CA2155942A1 - Method and apparatus for the production of droplets - Google Patents
Method and apparatus for the production of dropletsInfo
- Publication number
- CA2155942A1 CA2155942A1 CA002155942A CA2155942A CA2155942A1 CA 2155942 A1 CA2155942 A1 CA 2155942A1 CA 002155942 A CA002155942 A CA 002155942A CA 2155942 A CA2155942 A CA 2155942A CA 2155942 A1 CA2155942 A1 CA 2155942A1
- Authority
- CA
- Canada
- Prior art keywords
- viscosity
- ejection
- ink
- ejection point
- point
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Abandoned
Links
Classifications
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B05—SPRAYING OR ATOMISING IN GENERAL; APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
- B05B—SPRAYING APPARATUS; ATOMISING APPARATUS; NOZZLES
- B05B5/00—Electrostatic spraying apparatus; Spraying apparatus with means for charging the spray electrically; Apparatus for spraying liquids or other fluent materials by other electric means
- B05B5/007—Electrostatic spraying apparatus; Spraying apparatus with means for charging the spray electrically; Apparatus for spraying liquids or other fluent materials by other electric means the high voltage supplied to an electrostatic spraying apparatus during spraying operation being periodical or in time, e.g. sinusoidal
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B05—SPRAYING OR ATOMISING IN GENERAL; APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
- B05B—SPRAYING APPARATUS; ATOMISING APPARATUS; NOZZLES
- B05B5/00—Electrostatic spraying apparatus; Spraying apparatus with means for charging the spray electrically; Apparatus for spraying liquids or other fluent materials by other electric means
- B05B5/001—Electrostatic spraying apparatus; Spraying apparatus with means for charging the spray electrically; Apparatus for spraying liquids or other fluent materials by other electric means incorporating means for heating or cooling, e.g. the material to be sprayed
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B05—SPRAYING OR ATOMISING IN GENERAL; APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
- B05B—SPRAYING APPARATUS; ATOMISING APPARATUS; NOZZLES
- B05B5/00—Electrostatic spraying apparatus; Spraying apparatus with means for charging the spray electrically; Apparatus for spraying liquids or other fluent materials by other electric means
- B05B5/025—Discharge apparatus, e.g. electrostatic spray guns
- B05B5/0255—Discharge apparatus, e.g. electrostatic spray guns spraying and depositing by electrostatic forces only
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B05—SPRAYING OR ATOMISING IN GENERAL; APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
- B05B—SPRAYING APPARATUS; ATOMISING APPARATUS; NOZZLES
- B05B5/00—Electrostatic spraying apparatus; Spraying apparatus with means for charging the spray electrically; Apparatus for spraying liquids or other fluent materials by other electric means
- B05B5/025—Discharge apparatus, e.g. electrostatic spray guns
- B05B5/053—Arrangements for supplying power, e.g. charging power
- B05B5/0533—Electrodes specially adapted therefor; Arrangements of electrodes
- B05B5/0536—Dimensional characteristics of electrodes, e.g. diameter or radius of curvature of a needle-like corona electrode
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B41—PRINTING; LINING MACHINES; TYPEWRITERS; STAMPS
- B41J—TYPEWRITERS; SELECTIVE PRINTING MECHANISMS, i.e. MECHANISMS PRINTING OTHERWISE THAN FROM A FORME; CORRECTION OF TYPOGRAPHICAL ERRORS
- B41J2/00—Typewriters or selective printing mechanisms characterised by the printing or marking process for which they are designed
- B41J2/005—Typewriters or selective printing mechanisms characterised by the printing or marking process for which they are designed characterised by bringing liquid or particles selectively into contact with a printing material
- B41J2/01—Ink jet
- B41J2/015—Ink jet characterised by the jet generation process
- B41J2/04—Ink jet characterised by the jet generation process generating single droplets or particles on demand
- B41J2/06—Ink jet characterised by the jet generation process generating single droplets or particles on demand by electric or magnetic field
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B41—PRINTING; LINING MACHINES; TYPEWRITERS; STAMPS
- B41J—TYPEWRITERS; SELECTIVE PRINTING MECHANISMS, i.e. MECHANISMS PRINTING OTHERWISE THAN FROM A FORME; CORRECTION OF TYPOGRAPHICAL ERRORS
- B41J2/00—Typewriters or selective printing mechanisms characterised by the printing or marking process for which they are designed
- B41J2/005—Typewriters or selective printing mechanisms characterised by the printing or marking process for which they are designed characterised by bringing liquid or particles selectively into contact with a printing material
- B41J2/01—Ink jet
- B41J2/17—Ink jet characterised by ink handling
- B41J2/175—Ink supply systems ; Circuit parts therefor
- B41J2/17593—Supplying ink in a solid state
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B41—PRINTING; LINING MACHINES; TYPEWRITERS; STAMPS
- B41J—TYPEWRITERS; SELECTIVE PRINTING MECHANISMS, i.e. MECHANISMS PRINTING OTHERWISE THAN FROM A FORME; CORRECTION OF TYPOGRAPHICAL ERRORS
- B41J2/00—Typewriters or selective printing mechanisms characterised by the printing or marking process for which they are designed
- B41J2/005—Typewriters or selective printing mechanisms characterised by the printing or marking process for which they are designed characterised by bringing liquid or particles selectively into contact with a printing material
- B41J2/01—Ink jet
- B41J2/015—Ink jet characterised by the jet generation process
- B41J2/04—Ink jet characterised by the jet generation process generating single droplets or particles on demand
- B41J2/06—Ink jet characterised by the jet generation process generating single droplets or particles on demand by electric or magnetic field
- B41J2002/061—Ejection by electric field of ink or of toner particles contained in ink
Landscapes
- Ink Jet Recording Methods And Recording Media Thereof (AREA)
- Particle Formation And Scattering Control In Inkjet Printers (AREA)
- Inks, Pencil-Leads, Or Crayons (AREA)
- Ink Jet (AREA)
- Pharmaceuticals Containing Other Organic And Inorganic Compounds (AREA)
- Application Of Or Painting With Fluid Materials (AREA)
Abstract
An apparatus and a method for the formation of droplets from meltable powdered solid or highly viscous materials such as inks (9) by reducing the viscosity (10, 14) of the material to a viscosity to enable droplet formation, providing the reduced viscosity ink to an ejection location (6), applying a constant or pulsed electrical potential (4) to the ejection location to form an electric field at the location and ejecting such droplets away from the ejection location by electrostatic means. Alternatively there may be constant electrical potential to form a constant electrostatic field at the ejection location and pulsed heating of the ejection location.
Description
WO 94118011 215 5 9 ~ 2 PCT/AUS14/0006!i METHOD AND APPARATUS FOR THE PRODUCTION OF DROPLETS
TECHNIC~I FIEI n This invention relates to a method and apparatus for the production of droplets of material from a solid, powdered or highly viscous meltable material.
10 BAcKGRouNn ART
One particular :1" ' " 1 to which this invention may be applied is the transfer of droplets of high intensity colouring materials to a recording surface for the purpose of non-impact printing. It is to be u, ,de,~tuod, 15 however, that the invention is not limited to delivering coloured materials for the purpose of non-impact printing but may be used to generate droplets of materials in general or to deposit other materials in a defined pattem on a substrate. Examples of other ", ' ,s are the deposition of pl1o~ ,s or fluoro pl1O:,,ull~la for security coding, 20 hot melt adhesives and ~,upelld"'l~ aerosols. The invention may also be used for the ,u, uf~llal ," - production and ejection of particulate l~l1a~ A~,I' ' in a pl,a""ac~utically ~Cf ~ meltable carrier.
25 This invention, however, will be discussed in relation to its ,, " "
to printing but as indicated its scope is broader than this.
There are a number of different forms of equipment used for the non-impact printing systems which are generally referred to as ink jet 30 printing. It is usual for ink to be fed through a nozzle, the exit diameter of which nozzle being a major factor in d~,"..lllillillg the droplet size and hence the size of the resulUng dots on a recording surface. The droplets may be produced from the nozzle either continuously in which case the method is termed continuous printing or they may be 35 produced individually as required in which case the method is termed drop-on-demand printing. In continuous printing an ink is delivered through the nozzle at high pressure and the pressure at the nozzle is perturbed at a s~L:,ld" lly constant frequency which results in a stream of droplets of constant size. By applying charge to the droplets _ _ _ _ _ _ _ . .... _ _ J ~.
and using an electric field external to the nozzle selected droplets may be deflected in their passage to the recording surface in response to a signal effecting the electric field whereby forming a pattern on the recording surface in response to the control signal. Drop-on-5 demand printing operates by producing local pressure pulses in theliquid in the vicinity of a small nozzle which results in a droplet of liquid being ejected from the nozzle at a selected time.
In either type of jet printing the colouring material is a soluble dye 10 combined with binders to render the printed image more pe""d"~"l in a liquid carrier.
The disadvantage of soluble dyes is that the printed image density is not high enough in many ._. ~s and that the dyes fade under 15 exposure in the env; JI l~ . A further disadvantage with soluble dye materials is that the quality of the printed image is d~.e(,cle, ll on the properties of the recording surface.
Pi~ d inks are known to produce higher density images than 20 soluble dyes and are also more pe~ dll~ Pigments may also be used in jet printers along with a carrier liquid but the production of a dense image requires a high con~" ..:i ." of pigment material in the carrier liquid. The high ~u, ICt:" 1 of pigment material affects the droplet breakup in continuous printers and results in less unifomm 25 printing. Drop-on-demand printers do not have a high continuous pressure and the droplet y~"e, ~ is strongly depellde"l on local conditions in the nozzle therefore the presence of pigments can modify the local nozzle conditions or block the nozzle such that droplets are not correctly ejected.
