Space Mechanism And Operation; Ribbon Feed Mechanism And Operation - Ithaca 75 User Manual

86
Series 70 Maintenance Manual
After the character is printed, the magnetic flux of the permanent magnet
assembly attracts the armatures again which retract the print wires back into
the wire guide.
The Printhead has a built-in thermistor to prevent the coils from overheating.

SPACE MECHANISM AND OPERATION

The spacing operation is performed by the DC Motor driving the Carriage
Frame, which is guided by the Carriage Shaft mounted parallel to the Platen.
The DC Motor is mounted on the bottom of the Carriage Frame.
The Space Mechanism consists of the following items:
♦ DC Motor with Motor Gear
♦ Carriage Frame
♦ Carriage Shaft
♦ Space Rack
♦ Slit Sensor
♦ Slit Disk
The Carriage, with the Printhead and Space Motor mounted on it, moves
parallel to the Platen along the Carriage Shaft. As the Space Motor rotates
counterclockwise, the motor gear is driven to the right along the Space Rack,
and as a result, the Carriage is also driven to the right.
The spacing mechanism is designed such that when the Space Motor rotates one
turn, the Carriage Frame moves 0.8 inches (20.32 mm).
Motor rotation also rotates the Slit Disk, and the slits pass through the Slit
Sensor. The position of the Carriage Frame can be obtained by counting the
number of slits detected by the slit sensor.

RIBBON FEED MECHANISM AND OPERATION

The Ribbon Feed Mechanism feeds the Ribbon synchronously with the spacing
operation. The mechanism is driven by the Space Motor.
The Ribbon Feed Mechanism consists of the following items:
♦ Ribbon Feed Gear Assembly
♦ Ribbon Gear (Space Motor)
♦ Ribbon Cartridge