JP6559491B2 - Drive transmission mechanism and image forming apparatus having the same - Google Patents

Description

  The present invention relates to a drive transmission mechanism that transmits a rotational driving force from a driving side to a driven side, and an image forming apparatus such as a copying machine, a multifunction machine, a printer, and a facsimile machine including the driving transmission mechanism.

  As a drive transmission mechanism that transmits rotational driving force from the drive side to the driven side (driven side), it has an external gear and an internal gear, and is driven to rotate from the drive side to the driven side by meshing between the external gear and the internal gear. Some are configured to transmit force.

  Such a drive transmission mechanism is provided, for example, in an image forming apparatus (specifically, a photosensitive drum) from an internal gear or an external gear provided in a driving device including a driving motor on a driving side in an image forming apparatus. It is applied as a drive transmission mechanism that transmits a rotational driving force to the external gear or the internal gear.

  However, in the conventional configuration of the drive transmission mechanism, if the other rotation shaft is inclined with respect to one of the drive-side rotation shaft and the driven-side rotation shaft, the teeth of the external gear and the internal gear are mutually engaged. Rotational transmission unevenness occurs due to the interference of the portions.

  In particular, in the case where such a drive transmission mechanism is applied to a drive transmission mechanism from the drive device of the image forming apparatus to the image carrier, the rotational drive transmission from the drive device to the image carrier is caused by minute rotation transmission unevenness. However, periodic unevenness corresponding to rotational transmission unevenness may occur in the formed image.

  In this regard, Patent Document 1 discloses that the external gear is negatively displaced and the internal gear is positively displaced so that the cross-sectional shape of the teeth along the direction orthogonal to the rotational axis direction is constant in the rotational axis direction. A drive transmission mechanism is disclosed.

JP 2008-58360 A

  However, as in the drive transmission mechanism described in Patent Document 1, even if the external gear is negatively shifted or the internal gear is positively shifted, the cross-sectional shape of the teeth along the direction orthogonal to the rotation axis direction is Since it is constant in the rotation axis direction, it is not possible to sufficiently prevent rotation transmission unevenness due to interference between the tooth portions of the external gear and the internal gear.

  In view of this, the present invention provides the rotation by the interference of the tooth portions of the external gear and the internal gear even when the other rotary shaft is inclined with respect to one of the driven rotary shaft and the driven rotary shaft. An object of the present invention is to provide a drive transmission mechanism that can effectively prevent transmission unevenness and an image forming apparatus including the drive transmission mechanism.

In order to solve the above problems, the present invention provides a drive transmission mechanism according to the following first to third aspects and an image forming apparatus according to the first to third aspects .

(1) Drive transmission mechanism according to the first aspect A drive transmission mechanism according to the first aspect of the present invention is a drive transmission mechanism that transmits a rotational driving force from a drive side to a driven side, and includes an external gear, an internal gear, And is configured to transmit the rotational driving force from the driving side to the driven side by meshing between the external gear and the internal gear, and the external gear extends from the base end side to the tip end side in the rotation axis direction. Minus dislocation so that the teeth gradually become smaller, the absolute value of the dislocation amount per unit distance in the rotation axis direction of the outer gear is constant or substantially constant, and the unit distance of the outer gear in the rotation axis direction The absolute value of the constant or substantially constant dislocation amount is increased stepwise from the proximal end side to the distal end side .

(2) Second Mode Drive Transmission Mechanism A second mode drive transmission mechanism according to the present invention is a drive transmission mechanism that transmits a rotational driving force from a drive side to a driven side, and includes an external gear, an internal gear, The rotational drive force is transmitted from the drive side to the driven side by meshing between the external gear and the internal gear, and the internal gear extends from the distal end side to the proximal end side in the rotational axis direction. The gear shifts so that the teeth gradually become smaller, the absolute value of the shift amount per unit distance in the rotation axis direction of the internal gear is constant or substantially constant, and the unit distance of the internal gear in the rotation axis direction The absolute value of the constant or substantially constant dislocation amount is increased stepwise from the distal end side to the proximal end side .

(3) Third Mode Drive Transmission Mechanism A third mode drive transmission mechanism according to the present invention is a drive transmission mechanism that transmits rotational driving force from the drive side to the driven side, and includes an external gear, an internal gear, And is configured to transmit the rotational driving force from the driving side to the driven side by meshing between the external gear and the internal gear, and the external gear extends from the base end side to the tip end side in the rotation axis direction. The internal gear is negatively displaced so that the teeth gradually become smaller, and the internal gear is positively displaced so that the teeth gradually become smaller from the distal end side to the proximal end side in the rotation axis direction.

(4) Image Forming Apparatus According to First Aspect The image forming apparatus according to the first aspect of the present invention includes any one drive transmission mechanism from the first aspect to the third aspect according to the present invention. And
(5) Image forming apparatus according to second aspect
An image forming apparatus according to a second aspect of the present invention is a drive transmission mechanism that transmits a rotational driving force from a driving side to a driven side, and includes an external gear and an internal gear, and the external gear and the internal gear. The rotational gear is configured to transmit the rotational driving force from the driving side to the driven side by meshing with the external gear, and the external gear is negatively displaced so that the teeth gradually become smaller from the proximal side to the distal side in the rotational axis direction. The drive transmission mechanism is provided.
(6) Image forming apparatus according to the third aspect
An image forming apparatus according to a third aspect of the present invention is a drive transmission mechanism that transmits a rotational driving force from a drive side to a driven side, and includes an external gear and an internal gear, and the external gear and the internal gear. The rotational gear is configured to transmit the rotational driving force from the driving side to the driven side by meshing with the internal gear, and the internal gear is positively displaced so that the teeth gradually become smaller from the distal end side to the proximal end side in the rotational axis direction. The drive transmission mechanism is provided.

