Print element arrangement in serial matrix printer

Abstract

A serial printer having a dot type printing head for printing on a paper. The printer includes 2N columns of dot forming elements where N is a positive integer equal to 2 or more and a carriage supported on the printer for reciprocal movement across the paper in a carriage direction. The columns of dot forming elements are supported on the carriage for selectively printing dots on a paper. Each column of the dot forming elements is spaced a predetermined distance from adjacent columns of the dot forming elements in the carriage direction. Each dot forming element column includes a plurality of dot forming elements arranged in a line and spaced apart from one another in the column direction by a dot pitch substantially equal to N. A drive system selectively drives selected dot forming elements in each column of dot forming elements by one of an even number timing and an odd number timing. Each column of dot forming elements driven by an even number timing is shifted in the column direction by one dot with respect to each other column of dot forming elements driven by an even number timing. Each column of dot forming elements driven by an odd number timing is shifted in a column direction by one dot with respect to each other column of dot forming elements driven by an odd number timing. Each column of dot forming elements driven by an even number timing is shifted in the column direction by less than about 1/3 dot pitch with respect to at least one column of dot forming elements driven by an even number timing.