JP2007199660A - Image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an image forming apparatus capable of reducing image defects. <P>SOLUTION: The image forming apparatus 10 has an image formation unit 48 and a belt unit 84 which are attached to and detached from an image forming apparatus main body 12. A photoreceptor 52 is mounted on the image formation unit 48 and an intermediate transfer belt 14 is mounted on the belt unit 84. The belt unit 84 is positioned with respect to the image forming apparatus main body 12 by inserting a positioning pin 126 provided in a driving frame 104 into a through-hole 88a provided in the belt unit 84. The image formation unit 48 is positioned with respect to the belt unit 84 by being pressed against side plates 88 and 89 of the belt unit 84 by an elastic body 144. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

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

A technique related to an image forming apparatus, which includes first and second process means including, for example, a photoconductor, an intermediate transfer belt, a transfer roll, and the like, and aligns the first process means and the second process means. A technique for forming an image shape is known (for example, Patent Document 1).

JP2003-167411A

  However, in the conventional technique, the first process means and the second process means are adopted in separate units, and each unit is positioned with respect to the image forming apparatus main body. For this reason, there has been a problem that positioning errors are accumulated, and the first and second process means are not well aligned and an image defect may occur.

  An object of the present invention is to provide an image forming apparatus that reduces the occurrence of image defects.

  A feature of the present invention is that an image forming apparatus main body, a first unit provided with a first process means, and a second process means aligned with the first process means are provided. Second unit, a first positioning unit that positions the first unit with respect to the image forming apparatus main body, and a second positioning unit that positions the second unit with respect to the first unit. And an image forming apparatus.

  Preferably, the first unit and the second unit are detachable from the image forming apparatus main body.

  Preferably, a drive frame provided in the image forming apparatus main body and mounted with at least a part of a drive system that transmits drive to at least one of the first process means or the second process means. The first positioning means is configured through the drive frame.

  Preferably, the first unit has pressing means for pressing the second unit.

  Preferably, the apparatus further includes a separating unit that separates the first process unit and the second process unit.

  Preferably, the apparatus further comprises third process means aligned with the first process means, and third positioning means for positioning the third process means with respect to the first process means.

  Preferably, the first process means is a belt, and the second process means is an image carrier.

  Preferably, a plurality of the second units are provided.

  The belt may be an intermediate transfer belt or a conveyance belt that conveys a sheet.

  The second feature of the present invention is that the first process means used for at least one of image formation and sheet conveyance is aligned with the first process means, and the image formation or sheet conveyance is performed. An image forming apparatus comprising: a second process unit used for at least one of the first and second process units; and a positioning member in which the first and second process units are in contact with each other to position the first and second process units. It is in.

  Preferably, the first and second process means are in contact with the positioning member at at least two places.

  Preferably, the apparatus further includes first pressing means for pressing the first process means against the positioning member, and second pressing means for pressing the second process means against the positioning member.

  Preferably, the positioning member supports at least one of the first or second process means.

  Preferably, the third process means is aligned with the first and second process means and used for at least one of image formation and sheet conveyance, and a support for supporting the third process means. The positioning member is movably mounted on the support member.

  According to the present invention, it is possible to provide an image forming apparatus capable of reducing the occurrence of image defects.

Next, embodiments of the present invention will be described with reference to the drawings.
1 to 5 show an image forming apparatus 10 according to a first embodiment of the present invention. As shown in FIG. 1, the image forming apparatus 10 includes an image forming apparatus main body 12, and an intermediate transfer belt 14 used as first process means is disposed in the image forming apparatus main body 12. For example, four image forming units 16 are arranged in parallel to the intermediate transfer belt 14, and the image forming apparatus 10 is a so-called tandem system. The image forming unit 16 forms toner images of respective colors of yellow, magenta, cyan, and black on the intermediate transfer belt 14. In the image forming apparatus main body 12, a separation mechanism 15 used as a separation unit for separating the intermediate transfer belt 14 and the photosensitive member 52 used as the second process unit is disposed. As shown in FIG. 3, the image forming apparatus main body 12 is provided with a drive system 17 that transmits driving to the intermediate transfer belt 14 and the image forming means 16.

