JP2016188703A - Driving device and image forming device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a driving device capable of rotating and driving a driven body with high accuracy in the driving device transmitting rotary driving force from a driving source to the driven body through a planetary gear speed reduction device.SOLUTION: A copying machine 500 using a planetary gear mechanism of 2K-H type two-stage constitution as a planetary gear speed reduction device 30, decelerating the rotary driving force of a motor 20 from an output shaft 40 of the planetary gear speed reduction device 30 and transmitting the same to a drum shaft 50 of a photoreceptor drum 1, includes a following constitution. The drum shaft 50 supports the photoreceptor drum 1, and transmits the rotary driving force from the output shaft 40 to the photoreceptor drum 1. Further all of central axes of a first sun gear 30, an internal gear 32, a first carrier 34, a second sun gear 36, a second carrier 38, the output shaft 40, the drum shaft 50 and a drum 52 of the photoreceptor drum 1 are coaxially disposed, and the first carrier 34 is supported in a floated manner. A first side plate and a second side plate provided with holes supporting both ends of a carrier pin of each carrier, and a connecting portion connecting them are constituted by one component.SELECTED DRAWING: Figure 6

Description

  The present invention relates to a driving device that rotationally drives a driven body via a planetary gear reduction device, and an image forming apparatus including the driving device.

  In an image forming apparatus employing an electrophotographic method, an electrostatic latent image is formed on the surface of a rotating cylindrical image carrier (hereinafter referred to as a photosensitive drum), and toner is adhered to the formed electrostatic latent image. What is developed is widely spread. The developed toner image is primary-transferred to an endless belt (hereinafter referred to as an intermediate transfer belt) that is driven to rotate, and then fixed by performing secondary transfer on the recording paper, or directly transferred onto the recording paper, The image is obtained by fixing.

  And, the rotational drive force of the drive source is transmitted to the rotational drive of the photosensitive drum and the intermediate transfer belt through a planetary reduction device that can save space and achieve a high reduction ratio compared to a large-diameter resin gear. 2. Description of the Related Art Image forming apparatuses provided with a driving device that are widely used. Conventionally, various drive devices have been proposed as drive devices using planetary speed reducers. For example, Patent Document 1 describes a driving device (roller driving device) that rotationally drives a driven body (driving roller) such as a photosensitive drum or a driving roller of an intermediate transfer belt as follows. As shown in FIG. 13, the driving roller 80 is held by front and rear holders 81 and 82 via front and rear bearings, and the front holder 81 is held and positioned by the front plate 83 and the rear holder 82 is held by the rear plate 84. A planetary gear reduction device 85 (gear part) and a motor 86 as a drive source are arranged inside the drive roller 80, and the planetary gear reduction device 85 and the motor 86 are respectively held by the rear holder 82. The end opposite to the output of the motor 86 is supported on the rear plate via a bearing. With the configuration described above, the drive system is mounted in the drive roller 80, the drive device is saved in space, and the image forming apparatus is reduced in size.

  Patent Document 2 describes a photosensitive drum driving device having the following configuration. The planetary roller speed reduction mechanism and the motor are arranged outside the photosensitive drum, and the motor, the photosensitive drum, the output shaft of the planetary roller speed reduction mechanism, and the like are arranged on the same axis. By arranging them coaxially in this way, the space occupied in the radial direction of the photosensitive drum of the driving device is reduced, and the size of the image forming apparatus is reduced. Further, in the planetary roller speed reducing mechanism used in this photosensitive drum driving device, the planetary roller support shaft is supported only on one side by the roller holding member, and it is considered that the axial space is also reduced. .

  Patent Document 3 describes a driving device (actuator) including the following planetary gear reduction device (planetary gear mechanism). The sun gear (sun gear) in the second and subsequent stages is rotatably assembled to the first stage sun gear that extends to the opening on the output shaft side of the housing that holds the internal gear (ring gear). Further, the planetary gear (planetary gear), the planetary gear support shaft (planetary gear shaft), and the carrier (planetary carrier) are assembled in advance as a carrier assembly and incorporated into the housing. In this carrier assembly, a support shaft is passed through a needle bearing provided on a planetary gear (planetary gear), and both ends of the support shaft having a diameter smaller than that of the central portion are sandwiched between a first side plate and a second side plate. The first side plate is integrally provided with a plurality of legs. When the support shaft of the planetary gear is sandwiched between the second side plates, the first side plate and the second side plate are supported by the legs and the support. Connected by shaft. With this configuration, the assembling property of the planetary gear reduction device is improved, and the deformation of the carrier assembly is suppressed, and the durability of each gear is improved.

  However, the configuration described in Patent Document 1 has the following drawbacks. Both the motor 86 and the rear holder 82 are positioned by the rear side plate 84. Since the motor 86 is also held by the rear holder 82, the motor 86 is positioned by two parts. For this reason, depending on the variation in the dimensions of each part, an assembly failure may occur at the positioning portion of the motor 86 and the rear plate 84, or the motor 86 or the rear holder 82 may be assembled in a deformed state even if it can be assembled. is there. As a result, the following problems may occur due to poor assembly or deformation of the motor 86 or the rear holder 82. Positioning and holding of the planetary gear speed reduction device 85 and the motor 86 with respect to a driven body such as a photosensitive drum and an intermediate transfer belt, and positioning and holding of the driven body and the rear plate 84 cannot be performed with high accuracy, thereby deteriorating driving rotation quality. This is a problem that the drive body cannot be rotated with high precision.

  In the configuration described in Patent Document 2, as described above, the support shaft of the planetary roller is configured to be supported only on one side by the roller holding member. For this reason, the support shaft of the planetary roller is inclined, the planetary roller comes into contact with the sun roller or the fixed roller, and the durability of the planetary roller is reduced. This causes a problem that the rotation cannot be performed properly.

  Further, in the configuration described in Patent Document 3, as described above, the support shaft is passed through the needle bearing provided in the planetary gear, and both ends of the support shaft whose diameter is smaller than the central portion are connected to the first side plate of the carrier and the first side plate. It is sandwiched between two side plates. For this reason, the position of the hole for holding the support shaft of the planetary gear provided in the first side plate and the hole for holding the support shaft of the planetary gear provided in the second side plate due to variations in the dimensions of each part and assembly errors. There is a possibility that the planetary gear may be tilted. Due to this inclination, the durability of the planetary gear is lowered, or the rotation unevenness of one rotation of the planetary gear is generated, which causes a problem that high-precision rotation drive cannot be performed. In addition, there is no clearance between each carrier and each sun gear (sun gear) fitted to the input shaft so that a centering effect is provided, and rotation unevenness due to the gear accuracy of the planetary gear, sun gear, and fixed gear. Is transmitted to the output shaft side, which causes a problem that high-accuracy rotational driving cannot be performed.

  As described above, if high-precision rotation driving cannot be performed, speed fluctuations occur in the photosensitive drum and the intermediate transfer belt that should rotate at a constant speed with high precision, and jitter and density unevenness occur in the output image. When the speed fluctuation continues at a certain frequency, the periodic density unevenness occurs in the entire image, which is visually observed as a banded banding. The speed fluctuation of the photosensitive drum causes a sub-scanning position deviation of the exposure line of the writing system, and at the same time, a sub-scanning position deviation at the time of primary transfer to the intermediate transfer belt. Further, the speed fluctuation of the intermediate transfer belt causes a sub-scanning position shift between the primary transfer and the secondary transfer. Image quality is significantly degraded by banding due to this speed variation.

