JP5282611B2 - Rotating body driving device and image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a rotary driving device that reduces inclinations of planetary gears and a carrier supporting them, and to provide an image forming apparatus. <P>SOLUTION: The rotary driving device drives an image carrier drum 1 via a planetary differential gear reduction mechanism that includes: a sun gear 22 supported and driven by a body side plate 14; the plurality of planetary gears 23 engaged with the sun gear 22; the carrier 25 supporting the planetary gears 23 so that they may be freely rotated around themselves and also freely revolved around the sun gear 22; and a fixed inner gear 27 and movable inner gear 30 engaged with the planetary gears 23. A gear bearing 31 supporting the planetary gears' freely rotating around themselves and revolving around the sun gear is disposed between the engaging portions 23A and 23B of the planetary gears 23, which are engaged with the fixed inner gear 27 and movable inner gear 30 respectively. <P>COPYRIGHT: (C)2010,JPO&amp;INPIT

Description

  The present invention relates to a rotating body driving device that drives a rotating body such as an image carrier and an image forming apparatus using the rotating body driving device.

  In an image forming apparatus such as a copying machine, a printer, a facsimile, or a multifunction machine having at least two functions thereof, for example, a drum-shaped photoconductor is used as an image carrier. In this type of image forming apparatus, it is desired that the driving device for driving the photosensitive drum be provided with a reduction gear that is small and light and capable of transmitting a high reduction ratio and a large torque.

  Conventionally, a planetary differential gear reducer is known as a reducer that is small and light, has a high reduction ratio, and can transmit a large torque. An example of this planetary differential gear mechanism is described in Patent Document 1. In Patent Document 1, the sun gear is used as an input and is rotatably supported by the carrier, and the number of teeth supported by the sun gear so as to be revolved is the same. A planetary differential gear mechanism is disclosed in which two fixed internal gears and movable internal gears having different numbers of teeth are simultaneously meshed with the planetary gear, and the rotation of the movable internal gear is decelerated and output. At this time, the planetary gear is constituted by two-stage integrals having different numbers of teeth, and the fixed internal gear and the movable internal gear are meshed with each other to reduce the output. With this configuration, the planetary gear driven by the sun gear revolves along the fixed internal gear while rotating, so that the movable internal gear can transmit a large torque at a high reduction ratio. However, as one of the problems of this mechanism, the planetary gear receives a force from three locations of the sun gear, the fixed internal gear, and the movable internal gear, so that the planetary gear bends and tilts. The carrier supporting the gears is also twisted and tilted by the force received by the planetary gear. If the planetary gear or carrier bends, tilts, twists, etc., the sun gear, fixed internal gear, and movable internal gear that mesh with the planetary gear cause one-sided contact, causing vibration and noise. Rotational transmission accuracy and transmission efficiency up to the output of the toothed gear are deteriorated.

This problem will be described with reference to FIG. 9, FIG. 10, and FIG.
First, FIG. 9 illustrates the arrangement and movement of each gear.
The sun gear 100 meshes with a planetary gear 101 arranged in three equal parts on a carrier (not shown). The planetary gear 101 meshed with the sun gear 100 is also inscribed and meshed with both the fixed internal gear 103 and the movable internal gear 104 at the same time. The rotation direction differs depending on the magnitude relationship between the number of teeth of the fixed internal gear 103 and the movable internal gear 104. In the case of fixed internal gear 103 <movable internal gear 104 in terms of the number of teeth, the input sun gear 100 and the output movable internal gear 104 have the same rotational direction, and the fixed internal gear 103> the movable internal gear 104 In this case, the rotation directions of the input sun gear 100 and the output movable internal gear 104 are opposite to each other. This also reverses the direction of the force that the planetary gear receives from the movable internal gear.

  FIG. 10 schematically shows a force relationship acting on the planetary gear 101 when the fixed internal gear 103 <the movable internal gear 104. S is a basic circle of the sun gear 100, a circle P located on the outer periphery thereof is a basic circle of the planetary gear 101, an R of the outer peripheral arc is a basic circle of the fixed internal gear 103, and M is a basic circle of the movable internal gear 104. Assuming a circle, the direction of the force acting on the teeth (tooth surface) of the planetary gear 101 is indicated by a directional arrow together with the rotation direction of each gear. a is a force received from the sun gear 100, b is a drag received from the fixed internal gear 103, and c is a drag received from the movable internal gear 104. FIG. 11 shows this in the width direction of the planetary gear 101. As shown in FIG. 11, since the meshing positions 103A and 104A of the fixed internal gear 103 and the movable internal gear 104 are different in the axial direction, the planetary gear 101 and the carrier 102 supporting it are bent and inclined. Become. In addition, vibration and noise are generated due to these deflections and inclinations, and there is a problem that efficient and high-accuracy drive transmission cannot be obtained.

