CN1150777A - A liquid ink printing apparatus and system - Google Patents

Abstract

A new printing system is disclosed for drop on demand printing. This printing mechanism divides the printing process into two stages; a drop selection means to select drops to be printed which generates a difference in meniscus position between selected drops and unselected drops of fluidized ink; and a drop separation means, attracting the ink of said drops to a substrate, the attraction being insufficient to overcome the surface tension of drops in an unselected meniscus position but being sufficient to overcome the surface tension of drops in a selected meniscus position so as to cause movement of the drops to the substrate. The drop selection means can produce a difference in meniscus position in the absence of the drop separation means. The separation of drop selection means from drop separation means significantly reduces the energy required to select which ink drops are to be printed. Only the drop selection means must be driven by individual signals to each nozzle. The drop separation means can be a field or condition applied simultaneously to all nozzles.

Description

Liquid ink printing apparatus and system

Invention field

The present invention relates to computer-controlled PRN device field. Concrete field is the print head structure of throwing in as required (DOD) print system.

Background of invention

At present many dissimilar digital control print systems have been invented, and many kinds of products are arranged at present. These print systems are used various driving mechanisms, various printed material and various recording medium. The example of the digital printing system that uses at present comprises: electronic laser photograph printer; LED electrophotographic printer; Dot matrix impacts printer; The heat-sensitive paper printer; Film recorder; The thermoplastic printer; Dyestuff scatters thermal transfer printer; And ink-jet printer. Yet, being worth although just have coml when this customary way needs expensive equipment and only has thousands of pages of duplicate of the printing of needs, this electron-like print system can not replace the mechanical art of printing effectively. Therefore need to improve numerically controlled print system, for example need and in high speed and to produce high-quality coloured image with common paper under the condition cheaply.

Inkjet printing is considered to an outstanding competitor in numerically controlled electronic printing field, because it has without impacting, low noise characteristic is used common paper, and can avoid transfer printing and the photographic fixing of toner.

Many kinds of inkjet printing mechanisms have been invented. They can be classified into continous inkjet (CIJ) or throw in as required (DOD) ink-jet. The printing technique of continous inkjet can be traced back to nineteen twenty-nine at least: the patent US1 of Hansell, 941, No. 001.

The people such as Sweet are at patent US3 in 1967, disclose a kind of array of continous inkjet nozzle in 373, No. 437, need the ink droplet of printing to be injected selectively and towards recording medium deflection. This technology is called as binary system deflection CIJ, and is included Elmjet and Scitex adopts in interior many manufacturers.

The people such as Herhz are at patent US3 in 1966, disclose a kind of method that realizes the varying optical density of print point in CIJ prints in 416, No. 153, adopt static to disperse the ink droplet stream that injects, thereby modulation are by the ink droplet quantity of aperture. This technology is used in the ink-jet printer of Iris Graphics manufacturing.

The people such as Kyser are at patent US3 in 1970, disclose a kind of DOD ink-jet printer in 946,398, and it applies high voltage to piezo-electric crystal, makes crystal crooked, thereby exert pressure and spray on demand ink droplet at ink reservoir. Invented subsequently the printer that many kinds of piezoelectric types are thrown in as required, they have utilized bending shape, propelling form, shearing form and the extruding form of piezo-electric crystal. Use the piezoelectricity DOD printer of hot melt printing ink to obtain coml success (for example Tektronix and Dataproducts printer), and make family expenses and the image resolution ratio of handling official business with printer reach 720dpi (Seiko Epson). The advantage of piezoelectricity DOD printer is to use many kinds of printing ink. Yet the piezoelectric printer structure needs complicated high-voltage driving circuit and heavy piezo-electric crystal array usually, and this requirement is imperfect in manufacturing process and aspect of performance.

The people such as Eodo are at patent GB2 in 1979, disclose a kind of electric heating DOD ink-jet printer in 007, No. 162, it to nozzle in the printing ink electric transducer (heater) that forms thermo-contact apply electric pulse. Heater is heated to rapidly very high temperature to moisture printing ink, makes a small amount of printing ink evaporate rapidly the formation bubble. The formation of these bubbles produces pressure wave, and the ink droplet that makes printing ink sprays from aperture along the edge of heater substrate. This technology is called as Bubblejet^TM(trade mark of Japanese Canon K.K.), and be widely used in from Canon, in the printer system of Xerox and other manufacturers.

The people such as Vaught are at the patent US4 of nineteen eighty-two, disclose a kind of electrical heating ink droplet spraying system in 490,728, and it also operates by forming bubble. In this system, ink droplet sprays by being located at the nozzle that is arranged in the perforated panel above the heater on perpendicular to the direction of heater substrate plane. This system is called as Thermal Ink Iet, is made by Hewlett-Packard. In this article, this term of Thermal Ink Jet is used to represent the Hewlett-Packard system and is commonly referred to Bubblejet^TMSystem.

Typical Thermal Ink Jet is printed on needs about 20 μ J (heat) in cycle of the about 2 μ s that spray each ink droplet. Each heater need to consume 10 watts driving power, and this is its shortcoming, and needs special-purpose printing ink, complicated drive circuit, and heating element is easy to damage.

The ink-jet print system that other in technical literature, also occurred, but unpopular in market at present. For example US Patent No. 4,275, and disclosed a kind of system in No. 290 when the predetermined print-head nozzle of receiving thermal pulse is consistent with the address of static pressure, just makes printing ink freely flow on the paper that separates with pad below printhead. In US Patent No. 4,737,803; 4,737,803 and 4,748, in the disclosed inkjet printing register system, when the printing ink in the print-head nozzle of receiving thermal pulse was consistent with the address of electrostatic attraction field, ink droplet just was injected on the printing paper in No. 458.

Each own pluses and minuses separately of above-mentioned ink-jet print system. Yet, generally also think in other respects and need to improve inkjet technology, need improved problem that the simplification of price, speed, quality, reliability, power consumption, structure and operation, durability and running stores etc. are for example arranged. Summary of the invention

An object of the present invention is to provide the print system of liquid ink, this system has obvious progress towards above-mentioned improvement direction. The invention provides a kind of printing mechanism of throwing in as required, wherein select the device of printed dot between selected ink droplet and unselected ink droplet, to produce an alternate position spike with one, but this alternate position spike deficiency is so that ink droplet overcomes the surface tension of printing ink and separates from the printing ink main body, and one of them attachment device can make above-mentioned selected ink droplet separate from above-mentioned printing ink main body.

A preferred version of the present invention is that the device that produces alternate position spike between selected ink droplet and unselected ink droplet relies on electrical heating to reduce the surface tension of pressurized printing ink.

Another preferred version of the present invention is, the device that produces alternate position spike between selected ink droplet and unselected ink droplet relies on electrical heating to produce the vapor bubbles of printing ink, and above-mentioned ink vapors bubble is not enough so that the above-mentioned selected printing ink main body of ink droplet from said nozzle separated.

Another preferred version of the present invention is, the device that produces alternate position spike between selected ink droplet and unselected ink droplet drives a PZT (piezoelectric transducer), the latter and above-mentioned printing ink form Mechanical Contact directly or indirectly, and when driving the volume caused an ink cavity that is communicated with printing ink in the printing nozzle and change, this change in volume deficiency so that the above-mentioned selected printing ink main body of ink droplet from said nozzle separate.

Another preferred version of the present invention is that the device of generation alternate position spike makes the electrostatic attraction deficiency so that the above-mentioned selected printing ink main body of ink droplet from said nozzle separated with the printing ink of electrostatic attraction conduction between selected ink droplet and unselected ink droplet.

Another preferred version of the present invention is, the device that separates above-mentioned selected ink droplet from the printing ink main body comprises and arranges in accordance with the following methods printed medium, make selected ink droplet contact above-mentioned printed medium, and make non-selected ink droplet not contact above-mentioned printed medium.

In a preferred version of the present invention, the device that separates above-mentioned selected ink droplet from the printing ink main body comprises and arranges in accordance with the following methods printed medium, make selected ink droplet contact above-mentioned printed medium, and the speed on above-mentioned selected ink droplet infiltration and/or wetting above-mentioned printed medium surface is greater than the speed of overflowing printing ink from printing nozzle.

Another aspect of the present invention is the pressure oscillation of printing ink.

Another aspect of the present invention is, the pressure oscillation frequency of printing ink is the integral multiple of the frequency that sprays in the drops out from nozzles.

Another aspect of the present invention is that the device that separates above-mentioned selected ink droplet from the printing ink main body comprises the printing ink that utilizes static to attract conduction towards recording medium.

Another aspect of the present invention is that the electric field that produces above-mentioned electrostatic attraction is applied on all nozzles substantially equably.

Another aspect of the present invention is that because the alternate position spike between above-mentioned selected ink droplet and the above-mentioned non-selected ink droplet, the difference of the electric attraction that selected ink droplet and non-selected ink droplet are subject to is very large.

Another aspect of the present invention is, the device that separates above-mentioned selected ink droplet from the printing ink main body comprises and utilizes magnetic force to attract printing ink towards recording medium, contains the magnetic rotation material in printing ink.

Another aspect of the present invention is that the magnetic field that produces above-mentioned magnetic attraction is applied on all nozzles substantially equably.

Another aspect of the present invention is that because the alternate position spike between above-mentioned selected ink droplet and the above-mentioned non-selected ink droplet, the difference of the magnetic force that selected ink droplet and non-selected ink droplet are subject to is very large.

In another specific embodiments of the present invention, in selecting, adopt ink droplet sound wave as the power that overlaps, consist of thus method and apparatus of the present invention.

In another preferred embodiment of the present invention, the method and apparatus that the present invention selectes is the distance that changes between printhead of the present invention and the print area, thereby changes the size of the ink droplet of pad-ink.

Brief description of drawings

The schematic block diagram of the simplification of Fig. 1 (a) expression routine printing equipment of the present invention.

The sectional view at one of Fig. 1 (b) expression various nozzles of the present invention top.

The hydrodynamic model that Fig. 2 (a) selects to 2 (f) expression ink droplet.

Fig. 3 (a) is illustrated in the hydrodynamic model that limits element according in the nozzle of one embodiment of the present of invention operation.

Fig. 3 (b) is illustrated in sequenced meniscus position in ink droplet selection and the separation process.

Fig. 3 (c) is illustrated in the temperature on each aspect between the ink droplet selecting period.

The surface tension that Fig. 3 (d) expression measures for various easers and the relation curve of temperature.

Fig. 3 (e) expression is applied on the nozzle heater, thereby produces the electric pulse of temperature curve shown in Fig. 3 (c).

Fig. 4 represents be used to the schematic block diagram that realizes print-head drive circuit of the present invention.

Fig. 5 represents to embody the concrete fabrication yield that is used for A4 pagewidth color print head of feature of the present invention, comprising tolerance being arranged and not having the situation of tolerance.

Fig. 6 represents to adopt the general frame of the print system of one embodiment of the invention.

Fig. 7 represents the sectional view of the print-head nozzle of one embodiment of the invention, uses it for computer simulation in Fig. 8 to 18.

Fig. 8 (a) expression is applied to the power supply subpulse that is used as single heater-driven pulse on the printhead.

Fig. 8 (b) is illustrated in during the ink droplet selection course temperature on each aspect in nozzle.

Fig. 9 is for the meniscus position of ink droplet selection course and the relation curve of time.

Figure 10 is illustrated in the curve of meniscus position and shape during the ink droplet selection course at 5 μ s intervals.

Figure 11 represents the resting position of printing ink meniscus before the ink droplet selection course.

Figure 12 to 17 is illustrated in meniscus position and the hot isopleth in the stages during the ink droplet selection course.

Figure 18 be illustrated in ink droplet select heat pulse begin after flow line chart during 50 μ s.

Figure 19 (a) is to the ink droplet injection cycle of a thermal proximity separating nozzle of 19 (i) expression.

Figure 20 (a) and 20 (b) represent respectively to be applied to sound wave and the space/time diagram on the printing ink, the latter represent to be selected with the quantity of ink of non-selected ink droplet on the nozzle-axis.

The printhead of an embodiment of Figure 21 (a) expression and the sectional view of pressing plate, and Figure 21 (b) is the sectional view of single-nozzle to 21 (d), is used for representing the adjusting of different droplet size.

The detailed description of preferred embodiment

Generally speaking, the present invention has consisted of a kind of print system of throwing in as required, wherein be used for selecting the device of printed dot between selected ink droplet and unselected ink droplet, to produce an alternate position spike, but this alternate position spike deficiency so that ink droplet overcome the surface tension of printing ink and separate from the printing ink main body, and another device is provided therein, has been used for selected ink droplet is separated from the printing ink main body.

Because the ink droplet selecting arrangement separates with the ink droplet separator, so just reduced significantly needed energy when selecting the ink droplet that to print. Only there is the ink droplet selecting arrangement to be driven by the independent signal that offers each nozzle. The ink droplet separator can be a kind of or the state that is applied to simultaneously on all nozzles.

The ink droplet selecting arrangement can be chosen from following listed scheme, but is not limited only to these schemes:

1) reduces the surface tension of pressurized printing ink with Electric heating

2) produce bubble with electrical heating, the volume deficiency of bubble is so that the ink droplet ejection

3) use the piezoelectricity mode, the change deficiency of volume is so that the ink droplet ejection

4) use the electrostatic attraction mode, for each nozzle is equipped with an electrode

The ink droplet separator can be chosen from following listed scheme, but is not limited only to these schemes:

1) near (making recording medium proximity printing head)

2) approach, and the pressure of vibration printing ink

3) electrostatic attraction

4) magnetic field suction

The table of " DOD printing technique index " has represented to throw in as required some desirable features of printing technique. Above-mentioned table has also been listed the certain methods that is better than prior art that some embodiment in the present invention or the inventor's the relevant application adopt.＜DOD printing technique index 〉

Index	The improvement embodiment that surmounts prior art
		High speed operation	Practicality, low price, the printhead of pagewidth has the nozzle more than 10,000. Whole A4 pagewidth printhead can (12 ") silicon wafer be made with the 300mm of standard
High image quality	High-resolution (800dpi is enough for most purposes), six colors are processed, in order to reduce picture noise
		The full color operation	The colour that screens 800dpi by probability carries out half halftone process
The flexibility of printing ink	The operating temperature of printing ink is low, and does not need to form bubble
		Low-power requirements	Because the ink droplet selecting arrangement needn't make ink droplet spray fully, operand power is low
Low price	Whole printhead does not have microwell plate, the rate that manufactures a finished product height, and the existing CMOS manufacturing process through revising is adopted in a small amount of electrical connection
		The high rate that manufactures a finished product	Tolerance is concentrated in the printhead
High reliability	Tolerance is concentrated in the printhead. Eliminate space and section's a word used for translation oil (kogation). Reduce thermal shock.
		A small amount of electrical connection	The CMOS technique of employing standard can concentrate on shift register, control logic and drive circuit on the whole printhead
Use existing VLSI manufacturing process	Because heater-driven power is lower than 1% of hot inkjet heater driving power, can realize the compatibility of CMOS.
		The management of electronization	Can realize the new-type page compressibility of compression in 100: 1, and the deterioration of image and not obvious so just makes the data volume of compression enough low, can print in real time thousands of pages any combination on the disc driver that is stored in low price

In hot ink-jet (TIJ) and piezoelectric inkjet system, the flow velocity of ink droplet is about 10 meters of per second preferably, thereby guarantees that the ink droplet that is selected can overcome ink surface tension and separates from the printing ink main body, and touches recording medium. The efficient of these systems when electric energy is converted to ink droplet kinetic energy is very low. The efficient of TIJ system approximately is 0.02%. This just means that the drive circuit for the TIJ printhead need to switch large electric current. The drive circuit of piezoelectric ink jet printing head need to switch high voltage or drive large capacity load. The total power consumption of pagewidth TIJ printhead also is very large. The A4 full color page TIJ printhead of a 800dpi was printed the electrical power that four look black white images need to consume about 6KW within one second, major part wherein has been converted into useless heat. To remove these heats be very difficult, thereby hindered the manufacturing of low price, high-speed, high-resolution small-sized pagewidth TIJ system.

A key character of the embodiment of the invention is to have reduced significantly as need selecting the required energy of ink droplet of printing with a device. This measure be by the device of selecting ink droplet with guarantee selected ink droplet separated and separate at the device that recording medium forms point from the printing ink main body to realize. Only there is the ink droplet selecting arrangement to be driven by the independent signal that offers each nozzle. And the ink droplet separator can be a kind of or the state that offers simultaneously all nozzles.

