Flexo-printing technique

As another alternative, the so-called flexo-printing technique has been used for the fast deposition of Au colloid containing coatings on glass substrates of 50 cm x 50 cm in size (Mennig, private communication). The principle of this technique is shown in Figure 29-8. 

Figure 29-9. Au colloid containing coating on glass deposited by the flexo-printing technique with a deposition speed of 10 m/min (right side) having a thickness of220 11 nm and uncoated glass...

Flexo printing is similar to the traditional rubber-stamp techniques that have been in use for hundreds of years. The primary difference is that the flexible stamp (chche) in a flexo process is wrapped around a drum to be used in a continuous rotary process. In order to control the reinking of the cliche, an anilox roller, a metal or ceramic roller with small indentations (wells) of uniform size and shape, transfers ink firom a fountain to the cliche, as shown in Figure 4.6 through Figure 4.8. Diflferent rollers can be purchased to control the amount of ink that is transferred to the cliche. A doctor blade removes excess ink firom the anilox roller before it contacts the cliche. 

Aside from the coating techniques presented here, flexo, screen, and offset printing can also be used to manufacture uniform films in roll-to-roll processes. These techniques are described in Section 4.4. 

Ink-jet printing is slow relative to techniques such as screen, flexo, and offset printing. Performance is improved by using a series of print heads in parallel, often attached to the same positioner, printing a band of the output every time the positioner sweeps across the substrate. The different heads can, of course, contain different materials. 

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