WF-2660 consistently print white gaps

[Sebastiano Alighieri]

hello all,

i have an epson 2660 which has been working very nicely up until today.

we recently changed the blk cartridge (220XL) - this is when it started to exhibit this issue.

i've completed several nozzle checks, print head cleaning, print head alignments - which all look good.

still, upon printing text or images, the printer consistently prints a white strip / gap.

i've attached an example of each.
note: in the image printout, the issue is with the highlighted horizontal gaps. any other white space is part of the image.

anyone ever encountered this issue and, more importantly, how was it resolved?

much obliged.