JPS62186238A - Transfer device - Google Patents

Abstract

PURPOSE:To remove the lack of an image at the leading edge of transfer paper by sending the transfer paper to the surface of a transfer paper holding means obtained by forming an insulating film n a conductive sheet and holding the transfer paper on the insulating film to superpose the transfer paper to a toner image and transfer the toner image to the transfer paper. CONSTITUTION:The transfer paper holding means 1 is constituted of the conductive sheet 2 consisting of a metallic film, conductive resin or conductive rubber and the insulating film 3 formed on the sheet 2 and consisting of polyethylene telephthalate, and the means 1 is formed like a seamless belt and its conductive sheet 2 side is earthed. The transfer paper is sent to the means 1 and charged with the same polarity as a toner carrier 7 by an electrifier 6. Since the corona current of the electrifier 6 is transmitted through the transfer paper 4, the insulating film 3 and the conductive sheet 2, the transfer paper 4 is electrified, strongly attracted and held to/on the film 3 and superposed to the toner image on the toner carrier 7 by a contact roll 8, so that the toner image is transferred to the surface of the transfer paper 4 then the transfer paper 4 is destaticized.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a transfer device suitable for electrophotographic apparatuses, particularly electrophotographic apparatuses such as color copying machines.

(Prior art) The transfer device of a conventional color copying machine was
The transfer device disclosed in Japanese Patent No. 64 will be explained as an example. This transfer device consists of a thin wire member that holds the transfer paper and a drum made of an insulating film.The transfer paper is gripped by the leading edge of the transfer paper and flanged with a claw, and the transfer paper is wrapped around the drum and pressed against the toner image carrier to transfer the paper. The toner image is transferred to the transfer paper using a corona charger inside the drum that holds the paper.

(Problems to be Solved by the Invention) In the conventional transfer device, the tip 5 to 10 of the transfer paper
There was a problem that the tone image was missing.

In addition, since the means for holding the transfer paper is a drum with a circumference equal to the length of the transfer paper, a large drum is required, and the thin insulating film is formed into a drum shape with high dimensional accuracy while maintaining its strength. The problem was that it was difficult to

(Means for Solving the Problems) In order to solve the above-mentioned problems, the present invention provides a method in which a transfer paper is fed by a paper feeding means onto the surface of a transfer paper holding means in which an insulating film is formed on a conductive sheet. A small and simple transfer device that eliminates image chipping at the leading edge of the transfer paper by holding the transfer paper on the insulating film and overlapping the toner image on the toner image carrier and transferring the toner image to the transfer paper. It provides:

(Function) According to the above structure, since the transfer paper holding means has an insulating film formed on the conductive sheet, it is flexible and can be bent freely. can be downsized. In addition, 4. When stacking the transfer paper on the toner image carrier, it is possible to press the transfer paper with a flexible transfer paper holding means, so that the dimensional accuracy of the transfer paper holding means is not required. Furthermore, since the adsorption force between the charged transfer paper and the insulating film is strong, there is no need to particularly flang the leading edge of the transfer paper, and image chipping at the leading edge of the transfer paper is eliminated.

(Example) A transfer device of the present invention will be described with reference to FIGS. 1 and 2. FIG. 1 is a schematic sectional view of an embodiment of a transfer device of the present invention, and FIG. 2 is a sectional view of a transfer paper holding means of the transfer device.

As shown in FIG. 2, the transfer paper holding means 1 includes a conductive sheet 2 made of a metal film, conductive resin, or conductive rubber with a specific resistance value of 10 Ω·α or less, and a conductive sheet 2 on the conductive sheet 2. The insulating film 3 is made of polyethylene terephthalate, fluorinated resin, or the like and has a specific resistance of 10 6 Ω·α or more. Further, the transfer paper holding means 1 is formed seamlessly into a belt shape, and the conductive sheet 2 side is grounded. The transfer paper 4 is sent to the transfer paper holding means 1 in the direction of the arrow by the paper feeding means 5, and is charged to the same polarity as the toner image carrier 7 by the charger 6. Since the corona current of the charger 6 passes through the transfer paper 4, the insulating film 3, and the conductive sheet 2, the transfer paper 4 is charged and at the same time is strongly attracted and held by the insulating film 3 and moves in the direction of the arrow. Sent. Since the circumferential speed of the toner image carrier 7 and the conveyance speed of the transfer paper holding means 1 are the same, the conveyed transfer paper 4 is superimposed on the toner image on the toner image carrier 7 by the pressure roll 8. The toner image is transferred onto the transfer paper 4.

