JP2002123062A - Electrifier, processing cartridge and image forming device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide the supporting constitution of an electrifying roller 8 and the driving constitution of the electrifying roller by which a desired intrusion amount is maintained even though a change is caused in the outside diameter of the electrifying roller 8 due to environmental fluctuation in a contact electrifier using the elastic electrifying roller 8 rotated and driven as a contact electrifying member for a body 7 to be electrified. SOLUTION: A specified intrusion amount is obtained by pressing the electrifying roller 8 to the body 7 to be electrified by using an elastic member 104. Also, the rotating/driving means of the electrifying roller 8 possesses a member to be driven 109 attached to the shaft member 8b1 of the electrifying roller 8 and a driving member 110 connected with the member to be driven 109 so as to transmit driving, and has backlash at a connected part between the member to be driven 109 and the driving member 110.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a contact charging device using a rotationally driven elastic charging roller as a contact charging member for an object to be charged, a process cartridge using the contact charging device, and the use of the charging device. The present invention relates to an image forming apparatus capable of attaching or detaching a process cartridge.

[0002]

2. Description of the Related Art Conventionally, in an image forming apparatus such as an electrophotographic apparatus or an electrostatic recording apparatus, an image carrier such as an electrophotographic photosensitive member or an electrostatic recording dielectric as a member to be charged has a required polarity and potential. A corona charger (a corona discharger) has often been used as a charging device for uniformly performing a charging process (including a static elimination process).

[0003] A corona charger is a non-contact type charging device, which includes a discharge electrode such as a wire electrode and a shield electrode surrounding the discharge electrode, and has a discharge opening facing the image carrier as a member to be charged. The surface of the image carrier is charged in a predetermined manner by exposing the surface of the image carrier to a discharge current (corona shower) generated by applying a high voltage to the discharge electrode and the shield electrode.

In recent years, many contact charging devices have been proposed and put into practical use because of their advantages such as low ozone and low power as compared with corona chargers.

[0005] The contact charging device includes a charging member such as a roller type (charging roller), a fur brush type, a magnetic brush type, a blade type, or the like. ) Is contacted, and a predetermined charging bias is applied to the contact charging member to charge the surface of the member to be charged to a predetermined polarity and potential.

[0006] The contact charging mechanism (charging mechanism,
In the charging principle), there are two types of charging mechanisms, a discharge charging mechanism and a direct injection charging mechanism, and each characteristic appears depending on which one is dominant.

The direct injection charging mechanism is a system in which the surface of a member to be charged is charged by injecting charge directly from the contact charging member to the member to be charged. It is also called direct charging, injection charging, or charge injection charging. More specifically, a medium-resistance contact charging member is brought into contact with the surface of the member to be charged, and charges are directly injected into the surface of the member without causing a discharge phenomenon, that is, basically without using discharge. Therefore, even when the voltage applied to the contact charging member is equal to or lower than the discharge threshold, the member to be charged can be charged to a potential corresponding to the applied voltage. Since this charging system does not involve generation of ions, no harm is caused by the discharge products. However, because of direct injection charging, the contact property of the contact charging member to the member to be charged greatly affects the charging property. Therefore, in order to adopt a configuration in which the contact charging member comes into contact with the member to be charged more frequently, the contact charging member has a denser contact point with the member to be charged, and has a large speed difference with the member to be charged. Is required.

As a contact charging device in which a direct injection charging mechanism is dominant, for example, Japanese Patent Application Laid-Open No. 11-109719, 149
196, 149197, 153897, 190927,
In JP-A-190930 and the like, a conductive / elastic charging roller is used as a contact charging member, and a conductive fine powder (charge-promoting particles) for promoting charging is interposed on a contact surface between the charged member and the charging roller. A device having a device configuration in which a charging roller is driven to rotate while maintaining a relative speed difference from a member to be charged is described.

FIGS. 19 and 20 are schematic diagrams of this example of the contact charging device. FIG. 19 is a front model diagram of the main part, FIG. 20A is an enlarged cross-sectional model diagram along the line aa in FIG.
(B) is an explanatory diagram of the amount of intrusion.

Reference numeral 7 denotes a member to be charged, which in this embodiment is a photosensitive drum in an electrophotographic image forming apparatus. The photosensitive drum 7 is rotatably supported between the side plates of the drum frame 102 via a bearing 101. A drum gear 7a is fixed to one end of the photosensitive drum 7. The drum gear 7a is provided with a torsional triangular prism-shaped triangular coupling portion 7a1 and a gear 7a2. The triangular coupling portion 7a1 is provided coaxially with the drum gear 7a, and is a driven transmission portion for receiving drive from an image forming apparatus main body (not shown). The gear 7a2 transmits a driving force to a developing device (not shown). When the triangular coupling portion 7a1 of the drum gear 7a is driven from the image forming apparatus main body side, the photosensitive drum 7 is rotationally driven at a predetermined peripheral speed in a clockwise direction indicated by an arrow in FIG.

Reference numeral 8 denotes a charging roller as a contact charging member. The charging roller 8 has conductivity and elasticity formed concentrically and integrally with the conductive shaft member 8b,
It comprises a contact portion (conductive / elastic roller portion) 8a which comes into contact with the photosensitive drum 7. The axial length of the shaft member 8b is
longer than that of a, protruding from both ends of the contact portion 8a,
It has exposed shaft portions 8b1 and 8b2.

Reference numeral 105 denotes a regulating roller provided coaxially with the contact portion 8a, and is a member for regulating the amount of the charging roller 8 entering the photosensitive drum 7. This regulating roller 105 is provided with shaft portions 8 b 1, 8 on the outer sides of both ends of the contact portion 8 a of the charging roller 8.
It is arranged so as to be freely rotatably fitted to b2. Regulation roller 1
The outer diameter of the charging roller 8 is slightly smaller than the outer diameter of the charging roller 8, for example, about 0.1 to 0.3 mm. The desired intrusion amount regulated by the above can be obtained.

The outer shaft portions 8b1, 8b at both ends of the charging roller 8
2, a charging roller bearing member 103 is attached. The charging roller bearing member 103 has a substantially C-shaped cross section, and the shaft portions 8b1, 8b
Contact 2

Further, the charging roller bearing member 103 includes:
It has an engaging portion (not shown) that engages with a part of the drum frame 102, so that the assembly of the charging roller 8 and the charging roller bearing member 103 can be moved with respect to the photosensitive drum 7. I have.

