EP0615844A1 - Modular ink jet print head - Google Patents

Abstract

A modular ink jet print head has modules (1) with three spacers (20) on their periphery in order to maintain a constant spacing b between the modules (1). The latter are attached to the module part by their base surface (34) standing upright on a reference plane. The spacers of the one module are brought into contact with at least those of one further module. A base plate (36) and two limbs (38) arranged on two first sides of the base plate (36) form a U-shaped module carrier (10). For the modules, fastening elements (23, 24, 25, 26) are arranged on the two second sides of the base plate (36) and adjusting means (27, 28) are arranged on the limbs (38). On one side - located parallel to one of the second sides of the base plate, offset stop edges (29) for all the modules (1) are worked into the common opening (37) of the base plate (36) for the leading edges of all the modules (1). The reference edge (21) of each module (1) is brought into contact with an assigned stop edge (29) on the base plate (36), thus resulting in a defined lateral offset c between the modules (1). <IMAGE>

Description

The invention relates to a modular ink jet print head of the type specified in the preamble of claim 1.

Such an ink jet print head composed of edge shooter ink jet modules can be used in small, fast printers. These are used, for example, for franking machines for franking mail.

It is already known that inkjet printhead modules are constructed according to the edge shooter or face shooter principle and are detachably arranged in a holding means (First annual ink jet printing work-shop, March 26-27, 1992, Royal Sonesta Hotel, Cambridge, Massachusetts). However, the modules are spaced apart from one another with a high tolerance because the holding means here consists of a plate with elongated openings and two fastening means for each module, the openings lying vertically or obliquely one above the other. Therefore, the time delay of the control pulses from module to module is high and has to be set differently, which means an increased effort in controlling the drivers. In addition, a single module cannot be changed without the time delay for the controller having to be reprogrammed or set.

From US 47 03 333 an ink jet printhead is known which is constructed from face-shooter modules which are arranged at an angle to one another and can be detachably fastened in a holding means. Such inkjet printheads with an inclined arrangement of the modules to the surface of a recording medium produce a more uniform recording even when the thickness of the recording medium fluctuates. The ink jet no longer strikes perpendicularly but at an angle to the recording direction. A major disadvantage of the face shooter is its larger footprint, which faces the recording medium, which makes the distance between the nozzle lines of the modules large and only a few modules can be integrated in an inkjet printhead. This limits the recording density. This disadvantage cannot be completely remedied neither by the oblique arrangement of the modules in the recording medium transport direction nor by a laterally offset arrangement. The dimensions, in particular one with negative pressure, go into the printed image working printhead indirectly. The holding means has a common opening for the modules on the one hand, but on the other hand has a complicated shape which is correspondingly complex to manufacture. The manufacture of the printheads also requires a large number of manufacturing steps with small tolerances. With such a complex overall structure of each printhead, it is difficult to guarantee the required accuracy. The electronic control of these printheads with rows of nozzles offset from one another is also complex.

From DE 32 36 297 A1 the control of such laterally offset ink jet print heads arranged in a field is provided via presettable delay networks which are intended to compensate for the distance between the ink jet print heads along the transport direction of the recording medium.

Thus, such ink jet print heads can only be replaced by a person skilled in the art, who afterwards can again perform the complex mechanical and electrical adjustment work.

If the ink supply is based on capillary action, the ink supply containers are arranged separately from the printhead and the ink supply pressure has to be within the capillary pressure range, malfunctions frequently occur with ink jet printheads. If the printhead is clogged, the entire printhead must be replaced.

For this purpose, solutions for an inkjet printhead consisting of a single module are already known from the publications WO 91/06432 and WO 91/04861, wherein this is glued to an aluminum carrier plate and is closely adjacent to the ink supply system or a structural unit that can be inserted into a holder (Pressure module) forms. The holder has three spherical guide elements which engage in three differently shaped centering openings on one side of the printing module. For a higher print image resolution, several such print modules would have to be arranged, which then leads on the one hand to larger dimensions of the entire arrangement and on the other hand to tolerance problems when inserting the print modules, so that such print heads are not suitable for small, light franking printers.

