JP2000137412A - Process cartridge and image forming device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent the shake of a backup member and to form an excellent image without causing the positional deviation of a belt type image carrier by molding a resin easing by integrating a belt body state support on which the backup member is provided and an opposed rib member having symmetric shape with the backup member. SOLUTION: The resin casing 140 is constituted by providing the belt body state support 40 and a supporting shaft functioning as a bearing member rotatably pivotally supporting a roller member on a rear side plate 40B integrally with the plate 40B. The easing 140 is formed of a resin member. Plural sets of plate-like backup members 41 and 42 and an auxiliary backup member are integrally provided along a belt body on the support 40 of the easing 140. The members 41 and 42 are provided on the support 40 provided in the casing 140, and the plate-like opposed rib members 141 and 142 having the symmetric shape with the members 41 and 42 are provided integrally on the support 110 of the casing 140 symmetrically with respect to the support 40.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention forms an image on a belt-shaped image carrier by arranging a charging means, a scanning means and a developing means around a belt-shaped image carrier such as a copying machine, a printer, a facsimile or the like. The present invention relates to an electrophotographic image forming apparatus and a process cartridge used in the image forming apparatus.

[0002]

2. Description of the Related Art Conventionally, in an electrophotographic image forming apparatus, a charging means, a scanning means and a developing means are arranged around a photosensitive drum (image carrier) or a belt photosensitive body (belt-shaped image carrier). Then, a toner image is formed on a photoreceptor drum or a belt photoreceptor, transferred to a recording paper (transfer material) and fixed. The belt photoreceptor is designed to be compact because its shape can be freely selected, and the belt photoreceptor is stretched between a plurality of rollers (roller members) for the purpose of ensuring separation of the recording paper after transfer. For example, Japanese Patent Application Laid-Open No. 8-339110 discloses an image forming apparatus that forms an image by bridging a belt, and a belt photoconductor unit (process cartridge) in which a belt photoconductor is stretched between a plurality of rollers (roller members) for the same purpose. Proposed in gazettes.

[0003]

However, in the process cartridge and the image forming apparatus proposed above, the belt-shaped image carrier is stretched by a plurality of roller members.
Since the tension roller is configured to apply tension to the belt-shaped image carrier, the developing position and the scanning unit, which are opposed to the developing unit provided opposite to the belt-shaped image carrier, are stretched by only a plurality of roller members. There is a problem that a tensioned tension of the belt-shaped image carrier at the opposing scanning position cannot be obtained, and good image formation cannot be performed. Therefore, in an image forming apparatus using a belt-shaped image carrier, the backup member is brought into contact with the backup member from the back side at the scanning position and the developing position on the belt-shaped image carrier, and the belt-shaped image carrier and the scanning unit, the belt-shaped image carrier The positions of the body and the developing means are set accurately. However, if the backup member and the roller that stretches the belt-shaped image carrier are adjacent to each other, when the belt-shaped image carrier rotates, the run-out of the roller affects the backup member and is stretched over the backup member. The position of the belt-shaped image carrier and the scanning unit and the position of the belt-shaped image carrier and the developing unit deviate from each other, resulting in a problem that good images cannot be formed.

Considering the reason for forming the backup member, it is necessary to use a non-magnetic material for the backup member when the backup portion is located opposite to the development. Therefore, it is necessary to use a non-magnetic metal if it is to be formed from a metal, and there is a problem in terms of cost in consideration of processing magnetization. Therefore, in consideration of cost and productivity, it is considered that the backup member is formed of resin, and the backup member, the belt-shaped image carrier, and the support shaft for supporting the roller member are integrally formed into a resin casing. . However, since resin casings are generally large, it is difficult to mold a resin casing having a required back-up member with a straightness of the order of microns and warpage occurs in the backup member during molding. The problem arises.

