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.

Saddlestitching/Bookletmaking Systems

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.

Mail Inserters

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.

by: Dan Maurer, Rob Kuehl and Steven Calov, Heidelberg

It’s been said the cost to retain a customer is a lot less than the cost to get a customer back. As the print industry pushes into the era of lean manufacturing and quality control, both offset and digital presses have benefited from advances in integrated color management, inline image quality inspection and efficiency optimization. But quality is only good if the finished product shipped meets your customers’ expectations. Our hyper-competitive environment leaves little room for error, and the cost of a returned job may mean more than just the cost of a reprint – it may mean losing a customer.

Quality measures in the bindery are increasingly a focus for printers, accompanying the speed and efficiency gains of the latest automated equipment. Perhaps this is part of the reason why NAPL’s 2009 study of the top expected capital investments of commercial printers ranked finishing investments as the number two priority. Not only can these systems prevent job returns, but a sales team also can use this capability to sell jobs at higher profits. Print buyers’ marketing and procurement departments don’t want to risk the embarrassment of a defective product on their end and are willing to pay to make sure it doesn’t happen.

Invest in Quality Equipment

Quality inspection in finishing takes on several dimensions. Sensing technologies integrated into software systems on the latest machines can verify that every product is produced as expected. Before even checking the final quality output, the first and least expensive improvement is simply making sure that all of the high-quality finishing equipment is maintained to the best standards in order to produce consistent superior results. How many people thought they were getting a deal on a low-cost alternative, only to find that getting repeatable quality off the machine and getting the makeready set up to achieve good results proved too time consuming? The quality of the knife in a cutter, or a stitcher’s trimmer, or the fold roller condition can compromise a job’s profit potential. Even the accuracy of a cutter’s backgauge can have a profound affect on cutting quality, including the ability to tilt the back gauge for image-to-sheet skew. Implementing a quality control program with mandatory maintenance intervals also can yield major cost savings.

To illustrate the point, let’s take a closer look at guillotine cutters. Once upon a time, these were among the simplest machines to be found in a printing plant. Today, however, cutter manufacturers have reinvented cutting technology in light of automation and digital workflow. Examples would include quality control inspection with minimal paper waste through software programming, which enables jobs to be assembled automatically and added to the queue faster by storing instantly retrievable cutting programs. The operator not only saves considerable downtime by eliminating the need to enter job data manually to configure the cutter, but also avoids data-entry errors that could miscue the cut and spoil the product. A consistent cutting process minimizes errors, and builds confidence and coherence throughout the cutting and finishing process.

By the same token, fully automated cutters reduce the production time with fewer workers and turn the operator into a supervisor as the machine takes over most of the cutting functions. This eliminates bending or lifting, as well as reduces time and material waste, delivering top quality through mechanized routine sequences. Advanced software can tie into MIS systems to convey vital setup and job costing information to make sure profitability remains on track.

Simplify Makeready Processes

Another quality control improvement area can come from ensuring that makeready is done efficiently, keeping operators from using short cuts to get to production more quickly by sacrificing quality. Automation from prepress sent directly by JDF to a cutter, folder or stitcher helps reduce both makeready time and operator fatigue. While there’s always a risk of prepress making an error in the file, the time required to verify a job set up is often a lot less than starting from scratch.

The second part of automation is saving job parameters in the machine, so that a second or third shift operator can recall the job, making sure the output is consistent from first to last piece, as well as for repeat jobs. The condition of the equipment and its built-in design performance is also key. Lastly, consider how a relatively low-cost but high-gain improvement can be achieved by using the appropriate delivery system. Non-marking deliveries on folders are an example, and banding solutions can make sure that signatures are not damaged during material handling to a stitcher or binder.

Take Advantage of Technology

If these first two measures represent proactive quality improvements, what about closed-loop quality verification? The latest finishing equipment includes advanced sensing technologies that are integrated into the machine’s software to monitor each piece so that it’s produced as intended. These systems range from relatively simple to an extensive integration of technology. Examples include stitchers and perfect binders, and run the gamut from cameras and bar code readers to oblique and long book error monitoring, missing stitch detection and trimming quality monitoring.

Even better are systems that can identify a defective book, eject the defect and continue production without stopping. The very latest perfect binding technology includes glue thickness sensing so that each book achieves the best bind. Similarly, folding carton folder-gluers now have integrated carton ejection for eliminating cartons that are badly glued or with image defects. This capability is critical in both pharmaceutical and cosmetic box applications.

