JP2000228269A - HEATER CONTROLLER, ELECTROPHOTOGRAPHIC RECORDING DEVICE, HEATER CONTROL METHOD, AND METHOD OF CONTROLLING HEAT FIXING HEATER IN ELECTROPHOTOGRAPHIC RECORDING DEVICE - Google Patents

Abstract

(57) [Problem] To provide a heater control device capable of promptly shutting off energization of a heater without reaching an abnormally high temperature even when abnormal energization of the heater occurs. SOLUTION: Based on temperature information from a thermistor 71b, a wave number of an alternating current supplied to the heater 71 is controlled to control the heater 71 to a predetermined temperature. At this time, the number of waves of the alternating current supplied to the heater 71 by the circuit 18 is counted for each half wave via the heater current pulse generation circuit 17, and when the count value becomes equal to or larger than a predetermined value,
The heater current cutoff circuit 15 cuts off the current supply to the heater 71 and maintains the cutoff state. And the circuit 19
The time during which the AC current supplied to the heater 71 does not flow is counted, and when the counted value exceeds a predetermined value, the count value of the circuit 18 is cleared.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a heater control apparatus and a heater control method used in a heat fixing process of an electrophotographic recording apparatus, an electrophotographic recording apparatus equipped with the heater control apparatus, and a heat control apparatus for the electrophotographic recording apparatus. The present invention relates to a method for controlling a fixing heater.

[0002]

2. Description of the Related Art In general, an electrophotographic recording apparatus for performing recording on recording paper in an electrophotographic recording system has a primary charger, an exposure light source, a developing device, and the like arranged around a photosensitive drum. Exposure is performed to form a toner image on the exposed portion. Then, the toner image is transferred onto the recording paper by the transfer charger, and the heat fixing device fixes the toner image transferred onto the recording paper, thereby completing the recording.

In recent years, a film heating type heat fixing device has been widely used as a heat fixing device of such an electrophotographic recording apparatus from the viewpoint of quick start and power saving. The film heating method is as follows. As shown in the cross-sectional view of FIG. 8, between a ceramic heater 71 as a heating element and a pressing roller 72 as a pressing member,
A fixing nip N is formed by sandwiching a heat-resistant film 73 of polyimide or the like. Then, the recording paper S on which the unfixed toner image T is formed and carried is introduced between the heat-resistant film 73 and the pressure roller 72 in the fixing nip N, and the fixing nip N is formed together with the heat-resistant film 73. By nipping and conveying, the heat of the ceramic heater 71 is given to the recording paper S via the heat-resistant film 73 and heated, and the toner image is transferred to the recording paper S.
Is fixed by heat.

[0004] In the drawing, reference numeral 74 denotes a stay, which holds the ceramic heater 71 and the heat-resistant film 73. The ceramic heater 71 includes a resistor 71a and a thermistor 71b. The resistor 71a generates heat by supplying an AC current, and the thermistor 71b monitors the temperature of the ceramic heater 71.

FIG. 9 is a circuit diagram showing a heater control device of the film heating type fixing device shown in FIG.

In FIG. 1, reference numeral 81 denotes a microprocessor (hereinafter, MPU), which includes a ROM, a RAM, a timer, and the like. The MPU 81 has an output port PA0 and an analog input port AN0 having an A / D function of converting an analog voltage into a digital value and detecting the digital value.

Further, reference numeral 71 denotes the ceramic heater shown in FIG. The thermistor 71b in the ceramic heater 71 has one terminal connected to the ground and the other terminal connected to the pull-up resistor 82 and the analog input port AN0 of the MPU 81.
Indicates the temperature of the ceramic heater 71.

Reference numeral 83 denotes a heater driver, which includes a triac 83a, a phototriac coupler 83b having a built-in zero-cross function, a transistor 83c, and a resistor 83.
d, 83e and 83f. The first terminal of the triac 83a is connected to the commercial AC power supply 84, the second terminal is connected to the resistor 71a in the ceramic heater 71, and the base of the transistor 83c is connected to the MPU 81.
Port PA0.

When the MPU 81 sets the port PA0 to "H" level, the transistor 83c turns on. as a result,
The LED inside the phototriac coupler 83b is driven, and the triac inside the phototriac coupler 83b is turned on. As a result, as a result of turning on the triac 83a, the AC voltage is directly applied to the resistor 71a for heating unless the relay 85a described later is in the cut-off state.

