JPH05303239A - Process cartridge and image forming device using process cartridge - Google Patents

Abstract

PURPOSE:To restrain the run-out of the rotary shaft of a photosensitive drum and to form a high-definition image. CONSTITUTION:A supporting shaft 4h attached to a housing 4e is fitted in the inner periphery at the end of the photosensitive drum 4a, the photosensitive drum 4a is supported by the shaft 4h so that it can freely slide and rotated, and a developing means 4c is fixed in the housing 4e. Since the photosensitive drum 4a is directly supported by the supporting shaft 4h, the run-out in the rotation of the photosensitive drum 4a is reduced and image blurring is restrained.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a process cartridge and an image forming apparatus used in a copying machine, a printer or the like using an electrophotographic system, and more specifically, it is possible to minimize uneven rotation of an image carrier. The present invention relates to a process cartridge and an image forming apparatus using the process cartridge.

[0002]

2. Description of the Related Art An image forming apparatus such as a copying machine forms a latent image by selectively exposing a uniformly charged image carrier to form a latent image, and the latent image is visualized with toner. Image recording is performed by transferring the toner image to the recording material. In such an apparatus, the toner has to be replenished each time it runs out, but this toner replenishment work is not only troublesome, but it may be contaminated. In addition, maintenance of each member can be performed only by a specialized service person, which often causes inconvenience to the user.

Therefore, as shown in FIG. 7, a photosensitive drum 50 which is an image carrier, a charging device 51, a developing device 52, and a cleaning section.
53 and the like are integrated into a housing 54 to form a cartridge, so that the user can replace the parts such as toner replenishment and the image carrier which has reached the end of life by loading the cartridge into the apparatus main body. It has been put into practical use for easy maintenance.

In such a cartridge, in order to rotatably mount the photosensitive drum 50, as shown in FIG. 8, hollow flanges 55a, 55b are provided at both ends of the photosensitive drum 50.
The support shaft 56 fixed to the housing 54 is fitted into the flanges 55a and 55b so as to be rotatably supported.

[0005]

However, in the above-mentioned structure, the photosensitive drum 50 is swung with respect to the center of rotation c by the amount of coaxiality error of the inner and outer diameters of the flanges 55a and 55b.
Therefore, when the photosensitive drum 50 rotates, the positional accuracy with respect to each process means such as the developing means 52 arranged close to the drum 50 changes by the amount of the coaxial error, and the following inconvenience occurs.

For example, regarding the relationship with the charging section 51, uneven charging occurs at every rotation cycle of the photosensitive drum 50, which causes uneven density of an image. Regarding the relationship with the developing section 52, due to an error between the developing sleeve 52a and the photosensitive drum 50,
Development unevenness may occur for each rotation cycle of the photosensitive drum 50. Regarding the relationship with the cleaning unit 53, due to an error between the cleaning blade 53a and the photosensitive drum 50,
Cleaning failure or toner may be fused to the surface of the photosensitive drum at each rotation cycle of the photosensitive drum 50.

Therefore, it is necessary to make the flanges 55a and 55b highly accurate in order to guarantee the positional accuracy of each member so that the above-mentioned error does not occur, but the cost of parts is increased and more inspection processes are required. Let's go.

Therefore, as shown in FIG. 7, a charging unit 51 is conventionally used.
There is an example in which the spacer 57 is interposed between the developing sleeve 52a and the photosensitive drum 50, and the charging unit 51 and the like are swung following the rotational shake of the photosensitive drum 50. Vibration caused by contact rotation causes image blur.

The present invention is to solve the above-mentioned conventional problems, and an object of the present invention is to provide a process cartridge and a process cartridge capable of minimizing the rotational shake of the image carrier with a simple structure. An image forming apparatus to be used is provided.

[0010]

A typical constitution of the present invention for achieving the above object comprises an image carrier and at least one process means acting on the image carrier, and a cylindrical image carrier. It is characterized in that the inner periphery of at least one end of the body is rotatably supported by a support member attached to the housing, and at least one of the process means is fixed to the housing to form a process cartridge.

The process cartridge is loaded,
It is characterized by configuring an image forming apparatus capable of obtaining a high-definition image.

[0012]

In the process cartridge having the above structure, the image carrier is supported by the support member on the inner circumference thereof without the flange, so that the rotational shake of the image carrier can be suppressed to a small level. Further, since at least one of the process means such as the developing means is fixed to the housing for fixing the supporting member, the positional relationship between the image carrier and the process means is kept constant.

Therefore, when an image is formed by using the above-mentioned cartridge, the occurrence of image unevenness is prevented, and a high quality image can always be obtained stably.

[0014]

【Example】

First Embodiment Next, an image forming apparatus according to a first embodiment of the present invention will be described with reference to FIGS. still,
FIG. 1 is a structural explanatory view of an image forming apparatus with a process cartridge loaded therein, FIG. 2 is a structural explanatory view of the process cartridge, FIG. 3 is an external explanatory view of the process cartridge, and FIG. 5A and 5B are explanatory views showing a loading configuration of the cartridge to the image forming apparatus.

[Overall Description of Image Forming Apparatus] First, the overall configuration of the image forming apparatus will be briefly described. This device is shown in Figure 1.
As shown in FIG. 2, the recording material 2 fed from the feeding portion 1 is conveyed by the conveying means 3 and an image is formed in the image forming portion having the process cartridge 4 loaded therein. 2. Transfer the image to 2. Then, the recording material 2 is conveyed to the fixing portion 6 to fix the image on the recording material 2, and is discharged by the discharging roller 7 to the discharging portion 8 in the upper part of the apparatus. The process cartridge 4 is detachably mounted on the apparatus main body 9 so as to be replaceable.

The exposure of the image forming unit is performed by the scanner unit 10.
Sent from. That is, the image signal is the laser diode 10
When given to a, the laser diode 10a irradiates the polygon mirror 10b with image light corresponding to the image signal. The polygon mirror 10b is rotated at a high speed by a scanner motor 10c, and the image light reflected by the polygon mirror 10b is irradiated from the exposure section of the process cartridge 4 via the imaging lens 10d and the reflection mirror 10e to selectively image the image carrier. It is configured to be exposed to.

Next, the structure of each part of the process cartridge and the image forming apparatus will be sequentially described in detail.

{Feeding unit} The feeding unit 1 feeds the recording material 2 to the image forming unit, and the paper feed cassette 1a containing a plurality of recording materials 2 is loaded in the apparatus main body 9. .. At the time of image formation, the feeding roller 1b is driven to rotate in accordance with the image forming operation, and the recording materials 2 in the cassette 1a are separated and fed one by one, and are guided and fed by the guide plate 1c.

{Conveying means} The conveying means 3 conveys the recording material 2 fed from the feeding means 1 to the image forming section, and
The sheet is conveyed to the fixing unit 6. That is, the recording material 2 separated and fed from the feeding unit 1 is applied to the registration roller pair 3a, 3b.
The recording material 2 after being image-formed while being conveyed at the timing
Is transported to the fixing unit 6 by the transport roller 3c and the guide plate 3d.

{Process Cartridge} Next, a process cartridge will be described. It has an image carrier and at least one process means. Here, the process means includes, for example, a charging means for charging the surface of the image carrier, a developing means for forming a toner image on the image carrier, a cleaning means for cleaning the toner remaining on the surface of the image carrier, and the like.

The process cartridge 4 of this embodiment is shown in FIG.
As shown in FIG. 2, a charging means 4b, a developing means 4c containing toner (developer), and a cleaning means 4d are arranged around the electrophotographic photosensitive drum 4a which is an image carrier, and these are shown in FIG. As shown in the drawing, the cartridge is integrally covered with the housing 4e to form a cartridge, which is detachably attached to the apparatus main body 9.

Next, the structure of each part of the process cartridge 4 will be individually described.

(Photosensitive Drum) The photosensitive drum 4a according to this embodiment is constituted by coating an organic photoconductor layer 4a2 on the outer peripheral surface of a cylindrical aluminum cylinder 4a1. As shown in FIG. Both ends are rotatably supported by support members. By transmitting the driving force of a drive motor (not shown), the photosensitive drum 4a is configured to rotate in the arrow direction of FIG. 1 in accordance with the image forming operation. The rotation support structure of the photosensitive drum 4a will be described later.

