JP5521760B2 - Image carrier driving apparatus and image forming apparatus - Google Patents

Description

  The present invention relates to an image carrier driving apparatus that rotates an image carrier and is provided in an image forming apparatus such as a copying machine, a facsimile machine, and a printer, and to such an image forming apparatus having the same.

  In an image forming apparatus such as a copying machine, a facsimile, or a printer, an image forming apparatus including an image carrier such as a latent image carrier such as a photosensitive member and an intermediate transfer member such as an intermediate transfer belt (for example, [Patent Document 1] to [Patent Document 1]-[ In Patent Document 8], image formation is performed by subjecting the image carrier to a charging process, an exposure process, a development process, a transfer process, and the like in accordance with the rotation of the image carrier.

  Therefore, in such an image forming apparatus, a drive source such as a motor for rotationally driving the image carrier is provided. However, when such image formation is performed, the rotational driving force from the drive source is subjected to rotational fluctuation. In other words, it is required to transmit to the image carrier with the speed fluctuation reduced as much as possible, that is, to rotate the image carrier stably with high accuracy. This is due to such fluctuations in rotation, and the uniformity and stability of the dot position accuracy that constitutes the output image is disturbed, resulting in jitter and density unevenness on the output image, and periodic density unevenness in the image. This is because image quality degradation called banding that causes a stripe pattern to appear on the image is caused, or color unevenness occurs when the image forming apparatus is a color machine and is expressed as a secondary color.

  On the other hand, since the rotational speed of such a drive source is generally larger than the rotational speed required for the rotation of the image carrier, a reduction gear using gears has been used in the past. However, the speed reduction device using gears has a problem in that the rotational movement of the image carrier occurs due to backlash when a rotational load is generated on the image carrier during the above-described steps. . Such a problem occurs not only in the speed reduction device but also in a rotation transmission mechanism including a gear, a timing belt, and the like. In addition, the rotation variation of the image carrier may be caused by the output variation of the drive source itself. This includes the case where a stepping motor is used as the drive source.

  In view of such circumstances, various techniques have been proposed in the past for stably and rotationally driving an image carrier with high accuracy. Such techniques include a structure in which an inertial body such as a flywheel is integrally provided on the rotation shaft of the image carrier (see, for example, [Patent Document 1] to [Patent Document 3]), an elastic body such as rubber, and a viscosity such as oil. The structure (for example, refer to [patent document 1], [patent document 2], [patent document 4] to [patent document 8]) in which the body is used for transmission of rotational driving force from a driving source has been proposed.

In the former configuration, the inertial force of the image carrier is increased by the inertial body, whereby a rotation transmission including a drive source such as a motor, a gear for transmitting the rotational drive force from the drive source to the image carrier, a timing belt, etc. The rotational fluctuation in the high frequency range generated by the mechanism is reduced, and the driving accuracy of the image carrier is improved. In addition, when the inertial body is provided, the natural vibration frequency of the rotation transmission mechanism is shifted to the low frequency side, for example, by about 10 Hz, compared to the case where the inertial body is not provided. Therefore, the high-frequency region that attenuates widens, and rotational fluctuation is reduced over a wider frequency band.
The latter configuration improves the driving accuracy of the image carrier by attenuating or absorbing the speed fluctuation of the image carrier by the elastic body and the viscous body.

Since the former configuration and the latter configuration have such characteristics, it is preferable that both be provided in order to improve the driving of the image carrier with high accuracy.
As such a configuration, conventionally, for example, a technique in which an inertial body is provided on an axis of rotation of an image carrier via an elastic body and rotates integrally (see, for example, [Patent Document 1]), this technique has been cited. According to the above, the dynamic damper effect is exhibited and the vibration is attenuated. As such a configuration, for example, a technique in which an inertial body is provided inside an image carrier and a rotating member that applies viscosity resistance using the viscosity of oil is brought into contact with the outer peripheral surface of the image carrier. (For example, refer to [Patent Document 2]). According to this technique, the speed variation of the image carrier is quickly attenuated.

However, the former technique has the following problems.
-Since the elastic body has a structure that holds the inertial body, there is a possibility that high viscosity may not be sufficiently applied due to the influence of vibration caused by the fall of the inertial body.
It is effective only in a region where the rotational fluctuation is relatively large, in other words, when the amplitude of the rotational fluctuation is relatively large.
・ After mounting the device, the viscosity applied by the elastic body cannot be adjusted according to the individual device differences.

The latter technique has the following problems.
The friction condition on the surface of the image bearing member varies greatly depending on the toner or the like adhering to the surface of the image bearing member, so that the speed variation attenuation of the image bearing member is not stable.

  The present invention includes an inertial body provided in an image forming apparatus such as a copying machine, a facsimile machine, and a printer, and a structure for attenuating fluctuations in the speed of the image carrier, and an image carrier that exhibits these functions satisfactorily. It is an object of the present invention to provide a driving device and such an image forming apparatus including the driving device.

In order to achieve the above object, the invention described in claim 1 includes a drive source for rotationally driving the image carrier, and a plurality of different diameters that rotate integrally with the image carrier and give inertia to the rotation of the image carrier. And an inertial body that engages the inertial body from the outside and imparts viscosity to the rotation of the inertial body, and the viscosity imparting means includes an elastic body integral with the inertial body, A rotating member that is a roller in contact with the elastic body in order to give viscosity to the rotation of the inertial body, and the elastic body is integrated with at least a portion having a maximum diameter among the plurality of portions. The image carrier driving device is provided.

According to a second aspect of the present invention, there is provided a drive source for rotationally driving the image carrier, an inertia member that rotates integrally with the image carrier and imparts inertia to the rotation of the image carrier, and externally relates to the inertia member. And a viscosity imparting means for imparting viscosity to the rotation of the inertial body, wherein the viscosity imparting means has a plurality of such properties that impart viscosity to the rotation of the inertial body at a position symmetrical to the rotation center of the inertial body. An image carrier driving apparatus comprising: a rotating member; and a support mechanism that varies the viscosity applied to the inertial body by supporting the plurality of rotating members so as to be displaceable .

  According to a third aspect of the present invention, in the image carrier driving device according to the second aspect of the present invention, the rotating member is an elastic roller having an elastic body at least in contact with the inertial body.

  According to a fourth aspect of the present invention, in the image carrier driving apparatus according to the third aspect, the inertia body has a plurality of portions having different diameters, and the elastic roller has a maximum diameter among the plurality of portions. It is characterized in that it is in contact with a portion that is not.

The invention according to claim 5, wherein, in the image bearing member driving device according to claim 2, wherein said viscosity imparting means has an elastic body integrally with the inertial body, the rotary member is in contact with the elastic member It is a roller.

  According to a sixth aspect of the present invention, in the image carrier driving apparatus according to the fifth aspect, the inertial body has a plurality of portions having different diameters, and the elastic body has at least a diameter of the plurality of portions. It is characterized by being integrated into a non-maximum part.