A further process known as ele~.l,u~lc,tic ink jet printing is ~:lldldut~ ed by an ~le~:t,, - pull on a liquid and is disclosed in for instance US Patent 3 060 429. This involves the yelle,c.liùn and accele, l of charged droplets from a nozzle cul l ,i"y the liquid to 35 a platen electrode by a high voltage being ",~;.,tdi"ed between the nozzle and the platen. This process is further optimised by including a valving electrode that is used to interrupt or control the jet flow as well as two pairs of ele~ l,udes used to manipulate the flight path of the WO 94118011 21 ~ ~ 9 ~ 2 PCT/AU94/00065 droplets. Printing is achieved by locating a paper substrate just prior to the platen electrode and using a conductive solution of ink.
It has been proposed such as in US Patent No. 3 653 932 to use an 5 ink which is solid at room temperature but to melt it in a heating tank before supplying it to a nozzle before subsequent drawing across a gap to a substrate by means of a high voltage. This system and apparatus has the disadvantage of u~ ceaaaly c vlllpl~Aity of setting the voltage di~ "~es between the nozzle and a valving electrode 10 and then between the valving electrode and a platen i,,c~,~,v, ,9 the substrate upon which printing is to be done. A similar ar,d,-yerll~ is described in a published article in IS&Ts Eighth ll Ill' ,al Congress on Advances in Norl-lmpact Printing Te..l",~loyies (1992) pages 334 - 339.
It is an object of this invention to provide a method and apparatus fordroplet fommation from meltable powdered solid or highly viscous materials such as inks in which the droplets are not produced by a nozzle and hence the size of the droplets are not affected by the size of 20 the nozzle.
It is a further object of this invention to provide a method and apparatus for droplet formation from meltable powdered solid or highly viscous materials such as inks with a high conce, ItlatiVII of pigment or other 25 solid materials so that high intensity images can be provided onto a recording surface or droplets with relatively large amounts of solid materials can be produced.
It is a further object of this invention to produce a method and 30 apparatus for droplet formation from meltable powdered solid or highly viscous materials such as inks including a carrier or using a carrier which is not l1ecessdlily conductive.
DISCLOSURE OF THE INVFNTION
In one form therefore the invention is said to reside in a method of formation of droplets from a meltable powdered solid or highly viscous material c~""~,riai, ,9 the steps of reducing the viscosity of the material to a viscosity which will enab~e droplet formation providing the _ _ . . . _ . _ - ~R~E'CEI~E~ 12 ~ ~E~ ~g94' . ,, 215~;942 reduced viscosity material to an ejection point, applying an electrical potenhal to the ejection point to form an electric field at the point and thereby causing the reduced viscosity material to form droplets on the ejection point and ejecting such droplets away from the ejection point 5 by ~ . means.
The powdered, solid or highly viscous material may be an ink cu"",-i:,i"g a colourant and a carrier. The colourant may be a pigment.
10 The viscosity may be reduced by heating or by pressure.
It will be seen that by this invention the size of the droplets of the material such as an ink is not d~.dl)de"l upon the size of any nozzle which delivers the reduced viscosity material to the ejection point but is 15 dependd,ll upon the ejection point geometry, the level of the electrical field, the amount of heating at the ejection point and the nature of the reduced viscosity material such as an ink and its viscosity at the time of ejection.
20 It can also be seen that the present invention differs from the prior art in that the reduced viscosity material such as an ink does not necessd,ily include a conductive carrier liquid at the time of droplet formation.
Droplets appear to be formed by ~le~ - means acting upon the particles of solid such as a pigment within the reduced viscosity 25 material such as an ink. The liquid portion acts solely as a carrier. The transfer of pigment instead of liquid solutions of colouring matter means that a more intense image can be formed on a substrate and a finer dot size can be formed with a quicker setting dot.
30 In one preferred form of the invention the electrical potential forming the field may be pulsed so that there is periodic formation and ejection of droplets from the ejection point.
The electrical potential will cause an electric field to build at the 35 ejection point and may be d~dl ,de"l upon the geometry of the ejection point such as the radius of curvature of the ejection point and in a preferred e",~odi",~"l of the invention the ejection point may be provided by a needle having a radius of curvature at its tip in the range of 5-50 microns. AII~ .';JCIY the ejection point may be provided by an AMENDED SHEET
IpEA/AU
PCI~/AU 9 4 7 0 0 0 6 21~942 RECE~I~E~ 2 3 OEC l9~, elongate sharpened edge. There may be a number of ejection points along bhe elongate edge or there may be a matrix of ejection points.
The method of this invention may produce droplets of the material such 5 as an ink in a size range of 1 micron to 500 microns in diameter or even larger depel1ui,,g upon the geometry of the ejection point, viscosity, type of carrier included in the material and voltage applied.
Preferably the carrier portion of the material is a non-ele~l,ic~:ly 10 conducting liquid when in the reduced viscosity state and the solid material such as a pigment within bhe ink is c~"",,i:,ed of ~I,a,y~dL,le particles. Preferably the .:l ,a, yed~le particles may be charged to the same polarity as the voltage applied to the ejecbon point.
15 The electrical potential applied to the ejection point may be in the range of 500 to 6000 volts or higher.
In an dlt~lll .1~, form the invention may be said to reside in an apparatus for ~ e,dliu~ of droplets of a material from a meltable 20 powdered, solid or highly viscous material cc""~ ,i,lg means to reduce the viscosity of the powdered, solid or highly viscous material to a viscosity which will enable droplet formation, means to supply the reduced viscosity material to an ejection point, and means to apply an electrical potenbal to the ejecbon point to form an electrical field at the 25 ejection point whereby to enable formation and ejecbon of droplets of the material from the ejection point.
Once again the powdered, solid or highly viscous material may be an ink cr.",~ i, Ig a colourant and a carrier the colourant may be a 30 pigment.
The viscosity may be reduced by heating or by pressure.
It will be seen that by this form of the invenbon an apparatus is 35 provided which will enable droplets of a meltable powdered, solid or highly viscous material to be produced and ejected from bhe ejection point.
AMENDED SHEE~
IPEA/AU
PRcErcAE I V E3 /2 ~ ~)E~? t~`
6 215~9~2 The means to supply a flow of reduced viscosity material to the ejecUon point may be provided by various means depe~i"g upon the original nature of the material.
5 In the case of a solid meltable material there may be a spring loaded chamber containing pellets or a stick of the meltable material which at an end nearest the ejection point includes a heating means adapted to melt the meltable material to the required viscosity. All~ cly there may be two stage heating with the first stage adapted to soften the 10 meltable material to such a viscosity that it can be forced under the spring pressure to a second stage heater which reduces the viscosity - for the meltable material to the final required viscosity. With certain inks it has been found that if they are contained in a vertical closed vessel, two stage heating, aided by the force of gravity and/or the 15 expansion of the material upon heating facilitates both viscosity reduction and feed to the ejection point.
Such heaters may be of the resistance type or so called induction type.
20 The resistance type of heater may be a resistance wire wound around a receptacle for the material.
The induction type consists of a coil wound about a ferrite core which is jllYt~posed with respect to the vessel containing the ink.
25 Allt7ll, .I~,'y the coil may be wound about the vessel wherein the said vessel acts as the core, directly heating the ink.
The ejection point may also be heated to maintain the required viscosity of the ink.
Such heating of the ejection point may be constant or pulsed. The heating of the ejection point may be a point source heater such as an infrared laser diode.
35 In the case of a powdered ink a powder feeder may be used to supply powder to the heahng stage where it is melted in either one or two stages to a required viscosity for ejection.
AMEN~ED SHEEr __ , PCI~/AU 9 4 / O O 0 6 ~
RECEIVED 2 3 DEC t994 In the case of a highly viscous ink this rnay be supplied in a cartridge 215 5 9 4 2 with a spring loaded piston at one end. The spring pressure is adapted to push the paste-like or treacle-like ink directly to the heating chamber.
The ink may be composed of a low melting point wax or resin combined with a pigment phase. Examples of these materials include AC6, a polyethylene wax made by Allied Sinal; Elvax 210, an ethylene vinyl acetate resin made by Du Pont:; Syntha Wax, a hydluy~ d 10 castor oil made by Lever and Kitchen; Paraffin wax, made by Exxon and mixtures thereof. The pigment may be selected from any of a range of pigments dependi"g upon the colour required. Examples of pigments include organic pigments such as Irgalite Blue LGLD, a Pigment Blue 15:3 made by Ciba Geigy: Microlith Black CT, a Pigment 15 Black 7 made by Ciba-Geigy: Monolite Yellow GNA, a Pigment Yellow 1 made by ICI or inorganic pigments such as silicas, metallics or magnetic iron oxides.
Viscosity of inks may be optimised or pre-disposed for droplet 20 fommation. This may be achieved by controlling the temperature of the heating points or , - ~ 'Iy at the ejection point. Viscosity of the ink may be changed by the addition of a viscosity control agent such as Energol WM2, a paraffin oil made by BP Chemicals, or the like.
25 In one form the ejection point may be provided by a needle point having a radius of curvature of from 5 to 50 microns or the ejection point may be provided by an elongate edge having a semi-cylindrical surface having a radius of curvature of 5 to 50 microns. A' " ~loly the ejection point may comprise a matrix of ejection points.
The apparatus according to this invention may be adapted to provide droplets on demand or to provide a continuous stream of droplets which can be deflected by ele~it,~ means external to the ~Jptll 1~ The supply of droplets on demand may be provided by 35 providing a pulséd electrical potential or pulsed heating to the ejection point.
This peliodi~:ly applied potential may be of any waveform which allows consistent ejection of droplets from the ejection point. Preferred AMENDED SHEEr PC~iAU g 4 / O ~ 0 6 -RECEIVED 2 3 OEC l99i ~vc.v~""s include square waves and puises which may have an 21~ 5 g ~ 2 offset or threshold potential.