The present invention solves the above-mentioned problems, provides a process cartridge in which a backup member without a warp is formed, and a developing position and a scanning position are accurately set, and a belt-shaped image carrier is stretched. Provided is a process cartridge and an image forming apparatus that prevent a backup member from oscillating due to a roller member from oscillating and cause a good image formation without causing a displacement of a belt-shaped image carrier at a developing position or a scanning position. The purpose is to do.

[0006]

An object of the present invention is to provide a process cartridge having a belt-shaped image carrier, a plurality of roller members for stretching the belt-shaped image carrier, and a resin casing for supporting the roller members. A backup member abutting on the belt-shaped image carrier from the back side of the belt-shaped image carrier; a band-shaped support provided with the backup member; and a backup member arranged symmetrically with respect to the support. The first aspect of the present invention is achieved by a process cartridge in which the backup casing and the symmetrically opposed rib member are integrally formed with the resin casing.

Another object of the present invention is to provide a belt-shaped image carrier,
A plurality of roller members for stretching the belt-shaped image carrier,
In an image forming apparatus having a resin casing that supports the roller member, a backup member that contacts the belt-shaped image carrier from the back side of the belt-shaped image carrier, and a band-shaped support provided with the backup member And the resin casing is molded integrally with the backup member and a symmetrically opposed rib member disposed symmetrically with the backup member with respect to the support. (Second invention).

[0008] Further, the object is to provide a belt-shaped image carrier,
Scanning position of a scanning unit for forming a latent image by scanning a scanning light provided opposite to the belt-shaped image carrier or development of a developing unit provided opposite to the belt-shaped image carrier for developing the latent image A process cartridge having a plurality of backup members abutting on the belt-shaped image carrier from the back side of the belt-shaped image carrier at a position, and a plurality of roller members spanning the belt-shaped image carrier. ,
A process cartridge, comprising: an auxiliary backup member that contacts the belt-shaped image carrier from the back side of the belt-shaped image carrier between the backup member and the roller member adjacent to the backup member. (Third invention).

Further, the above object is to provide a belt-shaped image carrier,
Scanning means for scanning the belt-shaped image carrier with a scanning light to form a latent image, developing means for developing the latent image formed on the belt-shaped image carrier, and A plurality of backup members that contact the belt-shaped image carrier from the back side of the belt-shaped image carrier at a scanning position by the scanning unit or a development position by the developing unit on the belt-shaped image carrier; An image forming apparatus having a plurality of roller members for stretching a belt-shaped image carrier, wherein the back side of the belt-shaped image carrier is between the backup member and the roller member adjacent to the backup member. The fourth aspect of the present invention is achieved by an image forming apparatus characterized in that an auxiliary backup member is provided for contacting the belt-shaped image carrier.

[0010]

Embodiments of the present invention will be described below. Note that the description in this column does not limit the technical scope of the claims and the meaning of terms. Also, the following assertive description in the embodiment of the present invention indicates the best mode, and does not limit the meaning of the terms of the present invention or the technical scope.

The structure of a process cartridge according to the present invention and the image forming process and each mechanism of an embodiment of an image forming apparatus having the process cartridge will be described with reference to FIGS. FIG. 1 is a sectional view of a color image forming apparatus showing an embodiment of an image forming apparatus having a process cartridge according to the present invention, and FIG. 2 is a detachable view of the process cartridge from the image forming apparatus. 3 is a configuration diagram of a process cartridge, FIG. 4 is a partially enlarged perspective view of a resin casing, and FIG. 5 is an explanatory diagram showing a state in which a developing unit and a scanning unit face a belt-shaped image carrier. 6 is a partially enlarged view showing an angle formed between the backup member and the auxiliary backup member of FIG. 5 with respect to the belt-shaped image carrier.

According to FIG. 1 or 2, a belt photoreceptor 10, which is a belt-shaped image carrier, is stretched around a driving roller 1, a first rotating roller 2, and a second rotating roller 3 as roller members. The endless flexible photoreceptor belt is tensioned by the action of the tension roller 4 so as to locally contact the backup members 41 and 42 and the auxiliary backup member 43 provided on the inner peripheral surface. 1 rotates clockwise as indicated by the arrow.

