Patent ID: 8696104
Filing Date: 2014-04-15
Classification: G03G

Abstract:
1. A printer for the direct marking of document images on a substrate, the printer comprising: an imaging drum having a first longitudinal axis, and mounted for rotation around the first longitudinal axis, the imaging drum operative to receive a pattern of marking ink corresponding to an image to be printed on the substrate; a transfix roller having a second longitudinal axis and mounted for rotation around the second longitudinal axis, the transfix roller being selectively held against the imaging drum by a transfix force, the interface of the imaging drum and the transfix roller forming a transfix nip having a nip width, wherein an image is formed on the substrate passed through the transfix nip by the marking ink deposited on the imaging drum; a motor; a drive train operatively connecting the motor to the imaging drum; a motor drive unit controlling the speed and direction of the motor, to drive the imaging drum with a corresponding speed and direction; and a substrate sensor operative to detect the substrate entering into or exiting from the transfix nip, and to output a signal to the motor drive unit based upon the detection, wherein the motor drive unit varies the torque applied to the imaging drum in response to the signal from the substrate sensor, the variation in torque being sufficient to maintain a constant rotational speed of the imaging drum notwithstanding the substrate passing through the transfix nip.