JP5754223B2 - Fixing device - Google Patents

Description

  The present invention relates to a fixing device used in an image forming apparatus such as a copying machine, and more particularly to a fixing device capable of measuring the temperature of a fixing roller or a fixing belt with high accuracy.

  Generally, an image forming apparatus such as a copying machine, a printer, a facsimile machine, or a printing machine has a built-in fixing device that forms image information as a toner image on a recording paper, heats it, and transfers it. The fixing device includes a heated fixing roller or a fixing belt and a pressure roller pressed against the fixing roller, and a fixing nip is formed at a pressure contact portion between the fixing roller or the fixing belt and the pressure roller to fix the fixing roller. When passing through the nip, pressure and heat are applied to the recording paper to fix the toner image. At this time, since it is necessary to control the temperature of the fixing roller and the fixing belt for fixing the toner image by heating, the surface temperature is detected using a temperature sensor.

  Conventionally, for example, Patent Document 1 includes temperature detection means for measuring the surface temperature of a heat generating rotating body heated by an induction heating unit, and the temperature detection unit is provided on the inner peripheral side of a coil loop provided in the induction heating unit. There has been proposed a fixing device that detects the surface temperature of a heat-generating rotating body through a hole formed therein. This temperature detecting means includes a thermopile element that is a non-contact type temperature sensor and a condenser lens, and is fixed to the housing via a support member in order to separate the thermopile element having a low heat-resistant temperature from the heat source. Further, since the temperature fluctuation is severe in the vicinity of the fixing roller, a structure is used in which the focal point is focused with a condenser lens away from the fixing roller.

  Patent Document 2 discloses a temperature sensor that measures the temperature of a heat fixing roller or the like used in a fixing device of a copying machine, and includes a resin film installed on a holder and a holder provided on the resin film. There has been proposed an infrared sensor including an infrared detection thermal element that detects infrared rays through a light guide portion and a temperature compensation thermal element that is provided in a light-shielding state on a resin film and detects the temperature of a holding body. In this infrared sensor, an infrared absorption film is formed on the inner side surface of the light guide section, and an infrared absorption material such as carbon black is included in the resin film to enhance infrared absorption. Further, in this infrared sensor, a heat sensitive element is built in a holding body which is a casing formed in a substantially block shape from a metal material having a high thermal conductivity such as aluminum and a low thermal emissivity.

JP 2009-271129 A JP 2002-156284 A

The following problems remain in the conventional technology.
In the fixing device described in Patent Document 1, a long distance (space) is required between the temperature sensor and the fixing device in order to thermally isolate the temperature sensor from the fixing roller. In addition, a support member for attaching a temperature sensor to form an integral structure needs to have a structure in which the cross-sectional area is reduced by thinning or thinning it in order to reduce heat conduction. For example, the infrared viewing angle is shifted and it is difficult to measure with high accuracy. In addition, the thermopile is difficult to detect temperature with high accuracy because the element is sealed with gas and is insensitive to ambient temperature fluctuations. Furthermore, in the infrared temperature sensor described in Patent Document 2, since the structure is greatly different between the detection side and the compensation side, a large difference occurs in the heat capacity, resulting in a temperature distribution, so that a high-accuracy temperature measurement cannot be performed. was there.

Further, in the infrared sensor of Patent Document 2, a structure in which an infrared absorbing material such as carbon black is contained in a resin film and one heat sensitive element side is shielded for temperature compensation is used, but the infrared absorbing material is included. The heat conduction of the resin film is high, and there is a disadvantage that a temperature difference is hardly generated between the heat sensing elements for infrared detection and temperature compensation. Also, in order to increase the temperature difference between these thermal elements, it is necessary to increase the distance between the thermal elements, which increases the overall shape and makes it difficult to reduce the size. Furthermore, since it is necessary to provide the case itself with a structure that shields the temperature-compensating thermal element, the cost is increased.
In addition, the heat-sensitive element has a structure that shields infrared rays with a housing, but the shielding part absorbs infrared rays only by shielding the infrared rays, and the temperature of the shielding part changes. There was an inconvenience of being incomplete as a reference.

  The present invention has been made in view of the above-mentioned problems, and it is not necessary to isolate the heat from the fixing roller or the fixing belt, and the temperature of the fixing roller or the fixing belt can be accurately adjusted even if the amount of heat received by the temperature sensor is large. Another object of the present invention is to provide a fixing device including an infrared sensor that can be detected.

