CERAMIC HYDRAULIC DISTRIBUTOR FOR AN INK-JET PRINTER

Abstract

 The invention concerns a hydraulic distributor for an ink-jet printer, comprising:
- a first portion (2), comprising at least one 1^st planar surface (4), a second portion (8, 108), comprising at least one 2^nd planar surface (10), both planar surfaces being in friction contact with each other;
- at least one 1^st conduct (6) in said 1^st portion, each comprising a 1^st opening in said 1^st planar surface;
- at least one channel (12) extending in said second portion (8, 108), to conduct a fluid in a direction substantially parallel to said 2^nd planar surface;
- at least one 2^nd conduct in one of said portions, comprising a 2^nd opening in said 1^st planar surface or in said 2^nd planar surface or in said at least one channel;
- means for moving both portions with respect to each other.

Description

TECHNICAL DOMAIN AND PRIOR ART

[0001] The invention relates to the domain of industrial inkjet printers, for example continuous inkjet (CIJ) printers.

[0002] In particular, it relates to a hydraulic distributor for such a printer and to an ink circuit of such a printer.

[0003] Typically, a fluid supply circuit of an ink jet printer comprises several valves, such as solenoid valves or electro-valves. A solenoid valve is an expensive and complex device; as a result, it can be inoperative or have faults which are difficult to identify and/or to repair. Furthermore, the pressure loss between the input and the output of such a valve is important.

[0004] CIJ printers include solenoid valves for large ink flows, but they are bulky, heavy and expensive.

[0005] There is thus a need for a fluid distributor to replace such valves in an ink circuit of an ink jet printer, in particular of a continuous ink jet printer for which the ink flow rates are quite important.

PRESENTATION OF THE INVENTION

[0006] A first object or purpose of the invention is a hydraulic distributor for an ink-jet printer, comprising:

• a first portion, comprising at least one 1^st planar surface, for example in a glass or ceramic material or in stainless steel, a second portion, comprising at least one 2^nd planar surface, for example in a glass or ceramic material or in stainless steel, both planar surfaces being in friction contact with each other;
• at least one 1^st duct or conduct in said 1^st portion, comprising a 1^st opening in said 1^st planar surface;
• at least 2^nd one duct or through duct, to guide or conduct a fluid in a direction substantially perpendicular to said 2^nd planar surface or to said 1^st planar surface and/or at least one channel extending in said second portion, for example at least partly in said 2^nd planar surface, to guide or conduct a fluid in a direction substantially parallel to said 2^nd planar surface or to said 1^st planar surface.

[0007] Said at least one 2^nd conduct can be in one of said portions and comprises a 2^nd opening in said 1^st planar surface or in said 2^nd planar surface or in said at least one channel.

[0008] A hydraulic distributor according to the invention preferably further comprises means for moving both portions with respect to each other, so that:

* in a first position, at least the 1^st opening or the 1^st duct or conduct and the 2^nd opening or the 2^nd duct or conduct are directly connected to each other (and a fluid can flow directly from one of them to the other one), or at least both the 1^st opening (or the 1^st duct or conduct) and the 2^nd opening (or the 2^nd duct or conduct) open in said at least one channel and are connected through said at least one channel (and a fluid can flow from one of them to said at least one channel and then to the other duct or conduct);

* and, in a second position, said 1^st opening or 1^st duct or conduct and said 2^nd opening or 2^nd duct or conduct are not connected to each other (and no fluid can flow from one of them to the other one), or at least one of said 1^st opening (or 1^st duct or conduct) and said 2^nd opening (or 2^nd duct or conduct) does not open in said at least one channel, and the openings or ducts or conducts are not connected through said at least one channel (and no fluid can flow from one of them to said at least one channel and then to the other duct or conduct).

[0009] A hydraulic distributor according to the invention can have more than 2 2 openings or ducts or conducts, so that in one or more relative position(s) of both portions more than 2 openings or ducts or conducts can be connected together, possibly through a channel in order to guide or conduct a fluid partly in a direction substantially parallel to said 2^nd planar surface or said 1^st planar surface, and fluid can flow from at least one opening or duct or conduct to at least two other openings or ducts or conducts or from at least 2 openings or ducts or conducts to at least one or more of them.

