How a document copier works

1-The entire surface of the cylinder is charged with a positive charge.

2- passes a bright light on the surface of the paper to be photographed and placed on the glass surface of the camera, the light reflects the white areas of the surface of the paper and hit the cylinder drum installed at the bottom

3- When photons collide with reflected light from the white areas of the cylinder surface, electrons are released from the cylinder surface atoms because they are photoconductive. Dark areas on the surface of the paper such as text and images are not reflected by light, making the surface of the cylinder opposite the black areas positively charged.

4-Fine granules of black powder called toner are loaded with a negative charge. The black powder granules are attracted by the positive charge on the cylinder which represents the image.

5- Pass a white paper loaded with a positive charge above the cylinder to attract black powder granules.

6- Heat the paper by passing it on a hot surface to adhere the black powder granules to the surface of the paper.