JP5396715B2 - Cleaning device and image forming apparatus - Google Patents

Description

  The present invention relates to a cleaning device having a brush roller that abuts on the surface of an object to be cleaned such as an image carrier and removes adhering matter such as toner adhering to the surface of the object to be cleaned, and image formation including the cleaning device Relates to the device.

  When forming a color image in an electrophotographic image forming apparatus such as a copying machine, a printer, a facsimile machine, or a multifunction machine having these functions, Y, M, C, and K corresponding to the original color are used. The latent image is formed on four photosensitive drums, and the visualized four-color image is first transferred onto an endless intermediate transfer belt, then secondarily transferred onto the recording material, and transferred onto the recording material. The fixed image is fixed and discharged.

  In the image forming apparatus as described above, there is provided a cleaning device that removes toner remaining after adhering to the image bearing member of the photosensitive drum or intermediate transfer belt.

  As a member for removing residual toner from the image carrier, there are a cleaning blade and a brush roller.

  When using a cleaning blade, scrape off residual toner adhering to the surface of the image carrier by bringing the edge of the cleaning blade formed in a plate shape from urethane rubber into contact with the outer peripheral surface of the rotating image carrier. To remove. Then, the scraped residual toner is transported outside the cleaning device by a transport screw provided in the cleaning device, and further transported to a predetermined transport destination by a tubular transport means incorporating a transport screw. Then, when the residual toner is discarded, it is conveyed to a collecting container, and when the residual toner is reused, it is conveyed to a developing device.

  However, when the cleaning blade is used, there are a problem that the small-diameter toner is not sufficiently removed and a problem of durability performance due to edge wear.

  On the other hand, in the case of using a brush roller, a brush roller having a plurality of fibers implanted on the peripheral surface thereof is rotated and brought into contact with the outer peripheral surface of the rotating image carrier so that residual toner adhered to the surface of the image carrier is removed. Remove. Then, residual toner adhering to the brush roller is removed by the collecting roller.

  In such a cleaning device using a brush roller, residual toner on the image carrier moves to the brush roller, and residual toner attached to the brush roller further moves to the recovery roller. In this case, if the collection efficiency for collecting the residual toner from the brush roller is low, the residual toner gradually accumulates on the brush roller, and the collection efficiency for collecting the residual toner from the image carrier is also lowered.

  Since the residual toner on the image carrier is agitated by the rotation of the brush roller, the adhesion force of the residual toner to the image carrier is reduced. Therefore, the collection efficiency from the residual toner to the brush roller is high. However, since the residual toner adhering to the brush roller is not agitated by the recovery roller, the recovery efficiency is low.

  As another configuration for removing the residual toner adhering to the brush roller, a surface or rod-like member fixed to the rotating brush roller is brought into contact with the brush roller so that the residual toner is separated from the brush roller and sucked by air. There is a configuration in which a voltage having a polarity opposite to that of the residual toner is applied to the collecting roller. However, if the residual toner is not efficiently removed, it is difficult to sufficiently remove the residual toner only with the force of air or an electric field.

  In such a cleaning device using a brush roller, if the residual toner adheres to the fiber of the brush roller due to long-term use, the image carrier may be wrinkled. Therefore, it is necessary to improve the cleaning performance of residual toner from the brush roller.

  In order to solve such a problem, the base of each fiber in the brush roller was formed by impregnating with resin, and the impregnation height was varied to mix strong fibers and weak fibers. A cleaning device is disclosed in a patent publication (see Patent Document 1).

In this brush roller, the cleaning performance is improved by scraping the residual toner from the image bearing member with a strong fiber and collecting and transporting the residual toner removed with the weak fiber.
JP 2005-10725 A

  However, the technique described in Patent Document 1 does not have a high collection efficiency for collecting residual toner or the like from the brush roller to the collection roller, and is still insufficient to solve the above problem.

  The present invention has been made in view of such problems, and a cleaning device capable of improving the collection efficiency for collecting deposits such as residual toner from a brush roller to a rubbing member such as a collection roller with a simple configuration, and An object of the present invention is to propose an image forming apparatus provided with the cleaning device.

