JP2007239903A - Drive transmission mechanism and image forming device therewith - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To achieve a reduction in manufacturing cost with a simple composition besides reducing the unevenness of rotation. <P>SOLUTION: The mechanism includes idler gears 33-35 which respectively engage with a drive gear 31 and driven gear 32 and which is coaxial to one another, wherein a first and third idler gears 33, 35 have a different number of teeth from a second idler gear 34 by transformation. The first idler gear meshes with respective driving force transmission side tooth surfaces of the drive gear and driven gear. The second idler gear meshes with non-driving force transmission side tooth surfaces of the drive gear and driven gear. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a drive transmission mechanism that transmits a driving force of a driving source such as a motor to a driven object in order to drive a driven object such as a photosensitive drum in an image forming apparatus that forms an image by electrophotography. The present invention relates to an image forming apparatus including

  In an image forming apparatus that forms an image by an electrophotographic method, if the photosensitive drum has a variation in rotational speed, that is, so-called rotational unevenness, the scanning pitch in the sub-scanning direction changes. So-called banding occurs. In color image forming apparatuses, a so-called tandem configuration in which a plurality of photosensitive drums for each color of yellow, magenta, cyan, and black are arranged along an intermediate transfer belt is widely used. In this case, image quality deterioration such as uneven hue of the secondary color occurs due to uneven rotation of the photosensitive drum for each color.

  There are various causes for the uneven rotation of the photosensitive drum that causes the image quality to deteriorate. One of the causes is a drive transmission mechanism that transmits the driving force of the driving motor to the photosensitive drum. There is a gear backlash. This backlash is generally provided in order to avoid contact with the bottom of the gear train. As the rotational load of the photosensitive drum fluctuates, a vibration component is generated in the rotation on the driven side due to the backlash. This causes uneven rotation of the photosensitive drum.

Therefore, in order to reduce the uneven rotation of the photosensitive drum caused by the backlash of the gears constituting such a drive transmission mechanism, a configuration in which a so-called scissor gear is provided in which two gears are urged by a spring is known. (For example, refer to Patent Document 1). In addition, in order to stabilize the rotation of the photosensitive drum, a configuration in which a flywheel is provided on a rotation shaft in a drive transmission mechanism is known (for example, see Patent Documents 2 and 3).
Japanese Patent No. 3658369 JP-A-9-171326 JP 2000-250315 A

  However, in the configuration provided with the conventional scissor gear, one of the pair of gears that mesh with each other needs to be a scissor gear, and therefore, the gear configuration of the drive transmission mechanism that transmits the driving force of the drive motor to the photosensitive drum has multiple stages. In this case, since it is necessary to provide scissors gears corresponding to the number of stages, the structure becomes complicated, and the manufacturing cost increases due to an increase in the number of parts and the number of assembling steps.

  Further, in the configuration provided with the conventional flywheel, the effect of reducing the rotation unevenness can be improved by increasing the diameter of the flywheel, but the inertial force increases as the diameter of the flywheel increases. Therefore, it is necessary to employ a drive motor with a large output suitable for the above, and it is necessary to secure a large arrangement space.

  The present invention has been devised to solve such problems of the prior art, and its main purpose is to reduce rotation unevenness and to reduce the manufacturing cost with a simple configuration. It is an object of the present invention to provide a drive transmission mechanism configured as described above and an image forming apparatus including the drive transmission mechanism.

  The present invention has at least two idler gears that are provided coaxially with each other and are formed to have different numbers of teeth by dislocation and mesh with the driving gear and the driven gear, respectively, and one of the first idler gears is the driving gear. The driving force transmission side tooth surfaces of the gear and the driven gear are engaged with each other, and the other second idler gear is engaged with the non-driving force transmission side tooth surfaces of the driving gear and the driven gear.

