JP5159160B2 - Image forming apparatus - Google Patents

Description

  The present invention relates to an image forming apparatus using an electrophotographic recording system such as a laser printer, a copying machine, a facsimile, and the like, and more particularly to an apparatus having an intermediate transfer belt and toner containing means.

  A conventional image forming apparatus employs an intermediate transfer belt that temporarily holds a toner image on a photosensitive drum before it is transferred to a recording material (see Patent Document 1).

  FIG. 5 is a longitudinal sectional view showing a schematic configuration of an example of a conventional image forming apparatus using an intermediate transfer belt (intermediate transfer member).

  In this configuration, Y (yellow), M (magenta), C (cyan), and Bk (black) colors are sequentially transferred and superposed on each rotation of the rotating intermediate transfer belt, and then collectively onto the recording material. This is a so-called 4-pass or 4-cycle color image forming apparatus that performs secondary transfer.

  The photosensitive drum (image carrier) 101 that is rotationally driven in the direction of the arrow R1 is uniformly charged by the charging roller 102, and then is irradiated with a laser beam L corresponding to the image information by the exposure device 103 to cause electrostatic latent image on the surface. An image is formed.

  The electrostatic latent image is developed as a toner image by attaching toner to four color developing devices (Y developing device 104a, M developing device 104b, C developing device 104c, and Bk developing device 104d). The four-color developing devices are supported by a developing device 104 called a rotary unit or a carousel.

  This toner image is primarily transferred by a primary transfer roller (primary transfer member) 106 to an intermediate transfer belt 105 that is rotationally driven in the direction of arrow R2 at a primary transfer nip portion (primary transfer portion) N1. In this example, each developing device is disposed above the primary transfer nip portion N1. Then, the primary transfer residual toner on the surface of the photosensitive drum 101 after the completion of the primary transfer is removed by the photosensitive drum cleaning device 108 and used for the next image formation.

  The above charging, exposure, development, primary transfer, and cleaning processes are performed for the remaining three colors, that is, magenta, cyan, and black. That is, the developing device 104 is rotated in the R3 direction every 90 °, and the four color toner images are sequentially superimposed on the transfer belt 105.

  These four color toner images on the intermediate transfer belt 105 are transferred in the direction of arrow K by the secondary transfer roller (secondary transfer member) 107 at the secondary transfer nip portion (secondary transfer portion) N2. Secondary transfer is performed collectively on the material (recording material) P. Thereafter, the unfixed toner image is fixed on the transfer material P by the fixing device 110.

  The secondary transfer residual toner on the intermediate transfer belt 105 after the completion of the secondary transfer is separated from the toner on the intermediate transfer belt 105 by a roller-shaped electrostatic cleaning device (contact charging member) 109 that cleans the intermediate transfer belt. A charge of opposite polarity is imparted. The charged toner is reversely transferred onto the photosensitive drum 101, and then the toner is removed by the photosensitive drum cleaning device 108 and collected in a waste toner container.

  More specifically, the secondary transfer residual toner to which the charge of reverse polarity is applied has a polarity that is attracted to the photosensitive drum by the primary transfer bias. Therefore, the secondary transfer residual toner is transferred from the intermediate transfer belt 105 through the primary transfer nip portion N1 to the photosensitive drum at the same time as the toner image on the photosensitive drum 101 is primarily transferred to the intermediate transfer belt 105 at the primary transfer nip portion N1. 101 is reversely transcribed onto it.

This secondary transfer residual toner is collected by the photosensitive drum cleaning device 108 together with the primary transfer residual toner. The photosensitive drum cleaning device 108 includes a toner conveying unit 113 and can accommodate more waste toner. The secondary transfer residual toner may be cleaned by combining a cleaning blade or a cleaning roller and a dedicated collection container in addition to the method shown here.
JP 2005-70206 A

  By the way, in the above conventional example, the space for arranging the cleaner, that is, the waste toner container is limited to the region above the surface on the intermediate transfer belt where the primary transfer nip portion is located, so that it is difficult to increase the capacity. When the waste toner container is installed in another place in order to secure the capacity, a transport means for transporting the waste toner is required, which complicates the configuration and increases the manufacturing cost.

