Working principle of copier

The working principle of the copier is to use the potential characteristics of the photoconductor to charge the photoconductor when it is not illuminated, so that its surface is charged evenly, and then the original image is imaged on the photoconductor through the optical imaging principle.

because the image part is not illuminated (equivalent to dark state), the surface of the photoconductor is still charged, while the image-free area is illuminated (equivalent to bright state), so the surface charge of the photoconductor disappears through the grounding of the substrate, thus forming an electrostatic latent image.

then, through the electrostatic principle, the electrostatic latent image on the surface of the photoconductor is transformed into a toner image on the surface of the photoconductor by using toner with opposite polarity charges. Finally, the toner image on the surface of photoconductor is transferred to the surface of copy paper by electrostatic principle, and the basic process of copying is completed.

Extended information

The working process of the copier mainly includes the following parts: (in copying order)

1. Charging components (high voltage generator, electrode holder, motor wire)

Make the surface of the photosensitive drum uniformly charged.

2. Exposure components (scanning exposure lamp, reflector, lens)

Make the surface of the photosensitive drum conform to the original image, and form the reverse potential latent image of the image.

3. Developing parts (developer, high-voltage generator)

Convert the potential latent image on the surface of the photosensitive drum into a toner image.

4. Paper feeding parts (motor, paper pick-up wheel)

The motor drives the paper pick-up wheel to feed the copy paper into the machine to prepare for the next transfer of the toner image on the drum surface to the paper.

5. Transfer parts (high-voltage generator, electrode holder, motor wire)

The surface of the copy paper is charged with a uniform charge opposite to that of the toner through the transfer electrode, and the toner image on the photosensitive drum is transferred to the copy paper.

6. Separation parts (high-voltage generator, electrode holder, motor wire)

Because the surfaces of the copy paper and the photosensitive drum are charged with opposite polarities, the copy paper is not easy to be separated from the photosensitive drum during copying. Therefore, it is necessary to take separation measures to separate the copied copy paper from the drum smoothly. Earlier copiers used mechanical separation, but it was easy to jam; Current duplicators all adopt current separation. The separation current contains high frequency AC and fixed DC components.

7. Cleaning parts (cleaner)

Clean the residual toner on the surface of the photosensitive drum to prepare for the next copy. It is impossible for all copiers to completely transfer the toner on the surface of the photosensitive drum to the copy paper through transfer. Therefore, there is residual toner on the drum surface, which will affect the quality of copies in the future if it is not cleaned.

8. Fixing parts (fixing hot rod, pressure rod, heater)

The toner image on the copy paper is fixed on the copy paper by fixing, which is convenient for storage. If it is not fixed, the image on the copy paper will drop as soon as it touches. (So fixing requires a certain temperature and pressure)

Reference Baidu Encyclopedia-Copier