JPH088433Y2 - Temperature detector - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial field of application) The present invention relates to a temperature detector used for controlling the surface temperature of a heating body such as a fixing roll of a copying machine or a laser printer.

(Prior Art) In recent years, a temperature detector called STS (soft touch sensor) has been widely used for surface temperature control of a heating body such as a fixing roll of a copying machine or a laser printer.

A temperature detector of this type is described in detail in Japanese Utility Model Publication No. 57-19612, entitled "Temperature Detector", but its construction will be briefly described.

FIG. 3, FIG. 4 (a) and FIG. 5 (a) are perspective views showing an example of a conventional temperature detector.

In FIG. 3, a sponge 2 made of a heat-resistant material such as silicone rubber is placed on an insulating substrate 1 made of epoxy resin mixed with glass, and a temperature detecting element 9 such as a thermistor or thermocouple is placed on the surface thereof. To be done. Further, the temperature detecting element 9 includes a temperature detecting element portion 10 and lead wire portions 4, 4
Consists of. The substrate, sponge, and temperature detecting element are covered with an adhesive film 7 made of polyimide or the like having excellent heat resistance and insulation. Here, the insulating substrate 1 is used when relaying the lead wire portions 4 and 4 and the coated lead wires 8 and or when it is attached to a metal fitting as a temperature detector.

Further, as shown in FIGS. 4 (a) and 4 (b), a heat collecting plate 6 made of aluminum foil may be arranged on the temperature detecting element 9 , or as shown in FIGS. 5 (a) and 5 (b). It is well known to dispose the heat collecting plate 6 made of aluminum foil under the temperature detecting element 9 .

(Problems to be Solved by the Invention) Among the conventional temperature detectors described above, those provided with a heat collecting plate as shown in FIGS. 4 and 5 are heat collecting devices as shown in FIG. Although the response time is significantly improved compared to the one without a plate, uniform heat collection is performed because only the element part (convex part) of the temperature sensing element contacts the surface (heat source) of the temperature-measuring body. However, there is a drawback in that the response time varies.

An object of the present invention is to eliminate such drawbacks and to provide a temperature detector which has a uniform response time, a quick response time, and no variation.

(Means for Solving the Problems) In order to achieve the above object, a temperature detector according to the present invention comprises a thermistor including a thermistor element part and a thermistor lead wire part, and a sponge-like elastic body for supporting the thermistor. In a temperature detector consisting of a heat-resistant insulating film having a small friction coefficient that wraps around and smoothly contacts the temperature-measured body, between the thermistor and the heat-resistant insulating film,
The thermistor element portion is provided with a heat collecting plate in a state of being in contact with only the thermistor lead wire portion without covering the thermistor element portion, and both the thermistor element portion and the thermistor lead wire portion are thermally coupled to the temperature-measuring object. It is characterized by that.

(Function) Since the temperature detector according to the present invention has a structure in which the heat collecting plate is not arranged on the element part of the thermistor, but the heat collecting plate is arranged in contact only with the lead wire part of the thermistor, the temperature detector surface Thus, not only the element portion of the thermistor but also the lead wire portion of the thermistor can be thermally coupled (thermally contacted) well with the surface of the temperature-measured body such as the fixing roll. Therefore, the temperature (heat) of the temperature-measured body can be uniformly collected from both the element portion of the thermistor and the lead wire portion of the thermistor, and the variation in response time is remarkably improved.

Embodiment Hereinafter, the present invention will be described in more detail with reference to the drawings.

FIG. 1 (a) is a perspective view showing an embodiment of the temperature detector according to the present invention, and FIG. 1 (b) is a side view thereof.

 FIG. 2 is a perspective view showing another embodiment.

1 (a) and 1 (b), a cubic silicone rubber sponge 2 having a side of 10 mm is arranged on an insulating substrate 1 made of epoxy resin mixed with glass, and the surface of the sponge 2 is Thermistor element part 3 and lead wire parts 4, 4
A thermistor 5 consisting of Where the lead wire part
4 and 4 are covered with a polyimide tube to maintain insulation.

