As the product packaging cartons, colorful, ink evenly, hue accurate print quality control is a basic requirement. Circumstances indicate that the printing process, carton printing color management and control, always run through the whole process of production, that is, only from the printing layout to prepress production process technical checks; technical control from the printing operation to India after the decoration process; from the use of printing inks to the printing equipment maintenance and other sectors, must conduct a comprehensive check and control, in order to print beautiful color carton products. Therefore, good management and control of color cartons, printing quality from the source to the whole process of printing need to be careful technical checks, in order to better improve the quality of color printing.

Impact on the role of printing color factor analysis

Throughout the printing process, color printing carton impact on the role of many factors, but to make carton printing color management and control, we must first correct understanding of the impact of the printing color effect on several factors, it is very important.

Production practice situation indicates that the production of technical prepress grasp the extent of the computer, copy the gatekeeper of technology is appropriate, as well as the adjustment of printing pressure, gaskets feature, the machine precision, performance, including Ink device structure is reasonable, but also affect the printing the color of the main factors.

Substrate surface gloss, ink absorption, ink density, gloss also affect color printing; also finishing process characteristics, factors that will affect the accuracy of color reduction, therefore, usually to good at summing up experience in production, careful consideration of various factors, scientific and reasonable for color management and control, in order to improve the color quality of the printed cartons.

By design the control plate printing color

We know that the printing process is actually the process of copying the original, while prepress computer-printed color effect is an important part of the decision. Outlets fineness of color prints, tone reproduction whether to pursue an appropriate degree of color correctly restored with crucial influence.

Only the correct setting forum highlights, shadows, midtones can accurately reflect the level of the original contrast and accurate setting outlets should fully take into account the characteristics of substrates and inks, but also according to the printing process and machine performance to offset printing process, for example, fine print bright tone reproduction standard of 2% -4% dot area; generally brighter tone reproduction prints of 3% -5% dot area; ordinary bright tone reproduction prints of 4% -6% dot area.

When the substrates, good gloss, press performance and good conditions, with high-grade printing ink can be made brighter tone outlets within the range of 2-4%, making layout light, medium and dark tone distinct, clear hierarchy, it is more natural color reproduction. However, if the substrate is not good surface gloss, and the ink absorbing case of strong, bright tone dot to be considered a minimum set at 4-6%, or set at about 8%, or, may be small dot India does not arise out of the situation, the layout level transition becomes insufficient coordination and affect the natural color performance.

As we saw in the first printing pre-printed paper cartons when adjusting the amount of ink has been very saturated, but the layout color or light-colored shading pattern did not show it, and digital color proofs shading pattern is relatively clear, so that the actual printing effects can not be accepted by customers. The inspection film has very shallow reticulate pattern, however, copy after some lost. Then open the computer files, can clearly see the screen shown outlets gradient shading pattern, after inspection colored outlets were set at 1-4% per annum, that is, part of the largest layouts bright tone outlets only 4%. Originally, when the customer is making the colors displayed on the monitor to achieve their visual requirements for the degree, determine the layout bright tone shading network settings.

In addition, the direct printing digital proofing, material much better than cardboard, digital printing process less hierarchy does not exist to film, proofing process tiny dot loss occurs ills, these conditions do not craft experience for customers and production staff, and the lessons is profound. Later we will file appropriate textured increase overall layout adjustments to the smallest parts of bright tone outlets up to 5%, so that the re-plate making and printing, textured layout reached levels close to the originals, in line with the customer the color of the layout requirements.

Through the rational design of printing color screen angle control

Dot color layout, only colored version of the angular difference between the design of suitable network cable after printing to render a layered pleasing, comfortable color effects. If, two or more different angles with overlay networks, the networks are not allowed angle difference, will produce Moire phenomenon, affecting the normal reproduction of the color printed image.

So, with the lithographic process printing carton paper, according to the size of the ink light reflection coefficient consider the design of screen angles. Because the reflectance of the light yellow ink, followed by the magenta ink and a cyan ink, and the dark black ink color, the minimum reflectance to light.

Reflectivity greater the closer the color white, the color compared with similar paper, because weak color dot pattern consisting of eye-catching enough, so often the printing process, the habit will yellow version arranged at 0 degrees or (90 degrees), The blue, black and magenta version is designed to be 15 degrees, 45 degrees and 75 degrees for printing. Because screen angle of 45 degrees with the visual effects and feel the most comfortable, so the original color of the main color screen cable should be printed using 45 degrees, and 15 degrees and 75 degrees is scheduled to give the other two strong colors.

Screen angle in addition to taking into account the nature of the ink, but also take into account the various factors into account, Flexible printing color sequence, you can not use rote practice. With warm colors such as yellow and magenta portraits play a leading role in the layout should primarily highlight the face and skin color, screen angle can be arranged for the yellow version 0 degrees, 15 degrees blue version, magenta version of 45 degrees, the black version 75 degrees, magenta and yellow version of this difference of 45 degrees, not easy to produce significant moire phenomenon.

The main screen in cool tones, such as fruit green layout based cartons, because the screen is the dominant color is green, so it can be yellow version of the screen angle is 0 degrees arrangements, magenta edition of 15 degrees, green edition of 45 degrees, 75 degrees for the black version for printing. Press the yellow version also can be 0 degrees, 15 degrees black version, blue version of 45 degrees, 75 degrees magenta version of the design screen angle. If the original color screen in both the figures, there are green, you can use the yellow version of the dot area appropriate to increase, while the cyan, magenta and black three color version remains unchanged.