  SUMMARY OF THE INVENTION In view of the above-described conventional problems, an object of the present invention is to provide a rotating body driving device and an image forming apparatus that can reduce the inclination generated in a planetary gear and a carrier that supports the planetary gear.

In order to achieve the above-mentioned object, the present invention achieves the sun gear supported and rotated by the main body side plate, a plurality of planetary gears meshing with the sun gear, the planetary gears capable of rotating and revolving around the sun gears. In a rotating body driving device for driving a rotating body through a planetary differential gear reduction mechanism having a freely supporting carrier, a fixed internal gear and a movable internal gear meshing with the planetary gear, respectively, the planetary gear in the planetary gear between the fixed internal gear and the meshing engagement portion and the movable internal gear and meshing meshing portion, and provided with a gear bearing supporting freely with respect to the rotation and the revolution, the rotatable member is detachable drum The movable internal gear is provided on the drum flange of the drum, and when the drum is inserted, the planetary gear and the movable internal gear mesh with each other to reduce the planetary differential gear speed. The driving force input to the structure is transmitted to the drum, and when the drum is inserted, the gear bearing is fitted to the drum flange and rotatably supported, and the planetary flange is supported by the drum flange. Proposed is a rotating body drive device provided with a movable deformation portion that absorbs an angle of deviation and an eccentricity when connected to a differential reduction mechanism .

  Further, in the present invention, it is advantageous that the carrier is supported by a bearing provided across a fixing member on which a main body side plate and the fixed internal gear are formed, and a bearing provided on the fixing member.

  Still further, according to the present invention, it is advantageous that the movable deformation portion is configured by providing a plurality of slits in the drum flange.

Still further, according to the present invention, it is advantageous that the movable deformable portion is configured through a leaf spring at an intermediate portion of the drum flange.
Furthermore, in the present invention, a hole into which the sun gear shaft is inserted is formed in the drum flange, and the sun gear shaft is inserted into the hole when the drum is mounted. It is advantageous if the planetary gears mesh with each other.

According to the present invention, in order to achieve the above object, the rotating body is an image carrier drum, and the image carrier drum is rotationally driven using the rotating body driving device according to any one of claims 1 to 5. An image forming apparatus is proposed.

  According to the present invention, in the planetary differential gear speed reduction mechanism, the planetary gear can suppress the inclinations of the drag directions received from the fixed internal gear and the movable internal gear to be low, and the noise is low, the vibration is low, the efficiency is high, and the accuracy is high. Rotation is possible. Further, since the drive is transmitted by the movable internal gear provided on the image carrier drum flange, the coupling between the speed reducer and the image carrier drum is not required, and the size and cost can be reduced.

1 is a schematic cross-sectional view illustrating an example of an image forming apparatus to which the present invention is applied. It is a section explanatory view showing the rotating body drive concerning the present invention. FIG. 3 is a cross-sectional explanatory view taken along line III-III in FIG. 2. FIG. 3 is an explanatory sectional view showing a state when the image carrier drum of FIG. 2 is mounted. It is a figure which shows the modification of a planetary gear. It is explanatory drawing which shows the movable deformation | transformation part provided in the image carrier drum. It is an enlarged view of the movable deformation | transformation part of FIG. It is a figure which shows the modification of a movable deformation | transformation part. It is explanatory drawing which shows the conventional planetary gear reduction mechanism. It is explanatory drawing which shows the force which acts on a planetary gear. It is explanatory drawing which shows the working force in the width direction of a planetary gear.

Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.
FIG. 1 is a schematic sectional view showing an example of an image forming apparatus. The image forming apparatus shown here includes a plurality of image carrier drums 1Y, 1M, 1C, and 1K made of a photosensitive member, and an intermediate transfer belt 2 made of an endless belt in contact with the peripheral surface of these image carrier drums. Have. The intermediate transfer belt 2 is wound around the support rollers 3, 4, 5, guided by the guide roller 6, and rotationally driven in the direction of arrow A by a driving device (not shown). On the other hand, the image carrier drums 1Y to 1K are also driven to rotate counterclockwise in FIG.

