Printer having print head position sensor and mechanism for inhibiting print head movement when ribbon holder is not in initial position

摘要

A printer wherein a zero position sensor generates a zero- position signal and a non-zero-position signal depending upon whether the print head is placed in its zero position or not, and a print head locking mechanism is provided for permitting print head movement from the zero position when a ribbon holder supporting one or more ribbons is placed in a predetermined initial position, and inhibiting the print head movement from the zero position when the ribbon holder is not in the initial position, so that the non-zero-position signal is generated if the print head is moved away from the zero position with the ribbon holder placed in the initial position. When the ribbon holder is not in the initial position, the print head is not moved away from the zero position and the zero-position signal remains even if the print head is commanded to move away from the zero position, so that the single zero position sensor cooperates with the locking mechanism to detect both the print head zero position and the ribbon holder initial position.