JP3073566B2 - Process cartridge and image forming apparatus - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a process cartridge having a plurality of developing means for developing a latent image formed on an electrophotographic photosensitive member, and an image forming apparatus provided with the process cartridge.

[0002]

2. Description of the Related Art In an image forming apparatus for forming a multiplex image on a transfer material by adopting a method in which a process cartridge including a plurality of developing means is attached to and detached from a main body, a plurality of cartridges are attached and detached. ON the connection of a plurality of driving force transmission paths connecting the developing means and the driving source on the main body side
It is necessary to provide a coupling mechanism for turning ON / OFF and a switching mechanism for selectively driving a plurality of developing units. The developing means includes a developing roller for applying a developer (toner) to the electrophotographic photosensitive member, and a container containing the developer.

[0003]

However, in the above-described conventional image forming apparatus, the connecting / disconnecting mechanism of the connecting mechanism when attaching / detaching the process cartridge must be manually operated, and the attaching / detaching operation of the process cartridge is troublesome. there were. Alternatively, if a method of connecting and disconnecting the coupling mechanism in conjunction with other operations when attaching and detaching the process cartridge is adopted, a mechanism for that purpose is required, resulting in an increase in cost.

Further, when another process cartridge independent of the above-mentioned process cartridge is similarly configured to be detachable from the apparatus main body, the same problem as described above occurs with respect to the drive force transmitting mechanism.

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and an object of the present invention is to eliminate the need for connecting / disconnecting a connecting mechanism at the time of attachment / detachment, thereby facilitating attachment / detachment operation, It is an object of the present invention to provide a process cartridge capable of realizing a cost reduction by simplifying a process cartridge and an image forming apparatus provided with the process cartridge.

[0006]

In order to achieve the above object, the present invention provides a process cartridge having an electrophotographic photosensitive member and a plurality of developing units, which is detachably mountable to an image forming apparatus main body. A first gear for transmitting a driving force from the image forming apparatus main body side to the photoconductor, and a first gear provided for each developing unit for transmitting the driving force to a developer supply unit provided for each developing unit. 2 gear, a cam provided between the first gear and the second gear, and coaxially provided with the first gear, and constantly meshed with the first gear, and by rotation of the cam, And a developing unit switching mechanism having a third gear that selectively meshes with one of the second gears.

Further, the present invention has an electrophotographic photosensitive member and a plurality of developing units, is configured to be detachable from an image forming apparatus main body, and transmits a driving force from the image forming apparatus main body to the photosensitive member. A first gear, a second gear provided in each developing unit for transmitting a driving force to a developer supply unit provided in each developing unit, the first gear and a second gear And a cam provided coaxially with the first gear and constantly meshing with the first gear, and selectively meshing with one of the second gears by rotation of the cam. A cartridge supporting member for detachably supporting a process cartridge having a developing unit switching mechanism having a third gear in an image forming apparatus main body; and the electronic copying machine having a process cartridge supported by the cartridge supporting member. A driving source for supplying a driving force to the photosensitive member; and a transfer unit for transferring a developer image formed on the electrophotographic photosensitive member of the process cartridge supported by the cartridge support member to a transfer material. It is characterized in that a forming device is constituted.

[0008]

According to the present invention, the third gear of the developing unit switching mechanism is prevented from meshing with the second gear of any of the developing units, except when the image is formed, so that the third gear of any of the developing units can be supplied to the developer supplying means of any of the developing units. If the driving force is not transmitted, it is not necessary to connect and disconnect the connecting mechanism each time when attaching and detaching the process cartridge as in the related art, and the attaching and detaching operation of the process cartridge is facilitated.

Further, since the developing unit switching mechanism composed of the cam and the third gear has both the function of transmitting the driving force to the developing unit and the function of selecting the developing unit, the switching mechanism conventionally provided independently is unnecessary. Thus, it is possible to simplify the configuration of the driving force transmission system, in other words, the process cartridge and the image forming apparatus, and to reduce the cost.

[0010]

Embodiments of the present invention will be described below with reference to the accompanying drawings.

FIG. 1 is a structural view of a main part of the image forming apparatus, FIGS. 2 and 3 are explanatory views of the operation of the driving force transmitting device, and FIG. 4 is a sectional view of the image forming apparatus.