From there, we move into more complex camera inspection systems integrated into all areas of finishing. Label manufacturing now includes cutting systems that use cameras to make sure labels aren’t intermixed. We don’t want carrots labeled as peas, right? Folders can integrate cameras and vacuum mail tables to pick and place samples and variable products onto mail pieces, while also verifying the correct product matching and location quality of the glued product. For several years now, cameras have been used to provide the customer with verification that every piece in a given job was produced and labeled accurately.

Some people in our industry long for the “good old days” and bemoan how stressful the competition in our industry has become. That’s a shame, because it’s such an exciting time to embrace technology in all areas, from web-to- print to MIS to the integration of lean manufacturing practices, together with amazing finishing applications and quality measures. As an equipment manufacturer, we find that the opportunities these advances represent enable us to get closer to our customers, working with them on customized engineering projects that help solve problems and drive profitability. The key is to think outside of the box. Talk to your customers about the cost of quality, and think of your equipment provider not as the guy you call to replace that aging cutter or folder, but as a business partner you call on when you’re scratching your head over a complex finishing job, a material flow bottleneck, lean Six Sigma implementation and the integration of tools to raise the level of your quality and profitability.

Heidelberg develops and manufactures precision printing presses, equipment for plate imaging and postpress finishing, as well as digital inkjet systems for packaging manufacturers. For more information, visit www.us.heidelberg.com.

by: By Ken Troemel, Andy Grzesik, and Mark Blitshteyn, MKS Ion Industrial

The newest saddlestitchers and perfect binding machines are capable of high production speeds. Yet a common problem faced in the bindery department is not being able to run their lines at the rated speed.

Incline Stack Tacking Challenges

One of the bottlenecks in the bindery is compensating stackers. There, the magazines are conveyed by the belts up the stacker and dropped into the compensator where they are stacked to varying heights to meet postal routing specifications.

To keep up with the high speed of upstream equipment, the magazines have to be pushed out of the compensator quickly. This process causes some magazines and catalogs to shift, resulting in uneven stacks of shrink-wrapped books. The USPS can reject the defective stacks, which forces the bindery to separate and re-run the magazines off-line. While many outstanding innovations have been introduced to assemble neat square stacks, when the stack is pushed out to be transported through the shrink wrap tunnel or other packaging, the mechanical forces that kept the stack straight are no longer present.

Oval strappers are sometimes utilized after the stack is pushed out of the stacker. The strapper has become less desirable as the post office needs to route individual magazines to their destinations. Additional detractors are strapper maintenance and downtime.

Magazines with UV-coated covers, either perfect bound or saddlestitched, have very glossy slippery surfaces, which make them vulnerable to shifting when stacked. High page count saddlestitched magazines create challenges because the spine side is thicker than the open side. This could cause the books to slide over to the open side and potentially shingle as they exit the compensator.

If the stacker does not produce neat, true stacks, either the entire line will have to slow down, regardless of faster bindery equipment upstream, or operators will need to be added at the output of the line to manually straighten the stacks.

Electrostatic Stack-Tacking

What is difficult to accomplish by mechanical means could be done with electrostatics. Electrostatic forces of attraction can hold magazines in the stack, preserving the perfect shape achieved by advanced compensating stackers.

There are two practical electrostatic system configurations that could be employed in the stackers. One arrangement is known as cross-tacking. It employs three charging bars inside a compensating stacker. When a stack is assembled, two separate plates hold the stack from each side and the third plate comes down and squeezes the top of the stack. The charging bars in each plate are energized; the electrostatic field and ionization tack the magazines together and keep them from shifting. Cross-tacking is the only electrostatic option for magazines conveyed by the belts up the stacker in a shingled stream.

Cross-tacking systems cannot be retrofit in existing stackers; they have to be designed in by the manufacturer of the stacker. The cross-tacking systems are complex and expensive, requiring three charging bars, special insulating plates to hold charging bars in place, and other special design features. Since cross-tacking systems usually come installed and properly engineered, binders do not need to do much to have them provide solid stacks.

Compensating stackers not designed for cross-tacking systems and which receive the magazines singly, can be retrofit with an electrostatic system in the incline feeder section. These are known as incline-tacking systems. Since different types of equipment can be utilized for incline electrostatic tacking systems, a printer needs to know how the system functions, how to select the charging equipment, and how to maintain it.

Electrostatic Tacking in the Incline Feeder

Incline tacking systems typically use a pair of charging bars, one placed above the magazine’s path into the stacker, the other below. The ionizing pin electrodes of the two bars are generally aligned against each other. The positive polarity voltage is applied to one bar and the negative to the other from a pair of high-voltage charging generators or from a single generator with dual-polarity outputs. The distance between the bars should generally be 2″ or less. The smaller the bar gap, the lower the voltage required to generate a sufficient tacking effect.

