JP2017198896A - Cleaning device and image forming apparatus including the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a cleaning device that can suppress a contact part of a sealing member and a recovery roller from being clogged with toner and paper powder while suppressing a reduction in sealability of the sealing member, and an image forming apparatus including the same.SOLUTION: A belt cleaning unit (cleaning device) 19 comprises: a housing 40 that has a waste toner storage part 40b formed therein; a recovery roller 43 that recovers a waste toner; a cleaning blade 45; and a sealing member 50 that is arranged in contact with the recovery roller 43 and suppresses backflow of the waste toner from the waste toner storage part 40b to an opening part 40a. The recovery roller 43 has the minimum radius Rmin in which the distance from the center of rotation O to an outer peripheral surface is smallest and the maximum radius Rmax in which the distance from the center of rotation O to the outer peripheral surface is largest.SELECTED DRAWING: Figure 3

Description

  The present invention relates to a cleaning device and an image forming apparatus including the same, and more particularly to a cleaning member that removes residual toner on the surface of an image carrier, a recovery roller that recovers waste toner attached to the cleaning member, and a recovery roller. The present invention relates to a cleaning device including a sealing member in contact therewith and an image forming apparatus including the same.

  In an image forming apparatus using an electrophotographic method such as a copying machine, a printer, or a facsimile, a powder developer is mainly used, and an electrostatic latent image formed on an image carrier such as a photosensitive drum using the developing apparatus. A general process is to make an image visible, transfer the visible image (toner image) onto a recording medium, and perform a fixing process. The toner remaining on the surface of the image carrier is removed by a cleaning device, and a new toner image is formed.

  The cleaning device includes a fur brush (cleaning member) that removes toner from the surface of the image carrier, a recovery roller that recovers toner from the fur brush, a cleaning blade that scrapes off toner on the surface of the recovery roller, and a recovery roller. Some have a discharge screw that discharges toner scraped off from the surface to the outside, and a seal member that partitions the inside of the housing into a collection roller side and a discharge screw side.

  A cleaning device including a fur brush that removes toner from the surface of an image carrier, a collection roller that collects waste toner attached to the fur brush, and a seal member that contacts the collection roller is disclosed in, for example, Patent Document 1. It is disclosed.

JP 2012-203331 A

  By the way, in the cleaning device, the seal member needs to contact the collecting roller with a contact pressure that does not allow the waste toner scraped off by the cleaning blade to leak to the outside (image carrier side). At this time, in order to satisfy the sealing function in the entire longitudinal direction of the sealing member, it is necessary to ensure a certain contact pressure. On the other hand, when the seal member is strongly applied to the collection roller, the toner and paper powder on the surface of the collection roller are dammed up and then dropped. When the toner or paper dust that has fallen is collected until it contacts the fur brush, the toner or paper dust is conveyed to the image carrier through the fur brush, causing an image defect.

  The present invention has been made in order to solve the above-described problems, and an object of the present invention is to provide a contact portion between the seal member and the collection roller while suppressing deterioration of the sealing performance of the seal member. It is an object of the present invention to provide a cleaning device capable of suppressing clogging of toner and paper dust and an image forming apparatus including the same.

  In order to achieve the above object, a cleaning device according to a first configuration of the present invention includes an opening facing the image carrier, a waste toner container that stores toner scraped from the surface of the image carrier, , A cleaning member that is disposed near the opening of the housing and scrapes residual toner on the surface of the image carrier, a rotatable recovery roller that recovers waste toner attached to the cleaning member, and a recovery roller A cleaning blade that scrapes off the waste toner on the surface of the sheet, and a sheet-like sheet that is disposed in contact with the collection roller so as to extend in the longitudinal direction of the collection roller, and suppresses the backflow of the waste toner from the waste toner container to the opening side. A seal member. The collection roller has a minimum radius having the smallest distance from the rotation center to the outer peripheral surface and a maximum radius having the largest distance from the rotation center to the outer peripheral surface.