  The present invention employs the following configuration in order to solve the above problems. That is, the fixing device of the first invention generates heat in the fixing roller or the fixing belt, the pressure roller that forms a fixing nip between the fixing roller or the fixing belt, and the fixing roller and the fixing belt. A fixing device comprising a heating mechanism for holding the housing and a housing for holding them inside, and comprising an infrared sensor for detecting temperature by receiving infrared rays from the fixing roller or the fixing belt, An insulating film, a first heat sensitive element and a second heat sensitive element provided on one surface of the insulating film, and the first heat sensitive element formed on one surface of the insulating film. A conductive first wiring film connected to the element, a conductive second wiring film connected to the second thermal element, and the insulating film facing the second thermal element. And an infrared reflecting film provided on the surface of the insulating film, and the other surface of the insulating film is opposed to the outer surface of the fixing roller or the fixing belt or the inner surface of the fixing belt. It is characterized by.

  In this fixing device, an infrared sensor installed in the casing is provided on the first and second thermal elements provided on one surface of the insulating film so as to be separated from each other, and the second thermal element. And an infrared reflection film provided on the other surface of the insulating film so as to face each other, so that a first heat sensing element for detection and a second heat sensitive element for compensation are arranged on the insulating film. The temperature distribution that occurs in is reduced. For this reason, both heat sensitive elements on the insulating film are simultaneously affected and sensitively affected by temperature fluctuations due to heat from the fixing roller or fixing belt, so that the radiant heat from the fixing roller or fixing belt is detected with high accuracy. be able to. Therefore, even if the amount of heat received by the infrared sensor is large, the temperature of the fixing roller or the fixing belt can be detected in a non-contact manner with high accuracy, and there is a need for a space and a support structure for heat isolation from the fixing roller or the fixing belt. It can be installed in the housing in a small space, and the whole can be reduced in size and cost.

In addition, since the said infrared sensor is equipped with the infrared reflective film provided in the other surface of the insulating film facing the 2nd thermal element, the 1st thermal element was irradiated with infrared rays and absorbed infrared rays. In contrast to measuring the partial temperature of the insulating film, the second thermosensitive element measures the partial temperature of the insulating film in which the infrared ray is reflected by the infrared reflecting film and the infrared absorption is greatly suppressed. Therefore, the first heat sensitive element is formed by the second heat sensitive element under the infrared reflecting film that can suppress the influence of infrared rays on the first heat sensitive element and obtain a high reference, and the thin insulating film having low thermal conductivity. A good temperature difference between the element and the second thermosensitive element can be obtained.
That is, even in a low thermal conductive insulating film that does not contain an infrared absorbing material or the like in the film, the infrared reflecting film can reflect the infrared rays directly above the second heat sensitive element to prevent the absorption. A temperature difference from the first thermosensitive element directly under the portion that does not reflect the light is obtained, and the second thermosensitive element can be used as a high reference.
Moreover, the medium which conducts the heat between the first heat sensitive element and the second heat sensitive element is only an insulating film other than air, and the conducting cross-sectional area is reduced. Accordingly, it is difficult for heat to be transmitted to the mutual heat sensitive elements, interference is reduced, and detection sensitivity is improved. As described above, since the thermal coupling between the first thermal element and the second thermal element is low, it is possible to arrange them close to each other, and the overall size can be reduced. Furthermore, since the infrared rays are shielded by the infrared reflecting film rather than the light shielding structure by the frame or the case, it can be manufactured at low cost.
Furthermore, even if the infrared reflective film is made of a conductive material, insulation between the first and second heat sensitive elements installed with the insulating film interposed therebetween is ensured, so that the insulating properties of the film It is possible to select an efficient material regardless of whether or not.
As described above, the first heat sensitive element and the second heat sensitive element in which the influence of heat on the low heat conductive insulating film is suppressed are respectively directly below the portion of the insulating film irradiated with infrared rays and the infrared rays. Has a structure for measuring the temperature immediately below the portion where the light is reflected. Therefore, it is possible to obtain a good temperature difference between the first thermosensitive element used for infrared detection and the second thermosensitive element used for temperature compensation, thereby achieving high sensitivity.
Note that an infrared absorption film may be formed on the insulating film and immediately above the first thermosensitive element. In this case, the infrared absorption effect in the first thermal element is further improved, and a better temperature difference between the first thermal element and the second thermal element can be obtained.

