JP2886558B2 - Multiple image forming device - Google Patents

Description

The present invention relates to a multiple image forming apparatus, for example, a multi-color or full-color copying machine, a color printer, a color facsimile, and the like.

(Prior art)

In a conventional multiplex image forming apparatus such as a copying machine, a transfer drum is used, a transfer material is wrapped around the transfer drum, rotated synchronously with the drum-shaped latent image carrier, and a plurality of images sequentially formed on the latent image carrier are transferred. It has been put to practical use that the transfer material is separated from the transfer drum, fixed, and discharged after transfer.

In the conventional multiple image forming apparatus, the transfer material needs to be wrapped around the transfer drum in a single layer, so that the transfer drum becomes large and the apparatus becomes large. Further, the transfer drum is easily stained with the toner, which causes stain on the back surface of the transfer material. Therefore, a cleaning device for cleaning is required, and the device becomes complicated and expensive. Also, it was difficult to use a transfer material having a strong strain such as cardboard.

Conventionally, in a multi-color copying machine, a transfer material is conveyed to an intermediate sheet feeding section for multiplex copying after image formation, and a multiplex image is formed by a transfer material conveyance method similar to that of normal mono-color copying. However, it has been inevitable that the alignment of the image becomes uncertain, the transfer material transporting form becomes complicated, the apparatus becomes large, and the reliability is reduced.

Further, a multi-transfer device that uses a transfer belt to electrostatically adsorb a transfer material to the transfer belt and conveys the transfer belt has been studied. However, there is a problem in the stability of the electrostatic attraction, and when forming multiple images, multiple images are transferred. Since the transfer belt is contaminated with toner similarly to the transfer drum, there is a problem in alignment, and a cleaning device for the belt is required, which complicates the device, increases the cost, and lowers the reliability.

In order to solve these problems, the present applicant supports a transfer material by a transfer material carrier, and linearly reciprocates the transfer material in a tangential direction of the latent image carrier to form a plurality of latent image carriers on the transfer material. A multiple copying apparatus for superimposing and transferring images is disclosed in, for example, Japanese Patent Application Laid-Open No. Sho 62-203172.
, JP-A-63-161469 and JP-A-63-161470.

Although simplification and miniaturization of the apparatus have been achieved by such a multiplex copying apparatus, there are still problems in terms of transfer material transferability and transfer efficiency of the latent image carrier.

[Problems to be solved by the invention]

SUMMARY OF THE INVENTION It is an object of the present invention to solve the above-mentioned conventional problems and to provide a multiple image forming apparatus having good transportability and transfer efficiency.

[Means for solving the problem]

An object of the present invention is to provide a drum-shaped latent image carrier, a developing device for developing a latent image, and a transfer material transporter that can reciprocate linearly in a tangential direction of the latent image carrier at a transfer unit. In a multiplex image forming apparatus for transferring a plurality of toner images sequentially formed on the latent image carrier onto a transfer material which is supported by the transfer material carrier and conveyed reciprocally, the transfer material carrier is transferred A transfer material support portion of the transfer material transport member having a transfer material transfer portion and a transfer material support portion, and a transfer start position slightly upstream of the transfer position by the latent image carrier in the transfer material feed direction. After supporting the transfer material fed by at least one pair of paper feed rollers arranged in the printer, after the start of the transfer for transfer of the transfer material conveyance body, each paper feed is performed until at least the rear end of the transfer material passes. The roller pair is held in a paper release state, wherein the multiple image type is provided. It was solved by the device.

[Action]

According to the present invention, a pair of paper feed rollers provided with a paper feed path for feeding the transfer material so as to be gripped by the transfer material support portion at the transfer start position, the transfer material conveyance body starts moving to start the transfer, and the transfer material Until the trailing end passes through the pair of paper feed rollers, the paper feed is released, for example, the pair of paper feed rollers is kept separated from each other, and it is possible to prevent transfer resistance from being applied to the transfer material. The transfer material is reliably transported by the transfer material transport body, so that the transportability is improved and the adhesion to the latent image carrier is maintained.

〔Example〕

 The details of the present invention will be described based on an embodiment shown in the drawings.

