JP3192190B2 - Image forming device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image carrier for carrying a toner image, a transfer roller to which a bias voltage for transferring the toner image on the image carrier to a transfer material is applied, and the transfer roller. The present invention relates to an image forming apparatus comprising: a transfer roller contacting / separating unit for contacting / separating an image carrier with an image carrier; and a registration roller for feeding a transfer material between the image carrier and the transfer roller at a predetermined timing.

[0002]

2. Description of the Related Art In an image forming apparatus of the above-mentioned type constituted as an electronic copying machine, a facsimile or a laser printer, a toner image on an image carrier is transferred to a transfer material by a transfer roller to which a bias voltage is applied. This has the advantage that the amount of generated ozone can be suppressed as compared with the case where a corona discharger is used as the transfer device (see, for example, JP-A-2-285377).

Further, in this type of image forming apparatus, a transfer roller contacting / separating means for contacting / separating the transfer roller from / to the image carrier is provided. Can be kept away from the image carrier,
For this reason, it is possible to suppress a problem that the residual toner adhering to the image carrier is transferred to the transfer roller and adheres to the transfer material, thereby causing the transfer material to be stained on the back side.

Further, as in a color image forming apparatus, a predetermined color image is obtained by superposing toner images of different colors on an image carrier, and these are collectively transferred onto a transfer material such as plain paper. Even in an image forming apparatus of a type in which transfer is performed, the transfer roller can be kept away from the image carrier except when the toner image is transferred to a transfer material.
The problem that the untransferred toner image on the image carrier is disturbed by the transfer roller can be prevented.

The transfer material is fed between the transfer roller and the image carrier at a predetermined timing by the registration roller. At this time, the parallelism between the center axis of the registration roller and the center axis of the transfer roller is changed. Otherwise, the transferred transfer material may be wrinkled, and the transfer material may come into contact with the surface of the image carrier before the transfer of the toner image, thereby causing a problem that the transfer material is stained with toner.

In this type of conventional image forming apparatus,
Since the registration roller and the transfer roller had no special relationship and were separately supported, the parallelism of the center axes of the two was likely to be out of alignment due to the accumulation of these assembly tolerances, and the above-described problems were likely to occur. . In particular, when the transfer roller is supported so as to be able to freely contact and separate from the image carrier, it is more difficult to increase the parallelism between the transfer roller and the registration roller than when the transfer roller is fixedly supported.

[0007]

SUMMARY OF THE INVENTION The present invention has been made based on the above recognition, and an object of the present invention is to provide an image capable of increasing the parallelism between a registration roller and a transfer roller with a very simple structure. An object of the present invention is to provide a forming apparatus.

[0008]

[0009]

According to the present invention, in order to achieve the above object, in an image forming apparatus of the type described at the beginning, a transfer roller contacting / separating means includes a frame for rotatably supporting a transfer roller, and a frame for forming an image on the frame. A center shaft swingably supported with respect to the apparatus main body, a rotatable cam attached to the center shaft, and the registration roller contacting the cam directly or via an intermediate member; An image forming apparatus including a parallelism regulating unit that regulates the parallelism between a transfer roller and a registration roller is proposed.

[0011] In order to achieve the above object, the present invention provides
In the image forming apparatus of the type described at the beginning, the transfer roller contacting / separating means includes a frame that rotatably supports the transfer roller, and a center shaft that swingably supports the frame with respect to the image forming apparatus main body. A nut fixed to the image forming apparatus main body, a feed screw moving in the axial direction by rotating while being screw-engaged with the nut, and abutting the feed screw directly or via an intermediate member. Another aspect of the present invention is an image forming apparatus including a parallelism regulating unit that regulates the parallelism between the transfer roller and the registration roller by the central axis movable in response to the movement of the feed screw.

[0012]

Embodiments of the present invention will be described below in detail with reference to the drawings.

