JP2013096476A - Planetary gear device, and image forming apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a planetary gear device capable of reducing rotation unevenness caused by a concentricity error between an internally toothed gear and a sun gear which is provided coaxially with a drive shaft and between the internally toothed gear and a carrier.SOLUTION: A drive motor 111 is positioned and fixed to a stud 150 which is supported by the body rear side plate 164 of a copier 500, and disposed coaxially with an internally toothed gear 140 and a first-stage sun gear 123 which is formed coaxially with the motor shaft 112 of a drive motor 111. A seat surface 142 is then provided at the output side of the internally toothed gear 140, and the seat surface 142 and the body rear side plate 164 of the copier 500 are positioned and fixed by screws. The side of the drive motor 111 in the internally toothed gear 140 is made into free end with no support structure.

Description

  The present invention relates to a planetary gear device that changes the rotational driving force of a drive source to a rotational speed required by a driving target and transmits the drive, and image formation such as a copying machine, a printer, and a facsimile machine equipped with the planetary gear device. It relates to the device.

  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. For example, the following configuration is known in an electrophotographic image forming apparatus. An electrostatic latent image is formed on the surface of a rotating cylindrical latent image carrier (hereinafter referred to as a photosensitive drum), and the developed electrostatic latent image is developed with toner attached thereto, and the developed toner image is endless. Primary transfer is performed on a belt-like image carrier (hereinafter referred to as an intermediate transfer belt). Further, the toner image primarily transferred onto the intermediate transfer belt is secondarily transferred onto a recording medium and fixed to obtain an image. As described above, the image forming apparatus includes many rotating bodies such as a photosensitive drum, a driving roller for driving an endless belt-like member such as an intermediate transfer belt and a transfer belt, a conveyance roller for conveying a recording medium and the like. Is used.

  As described above, in general, high accuracy is required to drive the rotating body used in the image forming apparatus. For example, when a speed fluctuation occurs in the surface moving speed of a photosensitive drum, an intermediate transfer belt, or the like, jitter and density unevenness occur on the output image. When the speed fluctuation continues at a frequency on the photosensitive drum or the intermediate transfer belt, periodic density unevenness occurs in the entire image, which is visually recognized as banding of a striped pattern. In addition, the speed fluctuation of the photosensitive drum may cause a sub-scanning position shift of the writing system exposure line or a sub-scanning position shift during the primary transfer of the toner image from the photosensitive drum to the intermediate transfer belt. To do. On the other hand, the speed fluctuation of the intermediate transfer belt causes a sub-scanning position shift between the primary transfer and the secondary transfer. Then, the image quality is remarkably deteriorated due to banding caused by the speed fluctuation.

  Since such high-accuracy driving is required, a mechanism for transmitting the rotational driving force from the driving source to the rotating body to be driven in a state where the rotational fluctuation is small is desired. Further, a plastic gear formed by injecting molten resin is often used for the drive transmission portion of the photosensitive drum and the intermediate transfer belt. Compared with metal gears, plastic gears have the advantages of having self-lubricating properties, low noise during use, light weight, high corrosion resistance, 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, it has been proposed to use a planetary gear mechanism so that sufficient durability can be obtained even when a plastic gear is used.

  Even when a plastic gear is used, sufficient durability can be obtained for the following reason. The planetary gear mechanism is disposed at equal intervals in the circumferential direction in the internal gear, a sun gear that rotates by receiving the rotational driving force of the drive source, an internal gear that is coaxially arranged with the sun gear, and the internal gear. And a plurality of planetary gears meshing with the sun gear and the internal gear. In addition, a planetary gear is rotatably supported by a carrier pin, and a carrier that is rotatable coaxially with the sun gear and the internal gear is also provided. Then, by rotating the sun gear by the rotational driving force from the drive source, a plurality of planetary gears revolve around the sun gear while rotating the carrier while rotating in the internal gear around the carrier pin as a support shaft. The rotational driving force generated by the rotation of the carrier is transmitted to the rotating body via an output shaft connected to the carrier and the rotating body. As described above, the rotational driving force from the driving source can be distributed and transmitted to a plurality of planetary gears, so that the rotational load generated when the rotational driving force is transmitted can also be distributed, and even when a plastic gear is used, sufficient durability can be achieved. It can be obtained.

  As a conventional planetary gear device using a plastic gear, for example, Patent Document 1 describes a planetary gear device (transmission mechanism unit for rotating equipment) having the following configuration in which one stage of a planetary gear mechanism is provided. ing. A sun gear of a planetary gear device is provided coaxially with an output shaft (hereinafter referred to as drive shaft) of a drive source, and a carrier is rotatably supported on the drive shaft. And the cylindrical housing which provided the internal gear of the planetary gear apparatus integrally is screwed and fixed to the supporting member of the apparatus main body to be used. The drive source (small DC motor) is fitted into a cylindrical housing, and is screwed to a partition perpendicular to the axial direction separating the planetary gear mechanism provided in the cylindrical housing and the drive source.

