In recent years, as competition in the label printing industry continues to intensify and customers’ requirements for products have increased year by year, label printing companies have paid a lot more attention to quality inspection than before. At the same time, the quality inspection system has been developed in China’s label printing industry for more than ten years, and the functions and performance of the equipment have also undergone great changes. In this paper, the author analyzes the current application status of quality inspection control in the label printing industry from the perspectives of the causes of problems that are prone to occur in the quality inspection process, the quality inspection technology, and its characteristics that the label industry pays attention to, and the future development trend of quality inspection technology.
Reasons for problems in quality inspection
In recent years, although label printing companies pay more attention to quality inspection than before, there are still many problems in the actual production process, as follows:
(1) Wrong thinking concept. Some label printing companies believe that the purchase of a rewinding quality inspection machine can guarantee the printing quality of the product, that is, the quality inspection machine picks out the waste at the last pass, so as to provide customers with qualified products. However, everyone knows that the quality of any label product is printed, not detected. If the printing quality of label printing companies cannot be improved, how can they provide customers with stable label products and it will be difficult to use them well? Quality inspection machine.
(2) Wrong understanding. At present, some label printing companies buy quality inspection machines just to show their customers. Some companies cannot participate without the quality inspection machine when bidding or making certain labels, but they do not use the quality inspection machine.
(3) Insufficient understanding of quality inspection machines. Some printing business owners think that everything will be fine if they buy a quality inspection machine. In fact, it is not the case. The use process of the quality inspection machine is gradual and requires constant running-in. During the use process, the production management personnel need to summarize the root causes of the problems based on the defects detected, and then analyze the defects in the printing process. It is produced in the subsequent die-cutting, bronzing and other processes, and then based on the analysis results to formulate improvement plans to try to avoid or reduce the frequency of such problems. According to this cycle, label printing companies will greatly improve the quality of label products.
(4) Insufficient attention is paid to pre-press and India-China. At present, most label printing companies still believe that offline quality inspection machines can control the final quality of the factory. In fact, if the company does not pay enough attention to pre-press, it may cause problems with the entire batch of products, resulting in complaints or even loss of customers. Such examples are not uncommon, especially now that a large number of rotary presses and flexographic machines are put into production, and the production speed is extremely fast. During the production process, it is difficult for operators to detect printing defects in real-time with the naked eye, which may cause large-scale continuity defects.
Quality inspection technology and its characteristics concerned by the label industry
Based on this, as an important part of quality control, quality inspection technology can be divided into pre-press inspection, in-press inspection, and post-press inspection according to the production process. For these testing links, a variety of testing equipment is included, as follows:
(1) Pre-press inspection
With the intensification of market competition, label printing companies pay more and more attention to the pre-press link and pay more attention to plate making and first proofreading to prevent batch defective products.
(2) In-print inspection
According to different production equipment, the online inspection can be divided into rotary machine online inspection system, flexo online inspection system, and inkjet online inspection system. Among them, the rotary machine online detection system and the flexo online detection system are mainly used to control the quality of printing quality, and the inkjet online detection system is mainly used to control the quality of variable data information in the inkjet process.
(3) Post-press inspection
According to the number of cameras, installation methods, and platform functions, a post-press inspection can be divided into single-station quality inspection machine, double-station quality inspection machine, front and back quality inspection machine, roll-cut single-sheet quality inspection machine. among them:
Single-station quality inspection machine is currently the most widely used testing equipment on the market, with a share of more than 95%. It has the advantages of relatively simple use, overall stability, easy to learn and use, and low price, but it is difficult to apply to certain special process detection.
The double-station quality inspection machine has gradually been accepted by some high-precision customers. One camera detects the printing quality and variable data, and the other station detects the needs of UV ink, small film folds, infrared ink, ultraviolet ink, etc. Can meet the diverse needs of customers.
The front and back quality inspection machines are currently mainly used in some ticket inspection and transparent rubber printing inspection products. It can inspect two sides at a time, which greatly improves production efficiency, reduces process flow, and helps companies improve market competitiveness.
Reel-cut single-sheet quality inspection machine is mainly used for reel printing and single-sheet products. In the past, this label product was mainly inspected manually, which had the disadvantages of high cost and unstable detection effect. The equipment used the characteristics of roll inspection, and the tail was added to cut single sheets, bad products were discarded, and good products were collected according to a fixed number. For stacking, it has the advantages of one machine with multiple functions, reducing labor costs, and stable testing products.
The future development trend of quality inspection technology in the label industry
According to the solutions that adapt to the different scales of the large, medium, and small enterprises, the common quality inspection machine solutions are mainly divided into two types, as follows:
(1) Integrated product inspection solution for pre-press + print-in + post-press. The solution is mainly aimed at large and medium-sized label printing companies. On the one hand, this type of label printing company must establish the company’s brand image, on the other hand, it must improve the company’s automation level, reduce the influence of human factors, and eliminate batch waste. The emergence, enhance the company’s overall competitiveness. The solution has many advantages, but the disadvantage is that the investment cost is high.
(2) Solutions for post-press quality inspection. This solution is mainly aimed at small and medium-sized label printing companies. On the one hand, this type of label printing company must ensure the printing quality of the products out of the factory and prevent waste products from flowing into the client, and on the other hand, cooperate with the final customer to audit the factory for follow-up Development provides a good foundation. The disadvantage of this solution is that the online printing quality cannot be controlled in real-time before printing. If a large number of printing defects occur during the production process, even if these printing defects are detected in subsequent inspections, a large amount of production waste will be caused.
In order to meet the diversified needs of customers, suppliers in the quality inspection industry have also demonstrated their abilities, and each exerted their own technical advantages to produce a series of quality inspection equipment with competitive advantages in the market. For example, the author’s Zhongheng Yongchuang (Beijing) Technology Co., Ltd. can provide a full set of inspection solutions, including the first pre-press comparison software, the in-print flexo online inspection system and the inkjet online inspection system, and the post-press single station inspection, Double-station inspection, front and back inspection, roll-to-cut single sheet inspection, etc., can fully meet the needs of customers at different levels.
It is worth mentioning that this inspection system software is independently developed by the company and has independent intellectual property rights. The company’s quality inspection system has simple modeling operations, intelligent learning algorithms, modular algorithm libraries, multi-CPU programming, and GPU The characteristics of the combination of technology, and the matching detection of digital printing machines can be installed digital online detection, especially the variable information detection technology is a highlight of the company, the image processing, and machine vision technology are well applied to the label industry. Affected by the epidemic this year, the company pays more attention to the research and development of new products, digs deep inside, cultivates internal skills, and introduces deep learning technology, automatic positioning, and intelligent rapid modeling technology into the label quality inspection, and contributes to the development of the label industry. A meager force.
At present, short individualization or long order relative immobilization has become a mainstream development direction of today’s label printing industry. This requires quality inspection and testing to develop in these two extreme directions, and the requirements for quality inspection and testing are becoming more and more stringent. It is necessary to meet the needs of personalized and rapid modeling and testing and to ensure long-term stability testing needs. In accordance with the requirements of the national deployment of industry 2025, the label quality inspection machine should realize a fully automated substitute standard method, and be combined with the die-cutting machine as a multi-function machine equipment, reducing manual participation and reducing labor costs; the first before printing is compared to eliminate batches The production of waste products; the in-print inspection method reduces the production of batch waste products; the automatic quality inspection mode after printing ensures that each label is a perfect product.