JP2013164562A - Mounting structure of drive transmission member, drive unit and image formation apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a mounting structure of a drive transmission member, a drive unit and an image formation apparatus capable of suppressing backlash from being generated at a gap between the drive transmission member and a shaft, without eccentricity of the drive transmission member to the shaft, while allowing easy mounting and dismounting of the drive transmission member with regard to the shaft.SOLUTION: A mounting structure of a drive transmission member includes: a rotatable shaft 130; and a drive transmission member having an opening for receiving insertion of the shaft 130 and configured to be mounted to the shaft 130 so as to rotate in synchronization with the shaft 130. An outer peripheral surface of the shaft 130 has at least three grooves 133 arranged such that a planar surface passing through each center line thereof includes the center of rotation of the shaft 130. Each groove 133 has energization means 140 retractable inside the groove 133. The energization means 140 has: a pressure action portion 141 that presses an inner peripheral surface of the opening and is longer than the inner peripheral surface of the opening; and a pressure member 142 arranged between the pressure action portion 141 and a bottom face 133a of the groove 133, and configured to press the pressure action portion 141 toward the inner peripheral surface of the opening.

Description

  The present invention relates to a mounting structure of a drive transmission member that transmits driving from a driving source to a driven part, a driving device to which the mounting structure is applied, and an image forming apparatus including the driving device.

  In a machine, a drive (power) transmission element is often used to transmit drive (power) from part to part. For example, in an image forming apparatus using an electrophotographic system, many rotating members are provided, and a drive transmission member such as a gear is often used to transmit driving to the rotating member.

  More specifically, an intermediate transfer type image forming apparatus using an electrophotographic system has a photosensitive drum on which an electrostatic latent image is formed, and an intermediate transfer belt disposed opposite to the photosensitive drum. In addition, such an image forming apparatus includes a primary transfer device that transfers a toner image from a photosensitive drum to an intermediate transfer belt, a secondary transfer device that transfers a toner image from the intermediate transfer belt to a transfer material, and a toner image on the transfer material. A fixing device for fixing;

  This type of image forming apparatus is provided with a driving device that drives a driven unit such as a photosensitive drum, an intermediate transfer belt, a primary transfer device, a secondary transfer device, and a fixing device. As the drive device, a device provided with a drive source such as a motor and a drive transmission device such as a gear train for transmitting the drive force from these drive sources to the driven unit is used.

  The gears constituting the gear train are generally provided with a through hole at the center thereof. By passing the through hole through a shaft supported by the driven unit, the gear train is attached to the driven unit so as to be rotatable independently of or in synchronization with the shaft.

  However, when the above-described gear mounting method is employed, if the gap between the shaft and the through hole of the gear is large, rattling may occur and the gear may cause uneven rotation. As a result, the image quality of the formed image may be degraded.

  In view of the above problems, an expansion member having a high coefficient of thermal expansion is provided on the outer peripheral surface of the shaft or the inner surface of the gear, and the difference between the values of thermal expansion is used to determine the difference between the shaft and the gear through-hole. (Patent Document 1).

  There is also a structure in which a gear is press-fitted into the shaft to fill a gap between the shaft and the through hole of the gear.

  Further, there is a structure in which a screw hole is provided in the shaft, the shaft and the through hole of the gear are fitted, and the gear and the shaft are screwed after the gear is inserted into the shaft.

JP 2002-257131 A

  However, the conventional drive transmission member mounting structure as described above has a problem to be improved.

  For example, in the mounting structure of Patent Document 1, for example, when there is an environment with a temperature difference in one day, the coefficient of thermal expansion varies with time, so the gap relationship between the shaft and the through hole of the gear is not constant. Absent. Therefore, in some cases, rattling may occur between the shaft and the through hole of the gear.

  In addition, in the mounting structure in which the gear is press-fitted into the shaft, for example, it becomes difficult to attach and detach the gear during maintenance, and the maintainability may be impaired.

  Furthermore, in a mounting structure in which a screw hole is provided in the shaft and the gear and the shaft are screwed together, it is difficult to achieve a coaxial degree of the gear with respect to the shaft. Therefore, it may be eccentric, resulting in uneven rotation.

