JPH05197220A - Process cartridge and image forming device - Google Patents

Abstract

PURPOSE:To always stably and electrically connect a processing means such as an image carrier or a developer carrier to an image forming device-main body side. CONSTITUTION:Since the photosensitive drum (image carrier) 10 and the developing sleeve (developer carrier) 112 are respectively pressed in a thrust direction by an earth plate (electrode) 3 and a bias plate (electrode) 4 which are pressed to the end surfaces of the drum 1 and the sleeve 112, the positions of the thrust directions of the drum 10 and the sleeve 112 are stabilized and they are always stably and electrically connected to the image forming device main body side. Besides, since the earth plate 3 and the bias plate 4 respectively rub the drum 10 and the sleeve 112 while pressing them because they are directly brought into contact with the drum 10 and the sleeve 112, the need of parts which are conventionally required is eliminated and the number of the parts is reduced. Besides, the cost of the device is reduced.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image forming apparatus such as an electrophotographic copying apparatus, an electrostatic recording apparatus, a laser beam printer and the like, and a process cartridge detachably mountable to the main body of the image forming apparatus.

[0002]

2. Description of the Related Art Conventionally, an image forming apparatus includes an image carrier.
Any process means such as a charger, a developing device, and a cleaning device is integrally incorporated into a common housing that functions as a support to form a process cartridge, and the process cartridge is detachable from the main body of the image forming apparatus. Some image forming apparatuses have improved maintainability and serviceability.

By the way, when the process cartridge is incorporated in the main body of the image forming apparatus, electrical connection such as electrical grounding of the photosensitive drum as an image carrier and supply of a developing bias to a developing sleeve as a developer carrier is performed. It is necessary that the physical connection be made with the main body of the image forming apparatus.

5 and 6 show the grounding structure of the photosensitive drum,
7 and 8 show examples of the electrical connection structure of the developing sleeve, respectively.

As shown in FIGS. 5 and 6, at the end portion of the photosensitive drum 10 which is composed of a conductive cylindrical member as a support and a photoconductive layer thereon, the photosensitive drum 10 is driven. A gear flange 104 made of resin, which is integrally formed with the gear 104a, is fitted to the gear flange 104.
A ground plate 8 made of a conductive metal having a spring property is attached to the. The earth plate 8 has a claw portion 8 on its outer peripheral portion.
a and 8b are formed, and the claw portions 8a and 8b are brought into pressure contact with the inner peripheral wall of the photosensitive drum 10 to establish electrical connection with the photosensitive drum 10.
A contact portion 8c is formed at the center of the earth plate 8, and the contact portion 8c is in contact with the end surface of the support shaft 103 of the photosensitive drum 10 by the elastic force of the earth plate 8 itself. still,
The support shaft 103 is disposed in a process cartridge (not shown), which is made of a conductive metal, and when the process cartridge is incorporated in the image forming apparatus main body and fixed in a predetermined position, the support shaft 103 is provided. Is in contact with a contact portion (not shown) on the image forming apparatus main body side.

On the other hand, as shown in FIGS. 7 and 8, a bias plate 210 is provided inside the developing sleeve 112, and the bias plate 210 has claw portions 210a, 210b, 210c formed on its outer peripheral portion. , 210d to be fixed by coming into contact with the inner peripheral wall of the developing sleeve 112, and electrically connected to the developing sleeve 112. In addition, the bias plate 210 has arms 210e, 21
0f is formed, and these arm portions 210e, 210
f is in contact with the electrode plate 211 mounted in the housing 14a of the process cartridge. The electrode plate 2
Similarly to the ground contact of the photosensitive drum 10, 11 is in contact with a developing bias contact portion (not shown) of the image forming apparatus main body when the process cartridge is incorporated in the image forming apparatus main body and fixed at a predetermined position, Power is supplied to this from a developing bias power supply device (not shown) provided on the apparatus main body side.

