U.S. patent number 3,883,242 [Application Number 05/381,399] was granted by the patent office on 1975-05-13 for electronic photographic copying machine.
This patent grant is currently assigned to Canon Kabushiki Kaisha. Invention is credited to Masao Ariga, Motoharu Fujii, Kazuo Kawakubo, Susumu Sugiura, Isao Takahashi.
United States Patent |
3,883,242 |
Takahashi , et al. |
May 13, 1975 |
Electronic photographic copying machine
Abstract
An electrophotographic copying machine including a repetitively
usable photosensitive member removably mounted in the machine and
having a plurality of image processing elements including an image
transfer device disposed around the photosensitive member. The
photosensitive member is mounted within a first body portion of the
machine, while the transfer device is mounted in a removable second
body portion of the machine, whereby the photosensitive member is
accessible for removal when the two body portions are
separated.
Inventors: |
Takahashi; Isao (Yokohama,
JA), Fujii; Motoharu (Tokyo, JA), Kawakubo;
Kazuo (Tokyo, JA), Ariga; Masao (Tokyo,
JA), Sugiura; Susumu (Yamato, JA) |
Assignee: |
Canon Kabushiki Kaisha (Tokyo,
JA)
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Family
ID: |
27315487 |
Appl.
No.: |
05/381,399 |
Filed: |
July 23, 1973 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
Issue Date |
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211276 |
Dec 23, 1971 |
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Foreign Application Priority Data
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Dec 29, 1970 [JA] |
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45-12721 |
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Current U.S.
Class: |
399/125 |
Current CPC
Class: |
G03G
15/0867 (20130101); G03G 21/1623 (20130101); G03G
15/30 (20130101); G03G 21/1814 (20130101); G03G
2221/1657 (20130101); G03G 2221/1675 (20130101); G03G
2221/163 (20130101); G03G 2221/1654 (20130101); G03G
2215/0673 (20130101); G03G 2221/1687 (20130101); G03G
2215/0685 (20130101); G03G 2215/0678 (20130101) |
Current International
Class: |
G03G
21/18 (20060101); G03G 15/30 (20060101); G03G
15/00 (20060101); G03g 015/00 () |
Field of
Search: |
;355/3,16,11,14 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Horan; John M.
Attorney, Agent or Firm: Fitzpatrick, Cella, Harper &
Scinto
Parent Case Text
This is a division, of application Ser. No. 211,276, filed Dec. 23,
1971.
Claims
We claim:
1. An electrophotographic copying machine comprising a repetitively
usable electrophotographic photosensitive member; a group of
elements including an electrostatic latent image forming means,
developing means, transferring means and cleaning means, said
elements being disposed sequentially around said photosensitive
member, and said developing means and cleaning means being
contactable with said photosensitive member; transfer material
feeding means; fixing means; a lower main body portion for
supporting said photosensitive member, electrostatic latent image
forming means, developing means and cleaning means; and an upper
main body portion for supporting said transferring means and said
fixing means wherein, upon separation of said lower and upper main
body portions, said photosensitive member and a path for the
transfer material are accessible.
Description
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to generally an electronic
photographic copying machine, and more particularly to an
electronic photographic copying machine of the type capable of
automatically, rapidly and economically reproducing the
transparent, semi-transparent or opaque originals in the form of
sheet, especially the bank bills or the like.
2. Description of the Prior Art
In the reproduction of bank bills or the like, the original is, in
general, copied on a silver salt film, which is used as the
original to copy on paper by various photocopying processes such as
electrostatic processes. Therefore two steps are required to obtain
one copy, and the photocopying machines are complex in arrangement
and operation, large in size, and expensive and require a
relatively long time to make a copy. Of the various electrostatic
processes, xerography is in generally widely used. The
photoconductive layer used in xerography is exposed so that it
tends to be mechanically damaged. Furthermore, there is a problem
of its durability so that its photocopying ability is lost in a
relatively shorter time when a large number of copies are made.
Therefore, the photoconductive layer must be replaced from time to
time, thus resulting in high cost.
SUMMARY OF THE INVENTION
The present invention contemplates to eliminate the defects
encountered in the prior art photocopying processes and machines,
and to reproduce the bank bills or the like automatically, rapidly
and economically.
A primary object of the present invention is therefore to provide
an improved electronic photographic copying machine.
Another object of the present invention is to provide an electronic
photographic copying machine adapted for use in offices.
A further object of the present invention is to provide an
electronic photographic copying machine capable of transferring
image on ordinary paper or the like at high speed.
A still further object of the present invention is to provide an
electronic photographic copying machine in which an original is
exposed through slits twice or more in one receprocation thereof,
and is projected upon a photosensitive member, whereby copying
speed can be much enhanced.
