JPH1152716A - Electrophotographic image forming device and developing cartridge - Google Patents

Abstract

PROBLEM TO BE SOLVED: To accurately position developing cartridges by providing rotary center members which can be rocked in parallel with the center axis of the rotation of a photoreceptor drum, in both end parts and positioning both end parts in a developing cartridge switching mechanism. SOLUTION: In an optical unit 101, a latent image is formed on the image carrier (photoreceptor drum) 100 as a drum-like photoreceptor provided in a process cartridge 102. The latent image is developed by a developing cartridge 104Y rotationally moved to a developing position facing the image carrier 100, by the cull cell 103 of the rotary developing cartridge switching mechanism and development is repeated by respective developing cartridges 104M, 104C and 104B, to form a multicolor image on an intermediate transfer belt 106. At this time, a state where the developing cartridges 104 are stopped to face the image carrier 100, the rotation for developing of a developing sleeve and the engagement with/disengagement from the developing cartridges 104, of a drive connecting member in an input part for driving force are attained by the switching mechanism for the developing cartridges 104 with one motor.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention has a plurality of developing cartridges which are detachable from an apparatus main body, and switches the developing cartridges which are sequentially applied to development by a rotary developing cartridge switching mechanism. The present invention relates to an electrophotographic image forming apparatus for forming an image and a developing cartridge.

[0002]

The present invention is a further development of the prior art described below.

According to the present invention, there is provided an electronic device for forming a multicolor image having a high rigidity of the entire developing cartridge switching mechanism because there is no large hole on a side surface of the developing cartridge switching mechanism, a precise positioning of the developing cartridge, and a high holding rigidity of the developing device. It is a photographic image forming apparatus, and its posture can be changed according to the position where the developing cartridge has moved, and the developing cartridge can be selectively electrophotographed at a position facing the electrophotographic photosensitive drum. An object of the present invention is to provide an electrophotographic image forming apparatus and a developing cartridge which can be positioned with respect to a photoconductor and can appropriately arrange an electrophotographic photosensitive drum and a developing cartridge switching mechanism.

[0004]

According to a first aspect of the present invention, a plurality of developing cartridges are provided on an apparatus main body so as to be rotatable about an axis parallel to a rotation center axis of an electrophotographic photosensitive drum. The developing cartridge switching mechanism is detachably mounted on the rotary developing cartridge switching mechanism, and by rotating the developing cartridge switching mechanism and switching its stop position, the developing cartridge facing the electrophotographic photosensitive drum is switched to develop a multicolor image. In the electrophotographic image forming apparatus, the rotation center member of the developing cartridge having a protruding rotation center member that can swing at a center parallel to the rotation center axis of the electrophotographic photosensitive drum at both ends is swingably supported. The holding portion and the developing cartridge switching mechanism are provided so as to protrude radially at the center of the developing cartridge switching mechanism. A cam portion for controlling the attitude of the developing cartridge by swinging the developing cartridge around the holding portion by contacting the developing cartridge in the attached state, an elastic member for urging the developing cartridge toward the cam portion, An electrophotographic image forming apparatus comprising a developing cartridge switching mechanism having the following.

According to a second aspect of the present invention, a cam portion for controlling the attitude of the developing cartridge has a partially cylindrical surface centered on the center of a developing cartridge switching mechanism and a moving radius smaller than the radius of the cylindrical surface. When the developing cartridge switching mechanism rotates, the developing cartridge comes into contact with the retreating surface, and the developing cartridge swings, so that the developer carrying member of the developing cartridge is rotated. Move to the center side of the developing cartridge switching mechanism.

According to a third aspect of the present invention, the retreat surface is disposed at a position where the developer carrier is separated from the electrophotographic photosensitive member when the developer carrier of the developing cartridge faces the electrophotographic photosensitive drum. An electrophotographic image forming apparatus according to the second invention, characterized in that:

According to a fourth aspect of the present invention, a developing cartridge having a developer carrying member is pressurized at a position where the developer carrying member is opposed to an electrophotographic photosensitive drum at the center of the developing cartridge switching mechanism. The electrophotographic image forming apparatus according to the first aspect of the present invention, further comprising a pressing mechanism for pressing the developer carrier to the electrophotographic photosensitive drum.

According to a fifth aspect of the present invention, the pressing mechanism has a movable pressurizing member for pressing the developing cartridge, a moving mechanism for moving the pressurizing member, and a developing cartridge switching mechanism which coincides with the center thereof. A center shaft that is rotatable and engages with the moving mechanism to drive the moving mechanism; and a power transmission device disposed from a driving source of the image forming apparatus main body to the center shaft. An electrophotographic image forming apparatus according to the invention.

A sixth invention according to the present application is a rotary type developing cartridge switching mechanism provided in an apparatus main body such that a plurality of developing cartridges are rotatable about an axis parallel to a rotation center axis of an electrophotographic photosensitive drum. It is mounted detachably on the mechanism, rotates the developing cartridge switching mechanism,
By switching the stop position, the developing cartridge facing the electrophotographic photosensitive drum is switched, and in the electrophotographic image forming apparatus for developing a multicolor image, the electrophotographic photosensitive drum is rotated at both ends in the developing cartridge switching mechanism. A holding portion for swingably supporting the rotation center member of the developing cartridge having a protruding rotation center member capable of swinging at a center parallel to the center axis; and a projection protruding radially from a center portion of the developing cartridge switching mechanism. The developing cartridge switching mechanism is rotated at a position where the developer carrier of the developing cartridge mounted on the developing cartridge switching mechanism is opposed to the electrophotographic photosensitive drum and abuts on the developing cartridge to hold the developing cartridge. To expose the developer carrier to electrophotography A cam member that presses against the drum, an electrophotographic image forming apparatus characterized by having a.