  According to the first configuration of the present invention, the collection roller has a minimum radius having the smallest distance from the rotation center to the outer peripheral surface and a maximum radius having the largest distance from the rotation center to the outer peripheral surface. As a result, when the collection roller rotates, the toner or paper powder at the contact portion (seal portion) between the seal member and the collection roller can be pushed into the waste toner storage portion by the large diameter portion. For this reason, it is possible to suppress the toner and paper dust from being clogged and falling at the seal portion, and thus it is possible to prevent the toner and paper dust from being conveyed to the image carrier via the cleaning member and causing image defects. be able to.

  In addition, since it is not necessary to reduce the contact pressure of the seal member with respect to the recovery roller in order to suppress clogging of toner and paper dust at the seal portion, it is possible to suppress deterioration of the sealing performance of the seal member with respect to the recovery roller. it can.

1 is a schematic diagram illustrating a structure of an image forming apparatus including a belt cleaning unit (cleaning apparatus) according to an embodiment of the present invention. FIG. 2 is an enlarged view of the vicinity of an image forming unit Pa in FIG. 1. It is side surface sectional drawing which shows the internal structure of the belt cleaning unit of one Embodiment of this invention. It is the figure which showed the structure of the collection | recovery roller of the belt cleaning unit of one Embodiment of this invention. It is the figure which showed the structure of the collection | recovery roller and sealing member of the belt cleaning unit of one Embodiment of this invention, and the figure which showed the state in which the small diameter part of the collection | recovery roller is contacting the sealing member. It is the figure which showed the structure of the collection | recovery roller and seal member of the belt cleaning unit of one Embodiment of this invention, and is the figure which showed the intermediate state of FIG. 5 and FIG. It is the figure which showed the structure of the collection | recovery roller and sealing member of the belt cleaning unit of one Embodiment of this invention, and was the figure which showed the state which the large diameter part of the collection | recovery roller is contacting the sealing member.

  Embodiments of the present invention will be described below with reference to the drawings.

  FIG. 1 is a schematic diagram showing a configuration of an image forming apparatus 100 including a belt cleaning unit 19 that is a cleaning apparatus according to an embodiment of the present invention. FIG. 2 is an enlarged view of the vicinity of an image forming unit Pa in FIG. It is.

  The image forming apparatus 100 of FIG. 1 has the following configuration. In the main body of the image forming apparatus 100, four image forming portions Pa, Pb, Pc, and Pd are sequentially arranged from the upstream side in the transport direction (the right side in FIG. 1). These image forming portions Pa to Pd are provided corresponding to images of four different colors (cyan, magenta, yellow, and black), and cyan, magenta, and yellow are respectively performed by charging, exposure, development, and transfer processes. And a black image are sequentially formed.

  These image forming portions Pa to Pd are provided with photosensitive drums 1a, 1b, 1c and 1d which carry visible images (toner images) of the respective colors, and are further illustrated by a driving means (not shown). In FIG. 1, an intermediate transfer belt (image carrier) 8 that rotates in the clockwise direction is provided adjacent to each of the image forming portions Pa to Pd.

  The transfer paper P onto which the toner image is transferred is accommodated in a paper cassette 16 at the lower part of the main body of the image forming apparatus 100, and is conveyed to the secondary transfer roller 9 via the paper feed roller 12a and the registration roller pair 12b. .

  Next, the image forming units Pa to Pd will be described. Around and below the photosensitive drums 1a to 1d arranged to be rotatable, chargers 2a, 2b, 2c and 2d for charging the photosensitive drums 1a to 1d, and image information to each of the photosensitive drums 1a to 1d. The exposure unit 4 for exposing the toner, the developing units 3a, 3b, 3c and 3d for forming toner images on the photosensitive drums 1a to 1d, and the developer (toner) remaining on the photosensitive drums 1a to 1d are removed. Cleaning devices 5a, 5b, 5c and 5d are provided.

