JP2002156292A - Temperature sensor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve thermal response of a surface contact type temperature sensor using a thermistor element. SOLUTION: A disclosed temperature sensor has a cushion member piece 22 on a support stage 13 upper surface. To the sensor part where the thermistor element 23 is fixed by way of a heat conductor thin film 54, the ends of heat resistant sheets 61 and 62 whose shorter one is overlapped inside and contacted are fixed to the lower surface of the support stage. Covering and rolling the cushion member piece and the thermistor element, the roll end is fixed to the lower surface of the support stage. Seamed lines 66 and 67 of the start of roll of the heat resistant sheet coincide with one corner of the support stage lower surface and the seamed line 68 of the end of roll coincide with the other corner of the support stage lower surface. The inner heat resistive sheet covers the thermistor element and the thermal conductor, and a protection film whose end of roll does not reach the seamed line 68 is provided. The direction of the roll is maintained perpendicular to the rotation axis of the rotor.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a temperature sensor using a thermistor, and more particularly to a temperature sensor for detecting a surface temperature, which is suitable for contacting the surface of a rotating body to measure the temperature.

[0002]

2. Description of the Related Art For example, in a copying machine or the like, an electrostatic latent image of a character or an image is formed on the surface of a sheet by optical means, and then developed by attaching toner to the sheet. Is heated by a high-temperature fixing heat roller to fuse the toner, thereby fixing characters and images. At this time, in order to perform the fixing operation correctly, the surface temperature of the heat roller for fixing must be controlled so as to be constantly maintained at a constant temperature determined by the properties of the toner. It is necessary that the surface temperature of the fixing heat roller can be accurately measured during rotation. Furthermore, in order to enable a high-speed copying operation, the rotation speed of the fixing heat roller tends to increase, and therefore, the temperature sensor used for such a purpose is used during the rotation of the fixing heat roller. It is required to constantly and reliably contact the surface of a high-temperature fixing heat roller so that the surface temperature can be measured and the responsiveness to a temperature change is improved.

FIG. 10 shows an example of the structure of a temperature sensor conventionally used for measuring the surface temperature of a rotating body. FIG. 10A is a top view of the temperature sensor, and FIG. FIG. In this conventional example, a leaf spring 100 made of a thin metal plate having elasticity such as stainless steel or phosphor bronze is used.
Is fixed to one end of the resin molded body 101 by embedding one end thereof, and bonding a cushion material piece 102 made of a heat-resistant soft resin foam material to one surface of the other end. The structure has a thermistor element 104 attached to the upper surface of the cushion material piece 102 via a metal foil 103. Two terminal plates 105 and 106 are independently embedded in the other end of the resin molded body 101, and two lead wires 107 and 108 of the thermistor element.
Are grooves 109, 1 provided on the upper surface of the resin molded body 101.
Through 10, they are connected to terminal plates 105 and 106, respectively. At this time, an insulating sheet 111 is attached to the upper surface of the leaf spring 100 in advance, and the lead wires 107 and 1 are attached.
08 is insulated from the leaf spring 100 by the insulating sheet 111. Further, a heat-resistant sheet including the cushion material piece 102 and the thermistor element 104 is folded from the lower side to the upper side and wound around the distal end of the leaf spring 100 to form a protective film portion 112, thereby forming a thermistor. The element 104 is insulated and mechanically protected. Further, the terminal plate 10
5 and 106, the external lead wires 113 and 114 are processed by removing the coating.
As shown by marks, they are fixedly connected by a method such as spot welding or the like, and the distal end portions of the terminal plate and the external lead wires are covered with insulating tubes 115 and 116 so as to provide electrical insulation and mechanical protection. It has become.

The temperature sensor shown in FIG. 10 is fixed to a part of a casing of a copying machine (not shown) using a mounting hole 117. At this time, the thermistor element 104 attaches the protective film section 112 to the protective film section 112. As a result, the resistance value of the thermistor element 104 changes in accordance with the surface temperature of the fixing heat roller by contacting the surface of the fixing heat roller (not shown). By detecting, the surface temperature of the fixing heat roller can be measured. At this time, the cushion material piece 102 keeps the mechanical followability when the thermistor element portion is brought into contact with the surface of the fixing heat roller, and prevents the temperature sensor from being displaced from the housing of the copying machine. The effect of alleviating the characteristic change based on this is obtained. The metal foil 103 performs a heat collecting action on the thermistor element 104 from the surface of the fixing heat roller to improve thermal responsiveness. In addition, the protective film portion 112 functions to prevent wear of the thermistor element 104 due to rotation of the fixing heat roller and to provide insulation and pressure resistance to a high voltage between the fixing heat roller. ing.

FIGS. 11A and 11B show another example of a conventional temperature sensor, wherein FIG. 11A is a top view and FIG.
Shows a side view. In this conventional example, two temperature sensors are connected to a common base 40 made of a metal plate having a spring property.
0, the heat-resistant resin molded body 20
0, 300, a support 201 protruding from one end
Cushion pieces 202 and 302 made of a heat-resistant soft resin foam material are adhered to the upper surface of
02 and 302 via metal foils 203 and 303,
It has a structure to which thermistor elements 204 and 304 are attached. Two terminal plates 205, 206 and 30 are provided at the ends of the heat-resistant resin molded bodies 200 and 300 in the orthogonal direction, respectively.
5 and 306 are embedded independently, and two lead wires 207, 208 and 307 of the thermistor element,
308 is connected to terminal plates 205, 206 and 305, 306 via grooves 209, 210 and 309, 310 provided on the upper surfaces of the resin molded bodies 201, 301, respectively.

