data swap
keep in mind that this diagram is for a jv3 160sp. if you are at all confused about transposing this diagnostic tool to a different slider board, ask around first. it's not difficult, obviously, but should be done properly.
(this diagram is for a machine with four dx4 heads.) diagnosis goes as follows. if the data is the issue, than you can put different data into that head. the printer will know nothing of the position of the print head. the color will print a half inch off of its normal position because it is now printing to the wrong x/y coordinate on your substrate.
not only will it show if you have a bad head, or bad slider board. but also prove if you have bad cables, etc. basically use the process of elimination to isolate the issue.
the fact that you used so much of that head and it printed fine up until the next morning is suspect of something not data related. when you pull ink through the head via the cap/tube beneath the head. do you get even gentle flow? or a more solid difficult pull, unlike the head that is printing?
when doing your head cleans, is there the proper amount of latent ink sitting in the cap as usually seen? i'd suggest a damper swap, but the fact that both colors are gone negates a possible ink supply issue.