When the images are blurred or out of focus, almost always it has to with focusing.

1. Make sure the object (i.e. document) fill the screen of the camera and leave the blank black space as little as possible because you want the camera to focus on the document, not on the black cradle underneath it. If there's a lot of black cradle inside the frame and is part of the shot, of course there's a possibility that the camera will look to focus in on the cradle (background) instead of the document (object) that you want to shoot.

2. Use AF mode

3. For AF setting, select "One Shot" setting because that's the most suitable setting for our type of application (shooting stationary object) for "AI servo" was more suitable for shooting moving object and AI focus is the combination of both modes.

4. AF point, select Average.