JPH09171318A - Separating pawl of fixing device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To form a fluororesin sheet on the surface of a separating pawl which peels the transfer paper adhering to a heating roller without sintering the sheet at a high temp. and to obtain the separating pawl for a fixing device with which cost reduction is embodied by adhering and integrating the fluororesin sheet to at least the paper passage surface of the separating pawl. SOLUTION: The rear surfaces of the separating pawls 17 brought into sliding contact with the outer peripheral surface of the heating roller 15 are brought into sliding contact with the outer peripheral surface under a prescribed pressure by an energizing means. The transfer paper which enters a nip part and adheres to the peripheral surface of the heating roller 15 may, therefore, be forcibly separated. At this time, the paper passage surfaces of the separating pawls (consisting of non-heat resistant resin materials of a low cost; for example, polyethylene sulfite PPS, polyamide imide PAI, PEEK, etc.) 17 are rubbed against the toner image on the transfer paper and, thereby, toner adheres thereto. The paper passage surfaces of the separating pawls 17 are coated and integrated with the fluororesin sheets having a high surface release property by primers (adhesives) in order to prevent such toner adhesion, thereby, the release property is enhanced.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improvement of a resin separating claw used for separating transfer paper from the peripheral surface of a heating roller in an electrophotographic heat roller fixing device. The present invention relates to a separation claw of a fixing device that can prevent toner from adhering to a processed surface.

[0002]

2. Description of the Related Art A fixing device such as an electrophotographic copying machine, a printer, a facsimile device, or the like includes a heating roller having a heater therein and a pressure roller which is rotated while being pressed against the outer peripheral surface of the heating roller. The unfixed toner on the transfer paper passing through the nip portion between the rollers is heated while being pressed, so that the toner is impregnated into the fibers of the transfer paper and fixed. The unfixed toner on the transfer paper comes into contact with the outer peripheral surface of the heating roller when the paper is passed, so the transfer paper easily adheres to the outer peripheral surface of the heating roller, and the separation claw for separating the transfer paper is located downstream of the nip portion. Is in sliding contact with the peripheral surface of the heating roller. If toner adheres to the separating claw, the peeling property deteriorates.
Various processes are applied to the resin separation claws in order to prevent adhesion of toner. For example, Shokai 60-2
In the "Fixing device" of Japanese Patent No. 1755, a coating made of a heat-resistant material having a good mold releasability is provided on at least the side of the separation claw base that serves as a guide surface for the toner image support material, and the thickness of the coating is set to the tip of the separation claw. The technology that is thicker is disclosed as it is closer to. Also,
"Separation claw for copying machine" in Japanese Patent Laid-Open No. 62-157074
Discloses a technique in which the separation claw is coated with a fluorine compound having a polar group having a high affinity with the surface of the base material resin of the separation claw.

[0003]

As described above, a resin separating claw is required for peeling off the transfer paper to which the unfixed toner is attached from the heating roller, but the separating claw is also used. Since the toner adheres to the toner, which tends to cause defective separation and image stains, a fluororesin coating is provided at appropriate places on the separating claw to enhance releasability. In the conventional fluororesin coating method, a liquid fluororesin is sprayed or coated on the nail at a proper position, but the surface of the fluororesin layer coated by this method has many irregularities and the releasability is not good. . Therefore, conventionally, the melting point of the fluororesin is 3
The surface was smoothed by heating to 80 ° C. or higher and once melting. However, if the fluororesin is fired at about 380 degrees, the resin that is the base material of the separation claw may be deformed, and the firing temperature may be increased in order to prevent the separation claw from being deformed. This was not possible, and the fluororesin had to be fired at a low temperature. For this reason, the surface of the fluororesin layer was not smooth and the toner was likely to adhere. There is also a method of forming a separating claw with a resin having heat resistance, but since heat-resistant resin is expensive as is well known, it is the fact that each company cannot adopt it.
The present invention has been made in view of the above, and an object of the present invention is to provide a separation claw of a fixing device in which the fluororesin layer formed on the surface of the separation claw is formed without firing at high temperature, and further cost reduction can be realized. There is.

[0004]

According to a first aspect of the present invention, there is provided a fixing device which performs thermal fixing by passing a transfer paper sheet on which a toner image formed on a photosensitive member has been transferred, through the transfer paper. A fluororesin sheet is attached to at least the paper-passing surface of the separation claw that separates the transfer paper adhered by sliding contact with the peripheral surface of the heating roller.
It is characterized in that the adhesive is integrated into one. A second aspect of the invention is characterized in that the material of the separation claw is PPS, PAI, or PEEK.

[0005]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described in detail with reference to embodiments shown in the accompanying drawings. FIG. 1 is an overall configuration diagram of a printer as an example of an image forming apparatus including a fixing device to which the present invention is applied. In the figure, reference numeral 1 is a printer main body, 2
Is a paper feed cassette provided in the printer body 1. The transfer paper P fed from one of the paper feed cassettes 2 in the direction of arrow A is conveyed to the drum-shaped photoconductor 4 by the registration roller pair 3 at a timing. The photosensitive member 4 is driven to rotate clockwise and the surface thereof is uniformly charged by the charging charger 5, and an electrostatic latent image is formed on the photosensitive member 4 by irradiation of laser light from the laser optical system 6. . This latent image is developed by the developing device 7.
When it passes through, the toner forms a visible image, and this visible image is transferred onto the transfer paper P that is conveyed to the transfer charger 8 of the photoconductor 4. The visible image on the transfer paper P that has been transferred is fixed by the fixing device 9. Transfer paper P exiting the fixing device 9
Is discharged to the paper discharge unit 10 in the arrow B direction, for example. On the other hand, the residual toner is removed from the photoreceptor 4 after the transfer of the visible image by the cleaning device 11.

