U.S. patent number 3,875,581 [Application Number 05/373,892] was granted by the patent office on 1975-04-01 for developing device for copying apparatus of the diazo type.
This patent grant is currently assigned to Ricoh Co., Ltd.. Invention is credited to Yasuhiro Takahashi, Tadashi Yamashita.
United States Patent |
3,875,581 |
Yamashita , et al. |
April 1, 1975 |
Developing device for copying apparatus of the diazo type
Abstract
A device comprising a developing liquid quantity control member
operatively associated with a developing liquid supply roller for
adjusting to an optimum level the quantity of a nonvolatile,
concentrated developing liquid supplied to a developing position
between a developing liquid applicator roller and a pressure
applying roller so as to apply an essential minimum of the
developing liquid to an exposed photosensitive sheet of the diazo
type fed to the developing position. There is also provided a
developing liquid removal member disposed posteriorly to the
developing position for removing from the periphery of the
developing liquid applicator roller any excess developing liquid
which might otherwise remain thereon.
Inventors: |
Yamashita; Tadashi (Yokohama,
JA), Takahashi; Yasuhiro (Tokyo, JA) |
Assignee: |
Ricoh Co., Ltd. (Tokyo,
JA)
|
Family
ID: |
13450474 |
Appl.
No.: |
05/373,892 |
Filed: |
June 26, 1973 |
Foreign Application Priority Data
|
|
|
|
|
Jul 15, 1972 [JA] |
|
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47-71090 |
|
Current U.S.
Class: |
396/607; 118/203;
118/249; 118/262; 399/284; 396/606; 399/237 |
Current CPC
Class: |
G03D
5/067 (20130101) |
Current International
Class: |
G03D
5/00 (20060101); G03D 5/06 (20060101); G03d
005/00 () |
Field of
Search: |
;95/89R,89A,89G ;355/10
;118/203,249,250,262 ;354/297,300,317,318,319 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
Primary Examiner: Braun; Fred L.
Attorney, Agent or Firm: Cooper, Dunham, Clark, Griffin
& Moran
Claims
What is claimed is:
1. A developing device for copying apparatus of the diazo type
comprising:
a. an rotating applicator roller having a peripheral surface for
applying a non-volatile concentrated developing liquid to a diazo
photosensitive sheet exposed to an optical image of an original to
be duplicated;
b. a supply roller having a peripheral surface maintained in
pressing engagement with said peripheral surface of the applicator
roller to form therebetween an engaging position and rotating at
approximately the same peripheral velocity as said applicator
roller for supplying the developing liquid to the applicator
roller;
c. a control member maintained in pressing engagement with said
peripheral surface of the supply roller in a position disposed
anterior to the engaging position of said surfaces of the
applicator and supply rollers along their paths of rotation for
adjusting the quantity of the developing liquid supplied to the
applicator roller;
d. a pressing member maintained in pressing engagement with said
applicator roller to form therebetween a developing position
through which a diazo photosensitive sheet passes to be developed;
and
e. a removal member maintained in pressing engagement with said
peripheral surface of the applicator roller in a position disposed
posterior to the developing position along its path of rotation so
as to remove any excess developing liquid from the applicator
roller after a developing operation is performed and before any
further developing liquid is supplied thereto.
2. A device according to claim 1 wherein said control member and
said removal member are both doctor blades.
3. A device according to claim 1 wherein said control member is a
squeeze roller, and said removal member is a doctor blade.
4. A device according to claim 1 wherein said control member is a
doctor blade, and said removal member is a roller.
5. A device according to claim 1 wherein said applicator roller is
of a rubber material having a hardness in a range from 40.degree.
to 70.degree. and a mean surface coarseness of less than
3.mu.Ra.
6. A device according to claim 1 wherein said supply roller is of
rubber material having a hardness in a range form 40.degree. to
60.degree. and the average surface coarseness is in a range between
3 and 4.mu.Ra.
