Epson 420i - Manual (Page 23)

Double-Strike Printing
In the double-strike mode, the second dot is printed 1/120 inch down from the initial
dot on a vertical line. The double-strike process requires 2 passes of the printhead.
Example: (STANDARD) (DOUBLE-STRIKE)
Buffer
This printer is equipped with an 18K-byte communication buffer which allows the
reception of data during printing. Thus, even for large data transfers the computer
is free to perform other tasks.
Printhead Protection
During high-density printing, a heat detector within the printhead protects the coils
from damage due to overheating, by reducing print speed. The sensor recognizes
two temperature warning levels. At level one, a 200 ms pause in the print cycle oc-
curs before the next line is printed. At temperature level two, a 5-second pause in
the print cycle will occur, allowing the heat to dissipate. The ON-LINE lamp blinks
during the 5-second halt.
RAM (Memory) Error Detection
(performed only during the initialization operations)
When a RAM error is detected, the buzzer sounds, the POWER lamp blinks, and
the error state is entered.
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