Patent ID: 9057996
Filing Date: 2015-06-16
Classification: G03G

Abstract:
1. A method for controlling a power supply for transfer in an image forming device comprising: an image carrier which is rotatable and capable of forming a toner image on a circumferential surface thereof, and is capable of rotating while holding the toner image thereon, a transfer member which is for transferring the toner image on the image carrier onto a recording paper sheet and capable of rotating, provided in a manner capable of pressing against, coming into contact with and retreating from the image carrier, and which forms a pressing nip by being pressed against the image carrier, the power supply for transfer which is for applying a voltage to the transfer member for transfer for transferring the toner image on the image carrier onto the recording paper sheet, and a recording paper sheet feed device for feeding the recording paper sheet into the pressing nip, the power supply for transfer being turned on by a power supply ON instruction signal, being turned off by a power supply OFF instruction signal, and using a voltage set by an output voltage setting signal as an output voltage when the power supply is on, the method comprising the steps of: turning on the power supply for transfer and setting the output voltage of the power supply for transfer to effectively 0 V before the transfer member is pressed against the image carrier, and switching the output voltage of the power supply for transfer from effectively 0 V to a high voltage for transfer after the transfer member is pressed against the image carrier, wherein the power supply for transfer comprises a first high voltage generating part which generates a voltage of a first polarity and a second high voltage generating part which generates a high voltage of a second polarity which is different from the first polarity, and both the first high voltage generating part and the second high voltage generating part simultaneously generate the high voltage when the power supply controller turns on the power supply for transfer and sets the output voltage of the power supply for transfer to effectively 0 V.