Epson LQ 1050 Technical Manual - Page 107

REV.-A Drive Transistor Short-circuit Check During printing, the CPU continuously checks the printhead drive transistors (Q! to Q9) for short circuits. The short-circuit check is performed between drive cycles. If any of the drive transistors are shorted, a LOW signal is input to AN2 of the CPU. Upon receiving this signal, the CPU stops printing, shuts off the +24 V drive voltage, and rings the buzzer. (See Figure 2-50.) Bi-directional Printing Alignment For bi-directional printing, printing position alignment is performed. The print timing pulse is delayed when the printhead moves from right to left, to align the vertical printing positions printed when the printhead moves from left tot right with those printed right to left. If a misalignment occurs, it can be adjusted using the control panel (Seee Section 4.3.3.). 2-63