JP2011008131A - Image forming apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To detachably mount a plurality of imaging units with image carriers and a transfer unit with an intermediate transfer belt into an image forming apparatus, so that they are easily and appropriately positioned at a low cost and also they are easily detached.SOLUTION: The image forming apparatus includes the plurality of imaging units 10A to 10D and the transfer unit 20 which are mounted in a body 1 of the apparatus so as to be detachable, the imaging units having the image carriers 11 rotated and driven with toner images thereon, and the transfer unit having the intermediate transfer belt 21 trained about a rotation roller 22 and rotated and driven. The apparatus includes transfer unit positioning portions 31a and 31b for positioning the transfer unit; and an imaging unit positioning section 32 for positioning each imaging unit. A pair of positioning members 30A and 30B of the identical shape are mounted in the body of the apparatus at a required time interval.

Description

  The present invention relates to an image forming apparatus such as a copying machine or a printer, and in particular, a plurality of imaging units having an image carrier that holds and rotates a toner image is detachably mounted in the apparatus body. An image formed by detachably mounting a transfer unit, in which a toner image held on an image carrier in each imaging unit is transferred, to an endless intermediate transfer belt that is driven to rotate around a rotation roller. In the forming apparatus, the plurality of imaging units and the transfer unit can be easily and appropriately positioned at low cost, and the imaging unit and the transfer unit can be easily attached and detached.

  Conventionally, various types of image forming apparatuses such as copying machines and printers have been used.

  In recent years, as an image forming apparatus for forming a full-color image, toner images having different colors are formed on a plurality of image carriers, and the toner images formed on the image carriers are transferred to an intermediate transfer belt. A full-color toner image is formed on the intermediate transfer belt, and the full-color toner image thus formed on the intermediate transfer belt is transferred onto a recording paper or the like.

  Further, in the image forming apparatus as described above, the above-described image carrier and intermediate transfer belt can be easily set in the image forming apparatus, and the operation for replacing them can be easily performed. In addition, the intermediate transfer belt and the image carrier are unitized.

  As disclosed in Patent Document 1, a plurality of imaging units having an image carrier that holds and rotates a toner image is detachably mounted in the apparatus main body, and is rotated around a rotation roller. There has been proposed an image forming apparatus in which a transfer unit in which a toner image held on an image carrier in each imaging unit is transferred to a driven endless intermediate transfer belt is detachably mounted in the apparatus main body. .

  Here, in the image forming apparatus using the transfer unit and the imaging unit as described above, when the transfer unit and the imaging unit are set in the image forming apparatus, the transfer unit and the imaging unit are The image forming apparatus is mounted on each mounting portion provided in the image forming apparatus.

  However, when the transfer unit and the imaging unit are mounted on the respective mounting portions provided in the image forming apparatus as described above, even if a slight shift occurs in each mounting position, the transfer unit The positional relationship between the intermediate transfer belt provided in the image forming unit and the image carrier provided in the imaging unit is deviated, which makes it impossible to form a good image.

  Further, if the mounting portions for mounting the transfer unit and the imaging unit are separately provided in the image forming apparatus as described above, there is a problem that the cost increases and the size of the apparatus increases.

  Conventionally, as shown in Patent Document 2, a positioning block that supports the photosensitive drum on the support frame, a guide hole provided in the positioning block, a transfer roller support member that supports the transfer roller, Using a transfer belt and a contact transfer device provided with a guide pin for determining the position of the transfer roller axis with respect to the photosensitive drum axis by engaging with the guide hole of the positioning block provided on the transfer roller support member, There has also been proposed an image forming apparatus that corrects the uneven transfer by correcting the deviation of the center position between the nip width and the transfer nip width.

  However, even in this image forming apparatus, when a plurality of imaging units having an image carrier are used, a large number of parts are required, and a space for providing these parts is also required. There was a problem of increasing the size.

JP 2001-356546 A JP 11-194629 A

  According to the present invention, a plurality of imaging units having an image carrier that holds and rotates a toner image is detachably mounted in the apparatus main body, and is endlessly driven and rotated around a rotation roller. An object of the present invention is to solve the above-described problems in an image forming apparatus in which a transfer unit in which a toner image held on an image carrier in each imaging unit is transferred to an intermediate transfer belt is detachably mounted in the apparatus main body. To do.

  That is, according to the present invention, in the image forming apparatus as described above, the positioning of the plurality of imaging units and the transfer unit can be performed easily and appropriately at low cost, and the imaging unit and the transfer unit can be easily attached and detached. It is an object to do.