When the bars are energized with no magazines in the incline feeder, the opposite-polarity air ions produced by the opposed bars will stream toward each other, completing the electrical circuit. When magazines are being fed up the incline, they interrupt the flow of ions between the bars. The ions deposit on both sides of the magazines, charging each surface opposite in polarity, as shown in Figure 1 (page 22). Magazines carry these charges away, in the form of a “convection” electrical current, again completing the electrical circuit.

The immediate effect of the charging is that the magazines “tighten up” and are held closed shut by the electrostatic force between the front and back cover pages. The air gets squeezed out from between the pages. While that certainly contributes to forming a neat integral stack, it is the secondary effect that is most important. When a charged magazine is dropped into the stacker, it lands with its back cover on the front cover of the previous magazine. Opposing charges on the back and cover pages of the two magazines create an attraction between them, causing the books to adhere to each other, as shown in Figure 2 (above). That attraction will keep the magazines from shifting when the stack is in motion.

Selecting and Using Electrostatic Systems in the Incline Feeders

Step 1. Install nonconductive belts to avoid arcing from the bars to the belts.

Step 2. Install charging bars with the effective lengths 1″ shorter than the most common height of the magazines you run on the stacker.

The ions from the correctly sized bars deposit on both sides of the book, charging its surfaces, as shown in Figure 3 (page 26), without the problematic discharge around the side edges of the magazines.

IMPORTANT: If the bars are too long, extending beyond the edges of the magazine, a high portion of the charging current is flowing through the air between the bars at both ends. The ends of the bar could overheat, causing the bars to burn out.

Step 3. Adjust the output of the charging generator to achieve optimal tacking confirmed by the square bundles coming out of the shrink-wrap tunnel. Notice the charging current value, because the electrostatic pinning force is determined primarily by the value of the charging current, not the voltage.

Because the magazine surface can carry only a limited amount of charge, the total current between the bars drops down to one-third of the current between the unobstructed bars (the actual value depends on the magazine’s size and thickness, and the type of paper, the coating, and the ink). For example, if the current between two unobstructed charging bars is 1 milliampere, the current would drop to 0.3-0.4 milliampere when a magazine is passing between the bars.

Such current fluctuations repeat with the current going up after the magazine passes through, and going down after the next book comes in between the bars. While it’s possible to see some fluctuations in the current meter, charging generators are not capable of showing such fast changes, as the current goes up, down and up again in 0.1 second’s time on the fastest stackers.

The most effective operation can be obtained with charging generators featuring a constant current (CC) mode. In the constant current mode, the generator automatically adjusts the voltage to maintain the preset current. In this mode, the system maintains stable and strong pinning power adjusting output down when there is open space between the magazines, and also offsetting changes in the line speeds, ambient conditions, or paper dust buildup on the ionizing electrodes.

IMPORTANT: Effective control of the pinning process is possible only when the bars do not extend beyond the edges of the magazines – see Step 2. With long bars, the current flowing directly between the bars is not contributing to the tacking process. Under such conditions the monitored current value is nearly meaningless.

Step 4. Keep the ionizing electrodes sharp.

Electrodes of the positive charging bars wear out 3-4 times faster than the electrodes of the negative bars. There are three methods for keeping electrodes sharp:

• Use tungsten pin electrodes.
• Use replaceable pin electrodes.
• Increase the number of pin electrodes to spread the current over a larger number of electrodes and reduce the current density for each electrode.

Step 5. Keep the ionizing electrodes clean.

Paper dust should not be allowed to build up or cover the electrodes. Clean the charging bars often. Use a metal brush to scrub through the electrode channel during makeready. That especially becomes a problem with overly long bars, because the ends of the bars will be collecting excessive amounts of paper dust falling on the electrodes from the sides of the magazines.

Ken Troemel, Andy Grzesik, and Mark Blitshteyn of MKS Ion Industrial share a two-part series with readers. They explain how to create effective electrostatic solutions for various printing and converting problems. The authors have many years of combined experience in creating effective electrostatic solutions for various printing and converting applications, working for Tantec Inc. and later for MKS Ion Industrial. In 2006, Tantec USA became a part of the Ion Industrial product group formed to service the paper and film converting and plastics industries in 1997. For additional information on MKS Ion Industrial, visit www.mksinst.com/ion-industrial.