JP6904920B2 - Image forming device - Google Patents

Description

The present invention relates to a driving force transmission mechanism for transmitting a driving force from a device main body to a cartridge or the like in an image forming apparatus.

In a so-called process cartridge type electrophotographic image forming apparatus, a power transmission member connected to a drive source provided in the main body of the apparatus and a photosensitive drum in order to supply a rotational driving force to a rotating body such as a photosensitive drum provided in the process cartridge. Etc. are connected so that the driving force can be transmitted. Various configurations have been proposed as a driving force transmission mechanism for rotationally driving such a photosensitive drum or the like. In Patent Document 1, a twisted concave portion is provided in the coupling provided in the apparatus main body, a twisted convex portion is provided in the coupling provided in the photosensitive drum, and the photosensitive drum is driven by fitting these concave portion and the convex portion. The possible configurations are disclosed. Further, Patent Document 2 discloses a configuration in which a ground contact is provided which is connected when the coupling of the photosensitive drum and the coupling of the apparatus main body are fitted, and the ground is taken by the rotating portion of the end of the photosensitive drum. There is.

Japanese Patent No. 3480882 Japanese Patent No. 3839932

Here, in the coupling configuration in which the twisted uneven shape is fitted and drive-transmitted, it is necessary to provide a gap in the fitting portion of the uneven shape from the viewpoint of dimensional error generated at the time of manufacturing. This gap becomes a backlash component in the rotation direction when the photosensitive drum or the like is rotated, and the drive transmission performance of the driven portion of the photosensitive drum or the like may be deteriorated.

An object of the present invention is to provide a technique capable of stably transmitting a driving force.

In order to achieve the above object, the image forming apparatus of the present invention
An apparatus main body including a power source and a first coupling member that rotates by a driving force transmitted from the power source.
A cartridge that can be attached to and detached from the main body of the apparatus and includes a second coupling member that rotates by a driving force transmitted from the first coupling member and a rotating body that is connected to the second coupling member. Cartridge and
In the image forming apparatus having
The first coupling member is provided at a hole provided at the center of rotation of the first coupling member and recessed in the direction of the rotation axis of the first coupling member, and provided radially outside the hole from the center of rotation. A first drive transmission surface orthogonal to the rotation axis of the first coupling member is provided.
Said second coupling member includes a protrusion which fits into the protruding the hole in the direction of the axis of rotation of the second coupling member prior Symbol second coupling member provided on the rotation center of the projected from the center of rotation A second drive transmission surface that is provided on the outer side in the radial direction of the portion and is orthogonal to the rotation axis of the second coupling member that is in contact with the first drive transmission surface facing the first drive transmission surface is provided.
At least one of the first drive transmission surface and the second drive transmission surface is formed of a dielectric.
The apparatus main body causes a voltage generated by electrostatic adsorption force that is attracted to each other between the first drive transmission surface and the second drive transmission surface to be applied to the first coupling member and the second coupling member. It is characterized by including a voltage application unit to be applied between them.

According to the present invention, stable driving force can be transmitted.

Schematic cross-sectional view of the driving force transmission mechanism according to the first embodiment of the present invention. Schematic cross-sectional view of the image forming apparatus according to the embodiment of the present invention. Schematic cross-sectional view of the process cartridge according to the embodiment of the present invention. Schematic perspective view of the cleaning unit according to the first embodiment of the present invention. Schematic perspective view showing how the process cartridge is attached to and detached from the device body. Schematic cross-sectional view of the driving force transmission mechanism according to the first embodiment of the present invention. The figure explaining the relationship between the electrostatic adsorption force and the transferable torque Equivalent circuit diagram of coupling configuration using electrostatic adsorption force Diagram explaining the relationship between electrostatic adsorption force, current, and voltage The figure explaining the relationship between electrostatic adsorption force, current, and volume resistivity Schematic cross-sectional view of the driving force transmission mechanism according to the second embodiment of the present invention. Schematic cross-sectional view of the driving force transmission mechanism according to the second embodiment of the present invention. Schematic cross-sectional view of the driving force transmission mechanism according to the third embodiment of the present invention. Schematic cross-sectional view of the driving force transmission mechanism according to the third embodiment of the present invention. Schematic cross-sectional view of the driving force transmission mechanism according to the fourth embodiment of the present invention. Schematic perspective view of the cleaning unit according to the fourth embodiment of the present invention. Schematic perspective view of the coupling of the process cartridge according to the fourth embodiment of the present invention. Schematic perspective view showing how the process cartridge according to the fourth embodiment of the present invention is attached to and detached from the apparatus main body. Schematic perspective view of the coupling of the apparatus main body according to the fourth embodiment of the present invention. Schematic cross-sectional view of the driving force transmission mechanism according to the fourth embodiment of the present invention. Schematic cross-sectional view of the driving force transmission mechanism according to the fifth embodiment of the present invention. Schematic cross-sectional view of the driving force transmission mechanism according to the fifth embodiment of the present invention. Sectional drawing of coupling, photosensitive drum, and drive device which concerns on Example 6 of this invention Perspective view of the cleaner unit according to the sixth embodiment of the present invention. Perspective view of the apparatus main body and the process cartridge according to the sixth embodiment of the present invention. Configuration when the volume resistivity and thickness of the electrostatic adsorption function unit according to Example 7 of the present invention are constant, and each distribution diagram. Configuration in the case where the volume resistivity of the electrostatic adsorption function unit according to the seventh embodiment of the present invention has a distribution, and each distribution diagram. Configuration when the thickness of the electrostatic adsorption function portion according to Example 7 of the present invention is distributed, and each distribution diagram. The figure which showed the structure which gave the micropores to the electrostatic adsorption function part which concerns on Example 7 of this invention. Configuration when a medium resistance portion and a high resistance portion are provided in the electrostatic adsorption function portion according to the eighth embodiment of the present invention, and distribution diagrams thereof. The figure which showed the structure which provided the hole in the electrostatic adsorption function part which concerns on Example 8 of this invention. Configuration diagram in which a boss is provided in the electrostatic adsorption function portion according to the eighth embodiment of the present invention, and a fitting hole is provided in the drive side coupling. The figure which provided the boss of another member in the electrostatic adsorption function part which concerns on Example 8 of this invention, and the fitting hole in the drive side coupling. Configuration diagram in which the boss and the non-driving side coupling are further insulated from the electrostatic adsorption function portion according to the eighth embodiment of the present invention. Schematic cross-sectional view of the driving force transmission mechanism according to the first modification of the present invention. Schematic cross-sectional view of the driving force transmission mechanism according to the first modification of the present invention.

Hereinafter, the present invention will be described in detail based on the illustrated embodiments. However, the dimensions, materials, shapes, relative arrangements, and the like of the components described in this embodiment are not intended to limit the scope of the present invention to those.
(Example 1)
The image forming apparatus according to the embodiment of the present invention will be described with reference to FIGS. 1 to 6. Here, the image forming apparatus to which the present invention is applied is an image forming apparatus that forms an image on a recording material by using an electrophotographic image forming method, and specifically, a copying machine, a printer (LED printer, a laser). Printers, etc.), facsimile machines, word processors, etc. are applicable. Further, the image forming apparatus to which the present invention is applied is an image forming apparatus adopting a process cartridge method. That is, a device configuration in which a photosensitive drum (image carrier), which is an electrophotographic photosensitive member, and a process means acting on the photosensitive drum are integrated as a process cartridge, and the process cartridge is detachable (attachable) to the image forming apparatus main body. It is an image forming apparatus having. The process cartridge is composed of a plurality of units such as a cleaning unit equipped with a photosensitive drum, charging means, cleaning means, etc., and a developing unit provided with a developing roller (developer carrier), a developing container for accommodating the developing agent, and the like. May occur. Further, these units may be independently configured as a cartridge that can be attached to and detached from the device body. In the present invention, the cartridge includes not only a process cartridge but also a cartridge in which each of the above units is made into a cartridge.

In the following description, the direction of the rotation axis of the photosensitive drum is the longitudinal direction. Further, in the longitudinal direction, the side on which the photosensitive drum receives the driving force from the image forming apparatus main body is the driving side (the driven coupling 63 side in FIG. 1), and the opposite side is the non-driving side.

The overall configuration of the image forming apparatus and the image forming process of this embodiment will be described with reference to FIGS. 2 and 3. FIG. 2 is a schematic cross-sectional view of an image forming apparatus main body (hereinafter referred to as device main body A) and a process cartridge (hereinafter referred to as cartridge B) of the image forming apparatus according to the embodiment of the present invention. FIG. 3 is a schematic cross-sectional view illustrating the configuration of the cartridge B. Here, the apparatus main body A of the image forming apparatus is a component portion of the configuration of the image forming apparatus excluding the cartridge B.

<Overall configuration of electrophotographic image forming apparatus>
As shown in FIG. 2, the image forming apparatus according to the present embodiment is a laser beam printer using electrophotographic technology in which the cartridge B is detachably attached to and attached to the apparatus main body A. An exposure apparatus 3 (laser scanner unit) is arranged above the cartridge B mounted on the apparatus main body A. Further, a sheet tray 4 containing a recording material (hereinafter, referred to as a sheet material P) to be image-formed is arranged under the cartridge B. Further, the apparatus main body A includes a pickup roller 5a, a feeding roller pair 5b, a transport roller pair 5c, a transfer guide 6, a transfer roller 7, a transport guide 8, and a fixing device 9 along the transport direction D of the sheet material P. A discharge roller pair 10, a discharge tray 11, and the like are sequentially arranged. The fixing device 9 is composed of a heating roller 9a and a pressure roller 9b.

<Structure of the entire cartridge>
As shown in FIG. 3, the cartridge B is configured by combining the cleaning unit 60 and the developing unit 20. The cleaning unit 60 includes a cleaning frame 71, a photosensitive drum (hereinafter, drum) 62, a charging roller 66, a cleaning blade 77, and the like. On the other hand, the developing unit 20 includes a bottom member 22, a developing container 23, a developing blade 42, a developing roller 32, a magnet roller 34, a conveying member 43, a toner T, and the like. The cartridge B is formed by rotatably connecting the cleaning unit 60 and the developing unit 20 to each other.

<Cleaning unit configuration>
The configuration of the cleaning unit 60 will be described with reference to FIGS. 1 and 3 to 5. FIG. 1 is a schematic cross-sectional view of the driving force transmission mechanism according to the present embodiment, showing the configuration in the vicinity of the drum unit 61 including the configuration of the apparatus main body A. FIG. 4 is a schematic perspective view illustrating the configuration of the cleaning unit 60. FIG. 5 is a schematic perspective view showing a state in which the cartridge B is attached / detached to / from the apparatus main body A, and shows a state in which the opening / closing door 13 of the apparatus main body A is opened in order to attach / detach the cartridge B.

As shown in FIG. 3, the cleaning blade 77 is composed of a support member 77a made of sheet metal and an elastic member 77b made of an elastic material such as urethane rubber, and screws (not shown) at both ends of the support member 77a with respect to the cleaning frame 71. By fixing with), it is placed in a predetermined position. The elastic member 77b comes into contact with the drum 62 and removes residual toner from the outer peripheral surface of the drum 62. The removed toner is stored in the waste toner chamber 71b of the cleaning unit 60.

As shown in FIG. 4, the urging member 74 and the charged roller bearing 66c are attached to the cleaning frame 71. The shaft portion of the charging roller 66 is fitted into the charging roller bearing 66c. The charging roller 66 is urged against the drum 62 by an urging member 74 such as a spring, and is rotatably supported by the charging roller bearing 66c, and is driven to rotate as the drum 62 rotates. The charging roller 66 is fed using an electrode plate (not shown) as a feeding path.

The drum 62 is, for example, a drum 62 coated with an organic optical transmitter layer (OPC photoconductor) on the outer peripheral surface of a tubular body of an aluminum cylinder, and the aluminum cylinder functions as a conductive portion in the drum 62. As shown in FIG. 1, in the drum 62, a driven coupling 63 having a drum flange function portion 63f is coupled to one (driving side) tubular end portion in the longitudinal direction of the tubular body, and the other (non-driving side). ), A flange 64 (an end member having a flange-shaped portion) is connected to the tubular end portion. The drum flange functional portion 63f integrally formed with the driven coupling 63 and the flange 64 are in axial contact with the end face of the tubular body of the drum 62, respectively. In this way, the driven coupling 63 and the flange 64 are integrally coupled to the drum 62 to form an electrophotographic photosensitive drum unit (hereinafter, drum unit 61). A shaft hole is provided in the center of the flange 64, and the drum shaft 78 is inserted and fitted into the shaft hole.

As a method of connecting the drum 62 to the driven coupling 63 and the flange 64, caulking, adhesion, welding or the like can be used. The flange functional portion 63f and the flange 64 have conductivity, and the drum shaft 78, which is also the first electrode having conductivity, is electrically conductive with the ground electrode of the apparatus main body A. Further, the flange function portion 63f is provided with a coupling base material 63a that receives a driving force from the apparatus main body A. The drum unit 61 is rotatably supported by the cleaning frame 71.