  A sheet supply device 18 is provided below the image forming apparatus main body 12. The sheet supply device 18 includes a sheet supply cassette 20 on which sheets are stacked, a pickup roll 22 that picks up the sheets stacked on the sheet supply cassette 20, and a feed roll 24 and a retard roll 26 that send out the sheets while rolling them. . The sheet supply cassette 20 is detachably attached to the image forming apparatus main body 12 so that the sheet supply cassette 20 can be pulled out in the front direction in the figure. Sheets such as plain paper and OHP sheets are stacked and stored. ing.

  Near one end of the image forming apparatus main body 12 (near the left end in the figure), a sheet supply path 28 is provided along a substantially vertical direction. The sheet supply path 28 is provided with a transport roll 29, a resist roll 30, a secondary transfer roll 32 used as third process means, a fixing device 34, and a discharge roll 36. The registration roll 30 temporarily stops the sheet sent to the sheet supply path 28 and sends it to the secondary transfer roll 32 at a timing. The fixing device 34 includes a heating roll 34a and a pressure roll 34b, and fixes the toner image on the sheet by applying heat and pressure to the sheet passing between the heating roll 34a and the pressure roll 34b. ing.

  The secondary transfer roll 32 is positioned with respect to the intermediate transfer belt 14 so as to be in contact with or close to the intermediate transfer belt 14, and transfers the toner image formed on the intermediate transfer belt 14 onto a sheet.

  A discharge tray section 38 is provided on the upper part of the image forming apparatus main body 12. The sheet on which the toner image is fixed is discharged onto the discharge tray portion 38 by the discharge roll 36 described above, and is stacked on the discharge tray portion 38. Accordingly, the sheets in the sheet supply cassette 20 are sequentially discharged to the discharge tray unit 38 through a C-shaped path.

  The image forming unit 16 includes an image forming unit 48 provided on one surface of the intermediate transfer belt 14 and used as a second unit, and a primary transfer roll 50 provided on the back surface of the intermediate transfer belt 14. . The image forming unit 48 can be attached to and detached from the image forming apparatus main body 12, and once moved downward, it can be pulled out in the front direction in FIG.

  The image forming unit 48 is aligned with the intermediate transfer belt 14 so as to be in contact with or close to the intermediate transfer belt 14, and the photosensitive member 52 used as the second process means and the photosensitive member 52 are charged. For example, a charging device 54 composed of a roll, an LED (light emitting diode), for example, and an exposure device 56 that forms a latent image on the photosensitive member 52, and a photosensitive device formed by the exposure device 56. A developing device 58 that develops the latent image on the body 52 with toner, and a cleaning device 60 that cleans the toner remaining on the photoconductor 52 after transfer.

The photoconductor 52 includes a photoconductor main body and two bearings 53 mounted on both ends in the longitudinal direction of the photoconductor main body, and the photoconductor main body is rotatably supported by the bearings 53.

  The developing device 58 is, for example, a two-component system, which uses a developer composed of toner and carrier, and has a developing roll 74. On the developing roll 74, a magnetic brush is formed by a carrier. The toner attached to the carrier is conveyed by the magnetic brush, and the latent image on the photoconductor 52 is developed by the toner.

  The cleaning device 60 includes a toner scraping unit 76 formed of, for example, a blade, and the toner scraping unit 76 scrapes off the toner from the surface of the photosensitive member 52.

  The intermediate transfer belt 14 is supported by a plurality of conveying rolls 42, and the belt surface on which the image forming unit 16 described above is provided is horizontal. One of the transport rolls 42 constitutes a backup roll for the secondary transfer roll 32.

  The intermediate transfer belt 14, the plurality of transport rolls 42, and the primary transfer roll 50 are integrated as a belt unit 84 used as a first unit. The belt unit 84 has a belt unit housing 86, the transport roll 42 and the primary transfer roll 50 are rotatably mounted on the belt unit housing 86, and the intermediate transfer belt 14 is stretched around the transport roll 42. . The belt unit 84 can be attached to and detached from the image forming apparatus main body 12, and can be pulled out in the front direction in FIG.

