The development of printing technology in half a century 1.6

Ups and Downs of Printing > Ups and Downs of Gravure Printing in Section VI

According to different gravure printing process, gravure printing is divided into gravure printing and gravure printing (ie, shadow printing). The former is mostly used for security printing such as securities and licenses, while the latter is good at color image printing. According to the gravure type and model, gravure printing is divided into platform gravure printing and rotogravure printing.

For half a century, China's gravure printing has gone from being small to big, and then it has been replaced by plain printing instead of declining. After the 1980s, it was rejuvenated. There are of course the intrinsic reasons behind the intaglio's own plate making, printing process and technology, as well as external influences.

Printing> First, engraving gravure printing

Engraving and gravure printing has historically been used primarily for securities, and is rarely known in general printing plants.

1. Platform gravure printing

Platform gravure printing is an older gravure printing method using a platform gravure printing machine (commonly known as a large motor). The gravure plate is flat and placed on the platen of the machine. The platen rotates along the quadrilateral route under the drag of the motor. In the course of operation, the platen stage completes several processes of inking, erasing, printing, embossing, and uncovering paper. In addition to the layout table running by the motor drag, other operations are completed manually, labor intensity, low production efficiency, printing 500 or so per hour.

In flat, convex and concave printing, the printing pressure of plain printing is the lightest, followed by embossing, and the printing pressure of gravure printing is the heaviest. The gravure image area is lower than the gravure plane. When printing, it needs to put a lot of pressure on the paper to press the paper into the depression of the image, so that the ink in the net pit is transferred from the printing plate to the paper. In the early gravure printing process, in order to make the ink on the printing plate easier to transfer to the printing paper, the paper must be moistened before printing to make it soft, and the printing sheet is dried after printing. Because the ink layer of the gravure is thick, in order to prevent the printed surface from getting dirty after the ink is printed, the printed sheets must be separated one by one after printing. The printing speed of the platform gravure printer itself is very low, and the auxiliary processes such as the wet paper before printing and the drying after printing are manual operations, so the labor intensity of gravure printing on the platform is very high, and the production efficiency is very high. low.

2. Gravure gravure gradually replaces platform gravure

In the late 1950s, the old-fashioned platform gravure press was gradually replaced by advanced rotary gravure presses. The thickness of the rotogravure printing plate became thinner, and the arc was mounted on the printing plate cylinder. Not only did the printing speed increase, but also automatic feeding, automatic delivery, and automatic wipe printing were used. In particular, the printing pressure was increased, and the dry paper printing process was adopted, which eliminated the prepress wet paper and the postpress drying treatment, which improved the production efficiency.

Engraving gravure printing wipes is always a problem. In the platform machine is an artificial wipe version, in the rotary machine you must use automatic wipe version, wash the ink device. The organic solvents used for washing ink are prone to volatilization and hinder personal health. For the sake of the environmental sanitation of the workshop, the rubbing device of the printing machine is generally made into a closed system so that the organic solvent can be recycled after being recycled.

The rise and fall of printing> Second, the rise and fall of photogravure printing

Although the engraving gravure has a strong anti-counterfeiting ability, it cannot be used to copy a color continuous tone original. Like the albums, pictorials, stamps, etc., if the manuscripts with strong artistic color are printed in gravure, they must be printed in gravure.

Photogravure printing, also known as shadow printing, has been described in the third quarter of this chapter. This section mainly discusses the printing technology of gravure printing.

As early as the 1920s, Shanghai Commercial Printing Factory introduced photogravure printing technology. In the early 1950s, in order to improve the printing quality of "People's Pictorial," the General Administration of the Press decided to transfer some gravure plate making, printing equipment and technical personnel of the Shanghai Commercial Printing Factory to the Beijing Fine Arts Printing Factory (later merged into the Beijing Xinhua Printing Factory). . In the 1950s, Beijing Xinhua Printing Factory, 1202 Factory, and Beijing Stamp Factory had successively established photogravure plate making and printing workshops.

