Photo print problem on plain paper

I have a Kodak ESP-3250 printer which I originally thought was causing vertical evenly space lines on photo prints. No, it is not the printer, it is the paper! Photo paper prints are just fine!

When I print on plain paper so that the project can be quarter-folded for notecards, the photos have the vertical evenly spaced lines on them.

I am using plain 24 lib. paper to keep costs down. I've tried 28 lb. paper with same results. Photo greeting card stock and photo notecard stock are too expensive for this project plus the results are not much better.

In other words, I really just want to use regular 24lb paper for the photo project if I possibly can!

I would appreciate any suggestions you might have regarding paper, printing and/or printer.

Thanks for your help.
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Vernon