  The belt unit housing 86 has a back side plate 88 on the back side in FIGS. 1 and 2 and a front side plate 89 on the front side in the drawing, and these side plates are connected by a top plate. The belt unit housing 86 is formed with an open portion facing downward, and the intermediate transfer belt 14 is exposed from the open portion. Four notches 49 are formed in the rear side plate 88 and the front side plate 89 in order to arrange the image forming unit 48. The notch 49 has a substantially horizontal edge 49a and a substantially vertical edge 49b.

  At least two through holes 88 a are formed in the back side plate 88. The through hole 88 a is formed perpendicular to the surface of the back side plate 88.

The separation mechanism 15 includes a support plate 140 that supports each image forming unit 48 and a cam 142 that is used as a lowering unit that lowers the support plate 140 and the image forming unit 48. The support plate 140 is made of, for example, a spring, and one end of an elastic body 144 used as pressing means is fixed. The other end of the elastic body 144 is in contact with the bottom surface of the image forming unit 48.
The cam 142 is connected to a handle (not shown). When the operator operates the handle, the support plate 140 is lowered, and as the support plate 140 is lowered, the image forming unit 48 is lowered. The intermediate transfer belt 14 and the photosensitive member 52 are separated from each other. In this embodiment, the separation mechanism 15 separates the intermediate transfer belt 14 and the photosensitive member 52 by moving the photosensitive member 52, but the separation mechanism 15 is at least of the photosensitive member 52 or the intermediate transfer belt 14. Any one may be used as long as the intermediate transfer belt 14 and the photosensitive member 52 are separated from each other.

  By operating the handle connected to the cam 142 from the state where the intermediate transfer belt 14 and the photosensitive member 52 are separated by the separation mechanism 15, the intermediate transfer belt 14 and the photosensitive member 52 are brought into contact with each other again. be able to.

  3 and 4 show the drive system 17. The drive system 17 includes a drive source 102 provided on the image forming apparatus main body 12 side, a photoconductor gear 116 provided on the image forming unit 48 side, and a belt gear 120 provided on the belt unit 84 side.

  The drive source 102 includes a drive gear 106 provided on a drive frame 104 that forms a part of the image forming apparatus main body 12, and a motor 108 that transmits drive to the drive gear 106. The drive gear 106 is attached to the drive frame 104 via a bearing 110, and rotates by receiving a drive from the motor 108. The motor 108 may be attached to the drive frame 104 or may be attached to a place other than the drive frame 104 in the image forming apparatus main body 12.

  The photoconductor gear 116 is attached to an end portion of each photoconductor 52 in the longitudinal direction, and rotates by receiving the drive from the drive gear 106 to rotate the photoconductor 52. The belt gear 120 is attached to an end portion in the longitudinal direction of the transport roll 42 provided at a position facing the secondary transfer roll 32, and rotates by receiving driving from the drive gear 106 to rotate the transport roll 42. Then, when the transport roll 42 rotates, the intermediate transfer belt 14 stretched around the transport roll 42 rotates.

  In the above configuration, the intermediate transfer belt 14 and the photoconductor 52 rotate in opposite directions in synchronization with each other, the surface of the photoconductor 52 is charged by the charging device 54, and a latent image is formed by the exposure device 56. The latent image on the photoreceptor 52 formed by the exposure device 56 is developed by the developing device 58. The toner image developed by the developing device 58 is transferred to the intermediate transfer belt 14 by the primary transfer roll 50. The toner images of the respective colors formed by the image forming units 16 are superimposed as the intermediate transfer belt 14 moves.

  On the other hand, the sheets stacked on the sheet supply cassette 20 of the sheet supply apparatus 18 are fed one by one to the sheet supply path 28 by the pickup roll 22, the feed roll 24, the retard roll 26, and the like. The sheet fed to the sheet supply path 28 comes into contact with the registration roll 30, temporarily stops, and is fed to the secondary transfer roll 32 at a timing. The toner image on the intermediate transfer belt 14 is transferred to the sheet by the secondary transfer roll 32. The sheet on which the toner image has been transferred is further sent to the fixing device 34, where the toner image is fixed to the sheet by heat and pressure. The sheet on which the toner image is fixed by the fixing device 34 is discharged to the discharge tray portion 38 by the discharge roll 36.

