JP3814378B2 - Electrophotographic image forming apparatus and developing cartridge - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention has a plurality of developing cartridges that are detachable from the apparatus main body, and the plurality of developing cartridges are sequentially switched by a rotary developing cartridge switching mechanism to switch the developing cartridges to be provided for development to form a multicolor image. The present invention relates to a forming apparatus and a developing cartridge.
[0002]
[Problems to be solved by the invention]
The present invention is a further development of the prior art described below.
[0003]
The present invention does not have a large hole on the side surface of the developing cartridge switching mechanism, and the developing cartridge switching mechanism as a whole has high rigidity, and the positioning of the developing cartridge is accurate, and a multi-color image with high holding rigidity of the developing device is formed. In addition to being an apparatus, the attitude of the developer cartridge can be changed depending on the position of the developer cartridge, and the developer cartridge is selectively used as the electrophotographic photosensitive member at a position facing the electrophotographic photosensitive drum. It is an object of the present invention to provide an electrophotographic image forming apparatus and a developing cartridge that can be positioned with respect to each other and can be appropriately arranged with an electrophotographic photosensitive drum and a developing cartridge switching mechanism.
[0004]
[Means for Solving the Problems]
Typical configurations of the present invention for achieving the above object, a plurality of developing cartridges, provided rotatably device body around an axis parallel with respect to the central axis of rotation of the electrophotographic photosensitive drum detachably mounted to the rotary type developing cartridge switching mechanism to rotate the developing cartridge switching mechanism, by switching the stop position, switches the developer cartridge that faces the electrophotographic photosensitive drum, a multicolor image In the electrophotographic image forming apparatus to be developed,
Having protruding rotation center member comprising a pivotable rotation center axis parallel to the center of said electrophotographic photosensitive drum at both ends, and the rotation center holding section member swingably supported in the developing cartridge,
The development in the center of the cartridge switching mechanism is provided to protrude to the radial direction, by oscillating the developing cartridge wherein the developer cartridge in a state in which the are attached to the developing cartridge switching mechanism is in contact with around the holding portion a cam portion for controlling the attitude of the developing cartridge,
And an elastic member biasing toward the developing cartridge to the cam portion,
A pressurizing mechanism provided at a central portion of the developing cartridge switching mechanism, wherein the developer carrying member provided on the developing cartridge pressurizes the developing cartridge at a position facing the electrophotographic photosensitive drum; A pressurizing mechanism for pressurizing the developer carrying member to the electrophotographic photosensitive drum;
An electrophotographic image forming apparatus comprising the developing cartridge switching mechanism having the above .
[0005]
Another configuration according to the present invention for achieving the above object, a plurality of developing cartridges are provided in the rotatable apparatus body around an axis parallel with respect to the central axis of rotation of the electrophotographic photosensitive drum and a rotary developing cartridge switching mechanism detachably is mounted, rotates the developing cartridge switching mechanism, by switching the stop position, switches the developer cartridge that faces the electrophotographic photosensitive drum, a multicolor image In an electrophotographic image forming apparatus for developing
The developing cartridge and the rotation center member said projecting becomes swingable in parallel to the center and the rotation center axis of the electrophotographic photosensitive drum at both ends in the switching mechanism, the posture deciding member from the rotation center member spaced radially When the a, a removably said rotation center member from a direction perpendicular to the rotational center member of the developing cartridge, and a holding portion supporting the rotational center member swingably,
Wherein the developing cartridge urges oscillated around the holding portion, and an elastic member biasing toward the developer carrying member provided in the developing cartridge in the center of the developing cartridge switching mechanism,
Said developing cartridge is provided at the center of the switching mechanism attitude decided member abuts the cylindrical portion of the developing cartridge to swing by the elastic member provided in the center and concentrically,
A pressure member provided at the cylindrical portion and provided so as to be movable outward in the radial direction of the cylindrical portion , wherein the tip cam is moved outward by the biasing member. surface pressurizes the cam surface the posture deciding member positioned outside the periphery of the cylindrical portion, against said developing cartridge to the elastic force of the elastic member around the said holding part swing a pressure member which pressurized the developer carrying member to said electrophotographic photosensitive drum and,
An electrophotographic image forming apparatus comprising:
[0016]
[Prior art]
2. Description of the Related Art Conventionally, in an electrophotographic image forming apparatus that forms a multicolor image, a plurality of developing devices are supported around a rotating member that rotates around a central axis, and latent images of each color on a photosensitive drum are developed by each developing device. is doing. In an apparatus using a rotating type developer switching mechanism that rotates such a developer around an axis parallel to the rotation center axis of the photosensitive drum, each developer is parallel to the rotation center axis of the developer switching mechanism. Is inserted from any direction.
[0017]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the following description, the longitudinal direction refers to the axial direction of a developing sleeve, a photosensitive drum, a carousel, or the like.
