JP2008238485A - Inkjet recording method and inkjet recording apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To improve stability of fine liquid droplet delivering of an aqueous ink with a high ratio of a high boiling point aqueous solvent. <P>SOLUTION: An inkjet recording method is characterized in that by using an ink for inkjet comprising a pigment, water and a specified organic solvent of ≥50 mass% and <80 mass% to the total mass of the ink, liquid droplets with ≤3 pl are delivered from a funnel-like nozzle composed of a cylindrical part with an extending angle of 0-10° from an opening on the ink delivering side toward the ink inlet side and a conical part arranged on the ink inlet side of the cylindrical part and with an extending angle of 30-70° toward the ink inlet side. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an ink jet recording method and an ink jet recording apparatus, and more particularly to an ink jet recording method and an ink jet recording apparatus using an aqueous ink having a high ratio of a high boiling point aqueous solvent.

  The ink jet recording method is a method for recording on a recording medium by flying droplets (ink droplets) ejected from a nozzle, and has excellent noise characteristics, low running cost, and high definition for a wide variety of recording media. Since images can be recorded at a relatively high speed, they are used in a wide range of fields.

  In a recording apparatus adopting an ink jet system, that is, an ink jet recording apparatus (ink jet printer), a short recording head (serial head) is perpendicular to the recording medium conveyance direction (sub-scanning direction) (the width direction of the recording medium; There are a serial type in which recording is performed while reciprocating in the main scanning direction) and a single pass type in which recording is performed using a long recording head (line head) corresponding to the width of the recording medium. Among these, the single-pass type recording apparatus is suitable for high-speed recording because it is not necessary to move the recording head in the width direction of the recording medium, and is particularly desired for office use.

  Further, office recording apparatuses are strongly required to enable high-quality printing on plain paper, not expensive dedicated paper. Further, since it is continuously operated at a high speed for a long time as compared with a home printer, the required quality for reliability is high.

  When recording on plain paper by an ink jet recording apparatus, there are problems such as image bleeding, feathering, and back-through (a phenomenon in which the printed ink passes through the recording medium and the printed image appears on the back surface). In addition, when water-based ink is used, in addition to the above problems, paper curling and cockling due to permeated water and ejection reliability of the recording head (nozzle clogging due to water evaporation) become problems.

  In order to solve such a problem, an ink jet recording method using an ink mainly containing a water-soluble solvent while suppressing the water content has been proposed (for example, see Patent Documents 1 and 2). However, when an attempt was made to eject fine droplets of 2 pl or less using this ink in order to record a high-resolution image, it would be unexpected that a nozzle that would not eject would be likely to occur if it was ejected for a long time. It turns out that a problem arises.

  In addition, with respect to the nozzles of the ink jet recording head (ink jet head), the funnel-shaped nozzle 10 (described later) of the present invention is used rather than the trumpet-shaped nozzle 90 (see FIG. 12) that tapers toward the ink ejection side. It is known that the meniscus position can be stabilized more and the discharge stability can be improved (see, for example, Patent Document 3).

  In general, water is low-cost, chemically non-reactive, non-toxic, has no adverse effects on the environment, and has no odor. Therefore, as an ink (ink-jet ink) for home and office recording devices, Water-based inks are preferably used. Further, when a pigment is used as a coloring material, it is known that the dispersion stability of the pigment is higher in water than in an organic solvent, and particularly advantageous when the pigment concentration is 10% by mass or more.

  There are two main problems with water-based inks as follows.

  First, as the first problem, there is a non-ejection that occurs as a result of water being evaporated by the ink meniscus inside the nozzle and the resulting ink being concentrated to increase the viscosity. This can be recovered by maintenance of the recording head before printing or during printing (suctioning ink from nozzles, wiping nozzle surfaces). Further, it can be prevented by regular idle ejection (preliminary ejection) and maintenance during printing. However, in the case of the single-pass type, which requires high-speed recording, because there is a need to reduce maintenance during printing, and division printing is not possible unlike the serial type, nozzle failure (nozzle due to non-ejection or deviation in droplet flight direction) Defects are easily noticeable, and water evaporation at the nozzles is particularly a problem with single-pass recording devices.

  As a second problem, when water penetrates into paper, water molecules enter between the cellulose molecules of the paper, and the hydrogen bonds between the cellulose fibers are cut off. When the water molecules are removed by drying again and the hydrogen bonds between the cellulose molecules are restored, the rearrangement of the cellulose molecules occurs. For this reason, once water penetrates into the paper, it once curls due to swelling, and when dried, the wet side contracts and curls in the opposite direction. In addition, when there are wet and non-wet portions, wavy cockling occurs. In addition to the problem that the quality of the final printed matter is deteriorated, these cause an accumulation error in the accumulation unit of the printer and an obstacle to paper conveyance.

In order to avoid such problems of water-based inks, oil-based solvent inks that use only volatile organic solvents that do not use water as a solvent have been studied. However, oil-based solvent inks penetrate quickly into paper and dry quickly, and do not cause paper curl. However, because of the rapid penetration, there is a problem that bleeding occurs, character quality is impaired, and showthrough tends to occur. .
JP 2005-220296 A Japanese Patent Laid-Open No. 2005-220297 Japanese Patent Laid-Open No. 5-229127

  The present invention has been made in view of such circumstances, and an object of the present invention is to provide an ink jet recording method and an ink jet recording apparatus in which the stability of fine droplet discharge of an aqueous ink having a high ratio of a high boiling point aqueous solvent is improved. And

  In order to achieve the object, the invention according to claim 1 contains a pigment and water, and has the following general formula (I):

（ただし、ｎは２又は３、Ｒ_１は炭素数１〜４のアルキル基、Ｒ_２は水素又はメチル基、Ｒ_３は水素又はアセチル基を示す。）で表される有機溶媒をインク全質量に対し５０質量％以上８０質量％未満含有するインクジェット用インクを用いて、インク吐出側の開口からインク流入側に向かって０度以上１０度以下の広がり角度をもつ円柱部と、前記円柱部のインク流入側に配置され、インク流入側に向かって３０度以上７０度以下の広がり角度をもつ円錐部とから構成される漏斗状ノズルから３ｐｌ以下の液滴を吐出することを特徴とするインクジェット記録方法を提供する。

(Where n is 2 or 3, R ₁ is an alkyl group having 1 to 4 carbon atoms, R ₂ is hydrogen or a methyl group, and R ₃ is hydrogen or an acetyl group.) A cylindrical portion having a spread angle of 0 degrees or more and 10 degrees or less from the opening on the ink discharge side toward the ink inflow side using an inkjet ink containing 50 mass% or more and less than 80 mass% with respect to the cylinder section; Inkjet recording characterized in that a droplet of 3 pl or less is ejected from a funnel-shaped nozzle that is arranged on the ink inflow side and is composed of a conical portion having a spread angle of 30 degrees to 70 degrees toward the ink inflow side Provide a method.

