02, to ensure that the paper runs smoothly
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The distance between the paper and the nozzle is generally about 2mm, but the tension between the paper and the nozzle can easily be caused by the unstable tension of the paper feeding on the web or the fact that the flatness of the paper cannot be controlled within a suitable range on the single sheet feeding platform. Changes occur during the printing process, resulting in the emergence of two-dimensional code virtual, broken or scratched dirty phenomenon. In order to avoid this happening, we should try to choose good quality paper, flatten the paper before printing, remove the powder off the paper surface, reduce the roughness of the paper surface, at the same time in the printing process on the paper Extensive stretching is performed to further increase the flatness of the paper. In particular, when the paper passes through the nozzle, no shaking 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, adjust the parameters when the substrate changes
Because 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 substrate surface characteristics, and adjust the print resolution, nozzle temperature and other technical parameters to meet the production requirements.
04, guarantee overprint error
Mainly refers to the color two-dimensional code. When printing, you must ensure that the QR code is neat and clear. In general, we stipulate that the maximum value of the overprint error (overprint error of the main hue and the picture) should be less than or equal to 0.4 times the nominal width of the narrowest line bar code. If overprinting is inaccurate, the QR code will be difficult to identify when scanning. Inaccurate two-dimensional code printing can also seriously affect the production results. Some of the more advanced equipment can fully meet the standards in this regard. For some equipment with relatively backward technology, such as overprinting, it is recommended that the two-dimensional code be printed in monochrome, so that there is no overprint problem.
05, printing speed should not be too high
If two-dimensional codes are printed using a web printer equipped with a nozzle or a coding system, in order to ensure the accuracy of the two-dimensional codes and improve the accuracy of the detection of the two-dimensional codes, the printing speed of the web printer should be controlled to 40 to 80m/min, otherwise it is easy to increase the rejection rate of the product. The printhead resolution should be adjusted to 600 dpi x 300 dpi, and disposable nozzles or new nozzles are preferred.
06, control the size of the ink
The thickness of the ink layer is preferably < 0.1 mm, otherwise the normal reading of the two-dimensional code will be affected because the bar and the space are on different scanning planes. In order to ensure that the thickness of the ink layer is sufficiently thin, ink with good uniformity and diffusibility should be selected, and the matching of the ink and the substrate should be noted. In addition, since the performance of the ink such as fluidity is 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 infrared drying, the dryness of the two-dimensional code should reach more than 90%, and the two-dimensional code after drying should be guaranteed to have no "tail".
07, prevent content loss
Missing content during printing can cause scanning difficulties. During printing, the print pattern may be easily damaged due to paper or the like. For a slightly “fragmented” pattern such as a two-dimensional code, be careful when printing to avoid this situation.
08, other matters needing attention
When printing two-dimensional codes in batches, it is best to use a two-dimensional code reading device to scan the device first, and then conduct mass production after testing. After the printing is completed, it should be stored as flatly as possible to avoid distortion of printed materials.