Application of thin plate technology in printing

Corrugated board preprinting and postprinting (direct printing) are undergoing drastic changes. Monochrome printing has been replaced by a variety of colorful prints, and the common washboard phenomenon in corrugated printing has also been effectively improved. The cardboard weight of corrugated cartons is getting higher and higher, the enamel type becomes finer, and the surface flatness is getting better and better. The carton is further playing the role of packaging and enhancing the attractiveness of the interior products. Manufacturers of printing machinery, corrugated board, anilox rollers, inks and plates have made positive contributions to the development of corrugated printing.
As early as the early 1990s, thin-plate technology was already being promoted in the carton processing industry to improve the quality of printing after corrugating. This technological trend has caused a rapid increase in the quality of printing and a substantial reduction in costs. Halftone effects have become commonplace in corrugated paper printing. Processors often print UPC bar codes on paperboard. Advances in board production, improved ink quality and anilox roller technology have also made thin plate technology truly successful.
First, demand driven supply In corrugated printing, many different types of plates are involved, resulting in a diverse mix of plate types, plate thicknesses, adhesive tapes, and liner materials. But the standard has not yet been established, which makes corrugated printers face many uncertainties in the surface structure of the plate, pressure absorption, ink transfer characteristics and field effects; many processors have tried different types of plates, viscose Ribbons, liner materials, and inks are associated with different print results.
While processors are doing everything possible to find ways to meet the printing requirements of various paperboard materials, the need for a standard printing plate system is becoming more and more urgent.
For a long time, corrugated printers have been looking for a specific plate material that can be easily processed without being limited by material properties; images can be processed on any plate making equipment in tropical, subtropical or continental climates. In response, a new type of polyester structure material came into being; in a variety of climatic conditions can provide a stable head time, even after millions of India ink delivery tends to be consistent. The customer's demand for versatile printing capabilities has strongly promoted the development of thin corrugated plates.
Recently, digital plate materials have also become an important issue for corrugated printing. Newer and thinner plates continue to emerge; the Sensi-Live black mask on the plate can be ablated in a CTP laser device, resulting in a more comprehensive printing effect.
The trend is toward digital imaging, while at the same time providing customers with optimized print quality. In order to open the market, plate suppliers increased the number of plate sizes and specifications. The new thin/soft sheet-fed polyester version became a mature representative of this type of product. Now thanks to the superior ink transfer and halftone effects of the soft version, even cardboard prepressors have turned their production from harder plates to soft plates. Plate processing time is reduced, which also shortens the printer's pre-press preparation time and saves material and process costs.
Second, to overcome the "seesaw board" effect and network overflows in the corrugated flexo, in order to overcome the "seesaw" effect often have to increase the printing pressure, resulting in an increase of outlet overflow. Excessive plate deformation can cause web stickers to increase, reducing printing quality, and can only reproduce coarse screen effects and large areas of whitening. In order to reduce the amount of deformation, the thin plate technology has taken an important first step in the direct quality of corrugated printing.
The second step is the development of new polyester materials to achieve a standardized printing plate system. In the past few years, this kind of printing plate has already appeared in the market, and the continuous improvement in exposure latitude also makes the thin version become the first choice for obtaining high-grade corrugated printing.
Third, pre-printing and post-printing. Whether it is pre-printed or post-printed, a thin plate with a hardness of 32 to 34 shores (Shore) can meet the requirements for corrugated board printing. This type of plate is designed for multi-color half-tone printing and can be used to reproduce both the thread and the solid manuscript on any paper or cardboard. After the main exposure, there is a strong color change in the exposed and unexposed areas of the plate. This makes it easy to control the exposure quality of the entire corrosion area.
The advantages of the new polyester version also include: higher ink hiding power (even for various rough-surfaced boxboard, paper bags, and carton board materials), fine single-spot element reproduction, fine reverse-white effects, and UPC barcode money bars Etc.: If the printing plate is processed under standard conditions, its range of adjustment is very wide and can be optimized. The long exposure width is also a big advantage of the new polyester material.
The corrugated board becomes finer. From F楞, E楞 to N楞, G楞, at the same time, bright colors are required for printing. The demand for excellent ink coverage and contrast is also growing, and printers are turning to thinner technology. The technical demarcation line between corrugated board printing and folding board printing is less obvious.
Fourth, choose the appropriate plate plate manufacturers have to adapt to changes, to meet the requirements of halftone printing to reduce network overflow, optimize ink delivery, and further weaken the "seesaw" effect and strengthen the contrast contrast and other diverse needs. Fine halftones and linework require a stable plate base. This type of job recommends the use of a new thin/soft plate or other thin/slightly hard standard plates. Plates must have high resilience and deformation resistance.
The use of a compressible cushioning material is also required when using thin plates. The bubble cushioning material absorbs excess printing pressure and reproduces a sharp and sharp mesh. This makes it necessary to adapt the type of printed corrugated board to the pressure of printing, and the requirements for the thin and hard 楞 (E楞) and thick and soft 楞 (B) types vary.
The correct "plate liner" combination needs to be tested, depending on the undercut of the cylinder and the type of corrugated cardboard and stencil, the thin plate has a shorter processing time, and the amount between the film and the plate Also smaller, the thin plate is etched less than 0.039 inches because the slightly larger printing pressure may cause the fine anti-whitening area to be contaminated. This is precisely why the thin plate technology for corrugated printing is used, and the reason why the base plate is recommended to be 0.039 to 0.043 inches.
5. Select anilox roller Anilox roller is used to ink the printing plate. When selecting, it is required to handle the fine halftone color screen sticker, to improve the ink transfer rate from the printing plate and to adapt to the ink with stronger coloring power.
The following anilox rollers can be used for different grades of corrugated board printing:
B, coated paperboard: It is recommended to use 356 money per inch of the anilox roller, theoretical ink transfer volume 4.20-4.52BCM (6.5-7.3cm3/m2) to achieve the best half-tone, purlin effect;
B. Uncoated paperboard: The ink transfer is largely affected by the plate hardness and the combination of the plate liners. Recommended 305 lines per inch, theoretical ink transfer volume 5.18-6.13 BCM (9.0-9.5) E楞, coated paperboard: different types of plates, the impact of plate hardness and plate gasket combination is the key to the printing of these materials, Therefore, it is generally recommended to use an anilox roll with a theoretical ink transfer amount of between 356 and 405 RMB and a theoretical ink transfer amount of 3.23-4.52 BCM (5.0-7.0 cm3/m2).
In addition, the ink composition and viscosity have a great influence on its transmissibility. When choosing a printing plate for any printing method, it must be clear that the interaction of various components in the system affects the printing plate, the cushioning material, the inking roller and the ink itself are also very important. So carefully selected materials will result in consistent and successful jobs.
When the printing pressure is too low, the printed substrate is susceptible to corrugated and washboard-like patterns, as well as affecting field and fine line printing. When the printing pressure is too high, the printed substrate is easily deformed or even damaged, and at the same time, the resin plate is deformed and the printing dots are enlarged.