By Cassandra Balentine
Part 1 of 2
Vision/inspection systems ensure accuracy throughout the print manufacturing process. As evolving customer demands and the continued adoption of digital print bring shorter runs and greater variability, these systems become increasingly important as manual methods can’t keep pace.
“Print and packaging convey information, and it’s important that the information is accurate and legible. Both play a part with respect to perceived product quality. And while presentation is important to consumers, it is equally important to companies who have spent millions on their branding effort. Incorrect or out-of-registration color, fading, and other issues reflect poorly on the manufacturer, and consumers will choose a more professional finish as a result. In addition, recalls and reprints can be quite costly,” shares Dale Deering, director, market development, Teledyne DALSA.
Elements commonly inspected during the printing process include graphics, content and text, color, variable data readability, and embellishments like hot or cold foil applications, explain Benedict Fiedler, product manager and Nico Hagemann, product management director, ProofRunner Sheetfed, EyeC.
Vision/inspection systems detect print quality defects like splashes, color deviations, nozzle streaks, mottling, branding, and smears. They also perform checks on color tolerance, pattern matching, barcode readability, white space verification, voids, and jet-outs.
Further, select print inspection systems employ optical character recognition (OCR), barcode, or other recognition for safety and security information. “This ensures the correct information and legibility for automated handling,” offers Deering.
At the finishing end, inspection systems can perform sheet and set-level integrity checking for booklets, verify the order of signatures during folding, and cover to book matching, adds Yashashree Potdar, workflow solutions analyst, Standard Finishing Systems.
Digital Production Lines
Inspection/verification is essential in digital or hybrid print workflows, where variability is utilized and the output is sensitive.
“Data verification is a serious consideration when digital print is part of a print solution,” says John Cusack, business development, Baldwin Vision Systems. He believes that in hybrid workflows, the digital element is often introduced specifically for variable data elements like serialization or customization and personalization.
“Custom/variable elements are sensitive and must be correct,” he stresses. “This level of verification cannot be achieved manually using sampling inspection tools, it must be done with 100 percent inspection that also supports variable content streaming.”
“Vision/inspection systems are integral for print providers in any vertical, particularly in this era of high-speed production and short-run applications,” comments Potdar.
Extremely versatile, inspection systems are placed on printing presses, sheet-feeders, saddle stitchers, perfect binders, paper folders, and mail inserters to identify production errors in real time.
Inspection systems also perform verification of material imprinted with virtually any standard symbology, including 1D and 2D code, OCR characters, MICR, addresses, or even optical recognition markings at the click of a mouse or via touchscreen, adds Potdar.
One area of where inspection is especially critical is pharmaceuticals. Deering points out that errors like missing directions, wrong dosage, or time interval instructions represent a significant cause of morbidity, mortality, and expense.
Even when digital print technology is used to print fixed data, there is a strong need to monitor and scrutinize the process. Cusack says digital print technology is in constant flux as the technology is advancing at a tremendous pace. “The consequence of this pace is that often digital print is prone to errors and failures such as jet outs and misaligned printheads. To safeguard against these defects, it is required to check the print engine relatively frequently—once per shift or even at the start of every job. This is usually done by printing test patterns and then manually inspecting the resulting print sample. Again, 100 percent inspection systems can automate these periodic checks by scanning the resulting print samples at up to 600 dpi and digitally comparing them to the digital reference. This ensures the digital press is printing optimally,” shares Cusack.
Along with quality is consistency. Fiedler and Hagemann believe that the most important goal of inspection systems is to ensure consistency. Even in digital printing, print quality issues are still recurring that might not be accepted by customers.
Another significant aspect is time. “Manual practices typically take longer, are more cost intensive, and don’t provide consistent and reproducible results. For certain applications—like variable data—a manual verification process on a larger scale isn’t even possible. Furthermore, manual practices do not scale efficiently with the significantly increasing number of different artworks/products in combination with shorter print runs. Additionally, there are more jobs and order changes that must be completed in a shorter time. Therefore, the implementation of an inspection system is necessary as it helps to improve the production processes and reduce overall cost in the long term,” comment Fiedler and Hagemann.
In addition to accuracy and improved turnaround time, waste is another area where inspection systems offer relief.
Digital printing offers the advantage of reduced/non-existent makeready, and the immediate identification of quality issues that could result in significant material and cost savings, especially when viewed over a longer time period, say Fiedler and Hagemann.
“When used effectively, today’s vision/inspection systems can prevent waste by identifying defects early in the production process. Some systems can even automatically pause production for extreme defects,” points out Potdar.
Print control is an answer to questions, like how can one deliver printed quality on demand, and how to avoid waste. “Here inspection offers a solution for 100 percent quality control. In addition, new services that include artificial intelligence or condition monitoring will contribute to quality analysis tremendously. Customer case studies show how the integration of 100 percent print inspection into the digital workflow succeeds. All the efforts pay off for the printer, as the advantages are obvious—managing the waste of material in an efficient and reliable way within the digital workflow,” adds Lucia Dauer, product manager, print inspection, ISRA VISION GmbH.
Manufacturers experience many benefits associated with the latest advancements in print inspection/verification systems, particularly around automation.
“Almost all volume printing processes involve rapid movement of printed materials, which makes high-resolution, high-speed line scan imaging a natural choice to detect print abnormalities or blemishes,” comments Deering.
