1843, American physicist Alexander Bess invented the fax machine according to the pendulum principle. 1850, christopher baker Weil in the United States began to replace Alexander Bain's pendulum mode with "roller and screw" device, which made fax technology take a step forward. 1865, Iranian Abakatri made a practical fax machine according to the principle put forward by Bain and Bakewell, and conducted fax communication experiments among French cities such as Paris, Lyon and Marseille. It can be seen that fax has a history of 150 years since its invention, but its popularity has been in recent decades. Prior to this, its development was very slow, mainly limited by the use conditions and backward technology. Since 1970s, countries all over the world have opened fax services on the public switched telephone network, and fax has been widely developed. Especially in 1980s, with the progress of fax machine standardization and the maturity of technology, it became the fastest developing non-voice service. To sum up, fax has gone through the following three stages from production to development;
(1) basic stage (1843— 1972)
1906, German physicist Arthur Kern developed the first optical fax machine. He used a sensitive ammeter to control the photoelectric switch at the receiving end, thus changing the luminous flux shining on the photosensitive paper.
In 1930s, the fax machine was finally put into use after many improvements. At that time, its main users were major newspapers.
From 65438 to 0974, with the improvement of people's demand for information and the development of electronic technology, Americans developed the world's first electronic fax machine. Its characteristic is to apply the concept of modulation and demodulation to line transmission, thus making a qualitative leap in speed and clarity.
However, it was Japan that promoted the widespread use of fax machines. It is difficult for Japanese pseudonyms and Chinese characters to be transmitted quickly by telegraph, so the Japanese have invested a lot of energy in developing fax machines that can transmit information at high speed.
In the 1990s, the transmission speed and clarity of fax machines were constantly improved, and the print media began to diversify. Ribbon fax machines, inkjet fax machines and laser fax machines appear, and finally enter the office and even the home.
At present, fax machines basically adopt mechanical scanning mode, and most of them adopt roller scanning. The circuit of fax machine adopts analog technology and discrete components. In terms of transmission, low-efficiency modulation technologies such as amplitude modulation and frequency modulation are adopted, and low-speed transmission is basically carried out by using special wired circuits. At this time, the application scope of fax is also very narrow, mainly used for news and weather broadcast.
(2) Development and promotion stage (1972-1980)
Since 1969, especially after 1972, fax has entered a new historical development period compared with ITT's progress in fax standardization and the development of fax technology itself. During this period, fax technology developed from analog to digital, mechanical scanning was replaced by solid-state electronic scanning, and low-speed transmission developed to high-speed transmission. Represented by document fax machine, its appearance and popularity have changed people's traditional views on fax machines and accelerated the development of fax communication. In addition, the application scope of fax has also expanded. In addition to transmitting documents, news photos and weather maps, it is also used in medical treatment, printing, book management, information consultation, financial data, electronic post and so on.
(3) Multifunctional Stage (after 1980)
At present, fax machine is not only widely used as communication equipment, but also plays an important role in office automation system and e-mail, and will transition to a comprehensive processing terminal. After 2 1 century, it began to combine with microcomputers, using computer technology to increase the functions of fax in information collection, storage, processing and exchange, and gradually incorporated it into the integrated services digital network (ISDN).