Flexographic and lithographic printing process technology in different forms, flexo ink transfer process is the use of roller, roller textured If 45 °, then screen angle should try to do a 45 ° angle, so as to better avoid printing Moire phenomenon occurs. General flexo colored lines at an angle of: Y90 °, M15 °, K30 °, C60 °. Overlapping color screen angle pattern design and layout should be the main point of difference of 30 ° hue is appropriate, such as fruit and vegetable cartons screen layout is based on a multi-tone green, then blue and yellow angular difference is necessary to master at 30 °, in order to better prevent moire phenomenon appears when printing, the printed colors are more comfortable visual effect.

Gatekeeper control via copy color printing technology

Shaizhi reticulate structure layout, the right technology to master is to ensure accurate reproduction of network layout is one of the important aspects. If excessive exposure proofing, proofing and easy to make out some small bright tone dot layout too much is lost, the phenomenon of large outlets appear narrow, so the pattern printed color becomes lighter situation occurs, do not meet quality color printing requirements. Conversely, if the exposure time is short copy, copy layout after relatively large outlets, pattern color will appear darker situations.

General density of the network, the exposure time is relatively higher than the normal exposure time should be increased by about 50S so, to make the light through a portion of high dot density, in order to facilitate the decomposition of the photosensitive layer, to improve the quality of the copy. Conversely, if the layout dot density is low, the exposure time than the normal copy exposure time should be reduced by approximately 25S so, otherwise dot layout into several smaller parts, at the same time under the irradiation of ultraviolet rays easily transmitted through the photosensitive layer of varying degrees photochemical changes, copy the network quality is comparatively more stable.

In order to be able to faithfully reproduce the layout textured original settings textured layers, preferably each batch (kind of) PS version before use, should do first exposure test, through the test strip detection, to master the PS version of the best exposure time, which is controlled by a suitable amount of exposure of the important technical measures.

In addition to the exposure impact dot reproduction, the development is appropriate also have a greater impact. Thus, the concentration of the developer according to the PS plate to determine the alkali resistance of the preparation methods, such as 95% of the hollow after developing outlets clear, 5% of the black dot is not lost, indicating that the developing concentration is modest.

In addition, if the developing temperature is too high, easy layout smaller outlets, generally developing temperature should be controlled at about 20 ℃, the developing time control in 60S is appropriate, can better ensure the quality of textured version of the copy, which is the realization printing color correctly restore the basic link.

By printing technology gatekeeper control printing color

Process practice situation indicates that the printing pressure is appropriate for printing the correct color reproduction have some influence, especially offset and flexo process, when the printing pressure is too large, the layout dot gain increases prone situation, printing color on will be significantly darker. On the contrary, the printing pressure is not enough, the printing layout of the network becomes less real, the color will be significantly lighter case.

Visible pressure directly affects the degree of difficulty printing color, then the printing pressure pad as a medium pad hardness characteristics will also affect the printing color reproduction, when the texture is too soft pad printing layout of the network in the transfer process , the emergence of deformation coefficient is comparatively large, color printing becomes heavier. Therefore, the print outlets layout of products, should adopt a neutral non-deformable rigid liner, such as insulating paper, cardboard, kraft paper, film base and other hard materials, it is more appropriate.

In addition to printing pressure, cushion characteristics of color printing, the printing speed will also affect the color printing, such as printing excessive speed, the machine inking system temperature will rise, because the reasons for leaving thixotropic ink ink thinning, printing color will appear subdued situation, therefore, to ensure the stability of color printing, should remain moderate constant speed for printing.

By using ink color printing technology gatekeeper control

Printing color ink is the basic material, but also affect the color reproduction of the important aspects of the use of a low-ink printing fineness textured layout product, then, since the ink pigment particles thick, easy to make network printing layout scared while prone paste version ills, printing color becomes heavier. Fineness not good, but also make printing plates resistant rate of decline appears Variation dot area, resulting in inconsistent shades before and after printing. Therefore, color printing carton textured layout products should be used fineness of ink for printing.

Fineness of the ink, the concentration of large, strong coloring, can printing outlets clear, full, colorful, and stability. Therefore, the high-end color box, box products, the best high light, durable ink, which can better improve the quality of printing ink color.

After choosing the right printing ink, but also pay attention according to the printing machine, ink substrate characteristics and performance, adjust the ink viscosity and fluidity. Especially when the machine inking system accuracy and strength of the substrate surface is not a good objective circumstances, if the ink viscosity is too large, easily lead to uneven ink transfer, brushed, flower paste version version and other adverse conditions. Conversely, if the ink viscosity, the ink is easily emulsified, and to layout in loose dirt and other adverse conditions, will also affect the correct printing color reproduction.

Taking into account the viscosity of the ink, its mobility is relatively smaller; viscosity of the ink, mobility is large, will cause the printing dot reproducibility is poor. The ink flow is too large, easy to make printing outlets owe full, clarity is poor. Therefore, the ink viscosity and fluidity is insufficient to maintain the stability of the quality color printing, can be used to adjust the ink suitable additives printability.

The varnish used is 6 # 0 and #, 6 # varnish used to increase the fluidity of the ink, the ink transfer to improve performance and reduce the ink density, viscosity and drying speed. The 0 # Varnish is a high viscosity, when the ink viscosity is too low, uneven inking, ink blur, we can use the right amount of 0 # varnish Stir in the ink can be achieved by increasing the ink viscosity and The role of adhesion, to improve the quality of color printing technology results.