JPH04340975A - Process cartridge for color image forming device - Google Patents

Abstract

PURPOSE:To improve the accuracy of the relative position of the driving shafts of respective developing devices by constituting a fixed supporting plate for positioning the shaft ends of the respective driving shafts of a developer carrier, a developer supply member and a developer stirring member as one plate and fixing it in the housing of the developing device. CONSTITUTION:On the side surface of the housing 27 of a process cartridge 20, gear groups are fitted on the bearings of the respective driving shafts of the plural developing devices, which are projected to the outer side than the respective bearings. The tip of the driving shaft is supported by the bearing provided on one driving supporting plate 26A which is in common among the respective developing devices, and the driving supporting plate is fixed on the side wall of the housing 27. Namely, the one driving shaft end of the developer supply member 233 is born and supported on both sides by the bearings 278 and 279 and the one shaft end of the developer carrier 231 where the gear G29 is provided is rotatably supported by the bearing of the housing 27. Both shaft ends of a magnetic roller 236 inside the carrier are fixedly supported to both of the right and left side plates of the housing 27. In the same manner, the one driving shaft end of the developer stirring member is born and supported on both sides by the bearings. Thus, the eccentric rotation of the driving shaft is prevented.

Description

[Detailed description of the invention]

0001

[Field of Industrial Application] This invention relates to a color image forming apparatus such as an electrostatic recording type color electrophotographic copying machine or a color printer, and particularly relates to an image carrier and a developing device on which an electrostatic latent image is formed. The present invention relates to a process cartridge for a color image forming apparatus in which the process cartridge is made into a unit and is replaceable and can be inserted and removed.

0002

2. Description of the Related Art As image forming apparatuses such as printers and copying machines have become more compact, lighter, and more functional, they have become more dense and complex.

[0003] On the other hand, in order to allow operators, who are general users, to easily perform maintenance and management, image forming apparatuses having a process cartridge in which an image bearing member and at least one means of image forming means such as a developing means and a cleaning means are integrated into a unit. A forming device was developed. In image forming apparatuses such as printers and copying machines equipped with this process cartridge, when the image bearing member inside the process cartridge becomes worn out or deteriorated, the process cartridge itself can be replaced, allowing operators without specialized knowledge to easily image the image. This makes it possible to easily maintain and manage the forming device. To this end, a guide member for the process cartridge is provided in the main body of the apparatus, and the process cartridge can be loaded by simply inserting the process cartridge along this guide member so as to obtain an optimal image.

0004

[Problems to be Solved by the Invention] A process cartridge used in a color image forming apparatus is equipped with a plurality of developing devices, and each developing device contains color developers of different colors, such as yellow, magenta, and cyan. A color image is formed using the toners of each color, ie, black.

In each developing unit of the process cartridge, various members such as a developing sleeve, a magnet roll, a developer transport stirring screw, a developer supply screw, etc. are positioned and arranged, and are driven from the drive source of the apparatus main body via a transmission means. be rotated.

[0006] The shaft bodies of the above-mentioned members must be arranged with high accuracy within the process cartridge, and must be stably rotated with light torque by transmission of driving force through a gear train. Furthermore, since the process cartridge is a consumable item and can be replaced with other process cartridges, it is important to maintain the accuracy of the drive system.

Furthermore, when the process cartridge is removed from the main body of the apparatus, the gear train that drives and rotates each shaft of each developing device of the process cartridge is exposed, which poses operational danger. Furthermore, when the process cartridge is placed on a flat platform, the outer diameter of the tooth tip of the gear may collide with the platform, damaging the gear or deforming the gear shaft or bearing.

[0008]

[Means for Solving the Problems] The purpose of the present invention is to improve the process cartridge which has the above-mentioned problem. It is an object of the present invention to provide a process cartridge that improves accuracy, protects a large number of gears provided at the ends of these shaft bodies, and prevents danger when attaching and detaching the process cartridge.