The object is achieved by the invention described below.
1. A plurality of fibers are planted on the peripheral surface, rotate in contact with the surface of the object to be cleaned, and a brush roller that removes adhering matter adhering to the surface of the object to be cleaned; And a rubbing member that removes the adhering matter adhered to the brush roller, when the rubbing member is in sliding contact with the brush roller, a gap between each tip of the plurality of fibers and the rubbing member. The plurality of fibers include a mixture of fibers having different friction coefficients at least at the front end portions, and the plurality of fibers include a first fiber formed from a first resin. And a second fiber in which a second resin having a friction coefficient different from that of the first resin is applied to a tip portion of the first fiber.
2. 2. The cleaning device according to 1, wherein a ratio of the second fiber to the first fiber is 20% or more and 50% or less.
3. The cleaning apparatus according to 1 or 2, wherein the rubbing member is a rotating collection roller.
4). The cleaning apparatus according to any one of claims 1 to 3, wherein the member to be cleaned is an image carrier, and the attached matter is residual toner.
5. 5. The cleaning device according to 4, wherein a voltage having a polarity opposite to that of the residual toner is applied to the rubbing member .
6). The cleaning apparatus according to any one of claims 1 to 5, further comprising a scraper that scrapes off the adhered matter adhering to the rubbing member .
An image forming apparatus comprising the cleaning device according to any one of 7.1 to 6.

  According to the cleaning device of the present invention and the image forming apparatus equipped with the cleaning device, it is possible to improve the collection efficiency for collecting deposits such as residual toner from a brush roller to a rubbing member such as a collection roller with a simple configuration. it can.

  Embodiments of the image forming apparatus according to the present invention will be described below with reference to the drawings.

  First, an example of an image forming apparatus will be described based on the configuration diagram of FIG.

  The image forming apparatus includes an image forming apparatus main body GH and an image reading apparatus YS.

  The image forming apparatus main body GH is called a tandem color image forming apparatus, and includes a plurality of sets of image forming units 10Y, 10M, 10C, and 10K, an intermediate transfer belt 6, a sheet feeding and conveying unit, a fixing device 8, and the like.

  An image reading device YS including an automatic document feeder 201 and a document image scanning exposure device 202 is installed on the upper part of the image forming apparatus main body GH. The document d placed on the document table of the automatic document feeder 201 is transported by a transport unit, and an image on one or both sides of the document is scanned and exposed by the optical system of the document image scanning exposure device 202, and the line image sensor CCD is scanned. Is read.

  A signal formed by photoelectric conversion by the line image sensor CCD is subjected to analog processing, A / D conversion, shading correction, image compression processing and the like in an image processing unit (not shown), and then exposure means 3Y, 3M, Sent to 3C, 3K.

  In the image forming unit 10Y that forms a yellow (Y) image, a charging unit 2Y, an exposure unit 3Y, a developing unit 4Y, and a cleaning unit 5Y are arranged around the photosensitive drum 1Y. In the image forming unit 10M that forms a magenta (M) color image, a charging unit 2M, an exposure unit 3M, a developing unit 4M, and a cleaning unit 5M are arranged around the photosensitive drum 1M. In the image forming unit 10C that forms a cyan (C) color image, a charging unit 2C, an exposure unit 3C, a developing unit 4C, and a cleaning unit 5C are arranged around the photosensitive drum 1C. In the image forming unit 10K that forms a black (K) image, a charging unit 2K, an exposure unit 3K, a developing unit 4K, and a cleaning unit 5K are arranged around the photosensitive drum 1K. The charging unit 2Y and the exposure unit 3Y, the charging unit 2M and the exposure unit 3M, the charging unit 2C and the exposure device 3C, and the charging unit 2K and the exposure device 3K constitute a latent image forming unit.

  The developing units 4Y, 4M, 4C, and 4K include a two-component developer including yellow (Y), magenta (M), cyan (C), and black (K) toner having a small particle diameter and a carrier.

  The intermediate transfer belt 6 is wound around a plurality of rollers and is rotatably supported.

  The fixing device 8 heats and presses the toner image on the recording paper (recording material) P at a nip portion formed between the heated heating roller 81 and the pressure roller 82 and fixes the toner image.

