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

DECIMAL

VALUE

BINARY

VERTICALLY

CODE

TO ROTATED DATA

EQUIVALENT

BYTE

BIT IMAGE

PATTERN

 

 

 

 

128

MSB

 

 

 

 

64

 

 

 

 

 

32

 

A

=

65

=

16

 

8

 

 

 

 

 

 

4

2

1

=

Figure 4–3. Bit Image Pattern from an ASCII Character

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

4–3

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Printronix P3000 Series manual Bit Image Density, Control code ESC K selects the Single Density Mode