  Accordingly, an object of the present invention is to prevent the drive transmission member from being eccentric with respect to the shaft and to suppress the occurrence of play in the gap between the drive transmission member and the shaft, and to easily attach and detach the drive transmission member to and from the shaft. It is an object to provide a drive transmission member mounting structure, a driving device, and an image forming apparatus.

  The above object is achieved by a drive transmission member mounting structure, a drive device, and an image forming apparatus according to the present invention. In summary, the present invention includes a rotatable shaft and an opening into which the shaft is inserted along a rotational axis direction of the shaft, and a drive attached to the shaft so as to rotate in synchronization with the shaft. A transmission member, and at least three grooves are formed on an outer peripheral surface of the shaft so that a plane passing through each center line includes the rotation center of the shaft. An urging means that can be retracted is provided inside the urging means. The urging means presses the inner peripheral surface of the opening, and the length in the direction in which the shaft is inserted into the opening is the length of the opening. A pressing action portion that is longer than the inner peripheral surface; and a pressing member that is disposed between the pressing action portion and the bottom surface of the groove and presses the pressing action portion toward the inner peripheral surface of the opening. The drive transmission member mounting structure is characterized by the above.

  According to another aspect of the present invention, a drive source, a drive transmission member for transmitting a drive force from the drive source to the driven portion, and a drive force transmitted to the drive transmission member are transmitted to the driven portion. There is provided a drive device characterized in that the drive transmission member mounting structure with respect to the shaft is the drive transmission member mounting structure of the present invention.

  According to another aspect of the present invention, there is provided an image forming apparatus comprising the driving device according to the present invention and a driven portion driven by the driving device.

  According to the present invention, it is possible to suppress the play of the gap between the drive transmission member and the shaft without the drive transmission member being eccentric with respect to the shaft, and the drive transmission member can be easily attached to and detached from the shaft. .

1 is a schematic cross-sectional view illustrating an overall configuration of an image forming apparatus according to an embodiment of the present invention. It is a side view of the drum drive device which is one Example of the drive device which concerns on this invention. It is sectional drawing which shows the state before inserting a drum axis | shaft in a drum gear in the attachment structure of the drum gear which is one Example of the attachment structure of the drive transmission member which concerns on this invention. It is a perspective view of the gear attachment part of a drum axis | shaft which shows the biasing unit with which the attachment structure of the drum gear of FIG. 3 is provided. 4A is a front view and FIG. 4B is a cross-sectional view illustrating a state where a drum shaft is inserted into the drum gear in the drum gear mounting structure of FIG. 3. It is sectional drawing of the gear attachment part of the drum axis | shaft which shows the urging | biasing unit with which the attachment structure of the drum gear which is another Example of the attachment structure of the drive transmission member which concerns on this invention is provided. It is a front view which shows the state which inserted the drum axis | shaft in the drum gear in the mounting structure of the drum gear which is further another Example of the mounting structure of the drive transmission member which concerns on this invention.

  Hereinafter, a drive transmission member mounting structure, a drive device, and an image forming apparatus according to the present invention will be described in more detail with reference to the drawings.

Example 1
1. First, an overall configuration and operation of an embodiment of an image forming apparatus including a drive transmission member mounting structure according to the present invention and a driving device to which the mounting structure is applied will be described.

  FIG. 1 is a schematic cross-sectional view showing an overall configuration of an embodiment of an image forming apparatus according to the present invention. The image forming apparatus 1 according to the present exemplary embodiment has a tandem type image forming apparatus (for example, a copier, a printer, and a fax machine) that employs an intermediate transfer method capable of forming a full-color image using an electrophotographic method. Multifunctional machine).

  The image forming apparatus 1 has four image forming units PY, PM, PC, and PK arranged in parallel in the horizontal direction in the apparatus main body 10 as a plurality of image forming units (stations). The first, second, third, and fourth image forming units PY, PM, PC, and PK respectively have yellow (Y) component, magenta (M) component, cyan (C) component, and black (K) component images. Form.

  In this embodiment, the configurations and operations of the image forming units PY, PM, PC, and PK are substantially the same except that the color of the toner used is different. Therefore, in the following, when there is no particular need to distinguish, subscripts Y, M, C, and K that indicate elements for any color will be omitted, and a general description will be given.

