JP5277653B2 - Fixing apparatus and image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a cleaning device, the size of which is prevented from increasing by winding with the density of cleaning web enhanced, and to provide an image forming apparatus. <P>SOLUTION: The cleaning device cleans a fixing roller 31 by means of the cleaning web 44, wherein a take-up shaft 43 is driven rotationally, as well as, the cleaning web 44 is taken up, and a cleaning roller 45 for cleaning the surface of the cleaning web is firmly pressed against the take-up shaft 43, with the cleaning web 44 between them. <P>COPYRIGHT: (C)2009,JPO&amp;INPIT

Description

  The present invention relates to a fixing device including a cleaning device that cleans a peripheral surface of a fixing member with a cleaning web, and an image forming apparatus such as a copying machine, a printer, a facsimile, or a multifunction machine having at least two functions thereof.

  In an image forming apparatus using an electrophotographic process, an electrostatic latent image obtained by irradiating image information onto a uniformly charged photoreceptor is developed with toner supplied from a developing device, and this toner After the image is transferred onto the recording paper, it is fixed on the recording paper by applying pressure while heating by a fixing device. At this time, after the toner image is fixed on the recording paper, the residual toner of the toner image adheres to the surface of the fixing roller as a fixing member, which causes an offset. Therefore, it is necessary to remove the residual toner, and various methods have been proposed.

JP 2002-189374 A JP 2000-315032 A

  Patent Document 1 discloses an image formation in which a toner image is fixed by passing a fixing roller having a heat source therein, a pressure roller in pressure contact with the fixing roller, and a transfer paper holding an unfixed image in its nip portion. A fixing device of the apparatus and a cleaning device that contacts the fixing roller of the fixing device and cleans deposits on the surface of the fixing roller and applies oil for preventing offset are disclosed. The cleaning device includes a cleaning web, a pressing roller for pressing the cleaning web against the heating roller, a winding roller for winding the used cleaning web, a driving unit (not shown), and an unused cleaning web. An unwinding roller is provided that winds and holds the unwinding roller. The cleaning web winding control is to wind the cleaning web intermittently at certain intervals. The relationship between the winding direction of the cleaning web and the rotation direction of the fixing roller is normal and reverse, which cannot be better, but in Patent Document 1, the cleaning web is wound in the reverse direction.

  In a cleaning device using a cleaning web as in Patent Document 1, it is usually assumed that the cleaning web is thickened by cleaning, and the winding shaft side of the cleaning web is finally used up and the winding is completed. It is necessary to design the layout with a certain margin to accommodate a cleaning web having a diameter of. However, in order to reduce the size of the image forming apparatus, it is better that the diameter of the cleaning web to be wound is smaller, and it is desirable that the completion diameter of the winding is close to the winding diameter of the new cleaning web.

  Also, in order to reduce the winding complete diameter as much as possible, a method of increasing the web tension by applying a brake to the winding shaft to increase the cleaning web density on the winding shaft is often used. In the case of the cleaning web, oil impregnated in the cleaning web may be squeezed out by tightening with a tension just before the supply of the cleaning web is completed, and oil leakage may occur. Therefore, a mechanism that minimizes the winding complete diameter without applying a brake to the unwinding shaft is desirable.

  Further, in Patent Document 2, in order to make the cleaning web take-up amount constant even when the winding diameter of the cleaning web gradually increases, a transmission roller is pressed against the outer peripheral surface of the cleaning web, and the rotation of the transmission roller Controls the winding of the cleaning web. This cleaning device seems to be able to increase the density of the cleaning web on the take-up shaft because the cleaning web is sandwiched and taken up by the take-up shaft and the transmission roller.

  However, when the winding shaft is actually free as in Patent Document 2, slack is likely to occur between the winding shaft and the cleaning web. Once slackening occurs, the cleaning web is idled and cannot be wound even when the transmission roller is driven. Furthermore, the dirt adhering to the cleaning web does not adhere to the width direction in a constant manner, and it may sufficiently occur that the dirt adheres to one end side. At this time, the apparatus of Patent Document 2 has a problem that the transmission roller cannot be uniformly pressed over almost the entire width of the outer peripheral surface of the cleaning web, and uneven winding and rotation unevenness of the cleaning web occur.

