EP2716459A1 - Ink jet writing head with sealing element - Google Patents

Abstract

The inkjet recording head (1) has a housing (2) comprising an ink pressure chamber (4) in which is ink is filled. An outlet opening (14) is arranged in front wall (6) of ink pressure chamber. A closing structure (20) is arranged to close the outlet opening. A sealing element (36) is arranged to enclose ink chamber section (28) of guide tube (26) protruded from ink pressure chamber. The tension elements (22) are partially guided in guide tube. A spring ring (60) is arranged in the region located radially outside of ink chamber section of guide tube.

Description

1. a) einer in einem Gehäuse angeordneten, mit Tinte unter Überdruck befüllbaren Tintenkammer, in der in einer Frontwand Austrittsöffnungen angeordnet sind,
2. b) jeweils an einer Innenseite der Frontwand anliegenden und jeweils eine Austrittsöffnung verschließende, in einer Längsrichtung der zugehörigen Austrittsöffnungen bewegbaren Schließkörpern,
3. c) Zugelementen, die jeweils mit einem Schließkörper verbunden sind und sich koaxial zur Längsrichtung der jeweils zugeordneten Austrittsöffnung und jeweils durch eine in einer Rückwand der Tintenkammer angeordnete Betätigungsöffnung hindurch erstrecken,
4. d) Führungsrohren, in denen die Zugelemente zumindest teilweise geführt sind,
5. e) Zugvorrichtungen, die jeweils mit einem der Zugelemente an seinem der Tintenkammer abgewandten Ende verbunden sind, und
6. f) Dichtungselementen, die jeweils eine Zugvorrichtung gegenüber der Tintenkammer derart abdichten, dass ein Kontakt der Tinte mit der Zugvorrichtung verhindert wird,

wobei die Zugelemente derart axial bewegbar sind, dass bei einer kurzzeitigen Betätigung der Zugvorrichtung der zugehörige Schließkörper von seiner Austrittsöffnung abgehoben wird und Tinte durch die Austrittsöffnung nach außen gelangt, jeweils ein Dichtungselement den in die Tintenkammer hineinragenden Bereich jeweils eines Zugelementes vollständig umschließt und die zugehörige Betätigungsöffnung gegenüber der Tintenkammer dichtend verschließt, wobei das Dichtungselement derart ausgeführt ist, dass es mit seinem freien Ende den Schließkörper für die Austrittsöffnung bildet und jeweils ein Dichtungselement jeweils einen Tintenkammerabschnitt eines Führungsrohres dichtend umschließt.The invention relates to an ink-jet recording head with

1. a) a arranged in a housing, can be filled with ink under pressure over-pressure ink chamber in which are arranged in a front wall outlet openings,
2. b) in each case adjacent to an inner side of the front wall and in each case an outlet opening closing, in a longitudinal direction of the associated outlet openings movable closing bodies,
3. c) tension members which are each connected to a closing body and extend coaxially to the longitudinal direction of the respectively associated outlet opening and in each case through an actuating opening arranged in a rear wall of the ink chamber,
4. d) guide tubes in which the tension elements are at least partially guided,
5. e) traction devices which are each connected to one of the tension elements at its end facing away from the ink chamber, and
6. f) sealing elements each sealing a pulling device with respect to the ink chamber such that contact of the ink with the pulling device is prevented,

wherein the tension members are axially movable so that upon a brief actuation of the pulling device of the associated closing body is lifted from its outlet opening and ink passes through the outlet opening to the outside, each a sealing element completely enclosing the ink chamber in the region each of a tension element and the associated actuating opening sealingly closed with respect to the ink chamber, wherein the sealing element is designed such that it forms with its free end the closing body for the outlet opening and in each case a sealing member each sealingly surrounds an ink chamber portion of a guide tube.

Such ink-jet recording heads are used particularly in large-format heads used. Preferably, they are used in matrix printers. The state of the art is still on EP 0 445 137 B1 and DE 36 25 067 A1 pointed.

A printhead of a matrix printer has a plurality of closely juxtaposed, closed by movable closing body expression openings or outlet openings. A matrix is understood to mean a two-dimensional or one-dimensional arrangement of a plurality of outlet openings.

The ink-jet recording heads are used in particular as writing heads for labeling or marking devices, with which a label on objects, such as goods, which are located on a conveyor belt, or packages is applied. In this case, the outlet openings of the write head are released in the short term by lifting the closing body, so that ink under pressure can be brought to the surface to be printed. For this purpose, each closing body associated tension elements are actuated by means of the controllable pulling device such that the desired label is created on the surface to be printed.