  The image forming unit P includes a photosensitive drum 11 that is a drum-shaped electrophotographic photosensitive member as an image carrier. The photosensitive drum 11 is rotationally driven at a predetermined process speed (circumferential speed) in the direction of the arrow R1 (counterclockwise) in the figure by a drum motor 110 (FIG. 2) as a drive source of the driving device 100 (FIG. 2). An independent drive source may be provided for each of the photosensitive drums 11Y, 11M, 11C, and 11K of each of the image forming units PY, PM, PC, and PK, or a drive source may be provided for some or all of the photosensitive drums 11. It may be common. In this embodiment, it is assumed that an independent drive source is provided.

  Around the photosensitive drum 11, the following means are arranged in order along the rotation direction. First, there is a charging device (corona charger) 12 as a charging means for uniformly charging the surface of the photosensitive drum 11. Next, there is an exposure device (laser scanner unit) 13 as an exposure unit that irradiates the photosensitive drum 11 with a laser beam based on image information and forms an electrostatic latent image (electrostatic image) on the photosensitive drum 11. Next, the developing device 14 is a developing unit that develops a developer image (toner image) by attaching toner to the electrostatic latent image. Next, an intermediate belt unit 20 as an electrostatic transfer device that transfers a toner image on the photosensitive drum 11 onto a transfer material S such as paper. Next, a cleaning device 16 is provided as a cleaning unit that removes toner (transfer residual toner) remaining on the surface of the photosensitive drum 11 after the transfer process.

  The intermediate transfer unit 20 has an endless belt-like intermediate transfer belt 17 as an intermediate transfer member so as to face each photosensitive drum 11 of each image forming portion P. The intermediate transfer belt 17 is stretched around a drive roller 21, a tension roller 22, and a secondary transfer counter roller 23 as a plurality of support rollers, and is rotated by the drive roller 21 in the direction indicated by the arrow R2. On the inner peripheral surface side of the intermediate transfer belt 17, a primary transfer roller 15 that is a roller-type transfer member serving as a primary transfer unit is disposed at a position facing each photosensitive drum 1. The primary transfer roller 15 is pressed against the photosensitive drum 11 via the intermediate transfer belt 17 to form a primary transfer portion (primary transfer nip) N1 where the intermediate transfer belt 17 and the photosensitive drum 11 are in contact with each other. A secondary transfer roller 18, which is a roller-type transfer member serving as a secondary transfer means, is disposed on the outer peripheral surface side of the intermediate transfer belt 17 at a position facing the secondary transfer counter roller 23. The secondary transfer roller 18 is pressed against the secondary transfer counter roller 23 via the intermediate transfer belt 17, and a secondary transfer portion (secondary transfer nip) where the secondary transfer roller 18 and the intermediate transfer belt 17 come into contact with each other. N2 is formed.

  At the time of image formation, the photosensitive drum 11 that is rotationally driven in the direction of the arrow R1 in the figure is uniformly charged to a predetermined polarity and potential by the charging device 12 during the rotation process. The charged photosensitive drum 11 is subjected to optical image exposure by the exposure device 13, and an electrostatic latent image (electrostatic image) corresponding to image information is formed on the photosensitive drum 11. The electrostatic latent image formed on the photosensitive drum 11 is developed (visualized) as a toner image when toner is supplied by the developing device 14. The toner image formed on the photosensitive drum 11 is primarily transferred onto the intermediate transfer belt 17 by the primary transfer roller 15 in the primary transfer portion N1. For example, when forming a full-color image, the toner image formed on each photosensitive drum 11 of each image forming unit P as described above is superimposed on the intermediate transfer belt 17 in each primary transfer unit N1. Primary transfer in sequence. On the other hand, toner remaining on the photosensitive drum 1 without being primary transferred (primary transfer residual toner) is removed from the photosensitive drum 1 by the cleaning device 16 and collected.