[0010] A hydraulic distributor according to the invention does not make use of any gaskets and is thus more robust than solenoid valves or electro-valves.

[0011] In an embodiment, said hydraulic distributor comprises at least one channel extending in said second portion, for example at least partly in said 2^nd planar surface, to guide or conduct a fluid in a direction substantially parallel to said 2^nd planar surface or to said 1^st planar surface, and:

* in a first position, at least both the 1^st opening (or the 1^st duct or conduct) and the 2^nd opening (or the 2^nd duct or conduct) open in said at least one channel and are connected through said at least one channel, and a fluid can flow from one of them, to or through said at least one channel and then to the other opening or duct or conduct;

* and, in a second position, at least one of said 1^st opening (or 1^st duct or conduct) and said 2^nd opening (or 2^nd duct or conduct) does not open in said at least one channel, and said openings are not connected through said at least one channel, and no fluid can flow from one of them to said at least one channel and then to the other duct or conduct.

[0012] In another embodiment, said hydraulic distributor comprises at least one at least one 2^nd conduct in said 2^nd portion, comprising a 2^nd opening in said 2^nd planar surface and:

* in a first position, the 1^st opening or the 1^st duct or conduct and the 2^nd opening or the 2^nd duct or conduct are directly connected to each other (and a fluid can flow from one of them directly to the other one);

* and, in a second position, said 1^st opening or 1^st duct or conduct and said 2^nd opening or 2^nd duct or conduct are not connected to each other (and no fluid can flow from one of them to the other one).

[0013] In an embodiment of a hydraulic distributor according to the invention, said means for moving both portions with respect to each other are able to move at least one of said portions circularly around an axis perpendicular to both said 1^st planar surface and said 2^nd planar surface.

[0014] For example, said means may comprise a rotating shaft, which extends along said axis.

[0015] One end of said shaft being inserted in a hole in said 2^nd portion.

[0016] Each of said shaft and said hole may comprise a flat surface which extends parallel to said axis and which cooperate which each other to rotate both said shaft and said 2^nd portion.

[0017] In another embodiment of a hydraulic distributor according to the invention, said means for moving both portions with respect to each other are able to move at least one of said portions in translation along an axis parallel to both said 1^st planar surface and said 2^nd planar surface.

[0018] In any of the embodiments of a hydraulic distributor according to the invention, a hydraulic distributor according to the invention can further comprises means, for example a spring, for pressing said 1^st planar surface and said 2^nd planar surface against each other.

[0019] In a hydraulic distributor according to the invention:

• said 1^st portion can comprise at least 2 or 3 conducts, each comprising an opening in said 1^st planar surface;
• said 2^nd portion can comprise at least one channel, to guide or conduct a fluid in a direction substantially parallel to said 2^nd planar surface or to said 1^st planar surface, and at least one conduct or 2^nd conduct, to guide or conduct a fluid in a direction substantially perpendicular to said 2^nd planar surface or to said 1^st planar surface, said 2^nd conduct comprising an opening in said channel;
• and/or said 1^st planar surface and said 2^nd planar surface can comprise a glass material or a ceramic material or in stainless steel;
• and/or said 1^st planar surface and said 2^nd planar surface have a roughness of between 0,4 µm and 0,8 µm.

[0020] In any embodiment of a hydraulic distributor according to the invention, said 1^st portion can comprise at least 3 conducts, each comprising an opening in said 1^st planar surface, so that said channel, which guides or conducts a fluid in a direction substantially parallel to said 2^nd planar surface or to said 1^st planar surface, connects:

• in said first position, at least a first pair of said at least 3 conducts;
• and, in said second position, another at least another pair of said at least 3 conducts.

[0021] A hydraulic distributor according to the invention can comprise a plurality of channels extending in said 2^nd portion, or at least partly in said 2^nd planar surface, to conduct a fluid in at least two different directions substantially parallel to said 2^nd planar surface.

[0022] In a hydraulic distributor according to the invention, said means for moving both portions with respect to each other can comprise a motor, for example an electric or hydraulic or pneumatic motor.

