There are different methods of paper printing like,
- Gravure Printing
- Flexographic printing
- Rotary Screen Printing
- Lithographic Printing
- Flat Screen Printing
Now all are being described here shortly……………
- Gravure Printing : This method of printing uses solid metal rollers engraved with a design or wooden rollers carrying an engraved metal wrapper ink is delivered via a series of rollers to the engraved printing roller and excess ink is removed with a doctor blade, leaving ink only in the engraved areas.
- Flexographic Printing : It uses water-based inks and is suitable for printing wide papers. The flexographic print roller, also the stereo, is covered with robber or composition and carries the design in relief. The design is cut out using slandered techniques but in recent years laser cutting has introduced. But the printing ink is delivered to the stereo roller by an engraved metering roller to which ink is delivered from the print trough. Thus the raised portons of the rollers are effectively gravure coated and by controlling the depth of engraved the amount of ink supplied can itself be controlled.
- Rotary Screen Printing : When rotary screen printing became widely availble in the textile industry, a demand naturally developed for it to be used also for the production of transfer paper, thus creqationg the possibilites of i house manufacture cutting out the commercial paper printer. Rotary screen printing also has many inrinsic attracttions from the point of view of transfer paper producing such as relatively low capital cost and the capability of printing very wide width.
- Lithographic Printing : Lithographic offers the potential producing photographic quality reproduction. It originally depended on the properties of particular kinds of stone but modern lithographic is based on modifying the surface properties of coated metal plates. A zzink or aluminium printing plate is coated with a light-sensitive oleophilic material. When the plate is exposed to light through photographic color separation negative the exposed areas become cured so that the film can be washed off in the unexposed areas. Thus the design become reproduce on the plate in the pattern of oleophilic and hydrophilic areas. When the plate is wetted with an aqueous fountain liquid the contrast between the two areas becomes so marked that an oil based ink applied to the plate adheres only in the oleophilic region.
- Flat Screen Printing : Although flat bed textile screens printing equipment can be used for the production of transfer paper in the same way as rotary screen printing. The use of flat screens is limited effectively to the production of transfer sheet in standards paper printing machines. These are designed to print large sheets which are cut up later for the production of placements designs or logos for garments panels.