7. A device according to claim 1 further comprising operating means
for releasing said pressing member, said applicator roller and said
supply roller from pressing engagement with one another and
releasing said control member and said removal member from pressing
engagement with said supply roller and said applicator roller
respectively when the developing device is rendered inoperative,
and for bringing said pressing member, said applicator roller and
said supply roller into pressing engagement with one another said
control member and said removal member into pressing engagement
with said supply roller and said applicator roller respectively
when the developing device is rendered operative.
8. A device according to claim 7 wherein said pressing member
comprises a pressing roller whose axis lies on a line with the axes
of said applicator roller and said supply roller, and said
operating means comprises a lever means having a pressure roller on
one end for engaging said pressing roller, and pivotable for
pressing said pressure roller against said pressing roller to bring
said pressing, applicator, and supply rollers into pressing
engagement with each other, first mounting means for said removal
member, second mounting means for said control member, two
rotatably cooperating segmental gears respectively mounting said
first and second mounting means and respectively disposed adjacent
said applicator roller and siad supply roller such that upon
rotation of said two segmental gears, said removal and control
members will be respectively brought into pressing engagement
therewith, crank means operatively coupled at one end to said two
segmental gears for rotating said gears and operatively coupled at
the other end to said lever means for transmitting the pivoting of
said lever means into rotation of said two segmental gears, and
actuation means for pivoting said lever means whereby said pressing
roller, said applicator roller, and said supply roller are brought
into pressing engagement with one another and said control member
and said removal member are brought into pressing engagement with
said supply roller and said applicator roller respectively.
9. A device according to claim 8 wherein said actuation means
comprises a solenoid having an actuator, and toggle-linkage means
connected to said actuator for pivoting said lever means upon the
actuation of said solenoid.
10. A device according to claim 8 wherein said actuation means
comprises a solenoid having an actuator, and an hydraulic
transmission means for pivoting said lever means upon the actuation
of said solenoid.
11. A device according to claim 8 wherein said crank means
comprises two links pivotally connected at one end to each other
and each connected at its other end respectively to said lever
means and one of said two segmental gears.
12. A device according to claim 8 wherein said crank means
comprises two links each connected at one end to said lever means
and at the other end respectively to one of said two segmental
gears.
Description
BACKGROUND OF THE INVENTION
This invention relates to developing devices for copying apparatus
of the diazo type, and more particularly it is concerned with a
developing device of the type described whereby a diazo
photosensitive sheet of the binary system exposed to an optical
image of an original is developed by applying a very small quantity
of a developing agent consisting of an organic amine and other
elements.
In addition to a dry developing agent and liquid developing agent,
a developing liquid consisting of an organic amine and other
elements and usually in the form of a nonvolatile, concentrated
developing liquid is used to develop optical images of originals
formed by exposure on diazo photosensitive sheets. The use of this
type of developing liquid is advantageous in that the optical
images can be developed by applying a very small quantity of the
developing liquid so that the photosensitive sheets are dry when
the images thereon are developed in spite of the fact that the
developing liquid is used. A developing system using this type of
developing liquid is described, for example, in Japanese Pat. Pub.
No. Sho 44-24998.
The quantity of the developing liquid required in this developing
system for developing optical images formed on diazo photosensitive
sheets is only 60 to 150 mg., when the sheets are of a particular
size, which is about one tenth the quantity of the developing
liquid required in conventional developing systems using a liquid
developing agent. The paucity of the developing liquid required for
performing this developing operation permits the photosensitive
sheets to be in a dry state after developing as if a dry developing
agent were used.
In carrying out development by this developing system, it is
essential that the very small quantity of the developing liquid
used be uniformly applied to the photosensitive surface of the
photosensitive sheet in order to achieve satisfactory result. If
the developing liquid is not evenly applied to the photosensitive
surface of the photosensitive sheet, the photosensitive sheet may
show a change in color with time. Since the developing liquid is
applied to the photosensitive surface only, if the quantity of the
developing agent applied to the photosensitive surface is larger
than is necessary, the photosensitive sheet may curl up with the
photosensitive surface facing inwardly when developed, so that the
photosensitive sheet may not be of any practical value.