[0023] The invention also concerns an ink jet printer comprising a print head and an ink supply circuit, said ink supply circuit comprising at least one hydraulic distributor according to the invention.

[0024] The invention also concerns a method for operating an inkjet printer according to the invention, in particular according to at least one of the embodiments described above or in this application.

[0025] Said method can comprise moving both portions of said at least one hydraulic distributor with respect to each other between said first positions and said second position, so that:

* in said first position, at least both the 1^st opening (or the 1^st duct or conduct) and the 2^nd opening (or the 2^nd duct or conduct) are connected together or open in at least one channel and a fluid, for example ink and/or solvent, flows from one of said opening to the other of said openings, possibly at least partly through at least one of said channel(s) in a direction substantially parallel to said 2^nd planar surface or said 1^st planar su rface;

* and, in said second position, at least one of said 1^st opening and 2^nd opening are not connected together or does not open in said at least one channel, and no fluid can flow from one opening or duct or conduct to the other one.

[0026] Or said method can comprise moving both portions of said at least one hydraulic distributor with respect to each other between said first positions and said second position, so that:

* in a first position, the 1^st opening or the 1^st duct or conduct and the 2^nd opening or the 2^nd duct or conduct are directly connected to each other, and a fluid can flow from one of them directly to the other one;

* and, in a second position, said 1^st opening or 1^st duct or conduct and said 2^nd opening or 2^nd duct or conduct are not connected to each other, and no fluid can flow from one of them to the other one.

BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Example embodiments of the invention will now be described with reference to the appended drawings among which:

Figures 1A and 1B represent different views of a hydraulic distributor according to the invention;

Figures 1C and 1D show another embodiment of a hydraulic distributor according to the invention;

Figure 1E shows an embodiment inserted in a guiding cylinder.

Figures 2A and 2B show further details of a hydraulic distributor according to the invention.

Figures 3A and 3B show two positions of a hydraulic distributor according to the invention.

Figure 4 shows an example of a hydraulic distributor according to the invention, forming a shutter;

Figures 5A and 5B show another example of a hydraulic distributor according to the invention, comprising 6 ducts and 2 connecting channels;

Figures 6A - 9B show different relative positions of the two portions of a hydraulic distributor according to the invention;

Figures 10A and 10B show an example of a linear hydraulic distributor according to the invention.

Figure 10C shows an example of a linear hydraulic distributor in a guiding structure.

Figures 11A and 11B represent different views of two parts of a portion of a hydraulic distributor according to the invention, assembled to form an inside channel.

Figure 12 shows an embodiment wherein the second portion includes two inside channels.

Figures 13A and 13B represent different views of another embodiment of a hydraulic distributor according to the invention, wherein the second portion includes through ducts.

Figures 14A - 14B represent assembling steps of a hydraulic distributor according to the invention.

Figure 14C represents a hydraulic distributor according to the invention assembled in a body of a printer.

[0028] Similar or identical technical elements are designated by the same reference numbers on the different figures.

DETAILED PRESENTATION OF EMBODIMENTS OF THE INVENTION.

[0029] A first example of an embodiment of a hydraulic distributor according to the invention is illustrated on figures 1A-2B.

[0030] It comprises:

• A first portion 2, which has a flat surface 4 and which comprises 3 though conducts or ducts 6 which open in said surface 4;
• A second portion 8, which has a flat surface 10 and which comprises a channel 12 (figure 1B) which extends in said surface 10.

[0031] When the device is assembled, both flat surfaces 4, 10 are in friction contact with each other: they can be rotated relative to each other but remain in contact during the rotation. No fluid can flow out of the device between both surfaces: the contact at the interface between both surfaces is watertight. A device according to the invention does not require any gasket.

[0032] Means 30, such as a spring, can be used to press both surfaces against each other.

[0033] The first portion rests on a support 11 on which it can be maintained in a fixed position; each of the first portion and the support can comprise means 13 (figure 2B), 14 (figure 1B) which cooperate with each other to keep the first portion in a fixed position.

[0034] In this example both portions 2, 8 have a cylindrical shape, but other shapes are possible, as described below in connection with figures 10A-10C.

