JPH02197908A - Heater temperature controller - Google Patents

Abstract

PURPOSE:To suppress the overshoot value of the heater temperature by controlling the driving duty of energization at a level less than the target value in accordance with the rising slope of the heater temperature. CONSTITUTION:The duty is set at 100% when the drive is started and therefore the ability of a heater 1 can be applied to its maximum level where the temperature of the heater 1 is approximate to the target value T0. Then the driving duty of energization is controlled for the heater 1 in accordance with the rising slope DELTAT of the hitherto heater temperature at the temperature of the heater 1 approximate to the value T0. Thus the ability of the heater 1 is controlled. As a result, the time required for the rise of the heater temperature is minimized and at the same time the temperature overshoot value is suppressed.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a heater temperature control device that controls a heater drive duty so that a detected value of heater temperature becomes a target value.

[Prior Art] Generally, as a heater temperature control device for controlling the temperature of the heater to a target value, for example, Japanese Patent Application Laid-Open No. 145310-1983
There is something disclosed in the publication No.

This conventional device is provided with heater temperature detection means, the detected value is compared with a reference value, and the heater is turned on and off based on the comparison result.

Incidentally, an intervening object such as a structural material is usually located between the heater and the temperature detecting means.

Since the detection element of the temperature detection means has a heat capacity, a delay time of several seconds to several tens of seconds is required after the temperature of the heater changes until the temperature of the temperature detection means changes.

Therefore, in the conventional device described above, when the temperature rises, the heater temperature always overshoots the target value.

In order to suppress the effects of such heater temperature overshoot, measure the amount of overshoot in advance and develop a capability that corresponds to the amount of overshoot.

Just select a heater.

[Problems to be Solved by the Invention] By the way, when a device using a heater is used in multiple countries, the above-mentioned conventional device has the following disadvantages.

In other words, each country has its own power supply situation.
The center value and fluctuation range of the power supply voltage are different.

Therefore, if the heater is used under power supply conditions that are significantly different from the conditions under which the heater is used, the amount of overshoot in the heater temperature will be excessive, causing the plastic structural materials around the heater to melt or protect the heater. This may cause inconveniences such as disconnection of temperature fuses and thermostats.

An example of a method for solving this problem is disclosed in Japanese Patent Application Laid-open No. 150279/1983. :' - This device detects the power supply voltage and drives the conduction of the heater with a duty corresponding to the detected value.

However, in this device, since the power supply capacity is not fully utilized, a disadvantage arises in that it takes a long time to raise the heater temperature to the target value. Furthermore, since a means for detecting the power supply voltage is required, the device and configuration become larger and the cost becomes higher.

In view of these circumstances, the present invention has been devised to reduce the time required to raise the heater temperature to the target value, and reduce the cost. The present invention has a gradient detection means for detecting the temperature rise gradient of the heater, and a method for driving the heater at a duty rate of 100% when starting the heater drive. However, when the heater temperature reaches a specified value lower than the target value, the heater temperature rises. The apparatus includes a reference signal generating means for generating a reference temperature signal based on the gradient.

[Action...
Therefore, the drive duty of energization is adjusted before the target value in accordance with the temperature rise gradient of the heater, so that the overshoot amount of the heater temperature can be suppressed. Further, since the duty is set to 100% at the start of driving, the power supply capacity can be fully utilized, and the time required for the heater temperature to reach the target value can be significantly shortened. Further, since the reference temperature signal for controlling the on/off of energization of the heater is set in accordance with the temperature increase gradient of the heater, the amount of overshoot of the heater temperature can be suppressed. - [Example] Hereinafter, an example of the present invention will be described in detail with reference to the accompanying drawings.

FIG. 1 shows a heater temperature control device according to an embodiment of the present invention.

In the same figure, a detection signal ST of a temperature detector 2 for detecting the temperature of a temperature sensor 2 is applied to a comparison input terminal of a comparator 3 and a temperature control section 4.

