JPH0348127A - Noncontact temperature measuring method and temperature sensor - Google Patents

Abstract

PURPOSE:To measure the surface temp. of an object to be measured with high accuracy by providing a sensor head flat plate equipped with a temp. sensor in close vicinity to the surface of the object to be measured and measuring the temp. of the flat plate due to the heat conduction of an interposed air layer. CONSTITUTION:A square opening 21a is formed to an SUS plate 21 folded into an L-shape. A thermistor 6 and an electrode 5 are provided to the SiO2 film of an Si substrate 4 and a copper foil lead 8 is provided on a polyimide film 7 to mount a substrate 4. The polyimide tape 22 of this constitution is bonded to the front and rear surfaces of the SUS plate 21 so as to make a round and the substrat 4 is fitted in the opening 21a to be mounted to the SUS plate 21. The sensor constituted as mentioned above is arranged in the vicinity of the surface of an object 1 to be measured and the surface temp. of the object to be measured is estimated through an air layer. By this constitution, measuring temp. and surface temp. can be measured with good linearity and only the heat resistance of the air layer becomes a disturbance factor to receive no effect of a surface state.

Description

Detailed Description of the Invention [Industrial Application Field] The present invention relates to a non-contact thermometer (n) method and its temperature sensor, and more specifically, the present invention relates to a non-contact thermometer (n) method and its temperature sensor. The present invention relates to a non-contact thermometer n1 method, its temperature sensor, and a temperature detection device to which this temperature sensor is applied, particularly to a temperature detection device used in a fixing device such as an electrophotographic copying machine.

[Prior Art] A non-contact temperature measurement method is a method for measuring the temperature of an object to be measured without contact, and an optical pyrometer has been a typical method for this purpose for a long time. However, in recent years, the development of temperature sensor technology has made significant progress, and the value of its use has increased with the advent of radiation thermometers and the like.

In other words, non-contact temperature measurement has features such as being able to measure the temperature of moving objects and minute objects without affecting the measurement target, and being able to measure rapid temperature changes with excellent responsiveness. It is attracting attention and being adopted. Hereinafter, the main non-contact temperature measuring means, either conventional or in the development stage, will be explained.

l) A radiation thermometer is a mainstream means of non-contact temperature measurement, and is a measuring instrument that measures the brightness temperature of an object that emits thermal radiation. In other words, it is a radiometer that is scaled by a black body with a known temperature, and usually uses a photoelectric conversion element and a detector, and is contrasted with an ancient optical pyrometer. It measures temperature using a wavelength range from visible to about 10-degrees, and is at the stage where it is possible to measure temperatures below room temperature.

2) There is a temperature measuring means currently in the experimental stage called an eddy current sensor. The conductor plate to be measured is placed under the coil, and since the conductor plate cuts off the alternating magnetic flux that is generated when alternating current is passed through the coil, eddy currents flow within it. The magnetic flux generated by this eddy current is generated in a direction that cancels out the magnetic flux of the upper coil, so the eddy current acts in the direction of reducing the magnetic flux of the coil. This decrease means that even if the coil current remains the same, the magnetic flux decreases, so the inductance value of the coil decreases.If you measure the amount of decrease in the value of the coil inductance L, you can determine the increase in eddy current from the change in eddy current loss. I understand. In this method, by utilizing the fact that the magnitude of eddy current depends on temperature, it is possible to determine n1 of the conductor plate temperature from changes in eddy current loss.

3) With a non-contact thermometer n1 means called heat flow compensation method,
A heat flow compensator is installed close to the surface to be measured, and the temperature at two points in the heat flow direction is determined by a contact thermometer such as a thermocouple. This method controls heating and uses the temperature at that time as the surface temperature of the surface to be measured.

In addition, the conventional temperature detection devices mentioned above, especially those in fixing devices, have been mainly of the type in which the temperature detection part is brought into contact with the surface of a rotating body (hereinafter referred to as the fixing roller), but recently, There is a problem that oil-less and small amount oil application fixing is becoming more common, which reduces the lubrication effect of the fixing roller, and increases the wear of the fixing roller due to this contact.As a way to solve this problem, the upstream side of the temperature detection part However, these devices generally complicate the overall structure and are expensive.

[Problems to be Solved by the Invention] While the conventional non-contact temperature measurement methods as described above have their own advantages, they also have the following practical problems.

■) Issues with radiation thermometers: (a) Radiation thermometers are expensive (many of them cost hundreds of thousands of yen or more), so they are used in industrial processes, but it is difficult to use them in consumer equipment.

(b) Since radiation is used, an optical system is required, making the device large and complicated.

(c) In the low temperature range (0 to 200°C), infrared heat detection sensors (thermopile, thermistor bolometer) are used.

Since a pyroelectric element (pyroelectric element) is used, temperature fluctuations in the sensor itself can cause errors, so temperature compensation for the sensor is required.
The circuit device becomes complicated.

