Compuprint 4247-Z03 Programmer Manual - Manual (Page 21)

Chapter 1. Personal Printer Data Stream (PPDS)
The 4247 Model X03/Z03 printers implement a subset of PPDS. The environment in which the printer data
stream processor operates is described below.
Print Job Processing
There are no PPDS controls that explicitly define print job boundaries. A print job for the 4247 is
established by the host system and consists of any set of related print objects. A print job could be as
short as one character or could be many pages long.
As an aid to the printer operator, the printer provides a PROCESSING indicator on the operator panel.
When the PROCESSING indicator is flashing, it indicates that data is currently being received, processed,
or printing, or that data is buffered in the printer but cannot be immediately printed. If the PROCESSING
indicator is not lit, then all print jobs have been completed.
Configuration parameter values can be changed at any time; however, to obtain predictable results,
changes to operator panel configuration parameter values should be made before the print job is sent to
the printer and after the previous print job has completed printing. Changing configuration parameter
values while a print job is in progress may cause unpredictable results.
We recommend the following to ensure that your print jobs run correctly:
v Establish a known print environment, and end any previous print job. Start each print job with a Set
Initial Conditions control. This control resets the printer environment to the default settings. You can then
set additional controls depending on your print job environment.
v End each print job with a FORM FEED control. This control causes all data to be printed, and the
current position is set to the top-of-form position.
v If a print job is abnormally terminated, the job should be canceled. See “Cancel Print” in “Chapter 2.
Understanding the Operator Panel” in the User's Guide for your printer.
Page Printing Concept
The 4247 processes print jobs in terms of pages, as well as in lines and columns. A page is a logical entity
whose boundaries are defined by the width and the page length. These boundaries are established during
printer initialization using the printer defaults, and can be changed using the Configuration Menu or by
issuing the appropriate data stream controls.
As a job prints, the printer controller maintains both the logical position and the physical position on the
page. If a print job does not end with a proper job terminator (for example, FORM FEED), then:
v All data for the current page may not print
v The next print job may be misaligned on the form
v Residual data from a previous job could print with the new job.
Page Presentation
Many PPDS commands (tabs, margins, line spacing, for example) are described in terms of the
presentation surface. A presentation surface is a two-dimensional surface upon which the printer positions
symbols according to controls embedded in the incoming data stream. The presentation surface is defined
in absolute terms by the width and depth parameters of the page size control commands (Set Page
Length, Set Horizontal Margins, for example). The physical print position does not move outside the range
of these two parameters. The left margin (LM) and right margin (RM) are variable parameters within the
presentation surface. The logical print position does not move outside the range of the vertical margins nor
outside the horizontal margins + 1. The following figure shows the presentation surface and the
1