  In each of the image carrier drums 1Y to 1K, toner images of different colors are formed. In the illustrated example, a yellow toner image, a magenta toner image, a cyan toner image, and a black toner image are displayed on the image carrier drums 1Y to 1Y. 1K is formed. The toner image formed on the surface of each image carrier drum is transferred to the surface of the intermediate transfer belt 2.

  The configuration in which a toner image is formed on each image carrier drum 1Y, 1C, 1M, 1K and the toner image is transferred to the intermediate transfer belt 2 is substantially the same except that the color of the toner image is different. Therefore, only a configuration in which a toner image is formed on one of the image carrier drums 1Y and the toner image is transferred to the intermediate transfer belt 2 will be described. As shown in FIG. 1, when the image carrier drum 1Y is driven to rotate counterclockwise in FIG. 1, the image carrier drum 1Y has a predetermined polarity by a charging device comprising a charging charger 7Y to which a charging voltage is applied. Charged. The charged image carrier drum 1Y is irradiated with a light-modulated laser beam L emitted from an optical writing device (not shown), whereby an electrostatic latent image is formed on the image carrier drum 1Y. This electrostatic latent image is visualized as a yellow toner image by the developing device 8Y.

  A primary transfer device composed of a transfer roller 9Y is disposed on the opposite side of the intermediate transfer belt 2 from the image carrier drum 1Y, and a transfer voltage is applied to the transfer roller 9Y to form the image carrier drum 1Y. The toner image thus transferred is transferred onto the intermediate transfer belt 2 that rotates in the direction of arrow A. The transfer residual toner adhering to the image carrier drum 1Y after the toner image transfer is removed by the cleaning device 10Y, and the residual charge is removed by the charge remover 11Y to prepare for the next image formation.

  In exactly the same manner as described above, magenta toner images, cyan toner images, and black toner images are formed on the image carrier drums 1M, 1C, and 1K shown in FIG. 1, respectively. The toner images are sequentially transferred onto the transferred intermediate transfer belt 2 and a combined toner image is formed on the intermediate transfer belt 2. The transfer residual toner on each of the image carrier drums 1M, 1C, and 1K after the toner image transfer is removed by the cleaning device is not different from the case of the first image carrier drum 1Y. In FIG. 1, for each image forming element provided around each image carrier drum 1M, 1C, 1K, Y attached to each symbol of each image forming element provided around image carrier drum 1Y. Instead of these, symbols with M, C, and BK are added.

  On the other hand, a transfer roller 12 as an example of a secondary transfer device is disposed on the lowermost support roller 5 of the support rollers around which the intermediate transfer belt 2 is wound, with the intermediate transfer belt 2 interposed therebetween. A recording medium P made of, for example, paper or a resin sheet is fed between the transfer roller 12 and the intermediate transfer belt portion wound around the support roller 5 as indicated by an arrow B. At this time, a predetermined transfer voltage is applied to the transfer roller 12, whereby the composite toner image on the intermediate transfer belt 2 is transferred onto the recording medium P. Transfer residual toner adhering to the intermediate transfer belt 2 after the toner image is transferred to the recording medium P is removed by a belt cleaning device (not shown). Further, the recording medium P to which the toner image has been transferred is further conveyed leftward in FIG. 1, and the toner image is fixed on the recording medium P when passing through the fixing device 13. The recording medium that has passed through the fixing device 13 is discharged onto a paper discharge tray (not shown).

2 is a longitudinal sectional view showing a rotating body driving apparatus according to the present invention for driving the image carrier drum 1, and FIG. 3 is a sectional view taken along line III-III in FIG.
2 and 3, reference numeral 20 denotes a drive motor for driving the image carrier drum 1. The drive motor 20 is fixed to the outside of the image carrier drum 1 if it is located inside the main body side plate 14. Yes. The rotating body drive device according to the present embodiment is configured to transmit the rotation of the drive motor 20 to the image carrier drum 1 while greatly reducing the rotation via the planetary differential gear reduction mechanism.