(d) Since it is affected by emissivity, emissivity correction is necessary for accurate ITIIJ determination.

(e) The circuit is complicated because the radiance is a nonlinear function of absolute temperature to the 0th power.

2) Issues with the eddy current method: This has only been done experimentally. Also, (a) only metals can be measured.

(b) Affected by metal components.

(c) There is an effect of distance.

3) Issues with heat flow compensation method: Since heating control of the heater is required, thermal response is poor and it is not practical.

Furthermore, a non-contact type temperature sensor is used as a temperature detection device in the above-described fixing device. However, since this type of conventional temperature sensor is a non-contact type, its thermal response is slow, resulting in a decrease in temperature detection accuracy, and, for example, overshoot frequently occurs when the fixing device starts up. Furthermore, positioning is required to ensure an appropriate gap between the temperature detecting portion of the temperature sensor and the fixing roller, but there is a problem in that this work is troublesome and takes a long time to assemble.

This invention was made in order to solve the problems of the temperature CI standard method as described above, and it enables the surface temperature of objects (including moving objects) between room temperature and 200°C to be measured in a non-contact state, and is small and compact. Measured by cheap temperature sensor and detector? #1
In addition to providing a method and a temperature sensor thereof, the present invention solves the problems of the conventional temperature sensing device as described above, and has good responsiveness, high temperature sensing accuracy, and easy positioning of the temperature sensing portion with respect to the fixing roller. The object of the present invention is to provide a temperature sensor that can be assembled in a short time.

[Means for Solving the Problems] In the non-contact thermometer 7#1 method according to the present invention, a flat plate of a sensor head made of a good thermal conductor and equipped with a temperature sensor is installed near the surface of an object to be measured, and the flat plate is This method detects the surface temperature and calculates the surface temperature of the surface to be measured from a first-order correlation.

Further, the temperature sensor for non-contact measurement according to the present invention uses a thin film thermistor that is attached to a sensor head flat plate installed near the surface of the object to be measured and is formed by sputtering on an insulating film formed on a chip substrate. It is something. The conductive wire connected to this temperature sensor and used to measure the resistance of the thin film thermistor is a flexible lead wire formed of copper foil on a polyimide film. In addition, this temperature sensor has a thin film thermistor surface placed on the side to be measured, improving thermal response. In addition, this temperature sensor has a thin film thermistor connected to a flexible lead wire installed in an opening provided in a sensor head flat plate, and the front and back surfaces of the opening in the sensor head flat plate are fixed with adhesive polyimide tape. Furthermore, the above opening is sized so that the copper foil of the flexible lead wire does not contact the sensor head flat plate more than 10 mm from the thin film thermistor, thereby reducing the amount of heat transferred to the sensor head flat plate and improving thermal response. It is something that

Further, the temperature sensor according to the present invention includes a temperature detection section that does not contact the surface of the fixing roller of the rotating body, and a holding member that holds the temperature detection section, which is arranged along the axial direction of the fixing roller,
Both ends of a support member that supports the temperature detection section and the temperature detection section holding member are brought into contact with the bearing or shaft of the fixing roller to regulate the position. Furthermore, a lead wire for transmitting a temperature detection signal extending from the temperature detection section is arranged along the axial direction of the roller.

[Function] In this invention, a sensor head flat plate (temperature detection flat plate) on which a temperature sensor is attached close to the surface of the object to be measured is used.
Since the sensor head is installed, the surface temperature of the 71FJ constant object to be measured can be measured in a non-contact state by measuring the temperature of the sensor head flat plate due to heat conduction of the air layer interposed between the surface to be measured and the sensor head flat plate. In this case, the relationship between the measured temperature of the sensor head flat plate and the temperature of the n1 constant surface to be measured is found to be a linear relationship based on the following considerations, so based on the measurement principle obtained as a result of this consideration, indirect This enables non-contact temperature measurement. The aFJ determination principle described above will be explained below.

FIG. 1 is a schematic explanatory diagram showing the measurement principle of the non-contact thermometer Δ-1 method of the present invention. In the figure, a temperature detection flat plate (also referred to as a sensor head flat plate) 2 equipped with a temperature sensor (not shown) is installed in close proximity (about 0.1 to 2 degrees) to the surface 1 of the object to be measured. Note that 3 is a temperature-like (generally equivalent to room temperature) spatial region.

As shown in Fig. 1, the temperature of such a system in a state of thermal equilibrium is determined by the temperature of the surface 1 of the object to be measured as T8, the nJ constant surface temperature of the temperature detection flat plate 2 as T1, and the temperature of the opposite side as T8. T (generally TA〉A
BT), temperature-like space 3 is T.

Also, the distance from any point along the x-x axis to the plane of temperature Ts is x, and the distance to the plane of temperature T is XA.

S　　　＾ Let the distance to the plane of T be XB.

Now, the heat transfer mechanisms in the system in thermal equilibrium shown in Figure 1 are as follows 1), 2), and 3).

l) It is assumed that heat conduction occurs through an air layer between the constant surface 1 and the temperature detection flat plate 2. When the distance IXs XAl-Xo is small, convection is difficult to occur.