[0035] In an embodiment, the hydraulic distributor comprises a shaft 20 which extends along an axis of rotation to rotate portion 8 with respect to portion 2.

[0036] A handle 27 is represented on figures 2A and 2B to manually control said shaft. Alternatively, said shaft can be controlled by a motor (as explained below in connection with figures 14A-14C), which itself can be controlled by the controller of a printer.

[0037] A cover 25 can cover the two portions (figure 2B): one end of the shaft 20 rises above the top surface of the cover so that it can be connected to a handle 27 or to any transmission mechanism from a motor.

[0038] Figures 1C and 1D show a variant of figure 1A and 1B. Like on figures 1A and 1B:

• the first portion 2 comprises 3 though conducts or ducts 6 which open in the surface 4;
• the second portion 8 comprises a channel 12 which extends in surface 10.

[0039] In this embodiment, the surface of the second portion opposed to surface 10 comprises several holes 21 which can accommodate studs of a tool or of a driving section (see figures 14A-14B), to rotate the second portion 8 with respect to the first portion 2. Thus, a central shaft which traverses through the second portion is not needed.

[0040] Both first and second portions can be guided in rotation in a guiding cylinder 37, as illustrated on figure 1E, fluid entering the distributor through one of said ducts 6, then flowing along said channel 12 and leaving the distributor through another one of said ducts 6.

[0041] Another example of portions guided in rotation is illustrated on figures 14A-14C and commented below.

[0042] As illustrated on figure 1E, the hydraulic distributor of figures 1C and 1D can be inserted in guiding cylinder 37, which guides both portions 2, 8 with respect to each other, portion 2 being maintained fixed with help of means (like means 13, 14 described above) not illustrated on the figure.

[0043] The arrows show how the fluid flows into the distributor through duct 6₁, then flows in or through the channel 12 and flows out of the distributor through duct 6₂. In a variant (not represented on figure 1E), the portion 2 has 3 through ducts, which are connected together in a certain relative position of both portions 2, 8.

[0044] Figures 3A and 3B show surface 4 of the first portion (which comprises 3 through ducts 6₁ - 6₃) and surface 10 of the second portion (which comprises one channel 12); as illustrated on figures 3A and 3B (on which hole 14 is not represented):

* in a first position (figure 3A), a first pair of ducts 6₁, 6₂ open in said channel 12; a 1^st fluid can circulate from duct 6₁ to duct 6₂ (or from one duct of said first pair of ducts to the other duct) through said channel 12; no fluid can circulate from duct 6₁ to duct 6₃;

* and, in a second position (figure 3B), a second pair of ducts 6₁, 6₃ open in said channel 12; a 2^nd fluid can circulate from duct 6₁ to duct 6₃ (or from of one duct of said second pair of ducts to the other duct) through said channel 12, but the 1^st fluid can no longer circulate from duct 6₁ to duct 6₂.

[0045] In any embodiment of a device according to the invention, a spring 30 can be used to press said first portion 2 against said second portion 8.

[0046] Fig.4 shows a simpler example of a hydraulic distributor (actually a hydraulic shutter) according to the invention, the first portion 2 comprising two through ducts 6₁, 6₂ and the 2^nd portion 6 having one channel 12. In a first position of the 2^nd portion, the channel 12 connects both ducts 6₁, 6₂ and the fluid can circulate from one of said ducts to the other one. In a second position (not represented) of the 2^nd portion, the channel 12 does not connect ducts 6₁, 6₂ together and the fluid circulation is stopped.

[0047] Fig. 5A and 5B show an example of a hydraulic distributor according to the invention, the first portion 2 comprising 6 through ducts 6₁ - 6₆ and the 2^nd portion 8 having 2 channels 12₁, 12₂.

[0048] Figure 6A (resp.7A, 8A, 9A) shows the surface 10' of the second portion 8 opposed to surface 10; this surface 18 comprises several holes 21 as explained above to drive the second portion with respect to the first portion.

[0049] Figure 6B (resp.7A, 8A, 9A) shows the surface 10 of the second portion 8 which comprises the 2 channels 12₁, 12₂.