A still further object of the present invention is to provide an
improved electronic photographic copying machine capable of
automatically placing an original in right position on an original
holder or the like.
A still further object of the present invention is to provide an
improved electronic photographic copying machine having an original
holder or the like upon which two originals of different sizes can
be placed so that they can be reproduced simultaneously.
A still further object of the present invention is to provide an
improved electronic photographic copying machine in which the inlet
of a developing agent container can be directed upwardly and
downwardly while the container is attached to a developing device,
whereby the supply of new developing agent and removal of used
developing agent can be much facilitated.
Another object of the present invention is to provide an improved
electronic photographic copying machine in which a predetermined
amount of developing agent can be supplied into the developing
chamber of the developing device in response to the rotation of
developing brush rollers.
Another object of the present invention is to provide an electronic
photographic copying machine in which a part of its casing is
detachably attached so that the removal of jammed copying paper and
the inspection and repair of various devices disposed within the
casing can be much facilitated.
Another object of the present invention is to provide an improved
electronic photographic copying machine in which the attachment of
a photosensitive member to a drum and the removal thereof from the
drum can be made in a simple manner.
Briefly stated, the present invention is based upon an electronic
photographic process disclosed in U.S. Pat. No. 3,438,706
comprising the steps of uniformly charging the surface of a
photosensitive member comprising a support, a photoconductive
layer, and an insulating layer; projecting the image of an original
upon the surface of said photosensitive member simultaneously when
said photosensitive member is subjected to the second charging with
the polarity opposite to that of said first charging step or a-c
corona discharge; and, if required, emitting the radiation to
illiminate said photosensitive member, thereby forming an
electrostatic latent image of high contrast. The originals such as
bank bills or the like can be directly copied on ordinary paper or
the like, and an electronic photographic copying machine in
accordance with present invention is simple in construction and
operation and small in size, and is capable of reproducing copies
at high speed and at less cost.
The above and other objects, features and advantages of the present
invention will become more apparent from the following description
of the preferred embodiments thereof taken in conjunction with the
accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWING
FIG. 1 is a perspective view of an electronic photographic copying
machine in accordance with the present invention;
FIG. 2 is a longitudinal sectional view of the electronic
photographic copying machine shown in FIG. 1;
FIG. 3 is a longitudinal sectional view of an original
transporation device in the machine;
FIG. 4 is a top view of the original transporation device;
FIG. 5 is a diagram of a control circuit for the original
transporation device;
FIG. 6 is a perspective view of a photosensitive drum;
FIG. 7 is a longitudinal sectional view of the photosensitive
drum;
FIG. 8 is a perspective view used to explain the relation between
the photosensitive drum and a transfer roller;
FIG. 9 is a transverse sectional view of the device shown in FIG.
8;
FIG. 10 is a perspective view of a developing device;
FIG. 11 is a transverse sectional view of the developing
device;
FIG. 12 is a top view of the developing device with a cover
removed;
FIG. 13 is a sectional view of a toner supply section;
FIGS. 14 and 15 are left and right side views of a cleaning device,
respectively;
FIG. 16 is a front view of the cleaning device;
FIG. 17 is a side view of the copying machine used for explanation
of driving mechanism of the machine;
FIGS. 18 and 19 are front views of control cam mounting disks;
FIG. 20 is a flow chart used to explain the sequence of operations
of switches;
FIG. 21 and FIGS. 23 (a) and (b) are views used to explain the mode
of opening and closing an upper main body of the copying machine
with respect to the lower main body;
FIG. 22 is a side view used for explanation of driveing means;
and
FIG. 24 is an electric circuit diagram of the copying machine.
DESCRIPTION OF THE PREFERRED EMBODIMENT
Referring to FIG. 1, an electronic photocopying machine in
accordance with the present invention generally designated by 1
comprises a main body section 2 and a carriage section 3. At the
center of the front wall of the machine 1 is formed an original
inlet-outlet 4 through which is inserted an original, and a copy C
is discharged from a copy outlet 5 onto a copy stand 6.
Next referring to FIG. 2 illustrating the longitudinal sectional
view of the photocopying machine, an electronic photographic drum 7
in accordance with the present invention comprises a photosensitive
member 8 which in turn comprises a surface insulating layer, a
photoconductive layer, and an insulating supporting layer laminated
in the order named. Around the photosensitive drum 7 which rotates
in the direction indicated by the arrow are disposed a first or
primary charger 9, a simultaneous image-projection-and-discharge
device 10, a whole-surface-exposing device, a developing device 12,
a third charger 13, an image transfer device 14, and a cleaning
device 15 in the order named.
