JP2005221795A - Image forming unit and image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To eliminate the need to adjust the positioning of an image carrier in an image forming unit only. <P>SOLUTION: Side frames 100a and 100b are arranged almost parallel to each other in the direction in which an image carrier 50 and an intermediate transfer body 64 are rotated. The side frames 100a and 100b are connected together at three parts via protective covers 102a and 102b covering the upper part and the lower part, respectively, of the intermediate transfer body 64 and the shaft part 106 of the secondary transfer backup roller 72, thereby relatively positioning each part of the image forming unit 96. A primary transfer roll 66, a wrap-in roll 68, a wrap-out roll 70, a scraper backup roll 74, and brush backup roll 76 have play such that each of them rotates around its one end relative to the side frames 100a and 100b. The range of the play is restricted by the elastic protective covers 102a and 102b. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to an image forming unit and an image forming apparatus.

2. Description of the Related Art As an image forming apparatus, an image forming unit is configured by unitizing a photosensitive member and an intermediate transfer belt, and is detachable from an image forming apparatus main body.
In this type of image forming apparatus, when the image forming unit is not accurately positioned with respect to the main body of the image forming apparatus, the intermediate transfer belt may meander and the formed image becomes unstable. there were. In order to solve this problem, it is known that the position of the image forming unit with respect to the image forming apparatus main body is restrained by three engaging portions (Patent Document 1). In addition, it is known that an image forming unit is configured by increasing the coupling rigidity between a unit having a photoconductor and a unit having an intermediate transfer belt, thereby preventing the position of the image forming unit from deviating from the main body of the image forming apparatus. (Patent Document 2).

JP 2003-186372 A JP 2003-195729 A

  However, in the above conventional example, it is necessary to adjust the positioning of the photosensitive member and the intermediate transfer belt in the image forming unit alone, which may hinder the productivity of the image forming unit.

  SUMMARY An advantage of some aspects of the invention is that it provides an image forming unit and an image forming apparatus using the image forming unit, which can eliminate the need for positioning adjustment of the image carrier with a single image forming unit.

  In order to achieve the above object, a first feature of the present invention is that an image carrier formed in a belt shape, a plurality of rolls for supporting the image carrier to rotate, and the plurality of rolls The image forming unit includes a pair of side frames that support the image frame and a protective cover that is connected to the side frames and protects the image carrier, and has play between the side frames. Therefore, even if the positioning of the image carrier is not adjusted by the image forming unit alone, the image forming unit has play between the side frames, so that it has a degree of freedom in the twisting direction, and the image forming unit is an image forming apparatus. By mounting on the main body, the image forming unit can be deformed along the main body of the image forming apparatus, and each part of the image forming unit supported by the side frame is positioned (self-aligned) with respect to the main body of the image forming apparatus. ) That is, positioning adjustment with the image forming unit alone becomes unnecessary, and the productivity of the image forming unit can be improved.

  Preferably, the image carrier is an intermediate transfer member. Therefore, since the image forming unit is deformed along the image forming apparatus main body, the intermediate transfer member can be positioned without adjusting the positioning of the intermediate transfer member with the image forming unit alone.

  Preferably, the image forming apparatus further includes a photosensitive member on which an image is transferred to the intermediate transfer member. Therefore, since the image forming unit is deformed along the image forming apparatus main body, it is possible to position the photoconductor without adjusting the positioning of the photoconductor with the image forming unit alone.

  Preferably, the protective cover includes a first cover that protects an upper part of the image carrier and a second cover that protects a lower part of the image carrier. Therefore, the protective cover can protect the upper and lower portions of the image carrier, and can easily handle the image forming unit.

  Preferably, the first cover and the second cover are alternately fixed to the side frame. Therefore, the first cover and the second cover do not hinder the degree of freedom in the twisting direction of the image forming unit.

  Preferably, a part of the protective cover is loosely fitted to the side frame. Accordingly, since play can be provided between the protective cover and the side frame, each part of the image forming unit supported by the side frame is not affected by the freedom of the image forming unit in the twisting direction. Positioned relative to the forming apparatus body.

  Preferably, the protective cover is made of an elastic material. That is, the protective cover can absorb the force generated by the deformation of the image forming unit.

