CN1233561A

CN1233561A - Liquid ejecting method and liquid ejecting head

Info

Publication number: CN1233561A
Application number: CN99101791A
Authority: CN
Inventors: 立原昌义; 田村泰之; 村上修一
Original assignee: Canon Inc
Current assignee: Canon Inc
Priority date: 1998-02-10
Filing date: 1999-02-10
Publication date: 1999-11-03
Anticipated expiration: 2019-02-10
Also published as: CA2261375C; JPH11291500A; CN1120087C; KR100320689B1; EP0936070A3; CN1269643C; AU1637799A; EP0936070A2; CA2261375A1; KR19990072572A; CN1493457A

Abstract

A liquid ejecting method using a liquid ejecting head having electrothermal transducer elements for generating thermal energy sufficient to create bubbles in liquid and ejection outlets disposed opposed to the electrothermal transducer elements which are arranged at a density not less than 300 per 25.4mm in a line, the liquid ejection head also having liquid flow paths in fluid communication with the ejection outlets, respectively, wherein the bubble generated by the thermal energy generated by the electrothermal transducer element is brought into communication with ambience while an internal pressure of the bubble is less than an ambient pressure, and wherein droplets having volumes not more than 15x10<-15>m<3> are ejected at a frequency not less than 7kHz.

Description

Liquid jet method and fluid jetting head

The present invention relates to be used for spray liquid jet method and fluid jetting head such as drops such as inks to recording mediums such as paper such as the usefulness of record.Especially, the present invention relates to be used for spraying with extra high frequency the liquid jet method of especially little drop, and also relate to fluid jetting head, the fluid path that promptly comprises a plurality of high-density arrangements is to realize high-resolution record head.

So-called bubble jet type liquid jet method is arranged in various liquid jet methods.According to these methods, in liquid, generate bubble fast, and be used for from the fluid injector liquid droplets by the pressure that bubble produced that generates.It is high that these method liquid spray response, thereby be suitable for very much high-speed record and high density recording.

In spray alveolitoid liquid jet method liquid jet method allow on hot production part the bubble that produces to open the air of nozzle edge.With regard to this class method, known have Japan to postpone publication application No10940/1992,10941/1992,10742/1992 etc.

These methods have following characteristic.At first, they can increase liquid jeting speed, and thereby can improve reliability.The second, they can spray the whole basically liquid that occurs between hot production part and the nozzle, thereby can make the amount of liquid of each injection even.

Because the progress of recording technique has now needed the very high-quality image of record, promptly on recording medium, deposit minimum volume (for example 1.5 * 10 with very high density (for example 600 points/25.4mm or higher) ^-10m ³) drop.In order to write down this high-precision image, nozzle must be with high-density arrangement with the fluid path that leads to nozzle.For example, in order to realize the packing density of above-mentioned 600 points/25.4mm, nozzle must become two parallel row with the density proper alignment of 300 points/25.4mm, on the direction of being expert in the unit in the delegation to another row displacement half pitch.

Use thinner drop recording picture to increase the number of drops that will spray, this has reduced writing speed conversely again.In order to prevent the reduction of this writing speed, must increase the frequency (following product " injection frequency ") that drop sprays from each nozzle per time unit.For example, under the situation of said structure, injection frequency must be at least 7KHz.

And, for the drop by above-mentioned like that little volume writes down high-quality image, must improve the reliability that drop sprays.

As mentioned above, the bubble jet type liquid jet method that allows bubble to link to each other with air is arranged.For example, for example Japan's delay publication application No.16365/1993 has revealed the technology about the state of drop when spraying, and the condition that allows bubble to be connected with air.

When the bubble jet type liquid jet method that allows bubble to be connected with air is used to spray volume is 1.5 * 10 ^-10m ³The ink gun of very little drop the time, confirm that in record operating period drop suddenly can not can be normally injected from the nozzle of its injection from some original drop.This phenomenon is different from the injection failure that occurs in before the fluid jetting head.That is, recording liquid is in time that ink-jet is connected with air and recharge between time of end stopped nozzles suddenly.Thereby before the recovery mechanism of the master unit that uses image device carried out recovery operation, recording liquid can not be ejected from the nozzle that gets clogged.

Fig. 5 is the cross section of having described the fluid injector of above-mentioned phenomenon and having led to the fluid path of nozzle.From Fig. 5 obviously as seen, bubble be connected with air and the drop of recording liquid 501 injected after, nozzle is recorded liquid 501 immediately and blocks.After this time point, in black liquid supply passageway, also remain with recording liquid 501.Yet, do not have recording liquid adjacent, because this is just after liquid sprays with electric transducer 1.In other words, have only air 502 adjacent with electric transducer 1.At this state, even electric pulse is applied to electric transducer 1, the drop of record liquid 501 can not be injected, because do not write down liquid near electric transducer 1.Thereby can't dredge nozzle 4.

And, during the present invention's development, when wherein with arranged in high density the shower nozzle glass of the above-mentioned type of a large amount of fluid paths during with high-frequency drive, must be noted that bubble is connected the state of its meniscus afterwards with air, how the state of the meniscus after particularly connecting is different from the state of the meniscus before connecting.Like this, the object of the present invention is to provide a kind of reliable liquid jet method, Here it is can be not suddenly can not atomizing of liquids liquid jet method, promptly can use bubble jet type fluid jetting head to form the liquid jet method of high-speed record, particularly wherein be used for the nozzle of the minimum drop of high frequency jet so-called side ejector type fluid jetting head with arranged in high density, one to a ground directly in the face of hot production part, and wherein allow bubble to be connected with air.

Be used to realize that the main points of the present invention of the above-mentioned target of the present invention are as follows.

Liquid jet method according to the present invention uses a kind of fluid jetting head, this shower nozzle comprises can produce a plurality of electric transducers of heat energy that are used for generating at liquid the q.s of bubble, one to one directly in the face of a plurality of nozzles of electric transducer configuration, and a plurality of fluid path.Nozzle to be being not less than the density proper alignment of 300/25.4mm, and one is connected to fluid path to one.This liquid jet method is characterised in that the bubble that the heat energy that is produced by electric transducer generates sprays one by one with the frequency that is not less than 7kHz and is not more than 15 * 10 ^-15m ³The drop of volume, and it is open to air when their atomizing of liquids, its internal pressure is lower than atmospheric pressure simultaneously, and the height that is the fluid path in the fluid jetting head is not more than 6 μ m, and the distance between nozzle top and the bottom opening is not more than by nozzle center's leap nozzle minimum range half.

Fluid jetting head according to the present invention comprises can produce a plurality of electric transducers that are used for generating at liquid the heat energy of bubble, directly in the face of a plurality of nozzles of electric transducer to a ground configuration, and a plurality of fluid path.Nozzle and fluid path are arranged to be not less than in the density of 300/25.4mm.Drive signal and put on electric transducer with the frequency that is not less than 7kHz.This fluid jetting head is characterised in that bubble produces and sprays volume one by one and is not more than 15 * 10 in fluid path ^-15m ³Drop, when their liquid droplets, open to air, its internal pressure is lower than atmospheric pressure simultaneously, and is that the height of fluid path is not more than 6 μ m, and the distance between nozzle top and the bottom opening is not more than by nozzle center's leap nozzle minimum range half.