2) The inside of the temperature detection flat plate is a solid heat conductor.

3) Between the top surface of the temperature detection flat plate (XB) and the surrounding space,
Use natural convection.

The steady state heat flow q is expressed by equation (1).

-ho (TB-TE) λ λ h d0 where: λ : Thermal conductivity of the air between the temperature detection flat plate 2 and the measured surface 1 (W/m-k) λ : Thermal conduction of the temperature detection flat plate Rate (W/m-k)ho
: Temperature detection purpose: Heat transfer coefficient (w/m2・k) due to natural convection in the spatial layer on the top surface of the plate (XO) xosm degree detection flat plate 2
Distance d between the surface to be measured 1 and the surface to be measured d: Thickness of the flat plate for temperature detection T 2 Surface temperature of the surface to be measured 1 (''C) ), the temperature on the back side ('C) T: the ambient temperature where the temperature is - ('C) Transforming equation (1), equation (2) is obtained.

x d 1 x.

−＋　　−＋　− Ten - λ h 0 Here, we will simplify using equation 3).

−＋− λd　h.

...(2) α is defined by the following equation.

x d 1 +−+− λ0 λd hO <2), From equation (3), α is the ratio of the thermal resistance of the air layer between the temperature detection flat plate 2 and the surface to be measured 1 to the entire thermal resistance. It is.

FIG. 2 is a diagram showing the temperature distribution along the xx axis in FIG. 1. The horizontal axis is the distance in the X direction, and the vertical axis is the temperature. In the figure, the temperature decreases exponentially with respect to X from TB to TE.

From FIG. 2 and Equation (4), the following things become clear.

- When the surfaces are in contact, α-0 becomes Ts-TA.

- If α is small, it can be considered as Ts-#-TA.

・If α and T are constant, Ts and E are determined by equation (4) A linear relationship holds true with TA.

From the above, the temperature detection flat plate 2 should be covered as much as possible.
It can be seen that if it is installed close to the surface 1 of a fixed object, it is possible to measure the temperature of the surface to be measured without contact.

Further, unlike in the case of a radiation thermometer, the measured temperature T 1 has a linear relationship with the surface temperature T8, so no special correction is necessary, and Ts can be calculated by measuring TA.

In addition to the above, in the temperature sensor of the present invention as described above, since the temperature detection part and the temperature detection part holding member are arranged along the axial direction of the fixing roller, the heat receiving area of each part from the surface of the fixing roller is reduced. expands and improves heat absorption.

Further, since the lead wire extending from the temperature sensing portion is disposed along the axial direction of the fixing roller, the heat receiving area is larger than that described above, the heat absorption rate is improved, and the responsiveness is further improved.

Furthermore, when the support member to which the holding member of the temperature detection section is attached is brought into contact with both ends of the support member to the bearing or shaft of the fixing roller during assembly, the gap between the temperature detection section and the fixing roller is automatically adjusted to a predetermined value. Dimensions.

[Example 1] Hereinafter, an example of a temperature sensor and a temperature detection device for realizing the non-contact thermometer 11 method according to the present invention, and an example of a study experiment to find the optimal conditions for measurement using this temperature sensor will be described. .

[Example] 1; Figures 3(a) and 3(b) are schematic structural diagrams showing an example of a thin film thermistor used in the chip of the temperature sensor of the present invention, and Figure 3(a) is a The plan view and FIG. 3(b) are a sectional view. In the figure, a silicon wafer is used as the chip substrate 4, and an oxide film is formed on the surface to form an insulating film (not shown). The thin film thermistor is formed by sequentially forming an electrode 5 made of a good conductor and an oxide thermistor 6 on this insulating film using photolithography and sputtering techniques. The electrode 4 is formed of comb-shaped electrodes that are interlocked and face each other so that the comb portions do not touch each other, and an oxide thermistor 6 is deposited and covered over the comb portion. . Note that this comb-shaped electrode does not need to be limited to this shape. In this case, the size of the chip board 4 is 3.2×1 with a thickness of 0.525 mm.
．． 8-. A feature of this thin film thermistor is that the temperature sensitive part, that is, the oxide thermistor 6, is extremely thin, approximately 11JI11. Figure 4 is a schematic plan view showing the pattern of the flexible lead wire connected to the thin film thermistor. It is.

Measurement gap XO (
(See Figure 1) It is necessary to use thin film lead wires, and in Figure 4, two copper foils are etched from a copper-clad heat-resistant polyimide film (thickness 25-50mm) 7. A flexible lead wire having a conducting wire 8 formed therein is formed and used.

FIG. 5 is a perspective view showing a state where two electrodes 5 of the chip substrate 4 are bonded to each lead wire of the flexible lead wire 8 by reflow soldering so as to be connected to each lead wire.

This state will be referred to as a temperature sensor in this embodiment. Note that a conductive adhesive may be used as the adhesive.