The first charger 9 applies the DC corona discharge to the surface
of the sensitive member 8 fixed around the drum 7, thereby
imparting thereto the positive or negative charge. Next the
simultaneous image-projection-and-discharging device 10 applies to
the photosensitive drum 7 the d-c corona discharge of the polarity
opposite to that of the d-c discharge applied by the first charger
9 or the a-c corona discharge, simultaneously when the light image
of the original is projected upon the photosensitive drum 7. As a
result, an electrostatic latent image is formed upon the
photosensitive drum 7.
The whole-surface-exposing device 11 uniformly exposes or
illuminates the whole surface of the photosensitive drum at which
the electrostatic latent image is formed to impart the external
field thereto, thereby improving the contrast of the electrostatic
latent image. The whole-surface-illumination device is not
necessarily required. The latent image thus formed is developed by
the developing device 12 which applies the toner of the polarity
opposite or same to that of the latent image. It is preferable to
employ the fur-brush, magnet-brush, cascade or wet developing
method as the needs demand.
The third charger 13 is not necessarily required, but is used to
impart the charge of an appropriate polarity to the copying medium
P (which is generally paper) in order to enhance the electrostatic
transfer of the powder image formed upon the photosensitive drum 7
to the copying paper P by the image transfer device 14. After the
image has been transferred, the toner still remaining upon the
photosensitive drum 7 is wiped off by a cleaning roller 16 in the
cleaning device 15.
In addition to the peripheral devices 9-16 disposed around the
photosensitive drum 7, the photocopying machine in accordance with
the present invention further includes an original transportation
or feed device, an optical system for projecting the image of the
original upon the photosensitive drum, a copy paper feeding device,
a copying paper separating device, a fixing device and so on, and
the present invention is characterized by the arrangements thereof
as will become more apparent from the following description of the
various devices.
ORIGINAL TRANSPORTATION DEVICE
As shown in FIGS. 3 and 4, the original transportation device
generally comprises an original holder or stand 17 upon which is
placed the original O inserted through the original inlet-outlet 4,
a pair of conveyor belts 18 wrapped around rollers 19 and 20 and
disposed below the both lengthwise sides of the original stand 17 a
wire 21 for transporting the original stand 17, wrapped around a
pulley 22 and a capstan 23, photoconductive cells 24, 25 and 26,
and light sources 27, 28 and 29. The original stand 17 is adapted
to receive and hold the originals of two different sizes at
17.sub.1 and 17.sub.2, respectively, and is transported along a
pair of guide rails 30.
The original O (which is, for example, a bank bill) is inserted
into the inlet 4 with the image to be copied faced upward. Then the
light from the light source 27 to the photoconductive cells 24 is
interrupted by the original O so that a switching circuit S1 in a
control circuit shown in FIG. 5 is actuated to energize an output
relay K3 to close its contacts, thereby energizing relays A and B.
As a result, a motor M6 for transporting the original is energized
to rotate the conveyor belt 18 so that the original O is
automatically moved onto the section 17.sub.1 of the original
holder 17. The original O interrupts light from the light sources
28 and 29 to the photoconductive cells 25 and 26 respectively so
that both switching circuits S2 and S3 are simultaneously actuated
to energize output relays K4 and K5 to close their contacts. As a
result, the relays A, B and C are energized, and a drum clutch CL5
is engaged so that the original stand 17 is transported in the
direction indicated by the arrow through the capstan 23, the pulley
22 and the wire 21. When light is received by the cells 24, 25 and
26 from the light sources 27, 28 and 29 as the original stand 17 is
moved away therefrom, the switching circuits S1, S2 and S3 are
de-energized so that the output relays K3, K4 and K5 are
de-energized. Therefore, their contacts are opened, and the relays
A, B and C are de-energized, whereby the motor M6 is stopped.
When the original O is fed at an angle relative to the longitudinal
axis of the original stand 17, either of the photoconductive cells
25 and 26 receives light from the light source 25 and 26. In this
case, the motor M6 is driven to correct the position of the
original O on the original stand 17, but the drum clutch CL5 is not
engaged. Only after the original O is placed correctly upon the
original stand 17 so that both the photoconductive cells 25 and 26
are interrupted from receiving the light from the light sources 28
and 29, the drum clutch CL5 is engaged to transport the original
stand 17.
When the original stand 17 is reversed in direction from the going
to the return stroke, microswitches MS7-MS10 (which are mounted
upon the photosensitive drum 7) are closed to reverse the capstan
23. As a result, the original holder 17 is returned to the initial
position, shown in FIG. 3, at which the light from the light
sources 28 and 29 to the photoconductive cells 25 and 26 are
interrupted so that the output relays K3 and K4 are energized to
energize the relays A and C. Since the relay B is not energized,
the auxiliary coil L.sub.2 of the motor M6 is excited in the
direction opposite to that of the main winding L.sub.1 so that the
motor M6 is reversed to reverse the conveyor belt 18. As a result,
the original O is discharged through the outlet 5, and the operator
may pull the original O from the outlet. Then, the light from the
light source 27 is intercepted by the photoconductive cell 24 so
that the relay A is de-energized. As a consequence, the motor M6 is
stopped.
