Cannot print black on my brother mfc 420 cn

If you call Brother at 1-877-276-8437 and tell them that your unit is "missing black", they may cover a new printhead under a special warranty. Make sure you tell them it is "missing black" on prints and copies.

try reseating the magenta ink cartridge or replacing it.

this work for me with a mfc 255cw. why it works I don't know but I will continue to use this setting. thank you

Even though I changed the cartridges, my brother MFC 420 CN, is telling me there are no cartridges.

What can I do. How can I solve this problem. They are brand new.

you can purchase the ink here: http://www.brother-usa.com/accessories/Accessories.aspx?Model=MFC420CN&ACASCID=30
you can download the software for your Brother MFC 420 CN printer here: 
http://welcome.solutions.brother.com/BSC/Public/Templates/DownloadTop.aspx?NRMODE=Published&NRNODEGUID={2C7B4D65-D5B3-47BF-958E-322BE5EFDCA8}&NRORIGINALURL=/bsc/public/us/us/en/dlf/download_top.html%3freg%3dus%26c%3dus%26lang%3den%26prod%3dmfc420cn_us&NRCACHEHINT=NoModifyGuest∏=mfc420cn_us®=us&c=us〈=en

I wouldn't be surprised. Since you're going to need black ink eventually anyway, put in a new black cartridge and find out.

If you have indeed cleaned the encoder strip, you might as another troubleshooting step check the alignment:

Brother MFC 420CN User Manual Checking The Printing Alignment

Having had the same problem on my 425cn Brother with the black ink, I'm told that the solution is hot water. I goes something like this: remove cartridge, place in container with hot water for a while, remove allow to dry completely, replace, perform clean cycle and print test page. Apparently it's imperative to dry completely and stand cartridge upright. The warm water thins the ink, and remove (apparently) blockages. I cannot verify that this works, but will try it this weekend and let you know! If the housing that the ink cartridge can be readily removed, take that out and clean in warm water. Again dry very well before returning. Be care full that ink becomes runny and may leak out of cartridge and make a mess - so work carefully.

Use another new genuine (original brother) BK cart. Do the cleaning twice only for BK. Wait some time (4 hours). If the ink has dryed up, the cleaning ink will break up the dryed one. Do the cleaning again. If it doesnt work, please write again.

the brother printer is not a good brand i also have a brother mfc 3220cn and it gives the same problem, what you have to is unplug the machine and let it stand for about 2 days take out the cartridges and clean the printing with air replace back them and plug in.that should remedy your problem.i urge on you never to buy brother printers.if you buy them get a bottle of phensic along with it.good luck my brother.