JPH10333490A - Image forming device and power controlling method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an image forming device performing appropriate fixing control at a fixing means and power supply control at a main power source controlling means in accordance with the voltage of AC power inputted as main power from a commercial power source or the like. SOLUTION: A laser beam printer is constituted so as to discriminate whether the AC power inputted is 200 V system or 100 V system by a LPF 116 and a hysterisis comparator 117 and also an engine controller 130a by using the zero cross signal of a zero cross circuit 111, and a 'triac (R)' 151 is turned on and off so as to perform voltage doubler rectification or full wave rectification by a rectifying diode 102 or the like in accordance with a discriminated result, and in the engine controller 130a either of wave number control and phase control is selected as an energizing controlling system for the ceramic heater of a fixing unit in accordance with the discriminated result.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for forming a latent image corresponding to an input image on a latent image carrier, and visualizing the latent image formed on the latent image carrier as a developer image. The present invention relates to an image forming apparatus for forming an image on a transfer material by using an electrophotographic process of transferring a developer image to a transfer material and fixing the developer image to the transfer material, and a power control method used for the image forming apparatus.

[0002]

2. Description of the Related Art In general, there is an image forming apparatus such as a printer that prints print data from an external device on a sheet, using an electrophotographic process.

The configuration and operation of a laser beam printer, which is one of image forming apparatuses using this electrophotographic process, will be described with reference to FIG. FIG. 10 is a diagram schematically showing a configuration of a conventional laser beam printer.

As shown in FIG. 10, a laser beam printer 100 includes a detachable cassette 2 for storing recording paper S.
And the presence or absence of the recording paper S in the cassette 2 is detected by the cassette paper presence / absence sensor 3 and the size of the recording paper S in the cassette 2 is detected by the cassette size sensor 4 (composed of a plurality of micro switches). It is configured as follows. The recording paper S in the cassette 2 is sent out by the paper feed roller 5 toward the registration roller 6, and the registration roller 6 transfers the recording paper S to the photosensitive drum 17 in synchronization with the rotation of the photosensitive drum 17.
To the image forming unit 8 including

The image forming section 8 forms a toner image by visualizing the electrostatic latent image from forming an electrostatic latent image on the photosensitive drum 17 by using a laser beam scanned by the laser scanner section 7. The process up to the transfer to the recording paper S is performed. More specifically, the image forming unit 8 includes a photosensitive drum 17 on the surface of which an electrostatic latent image is formed by a laser beam scanned by the laser scanner unit 7, and a primary drum that charges the surface of the photosensitive drum 17 to a predetermined potential. A charging roller 19, a developing device 20 for visualizing an electrostatic latent image formed on the photosensitive drum 17 as a toner image, and a toner image on the photosensitive drum 17 on a recording sheet S fed by the registration roller 6. It comprises a transfer charging roller 21 for transferring, a cleaner 22 for removing residual toner and the like on the photosensitive drum after transfer, and the like.

The laser scanner unit 7 emits a laser beam modulated based on the image signal VDO output from the engine controller 130e, and scans the photosensitive drum 17 with the laser beam emitted from the laser unit 13. And a polygon mirror 14 for performing
The scanned laser light is guided onto the photosensitive drum 17 by the imaging lens group 15 and the folding mirror 16.

The recording paper S on which the toner image has been transferred is fixed to the fixing device 1.
The fixing device 120 fixes the toner image on the recording paper S by heat and pressure. By this fixing, an image of the input image data is formed on the recording paper S. The input fixing device 120 has a fixing film 123 in which a ceramic heater 121 is provided, and a pressure roller 124, and is configured to detect the surface temperature of the ceramic heater 121 with a thermistor 122.

The recording paper S on which the image has been formed is discharged onto a stacking tray 12 by discharge rollers 11. The conveyance state of the recording paper S from the fixing device 12 to the paper discharge roller 11 is configured to be detected by the paper discharge sensor 10.

The main motor 23 drives the paper feed roller 5, the registration roller 6, the photosensitive drum 17, the pressure roller 124 of the fixing device 120, and the paper discharge roller 11. The driving force of the main motor 23 is applied to the sheet feeding roller 5 via a sheet feeding clutch 24 and the registration roller 6 via a registration clutch 25, respectively.

The engine controller 130e controls the image forming process of the electrophotographic system by the laser scanner unit 7, the image forming unit 8, and the fixing unit 120, and controls the conveyance of the recording paper S. Engine controller 1
Reference numeral 30e performs power supply control to the ceramic heater 121 of the fixing device 120 in addition to the above control. The image signal VDO input to the laser scanner unit 7 from the engine controller 130e is a signal output from the video controller 27.

An external device 31 such as a personal computer is connected to the video controller 27 via a general-purpose interface (Centronics, RS232C, etc.) 30. The video controller 27 takes in the image information sent from the external device 31 through the general-purpose interface 30, develops the image information into bit data, and sends the harmful bit data as an image signal VDO to the engine controller 130e.

In the apparatus main body, the temperature rises due to heat radiated from the ceramic heater 121 of the fixing device 120 and the like, and a fan 29 for suppressing this temperature rise is provided.

The above-described laser scanner section 7, image forming section 8, main motor 23, engine controller 130
e, the ceramic heater 121 of the fixing device 120, etc.
Driving force corresponding to each is supplied from main power control means (not shown). The main power supply control unit performs power supply control for converting the input AC power into drive power for each unit and supplying the drive power.

Next, the configuration of the main power supply circuit of the main power supply control means in the laser beam printer 100 will be described with reference to FIGS. 11 and 12
FIG. 13 is a diagram showing a main power supply circuit configuration of main power supply control means in the laser beam printer of FIG. 10, FIG. 13 is a diagram showing a rectifier diode and a peripheral circuit configuration in the main power supply circuit of FIG. 12, and FIG. It is a figure which shows the waveform of an electric power, and the heater conduction waveform by each of wave number control and phase control.

FIGS. 11 and 12 show the main power control means.
As shown in the figure, a main power supply circuit is provided, and the main power supply circuit converts the input AC power into drive power for each unit (the laser scanner unit 7, the image forming unit 8, the main motor 23, the engine controller 130e, and the like). A power supply circuit portion that converts and supplies power is roughly classified into a heater power supply circuit portion that supplies power to the ceramic heater 121 of the fixing device 120.

