JP3259449B2 - Heater control device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a heater control device for heating an object to be heated.

[0002]

2. Description of the Related Art For example, when molding a door trim of an automobile, a plastic sheet having a relatively large area is used as a material and is heated by a heating furnace at the time of molding. A far-infrared heater is usually used as a heater of this type of heating furnace. In this case, as the far-infrared heater, a ceramic heater in which the heating wire and the temperature detecting end of the temperature detector are embedded in ceramic is used, which has a high heating speed and a temperature distribution for surface heating. It has an advantage that it is good, can uniformly heat a wide area, and has excellent corrosion resistance. In general, it is composed of a combination of several tens to several hundreds (500 in many cases) unit heaters.

FIGS. 8 to 10 show a first conventional example. That is, as shown in FIG.
For example, it is constituted by 56 unit heaters 2,
Each unit heater 2 is supplied with power by a power supply line 2a. A thermocouple 3 as a temperature detector is provided only in the center unit heater 2 of the 56 unit heaters 2 of the far infrared heater 1.

As shown in FIG. 9, each unit heater 2 is provided with a power regulator 4 and a fuse 5 corresponding thereto, and an NFB (no-fuse breaker) 6 and an SSR common to the unit heaters 2. (Solid state relay) 7
(See FIG. 10). Each of the unit heaters 2 has an AC200 through a series circuit of the NFB 6 and the contact portion 7a in common, and a corresponding series circuit of the power regulator 4, the fuse 5, and the power supply line 2a.
It is connected between AC power supply lines 8 and 9 to which V is applied.
In this case, the power regulator 4 has a volume 4a, and each unit heater 2 is set by the setting of the volume 4a.
Are adjusted by phase control.

[0005] As shown in FIG.
It is connected between AC power supply lines 11 and 12 to which C100V is applied. The temperature controller 10 is connected to the thermocouple 3, and cuts off the power to the drive unit 7b of the SSR 7 with 24 VDC so that the temperature measured by the thermocouple 3 becomes the temperature target value. Is turned on and off.

FIGS. 11 to 13 show a second conventional example. That is, as shown in FIG. 11, the unit heater 2 of the far-infrared heater 1 is divided into 11 block heaters 13 each including a plurality of blocks as one block.
Power is supplied from the power supply line 13a every three. And thermocouple 3
Are provided for each block heater 13.

[0007] As shown in FIGS.
The fuse 5 is provided for each block heater 13, and the temperature controller 10 is also provided for each thermocouple 3. As shown in FIG. 12, each block heater 13 is connected between the AC power supply lines 8 and 9 via the NFB 6 in common and a series circuit of the contact portion 7a of each SSR 7, the fuse 5 and the power supply line 13a. ing. Further, FIG.
As shown in FIG. 1, each temperature controller 10 is connected to an AC power supply line 11,1.
2 and each S is controlled by PI (proportional / integral) control.
The contact portion 7a of the SR 7 is turned on and off.

[0008]

In the first conventional example shown in FIGS. 8 to 10, the relative temperature distribution is set by a power regulator 4 provided for each unit heater 2, and one thermocouple 3 is used. Since the temperature is controlled by measuring the representative temperature,
Numerous power regulators 4 provided one-to-one with unit heaters 2
The adjustment of the power regulator 4 must be performed each time the model is changed, and it takes a long time to change the setup. The quality is not stable because of the operator's feeling.

In the second conventional example shown in FIGS. 11 to 13, since the temperature control is performed by PI control for each block heater 13, the problem as in the first conventional example can be solved. However, in the heating furnace, production items are frequently changed due to recent small-lot production orientation, and it is necessary to frequently change the heater surface temperature distribution for each production item. Since the step-shaped discontinuity is different for each production item, the number of times of the temperature control in the non-steady state until reaching the steady state near the target temperature value increases.

FIG. 14 shows experimental results when the target temperature is changed from 200 ° C. and 250 ° C. to 300 ° C. in the second conventional example. As is clear from FIG. 14, even in the PI control, the amount of overshoot is large in the temperature control in an unsteady state, and the time until the temperature converges to the target temperature value is long.

