JP2006131667A - Aqueous fluorescent ink, forming method of recording image and recording image - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an aqueous ink which improves both fastness of images and color developing property of recording images, and to provide recording images and a recording method. <P>SOLUTION: The aqueous fluorescent ink is provided, which can form, in the center part, a first concentrated image of a first water-dispersive colorant containing a second water-soluble colorant and can form, in the whole circumference including the plane in the recorded material of the first concentrated image, a second concentrated image of the second water-soluble colorant. The aqueous fluorescent ink contains the first water-dispersive colorant, the second water-soluble colorant, a liquid medium dissolving or dispersing these, water and a surfactant which, being an ethylene oxide addition product of a higher alcohol and a liquid under the environment of 25°C, can dissolve the second water-soluble colorant in a relatively larger amount to the amount capable of dispersing the first water-dispersive colorant. Of the first water-dispersive colorant and the second water-soluble colorant at least one is a fluorescent colorant. The recording images and the recording method are also provided. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention is a color material configuration comprising a first water-dispersed color material and a second water-soluble color material, at least one of which includes a fluorescent color material, and the first water-dispersed color material and the second water-soluble color material The present invention relates to a recorded image forming method and a recorded image that can be used in an authenticity determination method by forming a separated state on a recording material, and an aqueous fluorescent ink used therefor. More specifically, a fixing unit in which a plurality of micro-aggregated first water-dispersed color materials are interspersed in the fixing portion of the second water-dissolving color material is formed on the recording material (fluorescent light emitting unit). It is related to a new correlation technique that separates the colored portion and improves fluorescence emission. Further, in the selected fluorescent color material, for the printing ink containing the first fluorescent color material that emits light of the reference wavelength used for measurement or determination among the wavelengths of fluorescence emitted by providing the reference excitation wavelength. The present invention relates to a novel technique for improving the fluorescence emission characteristics of the second fluorescent color material used in the above.

  Traditionally, water-soluble colorants have been used as the colorant for water-based inks, so that they have not only good reliability such as anti-sticking property and stability over time, but also anti-aggregation and anti-association properties of the colorant. There were many water-based inks that were also good and good in color development. On the other hand, generally, there are many cases where the fastness such as water resistance of the recorded image is not expected. In particular, with regard to fluorescence, good fluorescence is obtained because the solubility of the coloring material is good. However, when the concentration is increased, concentration quenching (the content of the coloring material is reduced to a certain amount). If it exceeds the upper limit, it could not be increased due to a phenomenon in which the fluorescence decreases. For example, US Pat. No. 6,176,908 (Patent Document 1) proposes an ink using a polymer dispersant, a pigment, and a fluorescent dye in combination.

  However, in the above proposal, a fluorescent dye is used. However, when an ink droplet is applied to a recording material, the polymer dispersant, the pigment, and the fluorescent dye are fixed in a fixed aggregate state (FIG. 2). Aggregation occurs in the entire system and the density of the recorded matter is improved, but the color developability including fluorescence is not as good as expected due to the concentration quenching.

  As a countermeasure, if it is limited to the PMU (one of the indicators indicating fluorescence intensity) described in the above proposal, a method of devising a printing area for measuring the fluorescence intensity can be considered. Difficult to do.

  In order to improve the water resistance, for example, a proposal has been made to use a coloring material in which a water-soluble group is a carboxylic acid. This proposal uses the dissociation characteristics of carboxylic acid, which is a water-soluble group, and when the pH of the ink is shifted to the acidic side on the recording material, the water solubility of the coloring material decreases and further aggregation occurs. Thus, the water resistance is improved.

  However, the above proposal has a problem that the coloring property of the coloring material is deteriorated because the water resistance is improved by the mechanism of aggregation and aggregation due to the decrease in water solubility of the coloring material. In particular, in the fluorescence emission, it has been difficult to improve the fluorescence due to the aggregation and association of the coloring materials.

  Further, as a means for improving the density of the recorded image by avoiding the above-described density quenching (a phenomenon in which the fluorescence decreases when the content of the color material exceeds a certain amount), a combination of a plurality of color materials is used. For example, WO02 / 092707 (Patent Document 2) discloses a method for improving the fluorescence emission property of a recorded material so that the absorption wavelength region of the color material used in combination with the material is not overlapped as much as possible. Proposed.

  In the above proposal, the fluorescence intensity can be improved to some extent and the density of the recorded image can be improved to some extent, but it is still insufficient for further improving the fluorescence intensity and the recorded image density. In WO02 / 092707 (Patent Document 2), the fastness of a recorded image is insufficient. For example, there is a sufficient need to improve the water resistance and light resistance of a recorded image.

  On the other hand, in recent years, for improving fastness such as water resistance and light resistance of recorded images, water-based inks using a combination of a water-dispersed color material such as carbon black and organic pigment and a colored resin containing a water-soluble color material have been used. Attempts have been made to use it. For example, in the water-based ink disclosed in JP-A-8-239610 (Patent Document 3), a water-dispersed color material is dispersed in an aqueous system by applying a resin to the water-dispersed color material. Etc. and used in ink. In WO02 / 092707 (Patent Document 2), a proposal using a pigment containing a fluorescent color material is made.