  According to the present invention, it is possible to reduce uneven rotation due to vibration components caused by backlash. In addition, the combination of a plurality of idler gears provided coaxially eliminates backlash at both the meshing portions of the drive gear and the driven gear with respect to the idler gear, so a plurality of gears are provided for each meshing portion like a scissor gear. There is no need to provide it, and the configuration can be simplified and the manufacturing cost can be reduced.

  A first invention made to solve the above-described problem has at least two idler gears that are provided coaxially with each other, are formed to have different numbers of teeth by shifting, and mesh with the driving gear and the driven gear, respectively. One first idler gear meshes with each driving force transmission side tooth surface of the driving gear and the driven gear, and the other second idler gear is non-driving force transmission side of the driving gear and the driven gear. It is set as the structure engaged with the tooth surface.

  According to this, in the meshing portion of the drive gear and the idler gear, the tooth surface of the second idler gear is placed on the non-drive force transmission side tooth surface opposite to the drive force transmission side tooth surface meshing with the first idler gear in the drive gear. Contact and the backlash is removed. Similarly, at the meshing portion of the driven gear and the idler gear, the second driving force transmission side tooth surface opposite to the driving force transmission side tooth surface meshing with the first idler gear of the driven gear is set to the second side. The backlash is removed by contact of the tooth surfaces of the idler gear.

  For this reason, the rotation nonuniformity by the vibration component resulting from a backlash can be reduced. In addition, the combination of a plurality of idler gears provided coaxially eliminates backlash at both the meshing portions of the drive gear and the driven gear with respect to the idler gear, so a plurality of gears are provided for each meshing portion like a scissor gear. There is no need to provide it, and the configuration can be simplified and the manufacturing cost can be reduced.

  In this case, the first idler gear that contributes to driving force transmission may be a standard gear, and the second idler gear that contributes to backlash removal may be a shift gear with fewer teeth by forward shift. On the contrary, the second idler gear for removing backlash can be a standard gear, and the first idler gear for transmitting driving force can be a shift gear having a larger number of teeth by negative shift. Furthermore, both of the two idler gears can be used as shift gears.

  According to a second invention for solving the above-described problem, the driving gear, the driven gear, and the idler gear are helical gears, and are adapted to repeated changes in the meshing state with the driving gear or the driven gear. Thus, the meshing phase of the idler gear with respect to the drive gear or the driven gear can be set so that the transmission speed unevenness generated for each of the at least two idler gears cancels each other.

  According to this, since the transmission speed unevenness (meshing vibration) for each of the plurality of idler gears cancels each other, the rotational unevenness becomes smaller than when the drive transmission is performed with a single idler gear, and the rotational unevenness can be further reduced.

  In this case, the first and second idler gears may be configured such that the meshing phases of the driving gear and the driven gear are reversed with respect to each other. It is also possible to set the meshing phase of the idler gears so that the transmission speed irregularities between the three or more idler gears cancel each other.

  According to a third aspect of the present invention for solving the above-described problems, the driving gear, the driven gear, and the idler gear are helical gears, and the idler gears are rotatable relative to the same support shaft so as to overlap each other. It is possible to adopt a configuration in which a restricting means that is supported and restricts the movement of the idler gear in the axial direction is provided.

  According to this, since the restricting means restricts the movement of the idler gear in the axial direction against the thrust force generated in the idler gear which is a helical gear depending on the driving load, the idler gear is prevented from falling and the meshing tooth surface is twisted. Rotation unevenness caused by can be prevented.

  In this case, the restricting means may be a restricting member that is fixed so as not to be axially displaceable with respect to the support shaft of the idler gear, whereby stable rotation can be obtained even when the load fluctuation is large. Further, the restricting member provided so as to be axially displaceable with respect to the support shaft of the idler gear may be configured to be elastically pressed by the elastic member in a direction in which the plurality of idler gears are pressed against each other. Suitable when the fluctuation is not large. Further, it is preferable that the elastic force of the elastic member can be adjusted. Accordingly, even when the production accuracy of parts is low, stable rotation can be obtained by adjusting the elastic force to an appropriate magnitude.