On the other hand, the MPU 81 sets the port PA0 to "L".
When the level is set, the transistor 83c is turned off. As a result, since the LED inside the phototriac coupler 83c is not driven, the triac inside the phototriac is turned off. As a result, the triac 83a is turned off, so that the application of the AC voltage to the resistor 71a is cut off.

Further, the MPU 81 applies A to the resistor 71a.
The application / cutoff of the C voltage is performed based on the temperature information of the thermistor 71b, whereby the ceramic heater 71 is controlled to a predetermined temperature.

Reference numeral 85 denotes a heater current cutoff circuit. The heater current cutoff circuit 85 includes a relay 8 for cutting off AC current.
5a, transistor 85b, surge absorbing diode 8
5c, a diode driving circuit composed of a diode 85d and a pull-up resistor 85e, transistors 85f and 85g,
A diode 85h and resistors 85i, 85j, 85k,
85l of a latch circuit. Here, the relay driving circuit is a circuit for driving a relay 85a, and the latch circuit is a circuit for driving the relay 85a when power is turned on.
This is a circuit for connecting a, disconnecting the relay 86a when an error occurs, and maintaining its state.

When power is supplied to the heater current cutoff circuit 85, the transistors 85f and 85g are both in the off state, so that the transistor 85b is in the on state and the relay 85a is in the connected state. Further, when Verr, which is an output of the abnormal temperature detection circuit 86 described later, goes to the “L” level, the transistor 85f is turned on, and the transistor 85g is turned on, so that the transistor 85b is turned off and the relay 85a is turned off. Note that once the transistors 85f and 85g are turned on, the off state of the transistor 85b is maintained regardless of the state of Verr, so that the cutoff state of the relay 85a is maintained.

Reference numeral 86 denotes an abnormal temperature detecting circuit,
The comparator 86a compares the voltage Vref indicating the abnormal temperature defined by b and 86c with the thermistor voltage Vthm, and when Vthm <Vref, that is, when an abnormally high temperature is detected,
Verr = “L” is output to the current cutoff circuit 85.
In this way, the runaway of the MPC 81 and the triac 83
This prevents abnormal heating of the ceramic heater 71 due to a short-circuit failure of a.

[0015]

However, in the above conventional example, the runaway of the MPU 81 and the short-circuit of the triac 83a are detected by detecting the temperature, so that the ceramic heater 71 is in an abnormally high temperature state for a certain period. Once
If an abnormality occurs in the fixing device, the members of the fixing device may be damaged, which may lead to an increase in repair costs.

SUMMARY OF THE INVENTION In view of the above-mentioned conventional problems, the present invention provides a heater control apparatus and an electrophotographic recording apparatus capable of rapidly shutting off power supply to a heater without reaching an abnormally high temperature even when abnormal power supply to the heater occurs. It is an object of the present invention to provide an apparatus, a heater control method, and a control method of a heat fixing heater of an electrophotographic recording apparatus.

[0017]

According to a first aspect of the present invention, there is provided a heater control device, comprising: a heater temperature detector for detecting a temperature of a heater; and temperature information of the heater temperature detector. Heater temperature control means for controlling the heater to a predetermined temperature by controlling the wave number of the AC current supplied to the heater, and a wave number for counting the wave number of the AC current supplied to the heater every half wave Counting means; and heater current interrupting means for interrupting the current supply to the heater and maintaining the interrupted state when the count value of the wave number counting means becomes equal to or greater than a predetermined value. .

According to a second aspect of the present invention, in the heater control apparatus according to the first aspect, a time during which no AC current is supplied to the heater is measured, and the measured time becomes equal to or greater than a predetermined value. A time counting means for clearing the count value of the wave number counting means when the time has elapsed.

According to a third aspect of the present invention, in the heater control apparatus according to the first aspect, a voltage cycle of an AC power supply for supplying an alternating current to the heater is monitored, and the voltage cycle is monitored for a predetermined cycle. It is characterized by having a cycle detecting means for clearing the count value of the wave number counting means when no current flows through the heater.

