JP2006089570A - Ink, ink set using the same, inkjet recording method and inkjet recording device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an ink satisfying inkjet recording characteristics, having good color reproducibility of black color, hardly causing discoloration even in an image formed on a coated paper, exhibiting high gas resistance and capable of providing a black image hardly causing bronzing phenomenon. <P>SOLUTION: The ink contains each coloring material represented by general formulae (I) and (II). <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to ink, in particular, ink that is ejected from an orifice in accordance with a recording signal and records on a recording medium, and can be suitably used for ink jet recording. The color tone is black, an ink set using the ink, and an ink jet recording method The present invention relates to an ink cartridge, a recording unit, and a recording apparatus.

  In recent years, the ink jet recording system has been widely used as a means for easily forming a color image, particularly in offices and personal use. The ink used in such an ink jet recording system has high storage stability, does not cause clogging of the discharge orifice, and causes inconveniences such as rubbing on the recorded image at the start of recording after standing for a long time or after standing for a long time. The performance for adapting to the recording system is required. Furthermore, quality performance with respect to a recorded image is required, such as excellent color tone reproducibility when an image is formed, and an image having a high optical density and a clear color tone.

  Of the inks used in the ink jet recording system, black ink is an important ink that is used for full-color images as well as mono-color images. Examples of the dye used in these black inks include C.I. I. Various types of structural dyes have been used, including Food Black 2 (see, for example, Patent Document 1).

By the way, in recent years, image quality improvement of inkjet recording images has progressed, and it has become possible to realize high-quality recording images comparable to silver salt photographs. Therefore, a higher level of recorded image performance is required for inkjet recorded images, and of course the image quality can cause a thigh color with respect to sunlight or various illumination lights. Image fastness such as excellent light resistance that does not cause discoloration to oxidizing gases (ozone, NO _x , SO _x, etc.) contained in trace amounts in the atmosphere is also required. It has come to be.

  Conventionally, image fastness has been mainly regarded as a problem of fading due to sunlight or various illumination lights, and the problem of fading has been solved by selecting a dye having excellent light resistance. However, recently, in addition to the problem of image fading, the problem of image discoloration has been highlighted. That is, the conventional ink image has the problem of discoloration in addition to the problem of fading. Here, the discoloration means that the hue does not change much but the hue changes.

Of the color inks, the problem that the black image is changed to brown, particularly in black ink, is important. In the case of a full-color image, the image quality sharply deteriorates due to the discoloration of the black image. The problem of discoloration in the black image is greatly affected by oxidizing gas (ozone, NO _x , SO _x, etc.) contained in a minute amount in the atmosphere, and proceeds even in an environment where there is no sunlight or various illumination lights. In particular, in the case of so-called coated paper in which an ink receiving layer containing a pigment and a binder is formed on a base material such as paper in order to increase the sharpness, color tone reproducibility and optical density of the ink, Therefore, even if an ink with little problem of discoloration is used, significant discoloration occurs. Therefore, improvement in gas resistance of an image is desired.

For this technical problem, color tone and discoloration resistance against ozone gas have been improved (see, for example, Patent Document 2 and Patent Document 3), but a high-quality recorded image comparable to a silver salt photograph is obtained. In recent ink jet recording systems that can be used, there is still a need for further improvements in the color tone and gas resistance of black ink.
In black inks containing water-soluble black dyes, the color developability is reduced due to the aggregation of the dyes. May have a significant impact.

JP 59-93766 A Japanese Patent No. 0219615 Japanese Patent Publication No. 8-26263

  Therefore, the object of the present invention is to satisfy the performance required for ink jet recording inks, have good black color reproducibility when images are formed on various recording media, and even for images formed on coated paper. An object of the present invention is to provide a (black) ink that does not cause a problem of discoloration, can give high gas resistance to an image, and can give a good image without causing bronzing.

  Another object of the present invention is to provide a recording method that has an excellent color tone, does not easily fade, and can obtain a good black image without causing a bronze phenomenon. There is. Furthermore, an object of the present invention is to provide a recording unit, an ink cartridge, an ink set, and an ink jet recording apparatus that can obtain the above-described excellent effects by using the (black) ink.