After the 1960s, the foreign-language printing factory in Beijing also started to build a gravure shop. Other provinces, autonomous regions such as Anhui, Guangxi, Shandong, Sichuan, Liaoning, Hubei, and Shaanxi, which have undertaken color printing tasks, have also installed gravure plates and printing equipment. In this period, the People's Pictorial, the Pictorial of the People's Liberation Army, and local pictorials of some provinces and autonomous regions mostly used gravure printing, which produced a lot of beautiful pictures.

Photogravure is a copper drum type, so gravure printing is a round of transformation printing. In order to remove the excess ink on the blank area of ​​the gravure cylinder, after the plate cylinder is provided with a doctor blade and the plate cylinder "eats" the ink, during the rotation, the excess ink on the plane is scraped off by the doctor blade. The ink in the recessed mesh pit is retained, and these inks are transferred to the substrate under pressure. Unlike gravure printing and embossing, gravure printing and embossing are based on the coverage of halftone dot area per unit area. The photogravure is used to represent the thickness of the ink layer in the web pit. The shades of tone are so profound that the photogravure prints are colorful and richly layered and expressive. Although its plate making process is complicated, its technical difficulty is high, its plate making cost is high, and its equipment investment is high, it has won people's favor with excellent printing quality.

By the mid-1960s, gravure printing had developed into its prime period, but it was not a long time. During the years of the "Cultural Revolution," the publishing industry was severely crippled and many graphic magazines ceased publication. The entire color printing industry was sluggish, and the gravure features were not displayed. The gravure printing began to be neglected.

After the "gang of four" was smashed, China implemented a policy of reform and opening up. The development of economic and cultural undertakings has enabled the printing industry to flourish again. However, when the time went by, the past gravure printing, which was known for its color printing, only found that the original printing of the younger brother had quickly become the “big boss” of the printing family. Not only did it occupy the letterpress printing on the printing of texts and books. One place is that in the case of color printing, high-end prints such as pictorials and pictures traditionally printed in gravure are increasingly being replaced by plain printing. In addition, the gravure printing equipment is heavy, the plate making cost is high, the electroplating pollutes the environment, the volatilization of the organic solvent in the gravure printing ink, and the health of the human body are hindered, which makes the gravure printing industry much neglected. In the mid-1980s, the gravure printing of book and book printing factories in most regions was often under the condition of “fishing in three days and drying in two days”. Some gravure printing equipment simply shuts down and goes out of business.

Gravure printing inks are benzene solvent inks. When they are printed on a substrate, they rely on the evaporation of the solvent in the ink. In order to improve the working conditions of gravure printing workers, there are generally suction devices on the gravure printing machine. Even so, the gravure printing workshop is always filled with strong irritating odors. In the 1970s, some printing plants in Beijing and Shanghai had tried water-based inks instead of benzene-solvent inks. Due to the lack of satisfactory results in ink transfer, drying, etc., the air pollution problem in gravure printing plants is still an obstacle to the further development of gravure printing technology.

The revitalization of printing> Third, the promotion of electronic engraving gravure printing

Since the 1980s, with the development of the national economy and cultural undertakings, packaging and printing has become the fastest growing field in the entire printing industry. The consumption of various flexible packaging plastic bags and plastic boxes is increasing. Like plastic films, paper-plastic composite packaging materials are different from paper. These materials have no permeability on the surface, and only the volatile dried gravure printing ink is suitable for printing on these materials. At this time, although the gravure printing has been neglected in the printing of books and periodicals, plastic gravure packaging, interior decoration, daily calendars and other plastic film printing, gravure printing has found a broader field of display. According to a survey of the packaging and printing industry in 45 cities across the country in 1981, 302 gravure printing machines were installed, while only 36,000 gravure printing machines were published in the same period. The two kinds of gravure printing are different due to the different materials used in the printing, and the structure of the machine is also completely different.

From the gravure printing technology itself, the electronic engraving gravure instead of the photographic gravure, just like the lithographic electronic separation technology instead of the photographic separation technology, has also added vitality to the development of the gravure printing.

With the advancement of the gravure platemaking technology, there is a large demand for gravure printing products on the market. These internal and external factors all provide a good opportunity for the development of gravure printing technology. For more than 10 years after the 1980s, there have been more than 200 gravure printing lines introduced in packaging printing.