FIG. 1 is a partial view of a color image forming apparatus as an example of an image forming apparatus. Reference numeral 1 denotes a drum-shaped photosensitive member, which is driven to rotate in a direction indicated by an arrow. Sign 2
Denotes an intermediate transfer belt, which is wound around a driving roller 3, a bias roller 4, and a driven roller 5, and is driven at a constant speed with respect to the photosensitive member 1 in the direction of the arrow shown in the figure. Bias roller 4
Is in contact with the photoreceptor 1.

A first color toner image, for example, a yellow toner image is formed on the surface of the photoconductor 1 by a charging device, an exposure device, and a developing device (not shown). This toner image is transferred to the intermediate transfer belt 2 under the action of the bias voltage applied to the bias roller 4, and the residual toner adhered to the photoreceptor surface after the transfer of the toner image is removed by a cleaning device (not shown). Is removed from the photoreceptor surface.

Next, a magenta toner image, for example, is formed on the photoreceptor 1 in the same manner as described above, and this is superimposed on the yellow toner image already transferred on the intermediate transfer belt 2. Transcribed. A cyan toner image and a black toner image are sequentially formed on the photoreceptor 1 in the same manner, and these are sequentially transferred onto the intermediate transfer belt 2 so as to be superimposed on the toner image already transferred. Thus, a full-color toner image is formed on the intermediate transfer belt 2.

The intermediate transfer belt 2 carries the toner image as described above, and forms an example of the configuration of an image carrier.

The full-color toner image carried on the intermediate transfer belt 2 is applied to the transfer roller 7 on a transfer material 8 passing between the transfer roller 7 rotating in a counterclockwise direction and the intermediate transfer belt 2. The toner image is transferred under the action of a bias voltage for transferring the toner image. That is, the toner image on the intermediate transfer belt 2 is electrostatically transferred onto the transfer material 8 by the electric field formed by the bias voltage applied to the transfer roller 7. The transfer material 8 is made of, for example, plain paper. Hereinafter, such a transfer material will be referred to as a transfer paper.

The transfer paper 8 is fed at a predetermined timing between the transfer roller 7 and the intermediate transfer belt 2 which are in contact with each other, with the start of rotation of the pair of registration rollers 9 and 9a shown in FIG. The toner image is transferred to a predetermined area of the paper 8. The pair of registration rollers 9 and 9a are arranged in parallel with each other, and rotate while rolling and contacting each other.

The transfer paper 8 that has passed between the intermediate transfer roller 2 and the transfer roller 7 passes through a fixing device (not shown). At this time, the toner image on the transfer paper 8 is fixed on the transfer paper 8.

On the other hand, the toner remaining on the intermediate transfer belt after transferring the toner image is removed from the intermediate transfer belt 2 by the cleaning member including the cleaning brush roller 11 and the cleaning blade 12 of the cleaning device 10 shown in FIG. Removed.

Such cleaning members 11 and 12
If the toner image is kept in contact with the intermediate transfer belt 2 at all times, the toner image on the intermediate transfer belt 2 before being transferred onto the transfer paper 8 is broken.
0 is swingably supported around its pivot 13,
Until the transfer of the toner image onto the transfer paper 8 is completed, the cleaning device 10 is held at a position separated from the intermediate transfer belt 2 as shown in FIG. 1, and the cleaning members 11 and 12 are separated from the intermediate transfer belt 2. deep.

When the transfer of the toner image onto the transfer paper 8 is completed, the cleaning device 10 is rotated clockwise in FIG. 1 and its cleaning members 11 and 12 are brought into contact with the intermediate transfer belt 2 so that the belt 2 The upper residual toner is removed. After the completion of the cleaning operation, the cleaning members 11 and 12 are separated from the intermediate transfer belt 2.

For the same reason, the transfer roller 7 is separated from the intermediate transfer belt 2 except when the toner image is transferred from the intermediate transfer belt 2 to the transfer paper 8, and the toner on the belt 2 is disturbed. Has been blocked. For this purpose,
A transfer roller contacting / separating means for contacting / separating the transfer roller 7 from / to the intermediate transfer belt 2 is provided, and a specific configuration thereof is as follows.

As shown in FIGS. 2 and 3, a front plate 14 and a rear plate 14a constituting a support frame of the main body 6 are arranged in parallel with each other on the front side and the back side of the main body 6 of the image forming apparatus. ing.

On the other hand, the front and rear shaft portions of the transfer roller 7 are rotatably fitted to the long holes 16 and 16a formed vertically on the front and rear side plates of the frame 15 via bearing members. Compression coil springs 17, 1 attached to the long holes 16, 16a
It is urged upward by 7a.

A center shaft 18 is attached to the frame 15, and in the illustrated example, the center shaft 18 and the transfer roller 7 extend in parallel with each other. The rear end of the central shaft 18 is
The front end of the center shaft 18 is fitted into a support hole 21 formed in a small front side plate 20 which is detachably fixed to the front side plate 14 so as to fit into a reference hole 19 formed in the rear side plate 14a. Mated. The front small side plate 20 is also an element constituting a part of the image forming apparatus main body 6.

The frame 15 may be fixedly fixed to the center shaft 18 or may be rotatably supported. When fixed, the center shaft 18 is fixed to the rear plate 14a and the front small plate. It is rotatably supported on the side plate 20. In short, the frame 15 may be supported on the image forming apparatus main body 6 so as to be swingable around the central axis of the central shaft 18. Therefore, when the frame 15 is swingably supported by the center shaft 18, the center shaft 18 may be supported by the side plates 14a, 20 so as not to rotate, or may be supported rotatably.

On the other hand, each of the shaft ends of a cam 22 is rotatably supported by the front plate 14 and the rear plate 14a, and the cam surface of the cam 22 is in contact with the tip of the frame 15. This cam 2
2 is rotated by a driving device (not shown) to swing the frame body 15 around the central axis of the central shaft 18, thereby causing the transfer roller 7 to move the intermediate transfer belt 2.
Can be moved toward and away from. That is, when the full-color toner image on the intermediate transfer belt 2 is collectively transferred onto the transfer paper 8, the transfer roller 7 is brought into contact with the intermediate transfer belt 2, and a bias voltage is applied to the roller 7. When the toner image on the photoconductor 1 is being transferred to the transfer belt 2, the transfer roller 7 is separated from the intermediate transfer belt 2.

FIG. 4 shows a state in which the transfer roller 7 is separated from the intermediate transfer belt 2, and FIG.
, M, C in these figures indicate yellow toner, magenta toner, and cyan toner, respectively. Reference numeral 25 denotes a power supply for applying a bias voltage to the transfer roller 7.

As described above, the transfer roller contacting / separating means in this embodiment is a frame member 15 that rotatably supports the transfer roller 7.
A center shaft 18 for swingably supporting the frame 15 with respect to the image forming apparatus main body 6, and a cam 2 for swinging the frame 15
However, a driving device such as a solenoid can be used in place of the cam 22.

The transfer roller 7 and the frame 15 constitute a transfer unit for transferring the toner image on the intermediate transfer belt 2 to the transfer paper 8, and the frame 15 of the unit has, as shown in FIG. The base end of the cleaning blade 23 whose front end is pressed against the peripheral surface of the transfer roller 7 is fixed. The blade 23 is used to scrape foreign matter such as paper dust adhered to the transfer roller 7, and the scraped foreign matter falls into a collecting case 23 a detachably supported by the frame 15 and is stored therein. Is done.

By detaching the front small side plate 20 from the front side plate 14 as shown in FIG. 3, the transfer unit described above is pulled out together with the center shaft 18 to the front side of the image forming apparatus, and maintenance work on the unit is performed. You can do it. A notch 24 is formed in the front side plate 14 so that the transfer unit can be attached and detached.

