Manifold for an inkjet printer

Abstract

The present invention relates to a manifold for an inkjet printer comprising a body (18) having an ink cavity and a temperature control fluid cavity in thermal contact with the ink cavity, the manifold (12) further comprising at least one ink inlet (28), at least one ink outlet (34), at least one temperature control fluid inlet (40), and at least one temperature control fluid outlet (50), the body (18), at least one ink inlet (28), at least one ink outlet (34), at least one temperature control fluid inlet (40), and at least one temperature control fluid outlet (50) being formed of the same material to form a one-piece article.

Description

Technical Field

[0001] The present invention relates to a manifold for an inkjet printer.

Background Art

[0002] An inkjet printer is typically used to digitally print various products such as labels, fabrics, ceramic tiles, etc. by ejecting small ink droplets from the nozzles of a print head.

[0003] In order to achieve stable high-quality printing, it is necessary to accurately control ink parameters such as ink viscosity, ink flow rate, and ink pressure. If the ink viscosity is too high and / or the meniscus pressure of the ink is too low, the ink may not be able to come out of the nozzles of the print head. In contrast, if the ink viscosity is too low or the meniscus pressure is too high, satellite droplets may be formed as a result, and the overall print quality may decrease. Furthermore, when performing inkjet printing on a porous substrate, the resulting printed dots are affected by the spread of the ink on the substrate and the penetration of the ink into the substrate, which depend on the viscosity.

[0004] In particular, in high-throughput industrial inkjet printing, ink control is often complex, and an advanced ink management system is required that has a manifold for distributing ink to a single print head and controlling the ink temperature to achieve the desired viscosity.

[0005] An inkjet manifold known in the art typically includes a plurality of different components such as hoses, connectors, and seals made of different materials and assembled together. As a result, the manifold tends to cause errors and / or malfunctions such as clogging caused by seal leakage or the formation of ink deposits that may occur when the ink is not compatible with one of the materials constituting the manifold.

Summary of the Invention

Problems to be Solved by the Invention

[0006] An object of the present invention is to provide an inkjet manifold that has a low tendency to cause such errors and / or failures, and thus improves the stability of the printing process.

Means for Solving the Problems

[0007] The object of the present invention is solved by a manifold for an inkjet printer comprising a body having an ink cavity and a temperature control fluid cavity in thermal contact with the ink cavity. The manifold further comprises at least one ink inlet, at least one ink outlet, at least one temperature control fluid inlet, and at least one temperature control fluid outlet, and the body, at least one ink inlet, at least one ink outlet, at least one temperature control fluid inlet, and at least one temperature control fluid outlet are made of the same material and form a single molded article.

[0008] As used herein, the term "inlet" refers to an opening through which a liquid can enter the manifold. The term "outlet" refers to an opening through which a liquid can exit the manifold.

[0009] A manifold structure having various manifold elements formed from the same proposed material to form a single molded body reduces the labor of assembling the manifold. Further, compared to conventional manifolds, the total number of individual parts and materials applied is reduced, and thus potential failure points are reduced.

[0010] In one embodiment, the body, at least one ink inlet, at least one ink outlet, at least one temperature control fluid inlet, and at least one temperature control fluid outlet are manufactured by rapid prototyping, specifically 3D printing, and are made of metal.

[0011] Rapid prototyping and / or 3D printing technology enables the manufacture of the main elements of the manifold in a single cost-saving processing step, even if the shape of the manifold is complex.

[0012] Preferably, the body, at least one ink inlet, at least one ink outlet, at least one temperature-controlled fluid inlet, and at least one temperature-controlled fluid outlet are made of titanium. This metal is highly hard and has excellent corrosion resistance. Furthermore, titanium is diamagnetic and thus has no tendency to interfere with electronic circuits.

[0013] The body is contemplated to include a thermally conductive wall that separates the ink cavity and the temperature-controlled fluid cavity. Specifically, the wall can be made of 3D printed titanium. This wall can prevent direct contact between the printed ink and the temperature-controlled fluid while effectively transferring heat between the two liquids.

[0014] In one variation, the body includes a plurality of thermally conductive laminates within the ink cavity. Also, the laminates can be composed of 3D printed titanium. The laminates provide an additional contact surface between the ink and the body through which heat can be transferred. Furthermore, the laminates can affect the ink flow within the ink cavity and are designed to achieve a uniform velocity and / or ink pressure distribution.

[0015] To further improve the heat transfer between the ink and the temperature-controlled fluid, the laminates can be arranged to extend perpendicularly from the thermally conductive wall through the ink cavity. The laminates are contemplated to extend perpendicularly from the thermally conductive wall across the entire cross-section of the ink cavity.