The belt photoreceptor 10 is provided with a thin metal film such as tin oxide, lead oxide or indium oxide as a conductive layer on a flexible substrate such as polyester, polyimide or polyethylene terephthalate. ) Is applied, and the conductive layer is grounded. The belt photoreceptor 10 used in the present embodiment has a base of 80 μm thick polyethylene terephthalate and is coated with OPC.
It is molded with high precision so as to have a uniform thickness of μm.

The belt photoreceptor 10 is provided with a cleaning device 19 as a belt-shaped image carrier cleaning means described later.
And the waste toner collecting container 190 and the resin casing 140
And is configured as a process cartridge 300.

A scorotron charger 11 as a charging unit, an exposure optical system 12 as a scanning unit, and a developing unit 13 as a developing unit, which will be described below, are respectively yellow (Y), magenta (M), and cyan (C). And black (K)
Are used for the image forming process of each color, and in the present embodiment, the belt photoconductor 1
0, Y, M, C, and K are arranged in this order with respect to the rotation direction of the belt photoconductor 10 indicated by the arrow in FIG.

A scorotron charger 11 as a charging means for each color is opposed to and close to the belt photoreceptor 10 in a direction orthogonal to the moving direction of the belt photoreceptor 10 as an image forming body (perpendicular direction in FIG. 1). A control grid (without a sign) maintained at a predetermined potential with respect to the aforementioned organic photosensitive layer of the belt photoreceptor 10 and a corona discharge electrode (without a sign), for example, a saw-tooth electrode, The charging action (minus charging in the present embodiment) is performed by corona discharge having the same polarity, and the belt photoconductor 10 is charged.
To give a uniform potential. As a corona discharge electrode,
In addition, a wire electrode or a needle electrode can be used.

An exposure optical system 12 serving as a scanning unit for each color.
Scans (exposes) a laser beam emitted by a semiconductor laser with a polygon mirror rotated by a drive motor, scans (exposes) scanning light (exposure light) on the belt photoreceptor 10 via an fθ lens, and forms a latent image. Perform formation. This scanning light is performed by subjecting image signals of respective colors read by a separate image reading device to image processing and inputting them to the exposure optical system 12 as electric signals.

The exposure optical system 12 for each color scans the belt photoconductor 10 between the scorotron charger 11 and the developing unit 13 by scanning the belt photoconductor 10 with scanning light. It is arranged outside the photoconductor 10 away from the photoconductor 10.

The developing device 13 as a developing means for each color includes
Inside yellow (Y), magenta (M), cyan (C)
Alternatively, a two-component (or one-component) developer of black (K) is accommodated, and the belt surface is arranged on one side of the vertically arranged belt photoconductor 10 at right angles to the moving direction of the belt photoconductor 10. The developer is a cylindrical developer carrier formed of a non-magnetic stainless steel or aluminum material having a thickness of, for example, 0.5 mm to 1 mm and an outer diameter of 15 to 25 mm, respectively. A sleeve 131 is provided.

In the developing area, the developing sleeve 131 is kept out of contact with the belt photoreceptor 10 by a contact roller (not shown) with a predetermined gap, for example, 100 μm to 1000 μm, to rotate the belt photoreceptor 10. And a DC voltage of the same polarity as the toner (in this embodiment, a negative polarity) or a voltage that superimposes the AC voltage AC on the DC voltage is applied to the developing sleeve 131 as a developing bias. As a result, non-contact reversal development is performed on the exposed portion of the belt photoconductor 10. At this time, the precision of the development interval needs to be about 20 μm or less in order to prevent image unevenness.

To the developing device 13 for each of the colors Y, M, C and K, a developer for supplying each of the colors Y, M, C and K supplies toner corresponding to Y, M, C and K. It is supplied from the tank 24.

