Category: Science and Engineering gt; gt; Engineering Technology Science
Question description:
The name of the question and its principle
Analysis :
Development of xerographic copying technology:
1. Carlson invented the When using salt photography as a direct photocopying method, Carlson combined the two ideas of using a photoconductive medium to discharge electricity to form an electrostatic latent image, and electrostatically charged powder to develop the latent image. With the same idea, he successfully researched a method to form an electrostatic latent image on a photoconductive insulating film layer, which led him to invent the electrostatic copying technology. In October 1938, with the help of Otto Kornei, he obtained the patent for the first copying machine; in 1939, Carlson also successfully manufactured a model of a copying device. It was not until September 1959 that the American Xerox Company built the world's first floor-standing office Xerox 914 fully automatic copier, which opened a new page in the history of the world's office copiers.
2. Analog electrostatic copier
In the 30 years from the 1960s to the 1980s, the development of electrostatic copying technology has advanced by leaps and bounds, changing with each passing day. In the past 30 years, the research on copy technology in the first 20 years mainly focused on photoconductor technology. IBM has studied technologies in single-component developing systems and organic photoconductors. From 1970 to 1972, two types of copiers were developed. They used organic photoconductors coated on lead foil to replace amorphous selenium. The organic photoconductors were then made into long strips and wound around the drum, which improved the efficiency of the photoconductors. service life. RCA Corporation studied another copying method called the direct method. In this method, the photoconductor is used as a coating on the paper, and zinc oxide (ZnO) photosensitive material is mixed with an adhesive, and then thinly coated on the paper as photosensitive copy paper. For example: the Xerox 813 electrostatic copier, as well as the 1400 and 3600 copiers made by Xerox in the United States from 1963 to 1964; in 1965, the Japanese Ricoh Company successfully developed an electrostatic photoconductor using cadmium sulfide as a photoconductive material and an insulating film surface; Japan Konishi-Roku Company and Océ Company have successfully developed photoconductors made of zinc oxide. Selenium, cadmium sulfide, zinc oxide, and organic photoconductors (OPC) currently used were all successfully developed during this period. During the 1970-1980 period, Japan made important developments in xerography technology. During this period, Japan's Ricoh Company produced a copier with a liquid developing system. Its liquid developing system saves developers, reduces technical costs, and improves machine reliability. The Japanese company Canon also made many important new discoveries. First, a new photoconductor is developed. The photoconductor is composed of two layers of films. The upper layer is an insulating layer and the lower layer is a cadmium sulfide photoreceptor film layer. Exposure and charging are performed at the same time, thereby producing an electrostatic latent image, and the charge of the latent image is retained. at the interface between two films. They call it the "New Process" or "NP" method for short. In 1970, Canon launched the NP-type copier to the market. In 1980, the NP-200 desktop copier, the first single-component developing system using insulating magnetic toner, was launched. This development system eliminates the carrier used in the waterfall development system and the magnetic brush development system, and is suitable for the real ordinary paper copying process. Its small size is also conducive to the design of small and cheap desktop copiers.