  The second feature of the present invention is that an image carrier formed in a belt shape, a plurality of rolls that support the image carrier to rotate, and a pair of rollers that support the plurality of rolls. An image forming unit having a side frame, a protective cover connected to the side frame and protecting the image carrier, and having play between the side frames, and an image forming unit in which the image forming unit is attached and detached The image forming apparatus includes an apparatus main body and positioning means for positioning the image forming unit and the image forming apparatus main body. Therefore, since the image forming unit and the image forming apparatus main body are positioned by the positioning unit, it is not necessary to adjust the positioning of the image forming unit alone, and the productivity of the image forming unit can be improved.

  Preferably, the positioning means includes a guide part provided in the image forming apparatus main body and a guided part provided in the image forming unit and guided by the guide part of the image forming apparatus main body. That is, the guided part of the image forming unit is guided by the guide part of the main body of the image forming apparatus, whereby the image forming unit is positioned while being deformed. Therefore, it is not necessary to adjust the positioning of the image forming unit alone, and the productivity of the image forming unit can be improved.

  Preferably, the guided portion of the image forming unit is provided on at least one of the plurality of rolls. Preferably, the image carrier is an intermediate transfer member, and the guided portion of the positioning unit supports the intermediate transfer member. Preferably, the image carrier is an intermediate transfer member, and further includes a photosensitive member on which an image is transferred to the intermediate transfer member, and the guided portion of the positioning unit supports the photosensitive member. To do. Preferably, the image forming unit further includes an intermediate transfer body cleaner that cleans the intermediate transfer body, and the guided portion of the positioning unit supports the intermediate transfer body cleaner. That is, regardless of which part of the image forming unit forms the guided portion with respect to the guide portion of the image forming apparatus main body, the image forming unit is positioned while being deformed along the guide portion of the image forming apparatus main body. Can do.

  According to the present invention, it is possible to eliminate the need for adjusting the positioning of the image carrier with a single image forming unit.

Next, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 shows an outline of an image forming apparatus 10 according to an embodiment of the present invention. The image forming apparatus 10 includes an image forming apparatus main body 12, and an opening / closing cover 16 that is rotatable about a rotation fulcrum 14 is provided on the upper portion of the image forming apparatus main body 12. For example, a one-stage sheet feeding unit 18 is disposed at a lower portion of 12.

  The paper feed unit 18 includes a paper feed unit main body 20 and a paper feed cassette 22 in which paper is stored. A feed roll 24 that feeds paper from the paper feed cassette 22 and a retard roll 26 that sprinkles the fed paper one by one are arranged in the upper vicinity of the rear end of the paper feed cassette 22.

  The conveyance path 28 is a sheet path from the feed roll 24 to the discharge port 30, and this conveyance path 28 is in the vicinity of the back side (right side surface in FIG. 1) of the image forming apparatus main body 12 and is described later from the sheet feeding unit 18. The fixing device 90 is formed substantially vertically. A secondary transfer roll 80 and a secondary transfer backup roll 72, which will be described later, are disposed on the upstream side of the fixing device 90 in the conveyance path 28, and the registration roll 32 is located upstream of the secondary transfer roll 80 and the secondary transfer backup roll 72. Is arranged. In addition, a discharge roll 34 is disposed in the vicinity of the discharge port 30 of the conveyance path 28.

  Accordingly, the sheet fed from the sheet feeding cassette 22 of the sheet feeding unit 18 by the feed roll 24 is turned by the retard roll 26 and only the uppermost sheet is guided to the conveyance path 28 and temporarily stopped by the registration roll 32. The toner image is transferred between a secondary transfer roll 80 and a secondary transfer backup roll 72, which will be described later, and the transferred toner image is fixed by the fixing device 90, and the discharge port 34 discharges the discharge port 30. Are discharged to a discharge portion 36 provided on the upper portion of the opening / closing cover 16. The discharge portion 36 has a low discharge port portion and is inclined so as to gradually increase toward the front direction (left direction in FIG. 1).

  In the image forming apparatus main body 12, for example, a rotary developing device 38 is disposed at a substantially central portion. The rotary developing device 38 includes developing units 42a to 42d that respectively form toner images of four colors of yellow, yellow, magenta, cyan, and black in the developing unit main body 40. It rotates counterclockwise (counterclockwise in FIG. 1) about the rotary developing device center 44. Each of the developing units 42a to 42d has developing rolls 46a to 46d, and is pressed in the normal direction of the developing unit main body 40 by elastic bodies 48a to 48d such as coil springs.

