JP2515114Y2 - Temperature sensor - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of application] The present invention relates to a temperature sensor for detecting the temperature of an object to be measured and, in particular, for fixing an unfixed toner image on paper, copying is performed. The present invention relates to a temperature sensor for detecting the temperature of an object to be measured such as a rotating heating fixing roller of a fixing device provided inside the machine and detecting the temperature thereof.

[Conventional technology]

A conventional temperature sensor of this type is disclosed in Japanese Patent Laid-Open No. 63-20553.
There is a temperature sensor described in JP-A-0.

This temperature sensor, as shown in FIG.
External drawer 2 that is held in 2 for connecting to the outside
A thermosensitive element 25 is arranged in the gap between a pair of strip-shaped metal plates 23, 24 having 3a, 24a, connected to the metal plates 23, 24.

A thin film sheet 26 is formed on one surface of the heat sensitive element 25 and the metal plates 23 and 24.
While being covered with, the metal plates 23, 24 are held by the holders 21, 22, and the thin film sheet 26 is brought into contact with an object to be measured such as a rotary heating fixing roller to measure the temperature of the object to be measured with the heat sensitive element 25. It was what was being measured.

[Problems to be Solved by the Invention]

In such a temperature sensor, the surface opposite to the surface in contact with the rotary heating fixing roller 40 is in an open state, and the thermal element
Since 25 is not firmly fixed to the surface of the thin film sheet 26, the heat sensing element 25 may not be able to accurately measure the heat of the rotary heating fixing roller 40 due to the floating of the thin film sheet 26, or the detection performance such as the detection speed is slow. It was inferior.

Further, in order to eliminate the above-mentioned drawbacks of such a temperature sensor, the heat sensitive element 25 and the lead wire connecting it to the metal plate may be fixed with a silicone rubber-based adhesive. Absorbs heat, which causes a drawback that the thermal response characteristics of the temperature sensor deteriorate.

The present invention solves the above-mentioned drawbacks of conventional temperature sensors of this type, and ensures that the heat-sensitive element is always in close contact with the thin film sheet so that it does not rise or move from the thin film sheet. It is an object of the present invention to provide a temperature sensor that is accurate and has a good thermal response characteristic by surely and quickly adding to the heat sensitive element.

[Means for solving the problem]

The present invention relates to means of a temperature sensor for achieving the above-mentioned object, comprising a pair of strip-shaped metal plates having an outer lead portion for connecting an outer lead wire, and a pair of metal plates for holding the pair of metal plates. A holder formed on at least one end of the metal plate, a heat-sensitive element disposed in a gap between the pair of metal plates and electrically connected to the pair of metal plates, and the heat-sensitive element and the metal plate. A thin film sheet that covers the upper surface of the sheet and contacts the object to be measured, a filler that surrounds the periphery of the heat sensitive element, and a cover sheet that seals and fixes at least the filler and the heat sensitive element between the thin film sheet. The purpose is achieved by and.

[Action]

In the temperature sensor of the present invention, the filler surrounding the heat sensitive element is sealed and fixed between the thin film sheet and the covering sheet for bringing the heat sensitive element and the pair of metal plates into contact with the object to be measured. The thermal element does not move away from or shift from the thin film sheet due to contact with the object to be measured or vibration.

By examining the material of the above-mentioned filling material with a small heat capacity, filling amount, etc., the thermosensitive element is always brought into close contact with the thin film sheet without deteriorating the thermal response characteristics of the thermosensitive element, and the temperature of the object to be measured is Is quickly transmitted to the heat-sensitive element, and an accurate temperature sensor having good thermal response characteristics can be obtained.

[Example of device]

Next, an example of implementation of the present invention will be described with reference to FIGS.

In FIG. 3, A is a lead frame formed by etching or the like using a metal plate made of Kovar, nickel, copper or the like. The lead frame A has a pair of strip-shaped portions 11 and 11 'on both sides. A pair of connecting portions 11a, 11 having a pair of extending portions extending perpendicularly from each of the strip portions 11, 11 '.
a ', a wide part 1,1' which is wider than the connecting parts 11a, 11a 'and is continuous with the connecting parts 11a, 11a', and semi-circular recesses 1a, 1a for accommodating the heat sensitive element 3. 'Is formed.

The recesses 1a, 1a 'are for narrowing the gap between the wide portions 1, 1', and are not always necessary if the gap is wide.

The wide portion 1, of the lead frame A formed in this way
At both ends of 1 ', a holding body 4 is resin-molded on one side and a holding body 5 is resin-molded on the other side by means such as transfer molding.
Screw holes 4a and 5a for mounting are also formed at the time of resin molding of 4,5.

Next, the heat sensitive element 3 such as a bead thermistor is attached to the recesses 1a, 1
The lead wire 3a is housed between a'and electrically connected to the wide portions 1, 1'by means such as welding.

Then, at least a portion of the wide portion 1, 1 ′ that contacts the rotary heating fixing roller 40 that is the object to be measured, that is, the wide portion 1, 1.
A thin film sheet 2 having abrasion resistance and heat resistance, such as a polyimide film, is attached to a part of the back surface of 1 '.

Further, as shown in FIG. 2, the heat sensitive element 3 is surrounded by a filler 6 such as silicon grease having a good heat conductivity and a small heat capacity, and the surface opposite to the thin film sheet 2 is covered with a cover sheet 7.
Then, the filler 6 and the thermosensitive element 3 are attached so as to seal and fix.

After that, the strip-shaped portions 11 and 11 'of the lead frame A are connected to the wide portion.
Cut from the end opposite to 1,1 'to obtain an individual temperature sensor C
As shown in FIG. 1, the strip-shaped portions 11,1 are obtained.
1'is used as a terminal for connecting an external lead wire.

As described above, when the holders 4 and 5 are collectively molded on the lead frame A by the transfer molding machine, not only the workability is remarkably improved as compared with the conventional molding and processing of individual products, but also the lead frame A Since the processing accuracy is high, the incidence of defective products due to dimensional variations can be reduced.

The molding of the holding bodies 4 and 5 is not limited to the transfer molding described above, and the holding bodies 4 and 5 which are resin-molded in advance are used.
It may be assembled on the lead frame A.

As shown in FIG. 4, the temperature sensor C thus formed has the thin film sheet 2 on which the thermosensitive element 3 is mounted.
, So that it is pressed against the surface of the rotary heating fixing roller 40,
The holders 4 and 5 are screwed to a fixing member in a fixing device of a copying machine (not shown).

In the temperature sensor C of the above-mentioned embodiment, the holders 4 and 5 are connected to the wide portion 1,
Although it is provided on both sides of 1 ', the present invention is not limited to the above, and at the end of the manufacturing process of FIG.
When cutting, the holder 4 is cut along the line D-D in FIG.
It is also possible to have a cantilever structure only.

Furthermore, a large number of holes are provided in the wide portion 1,1 'in a mesh shape,
While adjusting the elasticity of the wide part 11 ', the wide part 1,
It is also possible to reduce the heat capacity of 1 '.

Fig. 5 shows typical thermal response characteristics. The smaller the overshoot temperature T _{O in the} same figure, the shorter the time required to reach the set temperature, and the smaller the ripple temperature T _r , the better the control characteristics. Therefore, the thermal response characteristic can be expressed by the overshoot temperature T _O and the ripple temperature T _r .

The temperature sensor described in the above-mentioned JP-A-63-205530 is
Whereas _O = 8.8 ° C. and T _r = 2.9 ° C., the temperature sensor of the above-described embodiment has T _O = 5 ° C. and T _r = 2.9 ° C., showing a significant improvement in overshoot temperature. .

[Effect of device]

In the present invention, as described above, a heat-sensitive element is arranged in a gap between a pair of metal plates, the heat-sensitive element is electrically connected to the pair of metal plates, and the side on which the heat-sensitive element contacts the object to be measured. A pair of metal plates and the surface of the heat sensitive element, a thin film sheet is provided, and the heat sensitive element is surrounded by a filler such as silicon grease, and the surface opposite to the thin film sheet is sealed with a covering sheet,
It is fixed.

Therefore, by using a filler having excellent thermal conductivity, the heat of the object to be measured is absorbed from the entire surface of the heat-sensitive element through the filler, and the heat-sensitive surface is in surface contact. The response characteristics are remarkably excellent.

Further, in the metal plate, since the heat-sensitive element does not come into direct contact with this metal plate, even if the metal plate is thickened, heat does not escape from the heat-sensitive element, and its thermal response characteristics are not deteriorated.
The contact force to be brought into contact with the object to be measured can be adjusted by the thickness and elastic force of the metal plate, a temperature sensor suitable for the purpose of use can be obtained, and an appropriate contact force can be obtained. It can be a sensor.

Furthermore, since the surface of the temperature sensor opposite to the object to be measured is adiabatically covered with a cover sheet, heat from the surrounding airflow does not escape, and the effect on the heat-sensitive element can be reduced. Even then, the excellent thermal response characteristics become stable.

Moreover, not only is the metal plate used as an elastic body,
It can be used as a lead wire from a heat-sensitive element, and it can be integrally molded as a lead frame in the process of molding the holder, which can reduce the processing man-hours and assembly man-hours, and also prevent disconnection in the assembly process. And so on.

[Brief description of drawings]

1 to 4 show an embodiment of the present invention. FIG. 1 is a plan view, FIG. 2 is a sectional view taken along line BB of the same, FIG. 3 is a plan view of its manufacturing process, FIG. 4 is a side view of a state of use, FIG. 5 is a thermal response characteristic diagram, and FIG. 6 is a plan view of a conventional temperature sensor. A: Lead frame, C: Temperature sensor, 1,1 '...
Wide part, 11a, 11a '... Connection part, 2 ... Thin film sheet, 3
...... Heat sensitive element, 4,5 ...... Holder, 6 filler, 7 coating sheet.

Claims (1)

(57) [Scope of utility model registration request] 1. A pair of strip-shaped metal plates having an external lead-out portion for connecting an external lead wire, and a holder formed on at least one end of the pair of metal plates to hold the pair of metal plates. , A heat-sensitive element disposed in the gap between the pair of metal plates and electrically connected to the pair of metal plates, and covering one surface of the heat-sensitive element and the metal plate to contact an object to be measured. A temperature sensor comprising a thin film sheet, a filler surrounding the heat sensitive element, and a cover sheet for sealing and fixing at least the filler and the heat sensitive element between the thin film sheet.