As shown in FIG. 5, the cleaning unit 60 includes a positioning portion 80 having a peripheral surface concentric with the drum shaft 78 and a rotation stopper in order to accurately position the cleaning unit 60 on the device main body A when mounted on the device main body A. The portions 81 are provided at both ends of the longitudinal direction. With this configuration, the cartridge B including the developing unit 20 coupled to the cleaning unit 60 is accurately positioned on the apparatus main body A.

<Cartridge attachment / detachment>
As shown in FIG. 5, an opening / closing door 13 is rotatably attached to the apparatus main body A. When the opening / closing door 13 is opened, a link mechanism (not shown) operates in conjunction with the operation of the opening / closing door 13, so that the drive coupling 90 provided in the apparatus main body A moves in the longitudinal retract direction (drive coupling) of the cartridge B. Move in the direction of the rotation axis of 90). The apparatus main body A is provided with a guide rail 12, and the cartridge B is mounted in the apparatus main body A along the guide rail 12. At this time, the cartridge B is positioned on the apparatus main body A by engaging the positioning portion 80 and the rotation stopper 81 provided on the cleaning unit 60 described above with the positioning portion (not shown) of the apparatus main body A. When the opening / closing door 13 is closed, a link mechanism (not shown) operates in conjunction with the operation of the opening / closing door 13, and the drive coupling 90 approaches the driven coupling 63 provided on the cartridge B in the opposite direction to the above. It moves and the drive transmission surfaces of the coupling are joined together.

Then, as shown in FIG. 1, the drive coupling 90 driven by the motor 95 of the apparatus main body A is a driven coupling 63 provided in the cartridge B by the controller (control unit) 101 of the apparatus main body A as needed. (Fig. 6) and is attracted by the electrostatic force described later. As a result, the drum 62 coupled to the driven coupling 63 receives a driving force from the apparatus main body A and rotates.

<Image formation process>
The outline of the image formation process will be described with reference to FIGS. 2 and 3. Based on the print start signal, the drum 62 is rotationally driven in the direction of arrow R at a predetermined peripheral speed (process speed). The charging roller 66 to which the bias voltage is applied comes into contact with the outer peripheral surface of the drum 62 and uniformly charges the outer peripheral surface of the drum 62. The exposure apparatus 3 outputs the laser beam L according to the image information. The laser beam L passes through the exposure window portion 74 on the upper surface of the cartridge B, and scans and exposes the outer peripheral surface of the drum 62. As a result, an electrostatic latent image corresponding to the image information is formed on the outer peripheral surface of the drum 62.

As shown in FIG. 3, in the developing unit 20 as a developing device, the toner T in the toner chamber 29 is agitated and conveyed by the rotation of the conveying member 43, and is sent out to the toner supply chamber 28. The toner T is supported on the surface of the developing roller 32 by the magnetic force of the magnet roller 34 (fixed magnet). The toner T is frictionally charged by the developing blade 42, and the layer thickness of the peripheral surface of the developing roller 32 is regulated. The toner T is transferred to the drum 62 according to the electrostatic latent image, and is visualized as a toner image (developer image).

As shown in FIG. 2, the sheet material P stored in the lower part of the apparatus main body A is moved from the sheet tray 4 by the pickup roller 5a, the feeding roller pair 5b, and the transport roller pair 5c together with the output timing of the laser beam L. Will be sent. Then, the sheet material P is supplied to the transfer position between the drum 62 and the transfer roller 7 via the transfer guide 6. At this transfer position, the toner image is sequentially transferred from the drum 62 to the sheet material P. The sheet material P to which the toner image is transferred is separated from the drum 62 and conveyed to the fixing device 9 along the conveying guide 8. Then, the sheet material P passes through the nip portion of the heating roller 9a and the pressure roller 9b constituting the fixing device 9. Pressurization / heat fixing treatment is performed at this nip portion, and the toner image is fixed to the sheet material P. The sheet material P that has undergone the toner image fixing process is conveyed to the discharge roller pair 10 and discharged to the discharge tray 11.

As shown in FIG. 3, the drum 62 after transfer is used again in the image forming process after the residual toner on the outer peripheral surface is removed by the cleaning blade 77. The toner removed from the drum 62 is stored in the waste toner chamber 71b of the cleaning unit 60. In the above, the charging roller 66, the developing roller 32, and the cleaning blade 77 are process means for acting on the drum 62.

<Drive transmission coupling (driving force transmission mechanism)>
The configuration of the drive transmission coupling, which is the basis of the present invention, will be described in detail with reference to FIGS. 1 and 6. FIG. 6 is a schematic cross-sectional view of the drive transmission coupling (driving force transmission mechanism) according to the present embodiment, showing a state before the drive coupling 90 and the driven coupling 63 are connected. Is. The drive transmission coupling of the present invention is composed of a drive coupling 90 provided in the apparatus main body A and a driven coupling 63 provided in the cartridge B. First, the configuration of the driven coupling 63, which is the driven coupling provided in the cartridge B, will be described.

As shown in FIGS. 1 and 6, a driven coupling 63 as a coupling means is provided at one end in the longitudinal direction of the drum 62 attached to the cartridge B. The driven coupling 63 has a coupling base material 63a. The drum coupling base material 63a is integrally provided with a drive transmission function portion 63b having a diameter of 16 mm and a drum flange function portion 63f. On the tip surface of the drive transmission function unit 63b, a drive transmission surface 63c, which is a second electrode as the drive transmission function unit that comes into contact with the drive coupling 90 provided in the apparatus main body A in a surface configuration, is provided on the drum 62 and the cover. It is provided as a surface extending in a direction orthogonal to the rotation axis of the drive coupling 63.

Here, the surface roughness (center line average roughness) Ra of the drive transmission surface 63c was set to 0.2 μm. The surface roughness Ra can be appropriately selected as long as it is 0.2 μm or less. When the surface roughness Ra exceeds 0.2, the electrostatic adsorption force decreases. The surface roughness Ra of the coupling member or the dielectric is defined by, for example, the center line average roughness measured using a surface roughness measuring instrument based on the JIS surface roughness "JIS B 0601 (2001)". can do.

On the drum 62 rotation axis of the drive transmission surface 63c, a circular boss 63d having a diameter of 4 mm that defines the center of rotation is provided by fitting one end with the drive coupling 90. The circular boss 63d is a separate member from the driven coupling 63, and the other end thereof is fitted into the hole 63h of the driven coupling 63. The hole 63h is provided on the rotation axis of the drum 62 of the drive transmission surface 63c with a diameter of 4 mm, and a C chamfer 63e of 2 mm is provided around the entrance (opening) thereof. The engaging portion (fitting portion) between the hole 63h and the circular boss 63d is firmly fixed with an epoxy adhesive. Here, the method of fixing the circular boss 63d to the coupling base material 63a is not limited to an adhesive such as epoxy, and can be appropriately selected such as screwing type or press fitting by knurling.

The driven coupling 63 has an outer peripheral surface formed in the direction opposite to the drive transmission function portion 63b in the axial direction of the drum 62 of the drum flange function portion 63f so as to match the inner peripheral surface of the tubular end portion of the drum 62. It includes a fitting portion 63f1. When fixing the driven coupling 63 to the drum 62, the fitting portion 63f1 is fitted to the inner surface of the drum 62, and the drum flange functional portion 63f is positioned on the drum 62 (contacting the end surface of the tubular end portion). ), The fitting portion 63f1 and the drum 62 are crimped. The method of fixing the drum flange functional portion 63f is not limited to caulking, and can be appropriately selected such as adhesion.

The material of each component will be described. As the material of the coupling base material 63a, conductive aluminum was used. However, the material of the coupling base material 63a is not limited to aluminum. For example, metals such as iron and copper, conductive ceramics, and conductive resins commonly used in process cartridges, specifically, polyacetal, polyester, epoxy resin, etc. with a conductive agent added are used. It does not matter if it is a molded product. As the conductive agent, an electron conductive agent, an ionic conductive agent, or the like can be appropriately selected. As a guide, the volume resistivity of the driven coupling 63 ^{may be 1 × 10 10} Ωcm or less. By selecting the above configuration and material, the driven coupling 63 is electrically conductive with the drum 62.
Further, the flange 64 described in the configuration description of the cleaning unit 60 is conductive, and the drum shaft 78, which is also conductive, is electrically conductive with the ground of the apparatus main body A. With the above configuration, when the process cartridge is mounted on the device main body A, the driven coupling 63 is electrically connected to the ground of the device main body A via the drum shaft 78, and is on the ground side with respect to the drive coupling 90. Will be located in.

The material of the circular boss 63d uses polyacetal, which is an insulating member, in order to electrically insulate the drive coupling 90, and is electrically insulated from the conductive coupling base material 63a. is doing. Here, as for the material of the circular boss 63d, a material that can electrically maintain an insulating relationship with the coupling base material 63a may be appropriately selected, and ceramic, polyester, epoxy resin, or the like can be appropriately selected. As a guideline for insulation, the volume resistivity is 1 × 10 ¹⁵ Ωcm or more.

Next, the configuration of the drive coupling 90, which is the coupling on the drive side provided in the apparatus main body A, will be described. As shown in FIG. 1, the drive coupling 90 is roughly composed of a coupling base material 90a and an electrostatic adsorption function portion 90g.

The coupling base material 90a has a drive transmission function portion 90b formed in a cylindrical shape having a diameter of 16 mm. The electrostatic adsorption function unit 90g is adhesively fixed to the tip of the drive transmission function unit 90b. The drive transmission function unit 90b has a relative surface 90f that faces the drive transmission surface 63c of the driven coupling 63 in a surface configuration when the cartridge B is mounted on the apparatus main body A. The relative surface 90f and the drive transmission surface 63c are surfaces extending in a direction orthogonal to the rotation axis of the drive coupling 90. The drive transmission surface 90c is also a surface orthogonal to the rotation axis (rotation axis) of the drive coupling 90. Further, a Φ4 fitting hole 90d into which the circular boss 63d of the driven coupling 63 is inserted and fitted is provided in the rotation center of the relative surface 90f of the coupling base material 90a. The circular boss 63d fitted in the fitting hole 90d comes into contact with the drive transmission function portion 90b and also with the electrostatic suction function portion 90g. Further, a 2 mm C chamfer 90e is provided around the entrance of the fitting hole 90d.

The electrostatic adsorption function portion 90 g, which is the third electrode, is composed of a circular sheet member having a surface roughness Ra of 0.2 μm, a thickness of 120 μm, and a through hole of Φ4 in the central portion, and having an outer diameter of Φ20 mm. Here, the thickness of the electrostatic adsorption function portion 90 g is not particularly limited, and may be appropriately selected according to the electrostatic adsorption force and the required power, which will be described later. Further, the surface roughness Ra can be appropriately selected as long as it is 0.2 μm or less. Here, the reason for setting the surface roughness Ra to 0.2 or less is that when the surface roughness Ra exceeds 0.2, the electrostatic adsorption force decreases. The electrostatic adsorption function portion 90g uses a conductive double-sided tape having a diameter of 8 mm, which is the same as the diameter of the C chamfer 90e provided around the fitting hole 90d, and is used as a relative surface 90f of the coupling base material 90a. Is fixed to. At the time of fixing, the through hole of Φ4 of the electrostatic suction function portion 90 g and the fitting hole 90d of Φ4 are aligned so that the circular boss 63d can be inserted into the through hole of the electrostatic suction function portion 90 g. Here, the holes provided in the conductive double-sided tape may have a size equal to or larger than the diameter of the C chamfer 90e provided around the fitting hole 90d, and can be appropriately selected according to the required adhesive strength. As a result, the electrostatic adsorption function unit 90g is in contact with the drive transmission surface (second drive transmission surface) 63c of the drive transmission function unit 63b of the driven coupling 63, and the drive transmission surface (first) of the drive transmission function unit 90b is in contact with the drive transmission function unit 90b. Drive transmission surface) Functions as 90c.

The material of each component will be described. As the material of the coupling base material 90a, conductive aluminum was used. The material of the coupling base material 90a is not limited to aluminum. For example, metals such as iron and copper, conductive ceramics, and conductive resins commonly used in process cartridges, specifically, polyacetal, polyester, epoxy resin, etc. with a conductive agent added are used. It does not matter if it is a molded product. As the conductive agent, an electron conductive agent, an ionic conductive agent, or the like can be appropriately selected. As a guide, the volume resistivity of the drive coupling 90 ^{should be 1 × 10 10} Ωcm or less.

As the material of the electrostatic adsorption function portion 90 g, a modified polyimide having a ^{volume resistivity of 1 × 10 12 Ωcm, which functions as a dielectric, was used.} Here, the electrostatic adsorption function unit 90 g ^{may be appropriately selected in the range of 1 × 10 10} Ωcm to 1 × 10 ¹⁴ Ωcm in volume resistivity according to the required electrostatic adsorption force described later. The material is not particularly limited, such as polyacetal, polyvinylfluoride den, and urethane rubber, and the conductive agent for adjusting the volume resistivity can be appropriately selected from an electronic conductive agent, an ionic conductive agent, and the like. be. Examples of the electronic conductive agent include carbon black and graphite exhibiting electron conductivity; oxides such as tin oxide; metals such as copper and silver; conductive particles obtained by coating the particle surface with an oxide or metal to impart conductivity. Can be mentioned. Examples of the ionic conductive agent include quaternary ammonium salts exhibiting ionic conductivity and ionic conductive agents having ion exchange properties such as sulfonates.

