JPS6222823Y2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a temperature sensor that measures the surface temperature of a rotating body, such as a heat fixing roller of an electrophotographic copying machine.

Since this type of temperature sensor is brought into sliding contact with the surface of a rotating body, errors may occur if the contact state is not constant. Also, do not damage the surface of the rotating body.

FIG. 1 shows a conventional temperature sensor for measuring the surface temperature of a heat fixing roller of an electrophotographic copying machine. The heat fixing roller 1 is heated by a heater 3, rolls into contact with a pressure roller 2, and is inserted between both rollers 1 and 2. Fixing is performed by applying heat and pressure to the copy paper. The surface temperature of the heat fixing roller 1 is detected by a heat sensitive element 5 such as a thermistor. The heat-sensitive element 5 is attached to the back surface of the metal plate 4, and the metal plate 4 is in sliding contact with the heat fixing roller 1.

The temperature sensor having the above configuration includes a metal plate 4
Since it comes into sliding contact with the heat fixing roller 1 which is a rotating body, it is difficult to make surface contact and it is impossible to obtain the above-mentioned constant contact state. In addition, metal plate 4
may damage the surface of the heat fixing roller 1. Furthermore, since the metal plate 4 easily radiates heat, it is affected by the environmental temperature.

FIG. 2 shows another example of a conventional temperature sensor. This temperature sensor has a heat-sensitive element 5 sealed in a glass tube 6.
is brought into sliding contact with the heat fixing roller 1.

This temperature sensor also has the same drawback as the one described above because the glass tube 6 is not in close contact with the heat fixing roller 1.

The present invention aims to eliminate the above-mentioned drawbacks, and FIGS. 3 and 4 show examples thereof.

The heat sensitive element 5 has a thickness of 50μ to 100μ, for example.
is attached to a flexible substrate 7 made of polyimide,
The output terminal is led out via a lead wire 8 printed on the flexible substrate 7. The flexible substrate 7 is attached to the support plate 9 through cushioning materials 10 and 11 made of sponge, with the attachment surface of the heat-sensitive element 5 facing inward. The cushioning material 11 covers the heat-sensitive element 5 on the flexible substrate 7, and the cushioning materials 10 are arranged on both sides thereof. The cushioning material 11 is softer than the cushioning material 10. As an example, for the former,
A sponge with a hardness of 5 to 10 is used, and a sponge with a hardness of 15 to 25 is used for the latter.

When a force F is applied to the support plate 9 in order to bring it into sliding contact with the heat fixing roller 1 so that the back side of the part of the flexible substrate 7 to which the heat-sensitive element 5 is pasted comes into contact with the heat-sensitive element 5, the flexible substrate 7 is heated. It curves along the surface of the fixing roller 1 and comes into close contact with it. Therefore, the heat sensitive element 5 faces the heat fixing roller 1 via the flexible substrate 7, receives heat from the heat sensitive element 5, and detects the temperature of the heat fixing roller 1.

By the way, when the material of the entire cushioning material is the same, when force F is applied to the support plate 9 in order to bring the flexible substrate into close contact with the heat roller, the pressure will be locally higher in the heat-sensitive element area than in the surrounding area. The flexible substrate and the heat-sensitive element on the surface of the heat roller were easily scratched, resulting in a very short lifespan for both.

There is also a method of making only the heat-sensitive element part hollow.
In this case, the surroundings other than the heat roller side of the heat-sensitive element are air, so the environment, such as the flow of wind due to convection,
The detected temperature varied depending on the ambient temperature, etc., and stable detected values could not be obtained.

The present invention includes a flexible substrate having a heat-sensitive element attached to the back surface, a first buffer material placed over the heat-sensitive element, and a portion adjacent to the heat-sensitive element bonded to the back surface of the flexible substrate. a second cushioning material;
It consists of a support member that supports the flexible substrate through both of the buffer materials, and since the first buffer material is softer than the second buffer material, no force is applied to the support plate 9. When F is applied, the pressure of the heat-sensitive element part of the flexible substrate against the heat roller does not locally become excessive pressure, and the flexible substrate is brought into close contact with the heat roller, so the flexible substrate The lifespan of both heat rollers and heat rollers can be extended due to abrasion.

[Brief explanation of the drawing]

FIGS. 1 and 2 are side views of conventional temperature sensors, respectively. FIG. 3 is a side view showing an embodiment of the present invention, and FIG. 4 is a front view of the flexible substrate. 1... Heat fixing roller, 5... Heat sensitive element, 7...
...Flexible substrate, 9... Support plate, 10... (Second
) buffering material, 11... (first) buffering material.

Claims (1)

[Scope of utility model registration request] a flexible substrate with a heat-sensitive element attached to its back surface; a first buffer material placed over the heat-sensitive element; and a second buffer material bonded to the back surface of the flexible substrate in a portion adjacent to the heat-sensitive element. and a support member that supports the flexible substrate via both the buffer materials, the first buffer material is softer than the second buffer material, and the first buffer material is softer than the second buffer material, and the first buffer material is softer than the second buffer material. A temperature sensor on the surface of a rotating body, characterized in that the flexible substrate has its surface pressed against the surface of the rotating body.