At this time, with respect to the support tables 201 and 301,
Cushion material pieces 202 and 302 and thermistor element 20
By attaching a heat-resistant sheet so as to surround the thermistor elements 204 and 304, the thermistor elements 204 and 304 are electrically insulated and mechanically protected. ing. Further, to the terminal plates 205, 206, 305, and 306, the external lead wires 212, 213, 312, and 313 are fixed to the respective distal ends, which have been subjected to processing such as removing the coating, by a method such as spot welding. The terminal tube and the distal end of the external lead wire are connected to an insulating tube 21.
4, 215 and 314, 315 are provided to provide electrical insulation and mechanical protection. The terminal plates 205 and 206 are provided on the terminal plate side of the heat-resistant resin molded products 200 and 300, respectively.
And 305, 306, the two legs 401, 402 of the base 400 are embedded,
The two temperature sensors are integrated with the base 400. The base 400 is provided with mounting holes 403 and 404.

The temperature sensor shown in FIG.
03, 404, it is fixed to a part of the housing of a copying machine (not shown).
The resistance value of the thermistor elements 204 and 304 changes according to the surface temperature of the fixing heat roller by contacting the surface of the fixing heat roller with the surface of the fixing heat roller (not shown) via the protective film portions 211 and 311. Therefore, the surface temperature of the fixing heat roller can be independently measured by detecting a change in each resistance value by a measurement circuit (not shown). At this time, the cushion members 202 and 302 and the base portion 400 maintain the mechanical followability when the thermistor element portion is brought into contact with the surface of the fixing heat roller, based on the elasticity thereof, and copy. The effect of reducing a characteristic change due to a shift of the mounting position of the temperature sensor with respect to the machine housing or the like is provided. The metal foils 203 and 303 perform a heat collecting action on the thermistor elements 204 and 304 from the surface of the fixing heat roller to improve thermal responsiveness. In addition, the protective film portions 211 and 311 prevent the thermistor elements 204 and 304 from being worn due to the rotation of the fixing heat roller, and have an electrical insulation property and a pressure resistance against a high voltage between the fixing heat roller. And the action of imparting

In the conventional temperature sensor shown in FIG. 11, the surface temperature of the fixing heat roller is measured independently by using two thermistor elements. It is used for temperature control to keep the roller surface temperature constant at all times, and the other temperature sensor shuts off the heating power supply when the surface temperature of the fixing heat roller rises to a predetermined temperature or higher. Used for safety measures, such as preventing the occurrence of a condition.

FIGS. 12A and 12B show another example of the structure of the lead wire connecting portion in the temperature sensor. FIG. 12A is a top view and FIG. 12B is a sectional view taken along the line XX. Is shown. In this conventional example, for example, in the case of the temperature sensor shown in FIG. 10, a terminal accommodating portion 500 surrounding each terminal plate is protruded from the terminal plate side of the resin molded body 101, and is integrally molded. It is provided. Terminal housing 50
Reference numeral 0 denotes a gutter shape having an open upper surface, in which a terminal plate 501 is housed, and an opening 502 for passing an external lead wire 503 including a coating portion is provided at an end. I have. When connecting the external lead wire, the end portion of the external lead wire 503 is passed through the opening 502, and the portion which has been subjected to processing such as removing the coating on the end portion is connected to the terminal plate 5.
01, for example, to provide a soldering portion 504,
Alternatively, they are fixedly connected by a method such as resistance welding. Thereafter, the tip of the lead wire 503 is fixed in the terminal accommodating section 500 by injecting the adhesive 505 into the gutter-shaped section of the terminal accommodating section 500.

[0010]

However, FIG.
Or, in the conventional temperature sensor shown in FIG. 11, the adhesion between the protective film portion and the fixing heat roller is poor,
Since the surface shape of the heat-resistant sheet forming the protective film portion may be uneven and may not be smooth, due to the influence, the thermal responsiveness may be reduced or unstable, or the partner may be damaged. There was a problem that sometimes. Such a phenomenon is particularly caused when two heat-resistant sheets forming a protective film portion are stacked in accordance with a requirement of a safety standard of withstand voltage in a temperature sensor, and the winding direction of the heat-resistant sheet is fixed. When the direction is parallel to the rotation direction of the heat roller, it is likely to appear remarkably. this is,
Because two heat resistant sheets of the same length were stacked,
Due to the difference in circumference between the outer sheet and the inner sheet,
In the wound state, the inner sheet is contracted by the outer sheet, so that the entire protective film portion is rounded and loses shape flexibility, and wrinkles are formed on the inner sheet by the influence of the surface shape. Therefore, it is easy to loosen. In addition, in the conventional temperature sensor, at the connection portion between the terminal plate and the external lead wire, when the core wire of the external lead wire is spot-welded to the terminal plate, the workability of welding is low,
There was a problem that it was difficult to keep the strength of the welded portion constant. This is because the core wires of the external lead wires are directly spot-welded, so that the core wires are disjointed, making it difficult to perform a welding operation, and it is difficult to weld all the wires constituting the core wire.

In addition, the conventional temperature sensor has a problem that it is difficult to reduce the size of a connection portion with an external lead wire and to provide this portion with sufficient strength.
This is because there is a limit to reducing the width and thickness of the terminal board to keep the strength of the connection part, and because the insulation tube is used for insulation and reinforcement of the connection part, This is because the size cannot be avoided. In addition, in the method in which the terminal accommodating portion is provided in the terminal plate portion to inject the resin, it is difficult to use the resin in the high-temperature portion because of the heat resistance of the injected resin. is there. Further, the conventional temperature sensor has a problem that it is difficult to route the external lead wires. This is because in the conventional temperature sensor, an external lead wire is drawn out for each thermistor element, and the drawing direction of the external lead wire is not always compatible with the structure of the device.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned circumstances, and has good thermal responsiveness and instability due to good adhesion to the rotating body surface when measuring the surface temperature of the rotating body. Further, it is another object of the present invention to provide a temperature sensor in which connection of an external lead wire is reliable and wiring can be easily routed.