By the way, as described above, the transfer paper 8 is transferred to the intermediate transfer belt 2 and the transfer roller 7 which are in contact with each other by the pair of registration rollers 9 and 9a arranged in parallel with each other.
At this time, it is desirable that the registration roller and the transfer roller 7 are arranged in parallel with high accuracy.

As shown in FIGS. 9 and 10, when the center axis of the transfer roller 7 is Ct and the center axis of the lower registration roller 9 is Cr, the parallelism between these two axes Ct and Cr is shifted. When the transfer of the toner image onto the transfer paper 8 is performed in this state, as shown in FIG. 10, the slack of the transfer paper 8 is deviated due to the shift of the transfer paper 8 in the traveling direction. Wrinkles may occur, or the transfer paper 8 may come into contact with the surface of the intermediate transfer belt before transfer, and the transfer paper 8 may be stained with toner. In a conventional image forming apparatus in which the transfer roller is supported so as to be able to freely move toward and away from the intermediate transfer belt, a small play of the transfer roller support portion and a slight play of the support member supporting the transfer roller accumulate. The parallelism between the transfer roller and the registration roller was easily shifted.

In view of this, the illustrated image forming apparatus is configured so that the parallelism between the two can be obtained with high accuracy by positioning the transfer roller 7 with reference to the registration roller 9. Reveal.

First, as shown in FIGS. 2 and 3, a positioning plate 26 formed in a cylindrical shape or a disc shape is fixedly provided concentrically with the central shaft 18 at a portion on the near side of the central shaft 18. I have. The positioning plate 26 may be rotatably supported on the center shaft 18.

On the other hand, the shaft portions of the upper and lower registration rollers 9 and 9a are rotatably supported by the front side plate 14 and the rear side plate 14a, respectively, and the positions thereof are correctly set in advance.

At this time, the hole 27 of the rear plate 14a that supports the shaft portion on the back side of the lower registration roller 9 and the reference hole 19 of the rear plate 14a that supports the back end of the center shaft 18 described above.
The distance between the centers of the registration rollers 9 is L, as shown in FIG.
Assuming that the radius of No. 8 is Da and Db as shown in FIG. 2, each size is set so as to satisfy L = Da + Db. The reference hole 19 and the hole 27 for supporting the shaft portion on the back side of the registration roller 9 are formed in the same rear plate 14a, and their positions are set with high precision.

As shown in FIG. 3, the front small side plate 20 is provided with a support hole 21 for supporting the front end of the center shaft 18 as described above. A hole 29 into which the shaft portion 28 on the front side fits substantially without backlash, and a long hole 30 are formed.
9 and 30 are located on the same plane, in this example, a horizontal plane, and the long hole 30 is formed long along this plane.

Further, a screw hole 32 is formed in the front side plate 14, and the screw hole 32 is formed in the above-described horizontal plane with reference to the hole 31 of the front side plate 14 that supports the shaft 28 on the front side of the registration roller 9. Are located in A screw 33 is screwed into the long hole 30 formed in the front small side plate 20 and the screw hole 32 and tightened, and another screw hole 34 formed in the front small plate 14 and the front small small plate 20 are formed. Another screw 36 is screwed into the formed hole 35 and the front small side plate 20 is fixed to the front side plate 14 by tightening the screw.

The support hole 21 formed in the front small side plate 20 in which the central shaft 18 is fitted is also formed to be long in the horizontal plane direction. In this support hole 21, a pressing member comprising a compression coil spring 37 is disposed. Have been.

To attach the front small side plate 20 to the front side plate 14, before screwing the screws 33 and 36, the holes 29 of the front small side plate 20 are fitted to the shaft 28 of the registration roller 9, and The front end of the register roller 18 is fitted into the support hole 21, and the small front plate 20 is fixed to the front plate 14 with screws 33 and 36. At this time, the shaft of the registration roller 9 previously occupied a predetermined position. Since the holes 28 are fitted in the holes 29, the front small side plate 20 is correctly positioned and attached to the front side plate 14.

