Application of CTP Technology in Flexo Printing

Since the concept of CTP (Computer-to-Plate) technology was proposed in the 1980s, the CTP system was exhibited at the drupa printing exhibition in 1995. There have been many reports on CTP reports and professional papers or applications, but most of them are about offset printing. CTP system. Flexo is one of the main methods of packaging printing, because of its fast printing speed (die cutting, indentation, etc. can be processed in a machine), low cost, wide range of printing and more and more attention by packaging companies, but CTP is There are not many reports and papers on the application of flexographic printing. This article discusses the application of CTP in the software version and its development in foreign countries.

I. Today's CTP

Flexographic plate makers agree that the market share of CTP is steadily increasing, but authorities do not agree that CTP has the potential to dominate the flexographic market.

In the flexo market, Babel, the marketing manager of MacDermid's printing solutions, said that the current market share of CTP is less than 5%, but the digital platemaking system has a momentum of rapid growth. Its profits are indeed high, and companies are increasingly concerned about digital processes and digital plates.

Plate makers and suppliers have been paying attention to maintaining the rapid growth of the CTP plate-making market for additional research and development funding. Robert, a technology manager of RBOor, a distributor of plate-making equipment and photosensitive resin, believes that the new CTP technology is in the final test. In the phase, it is expected that flexographic printing machines using digital flexographic plates will be available at the end of this year.

Digital salesman of traditional flexo maker Asahi Kasei recently introduced a digital flexo for various widths of rotary printing, and plans to introduce its digital crepe version this year (with small wrinkles in digital dots, With a subtle level of detail, the image will be finer. Jim Wright, general manager of JV Graphics Systems, said: "From the percentage point of view, it is a little small, but by the end of the year, the digital flexo will be closer to 25% of our total output."

Some companies have found that the investment in research and development on the CTP is profitable. Roy Paddle, DuPont's marketing manager, said that DuPont's digital imaging company's digital flexo version saves one hour compared to the traditional photolithographic process, which has aroused great repercussions. Budweiser commented that DuPont's digital flexo sales have a good momentum of development. By the end of 2003, pre-success digital flexo sales accounted for 40% of the company's flexo business.

Thomas Frater (executive president of AKL Flexo Tech, whose North American headquarters is based in Cumberland, RI) stated that “as the time to market is reduced, low-cost transport packaging, improved accuracy, and improved overall print quality, the future of packaging CTP is a modern technology."

With the growth of CTP sales, Bedewell has every reason to believe that there is a high expectation for the future of digital plate making. According to the current growth rate, it is expected that the digital flexo will become the main method for North American flexible packaging and label printing in the next 2 to 3 years. However, Budweiser's optimistic estimate does not represent the views of industry insiders. Tom Carsonella, production manager of MacDermid, believes that CTP will not become the main method of plate making. Carsona acknowledged that the market's demand for digital products has become stronger, but the major percentage of the print service market not only requires high-quality images that digital plates may provide, but also does not take into account the cost of using CTP plates. Line art and dot art graphics in the market, such as bread bags, cardboard, fast food paper cups and cartoons, may use digital technology, but most products do not require high quality images. CTP may not be the first choice for these products.

Second, the new technology of CTP

1. Engraving CTP Sleeve Version and Advantages The emergence and application of digital imaging sleeve technology will certainly further improve the quality of flexographic prints. In the folding cartons market, the competition between flexographic printing and offset printing and gravure printing is fierce. The digital imaging sleeve technology is very suitable for short-lived printing. It can directly transfer digital data to the plate to make printing plates and simplify, eliminating many intermediate links. These will promote the promotion and application of digital imaging sleeve technology in flexo printing. Such as the production of CTP sleeve version directly on the plate cylinder, this innovative technology further simplifies the plate making step and improves the printing quality of the CTP flexographic plate.

(1) Types of CTP Sleeve Plates

The BASF printing system is a laser image system specially developed by Stork STK for engraving images directly on plates. LEP (laser system for direct engraving of flexographic plate) is a new generation CTP technology that can provide high resolution and simple process. Tony Diwater, BASF's marketing and development manager, said: “The LEP version completely changed the flexographic platemaking method. Traditional platemaking requires six steps: front and back exposure, development, cleaning, drying, and finishing, and the entire LEP process is The unification is completed in one step, laser engraving can obtain accurate digital images, and the whole process does not use chemicals, reducing the pollution to the environment.

