I love my HP8710 printer and the InstaInk program, but I was considering shopping for a new printer when I was unable to print on the half-fold greeting card stock (purchased from Staples). I wanted to print some holiday cards using a Hallmark Program, which creates files in a format that could not have been transported elsewhere on a flash drive. I walked through the tips given at this site, including cleaning the rollers. They did not solve the problem. Then I decided to try some different types of paper that were on hand, and I found that the card stock sold by Michaels worked fine. It is heavy enough for a nice-looking card, and there are no issues with jamming. I don't know what the weight is, but it is sold in 50- and 100-sheet packs.