[0018]
FIG. 18 shows an overall view of the 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, and the latent image is a carousel 103 that is a rotary developing cartridge switching mechanism. Thus, development is performed by the development cartridge 104Y that is rotationally moved to the development position facing the image carrier 100. The developed image on the image carrier 100 is transferred onto the intermediate transfer belt 106 of the intermediate transfer unit 105 by the primary transfer unit 108. Here, the intermediate transfer belt 106 is driven by a drive roller 107 in the intermediate transfer body unit 105 by a drive source of the apparatus main body 114. The above-described latent image formation-latent image development-primary transfer process is repeated for each of the developing cartridges 104M, 104C, 104B, and a multicolor image is formed on the intermediate transfer belt 106. Next, the recording medium is fed from the paper feeding cassette 110, and the image on the intermediate transfer belt 106 is transferred onto the recording medium in the secondary transfer unit 109. 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 to which the image has been transferred is conveyed to the fixing unit 113 by the conveying unit 112, fixed by the fixing unit 113, and then discharged.
[0019]
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 that is a developer carrying member, a developing blade 411, a developer accommodating portion 408, a developer agitating 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 rocking center members 401 and 402 are provided at both ends of the developing cartridge 104 so as to protrude outward from the frame of the developing cartridge 104 in parallel with the developing sleeve 407. Further, when the developing cartridge 104 is in a single state, the vicinity of the developing sleeve 407 is covered with a shutter cover 405, and when mounted on the apparatus main body 114, the developing cartridge 104 is centered on the swing center members 401 and 402 held by the holding portions 312 and 313. On the other hand, after the shutter cover 405 is accommodated in the carousel 103, the cartridge frame 63 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 as shown in FIGS. , 402, and the developing cartridge 104 is urged clockwise. The cover 405 is opened. The cover 405 is fitted to the center of the swing center member 401, 402 and can be rotated about the same center as the swing center member 401, 402. Here, a drive connection member 410 that is engaged with and disengaged from a drive connection member (to be described later) of the apparatus main body 114 is provided at the center of one of the swing center members 401. Further, a contact portion 409 for applying a developing bias to the developing sleeve 407 from the high-voltage power supply of the apparatus main body 114 is provided on the end surface in the longitudinal direction of the cartridge frame of the developing cartridge 104 on substantially the same plane as the end surface.
[0020]
FIG. 5 shows an overall view of the carousel 103. The carousel 103 connects the side plates 301, 302 at the positions where the side plates 301, 302 are arranged equally in the circumferential direction, and the mounting side of each developing cartridge 104. It is composed of four stays 303 serving as partition walls, bearings 304 and 306 fixed to the main body stays 700 and 701 at the center of rotation, a center stay unit 309 and a bearing 304 fixed between the bearings 304 and 306, respectively. 306 and bearings 304 and 306 at the center of the center stay unit 309 and a center shaft 308 that fits into the center stay unit 309 are provided. Between the bearings 304 and 306 and the side plates 301 and 302, the bearing 304 is provided. , 306, bearing rings 301 a fixed to the side plates 301, 302 are fitted with inner rings. The outer ring is fitted to the 02a ball bearings 305 and 307 are provided. In addition, flags 310 (four locations) corresponding to the toner colors of the storage portions of the developing cartridges 104 are provided on the side surface of the side plate 301, and the photosensors 311 provided on the apparatus main body stay 700 are connected to the carousel 103. It is configured to be swayed by movement. The photo sensor 311 is a revolution sensor that detects the revolution position of the carousel 103.
[0021]
6 and 7 are views of the side surface of the developing cartridge 104 mounted on the side plate 301 and the driving side plate 302, respectively. Each developing cartridge 104 has its swinging center members 401 and 402 positioned and held by holding portions 312 and 313 of the side plates 301 and 302 so as to be rotatable. 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 engages with and disengages from the drive connecting member 410 of the developing cartridge 104 is provided and contacts 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.
[0022]
FIG. 8 shows the drive side plate 302 as viewed from the main body stay 701 side (outside). One end of the drive connecting member 314 is held by a holding member 315 fixed to the drive side plate 302, and the other end is held by a bearing 302c (see FIG. 9) integral with the drive side plate 302 so as to be movable in the longitudinal direction. ing.
[0023]
As shown in FIG. 9, the drive connecting member 314 has a gear 314b with a cap fitted to the other end of the shaft having a shaft coupling 314a at one end and fixed by a pin 314c. The gear 314b is meshed with a gear 318 supported by a rotation center bearing 306 of the carousel 103 via a ball bearing 306a via a gear 317 meshing with the gear 314b.