A process cartridge of a color image forming apparatus according to the present invention that achieves the above object includes an image carrier that is rotatably held and on which an electrostatic latent image is formed, and a color toner by developing the electrostatic latent image. A process cartridge is a unitized image forming means including a plurality of developing devices that form an image.
In a color image forming apparatus that can be inserted into and removed from an apparatus main body, in each of the plurality of developing devices, a central axis of a fixedly arranged magnet body having a plurality of magnetic poles, and a surface having the magnet body therein. a drive shaft for a rotatable developer carrier carrying developer thereon;
Positioning each shaft end of a drive shaft of a rotatable developer supply member that supplies developer to the developer carrier and a drive shaft of a rotatable developer stirring member that supplies and stirs developer to the supply member. The present invention is characterized in that the fixing support plate is a single piece common to each developer, and the fixing support plate is fixed to the developer housing.

Further, in the process cartridge of the present invention, the fixed support plate is formed in a shape that covers the outer periphery of a plurality of gears attached to shaft ends of drive shafts of each of the developing units that protrude outside the process cartridge. , and has a shape that protrudes downward from the bottom outer wall of the process cartridge, so that when the process cartridge is taken out of the main body of the color image forming apparatus and placed on a flat part, the outer diameter of the gear is protected. It is characterized by the following.

[0011]

Embodiments Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

FIG. 1 is a main sectional view of a color printer to which the developing method of the present invention is applied, viewed from the left side. The apparatus main body 10 is surrounded by an operation panel 11, an openable and closable upper cover 12, a toner supply cover 13, a front cover 14, etc. on the front side, and inside the opening of the apparatus main body 10 is a removable process cartridge 20. A paper feed cassette 30 is provided.

The process cartridge 20 includes an image carrier,
It consists of a developing means, a charging means, a cleaning device, etc.

The photosensitive belt 21, which is an image carrier, has a flexible belt surface coated with a photosensitive layer such as an organic photoconductive layer (OPC), and includes a driving roller 22A and a driven roller 22B.
and rotated clockwise.

Around the photoreceptor belt 21, charging means,
An exposure means, a development means, a transfer means, and a cleaning device are provided.

The charging means is an existing charger 24 such as a corona charger or a scorotron charger.

The developing means uses different color developers, such as yellow, magenta, cyan, and black color toners (
A plurality of developing units 23a and 2 each containing a developer (developing agent).
3b, 23c, and 23d. Each of these developing devices 23a~
23d has a function of developing an electrostatic latent image on the photoreceptor belt 21 into a toner image using a non-contact development method.

The cleaning blade 251 of the cleaning device 25 is kept at a position apart from the surface of the photoreceptor belt 21 during the image forming process, and is pressed against the surface of the photoreceptor belt 21 only during cleaning after transferring the toner image to the transfer material P. The photoreceptor belt 21 is then cleaned.

The toner collection box 26 collects and stores the residual toner on the photoreceptor belt 21 that has been removed by the cleaning device 25.

In this embodiment, the photoreceptor belt 21, charger 24, and
Each process section of the developing devices 23a to 23d containing toner of each color, the cleaning device 25, and the toner collection box 252 is housed in the integrated process cartridge 20 to form a unit, and can be attached to and detached from the apparatus main body 10 all at once. Can be done.

On the other hand, on the main body side of the image forming apparatus, when the process cartridge 20 is installed and an image can be formed, exposure means, transfer means, etc. are arranged around the photoreceptor belt 21.

The exposure means is a semiconductor laser writing optical system unit (hereinafter referred to as optical system unit) 40, which exposes the surface of the photoreceptor belt 21 charged by the charger 24 to form a charged latent image.

The transfer means 50 transfers the toner image formed on the photosensitive belt 21 onto the transfer material P using the transfer drum 51 and the transfer device 54.

The process of forming a color image using the color image forming apparatus having the above configuration is performed as follows.

First, the process cartridge 20 is loaded in a predetermined position within the image forming apparatus main body 10, and is ready for image formation. When a first color image signal output from an image reading device separate from the main body 10 of the apparatus is input to the optical system unit 40, a laser beam is generated by a semiconductor laser in the optical system unit 40. . The laser beam is rotated and scanned by a polygon mirror 42 rotated by a drive motor 41,
The light is projected through the cylindrical lens 43, the fθ lens 44, and the mirrors 45 and 46 onto the circumferential surface of the photoreceptor belt 21, which has been uniformly charged to a predetermined charge by the charger 24, to form a bright line.