  A fourth invention made to solve the above-described problems can be configured to have a support member that can rotatably support the idler gear and can move in a direction substantially orthogonal to the rotation axis.

  According to this, since the meshing position of the idler gear with respect to the drive gear and the driven gear can be changed by moving the support member, it is possible to adjust the meshing position to an appropriate meshing position according to the actual finished state of the gear. And uneven rotation can be further reduced.

  In this case, if the cam member is used, fine adjustment of the position of the support member can be easily performed.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

  FIG. 1 is a schematic configuration diagram showing a color image forming apparatus to which a drive transmission mechanism according to the present invention can be applied. The color image forming apparatus includes an image forming unit 1 that forms an image on a recording sheet through processes of charging, exposure, development, transfer, and fixing. The recording sheet 3 accommodated in the cassette is sequentially fed from the sheet feeding unit 2 to the image forming unit 1 through the sheet feeding path A, and the recording sheet 3 on which a required image is formed in the image forming unit 1 is the image forming unit. The paper is discharged to the paper discharge unit 4 through a paper discharge path B from 1 to the outside of the apparatus.

  The image forming unit 1 includes a plurality of process units 11 to 14 that form toner images for respective colors of yellow, magenta, cyan, and black, and the photosensitive drums 11 a to 14 a in the process units 11 to 14. A laser scanning unit (hereinafter referred to as “LSU”) 16 that scans an image surface with a light beam for exposure, and a toner for each color formed on each of the photosensitive drums 11 a to 14 a in each of the process units 11 to 14. An intermediate transfer belt (intermediate transfer member) 17 on which images are sequentially transferred and combined, and a tandem structure in which photosensitive drums 11 a to 14 a for each color are arranged along the intermediate transfer belt 17. It has become.

  In each of the process units 11 to 14, the electrostatic latent image is obtained by scanning the light beam for exposure from the LSU 16 on the image forming surfaces of the photosensitive drums 11a to 14a uniformly charged by the chargers 11b to 14b. An image is formed, and the electrostatic latent images on the respective photoconductive drums 11a to 14a are developed with the respective color toners supplied from the respective developing units 11c to 14c, and single color toner images for the respective colors are formed on the respective photoconductive drums 11a to 11a. 14a is formed on the image forming surface.

  The intermediate transfer belt 17 is supported by being wound around a driving roller 21 and a driven roller 22, and the intermediate transfer belt 17 is pressed inside the intermediate transfer belt 17 to press the toner images on the photosensitive drums 11 a to 14 a. Are provided with primary transfer rollers 24 to 27 for each color for transferring the toner image to the intermediate transfer belt 17. A secondary transfer roller 28 for transferring the toner image on the intermediate transfer belt 17 to the recording sheet 3 is disposed on the side of the end of the intermediate transfer belt 17.

  The recording sheet 3 onto which the toner image has been transferred by the secondary transfer roller 28 is conveyed to the fixing device 19 and is subjected to a process for fixing the toner image to the recording sheet 3 by heat and pressure. Thereafter, the recording sheet 3 is discharged onto the paper discharge unit 4 by the paper discharge roller 20 through the paper discharge path B.

  In the color image forming apparatus configured as described above, if the photosensitive drums 11a to 14a have uneven rotation, the scanning pitch in the sub-scanning direction changes. Therefore, uneven density in the sub-scanning direction on the image, so-called banding. Will occur. Further, when forming a color image, when the images for the respective colors are combined, the unevenness of the shades of the secondary colors occurs due to the unevenness of the density of the image for each color and the expansion and contraction of the image. Such uneven density and uneven hue are undesirable in terms of image quality, so it is important to reduce the rotational unevenness of each of the photosensitive drums 11a to 14a.

