Chapter 55-19Advise the user to clean the area where the CCD stops in stream reading if the message has appeared.SERVICE MODE:COPIER>OPTION>BODY>DFDST-L1 (level 1)use it to adjust dust detection level between sheetsCOPIER>OPTION>BODY>DFDST-L2 (level 1)use it to adjust dust detection level at the end of a job5.3.5.3 White Plate Dust Detection Control 0011-2231The white plate can collect stray dust inside the reader unit, causing lines in images, and the machine isequipped with a mechanism to check for dust on the plate and correct it to limit its effects on output images.Timing of Control1. Before a Job- white plate dust detection- white plate dust correction2. After a Job- white plate dust detection- white plate dust correctionF-5-41Particulars of Control- White Plate Dust DetectionThe machine compares the data on the light reflected by the white plate at time of fixed shading and shiftshading to check for dust on the white plate while at the same time identifying the coordinates and widthof the area of dust.- White Plate Dust CorrectionIf the machine detects the presence of dust, it corrects the shading correction coefficient of the area of dustby means of a correction coefficient used for both sides of the area with dust, thus limiting the effects ofthe dust.F-5-42Dust detection control Dust detection controlStart keyON1stSCAN2ndSCANCorrection AlgorithmData on light reflectedby the white plate(shift shading))Data on light reflectedby the white plate(fixed shading)Identifies the coordinatesof the start of dust and widthThe machine corrects the correctioncoefficient of the area of dust using datafor areas on both sidesPoint of white plate datameasurement at time of fixed shadingWhite plate data correctionarea at time of shift shadingWhite plateDustComparison
