JPH0434434Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Technical Field of the Invention] The present invention relates to a temperature sensor that detects the surface temperature of a rotating body such as a fixing roller of a heat fixing device provided inside a copying machine.

[Technical background of the invention and its problems]

A temperature detection device for detecting the surface temperature of an aluminum cylindrical fixing roller whose surface is coated with Teflon used in a heat fixing device of an electronic copying machine includes a temperature sensor that is brought into direct contact with the surface of the rotating fixing roller. The most effective method was to detect the

As such a method, a temperature sensor described in Japanese Utility Model Publication No. 59-39625 is known.

This temperature sensor is made of flexible resin such as vinyl chloride, polyester, polyethylene, polyimide, or fluorine resin with a thickness of 25 to 200 μm.
A so-called flexible printed circuit board is used, in which two conductor foils are formed on an insulating thin film sheet, and an insulating thin film sheet made of the same material as the above-mentioned insulating thin film sheet is further formed thereon by a method such as adhesion.

Then, an opening is formed in this insulating thin film sheet, a heat-sensitive element is mounted thereon, a part of the flexible printed circuit board is held by a holder, and the part of the heat-sensitive element is brought into close contact with the surface of the rotating body. It is.

Thereby, the temperature of the rotating body is transmitted to the heat-sensitive element via the thin insulating thin film sheet, making it possible to accurately detect the temperature.

However, since this temperature sensor is constructed from a flexible printed circuit board, its flexibility does not allow for sufficient contact pressure against the rotating body. If the temperature is increased too quickly, the flexible printed circuit board will vibrate, and the heat-sensitive elements will not be in perfect contact with each other, making accurate temperature detection impossible.

In addition, since the temperature sensor is thin, it has to be held in the holder by bending or caulking the metal plate that is the holder, or by fixing it with a fixing device such as an eyelet, resulting in high accuracy. It was also difficult to assemble and downsize.

[Purpose of invention]

The present invention is intended to eliminate the above-mentioned drawbacks of conventional temperature sensors, and even when the rotation speed of the fixing roller is increased due to an elastic insulating substrate such as a polyimide resin glass laminate, the present invention provides a sufficient temperature sensor. The purpose of the present invention is to provide a temperature sensor that always maintains a close contact state by contact pressure, enables accurate temperature detection, can be assembled with high precision to a holder, and can be miniaturized. It is something.

[Example of idea]

An embodiment of the present invention will be described below with reference to the drawings.

1 is an elastic insulating substrate such as a polyimide resin glass laminate with a thickness of 0.4 mm, and at least two conductor foils 2 and 2' such as copper foil are printed on one side of the substrate. An opening 3 is formed between and adjacent to the conductor foils 2, 2'.

A heat-sensitive element 4 is inserted into the opening 3, and its lead wires 5, 5' are electrically connected to the conductive foils 2, 2'. As this connection method, welding is used when used at high temperatures, but soldering may be used in other cases.

A lead wire 6 for external connection is electrically connected to the other ends of the conductive foils 2, 2' by soldering.

Reference numeral 7 designates a tube for fixing the lead wire 6 to the substrate 1, and the substrate 1 is provided with a protruding piece 8 for fitting the tube 7, the tip of which has a tapered hook portion 8'. When the tube 7 fitted to the leader wire 6 is fitted to the protrusion 8, the tube 7 is attached to the hooked part 8'.
The base end of the lead wire 6 is fixed to the substrate 1.

On the opposite side of the substrate 1 on which the conductor foils 2 and 2' were formed,
In order to make smooth contact with the rotating fixing roller and prevent scratches on the surface of the fixing roller, an anti-friction thin film sheet 9 made of polyimide resin, silicone resin, fluorine resin, etc. is used as an adhesive or other means. It will be arranged in

The thickness of this thin film sheet 9 is suitably about 25 to 200 μm in order to satisfy both abrasion resistance and thermal responsiveness, and the material is polyimide resin or fluorine resin in addition to the above-mentioned resins. Carbon inside,
graphite, molybdenum disulfide, boron nitride,
If at least one kind of fine powder of anti-friction material such as alumina is added, the wear resistance and thermal response will be further improved.

This thin film sheet 9 covers the aperture 3 and therefore protects the heat sensitive element 4.
It is also possible to improve the thermal response by filling the space between the openings 3 with silicone rubber or a resin with good thermal conductivity.

Furthermore, in order to protect the heat-sensitive element 4, a thin film sheet 10 is adhered to and coated on the conductor foils 2 and 2' of the substrate 1 to also serve as protection for the conductor foils 2 and 2', or an insulating resin is coated. The conductor foils 2, 2' may also be protected.

Alternatively, when a fluid such as grease is introduced into the opening 3, the thin film sheet 10 serves to seal it.

The substrate 1 formed as described above is held by a holder 11 formed of a metal plate, but the holder 11 is not limited to the shape and structure shown in FIG. , which can be freely modified depending on the mounting method and mounting space of the temperature sensor.

Further, since the substrate 1 is an elastic body as described above, it has sufficient elasticity, so if there is a limitation in the mounting space, a hole for mounting can be provided in the substrate 1 and the fixing roller can be directly supported. It is also possible to attach it to the frame with screws or the like, and in this case, the holder 11 is not required.

Furthermore, if there is a possibility that the coating surface of the fixing roller may be damaged by the corners of the substrate 1, the thin film sheet 9 should be made large enough to protrude outside the substrate 1 as shown in FIG. 4 to prevent this. You can also do it.

[Effect of idea]

As described above, in the present invention, a heat-sensitive element is placed in the opening of an insulating substrate having heat resistance and elasticity, and a heat-resistant thin film sheet is bonded to the back surface of the insulating substrate. Therefore, heat conduction to the heat-sensitive element is good, and a temperature sensor with excellent thermal response characteristics can be obtained. Since the lead wires of the elements are connected, the heat-sensitive element can be easily fixed to the insulating substrate, and there is no fear of breakage of the lead wires.

[Brief explanation of the drawing]

The drawings show one embodiment of the present invention, in which Fig. 1 is a plan view of an insulating substrate, Fig. 2 is a vertical cross-sectional view of the heat-sensitive element section, Fig. 3 is a slope view, and Fig. 4 is a diagram of another embodiment. It is a perspective view of the main part of a state. 1... Insulating substrate, 2, 2'... Conductor foil, 3...
Opening portion, 4... Heat-sensitive element, 5... Lead wire of heat-sensitive element, 6... Lead wire for external extraction, 9... Thin film sheet.

Claims (1)

[Scope of utility model registration request] Heat resistant, made of polyimide resin glass laminate
An elastic insulating substrate, at least two conductive foils provided on the insulating substrate, an opening formed adjacent to the conductive foil, and a lead wire electrically connected to the conductive foil. A heat-sensitive element inserted into the opening, an external lead wire connected to the conductor foil, and a surface of the insulating substrate that is in contact with the heat generating surface of the rotating body, including the opening, are bonded. A temperature sensor characterized by being composed of a heat-resistant thin film sheet.