Online printability prediction for gravure paper and board

The Metso IQ Surface sensor mounted on a scanning frame measures the surface quality of the moving paper sheet using high-speed image capture and analysis technology. The high resolution camera takes rapid snapshots of the sheet illuminated in different directions by the flash of several solid state light sources around the camera. Surface analysis is achieved with the sensor's sophisticated image analysis which defines all surface quality parameters. Trials at a Finnish fine paper mill together with local print house during normal production run have given excellent results in predicting the rotogravure printability with IQ Surface and provided valuable insights into the mechanisms involved. Predetermined test fields of several half-tone colors were printed in a brochure, then scanned and evaluated with PTS Domas image analysis software. No significant amount of missing dots was found on any test field other than the 5%, where the highest measured was 50 missing out of 9,000 dots per cm 3.