In the drive transmission mechanism of the third aspect Ru engages the present invention, the absolute value of the dislocation amount per unit distance in the rotation axis direction of the external gear can be exemplified embodiment is constant or substantially constant.

Step according to the drive transmission mechanism of the third aspect Ru engages the present invention, the absolute value of the constant or nearly constant dislocations per unit distance in the rotation axis direction of the external gear is going to the distal side from the proximal-side The aspect which is becoming large can be illustrated.

In the drive transmission mechanism of the third aspect Ru engages the present invention, the absolute value of the dislocation amount per unit distance in the rotation axis direction of the internal gear can be exemplified embodiment is constant or substantially constant.

Step according to the drive transmission mechanism of the engaging Ru third aspect the present invention, the absolute value of the constant or nearly constant dislocations per unit distance in the rotation axis direction of the internal gear is going to the proximal side from the distal end The aspect which is becoming large can be illustrated.

  According to the present invention, even if the other rotating shaft is inclined with respect to one of the driving-side rotating shaft and the driven-side rotating shaft, the rotation is transmitted by the interference between the tooth portions of the external gear and the internal gear. Unevenness can be effectively prevented.

1 is a schematic cross-sectional view showing a main part of an image forming apparatus according to the present embodiment. FIG. 3 is a schematic perspective view of the photoconductor unit viewed from the upper right side on the back side. FIG. 4 is a schematic perspective view of the photosensitive unit as viewed from the upper left oblique side on the front side. FIG. 3 is a schematic plan view of a state in which a photosensitive unit is connected to a driving device in an image forming apparatus main body via a drive transmission mechanism, as viewed from above. In the conventional structure of a drive transmission mechanism, it is the side view which looked at the external gear and internal gear of the state which mutually meshed | engaged from the one side of the width direction. It is the schematic perspective view which looked at the external gear in the conventional structure of a drive transmission mechanism from the front end side. It is the schematic perspective view which looked at the internal gear in the conventional structure of a drive transmission mechanism from the front end side. It is a schematic sectional drawing which shows the meshing state of the external gear and internal gear in the conventional structure of a drive transmission mechanism. It is the schematic perspective view which looked at the external gear in the drive transmission mechanism concerning a 1st embodiment from the tip side. It is a schematic sectional drawing which shows the meshing state of the external gear and the internal gear in the drive transmission mechanism which concerns on 1st Embodiment. It is the schematic perspective view which looked at the internal gear in the drive transmission mechanism concerning a 2nd embodiment from the tip side. It is a schematic sectional drawing which shows the meshing state of the external gear and the internal gear in the drive transmission mechanism which concerns on 2nd Embodiment. It is a schematic sectional drawing which shows the meshing state of the external gear and the internal gear in the drive transmission mechanism which concerns on 3rd Embodiment. It is a schematic sectional drawing which shows the other example of an external gear and an internal gear, Comprising: (a) is a figure which shows an external gear, (b) is a figure which shows an internal gear. It is a schematic sectional drawing which shows the other example of an external gear and an internal gear, Comprising: (a) is a figure which shows an external gear, (b) is a figure which shows an internal gear.

  Embodiments according to the present invention will be described below with reference to the drawings.

  FIG. 1 is a schematic cross-sectional view showing a main part of an image forming apparatus 100 according to the present embodiment. In FIG. 1 and FIGS. 2 to 15 described later, the symbol X indicates the left-right direction. Reference symbol Y indicates the width direction (depth direction). Reference symbol Z indicates a vertical direction (specifically, a height direction).

  The image forming apparatus 100 is an electrophotographic image forming apparatus and includes an image forming apparatus main body 110. The image forming apparatus 100 forms an image on a recording sheet P such as a recording sheet by the image forming unit 111 in the image forming apparatus main body 110 based on the image data.

  The image forming apparatus 100 may be a monochrome image forming apparatus, or a configuration in which a plurality of electrostatic latent image carriers are juxtaposed in a predetermined direction (specifically, the left-right direction X), so-called tandem. The color image forming apparatus may be an intermediate transfer type color composite machine capable of forming a full color image, or may be another color image forming apparatus.

  The image forming unit 111 includes a photosensitive member 11 (specifically, a photosensitive drum) that acts as an image carrier, a charging device 12 (specifically, a charger), an exposure device 13, a developing device 14, a transfer device 15, and a cleaning device. A device 16 and a fixing device (not shown) are provided. Here, the photoconductor unit 10 includes the photoconductor 11, the charging device 12, and the cleaning device 16.

  In the image forming unit 111, the surface of the photoconductor 11 is charged by the charging device 12, the image is exposed to the charged area, an electrostatic latent image is formed by the exposure device 13, and the electrostatic latent image is developed by the developing device 14. The image is visualized (developed) as an image, the visualized toner image is transferred to the recording sheet P by the transfer device 15, and the toner image is further transferred to the recording sheet P to which the toner image is transferred. (Omitted).

  That is, the charging device 12 uniformly charges the surface of the photoconductor 11 to a predetermined potential. The exposure device 13 exposes the surface of the photoconductor 11 uniformly charged by the charging device 12 to form an electrostatic latent image on the surface of the photoconductor 11. The developing device 14 develops the electrostatic latent image on the surface of the photoconductor 11 formed by the exposure device 13 to form a toner image on the surface of the photoconductor 11. The transfer device 15 transfers the toner image formed on the surface of the photoreceptor 11 onto the recording sheet P. The cleaning device 16 removes and collects residual toner on the surface of the photoconductor 11 that remains without being transferred to the recording sheet P. The fixing device (not shown) heats and presses the recording sheet P to which the toner image is transferred, and fixes the toner image to the recording sheet P.

(About drive transmission mechanism)
Next, the drive transmission mechanism 20 provided in the image forming apparatus 100 will be described below with reference to FIGS.

  FIG. 2 is a schematic perspective view of the photoconductor unit 10 as viewed from the upper right side on the back side. FIG. 3 is a schematic perspective view of the photoconductor unit 10 as viewed from the upper left side on the front side. FIG. 4 is a schematic plan view of a state in which the photosensitive unit 10 is coupled to the driving device 30 in the image forming apparatus main body 110 via the drive transmission mechanism 20 as viewed from above. In FIG. 4, the charging device 12, the cleaning device 16, and the like are not shown.

  The photoreceptor unit 10 further includes a front side plate 101 and a rear side plate 102. The front side plate 101 and the rear side plate 102 are connected by a connecting member (not shown) with the photoreceptor 11 in between.

  The front plate 101 is provided along both the left-right direction X and the up-down direction Z on the front side of the photoconductor unit main body 10a, and the driven-side (driven-side) rotation shaft 11a (specifically, the photoconductor 11). The front side of the rotating shaft is supported rotatably. A front positioning pin 101 a is provided on the front surface of the front plate 101. The front positioning pin 101a protrudes from the front surface of the front plate 101 along the width direction Y on one side Y1 (specifically, the front side) in the width direction Y.

  The rear plate 102 is provided on the rear side of the photoconductor unit main body 10a along both the left-right direction X and the up-down direction Z, and rotatably supports the rear side of the driven-side rotating shaft 11a. . A rear positioning pin 102 a is provided on the rear surface of the rear plate 102. The rear positioning pin 102a is located at a position different from the front positioning pin 101a in both the horizontal direction X and the vertical direction Z from the rear surface of the rear plate 102 along the width direction Y to the other side Y2 of the width direction Y (specifically In reality, it protrudes from the rear side.

  The image forming apparatus main body 110 includes a front frame 110a (see FIG. 4), an opening / closing lid 110b (see FIG. 4), and a rear frame 110c (see FIG. 4).

  The front frame 110 a is provided along both the horizontal direction X and the vertical direction Z on the front side of the image forming apparatus main body 110. The photoreceptor unit 10 is detachably attached to the image forming apparatus main body 110. An attachment / detachment hole 110a1 is provided in the front frame 110a for mounting the photosensitive unit 10 from one side Y1 (operation side) in the width direction Y to the other side Y2 and detaching from the other side Y2 in the width direction Y to the one side Y1. Is provided.

  The opening / closing lid 110b is fixed to the front frame 110a in a state where it can be opened and closed with respect to the front frame 110a and closed on the front side of the front frame 110a. The opening / closing lid 110b is provided with a front positioning hole 110b1 (see FIG. 4) that penetrates in the width direction Y and passes through the front positioning pin 101a in the photoreceptor unit 10. The front positioning hole 110b1 is inserted through the front positioning pin 101a in the photoconductor unit 10 so that the positions of the photoconductor unit 10 (and thus the photoconductor 11) in the left-right direction X and the up-down direction Z are located on the front side of the image forming apparatus main body 110. It can be positioned.

  The rear frame 110 c is provided along both the left-right direction X and the up-down direction Z on the rear side of the image forming apparatus main body 110. The rear frame 110c is provided with a rear positioning hole 110c1 (see FIG. 4) that penetrates in the width direction Y and passes through the rear positioning pin 102a in the photoreceptor unit 10. The rear positioning hole 110c1 is inserted through the rear positioning pin 102a in the photoconductor unit 10 so that the left and right directions X and Z in the left and right directions of the photoconductor unit 10 (and hence the photoconductor 11) on the rear side of the image forming apparatus main body 110 are inserted. Can be positioned.

  The movement of the photoconductor unit 10 in the width direction Y to the one side Y1 can be regulated by a front side regulating member 110b2 (see FIG. 4) provided on the opening / closing lid 110b. Further, the movement of the photoconductor unit 10 in the width direction Y to the other side Y2 can be restricted by a rear side regulating member 110c2 (see FIG. 4) provided on the rear frame 110c.

  As shown in FIG. 4, the image forming apparatus main body 110 includes a drive transmission mechanism 20 that transmits a rotational driving force from a driving side to a driven side (driven side), and a driving device 30 that includes a driving motor 31 on the driving side. It has more.

  In addition to the drive motor 31, the drive device 30 drives the front side plate 30 a, the rear side plate 30 b, the left side plate 30 c, the right side plate 30 d, the drive side rotary shaft 32, and the rotational drive force from the drive motor 31. And a drive transmission portion 33 that transmits to the rotary shaft 32 on the side.

  The front plate 30a is supported on the rear frame 110c at a predetermined interval by a support member (not shown) along both the left-right direction X and the up-down direction Z.

