Inconsistent printing on CP910

My CP910 printer prints inconsistently. This issue is more clearly represented when I print **bleep** photographs that have 8 on one sheet so I can see tat they are really inconsistent.

For instance certain parts of the photo will have all the colours but other parts especially at the bottom and top will only print yellow or what looks like orange.

Has anyone faced this issue before?

Please, please help.

Thanks