JP2008129559A - Cleaning device and image forming apparatus provided with the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a cleaning device which is capable of preventing the accumulation of toner by stirring the toner, without requiring an exclusive drive mechanism and with a simple configuration. <P>SOLUTION: In the cleaning device 6a configured in such a manner that a sweep roller (toner conveying roller) 24 is housed in a toner discharge path in a housing 21, a cylindrical spring-like member (rotating body) 27 which comes into contact with the sweep roller 24, to be driven rotated is rotatably arranged between the inwall of the housing 21 and the sweep roller 24. At this time, two (plurality) spring-like members 27 are arranged in the axial direction of the sweep roller 24. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a cleaning device for removing toner remaining on an image carrier without being transferred onto a recording material, and an image forming apparatus including the same.

  An image forming apparatus such as a copying machine or a laser beam printer adopting an electrophotographic method includes an image carrier that forms a latent image, a developing device that develops the latent image formed on the image carrier as a toner image, A transfer device for transferring a toner image on an image carrier onto a recording material; a cleaning device for removing toner remaining on the image carrier without being transferred onto the recording material; and a toner image transferred onto the recording material. The image forming apparatus includes a fixing device that fixes the image to the recording material.

  By the way, when the image carrier is composed of an amorphous silicon (α-Si) photoconductor, charged products are likely to adhere to the surface, and the chargeability of the photoconductor is reduced particularly in a high temperature and high humidity environment. There is a problem that the flow tends to occur.

  Therefore, a rubbing roller that contacts the image carrier and rotates with a linear velocity difference with respect to the surface of the image carrier is provided in the cleaning device, and the charged product adhering to the surface of the image carrier by the rubbing roller is removed from the residual toner. The charged product and toner (hereinafter simply referred to as “toner”) are scraped off and conveyed to a toner conveying screw by rotation of a toner conveying roller provided in a toner discharge path. .

  However, in the cleaning device in which the shape of the inner wall of the housing on the upstream side (relative to the toner conveying direction) with respect to the toner conveying roller is an inclined surface, the inclined surface of the inner wall of the housing is not provided with a toner conveying function. There is a possibility that toner accumulates on the surface. In particular, in a cleaning device that employs a configuration in which the toner falls toward the slope of the inner wall of the housing, toner accumulates in a columnar shape on the slope, and the toner flow is obstructed, making it impossible to smoothly discharge the toner. End up. Therefore, it is necessary to stir the toner falling on the slope of the inner wall of the housing so that the toner does not accumulate on the slope and solidify. As the agitating member for agitating the toner, a spring-shaped member that does not obstruct the toner flow is effective.

  Therefore, Patent Document 1 discloses a configuration in which the fixing spring is adjacent to the inside of the cartridge and the toner is stirred by rotating the cartridge.

Patent Document 2 discloses a configuration in which the toner is stirred by sliding a stirring coil spring in the developing device.
JP-A-5-281856 Japanese Patent Laid-Open No. 11-174842

  However, the configurations disclosed in Patent Documents 1 and 2 have a drive mechanism for rotating the cartridge and the stirring coil spring, which complicates the drive mechanism and increases assembly man-hours and costs. .

  The present invention has been made in view of the above problems, and an object of the present invention is to provide a cleaning device that can stir toner with a simple configuration and prevent its accumulation without requiring a dedicated drive mechanism. An image forming apparatus is provided.

  In order to achieve the above object, a first aspect of the present invention is a cleaning device in which a toner transport roller is housed in a toner discharge path in a housing, and a cylindrical rotating body that rotates in contact with the toner transport roller. Is rotatably arranged between the inner wall of the housing and a toner conveying roller.

  According to a second aspect of the present invention, in the first aspect of the present invention, a plurality of the rotating bodies are arranged in the axial direction of the toner conveying roller.

  According to a third aspect of the present invention, in the first or second aspect of the present invention, the rotating body is formed of a spring-shaped member.

  According to a fourth aspect of the invention, in the first aspect of the invention, the toner conveying roller is a sweep roller having an elliptical cross section.

  According to a fifth aspect of the present invention, there is provided an image carrier that forms a latent image, a developing device that develops the latent image formed on the image carrier as a toner image, and a toner image on the image carrier on a recording material. And a toner image transferred onto the recording material. 5. A transfer device for transferring to the recording material; and a cleaning device according to claim 1 for removing toner remaining on the image carrier without being transferred onto the recording material. The image forming apparatus includes a fixing device for fixing the toner image to the recording material.