Next, the fixing device 9 will be described with reference to FIG. In the casing of the fixing device 9, a heating roller 15 having a heater therein and a pressure roller 1 are provided.
6 is arranged, and the pressure roller 16 is provided to rotate the heating roller 15.
The rollers are in pressure contact with each other on their outer peripheral surfaces so that they rotate together. The toner on the transfer paper P to which the toner is attached at the transfer position of the transfer jersey 8 is melted by the heat given by the heating roller 15. When the toner melts, tackiness occurs and the transfer paper P tries to adhere to the surface of the heating roller 15. However, the separation claw 17 slidably contacted with the outer peripheral surface of the heating roller 15 is rotated by a holding portion (not shown). The lower surface of the separation claw is slidably contacted with a predetermined pressure by urging means (not shown) so as to be movably supported. Therefore, it is possible to forcibly separate the transfer paper P that has entered the nip portion in the direction of the arrow and adhered to the peripheral surface of the heating roller. At this time, separating nails (non-heat resistant low cost resin material such as polyethylene sulfite PPS, polyamide imide PAI, peak PEE
The sheet passing surface of the separation claw 17 (e.g., K, etc.) 17 rubs against the toner image on the transfer sheet, so that the toner adheres, but in order to prevent this, in this embodiment, as shown in FIG. The fluorine resin sheet 18 having a high surface releasability is integrally coated on the paper surface with a primer (adhesive) to enhance the releasability. As the fluororesin sheet 18, a sheet which is heated to about its melting temperature (for example, 380 ° C.) when it is formed into a sheet and has improved mold release is used.

In this embodiment, as a method of coating the fluororesin sheet 18, the fluororesin sheet 18 is integrally coated on the outer surface of the separation claw 17 with a primer 19 as shown in FIG. The covering portion is at least the paper passing surface, but since it is not appropriate to cover only the paper passing surface from the adhesive strength of the sheet, it is preferable to adhere the sheet to the separation claw portion other than the paper passing surface. Alternatively, a tube-shaped sheet formed by shaping the sheet into a cylindrical shape may be covered with a primer from the tip of the separation claw up to a predetermined range and then bonded with a primer.
When the fluororesin sheet 18 is coated on the separating claw 17, it is sufficient that at least the paper passing surface is coated so as not to have wrinkles, and then the primer 70 is used for adhesion. In other words, even if some wrinkles are generated on the portion other than the sheet passing surface, there is no problem and the workability is extremely good and the coating can be performed easily. After the completion of coating, the primer is stabilized and the shape of the separation claw 17 is stabilized at an temperature of about 100 to 150 ° C. using an electric furnace or the like. When a fluororesin sheet (including a tube-shaped one) is adhered to a separating claw using a primer, it can be used as it is, but it should be heated in an electric furnace to heat-shrink the fluororesin sheet. Thereby, the adhesive force can be stabilized.

[0008]

As described above, according to the invention of claim 1,
At least the paper-passing surface of the separating claw is covered (adhered) with a fluororesin sheet (including the tube) whose release property is adjusted to a high level beforehand, so the surface state of the paper-passing surface becomes smooth and toner adheres. Can be prevented. Further, after the bonding, the fluororesin sheet is heated to cause thermal shrinkage, so that a more stable coating state can be obtained. According to the invention of claim 2, since a non-heat-resistant and low-cost resin material such as polyethylene sulfite PPS, polyamide imide PAI, or peak PEEK is used as the base material of the separating claw, the fluororesin is smoothly baked. However, since the fluororesin layer is formed by the adhesive, an inexpensive separation claw having a smooth release layer can be obtained without firing.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of an example of an image forming apparatus including a fixing device to which the present invention is applied.

FIG. 2 is an enlarged perspective view of a main part of the fixing device in FIG.

FIG. 3 is a partial configuration diagram of the separation claw of the present invention.

FIG. 4 is a diagram showing a procedure for covering the separation claw of the present invention with a fluororesin sheet.

[Explanation of symbols]

1 printer body, 2 paper feed cassette, 3 registration roller pair, 4 photoconductor, 5 charging charger, 6 laser optical system, 7 developing device, 8 transfer charger, 9 fixing device,
10 paper discharge part, 11 cleaning device, 15 heating roller, 16 pressure roller, 17 separating claw, 18 primer (adhesive), 19 primer.

Claims (2)

[Claims] 1. A fixing device for performing thermal fixing by passing a transfer paper, on which a toner image formed on a photoconductor has been transferred, through sliding contact with a peripheral surface of a heating roller constituting the fixing device. A separating claw for a fixing device, characterized in that a fluororesin sheet is integrally bonded to at least the paper passing surface of the separating claw for peeling off the attached transfer paper. 2. The material of the separation claw is PPS, PAI, P
The separation claw of the fixing device according to claim 1, wherein the separation claw is EEK.