According to a seventh aspect of the present invention, there is provided a rotary developing cartridge switching mechanism in which a plurality of developing cartridges are provided on an apparatus main body so as to be rotatable about an axis parallel to a rotation center axis of an electrophotographic photosensitive drum. It is mounted detachably on the mechanism, rotates the developing cartridge switching mechanism,
By switching the stop position, the developing cartridge facing the electrophotographic photosensitive drum is switched, and in the electrophotographic image forming apparatus for developing a multicolor image, the electrophotographic photosensitive drum is rotated at both ends in the developing cartridge switching mechanism. A rotation center member perpendicular to the rotation center member of the developing cartridge, the rotation center member including a protruding rotation center member capable of swinging about a center parallel to the center axis and a posture determining member radially separated from the rotation center member; And a holding portion for swingably supporting the rotation center member, and a developing cartridge is pivotally biased about the holding portion to attach the developer carrier toward the center of the developing cartridge switching mechanism. An elastic member for biasing, and provided at the center of the developing cartridge switching mechanism and provided concentrically with the center and oscillated by the elastic member. In a state in which the attitude determining member of the developing cartridge is in contact with the cylindrical portion and the cylindrical portion is provided so as to be movable outward in the radial direction of the cylindrical portion and is moved outward by the urging member. The cam surface at the tip is located outside the outer periphery of the cylindrical portion, and the cam surface presses the attitude determining member to swing the developing cartridge around the holding portion against the elasticity of the elastic member. And a pressure member for pressing the developer carrier to the electrophotographic photosensitive drum.

According to an eighth aspect of the present invention, there is provided a developing cartridge detachably mountable to an apparatus body of an electrophotographic image forming apparatus for forming a multicolor image, comprising: a developer carrier; and a developing cartridge frame for supporting the developer carrier. A rotation center member which is parallel to the developer carrier and protrudes from both ends of the development cartridge frame and is mounted on a development cartridge mounting portion of the apparatus main body and serves as a swing center, and is radially separated from the rotation center member. A position determining member provided to abut on the developing cartridge mounting portion of the apparatus main body; and an elasticity receiving portion receiving elasticity of an elastic member provided on the apparatus main body such that the position determining member comes into contact with the developing cartridge mounting portion. A developing cartridge characterized in that:

According to a ninth aspect of the present invention, there is provided an eighth aspect of the present invention, comprising a pressing force receiving portion of a pressing member provided in an apparatus body for pressing a developer carrier against an electrophotographic photosensitive drum. Of the developing cartridge.

According to a tenth aspect of the present invention, the developing cartridge has a developer accommodating portion for accommodating a developer, and a developer abutting member, which regulates a layer thickness of the developer and frictionally charges the developer. The developing cartridge according to the eighth or ninth aspect, further comprising a developing blade for applying a charge.

According to an eleventh aspect of the present invention, there is provided a developing cartridge according to the ninth aspect, further comprising an application member for abutting on the developer carrier and applying a developer to the developer carrier. is there.

A twelfth invention according to the present application is the developing cartridge according to the ninth invention, wherein the developer carrier is hollow and has a developing magnet at a central portion.

[0016]

2. Description of the Related Art Conventionally, in an electrophotographic image forming apparatus for forming a multicolor image, a plurality of developing units are carried around a rotating member which rotates around a central axis, and latent images of respective colors on a photosensitive drum are respectively provided. Developing with a developing unit. In an apparatus using a rotary developing device switching mechanism that rotates such a developing device around an axis parallel to the rotation center axis of the photosensitive drum,
Each developing device is inserted into the developing device switching mechanism from a direction parallel to the rotation center axis.

[0017]

Embodiments of the present invention will be described below with reference to the drawings. In the following description, the longitudinal direction refers to the axial direction of the developing sleeve, photosensitive drum, carousel, and the like.

FIG. 18 shows an overall view of an electrophotographic image forming apparatus. The optical unit 101 forms a latent image on an image carrier (photosensitive drum) 100 which is a drum-shaped photosensitive member provided in the process cartridge 102.
The development is performed by the developing cartridge 104 </ b> Y rotated to the developing position facing the image carrier 100 by the carousel 103 which is a rotary developing cartridge switching mechanism. The developed image on the image carrier 100 is transferred by the primary transfer unit 108 onto the intermediate transfer belt 106 of the intermediate transfer unit 105. Here, the intermediate transfer belt 106 is driven by a driving source of the apparatus main body 114 by a driving roller 107 in the intermediate transfer body unit 105. The above-described steps of latent image formation, latent image development, and primary transfer are subsequently repeated for each of the developing cartridges 104M, 104C, and 104B, and a multicolor image is formed on the intermediate transfer belt 106. Next, the recording medium is fed from the paper feed cassette 110, and the intermediate transfer belt 106 is
The upper image is transferred onto a recording medium. At this time, the secondary transfer roller 111 is brought into contact with the intermediate transfer belt 106 in accordance with the secondary transfer process. The recording medium on which the image has been transferred is conveyed to the fixing unit 113 by the conveying unit 112, and is discharged after being fixed by the fixing unit 113.

FIGS. 1 to 4 are explanatory views of the developing cartridge 104. FIG. The main body of the developing cartridge 104 includes a developing sleeve 407 as a developer carrier, a developing blade 411, a developer accommodating section 408, a developer stirring member 412, a coating roller 403 attached except for the black cartridge 104B, and the like. The sleeve 407, the developer stirring member 412, the application roller 403, and the like are driven by a drive source of the apparatus main body 114. Cylindrical swing center members 401 and 40 are provided at both ends of the developing cartridge 104.
2 is parallel to the developing sleeve 407 and the developing cartridge 10
4 is provided to protrude outward from the frame body. When the developing cartridge 104 is in a single state, the developing sleeve 407 is
When the vicinity is covered with the shutter cover 405 and mounted on the apparatus main body 114, the cartridge frame 63 rotates around the swing center members 401 and 402 held by the holding portions 312 and 313, while the carousel 1
After the shutter cover 405 is housed in 03, it is not rotated, and the developing sleeve 407 is opened. In this state, a spring receiver 63k provided on the cartridge frame 63 is pressed by a pressure spring 507 which is a compression coil spring provided on the side plates 301 and 302 of the carousel 103, and FIG.
As shown in FIG. 20, the developing cartridge 104 is urged clockwise about the swing center members 401 and 402. The cover 405 is opened. In addition,
The cover 405 is fitted to the center of the swing center members 401 and 402 and is rotatable about the same center as the swing center members 401 and 402. Here, a drive connection member 410 is provided at the center of the one swing center member 401 to be engaged and disengaged with a drive connection member described later of the apparatus main body 114. Also,
A contact portion 409 for applying a developing bias from a high-voltage power supply of the apparatus main body 114 to the developing sleeve 407 is provided on the longitudinal end surface of the cartridge frame of the developing cartridge 104 on substantially the same plane as the end surface.

