JP2010096815A - Process cartridge, and image forming apparatus using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To make productivity excellent and to improve irregular rotation of a rotating body in an image forming apparatus and a process cartridge without causing upsizing of the image forming apparatus and the process cartridge. <P>SOLUTION: A portion of a coupling 11 of the process cartridge 10 is formed in the shape of a milling cutter 11B, which is symmetric with respect to an axial center of a drive shaft 12. When screwing a spring 13 and the coupling 11 on the drive shaft 12, the milling cutter 11B is gripped by a tool, thereby easily preventing rotation of the drive shaft 12 due to screw-tightening torque, and reliably screwing them. Since the milling cutter part 11B is close to a screw tightening position, the screw-tightening torque is not applied to the entire process cartridge 10, and does not cause twist. The milling cutter part 12A may be provided on the drive shaft 12 close to the screw tightening position. By providing a through-hole 11C at a portion of the coupling and inserting a pin in the through-hole 11C, rotation when tightening a screw is easily prevented. The through-hole 12B may be provided on the drive shaft 12 close to the screw tightening position. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a process cartridge mounted on an image forming apparatus using an electrophotographic process such as a copying machine, a printer, a facsimile machine, and a multifunction machine of these, and an image forming apparatus mounted with the process cartridge.

  The process cartridge disclosed in Patent Document 1 includes an external tooth coupling on its drive shaft, and this coupling is fixed by a drive shaft and a screw, and the internal teeth of the drive unit in the image forming apparatus main body. By fitting into the coupling, the axes are aligned with each other (see paragraph 0009 in the detailed description of the invention and FIG. 1 of the drawings). In the process cartridge disclosed in Patent Document 1, since a plurality of teeth are always meshed with each other at the time of rotation by using a coupling by meshing of external teeth and internal teeth, rapid speed fluctuations in one rotation cycle It is said that smooth rotation can be maintained. Further, it is disclosed that the coupling and the drive shaft can be stopped not only by screwing but also by D cut or oval shape. Patent Document 2 also discloses a similar coupling.

JP 2008-58360 A JP 2007-108349

  However, in order to position the process cartridge in the thrust direction with respect to the image forming apparatus or to enhance the feeling of setting the process cartridge, it is necessary to urge the process cartridge in the thrust direction by the urging member. For this reason, the urging member must be provided in the image forming apparatus main body or the process cartridge. As in the invention disclosed in the above patent document, when driving is transmitted from the apparatus main body using a coupling using external teeth and internal teeth, particularly when the coupling on the apparatus main body side and the drive gear are integrated, The image forming apparatus can be reduced in size when the urging member is provided in the process cartridge rather than in the image forming apparatus main body.

  In other words, the urging member is screwed to the drive shaft integrally with the coupling in the coupling of the process cartridge, so that the process cartridge is not enlarged by the urging member and the image forming apparatus can be reduced in size. It becomes.

  On the other hand, in the process cartridge production process, when the coupling and the urging member are screwed to the drive shaft, the screw or the rotating body integrated with the drive shaft, such as the photosensitive drum, is not gripped. It cannot be screwed because it is rotated by the tightening torque. When an external tooth coupling is provided, it is possible to prevent rotation during screw tightening by gripping the external tooth portion.

  However, the outer teeth of the coupling are usually finished with high accuracy in order to perform high-precision rotation, and the external teeth are scratched by gripping such a coupling, or in the worst case There is a risk of damage.

  In addition, the rotating body may be integrated with a peripheral device for the rotating body, for example, a gear for driving transmission to the cleaning brush. Even when this gear is gripped, the gear portion is similarly scratched or damaged. There is a risk of doing.

  Moreover, since the surface is damaged when the surface of the rotating body is gripped, the surface cannot be gripped. In general, since the gap between the cartridge frame and the rotating body of the process cartridge is very small, it is difficult to prevent rotation using these gaps. Even if this can be done, the efficiency of the work is poor. Further, if a portion that is not in the vicinity of the screw is gripped to prevent rotation, a tightening torque is applied to cause the entire process cartridge or the rotating body to be twisted.

  As described above, there is a problem that it is difficult to easily and reliably prevent the rotation at the time of screw fastening.

