On Thursday, March 26, 2020 at 8:58:59 AM UTC-4, Miguel Giménez wrote:
Good morning

When I print a page my HP Laserjet 3800n often picks two or more paper
sheets from the tray. I have been googling for this problem but I could
not find the magic words to get a valid result.

I suppose it is a cleaning problem, but I prefer asking before dismounting.

Thank you in advance.

--
Saludos
Miguel Giménez

how many sheets usage is on the pickup rollers? If over40K, good idea to replace them.
HP makes maintenance kits for refirbing the units. Read the service manual and see what are recommended maintenance items in the paper feed mechanism..
Oh, and ALWAYS keep the paper reams in a low humidity place and 'fan' the pages from both sides and top+bottom before the paper is placed in the tray.
good luck
j