JPH01105980A - Image forming device having residual matter transfer mechanism - Google Patents

Abstract

PURPOSE:To curtail the cost of a cleaning device by electrifying a residual matter on a transfer intermediate body to the polarity opposite to the electrification charge of a photosensitive body. CONSTITUTION:A toner image of three colors is transferred onto a transfer intermediate body 24 is transferred by a transfer device 24b to a form fed from a feed paper part 3, and its form is peeled off by a peeling device 24c and fixed by a fixing part 4. On the other hand, even after the toner image is transferred to the form, the toner image remains behind on the intermediate body 24. Its residual toner and dust, etc., which is adhered to the intermediate body 24 are electrifed to negative by an electrifier 24d. When the intermediate body 24 is transferred the toner image and transfer the toner image to the form, the intermediate body 24 is electrified to positive by the transfer device 24a and 24b, but becomes a roughly neutralized state by the peeling device 24c and the electrifier 24d, and only the toner and the residual matter such as dust, etc., are electrified to negative. Also, in this case, a photosensitive body 2 is also electrified to positive by an electrifier 21, and the residual matter electrified to negative is transferred to the photosensitive body 2. The residual matter transferred to the photosensitive body 2 is removed by a cleaning device 25, and the photosensitive body 2 is destaticized by a destaticizing lamp 26.

Description

Detailed Description of the Invention (a) Industrial Application Field The present invention relates to an image forming apparatus that transfers a toner image on a photoreceptor to a transfer intermediate and then to paper, and the present invention relates to an image forming apparatus that transfers a toner image on a photoreceptor to a transfer intermediate and then to paper, The present invention relates to an image forming apparatus having a residue transfer mechanism for removing.

(bl) Conventional technology Some image forming apparatuses using electrophotography transfer the toner image on a photoreceptor to a transfer intermediate and then transfer it to paper. This method has the advantage that several 1-toner images can be superimposed on the body and then transferred to the paper, which eliminates the need to feed the paper many times when forming a full-color image or a composite image by trimming or masking.

(C) Problems to be Solved by the Invention In electrophotographic image forming apparatuses, even after the l/toner image has been transferred, some toner may remain on the surface of the photoreceptor or transfer intermediate. There may be dust etc.
Such residues such as toner and dust may degrade image quality as image stains during the next image formation. Therefore, in conventional image forming apparatuses, each of the photoreceptor and transfer intermediate is equipped with a cleaning device having a blade, fur brush, etc., to remove the residue on the surface of the photoreceptor and transfer intermediate at the end of the image forming process. Ta.

However, providing a cleaning device with a blade etc. for both the photoreceptor and the transfer intermediate requires a large number of parts (and therefore increases costs), and the cleaning device for the transfer intermediate does not have to be used to clean the toner image after it has been transferred to the paper. This requires a mechanism that comes into contact with the transfer intermediate after the transfer has been completed, and is separated from the transfer intermediate at other times, which has the drawback of complicating the device.

In addition, 1. Plates, fur brushes, etc. wear out due to friction with the photoreceptor and transfer intermediate, and if they are used many times, it becomes impossible to reliably remove residue, and they must be replaced at regular intervals. Therefore, it is desirable to use another method for cleaning if possible.

This invention transfers the residue of a transfer intermediate to a photoreceptor,
An object of the present invention is to provide an image forming apparatus having a residue transfer mechanism that can reduce the cost of a cleaning device and improve cleaning accuracy by removing residue on a photoreceptor.

Means for solving the fd1 problem An image forming apparatus having a residue transfer mechanism of the present invention transfers a toner image electrostatically formed on a charged photoreceptor to a transfer intermediate, and further transfers the toner image to a transfer intermediate. An image forming apparatus that forms an image by transferring it to a sheet of paper is characterized in that it includes a charger that charges the residue on the transfer intermediate to a polarity opposite to that of the photoreceptor.

(e) Function In the image forming apparatus having the residue transfer mechanism of the present invention, residues such as residual toner and dust on the transfer intermediate are charged by a charger to a polarity opposite to that of the photoreceptor.

Therefore, a Coulomb force is generated between the residue on the transfer intermediate and the photoreceptor, and the residue adheres to the photoreceptor. Therefore, the residue can be removed by simply providing a cleaning device on the photoreceptor without providing a cleaning device on the transfer intermediate.

(f) Embodiment FIG. 1 is a schematic diagram of a color copying machine which is an embodiment of an image forming apparatus having a residue transfer mechanism of the present invention.

A belt-shaped photoreceptor 2 is disposed approximately at the center of the main body 1 . Around the photoreceptor 2, a charger 21 for charging the photoreceptor, a blank lamp 22, developing devices 23a, 23b,
23c, transfer intermediate body 24, cleaning 25, and discharge lamp 26 are arranged in the above order. The charger 21 is a corotron discharger that fully charges the photoreceptor 2. The developing devices 23a, 23b, and 23c are each filled with toner of each color of yellow, magenta, and cyan, which is charged to negative. The cleaning device 25 includes a blade 25a that comes into contact with the photoreceptor 2.

The transfer intermediate body 24 is in contact with the photoreceptor 2, and there is a 1
A first transfer device 24a is provided, and a second transfer device 24b, a peeler 24c, and a charger 24d for residual material are arranged around the transfer intermediate 24 in the above order. The first transfer device 24a and the second transfer device 24b are corotron dischargers, (1) the separator 24c is an AC corotron discharger, and the charger 24d is a -corotron discharger.

