Character printing device

A character printing device comprising a printing drum on the peripheral wall of which a plurality of character types are arranged in the axial direction (row) of the drum and in the circumferential direction (column) thereof;

• a printing information source for generating printing instruction signals for selectively printing any of said character types on the drum on a record medium;
• a first driving means for shifting the drum along the axis thereof in accordance with the printing instruction signals from the printing information source to position any character type column on the drum opposite a desired character printing position on the record medium;
• a second driving means for rotating the drum around the axis thereof in accordance with the printing instruction signals from the printing information source to position any character type row on the drum opposite the desired character printing position on the record medium;
• a hammer disposed close to the drum and opposed to an outer peripheral wall portion of the drum with the record medium interposed therebetween;
• a third driving means for shifting the hammer at least step by step in a direction parallel with the axis of the drum to determine a character printing position relative to the record medium;
• and a striking means for striking with the hammer said opposed peripheral wall portion of the drum through the record medium,
• the improvement wherein said first driving means comprises:
• a first memory means (81, 91, 187) coupled with said printing information source to store that coded signal of the printing instruction signals from said printing information source which represents a character type column containing the character type on said drum printed immediately before a character to be printed next;
• a character type column selection circuit means (83, 93, 189) coupled with said first memory means (81, 91, 187) and said printing information source to determine the direction and distance of the axial shift of said drum being moved to face the striking wall surface of said hammer by comparing coded signals stored in said first memory means (81, 91, 187) with printing instruction signals generated by said printing information source and representing a character type column containing that of the character types of said drum which is going to be printed next, thereby to provide an output corresponding to said determined direction and distance;
• and
• a shift control means (64, 98, 194) coupled with said character type column selection means (83, 93, 189) axially to shift said drum in accordance with the output from said character type column selection means (83, 93, 189).