JPH04147274A - Process cartridge for image forming device - Google Patents

Abstract

PURPOSE:To enhance the assembling workabilities of a photosensitive body, and to prevent scratching and the sticking of a fingerprint to the surface of the photosensitive body by stretching a photosensitive belt to form an intermediate assembly unit, and attaching it inside a frame to form the upper part unit. CONSTITUTION:Plate spring members 36 and 37 are recessed outside and are attached to a supporting member 35, its both ends are pierced through the rotational shaft parts 18A and 19A of rollers 18 and 19, and both rollers are arranged in parallel. Then, the interval L1 of the central parts of the rollers 18 and 19 is set smaller than an interval L2 on process cartridges. Then, the photosensitive belt 17 is loosened/stretched between both rollers, and the members 36 and 37 are spread out and projected outside, to obtain the intermediate assembly unit. Next, the unit is pushed into the frame 33. At this time, the shaft 19A is abutted on an inclined cam surface 332A, and slantingly, descends, and the interval of a shaft part is made larger than the L1. The members 36 and 37 are projected inside, and the belt 17 obtains a parallel plane. Next, the obtained upper part unit is disposed on the lower part unit to form a cartridge.

Description

Detailed Description of the Invention [Industrial Application Field] The present invention provides a method in which a replaceable process cartridge including a belt-like image bearing member on which an electrostatic latent image is formed is provided in a manner that it can be inserted into and removed from an apparatus main body. This invention relates to image forming apparatuses such as printers, multi-military aircraft, facsimile machines, etc., and particularly relates to improvements in process cartridges that allow the belt-shaped image carrier to be easily stretched and assembled together with support rollers in the casing of the process cartridge. It is.

[Background of the invention]

2. Description of the Related Art As image forming apparatuses such as printers and copying machines become smaller, lighter, and more sophisticated, image forming apparatuses are becoming more dense and complex.

On the other hand, even operators who are general users can easily perform maintenance and
In order to facilitate management, an image forming apparatus has been developed that includes a process cartridge in which an image carrier and at least one image forming means such as a developing means and a cleaning means are integrated into a unit.

Image forming apparatuses such as printers and copying machines equipped with this process cartridge can be used by operators without specialized knowledge to replace the process cartridge itself when the image bearing member inside the process cartridge or the like becomes worn out or deteriorated. This makes it possible to easily maintain and manage the image forming apparatus. (Unexamined Japanese Patent Publication No. 6L-279
No. 87Q, et al.) The image carrier is mounted in a process cartridge with care taken to avoid scratches or fingerprints on the latent image forming surface of the image carrier.

[Problem that the invention seeks to solve]

When installing a belt-shaped image carrier (hereinafter referred to as a photoreceptor belt) into the housing of the process cartridge, an assembly jig or member is required to hold the photoreceptor belt in a certain state of tension. be. In particular, when assembling the photoreceptor belt by dropping it into a narrow housing from above,
The assembly work must be carried out with great care so that the photoreceptor belt does not sag or become distorted and come into contact with the inner wall of the housing or other components and be damaged. In addition, the width direction inside the housing (the direction perpendicular to the direction of rotation of the photoreceptor belt)
There are restrictions and there is little free space, making assembly work extremely difficult.

[Means for solving problems]

The present invention has been made to solve the above-mentioned problems, and an object of the present invention is to improve the ease of assembling a photoreceptor belt when assembling a process cartridge of an image forming apparatus, improve assembly accuracy, and stabilize the process. It is an object of the present invention to provide an image forming apparatus which can obtain high quality recorded images by making the cartridge more compact and by preventing the occurrence of scratches and adhesion of fingerprints on the surface of a photoreceptor belt.

The above object is to provide an image forming apparatus into which a replaceable process cartridge including a belt-like image bearing member on which an electrostatic latent image is formed can be inserted and removed. a drive roller and a driven roller that are rotated by the drive roller; a support member that is provided with a shaft support that makes it possible to lock and release each rotating shaft end of the drive roller and the driven roller; and a support member that is movably provided on a part of the support member. and a tensioning means for press-contacting and tensioning the inner surface of the belt-like image carrier to form an intermediate assembly unit, and by mounting the intermediate assembly unit in the casing of the process cartridge. The tensioning means is in a retracted state, detached from the inner surface of the belt-shaped image carrier and becomes freely rotatable, and the shaft support of the support member releases the locking of each rotating shaft end of the drive roller and the driven roller. This is achieved by a process cartridge for an image forming apparatus, which is characterized in that it is rotatable.

Further, the above object is to install the intermediate assembly unit inside the housing of the process cartridge, so that the rotating shaft end of the driven roller comes into contact with a cam surface provided inside the housing and is moved. This is achieved by a process cartridge of an image forming apparatus characterized in that the tensioning means is released from pressure.

Here, the tensioning means is, for example, a bendable spring member or a spring-biased rotatable cam member.

〔Example〕

Next, the present invention will be described based on an embodiment shown in the accompanying drawings.

FIG. 1 is a main sectional view of a color printer to which the present invention is applied, viewed from the left side. The main body IO of the device has an operation panel 11 on the front, an upper cover 12 that can be opened and closed,
It is surrounded by a toner supply cover 13, a front cover 14, etc., and a removable process cartridge 15 and a paper feed cassette 16 are provided inside.

The process cartridge 15 includes an image carrier, a developing means, a charging means, a cleaning device, and the like.

The photosensitive belt 17, which is an image carrier, has a photosensitive layer such as an organic photoconductive layer (0PC) coated on the surface of a flexible belt, and is stretched between a driving roller 18 and a driven roller 19.
Rotated clockwise.

A charging means, an exposure means, a developing means, a transfer means, and a cleaning device are arranged around the photoreceptor belt 17.

The charging means is an existing charger 21 such as a corona charger or a scorotron charger.

The developing means includes a plurality of developing devices 23a each containing a developer of a different color, for example, yellow magenta, cyan, and black toners (developer).

23b, 23c, and 23d. Each of these developing devices 2
3a to 23d have a function of developing an electrostatic latent image on the photoreceptor belt 17 into a toner image by a non-contact development method.

The cleaning blade of the cleaning device 25 is kept at a position apart from the surface of the photoreceptor belt 17 during the image forming process, and is pressed against the surface of the photoreceptor belt 17 only during cleaning after transferring the toner image to the transfer material P to clean the photoreceptor. Clean the belt 17.

The toner collection box 26 collects and stores the residual toner on the photoreceptor bell 17 that has been removed by the cleaning device 25.

In this embodiment, a photoreceptor belt 17, a charger 21, . Developing devices 23a to 23d1 containing toner of each color Cleaning device 2
5 and the toner collection box 26 are housed in an integrated process cartridge 15 to form a unit, and can be attached to and detached from the apparatus main body 10 all at once.

On the other hand, on the main body side of the image forming apparatus, when the process cartridge 15 is installed and an image can be formed, an exposure means, a transfer means, etc. are arranged around the photoreceptor belt 17.

The exposure means is a semiconductor laser writing optical system unit (hereinafter referred to as optical system unit) 22, which exposes the surface of the photoreceptor belt 17 charged by the charger 21 to form an electrostatic latent image.

The transfer means transfers the toner image formed on the photoreceptor belt 17 to a transfer material P by a transfer device 24 such as a transfer corona discharger.
Transfer on top.

The color image forming process by the color image forming apparatus having the above-described configuration is performed as follows.

First, the process cartridge 15 is inserted into the image forming apparatus main body 1.
It is loaded at a predetermined position within 0 and is ready for image formation. When an image signal of the first color outputted from an image reading device separate from the apparatus main body 10 is input to the optical system unit 22, a laser beam is generated by a semiconductor laser in the optical system unit 22. . The laser beam is rotated and scanned by a polygon mirror rotated by a drive motor, passes through an fθ lens, a linear lens, and a group of mirrors, and then is placed on the photoreceptor belt 17, which has been uniformly charged to a predetermined charge by a charger 21. It is projected onto the circumferential surface and forms a bright line.

On the other hand, regarding the sub-scanning direction, a belt index (not shown) corresponding to a specific position of the photoreceptor belt 17 is detected, or a print command signal is received, and based on this detection or command signal, A main scanning line on which modulation of the semiconductor laser by the image signal is started is determined. When scanning is started, in the main scanning direction, the laser beam is detected by an index sensor (not shown), and based on this detected signal, modulation of the semiconductor laser by the image signal of the first color is started. , a modulated laser beam scans over the surface of photoreceptor belt 17.

Therefore, main scanning by the laser beam and photoreceptor belt 1
A latent image corresponding to the color wgl is formed on the surface of the photoreceptor belt 17, which is uniformly charged by the sub-scanning during the conveyance of step 7. This latent image is developed by a developing device 23 a containing yellow toner corresponding to the first color among the developing means, and a yellow toner image is formed on the surface of the photoreceptor belt 17 . Thereafter, the photoreceptor belt 17 passes under the cleaning blade 251 which is spaced apart from the surface of the photoreceptor belt 17 while holding the yellow toner image on its surface, and then begins to form an image of the second color.

That is, the photoreceptor belt 17 on which the yellow toner image has been formed is uniformly charged again by the charger 21, and then
An image signal of color is input to the optical system unit 22,
As in the case of the first color image signal described above, writing is performed on the surface of the photoreceptor belt 17 to form a latent image. The latent image is developed by a developer 23b containing magenta toner as the second color. The magenta toner image is
It is formed in the presence of a yellow toner image that has already been formed.

Similarly, a cyan toner image is formed in the developing device 23e that stores cyan toner after forming a latent image based on the image signal of the third color, and further stores black toner after forming the latent image using the image signal of the fourth color. The photoreceptor belt 1 is
A color toner image is formed on the surface of the photoreceptor belt 17 by superimposing a black toner image on the surface of the photoreceptor belt 17 .

The color toner image formed on the surface of the photoreceptor belt 17 as described above is transferred from the paper feed cassette 16 to the paper feed roller 27.
The color toner image is supplied by the timing roller 28 and transferred onto the transfer material P in synchronization with the color toner image. The transfer device 24 performs transfer by applying a high-voltage power output having a polarity opposite to that of the toner.

The transfer material P onto which the color toner image has been transferred in this manner is reliably separated by the photoreceptor belt 17 that changes direction rapidly (with a small diameter curvature) along the drive roller 18, and is transported upward by the transport belt 29.

After the toner is melted and fixed on the transfer material P by the fixing device 30, the transfer material P is ejected onto the upper surface of the upper cover 12, which also serves as a paper ejection tray, by the paper ejection roller 31.

FIG. 2 is a perspective view of the process cartridge 15 with the top cover removed, and FIG. 83 is a side sectional view of the process cartridge 15.

A plurality of developing units 23a,
23b, 23c, and 23d are provided.

Inside each of these developing devices 23 (a"d), a developing sleeve,
A toner conveying screw and a stirring screw are mounted rotatably. Furthermore, inside each developing unit, there is a partition plate,
A magnetic thin layer forming rod, a scraper, a shielding plate for preventing toner scattering, etc. are fixedly installed.

FIG. 4 is a side sectional view of the upper unit of the process cartridge 15.

The process cartridge 15 includes the developing devices 23a to 23a.
23d, charger 21. A lower unit consisting of a cleaning device 25 and a lower housing 32, and a photoreceptor belt 17.
Drive roller 18. It is composed of a driven roller 19 and an upper unit consisting of an upper housing 33, and these upper and lower units are fixed and integrated.

Both sides of the upper housing 33! The portion 330 is provided with a vertical guide groove 331 on the left side in FIG. 4 and a wide guide groove 332 with a cam on the right side in the figure and having an inclined cam surface 332A.

The rotation shaft portion 18^ of the drive roller 18 is inserted into and supported by the vertical guide groove 331. The cam-equipped guide groove 332 also includes a rotating shaft portion 19A of the driven roller 19.
is penetrated and supported. A coil spring 34 is stretched between the end of the rotating shaft of the driven roller 19 and the upper housing 33, and by spring biasing the driven roller 19 to the right, the driving roller 18 and the driven roller 19 are The wound photoreceptor belt 17 is loosened and stretched.

FIG. 5 shows the photoreceptor bell) 17. FIG. 3 is a side sectional view of the intermediate assembly unit in a state before the driving roller 18 and the driven roller 19 are mounted on the upper housing 33;

The intermediate assembly unit includes the photoreceptor belt 17.degree. drive roller 18. A driven roller 19, a support member 35 for assembling these members, and leaf spring members (stretching members) 36, 3
It is composed of 7 and forms a single unit.

U-shaped groove-shaped shaft support portions 351 and 352 are provided at both left and right ends of the supporting member 35 in the drawing. The rotating shaft portions 19A of the two are removably inserted into each other. Additionally, four protrusions 353 and 354 protrude above and below the intermediate portion of the support member 35. A plate spring member 36 is supported on the upper surface of the two upper protrusions 353 so as to be movable left and right. In the same way, lower two protrusions 3
A leaf spring member 37 is supported on the lower surface of 54 so as to be movable laterally.