The dielectric defined in the present invention is a substance that does not easily pass an electric current and generates dielectric polarization when an electric field is applied, and has a resistance component and a dielectric component in a conducting mechanism such as an insulator containing conductive particles. This also includes substances with. Here, the volume resistivity of the electrostatic adsorption function portion 90 g (sheet member) was measured using a Mitsubishi Chemical Analytical High Restor UP MCP-HT450 type and a ring probe: UR at an applied voltage of 1000 v.

Next, the conductive double-sided tape used for fixing the coupling base material 90a and the electrostatic adsorption function portion 90 g was a conductive double-sided tape No. 1 manufactured by Hitachi Maxell Co., Ltd. 5805 was used. Here, the method of bonding the coupling base material 90a and the dielectric is not limited to the conductive double-sided tape, and can be appropriately selected from a configuration using a conductive adhesive and the like.

On the other hand, the drive coupling 90 is coupled to a large gear 97 that transmits the driving force of the motor 95 as a drive source to the drum 62 with the same rotation axis. The large gear 97 is a gear, and the gear is meshed with a small gear 96 of the tooth, which is fixed to or integrally provided with the shaft of the motor 95. Here, the twisting direction of the spiral tooth gear of the large gear 97 is set in the direction in which the large gear 97 exerts a thrust force on the cartridge B side when the small gear 96 drives the large gear 97.

As the material of the large gear 97, the sliding grade polyacetal used in the electrophotographic image forming apparatus was used. Here, the material of the large gear 97 needs to be electrically insulated from the drive transmission coupling. From this, the material of the large gear 97 is not limited to the sliding grade polyacetal, and can be appropriately selected as long as it is a material of ^{1 × 10 15 Ωcm or more as a guideline for the volume resistivity.} As the material of the small gear 96, the sliding grade polyacetal used in the electrophotographic image forming apparatus was used. This material can be appropriately selected based on performance such as required life without limitation of volume resistivity.

Alternatively, the material of the large gear 97 may be selected from a material having the same conductivity as that of the drive coupling 90, and the large gear 97 and the drive coupling 90 may be integrally molded. ^{In this case, select a material of 1 × 10 15} Ωcm or more for the small gear 96 as a guideline for the volume resistivity, and insulate the upstream side of the drive from the small gear 96. That is, any component interposed between the drive coupling 90 and the drive motor 95 may be insulated by selecting a material having a ^{volume resistivity of 1 × 10 15 Ωcm or more.}

The coupling configuration of the drive coupling 90 and the large gear 97 will be described. The connection between the drive coupling 90 and the large gear 97 has a press-fitting configuration in which a knurl is cut at the fitting portion of the drive coupling 90. Here, the coupling configuration is not limited to the press-fitting configuration described above, and a configuration by adhesion, insert molding, or the like can be appropriately selected while satisfying the required drive transmission torque. Then, the drive coupling 90 comes into contact with the power feeding contact 98 provided in the apparatus main body A at the end of the drive transmission coupling on the side opposite to the cartridge B in the rotation axis direction. The power supply contact 98 is electrically connected to the high voltage power supply 100 provided in the apparatus main body A. With this configuration, the high-voltage power supply 100 and the drive coupling 90 are electrically conductive. Then, the controller (control unit) 101 provided in the apparatus main body A controls the power supply on / off from the high-voltage power supply 100 to the drive coupling 90.

The coupling action of the drive transmission coupling accompanying the mounting of the cartridge B on the apparatus main body A will be described. According to the above-described configuration, when the opening / closing door 13 of the device main body A is opened, the drive coupling 90 provided in the device main body A moves in the direction away from the cartridge B in the direction of its rotation axis. Next, the cartridge B is attached to the apparatus main body A. Then, by closing the opening / closing door 13, the drive coupling 90 that had previously moved to the retracted position moves to the cartridge B side. By this movement, the circular boss 63d provided in the driven coupling 63 and the fitting hole 90d provided in the drive coupling 90 are engaged with each other, and the rotation center of the drive coupling 90 is determined. Further, the drive transmission surfaces 90c and 63c of the drive coupling 90 and the driven coupling 63 as drive transmission function units come into contact with each other.

<Drive transmission mechanism>
The drive transmission mechanism on the drive transmission surfaces 90c and 63c described above for driving the photosensitive drum by the drive transmission coupling will be described with reference to FIGS. 1 and 6. In the present invention, the electrostatic adsorption action by the Johnson-Labeck force is used as a means for obtaining friction on the drive transmission surfaces 90c and 63c. The Johnson-Labeck force is the outermost surface of the dielectric layer (drive transmission surface), which is the adsorption interface, by reducing the volume resistivity of the dielectric (electrostatic adsorption function unit 90 g), which facilitates the transfer of electric charges in the dielectric. It is a force generated by inducing a large amount of electric charge in 90c). Generally, a large force is generated as compared with the force (= called Coulomb force) generated when an insulator having a very large resistance component is used as the dielectric (electrostatic adsorption function portion 90 g). That is, the electric charge applied to the electrode (feeding contact 98) moves to the outermost surface of the dielectric layer (drive transmission surface 90c) through the dielectric layer (electrostatic adsorption function portion 90g). Then, while a part of the electric charge transferred to the outermost surface of the dielectric layer (drive transmission surface 90c) flows to the object to be adsorbed (drive transmission surface 63c), the object to be adsorbed (drive transmission surface 63c) with respect to this charge. It is charged by electrostatic induction or dielectric polarization to generate electrostatic adsorption force.

Here, from the above description, it can be seen that the electrostatic adsorption force is proportional to the width of the region where the current flows between the electrodes and the applied voltage. Therefore, the first electrode (drum shaft 78), which is the ground path, has a function as a ground if a region for energizing even one point is secured. On the other hand, it can be seen that the second electrode (drive transmission surface 63c) and the third electrode (electrostatic adsorption function unit 90 g) are different in that the adsorption force is exerted depending on the area of energization. From this, the second electrode (drive transmission surface 63c) and the third electrode (electrostatic adsorption function unit 90 g) need a contact area corresponding to the required electrostatic adsorption force, and contact more effectively. One of the means for securing the area is the surface roughness of the electrode. For this reason, in the present invention, the surface roughness Ra of the electrode surface that generates electrostatic adsorption force is set to 0.2 or less. As a result, the contact area for energizing the second and third electrodes can be made smaller than when the surface roughness Ra is larger than 0.2.

The drive transmission action of the drive transmission coupling accompanying the printing operation will be described. As described above in the section of attaching / detaching the CRG, the drive transmission surfaces 90c and 63c of the drive transmission coupling are in a joined state as the cartridge B is attached to the device main body A. Then, along with the print signal, the controller 101 provided in the apparatus main body A applies a voltage of -1 kv from the high-voltage power supply 100 to the drive transmission coupling via the power supply contact 98. As a result, the coupling base material 90a ⇒ electrostatic adsorption function part 90g as a dielectric layer ⇒ drive transmission surface 90c ⇒ drive transmission surface 63c ⇒ coupling base material 63a ⇒ conductive part on the inner surface of the photosensitive drum 62 ⇒ flange 64 ⇒ drum shaft 78 ⇒ Current flows to the ground through the ground contact 99.

This current flow causes the following phenomenon when compared with the above-mentioned Johnsen-Labeck force generation mechanism. That is, the electric charge applied to the coupling base material 90a as the electrode (one electrode) passes through the electrostatic adsorption function portion 90g as the dielectric layer (dielectric) and has the electrostatic adsorption function as the outermost surface of the dielectric layer. It moves to the drive transmission surface 90c which is the surface of the part 90g. With respect to this charge, the drive transmission surface 63c of the driven coupling 63 as the object to be adsorbed (the other electrode) is charged by electrostatic induction or dielectric polarization. As a result, an electrostatic attraction force is generated between the drive transmission surface 90c and the drive transmission surface 63c. Then, the motor 95 provided in the apparatus main body A is driven, and the large gear 97 is driven via the small gear 96. Along with this operation, the electrostatic attraction force is converted into the frictional force between the drive transmission surface 90c and the drive transmission surface 63c, so that the drum 62 is driven.

More specifically, the configuration of this embodiment can be described as follows as a configuration in which an electrostatic adsorption force is generated between a pair of opposing electrodes facing each other with a dielectric interposed therebetween. That is, in the drive coupling 90 as the first coupling member, the joint portion (relative surface 90f and its vicinity region) with the electrostatic adsorption function portion 90g as a dielectric material is attached to one of the counter electrodes. handle. Further, in the driven coupling 63 as the second coupling member, the joint portion (drive transmission surface 63c and its vicinity region) with the electrostatic adsorption function portion 90 g corresponds to the other electrode of the counter electrodes. .. When a voltage is applied between the drive coupling 90, the electrostatic adsorption function unit 90 g, and the driven coupling 63 by the high-voltage power supply 100, a negative charge is induced on the drive transmission surface 90c of the electrostatic adsorption function unit 90 g. NS. Along with this, a positive charge is induced in the drive transmission unit 63c of the opposite non-drive coupling 63. By forming such a charge arrangement, electrostatic adsorption force is generated between the drive coupling 90 and the electrostatic adsorption function unit 90 g, and between the electrostatic adsorption function unit 90 g and the driven coupling 63, respectively. Then, they are in a state of being adsorbed to each other. This electrostatic attraction force is strong enough to transmit the rotational driving force transmitted from the motor 95 as a power source to the drive coupling 90 to the driven coupling 63 via the electrostatic attraction function unit 90g without loss. The voltage applied by the high-voltage power source 100 is adjusted so as to be. In the present embodiment, the configuration related to the implementation of the voltage application for generating the electrostatic attraction such as the high voltage power supply 100, the controller (control unit) 101, the power supply contact 98, and the ground contact 99 is applied to the voltage application unit in the present invention. handle.

Actually, by applying a voltage of -1 kv, a current of about 170 μA flowed and a drive transmission torque of about 1 kgfcm was obtained.

Here, in the coupling base material 90a on the driving side and the coupling base material 63a on the driven side, C chamfers 90e and 63e of 2 mm are provided around the fitting portion of the circular boss 63d, and the inner diameter is substantially the same as that of the circular boss 63d. 90 g of the electrostatic adsorption function part having the through hole of the above was constructed. Further, the outer diameter of the electrostatic adsorption function portion 90g is made 4 mm larger than the outer diameter of the drive transmission function portions 90b and 63b of the coupling base materials 90a and 63a. As a result, the creepage distance between the coupling base material 90a and the coupling base material 63a via the electrostatic adsorption function portion 90g is substantially 4 mm. The creepage distance between the coupling base material 90a and the coupling base material 63a via the electrostatic adsorption surface is sufficient to suppress the occurrence of a leak (current flow that does not contribute to electrostatic adsorption) between the members. Distance is set. The creepage distance for preventing this leak is appropriately set according to the device configuration and the like.

Further, it is known that when a voltage exceeding the withstand voltage of the electrostatic adsorption function unit is applied, dielectric breakdown occurs and electrostatic adsorption force cannot be obtained. Therefore, the voltage for obtaining the electrostatic adsorption force is set to be equal to or less than the dielectric strength of the electrostatic adsorption function unit 90 g.

<Transmissible torque and electrostatic adsorption force>
Here, based on the coupling configuration shown in FIG. 7A, the relationship between the transmissible torque and the electrostatic attraction force in the driving force transmission mechanism utilizing the electrostatic attraction force will be described. The coupling configuration shown in FIG. 7A is a simplified configuration in the coupling configuration of this embodiment by eliminating the centering mechanism by the circular boss. Specifically, the tip surface of the drive transmission function unit 90b of the drive coupling rig 90 and the tip surface of the drive transmission function unit 63b of the driven coupling 63 facing the tip surface thereof are a circular end surface from which fitting holes are eliminated. It has become. Further, the electrostatic adsorption function unit 63g has no through hole for inserting the circular boss of the present embodiment, is adhesively fixed to the driven coupling 63, and is the same as the drive transmission function units 90b and 63b. It is formed in the diameter. That is, the tip surface of the drive transmission function unit 90b of the drive coupling 63 is a drive transmission surface, and the drive force is transmitted by electrostatically attracting the drive transmission surface and the electrostatic adsorption function unit 63g to each other. It is composed.

FIG. 7B is a graph showing the relationship between the electrostatic attraction force and the transferable torque. The electrostatic adsorption force and the transferable torque are expressed by the following equations.
In the formula (1), T: transferable torque [Nm], μ: friction coefficient between the electrostatic attraction function unit 63g and the drive coupling 90, D: outer diameter [m] of the electrostatic attraction function unit 63g, p. (R): Electrostatic attraction force [Pa], r: Radial position [m] from the center of rotation.
When the electrostatic adsorption force is constant in the drive transmission surface, the equation (1) is expressed as follows.
When the formula (2) is shown graphically, it becomes as shown in FIG. 7 (b). FIG. 7B is a calculation result when the outer diameter D is 16 mm and the friction coefficient μ is 0.3. Looking at this figure, it can be seen that the transferable torque increases in proportion to the electrostatic adsorption force. For example, when it is desired to set the transferable torque to 0.1 Nm, it is sufficient to obtain about 300 kPa as the electrostatic adsorption force.

