JP2016173560A - Image forming unit and image forming apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To stably convey toner having large particle size.SOLUTION: Binder toner remaining on a photoreceptor drum 7 is scraped off by a cleaning blade 64 into a cleaner 8. A conveyance screw 65 rotates to sequentially convey the remaining toner from a rear end to a front end of an image forming unit 6, and conveys it to a waste toner collection bag 68 arranged in an upper toner hopper 50 via a conveyance pipe 43. The conveyance pipe 43 is arranged at least partially on the side of a side face of the outer frame 40 and outside the outer frame 40, while a shape of a connection part protruding from the side face of the outer frame 40 is formed to be inclined with respect to a plane formed by the side face.SELECTED DRAWING: Figure 4

Description

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

  Conventionally, in an electrophotographic image forming apparatus, a photosensitive drum of a developing device is uniformly charged and initialized, a latent image is formed on the photosensitive drum by optical writing, and the latent image is converted into a toner image (development). Then, the toner image is directly or indirectly transferred to a printing medium and fixed by a fixing device.

  In the image forming apparatus, after the developed toner image is transferred onto the photosensitive drum, the toner remaining on the photosensitive drum is collected by a cleaning device, and a pipe having a spiral body such as a coil spring is passed through the pipe. Accordingly, a technique for conveying residual toner to a collection box or the like by rotating the spiral body is disclosed (for example, see Patent Document 1).

  FIG. 7 is a schematic diagram for explaining a residual toner collecting path in a conventional image forming apparatus. In FIG. 7, the toner remaining on the photosensitive drum 80 is scraped off into the cleaner 81 by a cleaning blade (not shown), and is indicated by arrows A, B, and C by a spiral body (such as a coil spring) that rotates in the transport pipe 82a. Are sequentially conveyed in the direction, and finally collected in a collection bag 84a or the like in the toner hopper 83.

  FIG. 8 is a schematic diagram for explaining another example of the residual toner collecting path in the conventional image forming apparatus. In FIG. 8, the toner remaining on the photosensitive drum 80 is scraped off into the cleaner 81 by a cleaning blade (not shown) and is rotated in the directions of arrows a and b by a spiral body (coil spring or the like) that rotates in the transport pipe 82b. The toner is sequentially conveyed and finally collected in a collection box 84b or the like in the toner hopper 83.

JP 2010-20117 A

  However, in the above-described prior art, the conveyance pipes 82a and 82b, which are the residual toner conveyance path, are long and have a large number of bent portions. Unexpected failure due to deformation of the spiral when the tip of the spiral is pushed back, such as when the smooth rotation of the spiral is interrupted and illegal driving occurs, or the transport destination space is full of residual toner. There is a problem that there is a risk of causing.

  In order to prevent this, it is conceivable to increase the conveying force while preventing the deformation of the helical body by giving rigidity to the helical bodies inside the conveying pipes 82a and 82b. There arises a problem that the spiral body that alternately receives compressive stress tends to be broken particularly at the bent portion.

  Furthermore, in the above-described image forming apparatus, a thermal transfer print sheet is prepared by fixing an image to be transferred to a transfer medium on a peelable sheet and a transfer base material (binder toner) made of an adhesive thermoplastic resin. Is possible. In this case, instead of one of the mounted color toners (for example, black (K)), a toner cartridge containing a binder toner is mounted. Since the binder toner has a larger particle size than that of a normal toner, the above-described problem becomes more remarkable.

  Therefore, an object of the present invention is to stably convey even a toner having a large particle diameter.

  An image forming unit according to the present invention includes a toner storage chamber in which toner is stored, a photosensitive drum on which an electrostatic latent image is formed and supplied with toner from the toner storage chamber, and a removal from the photosensitive drum. A transport pipe for transporting the residual toner to the toner storage chamber, and an exterior frame that configures the toner storage chamber and stores the photosensitive drum, and at least a part of the transport pipe is the The outside of the exterior frame is routed on the side surface side of the exterior frame, and the shape of the connecting portion protruding from the side surface of the exterior frame is formed so as to be inclined with respect to the plane formed by the side surface. It is characterized by.