The invention of claim 7 is the image carrier driving device according to claim 1 ,
The viscosity imparting means includes a plurality of the rotating members so as to impart viscosity to the rotation of the inertial body at a target position with respect to the rotation center of the inertial body.

According to an eighth aspect of the present invention, in the image carrier driving device according to the seventh aspect, the viscosity imparting means includes a support member that supports the plurality of rotating members at fixed positions.

According to a ninth aspect of the present invention, in the image carrier driving device according to any one of the first to eighth aspects, the viscosity applying means includes the rotating member and the inertial body in contact with the rotating member or At least one of the inertial body and the elastic body integrated with the inertial body has a friction coefficient increasing portion subjected to processing for increasing the friction coefficient at a portion where they abut against each other.

The invention of claim 10, wherein, in the image bearing member driving device according to any one of claims 1 to 9, wherein the elastic body has at least a surface layer thereof is urethane rubber or silicone rubber having a predetermined hardness Characterized by being made of material

According to an eleventh aspect of the present invention, in the image carrier driving device according to any one of the first to tenth aspects, the viscosity imparting means includes a viscous resistance portion that imparts a viscous resistance to the rotation of the rotating member. It is characterized by.

According to a twelfth aspect of the present invention, in the image carrier driving device according to any one of the first to eleventh aspects, the image carrier driving device further includes a reduction mechanism for decelerating and transmitting the rotation of the driving source to the image carrier. The viscosity applying means is provided between the speed reduction mechanism and the image carrier.

According to a thirteenth aspect of the present invention, in the image carrier driving apparatus according to any one of the first to twelfth aspects, the image carrier driving device includes a speed reduction mechanism for decelerating and transmitting the rotation of the driving source to the image carrier. The viscosity imparting means is provided on the opposite side of the speed reduction mechanism with the image carrier interposed therebetween.

According to a fourteenth aspect of the present invention, there is provided an image forming apparatus comprising: the image carrier driving device according to any one of the first to thirteenth aspects; and an image carrier that is rotationally driven by the image carrier driving device. .

  The present invention provides a drive source for rotationally driving an image carrier, an inertia member that rotates integrally with the image carrier and gives inertia to the rotation of the image carrier, and engages the inertia member from the outside. Since the image bearing member driving device has a viscosity imparting means for imparting viscosity to the rotation of the body, the function of the inertial body and the function of the viscosity imparting means for attenuating the speed fluctuation of the image bearing member are satisfactorily exhibited. It is possible to provide an image carrier driving apparatus that can stably drive the carrier and contribute to good image formation.

  If the viscosity imparting means has a rotating member for imparting viscosity to the rotation of the inertial body, the function of the inertial body and the function of the viscosity imparting means for attenuating the speed fluctuation of the image carrier are rotated. It is possible to provide an image carrier driving apparatus that is satisfactorily exhibited by a relatively simple viscosity imparting means having a member, can stably drive the image carrier, and can contribute to good image formation.

  Assuming that at least a portion of the rotating member that is in contact with the inertial body is an elastic roller of an elastic body, the function of the inertial body and the function of the viscosity imparting means that attenuates the speed fluctuation of the image carrier are inertial. Provided is an image carrier driving apparatus that is satisfactorily exerted by a relatively simple viscosity imparting means having an elastic roller that comes into contact with the body, can stably drive the image carrier, and can contribute to good image formation. Can do.

  If the inertial body has a plurality of portions with different diameters, and the elastic roller is in contact with a portion of the plurality of portions with a diameter that is not maximum, the inertial body has such a shape as the inertial body. The function of the inertial body and the function of the viscosity imparting means for attenuating the speed fluctuation of the image bearing member while suppressing the increase in size and the size of the apparatus resulting from this are compared with the elastic roller that contacts the inertial body. Therefore, it is possible to provide an image carrier driving apparatus that can be satisfactorily exhibited by a simple viscosity imparting means, that can stably drive the image carrier and contribute to good image formation.

  If the viscosity imparting means has an elastic body integrated with the inertial body, and the rotating member is a roller in contact with the elastic body, the function of the inertial body and the speed fluctuation of the image carrier The function of the viscosity imparting means for attenuating the image is satisfactorily exhibited by a relatively simple viscosity imparting means having an elastic body integral with the inertial body and a roller in contact therewith, and the driving of the image carrier is stable, An image carrier driving apparatus capable of contributing to good image formation can be provided.

  If the inertial body has a plurality of portions having different diameters, and the elastic body is integrated with at least a portion of the plurality of portions having a diameter that is not the maximum, the inertial body has such a shape. While suppressing the increase in size of the inertial body and the size of the apparatus resulting from this, the function of the inertial body and the function of the viscosity imparting means for attenuating the speed fluctuation of the image carrier are the elastic body integrated with the inertial body and Provided is an image carrier driving apparatus that is satisfactorily exerted by a relatively simple viscosity imparting means having a roller that abuts on the roller and that can stably drive the image carrier and contribute to good image formation. be able to.

  If the viscosity imparting means includes a plurality of the rotating members so as to impart viscosity to the rotation of the inertial body at a position symmetrical to the rotation center of the inertial body, the function of the inertial body and the image bearing The function of the viscosity imparting means that attenuates the speed fluctuation of the body is to rotate by avoiding torque fluctuation and eccentricity due to the action of biased force due to the rotational members arranged symmetrically It is possible to provide an image carrier driving apparatus that is more satisfactorily exhibited by a relatively simple viscosity imparting means having a member, can stably drive the image carrier, and can contribute to good image formation.

  If the viscosity imparting means has a support mechanism in which the viscosity applied to the inertial body is variable by supporting the plurality of rotating members in a displaceable manner, the function of the inertial body and the speed variation of the image carrier The function of the viscosity imparting means that damps the vibration is optimal by the support mechanism to avoid torque fluctuations and eccentricity due to the action of the biased force due to the rotating member being arranged with symmetry. By making it possible to impart a high viscous resistance, it can be more satisfactorily exhibited by a relatively simple viscosity imparting means having a rotating member, and the drive of the image carrier can be stabilized, contributing to good image formation. A possible image carrier driving device can be provided.

  If the viscosity imparting means has a support member that supports the plurality of rotating members at fixed positions, the function of the inertial body and the function of the viscosity imparting means for attenuating the speed fluctuation of the image carrier are rotated. Relatively simple having a rotating member and a support member that supports the rotating member in place by avoiding torque fluctuations and eccentricity due to the action of biased force due to the symmetrical arrangement of the members Therefore, it is possible to provide an image carrier driving apparatus that is more satisfactorily exhibited than the above-described viscosity imparting means, can stably drive the image carrier, and can contribute to good image formation.

  The viscosity imparting means has a process of increasing a friction coefficient in at least one of the rotating member and the inertial body in contact with the rotating member or an elastic body integrated with the inertial body. If the friction coefficient increasing portion is provided, the friction coefficient increasing portion prevents or suppresses the slip of the rotating member, and functions as an inertial body and a viscosity imparting means that attenuates the speed fluctuation of the image carrier. However, it is possible to provide an image carrier driving apparatus that is more satisfactorily exhibited by a relatively simple viscosity imparting unit having a rotating member, that can stably drive the image carrier and contribute to good image formation. it can.

