EP0726152A2 - Method of manufacturing an inkjet printhead - Google Patents

Abstract

An edge shooter ink jet in lint printer has a number of arrays of ink jet nozzles (1.1,1.2) that are arranged in parallel in a horizontal direction within the head. Ink is supplied to the nozzles by groups of chambers (12-1-104) and these in turn are coupled to the main ink jet reservoirs (151.152). The nozzles and chambers can be offset in the vertical direction and adjacent nozzles spacing provides overlap in printing. The assembly of the heads are formed using three ceramic or glass parts, with one plate having all the nozzles and a second the supply chambers.

Description

The invention relates to a manufacturing method for an ink jet print head according to the type specified in the preamble of claim 1.

Such an ink jet printhead can be used in small, fast printers. These are used, for example, for franking machines for franking mail.

It is known that ink jet print heads are constructed according to the edge shooter or face shooter principle (First annual ink jet printing workshop, March 26-27, 1992, Royal Sonesta Hotel, Cambridge, Massachusetts). Efforts have been made to minimize the dimensions of the chambers to increase the nozzle density. The nozzle chambers have also been arranged in a concentrated manner towards the front edge. However, this principle only makes sense for inkjet modules with a few nozzles in a row and fails with a large number of nozzles.

It is well known that a first generation of inkjet printheads based on the edge shooter principle were constructed from individual pulse emitters, which consist of an elongated ink chamber with a rectangular cross section and a piezo crystal glued on top of it (BIS CAP Ink Jet Printing Conference, Monterey, California) , November 11-13, 1991).

In a later generation, a nozzle plate was then placed in front of a one-piece, multi-chamber ink jet printhead. The chambers are no longer parallel to each other with the smaller chamber area, but now with the larger chamber area. The piezo crystals form the chamber walls (shared wall concept, Ink Jet Printing Conference, November 11-13, 1991).

DE 34 45 761 A1 discloses a method for producing a transducer arrangement from a single plate of a transducer material. After coating the lower plate surface with a membrane layer, material is removed from the upper surface in order to produce separate areas which are arranged on the membrane above each pressure chamber (area 25.4 mm * 2.54 mm). This eliminates the need for an adhesive bond between the transducer material and the membrane and the uniformity of all distances is improved. The resulting nozzle spacing is, however, relatively large.

Furthermore, from US 46 80 595 a face shooter with a nozzle line between two groups of ink chambers is known, which has a doubled nozzle density. Each rectangular pressure chamber is assigned a supply channel and a nozzle as well as a vibrating plate with a piezoceramic element. The disadvantage here, however, is that the pressure waves occurring in the ink supply and in each chamber can cause crosstalk to other pressure chambers. This crosstalk can only be eliminated subsequently by very complex measures. Another disadvantage is that these inkjet printheads have to be manufactured in a complex and expensive manufacturing process.

From US 47 03 333 it is also known to produce such ink jet print heads constructed from face shooter modules arranged at an angle to one another for an inclined arrangement relative to the surface of a recording medium. Ink jet printheads with an inclined arrangement to the surface of a recording medium produce a more uniform recording even when the thickness of the recording medium varies. However, the manufacture of such printheads requires a large number of manufacturing steps. It is difficult to guarantee the required accuracy with such a complex overall construction of each printhead. The electrical actuation of such printheads with rows of nozzles which are offset from one another during operation is also complicated.

The double nozzle density already achieved in the face-shooter-ink-jet module with two groups of ink chambers arranged symmetrically to the nozzle line has so far not been achieved with edge-shooter ink-jet modules with one row of nozzles. To double the image density To achieve this, several rows of nozzles are staggered horizontally and vertically.

Such an offset arrangement of two rows of nozzles is also known for an edge shooter module - shown in FIG. 2 (First Annual Ink Jet Printing Workshop, March 26-27, 1992, Royal Sonesta Hotel, Cambridge, Massachusetts). Such a module consists of a total of only three parts (glass pieces), a central part with openings and two side parts, each with a row of ink chambers and a row of nozzles on the front side of the respective side part. The two rows of ink chambers and the rows of nozzles on the front of the respective side part are offset from one another, which again brings with it the disadvantages already mentioned when assembling the module and when actuating.