Difficulty has hitherto been experienced in this developing system
in applying a very small quantity of the developing liquid evenly
on a photosensitive sheet to form a layer of the developing liquid
of a uniform thickness. It has hitherto been customary to form a
layer of the developing liquid of a uniform thickness on an
applicator roller by some means and to bring the exposed
photosensitive surface of a diazo photosensitive sheet into
pressing engagement therewith so as to develop the image on the
photosensitive surface.
In forming a layer of the developing liquid on an applicator
roller, it has hitherto been customary to use a roller for
adjusting the thickness of the layer to any level as desired or to
use a doctor blade for forming a layer of a uniform thickness. The
use of the roller or doctor blade has problems which are hard to
obviate. More specifically, the use of the roller has the problem
of how to preclude deflection of the roller or to improve the
degree of precision with which the roller is made. The peripheral
velocity of the roller is also a factor influencing the quantity of
the developing liquid applied to the applicator roller. The method
of using a doctor blade for forming a coat of the developing agent
of a uniform thickness makes it necessary to fabricate the front
end of the doctor blade with a considerably high degree of
precision. Besides, the manner of application of the doctor blade
to the applicator roller and the degree of coarseness of the
surface of the applicator roller tend to affect the adjusments of
the quantity of developing liquid applied to the applicator roller.
Frictional dragging of the doctor blade on the applicator roller
tends to cause wear and damage thereto, sometimes resulting in the
applicator roller oscillating in small amplitude. By and large, the
use of a doctor blade for adjusting the quantity of the developing
liquid on the applicator roller is more advantageous than the use
of a roller for forming a layer of the developing liquid of a
uniform thickness on the applicator roller in that the operation is
less affected by speed and can be performed by using a lower
pressure at which it is maintained in engagement with the
applicator roller.
SUMMARY OF THE INVENTION
This invention has as its object the provision of a developing
device for copying apparatus of the diazo type using a developing
liquid of high efficiency consisting of an organic amine and other
elements which device comprises a developing liquid quantity
control member operatively associated with a developing liquid
supply roller having a relatively coarse peripheral surface for
adjusting the quantity of the developing liquid supplied to a
developing liquid applicator roller maintained in pressing contact
with the developing liquid supply roller to an optimum level so as
to form on the periphery of the latter a layer of the developing
liquid of a uniform thickness which is insusceptible to changes in
the peripheral velocity of the developing liquid applicator
roller.
According to the invention, there is provided a developing device
for copying apparatus of the diazo type comprising a developing
liquid quantity control member operatively associated with a
developing liquid supply roller for adjusting to an optimum level
the quantity of a nonvolatile, concentrated developing liquid
supplied to a developing position between a developing liquid
applicator roller and a pressure applying roller so as to apply an
essential minimum of the developing liquid to an exposed
photosensitive sheet of the diazo type fed to the developing
position. There is also provided a developing liquid removal member
disposed posterior to the developing position for removing from the
periphery of the developing liquid applicator roller any excess
developing liquid which might otherwise remain thereon. The
invention is effective to form on the periphery of the developing
liquid applicator roller a layer of the developing liquid of a
uniform thickness at all times so that the features of the
nonvolatile, concentrated developing liquid can be brought into
full play.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a sectional view of the developing device for copying
apparatus of the diazo type comprising one embodiment of the
present invention;
FIG. 2 and FIG 3 are sectional views of the developing device for
copying apparatus of the diazo type comprising second and third
embodiments of the invention respectively;
FIG. 4 is a diagram showing curves representing the quantities of
the developing liquid applied to the photosensitive sheets as a
body function of supply roller speed using different embodiments of
developing device;
FIG. 5 to FIG. 8 are diagrams showning curves representing the
quantities of the developing liquid applied to the photosensitive
sheets as a function of applicator roller speed; and
FIG. 9 to FIG. 11 are sectional side views of different types of
mechanism in concrete form for operating the device according to
the invention.
