JPS6217776A - Transferring method for electronic copying machine - Google Patents

Abstract

PURPOSE:To obtain the high quality of a picture at high transferring efficiency by pressing a transfer paper with low pressure on the surface of an image by a transferring member having a charged dielectric layer and carrying separately with the transferring member while attracting the toner on the surface of the image to the transfer paper by electrostatic force. CONSTITUTION:Transfer paper 15 is carried into a transferring section 8 by a pair of paper feeding rollers 16 and 17. The transfer paper 15 is faced to the surface of image of a photosensitive body drum 1 by a paper guide 18. Then, the tip of the transfer paper 15 is brought into close contact with the surface of the image, and moved with the surface with the rotation of the drum 1, inserted into a transferring belt 9 and pressed on the surface of image of the photosensitive body with the low pressure. The transferring belt 9 is flexible member in which the surface in contact with the surface of image of the photosensitive body is made of a dielectric layer, and charged by a charger 14. Then, the toner on the charged surface is attracted onto the transfer paper by electrostatic force of the charged dielectric layer, and the transfer paper 15 is separated from the charged surface with the belt 9 and carried out in attracted state. Thus, the high picture quality can be obtained at high transferring efficiency.

Description

[Detailed description of the invention] The present invention relates to a transfer method in an electronic copying machine.

Various methods have been proposed as this type of transcription method. For example, corona transfer, in which transfer is performed under corona discharge, is commonly performed, but the photoreceptor deteriorates quickly, shortening its lifespan, and requires a separate conveyance means for the transfer paper. There are drawbacks. With metal bias roller transfer, electrical discharge occurs between the photoreceptor and the fine protrusions of the bias roller, damaging the photoreceptor, and the contact width between the photoreceptor and the bias roller is small, so transfer is not performed sufficiently. Furthermore, since the transfer paper quickly separates from the photoconductor after transfer, an electric force acts between the toner on the transfer paper and the charge remaining on the photoconductor, which may disturb the toner image on the transfer paper. be. Conductive rubber bias roller transfer also suffers from the drawback of electrical discharge between the photoreceptor and the fine protrusions of the bias roller.

The present invention aims to eliminate the above-mentioned drawbacks of the conventional transfer methods and obtain good image quality. The present invention will be described in detail below with reference to the accompanying drawings.

In FIG. 1, a charging section 2. Exposure section 3. Developing section 4. Transfer section 8. Static eliminator 5
．． Cleaning section 6. and a quenching lamp 7 are arranged. A transfer belt 9 that contacts the photoreceptor drum 1 at a low pressure according to the present invention in a transfer section 8 is connected to rollers 10 and 1.
1, 12, and 13. The transfer belt is made of, for example, a conductive endless belt base having a volume resistivity of 10 Ωl or less and a dielectric layer having a volume resistivity of 1d3 Ω1 or more, such as Teflon, polyethylene, polyester, or polyethylene terephthalate. The drive roller 12 and the photoreceptor drum 1 are rotationally driven by the same power source via a chain and sprocket, and in this case, the drive roller 12 drives the transfer belt 9 at the same running speed as the circumferential speed of the photoreceptor drum 1.

14 is a charging device for the transfer belt 9. The transfer paper 15 is conveyed to the transfer section 8 via a paper guide 18 by a pair of paper feed rollers 16 and 17. In this case, the transfer paper 15 is first directed toward the charged surface of the photoreceptor drum 1 by the paper guide 18. Next, the leading edge of the transfer paper 15 is as shown in FIG.
It comes into close contact with the charged surface of the photoreceptor, moves with the surface as the photoreceptor drum 1 rotates, enters between the photoreceptor drum surface and the transfer belt 9 that is in contact with it with low pressure, and is brought into contact with the charged surface of the photoreceptor. Contact is made with low pressure. Low pressure in this case is 10gr/aI to 5000gr/cti
range, especially 500gr10# to 20
A range of 00 gr/a# is advantageous. The transfer belt 9 is a flexible member whose surface in contact with the charged surface of the photoreceptor is made of a dielectric layer, and the dielectric layer is charged by a charging device 14 . Next, in the transfer section, as shown in FIG. 3, the electrostatic force of the charged dielectric layer attracts the toner on the charged surface onto the transfer paper, and in this tensioned state, the transfer paper 15 is separated from the charged surface together with the transfer belt 9. It will be transported out. In this case, the transfer paper is peeled off from the charged surface by the electrostatic force of the dielectric layer of the transfer belt 9. To facilitate this peeling action, an air jet nozzle 19 is installed as shown in the upper part of FIG. It is convenient to place it. The air ejected from the air ejection nozzle 19 is blown between the surface of the photoreceptor drum 1 and the leading edge of the transfer paper 15, thereby promoting separation between the two.

In the embodiment shown in FIG. 4, instead of a transfer belt.

A transfer roller 20 rotated in synchronization with the photoreceptor 1 is used, and the transfer roller 20 is in contact with the charged surface of the photoreceptor drum 1 under low pressure. For this reason.

The transfer roller 20 is made of a flexible material, such as chloroprene rubber or polyurethane rubber, which is subjected to conductive treatment and has a volume resistivity of 1.
It is convenient to be made of a material with a resistance of 0Ω or less. The surface of the transfer material 20 is made of the same dielectric layer as the transfer belt 9, and is charged by a charging device 14. An air jet nozzle 19 is arranged as an auxiliary means for peeling off the transfer paper 15 from the surface of the photoreceptor after transfer.

As mentioned above, in the present invention, since the transfer paper is brought into close contact with the charged surface in advance, there is no image shift, and since the transfer paper is brought into contact with the charged surface with low pressure by the transfer member, it is possible to prevent the toner from collapsing. No, in that case, static electricity is used for transfer, so if the charged potential of the dielectric layer is kept below a certain value, abnormal discharge will not occur between it and the photoreceptor.Furthermore, if the transfer paper is not in close contact with the transfer member, As the toner leaves the transfer section, the transfer paper and photoreceptor are gradually separated, and the electric field between the charge on the photoreceptor and the toner on the transfer paper changes relatively slowly, preventing the transferred image from being disturbed by the latent image. It is possible to obtain good image quality with high transfer efficiency.

[Brief explanation of drawings]

FIG. 1 is a schematic diagram of an electronic copying machine to which the present invention is applied. FIG. 2 is a partial diagram thereof, FIG. 3 is a functional explanatory diagram of the present invention, and FIG. 4 is a diagram showing another embodiment of the present invention. 1...Photosensitive drum 8...Transfer section 9...Transfer belt 9 15...Transfer paper 20...Transfer roller procedure amendment document August 8, 1986

Claims (1)

[Claims] The transfer paper is conveyed in advance in close contact with the charged surface, and the transfer paper is brought into contact with the charged surface under low pressure by a transfer member whose surface is made of a dielectric layer and this dielectric layer is charged, and then charged and the dielectric layer is charged. A transfer method for an electrophotographic copying machine, characterized in that toner on a charged surface is attracted onto a transfer paper by electrostatic force and then transported away from the charged surface together with a transfer member.