JP5704036B2 - Image forming apparatus - Google Patents

Description

  According to the present invention, a toner cartridge containing toner or an image forming cartridge including a toner cartridge is configured to be detachable, and recording is performed in an electrophotographic system using an endless belt that is laid between a plurality of rollers and driven to rotate. The present invention relates to an image forming apparatus that forms an image on a medium.

  As an image forming apparatus using a toner cartridge containing toner and an endless belt that is laid and rotated between a plurality of rollers, for example, a sheet as a recording medium is conveyed by the endless belt onto the sheet. An image forming apparatus that transfers a toner image is known. In this type of image forming apparatus, a toner cartridge containing toner is detachable, and a drum cartridge that forms a toner image to be transferred onto a sheet using the toner on the surface of a photosensitive drum as an electrostatic latent image carrier. It has been proposed that the (image forming cartridge) is also detachable from the endless belt (see, for example, Patent Document 1).

In addition, it has been proposed that a drum cartridge (image forming cartridge) including a toner cartridge be detachable integrally with an endless belt.
In the former image forming apparatus, in order to prevent toner deterioration, the toner cartridge may be individually packaged in a moisture-proof pack, and the drum cartridge may be shipped mounted on an apparatus main body having an endless belt. By doing so, deterioration of the toner due to moisture can be prevented, and only the toner cartridge can be separately packed, so that the packaging size of the entire image forming apparatus can be suppressed and packaging materials can be saved.

  Further, in the latter image forming apparatus, since the toner cartridge and the drum cartridge are configured so as not to be separated (integrated), the packaging size is slightly larger, but they are separately packaged as a single unit. By doing so, it is possible to prevent toner deterioration.

  On the other hand, the endless belt used in the image forming apparatus is not limited to the so-called transfer conveyance belt as described above, and is used by being laid between a plurality of rollers in a state where a certain amount of tension is applied. It is desirable not to apply tension in order to prevent deformation. Therefore, a tension release member is fitted into a mechanism that applies tension to the endless belt so as not to apply tension to the endless belt, and the tension release member is removed after installation of the image forming apparatus to apply tension to the endless belt. (For example, refer to Patent Documents 2 and 3).

JP 2010-102306 A JP 2009-47869 A Japanese Patent Laid-Open No. 7-129031

  However, the operation of pulling out the tension releasing member as described in Patent Documents 2 and 3 is troublesome for a general user and sometimes forgets to remove the tension releasing member. On the other hand, at least the climatic conditions where it is desirable to separately package the toner cartridge and the climatic conditions where it is desirable not to apply tension to the endless belt at the time of shipment are both in a high temperature and high humidity environment. Almost matches.

  Accordingly, the present invention provides an image forming apparatus capable of keeping tension on an endless belt for image formation at the time of shipment, and automatically when the toner cartridge is mounted when the image forming apparatus is installed. It was made for the purpose of giving tension.

  The image forming apparatus of the present invention made to achieve the above object includes a toner cartridge containing toner, an endless belt that is laid between a plurality of rollers and is driven to rotate, and the toner cartridge is detachable. An image forming unit configured to form an image of a toner contained in the toner cartridge on the recording medium using the endless belt and at least one of the rollers is urged in a direction in which tension is applied to the endless belt. An urging member; a relaxed position that supports the at least one roller in a position that does not apply tension to the endless belt against the urging force of the urging member; and an application of the at least one roller by the urging member. A stopper member movably provided at a tension position that does not hinder the force, and the stopper member is disposed at the relaxed position. If the toner cartridge is mounted on the image forming unit, the movement of the toner cartridge does not move and remains in the relaxed position. When the toner cartridge is mounted on the image forming unit, the tension is released from the relaxed position. It is characterized by moving to a position.

  In the image forming apparatus of the present invention configured as described above, at least one of the rollers is urged by the urging member of the endless belt that is installed between the plurality of rollers and is used for image formation in the image forming unit. Is given tension. The image forming unit is configured to be detachable from a toner cartridge containing toner, and forms an image of the toner contained in the toner cartridge on a recording medium using the endless belt.