These disadvantages are exacerbated when an ink print head is composed of several such modules. The offset of the individual rows of nozzles must be exactly the same. In addition, each module would have to be individually connected to an ink reservoir via an ink supply line and a filter.

In the case of a staggered arrangement of two rows, each with a low nozzle density in each row, the minimum spacing between the nozzles cannot be further reduced due to a required minimum size of the ink chamber.

Due to the manufacturing process, it is impossible to achieve the same nozzle size for all nozzles, because channels have to be etched into separate glass pieces. Even small differences in size or material between the glass pieces lead to deviations in the nozzle shape and position.

It is an object to eliminate the disadvantages of the prior art and to provide a manufacturing process with a low manufacturing cost for an ink jet print head with a high nozzle density per row.

The object is achieved with the features of claim 1.

Starting from the objective of producing ink jet print heads for an inclined arrangement to the surface of a recording medium in order to produce a more uniform recording even with a fluctuating thickness of the recording medium, an ink jet print head having an in-line module with an edge ejection is proposed .

The process for manufacturing the inkjet printhead is based on the CAD development of a printhead design and a mask production for a photosensitive glass plate.

In order to produce the parts to be removed from the glass plate which are sensitive to etching agents, the masked glass plates are exposed at least once to radiation with a corresponding wavelength of UV light with subsequent heat treatment.

In a parallel processing process, the areas to be removed are then removed (etched out) from the plate and then the individual parts for the middle part and the parts carrying the chambers are separated.

This is followed by separate manufacturing process steps for the chamber supporting parts to manufacture the ink chambers and nozzles. The duration of the etching bath determines the layer thickness of the removed material.

Three individual parts, each consisting of two Chamber-bearing parts and a middle part, are aligned and tacked together and then annealed.

Finally, the nozzle channels and the cavities (chambers) and the outer edge of the module are specially treated before the printhead is contacted and installed.

The invention is based on the fact that when the edges are ejected, the row of nozzles with a high number of nozzles can be accommodated in a side part of a module. For the first time, a higher nozzle density can be achieved in the manner according to the invention, completely independently of the dimensions of the ink chambers.

The dimensions of the ink chambers can now even be increased without reducing the nozzle density.

• Durch die in demselben Glasstück angeordneten Düsen, ist es möglich, für alle Düsen eine gleichbleibende Düsengröße und einen gleichen Abstand zu erreichen. Das ist dann der Fall, wenn vor dem Diffusions-Bond-Prozeß entsprechende Kanäle in das das Seitenteil des Moduls bildende Glasstück geätzt werden. Das reduziert auch die Herstellungskosten.
• Gegenüber der üblichen Konstruktion mit einer horizontalen Ausrichtung von zwei Reihen von Düsen ist ein Überlappen des jeweils zweiten Kammern tragenden Teils mit einer versetzten Kammergruppe mit größerer Toleranz möglich.
• Die erfindungsgemäße vertikale Ausrichtung des Teils mit den Düsen und eines Kammern tragenden Teils mit einer seitlich versetzten Kammergruppe ist unkritisch, da alle Düsen nur auf einer Seite des Druckkopfes sind. Dies reduziert auch die Kosten.
• Die Düsenreihe macht es in unaufwendiger Weise möglich, den Druckkopf in einer geneigten Anordnung zum Aufzeichnungsträger anzuordnen.
• Die elektrische Ansteuerung des Tintenstrahldruckkopfes kann einfacher ausgeführt werden, weil keine Kompensation des Düsenreihenabstandes durch zeitliche Staffelung der Drucksteuersignale erforderlich ist.