A fixing device according to a second invention is characterized in that, in the first invention, the infrared sensor is installed inside the fixing roller.
That is, in this fixing device, an infrared sensor having a thin and low-profile structure is installed inside the fixing roller, so that it is not easily affected by toner or paper dust scattered in the device, and detection deterioration due to these is reduced. can do.

A fixing device according to a third invention is the fixing device according to the first or second invention, wherein the first wiring film is arranged up to the periphery of the first thermal element and has a larger area than the second wiring film. It is formed.
That is, in this fixing device, since the first wiring film is arranged to the periphery of the first thermal element and has a larger area than the second wiring film, the infrared rays of the insulating film are absorbed. While improving the heat collection from the part, the heat capacity is close to the part of the insulating film where the infrared reflective film is formed, so that the fluctuation error can be reduced. In addition, it is preferable that the area and shape of the first wiring film are set to be substantially the same as the infrared reflective film so that the heat capacity is substantially equal to the portion of the insulating film where the infrared reflective film is formed.

According to a fixing device of a fourth invention, in any one of the first to third inventions, the insulating film is formed of a polyimide substrate, and the infrared reflecting film, the first wiring film, and the second wiring. The film is formed of copper foil.
That is, in this fixing device, the insulating film is formed of a polyimide substrate, and the infrared reflecting film, the first wiring film, and the second wiring film are formed of copper foil. A double-sided flexible substrate can be used, and cost reduction can be achieved.

According to a fixing device of a fifth invention, in the fourth invention, the infrared reflecting film is composed of the copper foil and a gold plating film laminated on the copper foil.
That is, in this fixing device, since the infrared reflecting film is composed of a copper foil and a gold plating film laminated on the copper foil, the gold plating film functions as an anti-oxidation film of the copper foil and transmits infrared rays. The reflectance can be improved.

A fixing device according to a sixth aspect of the invention is characterized in that, in any one of the first to fifth aspects, the first thermal element and the second thermal element are thermistor elements.
That is, in this fixing device, since the first and second thermal elements are thermistor elements, the heat resistance is high, and an infrared sensor can be installed closer to the fixing roller, the fixing belt, or the heating mechanism. It becomes possible.

The present invention has the following effects.
That is, according to the fixing device according to the present invention, the infrared sensor installed in the housing includes a first thermal element and a second thermal element provided on one surface of the insulating film so as to be separated from each other, And an infrared reflecting film provided on the other surface of the insulating film so as to face the second heat sensitive element, so that the temperature of the fixing roller or the fixing belt can be accurately detected even if the amount of heat received by the infrared sensor is large. Can be detected in a non-contact manner, and the overall size and cost can be reduced.
Therefore, in an image forming apparatus such as a copying machine, a printer, or a facsimile provided with the fixing device of the present invention, the temperature of the fixing roller and the fixing belt is maintained with high accuracy, and high-quality copying and printing can be performed and the size can be reduced. And cost reduction can be realized.

1 is a schematic configuration diagram illustrating a first embodiment of a fixing device according to the present invention. In 1st Embodiment, it is a perspective view which shows an infrared sensor. In 1st Embodiment, it is a front view which shows an infrared sensor. In 1st Embodiment, it is an enlarged front view of the principal part which shows the part (a) to which the 1st thermosensitive element was adhere | attached, and the part (b) to which the 2nd thermosensitive element was adhere | attached. In 1st Embodiment, it is a bottom view which shows the insulating film before a thermal element is adhere | attached. In 1st Embodiment, it is a top view which shows the insulating film before a thermal element is adhere | attached. FIG. 3 is a schematic configuration diagram illustrating a second embodiment of a fixing device according to the present invention. It is a block diagram which shows the apparatus for performing the performance comparison of the infrared sensor used for this invention. In the infrared sensor used for this invention, it is a graph which shows the change of the absorption film temperature with respect to the temperature change of a Peltier device, and a reflecting film temperature. In the infrared temperature sensor of patent document 2, it is a graph which shows the change of the absorption film temperature and the reflection film temperature with respect to the temperature change of a Peltier device. In the infrared sensor used for this invention, it is a graph which shows the temperature of an infrared sensor, the measured temperature of a desk, and the calculated temperature of a desk. In the infrared temperature sensor of patent document 2, it is a graph which shows the change of the temperature of an infrared temperature sensor, the measured temperature of a desk, and reflective film temperature.