From US 5 160 945 an edge shooter thermal ink jet print head composed of individual modules is known, which contains heating elements for expelling the ink. The individual modules, each with nozzle arrays, are arranged in a non-detachable manner at equal intervals in the x-direction on beam-shaped module carriers, which are fastened to flanges by means of bolts and are laterally offset from one another at a distance from one another in the y-direction. The distances are relatively large since, for reasons of stability, the module carriers must already have a relatively large thickness. It is difficult to keep the same distances exactly with the module carriers and flanges, especially if many module carriers are arranged one above the other. However, this means that the effort to compensate for the low module nozzle density and also the overall structure of the print head is too great to be able to use it in franking machines. Finally, the modules are not individually interchangeable.

Another edge shooter ink jet module that has already been proposed consists of at least three pieces of glass, that is to say an opening middle part and two side parts each having a row of ink chambers. A common row of nozzles is located on the front of the first side part. The two rows of ink chambers and the associated nozzles are offset from one another, with all nozzles in one row lie on the end face of the first side part and the ink chambers of the second side part are connected via channels in the middle part to the corresponding nozzles in the first side part or to the ink feed. According to this principle, an even more highly integrated module can be produced, which has only a single row of nozzles and at the same time forms an edge shooter ink jet in-line print head (ESIJIL print head). A spacer layer, consisting of the same material as the piezoelectric elements provided for driving the ink out of the ink chambers, is arranged between the respective sintered blocks of three glass parts and connects the sintered blocks to one another in a non-detachable manner. If the printhead is damaged during assembly or if the printhead becomes defective in later operation, the entire printhead must be replaced again. However, it is still difficult to achieve a high yield in the production of such printheads. So far, it has not been possible to assemble edge shooter ink jet modules into an ink jet printhead with a high recording density and with low production costs without, on the one hand, complex mechanical and electrical adjustment being necessary due to the manufacturing tolerances or, on the other hand, defects in the printed image arise.

It is an object to eliminate the disadvantages of the prior art in the holding of ink-jet print heads and to create an ink-jet print head composed of modules with a higher recording density and with low production costs.

Another object is that the modules can be removed individually and can be exchanged in an uncomplicated manner. It should be guaranteed that only the same module type is used correctly in the printhead and after an exchange of modules there are no defects in the printed image.

The object is achieved with the characterizing features of claim 1.

The invention is based on the fact that the ink jet printhead is constructed from several modules of the same type, a flat type of ink jet module consisting of several module parts and spacers being used, which ensures precise maintenance of the distance and the lateral offset between the exchangeable modules allowed.

In order to maintain the distance, the spacers are attached to the module part in a vertical position with their base surface on a reference plane, which is formed by one surface of a module part. The spacers of one module are brought into contact with at least those of another module.

In order to maintain the lateral offset, each module has a reference edge with a highly precise distance d from the first nozzle of its nozzle line.

A base plate located in the ink ejection direction has a common opening for the front edges of all modules. In the common opening of the base plate, offset stop edges for all modules are incorporated on one side, which is parallel to one of the second sides of the base plate. The reference edges of the modules are brought into contact with an associated stop edge of the base plate, so that there is a defined lateral offset c between the modules.

In the case of the edge shooter ink jet module type, the reference plane is that surface of a module part which lies parallel to the plane in which the nozzle channels are formed.

Advantageously, in the edge shooter ink jet in-line module type, all the nozzle channels are incorporated into the inner surface of the first module part, i.e. the distance between the inner surface of the module part and the nozzle channel plane becomes minimal and goes to zero. For each module, three such spacers are provided, which are located on its periphery and are fixed with their base surface standing on the inner surface of one module part, which carries the nozzle channels.

When using an edge shooter ink jet in-line printhead (ESIJIL printhead), in addition to the increased nozzle density, there are also reduced manufacturing costs and high accuracy, even with tolerance of the individual parts.

Based on the further task, a compact ink jet print head is proposed, which has several easily replaceable flat modules of the same structure and a U-shaped module carrier with a base plate as a positioning, holding and fastening means for the modules. The base plate located in the ink ejection direction again has a common opening for the front edges of all modules, which advantageously makes it possible to produce modular ink jet print heads for a vertical arrangement of the modules on the surface of a recording medium.

Two legs are arranged on two first sides of the base plate. Fastening elements for the modules are arranged on the two second sides of the base plate of the module carrier and adjustment means on the legs, which interact with the spacers of successive modules lying one above the other by a constant distance between the successive modules Modules.

Another advantage is the possible electrical monitoring of the module type via the spacers in order to guarantee that only the same module type is used correctly in the print head.