DESCRIPTION OF PREFERRED EMBODIMENTS
FIG. 1 shows one embodiment of the developing device according to
the invention. A liquid supply roller 1, which is adapted to be
rotated in the direction of an arrow a by a drive (not shown), is
made of a non-porous material or rubber of 40.degree.to 60.degree.
of hardness and an average surface coarseness of 3 to 5 .mu.Ra. The
developing liquid supply roller 1 has a lower portion of its
periphery immersed in a nonvolatile, concentrated developing liquid
3 contained in a developing pan 2 and is maintained at an upper
portion of its periphery in pressing engagement with a developing
liquid applicator roller 4 adapted to rotate in the direction of an
arrow b.
A developing liquid quantity control member 5 or a first doctor
blade is maintained in engagement with the periphery of the
developing liquid supply roller 1 in a position which is disposed
anterior to or leftwardly in FIG. 1 of the position in which the
developing liquid applicator roller 4 is maintained in pressing
engagement with the supply roller 1. The developing liquid quantity
control member 5 is constructed such that the angle at which it is
disposed with respect to the periphery of the developing liquid
supply roller 1 and the degree at which it is maintained in
pressing engagement with the periphery of the supply roller 1 can
be varied so as to thereby adjust to an optimum level the quantity
of the developing liquid scooped up by the supply roller 1 and
supplied to the applicator roller 4. Thus the quantity control
member 5 is disposed above the liquid level in the developing
liquid pan 2.
The developing liquid supply roller 1 is shown and described as
having the lower portion of its periphery being immersed in the
developing liquid 3 in this embodiment. This is not essential,
however, and the developing liquid can be supplied to the supply
roller either by spraying or other means.
The developing liquid scooped up by the supply roller 1 is supplied
to a developing position 7 disposed between a pressing roller 6 and
the applicator roller 4 maintained in pressing engagement with each
other. The pressing roller 6 is in the form of a metallic roller
made as of stainless steel in this embodiment and rotates in the
direction of an arrow c. Preferably, a series of peripheral grooves
or a spiral groove disposed peripherally of the roller is formed in
the roller 4 so as to prevent the developing liquid from being
collected between the two rollers 1 and 4. In the developing
position 7, the pressing roller 6 is maintained in line or surface
engagement with the applicator roller 4, and an exposed
photosensitive sheet 8 is fed to the developing position 7 from
right to left in FIG. 1.
A developing liquid removal member 9 or a second doctor blade is
disposed posterior to the developing position 7 in which the
pressing roller 6 is in engagement with the applicator roller 4. It
is maintained at its forward end in pressing engagement with the
periphery of the applicator roller 4 so as to remove therefrom any
excess developing liquid which might otherwise remain thereon. Like
the quantity control member 5, the developing liquid removal member
9 is constructed such that the angle at which it is disposed with
respect to the periphery of the applicator roller 4 and the degree
at which it is maintained in pressing engagement with the periphery
of the applicator roller 4 can be varied as desired.
The developing liquid removal member 9 and the quantity control
member 5 each have a length which is slightly greater that the
width of the periphery of the supply roller 1 and the applicator
roller 4. The reason why the developing liquid removal member 9 is
disposed posterior to the developing position 7 is because the
layer of the developing liquid on the portion of the periphery of
the applicator roller 4 disposed anterior to the developing
position 7 has an optimum thickness by virtue of the presence of
the quantity control member 5. It is to be understood that the
position in which the removal member 9 is disposed may be nearer to
the developing position 7 than is shown in FIG. 1. However, the
position in which the removal member 9 is shown as being disposed
in FIG. 1 is a most convenient one from the point of view of
removing the developing liquid when the length of the member 9,
means for adjustably fixing the same and the peripheral velocity of
the applicator roller 4 are taken into consideration.
The developing device constructed as aforementioned is advantageous
in supplying the developing liquid from the supply roller 1 to the
applicator roller 4. The physical properties of the developing
liquid will show variations due to changes in the peripheral
velocity of the rollers and the environmental conditions including
temperature. That is, the viscosity of the developing liquid will
vary depending on temperature, and the quantity of the developing
liquid scooped up by the supply roller will vary depending on a
change in the peripheral velocity of the roller. This is clearly
shown by the results of tests. More specifically, curves shown in
the diagram in FIG. 4 represent the quantities of the developing
liquid applied to the photosensitive sheets obtained by plotting
the quantities of the developing liquid as the ordinates against
the peripheral velocities of the supply roller as the abscissae.