On the other hand, regarding the sub-scanning method, a belt index (not shown) corresponding to a specific position on the photoreceptor belt 21 is detected, or a print command signal is received, and this detection or command signal is used as a reference. Then, the main scanning line on which modulation of the semiconductor laser by the image signal starts is determined. When scanning is started, in the main scanning direction, a laser beam is detected by an index sensor (not shown), and based on this detected signal, a semiconductor laser beam based on an image signal of the first color is directed to the photoreceptor belt. Scan over the surface of 21.

Therefore, a latent image corresponding to the first color is formed on the uniformly charged surface of the photoreceptor belt 21 by the main scanning by the laser beam and the sub-scanning by the conveyance of the photoreceptor belt 21. This latent image is developed by a developing device 23a 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 21.

Thereafter, the photoreceptor belt 21 is rotated while keeping the yellow toner image on its surface.
After passing under the cleaning blade 251 which is spaced apart from the surface of the image forming apparatus, the second color image formation begins.

That is, the photoreceptor belt 21 on which the yellow toner image has been formed is uniformly charged again by the charger 24, and then the image signal of the second color is transferred to the optical system unit 4.
0, and as in the case of the image signal of the first color described above, writing is performed on the surface of the photoreceptor belt 21 to form a latent image. The latent image is developed by a developer 23b containing magenta toner as the second color. A magenta toner image is formed in the presence of a previously formed yellow toner image.

Similarly, after forming a latent image using the third color image signal, a cyan toner image is formed in the developing device 23c containing cyan toner, and furthermore, after forming a latent image using the fourth color image signal, a black toner image is formed. A color toner image is formed on the surface of the photoreceptor belt 21 by superimposing a black toner image on the surface of the photoreceptor belt 21 using a developing device 23d containing toner.

A direct current or even an alternating current bias is applied to the developing sleeves 231a to 231d (see FIG. 2) of each of the developing units 23a to 23d, and reverse development is performed without contact with the photoreceptor belt 21 whose base is grounded. is now being carried out. Incidentally, for this non-contact development, either a two-component developer or a one-component developer can be used. When using a one-component developer, there is no need to provide a toner hopper separate from the developing section, allowing for downsizing, but a development method using a two-component developer is superior in terms of development stability. Therefore, it is preferable in terms of color reproduction.

As described above, the color toner image formed on the surface of the photoreceptor belt 21 is transferred to a transfer material P that is supplied from a paper feed cassette 30 by a paper feed roller 31 and is timed with the color toner image by a timing roller 32. transcribed into. The transfer device 50 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 way moves sharply (small diameter curvature) along the drive roller 22A.
They are reliably separated by the photoreceptor belt 21 which changes direction, and are conveyed upward by a conveyor belt 60 having a built-in suction means 61.

After the toner is melted and fixed on the transfer material P by heat and pressure contact between the fixing roller 71 and the pressure roller 72 of the fixing device 70, the transfer material P is transferred to the upper surface of the upper cover 12, which also serves as a paper ejection tray, by the paper ejection roller 73. be discharged.

FIG. 2 is a side sectional view of the process cartridge 20.

The process cartridge 20 includes a developing device 23
a, 23b, 23c, 23d, a charger 24, a cleaning device 25, etc., and a drive roller 22 that rotates the photoreceptor belt (image carrier) 21 above it.
A, driven roller 22B, and spacing member 28a
, 28b, 28c, 28d, and an upper unit consisting of a back plate 28e, etc., and has a structure that can be separated and combined.

Near the bottom of the housing 27 of the lower unit are a plurality of developing units 23a, 23b, 23c, 2.
The 3d casing is a developer tank formed into a concave shape. Inside each of these developing tanks, there is a developing sleeve (developer carrier) 2.
3la, 23lb, 23lc, 23ld, and toner replenishment stirring screws (developer stirring members) 232a, 232b.
, 232c, 232d, and the developer stirring supply screw (
developer supply member) 233a, 233b, 233c, 23
3d is mounted on both side surfaces of the housing 27 so as to be rotatable.

[0038] The developing devices 23a, 23b, 23c, 23
d all have similar structures, and one representative developing device (23) will be described with reference to FIG.