The leaf spring members 36 and 37 have a gently curved surface,
Initially, it is attached to the support member 35 so as to form an outward concave shape (indicated by broken lines in the figure).

The rotating shaft portion 18A of the drive roller 18 and the rotating shaft portion 19'A of the driven roller 19 are respectively inserted into the shaft supports 351 and 352 at both ends of the support member 35 to which the leaf spring members 36 and 37 are attached in this manner. If it hits both rollers 18.19
are arranged in parallel. Note that an axial stopper (not shown) is provided on the support member 35, and the 100 roller 1
By making the stepped portions of the rotating shaft portions 18A and 19A of 8.19 butt against each other, the axial positions of both rollers can be regulated and set. Both these rollers18.19
The center axis distance L1 when both rollers 1 are held parallel is
The shaft support interval of the support member 35 is set so that it is smaller than the center axis interval L2 when 8.19 is installed at a predetermined position of the process cartridge 15.

The photoreceptor bell 17 is wound on the same surface of the driving roller 18 and driven roller 19 that are held parallel in this manner.

However, due to the shaft supporting distance Ll<L2, the photoreceptor belt 17 can be easily wound between the rollers 18 and 19.
In addition, it is in a loose state due to loosening.

In this way, both rollers fi11.19 are attached to the supporting member 35.
When the photoreceptor belt 17 is held in a relaxed state and the plate spring members 36 and 37 are expanded outward to form a convex state as shown by the solid line in the figure, the photoreceptor belt 1
7 is extended outward by the expansion force of the leaf spring members 36 and 37, and becomes an expanded curved surface shape as shown in FIG. 5, and is integrated with the stop.

Next, the intermediate assembly unit is grasped and pushed into the upper housing 33 to be installed. As a result, the rotating shaft portion 18A of the drive roller 18 is inserted into the vertical guide groove 331 and lowered.
At the same time, the rotating shaft portion 19A of the driven roller 19 descends along the inner wall of the cammed guide groove 332.

At this time, the rotating shaft portion 19A comes into contact with the inclined cam surface 332 of the guide groove 332 and descends obliquely.
is the direction away from the left rotation axis 18A (to the right in the figure)
The distance between the two rotary shaft portions increases from the shaft support distance L1. As a result, both rotating shaft portions 18A.

19A are respectively disengaged from the pivot supports 351 and 352 and separated, and the locking is released.

On the other hand, the rotating shaft portion 19A of the driven roller 19 is connected to the vertical guide groove 3.
The stretched photoreceptor belt 17 is also pulled to the right as it moves away from the rotating shaft portion 18A of the drive roller 18 which is fitted on the belt 31 and is located at a predetermined position, pressing the intermediate portion of the belt. The leaf spring members 36 and 37 are pressed inward. Due to the pressing force exerted by the belt 17, the leaf spring members 36, 37 gradually bend inward, and when they exceed the neutral position, they suddenly become convex inward as shown in FIG. 4 and stop. In this stopped state, the leaf spring members 36 and 37 are separated from the inner surface of the photoreceptor belt 17 and are not in contact with each other, and the upper and lower surfaces of the photoreceptor belt 17 are stretched as parallel planes.

The upper unit assembled in this manner is placed and fixed on the lower unit having the developing units 23 (a-d) and the like. Furthermore, spacer plates 20a, 20b, 20c, 20d are provided inside the photoreceptor belt 17.
A backup plate 20e is installed on both side walls 330, and the position is adjusted and fixed. As a result, the photoreceptor belt 17 is stretched downward against the biasing force of the coil spring (tension spring) 34, and the rotating shaft portion 19A is moved to the left, so that the distance between the shafts is slightly narrowed.

In this state where the upper and lower units are combined, the drive roller 1g
, the driven roller 19 is rotatable apart from the support member 35, and the photoreceptor belt 17 is rotated apart from the leaf spring member 36.3.
7 and can be rotated freely.