The electrostatic adsorption force will be described with reference to FIGS. 8 and 9.
FIG. 8 shows an equivalent circuit showing the micro-contact state of the drive transmission function unit 90b of the drive coupling 90 and the electrostatic adsorption function unit 63 g and their electrical properties in the coupling configuration shown in FIG. 7 (a). It is a figure. In this figure, the electrostatic adsorption force after a sufficient time has passed after the voltage is applied is expressed by the following equation.
In the formula (3), ε0: the dielectric constant in the atmosphere, Rg: the contact resistance [Ω] between the electrostatic adsorption function unit 63 g and the drive transmission function unit 90b, and Rb: the volume resistance [Ω] of the electrostatic adsorption function unit 63 g. be. Further, V: applied voltage, d: average void distance [m] between the drive transmission function unit 90b and the electrostatic adsorption function unit 63 g. Equation (3) shows that the electrostatic adsorption force changes depending on the volume resistance Rb of the electrostatic adsorption function unit 63e, and in order to increase the electrostatic adsorption force, the volume resistance of the electrostatic adsorption function unit 63 g It turns out that it should be made smaller.

<Volume resistivity and electrostatic adsorption force>
FIG. 9 shows the results of measuring the electrostatic adsorption force and the current flowing at that time. To measure the electrostatic adsorption force, the cartridge B provided with the electrostatic adsorption function unit 63 g is taken out from the device main body A, and the electrostatic adsorption function unit 63 g is brought into close contact with an aluminum plate resembling a drive coupling 90 to perform electrostatic adsorption. This was done by measuring the force of peeling 63 g of the functional part from the aluminum plate. In this preliminary test, the volume resistivity of 63 g of the electrostatic adsorption function unit was 1 × 10 ¹¹ Ωcm and 1 × 10 ¹³ Ωcm, and the thickness was 75 μm. The volume resistivity here is obtained from the current value when the applied voltage is 100 V, and in the case of medium resistance materials, the volume resistivity is generally determined by the applied voltage depending on the temperature characteristics of the material and the non-ohmic conduction mechanism. Changes.

Looking at the measurement results of the electrostatic adsorption force in FIG. 9A, it can be seen that the smaller the volume resistivity, the larger the electrostatic adsorption force. This is as described in equation (3). The electrostatic attraction force obtained in the so-called medium resistance region having a volume resistivity of about 1 × 10 ^{9 Ωcm to 1 × 10 14 Ωcm is called a Johnsen-Labeck force.} While a large force can be obtained from the Johnson-Labeck force, it is necessary to pay attention to the power consumption because a leak current is generated. Actually, looking at the current measurement result of FIG. 9B, when the volume resistivity is 1 × 10 ¹¹ Ωcm, when the applied voltage is 400 V, a current of about 400 μA is generated, and the power consumption is 400 V × 400 μA = 0.16 W. It becomes.

On the other hand, it was found from the test results that if the volume resistivity is made too small, the electrostatic adsorption force is conversely reduced. FIG. 10 shows the result of measuring the electrostatic adsorption force and the current flowing at that time in relation to the volume resistivity, and the same test as the above-mentioned preliminary test described with reference to FIG. 9 is applied. This is the result of setting the voltage to 200V. Explaining with reference to FIG. 8, when the volume resistivity is large, the current does not flow, so that the amount of charge accumulated in the gap becomes small. Therefore, the electrostatic adsorption force depending on the electric charge becomes small. That is, the Johnsen-Labeck force does not work. On the other hand, when the volume resistivity is small, the amount of conductive carbon precipitated on the surface increases, and the contact resistance Rg decreases. As can be seen from the equation (3), when Rg becomes smaller than the volume resistance Rb, the voltage Vg applied to the gap becomes smaller. Then, the electrostatic adsorption force decreases. That is, it is not always the case that the electrostatic adsorption force is increased if the volume resistivity of the electrostatic adsorption function unit 63 g is reduced, and there is a large volume resistivity at which the electrostatic adsorption force is the largest. I understand.

<Advantages of this example>
In this embodiment, a centering configuration (centering function unit that defines the center of rotation) for aligning the rotation center axes of the drive coupling 90 and the driven coupling 63 using a circular boss 63d is provided in the vicinity of the rotation center axis. It is located in the region, that is, in the central part of the circular suction joint surface. The lossless transmission of rotational driving force on a circular joint surface perpendicular to the rotation axis means that the joint surfaces do not shift from each other in the circumferential direction, that is, the drive coupling 90 and the driven coupling 63 in the rotation direction. Relative movement to and from is regulated. What is important in suppressing the displacement of the joint surface in the circumferential direction is the suction force in the region on the outer peripheral side away from the center of the rotation axis where the joint area becomes relatively wide. As shown in the equation (1), the transferable torque T is determined by the integral of the product of the radial position r and the electrostatic attraction force P (r) at that position. That is, the electrostatic adsorption force on the outer side (larger r) in the radial direction contributes more to the transmissible torque than on the inner side (small r) in the radial direction of the electrostatic adsorption function portion. Therefore, if a sufficient suction force can be secured in the region on the outer peripheral side, it is possible to transmit the rotation driving force without loss in the region near the center of the rotation axis without exerting the suction force. In this embodiment, the electrostatic adsorption joint surface of the drive coupling 90, the driven coupling 63, and the electrostatic adsorption function portion 90 g is an annular surface having an inner diameter and an outer diameter, and the rotation center portion inside the joint surface. The alignment configuration is arranged in. Further, the circular boss 63d, which is a centering member, is composed of an insulating member, and the opening of the fitting hole of each coupling is chamfered. Further, the inner diameter and the outer diameter of the electrostatic adsorption function portion 90g are expanded to the inner diameter side and the outer diameter side with respect to the joining region (joining surface) with each coupling, respectively. That is, the outer diameter of the surface facing each coupling in the electrostatic adsorption function portion 90g is larger than the outer diameter of the bonding region (joining surface) with each coupling, and the inner diameter of the surface facing each coupling is large. , The configuration is smaller than the inner diameter of the joint region (joint surface) with each coupling. Further, the electrostatic adsorption function portion 90g has an inner diameter of the through hole substantially the same as the outer diameter of the circular boss 63 so as to come into contact with the circular boss 63 on the inner diameter side of the annular joint surface. As a result, it is possible to reliably align the drive coupling 90 and the driven coupling 63 and to generate a stable electrostatic adsorption force without leakage, and it is possible to realize a lossless drive force transmission.

(Modification example 1)
Next, a modification 1 which is a modification of this embodiment will be described. In this modification, for the purpose of reducing the power consumption of the drive transmission coupling using electrostatic adsorption described in the above embodiment, magnetic adsorption (magnetic adsorption force) is used instead of electrostatic adsorption. be.

FIG. 35 is a schematic cross-sectional view of the driving force transmission mechanism according to the first modification, showing a state in which the driving coupling 900 and the driven coupling 630 are connected. FIG. 36 is a schematic cross-sectional view of the driving force transmission mechanism according to the first modification, showing a state in which the drive coupling 900 and the driven coupling 630 are disconnected from each other. Since other configurations are the same as those in the first embodiment, the description thereof will be omitted.

As shown in FIGS. 35 and 36, instead of the electrostatic adsorption function portion, a magnet portion 630 g on the driven side coupling 630 side and a magnetic material portion 900 g on the drive coupling 900 side, which are magnetic adsorption function portions, are provided. It was configured.
The magnet portion 630g has a through hole of Φ4, and the through hole and the fitting hole 630h of Φ4 are aligned with the relative surface 630f2 of the coupling base material 630a and fixed with double-sided tape or the like. Similarly, the magnetic material portion 900 g also has a through hole of Φ4, and the through hole and the fitting hole 900d of Φ4 are aligned with the relative surface 900f of the coupling base material 900a and fixed with double-sided tape or the like. Will be done.

As shown in FIG. 35, by bringing the magnet portion 630 g and the magnetic body portion 900 g close to each other, the circular boss 630d is inserted into the fitting hole 900d, and the core that aligns the rotation center axes of the drive coupling 900 and the driven coupling 630. After the alignment is performed, the drive transmission surface 630c of the magnet portion 630 g and the drive transmission surface 900c of the magnetic body portion 900 g are magnetically attracted to each other. As a result, the drive coupling 900 and the driven coupling 630 are connected together with reliable alignment. The drive transmission surface 630c is a surface orthogonal to the rotation axis of the driven coupling 630, and the drive transmission surface 900c is a surface orthogonal to the rotation axis of the drive coupling 900.

Next, a method of disconnecting the drive coupling 900 and the driven coupling 630 will be described. As shown in FIG. 36, in order to separate the drive transmission surface 630c of the magnet portion 630g and the drive transmission surface 900c of the magnetic body portion 900g, a separation member 110 provided in the apparatus main body A is inserted between the drive transmission surfaces 630c and 900c. do. As a result, the magnet portion 630 g and the magnetic body portion 900 g are separated from each other. At this time, the drive coupling 900 moves to the left side of FIG. 36 in the direction of its rotation axis, and forms a space for the separating member 110 to enter between the drive coupling 900 and the driven coupling 630. A link mechanism (not shown) connects the opening / closing door 13 and the separating member 110 so that the separating member 110 is inserted in conjunction with the operation of opening the opening / closing door 13. By this link mechanism, the operation of pulling out the separating member 110 from between the drive transmission surfaces 630c and 900c is performed in conjunction with the operation of closing the opening / closing door 13.

With the above configuration, it is possible to achieve the transmission of the driving force without the backlash of the driving transmission coupling.
In this modification, a ferrite magnet was used for the magnet portion 630 g, and iron was used for the magnetic material portion 900 g. However, the material of the magnet portion 630 g is not limited to the ferrite magnet, and a permanent magnet such as a neodymium magnet can be appropriately selected. Further, the material of the magnetic material portion 900 g is not limited to iron, and magnetic materials such as ferrite, cobalt, nickel, and gadolinium can be appropriately selected.

Needless to say, in order to obtain a desired drive transmission force, it is possible to appropriately select the area of the magnetic body portion 900 g and the magnetic force of the magnet portion 630 g.
Further, a magnetic material portion may be arranged on the driven side coupling 630 side and a magnet portion may be arranged on the drive coupling 900 side.

(Example 2)
The second embodiment will be described with reference to FIGS. 11 and 12. The first embodiment has a configuration in which 90 g of the electrostatic adsorption function portion as a dielectric layer is arranged in the drive coupling 90, but the configuration is not limited to this.

FIG. 11 is a schematic cross-sectional view of the driving force transmission mechanism according to the second embodiment, showing a state before the driving coupling 90 and the driven coupling 63 are connected. FIG. 12 is a schematic cross-sectional view of the driving force transmission mechanism according to the second embodiment, showing a state in which the driving coupling 90 and the driven coupling 63 are connected.

As shown in FIGS. 11 and 12, the electrostatic adsorption function portion as the dielectric layer is the electrostatic adsorption function portion 63 g (second dielectric) on the driven side coupling 63 side and the electrostatic attraction on the drive coupling 90 side. It may be configured so as to be divided and arranged in the adsorption function portion 90 g (first dielectric). The electrostatic adsorption function portion 63g has a through hole of Φ4, and the through hole and the fitting hole 63h of Φ4 are aligned with the relative surface 63f2 of the coupling base material 63a to form the above-mentioned conductive double-sided tape or the like. Is fixed by. Similarly, the electrostatic adsorption function portion 90g also has a through hole of Φ4, and the through hole and the fitting hole 90d of Φ4 are aligned with the relative surface 90f of the coupling base material 90a to form the above-mentioned conductivity. It is fixed with double-sided tape or the like. When a voltage is applied, dielectric polarization occurs in each of the electrostatic adsorption function units 63g and 90g, and the drive transmission surface 63c of the electrostatic adsorption function unit 63g and the drive transmission surface 90c of the electrostatic adsorption function unit 90g are electrostatically charged with each other. Be adsorbed. As a result, the drive coupling 90 and the driven coupling 63 are connected.

(Example 3)
The third embodiment will be described with reference to FIGS. 13 and 14.
FIG. 13 is a schematic cross-sectional view of the driving force transmission mechanism according to the third embodiment, showing a state before the driving coupling 90 and the driven coupling 63 are connected. FIG. 14 is a schematic cross-sectional view of the driving force transmission mechanism according to the third embodiment, showing a state in which the driving coupling 90 and the driven coupling 63 are connected.

