The prints are evenly crossed (RICOH 901s)

[xuonginnhanh36]

Currently I am using a ricoh 901s printer, when prints are printed with evenly spaced strips, is this problem related to laser unit? If I replace the laser unit, what parameters do I need to enter because I do not have these parameters, I'm looking forward to detailed instructions, thank you very much,
Please see the image below

 

[Risu]

Looks like "line raster". Can't you change the raster type or lpi?

 

[Biggs]

You can only change toner dither back to a dot matrix.
Although, unless someone changed in to line screen, that may not be the issue.

Changing of the laser is one service i've never performed, so I can't help much there

I assume the drums and transfer belt are in good shape?