JPH0274836A - Temperature sensor - Google Patents

Abstract

PURPOSE:To prevent accumulation of toner between a heat roller and a temperature sensor by using a stainless steel sheet at the contact surface to the heat roller, and applying a fluororesin coat. CONSTITUTION:A temperature detecting element 1 which is formed in a thick film shape by using a thermistor material by screen printing and the like is held with a stainless steel attaching plate 5. The element 1 is fixed with a silicone based resin mold 7. A coating 8 comprising fluororesin such as Teflon is applied on a contact surface 5a of the attaching plate 5 with a heat roller 6. In this constitution, toner is not accumulated between the heat roller 6 and the attaching plate 5. As a result, the heat roller is not damaged, and the entire temperature sensor is not floated from the heat roller. Therefore, erroneous detection does not occur.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a temperature sensor used to detect the surface temperature of a rotating body, such as a toner constant-wearing heat roller of a copying machine.

BACKGROUND OF THE INVENTION In recent years, there has been remarkable progress in computer equipment that is indispensable to the information society, especially in terms of performance improvements and price reductions in copying machines.

This copying machine is equipped with a heat roller for keeping the toner constant, and a temperature sensor is used in order to control the surface temperature of the heat roller to about 180'C in contact with the heat roller. Recently, there has been a growing demand for improved performance and lower cost of this temperature sensor. The temperature sensor described here is
It was developed against this background.

The structure of a conventional temperature sensor will be explained with reference to FIG. FIG. 2 is a perspective view of a conventional temperature sensor. In Fig. 2, 1o is a bead-shaped thermistor element, 111L
, 11b are lead wires of 1° thermistor element, each with 12
It is connected to heat-resistant lead wires 1L and 12b. 1
3 is a silicon sponge, and the thermistor element 10 is fixed on the center surface thereof. Reference numeral 14 is an insulating plate made of phenol or bake, which fixes the silicone sponge 13 with adhesive and, at the same time, fixes the heat-resistant lead wires 121L and 12b. 16 is a polyimide film that wraps and holds the thermistor element 1o1, the silicone sponge 13, and the insulating plate 14. Reference numeral 16 denotes a stainless steel plate for attaching these temperature detection units to the fixing frame of the copying machine, and its spring properties allow it to be pressed against the surface of a heat roller or the like.

Problems to be Solved by the Invention However, in the conventional configuration described above, if toner remains on the copying machine side, that is, on the surface of the heat roller, the toner gets caught between the heat roller and the contact part of the temperature sensor and becomes a lump. , the surface of the heat roller 2 may be damaged, and the entire temperature sensor may be lifted off the heat roller.

Moreover, since polyimide film and silicone sponge have low thermal conductivity, the temperature sensor must be brought into contact with the heat roller with a relatively large pressure of about 100 f, which also causes scratches on the heat roller surface. . That is, there have been problems in that scratches may cause lines on the copied product or uneven shading. In addition, there was also a problem in manufacturing, which required a very labor-intensive process, such as wrapping and holding the temperature sensor in a polyimide film in order to make the contact part of the temperature sensor as smooth as possible.

The present invention solves the above-mentioned conventional problems. Even if toner adheres to the heat roller, the toner does not accumulate between the heat roller and the contact part of the temperature sensor, and does not damage the heat roller surface. Another object of the present invention is to provide a highly productive temperature sensor having an excellent structure that prevents the entire temperature sensor from floating off the heat roller.

Means for Solving the Problems To solve this problem, the temperature sensor of the present invention includes a temperature sensing element, a lead wire connected to an electrode of the temperature sensing element, and a mounting plate for holding the temperature sensing element. and a resin mold that protects the temperature sensing element and at the same time adhesively fixes the temperature sensing element to the mounting plate, and the mounting plate and the temperature sensing surface are integrated, and the temperature sensing surface is coated with fluororesin. It has a configuration that provides

Function: With this configuration, the contact surface to the heat roller is made of stainless steel and coated with Teflon, so even if toner is attached to the heat roller, toner will not accumulate between the contact portion of the heat roller and the temperature sensor. Therefore, it is possible to provide a temperature sensor having an excellent structure that does not cause any damage to the surface of the heat roller or cause temperature detection errors due to the entire temperature sensor being lifted off the heat roller.