In order to solve the above problems, the present invention provides an image carrier that carries a toner image, an intermediate transfer belt that is in contact with the image carrier and onto which the toner image on the image carrier is transferred, and the image carrier after transfer. A cleaning member that scrapes off the toner remaining on the surface, and a storage unit that stores the toner scraped off by the cleaning member, and the intermediate transfer belt is viewed from the rotation axis direction of the image carrier, The intermediate transfer belt is disposed under the image carrier over the entire width in the horizontal direction of the image carrier, and the intermediate transfer belt is disposed below the image carrier at a contact portion between the image carrier and the intermediate transfer belt. in the image forming apparatus, the housing means comprises a container for containing the toner, which is arranged in the next horizontal edge of the front Symbol intermediate transfer belt in the horizontal direction, it scraped off by the cleaning member Receive toner A toner guide surface that guides to the housing portion, wherein the toner guide surface is a surface that extends from directly below the cleaning member to the housing portion and is inclined downward toward the housing portion. To do.

  As described above, according to the present invention, it is possible to increase the capacity of the toner storage unit with respect to the toner storage unit in the image forming apparatus. Accordingly, it is possible to eliminate the need for replacement of the storage means over a long period.

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

(First embodiment)
FIG. 1 is a longitudinal sectional view showing a schematic configuration of an image forming apparatus according to the first embodiment of the present invention. The image forming apparatus shown in FIG. 1 is an electrophotographic four-color (four-pass) full-color laser beam printer, and uses an intermediate transfer member.

First, the configuration of the image forming apparatus in the present embodiment will be described.
The image forming apparatus shown in FIG. 1 includes a drum-type electrophotographic photosensitive member (hereinafter referred to as a photosensitive drum) 1 as a first image carrier that carries a toner image. The photosensitive drum 1 is configured by providing a photoconductive layer on the outer peripheral surface of an aluminum cylinder. The photosensitive drum 1 is rotatably supported by an image forming apparatus main body (hereinafter referred to as an apparatus main body), and is rotationally driven in the direction of arrow R1 by a driving unit (not shown).

  Around the photosensitive drum 1, a charging roller 2, an exposure device 3, a developing device 4, an intermediate transfer belt (intermediate transfer member) 5, a cleaning blade 8, and the like are arranged almost sequentially along the rotation direction. The charging roller 2 serving as charging means is of a contact type that uniformly charges the surface of the photosensitive drum 1. An exposure device 3 as exposure means irradiates the surface of the photosensitive drum 1 with laser light L in accordance with image information to form an electrostatic latent image. The developing device 4 that is a developing means is mounted on a rotary developing member called a rotary unit or a carousel, and develops each color of yellow, magenta, cyan, and black by developing the toner image by attaching toner to the electrostatic latent image. 4a, 4b, 4c, 4d. The intermediate transfer belt 5 as the second image carrier is in contact with the photosensitive drum 1, and the toner image on the photosensitive drum 1 (on the first image carrier) is transferred (primary transfer). The cleaning means is a cleaning blade 8 which is a removing means for removing toner (transfer residual toner) remaining on the photosensitive drum after transfer, and a waste which is a storage means for storing the toner (waste toner) removed by the cleaning blade. And a toner container 13.

  The exposure device 3 includes a laser oscillator (not shown) that emits laser light L according to image information, a polygon mirror 3a as a device that scans the laser light, a mirror 3b, and the like, and is charged according to image information. The surface of the photosensitive drum 1 thus exposed is exposed to form an electrostatic latent image.

  Here, since the developing devices 4a, 4b, 4c, and 4d are configured as developing cartridges, they can be replaced by the user. The user can also replace the process cartridge 30 including the photosensitive drum 1, the charging roller 2, the cleaning blade 8, the waste toner container 13, and the like.

  By opening the door panel 16 which is an opening / closing member provided in front of the apparatus main body (right direction in FIG. 1), the user can access the developing devices 4a, 4b, 4c, 4d and the process cartridge 30. That is, the opening / closing member 16 is provided on the opposite side of the image carrier 1 with respect to the accommodating means 13, and the opening / closing member 16 can be opened and closed with respect to the apparatus main body. When the opening / closing member 16 is opened, an opening is formed in the apparatus main body, and the developing cartridge and the process cartridge can be attached and detached from this opening. At this time, by rotating the rotary developing device 4, the target developing device is moved to the replacement position.