(Charging Means) The charging means 4b is disclosed in JP-A-63-14.
A so-called contact charging method as shown in Japanese Patent No. 9669 is used, in which a conductive roller is brought into contact with the photosensitive drum 4a,
The surface of the photosensitive drum 4a is uniformly charged by applying a voltage to the conductive roller.

The process cartridge 4 is provided with an exposure unit 4f for irradiating the photosensitive drum 4a charged by the charging unit 4b with the image light from the scanner unit 10 to form a latent image. ..

(Developing means) In order to visualize the latent image, a developing means 4c capable of developing toner is arranged.

As shown in FIG. 2, the developing means 4c is provided with a toner feeding mechanism 4c2 inside the container 4c1 for storing the toner, which rotates and sends the toner to the front portion of the container 4c1.
Further, a blade 4c3 and a sleeve 4c4 which is a developer carrying member are attached to the tip of the container to which the toner is fed by the feeding mechanism 4c2.

When forming an image, the developing means 4c is driven to sequentially form a visible image with the toner on the photosensitive drum 4a. That is, the toner in the container 4c1 is fed to the tip of the container by the feeding mechanism 4c2, a thin layer of toner is applied to the outer circumference of the rotating sleeve 4c4 by the blade 4c3, and an electric charge is applied to the toner. By applying a developing bias between the sleeve 4c4 and the photosensitive drum 4a on which the latent image is formed, toner development is performed on the photosensitive drum 4a according to the latent image.

The developing means 4c is positioned by a positioning mechanism (not shown) so that the sleeve 4c4 and the photosensitive drum 4a face each other with a minute gap (about 250 .mu.m), and the sleeve 4c4 is provided in the main body 9 of each color developing device. It is connected to a high voltage power source for application and a voltage is applied during development.

(Protective Cover) The photosensitive drum 4a is provided by the developing means 4c positioned with respect to the photosensitive drum 4a.
Since the toner visualized above is transferred to the recording material 2 on the transfer drum 3, the photosensitive drum 4a is formed at the time of image formation.
Is exposed and faces the transfer drum 3. However, since the process cartridge 4 is attached to and detached from the apparatus main body 9, if the photosensitive drum 4a is exposed when the process cartridge 4 is removed from the apparatus main body 9, dust or the like is attached or external light is emitted. It is exposed to water and deteriorates. Therefore, in this embodiment, as shown in FIG. 2, the housing 4e is provided with a protective cover 4g1 which can be opened and closed.

The protective cover 4g is attached in such a manner that it can be opened and closed by moving it in the direction of the arrow in FIG. 2, and is biased in the closing direction by a spring or the like (not shown). As shown in FIG. 2, the photosensitive drum 4a is closed so that external light does not strike it. And process cartridge 4
2 is loaded into the apparatus main body 9, the protective cover 4g is moved in the arrow direction in FIG. 2 and opened by a mechanism (not shown), and the photosensitive drum 4a is exposed to face the transfer drum 3. ..

The exposure section 4f is also provided with a protective cover 4g2 which opens and closes in association with the loading of the cartridge 4.

(Cleaning Means) The cleaning means cleans the toner remaining on the photosensitive drum 4a after the toner visualized on the photosensitive drum 4a by the developing means 4c is transferred to the recording material 2. As shown in FIG. 2, the cleaning means 4d of this embodiment comprises a waste toner container 4d1, a blade 4d2, and a squeeze sheet 4d3. The toner remaining on the photosensitive drum 4a is removed by the blade as the photosensitive drum 4a rotates. It is scraped off by 4d2, guided to the waste toner container 4d1 by a squeeze sheet 4d3, and sent to the inner part of the container by a stirring member (not shown).

The charging means 4b, the developing means 4c, and the cleaning means 4d are attached to the housing 4e such that they are fixed or fixed by screws.