  If the elastic body is formed of a urethane rubber or silicon rubber material having a predetermined hardness at least on its surface layer, the elastic body prevents or suppresses the slip of the rotating member, and functions as an inertial body. And the function of the viscosity imparting means for attenuating fluctuations in the speed of the image carrier are better exhibited by a relatively simple viscosity imparting means having a rotating member, the drive of the image carrier is stable, and good image formation is achieved. It is possible to provide an image carrier driving apparatus capable of contributing to the above.

  If the viscosity imparting means has a viscous resistance portion that gives a viscous resistance to the rotation of the rotating member, it is possible to increase the viscous resistance by the viscous resistance portion and cope with a case where a large viscous resistance is required. The function of the inertial body and the function of the viscosity imparting means for attenuating the speed fluctuation of the image carrier are satisfactorily exhibited by the relatively simple viscosity imparting means having the rotating member, so that the image carrier can be driven. An image carrier driving apparatus that is stable and can contribute to good image formation can be provided.

  If there is a deceleration mechanism for decelerating and transmitting the rotation of the drive source to the image carrier, and the viscosity imparting means is provided between the deceleration mechanism and the image carrier, the drive source The function of the inertial body and the function of the viscosity imparting means for attenuating the speed fluctuation of the image carrier between the speed reduction mechanism and the image carrier downstream of the speed reduction mechanism in the transmission direction of the driving force toward the image carrier Therefore, it is possible to provide an image carrier driving apparatus capable of contributing to good image formation.

  If it has a speed reduction mechanism for decelerating the rotation of the drive source and transmitting it to the image carrier, and the viscosity imparting means is provided on the opposite side of the speed reduction mechanism across the image carrier, the drive In the direction of transmission of the driving force from the source to the image carrier, downstream of the speed reduction mechanism, on the opposite side of the speed reduction mechanism across the image carrier, the function of the inertial body and the viscosity that attenuates the speed fluctuation of the image carrier It is possible to provide an image carrier driving apparatus that exhibits the function of the applying unit satisfactorily, stabilizes the driving of the image carrier, and can contribute to good image formation.

  The present invention resides in an image forming apparatus having such an image carrier driving device and an image carrier that is rotationally driven by the image carrier driving device, so that the function of the inertial body and the speed fluctuation of the image carrier are attenuated. The function of the viscosity imparting means is exerted well, the driving of the image carrier is stable, the banding phenomenon of the image and the color unevenness phenomenon are prevented or suppressed, and the image with a uniform and stable dot position accuracy is excellent. An image forming apparatus capable of image formation can be provided.

1 is a schematic front view of an image forming apparatus to which the present invention is applied. FIG. 2 is a schematic diagram of an image carrier driving device provided in the image forming apparatus shown in FIG. 1. FIG. 3 is a schematic side view of the image carrier driving device shown in FIG. 2. FIG. 4 is a conceptual diagram showing that the driving of the image carrier is stabilized by the image carrier driving device shown in FIGS. 2 and 3. FIG. 4 is a correlation diagram showing that the driving of the image carrier is stabilized by the image carrier driving device shown in FIGS. FIG. 4 is a schematic front view of viscosity imparting means provided in the image carrier driving device shown in FIGS. 2 and 3. FIG. 7 is an enlarged front view of a part of the viscosity imparting means for explaining the action obtained by the viscosity imparting means shown in FIG. 6. FIG. 7 is a graph showing experimental results in which it has been confirmed that the driving of the image carrier is stabilized by the viscosity applying means shown in FIG. 6. FIG. 4 is a schematic view showing a part of a modification of the image carrier driving apparatus shown in FIGS. 2 and 3. FIG. 4 is a schematic view showing a part of another modification of the image carrier driving apparatus shown in FIGS. 2 and 3. FIG. 4 is a schematic view showing a part of still another modification of the image carrier driving apparatus shown in FIGS. 2 and 3. FIG. 5 is a schematic view showing a part of still another modification of the image carrier driving apparatus shown in FIGS. 2 and 3.

  FIG. 1 schematically shows an image forming apparatus to which the present invention is applied, which is a multicolor image forming apparatus capable of forming a color image. The image forming apparatus 100 is a combination machine of a color laser printer and a facsimile, but may be another type of image forming apparatus such as another type of printer, facsimile, copying machine, copying machine and printer combination machine, or the like. . The image forming apparatus 100 performs an image forming process based on an image signal corresponding to image information received from the outside. This is the same when the image forming apparatus 100 is used as a facsimile. The image forming apparatus 100 can form an image on a sheet-like recording medium using not only plain paper generally used for copying, but also OHP sheets, cardboard, cardboard, cardboard, and envelopes. It is.

  The image forming apparatus 100 is a cylindrical rotation that is a latent image carrier as a plurality of image carriers that can form images as images corresponding to colors separated into yellow, magenta, cyan, and black, respectively. This is a tandem structure that adopts a tandem structure in which the photosensitive drums 20Y, 20M, 20C, and 20BK as body are arranged in parallel, in other words, a tandem image forming apparatus.

  The photoconductor drums 20Y, 20M, 20C, and 20BK have the same diameter, and transfer belts as transfer transfer belts that are intermediate transfer members that are endless belts disposed almost in the center of the main body 99 of the image forming apparatus 100. 11 are arranged at equal intervals on the outer peripheral surface side, that is, on the image forming surface side.

  The photosensitive drums 20Y, 20M, 20C, and 20BK are arranged in this order from the upstream side in the A1 direction that is the moving direction of the transfer belt 11. The photoconductive drums 20Y, 20M, 20C, and 20BK are image stations 60Y, 60M, 60C, and 60BK that are image forming units as image forming units for forming yellow, magenta, cyan, and black images, respectively. Is provided.

  The visible image, that is, the toner image formed on each of the photosensitive drums 20Y, 20M, 20C, and 20BK is superimposed and transferred onto a transfer sheet that is a transfer medium that is a recording medium conveyed by the transfer belt 11 that moves in the arrow A1 direction. It has come to be.

  In the superimposing transfer on the transfer paper, the toner image formed on each of the photoconductive drums 20Y, 20M, 20C, and 20BK is transferred to the same position on the transfer paper while the transfer paper is moved in the A1 direction by the transfer belt 11. As described above, voltage application by transfer units 12Y, 12M, 12C, and 12BK as transfer chargers disposed at positions facing the respective photosensitive drums 20Y, 20M, 20C, and 20BK across the transfer belt 11 is performed. The timing is shifted from the upstream side toward the downstream side in the A1 direction, and the transfer is performed at the transfer position that is opposite to the respective photosensitive drums 20Y, 20M, 20C, and 20BK and the transfer belt 11.