  FIG. 2 is a side view showing a drive transmission mechanism of the photosensitive drums 11a to 14a shown in FIG. 1, and a part thereof is cut away. This drive transmission mechanism transmits the driving force of the motor 37 as a drive source to the photosensitive drums 11a to 14a as driven objects to rotate the photosensitive drums 11a to 14a. It has a drive gear 32 and first to third idler gears 33 to 35 that mesh with each other and are coaxial with each other.

  The drive gear 31 is connected to a support shaft 38 that is an output shaft of the motor 37 so as not to be relatively rotatable, and the rotational torque of the motor 37 is input thereto. The driven gear 32 is connected to the support shaft 39 of the photosensitive drums 11a to 14a so as not to be relatively rotatable, and rotates the photosensitive drums 11a to 14a.

  The motor 37 is fixed to the frame 41, and holds the drive gear 31 connected to a support shaft 38 as an output shaft at a predetermined position. The support shafts 39 of the photosensitive drums 11a to 14a are supported at both ends via bearings 43 and 44 fixed to the frames 41 and 42, respectively. The idler gears 33 to 35 are loosely fitted to a support shaft 46 fixed to the frame 41 by caulking and supported so as to be relatively rotatable.

  The drive gear 31, the driven gear 32, and the idler gears 33 to 35 are helical gears, and the idler gears 33 to 35 are tilted by the thrust force generated in the idler gears 33 to 35 by the driving load, that is, the center line of the support shaft 46. In order to prevent the center lines of the idler gears 33 to 35 from being greatly inclined, the axial displacement of the idler gears 33 to 35 is restricted in a manner sandwiched between a pair of restricting members (restricting means) 48 and 49. Yes.

  The restricting members 48 and 49 are loosely fitted to the support shaft 46 and supported so as to be relatively rotatable, and the outer restricting member 48 is prevented from moving in the withdrawal direction by a retaining ring 51 locked to the support shaft 46. The side surface of the regulating member 49 is regulated by the frame 41. The restricting members 48 and 49 are set to have a relatively large axial length in order to keep the tilting of the restraining members 48 and 49 small.

  Since the idler gears 33 to 35 are adjacent to each other and have different numbers of teeth, the idler gears 33 to 35 rotate relative to each other, and in order to smoothly perform the relative rotation, the idler gears 33 to 35 are in contact with each other at the annular protrusions 53 provided on the side surfaces. ing.

  3 is a front view of the drive transmission mechanism shown in FIG. The drive gear 31 and the driven gear 32 are formed to have the number of teeth that provides a required reduction ratio. The second idler gear 34 located inside the first to third idler gears 33 to 35 is formed to have a smaller number of teeth than the first idler gear 33 by forward rotation, and the third idler gear 35 is As shown in FIG. 2, the idler gear 33 is the same as the idler gear 33, and the first and third idler gears 33 and 35 having the same number of teeth are arranged so as to sandwich the second idler gear 34 having a different number of teeth. .

  FIG. 4 is a front view showing in detail the meshing portions A and B of the drive gear 31 and the driven gear 32 and the idler gears 33 to 35 shown in FIG. In the meshing part A of the drive gear 31 and the idler gears 33 to 35, as shown in FIG. 4A, the front tooth surface (drive force transmission side tooth surface) 31a in the rotation direction of the drive gear 31 is the first and first. Driving force is transmitted from the drive gear 31 to the first and third idler gears 33 and 35 by pressing the rear tooth surfaces 33b and 35b in the rotation direction of the third idler gears 33 and 35.

  On the other hand, in the meshing part B of the driven gear 32 and the idler gears 33 to 35, as shown in FIG. 4 (B), the rotational direction front tooth surfaces 33a and 35a of the first and third idler gears 33 and 35 are The driving force is transmitted from the first and third idler gears 33 and 35 to the driven gear 32 by pressing the rear tooth surface (driving force transmitting side tooth surface) 32 b in the rotational direction of the driven gear 32.