  Here, the stopper member is provided to be movable between the following relaxed position and tension position. That is, when the stopper member is disposed at the relaxed position, the stopper member supports the at least one roller at a position where no tension is applied to the endless belt against the urging force of the urging member. For this reason, when the stopper member is disposed at the relaxed position, no tension is applied to the endless belt. On the other hand, when the stopper member is disposed at the tension position, the stopper member does not hinder the urging of the at least one roller by the urging member. For this reason, when the stopper member is disposed at the tension position, it is possible to form an image by the image forming unit by applying tension to the endless belt.

  Further, when the stopper member is disposed at the relaxed position, the toner cartridge moves from the relaxed position to the tension position when the toner cartridge is mounted on the image forming unit, and the toner cartridge is mounted on the image forming unit. The movement is not performed until it is done. For this reason, if the stopper member is disposed at the relaxed position at the time of shipment of the image forming apparatus, the stopper member does not move from the relaxed position until the toner cartridge is mounted on the image forming unit, and the endless belt is not moved therebetween. It can suppress that tension is given. When the toner cartridge is mounted on the image forming unit when the image forming apparatus is installed, the stopper member moves from the relaxed position to the tensioned position, and tension is applied to the endless belt. For this reason, in the image forming apparatus of the present invention, even if the user is not conscious of the endless belt, if the toner cartridge is installed at the time of installation, the tension is automatically applied to the endless belt using the operation as a trigger. it can.

  The image forming unit includes an electrostatic latent image carrier on which an electrostatic latent image is formed, and is configured to be detachable from the endless belt, and the toner cartridge is configured to be detachable. An image forming cartridge that forms a toner image corresponding to the electrostatic latent image on a surface of the electrostatic latent image carrier using toner contained in the toner cartridge mounted on the toner cartridge; The toner image formed on the surface of the electrostatic latent image carrier is transferred to a recording medium, and the stopper member is disposed at the relaxed position, and the toner cartridge is not mounted. When the image forming cartridge is attached to the image forming portion, the toner cartridge remains in the relaxed position without moving and is disposed in the relaxed position. Or it may be moved to the tensioned position from the relaxed position when the mounted imaging cartridge is mounted to the image forming unit.

  In this case, when the electrostatic latent image is formed on the surface of the electrostatic latent image carrier, the image forming cartridge uses the toner contained in the toner cartridge attached to the electrostatic latent image carrier, A toner image corresponding to the electrostatic latent image is formed on the surface. Then, the endless belt forms an image by transferring the toner image formed on the surface of the electrostatic latent image carrier onto a recording medium. In this transfer method, the endless belt may directly transfer the toner image to the recording medium while conveying the recording medium to the portion facing the electrostatic latent image carrier, and the endless belt may transfer the toner. The image may be once transferred to itself and the toner image may be further transferred to a recording medium.

  In an image forming apparatus including such an image forming unit, a toner cartridge may be individually packaged in a moisture-proof pack, and the image forming cartridge may be mounted on an apparatus main body including an endless belt before shipment. By doing so, deterioration of the toner due to moisture can be prevented, and only the toner cartridge can be separately packed, so that the packing size of the entire image forming apparatus can be suppressed, and packaging materials can be saved. In the present invention, the stopper member does not move to the tension position even when an image forming cartridge without a toner cartridge is attached to the endless belt at the time of shipment. Then, when the image forming cartridge having the toner cartridge mounted thereon is mounted on the endless belt when the image forming apparatus is installed, the stopper member moves to the tension position as described above to apply tension to the endless belt. it can. Therefore, the packing method as described above can also be favorably employed.

  In this case, the stopper member is provided so as to come into contact with the toner cartridge mounted on the image forming cartridge. When the stopper member is disposed at the relaxed position, the toner cartridge is not mounted. When the image forming cartridge is mounted on the image forming unit, the toner cartridge is not pressed and stays in the relaxed position without being moved, and when the toner cartridge is disposed in the relaxed position, When the mounted image forming cartridge is mounted on the image forming unit, the toner cartridge may be pressed to move from the relaxed position to the tensioned position.

  That is, in this case, when the image forming cartridge with the toner cartridge attached is attached to the endless belt, the stopper member moves from the relaxed position to the tensioned position by the pressing force applied from the toner cartridge. Therefore, the structure of the apparatus can be further simplified by using such a mechanical pressing force.

  Further, as the plurality of rollers, a driving roller that rotationally drives the endless belt, a driven roller that rotates following the endless belt and stretches the endless belt at a contact position with the electrostatic latent image carrier, The at least one roller may be the driven roller. Thus, when the biasing member and the stopper member are provided for the driven roller, the configuration of the apparatus can be further simplified as compared with the case where the biasing member and the stopper member are provided for the drive roller.