And, liquid jet method according to the present invention uses a kind of fluid jetting head, this shower nozzle comprises can produce a plurality of electric transducers that are used for generating at liquid the q.s heat energy of bubble, and one to a plurality of nozzles that directly dispose in the face of electric transducer, and a plurality of fluid path.Nozzle to be being not less than the density proper alignment of 300/25.4mm, and one is connected to fluid path to one.The bubble that the heat energy that is produced by electric transducer generates sprays volume one by one with the frequency that is not less than 7kHz and is not more than 15 * 10 ^-15m ³Drop.This liquid jet method is characterised in that, it comprises a kind of process, wherein bubble after air is opened, be retained in liquid in the nozzle keep with fluid path in being connected of the liquid of withdrawing from nozzle, and comprise a process, wherein be retained in liquid in the nozzle and the liquid in the fluid path and combine, and applying nozzle again.

Use above-mentioned structure, wherein bubble can not be recorded the liquid obstruction to the nozzle in the open side ejector type fluid jetting head of air.So the undesirable white line phenomenon that can not spray suddenly owing to some nozzle during having prevented from reliably to write down makes it possible to reliably with the flying print high quality image.

Consider the explanation to the following preferred embodiment of the present invention in conjunction with the accompanying drawings, these and other objects then of the present invention, characteristics and advantage will become more obvious.

Fig. 1 (a) is the external perspective view of the fluid jetting head that can be suitable for according to liquid jet method of the present invention, and has described the general structure of shower nozzle.Fig. 1 (b) is the cross section at the online A-A of fluid jetting head place among Fig. 1 (a), and has described the general structure of shower nozzle.

Fig. 2 (a) is the major part of the fluid jetting head among Fig. 1, i.e. the vertical cross-section of one of nozzle and one of fluid path.Fig. 2 (b) is the top view of the major part of fluid jetting head shown in Fig. 2 (a).

Fig. 3 (a)-(g) is the cross section according to the major part of liquid jet method of the present invention fluid jetting head applicatory, and has described the operating procedure of shower nozzle.

Fig. 4 is the perspective view of the partly cut-away of liquid injection apparatus one example that adapts with liquid jet method according to the present invention fluid jetting head applicatory, and has described its general structure.

Fig. 5 is the amplification cross section according to fluid jetting head major part of the present invention, and has described by problem solved by the invention.

Fig. 6 is the cross section according to liquid jet recording head of the present invention, and has described the vertical taper of nozzle.

Embodiment 1

Fig. 1 (a) is the external perspective view of the fluid jetting head that can be suitable for according to liquid jet method of the present invention, and has described the general structure of shower nozzle.Fig. 1 (b) is the cross section at the online A-A of fluid jetting head place among Fig. 1 (a), and has described the general structure of shower nozzle.Among Fig. 1, the substrate that label 2 expression is formed by Si has formed heating and nozzle as heater by thin film technique on it.To describe heating and nozzle in detail after a while.Shown in Fig. 1 (a), on this element substrate 2, a plurality of nozzles 4 are arranged in parallel two row, and the half pitch that staggers on the direction that makes nozzle 4 in the delegation be expert to the nozzle 4 in another row seems the footprint of bird.Use binding agent element substrate 2 to be fixed to the part of L shaped support member 102.Be fixed to the connecting line substrate 104 in addition on the support member 102, the connecting line pressure welding on it is connected to the connecting line on the element substrate 2.Consider that machinability support member 104 is formed by aluminium.Label 103 expressions one molding, support member 102 partly inserts wherein so that supported by molding 103.Molding 103 comprises liquid supply passageway 107, provides to the nozzle that is contained on the element substrate from the liquid storage part (not shown) by this path liquid (for example black liquid).And the function of molding 103 is also detachable to the effect of liquid injection apparatus integral installation according to fluid jetting head of the present invention as playing, and removably it is fixed on the liquid injection apparatus.To describe liquid injection apparatus in detail after a while.

Element substrate 2 comprises the connecting path 105 that runs through element substrate 2, and the liquid that provides through the liquid supply passageway 107 of this path by molding 103 offers nozzle.Connecting path 105 is connected to the fluid path that leads to nozzle one by one, and also plays the effect of shared sap cavity.

Fig. 2 (a) is the major part of the fluid jetting head among Fig. 1, i.e. the vertical cross-section of nozzle and fluid path.Fig. 2 (b) is the top view of the major part of fluid jetting head shown in Fig. 2 (a).

As shown in Figure 2, fluid jetting head according to the present invention is equipped with the rectangle heating as heater 1, and these elements are arranged in the precalculated position on the element substrate 2 one by one.On heater 1, be placed with nozzle plate 3.Nozzle plate 3 is provided with the direct one by one rectangular nozzle 4 towards heater 1 core.As among Fig. 2 (b) as seen, the openings of sizes of nozzle 4 is indicated by a label So.The top and bottom " face " of

label

41 and 42 indication nozzles 4.In the present embodiment, top and bottom " face " is the face of the imagination: the face that prolongs the formed imagination of nozzle top and bottom face by the top and bottom opening of crossing over nozzle 4.

Referring to Fig. 2 (a), the institute gap equals the height Tn of fluid path 5 between heater 1 and the nozzle plate 3, and is determined by the height of fluid path wall 6.Referring to Fig. 2 (b), wherein fluid path 5 prolongs in the direction of arrow label X indication, arranges by a plurality of parallel row perpendicular to direction X with 5 one nozzles 4 to a connection of fluid path.Among Fig. 1 (b), a plurality of fluid paths 5 are connected to connecting path 105, and this path also plays the effect in common liquid chamber.The thickness that equals the nozzle passage 3 of the distance between the top and

bottom face

41 and 42 of the nozzle imagination is represented by a label To.

Below will illustrate to use and have the embodiment of the fluid jetting head of said structure according to liquid jet method of the present invention.

Fig. 3 (a)-(g) is the cross section according to the major part of liquid jet method of the present invention fluid jetting head applicatory.They have described the operating procedure of shower nozzle.