In FIG. 1, a document 2 placed on a document table 1 is illuminated by an exposure lamp 4 of an exposure optical device 3, and reflected light from the document 2 is reflected by a first reflection mirror 5, a second reflection mirror 6, The light is sequentially reflected by the three reflection mirrors 7 and enters the lens system 8, and the light emitted from the lens system 8 is reflected by the fourth reflection mirror 9, the fifth reflection mirror 10, and the sixth reflection mirror 11,
Irradiation is performed on the photoconductor 12, for example, a photoconductor drum. In the case of color copying of a color original, a filter 13 is arranged in the optical path reflected by the sixth reflecting mirror 11 and irradiated on the photoreceptor 12. The filter 13 is, for example, a blue filter 13B, a green filter 13G, a red filter
13R, a neutral filter for black image 13BK has four types of filters, and one of the four types of filters is rotated to a predetermined angle so that one of the four types of filters is placed in the optical path so that each filter can be switched and arranged in the optical path. It is configured to be arranged vertically. Image light from the original is color-separated by a filter 13 and
Is irradiated with image light of each of the separated colors.

When the original is exposed and scanned by reciprocating the exposure lamp 4, the exposure lamp 4 and the first reflection mirror 5 are carried by the first scanner and scanned at a predetermined speed. The three-reflection mirror 7 is carried by the second scanner and scans at half the speed of the first scanner.

The photoreceptor 12 is charged by the charger 14, and the exposure optical device 3
To form an electrostatic latent image of one separated color image, and the developing device 15
Is developed with a developing material of a color corresponding to the type of the filter 13 to obtain a separated color visible image.

The developing device is, for example, a yellow developing device 15Y containing a yellow developer, a magenta developing device 15M containing a magenta developer, and an undeveloping device 15C containing a cyan developer.
It has a black developing device 15BK that contains black developer, for example, the four-color developing devices 15Y, 15M, 15C, and 15BK are arranged around a rotation axis in a circular shape to form a rotary (revolver type) developing device. I do.

When a separated color latent image is formed on the photoreceptor 12 by the blue filter 13B, the developing roller 1 of the yellow developing unit 15Y
5'Y moves to the developing position D with respect to the photoconductor 12, and is developed with a yellow developer, for example, a yellow toner. Similarly, the magenta developing device 15M is used for the color separated by the green filter 13G, the cyan developing device 15C is used for the color separated by the red filter 13R, and the black developing device 15BK is used for the color separated by the neutral filter 13BK. Done.

The photoreceptor 12 on which the visible image of the separated color image is formed by the development of the developing device 15 is discharged by the charge removing lamp 16 to reduce the electric attraction force between the toner and the photoreceptor,
Transferability in the subsequent transfer step is improved. The toner image whose charge has been discharged by the charge removing lamp 16 is transferred to the transfer material 18 at the transfer position T under the action of the transfer charger 17. The transferred transfer material 18 is neutralized by the neutralization charger 19 and is easily separated from the photoconductor 12.

After the transfer material 18 is separated, the photoconductor 12 is
, And the remaining charge is removed by the charge removing lamp 22 to return to the initial state, and the process proceeds to the next copying process, for example, the next separated color image forming process.

The transfer material 18 is stored in a paper feed cassette 23 and fed one by one by a first paper feed roller 24. The fed transfer material 18 is conveyed by a first guide 25, a second feed roller 26, and a second guide 27, and moves to a transfer start position S, which is a position slightly upstream (upstream) in the paper feed direction from the transfer position T. Sent.

The leading end of the transfer material 18 sent to the transfer start position is gripped and supported by a transfer material transport body 28, for example, a support portion 29 of the transfer material carrier, for example, a gripper 29.

At the start of the copying operation, the transfer material carrier 28 is located near the transfer start position S of the photoreceptor 12, and grips the leading end of the transfer material 18 conveyed from the paper feed cassette 23 to stand by. The transfer material carrier 28 synchronizes with the rotation of the photoconductor 12 and
12 The tip of the upper toner image is linearly moved at a timing suitable for transfer so that the tip of the upper toner image exactly matches the tip of the transfer material 18, and the transfer material 18 is moved to the left of the drawing at the same linear velocity as the photosensitive member 12. Pull and move.

The movement stroke of the transfer material carrier 28 is set to be substantially equal to the length of the transfer material 18, and when the length of the transfer material 18 changes, the movement stroke of the transfer material carrier 28 can be changed.