As shown in FIG. 12, the power supply circuit includes an AC line filter 101 for input AC power, a rectifier diode (diode bridge) 102, smoothing capacitors 103 and 104, a low-voltage power supply unit 105, and a slide switch (hereinafter, referred to as a slide switch). Switch 301). The AC power after passing through the AC line filter 101 is rectified and smoothed by a rectifier diode (diode bridge) 102 and smoothing capacitors 103 and 104.
The smoothed voltage is input to the low-voltage power supply unit 105. The low-voltage power supply unit 105 converts the input voltage into each DC voltage such as 24 V and 5 V, and converts each DC voltage into each unit (the laser scanner unit 7, the image forming unit 8, the main motor 23, the engine controller 130e, the video controller 27, and the like). Supplied to The switch 301 is switched in accordance with the voltage of the input AC power. The switch 301 is turned on when inputting 100 V AC power such as in North America, and when inputting 200 V AC power such as in Europe. Is switch 3
01 are each switched off. Switch 301
Is in the ON state, voltage doubler rectification is performed by the rectifier diode 102 and the smoothing capacitors 103 and 104. When the switch 301 is in the OFF state, full-wave rectification is performed by the rectifier diode 102 and the smoothing capacitors 103 and 104. Will be

A rectifier circuit configuration formed by the rectifier diode 102, the smoothing capacitors 103 and 104, and the switch 301 will be specifically described with reference to FIG.

The switch 106 (switch 3 shown in FIG. 12)
01 (corresponding to 01) is in the off state, as shown in FIG.
03 and 104 form a full-wave rectifier circuit, but the description of the current flow when the full-wave rectifier circuit is formed is omitted.

On the other hand, when the switch 106 (corresponding to the switch 301 shown in FIG. 12) is off, the rectifier diode 102 and the smoothing capacitors 103, 1
04 and the switch 106 form a voltage doubler rectifier circuit. The current flowing from point a in the figure is
To charge the smoothing capacitor 104 through the diode D4 in the rectifier diode 102 and return to the middle point b. Conversely, the current flowing from b in the figure passes through the diode D3 in the rectifier diode 102, charges the smoothing capacitor 103, passes through the switch 106, and returns to the point a in the middle. As described above, since the charges are charged in the smoothing capacitors 103 and 104 with respect to the positive and negative of the AC power, the voltage stored in each of the smoothing capacitors 103 and 104 is at the time of full-wave rectification (when the switch 106 is off). Double. In the double voltage rectification when the switch 106 is turned on,
Only the diodes D3 and D4 of the rectifier diode 102 will be used.

As described above, the switching operation is performed in accordance with the voltage of the AC power input to the switch 301 to input 100 V AC power in North America or the like, or to input 200 V AC power in Europe or the like. Can be handled.

An AC line filter 131 is provided in a heater power supply circuit portion for supplying power to the ceramic heater 121 of the fixing device 120, as shown in FIG.
The AC power after passing through the C line filter 131 is supplied to the ceramic heater 121. Ceramic heater 121
Is supplied to the triac 1 based on the surface temperature of the ceramic heater 121, that is, the detected voltage of the thermistor 122.
It is controlled by turning on / off 33. The detected voltage of the thermistor 122 (the voltage divided by the resistor 162) is input to the A / D port of the engine controller 130e (A / D port of the CPU in the engine controller) shown in FIG. You. The engine controller 130e applies a control voltage for turning on / off the transistor 139 based on the detected voltage value of the thermistor 122 to the base of the transistor 139 from the I / O port via the resistor 141. Operates on / off. The base and the emitter of the transistor 139 are connected by a resistor 142 inserted in parallel.

When the transistor 139 is turned on, the power supply voltage Vcc is applied to the resistor 138 and the triac photocoupler 1
A current path extending between the light emitting diode 37 and the collector-emitter of the transistor 139 is formed, and the triac photocoupler 137 is turned on. Specifically, the light emitting diode of the triac photocoupler 137 emits light and the light receiving transistor turns on. That is, the triac photocoupler 137 turns on. When the transistor 139 turns off, the current path between the collector and the emitter of the transistor 139 is cut off, and the triac photocoupler 137 turns off. As the triac photocoupler 137 is turned on / off, the triac 133 is turned on / off by a gate current from a gate circuit composed of the resistors 136 and 135 and the capacitor 134.

The timing for turning on / off the triac 133, that is, turning on / off the transistor 139
The output timing of the control voltage for the off drive is determined based on the zero-cross timing of the input AC power. That is, as shown in FIG. 12, the AC power after passing the AC line filter is input to the zero cross circuit 111 via the rectifier diode 110, and the zero cross circuit 111 detects the zero cross point of the input AC power, and Control is performed to turn on the photocoupler 113. Specifically, a base voltage is applied to turn on the transistor 114, and the transistor 114 is turned on.
Turns on. When the transistor 114 is turned on, a current path returning from the zero cross circuit 111 to the resistor 112, the light emitting diode of the photocoupler 113, and the zero cross circuit 111 via the transistor 114 is formed, and the light emitting diode is turned on. When the light emitting diode is turned on, the light receiving diode is turned on, and the voltage divided by the resistor 115 is applied to the resistor 305.
Through the I / O of the engine controller 130e. The engine controller 130e controls this I / O
, The zero-cross timing of the input AC power is detected based on the voltage input through the circuit, and a base voltage for turning on / off the transistor 139 is output based on this timing.

As described above, in the configuration of the heater power supply circuit portion, the power supplied to the ceramic heater 121 is controlled by the triac 133 by the engine controller 130e.
Is controlled by the on / off ratio of The on / off control of the triac 133 is performed based on the detected voltage of the thermistor 122, and the on / off timing of the triac 133 is determined based on the zero-cross timing of the input AC power. Methods for controlling the energization of the ceramic heater 121 by turning on / off the triac 133 include wave number control and phase control, and the wave number control is control to turn on / off for each input AC power wave. According to this control, if the waveform of the input AC power is the waveform shown in FIG. 14A, the current supplied to the ceramic heater 121 has the waveform shown in FIG. 14B. On the other hand, the phase control is a method of controlling the conduction angle of the input AC power, and the current supplied to the ceramic heater 121 has a waveform as shown in FIG.

The wave number control has the characteristic that the harmonic current is small but the flicker noise is large, and the phase control has the characteristic that the flicker noise is small but the harmonic current is large. , One of wave number control and phase control is set as a control method according to the voltage of the input AC power.

[0026]

However, as described above, when a switch operation is performed in accordance with the voltage of the AC power input to the switch 301, when a 100V AC power input in North America or the like is input, a switch in Europe or the like is used. Although it is possible to cope with each case of inputting 200V AC power, the switch 301 according to the voltage of the input AC power is used.
Is required. In addition, since either one of the wave number control and the phase control is set as the control method according to the voltage of the input AC power to the engine controller 130e, the 100V AC power of North America or the like is input. In such a case, it is not possible to cope with the case where 200 V AC power is input, such as in Europe.

