JP2001356619A - Transfer device - Google Patents

Abstract

(57) [Problem] To reliably transfer a transfer roller in a transfer device. SOLUTION: An intermediate transfer belt 7 on which a toner image is formed
The transfer roller 10 is pressed by the intermediate transfer belt 7 to transfer the toner image to the print paper by nipping and transporting the print paper.
A cleaning roller 18 that comes into contact with the surface of the transfer roller 10 to clean the surface of the transfer roller 10, a transfer roller swinging plate 11 that holds the transfer roller 10 so as to be detachable from the intermediate transfer belt 7, A roller 18 is detachably attached to the transfer roller 10, and holds the cleaning roller 18 in contact with the transfer roller 10 in conjunction with the separation operation of the transfer roller rocking plate 11. And a cleaning rocking plate 21 that separates the transfer roller 10 from the transfer roller 10.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a transfer device used in an electrophotographic copying machine or a printer, and more particularly to a transfer device for transferring a toner image formed on a belt-like transfer member onto a printing paper by using a transfer roller. And a transfer device.

[0002]

2. Description of the Related Art A conventional transfer device will be described below.

FIG. 8 is an explanatory view showing a conventional transfer apparatus, FIG. 9 is a perspective view showing a main part of the transfer apparatus in FIG. 8, and FIG.
FIG. 11 is an enlarged plan view showing a part of the transfer device of FIG.
Is a cross-sectional view taken along the line BB of FIG. 10, and FIG. 12 is an explanatory view showing a conventional transfer device moved to a position different from that of FIG.

In an image forming apparatus provided with a conventional transfer device, for example, four developing device housings are arranged, and each developing device housing has a drum-shaped photosensitive member formed of a dielectric material and rotating at a constant speed. Is provided. Around the photoreceptor, a charger for uniformly charging the surface of the photoreceptor, an exposure device for irradiating an exposure light beam to form an electrostatic latent image on the photoreceptor, and a developing device for visualizing the electrostatic latent image A cleaning blade for removing the toner remaining on the photoconductor after the transfer of the toner image, and a static eliminator for removing the charge remaining on the photoconductor after the transfer of the toner image are arranged.

In the developing device housing, a yellow image, a magenta image, a cyan image, and a black image are formed, respectively.

Below the photoconductor, an endless intermediate transfer belt 7 (FIG. 8) is provided in contact with the photoconductors arranged in a line. The photoconductor is in contact with the intermediate transfer belt 7 at a portion downstream of the developing device in the rotation direction. A cleaner for cleaning the surface of the intermediate transfer belt 7 is provided upstream of the intermediate transfer belt 7 in the rotation direction from the photoconductor.

Below the intermediate transfer belt 7, a printing paper cassette is provided. Then, on a paper transport path starting from the print paper cassette, a paper feed roller that picks up the print paper stored in the print paper cassette one by one and guides the print paper to the paper transport path, and toner formed on the intermediate transfer belt 7. A registration roller for temporarily stopping and waiting the printing paper in order to take a timing for transferring the image to the printing paper;
A transfer roller 10 for transferring a toner image on the intermediate transfer belt 7 to a print sheet is arranged (see FIG. 1).

[0008] As shown in FIG.
A cleaning roller 18 for cleaning the toner adhered to the transfer roller 10 by a potential gradient is in contact.

The transfer roller 10 is rotatably supported at one end of a transfer roller swinging plate 11 and is driven to rotate in synchronization with the intermediate transfer belt 7. Transfer roller rocking plate 11 is shaft 1
2, the other end of which is provided with a spring 36 which presses and biases the transfer roller swing plate 11 against the cam 13.
Is attached.

The cam 13 has a projection 13a for separating the transfer roller 10 from the intermediate transfer belt 7, and a recess 13b for bringing the transfer roller 10 into contact with the intermediate transfer belt 7. Attached to.

As shown in FIGS. 9 to 11, a half-turn clutch 17 is attached to one end of the shaft 14 by inserting the shaft 14 into a cylindrical rotary shaft 17a. As a result, the rotation shaft 17a of the half-turn clutch 17 and the cam 13 and the shaft 14
And rotate synchronously.

The half-turn clutch 17 has a cylindrical rotary shaft 17a.
The outer periphery of the rotating plate 42 has two locking portions 42a and 42b formed at positions opposite to each other with respect to the center of rotation, and the outer periphery of the cylindrical rotating shaft 17a can be moved in the axial direction. A slider 19 having a locking portion 19a is incorporated. The half-rotation clutch 17 has a drive gear 20 for rotating the rotation shaft 17a.