[0007]

However, in the above-mentioned conventional example, the gear flange 104 in which the ground plate 8 is incorporated.
When the adhesive is adhered to the photosensitive drum 10, excess adhesive may flow into the contact portion of the ground plate 8 to cause defective conduction, so that it is necessary to strictly control the amount of adhesive applied, the drying conditions, and the like. It was

Further, there is a strong market demand for miniaturization of the process cartridge, and since the photosensitive drum 10 is miniaturized, the pressing force of the contact portion 8c of the ground plate 8 cannot be increased, and the contact point is reduced. There is a problem that the contact of the portion 8c with the support shaft 103 tends to be unstable. Further, when the photosensitive drum 10 is driven to move in the thrust direction in the housing 14a by the gap between the housing 14a and the housing 14, the pressing force acting between the ground plate 8 and the support shaft 103 changes.
There is also a problem that contact between the two tends to be unstable.

On the other hand, in the case of the developing sleeve 112, the electrode plates 21 of the arm portions 210e and 210f of the bias plate 210.
In order to keep the pressing force to 1 constant, it was necessary to assemble the bias plate 210 while maintaining the position from the end of the developing sleeve 112 with high accuracy. Further, similarly to the photosensitive drum 10, if the developing sleeve 112 moves in the thrust direction by the gap between the developing sleeve 112 and the housing 14a, the contact state between the bias plate 210 and the electrode plate 211 tends to become unstable. Further, the arm portions 210e, 210 of the bias plate 210 are
Due to the sliding resistance caused by the contact of f with the electrode plate 211, the claw portions 210a, 210b, 210c of the bias plate 210,
There is a case where the engagement of 210d with the developing sleeve 112 becomes weak, and the bias plate 210 does not rotate integrally with the developing sleeve 112. There is also a problem that noise is generated, which causes a malfunction of the main body of the image forming apparatus.

The present invention has been made in view of the above problems, and its object is to provide a process cartridge and a process cartridge which can always stably electrically connect the process means to the main body of the image forming apparatus. An object is to provide an image forming apparatus including a process cartridge.

[0011]

In order to achieve the above object, the present invention integrally provides a plurality of process means including at least one process means using a conductive cylindrical member and the plurality of process means. An electrode having supporting means for supporting and a portion electrically connected to the apparatus main body side when the process cartridge is loaded in the apparatus main body and pressing the end surface of the process means using the conductive cylindrical member. And a process cartridge including the following.

According to the present invention, the process cartridge, the guide means for guiding the process cartridge to a predetermined position in the apparatus main body, and the electrode connected when the process cartridge is in the predetermined position in the apparatus main body. The image forming apparatus is configured to include an electrode on the side of the apparatus main body to be formed.

[0013]

According to the present invention, the process means (for example, the image bearing member, the developer bearing member, etc.) using the conductive cylindrical member is urged in the thrust direction by the electrode pressed against the end face thereof. Since the position in the thrust direction is stable, the electrical connection of the process means to the image forming apparatus main body side is always stable and reliable.

Further, since the electrode is brought into direct contact with the above-mentioned process means and rubs while pressing the process means, the conventionally required parts are not required, so that the number of parts can be reduced and the cost can be reduced.

[0015]

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

First, the structure of an electrophotographic copying machine as an example of the image forming apparatus according to the present invention will be described with reference to FIG. 4, and the process according to the present invention is provided at a substantially central portion in the apparatus main body 1 of the copying apparatus. The cartridge 14 is loaded. The process cartridge 14 integrally includes an electrophotographic photosensitive drum 10 which is an image carrier, a developing device 11, a charger 12 and a cleaning device 13 arranged around the photosensitive drum 10 in a common housing 14a. And is configured as a unit, which is attached to and detached from the apparatus main body 1. The photosensitive drum 10 is composed of a photoconductive layer and a conductive cylindrical member that supports the photoconductive layer.

