This year’s Hunkeler Innovation Days focuses on Next Level Automation, a topic that is central to Contiweb’s product strategy and development programs. With our roots in heat-set web offset we understand the importance of interconnected equipment that shares process information for high level automation. Nowadays, the same is true for web inkjet printing, with successful automation being achieved through wider process improvement.
Automation in digital printing has become essential due to a lack of qualified personnel worldwide; any jobs that can be automated help to ease the problem. Successful automation also means far fewer production errors and therefore almost continuous operation. That benefits digital printing by making very low-run print jobs economically viable, which supports the trend to personalization and one-to-one marketing.
There are several aspects to successful automation in the digital printing world. For example, individual processes like manual paper reel changes need automating, and peripheral processes need bringing into the overall system. That means adopting standards that allow key manufacturers’ equipment to be interconnected, forming a single integrated solution. Configuration itself should be automated, too, so that print providers lose no time reconfiguring single machines in a press line.
Above all, automated processes must maintain continuous, unbroken production, so avoiding equipment jams and paper breaks while keeping uptime near the targeted 100%.
Let’s take a look at some of the challenges and solutions for web inkjet print producers.
Reduce paper warping and jams in finishing
The printing process cannot do without drying. For inkjet printing, the moisture from the aqueous inks must be evaporated. To meet the ever-increasing demands for higher production speeds, an enormous amount of heat must be rapidly applied, and paper temperatures can easily exceed 100°C. As a result, not only does the moisture from the ink evaporate, but also the moisture from the paper.
Paper with a low moisture content isn’t as strong and is thus susceptible to tearing or cracking. Problems also occur when the moisture content of the paper returns to an equilibrium with the environment in an uncontrolled way.
That introduces paper waviness and curling of the edges, which can cause paper jams and tears in the finishing line. Besides affecting productivity, it also makes automation less effective by reducing the quality of the printed product… sometimes even leading to unmarketable products.
Correcting paper moisture levels to maintain uptime
Such finishing line and print quality problems can be prevented by remoistening the paper. Contiweb’s Digital Fluid Applicator (DFA) does this using plain tap water.
The DFA applies moisture using steel contact rollers that are mechanically pressed against the paper web, and sleeves which are pulled over them. The sleeves ensure a more even distribution of water (optionally mixed with silicone) on the paper web. An even distribution is important because it ensures maximum reduction of waviness and warping of the paper edges – after printing and drying of the paper web – without the drawback of cockling.
Settings can be stored and recalled using the touch-screen Human Machine Interface. Even better would be to connect the DFA to the press console, which would enable print providers to control the DFA centrally and automate settings (the DFA already implements standardized communication protocols for when press job management systems can accept them). The press console will then store the characteristics of the print job and choose the right settings for the DFA, to eliminate manual interference.
Remoistening is also the ideal time to apply silicone oil. This protects the printed material by reducing mechanical stresses during inline finishing. The paper absorbs the water, with the oil staying on top and protecting the finished product. Silicone works like a lubricant – it is not visible and will be absorbed into the paper after a few days.
Contiweb already has over 600 remoistening systems in heat set web offset. The Digital Fluid Applicator is compatible with continuous web-fed inkjet presses from all the key manufacturers who are exhibiting at the Hunkeler Innovation Days this year. That includes Canon, HP, Kodak, Ricoh and Screen. You can see Contiweb’s DFA in action when you visit the Screen stand in Hall 2 and there is a static unit on display at Contiweb’s booth in Hall 1.
Automated metering for coatings helps avoid reconfiguration
To protect printed items for longer than just during finishing, you should apply other coatings. Post coating can improve product quality by adding a gloss or matt coating. It also protects items like postcard mailers that could otherwise be damaged during mail handling. For self-mailers, the addresses are printed on the items themselves, so post coating prevents them from becoming unreadable.
However, coaters using an anilox system often need to be manually reconfigured for different coating layers. Instead, patented automated metering allows Contiweb's Variable Coater to vary the coating layer for each paper side without changing components like the rollers and sleeves.
The lateral moving cassettes in the VC allow easy adjustment to paper web width. The coater can communicate directly with the web press console. It can automatically adjust the required coating layer and web width without mechanical operator interference, based on stored recipes in the HMI. Like the DFA, the VC will be a perfect fit in the future for next-level automation by implementing communication protocols that create a constant dialog with the press controls. This can be based on the specifications of the print job, and the correct values can be set with no operator intervention.
(Visitors to the Contiweb stand can pick up a free sample booklet, post-coated on the VC).
Interlinking machines is increasingly important
Print providers are facing huge pressures to produce cheaper and faster, and automation is the best approach to realize this. That means not only automating the individual processes, but also ensuring that the individual machines in a production line all communicate with each other. This helps overcome the lack of qualified personnel, too.
For Contiweb, interlinking machines is a no-brainer. Our heritage in heat set web offset with 3,300 machines has made central control of print jobs standard. We’ve designed each piece of Contiweb equipment so that print providers can enhance print quality, increase uptime, and reduce production costs. Interlinking our equipment brings even more benefits.
You’ll find Contiweb’s automation expertise on show at the Hunkeler Innovation Days on booths 204/205 in Hall 1. Come and meet the Masters of automation, and talk to our experts about your needs!
Digital Fluid Applicator
The Contiweb Digital Fluid Applicator is a remoistening system for smooth processing in finishing lines and enhanced product qulity. Click for more information.
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