Referring to Fig. 3 (a), under normal condition, meniscus 11 is on the top of nozzle.Under this state, driving voltage is applied to heater 1.Wish to use short pulse to drive heater 1, to prevent that just meniscus is withdrawn excessively by excessive air bubble growth.Wish that electric pulse puts on no more than 3.5 microseconds of duration of heater 1 atomizing of liquids.This is owing to following reason.If the pulse duration, then air bubble growth was excessive greater than 3.5 microseconds, the distance that nozzle is left in this position of causing liquid to spray the back meniscus is too far away.As a result, the time that recharges becomes bigger, and this makes fluid jetting head be unsuitable for high-speed record.Can use the multiple-pulse driving method, in other words, every injection applies the driving method of two or more pulses.Under this situation, the duration of pulse, promptly wish to be used for the pulse that main pulse that recording liquid sprays applied before applying and be not more than 1.5 microseconds.Wish that the interval between preamble pulse and the main pulse is not more than 2.0 microseconds.If the duration of preamble pulse surpasses 1.5 microseconds, and/or the interval between preamble pulse and the main pulse surpasses 2.0 microseconds, and then bubble growth becomes too, and this causes the meniscus bigger distance of withdrawing conversely.The withdrawal that meniscus is bigger makes the fluid jetting head can not be with high frequency jet liquid; In other words, this makes purpose of the present invention not realize.

For the suitable driving voltage value of realizing target of the present invention is 1.1 to 1.3 times of threshold voltage vt h that spray to liquid.If driving voltage is not more than 1.1 times of threshold voltage vt h, suppose to have produced bubble and liquid droplets, then liquid jeting speed is low excessively, can cause that injected drop leaves predetermined route.And, spray the instability that becomes at high frequency liquid.Otherwise, if driving voltage is not less than 1.3 times of threshold voltage vt h, then bubble length becomes excessive, can cause the bigger distance of meniscus withdrawal, this has prolonged the time that recharges conversely, and/or too increase the speed that liquid sprays, increased the amount of scattering that when drop bump recording medium, occurs.Like this, above-mentioned drive voltage range is one of desirable condition to the present invention.

Following with reference to Fig. 3 (b), when driving voltage puts on heater 1, cause bubble 301 growths in the liquid that contacts with heater 1.Then, when bubble 301 growths, nozzle 4 on bubble 301 top sides and the liquid in the fluid path 5 upwards expand from 4 tops of nozzle.In this course, begin to be reduced to below the atmospheric pressure greater than the pressure of atmospheric bubble 301.

Following with reference to Fig. 3 (c), when the bubble continued growth, nozzle 4 on bubble 301 top sides and the liquid in the fluid path 5 upwards spray from 4 tops of nozzle.Yet in this stage, bubble 301 also is not connected with air, and because the meniscus in the continued growth fluid path 5 of bubble 301 keeps withdrawal.At the eve that bubble 301 is connected with air, the front end of the recording liquid in the fluid path 5 by means of liquid stream, is still in 42 places, bottom surface of the imagination of nozzle 4, and also is connected with recording liquid on the inner surface that is retained in nozzle 4.Bubble 301 internal pressures keep below atmospheric pressure, up to bubble 301 with till air is connected.Bubble 301 internal pressures are equal to or higher than atmospheric pressure if bubble 301 is connected simultaneously with air, then cause splash when the unstable liquid adjacent with nozzle 4 is connected between bubble 301 and air.And, do not have masterpiece to be used for unsettled liquid is withdrawn into fluid path, thereby can not prevent the unstable liquid splash adjacent with nozzle 4.

Following with reference to Fig. 3 (d), with when air is connected or after just having connected,, and leave the top of nozzle 4 at bubble 301 from nozzle 4 liquid droplets 12.Leave the moment of the top of nozzle 4 at drop, the left-hand side of nozzle 4 in the drawings takes place if drop separates with liquid in the nozzle 4, the record liquid at 42 places, bottom surface that the major part that then is retained in the above-mentioned recording liquid on the nozzle inner surface is retained in the above-mentioned imagination of nozzle spurs downwards, and last and fluid path 5 interior record liquid combine, and have promptly returned fluid path 5.Between bubble 301 and air, be connected the slightly withdrawal to greatest extent of back meniscus 11.After this, drop is injected shown in Fig. 3 (e)-(g).Then, record liquid recharges nozzle 4 and stabilisation.

Consider the above process, as long as be retained in being connected of liquid maintenance in the nozzle and the liquid that is withdrawn into fluid path from nozzle after being connected between bubble and the air, cause that then the interior liquid of the liquid that is retained in the nozzle and fluid path combines, and recharge nozzle at last, even recording liquid sticks to the end face of the nozzle imagination, this liquid also combines with the above-mentioned record liquid that sticks to the nozzle inner surface.In other words, move backward to fluid path 5 even stick to the liquid of the nozzle end face of the imagination, the phenomenon that aforementioned record liquid can not be injected can not take place yet, and promptly writes down liquid and can spray reliably.

Liquid as the injected volume of drop 12 by the decisions such as jet size that are used for the fluid jetting head that liquid sprays.Under the situation of fluid jetting head in the present embodiment, make the volume of drop 12 be not more than 15 * 10 ^-15m ³

One of required condition that permission bubble 301 and air are connected reliably is: the size of To+Tn≤heater.The size meaning of heater is Sh ^1/2, wherein Sh represents the size of the heater area of heating surface.If To+Tn 〉=Sh ^1/2Even bubble is connected with air, the value of (To+Tn) is big more comparatively speaking, and the factor that works for the connection between bubble and the air is with regard to the negative interaction of the balance in connecting.Thereby, (To+Tn) and Sh ^1/2Between suitable relation become required condition.In addition, if fruit To+Tn 〉=Sh ^1/2, do not allowing under bubble and the situation that air is connected recording liquid injected.In other words, one of prerequisite of the present invention does not exist.

The architectural characteristic of the fluid jetting head of the following stated is listed as embodiments of the invention, these embodiment guaranteed bubble be retained in after being connected with air aforesaid liquid in the nozzle keep with from nozzle to being connected of the aforesaid liquid of fluid path withdrawal, and this liquid that keeps contacting with the liquid of withdrawing from nozzle is with the liquid combination in the fluid path.

(1) if the vertical cross-section of nozzle becomes taper, then it is more effective, promptly crosses the end face center and crosses over the minimum range that the minimum range of the end face of the said nozzle imagination was shorter than the bottom surface of bottom center's leap said nozzle imagination.

Fig. 6 has described to have the vertical cross-section of the nozzle of above-mentioned vertical cross-section.Because nozzle is taper, thus on how much for the recording liquid that is retained in the nozzle inner surface be easier to keep with fluid path in being connected of ink.And, because the size of the bottom surface of the nozzle imagination is greater than the end face of the nozzle imagination, so more difficult for record liquid stopped nozzles.

(2) if the horizontal cross-section of nozzle is a star rather than circular or square, then it is more effective.In other words, record liquid remains on the inner surface of nozzle easily, and said process takes place easily.This is owing to following reason.Promptly, if the horizontal cross-section of nozzle is a star, then stick to the easy more maintenance of record liquid of nozzle segment and being connected of nozzle bottom liquid, and the level of significance size of nozzle when liquid sprays also is that the area that straight line surrounded to the angle determines in the adjacent star by connecting.

(3) curvature of meniscus

In order to make the liquid that is retained in the nozzle inner surface be easy to be connected, wish that the negative pressure that formed meniscus produces in fluid path is big as much as possible with liquid in the fluid path.In order to make meniscus produce bigger negative pressure, wish that the height of fluid path and cross section are as much as possible little, as long as the time that recharges does not too increase.