  However, in the configuration of Patent Document 1, as a hindrance to high-precision driving of a rotating body such as a photosensitive drum that is a transmission destination of the rotational driving force, there is a relationship between the rotating shaft that drives the rotating body and the output shaft of the planetary gear device. A concentric error at the connecting portion can be cited, which causes rotation unevenness of the rotating body (hereinafter simply referred to as rotation unevenness). Concentric errors include decentration, declination, and axial misalignment. In addition, concentric errors between the internal gear and the sun gear and between the internal gear and the carrier are also cited, which similarly causes rotation unevenness. Then, it is difficult to align the concentric errors between the internal gear and the sun gear and between the internal gear and the carrier for the following reason.

  Since the drive source is fitted into the cylindrical housing and screwed to the partition wall of the cylindrical housing, even if a concentric error occurs between the drive source and the drive shaft, the drive source is decentered and declinated with respect to the cylindrical housing. It is difficult to adjust the position of the driving source, such as the separation distance. For this reason, it becomes difficult to align the concentric error between the internal gear and the drive shaft, that is, the internal gear and the sun gear provided coaxially with the drive shaft. For the same reason, it is difficult to align the concentric error between the internal gear and the carrier supported rotatably on the drive shaft. Since alignment of these concentric errors is difficult, in the configuration of Patent Document 1, the rotation is caused by the concentric error between the internal gear and the sun gear provided coaxially with the drive shaft, and the internal gear and the carrier. Unevenness is inevitable. Also, in a multi-stage planetary gear device that fixes a drive source to a cylindrical housing integrated with an internal gear, similarly to Patent Document 1, an internal gear and a first-stage sun gear, and an internal gear and a carrier Rotation unevenness due to the concentric error is inevitable.

  The present invention has been made in view of the above problems, and an object thereof is to provide the following planetary gear device. This is a planetary gear device that can reduce uneven rotation caused by a concentric error between the internal gear and the carrier, and a sun gear provided coaxially with the internal gear and the drive shaft.

In order to achieve the above object, an invention according to claim 1 is directed to a sun gear that rotates by receiving a rotational driving force from a drive source, an internal gear disposed coaxially with the sun gear, A plurality of planetary gears arranged at equal intervals in the circumferential direction in the internal gear and meshing with the sun gear and the internal gear, and rotatably supporting the planetary gear, the sun gear and the inner gear In a planetary gear device in which one or more planetary gear mechanisms composed of a toothed gear and a coaxially rotatable carrier are provided, and the output unit is integrally provided in the final carrier, the drive source is the device used Positioned and fixed to a holding member supported by a main body side plate, and arranged coaxially with the internal gear and the sun gear that rotates by receiving a rotational driving force from the drive source, the output portion of the internal gear The side is positioned and fixed to the main body side plate, Driving source side of the serial internal gear is characterized in that a free end without the support structure.
In the present invention, since the drive source side of the internal gear is a free end, the internal gear can be made with appropriate rigidity and the internal gear can be deformed. Therefore, by deforming the internal gear, the output shaft of the internal gear and the drive source, that is, the sun gear provided coaxially between the internal gear and the drive shaft, and the concentric error between the internal gear and the carrier are aligned. can do.

In the present invention, by deforming the internal gear, a concentric error between the internal gear and the sun gear provided coaxially with the drive shaft and the internal gear and the carrier can be aligned.
Therefore, it is possible to provide a sun gear provided coaxially with the internal gear and the drive shaft, and a planetary gear device that can reduce rotation unevenness due to a concentric error between the internal gear and the carrier.

1 is a schematic configuration diagram of a copier according to an embodiment. FIG. 3 is an explanatory diagram of a drum driving device according to the first embodiment. Explanatory drawing of the drum drive device which concerns on the present Example 2. FIG. Explanatory drawing of the drum drive device which concerns on this Example 3. FIG. Explanatory drawing of the drum drive device which concerns on this Example 4. FIG. Explanatory drawing of the joint of a clearance fit system of a photoconductor drum axis | shaft and an output shaft. Explanatory drawing of the friction type joint of a photosensitive drum axis | shaft and an output shaft.

  Hereinafter, an embodiment in which the present invention is applied to an electrophotographic color copying machine (hereinafter referred to as a copying machine 500) as an image forming apparatus will be described with reference to the drawings. First, an outline of the copier 500 of the present embodiment common to the respective examples will be described. Here, FIG. 1 is a schematic configuration diagram of a copying machine 500 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). The copying machine 500 is a tandem type electrophotographic copying machine that employs an intermediate transfer (indirect transfer) method.

  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 recording medium 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. Further, in the present embodiment, a recording that reverses the sheet P to record images on both sides of the sheet P in parallel with the tandem image forming unit 20 described above under the secondary transfer device 22 and the fixing device 25 described above. A media reversing device 28 is also provided.

  When making a copy 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 by it. 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 first 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 rotated for the corresponding photosensitive drums (not shown). It is rotated by the drum driving device 110Y, M, C, K which is a driving 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 photosensitive drums 40Y, 40M, 40C, and 40K are sequentially transferred so as to overlap each other on the intermediate transfer belt 10, 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 is put into the recording medium reversing device 28, where it is reversed and guided again to the transfer position, and an 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. Discharge.

  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. 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 characteristic portions of the present embodiment. , K will be described with reference to a plurality of examples. 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. Moreover, the same code | symbol is used about the same member.

