With regards to the paper problem, I refer you to this article, also to the types of paper available,
Personally I prefer a weight of 80 grams xerox performer paper.
Sometimes the original cartridges supplied by the manufacturer are not as well filled as a compatible cartridge. My personal choice is JETTEC, however I leave it open for other readers to suggest their own favorites.
Also have a look at this link, which may suggest a solution.