In order to strengthen desirable embodiment (1)-(3), special hope makes the bottom side of nozzle be easy to soak (nozzle is treated to hydrophily) by record liquid.

(4) be adhered to the liquid volume of fluid injector

In order to prevent the recording liquid stopped nozzles, wish to carry out a kind of control, make the liquid measure that is retained in the nozzle top, promptly too much liquid measure is as much as possible little.For such work, importantly the top of nozzle is handled giving its hydrophobicity, be bonded to each other and grow so prevent to stick to the small pieces liquid at sundry goods inner surface top.In other words, importantly make the top of nozzle inner surface scold water as much as possible.And in fact hydrophilic region is positioned at the top of scolding water of leaving nozzle.

Below, the factor of how spraying from the viewpoint of nozzle plate structure explanation decision liquid from the aforesaid liquid shower nozzle.

The liquid that is retained on the nozzle inner walls after record liquid sprays forms meniscus in nozzle.At this moment, the relative pressure P of record liquid is:

P=-γ(1/r1-1/r2)

r1＜r2→P＜0

r1＞r2→P＞0，

Wherein r1 represented the center of meniscus cross over the meniscus that forms in the nozzle minimum range 1/2, as seen this from above; R2 representative is corresponding to the radius of meniscus curvature (being parallel to fluid path and comprising the curvature in the meniscus cross section on the plane at meniscus center); And the γ representative is apart from the surface tension of liquid.The unlikely liquid lock that is recorded of nozzle when P＞0, even because recording liquid appears near the end face of the nozzle imagination, to pull to nozzle be difficulty comparatively to this liquid when the P＞0.

The value of r1 is proportional to nozzle diameter (≈ So ^1/2), and the value of r2 is proportional to thickness T o.

Based on above-mentioned relation, the present inventor has tested and has considered to prevent that nozzle is recorded the various fluid jetting heads of the structural requirement of the above-mentioned phenomenon that liquid blocks, and promptly crosses over the minimum range of nozzle level cross-sectionn and the requirement of nozzle plate thickness about crossing cross-section center.Found that, even the liquid after bubble is connected with the air diameter in the fluid path does not contact with the bottom surface of the nozzle imagination, above-mentioned phenomenon, being nozzle is blocked the ratio that takes place by distance liquid, and to double the some place of nozzle plate thickness different significantly crossing minimum range that kernel of section passes through the nozzle horizontal cross-section.In other words, served as that minimum range that kernel of section passes through the nozzle horizontal cross-section doubles nozzle plate thickness or when bigger (if the end face of the nozzle imagination and the distance between the bottom surface be not more than kernel of section pass through the nozzle horizontal cross-section minimum range half), the ratio that then above-mentioned phenomenon takes place is low-down.Otherwise, if cross the thickness that minimum range that kernel of section passes through the nozzle horizontal cross-section is not more than the twice nozzle (if the distance of asking of the end face of the nozzle imagination and bottom surface be not less than kernel of section pass through the nozzle horizontal cross-section minimum range half), the ratio that then above-mentioned phenomenon takes place is very high, and is promptly high as to be enough to throw into question with regard to actual the use.

Among the present invention,, then " cross the minimum range that kernel of section passes through the nozzle horizontal cross-section " and can be defined as the diameter of the virtual circular horizontal cross of nozzle if nozzle is real circle perpendicular to the above-mentioned horizontal cross-section of distance liquid injection direction substantially.If the horizontal cross-section of nozzle is square, then it may be defined as the length on one of four limits; If be rectangle, then may be defined as the length of minor face; If be oval, then may be defined as its length of short diameter; And if the vertical cross-section that is parallel to the nozzle of injection direction is taper, then it may be defined as the minimum range that nozzle passes through in nozzle center.

Below will illustrate with the required condition of high-frequency drive fluid jetting head.For with the high-frequency drive fluid jetting head, the time of recharging must lack.The time that recharges is by following conditional decision: the maximum of (1) meniscus withdrawal, (2) be as driving the capillary force that liquid recharges power, and (3) recharge during the viscous resistance of liquid.

The maximum of meniscus withdrawal (1) is more little, and it is short more to recharge the time.Like this, as long as can spray volume required drop reliably, wish that the withdrawal amount of meniscus is as much as possible little.In order to satisfy this requirement, wish that the duration that driving pulse is set is not more than 3.5 microseconds.

Capillary force (2) is in the power that recharges drive China ink liquid, so thereby, in general, wish big as far as possible.In other words, wish that the capillary force of recording liquid is high as far as possible, preferably be not less than 0.025N/m.

In general, wish that the viscous resistance (3) of fluid path is as far as possible little.

Above-mentioned condition is in order to make the aforesaid liquid in the fluid path be easy to keep the liquid with being retained in the nozzle inner surface to be connected.Thereby, when these conditions satisfy, can spray record liquid more reliably according to fluid jetting head of the present invention.

The viscous resistance (3) that should be noted in the discussion above that capillary force (2) and fluid path must be provided with like this, makes that finishing the vibration that recharges the back meniscus can not become excessive.

About fluid path viscosity resistance during recharging, be reduced to and have been found that with the condition of high-frequency drive the height of fluid path must be necessary for 6 μ m or littler by Tn according to the real standard of fluid jetting head of the present invention; 6 μ m≤Tn.If 6 μ m 〉=Tn, if promptly the height of fluid path too reduces, then the viscosity of fluid path increases, and has prolonged the time that recharges, and thereby can not be with the high-frequency drive fluid jetting head.For the viscosity that keeps fluid path is low, then must use the not really high recording liquid of its viscosity.In other words, the viscosity of wishing recording liquid is not more than 5 * 10 ^-2N/s.

In order to print a desirable image by the distortion factor, promptly the little image of its amount distortion wishes that the speed that drop sprays is not less than 10m/ second and is not more than 30m/ second, preferably is not less than 10m/ second and is not more than 20m/ second.If the speed that drop sprays is less than 10m/ second, then drop may be lost the point that will print on the recording medium, and this may reduce print quality.If jet velocity surpasses 30m/ second, the drop that then sprays possibility splash also forms litura when their bump recording mediums.And even satisfy above-mentioned condition about liquid jeting speed, if too reduce the thickness of nozzle plate, it is unstable that the direction that drop sprays may become, and also may reduce the mechanical strength of nozzle plate 3.Nozzle plate needs a certain amount of thickness like this.More particularly, the thickness of nozzle plate need be not less than 4 μ m.

Fluid jetting head according to the above embodiment of the present invention for example can be installed in the liquid injection apparatus as shown in Figure 4, to implement according to liquid jet method of the present invention.

One example of liquid injection apparatus is described hereinafter with reference to Fig. 4.

With reference to Fig. 4, label 200 represents removably to be equipped with on it balladeur train of above-mentioned fluid jetting head.In this liquid injection apparatus, used four fluid jetting heads holding the black liquid of different colours, and together be contained on the balladeur train 200 with yellow ink liquid China ink liquid container 201Y, magenta ink liquid China ink liquid container 201M, cyan ink liquid China ink liquid container 201C and black ink liquid China ink liquid container 201B.