  The intermediate transfer belt 5 is formed in an endless shape, is wound around two support rollers (rotating members) 14 and 15 arranged in parallel to each other, and is arranged almost horizontally. One of the two support rollers is a drive roller, and the remaining one is a driven roller. The intermediate transfer belt 5 is driven (traveled) in the direction of the arrow R <b> 2 when a driving roller is rotated by a driving unit (not shown). A primary transfer roller 6 as a primary transfer member is disposed inside the intermediate transfer belt 5 and presses the intermediate transfer belt 5 against the surface of the photosensitive drum 1 by a pressing unit (not shown). The photosensitive drum 1 and the primary transfer roller 6 are pressed against each other via the intermediate transfer belt 5 to form a primary transfer nip portion N1. That is, the intermediate transfer belt is in contact with the image carrier, and a contact portion is formed between the image carrier and the intermediate transfer belt. A primary transfer bias is applied to the primary transfer roller 6 by a power source (not shown).

  A secondary transfer roller 7 as a secondary transfer member is disposed outside the intermediate transfer belt 5, and the support roller 14 and the secondary transfer roller 7 are pressed against each other via the intermediate transfer belt 5. A transfer nip portion N2 is formed. A secondary transfer bias is applied to the secondary transfer roller 7 by a power source (not shown).

  Further, on the downstream side of the secondary transfer nip portion N2 and the upstream side of the primary transfer nip portion N1, the electrostatic intermediate transfer belt cleaning device 9 (roller charger) is arranged so as to face the intermediate transfer belt 5. Is arranged. The electrostatic intermediate transfer belt cleaning device 9 is disposed so as to be in contact with the surface of the intermediate transfer belt 5 and has a power source (not shown).

  Then, the unfixed toner image transferred onto the transfer material P is downstream of the secondary transfer nip portion N2 with respect to the transfer direction (arrow K direction) of the transfer material P fed and conveyed from the paper feed cassette 11. A fixing device 10 for fixing by heating and pressing is provided.

  Next, the operation of the image forming apparatus having the above configuration will be described.

  The surface of the photosensitive drum 1 that is rotationally driven in the direction of the arrow R1 is uniformly charged when a charging bias in which a DC voltage and an AC voltage are superimposed is applied to the charging roller 2. When a yellow image signal is input to a laser oscillator (not shown), laser light L is emitted, and the surface of the charged photosensitive drum 1 is irradiated to form an electrostatic latent image. When the photosensitive drum 1 further rotates in the direction of the arrow R1, the yellow toner is attached to the electrostatic latent image on the photosensitive drum 1 and is developed as a toner image. The yellow toner image on the photosensitive drum 1 is primarily transferred onto the intermediate transfer belt 5 at the primary transfer nip portion N1 by the primary transfer bias applied to the primary transfer roller 6. The photosensitive drum 1 after the toner image transfer is prepared for the next image formation by removing the primary transfer residual toner on the surface by the cleaning device 8. The removed transfer residual toner is collected in a waste toner container 13.

  By repeating the above-described series of image forming processes of charging, exposure, development, primary transfer, and cleaning for the other three colors, that is, magenta, cyan, and black, a four-color toner image is formed on the intermediate transfer belt 5. Is formed. The rotary developing device 4 includes four color developing devices, that is, a yellow developing device 4a, a magenta developing device 4b, a cyan developing device 4c, and a black developing device 4d. Then, by the rotation of the developing device 4, a developing device used for developing the electrostatic latent image on the photosensitive drum 1 is disposed at a developing position facing the surface of the photosensitive drum 1.

  When forming a four-color full-color image, the developing device 4 is rotated every 90 °, and each developing device is sequentially arranged at the developing position. In this embodiment, since the developing position of the developing device at the time of development is upward with respect to the transfer nip N1, a complicated configuration such as so-called pumping development in which the toner is transported from the bottom to the top in the developing device is required. There is no.

  The toner images superimposed in four colors on the intermediate transfer belt 5 in this way are transferred in the direction of the arrow K at the secondary transfer nip portion N2 by the secondary transfer bias applied to the secondary transfer roller 7 by a power source (not shown). After being secondarily transferred to the transfer material P that has been conveyed to the sheet, the sheet is discharged to the sheet discharge tray 12. As a result, a four-color full-color image is obtained on the transfer material.