In the electrophotographic recording apparatus according to the present invention, a toner image forming means for exposing a photosensitive member to form a toner image on the exposed portion, and transferring the toner image onto a recording medium. Transfer means, a heater having a heater, heat fixing means for thermally fixing the toner image transferred onto the recording medium by heat generated from the heater, and a heater control device for controlling the temperature of the heater. In the electrophotographic recording apparatus, the heater control device controls a wave number of an alternating current supplied to the heater based on temperature information of the heater temperature detecting means for detecting the temperature of the heater and the heater temperature detecting means. Heater temperature control means for controlling the heater to a predetermined temperature; wave number counting means for counting the number of waves of the alternating current supplied to the heater for each half-wave; When the count value of the cement means exceeds a predetermined value, to interrupt the current supply to the heater, characterized in that a heater current interrupting means for retaining the cut-off state.

According to a fifth aspect of the present invention, in the electrophotographic recording apparatus according to the fourth aspect, a time during which no AC current supplied to the heater flows is measured,
When the time value becomes equal to or more than a predetermined value, the time count means for clearing the count value of the wave number counting means is provided.

According to a sixth aspect of the present invention, in the electrophotographic recording apparatus of the fourth aspect, a voltage cycle of an AC power supply for supplying an alternating current to the heater is monitored, and the voltage cycle is monitored for a predetermined cycle. And a cycle detecting means for clearing the count value of the wave number counting means when no current flows through the heater.

According to a seventh aspect of the invention, in the heater control method, a heater temperature detecting means for detecting a temperature of the heater;
A heater control unit that controls a wave number of an alternating current supplied to the heater based on the temperature information of the heater temperature detection unit to control the heater to a predetermined temperature. Performing a wave number counting process for counting the number of waves of the alternating current that has been performed for each half-wave, and when the count value exceeds a predetermined value, interrupting the current supply to the heater and maintaining the interrupted state. Features.

In the heater control method according to an eighth aspect of the present invention, in the heater control method according to the seventh aspect, a time during which no AC current supplied to the heater flows is timed, and the timed value becomes equal to or greater than a predetermined value. Clearing the count value of the wave number counting process when

According to a ninth aspect of the present invention, in the heater control method according to the seventh aspect, a voltage cycle of an AC power supply for supplying an alternating current to the heater is monitored, and the voltage cycle is monitored for a predetermined cycle. When the current does not flow through the heater, the count value of the wave number counting process is cleared.

According to a tenth aspect of the present invention, there is provided a method for controlling a heat fixing heater of an electrophotographic recording apparatus, wherein a toner image forming means for exposing a photosensitive member to form a toner image on the exposed portion; An electrophotographic recording apparatus comprising: a transfer unit that transfers an image onto a recording medium; and a heat fixing unit that includes a heater and heat-fixes the toner image transferred onto the recording medium by heat generated from the heater. In the control method of the heater for heat fixing of the electrophotographic recording apparatus for controlling the temperature of the heater of the heat fixing means in the above, the process of detecting the temperature of the heater is performed, and the alternating current supplied to the heater based on the detected information. The current is controlled to control the heater to a predetermined temperature, and a wave number counting process for counting the number of waves of the alternating current supplied to the heater for each half wave is performed. When the count value exceeds a predetermined value, characterized in that it retains its interrupted state by interrupting the current supply to the heater.

According to an eleventh aspect of the present invention, in the method of controlling a heat fixing heater of an electrophotographic recording apparatus according to the tenth aspect, in the method of controlling a heat fixing heater of an electrophotographic recording apparatus, the alternating current supplied to the heater is controlled. It is characterized in that a time during which no current flows is counted, and when the counted value becomes equal to or more than a predetermined value, the count value of the wave number counting process is cleared.

According to a twelfth aspect of the present invention, in the method of controlling a heat fixing heater of an electrophotographic recording apparatus according to the tenth aspect, in the control method of the heat fixing heater of the electrophotographic recording apparatus, an alternating current is supplied to the heater. The present invention is characterized in that the voltage cycle of the supplied AC power is monitored, and when the current does not flow through the heater for a predetermined cycle, the count value of the wave number counting process is cleared.

[0029]

Embodiments of the present invention will be described below with reference to the drawings.

[First Embodiment] FIG. 1 is a circuit diagram showing a configuration of a heater control device according to a first embodiment of the present invention.

First, the configuration and operation of a portion mainly related to control of current supply to the ceramic heater will be described.