Further, in the far infrared heater, it is known that the peak wavelength of the far infrared ray varies depending on the heater surface temperature, and the output operation amount (the ratio of the heater energizing time within a certain time (%) to the figure) The change in the stable temperature with respect to (5) is also non-linear, and the characteristics also vary greatly depending on the type of heater. Accordingly, the temperature control in the steady state also has a problem that the control accuracy is insufficient with the conventionally used PI control.

The present invention has been made in view of the above circumstances, and a first object of the present invention is to provide control in an unsteady state.
An object of the present invention is to provide a heater control device capable of minimizing an overshoot amount and converging to a target temperature value early.

A second object of the present invention is to provide a heater control device capable of performing high-precision control in steady-state control.

[0014]

According to a first aspect of the present invention, there is provided a heater control device, comprising: a heater energizing means for energizing a heater; and a temperature measuring means for measuring a current time temperature of the heater. Measuring means, temperature storing means for storing the temperature of the heater a predetermined time before, and temperature rise calculating a temperature rise rate from the current temperature by the temperature measuring means and the temperature before the predetermined time by the temperature storing means. Rate calculation means, a temperature target value storage means for storing a set temperature target value, and a determination means for determining whether the heater is in an unsteady state or a steady state based on the current temperature by the temperature measurement means,
When the determining means determines that the temperature is in an unsteady state, an estimation after a predetermined time based on the temperature at the current time by the temperature measuring means, the temperature rise rate by the temperature rise rate calculating means, and the target temperature value by the target temperature storage means. Estimated temperature deviation calculating means for calculating the temperature deviation; output correction value cross table storage means for storing an output correction value using the temperature rise rate and the temperature deviation as parameters; and the temperature rise rate and the estimation by the temperature rise rate calculation means. Output correction value determination means for reading an output correction value from the output correction value cross table based on the estimated temperature deviation by the temperature deviation calculation means; output value storage means for storing a previous output value; Current output value calculating means for calculating a current output value in an unsteady state from a previous output value by the means and an output correction value by the output correction value determining means; The current output value by calculating means has a feature in the configuration comprising and an output means for controlling said heater energizing means.

According to a second aspect of the present invention, there is provided a heater control device, comprising: a heater energizing means for energizing a heater; a temperature measuring means for measuring a current time temperature of the heater; Temperature storage means for storing the temperature before a predetermined time, temperature rise rate calculation means for calculating a temperature rise rate from the current time temperature by the temperature measurement means and the temperature before the predetermined time by the temperature storage means, and setting. Temperature target value storage means for storing the obtained temperature target value; determining means for determining whether the heater is in an unsteady state or a steady state based on the current temperature by the temperature measuring means; and determining that the heater is in a steady state. A temperature deviation calculating means for calculating a temperature deviation at the current time from the current temperature by the temperature measuring means and the temperature target value by the temperature target value storing means; Output value table storage means for storing a constant output value from the output value table storage means based on the temperature target value stored by the temperature target value storage means; and a temperature rise rate and temperature. Offset correction value cross table storage means for storing the offset correction value using the deviation as a parameter, and the offset correction based on the temperature rise rate by the temperature rise rate calculation means and the temperature deviation at the current time by the temperature deviation calculation means. Offset correction value determining means for reading an offset correction value from a value cross table storage means, offset value storing means for storing a previous offset value, and a previous offset value by the offset value storing means and the steady output value determining means. From the steady output value and the offset correction value by the offset value correction means. And the current output value calculating means for calculating an output value, having characterized by being provided with an output means for controlling said heater energizing means by the current output value by the current output value calculation means.

