Waste toner recovery device and image forming apparatus

Abstract

To recover waste toner without almost any waste as a whole, including an upstream-side area of an upper-stage recovery part of a waste toner recovery device that is partitioned into two recovery parts.SOLUTION: A waste toner recovery device is provided with: an upper-stage recovery part A that is provided with an upper-stage discharge port 35T; a lower-stage recovery part B that is partitioned by a partition wall 32 from the upper-stage recovery part A, and is provided with lower-stage discharge ports 35Y, 35M, 35C, 35K; a communication part 33 that communicates with the upper-stage recovery part A and the lower-stage recovery part B; an upper-stage conveying screw 41 (upper-stage conveying member); and a lower-stage conveying screw 42 (lower-stage conveying member). In an upstream-side area M from an upstream-side inner wall part 31a to the upper-stage discharge port 35T located at an upstream-side end in a conveyance direction, a low conveyance performance part N is formed where the conveyance performance of waste toner T in the conveyance direction is lower than the conveyance performance in an area V on the downstream side of the upstream-side area M.SELECTED DRAWING: Figure 3

Description

Technical Field

[0001] The present invention relates to a waste toner collection device for collecting waste toner, and an image forming apparatus such as a copying machine, a printer, a facsimile machine, or a multifunction machine equipped with the same.

Background Art

[0002] Conventionally, in image forming apparatuses such as copying machines and printers, after the transfer process is performed, untransferred toner remaining on an image carrier such as a photosensitive drum, a photosensitive belt, an intermediate transfer belt, or an intermediate transfer drum is removed by a cleaning device, and the untransferred toner collected by the cleaning device is discharged from the cleaning device as waste toner and collected in a waste toner collection device (waste toner container) (see, for example, Patent Document 1).

[0003] On the other hand, Patent Document 1 discloses a technique in which the inside of a waste toner collection device is partitioned by a partition wall into two collection parts, an upper-stage collection part and a lower-stage collection part, the waste toner discharged to the upper-stage collection part is conveyed by an upper-stage conveying member and caused to flow into the lower-stage collection part through a communication part, and the waste toner discharged to the lower-stage collection part is conveyed by a lower-stage conveying member to the side away from the communication part, and the waste toner is collected in each collection part.

Summary of the Invention

Problems to be Solved by the Invention

[0004] Although the technique of Patent Document 1 can sufficiently be expected to have an effect of reducing the problem that a large useless space in which waste toner cannot be collected is generated inside the waste toner collection device, a useless space in which waste toner cannot be sufficiently collected is generated in the upstream region on the upstream side in the conveying direction in the upper-stage collection part.

[0005] The present invention has been made to solve the above-described problems, and provides a waste toner collection device and an image forming apparatus capable of almost completely collecting waste toner without waste, including the upstream region of the upper collection part in the waste toner collection device partitioned into two collection parts.

Means for Solving the Problems

[0006] The waste toner collection device in the present invention includes an upper collection part having one or a plurality of upper discharge ports, a lower collection part partitioned from the upper collection part by a partition wall and having one or a plurality of lower discharge ports, a communication part communicating with the upper collection part and the lower collection part, an upper conveyance member in the upper collection part for conveying the waste toner discharged from the upper discharge port in the direction of the rotation axis with the direction of the rotation axis as the conveyance direction toward the communication part, and a lower conveyance member in the lower collection part for conveying the waste toner discharged from the lower discharge port and the waste toner flowing in from the communication part in the direction of the rotation axis toward one end side in the direction of the rotation axis away from the communication part. The upper collection part has a low conveyance ability part formed in the upstream region from the upstream inner wall part located at the upstream end part in the conveyance direction to the one upper discharge port or the upper discharge port located most upstream among the plurality of upper discharge ports, where the conveyance ability of the waste toner in the conveyance direction is lower than that in the region downstream of the upstream region.

Effects of the Invention

[0007] According to the present invention, it is possible to provide a waste toner collection device and an image forming apparatus capable of almost completely collecting waste toner without waste, including the upstream region of the upper collection part in the waste toner collection device partitioned into two collection parts.

Brief Description of the Drawings

[0008]

Figure 1

Figure 2

Figure 3

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Mode for Carrying Out the Invention

[0009] Hereinafter, the mode for carrying out this invention will be described in detail with reference to the drawings. In each figure, the same or corresponding parts are denoted by the same reference numerals, and the redundant description will be simplified or omitted as appropriate.

[0010] First, with reference to FIG. 1, the overall configuration and operation of the image forming apparatus 1 will be described. In FIG. 1, 1 is a color copier as an image forming apparatus, 3 is a document conveyance unit that conveys a document to a document reading unit 4, 4 is a document reading unit that reads image information of a document, and 6 is a writing unit (exposure unit) that emits laser light based on input image information. Further, 7 is a paper feeding device for storing a sheet P such as paper, 10Y, 10M, 10C, and 10K are process cartridges as image forming units corresponding to respective colors (yellow, magenta, cyan, black), 17 is an intermediate transfer belt (image carrier) on which toner images of multiple colors are superposed and transferred, and 18 is a secondary transfer roller for transferring the toner image formed on the intermediate transfer belt 17 to the sheet P. Also, 20 is a fixing device for fixing the unfixed image on the sheet P, 28 is a toner container for supplying toner of each color to the developing devices of the respective process cartridges 10Y, 10M, 10C, 10K, and 30 is a waste toner collecting device for collecting waste toner.

[0011] Here, each of the process cartridges 10Y, 10M, 10C, 10K (image forming units) is an integrated unit of a photosensitive drum 11 as an image carrier, a charging device 12, a developing device 13, and a cleaning device 15 (see FIG. 2). And each of the process cartridges 10Y, 10M, 10C, 10K is replaced with a new one when its life is reached. On the photosensitive drum 11 (image carrier) in each of the process cartridges 10Y, 10M, 10C, 10K, toner images of respective colors (yellow, magenta, cyan, black) are formed.

[0012] Hereinafter, the operation during normal color image formation in the image forming apparatus will be described. First, the original document is conveyed from the original document table by the conveying rollers of the original document conveying unit 3 and placed on the contact glass of the original document reading unit 4. Then, in the original document reading unit 4, the image information of the original document placed on the contact glass is optically read. Then, the image information of each color of yellow, magenta, cyan, and black is transmitted to the writing unit 6. And from the writing unit 6, laser light L (exposure light) based on the image information of each color is irradiated onto the photosensitive drums 11 of the corresponding process cartridges 10Y, 10M, 10C, 10K, respectively.