  On the other hand, the secondary transfer residual toner remaining on the surface of the intermediate transfer belt 5 after transferring the toner image without being transferred to the transfer material P is given a reverse polarity, that is, a positive charge by the intermediate transfer belt cleaning device 9. As a result, the secondary transfer residual toner is reversely transferred onto the photosensitive drum 1 through the primary transfer nip portion N1 and cleaned by the cleaning blade 8. The reversely transferred secondary transfer residual toner is removed by the cleaning device 8 together with the primary transfer residual toner on the photosensitive drum 1 and collected in the waste toner container 13.

  Here, features unique to the present embodiment will be described.

  The waste toner container 13 constituting the process cartridge is installed with a primary transfer nip portion N1 interposed therebetween with respect to a developing device that performs development. Here, the installation condition can be configured as installation above and below the primary transfer nip portion N1.

  That is, the waste toner container 13 is provided at the end of the intermediate transfer belt 5 with respect to the moving direction of the intermediate transfer belt 5 and straddles the contact portion between the photosensitive drum and the intermediate transfer belt in the arrangement direction of the photosensitive drum and the intermediate transfer belt. Is provided. Specifically, the waste toner container extends from the image carrier side (photosensitive drum side) to the rotating member side (support roller side) around which the intermediate transfer belt is wound. In this embodiment, the arrangement direction of the photosensitive drum and the intermediate transfer belt is a vertical direction.

  Further, there is no means for transporting toner in the waste toner container 13. Therefore, the transfer residual toner scraped off by the cleaning blade 8 falls in the waste toner container 13 only by the action of gravity. The direction in which the toner is dropped is the belt conveyance direction, that is, the direction indicated by the arrow 18 in FIG. In this embodiment, the angle of the surface 17 on which the toner slides when dropped as shown in FIG. 1 is set to about 50 degrees with respect to the horizontal. This angle is preferably 45 degrees or more empirically.

  In the configuration in which the developing position of the developing unit at the time of development is downward with respect to the primary transfer nip portion N1, it is easy to drop and collect the waste toner, but on the other hand, the toner in the developing unit Therefore, a complicated structure such as so-called pumping development is required. In this embodiment, the toner feeding mechanism in the waste toner collecting unit can be omitted and the capacity of the waste toner container can be increased without using such a complicated developing device configuration.

  In this embodiment, as shown in FIG. 1, the intermediate transfer belt 5 is stretched by two axes, and the installation angle is substantially horizontal. The advantage of this configuration is that it reduces wasted space on the inner surface of the belt compared to the triaxial stretcher, and lowers the height of the main body of the device compared to the case where the angle of the intermediate transfer belt is inclined or vertical. Therefore, it is advantageous for downsizing.

  Even when the angle of the belt is made closer to the horizontal, as shown in FIG. 1, the primary transfer nip N1 is arranged at the end of the intermediate transfer belt 5 in the conveyance direction, and the toner is dropped by its own weight from the intermediate transfer belt conveyance surface side. Can do. Thus, waste toner can be easily collected in a waste toner container having a large capacity without using a toner transport mechanism.

  With the above configuration, a simple configuration in which the toner conveying unit is omitted can be realized, and the capacity of the waste toner container can be increased. Therefore, it is not necessary to replace the process cartridge 30 over a long period of time. it can.

  When the opening / closing member 16 is opened, the accommodating means 13 covers the image carrier and the intermediate transfer belt as viewed from the opening formed in the apparatus main body. That is, the fact that the waste toner container 13 has a space extending above and below the primary transfer nip portion N1 has an effect of protecting the photosensitive drum 1 from being exposed to light. As shown in FIG. 5, when the waste toner container 108 is only above the primary transfer nip N1, when the user opens the door panel, such as when the developer is replaced, light enters from the arrow 111 and the photosensitive drum becomes light. There was a risk of image defects due to exposure. In this embodiment, as shown in FIG. 1, since the front surface of the photosensitive drum 1 is covered from the top and bottom of the primary transfer nip portion N1, exposure to light can be prevented. Here, it is preferable to form a suitable portion of the waste toner container with a colored member such as black suitable for light shielding so as to provide light shielding properties.