[0016]

According to the heater control device of the first aspect, the temperature rise rate is calculated from the temperature before the predetermined time and the temperature at the current time, and the temperature rise rate after the predetermined time is calculated from the temperature rise rate and the temperature at the current time. A temperature estimation value is calculated, an estimated temperature deviation is calculated from the temperature estimation value and the temperature target value, and an output correction value is calculated from a preset output correction value cross table based on the temperature rise rate and the estimated temperature deviation. Then, the current output value is calculated from the output correction value and the previous output value, and the heater energizing means is controlled based on the current output value in the unsteady state.

Therefore, by repeating the above operation, the temperature deviation gradually decreases as the measured temperature approaches the temperature target value, and the heater temperature converges to the temperature target value.

According to the heater control device of the second aspect, the temperature deviation at the current time is calculated from the temperature at the current time and the temperature target value, and the temperature deviation is set in advance based on the temperature deviation and the temperature rise rate. The offset correction value is read from the offset correction value cross table, the current offset value is calculated from the offset correction value and the previous offset correction value, and the steady output value at the temperature target value is further read from the output value table. The current output value is calculated from the steady output value and the current offset value, and the heater energizing means is controlled based on the steady state current output value.

Therefore, by repeating the above operation, the offset value gradually decreases as the measured temperature approaches the temperature target value, and the temperature of the heater matches or approximates the temperature target value.

[0020]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below with reference to FIGS. The far-infrared heater 20, which is a heater of the heating furnace, is made of a ceramic heater as in the prior art, and as shown in FIG.
It is constituted by. The 64 unit heaters 21
The plurality of unit heaters 21 are divided into 13 block heaters 22 as one block, and power is supplied to each block heater 22 by a power supply line 22a. In this case, each of the block heaters 22 includes two large block heaters including eight unit heaters 21 positioned at both left and right ends, and two large block heaters including six unit heaters 21 positioned at front and rear ends. It comprises a middle block heater and nine small block heaters composed of four unit heaters 21 surrounded by these. Each of the thirteen block heaters 22 is provided with a thermocouple 23 as a temperature detecting means.

FIG. 3 shows a control device of the far-infrared heater 20, and a circuit section 24 enclosed by a broken line is provided for each block heater 22. That is, AC2
Between the AC power supply lines 25 and 26 to which 00V is applied, a series circuit of the block heater 22 and the SSR 27 (contact portion thereof) serving as heater energizing means is connected, and a surge absorbing element 28 is connected in parallel with the SSR 27. A snubber circuit 29 is connected in parallel.

The thermocouple 2 provided on the block heater 22
3 is connected to the input terminal of the amplifier 30, and (the drive unit of) the SSR 27 is connected to the output terminal of the drive circuit 31 as an output means. The output terminal of the amplifier 30 is connected to a corresponding input port of the microprocessor 32, and the input terminal of the drive circuit 31 is connected to a corresponding output port of the microprocessor 32.

The other input and output ports of the microprocessor 32 are connected to the output and input terminals of the twelve circuit sections 24 corresponding to the remaining twelve block heaters 22.
The control device 33 is configured. FIG. 1 is a block diagram showing the control contents of the microprocessor 32 by function.
The details will be described later.

Next, the operation of the present embodiment will be described with reference to FIGS. 1 and 4 to 7. The thermocouple 23 generates a thermal power signal corresponding to the temperature of the block heater 22, and the amplifier 30 raises the voltage level of the signal and linearizes the signal to supply the signal to the input port of the microprocessor 32. The drive circuit 31 is provided with a current output value, that is, an output manipulated variable from the microprocessor 32. This output manipulated variable is on-off 1
The drive circuit 31 indicates the ratio (%) of the ON time to the cycle (for example, 1 sec).
The contact portion 27 is turned on and off so that the block heater 22 is turned on and off.

When the operation of the control device 33 is started (started), the microprocessor 32 performs a control operation as follows. That is, in step S1, the thermocouple 23
Then, the current temperature of the block heater 22 is measured (read) via the amplifier 30. In step S2, the measured temperature at the current time is sequentially stored in the temperature storage means 33A (see FIG. 1) at the current time, and stored in the temperature storage means 33B (see FIG. 1) a predetermined time earlier. Step S
In step 3, the temperature before the predetermined time is read from the temperature storage means 33A, and in step S4, the temperature rise rate is calculated from the read temperature before the predetermined time and the temperature at the current time.

