JP4897444B2 - Cleaning device and image forming apparatus having the same - Google Patents

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. It is being scraped off together.

However, in a cleaning device in which the toner discharge port scraped off by the rubbing roller is provided at the top, solid toner is discharged or the toner is discharged to the discharge port, particularly when the toner has poor fluidity. It may accumulate and become a lump. In such a case, the function of discharging the toner is impaired, and the cleaning device does not function normally, and a stable image forming operation becomes impossible. Therefore, by stirring the toner scraped by the rubbing rollers, it is necessary to prevent its solidification, as the stirring member for stirring the toner, the less spring-shaped member to prevent the flow of toner It is valid.

  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. .

  SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and a purpose of the present invention is a cleaning device that can stir toner and prevent its solidification with a simple configuration without requiring a dedicated drive mechanism. The present invention provides an image forming apparatus including the above.

In order to achieve the above object, the invention according to claim 1 comprises a housing in which 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 rotatably accommodated in the housing. In the cleaning device, a spring-shaped member that agitates the toner and contacts the rubbing roller to rotate and is prevented from solidifying is disposed between the inner wall of the housing and the rubbing roller. .

According to a second aspect of the present invention, in the first aspect of the present invention, a plurality of the spring-shaped members are arranged in the axial direction of the rubbing roller.

A third aspect of the invention is characterized in that, in the first or second aspect of the invention, the spring-shaped member is constituted by a coil spring .

  According to a fourth aspect of the present invention, there is provided an image carrier for forming a latent image, a developing device for developing the latent image formed on the image carrier as a toner image, and a toner image on the image carrier on a recording material. 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; and a toner image 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 spring-shaped member agitates the toner by being in contact with the rubbing roller and driven to rotate, a dedicated drive mechanism for rotating the spring-shaped member becomes unnecessary. The toner can be agitated with a simple structure to prevent the toner from solidifying, and the toner can be smoothly discharged to obtain a stable cleaning performance.

According to the second aspect of the present invention, since a plurality arranged spring-shaped member in the axial direction of the rubbing roller, can be rotated stably by a driven each spring-shaped member to the rotation of the rubbing roller.

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

  According to the fourth aspect of the present invention, the toner scraped off from the surface of the image carrier by the rubbing roller in the cleaning device can be stirred and discharged smoothly with a simple configuration. Can be done.

  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 devices 6a to 6d 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 6a, a cylindrical rubbing roller 20 that is long in the direction perpendicular to the paper surface of FIG. 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. A sweep roller 24 having an elliptical cross section that is long in the direction perpendicular to the paper surface of FIG. 2 is rotatably disposed in the toner discharge path in the vicinity of the toner conveying screw 23. 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.

  As shown in FIGS. 2 and 4, the toner discharge path below the spring-shaped member 26 in the housing 21 has a spring shape as a cylindrical rotating body that abuts on the sweep roller 24 and rotates. A member 27 is arranged. 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. The photosensitive drum 2a rotates with a predetermined linear velocity difference in the direction of the arrow (clockwise) in FIG. 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-shaped member 27 contacts 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 immobilization. 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 by the rotating toner conveying screw 23 in the direction perpendicular to the paper surface of FIG. Is collected as waste toner. The toner adhering to the outer peripheral surface of the sweep roller 24 is removed by the sheet 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 these spring-shaped members 26 and 27 is not required, and the toner can be stirred and prevented from solidifying with a simple configuration, and the toner can be discharged smoothly. And cleaning performance can be obtained stably.

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 discharge Roller pair 16 Registration roller pair 17 Fixing device 17a Fixing roller 17b Pressure roller 18 Paper discharge roller pair 20 Rub roller 21 Cleaning device housing 22 Roll plate 22a Arc curved surface portion of roll plate 23 Toner conveying screw 24 Sweep roller 25 Sheet 26 , 27 Spring-shaped member 30 Image reading device 31 Document table glass 32 Exposure lamp 33 Mirror 34 Lens 35 Full color sensor P Recording material

Claims (4)

In a cleaning device in which a rubbing roller that contacts an image carrier and rotates with a linear velocity difference with respect to the image carrier surface is rotatably accommodated in the housing.
A cleaning device comprising: a spring-shaped member disposed between the inner wall of the housing and the rubbing roller, which agitates the toner by abutting against the rubbing roller and rotating the toner to prevent the toner from solidifying .
The cleaning device according to claim 1, wherein a plurality of the spring-shaped members are arranged in an axial direction of the rubbing roller.
The cleaning device according to claim 1, wherein the spring-shaped member is a coil spring .
  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 4. 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