JP4323896B2 - Image forming apparatus and cleaning apparatus - Google Patents

Description

  BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image forming apparatus such as a copying machine, a printer, and a facsimile machine that forms an image by electrophotography, and more particularly, a magnet that uses magnetic toner and non-magnetic toner as a developer and further removes residual toner on an image carrier. The present invention relates to an image forming apparatus including a cleaning device having a roller.

  As an image forming apparatus such as a copying machine, a printer, or a facsimile that forms an image by electrophotography, a toner image electrostatically formed on the surface of a photosensitive drum as an image carrier is electrostatically applied to a recording material such as paper. In general, an image forming apparatus for transferring images is generally used.

  In such an image forming apparatus, it is necessary to sufficiently clean the residual toner that is not transferred to the recording material side at the time of transfer and remains on the photosensitive drum as it is for the next image formation, As a cleaner for this purpose, a cleaning blade made of an elastic material such as urethane rubber is pressed into contact with the surface of the photosensitive drum to remove residual toner, and has already been widely put into practical use.

  In recent years, from the viewpoint of extending the life of a photosensitive drum, in an image forming apparatus using an a-Si photosensitive drum, not only residual toner, but also organic substances to be deposited and high-voltage members (such as a charger) in the apparatus are used. It is necessary to remove various foreign substances that may adhere to the photosensitive drum and cause deterioration of image quality, such as corona products due to the presence, but such foreign substances could not be completely removed by the cleaning blade alone. .

For this reason, particularly in the case of an image forming apparatus using an a-Si photosensitive member and a one-component magnetic toner, as shown in FIGS. 10 and 11, foreign matter such as transfer residual toner remaining on the surface of the photosensitive drum 100 is scraped off. In some cases, the magnet roller 101 is disposed in the vicinity of the cleaning blade together with the cleaning blade 103 to be removed. That is, by using the magnetic property of the toner, the magnetic brush 102, which is a toner layer of a certain thickness formed on the magnet roller 101 with the toner once collected, is used to rub and remove various foreign matters as described above. Yes. The magnetic brush 102 is uniformly formed by a toner coat amount regulating member 105. (See Patent Document 1)
On the other hand, the color toner in a multicolor image forming apparatus of two or more colors is generally configured by mixing a dye and a pigment in a transparent resin in order to make the color of a printed image clear. In many cases, the toner is a non-magnetic toner. In addition, when the configuration uses all non-magnetic toner including black toner, the residual toner on the surface of the photosensitive drum is often removed with the above-described cleaning blade configuration.

  However, since one-component magnetic toner does not require toner density control and the developing device has a simpler configuration than two-component, there are cases where it is used as a black toner. When the cleaning device 107 having the magnet roller 101 is applied, the color toner is not attracted to the magnet roller 101, and it cannot be avoided that a problem occurs in the cleaning function.

  Further, in order to match the cleaning action with the non-magnetic toner, it is possible to eliminate the magnet roller 101 and rely only on the cleaning blade 103 because of the advantages of the magnet roller 101 as described above. It is not a good idea to obtain an image because the frequency is considered to be the largest. In other words, it is desired to clean the non-magnetic toner without impairing the effect that the magnet roller 101 exhibits in cleaning the magnetic toner.

  Therefore, when the non-magnetic toner is collected in the cleaning device 107 including the magnet roller 101, the non-magnetic toner is initially applied to the magnetic toner on the magnet roller 101 by the action of electrostatic attraction or van der Waals force. It adheres and is removed from the photosensitive drum 100, but when a certain amount of non-magnetic toner is supplied, it is released without being captured and overflows to the outside or in the gap between the magnet rollers 101. For example, the cleaning function may be impaired due to clogging, or it may be rubbed with the cleaning blade 103 and fused onto the photosensitive drum 100.

  That is, the magnetic brush 102 formed on the surface of the magnet roller 101 has a capturing function for non-magnetic toner of a certain amount or less. However, when the non-magnetic toner is supplied thereafter, the capturing becomes abrupt. Function declines.