  When these inks are applied onto the recording material, water and liquid medium evaporate on the recording material, and permeate and diffuse into the recording material, thereby causing aggregation of water-dispersed color materials. The fastness of the recorded image, for example, water resistance and light resistance can be improved. Further, the water-soluble coloring material contained in the resin or the like provides good color development, particularly fluorescence emission, because the coloring material hardly aggregates and associates even when applied to the recording material. However, since a large amount of resin, emulsifier, etc. are used in the ink, the ink viscosity tends to increase. For example, if a large amount of the coloring material is used in the ink in order to improve the density of the recorded image, the recorded image is fixed. There is a tendency for dryness to deteriorate. Furthermore, the anti-sticking property is not preferable, and the pigment component tends to harden when left in a room temperature environment. For example, when used in an inkjet head, the water in the ink and the evaporation of the liquid medium are near the nozzle of the head. For example, the stable dispersion of the color material is broken, and the color materials are agglomerated with each other, which tends to cause fixation and clogging. Also, when used in an ink jet recording head that ejects ink droplets by applying thermal energy to ink, the color material dispersed on the heater is likely to adhere, greatly deteriorating the ink droplet ejection properties and impairing reliability. It becomes easy.

  In other words, the above proposal suggests that the water resistance and light resistance of the recorded matter are better than those of water-soluble dyes, but if the recording density of the image possessed by the recorded matter is increased, the fixing drying property and anti-sticking property of the recorded image are improved. It tends to get worse. In addition, for example, when the ink jet recording method is used, there is a case where clogging or ejection failure occurs.

  On the other hand, in recent years, inks that can be used in various applications have been demanded, and such applications are not limited to merely forming beautiful colored images. In addition, information such as symbols and barcodes is recorded on the recording material, and the fluorescent ink is colored to emit light by irradiating ultraviolet light of an appropriate wavelength, and information other than visible information (for example, security information) is given. Technology development has been proposed. In particular, in a method of reading authenticity determination (anti-counterfeiting) information and security information using a device that emits fluorescence and reads the emission intensity, excitation is performed at a reference wavelength (for example, 254 nm) used in the method (reference). Excitation wavelength), fluorescent color material is fluorescently colored and used for determination and measurement.

  On the other hand, when considering ink from the type of color material, it is easy to obtain a desired color tone when a dye is used as the color material, but the water resistance of the obtained image may be inferior. When a pigment is used as the coloring material, the water resistance of the obtained image is good, but the desired color tone may not be obtained. From such a viewpoint, as an ink that can give an image satisfying both the water resistance and the color tone, an ink containing both of them as a color material has been proposed. For example, Japanese Patent Publication No. 60-45669 (Patent Document 4) discloses that a water-soluble red dye (for example, Acid Red 52) and a red pigment are used as a recording agent, and these are dispersed in a liquid medium. A recording liquid containing the polymer dispersant is disclosed.

  For example, as a mailing system, it is common to perform fluorescent red printing in the United States, and a dye such as Acid Red 52 (AR52) also disclosed in the above publication is used as a fluorescent pigment. An ink containing Acid Red 52 as a fluorescent dye and a fluorescent dye, a pigment, and a polymer as a dispersant for the pigment is disclosed in US Pat. No. 6,176,908 (Patent Document 1). ing. In addition, as described in this specification, in order to change the formed “color tone” to a desired color tone (to adjust the color tone captured as a so-called human sense), a dye that matches the color tone It has been known as a design matter long before the description of Patent Document 1.

  The invention disclosed in US Pat. No. 6,176,908 (Patent Document 1) is applied to a fluorescent dye for the purpose of improving water resistance, as in Japanese Patent Publication No. 60-45669 (Patent Document 4). Although it is an invention related to an ink-jet ink to which a pigment is added, for the known purpose of visible (visual) color, a system combining two fluorescent dyes and further improving the fluorescence intensity (PMU value) The system to which the additive for is added is described. Specific examples of improving the fluorescence intensity (PMU value) include, in addition to the pigment portion (polymer, tetraethylene glycol or diethylene glycol), water as a solvent, 2-pyrrolidone, tetraethylene glycol, and the following plurality of fluorescent color materials Is described. Further, as the plural fluorescent color materials, any combination of AY7, AY73, DY96 with respect to the above-mentioned AR52 (0.4 mass%, 0.5 mass% to 3.0 mass%), basic violet (RHDB) ), An example of adding basic yellow (BY40) is described.