  In such an image forming apparatus 10, the belt unit 84 and the image forming unit 48 are attached to the image forming apparatus main body 12. The photosensitive member 52 attached to the image forming unit 48 and the intermediate transfer belt 14 attached to the belt unit 84 are used while being aligned with each other to form an image. For this reason, if the image forming unit 48 and the belt unit 84 are not accurately positioned, an error from the design value occurs in the positional relationship between the photosensitive member 52 and the intermediate transfer belt 14, and an image such as color misregistration is formed in the formed image. Defects will occur. In this embodiment, by devising the positioning of the belt unit 84 and the image forming unit 48, the intermediate transfer belt 14 and the photosensitive member 52 are accurately aligned, and image defects are less likely to occur. It is configured as follows.

  As shown in FIGS. 1 and 5, the belt unit 84 is positioned with respect to the drive frame 104. Positioning pins 126 and 126 are attached to the drive frame 104 at positions corresponding to the through holes 88a and 88a formed in the back side plate 88 of the belt unit housing 86, respectively. The belt unit 84 is attached to the image forming apparatus main body 12 so that the positioning pins 126 and 126 are inserted into the through holes 88a and 88a, thereby positioning the belt unit 84 with respect to the image forming apparatus main body 12. Is made. As described above, the positioning pins 126 and 126 and the through holes 88a and 88a are used as first positioning means for positioning the belt unit 84 with respect to the image forming apparatus main body 12.

  The image forming unit 48 is positioned with respect to the belt unit 84 as shown in FIGS. In a state where the image forming unit 48 is mounted at a position used for image formation, the image forming unit 48 is respectively applied to the back side plate 88 and the front side plate 89 of the belt unit 84 by the elastic body 144 used as pressing means. The formed notch 49 is urged and pressed in the direction of the edges 49a and 49b. When the image forming unit 48 is biased, the bearing 53 partially exposed from the image forming unit 48 is pressed against the edge 49a and the edge 49b, and the 48 belt units of the image forming unit 48 are pressed. Positioning relative to 84 is made. Thus, the edge portion 49a, the edge portion 49b, and the bearing 53 are used as second positioning means for positioning the image forming unit 48 with respect to the belt unit 84.

  As described above, in the image forming apparatus 10 according to this embodiment, the belt unit 84 is positioned with respect to the image forming apparatus main body 12, and the image forming unit 48 is positioned with respect to the belt unit 84. Since the image forming unit 48 is directly positioned with respect to the belt unit 84 in this way, there is an error in the positional relationship between the intermediate transfer belt 14 attached to the belt unit 84 and the photosensitive member 52 attached to the image forming unit 48. The intermediate transfer belt 14 and the photosensitive member 52 are accurately aligned. On the other hand, in the method of positioning both the belt unit 84 and the image forming unit 48 with respect to the image forming apparatus main body 12, the positional deviation of the belt unit 84 relative to the image forming apparatus main body 12 and the image of the image forming unit 48. When the positional deviation with respect to the forming apparatus main body 12 accumulates, the positional alignment between the intermediate transfer belt 14 and the photoconductor 52 is likely to occur, and there is a possibility that an image defect due to this will occur.

  A notch 85 for positioning the secondary transfer roll 32 with respect to the intermediate transfer belt 14 is formed in the front side plate 89 and the back side plate 88 of the belt unit 84. The bearing 35 attached to the end of the secondary transfer roll 32 is pressed into the notch 85 by an elastic body 37 made of, for example, a spring, so that the secondary transfer roll 32 is positioned with respect to the intermediate transfer belt 14. The Thus, the notch 85 and the bearing 35 are used as third positioning means for positioning the secondary transfer roll 32 with respect to the intermediate transfer belt 14.

