JP2013148757A - Cleaning device and image forming apparatus equipped with same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To suppress uneven deposition of a lubricant to an image carrier.SOLUTION: There is provided a cleaning device which comprises: an image carrier 13; a cleaning blade 41 which contacts with the downstream side from a transfer position in the image carrier 13 to scrape the residual toner T containing a lubricant on the image carrier 13; a recovery screw 42 which is rotated to recover the scraped residual toner T; a toner storing member 43 for temporarily storing the residual toner which is attached to the end part on the side in contact with the image carrier 13 in the cleaning blade 41; and a vibration imparting member 44 which contacts with and separates from the toner storing member 43 depending on whether the vibration imparting member 44 rides on a spiral screw blade 45 formed on the outer periphery of the recovery screw 42.

Description

  The present invention relates to a cleaning device that removes and collects residual toner containing a lubricant on an image carrier, and an image forming apparatus including the same. The image forming apparatus includes various apparatuses such as a copying machine, a printer, a facsimile machine, and a multifunction machine having these functions in a complex manner.

  2. Description of the Related Art Conventionally, in an electrophotographic image forming apparatus, a toner image formed on an image carrier (such as a photoreceptor or an intermediate transfer belt) is transferred to a recording material. When transferring a toner image, a part of the toner may remain on the image carrier due to a mirror image force of the toner, a variation in transfer electric field, or the like. For this reason, a cleaning member is disposed downstream of the transfer position on the image carrier, and residual toner on the image carrier is removed by the cleaning member (see, for example, Patent Document 1).

  As a cleaning member, for example, a plate-like cleaning blade having elasticity such as urethane rubber is known. In this case, residual toner on the image carrier is scraped off by bringing the corner portion on the tip side of the cleaning blade into contact with the surface of the rotating image carrier.

JP 2008-158168 A

  By the way, in the conventional image forming apparatus, a powdery lubricant is added to the toner in advance, and a toner image is formed on the image carrier using the lubricant-containing toner, whereby the surface of the image carrier is lubricated. An agent is supplied, and the lubricant is evenly thinned on the surface of the image carrier with a cleaning blade to reduce the thickness.

  However, since the lubricant added to the toner is generally charged with a polarity opposite to that of the toner by contact with the toner, when the toner image is formed on the image carrier using the toner containing the lubricant, It is more easily supplied to a non-image portion where no toner is supplied than to an image portion (a portion where a toner image is formed) which has been neutralized by exposure on the carrier. For this reason, for example, when a specific image in which a character string, a line, etc. are arranged in the printing direction (which can be said to be the circumferential direction of the image carrier) is continuously printed, the lubricant collects in the non-image portion of the image carrier. A phenomenon of uneven lubricant adhesion that is hardly supplied to the image portion occurs. Such uneven adhesion of the lubricant causes non-uniformity in the potential of the image carrier (non-uniform charging). As a result, for example, when printing a halftone image, non-uniformity in image density occurs due to non-uniformity in potential. There is a risk of printing a defective image in which the boundary portion between the portion where the lubricant remains and the portion where the lubricant does not appear looks like a long streak in the printing direction.

  An object of the present invention is to provide a cleaning apparatus and an image forming apparatus that have been improved by examining the above-described present situation.

  The invention according to claim 1 relates to a cleaning device, an image carrier, a cleaning blade that contacts a downstream side of a transfer position on the image carrier and scrapes residual toner containing lubricant on the image carrier, and the scraper. A collecting screw that rotates and collects the residual toner taken, a toner reservoir member for temporarily retaining residual toner attached to a tip of the cleaning blade that is in contact with the image carrier, and an outer periphery of the collecting screw And a vibration imparting member that comes in contact with and separates from the toner reservoir member depending on whether or not it rides on a spiral screw blade formed in the portion.

  According to a second aspect of the present invention, there is provided an image forming apparatus comprising the cleaning device according to the first aspect.