A transfer charger 15 is disposed below the photosensitive drum 10 of the process cartridge 14 in the apparatus main body 1, and a paper feed tray 16 is provided on the paper feed side of the transfer charger 15. , Paper feed roller 17 and registration roller 1
8, a paper ejection guide 19 and a fixing device 2 are provided on the paper ejection side.
0, a paper discharge roller 21, and a paper discharge tray 22 are provided.

Further, above the process cartridge 14 in the main assembly 1 of the apparatus, an illumination lamp 23 for illuminating the original document and a reflected image light of the original document by the illumination lamp 23 are provided on the photosensitive drum 10.
A short-focus optical element array 24 for exposing the image is provided, and a document table 25 that reciprocates in the direction of arrow A in the figure is provided at the top of the apparatus main body 1.

Thus, the photosensitive drum 10 uniformly charged by the charger 12 is irradiated with the optical image of the original on the original table 25 through the illumination lamp 23 and the short focus optical element array 24. Then, an electrostatic latent image is formed on the photosensitive drum 10, and the electrostatic latent image is developed by the developing device 11 and visualized as a toner image.

On the other hand, the transfer paper P is sent to the registration roller 18 via the paper feed tray 16 and the paper supply roller 17, and is transferred to the transfer portion between the photosensitive drum 10 and the transfer charger 15 at an appropriate timing by the registration roller 18. The toner image formed on the photosensitive drum 10 is transferred and is transferred at this transfer portion. Then, the transfer paper P having the toner image transferred thereto is sent to the fixing device 20 via the paper discharge guide 19, where the toner image is fixed, and finally the paper discharge roller 2
1 is ejected to the outside of the machine and is stacked on the paper ejection tray 22. After the transfer, the residual toner on the photosensitive drum 10 is removed by the cleaning device 13, and the photosensitive drum 10 is prepared for the next image formation.

Here, the photosensitive drum 10 and the developing device 1 built in the process cartridge 14 according to the present invention.
Developing sleeve 11 as a developer carrying member provided in the first embodiment.
The configuration of No. 2 will be described.

The photosensitive drum 10 is constructed by forming a photoconductive layer on the surface of a conductive cylindrical member made of aluminum, stainless steel or brass, which is formed on the rotary spindle 103 mounted on the housing 14a and a part of the holder 6. It is rotatably supported by the formed bearing portion 6a. And
A resin gear flange 104 formed by integrally forming a gear 104a is attached to one end of the photosensitive drum 10, and the gear 104a of the gear flange 104 is provided on the side of the apparatus main body 1 (see FIG. 4). It meshes with the illustrated drive gear. Therefore, when the rotational power from a drive source (not shown) provided on the apparatus main body 1 side is transmitted to the photosensitive drum 10 via the drive gear and the gear flange 104, the photosensitive drum 10 moves at a predetermined speed in the arrow direction of FIG. Is driven to rotate.

On the other hand, the developing sleeve 112 is the developing device 11
The toner contained in the photosensitive drum 10 is carried on the photosensitive drum 10.
It is to be conveyed to the side, and is composed of a cylindrical member made of aluminum alloy or stainless steel, and a magnet roller 115 is provided inside thereof. The developing sleeve 112 has bearings 117a and 117 at both ends.
It is rotatably supported by a bearing 117a,
Since 117b is biased toward the photosensitive drum 10 by the compression springs 118a and 118b, these bearings 117b
The developing sleeve 112 supported by a and 117b is also biased in the same direction. Therefore, the ring-shaped gap holding member 1 attached to the outer circumference of both ends of the developing sleeve 112.
16a and 116b contact the outer surface of the photosensitive drum 10,
As a result, the gap between the developing sleeve 112 and the photosensitive drum 10 is kept constant. A gear 119 is attached to one end of the developing sleeve 112, and the gear 119 is provided on the end portion of the photosensitive drum 10.
No. 04 gear 104a is meshed. Therefore, the rotation of the photosensitive drum 10 is transmitted to the developing sleeve 112 via the gears 104a and 119, and the developing sleeve 112 is rotationally driven at a predetermined speed in the arrow direction of FIG.

