Abstract: A print head carriage of an impact printer is monitored by means of a segmented timing member which is separate from but coupled to and movable in coordination with the carriage. The segmented timing member is associated with a carriage drive motor and preferably comprises a toothed wheel which is rotated by a motor drive gear also used to move the print head carriage. The teeth of the toothed wheel are monitored by an optical sensor with a resulting series of pulses being accumulated to define the rotation of the toothed wheel and thereby the movement and position of the print head carriage. A home carriage position is directly indicated via a carriage position indicating member which is operated by the print head carriage to interrupt the optical sensor of the preferred embodiment.