65
30 FOR I=1 TO 10
40 LPRINT "I"
50 NEXT I
60 LPRINT : LPRINT
70 LPRINT CHR$(27);"Ul";
80 FOR I=1 TO 10
90 LPRINT "I"
100 NEXT I
110 LPRINT CHR$(12);CHR$(27);"@"
Here is what you will get. The top line is printed bi-directional-
ly, and the bottom is printed uni-directionally. You will have to
look hard because there isn’t much difference, but the bottom
vertical lines are perfectly aligned.
Let’s analyze the program. Line 20 defines 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 uni-directional printing and the vertical lines are
printed again. Finally line 110 sends a form feed to advance the
paper to the top of a new page, and then uses the master reset to
restore the printer to the power on condition.
You can also set the printer to print in one direction for one
line only by using the (ESC) “(” command. This command im-
mediately moves the print head to the left margin and then
prints the remainder of the line from left to right.