JP5202162B2 - Image forming apparatus - Google Patents

Description

  The present invention relates to an image forming apparatus that forms an image on a recording sheet.

  In recent years, image forming apparatuses employing an electrophotographic system such as a laser beam printer or a copying machine are required to be smaller and less expensive.

  In addition, in order to improve the maintainability of the device and to reduce running costs, the image forming device is configured so that components such as process cartridges and intermediate transfer members in the image forming device are unitized, and the unit can be removed from the device body by users and service personnel. The device is common.

  As such a conventional example, in order to make the developing cartridge detachable from the image forming apparatus main body, the apparatus main body side coupling portion, which is a drive transmission means, is connected in the rotation axis direction in conjunction with the opening / closing operation of the top cover of the apparatus main body. Have been proposed (see Patent Document 1).

JP 2006-154746 A

  However, in the conventional image forming apparatus described above, a link mechanism having a certain degree of strength is required to link the opening / closing door and the coupling retracting operation, which hinders downsizing and cost reduction of the apparatus. .

  Accordingly, the present invention provides an image forming apparatus excellent in operability in which a unit having a coupling mechanism as drive transmission means can be easily detached from an image forming apparatus main body without hindering downsizing and cost reduction of the apparatus. The purpose is to provide.

In order to solve the above problems, a typical configuration of an image forming apparatus according to the present invention includes an apparatus main body, a rotatable drive coupling that transmits a driving force , and a rotation that is transmitted by the driving force transmitted from the driving coupling. to a unit comprising a driven coupling, it has a, the unit is moved the in is removed from the apparatus main body, wherein the substantially vertical first direction and the rotation axis of the driven coupling to said apparatus body in a possible image forming apparatus, at least one of said drive coupling and said driven coupling is provided with an inclined portion, the operating force for detaching the detachable unit and the inclined portion, the drive only inclined with respect to the rotation axis of at least one of the coupling or the driven coupling, having a drive transmission releasing mechanism for releasing the drive transmission And features.
In order to solve the above problems, another typical configuration of the image forming apparatus according to the present invention includes an apparatus main body, a rotatable drive coupling that transmits a driving force, and a unit that can be attached to and detached from the apparatus main body. A unit having a rotatable driven coupling that receives the driving force from the driving coupling, and the unit is driven with respect to the device main body when the unit is removed from the device main body. In the image forming apparatus that is movable in a first direction substantially perpendicular to the rotation axis of the coupling, one of the drive coupling or the driven coupling includes an inclined portion, and the rotation axis of the driven coupling The device is movable in a substantially parallel second direction, and the other of the drive coupling or the driven coupling has a contact portion that can contact the inclined portion, and the device When the unit is removed from the body, the unit moves in the first direction with the inclined portion and the contact portion in contact with each other, so that either the driving coupling or the driven coupling is One of the couplings movable in the second direction moves in the second direction and is inclined with respect to the rotation axis.
In order to solve the above problems, another typical configuration of the image forming apparatus according to the present invention includes an apparatus main body, a rotatable drive coupling that transmits a driving force, and a unit that can be attached to and detached from the apparatus main body. And a unit having a rotatable driven coupling that engages with the drive coupling and receives the driving force from the drive coupling, and when the unit is detached from the apparatus main body, In the image forming apparatus that is movable in a first direction substantially perpendicular to the rotation axis of the driven coupling with respect to the apparatus main body, one of the driving coupling or the driven coupling includes an inclined portion, and The device body can be inclined with respect to a rotation axis, and the other of the drive coupling or the driven coupling includes a contact portion that can contact the inclined portion, When the unit is removed, either the drive coupling or the driven coupling from the state where the inclined portion and the contact portion are in contact with each other by moving the unit in the first direction. One of the couplings capable of tilting with respect to the rotating shaft is tilted with respect to the rotating shaft, whereby the engagement between the drive coupling and the driven coupling is released.

  According to the present invention, a unit having a coupling mechanism as a drive transmission means can be easily attached to and detached from the image forming apparatus main body without hindering downsizing and cost reduction of the apparatus.

  An embodiment of an image forming apparatus according to the present invention will be described with reference to the drawings. FIG. 1 is a configuration diagram of an image forming apparatus according to the present embodiment.

(Image forming device)
As shown in FIG. 1, the four-drum full-color image forming apparatus 1 of this embodiment includes process cartridges PY, PM, PC, PK, and an intermediate transfer belt unit 6.