Balladeur train 200 is supported by the axis of guide 203, and enables by being shuttled back and forth along guide shaft 202 forward and to the endless belt 204 of rear drive by motor 203.Endless belt is wound on

pulley

205 and 206.

As the recording paper P of recording medium arrow B indication perpendicular to the direction of direction A on transmitted periodically.Pair of

rolls

209 and 210 clampings below record-paper P is reached by top pair of

rolls

207 and 208, thus a certain amount of tension force provided, make it when being transmitted, keep smooth.Roller unit is driven by drive part 211.Yet this device can be constructed like this, makes roller unit by above-mentioned Motor Drive.

And on demand, each printing begins balladeur train 200 and stops at the position of stopping.The enclosure element 212 that is used to four statures to add a cover one by one is positioned at position of rest.Enclosure element 212 is connected with vacuum plant, and this device prevents nozzle blockage by nozzle is vacuumized.

(embodiment 1 and 2)

Produce Fig. 2 (a) with (b) shown in fluid jetting head and its performance tested.Its result provides in table 1.As Fig. 1 (a) with (b), nozzle arrangement in parallel two row, the nozzle in the delegation at line direction to the nozzle dislocation half pitch in another row.More particularly, at each row, nozzle is with 300dpi spacing configuration, and the nozzle in the delegation is to nozzle of another row 25.4mm that misplaces on line direction.In other words, nozzle resembles and arranges the footprint of bird.Thereby, be 600dpi (every 25.4mm has 600 nozzles) in density perpendicular to the direction top nozzle of shower nozzle preliminary sweep direction.Crossing the minimum range that kernel of section passes through the nozzle horizontal cross-section is 22 μ m, and the shaping of nozzle makes its horizontal cross-section become rectangle.The size So of the opening of each nozzle is 484 μ m ²(=22 μ m * 22 μ m).With regard to this specification, in the liquid flow path direction effectively the bubble length that produces the zone be 26 μ m, and be 13 μ m to the distance that effective bubble produces edges of regions at liquid supply source one side produces the zone from effective bubble center.The size of the heating surface of each heater is 936 μ m ²(=26 μ m * 36 μ m).

In embodiment 1 and 2, the height Tn of flow channel becomes 12 μ m and 6 μ m respectively, and the thickness T o of nozzle plate makes 9 μ m and 11 μ m respectively.And, the electrical insulating film (SiO of formation 0.6 μ m thickness on each heater surfaces ₂) and 0.3 thickness passivating film (Ta).

As for recording ink liquid, use by the following black liquid of forming:

TiO hexylene glycol 15%

Glycerine 5%

Urine 5%

Isopropyl alcohol 4%

Water all the other

China ink liquid viscosity is 1.8 * 1 ^-2Surface tension is 0.038N/m, and density is 1040kg/m ³

More than Gou Zao fluid jetting head (record head) uses and can drive with 7kHz to the power supply that heater is executed 12V voltage Vop.The driving pulse duration is 1.9 microseconds.When the driving pulse duration that is applied to heater was 1.9 microseconds, the minimum voltage Vth (threshold voltage) that black liquid is sprayed was 9.9V.Thereby Vop/Vth is 1.21.When shower nozzle was driven under these conditions, the performance or the characteristic that are realized about this shower nozzle each side provided in table 1.

Table 1

Embodiment 1 embodiment 2 Comparative Examples 1 Comparative Examples 2 Comparative Examples 3 Comparative Examples 4Sh (μ m ²) 936 the same the same So (μ m ²) 484 the same 441 484

(22 μ m * 22 μ m), (21 μ m * 21 μ m), (22 μ m * 22 μ m) D, (μ m) 22 the same 21 22Tn, (μ m) 12 6646 5.5To, (μ m) 9 11 12 9 11 11 moves qualitative good OK bad not OK Vol 8.2 7.7 7.5 7.2 7.4 7.9, (10^-10m ³) speed (m/s) 15.8 17.3 18.0 19.1 17.7 17.8 recharges 75 129 146 280 127 159 times (μ sec) and suitably be extended to 170 6 0.2 0.4 0.7 0.2D/To 2.44 2.0 1.83 2.44 1.91 2.0

Under these conditions, carried out printing, the paper of wherein supplying with many A3 specifications continuously is a record-paper.The minimum span of crossing the nozzle of nozzle center is 22 μ m, and this is apart from the twice of the nozzle plate thickness of nozzle end face that is not below or equal to the imagination and the distance between the bottom surface.Its performance is, printing can be carried out across the whole A3 paper of record-paper, and is uninterruptedly to carry out, and this has surpassed performance level no problem in the actual use.In other words, shower nozzle is reliable.

Shower nozzle enough fast and situation that China ink liquid viscosity increases can adapt to shower nozzle and do not use the time on black liquid jet velocity.More particularly, shower nozzle can adapt to viscosity up to 5 * 10 with meeting the requirements ^-2The black liquid of N/m.When black liquid viscosity increase and above 10 * 10 ^-2During N/m, promptly when black liquid viscosity is too high, black liquid jet velocity drops to and is lower than 10m/ second.Consequently, black liquid is lost the point that should print on recording medium.In order to guarantee to realize purpose of the present invention, wish that the surface tension of black liquid is high as far as possible.Yet, except black liquid jet velocity, must consider also how ink droplet moves the surface tension that decides black liquid during record-paper at its bump.So, wish that the surface tension of black liquid is not less than 30 * 10 ^-2N/m, and as long as black liquid can be by hope by bubble jet, then to the upper limit without limits.If the surface tension of black liquid is less than 30 * 10 ^-2N/m, then the capillary force that is produced by black liquid is not high enough and be not enough to as driving the power that black liquid recharges.So the time of recharging is long, and the chien shih shower nozzle can not become problem with high-frequency drive during long recharging.

In above embodiment, apply from the liquid injection pulse that to begin to count the time of recharging be 75 microseconds.After this meniscus oscillations be in detection less than level, and in fact to not influence of print quality.

In these embodiments, also form thin heater protective film, and the short pulse duration is set.So the bubble growing amount is relatively little.In other words, recharge speed by minimizing meniscus withdrawal amount rather than increase and reduced the time of recharging.

The overcoat of heater 1 in addition, is by SiO ₂(0.6 μ m is thick) that forms, and passivating film (0.3 μ m is thick) is formed by Ta.As long as suitable length of heater duration wishes that these films are thin as far as possible.The thickness that reduces overcoat allow to be reduced in pulse apply beginning and air bubble growth begin between from the heat of heater to black liquid conduction.Thereby the thickness that reduces overcoat can be reduced in the increment that bubble produces the back bubble, thereby reduces meniscus withdrawal amount.When overcoat by SiO ₂Or SiN wishes that its thickness is not more than 1 μ m when forming.Significantly, if material such as erosion-resisting platinum is used as heater material especially, then crosses over and save overcoat.

