JP2528396Y2 - Temperature sensor - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a rotating member such as a heat fixing roller for fixing an unfixed toner image on a sheet used for a copying machine or the like on the sheet. Alternatively, the present invention relates to a temperature sensor for detecting a surface temperature of a stationary body.

[Conventional technology]

Conventionally, as a temperature sensor for detecting the surface temperature of the heat-fixing roller of the copying machine, for example, a contact-type temperature detecting device described in Japanese Patent Application Laid-Open No. Sho 56-1323 is known.

In this temperature detecting device, a thermosensitive element embedded in an elastic body is brought into contact with the surface of a heat fixing roller by pressing the surface of a heat fixing roller with the elasticity of the elastic body.

In this temperature detecting device, 0.5 to
Since a spherical bead type having a diameter of about 1.0 mm is used, when pressed against the heat fixing roller, the contact is close to a point contact, and there is a disadvantage that the surface of the heat fixing roller is easily damaged.

Also, due to the surface shape of the heat-sensitive element, the contact area with the heat-fixing roller is unstable, and there is a drawback that good thermal response characteristics cannot be obtained.

As a method for resolving such a drawback, for example,
A temperature detecting device described in Japanese Patent Application Laid-Open No. 56-1325 is disclosed.

This temperature detecting device has a metal foil interposed between the resin sheet and the elastic body of the above-described temperature detecting device, and collects heat from the heat fixing roller with the metal foil to increase the temperature detecting sensitivity. It is.

[Problems to be solved by the invention]

In this temperature detecting device, since the metal foil covers the entire surface of the heat-sensitive element and the elastic body, heat from the heat fixing roller escapes to the elastic body, and a sufficiently good thermal response characteristic cannot be obtained. There were drawbacks.

In addition, in manufacturing, not only the number of steps for covering the elastic body and the heat-sensitive element with the metal foil increases, but if the metal foil and the heat-sensitive element are not in close contact, the thermal response characteristics vary, and the yield decreases. Therefore, there was a drawback that its production was difficult.

[Object of the invention]

The present invention solves the above-described problems in the conventional temperature detection device as described above, and even when the temperature detection device is brought into contact with a rotating body such as a heat fixing roller, there is no risk of damaging the surface thereof, and the contact area is always constant. It is an object of the present invention to provide a temperature sensor which has no variation in thermal response characteristics while maintaining the above characteristics, and has excellent thermal response characteristics due to a heat collecting film.

[Means for solving the problem]

The present invention relates to a means for a temperature sensor for achieving the above-mentioned object, and relates to a heat-sensitive film in which a heat-sensitive film and an electrode are formed on one surface of an insulating substrate and a heat-collecting film such as a metal is formed on the other surface of the insulating substrate. An element, an elastic body having the heat collecting film surface of the thermal element facing the surface, and an elastic body attached so that the surface is flush, and a holder for holding the elastic body so that the thermal element faces the surface. The object is achieved by a thin insulating tape that covers at least the surface of the elastic body.

[Example of the invention]

Next, an embodiment of the present invention will be described with reference to the drawings. FIG. 1 and FIG. 2 show a thermosensitive element.

On one surface of an insulating substrate 1 made of alumina or the like, a heat-sensitive film 2 made of an oxide or the like is formed by means such as sputtering or screen printing, and an electrode 3 is further formed thereon. This is a terminal for extracting a change in resistance due to a change in temperature.

On the other surface of the insulating substrate 1, a heat collecting film 4, such as a metal film made of Al, Ni, Ag, Au, or an alloy thereof, or an infrared absorbing film such as gold black, is plated and patterned. , Vapor deposition, thick film printing, etc., and the data of the thermal response characteristic measurement data described later is an Al film.

In such a heat-sensitive element, a heat-sensitive film 2 and an electrode 3 are previously formed on one surface of a large insulating substrate 1 by a known semiconductor technique, and then a heat-collecting film 4 is formed on the other surface. It is cut by a sonic cutter or the like to form a chip as shown in FIG. 1, and a lead wire 5 is soldered to form a heat-sensitive element 6.

The heat-sensitive element 6 in the above embodiment has a size of 0.8 × 1.5 mm and a thickness of 0.25 mm, and it is desirable to form a protective film such as glass on the surface of the heat-sensitive film 2 as necessary.

FIGS. 3 and 4 show the heat-insulating elastic body 7 formed of a silicone rubber sponge, a silicone rubber sheet or the like.

The elastic body 7 shown in FIG.
And a notch groove 9 for burying the lead wire 5 of the thermal element 6 is formed.

When the heat collecting film 4 of the thermosensitive element 6 is embedded in the concave portion 8 of the elastic body 7 as an upper surface, the heat collecting film 4 and the surface of the elastic body 7 are flush with each other, and the rotational measurement target such as a heat fixing roller is used. There is no danger of damaging the surface.

The elastic member 7 shown in FIG. 4 is a concave portion 8 of the elastic member 7 shown in FIG.
Instead, a cut groove 10 is provided along the outer shape of the thermal element 6, and the cut groove 9 for inserting the lead wire 5 is provided in the same manner.

