JP2007171268A - Fixing unit with built-in thermostat and printer or copying machine equipped with the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a fixing unit with built-in thermostat which comprises a small number of components, can inexpensively be manufactured, and can perform temperature detection with high thermal response property. <P>SOLUTION: The fixing unit with built-in thermostat is equipped with a ceramic heater 1, a holder 3 which holds the heater 1, a thermostat part 5 incorporated in the holder 3, and a fixing film 63 into which the holder 3 is rotatably inserted. The thermostat part 5 has a first terminal 7 and a second terminal 9 fixed to the holder 3, a fixed contact 11 provided to the first terminal 7, a movable contact 13 which contacts or moves away from the fixed contact 11, a movable spring 15 which energizes the movable contact 13 to the fixed contact 11, and a bimetal 19 which performs inverting operation at set upper-limit temperature to move a guide pin 17 upward and separate the movable contact 13 from the fixed contact 11 against the energizing force of the movable spring 15. The bimetal 19 is arranged in a through hole 25 bored in a bottom wall of the holder 3 and abuts against a top surface of the heater 1. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a fixing device that is used in a laser printer, a copying machine, and the like and melts toner with heat of a heater and fixes the toner on a print sheet. In particular, the present invention relates to a fixing device including a thermostat as a safety device in order to cut off the power supply to the heater when the temperature of the fixing device becomes abnormally high.

  As a fixing device attached to a laser printer or a copying machine, there is a so-called roller fixing method. This roller fixing method has a structure in which a halogen heater is incorporated in a metal cylindrical fixing roller. The fixing roller is heated by the radiant heat of the internal heater, and a thermostat is used to sense the temperature of the fixing roller.

  A thermostat is an electronic component that opens and closes connection terminals and switches between energization using a snap action of a disk-shaped bimetal according to a temperature change. That is, when the temperature rises to the set upper limit temperature, the connection terminals are disconnected by turning off the bimetal, and when the temperature drops to the set lower temperature, the connection terminals are closed by the return operation of the bimetal. Resume energization. In this case, by setting the lower limit temperature at which the bimetal recovers to a normal temperature or lower (for example, −35 ° C.), once the bimetal is reversely operated, the state is maintained and the final safety device against the failure of the device. Can function as.

  In the case of the roller fixing method, since a heater is disposed inside the fixing roller, there is no space for mounting the thermostat inside the fixing roller. Therefore, the thermostat was attached to the outside of the fixing roller.

  When a thermostat is attached to a roller fixing type fixing machine, there are two types, a case where it is brought into contact with a fixing roller and a case where it is not brought into contact. When the thermostat is brought into contact with the fixing roller, the heat responsiveness is good, but the fixing roller may be damaged. On the other hand, when the thermostat is not brought into contact with the fixing roller, the fixing roller is not damaged, but the thermal response is deteriorated.

  In addition, there is a fixing machine called an on-demand fixing method. This on-demand fixing type fixing machine has a structure in which a thin cylindrical fixing film is used instead of a fixing roller, and a ceramic heater is provided as a heater inside the fixing film. The ceramic heater is positioned, the fixing film in contact with the outer side of the ceramic heater rotates, and the ceramic heater heats only the contact portion between the fixing film and the pressure roller.

  In the case of this on-demand fixing method, the fixing film is heated only in the part in contact with the pressure roller. Since the fixing film and the heater are in direct contact, the temperatures of the fixing film and the heater are substantially the same. Therefore, detecting the temperature of the heater is the same as detecting the temperature of the fixing film, and an abnormality in the temperature of the fixing device can be detected.

Conventionally, in the on-demand fixing method, a thermal fuse is used to sense the temperature of the heater. In the case of the on-demand fixing method, the ceramic heater is made into a thin plate shape, so that it is possible to place a thermal fuse inside the fixing film, and it is necessary to bring a thermostat into contact with the fixing surface as in the roller fixing method. Absent.
JP-A-9-198980

  However, the thermal fuse used in the on-demand system has a cylindrical shape, and the thermal fuse is in line contact with the plane of the ceramic heater. In this case, heat conduction from the ceramic heater to the thermal fuse was poor, and thermal response was poor.

  Some thermal fuses use temperature-sensitive pellets. This temperature-sensitive pellet has a property that the melting temperature changes due to moisture absorption. If the device used is used in a high humidity atmosphere for many years, the operating temperature of the thermal fuse may change and the device used may malfunction.

  In addition, some temperature-sensitive pellets contain harmful substances for the environment, and no alternative substances have been found. In the future, when this hazardous substance is banned, there is a problem that a temperature fuse using the temperature sensitive pellet cannot be manufactured.

  Furthermore, once the thermal fuse is operated, it cannot be returned to the original state, and the operation can be confirmed only by sampling inspection. Therefore, since 100% inspection cannot be performed, even if the temperature-sensitive pellet is melted, the spring inside the thermal fuse may be caught and the current may not be interrupted.

  By the way, as shown in Patent Document 1, the conventional thermostat is assembled as a plurality of parts, and is configured as a single independent part. That is, the bimetal (15) is provided in the cylindrical base (8) and the cap (16) is covered. Note that the numbers in parentheses indicate the signs in Patent Document 1. Since the bimetal in the conventional thermostat is disposed in the space covered with the cap, the heat transfer property to the bimetal and thus the thermal response is inferior. In addition, as long as the thermostat is captured as an independent component by being bound by a conventional concept, it is not possible to reduce the number of components and hence the product cost.

  The problem to be solved by the present invention is that a thermostat with a higher reliability than a thermal fuse can be sensed and a fixing device with a built-in thermostat with a small number of parts, and a laser printer and a copying machine including the fixing device are provided. It is to provide.

  The present invention has been made to solve the above-described problems, and includes a holder having a heater on the bottom wall bottom surface, and a cylindrical fixing film into which the holder is inserted, and the holder includes the heater. A thermostat built-in fixing machine having a case of a thermostat having an open / close contact that interrupts energization to the metal in response to a snap action of the bimetal. Here, preferably, the thermostat-containing fixing device is characterized in that a ceramic heater as the heater is overlapped and fixed to the bottom surface of the bottom wall of the holder made of synthetic resin.

  Also, the present invention has a substantially rectangular plate-like bottom wall that is elongated to the left and right, and ribs are formed extending upward and downward on both front and rear side edges of the bottom wall. The bottom wall penetrates vertically. A holder formed with an opening, a substantially rectangular plate-shaped ceramic heater fixed to the lower surface of the bottom wall of the holder, and an upper surface of the ceramic heater disposed in the opening of the holder and exposed from the opening A bimetal provided in direct contact, an open / close contact that cuts off power to the ceramic heater according to a snap action of the bimetal, and a cylindrical fixing in which the holder with the ceramic heater is inserted and accommodated And a thermostat built-in fixing device.

  Also, the present invention has a substantially rectangular plate-like bottom wall that is elongated on the left and right sides, and ribs are formed by extending upward at both front and rear sides of the bottom wall, and the bottom wall has a recess that opens downward. The formed holder, a substantially rectangular plate-shaped ceramic heater fixed to the bottom surface of the bottom wall of the holder, a bimetal disposed in the recess of the holder, and the ceramic heater according to a snap operation of the bimetal A thermostat built-in type fixing device comprising: an open / close contact that interrupts energization of the electrode; and a cylindrical fixing film in which the holder with the ceramic heater is inserted and accommodated.

