Epson L220 - Stains at the bottom edge

I have an Epson L220 which sometimes leaves some black stains at the bottom edge of the pages. Sometimes, more rarely, at the bottom but on one side of the page. I show you photos:

View attachment 1007
View attachment 1008

Do you know what could be the cause of this issue? The technicians at Epson, in my country, don’t know the cause, or don’t tell me about it, and can’t do anything to solve it.


Also, after a service, it began to print with some horizontal blank stripes. Like this:...

Epson L220 - Stains at the bottom edge