Carriage Drive Mechanism - Brother MFC4820C Service Manual

4.2.3.4

Carriage drive mechanism

The carriage, on which the print head unit and the ink supply section of the needle tube ASSY are
mounted, travels to the right and left when driven by the carriage motor (DC motor).
The motor rotation is transmitted to the CR timing belt (1/24 inch pitch). The carriage, which is
supported and guided by the carriage rail, is secured to the CR timing belt. Clockwise and
counterclockwise rotations of the carriage motor move the carriage to the right and left,
respectively.
On the back of the carriage is a CR encoder sensor which tells the control circuitry the current
carriage position based on the carriage home position by using the encoder strip (1/150 dpi pitch)
attached to the lower chassis of the engine unit.
The carriage travel speed is 30, 15 or 7.5 ips according to the print resolution. The controller
controls it using PD control.
Carriage motor
CR timing belt
Carriage rail
CR encoder sensor
CR encoder strip
CR idle pulley
CR motor gear
Engine unit
Carriage
Aging
The initial adjustment of the PWM value can be achieved with Function code 69 in the
maintenance mode. It automatically selects CR drive parameters that minimize speed variation and
that are suitable for the current carriage drive mechanism by aging the carriage. If cogging or
uneven carriage movement is noted, performing this aging may solve such problems. (For details
on Function code 69, refer to Chapter 7, Section 7.5.16.)
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