A magnet body (magnet roller) 236 having a plurality of magnetic poles is fixed to both side surfaces of the housing 27 inside the concentrically rotatable developer carrier 23l. The magnet body 236 includes a main magnetic pole facing the image carrier 21 and a plurality of (for example, six as shown in the figure) sub magnetic poles.

A non-magnetic partition plate 23 is provided between the developer stirring member 232 and the developer supplying member 233 in the developing device 23.
4 is fixed. A peeling member (scraper) 235 is attached to the partition plate 234, and its tip is lightly pressed against the cylindrical surface of the developing sleeve 231. In addition, 2
37 is a shielding plate for preventing toner scattering.

In the vicinity of the developing sleeve 231, a magnetic and rigid thin layer forming rod 29 is supported by a holder and pressed by an elastic member to come into pressure contact with the developing sleeve 231, thereby forming a developer layer regulating means. are doing.

The developing sleeve 231 and the photosensitive belt 2
1 is maintained at all times by a roller (not shown) coaxially provided at the shaft end of the developing sleeve 231 abutting the spacing plate 28 that slides on the photoreceptor belt 21 .
It is maintained at a constant gap of around 5 mm.

Toner replenished from the toner storage device (toner hopper) is sent to a toner replenishment agitation screw 232, and further stored in a developer tank in advance by a developer agitation supply screw 233 that rotates in opposite directions. After being thoroughly stirred and mixed with a two-component developer D consisting of a magnetic carrier and toner, the developer is sent to the developing sleeve 231.

A magnet roller 236 having a fixed magnetic pole is disposed inside the developing sleeve 231 that is driven and rotated, and the rotating developing sleeve 231 and the magnet roller 236 cause the developing material D to be transferred to the developing sleeve 231. It adheres to the top in a layer and is transported in the direction of the arrow.
A predetermined thin layer is formed by passing through the pressing position of the thin layer forming rod 29.

Thereafter, after the development of the electrostatic latent image on the developing area is completed, the remaining developer D on the developing sleeve 231 is returned into the housing 27 of the developing device 23, and the non-magnetic field portion Q, that is, the magnetic flux When the developer D reaches a position where the density is almost zero and the developer D can fall under its own weight, the developer D is scraped off from the circumferential surface of the developing sleeve 231 by the scraper 235, and then uniformly stirred by the screws 232 and 233 again. , scattered on the developing sleeve 231,
Development is performed continuously.

FIG. 3 is a longitudinal sectional view of the process cartridge 20, and FIG. 4 is a sectional view taken along line AA of the developing device 23.

A drive roller 22A is provided on the side surface of the process cartridge 20 to rotate the photoreceptor belt 21.
A drive gear G14 connected to is provided. The drive gear G14 is connected to the main body 1 of the device via a gear train that can be moved into and out of contact, which will be described later.
It is connected to the drive motor M1 in 0. Further, the other drive motor M2 in the apparatus main body 10 is connected to the developer stirring member 232 drive gear G27 of the developing unit 23 via a gear train.
The developer carrier 231 drive gear G29, waste toner screw drive gear, etc. are driven and rotated. The drive gear G27
meshes with a drive gear G28 fixed to the shaft end of the developer supply member 233 to transmit power.

On the other hand, a housing 27 of the process cartridge 20 is located inside the process cartridge storage chamber of the apparatus main body 10.
A guide rail 201 that suspends the process cartridge 20 by fitting the flange portion 271 therein, a plurality of motors M1 and M2 (not shown), the drive gears G27, G, and G14 of the process cartridge 20, and the waste toner screw drive gear. A gear group corresponding to the gears is arranged.

FIG. 5 is a configuration diagram showing the drive system of the image forming section of the process cartridge 20 from the left side. FIG. 6 is a configuration diagram showing the drive system in a state where the cartridge 20 is separated from the main body 10 of the image forming apparatus. FIG. 7 is a plan view of the drive system on the device main body 10 side. Note that in these figures, the circles representing each gear represent pitch circles.

