JP3271997B2 - Process cartridge and image forming apparatus - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image forming apparatus such as an electrophotographic copying apparatus, an electrostatic recording apparatus, and a laser beam printer, and a process cartridge detachably mountable on 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 are integrally incorporated into a common housing functioning as a support to form a process cartridge. The process cartridge is detachably mountable to the image forming apparatus main body. 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, the photosensitive drum serving as an image carrier is electrically grounded, and a developing bias is supplied to a developing sleeve serving as a developer carrier. It is necessary that a proper connection be made with the image forming apparatus main body.

FIGS. 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.

[0005] As shown in FIGS. 5 and 6, an end of a photosensitive drum 10 composed of a conductive cylindrical member as a support and a photoconductive layer thereon is provided for driving the photosensitive drum 10. A resin gear flange 104 integrally formed with the gear 104a is fitted.
A ground plate 8 made of a conductive metal having a spring property is attached to the ground. This ground plate 8 has a claw 8
a and 8b are formed, and the pawl portions 8a and 8b are pressed against the inner peripheral wall of the photosensitive drum 10 to establish electrical conduction with the photosensitive drum 10.
A contact portion 8c is formed at the center of the ground plate 8, and the contact portion 8c contacts the end surface of the support shaft 103 of the photosensitive drum 10 by the elastic force of the ground plate 8 itself. still,
The support shaft 103 is provided in a process cartridge (not shown), which is formed of a conductive metal. When the process cartridge is incorporated in the image forming apparatus main body and fixed at 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 the outer peripheral portion thereof. , 210 d, and is fixed by being in contact with the inner peripheral wall of the developing sleeve 112, and is electrically connected to the developing sleeve 112. 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
Reference numeral 11 denotes 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, similarly to the ground contact of the photosensitive drum 10. Power is supplied to this from a developing bias power supply device (not shown) provided on the apparatus main body side.

[0007]

The present invention is a further development of the prior art described above.

[0008]

[0009]

Accordingly, it is an object of the present invention to provide a process cartridge capable of always stably connecting the process means to the image forming apparatus main body side, and an image forming apparatus including the process cartridge. Is to do.

[0011]

SUMMARY OF THE INVENTION In order to achieve the above object, the present invention relates to an image forming apparatus,
In a process cartridge having at least one process unit using a cylindrical member having conductivity and a support unit integrally supporting the process unit, an image is formed when the process cartridge is mounted in an image forming apparatus main body. provided a metal electrode having a spring property that is in direct contact to the fixed forming apparatus main electrodes one each to the respective processing means, said cylinder to press directly the one end face of said cylindrical member with said metal electrodes The shape member is urged in one direction.

Further, according to the present invention, a process cartridge having at least one process means using a conductive cylindrical member and a support means for integrally supporting the process means is attached to and detached from an apparatus main body. In the image forming apparatus, an electrode fixed to the apparatus main body and a metal electrode having a spring property that directly contacts the electrode fixed to the apparatus main body when the electrode is mounted in the apparatus main body are provided for each of the process units. one provided, a mounting portion for mounting detachably a process cartridge comprising biases the cylindrical member in one direction to press the end face directly the cylindrical member with the metal electrodes, the process Guide means for guiding the cartridge to the mounting portion in the apparatus main body.

[0013]

According to the present invention, a process means (for example, an image carrier, a developer carrier, etc.) using a conductive cylindrical member is urged in the thrust direction by an electrode pressed against the end surface thereof. Since the position in the thrust direction is stabilized, the electrical connection of the process means to the image forming apparatus main body side is always stably and surely made.

Further, since the electrode is in direct contact with the cylindrical member and rubs while pressing the cylindrical member , components conventionally required become unnecessary, and the number of components 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 configuration of an electrophotographic copying apparatus as an example of an image forming apparatus according to the present invention will be described with reference to FIG. The cartridge 14 is loaded. In the process cartridge 14, an electrophotographic photosensitive drum 10 serving as an image carrier, and a developing device 11, a charger 12, and a cleaning device 13 arranged around the photosensitive drum 10 are integrally incorporated in a common housing 14a. And is attached to and detached from the apparatus main body 1. The photosensitive drum 10 includes a photoconductive layer and a conductive cylindrical member that supports the photoconductive layer.