In fluid jetting head according to the present invention, wherein the bubble that produces in the fluid path is connected with air by nozzle, and each volume that sprays the black liquid that is sprayed is generally determined by the geometric aspects of heater, fluid path and nozzle.In other words, a wide scope is arranged in the air bubble growth amount, each black liquid that is sprayed that sprays amasss the influence that not reduced by air bubble growth in this scope.

(comparative example 1-4)

Employed similar in employed fluid jetting head and embodiment 1 and 2 among the Comparative Examples 1-4, institute's difference is that in these comparison example, the height of fluid path changes to embodiment 1 and 2.In other words, in embodiment 1 and 2, the height of fluid path Tn is 12 μ m and 6 μ m, and among the Comparative Examples 1-4, this is 6 μ m, 4 μ m, 6 μ m and 5.5 μ m accordingly.In comparison example, the thickness T o of nozzle plate is 12 μ m, 9 μ m, 11 μ m and 11 μ m accordingly.And cross the twice of the horizontal minimum range of each nozzle opening of nozzle center less than nozzle plate thickness T o.

In Comparative Examples 1 and 3, wherein be set to equal the thickness T o of the nozzle plate of the end face of each nozzle imagination and the distance between the bottom surface, greater than crossing half of the horizontal minimum range D of open centre nozzle opening, the fluid jetting head frequency can not atomizing of liquids, or the like.In comparison example 2 and 4, wherein the height of fluid path recharges time span and makes fluid jetting head be unsuitable for high-frequency drive less than 6 μ m.

Though this does not have record in table 1, if value (To+Tn) is greater than Sh ^1/2(≈ 31 μ m), then the behavior of drop and meniscus becomes unstable when bubble is connected with air, and this has negative influence to print quality.

(embodiment 3-5 and comparison example 5-10)

Production drawing 2 (a) and (b) shown in fluid jetting head, and its performance tested.The result provides in table 2.As Fig. 1 (a) with (b), nozzle arrangement is in two parallel row.More particularly, at each row, nozzle is with 600dpi spacing configuration, and the nozzle in the delegation is to nozzle of another row half pitch that misplaces on line direction.In other words, nozzle resembles and arranges the footprint of bird.Thereby, be 1200dpi in density perpendicular to the direction top nozzle of shower nozzle preliminary sweep direction.The opening size of each nozzle is 227 μ m among the embodiment 3-5 ²(=φ 17 μ m), 225 μ m ²(=15 μ m squares), and 234 μ m ²In each embodiment 3-5, the big or small Sh of the area of heating surface of each heater is 576 μ m ²(24 μ m * 24 μ m).

In embodiment 3-5, use as employed identical black liquid among the embodiment 1 and 2.

As for the height Tn of each fluid path, in

embodiment

3 and 4, make 12 μ m, and be 6 μ m in embodiment 5.About the thickness T o of nozzle plate, in embodiment 3, make 7 μ m.And be 6 μ m in embodiment 4.In embodiment 5, it is made into 9 μ m.

In Comparative Examples 5-10, the size of each nozzle is made 200 μ m accordingly ², 324 μ m ², 227 μ m ², 202 μ m ²(=14.2 μ m squares), 324 μ m ²And 324 μ m ²It is identical with embodiment 3-5 that the size Sh of the heating surface of each heater makes, and this is 576 μ m ²(24 μ m * 24 μ m).The height Tn of each fluid path becomes 12 μ m, 4 μ m, 8 μ m, 12 μ m, 6 μ m and 5.0 μ m accordingly among the Comparative Examples 5-10, and the thickness T o of each nozzle becomes 9 μ m, 11 μ m, 9 μ m, 9 μ m, 9.5 μ m and 9 μ m accordingly.

The sheet resistance of heater is 53 ohm.

More than Gou Zao fluid jetting head (record head) uses and can drive with 10kHz to the power supply that heater applies 9.0V voltage Vop.The duration of each driving pulse is 2.7 microseconds.When the duration of the driving pulse that is applied to heater was 2.7 microseconds, making black liquid spray necessary minimum voltage Vth (threshold voltage) was 7.2V.Thereby Vop/Vth is 1.25.When this shower nozzle was driven under above-mentioned condition (9V/2.7 microsecond), performance or the characteristic about the each side of this shower nozzle that are realized, and continuous recording paper (A3 record sheet) number of the printing by its black liquid normal injection provided in table 2.

Table 2

Embodiment 3 Comparative Examples 5 Comparative Examples 6 Comparative Examples 7 Comparative Examples 8 embodiment 4 embodiment 5 Comparative Examples 9 Comparative Examples 10Sh (μ m ²) 576 the same the same the same the same the same the same the same the same

(24 μ m * 24 μ m) So (μ m ²) 227 200 314 227 202 225 324 the same the same

(14.2μm×?(15μm×

14.2 μ m) 15 μ m) whether the same Tn (μ m) 12 12 48 12 12 66 5To (μ m) 79 11 9969 9.5 9 of D (μ m) φ 7 φ 6 φ 20 φ, 17 14.2 15 φ 18 move qualitative OK bad good OK bad Vol. 4.5 4.3 4.2 4.1 4.4 4.2 4.8 4.9 4.1 (10 or not^-10m ³) speed, (m/s) 17 15 18 14 15 17.5 16 16 18 recharged for 92 90 920 95 89 86 102 101 158 times, (μ sec) suitably is extended to 110 0.1 0.05 0.2 0.05 110 5 0.8 0.3D/To 2.4 1.78 1.82 1.89 1.58 2.5 2.0 1.89 2.0

From table 2 obviously as seen, among the embodiment 3-5, the continuous recording paper number of pages of the printing by its black liquid normal injection is far longer than than Comparative Examples son.This has proved that the present invention has successfully prevented the appearance of undesirable white line, and this white line will occur if some nozzle can not spray black liquid.

Note D/To, in embodiment 3-5, D/To is not less than 2, and it is not more than 2 in Comparative Examples 5-9.And in Comparative Examples 5-9, the number of the recording occurring continuously page of the printing by its black liquid normal injection is little, and, be tangible owing to spraying unsuccessful undesirable white line.Like this, wish that D/To is not less than 2.In Comparative Examples 10, D/TO is 2.0, and the frequency of injection failure suddenly is relatively little.Yet in this comparison example 10, the height Tn of each fluid path is 5.0 μ m, and this is quite low.Thereby when shower nozzle drove with 10kHz or higher frequency, fluid path can not enough be filled apace, thereby image color is than normal print visual shallow.In other words, the continuous recording paper number of pages by its black liquid normal injection is little.

As for recharging the time, in comparison example 7, it is 95 microseconds, and this is for being enough fast with above-mentioned frequency drives shower nozzle.Yet in Comparative Examples 6, it is 920 microseconds, and this is fast inadequately for the 10kHz driving frequency.This is due to the fact that promptly in comparison example 6, Tn is 4 μ m, and this is quite little.So,, wish that then height Tn is not less than 6 μ m as long as consider to recharge the time.

