JPH0511564Y2 - - Google Patents

Description

[Detailed description of the invention] (Industrial application field) The invention is used in the technical field of fixing devices, and in particular prevents excessive temperature rise in a fixing roller in which a resistance heating layer is formed on a cylindrical base material. The present invention relates to a fixing roller device.

(Prior art) As a heating method for a cylindrical fixing roller, in contrast to the conventional indirect heating method using a halogen lamp, a method in which a resistance heating layer is provided on a cylindrical base material to directly heat the roller has recently been introduced. It is widely adopted. Since the fixing roller having such a resistance heating layer is directly heated, it takes less time from supplying power until the fixing roller reaches the set temperature under the same operating conditions than the indirect heating method described above. It has the advantage of being shorter. However, on the other hand, this method also has the problem that the so-called overshoot, which occurs when the temperature once greatly exceeds the set temperature and then drops to around the set temperature, is greater than that of the indirect heating method. Since the temperature rise gradient is large, measures must be taken to prevent excessive temperature rise in the event of an abnormality such as failure of the device. As a countermeasure, it is possible to use temperature fuses, thermoswitches, etc., but these methods have the problem of being difficult to control due to poor thermal response. Furthermore, if an attempt is made to increase the thermal conductivity by bringing a temperature fuse or the like into contact with it in order to improve its responsiveness, a problem arises in that it causes wear and scratches.

(Means for Solving the Problems) The present invention solves the problems of the conventional devices mentioned above, and provides a compact and inexpensive fixing device that does not require a special temperature detector, has excellent durability, and is compact and inexpensive. The purpose is to provide a roller device.

In order to achieve the above object, the present invention has a fixing roller in which a resistance heating layer is formed on a cylindrical base material, and the resistance heating layer is exposed on at least a part of the surface of the fixing roller. The present invention is characterized in that it has a power receiving part, a power feeding member is brought into sliding contact with the power receiving part, and the power feeding member is made of a material that melts at a certain temperature or higher.

(Example) Hereinafter, an example of the present invention will be described based on the accompanying drawings.

FIG. 1 is a partially cutaway perspective view of the device of this embodiment.

In the figure, reference numeral 1 refers to a core metal which is a base material and has a cylindrical shape, and step portions 1A are formed at both ends, and each layer to be described later is laminated between the step portions, and the fixing roller as a whole is finally formed by the step portions 1A. The outer diameter of the part is uniformly finished.

A heat-resistant insulating layer 2 is provided on the core metal 1. Examples of the material of the heat-resistant insulator include ceramic.

A resistive heating element layer 3 made of silicon carbide or the like is formed on the heat-resistant insulating layer 2, and a release layer 4 is applied thereon. The mold release layer 4 is not applied to both ends,
At both ends, the resistance heating layer 3 is exposed, forming a power receiving section 3A. In the figure, only the power receiving section 3A at the left end is shown, and the power receiving section at the right end is omitted.

A power supply member 5 made of a conductive material is in contact with the power receiving section 3A (the same applies to the other power receiving section). The power supply member 5 slides into contact with the fixing roller with a contact pressure that does not interfere with rotation during use. The power supply member is made of a material that melts above a certain temperature.

The above melting temperature may cause the surface of the fixing roller to rise excessively due to a malfunction or accident in the fixing device, temperature sensor, or device that drives the fixing device, causing damage to these devices and the fixing roller itself. It is limited to the upper limit temperature when there is.

In this embodiment as described above, the power supply member 5
The resistive heating element layer 3 receives electric power and generates heat, raising the temperature of the fixing roller. However, if the temperature rises excessively due to some kind of failure or accident and the fixing roller reaches the upper limit temperature, the power supply member 5 melts. As a result, the power supply is stopped and the fixing roller and other devices are protected.

The power supply member 5 can be made of lead, for example,
It is also possible to partially use a molten substance to make the contact surface with the power receiving part a conductive material with a small coefficient of friction.

(Effects of the invention) As described above, the present invention provides a fixing roller having a resistance heating layer on a cylindrical base material, in which a power supply member that supplies power to the resistance heating layer from outside the fixing roller is heated at a constant temperature. By using a material that melts as described above, it is possible to easily suppress the temperature rise when the temperature of the fixing roller increases abnormally, and as a result, damage to the fixing roller itself or other peripheral devices can be prevented. This has the effect that it can be prevented from occurring, and the structure for this purpose is extremely simple and can be manufactured easily.

[Brief explanation of the drawing]

FIG. 1 is a partially cutaway perspective view showing an embodiment of the present invention. DESCRIPTION OF SYMBOLS 1... Base material, 2... Heat-resistant insulating material layer, 3... Resistance heating element layer, 3A... Power receiving part, 4... Release layer, 5...
...Power supply component.

Claims (1)

[Claims for Utility Model Registration] (1) In a fixing roller having a resistive heating layer formed on a cylindrical base material, the resistive heating layer is a power-receiving device that is exposed on at least a part of the surface of the fixing roller. 1. A fixing roller device comprising: a power receiving portion; a power feeding member is brought into sliding contact with the power receiving portion; and the power feeding member is made of a material that melts at a certain temperature or higher. (2) The fixing roller device according to claim (1), wherein the resistance heating layer is formed with a heat-resistant insulating material layer interposed therebetween. (3) The fixing roller device according to claim 2, wherein the heat-resistant insulating material layer is made of ceramic material. (4) One of the utility model registration claims (1) to (3), characterized in that the fixing roller has a release layer formed on its surface except for at least the power receiving part. The fixing roller device described in .