(Rotation Supporting Structure of Photosensitive Drum) Next, a structure for rotatably supporting the photosensitive drum 4a will be described with reference to FIG.

Fitting holes 4 are formed on both sides of the housing 4e.
A hole e1 is bored, and a support shaft 4h, which is a support member, is fitted into the fitting hole 4e1 and is fixed by a screw 4i. The boss portion 4h1 of the support shaft 4h is fitted to the inner circumference of the cylindrical photosensitive drum 4a, and rotatably supports the photosensitive drum 4a.

The boss 4h1 and the inner circumference of the photosensitive drum form a clearance fit which is slidable, and the support shaft 4h is made of a self-lubricating plastic such as polyacetal to smoothly move the photosensitive drum 4a. It is configured to slide and rotate.

A gear flange 4j is attached to one end of the photosensitive drum 4a in the axial direction, and the gear flange 4j meshes with a drive gear 13 connected to a drive motor to receive a rotational force.

{Structure for Loading Process Cartridge in Apparatus Main Body} Next, the structure for attaching and detaching the process cartridge 4 to and from the apparatus main body 9 will be described. An upper opening / closing cover 12 is attached to the device body 9 so as to be openable / closable about a shaft 11 shown in FIG. 1, and can be locked and unlocked by a hook (not shown).

The upper opening / closing cover 12 has a U-shaped cross section, and has guide rails for supporting both ends of the process cartridge 4 on both side walls, as shown in FIGS. 5 (a) and 5 (b). 12a are provided facing each other. This guide rail
The reference numeral 12a is configured to guide the lower portion of the process cartridge 4 and to be inclined obliquely forward with the opening / closing cover 12 closed. Therefore, when the process cartridge 4 is loaded, as shown in FIG.
12 is opened, the lower part of the process cartridge 4 is placed on the guide rail 12a, and is inserted and loaded. When the open / close cover 12 is closed in this state, the protective cover 4g is automatically opened, and the exposed gear flange 4j of the photosensitive drum 4a meshes with the drive gear 13 on the apparatus main body 9 side.

On the other hand, when removing the cartridge 4, the opening / closing cover 12 is opened in the opposite manner to the above, and the protective cover 4g is opened.
Automatically closes, and the cartridge 4 is guided by the guide rail 12a.
Just pull it out along.

Since the process cartridge 4 is mounted on the upper opening / closing cover 12, the process cartridge 4 moves upward together with the opening / closing cover 12 when the cover 12 is opened. As a result, the conveyance path of the recording material 2 is exposed, so that the jam (paper jam) process can be easily performed.

{Transfer Means} The transfer means 5 is the photosensitive drum 4a.
It is for transferring the toner image formed on the recording material 2 to the recording material 2. In this embodiment, as shown in FIG. 1, it is composed of a transfer roller 5. That is, the transfer roller 5 is configured to press the recording material 2 against the photosensitive drum 4a of the loaded process cartridge 4 by the transfer roller.
The toner on the photosensitive drum 4a is transferred to the recording material 2 by applying a voltage having a polarity opposite to that of the toner.

{Fixing Unit} Next, the fixing unit 6 is for fixing the image formed on the recording material 2 wound around the transfer drum 3 by the process cartridge 4, and is driven to rotate as shown in FIG. A roller 6a and a fixing roller 6b that presses against the roller 6a and applies heat and pressure to the recording material 2.
Consists of. That is, the recording material 2 separated from the transfer drum 3 is conveyed by the drive roller 6a when passing through the fixing portion 6, and heat and pressure are applied by the fixing roller 6b. As a result, the image forming toner is fixed on the recording material 2.