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

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

The light image of the document on the document table 25 is radiated onto the photosensitive drum 10 uniformly charged by the charger 12 via 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 to be visualized as a toner image.

On the other hand, the transfer paper P is sent to a registration roller 18 via a paper supply tray 16 and a paper supply roller 17, and is transferred to the transfer section 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 at the transfer section. The transfer paper P to which the toner image has been transferred is sent to the fixing device 20 via the paper ejection guide 19, where the toner image is fixed, and finally the paper ejection roller 2
The paper is discharged out of the apparatus 1 and stacked on the paper discharge tray 22. The residual toner on the photosensitive drum 10 after the transfer is removed by the cleaning device 13 and is prepared for the next image formation.

Here, the photosensitive drum 10 and the developing device 1 incorporated in the process cartridge 14 according to the present invention.
Developing sleeve 11 as developer carrier provided in 1
2 will be described.

The photosensitive drum 10 is formed by forming a photoconductive layer on the surface of a conductive cylindrical member made of aluminum, stainless steel or brass. The photoconductive layer is formed on a rotating shaft 103 attached to 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 integrally with 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 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 is moved at a predetermined speed in the direction of the arrow in FIG. Is driven to rotate.

On the other hand, the developing sleeve 112 is
The toner contained in the photosensitive drum 10
This is made of a cylindrical member made of aluminum alloy or stainless steel, and a magnet roller 115 is provided inside the cylindrical member. The developing sleeve 112 has both ends at bearings 117a and 117.
b, and is rotatably supported by bearings 117a,
Since 117b is urged compression spring 118a, and Tsu by the 118b to the photosensitive drum 10 side, the bearings 117
The developing sleeve 112 supported by a and 117b is also urged in the same direction. For this reason, the ring-shaped gap holding member 1 attached to the outer periphery of both ends of the developing sleeve 112 is used.
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. Further, and gear 119 is mounted et al is on one end of the developing sleeve 112, the gear 119
Meshes with a gear 104 a of the gear flange 104 provided at an end of the photosensitive drum 10. Accordingly, 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 driven to rotate at a predetermined speed in the direction of the arrow in FIG.

On the inner wall of the holder 6, a grounding electrode plate (hereinafter, referred to as a grounding plate) 3 made of a metal such as phosphor bronze having a spring property or stainless steel for a spring, and an electrode for applying a bias voltage (hereinafter, referred to as a biasing electrode). Each of the ground plate 3 and the bias plate 4 presses and rubs the end of the photosensitive drum 10 and the end of the developing sleeve 112, respectively. Here, the photosensitive drum 10 and the developing sleeve 112 are attached with a gap in the thrust direction for smooth rotation of the photosensitive drum 10 and for reasons of assembly accuracy. By urging 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.
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 indicated by the arrow, and the process cartridge 14 is guided along the guide portion 2a for guiding. After being pushed all the way in, the upper cover 2 is closed. Then, when the process cartridge 14 is mounted on the apparatus main body 1, as shown in FIG. 2, the ground plate 3 and the bias plate 4 become elastic earth electrodes 31 and bias electrodes 41 fixed to the apparatus main body 1. , Thereby electrically connecting the photosensitive drum 10 and the developing sleeve 112 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 face of the photosensitive drum 1, the gear flange 104 and the ground plate 8 which were conventionally required as shown in FIGS. In addition, the support shaft 103 and the like become unnecessary, and the number of parts is reduced. If the gear flange is not required, the bonding step of the gear flange is not required for assembly, so that the adhesive does not flow between the ground plate 3 and the photosensitive drum 10 to cause a 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 regardless of the diameter of the photosensitive drum 1, the pressing force can be increased, and the contact between the contact portion and the photosensitive drum 10 can be increased. Good contact is maintained, and the photosensitive drum 10
It is possible to sufficiently cope with a reduction in the diameter of the.

