When I use the printer to scan via the document feeder, I get two parrallel lines down the right hand side of each page of the pdf. I've cleaned the glass and everything else but still get the lines. How can I get rid of them and get good scans?

Check your flat bed and Document feeder scanning glass need to be clean, if any dot or dust in scanning glass of document feeder it will appear a line, check this points first
1- Check printouts from computer or FAX if it is clean problem in scanning section
2- Check using Copying a blank paper using only Flatbed if it prints without any line its problem from document feeder Scanning glass
So solution is clean the Document feeder scanning glass using wet cloth, note careful about wet cloth switch off the machine and clean it

CClean The MX882 ADF (Automatic Document Feeder)

Be sure to turn off the power and unplug the power cord before cleaning the machine.

• The power cannot be turned off while the machine is sending or receiving a fax, or when the received fax or unsent fax are stored in the machine's memory. Make sure if the machine completed sending or receiving all the faxes before disconnecting the power cord.
  

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• The machine cannot send or receive faxes when the power is turned off.
  

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• If you unplug the power cord, all the faxes stored in the machine's memory will be deleted.
  

  
  

  Print the necessary faxes or save them to the memory card/USB flash drive before unplugging the power cord.
  

1. Open the Document Tray.
   

   
   

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3. Open the Document Feeder Cover.
   

   
   

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5. With a soft, clean, lint-free and dry cloth, wipe off any paper dust from the inside of the Document Feeder Cover (A).
   

   
   

6. 
   

   
   

7. After wiping, close the Document Feeder Cover by pushing it until it clicks into place.
   

8. 
   

   
   

9. Close the Document Tray. speed printer service
   

   
   

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If your printer has both an automatic document feeder and a flat glass portion for scanning, try scanning from both. If you only get the lines on one of the scans then that is where your problem is. Most common issue on scanners is a liquid paper, bit of paper, glue, etc on the Automatic document feeder glass. Clean the glass and you should be fine.

lift lid on scanner and clean the thin glass on left hand side
you usually find when you scan alot of docs dust builds up and leaves lines down page

Clean the narrow glass strip at the left hand side, under the doc feeder

If you open to document feeder and look at the glass when scanning via flatbed, just to the left will be a smaller piece of glass. That is the glass used when scanning through the feeder. Clean that glass as there is probably a couple of spots on it.

Lift the lid and to the left of the main glass is a smaller glass; that is what scans during the feeding process. Make sure that it is completely clean; even a speck of dust can cause a line to appear. I took a lens wipe and cleaned mine and my line was gone.

There is a tiny spec on the scanner glass. Cleaning it will make the line go away.

Clean the ADF roller and the far left hand side of the glass, the small strip outside the 'main' panel.

If this is happening only when you are scanning using the automatic document feeder, check for something blocking light above the scanner. If you open the scanner top, look along the left side of the scanner glass where the paper is scanned by the automatic document feeder. If you see anything on the glass there, clean it with a soft cloth dampened with clean water.