The 'digital' process is toner-based and is commonly known as 'print-on-demand' or 'on-demand-printing.' The digital printing set-up can range greatly in size, quality and complexity.
The Process: Using a finely-focused beam of light (laser), high-speed laser printing exposes the artwork to photosensitive material located on a drum or belt. Very fine, electrically-charged toner is attracted to the image on the drum/belt which possesses an opposite charge. This attraction acts like a temporary ‘glue’ (similar to static electricity). The toner particles are then transferred to the paper and fused to it with heat and/or pressure. This process occurs four times - one pass for each color (cyan, magenta, yellow and black). Equipment can vary greatly: some models have four toner and developer units on a rotating wheel, while others add all four colors to a plate before placing the image on paper. More expensive printers have a complete printer unit (laser assembly, drum and toner system) for each color.
An important distinction is that digital, unlike offset, uses no film, imagesetters, plates, platesetters, or photochemicals, and produces no waste.