  An image forming apparatus according to the present invention is an image forming apparatus that is detachably provided with an image forming unit that develops a toner image. The image forming unit includes a toner storage chamber that stores toner and an electrostatic latent image. A photosensitive drum formed and supplied with toner from the toner storage chamber, a transfer pipe for transferring residual toner removed from the photosensitive drum to the toner storage chamber, and the toner storage chamber And an exterior frame that accommodates the photosensitive drum, and at least a part of the transport pipe is routed outside the exterior frame on the side surface side of the exterior frame, and the side surface of the exterior frame The connecting portion protruding from the side is formed so as to be inclined with respect to a plane formed by the side surface.

  According to the present invention, even a toner having a large particle diameter can be stably conveyed.

1 is a cross-sectional view illustrating an internal configuration of an image forming apparatus 1 according to an embodiment of the present invention. FIG. 2 is a perspective view showing an external structure of an image forming unit 6 according to the present embodiment. It is a side view showing the appearance structure of the image forming unit 6 according to the present embodiment. It is sectional drawing which shows the structure of the image forming unit 6 by this embodiment. FIG. 5 is a schematic diagram for explaining a recovery path for residual toner in the image forming apparatus 1 according to the present embodiment. FIG. 5 is a schematic diagram for explaining a recovery path for residual toner in the image forming apparatus 1 according to the present embodiment. FIG. 10 is a schematic diagram for explaining a residual toner collecting path in a conventional image forming apparatus. FIG. 10 is a schematic diagram for explaining another example of a residual toner collecting path in a conventional image forming apparatus.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

A. Configuration of Embodiment FIG. 1 is a cross-sectional view showing an internal configuration of an image forming apparatus 1 according to an embodiment of the present invention. In the figure, the image forming apparatus 1 according to the present embodiment is not a system that directly transfers a toner image onto a sheet (a printing medium), but temporarily transfers the toner image onto an intermediate transfer belt, and then vertically extends to a secondary transfer unit. The toner image is secondarily transferred onto the conveyed paper via an intermediate transfer belt. However, the present invention is not limited to the secondary transfer method, and can be applied to other transfer methods such as a method of directly transferring a toner image onto a sheet.

  The image forming apparatus 1 includes an image forming unit 2, a duplex printing conveyance unit 3, a paper feeding unit 4, and a fixing unit 5. The image forming unit 2 has a configuration in which four image forming units 6 (6-1, 6-2, 6-3, 6-4) are arranged in a multistage manner, and can be attached and detached for each image forming unit 6. It is configured. The three image forming units 6-1, 6-2, and 6-3 form a monocolor image using magenta (M), cyan (C), and yellow (Y) color toners that are subtractive three primary colors, respectively. To do. The fourth image forming unit 6-4 following the three image forming units 6-1, 6-2, 6-3 forms a black (K) monochrome image. These four color toner images are overlaid on the paper to form a full color image.

  The image forming units 6-1 to 6-4 have the same configuration except for the color and type of toner stored in the toner storage chamber 90. Therefore, hereinafter, the configuration of the image forming unit 6 will be described by taking the image forming unit 6-4 as an example.

  The image forming unit 6 includes a photosensitive drum 7 at the bottom. The peripheral surface of the photosensitive drum 7 is made of, for example, an organic photoconductive material. A developing device 11 including a cleaner 8, a charging roller 9, an optical writing head 10, a developing roller 12, and the like is disposed in contact with or around the periphery of the photosensitive drum 7.

  Further, the image forming unit 6 is provided with a toner storage chamber 90 in the upper portion, and as shown by M, C, Y, and K in the drawing, magenta (M), cyan (C), yellow (Y), black ( One of the toners K) is stored. The intermediate portion is provided with a toner replenishing mechanism that replenishes toner from the upper portion (toner storage chamber 90) toward the lower portion (developer 11).

  The developing unit 11 includes the developing roller 12 described above in the lower side opening, a toner stirring member, a toner supply roller 13 for supplying toner to the developing roller 12, and a toner placed on the developing roller 12. A doctor blade or the like that regulates the layer to a certain layer thickness is provided. An optical writing head 10 on the main device side is disposed in the vicinity of the upper surface located between the charging roller 9 and the developing device 11 of the photosensitive drum 7.

  In the present embodiment, the image forming units 6-1 to 6-4 are each integrally configured to replenish toner in the toner storage chamber 90 or replace the toner stored in the toner storage chamber 90. The image forming units 6-1 to 6-4, in which the photosensitive drum 7, the cleaner 8, the charging roller 9, the developing roller 12 of the developing device 11, and the toner supply roller 13 are arranged, are attached and detached. Thus, the toner is replenished or replaced.

