JP2014040843A - Driving device and image forming apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an inexpensive driving device capable of reducing fluctuation of a rotating speed of a driven body by suppressing force to move a carrier of an epicycle reduction gear to the thrust direction.SOLUTION: In a driving device, a twisting direction and a rotating direction of each helical gear are set so that thrust moving force toward a driving motor 111 side is generated on a secondary sun gear 131 integrated with a first carrier 123 when the driving motor 111 is rotationally driven, and a projecting portion 136 of the secondary sun gear 131 is brought into contact with a second carrier 133 at a downstream side in the transmitting direction of the rotating driving force from the driving motor 111, by the thrust moving force of the second sun gear 131 integrated with the first carrier 123 at an upstream side. The driving device includes urging means for urging the first carrier 123 to a driving motor 111 side through a drum shaft 70, a joint 171 and an output shaft 138, by increasing a spring constant of a pressure spring 85 of positioning means for positioning a photosensitive drum 40 in the thrust direction.

Description

  The present invention relates to a driving device including a planetary gear reduction device that reduces and transmits the rotational driving force of a driving source to a rotational speed required by a driving target, and a copying machine, a printer, The present invention relates to an image forming apparatus such as a facsimile.

  2. Description of the Related Art Conventionally, an image forming apparatus such as a copying machine, a printer, a facsimile, or the like is known that includes a plurality of rotating bodies. In an electrophotographic image forming apparatus, for example, an image carrier such as a photosensitive drum, a driving roller for driving a belt member such as an intermediate transfer belt or a transfer belt, a conveyance roller for conveying a recording material, etc. A rotating body is used.

  In general, high rotational accuracy is required to drive such a rotating body. Therefore, a drive that transmits a rotational driving force from a driving source to a driven body, which is a rotating body to be driven, with a small fluctuation in rotational speed. An apparatus is desired. When fluctuations occur in the surface moving speed of a driving roller or the like that rotationally drives the photosensitive drum or the intermediate transfer belt, jitter and density unevenness occur on the output image. That is, when the rotational speed fluctuation continues at a certain frequency on the driving roller that rotationally drives the photosensitive drum and the intermediate transfer belt, periodic density unevenness occurs in the entire image, which is visually observed as a banded banding. The rotational speed variation of the photosensitive drum causes a sub-scanning position shift of the exposure line of the writing system, or a sub-scanning position shift during the primary transfer of the toner image from the photosensitive drum to the intermediate transfer belt. . Further, fluctuations in the rotational speed of the driving roller that rotationally drives the intermediate transfer belt cause a sub-scanning position shift between primary transfer and secondary transfer. The image quality is significantly deteriorated by banding caused by the rotation speed fluctuation.

  In many cases, a plastic gear formed by injecting molten resin is used for a driving device that transmits a rotational driving force of a driving source to a driving roller that drives a photosensitive drum or an intermediate transfer belt. Compared with metal gears, plastic gears have the advantages of self-lubricating, low noise during use, light weight, high corrosion resistance, low cost and high mass productivity. On the other hand, there are disadvantages in that durability (wear resistance), high accuracy, and high rigidity are inferior to those of metal gears. In view of these advantages and disadvantages, a configuration using a planetary gear reduction device is known so that sufficient durability can be obtained even when a plastic gear is used.

There is also known a configuration in which a helical gear is used for each gear in order to improve the rotation accuracy by suppressing the meshing vibration of the planetary gear reduction device and to reduce the noise.
Patent Document 1 describes the configuration of the following planetary gear reduction device (planetary gear reduction device) using helical gears for each gear. A planetary gear reduction device having a two-stage configuration in which an internal gear is fixed, and a first-stage sun gear (hereinafter referred to as a first sun gear) as an input side to which a drive source is transmitted. (Hereinafter referred to as the second carrier) is the output side that transmits the driving force to the driven body. A spherical protrusion is formed on the end face on the output side on the axis of the second stage sun gear (hereinafter referred to as the second sun gear) provided integrally with the first stage carrier (hereinafter referred to as the first carrier). Is provided. Further, the outer circumference of the second carrier is sandwiched between the two inner casings of the first stage and the second stage from both sides and integrated with screws through the cross roller bearing on the inner peripheral surface of the opposite casing. The surface is supported.

  In a configuration in which a helical gear is used for each gear of the planetary gear speed reducer, a thrust force (hereinafter referred to as a thrust moving force) is generated by the torsion angle of the helical gear, and the direction of the thrust moving force generated by each gear is Try to move. In particular, when a plurality of stages are used to increase the reduction ratio of the planetary gear speed reduction device, the carrier except for the final stage is configured integrally with the sun gear, so that the carrier is in a direction in which the sun gear provided integrally receives the force. Try to move. Along with this movement of the carrier, a relative displacement in the thrust direction occurs between the planetary gear rotatably held by the carrier, the sun gear, and the internal gear, and a single contact occurs at each meshing portion, resulting in rotational accuracy. May decrease and the rotational speed fluctuation of the driven body may increase.

  In the configuration of Patent Document 1, the thrust moving force from the second sun gear to the driven body acting on the second carrier is transmitted through the outer peripheral surface of the second carrier, the cross roller bearing, the inner peripheral surface of the casing, and the screw. Thus, the screw is transmitted to the casing on the other end side of the screw. By transmitting the thrust movement force in this way, the movement of each carrier in the thrust direction toward the driven body is suppressed, and the relative displacement in the thrust direction between each planetary gear and the internal gear that meshes with each other is suppressed. It is thought that fluctuations in the rotational speed of the body can be reduced.

However, in order to regulate the movement of the second carrier in the thrust direction with high accuracy, the second carrier that transmits the thrust moving force according to the magnitude of the thrust moving force acting on the second carrier, the cross roller bearing, and each casing It is necessary to increase the rigidity of the screw in the thrust direction. That is, according to the magnitude of the thrust movement force acting on the second carrier, it is necessary to increase the rigidity in the thrust direction of each member that resists this thrust movement force. However, there is a possibility that the cost of the planetary gear reduction device may increase due to the increase in rigidity in the thrust direction of each member that resists the thrust moving force acting on the second carrier.
Therefore, the drive device including the planetary gear reduction device described in Patent Document 1 is also highly likely to increase in cost.

  The present invention has been made in view of the above problems, and its object is to reduce the rotational speed fluctuation of the driven body by suppressing the force to move the carrier of the planetary gear speed reducer in the thrust direction. Is to provide a device.