The transfer of one image is completed by moving the transfer material carrier 28 to the left in the drawing by a predetermined stroke, and the transfer material carrier 28 is again moved to the transfer start position S for the next image transfer.
Return to near. At the time of return, the transfer material 18 is guided substantially horizontally by the guide member 48 and retreats. A second guide 27 for transporting the transfer material 18 from the paper cassette 23 and a second guide 27
The paper feed roller 26 is retracted below the moving path of the transfer material 18 so as not to prevent the transfer material 18 moving backward.

From the transfer start position S, the transfer material 18 is synchronously moved in accordance with the movement of the next image to be over-transferred on the photoconductor 12, and the next image is over-transferred onto the previous image.

During the transfer of the last image of the predetermined number of images, the transfer material carrier 28 is moved by the grip release member 30 at the release position in the process of moving to the left in the drawing.
Gripper 29 is in the grip release state. At this time, the transfer material is located on the transport belt device 31. The transport belt device 31 includes a first transport roller 32 and a second transport roller 33 supported by a frame that can be tilted up and down around the axis of the first transport roller 32, and a transport belt wound around the transport rollers 32 and 33. 34 and transfer material 18 to transfer the transfer material 18 stably
And a suction member 35 for sucking 18. Conveyor belt
An opening row is provided in the opening row, and air is sucked through the opening row, so that the transfer material 18 is adsorbed by the transport belt 34 and transported in a stable state.

The conveying belt device 31 is made as short as possible in order to make the image forming apparatus, for example, a copying apparatus as small and compact as possible. For example, the smallest size transfer material 18 that can form an image
When the rear end of the transfer member 18 has passed the transfer position T of the photoreceptor 12 and the transfer has been completed, the leading end position of the transfer material 18 reaches near the end position of the transport belt device 31, and the grip release member 30 The gripping of the transfer material 18 can be released at a position slightly deviated to the left in FIG. 1 from the end.

Since the transfer material 18 needs to have at least the rear end positioned substantially at the transfer position T for each image transfer, in the case of a large-size transfer material 18, the transfer material carrier 28 is provided by a transport belt device.
A position far away from 31 (for example, position 2 shown by a chain line in the figure)
The stroke will be extended to 8 '). At this time,
A transfer material guide plate 36 is provided to support and guide a portion of the transfer material 18 that has deviated from the transport belt device 31. When the transfer material carrier 28 reciprocates with a long stroke, the gripper 29 is not released during the movement. As grip release member 30
Performs an appropriate processing, such as enabling the movement to an appropriate position, or providing a release movement preventing means without moving the position.

When the transfer of the predetermined number of images is completed, the transfer material 18 separated from the photoreceptor 12 is guided to a fixing device 37 to be fixed.

The fixing device 37 is provided so that the transfer material carrier 28 and the transfer material 18 do not hinder the reciprocating movement of each image, and that the transfer material 18 having a small size can be transported as short as possible. At a position distant from the reciprocating path of the carrier 28, for example, at an upper position, the conveyor belt device 31
Placed as close as possible to

At the point when the grip of the transfer material carrier 28 by the gripper 29 is released by the grip release member 30 at the end of the transfer material 18 on which the transfer of the predetermined number of images has been completed, the transport belt device 31 is moved to the center axis of the first transport roller 32. , The frame is tilted around, for example, the position F indicated by the chain line
To rise. The leading end of the transfer material 18 is completely separated from the gripper 29 of the transfer material carrier 28 by the elevation of the transport roller 33.

In the case of the transfer material 18 having a large size, even if the transfer material 18 is released from the gripping of the transfer material carrier 28, the transfer is continued at the rear portion, so that the transfer material 18 is transported by the transport belt 34 so that the transfer material 18 does not stop halfway. It is convenient to continue.
The transfer is completed by moving the transfer material carrier 28 supporting the transfer material 18 toward the left position 28 'in the figure until the rear end of the large transfer material 18 passes the transfer position T. After that, the grip release member 30 can be returned to a position where it can be conveniently driven.

The transfer material 18 transported by the transport belt device 31 tilted to the position F is fixed through the fixing device 37, and a permanent multiple transfer image is formed.

The multiple-copy image is not necessarily limited to a multi-color transfer image of a separated color image of a color original, and can be adapted to transfer an appropriate large number of images in an overlapping manner.

In the case of performing single-color copying by the apparatus shown in FIG. 1, the transfer material carrier 28 is retracted to a position outside the conveyor belt device 31, and the conveyor belt device 31 is set in a state of being tilted to the position F. It is possible to perform high-speed continuous copying in the same manner as described above.