  In the image forming apparatus 10 configured as described above, in order to pull out the image forming unit 48 from the image forming apparatus main body 12, the operator operates the handle connected to the cam 142 to operate the support plate 140 and the image forming unit. 48 is lowered to separate the intermediate transfer belt 14 and the photosensitive member 52 from each other. Then, after the intermediate transfer belt 14 and the photosensitive member 52 are separated from each other, the image forming unit 48 is pulled out from the image forming apparatus main body 12.

  On the other hand, in order to mount the image forming unit 48 in the image forming apparatus main body 12, after the image forming unit 48 is inserted into the image forming apparatus main body 12, the operator operates the handle connected to the cam 142, The support plate 140 and the image forming unit 48 are raised, and the intermediate transfer belt 14 and the photosensitive member 52 are brought into contact with each other.

  When pulling out the belt unit 84 from the image forming apparatus main body 12, as in the case of pulling out the image forming unit 48, after the intermediate transfer belt 14 and the photosensitive member 52 are separated from each other, the belt unit 84 is removed from the image forming apparatus main body 12. Pull out from. Also, when the belt unit 84 is attached to the image forming apparatus main body 12, the intermediate transfer belt 14 and the photosensitive member 52 are brought into contact with each other after the belt unit 84 is attached to the image forming apparatus main body 12.

  FIG. 6 shows a belt unit housing 86 used in the image forming apparatus 10 according to the second embodiment of the present invention. In the first embodiment described above, the notch 49 formed in the belt unit housing 86 has a substantially horizontal edge portion 49a and a substantially vertical edge portion 49b. On the other hand, in the second embodiment, the notch 49 has an edge portion 49a formed obliquely so as to incline in the direction opposite to the traveling direction of the intermediate transfer belt 14 with respect to the vertical direction, and the vertical direction. And an edge portion 49b formed obliquely so as to be inclined in the traveling direction of the intermediate transfer belt 14. In FIG. 6, only the cutout 49 formed on the leftmost side of the belt unit housing 86 is shown, but in the second embodiment as well, four side plates are provided on each side plate as in the first embodiment. A notch is formed. FIG. 6 shows only the front side plate 89, but the back side plate 88 has the same shape as the front side plate 89, and the back side plate 88 also has four notches 49 formed therein. Yes.

  FIG. 7 shows a state in which the photoconductor 52 and the primary transfer roll 50 are aligned in the image forming apparatus 10 according to the second embodiment of the present invention. In the first embodiment, the bearing 53 is urged toward the belt unit housing 86 by the elastic body 144 and pressed against the belt unit housing 86, whereby the photosensitive member 52 is positioned with respect to the belt unit housing 86. It was. Also in the second embodiment, as in the first embodiment, the photosensitive member 52 is pressed toward the belt unit housing 86 used as the positioning member by the elastic body 144 used as the first pressing means. It is positioned with respect to the belt unit housing 86. In this second embodiment, in addition to the photosensitive member 52, the primary transfer roll 50 used as the second process means is also pressed against the belt unit housing 86 and positioned with respect to the belt unit housing 86. . The photoreceptor 52 and the primary transfer roll 50 are aligned by being pressed against the belt unit housing 86 that is the same member.

  The primary transfer roll 50 includes a roll main body 150, a shaft 152 provided so as to penetrate the roll main body 150, and two bearings 154 attached to both ends of the shaft 152. In FIG. 7, only the bearing 154 disposed on the front side of the two bearings 154 is shown. The bearing 154 has a smaller diameter than the roll main body 150, and supports the roll main body 150 in a rotatable manner.

  One end side of a spring 156 made of an elastic body is connected to the bearing 154 as a second pressing means. The other end side of the spring 156 is formed on the side surface of the belt unit housing 86 and is connected to a connecting portion 158 made of, for example, a protrusion. In a state where the other end side is connected to the connecting portion 158 and one end side is connected to the bearing 154, the spring 156 is in an extended state. Therefore, the bearing 154 is pressed against the edge portion 49a and the edge portion 49b of the belt unit housing 86. The primary transfer roll 50 is positioned with respect to the belt unit housing 86 by pressing the bearing 154 against the belt unit housing 86.

