Printer

Characteristics

It is important to consider the following characteristics in the choice of a printer:

print speed: the number of pages printed per minute; for the color printers, the number of pages printed per minute can vary according to whether the impression is done in black and white or color;
the resolution: precision of the impression; the precision is measured in points per inch (PPP or dpi for dowry per inch in English); for the color printers, the resolution can vary according to whether the impression is done in black and white or color;
the time of pre-heating: warming-up time of the printer before the beginning of the impression;
memory of the printer: it on standby measures the quantity of information of impression which the printer can preserve in its memory;
the paper format: maximum size of the sheets which the printer can accept;
the type of food of the blank paper: the two principal types of food are:

food by vat or drawer which uses an invessel fuel storage of a great number of sheets of paper,
food by plate which uses an outvessel fuel storage of an minor amount of sheets (from 50 to 100);

cartridges: they are seldom standard; to see the ways of saving on the cost of the cartridges in the section Sales strategy ;
the interface: connection series, parallel Port, USB, Wifi, Ethernet/IPv4 (example HP Deskjet 6840), Ethernet IPv6;
of other physical characteristics like dimension, the weight and the noise level can also be important in certain cases.

Mode of impression

Recto-Back mode (or duplex)

The recto-back mode, also called duplex mode, makes it possible to print on the two sides of a sheet. Designation " simplex" mode; is sometimes used to print on one only face. There exists manual the recto-back mode and the automatic recto-back mode. The manual mode consists in repositioning the paper in the way indicated to print on the second side. The automatic mode does not need any handling but depends on the capacities on the printer, it is thus not valid on all the printers. There exist also the denominations Tumble and NoTumble, they correspond respectively, to print in recto-back so as to obtain a reading while turning the pages like a scratch pad, and as a normal book.

Booklet mode

It makes it possible to print in recto-back and so that each side of a sheet contains two pages. (An illustration would be the welcome)

Sales strategy

Currently, the printers general public are sold at a close price, even lower, with that of the cartridges. The profit margin is thus made on the cartridges. For fidéliser (or to connect) the customers, all the printers use different cartridges (absence of standard).

There exist two ways of thwarting this strategy and of reducing its costs of impression:

As it is the case in the Drug company with the generic medicines, it is possible to get compatible cartridges with approximately 50% of the price of the cartridges of origin. However, certain printers are equipped with an electronic device blocking the printer in the event of detection of cartridge not coming from the manufacturer of origin.
For those which are patient and a little handymen, it is possible to fill of ink some cartridges and to thus carry out a saving in approximately 80% compared to the price of a cartouche coming from the manufacturer.

A die of recycling of the cartridges of worn printers is set up. It is possible to collect its worn cartridges via associations or specialized companies…

Technologies of impression

The printers are generally classified in two distinct categories according to whether they use a mechanical striking or not (printing impact) (printing not-impact or NIP).

Printer Impact

Hammer printer or Chain printer

Used especially on the large host computers, their mechanism of impression consisted of a chain on which all the printable characters were fixed. This chain, pulled by two axes - a such chain of bicycle - was constantly moving fast above the line to be printed. Along the course of the chain were laid out of the hammers (as much as number of characters per line - for example 132). In the passing of the character to be printed, the hammer of the column concerned struck it to print it the page. This system of impression was rather fast (there existed printers besides which contained a whole series of chains the ones below the others, which made it possible to print a whole page of only one blow). But the character set was limited, and of course, there was no question of changing police force quickly, or of printing graphs. In addition these printers were extremely noisy.

Wire-matrix printer or Dot-matrix printer

On the wire-matrix printers, the print head consists of a series of needles, rows vertically in order to cover the height of a line of text and propelled by electromagnet S. the number of needles can vary from one printer to another (from 9 to 32 in general), the quality of impression is proportional to the number of needles. This head moves along the line to print.

Ink is provided by an inking ribbon, similar to the ribbons of typewriters (impregnated fabric of ink), which circulates in loop between the print head and the sheet of paper. Each needle makes it possible to print a tiny point on the sheet; each character thus consists of multiple points.

This technology makes it possible to print on carbon-interleaved sets making it possible to have an immediate double of the document. It thus remains used for this purpose in certain companies.

Wheel printer or Daisywheel printer

Inspired by the typewriters, the print head consists of a rosette, at the periphery of which the various printable characters are fixed, the such petals of a daisy… This rosette turns on a motorized axis. The system moves along the line to print.

For each character to be printed, the rosette carries out a rotation to present the character required in front of a hammer, which striking character on the page, through a Inking ribbon. This system is rather slow and presents only one restricted character set. It is however possible to change the police force into changing the daisy.

An alternative, created originally by IBM, comprises a Sphère in the place of the daisy.

Printer with tulip

Derived from the daisywheel printer, the printer with tulip uses a wheel of which " pétales" would have been folded with 90°. It follows a greater compactness of the unit and the possibility of putting 2 characters at the end of each petal (only one on a daisy), the passage of the one with the other of the characters of the same petal being done by rise and descent of the print head. Compared to the daisy, the impression with a tulip is faster and the number of characters per wheel is more important. As for the daisy, it is possible to replace the tulip in the event of breakage or simply to change typestyle.