As shown in FIGS. 13 and 14, the electrostatic adsorption function unit may be arranged not in the drive coupling 90 but in the driven coupling 63. The electrostatic adsorption function portion 63g has a through hole of Φ4, and the through hole and the fitting hole 63h of Φ4 are aligned with the relative surface 63f2 of the coupling base material 63a to form the above-mentioned conductive double-sided tape or the like. Is fixed by. As described above, when a voltage is applied, dielectric polarization occurs in the electrostatic adsorption function unit 63g, and the drive transmission surface 63c of the electrostatic adsorption function unit 63g and the drive transmission surface 90c of the drive coupling 90 electrostatically attract each other. Will be done. As a result, the drive coupling 90 and the driven coupling 63 are connected.

With the configuration and operation described above, it is possible to achieve the transmission of the drive force without the backlash of the drive transmission coupling. Here, in order to obtain a desired drive transmission force, it is possible to appropriately select the area of the electrostatic adsorption function unit 90 g as a dielectric and the voltage applied to the electrostatic adsorption function unit 90 g. Needless to say.

In this embodiment, the process cartridge in which the cleaning unit and the developing unit are integrally configured has been described, but the configuration of the cartridge that can be attached to and detached from the apparatus main body is not limited to the configuration shown in this embodiment. .. Needless to say, the present invention can be applied to a configuration in which the cleaning unit and the developing unit are independently attached to and detached from the apparatus main body as a cleaning cartridge (drum cartridge) or a developing cartridge.
The present invention can also be effectively applied to an apparatus configuration that employs a cleanerless process that eliminates cleaning blades. It can also be suitably applied to the drive coupling of the developing unit. It can also be suitably applied in a multicolor image forming process. Further, it can be suitably applied as an electric clutch by utilizing the ON / OFF action of the electrostatic adsorption action by ON / OFF of the voltage applied to the coupling.

Unless otherwise specified, the functions, materials, shapes, and relative arrangements of the components described in the present embodiment are not intended to limit the scope of the present invention to those.

(Example 4)
The configuration of the drive transmission coupling according to the fourth embodiment will be described in detail with reference to FIGS. 15 to 20. 16 and 17 are schematic perspective views showing the configuration of the driven coupling 63 of the cartridge B in this embodiment. FIG. 19 is a schematic perspective view showing the configuration of the drive coupling 90 of the apparatus main body A in this embodiment. FIG. 20 is a schematic cross-sectional view of the driving force transmission mechanism according to the present embodiment, showing a state before the driving coupling 90 and the driven coupling 63 are connected.
The drive transmission coupling of the present invention is composed of a drive coupling 90 provided in the apparatus main body A and a driven coupling 63 provided in the cartridge B.

(Explanation of the configuration of the driven coupling 63 of the cartridge B)
First, the configuration of the driven coupling 63, which is the driven coupling provided in the cartridge B, will be described.
As shown in FIG. 15, a driven coupling 63 as a coupling means is provided at one end in the longitudinal direction of the drum 62 attached to the cartridge B. The driven coupling 63 has a coupling base material 63a. The drum coupling base material 63a is integrally provided with a drive transmission function portion 63b having a diameter of 16 mm and a drum flange function portion 63f. On the tip surface of the drive transmission function unit 63b, a drive transmission surface 63c, which is a second electrode as the drive transmission function unit that comes into contact with the drive coupling 90 provided in the apparatus main body A in a surface configuration, is provided on the drum 62 and the cover. It is provided as a surface extending in a direction orthogonal to the rotation axis of the drive coupling 63.

Further, at the tip of the drive transmission function unit 63b, a driven engagement unit 63h as a drive transmission function unit that engages with the drive coupling 90 provided in the device main body A is provided. The driven engaging portion 63h is formed in a spline shape consisting of eight teeth extending from the coupling base material 63a on the rotation axis of the drum 62 in the direction opposite to the drum 62, and serves as a centering function portion having a diameter of 5 mm. A core functional surface 63i and a convex portion 63j having an outer diameter of 7 mm are provided. The driven engaging portion 63h is an engaging convex portion with which the driven engaging portion 90h protruding in the direction of the rotation axis engages. The engaging convex portion includes a shaft portion having a centering function surface 63i protruding in the direction of the rotation axis as an outer peripheral surface, and a convex portion 63j as an engaging portion protruding radially outward from the outer surface of the shaft portion. Have. Eight convex portions 63j are provided on the outer peripheral surface of the shaft portion at equal intervals in the circumferential direction, and each protrudes outward in the radial direction at a height of 1 mm from the outer peripheral surface of the shaft portion. Each convex portion 63j includes an engaging surface (second engaging surface) 63j1 that intersects a surface orthogonal to the rotation axis of the driven coupling 63.

(Coupling action of drive transmission coupling)
With reference to FIGS. 17 to 19, the coupling action of the drive transmission coupling accompanying the mounting of the cartridge B on the apparatus main body A will be described.
With the above-described configuration, as shown in FIG. 18, when the opening / closing door 13 of the device main body A is opened, the drive coupling 90 provided in the device main body A moves in the direction away from the cartridge B in the direction of its rotation axis. ..

Next, the cartridge B is attached to the apparatus main body A. Then, by closing the opening / closing door 13, the drive coupling 90 that had previously moved to the retracted position moves to the cartridge B side with rotation. Due to the movement of the drive coupling 90 accompanied by rotation, the spline shape of the drive engagement portion 90h of the drive coupling 90 and the driven engagement portion 63h of the cartridge B are in phase with each other, and the drive coupling 90 is moved to the driven coupling 63. Move further to the side. Then, the centering functional surface 90i of the drive engaging portion 90h and the centered functional surface 63i of the driven engaging portion 63h are fitted, and the concave portion 90j of the driving engaging portion 90h and the convex portion of the driven engaging portion 63h are fitted. The portion 63j engages. Each recess 90j includes an engaging surface (first engaging surface) 90j1 that intersects a surface orthogonal to the rotation axis of the drive coupling 90. After that, the drive transmission surface 90c and the driven transmission surface 63c come into contact with each other. At this time, the centered functional surface 63i of the driven engaging portion 63h is fitted with the centered functional surface 90i of the drive coupling 90 to define the rotation center of the drum 62 with respect to the drive coupling 90, and further. When the convex portion 63j engages with the concave portion 90j, it functions as a drive transmission function portion. Here, the state in which the convex portion 63j of the driven engaging portion 63h engages with the concave portion 90j of the drive coupling 90 refers to a surface orthogonal to the rotation axis (rotation axis) of the drum 62 and the driven coupling 63. When the intersecting surfaces (engaging surfaces 90j1 and 63j1) come into contact with each other, the driving force can be transmitted from the coupling 90 to the driven coupling 63. The drive transmission surface 90c is a surface orthogonal to the rotation axis of the drive coupling 90.

(Driving transmission action of coupling)
The drive transmission action of the drive transmission coupling accompanying the printing operation will be described with reference to FIGS. 15 and 17 to 19.
As shown in FIG. 1, the cartridge B mounted on the apparatus main body A has the drive engaging portion 93h of the drive coupling 90 and the driven coupling as the drive transmission function portion due to the closing operation of the opening / closing door 13 described above. 63 The driven engaging portion 63h is engaged. Based on the print start signal, the motor 95 provided in the apparatus main body A is driven, and the large gear 97 is driven via the small gear 96. Further, in conjunction with the drive of the large gear 97, the drive coupling 90 integrally configured with the large gear 97 is driven. Then, as the drive transmission function unit, the drive coupling is formed by engaging (contacting) the engaging surface 90j1 of the concave portion 90j of the driving side coupling 90 with the engaging surface 63j1 of the convex portion 63j of the driven coupling 63. The driven coupling 63 rotates with the rotation of 90, and the driving force is transmitted to the photoconductor drum 62. Actually, the drive engaging portion 93h of the drive coupling 90 and the driven engaging portion 63h of the driven coupling 63 were engaged to obtain a drive transmission torque of about 1.6 kgfcm.

At the same time, the controller 101 provided in the apparatus main body A applies a voltage of -1 kv from the high-voltage power supply 100 to the drive transmission coupling via the power supply contact 98.
As a result, the coupling base material 90a ⇒ electrostatic adsorption function part 90g as a dielectric layer ⇒ drive transmission surface 90c ⇒ drive transmission surface 63c ⇒ coupling base material 63a ⇒ conductive part on the inner surface of the photosensitive drum 62 ⇒ flange 64 ⇒ drum shaft 78 ⇒ Current flows to the ground through the ground contact 99.

This current flow causes the following phenomenon when compared with the above-mentioned Johnsen-Labeck force generation mechanism. That is, the electric charge applied to the coupling base material 90a as the electrode (one electrode) passes through the electrostatic adsorption function portion 90g as the dielectric layer (dielectric) and has the electrostatic adsorption function as the outermost surface of the dielectric layer. It moves to the drive transmission surface 90c which is the surface of the part 90g. With respect to this charge, the drive transmission surface 63c of the driven coupling 63 as the object to be adsorbed (the other electrode) is charged by electrostatic induction or dielectric polarization. As a result, an electrostatic attraction force is generated between the drive transmission surface 90c and the drive transmission surface 63c. Then, the motor 95 provided in the apparatus main body A is driven, and the large gear 97 is driven via the small gear 96. Along with this operation, the electrostatic attraction force is converted into the frictional force between the drive transmission surface 90c and the drive transmission surface 63c, so that the driven coupling 63 rotates with the rotation of the drive coupling 90, and the drum 62 It is driven.

<Advantages of this example>
In this embodiment, as a driven engaging portion 63h as a convex portion provided on the driven coupling 63 as one coupling member and as a concave portion provided on the drive coupling 90 as the other coupling member. A concave-convex engaging portion is formed by the drive engaging portion 90h of the above. In this concave-convex engaging portion, the driven engaging portion 63h and the driving engaging portion 90h regulate the relative movement of the driven coupling 63 and the drive coupling 90 in the rotational direction of the drive coupling 90. Engage with each other in the direction of rotation. On the other hand, the driven coupling 63 and the driven coupling 90 serve as a dielectric so that the relative movement is restricted by applying a voltage between the drive coupling 90, the electrostatic adsorption function unit 90 g, and the driven coupling 63. They are electrostatically adsorbed to each other via the electrostatic adsorption function unit 90g. In addition to the mechanical connection by the concave-convex engaging portion, by using the connection using the electrostatic adsorption force, it is possible to stably transmit the driving force from the driving coupling 90 to the driven coupling 63 without play. It becomes. That is, in the above-described configuration of the drive engaging portion 90h and the driven engaging portion 63h, it is necessary to provide a gap in the engaging portion from the viewpoint of dimensional error during manufacturing. This gap becomes a backlash component in the rotation direction, and the drive transmission performance of the driven portion such as the photoconductor drum may deteriorate. In this embodiment, since the drive transmission surface 90c and the driven transmission surface 63c are coupled as the drive transmission function unit by a frictional force using an electrostatic attraction force, the drive engagement portion 90h and the driven engagement portion described above are engaged with each other. It is possible to eliminate backlash in the rotation direction of the portion 63h. Further, in this embodiment, by having two types of drive transmission units, a drive transmission unit using engagement and a drive transmission unit using frictional force using electrostatic attraction, the main body device A to the cartridge B are provided. It is possible to transmit a larger driving force. Therefore, the driving force without backlash in the rotation direction can be transmitted from the driving coupling 90 of the apparatus main body A to the photoconductor drum 62 connected to the driven coupling 63 of the cartridge B. With the configuration and operation described above, the backlash of the drive coupling can be achieved.

Further, the driven engaging portion 63h, which is a convex portion of the concave-convex engaging portion, has a shaft portion protruding in the rotation axis direction and an engaging portion protruding in the radial direction orthogonal to the rotation axis direction from the outer peripheral surface of the shaft portion. It is configured to have a convex portion 63j and the above. Further, the drive engaging portion 90h, which is a concave portion of the concave-convex engaging portion, is recessed in the direction of the rotation axis, and is recessed in the radial direction from the inner peripheral surface of the hole portion and the hole portion into which the shaft portion is fitted. It is configured to have a concave portion 90j as an engaged portion into which the concave convex portion 63j is fitted. As the drive coupling 90 and the driven coupling 63 approach each other in the rotation axis direction when the cartridge B is mounted, the centering function surface 63i, which is the outer peripheral surface of the shaft portion of the driven engagement portion 63h, and the drive engagement portion 90h The centering function surface 90i, which is the inner peripheral surface of the hole, abuts and slides on each other. As a result, a centering function for aligning the rotation center axis of the drive coupling 90 with the rotation center axis of the driven coupling 63 can be obtained. At the same time, the chamfered corner portion of the convex portion 63j, which is the engaging portion of the driven engaging portion 63h, slides with respect to the corner portion of the concave portion 90j and fits into the concave portion 90j. As a result, a function of adjusting the rotation phase between the drive coupling 90 and the driven coupling 63 can be obtained. As a result, the convex portion 63j and the concave portion 90j are arranged so as to coincide with each other in the rotation axis direction and engage with each other in the circumferential direction, and the relative movement in the rotation direction between the drive coupling 90 and the driven coupling 63 Can be regulated.