  The rotary developing device 38 is arranged so as to rotate, for example, around a rotation support shaft 49 so that an image carrier 50 made of, for example, a photosensitive member comes into contact therewith, and the developing rolls 46 a to 46 d abut against the image carrier 50. When not in contact, a part of each outer periphery protrudes, for example, 2 mm from the outer periphery of the developing device main body 40 in the radial direction. Further, a tracking roll (not shown) having a diameter slightly larger than the diameter of the developing rolls 46a to 46d is provided at both ends of each of the developing rolls 46a to 46d so as to rotate coaxially with the developing rolls 46a to 46d. Yes. That is, the developing rolls 46a to 46d of the developing units 42a to 42d are arranged on the outer periphery of the developing unit main body 40 at intervals of 90 ° around the rotary developing device center 44, and the tracking rolls of the developing rolls 46a to 46d are imaged. A latent image on the image carrier 50 is abutted against flanges (not shown) provided at both ends of the carrier 50, and a predetermined gap is formed between the developing rollers 46a to 46d and the image carrier 50. Develop with each color toner.

Below the image carrier 50, a charging device 52 made of, for example, a charging roll for uniformly charging the image carrier 50 is provided. An image carrier cleaner 54 is held on the image carrier 50 so as to hang from the rotation support shaft 49, and the image carrier 50 and the image carrier cleaner 54 are integrated. The image carrier cleaner 54 includes, for example, a cleaning blade 56 that scrapes waste toner remaining on the image carrier 50 after primary transfer, and a toner collection bottle 58 that collects waste toner scraped by the cleaning blade 56. .
The back side (right side in FIG. 1) of the toner collection bottle 58 is formed with a rib or the like, for example, and is curved to form a part of the conveyance path 28 so that the paper is smoothly conveyed.

  On the lower back side of the rotary developing device 38, an exposure device 60 for writing a latent image on the image carrier 50 charged by the charging device 52 with a light beam such as a laser beam is disposed. Further, an intermediate transfer device 62 is provided above the rotary developing device 38. The toner image visualized by the rotary developing device 38 is primarily transferred at the primary transfer position and conveyed to a secondary transfer position described later.

The intermediate transfer device 62 includes an intermediate transfer member 64 such as an intermediate transfer belt, a primary transfer roll 66, a wrap-in roll 68, a wrap-out roll 70, a secondary transfer backup roll 72, a scraper backup roll 74, and a brush backup roll 76. . The intermediate transfer body 64 has elasticity, for example, and is stretched substantially flat so as to have a long side and a short side above the rotary developing device 38. The long side on the upper surface side of the intermediate transfer body 64 is stretched so as to be substantially parallel to, for example, the discharge unit 36 provided on the upper portion of the image forming apparatus main body 12. The intermediate transfer member 64 includes a wrap-in roll 68 disposed upstream of the primary transfer roll 66 below the long side of the intermediate transfer member 64, and a wrap-out roll 70 disposed downstream of the primary transfer roll 66. The image bearing member 50 has a primary transfer portion (image bearing member wrap region) that abuts on the image bearing member 50 in a lap shape. The image bearing member 50 is wound around a predetermined range and is driven by the rotation of the image bearing member 50. As described above, the intermediate transfer member 64 is primarily transferred by the primary transfer roll 66 while superimposing the toner images on the image carrier 50 in the order of, for example, yellow, magenta, cyan, and black, and the primary transferred toner image will be described later. It is conveyed toward the secondary transfer roll 80. The wrap-in roll 68 and the wrap-out roll 70 are separated from the image carrier 50.
Thus, the intermediate transfer body 64 is stretched by five rolls of the wrap-in roll 68, the wrap-out roll 70, the secondary transfer backup roll 72, the scraper backup roll 74, and the brush backup roll 76, and the primary transfer roll 66, the toner image on the image carrier 50 is transferred.

Further, a flat surface portion (short side) is formed on the back side (right side surface in FIG. 1) of the intermediate transfer body 64 by a wrap-out roll 70 and a secondary transfer backup roll 72, and this flat surface portion is subjected to secondary transfer. It faces the conveyance path 28 as a part.
In the secondary transfer portion, the wrap-out roll 70 is arranged so that the intermediate transfer body 64 and the conveyance path 28 are at an angle of 12 °, for example.