  The fact that the waste toner container 13 has a space extending above and below the transfer nip N1 also has an effect of protecting the intermediate transfer belt 5. As shown in FIG. 5, when the waste toner container 108 is only above the primary transfer nip portion N1, the front side of the intermediate transfer belt 105 in the apparatus main body is exposed when the user opens the door panel, such as when the developer is replaced. For this reason, there is a risk that the user may accidentally touch or hurt. In this embodiment, as shown in FIG. 1, the intermediate transfer belt 5 can be protected because the intermediate transfer belt 5 covers the front side of the apparatus body over the upper and lower sides of the primary transfer nip portion N1.

  In addition, this configuration has an advantage that it is not necessary to provide a separate belt cleaning collector because the waste toner container 13 serves both for collecting primary transfer residual toner and secondary transfer residual toner. In this configuration, since the capacity of the waste toner container 13 can be increased, there is a sufficient margin for collecting both the primary transfer residual toner and the secondary transfer residual toner.

(Second Embodiment)
FIG. 3 is a schematic view showing an image forming apparatus according to the second embodiment of the present invention. The basic part of the configuration of the image forming apparatus according to the present embodiment is substantially the same as that of the first embodiment. Therefore, the description of the same part is omitted, and different parts are mainly described.

  First, a characteristic configuration of the present embodiment will be described.

  The image forming apparatus shown in FIG. 3 is an inline image forming apparatus in which process cartridges are arranged in a straight line. A photosensitive drum cleaning device including a developing device, a photosensitive drum, and a waste toner container is integrated as a unit that can be replaced by a user. This unit is defined as a process cartridge. Of the configurations commonly used in the process cartridges, only one portion is numbered and the rest are omitted for those portions that can be clearly identified as the same product from the drawing.

  Four drum-type photosensitive drums 21 as the first image carrier are arranged opposite to the intermediate transfer belt 5. The toner images on the photosensitive drum 21 are primarily transferred onto the intermediate transfer belt 5 by primary transfer rollers 26 a, 26 b, 26 c, and 26 d disposed so as to face the photosensitive drum 21 with the intermediate transfer belt 5 interposed therebetween. . The photosensitive drum 21 is rotatably supported by the apparatus main body, and is rotationally driven in the direction of arrow R1 by a driving unit (not shown).

  Around the photosensitive drum 21, a charging roller 22, an exposure device 23, developing devices 24a, 24b, 24c, and 24d, and waste toner containers 25a, 25b, 25c, and 25d are arranged in this order along the rotation direction. The charging roller 22 is of a contact type that uniformly charges the surface of the photosensitive drum 1. The exposure device 23 forms an electrostatic latent image by irradiating the surface of the photosensitive drum 1 with laser light L in accordance with image information. The yellow, magenta, cyan, and black developing devices 24a, 24b, 24c, and 24d develop toner images by attaching toner to the electrostatic latent image. The waste toner containers 25a, 25b, 25c, and 25d are combined with each other to form a process cartridge.

  Here, among the four process cartridges, only the waste toner container 25d of one process cartridge located at the end is installed with respect to the developing device 24d that performs development with the transfer nip N1 interposed therebetween. Here, the installation condition can be configured as installation above and below the transfer nip N1. That is, with respect to the arrangement direction of the photosensitive drum and the intermediate transfer belt, the waste toner container is provided across the contact portion between the photosensitive drum and the intermediate transfer belt. Specifically, the waste toner container extends from the photosensitive drum side to the support roller side around which the intermediate transfer belt is wound. In this embodiment, the arrangement direction of the photosensitive drum and the intermediate transfer belt is a vertical direction.

  Further, among the four waste toner containers, at least the waste toner container 25d is characterized in that it does not have means for transporting toner inside. The process cartridge is replaced by opening the door panel 16 on the front side of the apparatus (right direction in the drawing) and pulling out a rail (not shown) that holds the four process cartridges.

Next, the operation of the image forming apparatus having the above configuration will be described.
The surface of the photosensitive drum 21 that is rotationally driven in the direction of the arrow R 1 is uniformly charged by the charging roller 22. Four laser beams L are emitted from the exposure device 23, and the surface of the charged photosensitive drum 21 is irradiated to form an electrostatic latent image. Each of the photosensitive drums 21 further rotates in the arrow R1 direction, and the toner images of the respective colors are developed by the developing devices 24a, 24b, 24c, and 24d with respect to the electrostatic latent image on the photosensitive drum 21.