  In the present invention, in order to solve the above-described problems, a plurality of imaging units having an image carrier that holds and rotates a toner image is detachably mounted in the apparatus main body, and is attached to the rotating roller. An image forming apparatus in which a transfer unit in which a toner image held on an image carrier in the imaging unit is transferred to an endless intermediate transfer belt that is laid and rotated is detachably mounted in the apparatus main body. A pair of positioning members having the same shape and provided with a transfer unit positioning unit for positioning the transfer unit and a plurality of imaging unit positioning units for positioning each imaging unit are disposed in the apparatus body with a predetermined interval therebetween. I tried to put it on.

  Here, when the imaging unit and the transfer unit are positioned and detachably mounted in the apparatus main body by the pair of positioning members mounted in the apparatus main body through the required interval as described above, The unit is inserted in a direction intersecting with the pair of positioning members and positioned by the pair of positioning members, and the transfer unit is inserted in a direction along the pair of positioning members and positioned by the pair of positioning members. You can make it.

  Further, the positioning member is made of a long and thin plate material, and the transfer unit positioning portion is a mechanism for rotatably locking the rotation shaft of the rotation roller in the transfer unit on one end side in the longitudinal direction of the positioning member. A stop recess is provided, and an engaging portion that engages with a holding member that rotatably holds the image carrier in the imaging unit is provided in the longitudinal direction of the positioning member at a predetermined interval as the imaging unit positioning portion. A plurality of them can be used.

  Further, in such a positioning member, a plurality of locking recesses for rotatably locking the rotation shaft of the rotation roller in the transfer unit are provided in the vertical direction with a required interval, and the image carrier in the imaging unit can be rotated. The engaging portion that engages with the holding member to be held can be formed in a tapered shape contracted on the lower side of the positioning member.

  Then, when positioning the imaging unit or the transfer unit with this positioning member, the pair of positioning members on the front side with respect to the positioning member on the back side in the direction in which the imaging unit is inserted are shifted upward. The positioning member is mounted in the apparatus main body, and the rotation shaft of the rotation roller in the transfer unit is engaged with the respective locking recesses at the positions where the heights of the positioning member on the back side and the positioning member on the near side coincide with each other. The holding roller is held horizontally and the holding member that holds the image carrier rotatably is formed into a tapered contracted shape provided in each positioning member. Adjusting means for adjusting the position engaged with the joint is provided to hold the image carrier horizontally. It is preferable Unisuru.

  In addition, a locking recess in each positioning portion is provided on the near side in the insertion direction of the transfer unit, and the rotation shaft of the rotating roller in the transfer unit is formed in the locking recess at a position protruding laterally from the transfer unit. It is preferable to be locked in a rotatable manner.

  According to the present invention, the image carrier in the imaging unit described above is provided with a plurality of imaging units having an image carrier that holds and rotates the toner image and an endless intermediate transfer belt that is stretched around a rotary roller. A pair of positioning members provided with a transfer unit positioning portion and a plurality of imaging unit positioning portions in the same shape for detachably mounting the transfer unit to which the toner image held on the body is transferred in the apparatus main body. Are mounted in the apparatus main body through a required interval, and the transfer unit positioning portion of the pair of positioning members positions the transfer unit, and the imaging unit positioning portions position each imaging unit. .

  In this way, the transfer unit and each imaging unit can be appropriately positioned at a predetermined position in the apparatus body and detachably mounted using one type of positioning member having the same shape. Thus, the transfer unit and each imaging unit can be easily and appropriately mounted in the apparatus main body at low cost, and the apparatus is not increased in size.

  Further, in the above positioning member, a plurality of locking recesses for rotatably locking the rotation shaft of the rotating roller in the transfer unit are provided in the vertical direction with a required interval, and the image carrier in the imaging unit is rotatably held. When the engaging portion that engages with the holding member is formed in a tapered contracted shape on the lower side of the positioning member, the position of the positioning member on the front side of the positioning member on the back side in the direction in which the imaging unit is inserted is set. The pair of positioning members are mounted in the apparatus main body while being shifted upward, and the rotation shafts of the rotary rollers in the transfer unit described above have the same height on the positioning member on the back side and the positioning member on the front side. The rotating roller is held horizontally by being locked in the respective locking recesses in the position. In addition, the holding member that rotatably holds the image carrier is adjusted to adjust the position to be engaged with the engaging portion formed in the tapered shape provided in each positioning member. Means can be provided to hold the image carrier horizontally.