In addition to the increased nozzle density of the edge shooter ink jet in-line print head (ESIJIL print head), the other advantages are:

• Due to the nozzles arranged in the same piece of glass, it is possible to achieve a constant nozzle size and an equal distance for all nozzles. This is the case if appropriate channels are etched into the glass piece forming the side part of the module before the diffusion bonding process. This also reduces manufacturing costs.
• Compared to the usual construction with a horizontal alignment of two rows of nozzles, an overlap of the part carrying the second chamber with an offset chamber group with greater tolerance is possible.
• The vertical alignment of the part according to the invention with the nozzles and a part carrying the chambers a laterally offset chamber group is not critical since all nozzles are only on one side of the print head. This also reduces costs.
• The row of nozzles makes it possible in a straightforward manner to arrange the print head in an inclined arrangement relative to the recording medium.
• The electrical control of the inkjet printhead can be carried out more simply because no compensation of the nozzle row spacing is required by staggering the pressure control signals over time.

Such an inkjet print head can advantageously be constructed from a plurality of modules, only one of the modules carrying the row of nozzles or consisting of a multi-part module. It is furthermore provided that the end edge of the chamber-bearing part, which carries the row of nozzles, is arranged at the edge or in the middle of a module.

Figur 1a,

Prinzip eines Edge-Shooter-Ink-Jet-Druckkopfes nach dem Stand der Technik

Figur 1b,

Prinzip eines Face-Shooter-Ink-Jet-Druckkopfes nach dem Stand der Technik

Figur 1c,

Prinzip des erfindungsgemäßen Aufbaues eines Edge-Shooter-Ink-Jet-In-Line-Druckkopfes

Figur 2,

Aufbau eines Edge-Shooter-Ink-Jet-Druckkopfes nach dem Stand der Technik

Figur 3,

Aufbau des erfindungsgemäßen ESIJIL-Druckkopfes in einer ersten Variante

Figur 4,

Röntgenbild des erfindungsgemäßen ESIJIL-Druckkopfes in Draufsicht,

Figur 5a,

Detail des Röntgenbildes

Figur 5b,

Schnitt durch die Linie A-A

Figur 5c,

Schnitt durch die Linie B-B

Figur 6a,

Detail des Röntgenbildes einer zweiten Variante des erfindungsgemäßen ESIJIL-Druckkopfes in Draufsicht,

Figur 6b,

Schnitt durch die Linie A-A

Figur 6c,

Schnitt durch die Linie B-B

Figur 6d,

Röntgenbild der Frontansicht

Figur 7a,

Frontansicht einer dritten Variante des erfindungsgemäßen ESIJIL-Druckkopfes,

Figur 7b,

Röntgenbild der Frontansicht nach Figur 7a

Figur 8,

Herstellungsverfahren für den erfindungsgemäßen ESIJIL-Druckkopfes,

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,

Principle of an edge shooter ink jet print head according to the state of the art

Figure 1b,

Principle of a face shooter ink jet print head according to the state of the art

Figure 1c,

Principle of the construction according to the invention of an edge shooter ink jet in-line print head

Figure 2,

Construction of an edge shooter ink jet print head according to the state of the art

Figure 3,

Construction of the ESIJIL print head according to the invention in a first variant

Figure 4,

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

Figure 5a,

Detail of the x-ray image

Figure 5b,

Section through the line AA

Figure 5c,

Section through the line BB

Figure 6a,

Detail of the x-ray image of a second variant of the ESIJIL printhead according to the invention in plan view,

Figure 6b,

Section through the line AA

Figure 6c,

Section through the line BB

Figure 6d,

X-ray image of the front view

Figure 7a,

Front view of a third variant of the ESIJIL print head according to the invention,

Figure 7b,

X-ray image of the front view according to FIG. 7a

Figure 8,

Manufacturing process for the ESIJIL printhead according to the invention,

FIG. 1a shows the known principle of an edge shooter inkjet print head in a perspective view. It consists of a module with two rows of nozzles offset from one another in the y direction. A first group 101 of ink chambers belongs to the nozzle group 1.1 of the first row and a group 102 of ink chambers to the nozzle group 1.2 of the second row.

FIG. 1b shows the known principle of a face shooter ink jet ink jet print head in a perspective view. It consists of a module, in the base of which two nozzle groups 1.1 and 1.2 offset in the z direction lie in a row. A group of ink chambers 101 and 102 for the nozzle group 1.1 and for the offset nozzle group 1.2 is supplied with ink from a suction chamber 151 and 152, respectively.

