JPS63194282A - Image forming device - Google Patents

Abstract

PURPOSE:To accurately and efficiently transfer the image on the surface of a photosensitive body to a form by roughening the rear face and smoothing the front face of an endless transfer belt. CONSTITUTION:The front face of a transfer belt 1 which is brought into contact with a photosensitive drum 4 is smoothed, and the rear face of this belt 1 which is brought into contact with driving rolls 2 and 3 is roughened. When the toner image on the surface of the photosensitive drum is transferred to the transfer belt 1 or the toner image on the transfer belt 1 is transferred to the transfer form, the toner image is efficiently transferred because the front face of the transfer belt 1 is smooth, and the toner image after transfer is not varied. Further, the contact resistance to driving rolls is increased and slip or the like does not occur at the time of transfer because the rear face of the transfer belt is rough. Thus, the image is efficiently transferred, and the image quality after transfer is improved because slip does not occur at the time of transfer.

Description

Detailed Description of the Invention (AL Industrial Field of Application) This invention relates to image formation using an endless belt as a transfer member that contacts the surface of a rotating photoreceptor and transfers an image on the surface of the photoreceptor to the contact portion. Regarding equipment.

('b) Prior Art In general, in electrophotographic copying machines, when an electrostatic latent image of an original image is formed on the surface of a photoreceptor such as a photoreceptor drum during the exposure step of the copying process, the electrostatic latent image is formed during the development step. The image is developed with toner and visualized. Furthermore, after the toner image is transferred to paper in a transfer process, it is heated and pressurized by a fixing roller or the like to be fixed.

By the way, in devices such as color copying machines that make copies of different colors on a single sheet of paper, toner images of different colors formed on a photoreceptor are sequentially transferred onto a transfer member in order to make copies of different colors. Thereafter, the completed color toner image is transferred onto transfer paper.

FIG. 3 is a schematic configuration diagram showing a photosensitive drum, a transfer sheet, and their peripheral parts of a copying machine which is an example of the above color copying machine.

In the color copying machine shown in FIG. 3, a belt-shaped transfer sheet 24 is passed over a rack by drive rollers 22 and 23 to the left side of a photoreceptor drum 21 that rotates clockwise.
The transfer sheet 24 is rotated counterclockwise by driving one of the drive rollers 22 and 23, and the right side surface of the transfer sheet 24 is in contact with the surface of the photoreceptor drum 21. Further, a transfer charger 25 is arranged inside the belt at the contact portion.

In the above color copying machine, when the photoreceptor drum 21 rotates clockwise during the copying process, the transfer sheet 24 is rotationally driven in the same direction as the photoreceptor drum 21 by the driving rollers 22 and 23, and the photoreceptor The toner image on the surface of the photosensitive drum 21 is transferred onto the surface of the transfer sheet 24 by the transfer charger 25 at the contact portion with the surface of the drum 21 . In the case of color copying, this transfer is repeated several times until the toner images of each color (magenta, yellow, cyan, blank) are superimposed, and then the color toner images formed on the transfer sheet 24 are Transferred to external transfer paper. A sensor 26 shown in the figure is used for positioning the toner image on the photosensitive drum 21 to be superimposed on the transfer sheet.

In this manner, the color copying machine described above enables color copying by once forming a color toner image by overlapping toner images of different colors on a transfer sheet, and then transferring this toner image onto a transfer sheet.

(C) Problems to be Solved by the Invention However, the image forming apparatus described above requires smoothness of the surface of the photoreceptor. If the surface of the transfer belt onto which the image is transferred has poor smoothness, the transfer will not be carried out sufficiently, resulting in a problem that the image will be uneven. On the other hand, the back surface of the transfer belt must not be smooth. If this back surface is smooth, it may slip between it and the drive roller, and the toner image on the surface of the photoreceptor will not overlap the toner image previously transferred to the transfer belt, making it impossible to obtain a good image.

In view of the above, an object of the present invention is to improve the smoothness of the surface of the transfer belt and to roughen the contact surface with the drive roller on the back surface of the transfer belt, so that the image on the surface of the photoreceptor is accurately and efficiently transferred to paper. An object of the present invention is to provide an image forming apparatus that has the following features.

(Means for solving problem d1) In the image forming apparatus of the present invention, the transfer body is constituted by an endless transfer belt, and the back surface of the endless transfer heald is roughened.
It is characterized by a smooth surface.

(21 Effects of the Invention) In the image forming apparatus according to the present invention, when the image formed on the surface of the photoconductor comes into contact with the transfer body and is transferred to the surface of the transfer body, since the surface of the endless belt-shaped transfer body is smooth, The image on the photoreceptor is efficiently transferred to the surface of the photoreceptor.Furthermore, since the back surface of the transfer body is rough, friction with a driving body such as a drive roller is large, and slippage does not occur between the driving body and the transfer body. As a result, the image formed on the photoreceptor is accurately and efficiently transferred to the transfer paper.

(f) Embodiment FIG. 1 is a schematic diagram of the photosensitive drum, transfer belt, and peripheral parts of a color copying machine according to an embodiment of the present invention.

The configuration of the color copying machine shown in FIG. 1 differs from the conventional color copying machine shown in FIG. 2 in the configuration of the transfer belt. The transfer bell) 1 of this embodiment has a smooth surface that contacts the photoreceptor drum 4, and a drive roller 2, 3.
The back surface that comes into contact with the surface is roughened. FIG. 2 is a partial sectional view of the transfer belt 1. As shown in FIG. In the figure, A shows the front side, and B shows the back side. The rest of the structure is the same as the conventional one. When the photosensitive drum is rotated clockwise during the copying process and a toner image is formed on its surface, the drive rollers 2 and 3 are driven clockwise. Transfer belt 1
A toner image is transferred onto the transfer belt by a transfer charger 5, and the position of the superimposed toner images is controlled by the output of a sensor 6 that detects the movement of the transfer belt 1.

In the above color copying machine, the surface of the transfer belt 1 is smooth when the toner image on the surface of the photosensitive drum 4 is transferred to the transfer belt 1 or when the toner image on the transfer belt l is transferred to the transfer paper. The toner image is transferred efficiently, and the toner image after transfer is uneven.Also, because the back surface of the transfer belt is roughened, the contact resistance with the drive roller becomes large.
No slipping occurs during transfer. As described above, the color copying machine of this embodiment has the advantage that the image quality after transfer is good because the transfer can be performed efficiently and slips do not occur during transfer.

Although a color copying machine is shown in this embodiment, the present invention is of course applicable to ordinary copying machines and the like.

(g1 Effects of the Invention As described above, in the image forming apparatus of the present invention, the image on the surface of the photoconductor is transferred to the surface of the transfer belt by improving the smoothness of the surface of the transfer belt and forming the back surface to be rough. Since the toner image is efficiently transferred onto the transfer paper, the smoothness of the surface of the transfer belt is poor, causing white spots on the image and unevenness of the image. Since the contact resistance is increased and slip between the drive roller and the transfer heald does not occur, there is an effect that a good image can be obtained without occurrence of image deletion due to slip.

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram showing the main parts of an image forming apparatus according to an embodiment of the present invention, and FIG. 2 is a partial sectional view of a transfer belt. FIG. 3 is a schematic configuration diagram showing the main parts of a conventional image forming apparatus. 1-transfer heald (transfer body), 2-driving roller, 3-driving roller, 4-photosensitive drum.

Claims (1)

[Claims] (1) The transfer body is composed of an endless transfer belt, and
An image forming apparatus characterized in that the back side of the endless transfer belt is roughened and the front side is smoothed.