Example 1
First, an explanation will be given from Example 1 as a first example of the present embodiment with reference to the drawings. FIG. 2 is an explanatory diagram of the drum driving device 110 according to the present embodiment.
As shown in FIG. 2, the planetary gear reduction device 120 of the present embodiment used in the drum drive device 110 uses a 2KH type two-stage planetary gear mechanism.

  A first-stage sun gear 121 that is an input shaft of the first-stage planetary gear mechanism in the planetary gear reduction device 120 is coaxially and integrally formed with a motor shaft 112 that is a drive shaft of the drive motor 111 that is a drive source. Is formed. The first stage planetary gear 122 that meshes with the first stage sun gear 121 and the tooth profile 141 of the internal gear 140 is rotatably supported by the first stage carrier 123, and the first stage sun gear 121. It is designed to revolve around the circumference of the. The first stage planetary gear 122 is concentrically arranged at three or more positions for rotational balance and torque sharing. In the present embodiment, the first stage planetary gear 122 is arranged at a position divided into three equal parts in the circumferential direction. The first-stage planetary gear 122 rotates and revolves by meshing between the first-stage sun gear 121 and the tooth profile 141 of the internal gear 140. The first-stage carrier 123 that supports the first-stage planetary gear 122 is decelerated with respect to the rotation of the first-stage sun gear, and the first-stage reduction ratio is obtained. Further, the second stage sun gear 131 provided at the rotation center of the first stage carrier 123 serves as an input to the second stage planetary gear mechanism. This first stage carrier 123 does not have a rotation support portion, and performs floating rotation.

  Similarly, the second stage planetary gear 132 that meshes with the second stage sun gear 131 and the tooth profile 141 of the internal gear 140 that is integrally formed up to the second stage is rotatably supported by the second stage carrier 133. The outer periphery of the sun gear 131 at the second stage is revolved. In the present embodiment, the second stage planetary gears 132 are arranged at positions that are equally divided into four in the circumferential direction. That is, four second-stage planetary gears 132 are arranged on the second-stage carrier 133. Here, the second-stage carrier 133 corresponding to the final stage includes a cylindrical portion 136 that is an output portion of the planetary gear reduction device 120 and a spline joint portion of the drum shaft 70 on the planetary gear reduction device 120 side. Is provided. An inner toothed portion 137 that forms a female spline joint is formed coaxially with the second-stage carrier 133 on the inner peripheral surface of the cylindrically shaped portion 136. The second stage carrier 133 does not have a rotation support portion, and performs floating rotation. On the other hand, on the photosensitive drum unit 60 side that holds the photosensitive drum 40, the spline joint on the photosensitive drum unit 60 side is engaged with the drum shaft 70 that is the rotating shaft of the photosensitive drum 40 so as to mesh with the above-described internal tooth shape portion 137. The external-tooth shape part 72 used as a part is formed. This external tooth shape portion 72 becomes an input portion of the photosensitive drum unit 60. The first-stage sun gear 121, the internal gear 141 and each carrier are arranged so as to be coaxial.

  Here, the configuration of the 2KH type planetary gear mechanism used in the planetary gear reduction device 120 of the present embodiment and the operating principle thereof will be described. One unit used in the 2KH type planetary gear mechanism includes a sun gear, a planetary gear, a planetary carrier that supports the revolving motion of the planetary gear, and an outer gear. It consists of four parts. Of the three elements that are 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 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, each of which is one element out of three elements. This is a mechanism that couples each other, fixes the remaining one by one, and uses the remaining two as an input shaft or output shaft.

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)

  Here, the material of the main components of the planetary gear mechanism used in the planetary gear reduction device 120 of the present embodiment will be described. The internal gear 140, the first stage planetary gear 122, the second stage planetary gear 132, the first stage carrier 123, and the second stage sun gear 131 integrated with the first stage carrier 123 are made of resin. ing. The second-stage carrier 133 and the cylindrical portion 136 integrated with the second-stage carrier 133 are also made of resin. On the other hand, the first-stage sun gear 121, the first-stage carrier pin 124, and the second-stage carrier pin 134 are made of metal.

  Next, the support structure of the internal gear 140 and the drive motor 111 will be described. First, the support of the internal gear 140 will be described. The internal gear 140 has a tooth profile portion 141 formed with a coaxial internal tooth shape, and a seat surface 142 extending in the inner diameter direction of the internal gear 141 on the output side, around the center of the seat surface 142. Is provided with a hole having a boss portion 143. In the internal gear 140, the boss portion 143 is fitted into a hole 165 provided in the main body rear side plate 164, and is fixed to the main body rear side plate 164 with a seating surface 142. Thus, the positioning and fixing of the internal gear 140 and the main body rear side plate 164 can be simplified by fitting the boss portion 143 of the seating surface 142 of the internal gear 140 and the hole 165 provided in the main body rear side plate 164. Can be reliably performed with a simple configuration.

  In addition, the drum shaft 70 is rotatably supported in a hole inside the boss portion 143 via a bearing 84. Thus, the internal gear 140 is positioned directly on the main body rear side plate 164 to ensure the concentric accuracy of the drum shaft 70 with respect to the internal gear 140.