  The scraper backup roll 74 assists the scraper 84 described later to scrape waste toner remaining on the intermediate transfer body 64 after the secondary transfer, and the brush backup roll 76 wastes remaining on the intermediate transfer body 64 after the secondary transfer. A brush roll 86 described later assists in scraping off the toner.

  Above the long side of the intermediate transfer body 64, a sensor 78 such as a reflective photosensor is provided by being fixed to the back surface (inside) of the opening / closing cover 14. The sensor 78 reads a toner patch formed on the intermediate transfer body 64, detects the position of the intermediate transfer body 64 in the rotation direction, and detects the toner density.

  A secondary transfer roll 80 is opposed to the secondary transfer backup roll 72 of the intermediate transfer device 62 with the conveyance path 28 interposed therebetween. That is, the secondary transfer position in the secondary transfer portion is between the secondary transfer roll 80 and the secondary transfer backup roll 72, and the secondary transfer roll 80 is intermediate with the assistance of the secondary transfer backup roll 72. The toner image primarily transferred to the transfer body 64 is secondarily transferred onto the paper at the secondary transfer position. Here, the secondary transfer roll 80 is separated from the intermediate transfer body 64 while the intermediate transfer body 64 rotates three times, that is, while the toner images of three colors of yellow, magenta, and cyan are transported. When the image is transferred, it comes into contact with the intermediate transfer member 64. In addition, a predetermined potential difference is generated between the secondary transfer roll 80 and the secondary transfer backup roll 72. For example, when the secondary transfer roll 80 is set to a high voltage, the secondary transfer backup 80 The roll 72 is connected to a ground (GND) or the like.

An intermediate transfer member cleaner 82 is provided at the end of the intermediate transfer member 64 on the side opposite to the image carrier. The intermediate transfer body cleaner 82 includes a scraper 84, a brush roll 86, a toner collection bottle 88, and a rotation support shaft 89, and swings about the rotation support shaft 89. For example, the scraper 84 scrapes off and cleans waste toner remaining on the intermediate transfer member 64 after the secondary transfer.
The brush roll 86 further scrapes off the waste toner remaining after cleaning by the scraper 84. The toner collection bottle 88 collects the toner scraped by the scraper 84 and the brush roll 86. The scraper 84 is made of, for example, a thin plate made of stainless steel, and is applied with a voltage having a polarity opposite to that of the toner. The brush roll 86 is made of, for example, an acrylic brush that has been subjected to a conductive treatment. While the intermediate transfer member 64 conveys the toner image, the scraper 84 and the brush roll 86 are separated from the intermediate transfer member 64 and come into contact with the intermediate transfer member 64 at a predetermined timing. Has been.

  The intermediate transfer device 62, the image carrier 50, the charging device 52, the image carrier cleaner 54, and the intermediate transfer member cleaner 82 are integrated to form a part of an image forming unit 96 described later. Further, the image carrier 50, the charging device 52 and the image carrier cleaner 54 are integrated to form an image carrier unit 97. The image carrier unit 97 is detachably attached to the intermediate transfer device 62. The intermediate transfer device 62 is attached with the image carrier unit 97, whereby the intermediate transfer member 64 is set to a predetermined tension. At the same time, a primary transfer portion is formed.

  A fixing device 90 is disposed above the secondary transfer position. The fixing device 90 includes a heating roll 92 and a pressure roll 94, fixes the toner image secondarily transferred to the sheet by the secondary transfer roll 80 and the secondary transfer backup roll 72, and fixes the toner image to the discharge roll 34. Transport toward.

Details of the image forming unit 96 are shown in FIGS.
The image forming unit 96 includes a pair of side frames 100a and 100b provided on the left and right (left and right in FIG. 3), a pair of protective covers 102a and 102b provided on the top and bottom (up and down in FIG. 3), an intermediate transfer device 62, an image. The carrier 50, the charging device 52, the image carrier cleaner 54, and the intermediate transfer body cleaner 82 are integrated.
The intermediate transfer body 64 is supported so as to be rotated by five rolls of a secondary transfer backup roll 72, a wrap-in roll 68, a wrap-out roll 70, a scraper backup roll 74, and a brush backup roll 76. The toner image carried on the carrier 50 is transferred. Each of the primary transfer roll 66, the wrap-in roll 68, the wrap-out roll 70, the scraper backup roll 74, and the brush backup roll 76 is provided with bearings 104 at both ends, and is supported by the side frames 100a and 100b via the bearings 104. The The secondary transfer backup roll 72 has a shaft portion 106 and a rotating portion 108 that rotates around the shaft portion 106, and both ends of the shaft portion 106 are side frames 100 a and 100 b by fixing members 110 and 110 such as screws. It is fixed to each.

