Paper Feed Mechanism And Operation; Paper-Low Detection Mechanism And Operation - Ithaca 75 User Manual

Ribbon Feed Operation
As the Space Motor rotates, the Ribbon Gear on the Space Motor Shaft rotates
to drive the Drive Gear in the Ribbon Cartridge via the Ribbon Feed Gear
Assembly. As a result, the Ribbon is fed.
In bi-directional printing, the Ribbon Gear rotational direction reverses every
time the Carriage reverses direction. In this case, the gears in the Ribbon Feed
Gear Assembly switch the rotational direction to feed the Ribbon in a fixed
direction.
Ribbon Cartridge
A one-way-feed endless ribbon is used. Ink is replenished by the built-in ink
tank in the ribbon cartridge. This assures clear printing.

PAPER FEED MECHANISM AND OPERATION

The printer feeds paper by rotating the Feed Roller, which is driven by the Line
Feed Stepper Motor through a speed reduction gear. The paper is pinched
between the Feed Roller and the Pressure Shaft on the Forms Compensation
Assembly. This maintains constant pressure regardless of the thickness of the
paper or form.
The Paper Feed Mechanism consists of the following items:
♦ Stepper Motor with Gear
♦ Reduction Gear
♦ Feed Roller
♦ Pressure Roller Shaft
The Paper Feed Stepper Motor is mounted on the right side of the Base Plate,
and its rotation is transmitted to the Feed Roller through the Reduction Gear.
The Feed Mechanism is designed such that when the Stepper Motor rotates 48
steps (360 degrees), paper is fed 0.167 inches (4.32 mm).

PAPER-LOW DETECTION MECHANISM AND OPERATION

When paper is present in the printer, a small lever is prevented from
interrupting the path of a sensor located on the Bucket Assembly. When the
printer runs low of paper, the lever falls and interrupts the optical path of the
sensor, causing a paper low condition. This indicates that there are ten to twelve
feet of paper left.
Appendix B: Theory of Operation
87