FIG. 5 shows an overall view of the carousel 103. The carousel 103 connects the side plates 301 and 302 at positions where the side plates 301 and 302 are equally spaced in the circumferential direction, and connects the side plates 301 and 302 of the drive side to each other. 4 to be a partition
Bearings 304, 30 fixed to main body stays 700, 701 at the center of rotation.
6. A center stay unit 309 fixed between the bearings 304 and 306, and the bearings 304 and 306 and the bearings 304 and 3 at the center of the center stay unit 309.
06, a center shaft 308 fitted to the center stay unit 309, and bearings 304, 306.
And bearings 304, 302 between the side plates 301, 302, respectively.
An inner ring is fitted to 306, and an outer ring is fitted to bearing houses 301a, 302a fixed to the side plates 301, 302 to provide ball bearings 305, 307. On the side surface of the side plate 301, flags 310 (four places) corresponding to the toner colors of the storage portions of the respective developing cartridges 104 are provided, and the photo sensor 311 provided on the apparatus main body stay 700 is rotated by the rotation of the carousel 103. It is configured to pass through in motion. The photo sensor 311 is a revolution sensor that detects the revolution position of the carousel 103.

6 and 7 are views of the side plate 301 and the driving side plate 302 on the side where the developing cartridge 104 is mounted. In each developing cartridge 104, the swing center members 401, 402 correspond to the holding portions 3 of the side plates 301, 302.
Positioned and held rotatably at 12,313. Here, at the center of the holding portion 312 of the driving side plate 302, a drive connecting member 314 having a shaft coupling that is engaged with and disengaged from the drive connecting member 410 of the developing cartridge 104 is provided, and comes into contact with the contact portion 409 of the developing cartridge 104. A slide contact member 430 is provided on the side plate 302 on the center side of the holding portion 312.

FIG. 8 is a view of the driving side plate 302 viewed from the side of the main body stay 701 (outside). The drive connecting member 314 is a holding member 31 fixed to the drive side plate 302.
5, one end is held, and the other end is held by a bearing 302c (see FIG. 9) integrated with the driving side plate 302, and is movable in the longitudinal direction.

As shown in FIG. 9, this drive connecting member 314
A gear 314b with a cap is fitted to the other end of a shaft having a shaft coupling 314a at one end, and is fixed with a pin 314c. The gear 314b is the gear 31 that meshes with the gear 314b.
7 through the center of rotation bearing 306 of the carousel 103.
Gear 3 supported by a ball bearing 306a
18 is engaged.

9 and 10, a gear 318 of a developing motor 325 meshed with a gear 318 supported by a rotation center bearing 306 supporting the carousel 103 via gears 319, 321, 322, and 323. The drive is transmitted from. Here, the gear 319 is a shaft 32 rotatably supported by a bearing fixed to the main body stay 701.
It is fixed to 0. Thus, the gear 319 rotates integrally with the shaft 320, and a one-way clutch 329 is provided between the gear 321 and the shaft 320 to rotate the developing motor 325 in one direction (the direction A in FIG. )) Is transmitted to the shaft 320. The gear 322 is a stepped gear in which a large gear 322a and a small gear 322b are integrally formed, and is rotatably supported by a main body stay 701. The large gear 322a meshes with a gear 323 rotatably supported by the main body stay 701. And
The small gear 322b meshes with the gear 321. Also,
The driving side plate 302 of the carousel 103 is provided with a gear 316 which is supported at its center by a bearing 306 via a ball bearing 302a.

The main body stay 701 has a revolution motor 326.
Has been fixed. The motor gear 327 fixed to the motor shaft of the revolving motor 326 is a gear 3 rotatably supported by a fixed shaft 701a fixed to the main body stay 701.
The drive is transmitted to the gear 316 via 28, and the rotation switching operation (revolution) of the developing cartridge 104 of the carousel 103 is performed.

The developing drive connection release mechanism will be described with reference to FIG. The rotation of the developing motor 325 is controlled by the gear 32.
The gear 338 is transmitted via a gear 330 meshing with a large gear 322a of the 4,323,322 and a small gear 322b of the gear 322. The gears 330 and 338 are rotatably supported by the main body stay 701. The gear 338 is the gear 33
8 on a shaft 339 via a shaft 339 which is fixed and rotatably supported by the main body stay 701.
Is transmitted to the gear 331 and the shaft 339.
A one-way clutch is provided between them as a one-way rotation connecting member, and the drive is transmitted only by rotation of the developing motor 325 in the other direction (the reverse of the direction A in FIG. 10). The above-described driving is engaged with the gear 331 via a cam gear A332, which is a gear rotatably supported by the main body stay 701 and integrally having a cam portion 334, and is rotatably supported by the main body stay 701.
0 is transmitted to a cam gear B333, which is a gear integrally having 0. Here, the cam gear B333 has a circle on FIG.
And a cam follower 337a at the tip of the lever unit 337 follows the cam 340.
37 is fitted to the shaft 341 and rotates around the shaft 341.
A torsion coil spring 344 for pressing the cam follower 337a against the cam 340 is inserted into the shaft 341 and supported by the main body stay 701 in parallel with the plate surface of the flat main body stay 701. Further, the cam gear A332
Also, a plate cam 334 is formed, and a sensor lever 335 having a cam follower 335 a on one end side that follows the cam 334 is rotatably supported by a rotation center shaft 342 fixed to the main body stay 701, and the rotation center shaft 342. , And is urged clockwise in FIG. 10 by a spring (not shown). At the time of developing drive connection, a light shielding member 335b on the other end side of the lever 335 shields a developing sensor 336 using a photoelectric sensor fixed to the main body stay 701, and
When the development drive is canceled, the development sensor 336 is configured not to shield light. In the above description, the developing motor 32
5. As the revolution motor 326, a motor capable of controlling the rotation angle, for example, a stepping motor is adopted.

11 and 12, the lever unit 33 shown in FIG.
7 will be described. At the other end of the lever unit 337, a dog 337b is provided as an operating member for the drive connecting member 314.

