IBM 6400 Series, Maintenance Information Manual

Page: 35 / 422

35
4
Principles Of Operation
Line Matrix Printing
The printer creates characters and graphics by printing patterns of ink dots on
paper, an entire line at a time. This technique is called line matrix printing.
Every text character is stored in printer memory as a pattern of dots on a
logical grid called the dot matrix. (See Figure 8.) The ink dots are made by a
row of small hammers mounted on a shuttle that sweeps rapidly back and
forth. Printer logic circuits divide every line of incoming data into horizontal dot
rows. The hammers put dots at the required positions for the entire
line by
striking an inked ribbon and the paper.
Figure 8. A Dot Matrix
1 12 Column No.
0.01389 inch
0.02 inch
First row and column
of next character column
(at 10 cpi)
Lowest descender dot line
First row and column of next
character line (at 6 LPI)
0.00835 inch
0.10 inch