The broken line A represents the quantity of the developing liquid
which is adjusted only by using a doctor blade as a developing
liquid quantity control member and transferring the developing
liquid directly from the supply roller to the photosensitive sheet.
It will be seen that the quantity increases substantially in
proportion to the peripheral velocity of the supply roller. The
dash-and-dot line B represents the quantity of the developing
liquid which is adjusted only by transferring the developing liquid
from the supply roller to the applicator roller without the use of
a doctor blade. It will be seen that in this case the quantity is
reduced because the time during which the developing liquid is
transferred to the applicator roller becomes shorter as the
peripheral velocity of the supply roller increases. Thus, by
suitably combining the aforementioned two control methods with each
other, it will be possible to supply the developing liquid in
uniform quantity as shown by the solid line C irrespective of
changes in the peripheral velocity of the supply roller. This
invention is based on the aforementioned concept.
Generally, an increase in the peripheral velocity of the developing
liquid supply roller 1 results in an increase in the quantity of
the developing liquid supplied from the supply roller 1 after being
adjusted by the control member 5. Therefore, if the photosensitive
sheet 8 is moved between the rollers 1 and 4 in a position disposed
immediately posterior to the position in which the control member 5
is maintained in engagement with the supply roller 1, the
developing liquid will be applied in a large quantity to the
photosensitive sheet. However, if the photosensitive sheet 8 is
brought into contact with the applicator roller 4 after the
developing liquid is transferred from the supply roller 1 to the
applicator roller 4 after being adjusted by the control member 5,
the quantity of the developing liquid applied to the photosensitive
sheet will be reduced when the peripheral velocity of the supply
roller increases because the quantity transferred to the applicator
roller 4 is reduced and will be increased when the peripheral
velocity of the supply roller decreases because the quantity
transferred to the applicator roller is increased.
Because of this, it is possible to apply the developing liquid in a
substantially uniform quantity to the photosensitive sheet 8 by
causing the latter to move through the developing position 7
between the applicator roller 4 and the pressing member 6
irrespective of changes in the peripheral velocity of the supply
roller 1.
By varying the pressure at which the rollers 1 and 4 are maintained
in pressing engagement with each other, it is possible to control
to a certain extent the quantity of the developing liquid
transferred from the supply roller 1 to the applicator roller 4. It
is thus possible to form on the periphery of the applicator roller
4 a layer of the developing liquid of a substantially uniform
thickness at all times. Preferably, the applicator roller 4 is made
of a non-porous material which suits photosensitive sheets. The
material used for making the applicator roller 4 in this embodiment
is rubber having a hardness in a range from 40.degree. to
70.degree. (preferably from 40.degree. to 50.degree.) and a mean
surface coarseness of less than 3 .mu.Ra (preferably between 1 and
1.5 .mu.Ra). When the periphery of the applicator roller 4 has a
mean coarseness of above 3 .mu.Ra, the coarseness of the roller
unfavorably affects the photosensitive sheets and lowers the
quality of the duplicates produced.
The developing liquid on the applicator roller 4 can be applied by
pressure transfer in a quantity which is an essential minimum to
the photosensitive sheet fed to the developing position 7 in which
the pressing roller 6 is maintained in line or surface engagement
with the applicator roller 4.
When no photosensitive sheet is fed to the developing position, any
excess developing liquid on the applicator roller 4 is removed
therefrom by the removal member 9. Thus, when the developing device
is set in motion, the developing liquid is continuously supplied
from the supply roller 1 to the applicator roller 4. If no removal
member 9 were provided, the developing liquid supplied and retained
on the applicator roller 4 would become so great in quantity that
it would saturate the periphery of the applicator roller 4 and no
more developing liquid would be supplied from the supply roller 1
to the applicator roller 4. If a photosensitive sheet were fed to
the developing position 7 at this time, more developing liquid than
is necessary would be applied to the photosensitive sheet by the
applicator roller 4, so that the duplicate produced would be
degraded in quality. In order to avoid such phenomenon, the removal
member 9 is essential to remove excess developing liquid from the
applicator roller 4 and return it to the developing pan 2. The
removal member 9 and adjusting member 5 are preferably made of a
resilient material and covered with a material of low coefficient
of friction, such as Teflon, for example.
