JP5163025B2 - Image forming apparatus - Google Patents

Description

  The present invention relates to an image forming apparatus such as a printer or a copying machine.

  In order to enable driving of an image carrier such as a photosensitive drum to be switched between a full color mode and a monochrome mode, a first rotating body that rotates the monochrome photosensitive drum when the drive selection member is at the first position, and a drive There has been proposed an image forming apparatus including a second rotating body that rotationally drives the color photosensitive drum when the selection member is at the first position and rotationally drives the monochrome photosensitive drum when the selection member is at the second position. (For example, refer to Patent Document 1).

Japanese Patent Laid-Open No. 7-181773

By the way, in an image forming apparatus, there may be a plurality of modes in which image formation is performed without using a part of a plurality of provided image carriers.
An object of the present invention is to provide an image forming apparatus capable of easily realizing rotation and stop of an image carrier in each mode in which some image carriers are not used.

The invention according to claim 1, rotatably disposed, a plurality of image holding body that holds a toner image, provided corresponding to each of the image carrier of the plurality of image carriers Rutotomoni, the A plurality of holding body side couplings provided so as to be rotatable around a rotation axis along the axial direction of the image holding body and provided coaxially with the image holding body and capable of transmitting a driving force to the image holding body. and member, wherein the plurality of holder side coupling member each provided corresponding to the Rutotomoni rotatably provided around a rotation axis along the axial direction of the holding side coupling member, and, the holder side provided the coupling member and coaxially, a plurality of drive-side coupling member and the holding side coupling member said image carrier through by being connected to the holding side coupling member is rotated, the plurality of Drive The holder side coupling member of the first group of drive-side coupling member moved back and forth along the axial direction of the driving-side coupling member, corresponding to the drive-side coupling member of the first group of the coupling member And a first coupling mechanism for coupling / releasing the coupling and a second group of driving coupling members among the plurality of driving coupling members to advance and retract along the axial direction of the driving coupling member. A second connection mechanism for connecting / disconnecting the second group drive side coupling member and the corresponding holding body side coupling member, and the first connection mechanism releases the connection and the second connection mechanism releases the connection. An image having a first mode in which the connection is made by two connection mechanisms and a second mode in which the connection is made by the first connection mechanism and the connection is released by the second connection mechanism. It is formed apparatus.
According to a second aspect of the present invention, the drive side coupling member of at least one of the first group of drive side coupling members and the second group of drive side coupling members includes a plurality of drive side couplings. A slide member provided to be slidable in a predetermined direction, and provided to be interlocked with the plurality of drive side coupling members; and the shaft of the plurality of drive side coupling members The image forming apparatus according to claim 1, wherein the advancing and retreating along the direction is performed collectively by sliding the slide member.
The invention according to claim 3 is a driving side coupling member included in the driving side coupling member of the other group among the driving side coupling member of the first group and the driving side coupling member of the second group. The advancing and retreating along the axial direction is performed by sliding a second slide member provided so as to be interlocked with the drive side coupling member in a predetermined direction. Item 3. The image forming apparatus according to Item 2.
According to a fourth aspect of the present invention, the second slide member provided so as to be interlocked with the drive side coupling member included in the drive side coupling member of the other group is the drive of the one group. Provided to slide along the sliding direction of the slide member provided to interlock with the plurality of drive-side coupling members included in the side coupling member, and provided in a state of being overlapped with the slide member 4. The image forming apparatus according to claim 3, wherein the image forming apparatus is provided.
5. The image forming apparatus according to claim 1, further comprising a third mode in which the connection is made by the first connection mechanism and the connection is made by the second connection mechanism. It is.

The invention according to claim 6 further includes an apparatus main body part and a cover member that is attached to the apparatus main body part so as to be openable and closable and covers a part of the apparatus main body part, and the cover member is opened. As a result, the connection release by the first connection mechanism and the connection release by the second connection mechanism are performed, the drive side coupling member moves away from the holding body side coupling member, and the cover member is closed. When the operation is performed, the drive side coupling member does not advance toward the holding body side coupling member, and after the closing operation of the cover member is completed and the cover member is closed, the first After the coupling by the coupling mechanism and the coupling by the second coupling mechanism are performed and the cover member is closed, the drive side coupling member is coupled to the holding body side coupling. The image forming apparatus according to claim 1, wherein the advances toward the grayed member.
The invention according to claim 7 further includes a belt arranged in contact with each of the plurality of image holding members, and the belt is driven by the driving-side coupling member of the first group in the first mode. Arranged separately from the image carrier that is rotationally driven, and spaced apart from the image carrier that is rotationally driven by the second group drive side coupling member in the second mode. The image forming apparatus according to claim 1.
According to an eighth aspect of the present invention, the drive-side coupling member of the first group rotates and drives the image holding body that respectively holds yellow, magenta, and cyan toner images, and the drive side of the second group The image forming apparatus according to claim 1, wherein the coupling member rotationally drives the image holding body that holds a black toner image.
The invention according to claim 9 is provided corresponding to each of the plurality of image holding members disposed rotatably and the individual image holding members of the plurality of image holding members, and the axial direction of the image holding members. A plurality of holding body side coupling members that are provided so as to be rotatable around a rotation axis along the axis and coaxial with the image holding body and capable of transmitting a driving force to the image holding body, Provided corresponding to each of the holding body side coupling members, provided rotatably about a rotation axis along the axial direction of the holding body side coupling member, and coaxial with the holding body side coupling member A plurality of drive-side coupling members that are provided and connected to each of the plurality of holding-body-side coupling members, and that rotate the image holding body via the holding-body-side coupling member; and the driving-side coupling member A connection release mechanism that advances and retracts along the axial direction of the drive side coupling member and connects or releases the drive side coupling member and the holding body side coupling member, and the connection release mechanism includes the plurality of connection release mechanisms. Of the first group of the driving side coupling members of the first coupling group and the corresponding coupling member of the holding body side coupling member, and the second group of driving side coupling members not belonging to the first group. Selectively connecting or releasing the corresponding holding body side coupling member and connecting or releasing all the driving side coupling members of the plurality of driving side coupling members to the corresponding holding body side coupling member. An image forming apparatus characterized in that
According to a tenth aspect of the present invention, the connection release mechanism rotates in one direction to connect the drive side coupling member with the corresponding holding body side coupling member, and rotates in the other direction. The image forming apparatus according to claim 9, further comprising a drive member that releases the connection between the drive side coupling member and the corresponding holding body side coupling member.
According to an eleventh aspect of the present invention, the connection release mechanism includes a first slide member that connects or releases the driving side coupling member of the first group and the corresponding holding body side coupling member by sliding. A second slide member that connects or releases the second group drive side coupling member and the corresponding holding body side coupling member by sliding, and the first slide member and the second slide member. The image forming apparatus according to claim 9, wherein the image forming apparatus is disposed so as to overlap with the slide member.
According to a twelfth aspect of the present invention, the connection release mechanism moves forward and backward with respect to the holding body side coupling member in conjunction with the slide of the first slide member, and corresponds to the drive side coupling member of the first group. A first advancing / retreating member for connecting or releasing with the holding body side coupling member; and a driving side coupling of the second group that moves forward and backward with respect to the holding body side coupling member in conjunction with the sliding of the second slide member. A second advancing / retreating member that connects or releases the corresponding member to the holding body side coupling member, and the first advancing / retreating member and the second advancing / retreating member include the first slide member and the second advancing / retreating member. The image forming apparatus according to claim 11, wherein the image forming apparatus is disposed on one slide member side of the two slide members.
According to a thirteenth aspect of the present invention, the forward / backward movement of the first slide member and the second slide member, which is arranged to be interlocked with the slide of the other slide member, is arranged on the one slide member side. The image forming apparatus according to claim 12, wherein the member is interlocked with the other slide member through a through hole formed in the one slide member.

According to the first aspect of the present invention, there is provided an image forming apparatus capable of easily rotating and stopping the image carrier while maintaining driving accuracy by coupling in each mode in which some image carriers are not used. be able to.
According to the fifth aspect of the present invention, for example, full-color image formation is possible.
According to the sixth aspect of the present invention, compared with the case where the present invention is not adopted, even if the cover member is opened and closed, the user can easily replace the rotating member as compared with the case where the coupling member is connected. The image can be formed by the operation of the first and second connecting mechanisms after the closing.
According to the seventh aspect of the present invention, it is possible to prevent the image carrier from being rotated by the belt.
According to the eighth aspect of the present invention, it is possible to stop the rotation of the image carrier that is not used when an image is formed by process black.