[0024]
9 and 10, the gear 318 supported by the rotation center bearing 306 that supports the carousel 103 is driven from the gear 324 of the developing motor 325 engaged with the gear 318 via the gears 319, 321, 322, and 323. Communicated. Here, the gear 319 is fixed to a shaft 320 that is rotatably supported by a bearing fixed to the main body stay 701. Therefore, 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, and rotates in one direction of the developing motor 325 (the direction A in FIG. )) Only. The gear 322 is a stepped gear, and a large gear 322 a and a small gear 322 b are integrally formed, and are rotatably supported by the main body stay 701. The large gear 322 a meshes with a gear 323 that is rotatably supported by the main body stay 701. The small gear 322b is engaged with the gear 321. The driving side plate 302 of the carousel 103 is provided with a gear 316 supported by a bearing 306 through a ball bearing 302a.
[0025]
A revolution motor 326 is fixed to the main body stay 701. The motor gear 327 fixed to the motor shaft of the revolving motor 326 is transmitted to the gear 316 via a gear 328 rotatably supported on a fixed shaft 701 a fixed to the main body stay 701, and the developing cartridge 104 of the carousel 103 is transmitted. Rotation switching operation (revolution) is performed.
[0026]
The developing drive connection release mechanism will be described with reference to FIG. The rotation of the developing motor 325 is transmitted to the gear 338 via the gear 330 that meshes with the large gear 322a of the gears 324, 323, and 322 and the small gear 322b of the gear 322. The gears 330 and 338 are rotatably supported by the main body stay 701. The gear 338 transmits the drive to the gear 331 on the shaft 339 via a shaft 339 fixed to the main body stay 701 and fixed to the gear 338, and the gear 331 and the shaft 339 are connected in one-way rotation. A one-way clutch is provided as a member, and the drive is transmitted only in the other direction of rotation of the developing motor 325 (the reverse of the A direction in FIG. 10). The drive is engaged with the gear 331 and is rotatably supported by the main body stay 701, and is engaged with the cam gear A332 via a cam gear A332 which is a gear integrally having a cam portion 334. The cam 340 is rotatably supported by the main body stay 701. It is transmitted to cam gear B333, which is a gear having one. Here, the cam gear B333 is formed with an end face cam 340 having a concave and convex shape in a direction perpendicular to the paper surface of FIG. 10 on the circumference, and the cam follower 337a at the tip of the lever unit 337 follows the cam 340 and the lever. The unit 337 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 in parallel with the plate surface of the flat plate-like main body stay 701. A plate cam 334 is also formed on the cam gear A 332, and a sensor lever 335 having a cam follower 335 a that follows the cam 334 on one end side is rotatably supported by a rotation center shaft 342 fixed to the main body stay 701. Rotating about the rotation center shaft 342 and biased clockwise in FIG. 10 by a spring (not shown). The light shielding member 335b on the other end side of the lever 335 shields the development sensor 336 using a photoelectric sensor fixed to the main body stay 701 when the development drive is connected, and does not shield the development sensor 336 when the development drive is released. The In the above description, the developing motor 325 and the revolution motor 326 are motors capable of controlling the rotation angle, for example, stepping motors.
[0027]
The developing drive connection releasing operation by the lever unit 337 will be described with reference to FIGS. A dog 337 b is provided at the other end of the lever unit 337 as an operating member for the drive connecting member 314.
[0028]
The drive coupling member 314 having the shaft coupling 314a is a shaft coupling 410a of the drive coupling member 410 provided at the center of the cylindrical center member 401 at the longitudinal end on the developing cartridge 104 side as shown in FIG. Is separated from the side plate 302 and the gear 314b by the spring force of the compression coil spring 343 inserted and contracted in the drive connecting member 314. When the lever unit 337 is operated in the development drive connection state and the entire carousel 103 is revolved in the direction of the arrow 345 in FIG. 11, the drive connection member 314 is pushed by the cam surface 337b1 of the dog 337b of the lever unit 337, and the shaft The shaft coupling 314a of the drive coupling member 314 moves in the direction against the spring force of the compression coil spring 343, and is coupled to the shaft coupling 410a at one end of the drive coupling member 410 rotatably supported by the developing cartridge 104. The carousel 103 stops in a state where the tip and the cap of the drive connecting member 314 are in contact. When the lever unit 337 is retracted in the direction of the arrow 353 after the development is completed, the drive connecting member 314 is retracted by the spring force of the compression coil spring 343 and the coupling of the shaft couplings 314a and 410a is released. It is also possible to connect the shaft couplings 314a and 410a by operating the lever unit 337 and moving the dog 337b in the direction of the arrow 353 shown in FIG.
[0029]
FIG. 13 shows a drive gear train in the developing cartridge 104. These drive gear trains are provided on one end side in the longitudinal direction of the developing cartridge 104 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 that meshes 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 that meshes with the developer agitating member 412 that rotates with the stepped gear 348 and meshes with the small gear 348b of the stepped gear 348 and transmits the drive to the gear 349 that is coaxial with the developer stirring member 412. Is done.