（上記一般式（Ｉ）中、Ｒ₁及びＲ₂は各々独立に、置換若しくは未置換の炭素数１〜４のアルキル基を表し、少なくともＲ₁及びＲ₂のうち何れかは、１つの水酸基を有する。Ｒ₃は、水素原子、或いは、置換若しくは未置換のフェニル基を表す。Ｘ₁は、カルボキシル基又はスルホン酸基、或いは、それらのアルカリ金属塩、アンモニウム塩、若しくは有機アンモニウム塩の何れかを表す。ｍは、１又は２の整数を表す。Ｍは、スルホン酸基の対イオンであり、アルカリ金属イオン、アンモニウムイオン或いは有機アンモニウムイオンの何れかを表す。）

（上記一般式（II）中、Ｒ₄、Ｒ₅及びＲ₆は各々独立に、炭素数１〜４のアルキル基を表す。Ｒ₇は、水素原子、或いは、置換若しくは未置換のフェニル基を表す。Ｘ₂は、カルボキシル基又はスルホン酸基、或いは、それらのアルカリ金属塩、アンモニウム塩、若しくは有機アンモニウム塩の何れかを表す。ｎは、１又は２の整数を表す。ｐ及びｑは各々独立に、０又は１の整数を表し（０の場合の置換基は水素原子）、ｐ＋ｑは１若しくは２である。Ｍは、スルホン酸基の対イオンであり、アルカリ金属イオン、アンモニウムイオン或いは有機アンモニウムイオンの何れかを表す。） The above object is achieved by the present invention described below. That is, the present invention is an ink comprising at least a color material represented by the following general formula (I) and a color material represented by the following general formula (II).

(In the general formula (I), R ₁ and R ₂ each independently represents a substituted or unsubstituted alkyl group having 1 to 4 carbon atoms, and at least _one of R ₁ and R ₂ is one hydroxyl group. R ₃ represents a hydrogen atom or a substituted or unsubstituted phenyl group, and X ₁ is a carboxyl group or a sulfonic acid group, or an alkali metal salt, ammonium salt or organic ammonium salt thereof. M represents an integer of 1 or 2. M is a counter ion of a sulfonic acid group, and represents any one of an alkali metal ion, an ammonium ion, or an organic ammonium ion.)

(In the general formula (II), R ₄ , R ₅ and R ₆ each independently represents an alkyl group having 1 to 4 carbon atoms. R ₇ represents a hydrogen atom or a substituted or unsubstituted phenyl group. X ₂ represents a carboxyl group or a sulfonic acid group, or an alkali metal salt, an ammonium salt, or an organic ammonium salt thereof, n represents an integer of 1 or 2, and p and q each represent Independently, it represents an integer of 0 or 1 (the substituent in the case of 0 is a hydrogen atom), and p + q is 1 or 2. M is a counter ion of the sulfonic acid group and is an alkali metal ion, ammonium ion or organic (Represents any ammonium ion.)

  An ink jet recording method according to another aspect of the present invention includes a process of discharging the black ink according to each aspect of the present invention from an orifice according to a recording signal. In particular, an ink set is used in which at least one color ink selected from yellow ink, magenta ink, and cyan ink is combined with the black ink according to any one of the above-described embodiments. It is preferable.

  The recording unit according to the present invention includes an ink storage portion in which the black ink according to the present invention or each ink constituting the ink set according to the present invention is stored, and a head portion for discharging the ink. Is provided.

  In addition, the ink cartridge according to the present invention is provided with an ink storage portion that stores the ink according to the present invention described above or each ink constituting the ink set according to the present invention.

  An ink jet recording apparatus according to the present invention includes a recording unit including the ink according to the present invention or the ink storage portion storing the ink of the ink set according to the present invention, and a recording head for discharging the ink. It is characterized by comprising.

  According to the present invention, when printing on various recording papers, an ink that has a clear black tone, exhibits excellent gas resistance, and does not cause bronzing is obtained. A set, an ink jet recording method, a recording unit, an ink cartridge, and an ink jet recording apparatus are provided.

  Hereinafter, the present invention will be described in more detail with reference to preferred embodiments. In view of the above-described object, the present inventors have developed an ink in which a color material represented by the following general formula (I) and a color material represented by the following general formula (II) are combined in the course of various studies on the composition of the ink. This ink and images formed with this ink were evaluated. As a result, this ink has an excellent tint that can be used for photographic image formation, and the image formed by the ink is extremely excellent in gas resistance, and the image is discolored and bronzing phenomenon. The inventors have found that the above-described object can be achieved without causing any problems, and have made the present invention.

[First Embodiment]
(Color material)
The ink according to an embodiment of the present invention includes a color material and an aqueous medium. As the color material, the first color material represented by the general formula (I) described below, and the general formula (II) The second color material represented by the above is used in combination. Hereinafter, each of the first color material and the second color material will be described. An image obtained by the ink according to the present invention containing the first and second colorants represented by the following general formulas (I) and (II) exhibits a very excellent color tone, and is further resistant to ozone. Excellent in properties and does not cause bronzing.

