JPH067190U - Heating element - Google Patents

Abstract

(57) [Abstract] [Purpose] A plurality of positive temperature coefficient thermistor elements that can improve the adhesion to a heated object and efficiently heat the heated object with a desired temperature distribution such as uniform are used. Get a heating element. [Structure] Case 13 having an opening formed on one surface side
, A plurality of PTC elements 12 are arranged, the lower electrode of the PTC element 12 is electrically connected to the spring portion 14a of the spring terminal plate 14, and the upper electrode of the PTC element 12 is electrically connected to the flat terminal plate 15. The insulating member 17 on the flat terminal plate 15.
To provide. The insulating member 17 is provided so as to be movable toward the object 16 to be heated, and the insulating member 17 is pressed against the object 16 to be heated by the pressing force of the spring portion 14a.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a heating element provided with a plurality of thermistor elements having a positive temperature characteristic (PTC). For example, a heating element that can be used as a long heater that can be used for toner fixing of a printer or the like. It is about the body.

[0002]

[Prior art]

 PTC thermistors are often used as heating elements having a self-temperature control function. As a heating element of such a PTC thermistor, a heating element made of an organic material and a heating element made of a ceramic material are known. Recently, applications for heating a long object to be heated have come out, and a long heating element for heating such a long object is required.

Since the heating element made of an organic material has flexibility, it can be easily processed into a long shape, but there is a problem in its resistance temperature characteristic, and a sufficiently stable heating element at a high temperature cannot be obtained. FIG. 2 shows resistance-temperature characteristics of a heating element made of such an organic material. As shown in FIG. 2, the PTC heating element made of an organic material has a gradual resistance change curve with respect to temperature, and the self-temperature control function is insufficient. Therefore, it was difficult to obtain the required temperature accuracy.

FIG. 2 also shows the resistance temperature characteristic of the ceramic PTC heating element. As shown in FIG. 2, since the ceramic PTC heating element exhibits a steep resistance change with respect to temperature, the heating temperature control accuracy of the heating element itself is extremely good. However, the ceramic PTC is poor in flexibility, and in order to form a long heater, it is necessary to arrange a plurality of ceramic PTC elements side by side.

[0005]

[Problems to be solved by the device]

 FIG. 3 is a side view showing a long heater formed by arranging a plurality of PTC elements in a straight line and electrically connecting them in parallel. With reference to FIG. 3, the elongated heater 1 is configured by disposing a plurality of PTC elements 2 in a case 3. A spring terminal plate 4 is provided below the PTC element 2, and a flat terminal plate 5 is provided above the PTC element 2. The lower electrode of the PTC element 2 is electrically connected to the spring portion of the spring terminal plate 4. The upper electrode of the PTC element is electrically connected to the flat terminal plate 5. Each PTC element 2 is sandwiched between the flat terminal plate 5 and the spring portion of the spring terminal plate 4 in the case 3 by the pressing force of the spring portion of the spring terminal plate 4. When heating using this long heater 1, as shown in FIG. 3, the upper part of the long heater 1 is brought into contact with the object 6 to be heated. The heat generated in each PTC element 2 is transmitted to the object to be heated through the flat terminal plate 5 and the upper plate of the case 3, and the object to be heated 6 is heated.

As described above, since the object to be heated is heated by the heat transfer due to the contact, if the object to be heated or the heater has a warp or a distortion, it is shown in FIG. 3 between the heater and the object to be heated. Such a gap 7 is generated, which causes a problem that heating cannot be performed efficiently. Also, when heating is performed uniformly with a long heater or when heating is performed so as to obtain a desired temperature distribution, the desired temperature is obtained due to good heat conduction in the contacting part, but Heat conduction is poor in the portion where the heat generation occurs, and it cannot be heated to a desired temperature. Therefore, there is a problem that heating cannot be performed uniformly or with a desired temperature distribution.

The object of the present invention is to improve the adhesion to the object to be heated, which enables efficient heating and heating in a uniform or desired temperature distribution state. It is to provide a heating element that can.

[0008]

[Means for Solving the Problems]

 The heating element of the present invention is provided with a case member having an opening formed on one side thereof, a plurality of positive temperature coefficient thermistor elements arranged in the case member, and an opening of the case member. An insulating member provided in the case member so as to be movable toward the object to be heated and in contact with the object to be heated, and one electrode of each positive temperature coefficient thermistor element provided between the insulating member and the positive temperature coefficient thermistor element. And a first terminal plate electrically connected to the other electrode of each PTC thermistor element, and each PTC thermistor element is moved toward the opening to move the insulating member to the heated object. And a second terminal plate having a spring portion that individually presses each of the positive temperature coefficient thermistor elements so that they are brought into contact with each other.

