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.

[PGS]

Exact same issue over here. I bought a PIXMA IX6850 a year ago and it had always printed wonderfully.
However, about a month ago, it started printing very noisy (the first and last few centimeters of the page), and now the noise appears on the entire page.
I have spoken to Canon customer service and they can't tell me what is wrong.

I have also tried everything you mentioned, including changing the brand of ink and the print head.

Were you able to fix it in any way? I'm desperate

[Ron]

Welcome to The Canon Community PGS. 
We appreciate your participation, however, we need to let you know that the Canon Community is hosted and moderated within the United States by Canon USA. We are only able to provide support for Canon products manufactured for and used within the US market.  The PIXMA IX6850 isn't sold or supported by our team here at Canon USA.
If you live outside the United States, please CLICK HERE and select your country or region for your support needs.
You're welcome to discuss Canon products sold outside of the United States, but please be aware that you will not receive support directly from Canon USA.