Black ink prints perfect on the test document, but on any other document prints very light purple. Heads are clean?

You still have some clogged heads.Head cleaning once is sometimes not enough to clean your heads properly, especially if you are using 'compatible' ink cartridges. You need to clean your heads again, and possibly still again, until your test print pattern produces the correct colours.

this is usually caused by clogged print heads, unfortunately epson is still one of few brands that still manufactures most of their printers with the heads built into the machine and thus upon print head clogging the printer must be taken in to be serviced or buy a new printer that does not have the print heads built in but rather built into the ink cartridges. hope this helps.

When you go to print on your settings select print in black only. Did you buy Brother ink? Having old cartridges refilled or buying generic can pose a problem. I remember correctly brothers have a chip on the ink cartridge? I have gone through so many printers and its really not worth going any further, seems as though you have put sometime and effort in to this 100$ printer. Take 100$ & buy a kodak easy share all in one the ink is 15$ brand new.

I subsequently discovered that only black would not print - the other colours did. The following solution should work for any colour

Turn on the printer
Lift the front cover so that the ink tanks line up at the front
Move the grey arm to the right of the yellow upwards
Remove the ink tanks (in my case 4)
Carefully lift out the plastic holder for the ink tanks, this I believe holds the print heads
Clean the head(s) using cotton buds and injet refill ink cleaning fluid. I get mine from Tescos with my refill inks.
Replace everything and hopefully your printer will be o.k. Mine was

Always try replacing the ink cartridges first.

It sounds like the print heads in the 7780 are bad. Don't confuse the ink cartridges with print heads. The cartridges fit inside the print heads. You will need to change the heads. Here is a link to HP's how-to.
http://h10025.www1.hp.com/ewfrf/wc/document?docname=c00841890&tmp_track_link=ot_faqs/top_issues/en_us/c00841890/loc:1&lc=en&dlc=en&cc=us&lang=en&product=2512010

Could have the same problem with the Dell.

Hello, this is Harry from www.BusinessSpread.co.uk.
We had the exact same problem when printing, we used 3 different 78 colour ink cartages and they all said 100% full but did not work. We then had a look at the dates on the box and they were all expired so when buying ink from anywhere even PC world or Curry’s always look at the expiry date.
Today I went to PC world and purchased a new 78 ink which said expires July 2011 and it works perfectly fine.
Regards,
Businessspread.co.uk

I find the best way to clean the heads is buy some cleaning cartridges as they have cleaning fluid in them and use them to clean it will take about 10 or more times to clean the heads then put the color ones back in and try again.
Just keep putting it on clean the head don't do a print out till at lest you have cleaned 10 or more times.

Rgs


The StickMan

Clean heads, clean heads, clean heads, etc. Then do the test print to see if the heads are open. I had similar problem with an Epson, had to clean the heads often, finally got to where the heads wouldn't clean so threw it away and bought another one (HP this time, the heads are included in the ink carts, haven't had to clean the heads at all.)

I have the exact same problem, cleaned heads, replaced cartridge, nothing prints, no ink at all no colors or black.

Try this to unclog printhead.
take out cartridge, locate the hole where ink goes trough, put a can of compressed air and blow it.
put some paper under the printhead to catch ink.