Element Analysis of Printing - Printing Machinery

Fifth, printing machinery

Printing machinery is the general term for machines and equipment used to produce printed products. Its function is to transfer the printing ink to the surface of the substrate.
Printers generally consist of paper feeders, ink inkers, printers, and paper collectors. The lithographic printing press also has a water delivery device.
There are many types of presses that can be classified in the following five aspects:
According to the layout type is divided into: letterpress printing presses, offset printing presses, gravure printing presses, aperture printing presses;
According to the paper size specifications are divided into: lithographic paper or sheetfed printing presses, web printing presses;
According to the number of printing color is divided into: monochrome printing presses, two-color printing presses, multi-color printing presses;
According to the printing format is divided into "eight open printing presses, four open printing presses, off printing presses, full sheet printing presses, super full sheet printing presses.

Although there are many methods for classifying printing presses, the core part of the printing press is the embossing mechanism of the printing apparatus. Therefore, depending on the manner in which pressure is applied, the printing press is generally classified into a flat pressing type, a round pressing type, and a round pressing type. There are three types.

(A) Flat Presses

The structural features of flat presses are that the platen and embossing mechanisms are flat, as shown in Figure 2-4.

During printing, the imprint lithographic plate swings back and forth around the spindle to complete the paper feeding and imprinting. Since the ink and the imprint lithography of the printing plate graphic portion are all in contact at the same time, the imprinting time is longer and the pressure exerted on the substrate is greater, so the ink color of the printed matter is heavy and the lines and strokes are full.

Figure 2-4 Flat Press Flat Press Structure

Flat-press type printing machine, small volume, slow printing speed, low production efficiency, suitable for printing materials with small format, such as: greeting cards, invitations, books and magazine covers, envelopes, labels and so on. This type of printing press has movable type machine, copper and zinc proofer and disc machine.

(B) Round Flat Press

Also known as a platform printer, its structural features are that the plate-loading mechanism is flat, and the embossing mechanism is a circular cylinder, commonly known as an impression cylinder, as shown in Figure 2-5.

Figure 2-5 Schematic diagram of a round press

During printing, the plate moves with the platen relative to the platen, and the platen is generally in a fixed position. The substrate is imprinted with the substrate while being rotated, and the pressure applied by the platen to the substrate is greater than that of the platen. Flat presses have been greatly improved, but due to the reciprocating movement of the table, the printing speed is limited and the production efficiency is not high. The main text of the printed book. Such printers include: a rotary letterpress printer, a two-rotation letterpress printer, a rotary rotary letterpress printer, and a lithographic proofer.

(III) Round press circular printing machine

Also known as a rotary printing press, its structural features are that the plate loading mechanism and the embossing mechanism are all cylinder-shaped cylinders, cylindrical loading mechanisms, commonly known as plate cylinders, as shown in Figure 2-6.

Figure 2-6 Schematic diagram of circular press

During printing, the impression cylinder bears the substrate and is imprinted against the plate cylinder while rotating in the opposite direction. Due to the shorter contact time between the impression cylinder and the plate cylinder, the pressure exerted on the substrate is less than that of the round-enamelling press.

The round press type circular printing press makes use of the contact between the impression cylinder and the printing plate cylinder and imprinting. The movement is stable, the structure is simple, and the printing speed is fast. If the printing devices are combined together and designed as a satellite-type or group-type printing machine, double-sided and multi-color printing can also be performed, resulting in high production efficiency. This type of printing press, which is currently used most, has lithographic printing presses, gravure printing presses, flexographic printing presses, and high-speed web-fed printing presses for printed books and newspapers.





Author: FENG Rui dry

Source: Introduction to Printing