For an attractive or exact print image is a prerequisite that the individual outlet openings are arranged with minimal distance from each other. This is made more difficult because the traction devices, usually electromagnets, have larger dimensions and can not be arranged as close as the outlet openings side by side. Therefore, tension members of such a length are arranged between the closing bodies and the associated traction devices that the traction devices can be arranged in fanned out side by side. The drive movements of the traction devices are transmitted via the tension elements on the closing body, wherein the tension elements can be designed for example as tension cables or wires or as tie rods.

Since the ink in the ink chamber is under pressure, it is essential to provide pressure tight seals between the traction devices and the ink chamber.

In the EP 0 445 137 B1 are to protect the traction devices sealing elements disclosed, which are each disposed outside the ink chamber, between an actuating opening and the associated pull rod. As an actuating opening those openings are designated, through which the tension element is led out of the housing of the ink chamber. These so-called tie rod seals are deformable in the axial direction of the tension members designed as tie rods and firmly connected both to the actuating opening and to the pull rod. The Zugstang seals are designed frusto-conical, with the other end is sealingly attached to the edge of the actuating opening and the narrower end of the pull rod sealingly surrounds. Thus, ink may pass through the actuation openings into the spaces defined by the tie-rod seals. The ink is thus in contact with moving parts (pull rod). This is disadvantageous because ink often crystallizes out over time or components of the ink are precipitated or deposited. If not used for some time, the ink may also dry out. Mechanical movements can be influenced and possibly impaired by such deposits or by the dried out ink. In addition, an exchange of the Zugstangdichtungen is possible only with relatively high effort.

The in the DE 36 25 067 A1 are also outside the ink chamber, in which the ink chamber opposite end portion of guide tubes for the tension elements, here wire ropes, arranged. Preferably, the sealing elements are arranged in the vicinity of the respective pulling devices and designed, for example, as compared to the pulling device dense bellows. Thus, the pressurized ink from the ink chamber rises through the guide tubes to the bellows executed seal. Also in this construction, the traction cable to be moved is surrounded by ink, which is why caused here by crystallization or by other types of deposits caused adverse effects on the mechanically movable parts. The maintenance and repair, especially the replacement of the seals are also difficult and time consuming.

From the US 4,723,131 For example, a pull cord with a ram head attached thereto is known which presses on a diaphragm to control the ink ejection. The moving parts are sealed by this membrane against the ink chamber.

In the practical operation of the ink-jet recording head after EP 1 219 439 B1 It has been found that the seal between the ink chamber portion of the guide tube and the sealing element is unsatisfactory. The ink has a solvent. Depending on the product to be printed different solvents are used. Typical extinguishing agents are water, ethanol, acetone, MEK, etc. Water is used, for example, in foods. Depending on the solvent used, however, the sealing elements now shrink or widen. The solvent has an influence on the material of the sealing element. Usually, a rubber-like material is used for the sealing elements, for example EPDM. Other materials are NBR, fluororubber or other suitable elastomers. With water and ethanol such rubber-like materials shrink, with acetone and MEK they expand. They become loose, the plastic becomes so soft that the connection between the ink chamber section of the guide tube and the sealing element is no longer present. It comes to leaks, it also comes to a reduced hold of the sealing element at the ink chamber portion and an unwanted relative movement between the two. This leads to a significantly increased wear, the sealing elements must be replaced earlier than intended. All this is disadvantageous.

This is where the invention begins. It has set itself the task of reducing the influence of different solvents on the function of the sealing elements to improve the tightness between the sealing element and the ink chamber portion and make it more durable than before and to ensure that the sealing element does not move in practical operation as possible along the ink chamber portion ,

The ink-jet recording head should have the highest possible technical life and the production and maintenance should be as simple and inexpensive as possible.

This object is achieved by the features of claim 1.

By the spring ring, the sealing element is active and constantly against the Ink chamber portion of the guide tube pressed. While previously, in the prior art, only the elastic effect of the material of the sealing element has been used, now presses the spring ring, the sealing element radially inwardly and presses it into abutment against the ink chamber portion of the guide tube. As a result, the seal is significantly improved. The seal is still guaranteed even if the material of the sealing element is softened by the solvent or expands. The function of the ink jet recording head is now essentially independent of the particular solvent used.