  On the other hand, in the drive motor 111 on the input side, a motor flange 114 joined via a motor drive circuit board 113 is screwed to the drive side plate 116. The motor flange 114 has a circular boss portion 115 and is fitted into a hole 117 provided in the driving side plate 116 to be positioned. The drive side plate 116 is fixed to a stud 150 that is a holding member that is crimped to the main body rear side plate 164. The stud 150 and the driving side plate 116 are fitted and positioned with a stepped portion at the tip of the stud 150. With the above configuration, the concentric error between the internal gear 140 and the drive gear 111 and the sun gear 121 directly cut on the motor shaft 112 of the drive motor 111 is minimized.

  The positional relationship between the internal gear 140 and the drive motor 111 will be described. The drive gear 111 side of the internal gear 140 is a circular full surface opening where the tooth profile 141 is not formed. A boss portion 115 of the motor flange 114 enters the inner peripheral surface with a spigot. However, a gap is provided between the inner peripheral surface of the internal gear 140 on the drive motor 111 side and the boss portion 115 of the motor flange 114, and the internal gear 140 is not supported by the boss portion 115 but becomes a free end. Yes. A gap is also provided between the drive source side end of the internal gear 140 on the drive motor 111 side and the drive side plate 116. In this way, the drive motor 111 side of the internal gear 140 is a free end. As described above, the internal gear 140 is molded from resin. By making the drive motor 111 side of the internal gear 140 such a free end, the internal gear 140 is deformed when a concentric error occurs between the internal gear 140 and the first-stage sun gear 121. Can do. The internal gear 140 can also be deformed when a concentric error occurs between the internal gear 140 and the first stage carrier 123 and / or the second stage carrier 133.

  By appropriately setting the rigidity of the internal gear 140, the internal gear 140 is deformed according to the concentric error between the internal gear 140 and each carrier, and between the internal gear 141 and the first-stage sun gear. Can be made. Therefore, the concentric error between the internal gear 140 and each carrier and the internal gear 140 and the first-stage sun gear can be aligned by this deformation. Therefore, the internal gear 140 is deformed, and the rotation unevenness due to the concentric error between the internal gear 140 and each carrier, and the internal gear 140 and the motor shaft 112 of the drive motor 111, that is, the first stage sun gear 121. It is possible to provide the planetary gear reduction device 120 that can reduce the above.

  Further, in this embodiment, as described above, each carrier constituted by two stages is supported in a floating manner, and rotation unevenness due to concentric errors between the first stage sun gear 121, the internal gear 140, and each carrier, It can be reduced by the aligning action by the floating support of each carrier. Here, in this embodiment, each of the two-stage carriers is configured to support floating. However, the present invention is not limited to such a configuration, and can be applied to a configuration in which at least one of a plurality of carriers configured to float is supported with respect to the internal gear 140. By supporting at least one or more of the carriers composed of a plurality of stages with respect to the internal gear 140, the first-stage sun gear 121 and / or the internal gear 140 and the carrier that is floatingly supported. Uneven rotation due to concentric errors can be reduced.

  In general, in the planetary gear reduction device, the load on the input side of the internal gear is smaller than that on the output side. In the planetary gear reduction device 120 of the present embodiment, since the side where the load of the internal gear 140 is small is the free end, the side where the load of the internal gear 140 is large, that is, the output side is slightly free. It has an advantageous structure in terms of durability.

  In addition, a clearance between the drive source side end of the internal gear 140 and the drive side plate 116 facing the drive source side end is formed on the outer periphery of the drive source side end of the internal gear 140 on a resin or rubber system. A sheet 145 which is a flexible member is provided and sealed. By sealing the gap between the drive source side end portion of the internal gear 140 and the member facing the drive source side end portion in this way, it is possible to prevent foreign matter and dust from entering from the gap. Here, as the sheet 145, a resin-based fluororesin, a polyethylene resin, a rubber-based urethane rubber sheet, a silicon rubber sheet, a urethane rubber sponge, a silicon rubber sponge, or the like can be used.

  Further, as described above, the present invention is not limited to the drum driving device 110 of the photosensitive drum that is a latent image carrier. For example, the third support roller that is a driving roller that rotationally drives the intermediate transfer belt 10. The present invention can also be applied to 16 rotational drive devices. In particular, by applying the present invention to the rotational driving device of the photosensitive drum and the intermediate transfer belt 10, it is possible to suppress deterioration in image quality due to banding or the like due to jitter, density unevenness, and sub-scanning position deviation.

  Next, the support mechanism for the photosensitive drum 40 will be described. First, the configuration of the photosensitive drum unit 60 will be described. A rear drum flange 66 on the drive motor 111 side and a front drum flange 64 on the opposite side are fixed to the end of the photosensitive drum 40 in the axial direction, and each drum flange is supported by the drum shaft 70. The rear drum flange 66 is connected to the drum shaft 70 by a serration coupling, and when the drum shaft 70 rotates, the photosensitive drum 40 rotates synchronously. The serration coupling is provided with a male-shaped portion 71 on the drum shaft 70 side and a female-shaped portion 67 on the rear drum flange 66 side, and is tapered from the front side of the drum shaft 70.