（上記一般式（Ｉ）中、Ｒ₁及びＲ₂は各々独立に、置換若しくは未置換の炭素数１〜４のアルキル基を表し、少なくともＲ₁及びＲ₂のうち何れかは、１つの水酸基を有する。Ｒ₃は、水素原子、或いは、置換若しくは未置換のフェニル基を表す。Ｘ₁は、カルボキシル基又はスルホン酸基、或いは、それらのアルカリ金属塩、アンモニウム塩、若しくは有機アンモニウム塩の何れかを表す。ｍは、１又は２の整数を表す。Ｍは、スルホン酸基の対イオンであり、アルカリ金属イオン、アンモニウムイオン或いは有機アンモニウムイオンの何れかを表す。） <First coloring material>

(In the general formula (I), R ₁ and R ₂ each independently represents a substituted or unsubstituted alkyl group having 1 to 4 carbon atoms, and at least _one of R ₁ and R ₂ is one hydroxyl group. R ₃ represents a hydrogen atom or a substituted or unsubstituted phenyl group, and X ₁ is a carboxyl group or a sulfonic acid group, or an alkali metal salt, ammonium salt or organic ammonium salt thereof. M represents an integer of 1 or 2. M is a counter ion of a sulfonic acid group, and represents any one of an alkali metal ion, an ammonium ion, or an organic ammonium ion.)

As more preferable specific examples of R _{1 to} R _{3 in} the general formula (I), R ₁ and R ₂ each independently represents a substituted or unsubstituted alkyl group having 1 to 4 carbon atoms; Any _one of R ₁ and R ₂ has at least one hydroxyl group, and examples of the substituent of the alkyl group include a linear or branched alkoxyl group having 1 to 4 carbon atoms and an amino group. Or a halogen atom (fluorine, chlorine, bromine, etc.). Examples of R ₃ include a hydrogen atom, a substituted or unsubstituted phenyl group, and the like. Examples of the substituent of the phenyl group include a linear or branched alkyl group having 1 to 4 carbon atoms, a sulfonic acid group or a salt thereof, a carboxyl group or a salt thereof, and the like. Further, X ₁ in the above formula will be described in detail. Examples of X ₁ include —COOM and —SO ₃ M. At this time, M is an alkali metal (for example, Li, Na, etc.), ammonium (NH ₄ ), organic ammonium, or the like.

<Second color material>

(In the general formula (II), R ₄ , R ₅ and R ₆ each independently represents an alkyl group having 1 to 4 carbon atoms. R ₇ represents a hydrogen atom or a substituted or unsubstituted phenyl group. X ₂ represents a carboxyl group or a sulfonic acid group, or an alkali metal salt, an ammonium salt, or an organic ammonium salt thereof, n represents an integer of 1 or 2, and p and q each represent Independently, it represents an integer of 0 or 1 (the substituent in the case of 0 is a hydrogen atom), and p + q is 1 or 2. M is a counter ion of the sulfonic acid group and is an alkali metal ion, ammonium ion or organic (Represents any ammonium ion.)

Examples of R ₇ in the general formula (II) include a hydrogen atom and a substituted or unsubstituted phenyl group. Examples of the substituent of the phenyl group include a linear or branched alkyl group having 1 to 4 carbon atoms, a sulfonic acid group or a salt thereof, a carboxyl group or a salt thereof, and the like. Examples of X ₂ include —COOM and —SO ₃ M. At this time, M is an alkali metal (for example, Li, Na, etc.), ammonium (NH ₄ ), organic ammonium, or the like.

<Specific example of the first coloring material>
Specific examples of the first coloring material represented by the general formula (I) that can be suitably used in the present invention include the following exemplified compounds 1 to 5. Further, two or more kinds of color materials represented by the general formula (I) listed below may be used at the same time. However, the first coloring material used in the present invention is not limited to these, and for example, a compound having a structure described in International Publication No. 00/43451 can be used. .

<Specific example of the second coloring material>
Although the 2nd coloring material used for this invention is a compound represented by above-described general formula (II), the following exemplary compounds 6-9 can be mentioned as the specific example. The second color material used in the present invention is not limited to these. In the ink according to the present invention, two or more kinds of color materials as listed below may be used simultaneously.

  The amount of the first color material represented by the general formula (I) and the second color material represented by the general formula (II) contained in the ink according to the above-described form is the general formula (I). It is preferable that the ratio of the first color material represented by: The second color material represented by the general formula (II) is in the range of 8: 2 to 2: 8 on a mass basis. The image obtained by the ink mixed at such a mass ratio is obtained by combining and using these first color material and second color material, and has a clear color tone and sufficient image density. Further, the remarkable effect of the present invention, which shows further excellent ozone resistance, is exhibited at a higher level. Further, the content of all the color materials in the ink is preferably in the range of 1.0 to 15.0% by mass, particularly 4.0 to 10.0% by mass with respect to the total amount of the ink.