[0013] On one hand, the four photoreceptor drums 11 are each rotating in the clockwise direction in FIGS. 1 and 2. Then, referring to FIG. 2, first, the surface of the photoreceptor drum 11 is uniformly charged at the position facing the charging device 12 (charging roller) (this is the charging process). Thus, a charging potential is formed on the photoreceptor drum 11. After that, the surface of the charged photoreceptor drum 11 reaches the irradiation position of each laser beam L. In the writing unit 6, laser beams L corresponding to the image signals are emitted from the light source for each color. The laser beam L is incident on the polygon mirror and reflected, and then passes through a plurality of lenses. The laser beam after passing through the plurality of lenses will pass through different optical paths for each of the yellow, magenta, cyan, and black color components (this is the exposure process).

[0014] The laser beam corresponding to the yellow component is irradiated onto the surface of the photoreceptor drum 11 of the first process cartridge 10Y from the left side of the paper surface. Thus, an electrostatic latent image corresponding to the yellow component is formed on the photoreceptor drum 11 after being charged by the charging roller 12a. Similarly, the laser beam corresponding to the magenta component is irradiated onto the surface of the photoreceptor drum 11 of the second process cartridge 10M from the left of the paper surface, and an electrostatic latent image corresponding to the magenta component is formed. The laser beam of the cyan component is irradiated onto the surface of the photoreceptor drum 11 of the third process cartridge 10C from the left of the paper surface, and an electrostatic latent image of the cyan component is formed. The laser beam of the black component is irradiated onto the surface of the photoreceptor drum 11 of the fourth process cartridge 10K from the left of the paper surface, and an electrostatic latent image of the black component is formed.

[0015] After that, the surfaces of the photoreceptor drums 11 on which the electrostatic latent images of each color are formed reach the positions facing the developing devices 13 (see FIG. 2) respectively. Then, toners of each color are supplied from each developing device 13 onto the photoreceptor drum 11, and the latent images on the photoreceptor drum 11 are developed (this is the developing process). After that, the surfaces of the photoreceptor drums 11 after the development process respectively reach the opposing positions with the intermediate transfer belt 17 (intermediate transfer member) as the image carrier. Here, at each opposing position, a primary transfer roller 14 is installed so as to contact the inner peripheral surface of the intermediate transfer belt 17. And at the position of the primary transfer roller 14, the toner images of each color formed on the photoreceptor drum 11 are sequentially transferred onto the intermediate transfer belt 17 in an overlapping manner (this is the primary transfer process).

[0016] And the surfaces of the photoreceptor drums 11 after the primary transfer process respectively reach the opposing positions with the cleaning device 15 (see FIG. 2). Then, the untransferred toner remaining on the photoreceptor drum 11 is collected by the cleaning device 15 (this is the cleaning process). After that, the surface of the photoreceptor drum 11 passes through the position of the charge removal device, and a series of image forming processes on the photoreceptor drum 11 are completed.

[0017] On the other hand, the surface of the intermediate transfer belt 17 onto which the images of each color on the photoreceptor drum 11 are transferred in an overlapping manner travels in the direction of the arrow in FIG. 1 and reaches the position of the secondary transfer roller 18. And at the position of the secondary transfer roller 18, the full-color image on the intermediate transfer belt 17 is secondarily transferred onto the sheet P (this is the secondary transfer process). After that, the surface of the intermediate transfer belt 17 reaches the position of the intermediate transfer belt cleaning device 9 (cleaning device). Then, the untransferred toner on the intermediate transfer belt 17 is collected by the intermediate transfer belt cleaning device 9, and a series of transfer processes on the intermediate transfer belt 17 are completed.

[0018] Here, the sheet P at the position of the secondary transfer roller 18 is conveyed from the paper feeding device 7 via a conveyance guide, a registration roller 19, and the like. Specifically, the sheet P fed by the paper feeding roller 8 from the paper feeding device 7 that stores the sheet P is guided to the registration roller 19 after passing through the conveyance guide. The sheet P that has reached the registration roller 19 is conveyed toward the position of the secondary transfer roller 18 in synchronization with the toner image on the intermediate transfer belt 17.

[0019] After that, the sheet P onto which the full-color image has been transferred is guided to the fixing device 20. In the fixing device 20, the color image is fixed onto the sheet P at the nip between the fixing roller and the pressure roller. Then, after the sheet P after the fixing process is discharged as an output image outside the apparatus main body 1 by the paper discharge roller 29, it is stacked on the paper discharge unit 5, and a series of image forming processes is completed.

[0020] Next, with reference to FIG. 2, the image forming section of the image forming apparatus will be described in detail. FIG. 2 is a configuration diagram showing the process cartridge 10K for black. Since the other three process cartridges 10Y, 10M, and 10C are configured substantially the same as the process cartridge 10K for black, except that the color of the toner used in the image forming process is different, their illustration and description are omitted.

[0021] As shown in FIG. 2, the process cartridge 10K integrally houses in a case a photosensitive drum 11 as an image carrier, a charging device 12 for charging the photosensitive drum 11, a developing device 13 for developing the electrostatic latent image formed on the photosensitive drum 11, and a cleaning device 15 for collecting the untransferred toner on the photosensitive drum 11.

[0022] Here, the photosensitive drum 11 is a negatively chargeable organic photosensitive member having a photosensitive layer and the like provided on a drum-shaped conductive support. The charging device 12 is a charging roller formed by coating the outer periphery of a conductive core bar with a medium-resistance elastic layer. Then, a predetermined voltage is applied to this charging device 12 (charging roller) from a power supply unit, thereby uniformly charging the surface of the opposing photosensitive drum 11.

[0023] The developing device 13 mainly includes a developing roller 13a facing the photosensitive drum 11, a first conveying screw 13b1 facing the developing roller 13a, a second conveying screw 13b2 facing the first conveying screw 13b1 via a partition member, and a doctor blade 13c facing the developing roller 13a. The developing roller 13a is composed of a magnet fixedly installed inside and forming magnetic poles on the roller circumferential surface, and a sleeve rotating around the magnet. A plurality of magnetic poles are formed on the developing roller 13a (sleeve) by the magnet, and the developer is carried on the developing roller 13a. Inside the developing device 13, a two-component developer composed of carrier and toner is accommodated.