An object of the present invention is to provide an image forming apparatus capable of performing fixing control in an appropriate fixing unit and power supply control in a main power supply control unit in accordance with the voltage of AC power input as main power from a commercial power supply or the like. An object of the present invention is to provide a power control method.

[0028]

According to the first aspect of the present invention,
Latent image forming means for forming a latent image corresponding to the input image on the latent image carrier, developing means for visualizing the latent image formed on the latent image carrier as a developer image, and transfer Transfer means for transferring the developer image to a material, fixing means for fixing the developer image to the transfer material, and converting AC power input from outside into drive power corresponding to each of the means, An image forming apparatus comprising: a main power supply control unit that performs power supply control for supplying the power to each of the units; a detection unit that detects a time when an absolute value of the input AC power is smaller than a predetermined value near zero; Determining means for determining a voltage value of the input AC power based on a detection result of the detecting means, wherein the determination result of the determining means is used for fixing control in the fixing means and power supply control in the main power control means. And it features.

According to a second aspect of the present invention, in the image forming apparatus according to the first aspect, the fixing control using the determination result of the determining unit includes a plurality of temperatures for fixing the developer image on the transfer material. The power supply control using the determination result of the determination unit is configured to selectively switch a control mode based on a determination result of the determination unit. It is characterized by comprising a control for switching a plurality of power conversion modes based on a result of the determination by the determination means.

According to a third aspect of the present invention, in the image forming apparatus according to the second aspect, the plurality of temperature control modes are provided in the fixing unit by turning on and off the input AC power. It is a mode for controlling a power supply amount to a heater.

According to a fourth aspect of the present invention, in the image forming apparatus according to the third aspect, power is supplied to a heater provided in the fixing unit by turning on or off at each wave number of the input AC power. A first temperature control mode for controlling the amount of power and a second temperature control mode for controlling the amount of power supplied to the heater provided in the fixing unit by changing the conduction angle of the input AC power. Power supply control means for setting and executing one of the first temperature control mode and the second temperature control mode based on the determination result of the determination means. I do.

According to a fifth aspect of the present invention, in the image forming apparatus according to the second aspect, in the plurality of power conversion modes, the input AC power is converted into drive power for the respective units after full-wave rectification of the input AC power. It is characterized by comprising a first power conversion mode and a second power conversion mode in which the input AC power is double-voltage rectified and then converted into drive power for the respective means.

According to a sixth aspect of the present invention, in the image forming apparatus of the fifth aspect, a first rectifier for full-wave rectifying the input AC power, and a voltage doubler rectification of the input AC power. A second rectifier, a converter for converting electric power from one of the first rectifier and the second rectifier into drive power for each of the units, and a converter based on a determination result of the determiner. One of the first rectifier and the second rectifier is selected so as to execute one of the first power conversion mode and the second power conversion mode. And a conversion mode switching means for selectively switching.

According to a seventh aspect of the present invention, in the image forming apparatus of the sixth aspect, when the AC power is input, the conversion mode switching means is set to select the first rectification means. It is characterized by.

According to an eighth aspect of the present invention, in the image forming apparatus of the first aspect, the judging unit averages a low-pass filter for averaging the detection result of the detecting unit and the low-pass filter. A hysteresis comparator for comparing the detection result with a preset predetermined value, wherein a voltage value of the input AC power is determined based on a comparison result by the hysteresis comparator.

According to a ninth aspect of the present invention, there is provided a latent image forming means for forming a latent image corresponding to an input image on a latent image carrier,
Developing means for visualizing the latent image formed on the latent image carrier as a developer image, transfer means for transferring the developer image to a transfer material, and fixing the developer image to the transfer material An image forming apparatus comprising: a fixing unit for causing the image forming apparatus to convert AC power input from the outside into driving power corresponding to each of the units; and a main power supply control unit for performing power supply control for supplying the driving power to the units. In the power control method used, a time when the absolute value of the input AC power is smaller than a predetermined value near zero is detected, and a voltage value of the input AC power is determined based on the detection result. It is used for fixing control in the fixing unit and power supply control in the main power control unit.

According to a tenth aspect of the present invention, in the power control method according to the ninth aspect, the fixing control using the determination result includes a plurality of temperature control modes for fixing the developer image on the transfer material. The power supply control using the determination result includes a plurality of power conversion modes for converting the input AC power into drive power for the respective units. Characterized in that the switching is performed based on

According to an eleventh aspect of the present invention, in the power control method according to the tenth aspect, the plurality of temperature control modes are provided in the fixing unit by turning on and off the input AC power. It is a mode for controlling a power supply amount to a heater.

According to a twelfth aspect of the present invention, in the power control method according to the eleventh aspect, power is supplied to a heater provided in the fixing means by turning on or off at each wave number of the input AC power. A first temperature control mode for controlling the amount of power and a second temperature control mode for controlling the amount of power supplied to the heater provided in the fixing unit by changing the conduction angle of the input AC power. Set,
One of the first temperature control mode and the second temperature control mode is selected and executed based on the determination result.

According to a thirteenth aspect of the present invention, in the power control method according to the tenth aspect, in the plurality of power conversion modes, the input AC power is full-wave rectified and then converted into drive power for the respective means. A first power conversion mode, and a second power conversion mode in which the input AC power is double-voltage rectified and then converted into drive power for the respective units, and the first power conversion is performed based on the determination result. And executing either one of the power conversion mode and the second power conversion mode.

According to a fourteenth aspect of the present invention, in the power control method according to the thirteenth aspect, when the AC power is input,
The input AC power is set to be full-wave rectified.

According to a fifteenth aspect of the present invention, in the power control method according to the ninth aspect, the detection result is averaged by a low-pass filter, and the averaged detection result and a predetermined value are set by a hysteresis comparator. And the voltage value of the input AC power is determined based on the comparison result.

[0043]

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

(First Embodiment) FIG. 1 is a view schematically showing the configuration of a first embodiment of the image forming apparatus of the present invention. In the present embodiment, an example will be described in which the principle of the present invention is applied to the laser beam printer (shown in FIG. 10) described in the “Prior Art” section. Therefore, in this embodiment, components different from those of the laser beam printer shown in FIG. 10 will be described, and the same components will be denoted by the same reference numerals.
The description is simplified or omitted.

As shown in FIG. 1, the laser beam printer 100 controls the image forming process of the electrophotographic method by the laser scanner unit 7, the image forming unit 8, and the fixing unit 120, controls the conveyance of the recording paper S, and controls the fixing unit 120. An engine controller 130a for controlling power supply to the ceramic heater 121, and an AC power input from a commercial power supply are supplied to the respective units (the laser scanner unit 7, the image forming unit 8,
And a power supply unit (not shown) for converting and supplying drive power to the main motor 23 and the engine controller 130a.

