,
characterized in that the core supporting member is provided with a
mold-inner pressure adjusting mechanism.
2. The roller producing apparatus using a thermosetting liquid
resin as set forth in claim 1, wherein the mold-inner pressure
adjusting mechanism provided in the core supporting member is
equipped with a volume-variable spare room communicating with the
roller forming space.
3. The roller producing apparatus as set forth in claim 2, wherein
when an inner diameter of the cylindrical metal mold is D, an outer
diameter of the roller is d, and an outer diameter is ds, the inner
diameter D of the cylindrical metal mold, the outer diameter d of
the roller, and the outer diameter ds are prescribed such that a
value of cross sectional shrinkage factor .alpha. defined with
(D2-d2)/(D2-ds2) is 0.02 to 0.06, and the thickness of the elastic
layer expressed with (d-ds)/2 is 1 mm or more.
Description
[0001] This application is a divisional of application Ser. No.
11/098,673, filed Apr. 5, 2005, which is a divisional of
application Ser. No. 09/926,562, filed Feb. 5, 2002, now U.S. Pat.
No. 6,915,570, which is a .sctn.371 of International application
no. PCT/JP00/03168, filed May 17, 2000.
TECHNICAL FIELD
[0002] The present invention relates to a resin roller such as a
film developing roller, an electrically charging roller, or a
transcribing roller to be incorporated into various kinds of
devices employing an electrophotographic system of a laser printer,
copier or facsimile apparatus. Further, the present invention
relates to an apparatus of producing the resin roller. Still
further, the invention relates to an injection molding apparatus of
the resin roller as well as a forming metal mold.
TECHNICAL BACKGROUND
[0003] Many kinds of devices employing electrophotographic systems
of a laser printer, copier or facsimile apparatus are incorporated
with a roller such as a film developing roller, an electrically
charging roller, or a transcribing roller. One example of these
rollers is shown in FIG. 24.
[0004] A roller 10 has a core body 21 and a cylindrical forming
body 12 fabricated with a resin. A metal mold for forming the
roller 10 has, as shown in for example FIG. 25, a cylindrical metal
mold 13 and core supporting members 14 located at upper and lower
both edges of the cylindrical metal mold 13 for supporting a core
21 inserted inside of the cylindrical metal mold 13 and sealing
both edges of the cylindrical metal mold 13. The lower core
supporting member 14 is defined with a resin injecting inlet 16 for
injecting a resin material into a roller forming space 15, while
the resin injecting inlet 16 is urged outside of the metal mold
with a resin injecting nozzle 18 of a forming machine from a
semi-circular nozzle touch portion 19, so that the resin material
is introduced into the roller forming 15.
[0005] After completion of filling the resin into the metal mold,
the resin in the roller forming space 15 is hot-set. Hot-setting
the resin, the core supporting members 14 are removed upward and
downward respectively along an axial direction from the cylindrical
metal mold 13. Subsequently, the core body 21 is extruded from the
cylindrical metal mold 13 to take out a formed product (roller)
held within the cylindrical metal mold 13.
[0006] The core supporting member 14 is provided with concave parts
17 for supporting the core body 21 at edges 21a, and in order to
make easy insertion of the edge 21a of the core supporting member
14 into the concave part 17 or taking variation within dimensional
tolerance of the edge of the core body into consideration, spaces
of 10 to 20.mu. are provided between the concave part 17 and the
core supporting member 14. So, if the resin is poured into the
metal mold at high pressure or if a pressure in the mold is high
when the resin is expanded at hot-setting, a defect is present that
the resin leaks out of the metal mold from the spaces. The leaked
resin is adhered to the edges 21a of the core body 21 or to an
interior of the concave part 17 of the core supporting member 14,
and it should be removed after formed products have been released
from the mold.
[0007] In case the core body 21 used to the resin roller is, as
shown in FIG. 25, differs an outer diameter in the center part of
the core body 21 and an outer diameter in the edge part 21a of the
core body 21, and the outer diameter in the center part of the core
body 21 is larger than that of the edge part, a method is to attach
sealing members 24 (for example, O-ring) to the core supporting
member 14 so as to contact side faces of the center part of the
core body 21 for preventing the resin leakage.
[0008] However, the core body 21 being different in the outer
diameters in the center part and in the center part thereof has
disadvantages of high processing cost and high material cost of the
core body 21, and accordingly a cost of the core body 21 is
expensive.
[0009] In order to lower the cost of the core body 21 and make
thickness of an elastic layer large for aiming at reducing rubber
elastic hardness of the formed body 12 (elastic layer), such a core
body 21 is sometimes used which uses core body 21 being the same in
the center part of the core body 21 and the outer diameter in the
edge part 21a of the core body 21.
[0010] In this case, as illustrated in FIG. 26, used is the core
supporting member 14 which is buried with sealing members 24 (for
example, O-ring) opening in the concave part 17 thereof. But there
is a defect that the sealing members 24 buried in the core
supporting member 14 are broken while repeatedly attaching the core
body 21 to the concave parts 17, so that an effect for avoiding the
resin leakage is decreased.
[0011] Further, for adopting a structure of burying the sealing
members in the core supporting member 14, taking strength of
burying grooves into consideration, it is necessary to bury the
sealing members in depth of around 0.5 to 1 mm from the side edge
face of a resin formed product of the core supporting member 14.
Therefore, until around 0.5 to 1 mm from the side edge face of the
resin formed product of the core supporting member 14, the resin
leakage cannot be stopped with the sealing members 24, and the
resin leakage 30 by the amount thereof occurs.
[0012] When using the core body 21 which is the same in the outer
diameter in the center part of the core body 21 and the outer
diameter in the edge part 21a thereof, a problem is to shorten a
life of the sealing member and cause the resin leakage in parts
from a resin formed edge part to the sealing member.
[0013] Thus, it is indispensable to frequently exchange the sealing
members owing to the short life thereof and remove the leakage
resin at edge parts, and in turn a cost-up of the resin roller is
invited.
[0014] Next, reference will be made to using methods of the roller
by use of an example of the resin roller for a photographic film
developing process, referring to FIG. 27.
[0015] In various kinds of devices of the electrophotographic
system, there is a system known as a photographic film developing
process for visualizing electrostatic latent images, which supplies
a nonmagnetic unary developer 55 on an image carrier 51 of a
photosensitive body 50 of carrying the electrostatic latent image,
adhering said developer to the electrostatic latent image on the
surface of the image carrier, and contacting a developing resin
roller 10a to the image carrier 51.
[0016] Using the nonmagnetic unary developer 55, this system is
cheap in comparison with a system supplying the magnetic developer
by use of the conventional magnetic roller. In a case of using a
magnetic binary developer, a carrier itself has a short life, for
example, it must be periodically exchanged per 10000 or 20000
copies, taking trouble for exchanging the carrier. On the other
hand, the above mentioned system does not have such a defect.
Further, in a case of using the magnetic binary developer, since
the magnetic developer itself contains a magnetic substance near a
different color, it is technically difficult to make the magnetic
developer a color toner, but since the resin roller of the
invention is employed to the nonmagnetic developing system using
the nonmagnetic developer, such a problem is absent.
[0017] Typical shapes of the resin roller are shown in FIGS. 28, 29
and 30. The resin roller 10a has a core body 21, a cylindrical
resin layer 12a formed with a resin around the core body 21, and a
surface layer 12b covering the periphery of the resin layer
12a.
[0018] A method for the resin roller 10a to send the nonmagnetic
unary developer, depends on an electrically absorbing force, and
since a property necessary as the developing roller makes the
developer frictional electrification between the developing surface
and a regulating blade 52 for regulating a piling thickness of the
developer on the surface of the developing roller, the developer is
easily cracked owing to pressurization, and such a developing
roller 10a is served which covers a soft resin layer 12a on the
core body 21 for avoiding the developer from cracking.
[0019] The resin layer 12a is often exposed at the surface, but for
controlling electric charging of the developer or transferring
performance, it is provided on the surface with a thin surface
layer 12b.
[0020] Further, explanation will be made to a producing method of
the resin roller 10a.
[0021] At first, a metal mold 120 for forming the resin layer 12a
of the resin roller 10a has, as shown in for example FIG. 31, a
cylindrical metal mold 13 and the core supporting members 14, 14
located at upper and lower both edges of the cylindrical metal mold
13 for supporting a core 21 inserted inside of the cylindrical
metal mold 13 and sealing both edges of the cylindrical metal mold
13. The lower core supporting member 14 is defined with a resin
injecting inlet 16 for injecting a resin material into a roller
forming space 15 formed within the cylindrical metal mold 13, while
the resin injecting inlet 16 is urged outside of the metal mold
with a resin injecting nozzle 18 of a forming machine from a
semi-circular nozzle touch portion 19, so that the resin material
is introduced into the roller forming space 15.
[0022] After completion of filling the resin into the metal mold
120, the whole of the mold 120 is heated to hot-set the resin in
the roller forming space 15. Hot-setting the resin, the core
supporting members 14, 14 are removed upward and downward
respectively along the axial direction from the cylindrical metal
mold 13. Subsequently, the core body 21 is extruded from the
cylindrical metal mold 13 to take out a formed product (roller) 10b
held within the cylindrical metal mold 13.
[0023] After that, the resin layer 12a of the roller main body 10b
produced by the above forming method is coated on the peripheral
surface thereof with a treated liquid mixed with a resin material
through a spray method, a dipping method or a roll coater method,
and dried to form a surface layer 12b.
[0024] The roller main body 10b produced by the above forming
method has swelling parts at edge parts of the resin layer 12a as
shown in FIG. 32 when releasing from the metal mold. A mechanism of
the swelling phenomenon at the edge is explained that the swelling
is generated by thermal expansion and shrinkage owing to
temperature difference between temperatures at pouring the resin
into the metal mold 120 and after releasing from the mold, the
amount of shrinkage in the axial direction is larger than that in
the peripheral direction, and the formed resin is adhered to the
core body 21. Even if the swelling part at the edge part of the
resin layer 12a is cut in round slice in the peripheral direction,
the edge part after cutting apparently swells similarly.
[0025] The cylindrical metal mold 13 and the core supporting
members 14, 14 have tolerances of respective parts and assembling
spaces, and so-called parting lines occur. If the spaces become
large owing to such as abrasion in the respective parts when
setting up the metal mold, the resin flows into the spaces and
burrs are created at the edges of the resin layer 12a as shown in
FIG. 33.
[0026] The corner 74 of the resin roller 10a is obtained by forming
the surface layer 12b around the resin layer 12a of the resin
roller 10a in the above mentioned method, and as shown in FIG. 34,
actually the film thickness of a resin forming the surface layer
12b is small.
[0027] When the resin roller 10a contacts and slides with the image
carrier as the sensitive substance, since the corner of the resin
roller 10a contacts the periphery of the image carrier at larger
force than that exerting in the center part of the resin roller 10a
and the film thickness of the surface layer 13b is smaller than
that in the center part, the surface layer 12b of the corner of the
resin roller 10a is easily worn, and in turn this abrasion causes
the surface layer 12b to peel off, and as a time passes, the
surface layer 12b gradually widens to peel in the surface of the
resin roller 10a.
[0028] For resolving those occasions, there is a method of
uniformly machining or polishing the surface of the resin roller
prior to coating the surface layer, but it takes many processing
steps, and besides the resin layer is soft, and in particular the
corner could not be precisely machined or polished.
[0029] Another method is to machine or polish the only corner, but
some of elastic resins such as, above all, silicone forming the
resin layer have viscosity or stickiness particular to these
resins, so that processing parts are nappy or ragged, and the
surface cannot be processed to be smooth. There is another
available method which carries out the process of immersing or
coating water or oil to the processing part of the resin roller
while machining or polishing, but after processing, it is further
necessary to remove water or oil.
[0030] Next, an apparatus of producing the roller will be explained
in detail. The apparatus of producing the roller is mainly
structured with, as shown in FIG. 35, for example, a cylindrical
metal mold 61 and the core supporting members 62a, 62a located at
upper and lower both edges of the cylindrical metal mold 61 for
supporting a core 21 inserted inside of the cylindrical metal mold
61 and sealing both edges of the cylindrical metal mold 61.
[0031] The lower core supporting member 62b is defined with a
straight resin injecting inlet 64 for injecting the resin material
into a roller forming space 63 formed within the cylindrical metal
mold, while the resin injecting inlet is provided on the way with a
closure mechanism 68 for regulating a resin fluid. If a resin
injecting nozzle (not shown) at the side of the forming machine is
urged to a nozzle touch portion 65 formed to be semi-circular with
a part opening toward outside of the metal mold of a resin
injecting inlet 64, so that the resin material is introduced into
the roller forming space 63.
[0032] On the other hand, the upper core supporting member 62a is
defined with a straight air vent hole 66, and a closure mechanism
67 is provided as crossing with the air vent hole 66 for closing
the resin fluid.
[0033] The summary of the method of forming the roller by use of
this producing apparatus is as follows.
[0034] At first, the core body 21 inserted within the cylindrical
metal mold 61 is held at its upper and lower edges by the upper and
lower core supporting members 62a, 62b, and subsequently a
hot-setting liquid resin is filled into the roller forming space 63
through the resin injecting inlet 64, and on completion of filling,
the closure mechanism 68 in the lower core supporting member 62b is
operated to check a counter flow of the resin expanding within the
cylindrical metal mold when hot-setting.
[0035] In contrast, the air vent hole 66 provided in the upper core
supporting member 62a releases the closure mechanism 67 during
filling the resin to exhaust the air in the roller forming space
via the air vent hole 66 outside of the metal mold, and on
completion of filling the resin, the closure mechanism is closed,
and under this condition, the resin staying in the roller forming
space is hot-set.
[0036] On completion of hardening the resin, the core supporting
members 62a, 62b are removed upward and downward from the
cylindrical metal mold 61 along the axial direction, and finally a
formed product held within the cylindrical metal mold 61 is taken
out by extruding the core body 21 with respect to the cylindrical
metal mold 61. This is a method of producing rollers by means of
this kind of the conventional apparatus.
[0037] However, the conventional roller producing apparatus and
method are involved with many problems.
[0038] For example, in the conventional roller producing method, a
metal mold device composed of the core supporting member and the
cylindrical metal mold is charged with a thermosetting resin, and
then the upper and lower closure mechanisms are closed to make the
forming space a closed space. The closed space is filled with the
thermosetting resin to form an elastic layer (formed body), and at
this time the resin hot-set within the closed metal mold is
generated with cubical expansion. Since the filled thermosetting
liquid resin is non-compressive, an internal pressure within the
metal mold by the cubic expanded resin is considerably high. A
magnification of this internal pressure is normally more than 100
kg/cm.sup.2, though depending on air tightness of the closure
mechanism provided in the core supporting member, and so the metal
mold must have sufficient pressure resistant strength. Accordingly,
thickness of the cylindrical metal mold is large, and load should
be large for connecting the cylindrical metal mold and the core
supporting member.
[0039] If the internal pressure within the metal mold is large, the
resin flows into the parting line between the cylindrical metal
mold and core supporting member, and this becomes a burr appearing
at the roller peripheral part, so that a secondary process as a
polishing is necessary to remove burrs. Further, the resin often
leaks from the closure mechanism 68 provided in the lower core
supporting member 62b, so that a work is demanded to remove the
resin adhered to the metal mold after having formed to cause the
working efficiency to go down.