A compression coil spring 104, which is an elastic member, is mounted between the drum frame 102 and the charging roller bearing member 103. Both ends of the compression coil spring 104 are externally fitted to attachment portions of the charging roller bearing 103 and the drum frame 102. The charging roller 8 is pressed against the photosensitive drum 7 by the compression coil spring 104 so as to make contact therewith. n is a contact nip portion (charging nip portion) between the photosensitive drum 7 and the charging roller 8. The pressing force of the charging roller 8 against the photosensitive drum 7 by the compression coil spring 104 is such that the contact portion 8a, which is a conductive / elastic roller portion, is pressed against the photosensitive drum 7 against its elasticity and compressed, and 105 is a force that keeps the photosensitive drum 7 in contact with the photosensitive drum 7. As shown in FIG. 20B, the amount of compression of the contact portion 8a, which is the conductive and elastic roller portion of the charging roller 8, is the amount of intrusion d. The amount of intrusion d is regulated roller 1.
Regulated at 05.

Reference numeral 106 denotes a charging roller gear, which is attached to the shaft 8b1 of the charging roller 8. The charging roller gear 106 is a driven transmission member for receiving driving for rotating the charging roller 8. The shaft 8b1 of the charging roller 8 is D-cut, while a concave shape is formed at the center of the charging roller gear 106 so as to match the D-cut outer shape of the shaft 8b1, and the charging roller gear 106 is formed on the shaft 8b1 of the charging roller 8. Is installed. The charging roller gear 106 meshes with a drive transmission member (not shown) and is driven to rotate clockwise as indicated by an arrow in FIG. That is, the charging roller 8 is driven to rotate relative to the photosensitive drum 7 while maintaining a desired intrusion amount d and a relative speed difference in the contact nip portion n.

A conductive fine powder is interposed between the outer peripheral surface of the photosensitive drum 7 and the contact portion 8a of the charging roller 8.

In the above-described apparatus configuration, a predetermined charging bias is applied to the charging roller 8 from a charging bias application power supply (not shown), so that the peripheral surface of the photosensitive drum 8 as a member to be charged is directly injected and charged. It is uniformly charged by the mechanism.

[0019]

In the contact charging device as described above, the outer diameter of the charging roller 8, which is a contact charging member, may change due to environmental changes depending on the prescription.

For example, with a charging roller having an outer diameter of 20 mm, high temperature and high humidity (32.5 degrees / 90%) and low temperature and low humidity (15 degrees / 1)
(0%), the change in outer diameter is 0.3 to 0.5 mm.

The penetration amount d of the charging roller 8 is 0.1 to 0.3.
Since this is aimed at mm, this change in outer diameter is a problem that cannot be ignored.

When the outer diameter of the charging roller is reduced, the amount of intrusion d decreases accordingly, that is, the frequency of contact between the charging roller 8 and the photosensitive drum 7 decreases, and as a result, the charging performance cannot be maintained.

Conversely, when the outer diameter of the charging roller 8 increases, the amount of intrusion increases accordingly. When the intrusion amount d increases, the maintenance of the charging performance is not affected at all, but the driving torque required for driving the charging roller 8 and the driving torque of the photosensitive drum 7 increase. Further, as the penetration amount increases, the frequency of contact between the photosensitive drum 7 and the charging roller 8 increases, so that the amount of shaving on the surface of the photosensitive drum 7 also increases.

As described above, when the outer diameter of the charging roller 8 changes due to a change in the use environment, there is a concern that the charging performance is adversely affected, the driving torque increases, and the surface of the photosensitive drum increases.

According to the present invention, there is provided a contact charging device using a rotationally driven elastic charging roller as a contact charging member for an object to be charged, a process cartridge using the contact charging device, and attaching and detaching the charging device or the process cartridge. An object of the present invention is to provide a charging roller supporting structure and a charging roller driving structure that can maintain a desired amount of intrusion even if the outer diameter of the charging roller changes due to environmental fluctuations.

[0026]

According to the present invention, there is provided a charging device, a process cartridge and an image forming apparatus having the following features.

(1) In a charging device in which a charging roller is brought into contact with a member to be charged and the charging roller is driven to rotate to charge the member to be charged, the charging roller includes a shaft member,
An abutting portion integrally formed around the shaft member and having elasticity to come into contact with the member to be charged; the bearing member is rotatably supported by a bearing member; The contact portion is pressed against the member to be charged with a predetermined amount of penetration against its elasticity, and a rotating drive mechanism for the charging roller is attached to the shaft member. A driving member connected to the driven member to transmit driving power to rotate the charging roller, and a connecting portion between the driven member and the driving member has a play. Charging device.

(2) In the charging device described in (1), the driven member is movable in a radial direction of the shaft member in a state where the driven member is attached to the shaft member of the charging roller. Characteristic charging device.

(3) In a charging device in which a charging roller is brought into contact with a member to be charged and the charging roller is driven to rotate to charge the member to be charged, the charging roller includes a shaft member,
An abutting portion integrally formed around the shaft member and having elasticity to come into contact with the member to be charged; the bearing member is rotatably supported by a bearing member; The contact portion is pressed against the member to be charged with a predetermined amount of penetration against its elasticity, and an intermediate portion attached to the shaft member as a rotation driving mechanism of the charging roller. A driving member, wherein the driving member and the intermediate driving member are connected, the intermediate driving member and the driven member are connected, and a rotational driving force is transmitted to the charging roller; and the driving member and the intermediate driving member The first connecting portion and the second connecting portion of the intermediate driving member and the driven member each have a play in the radial direction, and the play directions of the first connecting portion and the second connecting portion are not parallel. A charging device characterized by the above-mentioned.

(4) The charging device according to any one of (1) to (3), wherein the charging roller is driven to rotate while maintaining a relative speed difference with respect to the member to be charged. Charging device.

(5) In the charging device according to any one of (1) to (4), a conductive nip is interposed in a contact nip portion between the charging roller and the member to be charged. Characteristic charging device.

(6) At least a process cartridge which includes an image carrier and a charging device for charging the image carrier, and is detachable from the main body of the image forming apparatus. (5) A process cartridge, which is the charging device according to any one of (5).

(7) An image forming apparatus to which a process cartridge can be attached and detached, wherein the process cartridge includes at least an image carrier and a charging device for charging the image carrier. An image forming apparatus, wherein the charging device for performing the charging process is the charging device according to any one of (1) to (5).

(8) An image forming apparatus for forming an image by an image forming process including a step of charging the image carrier, wherein the charging device for charging the image carrier is any of (1) to (5). An image forming apparatus, which is the charging device according to any one of the above.