[Image Forming Operation] Next, the operation of forming an image by the apparatus having the above-described structure will be described. The feeding roller 1b shown in FIG. 1 is rotated to remove the recording material 2 in the paper feeding cassette 1a. Separate the sheets and register roller pair 3a, 3
Feed to b. The photosensitive drum 4a is rotated in the direction of the arrow in FIG. 1 in synchronism with the conveyance timing of the pair of registration rollers 3a and 3b, and the drum surface is uniformly charged by the charging means 4b with respect to the drum 4a, and the scanner unit 10 is also provided.
Thus, the image is irradiated with light to form a latent image on the photosensitive drum 4a. Simultaneously with the formation of this latent image, the developing means 4c of the process cartridge 4 is driven, and a voltage having substantially the same potential as the charging polarity of the photosensitive drum 4a is applied so that the toner adheres to the latent image on the photosensitive drum 4a. Then, the toner is developed, and a voltage having a polarity opposite to that of the toner is applied to the transfer roller 5 to transfer it to the toner recording material 2 on the photosensitive drum 4a.

The recording material 2 on which the toner image is formed as described above is conveyed to the fixing portion 6 by the conveying roller 3c.
The fixing unit 6 applies heat and pressure to fix the toner, and then the discharge roller 7 discharges the toner to the discharge tray 8 to complete the image formation.

In the process cartridge 4,
Since the boss portion 4h1 of the support shaft 4h is directly fitted to the inner circumference of the photosensitive drum 4a and the drum 4a is rotatably supported, unlike the conventional case, the rotation shaft of the photosensitive drum 4a is not supported. Shake can be suppressed, and high-quality image formation without image blur can be performed.

[Second Embodiment] In the above-described first embodiment, the support shafts 4h are fitted to both ends of the photosensitive drum 4a so that the photosensitive drum 4a can be inserted.
Although an example in which a is rotatably supported is shown, the photosensitive drum 4a may be rotatably supported by configuring as shown in FIG. 6A is an explanatory view of the supporting portion of the photosensitive drum 4a, and FIG. 6B is a sectional view taken along the line AA of FIG.

In the supporting structure shown in FIG. 6, the inner circumference of both ends of the photosensitive drum 4a is supported by three sliding pieces 14a, 14b, 14c. The sliding pieces 14a, 14b, 14c are fixed to the inner surface of the housing 4e with screws 15, respectively, and are evenly spaced in the circumferential direction of the photosensitive drum 4a.
It is attached so as to accurately contact the inner peripheral surface of a.

The end portions a of the sliding pieces 14a, 14b, 14c or the reference pin b protruding from the sliding pieces 14a, 14b, 14c are provided with a charging means, a developing means, a cleaning means, etc. which are process means. By making contact or fitting, the positional relationship between the photosensitive drum 4a and these process means can be maintained with high accuracy.

[Other Embodiments] In the above-described first and second embodiments, the inner circumferences of both ends of the photosensitive drum 4a are supported by the supporting members. Support only the other end, attach a flange etc.,
Even if this flange is supported, some effect can be expected.

For example, in the first embodiment, due to the space limitation of the gear flange 4j shown in FIG. 4, the inner periphery of the side where the gear flange 4j is not provided is supported by the support shaft 4h, and the side where the gear flange 4j is provided is When the flange 4j is configured to be supported by the support shaft 4h, the durability and the effect of preventing shaft shake of the photosensitive drum 4a can be confirmed as compared with the conventional example.

In the second embodiment, three sliding pieces 14a,
Although the photosensitive drum 4a is supported by 14b and 14c, it goes without saying that the number of sliding pieces need not be three.

Further, the present invention is not limited to the case of forming a single color image as in the above-described embodiment, but a plurality of developing means 4c are provided to form a plurality of color images (for example, a two color image, a three color image or a full color image). It can be suitably applied to a cartridge to be formed.

As the developing method, various known developing methods such as a two-component magnetic brush developing method, a cascade developing method, a touchdown developing method and a cloud developing method can be used.

As for the structure of the charging means, the so-called contact charging method was used in the above-mentioned first embodiment, but a metal shield such as aluminum is provided around the three sides of a tungsten wire which has been conventionally used as another structure. It is of course possible to use a configuration in which positive or negative ions generated by applying a high voltage to the tungsten wire are moved to the surface of the photosensitive drum 4a and the surface of the drum 4a is uniformly charged. ..

Further, as a method for cleaning the toner remaining on the photosensitive drum 4a, the cleaning means may be constituted by using a blade, a fur brush, a magnetic brush or the like.

