Epson 3000 Piezo, Cavity, Nozzle, Ejected Ink, Normal State, Ejecting State, <Step 1> Normal state, ￿Micro weave printing, <Step 2> Ejecting state

EPSON Stylus COLOR 3000

2.2.2.2 Printing Process

Steps bellow describe how the ink is ejected from each nozzle with the on-demand ink jet system.

<Step 1> Normal state

No print signal is applied to the PZT (Piezo electric element). In this state, the PZT does not displace and no pressure is added to the ink inside the cavity. Therefore the pressure in the cavity is kept at a constant level.

<Step 2> Ejecting state

Print signal is applied to a specific nozzle via the head driver circuit to activate the PZT of the nozzle. The voltage which activates the PZT is produced in the common driver circuit on the control board. When the voltage is applied to the PZT, the PZT displaces and the pressure in the cavity changes. Then the ink ejects as a result.

	Normal State		Ejecting State
Cavity		Piezo

NozzleEjected InkFigure 2-3. Printing Operation States

When no more print signal is applied to the PZT, the PZT recovers from the displaced status. With this process, the cavity also returns to its normal size, which brings the pressure negative. The negative pressure in the cavity then absorbs the ink from the cartridge to fill the cavity with the ink again for the next printing motion. The ink which was not used for printing adheres on the nozzle surface and increases viscosity in the nozzles, and it causes printing malfunction. Therefore the ink is periodically absorbed and wasted into the waste ink drain pads by the pump mechanism. Ink viscosity varies depending on the temperatures around the printhead. Since the change in the ink viscosity leads to decline in print quality, the thermistor is attached to the color printhead to keep the drive voltage at a proper level based on the detected printhead temperature.

2.2.2.3 Printing Methods￿EPSON micro dot printing

Both black and color printings can be performed in the normal dot printing mode and EPSON micro dot printing mode. In the normal dot printing mode, the printer uses less ink to create sharper dots. Therefore the gradation range is expanded in more delicate tone. This mode is available when the 1440X720-dpi paper or glossy film is selected.

￿Micro weave printing

In this mode, the printer prints 1 line with multiple passes by using specific nozzles for each pass. The paper is also fed in smaller increments for this operation. Since this mode eliminates white banding problem, the graphic images quality is improved. However, decrease in paper feed speed is inevitable. The Micro Weave printing can be selected through the printer driver.

Rev. A 2-3