[0030]
Further, in the developing cartridges 104M, 104C, and 104Y except for the black developing cartridge 104B, the gear 346 fixed to the coating roller 403 and the small gear 410c of the drive connecting member 410 are engaged with each other.
[0031]
In the above, as shown in FIG. 13, the drive connecting member 410 receives the drive force clockwise as indicated by the arrow. Since the center of the image carrier 100 is above the extension of the straight line connecting the centers of the drive connecting member 410 and the developing sleeve 407 in FIG. 13, the developing sleeve 407 is in the same direction as the rotational direction of the drive connecting member 410. It rotates around the swing center members 401 and 402 and presses against the image carrier 100. This pressure contact force acts like a wedge.
[0032]
Next, the developing contact contact release mechanism will be described with reference to FIGS. 6, 10, 14 and 15. FIG. 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 to a shaft 422 fixed to the main body stay 701. A release member 423 is fitted to a shaft 422 provided at the center of the cam gear C420 so as to be movable in the axial direction, and a protruding cam follower 423a provided on the release member 423 is provided between the main body stay 701 and the contact pin 426 on the cam 421. The spring force of the contact spring (compression coil spring) 425 contracted by the contact is received through the flange 426a of the contact pin 426 and is operated according to the rotation of the cam gear C420. The developing bias is guided from the high voltage power source of the apparatus main body 114 to the contact 424 and applied to the contact pin 426 via the contact spring 425. The contact pin 426 is guided by a guide bush 427 fixed to the main body stay 701, and the release member 423 moves the contact position and the release position with respect to the developer cartridge switching mechanism side, that is, the carousel side contact 428. In the contact position, the contact pin 426 contacts the carousel side contact 428, and the contact 428 is fitted to the guide portion 302b of the driving side plate 302 of the carousel 103 via the contact spring 429 so as to be axially movable. The contact member 430 contacts the contact member 409 (see FIG. 4) on the developing cartridge 104 side, and the contact member 409 connects the developing cartridge 104 to the developing sleeve 407. Thus, the development contact contact 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 in this way, the contact life is greatly increased, and the developing cartridge 104 that is not left for development passes through the position of the image carrier 100 and the contact pin 426 carousel side contact Since 428 is non-contact, it is smoothly performed.
[0033]
Development drive connection release and development contact release control will be described with reference to FIGS. 16 and 17.
[0034]
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 an active signal is input from the development sensor 336 rotates the revolution motor 326 via a driver 351. 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. The CPU 350 has a prohibition circuit in the program for issuing a command for energizing only one of the drivers 351 and 352.
[0035]
In FIG. 17, when the carousel 103 enters the revolution operation, first, at step 600, it is confirmed whether the developing sensor 336 is on or off. 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 couplings 314a and 410a are not engaged even if the center lines coincide with each other. If the development sensor 336 is on in step 600, the process proceeds to step 603.
[0036]
If the development sensor 336 is off in step 601, the development motor 325 is rotated in the direction of arrow A. This rotation is transmitted to the gears 324, 323, 322, 321 and the shaft 320 with reference to FIG. 10, but provided between the gear 321 and the shaft 320 rotatably supported by the bearing 355 on the shaft 320 shown in FIG. The one-way clutch 329 causes the gear 321 to idle on the shaft 320 and the gear 319 to not rotate. Therefore, the drive connecting member 314 on the carousel 103 side does not rotate via the gears 319, 318, 317, and 314b. On the other hand, the rotation of the gear 322 is transmitted to the gears 330 and 338 and the shaft 339, and the gear 331 is rotated via the 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 around the shaft 342 in FIG. 10, raises the light shielding member 335b, and turns off the developing sensor 336. To turn on. At this time, the cam gear A 332 transmits the rotation to the cam gear B 333, and the cam gear B 333 and the cam 340 rotate, but the rotation angle is within the range of the lift 0, and the cam follower 337 a of the lever unit 337 is pushed so that the lever unit 337 moves the shaft 341. The dog 337b is separated from the drive connection member 314 on the carousel 103 side without being rocked against the spring force of the torsion coil spring 344 in the center.
[0037]
In step 602, after the developing sensor 336 is switched from OFF to ON, the developing motor 325 is rotated by a predetermined rotation angle in the same direction and stopped. With this predetermined rotation angle, the rotation of the stepped gear 322 is transmitted to the cam gear C420, and the end face cam 421 pushes the cam follower 423a at the cam top to resist the release member 423 and the contact pin 426 against the spring force of the contact spring 425. As shown in FIG. 15, the contact pin 426 and the carousel side contact 428 cannot contact each other.
[0038]
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 transmitted to the gears 327, 328, and 316 and rotates the carousel 103.