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,
It is possible to reduce the number of parts and eliminate the high-precision assembly process.

Further, similarly to 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. , The stable contact between the two can be realized, and the development sleeve 112 can be sufficiently reduced in diameter.

In addition, since there is no bias plate conventionally used in the developing sleeve 112, the conventional fixing member of the bias plate is not fixed to the developing sleeve 112 and electric noise is generated. The reliability of the device is improved.

In this embodiment, the photosensitive drum 10
As the developing sleeve 112, an aluminum cylinder having a diameter of 12 mm and a thickness of 0.5 mm was used. Further, phosphor bronze was used as the material of the ground plate 3 and the bias plate 4, and the pressing force of the ground plate 3 and the bias plate 4 against 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
Is calculated using the amount of bending of the ground plate 3 and the bias plate 4, the length and width of the free end that undergoes elastic deformation, and the elastic modulus of the material 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, or 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, the image carrier may be a drum-shaped one or an electrophotographic photosensitive belt supported by a plurality of conductive cylindrical members.

[0034]

As is apparent from the above description, according to the present invention, a process means (for example, an image carrier, a developer carrier, etc.) using a conductive cylindrical member is pressed against the end face thereof. Since the electrode is biased in the thrust direction by the electrode and the position in the thrust direction is stabilized, an effect is obtained that the process unit is always stably and reliably electrically connected to the image forming apparatus main body.

Further, according to the present invention, the electrode is in direct contact with the cylindrical member and rubs while pressing the cylindrical member , so that the conventionally required parts are not required, and the number of parts and the cost can be reduced. The effect of being achieved is also obtained.

[Brief description of the 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 to attach a process cartridge according to the present invention to an image forming apparatus main body.

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

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

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

FIG. 7 is a 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 (support means) 31 Earth electrode (device) Electrode on main unit side 41 Electrode for bias (electrode on main unit side) 112 Developing sleeve (developer carrier)

──────────────────────────────────────────────────続 き Continuing on 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 Inside Canon Inc. (72) Inventor Kazuhiko Ishiwata 3-30-2 Shimomaruko, Ota-ku, Tokyo Inside 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 Within Canon Inc. (56) References JP-A-3-265881 (JP, A) JP-A-61-113079 (JP, A) JP-A-1-191166 (JP, A) JP-A-64-24363 (JP, U) JP-A-58-28869 (JP, U) JP-A-61-124062 (JP, U) 105952 (JP, U) (58)査the field (Int.Cl. ^7, DB name) G03G 15/00 550 G03G 21/00 350 - 352 G03G 21/16 - 21/18 G03G 15/06 G03G 15/08

Claims (2)

(57) [Claims] 1. An image forming apparatus comprising: an at least one electrically conductive cylindrical member which is detachably mountable to a main body of the image forming apparatus;
A process cartridge having two process means and a support means for integrally supporting the process means, wherein the process cartridge is in direct contact with an electrode fixed to the image forming apparatus main body when the process cartridge is mounted in the image forming apparatus main body. provided a metal electrode having a spring property by each one for each processing unit, characterized in that biases the cylindrical member in one direction to press the end face directly the cylindrical member with the metal electrodes And process cartridge. 2. An image forming apparatus in which a process cartridge having at least one process means using a cylindrical member having conductivity and a support means integrally supporting the process means is attached to and detached from an apparatus main body. An electrode fixed to the apparatus main body and a metal electrode having a spring property to directly contact the electrode fixed to the apparatus main body when mounted in the apparatus main body are provided one by one for each of the process means. The metal electrode
A mounting portion for mounting detachably a process cartridge comprising biases the cylindrical member in one direction to press the end face directly the cylindrical member, the process cartridge to the mounting portion in the apparatus main body An image forming apparatus comprising: a guide unit for guiding;