  The present invention has been made in view of the above problems, and provides a process cartridge and an image forming apparatus that have good productivity and good rotation unevenness of the rotating body without increasing the size of the image forming apparatus and process cartridge. The purpose is to do.

  The process cartridge according to the first aspect of the present invention includes an image carrier and at least one of a developing unit, a charging unit, a lubricant applying unit, and a cleaning unit, which are integrated into an image forming apparatus main body. In the detachable process cartridge, a coupling for transmitting a driving force from the image forming apparatus main body to an internal driving shaft, a biasing member for biasing in the thrust direction, and a rotation preventing means for the driving shaft. The coupling and the urging member are screwed to the drive shaft, and rotation prevention means for the drive shaft is provided in the vicinity of the screw for screwing.

  According to a second aspect of the present invention, in the process cartridge according to the first aspect, the rotation preventing means is provided in the coupling.

  According to a third aspect of the present invention, in the process cartridge of the first aspect, the rotation preventing means is provided on the drive shaft.

  According to a fourth aspect of the present invention, in the process cartridge according to any one of the first to third aspects, the rotation preventing means has a symmetrical shape with respect to the axis of the drive shaft.

  According to a fifth aspect of the present invention, in the process cartridge according to any one of the first to third aspects, the rotation preventing means is a through hole that passes through the drive shaft or the coupling, or both the drive shaft and the coupling. It is characterized by being.

  An image reading apparatus according to a sixth aspect is the process cartridge according to any one of the first to fourth aspects, wherein the rotation preventing means is provided on an outer periphery of the drive shaft or the coupling, or both of the drive shaft and the coupling. It is characterized by a certain milling surface.

  An image forming apparatus according to a seventh aspect is characterized in that the process cartridge according to any one of the first to sixth aspects is mounted.

  According to the present invention, by providing the rotation preventing means in the vicinity of the screw, rotation and twisting of the rotating body at the time of screw tightening can be prevented, and the screw fastening can be surely performed.

  Hereinafter, the best mode for carrying out the present invention will be described with reference to FIGS. However, these are merely embodiments and do not limit the scope of the claims of the present invention.

  FIG. 2 is a diagram showing a configuration of a color image forming apparatus as an example of an image forming apparatus that is an object of the present invention. This color image forming apparatus is an apparatus that forms one image from four color toners of yellow (hereinafter Y), cyan (hereinafter C), magenta (M), and black (K). The image forming apparatus also includes four photoconductors 1Y, 1C, 1M, and 1K as image carriers, which are driven to rotate in the direction A in FIG.

  FIG. 2 is a schematic cross-sectional view of one of the four process cartridges 10, and one of the four colors is shown because it has the same configuration. Each image forming unit develops a latent image formed on the surface of the photoconductor 1 with each color toner around each photoconductor 1 (φ30 mm), and develops a latent image formed on the surface of the photoconductor 1 with a toner image. A developing device 4, a lubricant applying device 3 for applying a lubricant to the surface of the photoreceptor 1, and a cleaning device 5 for cleaning the surface of the photoreceptor light 1 after the toner image transfer are arranged.

  Next, the process of obtaining a color image with this color image forming apparatus will be described. In FIG. 1, from the left in the drawing, toner is supplied to each color developing device 4 by a predetermined replenishment amount from a toner bottle 6 that replenishes toner filled with Y, C, M, and K toners by a transport path (not shown). . The transfer paper 24 is fed by a paper feed roller 25 and conveyed to the nip between the secondary transfer roller 23 and the intermediate transfer belt 21.

  The photosensitive drum 1 that has been uniformly charged in advance by the charging roller 2 is exposed and scanned with a laser beam by the writing unit 40, and an electrostatic latent image is formed on the photosensitive drum 1. Each electrostatic latent image is developed by the developing device 4 for each color, whereby toner images of Y, C, M, and K are formed on the surface of the photosensitive drum 1. Next, a voltage is applied to the transfer roller 20, and the toner on each photosensitive drum 1 is sequentially transferred onto the intermediate transfer belt 21.

