Hewlett-Packard created the PCL printer language (simply
referred to as “PCL” elsewhere in this manual) to provide an
economical and efficient way for application programs to control
a range of printer features across a number of printing devices.
HP has evolved both the definition and implementations of PCL
to provide the optimal price and performance balance. PCL 5
represents a new breakthrough in price/performance leadership.
Its features were selected in direct response to customer
requests. HP will continue to lead enhancements to the PCL
printer language to deliver powerful technology advances.
PCL commands are compact escape sequence codes that are
embedded in the print job data stream. This approach minimizes
both data transmission and command decoding overhead.
HP PCL formatters and fonts are designed to quickly translate
application output into high-quality, device-specific, raster print
images.
PCL printer language commonality from HP printer to HP printer
helps to minimize printer support problems and protect HP
printer customer investment in applications and printer driver
software.

PCL printer language structure has been useful to guide language
functionality growth and command syntax definition. The PCL printer
language has evolved through five major levels of functionality driven
by the combination of printer technology developments, changing
user needs, and application software improvements. The five phases
of the PCL printer language evolution are:
The PCL printer language model succeeds because the following
points are observed:
z All HP LaserJet printers implement PCL printer language
features consistently.
z HP printers implement the above language feature groups in very
cost-effective formatters.
z HP printers have the ability to ignore most unsupported
commands.
PCL 1 Print and Space functionality is the base set of
functions provided for simple, convenient, single-user
workstation output.
PCL 2 EDP (Electronic Data Processing) /Transaction
functionality is a superset of PCL 1. Functions were
added for general purpose, multi-user system printing.
PCL 3 Office Word Processing functionality is a superset of
PCL 2. Functions were added for high-quality, office
document production.
PCL 4 Page Formatting functionality is a superset of PCL 3.
Functions were added for new page printing
capabilities.
PCL 5 Office Publishing functionality is a superset of PCL 4.
New publishing capabilities include font scaling and
HP-GL/2 graphics.

PCL Commands
PCL commands provide access to the printer’s PCL control structure.
The PCL structure controls all of the printer’s features except those
used for vector graphics, which are controlled by the HP-GL/2
commands.
PCL printer commands consist of two or more characters. The first
character is always the ASCII escape character, identified by the ?
symbol. ? is a special control code which identifies the subsequent
string of characters as a printer command. As the printer monitors
incoming data from a computer, it “looks” for this character. When this
character appears, the printer reads it and its associated characters
as a command to perform and not as data to print.
Note PCL printer commands (other than single-character control codes)
are also referred to as escape sequences. The terms printer
command and escape sequence are used interchangeably
throughout this manual.
Once a PCL command sets a parameter, that parameter remains set
until that PCL command is repeated with a new value, or the printer is
reset to its user default environment. For example, if you send the
printer a command to set line spacing to 3 lines/inch, each page
prints 3 lines/inch until the printer receives a different Line Spacing
command, or the printer is reset.

HP-GL/2 Commands
HP-GL/2, vector graphic commands are two letter mnemonic codes
designed to remind you of the function name (such as IN for Initialize).
Following the two letter mnemonic may be one or more parameters,
which identify details of how to process the command. For additional
information on HP-GL/2 commands, refer to Chapters 17 through 23.
PJL Commands
PJL (Printer Job Language) commands provide a different type of
printer control. Unlike PCL and HP-GL/2, which control the placement
of dots on the printed page, PJL supplies job-level control. One of the
main features PJL offers is the ability to switch printer languages
(personalities) between jobs. For example, applications supporting
PJL can print one job using PCL, and then print the next job using
PostScript or another printer language, without any operator
intervention.
PJL also provides two-way communications with the printer. For
example, PJL can request information from the printer such as printer
model, configuration, printer status, and job status. PJL also can be
used to change the printer’s control panel settings and modify the
message displayed on the control panel.
The PJL language is designed to be used by application developers
and technical support personnel only

Printer Reset
A Printer Reset restores the User Default Environment and deletes
temporary fonts, macros, user-defined symbol sets, and patterns. A
Printer Reset is performed by sending the E
CE command, or through
the printer’s control panel (see the printer User’s Manual). The Printer
Reset command is described in Chapter 4, PCL Job Control
Commands.
The E
CE command prints any partial pages of data that may have
been received. The control panel [RESET] discards any formatted
pages which have not yet been printed.
Both resets ( E
CE and the control panel [RESET] ) return the
HP-GL/2 settings to their default values. E
CE used in HP-GL/2 mode
returns the printer to PCL mode in addition to resetting the print
environment. The HP-GL/2 IN (Initialize) command resets HP-GL/2
settings to their default values without affecting the PCL settings
(refer to the Initialize command described in Chapter 19, The
Configuration and Status Group, for additional information).
Notes Hewlett-Packard strongly recommends the use of both the E
CE
command and the E
C%–12345X command (Universal Exit
Language/Start of PJL — also referred to as the UEL Command) at
the beginning and end of each job. (The order of these commands is
critical. Refer to Table 4-1 for an example of their usage.)
The UEL Command (E
C%–12345X) has the same effect as the E
CE
command, and also enters PJL Mode of operation for printers that
support PJL (refer to “Universal Exit Language Command” in Chapter
4 for more information). The E
CE command should be included to
ensure backward compatibility (the UEL command is ignored if
received by a printer that does not support PJL).

Text printing may be restricted to a specific area within the logical
page using the Left Margin, Right Margin, Top Margin, Text Length,
and Perforation Skip Mode commands. This area is known as the
text area.
The left margin defines the distance between the left edge of the
logical page and the left edge of the text area. The right margin
defines the distance between the left edge of the logical page and the
right edge of the text area. The width of the text area is the distance
between the left and right margins. The top margin defines the
distance between the top of the logical page and the top of the text
area. The text length defines the length of the text area which in effect
defines the bottom margin. The perforation region is the distance from
the bottom of the text area to the top of the text area (top margin) on
the next page. The text area is shown in Figure 5-4.
In general, characters are printed when they fall within the text area.
However, characters can be printed between the bottom of the text
area and the top of the text area on the next page only if perforation
skip is disabled. Characters are printed outside t