The portion surrounded by the cut groove 10 is an independent elastic body 7a
Then, the thermosensitive element 6 is placed on the thermosensitive element 6 and pushed into the elastic body 7 against the elasticity of the elastic portion 7a, and by using the elasticity, the force for pressing the thermosensitive element 6 against the object to be measured is increased. Is what you do.

As shown in FIGS. 5 and 6, the elastic body 7 thus fixed is fixed on a holding body 11, and the surface of the elastic body 7 including the thermal element 6 is covered with an insulating tape 12.

As the insulating tape 12, a film having a thickness of about 25 to 200 μm, such as polyimide or a fluororesin, is used from the viewpoint of abrasion resistance and thermal responsiveness.

In the case of FIG. 5, due to the tension of the insulating tape 12, the thermosensitive element 6 mounted on the elastic portion 7a is embedded in the elastic body 7 and contacts with the surface of the elastic body 7 in contact with the object to be measured. Become flush.

That is, since the elastic portion 7a moves independently with respect to the peripheral elastic body 7, the thermal element 6 is embedded with a small force, and no protrusion due to the thermal element 6 is generated on the surface of the insulating tape 12.

As the holding body 11, for example, an insulative substrate such as a printed circuit board on which a pattern can be formed is used, and a lead 15 of the thermosensitive element 6 and an external lead wire are formed on the pattern 15 formed thereon.
The external lead wire 14 is connected to the heat-sensitive film 2 by soldering the end of the wire 14.

The holding body 11 has engagement projections 11a formed on two opposing sides. The engagement projections 11a are attached to a holder in a fixing device of a copying machine, so that the temperature sensor is attached to the holder.

Further, on one side outside the two sides of the holding body 11, a projecting piece 11b for fixing the lead wire is formed, and along the external lead wire 14, a tube 16 is fitted together with the projecting piece 11b, and the external lead wire is connected. Fix it.

Generally, the thermal response characteristic of the temperature sensor is represented by overshoot temperature T _o and ripple temperature T _r as shown in Figure 7.

Higher overshoot temperatures T _o is small, the time to reach the set temperature becomes shorter, the control characteristics as the ripple temperature T _r is less is good.

When setting the surface temperature of the heat fixing roller of a copying machine 180 ° C., a temperature detector of JP 56-1325 JP described above, T _o = 18.5 ℃, was T _r = 6 to 7 ° C. .

In contrast, the in when not forming a Atsumarinetsumaku 4 in the heat-sensitive element 6 of Example, T _o = 12.5 ° C., while a T _r = 3 ° C., in embodiments of the present invention is, T _o = 8.5 ℃, T _r = 1
At 2 ° C., it can be seen that the thermal response characteristics have been greatly improved as compared with the prior art.

〔The invention's effect〕

As described above, the present invention relates to a heat-sensitive element having a heat-sensitive film and an electrode formed on one surface of an insulating substrate and a heat-collecting film formed on the other surface. Since it is buried so as to be flush, the thermal adaptability of the heat collecting film can significantly improve the thermal response characteristics.

In addition, since the surface of the elastic body and the surface of the heat collecting film of the heat-sensitive element are formed flush with each other, when the elastic body comes into contact with a rotating measurement surface such as a heat fixing roller of a copying machine, the rotation contact surface There is no danger of damage.

Also, in the manufacturing process, semiconductor manufacturing techniques such as sputtering, film thickness printing, and vapor deposition, which have been used in mass production, have been used in the manufacturing process, and can be manufactured in large quantities at low cost by cutting them. There are effects such as easy assembling process and improvement of working efficiency.

[Brief description of the drawings]

1 is a perspective view of the thermosensitive element of the present invention, FIG. 2 is a sectional view of the same figure, FIGS. 3 and 4 are perspective views of two embodiments of the elastic body, and FIG. 5 is an embodiment of the present invention. FIG. 6 is a cross-sectional view of the example, FIG. 6 is a perspective view of the same, and FIG. 7 is a general thermal response characteristic diagram. 1 ... insulating substrate, 2 ... heat-sensitive film, 3 ... electrodes, 4 ...
Heat collecting film, 6: thermosensitive element, 7: elastic body, 8: concave portion,
10 ... cut groove, 11 ... holding body.

Claims (1)

(57) [Scope of request for utility model registration] 1. A heat-sensitive element in which a heat-sensitive film and electrodes are formed on one surface of an insulating substrate and a heat-collecting film of metal or the like is formed on the other surface of the substrate, and a cut groove into which a lead wire of the heat-sensitive element is inserted. Is formed, and an elastic body having an elastic portion for mounting the thermal element in a concave portion where the thermal element is fitted or a portion having a different elasticity from the periphery thereof, and a surface of the elastic body and the concave portion or the elasticity A temperature sensor, comprising: an insulating tape coated so that a surface of the heat collecting film of the heat sensitive element placed on a different portion is flush with the heat collecting element; and a holder holding the elastic body. .