  The process cartridges PY to PK include photosensitive drums 2Y, 2M, 2C, and 2K that are image carriers, charging rollers 3Y, 3M, 3C, and 3K, and developing units 4Y, 4M, 4C, and 4K. The process cartridges PY to PK include yellow (Y), magenta (M), cyan (C), and black (K) developers (toners), respectively. The process cartridge P is detachably attached to the apparatus main body 1.

  The photosensitive drum 2 is rotatably supported at both ends, is driven and transmitted from one end by a drive motor and drive transmission means (not shown), and is rotated in the clockwise direction in FIG.

  Each of the photosensitive drums 2Y to 2K has a surface coated with an organic photoconductor layer, and the surface is uniformly charged by applying a charging bias to the charging rollers 3Y to 3K. A laser beam emitted from a laser scanner device (exposure means) 5 is selectively exposed to form an electrostatic latent image. The electrostatic latent image is developed as a toner image by attaching toner of each color by the developing means 4Y to 4K.

  The unit 6 includes an intermediate transfer belt 7, a driven roller 8, primary transfer rollers 9Y, 9M, 9C, and 9K, and a driving roller 10. The intermediate transfer belt 7 is stretched by a driving roller 10 and a driven roller 8. The intermediate transfer belt 7 is sandwiched between the primary transfer rollers 9Y to 9K and the photosensitive drums 2Y to 2K, and the drive roller 10 is rotated by a drive motor and drive transmission means (not shown), whereby the counterclockwise of FIG. It is rotationally driven in the turning direction.

  A predetermined transfer bias is applied to the primary transfer rollers 9Y to 9K, and the respective color toner images on the surfaces of the photosensitive drums 2Y to 2K are sequentially superimposed on the intermediate transfer belt 7 and transferred to form four-color toner images. .

  A recording sheet S is stacked on the feeding cassette 11. The recording sheet S is fed by a feeding roller 12 that is driven at a predetermined timing by a drive motor and drive transmission means (not shown). The fed recording sheet S is conveyed by the conveyance roller pair 13 and the registration roller pair 14 and is conveyed to the secondary transfer position where the intermediate transfer belt 7 and the secondary transfer roller 15 are in contact with each other. The recording sheet S conveyed to the secondary transfer position is transferred with the four color toner images on the intermediate transfer belt 7 by the secondary transfer roller 15 to which a predetermined bias is applied.

  The recording sheet S to which the toner image has been transferred is conveyed to the fixing roller pair 16 and the toner image is fixed by heat and pressure. The recording sheet S on which the toner image is fixed is discharged and stacked on the discharge tray by the discharge roller pair 17.

(Intermediate transfer belt unit 6)
FIG. 2 is a perspective view of the intermediate transfer belt unit 6 removed from the apparatus main body 1. FIG. 3 is a perspective view of the guide rail 22.

  When the opening / closing door (not shown) is opened, the secondary transfer roller 15 is released from the intermediate transfer belt 7 and retracted together with the opening / closing door. In this state, the unit 6 can be detached from the apparatus main body 1 in the direction of arrow A.

  As shown in FIG. 2, the unit 6 includes a unit holding boss 18 and a driven coupling 20. Two unit holding bosses 18 are provided on each of the left and right frames of the unit 6 in a total of four locations.

  As shown in FIG. 3, the guide rail 22 has a rail portion 19 and a drive coupling 21. The guide rail 22 is configured such that when the unit 6 is attached to or detached from the apparatus main body 1, the rail portion 19 that guides the posture of the unit 6 guides the four unit holding bosses 18 in the direction of arrow A, thereby Guides attachment / detachment to / from.

  The drive coupling 21 transmits a rotational driving force to the driven coupling 20 by rotating around the rotation axis. The primary transfer roller 9 (intermediate transfer belt 7) and the photosensitive drum 2 are brought into contact with and separated from each other by rotationally driving the drive coupling 21 and the driven coupling 20 by a drive source (not shown) in the apparatus main body.

  Here, the contact / separation operation of the primary transfer roller 9 (intermediate transfer belt 7) and the photosensitive drum 2 will be described in detail.

  FIG. 4 is a configuration diagram of a mechanism related to the contact and separation of the primary transfer roller in the unit 6. As shown in FIG. 4, when the driven coupling 20 driven by the driving coupling 21 provided in the apparatus main body 1 rotates, the contact / separation cams 29 and 30 rotate via the cam shaft (rotating shaft) 23. To do. The cam sliders 25 and 26 and the cam sliders 27 and 28 slide according to the rotation angle of the contact / separation cams 29 and 30, respectively. The cam sliders 25 and 26 swing the primary transfer roller bearings 24Y to 24C. The cam sliders 27 and 28 swing the primary transfer roller bearing 24K.

  As the primary transfer roller bearings 24Y to 24C swing, the primary transfer rollers 9Y to 9C move up and down and abut against and separate from the photosensitive drum 2. As the primary transfer roller bearing 24K swings, the primary transfer roller 9K moves up and down and contacts and separates from the photosensitive drum 2.

  In this embodiment, by rotating the driven coupling 20 every 120 °, the full separation mode (all primary transfer rollers 9 are separated), the full color mode (all primary transfer rollers 9 are in contact). The three modes of the mono mode (only the primary transfer roller 9K is in contact) are switched.

  FIG. 5 is a schematic view showing a state in which the driven coupling 20 and the driving coupling 21 are engaged. As shown in FIG. 5, at the time of driving transmission, the drive coupling 21 rotates counterclockwise in FIG. 5, thereby rotating the driven coupling 20 and controlling the contact / separation state of the primary transfer roller 9. ing.

(Conventional coupling)
Here, in the conventional coupling, consider a case where the unit 6 is detached from the apparatus main body 1 when the couplings are engaged with each other in the state shown in FIG. When the unit 6 is removed to the left in the horizontal direction in FIG. 5 (the driven coupling 20 moves to the left in FIG. 5), the couplings can move. On the other hand, when the unit 6 is removed in the other direction, for example, the vertical direction in FIG. 5, the couplings collide with each other and the unit 6 cannot be removed. Such a phenomenon is not limited to the two-point driving coupling shape taken up in the present embodiment, and becomes more prominent as the number of driving points increases.

  Therefore, when it is necessary to attach or detach a unit having a coupling in a direction perpendicular to the rotation axis of the coupling, a coupling retracting mechanism as used in the conventional example is provided. In this conventional coupling retracting mechanism, one coupling is retracted before attaching / detaching the unit, and the unit is attached / detached in a state where the couplings do not interfere with each other.

  However, the above-described conventional coupling requires a coupling retracting operation in addition to the attaching / detaching operation of the unit 6, and the operability is poor. Further, even when the coupling retracting operation is interlocked with the opening / closing of the open / close door, a link mechanism is required, and there is a problem that miniaturization and cost reduction of the apparatus are hindered.

(Coupling of this embodiment, drive transmission release mechanism)
FIG. 6 is a cross-sectional view of the coupling configuration and drive transmission release mechanism of the present embodiment. 7 and 8 are schematic views showing a state in which the drive coupling 21 is retracted while being inclined with respect to the cam shaft (rotary shaft) 23. FIG.

  As shown in FIG. 6, the drive coupling 21 is provided so as to be movable with respect to the drive gear 36. The drive coupling 21 has a spherical portion 21a. A parallel pin (engagement convex portion) 40 is press-fitted into the spherical portion 21a.

  The drive gear 36 is rotatably held with respect to the apparatus main body 1. The drive gear 36 has a drive coupling spring (biasing means) 33 and an engagement recess 36a. The drive coupling spring 33, the parallel pin 40, and the engagement recess 36a constitute a drive transmission release mechanism.

  The spring 33 is provided between the drive gear 36 and the drive coupling 21. The spring 33 biases the drive coupling 21 toward the driven coupling 20 in the rotation axis direction (arrow X direction).

  The engaging recess 36a is perforated in the rotation axis direction. The parallel pin 40 is engaged with the engagement recess 36a in the rotation direction (direction around the rotation axis) and is movably engaged in the rotation axis direction. That is, it can be slid in the direction of the rotation axis or moved in an inclined state.

  When the drive gear 36 is rotationally driven by a drive source (not shown) in the apparatus main body 1, the driving transmission is transmitted from the engagement recess 36 a to the parallel pin 40, and the drive coupling 21 is rotationally driven integrally with the drive gear 36. Is done.

  The driving coupling 21 has a coupling portion 21 b that is provided at the other end of the spherical portion 21 a and engages with the driven coupling 20. As shown in FIGS. 7 and 8, when the drive transmission is canceled, a force is applied to the coupling portion 21b in a direction intersecting the rotation axis direction, and the drive coupling 21 has the spherical portion 21a as the center of rotation. Rotate in a direction intersecting the rotation axis. At this time, the parallel pin 40 is inclined in the engagement recess 36a. However, as shown in FIG. 3, the drive coupling 21 is restricted by the elongated hole 22 a of the guide rail 22 so as to be inclined only in the direction in which the intermediate transfer belt unit 6 is taken out.

  The driven coupling 20 is attached so as not to tilt with respect to the cam shaft 23.

(Removal of unit 6 to / from apparatus body 1)
Here, a case where the unit 6 is attached to and detached from the apparatus main body 1 will be described.

  First, the case where the unit 6 is attached to the apparatus main body 1 will be described. When the unit 6 is attached to the apparatus main body 1, the driven coupling 20 approaches the driving coupling 21 from a direction perpendicular to the rotation axis as shown in FIG. 9. Then, the tapered surface 20 a provided on the outer peripheral surface of the driven coupling 20 and the tapered surface 21 c provided on the outer peripheral surface of the driving coupling 21 abut.

  Further, when the unit 6 is pushed in, the driven coupling 20 moves in the vertical direction and presses the driving coupling 21. At this time, the drive coupling 21 is in contact with the elongated hole 22a of the guide rail 22 and cannot move in the vertical direction. For this reason, the drive coupling 21 is retracted in the direction of the rotation axis without being inclined with respect to the rotation axis. As a result, the unit 6 is set in a state in which the tapered surface 20a gets over the tapered surface 21c and the rotation shafts are aligned with each other so that drive transmission is possible.

  Then, by the initial operation before the image forming operation, the mutual coupling is brought into the engaged state shown in FIG. 5, and the contact and separation control of the primary transfer roller 9 is possible.

  Next, a case where the unit 6 is removed from the apparatus main body 1 will be described.

  In the image forming apparatus of the present embodiment, the removal direction of the unit 6 is the left side in the horizontal direction in FIG. 5 so that the engaged coupling can be easily removed at the home position (totally separated state) of the primary transfer roller 9. It is controlled to become.

  In this way, when the couplings do not interfere with each other, the unit 6 is pulled out of the apparatus main body 1 in the direction of arrow A (the direction of detachment). At this time, the driven coupling 20 moves to the left side in FIG. 5 and the unit 6 can be easily removed without interference between the couplings.

  However, when the recording sheet is jammed during image formation or when the user opens the door provided in the apparatus body, the apparatus body 1 is in an emergency stop state, and the coupling is performed in the above-described phase. It may not stop. In such a case, as described with reference to FIG. 5, it is necessary to remove the unit 6 in a direction in which the engaged couplings interfere with each other.

  A case where the couplings interfere with each other (in FIG. 6, the case where the driven coupling 20 moves downward in the vertical direction) will be described. In this case, the tapered surface 20 a of the driven coupling 20 presses the tapered surface 21 d provided on the inner peripheral surface of the driving coupling 21. Due to the operating force when pulling out the unit 6, the drive coupling 21 is tilted in the disengagement direction (downward in the direction of arrow Y in FIG. 6) and resists the biasing force of the spring 33 in the direction of the rotation axis (in the direction of arrow X). Slide away.

  As described above, according to the present embodiment, the drive coupling 21 is positively inclined when the unit 6 is removed from the apparatus main body 1 without using a coupling retracting mechanism linked to a door or the like. At the same time, the driven coupling 20 causes the retraction operation to be smoothly performed in the direction of the rotation axis of the drive gear 36 due to the inclination, so that the coupling release operation is performed with a small operating force.

  In this embodiment, the drive coupling 21 side is inclined. However, at least one of the drive coupling or the driven coupling is inclined with respect to the rotation axis, and the drive transmission to the other may be canceled. The coupling 20 side may be inclined. The coupling retracted in the direction of the rotation axis may be a driven side coupling. Further, the drive coupling 21 may be tilted when the unit is attached.

  In addition, the application example of the drive coupling that bears and separates the transfer roller has been described. However, the present invention relates to a drive coupling provided in a unit that is detachable from the apparatus main body, including a photosensitive drum and an intermediate transfer belt. It can also be applied to the department.

1 is a configuration diagram of an image forming apparatus according to an exemplary embodiment. FIG. 3 is a perspective view of an intermediate transfer belt unit removed from the apparatus main body. It is a perspective view of a guide rail. FIG. 4 is a diagram illustrating a primary transfer roller contact / separation mechanism in an intermediate transfer belt unit. It is the schematic diagram which showed the state which the to-be-driven coupling and the drive coupling engaged. It is sectional drawing of a coupling structure and a drive transmission cancellation | release mechanism. It is a schematic diagram of the state in which the drive coupling retracted by tilting with respect to the rotation axis. It is a schematic diagram of the state in which the drive coupling retracted by tilting with respect to the rotation axis. FIG. 6 is an explanatory diagram illustrating how the intermediate transfer belt unit is attached to the apparatus main body.