[0009]

[Action]

 In the heating element of the present invention, an opening is formed in the case member, and the insulating member provided so as to close the opening is provided so as to be movable in the case member toward the heated object. There is. In the present invention, the second terminal plate electrically connected to the other electrode of the PTC thermistor element has a spring portion, and the spring portion individually presses each thermistor element. By the pressing of the spring portion, a force acts to move each PTC thermistor element in the direction of the opening, whereby the insulating member is pressed against the object to be heated, and the insulating member and the object to be heated come into contact with each other. Since such a force acts on each PTC thermistor element individually, the insulating member is pressed toward the heated object and deforms in the part where a gap is created between the heated object and the heated object. It comes into contact with the body.

Therefore, even if there is a warp or a distortion in the heated body or a contact portion of the heated body with the heated body, the insulating member is deformed so as to follow the warped or the distortion. And the insulating member come into close contact with each other.

[0011]

【Example】

 FIG. 1 is a cross-sectional view showing an embodiment according to the present invention. Further, FIG. 4 is a vertical cross-sectional view taken along the line AA of FIG. 1 showing a state in which the long heater 11 of this embodiment is mounted on the object to be heated 16. Referring to FIGS. 1 and 4, a plurality of PTC elements 12 are provided in case 13. An opening is formed above the case 13, and an insulating substrate 17 is provided in the opening of the case 13 so as to close the opening. A spring terminal plate 14 is provided between each PTC element 12 and the bottom of the case 13. The PTC element 12 is pressed upward by the spring portion 14a of the spring terminal plate 14. The lower electrode of the PTC element 12 is electrically connected to the spring portion 14a.

A flat terminal plate 15 is provided between each PTC element 12 and the insulating substrate 17. The upper electrode of each PTC element 12 is electrically connected to this flat terminal plate 15. The insulating substrate 17 is placed on the flat terminal plate 15, and when each PTC element 12 moves in the vertical direction, the insulating substrate 17 also moves in the vertical direction accordingly. It is provided.

Referring to FIG. 1, when case 13 is pressed upward and attached to body 16 to be heated, upper ends 13 a and 13 b of case 13 come into contact with body 16 to be heated. In this state, each PTC element 12 is pressed upward by the spring portion 14a of the spring terminal plate 14, and therefore, in the portion where a gap is formed between the PTC element 12 and the heated body 16, the spring portion is absent. The PTC element 12 is pressed upward by the pressing force of 14a. As a result, the flat terminal plate 15 and the insulating substrate 17 thereon are pressed against the object to be heated 16 and are brought into close contact with the object to be heated 16. The flat terminal plate 15 and the insulating substrate 17 need to have a certain degree of flexibility so that they can easily come into contact with the object to be heated 16. As such a flexible insulating member, a porcelain plate, an insulating film, or the like can be used. In the embodiment shown in FIGS. 1 and 4, a porcelain plate is used.

As a result, as shown in FIG. 4, the insulating member 17 is pressed upward in the portion where a gap is formed between the heating target 16 and the heating target 16 and is brought into close contact with the heating target 16. Therefore, the entire heater comes into close contact with the object to be heated, and heat is efficiently conducted at all points. Therefore, the object to be heated can be heated with a desired temperature distribution.

FIG. 5 is a cross-sectional view showing another embodiment according to the present invention. In this embodiment, grooves 13c 1 and 13d 3 are formed at the tips 13a and 13b of the case 13 along the longitudinal direction of the case. Both ends of the insulating member 17 are fitted in the grooves 13c and 13d. Therefore, the insulating member 17 is provided so as to be vertically movable within the range from the lower end to the upper end of the grooves 13c and 13d. The heater of this embodiment is used to heat the body 16 to be heated having the convex portion 16a as shown in FIG. The case 13 is set at a position where the convex portion 16a of the body to be heated 16 corresponds to the insulating member 17, and the case 13 is pushed upward to attach the elongated heater 11.