  In this case, the image forming unit includes a plurality of the image forming cartridges configured to be detachable with respect to the endless belt, and the stopper member is closest to the driven roller among the plurality of image forming cartridges. The specific image formation in which the toner cartridge is not attached when the toner cartridge is provided in contact with the toner cartridge attached to the specific image forming cartridge attached to the toner cartridge and disposed in the relaxed position. When the cartridge is mounted on the image forming unit, the toner cartridge is mounted when the toner cartridge is not pressed and does not move and stays in the relaxed position. When the specific image forming cartridge is mounted on the image forming unit, the toner cartridge Been pressed may be configured to move to the tensioning position from the relaxed position.

  That is, in this case, the stopper member closest to the driven roller among the plurality of image forming cartridges is loosened by the pressing force applied from the toner cartridge when the toner cartridge is attached to the image forming portion. Move from position to tension position. Since the urging member and the stopper member are provided with respect to the driven roller, the mechanism for transmitting the pressing force to the stopper member can be greatly simplified because the transmission path is shortened. Therefore, in this case, the configuration of the apparatus can be further simplified.

  The image forming unit includes the toner cartridge, includes an electrostatic latent image carrier on which an electrostatic latent image is formed, is configured to be detachable from the endless belt, and is accommodated in the toner cartridge. An image forming cartridge that forms a toner image corresponding to the electrostatic latent image on the surface of the electrostatic latent image carrier using the toner, and the endless belt is disposed on the surface of the electrostatic latent image carrier. When the formed toner image is transferred to a recording medium, and the stopper member is disposed at the relaxed position, and the image forming cartridge including the toner cartridge is not attached to the image forming unit. The image forming cartridge including the toner cartridge is mounted on the image forming portion when the ink stays in the relaxed position without moving and is disposed in the relaxed position. Or it may be moved to the tensioned position from the relaxed position when it is.

  In an image forming apparatus including such an image forming unit, an image forming cartridge including a toner cartridge is shipped in a state of being packed in a moisture-proof pack as an integral unit, thereby preventing deterioration of toner due to moisture. . In addition, since the image forming cartridge including the toner cartridge is not attached to the endless belt, the stopper member does not move to the tension position. When the image forming apparatus including the toner cartridge is attached to the endless belt when the image forming apparatus is installed, the stopper member can be moved to the tension position as described above to apply tension to the endless belt. . Therefore, the image forming operation is not started without applying tension to the endless belt.

  Further, as the plurality of rollers, a driving roller that rotationally drives the endless belt, a driven roller that rotates following the endless belt and stretches the endless belt at a contact position with the electrostatic latent image carrier, A tension roller that applies tension to the endless belt, and the at least one roller may be the tension roller. As described above, when the biasing member and the stopper member are provided for the tension roller provided for the purpose of applying tension to the endless belt, the biasing member and the stopper member are provided for the driving roller or the driven roller. In comparison, the configuration of the apparatus can be further simplified.

1 is a central sectional view schematically showing a configuration of an image forming apparatus according to an embodiment. FIG. 6 is an explanatory diagram illustrating a cover opening operation of the image forming apparatus. 2 is a side view illustrating a configuration of a main part of a belt unit of the image forming apparatus. FIG. FIG. 4 is a side view and a cross-sectional view illustrating a configuration of a main part of the belt unit when a drum cartridge having a developing cartridge is mounted. FIG. 6 is a side view and a cross-sectional view illustrating a configuration of a main part of the belt unit when a drum cartridge without a developing cartridge is mounted. FIG. 3 is a perspective view illustrating a configuration of the developing cartridge. FIG. 6 is a perspective view showing the vicinity of a drum cartridge in the state of FIG. 5. FIG. 6 is a central sectional view schematically showing a configuration of an image forming apparatus according to another embodiment.

[Schematic configuration of image forming apparatus]
Next, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a central sectional view schematically showing a configuration of an image forming apparatus 1 according to the present embodiment. In the following description, the left side in FIG.