  Further, as described above, when a thermal transfer print sheet is to be created, instead of at least one of the image forming units 6-1 to 6-4 (for example, the black (K) image forming unit 6-4), An image forming unit containing a binder toner made of a thermoplastic resin can be mounted.

  By the way, when the image forming unit 6 is mounted, the image forming unit 2 has an intermediate transfer belt 14 separate from the image forming unit 6 in proximity to the lower surface of the photosensitive drum 7 in the image forming unit 6. Configured to be located. The primary transfer roller 15 is pressed toward the lower surface of the photosensitive drum 7 with the intermediate transfer belt 14 interposed therebetween.

  The intermediate transfer belt 14 is made of a conductive sheet-like member made of resin containing conductive carbon or an ion conductive substance, and has a flat loop shape from substantially the left and right sides of the figure at the center of the main unit. This is an endless transfer belt that extends. The intermediate transfer belt 14 is stretched around a driving roller 16 and a driven roller 17 and is circulated in a counterclockwise direction in the figure by the driving roller 16, and circulates in a counterclockwise direction indicated by arrows a, b, and c in the figure. Moving. A belt cleaner 20 is disposed in contact with the surface of the intermediate transfer belt 14. The belt cleaner 20 removes residual toner from the intermediate transfer belt 14.

  The photosensitive drum 7 rotates in the clockwise direction in the figure. First, by applying charge from the charging roller 9, the peripheral surface of the photosensitive drum 7 is uniformly charged and initialized. Next, an electrostatic latent image is formed on the peripheral surface of the photosensitive drum 7 by optical writing from the optical writing head 10 based on the print information.

  The electrostatic latent image is converted into a toner image (development) by the toner stored in the toner storage chamber 90 by the developing process by the developing roller 12. The toner image developed on the peripheral surface of the photosensitive drum 7 is directly transferred (primary transfer) to the belt surface of the intermediate transfer belt 14 by the primary transfer roller 15 as the photosensitive drum 7 rotates. The intermediate transfer belt 14 conveys the toner image directly transferred (primary transfer) to the belt surface to a transfer position to the paper 22 for further transfer (secondary transfer) to the paper 22.

  The belt position control mechanism 18 includes a primary transfer roller 15 made of a conductive foam sponge that presses against the lower peripheral surface of the photosensitive drum 7 via the intermediate transfer belt 14. The belt position control mechanism 18 includes three primary transfer rollers 15 corresponding to the three image forming units 6-1, 6-2, and 6-3 of magenta (M), cyan (C), and yellow (Y). Rotate and move in the same cycle around the saddle-shaped support shaft. The belt position control mechanism 18 rotates and moves one primary transfer roller 15 corresponding to the black (K) image forming unit 6-4 at a timing different from that of the three primary transfer rollers 15. 14 is separated from the photosensitive drum 7.

  That is, the belt position control mechanism 18 corresponds to the position of the intermediate transfer belt 14 in the full color mode (all four primary transfer rollers 15 are in contact with the intermediate transfer belt 14) and the monochrome mode (image forming unit 6-4). Only the primary transfer roller 15 is in contact with the intermediate transfer belt 14) and all non-transfer modes (all four primary transfer rollers 15 are separated from the intermediate transfer belt 14).

  The paper feed unit 4 includes two paper feed cassettes 21 arranged in two upper and lower stages. A large number of cut sheets 22 are accommodated in one or both of the sheet feed cassettes 21 of the sheet feed unit 4. Near the paper feed opening (right side in the figure) of the two paper feed cassettes 21, a paper feed roller 23, a feed roller 25, a separating roller 26, and a standby conveyance roller pair 27 are arranged, respectively. The sheet 22 is unloaded from the sheet feeding cassette 21 by one rotation of the sheet feeding roller 23, and is fed to the standby conveying roller pair 27 through the feeding roller 25 and the separating roller 26.

  A secondary transfer roller 30 that is in pressure contact with the driven roller 17 via the intermediate transfer belt 14 is disposed in the paper conveyance direction (vertical upward direction in the drawing) of the standby conveyance roller pair 27. The intermediate transfer belt 14, the driven roller 17, and the secondary transfer roller 30 form a secondary transfer portion to the paper 22.