In step S5, it is determined whether the temperature at the current time is within the set range between the upper limit and the lower limit centered on the temperature target value stored in advance in the temperature target value storage means 33C (see FIG. 1). In the case of "NO", it is determined that it is in an unsteady state. Hereinafter, the control operation of the microprocessor 32 in the unsteady state will be described.

If "NO" is determined in the step S5, the process proceeds to a step S6, where an estimated temperature value after a predetermined time is calculated from the temperature at the current time and the temperature rise rate. In the next step S7, an estimated temperature deviation after a predetermined time is calculated from the estimated temperature value and the target temperature value. In step S8, an output correction value is read from the cross table storage means 33D (see FIG. 1) of the temperature rise rate and the estimated temperature deviation based on the temperature rise rate and the estimated temperature deviation after a predetermined time.

That is, the cross table storage means 33D (for output correction value) stores an optimum output correction value using the temperature rise rate and the temperature deviation as parameters, and the output correction value is fuzzy. It was determined by inference. Therefore, in step S8, the cross table storage unit 3 is operated based on the temperature rise rate and the estimated temperature deviation.
The optimum output correction value at the current time is read from 3D.

In step S9, the previous output value is read from the previous output value storage means 33E (see FIG. 1). In step S10, the output correction value is added to the previous output value to obtain the current output value. In step S11, the current output value is stored in the output value storage means 33E as the previous output value, and in step S12, the current output value is output and given to the drive circuit 31, and in step S1
Will come back to.

At the start of the operation of the control device 33, the initial temperature is set in the temperature storage means 33B as the temperature before a predetermined time, and the initial output value is set in the output value storage means 33E as the previous output value. As a result, the microprocessor 32 outputs the output manipulated variable which is the current output value of 100% in step S12, and the drive circuit 31 turns on and off the contact portion of the SSR 27 in step S12.
The block heater 22 is turned on for a period, and the block heater 22 is fully energized.

Therefore, when the microprocessor 32 repeats the operations of steps S1 to S12 as described above, the current output value is controlled so that% gradually decreases so as to become an output value that provides the target temperature value. .

When the temperature of the block heater 22 reaches the set range by the microprocessor 32 performing the above-described unsteady state control, the microprocessor 32 determines "YES" in step S5. It is determined that this is a steady state. Hereinafter, the operation of the microprocessor 32 in this steady state will be described.

If "YES" is determined in the step S5, the process shifts to a step S13, where the temperature at the current time is read out several times from the temperature storage means 33A at the current time, and the same value is obtained for several consecutive times. Is determined. If it is determined as "YES" in step S13, the process proceeds to step S14, where a temperature deviation at the current time is calculated from the temperature at the current time and the temperature target value. In step S15, the offset correction value is read from the cross table storage means 33F (see FIG. 1) of the temperature rise rate and the current time temperature deviation based on the temperature rise rate and the current time temperature deviation.

That is, the (offset correction value) cross table storage means 33F stores the optimum offset correction value using the temperature rise rate and the temperature deviation as parameters, and the offset correction value is fuzzy. It was determined by inference. Therefore, step S1
In 5, the optimum offset correction value at the current time is read from the cross table storage means 33F based on the temperature rise rate and the temperature deviation at the current time.

In step S16, the previous offset value is read from the previous offset value storage means 33G (see FIG. 1), and in step S17, the above-described offset correction value is added to the previous offset value to obtain the current offset value. In step S18, the steady output value at the target temperature value is read from the output value table storage means 33H (see FIG. 1) for the steady temperature.