A temperature reference value VR corresponding to the magnitude of the detection signal ST when the temperature of the heater l is at the target value is applied to the reference input terminal of the comparator 3, and the comparator 3 is connected to the reference input end of the comparator 3. - When the magnitude of the detection signal ST exceeds the temperature reference value VR, the output signal LO is lowered to the logic L level.

In other cases, the logic level of the output signal LO is set to the logic H level. This output signal LO is applied to one input terminal of the AND circuit 5.

The temperature control unit 4 determines the gradient of temperature rise of the heater 1 based on the change in the detection signal ST, and adjusts the energization drive duty of the heater 1 based on the determination result, and adjusts the energization drive duty. A duty command signal DT corresponding to the duty command signal DT is output to the duty modulation circuit 6.

...: The duty modulation circuit 6 generates a duty heater drive pulse signal DD based on the duty command signal DT applied from the temperature control section 4, and the heater drive pulse signal DO is sent to the AND circuit 5. is added to the other input end.

The output signal of the AND circuit 5 is applied to the heater drive circuit 7 as a heater drive signal DV.

The heater drive circuit 7 energizes the power source 8 to the heater 1 when the heater drive signal DV is at a logic H level.

With the above configuration, when the heater 1 starts being energized, the temperature control section 4 outputs the duty command signal DT corresponding to the duty of 100% to the duty modulation circuit 6.

As a result, the duty modulation circuit 6 outputs the heater drive pulse signal DD that maintains the logic H level for the pulse width TMI, as shown in FIG. 2(a).

Also, at this time, the temperature of the heater 1 is approximately room temperature, so the detection signal ST of the temperature detector 2 is
The temperature is smaller than the temperature reference value VR, so that the output signal LO of the comparator 3 is at the logic H level, and the AND circuit 5 is in an operable state.

Therefore, the AND circuit 5 outputs the heater drive pulse signal DD to the heater immediate action circuit 7 as the heater drive signal DV.
is output to.

As a result, the power source 8 is continuously supplied to the heater 1,
As a result, the temperature of the heater 1 rises at a constant gradient, as shown by a graph 61 in FIG.

Here, the temperature control unit 4 monitors the detection signal ST output from the temperature detector 2, and the temperature of the heater 1 is set to a specified value T.
Measure the time TA until it changes from 1 to the specified value T2,
Based on that time TA and temperature difference (T2-T),
Calculate T to the gradient of temperature rise of heater l.

Then, based on the gradient ΔT, a temperature lower than the target value T0 is calculated as the specified value T, and further, when the temperature of the heater 1 reaches the specified value T, the temperature control unit 4 calculates the slope calculated at that time. The duty corresponding to ΔT is determined, and the determination result is set as the duty command signal DT.

As a result, from then on, the duty of the heater drive pulse signal DD output from the duty modulation circuit 6 is changed to the value set by the duty command signal DT.

At this time, for example, if the duty is set to 50%, the AND circuit 5 outputs a heater drive signal DV with a duty of 50% as shown in FIG. 2(b).
Thereby, the heater drive circuit 7 supplies the power source 8 to the heater 1 with a duty of 50%.

As a result, the temperature of the heater I increases at a gradient corresponding to the energization drive duty of 50% immediately after passing the specified value T.

Then, when the temperature of the heater 1 exceeds the target value T0, the output signal LO of the comparator 3 becomes the logic L level, so the AND circuit 5 becomes inactive. Thereby.

The heater drive signal DV is a signal that maintains the logic L level.

As a result, the heater drive circuit 7 no longer supplies power 8 to the heater 1, and the temperature of the heater 1 gradually decreases.

Then, the temperature of the heater 1 is the target value T. When the output signal LO of the comparator 3 becomes a logic H level, the AND circuit 5 becomes operable and the heater drive pulse signal DD is applied to the heater drive circuit 7 as the heater drive signal DV.