[0024] The cleaning device 15 is provided with a cleaning blade 15a that contacts the photosensitive drum 11, a conveying coil 15b (conveying pipe 16) that conveys the untransferred toner collected inside the cleaning device 15 as waste toner toward the waste toner collecting device 30 (see Fig. 3), etc. The cleaning blade 15a is made of a rubber material such as urethane rubber and contacts the surface of the photosensitive drum 11 at a predetermined angle and pressure. Thereby, the deposits such as untransferred toner adhering to the photosensitive drum 11 are mechanically scraped off and collected inside the cleaning device 15. Then, the untransferred toner collected inside the cleaning device 15 is conveyed to the waste toner collecting device 30 via the conveying pipe 16 (inside which the conveying coil 15b is installed) and is collected inside the waste toner collecting device 30 as waste toner from the lower discharge port 35K (see Fig. 3).

[0025] The untransferred toner recovered by the cleaning device 15 of the process cartridge 10K for black is recovered into the waste toner recovery device 30 as waste toner from the lower discharge port 35K for black (see FIG. 3). Further, the untransferred toner recovered by the cleaning device 15 of the process cartridge 10Y for yellow is recovered into the waste toner recovery device 30 as waste toner from the lower discharge port 35Y for yellow (see FIG. 3). Further, the untransferred toner recovered by the cleaning device 15 of the process cartridge 10M for magenta is recovered into the waste toner recovery device 30 as waste toner from the lower discharge port 35M for magenta (see FIG. 3). Further, the untransferred toner recovered by the cleaning device 15 of the process cartridge 10C for cyan is recovered into the waste toner recovery device 30 as waste toner from the lower discharge port 35C for cyan (see FIG. 3).

[0026] Similarly, referring to FIG. 1, the intermediate transfer belt cleaning device 9 as a cleaning device is also provided with a cleaning blade that contacts the intermediate transfer belt 17, a transport coil (transport pipe) that transports the untransferred toner recovered in the intermediate transfer belt cleaning device 9 as waste toner toward the waste toner recovery device 30 (see FIG. 3), and the like. The untransferred toner recovered in the intermediate transfer belt cleaning device 9 is transported to the waste toner recovery device 30 through a transport pipe (in which a transport coil is provided) and is recovered into the waste toner recovery device 30 as waste toner from the upper discharge port 35T for the intermediate transfer belt cleaning device (see FIG. 3). Here, as deposits adhering to the photosensitive drum 11 and the intermediate transfer belt 17, in addition to untransferred toner, there are paper dust generated from the sheet P (paper), discharge products generated on the photosensitive drum 11 during discharge by the charging device 12, additives added to the toner, and the like. In the present application, these are collectively referred to as "untransferred toner". Note that the waste toner recovery device 30 will be described in more detail later.

[0027] In FIG. 2, the imaging process described above will be described in more detail. The developing roller 13a rotates in the direction of the arrow (counterclockwise) in Fig. 2. The developer in the developing device 13 is circulated in the longitudinal direction while being agitated and mixed with the toner replenished from the toner container 28 by a toner replenishing unit (not shown) by the rotation of the first conveying screw 13b1 and the second conveying screw 13b2 disposed with a partition member in between (in the direction perpendicular to the plane of Fig. 2).

[0028] Then, the toner triboelectrically charged and adsorbed to the carrier is carried onto the developing roller 13a together with the carrier. The developer carried on the developing roller 13a then reaches the position of the doctor blade 13c. And the developer on the developing roller 13a is adjusted to an appropriate amount at the position of the doctor blade 13c and then reaches the opposing position (the developing area) with the photosensitive drum 11. Thereafter, in the developing area, the toner in the developer adheres to the electrostatic latent image formed on the surface of the photosensitive drum 11. Specifically, the toner adheres to the latent image (a toner image is formed) by an electric field formed by the potential difference (developing potential) between the latent image potential (exposure potential) of the image area irradiated with the laser beam L and the developing bias applied to the developing roller 13a. Thereafter, most of the toner adhering to the photosensitive drum 11 in the developing process is transferred onto the intermediate transfer belt 17. And the untransferred toner remaining on the photosensitive drum 11 is collected into the cleaning device 15 by the cleaning blade 15a.

[0029] Hereinafter, the waste toner collection device 30 (waste toner collection container), which is characteristic in the image forming apparatus 1 of the present embodiment, will be described in detail. Referring to Fig. 1, in the present embodiment, the waste toner collection device 30 is detachably installed on the side of the intermediate transfer belt 17 and the process cartridge in the image forming apparatus main body 1, on the front side of the image forming apparatus main body 1 (on the front side in the direction perpendicular to the plane of Fig. 1).

[0030] Then, as shown in FIG. 3, in the waste toner recovery device 30 according to the present embodiment, two recovery parts (an upper-stage recovery part A and a lower-stage recovery part B) partitioned by a partition wall 32 are provided inside its exterior case 31. Further, in the waste toner recovery device 30, a communication part (opening part) 33 that communicates with the upper-stage recovery part A and the lower-stage recovery part B is provided at an end in the rotation axis direction (the left-right direction in FIG. 3).

[0031] One upper-stage discharge port 35T (discharge port) is provided in the upper-stage recovery part A. This upper-stage discharge port 35T is a discharge port for carrying the untransferred toner recovered by the intermediate transfer belt cleaning device 9 into the upper-stage recovery part A as waste toner. The lower-stage recovery part B is partitioned from the upper-stage recovery part A by a partition wall 32, and a plurality of lower-stage discharge ports 35Y, 35M, 35C, 35K (four discharge ports) are provided. Specifically, in the lower-stage recovery part B, a plurality of lower-stage discharge ports 35Y, 35M, 35C, 35K are arranged side by side at intervals in the rotation axis direction (the left-right direction in FIG. 3). More specifically, the first lower-stage discharge port 35Y from the left side of the paper surface of FIG. 3 is a discharge port for carrying the untransferred toner recovered by the cleaning device 15 of the yellow process cartridge 10Y into the lower-stage recovery part B as waste toner. Also, the second lower-stage discharge port 35M from the left side of the paper surface of FIG. 3 is a discharge port for carrying the untransferred toner recovered by the cleaning device 15 of the magenta process cartridge 10M into the lower-stage recovery part B as waste toner. Also, the third lower-stage discharge port 35C from the left side of the paper surface of FIG. 3 is a discharge port for carrying the untransferred toner recovered by the cleaning device 15 of the cyan process cartridge 10C into the lower-stage recovery part B as waste toner. Also, the fourth lower-stage discharge port 35K from the left side of the paper surface of FIG. 3 is a discharge port for carrying the untransferred toner recovered by the cleaning device 15 of the black process cartridge 10K into the lower-stage recovery part B as waste toner. The arrangement of these five discharge ports 35T, 35Y, 35M, 35C, and 35K is based on the layout of the intermediate transfer belt cleaning device 9 shown in FIG. 1 and the cleaning devices 15 of the four process cartridges 10Y, 10M, 10C, and 10K.

