How to achieve perfect printing of QR code
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A good two-dimensional code design is the premise of perfect printing of two-dimensional code. In the design process, it is necessary to comprehensively consider the characteristics of the two-dimensional code and the printability.
01, size and resolution settings
The minimum area of the two-dimensional code is 19mm×19mm, and there is no shading or mottled color. It is recommended that the resolution be set to 150~300dpi. Otherwise, the size of the QR code is too small, too dense or insufficient resolution, which may lead to printing. The latter QR code cannot be scanned normally. When the two-dimensional code is a shaped two-dimensional code, the corresponding two-dimensional code size requirement refers to the true two-dimensional code size.
02, color matching
The color matching has a large influence on the maximum reflectance of the strip and the print contrast. The principle of maximizing contrast and meeting the requirements of standards are important principles to be mastered in the design and printing of QR codes. Black and white is the best choice. As long as there is enough contrast between the strip and the space, other colors can be used, but the strips cannot be yellow, orange, red, dark brown or gold. If the foreground color and foreground color of the QR code after the beautification is too close, the QR code cannot be scanned normally. In actual production, for the combination that is difficult to grasp, it is necessary to perform proofing in advance, and after the test has no problem, it can be mass-produced.
03, the generation of two-dimensional code
The information contained in the QR code is too long, which makes the generated QR code pattern too complicated and cannot be recognized. If there is more information, it is recommended to use the live code function of the forage web to generate the QR code.
04, leave the blank area size
The blank area plays the role of the two-dimensional code recognition device in preparing for scanning, and it must be ensured that the size is sufficient. In the process of scanning and reading the actual two-dimensional code, in order to avoid the interference of surrounding colors, the width of the left and right blank areas of the two-dimensional code should generally be not less than 5 mm.
Printing of QR code
Today's two-dimensional printing method mainly uses inkjet printing, which is a computer direct printing technology, in which ink is ejected through a nozzle and directly imaged on a substrate. The characteristics of inkjet printing determine that it can realize the variable data processing function that is not available in traditional printing, and can complete the printing of two-dimensional code better than the electrostatic imaging digital printing technology and the direct imaging technology of the printing machine. Printing has its unique advantages in the comprehensive manifestation of speed, cost and quality. If the QR code is not printed, there may be cases where the naked eye does not see the flaw, but it cannot be 100% recognized by the QR code reading device. Therefore, here we will mainly introduce the matters needing attention when printing two-dimensional code by inkjet printing technology.
01, adjust the paper moisture content
If the water content of the paper is not adjusted properly, it may happen that the variable two-dimensional code just printed can be recognized by the two-dimensional code reading device, but after being placed and dried, the image is deformed due to the diffusion of the ink and the shrinkage of the paper. , thereby affecting the recognition of the two-dimensional code reading device. Therefore, it is necessary to control the water content of the paper.
02, to ensure that the paper runs smoothly
The distance between the paper and the nozzle is generally about 2mm, but sometimes the tension between the paper and the nozzle is easily caused by the unstable tension of the paper feed or the flatness of the paper on the sheet feeding platform. There is a change in the printing process, which causes the QR code to be imaginary, broken or scratched. In order to avoid this, try to choose a good quality paper, flatten the paper before printing, remove the lint on the paper, reduce the roughness of the paper, and at the same time, the paper can be printed during the printing process. Perform moderate stretching to further improve the flatness of the paper. Especially when the paper passes through the nozzle, no jitter can occur and the distance from the nozzle is kept constant to ensure that the printed two-dimensional code does not float on the surface of the paper.
03, pay attention to adjusting parameters when the substrate changes
Since the two-dimensional code can be printed on a variety of substrates, when the substrate changes, it is necessary to sample and test, analyze the surface characteristics of the substrate, and adjust the technical parameters such as printing resolution and nozzle temperature to meet the production requirements.
04, to ensure overprint error
Mainly refers to the color two-dimensional code. The two-dimensional code must be neat and clear when printing. In general, we specify that the maximum value of the overprint error (the overtone of the primary color and the image) should be less than or equal to 0.4 times the nominal width of the narrowest line barcode. If the overprint is not accurate, the QR code is difficult to identify when scanning. Inaccurate QR code printing can also seriously affect production results. Some advanced equipment can fully meet the standard in this respect, and some equipment with relatively backward technology, such as overprinting is not stable, it is recommended to print the QR code in monochrome, so there is no overprint problem.
05, printing speed should not be too high
If the two-dimensional code is printed by a rotary machine equipped with a nozzle or a coding system, in order to ensure the printing accuracy of the two-dimensional code and improve the accuracy of the detection by the subsequent detection device, the printing speed of the rotary machine should be controlled to 40~ 80 m / min, otherwise it will easily lead to an increase in the scrap rate of the product. The nozzle resolution should be adjusted to 600 dpi x 300 dpi, and a disposable nozzle or a new nozzle is preferred.
06, control the amount of ink
The thickness of the ink layer is preferably <0.1 mm, otherwise the normal reading of the two-dimensional code will be affected by the strip and the space on different scanning planes. In order to ensure that the thickness of the ink layer is sufficiently thin, the ink of uniformity and diffusibility should be selected, and the matching of the ink with the substrate should be noted. In addition, since the properties such as the fluidity of the ink are closely related to the ambient temperature, the amount of ink needs to be adjusted according to the ambient temperature. It should be noted that after drying by infrared ray, the dryness of the two-dimensional code should reach 90% or more, and the two-dimensional code after drying should not have a "tail".
07, prevent content loss
Missing content during printing can cause scanning difficulties. In printing, due to paper or the like, it is easy to cause a defect in the printed pattern. For a slightly "fragmented" pattern of two-dimensional code, carefully check it during printing to avoid this.
08, other matters needing attention
When printing a two-dimensional code in batches, it is best to first scan it with a two-dimensional code reading device, and then perform mass production after testing. After the printing is completed, it should be stored as flat as possible to avoid distortion of the printed matter.