SCREEN


Rolt Roll-to-roll applications range from biosensors to decals


One interesting addition was a new stencil reclamation system that used no chemicals and provided a completely clean mesh using water pressure of up to 8,800psi. The system works using mega pressure water ejected onto the coated mesh by what looks like a shower head that consists of a single row of jets. The head traverses across the coated stencil and rotates as it does so, such that every part of the emulsion is impacted by what can best be described as liquid lasers. Jets of less than a millimetre direct massive hydraulic forces on the cured emulsion and completely remove it from the mesh. Remarkably there is no damage to the mesh that is left free of any debris.


Benefits of the system, which was designed by a team with a high pressure control background, are that it uses zero chemicals and has a price below many stencil reclamation systems. It can remove cured and uncured ink, but this has to be filtered out of waste water before disposal into the sewerage system. The company also offers a frame cleaning system that removes cured adhesive at a monstrous 24,000psi.


Safe and dry


Natgraph, a producer of screen printing related products in the UK, also presented some key new products in the form of ultra efficient dryers. Recognising that drying and curing determine the speed of print, the dryer can control print speed and even provide the power supply for the printer. All this adds up to efficient printing, which is the most environmentally friendly option of all. The company's exposure unit with a 450 exposure surface took centre stage.


Alan Shaw of Natgraph explained how the Visit us at www.spdi-online.com


ScreenReader is able to measure the developed image on the stencil


unit had been designed to take the guesswork out of stencil exposure. This equipment can actually maintain the surface temperature of the glass and will remove the effect of heat on the size of the photopositive. The angled glass increases the distance from the UV light source, which in turn virtually eliminates light scatter.


Rolt Marketing's Richard Rolt was cautious about exhibiting his specialist roll fed screen printing systems, but was delighted with the results. His current offering combined his most advanced printer and drying system yet. The company has maintained a healthy order book, having recently completed a biosensor production line, a decal manufacturing line and with a thermal transfer and further multi-colour decal lines in production. Nearly 90 per cent of Rolt’s production is exported. As well as producing standard machines, Rolt will satisfy a client's impossible demands with innovation. As always drying and curing governs print speed, but highly efficient specialist dryers can provide extended drying lengths in a relatively small footprint.


Missing link


Other products to make a splash at Fespa included the ScreenReader stencil calibration instrument, which received a significant number of enquiries. Previously it has only been possible to measure the origination and the final printed image, so the ScreenReader fills the missing link by being able to measure the developed image on the stencil. This allows the printer to measure the key elements of the process, starting with the photopositive then the stencil and finally the finished print. With this information, adjustments can be


made to the RIP to provide a specific standard, either a litho standard, or simply consistent colour reproduction. When computer to screen is used, the system is even more valuable as there is no photopositive to measure. The software included with the ScreenReader produces correction curves data that can be fed back into the RIP resulting in a print output to whatever standard you require. Of course you have to be consistent in your press settings and ink densities.


Small Products went big at Fespa 2010 with particular interest in the company's range of special effects inks manufactured in the UK. Few people are aware that the Sensations special effects book produced by Fespa was largely printed with Small Products screen printing inks. Managing director, Dak Patel, was delighted to explain how his special effects screen printed inks could help the printer sell his product at a premium price. Interest came from all over the world and resulted in firm orders.


Even the giant Sun Chemical was pushing its new range of Sun Promo inks for indoor and display materials along with screen printing inks for containers, optical discs, IMD, glass and plastic cards. Then company's Robin McMillan explained: “Sun is developing next generation inks and staying ahead of the curve. Screen printing inks are a key element in our development going forward and there is more to come.”


Across the board there was enthusiasm and optimism about the future of screen printing. The message: just watch this space.


Tel: 01226 770772 Email: peter.kiddell@pdsinternational.com August 2010 l SCREEN PROCESS AND DIGITAL IMAGING 15


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