  In order to achieve the above object, an invention according to claim 1 is a planetary gear mechanism having a sun gear that rotates by receiving a rotational driving force from a driving source, and an internal gear that is fixed in rotation. A planetary gear reduction device having at least two or more stages, each gear being constituted by a helical gear, and having an output shaft on the final stage carrier, and a driven body shaft that supports the driven body and is connected to the output shaft And a twisting direction and a rotation direction of each helical gear so that a thrust moving force toward the driven body is generated in a sun gear provided integrally with a carrier. The thrust moving force is transmitted to a carrier disposed on the driven body side, and biasing means for biasing the last stage carrier from the driven body shaft side toward the driving source side Having established It is an feature.

The present invention biases the thrust moving force acting on the last stage carrier toward the driven body, that is, the force to move each carrier toward the driven body side toward the driving source side. The biasing force of the biasing means can be canceled and suppressed.
In this way, by suppressing the force to move each carrier to the driven body side, the movement of each carrier in the thrust direction to the driven body side is suppressed, and each planetary gear engages with each internal gear. The relative displacement in the thrust direction can be suppressed, and the rotational speed fluctuation of the driven body can be reduced.
Further, it is possible to suppress an increase in the cost of the planetary gear speed reduction device due to increasing the rigidity in the direction of each member against the thrust moving force acting on the driven body acting on the last stage carrier.

  The present invention can provide an inexpensive drive device that can reduce the rotational speed fluctuation of the driven body by suppressing the force that moves the carrier of the planetary gear reduction device in the thrust direction.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic explanatory diagram of an image forming apparatus including a drum driving device that drives a photoreceptor according to an embodiment. Explanatory drawing of the planetary gear speed reducer which had in the drum drive device concerning one embodiment. The perspective explanatory view of the principal part of the drum drive concerning one embodiment. Cross-sectional explanatory drawing of the drum drive device which concerns on one Embodiment.

  Hereinafter, an embodiment in which the present invention is applied to an electrophotographic color copying machine (hereinafter referred to as a copying machine 500), which is an image forming apparatus, will be described with reference to the drawings. First, an outline of the copying machine 500 of this embodiment will be described. FIG. 1 is a schematic configuration diagram of a copier 500 including a drum driving device 110 that drives the photosensitive drum 40 according to the present embodiment.

  In FIG. 1, reference numeral 100 denotes a copying machine main body, reference numeral 200 denotes a paper feed table on which the copying machine is placed, reference numeral 300 denotes a scanner mounted on the copying machine main body 100, and reference numeral 400 further denotes an automatic document transport mounted thereon. Device (ADF). This copier is a tandem type electrophotographic copier that employs an intermediate transfer (indirect transfer) system.

  In the center of the copying machine main body 100, an intermediate transfer belt 10 including a belt which is an intermediate transfer member serving as an image carrier is provided. The intermediate transfer belt 10 is stretched around a first support roller 14, a second support roller 15, and a third support roller 16 as three support rotating bodies, and rotates and moves in the clockwise direction in the figure. On the left side of the second support roller 15 in the figure, an intermediate transfer belt cleaning device 17 for removing residual toner remaining on the intermediate transfer belt 10 after image transfer is provided. Further, a belt portion stretched between the first support roller 14 and the second support roller 15 has a yellow (Y), magenta (M), cyan (C), black ( A tandem image forming unit 20 in which the four image forming units 18 of K) are arranged side by side is arranged oppositely. In the present embodiment, the third support roller 16 is a drive roller.

An exposure device 21 as a latent image forming unit is provided above the tandem image forming unit 20.
A secondary transfer device 22 as a second transfer unit is provided on the opposite side of the tandem image forming unit 20 with the intermediate transfer belt 10 interposed therebetween. In the secondary transfer device 22, a secondary transfer belt 24, which is a belt member as a recording medium conveying member, is stretched between a roller 23a and a roller 23b. The secondary transfer belt 24 is provided so as to be pressed against the third support roller 16 via the intermediate transfer belt 10. The secondary transfer device 22 transfers the toner image on the intermediate transfer belt 10 to a sheet P that is a recording medium.

  A fixing device 25 for fixing the toner image transferred onto the sheet P is provided on the left side of the secondary transfer device 22 in the drawing. The fixing device 25 has a configuration in which a pressure roller 27 is pressed against a fixing belt 26 that is a belt member. The secondary transfer device 22 described above also has a sheet transport function for transporting the sheet P after the toner image transfer to the fixing device 25. Of course, a transfer roller or a non-contact charger may be disposed as the secondary transfer device 22, and in such a case, it is difficult to provide this recording medium conveyance function together. In the present embodiment, a sheet that reverses the sheet P so as to record an image on both sides of the sheet P in parallel with the above-described tandem image forming unit 20 below the secondary transfer device 22 and the fixing device 25. A reversing device 28 is also provided.

  When copying using the copying machine 500, a document is set on the document table 30 of the automatic document feeder 400. Alternatively, the automatic document feeder 400 is opened, a document is set on the contact glass 32 of the scanner 300, and the automatic document feeder 400 is closed and pressed. Thereafter, when a start switch (not shown) is pressed, when the document is set on the automatic document feeder 400, the document is conveyed and moved onto the contact glass 32. On the other hand, when an original is set on the contact glass 32, the scanner 300 is immediately driven. Next, the first traveling body 33 and the second traveling body 34 travel.

Then, the first traveling body 33 emits light from the light source and further reflects the reflected light from the document surface toward the second traveling body 34, and is reflected by the mirror of the second traveling body 34 and passes through the imaging lens 35. The document is placed in the reading sensor 36 and the original content is read.
In parallel with this document reading, a third support roller 16 as a driving roller is rotationally driven by a driving motor as a driving source (not shown). As a result, the intermediate transfer belt 10 moves in the clockwise direction in the drawing, and the first support roller 14 and the second support roller 15 rotate along with the movement. At the same time, in each of the image forming units 18Y, 18M, 18C, and 18K, the photosensitive drums 40Y, 40M, 40C, and 40K as latent image carriers are respectively driven for corresponding photosensitive drums (not shown). It is rotated by the drum drive device 110Y, M, C, K which is a device. Then, on each of the photosensitive drums 40Y, 40M, 40C, and 40K, by using color-specific information on yellow, magenta, cyan, and black, each is exposed and developed to form a single-color toner image (visualized image).