Next, the operation from the operation of the half-turn clutch 17 to the operation of the transfer roller 10 will be described with reference to FIGS.

When the half-turn clutch 17 is energized, the slider 19 is attracted and moves in the direction of the arrow m shown in FIG. As a result, the locking portion 42a of the rotating plate 42 is released from the locking portion 19a of the slider 19, and the rotating plate 4
2 rotates 180 degrees. Then, the slider 19 is energized o
The locking portion 19a that has moved in the direction of arrow n at ff and returned to the original position is engaged with the locking portion 42b of the rotating plate 42, and the rotating plate 4
2 is stopped. The shaft 14 and the cam 13 together with the cylindrical rotary shaft 17a of the half-turn clutch 17
Stop after rotating by 80 degrees.

Next, when the half-rotation clutch 17 is energized, the slider 19 is sucked, and is sucked in the direction of arrow m, so that the locking portion 42b of the rotating plate 42 is locked by the locking portion 1 of the slider 19.
9a, the rotating plate 42 rotates 180 degrees. Locking portion 1 of slider 19 returned to original position by energization off
At 9a, the locking portion 42a of the rotating plate 42
The rotation of is stopped. The shaft 14 and the cam 13 together with the cylindrical rotary shaft 17a of the half-turn clutch 17
Stop by rotating 0 degrees.

When the locking portion 42a of the rotary plate 42 of the half-rotation clutch 17 engages with the locking portion 19a of the slider 19, the convex portion 13a of the cam 13 pushes down the transfer roller rocking plate 11 of the transfer roller 10 to the maximum. The transfer roller 10 is separated from the intermediate transfer belt 7 (FIG. 12).

When the locking portion 42b of the rotary plate 42 of the half-rotation clutch 17 is engaged with the locking portion 19a of the slider 19, the recess 13b of the cam 13 faces the transfer roller swing plate 11 of the transfer roller 10. In this position, the transfer roller 10 is disposed so as to contact the intermediate transfer belt 7 (FIG. 8).

Here, the cleaning device B (FIG. 8)
A cleaning roller 18 that removes toner and paper dust from the surface of the transfer roller 10 using a potential gradient, and a cleaning roller 18 attached to a cleaning frame 19.
And a cleaning blade 20 that is pressed against the cleaning roller 18 and removes toner and paper dust attached to the cleaning roller 18. The cleaning roller 18 and the cleaning frame 19 are mounted on a cleaning roller rocking plate 21 that is pivotally supported by a fulcrum 21 a and presses and separates the cleaning roller 18 from and to the transfer roller 10.

The operation of the conventional transfer device thus configured will be described with reference to FIGS.

A latent image of yellow component color, which is image data, is formed on a photoreceptor by a known electrophotographic process means using a charger, an exposure device and the like. After that, the image is visualized as a yellow toner image by a developing material having the yellow toner in the developing device, and the yellow toner image is transferred to the intermediate transfer belt 7.

On the other hand, a latent image of the magenta component color is formed while the yellow toner image is being transferred to the intermediate transfer belt 7, and the magenta toner image by the magenta toner is visualized by the developing device. The yellow toner image transferred on the belt 7 is superimposed.

Thereafter, image formation is performed in the same manner for the cyan toner image and the black toner image. When the superposition of the four color toner images on the intermediate transfer belt 7 is completed, the transfer rollers 10 The color toner images are collectively transferred, and a full-color image is obtained.

Next, the operation when a toner image is transferred to the printing paper 8 will be described.

Before the first color (here, yellow) is transferred to the intermediate transfer belt 7, the transfer roller 10 is pressed against the intermediate transfer belt 7 with the cleaning roller 18 pressed against the transfer roller 10. 7 and is rotating.

The printing paper stored in the printing paper cassette is sent out one by one from the printing cassette by a paper feed roller. The sent printing paper is an intermediate transfer belt 7.
It is stopped and waited in order to match the toner images formed thereon. When the intermediate transfer belt 7 arrives at a predetermined position, the printing paper that has been waiting reaches the contact position between the transfer roller 10 and the intermediate transfer belt 7, and a polarity opposite to the charging polarity of the toner is applied as a transfer bias. 4 which is sandwiched between the transfer roller 10 and the intermediate transfer belt 7 and synthesized with the intermediate transfer belt 7
The color toner image is transferred to the printing paper. At this time, the cleaning roller 18 comes into contact with the transfer roller 10 and is driven to rotate with respect to the transfer roller 10.