  Hereinafter, a first embodiment of a fixing device according to the present invention will be described with reference to FIGS. In each drawing used for the following description, the scale is appropriately changed in order to make each member recognizable or easily recognizable.

  The fixing device 10 of this embodiment is mounted on an image forming apparatus such as a copying machine, a printer, a facsimile machine, or a printing machine, and forms a fixing nip between the fixing roller 11 and the fixing roller 11 as shown in FIG. A pressure roller 12 for heating, a heating mechanism 13 for generating heat in the fixing roller 11, a housing 14 for holding them inside, and an infrared sensor 1 for detecting the temperature by receiving infrared rays from the fixing roller 11. This is a roller fixing device.

  The heating mechanism 13 controls the halogen heater H based on the temperature of the fixing roller 11 detected by the infrared heater 1 and the halogen heater H that is a heat source disposed inside the fixing roller 11, for example. And a control unit C that keeps the constant. The heating mechanism 13 may be a mechanism that heats the fixing roller 11 by induction heating as a heat source.

The fixing roller 11 is formed by coating a metal core such as aluminum, stainless steel, or iron with a fluororesin or a tube.
The pressure roller 12 is provided with an elastic layer such as silicon rubber on the surface of a cylindrical base made of, for example, a synthetic resin or metal, and a resin excellent in releasability such as a fluororesin on the elastic layer. It is coated with. The pressure roller 12 is rotatably installed in a state where it is in pressure contact with the outer peripheral surface of the fixing roller 11. The fixing roller 11 and the pressure roller 12 are connected to gears, and are driven to rotate in opposite directions by a motor connected to the gears.

As shown in FIGS. 2 to 4, the infrared sensor 1 includes an insulating film 2, a first thermal element 3 </ b> A provided on one surface (lower surface) of the insulating film 2 so as to be spaced apart from each other, and The second heat sensitive element 3B and a pair of first wiring film 4A and second heat sensitive element 3B which are conductive metal films formed on one surface of the insulating film 2 and connected to the first heat sensitive element 3A. A pair of second wiring films 4B, which are conductive metal films connected to each other, and an infrared reflecting film 6 provided on the other surface of the insulating film 2 so as to face the second thermal element 3B. Yes.
The infrared sensor 1 is attached to the inner wall of the housing 14 and is disposed so as to face the other surface of the insulating film 2 toward the outer peripheral surface of the fixing roller 11. The infrared sensor 1 is a resin that is fixed to one surface of the insulating film 2 to support the insulating film 2 and that houses the first and second heat sensitive elements 3A and 3B in an inner housing portion. It may be installed via a sensor housing (not shown).

  As shown in FIG. 5, the first wiring film 4A is arranged up to the periphery of the first thermal element 3A and has a larger area than the second wiring film 4B. These first wiring films 4 </ b> A are provided with a first thermosensitive element 3 </ b> A at the center of a pair, and the outer shape of the first wiring film 4 </ b> A is set to be substantially the same as the infrared reflecting film 6. That is, the area and shape of the first wiring film 4A are substantially the same as those of the infrared reflection film 6, and the heat capacity is set to be substantially equal to the portion of the insulating film 2 where the infrared reflection film 6 is formed.

The pair of first wiring films 4A is connected to the first adhesive electrode 5A formed on the insulating film 2 at one end thereof and to the other end portion on the insulating film 2 respectively. The first terminal electrode 7 </ b> A formed on is connected.
Further, the pair of second wiring films 4B are formed in a linear shape, and one end portion thereof is connected to the second adhesive electrode 5B formed on the insulating film 2, and the other end portion. A second terminal electrode 7B formed on the insulating film 2 is connected to each other.

Note that the terminal electrodes 3a of the first heat sensitive element 3A and the second heat sensitive element 3B are bonded to the first adhesive electrode 5A and the second adhesive electrode 5B, respectively, with a conductive adhesive such as solder.
Further, the first terminal electrode 7A and the second terminal electrode 7B are electrodes for connection with an external circuit.

  The insulating film 2 is formed of a polyimide resin sheet, and the infrared reflection film 6, the first wiring film 4A, and the second wiring film 4B are formed of copper foil. That is, these are both surfaces in which the float electrode of copper foil used as the infrared reflecting film 6, the first wiring film 4A and the second wiring film 4B is patterned on both surfaces of the polyimide substrate used as the insulating film 2. It is made of a flexible substrate.