By the way, on the inner wall of the holder 6, a ground electrode plate (hereinafter referred to as a ground plate) 3 and a bias voltage application electrode (hereinafter referred to as a bias) made of a metal such as phosphor bronze having a spring property and stainless for spring. 4) is attached, and the respective ends of the ground plate 3 and the bias plate 4 press the end of the photosensitive drum 10 and the end of the developing sleeve 112 to rub against each other. Here, the photosensitive drum 10 and the developing sleeve 112 are mounted with a gap in the thrust direction in order to smooth their rotation and for reasons of assembly accuracy. By biasing the drum 10 and the developing sleeve 112 in one direction, the photosensitive drum 10 and the developing sleeve 112 do not move in the thrust direction, and the photosensitive drum 10 and the developing sleeve 112 do not move.
Therefore, the position of the developing sleeve 112 in the thrust direction does not become unstable.

As shown in FIG. 3, the process cartridge 14 is mounted on the upper cover 2 of the apparatus main body 1 in the direction of the arrow shown in the figure, and the process cartridge 14 is guided along the guide portion 2a for guiding the upper cover. The upper cover 2 is closed after being pushed all the way in. When the process cartridge 14 is attached to the apparatus main body 1, as shown in FIG. 2, the ground plate 3 and the bias plate 4 are fixed to the apparatus main body 1 and have an elastic earth electrode 31 and bias electrode 41. Respectively, so that the photosensitive drum 10 and the developing sleeve 112 are electrically connected to the apparatus main body 1 side.

In the above, since the ground plate 3 as the ground electrode of the photosensitive drum 1 directly presses the end surface of the photosensitive drum 1, the gear flange 104 and the ground plate 8 which have been conventionally required as described in FIGS. 5 and 6 are provided. , The support shaft 103 and the like are unnecessary, and the number of parts is reduced. If the gear flange is unnecessary, the step of adhering the gear flange is not necessary for assembly, and therefore the adhesive does not flow between the ground plate 3 and the photosensitive drum 10 to cause conduction failure.
The reliability of the device is improved.

Further, since the spring contact portion of the ground plate 3 can be made long and thick irrespective of the diameter of the photosensitive drum 1, the pressing force can be increased and the contact portion and the photosensitive drum 10 can be made. Good contact is maintained, and the photosensitive drum 10
It is possible to sufficiently deal with the reduction of the diameter.

On the other hand, also in the developing sleeve 112, since the bias plate 4 directly presses the end surface of the developing sleeve 2, the bias plate 210 (see FIGS. 7 and 8) is mounted in the developing sleeve 112 as in the conventional case. No need to
It is possible to reduce the number of parts and eliminate the highly accurate assembly process.

In addition, like the photosensitive drum 10, the bias plate 4
Since the length and thickness of the spring contact portion can be determined irrespective of the diameter of the developing sleeve 112, the pressing force of the contact portion can be sufficiently increased, and the bias plate 4 causes the developing sleeve 112 to move in the thrust direction. Since it is constantly pressed against the developing sleeve 112, a stable contact between the two can be realized, and the development sleeve 112 can be sufficiently reduced in diameter.

Further, since there is no conventional bias plate in the developing sleeve 112, the conventional problem that the claw portion of the bias plate and the developing sleeve 112 are disengaged and electric noise is generated is solved. The reliability of the device is improved.

In this embodiment, the photosensitive drum 10
An aluminum cylinder having a diameter of 24 mm and a thickness of 0.5 mm was used, and an aluminum cylinder having a diameter of 12 mm and a thickness of 0.5 mm was used as the developing sleeve 112. Phosphor bronze was used as the material of the earth plate 3 and the bias plate 4, and the pressing force of the earth plate 3 and the bias plate 4 on the photosensitive drum 10 and the developing sleeve 112 was 70 to 200 g, preferably 150 to 250 g. Ground plate 3, bias plate 4
The pressing force of is calculated using the bending amount of the ground plate 3 and the bias plate 4, the free end length and width of elastic deformation, and the elastic coefficient of the material itself used.

