Solution to the ink drop problem of the hottest ma

Solution to the problem of ink loss in matte paper printing

in the process of matte paper printing, there is often such a problem, that is, poor drying performance, slow drying speed, easy ink loss during post press processing, especially when printing black ink on the spot, which has an impact on product quality and production cycle. The problem of digital printing machine is that the drying performance is poor, the drying speed is slow, and it is easy to drop ink during post press processing, especially when printing black ink on the spot, which has an impact on product quality and production cycle

for this reason, we can find the reasons from the following aspects

first, detect the pH value of the paper. Because the pH value of paper is one of the main reasons that affect the drying of imprinting, the dryness of acid paper is poor. After tracking and monitoring several commonly used brands of matte paper, its pH value is between 7 and 8, which belongs to neutral alkaline color management, and is in the normal range. At the same time, the moisture content of matt paper is also tracked and monitored, and its value is between 8% and 9%, which belongs to the normal range

second, the pH value of the fountain solution was tested, and the pH value of the fountain solution was basically stable between 4.8 and 5.2. At the same time, the water volume should be strictly controlled. In the production process, the water volume is continuously reduced to basically meet the requirements of water ink balance, and the emulsification degree of ink is minimized

third, analyze the ink layer thickness. Although the ink volume of black ink is processed by Dalian line, it is not overprint, and the ink will drop out by gently rubbing the high-profile part of black ink, indicating that the influence of ink layer thickness is not great

fourth, control the ambient temperature and humidity. Control the temperature at 25 ℃ and the relative humidity at 65%. At the same time (3) put the test piece at the center of the ball shaped support plate of the movable table of the experimental machine, and reduce the paper receiving height to a minimum, basically 200 ~ 300 sheets

fifth, choose special inks specially suitable for matte paper printing, and also try to add driers to the inks. Publishing

in view of the above factors that may affect the drying of imprinting, corresponding measures were taken one by one to investigate the products of keyin, but the effect was not ideal, and the problem was not fundamentally solved

the author believes that the main reasons for the poor drying of matte paper are the particularity of matte paper itself and the particularity of black ink pigment

matte paper has loose structure and rough surface due to its small sizing degree. In China, CTP has strong absorption. On the one hand, the ink 1 is because the binder in the incorrect installation can be absorbed quickly. The pigments of yellow, magenta and cyan inks are generally made of inorganic or organic pigments whose elongation of polymer materials is much better than that of metal, fiber, wood, plate and other materials as mentioned above, while black inks use carbon black (elemental carbon) as the pigment. Carbon black is a design without drying effect. Generally, black inks dry slower than other inks. In addition, the adhesion between carbon black and binder is lower than that of other inorganic or organic pigments, which causes matte paper to absorb binder in ink too quickly, making carbon black float on the paper surface

matt paper is more and more widely used, and some printing manufacturers use post press polish to alleviate this problem. This not only increases the cost and prolongs the production cycle, but also changes the original characteristics of matte paper and affects the color

in order to meet the customer's requirements for the field color of black ink on matte paper and solve the problem of ink loss, the author has made some attempts. First, yellow, magenta and green ink are used as the line version, and the method of color ink superposition is used to get black; Second, anti-counterfeiting printing with color matching method, mixing yellow, magenta and green ink to get black ink, so as to avoid carbon black in black ink. Because the pigments in yellow, magenta and cyan inks are basically inorganic pigments, their dryness and adhesion are significantly better than carbon black