HP MFP 586f horizontal line when copying from ADF

[ITtech16]

I have an MFP 586 I am working on, every-time a copy is made using the ADF a horizontal line is created on the trailing edge of the scanned document.

I have already cleaned both the bottom and top of the glass strip on the ADF. I have tried to recalibrate the scanner using the printers scanner calibration function. I even tried to replace the whole ADF unit as a last resort but I still get a horizontal line on every copy made out of the ADF. 

Any suggestion would be lovely.

[ITtech16]

Just some added information,

- the flatbed scanner produces no horizontal line.

- Scans made using third party software produce the same result; line present when using ADF, no line present using flatbed.

- tried to hard reset the printer, to no avail

[Repairatrooper]

You need to go to the advanced service menus and adjust the either the scanning size or adjust the trailing edge. I usually program a 2 percent reduction which does not affect the output visibly but eliminates the line.