Laser printing is an electrostatic digital printing process.
It produces high-quality text and graphics (and moderate-quality photographs) by repeatedly passing a laser beam back and forth over a negatively charged cylinder called a "drum" to define a differentially charged image.1 The drum then selectively collects electrically charged powdered ink (toner), and transfers the image to paper, which is then heated in order to permanently fuse the text, imagery, or both.
As with digital photocopiers, laser printers employ a xerographic printing process.However, laser printing differs from analog photocopiers in that the image is produced by the direct scanning of the medium across the printer's photoreceptor. This enables laser printing to copy images more quickly than most photocopiers.Źródło: https://en.wikipedia.org/wiki/Laser_printing
Solid ink printers, also known as phase-change printers, are a type of thermal transfer printer.They use solid sticks of CMYK-coloured ink, similar in consistency to candle wax, which are melted and fed into a piezo crystal operated print-head. The printhead sprays the ink on a rotating, oil coated drum.
The paper then passes over the print drum, at which time the image is immediately transferred, or transfixed, to the page.
Also, some users complain that the resulting prints are difficult to write on, as the wax tends to repel inks from pens, and are difficult to feed through automatic document feeders, but these traits have been significantly reduced in later models.