In embodiment 4 and comparison example 8, the opening of each nozzle is square, and this shape with other embodiment and comparison example is different, and they are proper circle shapes in those examples.Even at its nozzle opening is in the comparison example 6 of proper circle shape, with the opening of other nozzle be that the shower nozzle of proper circle shape can spray unexpected failure equally.In embodiment 4, D/To is desirable 2.5, because this is greater than 2.Even the opening of nozzle is square, can not spray unexpected failure yet.The distortion that the pressure that consideration is produced by bubble causes wishes that the thickness T o of nozzle plate is not less than 4 μ m.

In addition,, activate fluid jetting head like this, make each record sheet cover " complete " with black liquid for regard to color depth and injection unexpected failure exact evaluation the foregoing description and Comparative Examples, and evaluation result.The meaning that quilt " complete " covers is that the printable area 100% of each record sheet is covered by ink dot.In this test, supply with the record sheet of many A3 specifications (JIS) continuously.Importantly be used to estimate the standard of fluid jetting head, promptly whether fluid jetting head can normally spray black liquid, so that cover the record sheet supplied with continuously integral body one of at least with black liquid.If color depth is opened decline when given fluid jetting head covers record sheet whole with black liquid, or failure (shower nozzle is unacceptable) is sprayed in appearance suddenly, judge that then this shower nozzle can not use, because under this situation, must interrupt printing with recovery operation of needing extra time etc.In other words, to guarantee importantly that do not interrupt and do not lose print quality, fluid jetting head can integrally cover at least one (A3) record sheet with black liquid.

In any case, with regard to fluid jetting head structure and liquid jet method, to being not more than 15 * 10 when volume ^-15m ³The problem of ink droplet appearance during from this fluid jetting head injection that allows that bubble is connected with air, the invention provides practical solution.

(other)

When putting on based on the record head of ink-jet and during based on the tape deck of ink-jet, particularly those are equipped with and as the device of the heat energy of the energy that is used to spray black liquid (for example are used to produce, electric transducer, laser beam radiated element etc.), and using heat energy to change the device of black liquid status, the present invention has produced outstanding result.This is due to the fact that, promptly according to this black liquid spraying system, can write down to produce high-precision image with high density.

As for the structure and the liquid ejector principle of this record head and tape deck, at U.S.PatentNo.4,723,129 and 4,740, what revealed in 796 the application specification is needed.The system that is revealed in these patents is compatible with so-called request response type and continous way both, particularly owing to following reason and request response type compatibility.That is, in the request response type, each electric transducer is towards paper or the fluid path configuration of wherein possessing liquid (black liquid).In order to spray black liquid, apply a signal according to record data to electric transducer at least, this signal can produce enough big thermal energy on the surface of electric transducer, so that suddenly fluid temperature is increased to the so-called film boiling point that is excited in the liquid.In other words, in liquid (black liquid), form bubble by driving signal one by one.At each air bubble growth and when contacting, liquid is injected by the opening corresponding to the specific nozzle of record data with the form of drop (at least one drop).Drive the preferably form of pulse of signal, grow immediately and suitably and contact because the driving signal of impulse form causes bubble, in other words, shower nozzle responds fine when driving signal and be impulse form.

More particularly, such as at U.S.Patent No4, the sort of driving signal of driving signal of the impulse form of revealing in 463,359 and 4,345,262 is suitable for.And, if adopt U.S.PatentNo4, the condition of advancing the speed about the hot emission surface temperature of electric transducer that is write down in 313,124 the specification, then print quality can further be improved.

The present invention not only can with the recording head structure compatibility of being revealed in each in the above-mentioned patent specification, wherein nozzle, fluid path (right angle fluid path) and electric transducer are arranged as mentioned above, but also can with such as U.S.Patent No4,558,333 and U.S.Patent No4, the record head compatibility of the recording head structure of being revealed in 459,600 the specification is positioned at the sweep of fluid path according to the hot emission surface of this structure electric transducer.When being used for the recording head structure that Japanese Laid-Open Patent Application No.123670/1984 revealed, the present invention also is effective, according to this structure nozzle is to be made of the line of rabbet joint that a plurality of electric transducers are shared, perhaps the recording head structure of being revealed among the Japanese Laid-Open Patent Application No.138461/1984 absorbs the opening of the pressure wave that is produced by heat energy directly in the face of the liquid ejecting portion configuration according to this structure.In other words, the present invention has improved such as above-described record head with regard to reliability and validity aspect, no matter and its structure how.

And then the present invention can be effective to entirely to go the type record head, and promptly its length equals the record head of tape deck dominant record scope length, in other words, but the width of the image posting field of the accessible the most large stretch of recording medium of tape deck.Full line item head can be by the constituting of a plurality of record heads, and the length of its combination equals the length of full line item head, or can be used as a whole long record head and form.

It may be the serial type record head of fixed record head form that the present invention can also be effective to above-mentioned, chip record head, or box type record head.The fixed record head is the sort of record head that is fixed in the tape deck primary clustering.The chip record head is the detachable record head that detachably is installed in the tape deck primary clustering.When record head was installed in the primary clustering of tape deck, it was electrically connected with master component, and is supplied to black liquid.The box type record head is the sort of record head that integral body comprises black liquid container.

Wish to provide the record head that has the jet performance recovery device, is used for before record sprays, spraying the device etc. of black liquid, because this can guarantee validity of the present invention.More particularly, these devices are device, the devices that are used to clean record head of being used for the housing record head, be used for to record head apply positive or negative pressure device, be used for heating record head or the device of black liquid and the device that is used for before record sprays, spraying black liquid before record sprays.The device that is used for before record sprays heating record head or black liquid can adopt the electric transducer that is used to write down injection, is different from the electric transducer that record sprays usefulness, perhaps both combinations.

There is not strict restriction about record head type and the record head number that is installed in the tape deck.For example, the record head number that is installed in the tape deck can have only one, as under the situation of the tape deck of just printing with monochromatic mode, perhaps can be a plurality of, as in the situation of using the different image of multiple black liquid print colors or concentration.In other words, the present invention not only can be used for only being equipped with the tape deck of single record head as leading watermark patterns or black mode very effectively, but also be applicable to that a plurality of record heads integrated each other or that separate are housed is used for the tape deck printed with multiple logging mode, for example the broken colour pattern, can comprise full color mode of monochromatic mode or the like by what blend of colors realized.