[0032] In addition, the waste toner collection device 30 in the present embodiment is provided with two conveying members (the upper conveying screw 41 as the upper conveying member and the lower conveying screw 42 as the lower conveying member). The upper conveying screw 41 as the upper conveying member is a conveying member for conveying the waste toner discharged from the upper discharge port 35T in the upper collection portion A toward the communication portion 33 with the rotation axis direction (the direction of the broken line arrow in FIG. 3) as the conveying direction. The lower conveying screw 42 as the lower conveying member is a conveying member for conveying, in the lower collection portion B, the waste toner discharged from the lower discharge ports 35Y, 35M, 35C, and 35K and the waste toner flowing in from the communication portion 33 (the waste toner discharged from the upper discharge port 35T and conveyed by the upper conveying screw 41) in the rotation axis direction toward one end side away from the communication portion 33 (the left side in FIG. 3). That is, in the waste toner collection device 30, the waste toner is conveyed in the direction indicated by the broken line arrow in FIG. 3. Specifically, in the upper collection portion A, the waste toner is conveyed from the left side to the right side in FIG. 3, and at the communication portion 33, the waste toner falls by its own weight from the upper collection portion A to the lower collection portion B, and in the lower collection portion B, the waste toner is conveyed from the right side to the left side in FIG. 3.

[0033] The upper conveying screw 41 (upper conveying member) is a conveying screw in which a screw portion 41b is wound around a shaft portion 41a. The lower conveying screw 42 (lower conveying member) is also a conveying screw in which a screw portion is wound around a shaft portion, similar to the upper conveying screw 41. The upper conveying screw 41 (upper conveying member) is disposed so as to extend in a substantially horizontal direction below the upper discharge port 35T. Further, the lower conveying screw 42 (lower conveying member) is disposed so as to extend in a substantially horizontal direction below the lower discharge ports 35Y, 35M, 35C, and 35K.

[0034] In the present embodiment, a driven coupling 47 (a lower gear 48 is integrally installed) is installed at one end side in the rotation axis direction of the lower conveying screw 42. When the waste toner collection device 30 is set in the image forming apparatus main body 1, the driven coupling 47 is fitted to a driving coupling installed on the motor shaft of a motor 50 (fixed to the apparatus main body 1). Further, the lower gear 48 installed on the lower conveying screw 42 meshes with an upper gear 49 installed on the upper conveying screw 41. With such a configuration, when the motor 50 is driven, the two conveying screws 41 and 42 are rotationally driven in the directions of the arrows in FIG. 3, respectively, enabling the conveyance of the waste toner in the direction of the broken-line arrow described above. In the present embodiment, the upper conveying screw 41 has a region (a low conveying force portion N) in which a screw portion 41b is not formed on the upstream side in the conveying direction (upstream region M), which will be described in detail later.

[0035] As described above, the waste toner collection device 30 in the present embodiment is provided with two collection portions A and B partitioned vertically, and conveys waste toner from the upper collection portion A to the lower collection portion B through the communication portion 33, and conveys the waste toner to the side away from the communication portion 33 in the lower collection portion B. Therefore, as shown in FIG. 4, the waste toner T can be collected with a high collection rate inside the waste toner collection device 30 partitioned into the two collection portions A and B. For example, when no partition is provided between the upper discharge port 35T and the lower discharge ports 35Y, 35M, 35C, and 35K, the waste toner collection device 130 must be replaced (it must be detected as full) before the lower discharge ports 35Y, 35M, 35C, and 35K are blocked by waste toner, resulting in a large useless space where waste toner cannot be collected. Therefore, the cycle for replacing or maintaining the waste toner collection device is shortened. Also, if the two collection parts A and B are completely partitioned by a partition without providing a communication part connecting the upper collection part A and the lower collection part B, even if one collection part is full of waste toner, there is a high possibility that the waste toner collection device must be replaced or maintained while the other collection part is not full. On the other hand, as shown in FIG. 4, the waste toner collection device 30 in the present embodiment can extend the cycle for replacing and maintaining the waste toner collection device because the waste toner T is collected almost evenly inside the waste toner collection device 30 (particularly, the part downstream in the conveyance direction from the uppermost upstream upper discharge port 35T).

[0036] Here, as shown in FIGS. 3 and 4, the waste toner collection device 30 in the present embodiment is provided with a fullness detection sensor 45 as a detection means for detecting that the waste toner T collected in the waste toner collection device 30 is in a full state, and is installed in the lower collection part B. This fullness detection sensor 45 is a detection means for detecting that the waste toner T has reached a predetermined height position above the rotation axis of the lower conveyance screw 42 (lower conveyance member) at one end side in the rotation axis direction (the left side in FIGS. 3 and 4) in the lower collection part B. As such a fullness detection sensor 45, for example, a piezoelectric sensor can be used. When the inside of the waste toner collection device 30 becomes full (or in a state close to full) with the waste toner T (when the fullness detection sensor 45 shown in FIG. 4 detects the state where there is waste toner at that position), this fact is displayed on the display panel of the image forming apparatus 1, and the waste toner collection device 30 is replaced with a new (empty) one. In this embodiment, since the full detection sensor 45 is installed above the lower conveying screw 42 on the downstream side in the conveying direction of the waste toner T in the lower recovery section B, it is possible to prompt the user to replace the waste toner recovery device 130 before the lower discharge ports 35Y, 35M, 35C, and 35K are buried and clogged with waste toner.