  In this way, even when the position of the positioning member on the front side relative to the positioning member on the far side in the direction in which the imaging unit is inserted is shifted upward, the rotation roller in the transfer unit and the image carrier in each imaging unit With the body held horizontally, the transfer unit and each imaging unit are properly positioned. In addition, as described above, the positioning member on the near side is positioned above the positioning member on the far side, so that each imaging unit is inserted or pulled out in a direction intersecting the pair of positioning members. When mounting each imaging unit in the apparatus body or taking it out from the apparatus body, the positioning member on the front side does not get in the way, and it is easy to attach and detach each imaging unit in the apparatus body. Will be able to do.

  In addition, a locking recess in each positioning portion is provided on the near side in the insertion direction of the transfer unit, and the rotation shaft of the rotating roller in the transfer unit is formed in the locking recess at a position protruding laterally from the transfer unit. When it is locked in a rotatable manner, the transfer unit is inserted or pulled out in the direction along the pair of positioning members, and the transfer unit is mounted in the apparatus main body, or the transfer unit is taken out from the apparatus main body. In this case, the transfer unit is prevented from colliding with the pair of positioning members and being damaged, so that the transfer unit can be easily attached to and detached from the apparatus main body.

1 is a schematic explanatory diagram illustrating a state in which image formation is performed by an image forming apparatus according to an embodiment of the present invention. FIG. 2 is a schematic perspective view showing a pair of positioning members having the same shape provided in the apparatus main body in the image forming apparatus of the embodiment. In the image forming apparatus according to the above-described embodiment, when the pair of positioning members is mounted in the apparatus main body, the positions of the pair of positioning members are shifted in the vertical direction and arranged so as to face each other with a required interval. It is the schematic perspective view which showed. In the image forming apparatus of the above embodiment, a schematic perspective view showing a state in which each imaging unit and a transfer unit are positioned and mounted between the pair of positioning members from the front side in the insertion direction of the imaging unit. is there. In the image forming apparatus of the above-described embodiment, a schematic perspective view showing a state in which each imaging unit and a transfer unit are positioned and mounted between the pair of positioning members from the back side in the insertion direction of the imaging unit. is there. FIG. 4 is a schematic plan view showing a state in which the transfer unit is positioned and mounted between the pair of positioning members in the image forming apparatus of the embodiment.

  Hereinafter, an image forming apparatus according to an embodiment of the present invention will be specifically described with reference to the accompanying drawings. The image forming apparatus according to the present invention is not limited to the one shown in the following embodiment, and can be implemented with appropriate modifications within a range not changing the gist thereof.

  In the image forming apparatus of this embodiment, as shown in FIG. 1, four imaging units 10 </ b> A to 10 </ b> D and a transfer unit 20 are detachably mounted in the apparatus main body 1.

  Here, in each of the imaging units 10A to 10D, a drum-shaped photoconductor 11 that rotates about a rotation shaft 11a is provided as an image carrier that holds and rotates a toner image. A charging member 12 comprising a charging roller for charging the surface of the photoconductor 11, and an exposure device 13 for performing exposure according to image information on the surface of the charged photoconductor 11 to form an electrostatic latent image on the surface of the photoconductor 11. A developing device 14 that supplies toner to the electrostatic latent image formed on the surface of the photoconductor 11 to form a toner image, and the toner image formed on the surface of the photoconductor 11 is transferred to the intermediate transfer belt 21. A first cleaning device 15 is provided for removing residues such as toner remaining on the surface of the photoconductor 11 after being transferred to the surface.

  In each of the developing devices 14 in the imaging units 10A to 10D, toners having different colors of black, yellow, magenta, and cyan are accommodated.

  In the transfer unit 20, an endless intermediate transfer belt 21 is provided so as to span a pair of rotating rollers 22 and 23, and the intermediate transfer belt 21 is driven to rotate by one rotating roller 22 rotating. At the same time, four primary transfer rollers 24 are provided on the inner peripheral side of the intermediate transfer belt 21 so as to face the photoreceptors 11 in the imaging units 10A to 10D with the intermediate transfer belt 21 therebetween.

  In the image forming apparatus according to this embodiment, when full-color image formation is performed, the surface of each photoconductor 11 in each of the imaging units 10A to 10D is charged by the charging member 12, respectively. The surface of each charged photoconductor 11 is exposed by the exposure device 13 according to the image information to form an electrostatic latent image on the surface of each photoconductor 11.

