JPS61120180A - Cleaning method of photosensitive body in electrophotography - Google Patents

Abstract

PURPOSE:To obtain a sharp image even from a white ground original by providing a darkl part to a front white plate on an original platen, forming a toner sticking potential part on the surface of a photosensitive body, and cleaning sticking toner and paper powder on the surface of the photosensitive body. CONSTITUTION:The dark part 4 is provided on the reverse surface of the front end white plate 3 which positions the front end position of an original on the original platen 2 to the overall length in the lengthwise direction, and the toner sticking potential part is formed at the part corersponding to the dark part 4 on the surface of the photosensitive body. Therefore, even when an original has a large white ground and the amount of toner sticking on the surface of the photosensitive body is small, paper powder sticking the surface of the photosensitive body during transfer operation is cleaned completely by mixing with toner sticking on the toner sticking potential part, so image trailing due to the paper powder is prevented and an invariably sharp image is formed.

Description

[Detailed Description of the Invention] (Industrial Application Field) The present invention uniformly charges the surface of a υ photoconductor by a charging means,
An electrostatic latent image is formed on the surface of the photoreceptor by the image exposure means, toner is attached to the electrostatic latent image by the developing means to form a toner and visible image, and the toner visible image is transferred onto paper by the transfer means. An electrophotographic method in which residual toner remaining on the surface of the photoreceptor after transfer and paper dust attached to the surface of the photoreceptor during transfer are cleaned using a cleaning means, especially when copying a large number of originals with many white backgrounds. The present invention relates to a photoconductor cleaning method that completely removes paper dust adhering to the photoconductor and prevents image defects due to paper dust.

(Prior Art) A conventional electrophotographic method will be explained by taking an electrophotographic copying machine as shown in @4 factors as an example.A photoreceptor 1001 rotates in the direction of the arrow! : The charger 101 uniformly charges the document 102 , and then the exposure lamp 103 illuminates the document 102 placed on the document table 102 moving in the direction of the arrow, and the document is exposed onto the photoreceptor 100 via the short focus lens array 104 . The image is formed to form an electrostatic latent image, and then toner is attached to the electrostatic latent image by the developing device 105 to form a toner visible image.On the other hand, the guide 108 and The copy paper 1)0 is conveyed through the copy paper 109, and a toner image is transferred onto the copy paper 1)0 by a charger 1)1. , furthermore, the photoreceptor 10
1) Cleaning the residual toner remaining on the 00 paper and the copy paper adhering to the photoreceptor surface during transfer with cleaning grade 1
) 2 to clean the surface of the photoreceptor 100. At this time, the paper dust mixes with the residual toner to form a part that is easy to clean and is removed from the surface of the photoreceptor 100.

(Problems to be Solved by the Invention) However, in the conventional method described above, when an original with a lot of white background is taken, the amount of toner that adheres to the surface of the photoreceptor as a toner image is small, and during transfer. Paper dust adhering to the photoreceptor surface is not completely removed and remains on the photoreceptor surface. Therefore, when a large number of originals 102 with many white backgrounds are repeatedly copied, there is a problem in that paper dust accumulates and image deletion occurs in the copied images. That is, the copy paper 1)0 usually has paper dust generated during paper cutting or paper dust generated during paper conveyance adhering to it. It has been well known that as a result of paper fibers breaking on the cant surface of copy paper 1)0, the filler in the paper is released from the fibers. Kaolin, clay, talc, etc. are usually used as such fillers, and talc has no adverse effect on the quality of copied images, and its main component is a hydrous silicate mineral of magnesium. Such a filler is detached from the paper powder and adheres to the surface of the photoreceptor 100;
It is difficult to completely wipe away the surface of the photoreceptor 100 during cleaning, and a conductive layer is formed on the surface of the photoreceptor 100 due to the filler deposits remaining on the surface of the photoreceptor 100. This makes it difficult to charge, which causes image blurring.

The present invention has been made to solve the problems of the prior art, and its purpose is to eliminate paper dust that adheres to the surface of the photoreceptor even when old documents with many white backgrounds are printed. Provide a photoreceptor cleaning method for electrophotography that can be completely removed to prevent image fading due to paper dust, and always
The purpose is to obtain clear images.

