JPH02285383A - Heat fixing roll device for electrophotographic device - Google Patents

Abstract

PURPOSE:To early and uniformly heat an entire surface by directly forming a resistance heating layer made of metal on the surface of a base resin layer laminated on the insulating layer of the heat roll or its surface with a film forming means. CONSTITUTION:For instance, from the center to the outer periphery of the heat roll 11, a metallic rotary shaft 15, the insulating layer 16 composed of ceramic material, the resistance heating layer 18 connected to an outer light source, and a protecting layer 19 composed of fluororesin are laminated. Then, metal such as Ni, Ni-Cr, Ni-P, and Ni-b is used for electroless plating to directly form the heating resistance layer 18 on the surface of the insulating layer 16. Therefore, the thickness of the heating layer 18 of the heat roll 11 is uniformed as much as possible, and the heating layer 18 is always heated uniformly.

Description

Detailed Description of the Invention [Objective of the Invention (Industrial Field of Application)] The present invention relates to an electrophotographic apparatus that fixes a mapped image by heating and pressing toner onto a transfer medium using a pair of rolls. The present invention relates to a heat fixing roll device.

<Prior Art> Conventionally, in an electrophotographic apparatus using an electrophotographic process such as a copying machine, in order to fix toner after transferring it to a transfer medium such as paper, a heat generating unit such as a heat generating lamp or the like is used. A heating roll having a cylindrical member made of a good heat conductor such as a metal at the center and surrounding this heat generating part, and a pressure roll having an elastomer material such as synthetic rubber fitted on the outside are brought into close contact with each other, and both rolls are placed in close contact with each other. The above-described transfer means is passed through the contacting nip portion, and the toner is heated and simultaneously pressed against the transfer means.

However, such a heat fixing roll device can be used when the heat from the heat generating part in the heating roll is transmitted to the outer circumferential cylindrical member and the temperature of this heat conductor rises to a predetermined temperature. Since there is a gap between the roll and the cylindrical member, thermal efficiency is poor, and the heat capacity of the heating roll is large, so it takes a relatively long time to raise the temperature.

Therefore, the above-mentioned problems can be solved by forming the pressure roll from a hard material that is a good heat conductor and by forming the heating roll from a resin-based resistance heating layer that is easily elastically deformable. In that case, as described in Japanese Patent Application No. 62-309339 filed by the same applicant, the heating layer described above is made of a heat-resistant resin such as polyimide, epoxy, or silicone containing metal powder. It is conceivable that such a resin-based heat generating layer has an unstable resistance value due to non-uniform thickness of the layer, and cannot always obtain a suitable amount of heat generated.

<Problems to be Solved by the Invention> In view of the problems of the prior art, the main object of the present invention is to provide a heat fixing roll for an electrophotographic apparatus in which the heating roll can quickly rise in temperature and can always generate heat appropriately. The goal is to provide equipment.

[Structure of the Invention] Means for Solving the Problems According to the present invention, the object is to pass a transfer means between a heating roll and a pressure roll that rotate in close contact with each other, and to A heat fixing roll device of an electrophotographic apparatus for fixing an image on the transfer target means, wherein the heating roll includes a heat insulating layer and a surface of the heat insulating layer, or a base resin layered on the surface of the heat insulating layer. This is achieved by providing a heat fixing roll device for an electrophotographic apparatus, characterized in that the layer has a resistance heating layer made of metal that is directly formed by a film forming means.

<Function> By doing so, the thickness of the heat generating layer of the heating roll can be made as uniform as possible, and the heat generating layer always generates heat uniformly.

<Embodiments> Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

FIG. 1 shows the configuration of a heat fixing roll device of an electrophotographic apparatus to which the present invention is applied.

The rotatable photosensitive drum 1 has an outer peripheral surface plated with selenium. A charging section 2, a photosensitive section 3, a developing section 4, a transfer section 5, a cleaning section 6, and a static eliminating section 7 are provided along the outer peripheral surface of the photosensitive drum 1 in this order. Further, a fixing section 8 is provided downstream in the direction in which the transfer paper 9 is carried out from the transfer section 5, that is, in the direction of arrow A.

When the photosensitive drum 1 rotates in the direction of arrow B in FIG. 1, the surface of the drum passes through a charging section 2 consisting of corona charging means, and as a result, the drum surface reaches a uniform potential of about 700 volts. charged. Next, the surface portion of the photosensitive drum 1 passes through an exposure section 3, and a latent image corresponding to the shape of the subject is formed by exposure. Then, toner conveyed to a carrier (not shown) in the developing section 4 adheres to the surface of the photosensitive drum 1 in correspondence with the latent image. Further, in the transfer section 5, the transfer paper 9, which is conveyed in the direction of arrow A from the right side in FIG.
At the same time as being charged by a, the toner adhering to the surface portion of the drum 1 is transferred onto the paper 9. The surface portion of the photosensitive drum 1 after the toner has been transferred passes through a cleaning section 6, and residual toner is cleaned off. And a static eliminator 7 consisting of an exposure lamp
At this point, the electric potential is removed to approximately - in the axial direction, and the above process is repeated again. On the other hand, the toner transferred to the paper 9 is heated and pressed onto the paper 9 at the same time in the fixing section 8, so that the image is fixed on the paper 9.