According to the ninth aspect of the present invention, there is provided an image forming apparatus capable of easily realizing rotation and stop of the image carrier while maintaining driving accuracy by coupling in each mode in which some image carriers are not used. be able to.
According to Claim 10 of this invention, compared with the case where this invention is not employ | adopted, connection with a holding body side coupling member and a drive side coupling member can be performed simply.
According to the eleventh aspect of the present invention, it is possible to reduce the size of the image forming apparatus with a simple configuration as compared with the case where the present invention is not adopted.
According to the twelfth aspect of the present invention, it is possible to reliably connect or release the drive side coupling member and the holding body side coupling member as compared with the case where the present invention is not adopted.
According to the thirteenth aspect of the present invention, as compared with the case where the present invention is not adopted, the advancing / retreating member disposed on one slide member side can be interlocked with the other slide member with a simple configuration.

Embodiments of the present invention will be described below in detail with reference to the accompanying drawings.
FIG. 1 is a diagram showing an overall configuration of an image forming apparatus to which the present invention is applied. An image forming apparatus 1 shown in FIG. 1 is a so-called tandem type digital color printer using an electrophotographic method, and an image for forming an image corresponding to image data of each color in a cover 2 and an apparatus main body 3. A formation process unit 24 is provided. Each unit provided in the image forming apparatus 1 and a control unit 22 that controls the operation of each device are provided. Furthermore, for example, an image processing unit 21 that performs predetermined image processing on image data received from a personal computer (PC) 5 or an image reading device 6 such as a scanner, a hard disk (Hard Disk) that stores processing programs, image data, and the like. Main memory unit 23 realized by Drive).

  In the image forming process section 24, four image forming units 10Y, 10M, 10C, and 10K (hereinafter also collectively referred to as “image forming unit 10”) are arranged in parallel in the vertical direction at a constant interval. Each image forming unit 10 develops a photosensitive drum 11 as an example of an image carrier, a charging roll 12 that charges the surface of the photosensitive drum 11, and an electrostatic latent image formed on the photosensitive drum 11 with each color toner. And a drum cleaner 14 for cleaning the surface of the photosensitive drum 11 after transfer. Further, each image forming unit 10 is arranged to be replaceable (detachable) with respect to the apparatus main body 3. For example, when the toner in the developing device 13 is consumed or when the photosensitive drum 11 reaches the end of its life. For example, the image forming unit is replaced in units of 10 units. In order to facilitate this replacement, the image forming unit 10 includes a gripping portion 17 that is gripped by a user or the like.

The charging roll 12 is composed of a roll member in which a conductive elastic body layer and a conductive surface layer are laminated on a conductive metal core such as aluminum or stainless steel. Then, a charging bias voltage is supplied from a charging power source (not shown), and the surface of the photosensitive drum 11 is uniformly charged at a predetermined potential while being driven to rotate relative to the photosensitive drum 11.
The developing device 13 holds a two-component developer composed of yellow (Y), magenta (M), cyan (C), and black (K) toners and a magnetic carrier in each of the image forming units 10, and is photosensitive. The electrostatic latent image formed on the body drum 11 is developed with each color toner.
The drum cleaner 14 brings a plate-like member formed of a rubber material such as urethane rubber into contact with the surface of the photosensitive drum 11 to remove toner, paper dust, and the like attached on the photosensitive drum 11.

  Further, the image forming apparatus 1 of the present embodiment is provided with a laser exposure device 20 that exposes the photosensitive drums 11 provided in each image forming unit 10. The laser exposure unit 20 acquires image data for each color from the image processing unit 21, and scans and exposes the photosensitive drum 11 of each image forming unit 10 with laser light whose lighting is controlled based on the acquired image data. To do. Further, the image forming apparatus 1 according to the present embodiment is provided with a sheet conveying belt 30 that moves in contact with the photosensitive drum 11 of each image forming unit 10 and conveys the sheet P that is a recording material (recording sheet). Has been. The paper transport belt 30 is formed of a film-like endless belt that electrostatically attracts the paper P. Further, the paper transport belt 30 is stretched around the idle roll 32 and the drive roll 33 and circulates, so that the paper P is transported between the photosensitive drum 11 from the lower side to the upper side in the substantially vertical direction. A path M1 is formed.

In addition, transfer rolls 31y, 31m, 31c, and 31k (hereinafter also referred to as “transfer roll 31”) are disposed at positions inside the paper conveyance belt 30 and facing the respective photosensitive drums 11 respectively. Each transfer roll 31 forms a transfer electric field with each photoconductor drum 11, and thereby each color toner image formed by each image forming unit 10 on the paper P held and transported by the paper transport belt 30. Are sequentially transferred. A neutralizing lamp (not shown) for neutralizing the photosensitive drum 11 after the transfer is provided outside the sheet conveying belt 30 and downstream of each transfer roll 31.
An adsorption roll 34 that charges the paper transport belt 30 is disposed at the most upstream portion of the paper transport belt 30 on the photosensitive drum 11 side. The surface of the paper transport belt 30 is electrostatically attracted to the paper P by being charged with a predetermined potential by the suction roll 34.
Further, a fixing device 28 is provided on the downstream side of the paper transport belt 30 and on the paper transport path M1 to perform a fixing process by heat and pressure on the unfixed toner image on the paper P.

Further, as a paper transport system other than the paper transport belt 30, a paper storage unit 50 that stores the paper P on the paper supply side, and a pickup roll that picks up and transports the paper P stored in the paper storage unit 50 at a predetermined timing. 51 is provided. Further, on the sheet feeding side, a conveyance roll 52 that conveys the paper P fed by the pickup roll 51 and a registration roll 53 that sends the paper P to the paper conveyance belt 30 in accordance with the image forming operation are provided.
On the other hand, on the paper discharge side, a paper discharge roll 54 for conveying the paper P fixed by the fixing device 28 is disposed. A reversing roll 55 is provided on the paper discharge side. The reversing roll 55 discharges the paper P toward the discharge stacking portion 57 provided at the top of the apparatus main body 3 in the case of single-sided printing, and rotates in the reverse direction in the case of double-sided printing, thereby fixing the paper. The paper P on which one side is fixed by the device 28 is sent out toward the double-sided conveyance path M2. The double-sided conveyance path M2 is provided with a plurality of conveyance rolls 56 along the double-sided conveyance path M2.

  In the image forming apparatus 1 of the present embodiment, the image forming process unit 24 performs an image forming operation under the control of the control unit 22. Specifically, the image data input from the PC 5, the image reading device 6, or the like is subjected to predetermined image processing by the image processing unit 21 and is supplied to the laser exposure unit 20. For example, in the black (K) image forming unit 10 </ b> K, the surface of the photosensitive drum 11 uniformly charged at a predetermined potential by the charging roll 12 is converted into image data from the image processing unit 21 by the laser exposure unit 20. Based on this, scanning exposure is performed with the laser light whose lighting is controlled, and an electrostatic latent image is formed on the photosensitive drum 11. The formed electrostatic latent image is developed by the developing device 13, and a black (K) toner image is formed on the photosensitive drum 11. Similarly, in the image forming units 10Y, 10M, and 10C, yellow (Y), magenta (M), and cyan (C) toner images are formed.

On the other hand, when the formation of each color toner image in each image forming unit 10 is started, the paper P taken out from the paper storage unit 50 is supplied to the paper transport belt 30 by the registration roll 53 in accordance with the toner image formation timing. Is done. The surface of the paper transport belt 30 is charged to a predetermined potential by the suction roll 34. As a result, the paper P is electrostatically attracted onto the paper transport belt 30, and is transported along the paper transport path M1 by the paper transport belt 30 that circulates and moves in the direction of the arrow in FIG. In the middle of the process, the color toner images are sequentially transferred onto the paper P by the transfer electric field formed by the transfer roll 31.
Thereafter, the paper P on which each color toner image has been electrostatically transferred is peeled from the paper transport belt 30 downstream of the image forming unit 10 </ b> K and transported to the fixing device 28. When the paper P is conveyed to the fixing device 28, the unfixed toner image on the paper P is fixed to the paper P by receiving a fixing process using heat and pressure. The paper P on which the color toner images are fixed is stacked on a paper discharge stacking unit 57 provided in a discharge unit of the image forming apparatus 1. On the other hand, during double-sided printing, the same image forming operation is performed again via the double-sided conveyance path M2, and then the paper is stacked on the paper discharge stacking unit 57.

Further, the image forming apparatus 1 will be described.
FIG. 2 is a diagram illustrating the image forming apparatus 1 in a state where the cover 2 is opened.
As described above, the image forming apparatus 1 in this embodiment includes the cover 2 and the apparatus main body 3. The cover 2 is disposed so as to be openable and closable with respect to the apparatus main body 3 with a fulcrum 4 provided below as a center. In addition, a paper transport belt 30, a transfer roll 31, an idle roll 32, a drive roll 33, a suction roll 34, and the like are attached to the cover 2. For this reason, when the cover 2 is opened, as shown in the figure, the sheet conveyance belt 30, the transfer roll 31, the idle roll 32, and the like are in the state of accompanying the cover 2 side. As a result, when the cover 2 is opened, the image forming unit 10 is exposed, and the user or the like can access the paper transport path M1. Here, as described above, the image forming unit 10 is replaceably disposed in the apparatus main body 3, and is replaced in units of the image forming unit 10 when the toner in the developing device 13 is consumed. When the image forming unit 10 is replaced and the cover 2 is closed, each of the image forming units 10 is pressed by the transfer roll 31 via the paper conveying belt 30 and is disposed at a predetermined position of the apparatus main body 3. The Note that the image forming apparatus 1 according to the present embodiment includes a sensor (not shown) that performs a predetermined output when the cover 2 is closed.

Here, FIG. 3 and FIG. 4 are explanatory views showing the periphery of the paper transport belt 30 in detail.
In the image forming apparatus 1 according to the present embodiment, when a full color image is formed, that is, yellow (Y), magenta (M), cyan (C), and black (K), all the photosensitive members are used. It arrange | positions so that the drum 11 may be contacted. Further, when image formation is performed using the black (K) image forming unit 10K, that is, when a single color image is formed, the sheet conveying belt 30 is the photosensitive drum 11 in the image forming units 10Y, 10M, and 10C. It arrange | positions so that it may space apart from. Further, when image formation is performed using the image forming units 10Y, 10M, and 10C other than the black (K) image forming unit 10K, the sheet conveying belt 30 is separated from the photosensitive drum 11 in the image forming unit 10K. It is arranged.

  More specifically, as shown in FIG. 3, the image forming apparatus 1 (see FIG. 1) according to the present embodiment supports the transfer roll 31 k on the inner peripheral side of the paper transport belt 30 to be rotatable. A support portion 35a and a second support portion 35b that rotatably supports the transfer rolls 31y, 31m, and 31c are provided. Further, the first cam 38a that is rotatably arranged, the second cam 38b that is also rotatably arranged, and a drive source (non-rotating drive) that rotationally drives the first cam 38a and the second cam 38b. As shown). Further, a first coil spring 37a that presses the first support portion 35a toward the image forming unit 10 and a second coil spring 37b that presses the second support portion 35b toward the image forming unit 10 are provided. Yes. Further, a fulcrum 35c is provided that supports the first support part 35a and the second support part 35b in a rotatable (swingable) manner.

As described above, the first support portion 35a includes the defining roll 39a that rotatably supports the transfer roll 31k and that defines the traveling direction of the paper transport belt 30 that has passed through the transfer roll 31k. The first support portion 35a includes a through hole 35e in which the first cam 38a is disposed.
The second support portion 35b is disposed at a position facing the image forming units 10Y, 10M, and 10C with the paper transport belt 30 interposed therebetween. The second support portion 35b includes a through hole 35d between which the second cam 38b is disposed between the transfer roll 31y and the transfer roll 31m. Further, the second support portion 35 b includes a regulation roll 39 b that defines the traveling direction of the paper transport belt 30 that has passed through the drive roll 33, upstream of the transfer roll 31 y in the travel direction of the paper transport belt 30.

  In the present embodiment, when a single color image is formed using the image forming unit 10K, the second cam 38b is rotated clockwise in the drawing using a drive source (not shown), and the second coil spring 37b is used. The second support portion 35b is rotated clockwise in the figure against the pressing force. As a result, as shown in FIG. 4A, the sheet conveying belt 30 is separated from the photosensitive drum 11 in the image forming units 10Y, 10M, and 10C. When the sheet conveying belt 30 is separated from the photosensitive drum 11 in the image forming units 10Y, 10M, and 10C, the photosensitive drum 11 (photosensitive drum 11 in the image forming units 10Y, 10M, and 10C) is moved by the movement of the sheet conveying belt 30. The rotation of is stopped. When the sheet conveying belt 30 is brought into contact with the photosensitive drum 11 again, the second cam 38b is rotated counterclockwise in the drawing, and the second support 35b is moved by the second coil spring 37b in the drawing. Rotate counterclockwise.

  When image formation is performed using the image forming units 10Y, 10M, and 10C other than the image forming unit 10K, the first cam 38a is rotated counterclockwise in the drawing using a drive source (not shown). The first support portion 35a is rotated counterclockwise in the drawing against the pressing force of the first coil spring 37a. As a result, as shown in FIG. 4B, the sheet conveying belt 30 is separated from the photosensitive drum 11 in the image forming unit 10K. When the sheet conveying belt 30 is separated from the photosensitive drum 11 in the image forming unit 10K, the rotation of the photosensitive drum 11 (the photosensitive drum 11 in the image forming unit 10K) due to the movement of the sheet conveying belt 30 is stopped. When the paper transport belt 30 is brought into contact with the photosensitive drum 11 again, the first cam 38a is rotated clockwise in the drawing, and the first support 35a is moved by the first coil spring 37a to the clock shown in the drawing. Rotate around.

Here, the photosensitive drum 11 in the image forming unit 10 is rotated by a drive unit or the like provided in the apparatus main body 3 (see FIG. 1).
FIG. 5 is a perspective view showing one side of the image forming unit 10. As shown in the figure, in the present embodiment, a drive unit 40 that rotationally drives each photosensitive drum 11 in the image forming unit 10 is provided on one side of the image forming unit 10. Further, a switching unit 60 that transmits or does not transmit the driving force from the driving unit 40 to the photosensitive drum 11 is provided.

Each of the image forming units 10 according to the present exemplary embodiment is provided with photosensitive member side coupling members 18y and 18m as an example of a holding member side coupling member that is attached to the photosensitive drum 11 and rotates in conjunction with the photosensitive drum 11. , 18c, 18k (hereinafter also referred to as “photosensitive member side coupling member 18”).
On the other hand, the drive unit 40 is provided corresponding to each of the motor M3 and the photoconductor side coupling member 18 and is driven to rotate by the driving force generated by the motor M3. The drive side coupling members 43y, 43m, 43c, and 43k. (Hereinafter also referred to as “driving side coupling member 43”). Each of the drive side coupling members 43 is exposed in four grooves 62 formed in the housing 61 of the switching unit 60. Further, each of the drive side coupling members 43 is connected to the corresponding photoconductor side coupling member 18. As a result, each photosensitive drum 11 receives a driving force from the motor M3 and rotates.

FIG. 6 is a perspective view of the image forming unit 10 and the like as viewed from the drive unit 40 side.
As shown in the figure, the drive unit 40 in the present embodiment includes four shafts 42y, 42m, 42c, and 42k that are arranged adjacent to each other in the vertical direction and are rotatably arranged. In addition, four gears 41y, 41m, 41c, and 41k (hereinafter also referred to as “gear 41”) attached to each of the shafts 42y, 42m, 42c, and 42k are provided. These gears 41 are disposed in mesh with a transmission gear (not shown) that transmits the driving force from the motor M3, and are driven to rotate by receiving the driving force from the motor M3. As a result, the shafts 42y, 42m, 42c, and 42k are also rotationally driven.

On the other hand, the switching unit 60 includes a first drive gear 81 that is an example of a drive member that is rotatably arranged, and a second drive gear 82 that is an example of a drive member that is also rotatably arranged. Yes. Further, the switching unit 60 includes a motor (not shown) for rotating the first drive gear 81 and a motor (not shown) for rotating the second drive gear 82. Further, a first movable plate 83 disposed along the side surface of the housing 61 in the switching unit 60 and a second movable plate 84 disposed along the side surface of the housing 61 are provided.
The first movable plate 83 as an example of the first slide member includes a gear portion 83d that meshes with the first drive gear 81 on its side surface, and slides in the vertical direction by receiving the drive force from the first drive gear 81. The second movable plate 84 as an example of the second slide member also includes a gear portion 84e that meshes with the second drive gear 82 on its side surface, and slides in the vertical direction by receiving the drive force from the second drive gear 82. .

Here, the switching unit 60 will be described in more detail.
FIG. 7 is a perspective view showing the switching unit 60 and the like from the drive unit 40 side. In addition, illustration of the drive unit 40 (refer FIG. 6) is abbreviate | omitted in this figure.
Although the details will be described later, the switching unit 60 is linked to the first movable plate 83 and the second movable plate 84, and moves forward and backward with respect to the photosensitive member side coupling member 18 (four advance / retreat members 70y, 70m, 70c, 70k). , Also referred to as “advance / retreat member 70”). Each of the advancing and retracting members 70 is rotatable in four accommodating portions 63y, 63m, 63c, and 63k (hereinafter also referred to as “accommodating portions 63”) arranged in parallel in the vertical direction on the side portion of the housing 61. Is housed in. Further, the switching unit 60 includes a guide (not shown) that defines the sliding direction of the first movable plate 83 and the second movable plate 84 on the side. In the present embodiment, the first drive gear 81, the first movable plate 83, the advance / retreat members 70y, 70m, 70c, etc. function as an example of the first coupling mechanism, and the second drive gear 82, the second movable plate 84, the advance / retreat member 70k and the like function as an example of the second coupling mechanism. In the present embodiment, the first drive gear 81, the second drive gear 82, the first movable plate 83, the second movable plate 84, the advance / retreat member 70, and the like function as an example of an operation mechanism and a connection release mechanism. . The advance / retreat members 70y, 70m, and 70c function as an example of the first advance / retreat member, and the advance / retreat member 70k functions as an example of the second advance / retreat member.

Further, the advance / retreat member 70 and the like will be described in detail.
Here, FIG. 8 is a perspective view when the first movable plate 83, the second movable plate 84, and the advance / retreat member 70 are viewed from the image forming unit 10 side.
As shown in the figure, each of the advancing and retracting members 70 includes a ring portion 70a having a through hole in the center and formed in a ring shape, an arm portion 70b protruding outward from the ring portion 70a, and a tip portion of the arm portion 70b. And a through hole 70d formed in the shape of a long hole. Further, each of the advancing and retracting members 70 is arranged to be aligned on the second movable plate 84 side.
On the other hand, the second movable plate 84 is formed in an elongated shape and a thin plate shape, and protrudes toward the image forming unit 10 side on the side surface and the upper end portion on the image forming unit 10 side (see FIG. 7). Is provided with a protruding portion 84a penetratingly disposed on the surface. Further, the above-described gear portion 84e that meshes with the second drive gear 82 (see FIG. 7) is provided on one side surface and the lower end portion.

  In addition, the second movable plate 84 includes an upper elongated hole 84b as an example of a through hole that is provided through the lower portion of the projecting portion 84a and is formed along the sliding direction of the first movable plate 83. . Further, below the upper elongated hole 84b, there is provided a middle elongated hole 84c as an example of a through hole which is also provided and is formed along the sliding direction of the first movable plate 83. In addition, a lower elongated hole 84d as an example of a through hole that is also provided through and is formed along the sliding direction of the first movable plate 83 is provided below the middle elongated hole 84c and above the gear portion 84e. Yes.

  As with the second movable plate 84, the first movable plate 83 is formed in a long shape and a thin plate shape. The first movable plate 83 is disposed closer to the drive unit 40 (see FIG. 6) than the second movable plate 84 and is disposed so as to overlap the second movable plate 84. The first movable plate 83 is disposed so as to slide in the sliding direction of the second movable plate 84.

  The first movable plate 83 includes a first projecting portion 83a that is provided on the surface facing the second movable plate 84 and at the upper end thereof so as to pass through the upper long hole 84b and the through hole 70d of the advance / retreat member 70c. ing. Further, below the first protrusion 83a, there is provided a second protrusion 83b penetratingly disposed in the middle elongated hole 84c and the through hole 70d of the advance / retreat member 70m. Further, below the second projecting portion 83b, there is provided a third projecting portion 83c penetratingly disposed in the lower elongated hole 84d and the through hole 70d in the advance / retreat member 70y.

  This figure shows a state in which the first movable plate 83 and the second movable plate 84 are positioned below the switching unit 60 (see also FIG. 7) (hereinafter, this state is referred to as a “first state”). . In this first state, the first protrusion 83a is at the center in the longitudinal direction of the upper elongated hole 84b, the second protrusion 83b is at the center in the longitudinal direction of the middle elongated hole 84c, and the third protrusion 83c is at the bottom. It is located in the longitudinal center of the long hole 84d. Further, as a result of the first projecting portion 83a, the second projecting portion 83b, and the third projecting portion 83c being positioned in this way, the arm portions 70b of the advance / retreat members 70c, 70m, and 70y are in a state of facing obliquely downward. (See also FIG. 7). Furthermore, the arm part 70b in the advance / retreat member 70k is also directed obliquely downward.

Here, FIG. 9 is a diagram showing the inside of the switching unit 60 in the first state.
As described above, the switching unit 60 according to the present embodiment includes the four accommodating portions 63y, 63m, 63c, and 63k that accommodate the advance / retreat members 70y, 70m, 70c, and 70k in the housing 61. In the present embodiment, drive side coupling members 43y, 43m, 43c, and 43k are disposed inside the accommodating portion 63.

  Each drive side coupling member 43 is attached to the shafts 42y, 42m, 42c, and 42k, and is pressed toward each photoconductor side coupling member 18 by a coil spring (not shown). Thereby, each drive side coupling member 43 is connected to the corresponding photoconductor side coupling member 18. In the first state, as shown in this figure, all the drive side coupling members 43 are connected to the photoconductor side coupling member 18 (an example of the third mode), and all the photoconductor drums 11 are connected. Is driven to rotate. Therefore, in the first state, image formation using all the image forming units 10, that is, full-color image formation is possible. In the present embodiment, the shaft 42, the drive side coupling member 43, and the photoconductor side coupling member 18 corresponding to each photoconductor drum 11 function as each rotation drive mechanism. In the present embodiment, the driving side coupling members 43y, 43m, and 43c function as a first group of driving side coupling members, and the driving side coupling member 43k functions as a second group of driving side coupling members. is doing. The drive side coupling members constituting each group are not limited to a plurality, and may be constituted by a single drive side coupling member, such as the drive side coupling member 43k constituting the second group.

Further, the internal configuration of the switching unit 60 and the like will be described.
FIG. 10 is an enlarged view of the periphery of the drive side coupling member 43c in FIG.
When the periphery of the drive side coupling member 43c is described as an example, the drive unit 40 in the present embodiment is provided with projecting pins 44 that penetrate through the shaft 42c and project at both ends from the outer peripheral surface of the shaft 42c. The protruding pin 44 is disposed inside the driving side coupling member 43c, and is formed inside the driving side coupling member 43c when the shaft 42c is driven to rotate by the motor M3 (see FIG. 5). It is arrange | positioned so that it may contact | abut to the abutting surface 45 made. As a result, the drive side coupling member 43c also rotates in conjunction with the rotation of the shaft 42c.

  The drive side coupling member 43c is slidably disposed along the axial direction of the shaft 42c. More specifically, the drive side coupling member 43c in the present embodiment has a shaft 42c disposed therein and is formed with a larger diameter than the shaft 42c, and is directed from the drive unit 40 side toward the image forming unit 10C side. A through hole 46 is provided. Further, the drive side coupling member 43c includes the abutting surface 45 as described above. The abutting surface 45 is formed in a flat shape and is disposed along the axial direction of the shaft 42c. The drive side coupling member 43c includes an inward protruding portion 47 that protrudes into the through hole 46 on the photosensitive member side coupling member 18c side. The inward protruding portion 47 abuts against the tip end portion of the shaft 42c when the driving side coupling member 43c slides toward the driving unit 40.

Further, the driving side coupling member 43c is formed closer to the photoconductor side coupling member 18c than the abutting surface 45, from the through hole 46 toward the outer side of the driving side coupling member 43c, and the shaft 42c. A concave groove 48 is provided so as to surround the outer peripheral surface of the first groove. When the drive side coupling member 43c slides toward the drive unit 40 and the inward protruding portion 47 hits the tip end portion of the shaft 42c, the protruding pin 44 is disposed in the recessed groove 48 in a rotatable state. . Further, the drive side coupling member 43c is provided with an outward projecting portion 49 projecting outward on the outer peripheral portion thereof.
On the other hand, the advancing / retreating member 70c in the present embodiment includes an inward protruding portion 70e protruding inward on the inner peripheral surface of the ring portion 70a.

The driving side coupling member 43c in the present embodiment is disposed inside the ring portion 70a. As a result of being pressed by the coil spring (not shown), the outward projecting portion 49 is abutted against the inwardly projecting portion 70 e and the advance / retreat member 70 c is abutted against the housing 61. As a result, the drive side coupling member 43c is positioned at a predetermined position in the accommodating portion 63c. Further, the front end portion of the drive side coupling member 43c is exposed from the advance / retreat member 70c, and the front end portion is coupled to the photoconductor side coupling member 18c.
Note that the drive side coupling member 43c in the present embodiment is configured by assembling two members, a connection member 19a connected to the photoconductor side coupling member 18c, and a support member 19b that supports the connection member 19a.

FIG. 11 is a diagram schematically showing the switching unit 60 and the like.
Here, FIG. 11A schematically shows the switching unit 60 and the like in the first state. In the drawing, the illustration of the charging roll 12 and the drum cleaner 14 (see FIG. 1) provided in the image forming unit 10 and the illustration of the drive unit 40 (see FIG. 6) and the like are omitted. In this figure, the photosensitive drums 11 provided in the image forming units 10Y, 10M, 10C, and 10K are indicated as 11y, 11m, 11c, and 11k, respectively.

In the first state shown in FIG. 11A, when the first drive gear 81 is rotationally driven in the direction indicated by the arrow A in the figure, the first movable plate 83 receives the drive force from the first drive gear 81. , Slide upwards. As a result, the first projecting portion 83a, the second projecting portion 83b, and the third projecting portion 83c formed on the first movable plate 83 are directed upward in the upper elongated hole 84b and upward in the middle elongated hole 84c. The lower elongated holes 84d are moved upward. Further, as the first projecting portion 83a, the second projecting portion 83b, and the third projecting portion 83c move upward, each of the advance / retreat members 70y, 70m, 70c is driven in a lump, and is in the direction of arrow B in the figure. Rotate to.
When the upward sliding of the first movable plate 83 is completed, as shown in FIG. 11B, the first projecting portion 83a is located above the upper elongated hole 84b, and the second projecting portion 83b is defined as the middle elongated hole 84c. At the upper part, the third protrusion 83c is located above the lower elongated hole 84d. Further, the arm portions 70b (see FIG. 8) of the advance / retreat members 70y, 70m, and 70c are inclined upward (hereinafter, this state is referred to as “second state”).

Here, FIG. 12 is a diagram showing the inside of the accommodating portion 63c in the second state. In addition, although the accommodating part 63c is demonstrated as an example, in this 2nd state, the accommodating parts 63m and 63y are also in the same state as the accommodating part 63c.
Although the description is omitted in FIG. 10, the switching unit 60 according to the present embodiment includes a guide protrusion 66 that is disposed to protrude inward and is formed in a spiral shape on the inner wall of the housing portion 63 c. When the first movable plate 83 slides upward as described above and the advance / retreat member 70c rotates, the advance / retreat member 70c is guided by the guide projection 66 and moves away from the photoconductor side coupling member 18c ( fall back). When the advance / retreat member 70c moves in a direction away from the photoconductor side coupling member 18c, the drive side coupling member 43c also moves (slides) in a direction away from the photoconductor side coupling member 18c.

  As a result, in the second state, as shown in FIG. 12, the connection between the photoconductor side coupling member 18c and the drive side coupling member 43c is released. For this reason, the rotation of the photosensitive drum 11c (see FIG. 11) by the driving side coupling member 43c is stopped. In the second state, the projecting pin 44 is positioned in the concave groove 48, so that the rotation of the drive side coupling member 43c is also stopped. In the second state, as shown in FIG. 4A, the sheet conveying belt 30 is separated from the photosensitive drum 11 in the image forming units 10Y, 10M, and 10C. For this reason, the rotation of the photosensitive drum 11 (the photosensitive drum 11 in the image forming units 10Y, 10M, and 10C) by the paper transport belt 30 is also stopped. That is, in the present embodiment, when the first movable plate 83 slides upward by the rotational drive of the first drive gear 81, the rotational drive of the photosensitive drum 11 in the image forming units 10Y, 10M, and 10C is stopped.

  By the way, when moving from the first state to the second state, the advance / retreat member 70k is not rotated (see FIGS. 11A and 11B). Therefore, in the second state, the connection between the photoconductor side coupling member 18k and the drive side coupling member 43k (see FIG. 9) is maintained, and the photoconductor side coupling members 18y, 18m, 18c and the drive side cup are connected. The connection with the ring members 43y, 43m, 43c (see FIG. 9) is released (an example of the first mode). As a result, in the second state, only the photosensitive drum 11k in the image forming unit 10K is rotationally driven, and image formation using the image forming unit 10K, that is, single color (K color) image formation is possible. In the second state, as described above, the rotational drive of the photosensitive drum 11 (photosensitive drums 11y, 11m, and 11c) in the image forming units 10Y, 10M, and 10C is stopped. For this reason, it is possible to suppress wear of the photosensitive drums 11y, 11m, and 11c, wear of the drum cleaner 14, and the like. If the first drive gear 81 is rotated in the direction opposite to the direction indicated by the arrow A (see FIG. 11A) (the other direction) in the state of FIG. 18y, 18m, and 18c and the drive side coupling members 43y, 43m, and 43c are connected again, and a full-color image can be formed.

Next, an operation when the second drive gear 82 and the like are rotationally driven will be described.
Here, FIG. 13 is a diagram for explaining an operation when the second drive gear 82 and the like are rotationally driven.
As shown in FIG. 13A, when the second drive gear 82 is rotationally driven in the direction of arrow C in the figure, the second movable plate 84 receives the drive force from the second drive gear 82 and moves upward in the figure. Slide to. For this reason, the protrusion part 84a formed in the 2nd movable plate 84 also moves upwards. Further, with the upward movement of the protruding portion 84a, the advance / retreat member 70k rotates in the direction indicated by the arrow D in the figure. As a result, as shown in the figure, the first projecting portion 83a is located below the upper elongated hole 84b, the second projecting portion 83b is located below the middle elongated hole 84c, and the third projecting portion 83c is located below the lower elongated hole 84d. , Each located. Further, the arm portion 70b (see FIG. 8) of the advance / retreat member 70k is in a state of facing obliquely upward in the drawing (hereinafter, this state is referred to as a “third state”).

  In the third state, the advancing / retracting members 70y, 70m, and 70c do not rotate, and only the rotating member 70k rotates, so that the photoconductor side coupling member 18k and the driving side coupling member 43k (see FIG. 9) are connected. Only the state is released (an example of the second mode). For this reason, the rotation of the photosensitive drum 11k by the driving side coupling member 43k is stopped. In the third state, as shown in FIG. 4B, the sheet conveying belt 30 is separated from the photosensitive drum 11 (photosensitive drum 11k) in the image forming unit 10K. For this reason, the rotation of the photosensitive drum 11k by the paper transport belt 30 is also stopped. That is, in the present embodiment, when the second movable plate 84 slides upward by the rotation drive of the second drive gear 82, the rotation drive of the photosensitive drum 11k is stopped. On the other hand, in the third state, the connection between the photoconductor side coupling members 18y, 18m, and 18c and the drive side coupling members 43y, 43m, and 43c is maintained. For this reason, in the third state, only the photosensitive drum 11 in the image forming units 10Y, 10M, and 10C is rotationally driven, and image formation using the image forming units 10Y, 10M, and 10C becomes possible.

  Here, since the toner of K color generally has a large consumption, it may be consumed before the other colors. Further, the image forming unit 10K may not function due to a failure of the developing device 13 or the like. Furthermore, the convenience of the image forming apparatus can be enhanced if K color image formation is possible without purchasing the image forming unit 10K. Therefore, the image forming apparatus 1 according to the present embodiment has a configuration capable of forming so-called process black by superimposing Y, M, and C color toners using the image forming units 10Y, 10M, and 10C. .

  By the way, when forming process black, if the photosensitive drum 11k is in a rotationally driven state, the photosensitive drum 11k is worn even though it is not used. Further, the wear of the drum cleaner 14 (see FIG. 1) disposed in contact with the photosensitive drum 11k also progresses. Therefore, in the present embodiment, as described above, the connection between the driving side coupling member 43k and the photosensitive member side coupling member 18k can be released, and the sheet conveying belt 30 can be separated from the photosensitive drum 11k. When image formation is performed with process black, the photosensitive drum 11k is not rotationally driven. In particular, when the toner supply unit and the photosensitive drum are separated and the toner is consumed up, the toner supply unit is replaced and the photosensitive drum is continuously used. There is a request to suppress the progress of. In the state shown in FIG. 13A, if the second drive gear 82 is driven to rotate in the direction opposite to the direction indicated by the arrow C (the other direction), the photosensitive member side coupling member 18k and the drive side coupling are coupled. The member 43k is connected again, and a full-color image can be formed.

Here, when both the first drive gear 81 and the second drive gear 82 are driven to rotate, as shown in FIG. 13B, both the first movable plate 83 and the second movable plate 84 slide upward. . As a result, all the connections between the photoconductor side coupling member 18 and the drive side coupling member 43 are released.
Note that the first drive gear 81 and the second drive gear 82 in the present embodiment are configured to rotate in conjunction with the opening operation of the cover 2.

FIG. 14 is a diagram for explaining the relationship between the cover 2 and the switching unit 60 and the like. 14A is a view showing the side portion of the switching unit 60 and the like, and FIG. 14B shows the first gear 87 and the like from the X direction in FIG. 14A. . In FIG. 14A, the cover 2 is shown in a simplified manner.
As described above, in this embodiment, the first drive gear 81 that meshes with the gear portion 83d provided on the first movable plate 83 and the second drive gear 82 that meshes with the gear portion 84e provided on the second movable plate 84 are arranged. It is installed. Further, in the present embodiment, the first gear 87 that is rotatably arranged, the second gear 88 that is also rotatably arranged, and the driving force from the second gear 88 are applied to the second drive gear 82. A third gear 89 for transmission and a rotation mechanism 90 for rotating the first gear 87 and the second gear 88 when the cover 2 is opened are disposed.

When the cover 2 is opened, the first gear 87 is engaged with a rack gear member 93 provided in the rotation mechanism 90 and rotates in conjunction with the opening operation of the cover 2. Details of the rotation mechanism 90 will be described later. The driving force generated in the first gear 87 by opening the cover 2 is transmitted to the first driving gear 81 by a transmission gear (not shown).
When the cover 2 is opened, the second gear 88 is engaged with a rack gear member 93 provided in the rotation mechanism 90 and is driven to rotate in conjunction with the opening operation of the cover 2. Then, the driving force generated in the second gear 88 by opening the cover 2 is transmitted to the second driving gear 82 via the third gear 89.

Here, FIG. 15 is a diagram for explaining the rotation mechanism 90. 15A is a perspective view showing the rotation mechanism 90 including the cover 2, and FIG. 15B is a side view of the rotation mechanism 90. In FIG. 15B, the cover 2 and the interlocking arm 2a are not shown, and the third movable plate 92 is simplified and displayed.
The rotation mechanism 90 in the present embodiment includes an interlocking arm 2a having one end attached to the back of the cover 2 and moving in conjunction with the opening / closing operation of the cover 2, and a penetrating shaft penetratingly provided at the other end of the interlocking arm 2a. 2b. The rotation mechanism 90 is attached to the lower side of the third movable plate 92, the third movable plate 92 slidably disposed, the guide member 91 that guides the third movable plate 92, and the cover 2 is opened. In this case, a rack gear member 93 that meshes with the first gear 87 and the second gear 88 is provided. Further, the rotation mechanism 90 includes a coil spring 94 that urges the third movable plate 92 toward one end portion side (the left side in the drawing) of the guide member 91.

  Two guide members 91 in the present embodiment are disposed on both sides of the interlocking arm 2a. The guide member 91 is fixed to the apparatus main body 3 (see FIG. 1) side. Each of the guide members 91 is formed in a long and plate shape, and is fixed to the apparatus main body 3 side. The guide main body 91a is provided through the guide main body 91a and extends in the longitudinal direction of the guide main body 91a. A guide-side elongated hole 91b formed so as to surround the guide-side elongated hole 91b and for defining the sliding direction of the third movable plate 92.

  On the other hand, two third movable plates 92 are disposed on both sides of the interlocking arm 2a, like the guide member 91. The third movable plate 92 is disposed between the interlocking arm 2a and the guide member 91. Each of the third movable plates 92 is formed in a plate-like main body portion 92a formed in a long and plate shape, and is formed along the longitudinal direction of the plate-side main body portion 92a so as to penetrate the plate-side main body portion 92a. And a plate-side long hole 92b. A penetration shaft 2b is disposed inside the plate-side long hole 92b. Further, the total length L2 of the plate side long hole 92b is formed to be smaller than the total length L1 of the guide side long hole 91b.

  Further, each of the third movable plates 92 includes a plate-side protruding portion 92c formed so as to surround the plate-side long hole 92b and disposed so as to protrude into the guide-side long hole 91b. The plate-side protrusion 92c is disposed so as to contact the guide-side protrusion 91c, and defines the sliding direction of the third movable plate 92 together with the guide-side protrusion 91c.

The rack gear member 93 is disposed so as to straddle both the plate-side main body portions 92a, and is fixed to the lower edge portion of the plate-side main body portion 92a. The rack gear member 93 slides in conjunction with the cover 2 when the cover 2 is opened, and meshes with the first gear 87 and the second gear 88 to rotate the first gear 87 and the second gear 88.
When the first gear 87 and the second gear 88 are engaged with the rack gear member 93 in a state where the cover 2 is closed, the rotation of the first gear 87 and the second gear 88 is restricted by the rack gear member 93. . In such a case, the rotational drive of the first drive gear 81 and the second drive gear 82 (see FIG. 14) is also restricted, and the upward sliding of the first movable plate 83 described with reference to FIG. It becomes difficult to slide the second movable plate 84 described above in FIG. Therefore, in the present embodiment, the first gear 87 and the second gear 88 are configured not to mesh with the rack gear member 93 when the cover 2 is closed.

  Here, for example, when full-color image formation is completed, the third movable plate 92 is positioned on the left side of the guide member 91 in the drawing as shown in FIGS. 14, 15 </ b> A, and 15 </ b> B. At the same time, the penetrating shaft 2b is disposed at the center in the longitudinal direction of the plate side long hole 92b. When the cover 2 is opened from this state, the penetrating shaft 2b moves in the direction indicated by the arrow F in the figure in conjunction with the interlocking arm 2a. Hereinafter, the operation of the rotation mechanism 90 will be described in detail.

FIG. 16 is a diagram for explaining the operation of the rotation mechanism 90. FIG. 16 (a) shows the same state as FIG. 15 (b).
When the cover 2 (see FIG. 15A) is opened in the state of FIG. 16A, the interlocking arm 2a also moves in conjunction with the cover 2. As a result, as shown by the arrow F in the figure, the through shaft 2b moves in the direction of the right end of the plate-side long hole 92b. When the cover 2 is further opened, the penetrating shaft 2b hits the plate-side main body 92a at the right end of the plate-side elongated hole 92b, and the third movable plate 92 starts to move to the right in the drawing. .

  Then, when the third movable plate 92 starts to move to the right and the third movable plate 92 reaches a predetermined position, the rack gear member 93 and the first gear 87 are engaged as shown in FIG. The meshing between the rack gear member 93 and the second gear 88 is started. As a result, the first gear 87 and the second gear 88 start to rotate in the direction indicated by the arrow H in the drawing. When rotation of the first gear 87 and the second gear 88 is started, the first drive gear 81 and the second drive gear are transmitted via a transmission gear (not shown) and a third gear 89 (see FIG. 14A). The driving force is transmitted to 82, and the rotational driving of the first driving gear 81 and the second driving gear 82 is started. As a result, the upward sliding of the first movable plate 83 and the second movable plate 84 (see FIG. 13B) is started.

When the cover 2 is completely opened, the third movable plate 92 is positioned on the right side of the guide member 91 and the first movable plate 83 and the second movable plate 84 are moved as shown in FIG. The upward slide is completed.
When the closing operation of the cover 2 is started from the state shown in FIG. 16C, the through shaft 2b moves in the direction indicated by the arrow J in the plate side through the long hole 92b. When the cover 2 is completely closed, the through shaft 2b is disposed at the left end of the plate-side long hole 92b as shown in FIG.

