JPS6482074A - Image forming device having automatic switching function for transfer speed - Google Patents

Abstract

PURPOSE:To eliminate the need of labor required for switching speed, and to prevent a jam and a transfer failure to be caused by forgetting to input by detecting the length of a transfer material by a transfer material detecting sensor, and switching a transfer speed automatically in accordance with its length. CONSTITUTION:A form passes through carrying rollers 52, 53 from a feed paper cassette 5, abuts on a resist roller 54 and stops. When form sensors 56, 57 detect simultaneously even for an instant the form which is being carried, a CPU discriminates that its length is longer than a distance l between a transfer part A and a fixing part B, and discriminates that its length is shorter than l, when said detection is not executed. The roller 54 rotates at the timing at which the tip position of a toner image coincides with the tip of the form, and feeds the form to the transfer part. Also, the transfer speed is controlled in accordance with the length of the form which is detected. In such a way, since the transfer speed is set automatically, the operation is simplified, and a jam and a transfer failure to be caused by forgetting to input are prevented.