  The side frame 100a has a through hole 112 through which the rotation support shaft 49 of the image carrier 50 passes and a through hole 114 through which the rotation support shaft 89 of the intermediate transfer member cleaner 82 passes. The support shaft 89 protrudes to the side. A concave portion 116 that engages with a protrusion 140 (to be described later) of the protective cover 102a is provided on the upper side of the side frame 100a on the image carrier 50 side, and a fixing portion (to be described later) of the protective cover 102a on the intermediate transfer member cleaner 82 side upper portion. A hole 120 in which 142 is fixed by the fixing member 110 is provided. A concave portion 122 that engages with a projection 144 (described later) of the protective cover 102b is provided in the lower portion of the side frame 100a on the intermediate transfer member cleaner 82 side, and a fixing portion (described later) of the protective cover 102b on the lower portion on the image carrier 50 side. A hole 126 is provided in which 146 is fixed by the fixing member 110.

  Further, the side frame 100 a is provided with a fixing portion 128 that fixes one end of the shaft portion 106 of the secondary transfer backup roll 72 with the fixing member 110. Further, inside the side frame 100a, a receiving portion 130 (in FIG. 4) that supports one end of a wrap-in roll 68, a wrap-out roll 70, a scraper backup roll 74, and a brush backup roll 76 from the side via a bearing 104. Side frames 100b) are provided. Note that one end of the secondary transfer backup roll 72 is supported by the side frame 100a via a bearing 104 and a holder (not shown).

  The side frame 100 b passes through a rotation support shaft 49 of the image carrier 50 and a notch 134 that supports one end of the rotation support shaft 49 via a bearing 132 and a rotation support shaft 89 of the intermediate transfer member cleaner 82. And a rotation support shaft 49 and a rotation support shaft 89 project laterally. A concave portion 116 (see FIG. 6) that engages a later-described protrusion 140 of the protective cover 102a is provided on the upper side of the side frame 100b on the image carrier 50 side. A hole 120 is provided in which a fixing part 142 described later is fixed by the fixing member 110. A concave portion 122 that engages with a projection 144 described later of the protective cover 102b is provided at the lower portion of the side frame 100b on the intermediate transfer member cleaner 82 side, and a fixing portion of the protective cover 102b described later is provided at the lower portion of the image carrier 50 side. A hole 126 is provided in which 146 is fixed by the fixing member 110.

  The side frame 100 b is provided with a fixing portion 128 that fixes one end of the shaft portion 106 of the secondary transfer backup roll 72 with the fixing member 110. Further, inside the side frame 100b, a receiving portion 130 (FIG. 4) that supports one end of a wrap-in roll 68, a wrap-out roll 70, a scraper backup roll 74, and a brush backup roll 76 from the side via a bearing 104. Are provided. Note that one end of the primary transfer roll 66 is supported by the side frame 100b via a bearing 104 and a holder (not shown).

  The protective cover 102a includes a cover main body 135a, a gripping portion 136, a convex portion 138, protrusions 140 and 140, and fixing portions 142 and 142. The cover main body 135a is made of, for example, ABS resin and has elasticity, and covers the intermediate transfer member 64 and the intermediate transfer member cleaner 82. The gripper 136 is made of, for example, a flexible member, and is provided on the upper surface of the cover main body 135a so that an operator can grip the image forming unit 96. The convex portion 138 is formed integrally with the cover main body 135a, for example, protrudes so as to face the fixing device 90 (FIG. 1), and restricts the movement of the foreign matter placed on the upper surface of the cover main body 135a. The protrusions 140 and 140 engage with the recesses 116 and 116 of the side frames 100a and 100b, respectively, and the fixing portions 142 and 142 are fixed to the holes 120 and 120 of the side frames 100a and 100b by the fixing members 110 and 110, respectively. Is done.