  Thus, each color image formed by the image forming units 10Y, 10M, 10C, and 10K is sequentially transferred onto the rotating intermediate transfer belt 6 by the transfer means 7Y, 7M, 7C, and 7K (primary transfer). A toner image synthesized with a color image is formed. The recording paper P stored in the paper feeding cassette 20 is fed by the paper feeding means 21 and is conveyed to the transfer means 7A through the paper feeding rollers 22A, 22B, 22C, 22D, the registration rollers 23, etc. A color image is transferred onto P (secondary transfer). The recording paper P to which the color image has been transferred is heated and pressurized by the fixing device 8 and the color toner image on the recording paper P is fixed. Thereafter, the sheet is sandwiched between the sheet discharge rollers 24 and placed on the sheet discharge tray 25 outside the apparatus.

  On the other hand, after the color image is transferred onto the recording paper P by the transfer means 7A, the residual toner is removed by the cleaning device 9 from the intermediate transfer belt 6 from which the recording paper P has been separated in curvature.

  Although the above is an image forming apparatus that forms a color image, an image forming apparatus that forms a monochrome image may be used.

  Next, the main configuration of the cleaning device 9 according to the present invention will be described in detail with reference to FIG. FIG. 2 is a sectional view of the cleaning device 9.

  The cleaning device 9 includes a brush roller 91, a collection roller 92, a scraper 93, and a collection screw 94.

  The brush roller 91 has a plurality of fibers made of, for example, polyester resin electrostatically implanted on the peripheral surface of the rotation shaft. Then, it rotates in contact with the surface of the intermediate transfer belt 6 (object to be cleaned) to remove residual toner (adhered matter) adhering to the surface of the intermediate transfer belt 6 as an image carrier. In the figure, since the brush roller 91 rotates in the same clockwise direction as the intermediate transfer belt 6, the outer peripheral surfaces of both move in the opposite direction at the contact position.

Collection roller 92 (rubbing member) is formed of stainless steel or the like, it rotates in contact with the surface of the brush roller 91. In the drawing, since the collection roller 92 rotates in the same clockwise direction as the brush roller 91, the outer peripheral surfaces of both of them move in the opposite direction at the contact position. Further, since a voltage having a polarity opposite to that of the residual toner is applied to the collection roller 92, the residual toner attached to the brush roller 91 can be attracted electrostatically.

  The scraper 93 is made of stainless steel or the like, contacts the recovery roller 92 from the counter direction, and scrapes off residual toner adhering to the recovery roller 92.

  The collection screw 94 conveys residual toner dropped from the brush roller 91 and the collection roller 92 in a direction perpendicular to the paper surface. The residual toner conveyed to the outside of the cleaning device 9 is collected in a collection container (not shown) when discarded, and is conveyed to the developing device when reused.

  In the cleaning device 9 having the above-described configuration, the fibers in the brush roller 91 are mixed with fibers having different friction coefficients at least at the tip. To mix fibers with different friction coefficients at the tip, apply a resin (second resin) different from the resin (first resin) that forms the main fiber (first fiber) to the tip of the main fiber. Fibers formed from a resin (second resin) different from the resin (first resin) forming the main fiber (first fiber), or mixed fibers (second fibers) with the main fibers ( The second fiber) is mixed with the main fiber.

  As a result, since fibers having different frictional forces are mixed in the contact portion between the brush roller 91 and the collection roller 94, the tip speeds of the fibers are different from one fiber to another and are separated. Accordingly, the contact between the fibers becomes active in the vicinity of the front end portion of the fiber where much residual toner adheres, and the residual toner is easily detached due to the vibration of the fiber and the disturbing effect of the residual toner.

  The operation of such different brush rollers is shown in the enlarged view of FIG.

  FIG. 3A is a diagram of a brush roller made of the same fiber, FIG. 3B is a diagram of a brush roller in which the main fiber and a fiber in which another resin is applied to the tip of the main fiber are mixed. 3 (c) is a diagram of a brush roller in which main fibers and fibers formed from a resin different from the main fibers are mixed.

  In FIG. 3, the fiber is drawn only partially.

