Ink regulator for ink-jet printer

Abstract

The invention relates to an ink regulator (14) for an inkjet printer, comprising a body (18) with an ink damping chamber (24), said ink regulator (14) further comprising a heat transfer element (26), at least one ink inlet (28) and at least one ink outlet (34), the body (18), the heat transfer element (26), the at least one ink inlet (28) and the at least one ink outlet (34) are made of the same material and are formed in a single piece.

Description

Technical Field

[0001] The invention relates to an ink regulator for an inkjet printer. Background Art

[0002] Inkjet printers are commonly used to digitally print a variety of products such as labels, textiles, tiles, etc. by dispensing small droplets of ink through the nozzles of the print head.

[0003] In order to obtain consistent and high-quality prints, ink parameters such as ink viscosity, ink flow and ink pressure must be precisely controlled. If the ink viscosity is too high and / or the ink meniscus pressure is too low, the ink may not leave the printhead nozzle. Conversely, ink viscosity that is too low or the meniscus pressure that is too high may result in the formation of satellite droplets and reduce the overall print quality. In addition, when inkjet printing on porous substrates, the resulting print dots are affected by the viscosity-related diffusion of the ink on the substrate and the penetration of the ink into the substrate.

[0004] Especially in high-throughput industrial inkjet printing, ink control is often complex and requires a sophisticated ink management system with manifolds that distribute ink to individual printheads and / or control ink temperature to achieve the desired viscosity.

[0005] Furthermore, in advanced inkjet printers, ink regulators are used to precisely control ink parameters directly at the printhead inlet and / or outlet. Such ink regulators may include means for measuring and regulating ink pressure, means for measuring and regulating ink temperature, means for flushing the printhead, means for circulating ink through the printhead, and means for damping vibrations in the ink and / or even out variations in ink flow rate and / or ink pressure that may be caused by an ink circulation pump.

[0006] Ink regulators known in the prior art usually include a number of different parts, such as hoses, connectors and seals, which are made of different materials and assembled together. As a result, the regulator is prone to errors and / or disturbances, such as seal leakage or clogging due to the formation of ink deposits, which can occur if the ink is incompatible with one of the materials constituting the regulator. Summary of the invention

[0007] The object of the present invention is to provide an ink regulator for an inkjet printer which is less susceptible to such errors and / or disturbances and thus improves the stability of the printing process.

[0008] The object of the present invention is solved by an ink regulator for an inkjet printer, which ink regulator includes a main body with an ink damping chamber, and the ink regulator also includes a heat transfer element, at least one ink inlet and at least one ink outlet, wherein the main body, the heat transfer element, at least one ink inlet and at least one ink outlet are composed of the same material and form a single piece.

[0009] In this context, the term "inlet" refers to the opening through which liquid can enter the regulator. The term "outlet" refers to the opening through which liquid can leave the regulator.

[0010] It is envisioned that the ink damping chamber functions to damp oscillations within the ink and / or to even out ink flow rate and / or ink pressure fluctuations. The heat transfer element may be used to adjust the ink temperature.

[0011] The proposed regulator structure with different regulator elements, which form a single piece from the same material, reduces the workload of assembling the regulator. In addition, the total number of individual components and materials used and thus potential failure points are reduced compared to conventional regulators.

[0012] In one embodiment, the body, the heat transfer element, the at least one ink inlet and the at least one ink outlet are manufactured by rapid prototyping, in particular 3D printing, and consist of metal.

[0013] Rapid prototyping and / or 3D printing technologies enable the manufacture of the main components of the regulator in a single and cost-effective processing step, even if the regulator has a complex geometry.

[0014] Preferably, the body, the heat transfer element, the at least one ink inlet and the at least one ink outlet are composed of titanium. This metal provides high hardness and excellent corrosion resistance. In addition, titanium is diamagnetic and therefore less likely to interfere with electronic components.

[0015] In a further embodiment, the ink regulator comprises a membrane and a spring plate for sealing the ink damping chamber, wherein the membrane is located between the body and the spring plate. The membrane is elastically deformable. If the ink pressure in the ink damping chamber fluctuates, the membrane can be deflected inwardly and / or outwardly so that the pressure fluctuation is damped. The spring plate stabilizes the membrane and limits the maximum deflection.

[0016] It is conceivable that the ink damping chamber is circular. This enables a circular membrane to be used to seal the ink damping chamber. Due to the circular shape, the membrane deforms symmetrically. This enables damping in a relatively high pressure range and improves process control overall.

[0017] In order to achieve a very space-saving design, the body may include at least one linear channel having an opening in the ink damping chamber, in which opening the spring plate guide may be placed. In particular, the spring plate guide may be a spring-loaded piston pressed against the spring plate to ensure accurate and smooth movement of the spring plate.

[0018] In another variation, the heat transfer element includes a cavity configured to receive the heating element and an ink channel surrounding the cavity. This allows the ink to be heated without direct contact between the ink and the heating element.