  The protective cover 102b includes a cover main body 135b, protrusions 144 and 144, and fixing portions 146 and 146. The cover main body 135b is made of, for example, ABS resin and has elasticity, and is curved so as to cover the intermediate transfer member 64 and the intermediate transfer member cleaner 82. The protrusions 144 and 144 engage with the recesses 122 and 122 of the side frames 100a and 100b, respectively, and the fixing portions 146 and 146 are fixed to the holes 126 and 126 of the side frames 100a and 100b by the fixing members 110 and 110, respectively. Is done.

That is, the side frames 100a and 100b are arranged substantially parallel to the rotation direction of the image carrier 50 and the intermediate transfer member 64, and the protective covers 102a and 102b and the secondary transfer covering the upper and lower portions of the intermediate transfer member 64, respectively. The shafts 106 of the backup roll 72 are connected to each other at three locations to determine the relative positions of the respective parts constituting the image forming unit 96, and the image carrier 50, the intermediate transfer member 64, and the intermediate transfer member cleaner 82. Cover the sides. Further, since both ends of the shaft portion 106 of the secondary transfer backup roll 72 are fixed to the side frames 100a and 100b in the image forming unit 96, the vicinity of the secondary transfer position of the intermediate transfer body 64 is exposed in a stable state. Yes.
On the other hand, the protective covers 102a and 102b have elasticity, and one ends are alternately fixed to the side frames 100a and 100b. Further, the primary transfer roll 66, the wrap-in roll 68, the wrap-out roll 70, the scraper backup roll 74, and the brush backup roll 76 are supported by the side frames 100a and 100b via bearings 104, respectively, and the side frames 100a and 100b are supported. Have play against. As described above, the primary transfer roll 66, the wrap-in roll 68, the wrap-out roll 70, the scraper backup roll 74, and the brush backup roll 76 have a play that turns with respect to the side frames 100a and 100b around one end thereof. However, the range of this play is limited by the protective covers 102a and 102b.
That is, the image forming unit 96 has a degree of freedom in which twisting occurs while the vicinity of the secondary transfer position of the intermediate transfer body 64 is exposed in a stable state.

Next, the operation of the above embodiment will be described.
When the image forming signal is sent, the image carrier 50 is uniformly charged by the charging device 52, and a light beam is emitted from the exposure device 60 to the charged image carrier 50 based on the image signal. Light rays from the exposure device 60 expose the surface of the image carrier 50 to form a latent image. The latent image of the image carrier 50 formed by the exposure device 60 is developed with yellow, magenta, cyan, and black toner images by the rotary developing device 38 and is primarily transferred onto the intermediate transfer member 64. In the primary transfer, waste toner remaining on the image carrier 50 is scraped off and collected by the image carrier cleaner 54.

  On the other hand, the paper stored in the paper feed cassette 22 by a paper feed signal or the like is sent out by the feed roll 24, is turned by the retard roll 26, is guided to the transport path 28, is temporarily stopped by the registration roll 32, and the timing is reached. As a result, it is guided between the secondary transfer roll 80 and the secondary transfer backup roll 72. When the sheet is guided between the secondary transfer roll 80 and the secondary transfer backup roll 72, the toner image primarily transferred to the intermediate transfer body 64 is transferred to the sheet by the secondary transfer roll 80 and the secondary transfer backup roll 72. Secondary transfer. After the secondary transfer, the waste toner remaining on the intermediate transfer member 64 is scraped off and collected by the intermediate transfer member cleaner 82.

  The sheet on which the toner image has been transferred is guided to the fixing device 90, and the toner image is fixed by the thermal pressure of the heating roll 92 and the pressure roll 94. The sheet on which the toner image is fixed is discharged from the discharge port 30 to the discharge unit 36 by the discharge roll 34.

Next, a method for attaching and detaching the image forming unit 96 of the above embodiment will be described.
FIG. 7 shows a state in which the image forming unit 96 is removed from the image forming apparatus main body 12. When the image forming unit 96 is removed from the image forming apparatus main body 12, the image forming apparatus 10 is configured such that the opening / closing cover 16 of the image forming apparatus main body 12 is rotated about the rotation fulcrum 14, thereby Open the top. The image forming unit 96 is disposed such that the intermediate transfer device 62 and the image carrier 50 are positioned between the fixing device 90 and the rotary developing device 38, and a space between the fixing device 90 and the rotary developing device 38. Through the image forming apparatus main body 12 and obliquely forward (left obliquely upward in FIG. 7). In this way, the image forming unit 96 is removed without opening the transport path 28.
The image forming unit 96 is detachable from the image forming apparatus main body 12, and is attached to the image forming apparatus main body 12 by opening the opening / closing cover 16.
The image carrier unit 97 is attached and detached with the image forming unit 96 detached from the image forming apparatus main body 12.