After forming the electrostatic latent image on the photoreceptor 12, it is convenient to reduce the electric charge in the image area by the eraser 38 to prevent the black frame from being formed and to minimize the toner consumption. The eraser 38, which is a light source for preventing a black frame, is useful when enlarging and reducing an original image and recording the image, particularly at the time of reduction. The eraser 38 can also be used for erasing unnecessary portions of a document image.

When the transfer material 18 is reciprocated during multiple transfer by the transfer material carrier 28, the rear end of the transfer material 18 is not supported by anything and is in a free state. The transfer belt 34 is operated and the transfer material carrier 28 is moved.
It is desirable to be reciprocated in synchronization with the reciprocation of.

As shown in FIG. 2, a second paper feed path is provided outside the first paper feed roller 24 and the second paper feed roller 26 in the paper feed path of the transfer material 18 from the paper feed cassette 23 to the transfer start position S. A registration roller 40 can be provided between the roller 26 and the photoconductor 12, and a third guide plate 47 can be provided between the registration roller 40 and the transfer start position. Further, the second paper feed roller 26 and the registration roller 40 can be omitted, and the first paper supply roller 24 can be used as a registration roller. Conversely, the number of paper feed rollers can be further increased. The number of paper feed rollers is determined based on the arrangement for conveniently transporting the transfer material to the transfer position. Usually, the paper feed roller closest to the transfer position is used as a registration roller.

The first paper supply roller 24 is formed so as to be movable between a paper supply position pressed against the transfer material 18 and a standby position away from the transfer material 18. The second paper supply roller 26 and the registration roller 40 are a pair of rollers. And the second paper feed roller 26 is
Meanwhile, one of the registration rollers 40 is supported by a lever 42, and the lever 41 is rotatably supported around a fulcrum 43 and the lever 42 is rotatably supported around a fulcrum 44. A plunger of a solenoid 45 is pivotally attached to the lever 41, and a plunger of a solenoid 46 is pivotally attached to the lever 42. When the solenoids 45 and 46 are urged, the second paper feed roller 26 and the registration roller 40 are released from pressure contact. Then, when the solenoids 45 and 46 are deenergized, the second paper feed roller 26 and the registration roller 40 are switched to the paper feed state where they are pressed against each other. It should be noted that the deenergization and the energization of the solenoids 45 and 46 can be set to the opposite states.

When the first paper feed roller 24 and the second paper feed roller 26 are pressed and brought into a paper feed state, the transfer material is fed from the paper feed cassette 23, and the leading end of the transfer material 18 becomes the leading end of the toner image on the photoconductor 12. The registration roller 40
Is switched to the press-contact state to feed paper. When multiple transfer is performed, the registration roller 40 is switched to the pressed state at a timing such that the gripper 29 of the transfer material carrier 28 waiting at the transfer start position S can grip the transfer material 18 conveniently.

After the leading end of the transfer material 18 is gripped by the gripper 29 of the transfer material carrier 28, the first paper supply roller 24, the second paper supply roller 26, and the registration roller 40 are released from the pressure contact state and switched to the standby state, The transfer material 18 can follow the movement of the transfer material carrier 28 without any load. Since the transfer material 18 is completely free except for being gripped by the gripper 29 of the transfer material carrier 28, the transfer material 18 can accurately follow the movement of the transfer material carrier 28. Therefore, the transfer material 18 is not displaced from the transfer material carrier 28, and the image is disturbed. The transfer between the first transfer image and the transfer positions of the toner images on the second and subsequent photosensitive members 12 in the multiple transfer is not performed. It is possible to prevent misalignment between them.

After the first transfer image, for example, a yellow image is transferred onto the transfer material 18 by the forward movement of the transfer material carrier 28, the transfer material carrier 28 is moved back for transferring the next image. At this time, a return guide plate 48 is provided so that the transfer material 18 is not returned along the second guide plate 27 or the third guide plate 47 but is returned substantially horizontally.

When the transfer material 18 is reciprocated by the reciprocating movement of the transfer material carrier 28 and the toner images formed on the photoconductor 12 are sequentially superimposed and transferred, a third process is performed to form a close contact state of the transfer material 18 with the photoconductor 12. As shown in the figure, a pressing member 39 is provided near the transfer position T or the transfer start position S.

