Just like we use a pen to write on paper, the scanning exposure tool uses a laser beam to "write" the exposure on the photosensitive drum. This text or image is invisible. This is what we call "electrostatic latent image." .
When the surface of the toner cartridge passes through the tungsten wire electrode, the surface is charged with positive electricity, and the interface between the photoconductive layer and the substrate induces negative electricity. When the light part of the laser beam hits a certain area on the drum surface, it is called exposure. The resistivity of the exposed area is significantly reduced, and the positive charge on the surface and the negative charge on the interface are neutralized and disappeared. Due to the good insulating properties between the selenium-tellurium alloy particles, the positive charge on the surface of the unexposed surface remains unchanged. That is, a layer of electrostatic latent image is formed.
Scanning exposure is to use the photosensitive properties of the photoconductive material on the surface of the photosensitive drum. When the photoconductor is scanned and irradiated by the laser beam, the illuminated part is connected to the conductive layer of the photosensitive drum so that the charge disappears, and the part not illuminated by the light still maintains the charged charge, thus forming a potential difference image, which can also be understood as The "discharge" process of the photosensitive drum. During the de-charge process, the potential on the surface of the photoconductor is changing, and this potential change has a great influence on the print quality.
When charging the surface of the photosensitive drum, as the charge accumulates on the surface of the photosensitive drum, the potential continues to rise, and finally reaches the "saturation" potential, which is the highest potential. The surface potential will decrease with the passage of time. Generally, the working potential is lower than this potential. This process of natural decrease in potential over time is called the "dark decay" process. When the photosensitive drum is scanned and exposed, the dark area (referring to the surface of the photoconductor not irradiated by light) is still in the dark decay process; the bright area (referring to the surface of the photoconductor of the part irradiated by light) the carrier density in the photoconductive layer increases rapidly. The electrical conductivity rises rapidly, forming a photoconductive voltage, the charge quickly disappears, and the surface potential of the photoconductor also drops rapidly, which is called "light decay", and finally slows down.
Theoretically speaking, the faster and more thorough the light decay, the better, but in practice it is difficult to achieve. The level of the remaining residual potential will affect the print quality. If the residual potential is too high, the phenomenon of "dust at the bottom of the print" will appear. After an electrostatic latent image is formed, it must undergo a "development" process as described below before it can be converted into a toner image.
[Disclaimer: The above content comes from the Internet, and does not represent the views of this site. I hope some of the content can help you. 】
We (Alice) are a manufacturer specializing in the production of nameplates for office appliances. We have 21 years of experience in making furniture signs. We can produce zinc alloy, aluminum alloy, stainless steel, copper, brass, iron, and titanium. , PC, PET, PE, pvc and other different labels.
Contact us E-mail: sales03@alicelogo.com
whatApp: +86 132 6564 6796