The electrical potential applied to the ejection point may be in the range of +500 to +5000 volts. A" " ' v~ly the electrical potential applied to the ejection point may comprise a constant bhreshold in the range of +500 to +5000 volts and a pulsed voltage of up to + 800 volts.
Pulsed heating may be provided by a solid state infrared laser diode to provide a point source of heating at the ejection point.
Such a heating device may exhibit specific properties such as fast switching time, ap~ ' heat output with respect to wavelength, bandwidth and heating power for melting the material such as the material, and suitable spot size wibh respect to the ~i",~,~sio,~s of the ejection point.
Generally it can be seen that this invention provides droplet formation at an ejection point and the el~u1,~ ejecbon of such droplets.
Although the ",e~;l Idl lialll for operation of the droplet formation is not fully u"de,:,~uod one theory, to which bhe applicants are not ,1ecessd,ily bound, is as follows: Particles in the reduced viscosity material flowing to the ejection point are inherently charged or charged to the same polarity as the ejection point. More and more particles continue to build up on the ejection point within a forming droplet of the carrier liquid of the material and with increasing repulsion the particles tend to move away from bhe ejection point until ele.;b~ ' ' repulsion between bhe ejection point and the forming droplet of the charged particles builds up to such an extent that surface tension of the entrained carrier liquid can no longer hold the droplet to the ejecbon point. At this stage bhe droplet is repulsed by ele.,l,~ " means.
It may be particularly noted that because the repulsion is subaldl~ l'y ele~;t,~ no earthed substrate is necessary to attract bhe droplets to a substrate and in fact cu"~ ,dble distances of droplet flight can occur before they impinge a substrate. This enables suitable ~le~lualdliu or obher forms of deflection equipment to provide whatever patterning of droplets is required on a substrate.
AMENDED SHEEr IPEA/AU
P~/AU y 4 / ~ O 0 6 _ RECEIVEO 2 3 DEC f994 9 21~94~
The a~ r,l may include a pair of ejection points each producing droplets of one cu, l l~Jo"~l ll of a two col l l~.vl~ adhesive system This would provide an adhesive ~ gun.
This then generally describes the invention but to assist in ulld~ illg the invention reference will now be made to the accvllllJallying drawings which show a preferred ~Illbv~illlelll of the invention and illustrates a II,eo,~.:;c,al action of the invention.
g~lFF ~ESCRIPTION OFDRAWINGS
In the drawings:
15 FIG. 1 shows a sectional view of droplet formation apparatus of an L,Odil l lel 11 of the invention;
FIG. 2 shows a sectional view of an -' -ll ic elllbodil"~ of a droplet formation ~rp~r~tl Ic and FIG. 3 shows a sectional view of a further " I ,1~ ~ll ,I,o.li"~"l of adroplet formation apparatus.
DESCRIPTION OF THE PRE~R~I ) E~ ~nO~ 'T
FIG. 1 illustrates the one ~IllI,cldi~ lll of the invention for use in forming droplets of an ink.
The apparatus for 9~"t:~.'k~" of discrete droplets from a solid ink 30 consists of a body 1 which may be of an insulaUng material fashioned to a tapered point. Extending from the body is a hollow tube 2 of an electrical and thermal conducting material which is ~le~ llJ charged by electrical conductor 3 extending from a power source 4. The ejecUon point 6 is formed at a tip of the tube 2 and is of a selected 35 radius of curvature, in this case a spherical point. The body has an aperture 7 extending through it to the tube 2. The aperture 7 is comprised of a first portion 8 of a first diameter, adapted to receive a stick 9 of a solid ink. A heating coil 10 around the first portion 8 provides heating to soften the stick of ink g to such an extent that AMENDED 8HEEr IPEA~AU
PCI~/AU y 4 / O ~ 0 6 RECEIVE~ 2 3 DEC ~994 spring 11 can e%tnude the ink through a tapered portion 12 of the 21 ~ ~ 9 ~ 2 aperture 7 into a second portion 13 of reduced diameter. In this second portion 13 a further heating coil 14 provides heating to further melt the ink until it is at a viscosity to enable flow to the ejection point 5 under the pressure supplied by spring 11 and droplet formation. At the ejection point the ~ o~ldli~ charge causes droplet formation as discussed earlier.
FIG. 2 illustrates another ~",bo~i",~r,~ of the apparatus for gelleldliun 10 of discrete droplets from a solid ink. Those parts which are the same as in FIG. 1 have the same reference numerals.
A body 1 which may be of an insulating material is fashioned to a tapered point. Extending from the body is a tube 2 of a thermally and 15 el~-,t, 'Iy conducting material which is eleut,i~.:ly charged by electrical conductor 3 e%tending from a power source 4. The ejection point 6 is at the tip of the tube 2 and tapers to a point of a selected radius of curvature, in this case a spherical point. The body has a hollow aperture 7 e%tending through it to the tube 2 and the ejection 20 point 6. The aperture 7 is adapted to receive a stick g of a solid ink. A
heating coil 10 around the aperture 7 softens and expands the ink 9 extruding said ink through aperture 7 into the tube 2 such that ink of the correct viscosity to allow droplet formation flows to the ejection point 6 under pressure. At the ejection point the ele~:,ldli~ charge 25 causes droplet formation as discussed earlier. A plug 15 closes off the end of the aperture 7 remote from the tube 2 to enable pressure formed by expansion of the meltable ink on melting to direct ink to the ejection point 6.
3û FIG. 3 illustrates yet another ~",bodi",~"l of the apparatus for ytsllel dliol1 of discrete droplets from a solid ink. Those parts which are the same as in FIG. 1 have the same reference numerals.
A body 1 which may be of an insulating material fashioned to a 35 tapered point. Extending from the body is a hollow tube 2 of a thermally and ~lecl,ki.~lly conducting material which is eleul,i~
charged by electrical conductor 3 extending from a power source 4.
The ejection point 6 is formed at a tip of the tube 2 which tapers to a point on one edge of the tube of a selected radius of curvature, in this AMENDED SHEET
IP~AU
, . ---- _ . . ..
~CI/AU y 4 ¦ U U U
RECEIVE~ 2 3 DEC 199 11 21 ~9~2 case a spherical point. The body has an aperture 7 extending through it to the tube 2. The aperture 7 is c~, I IlJ, i~ed of first portion 8 of a first diameter adapted to receive a stick 9 of a solid ink. A heating coil 10 around the first portion 8 provides heating to soften the stick of ink 9 to such an extent that spring 11 can extrude the ink through the tapered portion 12 of the aperture 7 into a second portion 13 of reduced diameter and into the tube 2. Further heating is provided by an infrared solid state laser diode 16 and an optical fibre 17 directed to the tube 2. This provides heat which further melts the ink until it is at a viscosity to flow to the ejection point and to enable formation of droplets. At the ejection point the eleutl. charge causes droplet formation, as discussed earlier, when the viscosity has been reduced by the heat from the infrared solid state laser diode 16 via the optical fibre 17. This heating may be pulsed to enable selected or pulsed formation and ejection of droplets.
Examples of operation of droplet formation according to this invention are given in the following examples 1 to 6.
In these examples an ink was provided by blending 999 of Syntha Wax (a h~ilugt:ll castor oil) and 19 of Pigment Blue 15 which were placed into a heated attritor milling device and heated to 1 50C to affect the melting of the Il ,~", lO,UId::~ti;: materials. After milling for 6 hours, the molten ink was removed from the attritor and allowed to solidify by cooling.
Viscosity of this ink at an op~- Idl temperature to allow droplet formation was 10 mPa.s.
EY~mple 1 This ink was placed in the apparatus as described with reference to the ~",L,o~ii",e";~ shown in FIG 1. with bond paper placed 20mm from the single point ejection point with a radius of curvature of 25 microns.
Excellent results were obtained when the ejection point was at 135 C
and + 600 volt pulses were applied at 5000 Hz on top of the threshold potential of +1500 volts. Printed drop size was 10 microns with excellent colour density and integrity.
ANiENDED SHEET
PCI/AU ~ 4 / U O 0 6 RECEt~ED 2 3 DEC 19 12 21 5~9 42 Example 2 This ink was placed in the apparatus as described in FIG 1. with bond paper placed 20mm from the single point ejection point with a radius of curvature of 25 microns. Excellent results were obtained when the 5 ejection point was at 135 C and +800 volt pulses were applied at 5000 Hz on top of the threshold potential of +2000 volts. Printed drop size was 20 microns with excellent colour density and integrity.
Fx~mple 3 10 This ink was placed in the apparatus as described in FIG 1. with bond paper placed 1 Omm from the single point ejection point with a radius of curvature of 25 microns. Excellent results were obtained when the ejection point was at 135 C and +600 volt pulses were applied at 5000 Hz on top of the threshold potential of +1500 volts. Printed drop size 15 was 70 microns with excellent colour density and integrity.
EYArnple 4 This ink was placed in the apparatus as described in FIG 1. with bond paper placed 1 Omm from the single point ejection point with a radius of 20 curvature of 25 microns. Excellent results were obtained when the ejection point was at 135 C and +800 volt pulses were applied at 5000 Hz on top of the threshold potential of +2000 volts. Printed drop size was 150 microns with excellent colour density and integrity.
25 FY~Ie 5 This ink was placed in the apparatus as described in FIG 1. with bond paper placed 5mm from the single point ejection point with a radius of curvatu~e of 25 microns. Excellent results were obtained when the ejection point was at 135 C and +600 volt pulses were applied at 5000 30 Hz on top of the threshold potential of +1500 volts. Printed drop size was 150 microns with excellent colour density and integrity.
AMENDED SHEEr IPEVAU
PCrIAU 9 4 / O O 0 6 -RECEIVED 2 3 DEC 19n' 13 21 559~2 FY~rr~ple 6 This ink was placed in the apparatus as described in FIG 1. with bond paper placed 5mm from the single point ejection point with a radius of curvature of 25 microns. Excellent results were obtained when the ejecbon point was at 135 C and +800 volt pulses were applied at 5000 Hz on top of the threshold potential of +2000 volts. Printed drop size was 300 microns with excellent colour density and integrity.