Thereby, the heater drive circuit 7 supplies the power source 8 to the heater 1 with a duty of 50%.

From this point on, the temperature of heater I is the target value T. The temperature of the heater 1 is thereby controlled to the target value T0.

The temperature control unit 4 controls the temperature difference so that when the calculated gradient T of temperature rise is large, the temperature difference from the target value T11 becomes larger, and when the gradient T is small, the temperature difference from the target value To is The specified value T3 is set so that the temperature difference becomes smaller.

Further, when the calculated gradient ΔT of temperature rise is large, the temperature control unit 4 sets a smaller duty to the duty command signal DT, and when the gradient T is small, sets a larger duty to the duty command signal DT. Set to .

For example, when the temperature of the heater 1 rises at T to a slope smaller than that of the graph G1, as shown in graph G2 shown by a dashed line in FIG. Duty, for example, 6 brocades, specified value T
, is set as the duty when it exceeds.
... , ■Therefore, in the case of heat, if the specified value is exceeded, the second
A heating/active signal DV as shown in FIG. 3(c) is applied, whereby the heater I is energized with a duty of 6.

゛Also, the relationship between the gradient ΔT of the temperature rise on Tanabata 1 and the specified value T3, and the energization of the heater 1 when the gradient ΔT and the temperature of the heater 1 exceed the specified value. The relationship between the driving units 5 and 1 can be determined using real numbers for each device. However, the cycle of the heater immediate pulse signal, that is, the pulse width T, is set to a value that does not cause noise, for example, several seconds.
,' in this embodiment, the heater l
The heater capacity is maximized until the target temperature approaches the target value T0, and when 1 degree of the heater 1 approaches the target value T0, the heater 1 Since the power supply duty of the heater 1 is adjusted to adjust the capacity of the heater 1, the time required for the temperature of the heater 1 to rise can be minimized, and the amount of temperature overload can be suppressed.

In addition, following the power supply 8 whose voltage is within the rated range of the heater 1,
Since this can be done without changing the device configuration, the mass production effect is large and the cost of the heater temperature control device can be reduced.

FIG. 4 shows an implementation example of the apparatus shown in FIG.

In FIG. 4, the same parts and corresponding parts as in FIG. 1 are given the same reference numerals.

In the figure, the thermistor 11 has a resistance value that changes depending on the temperature of the heater l, and the thermistor 11 and the resistor 12 are connected in series.

The terminal voltage signal of the thermistor 11 is applied to the comparison input terminal of the comparator 3 and the can-chip microcomputer 13 as the temperature detection signal ST of the heater l. □ The one-chip microcomputer 13 receives the detection signal S
An analog/digital converter 14° that converts T into a corresponding digital signal □ (hereinafter referred to as temperature data) O5, and a microcomputer that realizes the functions of the temperature control section 4 and the duty modulation circuit '6. It is composed of 15. □ , ·: : Also, solid state Riruni: "16 is applied to the heater 1 when the heater word signal DV outputted from the AND circuit 5 is at the logic H level.

The comparator 3 is a device that stops the output l of the power supply 8 when the heater oscillation signal DV is at logic level t. The temperature reference value VR is determined by voltage dividing resistors 19, 204, . − is formed □.

Micro combination kneader 1 corresponding to the function of temperature control section 4
An example of processing No. 5 is shown in FIG. 5:'.

...When increasing the temperature of heater 1, first, flag FL
GI, FLG2 reset processing 101), duty value D to instruct the functional processing of the duty modulation circuit 6
As soon as N is initialized to 100% (processing 1d2), temperature data O5 is input (processing 103). Check whether it is (Judgement 104), and
When the result of step 4 is YES, the temperature of the heater 1 is lower than the specified value T, so the process returns to step 103.・
' □ j □When the result of judgment/judgment 104 is NO, flag F is set.
Check whether LGI is set (Judgment 10)
5), '1...: '□When the result of judgment 105 is ~01, this means that the temperature of heater 1 has risen and exceeded the specified value T, so the temperature of heater 1 is As soon as the value increases from the specified value T1 to the specified value T2, the slope monitor for measuring the 9' time of the dice is activated, the flag F"LGI is set (process 107), and the xo3'&, -': Return.