Next, a method of fixing the temperature sensor shown in FIG. 5 to the sensor head flat plate and installing it close to the surface to be measured will be described.

As shown in the measurement principle diagram of FIG. 1, in the present invention, the temperature detection flat plate 2 prevents air convection and sets the distance from the surface to be measured 1. The flexible lead wire shown in FIG. 4 has a thin structure and is made of flexible material, so it needs to be fixed to the sensor head (temperature detection flat plate).

FIG. 6 is a schematic perspective view showing an example of the structure of the sensor head.

For the sensor head flat plate 21, an SUS plate having high strength and relatively small heat capacity was used. This sensor head flat plate 21 was bent into an L-shape and had a surface for attachment to the frame. As shown in the figure, square openings 21a a, b, c, and d are provided in the sensor head flat plate 21, the chip substrate 4 is fitted into the openings 21a on the surface to be measured, and the flexible lead wires 7 are connected to the sensor head flat plate. Install it on 21. When fixing this flexible lead wire 7, if a thick material is used on the surface to be measured, the chip substrate 4 (
The gap between the temperature sensor) and the surface to be measured increases, and
1) X in the formula. This is not preferable because α in equation (3) increases.

Therefore, in this embodiment, the flexible lead wire 11 with the chip substrate 4 was fixed to the sensor head flat plate 2I with an adhesive polyimide tape 22 having a thickness of 70IJIl. FIG. 7 is a sectional view taken along line A-A in FIG. 6. As shown in the figure, by pasting the polyimide tape 22 around the front and back surfaces of the sensor head flat plate 21, the flexible lead wire 11 with the chip substrate 4 is fixedly attached. Further, the opening 21a is similarly closed with a polyimide tape 22.

Embodiment 2; The temperature sensor of Embodiment 1 was modified depending on how the flexible lead wire 11 with the chip substrate 4 was attached to the sensor head flat plate shown in FIG. 6 and the size of the opening 21a formed by a, b, c, and d. Since the thermal responsiveness is different, in this example, the above 2
We will explain the experimental results of the items.

(2-1) Influence of mounting direction of thin film thermistor Figure 8 (
a) and (b) are schematic cross-sectional views showing two methods of installing a thin film thermistor. Both sensor head flat plate 2
The distance between 1 and the surface to be measured 1 is jll
When the membrane is installed on the surface to be measured, FIG. 8(b) shows the case where the thin film thermistor is installed on the opposite side of the surface to be measured.

The results of determining and comparing the thermal time constant τ in the case of FIG. 8(a) and the case of FIG. 8(b) are shown in the diagram of FIG. 9.

In the figure, the horizontal axis is the gap Xo (in m+s units), and the vertical axis is the thermal time constant τ. Also, a of the diagram in Figure 9,
Curves b correspond to the conditions of (a) and (b) in FIG. 8, respectively, and in both cases the thickness g of the sensor head flat plate 21
shows the case of 0.6 degrees.

As seen in FIG. 149, the installation method shown in FIG. 8(a) has a smaller thermal time constant and is better than the installation method shown in FIG. 8(b). The difference in thermal time constant between FIG. 8(a) and FIG. 8(b) is approximately equal to the difference of N-0.8 times. In other words, in case (b), x is always x for Xo in case (a).
1mxo+1)-xo+0.6w, which means that it is equivalent to an increase in the gap by 0.6mm. In conclusion, as can be seen from the 8 curves in FIG. 9, the thermal time constant τ increases monotonically as Δ)J constant pressure flit (xo) increases. Therefore, aFJ constant distance M(
The structure that can reduce the gap)
It can be seen that it is necessary to choose structure a).

Further, a thin film sensor is preferable because even if the chip substrate 4 is thick, the temperature sensing portion is a thin film on the surface layer, so the thermal response is good. On the other hand, for example, if the diameter is 1 + a
mφ bead-type thermistors and chip thermistors with a thickness of about 0.5 mm have a large temperature sensing part, so they show the average temperature of that thickness, and even if the distance to the surface is the same,
Thermal response is not good because the substantial distance increases.

(2-2) Effect of sensor head opening size 1st O
The figure is a graph showing a comparison of the results of measuring thermal response when the size of the opening 21a of the sensor head flat plate 21 is changed. The horizontal axis of the figure is the measurement distance Xo, and the vertical axis is the thermal time constant τ. Sensor head flat plate 21 on the temperature sensor mounting surface
The size of the chip substrate 4 of the thin film thermistor is 21 mm x 151 mm.
The thickness is 25 ml. The size of the opening 21a is (a)
The sample of (b) is 4 x 4aM, the sample of (b) is 8 x 6-1 (c)
For three types of samples of 8 x 20-, τ with respect to Xo was determined and shown as an A curve, an opening curve, and a convex curve, respectively.