The Examples 7 to 13 illustrate droplet formation according to the method and apparatus of this invention with other inks. These inks were manufactured by the method as disclosed in previous examples.
All viscosity measurements in these examples were performed on a Haake IlI,eu", '~.. Rheostress RS100.
15 FY~rnlple 7 Paramn Wax 439 Irgalite Blue LGLD 49 20 Viscosity of this ink at ùpt~ k~lldl L~"l,ue, ~re was 45 mPa.s The ink was placed in the apparatus as described with reference to the ~,nl,o~i",t r,l shown in FIG 1. with bûnd paper placed 10mm from a single point ejection point with a radius of curvature of 25 microns.
25 Excellent results were obtained when the ejection point was at 135 C
and +800 volt pulses were applied at 5000 Hz on top of the threshold potential of +2000 volts. The printed drop had excellent colour density and integrity.
30FY~rnvle 8 Paramn Wax 809 Elvax 210 99 Irgalite Blue LGLD 49 35 Viscosity of this ink at o~, )ndl temperature was 32 mPa.s The ink was placed in the apparatus as described with reference to the ~:"lbo~i",~"l shown in FIG 1. with bond paper placed 1 0mm from the single point ejection point with a radius of curvature of 25 microns.
AMENDED SHEET
, IPE4/AU
RECE18ED 2~ ~EQC ~5 Excellent results were obtained when the ejection point was at 135 C 21~ ~ 9 4 2 and +800 volt pulses were applied at 5000 Hz on top of the threshold potential of +2000 volts. The printed drop had excellent colour density and integrity.
FY~rnple 9 Paraffin Wax 809 Elvax 210 99 Energol WM2 209 10Irgalite Blue LGLD 49 Viscosity of this ink at ~.el Idl ~ Ires was 15 mPa.s.
The ink was placed in the apparatus as described with reference to the 15 e",L,odi",~"l shown in FIG. 1 with bond paper placed 1Omm from the single point ejection point with a radius of curvature of 25 microns.
Excellent results were obtained when the ejection point was at 135C
and +800 volt pulses were applied at 5000 Hz on top of the threshold potential of +2000 volts. The printed drop had excellent colour density 20and integrity.
EY~rnple 10 Paraffin Wax 499 AC6 49g 25Irgalite Blue LGLD 19 Viscosity of this ink at CJ~61 " lal temperature was 31 mPa.s.
The ink was placed in the apparatus as described with reference to the 30 ~Illbo~ l shown in FIG. 1 with bond paper placed 10mm from the single point ejection point with a radius of curvature of 25 microns.
Excellent results were obtained when the ejection point was at 135 C
and +800 volt pulses were applied at 5000 Hz on top of the threshold potential of +2000 volts. The printed drop had excellent colour density.
AMENDED SHEEr IPEA/AU
PC~/AU 9 4 / O O ~ 6 RECElVEa 2 3 DEC ~9 Example 11 15 21$S9~2 Paraffin Wax 99g Microlith Black CT 19 5 Viscositv of this ink at ~, dIiu11dl temperature was 2.5 mPa.s.
The ink was placed in the apparatus as described with reference to the ~" ,IJ~d;, I ,er,L shown in FIG. 1 with bond paper placed 1 Omm from the single point ejection point with a radius of curvature of 25 microns.
10 The ejection point was at 1 35C and +800 volt pulses were applied at 5000 Hz on top of the threshold potential of +2000 volts. The printed drop had poor colour densitv and integrit~v.
EY~ le 12 15 Pardffln Wax 999 Monolite Yellow GNA 19 Viscosit~v of this ink at u~uel ,al temperature was 13 mPa.s.
20 The ink was placed in the apparatus as described with reference to the ~"lbodi",t:"l shown in FIG. 1 with bond paper placed 10mm from the single point ejection point with a radius of curvature of 25 microns.
The ejection point was at 135C and +800 volt pulses were applied at 5000 Hz on top of the threshold potential of +2000 volts. The printed 25 drop had poor colour densitv and integritv.
FY~rn~le 13 Paraffin Wax 439 Irgalite Blue LGLD 19 Viscositv of this ink at o~.e, _ ~dl temperature was 45 mPa.s.
The ink was placed in the apparatus as described with reference to the 35 ~"l~o,li",~"l shown in FIG. 3 with bond paper placed 10mm from the single point ejection point with a radius of curvature of 25 microns.
Excellent results were obtained when the ejection point was at 135C
and the laser was modulated at 5000 Hz. A potential of +2800 volts AMENDED SHEEr IPE 4tAU
Pcr/AV ~4 / ~nn 6 .
RECEI V ED 2 3 ~C -~9~
was applied to the ejection point. The printed drop had an excellent 21 ~ S 9 ~ 2 colour density and integrity.
It will be seen that by this invention there is provided a simple method 5 and apparatus by which droplets of a meltable solid, powdered or highly viscous material such as an ink may be produced.
AMENDED SHEET
TECHNIC~I FIEI n This invention relates to a method and apparatus for the production of droplets of material from a solid, powdered or highly viscous meltable material.
10 BAcKGRouNn ART
One particular :1" ' " 1 to which this invention may be applied is the transfer of droplets of high intensity colouring materials to a recording surface for the purpose of non-impact printing. It is to be u, ,de,~tuod, 15 however, that the invention is not limited to delivering coloured materials for the purpose of non-impact printing but may be used to generate droplets of materials in general or to deposit other materials in a defined pattem on a substrate. Examples of other ", ' ,s are the deposition of pl1o~ ,s or fluoro pl1O:,,ull~la for security coding, 20 hot melt adhesives and ~,upelld"'l~ aerosols. The invention may also be used for the ,u, uf~llal ," - production and ejection of particulate l~l1a~ A~,I' ' in a pl,a""ac~utically ~Cf ~ meltable carrier.
25 This invention, however, will be discussed in relation to its ,, " "
to printing but as indicated its scope is broader than this.
There are a number of different forms of equipment used for the non-impact printing systems which are generally referred to as ink jet 30 printing. It is usual for ink to be fed through a nozzle, the exit diameter of which nozzle being a major factor in d~,"..lllillillg the droplet size and hence the size of the resulUng dots on a recording surface. The droplets may be produced from the nozzle either continuously in which case the method is termed continuous printing or they may be 35 produced individually as required in which case the method is termed drop-on-demand printing. In continuous printing an ink is delivered through the nozzle at high pressure and the pressure at the nozzle is perturbed at a s~L:,ld" lly constant frequency which results in a stream of droplets of constant size. By applying charge to the droplets _ _ _ _ _ _ _ . .... _ _ J ~.
and using an electric field external to the nozzle selected droplets may be deflected in their passage to the recording surface in response to a signal effecting the electric field whereby forming a pattern on the recording surface in response to the control signal. Drop-on-5 demand printing operates by producing local pressure pulses in theliquid in the vicinity of a small nozzle which results in a droplet of liquid being ejected from the nozzle at a selected time.
In either type of jet printing the colouring material is a soluble dye 10 combined with binders to render the printed image more pe""d"~"l in a liquid carrier.
The disadvantage of soluble dyes is that the printed image density is not high enough in many ._. ~s and that the dyes fade under 15 exposure in the env; JI l~ . A further disadvantage with soluble dye materials is that the quality of the printed image is d~.e(,cle, ll on the properties of the recording surface.
Pi~ d inks are known to produce higher density images than 20 soluble dyes and are also more pe~ dll~ Pigments may also be used in jet printers along with a carrier liquid but the production of a dense image requires a high con~" ..:i ." of pigment material in the carrier liquid. The high ~u, ICt:" 1 of pigment material affects the droplet breakup in continuous printers and results in less unifomm 25 printing. Drop-on-demand printers do not have a high continuous pressure and the droplet y~"e, ~ is strongly depellde"l on local conditions in the nozzle therefore the presence of pigments can modify the local nozzle conditions or block the nozzle such that droplets are not correctly ejected.
A further process known as ele~.l,u~lc,tic ink jet printing is ~:lldldut~ ed by an ~le~:t,, - pull on a liquid and is disclosed in for instance US Patent 3 060 429. This involves the yelle,c.liùn and accele, l of charged droplets from a nozzle cul l ,i"y the liquid to 35 a platen electrode by a high voltage being ",~;.,tdi"ed between the nozzle and the platen. This process is further optimised by including a valving electrode that is used to interrupt or control the jet flow as well as two pairs of ele~ l,udes used to manipulate the flight path of the WO 94118011 21 ~ ~ 9 ~ 2 PCT/AU94/00065 droplets. Printing is achieved by locating a paper substrate just prior to the platen electrode and using a conductive solution of ink.
It has been proposed such as in US Patent No. 3 653 932 to use an 5 ink which is solid at room temperature but to melt it in a heating tank before supplying it to a nozzle before subsequent drawing across a gap to a substrate by means of a high voltage. This system and apparatus has the disadvantage of u~ ceaaaly c vlllpl~Aity of setting the voltage di~ "~es between the nozzle and a valving electrode 10 and then between the valving electrode and a platen i,,c~,~,v, ,9 the substrate upon which printing is to be done. A similar ar,d,-yerll~ is described in a published article in IS&Ts Eighth ll Ill' ,al Congress on Advances in Norl-lmpact Printing Te..l",~loyies (1992) pages 334 - 339.
It is an object of this invention to provide a method and apparatus fordroplet fommation from meltable powdered solid or highly viscous materials such as inks in which the droplets are not produced by a nozzle and hence the size of the droplets are not affected by the size of 20 the nozzle.
