Heating device and image forming apparatus
AssigneeKyocera Mita Corporation
InventorMasayuki Mochizuki
Life of this patent
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Abstract
A controller outputs a heater control signal in synchronization with a rise in a zero-cross signal. In response to the heater control signal, a switching device of a heater driving circuit switches ON/OFF. However, a noise occurs in an output voltage of an AC power source at the time of switching, and this noise causes a false zero-cross signal. For the purpose of preventing operation of a heater in accordance with the false zero-cross signal, the controller disregards the rise in the zero-cross signal during a set time period after the rise in the heater control signal.
Claims8
A heating device comprising:
- a heater which is driven by a power supplied from an AC power source;
- a switching portion which switches ON/OFF of the power supplied from the AC power source to the heater;
- a zero-cross signal output portion which outputs a zero-cross signal in response to a zero-cross point of an AC voltage outputted from the AC power source;
- and
- a controller which controls the switching portion to switch ON/OFF in response to the zero-cross signal, wherein
- the controller disregards the zero-cross signal outputted within a predetermined time period after controlling the switching portion to switch ON/OFF and prevents the switching portion from switching ON/OFF in response to the zero-cross signal.
An image forming apparatus comprising:
- an image forming section which forms an image on a recording medium;
- a heater which is driven by a power supplied from an AC power source;
- a fixing section which includes a heat roller, which uses a heat supplied from the heater to heat the recording medium on which the image is formed by the image forming section, and a pressure roller which is pressed against the heat roller, the fixing section fixing toner on the recording medium to the recording medium by sandwiching the recording sheet between the heat roller and the pressure roller;
- a switching portion which switches ON/OFF the power supplied from the AC power source to the heater;
- a zero-cross signal output portion which outputs a zero-cross signal in response to a zero-cross point of an AC voltage outputted from the AC power source;
- and
- a controller which controls the switching portion to switch ON/OFF in response to the zero-cross signal, the controller disregarding the zero-cross signal outputted within a predetermined time period after controlling the switching portion to switch ON/OFF and prevents the switching portion from switching ON/OFF in response to the zero-cross signal.
Dependencies are inferred from the claim text.