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Title:
INDUSTRIAL PRINTHEAD
Document Type and Number:
WIPO Patent Application WO/2018/042165
Kind Code:
A1
Abstract:
An industrial printhead (100) comprising a flow channel enclosed in a chamber, wherein the flow channel (102) has at least one fluid inlet (102a) and at least one fluid outlet (102b), wherein the flow channel is resonated, in use, by a vibration distributor (104) comprising a mass resonator (103), piezoelectric exciter (108) and wave concentrator (110) arranged in an axial configuration.

Inventors:
HUDD, Alan (Mentor House, Ainsworth Street Blackburn, Lancashire BB1 6AY, BB1 6AY, GB)
KOCSIS, Albert (Mentor House, Ainsworth StreetBlackburn, Lancashire BB1 6AY, BB1 6AY, GB)
Application Number:
GB2017/052516
Publication Date:
March 08, 2018
Filing Date:
August 29, 2017
Export Citation:
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Assignee:
JETRONICA LIMITED (Mentor House, Ainsworth Street Blackburn, Lancashire BB1 6AY, BB1 6AY, GB)
International Classes:
B05B17/06; B41J2/04
Domestic Patent References:
WO2002034526A12002-05-02
Foreign References:
GB1592819A1981-07-08
JPS56137973A1981-10-28
JPS6285948A1987-04-20
Attorney, Agent or Firm:
HANSON, Kevin (Stratagem IPM Limited, Meridian CourtComberton Roa, Toft Cambridge CB23 2RY, GB)
Download PDF:
Claims:
CLAIMS

1. An industrial printhead comprising a flow channel enclosed in a chamber, wherein the flow channel has at least one fluid inlet and at least one fluid outlet, wherein the flow channel is resonated, in use, by a vibration distributor comprising a mass resonator, piezoelectric exciter and wave concentrator arranged in an axial configuration.

2. An industrial printhead according to claim 1, wherein the mass resonator has a greater mass density than the wave concentrator.

3. An industrial printhead according to claim 1 or claim 2, wherein the vibration distributor has a generally cylindrical cross-section.

4. An industrial printhead according to any of claims 1 to 3, wherein the mass resonator is formed from a high density material such as steel or brass.

5. An industrial printhead according to claim 4, wherein the wave concentrator is formed from a high density material having a lower density than steel or brass, such high density material including aluminium or titanium.

6. An industrial printhead according to any of claims 1 to 5, wherein the wave concentrator is conical in shape.

7. An industrial printhead according to any preceding claim, wherein the vibration

distributor is joined to the flow channel.

8. An industrial printhead according to any preceding claim, wherein the mass resonator, piezoelectric exciter and wave concentrator are clamped together axially using an axial fastener.

9. An industrial printhead according to any preceding claim, wherein the flow channel is configured to receive fluid having a viscosity between 20-1000cP.

10. An industrial printhead according to any preceding claim, wherein the flow channel is configured to receive fluid having a range of pigment sizes from 1 micron to 500 micron and/or fluids have particles of different anisotropy.

11. An industrial printhead according to any preceding claim, wherein the at least one fluid outlet comprises two or more fluid outlets.

12. An industrial printhead according to claim 11, wherein each of the two or more fluid outlets has a flow direction perpendicular to the flow direction of the fluid channel.

13. An industrial printhead according to claim 11 or claim 12, wherein each of the two or more fluid outlets are spaced apart from adjacent fluid outlets by 2.54mm.

14. An industrial printhead according to any of claims 11 to 13, wherein each of the two or more fluid outlets are supplied with fluid from a common fluid source.

15. An industrial printhead according to claim 11 to 13, wherein each of the two or more fluid outlets are supplied with fluid from individual fluid sources.

16. An industrial printhead according to claim 14 or claim 15, wherein the, or each, fluid source is provided with heating means to heat the fluid contained therein.

17. An industrial printhead comprising a flow channel enclosed in a chamber, wherein the flow channel has at least one fluid inlet and at least one fluid outlet, wherein the flow channel is resonated, in use, by a vibration distributor comprising a mass resonator, piezoelectric exciter and wave concentrator, wherein the wave concentrator has a lower mass density than the mass resonator.

18. A vibration distributor comprising a mass resonator, piezoelectric exciter and wave concentrator arranged in an axial configuration.

19. A vibration distributor comprising a mass resonator, piezoelectric exciter and wave concentrator, wherein the wave concentrator has a lower mass density than the mass resonator.

20. An industrial printhead as described with reference to, and/or as shown in, figures 3 and 4.

21. An industrial printhead as described with reference to, and/or as shown in, figures 3 and 4.

Description:
INDUSTRIAL PRINTHEAD

FIELD

The present invention relates to an industrial printhead.

BACKGROUND

Piezoactuated needles are known to be useful for the deposition of fluids based on the mechanism described in PCT/HU 1999/000015. However, the industrial application of the technology requires that a number of operational characteristics of the system are improved to ensure consistent operation and achieve the printing of fluids with high viscosity and/or high solids loading of small or large pigment particles, required for many applications.

The printhead design described in PCT/HU1999/000015 had several limitations due to its small construction. The limitations include operating power, and due to the small dissipating surface and small piezo element, which may be 'depolarized' or stop mechanically functioning if overloaded.