[0019] Preferably, the ink channel comprises an ink outlet configured to be directly connected to an inlet of the print head. The arrangement close to the print head improves the accuracy of the printing temperature control. By a short flow path between the sensor and the print head, a deviation between the set temperature and the actual printing temperature is prevented or at least minimized.

[0020] In a further embodiment, the regulator comprises a first pressure sensor configured to measure the ink pressure in the ink channel within a first pressure range, and a second pressure sensor configured to measure the ink pressure in the ink channel within a second pressure range. In particular, the first pressure sensor may be configured to accurately measure low ink pressures of no more than 50 mbar. The second pressure sensor may be configured to measure high pressures of no more than 1 bar. This improves the overall accuracy of ink pressure measurement and / or control over the overall application-relevant pressure range.

[0021] In addition, the ink regulator may include a connection area configured to receive a screw or bolt for directly connecting the ink regulator to the printhead. This facilitates assembly. In addition, a rigid connection may be formed between the regulator and the printhead, which reduces the risk of leakage at the interface between the two components.

[0022] In a further variant, the regulator comprises a valve for flushing the print head. This enables quick and convenient cleaning of the print head, for example to restore clogged nozzles without disassembling the printer and / or the printing unit. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Further advantages and features will become apparent from the following description of the invention and from the accompanying drawings, which show non-limiting example embodiments of the invention and in which:

[0024] - Figure 1 schematically shows a side view of a printing unit for an inkjet printer;

[0025] - Figure 2 A 3D schematic diagram of an ink regulator according to the present invention is shown;

[0026] - Figure 3 Shows Figure 2 The regulator includes the 3D printed parts.

[0027] - Figure 4 Shows Figure 2 An exploded view of the ink regulator;

[0028] - Figure 5 Shows Figure 2 A first cross section of the regulator; and

[0029] - Figure 6 Shows Figure 2 The second cross section of the regulator. DETAILED DESCRIPTION

[0030] Figure 1 A side view of a printing unit 10 for an industrial single-pass inkjet printer is schematically shown. It is conceivable that the inkjet printer is equipped with a plurality of such printing units 10, which form a stack defining the printing width of the printer.

[0031] The printing unit 10 comprises a manifold 12, four ink regulators 14 and four piezoelectric inkjet print heads 16, for example Dimatix Samba print heads with a plurality of individually addressable nozzles arranged on a trapezoidal nozzle disk.

[0032] In the depicted embodiment, the manifold 12 includes means for controlling the temperature of the ink, such as a body 18 with an ink chamber 20 in thermal contact with a temperature-controlled fluid chamber 22, and means for distributing the ink to the individual regulators 14, particularly multiple inlets and outlets for the ink.

[0033] Figure 2 A 3D schematic diagram of an ink regulator 14 according to the present invention is shown, which is adapted to receive ink from a manifold 12. The regulator 14 comprises a body 18 with a circular ink damping chamber 24, in particular for damping pressure fluctuations in the ink induced by a circulation pump.

[0034] The regulator 14 also includes a heat transfer element 26 for fine-tuning the ink temperature, through which ink can enter the two ink inlets 28 of the regulator 14, especially the main ink inlet 30 and the return ink inlet 32, and through which ink can leave the regulator 14 through two ink outlets 34, especially the main ink outlet 36 and the print head outlet 38.

[0035] The depicted regulator 14 also includes a connection area 40 that is configured to receive a screw or bolt for directly connecting the ink regulator 14 to the printhead 16 .

[0036] In the depicted embodiment, the body 18, heat transfer element 26, ink inlet 28, ink outlet 34, and connection area 40 are formed as a single piece and are comprised of 3D printed titanium.

[0037] The 3D schematic diagram of the single piece is Figure 3 Shown in.

[0038] The single piece may include other components, such as a liquid inlet, such as flushing inlet 42, through which flushing liquid for printhead cleaning may enter the regulator 14.

[0039] In the embodiment, the single piece further comprises three linear channels 44 with openings 46 in the ink damping chamber 24 for receiving movable parts, in particular guides.

[0040] It is conceivable that Figure 3 The entire structure shown including the body 18, heat transfer element 26, ink inlet 28, ink outlet 34, connection area 40, flushing inlet 42 and three linear vias 44 is 3D printed in a single and cost-effective processing step.

[0041] Despite the large number of different components and the complex structure, the single piece does not include any seals or similar parts made of rubber or similar materials. It is therefore very durable and, due to the inertness of the titanium surface, it is highly compatible with many different types of inks, especially those containing polar and / or non-polar and / or organic solvents.

[0042] In the depicted embodiment, the regulator 14 includes a number of other components mounted to a 3D printed titanium structure.

[0043] Figure 4 An exploded view of these ink regulator components is shown, which include a circulation pump 48, a valve 50 for regulating the flow of liquid through the print head outlet 38, a valve 52 for allowing print head flushing, and in particular a sealed circuit board 54 for controlling the circulation pump 48 and / or valves 50, 52.

