Paper Skills for Different Image Forms in Digital Printing
Digital printing has been well-known and widely used for nearly 20 years. As the development of China’s paper industry in the field of digital printing paper is seriously lagging behind, so far, people still rely on exploration in the choice of digital printing paper. Either they don’t know much about professional paper, or they are looking for alternatives to traditional printing paper. .
Paper is generally divided into two types: coated paper and uncoated paper. Coated paper is coated with a layer of paint on one or both sides of the base paper to make the paper have good optical properties and printing performance. Common coated papers include coated paper, white cardboard, digital coated paper, digital offset paper and inkjet paper, etc.; common varieties of uncoated paper include (electrostatic) copy paper, offset paper, color laser paper, and pure paper And light offset paper, etc. Whether the paper is coated or not, the whiteness, evenness, stiffness and bulk of the paper all affect the printing adaptability and post-press effect of the paper.
At present, digital printing is mainly divided into two categories: inkjet printing and electrostatic imaging according to the imaging principle. These two types of printing forms have different paper requirements due to different principles. So, how to choose digital printing paper? This article will analyze the above factors from the perspective of market application.
N1 inkjet printed paper
You can think of inkjet printing as drawing ink-splash paintings, but the ink droplets "spattered" are very small, at the level of picoliter. Since it is an ink droplet, smudging will inevitably occur on paper with strong water absorption, which will affect the printing effect and sharpness. At this point, it is not difficult to understand as long as you have had the experience of writing calligraphy with brush or pen. Therefore, professional inkjet printing paper is a kind of coated paper with special coating, which has the characteristics of quick-drying, waterproof, and good color reproduction. Due to the different inks used, we divide inkjet printing into UV inks and water-based inks. Below we will look at the paper requirements of these two inks. UV inkjet printer is a printer that combines UV curing ink and inkjet technology. It relies on high-speed polymerization and curing of photopolymerizable ink to complete printing. It has fast curing, adapts to a variety of substrates, is not easy to block the nozzle, and the ink is stable. And the characteristics of good printing quality, common in the market, such as Kemei KM-1, not only has low requirements for paper, but also adapts to printing on a variety of substrates and substrates of different thicknesses except paper. Therefore, the traditional printing of ordinary paper, Whether it is coated paper or uncoated paper, it can meet printing requirements. The inkjet printers using water-based inks are currently mainly high-speed inkjet web printers, such as Founder Jieying series inkjet printers and Shengde 1200 inkjet printers. Since water-based ink uses "water" or "a mixture of water and organic solvent" as the carrier, the substrate must absorb water during printing. Therefore, this type of printing machine should use special coated paper or coated paper treated with special additives in the papermaking process for printing. Commonly used papers include digital offset paper, digital pure paper and digital light offset paper, but coated paper and digital coated paper are not recommended. At present, inkjet web printers have been widely used in publications and commercial black-and-white printing. In the second half of the year, color inkjet printers will come out one after another, and the requirements for paper will be higher.
Comparison of digital printing effects on different papers
Detail comparison chart
N2 Electrostatically imaged paper
Electrostatic imaging is one of the earliest ways to realize digital printing, and it is also the most widely used printing method in the graphic market at present. Electrostatic imaging uses the principle of laser photography. The imaging agent is toner. After the toner is imaged, it is fixed by high temperature and high pressure to solidify the toner on the surface of the substrate.
Affected by the high temperature and high pressure environment in the printing process, the printing paper needs to be able to withstand high temperatures. Therefore, in the paper selection, the use of coated paper is more cautious, especially the coated paper. It is recommended to use professional digital printing coated paper, and uncoated paper. The surface of the paper is not covered by paint, the surface of the paper is in an open state, the conditions for the loss of water in the paper are better, and the adaptability to electrostatic imaging is also better. Copy paper is the earliest paper produced for this printing method. In fact, it should be called anti-electrostatic copy paper. The paper is not easy to generate electrostatic adhesion during the printing process, causing paper jams, which can achieve high-speed printing and improve production efficiency. Reduce the loss, at the same time, the moisture control of the paper is low, and the flatness after printing after high temperature and high pressure is good.
N3 electronic ink printing paper
HP indigo printing machine uses electronic ink, which organically combines static control technology and printing ink technology. While retaining the gorgeous color and printing adaptability of ink printing, it realizes the digital control of ink, and then through color transfer Technology and hot offset printing technology transfer the ink to the substrate. The electronic ink completes the drying process through two ways of penetration and volatilization. This drying method is basically not affected by the surface conditions of the paper. The commonly used digital art paper, offset paper and special paper can achieve good printing results. However, the hot offset printing technology of indigo printers is different from traditional cold printing. Some coated papers will have blistering and poor ink absorption during the printing process, so the paper selection needs to be treated with caution.
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