In cartons, cartons products often need to
print bar codes, which is a necessary printing process for commodity
circulation. Bar code, also known as line bar code or bar code for short, is a
common commodity packaging label, which can be said to be the ID card of
commodities.
There are two
ways to print bar code: one is to use printing equipment to batch print the pages
which are combined with printed pictures and texts. The other is controlled by
computer to print barcode label and barcode file in time. The former is
suitable for bar codes with large quantity, fixed specifications and the same
content, which are designed and printed at the same time with the outer
packaging graphics and text. The latter can be controlled by computer to
achieve real-time printing according to requirements, with strong flexibility.
Barcode printing equipment includes ink-jet printer, thermal printer, thermal
transfer printer, impact dot matrix printer and laser printer of China printing.
In order to ensure that the printed bar
code meets the requirements of design specifications, the plate making process
shall be considered according to the printing process and substrate
characteristics.
For example, in flexographic printing
process, the appropriate reduction of line width can be considered in plate
making to make up for the expansion deviation caused by the deformation in
printing. For printing heat shrinkable packaging materials, the position of the
barcode after the film shrinkable should be considered, and the longitudinal
and transverse shrinkage coefficients should be calculated in advance, so that
the layout can be adjusted according to the shrinkage coefficient during plate
making.
In order to facilitate the normal reading
in use, we should pay attention to the selection of the printing ink color of
the barcode. For the barcode reading system, the scanner light source is
generally a red light source with a wavelength of 630 ~ 700nm, so the red light
effect of ink color should be considered in China Printing.
When the incident light of the scanner
irradiates the barcode surface of different materials and colors, the
reflection effect is also different.
Black ink can completely absorb red light,
and the reflectivity of printed matter to incident light is generally less than
3%. Therefore, most barcodes are designed to print in black ink color. The
white ink is completely reflected to the red light, and the reflection of the
printed product to the incident light is close to 100%, so it is the most ideal
blank color.
For the above reasons, most of the bar
codes on the printed matter are directly printed on white paper. However, some
packaging products, from the design and process effect, also have the choice to
use other colors for printing, so we should pay attention to match according to
the nature of color. Generally, the colors with high reflectance to red light
include yellow, orange, red, light brown, etc., while green, black, purple,
cyan, etc., with low reflectance to red light in China Printing.
In order to design the printing color of
bar code reasonably, the reflection of color to red light and other factors
should be fully considered. Transparent film packages are not suitable for
direct printing of bar codes. White ink or yellow or orange red shall be
printed as the substrate first, and then dark bar codes, such as black, dark
green and dark blue, shall be printed, so as to be easy to read and use.
