Why are there no real open source hardware printers? Some parts should be similar to 3d printers, probably the print head (for ink) or toner roll/drum (for lase

Why are there no real open source hardware printers? Some parts should be similar to 3d printers, probably the print head (for ink) or toner roll/drum (for laser) will be quite difficult. I saw some tries on hackaday etc, but no real printer with 100% open source & open hardware. Does anyone know a project building that?