  At this time, the image forming operation for each color is executed while shifting the timing from the upstream side toward the downstream side so that the toner image is transferred to the same position on the intermediate transfer belt 21. The image formed on the intermediate transfer belt 21 is conveyed to the position of the secondary transfer roller 23 and secondarily transferred to the transfer paper 24. The transfer paper 24 onto which the toner images of the respective colors have been transferred is conveyed to the fixing unit 30 and thermally fixed, and is discharged by a paper discharge roller 31. The residual toner on the photosensitive drum 1 is cleaned by the respective cleaning means 5, and the residual toner on the intermediate transfer belt 21 is cleaned by the transfer cleaning means 22, and these waste toners are waste toner in each cleaning unit. The paper is discharged from the process cartridge to a waste toner bottle (not shown) provided in the image forming apparatus by the transport screw.

The process cartridge 10 will be described with reference to FIGS.
FIG. 3A is an overview of the process cartridge 10. A coupling 11 for transmitting driving from the image forming apparatus main body 100 is provided behind the process cartridge 10. The outer periphery of the coupling 11 is a spur gear 11A. As shown in FIG. 3B, a stopper 16 on the protrusion is provided on the front side of the process cartridge 10, and this stopper 16 abuts against the opening 17 A of the rail 17 in the image forming apparatus main body 100. Thus, the thrust position of the process cartridge 10 with respect to the image forming apparatus is determined.

  FIG. 4 is a cross-sectional view around the drive shaft 12 at the rear of the process cartridge 10. A coupling 11 provided with external teeth 11A is screwed to a drive shaft 12 integrated with the photoreceptor 1 together with a spring 13 in the longitudinal direction of the shaft. The drive shaft 12 is supported by a bearing 15 press-fitted into the process cartridge frame.

  FIG. 5 shows a coupling 51 on the image forming apparatus main body 100 side, in which a fitting portion with the coupling 11 of the process cartridge 10 and a helical gear 51B for transmitting driving from the driving motor 50 are integrated. The inner periphery of the fitting portion is a spur gear 51A.

  FIG. 6 is a cross-sectional view around the drive shaft 12 behind the process cartridge 10 when the process cartridge 10 is mounted on the image forming apparatus main body 100. Drive is transmitted when the spur gear 11A on the outer periphery of the coupling 11 of the process cartridge 10 and the spur gear 51A on the inner periphery of the coupling 51 on the image forming apparatus main body 100 side are fitted. As a result, the plurality of teeth of the spur gear 11A and the spur gear 51A mesh with each other, so that rapid speed fluctuations in one rotation cycle can be eliminated and smooth rotation can be maintained. Further, the spring 13 of the process cartridge 10 is pushed by the protrusion 51C on the inner periphery of the coupling 51 on the image forming apparatus main body 100 side. As a result, the entire process cartridge 10 is urged forward.

  When the stopper 16 of the process cartridge 10 reaches the opening 17A of the rail 17 of the image forming apparatus main body 100 with the urging force as described above, the stopper 16 protrudes from the opening. The thrust position of the process cartridge 10 with respect to the image forming apparatus main body 100 is determined by one surface of the protruding stopper 16 abutting against the edge portion of the rail opening 17A. Thus, the spring 13 is not disposed on the image forming apparatus main body 100 side and is screwed to the inner periphery of the coupling 11 of the process cartridge 10, so that the coupling 11 and the process cartridge are not enlarged without enlarging the image forming apparatus main body 100. The entire 10 can be efficiently energized. Further, since the click feeling is generated when the urging force by the spring 13 and the stopper 16 jump out of the opening 17A, the sense of setting the process cartridge is high.

  FIG. 7A is an overview of the coupling 11. A part of the coupling 11 has a shape of a milling cutter 11 </ b> B and is symmetric with respect to the axis of the drive shaft 12. When the spring 13 and the coupling 11 are screwed to the drive shaft 12, the milling portion 11 </ b> B is gripped with a tool, so that the rotation of the drive shaft 12 due to the fastening torque can be easily prevented and the screw can be securely fastened. The process cartridge production efficiency is high. Further, since the screw fastening position is close to the milling portion 11B, the fastening torque is not applied to the entire process cartridge 10 and is not twisted. In particular, a small process cartridge using a small-diameter photosensitive drum (φ30 mm or less) is highly effective. As shown in FIG. 7B, a milling portion 12A may be provided on the drive shaft 12 close to the screw fastening position. Further, as shown in FIG. 7C, by providing a through hole 11C in a part of the coupling and inserting a pin into the through hole 11C, rotation at the time of screw fastening can be easily prevented. Further, as shown in FIG. 7D, a through hole 12B may be provided in the drive shaft 12 close to the screw fastening position.