In this embodiment, the engagement configuration and the alignment configuration (centering function portion that defines the rotation center) of the drive coupling 90 and the driven coupling 63 by the driven engagement portion 63h and the drive engagement portion 90h are set. It is arranged in the central part of the circular electrostatic adsorption joint surface, that is, in the region near the central axis of rotation. The lossless transmission of rotational driving force on a circular joint surface perpendicular to the rotation axis means that the joint surfaces do not shift from each other in the circumferential direction, that is, the drive coupling 90 and the driven coupling 63 in the rotation direction. Relative movement to and from is regulated. What is important in suppressing the displacement of the joint surface in the circumferential direction is the suction force in the region on the outer peripheral side away from the center of the rotation axis where the joint area becomes relatively wide. As shown in the equation (1), the transferable torque T is determined by the integral of the product of the radial position r and the electrostatic attraction force P (r) at that position. That is, the electrostatic adsorption force on the outer side (larger r) in the radial direction contributes more to the transmissible torque than on the inner side (small r) in the radial direction of the electrostatic adsorption function portion. Therefore, if a sufficient suction force can be secured in the region on the outer peripheral side, it is possible to transmit the rotation driving force without loss in the region near the center of the rotation axis without exerting the suction force. In this embodiment, the electrostatic adsorption joint surface of the drive coupling 90, the driven coupling 63, and the electrostatic adsorption function portion 90 g is an annular surface having an inner diameter and an outer diameter, and the rotation center portion inside the joint surface. A concave-convex engaging portion formed by the driven engaging portion 63h and the driven engaging portion 90h is arranged therein. Further, the driven engaging portion 63h is made of a separate member from the driven coupling 63, and is fixed by being fitted into a fitting hole recessed in the rotation axis direction provided in the driven coupling 63. It is composed of insulating members. Further, the outer diameter of the electrostatic adsorption function portion 90 g is expanded to the outer diameter side with respect to the joint region (joint surface) with each coupling. That is, the outer diameter of the surface facing each coupling in the electrostatic adsorption function portion 90g is larger than the outer diameter of the bonding region (bonding surface) with each coupling. As a result, it is possible to reliably align the drive coupling 90 and the driven coupling 63 and to generate a stable electrostatic adsorption force without leakage, and it is possible to realize a lossless drive force transmission.

Here, in this embodiment, the electrostatic adsorption function portion 90 g as the dielectric layer is arranged in the drive coupling 90, but it may be arranged in the driven coupling 63. Further, the electrostatic adsorption function portion as the dielectric layer may be arranged on both the drive coupling 90 and the driven coupling 63.
Further, in this embodiment, the process cartridge in which the cleaning unit and the developing unit are integrally configured has been described, but the configuration of the cartridge that can be attached to and detached from the apparatus main body is not limited to the configuration shown in this embodiment. .. Needless to say, the present invention can be applied to a configuration in which the cleaning unit and the developing unit are independently attached to and detached from the apparatus main body as a cleaning cartridge (drum cartridge) or a developing cartridge.

In this embodiment, when the opening / closing door 13 is closed, the device main body A drive coupling 90 moves in a direction approaching the driven coupling 63 provided on the cartridge B with rotation, and the couplings are engaged with each other. The configuration to be combined has been illustrated, but the configuration is not limited to this configuration. For example, in conjunction with the drive of the motor 95 of the device main body A, the large gear 97 moves to the process cartridge B side with rotation by the action of the hasba gears configured in the small gear 96 and the large gear 97, and the drive cup is used. The ring 90 and the driven coupling 63 may be engaged with each other.

Here, in the present embodiment, as the drive transmission function unit, the drive engaging portion 90h of the main body device A is configured in a concave shape, and the driven engaging portion 63h of the cartridge B is configured in a convex shape, but the present invention is not limited to this configuration. .. For example, the drive engaging portion 90h of the main body device A may be configured with an insulating convex shape, and the driven engaging portion 63h of the cartridge B may be configured with a conductive concave shape.

(Modification 2)
The second modification has a configuration in which the adsorption principle of the drive transmission surface 63c and the drive coupling 90 of the fourth embodiment is changed from electrostatic adsorption to magnetic adsorption. Specifically, the drive transmission surface 63c of the fourth embodiment is configured as the surface of the magnet portion, and the drive transmission surface 90c is configured as the surface of the magnetic material. Even with this configuration, the same effect as in Example 4 can be obtained.

(Example 5)
The fifth embodiment will be described with reference to FIGS. 21 and 22. In the fourth embodiment, as the drive transmission function unit, a configuration in which the drive engaging portion 90h of the main body device A and the driven engaging portion 63h of the cartridge B are provided near the center of each coupling is illustrated. Not limited. That is, in this embodiment, the concave-convex engaging portion composed of the drive engaging portion 90h and the driven engaging portion 63h is arranged near the rotation axis in the region where the drive coupling 90 and the coupling 63 face each other, and the concave-convex engagement portion is engaged. A connecting portion by electrostatic attraction was arranged in the outer peripheral region surrounding the joint portion. On the other hand, as shown in FIGS. 21 and 22, the arrangement relationship between the mechanical connecting portion by the concave-convex engaging portion and the connecting portion using the electrostatic adsorption force may be reversed. That is, a concave portion recessed in the rotation axis direction is provided in the rotation center portion of the drive coupling 90 in the region facing the driven coupling 63, the bottom surface of the concave portion is a circular electrostatic suction surface 90c, and the outer periphery of the concave portion is uneven. A drive engaging portion 90h constituting the engaging portion is provided. The drive engaging portion 90h is composed of an insulating member that is a separate member from the drive coupling 90. On the other hand, a convex portion protruding in the direction of the rotation axis is provided in the rotation center portion of the driven coupling 63 in the region facing the drive coupling 90, and an electrostatic adsorption function portion which is a dielectric is adhesively fixed to the tip of the convex portion. A circular electrostatic suction surface 63c is formed. Then, a driven engaging portion 63h forming the concave-convex engaging portion is provided on the outer periphery of the convex portion. The driven engaging portion 63h is provided integrally with the coupling base material 63a of the driven coupling 63. The couplings may be connected to each other by engaging the driven engaging portion 90h and the driven engaging portion 63h. In this configuration as well, as in the above-described embodiment, the alignment functional surface 90i of the drive engaging portion 90h and the alignment functional surface 63i of the driven engagement portion 63h are fitted, and the concave portion 90j and the convex portion 63j are fitted. Engage and come into contact with the engaging surfaces 90j1 and 63j1. After that, the drive transmission surface 90c and the driven transmission surface 63c come into contact with each other.

(others)
The present invention can also be effectively applied to an apparatus configuration that employs a cleanerless process that eliminates cleaning blades. It can also be suitably applied to the drive coupling of the developing unit. It can also be suitably applied in a multicolor image forming process. Unless otherwise specified, the functions, materials, shapes, and relative arrangements of the components described in the present embodiment are not intended to limit the scope of the present invention to those.

(Modification example 3)
The third modification is a configuration in which the adsorption principle of the drive transmission surface 63c and the drive coupling 90 of the fifth embodiment is changed from electrostatic adsorption to magnetic adsorption. Specifically, the drive transmission surface 63c of the fifth embodiment is configured as the surface of the magnet portion, and the drive transmission surface 90c is configured as the surface of the magnetic material. Even with this configuration, the same effect as in Example 5 can be obtained.

(Example 6)
The sixth embodiment will be described with reference to FIGS. 23 to 29.
<Overview of drive transmission coupling>
The configuration of the drive transmission coupling according to the sixth embodiment will be described in detail with reference to FIG. The drive transmission coupling of the present invention is composed of a drive coupling 90 provided in the apparatus main body A and a driven coupling 63 provided in the cartridge B. First, the configuration of the driven coupling 63 provided in the cartridge B will be described. As shown in FIG. 23, a driven coupling 63 as a coupling means is provided at one end in the longitudinal direction of the photosensitive drum 62 mounted inside the cartridge B. The driven coupling 63 has a coupling base material 63a. The coupling base material 63a is integrally provided with a drive transmission function portion 63b having a diameter of 16 mm and a drum flange function portion 63f. Then, an electrostatic adsorption function unit 63e as a dielectric that attracts the end surfaces of the couplings is fixed to the tip surface of the drive transmission function unit 63b, that is, the opposite region between the drive coupling 90 and the driven coupling 63. There is. A conductive double-sided tape (not shown) was used for this fixing, but the bonding method may be appropriately selected according to the required adhesive strength. The surface roughness (center line average roughness) of the electrostatic adsorption function unit 63e was adjusted to Ra = 0.2 μm. The surface roughness Ra of the coupling member and the dielectric material described later is, for example, the center line average roughness measured using a surface roughness measuring instrument based on the JIS surface roughness "JIS B 0601 (2001)". Can be specified by.

The drum flange function portion 63f is provided with a fitting portion 63f1 in the axial direction of the photosensitive drum 62 and in the direction opposite to the drive transmission function portion 63b. Then, when the drum flange functional portion 63f is attached to the photosensitive drum 62, the fitting portion 63f1 is fitted to the inner surface of the photosensitive drum 62 and is crimped to fix the drum flange functional portion 63f and the photosensitive drum 62. Here, the method of fixing the drum flange functional portion 63f is not limited to caulking, and can be appropriately selected such as adhesion.

Next, the material of each constituent member will be described. As the material of the coupling base material 63a, conductive aluminum was used. However, the material of the coupling base material 63a is not limited to the aluminum, but is conductive such as metals such as iron and copper, conductive ceramics, and conductive resins generally used in process cartridges. Anything that has sex may be used. Specifically, a molded product using a product obtained by adding the above-mentioned conductive agent to polyacetal, polyester, epoxy resin or the like may be used. As a guide, the volume resistivity is 1 × 10 ¹⁰ Ωcm or less.

Further, as the material of the electrostatic adsorption function unit 63e, a medium resistance polyimide functioning as a dielectric was used. The medium-resistance polyimide was produced by dispersing carbon black for resistivity adjustment in a liquid polyimide varnish, pouring the liquid varnish into a mold, and removing the solvent by heating. The volume resistivity and thickness of the electrostatic adsorption function unit 90e will be described later. Here, the material of the electrostatic adsorption function unit 63e is not particularly limited, such as polyacetal, polyvinyl fluoride den, and urethane rubber, and the conductive agent for adjusting the volume resistivity is also an electron conductive agent or an ion conductive agent. The agent and the like can be appropriately selected. Examples of the electronic conductive agent include carbon black and graphite exhibiting electron conductivity; oxides such as tin oxide; metals such as copper and silver; conductive particles obtained by coating the particle surface with an oxide or metal to impart conductivity. Can be mentioned. Examples of the ionic conductive agent include quaternary ammonium salts exhibiting ionic conductivity and ionic conductive agents having ion exchange properties such as sulfonates. The dielectric defined in the present invention is a substance that does not easily pass an electric current and generates dielectric polarization when an electric field is applied, and has a resistance component and a dielectric component in a conducting mechanism such as an insulator containing conductive particles. This also includes substances with. Here, the volumetric resistance of the electrostatic adsorption function unit 63e described above was measured at an applied voltage of 1 kV using a Mitsubishi Chemical Analytical High Restor UP MCP-HT450 type and a ring probe: UR.

By selecting the above configuration and material, the driven coupling 63 is electrically conductive with the photosensitive drum 62, and when the cartridge B is mounted on the device main body A, the device main body is passed through the drum shaft 78. It is electrically connected to the ground side of A.

<Configuration of electrostatic adsorption function to reduce power consumption>
Next, the configuration of the electrostatic adsorption function unit 63e for reducing power consumption, which is the basis of the present invention, will be described in detail. First, with reference to FIG. 26, the electrostatic adsorption force, the transferable torque, and the power consumption when the electrostatic resistivity and the thickness do not have a distribution will be described as the electrostatic adsorption function unit 63e. FIG. 26A is a diagram showing a state before the drive transmission function unit 90b and the electrostatic adsorption function unit 63e are coupled. In FIG. 26A, the position in the radial direction from the center of rotation of the electrostatic adsorption function unit 63e is defined as r. FIG. 26B is a diagram showing the distribution of the volume resistivity with respect to the radial position r. As described above, in this example, the volume resistivity is constant. The material of the electrostatic adsorption function unit 63e is the ^{same as the volume resistivity of 1 × 10 11} Ωcm used in FIG. 26, but when the applied voltage is 400 V, it is converted into the volume resistivity of 2.8 ×. a 10 ⁸ Ωcm.

When the volume resistivity of the electrostatic adsorption function unit 63e is set to be constant in this way, as shown in FIG. 26 (c), the electrostatic adsorption force does not have a distribution with respect to the radial position r, and a constant value is obtained. show. When this electrostatic adsorption force is put into the equation (2), the transmissible torque is calculated to be 0.1 Nm. At this time, in the formula (2), the diameter D = 16 mm and the friction coefficient μ = 0.3 of the electrostatic adsorption function unit 63e. Further, as shown in FIG. 26D, when the volume resistivity is constant, the power consumption does not have a distribution depending on the radial position r and shows a constant value. By integrating this power distribution, the total power consumption was calculated, and in this case, the power consumption was 0.16 W. The power distribution in FIG. 26 (d) is a calculated value obtained from the volume resistivity distribution in FIG. 26 (a), and the integrated value of 0.16 W coincides with the actually measured value shown in FIG. 26. As shown above, when the electrostatic adsorption function unit 63e has a constant volume resistivity and a constant thickness, the power consumption is 0.16 W in order to obtain a transmissible torque of 0.1 Nm.