  According to the present invention, when scraping the residual toner containing the lubricant on the image bearing member, the vibration imparting member gets on and off the screw blades of the collecting roller based on the rotation of the collecting screw. Then, the toner reservoir member is shaken to vibrate the residual toner containing the lubricant after scraping, which is accumulated on the toner reservoir member, and the residual toner containing the lubricant after scraping is moved and diffused on the toner reservoir member. . For this reason, the residual toner containing lubricant after scraping can also come into contact with an image portion on the image carrier (a portion where the supply of lubricant was insufficient for forming a toner image), and lubrication to the image portion. The agent can be supplied, for example, even when a specific image in which a character string, a line, and the like are arranged in a printing direction (also referred to as a circumferential direction of the image carrier) is continuously printed, Lubricant adhesion unevenness on the surface of the image carrier can be reduced by supplying a lubricant to the image portion. As a result, for example, when printing a halftone image or the like, image density unevenness occurs due to potential unevenness due to uneven adhesion of the lubricant, or the boundary between the remaining portion and the absence of the lubricant is long in the printing direction. There is an effect that it is possible to prevent the possibility of printing a defective image that looks like a streak.

FIG. 2 is a schematic explanatory diagram of a printer according to an embodiment. It is a schematic explanatory drawing of a photoreceptor cleaner. It is a schematic perspective view explaining the relationship between a photosensitive drum and a cleaning blade. It is a figure which shows the result of the image density nonuniformity after printing 100 sheets of images in which a plurality of thick lines extend in the printing direction. FIG. 6 is a schematic explanatory diagram illustrating another example of a toner reservoir member.

  Hereinafter, an embodiment in which the present invention is applied to a tandem color digital printer (hereinafter referred to as a printer), which is an example of an image forming apparatus, will be described with reference to the drawings. In addition, in the following description, when using a term indicating a specific direction or position (for example, “left / right”, “up / down”, etc.) as necessary, the direction orthogonal to the paper surface in FIG. ing. These terms are used for convenience of explanation, and do not limit the technical scope of the present invention.

(1). Overview of Printer First, an overview of the printer 1 will be described with reference to FIG. As shown in FIG. 1, the printer 1 includes an image process device 3, a paper feeding device 4, a fixing device 5, and the like in a housing 2. Although not shown in detail, the printer 1 is connected to a network such as a LAN, and is configured to execute printing based on the command when receiving a print command from an external terminal (not shown). Yes.

  The paper feeding device 4 located at the lower part in the housing 2 includes a paper feeding cassette 21 that accommodates the recording material P, a pickup roller 22 that feeds the recording material P in the paper feeding cassette 21 from the uppermost layer, and a fed recording material P. A separation roller pair 23 that separates the sheets one by one and a timing roller pair 24 that conveys the recording material P separated into one sheet to the image processing apparatus 3 at a predetermined timing are provided. The recording material P in each paper feed cassette 21 is sent out one by one from the uppermost layer to the conveyance path 30 by the rotation of the pickup roller 22 and the separation roller 23. The conveyance path 30 passes from the paper feeding cassette 21 of the paper feeding device 4 to the upper portion of the housing 2 through the nip portion of the timing roller pair 24, the secondary transfer nip portion of the image processing device 3, and the fixing nip portion of the fixing device 5. To the discharge roller pair 26 at

  The recording material P in the paper feed cassette 21 is set to a center reference that is conveyed in the direction of arrow S toward the conveyance path 30 with the center of the sheet passing width (width dimension orthogonal to the conveyance direction S) as a reference. In the embodiment, the paper feed cassette 21 is provided with a pair of side regulating plates 25 that bring the recording material P before being fed into the center reference. The pair of side portion regulating plates 25 are configured to move in close proximity to each other in the sheet passing width direction (direction perpendicular to the transport direction S). By sandwiching the recording material P in the paper feed cassette 21 from both sides in the sheet passing width direction by the pair of side portion regulating plates 25, the recording material P in the paper feed cassette 21 is set to the center reference regardless of the standard. . Therefore, the transfer process in the image processing apparatus 3 and the fixing process in the fixing apparatus 5 are also executed on the basis of the center.