[0040] A problem is present when taking out the formed product from
the metal mold. If the internal pressure within the metal mold is
large, as the surface of the elastic layer is closely adhered to
the inner surface of the metal mold, when releasing from the mold
after completion of hardening, resistance against releasing from
the mold is still large even if the elastic layer is shrunk with
enough cooling time, and scratches often appear on the surface of
the elastic layer by releasing from the mold. For avoiding these
occasions, the cylindrical metal mold is carried out with a
fluorine coating treatment, or a plating treatment for heightening
smoothness, but with such only measures, the mold releasing
property is not yet sufficient, and actually a mold releasing agent
is coated on the inside of the metal mold per each time.
[0041] Next, referring to FIG. 36, explanation will be made to
another conventional method of making rollers using the
thermosetting liquid resin. This method comprises mixing
silicone-based liquid base polymer (main agent), a cross linking
agent, a catalyst and if necessary an electrically conductive agent
within a vacuum agitating-defoaming device, rendering this to be
one liquid state, storing it in a container 81, subsequently
transferring a thermosetting liquid resin 82 in the container 81 by
use of a force feed pump 83 to an injection device 84, sending to a
cylinder 86, measuring a predetermined amount, and injecting into a
cavity of a roller forming metal mold 88 via an injecting nozzle
87, thereby to form a roller main body. Herein, a cooling device 90
is necessary to normally keep cooled at about 10.degree. C. or
lower the transferring course comprising the container 81,
injecting device 84, injecting nozzle 87 and transferring tube 89.
In the illustrated example, a cooling liquid is circulated and
supplied from the cooling device 90 through pipes 91a, 91b, 91c,
91d so as to cool each of the parts. The cooling device is provided
because if this is absent, a bridging reaction of the thermosetting
liquid resin progresses, and the liquid resin is adhered to and
solidified on the inner walls of the transferring course comprising
the container 81, injecting device 84 and transferring tube 89, and
obstacles transferring of the liquid resin, so that the apparatus
is frequently necessarily disassembled to clean to remarkably
decrease productivity.
[0042] Since this cooling system heightens production cost, there
is an attempt of adding a hardening retard agent to the liquid
resin for avoiding the cost-up, and lengthening a pot life, but as
a progressing risk of the bridging reaction of the liquid resin
staying in the container 81 is high, a problem occurs in variation
of quality between rollers at a beginning period of and after the
injection forming.
[0043] However, in the conventional roller producing method
employing the above mentioned cooling system,
[0044] (1) since the thermosetting liquid resin is cooled down at
about 10.degree. C. or lower and increases viscosity, an injecting
pressure is heightened to fill it into the cavity, it is necessary
to design the thickness of the roller forming metal mold to be
durable against the injecting pressure, and
(2) if injecting the once cooled liquid resin, a problem arises
that a heating load is increased when hot-setting, and a hardening
reaction time is extended.
[0045] FIG. 37 is a schematically cross sectional view showing
another example of the conventional injection forming apparatus
(metal mold). In the same, reference numeral 41 designates the
cylindrical metal mold, 42 shows the core body inserted inside of
the cylindrical metal mold 41, 43, 44 are the core supporting
members, 45, 46 are cover members screwed inside with thread, and
47 is a pin. A sequence of forming the elastic roller by use of the
injection forming metal mold is as follows. At first, the
cylindrical metal mold 41 is inserted with the core body 42, both
edge parts 42a, 42b thereof are fitted in core supporting holes
43a, 44a provided in the cylindrical metal molds 43, 44, these core
supporting members 43, 44 are engaged in the cylindrical metal mold
41, subsequently screwing cover members 45, 46 on the cylindrical
metal mold 41 to protect them and to form the roller forming space
48 for closing the injection forming metal mold.
[0046] Next, an attaching hole 49 defined in the cover member 46 is
attached with the resin injecting nozzle (not shown), the resin
material is injected and filled into the roller forming space 48
through the resin injecting inlet 44b penetrating the core
supporting member 44, an attaching hole 150 penetrating the cover
member 45 is closed with a pin 47 to shut a vent hole 151, and the
cylindrical metal mold 41 is heated to hot-set the resin material.
Herein, as the heating means, listed are means contacting a heating
mechanism (not shown) to an outside surface of the cylindrical
metal mold 41, or means moving the injection forming metal mold
into a blast furnace (not shown) to heat it.
[0047] After hot-setting, the cylindrical metal mold 41 is cooled,
and the metal mold is opened in a sequence reversal to the above
mentioned for releasing the formed product from the mold, and by
repeating the above mentioned sequence, a new formed product is
made.
[0048] However, the forming apparatus having the conventional
injection forming metal mold as mentioned above has the following
problems. One of them is difficult to automatize the steps of
fitting the core supporting members 43, 44 in the cylindrical metal
mold 41 and mounting the cover members 45, 46 by screwing in the
production process, and must depend on manual operation. For
example, when screwing the cover members 45, 46 on the cylindrical
metal mold 41, if a tightening load is too large, the core body 42
receives excessive load and is easily bent, and if it is too small,
the resin material leaks out owing to pressure of the filled resin
to generate burrs in a formed product, resulting in decreasing the
formability of the roller. Therefore, the tightening load should be
adjusted, but automatization of this adjustment is difficult, not
depending on the manual operation, and even if the automatization
of this kind of steps is possible, since facility investment of the
automatized mechanism is very expensive, so that it cannot cope
with recent fierce low cost competitions. In particular, in case of
mass production using the production apparatus of a plurality of
rollers, this problem is remarkable and very much labor is
demanded.
[0049] In addition, since the prior forming apparatus has such a
complicated structure of the metal mold, when getting rid of the
adhered and solidified resin after hot-setting, a maintenance
working for dissolving and cleaning the roller producing apparatus
is troublesome, taking much labor and inviting cost-up.
[0050] However, as shown in FIG. 38, when taking out the formed
product from the cylindrical metal mold 13 upward or downward along
the axial direction, owing to friction between an outer periphery
12e of a resin formed product 12 and an inside 13a of the
cylindrical metal mold 13, force is exerted in the axial direction
between an outer periphery 21e of the core body 21 and an inside
periphery 12f of the resin-formed body 12, and when the formed body
is extracted from the cylindrical metal mold 13, a relative
position between the core body 21 and the resin-formed body 12
often gets out of position. In particular, force is concentrated to
a part X of an edge 12c of the resin-formed body 12 and the core
body 21 contacting, and as seen in FIG. 38B, the edge of the
resin-formed body 12 and the core body 21 separate, and this
portion serves as a trigger to often develop to a whole separation
of the resin-formed body 12 and the core body 21. Therefore, a
further method is to coat the cylindrical metal mold 13 on the
inside with a mold releasing agent for reducing friction between
the outer periphery 12e of the resin-formed body of the product and
the inside 13a of the cylindrical metal mold, thereby lowering the
shifting force exerting in the axial direction between the outer
periphery 21e and the inner periphery 12f of the resin-formed body
contacting the same. This method increases a step of coating the
mold releasing agent, resulting in cost-up.
[0051] Silicone based addition type liquid rubber material enabling
to be liquid-injected inherently ordinarily used as the resin
material for forming the elastic layer; polyether based addition
type liquid rubber material which hydrosilyl-hardens terminal
allylated polyoxyalkylene based polymer or terminal allylated
polyolefin based polymer with poly siloxane based hardening agent;
polyolefin based addition type liquid rubber material; urethane
based liquid rubber material; EPDM rubber enabling to be
injection-formed; millable silicone rubber; or NBR rubber are low
in density of polar group contributing to the adhesion or scarcely
contain the polar group, thereby to be difficult to adhere a metal
made core body. Also in a case of using primer for improving the
adhesion of the resin-formed body 12 to the core body 21, depending
on the coating of primer to the metal core body 21, influences of
adhesion checking substance (for example, a cutting oil) remaining
on the metal core body or variation in histories of temperature and
moisture after drying, differences arise in a film forming property
of the primer component or the adhesion thereof with metal, or
residual degree of functional group, so that the adhesion between
the resin-formed body 12 and the metal core body 21 might vary. If
an injection pressure is high in the metal mold during forming, the
primer on the surface of the metal core 21 is forced out by the
resin flowing and the primer does not fully display effect, and
even if the primer is coated, a sufficiently satisfied adhesion
cannot be obtained. Besides, of course a step of coating the primer
is added to invite cost-up.
[0052] Thus, when taking out the formed product from the
cylindrical metal mold 13 upward or downward along the axial
direction, owing to friction between an outer periphery 12e of a
resin formed product 12 and an inside 13a of the cylindrical metal
mold 13, force is exerted in the axial direction between an outer
periphery 21e of the core body 21 and an inside periphery 12f of
the resin-formed body 12, and a relative position between the core
body 21 and the resin-formed body 12 often gets out of position.
There is a method of in advance coating the primer to the core 21
for heightening the adhesive strength between the core 21 and the
resin-formed body 12, but this method is involved with problems of
increasing a primer coating step and that the liquid rubber
material used as a resin forming material is inherently weak in the
adhesive force with the metal core 21. Therefore, by decrease in
the rate of good products by getting out of a relative position
between the core 21 and the resin-formed body 12 or addition of the
primer coating step, the cost-up is caused in the production of
resin rollers.
[0053] Accordingly, it is an object of the invention to offer a
resin roller enabling to check resin leakage from a formed roller,
though using a core body having the same outer diameter in the edge
portion as a center part thereof.
[0054] It is another object of the invention to offer a resin
roller improving durability in a surface layer and in turn having a
long life.
[0055] It is a further object of the invention to offer a roller
producing apparatus which is easy to release from a mold, obtains
rollers without scratches or burrs, enables to use a metal mold
having a structure of thin thickness and light weight and to
shorten a cooling time before releasing the mold, and a method
thereof.
[0056] It is a still further object of the invention to offer a
roller producing apparatus which does not employ a cooling step of
a liquid resin being a technical common knowledge in the prior art,
restrains heating load and shortens a hardening reaction time for
decreasing energy loss, is excellent in productivity and less to
vary product quality, and a method thereof.
[0057] It is a yet further object of the invention to offer an
apparatus of injection-forming rollers which largely reduces
manually operating steps, easily accomplishes automatization of
opening and closing the metal mold, lighten maintenance work, and
enables to make rollers at low cost.
[0058] It is another object of the invention to offer a resin
roller which enables to prevent peeling in a part contacting the
edge faces of the resin-formed body and the core body for checking
getting out of a relative position between the resin-formed body
and the core body in the formed resin roller, and a forming metal
mold therefor.
DISCLOSURE OF THE INVENTION
[0059] The resin roller of the invention is produced by disposing a
core body in a forming metal mold having a cylindrical metal mold
and core supporting members furnished at both edge parts of the
cylindrical metal mold as well as causing the core supporting
members to hold said both edge parts, and pouring a forming resin
into the metal mold and solidifying it, and is characterized in
that the resin roller has the core body of the same outer diameter
over a full length and a cylindrical resin formed body, sealing
members are furnished around the core body in the vicinity of both
edge parts of the resin-formed body, and the core body is disposed
such that the sealing members contact edge faces at sides of a
roller forming space.
[0060] In another embodiment, the core body is defined with grooves
for attaching E-rings and when the E-ring is attached in the groove
and the core body is disposed in the metal mold, the sealing
members are provided to the core body such that the sealing members
respectively contact the E-ring and the edge faces of the core
supporting members.
[0061] In another embodiment, the cylindrical member is attached to
the core body and when the core body is disposed in the metal mold,
the sealing members are provided to the core body such that the
sealing members respectively contact the cylindrical metal mold and
the core supporting members.
[0062] In another embodiment, the sealing members are provided to
the core body and when the core body is disposed within the metal
mold, the edge faces of the sealing members contact the edge faces
of the core supporting members.
[0063] In another embodiment, the core body is defined with grooves
for attaching the sealing members, and when the core body is
disposed within the metal mold, the sealing members are disposed
such that the sealing members contact the edge faces of the core
supporting members in the grooves.
[0064] In another embodiment of the invention, the resin roller has
the core body of the same outer diameter over a full length and a
cylindrical resin-formed body provided at the center part of the
core body, and is characterized in that the sealing members are
disposed around the core body in the vicinity of both edges of the
resin-formed body, and edge faces of the sealing members are the
same as edge faces of the resin-formed body or project.
[0065] A method of producing the resin roller according to the
invention comprises the step of disposing the core supporting
members at both edge parts of the cylindrical metal mold and
holding the core body with both core supporting members, and the
step of pouring the forming resin into the roller forming space
formed between the cylindrical metal mold and the core supporting
members and solidifying the forming resin to form a resin-formed
body around the core body, and is characterized by disposing the
sealing members around the core body in the vicinity of the edge
parts of the resin-formed body, elastically contacting the sealing
members to the sides of the roller forming space of the core
supporting members, and, under this condition, pouring the forming
resin into the roller forming space.
[0066] By the way, in case a measure against the resin leakage for
the core supporting members and the core body is required to both
edges of the core body, the same sealing method is not necessarily
selected.
[0067] Further, the resin roller according to the invention is
characterized in that the resin roller is formed in the roller main
body by providing a cylindrical resin layer around the core body,
and the roller main body is chamfered or rounded at corners of edge
parts of the resin layer, and the resin layer is formed on the
surface with a surface layer.
[0068] In an embodiment, the hardness of the resin layer is
25.degree. or lower (JIS-A).
[0069] In another embodiment, a dimension of the part for
chamfering or rounding the corner of the resin layer is 1 to 40
times of a swelling amount of the edge part having a larger
diameter than the center part of the formed roller main body.
[0070] A method of producing the resin roller according to the
invention is characterized by comprising the step of disposing the
core body in the forming metal mold, pouring the thermosetting
liquid resin into the metal mold for hot-setting, and forming the
roller main body furnished with a cylindrical resin layer around
the core body, the step of releasing the roller main body from the
metal mold, followed by chamfering or rounding the corners of the
edge parts of the resin layer, and the step of forming the surface
layer around the resin layer.
[0071] In an embodiment, the step of chamfering or rounding the
corners of the edge parts of the resin layer comprises a step of
heating the corners to fuse and remove the resin at the
corners.
[0072] In another embodiment, the step of chamfering or rounding
the corners of the edge parts of the resin layer comprises a step
of coating a solvent to the corner for dissolving and removing the
resin at the corner.
[0073] In another embodiment, the hardness of the resin layer is
25.degree. or lower (JIS-A).
[0074] In another embodiment, when the swelling amount of the edge
part in comparison with that of the center part of the formed
roller body is 1, the swelling amount of the part for chamfering or
rounding is 1 to 40 times of said swelling amount in the diameter
direction as well as the axial direction.
[0075] In another embodiment, the thermosetting liquid resin
contains, as main components, (A) polymer containing at least one
alkenyl group in molecule and a repeating unit composing a main
chain being mainly oxy alkylene unit or saturated hydrocarbon unit,
(B) a hardening agent containing at least two hydrosilyl group in
molecule, (C) catalyst made hydrosilyl, and (D) conductivity giving
agent.
[0076] Further, the roller producing apparatus of the invention is
to produce a roller composed of the core body and a resin-made
elastic layer covering around the core body by use of a metal mold
having a structure disposed with the core supporting members
holding the roller forming space therebetween at both ends of the
cylindrical metal mold inserted inside with the core body, and is
characterized in that the core supporting member is provided with a
mold inner pressure adjusting mechanism.
[0077] In an embodiment, the mold inner pressure adjusting
mechanism provided in the core supporting member is equipped with a
volume-variable spare room communicating with the roller forming
space.
