Eye On Inspection

The human eye is an amazing organ but sometimes it needs a little help. With press speeds reaching 1,000 fpm, operators would have a hard time catching print blemishes and other defects on the web if it wasn’t for inspection systems.

All inspection machines can help printers save money and to explain the types of inspection systems on the market, packagePRINTING asked industry experts for their input.

Explain the difference between inspection systems available in the package printing marketplace.

• Jim Doerr, president and CEO, TruColor Vision Systems: Currently, the market is filled with inspection options. Features, advantages, and system benefits can be as varied as the amount of capital it requires to invest in inspection technology. Choices include: human eye, rotating mirrors, high-intensity strobes and, of course, machine vision type systems. TruColor Vision Systems now offers a complete range of machine vision-based inspection systems beginning with the basic entry level models, then on to midrange automated models—automated in terms of automatically positioning and moving the inspection camera around the web.

• Nat Stern, CEO and VP, eltromat electronics: There are essentially two types of print inspection systems, 100 percent and samples. Sampled uses an area camera strobe arrangement on a traverse and is capable of very fine inspection. These systems are mainly for preventive control where defects are detected before they become serious. The shortcoming is little chance of finding sporadic defects. One hundred percent systems generally use line cameras and have less sensitivity than sampled systems. They are very good at catching sporadic defects and are usually the choice for inspection rewinds.

• Tim Lydell, CEO, Label Vision Systems: There are several inspection-type systems in the market, from simple sensors to complex wide-web systems that operate at very high speeds. LVS operates in the middle of this range with a print inspection system that has the complexity to provide complete inspection of print quality of static print as well as truly variable print from label-to-label at high speeds. This is the LVS 7000 product. A sensor will look at only one or two areas on a label as it passes the inspection station. It does not have the intelligence to make decisions, only determine if it saw what it expected to see.

• Gal Shamri, VP marketing, Advanced Vision Technology: First, we have to differentiate between a “viewer” and an automatic inspection and defect detection solution. While a simple viewer only views a captured image on a monitor, an automatic inspection system automatically analyzes the image, and detects print defects and quality variations along the production run. This enables operators to perform corrective activities before producing waste and to remove defective material before shipment. Equipped with an area camera, process control systems detect process defects at the earliest stage, enabling the printer to avoid defects before running waste, hence reducing waste material cost. One of the main advantages of the process control platform is its ability to host a variety of added-value modules such as in-line color measurement, register control, pressure control, bar code verification solution, and many others. One hundred percent quality assurance solutions such as the AVT PrintVision/Apollo are typically installed on post-press machines and are based on Line-CCD camera technology. Quality assurance systems detect all defects appearing on the entire repeat 100 percent of the time, assuring waste defects are detected and removed before shipment.

• John Woolley, VP sales and marketing, PC Industries: The typical package printer can inspect either on-press or on an inspection rewinder. Inspection systems installed on an inspection rewinder usually provide 100 percent inspection of the web 100 percent of the time. Digital area scan cameras are superior in these applications because the accuracy of the vision system isn’t affected by speed changes or web guiding issues. Inspection systems installed on a printing press can be one of three types: 1) Basic web viewer without defect detection; 2) 100 percent repeat inspection (or sampling inspection), which uses one camera that will automatically move across the web and provide defect detection; and 3) 100 percent web inspection which uses multiple cameras to provide defect detection on 100 percent of the web.

• Brian Ivens, president, Arpeco: There are two primary types of cameras used to acquire images in a vision inspection system. The array-based camera takes a snap-shot of the web and then sends the entire data to be processed in real time. With this type of system, maximum web speed can be limited due to the amount of image data to be processed based on camera resolution, and the size and type of defects to be detected. Also, web flutter and illumination can be issues as the entire image must be presented flat to the camera and lighted uniformly for image acquisition. This system does have an advantage—during start and stop operations as image capture occurs at intervals.

Line-scanning technologies utilize continuous data acquisition and, until recently, had difficulty with image acquisition when transitioning to and from zero speed. They do have the advantage of being able to wrap idlers to minimize web flutter, require only single-line illumination, and can have larger lateral resolution than array-based systems. Also there is almost no limit to the longitudinal resolution of a line-scanning system.

