Understanding the principle of a black-and-white laser printer is the basis for understanding color printing. Several image transformations can be used to illustrate its implementation.
Original displacement map. The raster image processor of the laser printer turns the printed page into a bitmap and then converts it into an electrical signal for transmission to the laser scanning unit.
Bitmap variable charge "negative image" In the laser scanning unit, the image point on the page bitmap is converted into a laser signal and emitted onto the imaging drum, corresponding to each pixel in the bitmap, and is emitted when there is a pixel value The laser beam does not emit when there is no value. When the laser emits, a small illumination point is generated on the imaging drum. The imaging drum is pre-charged, and the point irradiated by the laser beam is discharged. The unexposed point still has a charge. After this process, the page position The graph is converted into a "negative image" of the charge on the imaging drum.
The charge "negative image" becomes the toner "positive image". The toner has the same electric charge as that on the imaging drum. The imaging drum rotates. When the charge "negative image" passes through the developing roller, the discharged point absorbs the charged The toner, which is not discharged, does not absorb the toner due to the same sex, so that the "negative image" of the charge is turned into a "positive image" of the toner.
The toner "positive image" becomes a bitmap on the paper. The transfer drum is rotated with the image forming drum. When the charged paper passes through the transfer drum, the toner is adsorbed onto the paper to become a printed image. Since the toner is easily peeled off, the printing paper is passed through a heating roller to closely adhere the toner to the paper.
Editor’s Note: This post was Published by Proffisy on 05 Jul,2018.