Here, when the transfer roller 10 is contaminated with toner due to paper jam, printing paper of inappropriate size, or the like, the toner adhering to the transfer roller 10 is electrostatically charged to the cleaning roller 18 by a potential gradient. Attached. The toner adhered to the cleaning roller 18 is scraped off by the cleaning blade 20 and collected in a waste toner box (not shown). When the transferred printing paper passes through the holding portion between the transfer roller 10 and the intermediate transfer belt 7, the half-rotation clutch 17 rotates the rotary shaft 17a, the shaft 14, and the cam 13 by 180 degrees by the drive gear 20. As a result, the transfer roller rocking plate 11 is
The transfer roller 10 is moved away from the intermediate transfer belt 7 by the convex portion 13a, and stands by in a non-transfer state shown in FIG.

Since the projection 21b of the cleaning roller rocking plate 21 is pressed by the transfer roller rocking plate 11, the cleaning roller 18 is displaced about the shaft 21a and separated from the transfer roller 10.

[0028]

As described above, the cleaning of the transfer roller 10 is performed while the transfer roller 10 is always in contact with the intermediate transfer belt 7.
0 may be contaminated again by residual toner on the intermediate transfer belt 7. Therefore, there is a problem that cleaning of the surface of the transfer roller 10 becomes insufficient.

When the transfer roller 10 is separated from the intermediate transfer belt 7 after passing the transfer position of the printing paper, the transfer position between the cleaning roller 18 and the transfer roller 10 is changed from the contact position between the intermediate transfer belt 7 and the transfer roller 10. There is a problem that the surface m of the transfer roller 10 in the section cannot be cleaned.

Accordingly, an object of the present invention is to provide a transfer device capable of reliably cleaning a transfer roller.

[0031]

In order to solve this problem, a transfer device according to the present invention is pressed by an intermediate transfer belt on which a toner image is formed, and nips and conveys printing paper with the intermediate transfer belt to transfer toner. A transfer roller for transferring an image to printing paper, a cleaning member that contacts the surface of the transfer roller and cleans the surface of the transfer roller, and a transfer roller holding member that holds the transfer roller detachably from the intermediate transfer belt. ,
A cleaning member is detachably attached to the transfer roller, and holds the cleaning member in contact with the transfer roller in conjunction with the separation operation of the transfer roller holding member,
Thereafter, a cleaning member holding member for separating the cleaning member from the transfer roller is provided.

Thus, since the transfer roller is cleaned without being affected by the intermediate transfer belt, the transfer roller can be reliably cleaned.

[0033]

DESCRIPTION OF THE PREFERRED EMBODIMENTS According to the first aspect of the present invention, the toner is pressed against an intermediate transfer belt on which a toner image is formed.
A transfer roller that nips and conveys the printing paper with the intermediate transfer belt to transfer the toner image to the printing paper; a cleaning member that contacts the surface of the transfer roller and cleans the surface of the transfer roller; A transfer roller holding member that holds the transfer member detachably, and a cleaning member that is detachably attached to the transfer roller, and the cleaning member contacts the transfer roller in conjunction with the separation operation of the transfer roller holding member. And a cleaning member holding member that separates the cleaning member from the transfer roller, and then cleans the transfer roller without being affected by the intermediate transfer belt. This has the effect that cleaning can be performed quickly.

According to a second aspect of the present invention, in the first aspect of the present invention, the transfer roller is rotated by abutting on the transfer roller holding member, and the transfer roller holding member is swung to move the transfer roller to the intermediate transfer belt. A cam member for separating and contacting, a biasing unit for biasing the cleaning member to the transfer roller, and a biasing unit for biasing the transfer roller to the intermediate transfer belt; the cam member includes a transfer roller holding member. When the transfer roller is moved to a position where the transfer roller is brought into contact with the intermediate transfer belt, the cleaning member is brought into contact with the transfer roller, and when the transfer roller holding member is moved to a position where the transfer roller is separated from the intermediate transfer belt, the cleaning member is brought into contact with the transfer roller. When the transfer roller holding member moves further away from the intermediate transfer belt, the cleaning member swings in the direction opposite to the transfer roller when the transfer roller holding member moves further away from the intermediate transfer belt. A transfer device for separating the cleaning member from the transfer roller, an effect that since so as to clean the transfer roller without the influence of the intermediate transfer belt, it is possible to reliably clean the transfer roller.

