Print test page perfect / print real doc no blue

[Senior Paper Monitor]

All in the title ....

HP C7280

Prints a perfect test page with black + 5 individual colour boxes absolutely perfect.

Its on WiFi network and have tried several 'real' documents from two PC sources and Cyan appears not to print at all (or certainly only the light Cyan) - all other colours perfect.

Any ideas ?

Has been printing fine for over a year - and have now replaced Cyan and Light Cyan cartridges with new ones.

[Saab Dastard]

Can you test it attached directly (USB?) to a PC?

SD

[Senior Paper Monitor]

OK - will do - will take a while - need to darg it all next door