The above-mentioned process cartridge is
For example, an electrophotographic photosensitive member as an image carrier and at least one of process means are provided. Therefore, as the mode of the process cartridge, in addition to the embodiment described above, for example, the image carrier and the charging unit are integrally made into a cartridge, which can be attached to and detached from the apparatus main body. The image carrier and the developing means are integrally made into a cartridge, which can be attached to and detached from the main body of the apparatus. The image carrier and the cleaning means are integrally made into a cartridge so that it can be attached to and detached from the apparatus main body. Further, there is one in which an image carrier and two or more of the above-mentioned process means are combined into an integrated cartridge so that it can be attached to and detached from the apparatus main body.

Further, although the laser beam printer is illustrated as the image forming apparatus in the above-mentioned embodiments, the present invention is not limited to this, and it is naturally possible to use it for other image forming apparatus such as a copying machine. is there.

[0062]

As described above, according to the present invention, since the inner periphery of the image bearing member is rotatably supported by the supporting member,
It is possible to suppress the shake of the rotating shaft of the image carrier and to keep the gap between the image carrier and each process means constant.

Therefore, by using the process cartridge, it is possible to prevent the occurrence of image unevenness and form a high-definition image.

[Brief description of drawings]

FIG. 1 is an overall schematic explanatory view of an image forming apparatus according to an embodiment of the present invention.

FIG. 2 is an explanatory diagram of a configuration of a process cartridge.

FIG. 3 is an external view of a process cartridge.

FIG. 4 is an explanatory diagram of a rotation support structure of a photosensitive drum.

FIG. 5 is an explanatory diagram of a loading configuration of a process cartridge.

FIG. 6 is an explanatory diagram of a rotation support structure of a photosensitive drum according to a second embodiment.

FIG. 7 is an explanatory diagram of a process cartridge according to a conventional technique.

FIG. 8 is an explanatory diagram of a rotation support structure of a photosensitive drum according to a conventional technique.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Feeding section 2 ... Recording material 3 ... Conveying means 4 ... Process cartridge 4a ... Photosensitive drum 4b ... Charging means 4c ... Developing means 4d ... Cleaning means 4e ... Housing 4f ... Exposure section 4g1, 4g2 ... Protective cover 4h ... Support Shaft 5 ... Transfer roller 6 ... Fixing unit 7 ... Ejection roller 8 ... Ejection unit 9 ... Device body 10 ... Scanner unit 12 ... Upper opening / closing cover 14a, 14b, 14c ... Sliding piece

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Hiroyuki Shirai 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc.

Claims (7)

[Claims] 1. A process cartridge having an image bearing member and at least one process means acting on the image bearing member, wherein a support member having an inner periphery of at least one end of the tubular image bearing member attached to a housing. A process cartridge, wherein the process cartridge is rotatably supported by, and at least one of the process means is fixed to the housing. 2. The process cartridge according to claim 1, wherein the process cartridge has a developing unit as one process unit. 3. The process cartridge according to claim 1, wherein the process cartridge has a charging unit as one process unit. 4. The process cartridge according to claim 1, wherein the process cartridge has a cleaning unit as one process unit. 5. The process cartridge comprises an electrophotographic photosensitive member as an image carrier, a developing unit, and a charging unit or a cleaning unit, which are integrally formed into a cartridge,
The process cartridge according to claim 1, wherein the process cartridge is removable from the main body of the apparatus. 6. The process cartridge comprises an electrophotographic photosensitive member as an image bearing member, a charging unit, a developing unit,
The process cartridge according to claim 1, wherein the cleaning unit and the cleaning unit are integrally formed into a cartridge, and the cartridge is detachably attached to the apparatus main body. 7. An image carrier and at least one process means acting on the image carrier, wherein at least one end of the cylindrical image carrier is rotatably supported by a support member attached to a housing. A loading section for supporting and further loading at least one of the process means to the housing for loading a process cartridge; a recording material is conveyed to the image carrier to remove a developer from the image carrier. An image forming apparatus comprising: a conveying unit configured to convey the transferred recording material to a discharge unit.