In FIG. 1, reference numeral 11 denotes an MPU,
M, RAM, timer, etc. MPU11
Has an output port PA0 and an analog input port AN0 having an A / D function of converting an analog voltage to a digital value and detecting the digital value.

Reference numeral 71 denotes the ceramic heater shown in FIG. 8, which has a resistor 71a and a thermistor 71b. The thermistor 71b has one terminal connected to the ground,
The other terminal is connected to the pull-up resistor 12 and the analog input port AN0 of the MPU 11, so that the MPU 11 detects the temperature of the ceramic heater 71.

Reference numeral 13 denotes a heater driver.
By operating the port PA0 of the PU 11, current supply / interruption to the resistor 71a can be performed. 14 is a commercial AC power supply, and 15 is a heater current cutoff circuit. The heater current cutoff circuit 15 cuts off / holds the state of the relay 15a based on the connection of the relay 15a when the power is turned on and error information from a heater current wave number counter 18 described later. The heater driver 13 and the commercial AC power supply 1
4 and the heater current cutoff circuit 15 have the same configuration functions as the heater driver 83, the commercial AC power supply 84, and the heater current cutoff circuit 85 of the conventional example shown in FIG.

In the above configuration, the MPU 11 intermittently supplies current to the resistor 71a based on temperature information of the thermistor 71b so as to control the temperature of the ceramic heater 71 to a predetermined temperature as in the conventional example. At this time,
Control that satisfies the two conditions is performed. 1) Thermistor 71b
Irrespective of the temperature information, the continuous supply of AC power of "half-wave × 15" or more is not performed. 2) The current supply suspension period is “half wave × 2” or more. That is, the ceramic heater 71
AC current is supplied intermittently at a maximum of 7 cycles (half wave × 14) on / one cycle off (half wave × 2).

Next, a part relating to the heater control abnormality detecting function will be described.

This function includes a heater current detection circuit 16,
A heater current pulse generation circuit 17, a heater current wave number counter 18, and a heater wave number counter taglia circuit 19 are involved. This will be described below with reference to the timing charts of FIGS. 2 and 3 together with FIG. FIG. 2 is a timing chart showing the normal operation, and FIG. 3 is a timing chart showing the operation when the heater control is abnormal.

The heater current detection circuit 16 comprises a current transformer 16a and a detection resistor 16b. When a heater current flows to the primary side of the current transformer 16a, the detection current flows and a voltage is generated across the detection resistor 16b. . One end of the detection resistor 16b is connected to a reference voltage Vref section of a heater current pulse generation circuit 17 described later.
The other end is input as a detection voltage Vin. As shown in the waveform diagram of FIG. 2, when the heater current is flowing, Vin becomes a sine wave centered on Vref.

The heater current pulse generating circuit 17 has a reference voltage Vr composed of a Zener diode 17a and a resistor 17b.
ef generating section and voltage dividing resistors 17c, 17d, 17e, 17
A threshold voltage generating unit that generates an upper threshold voltage Vhi and a lower threshold voltage Vlo based on f and comparators 17g and 17h compare these thresholds with an input voltage Vin from the heater current detection circuit 16 to generate a pulse CK1. And a window comparator section.

As shown in FIG. 2, Vin, Vhi, Vl
In the relationship of o, when the heater current flows, a pulse is generated for each half wave of the current. This pulse is connected to the clock input of the heater current wave number counter 18 and the asynchronous clear input of the heater wave number counter clear circuit 19.

The heater current wave number counter 18 is a counter circuit for detecting the continuation of heater current supply, and has a clock input CK1, an asynchronous clear input CL, and a ripple carry output RC1 (all of which have a negative logic).
It is set so that "L" is output to the ripple carry output RC1 when five shots, that is, when the heater current is input as "half wave x 15". And the ripple carry output RC1
Is connected to the Verr input of the heater current cutoff circuit 15, so that when "L" is output to RC1,
5a will be cut off / held. FIG. 3 shows a timing chart in this case.

The heater wave number counter clear circuit 19
Has a function of detecting the continuation of non-energization of the heater current and clearing the counter value of the heater wave number counter clear circuit 18. The oscillator circuit (OSC) 19a and the counter 19b for inputting its output to the clock CK2. It is configured. The counter 19b does not perform a counting operation because a pulse is always input to the asynchronous clear input CL (negative logic) when the heater current is flowing. Then, as shown in FIG. 2, when the heater current stops flowing, counting starts, and when four counts (time equal to or more than half a wave of the heater current and less than one wave) are counted, the ripple carry output RC2 is counted.
"L" is output to the heater wave number counter clear circuit 1
The counter value of 8 is cleared.