<Operation> The first feature of the present invention is as follows.
The amount of intrusion of the charging roller is controlled by a spring pressure management method instead of the roller regulation method, that is, a method of obtaining a predetermined amount of intrusion by urging the charging roller against the member to be charged (image carrier) using an elastic member. It is in the point which did. In this pressure spring management method, an elastic member corresponding to the elastic force (repulsive force) of the contact portion of the charging roller may be employed in order to obtain a desired amount of intrusion. Determined only by accuracy,
Variations can be reduced as compared with the roller regulation system as in the conventional example.

A second characteristic feature is that the driving means of the charging roller has a driven member attached to a shaft member of the charging roller, and a driving member connected to the driven member to transmit driving. The point is that the connection between the driven member and the driving member has a backlash. Since the connecting portion between the driven member and the driving member has a backlash, an external pressing force acting on the charging roller from the driving means toward the member to be charged during the rotation driving state of the charging roller is alleviated. The drive transmission from the drive member to the drive member is possible without substantially affecting the amount of intrusion into the charged body.

According to the first and second features, even when the outer diameter of the charging roller changes due to a change in the use environment,
The amount of intrusion can be kept substantially constant at a predetermined value, and stable charging performance can be maintained.

[0038]

DESCRIPTION OF THE PREFERRED EMBODIMENTS First Embodiment (1) Example of Image Forming Apparatus FIG. 1 is a schematic structural diagram of an image forming apparatus according to the present embodiment. The image forming apparatus of this embodiment is a transfer type electrophotographic process, a cartridge detachable type, a contact charging type, and a cleaner-less laser beam printer.

A is a main body of the image forming apparatus, and B is a process cartridge which is attached to and detached from the main body of the image forming apparatus. Reference numeral 15 denotes an opening / closing member of the image forming apparatus main body A,
Opening / closing operation can be performed centering on 5a. The attachment / detachment of the process cartridge B to / from the image forming apparatus main body A is performed by opening the opening / closing member 15.

Here, the process cartridge is a cartridge in which a charging unit, a developing unit or a cleaning unit and an electrophotographic photosensitive member are integrally formed into a cartridge, and this cartridge is made detachable from an electrophotographic image forming apparatus. . In addition, at least one of the charging unit, the developing unit, and the cleaning unit and the electrophotographic photosensitive member are integrally formed into a cartridge so that the cartridge can be attached to and detached from the electrophotographic image forming apparatus. Further, it means that at least the developing means and the electrophotographic photosensitive member are integrally formed into a cartridge so as to be detachable from the electrophotographic image forming apparatus.

An electrophotographic image forming apparatus forms an image on a recording medium by using an electrophotographic image forming process. For example, an electrophotographic copying machine, an electrophotographic printer (for example, an LED printer, a laser beam printer, etc.) , An electrophotographic facsimile machine, and an electrophotographic word processor.

FIG. 2 is a schematic structural diagram of the process cartridge B in this embodiment. The process cartridge B includes an electrophotographic photosensitive drum 7, a charging roller 8 as a contact charging member, and a developing device (developing means) 10. Reference numeral 28 denotes a drum cover, which is in a closed position where the lower surface of the photosensitive drum 7 is concealed and protected when the process cartridge B is detached from the image forming apparatus main body A (FIG. 2). When the process cartridge B is mounted on the image forming apparatus main body A (FIG. 1), the process cartridge B is in the open position where it has escaped from the lower surface of the photosensitive drum 7, and the transfer between the lower surface of the photosensitive drum 7 and the image forming apparatus main body A side The roller (transfer means) 4 is in contact with the roller.

When the process cartridge B is attached to the image forming apparatus main body A in a predetermined manner, the process cartridge B is brought into a predetermined mechanically and electrically coupled state with the image forming apparatus main body A side.

The image forming operation will be described. The photosensitive drum 7 is driven to rotate clockwise at a predetermined peripheral speed. The rotating photosensitive drum 7 is uniformly charged to a predetermined polarity and potential by a charging roller 8.

The charging roller 8 is disposed in pressure contact with the photosensitive drum 7 with a predetermined penetration amount, and
And rotates while maintaining a relative speed difference at the contact nip n with respect to the photosensitive drum 7. Further, conductive fine powder is interposed between the outer peripheral surface of the photosensitive drum 7 and the contact portion of the charging roller 8. This conductive fine powder is obtained by granulating the primary particles of zinc oxide having a primary particle diameter of 0.1 to 0.3 μm by pressure under pressure and classifying the particles by wind power. In the distribution, 0.5 volume% or less is 35% by volume, and 5 μm or more is 0% by number of fine particle zinc oxide (resistance 1500 Ω · cm, transmittance 35
%)It was used. Then, by applying a predetermined charging bias to the charging roller 8 from a charging bias application power supply (not shown), the peripheral surface of the photosensitive drum 8 is uniformly charged by the direct injection charging mechanism.

A laser scanning exposure of image information by the laser scanner 1 is performed on the charged surface through the exposure opening 9 of the process cartridge B, and a static image corresponding to the image information exposed on the surface of the photosensitive drum 7 is formed. An electrostatic latent image is formed.

The electrostatic latent image is developed by the developing device 10 as a toner image. The developing device 10 includes a rotatable toner feeding member 10b2, which is a toner feeding unit in the toner storage frame 10a, and a toner storage frame 1 through an opening 10g of the toner storage frame and an opening 10h of the toner development frame 10f.
0f, and sends the toner to the toner stirring member 10b.
1, the developing roller 10d, which is a developing rotator including a fixed magnet 10c, is rotated, and a toner layer provided with a triboelectric charge by a developing blade 10e is formed on the surface of the developing roller 10d. By transferring the toner image to the photosensitive drum 7 in accordance with the latent image, a toner image is formed and a visible image is formed.

On the other hand, in synchronism with the formation of the toner image, the recording medium 2 is separated and fed one by one from the paper feed cassette 3a accommodating the recording medium 2 by the pickup roller 3b and the pressing member 3c pressed against the same. The recording medium 2 is conveyed at a predetermined control timing to a transfer nip portion, which is a contact portion between the photosensitive drum 7 and the transfer roller 4, by a conveying means 3 including a pair of conveying rollers 3d and a pair of registration rollers 3e. .

By applying a predetermined transfer voltage having a polarity opposite to that of the toner image to the transfer roller 4, the toner image on the surface of the photosensitive drum 7 is sequentially transferred to the recording medium 2 fed to the transfer nip portion. Is done.

