Canon CANOSCAN N1220U Service Manual

Also see for CANOSCAN N1220U: User guide User guide Getting started guide Getting started

CHAPTER 22 - 12 COPYRIGHT  2000 CANON INC. CANOSCAN N650U/N656U/N1220U REV.0 JUNE 2000 PRINTED IN JAPAN (IMPRIME AU JAPON)B. Document Scanning SequenceFigure 2-9Table 2-1HPDET STUP SCFW SCAN SCRTNSTBY STBY(A4, 1200dpi, 100%, 24bit color)8 sec.SEQUENCETimes required (s)Drive motor (M1)LED ON signalInterface signal(Data 1-8)Scan command is receivedScanning unit positionHome positionBorder betweenblack and white: ReverseDocument scan areaAfter a power on sequenceis completed until thescanner receives a scancommand from the hostcomputer.To maintain the scannerready for scan.After the scanner received ascan command until thehome position is detected.To detect the home positionand a border between blackand white.If the border detection betweenblack and white is failed, thescanning unit stops there andproceeds to the next step.After the home position isdetected until documentscan starts.To make a gate array setting,buffer RAM initialization, etc.as a preparation for scan.After the scanning unitstarts moving forwarduntil it reaches thestarting position of thescan area specified by thehost computer.To move the scanning unitwith a uniform speed to thevertical scanning positionspecified by the hostcomputer.After the scanning unitstarts scanning until allarea specified by the hostcomputer are scanned.To perform various imageprocessing according to thecommand from the hostcomputer and transmit theimage data during scan.After the scanning unitstarts moving backwarduntil it returns to thehome position.To return the scanning unitto the home position toready for the next scan.The home position is detectedby the home position sensor.SequenceSTBY(Standby)HPDET(Home positiondetection)STUP(Setup)SCFW(Scanning unitforward)SCAN(Documentscan)SCRTN(Scanning unitreturn)Purpose Remarks