[0050] 4 different relative positions of the both portions are illustrated on figures 6A-9B to connect different pairs or series of through ducts 6₁ - 6₆.; figures 6B, 7B, 8B, 9B show the different positions of the 2 channels 12₁, 12₂ and the projection on surface 10 of the positions of the ducts 6₁ - 6₆:

• in figures 6A and 6B, channel 12₂ connects through ducts 6₃ and 6₆ and channel 12₁ connects through ducts 6₂ and 6₁;
• in figures 7A and 7B, channel 12₁ connects through ducts 6₁, 6₅ and 6₄ (thus allowing flow from one of said 3 ducts 6₁, 6₅ and 6₄ to the two other ducts or a flow from two of said ducts to the third one) and channel 12₂ connects through ducts 6₂ and 6₆;
• in figures 8A and 8B, channel 12₁ connects through ducts 6₃ and 6₄ and channel 12₂ connects through ducts 6₁, 6₅ and 6₆ (thus allowing flow from one of said 3 ducts 6₁, 6₅ and 6₆ to the two other ducts or a flow from two of said ducts to the third one);
• in figures 9A and 9B, channel 12₁ connects through ducts 6₃ and 6₂ and channel 12₂ connects through ducts 6₄ and 6₆.

[0051] The above example of Fig. 5A and 5B, and those of figures 7A-B and 8A-B, shows that, in one or more relative position of both portions, a hydraulic distributor according to the invention can connect more than two ducts together.

[0052] A linear hydraulic distributor according to the invention is disclosed in connection with fig.10A-11; like the circular device disclosed above, it can have any number of through ducts 6, and any number of appropriate channels to establish the required connections between the through ducts in the different relative positions of the two portions 2, 8.

[0053] As illustrated on figures 10A and 10B, a linear hydraulic distributor according to the invention implements a relative translation of the 2 portions rather than a rotation.

[0054] Both portions can be maintained by lateral guiding walls 47 guiding the translation of one portion of said hydraulic distributor with respect to the other; this translation can be actuated by an actuating link or a button or by a motor, for example an electric or hydraulic or pneumatic motor, coupled to one of the portions 108, 102

[0055] A spring can be used between one of the guiding walls, parallel to the direction of the translation to press said both portions of said hydraulic distributor against each other.

[0056] In the above examples:

• both portions are preferably made of a glass material (which can be polished) or a ceramic material; one example of such material is alumina (Al₂O₃) but other ceramic materials are possible; another example of material is stainless steel (which can also be polished);
• and/or the surfaces 4, 10 (resp.104, 110) have a roughness between 0,4 and 0,8 µm, which favours the water tightness of the system.

[0057] In the above examples, a channel 12 opens at least partly or is at least partly comprised in the surface 10. In another embodiment, said channel is made inside said 2^nd portion and does not appear in the surface 10 of said 2^nd portion.

[0058] Figures 11A and11B shows an example of a second portion made by assembling two parts 8₁, 8₂, to form an inside channel 12a, which can be connected to any of the main surfaces 10, 10' by one or more ducts 121, 122 which extend substantially perpendicularly to said surfaces 10, 10'. In certain positions of the two portions 2, 8b Both ducts 121 and 122 can cooperate with ducts 6 of figures 1A-1D: for example, a fluid flows from the first portion 2 into the second portion 8 through duct 121, then flows through channel 12a and flows out of second portion 8 through duct 122 and then flows back to the 1^st portion.

[0059] Figures 11A-11B show only one inside channel but several channels 12₁, 12₂ can be made inside the second portion, each comprising one or more duct(s) to connect with surface 10 and/or with surface 10'.

[0060] Figure 12 shows 2 inside channels 120₂, 120₂ distributed like those of figure 5A but made inside the second portion by assembling two parts 8₁, 8₂ as explained above. Each channel has its own ducts 121₁, 122₁ and 121₂, 122₂ to communicate with the surface 10 and/or with surface 10'.

[0061] Assembling the two parts 8₁, 8₂ can be made by gluing or soldering said two parts after aligning them so that both half channels 12₁, 12₂ can form a single channel 12a. There is an assembly plane between said two part.