Therefore, if the energization of the ceramic heater 71 becomes continuous (half-wave × 15) due to runaway of the MPU 11, short-circuit of the triac of the heater driver 13, etc.
The heater current cutoff circuit 15 operates, and the ceramic heater 71
The power supply to the power supply is cut off quickly. In addition, since the current supply is determined at a half-wave or more, even when the triac has a half-wave conduction failure (half-wave × 15), the heater current cutoff circuit 15 operates.

As described above, in the present embodiment, even when abnormal energization of the ceramic heater 71 occurs, energization of the ceramic heater 71 can be quickly cut off without reaching an abnormally high temperature.

[Second Embodiment] FIG. 4 is a circuit diagram showing a configuration of a heater control circuit according to a second embodiment of the present invention.

The difference between the second embodiment and the above-described first embodiment is a portion relating to the heater wave number counter clear circuit 21, and other portions are denoted by the same reference numerals as in FIG. 1 of the first embodiment. The explanation is omitted. Hereinafter, a description will be given with reference to the timing charts of FIGS. FIG. 5 is a timing chart showing the operation at the time of normal operation, and FIG. 6 is a timing chart showing the operation at the time of abnormal heater control.

The heater wave number counter clear circuit 21 has a function of detecting the continuation of non-energization of the heater current and clearing the counter value of the heater wave number counter clear circuit 18.
It comprises an input power supply voltage frequency detection circuit 22 and a counter 23 for inputting its output to the clock CK3.

In the input power supply voltage frequency detection circuit 22, the input A is connected to the LED side of the photocoupler 22a via the resistor 22b.
By connecting the C power supply, the collector on the phototransistor side is connected to the power supply voltage Vcc, and the emitter is connected to the ground via the resistor 22c, the voltage Va shown in FIGS.
ch is generated on the semi-ground side of the resistor 22c.

The voltage Vach is output from the resistor 22.
The signal is input to the comparator 22f pulled up by g. The comparator 22f compares the voltage Vach with a threshold voltage Vth determined by the voltage dividing resistors 22d and 22e.
When ach> Vth, “L” is output. Accordingly, as shown in FIGS. 5 and 6, the output of the comparator 22f is a rectangular wave having the same cycle as the input voltage Vin. Then, this rectangular wave is input to the counter 23 as a clock CK3.

Since a pulse is always input to the asynchronous clear input CL (negative logic) when the heater current is flowing, the counter 23 does not perform the counting operation. Then, as shown in FIGS. 5 and 6, when the heater current stops flowing, the counting is started. When the counting is completed, "L" is output to the ripple carry output RC3 to clear the counter value of the heater wave number counter clearing circuit 18. I do. Where CK
By setting the threshold voltage Vth so that the pulse width of the “L side” of CK3 becomes wider than the pulse width of the “L side” of 1, the input power source Vin is reliably cleared by the first wave. I have.

As described above, in the present embodiment, the voltage cycle of the AC power supply is monitored, and the ceramic heater 7 is monitored for a predetermined cycle.
When the current does not flow through the counter 1, the counter value of the heater wave number counter clear circuit 18 is cleared. Even with such a configuration, similarly to the first embodiment, when abnormal energization to the ceramic heater 71 occurs, energization to the ceramic heater 71 can be quickly cut off without reaching an abnormally high temperature. .

FIG. 7 is a schematic sectional view showing an example of an electrophotographic recording apparatus equipped with the heater control device of the present invention.

This electrophotographic recording apparatus is constituted, for example, as a copying machine, and is equipped with the heater control device 300 realized in the first or second embodiment. In this copying machine, the ceramic heater of the fixing device 122 is
It is controlled by the heater control device 300.

In FIG. 7, reference numeral 100 denotes a copying apparatus main body;
00 is a circulating automatic document feeder that performs automatic document feeding,
That is, a feeder (hereinafter referred to as RDF) 250 is a sorting device, that is, a sorter, and these RDF 200 and sorter 250 can be freely combined with the main body 100 and used.

