ENCAD 42e, Service Manual

Page: 28 / 162

28 Theory of Operation
Novajet PROe Series Service Manual
The Carrier Axis Drive
Figure 2-3. Carrier Axis Drive.
The Carrier Axis Drive moves the printer’s carrier assembly along
the length of the printer. The drive consists of a servo motor, linear
encoder strip, drive belt, and tensioning assembly. These items are
illustrated in figure 2-3.
The servo motor, drive belt, and tensioning assembly are the compo-
nents that actually drive the carrier assembly. The servo motor
drives the belt back and forth allowing the attached carrier assembly
to be repositioned as required. The tensioning assembly is spring
controlled and allows the proper amount of tension on the belt.
The linear optical encoder strip is used to obtain the printers accu-
racy along the axis of the printer. It is made with 150 parallel lines
per inch etched into it. By utilizing two optical encoder sensors that
are slightly off set from each other, and reading the leading and
trailing edges of the lines, a resolution of 600 dpi can be obtained.
The stepper and servo motors are controlled from the main printed
circuit assembly by the microprocessor.