[0062] Inside channels like those illustrated on figures 11A - 12 offer the advantage of avoiding any edge 12s, 12's' (see figure 1C) on the surface which is in contact with surface 4 of the 1^st portion 2 of the device; indeed, dirt and/or ink can be deposited at these edges and dry, which can pose problems of tightness of both contacting surfaces 4, 10. An inside channel can be easily cleaned by a flow of solvent.

[0063] In the above examples, any of the ducts 6, 6₁-6₅, 106, 106₁-106₄ and/or of the channel(s) 12, 12₁-12₂, 112₁-112₃ can have a diameter of up to 2 mm or more, allowing important flow rates, up to 10 l/h or 15 l/h or even more, for example 20 l/h or 100 l/h. Some solenoid valves are compatible with such flow rates, but they are bulky, heavy and expensive.

[0064] In the above examples of figures 11A - 12, the second portion 8 of the device comprises at least one inside channel in which a fluid can flow parallel to surface 10 or 10'.

[0065] In another embodiment, illustrated for example on figures 13A-13B, the second portion 8 has one or more ducts or through ducts 60₁, 60₂ but has no channel for a flow parallel to surface 10 or 10'. Depending on the rotation of portion 8 with respect to portion 2, one or more ducts or through ducts 60₁, 60₂ can be aligned or not with one or more duct(s) 6₁ - 6₃ of the first portion 2; thus, a flow a fluid to flow from one side of the device to the other or from one or more duct(s) 6₁ - 6₃ of the first portion 2 directly to one or more ducts 60₁, 60₂ of the other portion 8.

[0066] This embodiment can also include, in addition, one or more channel(s) 12, 12₁, 12₂ like illustrated on figures 1A-9B or 112₁-112₃ (linear embodiment), and/or one or more inside channel(s) 12a, 12a1, 12a2 like illustrated on figures 11A-12. Thus, a fluid can also flow partly parallel to surface 10 or 10'.

[0067] Assembling steps of a device according to the invention are illustrated on figures 14A-14B.

[0068] A driving section 40 has 2 parallel surfaces 40' and 40". It comprises studs 41 distributed on one of said surface 40' to penetrate into holes 21 of second section 8.

[0069] The other main surface 40" of said driving section 40 comprises a drive shaft 43s.

[0070] A pressure spring 31 presses on the driving section of the hydraulic distributor when the device is assembled and accommodated in a hole 51 of a body 50 (figure 14C), said spring being compressed between said driving section 43 and an end plate 52 of the body 50 which closes the hole 51. The driving shaft 43s traverses the plate 52 through a central hole 52_h. A motor (not illustrated on the figure), for example an electric or hydraulic or pneumatic motor, can drive the shaft 43s, and the second portion 8, in rotation, to change the position of the channel 12 with respect to the first portion, thus varying the fluid communication of the distributor, for example as illustrated on figures 3A and 3B.

[0071] A device according to the invention is adapted to a printer comprising a single-nozzle or a multi-nozzle ink jet print head, as represented on figures 1 and 17 of EP 17186002.

[0072] A device according to the invention is implemented in any part of a fluid circuit of a CIJ printer, to replace any known valve, in particular any solenoid valve.

[0073] In particular a device according to the invention can be positioned upstream of any pump which pumps ink or solvent from an ink tank or from an ink cartridge or from a solvent tank or cartridge and which is to be sent to a main tank or to a print head of a CIJ printer.

[0074] Alternatively, it can be positioned downstream of any pump which pumps ink or solvent, with a pressure of fluid circulating in said pump of up to several bars, for example 3 or 5 bars.

[0075] A device according to the invention can be operated so as to guide a flow of fluid, for example ink and/or solvent of an ink jet printer:

• from at least one duct or inlet duct,
• then possibly through a channel like channel 12, 112, thus flowing partly parallel to surface 10 or 10';
• and then through at least another duct or outlet duct.

[0076] The fluid flow rate can be comprised between 1l/h or 5 l/h and 10 l/h or 15 l/h or even more, for example 20 l/h or 100 l/h.