  Hereinafter, the image forming unit Pa will be described in detail with reference to FIG. 2. However, the image forming units Pb to Pd have basically the same configuration, and thus description thereof is omitted. As shown in FIG. 2, a charger 2a, a developing unit 3a, and a cleaning device 5a are disposed around the photosensitive drum 1a along the drum rotation direction (counterclockwise direction in FIG. 1). A primary transfer roller 6 a is disposed with 8 interposed therebetween. Further, a belt cleaning unit 19 facing the tension roller 11 with the intermediate transfer belt 8 interposed therebetween is disposed on the upstream side in the rotation direction of the intermediate transfer belt 8 with respect to the photosensitive drum 1a. The detailed configuration of the belt cleaning unit 19 will be described later.

  The cleaning device 5 a includes a rubbing roller 27, a drum cleaning blade 28, and a collection screw 29. Residual toner removed from the surface of the photosensitive drum 1 a by the rubbing roller 27 and the drum cleaning blade 28 is discharged to the outside of the cleaning device 5 a as the recovery screw 29 rotates, and is conveyed to a toner recovery container (not shown). And stored.

  Next, an image forming procedure in the image forming apparatus 100 will be described. When the start of image formation is input by the user, first, the surfaces of the photosensitive drums 1a to 1d are uniformly charged by the chargers 2a to 2d. Next, the exposure unit 4 irradiates the surfaces of the photosensitive drums 1a to 1d to form electrostatic latent images corresponding to the image signals on the photosensitive drums 1a to 1d. Each of the developing units 3a to 3d is filled with a predetermined amount of cyan, magenta, yellow, and black toner by a replenishing device (not shown). The toner is supplied onto the photosensitive drums 1a to 1d by the developing units 3a to 3d and electrostatically attached, whereby a toner image corresponding to the electrostatic latent image formed by exposure from the exposure unit 4 is formed. It is formed.

  The primary transfer rollers 6a to 6d apply an electric field at a predetermined transfer voltage between the primary transfer rollers 6a to 6d and the photosensitive drums 1a to 1d, and cyan, magenta, yellow, and yellow on the photosensitive drums 1a to 1d. A black toner image is primarily transferred onto the intermediate transfer belt 8. These four color images are formed with a predetermined positional relationship predetermined for forming a predetermined full-color image. Thereafter, the toner remaining on the surfaces of the photosensitive drums 1a to 1d is removed by the cleaning devices 5a to 5d in preparation for the subsequent formation of a new electrostatic latent image.

  When the intermediate transfer belt 8 starts to rotate clockwise as the drive roller 10 is rotated by a drive motor (not shown), the transfer paper P is provided adjacent to the intermediate transfer belt 8 from the registration roller 12b at a predetermined timing. The full-color image is transferred to the secondary transfer roller 9 thus transferred. The transfer paper P onto which the toner image is transferred is conveyed to the fixing unit 7. The toner remaining on the surface of the intermediate transfer belt 8 is removed by the belt cleaning unit 19.

  The transfer paper P conveyed to the fixing unit 7 is heated and pressed by a pair of fixing rollers, and the toner image is fixed on the surface of the transfer paper P, thereby forming a predetermined full-color image. The transfer paper P on which the full-color image is formed is distributed in the transport direction by the branching section 14 and is discharged to the discharge tray 17 by the discharge roller 15 as it is (or after being sent to the double-sided conveyance path 18 and printed on both sides). The

  Next, the structure of the belt cleaning unit 19 will be described.

  As shown in FIG. 3, the belt cleaning unit 19 includes a fur brush (cleaning member) 41, a collection roller 43, a cleaning blade 45, and a discharge screw 47 in a housing 40. A drive input gear train (not shown) for inputting a drive force to 41, the collection roller 43, and the discharge screw 47 is disposed. FIG. 3 shows a state viewed from the back side in FIG.

  The fur brush 41 is configured by winding a fiber made of an insulating resin such as acrylic or rayon and having conductivity with carbon or the like around a shaft made of SUS or the like. The fur brush 41 is disposed opposite to the tension roller 11 via the intermediate transfer belt 8 on the opening 40 a side of the housing 40. The fur brush 41 rotates in a counter direction (counterclockwise direction in FIG. 3) with respect to the moving direction of the intermediate transfer belt 8, thereby causing foreign matter such as toner or paper dust remaining on the intermediate transfer belt 8 (hereinafter referred to as toner). Etc.). The scraped toner or the like adheres to the brush portion of the fur brush 41.

