Phaser 740 White Patches only on Black

[nidash]

Hi,

i have a phaser 740, i am facing a problem with it. On a service print on the Black page, it shows a white patch on the same location, i tried changing a black cartridge to no effect.

have seen the imaging unit, the fuser but nothing seems to have stuck inside too, cant figure out what is the problem, can someone help.

Nida

 

[nidash]

i hv now changed the imaging unit, this has solved the problem.