In this patent we describe a printhead design that overcomes the industrial limitations of the invention previously described including the following main larger transducer parts and increased vibrating mass, higher input power and the dimensions and quantities of each component material have been modified to increase flow rate down the printing nozzle (including mass resonator, piezo exciter and wave concentrator as shown in Figure 2).

We describe the invention of an industrial printhead configuration that overcomes the limitations of the configuration described in PCT/HU1999/000015 to generate a novel and industrially applicable embodiment of piezo actuated flow channel deposition principle, with increased capability fluids with high viscosity and/or high solids loading of small or large pigment particles

SUMMARY

An aspect of the invention provides an industrial printhead comprising a flow channel enclosed in a chamber, wherein the flow channel has at least one fluid inlet and at least one fluid outlet, wherein the flow channel is resonated, in use, by a vibration distributor comprising a mass resonator, piezoelectric exciter and wave concentrator arranged in an axial configuration.

Advantageously, industrial printheads according to the above aspect of the invention can distribute viscous fluids having a viscosity between 100 - lOOOcP and/or a particle size between 20 - 500 micron plus with different anisotropy.

In one embodiment, the mass resonator has a greater mass density than the wave concentrator.

Advantageously, such a construction provides a higher vibrating amplitude through the wave concentrator.

In one embodiment, the wave concentrator is conical in shape.

A conical shaped wave concentrator provides a focused resonance to the flow channel.

In one embodiment, the at least one fluid outlet comprises two or more fluid outlets. In another embodiment each of the two or more fluid outlets has a flow direction perpendicular to the flow direction of the fluid channel. Configuration of piezoactuated flow channel depositors to form an array that can be used industrially as a reliable digital printhead facilitates printing of fluids with high viscosity and/or high solids loading of small or large pigment particles

An aspect of the invention provides an industrial printhead comprising of a single piezoactuated flow channel dispenser enclosed in a chamber. Due to the printhead's larger three dimensional shape, individual nozzle cannot be stacked at a low pitch, and therefore a multi-nozzle construction has also been developed, comprising of a single vibrating system to drive multiple jetting nozzles.

FIGURES

Figure 1 shows a side view of a prior art industrial printhead ;

Figure 2 shows an aerial view of the industrial printhead of figure 1;

Figure 3 shows one embodiment of industrial printhead according to aspects of the invention as compared to the prior art industrial printhead of figure 1;

Figure 4 shows a three-dimensional view of a multiple orifice nozzle plate design.

DESCRIPTION

A prior art industrial printhead design developed by the applicant is demonstrated in Figures 1 and 2. The prior art industrial printhead (10) shown in figures 1 and 2 comprises a flow channel (12) having a fluid inlet (12a) and a fluid outlet (12b). A vibration distributor (14) is positioned in contact with the flow channel (12). The vibration distributor comprises a piezoelectric exciter (16) mounted to a plate resonator (18). Upon activation of the piezoelectric exciter (16), the plate resonator vibrates to enable viscous fluid to pass through the flow channel (12) from the fluid inlet (12a) to the fluid outlet (12b). The prior art industrial printhead (10) shown in figures 1 and 2 is constructed in a two dimensional shape to enableindividual nozzles to be placed at a close pitch of 2.54mm to achieve sufficient printing resolution by individually addressing each needle on or off.

A first embodiment of industrial printhead (100) according to the present invention is shown in figure 3. The industrial printhead (100) comprises a flow channel (102) having a fluid inlet (102a) and a fluid outlet (102b). A vibration distributor (104) is positioned in contact with the flow channel (102). The vibration distributor (104) comprises a mass resonator (106), a piezoelectric exciter (108) and a wave concentrator (110) arranged in axial alignment such that the piezoelectric exciter (108) is positioned between the mass resonator (106) and the wave concentrator (110). The mass resonator (106), piezoelectric exciter (108) and wave concentrator are clamped together in axial alignment using an axial fastener (not shown) such as a screw.

The vibration distributor (104) is generally cylindrical in shape with the wave concentrator (110) forming a cone such that the diameter of the wave concentrator (110), and consequently its mass, decreases along its length away from the piezoelectric exciter (108). The mass resonator (106) is made from a high density material such as steel or brass, for example. The wave concentrator (110) is also made from a high density material but the material of the wave concentrator (110) has a lower mass density than that of the mass resonator (106). The wave concentrator (110) may be made from titanium or aluminium, for example.

Figure 4 shows a second embodiment of the invention. The industrial printhead (200) shown in figure 4 comprises a flow channel (202) having a fluid inlet (202a) and multiple fluid outlets (202b). The vibration distributor (104) shown in figure 3 is positioned in contact with the flow channel (202) such that the vibration distributor (104) can drive fluid through each of the multiple fluid outlets (202b). The embodiment envisaged in figure 4 requires each of the multiple fluid outlets (202b) to be supplied with fluid from a common fluid source. The common fluid source may comprise temperature regulating means (not shown) to regulate the temperature of the fluid contained therein.

Although figure 4 is described with reference to each of the multiple fluid outlets (202b) being supplied with fluid from a common fluid source, it will be appreciated that each of the multiple fluid outlets (202b) may also be supplied with fluid from respective individual fluid sources. In such an embodiment, further fluidic control elements will be required.