Output Hardware | Printers | Inkjet
Inkjet | Bubblejet

Inkjet/bubblejet printer - operation

Inkjet

1. The CPU builds the page in memory.
2. A sheet of paper is fed into the printer.
3. Sets of "pixel" lines are sent to the printer.
4. Droplets of ink are sprayed from a print head through electrostatically charged plates that control the direction of the inkjet spray.

Note: increased quality may be achieved by increasing the number of passes for each set of lines.

• Thermal ink (HP), uses a resistor to quickly boil reserved ink, creating a vapor bubble that pushes ink out of the nozzle.
• Piezoelectric (eg. Epson stylus). Uses tiny crystals in the ink reservior that expand when electrified, forcing ink from the print head

Bubblejet

• When ink in the thin nozzles of the print head is heated rapidly, bubbles are produced.
• These bubbles expand so rapidly that the droplets of ink are ejected from the nozzle.
• Heat is generated by applying power to heating elements built into each nozzle.
• Each pulse of power produces the effect described in "Bubblejet -Principles".

1. When the pulse is applied, heat is generated in the heating element, and the neighbouring ink is vaporized almost instantly. The bubble which is produced generates a pressure wave which ejects a droplet of ink from the nozzle.
2. After the pulse passes, the ink vapor condenses, drawing fresh ink into the nozzle.