The supply roller 1 may be rotated at the same peripheral velocity
as the applicator roller 4. The developing liquid can be supplied
satisfactorily to the applicator roller 4 to form a layer of
developing liquid of a uniform thickness thereon even if the
peripheral velocity of the supply roller 1 is slightly lower than
that of the applicator roller 4.
FIG. 2 and FIG. 3 shown modified forms of the developing device
according to the invention. In the embodiment shown in FIG. 2, the
developing liquid quantity control member 5 is in the form of a
squeeze roller 5a, with the rollers 1, 5a, 4 and 6 being maintained
in pressing engagement with one another. The developing liquid
scooped up by the supply roller 1 is transferred to the squeeze
roller 5a where the quantity of the developing liquid is adjusted
to an optimum level before being transferred to the applicator
roller 4. The transfer of the developing liquid from roller to
roller is carried out continuously while the rollers rotate. For
practical purposes, the squeeze roller 5a is required to be
fabricated with a considerably high degree of precision. The
developing position is disposed between the applicator roller 4 and
the pressing roller 6 in this embodiment too. In the embodiment
shown in FIG. 3, a roller 9a is substituted for the doctor blade 9
of FIG. 1 as a developing liquid removal member 9.
FIG. 5 to FIG. 8 show the results of experiments carried out on the
quantity of the developing liquid applied to the photosensitive
sheet 8 by the applicator roller 4 as a function of the peripheral
velocity of the applicator roller. A line D in FIG. 5 represents
the weight of developing liquid transferred to an overlying sheet
of two photosensitive sheets superposed one on the other and fed
between the rollers 1 and 4. A line E in FIG. 6 represents the
quantity of the developing liquid remaining on the applicator
roller 4. A line F in FIG. 7 shows the rate of transfer of the
developing liquid from the supply roller 1 to the applicator roller
4. A line G in FIG. 8 represents the quantity of the developing
liquid on the supply roller 1.
From the data shown in the figures, it will be seen that changes in
the quantity of the developing liquid are very small and the
transfer of the developing liquid from the supply roller 1 to the
applicator roller 4 can achieve satisfactory results in forming a
layer of the developing liquid of a uniform thickness on the
latter, although no definitive relation is established between the
peripheral velocity of the supply roller and the quantity of the
developing liquid applied to the photosensitive sheet because of
the fact that the efficiency of the doctor blade 5 is higher than
expected.
In order to prevent deformation of the supply roller 1 and the
applicator roller 4, the control member 5 and the removal member 9
are preferably released from engagement with the rollers 1 and 4
respectively or maintained in light engagement therewith when the
developing device is out of service. The rollers 6, 5a and 1 are
preferably released from pressing engagement with one another when
the developing device is out of service. The pressure at which the
removal member 9 is in engagement with the applicator roller 4 is
preferably the same as or higher than the pressure at which the
control member 5 is in engagement with supply roller 1.
Accordingly, the developing device according to the invention is
operated by a mechanism which comprises a solenoid adapted to be
energized when a start switch (not shown) is turned on so that the
rollers may be brought into pressing engagement with one another
and the control and removal members may be brought into pressing
engagement at their front ends with the respective rollers. Such
mechanism will now be described with reference to embodiments shown
in FIG. 9 to FIG. 11.
The embodiment shown in FIG. 9 utilizes a togglejoint and is
constructed such that upon energization of the solenoid SOL a link
11 is pivoted counter clockwise at one end about an immovably pin
12 and the other link 13 is guided by another immovable pin 14
received in a slot 13a formed in the link 13, so that a pressure
applying arm 15 is moved upwardly.
