Epson Stylus Photo 925 - Various Setting Options; Using the LCD Control Panel

EPSON Stylus Photo 925 Revision A
Operating Principles Overview 30
V Ink Cavity
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.
Figure 2-3. Print Head Sectional Drawing
2.1.2.1 Printing Process
This chapter explains the process in which the print heads of On-Demand inkjet
printers eject ink from each nozzle.
1. Normal State:
When no printing signal is sent from the C475 MAIN board, or no PZT drive
voltage is applied, PZT does not change shape, therefore PZT does not squeeze the
cavity. Ink pressure inside the cavity is kept normal.
2. Ejecting State:
When the print signal is output from the C475 MAIN board, IC (Nozzle Selector)
located on the print head unit latches data once by 1-byte unit. An appropriate PZT
latched by the nozzle selector is pushed into the cavity by the common voltage
applied from the main board. By this operation, ink stored in the cavity spurts out
from nozzles.
Figure 2-4. Print Head Printing Process
Nozzle Selector Board
Needle
Ink Cartridge
Filter
Cavity
PZT
Nozzle Plate
CSIC
CSIC Connection Circuit
* Head ID for print head
is stored in EEPROM.
Ink Path
PZT
Ink Cavity
Nozzle
Nozzle plate
PZT drive voltage
Normal State
Ejecting State