(Aqueous medium)
The ink according to the present invention can be obtained by dissolving the above-described coloring material in an aqueous medium. As the aqueous medium, water or a mixed medium of water and a water-soluble organic solvent is used. The water-soluble organic solvent contained in the aqueous medium is not particularly limited as long as it shows water solubility. For example, alcohol, polyhydric alcohol, polyglycol, glycol ether, nitrogen-containing polar solvent, sulfur-containing polar solvent, etc. are used. it can. The content of these water-soluble organic solvents is 1 to 40 in the whole ink in consideration of maintaining the moisture retention of the ink, improving the solubility of the coloring material, and effectively penetrating the ink into the recording paper (recording medium). It is preferable to set it as the range of mass%, More preferably, it is set as the range of 3-30 mass%. In addition, the content of water in the ink is good because the colorant dye has good solubility in ink, has a viscosity for stable ink ejection, and does not cause clogging at the nozzle tip. Is preferably in the range of 30 to 95% by mass.

(Additive)
In order to maintain the moisturizing property of the ink, in the ink according to the present invention, a moisturizing solid content such as urea, a urea derivative, trimethylolpropane or the like may be used as an ink component, if necessary. In general, the content of moisturizing solids such as urea, urea derivatives, and trimethylolpropane in the ink is preferably in the range of 0.1 to 20.0% by mass, more preferably, based on the total amount of the ink. It is the range of 3.0-10.0 mass%. Furthermore, in addition to the above components, the ink according to the present invention includes a surfactant, a pH adjuster, a rust inhibitor, an antiseptic, an antifungal agent, an antioxidant, an anti-reduction agent, and an evaporation accelerator as necessary. Various additives such as a chelating agent and a water-soluble polymer may be contained.

[Second Embodiment]
The ink according to the second embodiment of the present invention includes a third color material in addition to the configuration of the ink containing the first and second color materials according to the first embodiment described above. As an ink containing a yellow dye. By adding a yellow dye as the third color material, the obtained image becomes a black ink that exhibits a more excellent color tone and further exhibits excellent gas resistance (ozone resistance).

  In particular, as a yellow dye which is a third color material, C.I. I. Direct Yellow 86 and C.I. I. The color tone of the image obtained by the ink of the aspect containing at least one of the Direct Yellow 132 is excellent. Such an ink according to the second embodiment of the present invention capable of forming an image having a more excellent color tone and a high ozone resistance is, for example, a silver that is particularly required to reproduce a delicate color tone. As a black ink for an ink jet printer for printing a high-quality image comparable to a salt photograph, it can be used very suitably.

  In the ink according to the second embodiment of the present invention, the amount (A) of the first color material represented by the general formula (I) and the second color represented by the general formula (II). The ratio between the amount (B) of the color material and the amount (C) of the yellow dye, which is the third color material, is as follows: the amount (A) of the first color material and the second color material The ratio of the mass of the yellow dye, which is the third coloring material, to the total mass of the amount (B) is adjusted to a range of (A + B): C = 99: 1 to 80:20. Is preferred. A more preferable range is (A + B): C = 98: 2 to 85:15. An image formed by an ink in which the first to third color materials are combined in such a range achieves a very clear color tone, a high image density, and sufficient gas resistance. .

  The ink according to the present invention described above exhibits a black color, but when combined with at least one color ink selected from a yellow ink, a magenta ink, and a cyan ink to form an ink set, and using this, an image is formed. Color reproducibility is good, no discoloration problem occurs in images formed on coated paper, high gas resistance can be given to the image, and a good image without bronzing can be obtained. It is done.

  The ink or ink set according to the present invention described above is particularly preferably used in an ink jet recording method in which recording is performed by ejecting droplets by the action of thermal energy, but can also be used as another ink jet recording method or a general writing instrument. Needless to say, it can be used. Hereinafter, these will be described.

[Recording device, ink cartridge, recording unit]
As a recording apparatus suitable for recording using the ink according to the present invention described above, heat corresponding to the recording signal is applied to the ink in the chamber of the recording head having the ink storage portion in which these inks are stored. Examples thereof include an apparatus that applies energy and generates ink droplets by the energy.

  1 to 3 show a configuration example of a recording head that is a main part of the recording head. The head 13 is a heat generating head 15 having a glass, ceramic, or plastic plate having a groove 14 through which ink passes and a heat generating resistor used for thermal recording (the head is shown in the figure, but is not limited thereto). It is obtained by adhering The heat generating head 15 includes a protective film 16 formed of silicon oxide or the like, aluminum electrodes 17-1 and 17-2, a heat generating resistor layer 18 formed of nichrome or the like, a heat storage layer 19, a substrate with good heat dissipation such as alumina. It consists of twenty.

  The ink 21 is filled up to the discharge orifice (fine hole) 22, and a meniscus 23 is formed by the pressure P. When a pulsed electric signal is applied to the electrodes 17-1 and 17-2 of the head 13, the region (heater) indicated by n of the heating element substrate 15 is rapidly heated, and the ink in contact with the surface is heated. Bubbles are generated in the nozzle 21, and the meniscus 23 is discharged by the pressure. The ink 21 is discharged through the nozzle 14 of the head, becomes an ink droplet from the discharge orifice 22, and flies toward the recording material. FIG. 3 shows an external view of an example of a multi-head in which a large number of heads shown in FIG. 1 are arranged. This multi-head is made by adhering a glass plate 27 having multi-nozzles 26 and a heating head 28 similar to that described in FIG.

