This is, almost certainly, a failing lamp. You are, maybe, in luck. Most of today's scanners use something called a Cold Cathode lamp. The older style scanners used a special lamp with a high CRI (Color Rendering Index) which uses a wider spectrum than your usual house lamps. As lamps with a high CRI are not generally replaced (disposable society and all that) there is not a very large market for them. You do see replaceable lamps but that is generally with the more expensive scanners, those used in a professional setting where they pay a great deal of money and often have a specialist company maintain their print rooms (which is often where the scanners are).
Now, this doesn't mean you're entirely out of options. You can do a few things to resolve this situation, maybe:
You can find a forum, if one exists, full of enthusiasts. I did not see one for your model. You may have better luck than I. One of them may be able to find a lamp or know where you can find one.
You can try the myriad online resources in hopes of finding a working model that matches your own and harvest the lamp from that one. It's not difficult to change your lamp and, believe it or not, this may actually be your least expensive and most viable solution. You do need to make sure that it is not a Cold Cathode first. (More on that below.)
Finally, you can call the manufacturer or use their online contacts and see if they will find, sell, and help you change the lamp. Having dealt with this company in the past, I wish you luck.
Now, assuming that Google is correct and you do, indeed, have the older style lamp (the newer lamps are not user-serviceable) then you can try this site to get the current contact information for user-serviceable parts replacements. They should be able to tell you if it is a Cold Cathode or a CRI lamp.
If they can give you the part number there's a very limited chance that a specialty lamp shop will carry this. As you have a consumer model, there doesn't seem to be a detailed technical spec chart online.
Sorry that this is, unlikely, an operating system issue and can't be fixed by tweaking and poking. To be honest, the lamps are expensive and it may be worth it to simply replace it with a newer model if you can't find a cadaver to strip for parts.
I've gone through this, albeit with a different model, myself and my scans looked a lot like the one you're sharing with us. I wish there were more to do but it's almost certainly a hardware issue.