The configuration of the planetary differential gear reduction mechanism is as follows.
A sun gear 22 is fixed to the motor shaft 21 of the drive motor 20, and a plurality of planet gears 23 in the present embodiment, three planet gears 23 are arranged equally (every 120 °) around the sun gear 22. 22 is engaged. The planetary gear 23 is supported by the carrier 25 so as to be rotatable via the planetary gear shaft 24 and revolves while rotating around the sun gear 22. Further, the planetary gear 23 meshes with a fixed internal gear 27 provided on the inner peripheral side of the fixing member 26 fixed to the main body side plate 14, and the planetary gear 23 revolves simultaneously with rotation while meshing with the fixed internal gear 27. It will also do. The fixed internal gear 27 is positioned with the main body side plate 14 via a bearing 28 </ b> A, and the bearing 28 </ b> A also has a coaxial accuracy at the boss portion 29 with the motor 20. The bearing 28A is provided straddling the main body side plate 14 and the fixing member 26, and the carrier 25 is cantilevered and supported rotatably at two locations of the bearing 28A and the bearing 28B provided on the fixing member 26. Has been issued. In this way, since the carrier 25 is supported at two locations via the bearings 28A and 28B, the carrier 25 is configured not to fall even if a radial load is applied.

  The planetary gear 23 also meshes with a movable internal gear 30 provided on the inner peripheral surface of the drum flange 15 of the image carrier drum 1. Since the fixed internal gear 27 and the movable internal gear 30 are simultaneously meshed with the planetary gear 23 as described above, if the planetary gear 23 has the same module and the same number of teeth at each meshing portion, the planetary gear 23 is provided. When one rotation around the fixed internal gear 27 is made, rotation of the difference in the number of teeth from the fixed internal gear 27 is transmitted to the movable internal gear 30.

  In the rotating body drive device shown in FIG. 2, the tooth number 23 </ b> A of the planetary gear 23 that meshes with the fixed internal gear 27 of the planetary gear 23 and the tooth part 23 </ b> B of the planetary gear 23 that meshes with the movable internal gear 30 have the same number of teeth. ing. In the rotating body driving device of the present embodiment, a step is provided at an intermediate portion between the tooth portion 23A meshing with the fixed internal gear 27 of the planetary gear 23 and the tooth portion 23B meshing with the movable internal gear 30, and a gear bearing is provided at the intermediate portion. 31 is arranged. The carrier 25 is provided with a support 25A between the planetary gears, and the gear bearing 31 is supported by the support 25A.

  The movable internal gear 30 is provided integrally with the drum flange 15, and the drum flange 15 is configured to be fitted with a gear bearing 31 provided at an intermediate portion of the planetary gear 23 through an opening. As can be seen from FIG. 3, when the planetary gear 23 revolves, it rotates along the inside of the opening of the drum flange 15. On the contrary, the drum flange 15 is rotated by the drive transmission decelerated to the movable internal gear 30 while being supported by the three gear bearings 31, and the image carrier drum 1 fixed to the drum flange 15 is further rotated. To do. With such a configuration, the coaxial accuracy of the planetary gear 30 and the movable internal gear 23 is maintained, and the meshing is transmitted smoothly.

  A gap between the fixed member 26 provided with the fixed internal gear 27 and the drum flange 15 provided with the movable internal gear 30 is blocked by a sealing material 32 so that dust or the like does not enter the gear transmission mechanism.

In FIG. 4, the case where the image carrier drum 1 is inserted will be described.
The motor shaft 21 becomes the shaft of the sun gear 20, extends to the drum flange 15 side, and is configured to be fitted with a hole 16 provided at the center of the drum flange 15. The entrance side of the hole 16 is tapered, and the tip 21A of the motor shaft 21 is also spherical or tapered to facilitate insertion. As shown in FIG. 4, when the image carrier drum 1 is inserted from the direction of the arrow, the motor shaft 21 first enters the hole 16 of the drum flange 15, and when the image carrier drum 1 is further inserted, the motor shaft 21 is inserted. , While being guided along the hole 16, the movable internal gear 30 and the planetary gear 23 mesh with each other while maintaining the coaxial accuracy.

  Since the rotating body driving apparatus configured as described above does not drive-connect the driving source and the image carrier drum 1 via a coupling or the like, the length of the drum in the axial direction can be shortened, and the compactness of the apparatus can be achieved. It can contribute to the conversion. Further, in the present invention, the planetary differential gear reduction mechanism includes a planetary gear meshing with the tooth portion 23A of the planetary gear 23 meshing with the fixed internal gear 27 of the planetary gear 23 and the movable internal gear 30 as shown in FIG. The present invention can also be applied to a configuration in which the tooth portion 23B of the gear 23 is decelerated using the planetary gear 23 of a two-stage gear having a different number of teeth.