(Means for Solving the Problems) In order to achieve the above object, the present invention provides an electrostatic latent image corresponding to an image to be printed on the surface of a photoreceptor, and a rotational pattern of the photoreceptor. Upstream and downstream potential contact metal fittings,
The toner is made to adhere to the toner adhesion potential portion by a developing means, and is cleaned by a cleaning means along with residual toner remaining on the surface of the photoreceptor and paper dust adhering to the surface of the photoreceptor during transfer.

(Example) The present invention will be explained below based on illustrated embodiments.

FIG. 1 schematically shows an electrophotographic apparatus 1 used in a photoreceptor IJ + coating method of an electrophotographic method according to an embodiment of the present invention. In the electrophotographic apparatus of this embodiment, the surface of the photoreceptor is uniformly charged by the charging means, and the S document is scanned by moving the document table 2 to form an electrostatic latent image on the surface of the photoreceptor. , toner is attached to the electrostatic latent image by a developing means to form a toner image gI, and the toner image formed on the surface of the photoconductor is transferred to copy paper by a transfer means, and the toner remains on the surface of the photoreceptor after the transfer. The remaining toner and the paper dust of the copying paper adhering to the surface of the photoreceptor during transfer are removed by a cleaning means in the same manner as in the conventional example.

In this embodiment, as shown in FIG. 1, a black dark portion 4 is provided on the back side of a leading edge white plate 3 for positioning the leading edge position of the document on the document table 2. As shown in FIG. The dark portion 4 extends over the entire length in the longitudinal direction of the white tip plate 3.
The length of is set according to the document width of the maximum copy size of the document.

Therefore, even in the case of a small-sized original, the dark portion 4 will exist corresponding to the width of the original.

In the copying apparatus configured as described above, the copying operation of the original is performed by first exposing the image of the dark portion 4 to the image exposure means before an electrostatic latent image of the original is formed on the photoreceptor as the original table moves. However, since the dark area 4 is black, the area corresponding to the dark lB4 on the surface of the photoreceptor becomes an unexposed area, that is, a toner adhesion potential area, and the surface potential of the surface becomes high. ing. In other words, the toner adhesion potential area is
It is formed on the upstream side of the electrostatic latent image of the original in the rotational direction of the photoreceptor. Next, the original and the finishing section 4 are processed by the developing means.
A toner image is formed. Next, the toner image of the document is transferred to the copy paper that is conveyed to the photoreceptor.
The image on the border 4 is not transferred because it is outside the frame of the copy paper. Therefore, the toner image formed corresponding to the dark area 4 is cleaned as it is in the toner L cleaning process.

゛ On the other hand, after copying an original with a lot of white background and transferring the image to copy paper, there is a small amount of residual toner in the toner image of the original image on the narrow surface of the photoconductor, and there is also a small amount of toner remaining in the toner image of the original image, and there is also a small amount of toner remaining in the toner image of the original image, and there is also a small amount of toner remaining on the narrow surface of the photoreceptor after copying an original with a lot of white background and transferring the image to copy paper. In cases where paper dust containing talc etc. adheres to the surface, it is difficult to remove the paper dust during the cleaning process. However, the original image on the surface of the photoreceptor! Since the toner l1iIIIi image of the upper fillK dark area 4 in the rotational direction of the photoconductor remains with respect to the light area, that is, the contact area of the copy paper, the SC light body Il! The paper dust on the surface is mixed with the toner of the toner image in the dark area 4 and is completely removed. Therefore, no talc remains on the surface of the photoreceptor, and no talc layer is formed even if a large number of originals with many blank areas are copied.

The cleaning effect of the present invention is particularly great in a copying apparatus having a cleaner configured to scrape off residual toner on the surface of the photoreceptor using a cleaning blade as a cleaning means. The reason for this is that toner accumulates in the contact area between the cleaning blade and the surface of the photoreceptor, and the paper dust on the photoreceptor is cleaned with a sufficient amount of toner.