Furthermore, according to the configuration of the present invention described above, from the viewpoint of mass production, there is no need for a very labor-intensive manufacturing process such as wrapping and holding the temperature sensor in a polyimide film in order to make the contact part of the temperature sensor as smooth as possible. You can get a significant effect on your skin.

EXAMPLE Hereinafter, an example of the present invention will be described with reference to the drawings.

FIG. 1a is a partially exploded perspective view of a temperature sensor according to an embodiment of the present invention, and FIG. 1a is a temperature sensing element thereof.

In the figure, 1 is constructed by screen printing a thermistor material on an insulating substrate with dimensions of approximately 3 mm (vertical) x approximately 4 mm (horizontal) x approximately 0.2 mm (thick) and whose main component is aluminum. It is a thick film temperature sensing element, and has electrodes 2&, 2b made of mu-Pt or the like. Electrode 2a.

Heat-resistant lead wires 4a and 4b are connected to 2b by high-temperature solders 32L and 3b, respectively. 5 is temperature sensing element 1
The temperature sensing element 1 is fixedly held by a silicone resin mold 7. For attachment, the contact portion Sa of the plate 6 with the heat roller 6 is coated with a coating 8 of fluororesin, such as Teflon (trade name).

The operation of the temperature sensor of this embodiment constructed in this manner will be described below. is used by bringing it into contact with the surface of the heat roller 6.

First, the temperature sensor is fixed to the mounting frame 9 so that the contact portion 62L of the temperature sensor smoothly contacts the rotating heat roller 6. Heat is transmitted from the heat roller 6 to the temperature sensing element 1 through the contact portion 6a. Since the temperature detection element 1 consists of a thermistor whose electrical resistance value changes depending on the temperature, the surface temperature of the heat roller 6 is controlled by measuring the electrical resistance value between the electrodes 2a and 2b via the lead wires 4a and 4b. can do.

As described above, according to this embodiment, by using stainless steel for the contact surface to the heat roller and applying a fluororesin coating, even if toner adheres to the heat roller, the contact portion between the heat roller and the temperature sensor is Provides a highly productive temperature sensor with an extremely superior structure that prevents toner from accumulating between the heat rollers, scratches on the heat roller surface, and the entire temperature sensor from floating off the heat roller. can do.

Effects of the Invention As described above, according to the present invention, a temperature sensing element, a lead wire connected to an electrode of the temperature sensing element, a mounting plate for holding the temperature sensing element, and a plate for protecting the temperature sensing element are provided. At the same time, the temperature sensing element is mounted with a resin mold that is adhesively fixed to the board, and the mounting is configured such that the board and the temperature sensing surface are integrated, and the temperature sensing surface is coated with fluororesin. Even if toner is attached to the heat roller, the toner will not accumulate between the contact area of the heat roller and the temperature sensor, causing damage to the heat roller surface, or causing the entire temperature sensor to float off the heat roller. It is possible to provide a temperature sensor with an excellent structure that does not cause temperature detection errors due to storage.

Furthermore, wrapping the temperature sensor in a polyimide film to make the contact area as smooth as possible eliminates the need for extremely laborious and difficult manufacturing processes, which is remarkable from the standpoint of mass production. A temperature sensor can be provided that can have an effect.

[Brief explanation of the drawing]

FIG. 1a is a partially exploded perspective view of a temperature sensor according to an embodiment of the present invention, FIG. 1 is a partially exploded perspective view of its temperature sensing element, and FIG. 2 is a perspective view of a conventional temperature sensor. 1...Temperature detection element, 21L, 2b...
...Electrode, xa, 4b...Lead wire, 5...
...Installation is by board, 7...Resin mold, 8.
...Fluororesin coating. Name of agent: Patent attorney Shigetaka Awano and one other person (C
1) /---! Entan Postal Code Otsu b 3b

Claims (1)

[Claims] a temperature sensing element, a lead wire connected to an electrode of the temperature sensing element, a mounting plate holding the temperature sensing element;
a resin mold that protects the temperature sensing element and at the same time adhesively fixes the temperature sensing element to the mounting plate, the mounting plate and the temperature sensing surface are integrated, and the temperature sensing surface is coated with fluororesin. A temperature sensor featuring: