Problems to be Considered When Applying Spot Color Inks for Offset Printing

Problems to be Considered When Applying Spot Color Inks for Cigarette Packaging Offset Printing

In offset printing plants, trichromatic inks (cyan ink, magenta ink, yellow ink) and black ink are generally used for printing, but they cannot satisfy the hue requirements of some texts, lines or large blocks, especially for the printing of cigarette packages. It is often necessary to print a variety of spot colors. Spot color inks are specially produced in many cases, and can be purchased directly when used. Practical production can also use tricolor inks or other spot color inks for deployment to obtain spot color inks of the corresponding colors. When transferring ink, it is necessary to use printing samples as the standard and consider the following issues:

(1) The hue of the ink conforms to the color sample standard of the manuscript. To determine the hue of the ink, first analyze the color of the print, analyze and synthesize the content of the original in the three primary colors, and determine the main color and the auxiliary color and the ratio thereof. At the same time, it is necessary to consider the nature of overprinting sequence, printing materials, primary inks, and auxiliary materials. In the deployment of hue, the auxiliary color ink must be gradually added to the main color ink until the color sample meets the requirements.

(2) The printability of the ink meets the objective conditions for printing. The viscosity, viscosity, and fluidity of the ink should be adjusted according to the nature of the substrate, machine speed, and graphic type.

(3) The amount of dry oil should be added correctly. The amount of dry oil depends on the temperature and humidity of the printing environment, the nature of the paper, the thickness of the ink layer, the amount of auxiliary materials added, and the performance of the ink itself. If the amount of dry oil is too small, the ink cannot be dried within the required time, and the printed product will produce sticky dirt; if the amount is too much, ink build plates and pile blankets will be produced, which will accelerate ink emulsification and cause problems such as pasting plates. Generally, the principle of dry oil consumption is: coated paper (coating paper) is more than non-coated paper; winter is more than summer; more ink is darker than dark ink; color sequence is higher in front of the ink than the color sequence. .

(4) The amount of ink to be formulated is appropriate, and the amount of ink to be formulated depends on the number of products, the area of ​​the image, the thickness of the ink layer, and the quality of the paper. Small batches of products must be refilled with enough ink at a time and not wasted (according to experience, the actual amount of ink dispensed should be slightly more than the amount of ink used for calculation). Large batches of products can be batched and distributed in batches, but each batch of inks must be clearly documented in order to ensure the consistency of the inks used before and after deployment.

Source: China Tobacco Packaging Ink Information Network