That is, as shown in FIG. 5, the table storage means (for output value) 33H stores the relationship between the heater temperature in the steady state (steady temperature) and the output manipulated variable (output value). The output manipulated variable (output value) is indicated by the ratio (%) of the ON time in one ON / OFF cycle (for example, 1 sec).
Note that the table storage unit 33H actually stores the output operation amount such that the minimum on-time is, for example, 5 ms and increases stepwise in units of 5 ms. Therefore, in this step S18, a steady output value (output manipulated variable) for achieving the temperature target value is read.

In step S19, the above-mentioned current offset value is added to the steady output value to obtain a current output value. In step S20, the current offset value is stored in the storage means 33G as the previous offset value. S
At 12, the current output value is output to the drive circuit 31.

As described above, when the current output value is corrected by the offset correction value, the duty ratio of the block heater 22 changes, so that the temperature of the block heater 22 also changes. The microprocessor 32 determines "NO" at the time of step S13, and proceeds to step S21. This step S21
In, the offset value is not corrected in steps S14 to S17, and the process proceeds to step 18 with the previous offset value as the current offset value. That is, when the temperature at the current time changes in the steady state, the output value is not changed until the temperature stabilizes.

By repeating the above operation, the offset value is gradually reduced, and the temperature of the block heater 22 is controlled so as to match or approximate the temperature target value.

By the way, the microprocessor 32 performs control by software as shown in FIG. 4. When this is shown in a block diagram for each function, FIG.
It becomes as shown in.

That is, the microprocessor 32 includes a current time temperature measuring means 32A (corresponding to steps S1 to S3), a temperature rise rate calculating means 32B (corresponding to step S4), and a steady state / unsteady state determining means 32C (corresponding to step S4). (Corresponding to step S5), estimated temperature deviation calculating means 32D (corresponding to steps S6 and S7), output correction value determining means 32E.
(Steps S6 to S8), current output value calculating means in an unsteady state (corresponding to steps S9 to S12), and determining means 32G for determining whether the temperature at the current time is the same value several times continuously (step S13).
), Temperature deviation calculating means 32H at the current time (corresponding to step S14), offset correction value determining means 32I (corresponding to steps S15 to S17), steady output value determining means 32J (corresponding to step S18), and steady state. Current output value calculating means 32K (steps S18 to S20 and S
12).

The control operation of one block heater 22 has been described above. The circuit section 24 is provided for each of the thirteen block heaters 22, and the microprocessor 32 has The control of the thirteen circuit sections 24 is controlled in series.
In this case, the temperature target values set and stored in the temperature target value storage means 33C belonging to each block heater 22 are set to different values based on the relative temperature distribution. The correction value cross table storage unit 33F and the output value table storage unit 33E can be commonly used.

According to this embodiment, the following effects can be obtained. That is, in the unsteady state of the block heater 22, the microprocessor 32 calculates the temperature rise rate from the temperature before the predetermined time and the temperature at the current time, and calculates the temperature rise rate after the predetermined time from the temperature rise rate and the temperature at the current time. , An estimated temperature deviation is calculated from the estimated temperature value and the target temperature value, an output correction value is read based on the temperature rise rate and the estimated temperature deviation, and the output correction value The current output value is obtained by adding the previous output value, and the SSR 27 is turned on / off via the drive circuit 31 with the current output value in the unsteady state, so that the duty ratio of the block heater 22 is controlled. did.

Accordingly, the output value to the SSR 27 for controlling the duty ratio of the block heater 22 is
The temperature of the block heater 22 is controlled such that the temperature of the block heater 22 gradually converges to the temperature target value as the temperature of the second heater approaches the temperature target value.

FIG. 6 shows the temperature characteristics of an experiment in which control was performed from the initial temperature (normal temperature) to the target temperature values of 318 ° C. and 353 ° C. As is clear from FIG.
Compared with the case of the PI control shown in FIG. 14 of the conventional example, the overshoot amount is about 15 ° C. in the related art, whereas the overshoot amount is 2 to 3 ° C. in the present embodiment. In contrast, in the related art, it takes 5 minutes or more to converge from the unsteady state to the steady state, whereas in the present embodiment, the time is reduced to 4 minutes or less.