  Further, as shown in FIG. 6, the infrared reflection film 6 is arranged in a square shape directly above the second heat sensitive element 3B, and is composed of a copper foil and a gold plating film laminated on the copper foil. Has been. A polyimide resin cover is provided on the lower surface of the insulating film 2 to cover the entire lower surface including the first wiring film 4A and the second wiring film 4B except for the first terminal electrode 7A and the second terminal electrode 7B. A ray is formed.

  The infrared reflecting film 6 is formed of a material having an infrared emissivity higher than that of the insulating film 2 and is formed by applying a gold plating film on the copper foil as described above. In addition to the gold plating film, for example, a mirror-deposited aluminum vapor deposition film or an aluminum foil may be used. The infrared reflecting film 6 is formed to cover the second thermal element 3B with a size larger than that of the second thermal element 3B.

  The first heat sensitive element 3A and the second heat sensitive element 3B are chip thermistors in which terminal electrodes 3a are formed at both ends. As this thermistor, there are thermistors of NTC type, PTC type, CTR type and the like. In this embodiment, for example, NTC type thermistors are employed as the first thermal element 3A and the second thermal element 3B. This thermistor is formed of a thermistor material such as a Mn—Co—Cu-based material or a Mn—Co—Fe-based material. The first thermal element 3A and the second thermal element 3B are mounted on the insulating film 2 by bonding the terminal electrodes 3a onto the corresponding first adhesive electrode 5A or the second adhesive electrode 5B. Has been.

  As described above, in the fixing device 10 of the present embodiment, the infrared sensor 1 disposed opposite to the outer peripheral surface of the fixing roller 11 is provided on the one surface of the insulating film 2 so as to be spaced apart from each other. 3A and the second heat sensitive element 3B, and the infrared reflective film 6 provided on the other surface of the insulating film 2 so as to face the second heat sensitive element 3B. The temperature distribution generated in the first detection thermal element 3A and the second compensation thermal element 3B that are arranged side by side is reduced.

  For this reason, both the heat sensitive elements 3A and 3B on the insulating film 2 are simultaneously affected and sensitively affected by the temperature fluctuation due to the heat from the fixing roller 11, so that the radiant heat from the fixing roller 11 is accurately detected. be able to. Therefore, even if the amount of heat received by the infrared sensor 1 is large, the temperature of the fixing roller 11 can be detected in a non-contact manner with high accuracy, and there is no need for a space or a support structure for heat isolation from the fixing roller 11, and the temperature is small. It can be installed in the housing 14 in space, and the overall size and cost can be reduced.

  The infrared sensor 1 includes the infrared reflecting film 6 provided on the other surface of the insulating film 2 so as to face the second thermal element 3B, so that the first thermal element 3A is irradiated with infrared rays. The second thermal element 3B measures the partial temperature of the insulating film 2 that has absorbed infrared rays, while the infrared ray is reflected by the infrared reflecting film 6 so that the infrared absorption is greatly suppressed. Measure partial temperature. Therefore, the second heat sensitive element 3B under the infrared reflecting film 6 which can suppress the influence of infrared rays on the first heat sensitive element 3A and obtain a high reference, and the insulating film 2 which is thin and has low thermal conductivity, A good temperature difference between the first thermal element 3A and the second thermal element 3B can be obtained.

  That is, even in the low thermal conductive insulating film 2 in which the film does not contain an infrared absorbing material or the like, the infrared reflecting film 6 reflects the infrared rays directly above the second heat sensitive element 3B of the insulating film 2 and absorbs the infrared rays. Thus, a temperature difference from the first thermal element 3A directly below the portion that does not reflect infrared rays can be obtained, and the second thermal element 3B can be used as a high reference.

  Further, the medium that conducts heat between the first thermal element 3A and the second thermal element 3B is only the insulating film 2 other than air, and the conducting cross-sectional area is reduced. Accordingly, it is difficult for heat to be transmitted to the mutual heat sensitive elements, interference is reduced, and detection sensitivity is improved. As described above, since the thermal coupling between the first thermal element 3A and the second thermal element 3B is low, they can be arranged close to each other, and the overall size can be reduced. Furthermore, since the infrared rays are shielded by the infrared reflection film 6 rather than the light shielding structure by the frame body or case, it can be manufactured at low cost.