  Further, the present invention is provided such that any one of the thermostat built-in type fixing device and the thermostat built-in type fixing device is rotatably provided with a print sheet interposed therebetween, and is heated by the ceramic heater through the fixing film. Thus, the laser printer or the copying machine includes a pressure roller for fixing the toner to the print paper.

  According to each of the above inventions, a thermostat having higher reliability than a thermal fuse can be incorporated in the holder of the fixing device. Further, compared to a case where the thermostat is simply provided in the holder as one component, components such as a cap in the conventional thermostat can be omitted. Further, the ceramic heater provided on the bottom wall of the holder has a lower surface serving as a surface for fixing the toner by heating and pressurizing the print paper via the fixing film, and an upper surface serving as a surface for detecting the temperature of the bimetal. In this way, temperature detection with high compactness and high thermal response is possible. Furthermore, temperature detection with high thermal responsiveness is possible by bringing the bimetal directly into contact with the heater.

  According to the present invention, a thermostat can be arranged in a fixing machine, and the number of parts is reduced as compared with the case where a conventional thermostat is incorporated, so that a thermostat built-in fixing machine and a laser printer and a copying machine including the fixing machine are provided. It can be provided at low cost. In addition, particularly when a bimetal is provided in direct contact with the upper surface of the ceramic heater, temperature detection with high thermal responsiveness is possible.

  Hereinafter, an embodiment of a thermostat built-in type fixing device of the present invention will be described in more detail with reference to the drawings.

  1 and 2 are longitudinal sectional views of the main part of the thermostat built-in type fixing device according to the first embodiment of the present invention. FIG. 1 shows an initial state in which the switching contacts 11 and 13 are closed. Indicates a state in which the switching contacts 11 and 13 are separated by the reversing operation of the bimetal 19. FIG. 3 is a cross-sectional view in plan view of FIGS. 1 and 2. Further, FIG. 4 is a schematic vertical sectional view in side view showing a use state of the thermostat built-in type fixing device of the present embodiment.

  The thermostat built-in type fixing machine of this embodiment includes a heater 1, a holder 3 for holding the heater 1, a thermostat portion 5 incorporated in the holder 3, and a cylindrical fixing film into which the holder 3 is rotatably inserted. 63 in the main part.

  The thermostat 5 includes a first terminal 7 and a second terminal 9 fixed to the holder 3, a fixed contact 11 provided on the first terminal 7, and a movable contact that contacts or separates from the fixed contact 11. 13 and a movable spring 15 provided on the second terminal 9 for urging the movable contact 13 to the fixed contact 11, and a reversing operation at a set upper limit temperature to move the guide pin 17 upward to move the movable spring. And a bimetal 19 that separates the movable contact 13 from the fixed contact 11 against the urging force of 15.

  The heater 1 of the present embodiment is a ceramic heater and has a rectangular plate shape elongated in the left-right direction. One end of the ceramic heater 1 is provided with two terminals (not shown) for connection to a power source.

  The holder 3 has a substantially U-shaped cross section that opens upward, and its groove extends in the left-right direction. The holder 3 is formed of a material having insulating properties, heat resistance, and thermoplasticity. Specifically, it is made of a thermoplastic resin, and in this embodiment, it is made of liquid crystal plastic.

A plurality of ribs 21 (FIG. 4) are integrally provided at the front and rear end sides of the holder 3 so as to extend upward. In the present embodiment, the ribs 21 are provided at equal intervals in the left-right direction, and are formed at positions corresponding to the front and rear.
The front and rear ends of the holder 3 and the outer surfaces of the ribs 21 formed there are formed in an arc shape that bulges outward in the front-rear direction, and the front and rear ends of the holder 3 constitute a part of the same circle. It is formed to do.

  On the bottom surface of the bottom wall of the holder 3, a shallow U-shaped groove 23 that opens downward is formed in the center in the front-rear direction along the left-right direction. The ceramic heater 1 is fitted into the groove 23 and fixed to the holder 3. In a state where the ceramic heater 1 is fixed to the holder 3, the lower surface of the ceramic heater 1, that is, the heater surface on which the coil pattern is provided, and the lower surface of the holder 3 are flush with each other.

  At least one rectangular through hole is formed in the bottom wall of the rectangular plate of the holder 3, and the upper surface of the ceramic heater 1 is exposed through this through hole. In this embodiment, two through holes are formed, and a temperature sensor (not shown) for monitoring the temperature of the ceramic heater 1 is provided in one through hole (not shown). The other through hole 25 is provided with the bimetal 19 placed on the ceramic heater 1.

  The bimetal 19 may have a disk shape, but is formed in a rectangular shape in this embodiment. Specifically, the bimetal 19 is formed in a rectangular shape curved in a spherical shape. As shown in FIG. 1, the bimetal 19 in the initial state is gently curved downward and convex. When the set upper limit temperature is reached, as shown in FIG.

  The bimetal 19 provided on the bottom wall of the holder 3 is covered with an inner lid 27. The inner lid 27 has a block shape and is formed with a rectangular concave hole 29 opened downward in the center of the lower end surface. In addition, the outer shape of the inner lid 27 is a rectangular shape substantially corresponding to the through hole 25 of the holder 3, and in the state where the inner lid 27 is disposed in the through hole 25, the front / rear and left / right movements are restricted.

  A circular insertion hole 31 penetrating in the vertical direction is formed in the central portion of the inner lid 27. The upper end peripheral edge 31a of the insertion hole 31 is formed in a truncated cone shape so as to protrude slightly upward. Furthermore, upper end edges 33 and 35 at both left and right end portions of the inner lid 27 are formed in a step shape by being cut out in the front-rear direction in a substantially L shape.

  The inner lid 27 is made of heat resistant synthetic resin or ceramic. The inner lid 27 accommodates the bimetal 19 in the recessed hole 29 and is placed in the through hole 25 of the holder 3 while being placed on the ceramic heater 1. The concave hole 29 of the inner lid 27 is formed to be slightly larger than the bimetal 19, and the bimetal 19 can be reversed in the concave hole 29 of the inner lid 27.

  When the inner lid 27 is disposed in the through hole 25 in the bottom wall of the holder 3, the left and right cut-out upper edges 33 and 35 and the upper surface of the adjacent bottom wall are at the same height. .

  A cylindrical guide pin 17 is inserted into the insertion hole 31 of the inner lid 27, and the lower end portion of the guide pin 17 is in contact with the center portion of the bimetal 19. In the initial state, the upper end surface of the guide pin 17 is at the same height as the upper surface of the inner lid 27.

  On the bottom wall of the holder 3 provided with the bimetal 19 and the inner lid 27, a metal rectangular plate-like first terminal 7 and second terminal 9 are placed and fixed. In the present embodiment, the first terminal 7 is provided on the left side of the through hole 25 of the holder 3, and the second terminal 9 is provided on the right side.

  The left end portion 37 of the first terminal 7 and the right end portion 39 of the second terminal 9 are each bent upward in a substantially L shape. Specifically, the left end portion 37 of the first terminal 7 is bent vertically upward and further bent to the left at a right angle and extends horizontally. Further, the right end portion 39 of the second terminal 9 is bent vertically upward, and further bent at a right angle to the right and extends horizontally.

