H Unidirectional printing
Unidirectional printing is a big word that means printing in
one direction only. SG- lo/ 15 normally prints when the printhead
is moving in both directions. But once in a while you may have
an application where you are more concerned about how the
vertical lines align than with how fast it prints. SG-lo/15 lets
you make this choice. The table below shows the commands for
controlling how SG- lo/ 15 prints.
Table 8-3
Prking direction commands
One-time print in one STAR 1 <‘ESC > “ < ”
direction IBM 1 <ESC> “<”
Try this program to see the difference that printing in one
direction makes.
10 'Demo unidirectional printing.
20 LPRINT CHR$(27) "A" CHR$(7) ; 'Line spacing = 7/72".
34) FOR I = 1 TO l@
44) LPRIN'T 'I/"
50 NEXT I
60 LPRINT : LPRINT
70 LPRINT CHRS(27) "U" CHR$(l) ; 'Turn on unidirectional
printing.
80 FOR I = 1 TO 10
90 LPRINT ";"
100 NEXT I
110 LPRINT CHR$(l2) CHR$(27) "@" ; 'Form feed, master
reset.
Here is what you will get. The top line is printed bidirectionally,
and the bottom is printed undirectionally. You will have to look
hard because there isn’t much difference.
Let’s analyze the program. Line 20 sets the line spacing to 7/72
of an inch so that the characters that we print will touch top to
bottom. Lines 30-50 print 10 vertical line characters. Then line
70 sets one-direction printing and the vertical lines are printed
71