JP2006078605A - Process cartridge, and image forming apparatus equipped with the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent an idler shaft from vibrating by force transmitted from a main body gear to an idler gear when the main body gear is rotated, in a process cartridge wherein an image carrier and a developing unit are positioned by a positioning member, and connected together, and the idler gear freely rotatably supported by the unit main body of the developing unit via the idler shaft is engaged with a rotating body gear fixed to the shaft of the developing roller of the developing unit, and the main body gear freely rotatably supported by the image forming apparatus body is engaged with the idler gear, then, the rotation of the main body gear is transmitted to the developing roller via the idler gear and the rotating body gear. <P>SOLUTION: The idler shaft 30 which supports the idler gear 31 is held by the positioning member 35, and the vibration of the idler shaft 30 is prevented. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a process cartridge including an image carrier and a rotating body unit, and an image forming apparatus having the process cartridge.

  The process cartridge and the image forming apparatus described above are conventionally known (for example, see Patent Document 1). Such an image forming apparatus is configured as, for example, an electronic copying machine, a printer, a facsimile, or a complex machine thereof, and the rotating body unit is configured as, for example, a developing unit or a cleaning unit. Such a rotator unit has a rotator composed of, for example, a developing roller or a cleaning brush, and the rotator is disposed to face the image carrier, and the shaft of the rotator is rotatably supported by the unit body. Yes.

  In the process cartridge having the above-described configuration, the rotating body gear is fixed to the shaft of the rotating body, and at least one idler gear is rotatably supported on the unit body via the idler shaft, and the rotating body gear is supported via the idler gear. The main body gear is rotatably coupled to the main body of the image forming apparatus, and the rotation of the main body gear is transmitted to the rotary body gear via the idler gear, thereby rotating the rotary body. .

  At that time, when the main body gear rotates, an external force is applied from the main body gear to the idler gear in the direction of the action line deviated by a pressure angle from the common tangent of the main body gear pitch circle and the idler gear pitch circle. For this reason, the idler shaft periodically bends and deforms and vibrates, and the vibration is transmitted to the image carrier, whereby banding occurs in the toner image formed on the image carrier and the image quality deteriorates. There is a fear.

JP 2001-201999 A

  An object of the present invention is to provide a process cartridge capable of preventing or effectively suppressing the occurrence of the above-described problems, and an image forming apparatus including the process cartridge.

  In order to achieve the above object, the present invention comprises an image carrier and a rotator unit, the rotator unit comprising a rotator disposed opposite to the image carrier, and a shaft of the rotator. A rotating unit gear fixed to the shaft of the rotating body, and at least one idler gear rotatably supported on the unit body via an idler shaft, The shafts of the image carrier and the rotating body are positioned and connected to each other by a positioning member, and the rotating body gear is drivingly connected to a main body gear rotatably supported on the main body of the image forming apparatus via the idler gear. A process cartridge in which the rotation of the main body gear is transmitted to the shaft of the rotating body via the idler gear and the rotating body gear, and the rotating body is driven to rotate. External forces which are transmitted to the idler gear from A is to be received in said positioning member, it proposes a process cartridge in which the idler shaft is held in the positioning member (claim 1).

  The process cartridge according to claim 1, wherein the idler shaft is fixed to the unit main body, the idler gear is rotatably supported by the idler shaft, and the axis of the idler gear is supported by the positioning member. It is advantageous if it is positioned in the direction (claim 2).

  The process cartridge according to claim 1 or 2, wherein the unit main body is provided in a sub-reference hole formed in the positioning member so as to prohibit the unit body from rotating about the central axis of the rotating body. It is advantageous that a slave reference pin provided on the main body is fitted and the slave reference pin is fixed to the positioning member.

  Further, in the process cartridge according to claim 3, positioning members respectively disposed on the outer sides of the end portions in the longitudinal direction of the unit main body are connected by the sub reference pin, and the sub reference pin is connected to the rotating body. It is advantageous if it extends substantially parallel to the axis (claim 4).

  5. The process cartridge according to claim 1, wherein the rotating body includes a developing roller, the rotating body unit includes a developing unit, and is carried by the developing roller and conveyed. It is advantageous to form a toner image on the image carrier by the above (claim 5).

  5. The process cartridge according to claim 1, wherein the rotating body is formed of a cleaning brush, and the rotating body unit is configured by a cleaning unit to transfer a toner image formed on the image carrier. It is advantageous to remove the transfer residual toner adhering to the image carrier after the transfer to the material by the action of the cleaning brush.

  Furthermore, in order to achieve the above object, the present invention proposes an image forming apparatus comprising the process cartridge according to any one of claims 1 to 6 (claim 7).