As described above, the developing device 13 transfers the electrostatic latent image formed on the belt photoreceptor 10 formed by the charging by the scorotron charger 11 and the scanning light by the exposure optical system 12 to the belt photoreceptor in a non-contact state. The reversal development is performed with toner having the same polarity as the charge polarity of No. 10 (in this embodiment, the belt photoconductor is negatively charged, and the toner has negative polarity).

At the start of image recording, the drive motor rotates and the belt photoreceptor 10 rotates clockwise via the drive roller 1, and the Y-scorotron charger 11 charges the belt photoreceptor 10 to the belt photoreceptor 10. The application of the potential is started. After a potential is applied to the belt photoreceptor 10, scanning exposure is started in the Y exposure optical system 12 by an electric signal corresponding to a first color signal, that is, an image signal of yellow (Y), and rotation of the belt (sub-scanning) is performed. ), An electrostatic latent image corresponding to the yellow (Y) image of the developed image is formed on the photosensitive layer on the surface. This latent image is reversely developed in a state where the yellow (Y) developer adhered and conveyed onto the developing sleeve 131 by the Y developing device 13 in a non-contact state, and the belt photoreceptor 1
Yellow (Y) on the belt photoreceptor 10 according to the rotation of 0
Is formed.

Next, the belt photoreceptor 10 places an M scorotron charger 11 on the yellow (Y) toner image.
A potential is applied by the charging action of the M exposure optical system 12
The second color signal, that is, the scanning exposure by the electric signal corresponding to the image data of magenta (M) is performed, and the non-contact reversal development by the M developing unit 13 causes the yellow (Y) toner image to A magenta (M) toner image is formed to overlap.

According to the same process, the cyan (C) toner image corresponding to the third color signal is further obtained by the C scorotron charger 11, the exposure optical system 12, and the developing device 13, and the K scorotron charger 11 is also provided. , Exposure optical system 1
A black (K) toner image corresponding to the fourth color signal is sequentially superimposed and formed by the second and developing units 13, and a color toner image is formed on the peripheral surface within one rotation of the belt photoconductor 10. You.

The color toner image formed on the peripheral surface of the belt photoreceptor 10 is subjected to charge removal by the pre-transfer exposure unit 16a after the potential of the attached toner is adjusted by the uniform charger 11A.

On the other hand, the recording paper P as the transfer material is sent out from one of the paper feed cassettes 15A and 15B as the transfer material storage means by the corresponding feed rollers 15a and 15b, and is conveyed to the timing roller 15c.

The recording paper P is fed to the transfer area in synchronization with the color toner image carried on the belt photoreceptor 10 by the driving of the timing roller 15c, and is driven in the transfer area. A transfer roller 16b as a transfer unit to which a voltage having a polarity opposite to that of the toner (positive polarity in the present embodiment) is applied opposite to the lower portion of the driving roller 1 for transfer, and the peripheral surface of the belt photoreceptor 10 Are collectively transferred to the recording paper P.

The recording paper P to which the toner image has been transferred is separated from the peripheral surface of the belt photoreceptor 10 along the curvature of the driving roller 1 and then conveyed to a fixing device 17 where a heater (not shown) is provided. ) And the pressure roller 1
7b, the toner adhered to the recording paper P is fixed by applying heat and pressure to the recording paper P.
The toner image surface on the recording sheet P is conveyed by the paper discharge roller 18b and sent by the paper discharge roller 18 to a paper discharge tray 20 provided on the upper portion of the image forming apparatus 100 and also serving as an opening / closing lid for taking out the process cartridge 300. Is discharged with the bottom facing.