  FIG. 4 shows an example of an ink jet recording apparatus incorporating this head. In FIG. 4, 61 is a blade as a wiping member, one end of which is held by a blade holding member to become a fixed end and form a cantilever. The blade 61 is disposed at a position adjacent to the recording area by the recording head, and in the case of the example shown in FIG. 4, it is held in a form protruding in the moving path of the recording head. Reference numeral 62 denotes a cap, which is disposed at a home position adjacent to the blade 61 and moves in a direction perpendicular to the moving direction of the recording head so as to come into contact with the ejection surface and perform capping. Further, reference numeral 63 in FIG. 4 denotes an ink absorber provided adjacent to the blade 61 and, like the blade 61, is held in a form protruding in the moving path of the recording head.

  The blade 61, the cap 62, and the absorber 63 constitute a discharge recovery portion 64, and the blade 61 and the absorber 63 remove moisture, dust, dust, and the like from the ink discharge port surface.

  Reference numeral 65 denotes a recording head that has discharge energy generating means and performs recording by discharging ink onto a recording material facing the discharge port surface on which the discharge ports are arranged. Reference numeral 66 denotes a recording head 65 having the recording head 65 mounted thereon. It is a carriage for performing the movement. The carriage 66 is slidably engaged with the guide shaft 67, and a part of the carriage 66 is connected to a belt 69 driven by a motor 68 (not shown). Accordingly, the carriage 66 can move along the guide shaft 67, and the recording area by the recording head 65 and its adjacent area can be moved.

  Reference numeral 51 denotes a paper feed unit for inserting a recording material, and 52 denotes a paper feed roller driven by a motor (not shown). With these configurations, a recording material is fed to a position facing the ejection port surface of the recording head, and is discharged to a paper discharge unit provided with a paper discharge roller 53 as recording progresses.

  In the above configuration, when the recording head 65 returns to the home position due to the end of recording or the like, the cap 62 of the head recovery unit 64 is retracted from the moving path of the recording head 65, but the blade 61 protrudes into the moving path. As a result, the ejection port surface of the recording head 65 is wiped. When the cap 62 is in contact with the ejection surface of the recording head 65 to perform capping, the cap 62 moves so as to protrude into the moving path of the recording head.

  When the recording head 65 moves from the home position to the recording start position, the cap 62 and the blade 61 are at the same position as that at the time of wiping described above. As a result, even in this movement, the ejection port surface of the recording head 65 is wiped. The above-mentioned movement of the recording head to the home position is performed not only at the end of recording or at the time of recovery of ejection, but also to the home position adjacent to the recording area at a predetermined interval while the recording head moves the recording area for recording. In accordance with this movement, the wiping is performed.

  FIG. 5 is a cross-sectional view showing an example of an ink cartridge 45 that contains ink supplied to the head via an ink supply member, for example, a tube. Here, reference numeral 40 denotes an ink container, for example, an ink bag, in which supply ink is stored, and a rubber plug 42 is provided at the tip thereof. By inserting a needle (not shown) into the stopper 42, the ink in the ink bag 40 can be supplied to the head. An ink absorber 44 receives waste ink.

  The ink jet recording apparatus according to the present invention is not limited to the one in which the head and the ink cartridge as described above are separated, and an apparatus in which they are integrated as shown in FIG. 6 is also preferably used. In FIG. 6, reference numeral 70 denotes a recording unit, in which an ink storage portion that stores ink, for example, an ink absorber is stored, and the ink in the ink absorber has a plurality of orifices. 71 is ejected as ink droplets. Reference numeral 72 denotes an atmosphere communication port for communicating the inside of the recording unit with the atmosphere. The recording unit 70 is used in place of the recording head 65 shown in FIG. 4 and is detachable from the carriage 66.

  Next, another specific example of the recording apparatus and the recording head according to the present invention will be described. FIG. 7 shows a main part of an example of a liquid discharge head as a discharge liquid discharge head that communicates bubbles with the atmosphere during discharge suitable for the present invention, and an ink jet printer as a liquid discharge apparatus using the liquid discharge head. It is a schematic perspective view shown. The ink jet printer shown in FIG. 7 has a conveying device 1030 for intermittently conveying a sheet 1028 as a recording material provided along the longitudinal direction in a casing 1008 in the direction indicated by the arrow P shown in FIG. A recording unit 1010 that is reciprocated along a guide shaft 1014 substantially parallel to a direction S substantially orthogonal to the conveyance direction P of the paper 1028 by the conveying device 1030, and a driving unit for reciprocating the recording unit 1010 And a moving drive unit 1006.

