LaserPrinter as an Application of Electromagnetic Fields
LaserPrinter as an Application of Electromagnetic Fields
Abstract
The laser printer was an advanced version of xerographic copier, and it was invented in the year 1969. Laser printer applies the process of electrostatic digital printing to produce high quality print materials that may not be achieved with alternative technologies. Laser, which is a device with the capacity to emit electromagnetic radiation, is the main component of the printer. Printing is achieved when the drum that is negatively charged picks powdered ink that is electrically charged, which is then transferred to a sheet of paper to form an image. Laser printer differs from xerographic printers in that it produces the printed material through a direct scanning of a given medium across photoreceptors.
Key words: Photoreceptors, xerographic copiers, laser, photoreceptor.
The laser printer was developed in the year 1969 by Gary Starkweather, but it has been improved over the years to make it more effective. Starkweather developed the first prototype by modifying xerographic copier that was being used in the mid twentieth century [1]. It was named laser printer because it relies on the device known as laser to do the printing work. A laser is a device that emits electromagnetic radiation in a process known as optical amplification [1]. The release of radiations is attributed to emission of photons. The laser light that is emitted by the laser gadget has a high degree of temporal as well as spatial coherence, which cannot be obtained from other types of technology.
Fig. 1 Image of a laser device
How the laser printer works
Image processing and charging
An image encoded in a description language is converted into bitmap by the raster processor. The bitmap is stored in the raster memory. The primary roller then projects some electrostatic charge to a conducting unit known as the photoreceptor [2]. The photoreceptor is capable of storing charge on its external surface. An alternate current is applied to the primary roller in order to remove residual charges that might be left of the previously printed image. This AC runs parallel to the electromagnetic field created by electrostatic charge [3]. The roller then applies the direct current in order to establish a negative uniform current potential. The amorphous silicon layer is used to receive the light while a boron nitride layer is used as a barrier to prevent charge leakage. The opposite electrical fields tend to cling together because they attract each other [1].
Fig. 2 Laser printer drum and toner
Exposure and development
The laser beam plays the role of neutralizing the charge on the drum’s surface, which leaves a static electric image that is negatively charged. The surface of the drum with the image is then exposed to a toner. Toner particles acquire a negative charge and they are attracted electrostatically as they get into a developer drum. Toner particles repel with sections of the drug where negative charge remained since both of them are negative. Toner particles are attracted to the paper that is being passed under a photoreceptor. The printed paper also passes through the roller located at the fuse assembly at 200 0C in order to establish a permanent bond between the plastic ink and the paper.
Conclusion
The laser printer is among the greatest inventions that were made in the 20th century. It refers to an electrostatic digital printer that can produce a high quality graphics and texts. This is accomplished by passing a set of laser beam over a cylinder that is negatively charged. The effectiveness of a laser printer can be attributed to the fact that the laser device has the capacity to produce light with a high degree of temporal and spatial coherence, which is not difficult to get when using other types of technology.
References
[1]. Makhkamov, S. (2015). Laser printer. Course Work. Retrieved May 16, 2016, from http://phycomp.technion.ac.il/~project-11/laserprinter.pdf
[2]. Woodford, C. (2015, August 26). Laser printers. Explain that Staff. Retrieved May 16, 2016, from http://www.explainthatstuff.com/laserprinters.html
[3]. Andres, J. (2009). A+ guide to managing and maintaining your PC. Boston: Cengage Learning