A couple years ago I read that regular printers have something embedded in the ink or ink processing that can identify the origin of printed documents. It was a long time ago, and I think it was Rush who mentioned it.
It is actually edncoded several on each page but you wont find it with the naked eye. It is on the page several times but the components of each incidence are distributed. You will need a strong magnifying lens and you will need to compare like letters. What you are looking for is missing dots. A person who knows what they are looking for can find it in no time. You will have a problem. It has nothing to do with the print head. It is hard coded and is done so that it cannot be flashed. Changing out device memory or processor wont help either. The code is resident where you won’t find it. Laserjets use a very similiar process.
Don’t use your inkjet or laser printer for nefarious purposes. If the power that be want you bad enough the can trace you through it. You could try second or third hand equipment but that be traced as well. Dont forget about fingerprints or DNA - you’re shedding it all the time.