  As described above, in the second embodiment, the photosensitive member 52 and the primary transfer roll 50 are both positioned with respect to the belt unit housing 86 that is the same member. For this reason, compared with the case where the photosensitive member 52 and the primary transfer roll 50 are respectively positioned with respect to two separate members, the accumulation of errors is less likely to occur, and the photosensitive member 52 and the primary transfer roll 50 Are better aligned.

  In the second embodiment, the primary transfer roll 50 and the photoconductor 52 are in contact with the belt unit housing 86 at two locations, the edge portion 49a and the edge portion 49b. For this reason, compared with the case where it contacts the belt unit housing 86 only at one place, it is positioned better with respect to the belt unit housing 86.

  In the second embodiment, the belt unit housing 86 is not only used as a positioning member for positioning the primary transfer roll 50 and the photosensitive member 52 but also as a support member for supporting the primary transfer roll 50. Are also used. For this reason, compared with the case where the supporting member which supports the primary transfer roll 50 is provided separately from the positioning member which is the target for positioning the primary transfer roll 50 and the photoreceptor 52, the apparatus configuration can be simplified. it can.

  FIG. 7 shows a state in which the leftmost photosensitive member 52 and the primary transfer roll 50 are positioned with respect to the belt unit housing 86, but the other three photosensitive members 52 and the primary transfer roller 50 are positioned. The roll 50 is also positioned with respect to the belt unit housing 86 in the same manner as illustrated. In the description of the second embodiment, the description of the same parts as those of the first embodiment is omitted. 6 and 7 are assigned the same numbers as in the first embodiment.

  FIG. 8 shows a belt unit housing 86 used in the image forming apparatus 10 according to the third embodiment of the present invention. In the first and second embodiments described above, the notch 49 formed in the belt unit housing 86 has edge portions 49a and 49b each having a substantially linear shape. On the other hand, in the third embodiment, the notch 49 has an edge portion 49c having an arc shape having substantially the same diameter as the outer diameter of the bearing 53, and an arc shape having substantially the same diameter as the outer diameter of the bearing 154. And an edge portion 49d. Also in the third embodiment, as in the first and second embodiments, the front side plate 89 and the back side plate 88 are each formed with four notches 49.

  FIG. 9 shows a state in which the photoreceptor 52 and the primary transfer roll 50 are aligned in the image forming apparatus 10 according to the third embodiment of the present invention. In the second embodiment, the primary transfer roll 50 and the photoreceptor 52 are both pressed by the edge portion 49a and the edge portion 49b having a linear shape. On the other hand, in the third embodiment, the primary transfer roll 50 is pressed against the edge 49d having an arc shape, and the photoconductor 52 is pressed to the edge 49c having an arc shape. In the third embodiment, when the machining accuracy is extremely high and there is no shape error of the part, the edge portion 49d and the bearing 154 of the primary transfer roll 50 are in contact with each other even if the machining accuracy is general. The edge portion 49d and the bearing 154 of the primary transfer roll 50 are in contact at least at two points. Further, the edge portion 49c and the bearing 53 of the photosensitive member 52 are also in contact with each other at at least two points.

  FIG. 9 shows a state where the leftmost photosensitive member 52 and primary transfer roll 50 are positioned with respect to the belt unit housing 86, but the other three photosensitive members 52 and primary transfer are shown. The roll 50 is also positioned with respect to the belt unit housing 86 in the same manner as illustrated. In the description of the third embodiment, the description of the same parts as those of the first embodiment is omitted. 8 and 9 are assigned the same numbers as those in the first embodiment.

  In the second and third embodiments described above, the photosensitive member 52 and the primary transfer roll 50 are positioned on the belt unit casing 86 using the belt unit casing 86 as a positioning member. By using the frame of the apparatus main body 12 or the casing of the image forming unit 48 as a positioning member, the photosensitive member 52 and the primary transfer roll 50 may be positioned on the frame of the image forming apparatus main body 12 or the casing of the image forming unit 48. good.

