SERIAL DOT PRINTER

PURPOSE:To prevent a specified printing element in a printing head from being consumed and prevent printing quality from being lowered, by a method wherein the pitch in line shifting for printing rule lines in a printer is sequentially changed so that the position of a dot used for printing the rule lines is not fixed. CONSTITUTION:When a rule line printing code is detected by a code-analyzing part 1, a printing position for the scale line is determined by a rule line printing position setting part 2, and a wire dot controling part 4 is started. The controlling part 4 starts a line shift controlling part 3 so that a wire dot for printing the rule line is brought into a rule line printing position. The wire dot controlling part 4 so controls that the line shifting pitch is sequentially changed relatively to a character printing position by a one-dot amount each time a rule line is printed, and correspondingly, the wire dot used for printing the rule line is also sequentially changed over to the lower adjacent one.