Method and apparatus for controlling operation of a printer

摘要

A printer for use in exposing a photosensitive material and method of operation thereof. The printer includes a rotatable polygon mirror having a plurality of adjacent facets. The mirror includes a reference facet and signal generator for generating a polygon index signal which defines a reference position. A light source for directing a light beam is provided for reflection of the beam off each of the adjacent facets for exposing the photosensitive material and defining a writing path. A sensor is also provided for generating a line start signal for each of the facets in response to the light beam passing over the sensor. The printer is provided with a switch for placing printer in a first set-up mode or writing mode. When in set-up mode a counter measures a first time period TS from the polygon index signal to a first line start signal generated by the reference facet. A counter also measuring a second time period TLS from a line start signal to the next line start signal generated from the next adjacent facet of the rotatable polygon mirror. A first facet synch signal TRI is determined using the first time period TS from said reference facet. TRI and TLS are stored in memory. The printer turns on and off the light source in a controlled manner from the information obtained during the set-up mode.