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about offset printing
Author: Elena Ruan, sales manager of shanghai custom packaging Email: email@example.com
offset printing is an indirect method of lithographic printing. The offset printing method has far verbeitet in today's everyday life and the classical typography displaced very quickly. Currently an estimated 60% of all printed material produced by the offset printing process. Offset printing is based basically on the stone pressure (direct inking of the ink ribbon to print object and thus direct printing process) and has evolved into an indirect printing method.
Offset printing - printing technology
As a planographic printing method is based also the offset printing on the different physical reaction of water and fat. This surface structure uses one to spend color and remaining free space on the same level. Only on the fat (lipophilic) surface adheres the fat- or oil-based paint. The hydrous (hydrophilic) surfaces repel the ink. This leaves only color to be printed surfaces stick.
The pressure cylinder with the inking (print form) is printed directly on the printing object, but switched a blanket cylinder (blanket) in between. This has its historical cause that could not reasonably be printed otherwise hard print objects (such as zinc on sheet). Also, the color adherent surfaces thus consume less quickly. The print object (usually paper) is thus pressed by the impression cylinder to the blanket cylinder and conveyed. The power transmitted to the blanket cylinder color sticks to the paper. Overall, therefore, the print object is printed only indirectly via the blanket cylinder. Hence the term offset forwards settle for or offset from what was eponymous for offset printing.
From print object (substrate) ago, all flat materials can be printed. This is known as a thin sheet of material. Because of the blanket as a transfer agent also papers with rough surface can be safely printed so about.
Since the print object is wetted printing process, size shifts are possible, provided that the material to be printed reacts-swelling water.
Offset printing - the colors
The printing unit (printing) is a color possible. It is also described as an inking unit. one starts from the most commonly used color space CMYK, you can already cover with machine with four color works very many colors. Even if only cyan, magenta, yellow and black are available, almost any mixing ratio may be generated by a fine grid. This is based on an optical blurring of the human eye, which can recognize only from close the individual color points of the four colors. These are printed as small dots sent next to or above each other, so that the human eye perceives a semitone (mixed color) is created. This can be seen from the photos in detail in almost every major newspaper.
For colors outside the color model and special colors such as gold, silver, there are several other color palettes such as Pantone.
Does the printing machine for more than four inking units can be a previously precisely commingled full color as so-called spot color to the four basic colors and their gridded "mixture" use. This makes sense when it comes in the context of a corporate look (corporate design) on a certain hue. So this must not be imitated by a scan, but can be applied as ready-mixed color.
To achieve the standard color scales in the print result, there are different quality criteria for the colors (pigments). In addition, care, expertise and saving drive of the printing machine operator play a not insignificant role.
Sheetfed offset and web offset printing
Used as substrate cardboard or paper, one can distinguish between sheetfed offset and web offset printing. If the paper individually fed in sheet form, one speaks of the sheetfed offset printing. the paper comes out of (sometimes very large, extremely heavy) paper rolls, one speaks of the web offset printing. In sheetfed offset printing, a distinction according to the size (paper size) of the fed sheets.
Sheetfed offset printing makes regularly from 1,000 to 50,000 pieces sense. For long runs (economically from about 50,000 copies) therefore one uses paper rolls, so that most of the web offset printing is used in newspaper printing, catalog printing or label printing. still is for very high volume of the rotary printing more economic and possibly faster alternative. The relevant print run shifts but more and more in favor of web offset printing. With approximately 700,000 pieces per edition both printing processes competing mostly at the same level.
The newspaper format are usually also due to printing (size: broadsheet, small: Tabloid).
Waterless offset printing
Also, the waterless offset printing method is a method of lithographic printing with indirect inking. And also in this method, the printing plate has to be printed points which are wetted with ink and those which do not receive ink.
The difference lies in the surface treatment of the non-printing positions. During this the wet process - as described above - are coated with water, comes in the dry method, a thin layer of silicone used. The silicone eliminates the use of water completely, and thus leads to a series of advantages over the conventional method. For example, also eliminates the use of the chemical components such as isopropanol. In addition, the balance between water and chemical components no longer matters what cancels their binding to machine time and personnel expenses and so the spoilage reduces by 30 to 60 percent.
Advantages of waterless offset printing
high process stability
low start-up waste
less ink consumption
no paper sources
fewer registration problems
better printing of wide web
no ink zone presetting and fan-out correction
thicker layers of paint possible
no corrosion of metal colors
better fine detail
lower dot gain
Suitability for particularly fine screens, FM screening, periodic scanning and fine reverse type in solid areas
simpler, quieter and smaller machines
lower maintenance and cleaning
no corrosion of steel components
no treatment, control and disposal of the dampening solution
reduced dust exposure
Gumming of plates not necessary
Plates are expensive and susceptible to scratching
Plates are hard to correct
Printing inks are more expensive, not all colors available, some special binder needed in the colors
sometimes highly speedy colors are needed
sometimes the addition of silicone oil is needed
Printing process is temperature sensitive
the engine cooling necessary
Ausgerupfte paper fibers are not removed, thereby more slugs
Offset printing - the characteristics
Since the printing plate having no increases (high pressure), no coins or shades make their way on the printing object. The round sharpness of characters is high. Only the grid can be seen on closer inspection. Incorrect positioning of the dots and / or incorrect angulation of the halftone dots, a pattern of staggered small circles yields (Moiré effect). This error is easily recognizable.
In offset printing process prints produced on the basis of the film are water and weather resistant and resistant to UV rays.
Shanghai custom packaging co., ltd offer such high quality printing works, if you are interested in, please feel free to contact us.
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