The image forming apparatus according to the present embodiment is a printer that exposes a laser beam from a scanning optical unit B to an electrophotographic photosensitive drum A. In this printer, a cartridge 2 is attached to an apparatus main body 1. It is provided detachably. The cartridge 2 integrally supports the plurality of developing units 3, the photosensitive drum A, a charging roller C for uniformly charging the photosensitive drum A, a cleaning device D for cleaning and removing residual toner, and these members. And a frame E. The cartridge 2 is attached and detached along a support rail 20 shown in FIG.

On the other hand, a transfer drum F is disposed at a position facing the cartridge 2 in the apparatus main body 1, and the transfer drum F supports a transfer material supplied from a sheet cassette P and performs multiple transfer. The transfer material is supported during the process. Further, a corona discharger G for transfer is fixed inside the transfer drum F. The corona discharger G has a transfer bias for sequentially transferring the toner image formed on the photosensitive drum A to the transfer material. Is applied. After the transfer process is completed, the transfer material is separated from the transfer drum F and then sent to the heat fixing roller H, where the toner image is fixed, and finally discharged out of the apparatus main body 1 and discharged to the discharge tray I. Loaded on top.

The developing unit 3 includes a yellow toner developing unit 3a, a magenta toner developing unit 3b, and a cyan toner developing unit 3c.
The development unit 3d for black toner forms a full-color image by sequentially repeating the latent image formation, development, and transfer processes for each color.

As shown in FIGS. 1 to 3, the driving force is transmitted from a driving source 4 such as a motor provided on the apparatus main body 1 to a gear 6 on the apparatus main body 1 side via a belt 5. Further, it is transmitted to the gears 10 of the developing units 3 (3a, 3b, 3c, 3d) of the cartridge 2 via the gears 7, 8, 9 on the cartridge 2 side (see FIG. 2). Here, the gear 8 and the gear 9 are attached to the plate 11 and the plate 1
1 is rotatable about the axis of the gear 8, and is urged by a spring (not shown) in a direction in which the gear 9 meshes with the gear 10. The belt 5 and the gear 6 constitute a driving force transmitting mechanism on the apparatus main body 1 side, and the gear 7 constitutes a driving force transmitting means (first driving force transmitting means) for driving the photosensitive drum A. The gear 10 constitutes driving force transmitting means (second driving force transmitting means) for driving the developing unit 3.

On the other hand, the disc-shaped cam 1 is coaxial with the gear 7.
2 are provided, and a notch 12a is formed in the outer peripheral portion of the cam 12 as shown in the figure. The cam 12 and the gears 8 and 9 and the plate 11 are connected to the gear 7 and the gear 1.
A developing unit switching mechanism for turning on / off the connection to the unit 0 is configured.

When the cartridge 2 is attached or detached, the cams 12 are at the positions shown in FIG. 2. At this time, the ends of all the plates 11 are in contact with the outer peripheral portions of the cams 12 other than the notch 12a. Therefore, all the gears 9 are disengaged from the gear 10. Therefore, in this state, since the connection of the driving force transmission path connecting the developing unit 3 of the cartridge 2 and the driving source 4 of the apparatus main body 1 is released (OFF), the cartridge 2 can be easily connected to the apparatus main body 1. Can be detached. If the state shown in FIG. 2 is maintained except during image formation, it is not necessary to release the connection of the driving force transmission path each time the cartridge 2 is attached or detached.

On the other hand, the developing unit 3 is selectively driven as follows. That is, the cam 12 rotates as shown in FIG. 3, and the plate 11 engaged with the notch 12a of the cam 12 rotates about the axis of the gear 8 by the urging force of a spring (not shown).
, Only the gear 9 attached to the plate 11 meshes with the gear 10, and the developing unit 3 including the gear 10 is driven. Therefore, the developing unit switching mechanism composed of the gear 9, the plate 11, and the cam 12 also has a function of selecting the driving force to the developing unit 3, and as a result, the conventionally independent switching mechanism is unnecessary. As a result, the configuration of the driving force transmission device is simplified,
This can reduce the cost.

The cam 12 is rotationally driven by a driving source (not shown), and its driving is controlled in accordance with the state of attachment and detachment of the developing unit 3 and the cartridge 2 to be driven, and is stopped at a predetermined rotation stop position.

Next, a modified embodiment of the present invention will be described with reference to FIGS.
It will be described based on. FIG. 5 is a configuration diagram of a main part of the image forming apparatus, and FIGS. 6 to 9 are diagrams for explaining the operation of the driving force transmission mechanism. FIGS. 7A and 8A are front views of the cam and FIGS.
(B) and FIG. 8 (b) are views in the direction of arrow A in FIG. 6, FIG.
(A), (b) is a perspective view of FIG.7 (b), FIG.8 (b).

