Fixing device, image forming apparatus, and heating control method
A heating unit is heated by supply of an alternate-current power. A heating control unit executes a phase control to supply the alternate-current power to the heating unit for an ON-width in at least a half-wave period of the alternate-current power. A storing unit stores therein parameters for calculating the ON width. The heating control unit calculates the ON width based on the parameters stored in the storing unit and executes the phase control using a calculated ON width.
1. A fixing device comprising:
a heating unit that is heated by supply of an alternate-current power;
a heating control unit that executes a phase control to supply the alternate-current power to the heating unit for an ON-width in at least a half-wave period of the alternate-current power; and
a storing unit that stores therein parameters for calculating the ON width and a duty step that defines an amount of increase or decrease in the ON width, wherein
the heating control unit calculates the ON width based on the parameters and the duty step stored in the storing unit and executes the phase control using a calculated ON width, wherein
the heat control unit calculates the ON width based on the duty step that defines an amount of increase in the ON width in case of a soft-start period, and
the heat control unit calculates the ON width based on the duty step that defines an amount of decrease in the ON width in case of a soft-end period, wherein
the parameters include:
the duty step that defines an amount of increase in the ON width, and
a phase control period that defines a period during which the phase control is executed, and
the heating control unit calculates a number of half-wave periods for which the duty step is added based on the phase control period and the half-wave period, and calculates the ON width based on the calculated number of half-wave periods and the duty step.
2. The fixing device according to claim 1 , wherein
the parameters further include a last duty that defines a threshold of the ON width, and
when the calculated ON width exceeds the last duty, the heating control unit executes the phase control using the last duty.
3. The fixing device according to claim 1 , wherein the parameters further include a first duty that defines an ON width in a first half-wave period.
4. The fixing device according to claim 2 , wherein the parameters further include a first duty that defines an ON width in a first half-wave period.
5. An image forming apparatus comprising:
a fixing device for fixing a toner image on a recording medium, the fixing device including:
a heating unit that is heated by supply of an alternate-current power,
a heating control unit that executes a phase control to supply the alternate-current power to the heating unit for an ON-width in at least a half-wave period of the alternate-current power, and
a storing unit that stores parameters for calculating the ON width and a duty step that defines an amount of increase or decrease in the ON width, wherein
the parameters include:
the duty step that defines an amount of increase in the ON width, and
a phase control period that defines a period during which the phase control is executed,
the heating control unit calculates a number of half-wave periods for which the duty step is added based on the phase control period and the half-wave period, and calculates the ON width based on the calculated number of half-wave periods and the duty step
the heating control unit executes the phase control using the calculated ON width,
the heat control unit calculates the ON width based on the duty step that defines an amount of increase in the ON width in case of a soft-start period, and
the heat control unit calculates the ON width based on the duty step that defines an amount of decrease in the ON width in case of a soft-end period.
6. A heating control method performed in a fixing device, the heating control method comprising:
heating a heating unit by supplying an alternate-current power;
executing, by a heat control unit, a phase control to supply the alternate-current power to the heating unit for an ON-width in at least a half-wave period of the alternate-current power
storing parameters for calculating the ON width and a duty step that defines an amount of increase or decrease in the ON width
wherein
the parameters include:
the duty step that defines an amount of increase in the ON width, and
a phase control period that defines a period during which the phase control is executed, and
the executing includes:
calculating a number of half-wave periods for which the duty step is added based on the phase control period and the half-wave period,
calculating the ON width based on the calculated number of half-wave periods and the duty step, and
executing the phase control using a calculated ON width, wherein
the heat control unit calculates the ON width based on the duty step that defines an amount of increase in the ON width in case of a soft-start period, and
the heat control unit calculates the ON width based on the duty step that defines an amount of decrease in the ON width in case of a soft-end period.