CN106457823A

CN106457823A - Inkjet head driving method and inkjet printing apparatus

Info

Publication number: CN106457823A
Application number: CN201580024427.8A
Authority: CN
Inventors: 小林谅平; 木泽亚纪子
Original assignee: Konica Minolta Opto Inc
Current assignee: Konica Minolta Inc; Konica Minolta Opto Inc
Priority date: 2014-03-31
Filing date: 2015-03-30
Publication date: 2017-02-22
Anticipated expiration: 2035-03-30
Also published as: JP6497384B2; EP3127705A4; WO2015152186A1; JPWO2015152186A1; EP3127705B1; CN106457823B; EP3127705A1

Abstract

The purpose of the present invention is to provide an inkjet head driving method and an inkjet printing apparatus that can suppress reduction of productivity while limiting occurrence of satellites and are capable of high quality image printing even when multiple droplets are discharged in a one-pixel period to form a large dot on the medium. The drive signal, when applying a discharging pressure on a liquid in a pressure chamber by applying the drive signal on a pressure-generating means to discharge droplets from a nozzle, comprises at least two kinds of drive signals, a first drive signal (PA) for discharging a droplet and a second drive signal (PB) for discharging a large droplet at a relatively slower speed than the first drive signal (PA). Pixels of dots obtained from droplets on a medium are formed by applying N of the second drive signals (PB) and applying the first drive signal (PA) at least at the end of a one-pixel period to discharge droplets from the same nozzle, and N is an integer of at least 1.

Description

The driving method of ink gun and ink-jet recording apparatus

Technical field

The present invention relates to the driving method of ink gun and ink-jet recording apparatus, specifically, even if being related to one kind at 1 Multiple drops are discharged in pixel period and the driving side that still is able to suppress to produce appendicular ink gun a little louder is formed on medium Method and ink-jet recording apparatus.

Background technology

Known following method：In the case of being formed a little louder on medium from the nozzle of ink gun discharge drop, at 1 From same nozzle, multiple drops are discharged in pixel period and so which is merged during circling in the air or overlappingly land on medium.Root According to the method, additionally it is possible to by selecting the number of drops that discharges in 1 pixel period deep or light to show, so being also used for performance Gray scale.

In the past, as the technology for discharging multiple drops in 1 pixel period from same nozzle, patent documentation 1～3 remembers The technology of load.

In patent documentation 1, before describing the final driving pulse for applying in 1 pixel period, according to gray scale During the initial driving pulse that applying is more than 1 time, the voltage value constant of each pulse is made, makes the application time ratio of initial driving pulse most Whole driving pulse length or short, so as to, while making each drop amount that is discharged by each pulse identical, make based on initial driving arteries and veins Liquid drop speed of the liquid drop speed ratio of punching based on final driving pulse is slow.

In patent documentation 2, the driving pulse for applying corresponding with gray scale more than 1 in 1 pixel period is described When, the voltage value constant of each driving pulse is made, in maximum greyscale waveforms and other greyscale waveforms, makes the defeated of final driving pulse Go out timing unanimously, and stopping period for predetermined distance is set between pixel period.

In patent documentation 3, describe and multiple discharge pulse signals are generated in 1 pixel period and for suppressing ink 1 auxiliary pulse signal of water meniscus vibration, according to gray scale, selects discharge pulse number.With regard to each discharge pulse Signal, voltage value constant, but discharge pulse signal below, the time interval of pulse is made gradually closer to actuator Natural period and elongated, so as to the drop that discharges afterwards, make liquid drop speed faster so that multiple drops merge in circling in the air.

In addition, in patent documentation 4, describing is including the such different drive signal of the 1st～the 3rd drive signal In a series of drive waveforms, the part of the 2nd drive signal is selected in 1 pixel period and discharges droplet, select the 1st, the 3rd The part of drive signal and drip in discharging, select the part of the 1st～the 3rd drive signal and discharge big drop, so as to carry out gray scale chart Existing.

Patent documentation 1：Japanese Unexamined Patent Publication 2007-118278 publication

Patent documentation 2：Japanese Unexamined Patent Publication 2008-93950 publication

Patent documentation 3：Japanese Unexamined Patent Publication 2001-146011 publication

Patent documentation 4：Japanese Unexamined Patent Publication 2007-105936 publication

Content of the invention

In the case of forming point as big as possible on medium, need when discharging multiple drops in 1 pixel period Substantial amounts of drop as big as possible is discharged from same nozzle in 1 pixel period.

But, drop amount is bigger, or liquid drop speed is faster in the case that drop amount is big, then appendicular generation is more made It is a problem.Appurtenance is referred in the little drop (spittle) for discharging the dependency formation of drop (main drop) Shi Qi behind from nozzle, It is likely to result in the reduction of image quality.

In patent documentation 1,3, the drop amount phase of multiple drops that discharges in 1 pixel period is made from same nozzle With.Therefore, if little drop is continuously discharged, that is, allow to suppress appurtenance, still suffer from following problem：Big in order to be formed Point, needs to discharge substantial amounts of drop in 1 pixel period, and productivity ratio reduces.In addition, in the feelings for continuously discharging big drop Under condition, the drop that finally discharges is also big drop, so existing due to the final drop that discharges and producing appendicular asking in a large number Topic.

In patent documentation 2, although seek to reduce by during arranging the stopping of predetermined distance between pixel period The impact of residual oscillation, but be still not enough to suppression and produce appurtenance.

In addition, in patent documentation 4, not referring to any with regard to the appendicular content of suppression generation.

Present inventor concentrates on studies and discharges multiple drops and form point as big as possible on medium in 1 pixel period Method, as a result find by combining relatively large drop and relatively small drop and studying the pass of their liquid drop speed System and the timing of relatively small drop being discharged, big point can be formed on medium and also can suppress to produce appurtenance, Complete the present invention.

In addition, when the number of drops change that make to discharge in 1 pixel period is come in the case of carrying out expressing gradation, similarly Ground finds to suppress to produce appurtenance, completes the present invention.

Even if that is, the problem of the present invention be provide one kind discharge multiple drops in 1 pixel period and on medium Formed a little bigger, it is also possible to which while suppressing productivity ratio to reduce, suppression produces appurtenance and can carry out the image note of high-quality The driving method of the ink gun of record and ink-jet recording apparatus.

In addition, the problem of the present invention is to provide a kind of number of drops change by making discharge in 1 pixel period During expressing gradation is carried out, suppression can produce appurtenance and high-quality can be carried out while suppressing productivity ratio to reduce The driving method of the ink gun of image record and ink-jet recording apparatus.

Other problems of the present invention are will be apparent from by following record.

At least one of to achieve these goals, reflect the driving method of the ink gun of one aspect of the present invention With following structure.

A kind of driving method of ink gun, be by pressure generating unit apply drive signal and to the liquid in pressure room Body gives the driving method of the ink gun for making that for the pressure that discharges drop is discharged from nozzle,

The drive signal includes at least following 2 kinds of drive signals：Discharge the 1st drive signal of drop and with the described 1st Drive signal discharges the 2nd drive signal of big drop with comparing relative low speeds,

By applying N number of 2nd drive signal in 1 pixel period, at least finally applying the described 1st driving letter Number, so that drop is discharged from the same nozzle, the pixel based on the point being made up of the drop is formed on medium, and And, the N is more than 1 integer.

At least one of to achieve these goals, reflect the driving of other ink guns of one aspect of the present invention Method has following structure.

A kind of driving method of ink gun, be by pressure generating unit apply drive signal and to the liquid in pressure room Body gives the driving method of the ink gun for making that for the pressure that discharges drop is discharged from nozzle, it is characterised in that

By applying N number of 2nd drive signal in 1 pixel period, at least finally applying the described 1st driving letter Number, so that drop is discharged from the same nozzle, the pixel based on the point being made up of the drop is formed on medium, and And, according to view data, make the N change by more than 0 integer and point of different sizes is made on medium, carry out gray scale chart Existing.

At least one of to achieve these goals, the ink-jet recording apparatus for reflecting one aspect of the present invention have Following structure.

A kind of ink-jet recording apparatus, possess：

Ink gun, gives the pressure for discharging by the driving of pressure generating unit, makes liquid to the liquid in pressure room Drop is discharged from nozzle；And

Drive control unit, the drive signal of pressure generating unit described in output driving,

The drive control unit passes through to apply N number of 2nd drive signal in 1 pixel period, at least last Apply the 1st drive signal, so that drop is discharged from the same nozzle, formed on medium and be based on by the drop structure The pixel of the point for becoming, also, the N is more than 1 integer.

