Paul S Ramsden, 81Cape Coral, FL

3970183, Jul 20, 1976

Jun 5, 1974

5/476581

Prentice Robinson - Pelham NH
Paul S. Ramsden - Hudson NH

Centronics Data Computer Corporation - Hudson NH

B41J 304

197 1R

An impact printer of the dot matrix type capable of printing in either the forward or reverse direction. Means are provided for determining the position of the print head at any given instant. Upon completion of a line of print the print head is abruptly halted. The next line of characters is examined to determine the end points of its character field. Comparisons are made to determine whether the print head lies within or beyond the end points. In cases where the print head lies beyond the end points of the character field, the printing occurs by moving the head in a direction toward the closest end point and then printing. If the print head occupies the location between the end points the position of the head is loaded into a pair of counters which are simultaneously counted up and down respectively. The outputs of the counters are continuously compared against the values representing the end point locations whereupon the first favorable comparison determines the shortest distance of print head travel for starting printing. High speed electronic circuitry is provided for storing data representing the next line to be printed in both forward and reverse formats whereupon the decision as to the direction in which data is printed automatically controls the appropriate storage medium.