  The present invention has been made in view of the above-described problems, and an object of the present invention is to provide a highly accurate driving device in a driving device that transmits a rotational driving force from a driving source to a driven member via a planetary gear reduction device. It is providing the drive device which can be rotationally driven.

In order to achieve the above object, the invention according to claim 1 is a sun gear that rotates by receiving a rotational driving force from a driving source, an internal gear that is arranged coaxially with the sun gear, A plurality of planetary gears arranged at equal intervals in the circumferential direction in an internal gear and meshing with the sun gear and the internal gear, and the sun gear and the internal gear while rotatably supporting the planetary gear. At least two stages of planetary gear mechanisms having a carrier that is coaxially rotatable and a support shaft that is supported by the carrier and that rotatably supports the planetary gear, and the output carrier is provided on the final stage carrier. A planetary gear reduction device, a driven body that is rotationally driven by a rotational driving force decelerated by the planetary gear reduction device, and a rotational driving force that supports the driven body and that is output from the output shaft of the planetary gear reduction device To the driven body The driven gear shaft, the sun gear, the internal gear, the carrier, the output shaft, the driven shaft, and the central axis of the driven body are all on the same axis. And at least one carrier is float-supported with respect to the internal gear, and each carrier is fitted to both ends of a support shaft that rotatably supports the planetary gear, thereby supporting the support shaft. It consists of one part provided with a hole to hold.
In the present invention, the sun gear, the internal gear, the carrier, the output shaft of the planetary gear reduction device, the driven body shaft, and the central axis of the driven body are all arranged on the same axis, so that the drive source to the driven body The coaxiality can be minimized. Therefore, the positioning accuracy of the planetary speed reduction device and the drive motor with respect to the driven body and the positioning accuracy of the positioning and holding of the driven body and the main body device can be increased, and the driven body can be driven with high accuracy. Further, since one or more carriers are supported in a floating manner, even if the planetary gears and internal gears supported by the carriers have poor gear accuracy, the carriers are aligned according to the meshing, and the gears are arranged on the output shaft side. It is possible to suppress the rotation unevenness due to the gear accuracy. Further, the carrier is composed of one part, and by providing the holes that fit and hold the both ends of the support shaft that supports the planetary gear, the inclination of the support shaft that supports the planetary gear can be minimized. . That is, the positional accuracy of the positioning and holding of the support shaft of the planetary gear can be increased, and the occurrence of rotation unevenness due to one rotation of the planetary gear can be suppressed.

The present invention minimizes the coaxiality from the driving source to the driven body, can suppress the transmission of rotation unevenness to the output shaft side due to the gear accuracy of the planetary gear and the internal gear supported by the carrier that supports floating, and further, Occurrence of rotation unevenness of one rotation of the gear can also be suppressed.
Therefore, in the driving device that transmits the rotational driving force from the driving source to the driven body via the planetary gear speed reduction device, a driving device that can rotationally drive the driven body with high accuracy can be provided.

1 is an overall schematic diagram of a copier according to an embodiment. FIG. 3 is a perspective view of a main part of the photoreceptor driving device according to the first embodiment. FIG. 3 is a cross-sectional view of the photoreceptor driving device according to the first embodiment. The figure which shows the structure of a connection member. The figure which shows the other structure of a connection member. The assembly explanatory drawing of the planetary gear to the carrier comprised with one component. Explanatory drawing when assembling the planetary gear and the support shaft to the carrier. FIG. 6 is a cross-sectional view of a photoconductor driving device according to a second embodiment. FIG. 6 is a cross-sectional view of a photoreceptor driving device according to a third embodiment. Explanatory drawing of the deformation | transformation location in the seat surface of the internal gear which carries out the screw fastening to the drive side board. FIG. 6 is a cross-sectional view of a photoreceptor driving device according to a fourth embodiment. FIG. 6 is a cross-sectional view of a photoconductor driving device according to a fifth embodiment. The example of the drive device which rotationally drives the conventional to-be-driven body.

  Hereinafter, an embodiment in which the present invention is applied to an electrophotographic color copying machine (hereinafter referred to as a copying machine) that is an image forming apparatus will be described with reference to the drawings. First, an overall outline of the copier of the present embodiment common to the respective examples will be described. Here, FIG. 1 is an overall schematic diagram of the copying machine according to the present embodiment.

  The copier 500 in the present embodiment is a so-called tandem image forming apparatus, and employs a dry two-component developing system using a dry two-component developer. The copying machine 500 includes a copying machine main body 100, a paper feed table 200 on which the copying machine main body 100 is placed, a scanner 300 mounted on the copying machine main body 100, and an automatic document feeder 400 mounted on the scanner 300. Yes. The copier 500 receives image data that is image information read from the scanner 300 and performs image forming processing. As shown in the figure, the copying machine main body 100 includes a photosensitive member which is an image carrier as four driven bodies for each color of yellow (Y), magenta (M), cyan (C), and black (Bk). Body drums 1Y, 1M, 1C, and 1Bk are juxtaposed. These photosensitive drums 1Y, 1M, 1C, and 1Bk are arranged along the belt moving direction so as to contact the endless belt-shaped intermediate transfer belt 5 supported by a plurality of rotatable rollers including a driving roller. Has been placed.

  Further, around the photosensitive drums 1Y, 1M, 1C, and 1Bk, chargers 2Y, 2M, 2C, and 2Bk, developing devices 9Y, 9M, 9C, and 9Bk corresponding to the respective colors, and cleaning devices 4Y, 4M, 4C, and 4B, respectively. Electrophotographic process members such as 4Bk and static elimination lamps 3Y, 3M, 3C, and 3Bk are arranged in the order of processes. An optical writing device 17 is provided above each photosensitive drum 1. In addition, primary transfer rollers 6Y, 6M, 6C, and 6Bk, which are primary transfer units, are disposed at positions facing each other through the intermediate transfer belt 5 of each photosensitive drum 1.

  The intermediate transfer belt 5 is stretched around stretching rollers 11, 12, 13 and a tension roller 14, and is driven to rotate by the rotation of the stretching roller 12, which is a driving roller that is rotationally driven by a drive source (not shown). . Here, a belt cleaning device 19 is provided at a position facing the stretching roller 13 through the intermediate transfer belt 5, and removes residual toner remaining on the intermediate transfer belt 5 after the secondary transfer. The stretching roller 11 is a secondary transfer facing roller that faces the secondary transfer roller 7 that is a secondary transfer unit, and is interposed between the secondary transfer roller 7 and the secondary transfer roller 7 via the intermediate transfer belt 5. Forming part.

  On the downstream side of the secondary transfer nip portion in the transfer sheet conveyance direction, a transfer sheet conveyance belt 15 stretched around a tension roller pair 16 is provided, and the transfer sheet on which the toner image is secondarily transferred is fixed to the fixing device. Transport to 18. The fixing device 18 includes a fixing roller pair 8, and heat and pressure are applied at the fixing nip portion to fix the unfixed toner image on the transfer paper.