The toner images formed on the photoconductive drums 40Y, 40M, 40C, and 40K are sequentially transferred onto the intermediate transfer belt 10 so as to overlap each other, and a composite color image is formed on the intermediate transfer belt 10.
In parallel with such image formation, one of the paper feed rollers 42 of the paper feed table 200 is selectively rotated, the sheet P is fed out from one of the paper feed cassettes 44 provided in the paper bank 43 in multiple stages, and the separation roller 45 To separate them one by one and put them in the paper feed path 46. Then, the sheet P put in the paper feed path 46 is transported by the transport roller 47 and guided to the paper feed path in the copying machine main body 100, and is abutted against the registration roller 49 and stopped. Alternatively, the manual feed roller 50 is rotated to feed out the sheets P on the manual feed tray 51, separated one by one by the separation roller 52, put into the manual feed path 53, and abutted against the registration roller 49 and stopped. Then, the registration roller 49 is rotated in synchronization with the composite color image on the intermediate transfer belt 10, the sheet P is fed between the intermediate transfer belt 10 and the secondary transfer device 22, and transferred by the secondary transfer device 22. The color image is transferred onto the sheet P.

After the image transfer, the sheet P is conveyed by the secondary transfer belt 24 and sent to the fixing device 25. The fixing device 25 applies heat and pressure to fix the transferred image, and then the image is transferred by the switching claw 55 and discharged. The paper is discharged at 56 and stacked on the paper discharge tray 57. Alternatively, it is switched by the switching claw 55 and put into the sheet reversing device 28, where it is reversed and guided again to the transfer position, and the image is recorded also on the back surface of the sheet P, and then discharged onto the discharge tray 57 by the discharge roller 56. To do.
The intermediate transfer belt 10 after the image transfer is removed by the intermediate transfer belt cleaning device 17 to remove residual toner remaining on the intermediate transfer belt 10 after the image transfer, so that the tandem image forming unit 20 can prepare for another image formation. Here, the registration roller 49 is generally used while being grounded, but it is also possible to apply a bias for removing paper dust on the sheet P.

  This copying machine 500 can be used to make a black and white copy. In that case, the intermediate transfer belt 10 is separated from the photosensitive drums 40Y, 40M, 40C by means not shown. These photosensitive drums 40Y, 40M, 40C are temporarily stopped from driving. Then, only the black photosensitive drum 40K is brought into contact with the intermediate transfer belt 10 to perform image formation and transfer.

  Next, the planetary gear speed reduction devices 120Y, M, and C used for the drum driving devices 110Y, 110M, 110C, and 110K that respectively rotate and drive the photosensitive drums 40Y, 40M, 40C, and 40K, which are features of the present embodiment. , K will be described with reference to the drawings. Here, the configurations of the drum driving devices 110Y, 110M, 110K, and the planetary gear speed reduction devices 120Y, 120M, 120C, and 120K are substantially different only in the color of the toner image formed on each photosensitive drum 40. It is the same. Therefore, in the following description, the symbols Y, M, C, and K are omitted unless otherwise specified. FIG. 2 is an explanatory diagram of the planetary gear reduction device 120 included in the drum driving device 110 according to the present embodiment.

  As shown in FIG. 2, the planetary gear speed reduction device 120 of the present embodiment used in the drum driving device 110 uses a 2KH type two-stage planetary gear mechanism. A motor shaft 112 that is an output shaft of the drive motor 111 that is a drive source is connected to a first-stage sun gear (hereinafter referred to as a first sun gear) that is an input shaft of the first-stage planetary gear mechanism in the planetary gear reduction device 120. 121) is formed coaxially and integrally. The first stage planetary gear (hereinafter referred to as the first planetary gear 122) that meshes with the first sun gear 121 and the tooth profile 141 of the internal gear 140 provided coaxially with the first sun gear 121 is the first stage gear. The carrier (hereinafter referred to as the first carrier 123) is rotatably supported. Specifically, the first carrier pin (hereinafter referred to as the first carrier pin 124) fixed to the first carrier 123 is rotatably supported.

  When the first sun gear 121 is rotationally driven, the first planetary gear 122 rotates around the outer periphery of the first sun gear 121 while rotating by the meshing of the first sun gear 121 and the tooth profile 141 of the internal gear 140. It has come to revolve. Further, the first planetary gear 122 is concentrically arranged at three places or more in order to balance rotation and share torque. In the present embodiment, the first planetary gears 122 are respectively arranged at positions divided into four equal parts in the circumferential direction.

  The first carrier 123 that supports the first planetary gear 122 is provided coaxially with the first sun gear 121 and the internal gear 140, and rotates at a reduced speed relative to the rotation of the first sun gear 121. Reduction ratio is acquired. A second-stage sun gear (hereinafter referred to as a second sun gear 131) provided at the rotation center of the first carrier 123 serves as an input to the second-stage planetary gear mechanism. The first carrier 123 does not have a rotation support portion, and performs floating rotation.

  Similarly, a second stage planetary gear (hereinafter referred to as a second planetary gear 132) that meshes with the second sun gear 131 and the tooth profile 141 of the internal gear 140 that is integrally formed up to the second stage is referred to as the second stage gear. A carrier (hereinafter referred to as a second carrier 133) is rotatably supported. Specifically, it is rotatably supported by a second stage carrier pin (hereinafter referred to as a second carrier pin 134) fixed to the second carrier 133. When the second sun gear 131 rotates, the second planetary gear 132 revolves around the outer periphery of the second sun gear 131 while rotating due to the meshing of the second sun gear 131 and the tooth profile 141 of the internal gear 140. It has become. In the present embodiment, the second planetary gears 132 are respectively arranged at positions that are divided into four equal parts in the circumferential direction. Further, an output shaft 138 is integrally provided on the second carrier 133 corresponding to the final stage.

Here, the configuration of the 2KH type planetary gear mechanism used in the planetary gear reduction device 120 of the present embodiment and the operation principle thereof will be described. One unit used in the 2KH type planetary gear mechanism is composed of the following four parts. They are a sun gear, a planetary gear, a planetary carrier that supports the revolving motion of the planetary gear, and an internal gear (outer gear).
Of the three elements that are sun gear rotation, planetary gear revolution (carrier rotation), and internal gear (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 2KH type two-stage structure that is the object of the present embodiment is classified into compound planetary gear mechanisms (two or more 2KH types), and there are two or more 2KH types. In each of the three elements, one element is coupled to each other, the remaining one is fixed, and the remaining two are used as an input shaft or an output shaft. In the planetary gear device 120 of the present embodiment, the internal gear 140 that is coupled to the first stage and the second stage is fixed, the first sun gear (first stage) is input, and the second carrier (second stage) ) Is assigned to the output.

