Image formation apparatus and heater control method
AssigneeRicoh Company, Ltd.
InventorNaoki Satoh
Life of this patent
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Abstract
An image formation apparatus includes a fixing heater, and a zero-cross detector that detects zero-cross points of a frequency of an alternating current (AC) power supply connected to the heater. The image formation apparatus also includes a controller that controls light-on of the heater by pulse-width-modulation (PWM)-controlling the frequency of the AC power supply, that controls a duty width of a PWM control signal for the frequency of the AC power supply for a half period that corresponds to a period between the adjacent zero-cross points detected by the zero-cross detector, and that controls an amplitude of an input current from the AC power supply so that a waveform of the input current becomes a rough approximation of a sine wave.
Claims12
An image formation apparatus comprising:
- a heater used in a fixing device;
- a detection unit that detects zero-cross points of a frequency of an alternating current (AC) power supply connected to the heater;
- and
- a control unit that controls light-on of the heater by pulse-width-modulation (PWM)-controlling the frequency of the AC power supply, controls a duty width of a PWM control signal for the frequency of the AC power supply for a half period that corresponds to a period between the zero-cross points adjacent to each other detected by the detection unit, and controls an amplitude of an input current from the AC power supply so that a waveform of the input current becomes a rough approximation of a sine wave.
A heater control method comprising the steps of:
- detecting zero-cross points of a frequency of an alternating current (AC) power supply connected to a heater used in a fixing device;
- and
- controlling light-on of the heater by pulse-width-modulation (PWM)-controlling the frequency of the AC power supply, controlling a duty width of a PWM control signal for the frequency of the AC power supply for a half period that corresponds to a period between the zero-cross points adjacent to each other detected at the step of detecting, and controlling an amplitude of an input current from the AC power supply so that a waveform of the input current becomes a rough approximation of a sine wave.
Dependencies are inferred from the claim text.