m277n prints bad

[shlosiii]

m277n started to print bad a few months ago.

I did every step hp recommends to resolve (cleanup, reports etc.), and nothing helped.
All tuners have 40-60%, so it's not that.

The actual problem is that the colors are significantly weak, and there are vertical stripes on the paper.

* I am printing only best quality, and it happens in whatever I am printing from various softwares.

Any ideas?

[Repairatrooper]

Multi colored streaks can be a problem with the transfer belt. Remove the cartridges and in the cavity under them you will see a grey belt. If it has streaks on it them it then there might be a paper jammed in there or a cleaning blade has failed. On another note, a failed cartridge can happen at any time of the cartridges life. Look at the bottom of the cartridges to see if the blue green drum unit is clean with no toner stuck to it.

[shlosiii]

Unfortunately, it didn't work.

There were no stripes on the belt as far as I saw.

I didn't find a way to detach the cartridges tray, so I looked inside with a flashlight, and it seems pretty clean.

Thing is that it's not only the stripes, it's also lack of saturation.

I looked at the bottom of the cartridges, and they also were pretty clean.

I attached 2 pictures- 1 is vivid from before this problem happened, and the other is after.

Any suggestion will be more than welcomed.BeforeAfter