  A fixing unit 5 composed of a belt-type heat fixing unit is disposed downstream (upward in the drawing) of the secondary transfer unit. On the further downstream side of the fixing unit 5, a pair of discharge rollers 31 that discharges the fixed sheet from the fixing unit 5 and a pair of discharge rollers that discharge the discharged sheet to a discharge tray 32 formed on the upper surface of the apparatus. 33 is arranged.

  The duplex printing conveyance unit 3 includes a return path that branches in the right lateral direction in the drawing from an intermediate conveyance path between the carry-out roller pair 31 and the paper discharge roller pair 33. This return path includes a start return path 34a, an intermediate return path 34b that bends downward, a terminal return path 34c that bends in the left lateral direction and finally reverses the return sheet, and four sets arranged in the middle of these return paths. A pair of return rollers 35a, 35b, 35c, and 35d is provided. The exit of the end return path 34 c communicates with a conveyance path to the pair of standby conveyance rollers 27 corresponding to the sheet feeding cassette 21 below the sheet feeding unit 4.

  The image forming apparatus 1 shown in FIG. 1 is a system that secondarily transfers the toner image primarily transferred to the intermediate transfer belt 14 to the paper 22 via the intermediate transfer belt 14, but is not limited thereto. A system in which a toner image is directly transferred to the paper 22 may be used.

  FIG. 2 is a perspective view showing the external structure of the image forming unit 6 according to the present embodiment. The exterior frame 40 configures the upper area of the image forming unit 6 as the toner storage chamber 90 described above, and also includes the photosensitive drum 7, the cleaner 8, the charging roller 9, the developing roller 12, and the toner supply roller shown in FIG. The developing device 11 including 13 is accommodated integrally. The image forming unit 6 can be replaced by being pulled out from the main body of the image forming apparatus 1 in the direction of arrow X.

  A replenishing port 41 for replenishing toner into the toner storage chamber 90 is provided at the top of the exterior frame 40. Further, most of the side surface 91 on the drawer side of the exterior frame 40 is formed as a flat area 91a, and the image forming unit 6 is inserted into the side surface 91 on the drawer side when the image forming unit 6 is inserted and removed. A handle 42 for gripping is provided so as to protrude toward the drawer side from the planar area 91a. Further, on the side surface 91 on the drawer side, a transport pipe 43 for collecting residual toner is disposed so as to be partially pulled out from the exterior frame 40 and protrude from the flat area 91a to the drawer side. The drawn-out portion of the transport pipe 43 is covered with a cover 44 for protecting the transport pipe 43.

  FIG. 3 is a side view showing the external structure of the image forming unit 6 according to the present embodiment. The parts corresponding to those in FIG. The exterior frame 40 includes an upper toner hopper 50 and a lower toner hopper 51. The upper toner hopper 50 is mainly configured as a toner storage chamber 90, and toner (or binder toner) and an agitator 60 are stored in the upper toner hopper 50. In the lower toner hopper 51, the photosensitive drum 7, the cleaner 8, the charging roller 9, the developing roller 12, and the toner supply roller 13 shown in FIG. Inside the conveyance pipe 43, a conveyance screw 45 made of a coil spring or the like that conveys residual toner is disposed.

  FIG. 4 is a sectional view showing the structure of the image forming unit 6 according to the present embodiment. Parts corresponding to those in FIGS. 1 to 3 are denoted by the same reference numerals and description thereof is omitted. The agitator 60 is rotated by a driving unit (not shown) to supply the toner to the lower toner hopper 51 by a predetermined amount while stirring the toner stored in the upper toner hopper 50, that is, the toner storage chamber 90. The agitating member 61 is disposed below the agitator 60 and includes a coil spring 62, and agitates the toner supplied from the upper toner hopper 50 by rotating. Below the agitating member 61, a toner supply roller 13 is disposed, and the developing roller 12 is disposed on the lower left side of the drawing with the toner supply roller 13 in contact with the peripheral surface. The doctor blade 63 disposed on the top of the developing roller 12 is in contact with the developing roller 12 to regulate the toner layer supplied onto the developing roller 12 to a certain thickness. A photosensitive drum 7 is disposed on the left side of the developing roller 12 in the drawing with the peripheral surface in contact therewith.