The spring ring should have more than one turn. This is to be understood that the spring ring extends over more than 360 °. Preferably, it has 1.5 to 3.5 turns, in particular 2.5 turns. It thus revolves around the sealing element to at least 540 °, a rounding to 900 ° is preferred. The spring ring is preferably made of a round wire material, then the turns are next to each other. In another, preferred embodiment of the spring ring is made of flat, band-shaped material, then the turns are preferably one above the other. The spring ring engages around the sealing element in the region of the ink chamber portion of the guide tube from the outside. In other words, the sealing member is located between the spring ring and the ink chamber portion.

Preferably, the spring ring is in a range between 1/4 and 3/4 of the axial length of the ink chamber portion. In particular, the spring ring is arranged approximately on the longitudinal center of the ink chamber portion.

As advantageous, an annular, circumferential indentation in the outer jacket of the sealing element has been shown. It can also be called a groove or a throat. It is chosen so large that the spring washer is located inside the indentation. It does not protrude radially beyond the outer jacket of the sealing element. Overall, this does not contribute to the spring ring, he claimed over the previously known construction not extra space. This means that even old inkjet printheads after the EP 1 219 439 B1 can be converted to the present invention, so can be provided with a spring ring.

As before, the sealing members are disposed within the ink chamber and sealingly enclose the portions of the tension members protruding into the ink chamber, thereby preventing ink from contacting moving parts.
The arrangement of the sealing elements within the ink chamber advantageously causes the ink pressure or with about 1 bar to about 10 bar, typically 0.25 to 0.5 bar, under pressure over standing ink sealingly acts on the sealing elements, since these against the guide tubes or pressed in the direction of the actuating openings. Thus, in contrast to the known embodiments, the pressure within the ink chamber with a constant or even increasing sealing effect of the sealing elements can also be significantly increased (for example, up to 10 bar). One of the reasons why a high pressure is preferable is that the types of inks used are often highly viscous liquids.

The sealing elements with their spring ring are attached to the already built into the inkjet print head ink chamber sections of the guide tubes, so that replacement of defective sealing elements can be done quickly and easily. Alternatively, the spring rings can be applied to the already attached to the ink chamber sections sealing elements. It is advantageous if the front wall of the ink chamber is removable from the outside.

In principle, the sealing elements fulfill three independent tasks. Each of the associated actuating opening facing portion causes the sealing of the ink chamber, the underlying central region acts as a deformable bellows and the each of the associated outlet opening facing portion causes the closing function. Because the closing bodies are formed by the sealing elements themselves and because the sealing elements consist of an elastic, rubber-like material, the sealing of the outlet openings is reliably ensured and higher manufacturing tolerances can be accepted with regard to the length of the sealing elements. For a complete seal of the ink chamber with respect to the actuating openings satisfy due to the bag-like formation of the Sealing members only the sealing, the ink chamber portion of the guide tube enclosing portion. The sealing elements are integral.

Furthermore, it has been shown that it is advantageous if the guide tubes also protrude outside the ink chamber with respect to the rear wall. The above section has the advantage that the dirt and deposits which inevitably arise outside the ink chamber and which preferably deposit on the rear wall are difficult to penetrate into the actuating openings.

The sealing of the ink chamber against externally penetrating contaminants can additionally be improved by closing the sections of the guide tubes arranged outside the ink chamber with additional sealing means. For example, sealing elements designed as capillary tubes can be pushed onto the protruding sections of the guide tubes, so that they tightly surround these and also the pull rod.

Lubrication of the tension elements can additionally be achieved by additionally applying an oil to the openings of the guide tubes arranged outside the ink chamber.

The inventive ink jet recording head has an extremely low susceptibility to interference, since the sealing of the sealing elements with respect to the ink chamber sections and the mechanical support of the sealing elements on the ink chamber sections are now significantly improved. The ink chamber is sealed against external contamination. The ink can not reach the area of the moving parts. The inkjet printhead is very small in size and is quick and efficient to service and repair since the sealing elements can be easily replaced after the ink chamber has been previously opened.