The recording medium 2 that has passed through the transfer nip is separated from the surface of the photosensitive drum 7 and is conveyed to the fixing means 5 by the conveying belt 3f, and the toner image on the recording medium 2 is fixed by heat and pressure. You. The fixing means 5 is disclosed in, for example,
No. 44075 discloses a heating and fixing device of a film heating type and a pressure roller driving type.

The recording medium 2 on which the toner image is fixed is conveyed by a pair of discharge rollers 3g and 3h, and is discharged to the face-down discharge section 6 through a reverse conveyance path.

Reference numeral 3i denotes a manual feed tray stored in the main body of the image forming apparatus, which is opened in a predetermined state at the time of manual feed, and can be manually fed by the tray 3i and the feed roller 3j.

Reference numeral 6a denotes a face-up discharge unit which is stored in the image forming apparatus main body. When the face-up discharge is performed, the discharge unit 6a is opened in a predetermined state so that face-up discharge is possible.

The image forming apparatus of this embodiment is cleaner-less, and the transfer residual toner on the surface of the photosensitive drum 7 after the transfer of the toner image onto the recording medium 2 is not removed by a dedicated cleaning device. As the drum 7 rotates, it is carried to the developing unit and is subjected to “simultaneous development cleaning” by the developing device 10.

That is, in a normal transfer type electrophotographic image forming apparatus, the transfer residual toner remaining on the photosensitive drum after transfer is removed from the photosensitive member surface by a cleaning device to become waste toner. It is desirable not to come out from the viewpoint of environmental protection. Therefore, the toner recycling system (or toner) is configured so that the cleaning device is eliminated, and the transfer residual toner on the photoconductor drum after transfer is removed from the photoconductor drum by the developing device at the same time as the development cleaning, and is collected and reused in the developing device. Recycling process) is effective.

Simultaneous development and cleaning means that the toner remaining on the photoreceptor after transfer is developed during the next and subsequent steps, that is, the photoreceptor is subsequently charged and exposed to form a latent image. This is a method of recovering by a picking bias (fogging potential difference Vback which is a potential difference between a DC voltage applied to the developing device and a surface potential of the photoconductor). According to this method, the transfer residual toner is collected in the developing device and reused after the next process. Therefore, waste toner can be eliminated and troublesome maintenance can be reduced. Also, because it is cleaner-less, there are great advantages in terms of space,
The size of the image recording apparatus can be greatly reduced.

In the process cartridge B of this embodiment, each member such as the photosensitive drum 7 is
toner storage frame 1 supporting rotatably driven b2
0a, the toner stirring member 10b1, the developing roller 10d,
A developing unit D in which a developing member such as a developing blade 10e is incorporated and a developing unit D in which a lid member 10i is welded and integrated, and a drum frame 102 having a photosensitive drum 7 and a charging roller 8 are connected. The cartridge is housed in a cartridge frame configured as described above, is formed into a cartridge, and is detachably mounted on a cartridge mounting means provided in the image forming apparatus main body A.

(2) Method for Controlling Penetration Amount of Charging Roller 8 and Method of Driving A) Method for Controlling Penetration Amount of Charging Roller (Charging Roller Support Structure) FIG. 3 is a front model diagram of the charging roller 8 disposed in the cartridge B. is there.

The photosensitive drum 7 is rotatably mounted on a drum frame 102 including the photosensitive drum 7 and the charging roller 8 via a drum bearing 101 and a side holder 107. A drum gear 7a fixed to one end of the photosensitive drum 7 is provided with a torsional triangular prism-shaped triangular coupling part 7a1, a first gear part 7a2, and a second gear part 7a3. The triangular coupling portion 7a1 is provided coaxially with the drum gear 7a, and the image forming apparatus main body A
This is a driven transmission section for receiving driving from the side. The first gear portion 7a2 is a gear for transmitting a driving force to the developing device 10 side. The second gear portion 7a3 is a gear for transmitting drive to the charging roller 8.

The charging roller 8 serving as a contact charging member is formed of a conductive shaft member 8b and a concentrically integrated part around the conductive shaft member 8b. (Conductive / elastic roller). Shaft member 8b
Of the contact portion 8a is longer than that of the contact portion 8a.
The shaft portions 8b1 and 8b protruding from both ends of
Two.

Outer shaft portions 8b1, 8b at both ends of the charging roller 8
2, a charging roller bearing member 103 is attached. The charging roller bearing member 103 has a substantially C-shaped cross section, and the shaft portions 8b1, 8b
Contact 2

Further, the charging roller bearing member 103 is
It has an engaging portion (not shown) that engages with a part of the drum frame 102, so that the assembly of the charging roller 8 and the charging roller bearing member 103 can be moved with respect to the photosensitive drum 7. I have.

A compression coil spring 104, which is an elastic member, is mounted between the drum frame 102 and the charging roller bearing member 103. Both ends of the compression coil spring 104 are externally fitted to attachment portions of the charging roller bearing 103 and the drum frame 102. The compression coil spring 104 causes the charging roller 8 to contact the photosensitive drum 7 with the contact portion 8a.
Are pressed against each other to form a pressure-contact nip portion (charging nip portion) n.

Specifically, the amount of intrusion of the charging roller 8 is set to 0.
Working load is 4.9N (500gf) to keep at 2mm
And two compression coil springs 104 were used. The compression coil spring 104 has a spring constant with a compression amount of about 3 mm.

In the present embodiment, a method of controlling the amount of intrusion of the charging roller 8 by using only the pressing force of the compression coil spring 104 is employed. In this pressure spring method, a compression coil spring corresponding to the elastic force (repulsion force) of the contact portion of the charging roller 8 may be employed in order to obtain a desired penetration amount.・ Depending on the mounting accuracy only,
Variations can be reduced as compared with the regulation roller 105 (regulation roller method in FIGS. 19 and 20) as in the conventional example.

According to the calculation made by the present inventor, it has been found that the variation in the spring pressure method is less than half of that in the regulation roller method.

Charging roller 8 depending on use environment
The case where the outer diameter change occurs will be described.

It is assumed that the outer diameter of the charging roller 8 increases. Assuming that the outer diameter change amount is 0.5 mm of Max, the compression coil spring 104 is reduced by 0.25 mm, which is half of the outer diameter change amount. The compression coil spring 104 is compressed by 3 mm to obtain a penetration amount of 0.2 mm.
In the case of m, the amount of increase of the penetration amount was about 0.017 mm, which was a level having no influence.

