JPH08179675A - Process cartridge and image forming device - Google Patents

Abstract

PURPOSE: To provide a process cartridge and an image forming device capable of stably bringing a developing member into contact with an electrophotographic photoreceptor by means of a small pressing force and reducing the number of parts so as to reduce costs. CONSTITUTION: The process cartridge B is provided with a first frame body 11 having an electrophotographic photoreceptor and a second frame body 12 having a developing member 9d and constructed in a manner that the second frame body 12 is coupled with the first frame body 11 so as to be rotated and the developing member 9d is brought into contact with the electrophotographic photoreceptor body. The image forming device is constructed, being provided with a loading means for loading the process cartridge B and a pressing means for pressing the second frame with the process cartridge B loaded and pressing the developing member 9d to the electrophotographic photoreceptor.

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 for forming an image by an electrophotographic method.

[0002]

2. Description of the Related Art In an image forming apparatus such as a printer, a latent image is formed by selectively exposing an electrophotographic photosensitive member uniformly charged by a charging device, and the latent image is developed with a developer by a developing device. At the same time as visualizing, the image formed by the developer is transferred to a recording medium to record an image. In such a device, the maintenance of each member was performed by a professional service person.

Therefore, the electrophotographic photosensitive member, the charging device, the developing device, the cleaning unit and the like are integrally formed into a cartridge so that the user can load the cartridge into the apparatus main body to replenish the developer. It has been put into practical use that parts such as electrophotographic photoreceptors that have reached the end of their life can be replaced and maintenance is facilitated.

In such a process cartridge, a part of the developing roller, which is a developing member, is brought into contact with the electrophotographic photosensitive member so that the roller and the electrophotographic photosensitive member face each other with a minute gap. There is. for that reason,
As shown in FIG. 6, the electrophotographic photosensitive member 51 is rotatably attached to the first frame body 50, and the developing roller 53 is attached to the second frame body 52.
Rotatably attached to the first frame 50 and a rotation shaft
The second frame body 52 is connected by 54, and the second frame body is pressed by the spring 55 to press the developing roller 53 toward the electrophotographic photosensitive member 51 side.

That is, a spring stopper provided on the first frame 50
A pressing spring 55 is attached to 56, and the second frame 52 is a developing roller 53.
The developing frame body 52a that supports the developing chamber 52a and the toner frame body 52b that configures the toner storage portion are integrally welded to each other. By pressing the arrow m with respect to the second frame 52
Gives a directional moment. As a result, the developing roller 53
By making cap-shaped spacers attached to the outer periphery of both ends contact the electrophotographic photosensitive member 51, the electrophotographic photosensitive member 51 and the developing roller 53 are configured to maintain an appropriate distance.

[0006]

However, extending the developing frame 52a having high rigidity above the toner frame 52b reduces the amount of toner stored. Therefore, it is difficult to increase the distance from the rotating shaft 54 (fulcrum) to the pressing spring 55 (power point).

Therefore, since the position where the developing frame 52a is pressed by the spring 55 is close to the rotary shaft 54,
It is necessary to increase the pressing force, and the pressing means and the holding means must be arranged near the rotating shaft 54, so that the number of parts is increased.

The present invention is to solve the above-mentioned conventional problems, and an object thereof is to provide a small pressing force.
An object of the present invention is to provide a process cartridge and an image forming apparatus that can stably bring the developing member into contact with the electrophotographic photosensitive member and further reduce the number of parts to reduce the cost.

[0009]

A typical structure according to the present invention for achieving the above object is a process cartridge detachable from an image forming apparatus main body, comprising: a first frame having an electrophotographic photosensitive member; A second frame member having a developing member, the second frame member is rotatably coupled to the first frame member, and the developing member can be brought into contact with the electrophotographic photosensitive member. It becomes a feature.

Also, mounting means for mounting the process cartridge, and pressing means for pressing the second frame body to press the developing member against the electrophotographic photosensitive member while the process cartridge is mounted, The image forming apparatus is characterized in that a transfer means for transferring the image formed on the electrophotographic photosensitive member to a recording medium and a conveying means for conveying the recording medium are provided.

Further, it is characterized in that the process cartridge is pressed against the positioning member of the apparatus main body and positioned by the pressing by the pressing means.

Further, the pressing means is provided on an opening / closing cover which can be opened / closed on the main body of the apparatus.

[0013]

In the above structure, since the process cartridge is not provided with the pressing means for pressing the second frame body and the first frame body, it is possible to reduce the number of parts of the process cartridge which is a consumable item. Also, the structure can be simplified.

