JP2003254828A - Temperature detecting device and fixing device using it - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a temperature detecting device that can always make accurate temperature detection with a simple constitution by suppressing temperature distribution produced in a sensor unit containing a non-contacting temperature sensor. <P>SOLUTION: This temperature detecting device 3 which detects surface temperature of an object 1 to be heated by means of a heating source 2 is provided with the sensor unit 5 containing the non-contacting temperature sensor 4 which is arranged to face the object 1 and measures infrared rays emitted from the object 1, a mounting substrate 6 on which the sensor unit 5 is mounted, and a heat shielding means 7 which shields the heat transfer from the substrate 6 side to the sensor unit 5. A fixing device uses this temperature detecting device 3. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a temperature detecting device for detecting the surface temperature of an object to be heated, and more particularly to a temperature detecting device using a sensor unit including a non-contact type temperature sensor, a copying machine, a printer, a facsimile, The present invention relates to a fixing device used in an electrophotographic image forming apparatus such as a multifunction peripheral.

[0002]

2. Description of the Related Art Generally, in image forming apparatuses such as copiers, printers, and facsimiles, a fixing device for fixing an unfixed toner image held on a recording sheet by an electrophotographic process is widely used. . Conventionally, this type of fixing device includes, for example, a pair of fixing members (a pair of fixing rolls, a combination of a fixing roll and a fixing belt, etc.) arranged in pressure contact with each other and rolling in contact, and at least one of the fixing members Is heated by a heater as a heating source, and the recording sheet is passed through the nip region between these fixing members, and the unfixed toner image on the recording sheet is fixed by the action of heat and pressure at that time to form a permanent image. Are known to form. In such a fixing device, it is necessary to perform fixing at an appropriate temperature so as to prevent hot offset, cold offset, etc. Therefore, the surface temperature of the fixing member is detected, and the fixing member is detected based on the detection result. The heating is controlled.

One condition for properly controlling the temperature of the fixing member is to accurately detect the surface temperature of the fixing member. More specifically, since how much heat is applied to the toner image on the recording sheet when passing through the nip area becomes a problem, an area where the toner image on the surface of the fixing member contacts (hereinafter referred to as “image area”). To accurately detect the surface temperature of. As a conventional temperature detecting device, in order to accurately detect the surface temperature of the fixing member,
As a contact-type temperature sensor, for example, a method in which a thermistor is brought into contact with the surface of the fixing member and the temperature thereof is detected is often adopted. Further, this method includes a method of bringing the thermistor into contact with the image area of the fixing member and a method of bringing it into contact with a non-image area (corresponding to a sheet non-passing area through which the recording sheet does not pass).

In such a contact type temperature detection system,
The method of contacting the thermistor with the image area of the fixing member is
Although it is ideal from the viewpoint of accurate temperature detection, the contact may damage the image area on the surface of the fixing member, resulting in poor fixing at the damaged portion, resulting in image defects. Further, if the offset toner adheres to and accumulates on the thermistor, the temperature detection accuracy deteriorates. Further, when the deposited offset toner image comes off the thermistor, the offset toner lumps are fixed on the recording sheet, resulting in an image defect.

On the other hand, the method of bringing the thermistor into contact with the non-image area of the fixing member does not cause problems such as image defects due to these contact scratches, deterioration of detection accuracy due to toner adhesion and image defects, but from the viewpoint of accurate temperature detection. Is not always the preferred method. That is, although ideally the temperature of the image area on the fixing member should be detected,
Since the surface temperature of the non-image area is actually measured, a discrepancy occurs between these temperatures.

Therefore, instead of the contact type temperature detection method,
A method has already been proposed that uses a non-contact temperature sensor to detect temperature without contacting the fixing member (non-contact temperature detection method), and in order to improve temperature detection accuracy,
It has been proposed to incorporate a thermistor for temperature correction (see Japanese Patent Laid-Open No. 5-100591).

