So speckling might not be the best description, but I'm not sure what else to call it. Neither am I sure if this is the right place to ask this question, so if it isn't, please direct me to a better location.
The speckling can be seen best in the orange/yellow part at the top of the image, though you can really see it throughout. Notice the regular color dots; that's the speckling that I am referring to. I'm using a Mustek A3 1200S Large Format scanner, and nearly every image is speckled. (Maybe 1/50 doesn't have it). The level of speckling varies. Sometimes it isn't too noticeable, and sometimes it completely alters the image. I've noticed it seems more pronounced on oranges.
My question is two-fold: What is causing this, and can I fix it (without buying a new scanner)?
P.S. Again, I apologize if I'm in the wrong place. It was a toss-up between here and Graphic Design SE. Thank you for your time.