Nearly all digital presses use electrophotographic processes or ink-jet technology for imaging. Many digital presses have the capability of printing on both sides of the paper in one pass. This is known as duplex printing. Like conventional printing presses, digital presses are available in both sheet-fed models and web-fed models.
The output speed of a digital press is often determined by the type of application that is printed. A job that has no variable data will often print at the full speed rating of the press because the RIP (Raster Image Processor) is required to process the digital information only once for static applications. The RIP is the device that converts the elements for the digital print application into a format that can be understood by the press. The press can run at full speed because the digital information does not have to be reprocessed for every page that is printed, as is the case for variable data applications. The speed of the RIP becomes slower as the quantity of variable data increases. Since printers/RIPs are "page-oriented" devices, (meaning that a full page is the smallest item that is processed rather than individual elements on a page), the RIP must process the entire page even though many of the elements from page to page may be identical.
PPML/VDX (Personalized Print Markup Language/Variable Data Exchange) is a language developed for variable data applications that allows text and graphics (or objects) that are common to every page, to be reused without the need for reprocessing. Only the variable data is processed for each page, which increases the output speed of the digital press. The PPML/VDX standard allows the RIP to be "object oriented" rather than "page oriented".
Digital presses are part of a totally electronic workflow also known as computer-to-print technology. The price per copy of an application printed on a digital press is usually the same regardless if 1 copy is printed or 1,000 are produced. The cost per copy may be higher than the same job printed with conventional processes, but the press time spent producing the job is less than what it would be if printed by conventional means, therefore digital presses allow for more jobs to be printed within the same amount of time required to produce one job with conventional printing presses.