  According to the present invention, during rotation of the main body gear, banding is prevented from occurring in the toner image formed on the image carrier due to an external force exerted from the main body gear to the idler gear, or effectively. Can be suppressed.

  Hereinafter, embodiments of the present invention will be described, and the above-described problems will be clarified more specifically according to the drawings.

  FIG. 1 is a vertical sectional view schematically showing a process cartridge 1 loaded at a predetermined position in the image forming apparatus main body and other process equipment. The process cartridge 1 shown here includes an image carrier 2 made of a drum-shaped photoconductor and a developing unit 3 which is an example of a rotating unit. The image carrier 2 and the developing unit 3 will be described later. It is detachably connected and integrated. The developing unit 3 includes a developing roller 4 which is an example of a rotating body disposed to face the image carrier 2 and a unit main body 6 which rotatably supports a shaft 5 of the developing roller 4. The shaft 5 is formed integrally with the developing roller 4 or is integrally connected to the developing roller 4. The unit body 6 has a developing case 7 in which a dry developer D is accommodated, and the developing roller 4 is disposed in the developing case 7. The unit main body can be configured with only the developing case.

  During the image forming operation, the image carrier 2 is driven to rotate in the counterclockwise direction in FIG. 1, and at this time, the image carrier 2 is charged to a predetermined polarity by the charging roller 8 and the exposure surface (not shown) is exposed on the charged surface. The writing light L emitted from the apparatus is irradiated, whereby an electrostatic latent image is formed on the image carrier 2.

  On the other hand, the developing roller 4 of the developing unit 3 is driven to rotate in the clockwise direction in FIG. 1, and at this time, the developer D is carried and conveyed on the peripheral surface of the developing roller 4 and formed on the image carrier 2 by the developer. The electrostatic latent image is visualized as a toner image. This toner image is fed from a paper feeding device (not shown) and transferred to the transfer material P conveyed in the direction of arrow A by the action of the transfer roller 13. The transfer material P leaves the image carrier 2 and then passes through a fixing device (not shown). At this time, the toner image is fixed to the transfer material P by the action of heat and pressure. It is also possible to transfer the toner image on the image carrier 2 to a transfer material made of an intermediate transfer member, and transfer the toner image on the intermediate transfer member to the final transfer material.

  The transfer residual toner adhering to the image carrier after the toner image is transferred to the transfer material P is removed by the cleaning unit 9. The cleaning unit 9 shown here has a cleaning brush 11 rotatably supported by the unit body 10 and a cleaning blade 12 supported by the unit body 10, and the cleaning brush 11 and the cleaning blade 12 cooperate with each other. By the action, the transfer residual toner on the image carrier is removed. In the cleaning unit 9 of this example, a cleaning case is configured by the unit body 10.

  FIG. 2 is a partial cross-sectional plan view of the process cartridge 1 shown in FIG. In this figure, the charging roller 8 and the cleaning unit 9 shown in FIG. 1 are not shown. 2 indicates the near side of the image forming apparatus main body 14, and R indicates the back side of the image forming apparatus main body 14 (the same applies to FIGS. 3 and 4). FIG. 3 is a perspective view of the process cartridge 1 as viewed from the back side of the image forming apparatus main body.

  As shown in FIG. 2, front and rear flanges 15 and 16 are press-fitted and fixed to respective longitudinal ends of the image carrier 2 formed in a drum shape, and the image carrier is placed in the center holes of both flanges 15 and 16. The body drive shaft 17 is inserted, and the image carrier 2 is supported by the drive shaft 17 via the flanges 15 and 16. The drive shaft 17 is rotatably supported by a back side plate 18 on the back side of the image forming apparatus main body 14 and a support plate 19 fixed to the back side plate 18 via a bearing.

  Further, an opening 21 is formed in the front side plate 20 on the near side of the image forming apparatus main body 14, and a face plate 22 is located in the opening 21, and an end portion on the near side of the drive shaft 17 is located on the face plate 22 via a bearing. It is supported rotatably. The face plate 22 is correctly positioned on the front side plate 20 and is detachably fixed. In this way, the image carrier 2 is correctly positioned with respect to the image forming apparatus main body 14. Reference numeral 50 in FIG. 2 indicates a front door located on the front side of the front plate 20.