According to a third aspect of the present invention, in the first or the second aspect of the present invention, the cleaning member holding member includes a projection member for separating the cleaning member from the transfer roller, and a swing member of the cleaning member holding member. Since the transfer device is disposed between the fulcrum and the contact point between the transfer roller and the cleaning member, the transfer roller is cleaned without being affected by the intermediate transfer belt.
This has the effect that the transfer roller can be reliably cleaned.

According to a fourth aspect of the present invention, in the first or second aspect of the present invention, the transfer roller holding member includes an elastic member for rotating the cleaning member holding member with respect to a fulcrum of the cleaning member holding member. Since the transfer device is provided to clean the transfer roller without being affected by the intermediate transfer belt, the transfer device has an effect that the transfer roller can be reliably cleaned.

Hereinafter, an embodiment of the present invention will be described with reference to FIG.
This will be described with reference to FIG. In these drawings, the same members are denoted by the same reference numerals, and duplicate description is omitted.

FIG. 1 is an explanatory view showing an image forming apparatus to which a transfer device according to an embodiment of the present invention is attached, and FIG.
Is an explanatory diagram showing a transfer device in the image forming apparatus of FIG. 1;
3 is an explanatory diagram showing the transfer device moved to a position different from that in FIG. 2, FIG. 4 is an explanatory diagram showing the transfer device moved to a position different from FIGS. 2 and 3, and FIG. 5 is a transfer in the image forming apparatus in FIG. FIG. 6 is a perspective view showing the apparatus, FIG. 6 is a perspective view in which a transfer roller is omitted from FIG. 5, and FIG. 7 is an explanatory view showing the operation of the transfer apparatus in the image forming apparatus shown in FIG.

As shown in FIG. 1, the color image forming apparatus has four developing device housings 28a, 28b, 28c, 2
8d are arranged, and each developing unit housing 28a, 28b,
28c and 28d have an organic photoconductor (OP) on the outer peripheral surface.
The photosensitive member 1 is a drum-shaped photosensitive member 1 which is an electrostatic latent image carrier which is coated with a photosensitive receiving layer such as C) and rotates at a constant speed in the direction of arrow a. Around the photoreceptor 1, a charger 2 for uniformly charging the surface of the photoreceptor 1, an exposure device 3, which is a scanning optical system for irradiating the photoreceptor 1 with an exposure light beam 3a to form an electrostatic latent image, A developing device 4 for visualizing the electrostatic latent image, a cleaning blade 5 for removing toner remaining on the photoconductor 1 after transfer of the toner image, and an electric charge remaining on the photoconductor 1 after transfer of the toner image The static eliminators 6 are respectively arranged along the rotation direction of the photoconductor 1.

Here, the developing device 4 is rotatably mounted on a toner stirring member 29 for stirring and transporting the toner charged in the developing device 4 and on the developing device housings 28a, 28b, 28c, 28d. 1 and a developing roller 30 for developing an electrostatic latent image by adhering toner, and also rotatably attached to developing device housings 28a, 28b, 28c and 28d and rotating together with a toner stirring member 29, A developer supply member (hereinafter, referred to as a developer supply member) that supplies the toner agitated and conveyed by 29 to the surface of the developing roller 30
It is called "toner supply roller". ) 27, and a toner thinning blade 31 formed of urethane, silicon, or the like, which thins the toner supplied on the outer peripheral surface of the developing roller 30 by the toner supply roller 27 and frictionally charges the toner to a predetermined potential. Have been.

The developing device housings 28a, 28b,
At 28c and 28d, a yellow image, a magenta image, a cyan image, and a black image are formed, respectively.
An exposure light beam 3a, which is a scanning light beam corresponding to the black image, is output.

Below the photoreceptor 1, an endless intermediate transfer belt 7, which is band-adjusted by rollers 32a, 32b, and 32c rotating in the direction of arrow b and rotates in synchronization with the photoreceptor 1, is provided.
The photoconductors 1 are provided in contact with the photoconductors 1 arranged in a line. The photoconductor 1 is in contact with the intermediate transfer belt 7 at a portion downstream of the developing device 4 in the rotation direction.

A cleaner 9 for cleaning the surface of the intermediate transfer belt 7 is provided upstream of the intermediate transfer belt 7 in the rotation direction with respect to the photoconductor 1.