More specifically, the solenoid SOL has connected thereto an
actuator SOLo which is pulled by the solenoid SOL upon energization
thereof and which has a pin 16 riding in a transverse slot 16a
therein and supporting the link 11 at the end opposite that which
is pivotally supported by the immovable pin 12 as aforementioned.
The pin 16 also supports the link 13 at one end which is
symmetrically arranged with respect to the link 11, the link 13
being formed at the other end portion with the slot 13a for
receiving therein the immovable pin 14 as aforementioned.
By the aforementioned arrangement, the link 11 will pivot counter
clockwise in FIG. 9 about the pin 12 when the actuator SOLo is
pulled toward the solenoid SOL, so that the pin 16 will move along
an arc leftwardly in FIG. 9 and the link 13 will move upwardly as
guided by the pin 14 received in the slot 13a. The link 13 moves by
its upper end the pressure applying arm 15 upwardly. The pressure
applying arm 15 is pivotally supported by a pressure applying
roller shaft 17 and includes a free end portion 15a extending above
the upper end of the link 13 and moved downwardly about shaft 17 by
the biasing force of a spring 18, so that a bent portion 15b formed
on the free end portion 15a is maintained in contact with the upper
end of the link 13. The pressure applying arm 15 has firmly secured
to an end portion thereof which is disposed at the opposite end
from the free end portion 15a a pressure applying roller supporting
member 19 supporting a pressure applying roller 20. The pressure
applying roller 20 is adapted to bear against the pressing roller 6
so as to bring the roller 6 into pressing engagement with the
applicator roller 4 and to bring the roller 4 into pressing
engagement with the supply roller 1 when the link 13 moves the
pressure applying arm 15 upwardly.
On the other hand, a bar 21 extending toward the rollers is
connected at one end 21a to the free end portion 15a of the
pressure applying arm 15 through a pin 22 and supports at the other
end 21b one end of connector 23 through a pin 24, the connector 23
being firmly secured at the other end to a rotary shaft 25. The
rotary shaft 25 has secured thereto a segmental gear 26 which in
turn has secured thereto a blade mounting member 27. The developing
liquid removal member 9 in the form of a doctor blade is secured at
its base to the mounting member 27 and has a forward end which is
disposed near the periphery of the applicator roller 4 and which is
adapted to be brought into pressing engagement with the periphery
of the applicator roller 4 when the segmental gear 26 pivots
counterclockwise about the shaft 25 which angularly rotates in the
same direction as the segmental gear 26.
The segmental gear 26 is maintained in meshing engagement with
another segmental gear 28 pivotally supported by a shaft 29 and has
a mounting member 30 secured thereto. The developing liquid
quantity control member 5 in the form of a doctor blade is secured
at its base to the mounting member 30 and has a forward end which
is disposed near the periphery of the supply roller 1 and which is
adapted to be brought into pressing engagement with the periphery
of the supply roller 1 when the segmental gear 28 pivots clockwise
about the shaft 29.
Operation of the embodiment constructed as aforementioned will now
be described. Upon energization of the solenoid SOL the actuator
SOLo is pulled toward the solenoid SOL and moves leftwardly in FIG.
9, so that the link 11 pivots counterclockwise about the pin 12
under the action of pin 16. This causes the pin 16 to move in an
arc leftwardly and push the link 13 so that the latter moves
upwardly while being guided by the pin 14 received in the slot 13a.
This causes the front end edge of the link 13 to push and move the
bent portion 15b of the pressure applying arm 15, so that the arm
15 pivots clockwise about the pressure applying roller shaft 17.
This causes the pressure applying roller 20 to push the pressing
member 6 downwardly, so that the pressing member 6 bears against
the applicator roller 4 and the applicator roller 4 bears against
the supply roller 1.
On the other hand, clockwise pivoting of the pressure applying arm
15 also causes, through the bar 21, the connector 23 to pivot
counterclockwise about the shaft 25 which angularly rotates about
its own axis. Counterclockwise pivoting of the connector 23 causes
the segmental gear 26 to pivot counterclockwise about the shaft 25
which angularly moves in the same direction as the segmental gear
26, so that the front end of the removal member 9 is brought into
pressing engagement with the periphery of the applicator roller 4.