[0077] The pressure of fluid circulating in a device according to the invention can be higher than 1 or 2 bars, and up to several bars, for example less than 3 or 5 bars or even 10 bars.

[0078] Said fluid can be pumped by a pump of an ink circuit of a CIJ printer.

Claims

1. Hydraulic distributor for an ink-jet printer, comprising:

- a first portion (2, 102), comprising at least one 1^st planar surface (4, 104), a second portion (8, 108), comprising at least one 2^nd planar surface (10, 110), both planar surfaces being in friction contact with each other;

- at least one 1^st conduct (6, 6₁ - 6₆, 106₁ - 106₄) in said 1^st portion, each comprising a 1^st opening in said 1^st planar surface;

- at least one channel (12, 12₁ - 12₂; 112₁ - 112₄) extending in said second portion (8, 108), to conduct a fluid in a direction substantially parallel to said 2^nd planar surface;

- at least one 2^nd conduct in one of said portions, comprising a 2^nd opening in said 1^st planar surface or in said 2^nd planar surface or in said at least one channel;

- means (22, 27) for moving both portions with respect to each other, so that:

* in a first position, at least both the 1^st opening and the 2^nd opening open in said at least one channel and are connected through said at least one channel;

* and, in a second position, one of said 1^st opening and 2^nd opening does not open in said at least one channel, and are not connected through said at least one channel.

2. Hydraulic distributor according to claim 1, said at least one channel (12, 12₁ -12₂; 112₁ -112₄) extending in said 2^nd planar surface.

3. Hydraulic distributor according to claim 1 or 2, said means (22, 27) for moving both portions with respect to each other being able to move at least one of said portions circularly around an axis perpendicular to both said 1^st planar surface and said 2^nd planar surface.

4. Hydraulic distributor according to claim 3, said means for moving both portions with respect to each other comprising a rotating shaft (22), which extends along said axis.

5. Hydraulic distributor according to claim 4, one end of said shaft being inserted in a hole in said 2^nd portion.

6. Hydraulic distributor according to claim 5, each of said shaft and said hole comprising a flat surface (22, 24) which extends parallel to said axis and which cooperate which each other to rotate both said shaft and said 2^nd portion.

7. Hydraulic distributor according to claim 1 or 2, said means for moving both portions with respect to each other being able to move at least one of said portions in translation along an axis parallel to both said 1^st planar surface and said 2^nd planar surface.

8. Hydraulic distributor according to any of claims 1 to 7, further comprising means (30), for example a spring, for pressing said 1^st planar surface and said 2^nd planar surface against each other.

9. Hydraulic distributor according to any of claims 1 to 8, said 1^st portion comprising at least 2 or 3 conducts, each comprising an opening in said 1^st planar surface.

10. Hydraulic distributor according to any of claims 1 to 9, said 1^st planar surface and said 2^nd planar surface:

- being made of glass material or of a ceramic material or of stainless steel;

- and/or having a roughness of between 0,4 µm and 0,8 µm.

11. Hydraulic distributor according to any of claims 1 to 10, said 1^st portion comprising at least 3 conducts, each comprising an opening in said 1^st planar surface, so that said channel connects, in said first position, a first pair of said at least 3 conducts and, in said second position, another pair of said at least 3 conducts.

12. Hydraulic distributor according to any of claims 1 to 11, comprising a plurality of channels extending in said 2^nd planar surface, to conduct a fluid in at least two different directions substantially parallel to said 2^nd planar surface.

13. Hydraulic distributor according to any of claims 1 to 12, said means for moving both portions with respect to each other comprising a motor.

14. An ink jet printer comprising a print head and an ink supply circuit, said ink supply circuit comprising at least one hydraulic distributor according to any of claims 1 to 13.

15. A method for operating an inkjet printer according to claim 14, comprises moving both portions of said at least one hydraulic distributor with respect to each other between said first positions and said second position, so that:

* in said first position, both the 1^st opening and the 2^nd opening open in said at least one channel and a fluid, for example ink and/or solvent, flows from one of said opening to the channel and then to the other of said openings;

* and, in said second position, one of said 1^st opening and 2^nd opening does not open in said at least one channel, and no fluid flows from one of said openings to the other one.

Drawing