The reduction ratio is expressed by the following formula 1 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.
(Formula 1)
Reduction ratio = Za1 / (Za1 + Zc1) × Za2 / (Za2 + Zc2)

  Moreover, the material of the main components of the planetary gear mechanism used in the planetary gear reduction device 120 of the present embodiment is configured as follows. The internal gear 140, the first planetary gear 122, the second planetary gear 132, the first carrier 123, and the second sun gear 131 integrated with the first carrier 123 are made of resin (POM or the like). Further, the second carrier 133, the output shaft 138 provided integrally with the second carrier 133, the first sun gear 121, the first carrier pin 124, and the second carrier pin 134 are also made of metal.

Next, the configuration of the planetary gear reduction device 120 and the drive motor 111 will be described in more detail.
First, the support by the internal gear fixing flange 114 of the internal gear 140 that also serves as the casing of the planetary gear reduction device 120 will be described with reference to FIG.
As shown in FIG. 2, the internal gear 140 has a tooth profile 141 having a coaxial internal tooth shape, and a seat surface 142 extending in the inner diameter direction of the tooth profile 141 on the input side. A hole having a boss 143 is provided around the center of the surface 142. In the internal gear 140, the boss portion 143 is fitted into a hole 115 provided in the internal gear fixing flange 114, and is fixed to the internal gear fixing flange 114 with a screw 153 at the seat surface 142. In this way, the boss portion 143 of the seating surface 142 of the internal gear 140 and the hole 115 provided in the internal gear fixing flange 114 are fitted together, thereby positioning the internal gear 140 and the internal gear fixing flange 114. Fixing can be reliably performed with a simple configuration.

Next, the support of the drive motor 111 by the internal gear fixing flange 114 and the configuration of the drive motor 111 will be described.
The motor shaft 112 of the drive motor 111 described above is supported by a motor fixing flange 113 via two bearings (not shown). By supporting the motor shaft 112 of the drive motor 111, the outer rotor that is the rotor of the DC brushless motor is supported. The motor fixing flange 113 is also provided with a stator core (not shown) of the drive motor 111, a motor drive circuit board, and the like.

  Further, as described above, the first sun gear 121 is formed by gear cutting on the motor shaft 112 of the drive motor 111. And in order to ensure the coaxial precision with the axis | shaft of the 1st sun gear 121 and the axis | shaft of the internal gear 140, the internal gear 140 and the motor fixing flange 113 are as follows with respect to the internal gear fixing flange 114 as follows. Positioned. A boss formed on the motor fixing flange 113 is positioned by fitting with an inlay in a hole having a boss 143 formed around the center of the seating surface 142 of the internal gear 140. As described above, the boss portion 143 of the internal gear 140 is positioned by fitting with a hole 115 provided in the internal gear fixing flange 114 and an inlay.

As described above, the internal gear 140 on the output side is fixed by screws 153 from the seating surface 142 of the internal gear 140 to the internal gear fixing flange 114. On the other hand, in the drive motor 111 on the input side, the motor fixing flange 113 is fixed to the internal gear fixing flange 114 with screws 154.
As described above, the internal gear 140 and the drive motor 111 are positioned with respect to the internal gear fixing flange 114.

Next, the configuration of the planetary gear reduction device 120 will be described in more detail.
An end cap 144 is fixed to an end portion of the internal gear 140 that is opposite to the internal gear fixing flange 114. When the planetary gear reduction device 120 is assembled to the internal gear fixing flange 114, the end cap 144 causes each planetary gear installed in the internal gear 140 and each carrier to drop out from the internal gear 140. It is used as a member for preventing this. Further, the end cap 144 rotatably supports the output shaft 138 via the output shaft bearing 145.

  Further, in the planetary gear reduction device 120 of the present embodiment, each gear is constituted by a helical gear in order to reduce the meshing vibration of each gear. However, when the meshing gears are helical gears, when the drive motor 111 is driven to rotate, the thrust carrier force acts on each gear, so that the first carrier 123 that supports floating is integrally provided. The second sun gear 131 moves with the thrust moving force. The direction in which the first carrier 123 moves is the direction toward the second carrier 133 for the following reason, that is, the direction in which each gear is twisted so that the first carrier 123 and the first sun gear 121 do not contact each other. And the rotation direction is set. When the first sun gear 121 is faster than the second sun gear 131 and the first sun gear 121 is made of metal, the first sun gear 121 and the first carrier 123 are rubbed. This is because the wear of the first carrier 123 becomes faster.

Since the moving direction of the first carrier 123 is set as described above, a hemispherical protrusion 136 is integrally formed at the center of the end surface of the second sun gear 131 to reduce the frictional resistance. Yes. In the planetary gear speed reduction device 120 of the present embodiment, the difference in rotational speed between the first carrier 123 and the second carrier 133 can be kept small, so that the hemispherical protrusion 136 is made of the resin-made second sun gear 131 as described above. It is formed integrally with the end face of.
However, the present invention is not limited to such a configuration. For example, when the difference in rotational speed between the first carrier 123 and the second carrier 133 is large, if necessary, the hemispherical protrusion 136 that contacts the second carrier 133 is made of metal and the second sun gear 131 is You may comprise so that it may fit and be integrated by fitting in the formed recessed part.

Next, the structure of the other part of the drum drive device 110 of this embodiment will be described with reference to FIGS. 3 and 4. FIG. 3 is a perspective explanatory view of a main part of the drum driving device 110 according to the present embodiment, and FIG. 4 is a cross-sectional explanatory view of the drum driving device 110 according to the present embodiment.
As shown in FIG. 3, the drum driving device 110 mainly includes a driving motor 111 as a driving source, a planetary gear reduction device 120, a joint 171 as a connecting member, and a drum shaft 70 as a driven shaft. Further, as shown in FIG. 4, the output shaft 138 of the planetary gear reduction device 120 is connected and fixed by a drum shaft 70 and a joint 171. Here, in the following description, the front side of the copying machine main body 100, that is, the side away from the driving motor 111 that is a driving source is the front side, and the rear side of the copying machine main body 100, that is, the driving motor 111 side that is the driving source is the rear side. Will be described.

