Screen printing plate production
Screen printing has its own characteristics compared with other printing.
(1) Screen printing color, thick ink film, unlike letterpress printing, lithography ink film is very good, can not be used to express the subtle changes in tone;
(2) When using the original drawing lines, it is not required to have too fine lines, screen printing plate system for too fine lines, production is not easy, at the same time, the later printing effect is not very good;
(3) Lithography and letterpress are more expressive than screen printing. In screen printing, the matching relationship between the mesh number and the mesh number requires a lot of time to determine. Therefore, high line digital screen materials are generally not selected for production.
In screen printing plate production this, most of the current use is photosensitive plate.Its platemaking effect is good, high quality, cost-effective, so modern screen printing in the most important platemaking method or this.
The photosensitive plate making method USES the photochemical change principle of the photosensitive adhesive, that is, the photosensitive adhesive under the light part will harden, produce cross-linking, and closely combined with the screen to form the template L3L.In the later stage of water or other developer to wash the photosensitive part, will form holes, screen printing plate.
(1) Light-sensitive materials
The imaging principle of plate film photosensitive material is exposure curing, developing and developing the image.Light-sensitive materials are required to have the following characteristics:
(1) Good plate-making performance, such as easy to smear, has a wider photosensitive spectrum, the wavelength range should be between 340 — 440nm;
(2) good stability, in order to facilitate storage, in order to reduce waste;(3) low price, non-toxic, yuan of public hazards;
Version of the film to adapt to different solvents and dyes performance requirements, has a better solvent resistance;(5) good adhesion with the screen, high printing resistance, easy to peel, conducive to screen recycling;
(2) Printing equipment
Screen plate – making process, the traditional manual engraving method has been replaced by photosensitive plate – making method.The use of photosensitive screen process, a very important process for print.
In print, the choice of light source is particularly important, not only to consider the economy of the light source, but also to consider the sensitivity of photosensitive materials to light source and absorption factors.As a result of high chromogenic fluorescent lamp source is sufficient, the price is cheap, it is the illuminant with the most extensive use so.
In the production process, plate printer is one of the very high frequency of use of equipment, it is composed of bottom frame, glass basking frame, lamps, vacuum pump and other components 41.Factory scale is larger, or need to print the death of more, you can choose to print the machine.If small-scale production or just start, you can make a simple plate printer or plate box.
In order to improve the quality of the template, in the process of printing, only the light source generated by the light irradiation on the layout, can not have other light irradiation on the layout.The strong light of outdoor light, bask in edition illuminant is irradiate on indoor wall and other article, the light that is reflected on if glass is the illuminant influence that cannot ignore.Light to direct in the layout is the most important, oblique ray irradiation insolation version is not good.Had better use protective cover to prevent oblique ray, use black curtain between bask in edition machine room, can prevent what reflect light enters.
(3) Photosensitive plate making process
Photosensitive platemaking method can be used to smear photosensitive adhesive or film processing methods for the different areas of indirect method, direct method and direct method of these three, in essence, there is no difference in the technical requirements of these three screen platemaking methods.