  According to the present invention, by using a water-based ink having a high ratio of a high-boiling aqueous solvent, fine droplets are ejected from a funnel-shaped nozzle including a cylindrical portion and a conical portion having a spread angle (taper angle) within a predetermined range. In addition, ejection stability is improved without causing ejection failure such as non-ejection. For this reason, curl and cockle of the recording medium can be suppressed, and high-resolution image recording on the recording medium can be performed.

  A second aspect of the present invention is the ink jet recording method according to the first aspect, wherein a droplet of 2 pl or less is ejected from the funnel-shaped nozzle.

  In the present invention, it is preferable that the amount of discharged droplets of the funnel-shaped nozzle is 2 pl or less. The effect of the present invention becomes more prominent than when no funnel nozzle is used.

  A third aspect of the present invention is the ink jet recording method according to the first or second aspect, wherein an opening diameter of the funnel-shaped nozzle on the ink discharge side is 30 μm or less.

  The opening diameter on the ink discharge side of the funnel-shaped nozzle is preferably 30 μm or less, and particularly preferably 20 μm or less. This is a preferred embodiment for discharging fine droplets from a funnel-shaped nozzle.

  A fourth aspect of the present invention is the ink jet recording method according to any one of the first to third aspects, wherein recording is performed on plain paper.

  The present invention is particularly suitable for recording on plain paper, can effectively suppress curl and cockle during recording, and can improve high-resolution image recording by improving ejection stability.

  A fifth aspect of the present invention is the ink jet recording method according to any one of the first to fourth aspects, wherein the funnel-shaped nozzles are arranged over a length corresponding to the width of the recording medium. Recording is performed using a head.

  According to this aspect, since it is not necessary to move the recording head (line head) in the width direction of the recording medium (direction orthogonal to the paper transport direction), high-speed recording is possible.

  In order to achieve the above object, the invention according to claim 6 includes a cylindrical portion having a spread angle of 0 ° to 10 ° from the ink discharge side opening toward the ink inflow side, and Disposed on the ink inflow side is a discharge means having a funnel-shaped nozzle composed of a conical portion having a spreading angle of not less than 30 degrees and not more than 70 degrees toward the ink inflow side, and the discharge means contains pigment and water. And the following general formula (I)

（ただし、ｎは２又は３、Ｒ_１は炭素数１〜４のアルキル基、Ｒ_２は水素又はメチル基、Ｒ_３は水素又はアセチル基を示す。）で表される有機溶媒をインク全質量に対し５０質量％以上８０質量％未満含有するインクジェット用インクを前記漏斗状ノズルから３ｐｌ以下の液滴として吐出する手段であることを特徴とするインクジェット記録装置を提供する。

(Where n is 2 or 3, R ₁ is an alkyl group having 1 to 4 carbon atoms, R ₂ is hydrogen or a methyl group, and R ₃ is hydrogen or an acetyl group.) In contrast, the present invention provides an ink jet recording apparatus, characterized in that it is means for ejecting ink jet ink containing 50 mass% or more and less than 80 mass% as droplets of 3 pl or less from the funnel-shaped nozzle.

  According to the present invention, by using a water-based ink having a high ratio of a high-boiling aqueous solvent, fine droplets are ejected from a funnel-shaped nozzle including a cylindrical portion and a conical portion having a spread angle (taper angle) within a predetermined range. In addition, ejection stability is improved without causing ejection failure such as non-ejection. For this reason, curl and cockle of the recording medium can be suppressed, and high-resolution image recording on the recording medium can be performed.

  A seventh aspect of the present invention is the ink jet recording apparatus according to the sixth aspect, wherein the discharge means includes a nozzle forming member on which the funnel-shaped nozzle is formed, and the nozzle forming member is made of polyimide. It is characterized by.

  According to the aspect in which the nozzle forming member (nozzle plate) is made of polyimide, it becomes possible to process the funnel-shaped nozzle with high accuracy by an excimer laser, thereby eliminating variations in the amount of discharged droplets of the funnel-shaped nozzle, The image quality can be further improved.

  The invention according to claim 8 is the ink jet recording apparatus according to claim 6 or 7, wherein the discharge means is a line in which the funnel-shaped nozzles are arranged over a length corresponding to the width of the recording medium. It is a head.

  According to this aspect, since it is not necessary to move the recording head (line head) in the width direction of the recording medium (direction orthogonal to the paper transport direction), high-speed recording is possible.

  According to the present invention, by using a water-based ink having a high ratio of a high-boiling aqueous solvent, fine droplets are ejected from a funnel-shaped nozzle including a cylindrical portion and a conical portion having a spread angle (taper angle) within a predetermined range. In addition, ejection stability is improved without causing ejection failure such as non-ejection. For this reason, curl and cockle of the recording medium can be suppressed, and high-resolution image recording on the recording medium can be performed.

  Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

[Description of inkjet ink]
The ink-jet ink (hereinafter sometimes simply referred to as “ink”) applied to the present invention is an ink containing a predetermined ratio of a specific organic solvent (high boiling point aqueous solvent) as well as a pigment and water. . Hereinafter, the ink-jet ink of the present invention will be described.

<Pigment>
The pigment used in the present invention is not particularly limited, and any pigment can be appropriately selected from known pigments as long as the hue and color density suitable for the intended use of the ink can be achieved.

  As the pigment used in the present invention, either an organic pigment or an inorganic pigment can be used, and as the black pigment, a carbon black pigment or the like is preferably exemplified. In general, pigments of three primary colors of black and cyan, magenta, and yellow are used, but pigments having other hues such as red, green, blue, brown, white, gold, silver, etc. The metallic luster pigment, colorless or light-colored extender pigment, and the like can also be used depending on the purpose.

  In addition, particles having silica, alumina, resin, or the like as a core material and having a dye or pigment fixed on the surface, an insoluble raked product of a dye, a colored emulsion, a colored latex, or the like can also be used as a pigment.