Next, the circuit configuration of the main power supply control means in the laser beam printer 100 will be described with reference to FIGS. 2 and 3 are diagrams showing a main power supply circuit configuration of main power control means in the laser beam printer of FIG. 1. FIG. 4 is a diagram showing a rectified waveform and a zero cross signal of AC power input to the laser beam printer of FIG. FIG. 5 is a circuit diagram showing the configuration of the zero cross circuit of FIG.

As shown in FIGS. 2 and 3, the main power supply control means is provided with a main power supply circuit. The main power supply circuit supplies the AC power input from the commercial power supply to each unit (the laser scanner unit 7, A power supply circuit portion that converts and supplies drive power to the image forming unit 8, the main motor 23, the engine controller 130 e, and the like) and a heater power supply circuit portion that supplies power to the ceramic heater 121 of the fixing device 120. Is done.

As shown in FIG. 3, an AC line filter 101 for input AC power, a rectifier diode (diode bridge) 102, smoothing capacitors 103 and 104, a low-voltage power supply unit 105, and a triac 151 are provided in the power supply circuit. Have been. AC line filter 1
01 is rectified and smoothed by a rectifier diode (diode bridge) 102 and smoothing capacitors 103 and 104, and the smoothed voltage is supplied to a low-voltage power supply unit 105.
Is input to The low-voltage power supply unit 105 converts the input voltage to 24
Vc, Vc, etc., and the power supply voltage Vc
c is supplied to each unit (laser scanner unit 7, image forming unit 8, main motor 23, engine controller 130a, video controller 27, etc.). Triac 15
1 is ON / OFF controlled in accordance with the voltage of the input AC power. When a 100 V AC power is input in North America or the like, the triac 151 is turned on. When a 200 V AC power is input in Europe or the like. Is controlled so that the triac 151 is turned off. When the triac 151 is on, the rectifier diode 102 and the smoothing capacitors 103 and 104 perform voltage doubler rectification. When the triac 151 is off, the rectifier diode 102 and the smoothing capacitors 103 and 104 perform full-wave rectification. Is performed. The details of the rectification operation by the rectifier diode 102, the smoothing capacitors 103 and 104, and the triac 151 are the same as the operation described with reference to FIG. 13 described above, and a description thereof will be omitted. FIG.
The switch 106 in No. 3 corresponds to the triac 151.

As described above, the switching of the triac 151 is performed in accordance with the voltage of the input AC power, and the voltage of the AC power is determined based on the output from the zero-cross circuit 111. The AC power that has passed through the AC line filter 101 is supplied to the zero-cross circuit 111 by the rectifier diode 1.
The zero-crossing circuit 111 detects a zero-crossing point of the input AC power and outputs a zero-crossing signal to turn on the photocoupler 113 in accordance with the timing of the detection.

As shown in FIG. 5, the zero-cross circuit 111 is provided with a resistor 171, a Zener diode 172, and a capacitor 173. The resistor 171, the Zener diode 172, and the capacitor 173 are connected to a point e on the output side of the rectifier diode 110. It is connected in series with the point f. Zener diode 172 and capacitor 173
The base of the transistor 114 is connected to the line between the capacitor 173 and the transistor 114.
A resistor 174 is connected in parallel with the capacitor 173 to the line between the bases.

In such a circuit configuration, the voltage value (voltage value between points ef) indicated by the waveform of the AC power rectified by the rectifier diode 110 is a predetermined value (a predetermined value near zero and the Zener diode 172). (The value obtained by adding the Zener voltage of the transistor 114 to the voltage between the base and the emitter of the transistor 114), the base voltage is applied to the transistor 114, and the transistor 114 is turned on. When the transistor 114 is turned on, the zero-cross circuit 111 (point g) is turned on through the resistor 112, the light-emitting diode of the photocoupler 113, and the zero-cross circuit 11 via the transistor 114.
A current path returning to 1 (point i) is formed, and the light emitting diode, that is, the photocoupler 113 is turned on. Photo coupler 1
13 turns on, a zero-cross signal (“H” level zero-cross signal) of a voltage value divided by the resistor 115 is applied to the resistor 1.
18 and input to the I / O of the engine controller 130a, and the zero-cross signal is
(Low-pass filter) 116. When the voltage value (voltage value between points ef) of the waveform of the AC power rectified by the rectifier diode 110 becomes equal to or less than the predetermined value, the transistor 114 turns off and the photocoupler 113 turns off. By turning off the photocoupler 113, the zero-cross signal input to the engine controller 130a and the LPF 116 becomes an "L" level signal.

For example, as shown in FIG.
Assuming that a waveform rectified by the rectifier diode 110 with respect to the V-system AC power is a, the transistor 114 is turned on / off depending on whether the voltage value of the waveform a exceeds the predetermined value VTH, and the photocoupler 113 is turned on. Turn on / off. The level of the zero-cross signal changes to “H” level or “L” level by turning on / off the photocoupler 113 as shown in FIG. 4B. Similarly, FIG.
As shown in (c), if the waveform rectified by the rectifier diode 110 with respect to the AC power of 100V system is represented by b,
The level of the zero-cross signal changes to “H” level or “L” level depending on whether the voltage value of the waveform b has exceeded the predetermined value VTH. As can be seen from the figure, in the zero-cross signal, the "L" level pulse width for 200 V AC power is smaller than the "L" level pulse width for 100 V AC power. Therefore, by detecting the pulse width of the "L" level, a time period in which the absolute value of the input AC power becomes smaller than a predetermined value near zero is detected. Voltage, that is, the input AC power is 20
It can be determined whether the system is a 0V system or a 100V system.

LPF 116 to which a zero-cross signal is input
Then, as shown in FIG. 3, the zero cross signal is converted into a DC voltage, and this DC voltage is input to the hysteresis comparator 117. Hysteresis comparator 117
Integrates the input DC voltage for a predetermined time, compares the integrated value with a preset reference value, and sets a base voltage for turning on / off the transistor 158 via the resistor 158 according to the comparison result. 158 applied to the base. Specifically, when the integrated value of the input DC voltage is equal to or less than the reference value, the input AC power becomes 100
A base voltage is applied so as to turn on the transistor 158 by determining that the power is V-system AC power, and when the integrated value of the input DC voltage is larger than the reference value, the input AC power is 200 V-system AC power. It is set so that the application of the base voltage is stopped so that it is determined that there is, and the transistor 158 is turned off. Here, the reason why the hysteresis comparator 117 is used is to avoid that the output of the LPF 116 approaches the reference value and the operation of the transistor 157 is not determined.