[0016] To enable the ink to spread between the laminar plates and / or flow through the entire cavity, each of the laminar plates can be provided with at least one opening for the ink to pass through. Of course, the laminar plate can be provided with two or more openings. The ink openings can be, for example, circular and can be distributed equidistantly across the entire laminar plate to achieve a laminar flow and / or a homogeneous ink flow through the ink cavity.

[0017] In one embodiment, the body comprises a plurality of thermally conductive laminar plates within the control fluid cavity. The laminar plates increase the contact surface between the body and the temperature control fluid, thus increasing the heating and / or cooling efficiency.

[0018] Preferably, both the ink cavity and the control fluid cavity are provided with laminar plates. As an example, the laminar plates within the ink cavity and the laminar plates within the control fluid cavity can be oriented parallel or perpendicular to each other to achieve efficient heat transfer between the ink and the temperature control fluid across the entire cavity dimensions.

[0019] In a further embodiment, the manifold comprises at least four ink outlets each configured to supply ink to a corresponding print head and / or ink conditioner, and at least four ink inlets each configured to return ink from a corresponding print head and / or ink conditioner, and the ink can circulate between the manifold and the print head and / or ink conditioner during the printing process. By using a manifold to supply ink to multiple print heads, the total number of individual printer components can be reduced, resulting in cost savings in manufacturing and a reduction in potential error sources. Further, the circulation of the ink through the manifold reduces or prevents ink degradation such as deposition and / or debris formation within the ink flow path, resulting in an improvement in the overall stability of the printing process.

[0020] In another variant of the manifold, at least one temperature-controlled fluid outlet is configured to supply temperature-controlled fluid to the printhead control circuit board cooler, and at least one temperature-controlled fluid inlet is configured to return temperature-controlled fluid from the printhead control circuit board cooler to the manifold. This allows the use of temperature-controlled fluid from the manifold to cool the printhead control circuit board, specifically the firing pulse generator for the piezoelectric printhead. Thus, a separate unit for cooling the electronic circuit is not required.

[0021] In a further embodiment, the body of the manifold has a substantially flat outer surface that is thermally coupled to the temperature-controlled fluid cavity. The flat surface allows the drive control electronic circuit and / or the control electronic circuit to be mounted directly on the manifold. Preferably, the body surface is made of metal, specifically 3D printed titanium. This material has a high thermal conductivity of over 20 W / m * K and can effectively dissipate heat from the contacting circuit board.

[0022] Further advantages and features should become apparent from the following description of the invention and the accompanying drawings showing non-limiting exemplary embodiments of the invention.

Brief Description of the Drawings

[0023]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Mode for Carrying Out the Invention

[0024] Figure 1 schematically shows a side view of a printing unit 10 of an industrial single-pass inkjet printer. The inkjet printer is provided with a plurality of such printing units 10, and the printing units are intended to form a stack that defines the printing width of the printer.

[0025] The printing unit 10 includes a manifold 12, four ink conditioners 14, and four piezo inkjet printheads 16, for example, a Dimatix Samba printhead having a plurality of individually addressable nozzles disposed on a trapezoidal nozzle plate.

[0026] The manifold 12 includes a body 18 having an ink cavity 20, a temperature control fluid cavity 22 that is in thermal contact with the ink cavity 20, and an ink collection cavity 24.

[0027] A heat conductive wall 26, which is part of the body 18, separates the ink cavity 20 and the temperature control fluid cavity 22 from each other so that the ink cannot come into direct contact with the temperature control fluid.

[0028] In this particular embodiment, the control fluid cavity 22 surrounds the ink cavity 20 at the bottom as well as at the top. This enables rapid and accurate temperature adjustment of the ink inside the ink cavity 20 by heat conduction through the wall 26.

[0029] The manifold 12 further includes a plurality of ink inlets 28 through which ink can enter the manifold 12, specifically a main ink inlet 30 and four ink return inlets 32.

[0030] The main ink inlet 30 is adapted to connect an ink source, for example, an ink reservoir, to the ink cavity 20 within the body 18.

[0031] The four ink return inlets 32 are adapted to connect the ink outlets of the printhead 16 and / or the conditioner 14 to the ink return cavity 24.

[0032] The manifold 12 further includes a plurality of ink outlets 34 from which ink can exit the manifold 12, specifically, a main ink outlet 36 and four print head supply outlets 38.

[0033] The main ink outlet 36 is configured to discharge ink from the ink return cavity 24, for example, discharging the ink to an ink purification unit and / or an ink reservoir and / or an ink cavity 20.

[0034] Each of the four print head supply outlets 38 is connected to a corresponding conditioner inlet or print head inlet, and thus is adapted to supply ink from the ink cavity 20 to the conditioner 14 and / or the print head 16 for printing.

