Fujitsu ULTIMA90 Maintenance Manual page 8

APTC mechanism
Paper feed mechanism
HCPP mechanism
The printing mechanism fit into the bottom cover. And Upper Cover holds it in position.
a. Carriage
The carriage supports the removable 24-wire print head, and slides left and right on the stay shaft.
The ribbon feed gear system moves the ribbon in one direction regardless of carriage movement. It
has four sensors: LRES, TOFL, TOFR and APTC sensor. The LRES detects both left and right ends
of the carriage movement. The TOFL/R detects the edge (top, left, right, bottom) of paper. The APTC
sensor detects the surface of paper for control the gap between the print head and the paper.
b. Carriage drive mechanism
The stay shaft and the stay guide (upper angle) support the carriage; the stepping motor and timing belt move
the carriage horizontally.
c. Paper feed mechanism
There are two stepping motors. One of them drives the rollers and another one drives tractors.
d. Host-controlled paper path (HCPP) mechanism
The HCPP mechanism switches power transmission to the tractors. Three states are possible: front tractor is
selected, rear tractor is selected, and cut sheet is selected. Switching is possible through software or by the
control panel. The paper on the platen is unloaded to the park position or ejected, and then the paper feed path
is switched. When switching from a cut sheet to continuous forms, the continuous forms are automatically
loaded to the print position.
e. Automatic paper thickness control (APTC) mechanism
The APTC mechanism adjusts the gap between the print head and the paper surface. Before start printing, the
print head is approach to the platen until APTC sensor is pressed against the paper surface. And then the print
head is returned by a certain distance so that the gap (actually between the print head and the paper) is
properly adjusted regardless of the paper thickness.
f. Paper sensors
Figure 1.6 Mechanism of DL7600
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