This system marks the end of the evolution of the printers impact which will be supplanted starting from the Années 1990 by the arrival of the printers not-impact.

Printer Not-Impact

Printer with thermal head

Direct thermics (economic)

This mode of impression requires a sensitized paper to heat. The text and the graphs are transferred on the paper which moves in front of a line (the width of paper) tiny heating electrical resistances. This process presents several disadvantages:

need for using a specific paper and rather expensive
a bad conservation. Exposed to heat (for example: the sun behind a pane), paper blackens just as there remains sensitive to the stripe, but even safe from heat after several months paper yellows and the impressions disappear.

A contrario, the fact of not using a tank of ink or film of inking makes that the system is simple to implement. This type of impression is very present in the Télécopieur S but also on the automatic teller machines, the balances of the supermarkets, the computerized Billetterie, etc

Heat transfer (high-quality)

As for direct thermics, one finds a print head made up of a series of small heating resistances. Here, it is not a special paper which is used but a film of inking sensitive to heat. At the time of the impression ink passes completely on the support and the ribbon is thus usable only once (see however the ticket application which used a multipass special ribbon). The film of impression is usually black but can be declined in a multitude of colors. There exist even two-tone ribbons (impression in red and black) and a technique, from now on abandoned, used tri ribbons or quadrichromy.

The range of the printable supports is large since one can print on papers chechmates or brilliances, films of packing, textiles, etc

The various applications are the following ones:

Labelling - impression of texts, logos, code-bars)
(print over packaging) - packing. In this case the impression can be done in two times, a first transfer on a special film then a second on the object in question (if the first transfer is done flat, the object can present a relief, the second impression coming to marry the forms of this one).
Ticket - the impression of tickets of loading (railway, air) used cassettes with ribbon heat transfer known as multipass with which it was possible to print up to 6 or 7 times at the same place, lowering of this fact the cost of the impression but it to the detriment of quality (less important criterion for this type of use).
Fax - certain telecopiers use an impression of the heat transfer type what allows obtaining documents being able to be filed (what is not the case with direct thermics).

Except for the impressions of tickets, this type of impression is of great quality, at the price of a rather high cost price and a rather low speed, but a great silence. It is reserved for industrial applications and is not proposed with the general public except for some telecopiers.

Printer with sublimation

principal Article: Printing with sublimation

In this technology, the ink, heated by a system similar to printing the heat transfer, is sublimated (passes from the solid state in a gas state). In contact with the support to be printed a condensation takes place. The large advantage of these printers is obtaining points more or less coloured according to the temperature of heating, in addition it is possible to mix on the same zone several primary colors to thus obtain a pixel in a secondary color (contrary to other technologies where there is right juxtaposition of the colors). This asset made Imprimante with sublimation a must for the photographic impression of high-quality. However its prohibitory cost made it inaccessible to the general public.

Laser writer

principal Article: Laser writer

On this system, ink is appeared as an extremely fine powder, the Toner. During the impression, a laser draws on a rotary photosensitive drum the page to be printed, a polarizing electric device makes a magnetic spectrum of it . On this drum, powder ink polarized conversely then comes to be distributed, adhering only to the zones marked by the laser. A virgin sheet, passes between the drum and a grid it even electrically charged, is applied to the drum ink, recovering ink. The fixing of ink on the sheet is done then by heating and compression of the sheet encrée in a thermal furnace.

This technique, although sophisticated, allows a fast impression (either line by line, but page by page) very fine and very flexible (impression of all types of texts, graphics, photographs…) with an irreproachable quality for the black and white. However, it is adapted little to the levels of gray, and so to color printing. The technological changes and of the techniques of the beginning of the 21e century made it possible to adapt the color to this system of impression.

The laser writer makes it possible to obtain pullings paper of quality, with low costs and with a print speed high. On the other hand, the cost of acquisition of such a printer mainly intends it for semi uses professional or professional.

This technology of impression is directly derived from that used formerly in the Photocopieur S. With that close before, it is reflected light by the page to be duplicated which discharged the drum. Nowadays, the great majority of the photocopiers are in fact laser of the surmounted printers of a scanner and are used like printer.

Formerly from ozone released itself in quantity during the impression. In question the system which charges paper electrically. In the beginning, it was a " corona" , discussion thread under tension high placed remotely sheet of paper. Corona made react oxygen by transforming it into ozone. The printers were then equipped with a filter traps with ozone, always not replaced, not affecting the quality of the impressions. This defect of maintenance could pose problem in the badly ventilated buildings especially, ozone accumulating there. The current printers do not produce almost any more ozone. Indeed as from 1992, corona was replaced by a flexible and conducting roller named roller of transfer, directly in contact with paper.

