Commodore MPS-801 - Printing Method

PRINTING METHOD
This printer is based on the uni-hammer printing system which is quite different from other impact
dot printing systems. In this system one dot is printed when the hammer strikes a raised ridge on
a platen.
Hammer
PRINTING MECHANISM
THERE ARE 18
RIDGES EVENLY
SPACED AROUND
THE PLATEN
The timing for the hammer depends upon the dot signals generated by the revolution of the rota-
tion detector which is attached to the motor shaft. The hammer motion, the left to right movement
of the hammer, and the revolution of the platen are precisely synchronized.
As the platen rotates, for each ridge, seven dot signals are sent to the CPU. The CPU then selects
whether or not to activate the print head hammer for the given dot according to the character pattern
being printed. The hammer can be activated seven separate times as one ridge passes by the hammer-
head. The
hammer head is slanted to compensate for the constant left to right motion of the hammer.
Each pass
of a ridge causes one dot colu mn to be printed.
P4
Hammer Head
PLATEN ROTATION
~ 1 st dot column
I f 2nd dot column
......
,.....
><
><
>-<
><
~
, ...... ><
---1
?'"
-;>-<
>"
>-<
><
)-<
'-'
'-"
PI P2P3P~P5
Ridge No.
6