JP2012053150A - Drive transmission device, process cartridge, and image forming apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To simultaneously secure rotating accuracy of rotors from an image forming apparatus body to another imaging device such as a photoreceptor and a developing device and positional accuracy of the rotors; and to provide a drive transmission device, an image forming apparatus, and a process cartridge capable of suppressing the density irregularity thereby and providing a high-definition image.SOLUTION: The drive transmission device includes a plurality of rotation transmission systems using an involute spline joint for the drive transmission to driven rotors. The drive transmission device includes a joint drive transmission member 100 formed by integrating the involute spline joint with a reduction gear 11. At least one joint drive transmission member is formed in a superposed manner such that the reduction gear and the involute spline joint correspond with each other in the radial direction.

Description

  The present invention relates to a drive transmission device for an image forming apparatus such as a printer, a copier, a facsimile machine, or a multifunction machine thereof, an image forming apparatus provided with the drive transmission device, and a process cartridge used in the image forming apparatus.

  2. Description of the Related Art In recent years, with an image forming apparatus, as the image quality increases and the speed increases, image density unevenness tends to occur when rotational fluctuations occur in a rotating body included in a photosensitive member, a developing device, or a transfer device. For this reason, the rotational accuracy of these rotating bodies is required more severely. In particular, in the developing device, it is effective to separate the drive transmission system from the photosensitive member, which has a large rotational load and the rotational fluctuation most affects the image quality. On the other hand, it is also important for high image quality to accurately configure the gap (development gap) between the photosensitive member and the developing roller in the developing device. In addition, the image forming apparatus needs to be configured to be detachable from the apparatus main body from the viewpoint of life and easy replacement.

  As a rotational drive method that can simultaneously satisfy the requirements for the rotational accuracy of a plurality of rotating bodies and the positional accuracy between the rotating bodies, a joint is used to transmit the rotation from the drive system of the image forming apparatus main body to the rotating body in the image forming apparatus. A method to use has been proposed in the past.

  A means using an involute spline joint is known as a rotational drive transmission means for obtaining highly accurate rotation. FIG. 8 is a perspective view showing a schematic configuration showing a configuration of a rotational drive transmission device using an involute spline joint. A photoconductor 101 that is an image carrier is supported by a photoconductor shaft 102, and one end of the photoconductor 101 is a photoconductor side joint 103 that is rotated and transmitted. In the rotational drive transmission device having such a configuration, for example, an input from the photoconductor drive motor 106 such as a DC servo motor or a stepping motor is transmitted to the drive side joint 104 via the photoconductor drive shaft 105, and the drive side joint 104 is transmitted. And the photoconductor side joint 103 are engaged with each other, so that the photoconductor 101 rotates.

  Further, Patent Document 1 or Patent Document 2 describes a joint structure for independently transmitting driving to the photosensitive member and the developing device. In Patent Document 1, the drive transmission of the photosensitive member is constituted by a twisted triangular prism-shaped joint, and the drive transmission to another image forming apparatus is constituted by a two-claw joint. In Patent Document 2, the drive transmission of the photoconductor is configured by an involute spline joint, and the drive transmission to another image forming apparatus is configured by Oldham coupling.

  By the way, high-precision rotation is realized by using an involute spline joint for rotation driving to the photosensitive member or other image forming apparatus, but ensuring the positional accuracy between the rotating members is not considered. In the inventions described in Patent Document 1 and Patent Document 2, a drive transmission system to the photoconductor and another image forming apparatus is configured independently, and an involute spline joint or a triangular prism joint is used for the photoconductor. Although accurate rotation is realized, the other image forming apparatus uses a two-claw joint or Oldham joint, and rotation fluctuation may occur.

  For this reason, the thing which integrated the involute spline joint and the reduction gear was proposed for the purpose of suppressing generation | occurrence | production of density unevenness and improving the quality of an image (patent document 3).

  In the device described in Patent Document 3, it is possible to simultaneously ensure the rotational accuracy of the rotating bodies of other developing devices such as the photosensitive member and the developing device and the positional accuracy of the rotating members.

  However, it has a two-stage structure including a pulley and a gear unit, which are reduction gears, and a joint unit that applies a driving force to the photosensitive member and the developing device, and the space for the drive transmission device is increased. In addition, the photosensitive member and the developing roller are close to each other in configuration, and both the joint drive transmission members overlap each other, so that the space for the drive transmission device is further increased. Therefore, there is a problem that the image forming apparatus cannot be reduced in size.