[0013]

Means for Solving the Problems To solve the above problems, the invention according to claim 1 relates to a temperature sensor, in which a cushion material piece is attached to an upper surface of a support base, and heat conduction is performed on the top of the cushion material piece. Two heat-resistant sheets of different lengths are attached to the sensor section with the thermistor element fixed via the body thin film, with one end of the heat-resistant sheets being overlapped so that the shorter heat-resistant sheet is on the inside. After fixing the overlapped end to the lower surface of the support, winding the cushion material piece and the thermistor element so as to cover the same, and fixing the end of the winding end to the lower surface of the support, The first perforation provided at the beginning of winding of the heat-resistant sheet coincides with one corner of the lower surface of the support table, and the second perforation provided at the end of winding of the heat-resistant sheet. Is under the support In addition, the inner heat-resistant sheet covers the thermistor element and the heat conductor thin film portion, and the end of the winding end of the second sewing machine A protective film portion whose length is determined so as not to reach the eyes is provided, and the rotating direction of the protective film portion is perpendicular to the rotation axis of the rotating body whose surface temperature is to be measured. It is characterized by being held against. According to a second aspect of the present invention, there is provided the temperature sensor according to the first aspect, wherein another thermal conductive thin film is provided on the thermistor element, and the protective film portion is formed including the thermal conductive thin film. It is characterized by that.

According to a third aspect of the present invention, there is provided the temperature sensor according to the first or second aspect, wherein an internal conductor is buried inside the support and a mounting portion connected to the support. Forming a sensor terminal portion by exposing the internal conductor to the portion, connecting a lead wire of the thermistor element to the sensor terminal portion, and providing a lead groove at an end of the support base and an end of the mounting portion. An external lead wire that has been subjected to a terminal treatment by a terminal fitting is accommodated in the lead groove portion, and the inner conductor is exposed in the lead groove portion to form a lead terminal portion, and the terminal fitting portion is formed on the lead terminal portion. The connection of the above-mentioned external lead wires is performed by welding the above-mentioned portions. According to a fourth aspect of the present invention, there is provided the temperature sensor according to any one of the first to third aspects, wherein the mounting portion is connected to the support bases provided at both ends thereof to form a base portion. The sensor portions are formed on the respective support bases, and external lead wires for both sensor portions are pulled out at one end of the base portion in the same direction as the base portions. It is characterized by being. According to a fifth aspect of the present invention, there is provided the temperature sensor according to any one of the first to fourth aspects, wherein a cavity is formed in the cushion member piece below a heat conductive thin film provided below the thermistor element. Is formed. According to a sixth aspect of the present invention, there is provided the temperature sensor according to the fifth aspect, wherein the cavity has a closed structure.

[0015]

According to the structure of the present invention, in a temperature sensor in which a thermistor element is attached to the top of a cushion material piece via a metal foil, a protective film portion is formed by winding two heat-resistant sheets on top of each other and supporting the protective film portion. A perforation is provided so as to correspond to both corners of the lower surface of the table, and the inner heat-resistant sheet is shortened so that the end does not reach the perforation on the winding end side. The winding direction of the section is held perpendicular to the rotation axis of the rotating body whose surface temperature is to be measured, so that the protective film section and the surface of the rotating body of the surface temperature measurement object such as the fixing heat roller are fixed. As well as improving the adhesiveness, it is possible to prevent the thermal responsiveness from being lowered or becoming unstable due to the influence of the surface shape of the protective film portion. Possible to reduce the size of the difference. In another configuration of the present invention, the inner conductor is embedded inside the support and the mounting portion, and a lead groove is provided at an end of the support or the mounting portion,
An external lead wire is accommodated by accommodating an external lead wire that has been subjected to terminal treatment by a terminal fitting, and welding the terminal fitting portion to a lead terminal portion formed by exposing an internal conductor in a lead groove portion. As a result, the connection with the external lead wire becomes easy, and the external lead wire can be reliably held even at a high temperature.
There is no danger of disconnection of the connection part. In another configuration of the present invention, the external lead wires of the two sensor portions are configured to be drawn out at one end of the base portion in the same direction as the base portion. This facilitates the routing of the wiring. Further, according to another configuration of the present invention, since a cavity is formed in a portion of the cushion material piece below the heat conductive thin film for fixing the thermistor element, heat dissipation from the thermistor element is reduced, and the temperature sensor is provided with The accuracy of temperature measurement is improved, and the influence of the heat capacity of the cushion material piece on the thermistor element is reduced, so that the response speed of the temperature sensor is improved.

[0016]

Embodiments of the present invention will be described below with reference to the drawings. The description will be specifically made using an embodiment. FIG. 1 is a diagram showing an entire configuration of a temperature sensor according to an embodiment of the present invention, FIG. 2 is a diagram showing a configuration of a measuring unit in the embodiment, and FIG. 3 is a diagram of a base member in the embodiment. FIG. 4 is a diagram showing a configuration of a first sensor unit in the present embodiment, FIG. 5 is a diagram showing a configuration of a second sensor unit in the present embodiment, and FIG. FIG. 7 is a diagram illustrating another configuration example of the sensor unit, FIG. 7 is a diagram illustrating another configuration example of the second sensor unit, FIG. 8 is a diagram illustrating the configuration of the protection film unit in the present embodiment, and FIG. FIG. 3 is a diagram illustrating a configuration of a lead wire connection unit in the embodiment. As shown in FIG. 1, the temperature sensor of this example includes a base unit 1, a first sensor unit 2, a second sensor unit 3, an external lead wire unit 4, and a connector unit 5. Have been. The base 1 is the first
Is a base of the entire temperature sensor, including the sensor section 2 and the second sensor section 3, and is made of, for example, a heat-resistant resin molded product. When attached to (not shown) or the like, the first sensor unit 2 and the second sensor unit 3 are spatially supported at fixed positions. The first sensor unit 2 and the second sensor unit 3
Each of the measuring units including the thermistor element unit comes into contact with, for example, the surface of a toner fixing heat roller (not shown) of a copying machine to measure the surface temperature. The external lead wire portion 4 is made of a heat-resistant insulated wire, and outputs the respective output signals of the first sensor portion 2 and the second sensor portion 3 to the connector portion 5.
Connect to The connector section 5 connects each lead wire of the external lead wire section 4 to an input section of a copying machine or the like (not shown).