Conversely, the same applies to the case where the outer diameter of the charging roller 8 is reduced. The reduction in the penetration amount is 0.017 mm with respect to the outer diameter change amount of 0.5 mm, which is a level having no effect.

As described above, by controlling the intrusion amount by the spring pressure management system instead of the roller regulation system, the intrusion amount can be kept constant even when the outer diameter of the charging roller changes due to a change in the use environment. And charging performance can be maintained.

In the present invention, the amount of penetration of the charging roller 8 is controlled by a method of controlling only the pressing force of the compression coil spring 104 (spring pressurization method).

B) Charging Roller Driving Configuration Spring Pressing Method + Conventional Driving Structure Before describing the charging roller driving structure according to the present invention, first, a spring pressing method is adopted in the conventional example (FIGS. 19 and 20), that is, when the regulating roller 105 is eliminated. The description is given with reference to FIG.

FIG. 4 is a diagram showing a driving gear train for driving the charging roller 8 as viewed from the axial direction. The charging roller 8 is driven to rotate the charging roller gear 106 via the idler gear 108 from the drum gear 7a. The idler gear 108 is a two-stage gear having two gear portions, and is rotatably supported. The rotation direction of each gear is H
Direction. The charging roller 8 and the photosensitive drum 7 rotate in the same direction, and rub against each other at a contact portion (charging nip portion) n.

The charging roller gear 106 is the idler gear 10
8 receives an external force in the K direction. Then, since the regulating roller 105 is not attached to the charging roller 8, the charging roller 8 is pressed toward the photosensitive drum 7. J
Is the charging roller movable direction. The pressing force at this time is 9.
8N (1 kgf) or less.
Is applied to the charging roller 8 and the amount of intrusion increases.

Therefore, it is necessary to change the drive configuration of the charging roller 8.

. Driving Configuration of Charging Roller According to the Present Example Next, the driving configuration of the charging roller according to the present exemplary embodiment will be described with reference to FIGS. FIG. 5 is a perspective view of a drum gear portion, FIG. 6 is an exploded perspective view of a charging roller driving component, and FIG. 7 is a perspective view of a joint gear.

A joint 109 as a driven transmission member for receiving driving for rotating the charging roller 8 is attached to the shaft portion 8b1 of the charging roller 8. Attachment of the joint 109 to the shaft portion 8b1 of the charging roller 8 is performed by forming a concave shape at the center of the joint 109 so as to conform to the two-sided outer shape of the shaft portion 8b1 of the charging roller 8, and attaching the concave portion to the shaft portion. 8b1 by fitting it to the two-way outer shape.

The joint 109 has a substantially flat joint connecting portion 109a. This joint connecting portion 109
“a” is connected to the joint gear connecting portion 110a of the joint gear 110 to transmit the drive. The joint gear 110 includes a joint gear connecting portion 110a and a joint gear portion 110b. The joint gear connecting portion 110a is a columnar projection, and has two positions symmetrical with respect to the rotation axis. Also, the coupling gear portion 110b transmits the meshing drive with the idler gear 111. The joint gear 110 has a through hole formed in parallel with the rotation center axis, and is rotatably supported on the axis of the side holder 107.

The idler gear 111 is a two-stage gear having two gear portions, and is rotatably supported on a shaft of the side holder 107. The two gear portions of the idler gear 111 transmit meshing drive with the joint gear portion 110b and the second gear portion 7a3 of the drum gear 7a, respectively.

The second gear portion 7a3 of the drum gear 7a is a gear portion for driving the charging roller 8. In the present embodiment, the first gear portion 7a2 and the second gear portion 7a3 are separate. One gear may serve as one gear.

FIG. 8 shows a state of the joint between the joint 109 and the joint gear 110. The joint gear 110 is connected to the joint gear connecting portion 11.
Only 0a is shown. The joint gear 110 rotates in the direction of the arrow in the figure. The joint gear connecting portion 110a idles between the dashed line and the solid line in the drawing, that is, has a "lash", and comes into contact with the joint connecting portion 109a at the position of the solid line. When contact starts, the joint gear connecting portion 110a and the joint connecting portion 109a rotate in conjunction with each other.

[0082] When Outer Diameter Change of Charging Roller 8 Occurs Due to Usage Environment The situation when the outer diameter of charging roller 8 changes due to the usage environment will be described with reference to FIG. In FIG. 9, as in FIG. 8, only the joint gear 110 is shown for the joint gear 110. As a condition, the outer diameter of the charging roller 8 is increased and the joint 1 at that time is increased.
It is assumed that a shift (shift L) between the center of the joint gear 110 and the center of the joint gear 110 has occurred. From the contact position in FIG. 8, the charging roller 8 (joint 1
09) shows a connection state between the joint 109 and the joint gear connecting portion 110a when the joint 109 and the joint gear connecting portion 110a are driven to rotate 180 degrees by 30 degrees.

The movable direction position of the rotation center of the charging roller 8 is indicated by CL. The radial direction of the external force received by the joint 109 is represented by F. The photosensitive drum 7 (not shown) is a joint 1
09 directly below.

A. At the rotation angles of 0 degree and 180 degrees, the joint connecting portion 109a can be driven by the two joint gear connecting portions 110a.

B. In the range from more than 0 degrees to less than 180 degrees, the joint connecting portion 109a is a single joint gear connecting portion 110a.
To receive an external force in the direction F in FIG.

C. In order to return to the same state as 0 degree at 180 degrees, the cycle of FIG. 9 is repeated twice during one rotation of the charging roller 8 by repeating from 0 degrees to 180 degrees from 180 degrees to 360 degrees.

The charging roller 8 is periodically pressed against the photosensitive drum (not shown, located in the lower part of the drawing) by this external force. In this embodiment, the external force is always applied in a fixed direction, but in this embodiment, the pressing force is a periodic pressing force. The amount of increase in drive torque is also small.

The case where the outer diameter of the charging roller 8 is large has been described on the premise of FIG. 9. Conversely, when the outer diameter is small, the charging roller 8 is exposed to the photosensitive drum (not shown, Position), but because it is a periodic external force, its effect is less than in the "spring pressurization method + conventional drive configuration", and the intrusion amount change and drive A small increase in torque is required.

Thus, the charging roller supporting structure and the charging roller driving structure of the first embodiment can stabilize the amount of intrusion compared to the conventional structure even if the outer diameter of the charging roller changes due to environmental changes of the charging roller. Can be maintained.

<< Second Embodiment >> A detailed description of the second embodiment will be described with reference to FIG. 3 and FIGS.

A) Charging Roller Penetration Limiting Method (Charge Roller Supporting Structure) The spring pressure regulating method is adopted as in the first embodiment, as in the first embodiment.

B) Charging Roller Driving Configuration This embodiment is different from the first embodiment only in the relationship between the mounting hole of the joint 109 to the shaft 8b1 of the charging roller 8 and the two-way cutting of the shaft 8b1 of the charging roller 8 in the first embodiment. Therefore, the description of the components other than the joint 109 will not be repeated. The assembled state of this embodiment is the same as FIG.

FIG. 10 is a schematic diagram for explaining the dimensional relationship between the two-sided portion of the charging roller shaft portion 8b1 and the joint 109. At the center of the joint 109, there is a mounting hole 109b to be attached to a two-way portion of the shaft 8b1 of the charging roller 8. Fitting 10
The hole width M2 of the nine mounting holes 109b has a dimensional relationship that just fits the two-way width M1 of the shaft portion 8b1. The hole length N2 of the mounting hole 109b of the joint 109 is longer than the length N1 of the two-way portion of the shaft portion 8b1 (the shaft diameter of the shaft portion 8b1). Therefore, the joint 109 is connected to the charging roller 8.
When attached to the shaft portion 8b1, the joint 109 has a play in a direction parallel to the two-way flat surface portion, and is slidable, that is, has "play".

The arrangement of the mounting holes 109b is considered so that the sliding direction is not parallel to the joint connecting portion 109a, preferably approximately 90 degrees.

FIG. 11 shows the state of the connection between the joint 109 and the joint gear 110. The joint gear 110 is a joint gear connecting portion 1
Only 10a is shown. In addition, a two-way portion of the shaft portion 8b1 is indicated by oblique lines. The joint gear 110 rotates in the direction of the arrow in the figure. The joint gear connecting portion 110a idles between the broken line and the solid line in the drawing, that is, has a backlash, and comes into contact with the joint connecting portion 109a at the position of the solid line. When contact starts, the joint gear connecting portion 110a and the joint connecting portion 109a rotate in conjunction with each other.

The situation when the outer diameter of the charging roller 8 changes due to the use environment will be described with reference to FIG. In FIG. 12, FIG.
Like FIG. 1, only the joint 109, the joint gear connecting portion 110a, and the two-way portion (hatched portion) of the shaft portion 8b1 are shown. As a condition, the outer diameter of the charging roller 8 is increased, and the joint 10 at that time is increased.
It is assumed that a shift (shift L) between the center of the joint gear 9 and the joint gear 110 has occurred. From the contact position shown in FIG.
09) shows a connection state between the joint 109 and the joint gear connecting portion 110a when the joint 109 and the joint gear connecting portion 110a are driven to rotate by 180 degrees by 30 degrees.
The position in the movable direction of the rotation center of the charging roller is indicated by CL.

It can be seen that the two joint gear connecting portions 110a and 109a are driven while being in contact with each other through a rotation angle of 0 to 180 degrees.

As a result, the driving force from the joint gear connecting portion 110a to the joint connecting portion 109a is only a couple force. Further, the driving force from the joint 109 to the shaft portion 8b1 is also due to the abutment on the two-way chamfered surface. Only power.

That is, only the driving force in the rotational direction is transmitted to the charging roller 8, and the driving transmission without affecting the amount of intrusion into the photosensitive drum 7 becomes possible.

This is because the joint 109 has a backlash in a direction parallel to the two-way flat portion and is slidable in that direction, ie, has a backlash, so that the two joint gear connection portions 110 are always present.
This is because the a and the joint connecting portion 109a can rotate while abutting.

Although the case where the outer diameter of the charging roller 8 is large has been described as a premise of FIG. 12, the two joint gear connecting portions 110a and the connecting portion
Since the roller 9a rotates while being in contact with the charging roller 8, only the driving force in the rotational direction is transmitted to the charging roller 8, and the driving transmission without affecting the amount of intrusion into the photosensitive drum 7 becomes possible.

Therefore, even with the charging roller supporting structure and the charging roller driving structure of the second embodiment, the amount of intrusion can be stably maintained even if the outer diameter of the charging roller changes due to the environmental change of the charging roller. it can.

<< Third Embodiment >> A detailed description of the third embodiment will be described with reference to FIGS.

A) Charge Roller Penetration Limiting Method (Charge Roller Support Structure) The spring pressure regulating method is employed as in the first embodiment, as in the first embodiment.

B) Charging Roller Driving Configuration The third embodiment differs from the first and second embodiments only in the connection portion from the joint gear 110 to the joint 109. The description will not be repeated.

FIG. 13 is a schematic structural view for explaining an assembled state of this embodiment. 14, 15 and 16 are perspective views illustrating the drive components.

A joint 109 as a driven transmission member for receiving driving for rotating the charging roller 8 is attached to the shaft portion 8b1 of the charging roller 8. Fitting 109
A joint 109 is attached to the center of the charging roller 8 so as to form a concave shape that matches the two-sided outer shape of the shaft portion 8b1 of the charging roller 8.
The joint 109 has a joint connecting portion 109c formed of a columnar projection, which is formed symmetrically with respect to the central axis. The joint connecting portion 109c is connected to the intermediate joint second connecting portion 112b of the intermediate joint 112 and is driven.

The joint gear 110 has a joint gear connecting portion 110a.
And a joint gear portion 110b. Joint gear connecting part 110
a is a columnar projection, and there are two locations symmetrical with respect to the rotation axis. Also, the coupling gear portion 110b transmits the meshing drive with the idler gear 111. The joint gear 110 has a through hole formed in parallel with the rotation center axis, and is rotatably supported on the axis of the side holder 107. Joint gear 110 is intermediate joint 1
Twelve intermediate joints are connected to the first connecting portion 112a to transmit the drive.

The intermediate joint 112 includes the joint 109 and the joint gear 1
10 so as to be sandwiched therebetween. A joint connecting portion 109c fits on a surface facing the joint 109, a long hole-shaped intermediate joint second connecting portion 112b to be connected and a joint gear connecting portion 110a fits on a surface facing the joint gear 110, An intermediate joint first connection portion 112a having a long hole shape with an open outer end to be connected is formed.

The elongated holes of the intermediate joint first connecting portion 112a are arranged at two locations symmetrical with respect to the rotation axis, and similarly, the elongated holes at one end of the intermediate joint second connecting portion 112b are arranged at two locations symmetrically with respect to the rotation axis.