The table of " ink droplet selecting arrangement " has represented might be used for according to the present invention several means of selection ink droplet. The ink droplet selecting arrangement only needs to make selected ink droplet to produce enough change in location, makes the ink droplet separator can identify selected ink droplet and unselected ink droplet.＜ink droplet selecting arrangement 〉

Method	Advantage	Restriction
				1. the electricity consumption heat drop hangs down the surface tension of pressurized printing ink	Low-temperature-rise and low ink droplet are selected energy. Can use multiple inks. Simple in structure. The CMOS drive circuit can be assembled on the same substrate.	Need the ink pressure governor motion. Ink surface tension is along with the increase of temperature must be able to descend significantly.
2. the electricity consumption heat drop hangs down ink viscosity, in conjunction with the vibration of ink pressure	Ink droplet selects the energy of usefulness moderate, is applicable to the printing ink of hot melt and oil base. Simple in structure. The CMOS drive circuit can be assembled on the same substrate.	Need the ink pressure oscillating mechanism. The viscosity of printing ink is along with the increase of temperature must significantly descend.
			3. electric heating foaming makes the volume deficiency of bubble so that the ink droplet ejection	Known technology, simple in structure. The bipolar driving circuit can be assembled on the same substrate.	Ink droplet selects energy high, needs water-based inks, has section's a word used for translation oil (kogation), cavity and thermal stress issues
4. the piezoelectricity mode makes the deficient change of volume so that the ink droplet ejection	Can use the printing ink of multiple matrix	Manufacturing cost is high, and integrated circuit technology is complicated, high driving voltage, and complex structure is heavy
			5. an electrode is joined in electrostatic attraction, each nozzle	Simplify the manufacturing of electrode	Injector spacing needs relatively large. Between the adjacent electric field interference is arranged. Need high-voltage driving circuit.

Other ink droplet selecting arrangement also can use.

Preferred ink droplet selection scheme to water-based inks is method 1: " surface tension of the low pressurized printing ink of electricity consumption heat drop ". This ink droplet selecting arrangement has been compared many advantages with other system, this is comprising: low-power operation (approximately be TIJ 1%), compatible with CMOS VLSI chip manufacturing process, low voltage operating (approximately 10V), the high density nozzle, low-temperature operation, and be widely used in various ink formulations. The surface tension of printing ink must reduce along with the increase of temperature.

Preferred ink droplet selection scheme to hot melt or oil-based ink is method 2: " the electricity consumption heat drop hangs down ink viscosity, in conjunction with the vibration of ink pressure ". This ink droplet selecting arrangement is specially adapted to viscosity and significantly descends along with the increase of temperature, but but seldom printing ink of capillary reduction. This phenomenon is obvious especially in having the nonpolar printing ink of relatively high molecular weight. This method is specially adapted to the printing ink of hot melt or oil base.

The table of " ink droplet separator " has provided and has severally separated selected ink droplets from the printing ink main body, and guarantees that selected ink droplet forms the possible method of point at printed medium. The ink droplet separator is identified between selected ink droplet and unselected ink droplet, guarantees that unselected ink droplet can not form a little at printed medium.＜ink droplet separator 〉

Means	Advantage	Restriction
				1. electrostatic attraction	Can print on coarse surface, realize easily	Need high voltage source
2.AC electric field	Can obtain the field intensity higher than static, opereating specification can increase, and ink pressure reduces, and can reduce the gathering of dust	The phase locked high pressure AC power supply that need to spray with ink droplet is difficult to operation when multiple ink droplet phase place
			3. near (printhead approaches still not contact history media)	Can obtain very little point. Power consumption is very low. The precision of drop location is very high.	Need to make the very surface of proximity printing head of printed medium, not be suitable for coarse printed medium, usually need conveying cylinder or belt
4. carry near (making printhead near conveying cylinder or belt)	Can obtain very little point. Power consumption is very low. Precision is high, can print at coarse paper	Because the size restrictions of conveying cylinder or belt conveyor is compact not
			5. approach, and follow the ink pressure vibration	The hot melt printing ink that is used for the ink droplet system of selection of employing reduced viscosity, the possibility of minimizing nozzle blockage can use pigment to replace dyestuff	Require very proximity printing head surface of printed medium, be not suitable for coarse printed medium, need the ink pressure oscillation device
6. magnetic field suction	Can print at rough surface. If use permanent magnet, power are very low	Need uniform high magnetic field intensity, need magnetic ink

Also can use other ink droplet separators.

Preferred ink droplet separation scheme depends on required purposes. In great majority are used, the most suitable employing method 1: " electrostatic attraction ", or method 2: " AC electric field ". The paper that uses smooth finish or film and adopt unusual when high-speed, can using method 3: " approaching ". For at a high speed, high-quality system can using method 4: " carry and approach ". Method 6: " magnetic field suction " is applicable to portable printing system, and the printed medium that this system uses is too coarse, is not suitable for proximity printing, and do not want to adopt electrostatic drop to separate required high voltage. There is not " the best " the ink droplet separator that is applicable to significantly all environment.

Described the further details of various print systems of the present invention in the following Australian patent application specification of submitting to April 12 nineteen ninety-five, these specifications are in this article as with reference to data:

" liquid ink tolerance (LIFT) printing mechanism " (A Liquid ink Fault Tolerant (LIFT) printing mechanism) (application number: PN2308);

" the electric heating ink droplet in LIFT prints is selected " (Electrothermal drop selection in LIFT printing) (application number: PN2309);

" in printing, separates LIFT " (Drop separation in LIFT printing by print media proximity) (application number: PN2310) by the approaching ink droplet that carries out of printed medium;

" in printing near LIFT, adjust ink drop size (Drop size adjustment in Proximity LIFT printing by varying head to media distance) (application number: PN2311) by changing printhead to the distance of media;

" expansion with sound China ink ripple is printed near LIFT " (Augmenting Proximity LIFT printing with acoustic ink waves) (application number: PN2312);

" electrostatic drop in LIFT prints separates " (Electrostatic drop separation in LIFT printing) (application number: PN2313);

" the how synchronous ink drop size in printing near LIFT " (Multiple simulaneous drop sizesin Proximity LIFT printing) (application number: PN2321);

" the certainly cooling operation of thermal excitation printhead " (Self cooling operation in thermally activated print heads) (application number: PN2322); And

" hot sticky reduction LIFT prints " (Thermal Viscosity Reduction LIFT printing) (application number: PN2323).

The rough schematic view that in Fig. 1 (a), has represented the present invention's one routine print system.

Image source 52 can be the panel view data from scanner or computer, or adopts the contour images data of page description language (PDL) form, or other digital image form. This view data is converted to the page-images of pixel graphics by image processing system 53.

Can adopt panel image processor (RIP) for the PDL view data, can adopt pixel image to process to the panel view data. Carry out halftone process by the continuous tone data that image processing apparatus 53 produces, halftone process (Halftoning) is carried out by digital halftone treating apparatus 54. Halftone process bit map view data is stored in the video memory 72. According to the structure of printer and system, video memory can be full page face memory or belt memory. Control circuit for heater 71 is sense data from video memory 72, and provides the upper electric pulse that changes of time to the nozzle heater (103 among Fig. 1 (b)) as printhead 50 parts. These pulses offer suitable nozzle at reasonable time, and selected ink droplet is formed a little by the appropriate location of the data appointment in the video memory 72 on recording medium 51.

Recording medium 51 is moved by paper induction system 65 with respect to printhead 50, and it is be subjected to paper transport control system 66 electronically controlled, and the latter is subjected to the control of a microcontroller 315. Only be schematically to have represented the paper induction system in Fig. 1 (a), many different frame for movements all are possible. If use the printhead of pagewidth, all be moving recording media 51 below static printhead 50 generally. Yet, in the situation of scan-type print system, normally along an axis (inferior scanning direction) mobile print head 50, and along axis (main scanning direction) the mobile print media 51 of quadrature, form the relative motion of panel. Microcontroller 315 can also be controlled page pressure regulator 63 and control circuit for heater 71.

Reduce capillary printing type for adopting, printing ink is installed in the ink storage device 64 that is under the pressure. Under static state (do not have the ink droplet ejection), ink pressure is not enough to overcome the surface tension of printing ink and sprays ink droplet. Under 63 controls of ink pressure adjuster, exert pressure to ink storage device 64, just can obtain constant ink pressure. Otherwise, for larger print system, if make the end face of the printing ink in the holder 64 be in the suitable distance of printhead 50 tops, just can very accurately produce and control the pressure of printing ink. This printing ink liquid level can directly be regulated with unsteady valve (not shown).

Fall low viscous printing type for employing, printing ink is installed in the ink storage device 64 that is under the pressure, and makes ink pressure produce vibration. The device that produces this vibration can be mounted in the piezo-activator in the oil ink passage (not shown).

If the ink droplet separator can correctly be set, selected ink droplet just can form a little at printed medium 51, and unselected ink droplet then still is retained as the part of printing ink main body.

Utilize oil ink passage device 75 the rear surface of distributes ink to printhead 50. Printing ink preferably can be by the seam on the silicon chip that is etched in printhead 50 and/or orifice flow to the front that is provided with nozzle and actuator 64. In the situation that heat is selected, nozzle actuators is electrothermal heater.

In the printer according to some type of the present invention, need the field 74 of an outside to guarantee that the ink droplet of selecting moves from the separation of printing ink main body and towards recording medium 51. Habitual external field 74 is constant electric fields, because the printing ink of conduction is made easily. In this case, can make paper guider or platen 67 with conductive material, and with its electrode as the generation electric field. Another electrode can be that printhead 50 is own. Another embodiment adopts the means of proximity printing media to identify selected ink droplet and unselected ink droplet.

Because ink droplet is very little, the gravity that acts on the ink droplet is very little; Approximately be capillary 10^-4, therefore can ignore gravity as a rule. So just allow printhead 50 to align in any direction with respect to Local Gravity Field with recording medium 51. This point is an important requirement of portable printer.

Fig. 1 (b) is the cross section enlarged drawing with a micro nozzle tip of the embodiment of the invention of improved CMOS technique manufacturing. Nozzle is etched on a substrate 101, and substrate can be silicon chip, glass, metal or other suitable materials. If use the substrate of non-semiconductor material, can deposit a kind of semi-conducting material (for example non-crystalline silicon) at substrate, and can in the surface of semiconductor layer, form integrated driving transistors and data allocation circuit. Monocrystalline silicon (SCS) substrate has following several advantages:

1) in SCS, can make high performance driving transistors and other circuit;

2) adopt the VLSI process equipment of standard can under existing convenience (fabs), make printhead;

3) SCS has very high mechanical strength and rigidity; And

4) SCS has high thermal conductivity.

In this example, nozzle is columnar, and heater 103 forms a ring. The tip 104 of nozzle is that the silicon dioxide layer 102 with deposition forms during making the CMOS drive circuit. The tip silicon nitride passivation of nozzle. The outstanding contact point of nozzle tip control pressurized printing ink 100 on print head surface. Print head surface or hydrophobic diffusion occurs once in a while in case be in the procephalic printing ink of printing.

The nozzle of many other structures also is feasible, and can change the material of shape, size and use in the embodiment of nozzle of the present invention. The nozzle that is etched into monolithic with substrate when forming heater and drive circuit has an advantage, and that is exactly not need microwell plate. When making and assemble, saved microwell plate cost is reduced significantly. The method that is used at present the omission microwell plate comprises use ' eddy current ' actuator, transferred the patent US4 of Xerox in 1986 such as people such as Domoto, 580, in No. 158 and the people such as Miller transferred the patent US5 of Hewlett-Packard in 1994, actuator described in 371, No. 527. Yet these actuators are that complexity is difficult to again make. The present invention packs microwell plate in the actuator substrate into.

This nozzle can be used for adopting various technical points from the printhead of ink droplet.

The working method that electrostatic drop separates

As an example, in Fig. 2, represented the working method of utilizing heating to reduce surface tension and adopt static to separate ink droplet.

Fig. 2 has represented the Inc. with Fluid Dynamics, energy transfer and fluid dynamic simulation result that the fluid dynamic simulation software kit FIDAP of the commercialization that of Illinois USA provides carries out. This simulation is to select nozzle to realize that environment temperature is 30 ℃ with the heating ink droplet of diameter 8 μ m. The gross energy that offers heater is 276nJ, applies respectively 69 pulses that respectively account for 4nJ. Ink pressure is than the high 10KPa of ambient atmosphere pressure, and ink viscosity is 1.84cPs in the time of 30 ℃. Printing ink is water base, and comprises 0.1% hexadecanoic acid colloidal sol, is used for promoting capillary decline along with the increase of temperature. Represented in the drawings the nozzle tip cross section from the central shaft of nozzle to 40 μ m of radius distance. Adopt the material of various density, thermal capacity and thermal conductivity to simulate in the various materials of flow nozzle, comprise silicon chip, silicon nitride, noncrystal silica, crystalline silica and water base printing ink. The time interval of simulation is 0.1 μ s.

Fig. 2 (a) has represented to start heater inactive state before. Guarantee at ambient temperature to make ink pressure to add that outside electrostatic field is not enough to overcome the surface tension of printing ink, thereby produce a kind of balance, printing ink under static state can not overflowed from nozzle. Under static state, the meniscus of printing ink can not given prominence to from the surface of printhead significantly, and therefore, electrostatic field can not concentrate on the meniscus significantly.

Fig. 2 (b) be illustrated in the heater driving pulse start after 5 ℃ of hot isopleth during the 5 μ s of interval. When heater was subject to encouraging, the printing ink that contacts with nozzle tip was heated rapidly. The heated portion that capillary decline makes meniscus extends rapidly with respect to the meniscus of cold oil China ink. The convection current that causes is thus transferred to rapidly on the whole Free Surface of printing ink at nozzle tip place heat. Heat should be assigned on the whole ink pellet surface, rather than only concentrate on printing ink that heater contacts in. This is because stoped the movement of the printing ink that directly contacts with heater with respect to the viscosity resistance of solid heater.

5 ℃ of hot isopleth when Fig. 2 (c) has represented after the heater driving pulse starts interval 10 μ s. The increase of temperature reduces surface tension, has upset equilibrium of forces. Along with whole meniscus is heated, printing ink begins to flow.

Fig. 2 (d) be illustrated in the heater driving pulse start after 5 ℃ of hot isopleth during the 20 μ s of interval. The pressure of printing ink has made printing ink flow to a new meniscus position, and meniscus is outstanding from printhead.

Fig. 2 (e) be illustrated in the heater driving pulse start after 5 ℃ of hot isopleth during the 30 μ s of interval since the duration of heater pulse be 24 μ s, this moment also be after heater pulse finishes 6 μ s constantly. Because the conduction of oxide layer, nozzle tip has cooled off rapidly, and is transmitted to mobile printing ink. Printing ink has played effectively " water-cooled " effect to nozzle tip. Electrostatic attraction makes ink droplet begin to accelerate towards recording medium. If heater pulse obviously shortens (for example less than 16 μ s), printing ink just can not accelerate towards recording medium, but in the nozzle of can retracting.

5 ℃ of hot isopleth after Fig. 2 (f) expression heater pulse finishes during the 26 μ s of interval. The temperature at nozzle tip place exceeds 5 ℃ of less thaies than environment temperature at this moment. Nozzle tip surface tension is on every side increased. When the speed that is drawn out of from nozzle when printing ink has surpassed the speed that is subjected to viscous force restriction when printing ink is flowed through nozzle, the printing ink in the nozzle tip zone will ' shrink ', and selected ink droplet will separate from the printing ink main body. Selected ink droplet externally flows on the recording medium under the effect of electrostatic field subsequently. And the printing ink meniscus at nozzle tip place will return to its resting position at this moment. Wait for that next heat pulse removes to select next ink droplet. Each heat pulse is selected and is separated an ink droplet, and forms a point in recording medium. Because heat pulse just can realize the inkjet printer operation of throwing in as required by circuit control.

Fig. 3 (a) according to 5 μ s time interval from the ink droplet selection cycle that the heater starting pulse begins the order meniscus position.

Fig. 3 (b) is meniscus position with respect to the curve of time, has represented the movement of meniscus central point. 10 μ s enter simulation after heater pulse begins.

Fig. 3 (c) is illustrated in the nozzle temperature on each aspect with respect to the relation curve of time. The longitudinal axis of curve represents temperature, and unit is 100 ℃. The transverse axis of curve represents the time, and unit is 10 μ s. Temperature curve shown in Fig. 3 (b) is to utilize FIDAP to calculate according to the time interval of 0.1 μ s. Local ambient temperature is 30 ℃. Represented in the drawings the thermograph on three points.

A-nozzle tip: represented passivation layer, the thermograph between printing ink and the air in the contact circulation.

B-meniscus mid point: this point is the middle circle of printing ink meniscus between nozzle tip and the meniscus center.

The C-chip surface: this point is on the print head surface apart from nozzle center 20 μ s places. Temperature has only risen the several years. This show function circuit can be very near nozzle, and can not affect owing to the rising of temperature performance or reduce the life-span.