[0078] In another embodiment, an inner diameter D of the
cylindrical metal mold, an outer diameter d of the roller, an outer
diameter ds and thickness of the elastic layer are prescribed such
that a value of cross sectional shrinkage factor .alpha. defined
with (D2-d2)/(D2-ds2) is 0.02 to 0.06, and the thickness of the
elastic layer expressed with (d-ds)/2 is 1 mm or more.
[0079] In another embodiment, for forming the resin roller, the
core supporting member is provided with a mold inner pressure
adjusting mechanism, and a mold inner pressure during hot-setting
is adjusted to be 100 kg/cm.sup.2 or lower.
[0080] A further method of the invention is to produce a roller for
an electrophotographic apparatus composed of a main body formed
with a curing type liquid resin and support shafts for supporting
both edges of the main body, and is characterized by preparing a
roller forming metal mold provided with a space for forming a
roller main body as well as provided with a resin injecting inlet
for filling a hardening type liquid resin in the roller forming
space, storing separately a hardening type liquid resin containing
a cross linking agent and another hardening type liquid resin
containing a catalyst, respectively measuring to be set amounts
thereof, and as mixing both hardening liquid resins, injecting a
mixture into the forming space from the resin pouring inlet so as
to effect a hardening reaction for forming the roller main
body.
[0081] The roller producing apparatus depending on such a method is
characterized by providing a roller forming metal mold formed with
a space for forming a roller main body as well as provided with a
resin injecting inlet for filling the hardening type liquid resin
in the roller forming space, containers for storing separately a
hardening type liquid resin containing a bridging agent and another
hardening type liquid resin containing a catalyst, an injecting
device furnished with measuring mechanisms for respectively
measuring both resins to be set amounts, and a mixing mechanism for
mixing both measured liquid resins, injecting, as mixing both
resins, a mixture into the forming space from the resin pouring
inlet so as to effect a hardening reaction for forming the roller
main body.
[0082] In an embodiment, a temperature adjusting instrument is
provided, and it is preferable to adjust temperature of the
hardening type liquid resin at injecting to be within a range of 20
to 70.degree. C., and to adjust viscosity of the hardening type
liquid resin at injecting to be 5000 poise.
[0083] When controlling the electric conductivity of the roller, it
is desirable to add the conductivity giving agent of the same
amount to the hardening type liquid resin containing the bridging
agent and the other hardening type liquid resin containing the
catalyst
[0084] It is preferable that the composition of the hardening type
liquid resin has polymer containing at least one alkenyl group in
molecule and a repeating unit composing a main chain being mainly
oxy alkylene unit or saturated hydrocarbon unit, and the bridging
agent has at least two hydrosilyl group in molecule.
[0085] An apparatus of injection-forming roller of the invention is
characterized by having a cylindrical metal mold inserted inside
with the core body and core supporting members detachably fitted to
both edge parts in the axial direction of the cylindrical metal
mold as holding both edges of the inside inserted core body, and is
composed by disposing heating mechanisms for hot-setting the resin
material introduced in a roller forming space around the injection
forming metal mold having the roller forming space, said core
supporting member having a 1st obliquity tilting at a fixed angle
with respect to an axial and vertical direction in the outer wall
face, and said heating mechanism having an inner wall face
contacting to hold the injection forming metal mold under a
condition of closing the heating mechanism and having a 2nd
obliquity pressing the 1st obliquity to the inner wall face,
whereby the injection forming metal mold is tightened and held.
[0086] More specifically, it is preferable that the core supporting
member has a 1st obliquity at the outer periphery, while the
heating mechanism has pawl members with the 2nd obliquity pressing
the 1st obliquity to the inner wall face under the condition of
closing the heating mechanism.
[0087] Another specific structure is preferable in that a brim part
having the 1st obliquity is expanded at an outer periphery of the
fitting position of the core supporting member and the cylindrical
metal mold, and the brim part is engaged with the inner wall face
of the heating mechanism under the condition of closing the heating
mechanism, while the groove with the 2nd obliquity pressing the 1st
obliquity is formed in concave shape.
[0088] Preferably, a heat resistant elastic member such as rubber
is interposed between the 1st obliquity and 2nd obliquity, and
desirably the tilt angle of the 1st obliquity is set in a range of
5 to 30.degree..
[0089] Further, a resin roller of the invention is formed with a
cylindrical resin-formed body around the core body, and is
characterized in that the resin-formed body is formed as standing
along the core body toward the edge of the core body.
[0090] The resin roller is produced by disposing the core body in
the forming metal mold having a cylindrical metal mold and core
supporting members furnished at both edge parts of the cylindrical
metal mold as well as causing the core supporting members to hold
said both edge parts, and pouring the resin into the metal mold and
solidifying it.
[0091] In an embodiment, the standing state of the resin-formed
body reduces a diameter in arc toward the edge of the core
body.
[0092] In another embodiment, the standing state of the
resin-formed body reduces a diameter linearly toward the edge of
the core body.
[0093] In another embodiment, the standing state of the
resin-formed body reduces a diameter stepwise toward the edge of
the core body.
[0094] Incidentally, in the inventive resin roller, it is not
necessary that the resin-formed body is formed as standing at both
edge parts. If either one of the edges is formed to stand, it is
sufficient to form one of the edges positioning forward to stand
when extracting a formed product from the metal mold. Besides, if
both edges are formed to stand, it is not necessary to form both
edges in the same shape.
[0095] The inventive resin roller forming metal mold holds the
cylindrical metal mold and the core body furnished at both edge
parts of the cylindrical metal mold and inserted inside of the
cylindrical metal mold, and is characterized in that a ring shaped
concave groove is formed at an opening edge of a core holding hole
provided in the core supporting member, said groove being larger in
diameter than an outer diameter of the core body to be inserted in
said core holding hole.
[0096] In an embodiment of the resin roller forming metal mold, the
ring shaped concave groove reduces the diameter as advancing an
inner part of the core holding hole.
BRIEF DESCRIPTION OF THE DRAWINGS
[0097] FIG. 1 is a cross sectional view showing a forming metal
mold of the resin roll in an embodiment of the invention;
[0098] FIG. 2 is a cross sectional view showing the forming metal
mold of the resin roll in another embodiment of the invention;
[0099] FIG. 3 is a cross sectional view showing the forming metal
mold of the resin roll in a further embodiment of the
invention;
[0100] FIG. 4 is cross sectional views showing the relation between
the forming metal mold and attaching positions of the sealing
members;
[0101] FIG. 5 is a cross sectional view showing the forming metal
mold of the resin roll in a still further embodiment of the
invention;
[0102] FIG. 6 is cross sectional views showing the core bodies and
the resin rollers used in the invention;
[0103] FIG. 7 is a view showing one example of chamfering swelling
corners in edge parts of the resin layer in a yet still
embodiment;
[0104] FIG. 8 is cross sectional views of the resin layer and the
surface layer in this embodiment;
[0105] FIG. 9 is a cross sectional view showing an apparatus of
producing the roller in another embodiment;
[0106] FIG. 10 is an enlarged cross sectional view of an inner
pressure adjusting mechanism of this embodiment;
[0107] FIG. 11 is a schematic view showing a structure of the
apparatus for explaining the method of producing the roller
according to the invention;
[0108] FIG. 12 is schematic views showing the apparatus of
injection forming the roller of another embodiment according to the
invention, in which A is a plan view of this apparatus and B is a
bottom view thereof;
[0109] FIG. 13 is a schematically cross sectional view showing the
side view of the apparatus of injection forming the roller of this
embodiment;
[0110] FIG. 14 is enlarged cross sectional views of elementary
parts of the apparatus of injection forming the roller of this
embodiment;
[0111] FIG. 15 is a schematically cross sectional view showing a
modified example of this embodiment;
[0112] FIG. 16 is schematic views showing the apparatus of
injection forming the roller of another embodiment according to the
invention, in which A is a plan view of this apparatus and B is a
bottom view thereof;
[0113] FIG. 17 is a schematically cross sectional view showing the
side view of the apparatus of injection forming the roller of this
embodiment;
[0114] FIG. 18 is enlarged cross sectional views of elementary
parts of the apparatus of injection forming the roller of this
embodiment;
[0115] FIG. 19 shows another embodiment, in which A is a vertically
cross sectional view of the forming metal mold and B is a cross
sectional view of an elementary part showing a standing state in
the resin roller to be formed by the metal mold;
[0116] FIG. 20 shows another embodiment, in which A is a vertically
cross sectional view of the forming metal mold and B is a cross
sectional view of an elementary part showing a standing state in
the resin roller to be formed by the metal mold;
[0117] FIG. 21 is a further embodiment, in which A is a vertically
cross sectional view of the forming metal mold and B is a cross
sectional view of an elementary part showing a standing state in
the resin roller to be formed by the metal mold;
[0118] FIGS. 22A to 22C are cross sectional views of the resin
rollers showing examples of the core bodies to be employed to the
invention;
[0119] FIGS. 23A to 23G are cross sectional views showing examples
of the standing states at edge faces of the formed bodies in the
resin rollers of the invention;
[0120] FIG. 24 is a perspective view of an ordinary resin
roller;
[0121] FIG. 25 is a cross sectional view showing a state of resin
injecting in the core body and the forming metal mold in the prior
art;
[0122] FIG. 26 is a cross sectional views showing states of resin
injecting in the core body and the forming metal mold in the prior
art;
[0123] FIG. 27 is a cross sectional view of elementary parts of the
electrophotographic apparatus;
[0124] FIG. 28 is a perspective view of a conventional resin
roller;
[0125] FIG. 29 is a cross sectional view of a conventional resin
roller;
[0126] FIG. 30 is a cross sectional view of a conventional resin
roller;
[0127] FIG. 31 is a cross sectional view showing a resin pouring
state into a forming metal mold;
[0128] FIG. 32 is a cross sectional view of one example of a roller
main body formed by the forming metal mold;
[0129] FIG. 33 is a cross sectional view of another example of a
roller main body formed by the forming metal mold;
[0130] FIG. 34 is a cross sectional view of edge corners of a resin
layer and the surface layer of the prior art;
[0131] FIG. 35 is a cross sectional view showing the prior art
roller producing apparatus;
[0132] FIG. 36 is a schematic view showing the apparatus structure
for explaining the prior art roller producing apparatus;
[0133] FIG. 37 is a schematically cross sectional view showing
another example of the conventional injection forming apparatus;
and
[0134] FIG. 38 is cross sectional views showing separating states
of the resin body and the core when releasing the formed body from
the mold in the resin roller formed body and the forming metal mold
in the prior art.
MOST PREFERRED EMBODIMENT OF THE INVENTION
Embodiment 1
[0135] The resin roller of the invention will be explained with
reference to the attached drawings.
[0136] As shown in FIG. 1, the forming metal mold 1 has the
cylindrical metal mold 13 and a pair of core supporting members 14,
14 disposed at both ends of the cylindrical metal mold 13, and the
cylindrical metal mold 13 and the pair of core supporting members
14 define the roller forming space 15. One of the core supporting
members 14 is provided with the resin injecting inlet 16.
[0137] The core body 21 has the same outer diameter over a
lengthwise direction, and is located at ends 21a in concave parts
17 formed in the core supporting members 14. After forming, a
cylindrical formed body 12 is produced which is composed of resin
at the center part of the core body 21.
[0138] Shapes of the core body 21 are pertinent to those shown in
FIGS. 6A to 6C, and for the core body 21 of the resin roller, known
optional materials, for example, metal materials or conductive
resin materials are applicable as the core body 21 of the
invention.
[0139] By the way, the core body 21 shown in FIG. 6A is a bar like
material having the same outer diameter, the core body 21 shown in
FIG. 6B is formed at both ends with engaging parts 31 for attaching
to a machine, and the core body 21 shown in FIG. 6C is formed at
one end with an engaging part 31 of plural steps.
[0140] As to optional dimensions of known resin rollers, the
forming metal mold, the core body 21 and the sealing members are
applicable, and generally, a diameter is 10 to 30 mm and a length
is 200 to 400 mm.
[0141] The cylindrical metal mold 13 and the core supporting member
14 are composed of known arbitrary materials for thermosetting
liquid resin, preferably pre-hardened steel, quenched steel,
non-magnetic steel, carbon tool steel, or corrosion resistant steel
(stainless steel).
[0142] The core supporting members 14 have steps 20 for holding
cylindrical metal mold 13 at the periphery thereof and the concave
parts 17 at the center parts thereof, and the pair of core
supporting members 14, 14 are located in opposition to both ends of
the cylindrical metal mold 13, while the cylindrical metal mold 13
is fitted at both ends to steps 20 of the core supporting members
14. Thus, the forming metal mold 1 is composed. The core body 21 is
inserted at its ends in the concave parts 17 formed in the core
supporting members 14, and is disposed in the forming metal mold
1.
[0143] As shown in FIG. 1, the core body 21 is provided with
grooves 23 for holding E-rings 22, and the sealing members 24 are
furnished to contact the E-rings 22 held in the grooves 23 and
contact edge faces 14a of the roller forming space 15 of the core
supporting members 14.
[0144] As to positions for providing the E-rings 22 and the sealing
members 24, as illustrated in FIG. 4, if a distance L2 between ends
of the sealing member s 24 at both edges is made larger than a
distance L1 between ends of the pair of core supporting members 14,
14 under a condition of setting up the forming metal mold 1, so
that the sealing members 24 are compression-deformed owing to
pressure when incorporating the core supporting members 14 to the
cylindrical metal mold 13, this manner is more preferable for
increasing the sealing effect.
[0145] As to the quality of the sealing member, available are resin
materials as polyethylene, polypropylene, polyamide, polycarbonate
or polyimide, such resin materials of said resin materials rendered
to be conductive as needed, or metal materials as aluminum, brass,
iron, and of course such materials should be selected which are not
fused and deformed when hot-setting after pouring.
[0146] Especially, as materials effective against compressive
deformation by the setting force of the core supporting member 14
and the resin leakage, available are elastic resin materials as
polyvinylchloride, silicone, polyurethane, EPDM or NBR, such resin
materials of said resin materials rendered to be conductive as
needed, or metal materials as copper, brass or phosphor bronze.
[0147] The sealing member 24 is manufactured by injecting formation
or extruding formation, punching process of a sheet or plate,
forging or casting, and shapes have preferably inner diameters
closing to the core body 21, thickness of 0.1 to 3 mm and length of
0.1 to 20 mm, more preferably thickness being 0.1 to 2 mm and
length being 1 to 5 mm. Cross sectional shapes are circular,
semi-circular, oval or square.
[0148] The above materials are made sheets, and if necessary, a
tape coated with an adhesive on the rear side is wound on the sheet
to make a sealing member 24. Otherwise, if a thermal shrinkage tube
produced with a thermally shrinking resin material is applied to
the core body 21, and heated and shrunk, it can be attached to a
desired position.
[0149] Using mass-produced O-rings, the sealing members 24 are
cheaply got and further cost-down is possible. For example, using
O-rings on the market, if the outer diameter of the core body 21 is
5 to 10 mm, a diameter in cross section of the O-ring is ordinarily
1.9 mm, and if the distance L2 between the ends of the pair of
sealing members 24 is determined such that the O-ring is compressed
by 0.5 mm by the setting force of the core supporting member 14, a
result is more preferable.
Embodiment 2
[0150] FIG. 2 shows another embodiment.
[0151] The core body 21 is attached with cylindrical members 25,
and the sealing members 24 are furnished on the core body 21 so as
to contact the cylindrical member 25 and contact edge faces 14a at
the side of the roller forming space of the core supporting member
14. The cylindrical member 25 is attached to the core body 21 by
manners as adhesion, caulking, urging insertion by force-fitting
dimension, or inserting formation into the core body 21. In either
way, such manners are adopted which are not easily moved by
vibration or expansion pressure when forming a formed body 12.