The angle formed by the first joint 112a of the intermediate joint and the second joint 112b of the intermediate joint is set at an angle other than parallel, preferably at a right angle.

In a state where the intermediate joint 112 is connected to the joint gear 110 (a protrusion is fitted in the hole), the intermediate joint 112 is elongated in the elongated hole direction because the intermediate joint first connecting portion 112a has a long hole shape. It is slideable.

In the state where the intermediate joint 112 is connected to the joint 109 (the protrusion is fitted in the hole), the intermediate joint
Since the connecting portion 112b has an elongated hole shape, the intermediate joint 112
Has a play in the direction of the long hole and can slide.

FIG. 16 shows a joint gear 110 and an intermediate joint 112.
FIG. 5 is a cross-sectional view illustrating a connection state between the and the joint 109. The joint gear 110 has only the joint gear connecting portion 110a, and the joint 109
Shows only the joint connecting portion 109c. Note that the joint gear connecting portion 110a is hatched in order to distinguish between the joint gear connecting portion 110a and the joint connecting portion 109c.

The situation when the outer diameter of the charging roller 8 changes due to the use environment will be described with reference to FIG. In FIG. 17, FIG.
Similarly, the joint gear 110, the intermediate joint 112, and the joint 10
9 is a cross-sectional view showing a connection state of the coupling gear connection portion 11;
In order to distinguish between Oa and the joint connecting portion 109c, the joint gear connecting portion 110a is hatched. Coupling gear 110
Shows only the joint gear connecting portion 110a, and the joint 109 shows only the joint connecting portion 109c. As a condition, it is assumed that the outer diameter of the charging roller 8 increases, and a shift (shift amount L) between the center of the joint 109 and the center of the joint gear 110 at that time occurs. From the contact position shown in FIG.
The coupling state of the coupling 109 and the coupling gear coupling portion 110a when driven to rotate by 80 degrees is shown. The movable direction position of the rotation center of the charging roller is indicated by CL. The photoconductor drum 7 (not shown) is located immediately below the joint 109.

In order to return to the same state as 0 ° at 180 °, it is convenient to repeat from 0 ° to 180 ° from 180 ° to 360 °, so that the cycle of FIG. 10 is repeated twice while the charging roller 8 makes one rotation. Becomes

Through the rotation angle of 0 to 180 degrees, the joint gear connecting portion 110a and the intermediate joint first connecting portion 112a abut at two places, and the intermediate joint second connecting portion 112b and the joint connecting portion 109c also abut at two places. In contact.

As a result, the driving force from the joint gear connecting portion 110a to the intermediate joint 112 is only a couple. Further, the driving force from the intermediate joint 112 to the joint 109 (the shaft portion 8b1) is only a couple.

Accordingly, only the driving force in the rotation direction is transmitted to the charging roller 8, and the driving transmission without affecting the amount of intrusion into the photosensitive drum 7 can be performed.

This is because the intermediate joint 112 is
9c and the joint gear connecting portion 110a have a play and can slide in this direction.
This is because abutment between the a and the intermediate joint first connection portion 112a and abutment between the intermediate joint second connection portion 112b and the joint connection portion 109c can be performed while maintaining two positions.

Although the case where the outer diameter of the charging roller 8 is large has been described as a premise of FIG. 17, similarly, when the outer diameter is small, similarly, the joint gear connecting portion 110a and the intermediate joint first connecting portion 112a are always two. At the point, and the intermediate joint second connecting portion 1
Since the joint 12b and the joint connecting portion 109c also rotate while abutting at two places, only the driving force in the rotational direction is transmitted to the charging roller 8, so that the driving transmission without affecting the amount of intrusion into the photosensitive drum 7 becomes possible. .

Therefore, even with the charging roller supporting structure and the charging roller driving structure of the third embodiment, the amount of intrusion can be stably maintained even if the outer diameter of the charging roller changes due to the environmental change of the charging roller. .

<< Other Embodiments >> 1) In the first to third embodiments, the driving force for driving the charging roller 8 is branched from the drum gear 7a inside the process cartridge. Alternatively, the driving may be branched from the image forming apparatus main body. For example, as shown in FIG.
A configuration may be adopted in which a joint portion 113 which is a driving member for driving the charging roller 8 is attached to the image forming apparatus main body and connected to the joint 109.

2) Various developing methods such as a known two-component magnetic brush developing method, cascade developing method, touch-down developing method, and cloud developing method can be used as the developing method.

3) The electrophotographic photosensitive member is not limited to the above-mentioned photosensitive drum, and includes, for example, the following. First, a photoconductor is used as the photosensitive member. Amorphous silicon, amorphous selenium, zinc oxide, titanium oxide and organic photoconductor (O
PC) and the like.

The shape for mounting the photoconductor is as follows.
For example, a rotating body such as a drum shape and a belt shape, and a sheet shape are included. In general, a drum-shaped or belt-shaped one is used. For example, in the case of a drum type photoreceptor, a photoconductor is deposited or coated on a cylinder of aluminum alloy or the like. It is.

In the case of an electrostatic recording device, the image carrier as the member to be charged is an electrostatic recording dielectric.

4) As a material for forming the toner storage frame 10a and the toner development frame 10f, plastic such as polystyrene, ABS resin (acrylonitrile / butadiene / styrene copolymer), modified PPE resin (polyphenylene ether), and modified PPO Resin (polyphenylene oxide), polycarbonate, polyethylene, polypropylene and the like.

5) In the above embodiment, a laser beam printer was exemplified as an image forming apparatus. However, the present invention is not limited to this. For example, an electrophotographic copying machine, a facsimile machine, a word processor, or the like may be used. Of course, it can be used for other image forming apparatuses.

6) The charging device of the present invention is not limited to the image bearing member (electrophotographic photosensitive member, electrostatic recording dielectric, etc.) of the image forming apparatus, but is widely used as a charging means (including a static elimination process) for an object to be charged. Effective to use.

[0131]

As described above, according to the present invention, a contact charging device using a rotationally driven elastic charging roller as a contact charging member for a member to be charged, a process cartridge using the contact charging device, and Regarding the image forming apparatus using the charging device or the detachable process cartridge, even if the outer diameter of the charging roller changes due to the environmental change of the charging roller, the charging roller is driven while maintaining a desired intrusion amount. be able to.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram of an image forming apparatus according to a first embodiment.