Furthermore, even if the infrared reflective film 6 is made of a conductive material, insulation with the first thermal element 3A and the second thermal element 3B installed with the insulating film 2 interposed therebetween is ensured. An efficient material can be selected regardless of the insulating properties of the film.
In this way, the first heat sensitive element 3A and the second heat sensitive element 3B, on which the influence of heat on the low heat conductive insulating film 2 is suppressed, are respectively irradiated with infrared rays on the insulating film 2. It has the structure which measures the temperature of directly under and the part directly under the part in which infrared rays are reflected. Therefore, it is possible to obtain a good temperature difference between the first thermal element 3A for infrared detection and the second thermal element 3B for temperature compensation, thereby achieving high sensitivity.

Further, since the first wiring film 4A is arranged up to the periphery of the first thermosensitive element 3A and has a larger area than the second wiring film 4B, the portion of the insulating film 2 that absorbs infrared rays As well as improving heat collection from the heat capacity, the heat capacity approaches the portion of the insulating film 2 where the infrared reflective film 6 is formed, so that the variation error can be reduced.
Furthermore, since the infrared reflecting film 6 is composed of a copper foil and a gold plating film laminated on the copper foil, the gold plating film functions as an antioxidant film for the copper foil and improves the infrared reflectance. Can be made.

  Next, a second embodiment of the infrared sensor according to the present invention will be described below with reference to FIG. Note that, in the following description of the embodiment, the same components described in the above embodiment are denoted by the same reference numerals, and the description thereof is omitted.

  The difference between the second embodiment and the first embodiment is that the infrared sensor 1 is attached to the inner wall of the housing 14 in the first embodiment, whereas the fixing device 20 of the second embodiment is different from the first embodiment in FIG. 7, the infrared sensor 1 is installed inside (inside) the fixing roller 11. That is, in the second embodiment, the infrared sensor 1 is installed in a state of facing the inner peripheral surface of the fixing roller 11 with the other surface of the insulating film 2 facing the inner peripheral surface of the fixing roller 11.

  Therefore, in the fixing device 20 of the second embodiment, the infrared sensor 1 having a thin and low-profile structure is installed inside the fixing roller 11, so that the fixing device 20 is hardly affected by toner or paper dust scattered in the device. Detection deterioration due to these can be reduced. In particular, since the first heat sensitive element 3A and the second heat sensitive element 3B are thermistor elements having excellent heat resistance, they can be installed in the vicinity of the halogen heater H.

The infrared sensor 1 used in the fixing device of the present invention was compared with the conventional infrared temperature sensor disclosed in Patent Document 2.
In this experiment, in order to make it easy to compare the sensor performance, as shown in FIG. 8, not the fixing roller of the fixing device, but the desk D with the black body tape T attached is used as the measurement object, and above the desk D. The infrared sensor 1 was installed at intervals, and a Peltier element P was placed on the infrared sensor 1, and the temperature of the desk D was measured while directly heating and cooling the infrared sensor 1. In addition, another temperature sensor (not shown) was directly attached to the desk D, and the temperature (actual value) of the desk D was measured.

First, when the infrared sensor 1 is heated by the Peltier element P, the absorption film temperature (temperature at the first thermal element 3A) and the reflection film temperature (temperature at the second thermal element 3B) in the infrared sensor 1 used in the present invention. FIG. 9 shows the time change between the temperature and the temperature of the Peltier element P. Moreover, each temperature in the said conventional infrared temperature sensor similarly installed and measured as a comparison is shown in FIG.
As can be seen from FIGS. 9 and 10, the conventional infrared sensor described above has a large time change (the difference in inclination between the temperature difference between the absorption film temperature and the reflection film temperature), whereas the infrared sensor used in the present invention. In 1, the time change of the temperature difference between the absorption film temperature and the reflection film temperature is small.

  Next, when the Peltier element P is heated to 48 ° C. from a state where the Peltier element P is not operated (the temperature of the desk D is 22 ° C.), and then cooled to 4 ° C., the temperature of the infrared sensor 1 used in the present invention ( The time change between the “sensor” in the figure), the measured temperature of the desk D (the desk (actually measured) in the figure), and the calculated temperature of the desk D measured by the infrared sensor 1 (the desk (calculated) in the figure). As shown in FIG. Moreover, each temperature in the said conventional infrared temperature sensor similarly installed and measured as a comparison is shown in FIG.