When the front small side plate 20 is fixed to the front side plate 14 in this manner, the end of the center shaft 18 on the near side is provided with the support hole 21.
Is pressed toward the registration roller 9 in the above-mentioned horizontal plane by the compression coil spring 37 attached to the shaft 2 of the registration roller 9.
8 is pressed. At this time, the shaft 28 of the registration roller 9
The radius Db of the positioning plate 26 and the radius Da of the positioning plate 26 have the relationship of L = Da + Db, as described above. Therefore, the center-to-center distance between the registration roller 9 and the center shaft 18 is L at the near side. It becomes the size of. Back side registration roller 9
The center-to-center distance between the axis and the center axis 18 is also set to L in advance, so that both are positioned parallel to each other.

On the other hand, since the center shaft 18 and the transfer roller 7 are also arranged in parallel in advance,
The center axes of the transfer roller 7 and the transfer roller 7 are arranged in parallel with high accuracy. In this way, the transfer roller 7 can be positioned with the registration roller 9 as a reference, and both can be arranged in parallel with each other. Therefore, it is possible to prevent the transfer paper 8 from being wrinkled or the transfer paper 8 from being stained with toner as shown in FIG.

In the above embodiment, the intermediate member made up of the positioning plate 26 is fixed to the central shaft 18, and the central shaft 18 and the registration roller 9 are brought into contact with each other through the intermediate member. Alternatively, another intermediate member, for example, a bearing may be mounted on the shaft portion 28 of the registration roller 9, and the center shaft 18 may be directly connected thereto or an intermediate member such as the positioning plate 26 may be attached thereto. Alternatively, the contact may be made.

As described above, in the present embodiment, the parallelism regulating mechanism for regulating the parallelism between the transfer roller 7 and the registration roller 9 by the center shaft 18 and the registration roller 9 which comes into contact with the center shaft 18 directly or via an intermediate member. Means are configured.

In the second embodiment shown in FIG.
Is not provided, and instead, the front side portion 38 of the frame 15 is brought into contact with the shaft portion 28 (both shown in FIG. 2) of the registration roller 9 to transfer it to the registration roller 9. It is configured to obtain the parallelism with the roller 7. That is, the peripheral edge of the front side portion 38 of the frame 15 has a radius R = D with respect to the center of the hole of the frame 15 in which the central shaft 18 is fitted.
a, and the peripheral edge of which is
Is brought into contact with the shaft portion 28 of the second member. Also in the second embodiment, the radius of the shaft 28 of the registration roller 9 is Db.
(FIG. 2), the distance between the center axis of the center axis 18 and the center axis of the registration roller 9 is set to L = Da + Db on both the front side and the back side, so that the transfer roller 7 and the registration roller 9 are parallel to each other. Positioned. Other configurations are the first
There is no difference from the embodiment. Also in this case, the portion 38 of the frame 15 can be brought into contact with the registration roller 9 via an intermediate member (not shown).

In the second embodiment, the parallelism regulating means for regulating the parallelism between the transfer roller 7 and the registration roller 9 by the frame 15 and the registration roller 9 which comes into contact with the frame body 15 directly or via an intermediate member. According to such a configuration, the positioning plate 26 in the first embodiment can be omitted, and the number of components can be reduced.