(2) The advantages of CTP sleeve version

Although flexo printing can achieve excellent image integrity, the printed image is always slightly different from the original. The root cause of this phenomenon is that the plates produced by the flexographic plates are flat, but they are printed in a circular manner. No matter how precise your plate, plate, and calibration device is, when you place the plate on the press or mandrel and align it, the material is easily deformed and resized.

With the development of computer-to-plate technology, the sleeve version was pre-loaded onto the cylinder and directly etched in a "circumferential" manner. The final printed image was exactly the same as it was when it was designed.

The CTP no longer exposes the photosensitive resin plate through the film. The advantage of electronic engraving on any flexible sleeve plate or plate is that it can avoid the use of film products resulting in loss of detail and contamination of the environment.

CTP has advantages not only in faithfully restoring manuscripts and reducing costs, but also in operating time. In principle, as long as the picture production is completed, the computer-to-plate system can directly generate engravings from electronic files—an installed plate. Once the engraving is completed, the plate can be printed - it does not have to be installed.

Seamless printing plate. In particular, printing with ten rolls of decorative paper does not like to have a plate joint on their products. For packaging manufacturers, it usually means that the joints must be folded into the seams during product design. It is a natural process to directly etch a 360-degree circular image on a seamless, pre-installed plate.

The ability to produce seamless plates reduces the advantages of gravure printing. With flexo printing's significant increase in quality in recent years and its advantages in running time and printing plate cost, potential customers will have no reason to choose gravure instead of flexo printing.

2. Other forms of CTP

Price is a major obstacle to considering entering the CTP market. The industry is looking for a cheap alternative to digital technology.

Cortron's high-definition flexographic precision exposure system provides similar digital image quality at a low price. Cortron's marketing and sales manager said: "Precise exposure adjustments to the exposure angle produced a narrower shadow like CTP. The dots obtained were very similar to those on the CTP, and the price of the precision exposure system was only $32,000."

Another - the choice is OLEC, a single point light source exposure system. Various sizes of plates can be used. The point light source exposes the unique high output of the conventional photosensitive resin plate to OLEC, and the point light source makes it possible to provide high-quality dots or images. If people are pursuing the quality of digitized images, using point light systems can achieve or even better than digital image quality at a very low cost. According to Bert Odoch, founder of OLEC, "The system's genius lies in its high copy quality, short imaging time, and predictable final image quality."

Third, the obstacles to the promotion and application of CTP

Digital platemaking has many advantages: it reduces plate-making time, the entire digital process eliminates the film, increases the predictability of consistency and quality, competes with offset and gravure in terms of quality, but costs may prevent CTP from occupying the flexo market. One of the obstacles.

First of all, the price of introducing CTP is about 500,000 US dollars. Although the price has dropped recently, it still needs 200,000 US dollars. Digital technology still requires high capital investment. Derek Keyes said that whether or not it can be afforded becomes a problem. For example, Kodak Color Image's worldwide packaging is partitioned. The CTP will become a platemaking standard, depending on the amount of funds that can be invested, as well as the cost-return rate for investing in printers, intermediate processes, and post-press processing.

The rate of return and the cost savings from eliminating the film and its processing can make up for the initial input and the cost of materials for digital platemaking is another issue. Boldwell said that CTP's future investors will do internal long-term planning first, but after the initial big investment, its return is also positive. On the other hand, RBCor's Kelsall disagrees with this view. He said: "The elimination of the film does save costs, but this savings was stifled by the increase in the price of digital media."

Fourth, the conclusion

With the application of CTP technology in the flexo version, the quality of printed matter is also constantly improving. High contrast, smoother tone, and lower dot gain rates have made the quality of flexographic prints more and more close to the quality of gravure and offset products. With the inherent advantages of flexographic printing, if the cost of CTP equipment and CTP plates can be reduced, the application of CPT in flexographic printing will have unlimited market potential.