C70 K toner not fusing

[InterfaceP]

C70 customer has that the K toner isn't fusing on any paper weight, and only the K, CYM all fuse as they should. Swapped the fuser, increased the paper weight and none of these solutions have given me any positive result thus far.

Ordered new Developer material and headed there in the morning.

Does anyone have any ideas I'm not thinking of?

Thanks in advance

[adriansto]

Re: C70 K toner not fusing

Counterfeit toner. Developer is magnetic nothing to do with toner. If there are too much toner it does not go into the paper and comes off.

Or the machine have vivid toner kit incorectly installed.