  The toner image transferred onto the intermediate transfer belt 17 is secondarily transferred onto the transfer material S by the secondary transfer roller 18 in the secondary transfer portion N2. The transfer material S is sent out from a transfer material cassette (not shown) and is conveyed to the secondary transfer portion N2 in synchronization with the toner image on the intermediate transfer belt 17 by a registration roller (not shown). The transfer material S onto which the toner image has been transferred is heated and pressurized in a fixing device 19 as a fixing unit. As a result, the toner image is fixed on the transfer material S. Thereafter, the transfer material S is discharged to the outside of the apparatus main body 10. Further, toner (secondary transfer residual toner) or the like remaining on the intermediate transfer belt 17 without being subjected to secondary transfer is removed from the intermediate transfer belt 17 and collected by an intermediate transfer belt cleaning device (not shown). .

2. Next, an embodiment of a drive transmission member mounting structure according to the present invention and an embodiment of a drive device to which the mounting structure is applied will be described.

  In this embodiment, the drive transmission member mounting structure according to the present invention is embodied in a drive device (drum drive device) 100 that rotationally drives the photosensitive drum 11. The drum driving device 100 includes a driving source and a driving transmission device that transmits a driving force from the driving source to the photosensitive drum 11 as a driven portion.

  FIG. 2 shows a configuration of the drum driving device 100 of the present embodiment. The drum driving device 100 includes a drum motor 110 as a driving source, and a gear train 120 that transmits a driving force from the drum motor 110 to the drum shaft 130. The drum shaft 130 constitutes a rotating shaft of the photosensitive drum 11, and finally transmits the driving force transmitted from the drum motor 110 via the gear train 120 to the photosensitive drum 11. The gear train 120 includes a motor gear 121 that is directly cut by the rotating shaft 111 of the drum motor 110 and a drum gear 122 that is attached to the drum shaft 130. The drum motor 110 is attached to an attachment sheet metal 150 fixed to the apparatus main body 10.

  Next, an attachment structure for the drum gear 122 as a drive transmission member will be described with reference to FIGS.

  In the present embodiment, the drum gear 122 includes a gear flange 123 on the radially inner side and a gear body 124 on the radially outer side of the gear flange 123. The gear flange 123 is made of die casting in order to ensure rigidity, and is press-fitted and fixed near the center of the gear main body 124. As a material of the gear flange 123, aluminum or zinc can be preferably used. A substantially cylindrical through hole 125 is provided at the rotation center of the gear flange 123 as an opening concentric with the gear flange 123.

  In the through hole 125, the drum shaft 130 is inserted along the rotational axis direction from the base end 125 b side in the axial direction. The gear attachment portion 131 that is passed through the through hole 125 of the gear flange 123 at one end portion in the axial direction of the drum shaft 130 has a substantially cylindrical shape. However, a key groove 132 and a retracting groove 133, which will be described in detail later, are formed on a part of the outer peripheral surface 131c of the gear mounting portion 131. The length L1 from the distal end 131a to the proximal end 131b in the axial direction of the gear attachment portion 131 is larger than the length L2 from the distal end 125a to the proximal end 125b in the axial direction of the through hole 125. As an example, in this embodiment, L1 is 65 mm and L2 is 36 mm. The drum shaft 130 is inserted into the through hole 125 until the stepped portion 134 located at the base end 131b of the gear mounting portion 131 contacts the edge 125d of the through hole 125 on the base end 125b side. The inner diameter of the through hole 125 and the gear mounting portion 131 are set so that a predetermined gap (for example, about 0.03 mm) is provided between the inner peripheral surface 125 c of the through hole 125 and the outer peripheral surface 131 c of the gear mounting portion 131. The outer diameter is set. As an example, in this embodiment, the outer diameter of the gear mounting portion 131 is 18.0135 mm, and the inner diameter of the through hole 125 is 17.985 mm.

  Further, a key groove 132 as an engaged portion is provided on the outer peripheral surface 131c of the gear mounting portion 131 so that the drum gear 122 and the drum shaft 130 rotate integrally. The keyway 132 has a predetermined width D3 in the circumferential direction of the drum shaft 130, and has a predetermined height (depth) H3 in the radial direction. As an example, in this embodiment, D3 is 3 mm and H3 is 1.3 mm. Further, the key groove 132 extends along the axial direction of the drum shaft 130 from the distal end 131a to the proximal end 131b of the gear mounting portion 131. On the other hand, a convex key 126 that fits the width D3 and height H3 of the drum shaft 130 of the key groove 132 is formed on the inner peripheral surface 125c of the through hole 125 as an engaging portion. The key 126 extends along the axial direction of the through hole 125 (the insertion direction of the drum shaft 130) from the front end 125a to the base end 125b of the through hole 125. Note that a convex portion as an engaging portion may be provided on the drum shaft 130 side, and a concave portion as an engaged portion may be provided on the gear flange 123 side.