The drive system of the photoreceptor belt 21 includes a motor M.
A driving force from 1 is used. Gear G12 is motor M
It is disposed so as to mesh with the gear G11 of the first shaft. Further, when the process cartridge 20 is in a position where image formation is possible, a drive roller 22A that conveys the photoreceptor belt 21
A drive gear G14 provided coaxially with the main body 10 meshes with a gear G13 that rotates together with a gear G12 on the device main body 10 side. That is, the rotation of the motor M1 is transmitted to the drive gear G14 via the gear G11, the gear G12, and the gear G13, and is adjusted to an appropriate rotational speed, and the rotation speed of the motor M1 is further adjusted to an appropriate rotation speed.
The photoreceptor belt 21 is conveyed by rotating the photoreceptor belt 2A in the counterclockwise direction in the figure together with the drive gear G14.

Next, the driving of the developing units 23a to 23d will be explained.

A motor M2 is used in this drive system. The rotational force of motor M2 is transmitted to gear G22 via gear G21 on the shaft of motor M2. Further, the signal is transmitted to a gear G23 provided coaxially and integrally with the gear G22, and further branched and transmitted to a gear G24b and a gear G24c on both sides. The gears G24b and G24c are further connected to the outer gear G2.
5a and G25b, gears G24a and G2
4d.

Each of the gears G24a to G24d is connected coaxially with the gears G24a to G24d via open type spring clutches Ka to Kd in order to transmit rotation in only one direction.
Furthermore, when the process cartridge 20 is in a position where image formation is possible, the gear G is engaged with the developing unit drive gears G27a to G27d provided on the process cartridge 20.
26a to G26d are arranged. The rotational force transmitted to the developing unit drive gears G27a to G27d is transmitted to the gears G28a to G2 provided in the process cartridge 20.
8d to the developing sleeves 231a to 231d and the stirring screws 232a to 232d, and the developing device 23a
~23d is driven. That is, the rotation of motor M2 is
Gear G2 via gear G21, gear G22, and gear G23
4b and gear G24c, and further to gear G25a.
, gear G24a and gear G24 via gear G25b.
Transmit to b. Then, if necessary, clutch Ka~K
d is connected and transmitted to developer drive gears G27a to G27d, thereby driving the developers 23a to 23d. Note that during image formation, the developing devices 23a to 23d are driven only to the developing devices corresponding to each color of image formation, and when the process cartridge 20 is installed or removed, the developing devices 23a to 23d are not driven. It is better to do this.

FIG. 8 is a perspective view of the process cartridge 20 seen from the right side, and FIG. 9 is a side view.

On the right side of the casing 27 of the process cartridge 20, shaft ends of the drive shafts of the plurality of developing units 23a to 23d protrude outward from the respective bearings, and the gear group is fitted therein. .

The leading end of the drive shaft is fitted into and supported by a bearing provided on a single drive support plate 26A common to each developing unit. The drive support plate 26 is fixed to the side wall of the housing 27.

That is, developer stirring member 232 (a to d
) is supported by a bearing 276 provided on the housing 27, a gear G27 is fixed to the protrusion shaft, and the drive shaft tip is provided on the drive support plate 26A. It is fitted and supported by a bearing 277. Therefore, one shaft end of the drive shaft is not supported on a cantilever, but supported on both sides by the bearings 276 and 277, which prevents eccentric movement during rotation of the drive shaft, variation in meshing between gears, etc. There will be no change in the distance between the two.

Since one drive shaft end (four shafts) of the developer supplying members 233 (a to d) also has a double-supported structure with the same bearings 278 and 279 as described above, the above-mentioned problem is solved.

Further, the drive shaft ends (four shafts) having one gear G29 of the developer carriers 231 (a to d) are connected to the housing 27.
It is rotatably supported by a bearing of the housing 27, but both shaft ends of the magnet body (magnet roller) 236 inside the housing 27
It is fixedly supported through holes in the left and right side plates of the.

Gear trains G2 (a to d) and G28 (a to d) arranged on one side of the process cartridge 20
) and the fixed shaft end of the developer carrier 236 are formed of a single metal plate common to all the developers, and are fixed to the developer housing 27. All the bearings (277
etc.) and holes are machined at the same time, and their relative positions are maintained with high precision.

Furthermore, since the fixed support plate 27A is shaped to cover all the gears, when the process cartridge 20 is removed and operated, the gears will not be accidentally touched by equipment or fingers, making it safe. Further, the lower end of the fixed support plate 27A is shaped to protrude downward from the outer diameter of the tooth tips of all the gears. This is because when the process cartridge 20 is taken out from the apparatus main body 10 and placed on a flat table, the fixed support plate 27
The lower end surface of A comes into contact with the base, preventing the gear train from directly hitting the base and being damaged or deformed.

