Coated printing paper is a coating liquid which is mainly composed of auxiliary solvents such as pigments, adhesives, tackifiers, fluorescent agents and lubricants. After drying, it is smoothed to make the paper have good optical properties and printing adaptability. Mainly used for printing magazines, books, trademarks, packaging, catalogues, etc., is currently one of the most commonly used paper types in cultural publishing, advertising design, printing and binding, and industrial and commercial circles. Because of its smooth surface and good whiteness, coated paper is generally used for multicolour printing. Coated paper base paper is generally multi-purpose woodland paper, but also coated paper containing ground wood pulp or deinked pulp base paper.
Coated paper is classified by the amount of coating. According to the amount of coating, it can be divided into copper plate paper, coated paper, lightweight coated paper and micro-coated printing paper.
Many functional properties constitute the basic component of paper, which determines many properties of paper. Here we call it functional properties: cellulose is white, so paper is white, unless it contains lignin impurities or dyes to give it color; cellulose is easy to absorb water, so paper also absorbs water, printing. Brushing paper has to be specially treated to reduce its water absorption capacity to prevent soaking; cellulose absorbs moisture, so paper absorbs moisture, and it absorbs or releases moisture in the air with the change of relative humidity; non-coated printing paper has many disordered structural elements, which are both longer and shorter in the composition of paper. Fibers of different origins include fillers, adhesives, dyes and various additives. Due to the different varieties and processing methods of fiber materials, their structures and properties are also different. Fillers and rubber also have different functions because of different varieties.
Non-coated paper is different from coated paper in printing time. Take the previous experience of small edition as an example, customers need to use art paper in printing desk calendar, while small edition is coated paper in digital proofing. In formal printing, I forget in detail that the color of digital proofing is better than the tradition. Printed, wait for the time of printing suddenly very dark color, the ultimate reason is in the paper, but at that time the number and size of customers is not very large, immediately found on the printing, immediately stopped, did not form a great loss, Xiaobian is also a long-term wisdom. Digital printing ink is only on the surface, so the color is very bright.
Most structures of non-coated printing paper have two-sidedness, that is, the difference of the two-sidedness of the sheet depends not only on the anisotropy of the distribution of the structural elements mentioned above, but also on the difference of the two-sidedness of the paper.