Esko and Bobst collaborate to develop smartGravure

Esko and Bobst have partnered to develop smartGravure for the technology's pre-press and in-line color reading elements. The system can more than halve the color matching time, reduce downtime by 70 percent and supercharge efficiency for gravure printers.
 
The system enables gravure printers to benefit from a fully digitalized workflow, optimally producing enhanced and consistent quality, minimizing substrate and ink waste, and maximizing efficiency across the print process.
 
Davide Rossello, Bobst competence center manager and R&D process manager, gravure, said that the project began in 2019 when Esko was undertaking exciting work in Extended Color Gamut printing in prepress. 'In Bobst Italy, we always manufacture gravure,' he said. 'Ink control is the final step on this journey – but while this process began in prepress, it has now moved to the end of the printing process.
 
'We were looking to introduce something new. Gravure is a stable technology with fewer variables compared to others. It is always the reference point when comparing print quality results, and our focus is on improving productivity, management, and efficiency.'
 
Rossello explained that the fragmentation of orders, with the varying number of jobs and changeovers, meant that gravure printers traditionally faced challenges when changing the cylinder for each color. The color adjustment process required much time to achieve the highest quality.
 
'As Bobst did not have a color matching tool, it was left in the hands of the customer,' Rossello said. 'We decided to look at the setup time and tried to simplify all our customers’ machines and digitalize the process’. When printing in ECG, we knew we needed the optimal technology to check the print register so as to simplify color adjustment. We needed first-class prepress color software and faced the challenge of combining it in the machine to fix the color properly. This is where Esko enters the game.'
 
David Naisby, business development director at Esko, explained that the key technology in developing a smart system was its AVT SpectraLab system—the market-leading technology first launched in 2012, of which SpectraLab XF is the third and latest generation.
 
'This ISO-certified measurement device took many years to refine, and today we are proud to be able to measure both media strip and within the printed image during press start-up and the printing process,' said Naisby. 'This is an enabling technology for any press manufacturer to take advantage of. Bobst understood how they could turn this into an advantage for their customers to improve productivity, reduce environmental impact and ultimately increase profit.'
 
The team at Bobst evaluated several technologies and determined that Esko had the complete technology to address their technological needs. 'Working together, the two companies’ R&D departments developed software that simplifies the operator interaction with the AVT SpectraLab XF and allows live density and color information to be displayed on the Bobst user interface,' said Naisby. 'Testing during 2022 produced excellent results, and we can now match the readings from the press to the X-Rite eXact Spectrophotometer to be within one Delta E, the industry-accepted tolerances.
 
'With the trend for shorter run lengths, color matching and the associated waste and time creates a major bottleneck which leads to unacceptable costs for the converter,' he said. 'With smartGravure, we have taken a major step forward with this technology.'
 
Bobst’s Rossello added: 'Essentially, Esko gave us the recipe for how to fix the color in the machine digitally. As a result, we now have 100 percent control over what is happening in the press with smartGravure. With this new tool, users can address any misregistration, tone value increase (TVI) differences and color control, all in-line. Delta E tolerances are guaranteed, and it also enables the adjustment of process colors, which we can measure in case of any deviation, effectively closing the loop on color matching in the press itself.
 
'In controlling production, repeatability can be assured as everything is digitalized. The machine is now adjusting to bring everything in-line with the benchmark,' he said. 'This is a new technology that can be implemented in a gravure press to give output for a customer that is fully controlled from the first to the last.'
 
With around 50 percent of time spent on setup and 50 percent on production, the development experts at Esko and Bobst analyzed the data. They determined the bottlenecks in the gravure print process.
 
'We recognized that the customer was spending anywhere from 45 minutes to two hours color matching,' added Rossello. 'Obviously, that’s a significant amount of time to lose. Because we are machine manufacturers, we never looked at the chemical composition of the inks used in spot colors. We have an excellent relationship with Esko, and as we needed a partner from the prepress world, an expert in software, and preferably a technology that integrated with the Esko Automation Engine workflow technology to read composition and color, it made perfect sense to work together.'
 
Esko was a key part of the project from day one. The first fingerprint was printed with an Esko logo. Naisby explained, 'The dream of all converters is to run a press automatically without having to adjust color. With this partnership, we are proud to empower operators to achieve their goals.
 
'The fundamental part of this process is the accurate measurement of color, as everything in the workflow depends upon this,' he said. 'Secondly, the color data workflow has to be simplified. Press operators cannot enter complex target density and color values press-side. The SpectraLab XF is connected to the X-Rite ColorCert product in the Esko S2 cloud technology to achieve this. Specific job color target information is sent to the press, automatically setting up the SpectraLab XF with the correct values for each printing unit.
 
Measuring at high frequency during high production speeds, Esko’s AVT SpectraLab XF ensures perfect color matching and consistency to a brand’s specifications. It also helps reduce waste by alerting operators for color density deviations and assisting them in getting back to needed color tolerances. With Bobst's new color control abilities, this ability is translated into an automated closed-loop color technology.
 
'Our first test was in 2019, and now we have it finally set up on a machine in our competence center,' added Rossello. 'In terms of the difference smartGravure makes, it is simply better. It automatically adjusts the base and color extenders to bring the color to the target density.
 
'In tests, 94.6 percent of the extended color gamut has been achieved using smartGravure, with the lowest still an impressive 89 percent. A range of 89-95 percent is surprisingly high, with only some very specialist colors missing.'
 
'What has taken hours until today can now be significantly reduced to under 20 minutes, depending on the job and colors involved,' said Rossello. 'To replace the cylinder, from the moment the machine stops, it is now just a few mechanical changes, and we don’t have to wash anything. Color adjustment should not be needed for a new job, so we can change the cylinder much faster and be back up and running on the new job in less than 20 minutes.'
 
Naisby said that in terms of actual savings and benefits, the numbers are as impressive as they are staggering. 'The increased efficiency means that idle time is reduced by as much as 70 percent, with what used to take 90 minutes or so reduced to less than half an hour. This creates additional advantages regarding the availability of presses and an overall improved productivity.'
 
To measure color, gravure operators need to print a test run – which involves starting and stopping several times as they achieve color-matching speed, printing around 300-350 meters each time before testing and repeating until the color is perfect. 'That’s a lot of printed material wasted, both in terms of substrate and ink, as well as energy and time used,' said Naisby. 'With smartGravure, this can be achieved with one single stop and start, meaning as much as a 60 percent reduction in materials saved at the changeover.
 
'Not only does this deliver big benefits in terms of material gains, but it also further prevents wastage by enabling print customers to recognize a problem early in the run rather than when the whole reel is complete.'
 
Regarding color quality, Rossello explained that a Pantone validation test returned the first ‘Print totality of colors’ rating ever to be attained by a gravure printer. 'This was in one run, on the RS 6003 press in our competence center, with 2,369 colors, where we achieved a 92.1 percent rating,' he said.
 
'With this new tool developed by Bobst and Esko, gravure printers can enjoy an end-to-end digitalized process – enabling them to meet and exceed the highest industry standards with ease,' concluded Rossello.