Epson LQ-860 - Impact Printer, User Manual

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Data Flow Process
The diagram below shows the basic data flow process up to the time
output is printed.
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The data received by the printer is first stored in the input buffer.
Data is picked up from the input buffer and then processed
through the data analysis section. There it is divided into
graphics image data, control codes, and printable characters.
Graphics data is sent to the print buffer (line buffer), while the
control codes and printable characters are sent to the control
code processing section.
The control code processing section converts printable
characters into the specified character patterns. The control
codes are also processed along with the printable data.
After processing, the character and image patterns are stored in
the print buffer (line buffer) for printing.
Printing begins when either of the following conditions are met:
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The buffer is full. For example, when a line length is set for 80
columns, printing begins when the 81st data item is received.
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A print control code is sent. Printing begins when the printer
receives any of the following print control codes: CR, LF, VT,
ESC J, ESC j, or FF.
9-2 Command Summary