Printhead - Epson Stylus Photo 720 Service Manual

EPSON Stylus Photo 720 / EPSON Stylus Photo EX3

2.1.2 Printhead

The printhead uses a new developed E-CHIPS+1 head method and Stylus Photo 720 /
Stylus Photo EX3 can perform multiple shot printing and variable printing. Printhead
nozzle configuration is as follows.
32 nozzles x 6 rows (nozzle pitch of each row: 1/90 inch)
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Ink configuration: black, cyan, light cyan, magenta, light magenta, yellow
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(aligned in this order)
The basic operating principles of the printhead, which plays a major role in printing,
are the same as previous models; on-demand method which uses PZT (Piezo Electric
Element). In order to uniform the amount of ejecting ink, each printhead has its own
head ID (10 figures for Stylus Photo 720 / Stylus Photo EX3) which adjust PZT
voltage drive features. The printhead stores the head ID to EEPROM and generates
appropriate PZT drive voltage to prevent amount of ink from varying by printheads.
Following explains printhead basic components.
PZT
o
PZT is an abbreviation of Piezo Electric Element. Certain amount of voltage
expands and contracts PTZ. The drive wave generated on MAIN board drives PZT
and PZT pushes the top cavity which has ink stored to discharge the ink from each
nozzle on the nozzle plate.
Ink Cavity
o
The ink absorbed from the ink cartridge goes through the filter and then is stored
temporarily in this tank called "cavity" until PZT is driven.
Nozzle Plate
o
The board with nozzle holes on the printhead surface is called Nozzle Plate.
Filter
o
When the ink cartridge is installed, if any dirt or dust around the cartridge needle is
absorbed into the head, there is a great possibility of causing nozzle clog and
disturbance of ink flow, and finally causing alignment failure and dot missing. To
prevent this problem, a filter is set below the cartridge needle, where ink is filtered.
Operating Principles
I/C Sensor Lever
Nozzle Plate
Figure 2-2. Printhead Sectional Drawing
Overview
Nozzle Selector Board
Ink Cartridge
Needle
Filter
Cavity
PZT
Revision A
32