Page: 27Service Guide ML390/391Chapter 2 Principles of Operation2.4.02 Space Mechanism / OperationThe spacing operation is performed by applying power to the DC spacing motor. This drives the carriageframe along the carriage shaft, space rack, and guide rail. The carriage shaft, space rack, and guide railare parallel to the platen.The spacing motor assembly consists of the following items.· DC Motor / Gear· Carriage Frame· Carriage Shaft· Space Rack· Encoder Disk Sensor· Encoder Disk· Guide RailSpacing OperationThe printhead and spacing motor are mounted on the carriage frame. The carriage frame moves along thecarriage shaft, space rack, and guide rail. The carriage shaft, space rack, and guide rail are parallel to theplaten. As the spacing motor rotates counterclockwise, the carriage frame is driven to the right.When the spacing motor rotates one turn, the carriage frame moves 0.8 inch (20.32 mm).Motor rotation turns the encoder disk. The timing windows on the disk then pass through the encoder disksensor. The position of the carriage frame is obtained by counting the pulses generated by the encoderdisk sensor as the disk turns.
