JPH01179978A - Photosensitive body cleaning device - Google Patents

Abstract

PURPOSE:To prevent stain around an image forming body and to obtain an image having good quality for a long period by applying a voltage to a conductive sheet stuck to a cleaning blade to drop toner, which is scraped from the surface of a photosensitive body by the cleaning blade, with electric repulsion. CONSTITUTION:A conductive sheet 10 stuck to the surface of a cleaning blade 2 which forms a wedge-shaped space part together with a photosensitive body 1, and an AC voltage is applied to this sheet 10. The cleaning blade 2 is pressed to the photosensitive body 1 by the operation of a holding device just before transferred remaining toner reaches a position facing the cleaning blade 2, and remaining toner is peeled from the surface of the photosensitive body 1 by the cleaning blade 2 and is separated from the cleaning blade 2 by the electric repulsion of the conductive sheet 10 and is led into a groove in the lower part of a casing 22. Thus, a toner reservoir at the cleaning point is eliminated and the image having high quality is obtained for a long period.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a cleaning device for a photoconductor of an electrophotographic apparatus, and more particularly to a photoconductor cleaning device of a type in which a cleaning blade is brought into pressure contact with a rotating photoconductor.

[Prior Art] Conventionally, as a means for cleaning toner after transfer from an image forming body, that is, a photoreceptor, of an electrophotographic apparatus, a blade cleaning method, which has a simple structure and has high cleaning efficiency, has been used. FIG. 3 is a diagram schematically showing the blade cleaning method.

In the figure, 1 is a cylindrical photoreceptor that rotates in the direction of the arrow. 2 is a cleaning blade made of polyurethane or the like, and 3 is a toner collection roller.

During cleaning, the cleaning blade 2 advances to the right in the figure, brings the end corner into contact with the surface of the photoreceptor 1 as shown by the dotted line, and cleans by scraping off the toner remaining on the surface. Toner image in progress (first color toner image,
When toner images of the second color, etc.) pass, these toner images must not be disturbed, so they are retracted to the position shown by the solid line.

During cleaning, the toner scraped off by the cleaning blade 2 falls downward and is collected by a toner collection roller 3 located below toward a toner pool.

However, in such a configuration, when the cleaning blade 2 is retracted, a portion of the toner scraped up by the cleaning blade 2 may pass through the cleaning device while remaining attached to the photoreceptor 1, or
Toner that is being written down and falling by the cleaning blade 2 often adheres to the surface of the photoreceptor 1 between the position where the cleaning blade 2 was in contact and the position facing the toner collection roller, and the cleaning blade 2 is retracted. Due to this condition, cleaning defects may occur where the particles pass through the cleaning device without being scraped off.

In this way, the toner that has not been completely erased moves with the rotation of the photoreceptor 1 and spreads to other parts of the photoreceptor surface, or is scattered, and the toner disposed around the photoreceptor 1 is damaged by the charger and developer. This may stain peripheral equipment such as containers, transfer devices, and separators, thereby hindering the formation of high-quality images.

Therefore, the inventors of the present invention have invented a means for cleaning the toner that has slipped through without being scraped off by the cleaning blade 2 during the retracting operation of the cleaning blade 2, and the present applicant is currently applying for a patent. (Patent IXI 60-2
33019 > Figure 4 is a schematic diagram of the invention of the above application.

The difference from FIG. 3 is that a cleaning roller 4 made of sponge is newly provided.

The cleaning roller 4 is made of urethane foam rubber,
Contacting the surface of the photoreceptor 1 while rotating it in the same direction as the rotation direction of the photoreceptor 1 (movements at the contact portion are in opposite directions),
Clean the residual toner that has passed through the cleaning blade 2 by wiping it. Of course, like the cleaning blade 2, this cleaning roller 4 is also retracted when a toner image that is being formed passes therethrough. Toner that has been wiped off by the cleaning roller 4 and adhered to its surface is scraped off by a scraper 5.

The cleaning roller 4 is provided for the above purpose, so that after the cleaning blade 2 is retracted, it comes into contact with the photoreceptor 1 before the accumulated toner adhering to the photoreceptor 1 arrives, and the cleaning blade 2 is retracted. At times, the portion of the photoreceptor 1 facing the toner collection roller 3 continues to be in contact until it passes the cleaning roller 4, and then retreats.