[0007]

However, in the embodiment using the non-contact type temperature detection system, for example, the bottom portion of the infrared sensor (non-contact type temperature sensor) is attached in close contact with the attachment substrate. (For example, a temperature detection device used in a microwave oven) Here, when the infrared sensor is used in a microwave oven, the distance between the DUT and the infrared sensor is, for example, about 200 mm, Further, since the temperature of the object to be measured is, for example, 100 ° C. or lower, the temperature of the infrared sensor is about room temperature, there is no temperature distribution, and it is not necessary to consider temperature correction. However, for example, when the infrared sensor is used for the fixing device, due to the layout limitation of the fixing device,
The distance between the fixing device, which is the object to be measured, and the infrared sensor needs to be set to, for example, 100 mm or less. However, if the distance is set to 100 mm or less, the temperature of the infrared sensor is affected by the radiant heat of the fixing device. There is a concern that the temperature will rise above 50 ° C. At this time, if the bottom surface portion of the infrared sensor body is attached in close contact with the mounting substrate, heat is conducted from the mounting substrate to the bottom surface portion of the infrared sensor body, and a temperature distribution is generated in the infrared sensor body. As a result, a temperature difference occurs between the thermopile part for detecting the temperature and the temperature compensating thermistor, which causes a technical problem that the temperature compensation cannot be performed accurately.

The present invention has been made in order to solve the above technical problems, and suppresses the temperature distribution generated in a sensor unit including a non-contact temperature sensor, and has a simple structure and always provides accurate temperature detection. The present invention provides a temperature detecting device capable of performing the above and a fixing device using the same.

[0009]

That is, according to the present invention, as shown in FIG. 1, an object to be heated 1 heated by a heating source 2 is heated.
In the temperature detection device 3 for non-contact detection of the surface temperature of
A sensor unit 5 including a non-contact type temperature sensor 4 arranged to face the object to be heated 1 and measuring infrared rays emitted from the object to be heated 1, a mounting substrate 6 on which the sensor unit 5 is mounted, and mounting From the substrate 6 side to the sensor unit 5
And a heat cutoff means 7 for cutting off heat transfer to.

In such a technical means, the object to be heated 1 which is the object of temperature detection can be any object as long as it is heated, and the main one is a fixing device. Here, the fixing device may be a roll-shaped one or an endless belt-shaped one stretched by a plurality of rolls.
The object to be heated 1 may be heated by the heating source 2, and the location of the heating source 2 may be inside or outside the object to be heated 1 and may be in contact with the object to be heated 1. It may be arranged, or may be arranged in a non-contact manner.

As the temperature sensor 4, the object to be heated 1
Various types of surface temperature can be selected as long as the surface temperature can be detected in a non-contact manner, but an inexpensive thermopile type temperature sensor having characteristics of high sensitivity and high speed response can be used. preferable.

The sensor unit 5 includes a temperature sensor 4
And is designed to be mounted on the mounting substrate 6,
Usually, it is composed of a base member on which the temperature sensor 4 is installed, and a can-shaped housing in which an infrared transmissive optical filter is fitted. Further, from the viewpoint of more accurate temperature measurement, the sensor unit 5 preferably includes a correction sensor in addition to the temperature sensor 4. Here, the correction sensor may be selected as appropriate as long as it is provided to correct the temperature information of the temperature sensor 4, but from the viewpoint of simplification of the configuration, the detection method may be appropriately selected. It is preferable to use a sensor whose electric resistance value changes. Specific examples of this include a thermistor and a diode. Further, the number of correction sensors may be one or plural, and even when a plurality of correction sensors are used, those having the same characteristics (resistance value or the like) or those having different characteristics may be used. .

In such technical means, it is preferable that the temperature detecting device 3 is provided with a heat blocking means 7 for blocking heat transfer from the mounting substrate 6 side to the sensor unit 5. Normally, since the bottom surface of the sensor unit 5 is mounted in close contact with the mounting board 6, it is greatly affected by heat conduction from the mounting board 6, but by providing the heat blocking means 7,
Such inconvenience can be improved. As a specific mode of the heat blocking means 7, it is preferable to mount the sensor unit 5 on the mounting substrate 6 with a gap provided between the bottom surface of the sensor unit 5 and the mounting substrate 6. Here, the sensor unit 5 has an output extraction terminal on the bottom surface thereof, and is mounted on the mounting substrate 6 via the output extraction terminal, and the gap is provided using the output extraction terminal. It is designed to be used. More specifically, the sensor unit 5
As means for mounting the mounting board 6 on the mounting board 6, for example, an output terminal provided on the base member is inserted into the mounting board 6 to keep the sensor unit 5 and the mounting board 6 separated from each other. There is a mode in which the lower surface side of the is joined by soldering or the like.