A paper feed section 3 including a paper feed cassette 31 is disposed on the right side of the main body 1, and a fixing section 4 and a paper discharge section 5 are disposed on the left side. Further, a document table 6 is provided on the upper surface of the main body 1, and an optical system 7 is provided below the document table 6.

Next, the full color copying process (image forming process) will be explained.

In the full-color copying process, the process of forming a toner image on the photoreceptor is repeated three times, the toner image formed each time is transferred to the transfer intermediate 24, and the toner image formed each time is transferred to the transfer intermediate 24.
Color (yellow, magenta.

The three-color toner image is then transferred onto paper.

The photoreceptor 2 is fully and uniformly charged by the charger 2, and the document platen 6
The upper document is scanned by the optical system 6, and the photoreceptor 2 is exposed to the reflected light. At this time, the optical system 7 color-separates the reflected light from the original, and first exposes the photoreceptor 2 with the blue development reflected light to form a latent image having blue information. The developing device 2 is applied to the latent image.
3a, the unipolar yellow toner adheres to form a toner image, and this toner image is transferred to the 1st transfer device 24a.
The image is transferred to the transfer intermediate 24 by the following steps. After this, photoreceptor 2
Residues such as residual toner and dust on the photoconductor 2 are removed by a cleaning device 25, the photoreceptor 2 is neutralized by a static elimination lamp 26, and is further uniformly charged by a charger 21.

A latent image is then formed on the photoreceptor 2 by the reflected light of the green original, and magenta toner is attached by the developing device 23b to form a toner image. This toner image is transferred onto the transfer intermediate body 24 by the first transfer device 24a so as to be superimposed on the previous yellow toner image. Then, the photoconductor 2 is cleaned again by the cleaning device 25. Cleaning with the static elimination lamp 26.

The charge is removed and charged by the charger 21, and a latent image is formed by the red reflected light of the document. Cyan toner is attached to the latent image by the developer H23c to form a toner image, and the toner image is superimposed on the previous yellow and magenta toner images on the transfer intermediate 24 by the first transfer device 24a.

The three-color toner images of yellow, magenta, and cyan formed on the transfer intermediate body 24 as described above are transferred to the paper fed from the paper feed section 3 by the second transfer device 24b, and the paper is peeled off. It is peeled off by the container 24c, and the fixing unit 4
The image is fixed and the paper is ejected to the ejecting section 5.

On the other hand, even after the toner image is transferred onto the paper by the second transfer device 24b, toner remains on the transfer intermediate body 24. The residual toner and dust attached to the transfer intermediate body 24 are uniformly charged by the charger 24d. The transfer intermediate 24 is
When a toner image is transferred from the photoreceptor 2 and when a toner image on the transfer intermediate 24 is transferred to paper, the first transfer device 24a and the second transfer device 24b are sufficiently charged, but the stripping device 24c and this charging are sufficiently charged. The container 24d brings about a neutralized state, and only residual materials such as toner and dust are negatively charged.

At this time, the photoreceptor 2 is also fully charged by the charger 21, and the residue on the transfer intermediate 24, which is negatively charged as described above, is transferred to the photoreceptor 2 by Coulomb force. The residue transferred to the photoconductor 2 is removed by a cleaning device 25, and the photoconductor 2 is neutralized by a static elimination lamp 26.

As described above, the toner on the transfer intermediate body 24 is removed. The process of charging and transferring the residue on the transfer intermediate 24 may be performed once during one (one copy) copying process, but by performing it multiple times, the transfer intermediate 24 can be kept cleaner. can be in a state.

FIG. 2 shows a charger 24d and a charger 24d on the transfer intermediate 24 of this embodiment.
The number of copies is different when the cleaning device 25 is provided on the photoconductor 2, when the cleaning device is also provided on the conventional transfer intermediate, and when neither the cleaning device nor the charging device is provided on the transfer intermediate. FIG. 3 is a diagram illustrating the cleanliness of the transfer intermediate. Conventional products had a high degree of cleanliness in the initial stage, but as the number of times they were used increased, the degree of cleanliness decreased. This is thought to be because the blades etc. wear out with use. On the other hand, in this example, a stable cleanliness could be obtained regardless of the number of copies.

(g1) Effects of the Invention According to the image forming apparatus having the residue transfer mechanism of the present invention, a cleaning device for the transfer intermediate can be omitted, so costs can be reduced. Also, the cleaning accuracy of the transfer intermediate does not deteriorate (and a stable degree of cleanliness can be obtained).

[Brief explanation of the drawing]

Figure 1 is a schematic configuration diagram of a color copying machine that is an embodiment of the present invention, and Figure 2 shows the relationship between the number of copies and cleanliness in the same color copying machine and a color copying machine using a conventional cleaning device. It is a diagram. 21-Charger (for photoreceptor), 24-Transfer intermediate, 24d-Charger (for transfer intermediate).

Claims (1)

[Claims] (1) In an image forming apparatus that forms an image by transferring a toner image electrostatically formed on a charged photoreceptor to a transfer intermediate, and then transferring the toner image to paper, the residual amount on the transfer intermediate is An image forming apparatus having a residue transfer mechanism characterized by being provided with a charger that charges an object to a polarity opposite to that of a photoreceptor.