Rotary Screen Printing Presses

Unit 6 Equipment and Machinery for Flat-bed Screen Printing

Vocabulary

packaging material пакувальний матеріал

cardboard картон

plastic film пластикова плівка

aluminum foil алюмінієва фольга

compound інгредієнт, складова частина

neutrality нейтральність

odor запах

utilitarian утилітарний

assembly набір

aniline printing друкування аніліновими фарбами

flexible rubber form гнучка форма з гуми

image carrier форма з нанесеним зображенням

viscosity в’язкість, тягучість

aniline dye аніліновий барвник

to dissolve розчиняти

rough surfaces шорстка поверхня

carrier roller несучий валик

cellophane целофан

web tension control system система контролю за натягуванням стрічки

center driven winding unit концентричний змотувальний пристрій

shafted winding unit осьовий змотувальний пристрій

adhesion прилипання

non-absorbent substrate гігрофобна підкладка

register приводка

precision точність

corrugated board гофрокартон

solid board суцільний картон

A screen printing table with squeegee guidance is designed purely for manual operation, and fitted with high-precision

guides on the screen frame holder to ensure accurate positioning of the screen in the printing situation. A vacuum suction plate is used to hold and fasten down the substrate during the printing process. On account of the squeegee guidance, the printing process can be executed with a specified squeegee angle and pressure force. Sheet feeding and delivery are done manually.

Semi-automatic machines enable production capacity to be increased in comparison to manually-operated screen printing equipment. The screen is raised and lowered automatically. On account of a combination of two squeegees, the screen

flooding and the actual printing process where ink is pressed through the screen take place automatically. In this case it is possible to program multiple squeegee operations, if a particularly large amount of ink is re-quired, which is the case with textiles.With semi-automatic machines the feeding of the sheet and delivery of the printed sheet are still done manually on a vacuum printing table.

Fully automatic machines are used in industrial screen printing. They are equipped with sheet feeder and delivery units. Such machines often have several printing units for multicolor printing and an appropriately designed drying line (hot air, IR drying, UV drying).

High printing output (several 1000 prints per hour) is achieved on rotary screen printing machines.There are various designs on the market, for printing web or sheet material.

The combination of a flat screen with a sheet-guiding cylinder, that is, the flat-to-round, comes closest to classical screen printing. The sheet is taken from the feeder pile by single-sheet or stream feeders, aligned, and fed to the stationary printing cylinder.The sheet is held on the cylinder by grippers or vacuum pressure, depending on the manufacturer. Te screen and the cylinder move synchronously while the squeegee remains static. The sheet is taken over by vacuum belts, approximately 90°

downstream of the nip, and either fed through the dryer to the next printing unit or delivered.

Screen printing presses with the most varied drying and delivery systems are available on the market as single- or two-color machines and with sheet formats of up to 1.45m x 1.88m. Printing speeds of up to 3000 sheets/hour can be reached. The metal screen is exposed and developed flat.

The screen is fastened round the open cylinder by means of suspension rails and is also clamped axially. The squeegee is lifted off during printingin the area where the screen is suspended (cylinder gap). Only single- and two-color machines have so far

been made available.

Web-fed screen printing presses use closed screens that are either glued or welded together at the seam or produced as seamless rotary screens. Printing speeds of up to approximately 2m/sec. can be achieved.

A twelve-color textile printing machine is equiped with unwinder, printing section, hot-air dryer, and fan-fold delivery. Seamless rotary screens are used, so that printing can be done without gaps in the image.

The screen printing plate/stencil is produced using thermal writing heads. Special stencil material is used, on which the structure is stabilized by the fibers of the base material. This screen printing system, which digitally images stencils with high resolution (up to 600 dpi) using thermal heads directly in the machine, is used for office applications.

Дата добавления: 2014-12-23