  The cleaning blade 64 is disposed on the left side of the photosensitive drum 7 as viewed in the drawing, and removes residual toner remaining on the peripheral surface of the photosensitive drum 7. The removed residual toner is scraped off into the cleaner 8 provided on the left side of the photosensitive drum 7, that is, the lowermost left side of the exterior frame 40 as viewed in the drawing. The conveying screw 65 rotates to sequentially convey the residual toner from the rear end portion to the front end portion of the image forming unit 6, and is further conveyed by the conveying screw 45 provided inside the conveying pipe 43. Then, the toner is transported to the waste toner collecting bag 68 housed in the upper part of the upper toner hopper 50. That is, the transfer pipe 43 is removed from the photosensitive drum 7, and the residual toner scraped off into the cleaner 8 at the bottom left side of the exterior frame 40 is positioned at the upper right side of the exterior frame 40 when viewed from the cleaner 8. It is provided as a transport path for transporting toward the storage chamber 90.

  One end (toner upstream end portion) of the transport pipe 43 is fitted into an outlet 92 provided on the pull-out side surface 91, and the other end (toner downstream end portion) is similarly connected to the pull-out side surface 91. It is arranged so as to be inserted into the upper toner hopper 50 through the provided insertion port 93. That is, the other end of the transport pipe 43 is connected to the waste toner storage pipe 67 in the upper toner hopper 50. The conveyance screw 45 built in the conveyance pipe 43 is an extension of the conveyance screw 65, and residual toner conveyed from the cleaner 8 by the conveyance screw 65 is used as a waste toner collection bag in the upper toner hopper 50. To 68. By disposing the other end of the transport pipe 43 so as to be located on the rightmost side of the upper portion of the upper toner hopper 50, the transport pipe 43 for transporting residual toner has a predetermined curvature so that the bending angle becomes an obtuse angle. It becomes possible to make the shape bent so as to have the radius R. That is, an extension line of a region of the transport pipe 43 extending to the end surface of the front end portion of the exterior frame 40 (the drawing surface of the image forming unit 6) and the other end of the transport pipe 43 are located above the upper toner hopper 50. An angle formed by the insertion tangent of the inserted portion is a predetermined oblique angle. In other words, the conveying pipe 43 extends in an inclined manner with respect to a plane formed by the end surface of the front end portion of the exterior frame 40 (the drawing surface of the image forming unit 6). Similarly, one end side of the transport pipe 43 has a predetermined oblique corner. In other words, the conveyance pipe 43 extends at an angle with respect to a plane formed by the end surface of the front end portion of the exterior frame 40 (the drawing surface of the image forming unit 6) instead of being vertical. Yes. The handle 42 for inserting and removing the image forming unit 6 and the transport pipe 43 for transporting residual toner to the waste toner collecting bag 68 are arranged so as not to interfere with each other on the side surface 91 on the drawer side. Yes.

  In addition, the conveyance pipe 43 in the region from the outlet 92 to the insertion port 93 has a predetermined curvature radius R so that the bent shape becomes an obtuse angle when viewed in plan from the pulling direction. Is formed. In other words, at least a part of the transport pipe 43 is routed outside the exterior frame 40 on the side surface side of the exterior frame 40, and the routing shape of the region routed outside this is viewed in plan view from the pull-out direction. In addition, it is formed in a shape having a predetermined radius of curvature R so that the bending angle becomes an obtuse angle so as not to interfere with other components.

  If only the upper toner hopper 50 (so-called toner cartridge) is detachably attached to replace or replenish the toner, the handle 42 must be provided at least at a location other than the upper toner hopper 50 on the side surface 91 on the drawer side. In the case of such a separation structure, the transport pipe 43 cannot be inserted into the upper toner hopper 50 on the side surface 91 on the drawer side.

  In contrast, in the present embodiment, the upper toner hopper 50 and the lower toner hopper 51 are integrated, and the image forming unit 6 is inserted into and removed from the image forming apparatus 1 without being separated. In addition, the image forming unit 6 can be inserted into the upper toner hopper 50 on the side surface 91 on the drawer side. Therefore, in this embodiment, by providing the conveyance pipe 43 between the outlet 92 and the insertion port 93 on the side surface 91 on the drawer side, it becomes possible to make the bending angle of the conveyance pipe 43 gentle. The conveyance path can be shortened, and further, the bent portion of the conveyance pipe 43 can be reduced (eliminated) as much as possible, so that the conveyance can be performed quickly and without resistance as much as possible. As a result, even when a binder toner having a large particle size is transported, it can be transported quickly and without resistance. Further, the transport pipe 43 is formed so that the direction in which the residual toner is transported does not face downward. In other words, the transport pipe 43 is formed so that the direction in which the residual toner is transported is upward.