[0152] As to the quality of the cylindrical member 25, available
are resin materials as polyethylene, polyproplylene, polyamide,
polycarbonate or polyimide, such resin materials of said resin
materials rendered to be conductive as needed, or metal materials
as aluminum, brass, iron, copper or phosphor bronze, and of course
such materials should be selected which are not fused and deformed
when hot-setting after pouring.
[0153] In particular, for urging to insert the cylindrical member
to the core body 21, making use of elasticity of the resin, useful
are elastic resin materials as polyvinylchloride, silicone,
polyurethane, EPDM or NBR, such resin materials of said resin
materials rendered to be given conductive as needed.
[0154] The above materials are made sheets, and if necessary, a
tape coated with an adhesive on the rear side is wound on the sheet
to make a sealing member 24. Otherwise, if a thermal shrinkage tube
produced with a thermally shrinking resin material is applied to
the core body 21, and heated and shrunk, it can be attached to a
desired position.
[0155] The dimensions of the cylindrical member are preferably
thickness of 0.5 to 3 mm and length of 2 to 20 mm, more preferably
thickness being 0.5 to 2 mm and length being 2 to 10 mm.
[0156] Also as to the attaching position of the cylindrical member
25 and the sealing member 24, as above mentioned, if the distance
L2 between ends of the sealing members 24 at both edges is made
larger than the distance L1 between ends of the pair of core
supporting members 14 under the condition of setting up the forming
metal mold, so that the sealing member s 24 are
compression-deformed owing to pressure when incorporating the core
supporting members 14 to the cylindrical metal mold 13, this manner
is more preferable for increasing the sealing effect.
[0157] The quality, dimensions and shapes are the same as those of
the above mentioned embodiment.
Embodiment 3
[0158] FIG. 3 shows another embodiment.
[0159] Cylindrical sealing members 26 are attached so as to contact
to the edge faces 14a at the side of roller forming space of the
core supporting members 14 with respect to the core body 21 by
manners as adhesion, caulking, or urging insertion by force-fitting
dimension, or inserting formation into the core body 21.
Especially, in a case of elastic resin materials as synthetic
rubbers to be elastically deformed by tension, it is effective to
select those of smaller inner diameter than that of the core body
21. In either way, such manners are of course adopted which are not
easily moved by vibration or expansion pressure when forming a
formed body 12.
[0160] As to the attaching position of the cylindrical sealing
member 26, if the distance L2 between ends of the cylindrical
sealing members 26 at both edges is made larger than the distance
L1 between ends of the pair of core supporting members 14 under the
condition of setting up the forming metal mold, so that the sealing
members 24 are compression-deformed owing to pressure when
incorporating the core supporting members 14 to the cylindrical
metal mold 13, this manner is more preferable for increasing the
sealing effect.
[0161] As to the quality of the cylindrical sealing member 26,
available are resin materials as polyethylene, polypropylene,
polyamide, polycarbonate or polyimide, such resin materials of said
resin materials rendered to be conductive as needed, or metal
materials as aluminum, brass or iron, and of course such materials
should be selected which are not fused and deformed when
hot-setting after pouring.
[0162] Especially, if expecting such materials effective against
compressive deformation by the setting force of the core supporting
member 14 and the resin leakage, available are elastic resin
materials as polyvinylchloride, silicone, polyurethane, EPDM or
NBR, such resin materials of said resin materials rendered to be
conductive as needed, or metal materials as copper, brass or
phosphor bronze.
[0163] The sealing member 26 is manufactured by injecting formation
or extruding formation, punching process of a sheet or plate,
forging or casting, and shapes have preferably inner diameters
closing to the core body 21, thickness of 0.01 to 3 mm and length
of 0.5 to 20 mm, more preferably thickness being 0.01 to 2 mm and
length being 1 to 5 mm. Cross sectional shapes are circular,
semi-circular, oval or square.
[0164] The above materials are made sheets, and if necessary, a
tape coated with an adhesive on the rear side is wound on the sheet
to make a sealing member 26. Otherwise, if a thermal shrinkage tube
produced with a thermally shrinking resin material is applied to
the core body 21, and heated and shrunk, it can be attached to a
desired position.
Embodiment 4
[0165] FIG. 5 shows another embodiment.
[0166] The core body 21 is defined with grooves 27 for attaching
the sealing members 24, and the sealing members 24 are attached so
as to contact the edge faces 14a of the core supporting members 14.
As to the attaching position of the sealing member 24, if the
distance L2 between ends of the sealing member s 24 at both edges
is made larger than the distance L1 between ends of the pair of
core supporting members 14 under the condition of setting up the
forming metal mold, so that the sealing members 24 are
compression-deformed owing to pressure when incorporating the core
supporting members 14 to the cylindrical metal mold 13, this manner
is more preferable for increasing the sealing effect.
[0167] The dimensions of the sealing member 24 are determined such
that a part of the sealing member 24 projects outside of the outer
periphery of the core body 21 from the groove when the sealing
member 24 is attached into the groove 27.
[0168] As to the quality of the sealing member 24, available are
resin materials as polyethylene, polyproplylene, polyamide,
polycarbonate or polyimide, such resin materials of said resin
materials rendered to be conductive as needed, or metal materials
as aluminum, brass or iron, and of course such materials should be
selected which are not fused and deformed when hot-setting after
pouring. Especially, as such materials effective against
compressive deformation by the setting force of the core supporting
member 14 and the resin leakage, available are elastic resin
materials as polyvinylchloride, silicone, polyurethane, EPDM or
NBR, such resin materials of said resin materials rendered to be
conductive as needed, or metal materials as copper, brass or
phosphor bronze. If mass produced O-rings are used, the sealing
members are cheaply available to cost down.
[0169] The sealing member 24 is manufactured by injecting formation
or extruding formation, punching process of a sheet or plate,
forging or casting, and shapes have inner diameters closing to the
groove 27 of the sealing member, and the outer diameter has
preferably a dimension largely protruding 10 to 90% of the
thickness of the sealing member from the outer peripheral face. The
thickness is preferably 0.1 to 5 mm, the length is 0.1 to 20 mm and
the thickness is 1 to 3 mm, more preferably the thickness is 1 to 3
mm and the length is 1 to 5 mm. Cross sectional shapes are
circular, semi-circular, oval or square.
[0170] The depth of the groove 27 for holding the sealing member 24
to the core body 21 is preferably 10 to 90% of the thickness of the
sealing member 24.
[0171] Next, explanation will be made to the method of producing
the resin roller of the invention by use of the core body 21 and
the structure of the outer periphery of the same.
[0172] Polysiloxane based hardening agent and the conductivity
giving agent (carbon black) are mixed in terminal allylated
polyoxypropylene based polymer, and when forming a roller of an
outer diameter being .phi.16 mm and a length of a resin-formed body
being 250 mm in a liquid resin injecting and pouring machine, it is
preferable that a viscosity of the mixed and poured resin is 200 to
5000 poises and a pouring pressure is 0.5 to 15 MPa, though
depending on the number of mixing part of the conductivity giving
agent.
[0173] When the thickness of the resin formed body 12 is 4 mm in
the roller of the above mentioned dimensions, the diameter of the
resin injecting inlet of the metal mold is preferably 1 to 2 mm.
Further, as to the direction of the metal mold when pouring,
preferably the lengthwise direction of the metal mold stands
vertically for pouring from the lower part of the metal mold.
[0174] The metal mold may be heated depending on any arbitrary
methods. Specifically, for example, there is a method of heating in
a heating oven having heating fans, a method of heating by
arranging electric heaters around the metal mold, or a method of
heating by arranging induction heating coils around the metal
mold.
[0175] For the temperature of the metal mold, it is possible to
select any temperatures enabling to pour and hot-set the
thermosetting liquid resin, and at pouring the resin, desirable are
temperatures for easily pouring the resin and not hardening, for
example, 20 to 70.degree. C. The heating temperature of the resin
is preferably 80 to 200.degree. C., though depending on the amount
of a harden-retarding agent to be mixed in the resin.
[0176] As roller forming resin materials available to the inventive
forming method, resins of heat-removal hardening are employed, for
example, silicone, polyurethane, acrylonitrile.butadiene copolymer
(NBR), ethylene.propylene.diene.methylen copolymer (EPDM).
[0177] The thermosetting liquid resin may be added with other kinds
of additives as needed. For example, if a resistance controlling
agent as carbon is added, electric resistance of the roller can be
controlled.
[0178] As the above mentioned thermosetting liquid resin materials,
later explained hardening compositions may be used. The roller
forming resin composed of reaction hardening substance of the
hardening composition has an especially soft structure, and even if
the thickness is made thin, it displays enough an elastic effect.
Containing oxyalkylene unit in molecule, it has low viscosity
before hardening and is easily dealt, and containing saturated
hydrocarbon unit, it is low in water absorption rate, and
preferably cubic variation and variation of roller resistance are
low.
[0179] That is, it is preferable that the thermosetting liquid
resin material contains, as main components,
(A) polymer containing at least one alkenyl group in molecule and a
repeating unit composing a main chain being mainly oxy alkylene
unit or saturated hydrocarbon unit,
(B) a hardening agent containing at least two hydrosilyl group in
molecule,
(C) catalyst made hydrosilyl, and
(D) conductivity giving agent.
[0180] The thermosetting liquid resin is added, if necessary, with
materials for adjusting thermosetting reaction such as hardening
agent, hardening accelerator, hardening retardant or others. Or,
organic or inorganic fillers may be added. Further, some kinds of
organic or inorganic pigments, thickener or mold releasing agent
may be added.
[0181] Indefinite examples of the invention will be explained.
EXAMPLE A-1
[0182] The resin roller of the roller outer diameter being .phi.16
mm and the length of a resin formed body 12 being 250 mm was formed
by use of the metal mold 1 shown in FIG. 3.
[0183] The outer diameter of the core body 21 was 6 mm, and a
silicone tube of the inner diameter serving as the sealing member
26 being 4 mm, the outer diameter being 6 mm and the length being 5
mm was urged into and attached to the core body 21, and the
attaching position was designed such that the sealing member 26 was
compressed by 0.5 mm in the axial direction owing to the setting
force of the core supporting member 14.
[0184] The inner diameter of the concave part 17 of the core
supporting member 14 and the space of the end part 21a of the core
body 21 were 15.mu..
[0185] The used thermosetting liquid resin was 600 poises in the
viscosity in the mixed resin shown in the under table.
[0186] In the liquid resin injecting and pouring machine, the mixed
resin material was poured into the metal mold having the resin
injecting inlet 16 of 1.5 mm from the lower portion under the
pouring pressure of 4 MPa, the metal mold standing vertically in
the lengthwise direction.
[0187] The metal mold was arranged within the heating oven provided
with the heating fans and was heated by setting the atmospheric
temperature within the heating oven to be 140.degree. for 20
minutes and releasing from the metal mold, and a formed product was
obtained.
[0188] As a result, at the ends of the obtained roller, no resin
leakage occurred. TABLE-US-00001 TABLE 1 Components of hardening
compositions Wt parts (A) Terminal allylated polyoxypropylene based
polymer 100 (Number average molecular weight (Mn) 8000) (B)
Polysiloxane based hardening agent 6.6 (SiH value per 100 g: 0.36
mol) (C) 10% isopropyl alcohol solution of chloroplatinic acid 0.06
(D) Carbon black (made by Mitsubishi Co., Ltd. 7 Product name
"3030")
[0189] According to the invention, even if using the core body
having the same sizes in the center part of the core body (a part
of the resin-formed body) and the outer diameter of the end part
thereof, no resin leakage occurred at the rod portion of the resin
roller, and good products may be obtained cheaply and stably.
Embodiment 5
[0190] The resin roller 10a may be produced by use of the same
metal mold 120 as having explained with the prior example show in
FIG. 31.
[0191] In the metal mold 120, the core body 21 is in advance placed
and the thermosetting liquid resin is poured into the roller
forming space 15 through the resin injecting inlet 16 from the
resin injecting nozzle 18.
[0192] After completion of filling the resin in the metal mold 120,
the whole of the metal mold 120 is heated to hot-set the resin
charged in the roller forming space 15. Hot-setting the resin, the
core supporting members 14, 14 are removed upward and downward
respectively along an axial direction from the cylindrical metal
mold 13. Subsequently, the core body 21 is extruded from the
cylindrical metal mold 13 to take out a formed product 10b (roller
main body) held within the cylindrical metal mold 13. The roller
main body 10b is formed by providing the cylindrical resin layer
12a around the core body 21.
[0193] As the roller forming resin material usable to the inventive
forming method, a known thermosetting liquid resin is used. For
example, polyurethane, ethylene.propylene.diene.methylene copolymer
(EPDM) or silicone may be used, and it is more preferable to use
the thermosetting liquid resin material mixed with polysiloxane
based hardening agent.
[0194] The thermosetting liquid resin may be added with various
kinds of additives as needed. For example, if adding the resistance
controlling agent as carbon, the electric resistance of the roller
can be controlled.
[0195] The thermosetting liquid resin is added, if necessary, with
materials for adjusting thermosetting reaction such as hardening
agent, hardening accelerator, hardening retardant or others. Or,
organic or inorganic fillers may be added. Further, some kinds of
organic or inorganic pigments, thickener or mold releasing
agent.
[0196] The roller main body 10b produced by the above mentioned
forming method has the resin layer 12a swelling parts as seen in
FIG. 32 when releasing from the mold. A mechanism of the swelling
phenomenon at the edge is explained that the swelling is generated
by thermal expansion and shrinkage owing to temperature difference
between temperatures at pouring the resin into the metal mold and
after releasing from the mold, the amount of shrinkage in the axial
direction of the resin layer 12a is larger than that in the
peripheral direction, and the resin layer 12a is adhered to the
core body 21.
[0197] The cylindrical metal mold 13 and the core supporting
members 14, 14 have tolerances of respective parts and assembling
spaces, and so-called parting lines occur. If the spaces become
large owing to such as abrasion in the respective parts when
setting up the metal mold, the resin flows into the spaces and
burrs 75 are created as shown in FIG. 33.
[0198] Corners 74 swelling in the roller main body by dimensional
shrinkage or burrs are processed to round by the chamfering.
[0199] As to the process of the edges or corners, the machining or
polishing processes by known cutting edges or grinding stones, and
it is more preferable that previously heated metal-made heating
members 130 are, as shown in FIG. 7, contacted or approached to the
corners 74 at the edges of the roller main body 10b, and either of
the heating member 130 or the roller main body 10a is rotated to
thermally decompose and remove parts of the resin layer 12a,
otherwise a hot blast or a laser heating thermally decompose and
remove parts of the resin layer 12a.
[0200] The surface temperature of the heating member 130 is set to
be higher than thermally decomposing temperatures of selected
resins, and in case the resin layer 12a is formed with the
thermosetting liquid resin mixed with polysiloxane based hardening
agent in poly urethane or terminal allylated polyoxypropylene based
polymer, it is preferable that the surface temperature of the
heating member 130 is set to be 200.degree. C. or higher, in case
the resin layer 12a is formed with EPDM, 250.degree. C. or higher
is preferable, and in case of silicone, 350.degree. C. or higher is
preferable. For shortening the treating time, the above mentioned
respective temperatures should be desirably heightened around
50.degree. C. higher than said temperatures.
[0201] As to the process of the corner 74 at the edge of the resin
layer 12a, such a method may be also adopted which coats a solvent
to parts to be processed at the edge of the resin layer 12a for
dissolve to remove parts of the resin layer 12a.