  Furthermore, resin-coated pigments can also be used. This is called a microcapsule pigment, and is also available as a commercial product from Dainippon Ink and Chemicals, Toyo Ink, etc.

  The volume average particle diameter of the pigment particles contained in the liquid in the present invention is preferably in the range of 30 to 250 nm, more preferably 50 to 200 nm, from the viewpoint of balance between optical density and storage stability. . Here, the volume average particle diameter of the pigment particles can be measured by a measuring device such as LB-500 (manufactured by HORIBA).

  In the present invention, the content of the pigment in the ink is preferably in the range of 0.1% by mass to 20% by mass in terms of solid content from the viewpoint of optical density and jetting stability, and is preferably 1% by mass to 10% by mass. % Is more preferable.

  You may use not only 1 type but 2 or more types of pigments in mixture. In addition, different pigments may be used for each ink or the same.

<Organic solvent (high boiling point organic solvent)>
In the present invention, a high-boiling organic solvent (high-boiling aqueous solvent) that is completely compatible with water, has a low viscosity, and is less volatile than water is used as the organic solvent.

  In the present invention, the high-boiling organic solvent means an organic solvent having a viscosity at 25 ° C. of 100 mPa · s or lower or a viscosity at 60 ° C. of 30 mPa · s or lower and a boiling point higher than 100 ° C.

  Here, the “viscosity” in the present invention refers to a viscosity obtained using a RE80 viscometer manufactured by Toki Sangyo Co., Ltd. The RE80 type viscometer is a conical rotor / plate type viscometer corresponding to the E type. Measurement is performed at a rotation speed of 10 rpm using the first rotor. However, for those having a viscosity higher than 60 mPa · s, measurement is performed by changing the number of revolutions to 5 rpm, 2.5 rpm, 1 rpm, 0.5 rpm, or the like as necessary.

  In the present invention, “water solubility” is the saturation concentration of water in a high-boiling organic solvent at 25 ° C., and means the mass (g) of water that can be dissolved in 100 g of the high-boiling organic solvent at 25 ° C. .

  In the present invention, the high-boiling organic solvent is preferably a compound represented by the following general formula (I).

一般式（Ｉ）中、ｎは２又は３を表し、Ｒ_１は炭素数１〜４のアルキル基を表し、Ｒ_２は水素又はメチル基を表し、Ｒ_３は水素又はアセチル基を表す。

In general formula (I), n represents 2 or 3, R ₁ represents an alkyl group having 1 to 4 carbon atoms, R ₂ represents hydrogen or a methyl group, and R ₃ represents hydrogen or an acetyl group.

  Specific examples of n = 2 include diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol monobutyl ether, diethylene glycol monoethyl ether acetate, dipropylene glycol monomethyl ether, dipropylene glycol monomethyl ether, and dipropylene glycol monoethyl ether.

  Specific examples of n = 3 include tripropylene glycol monomethyl ether, tripropylene glycol monoethyl ether, diethylene glycol monobutyl ether, diethylene glycol monoethyl ether, dipropylene monomethyl ether, tripropylene glycol monomethyl ether, and diethylene glycol monoethyl ether acetate. Can be mentioned. Among these, diethylene glycol monobutyl ether, diethylene glycol monoethyl ether, dipropylene monomethyl ether, tripropylene glycol monomethyl ether, and diethylene glycol monoethyl ether acetate are preferable.

  In the present invention, the content of the high-boiling organic solvent is preferably in the range of 50% by mass or more and less than 80% with respect to the total mass of the ink from the viewpoint of suppressing curling and cockling after printing.

[Description of recording medium]
The present invention is more effective when “plain paper” is used as the recording medium. The “plain paper” in the present invention refers to paper having no coating layer on the surface. The composition of plain paper consists of pulp fiber and filler. These pulps, fillers and sizing agents are produced by papermaking and drying. In the case of coated paper, the surface of this non-coated paper is coated with a solution obtained by adding latex as a binder to a favorite powder such as clay such as kaolin or calcium carbonate.

  Plain paper has a structure in which there are many voids having a diameter of about 15 to 20 μm of pulp fibers. On the other hand, the surface of the coated paper is smooth and the gap is about 0.1 μm.

  In this way, when water-based ink is ejected onto plain paper, ink bleeding (feathering) along the fiber, curling due to swelling of the pulp, and curling to the opposite side this time along with further drying. .

[Description of nozzle shape]
Next, the nozzle shape to which the present invention is applied will be described.

FIG. 1 is a cross-sectional view showing the nozzle shape of the present invention. As shown in FIG. 1, the nozzle 10 that is the subject of the present invention includes a cylindrical portion 10a having _a predetermined spread angle (taper angle) θa from the ink discharge side opening toward the ink inflow side, and a cylindrical portion 10a. It is arranged on the ink inflow side and is formed in a funnel shape including a conical portion 10b having _a predetermined spread angle (taper angle) θ _b (where θ _b > θ _a ) toward the ink inflow side. Hereinafter, such a funnel-shaped nozzle will be referred to as a “funnel-shaped nozzle”.

In the present invention, the taper angle theta _a of the cylindrical portion 10a in the range of 10 degrees or less than 0 degrees are preferred. Variations in the discharge direction taper angle theta _a is greater than 10 degrees is because increases.

Further, the taper angle theta _b of the conical portion 10b is preferably in the range below 70 degrees 30 degrees. When the taper angle theta _b is smaller than 30 degrees, the effect can not be obtained in the present invention that excellent intermittent printing characteristics and long printing characteristics. Further, the taper angle theta _b together is larger than 70 degrees, and difficult to form a precise nozzle holes, will decreases the rigidity of the nozzle plate (nozzle forming substrate) 12 that funnel nozzle 10 is formed, rather Since discharge performance deteriorates, it is not preferable.

Incidentally, according to the preferred range of the taper angle theta _a of the cylindrical portion 10a (0 degrees 10 degrees), but in practice a cylindrical portion 10a also includes a case configured in a conical shape, larger than the cylindrical portion 10a order to distinguish between the conical portion 10b having a taper angle theta _b, in the present specification will be referred to a portion having a taper angle theta _a ink discharge side of the funnel-shaped nozzle 10 and the "cylindrical part 10a".