It is a further object of this invention to provide a method and apparatus for droplet formation from meltable powdered solid or highly viscous materials such as inks with a high conce, ItlatiVII of pigment or other 25 solid materials so that high intensity images can be provided onto a recording surface or droplets with relatively large amounts of solid materials can be produced.
It is a further object of this invention to produce a method and 30 apparatus for droplet formation from meltable powdered solid or highly viscous materials such as inks including a carrier or using a carrier which is not l1ecessdlily conductive.
DISCLOSURE OF THE INVFNTION
In one form therefore the invention is said to reside in a method of formation of droplets from a meltable powdered solid or highly viscous material c~""~,riai, ,9 the steps of reducing the viscosity of the material to a viscosity which will enab~e droplet formation providing the _ _ . . . _ . _ - ~R~E'CEI~E~ 12 ~ ~E~ ~g94' . ,, 215~;942 reduced viscosity material to an ejection point, applying an electrical potenhal to the ejection point to form an electric field at the point and thereby causing the reduced viscosity material to form droplets on the ejection point and ejecting such droplets away from the ejection point 5 by ~ . means.
The powdered, solid or highly viscous material may be an ink cu"",-i:,i"g a colourant and a carrier. The colourant may be a pigment.
10 The viscosity may be reduced by heating or by pressure.
It will be seen that by this invention the size of the droplets of the material such as an ink is not d~.dl)de"l upon the size of any nozzle which delivers the reduced viscosity material to the ejection point but is 15 dependd,ll upon the ejection point geometry, the level of the electrical field, the amount of heating at the ejection point and the nature of the reduced viscosity material such as an ink and its viscosity at the time of ejection.
20 It can also be seen that the present invention differs from the prior art in that the reduced viscosity material such as an ink does not necessd,ily include a conductive carrier liquid at the time of droplet formation.
Droplets appear to be formed by ~le~ - means acting upon the particles of solid such as a pigment within the reduced viscosity 25 material such as an ink. The liquid portion acts solely as a carrier. The transfer of pigment instead of liquid solutions of colouring matter means that a more intense image can be formed on a substrate and a finer dot size can be formed with a quicker setting dot.
30 In one preferred form of the invention the electrical potential forming the field may be pulsed so that there is periodic formation and ejection of droplets from the ejection point.
The electrical potential will cause an electric field to build at the 35 ejection point and may be d~dl ,de"l upon the geometry of the ejection point such as the radius of curvature of the ejection point and in a preferred e",~odi",~"l of the invention the ejection point may be provided by a needle having a radius of curvature at its tip in the range of 5-50 microns. AII~ .';JCIY the ejection point may be provided by an AMENDED SHEET
IpEA/AU
PCI~/AU 9 4 7 0 0 0 6 21~942 RECE~I~E~ 2 3 OEC l9~, elongate sharpened edge. There may be a number of ejection points along bhe elongate edge or there may be a matrix of ejection points.
The method of this invention may produce droplets of the material such 5 as an ink in a size range of 1 micron to 500 microns in diameter or even larger depel1ui,,g upon the geometry of the ejection point, viscosity, type of carrier included in the material and voltage applied.
Preferably the carrier portion of the material is a non-ele~l,ic~:ly 10 conducting liquid when in the reduced viscosity state and the solid material such as a pigment within bhe ink is c~"",,i:,ed of ~I,a,y~dL,le particles. Preferably the .:l ,a, yed~le particles may be charged to the same polarity as the voltage applied to the ejecbon point.
15 The electrical potential applied to the ejection point may be in the range of 500 to 6000 volts or higher.
In an dlt~lll .1~, form the invention may be said to reside in an apparatus for ~ e,dliu~ of droplets of a material from a meltable 20 powdered, solid or highly viscous material cc""~ ,i,lg means to reduce the viscosity of the powdered, solid or highly viscous material to a viscosity which will enable droplet formation, means to supply the reduced viscosity material to an ejection point, and means to apply an electrical potenbal to the ejecbon point to form an electrical field at the 25 ejection point whereby to enable formation and ejecbon of droplets of the material from the ejection point.
Once again the powdered, solid or highly viscous material may be an ink cr.",~ i, Ig a colourant and a carrier the colourant may be a 30 pigment.
The viscosity may be reduced by heating or by pressure.
It will be seen that by this form of the invenbon an apparatus is 35 provided which will enable droplets of a meltable powdered, solid or highly viscous material to be produced and ejected from bhe ejection point.
AMENDED SHEE~
IPEA/AU
PRcErcAE I V E3 /2 ~ ~)E~? t~`
6 215~9~2 The means to supply a flow of reduced viscosity material to the ejecUon point may be provided by various means depe~i"g upon the original nature of the material.
5 In the case of a solid meltable material there may be a spring loaded chamber containing pellets or a stick of the meltable material which at an end nearest the ejection point includes a heating means adapted to melt the meltable material to the required viscosity. All~ cly there may be two stage heating with the first stage adapted to soften the 10 meltable material to such a viscosity that it can be forced under the spring pressure to a second stage heater which reduces the viscosity - for the meltable material to the final required viscosity. With certain inks it has been found that if they are contained in a vertical closed vessel, two stage heating, aided by the force of gravity and/or the 15 expansion of the material upon heating facilitates both viscosity reduction and feed to the ejection point.
Such heaters may be of the resistance type or so called induction type.
20 The resistance type of heater may be a resistance wire wound around a receptacle for the material.
The induction type consists of a coil wound about a ferrite core which is jllYt~posed with respect to the vessel containing the ink.
25 Allt7ll, .I~,'y the coil may be wound about the vessel wherein the said vessel acts as the core, directly heating the ink.
The ejection point may also be heated to maintain the required viscosity of the ink.
Such heating of the ejection point may be constant or pulsed. The heating of the ejection point may be a point source heater such as an infrared laser diode.
35 In the case of a powdered ink a powder feeder may be used to supply powder to the heahng stage where it is melted in either one or two stages to a required viscosity for ejection.
AMEN~ED SHEEr __ , PCI~/AU 9 4 / O O 0 6 ~
RECEIVED 2 3 DEC t994 In the case of a highly viscous ink this rnay be supplied in a cartridge 215 5 9 4 2 with a spring loaded piston at one end. The spring pressure is adapted to push the paste-like or treacle-like ink directly to the heating chamber.
The ink may be composed of a low melting point wax or resin combined with a pigment phase. Examples of these materials include AC6, a polyethylene wax made by Allied Sinal; Elvax 210, an ethylene vinyl acetate resin made by Du Pont:; Syntha Wax, a hydluy~ d 10 castor oil made by Lever and Kitchen; Paraffin wax, made by Exxon and mixtures thereof. The pigment may be selected from any of a range of pigments dependi"g upon the colour required. Examples of pigments include organic pigments such as Irgalite Blue LGLD, a Pigment Blue 15:3 made by Ciba Geigy: Microlith Black CT, a Pigment 15 Black 7 made by Ciba-Geigy: Monolite Yellow GNA, a Pigment Yellow 1 made by ICI or inorganic pigments such as silicas, metallics or magnetic iron oxides.
Viscosity of inks may be optimised or pre-disposed for droplet 20 fommation. This may be achieved by controlling the temperature of the heating points or , - ~ 'Iy at the ejection point. Viscosity of the ink may be changed by the addition of a viscosity control agent such as Energol WM2, a paraffin oil made by BP Chemicals, or the like.
25 In one form the ejection point may be provided by a needle point having a radius of curvature of from 5 to 50 microns or the ejection point may be provided by an elongate edge having a semi-cylindrical surface having a radius of curvature of 5 to 50 microns. A' " ~loly the ejection point may comprise a matrix of ejection points.
The apparatus according to this invention may be adapted to provide droplets on demand or to provide a continuous stream of droplets which can be deflected by ele~it,~ means external to the ~Jptll 1~ The supply of droplets on demand may be provided by 35 providing a pulséd electrical potential or pulsed heating to the ejection point.
This peliodi~:ly applied potential may be of any waveform which allows consistent ejection of droplets from the ejection point. Preferred AMENDED SHEEr PC~iAU g 4 / O ~ 0 6 -RECEIVED 2 3 OEC l99i ~vc.v~""s include square waves and puises which may have an 21~ 5 g ~ 2 offset or threshold potential.
The electrical potential applied to the ejection point may be in the range of +500 to +5000 volts. A" " ' v~ly the electrical potential applied to the ejection point may comprise a constant bhreshold in the range of +500 to +5000 volts and a pulsed voltage of up to + 800 volts.
Pulsed heating may be provided by a solid state infrared laser diode to provide a point source of heating at the ejection point.
Such a heating device may exhibit specific properties such as fast switching time, ap~ ' heat output with respect to wavelength, bandwidth and heating power for melting the material such as the material, and suitable spot size wibh respect to the ~i",~,~sio,~s of the ejection point.
Generally it can be seen that this invention provides droplet formation at an ejection point and the el~u1,~ ejecbon of such droplets.
Although the ",e~;l Idl lialll for operation of the droplet formation is not fully u"de,:,~uod one theory, to which bhe applicants are not ,1ecessd,ily bound, is as follows: Particles in the reduced viscosity material flowing to the ejection point are inherently charged or charged to the same polarity as the ejection point. More and more particles continue to build up on the ejection point within a forming droplet of the carrier liquid of the material and with increasing repulsion the particles tend to move away from bhe ejection point until ele.;b~ ' ' repulsion between bhe ejection point and the forming droplet of the charged particles builds up to such an extent that surface tension of the entrained carrier liquid can no longer hold the droplet to the ejecbon point. At this stage bhe droplet is repulsed by ele.,l,~ " means.
It may be particularly noted that because the repulsion is subaldl~ l'y ele~;t,~ no earthed substrate is necessary to attract bhe droplets to a substrate and in fact cu"~ ,dble distances of droplet flight can occur before they impinge a substrate. This enables suitable ~le~lualdliu or obher forms of deflection equipment to provide whatever patterning of droplets is required on a substrate.
