Oki IP-6620 Maintenance Manual page 530

(1) Print head
The print heads used in this printer are driven by an electrostriction transducer, and the ink is
ejected by applying signal voltage pulse on the piezo elements to distort these elements and
change the volume of the ink pressure room.
The printer is equipped with six or seven print heads (six or seven colors). Each print head uses
508 nozzles to support high-speed printing.
- Drive frequency
Drive frequency is 17.7 kHz per nozzle for standard mode.
- Temperature control
Drive voltage is controlled depending on the temperature since the ink viscosity changes with
the temperature.
- Air damper
To prevent the printer head meniscus damage by movement of the ink inside the ink tube
due to the carriage acceleration, a damper is provided to mitigate the pressure fluctuations.
- Head heater
The heaters mounted on the print heads increase the print head temperature to the specified
one during printing. They are controlled by the engine firmware that uses temperature data
detected by the head thermistor.
(2) Ink cartridge
Ink is contained in a laminated film pack. The ink capacity is 1500 ml for each color, and the pack
is set into the plastic ink tray. A board with an IC chip is mounted at the surface near the edge of
the cartridge. Varied information is stored in the memory of this chip during production, and
various logs are stored from the printer while in use.
- Memory ID: Ink type ID (color)
- Date of manufacture
- Printer record log: Ink consumption
OKI Data Infotech Corporation CONFIDENTIAL
Chapter 8 Operation Mechanism
8-9