Cleaning roller 4 in an actual image forming apparatus,
Considering the spacing between the cleaning blade 2 and the toner collection roller 3 and the circumferential distance of the photoreceptor 1, the cleaning roller 4 will move onto the photoreceptor 1 immediately after the cleaning blade 2 is retracted.
and will be evacuated in a short period of time.

[Problem to be solved by the invention 1 The above-described cleaning device (Patent Application No. 6O-2330
No. 19) shows the results by thoroughly cleaning the accumulated toner adhering to the photoreceptor when the cleaning blade is retracted.

However, in addition to the toner recovery device from the toner recovery roller, the rock structure becomes complicated because it requires a toner recovery device from the cleaning roller, and space is required to install the cleaning roller downstream of the cleaning blade. Furthermore, there are other problems such as an instantaneous increase in driving load due to the sponge rubber material coming into contact with the surface of the image forming body.

The present invention has been made to solve the above-mentioned problems.The present invention has been made in order to improve the cleaning performance, which is the main function for cleaning toner, in a photoconductor cleaning device having a drum-shaped cleaning blade that is pressed against the circumferential surface of a rotating photoconductor. It is an object of the present invention to provide a cleaning device for a compact image forming apparatus, which can maintain high quality images for a long period of time, prevent staining of various devices installed around an image forming body, and form high quality images for a long period of time. .

[Means for Solving the Problems] In a photoconductor cleaning device having a cleaning blade formed in a drum shape and pressed against the circumferential surface of a rotating photoconductor, the cleaning blade defines a wedge-shaped space with the photoconductor. A conductive sheet is attached to the surface, a power source is provided to apply a voltage to the conductive sheet, and a voltage is applied to the conductive sheet while the cleaning blade is pressed against the photoreceptor.

[Operation] The toner scraped off from the surface of the photoreceptor by the cleaning blade is separated from the cleaning blade and falls due to the electrical repulsion force caused by the voltage applied to the conductive sheet attached to the cleaning blade. Since the photoreceptor is constantly moving, toner is also separated from the photoreceptor, and toner does not accumulate on the photoreceptor and the stool-shaped portion of the cleaning blade.

Therefore, when the cleaning blade leaves the photoreceptor, no toner remains on the photoreceptor or on the cleaning blade, and the area around the image forming member is not contaminated. Further, since toner does not adhere to the cleaning blade for a long period of time, the cleaning performance is maintained stably and high, and high quality images can be obtained for a long period of time.

[Example] Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a sectional view showing the main parts of a color copying machine to which the present invention is applied, and FIG. 2 is an enlarged sectional view showing the cleaning device in FIG. 1 with the drive section removed.

In the figure, reference numeral 1 denotes a photoreceptor made of a photoconductor (OPC) laminated on a cylindrical conductive drum, which forms a color toner image while rotating in the direction of the arrow shown in the figure. That is, the surface of the photoreceptor 1 cleaned by the cleaning device 11 is uniformly charged by the charger 8, and is irradiated with laser light 9 so as to form a charged latent image corresponding to the toner image of each color. is the developing device 12 (13, 14)
attached by. The charging exposure and development described above is repeated once for each color, thus three times for three colors. The above laser exposure is main scanned in the direction perpendicular to the plane of the paper and is combined with sub-scanning by the drum rotation to form charged latent images corresponding to yellow, mapinta, and cyan images on the surface of the photoreceptor. The image information is provided by a conventionally known color separation image reading device and image processing device. In this way, a color toner image is formed on the photoconductor 1. To explain the time course, during the first rotation of the photoconductor 1, a charged latent image corresponding to the yellow toner created by the laser exposure 9 becomes yellow. Toner developing device 12
By applying a direct current to the toner, the yellow toner image is developed by the developing roller 12' and a yellow toner image is formed on the surface of the photoreceptor 1. Similarly, during the second rotation of the photoconductor 1, the photoconductor 1 is
Magenta toner is deposited on the surface of the image. Also, the photoreceptor 3
The developing roller 14 of the cyan toner developing device 14 is located at the rotation point.
- Cyan toner is attached.

The color image thus formed on the surface of the photoreceptor is transferred by a transfer device 16 onto recording paper fed from a paper feeder 15. The transferred recording paper is separated by a separator 17 and then sent to a fixing device 18, where the three-color image is fixed on the recording paper. Since the three-color images are combined on the photoreceptor 1 and transferred onto the recording paper at once, an image of good quality without color shift can be obtained. In the above process, the photoreceptor first passes through the cleaning device 11 while carrying a yellow toner image, and then passes through the cleaning device 11 while carrying yellow toner and magenta toner images. In this way, when an untransferred image passes, the cleaning device 11 is deactivated, and the cleaning device 11 is activated at other times. The cleaning device will be explained below with reference to FIG. Reference numeral 2 denotes a cleaning blade constituting the main cleaning means, which is held by a holding device 20 that is driven to rotate about a shaft 19, and is brought into and out of pressure contact with the photoreceptor 1.