Reference numeral 101 denotes an original table glass as an original mounting table. Reference numeral 102 denotes an optical system as an image reading unit, which includes an original illumination lamp (exposure lamp) 103, a scanning mirror, a lens 143, a motor 104, and the like.
At 03, the original is illuminated, and reflected light from the original is irradiated on the photosensitive drum 105 by a scanning mirror and a lens.

Around the photosensitive drum 105, a primary charger 106, a blank exposure unit 107, a potential sensor 108, a developing device 109, a transfer charger 110,
A separation charger 111 is provided, and the photosensitive drum 105 and the like constitute an image forming unit.

The photosensitive drum 105 is connected to the main motor 11
3 rotates in the direction of the arrow shown in FIG. 5, is corona-charged by the primary charger 106, and
When the reflected light from the document 2 is emitted from 2, an electrostatic latent image is formed. This electrostatic latent image is developed by the developing device 109 and is visualized as a toner image.

On the other hand, the transfer paper sent from the upper cassette 114 or the lower cassette 115 into the main body 100 by the paper feed rollers 118 and 119 via the pickup rollers 116 and 117 is transferred to the registration roller 120 by the registration roller 120 so that the leading end of the toner image is transferred to the transfer paper. After the timing is set so that the leading edge of the toner image coincides with the leading edge of the photosensitive drum 105, the toner image is transferred to the photosensitive drum 105, and the toner image is transferred by the transfer charger 110. After this transfer,
The transfer paper is separated from the photosensitive drum 106 by a separation charger 111 and is fixed by a conveyance belt 121 to a fixing device 122.
(The temperature of the heater is controlled by the heater control device of the present invention.) The fixing is performed by pressurizing and heating, and then discharged outside the main body 100 by the discharge roller 123.

As described above, in the copying machine of the present embodiment, the first
Since the heater control device 300 realized in the embodiment or the second embodiment is mounted and the ceramic heater of the fixing device 122 is controlled by the heater control device 300, abnormal energization to the ceramic heater occurs. Even in this case, the power supply to the ceramic heater can be quickly shut off without reaching an abnormally high temperature,
Adverse effects on other components of the copying machine can be minimized.

[0060]

As described in detail above, according to the heater control device according to the first to third aspects of the present invention and the heater control method according to the seventh to ninth aspects,
Even when abnormal energization of the heater occurs, energization of the heater can be quickly shut off without reaching abnormally high temperatures.

According to the electrophotographic recording apparatus according to the fourth and sixth aspects of the present invention, and the control method of the heat fixing heater of the electrophotographic recording apparatus according to the tenth to the twelfth aspects of the present invention, Even when the heater of the fixing unit is abnormally energized, the energization of the heater can be quickly shut off without reaching an abnormally high temperature, thereby minimizing adverse effects on other members of the apparatus such as the thermal fixing unit. It becomes possible.

[Brief description of the drawings]

FIG. 1 is a circuit diagram showing a configuration of a heater control device according to a first embodiment of the present invention.

FIG. 2 is a timing chart showing a normal operation according to the first embodiment.

FIG. 3 is a timing chart showing an operation when a heater control is abnormal according to a second embodiment.

FIG. 4 is a circuit diagram showing a configuration of a heater control circuit according to a second embodiment of the present invention.

FIG. 5 is a timing chart showing a normal operation according to the second embodiment.

FIG. 6 is a timing chart showing an operation when a heater control is abnormal according to the second embodiment.

FIG. 7 is a schematic sectional view showing an example of an electrophotographic recording apparatus equipped with a heater control device of the present invention.

FIG. 8 is a sectional structural view of a film-type fixing device.

9 is a circuit diagram showing a heater control device of the film heating type fixing device shown in FIG.

[Explanation of symbols]

 11 MPU 13 heater driver 14 commercial AC power supply 15 heater current cutoff circuit 15a relay 16 heater current detection circuit 17 heater current pulse generation circuit 18 heater current wave number counter 19, 21 heater wave number counter taglia circuit 71 ceramic heater 71a resistor 71b thermistor 300 fixing vessel

Claims (12)