  Further, on the outer peripheral surface 131 c of the gear mounting portion 131, apart from the key groove 132, a retracting groove 133 for retracting an urging means described later is provided. The retreat groove 133 has a predetermined width D1 in the circumferential direction of the drum shaft 130 and a predetermined height (depth) H1 in the radial direction. As an example, in this embodiment, D1 is 3.007 mm and H1 is 1.9 mm. The retreat grooves 133 are provided at three locations on the outer peripheral surface 131c of the gear mounting portion 131 so that the plane formed by connecting the center lines in the circumferential direction of the drum shaft 130 includes the rotation center of the drum shaft 130. ing. The retreat groove 133 extends along the axial direction of the drum shaft 130 from the distal end 131a to the proximal end 131b of the gear attachment portion 131.

  In this embodiment, the angle formed by the straight line connecting the rotation center of the drum shaft 130 and the center line in the circumferential direction of the drum shaft 130 of each bottom surface 133a of the adjacent retreat groove 133 is 137 °, 130 °, 93 It is °.

  An urging unit 140 as an urging unit is attached so as to be evacuated inside the evacuation groove 133.

  The urging unit 140 includes a pressing plate 141 as a pressing action portion that is disposed so as to face the retraction groove 133 provided in the gear mounting portion 131. The length L3 from the front end 141c to the base end 141d in the axial direction of the pressing plate 141 is longer than the length L2 of the through hole 125 in the axial direction. Further, the length L3 of the pressing plate 141 is equal to or shorter than the length L1 of the gear mounting portion 131. As an example, in this embodiment, L3 is 41 mm. The pressing plate 141 has a width D2 that is equal to or smaller than the width D1 of the retracting groove 133 in the circumferential direction of the drum shaft 130. As an example, in this embodiment, D2 is 2.987 mm. In this embodiment, the thickness T of the pressing plate 141 is 1.0 mm. In the present embodiment, the base end 141 d of the pressing plate 141 is disposed at substantially the same position as the base end 131 b of the gear attachment portion 131. As a material of the pressing plate 141, for example, a galvanized steel plate (for example, Gincoat (trademark)), a SUS sheet metal, or the like can be preferably used.

  Further, the urging unit 140 has a spring (compression coil spring) 142 as a pressing member so as to be sandwiched between the pressing plate 141 and the retracting groove 133. In the present embodiment, the springs 142 are arranged at three locations along the axial direction of the pressing plate 141 and the retracting groove 133. Thus, in this embodiment, as will be described later, the inner periphery of the through hole 125 by the single urging unit 140 including the pressing plate 141 and the three springs 142 is disposed in the through hole 125. The pressing force against the surface 125c is set to be 200 gf.

  The urging unit 140 including the pressing plate 141 and the spring 142 may be supported on the drum shaft 130 by an arbitrary method. In this embodiment, the spring 142 is fixed to the inner surface (the inner surface in the radial direction of the drum shaft 130) 141b of the pressing plate 141 and the bottom surface 133a of the retreat groove 133 by the fixing means, so that the urging unit 140 is 130. As a fixing means, any method such as engagement and adhesion can be used.

  Before the gear mounting portion 131 is inserted into the through hole 125, the outer surface (the outer surface in the radial direction of the drum shaft 130) 141 a of the pressing plate 141 is radially outward of the drum shaft 130 from the outer peripheral surface 131 c of the gear mounting portion 131. Placed in. That is, the distance H2a from the bottom surface 133a of the retracting groove 133 in the radial direction of the drum shaft 130 to the outer surface 141a of the pressing plate 141 at this time is larger than the height H1 of the retracting groove 133. As an example, H2a is about 4 mm. Therefore, the diameter of the circumscribed circle of the outer surface 141 a of the three pressing plates 141 is larger than the diameter of the outer peripheral surface 141 a of the gear mounting portion 131.