::When the result of 11th judgment 11os is YES, check whether the temperature data DS is below the specified value T2 (Judgment □Decision 108), and the result of Judgment 108 is '
/ES is a case where the temperature of heater 1 has risen from the specified value T to the specified value T2, so process 103 is performed.
Return to

When the result of □ judgment 108 is NO, it is checked whether flag FLG2 is set (judgment 109).

When the result of the judgment 109 is NO, it means that the temperature of the heater 1 has increased and exceeded the specified value T2, so the slope timer is stopped (step 110), the timed value of the slope timer is saved, and the specified value is Process 111 to calculate the value T3
), sets flag FLG2 (process 112), and returns to process 103.

When the result of judgment 109 is YES, it is checked whether the temperature data DS is below the specified value T (judgment 113), and when the result of judgment 11i'l13 is '/ES, the temperature of heater 1 is From specified value T2 to specified value T3
Since this is the case, the process returns to step 103.

When the result of judgment 113 is No, the heater 1 corresponding to the time value saved in process 111 is determined by a predetermined calculation.
The energization drive duty is determined (process 114), and the energization immediate action duty is set to the duty value ON (process 115), and this process ends.

In this way, the microcomputer 15 determines the slope of the temperature rise of the heater l based on the temperature data DS, and based on the determined value of the slope, determines whether the temperature exceeds the specified value T3 or not. It is calculated by calculating the duty when

Note that the microcomputer 15 stores in advance the relationship between the slope determination value and the specified value T3, and the relationship between the slope determination value and the energization drive duty.

A processing example of the microcomputer 15 corresponding to the function of the duty modulation circuit 6 is shown in FIG.

First, when the heater 1 starts to be driven, FIG.
As shown in (C), set the duty timer start flag FLGD to start the duty timer for timing the pulse width TMI of the heater drive pulse signal DD and the pulse IliTM2 of the logic H level portion. Process 201), duty timer timer value DTT
(processing 202), and the heater opening pulse signal D
Set data rlJ to D, and apply heater drive pulse signal D.
D is raised to logic H level (process 203).

Then, wait until the timer value DTT of the duty timer becomes a value corresponding to the pulse width TM2 corresponding to the duty value DN (No loop of judgment 204), and when the result of judgment 204 becomes YES, the heater opening pulse signal DD is set to data "0" to lower the heater drive pulse signal DD to logic L level (processing 205), and waits until the timer value DTT of the duty timer reaches a value corresponding to the pulse width TMl (judgment 205). .

As a result, when one generation of the heater drive pulse signal DD is completed, it is checked whether the heater immediate action has ended (determination 207), and when the result of determination 207 is NO,
Return to process 202. Further, when the result of determination 207 is YES, this process is ended.

In this way, the duty is (T
A heater drive pulse signal DD of M2/TMI)% is formed and applied to the AND circuit 5.

FIG. 7 shows an example of duty timer processing.

This process is a timer interrupt process that is executed every time a reference pulse that is generated in a certain short period of time is applied. When the result becomes YES, the timer value DTT is incremented (process 302), and this process ends.

Further, when the result of determination 301 is No, this process is ended without incrementing the timer value DTT.

As a result, when the duty timer activation flag FLGD is set, each time a certain period of time elapses,
The duty timer value DTT is incremented, thereby making it possible to know the elapsed time since the duty timer value DTT was cleared.

By the way, in the embodiment shown in FIG. 4, the thermistor 11 used to detect the temperature of the heater 1 has relatively poor temperature detection accuracy.

Therefore, in order to measure the gradient of temperature rise of the heater 1, it is necessary to secure a certain amount of space between the specified value T and the specified value T2, and in order to suppress the amount of overshoot, it is necessary to maintain the specified value T3. It is necessary to ensure a sufficient temperature difference between the target value T0 and the target value T0.

