Today, with the rapid development of the market economy, the packaging of goods is becoming more and more important. The exquisite packaging can improve the quality of the goods and the sales price has become a consensus. Therefore, the quality requirements of packaging products for various commodity manufacturers are getting higher and higher.

The large-area spot color field is a kind of contrasting and rendering method commonly used in commodity packaging design, and it is an important form that embodies the image of the product shelf. It is also the key point of the printing duplication and the quality control.

In China, offset printing is one of the main methods for paper packaging printing. The technology is mature and can reproduce very fine products. It can very well cater to the mass consumer psychology in the Chinese market, and therefore its popularity is high. Sheet-fed gravure is a printing method that has emerged in recent years. It has unique features in spot color and on-site printing, and it is very flexible to use. According to business needs, our factory purchased a sheet-fed gravure printing machine produced by Beijing Zhenhengli Printing Machinery Co., Ltd. and used it together with the original offset printing machine to achieve good results in packaging printing.

This article proposes a large area of ​​field packaging and printing. It is more appropriate to analyze which type of equipment is a sheet-fed gravure printing machine and a domestic two-color offset printing machine.

Due to the characteristics of the machine itself, the operation of the single-concave machine is very simple. The paper-feeding section and the paper-receiving section are the same as the offset printing machine. Generally, anyone who can operate the offset printing machine can operate the single-chamfer machine without special training. The main difference between sheetfed gravure printing and sheetfed offset printing is that the printing plates and inks used are different.

From the perspective of the printing plate, at first glance, it seems that the cost of gravure printing is higher, but in reality it may not be. Because the gravure printing plate is very resistant to printing force, the general platemaking factory's commitment is: At least 1 million printing times, and the packaging printing products generally larger, often also need to repeat the printing. Therefore, long-term calculations, in the printing of large-scale field packaging products, gravure and offset printing plate making costs are not very different. In addition, a good gravure printing plate rarely causes the printing quality to fluctuate due to external factors during the printing process, and the quality is very stable. Single-convex machine installation is very convenient. After the normal printing, as long as the ink viscosity is not greatly offset, the whole printing process will be very smooth, and the printing product can easily maintain the consistency of ink color.

From the perspective of the inks used, the cost of gravure inks and ordinary resin offset inks is similar, but gravure inks have characteristics such as lower viscosity and better fluidity. Due to the use of a large amount of volatile organic solvents, printing ink layers are The dry part of the gravure printing machine can be quickly dried under the irradiation of the infrared light. There is no problem of sticky printing on the printed product. After printing, the color can be printed immediately or transferred to the next process for postpress processing.

The use of offset printing technology, if the use of ordinary resin ink, the ink on the printing machine can not be completely dry, need to spray the powder in the delivery part to prevent the printing product sticky. A slight mistake in dusting control can cause the printed product to become dirty, leading to an increase in reject rate and lower production efficiency. Since the oxidative polymerization and drying of common resin type inks take a long time, the printed products cannot be processed immediately after the second printing or postpress, and it is required to stand for a period of time until it is sufficiently dried. Although the use of UV inks can eliminate various defects in the drying process of offset printing products, the printing cost will increase a lot. Even if the cost of installing UV curing devices is not considered, the cost of ink alone will be about 10 times that of ordinary offset printing inks.

Single-concave printing machine with large area on the ground, bright color, saturated hue, thick ink layer, if you use a single concave machine for water-based coating or UV coating, the color effect is better, the ink layer will be better wear resistance . The use of offset printing process in large areas, if the use of ordinary resin ink, usually printed twice to barely meet the customer's requirements, but the ink layer is thick, drying is difficult, requires a lot of dusting, to prevent the printed product sticky, Causes the surface of the ink layer to be rough and dull, and it is difficult to meet the requirements of brightness after the coating. If the post-processes are also subjected to anodized hot stamping, hot stamping will be difficult. A lot of dusting affects both the quality of the printing and the subsequent work. In addition, the use of two-color offset press printing is also prone to ink color differences, field color patterns and other issues.

Chen Henry's single-concave machine adopts an uninterrupted circulation ink supply system for ink supply. As long as the ink viscosity is controlled, the ink viscosity will not be affected by external environmental factors during the entire batch of printing. The ink was very stable before and after the entire batch of products.