[0037] Here, referring to FIGS. 3 and 4, in this embodiment, in the upper recovery section A, a low conveyance capacity section N with a conveyance capacity of the waste toner T in the conveyance direction in the upstream region M from the upstream inner wall section 31a (side wall) located at the upstream end in the conveyance direction (the left end in FIGS. 3 and 4) to the upper discharge port 35T (one upper discharge port) is lower than the conveyance capacity in the region (downstream region V) on the downstream side of the upstream region M is formed. Note that the "conveyance capacity" in the conveyance direction for the waste toner T is synonymous with the amount (conveyance amount) of the waste toner T that can be conveyed in the conveyance direction per unit time.

[0038] Specifically, the upper conveying screw 41 (upper conveying member) in this embodiment includes a shaft portion 41a extending from the upstream inner wall portion 31a to the downstream inner wall portion 31b, and a screw portion 41b wound around a region of the shaft portion 41a excluding the low conveyance capacity portion N (a region downstream of the low conveyance capacity portion N). It is a conveying screw. That is, in the upper conveying screw 41 in this embodiment, the screw portion 41b is not formed in the low conveyance capacity portion N, and it is configured such that the waste toner T cannot be actively conveyed in the low conveyance capacity portion N. Note that the downstream inner wall portion 31b is a side wall located at the downstream end in the conveyance direction in the upper recovery section A (the right end in FIGS. 3 and 4).

[0039] By providing the low conveyance capacity portion N in the upstream region M in this way, it is possible to reduce the problem that a useless space where the waste toner T cannot be sufficiently recovered is generated in the upstream region M on the upstream side in the conveyance direction in the upper recovery section A. Specifically, as in the waste toner collection device 130 shown in FIG. 5 as Comparative Example 1, if the upper conveying screw 141 with a screw part formed over the entire width direction is used, the waste toner T will be actively conveyed downstream by the upper conveying screw 141 even in the upstream region M, so that a large useless space (the space indicated by the broken line, which is a dead space) where the waste toner T cannot be recovered will be generated in the upstream region M. As a result, the cycle for replacing or maintaining the waste toner collection device 130 will be shortened. On the other hand, as shown in FIG. 4, in the waste toner collection device 30 of the present embodiment, since the waste toner T is recovered almost evenly throughout the waste toner collection device 30 including the upstream region M, the cycle for replacing or maintaining the waste toner collection device can be extended.

[0040] Here, as shown in FIGS. 3 and 4, in the present embodiment, the low conveyance capacity part N is formed upstream of the midpoint of the upstream region M in the upstream region M. That is, the low conveyance capacity part N is not provided over the entire upstream region M, but is provided within the upstream half region (M / 2) thereof (in the examples of FIGS. 3 and 4, it is the range from the upstream inner wall part 31a to approximately the midpoint). Specifically, the screw part 41b of the upper conveying screw 41 is formed up to approximately the midpoint in the upstream region M. The reason for configuring like this is that, as in the waste toner collection device 230 shown in FIG. 6 as Comparative Example 2, if an upper conveying screw 241 with a region where the screw part 41b is not formed (in the example of FIG. 6, it is upstream of the vicinity of the upper discharge port 35T) being too wide is used, the waste toner T will stay early in the upstream region M and accumulate less, and there will easily occur a problem that the upper discharge port 35T will be blocked by the waste toner T before the waste toner collection device 230 is filled with the waste toner T. Therefore, as shown in FIGS. 3 and 4, in the present embodiment, by slightly extending the screw part 41b of the upper conveying screw 41 to a range upstream of the upper discharge port 35T, the problem that the waste toner T stays early in the upstream region M is suppressed.

[0041] <Modification Example 1> As shown in FIG. 7, in the waste toner recovery device 30 in Modification Example 1, the upper-stage conveying screw 41 (upper-stage conveying member) includes a shaft portion 41a extending from the upstream inner wall portion 31a to the downstream inner wall portion 31b, a first screw portion 41b1 wound around a region (downstream region V) excluding the upstream region M on the shaft portion 41a, and a second screw portion 41b2 wound around the upstream region M on the shaft portion 41a in a direction opposite to that of the first screw portion 41b1. Therefore, the upper-stage conveying screw 41 in Modification Example 1 is configured to actively convey the waste toner T toward the downstream side (communication portion 33) in the downstream region V on the downstream side with the upper-stage discharge port 35T as a boundary, and to actively convey the waste toner T toward the upstream side (upstream inner wall portion 31a) in the upstream region M on the upstream side. In this way, the configuration of actively conveying the waste toner T toward the upstream side (upstream inner wall portion 31a) is also a low-conveying-capability portion N where the conveying capability of the waste toner T in the conveying direction (the conveying direction toward the communication portion 33) is lower than that in the region (downstream region V) on the downstream side of the upstream region M. With such a configuration, the waste toner T is actively recovered also in the upstream region M by the conveyance of the waste toner by the second screw portion 41b2, and the waste toner is almost completely recovered without waste in the waste toner recovery device 30 including the upstream region M of the upper-stage recovery portion A.

[0042] <Modification Example 2> As shown in FIG. 8, in the waste toner recovery device 30 in Modification Example 2, the upper-stage conveying screw 41 (upper-stage conveying member) includes a shaft portion 41a extending from the upstream inner wall portion 31a to the downstream inner wall portion 31b, a first screw portion 41b1 wound around a region (downstream region V) excluding the upstream region M on the shaft portion 41a, and a second screw portion 41b2 wound around the upstream region M on the shaft portion 41a with a screw width t2 (<t1) thinner than the screw width t1 (the thickness of the screw portion) of the first screw portion 41b1. When the screw width becomes thinner, the conveying capacity for the waste toner T tends to be smaller than when the screw width is thick. Therefore, in the upper conveying screw 41 in the second modification, the conveying capacity in the upstream region M on the upstream side is lower than the conveying capacity in the downstream region V on the downstream side with the upper discharge port 35T as the boundary. That is, in the second modification, almost the entire upstream region M becomes a low-conveying-capacity portion. Even in such a configuration, since the upstream region M becomes a low-conveying-capacity portion and the waste toner recovery performance in the upstream region M is improved compared to the waste toner recovery device 130 described as Comparative Example 1 in FIG. 5 above, the waste toner is almost entirely recovered without waste in the waste toner recovery device 30 including the upstream region M of the upper recovery portion A. In the second modification, when it is desired to further weaken the conveying capacity of the upper conveying screw 41 in the upstream region M, it can also be configured not to form the second screw portion 41b2 in the range N described above with reference to FIGS. 3 and the like.

