1.ink requirements
　　Ink colors should fully consider the ink color cast, Accuracy of ink bar code is also a great cast. Theoretically Just follow the color matching using barcode printing inks can meet the requirements, but due to the existence of the printing ink hue impure defects, leading to cast happen. Therefore, precise control of ink to be used should be the color, the ink density, hue saturation, high purity, preferably before the first measurement of a bar code printing ink under red light reflectance has reached the requirement. Reflective gold ink and gloss properties result in specular reflection effects, the impact of scanner reading, it can not be used for printing bar codes. In addition, the thickness of the ink and the ink concentration should also be suitable for barcode printing requirements, barcode printing is the printing field due to the optical properties can be achieved reflection of its printing inks and ink density and thickness. The printing process, the reflection density of the printing ink is increased with the increased thickness, when the thickness of the ink reaches a certain value, then the density reaches saturation. General ink saturation density requirements: black ink 1.8 to 2.0; cyan ink from 1.45 to 1.70; magenta ink from 1.25 to 1.50; yellow ink from 0.90 to 1.05; other professionals color ink is 0.8 or more. Due to differences in the printing process, the thickness of the printing ink is different, generally offset for 2 ~ 4μm; letterpress is 8μ m; flexo for 10μm; gravure to 12μm; silk screen as 30μm.
2.for the substrate requirements
　　Due to the bar code reader, the scanning light source angle of incidence is 45 °, and the angle of the reflected light is collected 15 °, when the reflection light range of 15 °, it is impossible to collect the reflected light signal, which is equivalent to a black effect. Therefore, in order to satisfy this characteristic bar code scanning, requires substrates with good light scattering properties, and not specular reflection. Therefore, the paper's white matter, opacity and gloss how, for bar code readers have a certain impact. You should also consider using good weather resistance, dimensional stability after the force, good color, small ink permeability, moderate smoothness and finish materials.
3.print quality
　　Scan the bar code symbol is read source of information, in order to ensure the correct reading, the printed bar code should be neat and clear, there should be no obvious defects of character, no blanks from dirty ink. To ensure the correct bar code reading, the maximum diameter of the defects and blemishes on the bar code should be less than or equal to 0.4 times the narrowest line width of the bar code standard. After the bar code printing and blank lines should be obvious contrast signal, which should be as large blank reflectivity, and the reflectivity of the lines should be as small as possible, PCS values (color contrast) the greater the contrast signal bar will The larger, the better performance can be read.
4.requires the printing position
　　Determine the position of the bar code symbol shall be consistent with no distortion, easy to read and the plate principle. That requirement is set on the right side of the main display packaging, or in the main display connected planar surface and the back surface of the packaging of the main display. Taking into account the characteristics of the printing process, make-up should make barcode printing direction corresponds to the direction that can only be expressed in barcode printing deformation vertical position in order not to affect the accuracy of the reading. Due to packaging, characteristic differences, barcode printing position is different. General box packaging barcode printed on the lower right side of the box; canned and bottled packaging bar codes printed on the bottom side of the label is best, but the bar code symbol surface curvature should not exceed 30 °; bar code printed on the best packaging barrel barrel the side, if the side is not printed, the barcode may be printed on the lid, but the lid must not exceed the depth of 13mm; bag-like package having a bottom and a larger bottom surface, the bar code may be printed on the bottom surface of the lower portion of the back surface or the central printed; books direction of the bar code is usually printed on the back cover of the spine or jacket bottom left corner, and the lines into parallel form. In summary, the bar code as a data input technology and automatic identification technology, widely used in the packaging of goods, it is commodity production, sales, storage and inspection, communication and information play an important role. Therefore, the correct understanding and the knowledge of the barcode and printed packaging and printing bar code is an important part.