  The collection roller 43 is constituted by a shaft made of SUS or the like, or a shaft having a resistance layer such as anodized on the surface. The collection roller 43 rotates in the opposite direction (clockwise direction in FIG. 3) to the fur brush 41 while being in contact with the surface of the fur brush 41, and a bias having a polarity opposite to that of the toner is applied to the fur brush 41. Collect the adhered toner. The detailed structure of the collection roller 43 will be described later.

  The cleaning blade 45 is fixed to a holding member 48 made of sheet metal, and comes into contact with the collection roller 43 from the downstream side with respect to the rotation direction of the collection roller 43 (counter direction with respect to the moving direction of the surface of the collection roller 43). The collecting roller 43 is cleaned by scraping off the toner collected by the above. Further, the holding member 48 is urged toward the collection roller 43 (lower right in FIG. 3) by an urging member 49 made of a coil spring or the like. The holding member 48 may be directly fixed to the housing 40 (without the biasing member 49).

  The discharge screw 47 is disposed in the waste toner container 40 b of the housing 40. The discharge screw 47 is constituted by a rotation shaft 47a extending in the longitudinal direction of the collection roller 43 (perpendicular to the paper surface of FIG. 3) and a spiral blade 47b provided on the peripheral surface of the rotation shaft 47a. The discharge screw 47 rotates in the clockwise direction of FIG. 3, thereby transporting the toner scraped off from the collection roller 43 by the cleaning blade 45 in the axial direction of the rotation shaft 47 a and discharging it to the outside of the housing 40.

  Inside the housing 40, a seal member 50 that is in contact with the entire length of the collection roller 43 is disposed so as to extend in the length direction of the collection roller 43. The seal member 50 is a sheet-like member formed of, for example, polyurethane or polyethylene terephthalate (PET). The seal member 50 is provided to prevent the toner scraped off by the cleaning blade 45 from flowing backward from the waste toner storage portion 40b to the collection roller 43 side (opening portion 40a side). The contact roller is in contact with the collection roller 43 at the contact pressure.

  Next, the structure of the collection roller 43 will be described.

  As shown in FIG. 4, the collection roller 43 has an outer peripheral surface having a perfectly circular cross section and rotates around a rotation shaft 43 a. The rotation center O of the collection roller 43 (center of the rotation shaft 43a) is eccentric, and the collection roller 43 has the smallest radius Rmin from the rotation center O to the outer peripheral surface and the distance from the rotation center O to the outer peripheral surface. Has the largest maximum radius Rmax.

  For this reason, when the collection roller 43 rotates around the rotation center O, the seal portion (the seal member 50 and the collection roller 43 is in a state where the small diameter portion of the collection roller 43 is in contact with the seal member 50 (the state shown in FIG. 5). Toner and paper dust Q collect in the contact area). On the other hand, when the large diameter portion of the collection roller 43 passes through the seal member 50 (the state shown in FIGS. 6 and 7), the toner or paper dust Q is removed from the waste toner container 40b side (left side) by the collection roller 43. Is pushed into.

  The difference (radius difference ΔR) between the maximum radius Rmax and the minimum radius Rmin of the collection roller 43 is preferably 0.5 mm or more, and more preferably 1 mm or more and 3 mm or less.

  In the present embodiment, as described above, the collection roller 43 has the minimum radius Rmin having the smallest distance from the rotation center O to the outer peripheral surface and the maximum radius Rmax having the largest distance from the rotation center O to the outer peripheral surface. Have. Thereby, when the collection roller 43 rotates, the toner and paper dust Q at the contact portion (seal portion) between the seal member 50 and the collection roller 43 can be pushed into the waste toner storage portion 40b by the portion having a large diameter. For this reason, the toner and paper dust Q can be prevented from clogging and dropping at the seal portion, and therefore the toner and paper dust Q are conveyed to the intermediate transfer belt 8 via the fur brush 41 and an image defect occurs. Can be suppressed.

  Further, since it is not necessary to reduce the contact pressure of the seal member 50 with respect to the recovery roller 43 in order to suppress clogging of toner and paper dust Q at the seal portion, the sealing performance of the seal member 50 with respect to the recovery roller 43 is reduced. Can be suppressed.