Further, as another mode of the heat shield means 7, it is preferable that a heat insulating material is provided between the sensor unit 5 and the mounting board 6, and the sensor unit 5 is mounted on the mounting board 6 via this heat insulating material. . Further, it is preferable that the heat insulating material is configured to include glass fiber or aramid fiber. Here, as the heat insulating material, it is sufficient that the heat insulating material has a heat conductivity such that the influence of heat conduction to the sensor unit 5 side can be ignored, and specifically, 0.837 W / m · K (2.0 × 10
^-3 cal / cm · sec · ° C.) or less is preferable. Further, from the viewpoint of safety, it is preferable that the heat insulating material is made of a nonflammable material. Further, the material is not limited to glass fiber or aramid fiber, and any material having a low thermal conductivity may be appropriately selected, and preferably foam (polyimide, silicone rubber, sponge sheet, etc.)
It is preferable to use a heat-resistant resin (epoxy resin or the like) or an elastomer such as rubber.

The temperature detecting device 3 as described above is applied to detect the temperature of various objects to be heated 1. An application example to a fixing device will be described as a typical example. Although there are various modes of the fixing device, as an example of application to the fixing device, for example, a pair of fixing members which are arranged in pressure contact with each other and roll in contact with each other (heated member 1).
And a heating source 2 is provided inside or outside at least one of the fixing members, and the surface temperature of at least one of the fixing members is detected by a temperature detecting device 3. Is mentioned. In this aspect, "the surface temperature of one of the fixing members is detected" means that the fixing member provided with the heating source 2 is the heated object 1 which is directly heated, and the heating source 2 A fixing member not provided with is heated indirectly by heat conduction.
Therefore, both are targets for temperature detection. The heating source 2 includes any mode in which the heating source 2 is in non-contact with or in contact with the object to be heated 1.

As another application example to the fixing device,
An image-bearing carrier (corresponding to the heated body 1) having a heating layer and carrying an unfixed image, and a heating device (corresponding to the heating source 2) for heating the heating layer of the image-bearing carrier. A press-fixing member that is disposed at a position downstream of a portion of the image-carrying and transporting member facing the heating device and that transfers and fixes the unfixed image melted on the image-carrying and transporting member onto the recording member by pressing at least (depending on the case). (Corresponding to the heated body 1), and the surface temperature of the image carrier or the pressure fixing member is detected by the temperature detecting device 3. In this aspect, the heat generating layer includes an electromagnetic induction heat generating layer and a resistance heat generating layer. The heating device may be appropriately selected according to the heating layer, and examples thereof include an exciting coil for the electromagnetic induction heating layer and an energization device for the resistance heating layer. Further, the pressing and fixing member has only to have at least a pressing function, and it is possible to appropriately select a member such as an auxiliary electrostatic field to act as necessary.

[0017]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will be described below in detail based on the embodiments shown in the accompanying drawings. First Embodiment FIG. 2 is an explanatory diagram showing the overall configuration of the first embodiment of the fixing device to which the present invention is applied. In the figure, the fixing device includes a pair of fixing rolls 11 and 12 which are arranged in pressure contact with each other and roll in contact with each other.
Although lamp heaters 13 and 14 are built in 1 and 12, respectively, and the fixing rolls 11 and 12 may be appropriately selected, for example, a coating layer made of a heat-resistant urethane resin is provided on a metal roll shaft. Fusing roll 1
A predetermined fixing nip area is secured between 1 and 12.

Further, in the present embodiment, a pair of temperature detecting devices 15 (specifically, 15a and 15b) for detecting the surface temperatures of the fixing rolls 11 and 12 in a non-contact manner are provided. In the present example, the temperature detection device 15 is arranged at a position corresponding to a sheet passage area through which the recording sheet P passes, of the axial positions of the fixing rolls 11 and 12, for example.

