Bar code detection

Ensuring the integrity of the bar code is critical to the most basic confidentiality of the packaging printer. Before you purchase the inspection system, you must first understand its real situation. The accuracy of the bar code device and the meaning it contains is often overlooked. In fact, a precise bar code can save the printer and the end user a lot of time and money. Here's a brief introduction to some of the bar code detection. Scanners and Verifiers People sometimes confuse the two, but the difference between them is still huge. The scanner can only extract the data content of the barcode, ignoring some errors caused by the printing. The scanner can only read the barcode data and symbols in a specific way even when testing the barcode quality, even if the data and symbols Unrecognizable, it cannot explain why this is so. The verifier can measure some defects caused by printing and report it in a reasonable way. ANSI-developed bar code rating The bar code product quality can be referenced by the ANSI (American National Standards Committee) barcode quality standards. As early as 1990, ANSI published the X3.182 bar code printing quality standard, which describes the eight parameters that should be measured on the bar code: decoding, minimum reflection coefficient, minimum edge contrast, boundary definition, sign contrast, FM, defects And decoding rate. Each aspect is characterized by A to F levels (A is clearance, F is failure). If any ANSI parameter is unqualified, it means that the entire barcode is not qualified. In order to obtain a formal grade of the UPC symbol, 10 different scan lines are selected from the top to the bottom of the entire barcode for evaluation. For printers, it is not required that a certain hard index must be reached. ANSI's judgment is completed under the judgment of the customer. For the printing industry's customers, the bar code quality level must be 'C' or better. 'Class even better has formed the default profile. The ANSI method has basically been considered as the most effective way to determine the quality of a barcode. In Europe, the European Institute for Standardization (CEN) has also adopted this method, but only slightly modified it according to the specific circumstances. System performance When considering whether to use an online or offline authentication system, you must keep in mind your main purpose. The on-line system performs 100% inspection. Its main advantage is that the problem can be identified and verified before it is wasted. It can also provide various types of printing training tools. Online systems can not only collect and analyze information that indicates pass/fail, but can also use this data to ultimately determine the trend of the improvement process. With this system, you can correlate some of the phenomena that appear on the bar code with problems during the printing process (such as clogging of ink nozzles, excessive head loss, or ribbon wrinkling). When considering the use of a portable or online system, it depends on the specific conditions of the job. Usually, online verification is applicable to short-lived applications or where code information varies. The laser system provides the user with non-contact operation and repeatability without requiring the device to be in direct contact with the print. It can automatically move the laser beam over the code to obtain 10 scan lines. The CCD camera system can detect the entire bar code or only the code part. In addition, regardless of the direction of the bar code, whether it is vertical or horizontal, CCD devices can not constitute an obstacle. The offline verifier (including the handheld type) can obtain more complete diagnostic information by checking the faulty barcode, which is understood and improved by many printers or operators. Hand-held testers can check for stains. Color When the printer considers the verification process, it considers not only black and white issues but also color issues. Bar code scanners usually work under red light, so if the background color of the bar code is red, then there is not enough contrast under red light, and the test results are not good enough. In addition, the bar code is printed on a blue background and the same contrast cannot be obtained. It is not recommended. The best method is to use a hand-held tester to test the identifiability before printing on the machine. This will give better results.