FIG. 7 is a front view showing a third embodiment.
In this embodiment, the hole 29a of the front small side plate 20 into which the shaft portion 28 of the registration roller 9 is fitted is, for example, an elongated hole formed in a horizontal plane, and is rotatable in the front side plate 14 without being moved. The front small side plate 20 is movable in the horizontal direction with respect to the shaft portion 28 supported by the front side. This long hole 29a
Is mounted with a compression coil spring 40 which is an example of a pressing member for urging the front small side plate 20 rightward in FIG. Further, a positioning plate fixed to a portion on the front side of the center shaft 18 is formed as a disc-shaped eccentric cam 26a, and the front small side plate 20 to which the end of the center shaft 18 fits.
The hole 21a is not a long hole, and the end portion is a hole 21a that is rotatably fitted without substantially rattling. The cam 26a and the shaft 28 of the registration roller 9 can be pressed against each other by the spring 40 described above. The compression coil spring 37 and the positioning plate 26 shown in FIG. 2 are not provided, and other configurations are the same as those of the first embodiment.

In the third embodiment, screws 33,
Before the front small side plate 20 is fixed to the front side plate 14 by 36, for example, the tip of a driver (not shown) is engaged with a groove 39 formed on the front end surface of the central shaft 18 to thereby form the central shaft 1
Rotate 8. Accordingly, the cam 26a also rotates, and the front small side plate 20 also moves left and right. On the other hand, since the registration roller 9 against which the cam 26a is pressed by the action of the spring 40 does not move, the distance L1 between the center axis of the roller 9 and the center axis of the center shaft 18 changes, thereby changing the registration. By finely adjusting the parallelism between the central axes of the roller 9 and the transfer roller 7, both can be positioned parallel to each other. After the adjustment work is completed, the screws 33 and 36 are tightened to fix the small front side plate 20 to the front side plate 14. Center axis 1
8 and the cam 26a are also desirably fixed to the front small side plate 20. For example, a screw is formed at the front end of the central shaft 18, and a nut (not shown) is screwed into the screw and tightened. The central shaft 18 can be fixed to the small side plate 20. In this case, the frame 15 is swingably supported with respect to the center shaft 18.

Of course, also in this embodiment, the cam 26a
May be brought into contact with the registration roller 9 via an intermediate member (not shown).

The cam 26a is rotatably supported on the center shaft 18, and the cam 26a is rotatable in exactly the same manner as described above.
a, the position of the center shaft 18 with respect to the registration roller 9 pressed against the roller a may be adjusted, and the parallelism between the registration roller 9 and the transfer roller 7 may be adjusted.

As described above, in the third embodiment, the transfer roller is formed by the rotatable cam 26a attached to the center shaft 18 and the registration roller 9 which comes into contact with the cam 26a directly or via an intermediate member. Parallelism restricting means for restricting the parallelism between the registration roller 7 and the registration roller 9 is configured.

FIG. 8 is a front view showing the fourth embodiment.
In this example, the positioning plate 26 shown in FIG.
0 is not provided. Instead, the front end of the center shaft 18 that supports the frame 15 is fitted into the elongated support hole 21b formed in the front plate 14, and It is movable. The fact that the registration roller 9 is supported by the front side plate 14 so as to be stationary and rotatable is the same as in the first embodiment.

A pressure member made of a compression coil spring 37a is mounted in the support hole 21b, and the center shaft 18 is urged away from the registration roller 9.

A nut 41 is fixedly disposed on the front side plate 14 which constitutes a part of the image forming apparatus main body 6.
A feed screw 42 is engaged with 1, and one end of the feed screw 42 is pressed against the end of the central shaft 18 directly or via an intermediate member (not shown). A knob 43 is formed at the other end of the feed screw 42. Other configurations are the same as those of the first embodiment shown in FIGS.

To adjust the parallelism between the transfer roller 7 and the registration roller 9, the knob 43 is turned, and the feed screw 42 screwed to the nut 41 is rotated, and is moved in the axial direction. Thereby, the end on the near side of the center shaft 18 moves in the direction to approach or separate from the registration roller 9 together with the front side of the frame 15, thereby positioning the transfer roller 7 and the registration roller 9 in parallel. be able to.