Next, with reference to FIG. 2, a detailed configuration of the measuring section in the temperature sensor of this example will be described. In FIG.
(A) is a top view, (b) is a front view, and (c) is a bottom view. The base 1 includes a central mounting portion 11,
The first support base 12 provided on the left and right of the mounting portion 11 and the second support base 12
And a support 13. The mounting portion 11 has mounting holes 14 and 15, and can be mounted on a housing of a copying machine or the like using these portions. First support 1
2, the second support 13 is provided with the first sensor unit 2,
This is a portion serving as a support for the second sensor unit 3. In the first sensor section 2, a cushion material piece 16 is adhered to the upper surface of the first support base 12, and the top of the cushion material piece 16 is sandwiched between two heat conductive thin films. In this state, the thermistor element 17 is attached. The two lead wires 18 and 19 of the thermistor element 17 are connected to sensor terminal portions 20 and 21 provided on the lower surface of the first support 12.
It is connected to the. In the second sensor section 3, a cushion material piece 22 is adhered to the upper surface of the second support base 13, and a thermistor element 23 is provided on the top of the cushion material piece 22 via a heat conductor thin film. Installed. Two lead wires 24, 25 of the thermistor element 23
Are connected to sensor terminals 26 and 27 provided on the lower surface of the second support 13. Cushion pieces 16,2
2 is made of, for example, a soft heat-resistant foamed resin material, but may be another material.

The mounting portion 11 includes a lead terminal portion 2.
8, 29A and 29B are provided, and a lead terminal 30 is provided on the second support 13.
The lead terminal portion 28 is formed of one end of an internal conductor exposed on both upper and lower surfaces of the mounting portion 11, and an external lead wire 31 is connected to the exposed portion on the upper surface side. Lead terminal 29A, 29B
Consists of internal conductors exposed on both upper and lower surfaces of the mounting portion 11. The lead terminal portion 29A is an exposed portion on the lower surface side of the mounting portion 11, to which an external lead wire 32 is connected. The lead terminal 29B is an exposed portion on the upper surface side of the mounting portion 11, to which an external lead wire 33 is connected. Further, the lead terminal portion 30 is formed of one end of an internal conductor exposed on both upper and lower surfaces of the second support base 13, and an external lead wire 34 is connected to an exposed portion on the lower surface side. External lead wire 3
1, 32, 33, and 34 form the external lead wire portion 4. Further, the cushion member 16 and the thermistor element 17
And a protective film portion 35 is provided to cover the cushion member 22 and the thermistor element 23. The protective film portions 35 and 36 are made of, for example, a flexible film material having heat resistance and high withstand voltage such as a polyimide film. In the temperature sensor of this example, the mounting portion 11 is arranged such that the base 1 is parallel to the rotation axis of the fixing heatroherer and the thermistor elements 17 and 23 of the sensor portions 2 and 3 are in contact with the surface of the heatroherer. It is used by being attached to the housing of the copier by the mounting holes 14 and 15 provided in the printer. In this state, the sensor units 2 and 3
Are held so that the winding direction thereof is perpendicular to the rotation axis of the heat roller.

Next, with reference to FIG. 3, a detailed configuration of the base portion in the temperature sensor of this example will be described. In FIG.
(A) is a top view, (b) is a front view, and (c) is a bottom view. Inside the base 1, internal conductors 37, 38, and 39 made of a thin metal plate are embedded.
One end of the internal conductor 37 is exposed on the upper and lower surfaces of the first support base 12 to be the sensor terminal portion 20, and the other end is exposed on the upper and lower surfaces of the mounting portion 11 to be the lead terminal portion 28. . One end of the internal conductor 38 is connected to the first support 1.
2 are exposed on both upper and lower surfaces to form a sensor terminal portion 21, and the other end is exposed on both upper and lower surfaces of the mounting portion 11 to become a lead terminal portion 29A and become a lead terminal portion 29B. The sensor terminals 26 are exposed on both upper and lower surfaces of the table 13. One end of the internal conductor 39 is exposed on both the upper and lower surfaces of the second support 13 to form the sensor terminal portion 27, and the other end is exposed on both the upper and lower surfaces of the end of the second support 13 and the lead terminal portion is formed. It is 30. Grooves 40 and 41 are provided on the lower surface of the first support 12 to accommodate the leads 18 and 19 of the thermistor element 17, respectively, and the groove 42 is provided on the lower surface of the second support 13. , 43 are provided to accommodate the leads 24, 25 of the thermistor element 23, respectively. The exposed portions on the upper and lower surfaces of the inner conductor are necessary when resistance welding is performed by sandwiching the inner conductor and the tip of the external lead wire from both the upper and lower surfaces.

Next, a detailed configuration of the first sensor section 2 in the temperature sensor of this example will be described with reference to FIG. 4, (a) shows a front view, and (b) shows the A-
FIG. The first sensor unit 2 has a cushion member 16 made of, for example, a soft heat-resistant foamed resin material fixed to the upper surface of the first support base 12, and a disc-shaped lower heat conductor thin film 51, for example, on the top thereof. Is provided, and the thermistor element 17 is disposed thereon, and further, for example, a disc-shaped upper heat conductor thin film 52 is further placed thereon. The leads 18, 19 of the thermistor element 17 are
Each is connected to sensor terminal portions 20 and 21 provided on the lower surface of the first support base 12. Further, a protective film portion 35 is provided so as to cover the entirety.

Next, a detailed configuration of the second sensor section 3 in the temperature sensor of this example will be described with reference to FIG. 5A shows a front view, and FIG.
FIG. The second sensor unit 3 has a cushion material piece 22 made of, for example, a soft heat-resistant foamed resin material fixed on the upper surface of the second support table 13, and a disc-shaped heat conductor thin film 54, for example, on the top thereof. And the thermistor element 23 is disposed thereon. Lead wires 24, 25 of the thermistor element 23 are connected to sensor terminal portions 26, 27 provided on the lower surface of the second support 13, respectively. Further, a protective film portion 36 is provided so as to cover the entirety.

In these examples, the heat conductor thin film 51,
As the materials 52 and 54, for example, a thin and flexible film material having good heat conductivity such as a metal foil such as aluminum (Al) or a polyimide film or a silicon film can be used.

Next, another configuration example of the first sensor section 2 in the temperature sensor of this embodiment will be described with reference to FIG. 6, (a) shows a front view, and (b) shows the A-
FIG. The first sensor unit 2 has a cushion member 16A made of, for example, a soft heat-resistant foamed resin material fixed on the upper surface of the first support base 12, and a disc-shaped lower heat conductor thin film 51, for example, on the top thereof. Is provided, and the thermistor element 17 is disposed thereon, and further, for example, a disc-shaped upper heat conductor thin film 52 is further placed thereon. Lead wires 18 and 19 of thermistor element 17
Are connected to sensor terminals 20 and 21 provided on the lower surface of the first support base 12, respectively. Further, a protective film portion 35 is provided so as to cover the entirety. The above configuration is the same as that of the sensor section shown in FIG. 4A, but in the example of FIG. 6, the cushion material piece 16A has a slightly smaller diameter than the thin film 51 below the lower heat conductive thin film 51. For example, having a cylindrical cavity 53. The cavity 53 forms a closed space together with the lower thermal conductive thin film 51 and the upper surface of the support base 12.

In the example shown in FIG. 6, since the lower portion of the lower heat conductive thin film 51 is a closed space, heat dissipation from this portion is reduced as compared with the structure of FIG. The temperature measurement accuracy of the sensor is improved, and the influence of the heat capacity of the cushion material piece 16A on the thermistor element 17 is reduced, so that the response speed of the temperature sensor is improved.

Next, another configuration example of the second sensor section 3 in the temperature sensor of this embodiment will be described with reference to FIG. 7A shows a front view, and FIG.
FIG. The second sensor unit 3 has a cushion material piece 22A made of, for example, a soft heat-resistant foamed resin material fixed on the upper surface of the second support base 13, and a disc-shaped heat conductor thin film 54, for example, on the top thereof. And the thermistor element 23 is disposed thereon. Lead wires 24, 25 of the thermistor element 23 are connected to sensor terminal portions 26, 27 provided on the lower surface of the second support 13, respectively. Further, a protective film portion 36 is provided so as to cover the entirety. The above configuration is shown in FIG.
7, the cushion member 22A has a hollow portion 55 having a diameter slightly smaller than that of the thin film 54, for example, a cylindrical hollow portion 55 below the heat conductive thin film 54 in the example of FIG. Is different. The cavity 55 forms a closed space together with the heat conductor thin film 54 and the upper surface of the support base 13.

In the example of FIG. 7, since the lower portion of the heat conductor thin film 54 is a closed space, heat dissipation from this portion is reduced as compared with the structure of FIG. Temperature measurement accuracy is improved and the thermistor element 2
3, the effect of the heat capacity of the cushion material piece 22A is reduced, so that the response speed of the temperature sensor is improved.

Next, referring to FIG. 8, a detailed configuration of the protective film portions 35 and 36 in the temperature sensor of this example will be described. In FIG. 8, (a) is a perspective view showing a shape developed on a plane before winding of a heat-resistant sheet constituting a protective film portion, and (b) is a state in which the heat-resistant sheet is attached to each sensor portion. FIG. 5 is a perspective view showing a shape in a state where protective film portions 35 and 36 are formed. Before being attached to the sensor unit, the protective film unit is composed of two heat-resistant sheets 61 and 62 formed of a heat-resistant resin film such as a polyimide film as shown in FIG. The length L2 of the other heat resistant sheet 62 is set to be slightly shorter than the length L1 of the other heat resistant sheet 61. And one heat resistant sheet 61 is
Heat-resistant adhesives 63 and 64 are applied to both lower ends thereof, and a similar adhesive 65 is applied to the other heat-resistant sheet 62 at one lower end thereof. Furthermore, broken lines (perforations) 66, 6 are provided at predetermined distances from the ends of the heat-resistant sheets 61, 62 on which the adhesives 63, 65 are applied.
7, and a perforation 68 is provided at a predetermined distance from the other end of the heat-resistant sheet 61 on which the adhesive 64 is applied.

When the protective film portions 35 and 36 are formed, one end of the heat resistant sheets 61 and 62 are aligned and overlapped, and the heat resistant sheets 61 and 62 are joined with the adhesive 63 in the longitudinal direction on the lower surfaces of the support tables 12 and 13. Is adhered to one end of the base with an adhesive 65, and then loosely wound including the whole of the cushioning material pieces and the like attached to the support base. The heat-resistant sheet 61 is placed on the heat-resistant sheet 61 and the end of the heat-resistant sheet 61 is coated with the adhesive 6.
4 by bonding and fixing with FIG.
Into a shape as shown in FIG. At this time, perforation 66,
67 corresponds to the position of one longitudinal corner on the lower surface of the support base (not shown), and the perforation 68 matches the position of the other longitudinal corner on the lower surface of the support base. Each position is predetermined. Also,
When the heat-resistant sheet 62 on the inner side is wound, the shortened end 69 sufficiently covers the cushion material piece, the thermistor element, and the heat conductive thin film, and reaches the position of the perforation 68. So that its length L
2 is set.

Next, referring to FIG. 9, a detailed configuration of a connection portion of an external lead wire in the temperature sensor of this example will be described. In FIG. 9, (a) shows the terminal processing of the lead wire,
(B) shows the connection state between the lead wire terminal and the lead wire. The external lead wires 31, 32, 33, and 34 have terminal fittings 71 attached to their terminals. Terminal fitting 71
Has two pairs of claws 72 and 73 on the same metal fitting. The claw portion 72 is large and is used to surround and fasten and fix the covering portion of the lead wire. The claw portion 73 is small and is used to surround and tighten and fix the core portion of the lead wire. Each external lead wire 31,3
2, 33, 34 are previously provided with terminal fittings 7 on their respective terminals.
9 is formed into a shape as shown in FIG.

In FIG. 9B, the external leads 34
And the connection state with the lead terminal unit 30 is illustrated,
The same applies to the connection states of the other external lead wires 31 and the lead terminal portions 28, the external lead wires 32 and the lead terminal portions 29A, and the external lead wires 33 and the lead terminal portions 29B. The lead terminal portion 30 is provided on the lower surface of the support base 13 such that one end of the internal conductor 39 is exposed to the outside through a hole 74 provided in the support base 13. Further, a lead groove portion 75 having a width large enough to accommodate the terminal-processed end of the external lead wire 34 is provided in the lead wire connection portion of the support 13. One end of the lead groove 75 is open. When connecting the external lead wire 34 and the lead wire terminal portion 30,
The end of the external lead wire 34 is inserted into the lead groove 75, and in this state, the terminal fitting 7 at the end of the external lead wire 34 is inserted.
The electrical connection and the mechanical fixing are performed by forming, for example, a spot welded portion 78 on the lead terminal portion 30 by spot welding.

Next, the operation of the temperature sensor of this embodiment will be described with reference to FIGS. The temperature sensor in this example is
For example, using the mounting holes 14 and 15 provided in the mounting portion 11 of the base portion 1, the mounting portion is fixed and mounted on a support portion (not shown) provided in a part of a housing of a copying machine or the like. Thereby, the thermistor elements 17 and 23 of the first sensor unit 2 and the second sensor unit 3 are respectively connected to the protective film units 35 and 36.
Through the surface of a heat-measuring object, for example, a toner fixing heat roller (not shown) of a copying machine, and the surface temperature can be measured regardless of the rotation or non-rotation of the roller. . At this time, the protective film portions 35 and 36 of the sensor portions 2 and 3 are held so that the winding direction is perpendicular to the rotation axis of the heat roller. The thermistor elements 17 and 23 are connected to lead wires 18 and 19, respectively.
, And 24 and 25, are connected to the sensor terminals 20, 21 and 26 and 27, and are further connected to the internal conductors 37, 38, 3
9 to lead terminal portions 28, 29A, 29B, 30 and further to external lead wires 31, 32 and 33, 34, thereby providing connector portion 5
Are connected to respective measurement circuits (not shown). The thermistor elements 17 and 23 each generate an output indicating a change in the internal resistance of the fixing heat roller according to the surface temperature of the fixing heat roller, and the measuring circuit generates an electric signal corresponding to the surface temperature of the roller according to the output. Each control circuit (not shown) performs temperature control to keep the surface temperature of the roller constant by changing the heating state of the roller in accordance with the output of the thermistor element 17, and controls the thermistor element 23. Depending on the output, when the roller surface temperature exceeds a certain value,
Abnormal control such as stopping the heating of the roller is performed.

In the temperature sensor of this example, as shown in FIGS. 4 to 7, in the sensor sections 2 and 3, the thermistor elements 17 and 23 respectively include a lower heat conductive thin film 51 and
In a state held by the heat conductive thin film 54, the heat conductive thin film 54 is supported on the tops of the cushion material pieces 16 and 22, respectively. The lower heat conductor thin film 51 and the heat conductor thin film 54 transfer the heat of the surface of the fixing heat roller to the thermistor elements 17 and 23 to reduce the temperature of the thermistor elements 17 and 23.
Quickly follow the roller surface temperature. Also, the lead wires 18, 19 and 24, 25 of the thermistor elements 17, 23 are provided.
Are cushion material pieces 16 and 2 having small thermal conductivity.
2 and the support bases 12 and 13, the heat conduction from this part is also small. The thermistor element 17
In this case, the upper thermal conductive thin film 52 is further provided, and the lower thermal conductive thin film 51 and the upper thermal conductive thin film 52 cover both sides, thereby further improving the sensitivity to a temperature change. As a result, the sensor units 2 and 3
The temperature measurement time constant is significantly improved as compared with the conventional temperature sensor, and the temperature of the fixing heat roller can be precisely controlled.

Further, in the configurations of FIGS. 6 and 7, since the hollow portions 53 and 55 are provided below the thermistor elements 17 and 23, heat conduction via the cushion material immediately below the thermistor element is reduced, and the cushion material is used. Based heat capacity was reduced, and thermal responsiveness was further improved. Thus, the temperature measurement time constant τ in the case of the conventional structure is 0.5 seconds to 0.
In this example, the temperature measurement time constant τ
Is 0.2 seconds to 0.4 seconds, which is significantly improved.

6 and 7, the lower heat conductive thin film 51 and the heat conductive thin film 54 are bent toward the cushion member, and the thermistor elements 17 and 23 are accommodated in the bent portions. Since the sensor portion can be formed so that the portion is pushed into the hollow portions 53, 55 provided in the cushion members 12, 13, the unevenness of the top portions of the sensor portions 2, 3 is reduced, and the protective film portion 35, 55 is formed. 36, the contact portion with the fixing heat roller can be smoothed.
Therefore, while the wear of the protective film part decreases,
The risk of damaging the roller surface is reduced.

