Compaq P5000 Series - Manual (Page 15)

Line Matrix Printing
15
Line Matrix Printing
Your printer creates characters and graphics by a printing technique called
line matrix printing. Line matrix printing consists of printing patterns of ink dots
on paper, an entire line at a time.
Each text character is stored in memory as a pattern of dots on a logical grid
called the dot matrix. (See Figure 2.) The actual ink dots are made by a row of
hammer springs mounted on a shuttle that sweeps rapidly back and forth.
Printer logic divides every printable line into horizontal dot rows. The hammer
springs put dots at the required positions for the entire line by striking a
moving ink ribbon and the paper.
Figure 2. Dot Matrix Character Formation
Unlike serial dot matrix printers, which form complete text characters one at a
time with a moving printhead, a line matrix printer divides each printable line
into horizontal dot rows, then prints a dot row of the entire line with every
lateral sweep of the shuttle. (See Figure 3.)
During each sweep of the shuttle, the hammers print dots at the required
positions in the dot row. At the end of a sweep, the shuttle reverses direction,
the paper advances one dot row, and the hammers print the next row of dots
as the shuttle sweeps in the opposite direction.
Dot Column
Dot Row
Character Row
Character Column
Matrix visible only to
the printer
Ink dots formed by
hammer tips