In the fourth embodiment shown in FIG. 8, the parallelism restricting means for restricting the parallelism between the transfer roller and the registration roller includes a nut 4 fixed to the main body 6 of the image forming apparatus.
1, a feed screw 42 which moves in the axial direction by rotating while being screw-engaged with the nut 41, and abuts the feed screw 42 directly or via an intermediate member, and
And the center shaft 18 that is movable in response to the movement described above. However, the configuration of this embodiment can also be applied to an image forming apparatus having a front small side plate.

The image forming apparatus shown in FIG. 1 is configured such that the toner image formed on the photoreceptor 1 is temporarily transferred to the intermediate transfer belt 2, and then this toner image is transferred to the transfer paper 8. However, for example, the present invention can also be applied to an image forming apparatus of a type in which a toner image formed on a latent image carrier from a photoconductor is directly transferred to a transfer material, and in this case, the latent image carrier is An image carrier that carries the toner image is configured. The present invention is also applicable to non-color type image forming apparatuses.

[0060]

In the image forming apparatus according to the first aspect, the center axis of the frame that rotatably supports the transfer roller is positioned with respect to the registration roller. The parallelism of the central axis can be obtained with high accuracy.

In the image forming apparatus according to the second aspect, the accuracy of the parallelism between the transfer roller and the registration roller can be improved by sufficiently absorbing the error due to the assembly tolerance and rotating the feed screw.

[0062]

[Brief description of the drawings]

FIG. 1 is a schematic diagram illustrating a part of a color image forming apparatus.

FIG. 2 is a front view showing details of a transfer roller and a configuration related thereto.

FIG. 3 is a perspective view of FIG. 2 with some elements omitted;

FIG. 4 is an explanatory diagram showing a state in which a transfer roller is separated from an intermediate transfer belt.

FIG. 5 is an explanatory diagram illustrating a state in which a transfer roller is in contact with an intermediate transfer belt.

FIG. 6 is a partial front view showing a second embodiment.

FIG. 7 is a front view showing a third embodiment.

FIG. 8 is a front view showing a fourth embodiment.

FIG. 9 is a plan view illustrating a parallel state of a registration roller and a transfer roller.

FIG. 10 is a perspective view illustrating a problem when the parallelism between the registration roller and the transfer roller is deteriorated.

[Explanation of symbols]

 7 Transfer Roller 8 Transfer Material 9 Registration Roller 9a Registration Roller 15 Frame 18 Center Shaft 26a Cam 41 Nut 42 Feed Screw

Claims (2)

(57) [Claims] An image carrier for carrying a toner image; a transfer roller to which a bias voltage for transferring the toner image on the image carrier to a transfer material is applied; An image forming apparatus comprising: a transfer roller contacting / separating unit for bringing the transfer material into and out of contact with each other; and a registration roller for feeding a transfer material between the image carrier and the transfer roller at a predetermined timing. A rotatable cam, a center axis for swingably supporting the frame body with respect to the image forming apparatus main body, and a rotatable cam attached to the center axis. An image forming apparatus, comprising: a parallelism regulating unit configured to regulate a parallelism between the transfer roller and the registration roller by the registration roller that contacts directly or via an intermediate member. 2. An image carrier for carrying a toner image, a transfer roller to which a bias voltage for transferring the toner image on the image carrier to a transfer material is applied, and the transfer roller is moved relative to the image carrier. An image forming apparatus comprising: a transfer roller contacting / separating unit for bringing the transfer material into and out of contact with each other; and a registration roller for feeding a transfer material between the image carrier and the transfer roller at a predetermined timing. A frame rotatably supporting the frame, a center shaft rotatably supporting the frame with respect to the image forming apparatus main body, and a nut fixed to the image forming apparatus main body; The transfer roller is formed by a feed screw that moves in the axial direction by rotating while being combined with the feed screw, and the center shaft that abuts the feed screw directly or via an intermediate member and is movable in accordance with the movement of the feed screw. And resist An image forming apparatus characterized by being configured parallelism regulating means for regulating the parallelism between over la.