12/5/2023 0 Comments Photocopy vs xeroxIn older analog copiers, reflected light from an illuminated image is projected onto the photoreceptor. In a digital copier or printer, the image is exposed on the photoreceptor with a scanning modulated laser or a light-emitting-diode image bar. Ions of the same polarity as the voltage on the wires deposit on the photoreceptor's surface, creating an electric field across it. It is charged in the dark by applying a high DC voltage to adjacent wires, which produces an intense electric field near the wires that causes the air molecules to ionize. The photoreceptor is insulating in the dark, but becomes conducting when it is exposed to light. It consists of a thin layer of photoconductive material that is applied to a flexible belt or drum. Inside every copier and laser printer is a light-sensitive surface called a photoreceptor. Todays copiers and printers have automated and refined all the steps, moving paper at speeds of more than 250 feet a minute, digitally creating and exposing images, and producing images in a rainbow of colors. Finally, heat fuses the powder image to the paper, producing a copy of the original image.Ĭarlsons first image, produced on October 22, 1938, was created with negatively charged yellowish moss spores (lycopodium) on a sulfur-coated zinc plate that had been positively charged by rubbing it with a handkerchief. The negatively charged powder is attracted to the paper as it is separated from the photoconductor. A piece of paper is placed over the powder image and then given a positive charge. Negatively charged powder spread over the surface adheres through electrostatic attraction to the positively charged image areas. Because the illuminated sections (the non-image areas) become more conductive, the charge dissipates in the exposed areas. The photoconductive surface is then exposed to the image of a document. First, a photoconductive surface is given a positive electrical charge. Carlson invented a six-step process to transfer an image from one surface to another using these phenomena. Its based on two natural phenomena: that materials of opposite electrical charges attract and that some materials become better conductors of electricity when exposed to light. In addition, the xerographic process is actually used to make both copies and prints.Ĭarlson originally called the process electrophotography. Because Xerox marketed the first plain-paper copiers, photocopying machines made by other companies are sometimes referred to as "Xerox machines" by those who dont realize its a misuse of the companys trademark. The xerographic process, which was invented by Chester Carlson in 1938 and developed and commercialized by the Xerox Corporation, is widely used to produce high-quality text and graphic images on paper. Hays, a senior fellow at the Xerox Corporation's Wilson Center for Research and Technology, explains.
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |