In the printer, a "formatter" converts the
print data to dot patterns, storing enough dots to make a complete
physical cycle, usually a single pass of a print head or a single
page. The formatter accepts print data in one or more forms, sometimes
called printer languages. Formatters that handle more than one such
language may include commands to switch between languages, or they
may switch automatically by analyzing the data stream.
Such languages fall into two general categories:
Printer languages such as PCL, HPGL, and ESC-P. These languages use
data streams in which the
data consists of (1) text bytes, (2) 2-5 byte command strings for
horizontal and vertical spacing and line- image (vector) graphics,
and (3) strings of bit-image (raster) graphics. This data is easily
and quickly converted.
Page description languages (PDLs), such as PostScript (PS)
and PCL-V. These languages are actually a subset of the printer
languages group, but they use much more complex data streams. Consisting
largely of verbose English phrases and programmatic constructions,
PDLs allow more complex data manipulations than the simpler printer
languages, but require more time to convert.
Choosing the right printers for your network involves more
than determining a printer's output speed. PostScript printers can
accommodate most inconsistencies that PCL printers cannot, so if
possible, make sure your printers are PostScript compatible.
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