Service manual

Rev. B Mechanism Configuration and Operating Principles 2-3
TM-U200 Series (Type B) Service Manual
Confidential
Print head unit movement
When the carriage motor is driven and the carriage motor gear moves in the direction of arrow B
(forward rotation), the rotational power is conveyed to the belt drive pulley, then the belt. Next,
the carriage sub assembly, which is fixed to the belt, moves in the direction of arrow B.
When the carriage motor gear rotates in the direction of arrow A (reverse rotation), the carriage
sub assembly moves in the direction of arrow A.
Wire movement when a single dot is printed
When the specified print head drive pulse is input to the drive coil, the iron core is magnetized,
and the actuating plate is pulled in the direction of arrow A. This action pushes the wire toward
the platen. When the wire strikes the ink ribbon and paper against the platen, a single dot is
printed. (The “platen” is the portion of the paper feed frame being struck by the wires during
printing.)
When energizing of the drive coil is completed, the wire and actuating plate are returned to the
standby position by the wire return spring and actuating plate spring.
Figure 2-3 Print head unit movement
Figure 2-4 Printing
Belt
Carriage motor gear
Belt drive pulley
Carriage sub assembly
B
A
Actuating
Paper roll
Ink ribbon
Wire return
Drive coil
plate
spring
Wire
Wire guide
Iron core
Platen