  By the way, a plurality of cylindrical mounting portions 41, 43, 45, 47 are integrally formed on the bottom wall of the holder 3 so as to protrude upward. In this embodiment, the attachment portions 41, 43, 45, 47 are passed through through holes formed in the terminals 7, 9, and the terminals 7, 9 are overlapped with the bottom wall of the holder 3. Then, by applying heat to the tip portions of the mounting portions 41, 43, 45, 47 and being crushed, each terminal 7, 9 is sandwiched between the crushed portion and the bottom wall and fixed to the holder 3. .

  In the present embodiment, the two mounting portions 43 and 41 are respectively passed through the first terminal 7 so as to be separated from each other in the left-right direction, and the tip of one mounting portion 41 is crushed and the first terminal 7 is fixed to the holder 3. Is done. Another mounting portion 43 is used for fixing the cover 53 as described later. Similarly, the attachment portions 45 and 47 are passed through the second terminal 9, and the tip portion of the attachment portion 45 is crushed to fix the second terminal 9 to the holder 3.

  The first terminal 7 is fixed in a state where its right end portion protrudes slightly to the right side from the left edge of the through hole 25 in the bottom wall and is superimposed on the left step portion 33 of the inner lid 27. Furthermore, the second terminal 9 is fixed in a state where the left end portion protrudes slightly to the left side from the right edge of the through hole 25 in the bottom wall and is superimposed on the right step portion 35 of the inner lid 27. As a result, the inner lid 27 is positioned with its upward movement restricted by the right end portion of the first terminal 7 and the left end portion of the second terminal 9.

  A fixed contact 11 is provided on the upper surface of the right end portion of the first terminal 7 so as to protrude upward. In the present embodiment, the fixed contact 11 is formed by protruding the right end portion of the first terminal 7 upward (pushing out and expanding).

  A movable contact 13 is provided so as to be in contact with or separated from the fixed contact 11 provided on the first terminal 7. In the present embodiment, the movable contact 13 is provided on the movable spring 15 made of a long and thin plate spring having conductivity. The movable spring 15 is provided so as to bridge the right end portion of the first terminal 7 and the left end portion of the second terminal 9. A protruding portion 49 is integrally formed at the central portion in the left-right direction of the movable spring 15 so as to protrude downward in a spherical shape.

The movable spring 15 is disposed so that the protruding portion 49 abuts on the center portion of the upper end surface of the guide pin 17, and the right end portion thereof is fixed to the left end portion of the second terminal 9.
In this embodiment, columnar mounting portions 51 and 51 projecting upward at the left end portion of the second terminal 9 are integrally formed at two locations apart from each other in the front and rear directions (FIG. 3). Is passed through the through hole of the movable spring 15, and the upper end portion thereof is caulked to fix the movable spring 15 to the second terminal 9. The movable spring 15 can move up and down at the left end with the right end fixed to the second terminal 9 as a fulcrum.

  The movable contact 13 is provided on the lower surface of the left end portion of the movable spring 15 so as to protrude downward. The movable contact 13 of the present embodiment has a stepped cylindrical shape with a spherical lower surface 13a, and the upper small diameter portion is passed through the hole of the movable spring 15, and then its upper end is caulked to be fixed to the movable spring 15. Is done. The movable contact 13 is always urged downward by a movable spring 15 so as to contact the fixed contact 11 of the first terminal 7. The fixed contact 11 may also be provided on the first terminal 7 with the same configuration as the movable contact 13.

  In the present embodiment, the ceramic heater 1 is energized through the thermostat portion 5. That is, one of the first terminal 7 or the second terminal 9 is connected to the power source, and the other is connected to one terminal of the ceramic heater 1. The other terminal of the ceramic heater 1 is connected to the power source. Specifically, for example, the right end 39 of the second terminal 9 is connected to one terminal of the ceramic heater 1 by a lead wire. Then, the left end portion 37 of the first terminal 7 and the other terminal of the ceramic heater 1 can be connected to the power source, respectively, to form a series of circuits via the switching contacts 11 and 13.

  A cover 53 is covered so as to cover the bimetal 19 and the movable spring 15 provided in the holder 3. The cover 53 has a substantially rectangular shape that opens downward, and the left and right ends thereof are provided on the first terminal 7 and the second terminal 9, respectively. In a state where the cover 53 is attached to the holder 3, the left end portion 37 of the first terminal 7 and the right end portion 39 of the second terminal 9 are disposed outward from the cover 53.

  Through holes 55 and 57 are formed in the left and right ends of the cover 53 along the vertical direction. With the attachment parts 43 and 47 of the holder 3 inserted into the through holes 55 and 57, the cover 53 is Are superimposed on the terminals 7 and 9. And the front-end | tip part of the attaching parts 43 and 47 is crushed by heat, and the cover 53 is fixed to the holder 3 between the bottom wall and the crushed part. In the present embodiment, the through holes 55 and 57 of the cover 53 are stepped holes, and the tip portions of the mounting portions 43 and 47 melted by heat are accommodated in the upper large-diameter holes 55a and 57a. . The cover 53 protects the components of the thermostat portion 5 and can prevent escape of heat.

  As shown in FIG. 4, an elongated metal case 59 having a U-shaped cross section that opens downward is attached to the holder 3 provided with the thermostat portion 5 and the cover 53. The upper wall 61 of the case 59 is formed in an arc shape protruding upward. The case 59 is attached to the holder 3 by inserting both open ends of the case 59 between the ribs 21 and 21 on both sides of the holder 3. In a state in which the case 59 is mounted on the holder 3, the case 59 and the holder 3 are configured in a substantially cylindrical shape having a flat bottom end in a side view.

  The holder 3 to which the case 59 is attached is inserted into the cylindrical fixing film 63. The fixing film 63 is rotatable with respect to the case 59 and the holder 3.

  As described above, the fixed contact 11, the movable contact 13, the movable spring 15, the first terminal 7, and the second terminal 9 are made of a conductive material such as metal. On the other hand, the holder 3, the guide pin 17, the inner lid 27, and the cover 53 are formed of an insulating material such as synthetic resin or ceramic.

  The thermostat built-in fixing device of this embodiment is used by being attached to a laser printer or a copying machine. As shown in FIG. 4, an elongated cylindrical pressure roller 65 is provided in the vicinity of the thermostat built-in type fixing device of the present embodiment, and a paper is interposed between the thermostat built-in type fixing device and the pressure roller 65. (Printing paper) 67 passes. When the paper 67 passes between the thermostat built-in type fixing device and the pressure roller 65, the toner 69A previously attached to the paper 67 is pressurized and the ceramic heater 1 provided in the thermostat built-in type fixing device. The toner 69B is fixed to the paper 67 by being heated and melted by the toner.

In the use state, the thermostat built-in type fixing device of the present embodiment is used in the state shown in FIG. In the initial state, the bimetal 19 is convex downward, the fixed contact 11 and the movable contact 13 are in contact, and the first terminal 7 and the second terminal 9 are electrically connected.
During normal operation, the ceramic heater 1 is turned on and off by a temperature sensor (not shown) to control whether the ceramic heater 1 is energized. When the temperature sensor exceeds the set upper limit temperature due to malfunction or abnormality of the device due to a failure of the temperature sensor for some reason, the thermostat unit 5 operates.

