Suddenly these red dots appeared on the printed pages. Not all, but most, including the pages I wanted to "delete". I thought it was a problem with the drum cartridge? nope I pulled out the red toner cartridge and checked for "leaks". seen a few and used kleenex on them. The red dots are gone. for a while, then back again. The printer said the cartridges were only half used. but I was frustrated by all of this (even running that wire cleaner back and forth - no change). So I bought a set of cartridges from another manufacturer and just installed them. after a few pages everything looks fine. Let's see if this problem comes back, but I doubt it. I noticed that when changing to new cartridges, there was red powder on the yellow old one. looks like a leak again.