  Then, toner of each color is supplied from the corresponding developing device 14 to each photoconductor 11 on which the electrostatic latent image is formed in this manner, and the surface of each photoconductor 11 in each imaging unit 10A to 10D. A toner image of each color is formed on the screen.

  Next, the toner images of the respective colors formed on the surfaces of the respective photoreceptors 11 in the respective imaging units 10A to 10D in this way are spread over the rotation rollers 22 and 23 on the surface of the intermediate transfer belt 21 that is rotationally moved. Then, the toner images are sequentially transferred by the primary transfer rollers 24 provided on the inner peripheral side of the intermediate transfer belt 21 so as to face the photoconductors 11, and a full-color toner image is formed on the surface of the intermediate transfer belt 21. Try to form.

  Then, after the full-color toner image is transferred to the intermediate transfer belt 21 in this way, residues such as toner remaining on the surface of each photoconductor 11 are removed from the surface of each photoconductor 11 by the first cleaning device 16, respectively. Like to do.

  On the other hand, the full-color toner image formed on the surface of the intermediate transfer belt 21 as described above is guided to the transfer portion where the one rotary roller 22 and the secondary transfer roller 2 face each other, and the recording medium S is supplied. The recording medium S is fed by the paper roller 3, and the recording medium S is guided by the timing roller 4 to a transfer portion where the rotation roller 22 and the transfer roller 2 face each other at an appropriate timing, and a full-color toner image on the surface of the intermediate transfer belt 21. Is transferred to the recording medium S.

  Next, the recording medium S on which the full-color toner image is transferred in this way is guided to a fixing unit provided with a pair of fixing rollers 6 and 6, and the above-described full-color toner image is interposed between the pair of fixing rollers 6 and 6. Is fixed to the recording medium S, and then the recording medium S is discharged by the discharge roller 7.

  Further, after the full-color toner image formed on the surface of the intermediate transfer belt 21 as described above is transferred to the recording medium S, the residue such as toner remaining on the surface of the intermediate transfer belt 21 is removed by the second cleaning device. 8 is removed from the intermediate transfer belt 21.

  Here, in the image forming apparatus of this embodiment, when the imaging units 10A to 10D are detachably mounted in the apparatus main body 1, a front door (not shown) provided on the front side of the apparatus main body 1 is used. And the imaging units 10A to 10D are inserted into the apparatus main body 1 from the front side of the apparatus main body 1 in a direction crossing the moving direction of the intermediate transfer belt 21. Each of the imaging units 10A to 10D inserted into the apparatus main body 1 is pulled out from the apparatus main body 1.

  In order to detachably mount the transfer unit 20 in the apparatus main body 1, as shown in FIG. 1, a side door 9 holding the secondary transfer roller 2 is provided on the side surface of the apparatus main body 1, The side door 9 is opened, and the transfer unit 20 is inserted into the apparatus main body 1 along the moving direction of the intermediate transfer belt 21 from the secondary transfer roller 2 side, and the transfer inserted into the apparatus main body 1 in this way. The unit 20 is pulled out from the inside of the apparatus main body 1.

  When the imaging units 10A to 10D and the transfer unit 20 are positioned and set at predetermined positions in the apparatus main body 1, the image forming apparatus according to this embodiment has an elongated shape as shown in FIG. A pair of positioning members 30A and 30B made of a plate material and having the same shape are used.

  Here, in the pair of positioning members 30A and 30B, as a transfer unit positioning portion for positioning the transfer unit 20, the rotation of the rotating roller 22 in the transfer unit 20 is arranged on one end side in the longitudinal direction of each positioning member 30A and 30B. Two locking recesses 31a and 31b for locking the shaft 22a in a rotatable manner are provided in the vertical direction with a required interval therebetween, and the rotating shaft 11a of the photoreceptor 11 in each of the imaging units 10A to 10D serves as an imaging unit positioning portion. Four engaging portions 32 that engage with holding members 16a and 16b on both sides that rotatably hold both end portions of the positioning members 30A and 30B are provided on the lower side of the positioning members 30A and 30B in the longitudinal direction with a required interval. Each of the engaging portions 32 is contracted in a tapered shape upward. It is formed in a mountain shape.

  Here, as shown in FIG. 3, when the imaging units 10A to 10D and the transfer unit 20 are positioned and set at predetermined positions in the apparatus body 1 by the pair of positioning members 30A and 30B, as shown in FIG. The position of the positioning member 30A on the front side with respect to the positioning member 30B on the back side in the direction in which the imaging units 10A to 10D are inserted is shifted upward, and the lower locking recess 31b provided on the positioning member 30A on the front side. And a pair of positioning members 30A and 30B in the direction in which the imaging units 10A to 10D are inserted so that the upper locking recess 31a provided in the positioning member 30B on the back side is at the same height. It is made to mount in the predetermined position in the apparatus main body 1 so that it may oppose through a required space | interval.

