Grey-level drive circuit for LED print head in electrophotographic printer - has mode decoder for generating trigger signals in response to count values of clock pulses, and driver for producing strobe signals in response to logical combination of trigger and pulse signals

摘要

An LED print head (20) is controlled by a printer control circuit (22) that provides a horizontal synchronising signal (HSYNC) and clock pulses (LT) to a level decoder (28). A strobe pulse generator (30) provides pulses (T0-T2) to a drive circuit (32) that also receives a number of switching signals (M1-M3). The level decoder has a counter (31) as a buffer memory for the incoming pulses (LT). The outputs are decoded (34) to provide the switching signals (M1-M3) that determine the data groups provided for the print head. ADVANTAGE - Provides multiple grey levels for laser printer.