The toner remaining on the peripheral surface of the belt photoreceptor 10 after the transfer is removed from the surface of the belt photoreceptor 10 by a cleaning blade 19a which is a cleaning member provided in a cleaning device 19 as a belt-shaped image carrier cleaning means. The rubbing is performed, the residual toner is removed and cleaned, and the formation of the toner image of the next original image is continued, or
Alternatively, stop temporarily and wait. The waste toner removed from the belt photoreceptor 10 by the cleaning blade 19a is collected from the cleaning device 19 to a waste toner collection container 190 through, for example, a conveying screw (not shown). When the formation of the toner image of the next original image is subsequently performed, the belt photoreceptor 1
Exposure is performed on the surface of the photosensitive member 0 to remove the previous history.

Further, as shown in FIG.
The process cartridge 300 having an opening 0 opens and closes the above-described paper discharge tray 20 at the upper part of the image forming apparatus 100, and uses the holes 40a and 40b provided in the front side plate 40A and the rear side plate 40B constituting the process cartridge 300 as a handle. It is detachable, and maintenance and replacement of the belt photoreceptor 10, the cleaning device 19, the waste toner collecting container 190, etc., and replacement of the process cartridge 300 are performed. At this time, the developing device 1 for each color described with reference to FIG.
3 is a lever (not shown) associated with the opening of the paper discharge tray 20, for example.
The belt is retracted from the surface of the photoconductor 10 by the operation of the cam or the like. When the sheet discharge tray 20 is closed, an abutment roller (not shown) is brought into contact with the surface of the belt photoreceptor 10 by the operation of the lever, the cam, and the like, and the developing device 13 is positioned.

According to FIG. 3 or FIG. 4, a band-shaped column 40 and a support shaft 1a as a bearing member for rotatingly supporting the roller member are integrally formed on the rear side plate 40B with the rear side plate 40B.
The resin casing 140 is formed by providing 2a and 3a. A resin casing 140 is formed by the resin member. A plurality of flat backup members 41 and 42 and an auxiliary backup member 43 are integrally provided on the support 40 of the resin casing 140 along the band. The backup member 41 is a developing device 1 for each color of Y, M, C and K.
3 and a backup member 42 is provided with a Y, M, C, and K exposure optical system 1.
2 is provided at a position (scanning position) opposite to the scanning unit where exposure scanning is performed on the photosensitive layer of the belt photosensitive member 10 (see FIG. 5). The driving roller 1, the first rotating roller 2, and the second rotating roller 3 are fitted on the support shafts 1a, 2a, 3a, respectively. An endless belt photoreceptor 10 is stretched around a driving roller 1, a first rotating roller 2, and a second rotating roller 3 including a support column 40 on which backup members 41 and 42 and an auxiliary backup member 43 are provided. The belt photoreceptor 10 is tensioned by the tension roller 4 pressed by a spring or the like (not shown). As a result, the inner peripheral surface of the belt photoconductor 10 abuts on the backup members 41 and 42 and the auxiliary backup member 43 locally. With the cleaning device 19 and the waste toner collecting container 190 attached to the resin casing 140, the support shafts 1a, 2a, 3a, the backup members 41, 42, and the auxiliary backup member 43
The front plate 40A (not shown in FIG. 3) shown in FIG. 2 is attached to the resin casing 140 symmetrically with the rear plate 40B with the support 40 provided therebetween, thereby forming the process cartridge 300.

As shown in FIG. 3, the column 40 provided on the resin casing 140 molded by a resin member has
For the flat backup members 41 and 42,
Symmetrically to the backup members 41, 42, plate-shaped opposed rib members 141, 142 having a symmetrical shape are provided integrally with the support 40 of the resin casing 140. Further, between the backup member 42 provided at the scanning position of the same color and the backup member 41 provided at the developing position, and between the backup member 41 provided at the developing position and the backup member 42 provided at the scanning position of the next color. The flat auxiliary ribs 44 are provided between the support columns 40 of the resin casing 140.
The auxiliary ribs 44 are provided integrally with the auxiliary ribs 44, and the plate-like opposing auxiliary ribs 144 having a symmetrical shape with respect to the support ribs 44 are symmetrically formed with respect to the support columns 40.
Are provided integrally with the supporting column 40. The tip of the auxiliary rib 44 is provided to be separated from the back surface of the belt photoconductor 10.