  The transfer belt 11 is an elastic belt whose entire layer is formed using an elastic member such as a rubber agent. The transfer belt 11 may be a single-layer elastic belt, may be an elastic belt using a part of the elastic belt, or a conventionally used fluorine-based resin, polycarbonate resin, or polyimide resin. Or an inelastic belt may be used.

  The image forming apparatus 100 is a transfer conveyance device that includes four image stations 60Y, 60M, 60C, and 60BK, and is disposed to face the photosensitive drums 20Y, 20M, 20C, and 20BK, and includes a transfer belt 11. And a transfer belt unit 10 as a certain belt unit.

  The image forming apparatus 100 is also transported from the sheet feeding device 61, a sheet feeding device 61 on which transfer paper transported between the photosensitive drums 20 </ b> Y, 20 </ b> M, 20 </ b> C, 20 </ b> BK and the transfer belt 11 is stacked. The recording sheet is transferred to the transfer portion between the photosensitive drums 20Y, 20M, 20C, 20BK and the transfer belt 11 at a predetermined timing in accordance with the toner image formation timing by the image stations 60Y, 60M, 60C, 60BK. It has a registration roller pair 13 that is fed out and a sensor (not shown) that detects that the leading edge of the transfer paper has reached the registration roller pair 13.

  The image forming apparatus 100 also includes a fixing device 6 as a roller fixing type fixing unit for fixing the toner image onto the transfer paper onto which the toner image has been transferred, and the transfer paper that has passed through the fixing device 6 outside the main body 99. A paper discharge roller 7 for discharging, a paper discharge tray 17 disposed on the side of the main body 99 and for stacking transfer paper discharged to the outside of the main body 99 by the paper discharge roller 7, and yellow, magenta, And a toner bottle (not shown) as a toner hopper filled with cyan and black toners.

  As shown in FIG. 2, the image forming apparatus 100 also includes a CPU 75 and storage means such as a ROM and a RAM (not shown). The image forming apparatus 100 includes drive control of the photosensitive drums 20Y, 20M, 20C, and 20BK. And a display device (not shown) capable of displaying various states of the image forming apparatus 100 and various settings for the image forming apparatus 100 by an operator, that is, a user. And an operation panel 76 as input means that can perform the above.

  As shown in FIG. 1, the transfer belt unit 10 includes a transfer inlet roller 72 that also serves as a driving roller as a driving member as a plurality of winding members around which the transfer belt 11 is wound in addition to the transfer belt 11. And a driven roller 73.

  The transfer belt unit 10 is also disposed opposite to the transfer belt 11 and is disposed opposite to the transfer belt 11 on the downstream side of the charge eliminator 74 in the A1 direction. And a cleaning device 18 as a transfer belt cleaning device provided with a transfer cleaning brush (not shown) that cleans the transfer belt 11.

The transfer entrance roller 72 is rotationally driven by driving a motor as a drive source (not shown), and thereby the transfer belt 11 is rotationally driven in the A1 direction. The transfer entrance roller 72 is connected to a power source (not shown) and functions as a charging roller as a charging unit that charges the transfer belt 11 so that the transfer belt 11 electrostatically attracts the transfer paper.
The driven roller 73 functions as a tension roller that urges the transfer belt 11 so that the transfer belt 11 is rotationally driven with a constant tension.

  The static eliminator 73 neutralizes the charge on the surface of the transfer belt 11 charged by the transfer entrance roller 72 so that the pattern and other toners, paper dust, and the like on the transfer belt 11 are easily removed by the cleaning device 18.

The fixing device 6 includes a fixing roller 62 that is a heating roller having a heat source (not shown), and a pressure roller 63 that is pressed against the fixing roller 62, and adds a transfer sheet carrying a toner image to the fixing roller 62. By passing the toner image through a fixing portion that is a pressure contact portion with the pressure roller 63, the carried toner image is fixed on the surface of the transfer paper by the action of heat and pressure.
The sheet feeding device 61 includes a paper feed tray 15 that is a paper feed cassette on which transfer papers are stacked, and a paper feed roller 16 that feeds transfer papers stacked on the paper feed tray 15.

  Regarding the image stations 60Y, 60M, 60C, and 60BK, the configuration will be described as a representative of the configuration of the image station 60Y including the photosensitive drum 20Y. Since the configuration of the other image station is substantially the same, in the following description, for the sake of convenience, a reference numeral corresponding to the reference symbol assigned to the configuration of the image station 60Y is attached to the configuration of the other image station. Further, detailed description will be omitted as appropriate, and those with Y, M, C, and K at the end of the reference numerals are configurations for forming yellow, magenta, cyan, and black images, respectively. Will be shown.

  The image station 60Y including the photosensitive drum 20Y has a cleaning unit for cleaning the transfer device 12Y and the photosensitive drum 20Y around the photosensitive drum 20Y along a rotation direction B1 which is a clockwise direction in the drawing. A cleaning device 70Y, a charging device 30Y as a charging unit for charging the photosensitive drum 20Y to a high voltage, and a developing device 50Y as a developing unit for developing the photosensitive drum 20Y. doing.

  The image station 60Y is also disposed above the photosensitive drum 20Y and serves as an optical writing device that is a writing unit that exposes the photosensitive drum 20Y at a position between the charging device 30Y and the developing device 50Y in the direction B1. It has an optical scanning device 8Y as a writing device. The optical scanning device 8Y scans and exposes the surface to be scanned formed by the surface of the photosensitive drum 20Y to form an electrostatic latent image, which is a laser beam as a laser beam based on an image signal. LY is emitted.

  As shown in FIG. 2, the image station 60Y also includes a motor 81Y as a drive source for rotationally driving the photosensitive drum 20Y, and rotates as a drive unit that rotationally drives the photosensitive drum 20Y by the driving force of the motor 81Y. An image carrier driving device 80Y, which is a body driving device, is included. Details of the image carrier driving device 80Y will be described later.

  The image station 60Y constitutes a process cartridge as a photosensitive drum unit that is detachably attached to the main body 99, except for the transfer device 12Y, the optical scanning device 8Y, and the image carrier driving device 80Y. Yes. Making the process cartridge in this way and making it attachable to and detachable from the main body 99 has advantages in that replacement due to deterioration and the maintenance performance of the process cartridge itself and its surroundings are highly improved.

  With the configuration described above, the surface of the photosensitive drum 20Y is uniformly charged by the charging device 30Y as it rotates in the B1 direction, and corresponds to the yellow color by the exposure scanning of the beam LY from the optical scanning device 8. An electrostatic latent image is formed. The electrostatic latent image is formed by scanning the beam LY in the main scanning direction, which is a direction perpendicular to the paper surface, and performing sub scanning in the circumferential direction of the photosensitive drum 20Y by rotating the photosensitive drum 20Y in the B1 direction. This is done by scanning in the direction as well.