Inspection Systems

Automatic inspection

AVT’s PrintVision/Jupiter offers a high level of process control and automatic inspection solution for flexible packaging converters. The PrintVision/Jupiter automatically detects process faults, reduces the cost of quality by tracing defects early in the process, eliminating print waste and enhancing press productivity and utilization.—Advanced Vision Technology, www.avt-inc.com

Inspection/rewinder for security

Arpeco’s INSPECTOR® is a high-speed inspection/rewinder for security verification of pharmaceutical roll labels featuring an electronic option package specifically designed for the label and pharmaceutical industries. Packages can include bar code scanning, label plus length counting with security window error feature, missing label, matrix and splice detection, as well as print quality inspection using stroboscope or vision systems. —Arpeco, www.arpeco.com

Inspection for narrow webs

BST Pro Mark’s 100 percent inspection system, Shark™, is for narrow-web label presses and rewinders. Shark’s defect management software package was designed to speed up the process by making it easier to evaluate defects the system has identified, and to quickly and efficently take appropriate action. Shark has an intuitive operative interface for greater ease of use, as well as a lighting system that guarantees consistent lighting. Shark will perform 100 percent inspection of webs to 500 mm.—BST Pro Mark, www.bstpromark.com

Systems for pre-, on-, and post-press

Image Inspector:2, from the NYSCAN product line of Erhardt + Leimer, offers an accurate, easy-to-use tool to verify makeready against the client-approved electronic artwork. At the end of makeready, the Web Inspector:2 camera on the press captures a reference image, which can be immediately compared to the approved PDF artwork by Image Inspector:2. Acceptance parameters established by the operator for each custom job are used to control the comparison. Erhardt + Leimer offers the Web:Inspector:2 for on-press processes and the Roll:Scheduler for finishing processes.—
Erhardt + Leimer,
www.erhardt-leimer.com

High-speed inspection

The Eltromat wv_3000 offers high-speed inspection for gravure, flexo, offset, and screen printing applications. The system features a high-resolution 3-chip camera that allows fast and precise image reproduction of the highest possible quality. The wv_3000 is easy to operate with a touch_screen, which has a well structured menu for entering, storing, recalling, and modifying information.—eltromat electronics, www.eltro.com

Inspection for quality

Fife’s compact, all-in-one web viewer help soperators monitor print quality on fast-moving webs. InPrint Video Inspection systems integrate the camera, control panel, and microprocessor into a single, compact, industrial grade housing. There are fewer components to install, and all cables have a connection on both ends to simplify wiring. 24x zoom and advanced features allow for prompt detection of the smallest variations in print or register settings, so they can be corrected before they appear on the final product.—Fife, www.fife.com

Operator-friendly system

The LVS® 7000 by Label Vision Systems is easy to use. Once set up of a job is initially completed, it only needs to be called up from a stored file for future runs of that job. Events inspected can be reported in detail or recorded in a summary format. Other key benefits include unlimited lanes across a web on a single system, intuitive and quick user set ups that can be stored and recalled, bar code to human readable comparison and match, and label counting.—Label Vision Systems, www.lvs-inc.com

Productive inspection system

The Mark Andy VSR300 is a productive finishing system. It is a simple, easy-to-operate, inspection rewinder for slitting and finishing of printed pressure-sensitive rolls. The wide-open concept allows the operator to easily see both the unwind and rewind rolls while inspecting. Standard features include web widths up to 16.75˝ and speeds up to 900 fpm.—Mark Andy, www.markandy.com

Quality inspection rewinder

Rotoflex’ VLI eDRIVE Series inspection rewinder is easy to operate. It offers consistent performance, low maintenance, lower tension/higher speeds, easy job set up and operation, and an electronically synchronized motor-driven system. The system inspects webs 10.25˝-28˝ wide, and runs at speeds to 850 fpm. The VLI eDrive has a touch-screen operator interface and current Feedback-Auto Tension Control on unwind/rewind.—Rotoflex International, www.rotoflex.com

Automatic web inspection

TruColor Vision Systems’ TruRegister can be used with the TG 4000 Series for automatic register presetting in CI presses. Using special printed register targets with each job, coupled with a data communication link to the press, TruRegister automatically sets the colors into the desired registration. It supports jobs up to 12 colors, and automatically positions to register marks with continual auto tracking for web skew.—TruColor Vision Systems, www.tcvs.com n