Printer output is deep blue

[ConradP]

Recently the machine has "overprinted" the entire sheet a medium blue.  That is, the type is black BUT instead of the rest of the page being natural white, it's edge-to-edge deep blue.  (No, it's not loaded with blue paper!)  

But oddly a *few* pages do still come out white whenever I print *them*:  the Wireless Network Test Report, for example.  

It also works fine for "black" photocopies; "color" has blue 'spray' even if the original is plain white. 

So far I've reset to Factory Defaults, run a couple of Clean cycles, and it's done a Calibration.   

What next?

[Repairatrooper]

Most common cause is a failed cyan cartridge, very common with off brand cartridges and when cartridges approach very low status as the seals just wear out. If this is an HP OEM cartridge and the cartridge status does not read very low it should be covered by warranty.

[ConradP]

To be sure I understand...a failed cyan cartridge might spew cyan ink everywhere?  Like a valve that won't shut off?  Thanks!  

[Repairatrooper · Accepted solution]

That is correct and when printing straight black pages the color cartridges are alienated so they are not touching the transfer belt and hence no transfer. If you remove the cyan cartridge and examine the blue-green drum on the bottom you will likely see excess toner on either the drum or the cartridge body around the drum.