Sheet position control for printer

摘要

The printer has a mechanical sensor (5) to monitor the leading edge of the sheet. From the initial position of the sheet the drive is reversed for a set distance and returned to the ready position. This is eg. used for an endless sheet feed where the printed page is moved out of the machine for tear off after which the remainder of the sheet feed is reset into the ready position. A sheet tension control is applied to smooth the sheet before the next print. The drive sequence for the sheet feed and the tension control remove any bends in the paper which would not easily be monitored by the sensor. This ensures a correct alignment for the next print. The tension control has two pressure rollers near the output slot of the printer, to tension the paper as it is returned to the ready position.