[0043] <Modification 3> As shown in FIG. 9, in the waste toner recovery device 30 in the third modification, the upper conveying screw 41 (upper conveying member) includes a shaft portion 41a extending from the upstream inner wall portion 31a to the downstream inner wall portion 31b, a first screw portion 41b1 wound around the shaft portion 41a in a region (downstream region V) excluding the upstream region M, and a second screw portion 41b2 wound around the shaft portion 41a in the upstream region M with a screw diameter D2 (<D1) smaller than the screw diameter D1 (the outer diameter of the screw portion). When the screw diameter becomes smaller, the conveying capacity for the waste toner T becomes smaller than when the screw diameter is large. Therefore, in the upper conveying screw 41 in the third modification, the conveying capacity in the upstream region M on the upstream side is lower than the conveying capacity in the downstream region V on the downstream side with the upper discharge port 35T as the boundary. That is, in the third modification, almost the entire upstream region M becomes a low-conveying-capacity portion. Even when configured in this way, since the upstream region M becomes a low-conveying-capacity portion and the waste toner recovery property in the upstream region M is improved compared to the waste toner recovery device 130 described as Comparative Example 1 with reference to FIG. 5 above, waste toner is almost entirely recovered without waste in the waste toner recovery device 30 including the upstream region M of the upper-stage recovery portion A. In addition, in Modification 3, when it is desired to further weaken the conveying capacity of the upper-stage conveying screw 41 in the upstream region M, it is also possible to configure such that the second screw portion 41b2 is not formed in the range N described above with reference to FIGS. 3 and the like.

[0044] <Modification 4> As shown in FIG. 10, in the waste toner recovery device 30 in Modification 3, the upper-stage conveying screw 41 (upper-stage conveying member) includes a shaft portion 41a extending from the upstream inner wall portion 31a to the downstream inner wall portion 31b, a first screw portion 41b1 wound around a region (downstream region V) excluding the upstream region M on the shaft portion 41a, and a second screw portion 41b2 wound around the upstream region M on the shaft portion 41a with a screw pitch W2 (>W1) longer than the screw pitch W1 (the interval in the rotational axis direction between adjacent screws) of the first screw portion 41b1. When the screw pitch becomes longer, the conveying capacity for the waste toner T becomes smaller compared to the case where the screw pitch is short. Therefore, the upper-stage conveying screw 41 in Modification 4 has a lower conveying capacity in the upstream region M on the upstream side compared to the conveying capacity in the downstream region V on the downstream side with the upper-stage discharge port 35T as a boundary. That is, in Modification 4, almost the entire upstream region M becomes a low-conveying-capacity portion. Even when configured in this way, since the upstream region M becomes a low-conveying-capacity portion and the waste toner recovery property in the upstream region M is improved compared to the waste toner recovery device 130 described as Comparative Example 1 with reference to FIG. 5 above, waste toner is almost entirely recovered without waste in the waste toner recovery device 30 including the upstream region M of the upper-stage recovery portion A. In addition, in Modification 4, when it is desired to further weaken the conveying capacity of the upper conveying screw 41 in the upstream region M, it is also possible to configure the device so that the second screw portion 41b2 is not formed in the range N described above with reference to FIG. 3 and the like.

[0045] <Modification 5> As shown in FIG. 11, in the waste toner collection device 30 in Modification 5, the upstream region M is configured such that the cross-sectional area (cross-sectional area) of a cross-section orthogonal to the rotation axis direction is larger than the cross-sectional area (cross-sectional area) of the cross-section in the downstream region (downstream region V). Specifically, the partition wall 32 that separates the upper collection portion A and the lower collection portion B is formed to incline upward from the upstream inner wall portion 31a toward the downstream inner wall portion 31b. That is, the bottom surface in the upper collection portion A inclines upward from the left side (upstream side) to the right side (downstream side) in FIG. 11, and is configured such that the cross-sectional area gradually decreases. In other words, the upper collection portion A is configured such that the height from the bottom surface to the ceiling surface gradually decreases from the upstream side to the downstream side. Further, the upper conveying screw 41 has a screw portion 41b formed over the rotation axis direction, and is installed such that the shaft portion 41a is substantially parallel to the inclination of the partition wall 32. By configuring in this way, it is possible to increase the space capable of storing the waste toner T in the upstream side (particularly, the upstream region M), and it becomes possible to increase the amount of waste toner collected. In particular, when the amount of waste toner input from the upper discharge port 35T is large, etc., the collection efficiency (amount of waste toner collected) in the waste toner collection device 30 can be enhanced. Also, when configured in this way, the amount of waste toner per unit length staying in the upstream region M is increased compared to the downstream region V, and a low conveying capacity portion is formed in the upstream region M. Therefore, from this viewpoint as well, the waste toner recoverability in the upstream region M is improved, and the waste toner is almost entirely recovered without waste in the waste toner collection device 30 including the upstream region M of the upper collection portion A. In addition, in Modification 5, when it is desired to further weaken the conveying capacity of the upper conveying screw 41 in the upstream region M, it is also possible to configure so as not to form the second screw portion 41b2 in the range N described above with reference to FIG. 3 etc. Also, in the example of FIG. 11, the partition wall 32 is inclined so that the cross-sectional area of the upstream region M is larger than that of the downstream region V. However, the method of providing a difference in the cross-sectional area is not limited to this. For example, by providing a recess in the inner wall portion of the upstream region M, the cross-sectional area of the upstream region M can be made larger than that of the downstream region V.