  Further, in the meshing portion between the driven gear 32 and the idler gears 33 to 35, the front tooth surface (non-driving force transmission side tooth surface) 32 a in the rotational direction of the driven gear 32 is arranged in the rotational direction of the second idler gear 34. The side idler surface 34 b is pressed, and the second idler gear 34 rotates as the driven gear 32 rotates. Then, as shown in FIG. 4A, in the meshing portion of the drive gear 31 and the idler gears 33 to 35, the rotation direction rear tooth surface (non-driving force transmission side tooth surface) 31b of the drive gear 31 is The front tooth surface 34a in the rotational direction of the second idler gear 34 abuts.

  As described above, the combination of the first and third idler gears 33 and 35 and the second idler gear 34 substantially reduces the width of the tooth groove in which the teeth of the drive gear 31 and the driven gear 32 mesh with each other. Further, the backlash at the meshing portion between the driven gear 32 and the idler gears 33 to 35 is removed, and uneven rotation due to vibration components caused by the backlash can be reduced.

  5, 6, and 7 show the phase difference between the first and second idler gears 33 and 34 shown in FIG. 3. FIG. 5 is an example in which the difference in the number of teeth of the first and second idler gears 33 and 34 is 1, and in this case, the first and second idler gears 33 and 34 have a gear pitch of 1 in one rotation (360 degrees). One phase difference occurs, the phases of the first and second idler gears 33 and 34 coincide at one angular position of 360 degrees around the circumference, and on both sides of the reference point where there is no phase difference. Appropriate points P1 and P2 at which an angle difference corresponding to the backlash appears in the first and second idler gears 33 and 34 appear.

  Accordingly, one of the two appropriate points P1 and P2 is set as the meshing position of the drive gear 31 with respect to the first and second idler gears 33 and 34, and the other is set with respect to the first and second idler gears 33 and 34. If the engagement position of the drive gear 32 is set, the engagement without backlash is realized.

  FIG. 6 shows an example in which the difference in the number of teeth of the first and second idler gears 33 and 34 is 2. In this case, the reference point having no phase difference between the first and second idler gears 33 and 34 is shifted by 180 degrees. Appropriate points P1 to P4 at which an angular difference corresponding to the backlash occurs in the first and second idler gears 33 and 34, one on each side of the reference point.

  Here, the meshing positions of the driving gear 31 and the driven gear 32 with respect to the first and second idler gears 33 and 34 are such that the positional relationship of the teeth of the first and second idler gears 33 and 34 is opposite to each other. It is necessary to select from the appropriate points P1 to P4. For example, the appropriate points P1 and P2 or a combination of the appropriate points P2 and P3 may be selected.

  FIG. 7 shows an example in which the difference in the number of teeth of the first and second idler gears 33 and 34 is set to 3. In this case, the reference point having no phase difference between the first and second idler gears 33 and 34 is shifted by 120 degrees. Appropriate points P1 to P6 at which an angular difference corresponding to the backlash appears in the first and second idler gears 33 and 34, one on each side of the reference point.

  In this case as well, the meshing positions of the drive gear 31 and the driven gear 32 with respect to the first and second idler gears 33 and 34 are similar to each other in terms of the positional relationship between the teeth of the first and second idler gears 33 and 34. The appropriate points P1 to P4 are selected so as to be reversed. For example, the appropriate points P1 and P4, the appropriate points P2 and P3, or the combination of the appropriate points P2 and P5 may be selected.

  The appropriate points appearing on both sides of the reference point change according to the change of the meshing conditions and the like, and the arrangement conditions of the drive gear 31, the driven gear 32, and the first to third idler gears 33 to 35, etc. Is set so that an appropriate meshing can be obtained. It is also possible to finely adjust the position of the appropriate point by changing the amount of dislocation.