In FIG. 1, the length La of the cylindrical portion 10 _a and the length L _b of the conical portion 10 _b are not particularly limited, and are set to arbitrary lengths within the range of the thickness L of the nozzle plate 12. Can do. However, from the viewpoint of securing the rigidity of the nozzle plate 12, the length La of the cylindrical portion 10a is preferably 10 μm or more, and more preferably in the range of 10 μm or more and 20 μm or less.

  In FIG. 1, the ink discharge side opening diameter D of the nozzle 10 (cylindrical portion 10 a) is not particularly limited, but is normally 50 μm or less.

  In the present invention, from the viewpoint of discharging fine droplets, the ink discharge side opening diameter D of the nozzle 10 is preferably 30 μm or less, and particularly preferably 20 μm or less. When the ink discharge side opening diameter D of the nozzle 10 is 30 μm or less, it is possible to discharge 3 pl or less of fine droplets. In addition, when the ink discharge side opening diameter D of the nozzle 10 is 20 μm or less, it is possible to discharge fine droplets of 2 pl or less.

  As the material of the nozzle plate 12, various known materials can be appropriately selected and applied as long as the nozzle hole forming method, ink resistance, and required strength are maintained. For example, corrosion-resistant metals such as stainless steel and nickel, and engineering plastics such as polyimide, polyphenylene sulfide, and polyetheretherketone can be used. Among these, polyimide is particularly preferable, and a funnel-shaped nozzle hole can be formed at high speed with high accuracy by ablation with an excimer laser. The nozzle holes can be processed by the methods described in JP2003-181668A and JP2005-153260A.

  When the droplet volume (volume) ejected from the cylindrical nozzle 92 as shown in FIG. 13 is larger than 3 pl using the inkjet ink of the present invention, the influence is small, but when the ejected droplet volume is less than 3 pl. The discharge stability is lowered, and the phenomenon becomes more prominent particularly in the case of 2 pl or less. As a result, stable ejection of the fine droplets of the inkjet ink of the present invention is impossible, and high-resolution image recording on plain paper or the like becomes difficult.

  In contrast, when the ink jet ink is ejected using the funnel-shaped nozzle 10 (see FIG. 1) of the present invention, the ejection stability does not decrease even when the ejection droplet amount is 3 pl or less. Discharging becomes possible. In particular, the difference in the effect when discharging from the cylindrical nozzle becomes significant when the amount of discharged droplets is 2 pl or less.

  As described above, according to the present invention, by using a water-based ink having a high ratio of the high-boiling aqueous solvent, by discharging fine droplets from a funnel-shaped nozzle including a cylindrical portion and a conical portion having a taper angle within a predetermined range, The discharge stability is improved without causing a discharge failure (non-discharge, etc.) of the nozzle. For this reason, curl and cockle of the recording medium can be suppressed, and high-resolution image recording on the recording medium can be performed. The present invention is particularly suitable when recording is performed on plain paper.

[Description of Inkjet Recording Device]
Next, an embodiment of the ink jet recording apparatus according to the present invention will be described in detail.

<Overall configuration>
The ink jet recording apparatus of the present embodiment is a recording apparatus including a recording head (ejection means) for ejecting ink jet ink to which the present invention is applied from a funnel nozzle (see FIG. 1). Serial type recording apparatus having a long recording head (line head) in which the amount of ejected droplets is 3 pl or less, preferably 2 pl or less, and funnel-shaped nozzles are arranged over a length corresponding to the width of the recording medium It is.

  FIG. 2 is an overall configuration diagram showing an outline of the ink jet recording apparatus. As shown in FIG. 2, the inkjet recording apparatus 100 of the present embodiment has a plurality of recording heads (hereinafter sometimes simply referred to as “heads”) 112K, 112C, 112M, and 112Y provided for each ink color. A printing unit 112, an ink storage / loading unit 114 that stores ink to be supplied to each of the heads 112K, 112C, 112M, and 112Y, and a paper feeding unit that supplies recording paper (recording medium) 116 such as plain paper 118, a decurling unit 120 for removing the curl of the recording paper 116, and a nozzle surface (ink ejection surface) of the printing unit 112, and the recording paper 116 is held while maintaining the flatness of the recording paper 116. The suction belt conveyance unit 122 that conveys, the print detection unit 124 that reads the printing result by the printing unit 112, and the printed recording paper (printed material) are discharged to the outside. A paper discharge unit 126 which comprises a.

  In FIG. 2, a magazine for rolled paper (continuous paper) is shown as an example of the paper supply unit 118, but a plurality of magazines having different paper widths, paper quality, and the like may be provided side by side. Further, instead of the roll paper magazine or in combination therewith, the paper may be supplied by a cassette in which cut papers are stacked and loaded.

  In the case of an apparatus configuration using roll paper, a cutter 128 is provided as shown in FIG. 2, and the roll paper is cut into a desired size by the cutter 128. The cutter 128 includes a fixed blade 128A having a length equal to or larger than the conveyance path width of the recording paper 116, and a round blade 128B that moves along the fixed blade 128A. The fixed blade 128A is provided on the back side of the print. The round blade 128B is arranged on the printing surface side with the conveyance path interposed therebetween. Note that the cutter 128 is not necessary when cut paper is used.

  When multiple types of recording paper are used, an information recording body such as a barcode or wireless tag that records paper type information is attached to the magazine, and the information on the information recording body is read by a predetermined reader. Therefore, it is preferable to automatically determine the type of paper to be used and perform ink ejection control so as to realize appropriate ink ejection according to the type of paper.

  The recording paper 116 delivered from the paper supply unit 118 retains curl due to having been loaded in the magazine. In order to remove this curl, the decurling unit 120 applies heat to the recording paper 116 by the heating drum 130 in the direction opposite to the curl direction of the magazine. At this time, it is more preferable to control the heating temperature so that the printed surface is slightly curled outward.

  After the decurling process, the cut recording paper 116 is sent to the suction belt conveyance unit 122. The suction belt conveyance unit 122 has a structure in which an endless belt 133 is wound between rollers 131 and 132, and at least a portion facing the nozzle surface of the printing unit 112 and the sensor surface of the printing detection unit 124 is flat. It is configured to make.

  The belt 133 has a width that is wider than the width of the recording paper 116, and a plurality of suction holes (not shown) are formed on the belt surface. As shown in FIG. 2, an adsorption chamber 134 is provided at a position facing the nozzle surface of the print unit 112 and the sensor surface of the print detection unit 124 inside the belt 133 spanned between the rollers 131 and 132. The suction chamber 134 is sucked by the fan 135 to make a negative pressure, whereby the recording paper 116 on the belt 133 is sucked and held.