  To the electrostatic latent image formed in this manner, charged yellow toner supplied by the developing device 50Y adheres, and is developed into a yellow color to be visualized. The toner image, which is a visible image, is transferred to transfer paper that moves in the A1 direction by the transfer device 12Y, and foreign matters such as toner remaining after transfer are scraped off and stored by the cleaning device 70Y, and the photosensitive drum 20Y is charged. It is used for the next charging by the device 30Y.

  Similarly, toner images of the respective colors are formed on the other photosensitive drums 20C, 20M, and 20BK, and the formed toner images of the respective colors are the same on the transfer paper that moves in the A1 direction by the transfer units 12C, 12M, and 12BK. Sequentially transferred to the position.

  The transfer paper conveyed between the photosensitive drums 20Y, 20C, 20M, and 20BK and the transfer belt 11 is fed from the sheet feeding device 61, and is sensitized by the registration roller pair 13 based on the detection signal from the sensor. The toner image on the body drum 20 </ b> Y is sent out at a timing when the leading end of the toner image faces the transfer belt 11.

  When the toner images of all colors are sequentially transferred and carried on the transfer paper, the transfer paper peels off from the transfer belt 11 and enters the fixing device 6, and passes through the fixing portion between the fixing roller 62 and the pressure roller 63. The carried toner image is fixed by the action of heat and pressure, and a color image as a composite color image is formed on the transfer paper by this fixing process. The fixed transfer paper that has passed through the fixing device 6 passes through the paper discharge roller 7 and is stacked on the paper discharge tray 17. On the other hand, the transfer belt 11 that has finished transporting the transfer paper is discharged by the charge eliminator 74 and then cleaned by the cleaning device 18 to prepare for the transfer of the next transfer paper.

  As shown in FIG. 2, in the image forming apparatus 100, the image carrier driving devices 80Y, 80M, 80C, and 80BK have substantially the same configuration. Hereinafter, the image carrier driving devices 80Y, 80M, 80C, and 80BK will be described as the image carrier driving device 80. Accordingly, the photosensitive drums 20Y, 20M, 20C, and 20BK will be described as the photosensitive drum 20, and the motors 81Y, 81M, 81C, and 81BK will be described as the motor 81.

  As shown in FIG. 3, the image carrier driving device 80 includes a motor 81 and a speed reducing device 82 as a speed reducer for driving the photosensitive drum 20 by decelerating and transmitting the rotation of the motor 81 to the photosensitive drum 20. And a coupling 83 as a joint mechanism for connecting the speed reduction device 82 and the photosensitive drum 20.

  The image carrier driving device 80 is also provided on a driving shaft 81 a that functions as an output shaft of the motor 81 and serves as an input shaft to the speed reducing device 82, and is a first detecting means for detecting the rotational speed of the motor 81. And a second shaft for detecting the number of rotations of the photosensitive drum 20. The encoder 77 is connected to the drive shaft 82 a by a coupling 83. And an encoder 84 as detection means.

  The image carrier driving device 80 is also realized as a function of the control unit 40, and controls the rotational speed of the photosensitive drum 20 based on the rotational speed of the photosensitive drum 20 detected by the encoder 84. Means 41 are provided.

  The image carrier driving device 80 is also provided on a driving shaft 82a that functions as an output shaft of the speed reduction device 82 and serves as an input shaft to the coupling 83 and the photosensitive drum 20, and rotates together with the photosensitive drum 20. A disc-like flywheel 78 that is a disk-like member serving as an inertia member that gives inertia to the rotation of the photosensitive drum 20; and a viscosity imparting means 79 that engages the flywheel 78 from the outside and imparts viscosity to the rotation of the flywheel 78; have.

  The speed reduction device 82 uses a planetary gear speed reduction mechanism, and is arranged to reduce the rotational speed of the motor 81 to the rotational speed required for the rotation of the photosensitive drum 20 and transmit it to the photosensitive drum 20. Yes. Since the image carrier driving device 80 includes the speed reducing device 82, the image bearing member driving device 80 is a rotating body driving device that reduces the rotation from the motor 81 that is the driving source by the speed reducer and transmits the rotation to the photosensitive drum 20 that is the rotating body. Yes.

  In addition to the rotation control of the photosensitive drum 20 described above, the image carrier drive control unit 41 observes a speed fluctuation component from the outputs of the encoder 77 and the encoder 84, thereby changing the meshing frequency fluctuation of the planetary gear of the reduction gear 82, The fluctuations associated with the eccentricity of the drive shaft 82a, their higher order components, and the generation of the resonance frequency are observed, and the speed fluctuations amplified by superimposing them are observed. In this way, the image carrier drive control means 41 functions as rotation fluctuation information acquisition means for acquiring rotation fluctuation detection information from outputs of the encoder 77 and encoder 84, that is, detected rotation fluctuation. The image carrier drive control means 41 also functions as a viscosity control means for controlling the drive of the viscosity applying means 79 as will be described later.

  Here, the role and function of the flywheel 78 and the viscosity imparting means 79 will be described. The role and function is simply to keep the rotational speed of the photosensitive drum 20 constant for both the flywheel 78 and the viscosity imparting means 79. The flywheel 78 is used for the rotation of the photosensitive drum 20. The inertia and the uniform rotation speed of the photosensitive drum 20 perform this role and function, and the viscosity imparting means 79 gives viscosity to the rotation speed of the photosensitive drum 20 and is generated at the rotation speed. It plays this role and function by attenuating fluctuations.

  When the roles and functions of the flywheel 78 and the viscosity imparting means 79 are viewed from different angles, they act on the vibration system by the image carrier driving device 80 as follows. That is, as shown in FIG. 4, the application of inertia by the flywheel 78 is to move the resonance point to the low frequency band and to superimpose it on the resonance band so that the speed fluctuation is not amplified. Viscosity imparting by means of imparting a damping property to the vibration characteristics of the vibration type.

  Therefore, the flywheel 78 has a main role and function of preventing or suppressing fluctuations in the rotational speed of the photoconductor drum 20 and moving the resonance point to a low frequency band. It can be said that the main role and function are to attenuate or absorb the rotation speed fluctuation generated in the drum 20 and the vibration equivalent to this fluctuation. However, the former role and function are also exhibited by the viscosity imparting means 79, and the latter role and function are also exhibited by the flywheel 78. For example, as shown in FIG. 5, when the viscosity applied to the flywheel 78 by the viscosity applying means 79 is the rotational torque applied, the rotational torque applied is A as shown in FIG. ) When the rotational torque is applied 1.5 times as large as A, the rotational torque is applied as clearly shown by comparing the encircled portions in FIGS. In the case of FIG. 6B where the speed is large, the peak of the speed fluctuation rate is suppressed, and the speed fluctuation frequency band moves to the low frequency band. As described above, the image carrier driving device 80 is configured to realize high-accuracy rotational driving of the photosensitive drum 20 that is performed via the speed reduction device 82 that constitutes the drive transmission system of the photosensitive drum 20. In the drive transmission system, inertia and viscosity resistance are simultaneously applied.