FIG. 1 c shows a perspective view of the principle according to the invention of an edge shooter ink jet in-line print head (ESIJIL). It consists of a module, on the end face of which k ≧ 2 nozzle groups 1.1, 1.2, etc., which are horizontally offset from one another, lie in a row. The ink flow from the chamber groups 101-104 in the volume of the module is directed to the front edge of the first chamber-bearing part, which forms a side part of the module. The chambers of a group 101-104 are staggered in the y direction and their associated outgoing ink channels are guided to the printing edge in such a way that they form nozzles 1.1-1.4 which are in a row but are nevertheless very close apart. This is achieved in FIG. 1c in which the outgoing ink channels have a certain lateral offset in the z direction. Likewise, in another embodiment variant, the chambers 101-104 themselves can have this lateral offset in the z direction. The arrangement of such arrangements finally results in the desired number of nozzles in a row. For the sake of clarity, only two such arrangements are drawn in FIG. 1c. The lateral distance between the nozzles in the z direction is much smaller than the lateral distance between two chambers 101 and 101 or 102 and 102, which are adjacent in the z direction, etc. The ink drops are formed from the Nozzles ejected in the x direction. The axes x, y, z are orthogonal to each other. The addition of further chambers 105, 106 etc. in the y direction is possible in principle and is only limited by the effort. The inventive principle already has its positive effect, namely the formation of only one row of nozzles with a minimal nozzle spacing, with two chamber groups 101 and 102.

The construction of a known two-row edge shooter ink jet module shown in FIG. 2 consists of 3 ceramic or glass parts. A first part, which bears a first chamber group on its left side, is connected via a middle part to a second part, which bears a second chamber group on its right side, in the y direction such that the chambers lie against the inside of the middle part and laterally to one another are offset (horizontally). Each chamber is connected to a suction chamber via a first channel and to the front edge of the module via a second channel. Each of the second channels forms a nozzle. It is relatively difficult to exactly maintain the distance between the two rows of nozzles. However, deviations lead to deviations in the print image if the two rows of nozzles are controlled at a constant time, which reduces the print quality. The middle part has a first opening which connects the suction spaces of both outer parts to one another and to an ink supply opening. There are also openings for the fasteners.

The module of a first variant of an ESIJIL printhead according to the invention (k = 2) shown in FIG. 3 also consists of 3 parts, but the part 2 containing the first chambers carries all the nozzles 1, the middle part 3 having a number of second and third openings 14 and 9 in addition to the first opening 18, which connects the ink supply opening 16 to a suction space 15, not shown in FIG. 3. An ink chamber group 101 and the suction space 15 are located on the left side of the first part 2, which is not visible in FIG. 3. The part 4 containing the second 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 further nozzles are connected to the ink chambers of the second part 4 via the third openings in the middle part 3. Parts 2 - 4 are assembled in the direction of the y-axis.

The x-ray image of the ESIJIL printhead module according to the invention shown in FIG. 4 in plan view illustrates the in-line arrangement of the nozzles and the lateral offset of the ink chamber groups 101 of the first chamber-bearing part 2 and the group 102 of the second chamber-bearing part 4 the position of the first opening 18 in the middle 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 supply the ink to the nozzles of the second nozzle group 1.2. It is contemplated that the nozzles of nozzle group 101 alternate with the nozzles of nozzle group 102 within the row of nozzles.

A detail of the X-ray image from FIG. 4 is shown enlarged in FIG. 5a. The chambers 11 of the first chamber group 101 located in the first part 2 are assigned nozzles of the first nozzle group 1.1 in the same 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 AA through the drawing in Figure 5a is shown in Figure 5b. The chambers 12 of the second chamber group 102 located in the second part 4 are assigned nozzles of the second nozzle group 1.2 in the other chamber-carrying part 2, as can be seen from the section BB shown in FIG. 5c. Ink passes from the suction chamber 15 located in the first chamber-bearing part 2 via a other of the channels 13 and via one of the second openings 14 located in the middle part 3 into the chamber 12 of the second chamber-bearing part 4. From the chamber 12 to the corresponding nozzle in the first chamber-bearing part 2 there is a connection via a respective one third opening 9 in the middle part 3.