Figur 1a,

Aufbau eines Edge-Shooter-Ink-Jet-In-Line- Druckkopfes (Tintenzuführungsseite),

Figur 1b,

Einklinken eines ESIJIL-Moduls,

Figur 1c,

Aufbau des ESIJIL-Druckkopfes (Tintenstrahlseite),

Figur 1d,

Befestigung eines ESIJIL-Moduls im Modulträger,

Figur 2a,

erste Variante der erfindungsgemäßen Lösung für die Distanzstücke,

Figur 2b,

zweite Variante der erfindungsgemäßen Lösung für die Distanzstücke,

Figur 2c,

dritte Variante der erfindungsgemäßen Lösung für die Distanzstücke,

Figur 2d,

vierte Variante der erfindungsgemäßen Lösung für die Distanzstücke,

Figur 3a,

Seitenansicht des U-förmigen Modulträgers mit eingesetzten Modulen,

Figur 3b,

Vorderansicht der Basisplatte des Druckkopfes,

Figur 4,

Röntgenbild des erfindungsgemäßen, ESIJIL-Druckkopfmoduls in Draufsicht,

Figur 5a,

Detail des Röntgenbildes,

Figur 5b,

Schnitt durch die Linie A-A,

Figur 5c,

Schnitt durch die Linie B-B,

Advantageous developments of the invention are characterized in the subclaims or are shown in more detail below together with the description of the preferred embodiment of the invention with reference to the figures. Show it:

Figure 1a,

Construction of an edge shooter ink jet in-line print head (ink supply side),

Figure 1b,

Latching an ESIJIL module,

Figure 1c,

Structure of the ESIJIL print head (inkjet side),

Figure 1d,

Fastening an ESIJIL module in the module carrier,

Figure 2a,

first variant of the solution according to the invention for the spacers,

Figure 2b,

second variant of the solution according to the invention for the spacers,

Figure 2c,

third variant of the solution according to the invention for the spacers,

Figure 2d,

fourth variant of the solution according to the invention for the spacers,

Figure 3a,

Side view of the U-shaped module carrier with inserted modules,

Figure 3b,

Front view of the base plate of the printhead,

Figure 4,

X-ray image of the ESIJIL printhead module according to the invention in top view,

Figure 5a,

Detail of x-ray image,

Figure 5b,

Section through line AA,

Figure 5c,

Cut through the line BB,

FIGS. 1a to 1d show a composite print head, with detachable modules 1 and with a U-shaped module carrier as the holding means. The U-shaped module carrier 10 consists of a base plate 36 and legs 38 which are arranged on the base plate 36 on two opposite first sides.

The modules 1 are from the rear edge, i.e. shown from the ink supply side. A damping block 5 is arranged on the rear edge on the left and, in addition, electrical control feed lines are provided on the rear edge on the right - not shown in FIGS. 1a to 1c. In FIG. 1a, the modules have been shown opened instead of the control lines to show how the constant distance is effected by means of spacers 19 and / or 20. These are attached to the module standing vertically on a reference plane.

The structure of the ink jet print head according to the invention is described below in connection with the edge shooter ink jet in-line module (ESIJIL module) known from application P 42 25 799.9. It consists of at least 3 flat ceramic or glass parts 2, 3 and 4, which are sintered together and at least partially embedded in a protective coating 22 (synthetic resin). In the surface of only one ceramic or glass part 2, nozzles are incorporated on a nozzle channel plane 100, the nozzle openings of which form a line on the front of the module part 2. If modules based on the edge shooter principle are used for the inkjet printhead, the reference plane is formed by one surface of a module part 2 or 3, which lies parallel to the nozzle channel plane 100.

In FIG. 1a, four ESIJIL modules of the same structure are arranged in a module carrier 10, which performs a positioning, holding and fastening function. A distance a between the nozzle lines of the ESIJIL modules is maintained with defined accuracy by three spacers 20 per module. The time delay of the control pulses from module to module can thus be assumed to be constant. The spacers are fastened near the side edges of each module in the preferred variant on the module part which carries the nozzles and are perpendicular to the nozzle channel plane 100. They effect the same thickness b = 6 mm of the module at three points, whereas the Distance between adjacent synthetic resin surfaces of the modules can be tolerant. The spacers 20 can be attached by the synthetic resin coating.