  SUMMARY OF THE INVENTION The present invention has been made in view of such a state of the art, and the problem to be solved by the present invention is that the rotation accuracy of the rotating body of the image forming apparatus main body to the photosensitive member and the developing device of another imaging device such as a developing device. In addition, the positional accuracy between the rotating bodies is to be secured at the same time. Accordingly, there are provided a drive transmission device, an image forming apparatus, and a process cartridge capable of suppressing density unevenness and realizing a high-quality image.

  The drive transmission device of the present invention comprises a plurality of rotation transmission systems that use involute spline joints for drive transmission to a driven rotating body, and joint drive transmission in which a speed reducer and a female joint or male joint of an involute spline joint are integrated. A drive transmission device having members, wherein at least one joint drive transmission member is formed in a superposed manner so that the speed reduction device and the involute spline joint correspond to the radial direction.

  According to the drive transmission device of the present invention, since an involute spline joint is used, a highly accurate rotational driving force can be obtained. Moreover, the at least one joint drive transmission member is formed in a superposed manner so that the reduction gear and the involute spline joint correspond to the radial direction. Become.

  The speed reducer is selected from gears, toothed pulleys, or friction drive means. It is preferable that one joint drive transmission member is disposed at a portion overlapping with the speed reducer of the other joint drive transmission member.

  The image forming apparatus of the present invention includes the drive transmission device. The process cartridge of the present invention is used in the image forming apparatus.

  According to the drive transmission device of the present invention, a highly accurate rotational driving force can be obtained. In addition, since the involute spline joint and the speed reducer are a so-called single stage, space saving and size reduction can be achieved.

  As the speed reducer, various publicly known mechanisms such as gears and toothed pulleys can be used, and the structure can be simplified and the cost can be reduced.

  If the joint drive transmission member is disposed at a portion overlapping with the speed reducer of another joint drive transmission member, it is possible to further reduce the space and size.

  The image forming apparatus of the present invention can achieve high image quality, space saving, and downsizing. Further, the process cartridge of the present invention can be applied to an image forming apparatus capable of realizing high image quality, space saving, and miniaturization.

1 is a configuration diagram of an image forming apparatus using a drive transmission device of the present invention. It is a perspective view of the drive transmission device of the present invention. It is a principal part perspective view of the drive transmission apparatus shown in the said FIG. FIG. 3 is a perspective view showing one joint drive transmission member of the drive transmission apparatus shown in FIG. 2. It is sectional drawing of the joint drive transmission member shown in FIG. It is a perspective view which shows the other joint drive transmission member of a drive transmission apparatus. It is sectional drawing of the joint drive transmission member shown in FIG. It is a simplified perspective view of the conventional drive transmission device.

  DESCRIPTION OF EMBODIMENTS Hereinafter, embodiments for carrying out the present invention according to embodiments shown in the drawings will be described.

  FIG. 1 is a main configuration diagram of an image forming unit of a tandem type color image forming apparatus according to the present invention. In this image forming apparatus, photosensitive drums 110Y, 110C, 110M, and 110Bk are provided for four colors of yellow (Y), cyan (C), magenta (M), and black (Bk), respectively. A charging unit, developing rollers 111Y, 111C, 111M, and 111Bk, primary transfer rollers 131Y, 131C, 131M, and 131Bk, a cleaning unit, a charge eliminating unit, and the like along the outer periphery of each of the photosensitive drums 110Y, 110C, 110M, and 110Bk, respectively. Image forming elements are arranged. Further, an optical writing unit is set on the downstream side of the charging unit in the rotation direction of the photosensitive drum, and optical writing is performed from the laser exposure unit 120 using laser light for optical writing.

  The laser exposure unit 120, for example, shapes the laser light emitted from laser diodes (LD) provided for each color, and the axial direction (main scanning direction) of each of the photosensitive drums 110Y, 110C, 110M, and 110Bk by a polygon mirror. Are irradiated with laser beams LBY, LBC, LBM, and LBBk modulated in accordance with image information. In the example of the figure, process cartridges 160Y, 160C, 160M, and 160Bk are detachably provided for each color. The process cartridges 160Y, 160C, 160M, and 160Bk for the respective colors are the photosensitive drums 110Y, 110C, 110M, and 110Bk, and charging units and development units (not shown) arranged along the outer periphery of the photosensitive drums 110Y, 110C, 110M, and 110Bk. At least one of the rollers 111Y, 111C, 111M, and 111Bk, the cleaning unit, and the charge removal unit is included as a unit together with these drive mechanisms.