6a, b, c and d show a second variant of the solution according to the invention. FIG. 6a shows a top view of a detail as an X-ray image, and FIG. 6d shows a front view of a print head as an X-ray image. Sections C-C, D-D and E-E are superimposed on the x-ray image in the view in FIG. 6d. The position of the ink chamber groups 101, 102, 103 and 104 can be seen from this in connection with FIG. 6a. FIG. 6b shows a superimposition of sections through the lines A-A and A1-A1 of FIGS. 6a and 6d. FIG. 6c shows a superimposition of sections through the lines B-B and B1-B1 of FIGS. 6a and 6d.

The in-line nozzle groups 1.1 - 1.4 of k = 4 chamber groups 101, 102, 103, 104 are each in a first part 2, which itself has only a first 101 of the k = 4 chamber groups. A respective second nozzle group 1.2 in the first part is connected to a chamber 12 of the second chamber group 102 in the second chamber-carrying part, which is arranged offset with respect to a chamber 11 of the first chamber group 101 of the first chamber-carrying part 2, the second chamber group 102 passing through Openings 14 in the center piece 3 is supplied with ink.

According to the invention, there are second openings 14 in the center piece 3 for supplying the second nozzle group 1. 2 with ink. Opposite the openings 9 in the respective middle piece are openings 10 in the first chamber-carrying part and a connection of the second chambers supporting part for connecting the chambers of each second chamber group 102 with the nozzle channels of the second nozzle group 1.2 in the first chamber-carrying part.

The ink chambers 11, 12 are supplied in each of the first and second chamber-carrying parts from a common suction chamber 15 in the first chamber-carrying part. The ink is supplied to the suction chamber 15 via an opening 16 in that part 2 which forms a side part of the print head, and via corresponding openings 18, 22 in the respective center piece and further openings 17, 19, 21 in the parts 2, 4, 6 carrying the chambers and an opening 20 in the spacer 5.

A piezoelectric element 31, not shown in FIGS. 1 through 6a, serves as a well-known means for driving ink out of a chamber and can be arranged on the chamber surface or in the chamber in order to exert pressure on the flexible chamber wall when it is excited To exert ink liquid in the chamber, causing an ink jet to emerge from the nozzle connected to the chamber. Such a piezoelectric element 31 is arranged on the chamber surface in FIGS. 6b, 6c and 6d. For example, the chamber 12 is separated from the element 31 by a thin layer 30 consisting of the material of the chamber-carrying part 4, which is so elastic that the bending energy of the element 31 is only insignificantly damped. A spacer 5 has a corresponding recess 32 for the piezoelectric element 31.

In a further advantageous embodiment of the inventive concept, an elongated opening in the chambers-carrying parts are each provided with a correspondingly rotated by 90 ^o in the elongated aperture Middle parts and spacers are connected. An inkjet print head constructed from such individual modules has no tolerance problems when assembling.

Because of the rectangular openings which are visible and indicated in FIGS. 6a, b, c, complicated alignment with a very high accuracy when joining the parts is no longer necessary, as was previously required when joining parts with offset rows of nozzles. In another variant, the shape of the openings can be oval or an elongated hole, the small diameter of the openings determining the passage cross section for the ink flow. If there is a greater deviation from the round or rectangular cross section, the openings 9 and 10 can also be arranged in two rows on lines C-C and D-D.

It is envisaged that, in the case of a structure consisting of several modules, a first module carrying the row of nozzles consisting of two chambers 2 and 4, the chamber groups 101 and 102 of which face a central part 3 and at least a second module consisting of two chambers 6 and 8 and a middle part 7, that each module has a suction space 15, 25, that there is a spacing part 5 at least between the modules, which has an ink supply opening 20 and ink through openings 23, 26, which are assigned to the chambers of the second module, and a recess 32 for the means for ejecting 31 ink from a chamber, that the openings 23, 24 are connected to the third openings of the chamber-carrying parts and the middle parts in order to supply ink to the nozzles from the respective chambers, that the suction spaces 15, 25 each module via second openings 14, 24 with the chambers of the chamber groups 101, 102, 103, ..., 10k v are connected to supply ink and that in each module there are first openings 18, 22 for the ink supply to the To secure intake spaces.
The manufacturing process assumes that a module is composed of 3 parts each and is provided with piezoelectric elements and contacted. A second module is joined together with the first module via a spacer 5 to form an ESIJIL printhead, the second module with parts 6, 7, 8 not having any nozzles, but only corresponding openings which correspond to the openings provided in parts 2 , 3, 4 of the first module are connected.