Fig. 3 (e) expression offers the power of heater. Best operation requirements temperature sharply rises in the starting point of heater pulse, at impulse duration temperature is maintained slightly to be lower than the printing ink boiling point, and when end-of-pulsing temperature is descended rapidly. Need to change the average energy that offers heater at whole impulse duration for this reason. In this case, be that the energy that pulse frequency modulated by 0.1 μ s slave pulses obtains each slave pulses of this change is 4nJ. The peak power that offers heater is 40mW, and the mean power during heater pulse is whole is 11.5mW. The slave pulses frequency of this moment is 5MHz. This point is easy to change, and can not affect significantly the operation of printhead. Higher slave pulses frequency can realize more accurate control in the process that power is provided to heater. Suitable slave pulses frequency is 13.5MHz, because this frequency also is fit to reduce to greatest extent the impact of Radio frequency interference (RFI).

Surface tension has the printing ink of negative temperature coefficient

The surface tension of printing ink is increased along with temperature and the requirement that reduces is not a main restriction, because most of pure liquid and many mixtures all have this character. For liquid arbitrarily, there is not the exact relationship formula of surface tension and temperature. Yet the following empirical equation of being derived by Ramsay and Shields can be fit to many liquid:

γ T wherein is the surface tension of temperature when being T, and k is a constant, and Tc is the critical-temperature of liquid, and M is the molecular weight of liquid, and x is association (association) degree of liquid, and ρ is the density of liquid. This formula shows that the surface tension of most liquid can drop to zero when temperature reaches the critical-temperature of liquid. Under atmospheric pressure, the critical-temperature of most liquid all is higher than its boiling point significantly, therefore, in order to obtain the larger variation of ink surface tension with less variations in temperature near the injection temperation of reality, needs to add surfactant.

The selection of surfactant is very important. For example, the water-based inks that is used for thermal ink jet printers usually comprises for reducing surface tension and impels its rapidly dry isopropyl alcohol (2-propyl alcohol). The boiling point of isopropyl alcohol is 82.4 ℃, is lower than the boiling point of water. Along with the increase of temperature, alcohol is vaporized quickly than water, the concentration of alcohol is reduced, and surface tension is increased. Surfactant such as 1-ethanol (b.p.158 ℃) can be used for offseting this effect, and obtains with temperature a little surface tension of decline. Yet, in order to increase opereating specification as far as possible, need to make the surface tension decline relatively large along with temperature has. Preferably make the surface tension 20mN/m that in 30 ℃ temperature range, can descend, in order to obtain large opereating specification, in order to satisfy the action need of printhead of the present invention, minimumly will adopt 10mN/m.

Printing ink with large-Δ γ T

Can come to make surface tension obtain larger negative variation along with the increase of temperature with several method. Two kinds of these class methods are as follows:

1) printing ink can comprise the surfactant colloidal sol of low concentration, and this colloidal sol is solid at ambient temperature, but dissolves under a threshold temperature. Granularity should be less than 1000 . The suitable molten point of the surfactant of water-based inks is between 50 ℃ to 90 ℃, preferably is between 60 ℃ to 80 ℃.

2) printing ink can comprise a kind of micro emulsion of oil/water, and its phase inversion temperature (PIT) is higher than high ambient temperature, but is lower than the boiling point of printing ink. For stable, the PIT of micro emulsion preferably be on the highest nonoperating temperature that printing ink can run into more than 20 ℃. Suitable PIT value approximately is 80 ℃.

The printing ink that contains surfactant colloidal sol

In the printing ink of preparation, the granule colloidal sol of surfactant is dissolved in the operating temperature range of appointment. The example of this surfactant comprises the carboxylic acid with 14 to 30 carbon atoms, for example:

Title	General formula	m.p.	Different name
				Tetradecanoic acid	CH 3(CH 2) 12COOH	58℃	Myristic acid
Hexadecanoic acid	CH 3(CH 2) 14COOH	63℃	Palmitic acid
				Octadecanoid acid	CH 3(CH 2) 15COOH	71℃	Stearic acid
Arachic acid	CH 3(CH 2) 16COOH	77℃	Arachidic acid
				Behenic acid	CH 3(CH 2) 20 COOH	80℃	Behenic acid

Owing to have the molten point of colloidal sol of small particle size usually a shade below the material of bulky grain degree, preferably select a kind of molten carboxylic acid slightly higher than required ink droplet selection temperature. A kind of good example is arachic acid.

Can be with having bought at a low price the highly purified carboxylic acid of this class. Therefore the amount of needed surfactant seldom, is added activating agent cost is obviously increased in different name. The mixed carboxylic acid of the length slight change of chain can be used for making molten point to be distributed in certain temperature range. The price of this mixture is usually low than pure acid.

The selection of surfactant not necessarily is limited in simple without branch's carboxylic acid. Also can use with side chain or phenyl or the surfactant of other hydrophobic ingredients. And also not necessarily to use carboxylic acid. The composition of many high degree of polarization can be used for the water-wet side of surfactant. Polarization end should be able to be at the water intermediate ion, thereby makes the surface charging of surfactant granules, helps like this to disperse and prevent flocculation. If the use carboxylic acid can be realized by adding basic species such as NaOH or potassium hydroxide.

Preparation with the printing ink of surfactant colloidal sol

The surfactant colloidal sol that can prepare separately high concentration, and add in the printing ink by needed concentration.

The concrete grammar of making surfactant colloidal sol is as follows:

1) in the environment of anoxic, in pure water, adds carboxylic acid.

2) mixture is heated to more than the molten point of carboxylic acid. Can make the water boiling.

3) mixture is carried out supersonic oscillations, until the typical size of carboxylic acid ink droplet is between 100 to 1000 .

4) make the mixture cooling.

5) above mixture, analyse larger particle.

6) add for example alkaline matter of NaOH, make the carboxylic acid molecules ionization on the particle surface. Suitable pH value is 8. This step not necessarily still helps to make Stability of Sols.

7) colloidal sol is done centrifugal treating. Because the proportion of carboxylic acid is lower than water, little particle is concentrated in the outside of centrifuge, and large particle is in the center.

8) filter colloidal sol with millipore filter, remove any particle greater than 5000 .

9) in the printing ink of preparation, add surfactant colloidal sol. Colloidal sol only needs very rare concentration.

The printing ink of preparation can also comprise dyestuff or pigment, bactericidal additive, when using electrostatic drop to separate for increasing the additive of printing ink electric conductivity, wetting agent, and other additives that need.

Usually do not need to put the foam agent, because in the ink droplet course of injection, can not form bubble.

Cationic surfactant colloidal sol

The printing ink made from cationic surfactant colloidal sol is not suitable for using with cationic dyestuff or pigment usually. This is because cationic dyestuff or pigment may form precipitation or flocculation with cationic surfactant. In order to use cationic pigment or dyestuff, need a kind of colloidal sol of cationic surfactant. Alkylamine family is applicable to this purposes.

Various suitable alkylamine families are as shown in the table:

Title	General formula	Different name
			Hexadecylamine	CH 3(CH 2) 14CH 2NH 2	Palmitamide
Octadecylamine	CH 3(CH 2) 16CH 2NH 2	Stearylamine
			Eicosyl amine	CH 3(CH 2) 18CH 2NH 2	Peanut amine
Docosyl amine	CH 3(CH 2) 20CH 2NH 2	Shan Yu amine

The method for preparing cationic surfactant colloidal sol is basic identical with the method that prepare anion surfactant colloidal sol, just with acid substitution alkali, in order to be used for regulating the balance of pH and the electric charge on the increase surfactant granules. When using HCI, suitable pH value is 6.

The printing ink of micro emulsion matrix

Just the rapid another kind of means that descend are the printing ink that adopts take micro emulsion as matrix to surface tension at a certain temperature threshold place. The phase inversion temperature of selected micro emulsion (PIT) is near the required injection threshold temperature. Below PIT, micro emulsion is the oil (O/W) in the water, and more than PIT, micro emulsion then is the water (W/O) in the oil. When low temperature, the surfactant that consists of micro emulsion forms the deep camber surface that encases oil, and when temperature during apparently higher than PIT, it is surperficial that surfactant then forms the deep camber that encases water. At the temperature place near PIT, micro emulsion forms presses water and oily continuous " cavernous body " that topological structure connects.

Capillary this decline phenomenon has two kinds of mechanism. Near PIT, surfactant forms the very low surface of curvature, and its curvature is well below the curvature of oil emulsion. So just reduced the surface tension of water. More than phase inversion temperature, micro emulsion has become W/O from O/W, so the interface of printing ink/air has become oil/air from water/air. And the interface of oil/air has lower surface tension.

There are many possible methods to can be used for preparing the printing ink of micro emulsion matrix.

For quick ink-jet, preferably select low viscous oil.

In many examples, water is a kind of suitable polarization solvent. Yet, may need different polarization solvents in some occasion. In these cases, should select to have large capillary polarization solvent, surface tension is sharply descended.

The selection result of surfactant can make phase inversion temperature be within the required scope. For example, can use poly-(oxygen ethene) alkyl phenyl ether (ethoxylated alkyl phenol, general formula is:

C _nH _2n＋1C ₄H ₆(CH ₂CH ₂O)～ _mOH) family. If increase m, just can improve the hydrophily of surfactant, increase n and also can improve hydrophily. Value is approximately 10, and the desired value of n is about 8.

Can prepare the goods of low price with the polymer of the oxirane of various molecule ratios and alkyl phenol, and the accurate quantity of oxyethylene group changes near selected mean value. Goods on these markets just can be satisfied the demand, and do not need to possess the pure surfactant of height of specific quantity oxyethylene group.

The general formula of this surfactant is C₈H ₁₇C ₄H ₆(CH ₂CH ₂O) _nOH (average n=10).

Synonyms comprises Octoxynol-10, PEG-10 octyl phenyl ether and POE (10) octyl phenyl ether.

HLB is 13.6, and molten point is 7 ℃, and cloud point is 65 ℃.

The goods of this surfactant on market have following brand. In following table, listed the title of supplier and commodity:

Trade name	Supplier
		Akyporox OP100	Chem-Y GmbH
Alkasurf OP-10	Rhone-Poulenc Sufactants and Specialties
		Dehydrophen POP10	Pulcra SA
Hyonic OP-10	Henkel Crop.
		Iconol OP-10	BASF Crop.
Igepal O	Rhone-Poulenc France
		Macol OP-10	PPG Industries
Malorphen 810	Huls AG
		Nikk0l OP-10	Nikko Chem.Co.Ltd.
Renex 750	ICI Americas Inc.
		Rexol 45/10	Hart Chemical Ltd.
Synperonic OP 10	ICI PLC
		Teric X10	ICI Australia

These products can be with having bought (each pound is less than one dollar) at a low price in a large number, and therefore, when preparation contained the micro emulsion printing ink of 5% surfactant concentration, each rises only need to be less than 10 cents.

In following table, comprised other applicable ethoxylated alkyl phenol:

Popular name	General formula	HLB	Cloud point
				Nonoxynol-9	C 9H 19C 4H 6(CH 2CH 2O)～ 9 OH	13	54℃
Nonoxynol-10	C 9H 19C 4H 6(CH 2CH 2O)～ 10OH	13.2	62℃
				Nonoxynol-11	C 9H 19C 4H 6(CH 2CH 2O)～ 11OH	13.8	72℃
Nonoxynol-12	C 9H 19C 4H 6(CH 2CH 2O)～ 12OH	14.5	81℃
				Octoxynol-9	C 8H 17C 4H 6(CH 2CH 2O)～ 9OH	12.1	61℃
Octoxynol-10	C 8H 17C 4H 6(CH 2CH 2O)～ 10OH	13.6	65℃
				Octoxynol-12	C 8H 17C 4H 6(CH 2CH 2O)～ 12OH	14.6	88℃
Dodoxynol-10	C 12H 25C 4H 6(CH 2CH 2O)～ 10OH	12.6	42℃
				Dodoxynol-11	C 12H 25C 4H 6(CH 2CH 2O)～ 11OH	13.5	56℃
Dodoxynol-14	C 12H 25C 4H 6(CH 2CH 2O)～ 14OH	14.5	87℃

Except capillary control, the printing ink of micro emulsion matrix also has other advantages:

1) micro emulsion is stable at thermodynamics, and can not separate. Therefore, the time of storage can be very long. This point is particularly useful for office and portable printer that those just use once in a while.

2) micro emulsion can be formed naturally the ink droplet of specific size, and does not need to stir thoroughly, and centrifugal or filtration just can guarantee to make the size of oil emulsion ink droplet to be in specific scope.

Therefore 3) contained oil mass can be very high in printing ink, can use oil-soluble or water soluble or dissolve in the two dyestuff. Also can use the dyestuff of mixing, a kind of water soluble, another kind of oil-soluble so just can obtain specific color.

4) can stop the flocculation of oily miscible pigment, because it is to be rolled in the small ink droplet of oil.

5) use micro emulsion can reduce the color of different pigment in the lip-deep mixing of printed medium.

6) viscosity of micro emulsion is very low.

7) can reduce or do not use wetting agent.

Dyestuff and pigment in the micro emulsion matrix printing ink

The mixture of oil-containing can have very high oil content-up to 40%-and still can consist of the micro emulsion of O/W in the water. So just can add a lot of dyestuffs or pigment.

Can use the mixture of dyestuff and pigment. The ink mixture of a routine micro emulsion matrix that comprises dyestuff and pigment is as described below:

1) 70% water

2) 5% the water stain

3) 5% surfactant

4) 10% oil

5) 10% oily miscible pigment

Nine kinds of operational basic combinations that belong to oil phase and the water colouring agent of micro emulsion have been represented in the following table.

Combination	The colouring agent of water	The colouring agent of oil phase
			1	Nothing	The miscible pigment of oil
2	Nothing	Oil-soluble dyes
			3	The water stain	Nothing
4	The water stain	The miscible pigment of oil
			5	The water stain	Oil-soluble dyes
6	The pigment that is dispersed in water	Nothing
			7	The pigment that is dispersed in water	The miscible pigment of oil
8	The pigment that is dispersed in water	Oil-soluble dyes
			9	Nothing	Nothing

Do not have colouring agent in the 9th kind of combination, it can be used for the front cover of print transpatent, UV printing ink, and the signal portion of glazing selectively.

Because many dyestuffs all are amphiphilics, also can dissolve a large amount of dyestuffs in the oil-water boundary layer, because the surface area of this one deck is very large.

Also can use the multiple dyestuff or the pigment that are in various liquid phases, and obtain the dyestuff of various liquid phases and the mixture of pigment.

When using multiple dyestuff and pigment, the absorption spectrum of synthetic ink is the weighted average of the absorption spectrum of used different colorant. Can produce like this two kinds of problems:

1) because the absorption peak of two kinds of colouring agents is averaged, absorption spectrum can trend towards broadening. Can cause like this color ' muddiness ' trend. In order to obtain color true to nature, need to carry out careful selection according to the absorption spectrum of dyestuff and pigment, and be not only the color of selecting human eye to see.

2) color of printing ink may be different on different substrates. If used dyestuff and pigment in combination, if print at the larger paper of absorbability, the color of dyestuff role in the ink colors of printing is less because dyestuff can be inhaled in the paper, pigment then can ' lid ' on paper. This is a kind of advantage in some occasion.

The Krafft point is in the surfactant within the ink droplet selection temperature range

For Ionized surfactant, a temperature (Krafft point) is arranged, below the temperature, its solubility is very low at this, and does not basically comprise colloidal ion in the solution. More than the Krafft temperature, might form colloidal ion, and the solubility of surfactant can increase rapidly. If critical colloidal ion concentration (CMC) has surpassed the solubility of surfactant at a certain temperature, just can be on the point of solubility maximum rather than the CMC point obtain minimum surface tension. The effect of surfactant when the Krafft point is following is normally very low.

This phenomenon can be used for making surface tension along with the increase of temperature further reduces. At ambient temperature, some surfactant in the solution. When nozzle heater was opened, temperature rose, and more surfactant will enter in the solution, and surface tension is reduced.

When the option table surface-active agent, its Krafft point should be near the upper limit of the temperature range of printing ink heating. So just can make concentration and the ink droplet of environment temperature lower surface activating agent in solution select to obtain between the concentration of temperature lower surface activating agent in solution maximum surplus.

The concentration of surfactant should approximate greatly CMC on the Kraft point. Adopt this method, when temperature rises, can farthest reduce surface tension, and make at ambient temperature capillary decline minimum.

Following table has represented that several Krafft points are in the surfactant of the commercialization of ideal range.

