Bags on the covering power of white ink, black ink not enough?

When a lot of packaging printing, need to use white ink, covering power is not enough, but the white ink and some need to use black ink printing, full covering power also not enough. The two problems, a professional flexible packaging producers packaging think to deal with similar problems, need from the main factors affecting ink covering power, such as: ink concentration of color, ink layer thickness, from three aspects, such as pigment dispersion and the corresponding test analysis. 1, improve the concentration of ink color ink color ink concentration is increased hiding power, one of the main method used in printing, the special configuration of titanium white ink color ink concentration of 55% ( The general white ink was 25%, the titanium white pigment is now the most white, covering power of the best white pigment) , after printing, the hiding power is better than general white ink, but is still not reach requirement, due to the high concentration of color, less solvent, monotonous is fast, easy to cause plugging version, printing ink flow property is bad, after pulverization occurs, so other methods should be considered. 2, ensure the ink layer thickness standards as we know, intaglio printing ink layer thickness can be up to eight 15μ M, but assumes that only 3 - white gravure ink layer 4μ M not meet specification, can be a problem. Can from the following several aspects. 1. Edition version of drum drum production suppliers engraving depth has reached maximum ( 60μ m) , but due to its technical limitations, carved net hole is sprayed and sprayed net hole to cause ink transfer condition, blocking version so while increases the storing ink but does not increase the amount of ink quantity, and at this stage in order to better transfer ink, mesh point should show trustum of a pyramid shape or blown out, both in the shape of a mesh point store large amount of ink, the connotations of ink. In addition, the mesh point on the edge of the smooth degree and the chrome plating thickness also affect the ink transfer, so can consider to print two methods to deal with problems caused by version of the drum. 2. Embossed substrate soft rubber roller's hardness is too big, too little cave in the net of the ink transfer, should change the hardness of the soft embossing roller. 3. Printing pressure is small cave in the net of ink transfer by extrusion small bad, should improve the stamping force at this time. 4. Thin film after surface treatment of storage time is too long cause wet ink adhesion of poor, so should be in the substrate surface treatment after printing in time. 5. Ink pigment concentration is too large in dry too fast, the influence on the ink, should adjust the pigment concentration and viscosity. 6. Should be considered when printing membrane electrostatic is too large to eliminate static electricity, device after electrostatic increase ink transfer rate. 7. After selection of the above methods considering the performance of the printer problem printing, printing ink ink film thickness was increased obviously, but still not reach the expected demand for white ink and hidden, so to consider the gravure printing ink itself once again. 3, control the dispersion of pigment ink covering power essentially depends on pigment refractive index and the link is the ratio of the refractive index. When the ratio is 1, paint is transparent; If a ratio greater than 1, the pigment is not transparent, which has the covering power. The refractive index of pigment pigment dispersion and the influence of pigment and link material refractive index difference. The higher the pigment dispersion, the smaller the difference, the transparency of the pigment, the better. Test for titanium dioxide with white ink pigment. Titanium dioxide is a white crystalline powder, none of the white pigment, which is not lit, the refractive index of 1. 84 - 2. 55, dispersion is large, light fastness, good heat resistance and alkali resistance. Other printing method using ordinary paint, thinner and ink layer and low concentration can achieve the required cover effect, but not gravure. Gravure printing ink pigment particle size should be less than 5 & mu; M, and gravure printing ink than other ink printing method are rare, so the dispersion, high transparency, The covering power is low) 。 Assumes that the use of titanium pigment particles is small, large dispersion, will cause the hiding power is not strong. If the granularity is increased by still can't achieve the desired effect are covered, can switch to other printing method. If properly increase the size of titanium dioxide are used to configure the printing ink, white ink covering power has increased, this method is better than increase the concentration of ink color and ink layer thickness, of the save Labour when the province at the same time also can reduce the production cost.