JPH07302010A - Heating roller for fixing - Google Patents

Abstract

PURPOSE:To install a power feeding part which can be easily manufactured, having excellent durability and high reliability in a heating roller for fixing provided with a resistance heating body layer on its surface. CONSTITUTION:The resistance heating body 12 is installed on the surface of a cylindrical core body 10, and a ring-like electrode 20 is fitted to the end part of the resistance heating body 12, the ring-like electrode 20 is constituted of an internal ring 16 and an external ring 18 which can be fitted to the internal ring 16, and a tapered external thread 26 is arranged on the fitting part of the internal ring 16 with the external ring 18, and also, an internal thread 30 is arranged on the fitting part of the external ring, besides, notches 27 are formed on a part of the internal ring 16 in parallel to a fitting direction. Thus, by fitting the external ring 18 on the internal ring 18 and screwing it after fitting the internal ring 16 on the desired position on the resistance heating body 12, the internal ring 16 is pushed against the heating roller body to be fixed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fixing heating roller used in a heat fixing device in an image forming apparatus such as a copying machine, a printer or a fax machine.

[0002]

2. Description of the Related Art Conventionally, in a fixing device of an image forming apparatus using an electrophotographic technique, a toner image is supported by a heating roller heated to a predetermined temperature and a pressure roller pressed against the heating roller. A heat roller system in which a toner image is fixed on a recording material by heating while sandwiching and conveying the recording material is often used. A halogen lamp is mainly used as a heat source for the heating roller, but it has a drawback that the heat efficiency is poor and it takes a long time to reach a predetermined temperature.

In order to make up for this drawback, a number of methods have been proposed in which a resistance heating element is formed on the surface of the heating roller and an electric current is passed through the resistance heating element to generate heat and the surface is directly heated. This method is temporarily called a surface heating method. In this method,
It is necessary to form ring-shaped electrodes at both ends of the resistance heating element layer and supply electric power from external electrodes that are in sliding contact with each other. As a method of forming this electrode, there have been used a method of shrink-fitting a metal ring, a method of coating a metal by using arc discharge, a method of applying a metal paste and firing.

[0004]

However, the method of shrink-fitting the metal ring requires a tight tolerance between the outer diameter of the heat roller body and the inner diameter of the metal ring, or the electrode ring must be heated to a high temperature of several hundred degrees during fitting. Since it must be carried out while it is held, work efficiency is poor and dangerous. In addition, the method of coating a metal by using arc discharge requires high voltage and requires special equipment. Further, the electrode made of the metal paste has a problem in durability and cannot withstand sliding for a long period of time.

The present invention has been made to solve the above-mentioned problems, and is easy to manufacture and has excellent durability.
It is an object of the present invention to provide a fixing heating roller provided with a highly reliable power feeding unit.

[0006]

In order to achieve this object, a fixing heating roller of the present invention is provided with a resistance heating element layer on the surface of a cylindrical core, and a ring-shaped resistance heating element layer end portion. A fixing heating roller having electrodes fitted therein, wherein the ring-shaped electrode comprises an inner ring and an outer ring that can be fitted to the inner ring, and at least one of the inner ring and the outer ring has a tapered shape. In addition, the inner peripheral ring is characterized in that at least a part of the fitting portion with the outer peripheral ring is provided with a cut parallel to the fitting direction.

[0007]

In the fixing heating roller of the present invention having the above-described structure, the inner peripheral ring is fitted and arranged at a desired position on the resistance heating element layer, and then the outer peripheral ring is fitted and screwed to fix the inner peripheral ring. The ring is pressed against the heating roller body and fixed.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. First, the structure of the heating roller will be described with reference to FIG. FIG. 1 is a perspective view and an enlarged sectional view of a fixing heating roller of the present invention. In the fixing heating roller of this embodiment, the insulating layer 12 is formed on the surface of the core body 10 made of aluminum. It is also possible to use other metals such as stainless steel and copper as the material of the core body. Insulation layer 1
As the material of 2, for example, a polyimide resin having high heat resistance is suitable. It is also possible to use an alumina film, and if the core body 10 is made of an insulating material such as ceramics, the insulating layer becomes unnecessary.

A resistance heating element layer 14 is formed on the insulating layer 12, and the material thereof may be, for example, a polyimide resin mixed with a conductive material. Also,
It may be a ceramic heating element or a metallic heating element such as nickel or chromium. Ring-shaped electrodes 20 in which an inner peripheral ring 16 and an outer peripheral ring 18 are combined are attached to both ends of the resistance heating layer 14. Further, a peeling layer 22 is formed on the upper layer of the resistance heating element layer, which serves as both insulation and protection of the resistance heating element, except where the electrodes are attached. The peeling layer 22 prevents the recording paper from being wound around the heating roller, and is generally made of a fluorine resin.