As the process cartridge, in addition to the one having the photosensitive drum and the developing sleeve integrally,
The cleaning device and the photosensitive drum may be integrated, the charging device, the cleaning device and the photosensitive drum may be integrated, or the charging device and the developing device may be integrated.

On the other hand, as the image bearing member, other than the drum-shaped member, the electrophotographic photosensitive belt may be supported by a plurality of conductive cylindrical members.

[0034]

As is apparent from the above description, according to the present invention, the process means (for example, the image carrier, the developer carrier, etc.) using the conductive cylindrical member is pressed against the end surface thereof. The electrode is urged in the thrust direction by the electrode and the position in the thrust direction is stabilized, so that there is an effect that the electrical connection of the process means to the image forming apparatus main body side is always stable and reliable.

Further, according to the present invention, since the electrode is in direct contact with the above process means and rubs while pressing the process means,
The conventionally required parts are no longer required, and the effects of reducing the number of parts and cost can be obtained.

[Brief description of drawings]

FIG. 1 is a plan sectional view of a process cartridge according to the present invention.

FIG. 2 is a perspective view of a main part of a process cartridge according to the present invention.

FIG. 3 is a perspective view showing how the process cartridge according to the present invention is mounted on the main body of the image forming apparatus.

FIG. 4 is a vertical sectional view of an image forming apparatus (electrophotographic copying apparatus) according to the present invention.

FIG. 5 is a cross-sectional view showing a conventional example of a grounding structure for a photosensitive drum.

FIG. 6 is a partially cutaway perspective view showing a conventional example of a grounding structure of a photosensitive drum.

FIG. 7 is a cross-sectional view showing a conventional example of an electrical connection structure of a developing sleeve.

FIG. 8 is a perspective view of a bias plate showing a conventional example of an electrical connection structure of a developing sleeve.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Image forming apparatus main body 2 Upper cover 2a Guide part (guide means) 3 Ground plate (electrode) 4 Bias plate (electrode) 10 Photosensitive drum (image carrier) 14 Process cartridge 14a Housing (supporting means) 31 Ground electrode (device) Electrode on main body) 41 Electrode for bias (electrode on main body of apparatus) 112 Development sleeve (developer carrier)

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Kazushi Watanabe 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc. (72) Inventor Shinichi Sasaki 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc. (72) Inventor Kazuhiko Ishiwata 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc. (72) Inventor Makoto Tanaka 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc. (72) Inventor Kanji Yano 3-30-2 Shimomaruko, Ota-ku, Tokyo Cannon Inc.

Claims (2)

[Claims] 1. A process cartridge detachable from an apparatus main body, comprising a plurality of process means including at least one process means using a conductive cylindrical member,
Support means for integrally supporting the plurality of process means,
An electrode having a portion electrically connected to the apparatus main body side when the process cartridge is loaded in the apparatus main body and pressing the end surface of the process means using the conductive cylindrical member. Process cartridge characterized by being processed. 2. An image forming apparatus in which a process cartridge is attached to and detached from an apparatus main body, the plurality of process means including at least one process means using a conductive cylindrical member, and the plurality of process means. And an end surface of the process means using the conductive cylindrical member, which has a support means for integrally supporting the process cartridge and a portion electrically connected to the apparatus body side when the process cartridge is loaded in the apparatus body. And a guide means for guiding the process cartridge to a predetermined position in the apparatus main body, and the electrode when the process cartridge is in the predetermined position in the apparatus main body. An image forming apparatus, comprising: an electrode on the apparatus main body side to be combined with the image forming apparatus.