The Deregulation Of the Digital Press
Unlike toner-based, variable data presses such as those made by Indigo and Xeikon that have a fixed cost per sheet or conventional offset presses that require plates to be imaged through a labor-intensive external process, direct imaging offset presses produce plates for medium-length runs directly on-press from digital job files.
Direct imaging offset presses offer the same benefits as conventional offset presses. This includes high- speed printing at up to 10,000 to 15,000 sph, lower incremental costs to print additional sheets, larger format sizes and offset color printing quality. But by imaging plates on-press, even the most basic direct imaging offset presses allow faster makeready for color and registration, resulting in reduced operating costs on short- to medium run-length jobs.
Direct imaging offset presses actually fall into two groups. The first group is made up of conventional offset presses retrofitted with a digital imaging system. These "hybrid" direct imaging systems include Heidelberg's GTO-DI and Speedmaster DI products, the Adast DI and Akiyama's J Print.
In the second group are the new-generation direct imaging offset presses, which have been redesigned with operations that are largely controlled through digital technology. These digitally integrated offset presses—represented by the 74 Karat press from Karat Digital Press and Heidelberg's Quickmaster DI—maintain the high quality of offset while providing the benefits of increased automation by integrating with an all-digital prepress workflow.
The new-generation, digitally integrated offset presses make the most of all-digital workflows to control the operation of the press and provide even greater benefits. Using a computer front-end to drive the press makes it possible to direct a range of functions under program control, such as automatically adjusting for paper thickness, paper type and ink sets. Despite their differences, both types of direct imaging offset presses bypass the extra steps of film-based platemaking, reduce capital equipment requirements for imagesetters, analog-based proofing and external platesetting units, and eliminate the process of hanging and registering plates on-press.