[0046] <Modification 6> As shown in FIG. 12, in the waste toner collection device 30 in Modification 6, the upper conveying screw 41 (upper conveying member) is provided with a stirring member that rotates together with the upper conveying screw 41 in the upstream region M and stirs the waste toner T staying in the upstream region M. Specifically, on the shaft portion 41a of the upper conveying screw 41 shown in FIG. 12(A), a paddle portion 41c in the shape of a substantially rectangular plate is installed as a stirring member at a position close to the upstream inner wall portion 31a in the upstream region M. On the other hand, on the shaft portion 41a of the upper conveying screw 41 shown in FIG. 12(B), an agitator portion 41d formed by bending a round bar-shaped member into a substantially U shape is installed as a stirring member in the upstream region M. In this way, by providing a stirring member such as the paddle portion 41c or the agitator portion 41d at a position corresponding to the upstream region M in the upper conveying screw 41, even if a large amount of waste toner T is collected and likely to aggregate in the upstream region M, the aggregation of the waste toner T is suppressed by the stirring by the stirring member. Note that the configuration of providing the stirring member on the upper conveying screw 41 in this way is not limited to the example of FIG. 12, and can be configured in combination with the upper conveying screw 41 in any of FIGS. 3, 7 to 11.

[0047] As described above, the waste toner collection device 30 in the present embodiment includes an upper collection part A having one (or a plurality of) upper discharge ports 35T, and a lower collection part B which is partitioned from the upper collection part A by a partition wall 32 and has a plurality (or one) of lower discharge ports 35Y, 35M, 35C, 35K, and a communication part 33 that communicates the upper collection part A and the lower collection part B are provided. Further, in the upper collection part A, an upper conveyance screw 41 (upper conveyance member) is provided that conveys the waste toner discharged from the upper discharge port 35T in the direction of the rotation axis toward the communication part 33 with the direction of the rotation axis as the conveyance direction. Furthermore, in the lower collection part B, a lower conveyance screw 42 (lower conveyance member) is provided that conveys the waste toner discharged from the lower discharge ports 35Y, 35M, 35C, 35K and the waste toner flowing in from the communication part 33 in the direction of the rotation axis toward one end side in the direction of the rotation axis away from the communication part 33. And, in the upper collection part A, in the upstream region M from the upstream inner wall part 31a located at the upstream end part in the conveyance direction to one upper discharge port 35T (or the upper discharge port located most upstream among the plurality of upper discharge ports), a low conveyance capacity part N is formed in which the conveyance capacity of the waste toner T in the conveyance direction is lower than the conveyance capacity in the region V on the downstream side of the upstream region M. Thereby, including the upstream region M of the upper collection part A in the waste toner collection device 30 partitioned into two collection parts A and B, the waste toner can be recovered almost without waste as a whole.

[0048] In the present embodiment, the present invention is applied to the waste toner collection device 30 in which one upper discharge port 35T is provided in the upper collection part A and a plurality (four) of lower discharge ports 35Y, 35M, 35C, 35K are provided in the lower collection part B. However, the application of the present invention is not limited to this. For example, the present invention can naturally be applied to a waste toner collection device in which a plurality of upper discharge ports are provided in the upper collection part, a waste toner collection device in which one lower discharge port is provided in the lower collection part, and the like. In particular, in the case of a waste toner collection device in which a plurality of upper discharge ports are provided in the upper collection part, from the upstream inner wall part 31a to the upper discharge port located most upstream among the plurality of upper discharge ports (the upper discharge port closest to the upstream inner wall part 31a), is the upstream region M. In addition, in the present embodiment, the upper discharge port 35T is formed on the vertical wall surface of the upper recovery section A. However, the upper discharge port 35T can also be formed on the ceiling surface of the upper recovery section A. In that case, the untransferred toner recovered by the intermediate transfer belt cleaning device 9 will fall by its own weight in the direction of the arrow from the upper discharge port 35T formed on the ceiling surface of the upper recovery section A (waste toner recovery device 30) and will be carried into the upper recovery section A as waste toner. And even in such cases, the same effects as those of the present embodiment can be obtained.

[0049] It should be noted that the present invention is not limited to the present embodiment. It is obvious that within the scope of the technical idea of the present invention, the present embodiment can be appropriately modified in addition to what is suggested in the present embodiment. Also, the number, position, shape, etc. of the above-described constituent members are not limited to the present embodiment and can be set to appropriate numbers, positions, shapes, etc. for implementing the present invention.

Explanation of Reference Numerals

[0050] 1 Image forming apparatus (image forming apparatus main body), 9 Intermediate transfer belt cleaning device, 11 Photoconductor drum (image carrier), 15 Cleaning device (photoconductor drum cleaning device), 17 Intermediate transfer belt (image carrier, intermediate transfer member), 30 Waste toner recovery device (waste toner recovery container), 31 Exterior case, 31a Upstream inner wall portion, 31b Downstream inner wall portion, 32 Partition wall (partition member), 33 Communication portion (opening), 35T Upper discharge port, 35Y, 35M, 35C, 35K Lower discharge ports, 41 Upper conveyance screw (upper conveyance member, conveyance screw), 41a Shaft portion, 41b Screw portion, 41b1 First screw portion, 41b2 Second screw portion, 41c Paddle portion (agitation member), 41d agitator section (agitating member), 42 lower conveying screw (lower conveying member), 45 full cup detection sensor (detection means), A upper recovery section, B lower recovery section, M upstream region, N low conveying capacity section, V downstream region.