Counter clockwise pivoting of the segmental gear 26 causes the
segmental gear 28 in meshing engagement with the segmental gear 26
to pivot clockwise about the shaft 29 so as to bring the front end
of the control member 5 into pressing engagement with the periphery
of the supply roller 1.
The embodiment shown in FIG. 10 employs a hydraulic pressure
cylinder and piston arrangement in place of the toggle-joint for
causing the pressure applying arm 15 to pivot. More specifically,
the actuator connected to and pulled by the solenoid SOL is in the
form of an arm 31 which is supported at a base 31a by an immovable
member 32 through a pin 33 and connected at its front end 31b to
the solenoid SOL. Connected to the arm 31 between the opposite ends
thereof is a piston rod supporting at its end a piston 34 received
in a cylinder 35 for compressing the fluid contained therein.
Another cylinder 37 is disposed below the bent portion 15b of the
pressure applying arm 15 which is adapted to be pushed and moved
upwardly by a piston rod supporting at its end a piston 36 received
in the cylinder 37 for compressing the fluid contained therein. The
cylinders 35 and 37 are maintained in communication with each other
through a pipe 38. Other parts of the mechanism are substantially
similar to the corresponding parts of the mechanism shown in FIG. 9
except for the arrangement in which the connector 23 and the
pressure applying arm 15 are connected to each other by a
compression spring 39 and the pin 24 planted on the connector 23 is
adapted to be pushed and moved by an arm 15c projecting from the
lower edge of the pressure applying arm 15.
Upon energization of the solenoid SOL the front end 31b of the arm
31 is pulled toward the solenoid SOL and the arm 31 pivots
clockwise about the pin 33, so that the piston 34 moves rightwardly
in FIG. 10 and compresses the fluid in the pipe 38. This pushes and
moves the piston 36 in the cylinder 37 upwardly, so that the
pressure applying arm 15 pivots clockwise in FIG. 10 about the
pressure applying roller shaft 17. Operation of the mechanism
thereafter is substantially similar to operation of the mechanism
shown in FIG. 9, so that the description thereof will be omitted,
although the parts similar in function to the parts shown in FIG. 9
are designated by like reference characters.
FIG. 11 shows another embodiment of the mechanism in which the
segmental gears 26 and 28 employed in the two embodiments shown in
FIG. 9 and FIG. 10 are replaced by a linkage. More specifically,
the segmental gears 26 and 28 are replaced by links 40 and 41 and
the blade mounting member 27 is directly fixed to the link 40 while
the blade mounting member 30 is directly fixed to the link 41, with
the control member 5 and the removal member 9 being supported by
the blade mounting members 27 and 30 respectively.
The link 40 has a free end portion 40a which is connected by a
connector 42 to one arm portion 15a of the pressure applying arm
15. More specifically, the free end portion 40a is supported by the
pin 24 planted at one end of the connector 42 which is supported at
the other end by a pin 43 planted on one arm portion 15a of the
pressure applying arm 15. The link 41 has a free end portion 41a
which is connected by a connector 44 to the other arm portion 15b.
More specifically, the free end portion 41a is supported by a pin
45 planted at one end of the connector 44 which is supported at the
other end by a pin 46 planted on the other arm portion 15d.
In operation, clockwise pivoting of the pressure applying arm 15
about the pressure applying roller shaft 17 causes, through the
connector 42, the link 40 to pivot counter clockwise about the
shaft 25, so that the front end of the removal member 9 is brought
into pressing engagement with the periphery of the applicator
roller 4. Clockwise pivoting of the arm 15 about the shaft 17
simultaneously causes, through the connector 44, the link 41 to
pivot clockwise about the shaft 29, so that the front end of the
control member 5 is brought into pressing engagement with the
periphery of the supply roller 1.
From the foregoing description, it will be understood that the
rollers 6, 4 and 1 are released from pressing engagement with one
another and the members 5 and 9 are brought out of pressing
engagements with the peripheries of the rollers 1 and 4
respectively when the developing device is rendered inoperative, so
that deformation of the rollers can be precluded.
* * * * *