[0202] Practically, preferable is a method that a solvent enabling
to dissolve the selected resin material is caused to soak into the
resin layer 12a of the roller main body 10b, and either of the
cloth, felt or the roller main body 10b is rotated to contact the
corner 74 at the edge of the resin layer 12a and dissolve to remove
the resin.
[0203] As to selection of solvents, in case the resin layer 12a is
formed with the thermosetting liquid resin mixed with polysiloxane
based hardening agent in poly urethane or terminal allylated
polyoxypropylene based polymer, available are keton based solvent
(for example, acetone, MEK) or hydrocarbon solvent (for example,
toluene, xylene) or ether based solvent (for example, diethyl
ether), if the resin layer 12a is formed with EPDM, hydrocarbon
solvent (for example, toluene, xylene) is usable, and if the resin
layer 12a is formed with silicone, acid or alkaline (for example,
hydrochloric acid, caustic soda) may be used. Using these solvents,
the corner 74 at the edge of the resin layer 12a can be dissolved
to remove.
[0204] Shapes of processed corner 74 at the edge of the resin layer
12a are desirably chamfered or circular-arc processed (rounding
process). It is preferable that the processed dimensions in both of
the axial and diameter directions are larger 1 to 40 times of a
swelling amount of the edge part having a larger diameter than the
center part of the formed roller main body 10b. Herein, the
swelling amount of the edge part is meant by a dimension until the
opposite face of the swelling part of the edge parts on the basis
of the extending face of the center position of the resin layer 12a
of the roller main body. For example, if the swelling amount is
100.mu., it is sufficient that the edge part of the resin layer.
12a is 100 .mu.m to 4 mm chamfered or circular-arc processed from
the edge face of the resin layer 12a in the axial direction and is
100 .mu.m to 4 mm chamfered or circular-arc processed from the
reference face in the diameter direction.
[0205] If the processed dimension of the corner 74 at the edge part
of the resin layer 12a is smaller than the above mentioned ranges,
an effect of contributing to a long life of the surface layer 12b
is small, and if exceeding said ranges, the length in the axial
direction necessary to developing of the resin roller is short, and
consequently, the length of the resin roller 10a in the axial
direction should be large, and in turn an apparatus is large
scaled.
[0206] In a case of the resin layer 12a having the low rubber
hardness, if contacting to the cutting edge or the grinding stone
in the machining or polishing processes, the surface of the resin
layer 12a becomes concave or chatter appears in the surface, and
the surface is difficult to be machined or polished.
[0207] Thus, in case such a method is selected that the corner 74
is heated by chamfering or rounding to thermally dissolve the resin
from the corner 74, or the solvent is coated to the corner 74 to
dissolve the resin therefrom, if using the thermosetting liquid
resin of the formed rubber hardness being 25.degree. or lower
(JIS-A), the process is effective and desirable.
[0208] After releasing the roller main body 10b having the core
body 21 and the resin layer 12a from the metal mold 120, and
chamfering or rounding the corner 74 swelling larger in the
diameter than the center part of the resin layer 12a of the roller
main body 10b by shrinking of the dimension or occurrence of burrs,
the surface layer 12b is coated and hardened around the resin layer
12a of the roller main body 10b.
[0209] No especial limitation is made to materials forming the
surface layer 12b, but from viewpoint of causing the developing
agent to well minus-charge, nylon based (polyamide group) or
polyurethane based materials are preferable, and fluoro rubber is
desirable from viewpoint of causing the developing agent to well
plus-charge.
[0210] No especial limitation is also made to coating methods of
the surface layer 12b, and ordinary are a method of covering a tube
on the surface layer 12b by the thermal shrinkage, or a method of
applying the solution enabling to form the surface layer 12b by
means of dipping, spraying or coater in response to viscosity and
drying it.
[0211] Indefinite examples of the invention will be explained.
EXAMPLE B-1
[0212] As the thermosetting liquid resin material, a resin raw
material was used where polysiloxane based hardening agent and the
conductivity giving agent (carbon black) were mixed in terminal
allylated polyoxypropylene based polymer shown in Table 1.
[0213] This resin raw material was used to form a roller min body
10b of an outer diameter being .phi.16 mm and a length of a resin
layer 12a being 250 mm in the liquid resin injecting and pouring
machine by use of the metal mold 120 shown in FIG. 31.
[0214] A viscosity of the mixed and poured resin was 600 poises,
and a pouring pressure was 2 MPa. The diameter of the resin
injecting inlet provided in the core supporting member 14 of the
metal mold 120 was 1.5 mm, and the metal mold 120 was directed,
standing vertically in the lengthwise direction, and the mixed
resin material was poured into the metal mold from the lower
portion.
[0215] The metal mold 120 was arranged within the heating oven
provided with the heating fans and was heated by setting the
atmospheric temperature within the heating oven to be 140.degree.
C. for 20 minutes, and releasing from the metal mold 120, a formed
product (roller main body) was obtained.
[0216] As a result, it was observed that the corner 74 at the edge
part of the resin layer 12a of the roller main body 10b swelled
100.mu. in comparison with the outer diameter of the center part of
the resin layer 12a.
[0217] The roller main body was attached at both end shafts to a
rotary machining disc, and soldering irons (30 w) heated at around
300.degree. C. were contacted to the corners 74 for 5 minutes, and
the roller main body was rotated to fuse and remove the resin of
the corner.
[0218] As a result, the roller main body was obtained, which was
smoothly rounded 1 mm from the edge part in the axial direction and
1 mm from the surface in the diameter direction.
[0219] The solid content of the mixture shown in Table 2 was
diluted to 5% with a mixed solvent of DMK (N,N-dimethyl formamide):
MEK (methyl ethyl ketone)=1:1 (weight ratio), and was still left
for one hour to make a solution, and the resin for forming the
surface layer was carried out dipping around the resin layer of the
roller main body and dried to form the surface layer.
[0220] The thus obtained resin roller was installed to contact a
.phi.30 mm sensitive drum at a 2 mm width, and when the resin
roller was continuously rotated at rotation number of 240 rpm to
perform an endurance test, the surface layer did not peel until 16
hours.
COMPARATIVE EXAMPLE B-1
[0221] The roller main body formed in Example B-1 was not chamfered
nor rounded at the corners, the surface layer of which was coated
and dried similarly to the above procedure, and the resin roller
was obtained.
[0222] The obtained resin roller was subjected to the endurance
test under the same conditions as above, and after 3.5 hours
[0223] the surface layer of the corner started to peel, and after 4
hours of the test, the peeling of the surface layer spread toward
the center part from the edge parts. TABLE-US-00002 TABLE 2
Components of the composition of the surface layer Wt. parts
Polycarbonate urethane 100 Acrylic fine particles 30
[0224] According to the invention, the resin layer is formed by
pouring the thermosetting liquid resin into the forming metal mold
and hot-setting it, and the resin layer is chamfered or rounded at
the corners of the edge parts, followed by forming the surface
layer on the surface of the resin layer, and therefore, the film of
the surface layer can be made a desired thickness over the full
face of the roller, and the surface layer is restrained from
exfoliation or abrasion from the resin layer, so that the
durability of the resin roller is increased, and consequently, the
inventive resin roller can be served for a long period of time
without exchanging many kinds of rollers employed in
electrophotographic system such as laser printers, copiers,
facsimile devices using the resin rollers.
Embodiment 6
[0225] The roller producing apparatus is, as shown in FIG. 9,
mainly composed of the cylindrical metal mold 1 and the upper and
lower core supporting members 2a, 2b, and the upper core supporting
member 2a is equipped with a mold inner pressure adjusting
mechanism 220 for adjusting the inner pressure of the metal
mold.
[0226] The cylindrical metal mold 1 is inserted with the core body
21, and the core body 21 is inserted at both ends in axis receiving
holes 3 formed in the core supporting member 2a, 2b fitted in both
upper and lower opening parts of the cylindrical metal mold 1,
whereby the core body 21 is supported at the center position of the
cylindrical metal mold 1.
[0227] The cylindrical metal mold 1 is shaped in seamless pipe, and
the inside face is preferably performed with fluorine resin coating
or electroless plating from the viewpoint of releasing from the
mold.
[0228] On the other hand, the upper and lower core supporting
members 2a, 2b are defined with convex parts 4 for fitting inward
the cylindrical metal mold 1 to form a concave-convex fitting with
the cylindrical metal mold 1, a so-called faucet structure. The
outer peripheral faces 5 of the core supporting members 2a, 2b for
fitting the inner peripheral face of the cylindrical metal mold may
be tapered. By being tapered, the core supporting members 2a, 2b
are easily detachably attached to the cylindrical metal mold 1, and
the axis receiving holes 3 can be securely positioned at the center
position in the axial direction of the cylindrical metal mold
1.
[0229] Preferably, the cylindrical metal mold 1 and the outer
diameters of the core supporting members 2a, 2b have the same size.
The core supporting members 2a, 2b and the cylindrical metal mold 1
may be tightened by screwing or clamping, though not shown.
[0230] The lower core supporting member 2b is provided with a
pouring hole 6 for pouring the liquid resin, and for this hole, a
closure mechanism 7 is provided to check counterflow of an expanded
resin in the metal mold at hot-setting. The exemplified closure
mechanism 7 is crossed in the pouring hole 6 with a pin 8 having a
reduced diameter part on the way in the lengthwise direction, and
by moving the pin 8 back and forth, a releasing condition of
positioning the reduced diameter part in the pouring hole 6 is
switched with another closing condition. In addition, the pouring
hole 6 communicates with a nozzle touch part 9 formed by recessing
in semi-sphere in the lower face of the core supporting member 2b,
and if pressing the pouring hole 6 to a nozzle (not shown) having a
front end of the semi-sphere corresponding to the nozzle touch part
9, an excellent sealing performance is displayed and the liquid
resin can be supplied without leakage.
[0231] FIG. 10 shows in detail the mold inner pressure adjusting
mechanism 220 provided in the upper core supporting member 2a for
adjusting inner pressure of the roller forming space 10.
[0232] The mold inner pressure adjusting mechanism 220 as shown in
FIG. 10 has a spare room 221 of variable volume whose inner space
communicates with the roller forming space 100 via a narrow hole
222.
[0233] The volume in the spare room 221 is varied to adjust the
inner pressure in the roller forming space 100, and the adjustment
is carried out, aiming at maintenance of constant values of the
inner pressure as passing a time of hot-setting, so as not to
exceed the inner pressure when hot-setting the thermosetting liquid
resin. Structures enabling such adjustment are variously assumed,
and a representative one may be exemplified as shown in that the
spare room 221 is provided inside with a plunger vertically moving
under an air tight condition, and the plunger 224 is pressed
downward by a spring 223. Preferably, the mold inner pressure
adjusting mechanism 220 is provided at the upper side of the metal
mold in relation with attachment.
[0234] The mold inner pressure can be adjusted by selecting spring
constant of the mold inner pressure adjusting mechanism 220.
Practically, when the mold inner pressure is 0 kg/cm.sup.2, the
volume in the spare room is 0, and as the mold inner pressure
rises, the spring mechanism is compressed, and the volume in the
spare room increases by the amount of compression. A state of the
mold inner pressure being 0 kg/cm.sup.2 means such a state that the
liquid resin is not fully charged in the roller forming space 100,
and under this state, the liquid resin does not go into the spare
room 221, and an edge face 224 of the plunger is placed at the
undermost part as shown with an two-dotted imaginary line, and the
volume of the spare room 221 is 0. By the way, there is furnished
an instrument for discharging an air compressed in company with the
resin pouring into the roller forming space 100, though not
shown.
[0235] When completing the charge of the liquid resin into the
roller forming space 100 and accomplishing fullness of the liquid
resin into the roller forming space 100, an operation starts to
hot-set the liquid resin, and when hot-setting, the liquid resin is
expanded and flows into the spare room 221 through the narrow hole
222. Preferably, the volume in the spare room when the spring is
fully compressed is set to be 5% or more of the roller forming
space 100. It is desirable to set the spring constant such that the
mold inner pressure is 100 kg/cm.sup.2 or lower when the spring
mechanism is fully compressed, and more desirable is to set 60
kg/cm.sup.2 or lower. If the mold inner pressure exceeds 100
kg/cm.sup.2 when hot-setting, the resin leaks into the parting line
between the cylindrical metal mold 1 and the core supporting
members 2a, 2b to generate burrs. The diameter of the narrow hole
222 communicating the roller forming space 100 with the spare room
221 is desirably set to be .phi.1 mm to .phi.3 mm for cleaning
easiness. The outer diameter d of the roller is practically
expressed with the following formula, though depending on the
amount of the resin flowing into the spare room 221.
d=(4.times.(V-V1)/(.pi..times.L))1/2 herein; V: Volume of the
forming space V1: Amount of the resin flowing into the spare room
L: Length of the part of the roller elastic layer.
[0236] An inventor has found that if the outer diameter of the
roller is expressed by introducing an parameter of an cross
sectional shrinkage percentage .alpha., the inner pressure at
hot-setting can be evaluated in relation with the cross sectional
shrinkage percentage .alpha., and values of the cross sectional
shrinkage percentage .alpha. when easily releasing from the mold
and creating no burr, fall within an almost fixed range even if the
roller sizes or thickness of the elastic layer are different, and
if the inner pressure when hot-setting is fixed, this .alpha. is
also fixed accordingly. The cross sectional shrinkage percentage
.alpha. is expressed with the under formula.
.alpha.=(D2-d2)/(D2-ds2) herein, the symbols mean as follows. D:
Inner diameter d: Outer diameter of the roller ds: Outer diameter
of the core body (Core diameter).
[0237] As a result of study, it was found that the cross sectional
shrinkage percentage .alpha. of easily releasing from the mold by a
bit cooling and creating no burr is 0.02 to 0.06. The outer
diameter d of the roller is a value when measuring at a room
temperature.
[0238] If the cross sectional shrinkage percentage .alpha. is
smaller than 0.02, the releasing from the mold is easily inferior
and burrs are outstanding on the circumference of the elastic
layer. On the other hand, if the cross sectional shrinkage
percentage .alpha. is larger than 0.06, voids easily occur inside
and on the surface of the elastic layer, and variations of the
outer diameter are easy to grow in the axial direction.
[0239] Further, it has been found that the mold inner pressure at
hot-setting for .alpha. to fall in the range of 0.02 to 0.06 is 100
kg/cm.sup.2 or lower.
[0240] As the value of the preferable cross sectional shrinkage
percentage .alpha. is apparent, it is possible to design the metal
mold for obtaining rollers of easily releasing from the mold
without creating burrs. For example, when the inner diameter D of
the cylindrical metal mold is .phi.16 mm and the core diameter is
.phi.10 mm, the outer diameter d of the cross sectional shrinkage
percentage .alpha. being 0.02 is .phi.15.90 mm. Further, the outer
diameter d of the cross sectional shrinkage percentage .alpha.
being 0.06 is .phi.15.70 mm. In short, the roller outer diameter
for good forming ranges .phi.15.70 mm to .phi.15.90 mm.
[0241] The invention has been explained, referring to one
embodiment, and of course, the invention may be applied to another
apparatus of a structure which holds the roller forming space
between both ends of the cylindrical metal mold inserted inside
with the core body for disposing the core supporting members.
[0242] Explanation will be made to experiments carried out for
confirming effects of the invention.
