Printing plate four categories

Letterpress ink: A type of ink used in letterpress printing to print books, newspapers, picture albums, bills, accounts, etc. The main feature of letterpress printing is that the inked part of the printed page is protruding from the non-inked part. Letterpress ink according to the type of printing machine and the use of printing products are divided into lead printing ink, copper printing ink, rotary letterpress ink, flexible letterpress ink.

Lithographic ink: A type of ink suitable for lithographic printing. Each part of the lithographic printing page is basically in a plane, the pattern is oil-wet, the non-pattern is water-wet, and the principle of oil-water repulsion is used for printing, so the lithographic ink must have water resistance. According to the process, it is divided into offset ink, web offset ink, flat offset ink, waterless offset ink, iron printing ink, lithographic ink, collotype ink.

Gravure ink: a type of ink suitable for gravure printing. When printing, ink is inked into the patterned part of the page, erase or scrape the ink of the non-patterned part, and then print. There are engraving intaglio ink and photogravure ink.

Screen printing ink: A type of ink that is printed through the screen of the plate to the substrate surface. Screen printing ink is divided into stencil ink and screen ink.

Inks have different properties according to the binder used. There are mainly resin ink, solvent-based ink, water-based ink and UV curable ink. The use of organic solvents as ink binders will have a negative impact on the environment. In order to make the ink meet the requirements of environmental protection, environmental protection materials should be used as the ink binder. Environmentally friendly inks mainly include water-based ink, UV ink, water-based UV ink and some alcohol-soluble inks.

Water-based ink: The difference between water-based ink and solvent-based ink is that the solvent used is water rather than organic solvent, which significantly reduces VOC emissions, can prevent air pollution, does not affect human health, is not easy to burn, ink stability, bright color, no corrosion plate material, simple operation, cheap price, good adhesion after printing, strong water resistance, rapid drying, Therefore, it is especially suitable for food, beverage, medicine and other packaging printing materials, is the world's recognized environmentally friendly printing materials, and is also the only printing ink approved by the United States Food and Drug Association.

Ultraviolet curable ink: Ultraviolet curable (UV) ink refers to the ink that uses different wavelengths and energies of ultraviolet light to make the ink film and dry under ultraviolet irradiation. The use of different ultraviolet spectra can produce different energies, and the monomers in different ink binders can be polymerized into polymers, so the color film of UV ink has good mechanical and chemical properties. The main advantages of UV ink are: (1) no solvent; (2) Fast drying speed, less energy consumption; (3) Good luster, bright colors; (4) Water resistance, solvent resistance, good wear resistance. UV ink photoinitiator is a compound that is easily excited by light, excited into free radicals after absorbing light, and the energy is transferred to photosensitive molecules or photocrosslinking agents, so that UV ink photocuring reaction occurs. UV ink has become a more mature ink technology, and its pollutant emissions are almost zero. In addition to solvent free, UV ink also has such advantages as not easy to paste, clear dot, bright ink color, excellent chemical resistance, consumption and so on.

Water-based UV ink: Water-based UV ink is a new research direction in the field of UV ink. The viscosity of the prepolymer in ordinary UV ink is generally very large, and it needs to be diluted with active diluent. The diluent acrylate compounds used have different degrees of skin irritation and toxicity, so in the development of low viscosity prepolymers and low toxic activity diluents at the same time, another development direction is to study water-based UV ink, that is, water and ethanol as diluents. Water-based UV ink has been successfully developed and applied in some printing.

Alcohol-soluble ink: The alcohol-soluble ink that mainly plays a role in flexographic printing is also a kind of ink with little public harm, which is mainly used in food, medicine, beverages, tobacco and alcohol and daily use packaging and printing in contact with the human body.

Standard ink: Printing inks are generally the same type of standard ink produced by each ink factory. In addition to color, the main difference in ink tone is the different luster of the ink skin film, there are shiny gloss type and no light type, between the two is semi-bright ink.

Spot ink: Spot ink is based on the color standard of the original design, using the existing color ink and auxiliary agent to prepare a special color ink. The original color continuous tone images are overprinted and reproduced using yellow, fine, blue and black four-color dot plates, and do not require special color ink. However, in packaging products, advertisements, book covers and other color prints, most of the colors used are flat painted with spot colors.