PURPOSE: To obtain the titled controlling system for printers, which is capable of reducing memory cost and also of simplifying control procedure and control circuit, by using a system in which printing positions are stored in a format register in order to control the amount of back space.

CONSTITUTION: Letters (i) and (w) are printed with widths li, lw at a proportional space, and "1" bit is set in the bit position corresponding to the printing position of the letter (i) in a format register. The "1" bit is set in the bit position 52 corresponding to the printing position of the letter (w). At the time of back spacing operation, the format register is searched in the opposite direction, and the amount of back spacing is controlled so that back spacing is made in the printing position in the vertical direction corresponding to the bit position at which "1" bit is set.