Bidirectional Print Position Adjustment; Overview Of Bidirectional Print Position Adjustment; Bidirectional Print Position Adjustment Procedure - Epson LG1-1070 Service Manual

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4.2 BIDIRECTIONAL PRINT POSITION ADJUSTMENT

This section describes how to adjust the bidirectional print position to ensure correct printing alignment.

4.2.1 Overview of Bidirectional Print Position Adjustment

This printer prints characters when the carriage is moving in either direction (i.e., from left to right or
from right to left).
Adjustment is necessary to ensure that the printing of characters in one direction is properly aligned
with the printing of characters in the opposite direction. For example, if the print position is out of
alignment, printing of a vertical line shows staggering because of the skew effect.
It is important to readjust the bidirectional print position if anything has been done to the gear
arrangement that might affect this printing alignment. By making the timing lag a fraction during
printing while the carriage moves from right to the left, it is possible to line up the printing done in
this direction so that it will match the printing done in the left to right direction. This procedure to alter
the timing is called bidirectional print position adjustment.
The degree of bidirectional printing skew differs, depending on the unique characteristics of each
to each printer. The unique skew correction value for each printer has to be written to EEPROM on the
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BOARD ASSY., MAIN (C062 MAIN BOARD).
I Whenever the PRINTER MECHANISM, or the BOARD ASSY., MAIN (C062 MAIN BOARD) itself, is
changed during sevicing, the bidirectional print position must be readjusted and a new bidirectional
skew correction value must be written to EEPROM.

4.2.2 Bidirectional Print Position Adjustment Procedure

Initial operation
Before performing the bidirectional alignment adjustment, complete the initial operation below:
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Position the LEVER, G, ADJUST at position O. * Verify that the DIP switch 1-6 is on).
Feed at least 10 lines.
Turn the printer off.
NOTE: The printer enters unidirectional printing mode automatically from the top of form to the line
10 position on the paper, because this improves paper-feed accuracy. Therefore, you must
perform the bidirectional alignment adjustment after 10 lines or more have been fed.
Adjustment operation
The alignment procedure is as follows:
1. Turn the printer power on while pressing the ALT, LF\FF, and LOAD\ EJECT buttons.
2. The printer enters draft mode and prints the reference value and "1" characters for 4 lines.
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