On the other hand, when the heater 1 is activated, the temperature of the heater 1 is not necessarily lowered to room temperature.

Therefore, if the temperature at startup of heater 1 is not a sufficiently low value, the value calculated during the previous process may be used as is as the energization drive duty when the temperature of heater 1 exceeds the specified value T. Alternatively, use the default value preset on the device.

Further, the specified value T3 in this case is set to a temperature that does not overshoot even with the gradient of the previous temperature rise, or is set to a temperature lower than the target value TII by a temperature difference corresponding to the energization drive duty to be used. That is, the specified value T3 in this case becomes the default value.

Note that these default values are appropriately set depending on the power supply characteristics and equipment used.

Incidentally, in the above-described embodiment, the temperature control section and the duty modulation circuit are implemented in software using a one-chip microcomputer, but this implementation means is not affected by this.

Furthermore, in the above-described embodiments, a thermistor is used as the temperature detector of the heater, but other temperature detectors may also be used. In addition, if a heater with a temperature detection function is used, there is no need for a temperature detector.
A fixed value can also be used as the specified value T3.

Now, in the embodiment described above, the amount of overshoot of the heater temperature is suppressed by changing the duty of energization according to the temperature rise gradient of the heater. A similar effect can be obtained by changing the reference temperature for turning on and off, and next, such an example will be described. Also,
In this case, for example, as shown in No. 81i1, a heater that heats the fixing roller of the copying machine will be described.

That is, the heater 1 is built into the fixing roller 21, and the fixing roller 21 is pressed against the pressure roller 22. Pass the recording paper 23 on which the toner image has been transferred between the fixing roller 21 and the pressure roller 22.
In this way, the toner image is fixed on the recording paper 23.

As shown in Figure Hayabusa 9, the heater 1, which has been preheated to a thermal temperature Ta, is energized at time t, and energized at time t when the heater temperature reaches the reference temperature Tr. When turned off, the temperature/degree rise of the heater l stops at the peak temperature Tp at time 1t after a delay time td has elapsed from time t (overshooting), and thereafter the temperature of the heater l decreases.

Here, the temperature Tb indicates the lower limit value of the fixing temperature, and the temperature Tb
c indicates the allowable limit temperature of the mechanisms surrounding the heater, such as the fixing roller 21.

Now, the delay time td can be obtained experimentally, and using this delay time td, the peak temperature τp can be calculated using the linear formula % formula % where a is the temperature rise gradient of the heater 1. Squirrel.

In order to prevent the heater temperature from exceeding the allowable limit temperature Tc due to an overshoot in the temperature rise of the heater 1,
Peak 117! The reference temperature Tr may be set so that the following equation (■) holds true for Tp4C.

Tp 5 Tc - (Ti) Based on these equations (1) and (n), the reference temperature Tr is defined by the following equation (III).

Tr = τc - a rumor t4 On the other hand, if the relationship between the surface temperature T of the fixing roller 20 and the detection signal ST of the temperature detector is T = f (ST), then the above equation (III) is It can be rewritten as the following formula (IV).

Therefore, in this case, the reference temperature signal Vr is a function of the temperature increase gradient a, as shown in FIG. , respectively as shown in the following formula (V)*(VX).

Vr=f(Ts) d,=(Tc-Ts)/td□...(V)...(Vl) FIG. 11 shows the heater temperature control device according to this embodiment. In this figure, the same or corresponding parts as in FIGS. 1 and 16 are designated by the same reference numerals.

The detection signal ST of the temperature detector 2 is applied to the comparison input terminal of the comparator 3 and is also applied to the -temperature rise gradient detection circuit 25.

The temperature increase gradient detection circuit 25 detects the temperature increase gradient a of the heater 1 based on the detection signal ST, and the gradient detection signal Sa is applied to the reference voltage generation circuit 26. Note that this temperature rise gradient detection circuit 25 can be constructed from, for example, a differentiating circuit.

