It is a known ccd fault which affected some Ricoh cameras
http://www.ricoh-imaging.co.jp/english/r_dc/info/ccd/
Ricoh Convar service in Germany could replace the ccd for free except for the shipping cost to the service center.
Make sure to put these affected images into the memory card in the camera if you decide to send it in for a repair. The technician might need to find these images to really realize that there is a fault if it not shows up in every image. You could also put that link above into the RMA if you send the camera in for service.
If it have a good sample of that zoom with good corner sharpness and you like the camera enough then sure it might be worth the shipping cost to get it repaired.
But there is other possible inexpensive options as well. As Ricoh Caplio GX8 on Ebay for example. It was a popular camera in its day and still quite ok.
There currently is two of these on Ebay.
http://www.ebay.de/itm/Ricoh-Caplio-GX8 ... 19e49c2a97
http://www.ebay.de/itm/Ricoh-Caplio-GX8 ... 4615bd0226
A good upgrade path from the RX I would say as it uses the same menu-interface and same batteries. AA and the Ricoh DB-43 as for the RX. While the lens is slightly shorter it is better optically and have faster widest aperture at 28mm. f2.5 compared to f3.1 for RX and a little more manual control. The image sensor is bigger as well, 1/1.8" for GX8 respectively 1/2.7" for RX.
The Ricoh Caplio R4 is another good option. A compact super-zoom 28-200mm with fast AF and good image quality though somewhat noisy like the GX8 and also the RX.
One potential problem there could be ocassional horizontal slight banding. But not as serious as you RX shows in the picture and it did affect far from every R4.
I would say that the R3, if you can find one, probably would be as good or better than the R4 despite the older lcd which barely is noticeably except for being somewhat more noisy which can be seen indoors. But the images seemed to be less noisy. The R3 has the same zoom but a 5mp ccd instead of 6mp in the R4. Other than that and the lcd these two are almost identical.
http://www.ebay.de/itm/Ricoh-Caplio-R4- ... 2c76acc2c9
I would advice against the R5 and the other newer R-series cameras like R6, 7, 8 and 10. The R5 was not very reliable and could have known focus-problem at wide-angle. The R6-R7 was even worse as the Phase detection AF had been removed and more enforced noise reduction which destroy fine-details. And the zoom which not is not quite the same 28-200mm as in R3-R4 can get stuck permanently about halfway during the reach due to a wearing design flaw.
The R8-R10 was somewhat better but still had slow focusing. R10 probably the worst due to all the noise reduction which not could be set to Off or even lowered.
R3 and R4 was overall as good as the older the Ricoh super-zoom cameras got and that was not bad at all actually. I still have a R3 which follow with me many times.
The R-series was replaced with the CX series which is ok. But seemingly every of them except for maybe the CX6 seems to struggle with grey-looking noise which makes the pictures look somewhat dull and I've not found a way around that problem unfortunately. The RX which you have didn't have that problem and neither the GX8 or R3-R4.