  The rear side plate 30b is fixed to the front side plate 30a through the left side plate 30c and the right side plate 30d along both the horizontal direction X and the vertical direction Z.

  The drive motor 31 is fixed to the surface on the one side Y1 in the width direction Y of the rear plate 30b so that the rotation shaft 31a faces the one side Y1 in the width direction Y.

  The drive-side rotary shaft 32 is provided so as to be rotatable about an axis along the width direction Y with respect to the front plate 30a via a bearing 32a.

  In this example, the drive transmission unit 33 is a gear train that includes a motor gear 33a, a drive gear 33b, and an intermediate gear 33c.

  The motor gear 33 a is fixed to the rotation shaft 31 a of the drive motor 31. The drive gear 33b is fixed to the rotary shaft 32 on the drive side. The intermediate gear 33c is rotatably provided around an axis along the width direction Y via a bearing 34a with respect to a support shaft 34 fixed to the front plate 30a so as to mesh with both the motor gear 33a and the drive gear 33b. It has been.

  The drive transmission mechanism 20 includes an external gear 21 (see FIGS. 4 and 5) and an internal gear 22 (see FIG. 4), and is engaged with the external gear 21 and the internal gear 22 (in this example, a driving device). 30), the rotational driving force is transmitted from the driven side to the driven side (photosensitive member 11 in this example). The drive transmission mechanism 20 is a so-called gear shaft coupling (gear coupling).

  Specifically, the external gear 21 is fixed to a portion protruding from the rear plate 102 in the photosensitive unit 10 of the driven-side rotating shaft 11a to the other side Y2 in the width direction Y. The internal gear 22 is fixed to a portion protruding from the front plate 30a of the driving device 30 of the driving side rotating shaft 11a to the one side Y1 in the width direction Y. In this example, the external gear 21 constituting the drive transmission mechanism 20 is fixed to the driven-side rotary shaft 11a, and the internal gear 22 constituting the drive transmission mechanism 20 is fixed to the drive-side rotary shaft 32. However, the internal gear 22 constituting the drive transmission mechanism 20 may be fixed to the driven-side rotary shaft 11a, and the external gear 21 constituting the drive transmission mechanism 20 may be fixed to the drive-side rotary shaft 32. .

  In the image forming apparatus 100 described above, when the rotational driving force is transmitted from the driving device 30 to the photoconductor 11, when electric power is supplied to the driving motor 31, the rotating shaft 32 is rotationally driven to rotate the motor gear 33a. Accordingly, the drive gear 33b rotates through the intermediate gear 33c, and the drive-side rotating shaft 32 further rotates. Then, in the drive transmission mechanism 20, the internal gear 22 and the external gear 21 that are meshed with each other rotate. As a result, the rotational driving force from the driving motor 31 on the driving side can be transmitted to the driven photoreceptor 11 via the driving transmission unit 33 via the internal gear 22 and the external gear 21 in the driving transmission mechanism 20. .

  By the way, in the conventional configuration of the drive transmission mechanism 20, when the other rotation shaft is inclined with respect to one rotation shaft of the drive-side rotation shaft 32 and the driven-side rotation shaft 11a, the outer gear 21 and the inner gear. Rotation transmission unevenness occurs due to interference between the 22 teeth 21a and 22a (see FIG. 4).

  FIG. 5 is a side view of the external gear 21 and the internal gear 22 that are in mesh with each other, as viewed from one side Y1 in the width direction Y, in the conventional configuration of the drive transmission mechanism 20. FIG. 6 is a schematic perspective view of the external gear 21 in the conventional configuration of the drive transmission mechanism 20 as viewed from the front end side. FIG. 7 is a schematic perspective view of the internal gear 22 in the conventional configuration of the drive transmission mechanism 20 as viewed from the front end side. FIG. 8 is a schematic cross-sectional view showing the meshed state of the external gear 21 and the internal gear 22 in the conventional configuration of the drive transmission mechanism 20.

  In the external gear 21 and the internal gear 22, the cross-sectional shapes of the teeth 21a and 22a along the direction orthogonal to the rotation axis direction (the width direction Y in this example) are constant in the rotation axis direction. Specifically, the teeth 21a and 22a of the external gear 21 and the internal gear 22 are spur teeth. The tooth shapes of the external gear 21 and the internal gear 22 are involute tooth shapes. The tooth forms of the external gear 21 and the internal gear 22 are standardized tooth forms.

  In the conventional configuration of the drive transmission mechanism 20, for example, even if the driven-side photoconductor 11 is positioned on the image forming apparatus main body 110, the driven-side rotating shaft 11 a and the driving-side rotating shaft 11 a and the driving-side rotating shaft 11 a due to dimensional variations of components. Of the rotating shafts 32, the other rotating shaft (particularly the driven rotating shaft 11a) may be inclined with respect to one rotating shaft (see the right side of FIG. 8). Then, since the external gear 21 and the internal gear 22 have the same cross-sectional shape of the teeth 21a and 22a along the direction orthogonal to the rotational axis direction (the width direction Y in this example), the external gear 21 and the internal gear 22 are constant in the rotational axis direction. The teeth 21a and 22a of the gear 21 and the internal gear 22 interfere with each other (see α shown in the right side of FIG. 8) (particularly, the crest 21a1 (see FIG. 6) of the tooth 21a of the external gear 21 and the internal gear). 22 and the valley 22a2 (see FIG. 7) of the tooth 22a interferes, or / and the valley 21a2 (see FIG. 6) of the tooth 21a of the external gear 21 and the peak 22a1 (see FIG. 6) of the tooth 22a of the internal gear 22. 7)), the rotation transmission unevenness occurs, and as a result, a periodic unevenness corresponding to the rotation transmission unevenness may occur in the formed image.

