The jaggies you see are the lines that compose what gets printed. The laser beam sweeps across the drum a line at a time to write the image. Those jaggies are successive sweeps and their printing is offset.
The printer relies on timing to start and stop writing in the right locations to create the print image. The timing is slightly off between alternate lines.
I don't know if the timing is something that is designed to be tuned on that printer. If it can be fixed, it would require a shop with the right equipment.
It is likely you could buy a new low-end laser printer for what it would cost to have a shop open it up and play with it. If you're talking about something better, it would make more sense to put the money toward a new one than invest it in an end-of-life printer.
1The issue looks more like an aliasing problem than an alignment problem. If it is doing it from the self-test, then it is a printer problem rather than a driver problem. This kind of stuff is typically controlled by a program on an on-board chip, which might have gotten damaged/corrupted. It can't hurt to try alignment but if that doesn't work, see if Samsung tech support can offer any advice (even if it is just that they recognize the symptom and can't fix it). – fixer1234 – 2014-11-15T19:05:43.353
I thought it was aliasing at first too, which is why I tried the test page. The printer is long out of support, I thought I would post the question here before looking for a new printer. - by "printer test page" I mean, pressing and holding the button on the printer so that it prints something from its own program. No computer involved. – mgjk – 2014-11-15T20:43:10.503
What do you get if you print an image? Text could use internal fonts, so it could be aliasing (the internal rendering messed up). BTW, just because it is past support doesn't mean they won't offer advice. It just means repairs won't be free if you can get it from them at all. They might recognize the symptom and know what causes it. – fixer1234 – 2014-11-15T21:08:39.427
Good point on the fonts... the graphics are suffering too though. The issue looks far worse blown up in the image above than at scale. I might replace the printer when the toner runs dry. It's time to go for something with built-in duplexing :-) – mgjk – 2014-11-16T00:33:43.377