  A second drum bearing 82 and a third drum bearing 83 are press-fitted into the drum shaft 70. The rear plate 164 fixed to the rear side in the casing of the copying machine main body 100 is provided with a hole that fits with the peripheral surface of the third drum bearing 82 and restricts the radial direction. The third drum bearing is provided in this hole. 83 is fitted and positioned. Further, a first drum bearing 81 for restricting the radial direction of the drum shaft 70 is fixed to a face plate 163 fixed to the front plate 161 fixed to the front side in the casing of the copying machine main body 100, and this first drum bearing is fixed. The vicinity of the tip end of the drum shaft 70 is inserted into the inner peripheral portion 81 to be positioned for support. That is, the drum shaft 70 is positioned and supported at both ends on the face plate 163 and the rear plate 164, which are part of the casing of the copying machine main body 100, in the radial direction via the first drum bearing 81 and the third drum bearing 83, respectively. The The photosensitive drum 40 is positioned and supported with respect to the copying machine main body 100 via the drum shaft 70.

By positioning in the radial direction as described above, the photosensitive drum 40 is relatively moved through a member (for example, the intermediate transfer belt 10), which requires relative positional accuracy, and the front plate 161 and the rear plate 164. The positional relationship is determined. Therefore, the positional relationship in the radial direction with a plurality of members related to the photosensitive drum 40 can be determined with high accuracy.
On the other hand, in the thrust direction positioning, the side surface of the third drum bearing 83 press-fitted into the drum shaft 70 is abutted against a restriction plate 165 provided to close the rear side (drive source side) of the hole in the rear side plate 164. Position. The force at the time of abutting is given by a pressure spring 85 provided on the front side of the drum shaft 70.

  As described above, the radial positioning of the drum shaft 70 is performed via the first drum bearing 81 and the third drum bearing 83, and the movement of the second carrier 133 is regulated by the third drum bearing 83, so that The following actions and effects can be obtained. The photosensitive drum 40 can be positioned in the radial direction and the thrust direction with respect to the copying machine main body 100 with high accuracy, and the frictional resistance between the side surface of the third drum bearing 83 and the regulating plate 165 that is the position where the positioning in the thrust direction is performed. Can be reduced.

Next, fixing of the main body of the planetary gear reduction device 120 will be described.
The planetary gear speed reduction device 120 is configured such that the internal gear fixing flange 114 is screwed to the driving side plate 116 that is positioned and fixed to the rear side plate 164 that is fixed to the casing of the copying machine main body 100 via the stud 150. It is positioned and fixed with respect to the copying machine main body 100.

Next, the configuration of the photosensitive drum unit 60 will be described.
A rear drum flange 66 and a front drum flange 64 on the rear end side are fixed to the end of the photosensitive drum 40 in the axial direction (thrust direction), and these drum flanges are supported by the drum shaft 70. ing. The rear drum flange 66 is connected to the drum shaft 70 by a serration coupling 72, and when the drum shaft 70 rotates, the photosensitive drum 40 rotates synchronously. The serration coupling 72 is provided with a male shape 71 on the drum shaft 70 side and a female shape 67 on the rear drum flange 66 side, and has a tapered shape whose diameter increases from the front side to the rear side of the drum shaft 70. In the unit case 61 that supports the photosensitive drum 40, among the members constituting the image forming unit 18, the photosensitive drum 40, a charger, a developing device, a photosensitive member cleaning device, a static elimination lamp, and the like are accommodated. .

  The rear side of the unit case 61 is supported by a second drum bearing 82 fixed to the drum shaft 70, and the rear drum flange 66 is also supported by the second drum bearing 82, so that the photosensitive drum 40 and the unit are supported. The case 61 is positioned. Further, on the front side of the unit case 61, the boss portion 65 of the front drum flange 64 is configured to be fitted to the unit case 61 and to be rotatable. The drum shaft 70 is further provided with another third drum bearing 82 at a position where the drum shaft 70 is fitted to the rear plate 164 which is a part of the casing of the copying machine main body 100, and is positioned with respect to the rear plate 164. . The front plate 161 is provided with a notch 162 that is an opening for use in attaching and detaching the photosensitive drum unit 60, and the face plate 163 is fixed thereto.

  The front end of the drum shaft 70 is rotatably supported by the face plate 163 via the first drum bearing 81. Then, by removing the face plate 163 from the photoconductor drum unit 60, it is possible to replace the photoconductor drum 40 that is attached and detached. When the photosensitive drum unit 60 is mounted, the photosensitive drum 40 is moved by the pressure spring 85 provided between the third drum bearing 83 fixed to the face plate 163 and the boss portion 65 of the front drum flange 64. The pressure is applied in the thrust direction toward the drive source side. Then, the rotational direction and the thrust direction are positioned at the connecting portion of the tapered serrated coupling 72. Further, the drum shaft 70 is positioned in the radial direction by fitting the outer peripheral surface of the third drum bearing 83 with the inner peripheral surface of the hole of the rear plate 164, and the thrust direction of the third drum bearing 83 is adjusted to the restriction plate 165. The side faces abut and are positioned.

  The pressure spring 85 provided on the front side of the drum shaft 70 is supported by a spring receiver 84 having a hole through which the drum shaft 70 is formed. When the face plate 163 is fixed to the front plate 161, the first drum bearing is provided. The spring receiver 84 is pushed into the rear side 81. Then, a force for compressing the pressure spring 85 is generated, and the front drum flange 64 is pushed to the rear side (drive source side) to position the photosensitive drum 40 in the thrust direction. That is, the pressure spring 85 and the spring receiver 84, the first drum bearing 81, and the front drum flange 64 function as a thrust direction positioning means for the photosensitive drum 40 as a driven body.

In the drum driving device 110 according to the present embodiment, the positioning means in the thrust direction of the photosensitive drum 40 biases the second carrier 133 that is the last stage carrier toward the drive motor 111 that is the driving source. It is also used as a force means. In this way, the drum driving device 110 can be simplified by combining the positioning means of the photosensitive drum 40 and the urging means of the second carrier 133 as compared with the configuration in which the positioning means and the urging means are separately provided. Can be configured at low cost.
Further, the face plate 163 that supports one end side of the drum shaft 70 is fixed to the cutout hole 162 of the front plate 161 that removes and pulls out the photoconductor drum unit 60 that encloses the photoconductor drum 40, whereby the second carrier 133 is driven by the drive motor 111. An urging force that urges to the side is generated. Since the urging force of the urging means can be generated in this way, the work for exchanging the photoconductive drum 40 can be simplified and facilitated, and the convenience of the operator for exchanging the photoconductive drum 40 can be improved. Can be improved.

  Next, by using a helical gear for each gear of the planetary gear reduction device 120, the force acting on the second carrier 133 which is the last stage carrier and the movement of the second carrier 133 by this force are energized as described above. The structure suppressed by the urging | biasing force of a means is demonstrated. In FIG. 4, the direction of the force of the thrust direction applied to each helical gear and each part is shown by arrows ag. Further, as described above, in the planetary gear speed reduction device 120 of the present embodiment, the second sun provided integrally with the first carrier 123 so that the first carrier 123 moves toward the second carrier 133 side, that is, the front side. The gear 131 is configured so that a thrust moving force acts on the gear 131.