The emitter of the transistor 157 is grounded to the reference potential, and the emitter and the base of the transistor 157 are connected by a resistor 159 inserted in parallel. When the transistor 157 is turned on, a current path from the power supply voltage Vcc to the resistor 156, the light emitting diode of the triac photocoupler 155, and the collector-emitter of the transistor 157 is formed.
5 turns on. Specifically, the light emitting diode of the triac photocoupler 155 emits light and the light receiving transistor turns on. That is, the triac photocoupler 155 turns on. When the transistor 157 turns off, the current path between the collector and the emitter of the transistor 157 is cut off, and the triac photocoupler 155 turns off. As the triac photocoupler 155 is turned on / off, the triac 151 is turned on / off by a gate current from a gate circuit composed of the resistors 154 and 153 and the capacitor 152.

When the triac 151 is turned on, as described above, the rectifier diode 102 and the smoothing capacitors 103 and 104 are applied to the input 100 V AC power.
When the triac 151 is in the off state, the rectifier diode 102 and the smoothing capacitor 10 with respect to the input 200 V AC power.
3 and 104 perform full-wave rectification. In this way, by controlling the switching of the triac 151 according to the voltage of the input AC power, it is possible to control
When inputting 0V AC power, 200V in Europe etc.
It is possible to automatically cope with each case of inputting AC power of the system.

When 200 V AC power is input in a state where the triac 151 is turned on (a state where voltage doubler rectification is set), unnecessarily large voltages are applied to the smoothing capacitors 103 and 104 and the low-voltage power supply unit 105. It is preferable to provide a circuit for holding the triac 151 in the off state during the period from the input of the AC power to the rise of the power supply voltage Vcc in order to prevent the application of the triac 151 from occurring.

As shown in FIG. 2, an AC line filter 131 is provided in a heater power supply circuit for supplying power to the ceramic heater 121 of the fixing device 120.
AC power that has passed through the line filter 131 is supplied to the ceramic heater 121. The energization of the ceramic heater 121 is controlled by turning on / off the triac 133 based on the detection voltage of the thermistor 122. The detected voltage of the thermistor 122 (voltage divided by the resistor 162) is input to the A / D port of the engine controller 130a (A / D port of the CPU in the engine controller) shown in FIG. You. The engine controller 130a is connected to the thermistor 12
A base voltage for turning on / off the transistor 139 based on the detected voltage value of
The voltage is applied to the base of the transistor 139 via 41, and the transistor 139 is turned on / off by this base voltage. When the transistor 139 turns on, the triac photocoupler 137 turns on, and when the transistor 139 turns off, the triac photocoupler 137 turns off. As the triac photocoupler 137 is turned on / off, the triac 133 is turned on / off by a gate current from a gate circuit composed of the resistors 136 and 135 and the capacitor 134.

The on / off control of the triac 133 is performed based on the detection voltage of the thermistor 122, and the on / off timing of the triac 133 is determined based on the zero-cross timing of the input AC power. The zero-cross timing of the input AC power is detected based on the zero-cross signal (the waveform shown in FIG. 4B or 4C) of the above-described zero-cross circuit 111. The power supplied to the ceramic heater 121 is controlled by the on / off ratio of the triac 133 by the engine controller 130a.

A method for controlling the energization of the ceramic heater 121 by turning on / off the triac 133 includes wave number control and phase control, and the engine controller 130a supplies AC power for inputting wave number control and phase control wave number control to the engine controller 130a. It is set to be executed by switching according to the voltage. The details of the wave number control and the phase control are as described in the section of the related art, and the description thereof will be omitted. Specifically, the engine controller 130a
The pulse width of the "L" level of the zero-cross signal taken from the / O port is detected, and the detected pulse width is compared with a predetermined value set in advance. It is determined whether the power is AC power or 200 V AC power, and one of the wave number control and the phase control is selected and executed according to the determination result. When the "L" level pulse width of the zero cross signal taken from the I / O port exceeds the predetermined value, it is determined that the input AC power is 100 V AC power, and phase control is selected and executed. If the “L” level pulse width of the zero-cross signal is equal to or smaller than the predetermined value, it is determined that the input AC power is 200 V AC power, and the wave number control is selected and executed.

As described above, regarding the energization control to the ceramic heater 121 of the fixing device 120, it is determined whether the input AC power is 100V AC power or 200V AC power based on the zero cross signal. Since either one of the wave number control and the phase control is selected and executed in accordance with the determination result, the energization suitable for inputting 100 V AC power and inputting 200 V AC power, respectively. The control method can be automatically selected and executed.

(Second Embodiment) Next, a second embodiment of the present invention will be described with reference to FIG. FIG. 6 is a diagram showing a main power supply circuit configuration of main power control means in the second embodiment of the image forming apparatus of the present invention. Note that, in the present embodiment, a laser beam printer is used in the same manner as in the above-described first embodiment. In this embodiment, components different from those in the first embodiment will be described. The reference numerals are attached, and the description is simplified or omitted.
FIG. 6 shows a power supply circuit portion in the main power supply circuit which converts input AC power into drive power for each section and supplies the drive power, and a heater power supply circuit portion which supplies power to the ceramic heater 121 of the fixing device 120. Is the same as the circuit configuration shown in FIG. 2, and this circuit configuration is omitted.

In the present embodiment, a control signal for switching the triac 151 is generated in the primary circuit of the photocoupler 113, and the triac 151 is turned on / off using this control signal. They differ in that they operate.

More specifically, as shown in FIG. 6, a control signal for switching the triac 151 is transmitted from the zero cross circuit 111 (point g) via the resistor 112, the light emitting diode of the photocoupler 113, and the transistor 114 to the zero cross circuit 111. It is generated by the primary circuit of the photocoupler 113 up to (point i). In this primary side circuit, when the voltage value of the AC power rectified by the rectifier diode 110 (the voltage value between points ef) exceeds a predetermined value, the transistor 114 is turned on and the zero cross circuit 111 (point g) is turned on. A resistor 112, a light emitting diode of a photocoupler 113,
A current path returning to the zero cross circuit 111 (point i) via the transistor 114 is formed, and an "H" level control signal is generated. On the other hand, the voltage value of the AC power rectified by the rectifier diode 110 (voltage value between points ef)
Is less than the predetermined value, the light emitting diode is turned off by turning off the transistor 114, and an "L" level control signal is generated.

This control signal is converted into a DC voltage by the LPF 181, and this DC voltage is applied to the hysteresis comparator 18.
In step 2, the value is compared with a preset reference value. Based on the comparison result, a base voltage for turning on / off the transistor 184 is applied to the base of the transistor 184 via the resistor 183, and the transistor 184 turns on / off. When the transistor 184 is turned on / off, the resistance 15
4, 153 and a capacitor 152 generate a gate current, and the triac 151 is turned on / off by the gate current.

As described above, since the control signal of the triac 151 is generated by the above-described primary circuit, the circuit configuration can be simplified.

