The image data is collected in the scanner formatter where it is processed and sent to the formatter. The formatter then handles the image data, outputting it as a copy, sending it through the LIU as a fax, or directing it to the computer as scanner output. The image data collected is 600 pixels per inch. Each pixel has 8 bits for each of the three colors (256 “grey” levels for each color) or a total of 24 bits per pixel (24-bit color). Scanner Operation Upon power-up and periodically at other times, the scanner assembly moves systematically to locate its home position. It then calibrates itself to a white label located under the glass at the right end of the scan tub.
If a document is detected in the ADF when a copy or scan is initiated (from software or control panel), the scan module moves to the left side of the scan tub and stops. The image is acquired as the paper is fed through the ADF past the scanner module. If no document is detected in the ADF, or if the model does not have an ADF, the scan module acquires the image from the flatbed glass while slowly moving within the scan tub. ADF Operation Standby (paper loading) mode: In standby mode, the pickup roller is up and the stack stop is down, preventing the user from inserting the document original in too far. When a document is inserted properly, it is detected by the paper-present sensor.
The standard operation of the ADF consists of the pick, feed, and lift steps. Pick: Upon receipt of a copy or scan command, the ADF motor engages the gear train to lower the pick roller assembly and raise the stack-stop. The first roller is called the pre-pick roller and serves to move the top few sheets forward into the ADF. The next roller is the pick roller. This roller contacts the ADF separation pad which separates multiple pages into single sheets. Feed: The single sheet continues through the path. Along the way, it is detected by the form sensor a set distance from the ADF glass. This alerts the scanner to start when the page reaches the glass.
The scanner acquires the image, one raster line at a time, until the end of the page is detected and the page is ejected. The pick and feed steps are repeated as long as paper is detected in the ADF input tray. EN Scanner and ADF functions and operation 81