In a third variant, an ESIJIL printhead is built from a single, multi-part module. FIG. 7a shows a front view with the in-line nozzle row and FIG. 7b shows an X-ray image of the front view or an overlay of the sections through the lines C-C and E-E. All third openings lie on this line C-C. There are no further openings on a line D-D. It can be seen that the nozzle dimensions alone determine the maximum number of nozzles in the row. If there is a need for enlarged chamber dimensions, only the volume of the print head would have to be increased. Of course, it is also possible, if required, to solve higher tolerance requirements by means of the measures with third openings on a line D-D explained in FIG. 6.

In contrast to the spacer parts in FIGS. 6, the spacer parts here are in two parts and consist of the same material as the piezoelectric elements (marked in black). These elements are worked out from the piezoelectric material, which is arranged on the chamber surface, but the edge is retained and cavities 32 are formed only in the immediate vicinity of the elements 31. Ink supply openings as well as second and third openings are worked out in the edge. After the piezoelectric elements are worked out, these are contacted, conductor tracks also being able to run on the chamber bottom and / or outside on the layer 30.

FIG. 8 shows the individual steps for a manufacturing process for the ESIJIL printhead according to the invention.

The process for manufacturing the inkjet printhead is based on the CAD development of a printhead design and a mask production for a photosensitive glass plate.

Using masks, which have the structure of the various parts to be produced, a photosensitive plate made of amorphous glass is masked and exposed to UV radiation. The irradiated areas can later be etched approximately 100 times faster than unirradiated areas. After heat treatment, UV radiation is repeated.

In order to produce the parts to be removed from the glass plate which are sensitive to etching agents, the masked glass plates are exposed at least once to radiation with a corresponding wavelength of UV light with subsequent heat treatment.

In a parallel processing process, the areas to be removed are then removed (etched out) from the plate and then the individual parts for the middle part and the parts carrying the chambers are separated.

The parallel processing steps for several parts of a module include masking and then etching the through openings.

This is followed by separate manufacturing process steps for the chamber supporting parts to manufacture the ink chambers and nozzles. The duration of the Etching bath determines the layer thickness of the removed material.

Before the ink chambers are manufactured, the old mask layer is removed by fine grinding the surface of the chamber parts. The surface is then masked in the areas that should not be deep-etched. After the etching of the ink chambers, the individual parts are finely ground to a final dimension and then masked to produce the supply channels and the ink nozzle channels, which should have a lower depth than the chambers. The material is removed again by etching. In special cases, only the etching sensitivity of the UV-irradiated areas of the material is used and a mask can be omitted.

It is envisaged that etchants with different concentrations are used for the three areas in order to be able to remove the corresponding areas with different depth accuracy, the depth accuracy when etching the areas for through bores being lower than when etching very flat areas for the channels in the parts carrying the chambers and first the through holes, then the chambers and then the nozzle channels are etched. It is further contemplated that the thickness of the bottom layer 30 is monitored as the chambers are etched and that the thickness of the bottom layer 30 of the chambers required to complete the manufacture of the chambers is achieved by fine grinding each of the parts carrying the chambers.

When separating the individual parts, the finished middle parts are separated out.

In each case three individual parts, each consisting of two parts carrying a chamber and a middle part, are aligned and tacked together and then annealed.

The individual parts are connected in a module, with the individual parts being aligned. After the individual parts have been tacked together, a module is created, which is then tempered. During tempering, a phase transition from amorphous to crystalline takes place in the glass material.

When cutting off the nozzle tips with a rotating cutting disc, a straight front edge is created. A final surface is achieved by fine grinding.

