JP2000075619A - Developing cartridge and image forming device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a developing cartridge constituted so that the backlash of the supporting member of a shutter freely rotatably fitted in the fitting hole part of a cartridge frame is eliminated, an elastic member for biasing the supporting member can be fitted in a hole part without being warped and the shutter can be normally actuated. SOLUTION: Both ends of the cartridge frame 201Y are projectingly provided with the pipe-like hole part 205Y in which the tip 204Ya of the supporting member 204Y supporting the shutter of the developing cartridge is freely rotatably fitted. Besides, a receiving part 207Y obtained by dividing a pipe into half is fitted to the tip of the hole part 205Y. Then, the tip 204Ya engaged in the hole part 205Y is further received by the receiving part 207Y. Besides, a coil spring 206Y fitted to the outside surface of the hole part 205Y by being locked to the supporting member 204Y is also supported by the outside surface of the receiving part 207Y. Then, the spring 206Y is straightly fitted to the hole part 205Y.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to an image forming apparatus and a developing cartridge using an electrophotographic image forming method or the like.

[0002]

2. Description of the Related Art In an image forming apparatus such as a printer using an electrophotographic process, a photosensitive drum as an image carrier is uniformly charged, and a latent image is formed by selectively exposing the photosensitive drum. The image is recorded by developing the image with a developer toner to visualize it as a toner image, transferring the toner image to a recording medium, and fixing the transferred toner image to the recording medium by heat or pressure.

Such an image forming apparatus involves toner supply and maintenance of various process means. In order to facilitate the toner supply work and maintenance, the photosensitive drum, charging means, developing means, cleaning means and the like are framed. Cartridges have been put to practical use in the body.

[0004] Among such cartridges, a developing cartridge in which developing means is formed into a cartridge, when detached from the main body of the image forming apparatus, foreign matter enters a developing section provided with a developing roller for supplying toner to the photosensitive drum. In order to prevent toner from adhering to an external member, a shutter for opening and closing the developing unit is provided on a frame of the cartridge.

The shutter is rotatably mounted on the cartridge frame by support members fitted into mounting holes provided at both ends of the cartridge frame. Further, the shutter is urged in one rotational direction by an elastic member attached to the hole and the support member.

[0006]

However, in the above-described conventional developing cartridge, since the support member of the shutter is rotated about the mounting hole, there is a gap between the support member and the hole. Therefore, there is a problem that the support member fitted into the hole rattles and the shutter does not operate normally.

Further, when the elastic member is distortedly mounted in the mounting hole, it sometimes causes the shutter not to operate normally. To prevent this, it is necessary to increase the accuracy of the shutter components,
There was a disadvantage that the cost was high.

SUMMARY OF THE INVENTION It is an object of the present invention to eliminate rattling of a support member of a shutter rotatably fitted in a mounting hole of a cartridge frame, and to attach an elastic member for biasing the support member to the hole without distortion. It is an object of the present invention to provide a developing cartridge in which a shutter can be normally operated and an image forming apparatus provided with the developing cartridge.

[0009]

The above object is achieved by a developing cartridge and an image forming apparatus according to the present invention.
In summary, the present invention is a developing cartridge for developing an electrostatic latent image formed on an electrophotographic photoreceptor, which is detachable from an image forming apparatus main body, and has mounting holes at both ends of the cartridge frame. A developing member having the shutter rotatably provided in the cartridge frame by supporting a shutter covering the developing unit with a supporting member rotatably fitted in the hole, the supporting member fitted in the hole. And a receiving portion for further supporting the toner cartridge is provided to extend to the hole.

According to the present invention, a coil spring for urging the support member in one direction in the rotational direction is attached between the support member and the hole, and the coil spring is attached to the receiving portion so as to extend. Further, the hole portion is formed of a pipe-shaped member projecting from both ends of the cartridge frame, the receiving portion is formed of a member obtained by halving the same pipe member, and the coil spring is formed of the pipe-shaped member and the halved shape. Attached to the outer surface of the member, one end of the coil spring is engaged with the support member.