  5A and 5B are schematic views showing the shape of the transport pipe 43 according to the present embodiment. In the present embodiment, as shown in FIG. 5 (a), in the transport pipe 43, the attachment portion 70 pulled up from the outlet 92 has a shape having a predetermined radius of curvature R so that the bending angle becomes an obtuse angle. It is composed. Further, as shown in FIG. 5B, the attachment portion 71 of the transport pipe 43 inserted into the insertion port 93 is configured to have a shape having a predetermined curvature radius R so that the bending angle becomes an obtuse angle. doing.

  Further, as shown in FIG. 5B, when the conveyance pipe 43 in the region 72 from the outlet 92 to the insertion port 93 is avoided from interfering with the handle 42, the bending angle is obtuse. Are configured to have a predetermined radius of curvature R. For this reason, even when a binder toner having a large particle size is transported, it can be transported as quickly as possible without resistance.

  FIG. 6 is a schematic diagram for explaining a collection path for residual toner in the image forming apparatus 1 according to the present embodiment. Residual toner on the photosensitive drum 7 is scraped off into the cleaner 8 by the cleaning blade 64, and the bent portion is reduced as much as possible by the conveying screw 65 in the cleaner 8 and the conveying screw 45 rotating in the conveying pipe 43 ( The toner is transported to the uppermost portion of the upper toner hopper 50 via the transport pipe 43 and is collected in the waste toner collection bag 68 via the transport screw 66 in the waste toner storage pipe 67 disposed in the upper toner hopper 50. Is done.

  According to the embodiment described above, the residual toner in the cleaner 8 of the image forming unit 6 is transferred to the upper toner via the transport pipe 43 arranged so as to be drawn around the side surface 91 on the drawer side of the exterior frame 40. Since the waste toner is collected in the waste toner collection bag 68 in the hopper 50, the transport path of the residual toner can be shortened, and the risk of occurrence of clogging or clumping of the residual toner in the transport pipe 43 can be reduced. As a result, the conveyance screw 45 is prevented from being damaged, and even a toner having a large particle diameter such as a binder toner can be stably conveyed.

  Further, according to the above-described embodiment, the mounting portion 70 pulled up from the outlet 92 has a shape having a predetermined radius of curvature R so that the bending angle becomes an obtuse angle, and the mounting portion 71 of the transport pipe 43 is bent. Since it has a shape having a predetermined radius of curvature R so that the angle becomes obtuse, it is possible to prevent clogging or clumping of residual toner during conveyance in the middle of the conveyance path inside the conveyance pipe 43. As a result, the rotation of the conveying screw 45 provided inside the conveying pipe 43 can be smoothly and stably driven, and the conveying screw 45 can be prevented from being damaged. However, it can be stably conveyed. Further, when the conveyance destination space is filled with residual toner, the expansion and contraction of the conveyance screw 45 due to the pushing back of the tip of the conveyance screw 45 is not hindered, and the conveyance screw 45 is rigid so as not to be pushed back. It is also possible to have

  Further, according to the above-described embodiment, it is possible to stably convey a toner having a large particle diameter such as a binder toner without increasing the diameter of the conveying pipe 43.

As mentioned above, although several embodiment of this invention was described, this invention is not limited to these, The invention described in the claim, and its equal range are included.
Below, the invention described in the claims of the present application is appended.

(Appendix 1)
The invention according to appendix 1 includes a toner storage chamber in which toner is stored, a photosensitive drum on which an electrostatic latent image is formed and toner is supplied from the toner storage chamber, and a toner drum that is removed from the photosensitive drum. A transport pipe for transporting the residual toner to the toner storage chamber, and an exterior frame that forms the toner storage chamber and stores the photosensitive drum, and at least a part of the transport pipe is the exterior The outer side of the exterior frame is routed on the side surface side of the frame, and the shape of the connecting portion protruding from the side surface of the exterior frame is formed so as to be inclined with respect to the plane formed by the side surface. An image forming unit characterized by the above.

