Is the Printing Speed of a Gravure Printing Machine Really Determined by These Two Factors?

The speed of a gravure printing machine is related to its structural composition. When a flexible packaging plant purchases a gravure printing machine, it may consider two factors and make a purchase decision only after examining them.

The printing speed of a gravure printing machine is determined first by the length of the transfer distance between the individual color units. Because during printing, for the registration of colors on the printed product, if the ink of the previous color has not dried, the ink of the following color will dissolve and pull off the previous ink, causing ink picking. Therefore, the longer the transfer distance between the individual printing colors of a gravure printing machine, the longer the natural drying time, and the more the printing speed can be raised; conversely, it is difficult to increase the printing speed.

Second, the printing speed is determined by the performance of the drying oven. If the drying oven performs well, the ink dries thoroughly and well; not only will the previous color ink not be dissolved, but solvent residue will also be reduced. Gravure printing ink is dried by blowing hot air, not by hot baking. First, gravure ink forms a film prematurely when exposed to heat, and the coverage of the color film affects the volatilization of the solvent in the ink, creating the phenomenon of false drying of the ink. Second, the ink contains multiple solvents with different boiling points, so the volatilization speeds of the various solvents differ; that is, low-boiling-point solvents volatilize quickly, while high-boiling-point solvents volatilize slowly. The higher the temperature, the faster the low-boiling-point solvents volatilize and the more high-boiling-point solvent remains. In view of the above two reasons, the greater the heating volume of the printing machine's drying oven, the harder it is for the printing ink to dry. False drying and non-drying of the printing ink can cause color bleeding or blocking of the printed product. Color bleeding or blocking of the printed product prevents the printing speed from being run fast; when the printing speed is slow, the amount of ink applied must be large, which easily causes color bleeding or blocking of the printed product, and so on, making it difficult for the printing speed to increase.

Therefore, the ratio of heating volume to blowing volume in the printing machine's drying oven must be correct; this is the prerequisite for ink drying. Second, if air blows onto the printing plate in the printing machine's drying oven, the printing ink will dry on the printing plate roller, the light screen areas of the printed pattern cannot be printed, and gradient colors will also be printed incompletely. Third, if the heat of the drying oven is directed straight onto the film, the film will stretch as a result. If the air is directed straight onto the film, the film will flutter. Film stretching and fluttering will affect the registration accuracy of printing.

When selecting and purchasing a printing machine, note that a good drying oven for a gravure printing machine should have the following: heat must not be directed straight onto the film surface; air must not be blown directly onto the printed material; air must not blow onto the printing plate; the blowing volume must be greater than the heating volume; exhaust must be unobstructed; and secondary return-air performance is even better.