Next, with reference to FIG. 27, the power consumption when the volume resistivity of the electrostatic adsorption function unit 63e according to this embodiment is distributed will be described. As shown in the equation (1), the transferable torque T is determined by the integral of the product of the radial position r and the electrostatic attraction force P (r) at that position. Therefore, the electrostatic attraction force on the outer side (r is large) (outer peripheral region) in the radial direction greatly contributes to the transmittable torque than on the inner side (small r) (central region) in the radial direction of the electrostatic adsorption function unit 63e. Utilizing this idea, in the present invention, it is possible to reduce the power consumption as a whole by increasing the electrostatic adsorption force acting on the outer side in the radial direction of the electrostatic adsorption function unit 63e. Specifically, particles such as carbon black contained in the medium-resistance polyimide or the like forming the electrostatic adsorption function unit 63e for resistance adjustment are placed in the radial direction from the central region near the center of the rotation axis of the electrostatic adsorption function unit 63e. The particles are distributed so that the particle density becomes denser toward the outer outer peripheral region. By doing so, as shown in FIG. 27 (b), the volume resistivity can be reduced as the radial position r becomes larger without changing the shape. With this configuration, as shown in FIG. 27 (c), the electrostatic adsorption force becomes large at the position where the radial position r is large. When the transferable torque is calculated according to the equation (1) from the distribution of the electrostatic attraction force shown in FIG. 27 (c), it is 0.1 Nm as in FIG. 26. Further, when the power distribution is calculated from the volume resistivity distribution in FIG. 27 (b), it becomes as shown in FIG. 27 (d). As shown in FIG. 27 (d), the power distribution also increases at a position where the radial position r is large. The total power consumption is calculated by integrating this power distribution, and in this case, the power consumption is 0.13 W.

Here, FIG. 26 is compared with FIG. 27 according to this embodiment. As shown in FIG. 26, when the volume resistivity was constant, the transferable torque was 0.1 Nm and the power consumption was 0.16 W. Further, as shown in FIG. 27, when the volume resistivity is distributed without changing the shape and the electrostatic attraction force is strengthened on the outer side in the radial direction, the transferable torque is 0.1 Nm and the power consumption is 0.13 W. there were. That is, according to the present invention, the power consumption can be reduced by 0.16-0.13 = 0.03 W, and the ratio can be reduced by 0.03 / 0.16 ≈19%.

Next, with reference to FIG. 28, another configuration for reducing power consumption will be described. As shown in FIG. 28 (a), in order to increase the electrostatic adsorption force acting on the outer side in the radial direction of the electrostatic adsorption function portion 63e, the thickness is distributed here. Specifically, as shown in FIG. 28 (b), as the radial position r increases, the thickness is reduced so that it becomes bowl-shaped when viewed from the direction orthogonal to the rotation axis direction. .. With this configuration, the resistance value (volume resistivity) increases near the center where the thickness is large in the direction of the rotation axis, making it difficult for current to flow, and the thickness decreases as the radial position r increases. Therefore, the resistance value (volume resistivity) becomes low, and the current easily flows. Then, as shown in FIG. 28 (c), the electrostatic adsorption force increases at a position where the radial position r is large. When the transferable torque is calculated according to the equation (1) from the distribution of the electrostatic adsorption force shown in FIG. 28 (c), it is 0.1 Nm as in FIG. 26. Further, when the power distribution is calculated from the volume resistivity distribution in FIG. 28 (b), it becomes as shown in FIG. 28 (d). As shown in FIG. 28 (d), the power distribution also increases at a position where the radial position r is large. The total power consumption is calculated by integrating this power distribution, and in this case, the power consumption is 0.15 W. When the volumetric resistance and thickness of the electrostatic adsorption function part are not distributed, the power consumption is 0.16 W, so the reduction amount is 0.16-0.15 = 0.01 W, and the ratio is 0. It is possible to reduce by 0.01 / 0.16 ≈ 6%.

As described above, in this embodiment, a medium-resistance polyimide sheet is used as the electrostatic adsorption function unit 63e. A medium-resistance polyimide sheet is manufactured by dispersing carbon black for resistance adjustment in a polyimide liquid varnish, pouring it into a mold, heating it, and removing the solvent. Therefore, in order to give the polyimide sheet a thickness distribution as shown in FIG. 28 (a), a bowl-shaped processed mold may be used.

Next, with reference to FIG. 29, another configuration for reducing power consumption will be described. FIG. 29 is a diagram in which the electrostatic adsorption function unit 63e is provided with the micropores 63h. Here, in order to increase the electrostatic adsorption force acting on the electrostatic adsorption function unit 63e on the outer side in the radial direction, the density of the micropores 63h is increased in the central portion and decreased on the outer side. That is, a plurality of micropores 63h are centrally provided near the center of the rotation axis of the electrostatic adsorption function unit 63e, and the number of micropores 63h is reduced toward the outside in the radial direction. Since the electrostatic adsorption force increases in proportion to the contact area between the electrostatic adsorption function unit 63e and the drive transmission unit 90b, the electrostatic adsorption function unit 63e is made by reducing the density of the micropores 63h outside the central portion. The contact area between the electrostatic adsorption function unit 63e and the drive transmission unit 90b on the outside of the is increased. Further, air will enter the portion where the micropores are opened. Since air has high insulating properties, the resistance value (volume resistivity) is larger in the central part where micropores are concentrated than in the radial outside, and the resistance value (volume resistivity) is larger in the radial outside than in the center part. Becomes smaller. As a result, the electrostatic adsorption force acting on the outside of the electrostatic adsorption function unit 63e becomes large. The diameter of the micropores 63h is preferably smaller than the film thickness of the electrostatic adsorption function portion 63e. For example, when the film thickness is 75 μm, the diameter of the micropores 63h may be about 10 to 50 μm. good.

Further, in order to impart the micropores 63h to the electrostatic adsorption function portion 63e, a convex circular boss is provided in the mold for molding the polyimide sheet described above, and after the sheet is molded, post-processing such as laser irradiation is performed. It may be formed. Further, for the purpose of preventing discharge between the drive transmission function unit 90b on the drive side and the drive transmission function unit 63b on the non-drive side, the micropore 63h does not penetrate the electrostatic adsorption function unit 63e and is half-cut. You may. At this time, it is preferable to install the electrostatic adsorption function unit 63e so that the concave surface of the microhole 63h is in contact with the drive transmission function unit 90b on the drive side. Further, the same power consumption reduction effect can be obtained by controlling the surface roughness of the electrostatic adsorption function unit 63e instead of providing the micropores 63h. Specifically, the surface roughness of the central portion of the electrostatic adsorption function portion 63e is increased to about Ra = 1 μm, and the outer surface roughness is decreased to about Ra = 0.2 μm. By doing so, the contact area between the electrostatic adsorption function unit 63e and the drive transmission function unit 90b becomes smaller outside the electrostatic adsorption function unit 63e, and as a result, electrostatic electricity occurs outside the electrostatic adsorption function unit 63e. The adsorption power is increased, and it is possible to reduce the power consumption as a whole. The amount of reduction is the same as in FIG. 28 and will be omitted.

With the configuration and operation described above, when the drive coupling 90 and the driven side coupling 63 are joined, it is possible to secure a sufficient electrostatic attraction force in the outer peripheral region rather than the region near the center of the rotation axis. can. Then, in the region near the center of the rotation axis, the rotation driving force can be transmitted even if the electrostatic attraction force does not work. That is, the relative movement of the drive coupling 90 and the driven coupling 63 in the rotation direction can be regulated. Furthermore, it becomes achievable to reduce power consumption in the drive transmission coupling that can realize rattling. In this embodiment, a process cartridge in which a cleaner unit and a developing unit are integrated is described. However, it can also be applied in a configuration in which the cleaner unit and the developing unit are independently attached to and detached from the image forming apparatus main body as a cleaner cartridge or a developing cartridge. Further, this configuration can be suitably applied to a cleanerless process in which the above-mentioned cleaner blade is abolished, and a drive coupling of a developing unit. It can also be suitably applied in a multicolor image forming process.

Here, in this embodiment, the electrostatic adsorption function portion 63e as the dielectric layer is arranged in the driven coupling 63, but it may be arranged in the drive coupling 90. Further, the electrostatic adsorption function portion as the dielectric layer may be arranged on both the drive coupling 90 and the driven coupling 63. Further, it can be suitably applied as an electric clutch by utilizing the ON / OFF action of the electrostatic adsorption action by ON / OFF of the voltage applied to the coupling.

(Modification example 4)
The modified example 4 has a configuration in which the adsorption principle of the electrostatic adsorption function unit 63e and the drive coupling 90 of the sixth embodiment is changed from electrostatic adsorption to magnetic adsorption. Specifically, the electrostatic attraction function unit 63e of Example 6 was changed to a magnetic attraction function unit 63e which is a magnet, and the drive transmission surface 90b was changed to the surface of a magnetic material. Then, the magnetic adsorption function portion 63e is provided with the micropores 63h so as to increase the number of the micropores 63h toward the inside in the radial direction. According to this configuration, the magnetic attraction function unit 63e is provided on the radial outer side (r is large) (outer region), which greatly contributes to the transmittable torque as compared with the radial inner side (r is small) (central region). There is. Therefore, the volume of the magnetic adsorption function portion 63e arranged inside in the radial direction can be reduced, and the volume of the entire magnetic adsorption function portion 63e can be reduced. Therefore, it is possible to reduce the cost and weight of the driven coupling 63 and the cartridge B while suppressing the decrease in the transmittable torque.

(Example 7)
Example 7 of the present invention will be described with reference to FIGS. 30 to 34. Similar to the sixth embodiment, this embodiment describes the structure of the electrostatic adsorption function unit for the purpose of reducing the power consumption of the drive transmission coupling. In Example 6, since the volume resistivity and the thickness distribution of the electrostatic adsorption functional portion are gently changed, it may be difficult to manufacture the electrostatic adsorption functional portion. Therefore, in this embodiment, a configuration for facilitating the manufacture of the electrostatic adsorption function unit while reducing the power consumption of the drive transmission coupling will be described. The configuration and operation of the image forming apparatus, the cleaner unit, the developing unit, the process cartridge, and the like are the same as those in the sixth embodiment. In this embodiment, only the differences from the sixth embodiment will be described, and detailed description of other parts will be omitted.

FIG. 30 is a diagram showing the configuration of the drive transmission coupling according to the seventh embodiment. In this embodiment, the volume resistivity and the thickness of the electrostatic adsorption function unit 63e are changed stepwise. FIG. 30A is a diagram in which a medium-resistance electrostatic adsorption function unit 63e and a high-resistance electrostatic adsorption function unit 63i are combined. Here, as the electrostatic adsorption function part, a polyimide sheet was used as in Example 6. The volume resistivity of the polyimide sheet can be adjusted by controlling the amount of carbon black to be dispersed. That is, the medium-resistance electrostatic adsorption function unit 63e has a larger amount of carbon black dispersed inside the polyimide sheet than the high-resistance electrostatic adsorption function unit 63i. Further, in order to integrally form the medium-resistance electrostatic adsorption function unit 63e and the high-resistance electrostatic adsorption function unit 63i as shown in FIG. 30 (a), the electrostatic adsorption function units in their respective shapes may be bonded together. .. It is also possible to pour two types of liquid varnishes into a molding die and mold them in two colors. ^{Here, a polyimide sheet having a volume resistivity of 5 × 10 10} Ωcm is used as the medium resistance electrostatic adsorption function unit 63e, and a polyimide sheet having a volume resistivity of 1 × 10 ¹⁵ Ωcm is used as the high resistance electrostatic adsorption function unit 63i. board.

FIG. 30B is a diagram showing the distribution of volume resistivity with respect to the radial position r. As described above, the volume resistivity changes depending on the applied voltage, but the figure shown in FIG. 30B is the volume resistivity when a voltage of −400 V is applied to the drive transmission function unit 90b. FIG. 30 (c) is a diagram showing the electrostatic adsorption force when configured in this way. Looking at FIG. 30 (c), it can be seen that the electrostatic adsorption force hardly works in the high resistance electrostatic adsorption function unit 63i, and the electrostatic adsorption force works in the medium resistance electrostatic adsorption function unit 63e. When this electrostatic adsorption force is integrated according to the equation (1), a transmission torque of 0.1 Nm is obtained as in Example 1. At this time, it was calculated assuming that the outer diameter D of the electrostatic adsorption function unit 63e of medium resistance = 16 mm, the outer diameter D of the electrostatic adsorption function unit 63i of high resistance = 3 mm, and the friction coefficient μ = 0.3.

