Abstract: An opaque flag mounted upon a printer carriage assembly interrupts the light emmitted by a LED from reaching a phototransistor when at the left-hand margin of the paper document. The carriage starts to move and when it reaches constant print velocity, the opaque flag moves away from the LED and the phototransistor to activate the phototransistor to trigger a gated oscillator to generate pulses of very uniform size and shape and preferably of a 50% duty cycle. The leading and trailing edges of the pulses from the gated oscillator generate strobe and delay strobe pulses of shorter pulse duration which, in turn, energize the wire actuating solenoids forming full-step and half-step dots the full-step dots creating characters within a 5 .times. 7 dot matrix and both the half-stepand full-step dots being forming characters within a 9 .times. 7 dot matrix.When printing is completed, a PRIME signal resets and abruptly stops the gated oscillator.

Abstract: A printer of the dot matrix type for printing, single, double and triple sized characters. Normal sized characters are printed in the conventional fashion. Double and triple sized characters are printed through a segmented technique in which segments of the double and triple sized characters are stored within readable memories (ROMS). For double sized characters which occupy two adjacent character lines, the segmented patterns for the upper portions of the characters are printed along the first normal sized character line. The lower half of the double sized characters is printed on the next adjacent character line by selection of the appropriate segmented patterns. Triple sized characters are printed in a similar manner, utilizing three lines of conventional sized characters. The same technique may be employed to create other graphic patterns of 1 to N lines, where N is a real integer equal to or greater than 2. The technique permits the utilization of either unidirectional or bidirectional printers.