SHEET SUPPLY DEVICE AND IMAGE FORMING APPARATUS

A sheet supply device includes a supporter, a rotation device, a guide, a support shaft, a biasing member, a sensor, a roller, and control circuitry. The sensor is disposed to protrude from the facing portion toward the roll and biased in a direction to contact the outer peripheral surface of the roll. The sensor outputs a detection signal at a level corresponding to an amount at which the sensor protrudes from the facing portion. The roller is supported by the facing portion, to contact the outer peripheral surface of the roll at a position different from a position of the sensor in a circumferential direction of the roll. The control circuitry controls the rotation device based on a signal change rate that is a change amount of the level of the detection signal per unit time. The control circuitry causes the rotation device to rotate the spool in the winding direction, and stops an operation of the rotation device when the signal change rate based on a change in relative positions between the outer peripheral surface and the sensor without passage of a leading end of the sheet through the position of the sensor does not exceed a predetermined reverse set threshold value.