[0035] In the described embodiment, ink can flow, for example, from an ink reservoir into the ink cavity 20 within the manifold 12, where the ink is heated or cooled to a certain temperature. The ink can further flow from the ink cavity 20 into the conditioner 14 and / or the print head 16, where a portion of the ink is ejected from the nozzles. The remaining ink further flows from the conditioner 14 and / or the print head 16 into the ink return cavity 24 of the manifold 12, and can flow from the ink return cavity 24 into the purification unit and / or the ink reservoir, and finally back to the ink cavity 20. In other words, the manifold 12 can be part of an ink circulation system. The ink can circulate, for example, between the manifold 12 and the print head 16 and / or the ink conditioner 14 during the printing process.

[0036] The manifold 12 further includes a plurality of temperature control fluid inlets 40 through which temperature control fluid can enter the manifold 12, specifically, a main temperature control fluid inlet 42 and two or more temperature control fluid return inlets 44.

[0037] The main temperature control fluid inlet 42 is adapted to be connected to a cooling device, and a temperature control fluid at a specific temperature can be supplied from the cooling device to the temperature control fluid cavity 22 through the main temperature control fluid inlet 42.

[0038] Two or more temperature control fluid return inlets 44 are adapted to connect additional components of the inkjet printer (for example, a cooler for an electronic circuit, specifically, a cooler for the conditioner 14 and / or the printhead 16 and / or a printhead control circuit board cooler 46 (such as a firing pulse generator cooler)) to a manifold, specifically, the temperature control fluid cavity 22 or an additional control fluid return cavity 48, and the temperature control fluid can flow from the additional components to the manifold 12.

[0039] The manifold 12 further includes a plurality of temperature control fluid outlets 50 through which the temperature control fluid can exit the manifold 12, specifically, a main temperature control fluid outlet 52 and two or more peripheral temperature control fluid outlets 54.

[0040] The main temperature control fluid outlet 52 is adapted to be connected to a cooling device, and the temperature control fluid is adapted to be supplied from the manifold 12, specifically, from the control fluid cavity 22 or from the additional control fluid return cavity 48 to the cooling device.

[0041] Two or more peripheral temperature control fluid outlets 54 are adapted to connect the temperature control fluid cavity 22 to the above-mentioned additional components of the inkjet printer that require cooling, and the temperature control fluid can flow from the temperature control fluid cavity 22 to these components.

[0042] In the described embodiments, the temperature control fluid flows, for example, from a cooling device into the temperature control fluid cavity 22 within the manifold 12, from the temperature control fluid cavity 22 to additional components (such as coolers for the conditioner 14 and / or the printhead 16 and / or the firing pulse generator cooler 46), into the temperature control fluid return cavity 48 from the additional components, and can return from the temperature control fluid return cavity 48 to the cooling device.

[0043] The described temperature control fluid circulation is contemplated to comprise parallel flow paths, for example, one path comprising the firing pulse generator cooler 46 and another path comprising a cooler for the conditioner 14 and / or the printhead 16. This leads to a reduction in the flow resistance of the liquid and thus a reduction in the required pump power as compared to a series connection.

[0044] FIG. 2 shows a schematic 3D view of the manifold 12. In the described embodiments, the body 18, the ink inlet 28, the ink outlet 34, the temperature control fluid inlet 40, and the temperature control fluid outlet 50 form a one-piece article and are composed of 3D printed titanium. The entire manifold 12 is contemplated to form a single 3D printed structure as shown in FIG. 2.

[0045] Despite the numerous liquid inlets, outlets, and cavities, the manifold 12 does not comprise seal components or similar components made of rubber or similar materials. Thus, the manifold 12 is very robust and highly compatible with many different types of inks, specifically inks containing polar solvents and / or non-polar solvents and / or organic solvents, due to the inert properties of the titanium surface.

[0046] In the described embodiment, the upper outer surface 56 of the manifold 12 is flat. Since the entire manifold 12 is made of titanium, the surface 56 is thermally coupled to the temperature control fluid cavity 22 located directly below. Therefore, it is possible to directly mount drive and / or control electronic circuits, such as a pulse generation circuit board for launching, on the manifold 12 and dissipate the processing heat and / or waste heat through the outer shell of the manifold 12. This enables an efficient cooling process and a compact design of the printing unit 10.

[0047] Figure 3 shows a side view of the manifold 12 with two cross-section lines A-A and B-B shown.

[0048] Figures 4 and 5 show the first cross-section A-A of Figure 3 showing a cut through the ink cavity 20.

[0049] In the described embodiment, the body 18 includes a plurality of thermally conductive lamellae 58 within the ink cavity 20.