For this reason, conventionally, measures have been taken to prevent deterioration of the cleaning function by supplying magnetic toner to the cleaning device 107 at certain intervals according to the color image formation frequency and reducing the ratio of non-magnetic toner. . (See Patent Document 2)
Japanese Patent Laid-Open No. 2003-15496 Japanese Patent Publication No. 6-73040

  However, as described above, the toner coating amount restricting member 105 has the convex portions 105a and 105b scraping off the toner at both ends of the magnet roller 101, so that toner recoating is not performed at both ends of the magnet roller. .

  Therefore, not only the advantage of the above-described configuration is not applied in the range of the convex portions 105a and 105b, but also the non-magnetic toner (residual toner, fog toner, etc.) on the photosensitive drum 100 is directly applied to the cleaning blade 103 in a portion where the toner is not recoated. Supplied to the edge of Since the blade pressure and the like of the cleaning blade is originally determined for the magnetic toner, if toner with a high ratio of non-magnetic toner is supplied, the toner may slip through and the cleaning performance is deteriorated.

  In order to prevent the deterioration of the cleaning property as described above, it is conceivable to reduce the width of the convex portions at both ends of the toner coat amount regulating member 105. However, the toner amount on the magnet roller is limited to the convex portions 105a and 105b. Therefore, if the convex portions at both ends of the toner coating amount regulating member 105 are narrowed, the toner scraping ability on the magnet roller is reduced and the toner supplemented on the magnet roller is saturated.

  Accordingly, the present invention provides an image forming apparatus having a cleaning device provided with a magnet roller, wherein the toner coat amount regulating member achieves both a toner scraping ability on the magnet roller and a rubbing removal ability on the photosensitive drum, and a magnetic toner. In addition, an object of the present invention is to provide an image forming apparatus that can maintain a stable cleaning function for a non-magnetic toner for a long time.

In order to achieve the above object, the present invention provides a cleaning device for removing toner remaining on an image carrier, wherein the cleaning means is disposed close to or in contact with the longitudinal direction of the image carrier. A rotatable magnet roller, a cleaning blade that contacts the image carrier on the downstream side in the rotation direction of the image carrier with respect to the magnet roller, and removes toner remaining on the carrier; A toner coat amount regulating member that is arranged close to the longitudinal direction of the magnet roller and regulates the amount of magnetic toner coat formed on the magnet roller, and the longitudinal direction of the toner coat amount regulating member Both end regions are formed so as to be substantially in contact with both end regions in the longitudinal direction of the magnet roller with almost no gap, and the longitudinal direction of the magnet roller In the end region, the amount of the magnetic toner coat is substantially zero, or the amount of the magnetic toner coat is small compared to the magnet roller central region, and the end region is formed by the magnetic toner coat formed on the magnet roller central region. In the cleaning device that removes the residual toner by rubbing, the problem is solved by having a recess in a part of each end region in the longitudinal direction of the toner coating amount regulating member.

In another aspect of the present invention for achieving the above object, toner is attached to an image carrier and an electrostatic latent image formed on the image carrier, and the electrostatic latent image is visualized as a toner image. Developing means for transferring, a transfer means for transferring the toner image to a transfer material, and a cleaning means for removing toner remaining on the image carrier after the toner image is transferred to the transfer material by the transfer means. Prepared,
The cleaning means is disposed close to or in contact with the longitudinal direction of the image carrier, and a rotatable magnet roller, and the image carrier downstream of the image carrier in the rotation direction of the image carrier. A cleaning blade that contacts the body and removes toner remaining on the carrier, and an amount of magnetic toner coat formed on the magnet roller, which is disposed in close proximity along the longitudinal direction of the magnet roller A toner coat amount regulating member for regulating the magnet coating, and forming both end regions in the longitudinal direction of the toner coat amount regulating member so as to be substantially in contact with both end regions in the longitudinal direction of the magnet roller with almost no gap. The both end regions in the longitudinal direction of the roller are substantially zero in the amount of the magnetic toner coat, or are compared with the central region of the magnet roller. In an image forming apparatus in which the amount of magnetic toner coat is small, and the remaining toner is removed by rubbing with the magnetic toner coat formed on the central region of the magnet roller, the longitudinal direction of the toner coat amount regulating member It solves by having a recessed part in a part of each both-ends area.

