(3.1) Switching pump
The pump switching unit switches the application target of the negative pressure generated by the
pump between the head cap for black ink, the one for color ink, and the air vent cap.
When the purge cam is in a head capping position and the carriage lock fits the head cap unit
tightly over the print head, the pump switching unit is switched to the opening tube to the
atmospheric air so that the pressure in the head caps and air vent cap returns to the normal
atmospheric pressure.
Head cap for color ink
Color drain tube
(3.2) Draining ink
The tube pump consists of a pump gear and tube roller. As the pump gear rotates, the tube roller on
its circumference squeezes the main drain tube looped around the pump gear, forcing its content
toward the ink absorber box and creating negative pressure.
Main drain tube
For details about the purge mechanism, see [ 4 ] below.
Print head
Head cap for black ink
To air vent cap
Pump gear
Tube roller
3-26
Black drain tube
Pump switching unit
To opening to
atmospheric air
Main drain tube
(Purge_3_2)
Tube pump
(TubePump)
Confidential