Further, in the present embodiment, the detection data from the temperature detection device 15 (15a, 15b) is taken in by the temperature control device (calculating means) 16, and this temperature control device 16 of each of the fixing rolls 11, 12. The surface temperature is calculated, and a control signal is sent to the power supply circuit 17 based on the calculation result to control ON / OFF of the lamp heaters 13 and 14.

FIG. 3 is a perspective sectional view of a sensor unit in the temperature detecting device 15 (15a).
In the present embodiment, the sensor unit 20 includes a thermopile chip (non-contact type temperature sensor) 21 that receives infrared rays emitted from the fixing rolls 11 and 12, and a thermopile chip 21 having a convex cross section. The base member 22 to be placed, the thermistor (correction sensor) 23 mounted on the base member 22 in the vicinity of the thermopile chip 21, and the thermopile chip 21 and the thermistor 23 by being attached so as to cover the base member 22.
And a can-shaped housing 24 that shields the air from the outside air. In addition, a silicon lens 25 is provided on the upper wall surface of the can-shaped housing 24.
Is installed. Here, an inert gas such as nitrogen gas or Ar gas is sealed inside the can-shaped housing 24.
Reference numerals 26 and 27 denote thermopile output terminals to which the thermoelectromotive force generated in the thermopile chip 21 is output via the lead wire (thermoelectromotive force is a group of a large number of thermocouples that connect hot contacts and cold contacts in series). The thermistor output occurs at both ends, and in this example, reference numeral 26 is one end side terminal of the thermocouple group, reference numeral 27 is the other end terminal of the thermocouple group), and reference numeral 28 is the thermistor output from which the voltage of the thermistor 23 is output via the lead wire. A terminal, reference numeral 29, is a GND terminal to which the potential of the base member 22 is output via the lead wire. Each of these terminals is connected to the temperature control device 16 (see FIG. 2).

Here, the thermopile chip 21 is a temperature measuring element having a thermopile 21a in which a large number of thermocouples, for example, which bond silicon and aluminum, are connected in series, and the hot junction has an insulating thin film (not shown) having a small heat capacity. No.), the cold junction is placed on the heat sink 21b made of silicon, and the hot junction is covered with an infrared absorber (not shown).

FIG. 4 shows the mounting structure of the sensor unit 20 on the mounting substrate 30. In the present embodiment, the mounting structure of the sensor unit 20 is the base member 2
2, output takeout terminals 26, 27, 28, 29
Each of them is inserted into the mounting substrate 30 and joined from the lower surface side of the mounting substrate 30 with solder or the like. At this time, a gap having a separation distance h is provided between the base member 22 and the mounting substrate 30, and the sensor unit 20 is supported by the output extracting terminals 26, 27, 28, 29, respectively. It is mounted on the mounting substrate 30 via this gap.

Next, the operation of the temperature detecting device of the fixing device according to the present embodiment will be described. As shown in FIGS. 2 and 3, when the heating of the fixing roll 11 (12) is started, the temperature detecting device 15 displays the fixing roll 11 (1).
The infrared light emitted from 2) is irradiated. At this time, the infrared rays reaching the portion facing the silicon lens 25 are
It is condensed by the silicon lens 25 and is irradiated onto the thermopile 21 a of the thermopile chip 21. Then, the hot junction of the thermopile 21a is heated, a thermoelectromotive force due to the Seebeck effect is generated between the thermopile 21a and the cold junction, and the temperature control device 16 is supplied via the thermopile output terminals 26 and 27.
Entered in. On the other hand, in the thermistor 23, the electric resistance value changes according to the temperature of the base member 22, and the output voltage thereof is also input to the temperature control device 16 via the thermistor output terminal 28.

In the present embodiment, the sensor unit 20 is mounted by providing a gap between the base member 22 and the mounting substrate 30 as a heat blocking means for blocking heat transfer from the mounting substrate 30 side to the sensor unit 20. Since it is mounted on the substrate 30, the air present in the gap exerts a heat insulating effect, and the mounting substrate 3
It is possible to prevent heat transfer from 0 to the base member 22. Therefore, the occurrence of temperature distribution in the sensor unit 20 can be suppressed, and accurate temperature detection can be performed. Further, although the sensor unit 20 and the mounting substrate 30 are mounted via the output extracting terminals 26, 27, 28, 29, the output extracting terminals 26, 27, 28, 2 are provided.
Since the size of 9 itself is small and the cross-sectional area thereof is also extremely small, heat conduction from the terminals 26, 27, 28, 29 to the base member 22 has almost no effect. Such heat insulation performance is supported by the examples described later.

