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2021.10.13
According to the relative position of graphic and nongraphic areas on the printing plate, the common printing methods can be divided into four categories: relief printing, gravure printing, lithography, and hole printing. Next, we will introduce these 4 types of printing to you, relief printing, gravure printing, lithography, and hole printing.
What is relief printing?
Relief printing is a kind of printing using a relief plate (a printing plate with a raised image and text part, referred to as relief printing, which is one of the main printing processes. The graphic part of the printing plate is convex, which is significantly higher than the blank part. The printing principle is similar to the seal. The early woodblock printing, movable type printing, and later type printing belong to relief printing. Scope of application: trademark, packaging and decoration printing, newspaper printing, etc.
Characteristics of relief printing
The paperback of the printed matter has a slight impression bulge, the edge of the line or dot is neat, and the printing ink appears light in the central part, and the raised image edge is under heavy pressure, so there is a slight impression bulge.
Characteristics of letterpress printing
The ink color is thick (the thickness of the ink layer is about 7 μ m) It can be printed on rough substrates. Tone reproducibility is average.
Common relief printing methods
Movable type printing (including clay movable type and lead movable type), flexo. Only flexo is still widely used.
Common letterpress
Common relief printing presses mainly include parallel multicolor relief printing press and cascade multicolor relief printing press.
What is gravure printing?
Gravure printing, referred to as gravure printing, is one of the four printing methods. It is a plate-making technology in which the image is carved concave from the surface. The concave graphics and texts are carved on the metal plate by hand. During printing, the ink is applied to clean the ink on the plate, and only the ink left in the concave part is transferred to the paper.
Application: gravure printing is mainly used for fine publications such as magazines and product catalogs, packaging printing and printing of securities such as banknotes and stamps, as well as special fields such as decorative materials.
Gravure printing carries ink in pits carved according to the original text. The thickness of lines and the thickness of the ink can be controlled arbitrarily during engraving, which is not easy to be imitated and forged, especially the depth of ink pits. The possibility of realistic engraving according to the printed text is very small. Gravure printing uses a large amount of ink, with convex graphics and texts, rich levels, clear lines, and high quality.
It is printed by round pressing and direct printing. The printing plate is directly made on the printing plate cylinder, and the ink is fed by ink dipping or inkjet. There is no ink leveling mechanism. Due to the thick ink layer, the use of volatile fast-drying ink must have a drying device.
The types of gravure printing are divided into two categories according to the plate-making methods: engraving gravure and etching gravure.
Engraving intaglio is to directly carve pits corresponding to the original pictures and texts on the surface of the printing plate cylinder with a cutter. According to the control method of the cutter, it can be divided into manual engraving intaglio, mechanical engraving intaglio, and electronic engraving intaglio.
Etching gravure is made by etching ink pits on the surface of the printing plate cylinder by chemical etching according to the original text. According to the different methods of image text conversion of the original, the etching gravure can be divided into etching gravure, photographic gravure, and dot gravure.
The model is divided into sheetfed and web gravure printing machines according to the different papers used. According to the number of colors printed at one time of the unit, it is divided into monochrome, four-color, five-color, and six-color, as well as single-sided printing and double-sided printing.
Lithography is a printing method originally based on the immiscibility of oil and water. Lithography, also known as offset printing, is the most widely used printing method in the printing industry; The principle is to press the ink on the printed paper through the rubber glue through the roller, to make different prints. Suitable for posters, personal data, brochures, newspapers, packaging, books, magazines, calendars, and other black printed materials.
Lithography plate making is simple and low cost; The color registration and plate loading are accurate, and the printing plate is easy to copy; The printed matter is soft and soft, and can be printed in large quantities.
Lithographic printing method
The lithographic round press is that the printing plate is laid flat, and the pressure part is a roller press cylinder. This printing method is very similar to the lithographic round press machine in relief printing. Round plate round pressing is to wrap the printing plate on the drum, which is called plate cylinder. The other drum on the machine is wrapped with rubber, which is called a rubber cylinder. The pressure part is the same drum-type pressing cylinder.
Lithographic printing includes lithographic printing, offset printing, collotype printing, etc., but now basically only offset printing is left, and other types are rarely used.
The lithographic press is different from other printing methods in that it is equipped with a fountain device. Except for lithography machine, lithography machine, and proofing machine, they are all round presses
Hole printing is also called silk screen printing, that is, a printing method using the screen as a plate. The graphic part of the printing plate can be leaked to the substrate through the printing ink to form the printing method of the image.
Hole printing has a wide range. It can be used to make printmaking works, and can also be used for packaging and printing of daily necessities and industrial supplies.
Compared with embossing, lithography, and other printing methods, screen printing has the unique advantages of fast plate making, simple printing methods, less equipment investment, low cost, and wide printing range.
Hole plate printing is done through printing, so the ink feeding device is on the plate, and the paper is placed under the plate. The printing method is that the plate is normal grain through printing, and the plate is still normal grain after printing. Due to the different printing purposes, the layout can also be made into a curved plate with the surface of the printed matter. Any layout beyond the limits of the three printing formats can generally achieve the purpose of hole printing.
The printing plates used in hole printing are generally divided into two categories: transcription plate and screen plate. The transcription plate is made of special wax paper, which is carved with an iron pen, typed with a typewriter, or scanned with an electric spark. It is printed by transcription plate, commonly known as “mimeograph”. It is mainly used to copy office documents.
Screen printing plate, the layout is reticular, which is composed of the film layer, screen and screen frame with empty pictures and texts. In recent years, screen printing has developed rapidly, which is used in labels, advertising, printing and dyeing, and map reproduction. Here mainly describes the production of the screen printing plates.
The hole plate printing machine belongs to the representative printing equipment in the hole plate printing machine. In addition to real silk, nylon wire, copper wire, a steel wire or stainless steel wire can also be used to make the screen. It can be divided into plane screen printing machines, curved screen printing machines, rotary screen printing machines, etc.