As is clear from FIG. 10, the thermal time constant is the smallest in case (c) where the area of the opening 21a is large, and in this case, even if the measurement distance X6 is 1.0 mm, the thermal time constant is 10 seconds or less, which is the most preferable result. showed that.

The reason for this is thought to be that the heat absorbed by the sensor section is transmitted through the copper foil on the lead wire and absorbed into the sensor head flat plate 21, which reduces the temperature rise rate of the thin film thermistor, which is the temperature sensing section. In the case of (c), the opening 21a is made larger and the distance L (see Figure 10 (c)) for the copper foil lead wire to reach the SUS board is set to more than l Oam, which reduces heat loss. This is thought to be due to an improvement in thermal responsiveness.

Further, for the above reasons, it is concluded that keeping the cross-sectional area of the copper foil to a size necessary for measuring the resistance of a thin film thermistor and making it as small as possible is useful for improving thermal response.

Embodiment 3; FIG. 11 is a schematic explanatory diagram of a non-contact thermometer n1 means showing an embodiment including a measuring circuit system of the present invention.

In this example, the temperature sensor shown in Example 1 was fixed to the frame of a copying machine, and the surface temperature of the fixing roll of the copying machine was measured in a non-contact mode.

In the figure, the surface of a fixing roll 19 that is fixed to a frame 27 of a copying machine (not shown) and rotates and moves so that the sensor head flat plate 21 on which the chip substrate 4 is attached can be set close to the surface of the fixing roll la to be measured. Measure temperature. Temperature detection is performed by a temperature detection circuit 23 using the output of a thin film thermistor formed on the chip substrate 4, and the output is input to a temperature display 24 or a temperature control circuit 25.

The output of this measured temperature is used as a control signal to control the electric power of the electric heater 26 in the fixing roll la to maintain the temperature of the fixing roll la at a predetermined value.

Conventionally, a thermistor was used in contact to detect the temperature of the fixing roll of a copying machine, but the present invention enables non-contact measurement. Further, since there is no difference in output characteristics, the temperature detection circuit 23 is simple and can be configured by a combination of conventional techniques, since a conventional thermistor temperature detection circuit can be used as is.

The most popular example of a thermistor-based thermometer a1 is an electronic thermometer. An electronic thermometer converts the resistance change of the thermistor into a frequency, stores the relationship between frequency and temperature in an IC, and converts the temperature. Thermistor temperature conversion IC is
These ICs are already commercially available, and inexpensive temperature display can be easily achieved using these ICs.

Note that although a thin film thermistor is used in this example,
It goes without saying that thin film temperature resistors, thermocouples, etc. can also be used as temperature sensors.

Example 4: A basic experiment was conducted on non-contact temperature measurement according to the present invention, and feasibility was investigated based on the results. Measurement experiments were carried out using the sensor head of the sample (c) in the example shown in FIG. 10 as the temperature sensor, and a temperature-adjustable hot plate as the PJ constant surface.

FIG. 12(a) is a diagram based on experimental values showing the relationship between measured distance and temperature indication value, and the horizontal axis is measured distance X. , the vertical axis is the commanded temperature T^. The temperature of the contact type surface thermometer of the hot plate, that is, the surface temperature T3 - Measured distance X while maintaining the temperature at 170 to 172°C. 0.2 to 1. The final indicated temperature TA when the temperature changes by Om+e is determined. Note that the ambient temperature, ie, T6, is 25°C. TA continues to decrease monotonically as X increases.

FIG. 12(b) is a diagram based on calculated values showing the relationship between the thermal resistance ratio of the air layer and the indicated temperature, where the horizontal axis is the thermal resistance α and the vertical axis is the indicated temperature TA. As the calculation formula, the formula T-(1-α)Ts+αTE, which is a modification of formula (4), was used. As in the case of Fig. 12(a), T s -17Ω℃, T E-2
The value of TA is plotted when the temperature is set at 5°C and the temperature is varied from α-0 to 0.2.

From the diagrams in Figures 12(a) and (b), Figure 12(a)
), the relational expression (4) almost holds true, and (4)
This shows that the application of the formula is valid. It can be seen from the drawing that x om 0.55 mm corresponds to α-0.1.

FIG. 13 is a so-called correction curve diagram showing the relationship between the measured temperature and the indicated temperature, where the horizontal axis is the surface temperature T8 and the vertical axis is the indicated temperature TA. In the figure, the - dotted chain line indicates that TA and Ts are 1.
Standard curve for comparison with a slope of 45°C corresponding to :1.

The experimental conditions were x g −0, 55! Set the temperature sensor on II@, and set the hot plate temperature, that is, Ts, to 25~2
The indicated temperature TA was determined when the temperature was changed to 00°C. In the figure, the solid line represents the equation TA-(1-α)
This is a calculated value curve using T + αTE (α-0, t 5TE-25°C). The X mark indicates the measured value.

As can be seen from the experimental results in Figure 13, T8-25 to 20
In the range of 0℃, the output characteristics are linear and the accuracy is ±
The temperature was approximately 2° C., and satisfactory measurement results were obtained as expected.

