Method of determining print starting positions for an impact type dot printer

A method of determining print starting positions for an impact type dot printer including a rotatable platen having a plurality of axial projections and a printing head movable from a home position in spacing increments along the platen and having a print hammer actuatable to hit the projections one at a time to print dot-matrix characters on a recording medium between the platen and the print hammer, said method comprising the steps of:

• generating a print timing signal in synchronism with rotation of the platen, said print timing signal being indicative of positions in which the print hammer strikes the projections and being composed of a pulse-free blank and a plurality of subsequent pulses defining one cycle;
• moving the printing head from the home position for pre-spacing prior to a normal printing operation;
• generating a home signal when the printing head leaves the home position;
• counting the number of pulses of said print timing signal until a first pulse-free blank arrives while the printing head is moving for pre-spacing;
• storing data on a phase relationship between said print timing signal and said home signal based on the counted number of pulses;
• counting the number of pulses of said print timing signal generated after the printing head has left the home position until the first pulse-free blank arrives each time the printing head is moved in spacing increments for the normal printing operation;
• and
• setting print starting positions based on said stored data and said last-mentioned number of pulses as counted.