There are many types of printing presses, which can be classified according to the following five aspects:
1. According to the layout type, it is divided into: letterpress printing machines, lithographic printing machines, gravure printing machines, and stencil printing machines;
2. According to the paper size and specification, it is divided into: lithographic or sheet-fed printing presses, web printing presses;
3. According to the printing color number, it is divided into: monochrome printer, two-color printer, multi-color printer;
4. According to the printing format, it is divided into "eight-sheet printer, four-sheet printer, folio printer, full-sheet printer, super-full-sheet printer, etc .;
V. Although there are many classification methods for printing presses, the core part of printing presses is the embossing mechanism of the printing device. Therefore, according to the method of applying pressure, the printing presses are generally classified into flat flat, round flat, and round. Round type, oblique flat type.
The flat and flat type flat and flat printing machine is characterized in that the plate loading mechanism and the printing mechanism are both flat.
During printing, the embossing lithography swings back and forth around the main shaft to complete paper feeding and embossing. Because the ink of the graphic part of the printing plate and the embossing lithography are all in contact at the same time, the embossing time is longer and the pressure on the substrate is greater, so the ink color of the printed matter is thick and the lines and strokes are full.
Flatbed flat type printing machine, small size, slow printing speed, low production efficiency, suitable for printing small prints, such as: greeting cards, invitations, book covers, envelopes, labels, etc. This type of printing machine includes movable type printing machine, copper-zinc plate proofing machine and disc machine.
The round flattening type is also called a flatbed printing machine. Its structural characteristics are that the plate loading mechanism is flat, and the embossing mechanism is a round cylinder, commonly known as an imprinting cylinder, as shown in the figure.
When printing, the printing plate is moved back and forth relative to the platen with the platen loading platform. The platen roller is generally in a fixed position, and the plate is rotated while the plate is being pressed. The pressure ratio of the platen to the plate is The flatbed and flatbed printing machine has been greatly improved, but due to the reciprocating movement of the platen, the printing speed is limited and the production efficiency is not high. Mainly print the text of books and periodicals. This type of printing machine includes: a rotary letterpress printing machine, a double rotary letterpress printing machine, a rotary rotary letterpress printing machine, a planographic proofing machine, and the like.
Rotary presses are also called rotary presses, and their structural characteristics are that the printing press and printing mechanism of the plate loading machine are cylindrical cylinders, and the cylindrical plate loading mechanism is commonly known as the plate cylinder, such as As shown.
During printing, the impression cylinder carries the substrate, and the impression is rotated while rotating in the opposite direction with respect to the plate cylinder. Because the contact time between the impression cylinder and the plate cylinder is relatively short, the pressure applied to the substrate is less than that of a round flattening press.
The circular press is a round press, which makes use of the non-stop contact between the impression cylinder and the plate cylinder to carry out embossing. 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 unit-type printing machine, double-sided, multi-color printing can also be performed, and the production efficiency is very high. At present, such printing presses are most commonly used, such as lithographic printing presses, gravure printing presses, flexographic printing presses, and high-speed web printing presses for printing books and newspapers.
According to the layout type, it is divided into: letterpress printing machines, lithographic printing machines, gravure printing machines, and stencil printing machines.
Letterpress printing machine The letterpress printing machine is the oldest printing machine, the graphic part of the printing plate surface is convex, and the blank part is concave. When the machine is working, the rubber roller coated with ink rolls over the surface of the printing plate, and the raised graphic portion is covered with a uniform ink layer, while the recessed blank digital printing machine is not stained with digital printing machine. The pressure mechanism transfers the ink to the surface of the printed matter, so as to obtain a clear print and reproduce the required print.
There are three types of letterpress printing presses: flattened, rounded and rounded. Flatbed flat letterpress is also called flatbed printing press. The plate platform and the embossing mechanism of the device are flat. When working, the printing plate is in full contact with the embossing plate. The total pressure on the machine at one time is relatively large and the relative embossing time is long. This type of printing machine requires that the printing plate and the platen are flat, and the printing format is not large. The circular platen relief printing machine is also called a flatbed printing machine. The platen for the printing plate is flat, and the printing mechanism is a round cylinder. . When the machine is working, the platen moves back and forth, the printing speed is limited to a certain extent, so the output is not high; the circular platen letterpress printing machine is also called a rotary printing machine, and the platen plate and the embossing mechanism of the plate are round cylinders. When the machine is working, the impression cylinder moves with the printed matter and comes into contact with the plate cylinder. The impression cylinder and plate cylinder rotate continuously and rapidly, so the productivity is high.
The lithographic printing plate and the graphic portion of the lithographic printing plate surface are almost on the same plane. It uses the principle of water printing machinery printing machinery and oil repellence to make the graphics and texts resistant to water and oil, the blank parts are resistant to oil and hydrophilic without staining the ink, and the ink of the inking part is transferred to the surface of the printed matter under pressure to complete the The printing process.
After adopting the indirect printing method, lithographic printing presses have developed rapidly and there are many varieties, such as mini offset presses for office use, large, multi-color, high-speed offset printing presses for books, magazines, and magazines. Single-sided or double-sided lithographic printing presses. Among them, monochrome offset presses and web offset presses are representative. Lithographic printing presses have widely adopted electronic computer control devices and are becoming increasingly technologically advanced. Plate-making equipment has also been developed to use electronic color separation machines, and pre-coated photosensitive plates are widely used.
The main features of the gravure printing machine are that the graphic part on the printing machine printing plate is concave, and the blank part is convex, which is exactly the opposite of the layout structure of the letterpress printing machine. When the machine prints a single color, the printing plate is dipped in the ink tank and rolled, and the entire printing plate surface is coated with an ink layer. Then, the ink layer on the surface of the printing plate that belongs to the blank part is scraped off, the raised part forms a blank, and the recessed part is filled with ink, and the deeper the recessed part, the thicker the ink layer is. The machine transfers the ink of the recessed portion to the printed matter by the pressure, thereby obtaining the printed matter.
When printing multiple colors, the overprinting method or indirect partial ink coating method is used, so that the inks of various colors are distributed on the relevant parts of the surface of the printing plate as required. The basic printing principle of printing multiple colors is the same as that of monochrome printing. There are mainly two types of printing plates used by the gravure printing machine, one is a photogravure, that is, a photocopying plate; the other is a engraving plate. The engraving version includes hand engraving, mechanical engraving and electronic engraving.
Screen printing machine Screen printing machine is a representative printing equipment in hole printing machinery printing mechanical plate printing machine. Its printing plate is a crisscross screen with clear warp and weft woven from silk and other materials. Has produced a variety of screen printing machines such as flat, curved, forming, printing and dyeing, printed circuits and new types of rotary. Among them, the new rotary screen printing machine is relatively high in speed and productivity. It is characterized in that the screen is installed on the cylinder, and the ink is poured into the cylinder. When the machine is working, the cylinder rotates, and the rubber squeegee quickly prints the pattern on the printed matter.
In addition to silk, the silk screen can be made of nylon, copper, steel or stainless steel. The principle of stencil printing applied by screen printing machines originated from ancient stencil printing. Stencil printing comes in a variety of forms, including stencil printing, hollow printing, and screen printing.
Screen printing was originally performed manually. At that time there was only one plate rack, one screen plate, and one stencil. Only in the 1950s did screen printing become mechanized and automated. Drum screen printers have a large amount of ink when printing, which is suitable for printing thick prints. It can be printed on a variety of paper, glass, wood, metal, ceramic, plastic or cloth. A variety of inks are available, including conductive Metallic ink.