Image forming apparatus that fixes toner image to recording medium using heater
AssigneeCanon Kabushiki Kaisha
InventorHiroshi Oguri
Life of this patent
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Abstract
In a caser where a first current is supplied to a first heater, a controller gradually increases the first current in a first period, supplies the first current based on a first duty cycle in a second period, and gradually reduces the first current to stop supplying the first current in a third period. In a case where a second current is supplied to a second heater, the controller gradually increases the second current in a fourth period, supply the second current based on a second duty cycle in a fifth period, and gradually reduces the second current to stop supplying the second current in a sixth period. The controller controls the supply of the second current such that part of the fourth period overlaps with the third period.
Claims9
An image forming apparatus comprising:
- an image forming unit configured to form an image on a sheet;
- a fixing unit configured to fix the image to the sheet, the fixing unit including:
- a first heater to which is supplied current for generating heat;
- and
- a second heater to which is supplied current for generating heat;
- a temperature sensor configured to detect a temperature of the fixing unit;
- and
- a controller configured to:
- control a first current supplied to the first heater and a second current supplied to the second heater such that the temperature detected by the temperature sensor maintains a target temperature;
- in a case where the first current is supplied to the first heater, gradually increase the first current in a first period, supply the first current based on a first duty cycle in a second period that follows the first period, and gradually reduce the first current to stop supplying the first current in a third period that follows the second period;
- in a case where the second current is supplied to the second heater, gradually increase the second current in a fourth period, supply the second current based on a second duty cycle in a fifth period that follows the fourth period, and gradually reduce the second current to stop supplying the second current in a sixth period that follows the fifth period;
- and
- control the supply of the second current such that part of the fourth period overlaps with the third period.
Dependencies are inferred from the claim text.