by Dan Desmond, Standard Finishing Systems
Up until a few years ago, those of us in the print finishing industry only recognized inspection systems as being applicable to the mailing segment of the marketplace. Nowadays, we find camera inspection systems on print lines, sheetfeeders, saddlestitchers, perfect binders, paper folders, casing-in machines and the list goes on. The use of camera technology over reader technology has made much of this possible on almost any type of equipment and has allowed these systems to perform verification of materials imprinted with virtually any standard symbology.
Within any camera-based integrity system, the number of and relative position of the camera(s) within the production device will dictate the system’s functionality. That being said, it’s really not the cameras that provide inspection; it’s the software. The cameras merely capture the image for the software and then the programming takes over.
Web Inspection Systems
In a web inspection device, a line scan camera typically is used to verify integrity of each page on a printed roll. When placed on the web (at least one per side), these line scan cameras function more like movie cameras, taking continuous images as the paper is printed. Marks on the web are read by OMR detectors, indicating the top or bottom of each sheet so that the software can display “pages” uniquely and create stopping and starting points for comparative analysis.
Web inspection system designs vary predominately by the number of cameras required to read the full web front-to-back, the type of feed-through of the web (passive or controlling speed) and of course, the user interface and software. These web inspection devices can perform many quality and integrity checks simultaneously, including barcode and MICR grading, color tolerance, pattern matching, white space verification, ink or toner spills, voids, jet-outs and more.
Ultimately, the job of the web inspection system is to read each of the pages generated for specific areas of quality interest, as defined by the operator within the given software limitations, and perform any one of the following actions at minimum:
- Stop the printer line to a soft shutdown.
- Alert the operator by way of warning lights that errors are present or have exceeded their threshold.
- Divert error-laden pages into the waste bin.
- Capture data for sheets/packages with quality flaws.
Either built-in or through separately purchased software packages, the best web inspection systems are going to collect the data of passed or failed documents. Other options may include integration with ADF (Automated Document Factory) workflows and/or communication to and from inspection-equipped finishing devices downstream to alert the machines of inferior quality packages that should not be processed or diverted.
Within this finishing device, an inspection camera could be placed at several different positions to verify integrity during booklet production. Small cameras are utilized to read a given area of about 2″ x 2″ on each sheet as it enters the accumulator. This technology works with sheet feeders for pre-collated digital output, as well as collating towers, provided that the sheets are fed separately or shingled in their delivery to the accumulator.
First, the camera looks for a coding regimen that would indicate the total sheets to be found in the set, which sheet of the set it is and its unique package identifier to indicate that they all belong to the same set. As the predetermined criteria are reached within the software, the set is passed along as a “package” to the next station. If the established criteria are not met, that package either is stopped or diverted based on the saddlestitcher’s functionality. Either way, that package is marked as invalid and should be destroyed by the operator.
This coding regimen usually is accomplished within a string of letters or numbers in OCR-A or -B font, with a universal 1D linear bar code or 2D data matrix bar code. Within the software, the operator defines what characters within the string signify a specific property.
Additional cameras can be placed ahead of reject trays – if the saddlestitcher has them – or at the output end of the trimmer for final production verification.
Perfect Binding Systems
On a perfect binder, the base system consists of two cameras. The first camera reads the code on the cover; the second camera reads the code on the book block. The programming defined in the software will determine if the cover is a correct match for that specific book block and enable the binder to complete the binding process. If there is no cover match, the binder is inhibited from cycling until the error is corrected.
The positioning of the cameras and the reading areas also can guarantee that the cover has been loaded in the correct orientation and that the book block has been placed into the clamp properly. This capability has far-reaching benefits within a plant when using the vision system for even longer-run static work (versus just personalized and regulated work). By identifying improperly assembled books, the system virtually can eliminate materials waste after makeready, leading to productivity improvements and increased customer satisfaction. Additional cameras can be added to verify that the assembled book has exited the binder or three-knife trimmer for final product verification of the complete process.
Camera inspection systems typically are used at two or three positions within a production-level inserter. The systems can be used at the primary feeder for static or variable page sets to ensure that all sheets of a set are there and in order. If the inserter is capable of intelligent inserting, this is the location where the code would be read to tell the inserter which of the insert pockets should feed to add specific inserts related to the primary document or recipient.
If the inserting job requires that the primary document be matched with recipient specific materials from that side pocket, then a camera would be added to the transport or insert pocket so as to read the code embedded on that piece to connect it to the primary document.
A final inspection camera typically is used in inserter applications to verify that each envelope is filled with the recipients’ documents. This viewing is done through a window envelope.
Camera Systems Offer Unique Benefits
One of the big advantages camera systems offer over specific bar code reading systems is that they are adaptable as to the type of symbology they are going to be reading. Camera systems read virtually any standardized symbology, whereas 1D readers only can read 1D code, 2D readers only can read 2D code and so on. Camera systems also provide the ability to read OCR characters, MICR, addresses, Blob, images (pattern match) or even OMR markings at the click of a mouse.
The unique versatility is brought on by the software and programming of the PCs or the cameras themselves. Camera systems that utilize a separate and independent light source can be configured to read any of the standard symbology and the OCR, MICR, addresses and images printed with invisible ink.
Another big advantage for camera-based systems is that they utilize a PC to do the analysis and control much of the finishing device. The systems can be integrated into the network workflow, which can provide several production management benefits. With this type of PC utilization, operators can be informed quickly and in great detail as to what the failed integrity event was that just occurred and look back at and review the images captured from that event. A system built with simple barcode readers typically does not capture images and does little, if any, reporting for the operator.
The PC that is an integral part of a camera system can compare the results against an imported data file and update that file with individual sheet or package status so as to provide the following:
- Full audit trail on book or booklet assembly completion for regulatory purposes,
- A document reprint report,
- Production data for SLA performance validation,
- Production data for measuring operator performance and
- Production data for equipment performance.
Some of the more advanced systems can provide for emailing daily production reports or enabling management to review real-time production results through secure web connections. One even has an iPhone application that can let operators view production data anywhere and anytime.
Dan Desmond is the business manager for Inspection Systems at Standard Finishing Systems. In this position, Desmond works with customers and prospects to insure that production runs operate at maximum efficiency while delivering 100-percent document integrity. Standard Finishing Systems is based in Andover, MA and celebrated 100 Years of Finishing Strong in 2010. A leading supplier of print finishing systems, paper handling equipment, mailroom and reprographic products, Standard utilizes a network of independent dealers and a direct sales force in the United States and Canada. For more information, call 877.404.4460 or visit the Standard website at www.standardfinishing.com.