Further, in the steady state of the block heater 22, the microprocessor 32 calculates a temperature deviation at the current time from the temperature at the current time and the temperature target value, and performs an offset based on the temperature deviation and the temperature rise rate. Read the correction value, add this offset correction value to the previous offset value to obtain the current offset value, read the steady output value corresponding to the temperature target value, and add the current offset value to this steady output value Thus, the current output value is obtained, and the current output value in the steady state is given to the drive circuit 31.

Accordingly, as the temperature of the block heater 22 becomes closer to the target temperature, the offset value gradually decreases, so that the temperature of the block heater 22 is highly accurate so as to match or approximate the target temperature. Can be controlled.

In the second conventional example, since the multi-point control of the eleven block heaters 13 is employed, not only are the temperature target values set differently to improve the relative temperature distribution, but also each PI It was necessary to adjust the control circuit constants. However, in this embodiment, even if it is necessary to make the temperature target values of the thirteen block heaters 22 different, the cross table storage means 33D and 33F corresponding to the conventional PI control circuit constants are set by fuzzy inference. Since they can be used in common after they have been adjusted, there is no need to adjust them as in the case of conventional circuit constants.

In particular, in the second conventional example, it is necessary to adjust and change the circuit constant every time the temperature target value is changed by the type change. In the present embodiment, however, the cross table storage set by fuzzy inference is required. Since the means 33D and 33F are used, there is no need for change and adjustment, and the mold changing operation can be performed easily and in a short time.

In the above embodiment, if a plurality of control devices 33 are provided, it is possible to control a far-infrared heater comprising several hundred unit heaters.

Although the above embodiment is applied to a heating furnace, it is needless to say that other embodiments can be applied.
Therefore, the heater is not limited to the far-infrared heater including a large number of unit heaters, but may be a single heater.

In addition, the present invention is not limited to the embodiment described above and shown in the drawings, and it is a matter of course that the present invention can be carried out by appropriately modifying it without departing from the gist thereof.

[0053]

As described above, the present invention has the following effects.

According to the heater control device of the first aspect, in the unsteady state of the heater, the rate of temperature rise of the heater and the estimated temperature deviation after a predetermined time from the temperature target value are calculated, and the output is calculated from these. Since the correction value is determined, the current output value is obtained from the output correction value and the previous output value, and the heater cutoff control is performed based on the current output value.
The amount of overshoot can be reduced as much as possible, and the temperature of the heater can be quickly converged to the target temperature value.

According to the heater control device of the second aspect, in the steady state of the heater, the temperature rise rate of the heater and the temperature deviation at the current time from the temperature target value are calculated, and the offset correction value is determined from these. Then, the current offset value is obtained from the offset correction value and the previous offset value,
Further, the current output value is obtained from the current offset value and the steady-state output value corresponding to the temperature target value, and the heater power is controlled based on the current output value. Control can be performed with high precision to match or approximate the value.

[Brief description of the drawings]

FIG. 1 is a block diagram of an electrical configuration showing an embodiment of the present invention.

FIG. 2 is a perspective view of a far-infrared heater.

FIG. 3 is an electrical configuration diagram

FIG. 4 is a flowchart showing control contents.

FIG. 5 is a graph showing output manipulated variable-heater temperature characteristics.

FIG. 6 is a temperature characteristic diagram of a heater.

FIG. 7 is a temperature deviation characteristic diagram of a heater.

FIG. 8 is a diagram corresponding to FIG. 2 showing a first conventional example.

FIG. 9 is an electrical configuration diagram

FIG. 10 is a wiring diagram of a temperature controller.

FIG. 11 is a view showing a second conventional example and corresponding to FIG. 8;

FIG. 12 is a diagram corresponding to FIG. 9;

FIG. 13 is a diagram corresponding to FIG. 10;

FIG. 14 is a temperature characteristic diagram of a heater.

