JPS6124906Y2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a temperature sensor that detects the temperature of a rotating body that rotates at a relatively low speed, such as a fixing heat roller inside a copying machine.

A conventional temperature sensor of this type had a configuration as shown in FIGS. 1 and 2. That is, a temperature-sensitive element 2 such as a thermistor is placed on a heat-sensitive plate 1 made of metal, and a protector 3 made of silicone rubber or the like is formed thereon. The conductive wire 2a of the temperature sensing element 2 is covered with an insulating tube 2b and led out to the outside. The heat-sensitive plate 1 of such a temperature sensor is pressed onto a rotating body (not shown) by utilizing its elasticity to detect the temperature on the surface of the rotating body.

However, since the heat-sensitive plate 1 is made of metal, the heat transfer is inaccurate and there is a temperature difference with the rotating body, making it impossible to accurately detect the temperature. Could not detect temperature. In addition, since the conducting wire 2a from the temperature-sensitive element 2 adhesively fixed to the heat-sensitive plate 1 is relatively thick like a composite wire, the elastic force of both the heat-sensitive plate 1 and the conducting wire 2a acts, and the elastic force may be affected depending on the method of fixing the conducting wire. There were variations in elastic force. As a result, errors may occur in the detected temperature depending on the method of fixing the conducting wire. Furthermore, if the elastic force is made too strong, the rotating body may be scratched because the heat-sensitive plate 1 is made of metal.

For this reason, a temperature sensor as shown in FIG. 3 was devised. That is, the temperature sensing element 2 is placed on one surface of an elastic body 4 such as silicone rubber, and is fixed together with the elastic body 4 to a holding body 6 with a thin film tape 5. This is a temperature sensor whose sensing surface is fitted due to the shape of the rotating body A, so that the heat radiation from the surroundings is small, and therefore the thermal time constant is relatively small.

However, in this temperature sensor, since it is necessary to make sufficient contact between the temperature sensing element 2 and the rotating body A, the temperature sensing element 2 is pressed against the rotating body A by means of a thin film tape 5 and an elastic body 4. There is a need. For this purpose, the temperature sensing element 2 is connected to the thin film tape 5.
, and a part of the thin film tape protrudes toward the rotating body A side. Therefore, when the surface of the rotary body A is coated with a coating layer of Teflon resin or the like, there is a drawback that contact marks of the protrusion of the temperature sensing element 2 are formed on the surface of the rotary body A as scratches.

The present invention has been developed in consideration of such a situation, and it is an object of the present invention to provide a temperature sensor that is free from the risk of breakage of the leet wire of the temperature sensing element or damage to the surface of the rotating body.

Examples of the present invention will be described below with reference to FIGS. 4 to 6.

Figures 4 and 5 show the sensor body used in the present invention, which is mounted on an insulating thin film sheet 9 (approximately 25μ to 200μ thick) made of resin such as vinyl chloride, polyester, polyethylene, polyimide, or fluorine resin. , a conductive foil 10 (about 35 μm thick) is formed by etching, adhesion, etc. Furthermore, an insulating thin film sheet 8 made of the same material as the insulating thin film sheet 9 is placed on top of the insulating thin film sheet 8.
(thickness approximately 25μ to 200μ) by adhesion, heat fusion, etc. This state is similar to that of a so-called flexible printed circuit board. Holes are formed at predetermined locations on this sheet 8 by a mechanical or chemical method, and the conductor foil 1
Expose part of 0. A temperature sensing element 7 such as a bead-shaped thermistor is inserted through this opening and placed on the sheet 9. Then, the conducting wire 7a of the temperature sensing element 7 is connected to the connecting portion 10a of the conductive foil 10 by soldering, welding, or the like.
Further, the end of the conductor foil 10 is connected to the output conductor lead-out portion 10b.
to be exposed as As a result of the above, the sensor body 11
is formed.

Figure 6 shows the state of use, and shows the sensor body 1
1 is bent into a U-shape, and both ends are inserted into the insertion hole 12a of the U-shaped holder 12, and an elastic body 13 such as silicone rubber is inserted between the holder 12 and the sensor body 11. intervene. Note that the sheet 9 of the sensor body 11 and the holder 12 are bonded together with an adhesive or the like. Further, an output conductor 14 is connected to the output conductor lead-out portion 11b of the sensor body 11. Further, it is preferable that the temperature sensing element 7 is fixed in contact with the sheet 9 using an adhesive such as silicone rubber.

The elastic body 13 also has a hollow cylindrical portion 13a formed on the side opposite to the surface on which the temperature sensing element 7 is placed.

Therefore, when pressed against the rotating body A, the elastic body 13
The pressing force is distributed over the entire contact surface and is not concentrated in the vicinity of the temperature sensing element 7, so that the rotating body A is not scratched.

These temperature sensors are pressed against the surface of the rotating body A, and the temperature change of the rotating body A is detected by the temperature sensing element 7. It is used to control the temperature of the rotating body A by increasing/decreasing the electric power of (1).

As described above, in the present invention, a conductor foil is interposed between thin insulating sheets, a part of the upper sheet is notched, a temperature sensing element is inserted into the notch, and the conductor of the temperature sensing element is connected to the conductor. Since the sensor connected to the exposed portion of the foil is attached to the holder via the elastic body, it has good adhesion to the object to be detected, and the temperature can be accurately detected with little heat radiation.
In addition, by forming a cavity on the side of the elastic body opposite to the surface on which the temperature-sensing element is placed, the contact area with the rotating body can be increased, and the pressure force is not concentrated near the temperature-sensing element. This has effects such as being able to prevent disconnection of the heating element, damage to the rotating body, etc., and reducing wear of the thin film sheet.

[Brief explanation of the drawing]

FIGS. 1 to 3 show conventional temperature sensors, and FIGS. 4 to 6 show an embodiment of the temperature sensor according to the present invention. FIG. 1 is a plan view, and FIG. 3 is a sectional view of another conventional example, FIG. 4 is a plan view of the sensor body, FIG. 5 is a sectional view taken along line A-A of the same, and FIG. 6 is a sectional view showing the state of use. be. 7... Temperature sensing element, 8, 9... Thin film sheet, 11
... Sensor body, 12 ... Holding body, 13 ... Elastic body, 13a ... Cavity part.

Claims (1)

[Scope of utility model registration request] A sensor in which a conductor foil with a predetermined pattern is formed between two insulating thin film sheets, a part of one of the sheets is cut out, a temperature sensing element is inserted, and the conductor of the temperature sensing element is connected to the conductor foil. a main body, a holder that faces the temperature sensing element side of the sensor main body and to which both ends of the sheet are fixed, and a holder interposed between the holder and the sheet of the sensor main body, and the holder 1. A temperature sensor comprising an elastic body such as silicone rubber with a cavity formed on the surface in contact with the temperature sensor.