At least one of to achieve these goals, reflect other ink-jet recording apparatus of one aspect of the present invention With following structure.

A kind of ink-jet recording apparatus, possess：

The drive control unit passes through to apply N number of 2nd drive signal in 1 pixel period, at least last Apply the 1st drive signal, so that drop is discharged from the same nozzle, formed on medium and be based on by the drop structure The pixel of the point for becoming, also, according to view data, so that the N is changed by more than 0 integer and make on medium of different sizes Point, carry out expressing gradation.

Description of the drawings

Fig. 1 is the summary construction diagram of an example of the ink-jet recording apparatus for illustrating the present invention.

Fig. 2 is the figure of an example for illustrating ink gun, and (a) is the axonometric chart for illustrating outward appearance with section, (b) be from side The profile of observation.

Fig. 3 is the figure of an example of the driving method that the ink gun in the present invention is described.

Fig. 4 (a) is the figure of the example that the 1st drive signal is described, (b) is the example that the 2nd drive signal is described Figure.

Fig. 5 (a)～(c) is the figure of the discharging operation that ink gun is described.

Fig. 6 (a) is the concept map of the drop that is discharged by the 1st drive signal, and (b) is arranged by the 2nd drive signal The concept map of the drop for going out.

Fig. 7 (a) is the figure of another example that the 1st drive signal is described, (b) is another example that the 2nd drive signal is described Figure

Fig. 8 (a) is the figure of an example of the state of circling in the air that drop is described, (b) is to illustrate therefrom to be formed on medium Point figure.

Fig. 9 (a) is the figure of another example of the state of circling in the air that drop is described, (b) is to illustrate therefrom to be formed on medium Point figure.

Figure 10 (a) is the figure of yet another example of the state of circling in the air that drop is described, (b) is to illustrate shape on medium therefrom The figure of the point for becoming.

Figure 11 is an example of the driving method for illustrating to carry out in the present invention the ink gun in the case of expressing gradation Figure.

Figure 12 (a) is an example for illustrating only to apply the driving method of the 2nd drive signal in 1 pixel period Figure, (b) is the figure of the example that explanation makes the different driving method of the timing of the 1st drive signal in Fig. 3.

(symbol description)

1：Ink-jet recording apparatus；2：Conveying mechanism；21：Conveying roller；22：Conveying roller pair；23：Conveying motor；3：Ink gun； 30：Channel substrate；31：Passage；32：Next door；321：Upper wall portions；322：Lower wall portion；33：Lid substrate；331：Common flow path；34： Nozzle plate；341：Nozzle；35：Plate；351：Ink supply port；352：Ink supply conduit；4：Guide rail；5：Balladeur train；6：Flexible cable； 7：Medium；71：Recording surface；8：Drive control part；100：Drop；200：Drop；201：Little liquid ball；202：Big liquid ball；D：Point； PA：1st drive signal；Pa1：Expansion pulse；Pa2：Shrink pulse；PWA1、PWA2：Pulse width；PWA3：During stopping；PB： 2nd drive signal；Pb1：1st expansion pulse；Pb2：1st shrinks pulse；Pb3：2nd expansion pulse；Pb4：2nd shrinks pulse； PWB1～PWB4：Pulse width；T：Pixel period；TA：The drive cycle of the 1st drive signal；TB：The driving of the 2nd drive signal Cycle T 1, T2：During stopping.

Specific embodiment

In ink-jet recording apparatus 1, conveying mechanism 2 includes the medium of paper, plastic sheet, cloth etc. by conveying roller to 22 clampings 7, the rotation of the conveying roller 21 for carrying out by using conveying motor 23 is conveyed to the Y-direction (sub-scanning direction) of in figure.In conveying Roller 21 and conveying roller are between 22, being provided with ink gun (hereinafter referred to as head) 3.3 so that the record of nozzle surface side and medium 7 The facing mode in face 71 is equipped on balladeur train 5, via flexible cable 6, the drive with the drive control unit for constituting in the present invention Dynamic control unit 8 is electrically connected.

Balladeur train 5 is arranged to by driver element (not shown), and set up along in the range of the width in medium 7 leads Rail 4, the X-X ' direction (main scanning direction) of the in figure being substantially orthogonal in the sub-scanning direction with the conveying direction as medium 7 On can reciprocate.3 with reciprocating for balladeur train 5, the recording surface 71 in medium 7 is moved on main scanning direction, During the movement, according to view data, drop is discharged from nozzle and record ink jet image.

Fig. 2 is the figure of an example for illustrating 3, and (a) is the axonometric chart for illustrating outward appearance with section, and (b) is seen from side The profile that examines.

In 3,30 is channel substrate.In channel substrate 30, many of stria shape are disposed with an alternating fashion Individual passage 31 and next door 32.On the upper surface of channel substrate 30, in the way of blocking the top of all passages 31, lid is provided with Substrate 33.End joined nozzle plate 34 to channel substrate 30 and lid substrate 33.One end of each passage 31 is through being formed from the spray The nozzle 341 of mouth plate 34 and ft connection.

The other end of each passage 31 is formed to gradually become shallow slot with respect to channel substrate 30.Shape in lid substrate 33 Become the common flow path 331 common for each passage 31.The common flow path 331 is connected with each passage 31.Common flow path 331 is by plate 35 Blocking.Ink supply port 351 is formed with plate 35.Via the ink supply port 351, from ink supply conduit 352 to common stream Supply ink in road 331 and each passage 31.

Next door 32 is made up of piezoelectric elements such as the PZT as electrical/mechanical converter unit.With regard to the next door 32, exemplified with The example for being formed by mutually opposite direction upper wall portions 321 and lower wall portion 322 are carried out with the piezoelectric element of polarization process. But, in next door 32, such as upper wall portions 321 may also be only by the part that piezoelectric element is formed.It is alternately arranged setting next door 32 and passage 31, so 1 next door 32 is shared by the passage 31,31 of its two neighbour.

In the inner surface of passage 31, from the wall in two next doors 32,32 to bottom surface, drive electrode is respectively formed with (in Fig. 2 In not shown).When the drive signal for applying assigned voltage from 8 pairs of 2 drive electrodes for clipping the configuration of next door 32 of drive control part When, there is detrusion with the composition surface of upper wall portions 321 and lower wall portion 322 as boundary in next door 32.When 2 adjacent next doors 32, 32 to during the generation detrusion of mutual rightabout, and the volume of the passage 31 for being clipped by the next door 32,32 is expanded or received Contracting, internally produces pressure wave.Thus, the pressure for discharging is given to the ink in passage 31.

This 3 is by next door 32, detrusion occurs and make the shearing mould that the ink in passage 31 discharged from nozzle 341 The head of formula type, is preferred pattern in the present invention.By leading to that channel substrate 30, next door 32, lid substrate 33, nozzle plate 34 are surrounded Road 31 is an example of the pressure chamber in the present invention, and the drive electrode on next door 32 and its surface is the pressure generation in the present invention One example of unit.

Drive control part 8 can discharge multiple drops from same nozzle 341 in 1 pixel period, it is possible at 1 Multiple drive signals are generated in pixel period.By the drive signal for being generated output to the end 3, and it is applied to and is formed at next door 32 Each drive electrode.Additionally, 1 pixel period is referred to for forming base on medium by making the drop land that discharges from nozzle Time interval in each pixel of point.

Fig. 3 be illustrate in the present invention for by apply multiple drive signals in 1 pixel period and in medium 7 Form the figure of an example of a little bigger driving method.Here, exemplified with to the spray with discharge drop in 1 pixel period T Multiple drive signals that the drive electrode of 341 corresponding passage 31 of mouth applies.

Multiple drive signals in the present invention include at least following 2 kinds of drive signals：1st drive signal PA and the 2nd drives Signal PB.1st drive signal PA and the 2nd drive signal PB are the speed letters different with drop amount of the drop that is discharged accordingly Number.The drop that is discharged by the 2nd drive signal PB is relatively low compared to the drop that is discharged by the 1st drive signal PA Speed, also, drop amount is larger.

Additionally, the liquid drop speed in the present invention is to carry out image recognition to drop by using drop observation device and obtain From discharge elapsed time and now drop presence position coordinateses and calculate.Specifically, be according to drop from leaving The distance that the position that 500 μm of nozzle face is circled in the air during 50 μ s is calculated.Elapsed time from discharging can pass through Make ink gun discharge signal and observation with stroboscope synchronously calculating.In addition, the position coordinateses of drop can be by flying Xiang image carries out image procossing to calculate.

