Printer Mechanism - Epson Stylus 820 Service Manual

Operating Principles

2.2.1 Printer Mechanism

The printer mechanism for this printer uses a drop-on-demand ink jet system similar to the system used on all
other EPSON ink jet printers. However, the printhead in this system has been completely redesigned to make
it more compact and ensure a high level of reliability. The figure below shows the structure of the printhead
and ink supply system.
o Piezo When a drive pulse (voltage) is applied, this element pushes the vibration plate,
compressing the cavity for ink ejection from the nozzle.
o Cavity Ink supplied from the ink cartridge is stored in this space and is ejected from the nozzles
when the vibration plate compresses this area.
o Nozzles These eject ink against the paper's surface in response to the application of the
print signal. There are 64 (black head) or 60 (color head) individual nozzles
making up the printhead.
2-2
Sensor Actuator
for Ink Cartridge
Cartridge Needle
Ink Filter
Ink Supply Tube
Figure 2-2. Structure of Print Head
Stylus Color IIs / Stylus 820
Head Drive Board
Head Cover
MLP Set
Cavity Set
Nozzle Plate
Rev. A