  As described above, according to the present invention, the toner coating amount regulating member achieves both the toner scraping ability on the magnet roller and the rubbing removal ability on the photosensitive drum, and can be used for both magnetic toner and non-magnetic toner for a long time. A stable cleaning function can be maintained.

  Hereinafter, the present invention will be described based on the illustrated embodiments.

<Embodiment 1>
FIG. 1 is a schematic configuration diagram showing an image forming apparatus according to Embodiment 1 of the present invention. The image forming apparatus of the present embodiment is an electrophotographic full-color digital copying machine.

  The image forming apparatus includes a digital full-color image reader unit (hereinafter referred to as a reader unit) A in the upper portion and a digital full-color image printer unit (hereinafter referred to as a printer unit) B in the lower portion.

  In the reader unit A, the original 30 is placed on the original table glass 31 and exposed and scanned by the exposure lamp 32, whereby the reflected light image from the original 30 is condensed on the full-color CCD sensor 34 by the lens 33, and color color separation is performed. An image signal is obtained. The color-separated image signal is processed by a video processing unit (not shown) through an amplifier circuit (not shown) and sent to the printer unit B.

  In the printer unit B, the photosensitive drum 1 as an image carrier is supported rotatably in the direction of the arrow (clockwise). Around the photosensitive drum 1, along the rotation direction, there are a corona charger (primary charger) 2, a laser exposure optical system (exposure device) 3, and four colors (yellow, cyan, magenta, black). Developing units 4y, 4c, 4m, 4Bk, a transfer device 5, a cleaning device 6 and the like are arranged.

  The laser exposure optical system 3 receives an image signal from the reader unit A, converts this image signal into an optical signal at a laser output unit (not shown), and then rotates the laser beam converted into the optical signal at high speed. Reflected by the polygon mirror 3a, the surface of the photosensitive drum 1 is image-exposed through the lens 3b and the mirror 3c.

  Then, the printer unit B rotates the photosensitive drum 1 in the direction of the arrow (clockwise) at the time of image formation, discharges the surface of the photosensitive drum 1 with a pre-exposure lamp (not shown), and then the corona charger 2 uses a predetermined polarity / Charge uniformly to potential. Then, image exposure E corresponding to the image information of the original 30 is performed for each separation color (yellow, cyan, magenta, black) from the laser exposure optical system 3 to form an electrostatic latent image on the surface of the photosensitive drum 1.

  Then, the developing devices 4y, 4c, 4m, and 4Bk are sequentially operated for each separation color to develop the electrostatic latent image on the photosensitive drum 1, and each color (resin and pigment base on the photosensitive drum 1 ( Yellow, cyan, magenta, and black) toner images are formed. In the present embodiment, the developing devices 4y, 4c, and 4m use nonmagnetic toner, and the developing device 4Bk uses magnetic toner. Each of the developing units 4y, 4c, 4m, and 4Bk is configured to approach the photosensitive drum 1 alternatively according to each separation color by the operation of the eccentric cams 24y, 24c, 24m, and 24Bk.

  Then, the recording material P such as paper is fed from the recording material cassette 48a or 48b by the paper feeding rollers 46a, 47a, 47b or 46b, 47c, 47d in accordance with the timing of image formation, and the conveying rollers 44, 42, The toner image on the photosensitive drum 1 is transferred to the recording material P conveyed to the opposing position (image transfer position) between the transfer device 5 and the photosensitive drum 1 through the recording material conveyance path 27 by 40, 54, and 55.

  The transfer device 5 includes a transfer drum 5a, a transfer charger 5b, an adsorption charger 5c for electrostatically adsorbing the recording material P, an adsorption roller 5g opposed thereto, an inner charger 5d, and an outer charger 5e. In addition, a recording material carrying sheet 5f made of a dielectric material is integrally stretched in a cylindrical shape in an opening area of the peripheral surface of the transfer drum 5a that is axially supported so as to be rotationally driven. In the present embodiment, a dielectric sheet such as a polycarbonate film is used as the recording material carrying sheet 5f.

