Samsung MultiXpress K4 Series Service Manual page 75

2. Product Specifications and Description
8) Paper size sensor
This detects the paper size on scan glass automatically. It has 2 sensors. It uses the infrared LED to detect the dark original.
9) Home sensor
This is to detect the FR carriage position. It is a transmission photosensor.
10) Cover open sensor #1
When the ADF unit open and close, this has trigger function to detect the on/off of paper size sensor. And this detects
the width of the original.
11) Cover open sensor #2
This is the reed switch to detect that the ADF unit is closed. It uses the magnetic force for ADF close detection.
12) ADF glass
ADF glass scans the original through ADF unit. When the original passes on this, FR carriage reads the original. If it is
contaminated, the horizontal black line or white line can be created.
13) Shading sheet
This makes the scan module detect the base for white color. Before every scan-job, scan module reads the shading sheet to
scan image as same color and brightness. If it is contaminated, the vertical image can be created.
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