  In the unit case 61 that supports the photosensitive drum 40, the photosensitive drum 40, the charging device 2, the developing device 9, the cleaning device 4, a static elimination lamp (not shown), and the like are accommodated. The rear side plate 63 of the unit case 61 is supported by a bearing 83 fixed to the drum shaft 70, and the rear drum flange 66 is also supported by the bearing 83, so that the photosensitive drum 40 and the unit case 61 are positioned. Yes. On the front side, the boss portion 65 of the front drum flange 64 is fitted with the front side plate 62 of the unit case so as to be rotatable.

  The drum shaft 70 is further provided with another bearing 84 on a portion of the seating surface 142 of the internal gear 140 that is fitted to the main body rear side plate 164 and fitted to the inner surface of the boss portion 143. The main body rear side plate 164 is positioned. The main body front plate 161 is provided with a notch 162 for attaching / detaching the photosensitive drum unit 60, and a face plate 163 is fixed thereto. A front end portion of the drum shaft 70 is rotatably supported by the face plate 163 via a bearing 81. The photosensitive drum unit 60 can be attached and detached by removing the face plate 163. When the photosensitive drum unit 60 is mounted, the photosensitive drum 40 is moved in the drum axial direction by the pressure spring 82 provided between the bearing 81 fixed to the face plate 163 and the boss portion 65 of the front drum flange 64. Pressurized. Then, the rotational direction and the thrust direction are positioned by the tapered serration coupling portion.

(Example 2)
Next, Example 2 which is a second example of the present embodiment will be described with reference to the drawings. FIG. 3 is an explanatory diagram of the drum driving device 110 according to the present embodiment. Here, the present embodiment is different from the above-described first embodiment only in the drum driving device 110 relating to the fixing of the internal gear 140 of the planetary gear reduction device 120 to the main body rear side plate 164. Other configurations are the same as those of the first embodiment described above, and therefore similar configurations will be omitted as appropriate.

  As shown in FIG. 3, in this embodiment, a speed reducer side plate 151, which is a transmission side plate, is provided between the output side seating surface 142 of the internal gear 140 and the main body rear side plate 164. The rear plate 164 of the main body is provided with holes 152 that are fitted to the boss portions 143 provided on the seating surface 142 of the internal gear 140 and positioned relative to each other. When assembling, the boss portion 143 and the hole 152 are fitted to each other and the planetary gear supported by each carrier is assembled in the internal gear 140 of the planetary gear speed reduction device 120 to reduce the speed. Screwed to the machine side plate 151. Here, the boss portion 143 of the seat surface 142 is formed so as to protrude from the main body rear side plate 164 in a state where the boss portion 143 is fixed to the speed reducer side plate 151 with screws. Then, after the internal gear 140 is screwed to the speed reducer side plate 151, the boss portion 143 of the seating surface 142 and the hole 165 provided in the main body rear side plate 164 are fitted, positioned, and screwed. It becomes. That is, the internal gear 140 is fixed to the main body rear side plate 164 via the reduction gear side plate 151 with screws. In this way, the internal gear 140 is screwed to the main body rear plate 164 via the speed reducer side plate 151, so that the planetary gear speed reduction device 120, which is a transmission, is assembled as a module, and then the main body rear plate of the copying machine 500 to be used 164 can be fixed. Therefore, the assemblability of the planetary gear reduction device 120 is improved.

  Further, a stud 150 that is a holding member that holds the drive motor 111 via the drive side plate 116 is caulked and positioned and fixed to the speed reducer side plate 151. Since the stud 150 is positioned and fixed to the speed reducer side plate 151 in this way, the planetary gear speed reduction device 120 and the drive motor 111 can be fixed to the main body rear side plate 164 of the copying machine 500 to be used after the module is assembled. Easy to assemble and handle. Here, the fixing of the driving side plate 116 and the fixing of the driving motor 111 are the same as those in the first embodiment described with reference to FIG.

(Example 3)
Next, Example 3 which is a third example of the present embodiment will be described with reference to the drawings. FIG. 4 is an explanatory diagram of the drum driving device 110 according to the present embodiment. Here, the present embodiment is different from the above-described second embodiment only in the point relating to the output unit of the planetary gear reduction device 120 in the drum driving device 110. The other configuration is the same as that of the above-described second embodiment, and therefore the same configuration will be omitted as appropriate.

  As shown in FIG. 4, in the present embodiment, unlike the second embodiment in which the cylindrical portion 136 is provided in the second-stage carrier 133 as the output section of the planetary gear reduction device 120, the second-stage carrier 133 is provided with the second-stage carrier 133. An output shaft 138 is provided. The output shaft 138 and the drum shaft 70 provided on the second-stage carrier 133 are integrally formed. Here, the drum shaft 70 (output shaft 138) and the second-stage carrier 133 are made of metal, and are integrated by caulking or press-fitting the drum shaft 70 into the second-stage carrier 133. The drum shaft 70 that also serves as the output shaft 138 of the planetary gear reduction device 120 is coaxially disposed in the hole of the boss portion 143 provided on the seating surface 142 of the internal gear 140 via the bearing 84.