  The image processing device 3 positioned above the paper feeding device 4 plays a role of transferring a toner image formed on a photosensitive drum 13 which is an example of an image carrier to a recording material P, and an intermediate transfer belt. 6 and a total of four image forming sections 7 corresponding to the respective colors of yellow (Y), magenta (M), cyan (C) and black (K). The intermediate transfer belt 6 is also an example of an image carrier, and is wound around a driving roller 8 located on the right side of the central part in the housing 2 and a driven roller 9 located on the left side of the central part. A secondary transfer roller 10 is disposed outside the portion of the intermediate transfer belt 6 that is wound around the drive roller 8. A contact portion between the intermediate transfer belt 6 and the secondary transfer roller 10 is a secondary transfer nip portion which is a secondary transfer region. A transfer belt cleaner 12 that removes untransferred toner on the intermediate transfer belt 6 is disposed outside the portion of the intermediate transfer belt 6 that is wound around the driven roller 9. A control unit 28 that performs overall control of the printer 1 is disposed between the image processing apparatus 3 and the sheet feeding apparatus 4 in the housing 2.

  The four image forming units 7 are arranged along the intermediate transfer belt 6 in the order of yellow (Y), magenta (M), cyan (C), and black (K) from the left in FIG. They are arranged side by side. In FIG. 1, for convenience of explanation, symbols Y, M, C, and K are attached to the image forming units 7 according to the reproduction colors. Each image forming unit 7 includes a photosensitive drum 13. Around the photosensitive drum 13, a charger 14, an exposure unit 19, a developing unit 15, a primary transfer roller 16, and a photosensitive cleaner 17 are arranged in this order along the clockwise rotation direction in FIG. 1. A contact portion between the photosensitive drum 13 and the intermediate transfer belt 6 is a primary transfer nip portion which is a primary transfer region.

  In each image forming unit 7, when a laser beam is projected from the exposure unit 19 onto the photosensitive drum 13 charged by the charger 14, an electrostatic latent image is formed. The electrostatic latent image is reversely developed with toner supplied from the developing unit 15 to be a toner image of each color, and is transferred from the photosensitive drum 13 in the order of yellow, magenta, cyan, and black in the primary transfer nip portion. Primary transfer is performed on the outer peripheral surface of the belt 6 and overlapped. Untransferred toner remaining on the photosensitive drum 13 is scraped off by the photosensitive cleaner 17 and removed from the photosensitive drum 13. Then, when the recording material P passes through the secondary transfer nip portion, the superimposed four color toner images are secondarily transferred onto the recording material P all at once. Untransferred toner remaining on the intermediate transfer belt 6 is scraped off by the transfer belt cleaner 12 and removed from the intermediate transfer belt 6.

  Note that a lubricant is added to the toner supplied from the developing unit 15, and when a toner image is formed on the photosensitive drum 13, the lubricant is also supplied to the surface of the photosensitive drum 13 together with the toner. Then, the lubricant on the photosensitive drum 13 is leveled and thinned when scraped off by the photosensitive cleaner 17.

  The fixing device 5 positioned above the secondary transfer roller 10 in the image processing apparatus 3 includes a fixing roller 31 incorporating a heat source such as a halogen lamp heater, and a pressure roller 32 facing the fixing roller 31. A contact portion between the fixing roller 31 and the pressure roller 32 is a fixing nip portion which is a fixing region. The recording material P on which the unfixed toner image is passed through the secondary transfer nip portion is heated and pressurized when passing through the fixing nip portion between the fixing roller 31 and the pressure roller 32, and the recording material P An unfixed toner image is fixed thereon. Thereafter, the recording material P is discharged onto the paper discharge tray 27 by the rotation of the pair of discharge rollers 26.

(2). Detailed Structure of Photoconductor Cleaner Next, the detailed structure of the photoconductor cleaner 17 will be described with reference to FIGS. 2 and 3. As shown in FIG. 2, the photoreceptor cleaner 17 includes a cleaning blade 41, a collection screw 42, a toner reservoir member 43, and a vibration applying member 44 in the housing 40.

  The cleaning blade 41 is a plate-like member having elasticity such as urethane rubber, for example, and contacts the downstream side of the primary transfer nip portion (transfer position) in the photosensitive drum 13, and is rotated by the rotation of the photosensitive drum 13. The lubricant-containing residual toner T on the photosensitive drum 13 is scraped off. The cleaning blade 41 according to the embodiment extends in a counter direction opposite to the rotation direction of the photosensitive drum 13, and a corner portion on the tip side thereof is brought into contact with the surface of the photosensitive drum 13. The length of the cleaning blade 41 in the sheet passing width direction is shorter than the length of the photosensitive drum 13 in the sheet passing width direction (length in the axial direction), and the maximum sheet passing width of the photosensitive drum 13 (the maximum printable image). Is set to be longer than significantly).