  When the gear mounting portion 131 is inserted into the through hole 125, the pressing plate 141 can be retracted into the retreat groove 133 by pressing the urging unit 140 inward in the radial direction of the drum shaft 130. . Typically, an operator presses with a hand (finger). Thereby, a gap can be generated between the inner peripheral surface 125 c of the through hole 125 and the outer surface of the pressing plate 141, and the gear attachment portion 131 can be easily inserted into the through hole 125. Typically, the distance H2b from the bottom surface 133a of the retracting groove 133 in the radial direction of the drum shaft 130 to the outer surface 141a of the pressing plate 141 at this time is equal to or less than the height H1 of the retracting groove 133. In this case, the diameter of the circumscribed circle of the outer surface 141 a of the three pressing plates 141 is equal to or smaller than the diameter of the outer peripheral surface of the gear mounting portion 131 of the drum shaft 130. However, if a gap is generated between the inner circumferential surface 125c of the through hole 125 and the outer surface of the pressing plate 141, and the gear mounting portion 131 can be easily inserted into the through hole 125, the distance H2b is The height H <b> 1 may not be less than or equal to 133. As an example, in this embodiment, H2b is about 2 mm.

  In addition, after the front end 141c of the pressing plate 141 enters the inside of the through hole 125, the pressing of the urging unit 140 toward the inner side in the radial direction of the drum shaft 130 may be released. Thereafter, the gear mounting portion 131 can be inserted into the through hole 125 so as to rub the pressing plate 141 and the inner peripheral surface 125 c of the through hole 125.

  After the gear attachment portion 131 is inserted into the through hole 125, the pressing plate 141 is urged toward the inner peripheral surface 125 c of the through hole 125 by the elastic force of the spring 142. As a result, there is no backlash between the drum gear 122 and the drum shaft 130. Therefore, it is possible to suppress the occurrence of poor image quality due to the uneven rotation of the photosensitive drum 11. The length L3 in the axial direction of the pressing plate 141 is longer than the length L2 in the axial direction of the through hole 125, and the base end 141d of the pressing plate 141 and the base end 125b of the through hole 125 are disposed at substantially the same position. . Therefore, the pressing plate 141 presses the inner peripheral surface 125 a of the through hole 125 over the entire area of the through hole 125 in the axial direction. As a result, rattling between the drum gear 122 and the drum shaft 130 can be eliminated more reliably.

  On the other hand, for example, when the drum gear 122 is removed from the drum shaft 130 during maintenance, the exposed portion 141e of the pressing plate 141 of the urging unit 140 that is exposed to the outside of the drum gear 122 is moved in the radial direction of the drum shaft 130. Press inward. As a result, the pressing plate 141 can be retracted into the retracting groove 133. Typically, an operator presses with a hand (finger). Accordingly, a gap can be generated between the inner peripheral surface 125a of the through hole 125 and the outer surface 141a of the pressing plate 141, and the drum gear 122 can be easily detached from the drum shaft 130.

  Thus, in this embodiment, the drive transmission member mounting structure includes the rotatable shaft 130 and the opening 125 into which the shaft 130 is inserted along the rotation axis direction of the shaft 130, and is synchronized with the shaft 130. And a drive transmission member 122 attached to the shaft 130 so as to rotate. At least three grooves 133 are formed on the outer peripheral surface 131 c of the shaft 130 so that a plane passing through each center line includes the rotation center of the shaft 130. Each groove 133 is provided with an urging means 140 that can be retracted inside the groove 133. The biasing means 140 has a pressing action portion 141 that presses the inner peripheral surface 125 a of the opening 125 and has a longer length in the direction in which the shaft 130 is inserted into the opening 125 than the inner peripheral surface 125 a of the opening 125. The biasing means 140 includes a pressing member 142 that is disposed between the pressing action portion 141 and the bottom surface 133 a of the groove 133 and presses the pressing action portion 141 toward the inner peripheral surface 125 a of the opening 125. Here, being able to retreat inside the groove 133 includes not only the case where the entire biasing means 140 is hidden in the groove 133 but also the case where a part of the biasing means 140 is hidden. That is, it is only necessary that the biasing means 140 can be sufficiently hidden in the groove 133 so as not to prevent the insertion of the shaft 130 into the opening 125. Further, according to the present embodiment, a drum driving device 100 as a driving device using this mounting structure is provided. Furthermore, according to the present embodiment, an image forming apparatus 1 including the drum driving device 100 as the driving device is provided. In this embodiment, the gear train 120 (motor gear 121, drum gear 122), drum shaft 130, urging unit 140, and the like constitute a drive transmission device.

