Inline Versus Offline Inspection
Consumers are probably as smart as you think they are, and when it comes down to one vendor’s package versus another’s, they notice everything. They’ll notice print and graphics on the package that are out of registration, and they’ll definitely notice when the bar code isn’t printed correctly as they wait at the checkout for an item to scan properly. You’ll see it in your bottom line if the vendors to whom you print packaging aren’t completely happy with the end result, especially if what you printed doesn’t match what they approved at the tail end of press qualification. Today’s web inspection systems have increased in sophistication to address the very specialized needs of several packaging categories, from food to pharmaceutical. There are various criteria converters must consider when selecting a web inspection system, beginning with which type to specify—inline, offline, or both.
Inline vs. offline inspection systems
Inline inspection systems are used while printing on a press to show issues with registration , streaking, or voids so they can be corrected quickly and have minimal impact on the job, according to Scott Durfee, district manager for Fife Corp. These systems look for printing defects and continuous style problems. Offline inspection is suitable for a slitter/rewinder where the converter slits a printed roll down to the required size. “[Operators] will use this system to detect a hickey, spot, or some other intermittent style problem,” says Durfee. “Once it’s detected, they’ll stop the machine, flag the issue, or splice it out.”
Gal Shamri, vice president of marketing, AVT, says that on-press automatic inspection is used mainly for process control, meaning to assist operators controlling quality during printing in order to reduce material waste. As the rewinder is typically the last stage before shipment, the printer’s main target when installing an AIS (automatic inspection system) is to perform quality assurance, meaning to detect all waste defects so they can be removed before shipment to customers.