Below the intermediate transfer belt 7, printing paper 8
A printing paper cassette 24 for storing the printing paper is provided. The printing paper 8 stored in the printing paper cassette 24 is placed on the paper transport path starting from the printing paper cassette 24.
Paper feed rollers 22 and 23 for picking up the sheets one by one and guiding them to the sheet transport path, and temporarily transferring the print sheet 8 to the transfer sheet 8 in order to transfer the toner image formed on the intermediate transfer belt 7 to the print sheet 8. Registration roller 2 for stopping and waiting
5. Pinch roller 2 pressed against registration roller 25
6, a transfer roller 10 that rotates in the direction of arrow c and transfers the toner image on the intermediate transfer belt 7 to the printing paper 8 fed by the registration roller 25 is disposed. Further, a cleaning roller (cleaning member) 18 for cleaning the toner adhered to the transfer roller by a potential gradient is in contact with the transfer roller 10.

In the color image forming apparatus having the above-described structure, first, in the developing device housing 28a, the yellow electrophotographic image data is formed on the photoreceptor 1 by a known electrophotographic process means using the charger 2 and the exposure device 3. A latent image of the component color is formed. Thereafter, the developing device 4 visualizes the yellow toner image as a yellow toner image with a developing material having the yellow toner, and the yellow toner image is transferred to the intermediate transfer belt 7.

On the other hand, while the yellow toner image is being transferred to the intermediate transfer belt 7, a magenta component color latent image is formed in the developing device housing 28 b, and the magenta toner image of magenta toner is And is superposed on the yellow toner image previously transferred on the intermediate transfer belt 7.

Thereafter, image formation is performed in the same manner for the cyan toner image and the black toner image. When the superposition of the four color toner images on the intermediate transfer belt 7 is completed, the printing paper is fed by the paper feed rollers 22 and 23. The transfer roller 10 collectively transfers the four color toner images onto the printing paper 8 fed from the cassette 24, and a full-color image is obtained on the printing paper 8.

Each of the photosensitive members 1 whose transfer has been completed
The toner remaining on the photoreceptor 1 is removed by the cleaning blade 5, and the residual charge on the photoreceptor 1 is removed by the charge remover 6, and the printing operation is completed in preparation for the next image formation.

A color image is obtained as described above.

A one-way clutch gear 34 (FIG. 5) is attached to the other end of the transfer roller 10, and a portion upstream of the contact point between the intermediate transfer belt 7 and the photosensitive member 1 in the rotation direction of the intermediate transfer belt 7. It is arranged in.

As shown in FIGS. 2 to 4, the transfer roller 10
Is rotatably supported by a transfer roller rocking plate (transfer roller holding member) 11. The transfer roller rocking plate 11 is swung about a shaft 12 as a fulcrum. A cam (cam member) 13 for attaching and detaching the intermediate transfer belt 10 to and from the intermediate transfer belt 7 is attached. The cam 13
A protrusion 13 a for separating the transfer roller 10 from the intermediate transfer belt 7 and a recess 13 b for contacting the transfer roller 10 with the intermediate transfer belt 7 are formed and attached to the shaft 14. The other end of the shaft 14 has a 1/3 rotation clutch 3
5 (FIG. 6) is attached. At the other end of the transfer roller swinging plate 11, a spring (biasing means) 36 for biasing the transfer roller swinging plate 11 against the cam 13 is provided.

The 1/3 rotation clutch 35 has three locking portions 38a, 38 formed at an angle of 90 degrees from the center of rotation.
b, 38c, and a slider 3 having a locking portion 37a movable in the axial direction of the rotating shaft of the rotating plate 38.
7 is built-in.

Next, the relationship between the 1/3 rotation clutch 35 and the cam 13 will be described with reference to FIG.

When the ３ rotation clutch 35 is energized, the slider 37 is attracted and the locking portion 38
a is released from the locking portion 37a of the slider 37, and the rotating plate 38 is moved together with the rotating shaft 17a, the shaft 14,
Rotate 0 degrees. Then, the engaging portion 37a of the slider 37 and the engaging portion 38b of the rotating plate 38 which are moved in the opposite direction by the energization off and return to the original position are engaged, and the rotating plate 38,
The rotation of the rotating shaft 17a, the shaft 14, and the cam 13 is stopped.
Then, the shaft 14 and the cam 13 rotate 180 degrees together with the cylindrical rotation shaft of the 1/3 rotation clutch 35 and stop (FIG. 7A).