According to the present invention, there is provided an image forming apparatus provided with an electrophotographic photosensitive member on which an electrostatic latent image is formed, and a developing unit for developing the electrostatic latent image, wherein the developing unit is any one of the above-mentioned units. An image forming apparatus formed on a developing cartridge.

[0012]

Embodiments of the present invention will be described below in more detail with reference to the drawings.

FIG. 1 is a block diagram showing an embodiment of an image forming apparatus according to the present invention. This embodiment shows a multicolor laser beam printer.

As shown in FIG. 1, the image forming apparatus includes a drum-shaped electrophotographic photosensitive member, that is, a photosensitive drum 15 as an image carrier, around which a charging roller 17 and a fixed black developing cartridge 21B are provided. A rotatable color developing cartridge of three colors, that is, a yellow developing cartridge 20Y, a magenta developing cartridge 20M, a cyan developing cartridge 20C, an intermediate transfer drum 9, and a cleaning device 16 are arranged, and a scanner unit 30 is arranged above. I have.

The photosensitive drum 15 is a photosensitive drum unit 13
Is configured. The photosensitive drum unit 13 integrally combines the photosensitive drum 15, the charging roller 17, and the container 14 of the cleaning device 16 which also serves as a holder thereof, and is detachably mounted on the image forming apparatus main body. Have been.

In order to form an image, the photosensitive drum 15 is rotated in the direction of the arrow, the surface of the photosensitive drum 15 is uniformly charged by the charging roller 17, and image exposure from the scanner unit 30 is performed. To form an electrostatic latent image on the surface of the substrate.

In the scanner section 30, when an image signal is given, a laser diode emits image light corresponding to the image signal and irradiates the polygon mirror 31. The polygon mirror 31 is rotated at a high speed by a scanner motor to convert the image light. The light is reflected to selectively expose the surface of the rotating photosensitive drum 15 via the imaging lens 32 and the reflecting mirror 33,
An electrostatic latent image is formed on the surface of the photosensitive drum 15.

The latent image formed on the photosensitive drum 15 is provided with a developing cartridge 21B, 20Y, 20
Develop with M or 20C and visualize as a toner image. The obtained toner image is transferred to the surface of the intermediate transfer drum 9 by applying a transfer bias to the intermediate transfer drum 9 (primary transfer).

The above process is performed for four colors of yellow, magenta, cyan, and black, and the intermediate transfer drum 9
A color image is formed by superimposing four color toner images on the surface of. This color image is collectively transferred to the transfer material 2 which is a recording medium supplied to the intermediate transfer drum 9 (secondary transfer).

The transfer material 2 is stored in a paper feed cassette 1 and is taken out by paper feed rollers 3 and 4 and a retard roller 5 for preventing double feed, and is fed by a paper feed guide 6 and a transport roller 7.
Is transported to the registration roller 8 through the
Is supplied to the intermediate transfer drum 9 at a predetermined timing. At the same time, the secondary transfer roller 10 to which the transfer bias is applied contacts the intermediate transfer drum 9 with the transfer material 2 interposed therebetween, and the color image on the intermediate transfer drum 9 is secondarily transferred to the transfer material 2.

The transfer material 2 on which the color image has been transferred is conveyed to a fixing device 25 and fixed. The fixing device 25 has a fixing roller 26 and a pressure roller 27 pressed against the fixing roller 26, and these rollers 26, 27 have heaters 28, 29 built therein, respectively. The transferred transfer material 2 is fixed to a fixing roller 26.
Then, the toner is heated and pressed by the pressure roller 27 to fix the toner, thereby mixing the four colors of toner and fixing the toner to the transfer material 2, thereby forming a full-color permanent image. The transfer material 2 on which the fixing has been completed is discharged to a discharge portion 37 on the upper surface of the apparatus by discharge rollers 34, 35, and 36.

Now, the fixed black developing cartridge 21B
As shown in FIG. 3, is mounted at a fixed position obliquely above the photosensitive drum 15 with respect to the image forming apparatus main body, and is detachably installed in the axial direction of the photosensitive drum. , Developing roller 21 of developing cartridge 21B
The BS faces the photosensitive drum 15 with a predetermined minute gap.