  Specifically, first, the first sun gear 121 (first stage) sets the rotational direction and the helical angle direction of the helical teeth so that a thrust moving force is generated in the direction of arrow a toward the front side. However, the first sun gear 121 is directly geared to the motor shaft 112 and is not moved because it is fixed to the drive motor 111. The first planetary gear 122 meshed with the first sun gear 121 generates a thrust moving force in the direction opposite to the arrow a direction due to meshing with the first sun gear 121. However, the meshing with the internal gear 140 generates a thrust moving force in the direction of arrow b toward the rear side at the meshing portion of the internal gear 140, and the thrust movement in the direction opposite to the arrow b direction on the first planetary gear 122. Power is generated. Since the magnitude of the thrust moving force generated in the first planetary gear 122 by these two meshing is almost equal, they cancel each other out. The first planetary gear 122 cancels the thrust moving force by meshing with the first sun gear 121 and the internal gear 140. Then do not move.

  In addition, a thrust moving force is generated in the direction of the arrow c toward the front side in the second sun gear 131 provided integrally with the first carrier 123 that rotates by the revolution of the first planetary gear 122. As a result, the first carrier 123 that is provided integrally with the second sun gear 131 and is supported in a floating manner, and the first planetary gear 122 that is rotatably held by the first carrier 123 are the second carrier 133. Move to the side. Then, the protrusion 136 at the tip of the second sun gear 131 pushes the second carrier 133 to the photosensitive drum 40 side (front side) as the driven body, and the force in the direction of the arrow e toward the front side, that is, the direction of the arrow e direction. A thrust moving force is applied to the second carrier 133.

At this time, a thrust moving force is generated in the second planetary gear 132 that meshes with the second sun gear 131 and the internal gear 140, but the meshing with the second sun gear 131 and the internal gear 140 is the same as the first planetary gear 122. The thrust moving force generated by
Similarly to the meshing portion of the internal gear 140 that meshes with the first planetary gear 122, a thrust moving force in the direction of the arrow d toward the rear side is generated at the meshing portion of the internal gear 140 that meshes with the second planetary gear 132. . As described above, the internal gear 140 is a meshing portion with the first planetary gear 122 and the second planetary gear 132, and a thrust moving force toward the rear side is generated at two locations indicated by arrows b and d, respectively. It is fixed to the gear fixing flange 114 and is compressed but does not move greatly.

  On the other hand, a thrust moving force in the direction of arrow e acts on the second carrier 133 pushed from the second sun gear 131 and the output shaft 138 provided integrally with the second carrier 133. At this time, if the second carrier 133 and the output shaft 138 are configured not to apply an urging force in the direction opposite to the arrow e direction, the second carrier 133 and the output shaft 138 move toward the front as follows. It will be. Here, as a configuration in which an urging force in the direction opposite to the direction of the arrow e is not applied, the rotational driving force of the output shaft 138 is changed using a coupling that can slide in the thrust direction instead of the joint 171 shown in FIG. A configuration for transmitting to the drum shaft 70 is conceivable. In such a configuration, what controls the movement of the second carrier 133 and the output shaft 138 in the thrust direction is the internal gear 140 connected via the output shaft bearing 145 and the end cap 144. The thrust moving force acting in the direction of arrow e acting on the second carrier 133 and the output shaft 138 and the force in the direction opposite to the direction of arrow e, that is, the force in the direction of arrow g, are equal in magnitude. It acts on the internal gear 140.

  As described above, when a force in the direction of the arrow g is applied at the connection portion between the end cap 144 and the internal gear 140, the thrust movement of the engagement portion of the first planetary gear 122 and the second planetary gear 132 with the arrows b and d is performed. A tensile force acts on the internal gear 140 in relation to the force (compression force). Then, the internal gear 140 is deformed so as to extend in the vicinity of a region where the second planetary gear 132 meshes with the internal gear 140 at a parallel point between the compression force indicated by the arrows b and d and the pulling force indicated by the arrow g. As a result, one-side contact or the like is likely to occur at the meshing portion with the second planetary gear 132. When one-side contact or the like occurs at the meshing portion of the second planetary gear 132 and the internal gear 140, the rotational accuracy of the output shaft 138 decreases, and the rotational speed fluctuation of the photosensitive drum 40 that is the driven body increases.

  Further, in the configuration using a normal bearing as the output roller bearing 145 in which the rigidity in the thrust direction is not as high as that in the cross roller bearing described in Patent Document 1, the second in the portion of the output bearing 145 is used. Movement of the carrier 133 and the output shaft 138 occurs. As a result, not only the second carrier 133 and the output shaft 138 but also the second planetary gear 132 held by the second carrier 133, the first carrier 123, and the first planetary gear 122 held by the first carrier 123. Also occurs. When the movement of the second planetary gear 132 and the first planetary gear 122 occurs as described above, relative displacement in the thrust direction occurs between the planetary gears and the internal gears 140 that mesh with each other, and the planetary gears and the internal gears 140 are generated. One-sided contact or the like is likely to occur at the meshing portion. When one-side hit or the like occurs at the meshing portion between each planetary gear and the internal gear 140, the rotational accuracy of the output shaft 138 decreases, and the rotational speed fluctuation of the photosensitive drum 40, which is the driven body, increases.

  Further, as shown in FIG. 4, when the drum shaft 70 and the output shaft 138 are connected by the joint 171, when a thrust moving force toward the front side acts on the second carrier 133 and the output shaft 138, the connected drum shaft 70. Similarly, a thrust moving force toward the front side is also applied. As a result, the photosensitive drum 40, which is a driven member supported by the drum shaft 70, is moved in the thrust direction, and rotation unevenness is likely to occur, and the rotational speed fluctuation of the photosensitive drum 40 is likely to occur. .

  Therefore, in the present embodiment, an urging unit that urges the second carrier 133 that is the last stage carrier toward the drive motor 111 that is the driving source is provided, and acts on the second carrier 133 and the output shaft 138. We decided to suppress the thrust movement force. That is, the force to move each carrier to the photosensitive drum 40 side is canceled and suppressed by the urging force of the urging means that urges the second carrier 133 toward the drive motor 111 side. As the urging means, a configuration in which the second carrier 133 or the output shaft 138 is urged toward the drive motor 111 is also conceivable. In this embodiment, the photosensitive drum 40 is positioned in the thrust direction. It is also used as a positioning means for the photosensitive drum 40. In this way, the drum driving device 110 can be simplified and inexpensively configured as compared with a configuration in which positioning means and biasing means are separately provided.