(Third Embodiment) Next, a third embodiment of the present invention will be described with reference to FIG. FIG. 7 is a diagram showing a main power supply circuit configuration of a main power control unit in a third embodiment of the image forming apparatus of the present invention. Note that, in the present embodiment, a laser beam printer is used in the same manner as in the above-described first embodiment. In this embodiment, components different from those in the first embodiment will be described. The reference numerals are attached, and the description is simplified or omitted.
FIG. 7 shows a power supply circuit portion in the main power supply circuit which converts the input AC power into drive power for each section and supplies the drive power, and a heater power supply circuit portion which supplies power to the ceramic heater 121 of the fixing device 120. Is the same as the circuit configuration shown in FIG. 2, and this circuit configuration is omitted.

The present embodiment differs from the first embodiment in that a control signal for switching the triac 151 is generated by the engine controller 130c, and the triac 151 is turned on / off using this control signal. different.

Specifically, as shown in FIG. 7, the engine controller 130c determines whether the input AC power is 100V AC power or 200V AC power based on the zero cross signal taken from the I / O port. It is determined whether or not there is, and a base voltage for turning on / off the transistor 157 is generated according to the determination result, and one of the wave number control and the phase control is selected and executed. When the pulse width of the “L” level of the zero-cross signal fetched from the I / O port exceeds the predetermined value, it is determined that the input AC power is 100 V AC power and the transistor 157 is turned on. When a base voltage is applied via a resistor 158 and the integrated value of the input DC voltage is larger than the reference value, it is determined that the input AC power is 200 V AC power and the base 157 is turned off so that the transistor 157 is turned off. A setting for stopping the application of the voltage and a setting for stopping the application of the base voltage so that the triac 151 is kept in the off state during the period from the input of the AC power to the rise of the power supply voltage Vcc. Has been made.

The triac photocoupler 155 is turned on / off as the transistor 157 is turned on / off, and the gate current of the triac 151 is controlled by turning on / off the triac photocoupler 155.
1 turns on / off. When the triac 151 is turned on, as described above, the rectifier diode 102 and the smoothing capacitor 103,
Voltage rectification is performed by the
When 1 is in the off state, full-wave rectification is performed on the input 200 V AC power by the rectifier diode 102 and the smoothing capacitors 103 and 104.

Since the switching control of the triac 151 is performed by the engine controller 130c, the configuration of the main power supply circuit can be simplified.

The contents of the selection control of the wave number control or the phase control using the zero cross signal are the same as those in the first embodiment, and the description thereof will be omitted.

(Fourth Embodiment) Next, a fourth embodiment of the present invention will be described with reference to FIGS. FIG. 8 is a diagram showing a configuration of a main power supply circuit of a main power supply control unit according to a fourth embodiment of the image forming apparatus of the present invention, and FIG. 9 is a circuit diagram showing a configuration of a starting circuit in the main power supply circuit of FIG. Note that, in the present embodiment, a laser beam printer is used in the same manner as in the above-described first embodiment. In this embodiment, components different from those in the first embodiment will be described. The reference numerals are attached, and the description is simplified or omitted. FIG. 8 shows a power supply circuit portion of the main power supply circuit which converts the input AC power into drive power for each section and supplies the drive power, and a heater power supply circuit portion which supplies power to the ceramic heater 121 of the fixing device 120. Is the same as the circuit configuration shown in FIG. 2, and this circuit configuration is omitted.

As described in the first embodiment, it is preferable that the triac 151 be kept in the off state during the period from the input of the AC power to the rise of the power supply voltage Vcc. Triac 1 during the period from the input of power to the rise of power supply voltage Vcc
A description will be given of a main power supply circuit configuration provided with a start-up circuit for holding 51 in an off state.

Specifically, as shown in FIG.
8 and the base of the transistor 157, the starting circuit 19
1 is connected in parallel with the resistor 158, and the starting circuit 191 is configured to hold the triac 151 in the off state during the period from the input of the AC power to the rise of the power supply voltage Vcc, and the base of the transistor 157 is connected to the resistor 15
9 and a diode 198 to the reference potential.

As shown in FIG. 9, the starting circuit 191 includes:
Two transistors 192 and 193 are provided, and the emitter of the transistor 192 is connected to the resistor 158 and the transistor 1.
The collector is connected to a reference potential and the collector is connected to the line connecting the base 57. The base of the transistor 192 is connected to a line connecting the resistor 194 and the emitter of the transistor 193, and the emitter of the transistor 193 is connected to the power supply voltage Vcc via the resistor 194.
The collector of the transistor 193 is grounded to the reference potential,
Its base consists of a resistor 196 and a Zener diode 19
5 and connected to the power supply voltage Vcc.
It is grounded to a reference potential via a capacitor 197.
The base voltage required to turn on transistor 192 is set lower than the base voltage required to turn on transistor 157 by a voltage corresponding to the internal resistance of diode 198.

In this starting circuit 191, the base voltage required to turn on transistor 192 is
Since it is set lower than the base voltage required to turn on the power supply 57 by the voltage corresponding to the internal resistance of the diode 198, the power supply of the device, that is, the time from the input of the AC power to the rise of the power supply voltage Vcc, must first be set. The transistor 192 is turned on by the base voltage applied through the resistor 194, and a current path from the resistor 158 to the reference potential via the emitter and the collector of the transistor 192 is formed. Due to the formation of this current path, the base voltage applied to the transistor 157 does not reach the predetermined base voltage value,
The transistor 157 is kept off. By turning off the transistor 157, the triac 151 is kept in the off state.

Next, when the power supply voltage Vcc rises and the base voltage applied via the Zener diode 195 reaches a predetermined base voltage value, for example, 0.7 V, for a time determined by the time constant of the resistor 196 and the capacitor 197, the transistor 197 turns on and the power supply voltage Vcc
, A current path reaching the reference potential through the resistor 194 and the emitter-collector of the transistor 193 is formed. Due to the formation of this current path, the base voltage applied to the transistor 192 becomes lower than the required base voltage value for turning on, and the transistor 192 turns off.

When the transistor 192 is turned off, the base voltage output from the hysteresis comparator 117 via the resistor 158 can be applied to the base of the transistor 157, and the hysteresis comparator 11
The transistor 157 is turned on / off by the base voltage from
The state can be turned off. That is, triac 15
1 can be turned on / off in accordance with the voltage of the input AC power.

As described above, since the start-up circuit 191 is configured to hold the triac 151 in the off state during the period from the input of the AC power to the rise of the power supply voltage Vcc, the triac 151 is turned on ( It is possible to prevent a voltage greater than necessary from being applied to the smoothing capacitors 103 and 104, the low-voltage power supply unit 105, and the like when 200-V AC power is input in a state where the voltage doubler rectification is set). In addition, it is possible to prevent the cost of the device from being increased by setting the smoothing capacitors 103 and 104, the low-voltage power supply unit 105, and the like to have a withstand voltage specification larger than necessary.