  As described above, the output shaft 138 of the planetary gear reduction device 120 and the drum shaft 70 are integrally formed, so that the concentric error between the output portion of the planetary gear reduction device 120 and the output shaft 138 of the photosensitive drum 40 can be eliminated. The concentric accuracy can be improved. Here, the second-stage carrier 133 is supported by the bearing 84 via the drum shaft 70 (output shaft 138), and is not floating support. However, since the first stage carrier 123 is supported in a floating manner, rotation unevenness due to the concentric error between the first stage sun gear 121 and / or the internal gear 140 and the carrier 123 can be reduced.

Example 4
Next, Example 4 which is the 4th example of this embodiment is explained using a figure. FIG. 5 is an explanatory diagram of the drum driving device 110 according to the present embodiment. FIG. 6 is an explanatory view of a clearance fit type joint 171 between the drum shaft 70 and the output shaft 138, and FIG. 7 is an explanatory view of a friction type joint 172 between the drum shaft 70 and the output shaft 138. is there. Here, in the present embodiment and the above-described third embodiment, in the drum driving device 110 of the present embodiment, the output shaft 138 of the planetary gear reduction device 120 and the drum shaft 70 of the photosensitive drum 40 are connected using a connecting member. The only difference is that they are consolidated. Other configurations are the same as those in the third embodiment described above, and thus similar configurations will be omitted as appropriate.

  As shown in FIG. 5, in this embodiment, an output shaft 138 is integrally provided at the rotation center of the second stage carrier 133 corresponding to the final stage, and a joint member which is a connecting member on the hollow cylinder is provided. It is connected to the drum shaft 70 via the via. The output shaft 138 and the second-stage carrier 133 are integrated in the same manner as in the third embodiment described with reference to FIG. However, the output shaft 138 and the drum shaft 70 are separate, and a bearing 84 provided on the boss 143 of the internal gear 140 and a bearing 83 that is fixed to the drum shaft 70 and supports the rear side plate 63 of the unit case 61. It is connected with the joint provided between.

  As for the structure of the joint, the structure shown in FIGS. The joint 171 shown in FIG. 6 includes a hollow cylindrical member 173 and a stepped screw 174. The drum shaft 70 and the output shaft 138 of the planetary gear reduction device 120 have the same diameter, the hollow cylindrical member 173 is press-fitted into the drum shaft 70, and the output shaft 138 has a clearance fit. The hollow cylindrical member 173 and the stepped screw 174 are connected and fixed.

  On the other hand, the joint 172 shown in FIG. 7 includes a hollow cylindrical member 175 and a screw 176. The hollow cylindrical member 175 has a slit 177 in the center from the output shaft 138 side, and the output shaft 138 is connected and fixed by a frictional force with the hollow cylindrical member 175 pushed and bent by the screw 176. It is the composition which becomes. In either configuration, the shift of the central axis between the drum shaft 70 and the output shaft 138 due to the joint member is minimized, and the drive can be transmitted.

  As described above, the drum shaft 70 of the photosensitive drum 40 and the output shaft 138 of the planetary gear reduction device 120 are configured separately and connected by the joint member, so that the concentric accuracy is improved and the planetary gear reduction device 120 and the drum are improved. The shaft 70 can be divided. Therefore, the assembling property and handling property of the drum driving device 110 can be improved.

  Further, in each of the above-described embodiments, the example in which the present invention is applied to the planetary gear reduction device 120 having a two-stage configuration has been described. However, the present invention is not limited to such a configuration, and three or more stages are configured. The present invention can also be applied to a planetary gear device having a single-stage configuration. However, as in the configurations described in the third and fourth embodiments, in a planetary gear device having a one-stage configuration in which the output shaft connected to the last stage carrier is supported by a bearing, the last stage carrier is floated. I can't support it.