(First embodiment)
In this regard, the drive transmission mechanism 20A according to the first embodiment has the following configuration.

  FIG. 9 is a schematic perspective view of the external gear 21A in the drive transmission mechanism 20A according to the first embodiment viewed from the distal end side E2. FIG. 10 is a schematic cross-sectional view showing the meshed state of the external gear 21A and the internal gear 22 in the drive transmission mechanism 20A according to the first embodiment. In FIGS. 9 and 10 and FIGS. 11 to 15 to be described later, in order to make the description easy to understand, they are exaggerated from the actual ones.

  In the first embodiment, members that are substantially the same as conventional members are assigned the same reference numerals, and descriptions thereof are omitted.

  As shown in FIGS. 9 and 10, the external gear 21 </ b> A has a distal end side E <b> 2 (internal gear 22) from the proximal end side E <b> 1 (side end side where the rotational shaft 11 a is provided) in the rotational axis direction (the width direction Y in this example). The tooth 21aA is negatively displaced so that the tooth 21aA gradually becomes smaller toward the side end meshing with the tooth. The teeth 21aA of the external gear 21A become thinner from the proximal end E1 to the distal end E2 (see FIG. 9).

  Specifically, the external gear 21A undergoes a negative shift so that the absolute value of the shift amount gradually increases from the proximal end E1 to the distal end E2. The shape of the tooth 21aA of the external gear 21A is a standardized tooth profile on the base end side E1, and gradually decreases in a similar shape or a substantially similar shape from the base end side E1 to the front end side E2.

  In this example, the external gear 21A is configured such that the absolute value of the dislocation amount per unit distance in the rotation axis direction (in this example, the width direction Y) is constant or substantially constant. That is, in the external gear 21A, the outer shape of the tooth 21aA (the cross-sectional shape along the direction orthogonal to the rotation axis direction) decreases linearly from the proximal end E1 to the distal end E2.

  Specifically, in the external gear 21A in which the teeth 21aA are spur teeth and the tooth profile is an involute tooth profile, the absolute value of the shift amount is gradually increased from the base end side E1 to the front end side E2 in the negative shift. Is formed.

(Second Embodiment)
The drive transmission mechanism 20B according to the second embodiment has the following configuration.

  FIG. 11 is a schematic perspective view of the internal gear 22B in the drive transmission mechanism 20B according to the second embodiment as viewed from the distal end side E4 side. FIG. 12 is a schematic cross-sectional view showing the meshed state of the external gear 21 and the internal gear 22B in the drive transmission mechanism 20B according to the second embodiment.

  In the second embodiment, members that are substantially the same as conventional members are assigned the same reference numerals, and descriptions thereof are omitted.

  As shown in FIGS. 11 and 12, the internal gear 22B has a base end side E3 (the rotation shaft 32 is connected to the external gear 21) from the front end side E4 (the side end side meshing with the external gear 21) in the rotation axis direction (the width direction Y in this example). Positive dislocation is performed so that the teeth 22aB gradually become smaller toward the side end provided). The teeth 22aB of the internal gear 22B become thinner from the distal end side E4 to the proximal end side E3 (see FIG. 11).

  Specifically, the internal gear 22B is positively displaced so that the absolute value of the amount of dislocation gradually increases from the distal end side E4 to the proximal end side E3. The shape of the teeth 22aB of the internal gear 22B is a standardized tooth profile at the distal end side E4, and gradually decreases in a similar or substantially similar shape from the distal end side E4 to the proximal end side E3.

  In this example, the internal gear 22B is configured such that the absolute value of the dislocation amount per unit distance in the rotation axis direction (in this example, the width direction Y) is constant or substantially constant. That is, in the internal gear 22B, the outer shape (cross-sectional shape along the direction orthogonal to the rotation axis direction) of the teeth 22aB is linearly reduced from the distal end side E4 to the proximal end side E3.

  Specifically, in the internal gear 22B in which the tooth 22aB is a flat tooth and the tooth shape is an involute tooth shape, the absolute value of the dislocation amount is gradually increased from the distal end side E4 to the proximal end side E3 when performing positive displacement. Is formed.

(Third embodiment)
Further, the drive transmission mechanism 20C according to the third embodiment has the following configuration.

  FIG. 13 is a schematic cross-sectional view showing the meshed state of the external gear 21A and the internal gear 22B in the drive transmission mechanism 20C according to the third embodiment.

  In the third embodiment, substantially the same members as those in the first embodiment and the second embodiment are denoted by the same reference numerals.

  As shown in FIG. 13, the external gear 21A is negatively displaced so that the teeth 21aA gradually decrease from the base end side E1 to the front end side E2 in the rotation axis direction (in this example, the width direction Y). The teeth 21aA of the external gear 21A become thinner from the proximal end E1 to the distal end E2 (see FIG. 9).

  Specifically, the external gear 21A undergoes a negative shift so that the absolute value of the shift amount gradually increases from the proximal end E1 to the distal end E2.

  In this example, the external gear 21A is configured such that the absolute value of the dislocation amount per unit distance in the rotation axis direction (in this example, the width direction Y) is constant or substantially constant.