  The developed toner images of the respective colors are primarily transferred onto the intermediate transfer belt 5 continuously at the primary transfer nip N1 of the primary transfer rollers 26a, 26b, 26c, and 26d facing the respective photosensitive drums 21. . By superimposing these, a full-color toner image is formed on the intermediate transfer belt 5. After the toner image is transferred, the surface of the photosensitive drum 21 is prepared for the next image formation by removing the primary transfer residual toner on the surface by the cleaning blade 28. The removed primary transfer residual toner is collected in waste toner containers 25a, 25b, 25c, and 25d, respectively.

  The toner images superimposed in four colors on the intermediate transfer belt 5 in this way are transferred in the direction of the arrow K at the secondary transfer nip portion N2 by the secondary transfer bias applied to the secondary transfer roller 7 by a power source (not shown). Secondary transfer is performed on the transfer material P that has been transported to the surface.

  After the toner image is secondarily transferred to the transfer material P, the intermediate transfer belt 5 is not transferred to the transfer material P, but the secondary transfer residual toner remaining on the surface is reversed by the intermediate transfer belt cleaning device 9. Charge is applied. As a result, the secondary transfer residual toner is reversely transferred onto the photosensitive drum 1 via the primary transfer nip portion N1 and is collected in a waste toner container, which is the same as in the first embodiment. This part has the characteristics of this embodiment.

  In the present embodiment, only the waste toner container 25d of one process cartridge at the end of the four developing cartridges is installed over the surface where the primary transfer nip portion N1 is located. Further, there is no means for transporting toner into at least the waste toner container 25d among the four waste toner containers.

  When there is no continuous print job or after jam processing, for example, a negative bias is applied to the primary transfer rollers 26a, 26b, and 26c among the four primary transfer rollers, and a positive bias is applied only to 26d. As a result, the secondary transfer residual toner to which a positive charge is applied can be positively collected in the waste toner container 25d having the largest capacity. By doing so, for example, it is possible to prevent the waste toner from becoming full before the unused toner is used up and the process cartridge must be replaced.

  The transfer residual toner scraped off by the cleaning blade 28 in the waste toner container 25d falls in the waste toner container 25d only by the action of gravity. The direction in which the toner is dropped is the belt conveyance direction, that is, the direction indicated by the arrow 18 in FIG. 2, as in the first embodiment. Also in this embodiment, the angle of the surface 17 where the toner slides when dropped as shown in FIG. 3 is set to about 50 degrees with respect to the horizontal. With the above configuration, a simple configuration in which the toner conveying unit is omitted can be realized.

  In the configuration in which the developing position of the developing unit at the time of development is downward with respect to the primary transfer nip portion N1, it is easy to drop and collect the waste toner, but on the other hand, the toner in the developing unit Therefore, a complicated structure such as so-called pumping development is required. In this embodiment, the toner feeding mechanism in the waste toner collecting unit can be omitted and the waste toner container capacity can be increased without using such a complicated developing device configuration.

  In this embodiment, as shown in FIG. 3, the intermediate transfer belt 5 is stretched by two axes, and the installation angle is substantially horizontal. The advantage of this configuration is that it reduces wasted space on the inner surface of the belt compared to the triaxial stretcher, and lowers the height of the main body of the device compared to the case where the angle of the intermediate transfer belt is inclined or vertical. Therefore, it is advantageous for downsizing. Even when the angle of the belt is close to horizontal, as shown in FIG. 3, the primary transfer nip portion N1 is disposed at the end of the intermediate transfer belt 5 in the conveyance direction, and the toner is dropped by its own weight from the intermediate transfer belt conveyance surface side. be able to. Thus, waste toner can be collected in a waste toner container having a large capacity without using a toner transport mechanism.

  With the above configuration, a simple configuration in which the toner conveying unit is omitted can be realized, and the capacity of the waste toner container can be increased. Therefore, the configuration in which the secondary transfer residual toner is shared with the photosensitive drum cleaning by the electrostatic belt cleaning device is effective.

  The fact that the waste toner container 25d has a space extending above and below the primary transfer nip N1 has an effect of protecting the photosensitive drum 21 from being exposed to light.

  As shown in FIG. 4, it is assumed that the waste toner container 125d is only above the primary transfer nip portion N1 like the other waste toner containers 25a, 25b, and 25c. In that case, when the user opens the door panel 16, the photosensitive drum may be exposed to light as indicated by an arrow 200 to cause image defects.