  Specifically, as shown in FIG. 2, the bimetal 19 is inverted upward so that the guide pin 17 is pushed upward. The guide pin 17 pushed upward pushes up the movable spring 15 and the movable contact 13 fixed thereto, and the movable contact 13 leaves the fixed contact 11. Thereby, conduction between the first terminal 7 and the second terminal 9 is interrupted. By the way, by setting the return temperature (setting lower limit temperature) of the bimetal 19 to a normal temperature or lower, once the bimetal 19 is reversely operated, the bimetal 19 maintains the reverse state even if the temperature is lowered to the normal temperature. That is, when the thermostat unit 5 has an abnormality in the device used and becomes high temperature, the bimetal 19 is reversed to stop the power supply to the device and stop the device, and maintain the state at room temperature, Functions as the final safety device against equipment failure.

  The fixing device with a built-in thermostat of this embodiment is provided with the bimetal 19 in direct contact with the ceramic heater 1. Thereby, temperature detection with high heat responsiveness is attained. In addition, since the bimetal 19 is accommodated in the inner lid 27, heat hardly escapes and heat response is good. Furthermore, parts such as a cap and a base can be omitted and the number of parts can be reduced as compared with the case where the thermostat is incorporated into the fixing device as one part.

  FIGS. 5 and 6 are longitudinal cross-sectional views of the main part of the thermostat built-in type fixing device according to the second embodiment of the present invention. FIG. 5 shows an initial state in which the switching contacts 11 and 13 are closed. Indicates a state in which the switching contacts 11 and 13 are separated by the bimetal reversing operation.

  The fixing device with a built-in thermostat of the second embodiment basically has the same configuration as the fixing device with a built-in thermostat of the first embodiment. Therefore, below, it demonstrates centering around a different part of both, and attaches | subjects and demonstrates the same code | symbol to a corresponding location.

  As in the first embodiment, the fixing device with a built-in thermostat of the present embodiment is a ceramic heater 1, a holder 3 that holds the ceramic heater 1, a thermostat portion 5 that is incorporated in the holder 3, and the holder 3 is rotatable. And a fixing film 63 to be inserted into the main portion.

  The thermostat 5 includes a first terminal 7 and a second terminal 9 fixed to the holder 3, a fixed contact 11 fixed to the first terminal 7, and a movable contact that contacts or separates from the fixed contact 11. 13 and a movable spring 15 provided on the second terminal 9 for urging the movable contact 13 to the fixed contact 11, and a reversing operation at a set upper limit temperature, the left end portion (tip portion) 71a thereof is A bimetal 71 that moves upward and separates the movable contact 13 upward from the fixed contact 11 against the urging force of the movable spring 15.

  In the present embodiment, as in the first embodiment, the first terminal 7 and the second terminal 9 are provided on the bottom wall of the holder 3, and the fixed contact 11 is provided on the first terminal 7. The right end of the movable spring 15 is fixed to the second terminal 9, and the movable contact 13 is provided on the lower surface of the left end of the movable spring 15. As in the first embodiment, the movable contact 13 is in contact with the fixed contact 11 by the urging force of the movable spring 15 in the initial state.

  By the way, the left end portion of the second terminal 9 of this embodiment extends from the right edge of the through hole 25 of the holder 3 to the left side, and is then folded back into a U shape from the lower side. And when this 2nd terminal 9 is fixed to the bottom wall of the holder 3, the bimetal 71 is also fixed simultaneously.

  The bimetal 71 of the present embodiment has a rectangular plate shape and is formed in a shape that is curved in a gentle arc shape. The left and right end portions 71a and 71b of the bimetal 71 are formed on a flat surface. The bimetal 71 is disposed in the through hole 25 of the holder 3, and is fixed in a state where a right end portion (base end portion) 71 b that is a flat surface is pressed against the ceramic heater 1 by the second terminal 9.

  That is, when the second terminal 9 is fixed to the bottom wall, the right end portion 71b of the bimetal 71 is disposed between the folded portion 73 and the ceramic heater 1, and the second terminal 9 is connected in the same manner as in the first embodiment. By fixing to the bottom wall, the bimetal 71 is also fixed simultaneously. Accordingly, the base end portion 71 b of the bimetal 71 is fixed in a state of being sandwiched between the folded portion 73 of the second terminal 9 and the ceramic heater 1.

  In this fixed state, the bimetal 71 has a gentle arc shape that protrudes upward while extending obliquely upward as it goes to the left from the fixed flat surface base end portion 71b, and further has a flat surface tip portion. 71a extends obliquely upward to the left. In the initial state, the tip 71 a of the bimetal 71 is disposed slightly below the movable spring 15 so as to be close to the movable spring 15.

  Thus, in the initial state, the bimetal 71 is gently curved in an upwardly convex arc shape as shown in FIG. When the set upper limit temperature is reached, as shown in FIG.

  Further, in this embodiment, an oval contact portion 75 is integrally provided on the lower end surface of the movable spring 15 that is located above the tip end portion 71a of the bimetal 71 so as to protrude downward.

  The use state will be described. The thermostat built-in type fixing device of this embodiment is used in the state shown in FIG. In the initial state, the bimetal 71 is convex upward, the fixed contact 11 and the movable contact 13 are in contact, and the first terminal 7 and the second terminal 9 are electrically connected. The tip 71a of the bimetal 71 is disposed slightly below the movable spring 15 and is not in contact with it.

  When the ceramic heater 1 exceeds the set upper limit temperature due to malfunction or abnormality of the device, the thermostat unit 5 operates. Specifically, as shown in FIG. 6, the bimetal 71 is inverted so as to protrude downward, whereby the tip end portion 71 a of the bimetal 71 moves upward.

  When the tip end portion 71a of the bimetal 71 moves upward, the tip end portion 71a of the bimetal 71 comes into contact with the contact portion 75 of the movable spring 15 and pushes up the movable spring 15 and the movable contact 13 fixed thereto. As a result, the movable contact 13 is separated from the fixed contact 11 and the conduction between the first terminal 7 and the second terminal 9 is interrupted.

  In this embodiment, the base end portion 71b, which is a flat surface of the bimetal 71, is pressed and fixed so as to be in direct contact with the ceramic heater 1, so that the heat transfer to the bimetal 71 is increased and the thermal responsiveness is good. . In addition, the contact between the bimetal 71 and the ceramic heater 1 is strong, and the contact area between the two becomes large and the thermal response is good.

  Next, Embodiment 3 of the thermostat built-in type fixing device of the present invention will be described with a focus on the differences from the above embodiments, and the portions corresponding to the embodiments will be described with the same reference numerals.

  FIGS. 7 and 8 are longitudinal sectional views of the main part of the thermostat built-in type fixing device according to the third embodiment of the present invention. FIG. 7 shows an initial state in which the switching contacts 11 and 13 are closed. Indicates a state in which the switching contacts 11 and 13 are separated by the reversing operation of the trimetal 81.