  That is, by providing the rotation preventing means in the vicinity of the screw, the rotating body can be prevented from rotating and twisting at the time of screw tightening, and the screw fastening can be surely performed. And by providing the anti-rotation means in the coupling, the rotation and twisting of the rotating body at the time of screw tightening can be prevented, screw fastening can be easily and reliably performed, and the anti-rotation means is provided on the drive shaft. The rotation and twisting of the rotating body during screw tightening can be prevented, and the rotation prevention means has a symmetrical shape with respect to the axis of the drive shaft, preventing the rotation and twisting of the rotating body during screw tightening and screw tightening Can be performed more reliably. Further, by adopting a structure in which the rotation preventing means is a through hole penetrating the drive shaft or the coupling, or both, rotation and twisting of the rotating body at the time of screw tightening can be prevented, and screw fastening can be performed easily and more reliably. Even if the rotation preventing means is a milling surface on the outer periphery of the drive shaft or the coupling, or both, rotation and twisting of the rotating body at the time of screw tightening can be prevented, and screw fastening can be performed easily and more reliably.

FIG. 1 is a block diagram of a conventional color image forming apparatus according to an embodiment of the present invention. Schematic cross section of one of the four process cartridges Overview of process cartridge (A) and enlarged view (B) Sectional view around the drive shaft at the rear of the process cartridge Overview of coupling on the image forming apparatus main body Sectional view centering on the drive shaft behind the process cartridge when the process cartridge is installed in the image forming apparatus Overview of coupling (A) and sectional view (B), overview of modified example (C), sectional view of other modified example (D)

Explanation of symbols

1: Photoconductor 2: Charging device 3: Lubricant coating device 4: Developing device 5: Cleaning device 6: Toner bottle 10: Process cartridge 11: Coupling 11A: Spur gear (external teeth)
11B: Milling portion 11C: Through hole 12: Drive shaft 12A: Milling portion 12B: Through hole 13: Spring 14: Screw 15: Bearing 16: Stopper 17: Rail 17A: Rail opening 20: Transfer roller 21: Intermediate transfer belt 22 : Transfer cleaning means 23: secondary transfer roller 24: transfer paper 25: paper feed roller 30: fixing unit 31: paper discharge roller 40: writing unit 50: drive motor 51: drive gear coupling 51A: spur gear (internal tooth portion) )
51B: Hasuba gear 51C: Protrusion 100: Image forming apparatus main body

Claims (7)

In a process cartridge in which an image carrier and at least one of a developing unit, a charging unit, a lubricant applying unit, and a cleaning unit are integrally formed and detachable from an image forming apparatus main body,
A coupling for transmitting a driving force from the image forming apparatus main body to an internal driving shaft; a biasing member for biasing in the thrust direction; and a rotation preventing means for the driving shaft.
These coupling and biasing member are screwed to the drive shaft,
A process cartridge comprising rotation prevention means for the drive shaft in the vicinity of the screw for screwing. 2. The process cartridge according to claim 1, wherein the rotation preventing means is provided in the coupling. 2. The process cartridge according to claim 1, wherein the rotation preventing means is provided on the drive shaft. 4. The process cartridge according to claim 1, wherein the rotation preventing means has a symmetrical shape with respect to an axis of the drive shaft. 4. The process cartridge according to claim 1, wherein the rotation preventing means is a through-hole penetrating the drive shaft or the coupling, or both the drive shaft and the coupling. cartridge. 5. The process cartridge according to claim 1, wherein the rotation preventing means is a milling surface on an outer periphery of the drive shaft or the coupling, or both of the drive shaft and the coupling. Process cartridge. An image forming apparatus comprising the process cartridge according to claim 1.