Digital Printing

Digital printing really refers to any printing process where the image is created by computers. This may be anything from a inkjet printer, which applies little drops of liquid ink in a controlled pattern through a print head consisting of small holes using either electro static repulsion or vascular action. Or a direct to plate printer that creates temporary plates for each job that is run over the press. The process shown above is laser printing, which is one of the most popular commercial methods for producing full color prints.

Laser printing works similarly to xerography, in that it is based on the principal that like charged particles repel and differently charged ones attract. A silicone composite photoreceptor belt is passed under an electrostatic charger that gives the entire belt a negative charge. A laser then focuses light on specific areas of the belt to reverse the charge and therefore create the image. Dry ink, or toner, which is plastic particles mixed with an agent to give them a negative charge, is then applied to the belt and sticks to the positively charged areas. For one color printing, the toner is then applied directly to the paper, and in full color printing, each color is applied to transfer belt which then applies the entire image to the paper.

The main advantages of digital printing is its ability to print variable data and it is relatively low cost set up. It is popular for small runs of just about any type of document.