What causes black dots on the things I print out on my Laserjet?

Question

What causes black dots on the things I print out on my Laserjet?

Answer 1

Several possibilities. 1) the drum was exposed to light or scratched as toner is getting stuck to the scratched or exposed area. The only way to fix this is with a new drum. 2) the brush which is supposed to remove the excess toner is not perfect (it's missing some bristles or separated) and thus it's not removing all the excess toner.  3) the corona wire needs cleaning. This is usually a very simple operation. Read your printer manual for how to do this.