Although the auxiliary ribs 44 and the opposing auxiliary ribs 144 are not always necessary, the scorotron charger 1 described above is used.
1 and the developing unit 13 are arranged on the outer peripheral surface of the belt photoreceptor 10, so that a gap is required between the backup member 42 provided at the scanning position of the same color and the backup member 41 provided at the developing position, or Preferably, at least one or more members are provided between the backup member 41 provided at the developing position and the backup member 42 provided at the next color scanning position.

The column 40 has opposed rib members 141, 1 symmetrical to the respective backup members 41, 42.
42, a plurality of auxiliary ribs 44, and respective auxiliary ribs 4
A mold (not shown) in which the resin casing 140 integrally provided with the opposing auxiliary ribs 144 and the like symmetrical with respect to the mold 4 is divided into two parts in the direction of the arrow, with the parting line indicated by the one-dot chain line in FIG. Molded by

As described above, there is provided a process cartridge and an image forming apparatus in which a backup member having a straightness of a micron order and having no warp is formed, and a developing position and a scanning position are accurately set.

According to FIG. 5 or FIG. 6, the backup member 41 is located at the developing means facing position (developing position) facing the developing sleeve 131 of the developing device 13 for each of the colors Y, M, C and K. 42 is Y, M, C and K
Are provided at scanning device opposing positions (scanning positions) where exposure scanning is performed on the photosensitive layer of the belt photoreceptor 10 by the exposure optical system 12. The backup member 41 provided inside the belt photoreceptor 10 includes: A semi-cylindrical tip portion 41a having a tip radius of 1.5 mm is provided at a developing device facing position (developing position) facing the developing sleeve 131 of the developing device 13 for each of the colors Y, M, C, and K, Belt photoreceptor 10
Are provided in such a manner that they come into contact with each other in a direction orthogonal to the rotation direction of the belt photoconductor 10. Also, Y,
The belt photoreceptor 10 is exposed by the M, C, and K exposure optical systems 12.
On the back side of the scanning means facing position (scanning position) where the exposure scanning is performed on the photosensitive layer, the same as the backup member 41 described above for the purpose of preventing vibration or fluctuation occurring during rotation of the belt photoreceptor 10 surface. A small cylindrical semi-cylindrical tip 42 a having a tip radius of 1.5 mm is provided on the backup member 42 so as to abut each other in a direction orthogonal to the rotation direction of the belt photoreceptor 10. The auxiliary backup member 43 provided inside the belt photoreceptor 10 is also provided with a semi-cylindrical tip 43a having a tip radius of 1.5 mm,
A front end portion 43a is provided on the back surface of the belt photoconductor 10 so as to abut in a direction orthogonal to the rotation direction of the belt photoconductor 10. The belt photoreceptor 10 stretched between the first and second rotation rollers 2 and 3 is given a constant tension to the belt by the tension roller 4 on one side, and the other image is formed. On the side, the back surface of the belt photoreceptor 10 is contacted at nine locations of the backup members 41, 42 and the auxiliary backup member 43 of Y, M, C and K, respectively, and rotates at a constant speed with a large winding angle. The belt photoconductor 10 is rotated clockwise at a constant speed by the driving roller 1.

The backup member 41 is provided at the developing position (the developing position of K in the present embodiment) which is disposed on the back surface of the belt photoconductor 10 and is located at the most downstream side in the moving direction of the belt photoconductor 10. Between the second rotating roller 3 disposed further downstream of the backup member 41,
Similarly, an auxiliary backup member 43 that is in contact with the back surface of the belt photoconductor 10 is provided on the support 40 and is disposed. As shown in FIG. 6, the belt photoconductor 10 is moved by the auxiliary backup member 43. The angle α that is bent in the direction (the angle bent in the direction of movement of the belt photoconductor 10 from the auxiliary backup member 43 to the second rotating roller 3) α is determined by the backup member 41.
0 is set to be larger than the angle bent in the moving direction of the belt photoconductor 10 (the angle bent in the moving direction of the belt photoconductor 10 from the backup member 41 to the auxiliary backup member 43) β. The deflection of the roller member is absorbed by the auxiliary backup member 43 so that the deflection of the second rotating roller 3 is not directly transmitted to the backup member 41.

