The present invention relates to a printer techno¬ logy particularly aiming at graphical industries, in which it is actual to operate e.g. with more different printer types for different kinds of work. The term ^■ •printer" is an accepted technical designation for printing units, which, aided by computer controlled electronic control means, can be operated for instant activation/passivation while the medium to be printed is moved past the printer, such that the print picture can be built up with a desired high degree of resolution without the use of physical printing masters as in printing presses, for example.

Inasfar as "printers" are commonly thought of as being office equipment for printing of usual paper sheets or even for the printing of drawings as large as size A ₀ , it should be emphasized that the invention is predominantly related to specialized industrial equip¬ ment for working of considerably still larger surfaces, e.g. 2x3 m. Moreover, it is relevant to consider the preparation of serigraphical printing frames, which may be actual for the production of more than e.g. 10-15 impressions, while a lower number of impressions may better be prepared by some other technique.

Various basic technologies for the operation of the printer units have been developed, based e.g. on elec¬ trostatic charging and a following take-up of a toner or on the so-called ink-jet principle, where the printer unit effects a controlled, direct spraying on of the ink. It is possible to make plural colour prints by the use of more printer units arranged in a row.

It has been found that for the graphical enterpri¬ ses it is highly advantageous to have at disposal prin¬ ters based on several of the relevant technologies, each of these having special advantages/disadvantages that

make them particularly well suited or unsuited for dif¬ ferent print carriers such as paper or paperboard, vinyl sheets and other sheets ; even exposure units for laser irradiation of a photographic emulsion on serigraphical printing frames should be considered.

It has been and will still be a natural development that different manufacturers of printer units specialize on certain printing technologies, and just as in the market for office machines such as printers and photo¬ copiers it is correspondingly natural that the manufac¬ turers develop and deliver complete machine units, each usable for printing production based on the specific technology.

According to the invention, however, it has been recognized that it is advantageously possible to split up the machine production to the effect that a standard equipment be produced for exersizing the basic or common functions of the different machine units, viz. the rela¬ tive motion between the very printing unit and the media to be printed, as well as the controlling of this moti¬ on, irrespectively of the printing technology used. What will be left is that such an equipment should be selec¬ tively suppliable with printing units of different types. In connection with the invention it has been found that the different printing units are rather uni¬ form with respect to space requirements, such that they may well be adapted, physically, to be coupled with a standardized carrier device in a common machine frame.

Roughly, the machine construction of the printer apparatuses amounts to some 3/4 of their production price, and in the single enterprises long periods of time may occur, in which a certain type of printer is not used at all, i.e. in which this special printer with its required, relatively high capacity, is just passive. With the system of the invention it will be possible to freely combine e.g. 3-4 different sets of printing units

with e.g. two standard machines, whereby these may ope¬ rate with a generally increased capacity or, respective¬ ly, with a noticeably lower investment for a given total capacity.

The common control not only applies to the mechani¬ cal control, but largely also to the associated computer control of the movements, i.e. the superior control unit. For the latter it it without significance, in principle, whether the printing unit functions according to one or another technology, and particularly for this reason it is highly relevant that one same control equipment can be used for the practicing of the diffe¬ rent techniques.

Noticeable advantages will be obtained also in the operational practice, as it is possible not only to change technology, but also e.g. ink colour with un¬ changed technology. A set of printing units may be cleaned while the production continues with another set, which increases the capacity. There is a current devel¬ opment in the different printing technologies, and new technologies appear. As far as it can be estimated, the chances will be favourable for any new solution to be adaptable for use in a system according to the inventi¬ on, whereby the major part of a procured printer can be considered long-insured in addition to being multi ap¬ plicable.

The basic equipment should be so adapted that it is able to effect transport at the higher of the velocities of the relevant techniques - and preferably still high¬ er, in anticipation of new and still faster techniques. Then, the basic equipment can be used over the entire range, from production jobs with relatively high copy numbers to preparation of printing masters for off-set, flexo and serigraphical printing.

In the following the invention is described i more detail with reference to the drawing, in which:

Fig. 1 is a perspective view of a first embodiment of a printer apparatus or system according to the inven¬ tion, and

Fig. 2 is a similar view of another embodiment.

