Germany-based Chromasens GmbH, a leading manufacturer of line-scan camera systems for 2D and 3D machine vision applications, now offers a print inspection system “that achieves unprecedented accuracy by incorporating spectral image capture with 12 individual colour channels per pixel – instead of just the traditional three (RGB).” The fully-automated system combines the Chromasens truePIXA multi-spectral 12-channel linescan camera with the company’s Corona II broad-band line light. Software that mimics the functionality of a traditional spectrophotometre completes the package. The system can be successfully deployed inline or off-line in offset, gravure, flexo, or digital printing – as well as in the colour analysis of printed products such as sheets, stickers, brochures and wallpaper. High-speed colour inspection can be performed over the full-size document or in smaller, arbitrary areas of interest at any stage in the production process, adding to the system’s versatility and value, said the OEM. “Inline checking reduces the number of rejections and lets the printer initiate corrective actions, such as separating defective prints or re-adjusting machines, early in the production process,” said Klaus Riemer, Product Manager for Chromasens. “The result is significantly less waste, lower labour costs, and extremely high speeds.”
The company added that traditional inline print inspection systems are based on basic three-channel RGB (Red-Green-Blue) vision technology that often lets colour defects escape – especially in high-speed web or sheetfed applications, or during longer print runs. In addition, colour checking is often performed off-line in a manual process where a device, such as a spectrophotometre, must come into physical contact with the product it’s measuring. The OEM’s truePIXA and Corona II combination empowers printers to produce higher quality documents at lower costs. Chromasens’ truePIXA cameras feature 12 spectral selective sensors that simultaneously scan printed documents within the complete visible spectrum. The resulting spectral images provide for precise, space-resolved spectral measurements over the entire image, or in arbitrary areas of interest. With up to 3,500 pixels per channel and 21.1 kHz line frequency, the cameras achieve high resolution at speeds up to 6 metres per second. Its Corona II LED linescan illuminator combines superior homogeneity of light distribution with unprecedented illumination strength up to 2,500,000 lux – allowing the truePIXA line scan cameras to operate at far faster speeds than conventional models. Emitted LED light is focused leveraging the company’s patented mirror technology to achieve optimal light shape and spectral homogeneity in the illumination focus range, resulting in no chromatic aberrations.