The developing cartridge 21B includes a developing roller 2
After regulating the layer thickness of the black toner carried on 1BS by the regulating blade 21BB, the developing roller 21BS is rotated to convey the layer to a developing area facing the photosensitive drum 15, and develops the latent image on the photosensitive drum 15 to develop the black toner. To form an image.

Rotary yellow developing cartridge 20
As shown in FIG. 3, the Y, magenta developing cartridge 20M, and cyan developing cartridge 20C are detachably attached to a rotary 23 that rotates around a central axis 22 in the axial direction of the photosensitive drum, that is, attached to and detached from the image forming apparatus main body. It is installed freely. Developing cartridges 20Y to 20C
Of the photosensitive drum 15 with the rotation of the rotary 23
The developing roller is sequentially conveyed to a developing position opposed to the photosensitive drum 15, and is positioned at the developing position so as to face the photosensitive drum 15 with a predetermined minute gap.

The color developing cartridges 20Y to 20C will be further described. Since these are all configured in the same manner, the description will be made by taking the yellow developing cartridge 20Y as an example. The yellow developing cartridge 20Y is
As shown in FIG. 1, a developing roller 20YS, a regulating blade 20YB, and a coating roller 20YR are provided in a cartridge frame.

As shown in FIG. 2, the cartridge frame 201Y is provided with a plurality of positioning pins 204 for positioning the cartridge 20Y with respect to the rotary 23, and the shafts at both ends of the developing roller 20YS are connected to the developing roller 20YS. A spacer roller 202 for providing a predetermined gap with the photosensitive drum 15 is attached.

As shown in FIG. 4, the developing cartridge 20Y is provided with a shutter 203Y. When the developing cartridge 20Y is detached from the image forming apparatus main body, as shown in FIG. , And the developing unit.

As shown in FIG. 4, the support member 204Y of the shutter 203Y is provided on the cartridge frame 201Y.
And a sub-arm 210Y as an auxiliary regulating member are pivotally mounted. The upper end of the shutter 203Y is rotatably mounted on the support member 204Y, and the lower end of the shutter 203Y is rotatably mounted on the sub-arm 210Y. It is swingably supported along the outer surface. At the time of mounting, as the developing cartridge 20Y is inserted into the image forming apparatus main body, the shutter 203Y gradually moves upward as shown by a solid line in the figure to completely open, exposing the developing unit.

The support member 204Y has a U-shaped outer shape as shown in FIG.
4Ya is fitted into a pipe-shaped mounting hole 205Y protruding from the cartridge frame 201Y, and is rotatably mounted. As shown in FIG. 6, a coil spring 206Y attached to the outer surface of the hole 205Y is provided.
Is fixed to the support member 204Y, whereby the support member 204Y is urged downward.

The support member 204Y is provided with a
Since Ya is rotatably supported by the mounting hole 205Y, there is a gap between the distal end 204Ya and the inner wall of the hole 205Y. For this reason, conventionally, as shown in FIG. 7, there is a problem that rattling occurs between the front end portion 204Ya and the hole portion 205Y, and as a result, the shutter 203Y does not operate normally. Further, when attaching the coil spring 206Y to the outer surface of the hole 205Y, as shown in FIG.
When the coil spring 206Y is attached in a distorted state,
This also caused the shutter 203Y not to operate normally.

Therefore, in the present invention, as shown in FIG.
An extended receiving portion 207Y is provided at the end of the pipe-shaped hole portion 205Y, and as shown in FIG. 10, the supporting member distal end portion 204Ya fitted into the hole portion 205Y is further received by the receiving portion 207Y. Thus, the tip portion 204Ya was firmly supported. Also, as shown in FIG.
Receiving portion 207 for coil spring 206Y attached to the outer surface of
The coil spring 206Y is also supported on the outer surface of the
It was mounted straight on 5Y.

Accordingly, the support member 204Y is connected to the hole 205Y.
The shutter 203Y supported by the support member 204 can be attached to the shutter 203Y without rattling.
Can operate normally.

