Epson SQ-B50/2550 Technical Manual page 120

REV.-A
2.4.2.6 Print Timing Signal Generation
The encoder signal also serves the PTS (print timing signal) generation in the DCU. PTS is a print timing
signal that works the printer head. The DCU determines the proper pulse cycles for a variety of printing
densities which have specific values for each printing mode. The calculated pulse cycle goes to the
PHC (Print Head Controller:68) gate array. Figure 2-56 shows the operational wave form. The PTS, the
wave form shown on the lower side, changes its cycles for the required printing mode (velocity and
print density). PTS alteration is conducted by a command execution to the DCU.
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Upper wave: Encoder pulse (ENA)
Lower wave: PTS signal
Figure 2-57. PTS Signal Wave Form
2-52