[0044] In the depicted example, the circulation pump 48 is located between the ink return inlet 32 ​​and the main ink outlet 36. Thus, the circulating ink flows through the print head 16 before passing through the circulation pump 48.

[0045] It is contemplated that the manifold 12 forms part of an ink circulation system. As an example, a circulation pump 48 may generate ink flow from the manifold 12 to the regulator 14, from the regulator 14 to the printhead 16, from the printhead 16 to the regulator 14, and from the regulator 14 back to the manifold 12.

[0046] Valve 50 may regulate and / or interrupt ink circulation, for example if the printhead is to be cleaned and / or flushed.

[0047] The ink regulator 14 further includes a circular diaphragm 56 for sealing the ink damping chamber 24 , a spring plate 58 , and a spring plate guide 60 .

[0048] Figure 5 A first cross section of the assembled regulator 14, and in particular the ink damping chamber 24 and corresponding components, is shown.

[0049] The membrane 56 is elastically deformable and is located between the body 18 and the spring plate 58. If the ink pressure in the ink damping chamber 24 fluctuates, the membrane 56 can be symmetrically deformed and / or deflected toward and / or away from the body 18, thereby changing the chamber volume so that the pressure fluctuation is damped. The spring plate 58 stabilizes the membrane 56 during the deflection process and limits its maximum travel.

[0050] The spring plate guide 60 is a spring-loaded piston that is movably mounted in the linear passage 44 of the body 18. Due to the spring mounting, the spring plate guide 60 presses against the membrane 56 and / or the spring plate 58, thereby ensuring accurate and smooth spring plate movement. It is contemplated that the damping characteristics of the ink damping chamber 24 depend on the Young's modulus of the mounting spring and / or the spring plate 58.

[0051] Figure 6 A second cross section of the assembled regulator 14 , in particular the heat transfer element 26 , is shown.

[0052] In an embodiment, the heat transfer element 26 includes a cavity within which the heating element 64, particularly a resistive heater, is located.

[0053] The heat transfer element 26 also includes ink channels surrounding the heater cavity.

[0054] It is contemplated that the walls forming the heater cavity and the surrounding ink channel are composed of 3D printed titanium having a high thermal conductivity. Thus, the heat generated by the heating element 64 is efficiently directed to the ink within the ink channel.

[0055] The ink channel includes an ink outlet, in the embodiment a printhead outlet 38, which is directly connected to the inlet of the printhead 16. Thus, the ink temperature of the ink can be adjusted directly before the ink enters the printhead 16.

[0056] In the depicted example, the regulator 14 also includes a first pressure sensor 68 configured to measure ink pressure within the ink channel within a first pressure range, and a second pressure sensor 70 configured to measure ink pressure within the ink channel within a second pressure range.

[0057] The use of multiple pressure sensors 68, 70 of varying ranges improves the overall accuracy of ink pressure measurement and thereby process control.

Claims

1. An ink regulator for an inkjet printer, comprising a body (18) with an ink damping chamber (24), the ink regulator (14) further comprising a heat transfer element (26), at least one ink inlet (28) and at least one ink outlet (34), wherein: The body (18), the heat transfer element (26), the at least one ink inlet (28) and the at least one ink outlet (34) are composed of the same material and formed as a single piece.

2. The ink regulator according to claim 1, wherein: The body (18), the heat transfer element (26), the at least one ink inlet (28), and the at least one ink outlet (34) are comprised of 3D printed metal.

3. The ink regulator according to claim 1 or 2, wherein: The body (18), the heat transfer element (26), the at least one ink inlet (28), and the at least one ink outlet (34) are composed of titanium.

4. An ink regulator according to any one of the preceding claims, wherein: The ink damping chamber (24) is circular.

5. The ink regulator according to any one of the preceding claims, further comprising a membrane (56) and a spring plate (58) for sealing the ink damping chamber (24), wherein: The membrane (56) is located between the body (18) and the spring plate (58).

6. An ink regulator according to any one of the preceding claims, wherein: The body (18) includes at least one linear passage (44) having an opening (46) within the ink damping chamber (24), the opening (46) being configured to receive a spring plate guide (60).

7. An ink regulator according to any one of the preceding claims, wherein: The heat transfer element (26) includes a cavity configured to receive a heating element (64) and an ink channel surrounding the cavity.

8. The ink regulator according to claim 7, wherein: The ink channel includes an ink outlet (34) configured to be directly connected to an inlet of a print head (16).

9. The ink regulator according to claim 7 or 8 further includes a first pressure sensor (68) configured to measure the ink pressure within the ink channel within a first pressure range, and a second pressure sensor (70) configured to measure the ink pressure within the ink channel within a second pressure range.

10. The ink regulator of any of the preceding claims, further comprising a connection area (40) configured to receive a screw or bolt for directly connecting the ink regulator (14) to a printhead (16).

11. An ink regulator according to any one of the preceding claims, further comprising a valve (52) for print head flushing.

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