When the pressing means is provided on the opening / closing member of the image forming apparatus, when the process cartridge is mounted and the opening / closing member is closed, the second frame is pressed and the developing member is securely attached to the electrophotographic photosensitive member. Abut. Further, at this time, by positioning the process cartridge in the apparatus main body, the number of positioning parts can be reduced.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described with reference to the drawings.

First Embodiment First, a process cartridge according to the first embodiment and an image forming apparatus to which the process cartridge can be attached will be specifically described with reference to FIGS. 1 to 3.
1 is an explanatory view of the structure of the image forming apparatus, FIG. 2 is an explanatory view of the structure of the process cartridge, and FIG. 3 is an explanatory view of the arrangement of the pressing springs.

Here, as the order of the description, the overall structure of the process cartridge and the image forming apparatus using the process cartridge will be described first, and then the structure of pressing the developing member against the electrophotographic photosensitive member will be described.

{Overall Configuration} This image forming apparatus A is shown in FIG.
As shown in FIG. 3, a light image based on image information is emitted from an optical system 1 including a laser diode 1a, a polygon mirror 1b, a lens 1c, a mirror 1d, etc. to form a toner image on an electrophotographic photosensitive member which is an image carrier. This is an electrophotographic image forming apparatus. Then, in synchronization with the formation of the toner image, the recording medium 2 is conveyed from the cassette 3a by the conveying means 3 including the pickup roller 3b, the conveying roller pair 3c, the registration roller pair 3d, and the like, and is made into a process cartridge B as a cartridge. In the image forming section, the toner image formed on the electrophotographic photosensitive member is transferred to the recording medium 2 by applying a voltage to the transfer roller 4 as a transfer unit. Then, the recording medium 2 after the image transfer is guided by the guide member 3e, and the fixing rotating body 5a having a built-in heater and the driving roller 5b for pressing and conveying the recording medium 2 against the rotating body 5a.
Then, the transferred toner image is fixed on the recording medium 2. Then, the recording medium 2 is ejected onto the ejection roller pair 3
It is configured to be conveyed by f and 3 g and discharged to the discharge unit 6.

On the other hand, in the process cartridge B forming the image forming portion, as shown in FIG. 2, a photosensitive drum 7 having a photosensitive layer which is an electrophotographic photosensitive member is rotated and the surface thereof is charged by a charging means. The roller 8 is uniformly charged by applying a voltage, and the optical image from the optical system 1 is exposed on the photosensitive drum 7 through the exposure unit to form a latent image, and the developing unit 9 is provided.
It is configured to be developed by.

In the developing means 9, the toner in the toner storage portion 9a is fed by the toner feeding member 9b, the developing roller 9d which is the developing member having the fixed magnet 9c built therein is rotated, and the developing blade 9e imparts the triboelectric charge. The formed toner layer is formed on the surface of the developing roller 9d, and the toner is transferred to the photosensitive drum 7 according to the latent image to form a toner image and visualize it.

After a voltage having a polarity opposite to that of the toner image is applied to the transfer roller 4 to transfer the toner image to the recording medium 2, the cleaning blade 10a is used for the photosensitive drum 7.
Scrape off the toner remaining on the
The cleaning means 10 collects the residual toner on the photoconductor drum 7 by scooping by b and collecting it in the waste toner storage portion 10c.

Each of the components such as the photosensitive drum 7 is supported by a cartridge frame body in which a first frame body 11 and a second frame body 12 are combined to form a cartridge, which is provided in the apparatus main body 13. It is detachably attached to the attachment means.

The cartridge mounting means comprises a rotating shaft 14a.
When the opening / closing member 14 is opened around the center, a cartridge mounting space is provided, and cartridge mounting guide portions are provided on the left and right inner side surfaces of the apparatus body 13 so as to face each other. As shown in FIG. 1, guide rails 15 for inserting the process cartridge B are provided opposite to the left and right guide portions so as to face each other. On the other hand, on both outer side surfaces of the process cartridge B, there are provided cylindrical protrusions 16 protruding outward from the rotation center position of the photosensitive drum 7, and these columnar protrusions 16 are provided along the guide rails 15 so as to extend along the process cartridge. Insert B and drop it into the positioning recess 15a provided at the end of the guide rail 15. Then, a moment in the direction of arrow a in FIG. 1 is applied to the process cartridge B centering on the cylindrical protrusion 16 so that the first frame 11 is abutted against the abutting portion 17 of the apparatus main body 13 for positioning and mounting. It is a thing.