  Further, with respect to the pair of positioning members 30 </ b> A and 30 </ b> B mounted in the apparatus main body 1, the imaging units 10 </ b> A to 10 </ b> D are connected to the moving direction of the intermediate transfer belt 21 from the front side of the apparatus main body 1. In order to insert and position in the apparatus main body 1 in the intersecting direction, as shown in FIGS. 4 and 5, holding members 16a for rotatably holding both ends of the rotating shaft 11a of the respective photoreceptors 11, In 16b, a bearing member 16b that rotatably holds the rotating shaft 11a of the photoconductor 11 is used as the holding member 16b on the back side in the insertion direction in which the imaging units 10A to 10D are inserted, while the imaging unit 10A to 10D is inserted. As the holding member 16a on the front side in the direction, the rotating shaft 11a of the photoconductor 11 is rotatably held. So that provision of the over scan Backed bearing member 16a.

  And the bearing member 16b provided in the rotating shaft 11a of the photoreceptor 11 on the back side in the insertion direction in which the imaging units 10A to 10D are inserted is provided on the positioning member 30B located on the back side in the insertion direction of the imaging units 10A to 10D. The bearing member 16a with a ground plate provided on the rotating shaft 11a of the photoconductor 11 on the front side in the insertion direction in which the imaging units 10A to 10D are inserted is engaged with the engaging portion 32 and the insertion direction of the imaging units 10A to 10D. The respective photoconductors 11 in the respective imaging units 10A to 10D are positioned in a state of being held horizontally by being engaged with an engaging portion 32 provided on the positioning member 30A located on the front side.

  When the imaging units 10A to 10D are guided and positioned between the pair of positioning members 30A and 30B in this way, the positioning member 30A on the front side in the insertion direction in which the imaging units 10A to 10D are inserted is displaced upward. Since the imaging units 10A to 10D are inserted in a direction intersecting the pair of positioning members 30A and 30B, the imaging units 10A to 10D are mounted in the apparatus main body 1, When the imaging units 10A to 10D are pulled out in a direction intersecting the pair of positioning members 30A and 30B and the imaging units 10A to 10D are taken out from the apparatus main body 1, the positioning member 30A on the near side is obstructive. Each image is never Work for attaching and detaching the ring unit 10A~10D in the apparatus main body 1 can be easily performed.

  Further, with respect to the pair of positioning members 30A and 30B mounted in the apparatus main body 1 as described above, the transfer unit 20 is moved along the moving direction of the intermediate transfer belt 21 from the secondary transfer roller 2 side. 4 to 6, the transfer unit 20 is held by holding a grip portion 25 provided on the rotating roller 22 side facing the secondary transfer roller 2 as shown in FIGS. 4 to 6. Is inserted into the apparatus main body 1 along the pair of positioning members 30A and 30B by a guide member (not shown) from the rotation roller 23 side opposite to the rotation roller 22 described above.

  Then, the rotating shaft 22a of the rotating roller 22 facing the secondary transfer roller 2 is protruded to the side from the transfer unit 20, and one end side of the protruding rotating shaft 22a is connected to the imaging units 10A to 10D. The other end side of the rotating shaft 22a of the rotating roller 22 is placed in front of the imaging units 10A to 10D in the insertion direction, while being engaged with the upper locking recess 31a provided on the positioning member 30B located on the rear side in the insertion direction. The transfer unit 20 is engaged with a lower locking recess 31b provided on the positioning member 30A positioned on the side, and the rotation roller 22 is held horizontally between the pair of positioning members 30A and 30B. It is positioned so as to be held horizontally.

  In this way, when the end portions on both sides of the rotating shaft 22a protruding to the side from the transfer unit 20 are engaged with the positioning members 30A and 30B for positioning, the end portions on both sides of the rotating shaft 22a are positioned. Is merely in contact with the positioning members 30A and 30B, the transfer unit 20 is inserted into the apparatus main body 1 along the moving direction of the intermediate transfer belt 21 from the secondary transfer roller 2 side, or is taken out from the apparatus main body 1. The other parts of the transfer unit 20 do not come into contact with the positioning members 30A and 30B, and the operation of attaching and detaching the transfer unit 20 to and from the apparatus main body 1 can be easily performed.

