Bar codes often need to be printed on cartons and cartons. This is a printing process that must be required for the circulation of goods. Bar code, also known as line code or simply bar code, is a commonly used product packaging label, can be said to be the identity of the product. Through it can reflect a lot of information, such as the country of production of goods, manufacturers, product names, production date and other information, so that it plays an important role in the production, sales, storage and inspection of goods. Bar codes are widely used in various container packages, trademarks, and other products to become a link for communication. Therefore, it is of great significance to understand and master a number of process technologies for bar code printing and use and improve the printing quality of bar codes.
Understanding of the structure of the bar code and the principles of reading
The bar code is a graphic identifier of a set of numbers or alphabetic symbols, which is composed of bars and spaces with different widths, different reflectivity, and according to a certain coding rule (code system). That is, the bar code is a set of parallel line graphics with different thickness and arrangement according to certain rules. The common bar code is composed of black bars (abbreviated bars) and white bars (abbreviated as empty bars) with large differences in reflectivity, which are usually printed on goods. Or on the package, it can replace all kinds of text information, and can read data at any time through the photoelectric reading device. The EAN bar code system consists of barcode symbols themselves, bar code reading, interfaces, and computers to complete the input and output of commodity information. There are two kinds of barcode reading symbols, bar code symbols for the rectangular line graphics, optical scanner information readout system, mainly to read and identify these bar code symbols. The digital symbols are numbers and letters outside the line, including 0-9 digits, A-Z letters, which can be directly recognized by the naked eye, generally from 8-16 digits, and the code system has different digits. The arrangement, width, and number of lines of the bar code are stipulated by each manufacturer and determine the meaning of the code. Generally, there are marks at the two ends of the reading end-reading, and some still have numbers printed under the lines, which can be directly identified or read by an optical reader, and thus can also count, count, and manage commodities. The reading performance of the barcode system, that is to say whether the barcode system can be used normally depends on the reading ability of the system and the printing quality of the barcode. Bar code, as a kind of coded information, is a specific language that people communicate with the computer. Black and white weights and lines in the bar code symbol, thick black lines in the computer as 1, thin black lines 0, through logic conversion, can be expressed as 0-9 Arabic numerals and arrays, therefore, there must be a reading device Use it together to read. The reading system mainly includes a scanner and a decoder. The scanner is a part that directly contacts the bar code reading signal. It consists of a light emitter, a photo detector, and an optical lens. It can read the information abbreviated by the bar code at an extremely fast speed. During scanning, when the light beam emitted from the light emitter shines on the bar code, the photo detector responds according to the light intensity of the light beam reflected from the bar code when the scanning light spot sweeps onto the white paper surface or between the two black lines. In the blank space, the reflected light is strong, and the detector outputs a large current; when scanning into a black line, the reflected light is weak, the detector outputs a small current, and according to the width or width of the black line, the response is made with different lengths of time. The light and dark changes of the bar code are converted into current signals of different sizes, and after amplification, they are sent to the decoder. The decoder translates the signal into data, performs local inspection and display, and connects with the keyboard and sends it to the computer for data processing. How the bar code print quality relates to the ability to read the problem properly. Therefore, the ink is uniform, the layout is not dirty, the lines are clear without breaking, and it is the basic quality requirement for bar code printing.
Barcode printing and its problems
There are two kinds of bar code printing methods, one is the use of printing equipment for printing and graphics combined version of the layout of the layout of the batch printing. The other is controlled by a computer and prints bar code labels and bar code files in due course. The former applies to a large number of barcodes with the same specifications and the same content, and is designed and printed at the same time as the packaging graphic. The latter can be controlled by computers, real-time printing as required, with greater flexibility. Bar code printing devices include inkjet printers, thermal printers, thermal transfer printers, impact dot matrix printers, and laser printers. In order to ensure that the printed bar code meets the design specifications, the plate making process should be considered according to the printing process and the characteristics of the substrate.