GEW launches new reflector design for UV curing systems

GEW has launched C3, a new reflector design for its range of UV curing systems. Based on GEW’s retractable cassette system which is easily removed from the dryer housing, this third-generation reflector cartridge has been developed as a replacement to the existing XC ‘extreme cure’ reflector system used on its VCP and eCP product platforms.

As with the XC, the C3 also delivers a fully focused UV output to maximize the UV energy input into the ink. Both reflector profiles were designed using ray-tracing, a computerized modeling program to simulate the effects of different reflector geometries and maximize the amount of UV energy reaching the ink. This has enabled the latest reflectors from GEW to be in the region of 25-30 percent more efficient than others, says the company. However, as a result of additional development work, the C3 also benefits from a number of improvements over its predecessor, notably with regard to its heat management capabilities. GEW calls this a ‘major step forward’ in terms of its versatility and the range of substrates that can effectively be processed.

Three key design improvements have been made over the XC. Firstly, the reflector material is now made up of a specially developed, multi-layered dichroic coating as opposed to the polished aluminum used before. This allows the infra-red radiation from the lamp to be absorbed by the reflector and removed by air-cooling of the reflector’s rear surface; UV radiation is simultaneously re-directed back to the web.  The dichroic coating itself is applied to replaceable reflector inserts as opposed to directly onto the extruded reflector body, which makes them significantly cheaper to replace should they become scratched or dirty.

The second improvement has been the addition of a cold filter, which blocks IR radiation from the lamp and prevents it from reaching the printed substrate, whilst allowing the UV to pass through.

Thirdly, a ‘cold shutter’ has been integrated into the C3 that has eliminated the risk of damage to substrates from heat when the press stops and the shutters close. The single-blade shutter is parked away from the direct radiation path of the lamp when the UV is running, so when the machine stops and it closes, it is cool. A layer of thermal insulation also covers the exterior of the shutter in case the lamps are left on stand-by for a long period of time, which prevents any heat absorbed by the shutter from being re-radiated to the web. When the press re-starts, the shutter opens and moves into its parked position, where it is re-cooled by the lamphead’s internal airflow.

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