  The flywheel 78 is a rotating disk that rotates together with the drive shaft 82a as the drive shaft 82a rotates, and is a rigid disk made of a rigid body. The rotational center of the flywheel 78 is processed so that the amount of eccentricity with respect to the rotational center of the drive shaft 82a and the rotational shaft 20a is reduced, and is provided so as to substantially coincide with them. Substantially coincides with the core. The flywheel 78 is directly attached to the drive shaft 82a so that the rotation surface thereof is perpendicular to the extending direction of the drive shaft 82a. When the drive shaft 82a rotates, flare vibration does not occur or viscous resistance is applied. It is reduced to the extent that it does not affect. The rotational radius of the flywheel 78, in other words, the disk diameter is determined together with the material and thickness that affect its specific gravity so as to obtain the required inertial force.

  As shown in FIG. 6, the viscosity imparting means 79 is a rotating member that abuts on the outer peripheral surface of the flywheel 78 and rotates in conjunction with the rotation of the flywheel 78. A pair of viscous resistance generating rollers 85 as viscous resistance applying rollers, and the viscous resistance generating rollers 85 are supported so as to be displaceable, and the pressure applied to the flywheel 78 is variable, whereby the viscosity applied to the flywheel 78 is variable. And a support mechanism 86 as a pressure setting mechanism.

  The viscous resistance generating roller 85 is an elastic roller made of low hardness urethane rubber. As long as the viscous resistance generating roller 85 is an elastic body, the viscous resistance generating roller 85 may be made of a silicon rubber material instead of a urethane rubber. The viscous resistance generating roller 85 does not have to be an elastic body as a whole, and it is sufficient that at least a portion in contact with the flywheel 78 is an elastic body, that is, at least the surface layer thereof may be an elastic body. The hardness of the elastic body portion constituting the viscous resistance generating roller 85 may be a predetermined hardness that provides an appropriate viscous resistance using the viscoelasticity generated by deformation when contacting the flywheel 78.

  Since the viscous resistance generating roller 85 is driven and rotated by the flywheel 78, at least one of the flywheel 78 and the viscous resistance generating roller 85 is provided with a viscous resistance generating roller 85 at a portion where they abut each other. It is preferable to provide a friction coefficient increasing portion that has been processed to increase the friction coefficient so as to be surely driven and rotated. In this embodiment, a friction coefficient increasing portion (not shown) is formed on the outer peripheral surface of the flywheel 78. The friction coefficient increasing portion is formed by a rubber coating process using a thin film.

  The support mechanism 86 includes a pair of pressure setting arms 87 made of a highly rigid material, which rotatably supports each viscous resistance generating roller 85 by supporting the shaft 85a of each viscous resistance generating roller 85 at one end thereof. The other end of each pressure setting arm 87 is rotatably supported, a rotation fulcrum 88 common to each pressure setting arm 87, a bracket 89 having the rotation fulcrum 88 fixed to the main body 99, and each pressure setting arm. A female screw 90 provided in the middle portion 87, a male screw 91 screwed into each female screw 90, and a motor 92 that rotationally drives the male screw 91 are provided.

  Each female screw 90 is threaded in directions opposite to each other. As shown in FIG. 6, each pressure setting arm 87 is rotated about the rotation fulcrum 88 by rotation of the male screw 91. Are moved close to or away from each other, that is, in a direction to open and close.

  As shown in FIG. 7, each pressure setting arm 87 causes each viscous resistance generating roller 85 to abut on the flywheel 78 at a position substantially symmetric with respect to the rotation center of the flywheel 78, that is, a substantially point-symmetrical position. I support it. Therefore, the viscous resistance generating rollers 85 sandwich the flywheel 78 with the same force by such opening and closing.

  As shown in FIG. 2, the motor 92 is controlled to be driven by the image carrier drive control means 41 realized as one function of the control means 40 and rotates the male screw 91. Accordingly, due to the elastic deformation and pressure deformation of each viscous resistance generating roller 85 by driving the motor 92, the viscous resistance to the flywheel 78 is the same symmetrically about the same rotational center at a position symmetrical to the rotational center of the flywheel 78. In addition to being generated with a force, that is, an equal load, this load, in other words, the applied pressure acts uniformly toward the shaft core and cancels out. Therefore, the drive shaft 82a is not deformed in the radial direction and rotates without being affected by fluctuation due to eccentricity. Since the friction coefficient increasing portion is formed at the time of rotation, the viscous resistance generating roller 85 is driven to rotate by the flywheel 78 without slipping, and is stably rotated, whereby the viscous resistance is stably generated. If such symmetry is obtained, the number of viscous resistance generating rollers 85 may be plural, and not limited to two as in the present embodiment, but may be three or more.

  The image carrier drive control means 41 drives the motor 92 to increase the pressure applied to the flywheel 78 by each viscous resistance generating roller 85 as shown in FIG. When 78 is tightened, the viscous resistance is increased, and when the pressure applied to the flywheel 78 by each viscous resistance generating roller 85 is decreased, the viscous resistance is decreased. As shown in FIG. 8, it was confirmed that when the viscosity resistance is applied by the viscosity applying means 79, the fluctuation of the rotational speed of the photosensitive drum 20 is suppressed. The image carrier drive control means 41 functions as a viscosity control means for controlling the viscosity resistance by controlling the drive of the viscosity applying means 79. The support mechanism 86 and the image carrier drive control unit 41 functioning as a viscosity control unit function as an applied viscosity adjusting unit that increases or decreases the viscosity applied to the flywheel 78 by the viscosity applying unit 79 based on the detected rotational fluctuation. .

  For this reason, the image carrier drive control means 41 functioning as the viscosity control means uses the rotation fluctuation detection information acquired by the image carrier drive control means 41 functioning as the rotation fluctuation information acquisition means, for example, the printing speed, in other words, the image forming speed. Even when the basic rotation speed of the motor 81 is changed due to the change, an optimum viscous resistance is given by feedback control corresponding to the change and the generation level of the rotation fluctuation occurring at the rotation speed. It is configured as follows. Accordingly, the image carrier drive control means 41 functioning as the viscosity control means is realized as a function of the storage means, and stores the viscosity resistance value that stores data relating to the relationship between the generation level of the rotation fluctuation and the viscous resistance force to be applied thereto. As shown in FIG. 2, the storage means, the motor controller 93 that drives the motor 92 under the control of the CPU 75 based on the data stored in the viscous resistance storage means, and the signal generated by the motor controller 93 to the motor 92. And a driver 94 for inputting. Therefore, regardless of the change in contact pressure over time of the developing device such as the developing device 50Y or the cleaning device such as the cleaning device 70Y, which is cited as a cause of the rotational fluctuation of the photosensitive drum 20, or the individual difference when the process cartridge is replaced, Viscous resistance is always optimized.

  The image carrier drive control means 41 functioning as the viscosity control means acquires the data in advance corresponding to the change in the basic rotation speed and stores it in the viscous resistance value storage means. If the rotation speed is changed, an optimum viscous resistance may be applied. In this case, the rotation fluctuation information acquisition unit is not necessary.