Drive coupling member 31 having shaft coupling 314a
Numeral 4 denotes a shaft joint 410a of a drive connecting member 410 provided at the center of a cylindrical central member 401 at the longitudinal end on the side of the developing cartridge 104 as shown in FIG.
Means the drive connecting member 314 between the side plate 302 and the gear 314b.
Are separated by the spring force of the compression coil spring 343 inserted and contracted in FIG. When the lever unit 337 is operated in the developing drive connection state, the entire carousel 103 is moved as shown in FIG.
, The drive connecting member 314 is pushed by the cam surface 337b1 of the dog 337b of the lever unit 337 and moves in the axial direction against the spring force of the compression coil spring 343. 31
4 is a shaft coupling 41 at one end of a drive connecting member 410 rotatably supported by the developing cartridge 104.
0a and the leading end of the dog 337b and the drive connecting member 31
The carousel 103 stops with the cap of No. 4 in contact. After the development is completed, the lever unit 337 is moved to an arrow 3
When retracted in the direction of 53, the drive coupling member 314 is retracted by the spring force of the compression coil spring 343, and the shaft coupling 3
The connection between 14a and 410a is released. Note that, after the carousel 103 has stopped revolving first, the lever unit 337 can be operated to move the dog 337b in the direction of the arrow 353 shown in FIG. 12 to connect the shaft couplings 314a and 410a.

FIG. 13 shows a drive gear train in the developing cartridge 104. These drive gear trains are provided on one end side of the developing cartridge 104 in the longitudinal direction and are rotatably supported. The drive input to the drive connecting member 410 is transmitted to a gear 347 provided on the drive connecting member 410 and coaxially fixed to the developing sleeve 407 meshing with the large gear 410b, and a small gear 410c provided on the drive connecting member 410. Is transmitted to the large gear 348a of the stepped gear 348 which meshes with the gear 348, rotates the stepped gear 348, and transmits the drive to the gear 349 which is coaxial and integral with the developer stirring member 412 which meshes with the small gear 348b of the stepped gear 348. Is done.

The black developing cartridge 104B
Developing cartridges 104M, 104C, 104Y
In this case, the gear 346 fixed to the application roller 403 meshes with the small gear 410c of the drive connecting member 410.

In the above, as shown in FIG. 13, the drive connecting member 410 receives a driving force in the clockwise direction indicated by the arrow. The center of the image carrier 100 is the drive connecting member 41 in FIG.
0 and the developing sleeve 407 are located above an extension of a straight line connecting the centers of the developing sleeve 407 and the developing sleeve 407.
It rotates around 1402 and comes into pressure contact with the image carrier 100. This pressing force acts like a wedge.

Next, the mechanism for releasing contact of the developing contact will be described with reference to FIGS.
This will be described with reference to FIGS. 10, 14, and 15. A cam gear C420 is engaged with a cam gear A332 driven by the developing motor 325, and an end face cam portion 421 is formed on the cam gear C420. The cam gear C420 is rotatably fitted on a shaft 422 fixed to the main body stay 701. A shaft 42 provided at the center of the cam gear C420
A release member 423 is fitted on the release member 423 so as to be movable in the axial direction, and a projection-like cam follower 423a provided on the release member 423 has a contact spring (compression coil) contracted between the main body stay 701 and the contact pin 426 on the cam 421. The spring 425 receives the spring force of the spring 425 via the flange 426a of the contact pin 426 and is brought into contact with the spring 425, and operates according to the rotation of the cam gear C420. The developing bias is guided from the high-voltage power supply of the apparatus main body 114 to the contact 424, and is contacted via the contact spring 425 to the contact pin 42.
6 is applied. The contact pin 426 is connected to the main body stay 70.
The release member 423 is guided by the guide bush 427 fixed to 1 to move the contact position and the release position with respect to the developing cartridge switching mechanism side, that is, the carousel side contact 428. In the contact position, the contact pin 4
26 is in contact with the carousel contact 428 and the contact 42
8 is connected via a contact spring 429 to a slide contact member 430 that is axially movably fitted to the guide portion 302b of the driving side plate 302 of the carousel 103. The contact member 430 is a contact member 409 on the developing cartridge 104 side.
(See FIG. 4), and the contact member 409 connects the inside of the developing cartridge 104 to the developing sleeve 407. As a result, the development contact abutment release is performed in conjunction with the development drive connection release. Since the contact pin 426 and the carousel-side contact 428 do not slide as described above, the life of the contact is dramatically increased, and the developing cartridge 104 which is not subjected to development is not included.
Pass through the position of the image carrier 100, and the contact pin 426 is smoothly carried out because the carousel side contact 428 is not in contact.

With reference to FIGS. 16 and 17, a description will be given of the release drive connection release and development contact release control.

FIG. 16 is a control block diagram, and FIG. 17 is a flowchart for explaining the operation in FIG.
In FIG. 16, the central processing unit CPU 350 to which the active signal is input from the developing sensor 336
The revolution motor 326 is rotated via 51. The CPU 350 to which the active signal is input from the revolution sensor (photo sensor) 311 rotates the developing motor 325 via the driver 352. CPU 350 is driver 3
The program has a prohibition circuit for issuing an instruction to energize only one of 51 and 352.

In FIG. 17, when the carousel 103 starts revolving, first, at step 600, the developing sensor 3
Check ON / OFF of 36. When the developing sensor 336 is in the off state, the drive coupling members 314 and 410 are separated from each other in the circumferential direction, or the shaft coupling 314 even if their center lines are aligned.
a, 410a are not engaged. If the developing sensor 336 is ON in step 600, the process proceeds to step 603.

If the developing sensor 336 is off at step 601, the developing motor 325 is rotated in the direction of arrow A. This rotation is performed by referring to FIG.
A one-way clutch 329 provided between the shaft 320 and the gear 321 rotatably supported by the bearing 355 on the shaft 320 shown in FIG.
As a result, the gear 321 idles on the shaft 320, and the gear 319 is not rotated. Therefore, the gears 319, 318, 317, 3
Drive connection member 31 on the side of carousel 103 via 14b
4 does not rotate. On the other hand, the rotation of the gear 322 is transmitted to the gears 330 and 338 and the shaft 339, and rotates the gear 331 via a one-way clutch on the shaft 339. The gear 331 rotates the cam gear A332.
The cam 334 rotated with the rotation of the cam gear A332 pushes the cam follower 335a on the cam top side, rotates the sensor lever 335 counterclockwise about the shaft 342 in FIG. 10, raises the light shielding member 335b, and turns off the developing sensor 336. Turn on from. At this time, the cam gear A332 transmits the rotation to the cam gear B333, and the cam gear B333 and the cam 340 rotate, but the rotation angle is within the range of the lift 0, and the cam follower 3 of the lever unit 337 is rotated.
The dog 337b is separated from the drive connecting member 314 on the carousel 103 side without pressing the lever unit 337 to rotate the lever unit 337 around the shaft 341 against the spring force of the coil spring 344.