The pressing member 39 is a plate-shaped presser supported rotatably on the support shaft 51.
52 and a solenoid connected to the presser 52 via a spring 53
54. When the solenoid 54 is urged, the bent tip 55 of the presser 52 rises, and the transfer material
The transfer material 18 is pressed toward the photoconductor 12 to increase the degree of adhesion of the transfer material 18 to the photoconductor 12. When solenoid 54 is de-energized,
In 52, the leading end 55 is lowered by the action of gravity, and the pressing on the transfer material 18 is released.

In the multiple transfer, when the transfer material 18 returns to the return guide plate 48 due to the backward movement of the transfer material carrier 28, the rear end of the transfer material 18 (the leading end at the time of the return movement) collides with the presser 52 and jams. When returning, the solenoid 54 is de-energized so as to prevent the occurrence of the pressure.

When the transfer to the transfer material 18 is started by the forward movement of the transfer material carrier 28 from the transfer start position S, the solenoid 54 is energized, and the leading end 55 of the presser 52 rises, and the transfer material is moved near the transfer position T. The transfer material 18 is brought into close contact with the surface of the photoconductor 6 at the transfer position T by pushing up the transfer material 18. This makes the photoconductor
The toner image is reliably transferred onto the surface 12.

When the leading end 55 of the presser 52 rises and presses the transfer material 18 against the photoconductor 12, the transfer material carrier 28 starts to move from the transfer start position S, and the gripper 29 of the original transfer material carrier 28
It is desirable to select the time when the degree of close contact between the transfer material 18 and the photosensitive member 12 due to the supporting force of the toner starts to decrease and the pressing force for transferring the image with high efficiency cannot be obtained. In this case, the transfer carrier 28
The transfer material 18 is pressed by the presser 52 at a position slightly shifted from the gripper 29 to the rear end side of the transfer material. When the transfer material 18 is pressed by the presser 52 at a position very close to the gripper 29, when the supporting force of the gripper 29 is weak, the transfer material 18 is displaced with respect to the gripper 29. Cause. Furthermore, the transfer material 18 is gripper 29
In some cases, it may cause a jam and cause a jam.

FIG. 4 shows an example in which the roller 56 is rotatably supported on the tip end portion 55 of the presser 52 in FIG. By using the rotatable roll 56, friction with the transfer material 18 is reduced. Although the solenoid 54 is directly connected to the presser 52,
A spring 53 may be used. The operation of the presser 52 by the solenoid 53 is exactly the same as in the example of FIG.

The pressing member can be formed as an eccentric cam 52 ', unlike the lever-shaped press shown in FIGS. 3 and 4. The transfer material 18 can be pressed or released by controlling the rotation angle of the eccentric cam 52 'around the shaft 51.

Further, as the pressing member, as shown in FIG. 6, a guide plate closest to the transfer position such as the second guide plate 27 or the third guide plate 47 can also be used. For example, the second guide plate 27 has an upper guide plate 27a and a lower guide plate 27b rotatably supported around a fulcrum 57, and the lower guide plate 27b has a solenoid 54
Are connected, and the upper guide plate 27a is urged by the solenoid 54.
Then, the distal end of the lower guide plate 27b rises, and falls by the deenergization of the solenoid 54. The upper guide plate 27
a acts to press the transfer material 18 against the photoconductor.

The transfer material carrier 28 is constructed, for example, as shown in FIGS. 7 and 8, and a base 58 is fixed to the base 58 on both side walls.
59 and 60.

The gripper 29 serving as the transfer material supporting member 29 includes an upper fingerboard 62.
And the lower fingerboard 63, the upper fingerboard 62 is made of a plate having high rigidity, the lower fingerboard 63 is formed of a plate having high elasticity, and the rear end portion is formed on the lower surface of the upper fingerboard 62 by caulking or the like. The upper end of the upper fingerboard 62 is elastically pressed against the front end of the upper fingerboard 62. The lower fingerboard 63 may be made of a metal plate such as a metal spring plate, a phosphor bronze plate, or a stainless steel plate, or may be made of an elastic polymer material such as polycarbonate, polyethylene, or polyester. The tip of the lower fingerboard 63 is formed as a finger 63a bent upward.

The tips of the upper fingerboard 62 and the lower fingerboard 63 are formed as finger parts 62a and 63a protruding in a comb shape as shown in FIG. 7, and a transfer material using the number, width and shape of the comb-like teeth is used. Depending on the type and size of the device and the structure of the device.