EXAMPLE C-1
[0243] The roller producing apparatus shown in FIG. 9 was used. The
cylindrical metal mold was treated on the inside with the
electroless plating and the inner diameter was .phi.16.00 mm. The
outer diameter of the core body was .phi.10 mm, a maximum volume of
the spare room was 1.6 ml, and the spring mechanism was absent
(corresponding to the spring constant 0). The thermosetting liquid
resin (silicone group) was poured at 20.degree. C. from the lower
pouring hole, and after filling the resin in the forming space, the
closure mechanism was closed. At that time, the mold inner pressure
adjusting mechanism was checked with a stopper not to move together
with increasing of the mold inner pressure at pouring. When
completing the pouring, the mold inner pressure was 0.
Subsequently, the resin was hot-set 140.degree. C..times.20 min in
a hot blast oven, cooled and released from the mold. Thus, the
elastic rollers were produced. The rollers were evaluated. Testing
number were 10 pieces, average outer diameters of the rollers were
.phi.15.77 mm and variations of the outer diameter was 15 .mu.m.
Results were as follows. The evaluations of the resin leakage were
performed by evaluating the burr occurrence in the parting line
being the fitting part between the cylindrical metal mold and the
upper and lower core supporting members and by evaluating the resin
leakage from the closure mechanism part provided on the way of the
pouring hole 6 (called as "lower closure mechanism part"). A method
of releasing from the mold was to secure the cylindrical metal mold
under a condition of taking off the upper and lower core supporting
members, and push the shaft of the formed body at the front end
thereof by the rod, and the pushing load at that time was measured
by a load cell. Results were as follows.
[0244] Mold releasing load: 15 kg (No scratch at releasing)
[0245] Burr condition: No at the parting line part
[0246] Resin leakage: No at the lower closure mechanism part
[0247] Roller average outer diameter: .phi.15.77 mm.
[0248] Variation of the outer diameter: 15 .mu.m
EXAMPLE C-2
[0249] The spring mechanism was set such that the maximum value of
the mold inner pressure was 60 kg/cm.sup.2. The shape of the spare
room was .phi.10 mm.times.maximum length of 20 mm, and the spring
mechanism had the spring constant of (.pi./4).times.12.times.60=47
kg/20 mm. Other conditions were the same as those of Example C-1.
Results were as follows.
[0250] Mold releasing load: 15 kg (No scratch at releasing)
[0251] Burr condition: No at the parting line part
[0252] Resin leakage: No at the lower closure mechanism part
[0253] Roller average outer diameter: .phi.15.84 mm
[0254] Variation of the outer diameter: 20 .mu.m
EXAMPLE C-3
[0255] The spring mechanism was set such that the maximum value of
the mold inner pressure was 100 kg/cm.sup.2. Other conditions were
the same as those of Examples C-1 and C-2. Results were as
follows.
[0256] Mold releasing load: 40 kg (No scratch at releasing)
[0257] Burr condition: No at the parting line part
[0258] Resin leakage: No at the lower closure mechanism part
[0259] Roller average outer diameter: .phi.15.88 mm
[0260] Variation of the outer diameter: 18 .mu.m
COMPARATIVE EXAMPLE C-1
[0261] The spring mechanism was set such that the maximum value of
the mold inner pressure was 150 kg/cm.sup.2. Other conditions were
the same as those of Examples C-1 and C-2. Results were as
follows.
[0262] Mold releasing load: 100 kg (Rubbed scratch on surface)
[0263] Burr condition: Present at the parting line part
[0264] Resin leakage: Present at the lower closure mechanism
part
[0265] Roller average outer diameter: .phi.15.93 mm
[0266] Variation of the outer diameter: 18 .mu.m
COMPARATIVE EXAMPLE C-2
[0267] The inner pressure adjusting mechanism provided at the upper
core supporting member was taken off, and the resin was hot-set
under the condition of opening the narrow hole communicating the
spare room with the roller forming space. Other conditions were the
same as those of the above Examples. Results were as follows.
[0268] Mold releasing load: 18 kg (Rubbed scratch on surface)
[0269] Burr condition: Present at the parting line part
[0270] Resin leakage: Present at the lower closure mechanism
part
[0271] External appearance: Void occurring
[0272] Roller average outer diameter: .phi.15.68 mm
[0273] Variation of the outer diameter: 50 .mu.m
COMPARATIVE EXAMPLE C-3
[0274] The inner pressure adjusting mechanism provided at the upper
core supporting member was taken off, and the resin was hot-set
under the condition of plug-stopping the narrow hole communicating
the spare room with the roller forming space. Other conditions were
the same as those of the above Examples. Results were as
follows.
[0275] Mold releasing load: 140 kg (Rubbed scratch on surface)
[0276] Burr condition: Present at the parting line part
[0277] Resin leakage: Present at the lower closure mechanism
part
[0278] Roller average outer diameter: .phi.15.96 mm
[0279] Variation of the outer diameter: 18 .mu.m
EXAMPLE C-4
[0280] The roller of the center diameter of the core body being
.phi.12 mm was used. Other conditions were the same as those of
Example C-2. Results were as follows.
[0281] Mold releasing load: 40 kg (No scratch)
[0282] Burr condition: No at the parting line part
[0283] Resin leakage: No at the lower closure mechanism part
[0284] Roller average outer diameter: .phi.15.00 mm
[0285] Variation of the outer diameter: 18 .mu.m
COMPARATIVE EXAMPLE C-4
[0286] The roller of the center diameter of the core body being
.phi.12 mm was used. Other conditions were the same as those of
Example C-2. Results were as follows.
[0287] Mold releasing load: 100 kg (Rubbed scratch)
[0288] Burr condition: No at the parting line part
[0289] Resin leakage: No at the lower closure mechanism part
[0290] Roller average outer diameter: .phi.15.00 mm
[0291] Variation of the outer diameter: 14 .mu.m
[0292] From the above mentioned results, the following is seen.
[0293] If adjusting the mold inner pressure to be 100 kg/cm.sup.2
or lower, it is possible to avoid almost perfectly the burr
occurrence at the parting line part or the resin leakage from the
lower closure mechanism part. The product can be released from the
mold at low load without causing scratches at releasing.
[0294] On the other hand, if the mold inner pressure exceeds 100
kg/cm.sup.2, burrs occur and the resin leaks from the lower closure
mechanism part. Besides, the mold releasing load is large, and
badness appears by releasing the mold as scratches remain. This
face is applicable to even if the elastic layers are different in
thickness, and it has been found that if the elastic layer is
smaller than 1 mm, the mold releasing load is large, even if the
mold inner pressure is lower than 100 kg/cm.sup.2; and scratches at
releasing the mold remain. From these occasions, for carrying out
the roll formation of easily releasing from the mold without
creating scratches and burrs, it has been confirmed that the mold
inner pressure at hot setting is adjusted to be 100 kg/cm.sup.2 or
lower, and the inner diameter D and the outer diameter d of the
cylindrical metal mold are selected such that the thickness of the
elastic layer is 1 mm or more.
[0295] In the invention equipping the core supporting member with
the mold inner pressure adjusting mechanism, as the mold inner
pressure at hot-setting can be adjusted, various defects caused by
excessive inner-pressure can be prevented. In particular, if
hot-setting by adjusting the mold inner pressure to be 100
kg/cm.sup.2 or lower, the resin leakage can be avoided at the
parting line part between the cylindrical metal mold and the core
supporting member or the lower closure mechanism part, and products
without burrs, so that it is possible to largely reduce a secondary
process as the burr removal or the adhered resin removal from the
mold after producing rollers. Further, since products can be
released from the metal mold at low load, it is not necessary to
coat the mold releasing agent to the inside the cylindrical metal
mold, and no scratches occur by releasing from the mold. Besides,
as the mold inner pressure is 100 kg/cm.sup.2 or lower, pressure
proof required to the metal mold may be low, and such a metal mold
having thin thickness and weight light structure can be used, and
cooling for a long time is not necessary for heightening the
property of releasing from the mold, so that productivity is
increased.
Embodiment 7
[0296] FIG. 11 is a schematically structured view for explaining
the roller producing method using the thermosetting liquid resin
and the producing apparatus of the invention. The exemplified
roller producing apparatus 101 is equipped with a container 102A
storing the thermosetting liquid resin containing a catalyst
(called as "A liquid" hereafter), a container 102B storing the
thermosetting liquid resin containing a cross linking agent (called
as "B liquid" hereafter), an injecting device 103 having a
measuring mechanism for measuring these thermosetting liquid
resins, a mixing mechanism 104 for mixing both thermosetting liquid
resins, a roller forming metal mold filled with the mixed resin
into an inside forming space 106a via a resin injecting 105, and
transferring pipes 107A, 107B connecting between the containers and
devices for passing the liquid resin. Herein, the respective liquid
resins in the containers 102A, 102B are added with a conductivity
giving agent, and the containers 102A, 102B are furnished with
force feed pumps 108A, 108B for forcing to feed the respective
liquid resins to the transferring pipes 107A, 107B. The injecting
device 103 is also equipped with temperature adjusting means 109A,
109A, . . . 109B, 109B . . . for adjusting the thermosetting liquid
resin to be at desired temperatures. There is not provided a
cooling mechanism for cooling the liquid resin as the prior
art.
[0297] Sequence for producing the elastic roller of the invention
by means of the above structure of the apparatus will be explained
in detail.
[0298] At first, as the thermosetting liquid resin, the A liquid
added with the catalyst and the conductivity giving agent in a base
polymer (main agent) and the B liquid added with the cross linking
agent and the conductivity giving agent in a base polymer (main
agent) are prepared, measured respectively and stored in the
container 102A and the container 102B. For these containers 102A,
102B, pale cans on the market are standardized, cheap, much
available, and convenient. The liquid A and the liquid B are
de-foamed in vacuum, agitated, mixed and stored. As an agitation
de-foaming mechanism, generally the containers 102A, 102B are
attached to a turn table and rotated to agitate with agitating
vanes while reducing pressure by a vacuum pump.
[0299] The thus prepared A liquid and B liquid are forcibly sent to
the injection device 103 through the transferring pipes 107A, 107B
as a flexible hose, and measured to be desired weight by respective
cylinders 111A, 111B. Next, the measured liquid resins in the
cylinders go forward through screws 112A, 112B and are jetted, pass
through the resin injecting 106b of the metal mold 106 from the
injecting nozzle 105 as being mixed by the mixer 104, and are
filled into the cavity composing the roller forming space 106a. The
mixing mechanism 104 makes no especial limitation if enabling to
stand and mix against the jetting pressure of the liquid resin, and
ordinarily, either of a dynamic mixer and a static mixer is served.
The static mixer has a structure provided with the mixing vanes
having a plurality of spirally twisted continuous elements at the
inside space of the mixing mechanism, divides a fluid running in
the inside space into two parts by means of the mixing vanes, and
jets it out. The dynamic mixer has a mixing rotor rotating screws
or gears in the inside space of the mixing mechanism, mixes
uniformly the fluid running in the inside space by means of the
mixing rotor, and jets it out.
[0300] In the range from the raw material containers 102A, 102B to
the injecting device 103, as the liquid resin is divided in the A
liquid and the B liquid, the cross linking reaction does not occur,
so that a cooling procedure as the conventional technical knowledge
for cooling the thermosetting liquid resin is unnecessary. Both
liquids are mixed in the mixing mechanism 104, and since at the
same time as mixing, the mixed resin is continuously jetted at high
pressure into the forming space 106s of the roller forming metal
mold 106, the liquid resin is scarcely adhered and solidified to
the inside wall faces of the mixing mechanism 104 or the pouring
nozzle 105. That is, the liquid resin in the mixing mechanism 104
is periodically replaced by continuously forming, so that the
liquid resin does not stay in the mixing mechanism for a long
period of time and is hardly solidified by the cross linking
reaction. Thus, the cooling procedure necessary in the prior art is
unnecessary, thereby enabling to accomplish a low cost of a
facility.
[0301] For avoiding the cross linking reaction of the mixed liquid
in the range from the mixing mechanism 104 to the pouring nozzle
105, temperatures of the liquid resin at injecting is set to be 20
to 70.degree. C., preferably 20 to 60.degree. C. Therefore, the
heaters 109A, 109A, . . . 109B, 109B . . . are arranged around the
cylinders 111A, 111B. If heating the liquid resin exceedingly
60.degree. C., the cross linking reaction gradually progresses, the
resin component is solidified and accumulated on the wall in the
mixing mechanism, and the mixing efficiency goes down and the
quality is much probably varied.
[0302] In addition, the viscosity of the base polymer of the liquid
resin is adjusted, or the liquid resin before pouring is heated by
the temperature adjusting means for preferably adjusting the
viscosity of the liquid resin at injecting to be 5000 poises or
lower. If pouring the liquid resin of the viscosity exceeding 5000
poises, the pressure effecting to the metal mold becomes high and
the structure of the metal mold should be thick, and for decreasing
said pressure, the pouring time of the liquid resin should be
extended, and further at pouring, an air within the cavity is
easily involved into the pouring and the number of pouring holes
must be increased.
[0303] As is seen, in the invention, the liquid resin is not
adhered nor solidified to the transferring pipes 107A, 107B, the
cylinders 111A, 111B, the mixing mechanism 104 and the pouring
nozzle 10, so that the frequency and necessity of dissembling to
clean the apparatus are extremely decreased. As the liquid resin of
low viscosity can be injected at temperatures near a room
temperature, it is not necessary to make the thick structure of the
roller forming metal mold 106, and when hot-setting the liquid
resin injected to the forming space 106a, the heating load is not
increased and the hardening reaction is sufficient with a short
time, so that a producing cycle is remarkably heightened.
Practically, a main maintenance is enough to only the mixing
mechanism, and such merits appear that the frequency and labor
therefor are considerably reduced.
[0304] Besides, in the invention, being different from the liquid
resin of the existing one liquid, there is little risk of
increasing viscosity by the cross linking reaction of the liquid
resin in the container.
[0305] Next, the base polymers to be used to the A liquid and the B
liquid are components hardening by making hydrosilyl with the cross
linking agent. Specifically, since the base polymer has at least
one alkenyl group in molecule, the hydrosilyl reaction occurs and
becomes a high molecular condition and is hardened, and a repeating
unit composing a main chain is polymer mainly comprising oxy
alkylene unit or saturated hydrocarbon unit, for example, a
silicone based addition reacting typed liquid resin is a typical
example thereof. The number of alkenyl group in the base polymer
should be at least one for the hydrosilyl reaction with the cross
linking reaction, and from the viewpoint of obtaining good rubber
elasticity, in a case of molecule in a straight chain, two alkenyl
groups are placed at both terminals of molecule, and in a case of
molecule having branches, it is desirable that two or more alkenyl
groups are placed at both terminals of molecule.
[0306] In a case that the repeating unit composing the main chain
is polymer mainly comprising oxy alkylene unit or saturated
hydrocarbon unit, if a small amount of the conductivity giving
agent is added, volume resistivity of 104 to 1012 .OMEGA.cm
favorable to the roller is available. Herein, oxyalkylene based
polymer is meant by such polymer containing 30 wt % or more
oxyalkylene unit among units composing the main chain, preferably
50 wt % or more, and as a starting material when making polymer for
composing a remainder excepting oxyalkylene unit, compound
containing two or more of active hydrogen, for example, ethylene
glycol, bisphenol based compound, glycerine, trimethylol propane,
pentaerythritol are taken up.
[0307] On the other hand, if the repeating unit composing the main
chain in said base polymers is polymer comprising saturated
hydrocarbon unit, it has a low water absorption rate and is
preferable for obtaining rollers small in environmental variation
of electric resistance. This polymer is also a component of making
hydrosilyl reaction with the cross linking agent similarly to the
above mentioned oxyalkylene based polymer and becoming hardened,
and a component becoming high molecule by causing hydrosilyl
reaction owing to alkenyl group existing in molecule and hardened.
