Printronix ThermaLine Series - Manual (Page 54)

Commands 4–10
Incremental Data Fields
The incremental data fields feature allows alphanumeric (and bar code) data
fields to automatically update numerically or alphabetically with just one set
of data sent from the host computer. A maximum of 65,535 forms can print
with incremental fields automatically updated.
Alphanumeric incremental fields can be used with fixed (static) data input as
part of the Create Form mode or with dynamic data supplied in the Execute
Form mode. Incremental data fields cannot be used with Overlay data.
Dark Printing
A DARK parameter, available in the Alpha, Reverse, and Bar Code
commands, is a double–strike feature which produces bolder, darker text,
denser black backgrounds for reverse print, and extra–dark, more readable
bar codes. The application of the dark feature differs between line-matrix and
thermal printers, as described in the following paragraphs.
Thermal Printers
Reverse and Bar Code commands automatically print in the DARK mode in
thermal printers; therefore, a DARK parameter in the command line is
ignored. However, a DARK parameter used with alphanumeric text in the
ALPHA command will print using a bold font. In any event, print speed is
not reduced when using the DARK parameter with thermal printers.
Line-Matrix Printers
The extra darkness provided by the DARK parameter improves the Print
Contrast Ratio (PCR) and effectively extends the life of the ribbon. For bar
codes, the PCR describes the difference in light reflection between the bars
and spaces as a measurement of light/dark contrast in order to judge when a
printed bar code will not be dark enough to be read with accuracy by a
scanner.
The extra dots used to produce the darker bar code do not change the overall
width of the wide bars. Figure 4–2 illustrates how the DARK parameter adds
two extra dot columns to wide bar code bars without increasing bar width.