  SUMMARY OF THE INVENTION An object of the present invention is to provide a fixing device and an image forming apparatus that can solve the above-described conventional problems and prevent the apparatus from being enlarged by increasing the density of the cleaning web and winding it.

In order to achieve the above object, the present invention cleans the surface of the fixing member by slidingly contacting the peripheral surface of the fixing member by the cleaning web fed from the unwinding shaft, and the cleaning web used for the cleaning is taken up by the winding shaft. In the fixing device including a cleaning device that winds up, the cleaning device winds up the cleaning web by rotating the winding shaft, and a roller is brought into contact with the winding shaft with the cleaning web interposed therebetween. The cleaning roller controls the winding of the cleaning web by detecting the position of the roller, detects the fullness of the cleaning web wound around the winding shaft, and the cleaning roller cleans the surface of the cleaning web. A fixing device is proposed.

In order to achieve the above object, the present invention proposes an image forming apparatus comprising the fixing device according to claim 1 .

  According to the configuration of the present invention, the cleaning web can be wound at a high density, and the increase in the winding diameter of the cleaning web can be prevented, thereby contributing to downsizing of the fixing device, and thus the image forming apparatus. Can do.

Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.
FIG. 1 is a schematic configuration diagram of an image forming apparatus showing an embodiment of the present invention. The image forming apparatus of the present embodiment is a color printer (hereinafter referred to as “printer”) that can form a full-color image by adopting an electrophotographic tandem method. The image forming apparatus is not limited to color but may be monochrome, and is not limited to the printer shown in FIG. 1, and may be a copying machine, a facsimile machine, or the like.

The basic configuration and operation of the printer will be described with reference to FIG. 1, and then the configuration and operation unique to the present embodiment will be described.
The printer shown here has a configuration in which a paper feed cassette 2 in which a transfer paper 19 as a recording material is stored is disposed below the image forming apparatus main body 1 serving as a base, and an image forming section is disposed above the cassette. It has become. The image forming unit includes an image forming unit 8 including four image forming units 8Y, 8C, 8M, and 8K as a plurality of image forming units including an image carrier, a plurality of rollers 4, 5, 6; An intermediate transfer unit 7 having an intermediate transfer belt 3 as an intermediate transfer member constituted by a flexible endless belt wound around these rollers, and an optical writing unit that performs optical writing on each image carrier An optical writing unit 15 and a fixing device 30 for fixing the toner image on the transfer paper 19 are provided. The image forming units 8Y, 8C, 8M, 8K and the intermediate transfer unit 7 are detachable from the apparatus main body 1.

  The space between the roller 4 and the roller 5 of the intermediate transfer belt 3 corresponds to the lower belt running side of this belt. In the intermediate transfer belt 3, a secondary transfer roller 20 serving as a secondary transfer device is disposed at a portion facing the roller 6 so as to face the conveyance path R, and a belt for cleaning the belt surface at a portion facing the roller 4. A cleaning device 21 is provided.

  The image forming unit 8 is disposed below the intermediate transfer belt 3 by being disposed so as to face the lower running side. Each image forming unit includes a photosensitive drum 10 as an image carrier in contact with the intermediate transfer belt 3. Around each photosensitive drum 10, a charging device 11, a developing device 12, and a cleaning device 13 are arranged. Transfer rollers 14 as transfer means for performing primary transfer are provided inside the intermediate transfer belt 3 at positions where the respective photosensitive drums 10 are in contact with the intermediate transfer belt 3.

  In the present embodiment, the image forming units 8Y, 8C, 8M, and 8K are basically configured in the same structure. In FIG. 1, only the configuration of the image forming unit 8K is represented by a reference numeral. The difference in each image forming unit is only the color of toner as a developer stored in each developing device 12. The developing devices 12 of the image forming units 8Y, 8C, 8M, and 8K store yellow, cyan, magenta, and black toners, respectively. When the toner is reduced, each developing device 12 is supplied with replenishing toner from toner replenishing bottles T1, T2, T3, and T4 disposed on the upper portion of the apparatus main body 1, respectively.