According to the driving method for forming the ink gun in a little bigger present invention, by applying in 1 pixel period T N number of 2nd drive signal PB and 1 pixel period T at least finally apply the 1st drive signal PA, from same nozzle 341 discharge multiple drops.Now, by N is set to more than 1 integer, the point on medium 7 by being made up of the plurality of drop And form pixel.The multiple drops that discharges from same nozzle 341 in 1 pixel period T pass through to merge during circling in the air, Neng Gou On medium 7, pixel is formed by the point that is made up of the drop of 1 zoarium.In addition it is possible to make multiple drops to overlap Mode land on medium 7, pixel is formed by the point that is made up of the aggregation of multiple points.

2nd drive signal PB is the driving letter for discharging the drop relatively large compared to drop based on the 1st drive signal PA Number, so by applying more than 1 signal in 1 pixel period T, mainly helpful a little louder to being formed.In addition, being based on The drop of the 2nd drive signal PB is relative low speeds compared to the drop based on the 1st drive signal PA, produced appurtenance by The drop that discharges after in same pixel period T catches, so not resulting in the problem of the degree for reducing image quality.

In the case of multiple drops are discharged in 1 pixel period T, the appurtenance of leading drop is by same pixel The drop that discharges after in cycle T catches, so according to the viewpoint of image quality, the liquid of the last discharge in 1 pixel period T Drip incidental appurtenance especially to throw into question.According to the present invention, must finally apply the 1st driving in 1 pixel period T Signal PA, thus, discharges the drop relatively small compared to drop based on the 2nd drive signal PB, thus do not produce appurtenance or Person's appurtenance is suppressed.

Even if passing through to apply the 1st drive signal PA and the 2nd drive signal in 1 pixel period T therefore, it is possible to provide PB is formed a little bigger discharging multiple drops on medium 7, it is also possible to which while suppressing productivity ratio to reduce, suppression produces attached Thing simultaneously can carry out the driving method of ink gun 3 of image record and the ink-jet recording apparatus 1 of high-quality.

In figure 3, TA is the drive cycle of the 1st drive signal PA in 1 pixel period T, and TB is 1 pixel period T The drive cycle of the 2nd interior drive signal PB.Here, exemplified with 1 pixel period T with follow-up drive signal it Between be separated out regulation the mode of the period T1 that stops apply 3 (N=3) the 2nd drive signal PB and from last 1 the 1st for applying Be separated out regulation during the beginning of the applying end to ensuing 1 pixel period T of drive signal PA stops period T2's Example.

In addition, number N of the 2nd drive signal PB is more than 1 integer, 3 for illustrating are not limited to, however, N is more than 1 Which value, last in 1 pixel period T must all apply the 1st drive signal PA.Therefore, no matter which of more than 1 N be One value, all appurtenance suppressed as described above.No matter additionally, although it is not shown, N is more than 1 which value, finally applying 1st drive signal PA is applied in the way of becoming the same timing in 1 pixel period T.

Next, Fig. 4 is used, the concrete structure of the 1st drive signal PA and the 2nd drive signal PB is described.Fig. 4 (a) shows The 1st drive signal PA is gone out, (b) shows the 2nd drive signal PB.But, drive signal PA, the PB shown in Fig. 4 is the present invention In a preferred example, not by example illustrated any restriction.

First, the structure of the 1st drive signal PA is described.

1st drive signal PA has expansion pulse Pa1 for making the cubical expansion of passage 31 and shrinking after some time And make the volume contraction of passage 31 the contraction pulse Pa2 for expanding after some time.

In the example shown in Fig. 4 (a), expansion pulse Pa1 is to rise from reference potential and decline after some time Pulse to reference potential.In addition, it is to decline and rise to after some time benchmark electricity from reference potential to shrink pulse Pa2 The pulse of position.Additionally, reference potential is set to 0 current potential by here, but it is not particularly limited.

The driving voltage value (- Voff) of the driving voltage value (+Von) of expansion pulse Pa1 and contraction pulse Pa2 is set For | Von |:| Voff |=2:1.

In the example of the 1st drive signal PA, expansion pulse Pa1 trailing edge terminal with shrink pulse Pa2 Between the top of trailing edge, the period PWA3 that stops that reference potential is maintained certain period is provided with.Its object is to, it is to avoid base In the relation with aftermentioned 2nd drive signal PB, the volume of passage 31 is once changed to from the swelling state based on expansion pulse Pa1 Based on the contraction state for shrinking pulse Pa2, become too fast so as to liquid drop speed, and avoid the drop quantitative change of discharged drop Too much.By adjusting the length of the period PWA3 that stops, can based on the liquid that is discharged according to aftermentioned 2nd drive signal PB The relation of drop, is easily adjusted speed and the drop amount of the drop that discharges by the applying of the 1st drive signal PA.Therefore, The period PWA3 that stops is preferably provided with the 1st drive signal PA.

Additionally, in the present invention, at least must finally apply 1 the 1st drive signal PA i.e. in 1 pixel period T Can.Therefore, before the 1st drive signal PA of last applying of the complete without prejudice in 1 pixel period T, except the 2nd drives letter Also apply the 1st drive signal PA of more than 1 beyond number PB.At this time, it is also possible to initially applying in 1 pixel period T sometimes Plus the 1st drive signal PA, but in this case, for example, it is preferable to by by during the stopping of initial the 1st drive signal PA for applying The period PWA3 that stops that PWA3 is set to the 1st drive signal PA than finally applying is long, becomes the speed of the drop of initial discharge Slowly improving land.

In addition, the 1st drive signal PA is preferably the multiple drivings letter for being arranged in 1 pixel period T in temporal sequence The drive signal for forming the drop of minimum in number.Thereby, it is possible to improve the appendicular effect of suppression further, and also Landing positions can be suppressed to offset.

Further, according to the viewpoint of the inhibition for improving appendicular inhibition and landing positions skew further, 1st drive signal PA be preferably in multiple drive signals for being arranged in 1 pixel period T in temporal sequence for forming liquid The drive signal of the minimum and fast drop of liquid drop speed of drop.

The preferably rectangular ripple of 1st drive signal PA.That is, as shown in the figure expansion pulse Pa1 and shrink pulse Pa2 all by square Shape ripple is constituted.3 of shear mode-type described in present embodiment being capable of applying with respect to the drive signal being made up of square wave Plus make phase place as one man produce pressure wave, it is possible to efficiently discharging drop, and driving voltage can be suppressed lower. No matter general discharge, do not discharge, all correct 3 applied voltages all the time, so in order to suppress 3 heating and penetrate with making droplets stable Go out, low driving voltage is important.

In addition, square wave can be easily produced using simple digital circuit, so compared to using with inclination The situation of the trapezoidal wave of ripple, additionally it is possible to simplify circuit structure.

Pulse width PWA1 of expansion pulse Pa1 is preferably more than 0.8AL and below 1.2AL, shrinks the pulse of pulse Pa2 Width PWA2 is preferably more than 1.8AL and below 2.2AL.Thereby, it is possible to efficiently discharge drop.In addition, if during stopping PWA3 becomes long, then be difficult to discharge the fast drop of drop of the drop speed ratio based on the 2nd drive signal PB, also, discharge effect Rate is greatly reduced, it is advantageous to being adjusted in below 1/4AL.

It is the abbreviation of Acoustic Length (sound path) in this AL, is the acoustic resonance cycle of the pressure wave in passage 31 1/2.With regard to AL, the speed of circling in the air of the drop that discharges when the drive signal of square wave is applied to drive electrode is determined, is obtained It is the pulse width of the speed maximum of circling in the air of drop when the voltage value constant for making square wave makes the pulse width variation of square wave Degree.

In addition, pulse refers to the square wave of constant voltage peak value, 0V is being set to 0%, crest voltage is being set to 100% In the case of, pulse width is defined as between the rising edge 10% from the 0V of voltage and the trailing edge from crest voltage 10% Time.

Further, square wave refers to that rising time between the 10% of voltage and 90%, trailing edge time are all the 1/2 of AL Within, such waveform within preferably 1/4.

Next, the structure of the 2nd drive signal PB of explanation.

Used as the example of the 2nd drive signal PB, having successively makes the cubical expansion of passage 31 and receives after some time 1st expansion pulse Pb1 of contracting, make the volume contraction of passage 31 and expand after some time the 1st contraction pulse Pb2, make The cubical expansion of passage 31 the 2nd expansion pulse Pb3 that shrinks after some time and make passage 31 volume contraction simultaneously The 2nd contraction pulse Pb4 for expanding after some time.