{Structure of pressing developing member against photosensitive drum} The developing roller 9d of the process cartridge is developed with the photosensitive drum 7 by contacting the photosensitive drum 7 with cap-shaped spacers attached to both outer circumferences. The roller 9d is configured to maintain an appropriate distance. Therefore, the developing roller 9d is configured to be pressed against the photosensitive drum 7. Next, the pressing structure will be described.

As shown in FIG. 2, the first frame 11 rotatably supports the photosensitive drum 7, the cleaning blade 10a, and a waste toner storage portion 10c. On the other hand, the second frame body 12 supports the developing means 9, and is constituted by welding the toner frame body 12a and the developing frame body 12b at the joint portion and integrating them. The toner frame 12a
Is a component of the toner storage portion 9a.
Reference numeral b denotes a developing chamber that supports the developing roller 9d and the developing blade 9e.

An arm portion 12b1 is formed on the developing frame body 12b, and the arm portion 12b1 is rotatably attached to the first frame body 11 by a rotary shaft 18. That is, the second frame body 12 is rotatably connected to the first frame body 11.

Incidentally, in this process cartridge B, like the conventional process cartridge, the second frame 12
No pressing means for pressing the developing roller 9d attached to the photosensitive drum 7 attached to the first frame 11 is provided. Therefore, the number of parts constituting the process cartridge B is reduced, the assembling process is simplified, and the cost of the process cartridge B, which is a consumable item, can be reduced.

On the other hand, the opening / closing member 14 of the image forming apparatus A includes
As shown in FIG. 1, a pressing spring 19 serving as a pressing means is attached to the inner surface. This pressing spring 19 is shown in FIG.
As shown in the drawing), a leaf spring is attached at a substantially central position in the longitudinal direction of the mounted process cartridge B (in the rotation axis direction of the photoconductor drum 7). When the opening / closing member 14 is closed, the spring 19 moves to the first position. The upper end of the two-frame body 12 is pressed down. When the opening / closing member 14 is closed, it is locked in a closed state by a latch mechanism (not shown).

As a result, the process cartridge B is given a moment in the direction of the arrow a around the cylindrical protrusion 16 so that the upper end of the first frame 11 abuts against the abutting portion 17 and is positioned within the apparatus main body 13. To be done. At this time, the second frame
The developing roller 9d is pressed against the photosensitive drum 7 because the moment 12 is applied to the rotating shaft 18 in the direction of the arrow a. As a result, the developing roller 9d and the photosensitive drum 7 face each other with a minute gap corresponding to the thickness of the cap-shaped spacers attached to both ends of the developing roller 9d.

Here, the pressing position of the pressing spring 19 with respect to the process cartridge B is the upper portion of the toner frame 12a,
The distance between the position (power point) and the rotation center (fulcrum) of the second frame 12 is about 10 times longer than the distance of the pressing position by the spring with respect to the rotation center of the conventional developing frame. Therefore, the pressing force by the pressing spring 19 in the present embodiment may be a weak force of about 1/10 as compared with the conventional pressing force. Therefore, the thickness of the developing frame 12b can be reduced, and the cost can be reduced. Even when the toner frame 12a having a low wall thickness is pressed, the frame 12a is bent. There are few things.

Further, since the weak pressing force is sufficient, as shown in FIG. 3, the pressing by the pressing spring 19 is sufficient at one position in the longitudinal direction of the process cartridge B, and the pressing of the process cartridge B against the apparatus main body 13 is caused by this pressing. It can also be positioned.

Further, since the pressing spring 19 is a leaf spring that fits inside the opening / closing cover 19 when the opening / closing member 14 is closed, it is not necessary to reduce the volume of the toner storage portion 9a.
In addition, since the pressing spring 19 only needs to be attached to the inner surface of the opening / closing member 14, it is attached to a wide flat surface, has good workability, and can be easily attached by a so-called snap fit or the like.

Furthermore, when the latch mechanism of the opening / closing member 14 is removed, the opening / closing member 14 is lifted by the biasing force of the pressing spring 19, so that the opening / closing member 14 is easily opened, and it is necessary to separately provide a structure for lifting the opening / closing member 14. Absent.

[Second Embodiment] Next, a second embodiment of the pressing means will be described with reference to FIGS. Since the basic structure of the process cartridge and the image forming apparatus according to the second embodiment is the same as that of the first embodiment described above, only the structure of the pressing spring as the pressing means will be described here. The same members as those in the first embodiment described above are designated by the same reference numerals.

In the first embodiment described above, the pressing spring
Although the example is shown in which 19 is provided at one location substantially in the longitudinal center of the process cartridge B, two or more locations in the longitudinal direction of the process cartridge B may be pressed by the pressing springs.

