JPH0310950B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an improvement in a heat roller fixing device used in an electronic copying machine or the like, which fixes thermoplastic toner on a support by contact heating the thermoplastic toner on the support.

For example, the image forming process using an electronic copying machine is
An electrostatic latent image corresponding to the original image is formed on a charge holding body using an insulating photoconductor as a photoreceptor by corona charging and light irradiation, and this image is transferred to an electrostatic latent image consisting mainly of thermoplastic colored fine powder. A visible image is formed by developing with a developer.

The visible image, that is, the toner image on the charge carrier is transferred onto a support such as transfer paper by electrical means such as corona discharge or physical means such as pressing.

The toner image transferred onto the transfer paper by the above method is fixed onto the transfer paper by a conventional heating means, and the image forming process is completed. Here, there is a heat roller fixing device as a fixing device that fixes a toner image on a transfer paper using a heating means.

A heated roller fixing device applies pressure between two rollers, one of which is heated, and performs fixing by inserting and passing a support carrying an unfixed toner image between these rollers.This type of fixing device The fixing roller (hereinafter referred to as the first roller) on the side that comes into contact with the toner image on the support is made of a metal with good heat conductivity, such as brass or aluminum, and has a tubular shape, and the surface is coated with a heat-resistant release material such as tetrafluorocarbon.・It is coated with ethylene and has a heat source inside it. The other pressure roller (hereinafter referred to as the second roller)
It is known to use elastic rubber such as silicone rubber.

In such a heat roller fixing device, a support carrying thermoplastic toner is passed between a first roller at a set temperature and a second roller that is in pressure contact with each other, and the toner is melted by the first roller and then transferred to the support. The toner undergoes a so-called fixing process, but the toner
It is difficult to completely adhere to the support and keep the first roller completely clean, and some toner residue and support stains will adhere to the first roller surface. If the surface of the first roller gets dirty, the quality of the image after fixing will deteriorate, so a cleaning blade should be pressed against the first roller,
Toner residue and dirt on the support are removed from the first roller by bringing a rotating cleaning roller into contact with the first roller.

When toner residues and the like adhering to the circumferential surface of the first roller are removed by the brush-like cleaning roller, the removed toner residues gradually adhere to the cleaning roller. As the cleaning roller becomes dirty, the cleaning effect of the cleaning roller gradually decreases. In order to prevent this, the brush-like fibers of the cleaning roller have been treated with a release agent. This treatment improved the durability of the cleaning roller. However, even under such conditions, when the release agent is consumed, the cleaning roller eventually becomes dirty with toner, and it is necessary to replace it at every maintenance.

The present invention aims to eliminate the above-mentioned drawbacks and provide a heat roller fixing device that does not require parts replacement every time maintenance is performed.
A cleaning roller around which heat-resistant fibers are implanted like a brush is brought into contact between the heat fixing roller and a release agent-impregnated member impregnated with a release agent;
The cleaning roller and the heat fixing roller are arranged to rotate with a speed difference at a contact point, and the cleaning roller removes the toner on the heat fixation roller and separates it from the release agent impregnated member. This is accomplished by a hot roller fixing device configured to supply molding agent to the heat fixing roller.

Hereinafter, the present invention will be explained in detail using the drawings.

FIG. 1 is a sectional view showing an outline of a heat roller fixing device according to the present invention. In the figure, 1 is a cylindrical first roller, and there is a heat source such as an infrared lamp inside.
A is provided and rotates clockwise during fixing. Reference numeral 2 denotes a cylindrical second roller, which presses against the first roller and rotates counterclockwise during fixing. It is conveyed from the right side by the conveyor belt 3,
The transfer paper P to which the unfixed toner T has adhered as a toner image is pressed and heated by the first roller 1 and the second roller 2 to be fixed, and is discharged to the left. Separation claws 4a and 4b are used to separate the transfer paper P to prevent it from being wrapped around the first roller 1 or the second roller 2 and causing transport failure.

The present invention newly adds the following structure to the heat roller fixing device described above. 5 is a cleaning roller which is separately provided and rotated by power, and 5a is a brush-like fiber planted on the circumferential surface of the cleaning roller 5. Reference numeral 6 denotes a release agent-impregnated member impregnated with a felt-like mold release agent, and 7 is a holding member corresponding to a receiving tray for the release agent-impregnated member 6.

One function of the release agent used here is to prevent soiling substances such as toner residue removed from the fixing roller from adhering to and accumulating on the cleaning roller. Another is to prevent offset development, that is, toner on the transfer paper from transferring to the fixing roller and degrading the image quality.

As the mold release agent used here, for example, silicone oil is suitable, and the felt or sponge-like mold release material impregnated member 6 is sufficiently impregnated with silicone oil having a high viscosity in the range of 1000 to 50000 CS.

The brush-like fibers 5a of the cleaning roller 5 are made of heat-resistant polyimide amide fibers, etc., and contact the first roller 1 with a biting depth of about 1 mm, and also contact the release material-impregnated member 6. are in a similar contact state. In such a structure, the cleaning roller 5 functions as an oil supply roller to the first roller 1 and has an oil supply control function. That is, since the fiber density at the center of the cleaning roller 5 is higher than that at the outer periphery, when the cleaning roller 5 is in a stopped state, the silicone oil impregnated in the release material impregnated member 6 passes through the brush-like fibers 5a by capillary action to the cleaning roller. 5. It is stored in the center and is kept on standby without flowing out to the outer periphery.

When copying is started, each roller group starts rotating, and the cleaning roller 5 also rotates.
Due to the rotation of the cleaning roller 5, the silicone oil that is in the center of the cleaning roller 5 gradually oozes out to the outer periphery due to centrifugal force, and the silicone oil is deposited in the center of the cleaning roller 5.
transition to. Therefore, excess silicone oil does not transfer to the first roller 1 all at once, and the release material is stably and uniformly applied on the circumferential surface of the first roller 1.

As described above, according to the present invention, the cleaning roller 5 has a brushing effect of removing toner adhering to the first roller 1, and also has an effect of uniformly applying the release material onto the circumferential surface of the first roller 1. The adhesion of toner on the roller 1 has been significantly reduced, and even if toner should have adhered to the circumferential surface of the first roller 1, it can now be removed extremely easily. In this way, the durability of the cleaning roller itself has become semi-permanent, and the reliability of the fixing device has also been greatly improved.

[Brief explanation of the drawing]

FIG. 1 is a schematic sectional view showing an embodiment of the present invention. 1...first roller, 2...second roller, 5...
Cleaning roller, 5a... brush-like fiber, 6
... Release material impregnated member, 7... Holding member.

Claims (1)

[Claims] 1. A cleaning roller around which heat-resistant fibers are implanted in a brush shape is brought into contact between both a heat fixing roller and a release agent-impregnated member impregnated with a release agent, and the cleaning roller and the heat fixation roller are The cleaning roller is provided to rotate with a speed difference at the point of contact with the roller, and the cleaning roller removes the toner on the heat fixing roller and supplies the release agent from the release agent impregnated member to the heat fixing roller. A heat roller fixing device configured to do so.