[0050] The lamellae 58 extend vertically from the thermally conductive wall 26 through the ink cavity 20, whereby the ink cavity 20 is separated into a plurality of thin elongated chambers. To allow ink flow between these chambers, each lamella 58 includes a plurality of equally spaced circular holes 60 through which ink can pass. In this way, a laminar ink flow with a uniform velocity distribution can be obtained across the entire ink cavity 20.

[0051] Furthermore, the lamellae 58 increase the contact surface between the manifold 12 and the ink flowing through the ink cavity 20. This enables rapid transfer of thermal energy from the titanium structure of the manifold 12 to the ink, resulting in rapid heating and / or cooling of the ink.

[0052] Figure 6 shows the second cross-section B-B of Figure 3 showing a cut through the temperature control fluid cavity 22.

[0053] In an embodiment, the control fluid cavity 22 also includes a lamination plate 62 that forms part of the main body 18. Similar to the ink chamber lamination plate 58, the temperature control chamber lamination plate 62 improves the transfer of thermal energy and equalizes the flow rate across the cavity.

[0054] As shown in FIGS. 5 and 6, the ink chamber lamination plate 58 and the temperature control chamber lamination plate 62 can be oriented in the same direction. Alternatively, the ink chamber lamination plate 58 and the temperature control chamber lamination plate 62 can be oriented perpendicular to each other. The lamination plate 62 in FIG. 6, for example, can be oriented horizontally rather than vertically. Such an orientation can result in an increase in the heat transfer rate of the temperature control fluid within the control fluid cavity 22 and / or a reduction in the flow resistance, and thus a reduction in the required pump power.

Description of the Reference Numerals

[0055] 12 Manifold 18 Main Body 28 Ink Inlet 34 Ink Outlet 40 Temperature Control Fluid Inlet 50 Temperature Control Fluid Outlet

Claims

**Claim 1** A manifold for an inkjet printer comprising a body (18) having an ink cavity (20) and a temperature control fluid cavity (22) in thermal contact with the ink cavity (20), the manifold (12) further comprising at least one ink inlet (28), at least one ink outlet (34), at least one temperature control fluid inlet (40), and at least one temperature control fluid outlet (50), wherein the body (18), the at least one ink inlet (28), the at least one ink outlet (34), the at least one temperature control fluid inlet (40), and the at least one temperature control fluid outlet (50) are made of the same material and form a one-piece molded article, the manifold. **Claim 2** The manifold according to claim 1, wherein the body (18), the at least one ink inlet (28), the at least one ink outlet (34), the at least one temperature control fluid inlet (40), and the at least one temperature control fluid outlet (50) are made of 3D printed metal. **Claim 3** The manifold according to claim 1 or 2, wherein the body (18), the at least one ink inlet (28), the at least one ink outlet (34), the at least one temperature control fluid inlet (40), and the at least one temperature control fluid outlet (50) are made of titanium. **Claim 4** The manifold according to any one of claims 1 to 3, wherein the body (18) comprises a heat conductive wall (26) separating the ink cavity (20) and the temperature control fluid cavity (22). **Claim 5** The manifold according to any one of claims 1 to 4, wherein the body (18) comprises a plurality of heat conductive laminates (58) in the ink cavity (20). **Claim 6** The manifold according to claims 4 and 5, wherein the laminate (58) extends perpendicularly from the heat conductive wall (26) through the ink cavity (20). **Claim 7** The manifold according to claim 5 or 6, wherein each of the laminates (58) comprises at least one opening (60) for ink to pass through. **Claim 8** The manifold according to any one of claims 1 to 7, wherein the body (18) comprises a plurality of heat conductive laminates (62) in the control fluid cavity (22). **Claim 9** Comprising at least four ink outlets (34) configured to supply ink to a corresponding print head (16) and / or ink conditioner (14) respectively, said manifold (12) further comprising at least four ink inlets (28) each configured to return ink from said corresponding print head (16) and / or said ink conditioner (14), and the ink being able to circulate between said manifold (12) and said print head (16) and / or said ink conditioner (14) during the printing process. The manifold according to any one of claims 1 to 8.

10. At least one temperature-controlled fluid outlet (50) is configured to supply temperature-controlled fluid to a print head control circuit board cooler (46), and at least one temperature-controlled fluid inlet (40) is configured to return said temperature-controlled fluid from said print head control circuit board cooler (46) to said temperature-controlled fluid cavity (22) or temperature-controlled fluid return cavity (48) within said manifold (12). The manifold according to any one of claims 1 to 9.

11. The body (18) comprises a thermally conductive substantially flat outer surface (56) thermally coupled to said temperature-controlled fluid cavity (22). The manifold according to any one of claims 1 to 10.

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