For example, as shown in FIG. 4 (a view corresponding to the arrow C in FIG. 1), pressing springs 19 are attached to two inner surfaces of the opening / closing member 14, and the pressing springs 19 are provided on both sides of the process cartridge B in the longitudinal direction. Is configured to be pressed. With this arrangement, the pressing force per pressing spring 19 is half that in the first embodiment, and the pressing force of the developing roller 9d against the photosensitive drum 7 is improved in the longitudinal balance.

FIG. 5 (a view corresponding to the arrow C in FIG. 1)
As shown in FIG. 5, a pressing spring 20 having a large number of spring portions 20a is attached to the inner surface of the opening / closing member 14, and the pressing spring portion 20a is configured to uniformly press the entire length of the process cartridge B in the longitudinal direction. With this, 1
The pressing force of each pressing spring portion 20a is extremely small and sufficient, and the developing roller 9d for the photosensitive drum 7 is sufficient.
The pressing force of is also balanced in the longitudinal direction.

[Other Embodiments] Next, other examples of each part of the above-mentioned embodiment will be described.

In the above-described embodiment, the leaf spring is used as the pressing means for the process cartridge B.
Of course, this may be another spring such as a coil spring, or the spring property of the opening / closing member 14 itself may be used.

Further, in the above-described embodiment, the pressing spring is attached to the opening / closing member 14, but the pressing spring can be attached to the process cartridge B side to obtain the same effect.

Further, the process cartridge B according to the present invention is not limited to the case of forming a single color image as described above, but a plurality of developing means are provided and a plurality of color images (for example, a two color image, a three color image or a full color image). The present invention can also be suitably applied to a cartridge that forms (1).

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.

The electrophotographic photoconductor is not limited to the photoconductor drum, but includes the followings. First, a photoconductor is used as the photoconductor, and examples of the photoconductor include amorphous silicon, amorphous selenium, zinc oxide, titanium oxide, and an organic photoconductor (OP).
C) etc. are included. The shape on which the photoconductor is mounted includes, for example, a drum-shaped, belt-shaped rotating body, a sheet-shaped body, and the like. Generally, a drum-shaped or belt-shaped one is used. For example, in the case of a drum type photoconductor, a photoconductor is vapor-deposited or coated on a cylinder of aluminum alloy or the like. Is.

As for the structure of the charging means, the so-called contact charging method was used in the above-described first embodiment, but a tungsten wire which has been conventionally used as another structure is provided with a metal shield such as aluminum around three sides. It goes without saying that a configuration may be used 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 to uniformly charge the surface of the drum.

The charging means may be of a blade type (charging blade), a pad type, a block type, a rod type, a wire type or the like other than the roller type.

Further, as a method for cleaning the toner remaining on the photosensitive drum, 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
It comprises at least an electrophotographic photosensitive member and a developing means. Therefore, as a typical mode thereof, as in the above-described embodiment, the developing means, the electrophotographic photosensitive member as the image carrier, the charging means and the cleaning means are integrally made into a cartridge, which can be attached to and detached from the apparatus main body. What to do. Further, the developing means, the electrophotographic photosensitive member as an image carrier, and the charging means or the cleaning means are integrally made into a cartridge, which can be attached to and detached from the apparatus main body. Further, there is one in which the developing means and the electrophotographic photosensitive member as the image bearing member are integrally made into a cartridge, which is attachable to and detachable from the apparatus main body.

Further, although the laser beam printer has been illustrated as the image forming apparatus in the above-mentioned embodiments, the present invention is not limited to this, and other image forming apparatus such as an electrophotographic copying machine, a facsimile machine or a word processor can be used. It is also possible to use for.

[0049]

As described above, according to the present invention, since the pressing means for abutting the developing member on the electrophotographic photosensitive member is not provided in the process cartridge, the number of parts of the process cartridge, which is a consumable item, is reduced to reduce the cost. Therefore, the structure can be simplified.

Since the pressing means is provided on the image forming apparatus side, when the process cartridge is mounted on the image forming apparatus, the developing member comes into contact with the electrophotographic photosensitive member. When the pressing means is provided on the opening / closing member that can be opened / closed with respect to the apparatus main body, when the process cartridge is mounted and the opening / closing member is closed, the second frame body is pressed and the developing member becomes the electrophotographic photosensitive member. Make sure they come into contact. At this time, since the distance between the rotation axis of the second frame and the pressing position becomes long,
The developing member can be reliably brought into contact with the electrophotographic photosensitive member with a small pressing force.

Further, the process cartridge is positioned in the main assembly of the apparatus by the pressing of the pressing means, so that the number of parts for positioning can be reduced.