The photoconductive cell 24 and the conveyor belt 18 may be so
arranged that the relay A remains energized so long as the original
O is pulled away from the stand 17 by the operator. This
arrangement is advantageous in that even when the original O is
inserted again after one cycle of photocopying process has been
completed, the motor M6 is not driven in the direction in which the
original O is moved upon the stand 17.
When a plurality of copies are desired from the same original O, a
copy-number-setting dial 31 (See FIG. 1) is set to 2 or M. The
original stand 17 is reciprocated as many times as the number of
copies set. That is, when the original stand 17 is returned to its
initial position and the photoconductive cells 25 and 26 are
interrupted from receiving light from the light sources 28 and 29,
the conveyor belt 18 is driven to move the original O toward the
outlet. When the light from the light sources 28 and 29 is received
again by the photoconductive cells 25 and 26, the original O is
returned to the original stand 17.
When it is desired to copy a number of different bills for the same
client, a form O.sub.2 in which are filled the name and account
number of the client is plated at 17.sub.2 on the original stand
17, and the bills O.sub.1 are sequentially fed into the
photocopying machine. In this manner, the originals or bills
O.sub.1 can be copied together with the form O.sub.1 on the same
copying papers.
A plurality of rollers may be used in place of the conveyor belts
18, and microswitches may be employed instead of the
photoconductive cells 24, 25 and 26.
OPTICAL SYSTEM FOR EXPOSURE
The exposure system is housed in a dust-proof chamber 33
partitioned by a partition wall 32 as shown in FIG. 2, so that the
optical system is completely separated from the devices disposed
above the dust-proof chamber 33. Therefore, the optical system and
especially its reflectors 36-38 and lenses 34 and 35 are completely
prevented from being contaminated by the developing agent or the
like. Furthermore, the independent optical system chamber
facilitates the assembly, adjustment of the optical elements, and
periodic cleaning and maintenance services of the optical system.
According to the present invention, two slit-exposures are made in
one going stroke of the original stand 17, so that there are two
slit-exposure devices 39 and 40.
The image light emitted from the exposure device 39 is directed
along the optical path P.sub.1 comprising the lens 34 and two
reflecting mirrors 36 and 38, whereas the light emitted from the
exposure device 40 is directed along the optical path P.sub.2
comprising the lens 35 and two reflecting mirrors 37 and 38, to the
photosensitive layer 8 on the drum 7 through the simultaneous
image-projection-and-charging device 10. When the image is
projected by the first slit-exposure device 39, the lens 35 in the
second optical path P.sub.2 is closed by a shutter 41 in order to
prevent the image light in the second path P.sub.2 from being
projected upon the drum 7. Simiarly, the lens 34 is closed by a
shutter 41' when the image is projected along the second optical
path P.sub.2. The shutters 41 and 41' are actuated by an
electromagnetic clutch which is energized by a microswitch MS5
which in turn is closed and opened as the drum 7 rotates.
DEVICES ASSOCIATED WITH FORMATION OF ELECTROSTATIC LATENT IMAGE
As shown in FIGS. 6 and 7, the photosensitive drum 7 is cut away at
7.sub.1 in parallel with the axis of the drum. Both ends of the
photosensitive member 8 in the form of a sheet are retained by
retaining plates 8.sub.1 and 8.sub.2 as best shown in FIG. 6. After
the photosensitive member 8 is wrapped around the cylindrical
surface of the drum 7, engaging holes 8.sub.3 formed in the
retaining plates 8.sub.1 and 8.sub.2 at one end of the
photosensitive member 8 are fitted over retaining pins 42 extending
from the cutaway portion 7.sub.1 of the drum 7, whereas a spring 43
whose both ends are securely fixed to the retaining plates 8.sub.1
and 8.sub.2 at the other end of the photosensitive member 8 is
hooked to a retaining pin 44 extending from the cutaway portion
7.sub.1. Thus, the photosensitive member 8 may be securely
maintained around the drum 7.
On both sides of the drum 7 are coaxially disposed disks 45 and 46
which rotate independently of each other, and a pair of guide
rollers 48 attached to both sides of the cleaning roller 16 are
made into contact with the disks 45 and 46 respectively. Similarly
the side portions of an image transfer roller 47 which is slightly
longer than the axial length of the drum 7, ride over the disks 45
and 46 as shown in FIGS. 8 and 9. The diameter of the disks 45 and
46 is equal to that of the drum 7 including the photosensitive
member 8 wrapped therearound so that the transfer roller 47 may be
firmly pressed against the photosensitive member 8.