The gripper 29 is connected to and supported on a base 58 of the transfer material carrier 28 by two hinge members 61 so as to be vertically tiltable.

The hinge member 61 includes a first fixing plate 61a fixed to the base 58,
Second fixing plate 61b fixed to upper fingerboard 62 of gripper 29
And a pin 61c, and the first fixed plate 61a
And the second fixing plate 61b are connected to each other so as to be relatively rotatable.

At least one of the first fixed plate 61a and the second fixed plate 61b has a stop extending toward the counterpart member, for example, in the case of the first fixed plate 61a, a stop 64 extending toward the upper fingerboard 62, In the case of the second fixing plate 61b, a stopper 65 extending toward the base plate 58 is provided. By providing one or both of the stop portions 64 and 65, the gripper 29 sets the upper limit of the vertical tilting by the hinge member 61 when the upper fingerboard 62 is located substantially on the same plane as the base plate 58,
The upper fingerboard 62 can be tilted only in a range below the extension surface of the base plate 58. Therefore, the transfer material carrier side walls 59, 60
Cuts out the tilting range of the gripper 29 so that the gripper 29 does not come into contact, and provides a spring 66 between the side walls 59 and 60 and the vicinity of the rear end of the lower fingerboard 63 in the cutout member, and raises the gripper 29 upward. Press. The spring 66 holds the gripper 29 at an upper limit position which is usually flush with the base plate 58.

When the transfer material carrier 28 transports the transfer material 18 so as to be in contact with the photoconductor 12 at the time of transfer, even if the gripper 29 comes into contact with the photoconductor 12, the gripper 29 can be easily moved to the photoconductor 12.
Can be tilted downward to escape from the surface of the photoconductor 12, without giving excessive mechanical stimulation to the surface of the photoconductor 12, and the surface of the photoconductor 12 can be prevented from being damaged. Since damage cannot be avoided if the force of the spring 66 is too strong, the spring constant of the spring 66 is selected to a value that allows the gripper 29 to move without causing damage even if it comes into contact with the photoconductor 12.

For the multiple transfer, the transfer material carrier 28 is moved to the transfer start position S
When returning to the predetermined position, when the gripper 29 is tilted in a direction to separate the transfer material 18 from the photoconductor 12, a pressing member (not shown) can be provided. The pressing member 18 prevents the transfer material 18 from contacting the photoreceptor 12 so that the transfer material 18
It is possible to prevent the above unfixed toner image from being disturbed.

When the transfer material carrier 28 is located at the transfer start position, the lower fingerboard 63 of the gripper 29 is used to grip the leading end of the transfer material 18 fed from the paper feeding device 23 by the gripper 29.
A grip releasing member is provided to open only the finger portions of the upper fingerboard 62 and the lower fingerboard 63 by pulling down only the fingerboard. The grip release member is formed as a member that has a claw that engages with the lower fingerboard 63 and that is lowered by urging means such as a solenoid.
When the force by the urging means is removed, the pawl separates from the lower fingerboard 63, and the lower fingerboard 63 returns by its own elasticity and, if necessary, by the force of the spring 66 to close the finger and grip the leading end of the transfer material 18. I do. By the action of the grip release member, only the finger portion 63a at the tip of the lower fingerboard 63 is pushed down, but at this time, the force of the spring 66 and the lower fingerboard are suppressed so that the spring 66 is suppressed and the upper fingerboard 62 does not tilt down. Select the 63 relationship with elasticity. The grip release member 30 may have the same configuration as the grip release member.

A reinforcing plate 67 extending in a direction perpendicular to the moving direction D of the transfer material carrier 28 is fixed to the lower surface of the lower fingerboard near the finger portion 63a of the lower fingerboard 63, and the lower fingerboard 63 is opened by the grip release member. In this case, it is considered that the gap between the finger portion 62a of the upper fingerboard 62 and the finger portion 63a of the lower fingerboard 63 becomes uniform at any tooth and that the lower fingerboard 63 is reinforced. As shown in FIG. 7, both ends of the reinforcing plate 67 are exposed from the lower fingerboard 63, and the grip release members are engaged with both ends of the reinforcing plate 67 to push down the reinforcing plate 67, thereby lowering the lower fingerboard 63. It can also be tilted. The material, width, thickness, and mounting position of the reinforcing plate 67 are determined by the elasticity of the lower fingerboard 63, the gripping force of the upper fingerboard 62 and the lower fingerboard 63 on the transfer material 18, and the movement of the reinforcing plate 67 such as the transfer charger and the static elimination charger. Is determined by the positional relationship with each component located in the vicinity of the solenoid space.

