Service manual

Rev. B Mechanism Configuration and Operating Principles 2-11
TM-U200 Series (Type B) Service Manual
Confidential
movable blade drive pin in direction E to make the blade execute a cut. If the motor continues
rotating, the wormwheel makes one rotation and it makes the movable blade return to the
standby position and the cutting is finished.
Figure 2-14 Auto-cutter mechanism
Ribbon Switch Mechanism Unit
The ribbon switch mechanism unit consists of the carriage motor assembly, carriage sub
assembly, tension plate assembly, tension belt pulley, home position detector assembly, ribbon
frame assembly, ribbon frame spring, ribbon switch lever, ribbon release lever, and ribbon
release spring. The mechanism unit is placed at the left and right of the carriage sub assembly,
whose position is controlled by the number of carriage motor steps, using the home position as
the reference position. It switches between the black and red ribbon in the ribbon switch and
ribbon release areas outside the printing area.
Switching from Black to Red
When the carriage, sub assembly (print head unit) moves in direction E and reaches the ribbon
switch area, the ribbon switch lever is pushed by the ribbon switch section and moved to
position A (shown by the dotted lines). The ribbon assembly frame is pushed upward by the
push face for the ribbon frame. The detent face for the ribbon switch falls into the ribbon switch
lever hole in the ribbon frame assembly and the ribbon frame assembly is set to the red position.
Releasing from Red to Black
When the carriage sub assembly moves in the D direction and reaches the ribbon release area,
the ribbon release lever is pushed by the ribbon release section. Then portion C pushes the
ribbon frame assembly upward. At this time, the detent face for the ribbon switch is released
from the ribbon switch lever hole in the ribbon frame assembly and the ribbon switch lever is
returned to ribbon switch lever position B (shown by the solid lines) by the spring power of the
Wormwheel
Movable blade drive pin
Slot D
Arm
Wheel pin
Movable blade