  In the present embodiment, the opening 125 provided in the gear 122 is a through hole that is open at both ends in the axial direction, but may be open at only one end. For example, the end corresponding to the front end 125a side of the through hole 125 in this embodiment is closed, and the exposed portion 141e of the pressing plate 141 of the biasing unit 140 is formed on the base end 125b side. it can.

  Further, the drive transmission member is not limited to a gear, and may be, for example, a friction wheel.

  In this embodiment, Gincoat (trademark) is used as the material of the pressing plate 141. However, the present invention is not limited to this, and a resin material such as POM may be used.

  In this embodiment, the spring (compression coil spring) 142 is used as the pressing member. However, the present invention is not limited to this, and an arbitrary elastic member that can obtain a desired elastic force, such as a leaf spring or a rubber material, is used. Can be used.

  Also, regarding the number of grooves 133 disposed on the shaft 130, the number of the grooves 133 in this embodiment is three, but the present invention is not limited to this. If the plane formed by connecting the center lines of the grooves 133 includes the center of rotation of the shaft 130, the number may be four or more. However, in order to avoid the complication of the configuration while obtaining the desired effect, the number is preferably 6 or less, more preferably 5 or less, and still more preferably 3.

  As described above, according to the present embodiment, the biasing means having the elastic member is partially provided between the shaft and the drive transmission member attached to the shaft. As a result, rattling between the drive transmission member and the shaft is eliminated, the drive transmission member is not decentered with respect to the shaft, and the drive transmission member can be easily attached to and detached from the shaft to improve maintenance. Can do.

Example 2
Next, another embodiment of the present invention will be described. The basic structure and operation of the drive transmission member mounting structure, drive device, and image forming apparatus of this embodiment are the same as those of the first embodiment. Therefore, in the present embodiment, elements having the same or equivalent functions and configurations as those of the first embodiment are denoted by the same reference numerals, and detailed description thereof is omitted.

  As shown in FIG. 6, in this embodiment, the shape of the pressing plate 141 of the urging unit 140 is different from that in the first embodiment.

  In the present embodiment, a tapered portion 141f whose tip 141c side is inclined toward the inner side in the radial direction of the drum shaft 130 is provided in a predetermined range from the tip 141c of the pressing plate 141. The distal end 141 c of the pressing member 141 is positioned at the distal end in the traveling direction when the drum shaft 130 is inserted into the through hole 125 of the drum flange 123. That is, in this embodiment, the pressing plate 141 has a tapered portion inclined at the tip end in the direction in which the drum shaft 130 is inserted into the through hole 125 so as to approach the rotation center of the drum shaft 130 toward the tip end side in the same direction. 141f. In the present embodiment, the tapered portion 141 f corresponds to the exposed portion 141 e exposed to the outside of the drum gear 122 in a state where the gear mounting portion 131 is inserted into the through hole 125.

  Preferably, the edge 141c1 on the outer surface 141a side of the tip of the pressing member 141 (that is, the tip of the tapered portion 141f) 141c is located on the inner side of the outer peripheral surface 131c of the gear mounting portion 131 in the radial direction of the drum shaft 130. Set to. That is, preferably, the diameter of the circumscribed circle of the edge portion 141 c 1 of the pressing member 141 is made smaller than the diameter of the outer peripheral surface 141 a of the gear mounting portion 131 of the drum shaft 130.

  Thus, when the drum shaft 130 is inserted into the through hole 125, a gap is generated between the edge portion 141c1 of the tip 141c of the pressing member 141 where the tapered portion 141f is formed and the inner peripheral surface 125a of the through hole 125. can do. Therefore, in this case, it is not necessary to press the urging unit 140 inward in the radial direction of the drum shaft 130 as in the first embodiment, and the drum shaft 130 can be inserted into the drum gear 122 more easily.