In the example shown in Fig. 4 (b), the 1st expansion pulse Pb1 be from reference potential rise and after some time It is down to the pulse of reference potential.1st contraction pulse Pb2 is to decline and rise to after some time benchmark electricity from reference potential The pulse of position.2nd expansion pulse Pb3 is to rise and drop to after some time the pulse of reference potential from reference potential. 2nd contraction pulse Pb4 is the pulse for declining and rising to after some time reference potential from reference potential.Additionally, here Also reference potential is set to 0 current potential, but is not particularly limited.

The driving voltage value (+Von) of the 1st expansion pulse Pb1 and the 2nd expansion pulse Pb3 and the 1st shrink pulse Pb2 with And the 2nd contraction pulse Pb4 driving voltage value (- Voff) be set to | Von |:| Voff |=2:1.

1st contraction pulse Pb2 is not separated out under stopping period ground continuously from the terminal of the trailing edge of the 1st expansion pulse Pb1 Drop.In addition, the 2nd expansion pulse Pb3 is not separated out on continuous during stopping from the terminal of the rising edge of the 1st contraction pulse Pb2 Rise.Further, under during the 2nd contraction pulse Pb4 is not separated out from the terminal of the trailing edge of the 2nd expansion pulse Pb3 and stops, ground is continuous Drop.

2nd drive signal PB also according to same with the 1st drive signal PA the reasons why preferably rectangular ripple.As illustrated, 1st expansion pulse Pb1, the 1st contraction pulse Pb2, the 2nd expansion pulse Pb3 and the 2nd contraction pulse Pb4 are made up of square wave.

Pulse width PWB1 of the 1st expansion pulse Pb1 in the 2nd drive signal PB be preferably more than 0.4AL and 2.0AL with Under, the 1st pulse width PWB2 for shrinking pulse Pb2 is preferably more than 0.4AL and below 0.7AL, the arteries and veins of the 2nd expansion pulse Pb3 Rush width PWB3 and more than 0.8AL and below 1.2AL is preferably, pulse width PWB4 of the 2nd contraction pulse Pb4 is preferably 1.8AL Above and below 2.2AL.Thereby, it is possible to discharge big drop with short drive cycle, and liquid drop speed is also suppressed.Cause This, can discharge the big drop of drop amount compared to the drop relative low speeds based on the 1st drive signal PA.

In addition, according to the viewpoint for reducing the appendicular impact for existing between multiple drops, the period T1 that stops is preferably Below 2AL, the impact of the pressure wave reverberation vibration in the passage 31 after being discharged according to suppression drop simultaneously arranges follow-up drop Go out stabilized viewpoint, the period T2 that stops is preferably more than 1.5AL.

Next, Fig. 5 is used, 3 when applying the 1st drive signal PA and the 2nd drive signal PB shown in Fig. 4 are described Discharging operation.Fig. 5 shows of a cut-out section obtained from 3 on the direction orthogonal with the length direction of passage 31 Point.Here, the passage 31B for being set to the central authorities from Fig. 5 discharges drop.In addition, Fig. 6 be shown in applying the 1st drive signal PA with And the concept map of the drop that discharges during the 2nd drive signal PB.

First, the discharging operation based on the 1st drive signal PA is described.

As shown in Fig. 5 (a), in drive electrode 36A, 36B, the 36C in mutually adjacent passage 31A, 31B, 31C When any one does not apply drive signal, next door 32A, 32B, 32C, 32D become indeformable neutral condition.In addition, work as will When drive electrode 36A and 36C is grounded and applies expansion pulse Pa1 in the 1st drive signal PA to drive electrode 36B, produce The electric field in the raw direction vertical with the polarised direction of the piezoelectric element for constituting next door 32B, 32C.Thus, next door 32B, 32C such as Fig. 5 Mutually occur bending and deformation laterally shown in (b), the cubical expansion (Draw) of passage 31B.Thus, produce in passage 31B negative Pressure, ink flow into.

Press pin in passage 31B is inverted to every 1AL, if so by expansion pulse Pa1 maintain more than 0.8AL and During below 1.2AL, then positive pressure is reversed in passage 31B.When the applying for regularly terminating expansion pulse Pa1 at this is returned When being back to reference potential, next door 32B, 32C return to the neutral condition (Release) shown in Fig. 5 (a).Now, to passage 31B Interior ink applies big pressure, and ink is to the direction movement being forced out from nozzle 341.

When applying to shrink pulse Pa2 to drive electrode 36B after neutral condition to be maintained the period PWA3 that stops, every Wall 32B, 32C are mutually occured bending and deformation to inner side as shown in Fig. 5 (c), the volume contraction (Reinforce) of passage 31B.Its knot Really, the ink in passage 31B is further pressed on, is entered one to the ink that the direction being forced out from nozzle 341 moves Step is extruded.Afterwards, the ink being forced out is crushed, and such as discharges 1 drop 100 shown in Fig. 6 (a).

The drop 100 is the little droplet of drop of the drop amount ratio based on aftermentioned 2nd drive signal PB.Discharging drop When 100, do not produce appurtenance, even if or produce also be suppressed to very small amount.

Based on the contraction state of pulse Pa2 is shunk after it have passed through more than 1.8A and below 2.2AL, in passage 31B Pressure transition return to original state for timing.Thus, next door 32B, 32C returns to the neutral condition of Fig. 5 (a).

Next, discharging operation of the explanation based on the 2nd drive signal PB.

If be grounded drive electrode 36A and 36C from the neutral condition shown in Fig. 5 (a), and to drive electrode 36B applies the 1st expansion pulse Pb1 in the 2nd drive signal PB, then next door 32B, 32C is mutually sent out as shown in Fig. 5 (b) laterally Raw flexural deformation, the cubical expansion of passage 31B.Thus, negative pressure is produced in passage 31B, and ink is flowed into.

After the 1st expansion pulse Pb1 maintains more than 0.4AL and below 2.0AL, the applying knot of the 1st expansion pulse Pb1 Bundle.Thus, next door 32B, 32C shrinks from swelling state and returns to neutral condition.Then, when be not separated out stop during and then Apply the 1st contraction pulse Pb2, next door 32B, 32C are immediately turned into the contraction state shown in Fig. 5 (c) via neutral condition.Now, Pressure is applied to the ink in passage 31B, ink is extruded from nozzle 341 and is discharged as the 1st drop.

1st contraction pulse Pb2 is maintained more than 0.4AL and below 0.7AL.Then, when be not separated out stop during and then When applying 2 expansion pulse Pb3, next door 32B, 32C are expanded from contraction state, are immediately turned into shown in Fig. 5 (b) via neutral condition Swelling state, produce negative pressure in passage 31.Therefore, the speed of the 1st drop that discharges before is suppressed.In addition, Thus in passage 31B, negative pressure is produced, ink is again flowed into.

With regard to the 2nd expansion pulse Pb3, after more than 0.8AL and below 1.2AL is maintained, just it is changed in passage 31B Pressure when, apply to terminate.Then, when be not separated out stop during and then apply the 2nd contraction pulse Pb4 when, next door 32B, 32C Shrink from swelling state, the contraction state being immediately turned into via neutral condition shown in Fig. 5 (c).Now, to the ink in passage 31B Water applies big pressure, then passes through the 1st expansion pulse Pb1 and the 1st and shrinks the 1st drop that pulse Pb2 is discharged, further Ground is a large amount of to extrude ink, and the ink being forced out is crushed immediately and discharges the 2nd big drop of liquid drop speed.

With regard to the drop that discharges by the 2nd drive signal PB, shown in such as Fig. 6 (b), the 1st expansion pulse Pb1 is then passed through And the 1st shrink the 1st little the 1st drop 201 of liquid drop speed that pulse Pb2 discharges, formed by the 2nd expansion pulse Pb3 with And the 2nd shrink the 2nd big the 2nd drop 202 of liquid drop speed that pulse Pb4 discharges.Therefore, discharging originally, forming the 1st liquid Drop 202 connected drop 200 of the 201 and the 2nd drop.One in 1st drop 201 and the 2nd drop 202 circling in the air after just discharging Body and form 1 big drop 200.

The big big drop of drop 100 that the drop 200 is discharged by the 1st drive signal PA for drop amount ratio.But, by Zoarium is carried out in the 2nd big drop 202 of the 1st little drop 201 of liquid drop speed and liquid drop speed, so compared to from nozzle 341 The situation of 1 big drop of identical drop amount is discharged, liquid drop speed is slack-off, according to present embodiment, speed ratio is driven by the 1st Dynamic signal PA and the drop 100 discharged is low.Now, the liquid drop speed of the drop 100 that is discharged by the 1st drive signal PA is preferred It is adjusted to less than the liquid drop speed of the 2nd drop 202.The appurtenance amount of drop 200 depends on the liquid drop speed of the 2nd drop 202, leads to Cross and the liquid drop speed of drop 100 is adjusted to less than the liquid drop speed of the 2nd drop 202 based on the 2nd drive signal PB, can press down The appurtenance amount of drop processed 100.

Additionally, the liquid drop speed of the drop 200 that is discharged by the 2nd drive signal PB is the 1st drop 201 and the 2nd drop The liquid drop speed of 202 states being integrally formed.

The contraction state of pulse Pb4 is shunk after it have passed through more than 1.8AL and below 2.2AL based on the 2nd, in passage Pressure transition in 31B returns to original state for timing.Thus, next door 32B, 32C is expanded from contraction state, in returning to Vertical state.

Driving method according to Fig. 3, in 1 pixel period T, is initially applied continuously in 3 the 2nd drive signals PB, so as to discharge 3 big drops 200 from same nozzle 341, then finally applies 1 the 1st drive signal PA, so as to discharge 1 Individual drop 100, so form pixel by the point that is made up of 4 drops on medium 7.

In the present embodiment, it is contemplated to discharge the drop 100 of 6pl (picoliters) by the 1st drive signal PA, by the 2 drive signal PB and discharge the example of the drop 200 of 10pl.Therefore, in figure 3, can be in 1 pixel period T, in medium The big point being made up of the drop of total 36pl is formed on 7.

If it is assumed that only continuously the 1st drive signal PA is applied 4, even if then appurtenance is suppressed, it is only able to be formed The point being made up of the drop of total 24pl.In addition, the point for constituting for the drop for being formed by 36pl, needs in 1 pixel period T 6 the 1st drive signal PA of interior continuous applying, so productivity ratio reduces.In addition, being only applied continuously in the 2nd drive signal PB's In the case of, as the last drop that discharges is also big drop, so worry produces appurtenance.But, as the present invention, 1 Apply the 2nd drive signal PB of more than 1 in individual pixel period T, arranged in 1 pixel period T in temporal sequence is many Finally the 1st drive signal PA must be applied in individual drive signal, thereby while can be formed on medium 7 a little bigger, but finally The drop 100 being made up of minimum drop must be discharged, so while suppressing productivity ratio to reduce, also suppression produces attached Thing.

In addition, in general, by using by the DRR (Draw-Release- same with the 1st drive signal PA Reinforce) waveform constitute drive signal and extend its pulse width, it is also possible to discharge big drop.But, in the situation Under, become macrocyclic drive signal, so substantial amounts of drop cannot be discharged within the limited time in 1 pixel period T. But, the 2nd drive signal PB can be with the big drop 200 of short cycle discharge relative low speeds, it is possible to 1 pixel week In the limited time in phase T, more drops are discharged, the pixel being made up of big point correspondingly can be formed on medium 7.

Additionally, the deformation in next door 32 is due to the electricity between 2 drive electrodes being arranged in the way of clipping the next door 32 Pressure reduction and cause.Therefore, in the case of being discharged from the passage 31B shown in Fig. 5 by the 1st drive signal PA, such as Fig. 7 Shown in (a), even if apply expansion pulse Pa1 of+Von to the drive electrode 36B in the passage 31B as passing away, to neighbour Drive electrode 36A, 36C of passage 31A, 31C for connecing applies the contraction pulse Pa2 of+Voff, it is also possible to similarly drive.

In addition, similarly, in the case of being discharged from the passage 31B shown in Fig. 5 by the 2nd drive signal PB, such as Shown in Fig. 7 (b), even if apply the 1st expansion pulse of+Von to the drive electrode 36B in the passage 31B as passing away Pb1, the 2nd expansion pulse Pb3, drive electrode 36A, 36C of passage 31A, 31C to adjoining apply the 1st contraction pulse of+Voff Pulse Pb4 is shunk in Pb2, the 2nd, it is also possible to similarly drive.

In the case of using the 1st drive signal PA shown in Fig. 7 (a), (b) and the 2nd drive signal PB, only can lead to Cross positive voltage and each drive signal is constituted, it is possible to simplifying the structure of drive control part 8.

In the present invention, the diameter of the drop 100 that is discharged by the 1st drive signal PA is preferably than the diameter of nozzle 341 Little.The drop 100 less than the diameter of nozzle 341 by being set to diameter, can improve appurtenance inhibition further.

Here, with regard to the diameter of nozzle, in the case that the shape of the opening of the discharge direction front end of nozzle is circle, being Refer to its diameter, in the case of being not circle, refer to be replaced into the diameter of a circle in the case that aperture area identical is justified.

In addition, with regard to the diameter of drop, in the case that drop is spherical, referring to its diameter, it be not spherical situation Under, refer to be replaced into the diameter of the ball in the case of volume identical ball.

On the other hand, the diameter of the drop 200 that is discharged by the 2nd drive signal PB is preferably big than the diameter of nozzle 341. The drop 200 bigger than the diameter of nozzle 341 by being set to diameter, can form point as big as possible on medium 7.

Additionally, the diameter of the drop 200 that is discharged by the 2nd drive signal PB is the 1st drop 201 and the 2nd drop 202 1 Body and form the diameter in the state of 1 big drop.

Certainly, the diameter of the drop 100 that is more preferably discharged by the 1st drive signal PA less than the diameter of nozzle 341 and And, the diameter of drop 200 discharged by the 2nd drive signal PB bigger than the diameter of nozzle 341.

In addition, the drop amount of the drop 100 that is discharged by the 1st drive signal PA is being set to MA, will drive by the 2nd When signal PB and the drop amount of drop 200 discharged are set to MB, preferably MA × 1.5≤MB.Thereby, it is possible to effectively suppress Appendicular simultaneously, formed by the pixel for constituting a little louder as much as possible on medium 7.

But, in general, in the 3 of the shear mode-type for being shared next door 32 by adjacent passage 31, in 1 passage 31 carry out for discharge driving when, the passage 31,31 of its two neighbour cannot be discharged.It is thus known that making with alternate side Formula is configured with the passing away for discharging drop and does not discharge the independent head for driving type of the dummy channels of drop.It is this 3 In the case of the independent head for driving type of sample, passing away there is a possibility that to be discharged in all pixels cycle T, institute Continuous with pixel period T that forms sometimes pixel.

Now, with regard to the drive of the drive cycle TA and the 2nd drive signal PB of the 1st drive signal PA in 1 pixel period T Dynamic cycle T B, in order to suppress appendicular while showing gray scale described later on medium 7, additionally it is possible to be set to TA=TB, but excellent Choosing is set to TA >=TB.Based on big 200 relative low speeds of drop of the 2nd drive signal PB, so by being set to TA >=TB, for example In the case of wishing to form point as big as possible as during dense gray scale etc., can be in 1 pixel period T, at short notice Substantial amounts of big drop 200 based on 2nd drive signal PB is made at high speed.

In addition, as shown in figure 3, the with regard to applying to the drive electrode with 341 corresponding passage 31 of same nozzle the 1st drives Signal PA and the 2nd drive signal PB respective expansion pulse (expansion pulse Pa1, the 1st expansion pulse Pb1, the 2nd expansion pulse Pb3), preferably crest is constant, also, the 1st driving with regard to applying to the drive electrode with 341 corresponding passage 31 of same nozzle Signal PA and the 2nd drive signal PB is respective to shrink pulse (contraction pulse Pa2, the 1st contraction pulse Pb2, the 2nd contraction pulse Pb4), crest is it is also preferred that constant.The magnitude of voltage that the expansion pulse of each drive signal PA, PB can be made and the voltage for shrinking pulse Value difference is constant, it is possible to simplifying the structure of drive control part 8 further.

When number N of the 2nd drive signal PB for applying in 1 pixel period T is N >=2, drives by each 2nd and believe Number PB and the drop 200 discharged can both be same speed, or different speed.

In fig. 8, as an example, show to drive by multiple 2 in the case of the N=3 shown in Fig. 3 and believe Drop 100,200 when number PB and each drop 200 for discharging from same nozzle 341 are set to same speed with flying of passing through of time Xiang state and the top view of the point D for thus being formed on medium 7.

In the case that each drop 200 is set to same speed, shown in such as Fig. 8 (a), in 1 pixel period T continuously 3 drops 200 that discharges are circled in the air to constant speed respectively.Then, when the final drop 100 based on the 1st drive signal PA is discharged, Drop 100 than the drop 200 discharged before it more at a high speed, so catching up with and merging.In addition, the drop that is discharged is subject to Air drag in circling in the air and slow down, so merge the drop 200 before drop is further caught up with immediately preceding it and merge, so as to In circling in the air, all drops 100,200 are merged.As a result, on medium 7, formed shown in Fig. 8 (b) by being based on 1 liquid The pixel that the point D of drop is constituted.The land after consolidation of all drops 100,200, it is possible to formed do not have landing positions to offset High-precision point D.

In addition, the pulse of the 1st expansion pulse Pb1 can be passed through based on the liquid drop speed of the drop 200 of the 2nd drive signal PB Width PWB1 is adjusting.Therefore, in the situation that the liquid drop speed of the drop 200 for making to discharge by each 2nd drive signal PB is different Under, can be carried out by adjusting pulse width PWB1 of the 1st expansion pulse Pb1.In the present embodiment, as the pulse The preferred scope of width PWB1, exemplified with more than 0.4AL and below 2.0AL scope, so within the range adjust pulse The length of width PWB1.

Now, preferably in 1 pixel period T, long from being short to according to pulse width PWB1 of the 1st expansion pulse Pb1 Sequentially, apply the 2nd drive signal PB.Thus, each drop 200 with regard to being discharged, the drop 200 that discharges afterwards, speed is got over Hurry up, so in the case that hope makes each drop 200 reliably merge in circling in the air effectively.

In fig .9, as an example, show for by multiple 2 drivings in the case of the N=3 shown in Fig. 3 Signal PB and from each drop 200 that same nozzle 341 is discharged cause the drop 200 discharged afterwards then speed be faster when drop 100th, the top view of 200 circle in the air state and the point D for thus being formed on medium 7 that pass through with the time.

In this case, as shown in Fig. 9 (a), 3 drops 200 that continuously discharges in 1 pixel period T are circling in the air Middle merging and formed merge drop, be finally based on the 1st drive signal PA final drop 100 catch up with merging drop and merge, so as to In circling in the air, all drops 100,200 merge.As a result, on medium 7, forming the point based on 1 drop shown in Fig. 9 (b) D.In this case, all drops 100,200 and after consolidation land, it is possible to formed do not have landing positions skew High-precision point D.

On the other hand, additionally it is possible in 1 pixel period T, according to the arteries and veins of the 1st expansion pulse Pb1 of the 2nd drive signal PB Width PWB1 order, i.e. liquid drop speed from long to short is rushed near slow order, apply the 2nd drive signal PB.

In Fig. 10, as an example, show for by multiple 2 drives in the case of the N=3 shown in Fig. 3 Dynamic signal PB and from each drop 200 that same nozzle 341 is discharged cause the drop 200 first discharged then speed be faster when liquid The top view of circle in the air state and the point D for thus being formed on medium 7 that pass through with the time of drop 100,200.

In this case, as shown in Figure 10 (a), discharged with before it based on the drop 100 of the 1st drive signal PA Drop 200 merge and form merging drop, in addition, shown in such as Figure 10 (b), formed overlapped on medium 7 by multiple points and The pixel that the 1 point D for becoming is constituted.Its reason is, the energy of the drop 100 that early stage after discharge is finally discharged is damaged Lose.

With regard to the point D shown in the Figure 10 (b), as described later, in the drop that is discharged in 1 pixel period T by change There is the worry that landing positions slightly offset whenever drop amount difference carrying out in the purposes of expressing gradation in amount (number of drops), But big impact will not be caused to image quality.In addition, obtaining coating merely with a little louder the situation as recorded solid image Have no effect in the purposes of amount.

Next, explanation carries out the situation of expressing gradation in the present invention.

In the present invention, by, in 1 pixel period T, applying N number of 2nd drive signal PB, at least finally apply the 1st Drive signal PA, so as to discharge drop from same nozzle 341, forms the pixel being made up of drop on medium 7, also, according to View data, makes number N of the 2nd drive signal PB of applying change by more than 0 integer, so as to make size not on medium 7 Same point, forms the pixel of the point based on all size, thus, it is possible to carry out expressing gradation on medium 7.

Even if carrying out gray scale chart thereby, it is possible to provide by making the number of drops that discharges in 1 pixel period T change Now, it is also possible to which while suppressing productivity ratio to reduce, suppression produces appurtenance, and also landing positions can be suppressed to offset, energy Driving method and the ink-jet recording apparatus 1 of the ink gun 3 of the image record of high-quality are enough carried out.In addition, only changing in 1 picture Number N of the 2nd drive signal PB for applying in plain cycle T, it is possible to simply representing gradation.

Figure 11 is shown using the 1st drive signal PA and the 2nd drive signal PB described above carries out expressing gradation In the case of the present invention in driving method an example.Here, showing by making to apply in 1 pixel period T The number of the 2nd drive signal PB is changed to maximum 4 (N=4) from 0 (N=0) to carry out from 0 (minimum ash of grade (Level) Degree) to class 5 (maximum gray scale) this 6 stages expressing gradation example.Additionally, grade 0 is not apply any drive signal Situation.

Performance can be stored in advance in which be mapped from grade 1 to class 5 in drive control part 8 with each gray scale Each drive signal group of gray scale.Drive control part 8 passes through to select desired gray scale according to view data, and recalls corresponding Drive signal group is applying to the end 3.

In the case of expressing gradation is carried out, in addition to not applying the grade 0 of drive signal completely, from grade 1 to In class 5, also include not applying the stage (N=0) of the 2nd drive signal PB, however, in which ash from grade 1 to class 5 In degree, all in the last of 1 pixel period T, the 1st drive signal PA must be applied.Therefore, from grade 1 to any of class 5 One gray scale, all can suppress appurtenance as mentioned above.Additionally, in any one gray scale from grade 1 to class 5, finally applying Plus the 1st drive signal PA all applied in the way of becoming the same timing in 1 pixel period T.

In addition, here is also contemplated by the 1st drive signal PA and discharges the drop 100 of 6pl, by the 2nd drive signal PB and discharge the drop 200 of 10pl.Therefore, grade 1=6pl, grade 2=16pl, grade 3=26pl, class 4=36pl, etc. Level 5=46pl, can show wide gray scale in the state of the minimum liquid measure (6pl) based on the 1st drive signal PA is guaranteed.

But, in the number of drops change for so making to discharge in 1 pixel period T come in the case of carrying out expressing gradation, The landing positions skew of each gray scale throws into question.Its reason is, according to the timing that each drop that is discharged is merged, drop Velocity variations.Particularly, discharge when the drop 100 that is discharged by the 1st drive signal PA and by the 2nd drive signal PB The energy of drop 100 when drop 200 merges in circling in the air, is lost, liquid drop speed is impacted.Its reason is, compared to liquid Drop 100, drop 200 is relatively bigger drop.Therefore, in the only situation of 1 drop 100 of discharge and in addition to drop 100 In the case of also discharging multiple drops 200, it is possible to which landing positions are slightly different.

By the liquid drop speed of the drop 100 based on the 1st drive signal PA be set to VA, its drop amount is set to MA, by base When the liquid drop speed of the drop 200 of the 2nd drive signal PB is set to VB, its drop amount is set to MB, impact during merging is relied on In ratio (MA × VA)/(MB × VB) of big drop and the quantity of motion of droplet, the impact land is depended on until between medium 7 Gap the distance between (3 nozzle face with the surface of medium 7) L.In addition, if number N of the 2nd drive signal PB becomes many and becomes Become N >=3, then the final tendency for merging number of times increase is produced, so the problem of landing positions skew is more notable compared with other.

Therefore, in the case that number N of the 2nd drive signal PB for applying in 1 pixel period T is N >=3, preferably Until at least have left the position of (MA × VA)/(MB × VB) × L from nozzle, do not make based on finally applying in 1 pixel period T Plus the drop 100 of the 1st drive signal PA and formed based on the drop 200 of the 2nd drive signal PB for applying before it Merge drop.That is, drop 100 and drop 200 are more than conjunction after have left the position of (MA × VA)/(MB × VB) × L from nozzle And or in an overlapping manner land on medium 7.

Landing positions thereby, it is possible to suppress each gray scale offset.Alternatively, it is also possible to avoid unnecessarily increasing at 1 The speed of the drop 100 of the last discharge in pixel period T, so can also suppress further to produce appurtenance.

In the above description, as 3, shearing becomes exemplified with the next door 32 for making between adjacent passage 31,31 The head of shape is set to the pressure generating unit being made up of piezoelectric elements such as PZT simultaneously but it is also possible to be by the upper wall of passage or lower wall Make the upper wall or lower wall that the head of detrusion to occur.

In addition, the ink gun in the present invention is not limited to shear mode-type completely.For example, it is also possible to be formed by oscillating plate One wall of pressure chamber simultaneously makes the vibration panel vibration come to pressure chamber by the pressure generating unit being made up of piezoelectric elements such as PZT Interior ink gives the ink gun of the type for the pressure that discharges.

Embodiment

Hereinafter, embodiments of the invention are described, but the invention is not restricted to the embodiment.

(embodiment 1)

Prepare the ink gun (diameter=24 μm of nozzle, AL=3.7 μ s) of the shear mode-type shown in Fig. 2.As ink, At 40 DEG C using UV atherosclerotic type ink.The viscosity of ink now is 0.01Pa s.As medium, using ink-jet paper, Gap L between dielectric surface and nozzle face is set to 1.5mm.

As the 1st drive waveforms, using the 1st drive waveforms PA of the square wave shown in Fig. 4 (a), ripple is driven as the 2nd Shape, using the 2nd drive waveforms PB of the square wave shown in Fig. 4 (b).Each pulse width and drive cycle are as described below.

<1st drive waveforms PA>

Pulse width PWA1=3.7 μ s (1AL) of expansion pulse Pa1

Shrink pulse width PWA2=7.4 μ s (2AL) of pulse Pa2

Drive cycle TA=26 μ s (7AL)

Additionally, between expansion pulse Pa1 and contraction pulse Pa2, being provided with stopping period for 0.5 μ s (below 1/4AL) PWA3.

<2nd drive waveforms PB>

Pulse width PWB1=2.4 μ s (0.65AL) of the 1st expansion pulse Pb1

1st pulse width PWB2=1.8 μ s (0.5AL) for shrinking pulse Pb2

Pulse width PWB3=3.7 μ s (1AL) of the 2nd expansion pulse Pb3

2nd pulse width PWB4=7.4 μ s (2AL) for shrinking pulse Pb4

Drive cycle TB=18.5 μ s (5AL)

The reference potential of the 1st drive signal PA and the 2nd drive signal PB is set to 0 current potential, expansion pulse (Pa1, Pb1, Pb3 magnitude of voltage (| Von |)) is 11V, and the magnitude of voltage (| Voff |) for shrinking pulse (Pa2, Pb2, Pb4) is constant for 5.5V.

In the same manner as Fig. 3, number N of the 2nd drive signal PB in 1 pixel period T is set to N=3, finally applies 1 Individual 1st drive signal PA, continuously discharges 3 big drops and 1 droplet.

The liquid drop speed of the drop that is discharged by the 1st drive signal PA is 6m/s, is discharged by the 2nd drive signal PB 3 drops each liquid drop speed be 5m/s, all identical.In addition, 1 drop that is discharged by the 1st drive signal PA Drop amount is 6pl (22.5 μm of diameter), and the drop amount of 3 drops that is discharged by the 2nd drive signal PB is that 10pl is (straight respectively 26.5 μm of footpath).

If appurtenance is produced in the drop that is discharged, form the spittle for being caused by appurtenance drop around point. Therefore, microscope observation is carried out to the point on medium, with regard to appendicular generation situation, is commented according to following benchmark Valency.Table 1 illustrates its result.

◎：Appurtenance is not produced completely.

○：Although it is slightly to produce appurtenance but do not have influential grade completely to image quality.

△：It is the grade for image quality somewhat being impacted due to appurtenance.

×：It is the grade for producing substantial amounts of appurtenance and image quality being impacted.

In addition, microscope observation is carried out to the point for being formed on medium therefrom, with regard to the generation shape of landing positions skew Condition, is evaluated according to following benchmark.Table 1 illustrates its result.

◎：Offset without landing positions completely and form high-precision pixel.

○：Though be somewhat have assured result position skew do not have influential grade completely to image quality.

△：It is to have assured result position skew and the grade that somewhat image quality impacted.

×：It is the grade for occurring big landing positions to offset and image quality being impacted.

(comparative example 1)

As shown in Figure 12 (a), in 1 pixel period T, the 1st drive signal PA is not applied, only by the 2nd drive signal PB even Apply 4 continuously, in addition, same as Example 1, similarly have rated appendicular generation situation and landing positions are inclined Move.Table 1 illustrates its result.

(comparative example 2)

As shown in Figure 12 (b), 1 before putting on the timing for applying the 1st drive signal PA in 1 pixel period T, finally Apply the 2nd drive signal PB, in addition, same as Example 1, appendicular generation situation is similarly have rated with dropping place Put the situation occurred of skew.Table 1 illustrates its result.

(comparative example 3)

Expansion pulse Pa1 in 1st drive signal PA is set to 1.2 μ with the period PWA3 that stops between pulse Pa2 is shunk S (more than 1/4AL), in addition, same as Example 1, similarly have rated appendicular generation situation and landing positions are inclined The situation occurred of shifting.

Now, the drop that finally discharges is less than the drop that is discharged by the 2nd drive signal PB similarly to Example 1 Drop (6pl), but be set to longer by the period PWA3 that will stop, liquid drop speed becomes 4.5m/s, than driving letter by the 2nd Number PB and the drop discharged is slow.Table 1 illustrates its result.

(embodiment 2)

Pulse PWA1=5.6 μ s (1.5AL) of expansion pulse Pa1 by being set in the 1st drive signal PA, contraction pulse Pulse width PWA=11.2 μ s (3AL) of Pa2, so as to be set to 8pl by the drop amount of 1 drop based on the 1st drive signal PA (25 μm of diameter), and the diameter drop bigger than nozzle footpath (24 μm) is set to, in addition, same as Example 1, similarly evaluate Appendicular generation situation and the situation occurred of landing positions skew.Table 1 illustrates its result.

(embodiment 3)

By by each pulse width PWB1 of the 1st expansion pulse Pb1 in 3 the 2nd drive waveforms PB according in 1 pixel The order for applying in cycle T is set to 2.2 μ s, 2.4 μ s, 2.6 μ s, and the drop that sends out afterwards then makes liquid drop speed faster, except this with Outward, same as Example 1, similarly have rated the situation occurred of appendicular generation situation and landing positions skew.Table 1 shows Go out its result.

Additionally, each liquid drop speed of the drop that is discharged by 3 the 2nd drive signal PB be successively 4.5m/s, 5.0m/s, 5.5m/s.In addition, each drop amount of the drop that is discharged by 3 the 2nd drive signal PB be successively 9.5pl (26 μm of diameter), 10pl (26.5 μm of diameter), 10.5pl (26 μm of diameter).

(embodiment 4)

By by each pulse width PWB1 of the 1st expansion pulse Pb1 in 3 the 2nd drive waveforms PB according in 1 pixel The order for applying in cycle T is set to 2.6 μ s, 2.4 μ s, 2.2 μ s, and the drop that sends out afterwards then makes liquid drop speed slower, except this with Outward, same as Example 1, similarly have rated the situation occurred of appendicular generation situation and landing positions skew.Table 1 shows Go out its result.

Additionally, each liquid drop speed of the drop that is discharged by 3 the 2nd drive signal PB be successively 5.5m/s, 5.0m/s, 4.5m/s.In addition, each drop amount of the drop that is discharged by 3 the 2nd drive signal PB be successively 10.5pl (27 μm of diameter), 10pl (26.5 μm of diameter), 9.5pl (26 μm of diameter).

(embodiment 5)

Number N using the 2nd drive signal PB in embodiment 3 is set to the situation of N=3 as maximum gray scale, Jin Erli Reduced with number N for making in 1 pixel period T one by one and be set to 4 grades of N=2, N=1, N=0 to implement gray scale driving, The appendicular confirmation for carrying out the point of the landing positions skew between gray scale and each gray scale is tested.Table 1 illustrates its result.