  FIG. 8 is a schematic diagram showing a meshing state of the drive gear 31 and idler gears 33 to 35 shown in FIG. Of the first to third idler gears 33 to 35, the first and third idler gears 33 and 35 and the second idler gear 34 have the meshing phases with respect to the drive gear 31 reversed, that is, the meshing cycle. For example, when the drive gear 31 is the tooth tip 31c at the tooth width center position of the first and third idler gears 33 and 35, the drive gear is at the tooth width center position of the second idler gear 34. 31 becomes the tooth base 31d.

In this positional relationship, the axial distance L of the tooth width center position between the first and third idler gears 33 and 35 and the second idler gear 34 is expressed by the following equation.
L = (0.5 + N) × Px
Here, Px is a pitch in the axial direction, and is obtained by the following equation using the module m, the twist angle β, and the natural number N (0, 1, 2,...).
Px = m × π / sin (β).

  In this case, the rotation unevenness caused by the difference in meshing state between the first and third idler gears 33 and 35 and the second idler gear 34 due to the tooth profile error is canceled out, thereby further reducing the rotation unevenness. Can do.

  The meshing state of the driven gear 32 and the idler gears 33 to 35 is the same as this.

  FIG. 9 is a side view showing a modification of the drive transmission mechanism shown in FIG. Here, a regulating member (regulating means) 48 provided so as to be axially displaceable with respect to the support shaft 46 of the idler gears 33 to 35 is in a direction in which the idler gears 33 to 35 are pressed against each other by a coil spring (elastic member) 61. It is being pressed in a resilient manner. Specifically, the coil spring 61 is interposed in a compressed state between the retaining ring 51 that engages with the support shaft 46 and the regulating member 48.

  In this configuration, since the coil spring 61 is appropriately elastically deformed appropriately, the contact state of the tooth surfaces of the idler gears 33 to 35 can be maintained in an appropriate state without backlash. A high rotation unevenness reduction effect can be stably obtained without being affected by the dimensional change due to.

  FIG. 10 is a side view showing a modification of the drive transmission mechanism shown in FIG. Here, a spacer 63 is interposed between the coil spring 61 and the retaining ring 51, and the elastic force is adjusted by changing the compression rate of the coil spring 61 by changing the plate thickness and the number of the spacers 63. be able to.

  In this configuration, even when the manufacturing accuracy of the parts is low, stable rotation can be obtained by adjusting the elastic force of the coil spring 61 to an appropriate magnitude.

  FIG. 11 is a front view showing a modified example of the drive transmission mechanism shown in FIG. 2, and shows a state cut along a plane orthogonal to the support shafts 38, 39, and 46. FIG. Here, the support shaft 46 of the idler gears 33 to 35 is fixed to a support plate (support member) 71, and the support plate 71 is fixed to the frame 41 by screws 72.

  The support plate 71 is provided with a screw insertion hole 73 having an inner diameter having a required play with respect to the outer diameter of the shaft portion of the screw 72. The mounting position of the support plate 71, that is, the idler gear 33 is within this play range. The mounting positions of the support shafts 46 to 35 can be moved along a plane substantially orthogonal to the support shaft 46, thereby adjusting the meshing positions of the idler gears 33 to 35 with respect to the drive gear 31 and the driven gear 32. Can do.

  Further, here, rotatable cam plates 75 and 76 are provided around the support shafts 38 and 39 of the drive gear 31 and the driven gear 32, and the cam plates 75 and 76 are fixed on the support plate 71. Abutted against the cam receiving plate 77. The cam plates 75 and 76 are eccentric cams having an eccentric arc-shaped outer contour, and the cam receiving plate 77 has an arc-shaped outer contour concentric with the support shaft 46, and is driven by rotating the cam plate 75. The distance between the shafts of the gear 31 and the idler gears 33 to 35 is increased or decreased, and the cam plate 76 is rotated so that the distance between the driven gear 32 and the idler gears 33 to 35 is increased or decreased. Fine adjustment of the meshing position of the idler gears 33 to 35 with respect to the gear 32 can be easily performed.