AMENDED SHEEr IPEA/AU
P~/AU y 4 / ~ O 0 6 _ RECEIVEO 2 3 DEC f994 9 21~94~
The a~ r,l may include a pair of ejection points each producing droplets of one cu, l l~Jo"~l ll of a two col l l~.vl~ adhesive system This would provide an adhesive ~ gun.
This then generally describes the invention but to assist in ulld~ illg the invention reference will now be made to the accvllllJallying drawings which show a preferred ~Illbv~illlelll of the invention and illustrates a II,eo,~.:;c,al action of the invention.
g~lFF ~ESCRIPTION OFDRAWINGS
In the drawings:
15 FIG. 1 shows a sectional view of droplet formation apparatus of an L,Odil l lel 11 of the invention;
FIG. 2 shows a sectional view of an -' -ll ic elllbodil"~ of a droplet formation ~rp~r~tl Ic and FIG. 3 shows a sectional view of a further " I ,1~ ~ll ,I,o.li"~"l of adroplet formation apparatus.
DESCRIPTION OF THE PRE~R~I ) E~ ~nO~ 'T
FIG. 1 illustrates the one ~IllI,cldi~ lll of the invention for use in forming droplets of an ink.
The apparatus for 9~"t:~.'k~" of discrete droplets from a solid ink 30 consists of a body 1 which may be of an insulaUng material fashioned to a tapered point. Extending from the body is a hollow tube 2 of an electrical and thermal conducting material which is ~le~ llJ charged by electrical conductor 3 extending from a power source 4. The ejecUon point 6 is formed at a tip of the tube 2 and is of a selected 35 radius of curvature, in this case a spherical point. The body has an aperture 7 extending through it to the tube 2. The aperture 7 is comprised of a first portion 8 of a first diameter, adapted to receive a stick 9 of a solid ink. A heating coil 10 around the first portion 8 provides heating to soften the stick of ink g to such an extent that AMENDED 8HEEr IPEA~AU
PCI~/AU y 4 / O ~ 0 6 RECEIVE~ 2 3 DEC ~994 spring 11 can e%tnude the ink through a tapered portion 12 of the 21 ~ ~ 9 ~ 2 aperture 7 into a second portion 13 of reduced diameter. In this second portion 13 a further heating coil 14 provides heating to further melt the ink until it is at a viscosity to enable flow to the ejection point 5 under the pressure supplied by spring 11 and droplet formation. At the ejection point the ~ o~ldli~ charge causes droplet formation as discussed earlier.
FIG. 2 illustrates another ~",bo~i",~r,~ of the apparatus for gelleldliun 10 of discrete droplets from a solid ink. Those parts which are the same as in FIG. 1 have the same reference numerals.
A body 1 which may be of an insulating material is fashioned to a tapered point. Extending from the body is a tube 2 of a thermally and 15 el~-,t, 'Iy conducting material which is eleut,i~.:ly charged by electrical conductor 3 e%tending from a power source 4. The ejection point 6 is at the tip of the tube 2 and tapers to a point of a selected radius of curvature, in this case a spherical point. The body has a hollow aperture 7 e%tending through it to the tube 2 and the ejection 20 point 6. The aperture 7 is adapted to receive a stick g of a solid ink. A
heating coil 10 around the aperture 7 softens and expands the ink 9 extruding said ink through aperture 7 into the tube 2 such that ink of the correct viscosity to allow droplet formation flows to the ejection point 6 under pressure. At the ejection point the ele~:,ldli~ charge 25 causes droplet formation as discussed earlier. A plug 15 closes off the end of the aperture 7 remote from the tube 2 to enable pressure formed by expansion of the meltable ink on melting to direct ink to the ejection point 6.
3û FIG. 3 illustrates yet another ~",bodi",~"l of the apparatus for ytsllel dliol1 of discrete droplets from a solid ink. Those parts which are the same as in FIG. 1 have the same reference numerals.
A body 1 which may be of an insulating material fashioned to a 35 tapered point. Extending from the body is a hollow tube 2 of a thermally and ~lecl,ki.~lly conducting material which is eleul,i~
charged by electrical conductor 3 extending from a power source 4.
The ejection point 6 is formed at a tip of the tube 2 which tapers to a point on one edge of the tube of a selected radius of curvature, in this AMENDED SHEET
IP~AU
, . ---- _ . . ..
~CI/AU y 4 ¦ U U U
RECEIVE~ 2 3 DEC 199 11 21 ~9~2 case a spherical point. The body has an aperture 7 extending through it to the tube 2. The aperture 7 is c~, I IlJ, i~ed of first portion 8 of a first diameter adapted to receive a stick 9 of a solid ink. A heating coil 10 around the first portion 8 provides heating to soften the stick of ink 9 to such an extent that spring 11 can extrude the ink through the tapered portion 12 of the aperture 7 into a second portion 13 of reduced diameter and into the tube 2. Further heating is provided by an infrared solid state laser diode 16 and an optical fibre 17 directed to the tube 2. This provides heat which further melts the ink until it is at a viscosity to flow to the ejection point and to enable formation of droplets. At the ejection point the eleutl. charge causes droplet formation, as discussed earlier, when the viscosity has been reduced by the heat from the infrared solid state laser diode 16 via the optical fibre 17. This heating may be pulsed to enable selected or pulsed formation and ejection of droplets.
Examples of operation of droplet formation according to this invention are given in the following examples 1 to 6.
In these examples an ink was provided by blending 999 of Syntha Wax (a h~ilugt:ll castor oil) and 19 of Pigment Blue 15 which were placed into a heated attritor milling device and heated to 1 50C to affect the melting of the Il ,~", lO,UId::~ti;: materials. After milling for 6 hours, the molten ink was removed from the attritor and allowed to solidify by cooling.
Viscosity of this ink at an op~- Idl temperature to allow droplet formation was 10 mPa.s.
EY~mple 1 This ink was placed in the apparatus as described with reference to the ~",L,o~ii",e";~ shown in FIG 1. with bond paper placed 20mm from the single point ejection point with a radius of curvature of 25 microns.
Excellent results were obtained when the ejection point was at 135 C
and + 600 volt pulses were applied at 5000 Hz on top of the threshold potential of +1500 volts. Printed drop size was 10 microns with excellent colour density and integrity.
ANiENDED SHEET
PCI/AU ~ 4 / U O 0 6 RECEt~ED 2 3 DEC 19 12 21 5~9 42 Example 2 This ink was placed in the apparatus as described in FIG 1. with bond paper placed 20mm from the single point ejection point with a radius of curvature of 25 microns. Excellent results were obtained when the 5 ejection point was at 135 C and +800 volt pulses were applied at 5000 Hz on top of the threshold potential of +2000 volts. Printed drop size was 20 microns with excellent colour density and integrity.
Fx~mple 3 10 This ink was placed in the apparatus as described in FIG 1. with bond paper placed 1 Omm from the single point ejection point with a radius of curvature of 25 microns. Excellent results were obtained when the ejection point was at 135 C and +600 volt pulses were applied at 5000 Hz on top of the threshold potential of +1500 volts. Printed drop size 15 was 70 microns with excellent colour density and integrity.
EYArnple 4 This ink was placed in the apparatus as described in FIG 1. with bond paper placed 1 Omm from the single point ejection point with a radius of 20 curvature of 25 microns. Excellent results were obtained when the ejection point was at 135 C and +800 volt pulses were applied at 5000 Hz on top of the threshold potential of +2000 volts. Printed drop size was 150 microns with excellent colour density and integrity.
25 FY~Ie 5 This ink was placed in the apparatus as described in FIG 1. with bond paper placed 5mm from the single point ejection point with a radius of curvatu~e of 25 microns. Excellent results were obtained when the ejection point was at 135 C and +600 volt pulses were applied at 5000 30 Hz on top of the threshold potential of +1500 volts. Printed drop size was 150 microns with excellent colour density and integrity.
AMENDED SHEEr IPEVAU
PCrIAU 9 4 / O O 0 6 -RECEIVED 2 3 DEC 19n' 13 21 559~2 FY~rr~ple 6 This ink was placed in the apparatus as described in FIG 1. with bond paper placed 5mm from the single point ejection point with a radius of curvature of 25 microns. Excellent results were obtained when the ejecbon point was at 135 C and +800 volt pulses were applied at 5000 Hz on top of the threshold potential of +2000 volts. Printed drop size was 300 microns with excellent colour density and integrity.
The Examples 7 to 13 illustrate droplet formation according to the method and apparatus of this invention with other inks. These inks were manufactured by the method as disclosed in previous examples.
All viscosity measurements in these examples were performed on a Haake IlI,eu", '~.. Rheostress RS100.
15 FY~rnlple 7 Paramn Wax 439 Irgalite Blue LGLD 49 20 Viscosity of this ink at ùpt~ k~lldl L~"l,ue, ~re was 45 mPa.s The ink was placed in the apparatus as described with reference to the ~,nl,o~i",t r,l shown in FIG 1. with bûnd paper placed 10mm from a single point ejection point with a radius of curvature of 25 microns.
25 Excellent results were obtained when the ejection point was at 135 C
and +800 volt pulses were applied at 5000 Hz on top of the threshold potential of +2000 volts. The printed drop had excellent colour density and integrity.
30FY~rnvle 8 Paramn Wax 809 Elvax 210 99 Irgalite Blue LGLD 49 35 Viscosity of this ink at o~, )ndl temperature was 32 mPa.s The ink was placed in the apparatus as described with reference to the ~:"lbo~i",~"l shown in FIG 1. with bond paper placed 1 0mm from the single point ejection point with a radius of curvature of 25 microns.
AMENDED SHEET
, IPE4/AU
RECE18ED 2~ ~EQC ~5 Excellent results were obtained when the ejection point was at 135 C 21~ ~ 9 4 2 and +800 volt pulses were applied at 5000 Hz on top of the threshold potential of +2000 volts. The printed drop had excellent colour density and integrity.
