Offset ink classification and selection

With the advancement of the printing industry and the continuous improvement and improvement of printing technology and printing equipment, offset printing is characterized by its unique advantages, such as rapid and convenient plate making, low cost, high printing quality, wide range of paper use, and large print volume shrinkage. The favor of printing manufacturers at home and abroad has led to rapid and extensive development, which has led to a dominant position in the international printing industry. Offset printing inks have also experienced rapid development.

Ink is the most important printing material for information reproduction and should have good printability during the printing process. Offset inks are mainly composed of colored pigments (dye, etc.), binders, fillers, and additives, and are mixed and stirred according to the requirements of the printing according to the requirements of the printing, and are manufactured through the rolling and pressing process.

Pigments are solid powdery materials that are insoluble in water, and are not soluble in oil or binders, and have a certain color, and include inorganic pigments and organic pigments. It is not only the main solid component in the ink, but also the part of the color body that is printed on the object. To a large extent determines the ink's color, thick, light and other properties. The black pigments used in printing inks are mostly inorganic substances (such as carbon black), and the color inks are mostly organic pigments.

Offset printing inks can be divided into sheet-fed offset printing inks and rotary offset printing inks according to the printing machinery. According to different drying methods, they can be divided into penetrating offset printing inks, thermosetting offset printing inks, and photocuring (UV/EB) offset printing inks. Iron offset printing ink. Different types of inks have different printability and uses.

Selection of Offset Printing Inks for Different Printing Machinery and Different Substrates

1. Web Offset Printing Ink

The ink used in the web offset press is usually called the offset rotary ink. The ink is basically divided into the following two types: a. Osmosis drying type: Due to the high printing speed of newsprint paper and offset paper web offset printing press, the drying speed of ink is fast, so the commonly used inks are mostly osmotic drying type. b. Thermosetting inks: In modern commercial web offset presses, a drying device is added to the second half of the printing device. In order to adapt to this production condition, a thermosetting ink is used. This ink is heated in a drying device and the ink is The volatilization of the solvent allows the ink film to dry quickly, and the dry oil (such as linseed oil) in the thermosetting ink contains less. The amount of petroleum agent is more, and other components are slightly the same as those of the sheet-fed offset printing machine. The paper used for the thermosetting ink is better than the paper used for the infiltration-drying type ink.

2. Sheetfed Offset Printing Ink

1 offset bright ink

Offset Bright Ink is a high boiling paraffinic oil made from synthetic resin, dry vegetable oil. Colloidal ink composed of high-quality pigments and additives. For monochrome, two-color or multi-color offset printing machine in the printing paper, pictures and other sophisticated fine prints. The gloss of the ink is mainly caused by the conjunctiva after drying of the linking material. The gloss of the ink and the leveling of the ink film are good. The surface of the substrate to be printed should be able to form a flat surface, and be directional reflection of the incident light, that is, it has a mirror effect. Ask the binder to stay at the surface of the substrate as much as possible.

2 offset resin ink

Offset resin inks are made of synthetic resin, dry vegetable oil, mineral oil, high-quality pigments and fillers, and are formulated and ground. Offset resin inks are characterized by less vegetable oil content and a high proportion of solvents, usually high-boiling alkane, which act as a viscosity-reducing agent in the ink. When the ink is transferred to the paper, this part of the solvent quickly penetrates into the paper fibers under the action of the capillary, which speeds up the drying of the ink and reduces the breakdown of the printed product.

3UV offset printing ink

Printing with UV inks in offset printing is commonly referred to as UV offset printing. UV offset printing ink is a type of ink that uses ultraviolet (UV) radiation energy to cure liquid chemicals by rapid cross-linking to form an ink film. It requires a UV curing unit in the press. UV offset ink as a kind of offset ink, it must first be able to print by offset printing, so UV offset ink should also have some characteristics of ordinary offset ink to meet printability requirements.

4 offset synthetic paper ink

In the absence of a UV offset printer, the use of ordinary four-color printing machine printing cardboard, synthetic paper and some inks on the surface of the substrate is not easy to dry the special paper, you need to use offset synthetic paper ink, this ink is suitable for printing Non-absorbent printing substrates such as various synthetic papers (gold cardboard, silver cardboard, aluminum foil, and specialty paper) have fast drying properties and good adhesion properties. Due to the very fast drying speed of the ink, when the printing process is stopped, the ink on the rubber roller should be cleaned in time to prevent the ink crust from drying.

With the development of science and technology, people are increasingly demanding environmental protection, so green ink came into being. Eco-friendly ink is also called green ink. In offset printing, there are mainly soy ink and ultraviolet-curing ink.

Ultraviolet curing ink is also called UV ink. The main characteristics of UV ink are: no solvent evaporation, no pollution, conform to environmental protection requirements, widely used in food packaging and printing, good printability, suitable for printing paper, cardboard, plastic products, metals, textiles and other printing materials, curing time is short Less energy consumption and good quality of printed products.