System for controlling printers having differing dot densities

Abstract

A font converting device converts (dot density conversion) a down-line load font received through an interface device into a font represented by a dot matrix of the same size as that of a resident font stored in first memory and stores the converted down-line load font in a second memory. A control circuit selectively reads the fonts of the first memory (resident font) or the fonts of the second memory (converted down-line load font) in conformity to a font code included in print data, edits dot image data, and then provides the same to a printing unit to be controlled, namely, a printer in a narrow sense. Only the rarely used down-line load font is subjected to dot density conversion so that the print dot density of the converted down-line load font coincides with that of the print dot density of the printer to be controlled, while a frequently used font of a print dot density coinciding with that of the printer is stored as resident font. Thus, a plurality of printers differing from each other in print dot density can be connected to the host unit of a system in the same interface conditions without entailing the variation of character pattern and the size of print area.