In this example, as shown in FIGS. 4 to 7, in the sensor portions 2 and 3, the protective film portions including the support bases 12 and 13, the cushioning pieces 16 and 22 and the thermistor elements 17 and 23 are included. By surrounding by the rollers 35 and 36, wear due to the rotation of the roller is prevented, and the withstand voltage performance against a high voltage applied between the fixing heat roller and the thermistor element is improved. For this reason, as shown in FIG. 8, abrasion-resistant polyimide films or the like are used as the heat-resistant sheets 61 and 62 constituting the protective film portion, and two sheets are laminated to have voltage resistance and have a width W. Is made sufficiently large to prevent the occurrence of creeping discharge. The heat-resistant sheets 61, 62 are provided with perforations 66, 67, 68, so that when the protective films 35, 36 are formed by attaching to the sensors, both corners of the lower surfaces of the supports 12, 13 are formed. By bending at the corners, the shapes of the protective film portions 35 and 36 are less rounded, and the adhesion between the heat-resistant sheet and the thermistor element is improved.
Due to the heat of the fixing heat roller, the adhesive 63, 64, 6
Even if 5 deteriorates, the risk of the heat-resistant sheet coming off due to the elasticity of the heat-resistant sheet is reduced. Further, at this time, perforations 66, 67 and 68 are provided, and the protective film portion 3 is provided.
5 and 36 are bent at both corners of the lower surface of the support bases 12 and 13, so that the protective film portions 35 and 36 are bent.
Is rounded in an elongated shape like an eggplant, and the width in the direction orthogonal to the base 1 is reduced, so that the size of the sensor unit including the protective film unit can be reduced.

The length L2 of the heat-resistant sheet 62 on the inner side is shorter than the length L1 of the heat-resistant sheet 61 on the outer side.
8 and the end 69 is not provided with an adhesive, so that the end 69 is
In a state where 36 is formed, the heat-resistant sheet 61 on the outside is in a free state. Therefore, when two heat-resistant sheets are stacked and wound, the inner heat-resistant sheet is contracted by the outer heat-resistant sheet, so that the protective film portion is rounded and loses flexibility, or It is possible to prevent the inner heat-resistant sheet from wrinkling due to the contraction, and therefore, the adhesion of the thermistor element to the fixing heat roller via the heat-resistant sheet is improved, and the thermal responsiveness of the temperature sensor is improved. It is possible to prevent a decrease and an unstable state from occurring.

In this example, as shown in FIG. 9, the lead wires 31, 32, 33, 34
Terminal processing using the lead terminals 18, 29A,
29B and 30 are connected by spot welding at the terminal fittings. Conventionally, at the time of connection between the lead wire and the terminal part, spot-welding or soldering of the core wire part that has been subjected to processing such as coating removal directly to the terminal plate without performing terminal treatment on the lead wire with terminal fittings However, at this time, since the wires constituting the core wire are likely to be separated, not only is the workability bad, but also
It is difficult to reliably connect the entire core wire, and thus it is easy to cause poor connection, and it is difficult to keep the strength of the connection portion uniform. In addition, when a lead wire is bent when a temperature sensor is attached to a device, a bending stress is applied to a welded or soldered portion of the core wire, so that disconnection is likely to occur at the connection portion. In this example, the terminal wire is subjected to a terminal treatment for separately holding the covering portion and the core wire portion using the terminal metal fitting 71, and then the terminal metal portion is welded. And when bending force is applied to the lead wire, the bending stress is outside the portion held by the terminal fittings.
Since it is applied to the portion of the lead wire that has not been welded or soldered, it is less likely that the wire will break due to bending.

Further, in this example, as shown in FIG.
An external lead wire is accommodated in a lead groove portion 75 provided in the longitudinal direction of the base portion 1 so as to be connected to a lead terminal portion. Conventionally, the connection between the sensor unit and the external lead wire is
Insulation and mechanical holding are performed by welding or soldering the lead wire to the metal terminal plate provided on the resin molded body and covering the insulating tube including the terminal portion and the end of the external lead wire. However, the strength of the terminal plate needs to be increased, and the outer shape of the connection portion including the insulating tube has been increased. In this example, since there is the lead groove portion 75 for accommodating the connection portion between the external lead wire and the lead terminal portion, the holding of the external lead wire is ensured, and the bending force on the external lead wire is transmitted to the lead wire connection portion. Is prevented. for that reason,
The inner conductor constituting the lead terminal portion may be thin.
Furthermore, even if an insulating tube is not used for the connection portion, contact of the charged portion can be prevented, so that the entire temperature sensor can be reduced in size, and a decrease in heat resistance based on the insulating tube can be prevented. Further, since the connection between the external lead wire and the lead terminal portion is performed in the lead groove portion, the positioning and holding at the time of spot welding becomes easy, and the workability and the quality of the connection portion can be improved.

Further, since all the lead grooves for accommodating the lead wire connecting portions are provided collectively on one end side of the base portion in the longitudinal direction of the base portion 1, a plurality of external lead wires are provided. All together and connected to the connector unit 5 easily. Conventionally, in a temperature sensor having a plurality of sensor portions, the direction of the lead wire was, for example, a direction perpendicular to the longitudinal direction of the base portion, so that the lead portion of the lead wire became longer and required more space, Although this hindered the miniaturization of the equipment, in this case, the above-described structure facilitated the routing of the wiring and reduced the space for the wiring. The temperature sensor can be mounted with the same number of work steps as in the case of a temperature sensor having a single thermistor element, which can contribute to cost reduction.

Although the embodiment of the present invention has been described in detail with reference to the drawings, the specific configuration is not limited to this embodiment, and there are design changes and the like without departing from the gist of the present invention. Even this is included in the present invention. For example, in the embodiment, the soft heat-resistant foaming resin material is used as the cushioning material pieces 16 and 22. However, the present invention is not limited to this. For example, short fibers made of glass or the like are assembled into a thin asbestos sheet by a paper making process. In this case, an inorganic fiber paper (for example, ceramic paper) may be used, whereby the heat resistance can be further improved. Further, the protective film portions 35 and 36 do not necessarily have to go around the support tables 12 and 13, and one end of the two heat-resistant sheets is fixed to one end of the lower surface of the support table, for example. May be fixed to the other end of the lower surface of the support base. As a fixing method in this case, the end portion of the heat-resistant sheet may be fixed with another member, or the end portion of the heat-resistant sheet may be bent and inserted into the slit portion. Further, the shape of the hollow portions 53 and 55 is not limited to a cylindrical shape, and may be an arbitrary shape such as a rectangular tube to a polygonal tube, or an irregular tube. It is most desirable that this cavity has a closed structure, but it is not necessarily limited to this. For example, even if the lower end is open or semi-closed, at least the lower heat conductor that supports the thermistor element Thin film 5
The effect of reducing the heat capacity due to the fact that the first or heat conductor thin film 54 does not contact the cushion material piece can be obtained, and the response speed of the temperature sensor can be improved. The lower thermal conductive thin film 51, the upper thermal conductive thin film 52, and the thermal conductive thin film 54 are not limited to a disk shape, but may be a rectangular plate shape, a polygonal plate shape, or an irregular plate shape.