  The fixing device with a built-in thermostat of the present embodiment is similar to the above-described embodiments in that the ceramic heater 1, the holder 3 holding the ceramic heater 1, the thermostat portion 5 incorporated in the holder 3, and the holder 3 are rotated. A fixing film 63 that can be inserted is provided in the main part.

  The thermostat portion 5 of the present embodiment includes a first terminal 7 and a second terminal 9 fixed to the holder 3, a fixed contact 11 fixed to the first terminal 7, and a contact or A movable contact 13 that is separated from the fixed contact 11 and a trimetal 81 that separates the movable contact 13 from the fixed contact 11 by urging the movable contact 13 to the fixed contact 11 and performing a reverse operation at a set upper limit temperature are provided. The trimetal 81 has a three-layer structure in which a metal piece having high electrical conductivity is provided between two metal pieces having different thermal expansion coefficients, and has a structure that generates little heat due to energization. That is, it can be said that the bimetal has a high conductivity.

The first terminal 7 and the second terminal 9 are provided on the bottom wall of the holder 3 as in the above embodiments, and the fixed contact 11 is provided on the first terminal 7.
The first terminal 7 of this embodiment has its right end bent vertically upward and then bent further to the right to extend horizontally. In the present embodiment, the fixed contact 11 is provided at the lower end of the horizontal piece 83. Further, the left end portion of the second terminal 9 is folded back in a U-shape from the lower side as in the second embodiment.

  In the first and second embodiments described above, the movable contact 13 is provided on the movable spring 15, and the movable contact 13 and the fixed contact 11 are in contact with each other by the biasing force of the movable spring 15 in the initial state. On the other hand, in the thermostat built-in type fixing machine according to the third embodiment, the movable contact 13 is provided on the trimetal 81, and the movable contact 13 is in contact with the fixed contact 11 in the initial state.

  The trimetal 81 of the present embodiment has a rectangular plate shape, and is formed in a shape that is gently curved in an arc shape. The left and right end portions 81a and 81b of the trimetal 81 are formed on a flat surface. In this embodiment, the movable contact 13 is provided on the upper surface of the left end portion 81a of the trimetal 81 so as to protrude upward. The movable contact 13 of this embodiment has a stepped cylindrical shape with an upper surface 13a and a lower small diameter portion passed through a hole in the trimetal 81, and then its lower end portion is caulked to be fixed to the trimetal 81. .

  The trimetal 81 is disposed in the through hole 25 of the holder 3 and is fixed in a state where a right end portion (base end portion) 81 b which is a flat surface is pressed against the ceramic heater 1 by the second terminal 9.

  That is, when the second terminal 9 is fixed to the bottom wall, the base end portion 81b of the trimetal 81 is disposed between the folded portion 73 and the ceramic heater 1, and the second terminal 9 is the same as in the first embodiment. By fixing to the bottom wall, the trimetal 81 is also fixed simultaneously. Thereby, the base end portion 81 b of the trimetal 81 is fixed in a state of being sandwiched between the folded portion 73 of the second terminal 9 and the ceramic heater 1.

  In this fixed state, the trimetal 81 has a gentle arc shape that protrudes downward while extending obliquely upward as it goes to the left side from the fixed flat surface-shaped base end portion 81b, and further has a flat surface-shaped distal end portion. 81a extends obliquely upward to the left.

  Thus, in the initial state, the trimetal 81 of the present embodiment is gently curved in a downwardly convex arc shape as shown in FIG. In this initial state, the movable contact 13 is in contact with the fixed contact 11 by the urging force of the trimetal 81. Then, when the set upper limit temperature is reached, the trimetal 81 reverses into a convex upward state as shown in FIG.

The usage state will be described. The thermostat built-in type fixing device of the third embodiment is used in the state shown in FIG. In the initial state, the trimetal 81 is convex downward, the fixed contact 11 and the movable contact 13 are in contact, and the first terminal 7 and the second terminal 9 are electrically connected.
When the set upper limit temperature is exceeded due to a malfunction of the temperature sensor or malfunction or abnormality of the device, the thermostat unit 5 operates.

  Specifically, as shown in FIG. 8, the trimetal 81 is inverted so as to protrude upward, whereby the tip end portion 81 a of the trimetal 81 moves downward. When the tip 81 a of the trimetal 81 moves downward, the movable contact 13 provided on the trimetal 81 also moves downward, and the movable contact 13 moves away from the fixed contact 11. Thereby, conduction between the first terminal 7 and the second terminal 9 is interrupted.

  In this embodiment, the base end portion 81b, which is a flat surface of the trimetal 81, is pressed and fixed so as to be in direct contact with the ceramic heater 1, so that the heat transfer to the trimetal 81 is increased and the thermal responsiveness is increased. Good. Further, the contact area between the trimetal 81 and the ceramic heater 1 is increased, and the thermal response is good.

  Next, a fourth embodiment of the thermostat built-in fixing device according to the present invention will be described with a focus on differences from the respective embodiments, and portions corresponding to the respective embodiments will be described with the same reference numerals.

  FIGS. 9 and 10 are longitudinal sectional views of the main part of the thermostat built-in type fixing device according to the fourth embodiment of the present invention. FIG. 9 shows an initial state in which the switching contacts 11 and 13 are closed. Indicates a state in which the switching contacts 11 and 13 are separated by the reversing operation of the bimetal 99.

  The fixing device with a built-in thermostat of the present embodiment is similar to the above-described embodiments in that the ceramic heater 1, the holder 3 that holds the ceramic heater 1, the thermostat portion 5 that is incorporated in the holder 3, and the holder 3 A cylindrical fixing film 63 that is rotatably inserted is provided in the main part.

  The thermostat 5 includes a first terminal 7 and a second terminal 9 fixed to the holder 3, a fixed contact 11 fixed to the first terminal 7, and a movable contact that contacts or separates from the fixed contact 11. 13 and a movable spring 15 provided on the second terminal 9 for urging the movable contact 13 to the fixed contact 11, and a reversing operation at a set upper limit temperature. A bimetal 99 that moves upward and separates the movable contact 13 upward from the fixed contact 11 against the urging force of the movable spring 15.

  In each of the above embodiments, the bimetal 19 or 71 or the trimetal 81 is provided in the through hole 25 formed in the bottom wall of the holder 3. The bimetal 99 is disposed in the open cavity (recesses 91 and 93).

  Specifically, a rectangular first recess 91 is formed on the lower surface of the bottom wall of the holder 3 of the present embodiment so as to be recessed upward. Further, a second recess 93 is formed continuously from the first recess 91 at the center in the left-right direction of the first recess 91 so as to be further recessed upward. Thus, the 1st recessed part 91 and the 2nd recessed part 93 which open below are continuously formed in the bottom wall lower surface of the holder 3 of a present Example.

  In the present embodiment, the metal rectangular plate-like first terminal 7 and second terminal 9 are fixed along the upper surface of the first recess 91. That is, the first terminal 7 and the second terminal 9 are overlapped and fixed on the upper surface of the first recess 91.

  In the present embodiment, the first terminal 7 is provided on the left side of the second recess 93 and the second terminal 9 is provided on the right side. At this time, the first terminal 7 is fixed with its right end portion extending from the left edge of the second recess 93 to the right side. The second terminal 9 is fixed in a state in which the left end portion extends from the right edge of the second recess 93 to the left side.

