JPS6049310B2 - pressure fixing device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides a pressure fixing device, in particular a pressure roll that pressure fixes a toner image developed or transferred onto a recording paper onto the recording paper, so as to be electrically insulated from ground. This invention relates to a pressure fixing device.

Generally, in an electrophotographic apparatus, a toner image formed by transferring toner developed on a photoreceptor to recording paper by electrostatic transfer, or a toner image formed by directly developing toner on electrostatic recording paper, In order to form a fixed head image on the above-mentioned ordinary recording paper or electrostatic recording paper, two
This is carried out by passing ordinary recording paper or electrostatic recording paper on which the toner image has been formed between the pressure rolls of the book, and using a pressure fixing device that fixes the toner image on the recording paper under pressure.

Conventionally, the pressure roll in the pressure fixing device is electrically integrated with the main unit in which the pressure fixing device is installed and is grounded. Therefore, the electrical charge of the toner on the recording paper is grounded via the pressure roll, and as a result, the toner is transferred onto the pressure roll, resulting in poor image resolution during the pressure fixing, and Development occurs in which the outline becomes blurred.
The present invention aims to solve the above problems,
It is an object of the present invention to provide a pressure fixing device in which a pressure roll of the pressure fixing device is insulated from ground, preventing transfer and diffusion of toner fixed to recording paper, and obtaining a clear image with good resolution. The purpose is

This will be explained below with reference to the drawings. FIG. 1 is a perspective view of one embodiment of the present invention for explaining the present invention, and FIG. 2 is a side view taken in the direction of the arrow shown in FIG. In the figure, 1 is a first pressure roll, 2 is a second pressure roll,
3 and 4 are compression coil springs, 5 and 6 are housings, 7 is a base, 8 is a sprocket and J-wheel, and 9 and 10 are electrical insulation parts, respectively.

As shown in FIG. 1, the pressure fixing device has a pair of steel rolls, ie, first and second pressure rolls 1 and 2, whose axes cross each other, and compressed coil springs 3, 4.
The housing 5 is pressurized by the housing 5 and fixed to the base 7.
, 6.

In the embodiment shown in FIG. 1, a sprocket wheel 8 fixed to the second pressure roll 2 is driven by a drive device (not shown), and the first and second pressure rolls 1 and 2 are driven by a drive device (not shown). They are designed to rotate in tandem. Therefore, the first and second pressure rolls 1 and 2
If the main unit in which the pressure fixing device is installed via the housings 5, 6 and the base 7, or the transmission mechanism that transmits the power of the drive device (not shown) to the sprocket wheel 8 is a conductor, Above sprocket
It is electrically connected to the main unit and grounded via the foil 8 and a transmission mechanism (not shown). An embodiment of the present invention in which the first and second pressure rolls 1 and 2 are electrically insulated from earth is shown in FIGS. 1 and 2.
As shown in the figure. In FIGS. 1 and 2, the housings 5 and 6 are electrically insulating parts 9 formed of electrical insulators.
, 10 to the base 7, and the sprocket foil 8 is made of an electrical insulator, thereby insulating the first and second pressure rolls from ground. . As described above, the first and second pressure rolls 1 and 2 are insulated from the ground, so that the recording paper on which the toner image is formed passes between the pressure rolls 1 and 2. During pressure and force fixing, the electric charge on the toner is not grounded, so the toner on the recording paper does not transfer or diffuse onto the roll, and the state of the developed or transferred image is maintained. Pressure fixation is used to maintain clear images with good resolution. An image is obtained. In the embodiment shown in FIGS. 1 and 2, the electrical insulation is achieved by interposing the electrical insulation parts 9, 10 between the housings 5, 6 and the base 7. However, an electrically insulating section may be provided between the base 7 and the present device, or the transmission mechanism (not shown) for driving the sprocket wheel 8 may be made of a non-conductive material. Alternatively, the first and second pressure rolls 1 and 2 may be supported by the housings 5 and 6, respectively, via electrical insulators, but in this case, the first and second pressure rolls It is necessary to fully consider the pressing force exerted by the compression coil springs 3 and 4 of the rolls 1 and 2, and select the electrical insulator that has a mechanical strength capable of withstanding the pressing force. As explained above, according to the present invention, by electrically insulating the pressure roll in the pressure fixing device from the ground, the toner to be fixed on the recording paper can be transferred to the pressure roll, and the toner can be transferred onto the recording paper. It is possible to provide a pressure fixing device that prevents diffusion in the image and provides clear images with good resolution.

[Brief explanation of drawings]

FIG. 1 is a perspective view of one embodiment of the present invention for explaining the present invention, and FIG. 2 is a side view taken in the direction of the arrow shown in FIG. In the figure, 1 is a first pressure roll, 2 is a second pressure roll,
3 and 4 are compression coil springs, 5 and 6 are housings, 7 is a base, 8 is a sprocket foil, and 9 and 10 are electrical insulation parts, respectively.

Claims (1)

[Claims] 1. It has a pair of pressure rolls that rotate in contact with each other, and a support member that supports the pressure rolls, and a recording paper on which a toner image has been developed or transferred is passed between the pressure rolls, and the toner image is transferred. In a pressure fixing device that fixes a toner image formed on a recording paper under pressure, the support member is provided with an electrical insulator to electrically insulate the pressure roll from ground. Features a pressure fixing device.