  Further, as described above, the rotation center O of the collection roller 43 is eccentric. Thereby, the collection | recovery roller 43 can be easily formed so that it may have the minimum radius Rmin and the maximum radius Rmax.

  Further, as described above, if the difference (radius difference ΔR) between the maximum radius Rmax and the minimum radius Rmin is set to 1 mm or more and 3 mm or less, it is possible to effectively suppress clogging of toner and paper dust Q at the seal portion. be able to.

  Further, as described above, the urging member 49 that urges the holding member 48 and the cleaning blade 45 toward the collection roller 43 is provided. As a result, even when the radius difference ΔR of the collection roller 43 is large, the holding member 48 and the cleaning blade 45 are displaced in conjunction with the displacement of the outer peripheral surface of the collection roller 43. It is possible to prevent the toner on the surface of the collection roller 43 from passing through the cleaning blade 45 due to a gap between the two.

  Next, a confirmation experiment performed to confirm the effect of the above-described embodiment will be described. This confirmation experiment was conducted for Examples 1 to 4 and Comparative Examples 1 and 2 corresponding to the above embodiment.

Example 1
In Example 1, the collection roller 43 having a diameter of 15 mm was used, and the radius difference ΔR of the collection roller 43 was set to 0.5 mm. The holding member 48 and the cleaning blade 45 were fixed to the housing 40 without using the urging member 49. While using a 100-micrometer-thick urethane sheet as the sealing member 50, the amount of biting of the sealing member 50 with respect to the collection roller 43 was set to 0.8 mm. The free length of the cleaning blade 45 (the length of the portion protruding downward from the holding member 48) and the thickness were 10 mm and 1.6 mm, respectively. Other configurations are the same as those in the above embodiment.

(Examples 2 and 3)
In Examples 2 and 3, the radius difference ΔR of the collection roller 43 was 1 mm and 3 mm, respectively. Other conditions were the same as in Example 1.

Example 4
In Example 4, the radius difference ΔR of the collection roller 43 was set to 3 mm, and the holding member 48 and the cleaning blade 45 were urged toward the collection roller 43 using the urging member 49. Other conditions were the same as in Example 1.

(Comparative Example 1)
In Comparative Example 1, the radius difference ΔR of the collection roller 43 was set to 0 mm. That is, the collection roller 43 whose rotation center O is not eccentric is used. Other conditions were the same as in Example 1.

(Comparative Example 2)
In Comparative Example 2, the radius difference ΔR of the collection roller 43 was set to 0 mm. While using a 50-micrometer-thick urethane sheet as the sealing member 50, the amount of biting of the sealing member 50 with respect to the collection roller 43 was set to 0.3 mm. Other conditions were the same as in Example 1.

  For Examples 1 to 4 and Comparative Examples 1 and 2, 50,000 sheets were continuously printed using a color printer “FS-C5030” manufactured by Kyocera Document Solutions as the image forming apparatus 100.

  In Examples 1 to 4 and Comparative Examples 1 and 2, toner scattering due to clogging and clogging of toner and paper dust Q in the seal portion (contact portion between the seal member 50 and the recovery roller 43) (hereinafter, clogging and the like) The presence or absence of toner leakage (hereinafter referred to as toner leakage) in the seal portion and the presence or absence of toner on the surface of the collection roller 43 slipping through the cleaning blade 45 (hereinafter referred to as toner slipping) are visually observed. confirmed. These results are shown in Table 1. Regarding clogging, toner leakage (sealability), and toner slipping, the practically problematic level was marked with x, the occurrence was recognized but practically problematical level was marked with △, and the completely problematic level was marked with ◯.

  Referring to Table 1, it was found that by providing the collection roller 43 with the radius difference ΔR, it is possible to suppress the occurrence of clogging of toner and paper dust Q. Specifically, in Example 1, clogging or the like can be suppressed to a level having no practical problem, and in Examples 2 to 4, clogging or the like did not occur. On the other hand, in Comparative Examples 1 and 2, clogging or the like having a practically problematic level occurred. This is because the collection roller 43 is provided with a radius difference ΔR, so that when the collection roller 43 rotates, the toner and paper dust Q in the seal portion can be pushed into the waste toner container 40b by the large diameter portion, and clogging occurs. This is considered to be because of the suppression of the above.