  In FIG. 8, the direction in which the image forming unit 96 is mounted on the image forming apparatus main body 12 is schematically shown. The image forming unit 96 is attached to and detached from the image forming apparatus main body 12 in a predetermined direction by being guided by the main positioning unit 148 and the auxiliary positioning unit 150 by holding the holding unit 136. For example, when the gripper 136 is held from above, the image forming unit 96 is in an insertion posture (posture shown in FIG. 8) into the image forming apparatus main body 12. That is, when the image forming unit 96 is lifted upward by gripping the gripping portion 136, the image forming unit 96 is tilted and held so that the image carrier cleaner 54 is positioned below. ing.

  The main positioning unit 148 includes, for example, a guide groove 152 provided on the image forming apparatus main body 12 side and a rotation support shaft 49 of the image carrier 50 protruding to the side of the image forming unit 96. The rotation support shaft 49 is formed in a columnar shape that engages with the guide groove 152, and moves along the guide groove 152. The auxiliary positioning unit 150 includes, for example, an auxiliary groove 154 provided on the image forming apparatus main body 12 side and a rotation support shaft 89 of the intermediate transfer member cleaner 82 protruding to the side of the image forming unit 96. The rotation support shaft 89 is formed in a cylindrical shape that engages with the auxiliary groove 154, for example, and moves along the auxiliary groove 154.

  In the guide groove 152, the contact guide groove 156 is formed at the lower portion at an angle A with respect to the horizontal line, and the movement guide groove 158 is formed at the upper portion at an angle B with respect to the horizontal line. In addition, the auxiliary groove 154 has a contact guide separation groove 160 formed at the lower portion at an angle A with respect to the horizontal line, and a movement auxiliary guide groove 162 formed at the upper portion at an angle B with respect to the horizontal line. The angle A is, for example, 70 °, and the angle B is, for example, 55 °. Therefore, when the rotation support shaft 49 and the rotation support shaft 89 are moved along the contact / separation guide groove 156 and the contact / separation auxiliary guide groove 160, respectively, the image forming unit 96 is contacted and separated from the substantially tangential direction of the rotary developing device 38. Move in the direction. When the rotation support shaft 49 and the rotation support shaft 89 are moved along the movement guide groove 158 and the movement auxiliary guide groove 162, respectively, the image forming unit 96 moves in a substantially tangential direction passing through the development position of the rotary developing device 38. To do.

In the image forming unit 96, the relative positions of the respective parts constituting the image forming unit 96 are determined by the side frames 100a and 100b. Accordingly, the rotation support shaft 49 and the rotation support shaft 89 move along the guide groove 152 and the auxiliary groove 154, respectively, so that each part constituting the image forming unit 96 is in a predetermined position with respect to the image forming apparatus main body 12. Is positioned. In other words, the image forming unit 96 is mounted on the image forming apparatus main body 12 without adjusting the positioning of the intermediate transfer body 64 and the image carrier 50 with the image forming unit 96 alone, so that the secondary transfer roll 80 can be mounted. The position of the image carrier 50 with respect to the secondary transfer backup roll 72 and the rotary developing device 38 can be determined, and meandering of the intermediate transfer member 64 can be prevented.
Further, as described above, the intermediate transfer member cleaner 82 swings about the rotation support shaft 89, and the image carrier 50 rotates about the rotation support shaft 49 to drive the intermediate transfer member 64. That is, since the shaft driven from the image forming apparatus main body 12 side is directly positioned with respect to the image forming apparatus main body 12, the image forming unit 96 is prevented from being deformed by the driving force for driving the image forming unit 96. be able to.

  In the above embodiment, the image forming unit 96 includes the image carrier 50 made of, for example, a photoconductor and the intermediate transfer member 64 made of an intermediate transfer belt. However, the present invention is not limited to this. At least one of the intermediate transfer members may have a belt shape and may be supported by a plurality of rolls. Further, the image forming apparatus 10 may have one or more image carriers formed in a belt shape.

  In addition, the image forming unit 96 is guided in any combination of parts of the image forming unit 96 such as part of the side frames 100a and 100b and part of a plurality of rolls that support the intermediate transfer body 64. The groove 152 and the auxiliary groove 154 may be guided.