  Next, a copy operation of the multi-function device 500 in this embodiment will be described. When a full-color image is formed by the copying machine 500 according to the present embodiment, first, a document is set on the document table 401 of the automatic document feeder 400. Alternatively, the automatic document feeder 400 is opened, a document is set on the contact glass 301 of the scanner 300, and the automatic document feeder 400 is closed and pressed. Thereafter, when the user presses a start switch (not shown), when the document is set on the automatic document feeder 400, the document is conveyed onto the contact glass 301. Then, the scanner 300 is driven and the first traveling body 302 and the second traveling body 303 start traveling. Thereby, the light from the first traveling body 302 is reflected by the document on the contact glass 301, and the reflected light is reflected by the mirror of the second traveling body 303 and guided to the reading sensor 305 through the imaging lens 304. . In this way, the image information of the original is read.

  When the start switch is pressed by the user, a drive motor (not shown) is driven, and the stretching roller 12 as a drive roller is driven to rotate, so that the intermediate transfer belt 5 is driven to rotate. At the same time, the photoconductor drum 1Y is uniformly charged by the charger 2Y while being driven to rotate in the direction of the arrow in the drawing by the photoconductor drive device 10Y (not shown). Thereafter, a light beam Ly from the optical writing device 17 is irradiated to form a Y electrostatic latent image on the photosensitive drum 1Y. This Y electrostatic latent image is developed with Y toner in the developer by the developing device 9Y. During development, a predetermined developing bias is applied between the developing roller and the photosensitive drum 1Y, and the Y toner on the developing roller is electrostatically attracted to the Y electrostatic latent image portion on the photosensitive drum 1Y.

  The Y toner image developed and formed in this way is conveyed to a primary transfer position where the photosensitive drum 1Y and the intermediate transfer belt 5 come into contact with the rotation of the photosensitive drum 1Y. At the primary transfer position, a predetermined bias voltage is applied to the back surface of the intermediate transfer belt 5 by the primary transfer roller 6Y. The Y toner image on the photosensitive drum 1Y is drawn toward the intermediate transfer belt 5 by the primary transfer electric field generated by this bias application, and is primarily transferred onto the intermediate transfer belt 5. Thereafter, similarly, the M toner image, the C toner image, and the Bk toner image are also primarily transferred so as to sequentially overlap the Y toner image on the intermediate transfer belt 5. The transfer residual toner remaining on the intermediate transfer belt 5 after the secondary transfer is removed by the belt cleaning device 19.

  When the user presses the start switch, the paper feed roller 202 of the paper feed table 200 corresponding to the transfer paper selected by the user rotates, and the transfer paper is sent out from one of the paper feed cassettes 201. The fed transfer paper is separated into one sheet by the separation roller 203 and enters the paper feed path 204, and is transported to the paper feed path 101 in the MFP main body 100 by the transport roller 205. The transfer paper conveyed in this way is stopped when it strikes the registration roller 102. When using transfer paper that is not set in the paper feed cassette 201, the transfer paper set on the manual feed tray 105 is fed out by the paper feed roller 104 and separated into one sheet by the separation roller 108, and then the manual paper feed path. It is conveyed through 103. Then, it stops when it hits the registration roller 102.

  The toner images having the four colors superimposed on the intermediate transfer belt 5 are conveyed to a secondary transfer position facing the secondary transfer roller 7 as the intermediate transfer belt 5 rotates. Further, the registration roller 102 starts to rotate in accordance with the timing at which the composite toner image formed on the intermediate transfer belt 5 as described above is conveyed to the secondary transfer position. At this secondary transfer position, a predetermined bias voltage is applied to the back surface of the transfer paper by the secondary transfer roller 7, and due to the secondary transfer electric field generated by the bias application and the contact pressure at the secondary transfer position, The toner image on the intermediate transfer belt 5 is secondarily transferred onto the transfer paper at once. Thereafter, the transfer paper onto which the toner image has been secondarily transferred is conveyed to the fixing device 18 by the transfer paper conveying belt 15 and subjected to fixing processing by the fixing roller pair 8 provided in the fixing device 18. The transfer sheet on which the fixing process has been performed is discharged and stacked in a discharge tray 107 provided outside the apparatus by a discharge roller pair 106.

  Next, the structure for transmitting the rotational driving force from the driving source, which is a feature of the present invention, to the driven body such as the driving roller of the image carrier or the intermediate transfer belt via the planetary gear speed reduction device is described below. An example applied to the apparatus will be described with reference to the accompanying drawings. Here, the photosensitive drums 1Y, 1M, 1C, and 1Bk, which are driven bodies, are rotationally driven by the photosensitive member driving devices having the same configuration, and hence the symbols Y, M, C, and Bk corresponding to the respective colors are hereinafter referred to. The description is omitted. The present invention is also applicable to a roller driving device for the stretching roller 12 that is a driving roller for the intermediate transfer belt 5.

Example 1
First, Example 1 which is a first example of the present embodiment will be described with reference to the drawings. FIG. 2 is a perspective view of a main part of the photosensitive member driving device according to the present embodiment, FIG. 3 is a cross-sectional view of the photosensitive member driving device 10 according to the present embodiment, and FIG. FIG. 5 is a diagram illustrating another configuration of the connecting member. FIG. 6 is an explanatory view of assembling the planetary gear to the carrier constituted by one part. FIG. 7 is an explanatory view when the planetary gear and the support shaft are assembled to the carrier. (A) is a planetary gear supported via a conventional needle bearing, and (b) is a bearing of this embodiment. It is explanatory drawing about the planetary gear supported by a loess.

  As shown in FIG. 2, the photosensitive member driving device 10 mainly includes a motor 20 as a driving source, a planetary gear reduction device 30, a joint 41 as a connecting member, and a drum shaft 50 as a driven shaft. As shown in FIG. 3, the output shaft 40 of the planetary gear reduction device 30 is connected and fixed by a drum shaft 50 and a joint 41. A bearing 51 is press-fitted into the drum shaft 50, and is supported and positioned by the rear side plate 62 fixed to the casing of the apparatus main body via the bearing 51, and the front side plate 61 fixed to the apparatus casing. The front end vicinity of the drum shaft 50 is supported and positioned on the bearing 56 provided in the above. That is, the drum shaft 50 is positioned and supported at both ends by the front plate 61 and the rear plate 62, which are part of the housing of the image forming apparatus, via the bearings 51 and 56, respectively. And is positioned and supported with respect to the main body. As a result, the relative position of the photosensitive drum 1 is determined via a member (for example, the secondary transfer belt 5) that requires relative positional accuracy and the front side plate 61 and the rear side plate 62. The positional relationship with a plurality of members related to 1 can be determined with high accuracy.

  Next, details of the internal structure of the planetary gear reduction device 30 will be described with reference to FIG. The planetary gear reduction device 30 of the present embodiment uses a 2K-H type two-stage planetary gear mechanism. Here, although the planetary gear mechanism has a two-stage configuration in this embodiment, it is possible to further overlap the number of stages with three stages and four stages according to the reduction ratio. Further, the planetary gear reduction device 30 has a configuration in which all of the center shafts of the output shafts provided on the sun gear, the internal gear, the carrier, and the carrier of the final stage are arranged on the same axis.