  The power of a motor (not shown) is transmitted to at least one of the rollers 131 and 132 around which the belt 133 is wound, so that the belt 133 is driven in the clockwise direction in FIG. 2 and held on the belt 133. The recording paper 116 is conveyed from left to right in FIG.

  Since ink adheres to the belt 133 when a borderless print or the like is printed, the belt cleaning unit 136 is provided at a predetermined position outside the belt 133 (an appropriate position other than the print region). Although details of the configuration of the belt cleaning unit 136 are not shown, for example, there are a method of niping a brush roll, a water absorption roll, etc., an air blowing method of blowing clean air, or a combination thereof. In the case where the cleaning roll is nipped, the cleaning effect is great if the belt linear velocity and the roller linear velocity are changed.

  Although a mode using a roller / nip conveyance mechanism instead of the suction belt conveyance unit 122 is also conceivable, if the roller / nip conveyance is performed in the printing area, the roller comes into contact with the printing surface of the paper immediately after printing, so that the image blurs. There is a problem that it is easy. Therefore, as in this example, suction belt conveyance that does not contact the image surface in the printing region is preferable.

  A heating fan 140 is provided on the upstream side of the printing unit 112 on the paper conveyance path formed by the suction belt conveyance unit 122. The heating fan 140 heats the recording paper 116 by blowing heated air onto the recording paper 116 before printing. Heating the recording paper 116 immediately before printing makes it easier for the ink to dry after landing.

  The printing unit 112 is a so-called full-line type head in which a line-type head having a length corresponding to the maximum paper width is arranged in a direction (main scanning direction) orthogonal to the paper transport direction (sub-scanning direction). Each of the heads 112K, 112C, 112M, 112Y constituting the printing unit 112 has a plurality of ink discharge ports (nozzles) arranged over a length exceeding at least one side of the maximum size recording paper 116 targeted by the inkjet recording apparatus 100. It is composed of a line-type head (see FIG. 3).

  A head corresponding to each color ink in the order of black (K), cyan (C), magenta (M), and yellow (Y) from the upstream side (left side in FIG. 2) along the conveyance direction (paper conveyance direction) of the recording paper 116. 112K, 112C, 112M, and 112Y are arranged. A color image can be formed on the recording paper 116 by ejecting the color ink from each of the heads 112K, 112C, 112M, and 112Y while conveying the recording paper 116.

  As described above, according to the printing unit 112 in which the full line head that covers the entire paper width is provided for each ink color, the recording paper 116 and the printing unit 112 are relatively moved in the paper transport direction (sub-scanning direction). It is possible to record an image on the entire surface of the recording paper 116 by performing this operation only once (that is, in one sub-scan). Thereby, high-speed printing is possible and productivity can be improved as compared with a shuttle type head in which the head reciprocates in a direction (main scanning direction) orthogonal to the paper transport direction.

  In this example, the configuration of KCMY standard colors (four colors) is illustrated, but the combination of ink colors and the number of colors is not limited to this embodiment, and light ink and dark ink are added as necessary. May be. For example, it is possible to add a head for ejecting light-colored ink such as light cyan and light magenta.

  As shown in FIG. 2, the ink storage / loading unit 114 includes tanks that store inks of colors corresponding to the heads 112K, 112C, 112M, and 112Y, and each tank is connected via a conduit that is not shown. The heads 112K, 112C, 112M, and 112Y communicate with each other. Further, the ink storage / loading unit 114 includes notifying means (display means, warning sound generating means, etc.) for notifying when the ink remaining amount is low, and has a mechanism for preventing erroneous loading between colors. is doing.

  The print detecting unit 124 includes an image sensor (line sensor or the like) for imaging the droplet ejection result of the printing unit 112, and means for checking nozzle clogging and other ejection defects from the droplet ejection image read by the image sensor. Function as.

  The print detection unit 124 of this example is composed of a line sensor having a light receiving element array that is wider than at least the ink ejection width (image recording width) of each head 112K, 112C, 112M, 112Y. The line sensor includes an R sensor row in which photoelectric conversion elements (pixels) provided with red (R) color filters are arranged in a line, a G sensor row provided with green (G) color filters, The color separation line CCD sensor includes a B sensor array provided with a blue (B) color filter. Instead of the line sensor, an area sensor in which the light receiving elements are two-dimensionally arranged can be used.

  The print detection unit 124 reads the test pattern printed by the heads 112K, 112C, 112M, and 112Y for each color, and detects the ejection of each head. The ejection determination includes the presence / absence of ejection, measurement of dot size, measurement of dot landing position, and the like.

  A post-drying unit 142 is provided following the print detection unit 124. The post-drying unit 142 is means for drying the printed image surface, and for example, a heating fan is used. Since it is preferable to avoid contact with the printing surface until the ink after printing is dried, a method of blowing hot air is preferred.

  When printing on porous paper with dye-based ink, the weather resistance of the image is improved by preventing contact with ozone or other things that cause dye molecules to break by blocking the paper holes by pressurization. There is an effect to.

  A heating / pressurizing unit 144 is provided following the post-drying unit 142. The heating / pressurizing unit 144 is a means for controlling the glossiness of the image surface, and pressurizes with a pressure roller 145 having a predetermined uneven surface shape while heating the image surface, and transfers the uneven shape to the image surface. To do.

  The printed matter generated in this manner is outputted from the paper output unit 126. It is preferable that the original image to be printed (printed target image) and the test print are discharged separately. The ink jet recording apparatus 100 is provided with sorting means (not shown) for switching the paper discharge path in order to select the printed matter of the main image and the printed matter of the test print and send them to the respective discharge units 126A and 126B. ing. Note that when the main image and the test print are simultaneously formed in parallel on a large sheet, the test print portion is separated by the cutter (second cutter) 148. The cutter 148 is provided immediately before the paper discharge unit 126, and cuts the main image and the test print unit when the test print is performed on the image margin. The structure of the cutter 148 is the same as that of the first cutter 128 described above, and includes a fixed blade 148A and a round blade 148B. Although not shown, the paper output unit 126A for the target prints is provided with a sorter for collecting prints according to print orders.