FIG. 2 is an enlarged view of the main part of FIG. 1 showing a first embodiment of the heat fixing roll device according to the present invention. The fixing unit 8 includes a pressure roll 10 that is rotationally driven by a driving means (not shown) and a heating roll 11 that is driven by being in close contact with the pressure roll at a contact portion 12. Crimping roll 10
It consists of a cylindrical rotating shaft 13 made of metal, and an elastic layer 14 made of a rubber roll wrapped around the outer periphery of the rotating shaft 13.

On the other hand, from the center to the outer circumference of the heating roll 11,
A rotating shaft 15 made of metal and a heat insulating layer 1 made of ceramic material
6, and a resistance heating layer 1 connected to an external power source (not shown).
8 and a protective layer 19 made of fluororesin are laminated in this order. Further, an adhesive layer is formed between the resistance heating layer 18 and the protective layer 19. This adhesive layer changes from the resistance heating layer 18 to the protective layer 19 during operation of the heating roll 11.
This is a layer to prevent the film from peeling off.

Here, the resistance heating layer 18 is made of Nf, Ni-Cr.

A metal such as N1-P or N1-b is directly formed on the surface of the heat insulating layer 16 by electroless plating. In fact, the resistance heating layer may be formed using a known film forming method such as vacuum evaporation or sputtering.

The heat generated from the resistance heating layer 18 is transferred to the heat insulating layer 1 on the inner periphery.
6, most of the heat is emitted outward in the radial direction, and the surface of the heating roll 11 quickly rises in temperature, and the temperature of the heating roll 11 becomes negative in both the axial and circumferential directions. Therefore, the toner can be fixed to the transfer paper 9 quickly and suitably.

Here, when using a conventional resistance heating layer containing metal powder in polyimide or epoxy resin, the thickness of the core layer tends to be uneven, so the resistance value varies in the circumferential direction and the axis. However, in the heat fixing roll device of this embodiment, by forming the resistance heating layer 18 directly on the surface of the heat insulating layer 16 by electroless plating, the thickness of the layer is uniform in the circumferential direction and the axial direction. The resistance value becomes uniform along the line.

FIG. 3 is a diagram similar to FIG. 2 showing a second embodiment based on the present invention. Note that parts in this embodiment that are similar to those in the first embodiment are given the same reference numerals, and detailed explanation thereof will be omitted.

In this embodiment, the heat insulating layer 26 of the heating roll 21 is made of a foamed material such as calcium silicate or silicone foam rubber, and the surface of the core layer is made of polyimide resin, polyphenylene sulfide resin, polyether sulfone resin, polyether ether ketone resin, etc. A base resin layer 27' made of a heat-resistant resin material such as the following is laminated. A resistance heating layer 28 is formed on the surface of this base resin layer 27 by electroless plating.

The other configurations are generally similar to the first embodiment.

[Effects of the Invention] As described above, according to the present invention, by directly forming a resistance heating layer made of metal using a film forming means on the surface of the heat insulating layer of the heating roll or the base resin layer laminated on the surface thereof, The thickness of the resistance heating layer of the heating roll is made uniform along the axial direction and the circumferential direction, the resistance value thereof is made uniform, and the temperature increases quickly and uniformly over the entire surface. Therefore, since the image quality of electrophotography is improved, the effects of the present invention are extremely large.

[Brief explanation of drawings]

FIG. 1 is a schematic configuration diagram of an electrophotographic apparatus to which a heat fixing roll device for an electrophotographic apparatus according to the present invention is applied. 2 is an enlarged cross-sectional view of the main part of FIG. 1 showing a first embodiment based on the present invention. FIG. 3 is an enlarged sectional view of a main part of FIG. It is a similar diagram. 1... Photosensitive drum 2... Charging section 3... Exposure section 4... Developing section 5... Transfer section
5a...Charging section 6...Cleaning section 7...Static elimination section 8...Fixing section 9...Transfer paper 10
...Crimping roll 11...Heating roll 12...
Contact portion 13... Rotating shaft 14... Elastic layer
15... Rotating shaft 16... Heat insulation layer 18.
...Resistance heating layer 19...Protective layer 21...Heating roll 26...Insulating layer 27...Base resin layer 28...Resistance heating layer

Claims (3)

[Claims] (1) A heat fixing roll device of an electrophotographic apparatus for fixing an image of a subject on the transfer means by passing a transfer means between a heating roll and a pressure roll that rotate in close contact with each other, A heat fixing roll device for an electrophotographic apparatus, wherein the heating roll has a heat insulating layer and a resistance heating layer made of metal that is directly formed on the surface of the heat insulating layer using a film forming means. (2) A heat fixing roll device of an electrophotographic apparatus for fixing an image of a subject on the transfer means by passing a transfer means between a heating roll and a pressure roll that rotate in close contact with each other, The heating roll has a heat insulating layer made of a foamed material, a base resin layer laminated on the surface of the heat insulating layer, and a resistance heating layer made of metal formed directly on the base resin layer using a film forming means. A heat fixing roll device for an electrophotographic device, characterized in that: (3) A heat fixing roll device for an electrophotographic apparatus according to claim 1 or 2, wherein the film forming means comprises electroless plating.