  As can be seen from FIGS. 11 and 12, in the above-described conventional infrared temperature sensor, when the temperature of the infrared temperature sensor greatly changes due to the Peltier element P, the calculated temperature of the desk D measured by the infrared temperature sensor becomes the actually measured temperature of the desk D. On the other hand, in the infrared sensor 1 used in the present invention, the calculated temperature of the desk D measured by the infrared sensor 1 is almost the same as the measured temperature of the desk D. Therefore, the infrared sensor 1 used in the present invention can accurately estimate the temperature of the measurement object as compared with the conventional infrared sensor even if its own temperature changes.

The technical scope of the present invention is not limited to the above embodiments, and various modifications can be made without departing from the spirit of the present invention.
For example, in each of the embodiments described above, a fixing roller is used as a toner image fixing mechanism, but a known fixing belt may be used. In this case, the infrared sensor is disposed to face the fixing belt with the other surface of the insulating film facing.

  In each of the above embodiments, the first heat sensitive element detects the heat conducted from the insulating film that directly absorbs infrared rays. However, the infrared ray is directly on the insulating film and directly above the first heat sensitive element. An absorption film may be formed. In this case, the infrared absorption effect in the first thermal element is further improved, and a better temperature difference between the first thermal element and the second thermal element can be obtained. That is, the infrared ray absorbing film absorbs infrared rays due to radiation from the fixing roller, and the temperature of the first heat-sensitive element immediately below is absorbed by heat conduction through the insulating film from the infrared ray absorbing film that has absorbed infrared rays and generated heat. It may be changed.

This infrared absorbing film is formed of a material having an infrared absorption rate higher than that of the insulating film. For example, a film containing an infrared absorbing material such as carbon black or an infrared absorbing glass film (borosilicate containing 71% silicon dioxide). A material formed of a glass film or the like can be used. In particular, the infrared absorbing film is preferably an antimony-doped tin oxide (ATO) film. This ATO film has better infrared absorption and light resistance than carbon black or the like. In addition, since the ATO film is cured with ultraviolet rays, it has a high adhesive strength and is less likely to be peeled off than carbon black or the like.
In addition, it is preferable to form this infrared rays absorption film so that this may be covered with a larger size than a 1st thermal element.

Moreover, although the 1st thermal element and the 2nd thermal element of a chip | tip thermistor are employ | adopted, you may employ | adopt the 1st thermal element and the 2nd thermal element which were formed with the thin film thermistor.
As described above, the thermosensitive element is preferably a thin film thermistor or a chip thermistor, but a pyroelectric element or the like can also be employed in addition to the thermistor element.

  DESCRIPTION OF SYMBOLS 1 ... Infrared sensor, 2 ... Insulating film, 3A ... 1st thermosensitive element, 3B ... 2nd thermosensitive element, 4A ... 1st wiring film, 4B ... 2nd wiring film, 6 ... Infrared reflective film, 10 , 20 ... fixing device, 11 ... fixing roller, 12 ... pressure roller, 13 ... heating mechanism, 14 ... housing

Claims (5)

A fixing roller or a fixing belt, a pressure roller that forms a fixing nip between the fixing roller or the fixing belt, a heating mechanism that generates heat in the fixing roller or the fixing belt, and these are held inside. A fixing device including a housing,
An infrared sensor that detects the temperature by receiving infrared rays from the fixing roller or the fixing belt;
The infrared sensor is formed on an insulating film, a first thermal element and a second thermal element provided on one surface of the insulating film and spaced from each other, and one surface of the insulating film. A conductive first wiring film connected to the first thermal element, a conductive second wiring film connected to the second thermal element, and the second thermal element facing the second thermal element. An infrared reflective film provided on the other surface of the insulating film,
The infrared sensor is disposed in the casing and inside the fixing roller or the fixing belt so that the other surface of the insulating film faces the inner peripheral surface of the fixing roller or the fixing belt. A fixing device. The fixing device according to claim 1 ,
The fixing device, wherein the first wiring film is disposed up to the periphery of the first thermal element and has a larger area than the second wiring film. The fixing device according to claim 1 or 2 ,
The insulating film is formed of a polyimide substrate;
The fixing device, wherein the infrared reflection film, the first wiring film, and the second wiring film are formed of copper foil. The fixing device according to claim 3 .
The fixing device, wherein the infrared reflecting film is composed of the copper foil and a gold plating film laminated on the copper foil. In the fixing device according to any one of claims 1 to 4 ,
The fixing device, wherein the first thermal element and the second thermal element are thermistor elements.