The above description is based on the fact that the backup member 42 at the scanning position (the scanning position of Y in the present embodiment) disposed at the most upstream position in the moving direction of the belt photoreceptor 10.
An auxiliary backup member (not shown) that contacts the back surface of the belt photoreceptor 10 may be disposed between the backup member 42 and the first rotating roller 2 disposed further upstream of the backup member 42. The angle at which the belt photoconductor 10 is bent in the direction of movement of the belt photoconductor 10 by the auxiliary backup member (not shown) (the angle at which the belt photoconductor 10 is bent in the direction of movement of the belt photoconductor 10 from the first rotating roller 2 to the auxiliary backup member). )
Is set larger than the angle at which the belt photoconductor 10 is bent in the direction of movement of the belt photoconductor 10 by the backup member 42 (the angle at which the belt photoconductor 10 is bent in the direction of movement of the belt photoconductor 10 from the auxiliary backup member to the backup member 42). The swing of the roller member at the first rotating roller 2 can be absorbed by an auxiliary backup member (not shown) so that the swing of the first rotating roller 2 is not directly transmitted to the backup member 42.

As described above, the backup member is prevented from swaying due to the sway of the roller member which stretches the belt-shaped image carrier, and the belt-shaped image carrier is not displaced at the developing position or the scanning position, and a good image is obtained. Provided are a process cartridge and an image forming apparatus on which formation is performed.

In the description of the above embodiment, the backup members 41 and 42, the auxiliary backup member 43,
Although the opposing rib members 141 and 142, the auxiliary rib 44, the opposing auxiliary rib 144, and the like are formed in a flat plate shape, the present invention is not limited to this as long as the die can be cut.

[0042]

According to the first to third aspects of the present invention, there is provided a process cartridge in which a backup member having no warp is molded and a developing position and a scanning position are accurately set.

According to the fourth to sixth aspects, there is provided an image forming apparatus in which a backup member without a warp is molded and a developing position and a scanning position are accurately set.

According to the seventh or eighth aspect, the backup member is prevented from swinging due to the swing of the roller member which stretches the belt-shaped image carrier, and the displacement of the belt-shaped image carrier at the developing position or the scanning position is prevented. There is provided a process cartridge in which good image formation is achieved without generating.

According to the ninth to twelfth aspects, the backup member is prevented from oscillating due to the sway of the roller member which stretches the belt-shaped image carrier, and the positional deviation of the belt-shaped image carrier at the developing position and the scanning position is prevented. There is provided an image forming apparatus in which good image formation is achieved without generating.

[Brief description of the drawings]

FIG. 1 is a cross-sectional configuration diagram of a color image forming apparatus showing an embodiment of an image forming apparatus having a process cartridge according to the present invention.

FIG. 2 is a detachable view of the process cartridge from the image forming apparatus.

FIG. 3 is a configuration diagram of a process cartridge.

FIG. 4 is a partially enlarged perspective view of a resin casing.

FIG. 5 is an explanatory diagram illustrating a state where a developing unit and a scanning unit are opposed to a belt-shaped image carrier.