Further, as another aspect of the fixing device to which the present invention is applied, the fixing belt and the pressure roll are arranged in pressure contact with each other, and the inside of the fixing belt corresponding to the fixing nip region between the fixing belt and the pressure roll is provided. A holder is disposed on the holder, and an elastic pad is disposed on the holder via a heater.In addition, a pair of fixing rolls that are arranged in pressure contact and roll in contact with each other are provided. An external heating roll may be disposed in contact with the fixing roll to heat the outer surface of the fixing roll.

Second Embodiment FIG. 5 shows a second embodiment of the sensor unit mounting structure to which the present invention is applied. In the figure, the mounting structure of the sensor unit 20 is substantially the same as that of the first embodiment, but unlike the first embodiment, the heat insulating material 40 is provided between the base member 22 and the mounting substrate 30, and the heat insulating material 40 is provided. The sensor unit 20 is mounted on the mounting substrate 30 via the. That is, in this embodiment, the heat insulating material 40 is adhered to the mounting board 30, and the output extracting terminals 26, 27, 28, 29 provided on the base member 22 are inserted into the mounting board 30 through the heat insulating material 40. The lower surface of the mounting substrate 30 is joined by soldering or the like. Here, the heat conductivity of the heat insulating material 40 is preferably in a range in which the influence of heat conduction from the mounting substrate 30 to the sensor unit 20 side can be ignored, and specifically, 0.837 W / m · K (2 ．
The range is preferably 0 × 10 ⁻³ cal / cm · sec · ° C.) or less. Further, the heat insulating material 40 is preferably composed of a non-combustible material from the viewpoint of ensuring safety, and typical examples thereof include glass fiber or aramid fiber. , Silicone rubber, sponge sheet, etc., heat-resistant resin (epoxy resin, etc.), elastomer such as rubber, etc. are also preferable. still,
Constituent elements similar to those in the first embodiment are designated by the same reference numerals as those in the first embodiment, and detailed description thereof will be omitted here.

In this embodiment, a heat insulating member 40 is provided between the base member 22 and the mounting substrate 30 as a heat blocking means for blocking heat conduction from the mounting substrate 30 side to the sensor unit 20.
Since the sensor unit 20 is provided and the sensor unit 20 is mounted on the mounting substrate 30 via the heat insulating material 40, it is possible to obtain the same effect as in the first embodiment of preventing heat conduction from the mounting substrate 30 to the base member 22. Further, since it is sufficient to locally provide the heat insulating material 40 only to a portion where the base member 22 is in contact with the mounting board 30, the entire mounting board 30 is covered with the heat insulating material 4.
Since it is not necessary to provide 0, the degree of freedom in design is improved. Furthermore, since the base member 22 is attached in contact with the heat insulating material 40 and is placed on the heat insulating material 40, the sensor unit 20 has the output extraction terminals 26, 27, 28 as in the first embodiment. , 29, the wobble is suppressed and the mounting accuracy is improved.

Third Embodiment FIG. 6 shows an image forming apparatus incorporating the third embodiment of the fixing device to which the present invention is applied. In the figure, this image forming apparatus is provided with an intermediate transfer belt 70 which is wound around two stretching rolls 71 and 72 and whose peripheral surface moves around, and at a position facing the intermediate transfer belt 70. Four image forming units 80 (80Y, 80) on which yellow, magenta, cyan, and black toner images are formed, respectively.
M, 80C, 80K). here,
Each of the image forming units 80 (80Y to 80K) includes, for example, a photosensitive drum 81 on which an electrostatic latent image is formed, a charging device 82 that charges the surface of the photosensitive drum 81 substantially uniformly, and the photosensitive drum 81. An exposure device 83 that irradiates a laser beam onto the latent image to form a latent image, and a developing device 84 that selectively transfers toner to the latent image on the photosensitive drum 81 to form a toner image are provided. Reference numeral 85 is arranged so as to face the photoconductor drum 81 with the intermediate transfer belt 70 interposed therebetween, and a predetermined transfer nip area is formed between the photoconductor drum 81 and the intermediate transfer belt 70 to form the photoconductor drum 81. It is a primary transfer device (primary transfer roll in this example) that primarily transfers the toner images of the respective colors to the intermediate transfer belt 70 side.