  The collection screw 42 collects the residual toner T containing lubricant scraped from the photosensitive drum 13 by the cleaning blade 41 and conveys it to, for example, a waste toner case (not shown) outside the housing 40. The housing 40 is rotatably supported by the housing 40 in a posture extending in the paper width direction. A spiral screw blade 45 is provided on the outer periphery of the recovery screw 42. By rotating the recovery screw 42 with a screw drive motor (not shown), the lubricant-containing residual toner T scraped off from the photosensitive drum 13 is conveyed to the outside of the housing 40.

  The toner reservoir member 43 temporarily retains the residual toner T containing lubricant scraped from the photosensitive drum 13 by the cleaning blade 41 in the vicinity of the front end portion of the cleaning blade 41 that contacts the photosensitive drum 13. The tip of the cleaning blade 41 is attached. The toner reservoir member 43 of the embodiment is configured by an elastic body having a thickness of about 2 to 5 mm, such as urethane or foamed sponge. The length of the toner reservoir member 43 in the sheet passing width direction is set to be approximately the same as the length of the cleaning blade 41 in the sheet passing width direction. Residual toner T containing lubricant scraped off from the photosensitive drum 13 stays in a region defined by the surface of the photosensitive drum 13 and the upper surface of the toner reservoir member 43. That is, the residual toner T containing lubricant is temporarily accumulated as a staying toner in a region sandwiched between the surface of the photosensitive drum 13 and the upper surface of the toner reservoir member 43. The toner reservoir member 43 of the embodiment is attached to the distal end portion of the cleaning blade 41 so that the distal end flat surface 46 and the upper surface of the toner reservoir member 43 are parallel to each other.

  The vibration imparting member 44 is a member formed in a comb shape in plan view, and is configured by a polyester film (PET film, PEN film, or the like) having a thickness of about 100 μm. The length of the vibration applying member 44 in the sheet passing width direction is also set to be approximately the same as the length of the cleaning blade 41 and the toner reservoir member 43 in the sheet passing width direction. On the longitudinal side of the vibration applying member 44, a plurality of projecting pieces 47 extending toward the toner reservoir member 43 and arranged in a comb shape are formed. The other longitudinal side of the vibration applying member 44 is fixed to the housing 15. Each projecting piece 47 of the vibration applying member 44 can be ridden on the screw blade 45 of the recovery screw 42, and the free end side thereof is located at a position where it can contact the toner reservoir member 43. When each of the projecting piece portions 47 rides on the screw blade 45 or comes off from the screw blade 45 by the rotation of the recovery screw 42, each projecting piece portion 47 swings up and down. By such vertical swinging of each projecting piece portion 47, the free end side thereof contacts and separates from the toner reservoir member 43 to swing the toner reservoir member 43, and the staying toner T (residual toner T containing lubricant) on the toner reservoir member 43. Vibrate. The staying toner T on the toner reservoir member 43 moves and diffuses on the toner reservoir member 43 by vibration, and falls from the toner reservoir member 43. The fallen staying toner T is collected by the collecting screw 42.

  In the above configuration, the free end side of the projecting piece portions 47 of the vibration applying member 44 based on the rotation of the recovery screw 42 swings the toner reservoir member 43 with its free end contacting and separating from the toner reservoir member 43, and the toner reservoir member. The staying toner T on the toner 43 is vibrated, and the staying toner T is moved and diffused on the toner storing member 43. Therefore, the staying toner T containing the lubricant is removed from the image area of the photosensitive drum 13 by exposure. It is also possible to make contact with (a portion where the supply of lubricant for toner image formation was poor), and supply of the lubricant to the image portion becomes possible. For this reason, for example, even when a specific image in which character strings, lines, etc. are arranged in the printing direction (which can be said to be the circumferential direction of the photosensitive drum 13) is continuously printed, the lubricant is supplied to the image portion. Thus, uneven adhesion of the lubricant on the surface of the photosensitive drum 13 can be reduced. As a result, for example, when printing a halftone image or the like, image density unevenness occurs due to potential unevenness due to uneven adhesion of the lubricant, or the boundary between the remaining portion and the absence of the lubricant is long in the printing direction. It is possible to prevent the possibility of printing a defective image that looks like a streak.

