(5) Non-coated paper
The surface is rough and has irregular pores. If the paper is printed with electrostatic dry powder imaging mechanism (mostly without wood pulp paper), the text and lines are also falsified. The density in the field does not meet the requirements, and the image clarity is not high. The solution is to use liquid ink as much as possible. The liquid ink can adhere to the surface of the paper and does not fall into the capillary pores of the paper as the solid toner does. However, the ink film formed by the liquid ink has poor adsorption capacity and the formed image ink layer has low fixation fastness. In order to solve this problem, a layer of rubber can be coated on the surface of the paper.
(6) Paper moisture content
Digital printing paper is very sensitive to the environment. In the electrostatic dry powder imaging Wei, toner fixed to be heated to 120-150 °C at the same time the paper to lose moisture, under normal circumstances the relative humidity of the paper from about 50%, reduced to 15% to 20%. Due to the loss of moisture, the paper becomes brittle, flounces, and breaks or tears easily during folding. In order to solve this problem, a paper with a relative humidity of 30:6 must be prepared for the printing system or the paper should be fed under air conditioning.
(7) Production process requirements
The production of digital printing paper is generally done by mixing bleached broad-leaf wood-kraft pulp with bleached broad-leaf wood Kraft wood pulp. The resulting paper has good strength, opacity, bulk, stiffness and whiteness. Degree, and uniform organization, the surface of the paper is smooth and clean, there is no fiber spot and dust, no lint, powder, good optical properties and printing performance. In the manufacturing process, it is generally necessary to add certain fillers, such as precipitated calcium carbonate.
Digital printing paper adopts neutral papermaking and neutral sizing technology, and correspondingly uses a variety of chemical additives. For non-coated inkjet printing paper, a reasonable choice of sizing agent can achieve different results. Retention aids are another common auxiliant in the production of digital printing paper, but the amount is not suitable, often affect the formation of the paper. For papermaking with recycled fiber pulp, starch or synthetic resin enhancers may be used to increase the strength of the paper to compensate for insufficient fiber strength.
Digital printing papers are mostly small-size papers, and require high fiber bonding strength, cleanliness, and both sides of the paper surface. The paper machine should use advanced top web formers to minimize the two sides of the paper. Soft calendering should also be used to obtain good smoothness. In order to prevent the paper surface from falling hair and entraining burrs, debris, paper scraps, requires a sharp edge of the paper blade.
Development of digital printing paper
1. Expand the range of substrates
At present, web digital printers can print a variety of substrates such as uncoated paper, coated paper, polyester, transparent paper, labels, and films. The expanded range of substrates will undoubtedly allow users to broaden the scope of their printing business after purchasing digital presses.
In fact, these choices are limited. Digital printers are still cautious about using new materials. The equipment dealers advise users to use some of the products of high-end paper companies, and most printers only use the products of certain specific paper manufacturers. At present, digital printer manufacturers usually conduct substrate suitability tests before identifying substrates, and wholesalers sell these substrates only after receiving their approval. After the technology in the paper market is mature, digital press manufacturers do not need to do these experiments again, which can save costs.
2. Improve the suitability of paper
It is understood that HP1ndigoE-Print1000SR format double-sided printing paper quantitative 100 ~ 340g/m2, XeikonDCP/500D digital press printing paper format for the 50 ~ 110cm, the basis weight of 80-270g/m2 these papers look the same surface , but its performance is not the same.
HPndigo. The use of liquid ink, the surface of the paper to meet the liquid ink transfer requirements, otherwise it may cause part of the picture is not printed, or part of the picture is very easy to erase. Therefore, special paper types are required for a specific digital printer.
3. Reduce paper prices
General digital printers have a small amount of paper stocks. In most cases, they place orders or contact with wholesalers according to user needs, and deliver goods the next day; the print volume is not large, and they are generally around 500 prints. Since the cost of paper accounts for only a very small part of the entire digital printing cost, users are not particularly concerned with the price of paper, and they place more emphasis on the reliability of the supplier. With the increase in paper usage and the deduction of manufacturers' R&D expenses, the price of digital printing paper is expected to further decrease.
From the printer's point of view, users are now only willing to buy paper from stable digital printing paper suppliers. Therefore, the digital printing paper market is not optimistic. Over the past few years, the digital printing paper market has been growing. As printers always purchase digital printing papers at high prices, wholesalers will become more and more interested in this market and provide more products.
At present, many large paper manufacturers in the world are committed to developing suitable papers for different printing presses, and new products will be printed on different devices to continuously improve and improve the performance of paper. The majority of manufacturers of digital printing presses also actively experiment with various substrates to ensure that the models they produce have a good printability for paper. At the same time, they also adjust the operating parameters of the press according to different papers in order to achieve good results. Print quality and work with paper manufacturers to develop new paper projects.
With the development of digital printing presses and digital printing technologies, China’s demand for corresponding substrates will grow even more, and better solutions will be obtained for the printing pressibility of digital presses and substrates, making digital printing possible. The quality is more perfect. For paper manufacturers, we should learn from the advanced experience of foreign countries, increase the research and development of digital printing paper as soon as possible, and gradually occupy a certain share in the market.