Next, the 1/3 rotation clutch 35 is turned on.
Then, the slider 37 is sucked, and the locking portion 38b of the rotating plate 38 is released from the locking portion 39a of the slider 37,
The rotating plate 38 rotates 90 degrees. The locking portion 37c of the rotating plate 38 is engaged with the locking portion 37a of the slider 37 that has returned to the original position by the energization off, and the rotation of the rotating plate 38 is stopped.
Then, the shaft 14 and the cam 13 together with the cylindrical rotary shaft of the 1/3 rotary clutch 35 rotate 90 degrees and stop (FIG. 7).
(B)).

Finally, the 1/3 turn clutch 35 is energized o
Then, the slider 37 is sucked, the locking portion 38c of the rotating plate 38 is released from the locking portion 37a of the slider 37, and the rotating plate 38 rotates 90 degrees together with the rotating shaft 17a, the shaft 14, and the cam 13. . Then, the engaging portion 3 of the slider 37 that has been moved in the opposite direction by the energization off and returned to the original position.
7a and the locking portion 38a of the rotating plate 38
The rotation of 8 is stopped. And 1/3 turn clutch 35
The cylindrical rotary shaft, shaft 14, and cam 13 rotate 90 degrees and stop (FIG. 7C). Thus, the cam 13 makes one rotation.

As shown in FIGS. 2 to 4, the transfer roller 10
Is provided with a cleaning roller 18 that rotates in contact with the transfer roller 10 and electrostatically removes toner attached to the transfer roller 10 by a potential gradient. Further, the cleaning roller 18 is attached to the cleaning frame 19 and is pressed against the cleaning roller 18 so that the cleaning roller 18
A cleaning blade 20 is provided for removing toner and paper dust attached to the image forming apparatus. The cleaning roller 18 and the cleaning frame 19 are attached to a cleaning rocking plate (cleaning member holding member) 21. Below the cleaning frame 19, the cleaning blade 20 adheres to the cleaning roller 18.
A waste toner box 39 for collecting the toner scraped off by this is disposed.

Here, the cleaning roller rocking plate 21 rotatably holds the cleaning roller 18 and is inserted into a waste toner box 39 fixed to the main body side in a snap manner by using resin elasticity. It is detachably and rotatably mounted. The cleaning roller 18 is provided in the waste toner box 39 with the transfer roller 1.
A spring (biasing means) 40 for pressing to zero is stored.

Above the cleaning roller oscillating plate 21, the transfer roller oscillating plate 11 to which a leaf spring 41 oscillated by the cam 13 is fixed is located (FIG. 6). Then, a projection (projection member) 2 located between the fulcrum 21 a of the cleaning roller rocking plate 21 and the cleaning roller 18.
1b until the leaf spring 41 comes into contact with the cleaning roller 1
The transfer roller 8 and the transfer roller 10 move in a contact state (FIG. 2), and after the leaf spring 41 of the transfer roller rocking plate 11 comes into contact with the projection 21b (FIG. 3), the cleaning roller rocking plate 21 is moved to the transfer roller. The cleaning roller 1 is pushed down by the leaf spring 41 of the oscillating plate 11 and moves faster than the angular velocity of the transfer roller 10 around the fulcrum 21a of the cleaning roller oscillating plate 21 to thereby cause the cleaning roller 1 to move.
8 is separated from the transfer roller 10 and is separated (FIG. 4).

In FIG. 8, the cleaning roller rocking plate 21 to which the cleaning roller 18 and the cleaning blade 20 are attached is arranged to be inserted inside the U-shaped transfer roller rocking plate 11 in FIG. The protrusion for pushing down the cleaning roller rocking plate 21 attached to the transfer roller rocking plate 11 must be attached after the cleaning roller rocking plate 11 is inserted.
Poor workability. Therefore, if the projection is an elastic body such as the leaf spring 41 as in the present embodiment, the leaf spring 41 can be smoothly inserted even after the leaf spring 41 is attached to the transfer roller rocking plate 11. Good (Fig. 6, view H)
reference).

Next, the operation of the transfer roller 10 will be described.

Before the start of printing, as shown in FIG. 4, the rotation of the intermediate transfer belt 7 is stopped.
The transfer roller 10 separated by about 4 mm is waiting while receiving a driving force and rotating independently. At this time, the 1/3 rotation clutch 35 is stopped by the engagement of the engagement portion 38a of the rotating plate 38 with the engagement portion 37a of the slider 37, and the projection 13a of the cam 13 is This is pushed down to the maximum. Further, the protrusion 21 b of the cleaning roller rocking plate 21 is connected to the leaf spring 41 of the transfer roller rocking plate 11.
As a result, the cleaning roller 18 is kept away from the transfer roller 10 so that cleaning cannot be performed.