  In order to manufacture a brush roller in which fibers with different friction coefficients are mixed, for example, a urethane resin, a silicone resin, or a fluorine resin is applied to the tip of the polyester resin, and the main fiber made of the polyester resin and the like are applied. The hair is mixed with the fiber coated with the resin.

  The same applies to the case where fibers of polyester resin and fibers impregnated with fluororesin are mixed, or polyester resin and acrylic fiber are mixed.

  In addition, for example, after a fiber formed from a single polyester resin is planted to form a brush roller, it is possible to apply another resin having a different friction coefficient to the tip of some fibers by post-processing. .

Next, using various types of brush rollers, the recovery efficiency of the residual toner from the intermediate transfer belt to the brush roller, the recovery efficiency of the residual toner from the brush roller to the recovery roller, and the toner slipping state in the cleaning section of the intermediate transfer belt Describes the experiment to be investigated.
(1) Experimental conditions and experimental apparatus: Tandem color image forming apparatus as shown in FIG. 1. Intermediate transfer belt: Substrate: PI, volume resistance: 10 ⁹ Ω, surface resistance: 10 ¹¹ Ω, belt tension : 39.2N
・ Brush roller: Outer diameter: 18 mm, Hair length: 5 mm, Biting amount with the collection roller: 1 mm
・ Brush roller fibers ... Material: Conductive polyester (hereinafter referred to as polyester) mixed with different fibers, wire diameter: 2d, polyester yarn resistance: 10 ⁹ Ω
Collection roller: Material: SUS, outer diameter: 18 mm, surface roughness: Rz 0.1 μm
・ Scraper ・ ・ ・ Material: SUS, Thickness: 0.05mm
(2) Mixed situation of different fibers in the brush roller Example 1: Apply urethane resin to the tip of 10% of all fibers made of polyester Example 2: Apply urethane resin to the tip of 20% of all fibers made of polyester Application Example 3: Application of urethane resin to the tip of 50% of all fibers made of polyester Example 4: Application of urethane resin to the tip of 60% of all fibers made of polyester Example 5: Total fiber made of polyester Example 6: Silicone resin is applied to the tip of 20% of all fibers made of polyester Example 7: Silicone resin is applied to the tip of 50% of all fibers made of polyester Application Example 8: Silicone resin is applied to the tip of 60% of the total fiber made of polyester. Example 9: Made of polyester Example 10: Fluorine resin is applied to the tip of 20% of all fibers made of polyester Example 11: Fluorine resin is applied to the tip of 50% of all fibers made of polyester Example 12: Fluorine resin was applied to the tip of 60% of all fibers made of polyester Example 13: 20% of all fibers made of polyester was impregnated with fluorine resin Example 14: 80% polyester fiber and 20 % Acrylic fiber Comparative Example 1: Polyester with a single whole fiber Comparative Example 2: A resin obtained by mixing 60% nylon fiber and 40% polyethylene fiber with a water-based urethane elastomer and a crosslinking epoxy. Impregnation (fiber as shown in FIG. 16 of Patent Document 1)
(3) Friction coefficient measuring device Device: HEIDON Tribogear Muse 94iII
Slider part ・ ・ ・ Material: SUS, Surface roughness: Rz0.1μm
(4) Coefficient of friction of each fiber

(5) Method of confirming the effect Unremoved toner is attached to the brush roller with the collecting roller removed, and then the collecting roller is attached to attach the toner to the collecting roller, and the mass of the brush roller is measured in each step. Thus, the residual toner collection efficiency from the intermediate transfer belt to the brush roller and the residual toner collection efficiency from the brush roller to the collection roller were calculated.

Further, after continuously printing 1000 image patterns with a printing rate of 20%, the state of toner passing through the cleaning portion of the intermediate transfer belt by the brush roller was visually confirmed.
(6) Experimental results

  The toner slipping state in the cleaning portion of the intermediate transfer belt is as follows.

○: No slippage occurred Δ: Slight slippage occurred ×: Passage occurred (7) Consideration Regarding the recovery efficiency from the intermediate transfer belt to the brush roller, there is no difference between Examples 1 to 14 and Comparative Examples 1 and 2. Regarding the collection efficiency from the brush roller to the collection roller, each of Examples 1 to 14 was 60% or more, which was significantly improved over Comparative Examples 1 and 2. In other words, in Examples 1 to 14, the total cleaning performance from the intermediate transfer belt to the collection roller via the brush roller was improved.