  In this planetary gear reduction device 30, the first sun gear 31 is directly geared to the motor output shaft 21 of the motor 20 that is a drive source. Then, the first stage first planetary gear 33 meshing with the first sun gear 31 and the internal gear 32 fixed to the internal gear fixing flange 22 is supported by the first carrier 34 of the first stage, and the first sun gear 31 is engaged. The outer periphery of the gear 31 is revolved. The first planetary gear 33 is concentrically disposed at three locations on the first carrier 34 for rotational balance and torque sharing. As described above, in the present embodiment, the first planetary gears 33 are arranged at the positions of the first carrier 34 divided into three equal parts in the circumferential direction. Each first planetary gear 33 is configured to rotate while being supported by a first carrier pin 35 that is a support shaft that is fixedly supported at both ends by the first carrier 34. The first planetary gear 33 rotates and revolves due to the engagement of the first sun gear 31 and the internal gear 32, and the first carrier 34 that supports the first planetary gear 33 is the first sun gear 31. The first reduction ratio is obtained by decelerating to the rotation of.

  In the present embodiment, the first carrier 34 has no rotation support portion and is configured to perform floating rotation. And the 2nd sun gear 36 provided in the rotation center of the 1st career 34 serves as an input of the 2nd stage reduction gear mechanism. Details of the configuration of the first carrier 34, the first carrier pin 35, and the first planetary gear 33 will be described later.

  A second stage second sun gear 36 is supported by a second stage second carrier 38 with a second stage second planetary gear 37 meshing with the internal gear 32 integrally formed up to the second stage. Thus, the outer periphery of the second sun gear 36 in the second stage is revolved. In the present embodiment, the second planetary gears 37 are arranged at the positions of the second carrier 38 divided into four equal parts in the circumferential direction. Each second planetary gear rotates and revolves while being supported by a second carrier pin 39 supported at both ends by the second carrier 38. An output shaft 40 is provided at the center of rotation of the second carrier 38 in the second stage corresponding to the final stage, and is connected to the drum shaft 50 via a joint 41 on a hollow cylinder. Here, the output shaft 40 of the second carrier 38 is supported by a bearing press-fitted into an internal gear cap 42 positioned by the internal gear 32. Since the internal gear cap 42 is positioned by the inner circumference of the internal gear 32 and the inlay, the output shaft 40 has a coaxial degree with the central axis of the internal gear 32 even when it is driven to rotate. The configuration can be minimized. Further, the second carrier 38 at the final stage provided with the output shaft 40 does not move with respect to the internal gear 32, so that the rotation of the output shaft 40 does not change due to alignment during rotational driving, and the drum The coaxiality between the shaft 50 and the output shaft 40 can be minimized. Therefore, the photosensitive drum 1 as a driven body can be driven with high accuracy.

  In addition, the drum shaft 50 is provided between the photosensitive drum 1 and the output shaft 40, and the drum shaft 50 and the output shaft 40 are connected by a joint 41 so as to be coaxial. Here, as for the configuration of the joint 41, for example, the configurations as shown in FIGS. The joint 41 shown in FIG. 4 has a hollow cylindrical shape, and the drum shaft 50 and the output shaft 40 of the planetary gear reduction device 30 have the same diameter, and the joint 41 is press-fitted into the drum shaft 50 on the drum shaft 50 side. It becomes the composition which is done. Further, on the output shaft 40 side, the output shaft 40 has a clearance fit and is connected and fixed by a joint 41 and a stepped screw 43a. On the other hand, the joint 41 shown in FIG. 5 has a slit 41a at the center of a hollow cylindrical shape, and the output shaft 40 is connected and fixed by frictional force with the joint pushed and bent by the screw 43b. Yes. In either configuration, the shift between the central axis of the drum shaft 50 and the output shaft 40 due to the joint portion is minimized, and the drive can be transmitted.

  By providing the joint 41 in this manner, the photosensitive drum 1 and the drum shaft 50 can be attached and detached during maintenance and the like, and the drum shaft 50 supported and positioned by the front side plate 61 and the rear side plate 62 which are part of the main body housing. Thus, the photosensitive drum 1 can be positioned with high accuracy on the main body. Further, by making the joint 41 have a hollow cylindrical shape, the drum shaft 50 and the output shaft 40 can be fitted and connected to each other inside the cylinder. Thereby, the factor given to the coaxiality of the planetary gear speed reducer output shaft and the driven body shaft can be only the straightness inside the cylindrical member, and the coaxiality can be minimized.

  The motor output shaft 21 of the motor 20 is supported by an internal tooth fixing flange 22 as shown in FIG. The internal gear 32 is fixed to the internal gear fixing flange 22 with a screw 43, and the internal gear fixing flange 22 fixes and holds the internal gear 32 and the motor 20. The internal tooth fixing flange 22 is fixed to the driving side plate 63 with screws. Here, the driving side plate 63 is supported and positioned by a stud 64 that is crimped to the rear side plate 62. A hollow cylindrical boss is provided on the central axis of the internal gear 32 on the motor 20 side of the internal gear 32, and the motor 20 has a bearing provided on the cylindrical inner periphery and the motor 20 side. Positioned by fitting with inlay. The outer periphery of the hollow cylindrical shape is positioned by fitting with a hole formed in the internal tooth fixing flange 22 and an inlay.

  With this configuration, the central axis of the motor output shaft 21, the internal gear fixing flange 22, and the output shaft 40 of the planetary gear reduction device 30 are all coaxially arranged with reference to the internal gear 32, and the parts The coaxiality due to dimensional variation can be minimized. As a result, all the central axes from the motor output shaft 21 to the drum shaft 50 can be coaxially arranged, and the coaxiality due to variations in component dimensions can be minimized. Further, the planetary gear speed reduction device 30 is supported by the rear side plate 62 and the driving side plate 63 supported by the rear side plate 62, so that the planetary gear speed reduction device 30 and the planetary gear speed reduction device 30 itself are deflected by their own weight. Can be suppressed. Therefore, the coaxiality between the motor 20 and the drum shaft 50 can be minimized, and the photosensitive drum 1 can be driven with high accuracy.

  The photosensitive drum 1 includes a cylindrical drum 52 and drum flanges 53a and 53b. The drum 52 is positioned on the drum shaft 50 via drum flanges 53a and 53b provided at both ends of the drum. ing. The drum flanges 53a and 53b are provided with a hole at the center axis position of the drum 52, and the hole and the drum shaft 50 are positioned by an inlay. The drum shaft 50 is press-fitted with a joint 55 that transmits drive to the drum 52, and the drum 52 is driven via a drum flange 53a. With this configuration, in addition to the motor output shaft 21 to the drum shaft 50 described above, the central axis of the drum 52 can also be arranged coaxially. That is, the motor output shaft 21 (first sun gear 31), the internal gear 32, the first carrier 34 (second sun gear 36), the second carrier 38, the output shaft 40 of the planetary gear reduction device 30, the drum shaft 50, All the central axes of the drums 52 can be arranged on the same axis. By arranging in this way, it is possible to minimize the degree of coaxiality due to variations in the dimensions of each part.

