JP2003337517A - Cleaning device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a cleaning device constituted so that the toner removing function of a fur brush can be recovered. <P>SOLUTION: The cleaning device 27 for cleaning the toner sticking on the surface of a transfer belt 26 by the fur brush 28 while rotating the fur brush 28 in contact with the surface of the transfer belt 26, is provided with a scraper 30 coming into contact with the fur brush 28, a toner concentration detection sensor 37 for detecting the toner concentration on the surface of the transfer belt 26, and a controller 34 for rotating the fur brush 28 in a reverse direction when the concentration detected by the toner concentration detection sensor reaches a prescribed value. By scraping up the fiber of the fur brush 28 by the scraper 30 while reversely rotating the fur brush 28 when the toner concentration on the surface of the transfer belt 26 becomes equal to or exceeds the prescribed value, the outside dimension of the fur brush 28 is restored to its original one, and also, the toner sticking to the fur brush 28 is scraped. <P>COPYRIGHT: (C)2004,JPO

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is used for an image forming apparatus such as a copying machine, a printer, a facsimile, and the like, and uses a rotating member such as a photosensitive member or a transfer belt to which toner adheres. The present invention relates to a cleaning device for removing toner. 2. Description of the Related Art An image forming apparatus using an electrophotographic technique transfers a toner image on a photoreceptor to a sheet (paper, plastic sheet, etc.) sent from a sheet supply means by a transfer device, and then transfers the toner image to the sheet. Is heated and pressed by a fixing device to fix the toner on the sheet. FIG. 5 is an enlarged view showing a part of such an image forming apparatus. In the image forming apparatus 1 shown in FIG. 5, a transfer belt 26 wound around a driving roller 21 and a driven roller 22 constitutes a transfer device 10. The transfer is performed by applying a voltage having a polarity opposite to that of the toner from the back surface. The transfer device 10 using such a transfer belt 26 can separate and convey a sheet from the photoreceptor 8 in addition to transfer.
Since the toner adheres to the six surfaces, a cleaning device 40 for removing the toner is used in combination. FIG. 6 shows a cleaning device 40 for removing toner attached to the surface of the transfer belt 26. The cleaning device 40 includes a fur brush 41 that is in rotational contact with the surface of the transfer belt 26 near the driving roller 21 and an auger for toner collection that collects the toner removed by the fur brush 41 into a toner collection tank (not shown). 42, the fur brush 41 and the auger 4
2 and a casing 43 in which a space for accommodating the removed toner is formed. [0008] However, in the fur brush 41 of the cleaning device 40, the thin fibers 41b are bent and deformed by sliding contact with the rotating transfer belt 26, and the entire outer diameter is reduced. With sufficient pressure, contact with the transfer belt 26 becomes difficult. As a result, there is a problem that the effect of removing the toner by the fur brush 41 gradually decreases with time. Such a problem also exists in a fur brush or the like of a cleaning device used for removing toner from a photoconductor. Accordingly, an object of the present invention is to provide a cleaning device capable of restoring the toner removing function of a fur brush. According to a first aspect of the present invention, there is provided a cleaning device for bringing a fur brush into rotational contact with a surface of a rotating body to remove toner adhering to the surface of the rotating body with the fur brush. A scraper for contacting the fur brush, a toner concentration detecting sensor for detecting a toner concentration on the surface of the rotating body, and control means for rotating the fur brush in a reverse direction when the detected concentration of the toner concentration detecting sensor reaches a predetermined value. And, it is characterized by having. According to the present invention having such a configuration, when the fur brush is reduced in diameter due to rotational contact with the rotating body and the toner removing performance of the fur brush is reduced, the amount of toner adhering to the rotating body surface increases. Therefore, the toner density on the surface of the rotating body is detected by the toner density detection sensor, and when the detected density reaches a predetermined value, the fur brush is rotated in the reverse direction to scrape the fibers of the fur brush with the scraper. As a result, the outer diameter of the fur brush is restored to the original size, the toner attached to the fur brush is knocked down, and the toner removing performance of the fur brush is restored. Embodiments of the present invention will be described below in detail with reference to the drawings. [First Embodiment] FIG. 1 shows a schematic configuration of an image forming apparatus 1 showing an embodiment of the present invention. As shown in FIG. 1, the sheet 3 stacked on the sheet feed tray 2 is sent to the nip portion between the feed roller 5 and the reverse roller 6 by the pickup roller 4, and only one sheet is separated and the registration roller pair 7 is separated. Transported to The registration roller pair 7 feeds the sheet 3 between the photoconductor 8 and the transfer device 10 so that the front end of the toner image on the photoconductor 8 and the front end of the sheet match. Then, the toner image on the photoconductor 8 is transferred to the sheet sent between the photoconductor 8 and the transfer device 10. Here, a cleaning device 11, a charging device 12, a developing device 13, and an optical unit 14 are arranged around the photoconductor 8. The sheet on which the toner image has been transferred is a heating roller 16 and a pressure roller 17 which constitute a fixing device 15.
