The Origins of Printing

By: ZHENG YIMIN Published at: 01/11/2022 08:52:24

Ink balance, a hydrophilic blank, and ink-friendly graphics (only refers to offset printing)

1. Water-oil compatibility

The molecular structure of water molecules with moderate polarity differs from that of non-polar oil molecules, prohibiting water and oil from attracting and dissolving each other, according to the chemical concept of similarity and compatibility. This rule is in charge of creating the flat printing plate. Water might now be used to distinguish between text and blank spaces.

2. adsorption on the surface

It has the ability to absorb different substances based on surface tension, enabling image and text separation in lithographic offset printing.

3. dot pattern

Because offset printing plates are flat, the thickness of the ink cannot be employed to express the layers of images on the printed matter. It creates intricate visual layers.

A wet surface is not easily affected by oil, therefore water and oil are constantly diametrically opposed. Because the offset printing plates are almost on the same plane, a solution for successfully separating the blank and graphic sections must be devised. Water's role in offset printing is referred to as "water and oil incompatibility." During the printing process, a thin layer of water is uniformly coated on the surface of the printing plate (the graphic section will not be wet due to the selective adsorption of the printing plate's surface) and then coated on the printing plate. The blank region is successfully protected when ink is applied to it.

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