[0039]
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 337 b is separated from the drive connecting member 314. Further, since the carousel side contact 428 is separated from the apparatus main body 114 side contact pin 426, the carousel 103 rotates without being applied with resistance, and the developing sleeve 407 passes through the position facing the image carrier 100. However, even if the dog 337b remains at a position where it acts on the drive connecting member 314 as shown in FIG. 11, the cam surface 337b1 is inclined with respect to the advancing / retreating direction of the drive connecting member 314. The operation in such a manner is allowed. Then, the process proceeds to step 607, where the revolution motor 326 is rotated by a predetermined rotation angle based on the signal from the revolution sensor (photosensor) 311 and then stopped.
[0040]
When developing in step 604, the revolution motor 326 stops at a position facing the developing sleeve 407 and the image carrier 100, and the developing cartridge 104 does not move. In step 605, the developing motor 325 is rotated in the direction opposite to the arrow A direction, and the sensor lever 335 is rotated clockwise around the shaft 342 in FIG. The development motor 325 is stopped after a predetermined rotation angle rotation with reference to switching from ON to OFF. When the developing motor 325 rotates in the direction opposite to the arrow A having a predetermined rotation angle, the cam gear B333 rotates and the cam 340 pushes the cam follower 337a to twist the lever unit 337 against the spring force of the coil spring 344 so that the shaft 341 is centered. And the dog 337b moves forward against the spring force of the compression coil spring 343, and the dog 337b moves forward 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 are moved forward. Are connected. At the same time, the contact pin 426 that has been pulled in by the cam top of the end face cam 421 by the rotation transmitted from the gear 322 to the cam gear C 420 by the rotation of the developing motor 325 in the direction opposite to the arrow A of the predetermined rotation angle is the end face cam 421. Since the cam follower 423a can advance to the lift 0 position as shown in FIG. 14, the contact spring 425 moves forward by pushing the contact pin 426 and the release member 423 with spring force, and presses the contact pin 426 to the carousel side contact 428.
[0041]
When the developing motor 325 is rotated in the direction of arrow A in step 605 after the above operation, the rotation is transmitted to the gears 324, 323, 322, 321, the shaft 320, the gears 319, 318, 317, 314 b, and the drive connecting members 314, 410 are The developing sleeve 407 rotates. Development is performed here.
[0042]
When the development by the developing sleeve 407 is completed in step 606, the developing motor 325 rotates in the reverse direction to the direction of the arrow A, and the developing sensor 336 rotates by a predetermined rotation angle with reference to switching of the signal from on to off. Stop. As a result, the dog 337b of the lever unit 337 is separated from the drive connection member 314 of the carousel 103, and the drive connection member 314 is retracted from the drive connection member 410 of the developing cartridge 104 by the spring force of the compression coil spring 343, and the shaft couplings 314a, 314a, 314a, 410a is spaced apart. At the same time, the cam gear C420 is rotated and the end face cam 421 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 moves away from the carousel side contact 428.
[0043]
In step 607, the revolution motor 326 is rotated and stopped after a predetermined rotation angle rotation with reference to the signal of the revolution sensor 311, whereby the carousel 103 is indexed and rotated.
[0044]
According to this embodiment, in a state where the developing cartridge is stopped facing the image carrier, the rotation for developing the developing sleeve and the input of the driving force to the developing cartridge are performed by the developing cartridge switching mechanism with one motor. The drive connecting member can be engaged and disengaged. Furthermore, it is also possible to simultaneously perform contact / separation of the contact of the carousel with the high voltage power supply for development of the main body of the apparatus with the same motor. Since the developing sleeve 407 can pass in front of the image carrier 100 with the driving force connecting member 410 and the dog 337b, the contact pin 426 for applying the developing bias, and the carousel side contact 428 separated from each other, the developing cartridge 104 can be switched. Performed smoothly and quietly.
[0045]
When the carousel 103 rotates and the developing sleeve 407 of the developing cartridge 104 faces the photosensitive drum 100 in a state where the developing cartridge 104 is mounted on the carousel 103 as described above, the pressure member is used when the carousel 103 stops. Since 500 protrudes and the developing cartridge 104 is swung around the rocking center members 401 and 402 and the spacer roller provided in the developing sleeve 407 is pressed against the photosensitive drum 100, a predetermined developing gap is obtained. On the other hand, when the developing sleeve 407 passes through the position facing the photosensitive drum 100, the developing sleeve 407 has a receding surface 506b for determining the position of the posture determining boss 404, so that a sufficiently large gap is provided between the developing sleeve 407 and the photosensitive drum 100. Since the developing sleeve 407 can pass through the surface facing the photosensitive drum 100 in this state, the positional accuracy of the distance between the centers of the photosensitive drum 100 and the carousel 103 does not need to be particularly high. Therefore, the process cartridge is awarded and is suitable for an electrophotographic image forming apparatus.