  A large number of teeth are formed in the center hole of the flange 16 on the back side, and these teeth mesh with teeth 24 formed on an engagement member 23 fixed to the drive shaft 17. Further, a gear 25 is fixed to the back side portion of the drive shaft 17, and a drive gear 26 rotatably supported by the back side plate 18 and the support plate 19 is engaged with the gear 25. When the drive gear 26 is rotationally driven by a motor (not shown), the rotation is transmitted to the drive shaft 17 via the gear 25, and the rotation of the drive shaft 17 is caused by the engagement member 23 and the rear flange 16. Is transmitted to the image carrier 2. As a result, the image carrier 2 is rotationally driven counterclockwise in FIG. 1, and the above-described image forming operation is executed.

  As shown in FIGS. 2 and 3, the unit main body 6 of the developing unit 3 has a front side plate 27 and a back side plate 28, and the shaft 5 of the developing roller 4 is supported by the side plates 27 and 28. It is rotatably supported through Further, a rotating body gear 29 is fixed to the back end portion of the shaft 5, and an idler shaft 30 is fixed to the back side plate 28 of the unit body 6 as shown in FIG. 3, and the idler gear 30 is connected to the idler shaft 30. 31 is rotatably supported, and its idler gear 31 meshes with the above-described rotating body gear 29. The idler shaft 30 may be rotatably supported by the unit body 6 and the idler gear 31 may be fixed to the idler shaft. In short, the idler gear 31 may be rotatably supported by the unit main body 6 via the idler shaft 30. It is also possible to provide a plurality of idler gears that mesh with each other.

  As described above, the rotating body unit configured as the developing unit 3 includes the rotating body gear 29 fixed to the shaft 5 of the developing roller 4, which is an example of the rotating body, and the idler shaft 30 with respect to the unit body 6. And at least one idler gear 31 that is rotatably supported.

  On the other hand, as shown in FIG. 2, a support shaft 32 is rotatably supported by a back plate 18 and a support plate 19 of the image forming apparatus main body 14 via a bearing, and a main body gear 33 is fixed to the support shaft 32. As shown in FIG. 3, the main body gear 33 is engaged with the idler gear 31. The support shaft 32 is rotationally driven by a motor (not shown). As described above, the rotating body gear 29 is drivingly connected to the main body gear 33 that is rotatably supported by the image forming apparatus main body 14 via the at least one idler gear 31.

  When the motor is operated and the main body gear 33 is driven to rotate, the rotation is transmitted to the shaft 5 of the developing roller 4 via the idler gear 31 and the rotating body gear 29, and the developing roller 4 is rotated clockwise in FIG. And the above-described developing operation is executed. FIG. 4 is a diagram for explaining the meshing state of the rotating body gear 29, the idler gear 31, and the main body gear 33, and the positions of these gears are slightly different from the actual ones.

  As shown in FIGS. 2 and 3, positioning members 34 and 35 are arranged outside the respective longitudinal ends of the unit body 6, and the positioning members 34 and 35 allow the image carrier 2 and the development to be performed. The shafts 5 of the rollers 4 are positioned and connected to each other. That is, annular projections 36 and 37 concentric with the drive shaft 17 are provided on the flanges 15 and 16 fixed to the respective end portions of the image carrier 2, and the outer peripheral surfaces of the annular projections 36 and 37. In addition, holes 40 and 41 formed in the positioning members 34 and 35 are detachably fitted through the bearings 38 and 39, respectively. The shaft 5 of the developing roller 4 is also rotatably fitted to the positioning members 34 and 35 via bearings 51 and 52. Thereby, the image carrier 2 and the developing roller 4 are positioned. Further, a secondary reference hole 42 made of a long hole is formed in the positioning member 35 on the back side, and a secondary reference pin 43 fixed to the unit main body 6 is fitted in the secondary reference hole 42. Similarly, as shown in FIG. 2, a secondary reference hole 53 made of a long hole is also formed in the positioning member 34 on the near side, and a reference pin 43 is fitted in the secondary reference hole 53. Thus, the unit main body 6 is prohibited from rotating around the central axis of the developing roller 4 by fitting the sub reference pin 43 into the sub reference holes 42 and 53 formed in the positioning members 34 and 35. Is done.

  As described above, the image carrier 2 and the developing roller 4 are correctly positioned and connected to each other to form an integral process cartridge 1. In addition, the distance between the central axis of the image carrier 2 and the central axis of the developing roller 4 is correctly regulated. As a result, when the image carrier 2 and the developing roller 4 are arranged so as to face each other with a small gap as in the illustrated example, the gap is correctly maintained, and the image carrier 2 When the developing roller 4 is configured so as to be in contact with and opposed to each other, the contact pressure is correctly regulated, and in any case, a high-quality toner image is formed on the image carrier 2. Can do.

