The alignment page will continue to print until the alignment is complete. Put the page on the scanner face down on the glass. (Make sure the alignment page printed on plain bright white paper (A4 or letter). Also correctly orient the page on the glass - the section with black squares should be to the left.) Press the scan button and wait until the power button stops blinking.
If the alignment page continues to print, remove the ink cartridges and inspect them. You want to look for any debris (including part of the tape that kept the ink from drying out). Replace the cartridges and check if the problem has been resolved. Do the complete alignment again.
If it persists, clean the electrical contacts with clean water (distilled or bottled) and cotton swabs or lint free material (coffee filters will work). Remove the cartridges and then unplug the printer. Dampen the swab (or alternate material), squeeze out any excess moisture. Hold the cartridge by the sides and wipe the copper-colored contacts until no excess ink is present. Place the cartridges with the nozzles facing up on a clean sheet of paper. Repeat this for all of the cartridges. Then clean the copper contacts inside the printer. Let dry for 10 minutes and then reinstall the cartridges and plug in the power cord. Do the complete alignment.
If the problem persists, try new ink cartridges followed by resetting the printer (preferably you should reconnect at an outlet on a different circuit). The reset procedure: turn on the printer and then remove the power cord from the printer. Unplug the power cord from the wall outlet and plug in directly at a different outlet. (no power strips, surge protector or extension cord) Load the paper tray with plain white paper (letter or A4). Plug the power cord into the printer. Turn on the printer and do the complete alignment again.
If this step doesn't solve the problem, then the printer needs service. It is not keeping the alignment in memory.
Refilled or remanufactured cartridges can be involved in the problem. The printer usually remembers the alignment when a cartridge is removed and reinserted. Clogged nozzles on an ink cartridge can also be involved.
I hope this helps.
(for pictures and more details see: http://h10025.www1.hp.com/ewfrf/wc/document?docname=c01336348&cc=us&lc=en&dlc=en&product=428800&tmp_track_link=ot_search