  As shown in FIG. 1, an image forming unit 2 that forms an image on a sheet or an OHP sheet (hereinafter referred to as sheet P) as an example of a recording medium includes four process cartridges 3K, 3Y, 3M, and 3C, and an exposure unit. 4, a fixing device 5, a belt unit 10, and the like. In the present embodiment, the image forming unit 2 includes four types of four process cartridges 3K, 3Y, 3M, and 3C corresponding to toners (developers) of four colors of black, yellow, magenta, and cyan. A direct tandem method in which a toner image (developer image) is superimposed on the paper P to form a color image on the paper P is employed.

  Of the plurality of sheets P placed on the sheet feeding cassette 6 mounted below the image forming unit 2, the sheet P positioned at the top in the stacking direction picked up by the sheet feeding mechanism (feeder unit) 7 is After the paper dust is removed by the paper dust removing roller 8, it is conveyed to the registration roller 9. The registration roller 9 corrects the skew of the paper P and sends it to the belt unit 10 at a predetermined timing. Details of the belt unit 10 will be described later. The four process cartridges 3K and the like are arranged in series in the order of the process cartridges 3K, 3Y, 3M, and 3C from the upstream along the conveyance direction of the sheet P on the sheet conveyance surface side of the belt unit 10.

  For this reason, four types of toner images are sequentially transferred onto the paper P conveyed on the belt unit 10, and the toner images that have been transferred onto the paper P are heated by the fixing device 5 to be paper Fix to P. Then, the paper P discharged from the fixing device 5 is turned upward, and then discharged to a paper discharge tray 1A provided on the upper end surface side of the image forming apparatus 1.

  Each process cartridge 3K, 3Y, 3M, 3C includes a photosensitive drum 3A on which a toner image is carried, a charger 3E for charging the photosensitive drum 3A (see FIG. 4), and a toner on the photosensitive drum 3A. A developing cartridge 3P (an example of a toner cartridge) is supplied. Then, after the outer peripheral surface of the photosensitive drum 3A charged by the charger 3E is exposed by the exposure device 4 to form an electrostatic latent image, toner is supplied to the electrostatic latent image from the developing cartridge 3P. A toner image is carried (formed) on the surface, and the toner image is transferred to the paper P. The developing cartridge 3P contains toner therein and supplies the toner to the photosensitive drum 3A while being frictionally charged by the developing roller 3Q or the like.

  The fixing device 5 is also provided with a heating roller 5A for heating the toner to fix the toner image on the paper P, and a heating roller 5A disposed on the opposite side of the heating roller 5A across the conveyed paper P. And a pressure roller 5B that is pressed against the 5A side.

  As described above, the belt unit 10 is disposed at a position facing the photosensitive drums 3A of the four process cartridges 3K, 3Y, 3M, and 3C, and conveys the paper P. Specifically, the belt unit 10 includes a drive roller 12A and a driven roller 12B having a rotation axis parallel to the rotation axis of the photosensitive drum 3A, and a transfer conveyance belt provided between the drive roller 12A and the driven roller 12B. 12C (an example of an endless belt) or the like, and the paper P is conveyed in a state of being placed (adsorbed) on the transfer conveyance belt 12C. The driving roller 12A receives power from a motor (not shown) provided in the apparatus main body (not shown) and rotates the transfer conveyance belt 12C. The driven roller 12B is driven by the transfer conveyance belt 12C. Along with the rotation, it rotates following the drive roller 12A.

  Further, the tensioning surface of the transfer conveyance belt 12C facing the photosensitive drum 3A of each process cartridge 3K, 3Y, 3M, 3C is a planar conveyance surface for conveying the paper P in the transfer conveyance belt 12C. In this embodiment, it almost coincides with the horizontal plane. Further, a toner image carried on the photosensitive drum 3A by energizing a certain transfer current at a position of the belt unit 10 facing each photosensitive drum 3A across the semiconductive transfer conveyance belt 12C. Are respectively provided with transfer rollers 3B for transferring the toner onto the paper P.

  By the way, the above-mentioned four process cartridges 3K, 3Y, 3M, 3C and the belt unit 10 are detachably attached to the apparatus main body (main body frame) covered with the casing 1C constituting the appearance design surface. . The top cover 1F provided with the paper discharge tray 1A in the housing 1C is assembled to the housing 1C so as to be swingable (openable / closable), and the top cover 1F is moved upward as shown in FIG. By opening, the four process cartridges 3K, 3Y, 3M, and 3C can be exchanged. The process cartridges 3K, 3Y, 3M, and 3C are configured so that each photosensitive drum 3A is transferred and conveyed by a known configuration described in, for example, Japanese Unexamined Patent Application Publication Nos. 2009-162903 and 2009-162904. It is positioned and mounted at a position facing 12C.

[Details of belt unit and process cartridge]
Next, detailed configurations of the belt unit 10 and the process cartridge 3K will be described with reference to FIGS. 3 to 5 are views of the belt unit 10 or the process cartridge 3K viewed from the back side of FIG. Further, the process cartridges 3Y, 3M, and 3C are configured similarly to the process cartridge 3K.

  As shown in FIG. 3, the belt unit 10 includes a pair of left and right belt unit side frames 13 that support the drive roller 12A, the driven roller 12B, and the transfer roller 3B described above from both sides in the axial direction (hereinafter also referred to as the left-right direction). ing. Among these, the shaft 12E of the driven roller 12B disposed on the front side of the belt unit 10 is supported by the belt unit side frame 13 via the bearing portion 13A. The bearing portion 13A is configured to rotatably support the shaft 12E and to be slidable along a groove 13B formed in the belt unit side frame 13 in the front-rear direction. The compression coil spring 13C (an example of a biasing member) Is biased forward. For this reason, tension can be applied to the transfer conveyance belt 12C provided between the driving roller 12A and the driven roller 12B by the urging force of the compression coil spring 13C. The pair of left and right belt unit side frames 13 are connected to each other at each part including the handle part 13D, and are arranged at a certain interval in the left-right direction.

  Further, the belt unit side frame 13 is formed with a groove 13E connected to the front end of the groove 13B and extending in the vertical direction, and the following stopper member 14 is provided in the groove 13E. That is, the stopper member 14 has a concave portion 14B cut out from the rear slightly above the lower end portion 14A, and the groove 13E is formed by a pair of upper and lower guide pieces 13G and 13H provided on the belt unit side frame 13. In a state in which it is restricted from being detached from, it is configured to be slidable between a tension position shown in FIG. 3 (A) and a relaxation position shown in FIG. 3 (B). Further, the stopper member 14 is provided with a snap-fit 14D for suppressing the paralysis that can be bent against its own elastic force, while the rear inner wall surface of the groove 13E is a circle that can be engaged with the snap-fit 14D. An arc-shaped protrusion 13F is provided. For this reason, the stopper member 14 has the tension position shown in FIG. 3 (A) and FIG. 3 only when the force necessary for the snap fit 14D to overcome the arc-shaped protrusion 13F against its own elastic force is applied. It can slide between the relaxed positions shown in (B).

  As shown in FIG. 3A, when the stopper member 14 is disposed at a tension position where the recess 14B is connected to the groove 13B, the bearing portion 13A can also slide inside the recess 14B. In this case, the stopper member 14 does not prevent the bearing portion 13A from sliding forward due to the urging force of the compression coil spring 13C. In this case, the transfer / conveying belt 12C is given sufficient tension according to the urging force of the compression coil spring 13C. On the other hand, as shown in FIG. 3B, when the stopper member 14 is disposed at the relaxed position where the lower end portion 14A faces the bearing portion 13A, the bearing portion 13A has a front end that comes into contact with the lower end portion 14A. It cannot move forward. For this reason, the tension applied to the transfer conveyance belt 12C is suppressed. That is, the tension due to the urging force of the compression coil spring 13C is not applied to the transfer conveyance belt 12C.

  Further, the upper end surface 14 </ b> C of the stopper member 14 is fixed to the belt unit 10 by mounting the process cartridge 3 </ b> K on a main body frame (not shown) that is provided in the housing 1 </ b> C and supports the belt unit 10. When it is installed, it receives a pressing force as follows. The process cartridge 3K can be disassembled into a drum cartridge 3F (an example of an image forming cartridge) that holds the charger 3E and the photosensitive drum 3A and the developing cartridge 3P as described below.

  4A is a side view showing a state where the drum cartridge 3F with the developing cartridge 3P attached is attached to the belt unit 10, and FIG. 4B is a cross-sectional view showing the state. is there. FIG. 5A is a side view showing a state in which the drum cartridge 3F without the developing cartridge 3P is attached to the belt unit 10, and FIG. 5B shows the state. It is sectional drawing. 4B and 5B, the developing cartridge 3P is cut at a position in front of the stopper member 14, and a part of the configuration on the back side of the drawing from the cut surface is omitted. Yes.