  The example having three idler gears has been described above, but a configuration with two idler gears or four or more idler gears is also possible. In addition, although some of the plurality of idler gears, here, the first and third idler gears 33 and 35 have the same number of teeth, these idler gears may have different numbers of teeth.

  Here, an example in which the driving gear 31, the driven gear 32, and the idler gears 33 to 35 are helical gears has been described, but these gears may be configured as spur gears.

  Also, here, an example is shown in which the first to third idler gears 33 to 35 are brought into contact with each other. However, high friction members and elastic members having wear resistance are interposed between the idler gears 33 to 35. In this case, the rotation unevenness can be further reduced by the vibration damping effect of the high friction member or the elastic member.

  A drive transmission mechanism and an image forming apparatus including the same according to the present invention are effective in reducing rotation unevenness and reducing the manufacturing cost with a simple configuration, and in an image forming apparatus that forms an image by an electrophotographic method. A drive transmission mechanism that transmits a driving force of a driving source such as a motor to a driven object in order to drive a driven object such as a photosensitive drum, and an image forming apparatus including the drive transmission mechanism, such as a printer, a copier, a facsimile machine, and a multifunction machine It is useful as such.

1 is a schematic configuration diagram showing a color image forming apparatus to which a drive transmission mechanism according to the present invention is applicable. FIG. 2 is a side view showing a drive transmission mechanism of the photosensitive drum shown in FIG. Front view of the drive transmission mechanism shown in FIG. FIG. 3 is a front view showing in detail the meshing portions A and B of the drive gear and the driven gear and the idler gear shown in FIG. The figure which shows the phase difference of the 1st and 2nd idler gear shown in FIG. The figure which shows the phase difference of the 1st and 2nd idler gear shown in FIG. The figure which shows the phase difference of the 1st and 2nd idler gear shown in FIG. Schematic diagram showing the meshing state of the drive gear and idler gear shown in FIG. The side view which shows the modification of the drive transmission mechanism shown in FIG. The side view which shows the modification of the drive transmission mechanism shown in FIG. The front view which shows the modification of the drive transmission mechanism shown in FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Image formation part 11a-14a Photosensitive drum 31 Drive gear 31a Rotational direction front side tooth surface (Driving force transmission side tooth surface)
31b Rotational direction rear tooth surface (non-driving force transmission tooth surface)
32 Driven gear 32a Front tooth surface in rotation direction (non-driving force transmission tooth surface)
32b Rotational direction rear tooth surface (driving force transmission side tooth surface)
33-35 idler gear 48/49 regulating member (regulating means)
71 Support plate (support member)

Claims (5)

Having at least two idler gears provided coaxially with each other and formed in different numbers of teeth by dislocation and meshing with the driving gear and the driven gear, respectively,
One first idler gear meshes with each driving force transmission side tooth surface of the driving gear and the driven gear, and the other second idler gear is non-driving force transmission side of the driving gear and the driven gear. A drive transmission mechanism characterized by engaging with a tooth surface. The driving gear, driven gear and idler gear are helical gears;
The idler gear with respect to the drive gear or the driven gear is arranged so that the transmission speed unevenness generated for each of the at least two idler gears cancels each other in response to repeated changes in the meshing state with the drive gear or the driven gear. The drive transmission mechanism according to claim 1, wherein a meshing phase is set. The driving gear, driven gear and idler gear are helical gears;
2. The drive transmission mechanism according to claim 1, wherein the idler gear is supported by the same support shaft so as to be rotatable relative to each other so as to overlap each other, and a restriction means for restricting movement of the idler gear in the axial direction is provided. .   The drive transmission mechanism according to claim 1, further comprising a support member that rotatably supports the idler gear and that is movable in a direction substantially orthogonal to a rotation axis thereof.   An image forming apparatus comprising the drive transmission mechanism according to claim 1.

Images