  Specifically, in the external gear 21A in which the teeth 21aA are spur teeth and the tooth profile is an involute tooth profile, the absolute value of the shift amount is gradually increased from the base end side E1 to the front end side E2 in the negative shift. Is formed.

  Further, the internal gear 22B is positively displaced so that the teeth 22aB gradually decrease from the distal end side E4 to the proximal end side E3 in the rotation axis direction (in this example, the width direction Y). The teeth 22aB of the internal gear 22B become thinner from the distal end side E4 to the proximal end side E3 (see FIG. 11).

  Specifically, the internal gear 22B is positively displaced so that the absolute value of the amount of dislocation gradually increases from the distal end side E4 to the proximal end side E3.

  In this example, the internal gear 22B is configured such that the absolute value of the dislocation amount per unit distance in the rotation axis direction (in this example, the width direction Y) is constant or substantially constant.

  Specifically, in the internal gear 22B in which the tooth 22aB is a flat tooth and the tooth shape is an involute tooth shape, the absolute value of the dislocation amount is gradually increased from the distal end side E4 to the proximal end side E3 when performing positive displacement. Is formed.

(Other examples of external gear and internal gear)
FIG. 14 is a schematic cross-sectional view showing another example of the external gear 21A and the internal gear 22B. FIG. 14A shows the external gear 21A, and FIG. 14B shows the internal gear 22B.

  The external gear 21A shown in FIG. 14A can be suitably used for the external gear 21A of the first embodiment and the third embodiment.

  As shown in FIG. 14 (a), the external gear 21A has an absolute value of a constant or substantially constant dislocation amount per unit distance in the rotation axis direction (in this example, the width direction Y) from the base end side E1 to the front end side E2. It is configured to increase in steps as you go.

  Specifically, a plurality (two in this example) of dislocation regions β1 and β2 having different absolute values of constant or substantially constant dislocation amounts per unit distance in the rotation axis direction (in this example, the width direction Y) of the external gear 21A. Is present. That is, the external gear 21A has one or a plurality of change points (in this example, one change point Q1) at which the gradient of the absolute value of the dislocation amount per unit distance changes.

  The slope of the absolute value of the dislocation amount per unit distance in the plurality of dislocation regions β1 and β2 increases from the proximal end E1 toward the distal end E2.

  The internal gear 22B shown in FIG. 14B can be suitably used for the internal gear 22B of the second embodiment and the third embodiment.

  As shown in FIG. 14B, the internal gear 22B has an absolute value of a constant or substantially constant dislocation amount per unit distance in the rotation axis direction (in this example, the width direction Y) from the distal end side E4 to the proximal end side E3. It is configured to increase in steps as you go.

  Specifically, a plurality (two in this example) of dislocation regions γ1, γ2 having different absolute values of constant or substantially constant dislocation amounts per unit distance in the rotation axis direction (in this example, width direction Y) of the internal gear 22B. Is present. That is, the internal gear 22B has one or a plurality of change points (in this example, one change point Q2) where the gradient of the absolute value of the dislocation amount per unit distance changes.

  The slope of the absolute value of the dislocation amount per unit distance in the plurality of dislocation regions γ1 and γ2 increases from the distal end side E4 to the proximal end side E3.

(Other examples of external gear and internal gear)
FIG. 15 is a schematic cross-sectional view showing still another example of the external gear 21A and the internal gear 22B. 15A shows the external gear 21A, and FIG. 15B shows the internal gear 22B.

  The external gear 21A shown in FIG. 15 (a) can be suitably used for the external gear 21A of the first and third embodiments.

  As shown in FIG. 15A, in the external gear 21A, the absolute value of the dislocation amount per unit distance in the rotation axis direction (in this example, the width direction Y) gradually increases as it goes from the proximal end E1 to the distal end E2. It is comprised so that it may become. That is, in the external gear 21A, the outer shape of the tooth 21aA (the cross-sectional shape along the direction orthogonal to the rotational axis direction) becomes smaller in a curve as it goes from the proximal end E1 to the distal end E2.

  The internal gear 22B shown in FIG. 15B can be suitably used for the internal gear 22B of the second embodiment and the third embodiment.

  As shown in FIG. 15B, in the internal gear 22B, the absolute value of the dislocation amount per unit distance in the rotation axis direction (in this example, the width direction Y) gradually increases as it goes from the distal end side E4 to the proximal end side E3. It is comprised so that it may become. That is, in the internal gear 22B, the outer shape of the tooth 22aB (the cross-sectional shape along the direction orthogonal to the rotation axis direction) decreases in a curve as it goes from the distal end side E4 to the proximal end side E3.

(About this embodiment)
According to the drive transmission mechanism 20A according to the first embodiment, the external gear 21A is negatively displaced so that the teeth 21aA gradually decrease from the proximal end E1 to the distal end E2 in the rotation axis direction (in this example, the width direction Y). Therefore, in the rotation axis direction (the width direction Y in this example), for example, the shape of the tooth 21aA of the external gear 21A is a standardized tooth profile on the base end side E1, and is similar from the base end side E1 to the front end side E2. It can be gradually reduced in shape or substantially similar. Therefore, even if the other rotating shaft is inclined with respect to one rotating shaft among the driving-side rotating shaft 32 and the driven-side rotating shaft 11a, the teeth 21aA and 22a of the external gear 21A and the internal gear 22 are mutually connected. Interference can be suppressed, thereby making it possible to effectively prevent rotation transmission unevenness.

