Color management in the printing process occupies an important position in the entire color management system, because the quality of work at this stage is directly related to the quality of batch products, especially in the field of cigarette label printing with stability as the first requirement. Poor control, ranging from batch scrapping to customer complaints and returns, and the direct impact on their reputation.
1. The importance of data standards
The so-called standardization is the maximum degree of standardization. The same process conditions, different locations, different times, and different operating staff to print, the effect should be completely consistent. This requires the measurement and control of process parameters to stabilize the process conditions. This requires us to determine the key processes in the printing process according to the characteristics of our company. All the processes in the printing process must be well controlled to achieve the purpose of professional production.
In traditional printing production, employees' thinking is perceptual, empirical, and disorderly, often adopting the method of masters and apprentices to impart skills. In the thinking habits of some teachers, it is always believed that printing production relies on the experience passed on from generation to generation. It is unclear and unclear. If you have more experience, you will know it naturally. In fact, this is an unscientific and rigorous approach. Modern printing requires many steps to complete together, to maximize cost savings, improve production efficiency and ensure stable printing quality, it requires a scientific and strict system and process.
The standardization and standardization of enterprises can form strong productivity. A research institute in London, UK has done a lot of long-term data statistics, and concluded that 13 of the economic growth in Europe is due to standardization, which is much higher than the economic drive of patented technology. We must be keenly aware that the rational age of the printing industry has arrived. In recent years, the business strategy alliance formed by a number of printing industry suppliers and academic groups has promoted a unified "job identification format", both by establishing standard "output" and "input" information formats, thereby controlling The effective operation of the production process has become the consensus of "standardization, digitization and standardization" in the industry, and is known as a milestone in the standardization of the printing industry.
Standardization is indeed conducive to printing quality control, effectively reducing costs and improving service levels. The printing production process is long and complicated. The control of printing quality lies in the whole process. Any process link is not handled properly, the skill level of the operators in each link is uneven, and the operation is not standardized. It is impossible to produce high-quality printing products. For each production process, set up control points and control elements to control whether the process meets the standard requirements as the basis for the next process.
Second, the color data of cigarette pack products
For printing companies, while formulating the color quality standards for printed products, the quality standards of the printing materials (ink and paper) must be formulated and effectively controlled to achieve the required print quality. The tolerance range of the color of the printed matter and the paper can adopt the same control standards as the users of the printed matter (cigarette enterprises); or, according to the production conditions of the printing enterprise, relatively strict control standards
The standard chromaticity coordinate value of the ink can be the same as the specified target color of the printed product; or, the data obtained by measuring the color sample of the ink obtained after the specified ink is scraped using an automatic ink scraping sample machine, as the The standard color coordinate value of the ink. In this way, the incoming ink does not need to be printed on the machine, and it can be easily detected and controlled. The color difference of the printed product is a comprehensive performance of all influencing factors. Therefore, for the quality control of the incoming ink, a relatively strict qualification tolerance must be formulated Range, so that the printed product obtained after the color difference changes caused by other influencing factors after printing can meet the final quality requirements.
1. Formulation of target color standard chromaticity value
Cigarette trademark color quality management can use spectrophotometer and color data processing system. The minimum measurement caliber is 3mm; therefore, the actual measured area of ​​the color measured on the cigarette trademark must be greater than 3mm to make sense; it must be greater than 5mm to facilitate the staff to detect and obtain good repeat accuracy.
After the cigarette trademark is wrapped, it will be covered, and will not affect the sizing area, and print 5-8mm diameter detection color blocks for all colors that need to be controlled.
Sampling 20 to 100 or more proofing trademarks, after visual observation by the standard-setting department with human eyes, meets the design color requirements and the difference between the proofs within the width of the human eye proofing trademark as a standard color sample.
Carry out chromaticity measurement and statistical calculation for each color of the above standard color samples, and calculate the average value of L, a, and b as the standard chromaticity value of the color in the trademark; or use the target color in the color quality control software In the setting function, the average value measurement sets the standard chromaticity value.
Repeat the above operations to formulate the target color tolerance range of L, a and b standard chromaticity values ​​for different trademarks and different colors.
2. Use the ΔECMC eligibility determination method to formulate the tolerance range
According to the product quality requirements, a reasonable commercial index difference value (different colors with consistent color quality requirements only need to set the same value) as the final color quality qualification judgment tolerance range.
3. Means of production process control
Generally, process technicians always want to maintain constant process parameters and technical methods for production. But in the actual production process, due to one or another factor change, it is often difficult to achieve this ideal production conditions. Especially for inks, due to the constraints of the chemical and pigment industries, it is impossible for inks produced in different batches to maintain the same quality level, especially the quality fluctuations between batches with long production dates. Therefore, before printing, it is necessary to adjust the specific process parameters on the basis of the original process standards for the actual production conditions such as material changes, so as to ensure that different batches of printed products obtain satisfactory and stable color quality.
Example 1: When the color saturation of the ink is slightly higher than the standard, and a new printing plate with relatively deep scores is used, the viscosity of the ink should be reduced or the printing speed should be increased to adjust the thickness of the ink layer of the printed product to reduce the printed product accordingly. Color saturation.
Example 2: When the ink color is consistent with the standard, and the paper is slightly yellowish. Then, the ink color of the printed product printed on a large area must be slightly yellowish. Therefore, the paper with relatively high whiteness must be replaced, or the yellow component of the ink color should be adjusted appropriately. In this way, the final quality requirements of the color of the printed matter can be achieved.
4. Quality control
During the printing process, due to the random errors of the printing equipment, the technical capabilities of the operator, the volatilization of the ink composition and the change in viscosity, the blockage of the printing plate, the fluctuation of the printing speed, the change in the drying temperature, and the change in the environmental temperature and humidity All will cause the color quality fluctuation of the same batch of printed products. Therefore, it is necessary to use a color difference meter to conduct timely sampling and testing of semi-finished products during the printing process, understand the color difference of the printed product and adjust the process parameters in time, and control the color quality of the printed product to fluctuate within the smallest change range. Thereby reducing the scrap rate of printed products and improving economic efficiency. According to whether the printing equipment is equipped with a slitting mechanism, a corresponding random sampling time shall be formulated to timely sample semi-finished products for printing.
5. Use color difference measurement to detect randomly sampled products for color difference analysis
Note: The color difference analysis in the quality control process is not a judgment of the conformity of printed products. If the sampling test results exceed the tolerance range of the qualification, the process parameters are adjusted to control, which will cause many unnecessary waste products. Therefore, it is necessary to adjust the process parameters in time according to the actual color deviation. Combined with the relevant content of the CIELAB system in the basic theory of color, the color difference bias analysis was performed on the above sampling test data.
Kitchen Utensil,Chef Knife,Steak Knives,Potato Peeler
Liveon Industrial Co.,Ltd. , https://www.liveonkitchen.com