FY~rnple 9 Paraffin Wax 809 Elvax 210 99 Energol WM2 209 10Irgalite Blue LGLD 49 Viscosity of this ink at ~.el Idl ~ Ires was 15 mPa.s.
The ink was placed in the apparatus as described with reference to the 15 e",L,odi",~"l shown in FIG. 1 with bond paper placed 1Omm from the single point ejection point with a radius of curvature of 25 microns.
Excellent results were obtained when the ejection point was at 135C
and +800 volt pulses were applied at 5000 Hz on top of the threshold potential of +2000 volts. The printed drop had excellent colour density 20and integrity.
EY~rnple 10 Paraffin Wax 499 AC6 49g 25Irgalite Blue LGLD 19 Viscosity of this ink at CJ~61 " lal temperature was 31 mPa.s.
The ink was placed in the apparatus as described with reference to the 30 ~Illbo~ l shown in FIG. 1 with bond paper placed 10mm from the single point ejection point with a radius of curvature of 25 microns.
Excellent results were obtained when the ejection point was at 135 C
and +800 volt pulses were applied at 5000 Hz on top of the threshold potential of +2000 volts. The printed drop had excellent colour density.
AMENDED SHEEr IPEA/AU
PC~/AU 9 4 / O O ~ 6 RECElVEa 2 3 DEC ~9 Example 11 15 21$S9~2 Paraffin Wax 99g Microlith Black CT 19 5 Viscositv of this ink at ~, dIiu11dl temperature was 2.5 mPa.s.
The ink was placed in the apparatus as described with reference to the ~" ,IJ~d;, I ,er,L shown in FIG. 1 with bond paper placed 1 Omm from the single point ejection point with a radius of curvature of 25 microns.
10 The ejection point was at 1 35C and +800 volt pulses were applied at 5000 Hz on top of the threshold potential of +2000 volts. The printed drop had poor colour densitv and integrit~v.
EY~ le 12 15 Pardffln Wax 999 Monolite Yellow GNA 19 Viscosit~v of this ink at u~uel ,al temperature was 13 mPa.s.
20 The ink was placed in the apparatus as described with reference to the ~"lbodi",t:"l shown in FIG. 1 with bond paper placed 10mm from the single point ejection point with a radius of curvature of 25 microns.
The ejection point was at 135C and +800 volt pulses were applied at 5000 Hz on top of the threshold potential of +2000 volts. The printed 25 drop had poor colour densitv and integritv.
FY~rn~le 13 Paraffin Wax 439 Irgalite Blue LGLD 19 Viscositv of this ink at o~.e, _ ~dl temperature was 45 mPa.s.
The ink was placed in the apparatus as described with reference to the 35 ~"l~o,li",~"l shown in FIG. 3 with bond paper placed 10mm from the single point ejection point with a radius of curvature of 25 microns.
Excellent results were obtained when the ejection point was at 135C
and the laser was modulated at 5000 Hz. A potential of +2800 volts AMENDED SHEEr IPE 4tAU
Pcr/AV ~4 / ~nn 6 .
RECEI V ED 2 3 ~C -~9~
was applied to the ejection point. The printed drop had an excellent 21 ~ S 9 ~ 2 colour density and integrity.
It will be seen that by this invention there is provided a simple method 5 and apparatus by which droplets of a meltable solid, powdered or highly viscous material such as an ink may be produced.
AMENDED SHEET
Claims (35)
1. An apparatus for generation of droplets of a material from a meltable powdered, solid or highly viscous material comprising means to reduce the viscosity of the powdered, solid or highly viscous material to a viscosity which will enable droplet formation, means to supply the reduced viscosity material to an ejection point, and means to apply an electrical potential to the ejection point to form an electric field at the ejection point whereby to enable formation and ejection of droplets of the material from the ejection point.
2. An apparatus for generation of droplets of a material from a meltable powdered, solid or highly viscous material comprising a particulate solid and a meltable carrier, the apparatus comprising viscosity reduction means to reduce the viscosity of the material to a viscosity which will enable droplet formation, means to supply the reduced viscosity material to an ejection point, and means to apply an electrical potential to the ejection point to form an electrostatic field at the ejection point whereby to enable formation and ejection of droplets of the material from the ejection point by electrostatic repulsion.
3. An apparatus as in Claim 2 wherein the means to reduce the viscosity of the powdered, solid or highly viscous material reduces the viscosity by heating or by pressure.
4. An apparatus as in Claim 2 wherein the means to supply the reduced viscosity material to an ejection point comprises a spring loaded chamber adapted to contain pellets or a stick of the material and wherein the means to reduce the viscosity includes resistance or induction heating means to melt the pellets or stick of the material to the required viscosity.
5. An apparatus as in Claim 4 wherein the means to reduce the viscosity includes a two stage heating means with the first stage adapted to soften the material to such a viscosity that it can be forced to a second stage heater which is adapted to reduce the viscosity of the material to the final required viscosity.
6. An apparatus as in Claim 2 wherein the ejection point includes heating means to maintain the viscosity of the material at a viscosity which will enable droplet formation.
7. An apparatus as in Claim 6 wherein the heating means at the ejection point comprises a solid state infra red laser diode.
8. An apparatus as in Claim 7 wherein the solid state infra red laser diode is adapted to be pulsed to provide intermittent heating of the ejection point.
9. An apparatus as in Claim 2 wherein the ejection point is selected from a needle point having a radius of curvature of from 5 to 50 microns, an elongate edge having a semi cylindrical surface having a radius of curvature of 5 to 50 microns or a matrix of ejection points.
10. An apparatus as in Claim 2 wherein the electrical potential applied to the ejection point is in the range of +500 to +5000 volts.
11. An apparatus as in Claim 2 wherein the means to apply an electrical potential to the ejection includes means to pulse the electrical potential so that there is periodic formation and ejection of droplets from the ejection point.
12. An apparatus as in Claim 2 wherein the electrical potential applied to the ejection point comprises a constant threshold in the range of +500 to +5000 volts and a pulsed voltage of up to + 800 volts.
13. An apparatus as in Claim 2 wherein the pulsed voltage comprises a square waveform.
14. An apparatus for the generation of droplets of an ink from a solid meltable ink, the ink being of a type including a pigment and a meltable carrier, the apparatus comprising a body having a chamber therein to receive the solid ink, heating means to melt the ink within the chamber, a capillary tube extending from the chamber to an ejection point to supply melted ink to the ejection point and means to apply an electrical potential to the ejection point to form an electrostatic field at the ejection point whereby to enable formation and ejection of droplets of the ink from the ejection point by electrostatic repulsion.
15. An apparatus for the generation of droplets of an ink from a solid meltable ink as in Claim 11 further including means to pulse the electrical potential to thereby enable periodic formation and ejection of droplets from the ejection point.
16. An apparatus for the generation of droplets of an ink from a solid meltable ink as in Claim 11 further including means to provide intermittent heating of the ejection point to reduce the viscosity of the ink at the ejection point to thereby enable periodic formation and ejection of droplets from the ejection point.
17. An apparatus for the generation of droplets of an ink from a solid meltable ink as in Claim 13 wherein the means to provide intermittent heating of the ejection point to reduce the viscosity of the ink at the ejection point is a solid state infra red laser diode.
18. An apparatus for generation of droplets of a material from a meltable powdered, solid or highly viscous material comprising a particulate solid comprised of chargeable particles and a meltable carrier, the apparatus comprising viscosity reduction means to reduce the viscosity of the powdered, solid or highly viscous material to a viscosity which will enable droplet formation, means to supply the reduced viscosity material to an ejection point, and means to apply an electrical potential to the ejection point to form an electrostatic field at the ejection point whereby to enable formation and ejection of droplets of the material from the ejection point by electrostatic repulsion.
19. An apparatus for generation of droplets of an ink from a meltable powdered, solid or highly viscous ink comprising a particulate pigment of chargeable particles and a meltable carrier, the apparatus comprising viscosity reduction means to reduce the viscosity of the powdered, solid or highly viscous ink to a viscosity which will enable supply of the reduced viscosity ink to an ejection point, means to supply the reduced viscosity material to the ejection point, means to apply an electrical potential to the ejection point to form an electrostatic field at the ejection point and means to provide point source heating of the ejection point to reduce the viscosity of the ink to a viscosity which will enable droplet formation whereby to enable formation and ejection of droplets of the material from the ejection point by electrostatic repulsion.
20. A method of formation of droplets from a meltable powdered, solid or highly viscous material comprising the steps of reducing the viscosity of the material to a viscosity which enable droplet formation, providing the reduced viscosity material to an ejection point, applying an electrical potential to the ejection point to form an electric field at the point and thereby causing the reduced viscosity material to form droplets on the ejection point and ejecting such droplets away from the ejection point by electrostatic repulsion.
21. A method as in Claim 20 wherein the viscosity is reduced by heating or by pressure.
22. A method as in Claim 20 wherein the electrical potential forming the electric field is constant and the droplet formation is dependant upon the degree of reduction of viscosity.
23. A method as in Claim 20 wherein the heating to provide reduction in viscosity is pulsed so that there is periodic formation and ejection of droplets from the ejection point.
24. A method as in Claim 20 wherein the reduction of viscosity is constant and the droplet formation is dependant upon the variation of the electrical potential forming the electric field.
25. A method as in Claim 24 wherein the electrical potential forming the field is pulsed so that there is periodic formation and ejection of droplets from the ejection point.
26. A method as in Claim 20 wherein the ejection point is provided by a needle having a radius of curvature at its tip in the range of 5-50 microns.
27. A method as in Claim 20 wherein the ejection point is provided by an elongate sharpened edge providing a number of ejection points along the elongate edge or by a matrix of ejection points.
