Logic circuit for grey-tone printer

摘要

Method and apparatus for producing a grey-tone image having areas of different average density values which are given by an n-digit binary number, all the bits of the binary number being interrogated in parallel by clock patterns. For the area to be printed an elemental area containing 2n pulses is selected which is printed in a total cycle of 2n <-> 1 clock pulses of the clock pattern. In this total cycle, at each clock pulse the drive of each pair of dots is determined in a manner such that the most-significant bit of the binary number is always used for driving while the remaining bits are used a number of times which depends upon their positional values. For this purpose, for each position of the binary number the clock pattern has a number of clock pulses which corresponds to the value of this position. The clock pulses for the individual positions are non-uniformly distributed in time, however, no clock pulses for the second and any further positions of the binary number coincide in time. Before each new print line the pattern will if required be shifted by additional clock pulses.