  The conveying device 1030 includes a pair of roller units 1022a and 1022b that are arranged to face each other substantially in parallel, a pair of roller units 1024a and 1024b, and a drive unit 1020 for driving each of these roller units. Yes. With this configuration, when the driving unit 1020 of the transport device 1030 is activated, the paper 1028 is sandwiched between the roller units 1022a and 1022b and the roller units 1024a and 1024b, and the direction of the arrow P shown in FIG. Are conveyed intermittently.

  Further, the movement drive unit 1006 is disposed substantially parallel to the belt 1016 wound around pulleys 1026a and 1026b disposed on the rotation shafts opposed to each other with a predetermined interval, and the roller units 1022a and 1022b, and the recording unit. The motor 1018 is configured to drive a belt 1016 coupled to a carriage member 1010a 1010 in the forward direction and the reverse direction.

  When the motor 1018 is activated and the belt 1016 rotates in the direction of arrow R in FIG. 7, the carriage member 1010a of the recording unit 1010 is moved by a predetermined amount of movement in the direction of arrow S in FIG. When the motor 1018 is activated and the belt 1016 rotates in the direction opposite to the arrow R direction in FIG. 7, the carriage member 1010a of the recording unit 1010 is predetermined in the direction opposite to the arrow S direction in FIG. Will be moved by the amount of movement. Further, a recovery unit 1026 for performing an ejection recovery process of the recording unit 1010 is opposed to the ink ejection port array of the recording unit 1010 at one end portion of the movement driving unit 1006 at a position serving as a home position of the carriage member 1010a. Is provided.

  In the recording unit 1010, inkjet cartridges (hereinafter simply referred to as cartridges) 1012Y, 1012M, 1012C, and 1012B are provided for each color, for example, for each of yellow, magenta, cyan, and black, a carriage member 1010a. Are detachably provided.

  FIG. 8 shows an example of an ink jet cartridge that can be mounted on the above-described ink jet recording apparatus. The cartridge 1012 in this example is of a serial type, and the main part is composed of an ink jet recording head 100 and a liquid tank 1001 for containing a liquid such as ink. The ink jet recording head 100 is formed with a large number of ejection ports 832 for ejecting a liquid, and a liquid such as ink is supplied from a liquid tank 1001 through a liquid supply passage (not shown) to a common liquid chamber ( (Not shown). A cartridge 1012 shown in FIG. 8 is formed by integrally forming an ink jet recording head 100 and a liquid tank 1001 so that liquid can be supplied into the liquid tank 1001 as necessary. A structure in which a liquid tank 1001 is connected to 100 in a replaceable manner may be adopted.

[Ink set]
The ink set according to the present invention is a combination of at least one of yellow ink, magenta ink, and cyan ink and the ink according to the present invention that exhibits the black color described above. Examples of the color material contained in each color ink of yellow, magenta, and cyan that can be used at that time include, for example, water-soluble xanthene series, triphenylmethane series, anthraquinone series, and monoazo series described in the color index. Bisazo, trisazo and tetrazo dyes can be preferably used.

  The ink set according to the present invention as described above is used in an ink jet recording apparatus having a recording unit provided with a storage unit for storing each ink constituting the ink set independently, an ink cartridge, or the like. . In the above description, the ink jet recording apparatus has been described by taking as an example a recording apparatus that ejects ink droplets by applying thermal energy to ink, but in addition, a piezoelectric ink jet recording apparatus that uses piezoelectric elements. But it can be used as well.

  Next, the present invention will be described in more detail with reference to examples and comparative examples. Unless otherwise specified, the ink components in Examples and Comparative Examples mean “parts by mass”.

<Examples 1-4>
The following components were mixed, sufficiently stirred and dissolved, followed by pressure filtration with a 0.20 μm filter to prepare inks of Examples 1 to 4, respectively.

(Ink composition of Example 1)
The above exemplified compound 1 represented by the general formula (I)
2.0 parts-the exemplified compound 6 represented by the general formula (II)
2.0 parts C.I. I. Direct Yellow 132
0.2 parts, glycerin 5.0 parts, urea 5.0 parts, ethylene glycol 10.0 parts, acetylenol EH (manufactured by Kawaken Fine Chemical Co., Ltd.)
0.5 parts, ethanol 5.0 parts, ion-exchanged water 70.3 parts

(Ink composition of Example 2)
-The exemplified compound 2 represented by the general formula (I)
2.4 parts-Exemplified Compound 7 represented by Formula (II)
1.6 parts C.I. I. Direct Yellow 86
0.5 parts, glycerin 5.0 parts, urea 5.0 parts, ethylene glycol 10.0 parts, acetylenol EH (manufactured by Kawaken Fine Chemical Co., Ltd.)
0.5 parts, ethanol 5.0 parts, ion-exchanged water 70.0 parts

