Paper Pick-Up - Digital Equipment COLORWRITER LSR 2000 Service Manual

Colorwriter LSR 2000 Printer
Service Guide
3-76
3: Operation

Paper pick-up

Cassette feeding
The presence of paper in the cassette is detected by the cassette
paper sensor (PS301).
When the print sequence command is received, the mechanical
controller drives the fixing unit motor (M2), then after 0.2 seconds,
drives the drum motor (M4) and the pick-up motor (M1).
Simultaneously, the pick-up solenoid (SL1) is turned on and the
drive of the pick-up motor is transferred to the pick-up roller, feed
rollers, and separation roller. After any multi-feed of the paper
picked up by the pick-up roller has been eliminated by the
separation roller, the paper is fed into the printer by feed rollers 1
and 2.
After passing through the registration paper sensor (PS302), the
paper reaches the registration roller. The registration roller is not
rotating at this time, so the paper temporarily stops in the
registration roller position. Its leading edge is curled and any skew is
corrected. A certain time period elapses after the paper has passed
through PS302, the registration roller clutch (CL3) is turned ON to
resume feeding the paper. When the paper reaches the paper top
sensor (PS303), the pick-up motor stops, stopping the paper.
The DC controller and the mechanical controller detect the
registration position of the transfer drum with the transfer drum top
sensor (PS8). Subsequently, this timing is used as reference for
executing the print sequence. The mechanical controller starts
driving the pick-up motor at a certain time after detecting the
registration position of the transfer drum. Therefore, the
temporarily stopped paper resumes being fed so that its leading edge
will match the gripper on the transfer drum and the leading edge of
the image on the photosensitive drum.