Bit Image Density - Printronix P3000 Series User's Reference Manual

The relationship of ASCII character, decimal value, and Bit Image plot is shown in Figure 4–3.
The data bytes can be identified by their binary, octal, hexadecimal, or decimal equivalents.
These values are used to generate the Bit Image pattern.
Bit Image plotting is not limited to printable ASCII characters. You can plot Bit Image pat-
terns for any 8–bit data byte with decimal values ranging from 0 to 255.
The standard ASCII character chart and its equivalents are listed in Appendix A.
NOTE: Bit Image Graphics is recommended in the Data Processing print mode (120 x 72
dpi). Vertical density variations in other print modes may cause white horizontal bars or
overlapping of adjacent graphics lines; however, changing the line spacing can correct this
problem.
ASCII
CHARACTER
A

Bit Image Density

Bit Image graphics can be printed in different dot densities. Dot densities are selected by control code:
Control code ESC K selects the Single Density Mode.
Single Density Bit Image graphics in the Data Processing print mode are printed at 60 dots
per inch (dpi) horizontally and 72 dpi vertically. In the Correspondence print mode, the
horizontal dot density is 90 dpi and vertical dot density is 96 dpi. In the High Speed (HS)
mode, horizontal dot density is 60 dpi and vertical dot density is 48 dpi.
Control code ESC L selects the Double Density Mode.
The Double Density mode prints up to twice the number of dots per inch horizontally in the
same space as used for Single Density. The vertical dot density remains the same as in the
Single Density mode. Double horizontal density requires twice the number of input data
bytes to print the same length line as for Single Density. Printing double density reduces the
printing speed by half.
If each "1" or true bit is plotted, the result is a Bit Image plot of the ASCII character "A."
Graphics
BINARY
DECIMAL
VALUE
EQUIVALENT
= 65 =
Figure 4–3. Bit Image Pattern from an ASCII Character
VERTICALLY
CODE ROTATED DATA
TO
BYTE
128
MSB
64
32
16
8
4
2
1
BIT IMAGE
PATTERN
=
4–3