Next, when the intermediate transfer belt 7 starts rotating and several seconds before the transfer of the toner image from the photoreceptor 1 to the intermediate transfer belt 7 is started, the 1/3 rotation clutch 35 is energized for several tens of milliseconds. Thus, the slider 37 is sucked. Then, the locking portion 38 a of the rotating plate 38 is released from the locking portion 37 a of the slider 37, and the driving gear 20 rotates the rotating shaft 1.
7a, the shaft 14, and the cam 13 rotate 180 degrees. Energization of
The slider 3 moved in the opposite direction at f and returned to the original position
7 and the locking portion 38b of the rotating plate 38 are engaged, and the rotation of the rotating plate 38 is stopped. Then, the cylindrical rotary shaft 17a, shaft 14, cam 1 of the 1/3 rotary clutch 35
3 also rotates 180 degrees and stops.

Then, the concave portion 13b of the cam 13 faces the flat surface 11a of the transfer roller swing plate 11 (FIG. 6), and the transfer roller swing plate 11 swings around the shaft 12 in the direction of the intermediate transfer belt 7. The rotating transfer roller 10 is pressed against the intermediate transfer belt 7 by the intermediate transfer belt 7 by a spring 36,
The transfer roller 10 rotates following the intermediate transfer belt 7 to prepare for printing.

Next, the printing paper 8 that has been waiting is conveyed, and the toner image on the intermediate transfer belt 7 is transferred to the printing paper 8. At this time, the protrusion 21b of the cleaning roller rocking plate 21 is released from the leaf spring 41 of the transfer roller rocking plate 11, and the cleaning roller 18 is pressed and urged against the transfer roller 10 by the spring 40. As a result, the cleaning roller 18 is driven to rotate in the forward direction with respect to the transfer roller 10 to be in a state in which cleaning can be performed.

As shown in FIG. 3, when the printing paper 8 has passed the transfer roller 10 and the transfer of the toner image has been completed, the 1/3 rotation clutch 35 is energized for several tens of milliseconds, and the slider 37 is attracted. Then, the locking portion 38b of the rotating plate 38 is released from the locking portion 37a of the slider 37, and the rotating shaft 17a, the shaft 14, and the cam 13 are rotated by 90 degrees by the drive gear.
Then, when the power is turned off, the slider 37 moves in the opposite direction and returns to the original position, so that the locking portion 37a of the slider 37 and the locking portion 38c of the rotating plate 38 are engaged, and the rotation of the rotating plate 38 is stopped.
Then, the cylindrical rotary shaft 17 of the 1/3 rotary clutch 35
a, the shaft 14 and the cam 13 also rotate by 90 degrees to stop.

At this time, the cam 13 is in contact with the transfer roller swing plate 11 at an intermediate position 13c between the convex portion 13a and the concave portion 13b. Here, the transfer roller rocking plate 11 is
Is moved in the opposite direction to the intermediate transfer belt 7, and the transfer roller 10 is held at a distance of about 2 mm from the intermediate transfer belt 7. Further, since the protrusion 21 b of the cleaning roller rocking plate 21 maintains a gap with the leaf spring 41 of the transfer roller rocking plate 11, the cleaning roller 18 is urged against the transfer roller 10 by the spring 40. For this reason, the cleaning roller 18 is continuously driven by the transfer roller 10 and continuously performs cleaning of the transfer roller 10 for several seconds.

After the cleaning, the 1/3 rotation clutch 35 is energized for several tens of milliseconds, the slider 37 is sucked, and the locking portion 38c of the rotating plate 38 is released from the locking portion 37a of the slider 37. Then, the rotation shaft, the shaft 14 and the cam 13 are rotated 90 degrees by the drive gear. Then, when the power is turned off, the locking portion 37a of the slider 37 that has moved in the opposite direction and returned to the original position is engaged with the locking portion 38a of the rotating plate 38, and the rotation of the rotating plate 38 is stopped. And 1 /
The cylindrical rotary shaft 17a, the shaft 14, and the cam 13 of the three-rotation clutch 35 are also stopped by rotating 90 degrees.

Then, the convex portion 13a of the cam 13 comes into contact with the transfer roller rocking plate 11 to push down the transfer roller rocking plate 11 to the maximum. Thereby, the transfer roller 10 is separated from the intermediate transfer belt 7 by about 3 to 4 mm. Since the projection 21b of the cleaning roller rocking plate 21 is pushed down by the leaf spring 41 of the transfer roller rocking plate 11, the cleaning roller 18 is separated from the transfer roller 10 by 2 mm and waits for the next printing.