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-stage sun gear 121 that rotates in response to a rotational driving force from a drive source such as a drive motor 111, and an internal gear such as an internal gear 140 disposed coaxially with the sun gear. A plurality of planets such as a first-stage planetary gear 122 and a second-stage planetary gear 132 that are disposed in the internal gear at equal intervals in the circumferential direction and mesh with the sun gear and the internal gear. A gear and a carrier such as a first-stage carrier 123 or a second-stage carrier 133 that rotatably supports the planetary gear and is coaxially rotatable with the sun gear or the internal gear. In a planetary gear device such as a planetary gear reduction device 120 in which one or more planetary gear mechanisms are provided, and an output portion such as a cylindrical portion 136 is integrally provided on a final stage carrier such as a second-stage carrier 133. The source is the copier 50 The sun gear that is positioned and fixed to a holding member such as a stud 150 supported by a main body side plate such as the main body rear side plate 164 of the device to be used, and that rotates by receiving a rotational driving force from the internal gear and the driving source. The internal gear is positioned and fixed to the main body side plate, and the drive source side of the internal gear is a free end without a support structure. .
According to this, as described in the first embodiment, the internal gear such as the internal gear 140 is deformed so that the internal gear and the drive shaft such as the motor shaft 112 of the drive source such as the drive motor 111 are coaxial. The concentric error between the sun gear such as the first-stage sun gear 121 and the internal gear and the carrier such as the first-stage carrier 123 and the second-stage carrier 133 can be aligned. Therefore, it is possible to provide a planetary gear device such as the sun gear provided coaxially with the internal gear and the drive shaft, and the planetary gear reduction device 120 that can reduce rotation unevenness caused by the concentric error between the internal gear and the carrier.
(Aspect B)
In (Aspect A), a drive source side end portion on the drive source side such as the drive motor 111 of the internal gear such as the internal gear 140 and a member such as the drive side plate 116 facing the drive source side end portion. The gap is sealed with a flexible member such as a resin-based or rubber-based sheet 145.
According to this, as described in the first embodiment, from the gap between the drive source side end of the internal gear such as the internal gear 140 and the member such as the drive side plate 116 facing the drive source side end. Can prevent foreign matter and dust from entering.
(Aspect C)
In (Aspect A) or (Aspect B), a plurality of planetary gear mechanisms are provided, and at least one of the carriers such as a plurality of first-stage carriers 123 and second-stage carriers 133 is an internal gear 140. The internal gear is configured to be supported in a floating manner.
According to this, as described in the first embodiment, the sun gear such as the first-stage sun gear 121 provided on the same axis, the internal gear such as the internal gear 140, and the first-stage carriers 123 and 2 are provided. Rotational unevenness due to a concentric error with the carrier such as the carrier 133 at the stage can be reduced by the aligning action by floatingly supporting the carrier.
(Aspect D)
In any one of (Aspect A) to (Aspect C), the internal gear such as the internal gear 140 has a seating surface such as a seating surface 142 on the main body side plate side such as the main body rear side plate 164, and the seat The surface and the main body side plate are formed with fitting portions such as a boss portion 143 and a hole 165 that can be positioned relative to each other, and positioning and fixing of the internal gear to the main body side plate is performed by the boss portion 143 or the like. The fitting portion of the seating surface is fitted and fixed to the fitting portion of the main body side plate such as the hole 165.
According to this, as described in the first embodiment, the positioning and fixing of the internal gear such as the internal gear 140 and the main body side plate such as the main body rear side plate 164 can be reliably performed with a simple configuration.
(Aspect E)
In any one of (Aspect A) to (Aspect D), a transmission side plate such as a speed reducer side plate 151 is provided on the main body side plate side such as the main body rear side plate 164 of the internal gear such as the internal gear 140. The positioning and fixing of the internal gear to the main body side plate is characterized in that, after the internal gear is fixedly supported on the transmission side plate, the transmission side plate is fixed to the main body side plate. .
According to this, as described in the second embodiment, since a planetary gear device such as the planetary gear reduction device 120 is assembled into a module and then fixed to a main body used for the copying machine 500 or the like, the assemblability is improved.
(Aspect F)
(Embodiment E) is characterized in that the holding member such as the stud 150 that positions and fixes the drive source such as the drive motor 111 is fixed to the transmission side plate such as the speed reducer side plate 151. .
According to this, as described in the second embodiment, after the planetary gear device such as the planetary gear reduction device 120 and the drive source such as the drive motor 111 are assembled in a module, it can be fixed to the main body used for the copying machine 500 or the like. Therefore, the assemblability and handling are improved.
(Aspect G)
In any one of (Aspect A) to (Aspect F), the final stage carrier such as the second stage carrier 133, the output section such as the output shaft 138, and the photosensitive drum 40 connected to the output section, etc. A rotating shaft such as the drum shaft 70 of the rotating body is integrally formed.
According to this, as described in the third embodiment, the output unit such as the output shaft 138 of the planetary gear device such as the planetary gear reduction device 120 and the rotation shaft such as the drum shaft 70 of the rotating body such as the photosensitive drum 40, and the like. Can be eliminated, and the concentric accuracy can be improved.
(Aspect H)
In (Aspect G), an output shaft such as an output shaft 138 is provided as the output unit, and the output shaft and a rotation shaft such as the drum shaft 70 of the rotating body such as the photosensitive drum 40 are connected to each other by a joint 171 or a joint 172. It is characterized by being connected by a member.
According to this, as described in the fourth embodiment, it is possible to divide the planetary gear device such as the planetary gear reduction device 120 and the rotating body shaft such as the drum shaft 70 while improving the concentric accuracy. Good sex.
(Aspect I)
In an image forming apparatus such as a copying machine 500 that includes a plurality of rotating bodies such as the photosensitive drum 40 and forms an image on a recording medium such as a sheet P, the rotation driving of any of the plurality of rotating bodies is performed. As a planetary gear device such as the planetary gear reduction device 120 used in the above, the planetary gear device of any one of (Aspect A) to (Aspect H) is provided.
According to this, as described in the above embodiment, an image forming apparatus such as a copying machine 500 including a planetary gear device such as a planetary gear reduction device 120 that can achieve the same effects as any of the aspects is provided. it can.
(Aspect J)
(Aspect I) In the planetary gear reduction device 120 such as the planetary gear reduction device 120, the rotating body used for rotational driving thereof is a latent image carrier such as the photosensitive drum 40 or an endless belt such as the intermediate transfer belt 10. The image bearing member is a driving roller such as a third support roller 16 for rotationally driving the image bearing member.
According to this, as described in the above embodiment, the latent image carrier such as the photosensitive drum 40 and the third support roller 16 that rotationally drives the endless belt-like image carrier such as the intermediate transfer belt 10 are provided. The speed fluctuation of the surface moving speed of the driving roller can be suppressed. Therefore, it is possible to suppress deterioration in image quality due to banding or the like due to jitter, density unevenness, and sub-scanning position deviation.