After the developing sensor 336 is switched from off to on in step 602, the developing motor 325 is rotated at a predetermined angle in the same direction and stopped. With this predetermined rotation angle, the rotation of the stepped gear 322 is controlled by the cam gear C42.
0, the end face cam 421 pushes the cam follower 423a with the cam top to release the release member 423, the contact pin 426.
Is retracted against the spring force of the contact spring 425, and the contact pin 426 and the carousel contact 428 cannot be brought into contact as shown in FIG.

In step 603, the rotation of the revolution motor 326 is started when the developing sensor 336 is turned on.
The rotation of the revolution motor 326 is performed by gears 327, 328, and 31.
Then, the carousel 103 is rotated.

In step 604, the developing cartridge 104 that does not perform development passes through a position facing the image carrier 100. At this time, the dog 337b is separated from the drive connecting member 314. The carousel side contact 428 is connected to the main body 1 of the apparatus.
Because it is far from the 14-side contact pin 426, the carousel 1
Numeral 03 denotes a developing sleeve 40 which rotates without adding resistance and rotates.
7 passes through a position facing the image carrier 100. However,
Even if the dog 337b is left at a position that acts on the drive connecting member 314 as shown in FIG. 11, such a configuration is possible because the cam surface 337b1 is inclined with respect to the direction in which the drive connecting member 314 advances and retreats. Is also acceptable. Then, the process proceeds to step 607, where the revolution motor 326 is stopped after rotating the revolution motor 326 by a predetermined rotation angle based on the signal of the revolution sensor (photo sensor) 311 as a reference.

When the development is performed in step 604, the revolving motor 326 stops at a position facing the development sleeve 407 and the image carrier 100, and the development cartridge 104 does not move. In step 605, the developing motor 325 is rotated in the direction opposite to the direction of arrow A, and the sensor lever 335 is rotated clockwise about the shaft 342 in FIG.
The developing motor 325 is stopped after a predetermined rotation angle rotation with reference to the switching of 36 from on to off. The rotation of the developing motor 325 in the direction opposite to the arrow A at a predetermined rotation angle rotates the cam gear B 333, and the cam 340 pushes the cam follower 337 a to twist the lever unit 337 to the axis 341 against the spring force of the coil spring 344. The dog 337b moves forward and the dog 337b advances the drive connecting member 314 on the carousel 103 side against the spring force of the compression coil spring 343, and the carousel-side shaft coupling 314a and the shaft coupling 410a of the developing cartridge 104. Concatenate. At the same time, rotation of the developing motor 325 in a direction opposite to the arrow A at a predetermined rotation angle causes the gear 322 to move from the cam gear C
With the rotation transmitted to 420, the contact pin 426 is retracted by the cam top of the end face cam 421.
Is the cam follower 42 to the position of lift 0 of the end cam 421.
Since 3a can proceed as shown in FIG. 14, the contact spring 425 pushes the contact pin 426 and the release member 423 by spring force to advance and press the contact pin 426 against the carousel contact 428.

After the above operation, when the developing motor 325 is rotated in the direction of arrow A in step 605, the gears 324, 3
23,322,321, shaft 320, gears 319,31
8, 317, 314b and the rotation is transmitted to the drive connecting member 3
14 and 410 rotate, and the developing sleeve 407 rotates.
Here, development is performed.

When the development by the developing sleeve 407 is completed in step 606, the developing motor 325 is rotated in the reverse direction to the arrow A.
The developing sensor 336 rotates at a predetermined rotation angle based on the switching of the signal from ON to OFF and stops. Thereby, the lever unit 337
Dog 337b is the drive connecting member 3 of the carousel 103.
14, the drive connecting member 314 is retracted from the drive connecting member 410 of the developing cartridge 104 by the spring force of the compression coil spring 343, and the shaft couplings 314a and 410a are separated. At the same time, the cam gear C420 is rotated and the end face cam 4
21 retracts the cam follower 323 and retracts the release member 423 against the spring force of the contact spring 425, so that the contact pin 426 separates from the carousel contact 428.

In step 607, the carousel 103 is indexed by rotating the revolution motor 326 and stopping it after a predetermined rotation angle rotation based on the signal of the revolution sensor 311 as a reference.

According to this embodiment, when the developing cartridge is stopped facing the image carrier, the developing cartridge is rotated by a single motor by the switching mechanism of the developing cartridge, and the developing sleeve is driven. The drive connection member of the force input unit can be disengaged. Further, the same motor can simultaneously make and break the contacts of the carousel and the contacts connected to the developing high-voltage power supply of the apparatus main body. Since the developing sleeve 407 can pass in front of the image carrier 100 in a state where the driving force connecting member 410, the dog 337b, the contact pin 426 for applying the developing bias, and the carousel contact 428 are separated from each other, the developing cartridge 1
04 is switched smoothly and quietly.

When the carousel 103 rotates and the developing sleeve 407 of the developing cartridge 104 faces the photosensitive drum 100 while the developing cartridge 104 is mounted on the carousel 103, the carousel 103 stops. The pressure member 500 projects and swings the developing cartridge 104 around the swing center members 401 and 402 so that the developing sleeve 407 is attached to the photosensitive drum 100.
A predetermined developing gap can be obtained because the spacer rollers provided in the above are pressed against each other. On the other hand, the developing sleeve 407 is
0, and has a receding surface 506b that determines the position of the attitude determining boss 404 when passing through the opposing position, so that the developing sleeve 407 is separated from the photosensitive drum with a sufficiently large gap between the developing sleeve 407 and the photosensitive drum 100. Drum 100
, It is not necessary to make the positional accuracy of the center-to-center distance between the photosensitive drum 100 and the carousel 103 particularly high. Therefore, the process cartridge is awarded and is suitable for an electrophotographic image forming apparatus.