[Claims] 1. A heater temperature detecting means for detecting a temperature of a heater, and a wave number of an alternating current supplied to the heater is controlled based on temperature information of the heater temperature detecting means to control the heater to a predetermined temperature. A heater temperature control unit, a wave number counting unit that counts the number of waves of the alternating current supplied to the heater for each half-wave, and when the count value of the wave number counting unit becomes equal to or greater than a predetermined value, A heater control device, comprising: heater current interrupting means for interrupting current supply and maintaining the interrupted state. 2. The apparatus according to claim 1, further comprising: a timer for measuring a time during which no AC current supplied to the heater flows, and for clearing a count value of the wave number counting means when the measured value exceeds a predetermined value. The heater control device according to claim 1, wherein 3. A cycle detection that monitors a voltage cycle of an AC power supply that supplies an alternating current to the heater and clears a count value of the wave number counting means when a current does not flow through the heater for a predetermined cycle. 2. The heater control device according to claim 1, further comprising means. 4. A toner image forming means for exposing a photoreceptor to form a toner image on the exposed portion, a transfer means for transferring the toner image onto a recording medium, and a heater. An electrophotographic recording apparatus comprising: a heat fixing unit that heat-fixes the toner image transferred onto the recording medium by heat generated by the heating unit; and a heater control device that controls a temperature of the heater. Heater temperature detection means for detecting the temperature of the heater; and heater temperature control means for controlling the wave number of an alternating current supplied to the heater to control the heater to a predetermined temperature based on the temperature information of the heater temperature detection means. A wave number counting means for counting a wave number of the alternating current supplied to the heater for every half wave; and a count value of the wave number counting means is equal to or more than a predetermined value. Come to an electrophotographic recording apparatus characterized by comprising a heater current interrupting means to interrupt the current supply to retain its blocking state to the heater. 5. A time measuring means for measuring a time during which no AC current supplied to the heater flows, and for clearing a count value of the wave number counting means when the time value becomes equal to or more than a predetermined value. The electrophotographic recording apparatus according to claim 4, wherein 6. A cycle detection that monitors a voltage cycle of an AC power supply that supplies an alternating current to the heater and clears a count value of the wave number counting means when a current does not flow through the heater for a predetermined cycle. 5. An electrophotographic recording apparatus according to claim 4, further comprising means. 7. A heater temperature detecting means for detecting a temperature of a heater, and a wave number of an alternating current supplied to the heater is controlled based on temperature information of the heater temperature detecting means to control the heater to a predetermined temperature. For a heater control device having a heater temperature control means, a wave number counting process for counting the number of waves of the alternating current supplied to the heater for each half wave is performed, and when the count value becomes equal to or greater than a predetermined value, A heater control method, comprising interrupting current supply to a heater and maintaining the interrupted state. 8. The method according to claim 1, wherein a time during which no AC current is supplied to the heater is measured, and when the measured time exceeds a predetermined value, a count value of the wave number counting process is cleared. A heater control method according to claim 7. 9. A method of monitoring a voltage cycle of an AC power supply for supplying an alternating current to the heater and clearing a count value of the wave number counting process when a current does not flow through the heater for a predetermined cycle. The heater control method according to claim 7, wherein: 10. A toner image forming device for exposing a photosensitive member to form a toner image on an exposed portion thereof, a transferring device for transferring the toner image onto a recording medium, and a heater. Heat fixing means for controlling the temperature of the heater of the heat fixing means in an electrophotographic recording apparatus, the heat fixing means comprising: a heat fixing means for heat fixing the toner image transferred onto the recording medium by the heat generated. In the method for controlling a heater for, performing a process of detecting the temperature of the heater, controlling an alternating current supplied to the heater based on the detection information,
While controlling the heater to a predetermined temperature, a wave number counting process for counting the number of waves of the alternating current supplied to the heater for each half-wave is performed, and when the count value becomes equal to or more than a predetermined value, the heater is controlled. A method of controlling a heater for heat fixing of an electrophotographic recording apparatus, wherein the current supply is interrupted and the interrupted state is maintained. 11. The method according to claim 1, wherein a time during which no AC current is supplied to the heater is measured, and the count value of the wave number counting process is cleared when the measured time value exceeds a predetermined value. 11. The method for controlling a heat fixing heater of the electrophotographic recording apparatus according to item 10. 12. An AC for supplying an alternating current to the heater.
11. The heat of the electrophotographic recording apparatus according to claim 10, wherein a voltage cycle of a power supply is monitored and a count value of the wave number counting process is cleared when a current does not flow through the heater for a predetermined cycle. Control method of fixing heater.