Printers laser color

One distinguishes in fact two technologies for the printers laser colors: " carousel" (four passages) or " tandem" (monopasse).

carousel: With technology carousel, the printer carries out four passages to print a document (one by primary color and for the black, with the result that the impression is in theory four times slower color than in black).
tandem: A laser writer exploiting technology “tandem” deposits each color in only one passage, the toners being laid out in parallel. The exits are as fast in black as color. This technology has however a cost price more raised, mechanics being more complex. It was thus, until it, held little there in theory for the printers laser color of medium or high-end. Since 2005, more and more of marks propose models “tandem” as of the line entry.

The majority of the models print their serial number in the form of invisible points systematically coloured with the naked eye and thus making it possible to find the origin of a reproduction.

Printer with LED

principal Article: Printing with LED

Of a technology similar to the printers laser, the printers with LED (Diodes Electroluminescent or English LED), used a bar of LED to insolate the photosensitive drum. Compared to the printers laser, the cost of implementation was weaker, a contrario, the smoothness did not exceed the 300 points per inch (dpi) what, in the long term, made that this technology was given up by the majority of the marks (the printers laser reach from now on the 1200 dpi, movement followed since by the marks still producing printers with LED).

Ink jet printer of ink

principal Article: Ink jet printer of ink

The print heads jet of ink use liquid ink contained in a tank known as Toner. The head itself is bored fine channels filled with ink, and a piezoelectric system or of electric heating produces variations of pressure which expel droplets on the sheet, formant of the points.

As with the heads with needles, the characters are formed by concentrations of points, and the impression is thus made line by line. Nevertheless, the smoothness of these droplets is controllable, and technology allows a mixture of the colors, so that the majority of the printers recent jet of ink impressions “Qualité photo allows”.

Magnétographique printer

These printers use magnetic black ink. They print only in black and white. Information is recorded on a magnetic drum (a large metal cylinder). Each point is placed magnetically on the drum thanks to write heads. At this stage, there is nothing on the substrate. Then, ink with magnetic particle is attracted on the substrate by the drum. The substrate thus passes near the drum and from thundering. Then, ink is fixed at the substrate by a flash which melts it with 50°C. Ink is definitively fixed on the substrate.

The advantage of this mode of impression is the diversity of the substrates usable. These printers print on paper (lying or not), plastic, plasticized paperboard, and they can also print on several layers of paper, without using the traditional technique of carbon. A chemical substance makes it possible to defer the reason for impression on sub-bases.

The quality of impression can go up until 600dpi. Speed can reach 125 m/min. Knowing that more than 70% of the surface of the cylinder can be changed with each passage, these printers are the ultimate tool to print books, invoices, and all other documents whose pages are not identical.

With an adapted system, two machines can print recto-back, one following the other. One can then reach the 250 m/min.

Methods of traction of paper

Paper was guided a long time in the printer by what one called the caroles - a punched paper tape of large regular holes which ran on the right and on the left of the sheet. Toothed wheels came to be encased in these holes to advance or move back paper all while maintaining it well in the axis of the impression.
This band was precut, to be more easily detached after the impression. The disadvantages of this solution are:

obligation to use special paper (continuous paper, in which the sheets and the caroles are precut);
the framing of paper was often delicate.

A contrario, one obtained a bundle of several pages of only one holding. Nevertheless that had truly direction only for the professionals and was without interest for the general public.

Since the appearance of the first laser printers, paper with caroles gradually disappeared: the traction of paper is done henceforth by rollers which enclose and guide paper throughout its way in the printer. Nevertheless, if this method allows the use of normal paper, it always does not guarantee a perfect framing of paper, and is more prone to the stuffings .

Language of impression

Each printer uses a language to make it possible the computer to communicate with it. The wire-matrix printers a long time used a language actually coding a succession of Pixel S binary on a rectangular matrix 8×8 or 8×16. During Years 1970, the company Hewlett-Packard developed a structured interpreted language in orders, the Hewlett-Packard Graphics Language , or HP-GL. With this language, a file drawing was for the first time a formatted file (and either binary), that an informed user could modify with an editor, without passing by a programme of drawing or a graphic language with a specific pilot.

This language was still used for the first printers laser of this manufacturer at the end of the Années 1980 (what proves the coherence and the relevance of its initial design), but was quickly improved as from this moment (1989), taking into account the emergence (and soon of the quasi-supremacy) of PostScript: this improvement led to HP-GL II. This last language comprised the possibility, like its rival of Adobe Systems, to create Sous-programme S, and integrated the Algorithme of the painter for the Détermination of hidden surfaces, but it was attached in terms of evolution because too related to a manufacturer. In particular, it integrated only the police forces available on the Hewlett-Packard printers.

It is to break this limitation that Hewlett-Packard created the language PCL 5, today most frequently used.

The PostScript language of the company Adobe (1987) had been from the start adapted to the possibilities of the printers laser, and, though language owner until 1992, it was essential during these years like the standard which it became since.

Manufacturers of printers

Dell
Brother
Canon
Epson
Fargo Electronics
Hewlett Packard
IBM
Kyocera
Lexmark
Minolta
Nipson
OCE
Oki
Olivetti
Ricoh
Samsung
Toshiba
Xerox

References

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