The reference voltage generation circuit 26 generates a reference voltage signal Vr corresponding to the slope detection signal Sa based on the relationship shown in FIG. 10, and the reference voltage signal Vr is as follows.
It is added to the reference signal input terminal of comparator 3. Note that this reference voltage generation circuit 26 can be constructed by a function generator in which a function as shown in FIG. 10 is set.

The comparator 3 outputs a logic H level signal LO when the detection signal ST is smaller than the reference voltage signal Vr, and
When the detection signal ST is higher than the reference voltage signal Vr, a logic L level signal LO is outputted, and the output signal LO is applied to the solid stay mill relay 16.

The solid state relay 16 is turned on when the signal LO is at the logic 1 level, and turned off when the signal LO is at the logic L level.

A temperature protection circuit 27 connected in series between the power supply 8 and the heater 1 is configured to maintain the temperature of the heater 1 at a specified value (for example,
It is designed to turn off when the temperature exceeds the allowable limit temperature Tc) to protect circuit elements, and is made up of, for example, a temperature fuse.

With the above configuration, when increasing the temperature of the heater 1, the slope detection signal Sa is initially at a low value, so the reference voltage generation circuit 26 generates the reference voltage signal Vr of the voltage value v0 as described above. is generated and added to comparator 3.

As a result, the comparator 3 outputs a logic H level signal LO, the solid state relay 16 is turned on, and the power supply 8 is applied to the heater 1. As a result, the heater 1 is energized and its temperature is increased. Rise.

As the temperature of the heater 1 increases, the value of the detection signal ST increases, and the temperature increase gradient detection circuit 25 outputs a gradient detection signal Sa corresponding to the increase gradient.

When the value of the slope detection signal Sa is equal to or less than the slope value 80, the reference voltage generation circuit 26 fixes the value of the reference voltage signal Vr to the voltage value v0.

Then, when the value of the detection signal ST becomes larger than the value of the reference voltage signal Vr, the output signal LO of the comparator 3 falls to the logic L level, thereby turning off the solid state relay 16 and turning off the heater 1. Power is turned off.

The temperature rise of the heater 1 stops when the delay time td has elapsed from that point, and after that, the temperature of the heater 1 gradually decreases.

Then, the temperature of the heater 1 becomes lower than the reference temperature Tr,
When the detection signal ST becomes equal to or lower than the reference voltage signal Vr,
The output signal LO of the comparator 3 rises to the logic H level, thereby energizing the heater 1 again.

The temperature of heater 1 increases.

After this, the heater 1 is turned on and off based on the magnitude relationship between the reference voltage signal Vr and the detection signal ST, and as a result, the temperature of the heater 1 is controlled to be around the reference temperature Tr.

Further, the reference voltage generation circuit 26 sets the signal value of the reference voltage signal Vr based on the temperature increase gradient of the heater 1, and the temperature increase gradient of the heater 1 is the gradient value a.

, the signal value of the reference voltage signal Vr becomes smaller according to the gradient value, so even when the heater 1 is de-energized and the temperature of the heater l has finished overshooting, the temperature of the heater 1 is It is possible to prevent the temperature from exceeding the allowable limit temperature Tc.

Further, for example, as shown in FIG. 8, the heater 1 that heats the fixing roller 21 must raise the temperature of the fixing roller 21 to the target value Tr before the recording paper 23 arrives at the fixing roller 21. Must be.

Therefore, the temperature increase gradient A necessary for the heater 1 used in such a portion is set as shown in the following equation (■).

A > (Tb-Ta) / (ib-to) Yu(
■) However, at time t1. represents the time when the temperature of the heater l, which was turned on at time t0, rises to temperature Tb (see FIG. 9).