(Ink composition of Example 3)
-The exemplified compound 3 represented by the general formula (I)
2.0 parts-the exemplified compound 8 represented by the general formula (II)
2.4 parts C.I. I. Direct Yellow 86
0.15 parts, glycerin 5.0 parts, urea 5.0 parts, ethylene glycol 10.0 parts, acetylenol EH (manufactured by Kawaken Fine Chemical Co., Ltd.)
0.5 parts, ethanol 5.0 parts, ion-exchanged water 69.05 parts

(Ink composition of Example 4)
-The exemplified compound 5 represented by the general formula (I)
2.2 parts-the exemplified compound 6 represented by the general formula (II)
2.2 parts, glycerin 5.0 parts, urea 5.0 parts, ethylene glycol 10.0 parts, acetylenol EH (manufactured by Kawaken Fine Chemical Co., Ltd.)
0.5 parts, ethanol 5.0 parts, ion-exchanged water 70.1 parts

<Comparative Examples 1-4>
The following components were mixed, sufficiently stirred and dissolved, followed by pressure filtration with a 0.20 μm filter to obtain inks of Comparative Examples 1 to 3, respectively.

(Ink composition of Comparative Example 1)
The above exemplified compound 4 represented by the general formula (I)
4.2 parts, glycerin 5.0 parts, urea 5.0 parts, ethylene glycol 10.0 parts, acetylenol EH (manufactured by Kawaken Fine Chemical Co., Ltd.)
0.5 parts, ethanol 5.0 parts, ion-exchanged water 70.3 parts

(Ink composition of Comparative Example 2)
The above exemplified compound 9 represented by the general formula (II)
4.0 parts, glycerin 5.0 parts, urea 5.0 parts, ethylene glycol 10.0 parts, acetylenol EH (manufactured by Kawaken Fine Chemical Co., Ltd.)
0.5 parts, ethanol 5.0 parts, ion-exchanged water 70.5 parts

(Ink composition of Comparative Example 3)
The above exemplified compound 6 represented by the general formula (II)
4.0 parts C.I. I. Direct Yellow 86
0.4 parts, glycerin 5.0 parts, urea 5.0 parts, ethylene glycol 10.0 parts, acetylenol EH (manufactured by Kawaken Fine Chemical Co., Ltd.)
0.5 parts, ethanol 5.0 parts, ion-exchanged water 70.1 parts

(Ink composition of Comparative Example 4)
・ C. I. Food Black 2 4.0 parts, glycerin 5.0 parts, urea 5.0 parts, ethylene glycol 10.0 parts, acetylenol EH (manufactured by Kawaken Fine Chemical Co., Ltd.)
0.5 parts, ethanol 5.0 parts, ion-exchanged water 70.5 parts

<Evaluation of ink>
Each of the inks of Examples 1 to 4 and Comparative Examples 1 to 4 of the present invention obtained above has an on-demand type multi-recording head that ejects ink by applying thermal energy corresponding to the recording signal to the ink. Each was mounted in a black ink storage portion of a color ink jet printer (BJ F850: manufactured by Canon Inc.) which is an ink jet recording apparatus, and the following (1) to (3) were evaluated according to the following methods and standards. Table 1 summarizes the color materials contained in the inks of Examples 1 to 4 and Comparative Examples 1 to 4, and the evaluation results obtained using these inks.

(1) Black reproducibility (color development)
The printer was filled with predetermined ink, and solid portions were printed on two types of recording materials, PPC paper (manufactured by Canon Inc.) and glossy paper (PR-101; manufactured by Canon Inc.). After printing, it was naturally dried for 24 hours, and the color tone of the subsequent image was visually observed and evaluated according to the following criteria.
A: A clear black color tone.
B: A color slightly different from a clear black (redness, blueness, greenness, etc.) is felt.
C: There is a sense of incongruity as a black color tone.

(2) Gas resistance (ozone resistance)
The above-described printer was filled with a predetermined ink, and a solid portion similar to that used in Evaluation (1) was printed on glossy paper (PR-101; manufactured by Canon Inc.). After that, the printed matter was naturally dried for 24 hours, and the printed matter was put in an ozone fade meter for 1 hour under the conditions of a tank temperature of 40 ° C., a relative humidity of 55%, and an ozone atmosphere of 3 ppm. The color difference between prints before and after the test, ΔE (CIE L ^* a ^* b ^* ), was measured by Gretag Spectrolino (trade name: manufactured by Gretag), and these measured values were evaluated according to the following criteria.

A: ΔE change amount is less than 15.
B: ΔE change amount is 15 or more and less than 20.
C: ΔE change amount is 20 or more.

(3) Bronze The above-mentioned printer was filled with a predetermined ink, and a solid portion similar to that used in evaluation (1) was printed on glossy paper (PR-101; manufactured by Canon Inc.). Thereafter, the printed matter was naturally dried for 24 hours, and the bronzing degree of the subsequent image was visually observed and evaluated according to the following criteria.
A: No bronze.
B: Some bronze is seen.
C: Bronze is conspicuous.