  According to the drive transmission mechanism 20B according to the second embodiment, the internal gear 22B is positively displaced so that the teeth 22aB gradually decrease from the distal end side E4 to the proximal end side E3 in the rotation axis direction (in this example, the width direction Y). Therefore, in the rotational axis direction (the width direction Y in this example), for example, the shape of the tooth 22aB of the internal gear 22B is a standardized tooth profile on the distal end side E4, and is similar from the distal end side E4 to the proximal end side E3. Alternatively, it can be gradually reduced in a substantially similar shape. Therefore, even if the other rotating shaft is inclined with respect to one rotating shaft of the driving-side rotating shaft 32 and the driven-side rotating shaft 11a, the teeth 21a and 22aB of the external gear 21 and the internal gear 22B are mutually connected. Interference can be suppressed, thereby making it possible to effectively prevent rotation transmission unevenness.

  According to the drive transmission mechanism 20C according to the third embodiment, the external gear 21A is negatively displaced so that the tooth 21aA gradually decreases from the proximal end E1 to the distal end E2 in the rotation axis direction (in this example, the width direction Y). The internal gear 22B is positively displaced so that the tooth 22aB gradually decreases from the distal end side E4 to the proximal end side E3 in the rotational axis direction (in this example, the width direction Y). Even if the other rotation shaft is inclined with respect to one of the rotation shafts 11a and 32a on the driven side, the interference between the teeth 21aA and 22aB of the external gear 21A and the internal gear 22B is further suppressed. This makes it possible to more effectively prevent rotation transmission unevenness.

  Furthermore, according to the image forming apparatus 100, any one of the drive transmission mechanisms 20A to 20C according to the first to third embodiments is provided, and thereby, rotation transmission unevenness can be effectively prevented. The periodic unevenness corresponding to the rotational transmission unevenness of the formed image can be suppressed.

  Further, in the drive transmission mechanism 20A according to the first embodiment, the internal gear 22 has a standardized tooth profile, so that a general-purpose gear can be used as the internal gear 22, and the drive transmission mechanism 20A can be made inexpensive. Can be a thing.

  In the drive transmission mechanisms 20A and 20C according to the first and third embodiments, the absolute value of the dislocation amount per unit distance in the rotation axis direction (in this example, the width direction Y) of the external gears 21A and 21A is constant. Alternatively, the tooth shapes of the external gears 21A and 21A can be easily formed by being substantially constant.

  In the drive transmission mechanisms 20A and 20C according to the first embodiment and the third embodiment, a constant or substantially constant shift amount per unit distance in the rotation axis direction (in this example, the width direction Y) of the external gears 21A and 21A. Of the external gears 21A, 21A and the internal gears 22, 22B, the teeth (21aA, 21aA), (22a, 22aB) of the external gears 21A, 21A and the internal gears 22, 22B increase in a stepwise manner from the proximal end E1 to the distal end E2. ) Part interference can be further suppressed, which makes it possible to more effectively prevent rotation transmission unevenness.

  Further, in the drive transmission mechanisms 20A and 20C according to the first embodiment and the third embodiment, the absolute value of the dislocation amount per unit distance in the rotation axis direction (in this example, the width direction Y) of the external gears 21A and 21A is based. By gradually increasing from the end side E1 to the front end side E2, interference between the (tooth 21aA, 21aA) and (22a, 22aB) portions of the external gears 21A, 21A and the internal gears 22, 22B is further suppressed. As a result, rotation transmission unevenness can be more effectively prevented.

  Further, in the drive transmission mechanism 20B according to the second embodiment, the external gear 21 has a standard tooth profile, so that a general-purpose gear can be used as the external gear 21, and the drive transmission mechanism 20B can be made inexpensive. Can be a thing.

  In the drive transmission mechanisms 20B and 20C according to the second and third embodiments, the absolute value of the dislocation amount per unit distance in the rotation axis direction (in this example, the width direction Y) of the internal gears 22B and 22B is constant. Alternatively, the tooth shapes of the internal gears 22B and 22B can be easily formed by being substantially constant.

  In the drive transmission mechanisms 20B and 20C according to the second and third embodiments, a constant or substantially constant shift amount per unit distance in the rotation axis direction (in this example, the width direction Y) of the internal gears 22B and 22B. Of the external gears 21, 21A and the internal gears 22B, 22B, the teeth (21a, 21aA), (22aB, 22aB) of the external gears 21, 21A and the internal gears 22B, 22B. ) Part interference can be further suppressed, which makes it possible to more effectively prevent rotation transmission unevenness.

  In the drive transmission mechanisms 20B and 20C according to the second and third embodiments, the absolute value of the dislocation amount per unit distance in the rotation axis direction (in this example, the width direction Y) of the internal gears 22B and 22B is the tip. By gradually increasing from the side E4 to the base end side E3, interference between the teeth (21a, 21aA) and (22aB, 22aB) of the external gears 21, 21A and the internal gears 22B, 22B is further suppressed. As a result, rotation transmission unevenness can be more effectively prevented.

(Other embodiments)
In this embodiment, the present invention is applied to the drive transmission mechanism that transmits the rotational driving force from the driving side to the photosensitive member 11 in the driven photosensitive unit 10, but the rotational driving force is transmitted from the driving side to the driven side. For example, in an image forming apparatus, a rotational driving force is applied from a driving side to a developer carrying member (specifically, a developing roller) in a driven-side developing device in an image forming apparatus. It can be applied to a drive transmission mechanism that transmits

  The present invention is not limited to the embodiment described above, and can be implemented in various other forms. Therefore, such an embodiment is merely an example in all respects and should not be interpreted in a limited manner. The scope of the present invention is shown by the scope of claims, and is not restricted by the text of the specification. Further, all modifications and changes belonging to the equivalent scope of the claims are within the scope of the present invention.