[Brief description of drawings]

FIG. 1 is a configuration explanatory diagram 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 shows a pressing spring provided on the inner surface of the opening / closing member.
FIG.

FIG. 4 is an explanatory diagram of an embodiment in which two pressing springs are provided on the inner surface of the opening / closing member.

FIG. 5 is an explanatory diagram of an embodiment in which a large number of pressing spring portions are provided on the inner surface of the opening / closing member.

FIG. 6 is an explanatory diagram of a contact structure of a developing roller with respect to an electrophotographic photosensitive member according to a conventional technique.

[Explanation of symbols]

A ... Image forming apparatus, B ... Process cartridge, 1 ... Optical system, 1a ... Laser diode, 1b ... Polygon mirror, 1c ... Lens, 1d ... Mirror, 2 ... Recording medium, 3 ...
Conveying means, 3a ... Cassette, 3b ... Pickup roller, 3c ... Conveying roller, 3d ... Registration roller, 3e ...
Guide member, 3f, 3g ... Ejection roller, 4 ... Transfer roller, 5 ... Fixing unit, 5a ... Fixing rotating body, 5b ... Driving roller, 6 ... Ejection section, 7 ... Photosensitive drum, 8 ... Charging roller,
9 ... Developing means, 9a ... Toner storage section, 9b ... Toner feeding member, 9c ... Magnet, 9d ... Developing roller, 9e ... Developing blade, 10 ... Cleaning means, 10a ... Cleaning blade, 10b ... Squi sheet, 10c ... Waste toner storage Part, 11
... first frame, 12 ... second frame, 12a ... toner frame, 12b ...
Developing frame, 13 ... Device body, 14 ... Opening / closing member, 14a ... Rotating shaft, 15 ... Guide rail, 15a ... Recess, 16 ... Cylindrical protrusion,
17 ... Abutting part, 18 ... Rotating shaft, 19,20 ... Pressing spring

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Hiroki Nomura, 6651-1, Shimokagemori, Chichibu-shi, Saitama Prefecture (72) Masaaki Ichikawa 5379-1, Yokose, Yokose-cho, Chichibu-gun, Saitama Prefecture

Claims (10)

[Claims] 1. A process cartridge attachable / detachable to / from an image forming apparatus main body, comprising: a first frame body having an electrophotographic photosensitive member; and a second frame body having a developing member. A process cartridge characterized in that a second frame member is rotatably coupled so that the developing member can come into contact with the electrophotographic photosensitive member. 2. The process cartridge comprises a developing means, an electrophotographic photosensitive member as an image carrier, a charging means and a cleaning means, which are integrally formed into a cartridge, and the cartridge is attached to and detached from the main body of the image forming apparatus. The process cartridge according to claim 1, which is made possible. 3. The process cartridge comprises a developing unit, an electrophotographic photosensitive member as an image carrier, and a charging unit or a cleaning unit, which are integrally formed as a cartridge and can be attached to and detached from the main body of the image forming apparatus. The process cartridge according to claim 1, which is a product. 4. The process cartridge is a cartridge in which a developing unit and an electrophotographic photosensitive member as an image carrier are integrally formed as a cartridge and can be attached to and detached from the main body of the image forming apparatus. Process cartridge. 5. An image forming apparatus in which a process cartridge is detachable and which forms an image on a recording medium, having a first frame body having an electrophotographic photoreceptor and a second frame body having a developing member. Mounting means for mounting the process cartridge configured to rotatably connect the second frame body to the first frame body and to allow the developing member to contact the electrophotographic photosensitive member; A pressing unit for pressing the second frame body to press the developing member against the electrophotographic photosensitive member in a state where the mounting member is mounted; and a transfer unit for transferring the image formed on the electrophotographic photosensitive member onto a recording medium. An image forming apparatus comprising: a conveying unit configured to convey a recording medium. 6. The image forming apparatus according to claim 5, wherein the process cartridge is pressed against the positioning member of the apparatus main body to be positioned by the pressing by the pressing unit. 7. The image forming apparatus according to claim 5, wherein the pressing unit is provided on an opening / closing member that can be opened / closed in the apparatus main body. 8. The pressing means is the longitudinal direction 1 of the second frame body.
Pressing a place, Claim 5 or Claim 6 characterized by the above-mentioned.
The image forming apparatus described. 9. The pressing means comprises a longitudinal direction 2 of the second frame body.
7. The image forming apparatus according to claim 5, wherein the pressure is applied to more than one place. 10. The image forming apparatus according to claim 5, wherein the image forming apparatus is an electrophotographic copying machine, a laser beam printer, or a facsimile machine.