  According to the first aspect of the present invention, since the rotating body agitates the toner by being in contact with the toner conveying roller and driven to rotate, a dedicated drive mechanism for rotationally driving the rotating body becomes unnecessary, and it is simple. With such a configuration, the toner can be agitated to prevent its accumulation, and the toner can be discharged smoothly to obtain a stable cleaning performance.

  According to the second aspect of the present invention, since a plurality of rotating bodies are arranged in the axial direction of the toner conveying roller, each rotating body can be stably rotated by being driven by the rotation of the toner conveying roller.

  According to the third aspect of the present invention, since the rotating body is constituted by the spring-shaped member, the toner can be efficiently stirred without hindering the flow of the toner.

  According to the fourth aspect of the invention, since the sweep roller has an elliptical cross section, the rotating body that rotates in contact with the outer periphery of the sweep roller jumps up and down, so that the effect of stirring the toner by the rotating body is enhanced. It is done.

  According to the fifth aspect of the invention, the toner scraped off from the surface of the image carrier in the cleaning device can be stirred and discharged smoothly with a simple configuration, so that the image forming operation can be performed stably. it can.

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

[Image forming apparatus]
FIG. 1 is a front sectional view of a color copying machine as an embodiment of an image forming apparatus according to the present invention. The illustrated color copying machine includes an image reading device 30 on an upper portion of a main body 100, and an inner central portion of the main body 100. The magenta image forming unit 1M, the cyan image forming unit 1C, the yellow image forming unit 1Y, and the black image forming unit 1BK constituting the image forming unit are arranged in a line at regular intervals.

  The image reading apparatus 30 includes an original table glass 31 on which an original is placed, an exposure lamp 32 that exposes and scans the original placed on the original table glass 31, and an original reflection that the exposure lamp 32 exposes and scans. A plurality of mirrors 33 for further reflecting the light image, a lens 34 for condensing the reflected light image, a full color sensor 35 such as a charge coupled device (CCD) for storing the collected reflected light image, and the like. Yes.

  The image forming units 1M, 1C, 1Y, and 1BK, which are image forming units, have drum type electrophotographic photosensitive members (hereinafter referred to as “photosensitive drums”) 2a, 2b, 2c, and 2d as image carriers. is set up. Around the photosensitive drums 2a to 2d, primary chargers 3a, 3b, 3c and 3d, developing devices 4a, 4b, 4c and 4d, transfer rollers 5a, 5b, 5c and 5d as transfer devices, and the present invention. The cleaning devices 6a, 6b, 6c, and 6d according to FIG.

  The photosensitive drums 2a to 2d are drum-shaped amorphous silicon (α-Si) photosensitive members, and are rotated at a predetermined process speed in a direction indicated by an arrow (counterclockwise in FIG. 1) by a driving device (not shown). The

  The primary chargers 3a to 3d uniformly charge the surfaces of the photosensitive drums 2a to 2d to a predetermined potential by a charging bias applied from a charging bias power source (not shown).

  Further, the developing devices 4a to 4d contain magenta (M) toner, cyan (C) toner, yellow (Y) toner, and black (BK) toner, respectively, and are formed on the photosensitive drums 2a to 2d. The toner of each color is attached to each electrostatic latent image to develop each electrostatic latent image as a toner image of each color (visualization), and the toner is consumed and the developing devices 4a to 4d When a toner replenishment signal is issued because the remaining amount of toner is less than a certain value, toner of each color is replenished from the toner replenishing devices 7a, 7b, 7c and 7d to the developing devices 4a to 4d. The toner replenishing devices 7 a to 7 d are configured as cartridges that can be attached to and detached from the copying machine main body 100.

  The transfer rollers 5a to 5d are arranged so as to be in contact with the photosensitive drums 2a to 2d via an endless intermediate transfer belt 8 at each primary transfer portion (primary transfer nip portion). Here, the intermediate transfer belt 8 constitutes a second image carrier, and is stretched between the secondary transfer counter roller 9 and the tension roller 10 and travels to the upper surface side of each of the photosensitive drums 2a to 2d. Arranged to be possible. The secondary transfer counter roller 9 is disposed so as to be in contact with the secondary transfer roller 11 via the intermediate transfer belt 8 in the secondary transfer portion (secondary transfer nip portion). As the material of the intermediate transfer belt 8, for example, a dielectric resin such as polycarbonate, polyethylene terephthalate (PET), polyvinylidene fluoride (PVdF), or the like is selected. Although not shown, a belt cleaning device for removing residual toner remaining on the surface of the intermediate transfer belt 8 is installed outside the intermediate transfer belt 8 and in the vicinity of the tension roller 10. Yes.

