Continuous-feed Inkjet: The Web Paper Challenge
Inkjet Printing Productivity chart
Pages Printed Via Inkjet chart
Inkjet Printing Applications chart
Water In, Water Out
Both types of inks contain a lot of water, and the water creates a challenge. Dennis Essary, director of digital papers for NewPage Corp., explains: “The water has to go in and leave pigment on the surface, and then the water has to be driven out by heat. This requires a surface that looks smooth, but is actually quite open.” This is especially challenging for coated papers, and more so for glossy papers, where coatings are smooth and appear to create a continuous, closed surface.
Paul Bradshaw, senior vice president of publishing papers at Appleton Coated LLC, agrees, and adds that uncoated paper and coated paper present opposite challenges. “Uncoated paper will let the water absorb, but traditional coated won’t let the water in. You need to let the water in, but keep pigment on the surface.”
There are three approaches to the paper challenge: “ordinary” papers, i.e., untreated offset papers; on-press treatment; and specially treated papers designed for inkjet and produced by the paper mill.
Printers generally prefer to use the same paper for their offset printing as for their digital printing. Offset papers are typically less expensive than specially treated inkjet papers, and the use of offset papers simplifies inventory and merchant supply issues. Moreover, when a job is initially run offset, and then a shorter run reprint is digital, it is important that the paper is a match.
InfoPrint Solutions, initially a joint venture between IBM and Ricoh, launched the InfoPrint 5000 in 2007. Now known as Ricoh Production Print Solutions, the company has worked with virtually every mill at one time or another. Mike Herold, Ricoh’s worldwide product manager for inkjet technologies, advises that they have a process to test papers, and “we have a list of more than 300 papers that we support.” He adds that with heavy ink coverage, paper selection is more critical, and that “many factors affect document appearance. But, of the variables, paper is 60 percent.”