  By rotating the drum-shaped transfer drum 5a, the toner image on the photosensitive drum 1 is transferred onto the recording material P carried (electrostatically attracted) on the recording material carrying sheet 5f by the transfer charger 5b. In this way, toner images of each color (yellow, cyan, magenta, black) are sequentially superimposed and transferred onto the recording material P that is electrostatically attracted and conveyed to the recording material carrying sheet 5f, thereby forming a full-color image.

  When the transfer of the four color toner images is thus completed, the recording material P is separated from the transfer drum 5a by the action of the separation claw 8a, the separation push-up roller 8b, and the separation charger 5h. The separated recording material P is conveyed to the fixing device 9 and heated and pressed at the fixing nip between the fixing roller 9a and the pressure roller 9b of the fixing device 9 to fix the full color image on the surface. The recording material P on which the full-color image is fixed is discharged to the paper discharge tray 26 via the transport path switching guide 19.

  On the other hand, transfer residual toner or the like remaining on the surface of the photosensitive drum 1 after the toner image transfer is removed by the cleaning device 6 and used for the next image formation (the configuration of the cleaning device 6 in this embodiment and the like). The operation will be described later).

  Further, when forming images on both sides of the recording material P, the recording path P is driven immediately after the recording material P passes through the fixing device 9, and the image is fixed on one side as described above. After the recording material P is once guided to the reversing path 21a through the conveying vertical path 20, it is retreated in the direction opposite to the feeding direction with the rear end when fed by the reverse rotation of the reversing roller 21b. Then, the paper is conveyed to the double-sided conveyance path 21c in a state where the front and back sides are reversed. Then, after the image is formed again on the other surface by the above-described image forming process by the refeed roller 56, it is discharged to the paper discharge tray 26.

  Further, the surface of the recording material carrying sheet 5f of the transfer drum 5a is contaminated by the scattering and adhesion of powders such as toner and the oil adhering to the recording material P. However, the fur brush 5m and the recording material carrying sheet are added thereto. Cleaning is performed by the action of the back fur brush 5j facing through 5f, and the action of the oil removing roller 5n and the backup brush 5k facing this through the recording material carrying sheet 5f. Such cleaning is performed as needed before image formation or when jamming (paper clogging) occurs.

  In the present embodiment, the eccentric cam 5p and the cam follower 5i are provided outside the transfer drum 5a, and the eccentric cam 5p is rotated to operate the cam follower 5i integrated with the transfer drum 5f. The gap between the recording material carrying sheet 5f on the surface of the transfer drum 5a and the photosensitive drum 1 can be arbitrarily set. The transfer drum 5a is separated from the photosensitive drum 1 except during image formation.

  Next, the cleaning device 6 in the present embodiment will be described.

  FIG. 2 is a top view of the cleaning device 6 in the present embodiment, and FIG. 3 is a side sectional view of the cleaning device 6 in the present embodiment.

  The cleaning device 6 is provided on the downstream side of the corona charger (primary charger) 2 with respect to the rotation direction of the photosensitive drum 1. The cleaning device 6 remains on the surface of the photosensitive drum 1 with the leading edge abutting against the photosensitive drum 1. A cleaning blade 12 that scrapes off foreign matters such as transfer residual toner, and a magnet roller 10 disposed in the vicinity of the photosensitive drum 1 on the upstream side of the cleaning blade 12 with respect to the rotation direction of the photosensitive drum 1. . A blade-like toner coat amount regulating member 13 made of a non-magnetic material is provided in the vicinity of the circumferential surface of the magnet roller 10 along the longitudinal direction thereof.

  The magnet roller 10 is rotationally driven so as to rotate in the same direction as the photosensitive drum 1 at a position facing the photosensitive drum 1. In the image forming operation described above, these magnetic toners remaining on the surface of the photosensitive drum 1 without being transferred after developing with the nonmagnetic toner of the developing devices 4y, 4c, and 4m and developing with the magnetic toner of the developing device 4Bk. Part of the magnetic brush 11 is formed on the surface of the magnet roller 10 as a toner layer having a constant thickness determined by the layer thickness regulation by the toner coating amount regulating member 13.