Explanation of symbols

P ... Process cartridge S ... Recording sheet 1 ... Image forming apparatus 2 ... Photosensitive drum 3 ... Charging roller 4 ... Developing means 5 ... Laser scanner device 6 ... Intermediate transfer belt unit 7 ... Intermediate transfer belt 8 ... Follower roller 9 ... Primary roller Transfer roller 10 ... Driving roller 11 ... Feed cassette 12 ... Feed roller 13 ... Conveying roller pair 14 ... Registration roller pair 15 ... Secondary transfer roller 16 ... Fixing roller pair 17 ... Discharge roller pair 18 ... Unit holding boss 19 ... Rail Part 20 ... Driven couplings 20a, 21c, 21d ... Tapered surface 21 ... Drive coupling 21a ... Spherical part 22 ... Guide rail 22a ... Slot 23 ... Cam shaft 24 ... Primary transfer roller bearings 25 to 28 ... Cam slider 29 , 30 ... abutment / separation cam 33 ... drive coupling spring 36 ... drive gear 36a ... engagement recess 40 ... Parallel pin

Claims (7)

The device body;
A rotatable drive coupling that transmits drive force ; and
Have a, a unit comprising a driven coupling which rotates is transmitted a driving force from said drive coupling, the unit, when detached from the apparatus main body, the driven coupling to said apparatus body In an image forming apparatus that is movable in a first direction substantially perpendicular to the rotation axis of
At least one of the driving coupling or the driven coupling includes an inclined portion ,
By the operation force for detaching the detachable unit and the inclined portion, only inclined with respect to the rotation axis of at least one of the drive coupling or the driven coupling, the drive transmission releasing mechanism for releasing the drive transmission An image forming apparatus comprising: The drive transmission release mechanism is provided in a drive gear that transmits drive to the drive coupling, and an engagement recess that is perforated in a rotation axis direction;
An engagement projection provided in the drive coupling, engaged in the rotation direction with the engagement recess, and movable in the rotation axis direction;
Biasing means for biasing the drive coupling to the driven coupling;
At the time of driving transmission, the urging means urges the driving coupling to the driven coupling, and the driving coupling and the driven coupling are engaged,
2. The drive transmission is canceled when the drive transmission is released, the engagement convex portion and the drive coupling are inclined with respect to the rotation shaft against the urging force of the urging means. Image forming apparatus. An apparatus main body, a rotatable drive coupling for transmitting a driving force, and a unit that is detachable from the apparatus main body and includes a rotatable driven coupling that receives the driving force from the driving coupling. In the image forming apparatus, the unit is movable in a first direction substantially perpendicular to a rotation axis of the driven coupling with respect to the apparatus body when the unit is detached from the apparatus body.
One of the driving coupling or the driven coupling includes an inclined portion and is movable in a second direction substantially parallel to the rotation axis of the driven coupling,
The other of the driving coupling or the driven coupling has a contact portion that can contact the inclined portion,
When the unit is removed from the apparatus main body, the drive coupling or the driven coupling is caused by the unit moving in the first direction in a state where the inclined portion and the contact portion are in contact with each other. An image forming apparatus, wherein one of the couplings movable in the second direction moves in the second direction and is tilted with respect to the rotation axis. The image forming apparatus according to claim 3, wherein the contact portion is another inclined portion that can contact the inclined portion and is substantially parallel to the inclined portion. The unit is a belt unit including a belt for conveying a toner image transferred from an image carrier. The belt unit includes a transfer member that can contact and separate from the belt, and the driven coupling is The image forming apparatus according to claim 1, wherein the transfer member moves relative to the belt by rotating . An apparatus main body, a rotatable drive coupling that transmits a driving force, and a unit that can be attached to and detached from the apparatus main body, engage with the drive coupling, and receive the driving force from the drive coupling. A unit including a driven coupling, and the unit is movable in a first direction substantially perpendicular to a rotation axis of the driven coupling with respect to the apparatus main body when the unit is detached from the apparatus main body. In the image forming apparatus,
One of the driving coupling or the driven coupling includes an inclined portion and can be inclined with respect to the rotation axis.
The other of the drive coupling or the driven coupling includes a contact portion that can contact the inclined portion,
When the unit is removed from the apparatus main body, the drive coupling or the driven coupling is brought into contact with the inclined portion and the contact portion by moving the unit in the first direction. The coupling that can be tilted with respect to any one of the rotating shafts is disengaged from the driving coupling and the driven coupling by tilting with respect to the rotating shaft. Image forming apparatus. The image forming apparatus according to claim 6, wherein the contact portion is another inclined portion that can contact the inclined portion and is substantially parallel to the inclined portion.

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