(Embodiment 1 of Pressing Mechanism for Pressurizing Developer Carrier to Photoreceptor Drum) Embodiment 2 will be described with reference to FIGS. In FIG. 19, the developing motor 32
5 is transmitted to the cam gear A332. The cam gear A332 is fixed to the center shaft 308 provided at the center of the carousel 103, and is provided so as to be integrally rotatable. Here, the center shaft 308 is rotatably held at both ends thereof by the bearings 304, 306 fixed to the main body stays 700, 701. Bearing 3
Center stay unit 30 fixed to 04,306
9, inside the pressing member 500, the pressing cams 501 and 5
02, the pressing mechanism constituted by the pressing spring 503 is shown in FIG.
As shown in FIG. 5, they are respectively provided at both ends in the longitudinal direction. The pressing member 500 is fitted to a linear guide (not shown) of the center stay unit 309 so as to be movable in the direction of arrow B shown in FIG. The center shaft 308 is inserted through a long hole 500 a in the direction of arrow B provided in the pressing member 500, so that the center shaft 308 does not interfere with the pressing member 500. The pressure cams 501 and 502 are eccentric cams, and are fitted to the center shaft 308 having an intermediate rectangular cross section. Both ends of a pressure spring 503, which is a tension coil spring wound around the pressure cams 501 and 502 so as to press substantially half the circumference thereof, are locked to a spring hook 500b provided on the pressure member 500.

When the center shaft 308 rotates, the pressure cam 50 is moved according to the phase of the center shaft 308.
21 and 23 are rotated, and the pressing member 500 moves forward by the spring force of the pressing spring 503 applied between the cams 501 and 502 and the pressing member 500, and retreats from the pressed state shown in FIGS. 20 and 24 can be switched. Here, when the developing cartridge 104 is mounted on the carousel 103, the developing cartridge 104 can swing around the swing center members 401 and 402 at both ends. The pressure receiving portion 63a is pressurized. FIG. 20 shows a state in which the image carrier 100 and the developing sleeve 407 are separated from each other, and FIG. In this manner, the swinging and separating operation described above in the first embodiment of the developing cartridge 104, the development drive connection release, and the development contact contact release are linked.

Here, a retracting cam portion 506 is formed in each of the bearing members 304 and 306 corresponding to the developing position. The cam portion 506 has a cylindrical portion 506a and a receding surface 506b having a line whose moving radius from the center of the cylindrical portion 506a (= the center of the developing cartridge switching mechanism 103) is smaller than the radius of the cylindrical portion 506a. Since the developing cartridge 104 is urged clockwise around the swing center members 401 and 402 by the pressure spring 507,
When the attitude determining bosses 403 and 404 follow the cam portion 506, the developing cartridge 104 further swings in the direction of an arrow 508 during non-developing (retracted state) as shown in FIG. 407 and photosensitive drum 10
0 passes in a state of being separated.

(Second Embodiment of Pressing Mechanism for Pressurizing Developer Carrier to Photoconductor Drum) FIGS. 25, 26, 27, 28 and 29 show a second embodiment. The bearing member 30
4 and 306 are guides 304 that are linear across the diameter.
b, 306b are provided, and the pressure slide member 504 is movably fitted to the guides 304b, 306b. The front surface 504a of the pressure slide member 504 is arc-shaped and has a cylindrical outer periphery 304 of the bearing members 304 and 306 at the retracted position.
c and 306c are on the same cylindrical surface. An elongated hole 504 provided in the pressure slide member 504 in the center shaft 308 so that the pressure slide member 504 does not protrude from the advanced position.
b is fitted and one end of the elongated hole 504b is the center shaft 3
08. Spring seats 304d, 30 at the rear end of the pressure slide member 504 and the ends of the guides 304b, 306b.
A pressure spring 505 of a compression coil spring is contracted between the pressure spring 505 and 6d. Boss 4 for determining attitude of developing cartridge 104
In the non-development position, as shown in FIG. 29, the abutment 04 is in contact with the outer peripheral surfaces of the cylinders 304c and 306c of the bearing members 304 and 306. Next, when the bosses 403 and 404 come near the developing position, the slide members 504
, And the carousel 103 rotates, and the developing sleeve 40 of the developing cartridge 104 is rotated.
In a state in which the developing sleeve 7 is in contact with the photosensitive drum 100, the developing sleeve 407 receives a pressing force by the spring force of the pressing spring 505 and is in pressure contact with the image carrier 100.

According to the second embodiment, the developing sleeve can be pressed against the photosensitive drum only by the revolving operation of the carousel, and the attitude of the developing cartridge can be determined.

[0051]

As described above, the plurality of developing cartridges are rotatable developing cartridge switching mechanisms provided in the apparatus main body so as to be rotatable about an axis parallel to the rotation center axis of the electrophotographic photosensitive drum. In an electrophotographic image forming apparatus for developing a multi-color image, the developing cartridge switching mechanism is rotated, and the stop position is sequentially switched, thereby switching the developing cartridge facing the electrophotographic photosensitive drum and developing a multicolor image. The developing cartridge is mounted on the developing cartridge switching mechanism from a direction perpendicular to the developer carrier, and has rotation center members at both ends thereof which can swing in parallel with the rotation center axis of the electrophotographic photosensitive drum in the development cartridge switching mechanism. The two ends are positioned by the developing cartridge switching mechanism. Here, a cam member fixed to the apparatus main body is provided at the center of rotation of the developing cartridge switching mechanism, and a part of the developing cartridge is abutted against the outer peripheral cam portion of the cam member to determine the attitude of the developing cartridge. . Accordingly, the attitude of the developing cartridge when mounted on the developing cartridge switching mechanism can be changed according to the revolving operation of the developing cartridge switching mechanism, so that space efficiency such as arrangement can be increased, and the device can be downsized.

Then, when the developing cartridge comes to the developing position facing the electrophotographic photosensitive drum on the cam member, the developing cartridge is pressurized and swung to position the developer carrier on the electrophotographic photosensitive drum. By providing the pressure member, the protrusion of the developing cartridge from the developing cartridge switching mechanism other than in the vicinity of the developing position can be prevented, which is effective in reducing the size of the apparatus.