[0080]

As described above, according to the image forming apparatus of the first aspect, the detecting means for detecting the time when the absolute value of the input AC power becomes smaller than the predetermined value near zero, and the detecting means Determining means for determining the voltage value of the input AC power based on the result of the detection, and using the determination result of the determining means for the fixing control in the fixing means and the power supply control in the main power control means. It is possible to perform appropriate fixing control in the fixing unit and power supply control in the main power supply control unit according to the voltage of the AC power input as power.

According to the image forming apparatus of the present invention, the fixing control using the judgment result of the judging means sets a plurality of temperature control modes for fixing the developer image on the transfer material based on the judgment result of the judging means. It consists of control to switch selectively,
Since the power supply control using the determination result of the determination unit includes control for switching a plurality of power conversion modes for converting the input AC power to the driving power for each unit based on the determination result of the determination unit, the input AC power The temperature control mode and the power conversion mode appropriate for the voltage of the power supply can be selected and executed.

According to the image forming apparatus of the third aspect, a plurality of temperature control modes are used to control the power supply to the heater provided in the fixing means by turning on / off the input AC power. Therefore, it is possible to select an appropriate mode for controlling the power supply amount to the heater of the fixing unit in accordance with the voltage of the input AC power.

According to the image forming apparatus of the fourth aspect, the first temperature for controlling the power supply to the heater provided in the fixing means by turning on or off for each wave number of the input AC power. A control mode and a second temperature control mode for controlling a power supply amount to a heater provided in the fixing unit by changing a conduction angle of the input AC power are set, and based on a result of the determination by the determination unit. Since the power supply control means for selecting and executing one of the first temperature control mode and the second temperature control mode is provided, the AC power input from the first and second temperature control modes is provided. And selecting and executing an appropriate mode according to the voltage.

According to the image forming apparatus of the present invention, the plurality of power conversion modes include a first power conversion mode for converting input AC power into full-wave rectified power and then converting the input AC power into drive power for each unit. And a second power conversion mode in which the obtained AC power is double-voltage rectified and then converted into drive power for each unit. Therefore, according to the voltage of the AC power input from the first and second power conversion modes. An appropriate mode can be selected and executed.

According to the image forming apparatus of the present invention, the first rectifier for full-wave rectifying the input AC power, the second rectifier for rectifying the input AC power by double voltage,
A converter for converting power from one of the first rectifier and the second rectifier into drive power for each unit; a first power conversion mode and a second power conversion based on a determination result of the determiner; The conversion mode switching means for selectively switching either one of the first rectification means and the second rectification means so as to execute one of the modes is provided. It is possible to select and execute an appropriate mode according to the voltage of the input AC power from the second power conversion mode.

According to the image forming apparatus of the present invention, when AC power is input, the conversion mode switching means is set to select the first rectifying means. Voltage can be prevented from being applied to the circuit components constituting the first and second rectifiers, converters, and the like, and the withstand voltage specification is higher than necessary. It is possible to prevent the cost of the apparatus from increasing due to the use of circuit components.

According to the image forming apparatus of the present invention, the judging means includes a low-pass filter for averaging the detection result of the detecting means, and the detection result averaged by the low-pass filter and a predetermined value set in advance. , And a voltage value of the input AC power is determined based on the comparison result by the hysteresis comparator.

According to the power control method of the ninth aspect, the time when the absolute value of the input AC power becomes smaller than a predetermined value near zero is detected, and the voltage value of the input AC power is determined based on the detection result. Since the determination result is used for the fixing control in the fixing unit and the power supply control in the main power control unit, the fixing control in the fixing unit and the main power supply appropriate for the AC power input as the main power from a commercial power supply or the like are performed. The power supply control in the control means can be performed.

According to the power control method of the tenth aspect,
The fixing control using the determination result includes a control for selectively switching a plurality of temperature control modes for fixing the developer image to the transfer material based on the determination result, and the power supply control using the determination result includes the input AC power. From a plurality of power conversion modes for converting power to driving power for each means based on the determination result, so that an appropriate temperature control mode and power conversion mode corresponding to the input AC power voltage are selected and executed. can do.

According to the eleventh power control method,
Multiple temperature control modes turn on the input AC power,
Since the power supply to the heater provided in the fixing unit is controlled by turning off the power, the mode in which the power supply to the heater of the fixing unit is appropriately controlled according to the voltage of the input AC power. Can be selected.

According to the power control method of the twelfth aspect,
A first temperature control mode for controlling the amount of power supplied to a heater provided in the fixing unit by turning on or off for each wave number of the input AC power, and changing a conduction angle of the input AC power. A second temperature control mode for controlling the amount of electric power supplied to the heater provided in the fixing unit, and based on the determination result, one of the first temperature control mode and the second temperature control mode is set. Since either one is selected and executed, it is possible to select and execute an appropriate mode according to the voltage of the AC power input from the first and second temperature control modes.

According to the power control method of the thirteenth aspect,
A plurality of power conversion modes include a first power conversion mode in which input AC power is converted into drive power for each unit after full-wave rectification, and a drive power for each unit after input AC power is double-voltage rectified. And a second power conversion mode for performing the first power conversion mode and the second power conversion mode based on the determination result. It is possible to select and execute an appropriate mode according to the voltage of the input AC power from the power conversion modes.

According to the power control method of the fourteenth aspect,
At the time of inputting AC power, the input AC power is set to perform full-wave rectification.Therefore, a voltage larger than necessary with respect to the input AC power voltage is applied to circuit components by voltage doubler rectification. Therefore, the cost of the apparatus can be prevented from increasing due to the use of the circuit component having the withstand voltage specification more than necessary.

According to the power control method of claim 15,
The detection result is averaged by a low-pass filter, the detection result averaged by the hysteresis comparator is compared with a predetermined value, and a voltage value of the input AC power is determined based on the comparison result. Can be.

[Brief description of the drawings]

FIG. 1 is a diagram schematically showing a configuration of an image forming apparatus according to a first embodiment of the present invention.

FIG. 2 is a diagram showing a main power supply circuit configuration of main power control means in the laser beam printer of FIG.

FIG. 3 is a diagram showing a main power supply circuit configuration of main power control means in the laser beam printer of FIG. 1;

FIG. 4 is a diagram showing a rectified waveform of an AC power input to the laser beam printer of FIG. 1 and a waveform of a zero-cross signal.

FIG. 5 is a circuit diagram showing a configuration of a zero cross circuit of FIG. 3;

FIG. 6 is a diagram illustrating a main power supply circuit configuration of a main power control unit in a second embodiment of the image forming apparatus of the present invention.