FIG. 30 (d) is a power distribution calculated from the volume resistivity distribution of FIG. 30 (b). As shown in FIG. 30 (d), the electric power is increased in the electrostatic adsorption function unit 63e of the medium resistance. The total power consumption is calculated by integrating this power distribution, and in this case, the power consumption is 0.15 W. In Example 1, when the volume resistivity and the thickness of the electrostatic adsorption function unit 63e were constant, the transferable torque was 0.1 Nm and the power consumption was 0.16 W. On the other hand, when the volume resistivity is changed between the central portion and the outer peripheral portion and the electrostatic attraction force at the outer peripheral portion is strengthened as in this embodiment, the transferable torque is 0.1 Nm and the power consumption is 0.15 W. there were. That is, according to the present invention, the power consumption can be reduced by 0.16-0.15 = 0.01 W, and the ratio is 0.01 / 0.
.. It is possible to reduce by 16≈6%.

Next, another configuration of the seventh embodiment will be described with reference to FIG. In FIG. 31, a circular hole (through hole) 63j is provided in the central portion of the electrostatic adsorption function portion 63e (the region including the rotation axis of the driven coupling 63 when viewed in the direction of the rotation axis of the driven coupling 63). It is a figure which shows the structure. That is, the electrostatic adsorption function portion 63e has a so-called donut shape, which is not provided in the central portion when viewed in the direction of the rotation axis of the driven coupling 63, but is provided in a region surrounding the central portion. By doing so, the highly insulating air enters the central portion where the circular hole 63j is provided, so that the resistance value (volume resistivity) becomes large. Therefore, as in FIG. 30, the electrostatic attraction force acting outside the rotation center of the drive transmission coupling becomes large, and it becomes possible to reduce the power consumption as a whole. The effect of the reduction is omitted because it is almost the same as the value described in FIG. In addition, in order to provide the circular hole 63j in the central portion of the electrostatic adsorption function portion 63e as described above, a circular convex shape may be provided in the molding mold of the polyimide sheet, or a polyimide having no circular hole 63j may be provided. It can be manufactured by post-processing the sheet. Further, in order to avoid discharge of the drive transmission function unit 90b on the drive side and the drive transmission function unit 63b on the non-drive side, the circular hole 63j can be cut out halfway without penetrating the electrostatic suction function unit 63e. be. In this case, it is preferable to attach the concave surface formed at the center of the electrostatic adsorption function unit 63e in the direction facing the drive transmission function unit 90b on the drive side.

According to the configuration and operation described above, when the drive coupling 90 and the driven side coupling 63 are joined, sufficient static electricity is applied in the outer peripheral region rather than the central region near the center of the rotation axis, as in the first embodiment. Adsorption power can be secured. Then, in the region near the center of the rotation axis, the rotation driving force can be transmitted even if the electrostatic attraction force does not work. That is, the relative movement of the drive coupling 90 and the driven coupling 63 in the rotation direction can be regulated. Further, it becomes achievable to reduce the power consumption in the drive coupling that can realize the backlash. Further, by changing the volume resistivity and the thickness of the electrostatic adsorption function portion stepwise, the production becomes easier.

(Modification 5)
The modified example 5 has a configuration in which the suction principle of the electrostatic suction function unit 63e and the drive coupling 90 of the seventh embodiment is changed from electrostatic suction to magnetic suction. Specifically, the electrostatic adsorption function unit 63e of Example 7 was changed to the magnetic adsorption function unit 63e, and the drive transmission surface 90b was changed to the surface of the magnetic material. Then, similarly to the configuration of FIG. 31, a circular hole 63i is provided in the central portion of the magnetic adsorption function portion 63e in a direction orthogonal to the rotation axis direction of the driven side coupling 63. Therefore, the volume of the magnet portion 63e arranged inside in the radial direction can be reduced, and the volume of the entire magnetic attraction function portion 63e can be reduced. Therefore, the cost and / or weight of the driven coupling 63 and the cartridge B can be reduced while suppressing a decrease in the transmittable torque.

(Example 8)
Example 8 of the present invention will be described. In this embodiment, in addition to the purpose of reducing the power consumption of the drive transmission coupling, the positioning of the drive side coupling (drive coupling 90) and the non-drive side coupling (driven coupling 63) is performed with high accuracy. It describes the structure of. In this embodiment as well, the configurations and operations of the image forming apparatus, the cleaner unit, the developing unit, the process cartridge, and the like are the same as those in the first embodiment. In this embodiment, only the differences from the sixth and seventh embodiments will be described, and detailed description of other parts will be omitted. As described in FIG. 33, the position of the cartridge B is determined by the positioning unit 80 when it is mounted on the apparatus main body A. However, when the distance between the positioning unit 80 and the drive coupling is long, the drive coupling 90 and the driven coupling 63 are misaligned due to factors such as manufacturing errors, and are not sufficiently attracted or are rotationally driven. Large eccentric movements may occur. Such a drive defect causes an image defect.

Therefore, in this embodiment, the drive coupling is provided with a mechanism for positioning the drive side coupling and the non-drive side coupling. This configuration will be described with reference to FIGS. 32, 33, and 34. FIG. 32 is a diagram in which a circular boss 63d (protruding portion) having a diameter of 3 mm and a length of 5 mm is provided at the rotation center position of the electrostatic adsorption function portion 63e. The drive transmission function unit 90b on the drive side is formed with a fitting hole 90d having a diameter of 3 mm and a length of 6 mm so as to face the circular boss 63d on the rotation axis of the photosensitive drum 62. Further, a C chamfer 90e is provided at the entrance of the fitting hole 90d so that the circular boss 63d can easily enter. With this configuration, when the cartridge B is mounted on the apparatus main body A, the positions of the drive side coupling and the non-drive side coupling are determined with high accuracy, and drive transmission can be performed with high accuracy.

Then, by providing the circular boss 63d at the rotation center position of the electrostatic adsorption function unit 63e, the power consumption can be reduced as compared with the case where there is no circular boss. That is, when the circular boss 63d is provided at the center of rotation, the thickness of the electrostatic adsorption function portion 63e increases at the position of the center of rotation. As a result, the electrostatic attraction force of the circumferential portion becomes larger than the electrostatic attraction force at the rotation center position, and the power consumption can be reduced as a whole even with the same transmission torque. Since this reduction amount is the same as the value described in FIG. 30, it is omitted.

Next, the configuration of FIG. 33 will be described. FIG. 33 is a diagram in which the circular boss 63d is formed as a centering member by a member separate from the electrostatic suction function portion 63e. Here, in order to provide the circular boss 63d, a hole having a diameter of 3 mm is provided in the drive transmission function portion 63b of the non-drive side coupling, and a through hole having a diameter of 3 mm is provided in the electrostatic suction function portion 63e. Then, one end of the circular boss 63d is inserted into the hole and firmly fixed with an epoxy adhesive. The other end is inserted into a fitting hole having a diameter of 3 mm and a length of 6 mm provided in the drive transmission function portion 90b. Here, the method of fixing the circular boss 63d to the coupling base material 63a is not limited to an adhesive such as epoxy, and can be appropriately selected such as screwing type or press fitting by knurling. The material of the circular boss 63d may also have a volume resistivity higher than that of the drive transmission function unit 63e, and here, polyacetal, which is an insulating member, is used. Further, as the material of the circular boss, a material having a volume resistivity higher than that of the drive transmission function unit 63e may be appropriately selected, and ceramic, polyester, epoxy resin and the like can be appropriately selected.

Next, the configuration of FIG. 34 will be described. FIG. 34 is a diagram showing a configuration in which a circular boss 63d as a centering member and a drive transmission function unit 63b on the non-drive side are electrically insulated. An insulating bearing 63k is provided in order to electrically insulate the circular boss 63d and the drive transmission function portion 63b on the non-drive side. For the insulating bearing 63k, polyacetal, which is an insulating member, was used. The insulated bearing 63k is firmly fixed to the drive transmission function portion 63b on the non-drive side with an epoxy adhesive. Further, the circular boss 63d is firmly fixed to the insulating bearing 63k with an epoxy adhesive. As the material of the circular boss 63d, a hard material may be appropriately selected so as to be suitable for positioning, and aluminum is used here. Also in this configuration, the materials such as the insulating bearing 63k and the circular boss 63d, or the respective bonding methods can be appropriately selected.

With the configuration described above, by providing the circular boss 63d at the rotation center position of the electrostatic attraction function unit 63e, the drive side coupling and the non-drive side coupling can be positioned with high accuracy, and further, when there is no circular boss. Power consumption can be reduced more than. That is, by providing the circular boss at the center of rotation, the electrostatic attraction force at the circumferential portion becomes larger than the electrostatic attraction force at the center position of rotation, and the power consumption can be reduced as a whole even with the same transmission torque. ..

60 ... Cleaning unit, 61 ... Drum unit (electrophotographic photosensitive member unit), 62 ... Drum (electrophotographic photosensitive drum), 63 ... Driven coupling, 63a ... Coupling base material, 63b ... Drive transmission function unit, 63c ... Drive Transmission surface, 63d ... Circular boss, 63e ... C chamfer, 63f ... Drum flange function part, 63g ... Electrostatic adsorption function part, 90 ... Drive coupling, 90a ... Coupling base material, 90b ... Drive transmission function part, 90c ... Drive transmission surface, 90d ... Mating hole, 90e ... C chamfer, 90f ... Relative surface, 90g ... Electrostatic suction function unit, 95 ... Motor, 96 ... Small gear, 97 ... Large gear, 98 ... Power supply contact, 99 ... Earth Contact, 630g ... Magnet part, 900g ... Magnetic material part, A ... Image forming device body (device body), B ... Process cartridge (cartridge)

Claims (9)

An apparatus main body including a power source and a first coupling member that rotates by a driving force transmitted from the power source.
A cartridge that can be attached to and detached from the main body of the apparatus and includes a second coupling member that rotates by a driving force transmitted from the first coupling member and a rotating body that is connected to the second coupling member. Cartridge and
In the image forming apparatus having
The first coupling member is provided at a hole provided at the center of rotation of the first coupling member and recessed in the direction of the rotation axis of the first coupling member, and provided radially outside the hole from the center of rotation. A first drive transmission surface orthogonal to the rotation axis of the first coupling member is provided.
Said second coupling member includes a protrusion which fits into the protruding the hole in the direction of the axis of rotation of the second coupling member prior Symbol second coupling member provided on the rotation center of the projected from the center of rotation A second drive transmission surface that is provided on the outer side in the radial direction of the portion and is orthogonal to the rotation axis of the second coupling member that is in contact with the first drive transmission surface facing the first drive transmission surface is provided.
At least one of the first drive transmission surface and the second drive transmission surface is formed of a dielectric.
In the apparatus main body, a voltage generated by electrostatic adsorption force that is attracted to each other between the first drive transmission surface and the second drive transmission surface is applied to the first coupling member and the second coupling member. An image forming apparatus including a voltage application unit to be applied between them. The first coupling member is
A drive transmission function unit having the hole and an end face orthogonal to the rotation axis formed on the radial outer side of the hole at the tip in the direction of the rotation axis.
An electrostatic adsorption function composed of the dielectric, which is fixed to the end surface and has a first drive transmission surface and a through hole through which the protrusion is inserted radially inside the first drive transmission surface. Department and
Including
The first aspect of the present invention, wherein the electrostatic adsorption function portion has an outer diameter extending from the rotation center to the outside in the radial direction with respect to the joint surface between the first drive transmission surface and the drive transmission function unit. Image forming device. The second coupling member is
A fitting hole provided inside the second drive transmission surface in the radial direction, and
A circular boss fitted in the fitting hole and
Including
The protrusion is formed by a part of the circular boss protruding from the fitting hole.
The image forming apparatus according to claim 2, wherein the opening edge of the fitting hole has a chamfered tapered shape. The image forming apparatus according to claim 3, wherein the opening edge of the hole has a chamfered tapered shape. The aspect according to any one of claims 1 to 4, wherein the surface roughness (JIS B 0601 (2001)) of the first drive transmission surface and the second drive transmission surface is 0.2 μm or less. Image forming device. Any of claims 1 to 5, wherein the first coupling member and the second coupling member have a volume resistivity of 1 × 10 ^{10 Ωcm or less, except for a portion formed of the dielectric.} The image forming apparatus according to item 1. The first coupling member includes a first engaging surface that intersects a surface orthogonal to the rotation axis of the first coupling member, and the second coupling member is on the rotation axis of the second coupling member. A second engaging surface that intersects the orthogonal surfaces is provided, and a driving force is applied from the first coupling member to the second coupling member in a state where the first engaging surface and the second engaging surface are in contact with each other. The image forming apparatus according to any one of claims 1 to 6, wherein the image forming apparatus is characterized in that. 7. A seventh aspect of the present invention, wherein the second engaging surface is arranged at a position closer to the rotation axis than the second drive transmission surface in a direction orthogonal to the rotation axis of the second coupling member. The image forming apparatus according to the description. 7. A seventh aspect of the present invention, wherein the second engaging surface is arranged at a position farther from the rotation axis than the second drive transmission surface in a direction orthogonal to the rotation axis of the second coupling member. The image forming apparatus according to the description.

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