A copying-paper separating belt 49 is wrapped around the transfer
roller 47 through 180.degree., and is guided by pulleys 50-54 to be
moved in unison with the transfer roller 47. It is seen that the
separating belt 49 is moved away from the path of the copying paper
by the pulleys 50-54.
As the photosensitive member 8 on the drum 7 is moved away from the
transfer roller 47, the spacing t is formed therebetween as shown
in FIG. 9, but the disks 45 and 46 keep contact with the transfer
roller 47 as described hereinbefore so that it is rotated, and the
separating belt 49 wrapped therearound is transported. In other
words, even when the drum 7 is stopped, the transfer roller 47 is
rotated, and the separating belt 49 is transported so that copying
paper P can be positively fed into the fixing device 55, and that
the local heating of the transfer roller and separating belt from
the fixing device 55 can be prevented.
The drum 7 starts rotation when both the photoconductive cells 25
and 26 are interrupted from receiving light from their light
sources 28 and 29 by the original O. The photosensitive drum is
first charged by the first charger 9, and then by the second
charger 10 simultaneously when the image of the original O is
projected upon the photosensitive drum 7 and is illuminated
uniformly by the whole-surface-illumination device 11 to form an
electostatic latent image having high contrast.
DEVELOPING DEVICE
As shown in FIGS. 10-13, the developing device comprises a pair of
developing rollers 56 and 57, a pair of screws 59 and 60 for mixing
and feeding developing agent 58, a toner feed roller 61 for feeding
a predetermined amount of toner, a toner transfer brush 62, and a
toner supply chamber 63. Toner fed from a hopper 64 drops into the
recesses of the knurled toner feed roller 61, and a doctor blade 65
in contact with the feed roller 61 prevents excess toner from
dropping onto the toner transfer brush 62. That is, a predetermined
amount of toner is always fed to the screw 60 in the supply chamber
63 through the toner transfer brush 62. Toner is mixed with carrier
iron powder to provide the developing agent 58 which is fed into a
developing chamber 66 by the mixing and conveyor screw 60. In the
developing chamber 66, the developing agent is circulated in a
predetermined direction through holes 67.sub.1 and 67.sub.2 through
a partition wall 67 by the pair of screws 59 and 60. The screw
thread 59' at the left end of the screw 59 is reversed in direction
so that the developing agent can be positively forced into the hole
67.sub.2 toward the screw 60 at the intersection between the
reversed screw thread 59' and the forward screw thread 59".
Developing agent being fed by the screw 59 is magnetically
attracted by the pair of developing rollers 56 and 57 which are
rotating at 100-300 rpm. The developing agent is transferred from
the pair of developing rollers 56 and 57 to the photsensitive
member 8, whereby the electrostatic latent image formed thereupon
in the manner described hereinbefore may be developed into a
visible powder image. Control blades 68 are provided in order to
control the amount and uniform attachment of developing agent on
the developing rollers 56 and 57.
The screw 60 is extended into a cylinder 70 disposed in casing 69
of the developing device, and another cylinder 71 is rotatably
fitted into the cylinder 70. The toner container 64 is detachably
attached to the cylinder 71 as shown in the chain lines in FIG. 12
in such a manner that when the cylinder 71 is rotated to the
position indicated by the solid lines, the opening 71.sub.1 of the
cylinder 71 coincides with the developing agent supply inlet or
opening 70.sub.1 of the cylinder 70.
Therefore, a predetermined amount of toner is supplied to the feed
roller 61. In order to adjust the amount of toner to be supplied, a
cam 72 carried by the shaft 59.sub.1 of the screw 59 is inclined so
that a lever 73 in contact with the cam 72 changes its angle or
inclination. As a result, the angle of rotation of a ratchet wheel
74 can be varied so that the number of rotations of the feed roller
61 relative to one rotation of the shaft 59.sub.1 can be changed.
Thus, the amount of toner to be supplied can be adjusted.
When the developing agent 58 is fatigued after a long use so that
it must be exchanged with new developing agent, the cylinder 71 is
rotated to displace the toner container 64 to the position
indicated by the chain lines, whereby the opening 71.sub.1 of the
cylinder 71 coincides with the developing agent discharge outlet or
opening 70.sub.2 of the cylinder 70, and then the screw driving
motor is reversed to return the developing agent in the developing
chamber 66 into the toner supply chamber 63. Therefore, the
developing agent is returned into the toner container 64. Thus,
unlike the prior art developing device, it is not required to
remove the developing device from the main body of the photocopying
machine for exchange of developing agent.
In the instant embodiment, the magnet brush developing method is
illustrated, but it is understood that the fur brush developing
method may be also employed.
As shown in FIG. 10, the casing 69 of the developing device is
mounted upon a supporting plate 75, and is moved along guide rails
76 to the operative position at which the developing device is
securely held to the main body of the photocopying machine with a
locking knob 77.