FIG. 6 is a cross-sectional view showing the state of attachment in this way. As shown in FIG. 6, the convex portion 16 a of the body to be heated 16 contacts with the insulating member 17 and the insulating member 17 is pressed downward. The insulating member 17 has the flat terminal plate 15 and the PTC element 12 interposed therebetween. Since it is pressed upward by the spring portion 14a of the spring terminal plate, the convex portion 16a and the insulating member 17 are in close contact with each other. Therefore, even if the convex portion 16a of the object to be heated has a warp or distortion, the insulating member 17 adheres closely to the warp or the distortion to efficiently conduct heat, and the object to be heated 16 has a desired temperature distribution. It is possible to heat the convex portion 16a.

FIG. 7 is a cross-sectional view showing another embodiment according to the present invention. In this embodiment, the insulating film 18 is used as the insulating member that contacts the object to be heated. With reference to FIG. 7, the insulating film 18 covers not only the upper portion of the flat terminal plate 15 but also the entire periphery of the elongated heater 11. Since such an insulating film 18 covers the heater, a film having high heat resistance such as polyimide is preferable. Also in this embodiment, since the insulating film 18 is pressed upward by the spring portion 14a of the spring terminal plate via the flat terminal plate 15 and the PTC element 12, the long heater 11 is not heated. When attached to the body 16, it adheres well to the body 16 to be heated, and the heat from the PTC element 12 is transferred to the body 16 to be heated through the flat terminal plate 15 and the insulating film 18. Since no gap is formed between the insulating film 18 and the heated body 16, heat can be efficiently transmitted and the heated body 16 can be heated with a desired temperature distribution.

[0018]

[Effect of device]

 According to the present invention, the positive temperature coefficient thermistor element provided in the case member is provided so as to be individually moved in the direction of the opening by the spring portion of the second end plate. An insulating member, which is provided to close the opening of the case member against the pressing force of the spring portion, is provided so as to be movable in the case member toward the object to be heated. Contact with heating element. The pressing force exerted by the spring portion acts on each PTC thermistor element individually. Therefore, even if there is warpage or distortion on the surface of the object to be heated, the insulating member does not act at the portion where the pressing force of the spring portion acts individually and a gap is created between the object to be heated and the insulating member. The insulating member comes into contact with the object to be heated when pressed against the object to be heated. Therefore, according to the present invention, the adhesion of the insulating member to the object to be heated can be improved, and the heat can be efficiently transferred to the object to be heated in all parts of the heating element. The body can be heated with a desired temperature distribution, such as uniform.

Since the force of pressing the insulating member against the object to be heated is due to the spring portion of the second terminal plate, the insulating member should be pressed against the object to be heated with substantially the same force in each part of the heating element. You can

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing a first embodiment according to the present invention.

[Fig. 2] Ceramic PTC heating element and P made of organic material
The figure which shows the resistance temperature characteristic of TC heating element.

FIG. 3 is a side view showing a comparative heating element in which a plurality of positive temperature coefficient thermistor elements are arranged in a case member.

FIG. 4 is a vertical cross-sectional view taken along the line AA of FIG. 1 showing a state in which the first embodiment according to the present invention is attached to a body to be heated.

FIG. 5 is a cross-sectional view showing a second embodiment according to the present invention.

FIG. 6 is a cross-sectional view showing a state in which the second embodiment shown in FIG. 5 is attached to a body to be heated.

FIG. 7 is a cross-sectional view showing a third embodiment according to the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 11 ... Long heater 12 ... PTC element 13 ... Case 13a, 13b ... Tip part 13c, 13d ... Groove part of case opening 14 ... Spring terminal plate 14a ... Spring part of spring terminal plate 15 ... Flat terminal plate 16 ... Heated object 16a ... Convex portion of heated object 17 ... Insulating member 18 ... Insulating film as insulating member

Claims (1)

[Scope of utility model registration request] 1. A case member having an opening formed on one side, a plurality of positive temperature coefficient thermistor elements arranged in the case member, and a case member provided so as to close the opening of the case member. An insulating member that is movable in the case member toward the heated body and is in contact with the heated body, and is provided between the insulating member and the positive temperature coefficient thermistor element, and one of the positive temperature coefficient thermistor elements is provided. A first terminal plate electrically connected to the electrode and the other electrode of each PTC thermistor element are electrically connected, and each PTC thermistor element is moved toward the opening to heat the insulating member. And a second terminal plate having a spring portion that individually presses each PTC thermistor element so as to contact the body.