General formula	The Krafft point
		C 16H 33SO 3 -Na +	57℃
C 18H 37SO 3 -Na +	70℃
		C 16H 33SO 4 -Na +	45℃
Na +O 4S(CH 2) 16SO 4 -Na +	44.9℃
		K +O 4S(CH 2) 16SO 4 -K +	55℃
C 16H 33CH(CH 3)C 4H 6SO 3 -Na +	60.8℃

Cloud point is in the surfactant within the ink droplet selection temperature range

Adopt the non-ionic surface active agent of polyoxyethylene (POE) chain can be used for making such printing ink, its surface tension reduces along with the increase of temperature. When low temperature, the POE chain is hydrophilic, and surfactant is retained in the solution. When temperature rose, the steeping in water for reconstitution life of constructing around the molecule of POE part was broken, and the POE part has just become hydrophobic. Water can further resist surfactant when high temperature, so that the surfactant concentration on the air/oil China ink interface increases, so just reduced surface tension. It is relevant with the cloud point of surfactant to make the POE of non-ionic surface active agent partly become hydrophilic actual temp. The POE chain itself is not specially suitable, because its cloud point is generally more than 100 ℃.

Polyoxypropylene (POP) can be used to be combined into the POE/POP block copolymer with POE, thereby reduces the cloud point of POE chain, and can not produce very strong hydrophily when low temperature.

Have the POE/POP block copolymer of symmetry of two kinds of primary structures available, they are:

1) have the POE section in the end of molecule, and the surfactant that has the POP section in the centre, for example surfactant of poloxamer level (general designation CAS 9003-11-6).

2) have the POP section in the end of molecule, and the surfactant that has the POE section in the centre, for example surfactant of meroxapol level (also being to be called CAS 9003-11-6).

Listed various poloxamer and the meroxapol that sell in market in following table, they at room temperature have higher surface tension, and its cloud point is more than 40 ℃ and below 100 ℃.

Popular name	The BASF trade name	General formula	Surface tension (mN/m)	Cloud point
					Meroxa pol     105	Pluronic   10R5	HO(CHCH 3CH 2O)～ 7(CH 2CH 2O) ～ 22-(CHCH 3CH 2O)～ 7OH	50.9	69℃
Meroxa pol     108	Pluronic     10R8	HO(CHCH 3CH 2O)～ 7(CH 2CH 2O) ～99-(CHCH 3CH 2O)～ 7OH	54.1	99℃
					Meroxa pol     178	Pluronic     17R8	HO(CHCH 3CH 2O)～ 12(CH 2CH 2O) ～ 136-(CHCH 3CH 2O)～ 12OH	47.3	81℃
Meroxa pol     258	Pluronic   25R8	HO(CHCH 3CH 2O)～ 18(CH 2CH 2O) ～ 163-(CHCH 3CH 2O)～ 18OH	46.1	80℃
					Poloxamer     105	Pluronic     L35	HO(CH 2CH 2O)～ 11(CHCH 3CH 2O) ～ 16-(CH 2CH 2O)～ 11OH	48.8	77℃
Poloxamer     124	Pluronic     L44	HO(CH 2CH 2O)～ 11(CHCH 3CH 2O) ～ 21-(CH 2CH 2O)～ 11OH	45.3	65℃

Adopt known technology also can be easy to synthesize other various poloxamer and meroxapol. Desirable characteristic is to make surface tension at room temperature high as best one can, and cloud point is between 40 ℃ to 100 ℃, preferably 60 ℃ to 80 ℃.

At Meroxapol[HO (CHCH₃CH ₂O) _x(CH ₂CH ₂O) _y(CHCH ₃CH ₂O) ₂OH] in the product, the suitable mean value of x and z is 4, and the mean value of y is 15.

If increase the electric conductivity of printing ink with salt, just need to consider the impact of the cloud point of this salt Surfactant.

If break the structure (for example 1) of water with ion, just can improve the cloud point of surfactant, because can make so more hydrone and POE oxygen orphan to consisting of hydrogen bond. Utilize to form the water structure ion (for example Cl～, OH～) can reduce the cloud point of POE surfactant, this is less because can consist of the hydrone of hydrogen bond. Bromide ion affect less. By the length that changes POE in the block copolymer surfactant and POP chain can make ink composition in the temperature range of appointment ' change ', and can by change the salt that adds (be CI～to Br～to I～) selection increase electric conductivity. NaCl is being best selection aspect the increase electric conductivity, because it is very cheap and nontoxic. NaCl can make the cloud point of non-ionic surface active agent reduce slightly.

Hot melt printing ink

Printing ink at room temperature not necessarily must be liquid. If printhead and ink storage device are heated on the molten point of printing ink, just can use solid ' hot melt ' printing ink. Hot melt printing ink must be made according to prescription, and the surface tension of dissolving printing ink is reduced along with temperature. The typical reduction amplitude of the goods of many employing waxes and other materials approximately is 2mN/m. Yet when relying on the reduction surface tension rather than reducing viscosity, in order to obtain desirable operation tolerance limit, it should be about 20mN/m that desirable surface tension reduces amplitude.

For hot melt printing ink, static temperature and ink droplet select the temperature difference that the temperature difference between the temperature can be than for water-based inks the time large, because water-based inks is subject to the restriction of the boiling point of water.

Printing ink must be liquid under static temperature. This static temperature should be higher than being printed the high ambient temperature that the page may run into. Simultaneously, static temperature should be low as far as possible, in order to reduce power required when adding thermal printer head, and provides maximum tolerance limit between static temperature and ink droplet injection temperation. The most general static temperature is between 60 ℃ to 90 ℃, although also can adopt other temperature range. The most general ink droplet injection temperation is between 160 ℃ to 200 ℃.

There is following several method to realize and to promote surface tension to reduce along with the rising of temperature.

1) fine granular of dissemination surface activating agent, its molten point is higher than static temperature significantly, but is lower than significantly the ink droplet injection temperation, can under liquid-phase condition it be added hot melt printing ink.

2) a kind of polarization/non-polarised micro emulsion, the molten point that its PIT cans be compared to polarization and non-polarized compound most is high at least 20 ℃.

For surface tension is sharply reduced along with temperature, the carrier of hot melt printing ink should have relatively large surface tension (more than 30mN/m) under static temperature. Typically use for example alkane of wax. Suitable material has very strong intermolecular attraction usually, and this gravitation can be obtained by many hydrogen bonds, polyalcohol for example, and for example, the molten point of Hexanetetrol is 88 ℃.

The surface tension of various solution reduces

Fig. 3 (d) is illustrated in comprise following additive various and contains in the aquatic product temperature effect for stalagmometry:

1) 0.1% octadecanoid acid colloidal sol

2) 0.1% hexadecanoic acid colloidal sol

3) 0.1% Pluronic10R5 (trade mark of BASF) solution

4) O.1% Pluronic L35 (trade mark of BASF) solution

5) 0.1% Pluronic L44 (trade mark of BASF) solution

Illustrated to be fit to the printing ink that print system of the present invention is used in following Australian patent specification, these specifications can be used as reference herein:

" based on the ink combination of microemulsion " (Ink composition based on a microemulsion) (application number: PN5223, submit September 6 nineteen ninety-five);

" ink combination that comprises surfactant " (Ink composition containing surfactant sol) (application number: PN5224, submit September 6 nineteen ninety-five);

" near the ink combination of the DOD printer that has Krafft to order selecting temperature at ink droplet " (Ink composition for DOD printers with Krafft point near the drop selection temperture sol) (application number: PN6240, submit October 30 nineteen ninety-five); And

" based on the dyestuff in the microemulsion of printing ink and pigment " (Dye and pigment in a microemulsion based ink) (application number: PN6241, the nineteen ninety-five 1O month 30 submitted).

Low viscous operation falls in employing

As second example, in following embodiment, reduce viscosity and employing separates ink droplet near mode by heating in combination with hot melt printing ink. Before printer operation, in holder 64, solid ink is dissolved. Printing ink leads to printhead by oil ink passage 75 from holder, and printhead 50 maintained makes printing ink 100 be in liquid state, but the but temperature of relatively high (for example approximately 100cP) of viscosity. Surface tension by printing ink is limited in printing ink 100 within the nozzle. Printing ink 100 is made by prescription, and its viscosity is reduced along with the rising of temperature. Ink pressure is vibrated at certain frequency, and this frequency is the integral multiple of the frequency of spraying in the drops out from nozzles. The pressure oscillation of printing ink is so that be in the printing ink meniscus of nozzle tip and vibrate, but because the viscosity of printing ink is very high, this vibration is very little. Under normal running temperature, the underswing of this vibration is so that the ink droplet separation. When heater 103 was activated, the printing ink that consists of selected ink droplet was heated, and its reduced viscosity is to certain value, and this value is preferably less than 5cP. The reduction of viscosity is moved further the printing ink meniscus during the high pressure section of ink pressure circulation. Recording medium 51 is arranged on the position of fully close printhead 50, makes selected ink droplet touch recording medium 51, but enough far away again, makes unselected ink droplet can not run into recording medium 51. When touching recording medium 51, selected part ink droplet will solidify, and is adsorbed on the recording medium. Along with the decline of ink pressure, printing ink begins to get back in the nozzle. The main body of printing ink is separated with printing ink on being set in recording medium. Then, return to again by a small margin vibration at the meniscus of the printing ink 100 of nozzle tip. Be dispersed into along with remaining heat on the printing ink and printhead of bulk, the viscosity rise of printing ink is to its static level. Each thermal pulse is selected and is separated an ink droplet, and forms a point in recording medium 51. Because thermal pulse just can realize the ink ejection operation mode of throwing in as required by circuit control.

The manufacturing of printhead

Described the manufacture method of monolithic print head of the present invention in the following Australian patent specification of submitting April 12 nineteen ninety-five, these specifications can be used as reference herein:

" monolithic LIFT printhead " (A monolithic LIFT printing head) (application number: PN2301);

" manufacture method of monolithic LIFT printhead " (A manufacturing process for monolithic LIFT printing head) (application number: PN2302);

" the auto-collimation design of LIFT printhead " (A self-aligned header design for LIFT print heads) (application number: PN2303);

" integrated four look LIFT printheads " (Integrated four color LIFT print heads) (application number: PN2304);

" reduction of the power requirement in monolithic print head " (Power requirement reduction in monolithic LIFT printing heads) (application number: PN2305);

" manufacture method of employing wet corrosion LIFT printhead " (A manufacturing process for monolithic LIFT print heads using anisotropic wet etching) (application number: PN2306);

" nozzle location in monolithic DOD printhead " (Nozzle placement in monolithic drop-on-demend print heads) (application number: PN2307);

" the heating head structure of monolithic print head " (Heater structure for monolithic LIFT print heads) (application number: PN2346);

" connection of monolithic LIFT printhead power supply " (Power supply connection for monolithic LIFT print heads) (application number: PN2347);

" near the outside connection of LIFT printhead " (External connection for Proximity LIFT print heads) (application number: PN2348); And

" " the auto-collimation manufacture method of monolithic LIFT printhead " (A self-aligned manufacturing process for monolithic LIFT print heads) (application number: PN2349); And

" the CMOS compatible making method of LIFT printhead " (CMOS process compatible fabrication of LIFT print heads) (application number: PN5222, submit September 6 nineteen ninety-five).

" manufacture method with LIFT printhead of nozzle edge heater " (A manufacturing process for LIFT print heads with nozzle rim heater) (application number: PN6238, submit October 30 nineteen ninety-five);

" module LIFT printhead " (A modular LIFT print head) (application number: PN6237, on October 30th, 1995 submitted);

" increase the method for printing nozzle packed density " (Mothod of increasing packing density of printing nozzle) (application number: PN6236, submit October 30 nineteen ninety-five); And

" nozzle that reduces electrostatic interaction between the isochronous printing ink droplet scatters " (Nozzle dispersion for reduced electrostatic interaction between simultaneously printed droplets)

(application number: PN6239, submit October 30 nineteen ninety-five).

The control of printhead

Described the device of the heter temperature that is used in the present invention providing page-images data and control printhead in the following Australian patent specification of submitting April 12 nineteen ninety-five, these specifications can be used as reference herein:

" integrated drive electronics in the LIFT printhead " (Integrated dive circuitry in LIFT print heads) (application number: PN2295);

" the nozzle cleaning process that is used for liquid ink capacity (LIFT) printing " (A nozzle clearing procedure for Liquid Ink Fault Tolerant (LIFT) printing) (application number: PN2294);

" heater power that is used for LIFT print system temperature compensates " (Heater power compensation for temperature in LIFT printing systems) (application number: PN2314);

" heater power that is used for LIFT print system thermo-lag compensates " (Heater power compensation for thermal lag in LIFT printing systems) (application number: PN2315);

" heater power that is used for LIFT print system print density compensates " (Heater power compensation for print density in LIFT printing systems) (application number: PN2316);

" the accurate control of printhead temperature pulse " (Accurate control of temperature pulses in printing heads) (application number: PN2317);

" data in the monolithic LIFT printhead distribute " (Data distrbution in monolithic LIFT print heads) (application number: PN2318);

" the page or leaf image and the tolerance route device that are used for the LIFT print system " (Page image and fault to1erance routing device for LIFT printing systems) (application number: PN2319); And

" the removable fluid under pressure ink cartridge of LIFT printer " (A removable pressurized liquid ink cartridge for LIFT printers) (application number: PN2320).

The image of printhead is processed

The target of print system of the present invention is to obtain such print quality, and it is equivalent to the quality of the Colorful publishing thing of the habitual use offset printing technology printing of people. Print resolution with about 1600dpi just can obtain this effect. Yet the printing of 1600dpi is that difficulty is expensive again. Print resolution with 800dpi can obtain similar effect, and dark blue and wine-colored each pixel is with 2, and each pixel of yellow and black is with 1. This color mode is referred to herein as CC ' MM ' YK. If also need high-quality monochrome image to print, also can adopt 2 of each pixels to black. This color mode is referred to herein as CC ' MM ' YKK '.

Described the color mode, tone processing, data compression and the real-time extension system that are suitable for system of the present invention and other print systems in the following Australian patent specification of submitting April 12 nineteen ninety-five, these specifications can be used as reference herein: " the level Four printing ink that is used for the twin-stage colour print " (Four level ink for bi-level color printing) (application number: PN2339);

" compressibility of page or leaf image " (Compression system for page images) (application number: PN2340);

" the real-time extension equipment that is used for the page or leaf image of compression " (Real-time expansion apparatus for compressed page images) (application number: PN2341); And

" document image that is used for the high power capacity compression of digital color printer " (High capacity compressed document image for digital color printers) (application number: PN2342);

" the JPEG compression in the improvement of text " (Improving JPEG compression in the presence of text) (application number: PN2343);

" expansion and the halftoning device that are used for the page or leaf image of compression " (An expansion and halftoning device for compressed page images) (application number: PN2344); And

" improvement of image halftoning " (Improvements in image halftoning) (application number: PN2345).

The application of printhead of the present invention

Method of printing of the present invention and device are fit to widely purposes, comprise below (but being not limited only to): colored and monochromatic office printer, the figure punch that uses in short-term, high-speed figure are printed, are processed chromatograp, on-the-spot colour print, the auxiliary low price printer of printing, adopting the scan-type printhead of offset press, adopt high-speed printer, portable colour and monochrome printers, colour and one-color copier, colour and monochromatic facsimile machine, combination printer, fax and duplicator, the label printing machine of pagewidth printhead,, large space of a whole page plotter, photocopying, be used for the portable printer of printing machine that Digital photographic processes, the numeral of packing into ' vertical bat ' video camera, with the printer of the printer of display screen, PhotoCD image, for portable printer, wallpaper stripper printing machine, indoor character printer, document printing and the cloth print of ' Personal Digital Assistants '.

Described based on print system of the present invention in the following Australian patent specification of submitting April 12 nineteen ninety-five, these specifications can be used as reference herein:

" the high-speed color office printer with the storage of large capacity digital page or leaf image " (A high speed color office printer with a high capacity digital page image store) (application number: PN2329);

" the in short-term digital color printer with the storage of large capacity digital page or leaf image " (A short run digital color printer with a high capacity digital page image store) (application number: PN2330);

" the color digital compression of use LIFT printing technique " (A digital color printing press using LIFT printing technology) (application number: PN2331);

" compression printed in the modulus word " (A modular digital printing press) (application number: PN2332);

" high-speed figure cloth print " (A high speed digital fabric printer) (application number: PN2333);

" photochrome treatment system " (A color photograph coping system) (application number: PN2334);

" the high-speed color photo duplicator of use LIFT print system " (A high speed color photocopier using a LIFT printing system) (application number: PN2335);

" the portable photochrome duplicator of use LIFT technology " (A protable color photocopier using LIFT printing technology) (application number: PN2336);

" photo processing system of use LIFT printing technique " (A photograph processing system using LIFT printing technology) (application number: PN2337);

" the flat paper facsimile machine of use LIFT print system " (A plain paper facsimile machine using a LIFT printing system) (application number: PN2338);

" the photo CD system with integrated printer " (A PhotoCD system with integrated printer) (application number: PN2293);

" color plotter of use LIFT printing technique " (A color plotter using LIFT printing technology) (application number: PN2291);

" notebook with integrated LIFT color printing system " (A notebook computer with integrated LIFT color printing system) (application number: PN2292);

" portable printer of use LIFT print system " (A portable printer using a LIFT printing system) (application number: PN2300);

" facsimile machine with online database and the printing of customization magazine " (Fax machine with on-line database interrogation and customized magazine printing) (application number: PN2299);

" miniature color printer " (Miniature portable color printer) (application number: PN2298);

" color video printer of use LIFT print system " (A color Video printer using a LIFT printing system) (application number: PN2296); And

" integrated printer, duplicator, scanner and the facsimile machine of use LIFT print system " (An integrated printer, copier, scanner, and facsimile using a LIFT printing system) (application number: PN2297).

To printing the compensation of headring border condition

The print system of throwing in as required have consistently and predictable droplet size and position. The unnecessary variation of droplet size and position can make the optical density (OD) of print result change, and the print quality of seeing will reduce. These variations should be maintained at minimum ratio in specified droplet volume and pixel gap. Can compensate many environmental variances, in order to its impact is reduced to unconspicuous level. Offer the power of nozzle heater by change, can carry out compensation initiatively to some factor.

The optimum temperature curve that is used for a printhead embodiment is such, namely a flash the chien shih nozzle tip active component rise to injection temperation, at impulse duration this position is maintained injection temperation, and in a flash this position is being cooled to environment temperature.

Because hot memory capacity and the heat conduction property of the various materials that use when making printhead of the present invention, this preferred plan can't realize. Yet, undertaken repeatedly selectedly hand to hand by the finite element model to printhead, just can obtain a curve, utilize this curve sharpening output pulses, so just can improve performance. Can utilize various technology change provides time from power to heater, this comprising, but be not limited in:

1) changes the voltage that is added on the heater

2) width (PWM) of a series of short pulses of modulation

3) frequency (PFM) of a series of short pulses of modulation

In order to obtain accurate result, can simulate the instantaneous hydrodynamic model of Free Surface when needing one in printing ink, to have convection current and ink flow, obtain effective impact of temperature with concrete power curve.

If at the printhead substrate suitable digital circuit is installed, just can controls independently the power that offers each nozzle. A kind of mode of accomplishing this point be on whole print head chip ' broadcasting ' various digit pulse string, and be an amount of train of pulse of each nozzle selection by multiplex electronics.

Some environmental factors that can be compensated in the table of " to the compensation of environmental factor ", have been listed. Pointed out that at this table the optimal compensation to each environmental factor is whole (for whole printhead), (for each chip in the synthetic multi-chip printhead) of chip one by one, still nozzle one by one.＜to the compensation of environmental factor 〉

Compare factor	Scope	Detect or user's control method	Compensation mechanism
				Environment temperature	Whole	Be contained in the temperature sensor on the printhead	Supply voltage or whole PFM figure
Supply voltage changes along with the quantity of effective nozzle	Whole	Predict the quantity of effective nozzle according to print data	Supply voltage or whole PFM figure
				Successively startup generation amount of localized heat along with nozzle	Nozzle one by one	Predict the quantity of effective nozzle according to print data	For each printed dot is selected suitable PFM figure
The size of control ink droplet when each pixel has multidigit	Nozzle one by one	View data	For each printed dot is selected suitable PFM figure
				Nozzle Geometrical change between the wafer	Chip one by one	In factory, measure the data file that offers printhead	The whole PF M figure of print head chip one by one
Heater resistance between the wafer changes	Chip one by one	In factory, measure the data file that offers printhead	The whole PF M figure of print head chip one by one
				The user images Auto-regulating System of Density of Heavy Medium	Whole	User selection	Supply voltage, static accelerating potential, or ink pressure
Reduce method and the threshold temperature of ink surface tension	Whole	Ink cartridge sensor or user selection	Whole PFM figure
				Ink viscosity	Whole	Ink cartridge sensor or user selection	Whole PFM figure and/or clock rate
The dyestuff of printing ink or pigment concentration	Whole	Ink cartridge sensor or user selection	Whole PFM figure
				The printing ink response time	Whole	Ink cartridge sensor or user selection	Whole PFM figure

Do not need all of these factors taken together is compensated in most application scenarios. Some variable has negative effect, and only just needs compensation when requiring very high picture quality.

Print-head drive circuit

Fig. 4 is the schematic block diagram according to the circuit theory of a routine print-head drive circuit of the present invention. This control circuit adopts the supply voltage of analog-modulated, provides it to printhead, thereby realizes the heater power modulation, and the not independently control of power to offering each nozzle. Fig. 4 has represented to adopt the system block diagram of 800dpi pagewidth printhead, and this system adopts CC ' MM ' YK color mode to carry out colour print. Printhead 50 has altogether 79,488 nozzles, and 39,744 main burners and 39,744 redundant nozzles are wherein arranged. Main burner and redundant nozzle are divided into six kinds of colors, and every kind of color is divided into 8 driving phases. Each drives a shift register mutually, is used for the serial data from print head controller ASIC 400 is converted to for the parallel data that starts control circuit for heater. Always have 96 shift registers, 828 nozzles of respectively doing for oneself provide data. Each shift register is made of 828 shift register stage 217, its output by NOT-AND gate 215 and phase enabling signal actuating logic " with ". The output of NAND gate 215 drives an inverter buffer 216, and the latter controls driving transistors 201 again. Driving transistors 201 excitation electric hot heaters 200, it can be the heater 103 shown in Fig. 1 (b). Effective in order during starting impulse, to keep shifted data, stopped the clock of shift register by clock brake 218, it is effective to keep starting impulse, represents the clock brake with single door in the drawings for clear, but can realize with any known error free clock control circuit. The clock that stops shift register can being locked in parallel data in the printhead, but the circuit among the print head controller ASIC 400 has been increased some complexity. According to the state of special signal on the malfunction bus, data shunt 219 sends to main burner or redundant nozzle to data.

Printhead shown in Fig. 4 is through simplifying, and not have to represent for improvement of various devices such as the parts (block) of manufacturing process are fault-tolerant. Be easy to obtain drive circuit for the different structure printhead according to device disclosed herein.

The digital information that represents the print point figure on the recording medium is stored in page or leaf or the range storage device 1513, and it can be identical with the video memory 72 among Fig. 1 (a). Address multiplexer 417 is read 32 bit data that represent a kind of color dot by address choice from page or leaf or range storage device 1513, and produces control signals by memory interface 418. These addresses are produced by address generator 411, and it is ' part of the circuit of every kind of color ' 410, six kinds of color components respectively have a sort circuit 410. The address is to produce according to the position of nozzle with respect to printed medium. Because the relative position of the nozzle of different printheads might be different, address generator is preferably programmable. Address generator 411 produces the address corresponding with the main burner position when normal. Yet, when breaking down nozzle, in fault graph R AM412, can mark the position of out of order jet element. In printer page, read fault graph RAM412. If this memory indicates fault is arranged in jet element, the address just is changed, the address that makes address generator 411 produce corresponding redundant nozzle location. Lock the data of from page or leaf or range storage device 1513, reading with register 413, and converted thereof into four bytes of order by multiplexer 414. Regulate the sequential of these bytes with FIFO415, make itself and the Data Matching that represents other colors. Then cushion these data by buffer 430, thereby consist of 48 main data bus of printhead 50. Because the position potential range print head controller ASIC of printhead is relatively far away, data need buffering. Also consisted of the input of FIFO416 from the data of fault graph RAM412. The output data of the sequential of these data and FIFO415 are complementary, and by buffer 431 bufferings, thereby consist of the malfunction bus.

Programmable power supply 320 provides electric power for printhead 50. The voltage of power supply 320 is subjected to the control of DAC313, and DAC313 is the part of the combination (RAMDAC) 316 of RAM and DAC. RAMDAC 316 comprises a two-port RAM 317. The content of two-port RAM 317 is by microcontroller 315 programmings. Come compensation temperature by the content that changes two-port RAM 317. These values of temperature computation that microcontroller 315 detects according to heat sensor 300. The signal of heat sensor 300 is connected to analog-digital converter (ADC) 311. ADC311 preferably is contained within the microcontroller 315.

Print head controller ASIC400 comprises the control circuit for thermal lag compensation and print density. It is an in time vertiginous voltage that thermal lag compensation requires the supply voltage in printhead Europe 50, and it should be synchronous with the starting impulse of heater. This voltage is by 320 programmings produce to programmable power supply. DAC313 produces the program voltage that a simulated time changes according to the data of reading from two-port RAM 317. Data are read out according to the address that is produced by counter 403. Counter 403 produces the address of a complete cycle during a starting impulse. Because counter 403 is by system clock 408 regularly, thus guaranteed this synchronously, and the highest counting of counter 403 is used as the timing that starts counter 404. Then by the decoding of the counting of 405 pairs of startup counters 404 of decoder, and produce the starting impulse of printhead 50 through the buffering of buffer 432. If the status number of counting is less than the clock periodicity in the starting impulse, counter 403 can comprise a pre-frequency counter. For the thermo-lag of compensating heater accurately, adopt 16 voltage status. These 16 states can be specified with four connecting lines between counter 403 and the two-port RAM 317. Yet these 16 states not necessarily adopt linear interval in time. In order to satisfy the non-linear timing of these states, counter 403 can also comprise a ROM or other devices, in order to counter 403 is counted according to nonlinear mode. Or also can adopt and be less than 16 status number.

Aspect the print density compensation, in each start-up period, the pixel number of an ink droplet of needs (on pixel) printing is counted, detect thus print density. 402 pairs in print picture element (print pel) counter ' print ' the pixel counting. Eight starting impulses respectively there is a print picture element (print pel) counter 402. According to the present invention, the startup number of phases in printhead depends on concrete design. Although and do not require that the startup number of phases must be two multiple, normally four, eight and 16. Print picture element (print pel) counter 402 can be made of combinational logic pixel counter 420, determines in a data segment how many units to be arranged with counter 420. Then by adder 421 and accumulator 422 cumulative these units. Register 423 keeps this cumulative numerical value effective during starting impulse. Multiplexer 401 is selected the output of the register 423 of corresponding current starting impulse according to the decision that starts counter 404. The output of multiplexer 401 has consisted of a part of address of two-port RAM 317. Do not need right ' print ' pixel counts accurately, only needs four highest significant positions of this counting just enough.

The combination of four thermal lag compensation addresses and four print density compensation addresses represents 8 bit address of dual-port RA M317. This expression two-port RAM 317 comprises 256 numerical value that are arranged in two-dimensional array. This two-dimensional representation (being used for thermal lag compensation) time and print density. Can also comprise the third dimension, namely temperature. Because the variation of ambient temperature of printhead is very slow, microcontroller 315 has time enough to calculate the matrix of 256 numerical value that are used for compensation thermo-lag and print density under current temperature. Microcontroller periodically (for example per second several times) detects current printhead temperature, and calculates this matrix.

The clock of printhead 50 is produced according to system clock 408 by printhead clock generator 407, and by buffer 406 bufferings. For ease of test printing head controller ASIC,

Can also comprise jtag test circuit 499.

Comparison with hot ink-jet technology

The table of " comparison between hot ink-jet and the present invention " has been made the comparison of each side to the present invention and thermal inkjet-printing technology.

Because the present invention and hot ink-jet technology all are the as required jettison systems that adopts thermal excitation and liquid ink, can directly compare between the two. Although they look like similarly, these two kinds of technology are by different principle work.

The thermal inkjet-printing technology adopts following basic principle of operation. The thermal pulse that produces by resistance heated forms rapidly bubble in liquid ink. Can be fast and form reliably bubble by making that printing ink is overheated, thus before bubble is assembled fully to the enough heats of printing ink transmission. For water-based inks, the temperature of printing ink need to reach 280 ℃ to 400 ℃. High viscosity inks ink droplet in the pressure wave compressing hole that the formation of bubble causes. Bubble disappears subsequently, and picks up ink from ink storage device is loaded nozzle again. Because the packing density of nozzle is very high, and uses ripe ic manufacturing technology, the thermal inkjet-printing technology has commercially obtained huge success. Yet, the thermal inkjet-printing technology faces like this some obvious technical problems, comprising the yield rate of multipart accurate assembly, device, image resolution ratio, ' difficulty that pepper ' noise, print speed, driving transistors power, power consumption, the splash of formation ink droplet, thermal stress, thermal expansion difference, section a word used for translation oil (kogation), cavitation, distillation diffusion and ink composition cause.

Printing technique of the present invention has many advantages of thermal inkjet-printing technology, and has eliminated the intrinsic many problems of thermal inkjet-printing technology fully or basically.

Comparison between＜hot ink-jet and the present invention 〉

	Hot ink-jet	The present invention
			Ink droplet is selected mechanism	The pressure wave that the bubble that generates by thermoinduction causes sprays ink droplet	Select to reduce the mechanism of surface tension or viscosity
The ink droplet separation mechanism	Select mechanism identical with ink droplet	Select to approach static, magnetic field and additive method
			Basic ink carrier	Water	Water, micro emulsion, alcohol, ethylene glycol, or hot melt
Printhead configuration	Accurately assemble nozzle plate, oil ink passage and substrate	Monolithic
			Every printing expense	Because the life-span of printhead is limited and printing ink is very expensive, expense is very high	Because the durability of printhead and the printing ink that adapts to wide region, expense can reduce
The formation of ink droplet splash	Affect significantly picture quality	Can not form the ink droplet splash
			The operating temperature of printing ink	280 ℃ to 400 ℃ (high temperature limit use and the ink composition of dyestuff)	About 70 ℃ (depending on ink composition)
The heater peak temperature	400 ℃ to 1000 ℃ (high temperature can reduce device lifetime)	About 130 ℃
			Air pocket (heater is owing to breaking of bubble worn and torn)	The serious problems of restriction print head longevity	There is not (not forming bubble)
Section's a word used for translation oil (kogation) (heater is covered by the printing ink ash)	The serious problems of restriction print head longevity and ink composition	There is not (temperature of water-based inks is no more than 100 ℃)

Distillation diffusion (because pressures cycle forms bubbles of ink)	The serious problems of restriction ink composition	Because ink pressure can not become negative value, does not have this problem
			Resonance	The serious problems of limits nozzle structure and repetition rate	Affect very little because pressure wave is very little
True resolution	Maximum is about 800dpi	Maximum is about 1600dpi
			From the cooling operation	There is not (needing high-energy)	Have: the printing ink of printing has been taken away ink droplet and has been selected energy
Ink ejection velocity	High (approximately 10m/sec)	Low (approximately 1m/sec)
			Disturb	Serious problems need accurate acoustic construction, the speed that limits nozzle refills	Low speed, and the pressure when spraying ink droplet is low, therefore disturbs very little
The operation thermal stress	The serious problems of restriction print head longevity	Low: the maximum temperaturerise of heater center approximately is 90 ℃
			Make thermal stress	The serious problems of restriction printhead size	Identical with the CMOS manufacturing process of standard
Ink droplet is selected energy	About 20 μ J	About 270nJ
			The heater pulse cycle	About 2-3 μ s	About 15-30 μ s
The heater pulse mean power	About 8 watts of each heater	The about 12mW of each heater, the specific heat ink-jet is low more than 500 times
			Heater pulse voltage	About 40V	About 5-10V
Heater peak pulse electric current	Each heater needs 200mA usually, needs bipolar or very large MOS driving transistors	The about 4m A of each heater can use little MO S driving transistors
			Fault-tolerant	Do not implement	Implement easily, can make yield rate and Reliability Enhancement
Restriction to ink composition	Comprise section a word used for translation oil (kogation), many restrictions such as unclean	The temperature coefficient of surface tension or viscosity must be negative value

Ink pressure	Below the atmospheric pressure	About 1.1atm
			Integrated drive electronics	Because drive current is large, usually needs bipolar circuit	CMOS, nMOS, or bipolar circuit
Thermal expansion difference	Obvious problem to large-scale printhead	Structure with monolithic reduces this problem
			The pagewidth printhead	Subject matter is yield rate, cost, structure precision, print head longevity, and power consumption	By fault-tolerant acquisition high finished product rate, low cost. Because low-power consumption can cooling itself.

Yield rate and fault-tolerant

As a rule, if monolithic integrated optical circuit function imperfection during fabrication can't be repaired. The percentage of the operational device that produces by wafer process is called as yield rate. Yield rate has direct impact to manufacturing cost. The manufacturing cost of the device of 5% yield rate is than expensive ten times of the manufacturing costs of the identity unit with 50% yield rate.

Here mainly contain three kinds of yield rate measurement indexes:

1) fabrication yield

2) wafer separation yield rate

3) final test yield rate

For the situation of large form, the wafer separation yield rate is normally to the strictest restriction of total yield rate. It is very large comparing with typical VLSI circuit according to full pagewidth color print head of the present invention. Satisfied wafer separation yield rate is crucial problem to effective manufacturing cost of this printhead.

Fig. 5 is for the wafer separation yield rate of the colored A4 printhead of the full pagewidth of monolithic of the present invention embodiment and the relation curve of defect concentration. Printhead has 215mm long and 5mm is wide. Be to calculate according to the method for Murphy without fault-tolerant yield rate 198, this is a kind of yield prediction method of extensive use. If defect concentration is defective of every square of cm, the yield rate that dopes with the method for Murphy is less than 1%. This means that the printhead of making has more than 99% must be abandoned. Low like this yield rate is very undesirable, because the manufacturing cost of printhead is too high.

The method of Murphy is similar to the impact of uneven distribution defective. Fig. 5 also comprises one without the curve of fault-tolerant yield rate 197, and it has introduced a defective grouping coefficient, thereby is clearly shown that the grouping of defective. Defective grouping coefficient be not one during fabrication can be controlled parameter, but can be used as a feature of manufacturing process. The coefficient that defective can be divided into groups in manufacturing process is predefined for 2, and in this case, the perspective view of yield rate roughly conforms to the method for Murphy.

A method that solves low yield rate problem is that introducing is fault-tolerant, namely comprises redundant functional unit at chip, is used for replacing the functional unit of fault.

In integrated circuit (WSI) device of memory chip and most of wafer-scales, the physical location of redundant pair unit on chip is unimportant. Yet in printhead, redundant pair unit may comprise one or more printing starter. The page that they are printed with respect to needs must have fixing spatial relationship. In order to print a point at same position as out of order driver, redundant driver must not misplace in non-scanning direction. Yet failed drive can be replaced by the redundant drive that misplaces in the scanning direction. In order to guarantee that redundant drive can print a point at same position as failed drive,

Can change the data timing of redundant drive, thus the dislocation on the compensated scanning direction.

In order to replace all nozzles, a complete cover nozzle must be arranged, so just consisted of 100% redundancy. Yet the requirement of 100% redundancy need to make chip area double usually, is replacing can reducing significantly elementary yield rate before the redundancy unit, and will offset so fault-tolerant most of advantage of bringing.

Yet, according to printhead embodiment of the present invention, the minimum physical size of print head chip depends on the pagewidth that is printed, and print head chip holds breakable character, and the manufacturing process restriction that runs into when chip provides the oil ink passage of printing ink behind in assembling. The actual minimum dimension that is used for the full duration full color printhead of the printing A4 size page approximately is 215mm^*5mm. When adopting 1.5 μ m CMOS manufacturing technology, this size allows to hold 100% redundancy, and can not increase significantly chip area. Therefore, under the condition that can obviously not reduce elementary yield rate, can realize high-caliber fault-tolerant.

When comprising in the device when fault-tolerant, can not adopt the yield formula of standard. Otherwise in yield formula, must embody particularly and comprise fault-tolerant mechanism and degree. Fig. 5 has represented to be used for the fault-tolerant sorting yield rate of the colored A4 printhead of full page face, comprising various forms of fault-tolerant, has comprised its model in yield formula. This curve represents concrete yield rate with the function of defect concentration and defective grouping. The yield rate perspective view that represents in Fig. 5 shows, under identical creating conditions, adopts fully fault-tolerant networks can make the wafer separation yield rate from bringing up to more than 90% below 1%. Can make like this manufacturing cost reduce by 100 times.

For the printhead that comprises thousands of printing nozzles, fault-tolerantly can improve widely yield rate and reliability, thus just can the actual printhead of making pagewidth. But fault-tolerant is not core content of the present invention.

Described in the fault-toleranr technique of throwing in as required in the print system in the following Australian patent specification of submitting April 12 nineteen ninety-five, these specifications can be used as reference herein:

" the integrated tolerance in printing mechanism " (Integrated fault tolerance in ptinting mechanisms) (application number: PN2324);

" component tolerances in the integrated print head " (Block fault tolerance in integrated printing heads) (application number: PN2325);

" nozzle that is used for integrated print head tolerance copies " (Nozzle duplication for fault tolerance in integrated printing heads) (application number: PN2326);

" detection of defective nozzle in the printhead " (Detection of faulty nozzles in printing heads) (application number: PN2327); And

" tolerance of large capacity force of impression " (Fault tolerance in high Volume printing presses) (application number: PN2328).

Print system embodiment

In Fig. 6, represented to adopt the schematic diagram of a kind of digital and electronic print system of printhead of the present invention. The figure shows a monolithic print head 50, it is printed on the piece image 60 that is made of many ink droplets on the recording medium 51. Typical media are paper, also can be that common transparent film, fabric or many other can be admitted the planar materials of printing ink. Printed image is provided by an image source 52, and it can be any image format that can convert two-dimensional pixel array to. Typical image source has the image of image analyzer, stored digital, the image of using PDL (PDL) to encode, Adobe Postscript for example, Adobe Postscript level 2, or Hewlett-Packard PCL 5, the page-images of utilizing raster generator to produce by routine call, Apple QuickDraw for example, Apple Quickdraw GX, or Microsoft is GDI, or the text of electronic form ASCII for example. This view data is converted to the two-dimensional pixel array that is fit to specific print system by image processing system 53. Image can be colored or monochromatic, and each pixel can have the data between 1 to 32 usually, depends on the form of image source and concrete print system. If image source is a kind of page figure, image processing system can adopt raster image processor (RIP), if image source also can adopt the two dimensional image treatment system from a scanner.

If need the image of continuous tone, just need a halftone process system 54. Suitable halftone process mode is based on " order is trembled or the spaced point (dispersed dot ordered dither of error diffusion) of error diffusion ". Or adopt known " random screening or frequency modulation(PFM) screening (stochastic screening or frequency modulation screening) ". The halftone process system of " the boundling point (clustered dot ordered dither) that order is trembled " when here recommend adoption is not generally used for hectographic printing is because adopt this technology can unnecessarily waste effective image resolution ratio. The output of halftone process system is binary system monochrome or the coloured image that is fit to the resolution ratio of print system of the present invention.

Binary picture is to be processed by data phasing circuit 55 (it can be contained among the print head controller ASIC 400 shown in Figure 4), and data phasing circuit 55 offers data shift register 56 to pixel data according to correct order. For the arrangement of compensating jet and the movement of paper, need to be to the data sequencing. After data were loaded in the shift register 56, data were provided for heater drive circuit 57 in parallel mode. Drive circuit 57 is connected to corresponding heater 58 potential pulse that produces by pulse shaper 61 and voltage regulator 62 according to correct time with electronic circuit. The tip of heater 58 heated nozzles 59 affects the physical characteristic of printing ink. Ink droplet 60 breaks away from nozzle according to the figure corresponding with the digit pulse that offers heater drive circuit. Ink pressure in the ink storage device 64 is regulated by pressure regulator 63. By selected ink droplet separator ink droplet chosen in the ink droplet 60 is separated from the printing ink main body, and touch recording medium 51. During printing, utilize paper induction system 65 to make recording medium 51 mobile continuously with respect to printhead 50. If printhead 50 has covered the whole width of the print range of recording medium 51, recording medium 51 only needs to move in one direction printhead 50 then can keep fixing. If use less printhead 50, just need to adopt raster scanning system. Typical method is the minor face scanning and printing head 50 along recording medium 51, simultaneously along its long limit moving recording media 51.

The computer simulation of nozzle dynamic characteristic

Utilize computer that the details of operation of printhead of the present invention has been made comprehensive simulation. Fig. 8 to 18 is results of some simulations, and the operation of this preferred nozzle embodiment is to reduce surface tension by electrical heating to select ink droplet, and combines with the ink droplet separate mode of static.

The characteristic of the phenomenon of observation is extremely useful to determining to be difficult to directly in computer simulation. Owing to following several reasons, the operation of nozzle is difficult to observe by experiment, and these reasons comprise:

1) nozzle of experiment is miniature, and the feature of important phenomenon is less than 1 μ m.

The time scale of 2) spraying ink droplet only has several microseconds, needs high observation speed.

3) important phenomenon occurs in opaque inside of solid material, can not directly observe.

4) for example heat flow and fluid velocity vector field are difficult to directly observe with any scale some important parameters.

5) expense of manufacturing experiment nozzle is very high.

Computer simulation has overcome above-mentioned problem. The software kit that is used for a kind of advanced person of fluid dynamic simulation is Fluid Dynamics International Inc.of Illinois, USA

(FDI) FIDAP that makes. FIDAP is the registration mark of FDI. On market, also can obtain other simulation softwards, but why select FIDAP to be because it at the fluid dynamic simulation of transition, energy shifts, and the aspect such as surface tension calculating has very high precision. The FIDAP version that adopts is FIDAP7.51.

Combining energy in simulation shifts and the hydrodynamic model. Because this routine nozzle is columnar, adopts axisymmetric analog form. The shape of cylinder can produce four kinds of deviations. Here it is and being connected of heater, because the laminar airflow that the movement of paper causes, gravity (if printhead is not vertical), and the adjacent nozzle that exists on the substrate. These factors are very little on the impact that ink droplet sprays.

In order to utilize FIDAP7.51 in the transient process of Microsecond grade, to obtain the transient state Free-surface model of convergence by the surface tension that changes by the micron order scale, need to take nondimensional model.

Only need to simulate the zone of nozzle tip, because select relevant most of phenomenons all to appear in this zone with ink droplet. The scope of simulation is the 40 μ m that stretch out of the symmetry axis from nozzle.

When beginning to simulate, the printing ink in whole nozzle and the device all is in environment temperature, is 30 ℃ under this condition. During operation, the device environment temperature can be slightly higher than atmospheric temperature, because can reach certain equalization temperature in the whole cycle of spraying many ink droplets, this temperature depends on print density. Each most of energy of ink droplet of selecting has been taken away by ink droplet. Because the heat conductivity of silicon chip is very high, and the convection current in the printing ink, in the interval of spraying ink droplet, can distribute very equably the after-heat in the nozzle.

The geometry of simulation nozzle

Fig. 7 is illustrated in the embodiment of imitated in a this simulation ideal nozle.

Nozzle by body plan on a monocrystalline silicon substrate 2020. The boron doped silicon layer 2018 that has an extension on the substrate, it is used to prevent etching when making nozzle. The silicon layer 2019 of extension is for effective substrate of making CMOS driving transistors and data allocation circuit. The CMOS technique which floor deposition is arranged at this substrate. This wherein has metal level 2024, the second metal level 2025 and passive oxidation layer 2026 between a thermal oxide layer 2021, the first interlevel oxide layer 2022, the first metal layer 2023, the second layer. Processed wafer is made nozzle and heater in order. These structures comprise effective heater 2027 (a), the ESD screen layer 2027 (b) that utilizes " remaining " heater material to make, and silicon nitride passivation 2028.

Upward form narrow " edge " by the heater top that is etched in to each oxide layer. Doing like this is in order to reduce " thermal mass " of the material around the heater, and prevents that printing ink from spreading on the surface of printhead.

Filling electrically conductive ink 2031 in printhead. Apply an electric field with two electrodes at printhead, electrode and printing ink form and electrically contact, and another electrode is located at the recording medium back.

The radius of nozzle is 8 μ m, and diameter is proportional with it.

The theoretical foundation of calculating

In the FIDAP7.0Thoery Manual (in April, 1993) that FDI publishes, describe the theoretical foundation that adopts Finite Element Mothod to carry out hydrodynamic analysis and power conversion calculating in detail, and the method for in the FIDAP computer program, using this theoretical foundation, foregoing can be used as reference of the present invention.

Material behavior

Provided the approximate physical characteristic of material at the table of " be used for FIDAP simulation material behavior ", these materials can be used to make printhead of the present invention.

" printing ink " that uses in this simulation is the water-based inks that has added 25% pigment. In printing ink, contain the suspended particulates of hexadecanoic acid, in order to surface tension is reduced significantly along with temperature. The employing surface tension instrument is measured the surface tension under the various temperature.

Table in " material behavior that is used for the FIDAP simulation " has provided the numerical value that uses in the simulation of adopting the FIDAP program. Most of numerical value are from direct measurement, or take from CRC chemistry and physics handbook " (Handbook of Chemistry and Physics); 72nd edition, or the chemical handbook of Lange " (handbook of chemistry), 14th edition.

＜be used for the material behavior of FIDAP simulation 〉

Characteristic	Material or temperature	Physical quantity	Dimensionless numerical value
				Characteristic length (L)	All	1μm	1
Characteristic velocity (U)	Printing ink	1m/s	1
				Characteristic time	All	1μs	1
Time period	All	0.1μs	0.25
				Environment temperature	All	30℃	30
Boiling point	Printing ink	103℃	103
				Viscosity (η)	At 20 ℃	2.306cP	3.530
Viscosity (η)	At 30 ℃	1.836cP	2.810
				Viscosity (η)	At 40 ℃	1.503cP	2.301
Viscosity (η)	At 50 ℃	1.259cP	1.927
				Viscosity (η)	At 60 ℃	1.074cP	1.643
Viscosity (η)	At 70 ℃	0.930cP	1.423
				Viscosity (η)	At 80 ℃	0.816cP	1.249
Viscosity (η)	At 90 ℃	0.724cP	1.108

Viscosity (η)	At 100 ℃	0.648cP	0.993
				Surface tension (γ)	28℃	59.3mN/m	90.742
Surface tension (γ)	33℃	58.8mN/m	89.977
				Surface tension (γ)	38℃	54.1mN/m	82.785
Surface tension (γ)	43℃	49.8mN/m	76.205
				Surface tension (γ)	47℃	47.3mN/m	72.379
Surface tension (γ)	53℃	44.7mN/m	68.401
				Surface tension (γ)	58℃	39.4mN/m	60.291
Surface tension (γ)	63℃	35.6mN/m	54.476
				Surface tension (γ)	68℃	33.8mN/m	51.721
Surface tension (γ)	73℃	33.7mN/m	51.568
				Pressure (P)	Printing ink	10kPa	15.3
Thermal conductivity (k)	Printing ink	0.631Wm -1k -1	1
				Thermal conductivity (k)	Silicon	148Wm -1k -1	234.5
Thermal conductivity (k)	SiO 2	1.5Wm -1k -1	2.377
				Thermal conductivity (k)	Heater	23Wm -1k -1	36.45
Thermal conductivity (k)	Si 3N 4	19Wm -1k -1	30.11
				Concrete heat (cp)	Printing ink	3,727Jkg -1k -1	3.8593
Concrete heat (cp)	Silicon	711Jkg -1k -1	0.7362
				Concrete heat (cp)	SiO 2	738Jkg -1k -1	0.7642
Concrete heat (cp)	Heater	250Jkg -1k -1	0.2589
				Concrete heat (cp)	Si 3N 4	712Jkg -1k -1	0.7373
Density (ρ)	Printing ink	1.036gcm -1	1.586
				Density (ρ)	Silicon	2.320gcm -1	3.551
Density (ρ)	SiO 2	2.190gcm -1	3.352
				Density (ρ)	Heater	10.50gcm -1	16.07
Density (ρ)	Si 3N 4	3.160gcm -1	4.836

Hydrodynamic analogy

Fig. 8 (a) expression offers the power of heater. The peak power that offers heater is 40m W. This power is subject to impulse modulation, thereby obtains the ideal power that moment offers heater. The interval of each output pulses is 0.1 μ s, and the energy of 4nJ is transmitted in each pulse to heater. 10 μ s enter simulation after the ink droplet strobe pulse begins, in order to make meniscus enter its resting position. The gross energy that is delivered to during the ink droplet strobe pulse on the heater is 276nJ.

Fig. 8 (b) is illustrated in the temperature on interior each aspect of nozzle in the simulation process.

Point A is on the contact point of printing ink meniscus and nozzle edge. For effectively operation, the temperature of this point should rise to approach still as far as possible and be no more than the boiling point of printing ink, and maintains this temperature during the ink droplet strobe pulse. " the band point " temperature curve is to be caused by the pulse frequency modulated power that is applied on the heater. If increase pulse frequency and suitably reduce pulse power, this " point " reduced.

Point B is a point on the printing ink meniscus, approximately is in the centre of meniscus center and nozzle tip.

Point C is apart from the point at nozzle center 20 μ m places on the silicon chip surface. This point demonstrates very little apart from the temperature rise when selecting ink droplet on the very near point of nozzle. So just allow to settle such as active devices such as driving transistors in the position very close to nozzle.

Fig. 9 represents position and the time curve on the meniscus central point.

Figure 10 represents each meniscus position and the shape constantly during the ink droplet strobe pulse. From the starting point displaying time of ink droplet strobe pulse, (beginning simulation during 10 μ s), and interval 5 μ s are until heater pulse begins afterwards 60 μ s.

Figure 11 be illustrated in the ink droplet strobe pulse begin before the model of temperature isopleth in the nozzle, simulation during since 9 μ s. The tension force on surface and the synthetic effect of ink pressure and outside steady electric field form balance.

Figure 12 is that the ink droplet strobe pulse begins the afterwards temperature isopleth in nozzle of 5 μ s, simulates since 15 μ s. The capillary reduction in nozzle tip place is taken away rapidly meniscus heat on every side so that extend on the surface on this point. Because capillary reduction can not form balance with the synthetic effect of ink pressure and outside steady electric field, printing ink has begun mobile. Because the viscosity resistance of nozzle wall, the translational speed at meniscus center is faster than the outside. In Figure 12 to 17, represented since 35 ℃ and the temperature isopleth that increases by 5 ℃ of intervals.

Figure 13 represents that the ink droplet strobe pulse begins the afterwards temperature isopleth in nozzle of 10 μ s, simulates since 20 μ s.

Figure 14 represents that the ink droplet strobe pulse begins the afterwards temperature isopleth in nozzle of 20 μ s, simulates since 30 μ s.

Figure 15 represents that the ink droplet strobe pulse begins the afterwards temperature isopleth in nozzle of 30 μ s, simulates since 40 μ s. That nozzle begins to cool down after the ink droplet strobe pulse finishes 6 μ s at this moment.

Figure 16 represents that the ink droplet strobe pulse begins the afterwards temperature isopleth in nozzle of 40 μ s, simulates since 50 μ s. From this model can find out the most of energy of determining of ink droplet strobe pulse chosen ink droplet taken away.

Figure 17 represents that the ink droplet strobe pulse begins the afterwards temperature isopleth in nozzle of 50 μ s, simulates since 60 μ s. Chosen ink droplet begins " contraction " at this moment, and enters the ink droplet separation phase.

Figure 18 represents the streamline in the nozzle with the same time of Figure 17.

Three orders of ink droplet injection cycle mutually in, the time period roughly is:

1) the heater Energizing cycle of 24 μ s

2) beginning ink droplet during 60 μ s separates

3) return resting position behind the 40 μ s

Total time is 124 μ s, and it approximately is 8 KHz that the maximum that obtains is thus thrown in repetition rate (input frequency).

The ink droplet separate mode that approaches

Rely on the proximity printing media to come the optimum operation condition of separating liquid ink drop as follows:

1) the selected poor surface roughness greater than printed medium of the meniscus position with unselected ink droplet.

2) surface roughness of printed medium is less than 30% of the ink drop diameter.

3) advancing the speed greater than the speed that under the ink pressure that applies, from nozzle, flows out printing ink owing to wetting printed medium surface and/or the inner ink drop amount that increases of infiltration porous printed medium.

The radius of nozzle, ink type, media and print resolution can satisfy these conditions in very wide scope.

In the hot melt printing technique, the ink droplet that dissolves will solidify when touching printed medium, and therefore, the characteristic that requires to make printing ink suck printed medium just becomes inessential.

Represented operating principle near the separation printing type to 19 (i) at Figure 19 (a). In this case, ink droplet is selected by the electric heating transmitter, and the tip of transmitter heated nozzle is so that the temperature at meniscus place raises. The rising of temperature causes printing ink to flow out from nozzle tip so that surface tension is reduced to below the critical surface tension.

At Figure 19 (a) in 19 (i), the 1st, the ink droplet of selecting, the 10th, produce the nozzle of selecting ink droplet, 11 is nozzles, but heater wherein 103 is not activated, therefore there are not selected ink droplet, the 5th, the moving direction of printed medium, the 100th, printing ink main body, the 101st, silicon, the 102nd, silica, the 103rd, electric heating driver (being also referred to as " heater "), the 109th, the hydrophobic layer of printhead.

The sectional view of two adjacent nozzles 10 that Figure 19 (a) expression remains static. Nozzle is with very approaching in the recording medium that direction 5 moves with respect to nozzle. From the plane of figure, the cross section of nozzle becomes miter angle with the media moving direction. Nozzle 10 and 11 representatives are at two staggered nozzles crossing over a pixel width perpendicular to the direction of drawing. A hydrophobic layer 109 is arranged on the whole surface of nozzle, and printing ink 100 is hydrophilic. Printing ink is under pressure, thereby the meniscus of printing ink is protruded.

Figure 19 (b) expression is just after the heater 103 of nozzle 10 has applied a driving pulse, still less than the printing ink in two nozzles in the situation that pulse is provided to nozzle 11. Heat is transmitted to ink pellet surface, and the temperature rise that causes thus reduces the local surface tension of printing ink. Capillary reduction can be the result of the natural property of printing ink itself, but preferably promotes surface tension to reduce with a kind of additive in the printing ink, in order to impel surface tension to descend significantly under the heating-up temperature of printing ink. This additive can be a kind of surfactant, and it is the solia particle state that suspends under static temperature, but being activated Shi Zehui at heater dissolves. Under solid state, the effect of surfactant effects on surface tension force is very little. When dissolving, surfactant molecule flow to rapidly ink pellet surface, so that surface tension reduces significantly. The surfactant that uses in this occasion is the 1-hexadecane, and this is that a kind of molten point is 50 ℃ 16 carbon alcohol (16carbon alcohol).

The ink droplet of Figure 19 (c) after the expression short time develops situation. Owing to successively decrease to the surface tension at meniscus center from nozzle tip, and because viscous effect has slowed down near the movement of the printing ink of nozzle wall, selected ink droplet 1 is columniform substantially. Do not apply in this case outside static or magnetic field, and action of gravitation is also not obvious on so little size.

The ink droplet 1 that Figure 19 (d) expression is selected is in the situation of the moment of contact history media 51. " inclination " of selected ink droplet is that this air-flow is that the movement of recording medium causes because the laminar airflow between printhead and the recording medium 51 causes. Under many actual conditions, recording medium is paper normally, and from the scale of distance between nozzle and the recording medium, the surface of paper is coarse. Such roughness can make ink droplet 1 change with contacting in time of recording medium 51, thereby the area of print point is changed. If use the paper film, and/or before just will printing, make recording medium pass through pinch roller, just can reduce this variation as far as possible.

Situation when the selected ink droplet of Figure 19 (e) expression begins " infiltration " recording medium 51.

The selected state of ink droplet after the short time of Figure 19 (f) expression. The speed that recording medium absorbs printing ink approximately is directly proportional with the gradient of infiltration. In the many fibrous recording medium of for example paper, the circle that contacts between printed medium and the printing ink meniscus can be along with recording medium is infiltrated in the horizontal absorption of printing ink. This is not by complete wetting because of surperficial fiber.

The degree of printing ink inflow recording medium depends primarily on the composition of printed medium. Under many occasions, if before printing wetting media, printing ink just can flow into recording medium 51 quickly. Can come wetting media by a series of pinch rollers. It is known providing continuously the technology of uniform liquid-covered with pinch roller in hectographic printing industry. Most of hectographic printing system adopts the damping pinch roller that the film of the aqueous solution is provided on the type plate, and provides one deck ink film with the printing ink pinch roller.

Situation when the selected ink droplet 1 of Figure 19 (g) expression has just separated from printing ink main body 100. Surpassed the speed that pressurized printing ink flows out if printing ink flows into the speed of porous recording medium 51 from nozzle 10, printing ink will separate. With many kinds of printing ink, media and spout radius can obtain this result. Also can use the media of atresias such as plastics or metal film. In this case, when the wetting atresia media of ink droplet, if the speed that its volume increases has surpassed the speed that printing ink flows out from nozzle 10, ink droplet will separate. Under some combination of printing ink and atresia media, moistening in order to impel media, may need to be coated with in the media one deck additive.

Selected ink droplet 1 major part of Figure 19 (h) expression has been infiltrated the situation after the recording medium. Momentum when printing ink returns nozzle drives the meniscus at nozzle 10 places by its resting position. Compare with habitual hot ink-jet or piezoelectric inkjet system, the degree of this " overshoot " is very little.

Figure 19 (i) expression meniscus has been got back to the nozzle 10 after the resting position, and can accept next ink droplet strobe pulse. As shown in FIG., selected ink droplet 1 is sucked printed medium 51 fully. The speed that absorbs depends primarily on printed medium, and above-mentioned selected ink droplet 1 may also not be completely absorbed when the ink droplet of different colours is printed on the same position. This phenomenon can be damaged print quality in some cases, just can use if so the stronger printed medium of absorbability, or the printing ink of use heterogeneity, can use the larger printhead in interval between the color, can heat printed medium and impel its rapid draing, or can be in conjunction with using above-mentioned technology.

In approaching the separation printing type, use sonication printing ink

In proximity printing of the present invention system, suitably printing ink is applied sound wave and can obtain following effect:

1) if sound wave and ink droplet growth cycle are matched, reaching maximum printing ink forward direction speed during the cycle, can promote the ink droplet Fast Growth.

2) when the ink droplet disengaging time matched with the cycle of reducing ink pressure, because the printing ink that flows out from nozzle is less, and printing ink can separate earlier, can reduce the amount of ink of being carried to recording medium by a selected ink droplet.

The intensity of variation of the amount of ink of 3) carrying to recording medium can reduce, because the time of contact of selected ink droplet and the impact that disengaging time all is subject to sound wave can produce sound wave according to very high precision and stable amplitude.

4) can further replace dyestuff with pigment, because printing ink is subject to the even stirring of sound wave, reduce the precipitation of pigment in printing ink, this is a subject matter of pigment.

5) reduce the problem that nozzle is stopped up by dry ink, because near the printing ink of meniscus has been stirred in the even motion of printing ink meniscus, used the printing ink of " fresh " to replace dry printing ink.

Figure 20 (a) expression is applied to the sound wave 820 on the printing ink.

Figure 20 (b) is a space/time diagram, has represented that the printing ink of the selected non-selected ink droplet 822 of ink droplet 821 Buddhist monks is along the residing position of nozzle-axis. Curve along nozzle-axis among a small circle in represented the relation of printing ink and time, its scope extends to very small distance in the paper 51 (at the curve top) from the very small distance of printing ink 100 (in the bottom of curve) body interior.

Two curves are overlapping, so that ink droplet and the unselected ink droplet directly relatively selected.

The printing ink position curve of unselected ink droplet 822 demonstrates the pure oscillation with sound wave 820 same frequencys, but certain phase shift Δ φ is arranged. The degree of phase shift depends on the shape and size of printing ink nozzle and ink storage device, also has the fluid dynamic properties of printing ink. When frequency of sound wave near nozzle in during the resonant frequency of printing ink, phase shift is near 90 °. By changing the phase place for generation of the driving voltage of the piezoelectricity of sound wave or other transducers, just can compensate phase shift. As shown in the figure, the waveform of unselected ink droplet is sinusoidal wave. Actual shape has obvious harmonic distortion, and depends on the geometry of nozzle tip and the fluid dynamic properties of printing ink.

Figure 20 (b) is specifically related to have eight and drives mutually and the printhead embodiment of four kinds of colors (for example CMYK color). Only represented a kind of ink colors among the figure. The sound wave phase place of other ink colors and 90 ° of the phase phasic differences of sound wave 820,180 ° and 270 °. Eight in the ink droplet spraying cycle drive two cycles that phase place extends to sound wave 820. In an ink jet circulation, every kind of ink colors has two to drive phase. Their sound wave is separated by 360 °, and does not provide to a nozzle, but offers staggered nozzle. Cycle 829 and 831 is heater-driven cycles (in this case, nozzle is equipped with selected ink droplet 821) of two orders of a nozzle. In the cycle 831, the heater of other nozzles of same ink colors can start.

When heater was switched at 823 places, the printing ink location track of selected ink droplet 821 began to break away from the printing ink location track of unselected ink droplet 822. Under the effect of sound wave 820, reaching maximum forward speed during the cycle, can help the printing ink in the nozzle to flow out. Along with the balance between the ink pressure of surface tension and vibration is broken, in the time 824 irreversible disengaging occurs. Printing ink continues to gush out from nozzle, until printing ink touches recording medium 51 in the time 825. The wetting recording medium 51 of printing ink the surface and be inhaled into recording medium, shown in the space-time zone 832 among the figure, printing ink and recording medium are overlapping. When entering and/or having surpassed the speed that printing ink flows out along the speed of the volume flow on recording medium surface from nozzle, at the time and 826 places, position that separate, selected ink droplet 821 separates from the main body of printing ink 100. After 826 separation is instantaneous, stays printing ink in the recording medium 51 and the printing ink meniscus of printing ink 100 main bodys and all can shrink rapidly. If at certain hour, namely when flowing back to nozzle, unselected ink drop reduces ink pressure, can help to separate.

On burble point 826, the printing ink of nozzle one side is got back in the nozzle rapidly under the ink surface tension effect. On the resonant frequency of the printing ink at nozzle tip place, the printing ink meniscus is subject to damped oscillation at short notice. The vibration that this damped oscillation and sound wave cause is overlapping. In most of the cases, do not need can not make the resonant frequency of printing ink in the nozzle and frequency of sound wave to be complementary yet. In the embodiment shown in Figure 20 (b), the heater connection cycle is 18 μ s, and the ink droplet spraying cycle is 144 μ s. The cycle of sound wave is 72 μ s, and therefore, the frequency of sound wave is 13.8 KHz. The resonant frequency of column printing ink is 25KH z.

In the time 827, sound wave is in identical phase place with heater starting point 823, and the printing ink meniscus of unselected ink droplet 822 recovers static oscillatory regime not yet fully. Yet another nozzle of identical ink colors was got ready for the startup of heater in the cycle 830 in the time 827. In the ensuing time 828, sound wave is in identical phase place with heater starting point 823, and the heater of same nozzle can start again, because meniscus has returned to static oscillatory regime basically. As shown in the figure, the inked areas 832 that has been inhaled into recording medium 51 is thicker at first, later on along with gradually attenuation of time. Actual inked areas only can attenuation in the recording medium, slows down, and stops at certain thickness at last. The inked areas attenuation is that the position of printing ink is the axis along nozzle because Figure 20 is a width of cloth space/time diagram, and recording medium 51 moves with respect to nozzle-axis. At times 833 place, the selected ink droplet of the next one in this nozzle has arrived the edge of the recording medium that a upper ink droplet passed through. Second ink dot flows into recording medium, is combined with first ink dot, thereby forms continuous ink lay when the Continuous Selection ink droplet.

A kind of simple mechanism that applies sound wave in printing ink is to place like this piezo-electric crystal, utilizes piezo-electric crystal that the printing ink in the oil ink passage of nozzle back is discharged. Piezo-electric crystal should reach the total length of delegation's nozzle, thereby guarantees that all nozzles receive the sound wave of identical amplitude and phase place. Be applied to the size of size, shape, position and the ink storage device of physical characteristic that voltage magnitude on the piezo-electric crystal depends on crystal, nozzle, piezo-electric crystal is with respect to the displacement of printing ink nozzle and ink storage device, flow dynamic characteristic of printing ink etc. various factors. By attempting voltage magnitude and the phase place of different driving voltage, can obtain suitable drive waveforms with simple and cheap laboratory facilities, this means are more effective than calculating.

In the embodiment shown in Figure 20, the frequency of sound wave is 13.8KHz. This frequency is within the human audibility range, if a large amount of sound waves is sent in the air and passes to the outside of printer casing, will make the people feel bothersome high pitch whistle. Worried degree is people's subjective sensation, and varies with each individual. For example, only have a few peoples can feel the line frequency of 15.625 KHz of NTSC and PAL television transmission, and most people be can't hear sound. Problem to acoustic emission has several solutions. One of them is to guarantee that frequency of sound wave is higher than 20KHz, namely the highest audible frequencies of normal person. Another kind of scheme is with sound-absorbing material packet printing head assembly. This material only needs to absorb consumingly the fundamental frequency of sound wave, because second harmonic is more than 20KHz. Another scheme is to make the sound coupling of (by oil ink passage assembly and other elements) between printing ink and the air minimum in suitable frequency.

In near the separate type printer, regulate the ink droplet model

Figure 21 (a) expression proximity is separated printhead and is used for the sectional view of the pressing plate component of the defeated paper print system of reel.

Printhead 50 adopts digital tone to process six kinds of colors of printing for the panchromatic printing of high-quality, and (C C ' MM ' YK). Nearly 8mm is wide for printhead, and 600 μ m are thick. The distance of the position of printhead and recording medium 51 is DHtoP, and recording medium moves towards the direction of arrow 5 indications. Recording medium 51 is strained by pressing plate 67. Pressing plate 67 should have highly smooth optical flat, so that the friction of minimizing and recording medium, and in whole print area, keep positioning accuracy. Pressing plate can be used two or three pinch roller (not shown) instead and consist of, in order to further reduce friction. Can encase pinch roller with the conveyer belt (not shown), thus the positioning accuracy of the media 51 of holding the record. Pressing plate 67 is fixed on the piezoelectric ceramics 31 with a polaxis 33. Piezo-electric crystal is fixed on the plate 30, and plate 30 is that machinery is fixing with respect to printhead 50 during printing. Be provided with electrode 32 at piezo-electric crystal 31. Apply voltage at electrode 32, be used for adjustable range DHtop.

Printing ink 100 offers printhead by oil ink passage parts 75. Oil ink passage parts 75 also have the function that printhead is located rigidly, and proofread and correct the distortion in the printhead. Also can provide these functions by other devices. The power that drives heater is provided by two mains connections 38 and 39. Because connector can make with the metal material of hundreds of micron thickness, and connector can run through the total length of printhead, so just can provide large electric current to printhead, and voltage drop is very little. This point is very important, because color print head may be up to 20 amperes electric current when thousands of nozzles start simultaneously.

Under the pressure-acting that the plastic deformation material 35 that acts on the fixed block 34 provides, lateral paper guide is contact history media 51 lightly. Guide plate 36 has two functions: strain recording medium with defeated paper bobbin 65 at pressing plate, and temporary transient flattening may be from the outstanding fiber of the recording medium of paper one class. In order to improve print quality, need to flatten outstanding fiber, in order to reduce the change of distance that efficiency flat is arranged from the printhead to recording medium. Outstanding fiber is on the not significantly impact of size of print point, can be by reducing with the distance of nozzle and making it solve this problem near recording medium. This is fast like that when not having its infiltration sheet surperficial because of the speed that ink drop is infiltrated or absorbed along little outstanding fiber. Therefore, before ink drop was separated, the total ink of conveying can great changes have taken place. Guide plate 36 is not necessarily necessary, or can replace with the pulling force reel of reducing friction, and this depends on print speed, type recording media, and other factors of print system.

Small distance DHtoP between Figure 21 (b) expression printhead and the recording medium 51. In the moment that selected ink droplet contacts with recording medium, this distance is so that the volume of selected ink droplet 1 is very little. This distance B HtoP is by applying V at piezo-electric crystal_nomThe voltage of+Δ V obtains.

Nominal distance DHtoP between Figure 21 (c) expression printhead and the recording medium 51. In the moment that selected ink droplet contacts with recording medium, this is apart from the nominal volume that produces selected ink droplet 1. This distance B HtoP is by apply voltage V at piezo-electric crystal_nomObtain V wherein_nomIt is rated voltage. V_nomCan be zero, or a bias voltage, thereby can use the one pole regulation voltage need to obtain the gamut of adjusting. Δ V can be on the occasion of or negative value, depend on the orientation of crystal and the selection of electrode.

Figure 21 (d) represents distance B HtoP relatively large between printhead and the recording medium 51. In the moment that selected ink droplet contacts with recording medium, this distance is so that the volume of selected ink droplet 1 is relatively large. This distance B HtoP is by applying V at piezo-electric crystal_nomThe voltage of-Δ V obtains.

In the moment of contact history media, the printing ink volume that is transported on the recording medium is not equal to the volume of selecting ink droplet, because printing ink is to flow out continuously from nozzle when selected ink droplet infiltrates recording medium. Yet in certain opereating specification, the printing ink volume that is transported on the recording medium at Contact is proportional to the volume of selecting ink droplet substantially, and this opereating specification is by printing ink, and the characteristic of recording medium and nozzle is determined.

The another kind structure of this device is to adopt piezo-electric crystal to replace printhead with respect to the position of fixation clip, and vice versa. This structure has the function of equivalence, and comparing with said apparatus does not have obvious shortcoming, just during fabrication may be more difficult.

Might adopt the different piezo-electric crystal structure of many kinds, comprising the structure that makes crystal according to the cut mode operation, and the piezo-electric crystal structure that adopts multiple-layer overlapped, in order to reduce required control voltage. These changes are apparent to one skilled in the art, and are within the scope of the present invention.

Various overall and preferred embodiment of the present invention more than has been described. Under the condition that does not break away from the scope of the invention, those skilled in the art obviously can make amendment for above-mentioned overall and specific embodiment.

Claims (47)

1. throw in as required the printing equipment of ink drop, it is characterized in that comprising:

(a) has the printhead of many ink droplet nozzles;

(b) be connected to the printing ink feed line of said nozzle;

(c) pressure apparatus is used for applying the pressure that is higher than at least environmental pressure 2% to the printing ink of above-mentioned conduit;

(d) ink droplet selecting arrangement is used at the predetermined nozzle of ink droplet choice phase selective addressing, and at addressed nozzle with do not produce the alternate position spike of meniscus between the printing ink in the addressing nozzle, above-mentioned power is not enough so that the printing ink in the addressed nozzle separates; And

(e) ink droplet separator is used for making the printing ink of addressed nozzle be separated into ink droplet from the printing ink main body, allows simultaneously printing ink to be retained in the nozzle of not addressing.

2. install as defined in claim 1, it is characterized in that above-mentioned selecting arrangement makes the printing ink in the addressed nozzle move to selected position, cohesive force by printing ink is retained within the nozzle printing ink, but further more outstanding from nozzle than the printing ink in the addressing nozzle not, and above-mentioned ink droplet separator attracts this part further outstanding printing ink towards print area.

3. install as defined in claim 1, it is characterized in that above-mentioned ink droplet selecting arrangement utilizes electric heating to reduce the surface tension of pressurized printing ink.

4. install as defined in claim 1, it is characterized in that above-mentioned ink droplet selecting arrangement is an electric heating printing ink vapor bubbles generator, above-mentioned ink vapors bubble is not enough so that the printing ink main body of above-mentioned selected ink droplet from said nozzle separated.

5. install as defined in claim 1, it is characterized in that above-mentioned ink droplet selecting arrangement comprises the PZT (piezoelectric transducer) that direct or indirect Mechanical Contact is arranged with above-mentioned printing ink, and when driven, cause the change in volume of a printing ink cavity, this cavity is communicated with printing ink in the printing nozzle, and this change in volume is not enough so that the printing ink main body of above-mentioned selected ink droplet from said nozzle separated.

6. install as defined in claim 1, it is characterized in that above-mentioned ink droplet selecting arrangement comprises the device with the electrostatic attraction electrically conductive ink, its attraction is not enough so that the printing ink main body of this printing ink from said nozzle separated.

7. install as defined in claim 1, it is characterized in that above-mentioned ink droplet selecting arrangement comprises the printed medium that can move through in the following manner above-mentioned printhead, make selected ink droplet contact above-mentioned printed medium, and make unselected ink droplet not contact above-mentioned printed medium.

8. install as defined in claim 7, it is characterized in that the speed that above-mentioned selected ink droplet infiltrates and/or the speed on wetting above-mentioned printed medium surface is overflowed from addressed nozzle greater than printing ink.

9. device as defined in claim 8 is characterized in that ink pressure is that vibration by above-mentioned pressure apparatus obtains.

10. install as defined in claim 9, the frequency of oscillation that it is characterized in that ink pressure is the integral multiple of the drop ejection frequency in the nozzle.

11. device is characterized in that above-mentioned ink droplet separator comprises the device that attracts electrically conductive ink with static towards print area as defined in claim 1.

12. such as the device that claim 11 limits, it is characterized in that the electric field that consists of above-mentioned separator is applied on all nozzles substantially equably.

13. the device as claim 12 limits is characterized in that, because the position difference between above-mentioned selected ink droplet and the above-mentioned non-selected ink droplet, the electric power difference that selected ink droplet and non-selected ink droplet are subject to is very large.

14. device is characterized in that above-mentioned ink droplet separator comprises with the device of magnetic force towards print area attraction printing ink, comprises magnetisable material in printing ink as defined in claim 1.

15. such as the device that claim 14 limits, it is characterized in that the magnetic field that consists of above-mentioned separator is applied on all nozzles substantially equably.

16. the device as claim 14 limits is characterized in that, because the position difference between above-mentioned selected ink droplet and the above-mentioned non-selected ink droplet, the magnetic force difference that selected ink droplet and non-selected ink droplet are subject to is very large.

17. separate the method for selected ink droplet in printhead from the printing ink main body, said method may further comprise the steps:

(a) make above-mentioned selected ink droplet outstanding from an addressed nozzle of above-mentioned printhead; And

(b) make the position of printed medium or delivery roller fully near above-mentioned printhead, make above-mentioned selected ink droplet contact above-mentioned printed medium or delivery roller, but enough far away apart with above-mentioned printhead, make the printing ink that is not contained in the addressed nozzle can not contact above-mentioned printed medium or delivery roller.

18. a printer of throwing in as required is characterized in that comprising: (i) comprise the printhead of printing ink main body, (ii) make selected ink droplet from the outstanding device of above-mentioned print head surface; And

(iii) make the position of printed medium or delivery roller fully near above-mentioned printhead, make above-mentioned selected ink droplet contact above-mentioned printed medium or delivery roller, but enough far away apart with above-mentioned printhead, making also, the printing ink of non-selected ink droplet can not contact above-mentioned printed medium or delivery roller.

19. the print system that limits with claim 1 changes the method that is sent to the printing ink volume on the recording medium, it is characterized in that may further comprise the steps: (i) near on the position of above-mentioned printhead along print area moving recording media, and (ii) change distance between printhead and the above-mentioned recording medium.

20. be applicable to change the device of distance between printhead and the recording medium, said apparatus comprises a piezoelectric crystal unit, be used between above-mentioned printhead and above-mentioned media, realizing relative motion, and the device that voltage is provided to above-mentioned piezo-electric crystal, be used for changing the size of above-mentioned crystal, and change thus the distance between above-mentioned printhead and the above-mentioned media.

21. device as defined in claim 7 is characterized in that comprising be used to the device that changes distance between above-mentioned printhead and the recording medium.

22. be used for changing the device of distance between printhead and the recording medium, it is characterized in that comprising a piezo-electric crystal, one surface is by above-mentioned printhead, and another surface is supported on fixing position with respect to a pressing plate, and the device that is used for providing to above-mentioned piezo-electric crystal in the following manner voltage, thereby this voltage can make in the size that the direction that is substantially perpendicular to above-mentioned printhead front changes above-mentioned crystal above-mentioned printhead near and away from the recording medium between above-mentioned printhead and above-mentioned pressing plate.

23. the method that prints with ink droplet, printing ink main body in the printhead of the device that ink droplet wherein limits from claim 1, said method may further comprise the steps, printing ink main body in printhead applies sound wave, acoustic pressure is delivered on the printing ink in the nozzle addressed and not addressing, and from the addressed nozzle of above-mentioned printhead, separates ink droplet.

24. according to the method for claim 23, it is characterized in that above-mentioned frequency of sound wave is the integral multiple of the single-nozzle addressing frequency of above-mentioned printhead.

25. device is characterized in that above-mentioned pressure apparatus comprises a device as defined in claim 1, it applies sound wave to the printing ink main body in the above-mentioned conduit, and above-mentioned sound wave is provided for selected ink droplet and unselected ink droplet.

26. according to the device of claim 25, it is characterized in that above-mentioned Sonic wave sending device comprises:

(a) piezo-electric crystal that is communicated with above-mentioned printing ink main body, thereby the printing ink generation displacement when being subject to the electricity driving so that in the above-mentioned printing ink main body; And

(b) apply the device of oscillating voltage to above-mentioned piezo-electric crystal, the frequency of this voltage is the integral multiple of the drop ejection frequency of above-mentioned printhead.

27. the as required input printing equipment of fluid ink, said apparatus comprises:

(a) be used for to select the ink droplet selecting arrangement of printed dot, it is characterized in that above-mentioned ink droplet selecting arrangement produces the difference of meniscus position between the selected ink droplet of above-mentioned fluid ink and non-selected ink droplet;

(b) ink droplet separator, be used for attracting towards a substrate printing ink of above-mentioned ink droplet, above-mentioned attraction is not enough to overcome the ink droplet surface tension on the unselected meniscus position, but be enough to overcome the ink droplet surface tension on the selected meniscus position, thereby above-mentioned ink droplet is transferred on the above-mentioned substrate

Above-mentioned ink droplet selecting arrangement can produce the above-mentioned difference of meniscus position when not having above-mentioned ink droplet separator.

28. according to the device of claim 27, it is characterized in that above-mentioned ink droplet selecting arrangement utilizes electrical heating to reduce the surface tension of pressurized printing ink.

29. according to the device of claim 27, it is characterized in that above-mentioned ink droplet selecting arrangement is an electric heating printing ink vapor bubbles generator, above-mentioned ink vapors bubble is not enough so that the printing ink main body of above-mentioned selected ink droplet from said nozzle separated.

30. the device that limits such as claim 27, it is characterized in that above-mentioned ink droplet selecting arrangement drives one and with above-mentioned printing ink the PZT (piezoelectric transducer) of direct or indirect Mechanical Contact arranged, and when driven, cause the change in volume of a printing ink cavity, this cavity is communicated with printing ink in the printing nozzle, and this change in volume is not enough so that the printing ink main body of above-mentioned selected ink droplet from said nozzle separated.

31. such as the device that claim 27 limits, it is characterized in that above-mentioned ink droplet selecting arrangement electrostatic attraction electrically conductive ink, this electrostatic attraction is not enough so that the printing ink main body of above-mentioned selected ink droplet from said nozzle separated.

32. such as the device that claim 27 limits, it is characterized in that above-mentioned ink droplet selecting arrangement arranges printed medium in the following manner, make selected ink droplet contact above-mentioned printed medium, and make unselected ink droplet not contact above-mentioned printed medium.

33. such as the device that claim 32 limits, it is characterized in that the speed that above-mentioned selected ink droplet infiltrates and/or the speed on wetting above-mentioned printed medium surface is overflowed from printing nozzle greater than printing ink.

34. such as the device that claim 32 limits, it is characterized in that the ink pressure vibration.

35. such as the device that claim 32 limits, the frequency of oscillation that it is characterized in that ink pressure is the integral multiple of the drop ejection frequency in the nozzle.

36. such as the device that claim 27 limits, it is characterized in that comprising with static from the device that the printing ink main body is separated above-mentioned selected ink droplet attracting electrically conductive ink towards recording medium.

37. such as the device that claim 36 limits, it is characterized in that the electric field that produces above-mentioned electrostatic attraction is applied on all nozzles substantially equably.

38. the device as claim 36 limits is characterized in that, because the position difference between above-mentioned selected ink droplet and the above-mentioned non-selected ink droplet, the electric power difference that selected ink droplet and non-selected ink droplet are subject to is very large.

39. such as the device that claim 27 limits, it is characterized in that comprising with magnetic force from the device that the printing ink main body is separated above-mentioned selected ink droplet attracting printing ink towards recording medium, in printing ink, comprise magnetisable material.

40. such as the device that claim 39 limits, it is characterized in that the magnetic field that produces above-mentioned magnetic attraction is applied on all nozzles substantially equably.

41. the device as claim 39 limits is characterized in that, because the position difference between above-mentioned selected ink droplet and the above-mentioned non-selected ink droplet, the magnetic force difference that selected ink droplet and non-selected ink droplet are subject to is very large.

42. basically with reference to the aforesaid a kind of printing mechanism of throwing in as required of accompanying drawing.

43. with the device of throwing in as required mode printing-fluid printing ink, said apparatus comprises a printhead, this printhead comprises:

(a) many ink droplet nozzles;

(b) surface tension that the printing ink main body that interrelates with said nozzle, above-mentioned printing ink present in the temperature range more than 30 ℃ is at least by the Speed Reduction of 10mN/m;

(c) ink droplet selecting arrangement is used for selecting predetermined nozzle, and produces the difference of meniscus position between the printing ink in selected and unselected nozzle; And

(d) ink droplet separator is used for making the printing ink of selected nozzle to be separated into ink droplet from the printing ink main body, allows simultaneously printing ink to be retained in the unselected nozzle.

44. according to the device of claim 43, it is characterized in that above-mentioned ink droplet separator utilizes electric heating to reduce the surface tension of pressurized printing ink.

45. according to the device of claim 43, it is characterized in that above-mentioned ink droplet selecting arrangement is an electric heating printing ink vapor bubbles generator, above-mentioned ink vapors bubble is not enough so that the printing ink main body of above-mentioned selected ink droplet from said nozzle separated.

46. the device according to claim 43, it is characterized in that above-mentioned ink droplet selecting arrangement drives one and with above-mentioned printing ink the PZT (piezoelectric transducer) of direct or indirect Mechanical Contact arranged, and when driven, cause the change in volume of a printing ink cavity, this cavity is communicated with printing ink in the printing nozzle, and this change in volume is not enough so that the printing ink main body of above-mentioned selected ink droplet from said nozzle separated.

47. according to the device of claim 43, it is characterized in that above-mentioned ink droplet selecting arrangement electrostatic attraction electrically conductive ink, this electrostatic attraction is not enough so that the printing ink main body of above-mentioned selected ink droplet from said nozzle separated.

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