Abstract: An image forming apparatus of the invention includes, in the image forming apparatus having a normal operation mode and plural power saving modes, a control unit to decide between the normal operation mode and the plural power saving modes, and plural switching power sources that can independently change switching frequencies according to the power saving mode instructed from the control unit.

Abstract: A center thermostat (16) corresponding to a center heater in a heat roller (10) and a side thermostat (17) corresponding to a side heater in the heat roller (10) are so installed that the distances to the center heater (11) and side heater (12) are equal in the diameter direction of the heat roller (10).

Abstract: A center thermostat (16) corresponding to a center heater in a heat roller (10) and a side thermostat (17) corresponding to a side heater in the heat roller (10) are so installed that the distances to the center heater (11) and side heater (12) are equal in the diameter direction of the heat roller (10).

Abstract: Return roller and carry roller are rotated by one drive source. To the carry roller which nips and holds paper when the paper is held, a driving force of the drive source is transmitted by a clutch only when the return roller carries out the paper toward a return direction. There is controlled paper carry by repeating a step of feeding an n-th sheet of paper on which the image formation on one side is completed to an image formation section, and feeding an n+1-th sheet of paper to a paper side reversal section, and a step of, under the state where the n+1-th sheet of paper is held at the paper side reversal section, ejecting the n-th sheet of paper on which the image formation on both sides is completed, and feeding an n+2-th sheet of paper to the return section.

Abstract: Return roller and carry roller are rotated by one drive source. To the carry roller which nips and holds paper when the paper is held, a driving force of the drive source is transmitted by a clutch only when the return roller carries out the paper toward a return direction. There is controlled paper carry by repeating a step of feeding an n-th sheet of paper on which the image formation on one side is completed to an image formation section, and feeding an n+l-th sheet of paper to a paper side reversal section, and a step of, under the state where the n+1-th sheet of paper is held at the paper side reversal section, ejecting the n-th sheet of paper on which the image formation on both sides is completed, and feeding an n+2-th sheet of paper to the return section.

Abstract: An image forming apparatus includes a constant-current power supply to supply operation currents to a charging unit and a removing unit, and keep the total of the operation currents at a predetermined value; and a correction circuit to detect a fluctuation in the operation current of the removing unit, and correct the predetermined value of the constant-current power supply circuit according to the detection results.