  Specifically, in addition to the force for positioning the photosensitive drum 40, a force for reducing the thrust moving force toward the photosensitive drum 40 acting on the second carrier 133 is applied. In other words, the second carrier 133 and the second carrier 133 when the drum shaft 70 tries to move forward by the thrust moving force by making the spring constant of the pressure spring 85 constituting the positioning means larger than the spring constant required for the positioning means. The movement of the output shaft 138 is configured to be suppressed. In this way, by urging the second carrier 133 toward the drive motor 111 via the output shaft 138 and the joint 171 with the urging force of the urging means from the drum shaft 70 side that is the driven body shaft, A thrust moving force acting on the second carrier 133 can be suppressed.

  Therefore, an increase in the cost of the planetary gear speed reduction device 120 resulting from increasing the rigidity in the direction of the thrust of each member against the thrust moving force toward the photosensitive drum 40 acting on the second carrier 133 can be suppressed. Even if the reduced thrust moving force is transmitted to the internal gear 140 by using a bearing that does not have high rigidity in the thrust direction as the output bearing 145 that rotatably supports the output shaft 138 of the second carrier 133. The movement of the two carriers 133 in the thrust direction can be suppressed.

Moreover, the movement of the 1st carrier 123 which is contacting via the protrusion part 136 of the 2nd sun gear 131 can also be suppressed by suppressing the movement of the 2nd carrier 133. FIG.
Since the movement of each carrier in the thrust direction toward the driven body can be suppressed as described above, the relative displacement in the thrust direction between each planetary gear and the internal gear 140 that meshes with each other is suppressed, and the photosensitive member that is the driven body. The fluctuation in the rotational speed of the body drum 40 can be reduced.
Therefore, it is possible to provide an inexpensive drum driving device 110 that can suppress the rotational speed fluctuation of the photosensitive drum 40 by suppressing the force that moves each carrier of the planetary gear speed reduction device 120 in the thrust direction.

  In addition, the magnitude of the force acting in the direction of the arrow g, that is, the biasing force: g, is greater than the thrust moving force in the direction of the arrow e acting on the second carrier 133: e by the pressurizing spring 85 also serving as the positioning means. It can also be enlarged. Thus, by making the urging force: g larger than the thrust movement force: e (f> e), it is possible to more effectively suppress the force that moves each carrier of the planetary gear reduction device 120 in the thrust direction. Further, by making the biasing force: g larger than the thrust moving force: e (f> e), it is possible to prevent the second carrier 133 from moving and hitting the end cap 144 to deform the internal gear 140.

  Even when the urging force: g is greater than the thrust movement force: e (f> e), the movement of the drum shaft 70 toward the drive motor 111 is regulated as follows, and the planet is The movement of each carrier of the gear reduction device 120 toward the drive motor 111 can be prevented. It is to set the strength of the restricting plate 165 and the rear plate 164 provided on the rear plate 164 and the spring constant of the pressure spring 85 within an appropriate range for restricting the movement of the drum shaft 70 toward the drive motor 111. . By setting in this way, each carrier of the planetary gear speed reduction device 120 moves to the drive motor 111 side, and the gears mesh with each other. It is possible to prevent the rotation speed fluctuation from occurring.

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 sun gear such as a first sun gear 121 and a second sun gear 131 that rotates by receiving a rotational driving force from a drive source such as a drive motor 111; and an internal gear such as an internal gear 140 whose rotation is fixed; The planetary gear mechanism having at least two stages or more, each gear being constituted by a helical gear, the planetary gear reduction device 120 having an output shaft such as the output shaft 138 on the final stage carrier such as the second carrier 133, etc. A planetary gear speed reduction device, a drum drive device 110 that supports a driven member such as the photosensitive drum 40 and is connected to the output shaft and the driven shaft such as a drum shaft 70, and the drive source. In each of the driving devices, each of the gears is configured such that a thrust moving force toward the driven body is generated in the sun gear such as the first sun gear 121 provided integrally with the carrier such as the first carrier 123. The torsional direction and the rotational direction of the toothed gear are set, and the thrust moving force is transmitted to a carrier such as the second carrier 133 disposed on the driven body side. An urging means for urging the last-stage carrier such as the two-carrier 133 toward the drive source side is provided.
According to this, as described in the above embodiment, the following drive device can be provided. The rotational speed fluctuation of the driven body such as the photosensitive drum 40 is reduced by suppressing the force that moves the carrier such as the first carrier 123 and the second carrier 133 of the planetary gear speed reduction device such as the planetary gear speed reduction device 120 in the thrust direction. It can be an inexpensive drive device such as the drum drive device 110.

(Aspect B)
In (Aspect A), the biasing means configured by the pressurizing spring 85, the spring receiver 84, and the like biases the final stage carrier such as the second carrier 133 toward the drive source such as the drive motor 111. The power of the last stage is made larger than the thrust moving force transmitted from a sun gear such as the second sun gear 131 provided integrally with the nearest carrier such as the first carrier 123. Is.
According to this, as described in the above embodiment, the carrier such as the first carrier 123 and the second carrier 133 of the planetary gear reduction device such as the planetary gear reduction device 120 is more effectively thrust than (Aspect A). The force to move in the direction can be suppressed. Further, it is possible to prevent the last stage carrier such as the second carrier 133 from moving and hitting a part of the casing such as the end cap 144 to deform the internal gear such as the internal gear 140.

(Aspect C)
In (Aspect A) or (Aspect B), the driven body such as the photosensitive drum 40 is configured to be detachable from an apparatus main body such as the copying machine main body 100 including the driving apparatus such as the drum driving apparatus 110. The biasing means including a pressure spring 85 and a spring receiver 84 biases the driven body mounted on the apparatus main body toward the drive source such as the drive motor 111 in the thrust direction. It is also used as a positioning means for positioning.
According to this, as described in the above embodiment, the driving device can be simplified and can be configured at a lower cost than the configuration in which the positioning unit and the biasing unit are separately provided.