  On the other hand, a laser scanner unit 40 is arranged below each image forming unit 1M, 1C, 1Y, 1BK inside the copying machine main body 100, and a paper feed cassette 50 is detachably installed at the bottom of the main body 100 below the image forming units 1M, 1C, 1Y, 1BK. In this paper feed cassette 50, a plurality of recording materials P are stacked and stored. In the vicinity of the paper feed cassette 50, a pickup roller 13 for feeding the recording material P from the paper feed cassette 50 to the transport path 12 one by one is provided.

  Further, the conveyance path 12 arranged in the vertical direction on one side of the copying machine main body 100 extends to a paper discharge tray 14 provided on the upper surface of the main body 100, and in the middle thereof, a pair of paper feed rollers 15. A registration roller pair 16, a fixing device 17 having a fixing roller 17a and a pressure roller 17b, and a paper discharge roller pair 18 are provided.

  Next, an image forming operation by the color copying machine having the above configuration will be described.

  When an image formation start signal is issued, the photosensitive drums 2a to 2d are driven to rotate in the direction of the arrow in FIG. 1 at a predetermined process speed in each of the image forming units 1M, 1C, 1Y, and 1BK, and these photosensitive drums 2a to 2d. Are uniformly charged positively by the primary chargers 3a to 3d. The laser scanner unit 40 emits a laser beam modulated by a color image signal for each color of the original image read by the image reading device 30 from a laser output unit 41, and the laser beam is emitted from a lens 42 and a plurality of mirrors. 43 and the lens 44, and are projected onto the surfaces of the photosensitive drums 2a to 2d, and electrostatic latent images corresponding to the color image signals of the respective colors are formed on the photosensitive drums 2a to 2d, respectively.

  First, magenta toner is adhered to the electrostatic latent image formed on the photosensitive drum 2a of the magenta image forming unit 1M by the developing device 4a to which a developing bias having the same polarity as the charged polarity of the photosensitive drum 2a is applied. The electrostatic latent image is visualized as a magenta toner image. The magenta toner image is rotationally driven in the direction indicated by the arrow in the primary transfer portion between the photosensitive drum 2a and the transfer roller 5a by the action of the transfer roller 5a to which a primary transfer bias having a polarity opposite to that of the toner is applied. Primary transfer is performed on the intermediate transfer belt 8.

  The intermediate transfer belt 8 on which the magenta toner image has been primarily transferred as described above moves to the next cyan image forming unit 1C. In the cyan image forming unit 1C as well, the cyan toner image formed on the photosensitive drum 2b is transferred onto the magenta toner image on the intermediate transfer belt 8 at the primary transfer portion in the same manner as described above.

  Similarly, the yellow and black toner images formed on the photosensitive drums 2c and 2d of the yellow and black image forming units 1Y and 1BK are respectively formed on the magenta and cyan toner images superimposed and transferred on the intermediate transfer belt 8. In each primary transfer portion, the images are sequentially overlapped, and a full-color toner image is formed on the intermediate transfer belt 8. The transfer residual toner that is not transferred onto the intermediate transfer belt 8 and remains on the photosensitive drums 2a to 2d is removed by the cleaning devices 6a to 6d, and is transported by a waste toner transport unit (not shown) to be supplied to each toner. The toner is collected as waste toner in a toner collecting container formed integrally with the devices 7a to 7d.

  On the other hand, one sheet of recording material P is fed from the sheet feeding cassette 50 to the transport path 12 by the pickup roller 13 and the pair of sheet feeding rollers 15, and this recording material P is the leading edge of the full color toner image on the intermediate transfer belt 8. Is conveyed to the secondary transfer portion by the registration roller pair 16 in accordance with the timing of reaching the secondary transfer portion between the secondary transfer counter roller 9 and the secondary transfer roller 11.

  Then, a full color toner image is transferred to the intermediate transfer belt by the action of the transfer electric field formed by the secondary transfer roller 11 to which the secondary transfer bias having the opposite polarity to the toner is applied to the recording material P conveyed to the secondary transfer unit. The secondary transfer is performed on the recording material P from 8 at the same time.

  Thus, the recording material P onto which the full-color toner image has been transferred is subjected to charge removal processing and electrostatically separated from the intermediate transfer belt 8, and then conveyed to the fixing device 17. In the fixing device 17, a full-color toner image is heated and pressed at the fixing nip portion between the fixing roller 17 a and the pressure roller 17 b to be thermally fixed on the surface of the recording material P, and the toner image is fixed. A series of image forming operations is completed when the recording material P is discharged onto the discharge tray 14 by the discharge roller pair 18. The secondary transfer residual toner that is not transferred onto the recording material P but remains on the intermediate transfer belt 8 is removed by a belt cleaning device (not shown), and is transported by a waste toner transport means (not shown) to be shown. It is collected as waste toner in a collection container.