Fig. 1:

eine Ausschnittsvergrößerung eines erfindungsgemäßen TintenstrahlSchreibkopfes im Schnitt, wobei der Übersicht halber die Systemkomponenten Zugstange, Führungsrohr und Dichtungselement nur einmal dargestellt sind,

Fig. 2:

eine Ausschnittsvergrößerung einer weiteren Ausführungsvariante des erfindungsemäßen Tintenstrahl-Schreibkopfes im Schnitt gemäß Fig. 1,

Fig. 3:

ein axiales Schnittbild durch eine Anordnung aus einem Dichtungselement und einem Federring, wobei der Federring mehrere, radial übereinander liegende Windungen aufweist, und

Fig. 4:

eine vergrößerte Darstellung eines Dichtungselementes und eines Federrings, wie Fig. 3.

Further advantageous design features of the article according to the invention are contained in the description of the figures and in the subclaims. Based on the following figures, the invention will be explained in more detail. The embodiments shown are not intended to be limiting. Show it:

Fig. 1:

an enlarged detail of an ink jet recording head according to the invention in section, wherein the sake of clarity, the system components tie rod, guide tube and sealing element are shown only once,

Fig. 2:

an enlarged detail of another embodiment of the inventive ink jet recording head in section according to Fig. 1 .

3:

an axial sectional view through an arrangement of a sealing element and a spring ring, wherein the spring ring has a plurality of radially superimposed turns, and

4:

an enlarged view of a sealing element and a spring ring, such as Fig. 3 ,

An ink jet recording head 1 according to the invention has an ink chamber 4 arranged in a housing 2. The substantially cubic ink chamber 4 is bounded by a front wall 6, side walls 8 and a rear wall 10. The front wall 6 is preferably detachably connected to the housing 2 and sealed by a preferably formed as an O-ring 12 seal. In the front wall 6 outlet openings 14 are arranged, which act as a nozzle for exiting during the printing process ink 16. The term ink 16 means all suitable for labeling and marking substances such as paints, acids, etc. The area surrounding the outlet openings 14 is curved in the direction of the ink chamber 4, wherein the outlet openings 14 are arranged in the center of the curvature 18. The vault 18 has a twofold beneficial effect. First, the outlet openings 14 are extended in the direction of their longitudinal axes XX, whereby a better management of the exiting ink drops is achieved, which in turn requires a more accurate printed image. On the other hand, directed in the direction of the ink chamber 4 bulges 18 lead to a better sealing of the outlet openings 14 through The discharge openings 14 abutting closing body 20. The voltage applied to the outlet openings 14 surfaces of the closing body 20 are designed substantially flat. In principle, the voltage applied to the outlet openings 14 surfaces of the closing body 20 may also be curved. It is also possible both bearing surfaces, the closing body 20 and the area around the outlet openings 14) to execute plan.

Each closing body 20 is a tension element 22, preferably associated with a pull rod which extends coaxially to the longitudinal axis X-X of the respective outlet opening 14. Instead of tie rods, it is also possible to use pull ropes or similar tension elements. The tension elements 22 extend through actuating openings 24 arranged in the rear wall 10 and are connected to pulling devices (not shown). Advantageously, the tension elements 22 may have a diameter of, for example, 1 to 1.2 mm and be designed as hollow pull tubes, in order thus to achieve a material and thus a weight reduction. As pulling devices in particular electromagnets are suitable, which accomplish a stroke of the closing body 20 of, for example, about 0.2 mm.

According to the invention, guide tubes 26 extending coaxially with the tension elements 22 are arranged in the actuation openings 24 and have both an ink chamber section 28 protruding into the ink chamber 4 and an outer section 30 protruding outside the ink chamber 4 opposite the housing 2. The tension elements 22 are guided in the guide tubes 26. The ink 16 passes through a bore 32 from an ink tank, not shown, the terminal end 34 is connected to the arranged in one of the side walls 8 bore 32, under pressure into the ink chamber. 4

According to the invention, the actuating openings 24 are each sealed off from the ink 16 in the ink chamber 4 by a sealing element 36. Advantageously, the sealing elements 36 enclose the regions of the tension elements 22 projecting into the ink chamber 4. In the illustrated embodiment, the sealing elements 36 not only surround the tension elements 22 but also the ink chamber sections 28 of the guide tubes 26, thus sealing the actuating openings 24 securely.

Advantageously, the sealing elements 36 can be easily pushed onto the tension elements 22 and ink chamber sections 28. In order to ensure a secure fit on the tension elements 22 and the guide tubes 26, the tension elements 22 in their outlet openings 14 facing end regions each have an annular, transversely to the longitudinal axis X-X extending groove 38 in which the respective sealing member 36 comes to rest.