  The value of the viscous resistance force may be displayed on the display device of the operation panel 76, and the user may be able to change the value on the operation panel 76. In this way, for example, when the user recognizes banding and color unevenness by looking at the formed image, it is possible to adjust the image to a desired state while checking the image quality by manipulating such values manually. Become.

  By using the viscosity imparting means 79 having such a configuration, it is possible to impart a high viscous resistance to the flywheel 78 in combination with the fact that free vibration of the flywheel 78 does not substantially occur. Yes. Further, since various materials can be selected for the flywheel 78, the range of viscous resistance that can be imparted is extremely wide from ultra-soft to super-hard. It is possible to cope with. Further, the flywheel 78 is separate from the photoconductive drum 20, the fluctuation of the friction condition due to the adhesion of toner is prevented or suppressed, and the provision of the viscosity control means makes it possible to impart viscosity. In addition, the attenuation of fluctuations in the rotational speed of the photosensitive drum 20 is stabilized. Therefore, the rotation speed of the photosensitive drum 20 is stabilized, and the uniformity and stability of the dot position accuracy constituting the output image is ensured, thereby causing jitter and density unevenness on the output image, and the period in the image. Therefore, there is no deterioration in image quality called banding in which a stripe density pattern appears on the image due to a general density unevenness or color unevenness.

  As shown in FIG. 9, the image carrier driving device 80 is provided so that the flywheel 78 is adjacent to the large-diameter disk 78a, the small-diameter disk 78b, and the drive shaft 82a along the axial direction as a plurality of portions having different diameters. The viscous resistance generating roller 85 may be configured to abut on the small-diameter disk 78b having a small diameter among the large-diameter disk 78a and the small-diameter disk 78b. Thus, even if the viscous resistance generating roller 85 is brought into contact with the outer peripheral surface of the flywheel 78 while maintaining the inertia imparted by the flywheel 78, the total length of these diameters is reduced, and the image carrier is driven. The increase in size of the device 80 is suppressed. For this reason, the flywheel 78 becomes an extremely large disk due to the magnitude of inertia to be imparted by the flywheel 78, and it becomes difficult to accommodate the layout in the main body 99, and the rotational torque increases. The problem of ending up is solved or alleviated.

  The flywheel 78 shown in FIG. 9 has a two-stage shape with a large-diameter disk 78a and a small-diameter disk 78b. However, there may be three or more parts having different diameters, and the viscous resistance generating roller 85 If the diameter of the plurality of portions is in contact with the portion having the largest diameter, the increase in the size of the image carrier driving device 80 is suppressed while maintaining the inertia imparted by the flywheel 78. In terms of suppressing the increase in size of the image carrier driving device 80 in the total length direction of the diameter with the resistance generating roller 85, the viscous resistance generating roller 85 is a portion having the smallest diameter among the plurality of portions. It is desirable that they are in contact.

  In the configuration example shown in FIG. 9, the support mechanism 86 has a knob 95 as a configuration for driving the male screw 91 in place of the motor 92. In this configuration, the image carrier drive control means 41 does not function as a viscosity control means, and the viscosity applied to the flywheel 78 by the viscosity applying means 79 is increased or decreased by manually rotating the knob 95. Therefore, the support mechanism 86 functions as applied viscosity adjusting means.

  As shown in FIG. 10, in addition to the configuration shown in FIG. 9, a viscous resistance portion 96 as a viscous resistance generation mechanism that gives a viscous resistance to the rotation of the viscous resistance generation roller 85 may be provided. The viscous resistance portion 96 includes a holder portion 96a that is lightly press-fitted into the shaft 85a and fixed in a non-rotating manner, an oil 96b that is sealed inside the holder portion 96a, and a blade 96c that is a resistance-generating blade portion immersed in the oil 96b. And a joint 96d fitted to the viscous resistance generating roller 85 so that the blade 96c rotates on the same axis as the shaft 95a. Therefore, the viscous resistance portion 96 is interlocked with the rotation of the viscous resistance generating roller 85 and rotates the blade 96c in contact with the oil 96b against the viscosity of the oil 96b together with the viscous resistance generating roller 85, thereby causing the viscous resistance. The rotational resistance of the generating roller 85 is acquired, and a larger viscous resistance can be obtained by a combined action with the driven rotation of the flywheel 78 accompanied by elastic deformation of the viscous resistance generating roller 85. Also in this configuration, the viscous resistance is adjusted by selecting the material of the viscous resistance generating roller 85 so as to have an appropriate hardness.

  As shown in FIG. 11, the viscosity applying means 79 includes a support member 97 as a connecting arm that rotatably supports each viscous resistance generating roller 85 at a fixed position, instead of the support mechanism 86 described above. Also good. The support member 97 has a hole 97a as a plate escape hole so that the shaft 85a can be loosely fitted, and two fixing screw portions 97b for fixing to the main body 99 and preventing displacement. The support member 97 supports the shaft 85a of each viscous resistance generating roller 85 at a position symmetrical to the hole 97a so that each viscous resistance generating roller 85 contacts the flywheel 78 at the same position as the support mechanism 86. The distance between the shafts 85a is set so that the contact pressure of each viscous resistance generating roller 85 with respect to the flywheel 78 becomes an appropriate pressure. That is, an appropriate viscous resistance is determined from the amount of deformation of the viscous resistance generating roller 85 when the viscous resistance generating roller 85 contacts the flywheel 78 and the relationship between the magnitude of the viscous resistance obtained thereby, that is, the viscous resistance force. The distance between the axes 85a is set so that a force can be obtained.

  The support member 97 is made of a metal high rigidity material. This is avoided if the support member 97 has elasticity in supporting each viscous resistance generating roller 85 by the support member 97, because an action like a spring system vibration works and a complicated vibration mode is caused. It is to do. Therefore, in this configuration example, the viscous resistance is substantially generated only by the repulsive force due to the deformation of each viscous resistance generating roller 85. The support member 97 may be formed of plastic or the like instead of metal as long as it is a highly rigid material capable of obtaining such an action.

  In each configuration example described above, the viscosity applying unit 79 includes an elastic body in the viscous resistance generating roller 85 that is a rotating member for applying viscosity to the rotation of the flywheel 78. The elastic body is illustrated in FIG. As described above, the roller portion 98 may be provided as a viscous resistance imparting roller portion engaged with the flywheel 78 in a manner integrally provided on the outside of the flywheel 78, that is, on the outer peripheral surface. In this example, as the rotating member, a roller for contacting the outer peripheral surface of the roller portion 98 and rotating in conjunction with the rotation of the flywheel 78 and the roller portion 98, in other words, a roller for giving viscosity to the rotation by being driven. It has the rigid roller 42 which is.

