How to reduce carton color difference? The master has made 6 home remedies!

[China Packaging News] The printing process is ever-changing, how can we reduce the color difference of the carton? This article summarizes the author's decades of printing production experience and mainly explains how to improve the problem of printing chromatic aberration.

1. Stable ink quality

Stable ink quality is the key factor to control color difference. Because, now many customers choose to modulate spot color ink in order to promote the uniqueness of their products and increase the anti-counterfeiting function. The matching ratio of spot color ink must be accurate, so as to ensure the stable hue of the ink, and the brightness and saturation meet the requirements.

If the quality of the ink changes, it will be " little difference, a thousand miles away . " The technical content of ink adjustment is high, and the requirements for experience are also very high. Enterprises that do not have a special ink adjuster can require ink manufacturers to send technical personnel to come to service. But in short, the quality of the ink will affect the whole body, which is related to the overall situation. It must be carefully selected and used.

In the process of using the ink, there will be problems such as increased viscosity after volatilization and changes in ink hue, etc., which should be adjusted in time according to the specific situation. In the printing operation, front-line employees, especially the captain, will find many effective local methods and small innovations in practice. All proven and effective methods must be actively summarized and promoted. For example: drip method to control ink viscosity and so on.

2. Inking performance of plates

Inking performance of plate materials, especially after long-term abrasion of plate materials. The advancement of plate technology has greatly improved the quality of printing and reduced the color difference of printed products to a certain extent, but whether it is a rubber plate, a resin plate or a flexo plate, long-term wear will greatly reduce its inking performance. Therefore, it will often cause problems such as light blotting and unsaturated ink layers. If the printing pressure is simply increased, the problem will not be solved fundamentally, and it will only cause further damage to the plate and increase the color difference of the corrugated carton, as well as the carton. The compressive strength is greatly reduced.

3. Equilibrium pressure and constant speed printing

The speed of printing and the degree of stability will bring changes in color. When the printing speed is accelerated, the lower ink amount increases rapidly, the ink layer becomes thicker, and the color becomes heavier; on the contrary, when the printing speed is reduced, the lower ink amount decreases, the ink layer becomes thinner, the imprint becomes lighter, and the ink application amount is difficult to reach saturation. Therefore, in order to maintain a stable color of printed products, it is necessary to maintain a stable printing speed. The same is true for the pressure control of printing. If the upper pressure is too large, the amount of ink drop is small, and the imprint is fragile. Printing will cause ink staining.

Fourth, control paper color, sizing degree, smoothness and other indicators

The whiteness of the paper is measured in the spectrodensitometer. The color difference between the measured and analyzed products should be subtracted from the paper, but the customer will never forgive the color difference of the printed product caused by the paper. Therefore, controlling paper chromatic aberration has also become an important task. Especially in the current carton packaging market, the use of white paper is still relatively small, and colored kraft paper and cardboard account for a large proportion. Printing on colored paper will produce a " sunglass " effect, which should be prevented in pre-press design.

The smoothness and sizing degree of the paper will also cause the color difference of the carton printing. On paper with high smoothness, the ink layer will reflect on the plane, and the color will appear bright and light; on the contrary, on rough paper, the ink layer will be diffusely reflected, and the hue will appear heavy. The size of paper sizing degree affects the adhesion of ink, and the thickness of the ink layer directly affects the size of the color difference.

5. Strict color standard management system

Generally, customers will deliver a color standard of a product. If it is a newly developed product, the customer will also confirm a color standard before mass printing. Therefore, the customer's standard is the standard, and color management must be based on the standard.

( 1 ) Respect the customer's original standard, and never change it without permission

No matter how many times the plate is changed, the technical parameters cannot be changed. Conditional items such as color density and color difference can be input into the spectrodensitometer.

( 2 ) Keep it properly to prevent loss, damage or discoloration

Improper storage of samples is very easy to cause discoloration. Once changed, it loses the meaning of the standard. If it is used to guide printing production, the consequences will be unimaginable. Therefore, a strict management system for receiving and sending must be established to provide a good environment protected from light and moisture.

6. Record Management

Records not only enable products to be traced, but process records can also make operations follow rules. According to the requirements of the ISO quality management system, there are many kinds of records, and the requirements of the documents must be compared one by one, but the items that really guide the production operations and quality control are basically fixed. After each batch of cartons is completed, the ink ratio, viscosity index, number of plates printed, machine speed, operating precautions, product inspection and measurement data, and some customer comments, etc. must be recorded in detail. All are magic weapons and wealth that are conducive to quality improvement and quality improvement.

The printing process is ever-changing, and these measures alone cannot ensure that there will be no color difference. To do a good job in color management and reduce the color difference of corrugated carton printing also requires our crew operators, inspectors, and management personnel to carefully observe and carefully adjust, diligently summarize and improve innovation. In short, color management can achieve the purpose of optimizing the printing quality of carton.