Further, in the present embodiment, the fixing device includes an intermediate transfer belt 70 capable of generating heat, and the intermediate transfer belt 70 in the heating area Z in front of the transfer fixing area X (in this example, the stretching roll 72 portion). A heating device 90 that heats the intermediate transfer belt 70 and a pressing and fixing roll 100 that is arranged to face the tension roll 72 in the transfer and fixing area X of the intermediate transfer belt 70 and presses the intermediate transfer belt 70 are provided. Here, as shown in FIG. 7, the intermediate transfer belt 70 includes a base layer 70a made of a resin having high heat resistance such as polyimide, polyamide, and polyimideamide, and an electromagnetic induction heating layer (conductive layer) laminated thereon. Basically, there are provided three layers of 70b and a surface release layer 70c which is the uppermost layer and has a high release property such as fluororesin and silicone resin. The electromagnetic induction heating layer 70b may be appropriately selected as long as it self-heats due to the electromagnetic induction heating action, and examples thereof include copper, silver, and aluminum. Specific resistance, thermal efficiency, and manufacturability (etching). Considering the ease of processing) and the cost,
Copper is the best choice.

The heating device 90 is arranged inside the intermediate transfer belt 70 as shown in FIGS. 6 and 7, and is arranged along the width direction orthogonal to the conveyance direction of the intermediate transfer belt 70. Non-magnetic long plate-like pedestal 91 provided
A magnetic core 92 made of ferrite or the like arranged in the center of a recess formed in the pedestal 91, and a magnetic field generated around the magnetic core 92 in the thickness direction of the intermediate transfer belt 70. The excitation coil 93 is provided, and the exciting circuit 94 supplies power to the excitation coil 93 to generate a fluctuating magnetic field H, and the electromagnetic induction heating layer 70 of the intermediate transfer belt 70.
An eddy current Ic is generated in b to heat the electromagnetic induction heating layer 70b.

Further, in such a fixing device, in the present embodiment, the temperature detection for detecting the temperature of the heating region Z of the intermediate transfer belt 70 is provided outside the intermediate transfer belt 70 corresponding to the heating device 90. A device 130 is provided. In the present embodiment, temperature detecting device 130 has the same configuration as temperature detecting device 15 described in the first and second embodiments. The temperature detection device 130 is connected to the temperature control device as shown in the first embodiment to input temperature data for temperature control.

Next, the operation of the fixing device and the temperature detecting device according to the present embodiment will be described. As shown in FIG. 6, toner images of different colors are formed on the photosensitive drum 81 by the image forming units 80 (80Y to 80K). On the other hand, the intermediate transfer belt 70 circulates in a fixed direction, and at the primary transfer portion of each image forming unit 80, the toner image on the photosensitive drum 81 is transferred onto the intermediate transfer belt 70 by the primary transfer device 85. . Then, after the toner images are sequentially transferred from the four image forming units 80, the superimposed four color toner images T are conveyed to the heating area Z facing the heating device 90 by the movement of the intermediate transfer belt 70.

In this heating area Z, the intermediate transfer belt 70
The upper four-color toner image is melted by the heat generation of the electromagnetic induction heating layer 70b by the electromagnetic induction heating. After that, the melted toner image T is transferred onto the transfer / fixing area X and the pressing / fixing roll 100
Is pressed against the recording sheet P at room temperature by the pressing action of the toner image T, the toner image T penetrates into the recording sheet P and is transferred and fixed, and the toner image T is cooled while being conveyed toward the exit side of the fixing nip area. It At the exit of the fixing nip area, the temperature of the toner is sufficiently low and the cohesive force of the toner is large. Therefore, the toner image is directly transferred and fixed on the recording sheet P as it is without causing offset.