  Although the present invention has been described with respect to an embodiment in which the present invention is applied particularly to a color copying machine, the present invention is applicable to any other image forming apparatus such as a printer or a facsimile.

[Cleaning device]
Next, details of the configuration of the cleaning device according to the present invention will be described with reference to FIGS. In addition, since all the configurations and operations of the cleaning devices 6a to 6d are the same, only one cleaning device 6a will be described below.

  2 is a front sectional view of the cleaning device according to the present invention, FIG. 3 is a sectional view taken along line AA in FIG. 2, and FIG. 4 is a sectional view taken along line BB in FIG.

  In the cleaning device 6 a, a cylindrical rubbing roller 20 that is long in the direction perpendicular to the paper surface of FIG. 2 is housed in a housing 21. Both ends in the axial direction of the rubbing roller 20 are rotatably supported by the housing 21 and abut against the photosensitive drum 2a and rotate with a predetermined linear velocity difference with respect to the surface of the photosensitive drum 2a. The charged product and transfer residual toner adhering to the surface are scraped off. A roll plate 22 is disposed below the rubbing roller 20 in the housing 21, and an arc-curved surface portion 22 a along the outer periphery of the rubbing roller 20 is formed on a part of the roll plate 22. The curved surface portion 22a covers the lower half of the rubbing roller 20 from below.

  Further, below the rubbing roller 20 across the roll plate 22 in the housing 21, a toner conveying screw 23 that is long in the direction perpendicular to the paper surface of FIG. In the toner discharge path in the vicinity of the toner conveying screw 23, a sweep roller 24, which is a toner conveying roller, is arranged long in the direction perpendicular to the paper surface of FIG. The sweep roller 24 has an elliptical cross section, and both axial ends thereof are rotatably supported by the housing 21. A sheet 25 made of a flexible elastic body whose upper end is fixed to the roll plate 22 is in contact with the outer peripheral surface of the sweep roller 24.

  Thus, in the present embodiment, as shown in FIGS. 2 and 3, the sliding plate 20 is located above the roll plate 22 in the housing 21 and between the rubbing roller 20 and the inner wall of the housing 21. A spring-shaped member 26 is disposed as a cylindrical rotating body that is in contact with the rubbing roller 20 and is driven to rotate. In the present embodiment, the spring-shaped member 26 is constituted by a coil spring, and two spring-shaped members 26 are arranged in the axial direction of the rubbing roller 20 as shown in FIG.

  2 and 4, the toner discharge path below the spring-shaped member 26 in the housing 21, between the inner wall on the slope of the housing 21 and the sweep roller 24, is a sweep roller. A spring-shaped member 27 is disposed as a cylindrical rotating body that is in contact with the rotating member 24 and rotates in a driven manner. In the present embodiment, this spring-shaped member 27 is also constituted by a coil spring, and two spring-shaped members 27 are arranged in the axial direction of the sweep roller 24 as shown in FIG.

  Thus, while the photosensitive drum 2a is rotated in the direction of the arrow (counterclockwise) in FIG. 2 during the image forming operation, the rubbing roller 20 of the cleaning device 6a is in contact with the photosensitive drum 2a. It rotates in the direction of the arrow in FIG. 2 (clockwise direction) with a predetermined linear velocity difference with respect to the surface of the photosensitive drum 2a, and scrapes off charged products and transfer residual toner attached to the surface of the photosensitive drum 2a. The toner (including the charged product) thus scraped off from the surface of the photosensitive drum 2a falls and sequentially accumulates in the gap between the rubbing roller 20 and the roll plate 22, and the arrow a in FIG. As shown, it overflows from the tip of the roll plate 22 and falls.

  By the way, when the rubbing roller 20 rotates in the direction of the arrow in FIG. 2, the spring-shaped member 26 that contacts the rubbing roller 20 is rotated in the direction indicated by the arrow (counterclockwise) in accordance with the direction of the roll plate 22. The toner that has reached the tip is stirred to prevent its solidification. For this reason, the toner does not solidify and accumulate on the front end portion of the roll plate 22, and the toner overflows from the front end portion of the roll plate 22 and falls onto the other spring-shaped member 27.