  It has also been found that toner leakage can be suppressed by increasing the contact pressure of the seal member 50 against the collection roller 43. Specifically, in Examples 1 to 4 and Comparative Example 1, toner leakage did not occur, and in Comparative Example 2, toner leakage occurred even though there was no practical problem.

  Further, if the radius difference ΔR of the collection roller 43 is increased, toner slippage is likely to occur. However, the biasing member 49 is used to bias the holding member 48 and the cleaning blade 45 toward the collection roller 43 side, thereby suppressing toner slippage. It turns out that you can. Specifically, in Examples 1 and 2, toner slip-through did not occur, and in Example 3, toner slip-out occurred at a level that is not a problem in practice. Further, in Example 4, no toner slip occurred. This is because the cleaning blade 45 is displaced in conjunction with the displacement of the outer peripheral surface of the collection roller 43 even when the radius difference ΔR of the collection roller 43 is large by urging the cleaning blade 45 toward the collection roller 43. It is thought that this is because of this.

  The embodiment disclosed this time should be considered as illustrative in all points and not restrictive. The scope of the present invention is shown not by the above description of the embodiments but by the scope of claims for patent, and further includes all modifications within the meaning and scope equivalent to the scope of claims for patent.

  For example, although an example in which the present invention is applied to a color printer has been described, the present invention is not limited to this. Needless to say, the present invention can be applied to various image forming apparatuses including a cleaning device including a cleaning member, a collection roller, and a seal member, such as a monochrome printer, a color copying machine, a monochrome copying machine, and a facsimile machine.

  In the above embodiment, the fur brush 41 is used as the cleaning member. However, a cleaning roller may be provided instead of the fur brush 41.

  In the above-described embodiment, the example in which the present invention is applied to the belt cleaning unit 19 that removes the residual toner on the surface of the intermediate transfer belt 8 has been described. However, the residual surfaces of the photosensitive drums (image carriers) 1a to 1d are described. The present invention can also be applied to cleaning devices 5a to 5d that remove toner.

  Moreover, in the said embodiment, although the example which formed the outer peripheral surface of the collection | recovery roller 43 in perfect circle shape was shown, the outer peripheral surface of the collection | recovery roller 43 does not need to be perfect circle shape.

8 Intermediate transfer belt (image carrier)
19 Belt cleaning unit (cleaning device)
40 Housing 40a Opening 40b Waste Toner Storage 41 Fur Brush (Cleaning Member)
43 collection roller 45 cleaning blade 48 holding member 49 biasing member 50 seal member 100 image forming apparatus O rotation center Rmax maximum radius Rmin minimum radius ΔR radius difference (difference)

Claims (5)

A housing formed with an opening facing the image carrier, and a waste toner container for storing toner scraped off from the surface of the image carrier;
A cleaning member disposed near the opening of the housing and scraping off residual toner on the surface of the image carrier;
A rotatable collection roller for collecting waste toner adhering to the cleaning member;
A cleaning blade that scrapes off waste toner on the surface of the collecting roller;
A sheet-like seal member that is disposed in contact with the collection roller so as to extend in the longitudinal direction of the collection roller and suppresses the backflow of the waste toner from the waste toner container to the opening;
With
The cleaning apparatus, wherein the collection roller has a minimum radius having a minimum distance from the rotation center to the outer peripheral surface and a maximum radius having a maximum distance from the rotation center to the outer peripheral surface.   The cleaning device according to claim 1, wherein the rotation center of the collection roller is eccentric.   The cleaning device according to claim 1, wherein a difference between the maximum radius and the minimum radius is 1 mm or more and 3 mm or less. A holding member for holding the cleaning blade;
A biasing member that biases the holding member toward the collection roller;
The cleaning apparatus according to claim 1, further comprising:   An image forming apparatus comprising the cleaning device according to claim 1.

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