Toshiba’s latest is for scanning shiny objects

Louise Smyth

Toshiba Electronics Europe has just launched a new lens reduction-type, 5340 pixel by 3 line colour CCD linear image sensor for office automation and industrial equipment that realises 24 lines per millimetre resolution for an A4-size document.

More and more users want A4-size multifunction printers that can deliver the same high image quality and high-speed operation as A3-size models. This is especially true for scanning objects other than documents such as three-dimensional objects with very high reflectance and other types of shiny objects. Scanning these objects with conventional lens reduction-type CCD linear image sensors often results in blooming of the sensor and horizontally streaked images. As a result, the output signal voltage of the sensor in the blooming area often exceeds the maximum input voltage range of the analogue front-end IC.

Toshiba’s new TCD2569BFG offers less colour registration by reducing the spacing between pixel arrays (red-green, green-blue). Each of the pixels in the 5340 pixel by 3 line array measures 5.25mm x 5.25mm. A built-in sample and hold circuit lengthen the video output signal period of the sensor and contributes to easier design of high-speed scanners for use in office automation equipment and industrial equipment. Additionally, 4V saturation output voltage in the CCD shift register reduces any blooming. Installing a clipping function via a clamp circuit ensures the output signal voltage is held below 1.8V, which prevents output signal voltage from exceeding the maximum input voltage range of the analogue front-end IC.

The device operates from a power supply in the range 9.5V to 10.5V and can operate at frequencies up to 35MHz.