The circular base surface 34 of the spacer cylinder 20 which is assigned to the nozzle channel plane 100 and has the larger diameter lies on the surface of the first part 2 carrying the ink chambers, specifically on that surface of the part 2 in which the nozzle channels are formed. The other circular base surface 35 facing away from the nozzle channel plane 100 is in contact with the spacer of the adjacent module or with an adjusting means 27 arranged on the closed side of the U-shaped module carrier 10 or 28. The module carrier 10 is preferably equipped with a stop surface 27 or stop screw and an adjusting screw 28 and / or spring element as adjusting means, between which the spacers 20 are clamped. The modules 1 are detachably fastened in the module carrier 10 with first fastening elements 23, 24 and second fastening elements 25, 26, the fastening elements 23, 24, 25, 26 being arranged on two opposite second sides of the base plate 36. In an advantageous variant, the fastening elements consist of leaf springs 23, 25 and screws 24, 26 and are arranged on the openly accessible second side of the U-shaped module carrier 10.

FIG. 1b illustrates the process of inserting a module into module carrier 10. For the purpose of insertion, the second fastening elements, namely leaf spring 25 and screw 26 on the side edge of module 1 that faces closer to the electrical connection lines or that faces away from the damping block have been removed, while the first fasteners 23 and 24 perform a holding function during insertion. The leaf spring 23 fastened to the module carrier with the screw 24 engages when inserted into the groove 32 of the side edge of the module 1 which faces the damping block 5 or faces away from the electrical connecting lines. The leaf springs 23, 25 are spaced apart by spring spacers 41, 42 which are attached to the base plate 36. The leaf springs 23, 25 can then better engage in corresponding grooves 32, 33 of each module 1, as a result of which each module 1 is then detachably fastened in the module carrier 10.

The part of the U-shaped module carrier facing the recording medium (not shown), ie the part facing away from the ink supply, of the U-shaped module carrier during printing has an opening 37 in a base plate 36 for that leading edge of all modules that carry the nozzle line. Offset stop edges 29 for all modules 1 are worked into the common opening 37 of the base plate 36 on one side, which is parallel to one of the second sides of the base plate. Each module 1 has a reference edge 21, which is brought into operative connection with an associated stop edge 29 of the base plate 36, so that there is a defined offset c between the modules 1. When a module 1 is inserted, the first reference edge 21 of the module 1 strikes the first stop edge 29 of the base plate 36 and the second reference edge 39 of the module 1 touches the second stop edge 30 of the base plate 36.

1c shows the inkjet printhead structure according to the invention in a front view. The nozzles lie in a line since the nozzle channels are formed in a plane 100 on the surface of the module part 2. By means of a stop edge 29, offset for each module 1, in the opening 37 of the base plate 36, a required defined offset c is achieved between the modules in order to print a coherent line with a high recording density with the nozzles of the four modules. The size of the offset corresponds to the distance of the nozzles in the nozzle line of a module 1 divided by the number of modules. With four modules and a nozzle spacing h = 0.8 mm, there is an offset c = 0.2 mm.

FIG. 1d shows the side view of the inkjet print head assembly according to the invention, with the modules inserted and adjusted, in section. Different, different force effects are exerted on the module used by different spring spacers 41, 42. The force of the first fastening means 23, 24 only causes the second reference edge 39 to be pressed against the second Stop edge 30.

The second spring spacer 42 realizes a smaller distance than the first spring spacer 41. The force effect of the second fastening means 25, 26 then brought into engagement with the groove 33 of the module 1 on the inserted module 1 holds its reference edges 21 and 37 against the stop edges 29 and 30 pressed in the opening 37 of the base plate 36 of the module carrier 10.

In a further embodiment variant, the base plate 36 can be constructed in two layers, a metal plate having the common opening 37 forming the first layer and simultaneously the front second stop edge 30 and a further larger common opening 40 in a second layer forming the lateral first stop edge 29 .

Depending on the position of the grooves 32 and 33 on the side edges of the modules and the intended force effect, the first fastening elements 23, 24 are spaced apart from the base plate 36 via a first spring spacer 41 and the second fastening elements 25, 26 via a second spring spacer 42.

In another variant - not shown - only the grooves 32 and 33 are arranged at a different distance from the front edge of the module 1, while the spring spacers 41 and 42 realize the same distance.

The first fastening elements 23, 24, the first and second spacing side pieces 41, 42 and the two legs 38 of the module carrier 10 can be produced in one advantageous variant from one piece by injection molding. The base plate 36 can also consist of a molded plastic part.