  Further, in the process cartridge 1 of this example, as shown in FIG. 2, screws 44 and 54 are inserted into the secondary reference holes 53 and 42 formed in the positioning members 34 and 35, respectively. Since 54 is formed on the secondary reference pin 43, it is screwed onto the screw and tightened, whereby the secondary reference pin 43 is fixed to the positioning members 35 and 36. In this way, the unit main body 6 and the positioning members 34 and 35 are fixedly connected to each other, thereby preventing the inclination of the idler shaft 30 due to the bending of the unit main body 6, and the idler gear 31 and the gears 29 and 33 meshing with the idler gear 31. The variation in the inter-axis distance can be prevented, the gear meshing unevenness can be suppressed, and the image quality of the toner image formed on the image carrier 2 can be improved.

  In addition, in the process cartridge 1 of this example, a common pin is used as the slave reference pin 43 fitted in the slave reference holes 53 and 42 formed in the front positioning member 34 and the rear positioning member 35, respectively. The secondary reference pin 43 extends substantially parallel to the shaft 5 of the developing roller 4. As described above, the front side portion and the back side portion of the secondary reference pin 43 are concentrically positioned, so that fluctuations in the inter-axis distance between the idler gear 31 and the main body gear 33 due to the inclination of the unit main body 6 are prevented. This also makes it possible to form a high-quality toner image on the image carrier 2.

  As described above, since the flanges 15 and 16 fixed to the image carrier 2 are fitted to the drive shaft 17 rotatably supported by the image forming apparatus main body 14, the image carrier 2 is connected to the image forming apparatus. It is correctly positioned with respect to the body 14. In addition, as shown in FIGS. 2 and 3, the positioning pin 45 projecting from the positioning member 35 on the back side is fitted into the positioning hole 55 formed on the back side plate 18 of the image forming apparatus main body 14, and the front side. The positioning pin 46 projecting from the positioning member 34 on the side fits into the positioning hole 56 formed in the face plate 22, thereby preventing the process cartridge 1 from rotating around the central axis of the image carrier 2. The entire process cartridge 1 is correctly positioned with respect to the image forming apparatus main body 14.

  To remove the process cartridge 1 from the image forming apparatus main body 14, the front door 50 shown in FIG. 2 is opened, the face plate 22 is detached from the front side plate 20, and then the process cartridge 1 is pulled out to the front side as indicated by an arrow B. That's fine. At this time, the drive shaft 17 remains in the image forming apparatus main body, and the idler gear 31 of the process cartridge 1 is disengaged from the main body gear 33 on the image forming apparatus main body side. Thus, the image carrier 2 and the development unit 3 can be separated by removing the positioning members 34 and 35 from the image carrier 2 and the development unit 3 after taking the process cartridge 1 out of the image forming apparatus main body. .

  The process cartridge 1 can be correctly positioned and loaded at a predetermined position in the main body of the image forming apparatus by an operation reverse to the operation described above. A guide groove (not shown) is formed in the process cartridge 1, and a guide rail (not shown) is also fixed to the image forming apparatus main body 14, and the process cartridge 1 is pulled out on the front side or on the back side. When pushed in, the guide groove fits into the guide rail and slides along the guide rail.

  By the way, when the process cartridge 1 is loaded into the image forming apparatus main body and the image forming operation is performed as described above, an external force is applied to the idler gear 31 by the rotating main body gear 33. 5, reference numeral 33P indicates a pitch circle of the main body gear 33, and similarly, reference numeral 31P indicates a pitch circle of the idler gear 31. When the main body gear 33 rotates, the pressure circle α deviates from the common tangent line T of these pitch circles. An external force F is applied from the main body gear 33 to the idler gear 31 in the direction of the acting line S. Therefore, with only the above-described configuration, the idler shaft 30 is periodically bent and deformed by the force F and vibrates, and the vibration is transmitted to the image carrier 2 and formed on the image carrier 2. Banding may occur in the toner image.

  Therefore, in the process cartridge 1 of this example, as shown in FIGS. 3 to 5, the free end side of the idler shaft 30 is fitted into the hole 47 formed in the positioning member 35 and supported by the positioning member. ing. Thus, the idler shaft 30 is held by the positioning member 35 so that the external force F transmitted from the main body gear 33 to the idler gear 31 is received by the positioning member 35 when the main body gear 33 rotates. The idler shaft 30 is received by the positioning member 35 so that the idler shaft 30 is not bent and deformed by the external force F. As a result, vibration of the idler shaft 30 is prevented or effectively suppressed due to the external force F exerted on the idler gear 31 from the main body gear 33, and banding is formed on the toner image formed on the image carrier 2. Occurrence can be prevented. Even when a plurality of idler gears engaged with each other are rotatably supported by the unit main body 10 via the respective idler shafts, the respective idler shafts are arranged so that the external force applied to the respective idler gears is received by the positioning member It is held by the positioning member. In this way, a high quality image can be obtained.