  In this embodiment, a full-line head is exemplified, but the scope of application of the present invention is not limited to this, and a short head having a nozzle row having a length shorter than the width of the recording medium is arranged in the width direction of the recording medium. The present invention is also applicable to a serial type (shuttle scan type) head that performs printing in the width direction of the recording medium while scanning.

<Structure of recording head>
Next, the structure of the recording head will be described. Since the structures of the heads 112K, 112C, 112M, and 112Y provided for each ink color are common, the heads are represented by the reference numeral 150 in the following.

  FIG. 4A is a plan perspective view showing a structural example of the head 150. As shown in FIG. 4A, the head 150 of this example includes a plurality of nozzles 151 (corresponding to the nozzles 10 in FIG. 1), which are ink droplet ejection ports, and pressure chambers 52 corresponding to the nozzles 151. The ink chamber units (droplet discharge elements as recording element units corresponding to one nozzle) 153 are arranged in a staggered matrix (two-dimensional), thereby enabling the longitudinal direction of the head (paper feeding direction). The density of the substantial nozzle interval (projection nozzle pitch) projected so as to be aligned along the direction (perpendicular direction) is achieved.

  Note that the form in which the nozzle row having a length corresponding to the full width of the recording paper 116 is configured in the direction (main scanning direction) substantially orthogonal to the conveyance direction (sub-scanning direction) of the recording paper 116 is not limited to this example. For example, instead of the configuration of FIG. 4A, as shown in FIG. 4B, short head units 150 ′ in which a plurality of nozzles 151 are two-dimensionally arranged are arranged in a staggered manner and joined together. A line head having a nozzle row having a length corresponding to the entire width of the recording paper 116 may be configured.

  The pressure chamber 152 provided corresponding to each nozzle 151 has a substantially square planar shape. Nozzles 151 are disposed at substantially central portions of the pressure chambers 152, and supply ink inlets (supply ports) 154 are provided at the corners thereof. The shape of the pressure chamber 152 is not limited to this example, and the planar shape may have various forms such as a quadrangle (rhombus, rectangle, etc.), a pentagon, a hexagon, other polygons, a circle, and an ellipse. Further, the arrangement of the nozzles 151 and the supply ports 154 is not limited to the arrangement shown in FIGS.

  FIG. 5 is a cross-sectional view showing a three-dimensional configuration of a droplet discharge element for one channel (an ink chamber unit 153 corresponding to one nozzle 151).

  As shown in FIG. 5, the nozzle surface 150 a of the head 150 is constituted by a nozzle plate 160. In the nozzle plate 160, a plurality of nozzles (nozzle holes) 151 are two-dimensionally formed. 5 correspond to the funnel-shaped nozzle 10 and the nozzle plate 12 of the present invention shown in FIG. 1, respectively.

  Further, as shown in FIG. 5, the pressure chambers 152 are provided corresponding to the respective nozzles 151, and the corresponding nozzles 151 are communicated with the pressure chambers 152. The pressure chamber 152 is a space that is filled with ink to be ejected from the nozzle 151.

  A supply port 154 for supplying ink is formed at one end of the pressure chamber 152, and the pressure chamber 152 communicates with the common channel 155 through the supply port 154.

  The common channel 155 is a space for storing ink to be supplied to the plurality of pressure chambers 152, and communicates with each pressure chamber 152 via the supply port 154. The ink supplied from the ink storage / loading unit 114 shown in FIG. 2 to the recording head 150 is temporarily stored in the common flow path 155 and distributed and supplied to the pressure chambers 152.

  On the vibration plate 156 constituting one wall surface of the pressure chamber 152 (the upper surface in FIG. 5), the individual electrode 157 is disposed at a position corresponding to each pressure chamber 152 (a position facing the pressure chamber 152 with the vibration plate 156 interposed therebetween). The piezoelectric element 158 provided with is provided. The diaphragm 156 is made of a conductive material such as SUS, and also serves as a common electrode for the plurality of piezoelectric elements 158 disposed corresponding to the pressure chambers 52. It is also possible to form the diaphragm with a non-conductive material such as resin. In this case, a common electrode layer made of a conductive material such as metal is formed on the surface of the diaphragm member. For the piezoelectric element 158, a piezoelectric material such as lead zirconate titanate, barium titanate, or lead titanate is preferably used. Among these, lead zirconate titanate (PZT) is particularly preferable because of its excellent piezoelectric characteristics such as piezoelectric constant and high frequency response.

  When a drive voltage is applied to the piezoelectric element 158 in a state where the pressure chamber 152 is filled with ink, the volume of the pressure chamber 152 changes due to the deformation of the vibration plate 156 accompanying the displacement of the piezoelectric element 158, and the pressure change accompanying this change. As a result, ink is ejected from the nozzle 151. When the displacement of the piezoelectric element 158 returns to its original state after ink ejection, new ink is refilled into the pressure chamber 152 from the common channel 155 through the supply port 154.

  In the present embodiment, a method (piezoelectric method) that ejects ink by using the displacement of the piezoelectric element 158 is employed. However, the ink ejection method is not particularly limited in the implementation of the present invention, and a heater It is possible to employ a thermal method and other various methods in which ink is heated by a heating element such as bubbles to generate bubbles and ink is ejected at that pressure.

<Control system configuration>
Next, the control system of the inkjet recording apparatus 100 will be described.

  FIG. 6 is a principal block diagram showing a control system of the inkjet recording apparatus 100. The inkjet recording apparatus 100 includes a communication interface 170, a system controller 172, an image memory 174, a motor driver 176, a heater driver 178, a print control unit 180, an image buffer memory 182, a head driver 184, and the like.

  The communication interface 170 is an interface unit that receives image data sent from the host computer 186. A serial interface or a parallel interface can be applied to the communication interface 170. In this part, a buffer memory (not shown) for speeding up communication may be mounted.

  Image data sent from the host computer 186 is taken into the inkjet recording apparatus 100 via the communication interface 170 and temporarily stored in the image memory 174. The image memory 174 is a storage unit that temporarily stores an image input via the communication interface 170, and data is read and written through the system controller 172. The image memory 174 is not limited to a memory composed of semiconductor elements, and a magnetic medium such as a hard disk may be used.

  The system controller 172 is a control unit that controls the communication interface 170, the image memory 174, the motor driver 176, the heater driver 178, and the like. The system controller 172 includes a central processing unit (CPU) and its peripheral circuits, and performs communication control with the host computer 186, read / write control of the image memory 174, and the like, and a transport motor 188 and heater 189. A control signal for controlling is generated.