[0046]
(Embodiment 1 of a pressurizing mechanism for pressurizing a developer carrying member to a photosensitive drum)
The second embodiment will be described with reference to FIGS. In FIG. 19, the drive of the developing motor 325 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, both ends of the center shaft 308 are rotatably held by the bearings 304 and 306 fixed to the main body stays 700 and 701. A pressurizing mechanism including a pressurizing member 500, pressurizing cams 501 and 502, and a pressurizing spring 503 is arranged at both ends in the longitudinal direction inside the center stay unit 309 fixed to the bearings 304 and 306 as shown in FIG. Provided on each side. 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 the arrow B shown in FIG. The center shaft 308 is inserted through a long hole 500 a provided in the pressure member 500 in the arrow B direction so that the center shaft 308 does not interfere with the pressure member 500. The pressurizing cams 501 and 502 are eccentric cams and are fitted to the intermediate square section of the center shaft 308. Both ends of a pressurizing spring 503 that is a tension coil spring wound so as to press almost half the circumference of the pressurizing cams 501 and 502 are locked to a spring hook 500b provided on the pressurizing member 500.
[0047]
When the center shaft 308 rotates, the pressure cams 501 and 502 are rotated according to the phase of the center shaft 308, and the spring force of the pressure spring 503 applied between the cams 501 and 502 and the pressure member 500 is used. The pressurizing member 500 is configured to be able to switch between the pressurized state shown in FIGS. 21 and 23 and the retracted state shown in FIGS. 20 and 24. Here, the developing cartridge 104 can swing about the swing center members 401 and 402 at both ends in a state of being mounted on the carousel 103, and the pressurizing member 500 can add both ends in the longitudinal direction. The pressure receiving part 63a is pressurized. 20 shows a separated state between the image carrier 100 and the developing sleeve 407, and FIG. 21 shows a pressed contact state. In this way, the swinging / separating operation described above in the first embodiment of the developing cartridge 104 is interlocked with the development drive connection release and the development contact contact release.
[0048]
Here, a retracting cam portion 506 is formed in 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 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 by the pressure spring 507 in the clockwise direction around the swing center members 401 and 402, the posture determining bosses 403 and 404 follow the cam portion 506, so that the developing cartridge 104 is not developed. In the (retracted state), as shown in FIG. 20, the developing cartridge 104 further swings in the direction of the arrow 508, and the developing sleeve 407 and the photosensitive drum 100 are separated from each other.
[0049]
(Embodiment 2 of a pressurizing mechanism for pressurizing the developer carrying member to the photosensitive drum)
The second embodiment is shown in FIGS. 25, 26, 27, 28, and 29. FIG. The bearing members 304 and 306 are provided with linear guides 304b and 306b over a diameter, and a pressure slide member 504 is movably fitted to the guides 304b and 306b. The front surface 504a of the pressure slide member 504 has an arc shape and is located on the same cylindrical surface as the cylindrical outer circumferences 304c and 306c of the bearing members 304 and 306 in the retracted position. A long hole 504 b provided in the pressure slide member 504 is fitted to the center shaft 308 so that the pressure slide member 504 does not protrude from the forward position, and one end side of the long hole 504 b is in contact with the center shaft 308. A pressure spring 505 of a compression coil spring is contracted between the rear end of the pressure slide member 504 and the spring seats 304d and 306d at the ends of the guides 304b and 306b. As shown in FIG. 29, the attitude determining boss 404 of the developing cartridge 104 is in contact with the outer peripheral surfaces of the outer peripheral surfaces 304c and 306c of the bearing members 304 and 306 in the non-developing position. Next, when it is in the vicinity of the developing position, the bosses 403 and 404 abut against the front surface 504 a of the slide member 504, and further, the carousel 103 rotates and the developing sleeve 407 of the developing cartridge 104 abuts against the photosensitive drum 100. In this state, the developing sleeve 407 receives a pressure force and presses against the image carrier 100 by the spring force of the pressure spring 505.
[0050]
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]
【The invention's effect】
As described above, the plurality of developing cartridges are detachably mounted on a rotating type developing cartridge switching mechanism provided in the apparatus main body so as to be rotatable around an axis parallel to the rotation center axis of the electrophotographic photosensitive drum. In the electrophotographic image forming apparatus for developing a multicolor image by rotating the developing cartridge switching mechanism and sequentially switching the stop position thereof, the developing cartridge facing the electrophotographic photosensitive drum is switched. A rotation center member that is attached to the developing cartridge switching mechanism from a right angle direction of the carrier and can swing in parallel with the rotation center axis of the electrophotographic photosensitive drum in the developing cartridge switching mechanism is provided at both ends thereof. Is positioned in 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 position of the developing cartridge is determined by urging a part of the developing cartridge against the outer peripheral cam portion of the member. . As a result, the attitude of the developing cartridge when mounted on the developing cartridge switching mechanism can be made variable according to the revolution operation of the developing cartridge switching mechanism, the space efficiency of arrangement and the like can be improved, and the apparatus can be miniaturized.