In the above, the developing cartridge used for the process cartridge type image forming apparatus has been described as an example. However, the present invention is not limited to this, and the developing means of the image forming apparatus not employing the process cartridge type is used. It is also possible to apply the present invention to the above. Although the image forming apparatus has been described using a laser beam printer as an example, the present invention can be applied to an image forming apparatus such as a copying machine, a facsimile machine, or a word processor.

[0034]

As described above, according to the present invention,
Attach the support member of the shutter that covers the developing section of the developing cartridge.Extend the receiving part that halves the pipe into the pipe-shaped mounting holes at both ends of the cartridge frame, and freely fit into the holes. The combined supporting member is further supported by the receiving portion, and the supporting member attached to the outer surface of the hole is also supported by the receiving portion of the coil spring that urges the supporting member in one direction of the rotation direction, so that the rattling of the supporting member is eliminated, Also, you can attach the coil spring to the hole without distortion,
As a result, the shutter can operate normally, and the performance of the shutter improves.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram showing one embodiment of an image forming apparatus of the present invention.

FIG. 2 is a perspective view illustrating an appearance of a developing cartridge installed in the image forming apparatus of FIG.

FIG. 3 is a sectional view showing a positional relationship of a developing cartridge in the image forming apparatus of FIG.

FIG. 4 is a side view of the developing cartridge of FIG. 2;

FIG. 5 is a perspective view showing one end of a conventional developing cartridge.

FIG. 6 is a perspective view showing the attachment of a coil spring attached to one end of a conventional developing cartridge.

FIG. 7 is an explanatory view showing rattling of a support member supporting a shutter in a conventional developing cartridge with respect to a mounting hole of a cartridge frame.

FIG. 8 is an explanatory view showing a state where the coil spring is distortedly attached in the attachment of FIG. 6;

FIG. 9 is a perspective view showing one end of the developing cartridge of FIG. 2;

10 is an explanatory view showing that there is no backlash in a mounting hole of a cartridge frame of a support member supporting a shutter in the developing cartridge of FIG. 2;

FIG. 11 is an explanatory diagram showing attachment of a coil spring attached to one end of the developing cartridge of FIG. 2;

[Explanation of symbols]

 15 Photosensitive drum 20Y to 20C Color developing cartridge 201Y Cartridge frame 202Y Developing roller 203Y Shutter 204Y Support member 204Y Tip end 205Y Mounting hole 206Y Coil spring 207Y Receiver

 ────────────────────────────────────────────────── ─── Continued on the front page (72) Inventor Nobuharu Hoshi 3-30-2 Shimomaruko, Ota-ku, Tokyo F-term in Canon Inc. (reference) 2H077 AA02 AC04 AD06 AD13 BA07 BA08 EA16 FA21 GA12

Claims (4)

[Claims] A developing cartridge for developing an electrostatic latent image formed on an electrophotographic photoreceptor, the developing cartridge being detachable from an image forming apparatus main body, and having mounting holes at both ends of the cartridge frame; By supporting a shutter that covers the developing unit with a supporting member rotatably fitted in the hole, the developing cartridge having the shutter openably and closably provided in the cartridge frame further supports the supporting member fitted in the hole. And a receiving portion extending from the hole portion. 2. The developing device according to claim 1, wherein a coil spring for urging the support member in one direction of rotation is attached between the support member and the hole, and the coil spring is attached to the receiving portion so as to extend. cartridge. 3. The cartridge according to claim 1, wherein the hole is formed of a pipe-shaped member protruding from both ends of the cartridge frame, the receiving portion is formed of a member obtained by dividing the same pipe member in half, and the coil spring is formed of the pipe-shaped member and 3. The developing cartridge according to claim 2, wherein the cartridge is attached to an outer surface of the half-split member, and one end of the coil spring is engaged with the support member. 4. An image forming apparatus comprising: an electrophotographic photosensitive member on which an electrostatic latent image is formed; and a developing unit for developing the electrostatic latent image, wherein the developing unit is any one of claims 1 to 3. An image forming apparatus formed on the developing cartridge according to the above item.