HP LaserJet 4100 Service Manual - Page 60

The CPB controls the following scanning-process control signals: q ADF unit and scan unit operation • directs the scanner controller board about when to scan • directs the scanner controller board about how to scan • directs the scanner controller board about when to activate motors • directs the scanner about when to turn the scanning lamp on and off q Image processing • color alignment • resolution conversion • image sharpening • moire removal • image scaling • shifting of data strips (reconstructing separately processed image data before CPB communication to the formatter) • RGB conversion for CPB communication • CPB communication over the high-speed copy connect cable to the formatter in one of the following formats: • Hardware Ready Bits (HRB) (fastpath) communication with the hard disk on the formatter • PCL-XL (N-up, rotation, book mode) communication with the hard disk on the formatter • JPEG compression (when sending data digitally) communication with the hard disk on the formatter • data compression before sending to the formatter over the high-speed copy connect cable Typical scanning-process flow 1 The original document is placed on the glass or in the ADF. 2 The user selects job preferences by using the control-panel buttons and keys. The user presses the START button. Job preferences are sent to the formatter. 3 Some job preferences are held and then processed later (for example, N-up) by the formatter. Others are sent to the CPB. 4 The CPB sends control signals to the scanner controller board. The document is scanned. 5 The scanner controller board sends scanned-image data back to the CPB. 6 The CPB processes the image. 7 The CPB sends the image data to the formatter. 8 The formatter further processes the image data (if required). 9 The image data is then either printed or sent digitally, depending on what the user specified at the beginning of the process. 58 Theory of operation C9148-90909