How to ensure the smooth progress of book printing?
How to ensure the smooth progress of book printing and the consistency of the ink color of the printed product?
Gravure printing is the most commonly used printing method in flexible packaging, and its quality is directly related to the expressiveness of the product. In production practice, many problems plague the soft package factory, but in fact, gravure quality control is a rule to follow. The basic principle of the four major elements of the gravure printing machine is precisely this printing method. The structure and operation of the printing machine determine the quality of the printed matter. The four major elements are: doctor blade, embossing rubber roller, ink supply system, drying Dry box, the characteristics and basic principles of the dry box are described below by printers in China: the scraper can only print good products by scraping off the excess ink on the non-printing surface of the oil type. If you want to scrape the excess ink clean, without smearing, ink running (color running), and cutting lines, you must properly adjust the hardness, height, and angle of the squeegee.
The usual experience tells us: First of all, the hardness of the scraper device should be moderately flexible. The squeegee is placed at an appropriate height. The squeegee is placed at an angle to fit the angle. The hardness of the embossing rubber roller and the pressure of the embossing rubber roller directly affect the amount of ink on the printed matter. The hardness of the material of the embossing rubber roller affects the amount of ink applied. The material of the rubber roller is hard and the ink volume is small, and the material of the rubber roller is soft and the ink volume is large. The pressure of the rubber roller is large, and the ink volume is large. The pressure of the rubber roller is small, and the amount of ink is small. The pattern of the printing plate is deep, and the material of the embossing rubber roller needs to be harder; the pattern of the printing plate is lighter, and the material of the embossing rubber roller needs to be softer. Faster printing speed requires a harder material for the embossing rubber roller, while a slower printing speed requires a softer material for the embossing rubber roller.
To ensure the smooth progress of book printing and the consistency of the ink color of the printed matter, the ink supply system of the printing press must have a good circulation, and the ink must be kept in constant flow at all times. Always maintain the consistency of ink viscosity, measure regularly, and add solvent regularly. The old and new inks should be mixed in proportion to use. Use compound solvents. Prevent the imbalance of the ink components, precipitation and anti-coarse phenomenon. It is best to use an ink pump and a stirring rod for ink circulation. Note that the ink tank should not be too large and the ink tank size should be moderate. Drying box Drying box is one of the keys to increase the printing speed. It is the effect of the oven. The ink is dried by hot air, not by heating. The higher the heat, the less likely it is for the ink on the printed matter to dry. First, if the temperature is too high, it will cause filming on the surface of the ink. Causes the false dry atmosphere that does not dry inside the surface. Secondly, the low boiling point solvent in the ink volatilizes prematurely, the high boiling point solvent remains, and the drying speed slows down. The drying oven is required, the temperature is 40-50 degrees, the wind cannot be directly blown on the film, the heat cannot be directly baked on the film surface, it must have good ventilation, and it must not run on the printing plate and the ink tank. The dry box has better performance of secondary air return. It is necessary to effectively prevent false drying of printed matter.
Where does the high and low printing speed of the printing press come from? First of all, it is determined by the length of the transfer distance between the colors of the printing press. The longer the transfer distance between the colors, the higher the printing speed. On the contrary, it is difficult to increase the printing speed. Secondly, the effect of the drying box determines the printing speed. Because the front color is not dry, the back color will bite off the front color, causing color eating. Therefore, a good drying box must have the above-mentioned characteristics, the wind is greater than the heat, the wind cannot be directly blown on the printed matter, the wind cannot be run, the exhaust air is smooth, and the secondary return air performance is better.