  As shown in FIGS. 4B and 5B, the drum cartridge 3F includes a mounting portion 3G that is recessed in a boat shape to which the developing cartridge 3P is mounted, and the developing cartridge 3P is disposed inside the mounting portion 3G. Is installed. Further, as shown in the perspective view of FIG. 6, the rotating shaft 3R of the developing roller 3Q protrudes from the left and right side surfaces of the developing cartridge 3P. As shown in FIGS. 4A and 5A, the drum cartridge 3F has a U-shaped notch 3H formed toward the photosensitive drum 3A, and when the developing cartridge 3P is mounted, The rotating shaft 3R is fitted into the notch 3H. Further, a rectangular hole 3J is formed in the lower surface of the mounting portion 3G over the entire width direction of the mounting portion 3G (see FIG. 7), and when the developing cartridge 3P is mounted, one of the developing cartridge 3P is formed. The part fits into the hole 3J. The developing cartridge 3P is configured such that, as described in, for example, Japanese Patent Application Laid-Open No. 2009-162905, the developing roller 3Q is a photosensitive drum in a state where the rotating shaft 3R is fitted in the notch 3H of the drum cartridge 3F. Although it is elastically biased downward so as to contact 3A, the biasing force is sufficiently larger than the force required for the snap fit 14D provided on the stopper member 14 to get over the protrusion 13F.

  Here, when the drum cartridge 3F of the process cartridge 3K is attached to the belt unit 10 without the developing cartridge 3P attached, the upper end surface 14C of the stopper member 14 is shown in FIGS. As shown, it can pass through the hole 3J. Therefore, the stopper member 14 is disposed at the relaxed position by sandwiching the lower end portion 14A between the bearing portion 13A and the groove 13B by the urging force of the compression coil spring 13C, and only the drum cartridge 3F is attached to the belt unit 10. If attached, the stopper member 14 is held at the relaxed position when the upper end surface 14C passes through the hole 3J. In this state, it is possible to suppress tension from being applied to the transfer conveyance belt 12C.

  On the other hand, if the drum cartridge 3F of the process cartridge 3K is attached to the belt unit 10 with the developing cartridge 3P attached, the upper end surface 14C is pressed against the developing cartridge 3P as shown in FIG. The member 14 moves to the tension position, and the bearing portion 13A can slide inside the recess 14B. In this state, a sufficient tension is applied to the transfer conveyance belt 12C for image formation.

[Effects of this embodiment and its modifications]
The image forming apparatus 1 of the present embodiment configured as described above is shipped with the developing cartridge 3P removed from the process cartridges 3K, 3Y, 3M, and 3C, and only the drum cartridge 3F being mounted on the belt unit 10. (See FIG. 5). At this time, the stopper member 14 is placed in the relaxed position, and tension can be prevented from being applied to the transfer / conveying belt 12C in the distribution process including during transportation. Accordingly, it is possible to satisfactorily suppress the occurrence of deformation such as creep in the transfer conveyance belt 12C before the image forming apparatus 1 is installed. Further, the removed developing cartridges 3P are separately packed in a moisture-proof pack 99 and attached to the main body of the image forming apparatus 1 as indicated by phantom lines in FIG. For this reason, it is possible to satisfactorily suppress deterioration of the toner due to moisture.

  Next, when installing the image forming apparatus 1, the user opens the moisture-proof pack 99, attaches the developing cartridge 3 </ b> P to each of the process cartridges 3 </ b> K, 3 </ b> Y, 3 </ b> M, and 3 </ b> C, and remounts the belt unit 10. Then, by mounting the process cartridge 3K with the developing cartridge 3P mounted, as described above, the stopper member 14 moves from the relaxed position to the tension position, and sufficient tension is applied to the transfer conveyance belt 12C. (See FIG. 4).

  For this reason, even if the user is not conscious of the transfer conveyance belt 12C, if the developing cartridge 3P is mounted as described above, it is possible to automatically apply tension to the transfer conveyance belt 12C using the operation as a trigger. When the bearing portion 13A is fitted into the recess 14B, the fitting is maintained by the urging force of the compression coil spring 13C. For this reason, even when the process cartridge 3K is removed after the fitting, the stopper member 14 remains in the tension position, and the tension of the transfer conveyance belt 12C is maintained. For example, even if the process cartridge 3K is temporarily removed for jam processing or toner replenishment, the stopper member 14 remains in the tension position and the tension of the transfer conveyance belt 12C is maintained.

