Image forming apparatus using press member to prevent deflection of belt

摘要

An outer roller is provided at a position offset upstream, in a rotation direction of an image carrying belt, of an inner roller. The inner and outer rollers are provided across the image carrying belt and form a transfer nip portion nipping and conveying a recording medium. A press member presses the image carrying belt from an inner circumferential side at upstream of the inner roller. The press member is provided such that a length along a belt surface of the image carrying belt between a downstream end of a part thereof in contact with the image carrying belt and an upstream end of the transfer nip portion is shorter than a length of an end margin formed on an upstream end area of the recording medium.

主权项

1. An image forming apparatus comprising:
an endless image carrying belt rotating while carrying a toner image on a surface thereof; an inner roller provided on an inner circumferential side of the image carrying belt and being in contact with the image carrying belt; an outer roller, provided on a side opposite from the inner roller across the image carrying belt, forming a transfer nip portion, with the inner roller, where a recording medium is nipped and conveyed; a power supply applying voltage between the inner and outer rollers to transfer the toner image from the image carrying belt to the recording medium conveyed through the transfer nip portion; and a press member provided upstream, with respect to a rotation direction of the image carrying belt, of the inner roller, and pressing the image carrying belt from the inner circumferential side of the image carrying belt at a position closer to the outer roller side than a first imaginary line, which is orthogonal to a second imaginary line connecting a center of rotation of the inner roller and a center of rotation of the outer roller, and passes through the transfer nip portion, the press member being configured such that a length along a surface of the image carrying belt between a downstream end of a part of the press member in contact with the image carrying belt and an upstream end of the transfer nip portion is shorter than a length of a rear end margin formed out of an image forming area and formed on an upstream end area of a surface of the recording medium with respect to a recording medium conveying direction.