220.127.116.11 Printing Process
Steps bellow describes how the on-demand ink jet system ejects the ink from each nozzle in the
<Step 1> Normal state
When the print signal is not output, PZT also dose not move in the waiting state (normal state).
<Step 2> Ejecting state
When the print signal is output from the C202 MAIN board, Nozzle selector IC mounted on the head driver
board latches the data once by 1-byte unit. Appropriate PZT latched by nozzle selector is pushed in to the
cavity by applying common voltage from the C202 MAIN board. By this operation, ink that is stored in the
cavity pops out from nozzles.
During the ink charging or cleaning operation, the ink left in the cavity is vacuumed out by the Pump
mechanism via Capping unit, then is ejected to the waste ink tank. The cavity is refilled with ink from the
Ink Cartridge during the printing or other operations. The viscosity of the ink tends to change according to
the temperatures around the heads, and the change in viscosity results in the low printing quality. This is,
however, avoided by attaching the thermistor directly to the driver circuit board. It is used to determine the
proper drive pulse automatically according to the detected temperature.
18.104.22.168 Printing Methods
This printer has 3 kinds of different dot to compose the print image; Normal dot, Double firing Normal dot,
and Micro dot. Each dot is selected to control printing depending on the conditions such as the paper type
and the print resolution set through the printer driver.
Normal dot / Double Firing Normal dot printing mode
Normal dot/Double firing Normal dot printing modes are available for the both black and color
printings. Normal dot printing mode is designed to form single dot with 2 head drive pulses. With this
mode, the dot diameter is expanded to solve the white banding problem which occurs during solid
printing at 360 dpi. This printer is, however, designed to use less ink than other printers do to perform
printing at 1440 dpi, the maximum solution on the horizontal line. Therefore the Double firing Normal
dot and Normal dot used for this printer is considered equivalent to the Normal dot mode and Micro
dot mode used for previous ink jet printers respectively. Double firing Normal dot mode is normally
selected for printing at 360 dpi, and the Normal dot mode is used for printing in 720 X 360 dpi or 720
dpi X 720 dpi, depending on the paper type.
EPSON Micro dot printing
Both black and color printings can be performed in the Micro dot printing mode. In the Normal dot
printing, one dot is formed with 2 pulses. On the other hand, EPSON micro dot printing mode forms
one dot with single pulse using less ink. As mentioned above, the Micro dot printing for this printer is
controlled to use less ink to create images at 1440 dpi, the maximum solution on the horizontal line.
This mode is used for printing at 720 dpi or 1440 dpi by controlling the firing duty of the ink.
Micro Weave Printing
This function is developed to enhance quality in graphic image by eliminating white banding which
occurs on each line. This printer is equipped with a new micro weave printing mode and is controlled
to form a horizontal line using 2 different types of nozzle. With this mode, the printer can prevents
color inks from mixing with each other before drying and can provide clearer colors in the output. The
Micro Weave printing can be selected through the printer driver.
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Figure 2-3. Print Process