Follow the steps below to improve the scanned image.
The Document Guides are not adjusted to fit the width of the document.
Adjust the Document Guide to fit the width of the document. When Cropping is set to Automatic (Deskew ON) and you are scanning a document that contains multiple page sizes, insert narrow pages straight and as close to the centre of the machine as possible. If the document does not stay straight while feeding, use Continuous Scanning.
The settings are not suitable for your document. For example, an A4 document is fed when Letter was selected as the document size.
Make sure the document size settings are suitable for your document.