In a low-cost variant, the module carrier 10, apart from the second fastening elements 25, 26, is produced as a whole from one piece using the injection molding process. The second fastening elements 25, 26 are preferably made of metal.

Figures 2a to 2d show a first to fourth variant of the solution according to the invention for the spacers.

In a first variant - shown in FIG. 2a - the spacers are in two parts and each consist of a ball 19 and a spacer cylinder 20. The spacer cylinder 20 is the spacer section which is larger in diameter and which in the larger diameter openings of the second module part 4 and of the middle part 3 is inserted. Instead of the ball, a differently shaped spacer 19 can also be used.

In a second variant - shown in FIG. 2b - the spacers 20 are formed in one piece as a spacer cylinder with a conical extension directed away from the nozzle channel plane 100, which contacts the base surface 34 of the subsequent spacer of the next module from the outside.

Screws, not shown, are provided as adjusting means 27, 28, between which the spacers 20 are clamped one behind the other offset by the lateral offset c.

In a further variant - shown in FIG educated.

In a further variant, shown in FIG. 2d, spacer parts 19, 20, which are rotated through 180 ° and are shaped as in the third variant, are non-detachably connected to one another or formed integrally as a spacer cylinder 20 with a conical extension 19 . The surface of the middle part 3 lies parallel and directly on the surface of the module part 2, into which the nozzle channels are incorporated. On the surface of this middle part 3 there is now a spacer 20 inserted by 180 ° with its base surface 34 rotated vertically. Openings lying one above the other are incorporated into the module parts 2, 3 and 4, the opening in the first module part 2 being larger than the openings in the middle part 3 and in the second module part 4. The spacer 19, which is smaller in diameter, is arranged in the openings having the smaller diameter.

Screws 28 and a stop plate 27 are provided as adjusting means in the above-mentioned first, third and fourth variant, between which the spacers 20 are clamped one behind the other offset by the lateral offset c.

FIG. 3a shows a side view of the U-shaped module carrier 10 from the side edge of the modules, which has no reference edge. The connecting lines to the plug connector 8 closest to this module side edge are not shown. The U-shaped legs 38 of the module carrier 10 preferably have such an extent that the adjustment means can be arranged and with the lateral protection of the modules at the same time. In the preferred variant carried out, this results in an overall height of e = 21 mm together with the U-shaped legs 38 and the thickness of the base plate 36 for the module carrier.

FIG. 3b shows a front view of the base plate 36 with the dimensions f = 66 mm and g = 38 mm. The module carrier 10 is preferably made of plastic.

The lateral offset of the stop edges and thus the offset between the nozzles of the module 1 is e.g. c = 0.2 mm. The adjusting screw 28, the stop 27 and the spacers are made of metal and can be used to monitor the correct fastening of all modules or to identify the module type. For this purpose, the spacer can be contacted with conductor tracks on the outer module surface. The spacer 20 can - in a manner not shown - be fixed by soldering. This enables electronic control of the correct seating of the modules 1 via the spacers and an electronic monitoring circuit. If a module with defective spacers is used or is used inaccurately, the microprocessor of the franking machine can additionally detect and signal an error as a result of the monitoring.

The x-ray image of the ESIJIL printhead module 1 according to the invention shown in FIG. 4 in a top view illustrates the lateral offset of ink chamber groups 101 of a module part 2 containing first ink chambers and of module part 4 carrying ink chamber groups 102 of a second ink chamber and a defined distance d from a reference edge 21 to the first Nozzle N1 of a nozzle group 1.1, which is assigned to the ink chamber group 101. This distance d is achieved, for example, by etching the nozzle channels and the reference edge 21 simultaneously. In another variant, post-treatment is carried out by fine grinding. It is envisaged that the nozzles of the nozzle group 1.1 alternate with the nozzles of the nozzle group 1.2 within a single row of nozzles.

Therefore, a distance d 'to a first nozzle of the other nozzle group 1.2 can also be defined. The distance d or d 'is approximately 7 mm and must be observed with great precision, which is why the glass or ceramic parts have not been covered with synthetic resin and are exposed at this point of the reference edge 21.

The glass or ceramic parts - in a manner not shown in FIG. 4 - are each provided with a piezoelectric element 31 above each ink chamber and associated electrical conductor tracks, which are connected via an electrical connector 6 to a driver circuit board 7 having a plug connector 8 and not to a pressure control shown are connected.