  In this planetary gear reduction device 30, each component is made of the following materials. The first sun gear 31 directly cut by the motor output shaft 21 of the motor 20, that is, the input shaft of the planetary gear mechanism, the first carrier pin 35, and the second carrier pin 39 are made of a metal material such as stainless steel or carbon steel. It is composed. In addition, the other first planetary gear 33, the first carrier 34, and the integrated second sun gear 36, the second planetary gear 37, the second carrier 38, and the common gear that meshes with the first planetary gear and the second planetary gear. The internal gear 32 configured integrally with the housing case according to the specifications is formed of a molded material such as a resin material, such as polyacetal.

  As described above, since the material of at least the first planetary gear 33, the second planetary gear 37, and the internal gear 32 is resin, the resin is less rigid than the metal. Impact can be mitigated. Since it can be mitigated in this way, the rotational fluctuation due to the meshing of each gear can be reduced. Further, since the internal gear 32 is weak in rigidity, the internal gear 32 itself fluctuates in accordance with the accuracy of each gear when meshing with each planetary gear, resulting in a centering effect, and rotational fluctuation due to meshing. Can be minimized.

Next, a general description of the 2K-H type planetary gear mechanism will be given. The 2K-H type planetary gear mechanism is composed of four components: a sun gear, a planetary gear, a planetary carrier that supports the revolving motion of the planetary gear, and an outer gear. It is composed of Of the three elements of sun gear rotation, planetary gear revolution (carrier rotation), and outer ring gear rotation, one is fixed, one is input, and one is connected to the output. Depending on which one is assigned to input / output / fixed, multiple reduction ratios and rotation directions can be switched with one unit. The target 2K-H type two-stage structure in this embodiment is classified into compound planetary gear mechanisms (two or more 2K-H types), and each of the three basics of two or more 2K-H types. The two basic shafts of the shafts are connected to each other, one of the remaining basic shafts is fixed, and the other one shaft is used as a drive shaft or a driven shaft.
The reduction ratio is expressed by the following equation when the number of teeth of the sun gear is Za, the number of teeth of the planetary gear is Zb, and the number of teeth of the internal gear is Zc. The subscripts 1 and 2 in the formula mean the first and second stages.
Reduction ratio = Za1 / (Za1 + Zc1) × Za2 / (Za2 + Zc2)

  Next, the first carrier 34 in the first stage is configured in which each carrier of the present embodiment is configured by one part provided with holes for holding the carrier pins by fitting with both ends of the carrier pins. An example of the configuration will be described with reference to FIG. As shown in FIG. 6, the first carrier 34 is composed of a single component, and includes a first side plate provided with the second sun gear 36 and a second side plate on the motor 20 side, and three pieces connecting them. It consists of a connecting part. The first side plate and the second side plate are provided with holes 34a and 34b that support both ends of the first carrier pin 35, respectively. The first carrier 34 is configured such that the first planetary gear 33 and the first carrier pin 35 are assembled in advance and assembled to the planetary gear reduction device 30. When assembling the first planetary gear 33, the first planetary gear 33 is inserted from an opening provided with no connection portion on the side surface of the first carrier. The first carrier pin 35 is assembled by being inserted into the holes 34 a and 34 b of the first side plate and the second side plate of the first carrier 34. The diameter of the first carrier pin 35 is slightly larger than the holes 34a and 34b of the first carrier and is configured to be press-fitted. As described above, since both ends of the first carrier pin 35 are held by the first side plate and the second side plate of the first carrier 34 which are the same parts, in this embodiment, the inclination of the first planetary gear 33 is reduced. It is possible to do.

  Here, for example, as in the carrier of Patent Document 4, the first side plate and the second side plate provided separately are configured to sandwich and hold both end portions of the carrier pin that supports the planetary gear via the needle bearing. The following inconveniences may occur if they are simply integrated. As shown in FIG. 7A, when assembling the carrier pin 35 and the planetary gear 33 that support the planetary gear 33 via the two needle bearings 33a provided at both ends of the planetary gear 33 in the carrier 34, It will be assembled as follows. The planetary gear 33 is inserted from an opening that is not provided with a connecting portion on the side surface of the carrier 34. Then, the carrier pin 35 is inserted in order from the hole 34b side while fitting with the two needle bearings 33a provided on the planetary gear 33 and all the holes 34a and 34b provided on the first side plate and the second side plate of the carrier 34. And assemble. Assembling in this way, the assembling workability deteriorates. In particular, when the planetary gear 33 is provided with a needle bearing 33a, the fitting width with the carrier pin 35 is shortened, the carrier pin 35 is easily tilted during insertion, and it is difficult to fit into the hole on the downstream side in the insertion direction. Workability deteriorates. For this reason, conventionally, there have been many configurations in which the first side plate and the second side plate of the carrier are provided separately and assembled so as to sandwich both ends of the carrier pin that supports the planetary gear via the needle bearing.

  Therefore, in the present embodiment, as shown in FIG. 7A, a bearing in which the needle bearing 33a or the like is not provided at the sliding portion between the planetary gear 33 and the carrier pin 35 that rotatably supports the planetary gear 33 is provided. The structure is less. By making the sliding portion bearingless in this manner, the fitting width between the planetary gear 33 and the carrier pin 35 becomes long, so that the planetary gear shaft is not easily tilted when the carrier pin 35 is inserted. Therefore, the assembly workability when the carrier pin 35 and the planetary gear 33 are assembled in the carrier 34 is improved.

  Then, the present invention is applied to the photosensitive member driving device 10 that rotationally drives the photosensitive drum 1 as in this embodiment, that is, the driven member is the photosensitive drum 1 that is an image carrier. The following effects can be achieved. The photosensitive drum 1 as an image carrier can be driven with high accuracy at low cost and at a low cost, and the occurrence of image defects such as jitter related to rotational fluctuations of the photosensitive drum 1 can be suppressed. Further, as described above, the present invention can also be applied to a roller driving device for the stretching roller 12, which is a driving roller for the intermediate transfer belt 5, and the like. By applying to the roller driving device of the intermediate transfer belt 5, that is, by using the stretched roller 12 as the driving roller of the intermediate transfer belt 5 as the driven body, the following effects can be obtained. The intermediate transfer belt 5, which is an intermediate transfer belt, can be driven with high accuracy at low cost and at a low cost, and the occurrence of image defects such as color misregistration related to rotational fluctuations of the intermediate transfer belt 5 can be suppressed. Furthermore, by applying the present invention to the rotational driving device of the photosensitive drum 1 which is an important driven body for forming an image and the stretching roller 12 which is a driving roller of the intermediate transfer belt 5, high accuracy can be obtained. Can be rotated. Therefore, it is possible to provide an image forming apparatus capable of suppressing the occurrence of the image defect as described above, compared to applying to one of them.

(Example 2)
Example 2 which is a second example of the present embodiment will be described with reference to the drawings. FIG. 8 is a cross-sectional view of the photoreceptor driving device according to the present embodiment. Here, the same components as those in the first embodiment are denoted by the same reference numerals, and similar configurations and operations will be omitted as appropriate.
As shown in FIG. 8, in the photoreceptor driving device 10 of this embodiment, the output shaft 40 of the planetary gear speed reduction device 30 extends to the front side plate 61, and the drum 52 is output via drum flanges 53a and 53b. It is configured to be positioned by the shaft 40. Thus, since the output shaft 40 is configured to also serve as the drum shaft 50, it is possible to eliminate the buildup of coaxiality due to a connecting member such as the joint 41 that connects the output shaft 40 and the drum shaft 50. It has become. In this way, the joint 41 that is a connecting member is eliminated, and the output shaft 40 also serves as the drum shaft 50, that is, the output shaft 40 and the drum shaft 50 are configured integrally, so that the output shaft 40 and the drum shaft 50 are integrated. Coaxiality can be minimized.

