Canon W8400 Series, Service Manual, Page: 63 / 224

Chapter 2
2-13
F-2-12
e) Printhead maintenance unit
The printer performs cleaning operations of the printhead at the carriage homeposition.
In the wiping operation, the printhead installed in the carriage are wiped as the purge motor rotates when the carriage is stopped at the carriage
homeposition. The maintenance jets are the carriage passes through the maintenance jet tray, located on the right side of the platen, while the carriage is
moving forward. The suction operation is performed using the suction cap of the purge unit.
f) Gap adjustment unit
The printhead height adjustment lever located on the right side of the carriage works in coordination with the height adjustment cam. The height adjustment
rollers located at the bottom-right edge of the carriage front are moved up and down by this mechanism, and this moves the head holder position up or
down to change the gap between the face of the printhead and the media. Detection of the vertical height of a print head height adjustment lever is performed
by print head position H sensor H/L.
g) Registration sensor unit
The resistration sensor at left bottom of the carriage consists of two LEDs and receiver sensor.
h) Rail cleaner unit
The rail cleaner at far right of the carriage is used to prevent contamination of the rail.
i) Internal temperature detection
A thermistor for measuring the internal temperature is installed on the head relay PCB on the rear of the head holder.
2.3.2.4 Printhead
2.3.2.4.1 Structure of printhead
0009-1513
A printhead has six nozzle arrays. Each nozzle can be controlled individually so that a six-color discharge action is performed by a single printhead.
a) Nozzle arrays
Each nozzle array provides 1280 nozzles arranged in a two-column staggered pattern. Each column is comprised of 640 nozzles separated by an interval
of 1/600inch and is arranged in a staggered pattern to form 1280 nozzles separated by an interval of 1/1200 inch.
Maintenance-jet tray
Carriage home
position sensor
Carriage relay PCB
Shaft cleaner
Head relay PCB
Carriage cover
sensor
Registration sensor
Printhead height adjustment lever
Carriage home position edge
Print head position sensor (L)
Print head position sensor (H)