In 1950, the first commercial dry copier, the Model A, came onto the market. However, it was not yet easy to use because the user had to carry out 39 steps to make a copy. In 1959, the first fully automatic copier came on the market: the Xerox 914, which at that time already made 6 copies per minute on plain paper. However, it was not possible to buy this copier, but only to rent it. The basic rent included 2,000 copies a month, each additional copy cost 4 cents.
The first printer, the so-called alphabet printer, was developed in 1953. The alphabet printer was a kind of electric typewriter that was connected to a computer. However, the alphabet printer was quickly superseded by the dot matrix printer. In dot-matrix printing, steel needles are first pressed against an ink ribbon and then onto the paper. Initially, the models used 9 needles for this, later 24. The first colour printers were also developed at this time. The dot matrix printers were eventually replaced by inkjet printers, which use liquid ink for printing, which is sprayed onto the paper through fine nozzles. With the use of coloured ink, printing images finally became possible and special paper enabled increasingly high print quality. Since the beginning of the 1980s, laser printers have been available, which were originally developed for large companies and have now become affordable for private use due to falling production costs. In laser printing, a laser beam writes the printed image onto an exposure drum (image drum). The toner adheres to the written areas, is transferred to the paper in the next step and is fixed by heating. Because laser printers are fast, cheap and quiet, they are often used in offices.
Printer (peripheral device)
A printer is an external peripheral device used in data processing. This means that the printer is a so-called accessory that is located outside the central unit of a computer and is connected to the computer by a cable or also by infrared or radio technology. The printer prints prepared digital characters and images on paper or other surfaces.
Distinguishing criteria for printers
Printers can be distinguished according to various criteria: with or without media contact, according to the smallest printable unit, according to the printer interface or the printing method.
With regard to the printer interface, one can distinguish between wired (parallel, USB, Ethernet) or wireless (Bluetooth, IrDA, WLAN). According to the criterion of the smallest printable unit, a distinction is made between character, line and page printers. These would be, for example, type wheel, type chain and laser printers. Character printers can be divided into bidirectional and unidirectional printers. In bidirectional printers (all modern dot matrix and inkjet printers), the print head can print in both directions as it moves back and forth. Compared to unidirectional printers, bidirectional printers consequently save time because printing can also be done when the print head is moving backwards.
According to the printing method, the most important printers are classified as ball-head printers, type wheel printers, laser printers, colour laser printers, LCD/LCS printers, dot matrix printers, line printers, inkjet printers, metal printers (electro-erosion printers), thermal printers, thermal transfer printers, colour printers, label printers, wax printers and dye sublimation printers.
Printers with media contact, so-called impact printers, include the type wheel printer, the (type) teleprinter, the ball-head printer, the cylinder-head printer, the dot-matrix printer, the dot-matrix printer, drum or roller printers and the belt or chain printer. An impact printer is a printer that uses an ink ribbon to print the document to be printed onto the paper. Non-impact printers, i.e. printers that do not touch the media, include inkjet printers, laser printers, thermal printers, thermal transfer printers and dye sublimation printers. Non-impact printing (NIP) processes are electronic printing processes without an explicit printing form.
The ball-head printer works on the principle of the ball-head typewriter and belongs to the group of impact printers. With the ball-head printer, a round print head moves. Because the whole wheel does not have to be turned again and again like with the type wheel printer in order to get to the next character, the ball-head printer achieves a higher speed than its predecessor. The ball head rotates quickly and, when the correct stamp is in front of the paper, presses down on an ink ribbon. This ribbon then prints ink onto the paper behind it. However, this printing method was replaced some time ago by laser printers and inkjet printers.
Drum printers, also called type drum or roller printers, belong to the group of line and impact printers. On the so-called type drum, the most important component of a drum printer, there is a disc with all the printable characters for each printing position. This type drum is rotated until the desired letter to be printed appears. However, since the type drum is too heavy to be used for striking the letters, the drum remains in position and small hammers strike the printing material and the ink ribbon on the roller. There is one hammer for each printing position. However, since no complete line is to be printed with the same character, a line is only finished when the drum has rotated once completely and thus every character was present at every printing position. Drum printers can reach speeds of several hundred lines per minute.
A chain printer was used in the computer sector in the 70s and 80s, but is now an obsolete printing device. With a chain printer, a fast rotating chain with applied print types is fed over an ink ribbon. The ribbon is usually in the form of an ink cloth to cope with the high mechanical stresses. At each printing position there is a hammer mechanism controlled by an electromagnet. The individual hammers strike exactly when the desired character of the type chain passes the printing position. The printout is made on continuous paper. The printing speed of a chain printer was very high even in the early days. At that time, devices were in operation that could print pages every second. The high speed is achieved by the fact that some of the printable characters are present several times on the type ribbon, so that the characters to be printed in a line can not only be printed sequentially, but also simultaneously within certain limits. This also shows why chain printers are also called line printers. The number of copies that can be used is also very high, which is why many chain printers are still used today for mass printing, especially in the logistics sector.
Character, line and page printers
Character printers are printers that print letters completely and consecutively on paper. The group of character printers includes the type wheel printer and the ball-head printer. A disadvantage of the character printer method is that the character set cannot be changed and graphic output is not possible at all. In most applications, character printers have been replaced by matrix printers or page printers.
Line printers are high-speed printers that put a line on paper in one go rather than sequentially. There are different types of line printers, but what they all have in common is that many types print more or less simultaneously on different columns of a line. Between them is either an ink ribbon or an ink cloth. Line printers are still in use today for bulk jobs, especially when carbon copies are required. One disadvantage of line printers is the high level of noise, which is why line printers are usually set up in separate rooms or with soundproof bonnets. In the 1960s to 1980s, line printers were used as peripheral devices on mainframe computers. In smaller companies with high print volumes, matrix printers were also used, which were equipped with a needle comb across the entire line width instead of a movable print head. Some of these printers even had graphics capability, could print different character sets and could handle important font attributes. Later, line printers were replaced by modern laser printers which, in contrast to line printers, can print an entire page in one operation with both text and lines and graphics and also work much more quietly. However, it is not possible to print carbon copies with laser printers, which is why so-called multiple originals are used. Today, more advanced representatives of the mechanical line printer, such as the drum printer and the chain printer, are used.
With a page printer, such as the laser printer, the characters to be printed are transferred as a whole onto a page. With laser printing, the printed page is first prepared and then the printed image is transferred from the image drum to the paper in one pass. For this process, a relatively large memory must be available in the laser printer to accommodate the data of a page. For laser printers, the minimum is 512 kilobytes, depending on the print resolution. If graphic pages are to be printed, the memory must be correspondingly larger.