1 is a side view of an image forming apparatus according to an embodiment of the present invention. 1 is a perspective view showing an image forming unit used in an image forming apparatus according to an embodiment of the present invention. 1 is an exploded perspective view showing an image forming unit used in an image forming apparatus according to an embodiment of the present invention. FIG. 3 is an exploded perspective view of the image forming unit used in the image forming apparatus according to the embodiment of the present invention when viewed from below without the protective cover. FIG. 3 is an exploded perspective view showing a connection between a lower protective cover and a side frame of the image forming unit. FIG. 6 is an enlarged view showing engagement between a protective cover on the upper side of the image forming unit and a concave portion of the side frame. FIG. 2 is a side view showing a state in which the image forming unit according to the embodiment of the present invention is detached from the image forming apparatus main body. FIG. 3 is a side view schematically showing a direction in which the image forming unit is mounted on the image forming apparatus main body.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Image forming apparatus 12 Image forming apparatus main body 14 Rotation fulcrum 16 Opening / closing cover 38 Rotary developing device 49 Rotating spindle 50 Image carrier 52 Charging device 54 Image carrier cleaner 60 Exposure device 62 Intermediate transfer device 64 Intermediate transfer member 66 Primary transfer Roll 68 Wrap-in roll 70 Wrap-out roll 72 Secondary transfer backup roll 74 Scraper backup roll 76 Brush backup roll 80 Secondary transfer roll 82 Intermediate transfer body cleaner 89 Rotating spindle 96 Image forming units 100a and 100b Side frames 102a and 102b Protection Cover 104 Bearing 106 Shaft portion 108 Rotating portion 110 Fixed member 112, 114 Through hole 116, 122 Recess 120, 126 Hole 128, 142, 146 Fixed portion 135a Cover body 140, 144 Protrusion 148 Main position Determining means 150 auxiliary positioning means 152 guiding groove 154 the auxiliary grooves 156 contact and separation guide groove 158 moves the guide groove 160 separable auxiliary guide groove 162 moves the auxiliary guide groove

Claims (13)

  An image carrier formed in a belt shape, a plurality of rolls for supporting the image carrier to rotate, a pair of side frames for supporting the plurality of rolls, and the image carrier coupled to the side frames. An image forming unit comprising a protective cover for protecting a body and having play between the side frames.   2. The image forming unit according to claim 1, wherein the image carrier is an intermediate transfer member.   3. The image forming unit according to claim 2, further comprising a photosensitive member on which an image is transferred to the intermediate transfer member.   The said protective cover has a 1st cover which protects the upper part of the said image carrier, and a 2nd cover which protects the lower part of the said image carrier, The Claim 1 thru | or 3 characterized by the above-mentioned. Image forming unit.   The image forming unit according to claim 4, wherein the first cover and the second cover are alternately fixed to the side frame.   6. The image forming unit according to claim 1, wherein a part of the protective cover is loosely fitted to the side frame.   The image forming unit according to claim 1, wherein the protective cover is made of an elastic material.   An image carrier formed in a belt shape, a plurality of rolls for supporting the image carrier to rotate, a pair of side frames for supporting the plurality of rolls, and the image carrier coupled to the side frames. An image forming unit having a protective cover for protecting a body and having play between the side frames, an image forming apparatus main body to which the image forming unit is attached and detached, the image forming unit, and the image forming apparatus main body An image forming apparatus.   The positioning means includes a guide portion provided in the image forming apparatus main body and a guided portion provided in the image forming unit and guided by the guide portion of the image forming apparatus main body. Item 9. The image forming apparatus according to Item 8.   The image forming apparatus according to claim 8, wherein the guided portion of the image forming unit is provided on at least one of the plurality of rolls.   11. The image forming apparatus according to claim 9, wherein the image bearing member is an intermediate transfer member, and a guided portion of the positioning unit supports the intermediate transfer member.   The image carrier is an intermediate transfer member, and further includes a photosensitive member on which an image is transferred to the intermediate transfer member, and a guided portion of the positioning unit supports the photosensitive member. The image forming apparatus according to claim 9 or 10.   13. The image forming unit further includes an intermediate transfer body cleaner for cleaning the intermediate transfer body, and the guided portion of the positioning unit supports the intermediate transfer body cleaner. Image forming apparatus.

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