Example 3
Example 3 which is a third example of the present embodiment will be described with reference to the drawings. FIG. 9 is a cross-sectional view of the photoconductor driving device 10 according to the present embodiment, and FIG. Here, the same components as those in the first embodiment are denoted by the same reference numerals, and similar configurations and operations will be omitted as appropriate.
The planetary gear reduction device 70 of the present embodiment uses a 2K-H type two-stage planetary gear mechanism as in the first embodiment. The motor 20, the first stage sun gear 31, the first stage planetary gear 33, the first carrier 34, the second sun gear 36, the second planetary gear 37, the first carrier pin 35, the second carrier pin 39, etc. are the first embodiment. It is the same composition as.

  As shown in FIG. 9, in the planetary gear reduction device 70 of the present embodiment, a female spline joint 73 is integrally formed with the second carrier 72 at the rotation center of the second carrier 72. On the other hand, a male spline joint 74 is press-fitted at the tip of the drum shaft 50, and is configured to be jointly connected to the planetary gear reduction device 70. Here, in this embodiment, the drum shaft 50 side is male and the second carrier side is female, but the reverse configuration may be used. By configuring the connecting portion in this way, the spline joint has a concentric effect at the time of rotational driving, so that the coaxiality between the spline joint 73 that functions as the output shaft of the planetary gear reduction device 70 at the time of rotational driving and the drum shaft 50 is minimized. Can be Further, the second carrier 72 is not provided with a rotation support portion with respect to the internal gear 71 and is configured to float. Thus, the second carrier 72 is aligned according to the meshing accuracy of the internal gear 71 and the planetary gear 37 during driving, and is configured to reduce rotation unevenness as the final output.

  Further, since the joints with the drum shaft 50 are spline joints 73 and 74, even if the spline joint 73 on the second carrier 72 side is aligned, the spline joint 74 is concentric accordingly. . For this reason, the rotation unevenness caused by the eccentricity caused by the alignment on the second carrier 72 side does not reach the drum shaft 51. Furthermore, since the material of the internal gear 71 is resin, it has also been confirmed that the internal gear 71 has an alignment effect.

  Here, the planetary gear speed reduction device 70 is configured to be fixedly held by screwing a seating surface 71a formed on the output side of the internal gear 71 and the driving side plate 65. The driving side plate 65 is positioned and supported by a stud 64 that is crimped to the rear side plate 62. If the stud 64 is not perpendicular to the rear plate 62 (perpendicularity in terms of geometrical tolerance in the drawing), the drive side plate 65 positioned and fixed via the stud is fixed with a certain inclination with respect to the rear plate. At this time, if the planetary gear reduction device 70 is also fixed in the same posture as the inclination of the driving side plate 65, the drum shaft 50 is positioned by the front side plate 61 and the rear side plate 62, and the following problems occur. there is a possibility. The spline joint 74 has an inclination with respect to the spline joint 73, and it is a problem that even if the spline joint 74 cannot be engaged well or can be engaged, rotation unevenness due to this shift occurs.

  However, in the configuration of the present embodiment, the seat surface 71a of the internal gear 71 and the drive side plate 65 are fixed, and the material of the internal gear 71 is resin, and the rigidity is weak against metal. Therefore, only the root portion of the seating surface 71a is deformed when the screw is fastened. As shown in FIG. 10, the seat surface 71 a follows the drive side plate 65, but the spline joint 73 can mesh with the spline joint 74 while maintaining the same axis without tilting the entire internal gear 71.

  That is, by being configured to be supported by the driving side plate 65 via the internal gear 71, when the driving side plate 65 is inclined with respect to the rear side plate 62, the fastening portion of the internal gear 71 with the driving side plate 65 is used. A certain seating surface 71a is fixed in a deformed state. Since the second carrier 72 is floatingly supported with respect to the internal gear 71 as described above, the deformation of the internal gear 71 can be canceled by the alignment of the second carrier 72. Further, since the internal gear 71 is made of resin, there is also a centering effect due to the deformation of the internal gear 71 itself. Therefore, even if the internal gear 71 is deformed by fastening with the drive side plate 65, the planetary gear reduction device 70 It is also possible not to affect the rotation fluctuation.

Example 4
Example 4 which is a fourth example of this embodiment will be described with reference to the drawings. FIG. 11 is a cross-sectional view of the photoreceptor driving device 10 according to the present embodiment. Here, portions having the same configurations as those in the first to third embodiments are denoted by the same reference numerals, and similar configurations and operations will be omitted as appropriate.
As shown in FIG. 11, in the planetary gear reduction device 70 of the present embodiment, the rear plate 62 is provided with a housing 75 coaxially with the drum shaft 50, and the housing 75 supports the bearing 51 of the photosensitive drum 1. doing. On the other hand, the seating surface 71a of the internal gear 71 of the planetary gear reduction device 70 is in contact with the housing 75 and is supported by the rear side plate 62 with screws. In this way, unlike the first to third embodiments, there is a configuration in which the planetary gear reduction device 70 is directly held on the rear side plate 62.

(Example 5)
Example 5 which is a fifth example of the present embodiment will be described with reference to the drawings. FIG. 12 is a cross-sectional view of the photoreceptor driving device 10 according to the present embodiment. Here, portions having the same configurations as those in the first to fourth embodiments are denoted by the same reference numerals, and similar configurations and operations will be omitted as appropriate.
As shown in FIG. 12, in the planetary gear reduction device 70 of the present embodiment, drum flanges 76 a and 76 b are press-fitted into both ends of the drum 52. A cylindrical boss portion is provided at the center of rotation of the drum flanges 76a and 76b, and the drum flange 76b is supported by the bearing 56 of the front side plate 61 through the boss. In addition, a gear is formed outside the cylinder of the boss portion provided on the drum flange 76 a and is configured to mesh with a spline joint 73 that functions as an output shaft of the planetary gear reduction device 70. Here, in the configuration of the present embodiment, the drum flange 76a side is a male joint and the spline joint 73 is a female joint, but there is no problem with the reverse configuration. In this manner, unlike Embodiments 1 to 4, it is possible to provide a configuration without a drum shaft.