  The roller unit 98 is formed by integrating a material that produces the same viscous resistance as the material of the above-described viscous resistance generating roller 85 on the outer periphery of the flywheel 78 by molding or the like. In this configuration example, the rigid roller 42 is driven and rotated by the roller portion 98 to generate viscous resistance. Therefore, at least one of the rigid roller 42 and the roller portion 98 is in contact with each other. In addition, it is preferable to provide a friction coefficient increasing portion that has been processed to increase the friction coefficient so that the rigid roller 42 is driven and rotated reliably. In this embodiment, a friction coefficient increasing portion (not shown) is provided on the outer peripheral surface of the rigid roller 42. It is formed by a coating.

  Such a configuration is also applicable to the configuration shown in FIG. 9 in which the flywheel 78 has a plurality of portions with different diameters. In other words, the roller portion 98 is integrated with at least a portion of which the diameter is not the largest so that the combined diameter of this portion and the roller portion 98 is smaller than the portion with the largest diameter. May be.

  In addition, such a configuration can also be applied to the configuration shown in FIG. 10, and the rigid roller 42 is not limited to two as long as symmetry is obtained in contact with the roller portion 98. Three or more may be provided, and the support thereof may be performed by the same configuration as the support mechanism 86 and the support member 97.

  The preferred embodiments of the present invention have been described above. However, the present invention is not limited to the specific embodiments, and the present invention described in the claims is not specifically limited by the above description. Various modifications and changes are possible within the scope of the above.

  For example, the image carrier driven by the image carrier driving apparatus according to the present invention is not limited to a latent image carrier such as a photoconductor, but may be an intermediate transfer member such as an intermediate transfer belt. The arrangement positions of the inertial body and the viscosity imparting means are not limited to the positions between the speed reduction mechanism and the image carrier as in the above-described configuration examples, and the image carrier is sandwiched as shown by the one-dot chain line in FIG. It may be on the opposite side of the speed reduction mechanism.

  The present invention can also be applied to an image forming apparatus of a so-called intermediate transfer system in which toner images of respective colors are sequentially transferred onto an intermediate transfer member and transferred to a recording medium in a lump. It is. The present invention can also be applied to a so-called one-drum type image forming apparatus that sequentially forms toner images of respective colors on a single photosensitive drum and sequentially superimposes the color toner images to obtain a color image. The present invention can also be applied to an image forming apparatus capable of monochrome image formation.

  The effects described in the embodiments of the present invention are only the most preferable effects resulting from the present invention, and the effects of the present invention are limited to those described in the embodiments of the present invention. is not.

20, 20Y, 20M, 20C, 20BK Image carrier 42 Rotating member, roller 78 Inertial body 78a, 78b Plural portions with different diameters 78b Non-maximum portions 79 Viscosity imparting means 80, 80Y, 80M, 80C, 80BK Image bearing Body drive device 81, 81Y, 81M, 81C, 81BK Drive source 82 Deceleration mechanism 85 Rotating member, elastic roller 86 Support mechanism 96 Viscous resistance portion 97 Support member 98 Elastic body 100 Image forming apparatus

JP 2005-80399 A Japanese Patent No. 3258393 JP-A-9-222826 JP-A-7-325445 Japanese Patent Laid-Open No. 10-240067 Japanese Patent No. 3347965 JP-A-2005-338307 Japanese Patent Laid-Open No. 10-171297

Claims (14)

A drive source for rotationally driving the image carrier;
An inertial body having a plurality of portions with different diameters that rotate integrally with the image carrier and give inertia to the rotation of the image carrier;
Viscosity imparting means for engaging the inertial body from outside and imparting viscosity to the rotation of the inertial body;
Have
The viscosity imparting means has an elastic body integral with the inertial body, and a rotating member that is a roller in contact with the elastic body in order to impart viscosity to the rotation of the inertial body,
The elastic body is integrated with at least a portion having a maximum diameter among the plurality of portions.
An image carrier driving device. A drive source for rotationally driving the image carrier;
An inertial body that rotates integrally with the image carrier and gives inertia to the rotation of the image carrier;
Viscosity imparting means for engaging the inertial body from the outside and imparting viscosity to the rotation of the inertial body;
Have
The viscosity applying means includes a plurality of rotating members that impart viscosity to the rotation of the inertial body at positions symmetrical to the rotation center of the inertial body, and the inertial body by supporting the plurality of rotating members displaceably. And a support mechanism that can vary the viscosity applied to the image bearing member. The image carrier driving device according to claim 2, wherein
An image carrier driving apparatus according to claim 1, wherein at least a portion of the rotating member that contacts the inertial body is an elastic roller of an elastic body. In the image carrier driving device according to claim 3,
The inertial body has a plurality of portions with different diameters,
The image bearing member driving device according to claim 1, wherein the elastic roller is in contact with a portion of the plurality of portions having a diameter not maximum. The image carrier driving device according to claim 2, wherein
The viscosity imparting means has an elastic body integrated with the inertial body,
The image carrier driving apparatus according to claim 1, wherein the rotating member is a roller in contact with the elastic body. In the image carrier driving device according to claim 5,
The inertial body has a plurality of portions with different diameters,
The image carrier driving apparatus according to claim 1, wherein the elastic body is integrated with at least a portion of the plurality of portions not having a maximum diameter. The image carrier driving apparatus according to claim 1 ,
The image bearing member driving apparatus according to claim 1, wherein the viscosity applying means includes a plurality of the rotating members so as to give viscosity to the rotation of the inertial body at a target position with respect to the rotation center of the inertial body. The image carrier driving device according to claim 7, wherein
The image bearing member driving apparatus, wherein the viscosity applying means includes a support member that supports the plurality of rotating members at fixed positions . The image carrier driving apparatus according to any one of claims 1 to 8 ,
The viscosity imparting means has a process of increasing a friction coefficient in at least one of the rotating member and the inertial body in contact with the rotating member or an elastic body integrated with the inertial body. An image carrier driving device having an applied friction coefficient raising portion . In the image carrier driving device according to any one of claims 1 to 9,
An image carrier driving apparatus according to claim 1, wherein at least a surface layer of the elastic body is formed of a urethane rubber or silicon rubber material having a predetermined hardness . In the image carrier driving device according to any one of claims 1 to 10 ,
The image bearing member driving device according to claim 1, wherein the viscosity applying unit includes a viscosity resistance unit that applies a viscosity resistance to the rotation of the rotating member . In the image carrier driving device according to any one of claims 1 to 11 ,
A deceleration mechanism for decelerating and transmitting the rotation of the drive source to the image carrier;
An image carrier driving apparatus , wherein the viscosity applying means is provided between the speed reduction mechanism and the image carrier . In the image carrier driving device according to any one of claims 1 to 12,
A deceleration mechanism for decelerating and transmitting the rotation of the drive source to the image carrier;
An image carrier driving apparatus characterized in that the viscosity applying means is provided on the opposite side of the speed reduction mechanism with the image carrier interposed therebetween . An image bearing member driving device according to any one of claims 1 to 13, an image forming apparatus having an image bearing member which is rotationally driven by the image bearing member driving device.

Images