  Here, FIG. 4 shows a result of image density unevenness after printing 100 images in which a plurality of thick lines extend in the printing direction. In FIG. 4, (1) corresponds to the embodiment, and when both the toner reservoir member 43 and the vibration imparting member 44 are provided, (2) corresponds to the conventional example, and either the toner reservoir member 43 or the vibration imparting member 44 is present. If not, (3) corresponds to a comparative example, in which only the toner reservoir member 43 is provided. In the evaluation, the pure water contact angle on the surface of the photosensitive drum 13 was measured as an index indicating that the lubricant was adhered to the surface of the photosensitive drum 13. The pure water contact angle is related to the amount of lubricant attached, and the larger the pure water contact angle, the more lubricant is attached to the measurement part (image part or non-image part) on the surface of the photosensitive drum 13. Means. Further, the smaller the difference in the pure water contact angle between the image portion and the non-image portion on the surface of the photosensitive drum 13, the smaller the difference in the lubricant adhesion amount between the image portion and the non-image portion.

  As can be seen from FIG. 4, the amount of lubricant attached to the image portion is the largest in the embodiment (1), and the difference in the amount of lubricant attached between the image portion and the non-image portion is also (1). In the case of this embodiment, the best printing result with the least image density unevenness was obtained. When only the toner reservoir member 43 of (3) was provided, the image density unevenness was slightly improved, but a problem that the boundary portion between the remaining portion of the lubricant and the non-lubricated portion appeared streaky. This is because the vibration imparting member 44 is not provided, so that the staying toner T collected on the toner storing member 43 tends to stay as it is and is not easily replaced, and the lubricant in the staying toner T is consumed (supplied to the photosensitive drum 13). It is guessed that it will run out. Therefore, the staying toner T on the toner reservoir member 43 is diffused and gradually dropped by the vertical swing of the projecting piece portions 47 of the vibration applying member 44 based on the rotation of the recovery screw 42. It is understood that it is effective to steadily supply the lubricant to the image portion.

  FIG. 5 shows another example of the toner reservoir member 43. In this other example, the toner reservoir member 43 exemplified in the previous embodiment is inclined at a smaller angle than the toner repose angle from a horizontal plane substantially horizontal to the gravity (vertical) direction so that the free end side faces the recovery screw 42. It is inclined diagonally downward by α. The reason for this inclination is to smoothly guide the staying toner T toward the recovery screw 42 when dropping the staying toner T from the toner storage member 43. Of course, since the inclination angle α is smaller than the toner repose angle, if the toner reservoir member 43 does not vibrate, the residual toner T containing lubricant scraped off from the photosensitive drum 13 can easily fall from the toner reservoir member 43. There is no.

(3). Others The present invention is not limited to the above-described embodiment, and can be embodied in various forms. For example, a printer has been described as an example of the image forming apparatus. However, the image forming apparatus is not limited thereto, and may be a copier, a facsimile, or a complex machine having these functions in combination. In addition, the structure of each part is not limited to embodiment of illustration, A various change is possible in the range which does not deviate from the meaning of this invention.

1 Printer (image forming device)
3 Image processing device 6 Intermediate transfer belt 7 Image forming unit 13 Photosensitive drum (image carrier)
17 Photoconductor cleaner 41 Cleaning blade 42 Recovery screw 43 Toner reservoir member 44 Vibration imparting member

Claims (2)

An image carrier;
A cleaning blade that contacts the downstream side of the transfer position on the image carrier and scrapes the residual toner containing lubricant on the image carrier;
A collection screw for rotating and collecting the scraped residual toner;
A toner reservoir member for temporarily retaining residual toner attached to the tip of the cleaning blade on the side in contact with the image carrier;
A vibration imparting member that contacts and separates from the toner reservoir member depending on whether or not it rides on a spiral screw blade formed on the outer periphery of the recovery screw;
With
Cleaning device. The cleaning apparatus according to claim 1 is provided.
Image forming apparatus.

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