2 Charging device 4 Cleaning device 9 Developing device 10 Intermediate transfer belt 14 First support roller 15 Second support roller 16 Third support roller (drive roller)
17 Intermediate transfer belt cleaning device 18 Image forming unit 20 Tandem image forming unit 21 Exposure device 22 Secondary transfer device 23a, 23b Roller 24 Secondary transfer belt 25 Fixing device 26 Fixing belt 27 Pressure roller 28 Recording medium 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 feed path 47 Transport roller 49 Registration roller 50 Paper feed Roller 51 Tray 52 Separating roller 53 Paper feed path 55 Switching claw 56 Discharging roller 57 Discharging tray 60 Photosensitive drum unit 61 Unit case 62 Front side plate 63 Rear side plate 64 Front drum flange 65 Boss (front drum flange)
66 Rear drum flange 67 Female shape portion 70 Drum shaft 71 Male shape portion 72 External tooth shape portion 82 Pressure spring 100 Copier main body 110 Drum drive device 111 Drive motor 112 Motor shaft 113 Motor drive circuit board 114 Motor flange 115 Boss portion ( Motor flange)
116 drive side plate 117 hole (drive side plate)
120 planetary gear reduction device 121 first stage sun gear 122 first stage planetary gear 123 first stage carrier 124 first stage carrier pin 131 second stage sun gear 132 second stage planetary gear 133 second stage Carrier 134 Second stage carrier pin 136 Cylindrical part (output part)
137 Internal tooth shape part (output part)
138 Output shaft (output unit)
140 Internal gear 141 Tooth profile 142 Bearing surface (Internal gear)
143 Boss (Internal gear)
145 sheet (for sealing)
150 Stud 151 Reducer side plate 152 Hole (Reducer side plate)
161 Main body front plate 162 Hole (main body front plate)
163 Face plate (front plate)
164 Body rear side plate 165 Hole (Main body rear side plate)
171 and 172 Joints 173 and 175 Hollow cylindrical member 174 Stepped screw 176 Screw 177 Slit 200 Paper feed table 300 Scanner 400 Automatic document feeder 500 Copying machine P Sheet (recording medium)

Japanese Patent No. 3411996

Claims (10)

A sun gear that rotates by receiving a rotational driving force from a drive source, an internal gear that is coaxially arranged with the sun gear, and is arranged in the internal gear at equal intervals in the circumferential direction; A planetary gear comprising a plurality of planetary gears meshed with the sun gear and the internal gear, and a carrier that rotatably supports the planetary gear and is coaxially rotatable with the sun gear and the internal gear. In a planetary gear device in which one or more mechanisms are provided, and the output unit is integrated with the carrier of the final stage,
The drive source is positioned and fixed to a holding member supported by a main body side plate of the apparatus to be used, and is arranged coaxially with the internal gear and the sun gear that rotates by receiving a rotational drive force from the drive source,
The planetary gear device characterized in that the output side of the internal gear is positioned and fixed to the main body side plate, and the drive source side of the internal gear is a free end without a support structure. The planetary gear set according to claim 1,
A planetary characterized in that a gap between a drive source side end of the internal gear on the drive source side and a member facing the drive source side end is sealed with a resin-based or rubber-based flexible member Gear device. The planetary gear set according to claim 1 or 2,
It has a multi-stage planetary gear mechanism,
A planetary gear device, wherein at least one of the plurality of carriers is floatingly supported with respect to the internal gear. In the planetary gear device according to any one of claims 1 to 3,
The internal gear has a seating surface on the main body side plate side,
The seating surface and the main body side plate are formed with fitting portions that can be positioned relative to each other,
Positioning and fixing of the internal gear to the main body side plate is performed by fitting and fixing the fitting portion of the seating surface with the fitting portion of the main body side plate. The planetary gear device according to any one of claims 1 to 4,
A transmission side plate is provided on the main body side plate side of the internal gear,
The positioning and fixing of the internal gear to the main body side plate is performed by fixing and supporting the internal gear to the transmission side plate, and then fixing the transmission side plate to the main body side plate. The planetary gear set according to claim 5,
A planetary gear device, wherein the holding member for positioning and fixing the drive source is fixed to the transmission side plate. The planetary gear set according to any one of claims 1 to 6,
The planetary gear device, wherein the last stage carrier, the output unit, and a rotating shaft of a rotating body connected to the output unit are integrally formed. The planetary gear set according to claim 7,
An output shaft is provided as the output unit,
A planetary gear device, wherein the output shaft and the rotating shaft of the rotating body are connected by a connecting member. In an image forming apparatus that includes a plurality of rotating bodies and forms an image on a recording medium,
An image forming apparatus comprising the planetary gear device according to any one of claims 1 to 8 as a planetary gear device used for rotationally driving any one of the plurality of rotating members. The image forming apparatus according to claim 9.
The rotating body that uses the planetary gear device for rotation driving thereof,
An image forming apparatus comprising: a driving roller that rotationally drives a latent image carrier or an endless belt-like image carrier.

Images