The ink passage comprises ink tanks, a printhead, caps, a waste ink collector, ink tubes interconnecting the mechanical components, and a suction pump that is

driven to suck inks. It supplies, circulates, sucks and otherwise handles inks.

The ink passage (per color) is schematically shown below, along with the ink flow.

Agitation plate

a) Supplying inks from the ink tanks to the ink supply valve assembly

The ink tanks each contain an ink to feed the printhead.

Head differences allow the inks to flow from the ink tanks to the ink supply valves.

b) Inks flowing from the ink tanks into the subbuffer

As the inks flow from the ink tanks to the subbuffers due to head differences, air infiltrates the ink tanks through air passages in the subbuffers to keep its internal

pressure constant.

When the ink stored in a subbuffer exceeds a predetermined level, it flows into the absorber under the ink tank through the air passage.

c) Supplying inks from the ink supply valves to the printhead

The ink stored in an ink tank flows to the printhead when the suction pipe is driven with the ink supply valve opened and the head capped.

As an ink is sucked from the caps, it flows into the waste ink absorber under the maintenance cartridge or purge unit.

d) Ink supply while printing

The ink supply valves are kept open while printing, so that inks are being constantly fed to the printhead under the negative pressure of the nozzle assembly caused

by discharging inks.

Further, waste inks sucked in a cleaning operation and inks from borderless printing flow into the waste ink absorber under the maintenance cartridge and into the

waste ink box.

When an ink tube filled with ink, opening all whole ink passages (by opening both the ink supply valve and the printhead fixer lever with an ink tank yet to be

installed) could cause the ink in the ink tube to flow backward due to a head difference, leaking through the hollow needle in the ink tank.

As a precaution, never open all the ink passages at the same time while the ink tubes are filled with inks.

e) Agitating the ink in an ink tank

To prevent the pigment ink stored in a tank from settling, the ink needs to be agitated.

The ink supply valve is continuously opened and closed to cause the ink to flow back into the tank for agitation. Each ink tank contains an agitating plate to aid in

agitating of the ink. (An agitating plate is also installed in the dye ink tank.)

-Operation timing: Whenever a new tank is installed or 168 hours have expired since the agitation was last carried out (agitation is carried out regardless of whether

printing or cleaning is in progress).

-Ink supply valve open/closed: 30 times (30 seconds)

If 336 hours or more have elapsed, the ink supply valve open/closed count and the time to the next session of agitation are varied according to the elapsed time.

Mechanical Drive Unit

Ink or air flow

Ink tank

Sub buffer

Ink supply valve

Joint

Suction pump

Maintenance cartridge

F-2-8

Carriage unit

Printhead

Cap