In Fig. 1 is shown a printer cabinet 2 which, as a basic device, is without printing units, whilst other¬ wise having all equipment required for the transport of the web material 4 to be printed, just as it is prepared with various connector jacks for printing units 6 to be mounted in this device, such that these units can be connected to an associated control computer.

The mounted units 6 may be electrostatically ope¬ rating printing heads capable of working at relatively high speed, e.g. with a capacity of some 800 m ² /h for a web width of 150 cm.

According to the invention, however, it is possible to mount in the same basic device 2 other printing units 8 based on other technologies, e.g. of the types ink- jet, ion-print, dye-sublimation or light, the latter ranging over all light types, from infrared to ultra violet. It will ne natural that the different types of units be produced by respective, specialized manufac¬ turers and just be adapted to fit in the device 2, if necessary with the use of special adaptors.

Usually it will be desirable that the basic device 2 can hold four printing units for making four colour prints, but situations may occur where more or fewer units are needed, and besides it will also be possible to place directly in the device 2 one or more after treating units, e.g. a lacquering unit and a drying unit, so this is the reason for the indicated available space in the device 2. For that sake, the device can be used with but a single printing unit, be it for printing in one colour only or because the unit itself may print in more colours.

Fig. 2 shows a printer apparatus for large sheets.

including serigraphical frames. In a known manner the apparatus has a mounting plane for a possibly frame or plate carried printing sheet 10, which in case of paper or foil will be fixed by suction through the support, and guiding rails 12 for a traverse 14, on which there is displaceably mounted a sledge 16 containing a print¬ ing or irradiating head. This head may then be control¬ led to sweep over the entire working area by a two di¬ mensional movement.

As mentioned, that kind of apparatuses is known in different constructions based on different operation technologies, but according to the invention it is pos¬ sible to use one same mechanical construction irrespec¬ tively of the technology, such that the latter may easi¬ ly be adapted to different kinds of work, viz. in that the sledge 16 is provided as a standard carrier unit for the very heart unit of the various systems. In Fig. 2 this is marked only by the presence of a removable cover 18 on the sledge 16, by which it is possible to change out the printing head itself.

In Fig 2 it is additionally indicated that the basic apparatus can be alternatively used with the tra¬ verse 14 carrying a housing 20 for one or more printing units of the type shown in Fig. 1, i.e. units which should only move in one direction relative the working surface.

A further possibility, of course, will be that the respective parts 14,16 and 14,20 may be mounted in a stationary manner, while the sheet 10 to be printed is moved by suitable moving means. The system may be orien¬ ted in the space as desired, also horizontally.

Particularly in the preparation of serigraphical printing webs by exposure of a photographic emulsion thereon, the invention will provide for the marked ad¬ vantage that prior to the work being effected by means of an irradiation unit in the box 16 or the housing 20

it will be possible to obtain a transcript of the work¬ ing result, viz. by first running the control program with the use of a paper medium and a printing unit suit¬ able therefor. Upon examination of the printing result and consequentially needed adjustments, if any, of the control program, the operator may shift to a serigraphi¬ cal frame and an exposure unit, respectively. What is obtained is an absolutely reliable proof, being created based on control signals which are the same as will thereafter be used for the exposure, viz. by repetition from the same program source and moving mechanism.

Optionally it is possible to place in the printing unit holder both an irradiating unit and a printing unit, such that these units will not need to be changed out between the said operations. For the proof it will be insignificant whether the two units work in areas slightly staggered from each other.

Moreover, the possibility exists that almost until the last moment a decision can be made as to the produc¬ tion technique to be used, e.g. dependent of a late message as to the number of copies pertaining to an already programmed order. By way of example, a provisio¬ nal order for 200 copies may have been planned for seri- graphic production, while, if the order is reduced to 50 copies, a suitable printing technique may be more suit¬ able, even when associated with a slower production in case of a high degree of resolution.

It may be desirable, in connection with the tech¬ nique according to Fig. 2, to work at both sides of the medium sheet, e.g. by a modulated printing with ink-jet on one side concurrently with an exposing UV irradiation on the other side; in that case the two kinds of working should not even be in synchronism.