FIG. 6 is an explanatory plan view showing a state in which the image carrier drum 1 is mounted on the main body.
The back side of the main body side plate 14 where the rotating body driving device of the image carrier drum 1 is provided is supported by the planetary differential gear speed reduction mechanism via a drum flange 15 provided with a movable deformation portion. The front side of the image carrier drum 1 has a drum shaft rotatably supported on a face plate 14A via a bearing 14B, and the face plate 14A is fixed in front of the main body side plate. The image carrier drum 1 can be detached from the apparatus main body by removing the face plate 14A from the front of the main body side plate. If there is an error in the positional accuracy of the speed reduction mechanism and the face plate 14A when the image carrier drum 1 is mounted, the image carrier drum 1 is supported obliquely like the image carrier drum 1 shown by the broken line in FIG. In such a state, contact between the movable internal gear 30 provided on the drum flange 15 and the planetary gear 23 is caused by one-sided contact, and the drive transmission accuracy is deteriorated.

  Therefore, in the present embodiment, the drum flange 15 is provided with a movable deformation portion to absorb the declination and eccentricity of the movable internal gear 30 with respect to the planetary gear 23 to suppress the one-side contact. As a specific configuration of the movable deformable portion shown in FIG. 7, a plurality of alternate slits 17 are provided on one side of the drum flange 15 and the opposite side to constitute the movable deformable portion.

  In FIG. 8, another movable deformation portion is formed by dividing the drum flange 15 into two parts 15 </ b> A and 15 </ b> B and connected via a leaf spring 18. The leaf spring 18 is fixed by convex portions 19 provided at different locations of the flanges 15 and A15B. Thus, by connecting with the leaf | plate spring 18, it becomes a structure with high torsional rigidity of a movable deformation | transformation part, and rotation in a movable deformation | transformation part will be transmitted correctly.

  In the above-described embodiment, the rotating body driving device according to the present invention has been described as an apparatus that drives an image carrier drum. However, the rotating body driving device according to the present invention is limited to an image bearing drum. Alternatively, it may be a rotating body such as a driving roller or a developing roller of the intermediate transfer belt.

DESCRIPTION OF SYMBOLS 1 Image carrier drum 15 Drum flange 16 Hole 17 Slit 18 Leaf spring 20 Drive motor 22 Sun gear 23 Planetary gear 25 Carrier 27 Fixed internal gear 30 Movable internal gear 31 Gear bearing

JP 2007-255517 A

Claims (6)

A sun gear that is supported by the main body side plate and rotationally driven; a plurality of planetary gears that mesh with the sun gear; a carrier that rotatably supports the planetary gear and revolves around the sun gear; and the planetary gear. In a rotating body drive device that drives a rotating body via a planetary differential gear reduction mechanism having a fixed internal gear and a movable internal gear that mesh with each other,
A gear bearing is provided between the meshing portion meshing with the fixed internal gear and the meshing portion meshing with the movable internal gear in the planetary gear, and freely supports the rotation and the revolution .
The rotating body is composed of a detachable drum, the movable internal gear is provided on a drum flange of the drum,
When the drum is inserted, the planetary gear and the movable internal gear mesh with each other, the driving force input to the planetary differential gear reduction mechanism is transmitted to the drum, and when the drum is inserted, A gear bearing is fitted to the drum flange and rotatably supported,
A rotating body driving device characterized in that a movable deforming portion for absorbing a deviation angle and an eccentricity when the drum flange is connected to the planetary differential reduction mechanism is provided on the drum flange . 2. The rotating body drive device according to claim 1 , wherein the carrier is supported by a bearing provided across a main body side plate and a fixed member on which the fixed internal gear is formed, and a bearing provided on the fixed member. A rotating body drive device characterized by that. 2. The rotating body drive device according to claim 1 , wherein the movable deformation portion is configured by providing a plurality of slits in the drum flange. 3. The rotating body drive device according to claim 1 , wherein the movable deformation portion is configured through a leaf spring at an intermediate portion of the drum flange. 5. The rotating body drive device according to claim 1 , wherein a hole into which the shaft of the sun gear is inserted is formed in the drum flange, and the sun gear is inserted into the hole when the drum is mounted. A rotating body driving device characterized in that the movable internal gear and the planetary gear mesh with each other while a shaft is inserted.   6. An image forming apparatus, wherein the rotating body is an image carrier drum, and the image carrier drum is rotationally driven using the rotating body driving device according to claim 1.

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