Next, a heat collecting plate 6 made of a ring-shaped aluminum foil having a thickness of 50 μm is arranged on the lead wire portions 4, 4. Then, each part is fixed by being covered with an adhesive film 7 made of polyimide, which is slippery and excellent in heat resistance and insulation, all around, and is used as a temperature detector. The lead wire portions 4, 4 are penetrated into the back surface of the insulating substrate 1 and are connected to the print pattern on the back surface by soldering or the like, and at the same time, are connected with the coated lead wires 8, 8.

In order to investigate the response time of the temperature detector, a hot plate precisely controlled to 50 ° C and 150 ° C is prepared for each of the temperature detector according to the present invention and the conventional temperature detector shown in FIG. Then, the response time between the temperatures was measured.

When the measurement result is represented by the average value of the thermal time constant (time until 63.2% of 100% response is reached) τ and the standard deviation S, the conventional example has = 2.0 sec and S = 0.77 sec. On the other hand, in the case of this example, = 2.1 sec and S = 0.23 sec.

In this way, the one of this embodiment is
Remove the aluminum foil on the thermistor element part 3 and remove the lead wire part.
By providing aluminum foil only on 4 and 4, the height of the thermistor element part 3 is supplemented with aluminum foil, so the unevenness of the surface is significantly improved, the heat collection from the heat source is good, and the response time is the same. Moreover, the standard deviation can be reduced to 1/3 or less.

In this example, the lead wire was covered with a polyimide tube and a ring-shaped aluminum foil was used as the heat collecting plate.
As shown in the figure, the lead wires 4 and 4 are not covered with a tube, and the heat collecting plate 6 is divided and arranged as shown in the figure.
It is also possible to directly transfer the heat of the heat collecting plate to the lead wire portion and shorten the response time.

Further, although the thermistor is used as the temperature detecting element in the present embodiment, the same effect can be obtained by using a thermocouple or the like.

(Effect of the Invention) As described above, according to the present invention, the heat collecting plate is not arranged in the element portion of the thermistor, and the heat collecting plate is arranged in contact only with the lead wire portion of the thermistor. The unevenness of the surface of the temperature detector is reduced, so that not only the element portion of the thermistor but also the lead wire portion of the thermistor is well thermally coupled (thermally contacted) with the surface of the temperature-measured body such as the fixing roll. Therefore, it becomes possible to collect the temperature (heat) of the object to be measured uniformly from both the thermistor element part and the thermistor lead wire part, and accurate temperature detection with significantly improved variation in response time. It is possible to provide a temperature detector capable of

[Brief description of drawings]

FIG. 1 (a) is a perspective view showing an embodiment of the present invention, and FIG. 1 (b) is a side view thereof. FIG. 2 is a perspective view showing another embodiment of the present invention. FIG. 3, FIG. 4 (a) and FIG. 5 (a) are perspective views showing an example of a conventional temperature detector, and FIG. 4 (b) and FIG. 5 (b) are respectively 4 (a) and 5 (a)
FIG. 1 ... Insulating substrate 2 ... Sponge 3 ... Thermistor element part 4 ... Lead wire part 5 ... Thermistor 6 ... Heat collecting plate 7 ... Adhesive film 8 ... Coated lead wire 9 ... Temperature sensing element 10 ...... Temperature sensing element section

Claims (1)

[Scope of utility model registration request] 1. A thermistor comprising a thermistor element portion and a thermistor lead wire portion, a sponge-like elastic body for supporting the thermistor, and a heat-resistant insulating film having a small friction coefficient which covers the thermistor and smoothly contacts the temperature-measuring body. In the temperature detector consisting of, between the thermistor and the heat-resistant insulating film, a heat collecting plate is provided in a state of contacting only the thermistor lead wire portion without covering the thermistor element portion, and the thermistor element portion and the thermistor lead wire are provided. A temperature detector characterized in that both of the parts are thermally coupled to the temperature measurement target.