FIG. 6 is a sectional side view of an intermediate assembly unit showing another embodiment of the process cartridge according to the present invention. In this embodiment, 1. A cam member 38 is rotatably provided in place of the leaf spring member. The cam member 38
When the intermediate assembly of the photoreceptor belt 17 is completed, the photoreceptor belt 17 is held in an upright state as shown by the solid line in the figure, and the photoreceptor belt 17 is held in a bulged shape.

When this intermediate assembly unit is pushed into the upper housing, the cam member 38 is rotated and tilted by a regulating member (not shown) to the state shown by the broken line, and the rollers 18
．． 19 and tensioning of the photoreceptor belt is performed.

FIG. 7 is a side sectional view of the upper housing of the process cartridge according to the present invention. The lower leaf spring member 37 in this embodiment is the leaf spring member 37 shown in FIGS. 4 and 5.
It is similar to , and is supported in a flexible manner. However, since both ends of the upper leaf spring member 3G are fixed to the upper surface of the projection 353 of the support member 35 and are immovably attached, the reverse curvature occurs despite the movement of the rotation shaft 19A of the driven roller 19. The elastic force is maintained by supporting both ends. Therefore, instead of the fill spring (tension spring) 34,
It can be used for tensioning the photoreceptor belt 17 to prevent it from loosening.

In this example, as an image forming process, an image forming method was described in which a color toner image is formed on a photoreceptor belt and then transferred to a transfer material in one step. It may also be a color imaging method in which a toner image is transferred by using the same method. Further, it is also applicable to a normal monochrome printer using a monochrome process.

〔Effect of the invention〕

As described in detail above, the process cartridge of the image forming apparatus of the present invention can improve the workability of assembling the photoreceptor belt when assembling the process cartridge, as well as improve and stabilize the assembly accuracy. An image forming apparatus that prevents scratches and fingerprints from forming on the belt surface and produces high-quality recorded images was obtained. Additionally, the space for mounting the photoreceptor belt is reduced, making it possible to form a compact process cartridge.

[Brief explanation of the drawing]

FIG. 1 is a side sectional view of an image forming apparatus according to the present invention, FIG. 2 is a perspective view of a process cartridge according to the present invention, FIG. 3 is a side sectional view of the process cartridge, and FIG. 4 is a top unit of the process cartridge. 5 is a side sectional view of an intermediate assembly unit of the process cartridge, FIG. 6 is a side sectional view showing another embodiment of the process cartridge according to the present invention, and FIG. 7 is a side sectional view of the intermediate assembly unit of the process cartridge. FIG. 7 is a side sectional view showing still another embodiment of the process cartridge. lO...Device body 15...Process cartridge 17...Photoconductor bell) 1g...Drive roller 18A...Drive roller rotation shaft portion 19...Followed roller 19A...Followed roller rotation shaft portion 23a, 23b, 23c, 23d--Developer 32...
- Lower housing 33... Upper housing 34... Coil spring (tension spring) 35... Support members 36, 37... Leaf spring member (tension member) 38...
Cam member (tension member) 330...Both side wall parts 331...Vertical guide groove 33
2...Guide groove with cam 332A...Slanted cam surface

Claims (4)

[Claims] (1) In an image forming apparatus into which a replaceable process cartridge including a belt-shaped image bearing member on which an electrostatic latent image is formed can be inserted and removed, the belt-shaped image bearing member and the belt-shaped image bearing member are wound. A drive roller and a driven roller to be rotated; a support member provided with a shaft support that enables locking and detachment of each rotating shaft end of the drive roller and driven roller; and a support member provided movably on a part of the support member. , an intermediate assembly unit is formed by integrating tensioning means for tensioning the inner surface of the belt-like image carrier, and the tensioning means is installed in the housing of the process cartridge. The installation means is in a retracted state and detached from the inner surface of the belt-like image carrier and becomes freely rotatable, and the shaft support of the support member releases the locking of each rotating shaft end of the drive roller and the driven roller. A process cartridge for an image forming apparatus that is rotatable. (2) By installing the intermediate assembly unit in the housing of the process cartridge, the rotating shaft end of the driven roller comes into contact with a cam surface provided in the housing and is moved, thereby causing the tensioning means to move. 3. The process cartridge for an image forming apparatus according to claim 1, wherein the pressure contact of the process cartridge is released. (3) The process cartridge for an image forming apparatus according to claim 1 or 2, wherein the tensioning means is a bendable spring member. (4) The process cartridge for an image forming apparatus according to claim 1 or 2, wherein the tensioning means is a spring-biased rotatable cam member.