Further, before and after the developing position of the developing cartridge facing the electrophotographic photosensitive drum, the cam shape of the cam member is formed so that the developer carrier of the developing cartridge is separated from the electrophotographic photosensitive drum. ,And,
At the developing position, a pressurizing mechanism for selectively oscillating the developing cartridge under pressure to position the developer carrier with respect to the electrophotographic photosensitive drum is provided, thereby switching between the electrophotographic photosensitive drum and the developing cartridge. The degree of freedom of arrangement of the mechanism is increased, which is effective in reducing the size of the device.

[Brief description of the drawings]

 The drawings show embodiments of the present invention.

FIG. 1 is a plan view of a developing cartridge.

FIG. 2 is a vertical sectional view of a developing cartridge.

FIG. 3 is a left side view of FIG.

FIG. 4 is a right side view of FIG. 1;

FIG. 5 is a vertical cross-sectional view of the carousel as seen through partly.

FIG. 6 is a side view of one end of the carousel viewed from the inside.

FIG. 7 is a side view of the other end of the carousel as viewed from the inside.

FIG. 8 is a side view of the driving side of the carousel.

FIG. 9 is a plan view showing a drive system for driving the developing cartridge in a partial cross section.

FIG. 10 is a side view of the apparatus main body for explaining a developing drive connection releasing mechanism and a developing contact abutment releasing mechanism of the first embodiment.

FIG. 11 is a plan view showing the connection of the drive connection member of the drive connection release mechanism viewed from the radial direction of the carousel.

FIG. 12 is a plan view showing the connection of the drive connection member of the developing drive connection release mechanism viewed from the radial direction of the carousel.

FIG. 13 is a side view showing a gear train in the developing cartridge.

FIG. 14 is a radial cross-sectional view of the carousel of the developing contact abutment release mechanism.

FIG. 15 is a plan view of a developing contact abutment release mechanism.

FIG. 16 is a control block diagram of a developing drive connection release mechanism.

FIG. 17 is a flowchart of a developing drive connection releasing mechanism and a developing contact abutment releasing mechanism.

FIG. 18 is a longitudinal sectional view of the electrophotographic image forming apparatus.

FIG. 19 is a side view of the apparatus main body for explaining a developing drive connection releasing mechanism and a developing contact contact releasing mechanism.

FIG. 20 is a longitudinal sectional view of the swing pressure mechanism according to the first embodiment.

FIG. 21 is a longitudinal sectional view of the swinging pressure mechanism according to the first embodiment.

FIG. 22 is a plan view of a main part of the swing pressure mechanism of FIG. 20;

FIG. 23 is a side view of FIG. 22.

FIG. 24 is a side view of FIG. 22.

FIG. 25 is a longitudinal sectional view including the axis of the center stay unit of the first embodiment.

FIG. 26 shows the second embodiment and is a cross-sectional view perpendicular to the axis of the bearing flange portion.

FIG. 27 shows the second embodiment and is a cross-sectional view perpendicular to the axis of the bearing flange portion.

FIG. 28 is a cross-sectional view at right angles to the axis for explaining the attitude of the developing cartridge mounted on the carousel.

FIG. 29 is a cross-sectional view at right angles to the axis for explaining the attitude of the developing cartridge mounted on the carousel.

[Explanation of symbols]

C: Process cartridge Dy, Dm, Dc, Db: Developing cartridge 63: Cartridge frame 63k: Spring receiver (elastic receiving part) 100: Image carrier (photosensitive drum) 101: Optical unit 102: Process cartridge 103: Carousel 104, 104Y, 104M, 104C, 104B Developing cartridge 105 Intermediate transfer unit 106 Intermediate transfer belt 107 Driving roller 108 Primary transfer unit 109 Secondary transfer unit 110 Paper cassette 111 Secondary transfer roller 112 ... Conveying unit 113 ... Fixing unit 114 ... Device main body 301 ... Side plate 301a ... Bearing house 302 ... Drive side plate 302a ... Bearing house 302b
... Guide part 302c ... Bearing 303 ... Stay 304 ... Bearing 305 ... Ball bearing 306 ... Bearing 306a ... Ball bearing 307 ... Ball bearing 308 ... Center shaft 309 ... Center stay unit 310 ... Flag 311 ... Photo sensor (revolution sensor) 312 ... Hold Part 313: Holding part 314: Drive connecting member 314a: Shaft coupling 314b:
Gear 314c ... Pin 315 ... Holding member 316 ... Gear 317 ... Gear 318 ... Gear 319 ... Gear 320 ... Shaft 321 ... Gear 322 ... Stepped gear 322a ... Large gear 322b ... Small gear 323 ... Gear 324 ... Motor gear 325 ... Development motor 326: revolution motor 327: motor gear 328 ... gear 329: one-way clutch 330 ... gear 331 ... gear 332 ... cam gear A 333 ... cam gear B 334 ... cam 335 ... sensor lever 335a ... cam follower 3
35b: light shielding member 336: developing sensor 337: lever unit 337a: cam follower 3
37b ... dog 337b1 ... cam surface 338 ... gear 339 ... shaft 340 ... cam 341 ... shaft 342 ... shaft 343 ... compression coil spring 344 ... torsion coil spring 345 ... arrow 346 ... gear 347 ... gear 348 ... stepped gear 348a ... large gear 348b small gear 349 gear 350 central processing unit CPU 351 driver 352 driver 353 arrow 355 bearing 401 swing center member 402 swing center member 403 coating roller 404 posture boss 405 shutter Cover 407 Developing sleeve 408 Developer storage part 409 Contact member 410 Drive connecting member 410a Shaft coupling 410b
Large gear 410c Small gear 411 Developing blade 412 Developer stirring member 420 Cam gear C 421 End face cam 422 Shaft 423 Release member 423a Cam follower 425 Contact spring 426 Contact pin 426a Flange 427 Guide bush 428 Developing cartridge switching mechanism side contact 429 Contact spring 430 Sliding contact member 500 Pressing member 500b Spring hook 501 Pressing cam 501a Long hole 502 Pressure cam 502a Long hole 503 Pressure spring 506 Cam part 506a: Cylindrical surface 506b: Retracting surface 507: Pressure spring 508: Arrow 700: Main body stay 701: Main body stay 701a: Fixed shaft

Claims (12)