  The present invention is not limited to the above-described embodiment, and can be implemented in various forms without departing from the gist of the present invention. For example, as the belt unit 10, as shown in FIG. 8, a configuration in which a tension roller 12 </ b> S is provided in addition to the driving roller 12 </ b> A and the driven roller 12 </ b> B, and a transfer conveyance belt 12 </ b> C is installed between the three members. be able to. In this case, the tension roller 12S is biased by the compression coil spring 13S in the direction opposite to the process cartridges 3K, 3Y, 3M, 3C (downward), thereby applying tension to the transfer / conveying belt 12C. Also in this case, it is possible to provide a stopper member that switches whether or not to apply the tension, depending on whether or not the process cartridge 3K with the developing cartridge 3P is mounted.

  In this case, since the tension roller 12S is a roller provided for the purpose of applying tension to the transfer / conveying belt 12C, the configuration of the stopper member can be easily simplified. Also in the above-described embodiment, since the stopper member 14 is in the immediate vicinity of the mounting position of the process cartridge 3K, the pressing force applied from the developing cartridge 3P can be directly transmitted to the stopper member 14, and the configuration can be simplified easily. be able to.

  Further, as a mechanism for moving the stopper member depending on whether or not the process cartridge 3K in which the developing cartridge 3P is mounted is mounted, another link mechanism other than the above may be used. May be used. That is, it is possible to electrically detect whether or not the developing cartridge 3P is attached to the attached process cartridge 3K with a sensor or a switch, and move the stopper member with an electric actuator. However, in the said embodiment, the structure of an apparatus can be further simplified by utilizing mechanical pressing force. In addition, since the compression coil spring 13C and the stopper member 14 are provided for the driven roller 12B rather than the drive roller 12A directly driven by a motor or gear, the configuration of the apparatus can be further simplified.

  Furthermore, the present invention can also be applied to an image forming apparatus in which the drum cartridge 3F and the developing cartridge 3P are integrated. However, in this case, the process cartridge in which the drum cartridge 3F and the developing cartridge 3P are integrated needs to be separately packed as described above, but in this embodiment, only the developing cartridge 3P needs to be separately packed. The packaging size of the forming apparatus 1 as a whole can be suppressed, and packaging materials can be saved. The present invention can also be applied to an image forming apparatus of a type in which a toner cartridge as a toner container can be removed from the developing cartridge 3P with the developing roller 3Q remaining. In that case, only the toner cartridge may be separately packed. Needless to say, the present invention can also be applied to a monochrome type image forming apparatus and an image forming apparatus using an intermediate transfer belt as an endless belt.

DESCRIPTION OF SYMBOLS 1 ... Image forming apparatus 2 ... Image forming part 3A ... Photosensitive drum 3F ... Drum cartridge 3G ... Mounting part 3J ... Hole part 3K, 3Y, 3M, 3C ... Process cartridge 3P ... Developing cartridge 3Q ... Developing roller 4 ... Exposure device 10 ... belt unit 12A ... drive roller 12B ... driven roller 12C ... transfer conveying belt 12S ... tension roller 13 ... belt unit side frame 13A ... bearing portion 13C, 13S ... compression coil spring 14 ... stopper member 14B ... concave portion P ... paper

Claims (9)

