Indigo Digital Press

Indigo is the name of a series of digital printing machines from Hewlett -Packard.

In 1993, the company brought Indigo (2002 acquired by Hewlett -Packard) with the E-Print 1000 the first full-color digital printer with liquid toner ( ElectroInks ) on the market. Due to the high, near- offset print quality, HP himself described this technology as " Digital Offset Color". In addition to the single-sheet ( sheet ) printers e - PrintPro , Turbo Stream, HP Indigo Press 1000 HP Indigo Press 3050 HP Indigo press 5000 and HP Indigo press s2000 were also the endless HP Indigo press w3200 and w4400 (formerly Omnius ) developed. The three core technologies, the HP Indigo Digital Offset Color are:

• ElectroInks (HP Indigo liquid toner )
• Thermal offset
• On- the-fly color switching

Electro Ink

HP Indigo liquid toner containing electrically charged particles, the toner itself, dispersed in a non-conductive liquid ( Isopar ). A dry toner as in the development of the toner image on the triboelectric charging of the particles is controlled. In contrast to the dry toner particle size is only 1 to 2 microns. Because of dusting and Respirability such small parts must be placed in a carrier liquid. The advantage lies in the possibility of higher resolution and edge sharpness as well as thin layers of paint, similar to offset printing. ElectroInks is offered in the standard process colors (cyan, magenta, yellow and black ) as well as additional colors.

ElectroInks is introduced as a concentrated paste in cartridges in the press. There it is pumped into the toner tank, and diluted with the carrier liquid (so-called imaging oil), wherein a consistent mixture of toner particles and carrier liquid is established.

Thermal offset

As with the HP Indigo offset used a blanket cylinder to Intermediate Drum ( ITM) reared blanket ( blanket ) to the developed color separation of the photoconductor drum ( engl. Photo Imaging Plate PIP) to be transferred to the substrate ( paper). The surface of the blanket cylinder is heated to about 160 ° C, so that the pigment-containing particles of the ElectroInk begin to melt and form a thin or soft, plasticized layer. Any existing carrier liquid evaporates. Upon contact with the cold paper solidifies the ElectroInks and remains firmly adhere to the paper surface. Due to this process, the paper exits the printer mostly dry and can be processed immediately.

Color switching

The HP Indigo technology, all color separations are printed with a single roll. This is possible because the blanket ( blanket ) a color separation almost completely transmits and that no residues of the previous image on the blanket.