Black powder coming out of fuser cartridge

[RSauto]

We have a HP Laserjet 700 Color MFP M775. While trying to diagnose an issue with black horizontal lines appearing on printouts I took out the fuser cartridge. Black powder started falling out everywhere.

What is this powder? Is it supposed to be there? Should I blow it out?

Thanks in advance.

[Repairatrooper]

Do you mean the toner cartridge? Toner cartridges load in the front door and the are 4 of them, black, yellow, cyan and magenta. The fuser is located inside the right side door.  

If it is the toner cartridge you removed then that is coming out is toner and if it is spilling out then likely there is a problem with the toner cartridge and it will need to replaced. You also need to clean the excess toner out of the slot in the printer. Do not use compressed air or a standard vacuum as this will disperse the toner into the air. While biologically inert you do not want to inhale it or get it all over the office. Some type of lint free cloth or swifter duster is best . Use no liquids at all, none.

[RSauto]

Thank you for the response. No, it was not the toner cartridge. What I am referring to is located on the right side of the printer as you stated. It is a long cartridge with a black cellophane type film that wraps around the top and bottom. The black stuff (which did look like toner powder through) was coming out of the end of it. Is it spent toner?

[Repairatrooper · Accepted solution]

Ok, that is the transfer belt and likely what you are facing is an overfilled waste toner bin. When you pull the belt out, there is a plastic bin on the end. Some of the first generation belts had a habit of retaining waste toner in the bin and then it would spill out and destroy the wiper blade on the waste bin resulting in direction of feed streaks on prints. You can try emptying the waste toner from the bin to see if you can rescue the belt.  Below is a link to a quick fix article I wrote for another website. Please note that success with this is less than 50% but if it works it will delay you having to purchase a new transfer belt. Also make sure that you update the firmware on the printer after this and also ensure that the printer is level or that the bad side is slightly lower than the front as this can aid in draining of waste toner into the collector on the back of the printer.

https://community.spiceworks.com/how_to/132391-hp-m750-m775-transfer-belt-toner-build-up-and-how-to-...

[RSauto]

Yes, that was it. It looked very similar to the picture in your link: gummed up with a bunch of powder. Cleaned it out and we are now streak free. Thank you for the response!