Image forming apparatus

摘要

An image forming apparatus includes an image bearing member, a voltage source, a fixing device including a rotatable member, an executing portion for executing an operation in a both side mode, and a setting portion. The setting portion sets a transfer voltage in the operation for a second surface so that an absolute value of the transfer voltage when a recording material region, which starts from a most downstream end position and which passed through a fixing portion through a first one full circumference of the rotatable member when the toner image is fixed on a first surface passes through the transfer portion, is greater than an absolute value of the transfer voltage when a recording material region passed through the fixing portion through a second one full circumference of the rotatable member when the toner image is fixed on the first surface passes through the transfer portion.

主权项

1. An image forming apparatus comprising:
an image bearing member for bearing a toner-image; a voltage source for applying a transfer voltage to a transfer portion where the toner image is transferred from said image bearing member onto a recording material; a fixing device, including a rotatable member to be heated, for fixing the toner image on the recording material by heating the recording material, on which the toner image is transferred, at a fixing portion while causing the recording material to contact the rotatable member; an executing portion for executing an operation in a both-side mode in which the recording material, on which the toner image is transferred and fixed on a first surface thereof, is fed to the transfer portion, to which the transfer voltage is applied, where the toner image is transferred onto a second surface of the recording material and then is fixed on the second surface of the recording material by said fixing device to form both-side images; and a setting portion for setting the transfer voltage when the toner image is transferred onto the second surface of the recording material, wherein said setting portion sets the transfer voltage in the operation for the second surface in the both-side mode so that an absolute value of the transfer voltage when a recording material region, which starts from a downstreammost end position with respect to a recording material feeding direction and which passed through the fixing portion through a first one full circumference of the rotatable member when the toner image is fixed on the first surface, passes through the transfer portion is greater than an absolute value of the transfer voltage when a recording material region passed through the fixing portion through a second one full circumference of the rotatable member when the toner image is fixed on the first surface passes through the transfer portion.