JPS5821263B2 - Method for manufacturing rollers for heat roller type fixing device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method of manufacturing a heating roller used in a heating roller type fixing device of an electrophotographic copying apparatus.

An electrophotographic copying apparatus employs a heat fixing method in which an electrostatic latent image formed on a photoreceptor is developed with a developer containing toner and then heated to melt and fix the toner image.

One of these thermal fixing methods involves inserting a recording paper carrying a toner image between a rotating heating roller and a rotating pressure roller that comes into contact with the heating roller, and records the image by melting the toner image using the heat from the roller. A heat roller type fixing device that fixes to paper is known.

Figure 1 is a schematic diagram of a typical heat roller type fixing device.
The heating roller 1 has the surface of a cylinder 110 made of a metal material such as aluminum coated with a resin layer 12 such as Teflon to provide release properties for toner (the toner on the recording paper is heated and melted).
In order to improve the property of preventing toner from adhering to the fixing roller, a heat generating lamp 13 such as a halogen lamp as a heat generating source is arranged inside.

The pressure roller 2 is a metal cylinder 210 whose surface is coated 22 with a rubber material such as silicone rubber, and the heating roller 1
is pressed against the surface with a weak force.

The heating roller 1 is rotationally driven at one shaft end by a drive device (not shown) and is supported pivotally at the other shaft end, while the pressure roller 1 is in pressure contact with the heating roller 1 and driven.

It has been empirically known that in such a heat roller type fixing device, in the initial stage of fixing, the toner has poor releasability and the toner locally adheres to the surface of the heat roller, staining the roller surface.

The reason for this is that the direction of the fine fibers that are thought to be generated on the Teflon-coated surface is not stable at the initial stage of fixing, and they are oriented in arbitrary directions. It is presumed that this is because areas with weaker sex are more likely to occur.

This decrease in releasability at the initial stage of fixing improves over time, but this is because the Teflon-coated surface is stimulated by cleaning means such as pressure rollers, recording paper, and plates as it is used, and the fibers change direction. This is presumed to be because the toner image is stabilized by being oriented in the same direction, so that the scratching effect on the toner image becomes smaller.

The present invention relates to a method for manufacturing a fiber-coated heating roller for improving the mold releasability in the initial stage of fixing, and will be described in detail below.

As another example, a method for manufacturing a heating roller coated with Teflon will be described.

A cylindrical aluminum material is cut to the length required for the heating roller, and the surface is rough-processed to improve the adhesion of Teflon.

A primer coating is applied to the surface of the roughly processed aluminum material to form an adhesive layer, and this layer is fired at about 380°C.

A Teflon emulsion liquid was sprayed onto the surface and baked at about 380°C.

This process of applying the Teflon liquid and baking is repeated several times to obtain the required film thickness and uniformity.

After a Teflon coating of the required thickness is thus formed, this coating is polished and finished.

This abrasive finishing process is a manufacturing process that has been commonly used up until now, in which the sandpaper is first abraded several times in order of coarseness, and then the abrasive finish is performed with soft cloth. In the finishing process, polishing was performed regardless of the rotational direction of the heated roller when it was used.

In the method of the present invention, the rotational direction of the heating roller during polishing is made to match the rotational direction when used in the fixing device, and the heating roller coated with Teflon, which has been polished in this way, is suitable for fixing. Even in the initial stage, it has excellent mold releasability and almost no toner stains occur.

Example Sample A: A Teflon coated heated roller was sanded five times with sandpaper and then polished with a soft cloth.

The direction of polishing is the same as the direction of rotation when using the roller.

Sample B: Polished under the same conditions as Sample A without specifying the polishing direction.

100 pieces of each sample were made.

These samples were installed in the fixing device under the following conditions, and using an all-black chart, copies were made on B-4 size transfer paper at 22 copies per minute for a total of 1000 copies, and the stains on the rollers were observed after completion. .

Fixing condition setting temperature: 200°C Heating roller diameter: 40φ Rotation speed: 60 RPM Roller pressure crab 1.5 kg/c1rL Pressure roller rubber hardness: 60° For sample B, 1 liter out of 100 had stains, and 37 had slight stains. Dirt has occurred.

However, sample A did not cause staining after 100 tests.

According to the present invention, when manufacturing a heating roller whose surface is coated with a resin such as Teflon, the direction of rotation of the roller in the polishing process is made to match the direction of rotation when the heating roller is used, thereby improving the speed during fixing. The releasability of the heating roller to the toner in the initial stage can be significantly improved.

Although it is difficult to determine the reason technically, it is thought that this is because the direction of the resin fibers is aligned in advance in a certain direction by polishing and is already in a stable state.

In this way, it is possible to eliminate toner stains on the heating roller and pressure roller during the initial stage of fixing, and it is possible to obtain high-quality copies.

In one form of copying apparatus, the surface of the heating roller of the fixing device is coated with a resin such as Teflon. Naturally, it is also possible to apply the present invention to rollers, and in this case as well, it is possible to improve the releasability of the pressure roller and prevent toner staining.

In addition to Teflon, resins used to improve mold releasability include FEP (a copolymer of 47-ethylene and 67-fluoropylene) and PFA (polyperfluoroalkylene), which are exactly the same as Teflon. It has been experimentally confirmed that this result can be obtained.

[Brief explanation of the drawing]

The accompanying drawing is a schematic diagram of a heating and pressure roller used in a heat roller type fixing device according to the present invention. 1... Heating roller, 11... Cylinder, 1
2...Resin layer, 13...Heating lamp,
2...Pressure roller, 21...Metal cylinder, 22...Coating.

Claims (1)

[Claims] 1 Consists of a rotating heating roller and a pressure roller that rotates while being in pressure contact with the heating roller, and a recording paper carrying a toner image is inserted between the two rollers to heat and melt the toner image and fix it on the recording paper. In a method for manufacturing rollers used in thermal roller type fixing devices, a resin liquid is applied to the surface of a cylindrical roller material made of a thermally conductive material to form a film to improve releasability against toner. . A method for manufacturing a roller, characterized in that the surface of the resin coating is polished while rotating the roller material in the same two directions as the rotational direction during fixing in a fixing device.