[0052]
Next, when the developing cartridge comes to the developing position facing the electrophotographic photosensitive drum on the cam member, a pressing member for positioning the developer carrying member on the electrophotographic photosensitive drum by pressing and swinging the developing cartridge is provided. By providing, it is possible to prevent the protrusion of the developing cartridge from the developing cartridge switching mechanism other than in the vicinity of the developing position, which is effective in reducing the size of the apparatus.
[0053]
Further, the cam shape of the cam member is formed so that the developer carrying member of the developing cartridge is separated from the electrophotographic photosensitive drum before and after the developing position of the developing cartridge facing the electrophotographic photosensitive drum, and By switching the electrophotographic photosensitive drum and the developing cartridge by selectively pressing and swinging the developing cartridge at the developing position to position the developer carrier relative to the electrophotographic photosensitive drum. The degree of freedom of arrangement of the mechanism is increased, which is effective for downsizing of the apparatus.
[Brief description of the drawings]
The drawings all show an embodiment of the present invention. FIG. 1 is a plan view of a developing cartridge.
FIG. 2 is a longitudinal sectional view of a developing cartridge.
FIG. 3 is a left side view of FIG. 1;
4 is a right side view of FIG. 1. FIG.
FIG. 5 is a longitudinal sectional view of the carousel viewed partially through.
FIG. 6 is a side view of one end side of the carousel viewed from the inside.
FIG. 7 is a side view of the other end of the carousel viewed from the inside.
FIG. 8 is a side view of a driving side of the carousel.
FIG. 9 is a plan view partially showing a drive system for driving the developing cartridge.
FIG. 10 is a side view of the apparatus main body for explaining the development drive connection release mechanism and the development contact contact release mechanism according to the first embodiment;
FIG. 11 is a plan view seen from the radial direction of the carousel showing the connection of the drive connection members of the drive connection release mechanism.
FIG. 12 is a plan view seen from the radial direction of the carousel showing the connection of the drive connection members of the development drive connection release mechanism.
FIG. 13 is a side view showing a gear train in the developing cartridge.
FIG. 14 is a radial sectional view of a carousel of a development contact contact release mechanism.
FIG. 15 is a plan view of a developing contact contact release mechanism.
FIG. 16 is a control block diagram of a development drive connection release mechanism.
FIG. 17 is a flowchart of a development drive connection release mechanism and a development contact contact release mechanism.
FIG. 18 is a longitudinal sectional view of an electrophotographic image forming apparatus.
FIG. 19 is a side view of the apparatus main body for explaining a development drive connection release mechanism and a development contact contact release mechanism.
20 is a longitudinal sectional view of the oscillating and pressing mechanism of the first embodiment. FIG.
FIG. 21 is a longitudinal sectional view of the oscillating pressure mechanism according to the first embodiment.
22 is a plan view of the main part of the swing pressure mechanism of FIG.
FIG. 23 is a side view of FIG. 22;
24 is a side view of FIG. 22. FIG.
FIG. 25 is a longitudinal sectional view including the axis of the center stay unit according to the first embodiment.
FIG. 26 is a cross-sectional view perpendicular to the axis of the bearing flange portion according to the second embodiment.
FIG. 27 is a cross-sectional view perpendicular to the axis of the bearing flange portion according to the second embodiment.
FIG. 28 is a cross-sectional view perpendicular to the axis for explaining the posture of the developing cartridge mounted on the carousel.