  This is because, in the contact portion between the brush roller and the collection roller, fibers having different frictional forces are mixed in Examples 1 to 14, and therefore the tip speed of the fiber varies for each fiber in the contact portion, and the toner is This is because the contact between the fibers becomes active in the vicinity of the tip portion of the many fibers, and the toner is easily moved in the electric field due to the vibration of the fibers and the disturbance effect of the adhered toner.

  When polyester resin is used as the brush roller fiber, apply urethane resin or silicone resin with a higher friction coefficient than polyester resin to the tip, or apply fluorine resin with a lower friction coefficient than polyester resin to the tip. Favorable toner recovery performance can be obtained by mixing fibers having different frictional forces.

  Further, when other resin is applied to the tip of the fiber, if the ratio of the fiber to which the other resin is applied is 10% or less, the toner disturbance effect as described above is small, and the recovery from the brush roller to the recovery roller is performed. The efficiency is not improved so much. On the other hand, if the ratio of the fibers coated with other resins is 60% or more, the amount of toner that can be adhered to the fibers coated with other resins is slightly smaller than the original fibers, so that the intermediate transfer belt moves to the brush roller. The recovery efficiency is reduced. Therefore, it is desirable that the ratio of fibers coated with other resins is 20% or more and 50% or less of the entire fibers.

  This ratio is the same when fibers formed from different resins are mixed.

  Furthermore, when polyester fiber and acrylic fiber are mixed as in Example 14, the recovery efficiency from the brush roller to the recovery roller is improved as compared with the comparative example, but it is not sufficient. This is because the difference in the coefficient of friction between the polyester fiber and the acrylic fiber is small. Therefore, it is desirable that the difference in friction coefficient is 0.1 or more.

  From the above experiments, it was proved that the cleaning performance is improved by mixing at least the fibers having different friction coefficients at the tip with the fibers of the brush roller.

  In the above-described cleaning device, the toner is collected on the collecting roller by the electric field, but the toner may be collected by air suction or the like.

  In addition to the residual toner, there are paper dust and the like as deposits collected by the cleaning device.

  Further, the member to be cleaned may be a photosensitive drum other than the intermediate transfer belt as the image carrier. Alternatively, a transfer roller may be used.

  In addition, the rubbing member that is in sliding contact with the brush roller is not limited to the rotating collection roller. For example, the rubbing member is a member having an arcuate curved surface and having an arcuate curved inner wall. A brush roller may be slidably contacted.

1 is a configuration diagram of an image forming apparatus. It is sectional drawing of a cleaning apparatus. It is an enlarged view which shows the effect | action of a brush roller.

Explanation of symbols

9 Cleaning device 91 Brush roller 92 Recovery roller 93 Scraper 94 Recovery screw

Claims (7)

A plurality of fibers are planted on the peripheral surface, rotate in contact with the surface of the object to be cleaned, and a brush roller that removes adhering matter adhering to the surface of the object to be cleaned; A rubbing member that removes the adhering matter adhering to the cleaning device,
The plurality of fibers have at least a tip portion so that different frictional forces act between the tip portions of the plurality of fibers and the rubbing member when the rubbing member is in sliding contact with the brush roller. Fibers with different friction coefficients are mixed,
The plurality of fibers include a first fiber formed from a first resin, and a second resin having a friction coefficient different from that of the first resin applied to a tip portion of the first fiber. And a cleaning device.   The cleaning device according to claim 1, wherein a ratio of the second fiber to the first fiber is 20% or more and 50% or less.   The cleaning device according to claim 1, wherein the rubbing member is a rotating collection roller.   The cleaning apparatus according to claim 1, wherein the object to be cleaned is an image carrier, and the attached matter is residual toner. The cleaning apparatus according to claim 4, wherein a voltage having a polarity opposite to that of the residual toner is applied to the rubbing member . The cleaning apparatus according to claim 1, further comprising a scraper that scrapes off the adhered matter adhering to the rubbing member .   An image forming apparatus comprising the cleaning device according to claim 1.

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