JPH01179979A - Photosensitive body cleaning device - Google Patents

Abstract

PURPOSE:To prevent stain around an image forming body and to obtain an images having good quality for a long period by applying a voltage to a conductive wire arranged in the vicinity of the tip end of 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 wire 10 is stretched between supporting bodies 23 and 23 stuck to both ends of a holding device 20 in the vicinity of the contact between a cleaning blade 2 and a photosensitive body 1, and an AC voltage is applied to the wire 10. The cleaning blade 2 is pressed to the photosensitive body 1 by the operation of the 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 wire 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 particularly relates 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, a blade cleaning method, which has a simple structure and high cleaning efficiency, has been used as a means for cleaning toner after transfer from an image forming body, that is, a photoreceptor, of an electrophotographic apparatus. There is. 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 row.

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

At one time, the toner scraped off by the cleaning blade 2 falls downward and is collected by the toner collection roller 3 located below toward the 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.
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.

The toner that could not be completely cleaned moves with the rotation of the photoconductor 1 and spreads or scatters to other parts of the photoconductor surface, causing the charger and developer disposed around the photoconductor 1 to be damaged. This may stain peripheral equipment such as a transfer device and a separator, thereby hindering the formation of high-quality images.

Therefore, the inventors of the present invention have invented a means for cleaning the toner that is not scraped off by the cleaning blade 2 during the retracting operation of the cleaning blade 2, and the applicant of the present application is currently applying for a patent. (Special application 1986-2330
19> FIG. 4 is a schematic diagram showing the invention of the above application.

The difference from FIG. 3 is that a sponge cleaning roller 4 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),
Dip the cleaning blade 2 to wipe off the residual toner. 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 row 54 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 using the toner recovery roller, the mechanism becomes complicated due to the provision of a toner recovery device based on the cleaning roller, and the need for space to dispose the cleaning roller downstream of the cleaning blade. Further, there were other problems such as an instantaneous increase in driving load due to the sponge rubber material coming into contact with the surface of the thin molded body.

The present invention has been made in order to solve the above-mentioned problems.In a photoconductor cleaning device having a drum-shaped cleaning blade that is pressed into contact with the surface of a rotating photoconductor, the present invention maintains cleaning performance, which is the main function for toner, for a long period of time. To provide a cleaning device for a compact image forming apparatus, capable of maintaining high quality images for a long period of time, preventing staining of various devices provided around an image forming body, and forming high quality images for a long period of time.

[Means for Solving the Problems] In a photoconductor cleaning device having a drum-shaped cleaning blade that is brought into pressure contact with the surface of a rotating photoconductor, the photoconductor movement direction near the contact point between the cleaning blade and the photoconductor is provided. A conductive wire is disposed in front, and a power source is provided to apply a voltage to the conductive wire, and the voltage is applied to the conductive wire when the cleaning blade is pressed onto 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 wire placed near the tip of 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 horizontal 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 shown in FIG. 1 with the drive section removed.

In the figure, reference numeral 1 denotes a photoreceptor made of an organic optical semiconductor (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. Developed image 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 paper surface and combined with sub-scanning by drum rotation to form charged latent images corresponding to yellow, magenta, and cyan images on the photoreceptor surface, but the laser exposure is modulated. The image information for this purpose 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 photoreceptor 1, the developing roller 13- of the magenta toner image device 13 rotates the photoreceptor 1.
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, a good image 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.

A conductive wire 10 is stretched between supports 23 and 23 fixed to both ends of the holding device 2o in the vicinity of the contact point between the cleaning blade 2 and the photoreceptor 1.
An alternating current voltage of 0V is applied.

The toner receiver 3 is arranged with a gab (Q) of about 0.2 to 0.3 ax between the toner collecting row and the photoreceptor 1, and is driven to rotate in the direction of the arrow. A voltage of 500V is applied. 6 is a toner guide that guides the toner from above the toner collection roller 3 to the casing 2.
Lead to the bottom groove of 2. 7 is rotated by a screw so that a spiral blade sends toner into a toner reservoir.

Next, to explain the operation of the cleaning device, as mentioned above, when an untransferred toner image passes, the cleaning device does not operate, so the cleaning blade 2
It is held at a distance from the The cleaning blade 2 is brought into pressure contact with the photoreceptor 1 by the operation of the holding device directly when the residual toner after the transfer reaches a position opposite to the cleaning blade 2 of the cleaning 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 wire, and guided into the lower groove 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 conductive wire 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 an electric force based on an alternating current voltage, the invention is not limited to this, and a superimposed force 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 horizontal space between the cleaning blade and the photoreceptor, which improves the repeatability of the copying process. Toner accumulation at the cleaning point, which has an adverse effect, is removed, toner filming and paper powder contamination are prevented, and the life of the cleaning blade as a consumable item is extended 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 images 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 wire, 11... Cleaning device, 12... Yellow toner developing device, 15... Lining paper bag maker, 16... Transfer device, 17... Separator, 18...
・Fuser, 1...Shaft, 20...Holding device, 21・
...Holding member, 22...Casing, 23...Support body. Applicant's agent Fu Mitsuru Fujimoto l Figure 2

Claims (1)

[Claims] In a photoconductor cleaning device having a cleaning blade formed in a drum shape and pressed against the circumferential surface of a rotating photoconductor, a conductive wire is disposed forward in the direction of movement of the photoconductor near a contact point between the cleaning blade and the photoconductor. A photoreceptor cleaning device characterized by being provided with a power source that applies voltage to a conductive wire.