Mechanisms; Print Head Mechanism; Print Head Carrying Mechanism - Star Micronics NX-1020 Technical Manual

4. Mechanism

4-1. Print Head Mechanism

The print head consists of 9 needle wires and 9 print solenoids. The following explains how each needle wire operates
during printing.
(1) When the print solenoid is energized, the clapper is attracted by the iron core and the needle wire is driven toward
the platen.
(2) This needle wire hits the platen via the ink ribbon and paper. A single dot is printed on the paper.
(3) When the print solenoid is de-energized, the needle wire is returned to its original position by rebound energy and
spring and clapper holder (leaf spring) force.

4-2. Print Head Carrying Mechanism

The print head carrying mechanism consists mainly of a carriage, timing belt, carriage motor, and home position detector.
(1) Carriage
The carriage is supported horizontally by means of the carriage stay and rear angle, and it moves from side to
side with the print head mounted above it. A timing belt is clamped to the base of the carriage and a shield plate
is mounted at the base for home position detection.
(2) Timing Belt
The timing belt is suspended between the timing pulley of the carriage motor and the timing pulley of the tension
lever, and it maintains a constant tension.
The timing belt is also clamped to the base of the carriage so that it can move the carriage accurately with driving
force from the carriage motor.
(3) Carriage Motor
The carriage motor is a HB (Hybrid) type, four-phase and 192-pole pulse motor, which is driven by pulse signals
from the control circuit. The rotational rate depends on the number of pulses per unit time. By varying this rotational
rate (that is, the carriage carrying rate), the size of the horizontal letters can be changed in each print mode.
Fig. 2-20 Outline of Print Head Mechanism
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THEORY OF OPERATION