Hi, thank you for contacting JustAnswer.com. My name is Russell. I will do my best to provide the right answer to your question.
How old is the printer, please?
What color was the 'mostly grey' image printed supposed to be, when it turned out greenish with banding?
And, was the banding that of greenish over the right color (grey at a guess?) or was it banding of the right color with greenish exceptions?
Thank you for posting that.
I am inspecting the image...
That makes the problem clearer - the yellow areas show no sign of any problem.
Are you using Brother OEM-made cartridges, please, or are they refills/remanufactured/'compatible' cartridges?
If the printer has suffered a period of disuse (or, since the yellow is relatively trouble-free, of disuse of other ink colors than the yellow ink), then that can account for the problem, too.
I advise doing several cleaning cycles (which can be ordered from your printer's Maintenance menu, whether on the computer or on the printer itself), with pauses of at least 20 minutes of complete disuse of the printer while it is still powered On between cleaning cycles.
Then after that, print another Standard Check Pattern, and see if it has improved.
Let me know how that goes, or if you need any instructions on the process.
You may have a defective printhead, then, and it may need to be replaced. But be warned: this could be other problems in the inking system.
Also... what are you printing these images on? if you have changed the material you print upon recently, that could possibly have something to do with this problem.
Was a cartridge change immediately preceding to the appearance of this problem?
What cartridges did you change, what colors, before the prints started going bad after a few good printouts?
But the Black color, and the Magenta, are both clearly troubled... and close inspections reveals a little temporary trouble on one edge of the Yellow block also.
I advise considering the black and the magenta cartridges suspect. And the cyan perhaps also.
Try replacing just one of the black or the magenta. Do at least two Quality Prints, to see if the missing/banding in the color you replace, goes away.
If it works, what of it being not high-tech? Don't you want the printer to print properly?
I would like to ask: What sort of high-tech answer would you prefer, please? a procedure to cure the problem without replacing cartridges? if so, that may take some effort and some time, if it even works, I must warn you.
But if you need such a procedure, I will provide one.