A particular advantage of the embodiment of the sealing elements 36 according to the invention lies in the fact that they themselves act directly as a closing body 20, since the sealing elements 36 consisting of an elastic rubber-like material rest against the outlet openings 14. Additional closing body elements omitted.

Because of the different requirements for the ink 16, the types of material which are suitable for the production of the sealing elements 36 must also be adapted accordingly.

FIG. 1 shows a first embodiment of the sealing element according to the invention 36. This is designed substantially cylindrical and has a thinned wall portion 40 in the middle. This wall section 40 facilitates the deformation of the sealing element 36 when the pulling device is actuated or when the closing element 20 is lifted off the outlet opening 14 for a short time. The wall section 40 can then preferably deform inwards.

FIG. 2 shows an advantageous further embodiment variant of the sealing element according to the invention 36. This has starting from the voltage applied to the outlet opening 14 a frustoconical portion 42 which merges into a substantially cylindrical portion 44. The execution of the truncated cone-like portion 42 results in that the pressurized ink is directed towards the outlet opening 14. As a result, high printing speeds and a precise print image can be realized. The overpressure in the ink chamber is for example 1 bar, whereby turbulences of the ink 16 are minimized.

Furthermore, it has also proved to be advantageous if the sealing element 36 in the region between the outlet opening 14 and near the end of the ink chamber portion 28 of the guide tube 26, a constriction 46 instead of in Fig. 1 has shown diluted wall portion 40. The constriction 46 causes, upon actuation of the tension elements 22, a defined widening of the area of the sealing element 36 that is limited by the constriction 46 and that of the actuating opening 24. By this relatively long portion a gentle deformation of the sealing element 36 is achieved, which in turn the durability of the sealing element 36 is significantly extended.

The technical life of the inkjet recording head 1 can be further extended by the fact that penetration of dirt particles or deposits through the actuating openings 24 in the region of the tension elements 22 is avoided by closing means. This can essentially be achieved by additionally closing the outer sections 30 of the guide tubes 26 with sealing means 50. These are advantageously tubular and consist of an elastic material, preferably the material from which the sealing elements 36 are made. The sealing means 50, in particular capillary tubes, are pushed onto the tension elements 22 or onto the outer sections of the guide tubes 26 and enclose them. Due to their elasticity, the sealing means 50 do not hinder the movement of the tension elements 22.

Furthermore, the actuating openings 24 and the corresponding ends of the guide tubes 26 are acted upon by an oil 48 in order to achieve a lubrication of the tension elements 20.

As in Fig. 1 and 3 is shown, the sealing element 36 is encompassed in its upper region, namely in the region which is located radially outside of the ink chamber portion 28 of the associated guide tube 26, by a spring ring 60. This is in the two embodiments of the FIGS. 1 and 3 each made of a round wire, which has several turns. The turns are axially adjacent. Formed is a cylindrical Spring, also called coil spring. The ink chamber portion 28 extends in the axial direction over a length L.

The two versions after the FIGS. 1 and 3 differ in that the sealing element 36 after Fig. 3 an annular indentation 62, that after Fig. 1 but not. The indentation 62 is located approximately at the longitudinal center of the ink chamber section 28 in the assembled state of the sealing element 36. The radial depth of the indentation 62 is selected to be greater than the radial thickness of the spring ring 60, in particular as the diameter of the wire from which the spring ring 60 is made. The indentation 62 has a U-shape in cross-section, with the inner corners being rounded. It can be seen that the material thickness of the sealing element 36 in the region of the indentation 62 is reduced to a maximum of 50% of the material thickness in the axially immediately adjacent region. A reduction beyond 50% is possible.

The axial length of the indentation 62 is 10 to 50% greater than the axial length of the spring ring 60th

Preferably, the ends of the spring ring 60 are rounded or slightly bent away to the outside, so that the ends can not dig into the material of the sealing element 36. The spring ring 60 should not mechanically injure the sealing element 36.

The two versions after the Figures 2 and 4 differ from the explanations just discussed after the FIGS. 1 and 3 in that now instead of a spring ring 60 with juxtaposed windings, a spring ring 60 is inserted, which has superposed turns. It is made of a flat, band-shaped spring material. The width of the material determines the axial extent of the spring ring 60. There are several turns one above the other, there are about 2.5 turns provided. Again, it is recommended that the edges and in particular the inner end of the spring ring 60 to edit, in particular deburring that the spring ring 60 does not cut into the material of the sealing element 36 and can injure the sealing material. Again shows Fig. 4 a dent 62 as in Fig. 3 , the Fig. 2 shows like that Fig. 1 no such indentation.

