Print comes out very grainy (Printer PIXMA ix6820)

[Luna1]

Initially, my printing experience boasted clarity and precision, aided by high printer settings, but now I am printing noisy/grainy printed images.

Things I did: (On new ink) meticulous maintenance procedures such as head alignment, deep/regular cleaning cycles, and cleaning encoder strip with alcohol --> the resultant prints exhibit an unexpectedly grainy texture. Even after fixing images at resolutions of 300 to 600 DPI in Procreate/Adobe with noise reduction settings at maximum level, the issue persists, confounding my customary workflow, which previously yielded high-quality results.

[Luna1]

The print quality used to be excellent at the top, but now it's noticeably worse at the bottom. I doubt it's because of the program settings since I've always printed in high quality.