On the other hand, a fixed support plate 26B is fixed to the other side of each developing housing 27 of the process cartridge 20, and supports the other shaft end of the developer carrier 236 through the plate. By setting the lower end surface of the fixed support plate 26B at the same height as the front fixed support plate 26A, the process cartridge 20 can be placed horizontally on the table.

In this embodiment, as an image forming process, an image forming method was described in which a color toner image is formed on an image carrier (photoreceptor belt) and then transferred to a transfer material in one step. A color imaging method may be used in which toner images are transferred onto a transfer material on a drum in an overlapping manner. Furthermore, although the non-contact development method has been described as a developing method, the present invention is not limited to this non-contact development, but can also be applied to contact development. Furthermore, the present invention is also applicable to a developing device that uses a one-component developer in addition to a two-component developer.

[0064]

As described in detail above, the process cartridge of the color image forming apparatus of the present invention improves the relative positional accuracy of each drive shaft of a plurality of developing units, stabilizes the drive torque, and enables smooth drive rotation. Ru. Further, the assembly, adjustment, and holding of the developing device are also facilitated. Furthermore, since the gear train is protected by a fixed support plate, when the process cartridge is removed from the main body of the device, the gear train collides with other equipment, resulting in property damage or deformation, or injury to the fingertips of the person. This also prevents accidents.

[Brief explanation of the drawing]

FIG. 1 is a configuration diagram of a multicolor image forming apparatus equipped with a developing device according to the present invention.

FIG. 2 is a side sectional view of a process cartridge of the multicolor image forming apparatus.

FIG. 3 is a longitudinal sectional view of the process cartridge of the present invention.

FIG. 4 shows A- of the developing device of the process cartridge.
A sectional view.

FIG. 5 is a configuration diagram of the drive system of the image forming section of the process cartridge.

FIG. 6 is a configuration diagram of each drive system of the image forming apparatus and the process cartridge.

FIG. 7 is a plan view of the drive system of the image forming apparatus.

FIG. 8 is a perspective view of the process cartridge.

FIG. 9 is a side view of the process cartridge.

[Explanation of symbols]

10...Device body
20... Process cartridge 21... Photoreceptor belt (image carrier) 23a, 23b, 23c, 23d... Developing device (developing device)
231 (231a, 231b, 231c, 231d)...
Developer carrier (developing sleeve) 232 (232a, 232b, 232c, 232d)...
Developer stirring members 233 (233a, 233b, 233c
, 233d)...Developer supply member 236 (236a, 23
6b, 236c, 236d)...Magnet body (magnet roller) 26A, 26B...Fixed support plate
27...Developer housing 276, 277, 278, 27
9...Bearing G27a~G
27d...Gear G28a-G28d...Gear
G29a~G29d...Gear

Claims (2)

[Claims] 1. An image forming means including an image bearing member that is rotatably held and on which an electrostatic latent image is formed, and a plurality of developing devices that develop the electrostatic latent image to form a color toner image. In a color image forming apparatus in which a unitized process cartridge is removably inserted into the apparatus main body, in each of the plurality of developing units, the central axis of a fixedly arranged magnet body having a plurality of magnetic poles and the inner a drive shaft of a rotatable developer carrier having the magnetic body and carrying developer on its surface; a drive shaft of a rotatable developer supplying member that supplies developer to the developer carrier; A fixed support plate that positions each shaft end of the drive shaft of a rotatable developer stirring member that supplies and stirs developer to the supply member is configured as a single piece common to each developer, and the fixed support plate is attached to the developer housing. A process cartridge for a color image forming device, which is fixed to the body. 2. The fixed support plate is formed in a shape that covers the outer periphery of a plurality of gears attached to shaft ends of drive shafts of each of the developing devices protruding outside the process cartridge,
and has a shape that protrudes downward from the bottom outer wall of the process cartridge, so that when the process cartridge is taken out of the main body of the color image forming apparatus and placed on a flat part, the outer diameter of the gear is protected. 2. A process cartridge for a color image forming apparatus according to claim 1.