  FIG. 10 shows a belt unit 84 used in the fourth embodiment of the present invention. In the second and third embodiments, the primary transfer roll 50 is pressed against the belt unit housing 86 and positioned with respect to the belt unit housing 86. In contrast, in the fourth embodiment, the primary transfer roll 50 is supported by the belt unit housing 86 using the spring 156 but is not positioned with respect to the belt unit housing 86. That is, by adjusting the shape of the notch 49 and the strength of the spring 156, the bearing 154 does not contact the edge of the notch 49.

  In the second and third embodiments, the bearing 53 of the photosensitive member 52 is in contact with and pressed against the belt unit housing 86, whereas in the fourth embodiment, the bearing 53 of the photosensitive member 52. Does not contact the belt unit housing 86 directly.

  In the fourth embodiment, two screw holes are formed in the side surface portion of the belt unit housing 86, and screws 162 and 162 used as fixing means are screwed into the two screw holes, respectively. Yes.

  FIG. 11 shows a state where the photoconductor 52 and the primary transfer roll 50 are aligned in the image forming apparatus 10 according to the fourth embodiment of the present invention. A positioning plate 164 used as a positioning member is attached to the belt unit housing 86. The positioning plate 164 has long holes 166 and 166 that are substantially parallel to each other, for example, in the vertical direction, and screws 162 and 162 that are passed through the long holes 166 and 166 are screwed to the belt unit housing 86. The positioning plate 164 is fixed to the belt unit housing 86. The positioning plate 164 can be moved in the direction of the long holes 166, 166, that is, for example, the longitudinal direction by loosening the screws 166, 166, and can be fixed to the belt unit housing 86 again at the moved position.

  A notch 168 is formed in the positioning plate 164. The notch 168 is formed with an edge 168a formed obliquely so as to be inclined in the direction opposite to the traveling direction of the intermediate transfer belt 14 from the vertical direction, and the vertical direction. And an edge portion 168b formed obliquely so as to be inclined in the traveling direction of the intermediate transfer belt 14. The bearings 53 of the photoconductor 52 are pressed against the edge portions 168 a and 168 b by the elastic body 144, so that the photoconductor 52 is positioned with respect to the positioning plate 164. In addition, the bearing 154 of the primary transfer roll 50 is pressed against the edge 168 a and the edge 168 b by the spring 156 (see FIG. 10), and the primary transfer roll 50 is positioned with respect to the positioning plate 164.

  Although only the positioning plate 164 on the near side is shown in FIG. 11, the positioning plate having the same shape as the positioning plate on the near side is also provided on the side surface on the back side of the belt unit housing 86 in the same manner as the positioning plate on the near side. It is attached by the method. Thus, in this embodiment, the positioning plate 164 is movably attached to the belt unit housing 86 used as a support member for supporting the intermediate transfer belt 14 used as the third process means. For this reason, the positional relationship between the intermediate transfer belt 14, the photosensitive member 52, and the primary transfer roll 50 is adjusted by moving at least one of the positioning plate 164 on the near side or the back side with respect to the belt unit housing 164. Can do.

  FIG. 11 shows only the positioning plate 164 for positioning the leftmost photosensitive member 52 and primary transfer roll 50, but the other three photosensitive members 52 and primary transfer roll 50 are shown. The three positioning plates to be positioned are provided on the near side and the far side of the belt unit housing 86, respectively.

  In the fourth embodiment described above, each positioning plate 164 is mounted on the belt unit housing 86 so as to be movable. However, each frame is attached to the frame of the image forming apparatus main body 12 and the housing of the image forming unit 48. The positioning plate 164 may be mounted so as to be movable.

  In the first to fourth embodiments described above, the image forming apparatus 10 has four image forming units 16 and forms a full color image by superimposing the images formed by the image forming units. Although the embodiment in which the invention is applied to the image forming apparatus has been described, the invention may be applied to an image forming apparatus that includes one image forming unit 16 and forms a single color image.

  As described above, the present invention has the first and second process means including, for example, a photoreceptor, an intermediate transfer belt, a transfer roll, etc., and the first and second process means are aligned. For example, the present invention can be applied to an image forming apparatus such as a copying machine, a facsimile machine, and a printer in which an image is formed.

