Heater control device using phase angle control
First Claim
1. A heater control device for controlling a heater based on phase angle control, comprising:
- a heater control circuit comprising a series circuit of a first phase control switch and a reactor and a second phase control switch connected in parallel with the series circuit, the heater control circuit being connected in series with a heater;
a detecting means for detecting the zero-cross points in the waveform of an a.c. input voltage supplied to the heater; and
a phase angle control means, which based on the detection output of the zero-cross points from a detecting means, gradually alters a phase angle of current flow from the minimum range to the maximum range,characterized in that the phase angle control means performs control in such a manner that only the first phase control switch is turned on until the phase angle of the current flow reaches 180° and
then only the second phase control switch is turned on after the phase angle of the current flow has reached 180°
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1 Assignment
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Accused Products
Abstract
The control circuit includes: a series circuit of a first triac and a reactor; and a second triac in parallel with this series circuit so as to perform control of activation of a fixing heater. Since the fixing heater has a low resistance when the power switch is first turned on, the first triac is operated to perform phase angle control of current flow, and when the phase angle has become approximately equal to 180°, the first triac is stopped, at the same time the second triac starts to be operated. The switching from the first triac to the second triac is made quickly so that it is possible to reduce the power consumption from the reactor.
35 Citations
19 Claims
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1. A heater control device for controlling a heater based on phase angle control, comprising:
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a heater control circuit comprising a series circuit of a first phase control switch and a reactor and a second phase control switch connected in parallel with the series circuit, the heater control circuit being connected in series with a heater; a detecting means for detecting the zero-cross points in the waveform of an a.c. input voltage supplied to the heater; and a phase angle control means, which based on the detection output of the zero-cross points from a detecting means, gradually alters a phase angle of current flow from the minimum range to the maximum range, characterized in that the phase angle control means performs control in such a manner that only the first phase control switch is turned on until the phase angle of the current flow reaches 180° and
then only the second phase control switch is turned on after the phase angle of the current flow has reached 180°
. - View Dependent Claims (2, 3, 6, 7, 9)
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4. A heater control device for controlling a heater based on phase angle control, comprising:
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a heater control circuit comprising a series circuit of a first phase control switch and a reactor and a second phase control switch which shares in part a winding of the reactor and is connected in parallel with the series circuit, the heater control circuit being connected in series with a heater; a detecting means for detecting the zero-cross points in the waveform of an a.c. input voltage supplied to the heater; and a phase angle control means, which based on the detection output of the zero-cross points from the detecting means, gradually alters the phase angle of current flow from a minimum range to a maximum range, characterized in that the phase angle control means performs control in such a manner that only the first phase control switch is turned on until the phase angle of the current flow reaches 180° and
then only the second phase control switch is turned on after the phase angle of the current flow has reached 180°
. - View Dependent Claims (5)
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8. A heater control device for controlling a heater based on phase angle control, comprising:
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a heater control circuit comprising of a series circuit of a reactor, a first phase control switch and a resistor and a second phase control switch in parallel with the series circuit, the heater control circuit being connected in series with a heater; a detecting means for detecting the zero-cross points in the waveform of an a.c. input voltage supplied to the heater; and a phase angle control means, which based on the detection output of the zero-cross points from the detecting means, gradually alters the phase angle of current flow from the minimum range to a maximum range, characterized in that the phase angle control means performs control in such a manner that only the first phase control switch is turned on until the phase angle of the current flow reaches 180° and
then only the second phase control switch is turned on after the phase angle of the current flow has reached 180°
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10. A heater control device for controlling a heater based on phase angle control, comprising:
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a first heater control circuit comprising a first series circuit of a first phase control switch and a reactor and a second phase control switch connected in parallel with the first series circuit, the first heater control circuit being connected in series with a first heater; a first detecting means for detecting the zero-cross points in the waveform of an a.c. input voltage supplied to the first heater; a phase angle control means, which based on the detection output of the zero-cross points from the first detecting means, gradually alters the phase angle of the current flowing through the first phase control switch, from a minimum range to a maximum range, wherein the phase angle control means performs control in such a manner that only the first phase control switch is turned on until the phase angle of the current flow reaches 180° and
then only the second phase control switch is turned on after the phase angle of the current flow has reached 180°
;a second heater control circuit comprising a second series circuit of a third phase control switch and a reactor and a fourth phase control switch connected in parallel with the second series circuit, the second heater control circuit being connected in series with a second heater; a second detecting means for detecting the zero-cross points in the waveform of an a.c. input voltage supplied to the second heater; and a phase angle control means, which based on the detection output of the zero-cross points from the second detecting means, gradually alters the phase angle of the current flowing through the third phase control switch, from a minimum range to a maximum range, wherein the phase angle control means performs control in such a manner that only the third phase control switch is turned on until the phase angle of the current flow reaches 180° and
then only the fourth phase control switch is turned on after the phase angle of the current flow has reached 180°
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11. A heater control device for controlling a heater supplied with an a.c. input voltage, said heater control device comprising:
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a heater control circuit comprising a series circuit including a first phase control switch and a reactor, and a second phase control switch connected in parallel with the series circuit; a detecting circuit configured to detect zero-cross points in the waveform of the a.c. input voltage supplied to said heater; and a phase angle control circuit configured to control a phase of current to said heater based on detections of zero-cross points by said detecting circuit, wherein said phase angle control circuit controls the phase of the current to said heater by turning on only said first phase control switch until the phase of the current reaches 180°
, turning off said first phase control switch when the phase of the current reaches 180°
, and then turning on only said second phase control switch after the phase of the current reaches 180°
. - View Dependent Claims (12, 13, 14, 15, 16, 17)
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18. A heater control device for controlling a heater supplied with an a.c. input voltage, said heater control device comprising:
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a heater control circuit comprising a series circuit including a first phase control switch and a reactor, and a second phase control switch connected in parallel with a series connection of said first phase control switch and a part of said reactor; a detecting circuit configured to detect zero-cross points in the waveform of the a.c. input voltage supplied to said heater; and a phase angle control circuit configured to control the phase of the current to said heater based on detections of zero-cross points by said detecting circuit, wherein said phase angle control circuit controls the phase of the current to said heater by turning on only said first phase control switch until the phase of the current reaches 180°
, turning off said first phase control switch when the phase of the current reaches 180° and
then turning on only said second phase control switch after the phase angle of the current flow has reached 180°
. - View Dependent Claims (19)
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Specification