Also, from this result, it is clear that this invention is particularly effective in the low temperature range (0 to 2
00°C). In other words, non-contact temperature measurement methods based on principles other than radiation thermometers, which have been the mainstream of conventional non-contact temperature measurement methods, have not been put into practical use, whereas the non-contact temperature measurement method using a temperature sensor according to the present invention 7 of the low-temperature part that radiation thermometers are particularly weak at, especially accuracy warehouses.
This enables highly accurate measurement in the #1 temperature range, and this point can be said to be the most significant feature of the present invention.

As a conclusion of Examples 1 to 4 explained above, the copper foil portion of the flexible lead wire is as large as possible (10 m+s or more in the example) using a temperature sensor that has an opening exposed to the surface to be measured. as close as possible to the surface (0
, 5 fins) and installing the temperature sensor is the optimum condition for the non-contact temperature measurement method according to the present invention.

Embodiment 5; FIGS. 14 and 15 are schematic diagrams showing a fixing device of, for example, an electrophotographic copying machine equipped with a temperature detection device using a non-contact temperature sensor of the present invention, and FIG. FIG. 15 is a sectional view of the main part and a side view.

In both figures, 31 is a temperature detection section mainly composed of a temperature sensor, 32 is a holding member thereof, 33 is a support member (for example, a bracket) for attaching the holding member 32, 34 is a fixing roller,
35 is a heater provided inside, 35a is a heater outer frame, 36 is a pressure roller, 37 is a fixing cover 38 is a machine frame,
80, 81, and 62 are guide plates, 34 is a peeling claw, 40 is a bearing that supports the fixing roller 34 on the machine frame 38, and 41 is a gear attached to the fixing roller shaft. Note that in FIG. 15, a description of the drive mechanism of the pressure roller 36 is omitted.

In FIGS. 16 and 17, the temperature detection section 31 is connected to the holding member 32.
FIG. 16 is a side view and FIG. 17 is a perspective view thereof. In both figures,
A temperature sensing portion 31 is attached to the lower end of the holding member 32, and the holding member 32 is made of, for example, a stainless steel plate and extends along the axial direction of the fixing roller 34, and a pair of upright pieces 42 are provided on the front and rear sides thereof. This upright piece 42 is provided with a vertically long hole 43.

The holding member 32 has a black coating formed on at least the surface facing the fixing roller 34 . Note that 44 is a lead wire connected to the temperature detection section 31.

FIG. 18 and FIG. 19 are detailed structural explanatory diagrams of the mounting part of the temperature sensing part 31 to the holding member 32, and
8 is a side sectional view, and FIG. 19 is a sectional view taken along the line A-A shown in FIG. 18. In both figures, 5.45 is a substrate made of a polyimide film, 46 is a current carrying part, 47 is a thin film thermistor, 48 is an insulating film made of a polyimide film, 49 is a protective film made of a polyimide film, and the current carrying part 4B has a 16th As shown in the figure, a lead wire 44 is connected, and this lead wire 44 transmits a temperature detection signal from the temperature detection section 31 to a temperature control section (not shown), and is arranged along the axial direction of the fixing roller 34. . Note that as the temperature sensor, a conventional glass-enclosed type thermistor may be used instead of the thin film thermistor 47.

FIG. 20 shows a state in which the holding member 32 is attached to the support member 33. This support member 33 extends along the axial direction of the fixing roller 34, and a hanging plate 50 is provided on each side edge in the axial direction. The upright piece 4 of the holding member 32 is located approximately in the middle of the hanging plate 50 of the supporting member 33.
2, the tip of the hanging plate 50 is brought into contact with the surface of the holding member 32, one side of the upright piece 42 and the hanging plate 50 are fixed with a screw 52, and the other side is stopped with a stepped screw. do.

FIG. 21 shows an example in which the tapped holes 53 of the support member 33 are formed by punching.

When attaching the support member 33 to which the holding member 32 is attached in this way to the fixing device, the support member 33 is arranged along the axial direction of the fixing roller 34 as shown in FIG. The lower portions of both ends are brought into contact with the bearings 40 of the fixing roller 34 for automatic positioning, and thus arranged, the upright piece 54 of the support member 33 is fixed to the machine frame 38 with screws 30a. Note that the support member 33 and the holding member 32 may be integrally formed by casting or sheet metal processing.

Although not shown, both ends of the hanging plate 50 may be positioned by directly contacting the shaft of the fixing roller 34.

In this way, since the lower parts of both ends of the hanging plate 50 and the position where the temperature sensing part holding plate is pressed and stopped are on the same plane, the processing accuracy is very high, and the positioning of the temperature sensing part with respect to the fixing roller is made easy. Ta.

