Capping Mechanism - Epson PH890 Service Manual

EPSON Stylus Photo 890/1290

2.1.4.4 Capping Mechanism

The capping mechanism, which is driven by the pump unit, caps the printhead closely
to maintain air tightness inside the cap. This operation is required to vacuum ink from
the ink cartridges, printhead, and cap. Also, to moisten the inside of the cap while the
printer power is off, this mechanism works to keep the cap and the printhead surface in
a tight contact. This function prevents ink from clogging while the printer is not in use.
Negative
pressure is
released here.
Closed state
OPERATING PRINCIPLES
Previous Models
Ink Ejection
Hole
Valve
Released state
Figure 2-10. Valveless Capping Mechanism
The capping mechanism of this printer is a newly designed valveless capping
mechanism. So, unlike previous printers, it does not integrates an air valve. The air
valve is usually equipped to remove bubbles created inside the cap by releasing the
negative pressure. However, due to change in the ink sequence, the new valveless
capping mechanism enables the printer to maintain the initial ink charge and cleaning
effects at the same level as before. Figure 2-10 outlines the valveless capping
mechanism.
Stylus Photo 890/1290
Ink Ejection
Hole
There is no air valve
assembled.
Overview
Revision B
44