In practical implementation, the discussed parts, in particular the sealing element 36 and the spring ring 60, are relatively small. The outer diameter of both lies in the range between 1 and 3 mm. For the spring ring made of wire, for example, wire with a diameter of 0.1 to 0.3 mm, in particular 0.15 mm is used. For the spring washers made of band-shaped material FIG. 2 or FIG. 4 a cross section of the strip material of 0.01 to 0.08 mm thickness and 0.5 to 1 mm axial length is used.

Preferably, sealing means are respectively arranged between the outer sections of the guide tubes and the tension elements, which sealingly surround both the outer sections and the pull rod.

Closing means are preferably arranged on the ends of the actuating openings facing away from the ink chamber.

The invention is not limited to the illustrated and described embodiments, but also includes all the same in the context of the invention embodiments according to claim 1.

LIST OF REFERENCE NUMBERS

1

Inkjet Stylus

2

casing

4

ink chamber

6

front wall

8th

side walls

10

rear wall

12

O-ring

14

outlet opening

16

ink

18

bulge

20

closing body

22

tension elements

24

confirmation opening

26

guide tubes

28

Ink chamber section

30

outer portion

32

drilling

34

terminal end

36

sealing element

40

wall section

42

frusto-conical section

44

cylindrical section

46

constriction

48

oil

50

sealant

60

spring washer

62

indentation

Claims (9)

Inkjet recording head (1) with a) arranged in a housing (2), with ink (16) can be filled under pressure over the ink chamber (4) in which in a front wall (6) outlet openings (14) are arranged, b) in each case on an inner side of the front wall (6) adjacent and in each case an outlet opening (14) closing, in a longitudinal direction (XX) of the associated outlet openings (14) movable closing bodies (20), g) tension elements (22) which are each connected to a closing body (20) and are coaxial with the longitudinal direction (XX) of the respective associated outlet opening (14) and in each case by a rear wall (10) of the ink chamber (4) arranged actuating opening ( 24) extend through, h) guide tubes (26) in which the tension elements (22) are at least partially guided, i) traction devices which are each connected to one of the tension elements (22) at its end remote from the ink chamber (4), and j) sealing elements (36) each sealing a pulling device with respect to the ink chamber (4) such that contact of the ink (16) with the pulling device is prevented,
wherein the tension elements (22) are axially movable in such a way that the associated closing body (20) is lifted off its outlet opening (14) during a brief actuation of the pulling device and ink (16) passes through the outlet opening (14) to the outside, the guide tubes ( 26) have an ink chamber portion (28) projecting into the ink chamber (4), and each seal member (36) completely encloses an ink chamber portion (28) projecting into the ink chamber (4), the seal member (36) being made to mate with its free end forms the closing body (20) for the outlet opening (14), characterized in that a spring ring (60) is provided which more than a winding, wherein the windings are arranged either side by side or one above the other, and that the spring ring (60) engages around the sealing element (36) in the region of the ink chamber portion (28) on the outside. An ink-jet recording head (1) according to claim 1, characterized in that the spring ring (60) is located in a section of 1/4 to 3/4 of the axial length (L) of the ink chamber portion (28), preferably half of the axial one Length is. Ink-jet recording head (1) according to one of the preceding claims, characterized in that the spring ring (60) has a maximum of four turns, in particular a maximum of three turns. Ink-jet recording head (1), according to one of the preceding claims, characterized in that the sealing element (36) has an annular circumferential indentation (62) within which the spring ring (60) is located in the mounted state. An ink jet recording head (1) according to claim 4, characterized in that the annular recess (62) to the outside is open. An ink jet recording head (1) according to any one of claims 4 or 5, characterized in that the annular recess (62) has an axial length 10 to 50% greater than the axial length of the spring ring (60). An ink jet recording head (1) according to any one of claims 4 to 6, characterized in that the annular recess (62) has a radial depth which is at least 10% greater than the radial thickness of the spring ring (60). Ink jet recording head (1) according to one of claims 4 to 7, characterized in that the indentation (62) has rounded inner corners. An ink-jet recording head (1) according to any one of the preceding claims, characterized in that the ends of the spring material of the spring ring (60) which come into contact with the sealing member (36) are rounded or bent.

Images