In this embodiment, the driving force is transmitted from a driving source 4 such as a motor or the like to a gear 6 on the apparatus main body 1 side via a belt 5 and further through gears 13 and 14 on the cartridge 2 side to the developing unit 3 side. Gear 10 is transmitted.

The gear 14 is pressed against the cam 15 by a spring 18 as shown in FIGS. 7 and 8, and the cam 15 rotates to form a recess 15a formed in the gear 15 as shown in FIG. 8B, the gear 14 engages with the concave portion 15a as shown in FIG. 8B, and the gear 14 moves by the urging force of the spring 18 to mesh with the gear 10.
The driving force is transmitted to the gear 10.

On the other hand, the concave portion 15a of the cam 15 is shown in FIG.
9 (a), the gear 14 does not engage with the concave portion 15a as shown in FIGS. 7 (b) and 9 (a), and the gear 14 releases the engagement with the gear 10. Is done.

Therefore, if all the gears 14 are kept apart from the gear 10 as shown in FIG. 6 except during the image formation, the mounting and dismounting operation of the cartridge 2 becomes easy simultaneously with the above embodiment.

Further, by selecting the transmission of the driving force to the developing unit 3 by rotating the cam 15, the simplification and cost reduction of the driving force transmitting device can be achieved in this embodiment as in the previous embodiment. Down is achieved.
The cam 15 receives a driving force from a driving source 17 shown in FIG.

In the above embodiment, the cartridge 2 has four developing units 3 (3a, 3b, 3c, 3c).
d), the photosensitive drum A, the transfer roller C, and the cleaning device D are integrally formed. However, since the black toner developing unit 3d is frequently used, the black toner developing unit 3d is used for the color toner. It is conceivable that the developing unit is configured separately from the developing units 3a to 3c.

An example in which the present invention is applied to a drive system employing such a configuration will be described below. In the drawings shown below, the same elements as those shown in the drawings of the above embodiment are denoted by the same reference numerals.

FIGS. 10 and 11 are longitudinal sectional views of the multicolor image forming apparatus. In the multicolor image forming apparatus, the main cartridge 2a and the sub cartridge 21
Are configured to be detachable.

The main cartridge 2a includes a photosensitive drum A, a corona discharger C, a cleaning unit D, and a plurality of developing units 3a for yellow, magenta, and cyan toners.
3b and 3c, and the sub cartridge 21 constitutes a single black toner developing unit.

A driving source 4 is provided in the apparatus main body 1, and the driving source 4 transmits a driving force to a gear 6 provided in the apparatus main body 1. The gear 6 is provided at the center of the main cartridge 2a where the photosensitive drum A is held.

The main cartridge 2a is provided with drive transmission gears 14 and 22. The gear 14 transmits power to a developing sleeve 23 as a developer carrier of the developing units 3a to 3c. Reference numeral 22 transmits power to the developing sleeve 24 of the sub cartridge 21. The gears 14 and 22 are provided with electromagnetic clutches (not shown), and the gears 14 and 22 selectively drive the developing sleeves 23 and 24 by turning on / off the respective electromagnetic clutches.

When the main cartridge 2a is mounted on the apparatus main body 1 as shown in FIG.
2 meshes with the gear 6, and the driving force is transmitted from the gear 6 to the gears 14 and 22. In this state, when the sub cartridge 21 is positioned in the direction of the arrow in FIG. 11 with respect to the main cartridge 2 a and the developing sleeve 24 is meshed with the gear 22, the developing sleeve 24 receives a driving force from the gear 22 and rotates. It can be driven.

As described above, in this embodiment, the driving force is transmitted to the sub cartridge 21 via the main cartridge 2a.
a, only the main cartridge 2 of the developing sleeve 24 of the sub-cartridge 21 needs to be positioned.
a, the positioning accuracy with respect to the photosensitive drum A is improved, the attachment / detachment mechanism of the sub-cartridge 21 is simplified, and the operability thereof is improved. The coupling mechanism is simplified.

The developing units 3a to 3c of the main cartridge 2a are provided with developer stirring members 26, which are intermittently driven to rotate by the driving force to stir the developer. The sub cartridge 21 is also provided with a developer stirring member 27, which is driven to rotate by receiving a driving force from the main cartridge 2a via a gear.