And heated and pressed by the heating roller 16 and the pressing roller 17. As a result, the toner image is fixed on the sheet. Then, the sheet 3 that has passed through the fixing device 15 is discharged onto a discharge tray 20 by a discharge roller pair 18. The transfer device 10 includes a driving roller 21, a driven roller 22, a transfer roller 23, and a support roller 2.
4, 25 and a transfer belt (rotating body) 26 made of an elastic material and wound around these rollers. Then, the transfer device 10 applies a voltage having a polarity opposite to that of the toner on the photoconductor 8 to the transfer roller 23, and the transfer belt 26
The transfer is performed by giving a charge to the sheet via the. In such a configuration of the transfer device 10, since the toner adheres to the transfer belt 26, a cleaning device 27 for removing the toner adhered to the transfer belt 26 is arranged near the drive roller 21. FIG. 2 shows a first example of the cleaning device 27.
It is an enlarged view which shows embodiment. The cleaning device 27 includes a fur brush 28, a scraper 30, an auger 31, and a casing 32. The fur brush 28 includes a rotating shaft 2
A thin fiber 28b made of resin is planted around 8a, and comes into rotational contact with the transfer belt 26 in a state where the fiber 28b is bent and deformed (hair falls). The fur brush 28 has a rotating shaft 28a that is
3 is controlled by a controller (control means) 34 electrically connected to the motor 33. Here, the fur brush 28 rotates in the same direction as the rotation direction of the transfer belt 26 during normal printing, but rotates in the opposite direction during maintenance of the fur brush described later. When the speed (V1) of the transfer belt 26 and the speed (V2) of the outer periphery of the fur brush 28 are the same (V1 = V2), the relative speed when the fur brush 28 slides on the transfer belt 26 is 2 · V1. Become. As a result, the fur brush 28 and the transfer belt 26 rub at a high speed, and the toner on the transfer belt 26 adheres to the tip of the frictionally charged fur brush 28, and the toner on the transfer belt 26 is mechanically removed. The scraper 30 has a tip 30a.
Is arranged at a position where it comes into contact with the fiber 28b of the fur brush 28, and its base 30b is fixed to the mounting portion 32a of the casing 32 with screws or the like. Then, as shown in FIG. 3, when the fur brush 28 rotates in the opposite direction (clockwise direction in the figure), the scraper 30
In addition to scratching the back surface of the bent and deformed fiber 28b, the toner attached to the fiber 28b can be knocked down. As a result, the fur brush 28 has the fibers 28b stretched, the outer diameter dimension returns to the original state, and the fur brush 28 can contact the transfer belt 26 with sufficient pressure, and the toner removing function is restored. The auger 31 transports the toner scraped from the transfer belt 26 by the fur brush 28 to a toner collection container (not shown). The casing 32 comprises a fur brush 28
And the auger 31 are rotatably accommodated, and the fur brush 28 does not leak toner scraped off from the transfer belt 26 to the outside. Here, as shown in FIG. 1, a sheet detection sensor 36 that detects the passage of the sheet 3 and outputs a detection signal to the controller 34 is disposed in the sheet conveyance path 35. At a position downstream of the fur brush 28, that is, at a position facing the outer surface of the transfer belt 26 on the driven roller 22 side, a toner density detection sensor for detecting the density of toner adhering to the outer surface of the transfer belt 26. 37 are arranged. The toner concentration detection sensor 37 outputs the detection signal to the controller 34. FIG. 4 is a flowchart showing the state of controlling the rotation of the fur brush 28. First, the sheet transport path 3
When the number of sheets passing through No. 5 reaches a predetermined number (N), that is, when the number of printed sheets reaches N (S1), the controller 34 drives the motor 33 based on a detection signal from the sheet detection sensor 36. As shown in FIG. 3, the fur brush 28 is rotated in a direction opposite to the rotation direction at the time of toner removal (S3). As a result, the fallen fibers 28b of the fur brush 28 are scraped by the scraper 30, and the toner attached to the fur brush 28 is removed by the scraper 3.
