Push to automate printing

Drupa has long been the arena for press manufacturers to demonstrate that their presses can print three jobs in a row while an audience is hopefully glued to the presentation. In 2016 Heidelberg did just this to show of the Push to Stop concept, where the decision that one job is completed triggers the actions need to get the next job on press, washing of rollers and blankets, changing sheet formats, perhaps the paper in the stack, changing ink profiles and running a handful of sheets to check colour and fit, then it is off again until the stop button is pressed again.

Even before then Koenig & Bauer showed a non stop press. An eight-unit machine had four print units on impression and printing until the numbers had been completed whereon the press slowed, the units on impression sprang off and the second set of four units dropped into impression for a new job. The plates could be changed on the first units while the press continues to run. There have not been many takers. 

There are many installations of the Heidelberg technology. It is moot whether the users are making full use of the possibilities of the technology to maximise production efficiency. The benefits are more about enabling the press to be operated by minders without the sort of experience that recently retired staff have had. 

Both German manufacturers can ship machines with robots that take plates from a processor and load them into the correct print unit, removing the used plates and returning these for recycling. RMGT has shown a similar technology at the most recent Igas. The market is the online printer with ganged up jobs on the sheet and a constant flow of jobs to keep the press busy. Users reckon the technology enables them to be profitable on jobs requiring 500 sheets. 

This is the sweet spot for the Landa. There is no need for plates on the B1 nanographic press so no time lost in slowing the press, the plate change sequence and starting again. Instead the Landa runs at its steady pace, currently 6,500sph, switching instantly from job to job, providing the processing power is available.

All manufacturers can automate the start up sequence, can monitor for colour and faults on the printed sheets, can recall settings from previous jobs and generally head towards lights out or hands off printing. 

Digital job sheets and scheduling remove operator intervention in the flow of work with work being batched, perhaps by the chosen paper type or format to minimise changes at the feeder end, perhaps by TAC to minimise blanket washing or the need to strip down ink rollers when printing a special colour.

This is the big change with on press automation. When press automation first emerged it was a means to set ink keys or for plate changing. Automation was at the service of the press operator and the press responded to the minder’s decision. Now the on press automation tells the press operator what to do at each stage. The decisions are taken by the system’s brain.