1, the use of elastic body embossing liner (liner material)

The pressure applied between the printing press and the printing plate is achieved by the embossing mechanism (metal roller or imprint lithography). The surface of the imprinting mechanism and printing plate of the printing press is mostly made of metal materials. The metal material can be considered as a rigid body that does not substantially deform under pressure. It is unavoidable that two kinds of metal rigid bodies are in contact with each other, and wear due to collisions is inevitable because the hardness of the printing plate is generally lower than the hardness of the roller or the imprinting lithography plate. If the imprinting mechanism is in contact with the surface of the printing plate, the printing plate is more easily damaged. Therefore, the surface of the imprinting mechanism must be covered with a layer of cushioning material with certain elasticity, and the elastic deformation can be used to reduce the wear caused by the contact of the two rigid bodies, thereby protecting the printing plate and improving the printing plate's resistance to printing force. In addition, the elastic deformation of the underlay under pressure can also be used to compensate for the unclear imprinting defects caused by the unevenness of the printing plate or the rough surface of the substrate, so that the substrate can obtain a clear and perfect print.

The liners often used include paper, woolen cloth, rubber, plastics, cloth, and other materials. The cushioning material is different from the flexibility of the printing (related to the size of the drum diameter and the speed of the machine), and is composed of different materials. According to the combination and nature of the cushion material, it is generally divided into three types: rigid liner, neutral liner and soft liner. These three liners have different elastic values ​​of extrusion deformation and can be used for printing.

(1) Hard liner:

Hard liners, also known as hard liners, are formed from paper under a rubber plate. This lining provides less pressure and less elasticity for proper transfer of graphic inks. In general, the hard-liner has little auxiliary elasticity for the backing and only relies on the elasticity of the eraser itself. The general control range of the rigid liner is: the liner thickness of the blanket plus liner is less than 2mm, and the printing pressure is generally controlled at 0.04-0.08mm, and the maximum limit is not more than 0, 10mm. Hard lining features a solid, full print with a small print pressure. Dot gains and distortions are smaller.

(2) Neutral liner:

Neutral liners, also known as neutral liners, are between hard and soft. The liners are blankets plus tape and paper. The lining thickness is about 3.00-3.50mm, and the printing pressure is generally controlled between 0.15-0.20mm. Neutral liners have moderate hardness, printed dots are clear, and point-shaped smooth finishes are low. The flexibility of the lining material selection is relatively large, generally can be divided into two types: neutral soft pad or neutral hard pad, neutral soft lining, most of them are used without contact with the pillow printing machine.

(3) Soft liner:

The soft liner is also called the soft liner, and the soft liner is provided with a thick liner, a large pressure, and a large elasticity to obtain the transfer of printing ink. The liner material is a felted liner. The general control range of the soft liner is that the lining thickness is about 4mm, and the printing pressure is generally controlled between 0.20-0.25mm, and some reach 0.30mm.

This lining, the surface is flexible, large deformation, imprint contact arc width, poor wear and tear of the printing plate, not easy to appear "bar", but the network spreads easy to spread, point is not correct, the printing quality is poor, so soft lining It is generally suitable for worn old institutions.

The following table shows the suitability of the three types of pads: different papers, different printing plates, and different printing methods. The requirements for cushioning objects are quite different. The elasticity data of various materials should be measured first, and then these materials should be assembled into a liner, and then printed on a printing press to observe and compare the print quality under different printing numbers to determine the nature of these liner materials.

Reprinted from: Feilang Carton Design