Furthermore, in FIG. 4, a first opening 18 in a central part 3 to the ink supply opening 16 and the suction space 15, the second openings 14, which are in communication with the suction space 15 and the third openings 9, which the ink to the second nozzle group 1.2 feed proper nozzles, shown.

Each ESIJIL printhead module consists of at least 3 parts, with only the first module part 2 containing a group 102 of ink chambers carrying all the nozzles. A suction chamber 15, which is located in the first module part 2, is connected via a first elongated opening 18 arranged in the middle part 3 and via an ink supply opening 16 in the first module part 2 to a damping block 5 which compensates for the pressure fluctuations in the ink liquid which arise during operation. The central part 3 has a number of second openings 14 for supplying the ink to the chambers of a second module part 3 and a number of third openings 9 for supplying the ink from the chambers of the second module part 3 to the corresponding nozzles located in the first module part 2 conduct. The Openings for the fastening means 17 of the damping block 5 and for the spacers 20 are present in all module parts 2, 3 and 4.

The module part 4 containing the second ink chambers does not carry any nozzles but only the second ink chamber group 102, which is supplied with ink via the second openings 14 of the middle part 3. The associated nozzles are connected to the ink chambers of the second part 4 via the third openings in the middle part 3.

A detail of the X-ray image from FIG. 4 is shown enlarged in FIG. 5a. The ink chambers 11 of the first chamber group 101 located in the first module part 2 are assigned nozzles of the first nozzle group 1.1 in the same module part 2. The chamber 11 is supplied with ink from a suction chamber 15 via one of the channels 13. A corresponding section on the line A-A through the drawing in Figure 5a is shown in Figure 5b.

The chambers 12 of the second chamber group 102 located in the second module part 4 are assigned nozzles of the second nozzle group 1.2 in the other chamber part 2, as can be seen from the section B-B shown in FIG. 5c. Ink enters the chamber 12 of the second chamber part 4 from the suction chamber 15 located in the first chamber part 2 via another of the channels 13 and via one of the second openings 14 located in the middle part 3. From the chamber 12 to the corresponding nozzle located in the first chamber part 2 the nozzle group 12 is connected via a third opening 9 in the middle part 3.

In the middle piece 3 there are second openings 14 for supplying the second nozzle group 1. 2 with ink. Opposite the openings 9 in the respective center piece are openings 10 in the first Ink chamber-bearing module part 2 and a connection of the second ink chamber-bearing module part 3 for connecting the ink chambers of the respective second chamber group 102 to the nozzle channels of the second nozzle group 1.2 in the first ink chamber-bearing module part 2. The supply of the ink chambers 11, 12 in the respective first and second ink chamber module part 3 takes place from a respective common suction space 15 in the module part 2 carrying the first ink chambers. The ink supply to the suction space 15 takes place via an ink supply opening 16 in the module part 2 which is a side part of the module, and via corresponding openings 18 in the respective middle piece and further openings in the ink chamber-carrying parts 2, 4, 6.

To drive ink out of a chamber, a piezoelectric element 31, which is only shown in FIGS. 5b and c, can be arranged on the chamber surface or in the chamber and, when excited, exerts a pressure on the resilient chamber wall on the ink liquid in the chamber , which leads to the discharge of an ink jet from the nozzle connected to the chamber. Such a piezoelectric element 31 (PZT crystal) is preferably arranged on the chamber surface. For example, the chamber 11, 12 is separated from the element 31 by a thin layer 30 consisting of the material of the chamber part 4, which is so elastic that the bending energy of the element 31 is only insignificantly damped.

The invention is not limited to the present embodiment. Rather, a number of variants are conceivable which make use of the solution shown, even in the case of fundamentally different types.

Claims (17)

