Fast Finishing in Digital Printing

Fast Finishing in Digital Printing
Marginal Column
Content

March 2016

 

Machines for print finishing need to keep pace with the progress in digital printing in terms of speed and flexibility. VITS International, a company from the United States, has created an innovative solution for this with the help of a complete solution from Bosch Rexroth.

Whether individualized books or personalized mailings – when it needs to be variable, digital printing is the method of choice. The data is sent directly from the computer to the printer, making it possible for images, text and pages to be changed over flexibly. Digital inkjet printers may have been inferior to web offset printing in the past in terms of speed, but nowadays they can reach speeds of anywhere from 200 to 300 meters per minute. This technique has thus proven itself to be appropriate for high-volume printing, as well. But increasing the speed, together with the variable print data, makes the subsequent finishing more complicated. In spite of varying content, a readable end product needs to come out after all the cutting, sorting and joining together of the printed pages.

The American company VITS International, based in Blauvelt in the state of New York, recognized this problem early on. “We decided to take a leading role in developing robust, industrial-strength finishing systems that have the technical capacity, speed and sophistication to support both offline and inline finishing with the highest quality,” says Deirdre Ryder, President and CEO of the manufacturer, which has meanwhile become number one in the world.

A fast solution for inline and offline

With the SPRINT Variable Data Finishing System, the company has designed a new machine that processes the different media at a speed of over 450 meters per minute to form a finished product. Thanks to the patented “Clear Channel” register control, it accurately cuts thousands of pages per hour with maximum precision. No other print finishing machine had ever accomplished this – until now.

The SPRINT system is available in two versions: a version that processes a single paper web directly from the digital printer as an inline system, and a second version where the end product, for example a book of several preprinted paper webs, is produced. The latter version works as a stand-alone offline system. “As we looked at the challenges, we came to the conclusion that only Bosch Rexroth would be able to provide the precise control technology we needed,” according to John Salamone, Director of New Product Development for VITS.

The SPRINT system consists of modular, independently driven components. The inline version has ten to twelve axes and the more complex offline version up to 30. Each of the modules performs a specific task in order to produce a finished product out of the printed paper web: from web guiding, folding and cutting up right through to stacking the pages. A major challenge in the finishing process is getting a precise cut-off register even with several paper webs. “Nothing is ever printed perfectly – the length of print can vary by plus or minus ten thousandths of an inch from page to page,” Salamone explains, “that doesn’t sound like much, but after a hundred pages the registration can be off significantly.”

Intelligent automation solution

To solve this challenge, VITS commissioned Bruce Parks from Parks Consulting International, a system integrator with extensive experience with Rexroth automation solutions for printing systems. For the controls, he and the team from VITS opted for the automation platform IndraMotion for Printing. “IndraMotion for Printing provides engineering tools that work right out of the box to accomplish most of the web handling tasks,” says Parks. Using the PLCopen-compliant functional components of this automation solution as a basis, the SPRINT team could, for example, integrate the “Clear Channel” register control into the system. It was the very first time that VITS put its confidence in a complete solution from Bosch Rexroth. Deirdre Ryder is very pleased with the results: “We now have Rexroth-equipped machines located all around the world. Their performance and reliability is so good that I am proud to say they are working flawlessly.”