COPYING PAPER FEED DEVICE, IMAGE TRANSFER DEVICE, DEVICE FOR
SEPARATING COPYING PAPER, AND FIXING DEVICE
Copying papers P on a copying paper stand 78 (See FIG. 2) are fed
one by one by a feed roller 79 whose rotation is controlled in
response to the signal from a cam mechanism in the control unit 80
(See FIG. 7) which in turn is controlled by a microswitch MS11
attached to the feed roller 79. Copying paper P is transported by a
pair of feed rollers 81 to a second pair of feed rollers 82. The
first pair of feed rollers 81 are initially stopped so that copying
paper P is bowed, and the leading edge of copying paper is aligned
with the axes of the first pair of feed rollers 81. In the instant
embodiment, sheet copying papers are used, but it is understood
that a rolled copying paper is also used when cutting means for
cutting a rolled copying paper into a predetermined size.
The first pair of feed rollers 81 start to rotate when the control
switch MS 12 is actuated by the cam mechanism in the control unit
80 as shown in FIGS. 7, 14, and 15, and copying paper P is
transported by the second pair of feed rollers 82 which are
normally rotated, toward the image transfer device. In the image
transfer device, the copying paper is registered with the zone of
the photosensitive drum 7 upon which is formed the toner image, and
is pressed by the transfer roller 47 against the photosensitive
drum 7. As a result, the toner image is transferred upon the
copying paper.
As shown in FIGS. 6 and 8, the copying paper P to which has been
transferred the toner image from the drum 7 is deparated from the
photosensitive drum 7 because the side edge of the copying paper P
is sandwiched between the separating belt 49 and the transfer
roller 47. Thereafter, copying paper is transported toward the
fixing device by a separating pawl 83 in light contact with the
transfer roller 47.
The fixing device comprises a conveyor belt 84 made of wire
netting, infrared lamps 85, and a reflector 86. the temperature in
the fixing device is always maintained at a predetermined level so
that the toner may be fused and fixed to the copying paper to
provide a permanent record.
A fan or the like may be provided to suction the air in the loop of
the conveyor belt 84 so that the copying paper may be firmly
pressed against the belt 84 and the temperature rise of the belt
made of wire netting can be positively prevented. The fixed copying
paper is discharged by pairs of discharge rollers 87 and 88 onto a
receiving tray 6.
CLEANING DEVICE
As shown in FIGS. 14, 15 and 16, the cleaning roller made of rubber
around the peripheral surface of which is applied fabric, removes
toner still remaining on the photosensitive drum 7 after the toner
image has been transferred to the copying paper P. The toner
attached to the cleaning roller 16 in turn is removed by a brush
roller 89, and the toner attached to the brush roller 89 is removed
by a beating member 90 and is dropped into a bag or container
91.
A supporting member 92 of the cleaning device 15 is pivoted with a
pin 93 to the main body, and an ear 94 formed at the upper portion
of the cleaning device 15 is loosely engaged with a pin 97
extending from a casing 96. The cleaning roller 16 is pressed
against the photosensitive drum 7 under an appropriate pressure of
a spring 98. The rotation of a driving motor (not shown) is
transmitted through a gear 99, and a chain 100 to the cleaning
roller 16, whereas the rotation is transmitted to the brush roller
89 through a gear 101 and a chain 102.
OTHER MECHANISMS
As shown in FIG. 7, a rotary shaft 103 of the photosensitive drum 7
is supported through bearings 106 and 107 by side walls 104 and
105, and is driven by a gear shaft 108 which carries an
electromagnetic clutch CL6 at one end thereof and is driven by a
main motor M1 through gears 109, 110, and 111 and a chain 112
wrapped therearound as shown in FIG. 17. The shaft 108 also rotates
a cam disk 113 in the control unit 80. When light is interrupted by
the original O to be received by the photoconductive cells 25 and
26 (See FIGS. 3 and 4), a switch MS13 is closed to actuate the
electromagnetic clutch CL6, whereby the photosensitive drum 7 is
started to rotate. At the same time, the cam disks 113 and 114
starts to rotate, and the switches MS1, MS2, MS11, MS12, MS13, MS5,
MS3, MS9, and MS7 mounted upon the disks 113 and 114 (See FIGS. 18
and 19) are actuated in the sequence shown in FIG. 20, whereby the
photocopying machine can be controlled.