Next, FIGS. 12 and 13 show a modified embodiment. In this embodiment, the developer stirring member 27 of the sub-cartridge 21 receives the transmission of the driving force from the developing sleeve 25 via the gears 29 and 30. It is configured as follows. With such a configuration, drive connection can be performed simultaneously only by positioning the developing sleeve 24 of the sub cartridge 21 with respect to the photosensitive drum A of the main cartridge 2a.

FIGS. 14 and 15 show another embodiment.

In this embodiment, a gear 31 is provided at the center of the photosensitive drum A in the main cartridge 2a, and the gear 31 meshes with a drive gear 33 for driving the developing sleeve 23 of the developing units 3a to 3c. doing. The drive gear 33 is provided with an electromagnetic clutch (not shown), and the developing unit 3 is turned on / off by turning on / off each electromagnetic clutch.
a to 3c are selectively driven.

As shown in FIG. 15, the main cartridge 2a is positioned at the cartridge holding center 34 (see FIG.
4), the driving force of the drive source 4 is transmitted to the gear 31 on the main cartridge 2a side via the gear 6, and any one of the developing sleeves 23 is selectively driven.

On the other hand, a gear 35 is provided on the rotation shaft of the developing sleeve 24 of the sub-cartridge 21, and this gear 35 is also provided with an electromagnetic clutch (not shown). When the sub cartridge 21 is positioned with respect to the photosensitive drum A of the main cartridge 2a, the gear 35 meshes with the gear 31 of the main cartridge 2a, and the sub cartridge 21 can be driven.

Next, FIGS. 16 to 18 show still another embodiment of the present invention.

In this embodiment, the developing unit switching mechanism shown in FIG. 16 is provided in the main cartridge 2a. still,
17 (a) and 18 (a) are front views of the cam 36, and FIGS. 17 (b) and 18 (b) are bottom views of the developing unit switching mechanism (a view in the direction of arrow B in FIG. 16). .

The developing unit switching mechanism is provided with a cam 36 of the same type as shown in FIG. 9 which is driven to rotate about the central axis of the photosensitive drum A, and a part of the cam 36
6a are formed. When the switching gear 37 provided on the main cartridge 2a side is selectively engaged with the cam groove 36a, and the sub cartridge 21 is positioned with respect to the main cartridge 2a, FIGS. As shown in ()), the transmission gear 38 of the sub cartridge 21 is moved to a position where it can be connected to the switching gear 37. In this state, when the cam groove 36a is at the position shown in FIG. 17A, the switching gear 37 is not engaged with the cam groove 36a as shown in FIG. The transmission gear 38 of the cartridge 21 is kept disconnected from the transmission gear 38, and power is not transmitted to the transmission gear 38.
The sub cartridge 21 is not driven.

When the cam 36 is rotated by a drive source (not shown) and the cam groove 36a stops at the position shown in FIG. 18A, the switching gear 3 is turned on as shown in FIG.
7 engages with the cam groove 36a and meshes with the transmission gear 38, so that the driving force of the drive source 4 shown in FIG. 16 is transmitted to the transmission gear 38 via the coupling gear 6, gears 13 and 37, and The cartridge 21 is driven and used for development.

FIGS. 19 and 20 show another embodiment of the present invention.

In this embodiment, the switching gear 37 is provided on the side of the sub-cartridge 21 in the above-described embodiment, and as shown in FIG.
By selectively engaging with the cam groove 36a of the cam 36 provided on the side, the transmission gear 38 of the sub cartridge 21 is selectively meshed.

When the switching gear 37 is engaged with the transmission gear 38, the driving force of the drive source 4 shown in FIG. The sub cartridge 21 is driven by the transmission.

[0047]

As is apparent from the above description, according to the present invention, the third gear of the developing unit switching mechanism is prevented from engaging with the second gear of any developing unit except during image formation. If the driving force is not transmitted to the developer supply means of any of the developing units, it is not necessary to connect and disconnect the coupling mechanism each time when attaching and detaching the process cartridge as in the conventional case, and the attaching and detaching operation of the process cartridge can be performed. The effect of facilitation is obtained. Further, according to the present invention, the developing unit switching mechanism composed of the cam and the third gear has both the function of transmitting the driving force to the developing unit and the function of selecting the developing unit. This eliminates the need for a mechanism, and provides an effect that the configuration of the driving force transmission system, that is, the process cartridge and the image forming apparatus can be simplified and the cost can be reduced.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of a main part of an image forming apparatus according to the present invention.