In the above explanation to embodiments of the invention, China ink is depicted as liquid ink liquid form.Yet the present invention is applicable at normal room temperature or is lower than that normal room temperature remains solid and at the China ink that is being higher than normal room temperature liquefaction.In general, in ink-jet system, for the viscosity that keeps black liquid in stable scope is kept in ink-jet, control temperature and it be remained on be not less than 30 ℃ to not being higher than in 70 ℃ the scope.Like this, the China ink that together uses with tape deck according to the present invention can be the sort of China ink of liquefaction when tracer signal applies.Use " solid " China ink that extra benefit is provided.For example, the increase by the too much temperature using too much energy can prevent to cause by too much energy from the solid-state state that changes China ink to liquid state.Can adopt and remain solid-state and at the China ink of liquefaction when it heats, so that prevent China ink evaporation at idle state.In any case, the present invention can be applicable to the China ink of above-described any kind, for example has only the solid ink that just liquefies by the heat energy that is produced by tracer signal, and this China ink sprays with liquid form, but begins to solidify when it arrives recording medium.An example of this China ink reveals in Japan postpones publication application No.56847/1979 or 71260/1985, and according to this example, solid-state or liquid ink is retained in recess or the hole by porous materials film, makes it directly towards electric transducer.Just compatible with such China ink, be best based on the record head of above-mentioned film boiling type system.

As for the scope of using, inkjet-type recording device according to the present invention can be used as such as the visual outlet terminal of the such information processor of computer, with the copy device of combination such as reader, be provided with the facsimile machine of receiving and dispatching two kinds of functions etc.

Though describe the present invention with reference to the structure of being revealed here, it is not limited to described details, and the application is intended to cover those modifications and variations that are included in claim scope within the improved order or following.

Claims

1. use the liquid jet method of fluid jetting head, this fluid jetting head has and is used for producing enough heat energy so that generate the electric transducer element of bubble at liquid, and the jet exit of facing the electric transducer element configuration, they are arranged in delegation to be not less than the individual density of every 25.4mm300, fluid jetting head also has the flow channel with the jet exit fluid connection respectively, the bubble that generates of the heat energy that produces by electric transducer element wherein, make it and air communication during in the bubble internal pressure, and wherein spray and be not more than 15 * 10 with the frequency that is not less than 7kHz less than atmospheric pressure ^-15m ³The drop of volume, described method is comprising improvement:

The height of the flow channel of fluid jetting head is not more than 6 μ m, and the distance between jet exit upper surface and the lower surface is not more than minimal openings distance by the jet exit center half.

2. according to the process of claim 1 wherein the size upper surface of jet exit and the distance between the lower surface and flow channel height and that be not more than electric transducer.

3. according to the process of claim 1 wherein that the volume of drop is not more than 10 * 10 ^-15m ³

4. according to the process of claim 1 wherein that the height of flow channel is not more than 20 μ m.

5. according to the process of claim 1 wherein that the jet velocity of the drop that sprays is not more than 20m/s.

6. according to the process of claim 1 wherein that the width that puts on the electric pulse of described electrothermal transducer element for atomizing of liquids is not more than 3.5 μ sec.

7. according to the process of claim 1 wherein that the driving voltage that puts on given electric pulse is in 1.1 times of-1.3 times of scopes of the threshold voltage that drop sprays.

8. according to the method for claim 7, wherein said electric pulse comprises a plurality of pulses.

9. method according to Claim 8, wherein said a plurality of pulses comprise a main pulse and the preamble pulse that applied before main pulse, and the duration of preamble pulse is not more than 1.5 μ sec.

10. according to the method for claim 9, the interval between wherein said main pulse and the described preamble pulse is not more than 2.0 μ sec.

11. according to the method for claim 11, wherein the liquid that is sprayed has surface tension that is not more than 0.025N/m and the viscosity that is not more than 5 * 10-2N/s.

12. according to the process of claim 1 wherein that described electrothermal transducer element produces the film boiling that heat energy is enough to cause liquid.

13. use a kind of fluid jetting head of fluid jetting head, this fluid jetting head has and is used for producing enough heat energy so that generate the electric transducer element of bubble at liquid, and the jet exit of facing the electric transducer element configuration, they are arranged in delegation to be not less than the individual density of every 25.4mm300, fluid jetting head also has the flow channel with the jet exit fluid connection respectively, the bubble that generates of the heat energy that produces by electric transducer element wherein, make it and air communication during in the bubble internal pressure, and wherein spray and be not more than 15 * 10 with the frequency that is not less than 7kHz less than atmospheric pressure ^-15m ³The drop of volume, described shower nozzle is comprising improvement:

14. according to the fluid jetting head of claim 13, the size wherein upper surface of jet exit and the distance between the lower surface and flow channel height and that be not more than electric transducer.

15. according to the fluid jetting head of claim 13, wherein the volume of drop is not more than 10 * 10 ^-15m ³

16. according to the fluid jetting head of claim 13, wherein the height of flow channel is not more than 20 μ m.

17. according to the fluid jetting head of claim 13, wherein the jet velocity of the drop of Pen Sheing is not more than 20m/s.

18. according to the fluid jetting head of claim 13, wherein the width that puts on the electric pulse of described electrothermal transducer element for atomizing of liquids is not more than 3.5 μ sec.

19. according to the fluid jetting head of claim 19, the driving voltage that wherein puts on given electric pulse is in 1.1 times of-1.3 times of scopes of the threshold voltage that drop sprays.

20. according to the fluid jetting head of claim 19, wherein said electric pulse comprises a plurality of pulses.

21. according to the fluid jetting head of claim 20, wherein said a plurality of pulses comprise a main pulse and the preamble pulse that applied before main pulse, and the duration of preamble pulse is not more than 1.5 μ sec.

22. according to the fluid jetting head of claim 21, the interval between wherein said main pulse and the described preamble pulse is not more than 2.0 μ sec.

23. according to the fluid jetting head of claim 13, wherein the liquid that is sprayed has surface tension that is not more than 0.025N/m and the viscosity that is not more than 5 * 10-2N/s.

24. according to the fluid jetting head of claim 13, wherein said electrothermal transducer element produces the film boiling that heat energy is enough to cause liquid.

25. use the liquid jet method of fluid jetting head, this fluid jetting head has and is used for producing enough heat energy so that generate the electric transducer element of bubble at liquid, and the jet exit of facing the electric transducer element configuration, they are arranged in delegation to be not less than the individual density of every 25.4mm300, fluid jetting head also has the flow channel with the jet exit fluid connection respectively, the bubble that generates of the heat energy that produces by electric transducer element wherein, make it and air communication during in the bubble internal pressure, and wherein spray and be not more than 15 * 10 with the frequency that is not less than 7kHz less than atmospheric pressure ^-15m ³The drop of volume, described method comprises:

First step, wherein after the air communication of liquid and bubble, stay liquid in the jet exit keep with flow channel in from the fluid connection of the liquid of jet exit withdrawal;

Second step wherein makes the liquid that stays combine so that liquid is recharged jet exit with liquid in the flow channel.

26. according to the method for claim 25, the size wherein upper surface of jet exit and the distance between the lower surface and flow channel height and that be not more than electric transducer.

27. according to the method for claim 25, wherein the outer surface that forms jet exit being handled is hydrophily.

28. according to the method for claim 27, the outer surface that wherein forms jet exit has the part hydrophilic area.

29., be the inner surface treatment that forms jet exit hydrophily wherein according to the method for claim 25.