(Appendix 2)
The image forming apparatus according to appendix 1, wherein the transport pipe is extended so that at least a part of the transport pipe does not interfere with other components on the side surface in the pull-out direction. Is a unit.

(Appendix 3)
The invention according to appendix 3 is characterized in that the at least part of the transport pipe is formed in a curved shape or a shape without a bending point when viewed in plan from the pull-out direction of the exterior frame. The image forming unit according to 1 or 2.

(Appendix 4)
The invention according to appendix 4 is the image forming unit according to any one of appendices 1 to 3, wherein at least a part of the transport pipe is covered with a predetermined cover.

(Appendix 5)
The invention according to attachment 5 is an image forming apparatus detachably including an image forming unit for developing a toner image, wherein the image forming unit forms a toner storage chamber in which toner is stored and an electrostatic latent image is formed. A photosensitive drum to which toner is supplied from the toner storage chamber; a transport pipe for transporting residual toner removed from the photosensitive drum to the toner storage chamber; and the toner storage chamber. And an exterior frame that accommodates the photosensitive drum, and at least a part of the transport pipe is routed outside the exterior frame on the side surface side of the exterior frame, and from the side surface of the exterior frame. In the image forming apparatus, the protruding connecting portion is formed so as to be inclined with respect to a plane formed by the side surface.

DESCRIPTION OF SYMBOLS 1 Image forming apparatus 2 Image forming part 3 Duplex printing conveyance unit 4 Paper feed part 5 Fixing part 6 (6-1, 6-2, 6-3, 6-4) Image forming unit 7 Photosensitive drum 8 Cleaner 9 Charging Roller 10 Optical writing head 11 Developing device 12 Developing roller 13 Toner supply roller 14 Intermediate transfer belt 15 Primary transfer roller 16 Driving roller 17 Driven roller 18 Belt position control mechanism 20 Belt cleaner 21 Paper feed cassette 22 Paper (printed medium)
23 Feeding roller 25 Feeding roller 26 Rolling roller 27 Standby transport roller pair 30 Secondary transfer roller 31 Unloading roller pair 32 Paper discharge tray 33 Paper discharge roller pair 34a Start return path 34b Intermediate return path 34c End return path 40 Exterior frame 41 Supply port 42 Handle 43 Conveying pipe 44 Cover 45 Conveying screw 50 Upper toner hopper 51 Lower toner hopper 60 Agitator 61 Stirring member 62 Coil spring 63 Doctor blade 64 Cleaning blade 65 Conveying screw 66 Conveying screw 67 Waste toner containing pipe 68 Waste toner collecting bag 70 , 71 Mounting portion 72 Area 90 Toner storage chamber 91 Side surface 91a Planar area 92 Outlet 93 Insertion slot

Claims (5)

A toner storage chamber for storing toner;
A photosensitive drum on which an electrostatic latent image is formed and toner is supplied from the toner storage chamber;
A transport pipe for transporting residual toner removed from the photosensitive drum to the toner storage chamber;
An exterior frame that constitutes the toner accommodating chamber and accommodates the photosensitive drum;
With
At least a part of the transport pipe is routed outside the exterior frame on the side surface side of the exterior frame, and the shape of the connecting portion protruding from the side surface of the exterior frame is relative to the plane formed by the side surface. The image forming unit is formed so as to be inclined.   2. The image forming unit according to claim 1, wherein the transport pipe is extended so that at least a part of the transport pipe does not interfere with other components on a side surface in the pull-out direction. The transport pipe is formed in a curved shape or a shape without a bending point when the at least part is viewed in plan from the pull-out direction of the exterior frame.
The image forming unit according to claim 1, wherein:   The image forming unit according to claim 1, wherein at least a part of the transport pipe is covered with a predetermined cover. An image forming apparatus detachably equipped with an image forming unit for developing a toner image,
The image forming unit includes:
A toner storage chamber for storing toner;
A photosensitive drum on which an electrostatic latent image is formed and toner is supplied from the toner storage chamber;
A transport pipe for transporting residual toner removed from the photosensitive drum to the toner storage chamber;
An exterior frame that constitutes the toner accommodating chamber and accommodates the photosensitive drum;
With
At least a part of the transport pipe is routed outside the exterior frame on the side surface side of the exterior frame, and the shape of the connecting portion protruding from the side surface of the exterior frame is relative to the plane formed by the side surface. Formed to be inclined,
An image forming apparatus.

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