DESCRIPTION OF SYMBOLS 10 Photoconductor unit 10a Photoconductor unit main body 11 Photoconductor 11a Rotating shaft 12 Charging device 13 Exposure device 14 Development device 15 Transfer device 16 Cleaning device 20 Drive transmission mechanism 20A Drive transmission mechanism 20B Drive transmission mechanism 20C Drive transmission mechanism 21 External gear 21A External gear 21a Teeth 21a1 Mountain 21a2 Valley 21aA Teeth 22 Internal gear 22B Internal gear 22a Teeth 22a1 Mountain 22a2 Valley 22aB Teeth 30 Drive device 30a Front plate 30b Rear plate 30c Left plate 30d Right plate 31 Drive motor 31a Rotating shaft 32 Rotating shaft 32a Bearing 33 Drive transmission portion 33a Motor gear 33b Drive gear 33c Intermediate gear 34 Support shaft 34a Bearing 100 Image forming apparatus 101 Front plate 101a Positioning pin 102 Rear side plate 102a Positioning pin 110 Image forming apparatus main body 110a Front frame 110a1 Removable hole 110b Opening / closing lid 110b1 Positioning hole 110b2 Front side regulating member 110c Rear frame 110c1 Positioning hole 110c2 Rear side regulating member 111 Image forming part E1 Base end side E2 Front end side E3 Base end side E4 Front end side P Recording sheet Q1 Change point Q2 Change Point X Left-right direction Y Width direction Y1 One side Y2 The other side Z Vertical direction α Interference part β1 Dislocation region β2 Dislocation region γ1 Dislocation region γ2 Dislocation region

Claims (10)

A drive transmission mechanism for transmitting rotational drive force from the drive side to the driven side,
An external gear and an internal gear,
The rotational driving force is transmitted from the driving side to the driven side by meshing between the external gear and the internal gear.
The external gear is negatively displaced so that the teeth gradually become smaller from the proximal end side to the distal end side in the rotation axis direction ,
The absolute value of the dislocation amount per unit distance in the rotation axis direction of the external gear is constant or substantially constant,
The drive transmission mechanism, wherein an absolute value of a constant or substantially constant dislocation amount per unit distance in the rotation axis direction of the external gear increases stepwise from the base end side to the tip end side. . A drive transmission mechanism for transmitting rotational drive force from the drive side to the driven side,
An external gear and an internal gear,
The rotational driving force is transmitted from the driving side to the driven side by meshing between the external gear and the internal gear.
The internal gear is positively displaced so that the teeth gradually become smaller from the distal end side to the proximal end side in the rotation axis direction ,
The absolute value of the amount of dislocation per unit distance in the rotational axis direction of the internal gear is constant or substantially constant,
A drive transmission mechanism characterized in that the absolute value of a constant or substantially constant dislocation amount per unit distance of the internal gear in the direction of the rotation axis increases stepwise from the distal end side toward the proximal end side. . A drive transmission mechanism for transmitting rotational drive force from the drive side to the driven side,
An external gear and an internal gear,
The rotational driving force is transmitted from the driving side to the driven side by meshing between the external gear and the internal gear.
The external gear is negatively displaced so that the teeth gradually become smaller from the proximal end side to the distal end side in the rotation axis direction,
The drive transmission mechanism according to claim 1, wherein the internal gear is positively displaced so that the teeth gradually become smaller from the distal end side to the proximal end side in the rotation axis direction. The drive transmission mechanism according to claim 3 ,
An absolute value of a dislocation amount per unit distance in the rotation axis direction of the external gear is constant or substantially constant. The drive transmission mechanism according to claim 4,
The drive transmission mechanism, wherein an absolute value of a constant or substantially constant dislocation amount per unit distance in the rotation axis direction of the external gear increases stepwise from the base end side to the tip end side. . A drive transmission mechanism according to any one of claims 3 to 5 ,
An absolute value of a displacement amount per unit distance in the rotation axis direction of the internal gear is constant or substantially constant. The drive transmission mechanism according to claim 6,
A drive transmission mechanism characterized in that the absolute value of a constant or substantially constant dislocation amount per unit distance of the internal gear in the direction of the rotation axis increases stepwise from the distal end side toward the proximal end side. .   An image forming apparatus comprising the drive transmission mechanism according to any one of claims 1 to 7. A drive transmission mechanism for transmitting rotational drive force from the drive side to the driven side,
An external gear and an internal gear,
The rotational driving force is transmitted from the driving side to the driven side by meshing between the external gear and the internal gear.
The image forming apparatus according to claim 1, wherein the external gear includes a drive transmission mechanism that is negatively displaced so that the teeth gradually become smaller from the proximal end side to the distal end side in the rotation axis direction. A drive transmission mechanism for transmitting rotational drive force from the drive side to the driven side,
An external gear and an internal gear,
The rotational driving force is transmitted from the driving side to the driven side by meshing between the external gear and the internal gear.
The image forming apparatus according to claim 1, wherein the internal gear includes a drive transmission mechanism that is positively shifted so that teeth gradually become smaller from the distal end side to the proximal end side in the rotation axis direction.

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