Actually exemplified are isobutylene based polymer,
hydroisobutykene based polymer, or hydrobutadiene. These polymers
may contain the repeating units of other components such as
copolymer, and it is important for not spoiling the characteristics
of obtaining the rollers having a low water absorption rate and
being small in environmental variation of electric resistance to
contain saturated hydrocarbon unit 50 wt % or more, preferably 70
wt % or more.
[0308] The components contained in the cross linking agent are
sufficient with compounds having at least two hydrosilyl group in
molecule, and if the number of hydrosilyl group contained in
molecule is to too much, hydrosilyl group easily much remains in
hardened substances to cause voids or cracks, and so it is
preferable to adjust the number to be 50 or less, more preferably 2
to 30 from the viewpoint of controlling rubber elasticity of the
hardened substances and making storing stability favorable. In the
invention, having one of hydrosilyl group is meant by having one of
H to be combined with Si. Therefore, in a case of SiH.sub.2,
hydrokysillyl is two, but if H to be combined with Si is combined
with different Si, such combination is preferable from viewpoint of
hardenability and the rubber elasticity.
[0309] The molecular amount of the cross linking agent is
preferably adjusted to be 30,000 or less in number average
molecular amount (Mn) from the viewpoint of making workability of
product rollers good, more preferably 300 to 15,000 in Mn from the
viewpoint of reactivity or compatibility with said base
polymer.
[0310] As to the cross linking agent, considering that cohesive
force is larger than that of the cross linking agent, it is
important in the compatibility to have modification containing
phenyl group, and in an easy availability, styrene modification is
suited, and in a storing stability, .alpha.-metyl styrene is
suited.
[0311] The above catalyst is enough if it can be used as a hydro
sillyl catalyst, and is not especially limited. As to the using
amount of the catalyst, 10-8 to 10-1 mol, further 10-8 to 10-6 mol
per 1 mol of the alkenyl group in base polymer (main agent)
component are preferable from the viewpoint of avoiding check of
hardening by catalyst poisoning and good balancing between
appropriate pot life and low cost. As these catalysts, for example,
enumerated are platinum simplex, catalyst causing simplex as
alumina to carry platinum, chloro platinic acid (including complex
as alcohol), complex of platinum, metallic chlorides of rhodium,
ruthenium, iron, aluminum, titanium. Among them, in the point of
catalytic activity, preferable are chloro platinic acid, platinum
olfin complex, platinum vinyl siloxane complex. The catalyst may be
used sole or co-used two kinds or more.
[0312] If using conductive composition added with conductivity
giving agent in the above mentioned resin compositions, such
rollers are produced which are suited as rollers functioning for
electrophotography. As the conductivity giving agent, carbon black
is good. The conductivity giving agent is in advance mixed with
base polymer by means of a roll mixer, and the mixture is added
respectively to the A liquid and the B liquid such that the cross
linking reaction moderately when both liquids are measured 1:1.
Practically, in each solution, preferably the conductivity giving
agent is 1 to 35 wt % added to base polymer, and added at the same
amount to the A liquid and the B liquid to provide viscosity at
substantially the same level. This is why if both liquids are
considerably different in the viscosity, the mixing efficiency goes
down and the crossing linking reaction is less to advance. For
example, if adding the conductivity giving agent to only the A
liquid or the B liquid, the adding amount is about 40 wt % to
largely bring up the viscosity of one side liquid, so that the
mixing efficiency is remarkably lowered.
[0313] To the above mentioned resin composition, a filler, a
preservation stabilizing agent, a plasticizer, an ultraviolet
absorbing agent, a lubricant and a pigment may be added
appropriately.
[0314] The thermosetting liquid resin injected into the roller
forming metal mold 106 is heated to generate the cross linking
reaction, hardened and is formed to agree with the shape of the
roller forming space 106a into such as cylindrical form. At both
ends in the axial direction of the roller main part as the product,
the supporting shafts are formed for attaching to bearings of the
electrophotographic apparatus. The supporting shaft is formed by
penetrating or disposing the shaft body composed of a stainless
steel or an iron in an axis of the cylindrical roller, otherwise
forcing, adhering or pinning the shaft body in an attaching hole
formed in the axes of both ends of the main body.
[0315] As mentioned above, according to the roller producing method
and the apparatus thereof using the thermosetting liquid resin of
the invention, the roller forming metal mold is prepared, the
thermosetting liquid resin containing the cross linking agent and
the thermosetting liquid resin containing the catalyst are
separately stored in the respective containers, measured to be
predetermined amounts, injected into the roller forming space while
both thermosetting liquid resins are being mixed in the mixing
mechanism, and hot-set to form the main body, and therefore, (1)
until being injected into the roller forming space, the
thermosetting liquid resin is not caused with the cross linking
reaction, and since the liquid resin is not adhered nor solidified
to the inside walls of the transferring pipes and the cylinders,
and the pouring nozzle 105, the frequency and necessity of
disassembling to clean the apparatus are extremely decreased, and
(2) since the cooling procedure of the liquid resin is not required
until the injection, and the liquid resin of low viscosity can be
injected at temperatures near a room temperature, it is not
necessary to make the thick structure of the roller forming metal
mold 106, and when hot-setting, the heating load is not increased
and the hardening reaction is sufficient with a short time, so that
a producing cycle is remarkably heightened and the production cycle
is markedly improved, and the cost-down is possible by unnecessary
facility of the cooling mechanism.
[0316] By the temperature adjusting instrument, the temperature of
the thermosetting liquid resin at injection is adjusted to be 20 to
70.degree. C., thereby enabling to securely prevent the liquid
resin from solidification.
Embodiment 8
[0317] With reference to FIGS. 12 to 14, explanation will be made
to the embodiment of the injection forming apparatus according to
the invention. FIG. 12 A is a plan view of the apparatus of the
invention and B is a bottom view thereof. FIG. 13 is a schematic
view showing the side view of the apparatus (the cross sectional
view A-A of FIG. 12A) FIG. 14 is enlarged cross sectional views of
elementary parts of the present apparatus.
[0318] The injection forming apparatus 301 of this embodiment is
composed of the cylindrical metal mold 304 inserted inside with an
alloy-made core body 303, the injection forming metal mold 302
composed of the core supporting members 305, 306 fitted inside to
both edge parts in the axial direction of the cylindrical metal
mold 304 as holding both edges 303a, 303b of the inside inserted
core body 303, and the heating mechanisms 307, 308 disposed around
the injection forming metal mold 302 and holding said metal mold
302 at both sides in the diameter direction. Further, the inside of
the cylindrical metal mold 304, the core main part 303c and the
core supporting members 305, 306 form the roller forming space 317
for introducing the resin material.
[0319] Both ends 303a, 303b of the core body 303 are set and held
in core supporting holes 305a, 305b formed in the core supporting
members 30, 306. In this embodiment, the core body 303 has steps
between both ends 303a, 303b to be fitted in the core supporting
holes 305a, 306a and the core main body 303c, but is not limited
thereto, and a straight type without steps is enough.
[0320] The cylindrical metal mold 304 is shaped in seamless pipe,
and the inside face is preferably performed with fluorine resin
coating or electroless plating from the viewpoint of releasing
products from the mold. The upper and lower core supporting members
305, 306 have almost the same outer diameter as that of the
cylindrical metal mold 304, and the lower core supporting member
306 is formed with a resin injecting inlet 306b for filling the
resin material in the roller forming space 317, while the upper
core supporting member 305 is formed with a gas venting hole 305b
for releasing gas pressure effected by the filled resin. As shown
in FIG. 14A, at the lower end of the core supporting member 305, a
fitting projection 305c is formed for fitting inside the
cylindrical metal mold 304, and as shown in FIG. 14B, also at the
upper end of the core supporting member 306, a fitting projection
306c is formed for fitting inside the cylindrical metal mold 304, a
so-called faucet structure is adopted. At outer circumferences of
the respective edges 305d, 306d of the upper and lower core
supporting members 305, 306, for tightening the upper and lower
core supporting members 305, 306 to the cylindrical metal mold 304
with sufficient force, 1st oblique faces 305e, 306e are defined in
ring shape which are determined in angle to be within ranges of 5
to 30.degree., more preferably 5 to 20.degree. with respect to the
axially vertical direction of the metal mold.
[0321] The heating mechanism 307, 308 are divided into left and
right two parts, and are inside equipped with heat generators such
as cartridge heaters, hand heaters, high frequency induction
heaters and heating medium circulators, and the inner wall faces
thereof are contacted to the outer face of the cylindrical metal
mold 304 for heat transfer to the cylindrical metal mold 304.
Preferably, the radius of curvature of the inner wall faces of the
cylindrical metal mold 304 is set to be half or somewhat larger
than this half of the outer diameter 304, and a material quality of
the inner wall face preferably has substantially the same thermal
expansion coefficient as that of the cylindrical metal mold 304. At
both ends in the axial direction of the heating mechanisms 307,
308, pawl members 313, 314, 315, 316 are provided in a manner of
holding the edges 305d, 306d at the outer circumferences of the
core supporting members 305, 306 between left and right both sides,
and these pawl members 313, 314, 315, 316 are formed inside with
band-shaped 2nd oblique faces 313a, 314a, 315a, 316a. Besides, the
respective 2nd oblique faces 313a, 314a, 315a, 316a are pasted with
band-shaped heat resistant elastic members 309, 310, 311, 312, and
2nd oblique faces are forced to contact these heat resistant
elastic members to press the 1st oblique faces 305e, 306e. The pawl
members 313, 314, 315, 316 may be secured to the heating mechanism
main bodies by means of welding or bolt tightening, or moving
mechanisms (not shown) may be provided for sliding the pawl members
solely in the diameter direction.
[0322] A sequence for producing the roller by use of the above
mentioned injection forming apparatus will be explained in detail.
At first, the core body 303 is inserted inside the cylindrical
metal mold 304, both ends 303a, 303b are fitted into the core body
holding holes 305a, 306a defined in the core supporting members
305, 306, and these core supporting members 305, 306 are inserted
in both end parts of the cylindrical metal mold 304 so as to form
the roller forming space 317 inside of the injection forming metal
mold 302. Under this condition, the heating mechanisms 307, 308 are
moved from left and right both sides in a manner of holding the
injection forming metal mold 302 therebetween, to cause the 2nd
oblique faces 313a, 314a, 315a, 316a formed in the pawl members
313, 314, 315, 316 to contact the heat resistant elastic members
309, 310, 311, 312 so as to press the 1st oblique faces 305e, 306e,
so that the core supporting members 305, 306 are secured to the
cylindrical metal mold 304. By securing the heating mechanisms 307,
308, the upper and lower core supporting members 305, 306 are
firmly held at both edge faces 305d, 306d, and the injection
forming metal mold 302 is tightened and held. For firmly tightening
the cylindrical metal mold 304 to the core supporting members 305,
306, a tightening load of about 20 kgf or higher is ordinarily
necessary, and the invention can easily accomplish it.
[0323] Next, the lower core supporting member 306 is provided at
the resin injecting inlet 306 with the resin injecting nozzle (not
shown) for injecting and filling the resin material in the roller
forming space 317. The gas pressure then generated inside is
released by opening the gas venting hole 305b. After completing to
charge the resin material, the gas venting hole 305b is closed as
needed, and subsequently the roller forming space 317 is heated
around 60 to 150.degree. C. by the heat generators furnished in the
heating mechanisms 307, 308 for hot-setting the resin material. The
inner diameter of the gas venting hole 305b is preferably adjusted
to be 0.5 to 3.0 mm. Being less than 0.5 mm, the resin leaks due to
an inner high pressure to probably create burrs in products, while
being more than 3.0 mm, the resin invades in the gas venting hole
and widens an adhering area in the inner wall of the metal mold, so
that it is difficult to release products from the mold.
[0324] The injection forming metal mold 302 is cooled and released
under a condition where the heating mechanisms 307, 308 are moved
left and right in the diameter direction and is opened. Then, the
core supporting members 305, 306 are taken out, and after releasing
the roller as a product of the invention, the above mentioned
sequence is again repeated to produce new products.
[0325] At hot-setting, since the cylindrical metal mold 304 and the
upper and lower core supporting members 305, 306 are thermally
expanded, surface pressure becomes gradually higher between the 1st
oblique faces 305e, 306e formed in the upper and lower core
supporting members 305, 306 and the 2dn oblique faces 313a, 314a,
415a 316 formed in the respective pawl members 313, 314, 315, 316,
and the tightening load becomes larger between the cylindrical
metal mold 304 and the upper and lower core supporting members 305,
306, but in this embodiment, since the heat resistant elastic
members 309, 310, 311, 312 are interposed between the 1st oblique
faces 305e, 306e and the 2nd oblique faces 313a, 314a, 415a 316, an
increasing part of the tightening load generated by the thermal
expansion is absorbed thereby, so that excessive load is not added
to the core body 303, deformation as buckling is prevented and the
air tightness is heightened in the roller forming space, and the
roller formability is prevented from spoiling. The thickness of the
heat resistant elastic members 309, 310, 311, 312 is suitably 0.5
to 5.0 mm, and as the material quality having moderate elasticity
at said heating temperature of 60 to 150.degree. C., silicone or
fluoro-rubber are suited.
[0326] As the resin materials of the products, it is possible to
use the mixture of one or two kinds or more of the thermosetting
liquid resin such as epoxy resin, phenol resin, urea resin,
melamine resin, fran resin, unsaturated polyester resin, and
polyimide resin, or silicone based thermosetting liquid resin.
[0327] In the above embodiment, the resin injecting inlet 306b is
defined in the lower core supporting member 306, and the gas
venting hole 305 is defined in the upper core supporting member
305, and instead therefor, as schematically shown in FIG. 15, it is
sufficient to form a penetrating hole 318 in an upper core
supporting member 305' which serves as the resin injecting inlet
and the gas venting hole. Namely, when the resin injecting nozzle
319 is inserted in the penetrating hole 318, the resin material is
injected and filled in the roller forming space 317 under a
condition of providing a space for venting the gas between the
resin injecting nozzle 319 and the penetrating hole 318. If
adopting such a structure, the solidified resin material is less to
clog the resin injecting inlet, so that a merit is obtained which
makes the maintenance work of the forming device easier.
Embodiment 9
[0328] Explanation will be made another embodiment of the injection
forming apparatus according to he invention.
[0329] FIGS. 16 to 18 are schematically structured views showing
this embodiment. FIG. 16A is a plan view of this apparatus and FIG.
16B is a bottom view thereof. FIG. 17 is a schematically cross
sectional view showing the side view of the apparatus (B-B cross
sectional view of FIG. 16A). FIG. 18 is enlarged cross sectional
views of elementary parts of the apparatus.
[0330] The injection forming apparatus 321 of this embodiment is
composed of the cylindrical metal mold 324 inserted inside with a
core body 323, the injection forming metal mold 322 composed of the
core supporting members 325, 326 fitted inside to both edge parts
in the axial direction of the cylindrical metal mold 324 as holding
both edges 323a, 323b of the inside inserted core body 323, and the
heating mechanisms 327, 328 disposed around the injection forming
metal mold 322 and holding said metal mold 322 at both sides in the
diameter direction.