  The intermediate transfer belt 130 stretched between the driving roller 130a and the driven roller 130b is in contact with each of the photosensitive drums 110Y, 110C, 110M, and 110Bk. The toner images on the photosensitive drums 110Y, 110C, 110M, and 110Bk are transferred to the intermediate transfer belt 130 by the primary transfer rollers 131Y, 131C, 131M, and 131Bk. A secondary transfer roller 140 is provided at a position facing the driven roller 130 b of the intermediate transfer belt 130, and the transfer paper is conveyed through the nip between the intermediate transfer belt 130 and the secondary transfer roller 140. The toner image on the intermediate transfer belt 130 is transferred onto the transfer paper by the secondary transfer roller 140. A fixing device 150 for fixing the toner image on the transfer paper onto the transfer paper is provided downstream of the nip between the intermediate transfer belt 130 and the secondary transfer roller 140 in the transfer paper conveyance direction.

  In the image forming apparatus including the image forming unit, first, laser is irradiated from the laser exposure unit 120 to each of the photosensitive drums 110Y, 110C, 110M, and 110Bk, and the surface of each of the photosensitive drums 110Y, 110C, 110M, and 110Bk is statically applied. An electrostatic latent image is formed. Subsequently, the toner is conveyed to the photosensitive drums 110Y, 110C, 110M, and 110Bk by the developing rollers 111Y, 111C, 111M, and 111Bk adjacent to the photosensitive drums 110Y, 110C, 110M, and 110Bk, respectively, and a toner visible image is formed. The The visible images of the respective colors formed on the photosensitive drums 110Y, 110C, 110M, and 110Bk are transferred to the intermediate transfer belt 130 that contacts the photosensitive drums 110Y, 110C, 110M, and 110Bk in the order of Y, C, M, and Bk. Sequentially transferred. Further, the image is transferred onto the transfer paper conveyed at the same time by the secondary transfer roller 140 and melt-pressed by the fixing device 150 to form an image on the transfer paper. A full-color image can be obtained by forming four colors, but it is also possible to form a single-color image or a two-color image. (Hereinafter, Y, C, M, and Bk subscripts indicating colors are omitted when the photosensitive drums of the respective colors are described collectively)

  FIG. 2 is a perspective view showing an example of the drive transmission device according to the present embodiment. For example, a first rotating body drive system is constituted by a drive motor 1 composed of, for example, a DC servo motor or a stepping motor, a gear 2 that decelerates the drive force of the motor, a female joint 4, and a shaft support member 3 fixed to the apparatus body. The female joint 4 includes a cylindrical body 45 having an involute spline-shaped female joint portion 4a formed on the inner diameter surface thereof.

  The second rotating body drive system is composed of 5, 6, 7, and 8 deceleration trains and a female joint 9. Similar to the female joint 4, the female joint 9 includes a cylindrical body 50 having an involute spline-shaped female joint portion 9 a (see FIG. 3) formed on the inner diameter surface thereof. The joints 4 and 9 are pivotally supported by the same pivotal support member 3.

  Incidentally, as shown in FIGS. 4 and 5, a speed reducer 11 including a gear, a toothed pulley, and the like is formed on the outer diameter surface of the cylindrical body 50 constituting the female joint 9. The cylindrical body 50 includes a peripheral wall 51 and a bottom wall 52 that closes one opening of the peripheral wall 51, and a cylindrical central shaft 53 is disposed at the center of the peripheral wall 51. ing. This central shaft 53 is connected to the bottom wall 52.

  Thus, the Jonto driving force transmission member 100 having the female joint 9 and the speed reduction device 11 constitutes the speed reduction device 11 configured coaxially with the female joint 9 in a single stage. As a result, space saving can be realized, and the drive transmission device can be reduced in size, and in turn, the image forming apparatus using the drive transmission device can be reduced in size. The reduction gear 11 is a gear or a toothed pulley. Integrating them can reduce the number of parts and reduce costs, as well as suppressing the accumulation of dimensional tolerances due to multiple parts and eliminating assembly errors. Reduces rotation fluctuation and achieves high image quality.