[0051] In addition, the embodiments in the present invention can also be, for example, combinations of the following Supplementary Notes 1 to 11. (Supplementary Note 1) An upper recovery section having one or more upper discharge ports, A lower recovery section partitioned by a partition wall with respect to the upper recovery section and having one or more lower discharge ports, A communication section communicating with the upper recovery section and the lower recovery section, In the upper recovery section, an upper conveying member that conveys the waste toner discharged from the upper discharge port in the direction of the rotation axis with the direction of the rotation axis as the conveying direction toward the communication section, In the lower recovery section, a lower conveying member that conveys the waste toner discharged from the lower discharge port and the waste toner flowing in from the communication section in the direction of the rotation axis toward one end side in the direction of the rotation axis away from the communication section, Comprising, The upper recovery section has a low conveying capacity section in the upstream region from the upstream inner wall section located at the upstream end in the conveying direction to the one upper discharge port or the upper discharge port located most upstream among the plurality of upper discharge ports, where the conveying capacity of the waste toner in the conveying direction is lower than the conveying capacity in the region downstream of the upstream region. The waste toner recovery device is characterized by this. (Supplementary Note 2) The waste toner recovery device according to Supplementary Note 1, wherein the low conveying capacity section is formed upstream of the midpoint of the upstream region in the upstream region. (Supplementary Note 3) The upper-stage conveying member is a conveying screw including a shaft portion extending from the upstream-side inner wall portion to the downstream-side inner wall portion, and a screw portion wound around a region of the shaft portion excluding the low-conveying-capability portion, and is characterized by the waste toner collection device according to appended claim 1 or appended claim 2. (Appended claim 4) The upper-stage conveying member is a conveying screw including a shaft portion extending from the upstream-side inner wall portion to the downstream-side inner wall portion, a first screw portion wound around a region of the shaft portion excluding the upstream-side region, and a second screw portion wound around the upstream-side region of the shaft portion in a direction opposite to that of the first screw portion, and is characterized by the waste toner collection device according to any one of appended claims 1 to 3. (Appended claim 5) The upper-stage conveying member is a conveying screw including a shaft portion extending from the upstream-side inner wall portion to the downstream-side inner wall portion, a first screw portion wound around a region of the shaft portion excluding the upstream-side region, and a second screw portion wound around the upstream-side region of the shaft portion with a screw width thinner than the screw width of the first screw portion, and is characterized by the waste toner collection device according to any one of appended claims 1 to 4. (Appended claim 6) The upper-stage conveying member is a conveying screw including a shaft portion extending from the upstream-side inner wall portion to the downstream-side inner wall portion, a first screw portion wound around a region of the shaft portion excluding the upstream-side region, and a second screw portion wound around the upstream-side region of the shaft portion with a screw diameter smaller than the screw diameter of the first screw portion, and is characterized by the waste toner collection device according to any one of appended claims 1 to 5. (Appended claim 7) The upper-stage conveying member is a conveying screw including a shaft portion extending from the upstream-side inner wall portion to the downstream-side inner wall portion, a first screw portion wound around a region of the shaft portion excluding the upstream-side region, and a second screw portion wound around the upstream-side region of the shaft portion with a screw pitch longer than the screw pitch of the first screw portion, and is characterized by the waste toner collection device according to any one of appended claims 1 to 6. (Appended claim 8) The upstream region is characterized in that the area of the cross-section orthogonal to the rotation axis direction is larger than the area of the cross-section in the downstream region, and the waste toner collection device according to any one of Appendices 1 to 7. (Appendix 9) The partition wall is characterized in that it inclines upward from the upstream inner wall portion toward the downstream inner wall portion, and the waste toner collection device according to any one of Appendices 1 to 8. (Appendix 10) The upper-stage conveying member is characterized in that in the upstream region, it is provided with a stirring member that rotates together with the upper-stage conveying member and stirs the waste toner staying in the upstream region, and the waste toner collection device according to any one of Appendices 1 to 9. (Appendix 11) An image forming apparatus characterized by including the waste toner collection device according to any one of Appendices 1 to 10.

Prior Art Documents

Patent Documents

[0052]

Patent Document 1

Claims

1. an upper recovery section having one or more upper discharge ports; a lower recovery section partitioned from the upper recovery section by a partition wall and having one or more lower discharge ports; a communication section communicating with the upper recovery section and the lower recovery section; in the upper recovery section, an upper transport member that transports waste toner discharged from the upper discharge port in the direction of the rotation axis with the direction of the rotation axis as the transport direction toward the communication section; in the lower recovery section, a lower transport member that transports waste toner discharged from the lower discharge port and waste toner flowing in from the communication section in the direction of the rotation axis toward one end side in the direction of the rotation axis away from the communication section; comprising; the upper recovery section has a low transport capacity section in an upstream region from an upstream inner wall section located at an upstream end portion in the transport direction to the one upper discharge port or the upper discharge port located most upstream among the plurality of upper discharge ports, where the transport capacity of the waste toner in the transport direction is lower than that in a region downstream of the upstream region. A waste toner recovery device characterized by this.

2. The waste toner recovery device according to claim 1, wherein the low transport capacity section is formed upstream of a midpoint of the upstream region in the upstream region.

3. The waste toner recovery device according to claim 2, wherein the upper transport member is a transport screw including a shaft portion extending from the upstream inner wall section to a downstream inner wall section and a screw portion wound around a region of the shaft portion excluding the low transport capacity section.

4. The waste toner recovery device according to claim 1 or claim 2, wherein the upper transport member is a transport screw including a shaft portion extending from the upstream inner wall section to a downstream inner wall section, a first screw portion wound around a region of the shaft portion excluding the upstream region, and a second screw portion wound around the upstream region of the shaft portion in a direction opposite to that of the first screw portion.

5. The waste toner recovery device according to claim 1 or claim 2, wherein the upper transport member is a transport screw including a shaft portion extending from the upstream inner wall section to a downstream inner wall section, a first screw portion wound around a region of the shaft portion excluding the upstream region, and a second screw portion wound around the upstream region of the shaft portion with a screw width thinner than that of the first screw portion.

6. The upper-stage conveying member is a conveying screw comprising a shaft portion extending from the upstream-side inner wall portion to the downstream-side inner wall portion, a first screw portion wound around a region of the shaft portion excluding the upstream-side region, and a second screw portion wound around the upstream-side region of the shaft portion with a screw diameter smaller than that of the first screw portion. The waste toner collection device according to claim 1 or claim 2 is characterized by this.

7. The upper-stage conveying member is a conveying screw comprising a shaft portion extending from the upstream-side inner wall portion to the downstream-side inner wall portion, a first screw portion wound around a region of the shaft portion excluding the upstream-side region, and a second screw portion wound around the upstream-side region of the shaft portion with a screw pitch longer than that of the first screw portion. The waste toner collection device according to claim 1 or claim 2 is characterized by this.

8. The upstream-side region is characterized in that the area of a cross-section orthogonal to the rotation axis direction is larger than the area of the cross-section in the downstream-side region. The waste toner collection device according to claim 1 or claim 2 is characterized by this.

9. The partition wall is inclined upward from the upstream-side inner wall portion toward the downstream-side inner wall portion. The waste toner collection device according to claim 1 or claim 2 is characterized by this.

10. The upper-stage conveying member is characterized in that it is provided with a stirring member that rotates together with the upper-stage conveying member in the upstream-side region and stirs the waste toner staying in the upstream-side region. The waste toner collection device according to claim 1 or claim 2 is characterized by this.

11. An image forming apparatus characterized by comprising the waste toner collection device according to claim 1 or claim 2.

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