FIG. 6 is a partially enlarged view showing an angle formed between a backup member and an auxiliary backup member of FIG. 5 with respect to a belt-shaped image carrier.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Drive roller 2 1st rotation roller 3 2nd rotation roller 10 Belt photoreceptor 11 Scorotron charger 12 Exposure optical system 13 Developing device 40 Support column 41, 42 Backup member 43 Auxiliary backup member 44 Auxiliary rib 100 Image forming apparatus 140 Resin casing 141, 142 Opposing rib member 144 Opposing auxiliary rib 300 Process cartridge

Claims (12)

[Claims] 1. A process cartridge comprising: a belt-shaped image carrier; a plurality of roller members that stretch the belt-shaped image carrier; and a resin casing that supports the roller member. A back-up member abutting on the belt-shaped image carrier from the back side; a strip-shaped support provided with the back-up member; a backup member arranged symmetrically with respect to the support; A process cartridge, wherein the resin casing is molded integrally with an opposing rib member having a shape. 2. The backup member is provided to face the belt-shaped image carrier, and is provided to face a scanning position of scanning means for scanning a scanning light to form a latent image or the belt-shaped image carrier. 2. The process cartridge according to claim 1, wherein the process cartridge is provided at a developing position of a developing unit that develops the latent image. 3. The resin casing is formed by integrally forming an auxiliary rib member which is disposed close to the backup member and whose tip is separated from the belt-shaped image carrier. 3. The process cartridge according to 1 or 2. 4. An image forming apparatus comprising: a belt-shaped image carrier; a plurality of roller members that stretch the belt-shaped image carrier; and a resin casing that supports the roller member. A backup member that contacts the belt-shaped image carrier from the back side of the body; a band-shaped support provided with the backup member; and the backup member, which is disposed symmetrically to the backup member with respect to the support. An image forming apparatus, wherein the resin casing is molded integrally with a symmetrical opposing rib member. 5. The backup member is provided to face the belt-shaped image carrier, and is provided to face a scanning position of a scanning unit for scanning a scanning light to form a latent image or the belt-shaped image carrier. The image forming apparatus according to claim 4, wherein the image forming apparatus is provided at a developing position of a developing unit that develops the latent image. 6. The resin casing is formed by integrally forming an auxiliary rib member which is arranged close to the backup member and whose tip is separated from the belt-shaped image carrier. 6. The image forming apparatus according to 4 or 5. 7. A belt-shaped image carrier, and a scanning position of a scanning unit that scans a scanning light provided to face the belt-shaped image carrier to form a latent image, or faces the belt-shaped image carrier. A plurality of backup members that are in contact with the belt-shaped image carrier from the back side of the belt-shaped image carrier at a developing position of a developing unit that develops the latent image, and stretch the belt-shaped image carrier. A plurality of roller members,
Between the backup member and the roller member adjacent to the backup member, an auxiliary backup member that contacts the belt-shaped image carrier from the back side of the belt-shaped image carrier. A process cartridge comprising: 8. An angle at which the belt-shaped image carrier is bent in the moving direction by the auxiliary backup member is set to be larger than an angle at which the belt-shaped image carrier is bent in the moving direction by the backup member. The process cartridge according to claim 7, wherein: 9. A belt-shaped image carrier, scanning means for scanning the belt-shaped image carrier with scanning light to form a latent image, and developing the latent image formed on the belt-shaped image carrier. Developing means, at a scanning position on the belt-shaped image carrier by the scanning means or at a developing position on the belt-shaped image carrier by the developing means, the belt-shaped image carrier from the back side of the belt-shaped image carrier. A plurality of backup members that contact the body, a plurality of roller members that stretch the belt-shaped image carrier,
An auxiliary backup member that contacts the belt-shaped image carrier from the back side of the belt-shaped image carrier between the backup member and the roller member adjacent to the backup member. An image forming apparatus comprising: 10. An angle at which the belt-shaped image carrier is bent in the movement direction by the auxiliary backup member is set to be larger than an angle at which the belt-shaped image carrier is bent in the movement direction by the backup member. The image forming apparatus according to claim 9. 11. The image forming apparatus according to claim 9, wherein the backup member is located at a most downstream side in a moving direction of the belt-shaped image carrier. 12. The image forming apparatus according to claim 9, wherein the backup member is located at the most upstream side in the moving direction of the belt-shaped image carrier.