Line scans also allow for more uniform illumination and continuous imaging without overlap or gaps, even when presses slow or stop for maintenance. “In addition to traditional print on paper, line scan cameras can inspect a variety of substrates, including metallic foils, plastic, glossy, transparent, or matte surfaces, all of which complicate inspection processes. High-value printing may also involve embossment. The system imaging performance must be able to handle a variety of setups,” adds Deering.
Press manufacturers are looking for ways to improve the efficiency of their offerings and inspection systems are able to help. “Take the pressure and register settings in CI-Flexo presses for example,” offers Cusack. “These are areas not typically thought of for 100 percent inspection or web viewers but working with the OEM it has been possible to implement a workflow where the inspection system can analyze a series of images printed by the press and select the optimal example to tell the press it has achieved correct pressure. Then, the web viewer can be instructed to find the register marks and calculate the X/Y corrections needed to place all colors into register,” he explains.
OEMs have also benefited from verification capabilities in digital applications where the press performance needs to be routinely checked and corrected as needed, adds Cusack.
Fiedler and Hagemann explain that application and service engineers help integrate its inspection systems into the production processes, as well as support and maintain them from the installation throughout the complete product lifecycle.
Inspection and verification systems have a range of uses within print environments. Inspection systems are able to flag defects and color issues in real time to reduce waste and the need for overprints. They can also ensure accuracy of information and prevent mismatches from leaving the premises.
“In general, all digital print for packaging benefits from the print inspection, such as digital print on foil, in every packaging segment where quality control and waste management is a topic,” comments Dauer.
“Print providers who produce commercial publications, direct mail, food packaging, newspapers, pharmaceuticals, transactional mail, tickets, or any other application that requires variable data and precise information can benefit from inspection systems,” adds Potdar. She says these systems can identify printing errors in real-time to prevent costly re-work, even on high-speed presses, and generate a variety of production reports for compliance.
As opportunities emerge in the corrugated print space, new challenges arise. “Brand owners expect high-quality output and develop new applications to create a difference for the end users like customized boxes, which deliver new unboxing experiences. Still the need for accuracy and cost control,” explains Dauer.
With the right vision system, print providers are able to achieve improved outgoing quality and ensure retained business as well as improved internal efficiency.
Cusack says that while many of its customers traditionally focused on outgoing quality, they are noticing its technology placed upstream in the printing process. “When on press, our vision technology can provide real-time performance and show specific defects as they occur. With this feedback, printers can now react to these issues to minimize their extent, thus lowering the total number of defects/waste generated. This allows printers to improve their bottom line while retaining that high level of outgoing quality.”
He says it also answers questions like why press three runs better than press four, or why there are more issues with a particular job, and pick up on changes like defect rates going up right around the time when it might have switched ink suppliers.
Moving from Manual
While manual processes might do the job, there is a point when it starts to impede productivity and profitability. It is important to consider that all environments are unique and proper programming is critical.
“It’s not a question anymore whether an inspection system should be considered—it’s more of a necessity. More printers must rely on inspection systems to stay competitive in most markets. This is especially important to qualify as a supplier for pharmaceutical customers and brand owners as specific quality measurements must be fulfilled by printing companies. This is exactly where inspection systems come into play—they help perform efficient and dependable quality checks with a strong emphasis on reliability, speed, and ease of use,” share Fiedler and Hagemann.
Different segments are at varying stages of this technology adoption. “Printers using digital processes tend to be ahead of the adoption curve. They inherently understand these technical products and the conversation is usually quite easy,” comments Cusack.
Other segments that verification and inspection systems play in vary widely in terms of adoption. For example, Cusack says labels and flexible packaging in general understand and heavily use the technology while corrugated print is possibly ten years behind.
Even within a segment there are tiers of quality that drive decisions. “If we take labels for example, it can be stratified into pharma-grade, premium labels and standard labels. Premium label printers are heavy users of inspection/verification products with pharma printers also using many of the very high-end software features of these inspection products to check things like color, code verification, and variable data. At the other end, standard label printers often prefer to use web viewers as a good enough solution that is more price appropriate for the lower value/margin product they print,” shares Cusack.
Dauer feels that inspection systems should always be considered during the printing process. “Inspection systems release the operator from manual processes that can only be done in a bullet point manner. Print inspection systems allow for a continuous, 100 percent defect inspection.”
It is important to note that inspection systems are not universal. Implementation largely depends on the environment. “Inspection systems are not one-size-fits-all. They must be properly programmed to meet the specifications and needs of each specific print provider. It depends upon the type of application and production volume. Certain applications require set level integrity and production reporting, while others may not require production reports for audits. Static jobs will have different requirements than variable data printing. In any case, shops should explore inspection systems early in the procurement process,” shares Potdar.
Cusack doesn’t think any modern printing process should be without automated inspection/verification. “There are lots of reasons for this listed previously, but one I did not mention is competitive advantage. I see this dynamic happen quite a lot where a printer leverages its use of this technology to secure new contracts.”
He says this also works in reverse where brand owners put pressure on printers to implement this technology, or they will go elsewhere. “These are some of the commercial factors,” he admits.
Within any print process, inspection and verification systems catch errors before they become a bigger issue. From quality and consistency to data accuracy and regulation, these tools are increasingly essential to digital and hybrid print environments where variability, complexity, and shorter turnaround expectations take center stage.
“Content verification and documentation for variable data printing, increased production speed, and the possibility to get live feedback of the print quality to find the sweet-spot for maximum productivity, all speak to the importance of inspection systems in production lines,” add Fiedler and Hagemann.
May2022, DPS Magazine