  The optical writing unit 15 irradiates the surface of each photoconductive drum with the light-modulated laser light L to form a latent image for each color on the photoconductive surface. In the present embodiment, the image forming unit 8 It is arranged below.

  The toner supply bottles T1, T2, T3, T4, the intermediate transfer unit 7, the image forming unit 8, and the optical writing unit 15 are disposed in the apparatus main body 1 so as to be inclined in the same direction. The installation area is reduced compared to the case where it is horizontally arranged in 1.

  When the image forming operation is started, the photosensitive drums 10 of the respective image forming units 8 are rotationally driven clockwise by a driving device (not shown), and the surface of each photosensitive drum is uniformly made to have a predetermined polarity by the charging device 11. Charged. The surface of each charged photosensitive drum is irradiated with laser light from the optical writing unit 15 to form an electrostatic latent image on each surface.

  At this time, image information to be exposed on each photosensitive drum is single-color image information obtained by separating a desired full-color image into color information of yellow, cyan, magenta, and black. The electrostatic latent image formed in this way is visualized as a toner image by the toner of each developing device 12 when passing between each photoconductor and the developing device 12.

  Among the plurality of rollers 4, 5, and 6 around which the intermediate transfer belt 3 is wound, one roller is rotationally driven counterclockwise by a driving device (not shown), whereby the intermediate transfer belt 3 is counterclockwise indicated by an arrow. Driven in the clockwise direction, the other rollers are driven to rotate. The yellow toner image formed by the image forming unit 8Y including the developing device 12 having yellow toner is transferred to the intermediate transfer belt 3 traveling in this way by the transfer roller 14.

  A cyan toner image formed by the image forming units 8C, 8M and 8K, a magenta toner image and a black toner image are successively transferred onto the transferred yellow toner image by the transfer roller 14, and the intermediate transfer belt 3 is thus transferred. Carries a full-color toner image on its surface.

  Residual toner adhering to the surface of each photosensitive drum after the toner image is transferred is removed from the surface of the photosensitive drum by each cleaning device 13, and then the surface is subjected to a static eliminating action by a static eliminating device (not shown). The surface potential is initialized and prepared for the next image formation.

  The transfer paper 19 fed from the paper feed unit 2 is sent to the transport path, and the paper feed timing is measured by the registration roller pair 24 disposed on the paper feed side upstream of the secondary transfer roller 20. The roller 6 and the secondary transfer roller 20 are fed to a facing portion. At this time, a transfer voltage having a polarity opposite to the toner charging polarity of the toner image on the surface of the intermediate transfer belt is applied to the secondary transfer roller 20, whereby the toner image on the surface of the intermediate transfer belt 3 is transferred onto the transfer paper 19. Are collectively transferred.

  The transfer paper 19 onto which the toner image has been transferred is conveyed to the fixing device 30, and when passing through the fixing device 30, heat and pressure are applied to melt and fix the toner image. The transfer sheet 19 on which the toner image has been fixed is located at the end of the transport path, is transported to a discharge unit 23 configured by the upper part of the apparatus main body 1, and then to a stacking unit 25 configured at the upper part of the apparatus main body 1. Discharged. After the toner image is transferred to the transfer paper 19, the toner remaining on the belt is removed from the cleaning device 21 by the intermediate transfer belt 3.

  The above description is an image forming operation when a full-color image is formed on the transfer paper 19, and a single-color image is formed by using any one of the image forming units of the image forming unit 8 or two colors. Alternatively, a three-color image can be formed. When monochrome printing is performed using the printer of this embodiment, an electrostatic latent image is formed only on the photosensitive drum of the image forming unit 8K, developed by the unit, transferred to the transfer paper 19, Fixing may be performed by the fixing device 30.

FIG. 2 is a schematic configuration diagram showing the configuration of the fixing device 30.
In FIG. 2, the fixing device 30 of this embodiment includes a fixing roller 31 heated by a heater 33 as a pair of fixing members, and a pressure roller 32 pressed against the fixing roller 31. A separation claw 34 for preventing the transfer paper 19 from being wound, a temperature sensor 35 for detecting the surface temperature of the fixing roller, and a cleaning device 40 for removing dirt on the surface of the fixing roller are arranged. The fixing roller 31 is rotationally driven in a counterclockwise direction by a driving device (not shown), whereby the pressure roller 32 is driven to rotate in the clockwise direction. When the transfer paper 19 carrying the toner image is sandwiched between the rotating fixing roller 31 and the pressure roller 32, the toner image is melted by the action of heat and pressure and fixed on the surface of the transfer paper 19. Is done. Reference numeral 36 denotes an inlet guide, and 37 denotes an outlet guide.