  In this embodiment, as shown in FIG. 3, since the front surface of the photosensitive drum 1 is covered from the top and bottom of the primary transfer nip portion N1, exposure to light can be prevented. Here, it is also preferable to mold an appropriate portion of the waste toner container 25d with a colored member such as black suitable for light shielding.

  The fact that the waste toner container 25d has a space extending above and below the primary transfer nip portion N1 also has an effect of protecting the intermediate transfer belt 5. As shown in FIG. 4, when the waste toner container 125d is only above the primary transfer nip N1, like the other waste toner containers 25a, 25b, 25c, when the user opens the door panel 16, the device of the intermediate transfer belt 5 is used. The front side of the main unit is exposed. For this reason, there is a risk that the user may accidentally touch or hurt.

  In the present embodiment, the intermediate transfer belt 5 can be protected because the intermediate transfer belt 5 covers the front side of the apparatus body over the upper and lower sides of the primary transfer nip portion N1.

  As described above, according to the above-described embodiment, the waste toner container capacity can be increased without using the toner transport mechanism in the waste toner collecting unit in the image forming apparatus. Accordingly, it is possible to simplify the configuration and make it unnecessary to replace the waste toner container over a long period of time.

  Further, according to the embodiment, since the primary transfer residual toner and the secondary transfer residual toner are collected in the same waste toner container, the configuration can be simplified. However, for this purpose, it is necessary to increase the capacity of the waste toner container, but in this configuration, it is possible to increase the capacity of the waste toner container. In addition, if there is a separate collection chamber corresponding to each, and these constitute a unit integrally with the photosensitive drum, the entire unit is replaced when one of the collection chambers is full You can solve the problem that you have to do.

  According to the embodiment, for example, in an image forming apparatus in which the apparatus main body is downsized by laying the intermediate transfer belt at a substantially horizontal angle, the toner is supplied from the intermediate transfer belt conveyance surface side with respect to the waste toner container included in the process cartridge. Can be dropped by its own weight. Thus, waste toner can be collected in a waste toner container having a large capacity without using a toner transport mechanism. Therefore, the configuration can be simplified and the frequency of waste toner replacement can be reduced.

1 is a diagram illustrating an image forming apparatus according to an embodiment of the present invention. The figure which shows a cleaning part. The figure which shows the image forming apparatus which is other embodiment of this invention. The figure which shows the background art of this invention. 1 is a diagram illustrating a conventional image forming apparatus.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Photosensitive drum 4 Developing apparatus 5 Intermediate transfer belt 8 Cleaning blade 13 Waste toner container 14 Support roller 15 Support roller 16 Door panel 17 Toner falling surface

Claims (6)

An image carrier that carries a toner image, an intermediate transfer belt that is in contact with the image carrier and onto which the toner image on the image carrier is transferred, and a cleaning member that scrapes off toner remaining on the image carrier after transfer And an accommodating means for accommodating the toner scraped off by the cleaning member, and the intermediate transfer belt is located below the image carrier when viewed from the rotational axis direction of the image carrier. disposed laterally across the entire width of the body, at the contact portion between the intermediate transfer belt and the image bearing member, the intermediate transfer belt in an image forming apparatus which is arranged on the lower side of the image bearing member,
It said housing means comprises a container for containing the toner, which is arranged in the next horizontal edge of the front Symbol intermediate transfer belt in the horizontal direction, receiving the toner scraped off by the cleaning member, the receiving portion A toner guide surface for guiding to
The image forming apparatus according to claim 1, wherein the toner guide surface is a surface that extends from directly below the cleaning member to the housing portion and is inclined downward toward the housing portion.   The image forming apparatus according to claim 1, further comprising an opening / closing member on an opposite side of the image carrier with respect to the housing unit, wherein the opening / closing member is openable / closable with respect to the apparatus main body.   3. The image forming apparatus according to claim 2, wherein when the opening / closing member is opened, the housing means covers the image carrier and the intermediate transfer belt as viewed from the side of the opening formed in the apparatus main body. apparatus.   The image forming apparatus according to claim 3, further comprising a developing unit that develops the latent image formed on the image carrier, wherein the developing unit is detachable from the opening.   The image forming apparatus according to claim 2, wherein the housing unit is formed of a light shielding member.   6. The toner remaining on the intermediate transfer belt is reversely transferred to the image carrier, scraped off by the cleaning member, and stored in the storage unit. Image forming apparatus.

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