  On the upper surface of the first recess 91 of the holder 3, a plurality of columnar attachment portions 95, 95 are integrally formed so as to protrude downward. In the present embodiment, the attachment portions 95 and 95 are passed through through holes formed in the terminals 7 and 9, and the terminals 7 and 9 are overlapped with the upper surface of the first recess 91. Then, by applying heat to the tip portions of the attachment portions 95 and 95 and crushed, the terminals 7 and 9 are sandwiched between the crushed portion and the upper surface of the first recess 91 and fixed to the holder 3. .

  A fixed contact 11 is provided on the upper surface of the right end portion of the first terminal 7 so as to protrude upward as in the above embodiments. In the present embodiment, the fixed contact 11 is provided on the upper surface of the right end portion of the first terminal 7 extending into the second recess 93.

  A movable contact 13 is provided so as to be in contact with or separated from the fixed contact 11 provided on the first terminal 7. In the present embodiment, as in the first embodiment, the movable contact 13 is provided on the movable spring 15 made of an elongated leaf spring having conductivity. The movable spring 15 is provided so as to bridge the right end portion of the first terminal 7 and the left end portion of the second terminal 9.

  The right end of the movable spring 15 of this embodiment is fixed to the left end of the second terminal 9 extending into the second recess 93 in the same manner as in the first embodiment. The movable spring 15 can move up and down at the left end with the right end fixed to the second terminal 9 as a fulcrum in the second recess 93.

  Similar to the first embodiment, the movable contact 13 is provided on the lower surface of the left end portion of the movable spring 15 so as to protrude downward. The movable contact 13 is always urged downward by a movable spring 15 so as to contact the fixed contact 11 of the first terminal 7.

  A substantially U-shaped thin metal plate 97 is provided below the left end of the second terminal 9. In this embodiment, a U-shaped leaf spring 97 that opens to the left is provided. The bimetal 99 of this embodiment is fixed in a state where it is pressed against the ceramic heater 1 by the leaf spring 97.

  The bimetal 99 of the present embodiment has a rectangular plate shape, and is formed in a shape curved in a gentle arc shape. The left and right end portions 99a and 99b of the bimetal 99 are formed on a flat surface. The bimetal 99 is disposed in a hollow portion made up of the first concave portion 91 and the second concave portion 93 of the holder 3, and the right end portion (base end portion) 99 b that is a flat surface is pressed against the ceramic heater 1 by the leaf spring 97. Fixed in state.

  That is, the bimetal 99 is fixed by disposing the right end portion 99 b between the leaf spring 97 and the ceramic heater 1. Thus, the bimetal 99 is fixed in a state where the base end portion 99 b is sandwiched between the leaf spring 97 and the ceramic heater 1.

  In this fixed state, the bimetal 99 has a gentle arc shape that protrudes upward while extending obliquely upward as it goes to the left side from the fixed flat surface-shaped base end portion 99b, and further has a flat surface-shaped distal end portion. 99a extends obliquely upward to the left. In the initial state, the tip 99 a of the bimetal 99 is disposed slightly below the movable spring 15 so as to be close to the movable spring 15.

  Thus, in the initial state, the bimetal 99 is gently curved in an upwardly convex arc shape as shown in FIG. When the set upper limit temperature is reached, as shown in FIG.

  In the bottom wall of the holder 3, through holes 101 and 103 that open into the first recess 91 along the vertical direction are formed on the left and right sides of the second recess 93, respectively. Each upper surface of the two terminals 9 is exposed. The lead wires 105 and 107 are connected to the first terminal 7 and the second terminal 9 through the through holes 101 and 103, respectively. As a result, the ceramic heater 1 is energized via the thermostat 5 as in the above embodiments.

  The use state will be described. The thermostat built-in type fixing device of this embodiment is used in the state shown in FIG. In the initial state, the bimetal 99 is convex upward, the fixed contact 11 and the movable contact 13 are in contact, and the first terminal 7 and the second terminal 9 are electrically connected. The tip 99a of the bimetal 99 is disposed slightly below the movable spring 15 and is not in contact with it.

  When the ceramic heater 1 exceeds the set upper limit temperature due to malfunction or abnormality of the device, the thermostat unit 5 operates. Specifically, as shown in FIG. 10, the bimetal 99 is inverted so as to protrude downward, whereby the tip 99 a of the bimetal 99 moves upward.

  When the tip 99a of the bimetal 99 moves upward, the tip 99a of the bimetal 99 comes into contact with the movable spring 15 and pushes up the movable spring 15 and the movable contact 13 fixed thereto. As a result, the movable contact 13 is separated from the fixed contact 11 and the conduction between the first terminal 7 and the second terminal 9 is interrupted.

  By the way, in the thermostat built-in type fixing machine of this embodiment, after the first terminal 7, the second terminal 9, the movable spring 15, the leaf spring 97, the bimetal 99 and the like are attached to the holder 3, the ceramic is placed in the groove 23 of the holder 3. A heater 1 is attached. Therefore, the bimetal 99 is fixed in a state of being pressed against the ceramic heater 1 by the leaf spring 97.

In this embodiment, the base end portion 99b, which is a flat surface of the bimetal 99, is pressed and fixed so as to be in direct contact with the ceramic heater 1, so that the contact between the bimetal 99 and the ceramic heater 1 is strong and The contact area between the two becomes large and the thermal response is good.
Further, compared to the case where the thermostat is incorporated into the fixing device as one component, components such as a cap and a base can be omitted, and the number of components can be reduced.

  Next, a fifth embodiment of the thermostat built-in fixing device of the present invention will be described.

  The fixing device with a built-in thermostat according to the fifth embodiment basically has the same configuration as the fixing device with a built-in thermostat according to the fourth embodiment. Therefore, below, it demonstrates centering around a different part of both, and attaches | subjects and demonstrates the same code | symbol to a corresponding location.

  FIGS. 11 and 12 are longitudinal cross-sectional views of the main part showing the fifth embodiment of the thermostat built-in type fixing device of the present invention. FIG. 11 shows an initial state in which the switching contacts 11 and 13 are closed. Indicates a state in which the switching contacts 11 and 13 are separated by the reversing operation of the bimetal 99.

  In the bottom wall of the holder 3 of the present embodiment, a third recess 111 is formed at the lower end of the first recess 91 and further widened outward in the left-right direction. The third recess 111 is provided with a rectangular plate-shaped metal cover 113. The cover 113 of this embodiment is disposed in the third recess 111 in a state where the cover 113 is in contact with the ceramic heater 1.

  The bimetal 99 of the present embodiment is fixed in a state where the base end portion 99 b is sandwiched between the cover 113 and the leaf spring 97. Further, in this embodiment, a part of the cover 113 is formed to be curved upward in a substantially semicircular shape, and when the bimetal 99 is inverted, the bimetal 99 is in contact with the curved portion 115. Yes.

  The use state will be described. The thermostat built-in type fixing device of this embodiment is used in the state shown in FIG. In the initial state, the bimetal 99 is convex upward, the fixed contact 11 and the movable contact 13 are in contact, and the first terminal 7 and the second terminal 9 are electrically connected. The tip 99a of the bimetal 99 is disposed slightly below the movable spring 15 and is not in contact with it.