FIG. 22 is a plan view showing another embodiment of the temperature sensor according to the present invention. In the figure, 33°45.4B
, 47 and 49 are the parts shown in the above embodiment, and their explanation will be omitted. A thin film thermistor 47 as a temperature sensor is installed at one end of the current-carrying part 4B formed on the polyimide substrate 45.
Further, a lead wire 44 is connected to the opposite end via a soldered portion 55. Note that the protective film 49 has a thickness of 3 here.
0- Kapton tape is used. As for the dimensions of this temperature sensor, the width W can be formed to be at most 14 m11.

As described above, in the fixing device having the temperature sensor assembled as shown in the fifth embodiment, the lower portions of both ends of the support member 33 come into contact with the bearings 34, so that the temperature detection unit 31 and the fixing unit are connected to each other. The distance between the rollers 34 remains constant without the need for complicated adjustment operations, and such a fixing device then performs the desired adjustment operation in exactly the same way as a conventional fixing device. The gap between the fixing roller 34 and the thermistor unit is preferably 0.2 to 2, and within this range, the temperature control of the fixing roller is sufficiently satisfactory. In this embodiment, it is 1±0.2+++II. It should be noted that the present invention is not limited to the above embodiments, and it goes without saying that the rotating body that is the object to be temperature detected may be a rotating body other than a constant volume roller.

[Effects of the Invention] As described above, according to the present invention, a flat plate equipped with a temperature sensor is installed near the surface of an object to be measured, and the surface temperature transmitted through the thermal conduction of the air layer of the flat plate is detected. By providing a contact temperature measuring method for estimating the surface temperature of a surface to be measured and a temperature sensor that is most suitable for the method, it has the features listed below, and many effects based thereon can be obtained.

(2) The indicated (measured) temperature and the surface temperature are in a linear relationship, which is simple, and the totalization 111 is performed with good linearity. Does this mean that radiation thermometers have different output characteristics depending on the method? Although it is a UI, it has great advantages in terms of measurement performance compared to the UI.

2) Since the thermal resistance of the air layer is the only disturbance factor, another method is to use a meter that is not affected by the surface condition, that is, the thermal emissivity.

3) Since the temperature sensor is small and can be made thin, non-contact operation in narrow spaces is also possible. For example, in the case of a heat-sensitive roll of a copying machine, a sensor head of the same size as a conventional contact-type surface temperature sensor can be applied.

4) Since the measurement principle is thermal conduction, there is no decrease in sensitivity even in the temperature measurement range close to room temperature, for example, in the range of -50 to 200°C. On the other hand, with the radiation thermometer method, it is difficult to measure with high accuracy near room temperature, including the selection of the detector.

5) When a thin film thermistor is used as the temperature sensor in the detection circuit, the conventional thermistor circuit technology can be used as is, making it possible to achieve an inexpensive total of n1. The reason for this is that thin film thermistors have similar temperature-resistance characteristics (B
This is because it has a constant).

6) Since it provides an inexpensive non-contact temperature measurement method, its uses are extremely wide. For example, the following application fields are applicable.

・Temperature measurement of rotating rolls of office automation equipment, such as copying machines.

・Temperature measurement inside rotating mechanisms such as motors.

・Non-contact temperature measurement in the manufacturing process of paper, cloth, metal plates (steel plates, etc.), surface treatment processes, etc.

・Surface temperature measurement of rolls used in industrial processes.

7) In non-contact temperature measurement, both the #1 object and the detection part are not damaged. This is expected to have immeasurable effects in the consumer and industrial fields.

Further, in the temperature sensor according to the present invention, since the temperature detection part and the temperature detection part holding member are arranged along the axial direction of the fixing roller, the heat receiving area of each part from the surface of the fixing roller is expanded. The improved absorption rate improves the thermal response, and since the lead wire extending from the temperature detection section is arranged along the axial direction of the fixing roller, the amount of heat that escapes due to heat conduction at the temperature detection section is reduced. This decrease improves the heat absorption rate of the heat measurement system and further improves the thermal response. Further, since the black film is provided on at least the surface of the holding member of the thermistor unit facing the fixing roller, there is an effect that the heat absorption rate is improved and the thermal response can be improved.

Furthermore, since the temperature sensing section is attached to a holding member and both ends of the supporting member to which this holding member is attached are in contact with the bearing or shaft of the fixing roller, the position of the temperature sensing section with respect to the fixing roller is regulated. is automatically determined by the contact between the support member and the bearing or shaft, which not only simplifies the assembly work but also provides extremely high accuracy.