  The motor driver 176 is a driver (drive circuit) that drives the motor 188 in accordance with an instruction from the system controller 172. The heater driver 178 is a driver that drives the heater 189 of the post-drying unit 142 and other units in accordance with an instruction from the system controller 172.

  The print control unit 180 has a signal processing function for performing various processes such as processing and correction for generating a print control signal from the image data in the image memory 174 in accordance with the control of the system controller 172. The control unit supplies a control signal (dot data) to the head driver 184. Necessary signal processing is performed in the print control unit 180, and the ejection amount and ejection timing of the ink droplets of the recording head 150 are controlled via the head driver 184 based on the image data. Thereby, a desired dot size and dot arrangement are realized.

  The print control unit 180 includes an image buffer memory 182, and image data, parameters, and other data are temporarily stored in the image buffer memory 182 when image data is processed in the print control unit 180. In FIG. 6, the image buffer memory 182 is shown in a form associated with the print control unit 180, but it can also be used as the image memory 174. Also possible is an aspect in which the print controller 180 and the system controller 172 are integrated and configured with one processor.

  The head driver 184 generates a drive signal for driving the piezoelectric elements 158 (see FIG. 5) of the recording heads 150 for each color based on the dot data given from the print control unit 180, and the drive signal generated for the piezoelectric elements 158. Supply. The head driver 184 may include a feedback control system for keeping the driving conditions of the recording head 150 constant.

  As described with reference to FIG. 2, the print detection unit 124 is a block including a line sensor. The print detection unit 124 reads an image printed on the recording paper 116, performs necessary signal processing, and the like to perform a print status (whether ejection is performed, droplet ejection). And the detection result is provided to the print control unit 180.

  The print control unit 180 performs various corrections on the recording head 150 based on information obtained from the print detection unit 124 as necessary.

  Next, the present invention will be specifically described with reference to examples, but the present invention is not limited to these examples.

[Production of head]
Seven types of heads A to G having different nozzle shapes were manufactured. Details of the nozzle shape of each of the heads A to G are shown in FIG. Each of the heads A to G has the same configuration except that the nozzle shape is different, and a piezoelectric head 150 as shown in FIG. 5 is applied.

  In addition, the “cylindrical nozzle” in FIG. 7 refers to a nozzle consisting only of a portion corresponding to the cylindrical portion 10a (see FIG. 1) of the funnel-shaped nozzle 10 of the present invention. Specifically, as shown in FIG. The nozzle 92 is configured with a predetermined spread angle (taper angle) θ from the ink discharge side to the ink inflow side.

<Manufacturing method of nozzle plate>
The manufacturing method of the nozzle plate provided in each of the heads A to G is as follows. Each nozzle plate is denoted by the same reference numeral (A to G) as the corresponding head, and for example, the head A is provided with the nozzle plate A, and the head B is provided with the nozzle plate B. .

(1) Nozzle plate A
A fluororesin and a fluoroalkylsilane are formed on one side of a 75 μm thick polyimide plate (Ube Industries Upilex) on a silicon resin layer formed of a silane coupling agent and an alkoxysilane compound by the method described in JP-A-11-263020. An ink repellent film composed of a fluororesin layer was formed using the compound.

  Next, an adhesive tape made of polyethylene terephthalate was attached on the ink repellent film for protection. From the side opposite to the adhesive tape side of this polyimide plate, 256 nozzle holes with a diameter of 20 μm on the discharge side were punched at an interval of 150 dpi (170 μm interval) by an excimer laser. At this time, a cylindrical nozzle hole having a small taper angle of 5 degrees was formed by keeping the laser diameter (beam diameter) constant during processing with an excimer laser.

(2) Nozzle plate B
At the time of drilling with an excimer laser, first, after drilling a conical hole having a taper angle of 20 degrees to a depth of 60 μm by the method described in Japanese Patent Application Laid-Open No. 2005-153260, And a conical hole having a taper angle of 5 degrees and a conical part having a taper angle of 20 degrees to form a funnel-shaped nozzle.

(3) Nozzle plates CG
Nozzle plates C to G were manufactured by the same method as that for nozzle plate B. At that time, the nozzle plates C, D, and F were manufactured by changing the taper angles of the conical portions to 30 degrees, 70 degrees, and 75 degrees, respectively. The nozzle plates F and G were manufactured by adjusting the laser diameter so that the discharge side opening diameters of the nozzle holes were 30 μm and 35 μm, respectively.

[Preparation of ink]
<Preparation of pigment ink>
After mixing a pigment, an organic solvent, water, and a pigment dispersant with the combination shown in FIG. 8, each pigment dispersion was prepared by dispersing it with a zirconia bead having a diameter of 1 mm in a bead mill, and then the zirconia beads were removed. To this pigment dispersion, an addition amount of a surfactant (added to some inks) and an antibacterial agent shown in FIG. 8 were added and mixed well. Subsequently, this liquid was subjected to filtration and membrane deaeration treatment using a hollow fiber membrane to prepare pigment inks 1 to 12.

  In addition, each addition amount of FIG. 8 represents a mass part, respectively.

  In FIG. 8, the details of each additive described in abbreviations are as follows.

<Non-aqueous solvent>
DEG: Diethylene glycol DPGME: Dipropylene glycol monomethyl ether TEGBE: Triethylene glycol monobutyl ether <Colorant: Pigment>
Pigment 1: C.I. I. Pigment Red 122
Pigment 2: C.I. I. Pigment Blue 15: 4
<Pigment dispersant>
Zirconia beads <Surfactant>
Surfinol 104 (manufactured by Air Products)
<Anti-binder>
Proxel: manufactured by Avicia [Inkjet image recording]
Using a single-pass ink jet recording apparatus (printing width: 2 inches, resolution: 1200 dpi) that can replace the head, the manufactured head and ink were evaluated by printing and discharging tests under the following conditions.

  When an appropriate amount of liquid discharged using the prepared ink was measured, an appropriate amount of liquid discharged from each nozzle of the heads A to E was 2 to 2.6 pl, and an appropriate amount of liquid discharged from the nozzle of the head F was 2. The appropriate amount of liquid discharged from the nozzle of the head G was 3.8 to 4.1 pl.