  When the ceramic heater 1 exceeds the set upper limit temperature due to malfunction or abnormality of the device, the thermostat unit 5 operates. Specifically, as shown in FIG. 12, the bimetal 99 is inverted so as to protrude downward, whereby the tip 99 a of the bimetal 99 moves upward.

  When the tip 99a of the bimetal 99 moves upward, the tip 99a of the bimetal 99 comes into contact with the movable spring 15 and pushes up the movable spring 15 and the movable contact 13 fixed thereto. As a result, the movable contact 13 is separated from the fixed contact 11 and the conduction between the first terminal 7 and the second terminal 9 is interrupted.

  In the present embodiment, as shown in FIG. 12, when the bimetal 99 is reversed, the bimetal 99 comes into contact with the curved portion 115 of the cover 113, thereby increasing the inclination angle of the bimetal 99. That is, compared with the case of Example 4 which does not contact | abut the curved part 115 of the cover 113, the bimetal 99 can be further flipped up and the movable contact 13 and the fixed contact 11 are spaced apart reliably.

  By the way, in the thermostat built-in type fixing machine of the present embodiment, the first terminal 7, the second terminal 9, the movable spring 15, the leaf spring 97, the bimetal 99 and the like are attached to the holder 3 as in the fifth embodiment. After the one recess 91 and the second recess 93 are closed by the cover 113, the ceramic heater 1 is attached to the groove 23 of the holder 3. Therefore, the bimetal 99 is fixed while being pressed against the cover 113 by the leaf spring 97.

In this embodiment, the base end portion 99b, which is a flat surface of the bimetal 99, is pressed against the ceramic heater 1 through the metal cover 113, so that the thermal response is good.
Further, since the cover 113 is provided so as to cover the first concave portion 91 and the second concave portion 93 of the holder 3, it is possible to prevent dust and dust from entering the thermostat portion 5 during assembly. .
Furthermore, according to the fixing device with a built-in thermostat of the present embodiment, parts such as a cap and a base can be omitted and the number of parts can be reduced as compared with the case where the thermostat is incorporated into the fixing machine as one part.

  Next, a sixth embodiment of the thermostat built-in fixing device of the present invention will be described.

  The fixing device with a built-in thermostat according to the sixth embodiment has basically the same configuration as the fixing device with a built-in thermostat according to the fourth and fifth embodiments. Therefore, in the following, different parts will be mainly described, and corresponding portions will be described with the same reference numerals.

  FIGS. 13 and 14 are longitudinal sectional views of the main part showing a sixth embodiment of the thermostat built-in type fixing device of the present invention. FIG. 13 shows an initial state in which the switching contacts 11 and 13 are closed. Indicates a state in which the switching contacts 11 and 13 are separated by the reversing operation of the bimetal 121.

  The bimetal 121 of the present embodiment has a rectangular plate shape and is formed in a shape that is curved in a gentle arc shape. The bimetal 121 of this embodiment is fixed in a state where the right end portion (base end portion) 121 b is disposed between the movable spring 15 and the second terminal 9.

  That is, when the movable spring 15 is fixed to the second terminal 9, the right end portion 121 b of the bimetal 121 is disposed and fixed between the movable spring 15 and the second terminal 9. Thus, the bimetal 121 of the present embodiment is fixed in a state in which the base end portion 121 b is sandwiched between the movable spring 15 and the second terminal 9.

  In this fixed state, the bimetal 121 is formed in a gentle arc shape that protrudes upward while extending obliquely downward as it goes to the left from the fixed base end part 121b. In the initial state, the tip 121 a of the bimetal 121 is disposed slightly below the movable spring 15.

  Thus, in the initial state, the bimetal 121 is gently curved in an upwardly convex arc shape as shown in FIG. Then, when the set upper limit temperature is reached, as shown in FIG.

  In this embodiment, a rectangular sheet-like resin film 123 is provided in the third recess 111 of the bottom wall of the holder 3. The film 123 of the present embodiment is provided in the third recess 111 so as to contact the ceramic heater 1.

  The usage state will be described. The thermostat built-in type fixing device of this embodiment is used in the state shown in FIG. In the initial state, the bimetal 121 is convex upward, the fixed contact 11 and the movable contact 13 are in contact, and the first terminal 7 and the second terminal 9 are electrically connected. The tip 121a of the bimetal 121 is disposed slightly below the movable spring 15 and is not in contact with it.

  When the ceramic heater 1 exceeds the set upper limit temperature due to malfunction or abnormality of the device, the thermostat unit 5 operates. Specifically, as shown in FIG. 14, the bimetal 121 is inverted so as to protrude downward, whereby the tip 121 a of the bimetal 121 moves upward.

  When the tip 121a of the bimetal 121 moves upward, the tip 121a of the bimetal 121 comes into contact with the movable spring 15 and pushes up the movable spring 15 and the movable contact 13 fixed thereto. As a result, the movable contact 13 is separated from the fixed contact 11 and the conduction between the first terminal 7 and the second terminal 9 is interrupted.

  By the way, in the thermostat built-in type fixing machine of the present embodiment, the first terminal 7, the second terminal 9, the movable spring 15, the bimetal 121, and the like are attached to the holder 3 as in the fifth embodiment, and the first recess and After the second recess is closed with the film 123, the ceramic heater 1 is attached to the groove 23 of the holder 3. Since the first concave portion 91 and the second concave portion 93 are closed by the film 123, it is possible to prevent entry of dust, dust and the like into the thermostat portion 5 during assembly.

  According to the fourth to sixth embodiments, the hollow portion formed of the first concave portion 91 and the second concave portion 93 of the holder 3 is closed by the ceramic heater 1, the cover 113, or the film 123, so that heat is difficult to escape and a thermal response. Good sex.

  As described above, according to the present invention, the thermostat can be incorporated in the fixing device, and the number of parts can be reduced. Moreover, thermal responsiveness can be improved by using a rectangular bimetal.