At 0, the fur brush 28 is restored to its original outer diameter and the toner removal function of the fur brush 28 is restored. Then, when the fur brush 28 rotates in the reverse direction for a predetermined time (S4), the controller 33 stops the motor 33 and stops the function recovery work of the fur brush 28. Also, even if the number of prints has not reached N,
If the result detected by the toner concentration detection sensor 37 is equal to or greater than a predetermined value (S2), that is, if the transfer belt 26 is soiled with toner equal to or greater than the predetermined value, the controller 34 drives the motor 33 to cause the fur brush 28 to It is rotated in the direction opposite to the rotation direction at the time of removal (S3). As a result, the toner removing function of the fur brush 28 is restored. Then, when the fur brush 28 rotates in the reverse direction for a predetermined time (S4), the controller 34 stops the motor 34 and stops the recovery work of the function of the fur brush 28. The above-described function recovery operation of the fur brush 28 is performed after a series of printing operations is completed. According to the present embodiment having the above-described configuration, even if the fur brush 28 comes into contact with the surface of the transfer belt 26 and the hair falls down, the fur brush 28
Is rotated in a direction opposite to the rotation direction at the time of toner removal, so that the fibers 28b of the fur brush 28 are scraped by the scraper 30.
And the outer diameter of the fur brush 28 can be restored, and the toner attached to the fur brush 28 can be knocked down. Therefore, according to the present embodiment, the toner removing function of the fur brush 28 can be maintained for a long time. In the above embodiments, the cleaning device 27 is used to remove the toner from the transfer belt 26. However, the present invention is not limited to this.
8 can be used as the cleaning device 11 for removing the toner. Further, when an intermediate transfer member is used, it can be used for removing toner from the intermediate transfer member. That is, the cleaning device 2 of the present invention
Numeral 7 can be widely applied for removing toner attached to the surface of the rotating body. According to the present invention, when the toner concentration on the surface of the rotating body becomes a predetermined value or more, the fur brush is rotated in the reverse direction so that the fibers of the fur brush are scraped by the scraper, and the outer diameter of the fur brush is reduced. Since it can be restored to the size of and the toner attached to the fur brush can be knocked down, the toner removal function of the fur brush can be restored,
The toner removal function of the fur brush can be maintained for a long time.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic configuration diagram of an image forming apparatus according to an embodiment of the present invention. FIG. 2 is a first operation state diagram of the cleaning device according to the embodiment of the present invention. FIG. 3 is a second operation state diagram of the cleaning device according to the embodiment of the present invention. FIG. 4 is a flowchart illustrating an operation control state of the cleaning device. FIG. 5 is a schematic configuration diagram of a conventional image forming apparatus. FIG. 6 is a configuration diagram of a conventional cleaning device. DESCRIPTION OF SYMBOLS 1... Image forming apparatus, 3... Sheet, 8... Photosensitive member (rotating body), 11... Cleaning device 26... Transfer belt (rotating body) 27. 28 ...
... fur brush, 30 ... scraper, 34 ... controller (control means), 35 ... sheet transport path, 36 ...
Sheet detection sensor, 37: toner concentration detection sensor

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Claims (1)

1. A cleaning device for rotating a fur brush on a rotating body surface to remove toner adhering to the rotating body surface with the fur brush, wherein the scraper is in contact with the fur brush. A toner concentration detection sensor for detecting the toner concentration on the surface of the rotating body; and control means for rotating the fur brush in a reverse direction when the detection concentration of the toner concentration detection sensor reaches a predetermined value. Cleaning device.