In the present embodiment, based on drop amount MA=6pl of the drop of the 1st drive signal PA, its liquid drop speed VA=6m/ S, based on drop amount MB=10.5pl of drop of the 2nd drive signal PB, its liquid drop speed VB=5.5m/s, dielectric surface and spray Gap L=1.5mm between mouth face, so (L × MA × VA)/(MB × VB) is 0.94mm.

The result that is observed by drop observation device, it is thus identified that based on the last applying in 1 pixel period T The drop of 1 drive signal PA and have left from nozzle based on the drop of the 2nd drive signal PB for applying before it The position of 0.94mm does not form merging drop.

Table 1 illustrates the result of appurtenance and landing positions skew.In the present embodiment, the land between gray scale are not observed Position offsets, and obtains good image.

[table 1]

Claims

1. a kind of driving method of ink gun, be by apply drive signal to pressure generating unit and to the liquid in pressure room Give the driving method of the ink gun for making that for the pressure that discharges drop is discharged from nozzle, it is characterised in that

The drive signal includes at least following 2 kinds of drive signals：Discharge the 1st drive signal of drop and drive with the described 1st Signal discharges the 2nd drive signal of big drop with comparing relative low speeds,

By applying N number of 2nd drive signal in 1 pixel period, at least finally applying the 1st drive signal, So that drop is discharged from the same nozzle, the pixel based on the point being made up of the drop, also, institute is formed on medium State the integer that N is more than 1.

2. a kind of driving method of ink gun, be by apply drive signal to pressure generating unit and to the liquid in pressure room Give the driving method of the ink gun for making that for the pressure that discharges drop is discharged from nozzle, it is characterised in that

By applying N number of 2nd drive signal in 1 pixel period, at least finally applying the 1st drive signal, So that drop is discharged from the same nozzle, the pixel based on the point being made up of the drop, also, root is formed on medium According to view data, make the N change by more than 0 integer and point of different sizes is made on medium, carry out expressing gradation.

3. the driving method of ink gun according to claim 2, it is characterised in that

The distance between the nozzle face of the ink gun and the medium is set to L, by the liquid based on the 1st drive signal Drop speed is set to VA, drop amount is set to MA, will be set to VB, set drop amount based on the liquid drop speed of the 2nd drive signal During for MB,

In the case of N >=3, until the position of (L × MA × VA)/(MB × VB) is at least have left from the nozzle, based on institute State the drop of the 1st drive signal and not formed based on the drop of the 2nd drive signal before it merges drop.

4. the driving method of the ink gun according to claim 1,2 or 3, it is characterised in that

The diameter of the drop that is discharged by the 1st drive signal is less than the diameter of the nozzle.

5. the driving method of the ink gun according to any one in Claims 1 to 4, it is characterised in that

The diameter of the drop that is discharged by the 2nd drive signal is bigger than the diameter of the nozzle.

6. the driving method of the ink gun according to any one in Claims 1 to 5, it is characterised in that

When the drive cycle of the 1st drive signal is set to TA, the drive cycle of the 2nd drive signal is set to TB, TA≥TB.

7. the driving method of the ink gun according to any one in claim 1～6, it is characterised in that

By the drop amount of the drop that is discharged by the 1st drive signal be set to MA, will be by the 2nd drive signal When the drop amount of the drop of discharge is set to MB, MA × 1.5≤MB.

8. the driving method of the ink gun according to any one in claim 1～7, it is characterised in that

The pressure generating unit makes the volume of the pressure chamber expand or shrink by driving,

1st drive signal and the 2nd drive signal include to make the cubical expansion of the pressure chamber and certain respectively The expansion pulse of the after-contraction of time and the contraction pulse for making the volume contraction of the pressure chamber and expanding after some time, The 1st drive signal applied by the pressure generating unit corresponding with the same nozzle and the described 2nd drives letter The crest of number respective expansion pulse is constant, also, the pressure generating unit corresponding with the same nozzle is applied Plus the 1st drive signal and the 2nd drive signal respective described shrink pulse crest constant.

9. the driving method of ink gun according to claim 8, it is characterised in that

1st drive signal has the expansion pulse, the contraction pulse and connects the expansion pulse and the receipts Stopping period between vena contracta punching.

10. the driving method of ink gun according to claim 9, it is characterised in that

The pulse width of the expansion pulse in the 1st drive signal is more than 0.8AL and below 1.2AL, and wherein, AL is The 1/2 of the acoustic resonance cycle of the pressure wave in the pressure chamber,

The pulse width for shrinking pulse is more than 1.8AL and below 2.2AL,

The period of stopping is below 1/4AL.

The driving method of 11. ink guns according to claim 8,9 or 10, it is characterised in that

2nd drive signal is according to time serieses order with the 1st expansion pulse being made up of the expansion pulse, by described Shrink the 1st of pulse composition and shrink pulse, the 2nd expansion pulse being made up of the expansion pulse and by the contraction pulse structure The 2nd contraction pulse for becoming.

The driving method of 12. ink guns according to claim 11, it is characterised in that

The pulse width of the 1st expansion pulse in the 2nd drive signal is more than 0.4AL and below 2.0AL, wherein, AL is the 1/2 of the acoustic resonance cycle of the pressure wave in the pressure chamber,

The pulse width of the 1st contraction pulse is more than 0.4AL and below 0.7AL,

The pulse width of the 2nd expansion pulse is more than 0.8AL and below 1.2AL,

Described 2nd pulse width for shrinking pulse is more than 1.8AL and below 2.2AL.

The driving method of 13. ink guns according to claim 12, it is characterised in that

At N >=2, the pulse width of the 1st expansion pulse of N number of described 2nd drive signal for applying in 1 pixel period Degree is respectively different.

The driving method of 14. ink guns according to claim 13, it is characterised in that

In 1 pixel period, applied from long order is short to according to the pulse width of the 1st expansion pulse.

The driving method of 15. ink guns according to any one in claim 1～14, it is characterised in that

1st drive signal and the 2nd drive signal are all square waves.

The driving method of 16. ink guns according to any one in claim 1～15, it is characterised in that

1st drive signal be in the multiple drive signals for being arranged in 1 pixel period in temporal sequence for being formed The drive signal of minimum drop.

A kind of 17. ink-jet recording apparatus, possess：

Ink gun, by the driving of pressure generating unit the liquid in pressure room is given for discharge pressure, make drop from Nozzle is discharged；And

The ink-jet recording apparatus are characterised by,

The drive control unit is at least applied finally by applying N number of 2nd drive signal in 1 pixel period 1st drive signal, so that drop is discharged from the same nozzle, forms based on being made up of the drop on medium The pixel of point, also, the N is more than 1 integer.

A kind of 18. ink-jet recording apparatus, possess：

The ink-jet recording apparatus are characterised by,

The drive control unit is at least applied finally by applying N number of 2nd drive signal in 1 pixel period 1st drive signal, so that drop is discharged from the same nozzle, forms based on being made up of the drop on medium The pixel of point, also, according to view data, so that the N is changed by more than 0 integer and make on medium of different sizes Point, carries out expressing gradation.

19. ink-jet recording apparatus according to claim 18, it is characterised in that

20. ink-jet recording apparatus according to claim 17,18 or 19, it is characterised in that

21. ink-jet recording apparatus according to any one in claim 17～20, it is characterised in that

22. ink-jet recording apparatus according to any one in claim 17～21, it is characterised in that

23. ink-jet recording apparatus according to any one in claim 17～22, it is characterised in that

24. ink-jet recording apparatus according to any one in claim 17～23, it is characterised in that

25. ink-jet recording apparatus according to claim 24, it is characterised in that

26. ink-jet recording apparatus according to claim 25, it is characterised in that

The pulse width for shrinking pulse is more than 1.8AL and below 2.2AL,

The period of stopping is below 1/4AL.

27. ink-jet recording apparatus according to claim 24,25 or 26, it is characterised in that

2nd drive signal have be made up of the expansion pulse the 1st expansion pulse, by described shrink that pulse is constituted the 1 contraction pulse, the 2nd expansion pulse being made up of the expansion pulse and the 2nd contraction pulse being made up of the contraction pulse.

28. ink-jet recording apparatus according to claim 27, it is characterised in that

The pulse width of the 2nd expansion pulse is more than 0.8AL and below 1.2AL,

29. ink-jet recording apparatus according to claim 28, it is characterised in that

30. ink-jet recording apparatus according to claim 29, it is characterised in that

31. ink-jet recording apparatus according to any one in claim 17～30, it is characterised in that

1st drive signal and the 2nd drive signal are all square waves.

32. ink-jet recording apparatus according to any one in claim 17～31, it is characterised in that