What has been described above is merely an example, and the present invention has a specific effect for each of the following modes.
(Aspect A)
A driving device such as the photoconductor driving device 10 according to the present embodiment is arranged coaxially with the sun gear such as the first sun gear 31 that rotates by receiving a rotational driving force from a driving source such as the motor 20. Planetary gears such as a plurality of first planetary gears 33 that are arranged at equal intervals in the circumferential direction in the internal gear and mesh with the sun gear and the internal gears. A gear, a planetary gear that rotatably supports the carrier, such as a first carrier 34 that is coaxially rotatable with the sun gear and the internal gear, and a planetary gear that is held by the carrier and rotatably supports the planetary gear. A planetary gear reduction device 30 having at least two or more planetary gear mechanisms having a support shaft such as a first carrier pin 35 and having an output shaft such as an output shaft 40 in a final stage carrier such as a second carrier 38. Play A gear reduction device, a driven member such as the photosensitive drum 1 that is rotationally driven by the rotational driving force decelerated by the planetary gear reduction device, and the output shaft of the planetary gear reduction device that supports the driven member. And a driven body shaft such as a drum shaft 50 that transmits a rotational driving force from the sun gear, the internal gear, the carrier, the output shaft, and the driven body. The body axis and the central axis of the driven body are all arranged on the same axis, and at least one carrier is supported floatingly with respect to the internal gear, and each carrier can freely rotate the planetary gear. It is configured by one part provided with holes such as holes 34a and 34b for holding the support shaft.
According to this, as described in the first embodiment, the rotational driving force from the driving source such as the motor 20 is applied to the driven body such as the photosensitive drum 1 via the planetary gear reduction device such as the planetary gear reduction device 30. In the driving device such as the photoconductor driving device 10 that transmits to the driving device, it is possible to provide a driving device that can rotate the driven body with high accuracy.
(Aspect B)
In the aspect (A), the driving device such as the photoconductor driving device 10 according to this aspect is a carrier such as the second carrier 38 which is the final stage on the output side of the planetary gear speed reduction device 30 or the like. The rotation center of the internal gear such as the gear 32 is supported so as not to move.
According to this, as described in the first embodiment, the center of rotation of the carrier such as the second carrier 38 that is the final stage on the output side does not move relative to the internal gear such as the internal gear 32. Can be supported. As a result, the output shaft such as the output shaft 40 does not fluctuate due to alignment during rotational driving, and the degree of coaxiality between the driven shaft such as the drum shaft 50 and the output shaft can be minimized. It is possible to provide a driving device that drives the driven body with high accuracy.
(Aspect C)
In the driving device such as the photoconductor driving device 10 according to this aspect, in (Aspect A) or (Aspect B), the driven body shaft such as the drum shaft 50 is a part of a housing of an apparatus using the driving device. Both end portions are positioned and supported by a front plate such as the front plate 61 and a rear plate such as the rear plate 62 via bearings such as bearings 51 and 56, respectively. It is supported by a rear side plate and a driving side plate such as the driving side plate 63 held by the rear side plate.
According to this, as described in the first embodiment, the positional relationship with a plurality of members related to the driven body such as the photosensitive drum 1 can be determined with high accuracy. Further, the coaxiality between the output shaft of the drive source such as the motor output shaft 21 and the driven body shaft can be minimized, and the driven body can be driven with high accuracy.
(Aspect D)
A driving device such as the photoconductor driving device 10 according to the present aspect is the first planetary gear 33 or the like of the planetary gear reduction device such as the planetary gear reduction device 30 according to any one of (Aspect A) to (Aspect C). The material of the internal gears such as the planetary gear and the internal gear 32 is made of resin.
According to this, as described in the first embodiment, it is possible to minimize the rotational fluctuation caused by the meshing of the gears in the planetary gear reduction device such as the planetary gear reduction device 30.
(Aspect E)
The driving device such as the photoconductor driving device 10 according to the present aspect is the same as that in the aspect D, in which the planetary gear reduction device such as the planetary gear reduction device 70 is connected to the driving side plate 65 via the internal gear such as the internal gear 71. It is the structure supported by the said drive side board.
According to this, as described in the third embodiment, the deformation of the internal gear such as the internal gear 71 can be canceled by the alignment of the carrier such as the second carrier 72. Further, even if the internal gear 71 is deformed by fastening with the driving side plate such as the driving side plate 65, it is possible to prevent the rotation fluctuation of the planetary gear reduction device such as the planetary gear reduction device 70 from being affected.
(Aspect F)
A driving device such as the photoconductor driving device 10 according to this aspect includes an output shaft such as the output shaft 40 of the planetary gear reduction device such as the planetary gear reduction device 30 according to any one of (Aspect A) to (Aspect E). A connecting member such as a joint 41 that connects the driven shaft such as the drum shaft 50 is provided, and the connecting member is formed of a hollow cylindrical member.
According to this, as described in the first embodiment, a driven body such as the photosensitive drum 1 and a driven body shaft such as the drum shaft 50 can be attached and detached, and an apparatus such as a copying machine 500 using this driving apparatus. It can be positioned with high accuracy on the body. Moreover, the factor given to the coaxiality of the output shaft such as the output shaft 40 and the driven body axis can be only the straightness inside the cylindrical member, and the coaxiality can be minimized.
(Aspect G)
In any one of (Aspect A) to (Aspect E), the driving device such as the photosensitive member driving device 10 according to this aspect includes the output shaft of the planetary gear reduction device such as the planetary gear reduction device 70, the drum shaft 50, and the like. A connecting member for connecting the driven body shaft is provided, and the connecting member is a spline joint composed of a spline joint 73, a spline joint 74, and the like.
According to this, as described in the third embodiment, a driven body such as the photosensitive drum 1 and a driven body shaft such as the drum shaft 50 can be attached and detached, and an apparatus such as a copying machine 500 using this driving apparatus. It can be positioned with high accuracy on the body. Further, the coaxiality between the spline joint 73 that functions as an output shaft of a planetary gear reduction device such as the planetary gear reduction device 70 and the drum shaft 50 can be minimized during rotational driving.
(Aspect H)
A driving device such as the photoconductor driving device 10 according to this aspect includes an output shaft such as the output shaft 40 of the planetary gear reduction device such as the planetary gear reduction device 30 according to any one of (Aspect A) to (Aspect E). A driven body shaft such as the drum shaft 50 is integrally formed.
According to this, the effect as described in the second embodiment can be obtained.
(Aspect I)
A driving device such as the photoconductor driving device 10 according to this aspect is the first planetary gear 33 included in the planetary gear reduction device such as the planetary gear reduction device 30 according to any one of (Aspect A) to (Aspect H). The sliding portions between the planetary gears and the support shaft such as the first carrier 34 that rotatably supports the planetary gears are configured without bearings.
According to this, as described in the first embodiment, the assembly workability when the support shaft such as the carrier pin 35 and the planetary gear such as the planetary gear 33 are assembled in the carrier such as the carrier 34 is improved.
(Aspect J)
The image forming apparatus such as the copying machine 500 according to this aspect includes at least one driven body among driven bodies such as an image carrier such as the photosensitive drum 1 and a driving roller of an intermediate transfer belt such as the intermediate transfer belt 5. The drive device according to any one of (Aspect A) to (Aspect I) is provided.
According to this, the same effect as any one of (Aspect A) to (Aspect I) can be obtained.