  When such a fixing operation is performed, the toner image of the transfer paper is in contact with the fixing roller 31, so various measures are taken on the surface of the fixing roller 31 to reduce the toner transfer. However, a slight transfer of toner to the fixing roller 31 is unavoidable, and when the amount of transferred toner increases, the toner may re-attach to the surface of the transfer paper 19 to contaminate the transfer paper 19 and deteriorate the image quality. There is. Therefore, the toner transferred to the fixing roller 31 is removed by the cleaning device 40.

  2 and 3, the cleaning device 40 is rotatably supported, and an unwinding shaft 41 around which a flexible cleaning web 44 is wound, and a pressing roller that presses the fed cleaning web 44 against the fixing roller 31. 42 and a take-up shaft 43 for taking up the fed cleaning web 44. The unwinding shaft 41, the pressing roller 42, and the winding shaft 43 are rotatably supported by a side plate (not shown) such as the fixing device 30.

  The cleaning web 44 can be made of an appropriate material such as cloth, paper, resin sheet, resin film, or metal foil. In the illustrated example, the cleaning web 44 is in sliding contact with the peripheral surface of the fixing roller 31 and the peripheral surface is The cleaning web 44 is made of a non-woven fabric formed by mixing a material that can be impregnated with oil, for example, aramid and PET fibers. When the cleaning web 44 comes into sliding contact with the peripheral surface of the fixing roller 31, the oil impregnated therein is thinly and uniformly applied to the peripheral surface of the fixing roller. As this oil, an oil that makes it difficult for toner to transfer to the peripheral surface of the fixing roller 31, enhances the lubricity of the peripheral surface, and prevents wear of the peripheral surface is used.

  One end of the cleaning web 44 is fixed to the winding shaft 43, and one end of the shaft is drivingly connected to a driving device (not shown) via a gear or the like. In order to make the diameter of the cleaning web 44 wound around the take-up shaft 43 as small as possible, the density of the cleaning web 44 on the take-up shaft 43 is increased, and the dirt adhering to the surface of the cleaning web 44 is wiped off. It is requested to take.

  Therefore, in the cleaning device 40 of the present embodiment, a roller configured as a cleaning roller 45 that is in contact with the winding shaft 43 and the cleaning web 44 to be wound is provided, and the roller is more releasable than the cleaning web 44. A bad thing, for example, a metal roller, is used to remove dirt adhered to the surface of the cleaning web 44. The cleaning roller 45 shown in FIG. 3 is arranged almost directly above the take-up shaft 43, that is, arranged so that the take-up shaft 43 is positioned almost directly below the cleaning roller 45 in the vertical direction, and cleaning is performed by its own weight. It is in contact with the web 44. At this time, the cleaning roller 45 is preferably brought into pressure contact with the cleaning web 44. Therefore, the cleaning roller 45 may be made of a material made of a metal having a large specific gravity or a weight or the like disposed inside. It is advantageous.

  The shaft 46 of the cleaning roller 45 is inserted into a vertical groove hole 48 formed in the guide member 47, whereby the cleaning roller 45 is mounted so as to be movable only in the vertical direction along the vertical groove hole 48. .

  In the cleaning device 40 configured in this manner, the cleaning web 44 wound around the winding shaft 43 is wound with a higher density without being loosened by the cleaning roller 45. Further, dirt such as residual toner adhering to the surface of the cleaning web 44 is transferred to the cleaning roller 45 and the cleaning web 44 is cleaned. Therefore, the winding diameter of the cleaning web 44 can be made as small as possible, and the space for storing the wound cleaning web 44 can be small. That is, in the cleaning device 40 of this embodiment, if the cleaning web 44 is wound around the winding shaft 43 while being in close contact with the cleaning roller 45, and if the cleaning web 44 is wound while the dirt is attached, dirt such as residual toner is collected. The winding diameter is increased by this thickness, but by removing the dirt attached to the cleaning web 44 by the cleaning roller 45, the winding diameter can be made extremely small.