  The toner coat amount regulating member 13 is arranged so that the thickness of the magnetic brush 11 formed on the surface of the magnet roller 10 is appropriately larger than the minimum distance between the photosensitive drum 1 and the magnet roller 10. The toner coat amount at both ends in the longitudinal direction of the surface of the magnet roller 10 is thinner than the central region and is almost zero. Both end portions 13a and 13b of the toner coat amount regulating member 13 have a convex shape in an area of 11.5 mm, and the convex shape is a 4.5 mm convex portion, a 2 mm concave portion, and a 5 mm convex shape from the inside of the cleaning device 6. It has a concave shape. By making the both end portions 13a and 13b concave as described above, the magnetic brush 11 reaches a position facing the photosensitive drum 1 as the magnet roller 10 rotates, and the both end portions 13a and 13b as well as the central region are reached. By providing a toner coat area of 2 mm also on the scraping portion, the toner can be surely distributed over the entire edge of the cleaning blade 12, and the surface of the photosensitive drum 1 can be rubbed reliably.

  This is shown in FIG. By providing a notch of 2 mm at the scraped portions of the both end portions 13 a and 13 b of the toner coat amount regulating member, the toner of the magnet roller 10 is supplied to the approximate center of the both end portions 10 mm of the cleaning blade 12. Here, the toner coat amount regulating member 13 is actually the magnet roller 10. The magnetic toner coat 11 and the magnetic toner coat 11 are arranged so as to be substantially in contact with each other.

  When the toner is scraped off at the edge of the cleaning blade 12, the toner runs sideways along the edge, and the toner spreads over the entire edge. This lateral running phenomenon is 2 to 2.5 mm. Further, 3.5 mm from the end of the cleaning blade 12 is overlapped with the scraping portion so that the toner does not leak from the end of the cleaning blade 12 even when the vehicle runs sideways.

  Further, as shown in FIG. 5, even if both end portions 13a and 13b are concave, the toner scraping area on the magnet roller 10 has the same width as the conventional toner scraping areas 105a and 105b. The take-out ability does not decrease.

  Toner that does not form the magnetic brush 11 (collected toner) falls into the cleaning device 6 and is stored, and is further discharged to the outside by the conveying screw 14 as necessary.

  With such a configuration, it is possible to achieve both the toner scraping ability on the magnet roller 10 and the rubbing removal ability on the photosensitive drum 1, and a stable cleaning function for both a magnetic toner and a non-magnetic toner over a long period of time. Can keep.

<Embodiment 2>
In Embodiment 1, both end portions of the blade-like toner coat amount regulating member are formed in a concave shape, but in this embodiment, as shown in FIGS. 6 and 7, a roller made of a non-magnetic material is used. The both ends 15a and 15b of the toner coat amount regulating member 15 are formed to have a diameter slightly larger than the diameter of the central portion so as to form a concave shape. Other configurations and operations are the same as those in the first embodiment, and a description thereof is omitted in this embodiment.

  As described above, also in this embodiment, the toner scraping ability on the magnet roller 10 and the rubbing removal ability on the photosensitive drum 1 can be compatible, and the magnetic toner and the non-magnetic toner are stable for a long time. Can maintain the cleaning function.

<Embodiment 3>
In Embodiment 1, both end portions of the blade-like toner coat amount regulating member are formed in a concave shape, but in this embodiment, as shown in FIGS. 8 and 9, a block made of a non-magnetic material is used. The both end portions 16a and 16b of the toner coating amount regulating member 16 are formed in a protruding piece shape and are formed in a concave shape. Other configurations and operations are the same as those in the first embodiment, and a description thereof is omitted in this embodiment.

  As described above, also in this embodiment, the toner scraping ability on the magnet roller 10 and the rubbing removal ability on the photosensitive drum 1 can be compatible, and the magnetic toner and the non-magnetic toner are stable for a long time. Can maintain the cleaning function.