[Brief explanation of drawings]

Fig. 1 is a schematic explanatory diagram showing the measurement principle of the temperature measuring method of the subject of contact according to the present invention, Fig. 2 is a diagram showing the temperature distribution along the x-x axis in Fig. 1, Fig. 3 (a), ( b) is a schematic structural diagram showing one embodiment of the temperature sensor of the present invention, and FIG.
) is its plan view, FIG. 3(b) is its cross-sectional view, FIG. 4 is a schematic plan view showing the pattern of the flexible lead wire, and FIG. 5 is a perspective view showing the state in which the chip board is bonded to the flexible lead wire. , FIG. 6 is a perspective view showing an example of the configuration of the sensor head, and FIG. 7 is a sectional view taken along line A-A in FIG. 6.
FIGS. 8(a) and 8(b) are schematic cross-sectional views showing two methods of installing a thin-film thermistor, and FIG. 8(a) is a cross-sectional view when the thin-film thermistor film is installed on the surface side of the object to be measured.
Figure 8(b) is a cross-sectional view when installed on the opposite side of the surface of the object to be measured, Figure 9 is a diagram comparing the thermal time constants depending on two mounting methods of the thin film thermistor, and Figure 1O is 11 is a diagram comparing the influence of the size of the opening of the sensor head on the thermal time constant; FIG. Figure (a) is an experimental value diagram showing the relationship between flllJ constant distance (gap) and temperature indication value, and Figure 12 (b) is a calculated value showing the relationship between the thermal resistance ratio of the air layer and temperature indication value. 13 is a diagram of a correction curve showing the relationship between the non-7iIJ constant temperature and the indicated temperature, FIG. 14 is a schematic front view of a fixing device equipped with the temperature sensor of the present invention, and FIG. 15 is the same as above. Partially cutaway side view, 1st
6 is a front view of the holding member of the temperature detection part of the temperature sensor of the present invention, FIG. 17 is a perspective view of the same as above, FIG. 18 is an enlarged sectional view of the part surrounded by the circular curve in FIG. 16, and FIG. 19 The figure is a sectional view taken along the line A-A in FIG. 18, FIG. 20 is a side view of the temperature sensor holding member of the present invention attached to a support member, and FIG. 21 is a part of an example of the same support member. Slope view of
FIG. 22 is a plan view showing another embodiment of the temperature sensor. In the figure, 1 is the surface of the non-measured object, 1a is the fixing roll,
2 is a flat plate for temperature detection (sensor head flat plate), 3 is a temperature detection plate
4 is a chip substrate (silicon wafer with oxide film), 5 is an electrode, 6 is an oxide thermistor, 7 is a polyimide film, 8 is a conductor (copper foil), 11 is a flexible lead wire, 21 is for temperature detection Flat plate, 21a is an opening, 22
2 is a polyimide film, 23 is a temperature detection circuit, 24 is a temperature indicator, 25 is a temperature control circuit, 26 is an electric heater, 2
7 is a frame, 31 is a temperature detection section, 32 is a holding member, 3
3 is a support member, 34 is a fixing roller, 38 is a machine frame, 40 is a bearing, 42 is an upright piece of the holding member 32, 44 is a lead wire, 47 is a thin film thermistor, 50 is a hanging bell, 50 is a support member 33 It is a standing piece of.

Claims (11)

[Claims] (1) A temperature detection flat plate equipped with a temperature sensor is installed near the surface of the object to be measured, and the air layer between the temperature detection flat plate and the surface of the object to be measured is A non-contact temperature measurement method, characterized in that the temperature of the surface of the object to be measured is measured from the temperature detected by the temperature detection flat plate using a linear function derived using thermal resistivity as a parameter. (2) In a temperature sensor for non-contact temperature measurement, it is attached to a temperature detection flat plate installed near the surface of the object to be measured,
A temperature sensor characterized by using a thin film thermistor, which is a thermistor formed on an insulating film formed on the surface of a chip substrate. (3) The temperature sensor according to claim 2, characterized in that a flexible lead wire connected to the electrode of the thin film thermistor and formed of copper foil on a polyimide film is used as the conducting wire. (4) The temperature sensor according to claim 2 or 3, wherein the chip substrate surface side on which the thin film thermistor is formed is installed on the surface side of the object to be measured. (5) An opening is provided in the temperature detection flat plate, the thin film thermistor connected to the flexible lead wire is installed in the opening, and the front and back surfaces of the opening are fixed with adhesive polyimide tape. The temperature sensor according to claim 3. (6) The temperature sensor according to claim 5, wherein the opening has a size such that a portion of the copper foil constituting the flexible lead wire is exposed on the surface side of the object to be measured by 10 mm or more from the thin film thermistor. . (7) In a temperature sensor that detects the surface temperature of a rotating body, which is an object to be measured, it is attached to a flat plate for temperature detection, and is installed in a non-contact manner to the rotating body surface and approximately parallel to the rotating body axis direction. Characteristic temperature sensor. (8) The temperature sensor according to claim 7, wherein the temperature detection flat plate is provided substantially parallel to the axial direction of the rotating body. (9) The temperature sensor according to claim 7, wherein a lead wire for transmitting a temperature detection signal extending from the temperature sensor is disposed in the axial direction of the rotating body. (10) In a temperature sensor that detects the surface temperature of a rotating body, which is an object to be measured, it is arranged in the direction of the rotating body axis, and both ends are supported by a rotating body bearing part or a support member that comes into contact with the rotating body axis. Characteristic temperature sensor. (11) The temperature sensor according to claim 10, wherein the support member is integral with the temperature detection flat plate.