Modular inkjet printhead, the modules of which are equipped with means for supplying and expelling ink from a chamber each associated with a nozzle and fastened in a module carrier which has an opening for the front edges of all modules and fastening elements for each module,
characterized by
that spacers (20) are arranged with their base surface (34) standing vertically on a reference plane of each module (1) and the spacers of at least one module are brought into contact with those of another module. Modular inkjet printhead according to claim 1,
characterized by
that the spacers are made in one piece (20) or in several parts (19, 20). Modular ink jet print head, according to claims 1 to 2, characterized in that the front edges of such modules (1) are inserted into the common opening which, according to the edge shooter principle, nozzles in a nozzle line on the front edge of a module part (2) carrying ink chambers. and have a side reference edge (21), the reference edge (21) of each module (1) having an associated stop edge (29), each on one side in the common opening (37) of a base plate (36) of the module carrier (10) is incorporated for each module (1), is brought into abutment, so that offset abutment edges (29) result in a defined lateral offset c between the modules (1) for these modules (1),
that three spacers (20) are arranged near the side edges of each module (1) within openings for receiving them in the module and that the reference plane is formed by an inner surface of a module part (2) or (3), one Nozzle channel level (100) is parallel with a defined distance to the surface of the module part (2) or (3). Modular ink jet print head, according to claims 1 to 3, characterized in that the nozzle channel plane (100) is at a small, zero distance from the inner surface of the module part (2) or (3) on which the base surface (34) of the spacers ( 20) is present. Modular ink jet print head according to one of the preceding claims 1 to 4, characterized in that the three spacers (20) rest on the inner surface of a module part (2) or (3) in such a way that they meet the larger one on the nozzle channel plane (100) Diameter base surface (34) lie and their attachment is carried out by embedding the module in a synthetic resin or similar non-conductive material or by soldering the spacers to conductor tracks located on the outer module part surface. Modular ink jet print head, according to one of the preceding claims, characterized in that the spacers (20) are formed in one piece as a spacer cylinder with a conical projection, that openings lying one above the other are incorporated in the module parts (2, 3 and 4), the opening in at least a module part (2) or (3 and 4) is larger than the openings in the other module parts (3 and 4) or the other module part (4) of a module (1) and that the smaller diameter spacer in the smaller diameter having openings is arranged. Modular inkjet print head according to one of the preceding claims, characterized in that the spacers (19, 20) consist of an electrically conductive material and are connected to the modules and to a monitoring circuit for electronic control of the correct seating of the modules. Modular ink jet print head according to one of the preceding claims, characterized in that legs (38) lie on two opposite first sides of the base plate (36) and a U-shaped module carrier (10) is formed as holding means for the modules (1), that adjusting means (27, 28) are arranged on the legs (38) in such a way that they can be operatively connected to the spacers (20) in order to maintain a constant distance a between the nozzle lines (100) and successive modules, the spacers (20 ) bear on one side on the spacer (20) of the adjacent module (1) or on the adjusting means (27, 28) and that fastening elements (23, 24, 25, 26) for the modules (1) on the two opposite second sides of the base plate (36) are arranged. Modular ink jet print head according to one of the preceding claims, characterized in that spacers (19, 20) are connected to the modules and to the monitoring circuit via the adjustment means (27, 28) made of an electrically conductive material for electronic control of the correct seating of the modules . Modular ink jet print head, according to claim 8, characterized in that the fastening elements are springs (23, 25) and screws (24, 26), the springs (23, 25) with the screws on the base plate (36) of the U-shaped module carrier (10) are releasably attached and the springs engage in the corresponding grooves (32, 33) on the side edges of the modules (1). Modular inkjet print head according to one of the preceding claims, characterized in that the spacers each consist of a ball (19) and a spacer cylinder (20). Modular ink jet print head according to claim 10, characterized in that grooves (32 and 33) are arranged at a different distance from the front edge of the module (1). Modular ink jet print head according to claim 12, characterized in that, depending on the position of the grooves (32 and 33) on the side edges of the modules (1) and the intended force effect by fastening elements, the first fastening elements (23, 24) via a first spring spacer (41) and the second fastening elements (25, 26) are spaced apart from the base plate (36) via a second spring spacer (42). Modular ink jet print head, according to claim 3, characterized in that, in order to maintain the lateral offset c, such modules are used with a highly precise distance d from the first nozzle of the nozzle line of the module to the reference edge (21) which is etched simultaneously with the reference edge (21) Includes nozzle channels. Modular ink jet print head, according to claim 8, characterized in that the adjusting means per module consists of two screws (27, 28) or in each case one screw (28) and stop surface (27) or of screws (28) and / or a spring element and a stop surface ( 27) exist. Modular ink jet print head according to one of the preceding claims 1 to 2, characterized in that the reference plane is formed by one surface of a module part (2) or (4) and in that three spacers (20) in the vicinity of the side edges of each module (1) are fixed with their base surface (34) standing vertically on the surface of a module part (2) or (4). Modular ink jet print head according to one of the preceding claims, characterized in that the spacers (20) set the distance between four successive modules.

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