Difference between HP Indigo Printing and Traditional Printing

While different from conventional printing, HP Indigo digital presses still retain some familiar elements.

Here are a few comparisons:

  • HP Indigo digital presses, like conventional presses, use liquid ink to print an image. The major difference, however, is that HP ElectroInk technology directs the ink electronically using charged particles in the ink.
  • HP Indigo digital presses use a light sensitive plate that attracts ink. Unlike conventional printing that uses a fixed (etched) plate that cannot change, the HP Indigo Photo Imaging Plate (PIP) is a dynamic light sensitive plate that can be re-imaged with different information on every revolution of the printing cylinder. The ink is attracted to the PIP by an electrical charge, rather than a physical transfer from ink tray to cylinder.
  • HP Indigo digital presses do not limit ink coverage to 200%; coverage can reach beyond 400%, ensuring color depth and saturation.
  • From the PIP, the ink is transferred to a blanket that transfers the ink as in conventional offset printing. The blanket acts as a shock absorber and pressure pad to ensure even ink transfer to the substrate. This enables the HP Indigo digital press to support a wide range of substrates of varying surface texture and thickness. HP Indigo technology offers a number of advantages versus offset, including the elimination of the incomplete transfer of ink (ink splitting) that is a characteristic of conventional offset litho.
  • Unlike conventional offset printing, the HP Indigo blanket also transfers 100% of the ink to the substrate. The total transfer of ink from the blanket allows the same set of cylinders to be used to print the complete sheet, ensuring precise color-to-color registration and color consistency throughout.
  • The HP Indigo can create an entirely new separation, in a different color, for every rotation of the cylinder. This is called "on-the-fly color switching" and is the technology that enables the HP Indigo digital press to print fully collated, duplexed and individually personalized sheets.