According to the present invention, the upper main body 1 which
carries the transfer roller 47 is detachably mounted on the lower
main body 11 which carries the photosensitive drum 7 so that the
removal of jammed copying paper can be facilitated, and other
servicings can be much enhanced. The gears 115 and 116 carried by
the lower main body 11 are in mesh with the gears 117 and 118
carried by the upper main body 1 as shown in FIGS. 17 and 22 so
that the power for driving the feed rollers and discharge rollers
81, 82, 87, and 88 and the rollers 119 and 120 for driving the
conveyor belt 84 in the fixing device all of which are disposed in
the upper main body 1 can be transmitted from the motor mounted in
the lower main body 11. It is seen that the power transmission
systems in the upper and lower main bodies 1 and 11 can be also
easily coupled and disconnected.
As shown in FIG. 21, hinge arms 121 securely fixed to the side
walls of the upper main body 1 are pivoted to the lower main body
11, and a ratchet pawl wheel 123 is fixed to each of supporting
arms 122 fixed to the side walls of the lower main body 11. Pawls
124 for engagement with the ratchet pawl wheel 123 are securely
fixed to the upper main body 1.
When the upper main body 1 is opened as indicated by the two-dot
chain lines as shown in FIG. 21, the pawls 124 causes the ratchet
pawl wheel 123 to rotate. When the upper main body 11 is slightly
lowered in the position shown in FIG. 23(a), a notch 124.sub.1 of
the pawl 124 engages with a ratchet pawl 123.sub.1 so that the
upper main body 1 can be maintained in opened position. When the
upper main body 1 is raised to bring the ratchet pawl wheel 123 to
the position shown in FIG. 23(b) by the pawl 124, the notch
124.sub.1 is released from the ratchet pawl 123.sub.1 so that the
upper main body 1 can be losed.
The carriage 3 shown in FIGS. 1, 2, 17 and 22 incorporates therein
an electric unit and a toner collecting device for collecting toner
scattered from the developing device.
ELECTRIC CIRCUITS
Upon depression of a power switch P. B., a pilot lamp PL1 is turned
on, and simultaneously the main motor M1 and a fan motor M2 for
collecting scattered toner are started and normally driven, and
when the original O is inserted to interrupt light from the light
source to the photoconductive cell 24, the output relay K3 is
energized, and the control circuit C5 for controlling the
transportation of original is actuated so as to transport the
original O. When the original O is correctly placed on the original
stand 17, and interrupts light to the photoconductive cells 25 and
26, the output relays K3-K6 are energized so as to engage the
clutch CL5, whereby the photosensitive drum 7 starts to rotate.
Since the microswitch MS13 is closed, the drum continues its
rotation, and when the control microswitch MS3 attached to the drum
is closed, a high voltage transformer HVT and a relay K1 are
energized to turn on an illumination lamp FL. Since the microswitch
MS11 attached to the photosensitive drum is closed, copying paper
is fed toward the photosensitive drum while closing the switch
MS12, and the toner image formed upon the photosensitive drum is
transferred upon copying paper. A motor M5 for driving the cleaning
device is driven when the microswitch MS1 is closed. The
reciprocation of the original stand 17 is controlled by clutches
CL2 and CL3 which in turn are controlled by microswitches MS7 and
MS9 attached to the photosensitive drum and switches MS8 and MS10
attached to the timing drum.
In the photocopying machine in accordance with the present
invention, two copies are obtained from one original. Therefore, a
timing switch MS5 is attached to the photosensitive drum in order
to control a shutter control clutch CL1 to alternately close the
shutters 41 and 41'.
In FIG. 24, H designates a heater in the fixing device; F2, and a
fuse for the heater H. The relay K2 constitutes an interlocking
circuit for disconnecting the contacts K2 when lamps PL3-PL5 for
CdS are turned off so as to de-energize the original transportation
control circuit C5 to prevent the original from being transported
for exposure.
An alarm circuit C3 is provided for flickering a pilot lamp PL7 or
PL8 when copying paper is jammed. C4 is a timer circuit for
exposure; K11, contacts which are closed when the photosensitive
drum is stopped, so as to control the circuit C4; and C6, an
electronic counter circuit for counting the number of copies
reproduced and de-energizing the control circuit C5, when the
desired number of copies are reproduced, so as to stop the feeding
of copying papers. M3 is an exhaust fan motor; and C1, a control
circuit which varies the rotational speed of the exhaust fan motor
M3 when the heater H reaches a predetermined temperature in order
to exhaust the heated air out of the fixing device, whereby the
overheat can be prevented. F is a fuse for protecting an AC power
source circuit; F3, a fuse for protecting a DC power source; and
PL2, a lamp for preliminary exposure.
As described above, according to the present invention, around the
photosensitive drum are disposed the first charger, the second
charger or simultaneous image-projection-and-charging device; the
whole-surface-illumination device; the developing device; the third
charger, if required; the image transfer device, and the cleaning
device in the order named. On one side of the photosensitive drum
is disposed two slit-exposure optical systems, and above the
optical systems are disposed the original transportation device and
the copying paper feed device. Therefore, two images of the same
original can be reproduced on the same copying paper by one
reciprocation of the original stand and hence the original. The
photocopying machine in accordance with the present invention can
be made compact in size. Since the fixing device is disposed in the
uppermost portion in the casing, other devices, and especially the
optical systems can be prevented from being heated. Therefore the
heat problems can be easily solved, and the lenses can be
sufficiently protected. Since the optical systems are housed within
the independent dust-proof chamber, they are prevented from being
contaminated with toner and the like.
The original is automatically fed upon the original stand under the
control of detecting means, and is placed correctly upon the stand
when the latter is reciprocated. There is no fear that jamming of
original occurs in the original transportation path. The original
stand is provided with two original receiving sections so that two
originals of different sizes can be reproduced at the same
time.
The photosensitive member in the form of sheet can be securely
placed around the drum because one end of the photosensitive member
is retained in position on the cutaway portion of the drum with the
pins, whereas the other end thereof is retained in position with
the spring. Therefore, even when the photosensitive member is
expanded or contracted by heat, it can be made into close contact
with the drum. Furthermore, the photosensitive member can be easily
replaced. Since the drum is cutaway in the manner described
hereinbefore, it may be stopped while the transfer roller rotates,
and the copying paper feed device is actuated.
The toner supply chamber is defined by the cylinder fitted into the
developing device, and the toner container is attached to the
cylinder which is rotatably fitted into the first cylinder. The
screw is extended into the toner supply chamber so that toner
supplied from the container can be immediately fed into the
developing chamber. When the screws are reversed in rotation, the
developing agent can be returned from the developing chamber to the
toner supply chamber and then into the toner container. Therefore,
the need of removing the developing device for exchange of
developing agent can be eliminated.
Copying paper is sandwiched between the transfer roller and the
separating belt, and is moved away from the drum along the transfer
roller so that the copying paper which is attached to the drum
under the electrostatic force can be easily and smoothly separated
from the drum.
Toner remaining on the photosensitive drum can be removed by the
cleaning roller made of rubber or synthetic resin, and toner
attached to the cleaning roller can be removed by the brush roller
in contact with the cleaning roller. Thus, the photosensitive drum
can be completely cleaned by the simple cleaning device. If
necessary, the cleaning roller may be knurled.
The heated air in the loop of wire netting conveyor belt in the
fixing device can be exhausted so that the copying paper can be
securely pressed against the belt and prevented from making contact
with the heater. Furthermore the temperature rise of the conveyor
belt can be prevented.
The upper main body in which are mounted the transfer roller, the
separating belt, and the cleaning device, is hinged to the lower
main body in which is mounted the drum in such a manner that the
upper main body may be opened along the copying paper feed device.
Therefore the removal of jammed copying paper can be much
enhanced.
To remove the photosensitive member attached around the drum, the
cleaning device is moved away from the drum, and thereafter the
upper main body is opened in the manner described hereinbefore. A
dust-proof cover 125 fixed to the drum to cover the cutaway portion
thereof is removed, and the spring and engaging holes at the ends
of the photosensitive member are disengaged from the retaining pins
on the cutaway portion of the drum. Thus, the photosensitive member
can be removed from the drum. In reversing the steps described
above, the photosensitive member can be easily attached around the
drum.
Since the cleaning device can be moved away from the drum, the
inspection, adjustment, repair and maintenance of the chargers, the
whole-surface-illumination devices and so on disposed around the
drum can be easily carried out.
It is understood that the present invention is not limited to the
embodiment described hereinbefore with reference to the
accompanying drawings, and that various variations and
modifications can be effected without departing from the scope of
the present invention. For example, any of the conventional
electrophotographic processes can be employed in the photocopying
machine in accordance with the present invention.
In summary, the advantages of the photocopying machine in
accordance with the present invention will be described.
Since the main body of the photocopying machine comprises the upper
and lower main bodies which can be separated from each other, the
removal of jammed copying paper, the inspection, adjustment, repair
and the like of the fixing device, the image transfer device and
the cleaning device can be much facilitated without disassemblying
the machine.
Even when the original is inserted into the inlet in any position,
it is automatically placed in correct position. Therefore, the
operator can reproduce a large number of copies without fatigue and
without excercising much care in insertion of original.
Even when original makes one rotation, it is exposed twice.
Therefore, the copying speed can be much enhanced. Since the
original is not subjected to bending, even the original which has a
tendency of being folded may be completely copied.
The toner supply container is attached to and detached from the
developing device, with its inlet remained upstanding. Therefore,
the supply of new toner can be much facilitated.
Since the developing agent can be supplied from the developing
agent supply container to the inside of the developing device, the
images of the reproduced copies can be much improved in
quality.
The photosensitive member can be attached to the drum in a simple
manner, and for replacement thereof, it is not required to remove
the whole drum from the machine.
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