Finally, the nozzle channels and the cavities (chambers) and the outer edge of the module are specially treated before the printhead is contacted and installed.

Rinsing with a first suitable commercially available liquid creates a hydrophilic inner coating. A hydrophobic outer coating is achieved by treating the front edge with a second suitable liquid. After the top layer has hardened, the nozzles are finished.

The application of the electrical conductor tracks to the chamber surface, the application of the piezo crystals and the contacting are carried out in a manner known per se. The piezo crystals can be glued on individually and then hardened. On the other hand, a layer of piezoelectric material can also be applied to the chamber surface, which is then structured and contacted. Coating can be done by sputtering.

Finally, a nozzle cleaning is carried out using compressed air.

The manufacture of chambers and through holes in a further variant of the manufacturing process, the individual parts can be carried out in one step. This requires that the UV exposure be repeated through different masks before the plate is etched. Another possibility is UV exposure with different intensities. The plate then has a different sensitivity during etching in different areas. The dividing line between the individual parts is also etched, which simplifies subsequent separation. The mask to be applied contains recessed areas for the chambers and the bores at the same time. After the etching, fine grinding takes place to the final dimension when the thickness of the layer 30 on the chamber bottom is reached. The production of the ink nozzles and the piezoelectric elements, as well as the edge production, is carried out in the known manner mentioned above. In this variant the bottom of the chamber is used for contacting. Then the plate is divided into individual parts, which are then assembled into a module.

In a further variant, piezoelectric elements are also fitted or contacted only or the back of the chamber surface. When contacting before separating, it is advantageous that the middle parts can also be provided with conductor tracks. This means that cables can be routed from the other layers to the upper layers of the module without crossing, even if a large number of elements have to be contacted. The individual module parts are aligned and annealed, with a phase transition from amorphous to crystalline. It is envisaged that spacer parts lie between the modules or are additionally arranged and that the spacer parts are produced from the plate material or from a layer of piezoelectric material applied to the surface of the plate, structuring being carried out by etching. A printhead can be assembled from several modules or consists of only one module that follows has externally guided conductor tracks that are contacted externally. The printhead is then housed in a housing and can be tested for functionality to remove faulty copies. In a further embodiment, the plate material or a part of the individual parts consists of a photosensitive ceramic. Glass parts and / or ceramic parts can also be connected to one another by an adhesive connection.

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 (23)