  By the way, the cleaning device 40 makes the cleaning roller 45 come into contact with the take-up shaft 43 through the cleaning web 44 by its own weight, but a certain amount of contact pressure is required to make the cleaning web 44 adhere well. For this reason, as described above, the cleaning roller 45 is restricted by being made of a material made of a metal having a high specific gravity or having a weight or the like disposed inside.

  Therefore, the cleaning roller 45 may be brought into contact with the cleaning web 44 not by its own weight but by using an elastic means such as a spring. With such a configuration, restrictions on the material and configuration of the cleaning roller 45 can be relaxed, and the direction in which the cleaning web 44 is pressed against the cleaning web 44 can be set to any direction other than directly above.

  Further, although the cleaning roller 45 of the above embodiment is constituted by a driven roller, the cleaning roller 45 may be a driving roller that is rotated by a driving source. At this time, the cleaning roller 45 is set in a counter direction with respect to the winding direction of the cleaning web 44. When the cleaning web 44 is rotated, the cleaning web 44 is wound up so that the density of the wound cleaning web 44 can be increased.

  The cleaning device 40 controls to wind up the cleaning web 44 by a predetermined amount every predetermined number of image formations. However, when the cleaning web 44 is wound by rotating the winding shaft 43 by a certain rotation angle, Since the winding amount increases in proportion to the diameter of the cleaning web 44 on the take-up shaft 43, a certain amount of winding cannot be performed.

  Therefore, in the present invention, when the cleaning roller 45 is a driven roller, the rotation of the cleaning roller 45 and the amount of winding of the cleaning web 44 are constant even if the diameter of the cleaning web 44 on the winding shaft 43 changes. The rotation of 45 is detected and the winding of the cleaning web 44 is controlled. Specifically, a means for detecting the rotation of the shaft 46 of the cleaning roller 45 is provided, and the drive of the winding shaft 43 is controlled from the signal of the detecting means so that the winding linear velocity is constant.

  Further, in order to make the winding speed of the cleaning web 44 constant, the position of the cleaning roller 45 may be detected to perform winding control. That is, the diameter of the cleaning web 44 taken up from the position of the cleaning roller 45 can be calculated, and the drive of the take-up shaft 43 may be controlled from the diameter.

  Further, when the position of the cleaning roller 45 is detected, the fullness of the cleaning web 44 can be detected. That is, when the web roller can be fully recognized by detecting the position of the cleaning roller 45, the space of the fixing device 30 can be wound up.

  As mentioned above, although preferable embodiment of this invention was described, this invention should not be limited only to the said embodiment. For example, the fixing device of the above embodiment is a roller fixing device including a fixing roller and a pressure roller, but may be other types of fixing devices such as a belt fixing device using a fixing belt. The fixing member cleaned by the cleaning device is not limited to the fixing roller, and may be a pressure roller, a fixing belt, or the like.

It is a schematic sectional drawing which shows an example of an image forming apparatus. 1 is a configuration diagram of a fixing device provided with a cleaning device according to the present invention. 1 is a perspective view of a fixing device including a cleaning device according to the present invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 30 Fixing device 31 Fixing roller 40 Cleaning device 41 Unwinding shaft 42 Pressing roller 43 Winding shaft 44 Cleaning web 45 Cleaning roller

Claims (2)

In a fixing device provided with a cleaning device that cleans the surface of the fixing member by sliding on the peripheral surface of the fixing member by a cleaning web fed from a winding shaft, and winding the cleaning web used for the cleaning around the winding shaft.
The cleaning device is configured such that the cleaning web is wound by rotating the winding shaft, and a roller is brought into contact with the winding shaft with the cleaning web interposed therebetween,
Detecting the position of the roller to control the winding of the cleaning web, and detecting the fullness of the cleaning web wound around the winding shaft,
The fixing device, wherein the roller is a cleaning roller for cleaning a surface of a cleaning web . An image forming apparatus comprising the fixing device according to claim 1 .

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