The drum is first electrostatically charged. Then the light image is focused on it. The photons change the charge level on the drum. Then the drum is exposed to the toner. The toner sticks to the drum by the electrostatic forces. Then the drum is rolled onto the paper which transfers the toner to the paper. The paper is then heated which makes the toner stick to the paper.
This is how all xerographic methods work. I was explaining the standard Xerox machine from 40 years ago.
Now I understand your question. The paper is put on a rotating drum and the ink source is moved the perpendicular direction. This way you get a raster scan. The ink source is very much like an ink jet printer.
This is very much like the wire photo method invented by a person in Canada around 1925 and used for decades by news papers to obtain their photos.
I can explain ( I saw it inside ). one side of fiilm is placed on drum , and with air underpressure it is unmovable from the drum. There is laser head over drum ( in my case 256 row of laser LED ). and this head is moved from beginning to the end of row without changing position of drum. after that drum rotates and another row is made. That's all. If you have more question s you can ask.
It looks like there are many ways to do it. The one I described is from a product that is used for making production, press ready art work for magazines and books.
The demonstration I saw also included a morphing program which was used to alter photos of women modeling clothes so that their legs and waists were made to have a smaller diameters. So much for the old folk saying that the camera never lies.