  Further, the driven-side male joint 31 connected to the photoconductor 110 is fitted into the female joint 4. That is, the male joint 31 is composed of a cylindrical body or solid body in which an involute spline-shaped male joint portion 31a is formed on the outer diameter surface thereof. In this way, the drive-side female joint 4 and the driven-side male joint 31 are fitted to each other to form an involute spline joint in which rotational driving is smoothly transmitted.

  Further, the driven-side male joint 32 connected to the photoconductor 110 is fitted into the female joint 9. That is, the male joint 32 is formed of a cylindrical body or solid body in which an involute spline-shaped male joint portion 32a is formed on the outer diameter surface thereof. In this way, the drive-side female joint 4 and the driven-side male joint 31 are fitted to each other to form an involute spline joint in which rotational driving is smoothly transmitted.

By the way, when integrating the female joint 9 and the speed reducer 11, you may comprise as shown in FIG. 6 and FIG. In this case, the female joint 9 and the speed reducer 11 are arranged in a so-called two-stage along the axial direction.

  Integrating them can reduce the number of parts and reduce costs, as well as suppressing the accumulation of dimensional tolerances due to multiple parts and eliminating assembly errors. Rotational fluctuation can be suppressed and high image quality can be achieved. However, in the case shown in FIGS. 6 and 7, the female joint 9 and the speed reducer 11 are arranged in two stages along the axial direction, so that the space of the drive transmission device is increased. In addition, the photosensitive member and the developing roller are close to each other in configuration, and both the joint drive transmission members overlap each other, so that the space for the drive transmission device is further increased. Therefore, there is a problem that the image forming apparatus cannot be reduced in size.

  In the above embodiment, the driving side is the female joints 4 and 9, and the driven side is the male joints 31 and 32. However, the driving side may be a male joint and the driven side may be a female joint.

  Further, with respect to the involute spline, in order to improve the detachability in the thrust direction, as shown in FIG. 6, it is easy to guide each other by making the end 15a of the tooth 15 of the involute spline an acute angle or extending one tooth in the thrust direction. You may make it a shape.

  Further, when the joint is not fitted, the distance between the female joint 4 and the male joint 31 relating to the photosensitive system as the first rotation transmission system is set to the female joint 9 relating to the developing roller system as the second rotation transmission system. By constructing the distance smaller than the distance of the male joint 32, the involute joint of the photosensitive system is fitted first, and the developing system is guided along the photosensitive system, so that the image forming device can be more easily mounted on the apparatus body. It becomes possible to do. For example, when the female joint 4 and the male joint 31 relating to the photosensitive system are engaged with each other, it is desirable to set the distance until the female joint 9 and the male joint 32 relating to the developing roller system are engaged to about 2 mm to 5 mm.

  By driving the involute spline joint 3 with a configuration in which only a gear having a large diameter is passed from the motor 1, the component configuration can be simplified and transmission loss can be minimized. On the other hand, from the viewpoint of the actual motor specifications used in the image forming apparatus and the degree of freedom of component layout, a deceleration train using a motor and a toothed belt pulley may be configured as in the second rotating body drive system. Useful.

  In addition, this invention is not limited to the above-mentioned Example, Of course, a various change can be added in the range which does not deviate from the summary of this invention. Examples of the image forming apparatus according to the present invention include an electrophotographic copying machine, a laser beam printer, and a facsimile machine.

20 Involute spline joint 100 Joint drive transmission member 11 Reduction gear

JP 2000-276030 A JP 2000-75765 A JP 2009-69556 A

Claims (5)

A drive transmission device comprising a plurality of rotation transmission systems that use involute spline joints for drive transmission to a driven rotating body, and having a joint drive transmission member in which a reduction gear and a female joint or male joint of an involute spline joint are integrated. And
The drive transmission device, wherein the at least one joint drive transmission member is formed in an overlapping manner so that the speed reduction device and the involute spline joint correspond to the radial direction.   The drive transmission device according to claim 1, wherein the speed reduction device is selected from a gear, a toothed pulley, or a friction drive unit.   The dynamic transmission device according to claim 1, wherein one joint drive transmission member is disposed at a portion overlapping with a speed reduction device of another joint drive transmission member.   An image forming apparatus comprising the drive transmission device according to claim 1.   5. A process cartridge used in the image forming apparatus according to claim 4.

Images