Print quality issues

[xpcart]

The print on each page is leaving a yellowish background ahon the paper. I have changed the yellow cartridge and the black, but that did not change anything.  I think the yellow is being transferred from the transfer belt, since I have pulled the transfer belt and saw yellow toner coming out of one end of it. Is that normal, for a transfer belt to pick up toner and dump on the paper

[Repairatrooper]

You will see this issue if the waste toner bin on the end of the printer is full and toner is backing up onto transfer belt. If you remove the transfer belt, on the left front side (front being the side the goes into the printer first, there is a little shutter that opens. Normally waste toner moves out of the waste bin into the waste toner bottle in the front of the machine but sometimes the toner does not move properly and backs up. If you hold open the shutter and shake the transfer belt over a garbage bin and you see quite a bit of toner come out that might be the case, but typically if this is the problem the streaks will be a muddy color not a single distinct color. Single distinct colors defects are usually a cartridge related issue and it is possible to get 2 bad cartridges in a row, especially if you are using non-HP toners.