HP ElectroInk vs. other ink processes

HP ElectroInk is a proprietary Liquid Electro Photography ink technology developed exclusively for HP Indigo digital presses. It offers a number of advantages over both dry-powder xerographic toner and standard conventional ink. For example:

  • The consumption of HP ElectroInk has little dependence on substrate properties, unlike conventional printing or dry-powder xerography.
  • In conventional offset printing, different inks are needed for papers or non-absorbent films, and the viscosity of the ink differs for each type of paper stock. Highly absorbent papers can increase offset ink consumption by up to 50%.
  • Dry-toner xerography is heavily dependent on the electrostatic properties of the substrate. Small changes in relative humidity can result in large changes in print quality. The high fusing temperature that is needed for the process also limits the choice of paper supported by the process.
Text Comparison

Xerography (powder tone)

HP ElectroInk (type magnification)

Dot Structure Comparison

Conventional offset

HP ElectroInk

HP ElectroInk advantages

Edge sharpness. Viewed at high magnification, HP ElectroInk clearly forms sharper images compared to xerographic dry toners (Figure 3) and even offset lithographic dots (Figure 3 and 4).

Dot gain and color consistency. HP Indigo digital presses can vary the dot gain to allow the consistent, precise control of the exposed dot size and optical density.

Image gloss. Similar to offset inks, HP ElectroInk images match the gloss of the underlying substrate, from rough to dull to high gloss. The HP ElectroInk layer is only about one micron thick and accentuates the media's characteristics by following the "hills and valleys" of the substrate surface rather than filling them in.

Instant image drying. HP ElectroInk solidifies as soon as it transfers to the substrate, so the finished print emerges dry and can be finished immediately.

Light fastness. The encapsulation of the pigment sub-particles in HP ElectroInk helps prevent oxidization and the effects of relative humidity. The color durability of the printed images, including light fastness, equals and often exceeds conventional offset inks.