1 is a front view showing a schematic configuration of an image forming apparatus according to a first embodiment of the present invention. 1 is a front view showing an image forming unit used in an image forming apparatus according to a first embodiment of the present invention. FIG. 3 is an explanatory diagram showing a drive system used in the image forming apparatus according to the first embodiment of the present invention. FIG. 2 is a cross-sectional view showing a drive system used in the image forming apparatus according to the first embodiment of the present invention and showing a BB cross section in FIG. 1. FIG. 2 is a cross-sectional view showing a state in which a belt unit used in the image forming apparatus according to the first embodiment of the invention is positioned, and showing a cross section taken along AA in FIG. It is a front view which shows the belt unit housing | casing used for the image forming apparatus which concerns on the 2nd Embodiment of this invention. FIG. 10 is an explanatory diagram illustrating a state in which a photoconductor and a transfer roll used in an image forming apparatus according to a second embodiment of the present invention are aligned. It is a front view which shows the belt unit housing | casing used for the image forming apparatus which concerns on the 3rd Embodiment of this invention. It is explanatory drawing explaining the state in which the photoconductor and transfer roll which are used for the image forming apparatus which concerns on the 3rd Embodiment of this invention are aligned. It is a front view which shows the belt unit used for the image forming apparatus which concerns on the 4th Embodiment of this invention. It is explanatory drawing explaining the state to which the photoconductor and transfer roll which are used for the image forming apparatus which concerns on the 4th Embodiment of this invention are aligned.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Image forming apparatus 12 Image forming apparatus main body 14 Intermediate transfer belt 15 Separating mechanism 32 Secondary transfer roll 48 Image forming units 49a, 49b, 49c, 49d Edge 50 Primary transfer roll 52 Photoconductor 53 Bearing 84 Belt unit 86 Belt unit Housing 88 Back side plate 88a Through hole 89 Front side plate 104 Drive frame 106 Drive gear 108 Motor 110 Bearing 116 Photosensitive gear 120 Belt gear 126 Pin 140 Support plate 142 Cam 144 Elastic body 154 Bearing 156 Spring 162 Screw 164 Positioning plate 166 Long hole

Claims (13)

An image forming apparatus main body;
A first unit provided with a first process means;
A second unit provided with second process means aligned with said first process means;
First positioning means for positioning the first unit with respect to the image forming apparatus main body;
Second positioning means for positioning the second unit with respect to the first unit;
An image forming apparatus comprising:   The image forming apparatus according to claim 1, wherein the first unit and the second unit are detachable from the main body of the image forming apparatus. A drive frame provided in the image forming apparatus main body and mounted with at least a part of a drive system for transmitting drive to at least one of the first process means or the second process means;
The image forming apparatus according to claim 1, wherein the first positioning unit is configured through the drive frame.   The image forming apparatus according to claim 1, further comprising a pressing unit that presses the second unit against the first unit. 5. The image forming apparatus according to claim 1, further comprising a separating unit that separates the first process unit and the second process unit. Third process means aligned with the first process means;
Third positioning means for positioning the third process means with respect to the first process means;
6. The image forming apparatus according to claim 1, further comprising:   The image forming apparatus according to claim 1, wherein the first process unit includes a belt, and the second process unit includes an image carrier.   The image forming apparatus according to claim 1, comprising a plurality of the second units. First process means used for at least one of imaging or sheet conveyance;
A second process means aligned with the first process means and used for at least one of imaging or sheet conveyance;
A positioning member in which the first and second process means are in contact with each other, and the first and second process means are positioned;
An image forming apparatus comprising:   The image forming apparatus according to claim 9, wherein the first and second process units are in contact with the positioning member at at least two locations. First pressing means for pressing the first process means against the positioning member;
Second pressing means for pressing the second process means against the positioning member;
The image forming apparatus according to claim 9, further comprising:   The image forming apparatus according to claim 9, wherein the positioning member supports at least one of the first or second process means. Third process means aligned with the first and second process means and used for at least one of image formation and sheet conveyance;
A support member for supporting the third process means;
Further comprising
The image forming apparatus according to claim 9, wherein the positioning member is movably attached to the support member.

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