Next, after applying an alternating current voltage to the static eliminator 9 to eliminate static electricity from the transfer paper 4, the transfer paper 4 is separated from the transfer paper holding means 1 and conveyed to the fixing means 10. However, in the case of a color copier, 3
In order to transfer color or four-color toner images in a superimposed manner, the transfer paper 4 held in the transfer paper holding means 1 is not statically removed by just one transfer, but the transfer paper holding means 1 is rotated three or four times. After the transfer of each color is superimposed, the transfer paper 4 is neutralized by a static eliminator 9 and conveyed from the transfer paper holding means 1 to the fixing means 10.

According to the present invention, since the adsorption between the transfer paper 4 and the insulating film 3 is strong, the transfer paper 4 is transported without being separated from the insulating film 3 even if the curvature of the transfer paper holding means 1 is small. Therefore, by forming the transfer paper holding means 1 in the shape of a windshield, the entire transfer device can be made thinner. Further, since the transfer paper holding means 1 is flexible, the transfer paper 4 can be pressed against the toner image carrier 7 by the pressure roll 8, and there is a gap between the transfer paper 4, the toner image carrier 7, and the insulating film 3. Gaps are less likely to occur, and even if the dimensional accuracy of the transfer paper holding means 1 is not so good, transfer can be performed efficiently.

(Effects of the Invention) According to the present invention, a transfer paper is fed onto the surface of a transfer paper holding means in which an insulating film is formed on a conductive sheet, and the transfer paper is charged and held on the insulating film. Since the toner image is transferred to the transfer paper overlapping the toner image on the toner image carrier, there is no need to particularly flang the leading edge of the transfer paper, and there is no loss of the image on the leading edge of the transfer paper. In addition, since the transfer paper holding means is flexible and has good ability to hold the transfer paper, the transfer paper holding means can be flattened and the entire transfer device can be downsized, and the transfer paper can be pressed against the toner image carrier and brought into close contact with the toner image carrier. This has the effect of providing a simple transfer device that does not require much dimensional accuracy of the transfer paper holding means.

[Brief explanation of drawings]

FIG. 1 is a schematic sectional view of an embodiment of a transfer device of the present invention, and FIG. 2 is a sectional view of a transfer paper holding means of the transfer device. DESCRIPTION OF SYMBOLS 1... Transfer paper holding means, 2... Conductive sheet, 3...
... Insulating film, 4... Transfer paper, 5... Paper feeding means, 6... Charger, 7... Toner image carrier, 8...
- Pressure roll, 9... static eliminator, 10... fixing means. Figure 1 1 Roll 5 paper style poem 4・motion 1 wind 8・°° 490-i 9゛cypress (I) 1o...fL bite rk Figure 2 2... Conductive sheet 3゛ Kura - ball play 14 rem

Claims (3)

[Claims] (1) A transfer paper is sent by a paper feeding means to the surface of a transfer paper holding means in which an insulating film is formed on a conductive sheet, and the transfer paper is charged and held on the insulating film,
A transfer device characterized in that the toner image is transferred to the transfer paper by overlapping the toner image on the toner image carrier. (2) The transfer device according to claim (1), wherein the transfer paper holding means is formed in the shape of a belt. (3) Rotate the transfer paper holding means while holding the transfer paper multiple times to transfer a plurality of toner images in an overlapping manner onto the transfer paper on the transfer paper holding means, and after completing the overlapping transfer, the transfer paper 2. The transfer apparatus according to claim 1, wherein the transfer paper is electrically discharged immediately before being separated from the transfer paper holding means.