<Evaluation of curling characteristics after printing>
Using the inkjet recording apparatus, a solid image of 45 mm × 70 mm was printed at a resolution of 1200 dpi × 1200 dpi on high quality paper (C2 paper manufactured by Fuji Xerox Co., Ltd.) cut to 70 mm × 90 mm. Next, this printed plain paper is left on a flat table on a flat table in an environment of 25 ° C. and 30% RH for one week, and the height from the table to the edge is measured. Curl characteristics were evaluated according to the criteria.

  A: Almost flat and no curling is observed.

  ◯: The end float is 5 mm or less, and a slight curl is recognized.

  (Triangle | delta): Curling is recognized when the float of an edge part is 5 mm or more and 10 mm or less.

  X: The rising height of the most floating part in the four corners is 10 mm or more, and curling is recognized.

  XX: It is rounded into a cylindrical shape and cannot be measured.

<Evaluation of character quality>
On the same plain paper as above, print Chinese characters in 4-point, 5-point and 6-point MS Mincho style with a recording resolution of 1200 x 1200 dpi, visually observe the printed character image, and follow the evaluation criteria below. The quality was evaluated.

  A: A 4-point character image is legible.

  ○: It is difficult to interpret a 4-point character image, but a 5-point character image can be interpreted.

  Δ: Although it is difficult to interpret 4, 5 point character images, it is possible to interpret 6 point character images.

  X: It is difficult to interpret the character image by 6 points.

<Evaluation of long-term discharge suitability>
Under the environment of 23 ° C. and 30% RH, a solid image having a width of 45 mm and a height of 40 mm was continuously printed for 30 minutes without head maintenance using the inkjet recording apparatus. At this time, the print after 30 minutes was visually evaluated according to the following evaluation criteria.

  A: Image unevenness is not confirmed.

  ○: Slight image unevenness with no directivity is observed.

  Δ: Unevenness in the paper conveyance direction is observed.

  X: One white streak in the paper transport direction is observed.

  XX: Two or more white stripes are generated.

  Each evaluation result obtained by the above is shown in FIGS.

  As is apparent from the results of FIGS. 9 to 11, when drawing is performed using the funnel-shaped nozzle to which the present invention is applied and ink-jet ink, the curl after printing and the character quality are excellent, and fine liquid discharge of 3 pl or less is possible. The nozzles are less likely to be chipped when continuously ejected for a long time.

  As described above, according to the present embodiment, by using the aqueous ink having a high ratio of the high boiling point aqueous solvent, the fine droplet is ejected from the funnel-shaped nozzle including the cylindrical portion and the conical portion having the taper angle within a predetermined range. In the present invention, ejection stability is improved without causing nozzle ejection defects (such as non-ejection), curling / cuckling of the recording medium can be suppressed, and high-resolution image recording on the recording medium becomes possible. It was confirmed that an effect was obtained.

  The inkjet recording method and the inkjet recording apparatus of the present invention have been described in detail above, but the present invention is not limited to the above examples, and various improvements and modifications are made without departing from the gist of the present invention. Of course it is also good.

Sectional view showing the nozzle shape of the present invention Overall configuration diagram showing outline of inkjet recording apparatus Main part plan view showing the periphery of the printing unit of the ink jet recording apparatus Plane perspective view showing structure example of recording head Sectional view showing the three-dimensional structure of the recording head Main block diagram showing the system configuration of the inkjet recording apparatus The figure which showed the nozzle shape of each recording head used in an Example The figure which showed the composition of each ink used in an Example Figure showing the evaluation results of inkjet image recording Figure showing the evaluation results of inkjet image recording Figure showing the evaluation results of inkjet image recording Cross section showing a trumpet nozzle Sectional view showing a cylindrical nozzle

Explanation of symbols

  DESCRIPTION OF SYMBOLS 10 ... (funnel-shaped) nozzle, 10a ... Cylindrical part, 10b ... Conical part, 12 ... Nozzle plate, 100 ... Inkjet recording apparatus, 150 ... Recording head, 151 ... Nozzle, 152 ... Pressure chamber, 155 ... Common flow path, 156 ... Vibration plate, 158 ... Piezoelectric element, 160 ... Nozzle plate

Claims (8)

Containing a pigment and water, and having the following general formula (I)

(Where n is 2 or 3, R ₁ is an alkyl group having 1 to 4 carbon atoms, R ₂ is hydrogen or a methyl group, and R ₃ is hydrogen or an acetyl group.) Using an inkjet ink containing 50% by mass or more and less than 80% by mass with respect to
A cylindrical portion having a spread angle of 0 ° to 10 ° from the opening on the ink ejection side toward the ink inflow side, and a cylindrical portion disposed on the ink inflow side of the cylindrical portion, and 30 ° to 70 ° toward the ink inflow side. An ink jet recording method, wherein a droplet of 3 pl or less is ejected from a funnel-like nozzle composed of a conical portion having a spreading angle of.   The inkjet recording method according to claim 1, wherein a droplet of 2 pl or less is discharged from the funnel-shaped nozzle.   3. The ink jet recording method according to claim 1, wherein an opening diameter of the funnel-shaped nozzle on the ink discharge side is 30 [mu] m or less.   The inkjet recording method according to any one of claims 1 to 3, wherein recording is performed on plain paper.   5. The ink jet recording method according to claim 1, wherein recording is performed using a line head in which the funnel-shaped nozzles are arranged over a length corresponding to the width of the recording medium. A cylindrical portion having a spread angle of 0 ° to 10 ° from the opening on the ink ejection side toward the ink inflow side, and a cylindrical portion disposed on the ink inflow side of the cylindrical portion, and 30 ° to 70 ° toward the ink inflow side. A discharge means having a funnel-shaped nozzle composed of a conical portion having a spread angle of
The discharge means contains a pigment and water, and has the following general formula (I)

(Where n is 2 or 3, R ₁ is an alkyl group having 1 to 4 carbon atoms, R ₂ is hydrogen or a methyl group, and R ₃ is hydrogen or an acetyl group.) An ink jet recording apparatus, characterized in that it is means for ejecting ink jet ink containing 50 mass% or more and less than 80 mass% as droplets of 3 pl or less from the funnel-shaped nozzle. The discharge means includes a nozzle forming member on which the funnel-shaped nozzle is formed,
The inkjet recording apparatus according to claim 6, wherein the nozzle forming member is made of polyimide.   8. The ink jet recording apparatus according to claim 6, wherein the ejection unit is a line head in which the funnel-shaped nozzles are arranged over a length corresponding to the width of the recording medium.

Images