[Claims] A plurality of developing cartridges are detachably mounted on a rotary developing cartridge switching mechanism provided in an apparatus main body so as to be rotatable about an axis parallel to a rotation center axis of the electrophotographic photosensitive drum. By rotating the developing cartridge switching mechanism and switching its stop position, the developing cartridge opposed to the electrophotographic photosensitive drum is switched to develop a multicolor image. A holding portion that swingably supports the rotation center member of the developing cartridge having a protruding rotation center member that can swing at a center parallel to the rotation center axis of the body drum; and a center portion of the development cartridge switching mechanism. The developing cartridge, which is provided to project in the radial direction and is attached to the developing cartridge switching mechanism, abuts A developing cartridge switching mechanism having a cam portion for controlling the attitude of the developing cartridge by swinging the developing cartridge around the holding portion, and an elastic member for urging the developing cartridge toward the cam portion. An electrophotographic image forming apparatus, comprising: 2. A cam portion for controlling the attitude of the developing cartridge, wherein the cam portion has a part cylindrical surface centered on the center of the developing cartridge switching mechanism and a surface having a moving radius smaller than the radius of the cylindrical surface. The receding surface is the cam surface,
When the developing cartridge switching mechanism rotates, the developing cartridge comes into contact with the retreating surface, whereby the developing cartridge swings and the developer carrier of the developing cartridge moves toward the center of the developing cartridge switching mechanism. The electrophotographic image forming apparatus according to claim 1. 3. The method according to claim 2, wherein the retreating surface is provided at a position where the developer carrier is separated from the electrophotographic photosensitive member when the developer carrier of the developing cartridge faces the electrophotographic photosensitive drum. An electrophotographic image forming apparatus according to claim 2. 4. A developing cartridge having the developer carrying member is pressed at a position where the developer carrying member is opposed to the electrophotographic photosensitive drum at the center of the developing cartridge switching mechanism, and the developer carrying member is electrophotographed. 2. The apparatus according to claim 1, further comprising a pressing mechanism for pressing the photosensitive drum.
2. The electrophotographic image forming apparatus according to 1. 5. The pressure mechanism includes a movable pressure member that presses a developing cartridge, a moving mechanism that moves the pressure member, and a rotatable moving mechanism that coincides with the center of a developing cartridge switching mechanism. 5. The electrophotographic image according to claim 4, further comprising: a center shaft for driving the moving mechanism by engaging with the power transmission device disposed from a driving source of the image forming apparatus main body to the center shaft. 6. Forming equipment. 6. A plurality of developing cartridges are detachably mounted on a rotary developing cartridge switching mechanism provided in the apparatus main body so as to be rotatable around an axis parallel to a rotation center axis of the electrophotographic photosensitive drum. By rotating the developing cartridge switching mechanism and switching its stop position, an electrophotographic image forming apparatus for developing a multicolor image by switching the developing cartridge facing the electrophotographic photosensitive drum, A holding portion for swingably supporting the rotation center member of the developing cartridge having a protruding rotation center member that can swing at a center parallel to the rotation center axis of the electrophotographic photosensitive drum at both ends; and the development cartridge. Provided in the center of the switching mechanism so as to protrude in the radial direction At the position where the developer carrier of the mounted developing cartridge faces the electrophotographic photosensitive drum, the developing cartridge switching mechanism rotates to abut the developing cartridge and swing the developing cartridge about the holding portion to perform development. An electrophotographic image forming apparatus, comprising: a cam member for pressing the agent carrier against the electrophotographic photosensitive drum. 7. A plurality of developing cartridges are detachably mounted on a rotary developing cartridge switching mechanism provided in the apparatus main body so as to be rotatable about an axis parallel to a rotation center axis of the electrophotographic photosensitive drum. By rotating the developing cartridge switching mechanism and switching its stop position, an electrophotographic image forming apparatus for developing a multicolor image by switching the developing cartridge facing the electrophotographic photosensitive drum, The rotation center member of the developing cartridge having a protruding rotation center member that can swing at a center parallel to the rotation center axis of the electrophotographic photosensitive drum at both ends and an attitude determining member that is radially separated from the rotation center member. The rotation center member can be inserted and removed from the direction perpendicular to the axis, and the rotation center member is swingably supported. A holding portion, an elastic member for swingingly urging the developing cartridge around the holding portion to urge the developer carrier toward the center of the developing cartridge switching mechanism, and an elastic member provided at the center of the developing cartridge switching mechanism. A cylindrical portion provided concentrically with the center and in contact with an attitude determining member of the developing cartridge which swings by the elastic member, and provided on the cylindrical portion so as to be movable outward in a radial direction of the cylindrical portion. When the urging member moves outward, the tip cam surface is located outside the outer periphery of the cylindrical portion, and the cam surface presses the attitude determining member to center the developing cartridge around the holding portion. An electrophotographic image forming apparatus, comprising: a pressure member that oscillates against the elasticity of the elastic member to press the developer carrier against the electrophotographic photosensitive drum. 8. A developer cartridge detachably mountable to an apparatus body of an electrophotographic image forming apparatus for forming a multicolor image, a developer carrier, a developer cartridge frame supporting the developer carrier, and the developer carrier. A rotation center member which projects from both ends of the development cartridge frame in parallel with each other and is mounted on the development cartridge mounting portion of the apparatus main body and serves as a swing center; and a development cartridge of the apparatus main body provided radially away from the rotation center member. A developing cartridge comprising: an attitude determining member that abuts on a mounting portion; and an elastic receiving portion that receives an elastic force of an elastic member provided on the apparatus main body such that the attitude determining member abuts on the developing cartridge mounting portion. . 9. The developing cartridge according to claim 8, further comprising a pressing force receiving portion of a pressing member provided in an apparatus main body for pressing the developer carrying member against the electrophotographic photosensitive drum. 10. The developing cartridge has a developer accommodating portion for accommodating a developer, and a developing blade that abuts on the developer carrier to regulate a layer thickness of the developer and to apply a triboelectric charge to the developer. The developing cartridge according to claim 8, wherein: 11. The developing cartridge according to claim 9, further comprising an application member that abuts on the developer carrier to apply the developer to the developer carrier. 12. The developer carrier according to claim 9, wherein the developer carrier is hollow and has a developing magnet in the center.
4. The developing cartridge according to 1.