However, due to the ink-ink balance problem, it is difficult for the offset printing to be consistent with the printing inks. After all, the ink level and the water level are changing all the time. Especially when printing is stopped after the stoppage, the ink color changes more, and the printing paper must be frequently added to adjust the ink color. With a gravure press, you do not need to add a release sheet. After printing, you can print immediately and you can get the same ink color as the previous print. In this way, the pass rate of printed products will be greatly improved than that of offset printing, which will reduce paper waste and naturally save printing costs.

From the perspective of the applicable paper, the single-chamfer machine has a wider adaptability, while the offset machine is less suitable for printing non-absorbent materials, such as gold and silver cardboard. Because the surface of the gold and silver cardboard is very smooth, the ordinary offset printing ink does not adhere well on its surface, and the ink layer becomes thin and the unevenness of the ink is liable to occur. The ink printed thereon is also difficult to dry; even if it is dried, the problem of ink layer falling off is difficult. avoid.

With the fierce market competition, consumers are becoming more and more critical of their products. Commodity packaging has to be developed toward high-end products in order to increase the competitiveness of their products. The use of gold and silver cardboard and glass paperboard has been continuously increasing. The offset printing process has been difficult to adapt. Printed high-grade gold and silver cardboard packaging is the most important gravure printing.

Through the above rough comparison, we can see that when printing large-area field packaging printing products, the use of a single concave machine and the use of domestic two-color offset printing press, the overall cost is similar, but in terms of printing effect and production efficiency, the use of a single concave machine than offset printing Good job.

In the following, a cigarette pack printing example is used to compare and analyze the combined process of full offset printing and gel-concave. See attached table.

Comparison of large field printing

Prints: Cigarettes made by Jiangxi Minnan Cigarette Factory with "Special Products and Cigarettes";
Model: North J2204 offset press, four-color Chen Henry, monochrome single-concave machine;
Operator configuration: domestic two-color offset press 3, sheet-fed gravure press 2;
Printing materials: 250g/m2 white cardboard;
Sheet size: 540mm × 740mm, 15 small spells;
Printing process: the combination of offset printing, offset printing and gravure printing;
Ink: standard magenta, yellow, black ink, spot color red ink, coffee spot color ink, warm yellowish ink;
Polishing: The printing product adopts partial gloss, and the polishing area is 0.294m2/sheet.

Through comparative analysis, the advantages of the gel-concave bonding process relative to the full offset printing process are summarized as follows:

1. Reduced labor intensity, combined with simple operation of a single-chamfer machine, domestic two-color offset press requires three people to operate, while a single-chamfer machine requires only two operations. According to the monthly salary of 1,500 yuan per worker, eliminating one operator will undoubtedly bring additional benefits to the company.

2. Increased production efficiency. The single-convex machine needs 15 minutes, the school needs 10 minutes, and then adjusts the viscosity of the circulating ink in 5 minutes, and it can be produced normally. It is 15% faster than the offset preparation. After the normal printing, you can print continuously at a rate of 6000 sheets per hour. The single concave machine still does not have the problem of cleaning the blanket, removing paper hair and white spots, etc. The printing time per class is 1.5 hours, and the time saved in loading the plate is 1.7 to 2 hours. Each class can increase the output of 6000×2=12000 (sheets), and one sheet is 15 small spells.

3. The waiting time for next steps is greatly shortened, new business can be developed with the increase of productivity per unit of time, equipment maintenance can be saved in time, overtime cost can be saved during peak season, product cycle can be shortened, and the competitiveness of the company in the market can be further improved. .

4. The single-convex machine does not require powder spraying, and the ink is dried by infrared rays. The required electricity cost is basically the same as the cost of the powder spraying material needed for offset printing. After water-based polishing with a single-convex machine, the smoothness and wear resistance of the surface of the print are improved.

5. Because the gravure ink layer is instantaneously dry, there is no sticky (back print) phenomenon, so the waste product is reduced.

After the "Specialty Cigarette Cigarettes" cigarette packs were switched to the single spot machine for printing spot color red and coffee spot colors, there was no sticky and dirty waste product, and the defective product rate was greatly reduced, thereby improving economic efficiency.