Yellow background on my rpinting

[helgaw51]

I bought a Laser Jet Pro M477fdw in January this year. We use several devices to print from.  From all of them we are now getting a yellow background on most printing and photocopying.  I have changed the yellow cartridge as some one suggested elsewhere but that has only improved things slightly in that the yellow is not so intense now. 

If I photocpy in just black there is no yellow. 

I have run the cleaning page and there is yellow on that.

Any further suggestions or do I need to get my printer changed as it is still under warranty.  I bought direct from HP ie.

[Valsimot]

Smells like yellow toner cartridge.

Are you using genuine HP toners or remanufactured?

[helgaw51]

Yes I only use genuine HP consumables.

And yes I have already changed the yellow cartridge once (as per my original post) and although it has improved a little it is still a yellow background.  

I will be telephoning HP later to talk to some one there.

[Valsimot]

Can you print then scan supplies status page and post here so we can see?

[helgaw51]