FIG. 2 is a schematic cross-sectional view of a process cartridge.

FIG. 3 is a schematic front view of a charging roller portion.

FIG. 4 is a diagram of a gear train in a spring pressurization type + conventional drive configuration.

FIG. 5 is a perspective view of a drum gear portion.

FIG. 6 is an exploded perspective view of a charging roller driving component.

FIG. 7 is a perspective view of a coupling gear.

FIG. 8 is a schematic diagram illustrating a connection state of a drive configuration.

FIG. 9 is a schematic diagram illustrating a connection state during driving of the drive connection unit when the outer diameter of the charging roller changes.

FIG. 10 is a schematic diagram illustrating a dimensional relationship between a two-way portion of a charging roller shaft and a joint in the charging roller driving configuration according to the second embodiment.

FIG. 11 is a schematic diagram illustrating a connection state of a drive configuration.

FIG. 12 is a schematic diagram illustrating a connection state during driving of the drive connection unit when the outer diameter of the charging roller changes.

FIG. 13 is a schematic diagram illustrating a configuration of a charging device according to a third embodiment.

FIG. 14 is an exploded perspective view of a charging roller driving component.

FIG. 15 is an exploded perspective view of a joint gear and an intermediate joint.

FIG. 16 is a schematic diagram illustrating a connection state of a drive configuration.

FIG. 17 is a schematic diagram illustrating a connection state during driving of the drive connection unit when the outer diameter of the charging roller changes.

FIG. 18 is a schematic diagram illustrating a configuration of a charging device according to another embodiment.

FIG. 19 is a schematic view illustrating the configuration of a conventional charging device.

FIG. 20 is an explanatory diagram of the amount of intrusion between the charging nip portion and the charging roller.

[Explanation of symbols]

A: Image forming apparatus B: Process cartridge F: External force direction H: Driving gear rotating direction J: Charging roller movable direction K: Meshing direction L: Displacement amount N1: Length of two-sided portion, N2: Hole length M1: 2 Measuring width, M2: Hole width 1: Optical system (laser scanner) 2: Recording medium 3: Conveying means, 3a: Paper cassette, 3b: Pickup roller, 3c: Press-contact member, 3d: Conveying roller, 3e ...
Registration rollers, 3f: Conveying belt, 3g, 3h: Discharge roller, 3i: Manual tray, 3j: Manual roller 4, Transfer roller 5, Fixing means 6, Discharge unit 7, Photoconductor drum, 7a, Drum gear, 7a1 Triangular coupling, 7a2 first gear portion, 7a3 second gear portion 8, charging roller, 8a contact portion, 8b shaft member, 8b1
... Shaft 9 ... Exposure opening 10 ... Developing means, 10a ... Toner storage frame, 10b1 ...
Toner agitating member, 10b2 ... Toner sending member, 10c ...
Fixed magnet, 10d developing roller, 10e developing blade, 10f toner developing frame, 10g toner storing frame opening, 10h toner developing frame opening, 10i lid member 101 drum bearing 102 drum frame Body 103: Charging roller bearing member 104: Compression coil spring 105: Control roller 106: Charging roller gear 107: Side holder 108: Idler gear 109: Joint, 109a: Joint connecting part, 109b: Mounting hole, 109c: Joint connecting part 110: Joint Gear, 110a ... joint gear connecting portion, 110
b: coupling gear portion 111: idler gear 112: intermediate coupling, 112a: intermediate coupling first connecting portion, 1
12b: Intermediate joint second connecting part 113: Joint part

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Masaya Morioka 3-30-2 Shimomaruko, Ota-ku, Tokyo Inside Canon Inc. (72) Inventor Takashi Akutsu 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon F term in the company (reference) 2H003 BB11 CC05 EE16 2H071 BA04 BA43 CA05 DA06 DA26 3J103 AA02 AA13 CA25 FA16 FA26 FA30 GA02 GA52 HA03 HA12

Claims (8)

[Claims] 1. A charging roller is brought into contact with an object to be charged,
In a charging device for charging a member to be charged by rotating the charging roller, the charging roller has a shaft member and an elastic member integrally formed around the shaft member and having elasticity to come into contact with the member to be charged. A contact portion, the shaft member is rotatably held by a bearing member, and the elastic member presses in the direction of the member to be charged, and the contact portion has a predetermined penetration amount against its elasticity. A driven member attached to the shaft member as a rotation driving mechanism for the charging roller, and a driving member connected to the driven member to transmit drive to rotate the charging roller. A charging member having a driving member, and a connecting portion between the driven member and the driving member. 2. The charging device according to claim 1, wherein the driven member is movable in a radial direction of the shaft member while being attached to the shaft member of the charging roller. Charging device. 3. A charging roller is brought into contact with a member to be charged,
In a charging device for charging a member to be charged by rotating the charging roller, the charging roller has a shaft member and an elastic member integrally formed around the shaft member and having elasticity to come into contact with the member to be charged. A contact portion, the shaft member is rotatably held by a bearing member, and the elastic member presses in the direction of the member to be charged, and the contact portion has a predetermined penetration amount against its elasticity. An intermediate drive member attached to the shaft member as a rotation drive mechanism of the charging roller, wherein the drive member and the intermediate drive member are connected to each other; And the driven member are connected to each other, and the rotational driving force is transmitted to the charging roller. The first connecting portion between the driving member and the intermediate driving member and the second connecting portion between the intermediate driving member and the driven member are respectively provided. Radially It has other, charging device backlash direction of the second connection part and the first connecting portion and wherein the non-parallel. 4. The charging device according to claim 1, wherein the charging roller is driven to rotate while maintaining a relative speed difference with respect to the member to be charged. 5. A charging device according to claim 1, wherein a conductive fine powder is interposed in a contact nip portion between said charging roller and a member to be charged. apparatus. 6. A process cartridge including at least an image carrier and a charging device for charging said image carrier, said process cartridge being detachably mountable to an image forming apparatus main body, wherein said charging device is provided. A process cartridge characterized by being the charging device according to any one of the above. 7. An image forming apparatus to which a process cartridge can be attached and detached, wherein the process cartridge includes at least an image carrier and a charging device for charging the image carrier, and charges the image carrier. An image forming apparatus, wherein a charging device to be processed is the charging device according to any one of claims 1 to 5. 8. An image forming apparatus for forming an image by an image forming process including a step of charging the image carrier, wherein the charging device for charging the image carrier is any one of claims 1 to 5. An image forming apparatus, which is the charging device according to claim 1.