Process for the production of inkjet printheads, characterized by the steps: - parallel plate processing in the production of through holes in all parts, - special machining of parts carrying chambers, Connecting the individual parts to at least one module with subsequent annealing, - applying and contacting the piezoelectric elements with applied conductor tracks, - Assemble to the printhead. A method according to claim 1, characterized in that masks are created for the pretreatment process of plate material in order to be able to remove from the plate material areas for at least the ink chambers, nozzle channels and feed channels, for the suction space and for through openings in a targeted manner, that plates in the pretreatment process over masks exposed at least once to UV radiation of the appropriate wavelength with subsequent heat treatment, so that the areas to be removed are etched out of the plate in a parallel process. Method according to claim 2, characterized in that in the pretreatment process of the plates all areas to be removed are exposed to UV light of the same wavelength and intensity, that a first mask is applied to the plate before the photosensitized regions of the plate are etched out, thereby etching first regions out of the plate, that after the first regions have been etched out, the first mask is removed again and a second mask is applied to the plate in order to etching out second areas from the plate, that after the second areas have been etched out, the second mask is removed again and that third areas are etched out of the plate. A method according to claim 2, characterized in that different masks are used for the plate material in the pretreatment process, areas of the plate being exposed to more or stronger radiation with UV light of corresponding wavelengths than other areas of the plate, whereby the areas of the plate material which are differently sensitized to the etchant, the result is that in the process of parallel plate processing, a mask is applied to the plate for areas to be removed at different depths and that an etchant of a certain concentration is used. Method according to Claim 2, characterized in that etching agents with different concentrations are used for the three areas in order to be able to remove the corresponding areas with different depth accuracy, the depth accuracy when etching the areas for through bores being less than when etching very flat areas for the channels in the chambers carrying parts and first the through holes, then the chambers and then the nozzle channels are etched. Method according to claims 2 to 5, characterized in that the thickness of the bottom layer (30) is monitored during the etching of the chambers and that the thickness of the bottom layer (30) of the chambers required to complete the manufacture of the chambers is carried out by fine grinding each of the chambers Parts is reached. Method according to one of the preceding claims 1 to 6, characterized in that, after the parallel processing of the plate material, individual parts are separated from the plate and further processed separately. Method according to Claim 7, characterized in that after the through-bores have been etched, the individual parts are separated in all the individual parts, that the parts carrying the chambers are masked after the surface has been fine-ground so that cavities and / or ink chambers in the Chamber-bearing parts are produced that the depth of the chambers by fine grinding to the final dimension of one surface, that the required thickness of the bottom layer (30) at the base of the chamber is precisely adjusted by fine grinding to the final dimension and that the mask for deep etching is removed by the fine grinding and that the ink nozzles are then etched. Method according to claim 8, characterized in that substantially photosensitized plate material is removed during the etching of the ink nozzles or that a third mask is applied before the etching. Process according to claims 1, 2, 4, 6, 7 and 9, characterized in that the production of the cavities, chambers and through holes takes place in parallel in one step after the areas to be removed on the plate material have been differently photosensitized, from which one Different etching speeds result in a separation into individual parts after the production of the required depth of the cavities and the chambers and the required thickness of the bottom layer (30) of the parts carrying the chambers, so that the ink nozzles are then etched into the parts carrying the chambers. Method according to claim 10, characterized in that the separating lines between the individual parts are also etched on the plate in the parallel plate processing process in order to facilitate subsequent separation. Method according to one of the preceding claims, characterized in that, after etching the ink nozzles, at least isolated plate parts, such as parts carrying chambers, middle parts are joined to form a module, after aligning the individual parts there being a stitching that the individual parts stitched together are permanently connected to one another and then a straight end edge by cutting off the nozzle tips and by fine grinding a flat surface of the end edge is created that by rinsing the cavities of the module with a first special liquid, a hydrophilic inner coating and by treating the surface of the end edge with a second special liquid, a hydrophobic outer coating, which subsequently be cured, arise. Method according to one of the preceding claims 1 to 12, characterized in that after the manufacture of the nozzles and the coating, the electrical conductor tracks and the piezo crystals are applied to the chamber base and / or to the outer surface of the base layer (30) and that contact is made. A method according to claim 13, characterized in that the piezocrystals are glued on and the adhesive connection is cured. A method according to claim 12, characterized in that the plate from which the individual parts are made consists of amorphous, photosenible glass, that the permanent connection of the individual parts to a module takes place by annealing, the temperature being selected so that a phase transition of amorphous to crystalline. A method according to claim 13, characterized in that the conductor tracks and / or a layer of piezoelectric material is applied by sputtering, that the piezoelectric layer is structured and contacted. Method according to one of the preceding claims 1 to 16, characterized in that individual modules are connected to one another via an at least one spacer to form an ink jet print head, or a multi-part module is used, and in that the ink jet print head is installed in a housing and making electrical connections. Method according to one of the preceding claims, characterized in that the spacer parts are produced from the plate material or from a layer of piezoelectric material applied to the surface of the plate, structuring being carried out by etching. Method according to one of the preceding claims, characterized in that the spacer parts are structured from the plate material in the parallel plate processing process before the separation. Method according to one of the preceding claims, characterized in that a nozzle cleaning by means of compressed air takes place after the completion of each module and / or after the completion of the print head. Method according to one of the preceding claims, characterized in that after completion of the print head, its functionality is tested and that faulty copies are discarded. A method according to claim 20, characterized in that during the parallel plate processing process or thereafter, electrical conductor tracks are applied to the middle parts in order to achieve a crossover-free line routing. Method according to one of the preceding claims 1 to 22, characterized in that the plate material consists of a photosensitive ceramic and / or a second plate material made of photosensitive, amorphous glass, that at least one individual part of a module is made of glass or ceramic material and that for connection the individual parts an adhesive connection is used.

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