The base portion 58 of the transfer material carrier 28 and the upper fingerboard 62 of the gripper 29 can be formed by using a resin material in a shape integrally connected by a connecting portion 68 as shown in FIG. 9A. . With this structure, a low-cost transfer material carrier can be manufactured. The reinforcing plate 67 may be formed of a resin material integrally with the lower fingerboard 63a.

The connecting portion 68 can be formed to perform the function of the hinge 61 and the spring 66 in the example of FIGS. 7 and 8. In that case ninth
As shown in FIG. B, the upper fingerboard 36 tilts downward due to the bending of the connecting portion 68, and strong contact with the photoconductor 12 can be prevented. In order for the connecting portion 68 to have a hinge action and a spring action,
As the resin material, fiber reinforced plastics such as glass fiber, carbon fiber, metal fiber, and Saramix fiber are preferable.

Gripper of transfer material carrier 28 at transfer start position S
When the transfer material 18 fed to the transfer material 29 enters the transfer material, or when the transfer material carrier moves to the transfer material whose positioning is stopped, the transfer material enters the gripper 29 to grip the transfer material. However, when it is necessary to stop the leading end of the transfer material at a fixed position in order to determine the grip width of the leading end portion of the transfer material by the gripper 29, a stopper 69 is provided near the transfer start position S as shown in FIG. Can be provided.

When the transfer material 18 is reciprocated by the transfer material carrier 28 for the multiple transfer, if there is a charge in the previously transferred toner image, the transferability may be deteriorated at the time of transferring the next image. In order to remove this and improve the multiple transfer property, a transfer material discharging member 70, for example, a discharging charger is provided above the return guide plate 48, which is a return path of the transfer material 18, as shown in FIGS.
It can be provided as shown in the figure. Transfer material static elimination member 70
Removes the charge of the toner forming the toner image transferred to the transfer material 18 and the charge of the background portion other than the toner image. Transfer material discharging member 70 is typically an AC corona discharge electrodes are used, 4000～10000V, driving bias 50～200H _Z is applied.

〔effect〕

According to the present invention, since transfer resistance is prevented from being imparted to the transfer material, the transfer material is reliably transported by the transfer material transport body, so that transportability is improved and adhesion to the latent image carrier is maintained.

[Brief description of the drawings]

FIG. 1 is an overall schematic explanatory view of a multi-color copying machine as an example of an image forming apparatus according to the present invention, FIG. 2 is an explanatory view of an example of a transfer material feeding means from a sheet feeding device to a transfer position, and FIG. Is an illustration of an example of a pressing member for the transfer material and the vicinity of the latent image carrier,
FIG. 4 to FIG. 6 are explanatory views of modified examples of the pressing member, and FIG.
FIG. 8 is a perspective view of the transfer material transporter, FIG. 8 is a side view, and FIG. 9 is a modified example of the transfer material transporter. 12 ... Latent image carrier, 15 ... Developer 17 ... Transfer charger, 18 ... Transfer material 23 ... Sheet feeding device, 24, 26 ... Sheet roller pair 28 ... Transfer material transporter, 29 ... Transfer material support 40 ... Supply Paper roller pair (registration roller) 52 ... Pressing member

Claims (1)

(57) [Claims] A latent image carrier, a developing device for developing the latent image, and a transfer material transporter which can reciprocate linearly in a tangential direction of the latent image carrier at a transfer section; In a multiplex image forming apparatus for transferring a plurality of toner images sequentially formed on an image carrier onto a transfer material that is supported by the transfer material transporter and reciprocated and transported, the transfer material transporter includes a transfer material transporter. And a transfer material support portion, at least the transfer material support portion of the transfer material transporting body is disposed in the paper feed path at a transfer start position slightly upstream in the transfer material feed direction from the transfer position by the latent image carrier. After supporting the transfer material fed by the pair of feed rollers, each of the feed roller pairs feeds at least until the rear end of the transfer material passes after the transfer material starts to move for transfer. A multiplex image forming apparatus, which is held in a release state.