[Explanation of symbols]

In the drawing, 20 is a far infrared heater (heater), 21 is a unit heater, 22 is a block heater, 23 is a thermocouple (temperature detecting means), 24 is a circuit section, 27 is an SSR (heater energizing means), 30 is an amplifier, 31 is a drive circuit (output means), 3
2 is a microprocessor, 32A is a current time temperature measuring means, 32B is a temperature rise rate calculating means, 32C is a steady state / unsteady state determining means, 32D is an estimated temperature deviation calculating means, 32E is an output value determining means, and 32F is an output value determining means. Non-steady state current output value determination means, 32G is determination means, 32H is current time temperature deviation calculation means, 32I is offset correction value determination means, 32J is steady state output value determination means, 32K is steady state current output value Calculating means, 33 is a control device, 33A is a current time temperature storing means, 33B is a temperature storing means a predetermined time ago,
33C is a temperature target value storage means, 33D is a cross table storage means for the temperature rise rate and the estimated temperature deviation, 33E is a storage means for the previous output value, 33F is a cross table storage means for the temperature rise rate and the current time temperature deviation, 33G indicates a previous offset value storage means, and 33H indicates a table storage means for output values with respect to a steady temperature.

Claims (2)

(57) [Claims] 1. A heater energizing means for energizing a heater, a temperature measuring means for measuring a temperature of the heater at a current time, a temperature storing means for storing a temperature of the heater before a predetermined time, and these temperature measuring means Temperature rise rate calculation means for calculating a temperature rise rate from the current time temperature by the temperature storage means and the temperature before a predetermined time by the temperature storage means; a temperature target value storage means for storing a set temperature target value; and the temperature measurement means. Determining means for determining whether the heater is in an unsteady state or a steady state based on the temperature at the current time, and calculating the current time temperature and temperature increase rate by the temperature measuring means when the determining means determines that the heater is in an unsteady state. Means for calculating an estimated temperature deviation after a predetermined time based on the temperature rise rate by the means and the temperature target value by the temperature target value storage means; and a temperature rise rate and an estimated temperature deviation. An output correction value cross table storage means for storing an output correction value as a parameter, and the output correction value cross table based on the temperature rise rate by the temperature rise rate calculation means and the estimated temperature deviation by the estimated temperature deviation calculation means. Output correction value determining means for reading an output correction value from a table storage means; output value storing means for storing a previous output value; and a previous output value by the output value storing means and an output correction by the output correction value determining means. A heater control device comprising: a current output value calculating means for calculating a current output value in an unsteady state from the current value; and an output means for controlling the heater energizing means based on a current output value by the current output value calculating means. . 2. A heater energizing unit for energizing a heater, a temperature measuring unit for measuring a temperature of the heater at a current time, a temperature storing unit for storing a temperature of the heater before a predetermined time, and these temperature measuring units. Temperature rise rate calculation means for calculating a temperature rise rate from the current time temperature by the temperature storage means and the temperature before a predetermined time by the temperature storage means; a temperature target value storage means for storing a set temperature target value; and the temperature measurement means. Determination means for determining whether the heater is in an unsteady state or a steady state based on the current time temperature, and when the determination means determines that the heater is in a steady state, storing the current time temperature and the temperature target value storage by the temperature measurement means. Temperature deviation calculating means for calculating a temperature deviation at the current time from the temperature target value by the means; an output value table storage means for storing an output value for a steady temperature; Means for reading a steady output value from the table storage means for output value based on a target temperature value by means, and a cross table for offset correction value for storing an offset correction value using a temperature rise rate and a temperature deviation as parameters. Storage means; offset correction value determination for reading an offset correction value from the offset correction value cross table storage means based on the temperature rise rate by the temperature rise rate calculation means and the temperature deviation at the current time by the temperature deviation calculation means; Means, an offset value storage means for storing a previous offset value, and a previous offset value by the offset value storage means,
Current output value calculating means for calculating a steady state current output value from the steady output value determined by the steady output value determining means and the offset correction value calculated by the offset value correcting means; and A heater control device, comprising: an output unit that controls an energizing unit.