[0041]

As described above, according to the present invention, a protective film portion is provided for a sensor portion, and its winding direction is perpendicular to the rotation axis of a rotating body whose surface temperature is to be measured. So that it is held against the rotating body, perforations are provided at both corners of the lower surface of the support base with respect to the protective film part of the sensor part, and the inner heat-resistant sheet is shortened to make the end part free As a result, the protective film part becomes rounded and loses flexibility, and the adhesiveness to the rotating body is reduced due to the influence of the surface shape. And the width of the protective film portion is reduced, so that the temperature sensor can be downsized. In addition, the external lead wire that has been subjected to the terminal treatment by the terminal fitting is accommodated in the lead groove portion, and the terminal fitting portion is welded to the lead terminal portion of the internal conductor in the lead groove portion to connect the external lead wire. Because
The external lead wire can be securely held, and the connection with the external lead wire is facilitated, so that there is no danger of disconnection of the connection portion. Furthermore, since the external lead wires for the two sensor portions are drawn out in the same direction as the base portion at one end of the base portion, the wiring of the external lead wires can be easily routed. Further, if a cavity is provided in the cushion material piece below the heat conductor thin film on which the thermistor element is mounted, the influence of the heat conduction and heat capacity based on the cushion material piece on the thermistor element is reduced. Accuracy and response speed can be improved.

[Brief description of the drawings]

FIG. 1 is a diagram showing an entire configuration of a temperature sensor according to an embodiment of the present invention.

FIG. 2 is a diagram illustrating a configuration of a measurement unit according to the present embodiment.

FIG. 3 is a diagram illustrating a configuration of a base member according to the present embodiment.

FIG. 4 is a diagram illustrating a configuration of a first sensor unit in the present embodiment.

FIG. 5 is a diagram illustrating a configuration of a second sensor unit in the present embodiment.

FIG. 6 is a diagram illustrating another configuration example of the first sensor unit.

FIG. 7 is a diagram illustrating another configuration example of the second sensor unit.

FIG. 8 is a diagram illustrating a configuration of a protective film unit in the present embodiment.

FIG. 9 is a diagram showing a configuration of a lead wire connection unit in the present embodiment.

FIG. 10 is a diagram illustrating a configuration example of a conventional temperature sensor.

FIG. 11 is a diagram showing another configuration example of a conventional temperature sensor.

FIG. 12 is a diagram showing another configuration example of a conventional lead wire connection unit.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Base part 2 1st sensor part 3 2nd sensor part 4 External lead wire part 5 Connector part 12,13 Support base 16,22 Cushion material piece 17,23 Thermistor element 18,19,24,25 Lead wire 20 , 21, 26, 27 Sensor terminal portions 28, 29A, 29B, 30 Lead terminal portions 31, 32, 33, 34 External lead wires 35, 36 Protective film portions 37, 38, 39 Internal conductors 51 Lower thermal conductor thin film 52 Upper portion Thermal conductor thin film 53, 55 Cavity 54 Thermal conductor thin film 66, 67, 68 Perforation

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Shinya Tonogawa 2-7-18 Machiya, Urawa-shi, Saitama F-term (reference) 2F056 QF02 QF05 QF07 QF08

Claims (6)

[Claims] 1. A sensor member comprising a cushion member attached to an upper surface of a support base and a thermistor element fixed to a top portion of the cushion member via a heat conductive thin film. The heat-resistant sheet of the above is laminated and bonded with one end overlapped so that the shorter heat-resistant sheet is on the inside, and the overlapped end is fixed to the lower surface of the support base, and then the cushion material piece and the thermistor element And wrap it around
The end of the winding end is fixed to the lower surface of the support base, and the first perforation provided at the start of winding of the heat resistant sheet coincides with one corner of the lower surface of the support base. And the second perforation provided at the end of the winding of the heat-resistant sheet is aligned with the other corner of the lower surface of the support base, and further, the inner heat-resistant sheet is While covering the thermistor element and the heat conductive thin film, the end of the winding end is the second end.
A protective film portion having a length determined so as not to reach the perforation of the rotator, so that the winding direction of the protective film portion is perpendicular to the rotation axis of the rotating body whose surface temperature is to be measured. A temperature sensor held against a rotating body. 2. The temperature sensor according to claim 1, wherein another thermal conductive thin film is provided on the thermistor element, and the protective film portion is formed including the thermal conductive thin film. 3. A sensor terminal part is formed by burying an internal conductor inside the support base and a mounting part connected to the support base, exposing the internal conductor to the support base part, and forming a sensor terminal part. A lead wire of the thermistor element is connected to the portion, a lead groove portion is provided at an end of the support base and an end portion of the mounting portion, and an external lead wire that has been subjected to terminal processing by a terminal fitting is accommodated in the lead groove portion. And connecting the external lead wire by exposing the internal conductor in the lead groove portion to form a lead terminal portion, and welding the terminal fitting portion to the lead terminal portion. Claim 1
Or the temperature sensor according to 2. 4. The mounting part and the support bases provided at both ends thereof are connected to form a base part, and the sensor parts are formed on the respective support bases. The temperature sensor according to any one of claims 1 to 3, wherein an external lead wire is configured to be drawn out at one end of the base portion in the same direction as the base portion. . 5. The temperature sensor according to claim 1, wherein a cavity is formed in a lower portion of the heat conductive thin film provided below the thermistor element in the cushion material piece. . 6. The temperature sensor according to claim 5, wherein the cavity has a closed structure.