Epson Stylus Color 640 Service Manual page 46

EPSON Stylus Color 440/640/740
2.1.1.2 Printing Process
Following figures show the sectional drawings of normal state and
ejecting state of the printhead.
1. Normal State:
When the print signal is not output, PTZ also does not move in the
waiting state (normal state). (Refer to Figure 2-3.)
2. Ejecting State:
When the print signal is output from the C206 main-B/C255/C256/
C257 main board, IC (IR2C72C:Nozzle Selector) located on the
Print head unit latches the data once by 1-byte unit. Appropriate
PZT latched by nozzle selector is pushed into the cavity by applying
common voltage from the main board. By this operation, ink that is
stored in the cavity pops out from nozzles. (Refer to figure 2-4.)
Chapter 2 Operating Principles
PZT
Ink Course
Nozzle
Figure 2-3. Print Head Normal State
Figure 2-4. Print Head Ejecting State
Revision A
Cavity
Nozzle Plate
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