In such a fixing process, the temperature detecting device 130 detects the surface temperature of the intermediate transfer belt 70 in the heating region Z, and the temperature controlling device (not shown) excites the heating device 90 based on the detected temperature. It is adapted to control the circuit 94. Particularly, in the present embodiment, when the intermediate transfer belt 70 is heated by the heating device 90, infrared rays emitted from the intermediate transfer belt 70 are applied to the detection surface of the thermopile provided in the temperature detection device 130.

Also in this embodiment, by using the temperature detecting device 15 described in the first and second embodiments as the temperature detecting device 130, accurate temperature detection can be performed.

[0036]

EXAMPLE FIG. 8A shows a relationship between time and temperature of a fixing roll and a non-contact type temperature sensor in an example using the temperature detecting device according to the first embodiment.
FIG. 8B is a comparative example using a conventional temperature detection device (a mode in which the bottom surface of the sensor unit is arranged in contact with the mounting substrate).
3 shows the relationship between time and temperature of the fixing roll and the non-contact temperature sensor. Incidentally, FIG. 8 (a)
In (b), the curve A shows the actual temperature of the fixing roll, and the curve B shows the temperature detected by the non-contact temperature sensor. In the figure, when the heating of the fixing roll is started and the warm-up operation is completed, the actual temperature of the fixing roll (curve A) and the temperature detected by the non-contact temperature sensor (curve B) show constant values.

However, in the case of the comparative example (the mode in which the sensor unit is arranged in contact with the mounting substrate), the configuration shown in FIG.
As shown in (b), a large difference occurs between the actual temperature of the fixing roll (curve A) and the detected temperature of the non-contact temperature sensor (curve B), which causes a measurement error. In contrast,
In the case of the embodiment, as shown in FIG. 8A, due to the heat insulating effect of the air present at the distance h (see FIG. 4) between the sensor unit and the mounting substrate, the actual temperature of the fixing roll (curve A ) And the temperature detected by the non-contact temperature sensor (curve B) are improved. More specifically, FIG. 9 shows the result of measuring the temperature difference between the actual temperature of the fixing roll and the temperature detected by the non-contact temperature sensor with respect to the separation distance h in the example. According to the figure, by providing a gap between the sensor unit and the mounting substrate, the temperature difference between the actual temperature of the fixing roll and the temperature detected by the non-contact temperature sensor is significantly reduced. To be understood. Further, the effect in the embodiment is significant in that a gap is provided between the sensor unit and the mounting substrate, and it can be said that it is sufficient if the separation distance h can be secured at a certain value (1 mm in this example) or more.

[0038]

As described above, according to the present invention, a sensor unit including a non-contact temperature sensor,
Since the mounting board on which the sensor unit is mounted and the heat blocking means for blocking the heat transfer from the mounting board side to the sensor unit are provided, the temperature distribution generated in the sensor unit due to the heat transfer from the mounting board is suppressed. Therefore, it is possible to always perform accurate temperature detection with a simple configuration.

[Brief description of drawings]

FIG. 1 is an explanatory diagram showing an outline of a temperature detection device according to the present invention.

FIG. 2 is an explanatory diagram showing an overall configuration of a fixing device according to Embodiment 1 to which the present invention is applied.

FIG. 3 is a perspective sectional view of a sensor unit in the temperature detection device according to the first embodiment.

FIG. 4 is an explanatory diagram showing a mounting structure of the sensor unit according to Embodiment 1 to a mounting substrate.

FIG. 5 is an explanatory diagram showing a mounting structure of a sensor unit according to a second embodiment to a mounting substrate.

FIG. 6 is an explanatory diagram showing an image forming apparatus incorporating a fixing device according to a third embodiment to which the invention is applied.

FIG. 7 is an explanatory diagram showing details of a heating device used in the third embodiment.

FIG. 8A is a graph showing a relationship between time and temperature of a fixing roll and a non-contact type temperature sensor in an example using the temperature detecting device according to the first embodiment, and FIG. FIG. 6 is a graph showing a relationship between time and temperature of a fixing roll and a non-contact type temperature sensor in a comparative example using a temperature detecting device.