The fixing device with a built-in thermostat of the present invention is not limited to the configuration of each of the embodiments described above, and can be changed as appropriate. In particular, as long as the configuration is such that the bimetal or trimetal is brought into direct contact with the ceramic heater, and the fixed contact and the movable contact that are in contact with each other by the reversing operation (snap operation) are separated, the configuration is not limited to the configuration of each of the above embodiments, and changes are made as appropriate. Is possible.
In the third embodiment, the fixed contact 11 protrudes downward from the first terminal 7. However, the fixed contact 11 protrudes upward as in the first embodiment, and protrudes downward to the left end of the trimetal 81. Alternatively, the movable contact 13 may be provided so that the movable contact 13 contacts the fixed contact 11 from above. In this case, in the initial state, the trimetal 81 is projected upward, the movable contact 13 and the fixed contact 11 are kept in contact, and when the ceramic heater 1 exceeds the set upper limit temperature, it is inverted downward to the convex state. The movable contact 13 and the fixed contact 11 may be separated.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a longitudinal sectional view of a main part of a thermostat built-in fixing device according to a first embodiment of the present invention, showing an initial state in which a switching contact is closed. FIG. 2 shows a state in which the switching contact is separated from the state of FIG. 1 by the bimetal reversing operation. FIG. 3 is a cross-sectional view in plan view of FIGS. 1 and 2. FIG. 2 is a schematic vertical sectional view in side view showing a usage state of the thermostat built-in type fixing device of FIG. 1. It is a front view longitudinal cross-sectional view which shows the main part which shows Example 2 of the thermostat built-in type fixing machine of this invention, and has shown the initial state which the switching contact closed. FIG. 6 shows a state in which the switching contact is separated from the state of FIG. 5 by the bimetal reversing operation. It is a front view longitudinal cross-sectional view of the principal part which shows Example 3 of the thermostat built-in type fixing device of this invention, and has shown the initial state which the switching contact closed. FIG. 8 shows a state in which the switching contact is separated from the state of FIG. 7 by the trimetal reversing operation. It is a front view longitudinal cross-sectional view which shows the main part which shows Example 4 of the thermostat built-in type fixing machine of this invention, and has shown the initial state which the switching contact closed. FIG. 10 shows a state in which the switching contact is separated from the state of FIG. 9 by the bimetal reversing operation. It is a front view longitudinal cross-sectional view which shows the main part which shows Example 5 of the thermostat built-in type fixing machine of this invention, and has shown the initial state which the switching contact closed. FIG. 11 shows a state in which the switching contact is opened by the bimetal reversing operation from the state of FIG. It is a front view longitudinal cross-sectional view which shows the Example 6 of the thermostat built-in type fixing machine of this invention, and has shown the initial state which the switching contact closed. FIG. 14 shows a state in which the switching contact is separated from the state of FIG. 13 by the bimetal reversing operation.

Explanation of symbols

1 Heater 3 Holder 5 Thermostat 7 First Terminal 9 Second Terminal 11 Fixed Contact (Open / Close Contact)
13 Movable contact (open / close contact)
15 Movable spring 17 Guide pin 19 Bimetal 25 Through hole (opening)
27 Inner lid 53 Cover 59 Case 63 Fixing film 65 Pressure roller 71 Bimetal 81 Trimetal 91 First recess 93 Second recess 99 Bimetal 113 Cover 121 Bimetal 123 Film

Claims (12)

A holder having a heater on the lower surface of the bottom wall, and a cylindrical fixing film into which the holder is inserted and accommodated,
The fixing device with a built-in thermostat, wherein the holder is a case of a thermostat having an open / close contact that cuts off power to the heater in accordance with a bimetal snap operation. The thermostat built-in fixing device according to claim 1, wherein a ceramic heater as the heater is overlapped and fixed to a lower surface of a bottom wall of the holder made of synthetic resin. The bottom wall has a substantially rectangular plate-like bottom wall on the left and right, and ribs are formed extending upward and downward on both sides of the bottom wall, and an opening is formed through the bottom wall in the vertical direction. With a holder,
A substantially rectangular plate-shaped ceramic heater fixed to the bottom surface of the bottom wall of the holder;
A bimetal disposed in the opening of the holder and provided in direct contact with the upper surface of the ceramic heater exposed from the opening;
In accordance with the bimetal snap operation, an open / close contact that cuts off power to the ceramic heater,
A thermostat built-in type fixing machine comprising: a cylindrical fixing film in which the holder with the ceramic heater is inserted and received. The bimetal is disposed in an opening formed through the bottom wall of the holder, is in contact with the upper surface of the ceramic heater in a convex state, and reverses upward in a convex state when reaching a set temperature. And
The open / close contact consists of a fixed contact fixed to the upper surface of the bottom wall of the holder, and a movable contact that is biased downward by a leaf spring to contact the upper surface of the fixed contact,
4. The thermostat built-in fixing device according to claim 2, wherein a guide pin that pushes up the leaf spring based on a reversing operation of the bimetal is disposed below the leaf spring so as to be movable up and down. 5. . The bimetal is disposed in an opening formed through the bottom wall of the holder, the base end is fixed in contact with the upper surface of the ceramic heater, and the tip is moved upward when the set temperature is reached. It is configured to reverse operation like
The open / close contact is urged downward by a fixed spring fixed to the upper surface of the bottom wall of the holder and a plate spring so as to contact the upper surface of the fixed contact. The thermostat built-in type fixing device according to claim 2, further comprising a movable contact that is pushed up to move away from the fixed contact. The bimetal is disposed in an opening formed through the bottom wall of the holder, the base end is fixed in contact with the upper surface of the ceramic heater, and the tip is moved downward when the set temperature is reached. It is composed of trimetal that reverses like
The open / close contact is provided at a fixed contact fixed downward on the upper surface of the bottom wall of the holder and a tip of the trimetal, and is biased upward so as to contact the lower surface of the fixed contact. The fixing device with a built-in thermostat according to claim 2, further comprising a movable contact that moves downward from the fixed contact based on a reversing operation. The bimetal is formed in a substantially rectangular shape,
The thermostat built-in fixing device according to any one of claims 4 to 6, wherein the bimetal, the fixed contact, and the movable contact are covered with a cover fixed to the holder. A holder having an elongated rectangular plate-like bottom wall on the left and right, extending upward on both front and rear side edges of the bottom wall, and a recess formed in the bottom wall opening downward;
A substantially rectangular plate-shaped ceramic heater fixed to the bottom surface of the bottom wall of the holder;
A bimetal disposed in the recess of the holder;
In accordance with the bimetal snap operation, an open / close contact that cuts off power to the ceramic heater,
A thermostat built-in type fixing machine comprising: a cylindrical fixing film in which the holder with the ceramic heater is inserted and received. The bimetal is disposed in a recess formed in the bottom wall of the holder so as to open downward, and the base end is fixed in direct contact with the upper surface of the ceramic heater. Is configured to reverse so as to move upward,
The open / close contact is urged downward by a fixed contact fixed to the bottom wall of the holder and a plate spring so as to contact the upper surface of the fixed contact, and the plate spring is pushed up based on the reversing operation of the bimetal. The thermostat built-in fixing device according to claim 2, wherein the fixing device includes a movable contact that is separated from the fixed contact. The bimetal is disposed in a recess formed by opening downward in the bottom wall of the holder, and a base end portion is fixed in contact with the upper surface of the ceramic heater through a metal plate that closes the recess. And when the set temperature is reached, the tip part is configured to reverse so as to move upward,
The open / close contact is urged downward by a fixed contact fixed to the bottom wall of the holder and a plate spring so as to contact the upper surface of the fixed contact, and the plate spring is pushed up based on the reversing operation of the bimetal. The thermostat built-in fixing device according to claim 2, wherein the fixing device includes a movable contact that is separated from the fixed contact. The bimetal is arranged in a recess formed in the bottom wall of the holder so as to open downward, and when the set temperature is reached, the bimetal is reversed to move upward,
The lower end of the recess is closed by a film,
The open / close contact is urged downward by a fixed contact fixed to the bottom wall of the holder and a plate spring so as to contact the upper surface of the fixed contact, and the plate spring is pushed up based on the reversing operation of the bimetal. The thermostat built-in fixing device according to claim 2, wherein the fixing device includes a movable contact that is separated from the fixed contact. A thermostat built-in type fixing device according to any one of claims 1 to 11,
A pressure roller that is rotatably provided with a print sheet interposed between the thermostat-incorporating type fixing device and that heats the ceramic sheet through the fixing film to fix the toner on the print sheet. A laser printer or a copying machine, comprising:

Images