  Moreover, in this embodiment, each imaging unit is also in a state where the position of the positioning member 30A on the front side of the positioning member 30B on the back side in the direction in which the imaging units 10A to 10D are inserted as described above is shifted upward. Each of the photoconductors 10A to 10D is positioned while being held horizontally, and the rotation roller 22 of the transfer unit 20 is held horizontally between the pair of positioning members 30A and 30B, so that the transfer unit 20 is horizontally set. Positioning is performed while being held. For this reason, the toner images of the respective colors formed on the surface of each photoconductor 11 as described above are appropriately and sequentially applied to the surface of the intermediate transfer belt 21 that is laid over the rotation rollers 22 and 23 and rotated. As a result, the image is transferred and the occurrence of uneven transfer is suppressed, and a good full-color image can be obtained.

DESCRIPTION OF SYMBOLS 1 Device main body 2 Secondary transfer roller 3 Paper feed roller 4 Timing roller 6 Fixing device 7 Paper discharge roller 8 Second cleaning device 9 Side door 10A to 10D Imaging unit 11 Photoconductor (image carrier)
11a Rotating shaft 12 Charging member 13 Exposure device 14 Developing device 15 First cleaning device 16a Bearing member with earth plate (holding member)
16b Bearing member (holding member)
DESCRIPTION OF SYMBOLS 20 Transfer unit 21 Intermediate transfer belt 22 Rotating roller 22a Rotating shaft 23 Rotating roller 24 Primary transfer roller 25 Holding part 30A, 30B Positioning member 31a, 31b Locking recessed part (Transfer unit positioning part)
32 Engagement part (Imaging unit positioning part)
S Recording medium

Claims (6)

  A plurality of imaging units each having an image carrier that holds and rotates a toner image is detachably mounted in the apparatus main body, and is attached to an endless intermediate transfer belt that is rotated around a rotation roller. In an image forming apparatus in which a transfer unit to which a toner image held on an image carrier in each imaging unit is transferred is detachably mounted in the apparatus main body, a transfer unit positioning unit for positioning the transfer unit and each imaging An image forming apparatus comprising: a pair of positioning members having a plurality of imaging unit positioning portions for positioning a unit and having the same shape, mounted in the apparatus main body at a predetermined interval.   The image forming apparatus according to claim 1, wherein the imaging unit is inserted in a direction intersecting with a pair of positioning members mounted in the apparatus body via a required interval, and positioned by the pair of positioning members. An image forming apparatus.   3. The image forming apparatus according to claim 1, wherein the transfer unit is inserted in a direction along a pair of positioning members that are mounted in the apparatus main body via a required interval, and the pair of positioning members. An image forming apparatus characterized by being positioned by the above.   4. The image forming apparatus according to claim 1, wherein the positioning member is formed of an elongated plate material, and the transfer unit positioning portion is provided on one end side in the longitudinal direction of the positioning member. A locking recess for rotatably locking the rotation shaft of the rotating roller in the transfer unit is provided, and a holding member for rotatably holding the image carrier in the imaging unit as the imaging unit positioning unit An image forming apparatus, wherein a plurality of engaging portions to be engaged are provided in the longitudinal direction of the positioning member with a required interval therebetween.   5. The image forming apparatus according to claim 4, wherein the positioning member is provided with a plurality of locking recesses for rotating the rotation shaft of the rotation roller in the transfer unit in a vertical direction with a predetermined interval therebetween, and imaging. The engaging portion that engages with the holding member that rotatably holds the image carrier in the unit is formed in a tapered shape on the lower side of the positioning member, and positioning on the back side in the direction in which the imaging unit is inserted The pair of positioning members are mounted in the apparatus main body in a state where the position of the positioning member on the front side of the members is shifted upward, and the rotation shaft of the rotating roller in the transfer unit is positioned on the back side. And the positioning member on the front side are locked in the respective locking recesses at the same height. Thus, the rotary roller is held horizontally, and the holding member for rotatably holding the image carrier is formed in a tapered contracted shape provided on each positioning member. An image forming apparatus, wherein the image carrier is held horizontally by being engaged with a joint portion.   6. The image forming apparatus according to claim 4 or 5, wherein a locking recess in each positioning member is provided on the near side in the insertion direction of the transfer unit, and the rotation shaft of the rotation roller in the transfer unit is the transfer unit. An image forming apparatus, wherein the image forming apparatus is rotatably locked to the locking recess at a position protruding more laterally.

Images