Barcode printing
Each printing method has a different bar code printing capability. The printing bar code can use a letterpress printer, a lithographic printing press, a gravure printing press and a hole printing press. Lithographic (offset, dry offset), gravure (gravure, intaglio) printing bar code identification stability, high dimensional accuracy, graphic reproduction is accurate, can be used to print the bar code with a smaller magnification factor.
Hole plate (screen) printing bar code label can also obtain high dimensional accuracy, and adaptability to the type and shape of the printed carrier, suitable for printing bar code identification with moderate amplification factor. Relief printing (relief printing, flexographic printing) is not suitable for printing barcodes with poor dimensional accuracy and reproducibility, and is generally only used for printing barcodes with larger magnification factors. Printing companies can choose and undertake barcode printing operations based on existing equipment and the above principles.
Bar code printing, the bar code printing carrier should be selected by the temperature is small, the size of the force after the stability, coloring, moderate ink diffusion, permeability, smooth material. Such as coated paper, offset paper, white paper, biaxially oriented polypropylene film, aluminum foil film, tinplate and so on. The poor degree of polyethylene film coloration, heat shrink film deformation, corrugated board infiltration enthalpies inconsistent, gold, silver cardboard metal reflective interference bar code scanning, these materials should be carefully selected, and take appropriate measures to make up for deficiencies. Printed media should use ink with good uniformity, moderate diffusion and matching with the printed carrier.
2. Quality control of barcode printing process
(1) Prepress Control
a. A prepress printing company shall, when undertaking a barcode printing business, ask the user for a certificate of the right to use the barcode, verify the authenticity and validity of the certification, and verify the consistency of the manufacturer's identification code, factory name, and original film; The uniqueness of the product item code.
Business personnel must strictly implement the “Barcode Printing Verification System†provisions and file relevant data for future reference. The storage period should not be less than two years.
b. Design three elements The color, position, and size of the bar code label are collectively referred to as the three design elements.
1 Color Design Changes in color directly affect the bar code identification bar, empty reflectivity and contrast, only to meet the GB 12904 "Product Bar Code" optical characteristics of the requirements of the bar, empty color can be read by the bar code reader.
In general, the light color has a high reflectivity and can be used as an empty color, that is, a background color such as white, yellow, or orange; a dark color has a low reflectance and can be used as a stripe color, such as black, dark blue, dark green, dark brown, etc. .
Bars, empty black and white colors with the highest print contrast, known as the safest color match. The color design should try to use the color that can be used as strips and blanks in the decoration patterns. Blindly increasing the color will increase the printing cost and limit the utilization of the equipment.
The red color can only be designed as an empty color, but it cannot be designed as a stripe color. Even if the color is brown, the red component must be limited. Otherwise, the barcode symbol will not be read. This is because barcode reading devices use red light sources.
Reflective metal luster will interfere with the normal operation of the barcode reader, so gold, silver is not used as a bar, empty color. With the emphasis on packaging and decorating, gold and silver cardboard are often used by packaging and decorating designers. In order to ensure the correct reading of barcode labels, designers should measure the reflectivity of various gold and silver cardboards to be used. Predict whether the barcode identification printed on it affects the scan of the barcode reader. For the gold and silver cardboard that cannot be printed directly on the bar code, a color (light color) should be printed on the bar-coded part before use. Coverage area should be larger than the bar code symbol, especially the left and right blank area size should not be less than 5mm.
The metal foil body color can be used as a stripe color, and the barcode reader can treat it as black due to specular reflection. Such bar code identifications as Sprite and Coca Cola cans do not affect the normal operation of the barcode reader.
For packaging materials with higher transparency, be sure to pay attention to the color of the contents. If necessary, add the bottom and avoid using the same or similar color as the strip color.
2 Location Design The principle of location design is: no deformation, easy operation and easy reading. See the national standard GB/T 14257 "Location of bar code symbols for goods".
When designing the location, we must consider whether the bar code label printing position is reasonable considering the actual situation of the packaging. Avoid designing bar code labels on the edge of the package, seams, bumps, openings, and the date of production of the cover.
3 Size Design The size design of the bar code identification is to determine its magnification factor. GB12904 “Commodity Barcode†National Standards The value of M is 0.80 to 2.00.
The printing company can determine the M value according to the user's intention, the size of the bar code mark that can be accommodated on the package, the coordination of the overall decoration, and the precision of the printing equipment.
The larger the M-value, the greater the tolerance value is, the higher the qualified rate is; the smaller the M-value is, the smaller the tolerance value is, and the lower the qualification rate is. Therefore, the printing company should avoid printing M=0.85 or less. Bar code identification.
The M value of the bar code identifier is sometimes determined on the original bar code film provided by the user. If you feel that it is inappropriate to change the M during the design, remember not to zoom in and out. Private zooming will destroy the production accuracy of the original film and cause the BWR value to change. The most secure method is to re-create the bar code film that meets the design requirements M to the encoding agency.
When printing barcode labels on heat-shrinkable film corrugated cardboard, the M value should be as large as possible.
4 Other considerations
In the bar code design, the bar height and left and right blank areas are the most easily changed.
The left and right blank areas do not have any printed symbols, but they play a crucial role in the reading of the barcode logos: It prompts the reading device to return to zero and prepares for the next scan. Therefore, the size of the left and right blank areas must not be occupied or reduced when designing. The color of the left and right blank areas must match the color of the hollow bar code.
The truncation of the high-size bar will affect the first-read rate of the bar code label. Therefore, in general, do not change the bar size at will.
In addition to the need for designers to comply with the "Barcode Design Review System," they must also keep track of national laws and regulations, national standards, and international standards, and other relevant documents to understand the technical requirements of national laws, regulations and standards, to ensure that the user's product packaging is not available in the market. problem. For example, food packaging should meet the requirements of the "Food Hygiene Law" and "General Standard for Food Labeling"; packaging of export products should also pay attention to the requirements of the importing country's technical regulations for packaging, printed materials, and recycling, recycling, and prevention of environmental pollution; “Product identification standard regulations†shall have warning signs or Chinese warning instructions for products that are likely to cause product damage or may endanger human health and personal and property safety.
In order to ensure the quality of barcode printing, printing companies should select staff with strong work ethic, meticulous style of work, rich design experience and aesthetic sense, strong sense of creativity, familiar with barcode basic theoretical knowledge and related national standards, technical regulations, etc. to take charge of barcode design review work. .
c. Printing suitability test In order to ensure the quality of barcode printing, printing companies should do bar code printing suitability tests for different equipment, printing media, and printing carriers. Through the test to understand and master the adaptability between the above printing conditions, determine the design parameters of the original bar code film.
Printability tests should be performed whenever there is a change in one of the printing conditions.
The bar code printing suitability test can determine the minimum magnification factor Mmin and the bar width adjustment amount BWC under the printing conditions. When the BWC is positive, it is the BWI, while when the BWC is negative, it is the BWR.
The bar code printing suitability test standard rule is provided by a coding organization, and the bar code printability test method is described in the “Product Bar Code Printing Suitability Test Methodâ€.
In principle, users of bar code identification should order the original bar code of the bar code according to the parameters of the bar code printing suitability test conclusion provided by the printing company, but in actual work, the bar code film has been prepared by the user before the printing company is determined. The various parameters marked on the film are data given by the coding agency based on experience. Therefore, when receiving the original bar code provided by the user, the printing company should carefully verify the data on the film and make appropriate adjustments according to its own printing conditions.