Reference numeral 10 denotes a conductive sheet, which is attached to a surface of the cleaning blade 2 that defines a horizontal space together with the photoreceptor 1, and is adapted to be applied with an alternating current voltage.

Reference numeral 3 denotes a toner collecting roller that constitutes a member, and is arranged with a gab (0) of about 0.2 to 0.3 m between it and the photoreceptor 1, and is driven to rotate in the direction of the arrow, and is also connected to a positive DC current. A crazy 500V is being applied. 6 is a toner guide that guides the toner from above the toner collection roller 3 to the casing 22.
lead to the lower groove. 7 is rotated by a screw so that a spiral blade sends toner into a toner reservoir.

Next, the operation of the cleaning device will be explained. As mentioned above, when an untransferred toner image passes, the cleaning roller does not operate, so the cleaning blade 2 is held at a position separated from the photoreceptor 1. Immediately before the residual toner after transfer reaches a position facing the cleaning blade 2 of the cleaning device, the cleaning blade 2 is pressed against the photoreceptor 1 by the operation of the holding device. This state is maintained throughout the passage of the imaged portion. In this way, the residual toner is peeled off from the surface of the photoreceptor by the cleaning blade 2, separated from the cleaning blade by the electrical repulsion of the conductive sheet, and directed into the lower part of the casing along the path shown by the arrow. That is, since the toner collection roller 3 is applied with a voltage of opposite polarity to the toner, it attracts the toner and does not leak it downward. The toner on the toner collection roller 3 is sent onto the toner guide 6 as the toner collection roller rotates.

The application of voltage to the 12-meter sheet can also be switched on and off according to the process. That is, when the cleaning blade is in pressure contact with the photoconductor, a voltage is applied, and when the cleaning blade is away from the photoconductor, no voltage is applied.

Although the present embodiment uses electric force based on alternating current voltage, the invention is not limited to this, and a combination of direct current and alternating current may be used.

[Effects of the Invention] As explained above, in the cleaning device of the present invention, toner is removed by electrical repulsion in the dendritic space between the cleaning blade and the photoreceptor, which improves the repeatability of the copying process. The toner accumulation at the cleaning point that causes the damage is removed, toner filming and crystallization of paper dust, etc. are prevented, and the length RQ of the cleaning blade as a consumable item is increased and damage to the photoreceptor is reduced. .

Furthermore, in the case of the present embodiment in which the cleaning blade is released from the pressure bond, there is no need to provide a second toner collecting means, resulting in a compact and inexpensive device configuration, and the load on the mechanical drive is also reduced.

In this way, the present invention provides a cleaning device that can obtain high-quality cakes over a long period of time using a conventional blade cleaning method that is simple, highly stable, and has good cleaning efficiency.

[Brief explanation of the drawing]

FIG. 1 is a sectional view showing the main parts of a color copying machine to which the present invention is applied, FIG. 2 is an enlarged sectional view showing the cleaning device 11 in FIG. 1 excluding the drive section, and FIG. FIG. 4 is a cross-sectional view of a conventional cleaning device; FIG. 4 is a cross-sectional view of an improved conventional cleaning device. 1... Photoreceptor, 2... Cleaning blade, 3...
... Toner collection roller, 4 ... Cleaning roller,
5... Scraper, 6... Toner guide, 7...
Screw, 8... Charger, 9... Laser exposure, 1
0... Conductive sheet, 11... Cleaning device,
12...Yellow toner developing device, 15...Paper feeding device, 16...Transfer device, 17...Separation, 18...
Fixing device, 19... shaft, 20... holding device, 22...
·casing. Applicant's agent Hiroshi Fujimoto 15th / Zuo 3 Zujin 4 Deputy

Claims (1)

[Claims] In a photoconductor cleaning device having a cleaning blade formed in the shape of a drum and pressed against the circumferential surface of a rotating photoconductor, a conductive sheet is attached to a surface of the cleaning blade that defines a wedge-shaped space together with the photoconductor. A photoreceptor cleaning device characterized by being provided with a power source for applying voltage to a conductive sheet.