  In the process cartridge 1 of this example, as shown in FIG. 4, the idler shaft 30 has its base end fixed to the unit body 6, and the idler gear 31 rotates on the idler shaft 30 via a bearing. Supported as possible. At that time, the idler gear 31 is positioned in the axial direction by the positioning member 35 and the idler gear 31 is prohibited from moving in the axial direction. In the example shown in FIG. 4, a boss portion 48 is formed on the positioning member 35, the boss portion 48 and the flange portion 57 of the idler shaft 30 abut against the idler gear 31, and the gear 31 is free to move in the axial direction. Is prohibited. With this configuration, a dedicated member for positioning the idler gear 31 in the axial direction can be omitted, and the cost of the process cartridge 1 can be reduced.

  The process cartridge 1 having the image carrier 2 and the developing unit 3 has been described above. However, other process equipment, for example, the cleaning unit 9 shown in FIG. The process cartridge can also be configured to be a component of the cartridge 1.

  Further, in the illustrated process cartridge 1, the rotating body is composed of the developing roller 4, the rotating body unit is configured by the developing unit 3, and the developer D carried on the developing roller 4 is conveyed onto the image carrier 2. Although it is configured to form a toner image, the process cartridge can be configured in various other forms. For example, the rotator is constituted by the cleaning brush 11 shown in FIG. 1, the rotator unit is constituted by the cleaning unit 9, and the toner image formed on the image carrier 2 is transferred to a transfer material. The process cartridge can also be configured to remove the transfer residual toner adhering to the carrier 2 by the action of the cleaning brush 11.

It is a vertical sectional view showing an outline of a process cartridge and other process equipment. FIG. 2 is a partial cross-sectional plan view of the process cartridge shown in FIG. 1. It is a perspective view when a process cartridge is seen from the back side. It is explanatory drawing which shows the meshing state of a rotary body gear, an idler gear, and a main body gear. It is a figure explaining the force applied to an idler gear from a main body gear.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Process cartridge 2 Image carrier 3 Developing unit 4 Developing roller 5 Axis 6 Unit main body 9 Cleaning unit 11 Cleaning brush 14 Image forming apparatus main body 29 Rotating body gear 30 Idler shaft 31 Idler gear 33 Main body gear 34, 35 Positioning member 42 Reference hole 43 Secondary reference pin D Developer P Transfer material

Claims (7)

An image carrier, and a rotator unit, the rotator unit being disposed to face the image carrier, a unit main body that rotatably supports a shaft of the rotator, A rotating body gear fixed to the shaft of the rotating body, and at least one idler gear rotatably supported on the unit main body via an idler shaft, and the axes of the image carrier and the rotating body are: The rotating body gear is driven and connected to a main body gear rotatably supported by the main body of the image forming apparatus via the idler gear, and the rotation of the main body gear is coupled to the idler gear. A process cartridge that is transmitted to a shaft of a rotating body through a rotating body gear and is driven to rotate. The process cartridge is transmitted from the main body gear to the idler gear when the main body gear rotates. External force, to be received in said positioning member, a process cartridge wherein the idler shaft is held in the positioning member. The process according to claim 1, wherein the idler shaft is fixed to the unit body, and the idler gear is rotatably supported by the idler shaft and is positioned in the axial direction of the idler gear by the positioning member. cartridge. In order to prohibit the unit body from rotating around the central axis of the rotating body, a slave reference pin provided in the unit body is fitted in a slave reference hole formed in the positioning member, and the 3. The process cartridge according to claim 1, wherein the secondary reference pin is fixed to the positioning member. 4. The positioning member disposed on each outer side of each longitudinal end of the unit main body is connected by the secondary reference pin, and the secondary reference pin extends substantially parallel to the axis of the rotating body. Process cartridge. 5. The rotating body according to claim 1, wherein the rotating body is composed of a developing roller, and the rotating body unit is constituted by a developing unit, and a toner image is formed on the image bearing body by a developer carried on the developing roller. One of the process cartridges. The rotating body is composed of a cleaning brush, and the rotating body unit is constituted by a cleaning unit, and after the toner image formed on the image carrier is transferred to a transfer material, the transfer residual toner that adheres to the image carrier The process cartridge according to claim 1, wherein the process cartridge is removed by the action of the cleaning brush. An image forming apparatus comprising the process cartridge according to claim 1.

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