The difference between a screen printing machine and an offset printing machine
1. Screen printing belongs to stencil printing, and it is called the four major printing methods together with flat printing, gravure printing, and embossing printing. The principle is that the printing plate passes a certain pressure during printing to transfer the ink through the holes of the stencil to the substrate to form images and characters.
(1) Strong adaptability: It can be printed on flat, curved, spherical, concave-convex substrates.
(2) Ink layer thickness: strong three-dimensional effect, rich texture, the ink layer thickness can generally reach about 30μm, while offset printing is 5-10μm.
(3) Strong light fastness and bright color.
2. Dry offset printing belongs to letterpress printing: first transfer the ink on the graphic on the printing plate to the rubber cloth roller, and then transfer the ink to the printed matter through the rubber cloth roller. Features: It is suitable for cylindrical, conical, and rectangular containers, but it is difficult to print non-cylindrical containers. Multi-color printing on containers by offset printing is more economical than screen printing, so it is widely used.
Disadvantages: the printing gloss is poor, the edges of the graphics and texts are not clear, the dots of the printing plate are too small, the dots will penetrate into the rubber and the dots of the printed matter will expand, and the printing effect is poor.
The difference between Screen Printing Machines and offset printing
1. Screen printing is an ancient printing method. There are many aliases for screen printing, such as silk lacquer printing, silk Screen Printing Machine, serigraphy printing, gauze printing, screen printing, and so on. Silk screen printing initially used silk as the net material, so it was called Silk Screen Printing (screen printing) in the early stage of the world. Since the mesh material has been replaced by a large number of synthetic screens, Screen Printing (screen printing) has been used.
The basic principle of screen printing is: part of the holes of the screen printing plate can pass through the ink and print on the substrate; the rest of the mesh on the printing plate is blocked and cannot pass through the ink, forming a blank on the substrate.
The traditional plate-making method is manual, and the photochemical plate-making method is more commonly used in modern times. In this plate-making method, the screen is used as a support body, and the screen is tightened on the screen frame, and then photosensitive glue is coated on the screen to form a photosensitive plate film, and then the positive negative plate is tightly bonded to the plating film to expose the plate. exposure. Developing, the part of the printing plate that does not need to be over-inked is exposed to light to form a solidified plate film, which seals the mesh and prevents ink from penetrating during printing. Black marks form on the substrate.
Stencil printing, letterpress printing, gravure printing, and lithography are called the four modern printing techniques. The screen printing machine is one of the main printing methods in stencil printing. Like screen printing, it belongs to stencil printing, as well as Yushu printing, typing wax printing, floor printing, and inkjet printing.
flat. concave. The three printing methods are all printing methods in which the printing plate transfers the ink to the substrate, while screen printing is a printing method in which the ink leaks onto the substrate through the mesh of the printing plate image. Therefore, there are more and more types of inks that can be used in Screen printing machines, and the substrates are not limited to paper, metals, and metals. plastic. Wood, etc. can be screen printed.
2. One of the most important reasons why offset printing technology can develop at such a fast speed lies in the printing advantages of offset printing.
Traditional offset printing technology uses the principle that water and oil do not mix, and uses offset printing technology to print through the intermediate transfer rubber cylinder. In the past two or three decades, with the development of new technologies such as polymer materials and lasers, offset printing materials (including printing plates, inks, fountain solutions, blankets, etc.) and corresponding plate-making technologies have also made great progress. It laid the foundation for offset printing to meet the high printing quality, high printing speed, and low printing cost required by the printing market.
At the same time, because offset printing adopts the indirect printing method (intermediate transfer rubber cylinder), the printing pressure can be smaller and the contact with the printing material is better, which ensures the good transfer of graphics and text, and improves the application range of printing materials and the durability of printing plates. The printing rate also provides a guarantee for a more reasonable mechanical structure design.
Not only pre-press technology and offset printing materials have made great progress, but offset printing equipment has also continued to improve with the rapid growth of the offset printing market. The printer invested a lot of money and energy, first of all, a lot of improvements were made to the structure of the offset printing machine, and even a new design was made. Make it more suitable for high-speed, high-quality printing. Such as the development of a high-speed offset printing paper feeder, the improvement and development of new mechanisms such as pneumatic paper feeding board, high-speed paper feeding teeth, and new side pull gauges; new ink feeding and water feeding systems have been developed. At the same time, it adopts various cylinder arrangements, cylinder diameters, and paper transfer and turning mechanisms to meet the different requirements of various printed matter printing, and is suitable for printing more different printing materials.
In terms of printing automation, offset printing equipment is one of the fastest-growing printing equipment. From pre-press laser phototypesetting, electronic color separation, and full-page imposition to digital proofing (CtProof), digital filmmaking (CtFilm), digital plate making (CtPlate) technology; The printing plate scanning device, quality control device, and fully digital "one-button productivity" control system make offset printing equipment a leader in the market in terms of improving production efficiency, reducing labor intensity, reducing printing preparation time, and reducing consumption.
In addition to the rapid development of the traditional offset printing system, the offset printing family has also added many new members. For example, with the research, development, and gradual marketization of waterless offset printing plates, the development of waterless offset printing systems has been greatly promoted, and a series of problems caused by the use of dampening solutions to printing quality has been improved, such as water-ink balance problems, ink Emulsification, water deformation of paper and environmental pollution.
Wenzhou Changs Machinery Co.Ltd. is one the companies specializing in the production of printing machinery, packaging machinery, plastic machinery, and paper processing machinery, and has had an import and export license since 2004. Considering our all-around service convenience, we set up a serviced office and showroom in DRAGON-MART, Dubai in 2006 to provide technical services to customers from the Middle East and Africa, and set up technical support offices in Mexico, Egypt, and Singapore, Our service satisfies all customers.