Next, referring to FIG. 2, the ring-shaped electrode 20.
The structure of will be described. As described above, the ring-shaped electrode 2
0 is composed of two combinations of the inner ring 16 and the outer ring 18. It is desirable that the material be a conductor such as aluminum and a metal having excellent workability. Inner ring 1
The inner diameter of 6 is set to a size such that it can be fitted smoothly into the heating roller main body in which the resistance heating layer 14 is applied without any gap. A taper male screw 26 is formed on the inner ring, leaving the end guide portion 24. A notch 28 for tightening a screw is formed in the guide portion 24 and can be fixed in the circumferential direction by using an appropriate jig. The taper male screw 26 has a notch formed in at least one position in a direction perpendicular to the circumferential direction of the screw, and has a structure in which the inner diameter is reduced when a force is applied in the inner diameter direction of the ring.

A parallel female screw 30 is formed on the outer peripheral ring 18 and is paired with the taper male screw 26 of the inner peripheral ring 16, and a notch 3 into which a jig is fitted when the screw is tightened.
2 is formed. When the notch 28 of the inner peripheral ring 16 is fixed and the notch 32 of the outer peripheral ring 18 is fitted into the jig and rotated in the direction in which the screw is tightened, the inner diameter of the inner peripheral ring 16 is gradually reduced, resulting in resistance heating. The heat roller body on which the body layer 14 is formed is tightened. As a result, the ring upper electrode 20 including the inner ring 16 and the outer ring 18 is formed.
Is fixed in a state where the resistance heating element layer 14 is electrically connected.

Since the heating roller must be supplied with electric power while rotating, the conductive brush 34 is installed on the outer diameter portion of the outer ring 18 of the ring upper electrode 20 so as to always be in sliding contact. Further, in order to suppress wear of the conductive brush 34 and reduce contact resistance, the outer ring 1
It is desirable that the sliding portion 36 of No. 8 has a small surface roughness. In any case, since it is a very strong and thick electrode as compared with a sliding electrode formed of a metal paste or a metal coating, durability does not matter at all.

In this embodiment, the inner peripheral ring has a tapered male screw and the outer peripheral ring has a parallel female screw. However, as the screws are tightened, the inner diameter of the inner peripheral ring is reduced and fixed to the heating roller body. Any structure will do. Therefore, the inner peripheral ring may be parallel male threads and the outer peripheral ring may be tapered female threads, or both may be tapered threads.

The shape of the notch for tightening the screw may be formed in an appropriate shape according to the jig to be used.

It is important to fix the ring-shaped electrode by fitting the outer peripheral ring to the inner peripheral ring, and the inner peripheral ring and the outer peripheral ring do not necessarily have to have the threaded portion. For example, even if the inner ring has a tapered shape without a threaded portion and the outer ring has a simple ring shape without a threaded portion, the inner diameter of the inner ring will be It is reduced and fixed to the heating roller body. In addition, if at least one of the inner ring and the outer ring has a tapered shape, the object of the present invention can be achieved by variously changing the fitting method.

Further, in the above embodiment, the ring-shaped electrode 2
0, both the inner peripheral ring 16 and the outer peripheral ring 18 are made of a conductor such as aluminum, but only the inner peripheral ring 16 is made of a conductor such as aluminum and the outer diameter portion of the inner peripheral ring 16 is
There is no problem even if the conductive brush 34 is always in sliding contact.

[0017]

As is apparent from the above description, according to the fixing heat roller of the present invention, the electrode for supplying electric power to the resistance heating element on the surface of the heat roller can be simply formed by tightening the screw. It is possible to form a sliding electrode which can be installed on the substrate and has no problem in durability.

[Brief description of drawings]

FIG. 1 is a perspective view and an enlarged cross-sectional view of a fixing heating roller of the present invention.

FIG. 2 is a diagram of a ring-shaped electrode portion of the fixing heating roller of the present invention.

[Explanation of symbols]

 10 core body 12 resistance heating element 16 inner ring 18 outer ring 20 ring electrode 26 taper male screw 27 notch 30 female screw

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Office reference number FI technical display location H05B 3/00 335

Claims (3)

[Claims] 1. A fixing heating roller in which a resistance heating element layer is provided on the surface of a cylindrical core body, and a ring-shaped electrode is fitted and installed at an end of the resistance heating element layer, wherein the ring-shaped electrode has an inner circumference. It consists of a ring and an outer ring that can be fitted to the inner ring, and at least one of the inner ring and the outer ring has a taper shape, and the inner ring fits at least a part of the fitting part with the outer ring. A fixing heating roller having a notch formed in parallel with the mating direction. 2. The fixing heating roller according to claim 1, wherein the inner peripheral ring has a male screw in a fitting portion with the outer peripheral ring, and the outer peripheral ring has a female screw. A fixing heating roller, wherein at least one screw of the outer peripheral ring is a taper screw, and a notch parallel to the fitting direction is formed in at least a part of the male screw portion of the inner peripheral ring. 3. The fixing heating roller according to claim 1, wherein at least the inner peripheral ring is formed of a conductive member.