(Aspect D)
In any one of (Aspect A) to (Aspect C), the driven body shaft such as the drum shaft 70 is connected to the front side plate 161 of the apparatus main body such as the copying machine main body 100 including the driving device such as the drum driving device 110. Positioning in the radial direction is performed via bearings such as the first drum bearing 81 and the third drum bearing 83 at two places such as the face plate 163 and the rear plate 164 to be fixed, and from the pressure spring 85 and the spring receiver 84 Movement of the last stage carrier such as the second carrier 133 in the thrust direction by the urging force of the urging means configured as described above causes the bearing such as one third drum bearing 83 in one of the two locations of the apparatus main body to move. It is characterized by being restricted by the apparatus main body.
According to this, as described in the above embodiment, the radial direction and the thrust direction with respect to the apparatus main body such as the copying machine main body 100 including the driving apparatus such as the drum driving apparatus 110 of the driven body such as the photosensitive drum 40 are provided. Positioning can be performed with high accuracy. Further, it is possible to reduce the frictional resistance at the location where the thrust drum is positioned such as the side surface of the third drum bearing 83 and the contact surface of the regulating plate 165.

(Aspect E)
In any one of (Aspect A) to (Aspect D), the driven body such as the photosensitive drum 40 provided in the apparatus main body such as the copying machine main body 100 including the driving apparatus such as the drum driving apparatus 110 is removed. By fixing a face plate such as a face plate 163 that supports one end side of the driven body shaft such as the drum shaft 70 to an opening such as a notch hole 162 used for drawing out, a pressure spring 85 and a spring receiver 84 are fixed. The biasing means configured to bias the final stage carrier such as the second carrier 133 toward the drive source side such as the drive motor 111 is generated by the biasing means including the above.
According to this, as described in the above embodiment, the work for exchanging the driven body such as the photosensitive drum 40 can be simplified and facilitated, and the convenience of the operator who replaces the driven body is improved. Can be made.

(Aspect F)
In an image forming apparatus such as a copying machine 500 including a plurality of driven bodies such as a photosensitive drum 40 that is rotationally driven and a third support roller 16 that is a driving roller of the intermediate transfer belt 10, A driving device such as the drum driving device 110 according to any one of (Aspect A) to (Aspect E) is provided as a driving device for a driven body such as at least one photosensitive drum 40. It is.
According to this, as described in the above embodiment, the following image forming apparatus such as the copying machine 500 can be provided. The effect similar to that of any one of the driving devices according to (Aspect A) to (Aspect E) is obtained by at least one of the plurality of driven members such as the photosensitive drum 40 and the third support roller 16. It can be performed by a driving device such as the drum driving device 110 of the driven body.

DESCRIPTION OF SYMBOLS 10 Intermediate transfer belt 14, 15, 16 Support roller 17 Intermediate transfer belt cleaning device 18 Image forming unit 18 Image forming unit 20 Tandem image forming unit 21 Exposure device 22 Secondary transfer device 23a, b Roller (secondary transfer device)
24 Secondary transfer belt 25 Fixing device 26 Fixing belt 27 Pressure roller 28 Sheet reversing device 30 Document table 32 Contact glass 33 First traveling body 34 Second traveling body 35 Imaging lens 36 Reading sensor 40 Photosensitive drum 42 Paper feed roller 43 Paper Bank 44 Paper Feed Cassette 45 Separating Roller 46 Paper Feeding Path 47 Conveying Roller 49 Registration Roller 50 Paper Feeding Roller 51 Manual Tray 52 Separating Roller 53 Manual Feeding Path 55 Switching Claw 56 Ejecting Roller 57 Paper Ejecting Tray 60 Photosensitive Drum Unit 61 Unit case 64 Front drum flange 65 Boss (front drum flange)
66 Rear drum flange 67 Rear drum flange 67 Female shape (serrated coupling)
70 Drum shaft 71 Male shape (serrated coupling)
72 Serration Coupling 85 Pressurizing Spring 100 Copier Main Body 110 Drum Drive Device 111 Drive Motor 112 Motor Shaft 113 Motor Fixing Flange 114 Internal Gear Fixing Flange 115 Hole (Internal Gear Fixing Flange)
116 drive side plate 120 planetary gear reduction device 121 first sun gear 122 first planetary gear 123 first carrier 124 first carrier pin 131 second sun gear 132 second planetary gear 133 second carrier 134 second carrier pin 136 protrusion 138 Output shaft 140 Internal gear 141 Tooth profile 142 Bearing surface (internal gear)
143 Boss (Internal gear)
144 End cap 145 Output shaft bearing 150 Stud 153, 154 Screw 161 Front side plate 162 Hole (front side plate)
162 Notch hole 163 Face plate (front plate)
164 Rear side plate 165 Restriction plate (rear side plate)
171 Joint 200 Paper feed table 300 Scanner 400 Automatic document feeder 500 Copying machine P Sheet

JP 2006-307909 A

Claims (6)

At least two stages of planetary gear mechanisms having a sun gear that is rotated by a rotational driving force transmitted from a drive source and an internal gear that is fixed in rotation are provided, and each gear is constituted by a helical gear. In a drive device comprising a planetary gear speed reduction device having an output shaft on a stage carrier, a driven body shaft supporting the driven body and connected to the output shaft, and the drive source,
A twisting direction and a rotating direction of each helical gear are set so that a thrust moving force toward the driven body is generated in the sun gear provided integrally with the carrier, and the thrust moving force is arranged on the driven body side. A drive device comprising a biasing means configured to be transmitted to the carrier and biasing the last stage carrier from the driven body shaft side toward the drive source side. The drive device according to claim 1,
The urging force for urging the last stage carrier toward the drive source side by the urging means is greater than the thrust moving force transmitted from a sun gear integrally provided on the nearest carrier. A drive device characterized by being enlarged. The drive device according to claim 1 or 2,
The driven body is configured to be attachable to and detachable from an apparatus main body including the driving device.
The driving device according to claim 1, wherein the biasing unit is also used as a positioning unit that biases the driven body attached to the apparatus main body toward the driving source to position in the thrust direction. In the drive device according to any one of claims 1 to 3,
The driven body shaft is positioned in the radial direction through a bearing at two locations of the apparatus body including the driving device,
The drive in the thrust direction of the last stage carrier due to the urging force of the urging means is regulated by the apparatus main body through one of the two bearings of the apparatus main body. . In the drive device according to any one of claims 1 to 4,
By fixing a face plate supporting one end side of the driven body shaft to an opening portion used when removing and pulling out the driven body provided in the apparatus main body provided with the driving apparatus, the biasing means 2. A driving device according to claim 1, wherein a biasing force for biasing the last stage carrier toward the driving source is generated. In an image forming apparatus including a plurality of driven bodies that are rotationally driven,
An image forming apparatus comprising: the driving device according to claim 1 as a driving device for at least one of the plurality of driven bodies.

Images