  Note that when the urging unit 140 is pressed into the retracting groove 133, the tip 141c of the tapered portion 141f can be prevented from interfering with the bottom surface 133a of the retracting groove 133. However, even if the tip 141c of the tapered portion 141f comes into contact with the bottom surface 133a of the retracting groove 133 at that time, the urging unit 140 can be retracted because the vicinity of the tapered portion 141f is bent. It only has to be like this.

  After inserting the drum shaft 130 into the drum gear 122, the same effect as in the first embodiment can be obtained.

  For example, when the drum gear 122 is removed from the drum shaft 130 during maintenance, the same procedure as in the first embodiment is performed.

  As described above, according to the present embodiment, the same effects as those of the first embodiment can be obtained, and the operation of attaching the drum gear 122 to the drum shaft 130 becomes easier.

Example 3
Next, another embodiment of the present invention will be described. The basic structure and operation of the drive transmission member mounting structure, drive device, and image forming apparatus of this embodiment are the same as those of the first embodiment. Therefore, in the present embodiment, elements having the same or equivalent functions and configurations as those of the first embodiment are denoted by the same reference numerals, and detailed description thereof is omitted.

  As shown in FIG. 7, in this embodiment, the arrangement of the urging unit 140 is different from that in the first embodiment.

  In this embodiment, the three retraction grooves 133 of the drum shaft 130 are arranged at equal intervals in the circumferential direction of the drum shaft 130. That is, an angle formed by a straight line connecting the rotation center of the drum shaft 130 and the center line in the circumferential direction of the drum shaft 130 of each bottom surface 133a of the adjacent retreat groove 133 is equal (ie, 360/3 = 120 ° interval). Set to. Then, the same urging unit 140 as in the first embodiment is arranged in the retreat groove 133 so that the urging unit 140 can be urged toward the inner peripheral surface 125 a of the through hole 125.

  After inserting the drum shaft 130 into the drum gear 122, the same effect as in the first embodiment can be obtained. In the present embodiment, the urging unit 140 is arranged as described above, so that the drum gear 122 can be more effectively prevented from being eccentric with respect to the drum shaft 130.

  For example, when the drum gear 122 is removed from the drum shaft 130 during maintenance, the same procedure as in the first embodiment is performed.

11 Photosensitive drum 110 Drum motor 120 Gear train 122 Drum gear 123 Gear flange 125 Through hole 130 Drum shaft 133 Retreat groove 140 Energizing unit 141 Press plate (press action part)
141e Exposed part 141f Taper part (exposed part)
142 Spring (Pressing member)

Claims (5)

  A rotatable shaft; and a drive transmission member attached to the shaft so as to rotate in synchronization with the shaft, the shaft including an opening into which the shaft is inserted along a rotation axis direction of the shaft, At least three grooves are formed on the outer peripheral surface of the shaft so that a plane passing through each center line includes the rotation center of the shaft, and each of the grooves is urged to be retracted inside the groove. Means is provided, the biasing means presses the inner peripheral surface of the opening, and the pressing action is longer in the direction of inserting the shaft into the opening than the inner peripheral surface of the opening. And a pressing member that is disposed between the pressing action portion and the bottom surface of the groove and presses the pressing action portion toward the inner peripheral surface of the opening. Mounting structure.   The pressure acting portion has a tapered portion inclined at a tip end in a direction in which the shaft is inserted into the opening portion so as to approach the rotation center of the shaft toward the tip end side in the same direction. Item 2. The drive transmission member mounting structure according to Item 1.   3. The drive transmission member mounting structure according to claim 1, wherein an angle formed by a straight line passing through a center line of an adjacent groove of the plurality of grooves and a rotation center of the shaft is an equal angle.   A drive source; a drive transmission member for transmitting a drive force from the drive source to the driven portion; and a rotatable shaft for transmitting the drive force transmitted to the drive transmission member to the driven portion. The drive transmission member mounting structure according to claim 1, wherein the drive transmission member mounting structure with respect to the shaft is the drive transmission member mounting structure according to claim 1.   An image forming apparatus comprising: the driving device according to claim 4; and a driven portion driven by the driving device.

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