8
Height vs. LPI
Each font supports printing at 1.5, 2, 3, 4, 5, 6, 8, 9, and 10 Lines per Inch (LPI). Variable LPI is
accomplished by changing:
a.
the inter-line gap (number of dot rows skipped between successive lines);
b.
the character's vertical size.
Character vertical size may be increased by repeating rows. In most emulations, each character dot row
is printed:
4 times at 1.5 LPI;
3 times at 2 LPI;
2 times at 3, 4, and 5 LPI;
once at 6, 8, 9, and 10 LPI.
Character vertical size may also be adjusted by changing the vertical DPI from the normal values given in
Table 2. For example, at 8 LPI, descenders touch the top of upper case characters if normal row spacing
is used, so a “compressed character” option is provided to give a more proportional inter- line gap. For
example, 8 LPI DP lower case characters use 9 rows; at the normal 72 DPI spacing, there is no inter-line
gap, each line touching the previous. With the "compressed character" option, the rows are spaced at 96
DPI, resulting in a 3-dot (3/96") inter-line gap.
Character Width
Character width and horizontal dot spacing is based upon units of 1/240 inch or 1/180 inch, with the
actual dot spacing varying according to the font style and matrix used. Character width is set to about
85% of the total character cell space, with the remaining 15% for inter-character gap. OCRB character
width is set at about 70% of cell space, to allow a 30% inter-character gap for machine readability.
Table 3 Character Width, 6800 Series
10 CPI
Matrix
12 CPI
Matrix
15 CPI
Matrix
Dot Resolution/Spacing/Dot Density
Draft/DP CDF 120 / 2 / 60 120 / 2 / 60 120 / 2 / 60
Draft/DP Enhanced 120 / 2 / 60 240 / 3 / 80 240 / 2 / 120
NLQ 180 / 2 / 90 180 / 2 / 90 240 / 2 / 120
OCR-A Standard/Enhanced 120 / 2 / 60 - -
OCR-A High Density 240 / 3 / 80 - -
OCR-B 180 / 2 / 90 - -
Cell Columns/Char Columns/Max Dots
Draft/DP CDF 11 / 9 / 5 9 / 7 / 4 7 / 5 / 3
Draft/DP Enhanced 11 / 9 / 5 16 / 13 / 5 11 / 9 / 5
NLQ 17 / 15 / 8 13 / 11 / 6 11 / 9 / 5
OCR-A Standard/Enhanced 11 / 9 / 5 - -
OCR-A High Density 22 / 19 / 7 - -
OCR-B 17 / 15 / 8 - -