Appendix B IBM ProPrinter X24 and IBM ProPrinter II Commands
B.2.7 Graphics
The printer can operate in Bit Image Mode (bit map printing), to create illustrations and diagrams. In this way, the image is created by printing each byte received as a vertical line of 8 dots. A dot is printed for each bit set to "1" in the byte sent.
The least significant bit corresponds to the lowest dot on the line, while the most significant bit corresponds to the highest dot.
The graphic print commands only apply to one print line. The line end command CR/LF is only recognized when the printer leaves graphic printing to return to alphanumeric printing. As a result the number of bytes that can follow a command for graphics is limited by the maximum capacity of a print line (and the graphic resolution). The data that exceeds the capacity of the line buffer is ignored.
The graphic commands must therefore be repeated for each print line if you want to print an image consisting of several lines.
One line can contain both alphanumeric and graphical characters. To calculate the space that the alphanumeric characters occupy inside the graphics, a table is provided later on.
BIM Data/Capacity of the print line with various resolutions
BIM Resolution | 80 columns |
Normal (ESC K) | 480 |
Double (ESC L, ESC Y) | 960 |
Quadruple (ESC Z) | 1920 |
Space occupied by characters inside BIM data
The table below shows the relationship between the space occupied (as a number of bytes) by a normal character inside a mixed print line (text + graphics).
BIM resolution: | Normal | Double | Quadruple |
Pica (10 cpi) | 6 | 12 | 24 |
Elite (12 cpi) | 5 | 10 | 20 |
Condensed (17.1 cpi) | 3.5 | 7 | 14 |