FIG. 2 is an operation explanatory view of a driving force transmission device.

FIG. 3 is an explanatory diagram of an operation of the driving force transmission device.

FIG. 4 is a cross-sectional view of the image forming apparatus according to the present invention.

FIG. 5 is a configuration diagram of a main part of an image forming apparatus according to a modified embodiment.

FIG. 6 is an operation explanatory view of a driving force transmission device according to a modified embodiment.

7A is a front view of a cam, and FIG. 7B is an arrow A in FIG.
FIG.

8A is a front view of a cam, and FIG. 8B is an arrow view A in FIG.
FIG.

FIGS. 9A and 9B are perspective views of a cam.

FIG. 10 is a longitudinal sectional view of a multicolor image forming apparatus showing another embodiment of the present invention.

FIG. 11 is a longitudinal sectional view of a multicolor image forming apparatus showing another embodiment of the present invention.

FIG. 12 is a longitudinal sectional view of a multicolor image forming apparatus showing another embodiment of the present invention.

FIG. 13 is a longitudinal sectional view of a multicolor image forming apparatus showing another embodiment of the present invention.

FIG. 14 is a longitudinal sectional view of a multicolor image forming apparatus showing another embodiment of the present invention.

FIG. 15 is a longitudinal sectional view of a multicolor image forming apparatus showing another embodiment of the present invention.

FIG. 16 is a longitudinal sectional view of a multicolor image forming apparatus showing another embodiment of the present invention.

17A is a front view of the cam, and FIG. 17B is a bottom view of the developing unit switching mechanism (a view in the direction of arrow B in FIG. 16).

18A is a front view of the cam, and FIG. 18B is a bottom view of the developing unit switching mechanism (a view in the direction of arrow B in FIG. 16).

FIG. 19 is a longitudinal sectional view of a multicolor image forming apparatus showing another embodiment of the present invention.

FIG. 20 is a bottom view of the developing unit switching mechanism.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Image forming apparatus main body 2 Process cartridge 3 Developing unit (developing unit) 4 Drive source 7 Gear (first driving force transmitting unit) 8, 9 Gears (third driving force transmitting unit) 10 Gear (second driving force) Transmission means) 12 Cam (third driving force transmission means) 20 Support rail (Cartridge support member) A Electrophotographic photosensitive member F Transfer drum (Transfer means)

────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Masanori Yamagata 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc. (72) Inventor Hideki Tada 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Incorporated (72) Inventor Toshiki Nagase 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc. (56) References JP-A-57-136670 (JP, A) Jpn. Sho 62-25956 (JP) , U) (58) Fields investigated (Int. Cl. ⁷ , DB name) G03G 15/00 550 G03G 21/16-21/18 G03G 15/01 G03G 15/08

Claims (2)

(57) [Claims] 1. A process cartridge having an electrophotographic photoreceptor and a plurality of developing units and detachably mounted on an image forming apparatus main body, wherein a driving force from an image forming apparatus main body side is transmitted to the photoreceptor. A first gear, a second gear provided in each developing unit for transmitting a driving force to a developer supply unit provided in each developing unit, a first gear and a second gear Provided between the first
And a cam provided coaxially with the first gear, and always meshes with the first gear, and the rotation of the cam causes the first gear of the second gear to rotate.
And a developing unit switching mechanism having a third gear that selectively meshes with each other. 2. An image forming apparatus comprising: an electrophotographic photosensitive member;
A first gear for transmitting a driving force from the image forming apparatus main body side to the photoconductor, and a first gear provided for each developing unit for transmitting the driving force to a developer supply unit provided for each developing unit. 2 gear, a cam provided between the first gear and the second gear, and coaxially provided with the first gear, and constantly meshed with the first gear, and by rotation of the cam, A cartridge supporting member for detachably supporting a process cartridge provided with a developing unit switching mechanism having a third gear selectively meshing with one of the second gears in the image forming apparatus main body; A drive source for supplying a driving force to the electrophotographic photosensitive member of the process cartridge supported by the cartridge; and the electronic imaging of the process cartridge supported by the cartridge support member An image forming apparatus comprising a transfer unit that transfers the developer image formed on the photosensitive member to the transfer material, to be formed by providing a.