FIG. 29 is a cross-sectional view perpendicular to the axis for explaining the posture 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 support (elastic receiving part)
100: Image carrier (photosensitive drum)
DESCRIPTION OF SYMBOLS 101 ... Optical unit 102 ... Process cartridge 103 ... Carousel 104, 104Y, 104M, 104C, 104B ... Development cartridge 105 ... Intermediate transfer body unit 106 ... Intermediate transfer body belt 107 ... Drive roller 108 ... Primary transfer part 109 ... Secondary transfer Section 110 ... Feed cassette 111 ... Secondary transfer roller 112 ... Conveying section 113 ... Fixing unit 114 ... Main body 301 ... Side plate 301a ... Bearing house 302 ... Drive side plate 302a ... Bearing house 302b ... Guide section 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 ... Holding portion 313 ... Holding portion 314 ... Drive coupling 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 335b ... Light shielding member 336 ... Development sensor 337 ... Lever unit 337a ... Cam follower 337b ... Dog 337b1 ... Cam surface 338 ... Gear 339 ... Shaft 340 ... Cam 341 ... Axis 342 ... Axis 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 ... Oscillation center member 402 ... Oscillation center member 403 ... Coating roller 404 ... Position determining boss 405 ... Shutter cover 407 ... Developer sleeve 408 ... Developer container 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 ... Developer cartridge switching mechanism side contact 429 ... Contact spring 430 ... Slide contact member 500 ... Pressure Member 500b ... Spring 501 ... Pressure cam 501a ... Elongation hole 502 ... Pressure cam 502a ... Elongation hole 503 ... Pressure spring 506 ... Cam part 506a ... Cylindrical surface 506b ... Retraction surface 507 ... Pressure spring 508 ... Arrow 700 ... Main unit stay 701 ... Main unit stay 701a ... Fixed shaft

Claims (5)

A plurality of developing cartridges detachably mounted on the electrophotographic photosensitive drum rotation type developing cartridge switching mechanism provided in the rotatable apparatus body around an axis parallel with respect to the central axis of rotation of the developing cartridge the switching mechanism is rotated by switching the stop position, switches the developer cartridge that faces the electrophotographic photosensitive drum, the electrophotographic image forming apparatus for developing a multi-color image,
Having protruding rotation center member comprising a pivotable rotation center axis parallel to the center of said electrophotographic photosensitive drum at both ends, and the rotation center holding section member swingably supported in the developing cartridge,
The development in the center of the cartridge switching mechanism is provided to protrude to the radial direction, by oscillating the developing cartridge wherein the developer cartridge in a state in which the are attached to the developing cartridge switching mechanism is in contact with around the holding portion a cam portion for controlling the attitude of the developing cartridge,
And an elastic member biasing toward the developing cartridge to the cam portion,
A pressurizing mechanism provided at a central portion of the developing cartridge switching mechanism, wherein the developer carrying member provided on the developing cartridge pressurizes the developing cartridge at a position facing the electrophotographic photosensitive drum; A pressurizing mechanism for pressurizing the developer carrying member to the electrophotographic photosensitive drum;
An electrophotographic image forming apparatus comprising the developing cartridge switching mechanism having the above . Before asked arm portion, the cam surface having said developing cartridge and a part cylindrical surface centered on the center of the switching mechanism, retraction plane of a plane having a smaller radius than the radius of the cylindrical surface continuous with the cylindrical surface and a, when the developing cartridge switching mechanism is rotated to move the developer carrier said developer cartridge is swung by the developing cartridge to the retraction plane abuts the toward the center of the image cartridge switching mechanism The electrophotographic image forming apparatus according to claim 1. Claim 2 wherein the retraction surface, characterized in that it is disposed at a position where the developer carrier when the developer carrier is opposed to the electrophotographic photosensitive drum away from said electrophotographic photosensitive drum The electrophotographic image forming apparatus described in 1. The pressurizing mechanism and movable pressure member for pressing the developing cartridge, a moving mechanism for moving the pressure member, rotatable in the moving mechanism engages which coincides with the center in the developing cartridge switching mechanism a center shaft for driving the moving mechanism and,
An apparatus according to claim 1, characterized in that it comprises a power transmission device which is arranged to the center shaft from the driving source of the apparatus main body. A plurality of developing cartridges rotatably rotary type provided in the apparatus main body to the developing cartridge switching mechanism is detachably mounted around an axis parallel with respect to the central axis of rotation of the electrophotographic photosensitive drum, said developing cartridge the switching mechanism is rotated by switching the stop position, switches the developer cartridge that faces the electrophotographic photosensitive drum, the electrophotographic image forming apparatus for developing a multi-color image,
The developing cartridge and the rotation center member said projecting becomes swingable in parallel to the center and the rotation center axis of the electrophotographic photosensitive drum at both ends in the switching mechanism, the posture deciding member from the rotation center member spaced radially When the a, a removably said rotation center member from a direction perpendicular to the rotational center member of the developing cartridge, and a holding portion supporting the rotational center member swingably,
Wherein the developing cartridge urges oscillated around the holding portion, and an elastic member biasing toward the developer carrying member provided in the developing cartridge in the center of the developing cartridge switching mechanism,
Said developing cartridge is provided at the center of the switching mechanism attitude decided member abuts the cylindrical portion of the developing cartridge to swing by the elastic member provided in the center and concentrically,
A pressure member provided at the cylindrical portion and provided so as to be movable outward in the radial direction of the cylindrical portion , wherein the tip cam is moved outward by the biasing member. surface pressurizes the cam surface the posture deciding member positioned outside the periphery of the cylindrical portion, against said developing cartridge to the elastic force of the elastic member around the said holding part swing a pressure member which pressurized the developer carrying member to said electrophotographic photosensitive drum and,
An electrophotographic image forming apparatus comprising:

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