Patent ID: 8891988

Claim:
An image forming apparatus comprising a recording paper conveying portion for conveying a recording paper, an image forming portion for performing image formation on the recording paper conveyed by the recording paper conveying portion, and a control portion for controlling the recording paper conveying portion and the image forming portion, wherein the image forming portion has a transfer portion for transferring a toner image formed on an image carrier onto the recording paper, and a fixing portion for heating and compressing the recording paper on which the toner is transferred to fix the toner image to the recording paper, the recording paper conveying portion has a conveyance path for conveying the recording paper heated and compressed by the fixing portion to the transfer portion again, the control portion controls to heat and compress the recording paper by the fixing portion without performing transfer of the toner image by the transfer portion under a predetermined condition, and is configured to set variably the number of times to pass through the fixing portion without performing transfer of the toner image to the recording paper and pressure force of the fixing portion when the recording paper passes through the fixing portion, the control portion conveys the recording paper heated and compressed by the fixing portion without performing transfer of the toner image by the transfer portion to the transfer portion again under the predetermined condition, and when the number of times to pass the recording paper through the fixing portion without performing transfer of the toner image by the transfer portion is set to be an odd number of times, the control portion gives an alarm that a front side and a back side of the recording paper are inverted due to setting of the odd number of times.