A toner cartridge containing toner;
An endless belt that is laid between a plurality of rollers and rotationally driven is provided, and the toner cartridge is configured to be detachable, and an image of toner contained in the toner cartridge using the endless belt is recorded on a recording medium. An image forming unit to be formed;
A biasing member that biases at least one of the rollers in a direction in which tension is applied to the endless belt;
A relaxed position that supports the at least one roller at a position that does not apply tension to the endless belt against the biasing force of the biasing member, and tension that does not prevent the biasing of the at least one roller by the biasing member A stopper member that is movably provided at a position;
With
When the stopper member is disposed in the relaxed position, the stopper member remains in the relaxed position without moving until the toner cartridge is mounted on the image forming unit, and the toner cartridge is in the image forming unit. An image forming apparatus that moves from the relaxed position to the tensioned position when attached to the camera. The image forming unit includes:
An electrostatic latent image carrier on which an electrostatic latent image is formed is configured to be detachable from the endless belt, and the toner cartridge is configured to be detachable and attached to itself. An image forming cartridge that forms a toner image corresponding to the electrostatic latent image on the surface of the electrostatic latent image carrier using the toner contained in
Prepared,
The endless belt transfers a toner image formed on the surface of the electrostatic latent image carrier to a recording medium;
When the stopper member is disposed at the relaxed position and the image forming cartridge not mounted with the toner cartridge is mounted on the image forming unit, the stopper member is not moved and is moved to the relaxed position. When the image forming cartridge on which the toner cartridge is mounted is mounted on the image forming portion when the image forming cartridge is mounted on the image forming portion when the toner cartridge is disposed at the relaxed position, the image forming cartridge moves from the relaxed position to the tension position. The image forming apparatus according to claim 1.   The stopper member is provided so as to be able to contact the toner cartridge mounted on the image forming cartridge, and when the stopper member is disposed at the relaxed position, the image forming cartridge not mounted with the toner cartridge is When the toner cartridge is mounted, the toner cartridge is not pressed and does not move and stays in the relaxed position. When the toner cartridge is disposed in the relaxed position, the image with the toner cartridge mounted thereon The image forming apparatus according to claim 2, wherein when the forming cartridge is mounted on the image forming unit, the toner cartridge is pressed to move from the relaxed position to the tensioned position. As the plurality of rollers, a driving roller that rotationally drives the endless belt, and a driven roller that rotates following the endless belt and stretches the endless belt at a position in contact with the electrostatic latent image carrier. ,
The image forming apparatus according to claim 2, wherein the at least one roller is the driven roller. The image forming unit includes a plurality of the image forming cartridges configured to be detachable from the endless belt,
The stopper member is provided so as to be in contact with the toner cartridge mounted on the specific image forming cartridge mounted closest to the driven roller among the plurality of image forming cartridges, and is disposed at the relaxed position. And when the specific image forming cartridge not attached with the toner cartridge is attached to the image forming unit, the toner cartridge is not pressed and remains in the relaxed position without moving. When the specific image forming cartridge on which the toner cartridge is mounted is mounted on the image forming portion when the toner cartridge is disposed at the relaxed position, the toner cartridge is pressed against the tension position from the relaxed position. The image forming apparatus according to claim 4, wherein The image forming unit includes:
The toner cartridge includes an electrostatic latent image carrier having an electrostatic latent image formed on a surface thereof, and is configured to be detachable from the endless belt, and uses the toner contained in the toner cartridge. An image forming cartridge for forming a toner image corresponding to the electrostatic latent image on the surface of the latent image carrier;
Prepared,
The endless belt transfers a toner image formed on the surface of the electrostatic latent image carrier to a recording medium;
When the stopper member is disposed at the relaxed position and the image forming cartridge including the toner cartridge is not mounted on the image forming portion, the stopper member remains at the relaxed position without moving. 2. The apparatus according to claim 1, wherein when the image forming cartridge including the toner cartridge is attached to the image forming unit when the image forming cartridge is disposed in the relaxed position, the image forming cartridge moves from the relaxed position to the tensioned position. The image forming apparatus described. As the plurality of rollers, a driving roller that rotationally drives the endless belt, and a driven roller that rotates following the endless belt and stretches the endless belt at a position in contact with the electrostatic latent image carrier. ,
The image forming apparatus according to claim 6, wherein the at least one roller is the driven roller. The image forming unit includes a plurality of the image forming cartridges configured to be detachable from the endless belt,
The stopper member is provided so as to be in contact with the toner cartridge included in the specific image forming cartridge mounted closest to the driven roller among the plurality of image forming cartridges, and is disposed at the relaxed position. When the specific image forming cartridge including the toner cartridge is not attached to the image forming portion, the toner cartridge is not pressed and stays in the relaxed position without moving and remains in the relaxed position. When the specific image forming cartridge including the toner cartridge is mounted on the image forming unit, the toner cartridge is pressed to move from the relaxed position to the tensioned position. The image forming apparatus according to claim 7. As the plurality of rollers, a driving roller that rotationally drives the endless belt, a driven roller that is driven to rotate by the endless belt and stretches the endless belt at a contact position with the electrostatic latent image carrier, and the endless belt A tension roller that applies tension to the belt,
The image forming apparatus according to claim 1, wherein the at least one roller is the tension roller.

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