What could be causing this printer ghosting?

My laser printer is a Samsung CLP-310 and every page I print have these ugly ghosting artifacts:

• A random document I printed and annotated. You can see ghosting happening about 20cm above, and another ghost about 20cm below

• A test document I created to showcase the ghosting in hopefully a clearer manner

• A white page printed after the test page. I had to play with the scanner contrast so that the band artifact are visible but don't trust the color. (i'm not sure this one is related to the ghosting but here it is anyway)

The ghosting happens within a page, and the previous page isn't ghosted in the next page

Original source files:

• test imprimante.docx https://drive.google.com/file/d/1EONEuTJlYRBQDQ5fn5SyWIK3fL9yZv2s/view?usp=sharing

• the other file (screenshot):

Solution 1:

That looks like the drum inside is dirty, picking up toner and depositing that further down on the same page/next pages.

You will have to clean it. You can find multiple instruction videos on Youtube showing how to do that.

Even if this is not the main problem, cleaning the printer will at least eliminate dirt as a cause and make it easier to detect any other problems (if present).