FIG. 7 is a diagram illustrating a configuration of a main power supply circuit of a main power supply control unit according to a third embodiment of the image forming apparatus of the present invention.

FIG. 8 is a diagram illustrating a main power supply circuit configuration of a main power control unit according to a fourth embodiment of the image forming apparatus of the present invention.

9 is a circuit diagram showing a configuration of a start-up circuit in the main power supply circuit of FIG.

FIG. 10 is a diagram schematically showing a configuration of a conventional laser beam printer.

11 is a diagram showing a main power supply circuit configuration of main power control means in the laser beam printer of FIG.

FIG. 12 is a diagram showing a main power supply circuit configuration of main power control means in the laser beam printer of FIG.

13 is a diagram showing a rectifier diode and a circuit configuration around the rectifier diode in the main power supply circuit of FIG. 12;

FIG. 14 is a waveform and wave number control of input AC power,
It is a figure which shows the heater conduction waveform by each of phase control.

[Explanation of symbols]

 7 Laser Scanner Unit 8 Image Forming Unit 23 Main Motor 120 Fixing Unit 121 Ceramic Heater 122 Thermistor 130a, 130c Engine Controller 102, 110 Rectifier Diode 103, 104 Smoothing Capacitor 105 Low Voltage Power Supply Unit 111 Zero Cross Circuit 113, 137 Photocoupler 114, 139, 157, 184 Transistor 116, 181 LPF (low-pass filter) 117, 182 Hysteresis comparator 133, 151 Triac 157 Triac photocoupler 191 Start-up circuit 198 Diode

Claims (15)

[Claims] 1. A latent image forming means for forming a latent image corresponding to an input image on a latent image carrier, and visualizing the latent image formed on the latent image carrier as a developer image. Developing means, transfer means for transferring the developer image to a transfer material, fixing means for fixing the developer image to the transfer material, and conversion of AC power input from outside into drive power corresponding to each of the means. A main power supply control unit for performing power supply control for supplying the driving power to the respective units, wherein a time when the absolute value of the input AC power becomes smaller than a predetermined value near zero is detected. Detecting means, and determining means for determining a voltage value of the input AC power based on a detection result of the detecting means. Supply control An image forming apparatus characterized by being used for: 2. The fixing control using the determination result of the determination unit, wherein the plurality of temperature control modes for fixing the developer image on the transfer material are selectively switched based on the determination result of the determination unit. Wherein the power supply control using the determination result of the determination unit is configured to switch a plurality of power conversion modes for converting the input AC power into drive power for the respective units based on the determination result of the determination unit. 2. The method according to claim 1, wherein
The image forming apparatus as described in the above. 3. The plurality of temperature control modes are modes in which the input AC power is turned on and off to control a power supply amount to a heater provided in the fixing unit. The image forming apparatus according to claim 2. 4. A first temperature control mode for controlling an amount of electric power supplied to a heater provided in the fixing unit by turning on or off for each wave number of the input AC power, and A second temperature control mode for controlling a power supply amount to a heater provided in the fixing unit by changing a conduction angle of the AC power, and setting the first temperature based on a determination result of the determination unit. 4. The image forming apparatus according to claim 3, further comprising a power supply control unit that selects and executes one of the control mode and the second temperature control mode. 5. The plurality of power conversion modes include a first power conversion mode in which the input AC power is full-wave rectified and then converted into drive power for each of the units, and a doubling of the input AC power. 3. The image forming apparatus according to claim 2, further comprising a second power conversion mode in which voltage rectification is performed and then converted into drive power for each of the units. 6. A first rectifier for performing full-wave rectification on the input AC power, a second rectifier for performing voltage double rectification on the input AC power, the first rectifier and the second rectifier. A converter for converting power from one of the rectifiers into driving power for each of the first and second rectifiers; and a first power conversion mode and a second power conversion mode based on a determination result of the determination unit. And a conversion mode switching means for selectively switching one of the first rectification means and the second rectification means so as to execute one of the modes. The image forming apparatus according to claim 5. 7. An image forming apparatus according to claim 6, wherein said conversion mode switching means is set to select said first rectifying means when said AC power is input. 8. The low-pass filter for averaging the detection result of the detection unit, and a determination unit for comparing the detection result averaged by the low-pass filter with a predetermined value. 2. The image forming apparatus according to claim 1, further comprising a hysteresis comparator, wherein the voltage value of the input AC power is determined based on a comparison result by the hysteresis comparator. 9. A latent image forming means for forming a latent image corresponding to an input image on a latent image carrier, and visualizing the latent image formed on the latent image carrier as a developer image. Developing means, transfer means for transferring the developer image to a transfer material, fixing means for fixing the developer image to the transfer material, and conversion of AC power input from outside into drive power corresponding to each of the means. A power control method for controlling the power supply for supplying the driving power to the respective units, wherein the absolute value of the input AC power is higher than a predetermined value near zero. Detect the time when it gets smaller,
A power control method comprising: determining a voltage value of the input AC power based on the detection result; and using the determination result for fixing control in the fixing unit and power supply control in the main power control unit. 10. The fixing control using the determination result, the control comprising selectively switching a plurality of temperature control modes for fixing the developer image to the transfer material based on the determination result. 10. The power supply control according to claim 9, wherein the plurality of power conversion modes for converting the input AC power into drive power for the respective units are switched based on the determination result. Power control method. 11. The temperature control mode according to claim 1, wherein the input AC power is turned on and off to control a power supply amount to a heater provided in the fixing unit. The power control method according to claim 10, wherein 12. A first temperature control mode for controlling an amount of electric power supplied to a heater provided in the fixing unit by turning on or off for each wave number of the input AC power, and A second temperature control mode for controlling a power supply amount to a heater provided in the fixing unit by changing a conduction angle of the AC power is set, and the first temperature control mode and the second temperature control mode are set based on the determination result. 12. The power control method according to claim 11, wherein one of the second temperature control modes is selected and executed. 13. The plurality of power conversion modes include a first power conversion mode in which the input AC power is full-wave rectified and then converted into drive power for each of the units, and a double of the input AC power. A second power conversion mode in which voltage rectification is performed and then converted into drive power for each of the units, and one of the first power conversion mode and the second power conversion mode based on the determination result. The power control method according to claim 10, wherein the mode is executed. 14. The power control method according to claim 13, wherein when the AC power is input, the input AC power is set to perform full-wave rectification. 15. An average of the detection result by a low-pass filter, a comparison between the averaged detection result by a hysteresis comparator and a predetermined value, and a voltage of the input AC power based on the comparison result. The power control method according to claim 9, wherein a value is determined.