Canon iR C6800 Series Portable Manual page 297

Chapter 5
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2) Place a stack of sheet about 60 mm high over the point of detection of either full sensor on the shift tray.
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3) Select the item, and press the OK key.
4) While referring to the indication, move the sensor closer to the paper, and fix it in place where 'ON' goes on.
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Memo: If 'ON' is not indicated when the full sensor is moved closest to the paper, keep adding a sheet of paper until
'ON' is indicated.
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