28. A method as in Claim 20 wherein the solid or highly viscous material is an ink comprised of a carrier and a pigment and the carrier is a non-electrically conducting when in the reduced viscosity state and the pigment is comprised of chargeable particles.
29. A method as in Claim 28 wherein the chargeable particles are chargeable to the same polarity as the electrical potential applied to the ejection point.
30. A method as in Claim 28 wherein the ink is comprised of a low melting point wax or resin combined with a pigment and the wax or resin is selected from a low molecular weight polyethylene, hydrogenated castor oil, ester wax, paraffin wax, rosins, and ethylene vinyl acetate copolymers and mixtures thereof and the pigment is selected from organic pigments such as Pigment Blue 15, Pigment Yellow 1 and Pigment Black 7 or inorganic pigments such as silicas, metallics or magnetic iron oxides.
31. A method as in Claim 20 wherein the electrical potential applied to the ejection point is in the range of +500 to +5000 volts.
32. A method as in Claim 20 wherein the electrical potential applied to the ejection point comprises a constant threshold in the range of +500 to +5000 volts and a pulsed voltage of up to + 800 volts.
33. An apparatus as in Claim 20 wherein the pulsed voltage comprises a square waveform.
34. A method of formation of droplets of ink for printing purposes from a meltable powdered, solid or highly viscous ink, the ink comprising a pigment comprising chargeable particles and a non-conducting carrier, the method comprising the steps of reducing the viscosity of the ink by heating means to a viscosity which enable droplet formation, flowing the reduced viscosity ink to an ejection point, applying an electrical potential to the ejection point to form an electrostatic field at the point and thereby causing the reduced viscosity material to form droplets on the ejection point and ejecting such droplets away from the ejection point by electrostatic means.
35. A method of formation of droplets of ink for printing purposes from a meltable powdered, solid or highly viscous ink, the ink comprising a pigment comprising chargeable particles and a non-conducting meltable carrier, the method comprising the steps of reducing the viscosity of the ink by heating means to a viscosity which will enable flow of the melted ink to an ejection point, flowing the reduced viscosity ink to the ejection point, applying an electrical potential to the ejection point to form an electrostatic field at the point, providing point source heating at the ejection point to reduce the viscosity of the ink to a viscosity which will enable droplet formation and thereby causing the reduced viscosity material to form droplets on the ejection point and ejecting such droplets away from the ejection point by electrostatic means.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| AUPL7274 | 1993-02-12 | ||
| AUPL727493 | 1993-02-12 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA2155942A1 true CA2155942A1 (en) | 1994-08-18 |
Family
ID=3776707
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA002155942A Abandoned CA2155942A1 (en) | 1993-02-12 | 1994-02-11 | Method and apparatus for the production of droplets |
Country Status (8)
| Country | Link |
|---|---|
| EP (1) | EP0683731B1 (en) |
| JP (1) | JPH08506536A (en) |
| CN (1) | CN1045745C (en) |
| AT (1) | ATE196447T1 (en) |
| CA (1) | CA2155942A1 (en) |
| DE (1) | DE69425958T2 (en) |
| RU (1) | RU2110409C1 (en) |
| WO (1) | WO1994018011A1 (en) |
Families Citing this family (20)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5800600A (en) * | 1994-07-14 | 1998-09-01 | Tonejet Corporation Pty Ltd | Solid ink jet ink |
| AU682975B2 (en) * | 1994-07-14 | 1997-10-23 | Tonejet Limited | Solid ink jet ink |
| US5510821B1 (en) * | 1994-09-20 | 2000-05-02 | Tektronix Inc | Solid ink stick |
| US5647543A (en) * | 1995-01-31 | 1997-07-15 | Graco Inc | Electrostatic ionizing system |
| EP0734777A3 (en) * | 1995-03-28 | 1997-08-20 | Graco Inc | Electrostatic ionizing system |
| GB9601212D0 (en) | 1996-01-22 | 1996-03-20 | The Technology Partnership Plc | Inkjet printer nozzle plate |
| JP3185729B2 (en) * | 1997-11-07 | 2001-07-11 | 富士ゼロックス株式会社 | Image forming apparatus and image forming method |
| US6136442A (en) * | 1998-09-30 | 2000-10-24 | Xerox Corporation | Multi-layer organic overcoat for particulate transport electrode grid |
| US6328409B1 (en) | 1998-09-30 | 2001-12-11 | Xerox Corporation | Ballistic aerosol making apparatus for marking with a liquid material |
| US6116718A (en) * | 1998-09-30 | 2000-09-12 | Xerox Corporation | Print head for use in a ballistic aerosol marking apparatus |
| DE19921925A1 (en) * | 1999-05-12 | 2000-11-16 | Dmc2 Degussa Metals Catalysts | Process for decorating solid materials |
| US6579574B2 (en) * | 2001-04-24 | 2003-06-17 | 3M Innovative Properties Company | Variable electrostatic spray coating apparatus and method |
| JP2004299097A (en) * | 2003-03-28 | 2004-10-28 | Seiko Epson Corp | Liquid drop ejector, electro-optical device, electronic apparatus, process for manufacturing electro-optical device, and ejection control method for liquid drop ejector |
| DE10353112B4 (en) * | 2003-11-12 | 2006-12-28 | Metec Ingenieur-Ag | Printhead and its use |
| CN101321899B (en) | 2005-10-31 | 2011-08-10 | 普林斯顿大学理事会 | Electrohydrodynamic printing and manufacturing |
| CN108254950B (en) * | 2018-02-09 | 2021-01-08 | 京东方科技集团股份有限公司 | Quantum dot pellet spraying equipment |
| KR102210311B1 (en) * | 2018-11-30 | 2021-02-01 | 서강대학교산학협력단 | Method of producing magnetic iron oxide nanoparticles |
| CN111319358A (en) * | 2018-12-13 | 2020-06-23 | 株式会社Enjet | Electrohydrodynamic printing apparatus |
| WO2020120773A1 (en) * | 2018-12-14 | 2020-06-18 | Poly Pico Technologies Limited | A droplet dispenser for high viscosity liquids |
| CN112431930A (en) * | 2020-11-23 | 2021-03-02 | 石家庄禾柏生物技术股份有限公司 | Sealing valve and liquid outlet structure comprising same |
Family Cites Families (12)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| BE755392A (en) * | 1969-08-28 | 1971-02-01 | Teletype Corp | INK AND ELECTROSTATIC PRINTING APPARATUS |
| IT1116334B (en) * | 1977-12-28 | 1986-02-10 | Olivetti & Co Spa | IMPACT-FREE WRITING DEVICE WITH SELECTIVE EMISSION OF SOLID INK PARTICLES |
| JPS597052A (en) * | 1982-06-30 | 1984-01-14 | インタ−ナショナル ビジネス マシ−ンズ コ−ポレ−ション | Liquid injection recorder |
| CH649040A5 (en) * | 1982-10-08 | 1985-04-30 | Battelle Memorial Institute | DEVICE FOR PROJECTING DROPLETS OF AN ELECTRICALLY CONDUCTIVE LIQUID. |
| US4490731A (en) * | 1982-11-22 | 1984-12-25 | Hewlett-Packard Company | Ink dispenser with "frozen" solid ink |
| US4593292A (en) * | 1984-10-15 | 1986-06-03 | Exxon Research And Engineering Co. | Ink jet apparatus and method of operating ink jet apparatus employing phase change ink melted as needed |
| US4682185A (en) * | 1984-11-08 | 1987-07-21 | Martner John G | Ink jet method and apparatus utilizing a web of hot melt ink |
| EP0213240B1 (en) * | 1985-08-06 | 1990-05-30 | Dataproducts Corporation | Utilizing a phase change ink in ink jetting |
| US4717926A (en) * | 1985-11-09 | 1988-01-05 | Minolta Camera Kabushiki Kaisha | Electric field curtain force printer |
| JP2638879B2 (en) * | 1988-02-09 | 1997-08-06 | ミノルタ株式会社 | Inkjet printer |
| JPH03184855A (en) * | 1989-12-14 | 1991-08-12 | Ricoh Co Ltd | Non-contact type recording device |
| DE69230111T2 (en) * | 1991-12-18 | 2000-01-20 | Tonejet Corp Pty Ltd | METHOD AND DEVICE FOR PRODUCING DISCRETE AGGLOMERATES FROM A PARTICULATE MATERIAL |
-
1994
- 1994-02-11 CA CA002155942A patent/CA2155942A1/en not_active Abandoned
- 1994-02-11 DE DE69425958T patent/DE69425958T2/en not_active Expired - Lifetime
- 1994-02-11 AT AT94907456T patent/ATE196447T1/en not_active IP Right Cessation
- 1994-02-11 CN CN94191362A patent/CN1045745C/en not_active Expired - Fee Related
- 1994-02-11 JP JP6517456A patent/JPH08506536A/en active Pending
- 1994-02-11 RU RU95121653A patent/RU2110409C1/en not_active IP Right Cessation
- 1994-02-11 EP EP94907456A patent/EP0683731B1/en not_active Expired - Lifetime
- 1994-02-11 WO PCT/AU1994/000065 patent/WO1994018011A1/en active IP Right Grant
Also Published As
| Publication number | Publication date |
|---|---|
| JPH08506536A (en) | 1996-07-16 |
| EP0683731A1 (en) | 1995-11-29 |
| DE69425958T2 (en) | 2001-01-25 |
| EP0683731A4 (en) | 1996-04-03 |
| ATE196447T1 (en) | 2000-10-15 |
| DE69425958D1 (en) | 2000-10-26 |
| EP0683731B1 (en) | 2000-09-20 |
| RU2110409C1 (en) | 1998-05-10 |
| WO1994018011A1 (en) | 1994-08-18 |
| CN1045745C (en) | 1999-10-20 |
| CN1119843A (en) | 1996-04-03 |
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