As described above, according to the present embodiment, the transfer roller 10 is cleaned without being affected by the intermediate transfer belt 7, so that the transfer roller 10 can be reliably cleaned. . As a result, there is little back stain on the paper, and in both-side printing, there is no toner stain on the front and back surfaces, and high quality printing can be performed.

The present invention can be applied to a four-pass machine that transfers four colors to a sheet for each color.

[0072]

As described above, according to the present invention, the transfer roller is cleaned without being affected by the intermediate transfer belt, so that the transfer roller can be reliably cleaned. Effects can be obtained.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram showing an image forming apparatus to which a transfer device according to an embodiment of the present invention is attached.

FIG. 2 is an explanatory diagram illustrating a transfer device in the image forming apparatus of FIG. 1;

FIG. 3 is an explanatory view showing a transfer device moved to a position different from that in FIG. 2;

FIG. 4 is an explanatory view showing the transfer device moved to a position different from those in FIGS. 2 and 3;

FIG. 5 is a perspective view showing a transfer device in the image forming apparatus of FIG. 1;

6 is a perspective view in which a transfer roller is omitted from FIG.

FIG. 7 is an explanatory diagram illustrating an operation of a transfer device in the image forming apparatus of FIG. 1;

FIG. 8 is an explanatory view showing a conventional transfer device.

FIG. 9 is a perspective view showing a main part of the transfer device of FIG. 8;

FIG. 10 is an enlarged plan view showing a part of the transfer device of FIG. 9;

FIG. 11 is a sectional view taken along the line BB of FIG. 10;

FIG. 12 is an explanatory view showing a conventional transfer device moved to a position different from FIG. 8;

[Explanation of symbols]

7 Intermediate Transfer Belt 8 Printing Paper 10 Transfer Roller 11 Transfer Roller Swinging Plate (Transfer Roller Holding Member) 13 Cam (Cam Member) 18 Cleaning Roller (Cleaning Member) 21 Cleaning Roller Swinging Plate (Cleaning Member Holding Member) 21b Projection ( Projection member) 36 Spring (biasing means) 40 Spring (biasing means)

Continued on the front page (72) Inventor Hiroaki Nakajima 1006 Kadoma, Kadoma, Osaka Prefecture Matsushita Electric Industrial Co., Ltd. F-term (reference) 2H032 AA05 BA09 BA18 BA19 BA23 BA30 2H071 BA03 BA05 BA14 BA29 DA09 DA13

Claims (4)

[Claims] A transfer roller which is pressed against an intermediate transfer belt on which a toner image is formed, and which nips and conveys a print sheet with the intermediate transfer belt to transfer the toner image onto the print sheet; and a surface of the transfer roller. , A cleaning member that cleans the surface of the transfer roller, a transfer roller holding member that holds the transfer roller detachably from the intermediate transfer belt, and a cleaning member that separates the transfer member from the transfer roller. A cleaning member holding member that is attached so as to be contactable and holds the cleaning member in contact with the transfer roller in conjunction with the separation operation of the transfer roller holding member, and then separates the cleaning member from the transfer roller And a transfer device comprising: A cam member for rotating the transfer roller holding member in contact with the transfer roller holding member to swing the transfer roller holding member to separate the transfer roller from the intermediate transfer belt; and a cleaning member for the transfer roller. A biasing unit for pressing and biasing the transfer roller against the intermediate transfer belt; and the cam member, wherein the transfer roller holding member transfers the transfer roller to the intermediate transfer belt. When the cleaning member is moved to a position where the transfer roller is brought into contact, the cleaning member is brought into contact with the transfer roller, and when the transfer roller holding member is moved to a position where the transfer roller is separated from the intermediate transfer belt, the cleaning member is brought into contact with the transfer roller. When the transfer roller holding member is further moved away from the intermediate transfer belt, the cleaning member is The transfer device of claim 1, wherein the copy roller and is swung in the opposite direction to separate said cleaning member from said transfer roller. 3. The cleaning member holding member has a projection member for separating the cleaning member from the transfer roller, between a swing fulcrum of the cleaning member holding member and a contact point between the transfer roller and the cleaning member. The transfer device according to claim 1, wherein the transfer device is disposed. 4. The transfer according to claim 1, wherein said transfer roller holding member is provided with an elastic body for rotating said cleaning member holding member with respect to a fulcrum of said cleaning member holding member. apparatus.