In addition, the rotation mechanism 90 in the present embodiment is configured such that when the cover 2 is closed, the penetrating shaft 2b does not hit the plate-side main body 92a. As a result, the third movable plate 92 is not slid by the closing operation of the cover 2. For this reason, depending on the closing operation of the cover 2, the first gear 87 and the second gear 88 are not rotationally driven, and the first movable plate 83 and the second movable plate 84 are not slid downward.
Then, the first drive gear 81 and the second drive gear 82 (see FIG. 14A) are rotated by a drive source (not shown), and as shown in FIG. 16D, the first gear 87 and the second gear are driven. When 88 is rotated in the direction indicated by arrow M in the figure, the third movable plate 92 starts to slide to the left (see arrow N in the figure). When the first gear 87 and the second gear 88 are rotated by a predetermined amount and the third movable plate 92 reaches a predetermined position, the rack gear member 93 and the first gear 87 are engaged, and the rack gear member 93 and the second gear 88 are engaged. Is released. Thereafter, the third movable plate 92 slides to the left by the coil spring 94 and is disposed on the left side of the guide member 91. As a result, the rotation mechanism 90 is in the initial state as shown in FIGS.

In the present embodiment, when the first gear 87 and the second gear 88 are rotationally driven in the direction indicated by the arrow M in FIG. 16D, the first gear 87 and the second gear 88 when the cover 2 is opened. The first gear 87 and the second gear 88 are rotationally driven by a larger amount than the rotational drive amount. Thereby, the meshing between the rack gear member 93 and the first gear 87 and the like can be reliably released.
However, in this case, since the rotation amount of the first drive gear 81 and the second drive gear 82 (see FIG. 14A) also needs to be larger than the rotation amount when the cover 2 is opened, the first movable gear The plate 83 and the second movable plate 84 are positioned below the position (see FIG. 14A) before the cover 2 is opened. For this reason, in this embodiment, it is set as the structure which detects the position of the 1st movable plate 83 and the 2nd movable plate 84 with a sensor not shown. Then, after the meshing between the rack gear member 93 and the first gear 87 is released, the first drive gear 81 and the second drive gear 82 are driven to rotate based on the output from the sensor, and the first movable plate 83 and the first gear 83 2 The process which returns the movable plate 84 to a predetermined position is performed. By this processing, the first movable plate 83 and the second movable plate 84 slide upward and return to the position before the cover 2 is opened.

Here, the operation of the advance / retreat member 70 and the like when the cover 2 is opened and closed will be described with reference to FIG.
FIG. 17 shows a side portion of the switching unit 60 in which the rotation mechanism 90 is in the state of FIG. When opening of the cover 2 is started, as described with reference to FIG. 16A, the through shaft 2b moves toward the right end portion of the plate-side long hole 92b. When the third movable plate 92 starts to move to the right and the third movable plate 92 reaches a predetermined position, the rack gear member 93 and the first gear 87 are engaged, and the rack gear member 93 and the second gear 88 are engaged. Engagement with is started. As a result, the rotation mechanism 90 and the like are in the state shown in FIGS.

  Then, when the cover 2 is further opened from the state shown in FIG. 17, the first gear 87 and the second gear 88 are rotationally driven in the direction indicated by the arrow H in the figure as described with reference to FIG. . As a result, as shown in FIG. 17, the first drive gear 81 and the second drive gear 82 start to rotate in the direction indicated by the arrow P in the figure. For this reason, upward sliding of the first movable plate 83 and the second movable plate 84 is also started. Further, as the first movable plate 83 and the second movable plate 84 start to slide upward, each advance / retreat member 70 starts to rotate in the direction indicated by the arrow Q in the drawing.

Here, FIG. 18 shows a state after the opening of the cover 2 is completed.
When the opening of the cover 2 is finished, the rotating mechanism 90 is in the state shown in FIG. 16C, and the upward sliding of the first movable plate 83 and the second movable plate 84 is also finished. Then, when the upward sliding of the first movable plate 83 and the second movable plate 84 is completed, the rotation of each advance / retreat member 70 is also completed, and the arm portion 70b is directed obliquely upward as shown in FIG. .
As a result, all of the drive side coupling member 43 (see FIG. 9) slides toward the drive unit 40, and the connection between the drive side coupling member 43 and the photoconductor side coupling member 18 is completely released. When the opening of the cover 2 is completed, the image forming unit 10 is exposed as shown in FIG. Therefore, the image forming unit 10 can be replaced by the user or the like by opening the cover 2.

  The above operation is the operation when the cover 2 is opened after the image formation in the full color mode is completed, but the image formation in the monochrome mode is completed (see FIG. 11B). 2), the second movable plate 84 slides upward by the second drive gear 82, and the connection between the drive side coupling member 43k and the photoconductor side coupling member 18k is released. . When the cover 2 is opened, the first movable plate 83 also starts to slide upward by the first drive gear 81. When the cover 2 is slid by a predetermined amount, the first drive gear 81 and the gear portion 83d (see FIG. 6). ) Is released. For this reason, the 1st movable plate 83 will remain in a predetermined position.

  Further, when the cover 2 is opened from the state where the image formation is completed in the process black (FIG. 13A), the first movable plate 83 is slid upward by the first drive gear 81, and the drive side The coupling between the coupling members 43y, 43m, and 43c and the photoconductor side coupling members 18y, 18m, and 18c is released. When the cover 2 is opened, the second movable plate 84 also starts to slide upward by the second drive gear 82, but when the cover 2 is slid by a predetermined amount, the second drive gear 82 and the gear portion 84e (see FIG. 6). ) Is released. For this reason, the second movable plate 84 stays at a predetermined position.

  When the image forming unit 10 is replaced or the like and the cover 2 is closed, the rotation mechanism 90 is in the state shown in FIG. 16D, and the side portion of the switching unit 60 is in the state shown in FIG. As described with reference to FIG. 16D, when the cover 2 is closed, the third movable plate 92 is not slid, and the first drive gear 81, the second drive gear 82, and the like are also rotated. Not done. As a result, since the advance / retreat member 70 is not rotated, even if the cover 2 is closed, the drive side coupling member 43 and the photoconductor side coupling member 18 are not connected and remain released. It becomes.

  When the cover 2 is completely closed and a predetermined output is output from a sensor (not shown), the first drive gear 81 and the second drive gear 82 are driven to rotate in the direction indicated by the arrow R in the figure by a motor (not shown). . When the first drive gear 81 and the second drive gear 82 start to rotate, the first movable plate 83 and the second movable plate 84 start to slide downward, and the drawings of the respective advancing and retracting members 70 are shown. The rotation in the direction indicated by the middle arrow S is also started.

  Further, when the rotational drive of the first drive gear 81 and the second drive gear 82 is started, the direction indicated by the arrow M in the drawing of the first gear 87 and the second gear 88 as shown in FIG. Starts rotating. As a result, the movement of the third movable plate 92 in the direction indicated by the arrow N in the drawing is started. Thereafter, the meshing between the rack gear member 93 and the first gear 87 and the meshing between the rack gear member 93 and the second gear 88 are released, and the third movable plate 92 is moved on the left side of the guide member 91 by the coil spring 94. It is arranged at a predetermined position.

FIG. 20 shows a state after the rotational drive of the first drive gear 81 and the second drive gear 82 is completed.
When the rotation drive of the first drive gear 81 and the second drive gear 82 is finished and the first movable plate 83 and the second movable plate 84 are arranged at predetermined positions, the rotation of each advance / retreat member 70 is also finished and the arm portion 70b. Is in a state of facing diagonally downward. As a result, as shown in FIG. 9, the photoconductor side coupling member 18 and the drive side coupling member 43 are all connected, and an image can be formed.
Although the present embodiment has been described with the configuration having four image forming units 10, the present invention can also be applied to a configuration having five or more image forming units 10. For example, in a configuration in which spot colors are added to Y, M, C, and K, a mode that prints only spot colors, a mode that uses Y, M, C, and K, and Y, M, C, and K and spot colors are used. To print mode. In this embodiment, the image forming apparatus 1 using the paper direct conveyance belt has been described as an example. However, the image forming apparatus using the intermediate transfer member can also be diverted.

1 is a diagram illustrating an overall configuration of an image forming apparatus to which the present invention is applied. 1 is a diagram illustrating an image forming apparatus in a state where a cover is open. FIG. 4 is an explanatory diagram illustrating in detail the periphery of a paper transport belt. FIG. 4 is an explanatory diagram illustrating in detail the periphery of a paper transport belt. FIG. 3 is a perspective view showing one side of the image forming unit. It is the perspective view which looked at the image forming unit etc. from the drive unit side. It is the perspective view which showed the switching unit etc. from the drive unit side. It is a perspective view at the time of seeing the 1st movable plate, the 2nd movable plate, and the advance / retreat member from the image forming unit side. It is the figure which showed the inside of the switching unit in a 1st state. FIG. 10 is an enlarged view of the periphery of a drive side coupling member in FIG. 9. It is the figure which showed the switching unit etc. typically. It is the figure which showed the inside of the accommodating part in a 2nd state. It is a figure for demonstrating the operation | movement at the time of rotationally driving a 2nd drive gear. It is a figure for demonstrating the relationship between a cover, a switching unit, etc. FIG. It is a figure for demonstrating a rotation mechanism. It is a figure for demonstrating operation | movement of a rotation mechanism. FIG. 17 shows the side of the switching unit in which the rotation mechanism is in the state of FIG. A state after the opening of the cover is completed is shown. It is the figure which showed the side part of the switching unit. The state after the rotational drive of the 1st drive gear and the 2nd drive gear is completed is shown.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Image forming apparatus, 2 ... Cover, 3 ... Apparatus main body, 11 ... Photoconductor drum, 18y, 18m, 18c, 18k ... Photoconductor side coupling member, 30 ... Paper conveyance belt, 43y, 43m, 43c, 43k ... Drive Side coupling member, 70y, 70m, 70c, 70k ... advance / retreat member, 81 ... first drive gear, 82 ... second drive gear, 83 ... first movable plate, 84 ... second movable plate, 84b ... upper elongated hole, 84c ... Middle hole, 84d ... Lower hole, M3 ... Motor

Claims (13)

A plurality of image carriers that are rotatably arranged and hold toner images;
Wherein the plurality of provided corresponding to each of the image carrier of the image carrier Rutotomoni, rotatably provided around a rotation axis along the axial direction of the image carrier, and, the image carrier coaxially A plurality of holding body side coupling members provided on the image holding body and capable of transmitting a driving force to the image holding body;
Wherein the plurality of holder side coupling member each provided corresponding to the Rutotomoni rotatably provided around a rotation axis along the axial direction of the holding side coupling member, and, the holding side coupling member and provided coaxially, a plurality of drive-side coupling member for rotationally driving the image carrier via the holding side coupling member by being connected to the holding side coupling member,
The first group of driving side coupling members among the plurality of driving side coupling members is advanced and retracted along the axial direction of the driving side coupling member, and the first group of driving side coupling members corresponds to the first group of driving side coupling members. A first connecting mechanism for connecting / disconnecting the holding body side coupling member;
A second group of driving side coupling members among the plurality of driving side coupling members is advanced and retracted along the axial direction of the driving side coupling member, and the second group of driving side coupling members corresponds to the second group of driving side coupling members. A second coupling mechanism that performs coupling / decoupling with the holding body side coupling member,
The first mode in which the connection is released by the first connection mechanism and the connection is made by the second connection mechanism, and the connection is made by the first connection mechanism and the connection is released by the second connection mechanism. An image forming apparatus having a second mode. The drive side coupling member of at least one of the first group of drive side coupling members and the second group of drive side coupling members includes a plurality of drive side coupling members,
A slide member provided so as to be slidable in a predetermined direction, and further provided to interlock with the plurality of drive side coupling members;
2. The image forming apparatus according to claim 1, wherein the advancing and retreating of the plurality of drive side coupling members along the axial direction is performed in a lump as the slide member slides. The advancing and retreating along the axial direction of the driving side coupling member included in the driving side coupling member of the other group among the driving side coupling member of the first group and the driving side coupling member of the second group. The image forming apparatus according to claim 2, wherein the image forming apparatus is configured to slide the second slide member provided so as to be interlocked with the driving side coupling member in a predetermined direction. The second slide member provided so as to be interlocked with the driving side coupling member included in the driving group coupling member of the other group includes the plurality of the second slide members included in the driving side coupling member of the one group. The sliding member is provided so as to slide along a sliding direction of the slide member provided so as to be interlocked with the drive side coupling member, and is provided in a state of being superimposed on the slide member. Item 4. The image forming apparatus according to Item 3.   The image forming apparatus according to claim 1, further comprising a third mode in which the connection is made by the first connection mechanism and the connection is made by the second connection mechanism. An apparatus main body, and a cover member attached to the apparatus main body so as to be openable and closable and covering a part of the apparatus main body,
By opening operation of said cover member is made, the first connection release and uncoupling by the second connection mechanism by the coupling mechanism is made, the drive-side coupling member is moved away from the holding side coupling member Move in the direction,
When the cover member is closed, the drive side coupling member does not advance toward the holding body side coupling member, and the cover member is closed and the cover member is closed. Later, after the connection by the first connection mechanism and the connection by the second connection mechanism are performed and the cover member is closed, the drive side coupling member advances toward the holding body side coupling member. The image forming apparatus according to claim 1. A belt arranged in contact with each of the plurality of image carriers;
The belt is disposed apart from the image carrier that is rotationally driven by the first group drive-side coupling member in the first mode, and the second mode in the second mode. The image forming apparatus according to claim 1, wherein the image forming apparatus is disposed apart from the image carrier that is rotationally driven by a driving side coupling member of the group.   The first group of driving side coupling members rotationally drive the image holding members respectively holding yellow, magenta, and cyan toner images, and the second group of driving side coupling members is a black toner image. The image forming apparatus according to claim 1, wherein the image holding member that holds the image is rotated. A plurality of image holders arranged rotatably;
Wherein the plurality of provided corresponding to each of the image carrier of the image carrier Rutotomoni, rotatably provided around a rotation axis along the axial direction of the image carrier, and, the image carrier coaxially A plurality of holding body side coupling members provided on the image holding body and capable of transmitting a driving force to the image holding body;
The holding body side coupling member is provided corresponding to each of the plurality of holding body side coupling members, is provided rotatably about a rotation axis along the axial direction of the holding body side coupling member, and the holding body side coupling member A plurality of drive-side coupling members provided on the same axis , coupled to each of the plurality of holder-side coupling members, and configured to rotate the image holder via the holder-side coupling member;
A connection release mechanism for moving the drive side coupling member back and forth along the axial direction of the drive side coupling member and connecting or releasing the drive side coupling member and the holding body side coupling member;
The connection release mechanism is configured to connect or release a first group of drive side coupling members of the plurality of drive side coupling members to a corresponding holding body side coupling member, and a second that does not belong to the first group. Connection or release of the driving side coupling member of the group and the corresponding holding body side coupling member, and all of the driving side coupling members of the plurality of driving side coupling members and the corresponding holding body side coupling member. An image forming apparatus that selectively performs connection or release. The connection release mechanism is connected to the holding-side coupling member corresponding to the driving-side coupling member by rotating in one direction, and is driven to rotate in the other direction. The image forming apparatus according to claim 9, further comprising a drive member that releases the connection with the corresponding holding member side coupling member. The connection release mechanism includes a first slide member that performs connection or release between the driving side coupling member of the first group and the corresponding holding body side coupling member by sliding, and the second group by sliding. A second slide member for connecting or releasing the drive side coupling member and the corresponding holding body side coupling member.
The image forming apparatus according to claim 9, wherein the first slide member and the second slide member are disposed to overlap each other. The connection release mechanism is connected to the holding body side coupling member corresponding to the first group driving side coupling member by moving forward and backward with respect to the holding body side coupling member in conjunction with the slide of the first slide member. A first advancing / retracting member for releasing, and a holding body side coupling member corresponding to the second driving side coupling member that moves forward and backward with respect to the holding body side coupling member in conjunction with the sliding of the second slide member; A second advancing / retreating member that performs connection or release with
Said first reciprocating member and said second reciprocating member, claim, characterized in that it is disposed on one slide member side of said first slide member and the second slide member 11 The image forming apparatus described. The advancing / retreating member disposed on the one slide member side so as to be interlocked with the slide of the other slide member of the first slide member and the second slide member is connected to the one slide member. The image forming apparatus according to claim 12 , wherein the image forming apparatus is interlocked with the other slide member through the formed through hole.

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