It is a longitudinal cross-sectional view of the head part of an inkjet recording device. It is a cross-sectional view of the head part of an inkjet recording device. It is an external appearance perspective view of the head part of an inkjet recording device. It is a perspective view which shows an example of an inkjet recording device. It is a longitudinal cross-sectional view of an ink cartridge. It is a perspective view of a recording unit. It is a schematic perspective view which shows the principal part of an example of the inkjet printer which can mount a liquid discharge head. It is a schematic perspective view showing an example of an ink jet cartridge provided with a liquid discharge head.

Explanation of symbols

13: head 14: ink groove 15: heating head 16: protective film 17-1, 17-2: aluminum electrode 18: heating resistor layer 19: heat storage layer 20: substrate 21: ink 22: ejection orifice (micropore)
23: Meniscus 24: Ink droplet 25: Recording medium 26: Multi-nozzle 27: Glass plate 28: Heat generating head 40: Ink bag 42: Plug 44: Ink absorber 45: Ink cartridge 51: Paper feed unit 52: Paper feed roller 53: Paper discharge roller 61: Blade 62: Cap 63: Ink absorber 64: Discharge recovery unit 65: Recording head 66: Carriage 67: Guide shaft 68: Motor 69: Belt 70: Recording unit 71: Head unit 72: Atmospheric communication Mouth 100: inkjet recording head 101: bubble 102: meniscus 1001: liquid tank 1006: moving drive unit 1008: casing 1010: recording unit 1010a: carriage member 1012: cartridge 1012Y, M, C, B: inkjet cartridge 1014: guide shaft 1016 : Belt 1018: Mo 1020: driving unit 1022a, 1022b: roller unit 1024a, 1024b: roller unit 1026: recovery unit 1026a, 1026b: pulley 1028: paper 1030: transport device P: paper transport direction R: belt rotation direction S: paper transport Direction approximately perpendicular to direction

Claims (11)

An ink comprising at least a color material represented by the following general formula (I) and a color material represented by the following general formula (II).

(In the general formula (I), R ₁ and R ₂ each independently represents a substituted or unsubstituted alkyl group having 1 to 4 carbon atoms, and at least _one of R ₁ and R ₂ is one hydroxyl group. R ₃ represents a hydrogen atom or a substituted or unsubstituted phenyl group, and X ₁ is a carboxyl group or a sulfonic acid group, or an alkali metal salt, ammonium salt or organic ammonium salt thereof. M represents an integer of 1 or 2. M is a counter ion of a sulfonic acid group, and represents any one of an alkali metal ion, an ammonium ion, or an organic ammonium ion.)

(In the general formula (II), R ₄ , R ₅ and R ₆ each independently represents an alkyl group having 1 to 4 carbon atoms. R ₇ represents a hydrogen atom or a substituted or unsubstituted phenyl group. X ₂ represents a carboxyl group or a sulfonic acid group, or an alkali metal salt, an ammonium salt, or an organic ammonium salt thereof, n represents an integer of 1 or 2, and p and q each represent Independently, it represents an integer of 0 or 1 (the substituent in the case of 0 is a hydrogen atom), and p + q is 1 or 2. M is a counter ion of the sulfonic acid group and is an alkali metal ion, ammonium ion or organic (Represents any ammonium ion.)   The mixing ratio of the color material represented by the general formula (I) and the color material represented by the general formula (II) is in the range of 8: 2 to 2: 8 on a mass basis. ink.   The ink according to claim 2, further comprising a yellow dye.   The ink according to claim 3, wherein the content of the yellow dye is 1 to 20% by mass in the content of all the color materials in the ink.   The yellow dye is C.I. I. Direct Yellow 86 and C.I. I. The ink according to claim 4, comprising at least one of Direct Yellow 132.   The ink according to claim 1, which is an ink used for ink jet recording.   7. The ink according to claim 1, wherein the black ink is an ink set in which at least one color ink selected from a yellow ink, a magenta ink, and a cyan ink is combined with a black ink. An ink set characterized by that.   An ink jet recording method having a process of discharging from an orifice in accordance with a recording signal, wherein the ink according to claim 6 or the ink set according to claim 7 is used.   The ink according to claim 6, wherein the ink accommodated in the ink accommodating portion is a recording unit provided with an ink accommodating portion in which ink is accommodated and a head portion for ejecting the ink. A recording unit comprising the ink of the ink set according to claim 7.   An ink cartridge, comprising: an ink storage unit that stores the ink according to claim 1 or the ink that constitutes the ink set according to claim 7.   A recording unit is provided that includes an ink storage portion that stores the ink according to claim 6 or the ink that constitutes the ink set according to claim 7, and a head portion that discharges the ink. An ink jet recording apparatus.

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