In this way, even when the temperature increase gradient A of the heater 1 is set, the reference voltage generation circuit 26 generates an appropriate reference voltage signal Vr based on the actual measured value of the temperature increase gradient.
The temperature of heater 1 overshoots and reaches the allowable limit temperature Tc.
It is possible to avoid situations where the

In the above-described embodiments, the present invention is applied to a heater that heats the fixing roller, but the present invention can be similarly applied to heaters used for other heating purposes.
be able to.・.

In the above-mentioned embodiment, the heater on/off switch 1,
An explanation of the timing is omitted.

[Effects of the Invention] As explained above, according to the present invention, the heater, ρ
Equipped with gradient detection means to detect temperature rise gradient.

At the start of heater drive, the heater is driven at a duty of 100%, and when the heater temperature reaches a specified value lower than the target value, the subsequent duty is set based on the detection result of the gradient detection means, and the heater temperature is - The 11 duty of energization is adjusted before the target value in response to the temperature increase gradient, so the overshoot amount of the heater temperature can be suppressed. In addition, since the duty is set to 100% at the start of driving, the power supply capacity can be fully utilized and the time required for the heater temperature to reach the target value can be significantly shortened. . Furthermore, since the reference signal for energization of the heater is formed in accordance with the temperature increase gradient of the heater, the effect of the overshoe 1 of the heater can be significantly suppressed.
・:i′,′・

[Brief explanation of the drawing]

Fig. 1 is a block diagram illustrating a heater temperature control device according to an embodiment of the present invention, Fig. 2 is a waveform diagram showing an example of the duty of the heater, a drunken pulse signal, and Fig. 3 is an example of heater temperature control. 4 is a block diagram showing a concrete example of the device shown in FIG. 1, and FIG. 5 is a graph showing temperature control. No.1. A flowchart showing an example of processing 1, which realizes ,function, ,..., ,The sixth part is where the function of the Neity transformer circuit is realized! FIG. 7 is a flowchart showing an example of realizing Du, - Te:, I, Tie, and FIG. 8 is another embodiment of the present invention.
The structure of the fixing roller, which has a fixed force, will be explained. FIG. 9 is a schematic diagram of the structure of the fixing roller. Figure 45110 of graph 45110 illustrates the relationship between severe upward slope and standard, fl, and group.
? Figure 1, 3. FIG. 11 is a block diagram showing another embodiment of the present invention: a heating, temperature, temperature control device; , , ・・Ding：・、：１
・1...Heater, 2...Temperature, test bar 1.3...
・Hiwani device, 4=・Temperature control section, 5...And-route,
9...De,,Uni,:,T modulation circuit, 7...Heater mate path, 8...Power supply. 11...Thermistor, 12.14...Resistor, 13.
・Wow, did you finish the tip? rocomputer, 14-...
・・Anna, 10g/de, ・Internal converter, 15・・Microcomputer, 16・Warm 11.・：、Nlid state relay, 17... operational amplifier, 19.20...
・Voltage dividing resistor, 25...Temperature rise gradient detection circuit. 26... Reference voltage generation circuit, 27... Temperature protection circuit.

Claims (2)

[Claims] (1) In a heater temperature control device that detects the heater temperature and controls the driving duty of energization of the heater so that the detected temperature becomes a target value, the heater temperature control device includes a gradient detection means that detects the temperature rise gradient of the heater, and a heater drive start. The heater is characterized by comprising a control means that sometimes drives the heater at a duty of 100%, and when the heater temperature reaches a specified value lower than the target value, sets the subsequent duty based on the detection result of the gradient detection means. Heater temperature control device. (2) In a heater temperature control device that controls the heater temperature to a target value, a gradient detection means detects the temperature rise gradient of the heater, and a reference temperature signal of the heater is generated based on the temperature rise gradient detected by the gradient detection means. What is claimed is: 1. A heater temperature control device comprising: a reference signal generating means for generating a heater temperature; and an energization control means for controlling energization of the heater based on the reference temperature signal and a heater temperature detection signal.