FIG. 9 is an explanatory diagram showing the measurement results of the temperature difference between the actual fixing roll temperature and the temperature detected by the non-contact temperature sensor with respect to the separation distance h in the example.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Object to be heated, 2 ... Heating source, 3 ... Temperature detection device, 4 ... Non-contact type temperature sensor, 5 ... Sensor unit, 6 ... Mounting board, 7 ... Heat blocking means

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ Identification code FI theme code (reference) G03G 15/24 G03G 15/24 3K059 H05B 3/00 310 H05B 3/00 310E 335 335 6/14 6/14 (72) Inventor Masahiro Ishino 3-7-1 Fuchu, Iwatsuki City, Saitama Prefecture Fuji Xerox Co., Ltd. (72) Inventor Shinichiro Taga 2274 Hongo, Ebina City, Kanagawa Prefecture Fuji Xerox Co., Ltd. (72) Inventor Kijima Katsu 430 Nakai-cho, Ashigarashami-gun, Kanagawa Prefecture Green tech Naka Fuji Xerox Co., Ltd. (72) Inventor Atsumi Kurita 2274 Hongo, Ebina City, Kanagawa Fuji Xerox Co., Ltd. F term (reference) 2G066 AC16 BA08 BA60 BB11 CA15 CA20 2H033 BA25 BA31 BA32 BB01 BB14 BB28 BB33 BB39 BE06 BE09 CA07 CA30 2H078 AA21 BB01 CC06 DD03 DD51 DD56 2H200 GA12 GA23 GA47 GB22 GB40 HA02 HB12 JA02 JA07 JC03 JC09 JC13 JC15 JC16 JC17 MA04 MA12 MA20 MB01 MC08 3K058 AA42 BA18 CA12 CA22 CA70 DA02 GA06 3K059 AB19 AC33 AD04 CD72

Claims (8)

[Claims] 1. A temperature detection device for non-contact detection of a surface temperature of an object to be heated which is heated by a heating source, the non-contact type device being arranged to face the object to be heated and measuring infrared rays emitted from the object to be heated. A temperature detecting device comprising: a sensor unit including a temperature sensor; a mounting substrate on which the sensor unit is mounted; and a heat blocking unit that blocks heat transfer from the mounting substrate side to the sensor unit. 2. The temperature detecting device according to claim 1, wherein the sensor unit includes a non-contact type temperature sensor and a correction sensor. 3. The temperature detecting device according to claim 1, wherein the heat cutoff unit has a gap between the bottom surface of the sensor unit and the mounting substrate on which the sensor unit is mounted. Temperature detection device. 4. The temperature detecting device according to claim 3, wherein the sensor unit has an output extracting terminal at the bottom thereof,
A temperature detecting device, characterized in that the temperature detecting device is mounted on a mounting substrate via the output extracting terminal. 5. The temperature detecting device according to claim 1, wherein the heat cutoff unit is provided with a heat insulating material between the bottom surface of the sensor unit and the mounting substrate on which the sensor unit is mounted. Temperature detection device. 6. The temperature detecting device according to claim 5, wherein the heat insulating material is configured to include glass fiber or aramid fiber. 7. A pair of fixing members which are arranged in pressure contact with each other and roll in contact with each other, a heating source is provided inside or outside of at least one fixing member, and a surface temperature of at least one of the fixing members. A temperature detecting device for detecting a temperature of the toner without contacting the fixing member, wherein the temperature detecting device according to any one of claims 1 to 6 is used. 8. An image carrier carrying body having a heat generating layer and carrying and carrying an unfixed image, a heating device for heating the heat generating layer of the image carrying carrier, and a heating device for the image carrying carrier. And an image-bearing carrier or a pressure-fixing member, which is provided at a position downstream of the portion for fixing and fuses the unfixed image melted on the image-bearing carrier onto the recording material by transferring and fixing it. The temperature detecting device according to any one of claims 1 to 6, wherein the temperature detecting device detects the surface temperature of the sheet by a temperature detecting device that measures the surface temperature of the sheet without contacting the image carrier or the pressure fixing member. A fixing device characterized by the above.