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PRINCIPLES OF OPERATION
3. Printer Mechanism
3-1. Thermal Printhead
The TSP400 printers utilize thermal line printing. The thermal printhead consists of a horizontal line of 576 heat elements.
These elements print one line of dots at a time as the paper passes over the head. The printhead is fixed in position; only
the paper moves.
The printer prints a dot by heating the corresponding heat element. The heated element generates a chemical reaction in
the coloring layer of the thermal paper, resulting in the formation of a visible dot.
Fig. 2-16 Principle of Thermal Printing
3-2. Paper-Feed Mechanism
The paper-feed mechanism is comprised of paper-feed motor, gear train, platen, and thermal printhead. The paper-feed
motor drives the gear train, which in turn rotates the platen. The platen carries the thermal paper past the printhead.
The paper-feed motor is a PM (permanent magnet) type, 4-phase 48-pole step motor. 3 steps feed the paper approximately
0.125mm.
Fig. 2-17 Paper-Feed Machanism
Thermal head
Thermal paper
Printed point
Platen
Heat element
Coloring layer
Gear train
Paper-feed motor
Thermal head
Thermal paper
Platen