Image Problems Most image problems are caused by a bad toner cartridge. If you have a shot, the light / dark areas or spots over and over again on your print, replace the cartridge and see if it is resolved. This is common when using bad cartridges again. Some scavengers do not replace the image drum and they should be because the drums originally only designed to last for the expected life of the toner. If problems persist after replacing the cartridge the next area to look would be the fuser. Hot rollers can become torn or warped after a period of time causing an image defect.
Maintenance Kits On most new printer, HP has set the average life span of spare parts and has a maintenance message is programmed to appear after a certain number of pages have been generated. The message would be something like "USER MAINTENANCE PERFORMANCE" depending on what model you have. This is only a rough estimate. Some parts may go before this message appears and some will last long after. You can get a maintenance kit which usually contains fuser, feed rollers and certain parts of the other high mortality depending on the model. Newly designed to be user replaceable and does not require a skilled service technician to install. This is a good idea to have one because this kit will usually take care of most problems you'll ever have.
Paper, Envelopes and Labels The quality of what you feed into your printer can also be a factor. Some types of paper can cause feeding problems. Envelopes and labels put more load on the engine than plain paper. Be careful with labels such as these can sometimes slide off the fuser or toner cartridge. Humidity and heat can also be a factor. A moist environment can cause paper to feed you to absorb moisture causing the problem. If you turn off the heat or air conditioning at the weekend, allowing the temperature of the room to return to normal before you start work.