1 is a schematic cross-sectional view showing a configuration of an image forming apparatus according to Embodiment 1 of the present invention. 1 is a top view of a cleaning device for an image forming apparatus according to Embodiment 1 of the present invention. 1 is a side sectional view of a cleaning device of an image forming apparatus according to Embodiment 1 of the present invention. FIG. 3 is a layout view of the cleaning device end according to the first embodiment of the present invention. FIG. 3 is an end shape diagram of the toner coat regulating member according to the first embodiment of the present invention. FIG. 9 is a top view of a cleaning device for an image forming apparatus according to a second embodiment of the present invention. FIG. 5 is a side sectional view of a cleaning device for an image forming apparatus according to Embodiment 2 of the present invention. FIG. 9 is a top view of a cleaning device for an image forming apparatus according to Embodiment 3 of the present invention. FIG. 9 is a side sectional view of a cleaning device for an image forming apparatus according to Embodiment 3 of the present invention. FIG. 10 is a top view of a cleaning device of an image forming apparatus in a conventional example. FIG. 10 is a side sectional view of a cleaning device for an image forming apparatus in a conventional example.

Explanation of symbols

1,100 Photosensitive drum (image carrier)
2 Corona charger 3 Laser exposure optical system 4y, 4c, 4m, 4Bk Developer (developing means)
5 Transfer device (transfer means)
5a Transfer drum 5f Recording material carrying sheet 6, 107 Cleaning device (cleaning means)
9 Fixing Device 9a Fixing Roller 9b Pressure Roller 10, 101 Magnet Roller 11, 102 Magnetic Brush (Magnetic Toner Coat)
12, 103 Cleaning blade 13, 15, 105 Toner coating amount regulating member 13a, 13b, 15a, 15b, 105a, 105b End portion 14, 106 Conveying screw A Leader portion B Printer portion

Claims (4)

A cleaning device for removing toner remaining on an image carrier,
The cleaning means includes a rotatable magnet roller disposed close to or in contact with the longitudinal direction of the image carrier, and the image carrier on the downstream side in the rotation direction of the image carrier with respect to the magnet roller. A cleaning blade that contacts the carrier and removes the toner remaining on the carrier, and is disposed close to the longitudinal direction of the magnet roller so as to reduce the amount of magnetic toner coat formed on the magnet roller. A toner coat amount regulating member for regulating, and forming both end regions in the longitudinal direction of the toner coat amount regulating member so as to be in contact with the both end regions in the longitudinal direction of the magnet roller with almost no gap, In the both end regions in the longitudinal direction, the amount of the magnetic toner coat is smaller than that in the central region of the magnet roller. In the cleaning device is removed by rubbing the toner the remaining by the magnetic toner coat formed controller central region,
A cleaning device having a recess in a part of each end region in the longitudinal direction of the toner coat amount regulating member.   The cleaning apparatus according to claim 1, wherein the toner includes a magnetic toner and a non-magnetic toner. An image carrier, a developing unit that attaches toner to the electrostatic latent image formed on the image carrier, and visualizes the electrostatic latent image as a toner image, and transfers the toner image to a transfer material A transfer unit; and a cleaning unit that removes toner remaining on the image carrier after the toner image is transferred to a transfer material by the transfer unit, and the cleaning unit is arranged in a longitudinal direction of the image carrier. A magnet roller that is disposed in close proximity to or in contact with the magnet roller, and contacts the image carrier on the downstream side in the rotation direction of the image carrier with respect to the magnet roller, and remains on the carrier. a cleaning blade for removing with which toner, the disposed proximate the longitudinal direction of the magnet roller, the toner coating amount for regulating the amount of magnetic toner coat formed on the magnetic roller on the A longitudinally opposite end region of the toner coat amount regulating member so as to be in contact with the longitudinally opposite end region of the magnet roller with almost no gap, and the longitudinal end region of the magnet roller. Is an image forming apparatus in which the amount of the magnetic toner coat is smaller than that in the magnet roller central region, and the remaining toner is rubbed and removed by the magnetic toner coat formed on the magnet roller central region. In
An image forming apparatus having a recess in a part of each end region in the longitudinal direction of the toner coat amount regulating member. The image forming apparatus according to claim 3, wherein the toner includes a magnetic toner and a non-magnetic toner.

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