On a recent call with one of my clients we were discussing a variety of issues related to their business. We started off by discussing the state of the business, their current challenges, new opportunities, and their goals for the coming year. As our conversation continued, the client asked about what technology would be best for their Digital Print Area; cut-sheet printers or roll-fed devices? As our discussion continued, we discussed many factors but ultimately it came down to three key areas: Application, Volume and Time.
First of all, understand that high-speed digital production printing has developed rapidly over the last five or so years. There have been significant advancements in electrophotography devices as well as the introduction of a new class of very high-speed ink jet presses. Traditional cut-sheet printers (defined as primarily 8.5″ x 11″ paper sheets) have also improved with increases in capabilities, features and speeds. Although cut sheet paper is effective for many applications, there is a limitation on throughput speed during the printing process. The upper limit for feeding cut sheet paper through any printer is about 80 linear feet per minute. (350 images per min) Faster speeds create a physical problem with paper handling and paper control becomes unpredictable. Additionally registration can become a problem. Registration on roll-fed devices is usually tighter on front-to-back (0.3 mm) compared to cut-sheet (0.65 mm). Roll-fed digital devices can range in speed from 115 feet per minute (500 images per min) up to 1,000 linear feet per minute (4300 images per min). Roll-fed devices can also handled roll stocks from 6.5 inches wide up to 30 inches wide in some cases.
From an application standpoint, digital printers, whether cut-sheet or roll-fed, are mainly targeted at production applications. You wouldn’t want to tie up a production machine running a basic copy job. By production applications, I’m referring to applications such as high volume transaction printing, direct mail, book printing and publishing applications. Cut-sheet printers usually are equipped with multiple paper trays and are much better suited for applications that might require multiple paper stocks such as standard or colored papers, tabs, and covers all in one document. Roll-fed units have one paper source and are designed for one type of stock. Paper stock weights have traditionally been one of the strength of cut-sheet printers. Typically a cut-sheet printer will have the capability of running as low as 16# bond (50gsm) up to 110# cover stock (300 gsm). Roll-fed devices usually can run as light as 10# bond (40gsm) to 54# bond (200gsm).
Volume is an important consideration and usually plays a major part in the type of device selected. Roll-fed devices are more expensive than their cut-sheet counterparts and therefore require much higher volumes for cost effectiveness. Normally, roll-fed devices start making sense somewhere around 2 million monthly impressions. However, depending on the device, many roll-fed devices can easily handle volumes up to 40 million impressions per month. Typically you would need a minimum of 3 or more cut-sheet printers to produce the same volume as one roll-fed device. Also, depending on the timeframe requirements of the volume to be produced, applications that require millions of impressions can be printed in a shorted span of time. (i.e., five million pages are required in a three-day period) Cut sheet devices are not as effective as multiple printers would be needed to handle large volume demands. For these types of jobs, roll-fed printers are significantly more productive and offer greater cost effectiveness. Additionally operator invention is limited as a roll of paper can last anywhere from 2 ½ to 6 hours depending on the device. Paper handling is reduced significantly and reloading of rolls is quick and simple which saves considerable time.
So next time you are evaluating the various digital printing technologies for your shop, start with the basics of application, volume, and time. If you focus on these key factors you will be able to determine what technology to implement and you will be able to determine what is the right technology for your shop.