Printing Process; Printing Methods - Epson STYLUS COLOR 3000 Service Manual

EPSON Stylus COLOR 3000

Printing Process

The steps below describe how the ink is ejected from each nozzle with the on-demand ink jet system.
Step 1 Normal State
In this state, no print signals are sent to the PZT (Piezo electric element). The PZT does not move and no
pressure is added to the ink inside the cavity, so it is kept at a constant level.
Step 2 Ejecting State
Print signals are sent to specific nozzles via the printhead driver circuit to activate the PZT. The common
driver circuit on the control board produces the voltage that activates the PZT. When the voltage is sent to
the PZT, the PZT is displaced and the pressure in the cavity changes. The ink ejects as a result.
Ejecting State
Normal State
Piezo
Cavity
Nozzle
Ejected Ink
Figure 2-3. Printing Operation States
When the control board stops sending print signals, the PZT moves back into place. The cavity returns to its
normal size, making the pressure negative. The negative pressure absorbs the ink from the cartridge,
refilling the cavity with ink for the next printing motion.
Leftover ink can stick to the nozzle surface and increase viscosity in the nozzles, causing printer
malfunctions. To prevent this, ink is periodically absorbed and drained into the waste ink drain pads by the
pump mechanism.
Ink viscosity varies depending on the temperature around the printhead. A thermistor is attached to the color
printhead to keep the drive voltage at a proper level for the detected printhead temperature.

Printing Methods

EPSON micro dot printing
Both black and color printouts can be made in EPSON micro dot printing mode. In the micro dot printing
mode, the printer uses less ink to create sharper dots. This expands the gradation range for a more delicate
tone. This mode is available when 1440×720-dpi paper or glossy film is selected.
Microweave printing
In this mode, the printer prints 1 line with multiple passes by using specific nozzles for each pass. The paper
is fed in smaller increments. Since this mode eliminates a white banding problem, image quality is improved.
However, there is a decrease in paper feed speed. Microweave printing can be selected through the printer
driver.
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EPSON Stylus Color 3000 Service Manual