[0331] At the lower end of the core supporting member 325 and the
upper end of the core supporting member 326, fitting projections
325c, 326c are formed for fitting into both ends of the cylindrical
metal mold 324 similarly to the above embodiment 8, and the faucet
structure is adopted. At the upper and lower core supporting
members 325, 326, 1st brims 325f, 326f are expanded on the outer
circumferences respectively opposite to the cylindrical metal mold
324, while also at both ends of the cylindrical metal mold 324, 2nd
brims 324f, 324g are expanded in opposition to the 1st brims 325f,
326f. As shown in the enlarged cross sectional views in FIG. 18, at
the rear faces of the 1st brims 325f, 326f and the 2nd brims 324f,
324g, 1st oblique faces 325a, 326a and 324a, 324b are formed which
tilt at predetermined angles with respect to the axially vertical
direction. These tilting angles are preferably determined to be 5
to 300, especially 5 to 200 for tightening the upper and lower core
supporting members 325, 326 to the cylindrical metal mold 324 with
enough force.
[0332] On the other hand, the heating mechanisms 327, 328 are
formed in the inner wall faces with tapered grooves 330, 331 in
concave shape for engaging the 1st brims 325f, 326f and the 2nd
brims 324f, 324g in opposition under a closing condition.
[0333] In the upper and lower inner faces of these grooves 330,
331, 2nd oblique faces 330a, 330b, 331a, 331b are formed in half
ring shape, and are pasted with half ring shaped heat resistant
elastic members 332, 333, 334, 335. The 2nd oblique faces 330a,
330b, 331a, 331b are urged to press upward and downward on the heat
resistant elastic members 332, 333, 334, 335 so as to press the 1st
oblique faces 325a, 324a and 326a, 324b and tighten the core
supporting members 325, 326 and the cylindrical metal mold 324.
Other composing members are almost the same as those of the
embodiment 8, excepting the pawl members and the 1st oblique face,
and detailed explanation will be omitted.
[0334] A sequence for producing the roller by use of the above
mentioned injection forming apparatus will be explained in detail.
At first, the core body 303 is inserted inside the cylindrical
metal mold 324, both ends 323a, 323b are fitted into the core body
holding holes 325a, 326a defined in the core supporting members
325, 326, and these core supporting members 325, 326 are inserted
in both end parts of the cylindrical metal mold 324 and the
injection forming metal mold 322 is closed so as to form the roller
forming space 336. Under this condition, the heating mechanisms
327, 328 are moved from left and right both sides in the vertical
direction in a manner of holding the injection forming metal mold
322 therebetween, so that the brim parts 330, 331 are engaged with
the 1st brim parts 325f, 326f and the 2nd brim parts 234f, 324g,
and the 2nd oblique faces 330a, 330b, 331a, 331b are forced to
press upward and downward the heat resistant elastic members 332,
333, 334, 335 to press the 1st oblique faces 325a, 326a, 324a,
234b. By tightening the heating mechanism, the core supporting
members 325, 326 and the cylindrical metal mold 324 are tightened
and maintained.
[0335] By the same sequence as that of the embodiment 8, the roller
forming space 336 is injected and filled with the resin material,
the injection forming metal mold 322 is cooled, the heating
mechanisms 327, 328 are moved respectively left and right in the
axial direction to make an opening condition, and the injection
forming metal mold 322 is released. Subsequently, the core
supporting members 325, 326 are taken out, and after releasing the
roller as a product of the invention, the above mentioned sequence
is again repeated to produce new products.
[0336] In the above embodiments 8 and 9, the 1st oblique face and
the 2nd oblique face corresponding thereto are provided to both
ends of the metal mold, and in the invention, these faces may be
provided to one ends.
[0337] In the above embodiments 8 and 9, the injection forming
metal mold is a vertical type but the invention does not limit
thereto, a lateral type or a combination of a lateral type and a
vertical type are sufficient.
[0338] As mentioned above, according to the injection forming metal
mold of the roller for the electrophotography, the core supporting
member to be fitted in both ends of the cylindrical metal mold has
the 1st obliquity tilting at a fixed angle with respect to an axial
and vertical directions in the outer wall face, and the heating
mechanism has an inner wall face contacting to hold the injection
forming metal mold under a condition of closing the heating
mechanism and having the 2nd obliquity pressing the 1st obliquity
to the inner wall face, whereby the injection forming metal mold is
tightened and held, so that the structure of the metal mold is
simplified, and it is possible to largely automatize a series of
procedure from setting up of the injection forming metal mold to
the pouring, hot-setting, disassembling of the metal mold and
releasing of the product from the mold, which have been difficult
in the prior art.
[0339] Further, the heat resistant elastic member is interposed
between the 1st oblique face and the 2nd oblique face, so that the
increasing part of the tightening load generated by the thermal
expansion of the metal mold at hot-setting is absorbed by the heat
resistant elastic member, and stable tightening force of the metal
mold can be provided, and the roller formability can be
heightened.
Embodiment 10
[0340] Another embodiment of the invention will be explained,
referring to the drawings. As shown in FIG. 19A, the forming metal
mold 400 has the cylindrical metal mold 13 and a pair of core
supporting members 14a, 14b disposed at both ends of the
cylindrical metal mold 13, and the cylindrical metal mold 13 and
the pair of core supporting members 14a, 14b define the roller
forming space 15. One of the core supporting members 14b is
provided with the resin injecting inlet 16. In the inside of the
cylindrical metal mold 13, the core body 21 of the resin roller to
be formed is held at both ends in the core supporting holes 17a,
17b formed in both core supporting members 14a, 14b. The core
bodies 21 of the resin roller are, for example, as shown in FIGS.
22A to 22C. As materials of the core body 21, known arbitrary ones,
for example, metallic materials or resin materials rendered to be
conductive are applicable. As to sizes of the resin roller, not
different from those of the existing resin rollers, generally, the
diameter is 10 to 30 mm and the length is 200 to 400 mm.
[0341] The cylindrical metal mold 13 and the core supporting
members 14a, 14b are composed of known arbitrary materials for
thermosetting liquid resin, preferably pre-hardened steel, quenched
steel, non-magnetic steel, carbon tool steel, or corrosion
resistant steel (stainless steel). In the invention, ring like
concave grooves 430 are in advance formed at the opening edges of
the core supporting holes 17a, 17b of the core supporting members
14a, 14b for inserting the core body 21 therein, such that the core
supporting members 14a, 14b are, as the embodiment shown in FIG.
19, formed as the resin-formed edge faces stand in arc along the
core body 21 when forming, said ring like concave grooves 430
reducing the diameter in arc toward an inner part of the core
supporting holes 21 of larger diameter than the outer diameter of
the core supporting holes 21 supported by said core supporting
members 14a, 14b.
[0342] For forming the resin roller by means of the resin roller
forming injection forming 400, the core body 21 is inserted at both
ends in the core supporting holes 17a, 17a of the pair of core
supporting members 14a, 14b, and under a condition of previously
holding the core body 21 between both core supporting members 14a,
14b, the resin material is poured and filled from the resin
injecting inlet 16 into the roller forming space 15 formed by the
cylindrical metal mold 13 and the core supporting members 14a, 14b
of the cylindrical metal mold 13. The resin poured and filled in
the roller forming space 15 is also filled in the ring like grooves
430, 430 formed in the core supporting members 14a, 14b following
the periphery of the core body 21 at the axial both edge faces of
the forming space 15. After pouring and filling the resin material,
by hot setting the resin in the roller forming space 15, the
resin-formed body 12 is formed cylindrically around the core body
12. The edge face 12c of the cylindrical resin-formed body 12 is
formed as standing in the shapes of the ring like concave grooves
430 of the core supporting members 14, and standing parts 440 are
formed following the core body 21. After completion of solidifying
the resin, the core supporting members 14a, 14b are taken out
upward and downward from the cylindrical metal mold 13 in the axial
direction. Subsequently, the formed product held within the
cylindrical metal mold 13 is removed upward or downward in the
axial direction by doing as pushing the core 21 with respect to the
cylindrical metal mold 13. FIG. 19B shows the formed product of the
resin roller 10 taken out.
[0343] As the embodiment shown in FIG. 19, with respect to the
shape of the standing part 440 reducing the diameter in arc
following the end part of the core body 21, the radius of curvature
R of the arc in the outer face of the standing part reducing the
diameter is preferably formed to be 0.2 to 3 mm, and it is more
preferable that the radius of curvature R of the arc is formed to
be 0.5 to 2 mm, though depending on tolerance when the resin roller
10 is incorporated in an actual electro-photography. The standing
size L in the axial direction of the core body 21 from the edge
face 12c of the resin-formed body is preferably 0.5 to 5 mm, more
preferably 1 to 3 mm.
Embodiment 11
[0344] FIG. 20A shows a forming metal mold of another embodiment,
and FIG. 20B shows a shape of the formed product of the resin
roller 10 by use of this forming metal mold 400. This forming metal
mold 400 is formed with ring like concave grooves 430, 430 in the
core supporting members 14a, 14b in such shapes that the standing
parts 440 of the resin-formed body 12 linearly reduce the diameter
as going toward the ends of the core body 21. With respect to the
shape of the standing part 440 when forming the standing part to
linearly reduce the diameter toward the end part of the core 21 as
the edge face 12c of the resin-formed body follows the core body
21, the standing size L in the axial direction of the core body 21
from the edge face 12c of the resin-formed body is preferably 0.3
to 3 mm, more preferably 1 to 2 mm, though depending on tolerance
when the resin roller is incorporated in an actual
electrophotographic apparatus. The standing angle .theta. is
preferably 5 to 60.degree. on the basis of the axial direction in
the surface of the core body 21.
Embodiment 12
[0345] FIG. 21A shows a further embodiment, in which a forming
metal mold is to form stepwise standing parts 440 of the edge parts
12c of the resin-formed body, and FIG. 21B shows the shape of the
formed body of the resin roller obtained by the forming metal mold
400. As to the shape of the stepwise standing part 440, the
standing size L in the axial direction of the core body 21 from the
edge face 12c of the resin-formed body is preferably 0.3 to 3 mm,
more preferably 1 to 2 mm, though depending on tolerance when the
resin roller is incorporated in an actual electrophotographic
apparatus. The interface between the stepwise standing part 440 and
the edge face 12c of the resin formed body reduce the diameter in
arc. As to the thickness of the stepwise standing part 440, one
step is enough as shown, and also two steps or more are enough
gradually reducing the diameter. The sizes are as mentioned
above.
Embodiment 13
[0346] Further, as other embodiments, standing parts 440 shown in
FIGS. 23A to 23G can be adopted depending on conditions in
processing the core supporting members or allowed shapes in actual
machines. For example, if not permitting the stand of the formed
resin from the edge part 12c of the resin-formed body to the edge
part of the core body 21 in dependence on sizes of the
electrophotographic apparatus, it is possible, for example, as
shown in FIGS. 23F and 23G, to design in ring like concave shape
the circumference of the core body 21 of the edge face 12c of the
resin-formed body, and form the standing part 440 in the concave
part 450. The sizes of the standing parts 440 shown in FIGS. 23A to
23G are the same as those of the embodiments shown in FIGS. 19 to
21.
[0347] One example of the actually forming method of the inventive
resin roller will be explained. For example, polysiloxane based
hardening agent and the conductivity giving agent (carbon black)
are mixed in terminal allylated polyoxy propylene based polymer,
and when the roller is formed of the outer diameter being .phi.16
mm and the length of the resin-formed body being 250 mm in the
liquid resin injecting and pouring machine, the viscosity of the
mixed and poured resin is 200 to 5000 poises through depending on
the number of mixing parts of the conductivity giving agent, and
the pouring pressure is 0.5 to 15 MPa. When, for example, the
thickness of the resin-formed body is 4 mm in the roller of the
above sizes, the diameter of the resin injecting inlet is 1 to 2
mm. The metal mold stands vertically in the lengthwise direction,
and preferably the resin is poured from the lower part of the metal
mold.
[0348] The metal mold is heated by the existing arbitrary methods.
For example, there are a heating method within the heating oven
furnished with heating fans, a method of heating by arranging
electric heaters around the metal mold, or a method of arranging
the induction heating coils around the metal mold. For temperatures
of the metal mold, optional temperatures can be selected, enabling
to pour the thermosetting liquid resin and hot-set the resin, and
when pouring the resin, temperatures easily pouring the resin and
not solidifying it are preferable, for example, 20 to 70.degree. C.
Further, the resin heating temperature is desirably around 80 to
200.degree. C., though depending on the amount of hardening
retardant.
[0349] As roller forming resin materials available to the inventive
forming method, resins of heat-removal hardening are employed, for
example, silicone, polyurethane, acrylonitrile.butadiene copolymer
(NBR), ethylene.propylene.diene.methylen copolymer (EPDM). The
thermosetting liquid resin may be added with other kinds of
additives as needed. For example, if a resistance controlling agent
as carbon is added, electric resistance of the roller can be
controlled.
[0350] One of the preferable embodiments of the invention is to use
the thermosetting liquid resin containing, as main components, (A)
polymer containing at least one alkenyl group in molecule and a
repeating unit composing a main chain being mainly oxy alkylene
unit or saturated hydrocarbon unit, (B) a hardening agent
containing at least two hydrosilyl group in molecule, (C) catalyst
made hydrosilyl, and (D) conductivity giving agent. Since the
forming resin comprising the reaction hardened substance of the
hardening composition has especially soft structure, it displays
enough elastic effect even if the thickness is thin. When
containing oxy alkylene unit, the resin is low in viscosity before
hardening and easily handled, and on the other hand, when
containing saturated hydrocarbon unit, the resin has the low
absorption coefficient, and is desirable because the volume and the
roller resistance are less to change.
[0351] The thermosetting liquid resin is added, if necessary, with
materials for adjusting thermosetting reaction such as hardening
agent, hardening accelerator, hardening retardant or others. Or,
organic or inorganic fillers may be added. Further, some kinds of
organic or inorganic pigments, thickener or mold releasing agent
may be added.
[0352] In the following, explanation will be made to embodiments of
the invention, but the embodiments do not limit the invention.
[0353] The resin roller 10 of the roller outer diameter being
.phi.16 mm and the length of a resin formed body 12 being 250 mm as
shown in FIG. 19B was formed by use of the metal mold 400 shown in
FIG. 19A. The core supporting members 14a, 14b of the forming metal
mold 400 are defined with the ring-like concave grooves 430, 430
such that the outer diameter d of the core body 21 is 8 mm, the
shape of the standing part 440 at the edge face 12c of the
resin-formed body has the radius of curvature R being 2 mm, and the
standing size L of the core body 21 toward the axial direction is
2.5 mm.
[0354] The used thermosetting liquid resin was 600 poises in the
viscosity in the mixed resin shown in the table 1.
[0355] In the liquid resin injecting and pouring machine, the mixed
resin material was poured into the metal mold having the resin
injecting inlet 16 of 1.5 mm from the lower portion under the
pouring pressure of 4 MPa, the metal mold standing vertically in
the lengthwise direction. The metal mold was arranged within the
heating oven provided with the heating fans and was heated by
setting the atmospheric temperature within the heating oven to be
140.degree. C. for 20 minutes and releasing from the metal mold as
exerting the leasing load of 20 kg in the axial direction from the
metal mold, and a formed product was obtained. As a result, at the
ends of the obtained roller, no resin leakage occurred.
[0356] In the resin roll and the forming metal mold of the
invention, the edge face of the resin-formed body stands along the
core body, and since force concentrating in the standing portion
when releasing the mold after forming is dispersed, the
resin-formed body and the core body do not separate, and good
products are available cheaply and stably.
INDUSTRIAL APPLICABILITY
[0357] The resin roller, the resin roller producing apparatus and
the method of producing the same are suited to developing roller,
charging roller, transcribing roller and others.
* * * * *