Check the following:

1. A document is jammed.
   Open the top cover and remove the document by pulling it backwards, then close the top cover.
    
2. There are foreign objects in the ADF.
   Remove any foreign objects or ripped paper from the ADF.
    
3. The Document Guides are not set to the correct document size.
   Adjust the Document Guides to fit the width of the document. When Scan Size is set to Auto and you are scanning a document that contains multiple page sizes, insert narrow pages straight and as close to the center of the machine as possible. If the document will not be fed straight, use Continuous Scanning.
    
4. The settings are not suitable for your document.
   Confirm the settings. Choose Long Page from the Scan Area, Page Size or Paper Size drop-down list in Scan Settings, under the Paper Tab when scanning a long document.
    
5. Your document is not acceptable for the machine (for example, if the paper is too long).
   Use the Carrier Sheet.
    
6. Paper dust has accumulated on the surface of the Pick-up Roller or Feed Roller.
   > Click here to see how to clean the rollers.