In this embodiment, a dark area 4 is provided on the back side of the leading white plate 3 on the document table 2 to form a toner-applied WE portion on the surface of the photoreceptor, but as shown in FIG. A dark portion 4 may be provided on the back surface of the document pressure bonding plate 5, which may be axially laminated, and a layer potential portion with toner may be provided on the surface of the photoreceptor. Note that 6 in the figure is a manuscript. In this case, a toner-applied portion at Xf1M is formed on the downstream side in the rotational direction of the photoreceptor with respect to the area of the electrostatic M image of the document on the surface of the photoreceptor.

Further, instead of the original pressure bonding plate 5, a similar dark portion 4 may be provided on thick paper and the original may be pressed from above.

In this embodiment, the image of the dark area 4 is projected onto the photoreceptor by an optical system, but the area between the latent images corresponding to the image to be transferred to the paper is illuminated to generate a potential. Non-image area exposure means 1) 3(
(The charging device 101 is provided in the section between the developing devices 105)
When using LEDs (light emitting diodes) arranged in an array, the toner can be transferred onto the photoreceptor by turning off the LEDs at a predetermined position outside the frame of the document without providing a dark area. An adhesion potential portion may be provided to allow the toner to adhere. In this case, it is possible to save toner consumption by providing a changeover switch so that the toner adhesion potential area is formed only when copying originals with many white backgrounds. The present invention can also be applied to an apparatus that scans an original by moving a mirror, a lens, etc.

Furthermore, the image 'f to be printed is transmitted to a laser beam modulated by the electrical information signal Ig, or to an LE driven by the signal.
It can also be applied to devices formed using D arrays and liquid crystal shutter arrays. In such an apparatus, if a so-called reversal development method is adopted in which a corpse area to which toner is to be attached is exposed to light, and a toner having a polarity opposite to that of the dark area potential is attached to the exposed area, the toner is not attached. The potential portion is formed by irradiating light onto a predetermined portion of the photoreceptor at a predetermined time using a laser beam, an LED array, a liquid crystal shutter, or the like. Of course, other light sources may also be provided for this purpose.

(Effects of the Invention) The photoreceptor cleaning method in the electrophotographic method according to the present invention has the above-described configuration and operation, and even when the amount of toner adhering to the photoreceptor surface is small in an original with a large white background, the The paper powder that adheres to the surface of the photoreceptor is mixed with toner that adheres to the toner adhesion potential area that is formed on at least one of the upstream and downstream sides of the photoreceptor's rotational direction relative to the electrostatic potential on the surface of the photoreceptor. Since the surface of the photoreceptor is completely cleaned by the stitching, image deletion does not occur even when printing a large number of documents with many white backgrounds, and the effect is that a clear image can always be obtained.

[Brief explanation of drawings]

Fig. 1 is a schematic perspective view of a copying apparatus used in an embodiment of the method of the present invention, Fig. 2 is a schematic perspective view of the back side of the document table of the apparatus shown in Fig. 1, and Fig. 3 is a dark part of the original pressed. The first plate provided on the board
FIG. 4 is a schematic perspective view of the vicinity of the document table of the apparatus shown in the figure, and FIG. 4 is a schematic configuration diagram showing an example of a conventional copying apparatus. Explanation of symbols

Claims (1)

[Claims] (1) The surface of the photoreceptor is uniformly charged by the charging means, the document image is exposed on the surface of the photoreceptor by the image exposure means to form an electrostatic latent image, and the electrostatic latent image is formed by the developing means. A toner image is formed by attaching toner to the surface of the photoreceptor, the toner image is transferred to paper by a transfer means, and residual toner remaining on the surface of the photoreceptor after transfer and paper dust adhering to the surface of the photoreceptor during transfer are cleaned. In the electrophotographic method of cleaning the photoreceptor surface, the electrostatic latent image on the surface of the photoreceptor is located on at least one of an upstream side and a downstream side in the rotational direction of the photoreceptor, and in the conveyance direction of the paper of the original document. A toner adhesion potential portion extending in the right angle direction and corresponding to at least the document width is provided, toner is adhered to the toner adhesion potential portion by a developing means, and residual toner remaining on the surface of the photoreceptor and transfer is removed by the cleaning means. A method for cleaning a photoreceptor in an electrophotographic method, characterized in that the photoreceptor is sometimes cleaned together with paper dust adhering to the surface of the photoreceptor.