DESCRIPTION OF SYMBOLS 1 Photosensitive drum 2 Charger 3 Static elimination lamp 4 Cleaning apparatus 5 Intermediate transfer belt 6 Primary transfer roller 7 Secondary transfer roller 8 Fixing roller pair 9 Developing device 10 Photoconductor drive device 11 Stretching roller (drive roller)
DESCRIPTION OF SYMBOLS 12, 13 Stretching roller 14 Tension roller 15 Transfer paper conveyance belt 16 Stretching roller pair 17 Optical writing device 18 Fixing device 19 Belt cleaning device 20 Motor 21 Motor output shaft 22 Internal tooth fixing flange 30 Planetary gear reduction device 31 1st Sun gear 32 Internal gear 33 First planetary gear 33a Needle bearing 34 First carrier 34a, 34b Hole 35 First carrier pin 36 Second sun gear 37 Second planetary gear 38 Second carrier 39 Second carrier pin 40 Output shaft 41 Joint 41a Slit 42 Internal gear cap 43, 43a, 43b Screw 50 Drum shaft 51, 56 Bearing 52 Drum 53a, b Drum flange 53a, 53b Drum flange 55 Joint 61 Front plate 62 Rear plate 63 Drive side plate 64 Stud 65 Drive Side plate 70 Planetary gear reduction device 71 Internal gear 71a Seat surface 72 Second carrier 73 Spline joint (female)
74 Spline joint (male)
75 Housing 76a, 76b Drum flange 80 Drive roller 81 Front holder 82 Rear holder 83 Front plate 84 Rear plate 85 Planetary gear speed reducer 86 Motor 100 Multi-function device body 101 Paper feed path 102 Registration roller 103 Paper feed path 104 Paper feed roller 105 Tray 106 paper discharge roller pair 107 paper discharge tray 108 separation roller 200 paper feed table 201 paper feed cassette 202 paper feed roller 203 separation roller 204 paper feed path 205 transport roller 300 scanner 301 contact glass 302 first travel body 303 second travel body 304 Imaging lens 305 Reading sensor 400 Automatic document feeder 401 Document table 500 Copying machine L Light beam

JP 2008-151868 A Japanese Patent Laid-Open No. 10-240069 JP 2001-330087 A

In order to achieve the above object, the invention according to claim 1 includes a sun gear that rotates by receiving a rotational driving force from a driving source, an internal gear that is arranged coaxially with the sun gear, A plurality of planetary gears arranged at equal intervals in the circumferential direction in an internal gear and meshing with the sun gear and the internal gear, and the sun gear and the internal gear while rotatably supporting the planetary gear. At least two stages of planetary gear mechanisms having a carrier that is coaxially rotatable and a support shaft that is supported by the carrier and that rotatably supports the planetary gear, and the output carrier is provided on the final stage carrier. A planetary gear reduction device, a driven body that is rotationally driven by a rotational driving force decelerated by the planetary gear reduction device, and a rotational driving force that supports the driven body and that is output from the output shaft of the planetary gear reduction device To the driven body In a drive device comprising a driven body shaft for transmission,
The sun gear, the internal gear, the carrier, the output shaft, the driven body axis, and the central axis of the driven body are all arranged on the same axis, and at least one carrier is the Floatingly supported with respect to the internal gear, the internal gear is positioned and held by the internal gear fixing member, the first stage sun gear is positioned on the internal gear, and at least one of the carriers is , mated and both end portions of the support shaft for rotatably supporting the planetary gears, holes for holding the support shaft is provided, the carrier and the planetary gear mechanism one lower planetary gear mechanism for having the carrier and the sun gear consists of 1 part, to configure each gears helical gear, setting twisting direction and the rotational direction of each helical gear as thrust moving force is generated toward the driven side to the sun gear The And has the 1 part provided with said and said sun gear carrier, the one having a boss-shaped portion protruding to the driven side.
In the present invention, the sun gear, the internal gear, the carrier, the output shaft of the planetary gear reduction device, the driven body shaft, and the central axis of the driven body are all arranged on the same axis, so that the drive source to the driven body The coaxiality can be minimized. Therefore, the positioning accuracy of the planetary speed reduction device and the drive motor with respect to the driven body and the positioning accuracy of the positioning and holding of the driven body and the main body device can be increased, and the driven body can be driven with high accuracy. Further, since one or more carriers are supported in a floating manner, even if the planetary gears and internal gears supported by the carriers have poor gear accuracy, the carriers are aligned according to the meshing, and the gears are arranged on the output shaft side. It is possible to suppress the rotation unevenness due to the gear accuracy. Further, the carrier and the planetary gear mechanism provided with the carrier are composed of one component of the sun gear of the lower planetary gear mechanism, and the holes are fitted and held with both ends of the support shaft that supports the planetary gear. By providing, the inclination of the support shaft that supports the planetary gear can be minimized. That is, the positional accuracy of the positioning and holding of the support shaft of the planetary gear can be increased, and the occurrence of rotation unevenness due to one rotation of the planetary gear can be suppressed.

Claims (10)

A sun gear that rotates in response to a rotational driving force from a drive source; an internal gear that is coaxially disposed with the sun gear; and the sun gear that is disposed at equal intervals in the circumferential direction within the internal gear. A plurality of planetary gears meshing with a gear and the internal gear, a carrier that rotatably supports the planetary gear and that is rotatable coaxially with the sun gear or the internal gear, and the planet held by the carrier A planetary gear speed reducer having at least two or more planetary gear mechanisms having a support shaft for rotatably supporting the gear, and having an output shaft on a carrier at the final stage;
A driven body that is rotationally driven by a rotational driving force decelerated by the planetary gear reduction device;
A drive device comprising: a driven body shaft that supports the driven body and transmits a rotational driving force from the output shaft of the planetary gear speed reducer to the driven body;
The sun gear, the internal gear, the carrier, the output shaft, the driven body axis, and the central axis of the driven body are all arranged on the same axis, and at least one carrier is the Floating supported against the internal gear,
Each carrier is constituted by one part which is fitted with both end portions of a support shaft that rotatably supports the planetary gear and is provided with a hole for holding the support shaft. The drive device according to claim 1,
The drive device characterized in that the carrier which is the final stage on the output side of the planetary gear reduction device is supported so that the rotation center of the carrier does not move with respect to the internal gear. The drive device according to claim 1 or 2,
The driven body shaft is positioned and supported at both ends via bearings on a front plate and a rear plate which are part of a housing of a device using a drive device,
The planetary gear speed reduction device is supported by the rear side plate and a drive side plate held by the rear side plate. In the drive device according to any one of claims 1 to 3,
The planetary gear reduction device, wherein the planetary gear and the internal gear are made of resin. The drive device according to claim 4, wherein
The planetary gear reduction device is configured to be supported by the drive side plate via the internal gear. The drive device according to any one of claims 1 to 5,
A drive device comprising a connecting member for connecting the output shaft of the planetary gear speed reducer and the driven body shaft, wherein the connecting member is formed of a hollow cylindrical member. The drive device according to any one of claims 1 to 5,
A driving device comprising: a connecting member for connecting the output shaft of the planetary gear speed reducer and the driven body shaft, wherein the connecting member is a spline joint. The drive device according to any one of claims 1 to 5,
A drive device characterized in that an output shaft and a driven body shaft of the planetary gear reduction device are integrally formed. The drive device according to any one of claims 1 to 8,
A drive unit, wherein a sliding portion between each planetary gear included in the planetary gear reduction device and a support shaft that rotatably supports the planetary gear is configured without bearings.   The drive device according to any one of claims 1 to 9 is provided as a drive device for at least one of the driven members such as an image carrier and a driving roller of an intermediate transfer belt. An image forming apparatus.

Images