  The spring-like member 27 abuts on the sweep roller 24 rotating in the arrow direction (counterclockwise) in FIG. 2 and is driven to rotate in the arrow direction (clockwise) in FIG. Prevent solidification. Since the sweep roller 24 has an elliptical cross section, the spring-shaped member 27 that rotates in contact with the outer periphery of the sweep roller jumps up and down to stir the toner more effectively.

  The toner agitated by the spring-shaped member 27 is sent to the toner conveying screw 23 by the sweep roller 24, and is conveyed in the direction perpendicular to the paper surface in FIG. Is collected as waste toner. The toner adhering to the outer peripheral surface of the sweep roller 24 is removed by the sheet 25 that vibrates as the sweep roller 24 rotates.

  As described above, according to the present embodiment, one spring-shaped member 26 abuts against the rubbing roller 20 and is driven to rotate, and the other spring-shaped member 27 abuts against the sweep roller 24 to be driven and rotated. Therefore, a dedicated drive mechanism for rotating the spring-shaped members 26 and 27 is not necessary, and the toner can be stirred and prevented from being deposited with a simple configuration, so that the toner can be discharged smoothly. And stable cleaning performance can be obtained.

  In the present embodiment, since the two spring-shaped members 26 and 27 are arranged in the axial direction of the rubbing roller 20 and the sweep roller 24, the spring-shaped members 26 and 27 are respectively disposed on the rubbing roller 20 and the sweep roller 24. It can be rotated stably by being driven by the rotation.

  Furthermore, in this embodiment, since the spring-shaped members 26 and 27 are constituted by coil springs, the toner can be efficiently stirred without hindering the flow of toner.

  Thus, according to the color copying machine shown in FIG. 1 provided with the cleaning devices 6a to 6d as described above, each of the cleaning devices 6a to 6d was scraped off from the photosensitive drums 2a to 2d by the rubbing roller 20. Since the toner can be stirred and discharged smoothly with a simple configuration, the image forming operation can be performed stably.

  In the above, the embodiment in which the present invention is applied to the cleaning device provided in the color copying machine has been described. However, the present invention is applicable to the cleaning device provided in any other image forming apparatus such as a printer or a facsimile. Of course, the same applies to the above.

1 is a front sectional view of an image forming apparatus (color copying machine) according to the present invention. It is a front sectional view of a cleaning device according to the present invention. It is the sectional view on the AA line of FIG. FIG. 3 is a sectional view taken along line B-B in FIG. 2.

Explanation of symbols

1M, 1C, 1Y, 1BK Image forming units 2a, 2b, 2c, 2d Photosensitive drum (image carrier)
3a, 3b, 3c, 3d Primary charger 4a, 4b, 4c, 4d Developing device 5a, 5b, 5c, 5d Transfer roller (transfer device)
6a, 6b, 6c, 6d Cleaning device 7a, 7b, 7c, 7d Toner replenishing device 8 Intermediate transfer belt 9 Secondary transfer counter roller 10 Tension roller 11 Secondary transfer roller 12 Transfer path 13 Pickup roller 14 Paper discharge tray 15 Paper feed Roller pair 16 Registration roller pair 17 Fixing device 17a Fixing roller 17b Pressure roller 18 Discharge roller pair 20 Rub roller 21 Cleaning device housing 22 Roll plate 22a Arc curved surface portion of roll plate 23 Toner transport screw 24 Sweep roller (toner transport) roller)
25 Sheet 26, 27 Spring-shaped member (rotating body)
Reference Signs List 30 Image reader 31 Platen glass 32 Exposure lamp 33 Mirror 34 Lens 35 Full color sensor P Recording material

Claims (5)

In the cleaning device in which the toner conveying roller is housed in the toner discharge path in the housing,
A cleaning device, wherein a cylindrical rotating body that rotates in contact with the toner conveying roller is rotatably disposed between an inner wall of the housing and the toner conveying roller.   The cleaning device according to claim 1, wherein a plurality of the rotating bodies are arranged in an axial direction of the toner conveying roller.   The cleaning device according to claim 1, wherein the rotating body is formed of a spring-shaped member.   The cleaning device according to claim 1, wherein the toner conveying roller is a sweep roller having an elliptical cross section.   An image carrier that forms a latent image, a developing device that develops the latent image formed on the image carrier as a toner image, a transfer device that transfers the toner image on the image carrier onto a recording material, and recording 5. A cleaning device according to claim 1, wherein the toner remaining on the image carrier without being transferred onto the material is removed, and a fixing device for fixing the toner image transferred onto the recording material to the recording material. An image forming apparatus comprising:

Images