Japanese Patent Application Laid-Open No. 11-80632 (Patent Document 5) discloses an invisible fluorescent water-based ink comprising three types of fluorescent colorants (fluorescent whitening agent, coumarin derivative-based yellow fluorescent dye and rhodamine B, 6G-based). Ink containing red fluorescent dyes) and postcard printing by this are disclosed. According to the technical explanation, these three kinds of fluorescent color materials emit light at a peak due to ultraviolet light, and further, the light emission sequentially excites other color materials to finally emit 587 nm fluorescent light. However, in this document, there is no specific description about the excitation wavelength, and the technical explanation is made using the result that the ink and the recorded image show the same fluorescence characteristics. In general, the invention described in this document is not technically credible, judging from the fact that ultraviolet light is absorbed by water and the resulting fluorescence differs between ink and recorded image. Moreover, in WO02 / 092707 (Patent Document 2), as in the purpose of Patent Document 5, a plurality of fluorescent dyes (red dye, yellow dye, blue dye, black dye) that emit fluorescence by excitation with ultraviolet light are used. Ink is used to obtain a desired color light emission while forming a black image. In this document, as a technical point different from Patent Document 3, it is described as a main invention that a plurality of dyes are selected so as not to overlap the absorption spectrum on the long wavelength side and the emission spectrum on the short wavelength side relatively. Has been. In this document, too, the relationship between a plurality of fluorescent color materials has not been sufficiently analyzed, so that the target fluorescence intensity cannot be reliably ensured. On the other hand, Japanese Patent Application Laid-Open No. 2003-113331 (Patent Document 6) discloses an invention in which the fluorescence characteristics are improved by the relationship between the solvent and the fluorescent color material. Patent Document 6 has two types of fluorescent color materials of the same color (there is an example in which a color material having no fluorescence is added), and two types of organic solvents that are not compatible with each other (glycerin, nonionic surfactant, etc.) And a recording ink comprising pure water for dissolving them.
US Pat. No. 6,176,908 WO02 / 092707 specification JP-A-8-239610 Japanese Examined Patent Publication No. 60-45669 Japanese Patent Laid-Open No. 11-80632 JP 2003-113331 A

  As described above, there has not yet been proposed a water-based ink that improves the water resistance and density of a recorded image, in particular, the color developability including fluorescence, and has good reliability. The subject of the present invention is one of the biggest factors that hinders fluorescence emission, which has not been elucidated in the past, that is, “absorption characteristics of the used color material (for the color material to have color) This is to solve the “problem that has reduced the fluorescence emission property due to the light absorption characteristics”.

  Therefore, the object of the present invention is to elucidate this problem by focusing on the fixing state of the ink formed on the recording material based on new ideas and ideas, and to reduce the influence of the absorption characteristics of the color material used. To propose ink. The present invention also provides a recorded image having a good fluorescence emission on a recording material and a recorded image forming method using this ink.

  The above object can be achieved by the present invention according to the following embodiments.

  That is, the present invention forms the first concentrated image of the first water-dispersed color material including the second water-soluble color material at the center, and the entire periphery including the surface in the recording material of the first concentrated image. A water-based single fluorescent ink capable of forming a second concentrated image of the second water-soluble colorant, wherein the water-based single fluorescent ink comprises a first water-dispersed colorant, a second water-soluble colorant, An ethylene oxide adduct of a higher alcohol that contains a liquid medium that dissolves or disperses and water, and that can dissolve a large amount of the second water-dissolving colorant relative to the amount capable of dispersing the first water-dispersible colorant. A water-based single fluorescent ink comprising a surfactant that is liquid in a 25 ° C. environment, and wherein at least one of the first water-dispersed color material and the second water-soluble color material is a fluorescent color material It is.

  Further, the present invention forms a first concentrated image of the first water-dispersed color material including the second water-soluble color material at the center portion, and the entire periphery including the surface in the recording material of the first concentrated image. Forming a second concentrated image of a second water-dissolved color material containing a surfactant which is a liquid in an environment of 25 ° C. with an ethylene oxide adduct of a higher alcohol, a first water-dispersed color material, and a second water The recorded image is characterized in that at least one of the dissolved color materials is a fluorescent color material.

  Further, the present invention is a water-based single fluorescent ink capable of forming a fixing unit in which a plurality of micro-aggregated first water-dispersed color materials are scattered in the fixing unit of the second water-soluble coloring material, The aqueous simple substance fluorescent ink contains a first water-dispersed color material, a second water-soluble color material, a liquid medium that dissolves or disperses them, and water, and an amount capable of dispersing the first water-dispersed color material. A higher alcohol ethylene oxide adduct capable of dissolving a relatively large amount of the second water-soluble coloring material, and containing a surfactant that is liquid in an environment at 25 ° C., and at least one of the coloring materials is fluorescent. It is a water-based simple substance fluorescent ink characterized by being a material.

  In addition, the present invention has a fixing portion in which a plurality of finely agglomerated first water-dispersed coloring materials are interspersed in the fixing portion of the second water-soluble coloring material, and is an ethylene oxide adduct of a higher alcohol. A second concentrated image portion of a second water-soluble color material containing a surfactant that is liquid in an environment of 25 ° C. is formed, and at least one of the first water-dispersed color material and the second water-soluble color material One of the recorded images is a fluorescent color material.

  Further, the present invention forms a first concentrated image of a first water-dispersed color material including a second water-soluble color material at the center on a recording material, and the first concentrated image is recorded in the recording material. A second concentrated image of the second water-soluble colorant containing the surfactant which is a liquid in an environment of 25 ° C. with an ethylene oxide adduct of higher alcohol is formed on the entire periphery including the surface of the first water-dispersed color A recording image forming method for forming an image with a plurality of dots by applying a water-based simple ink in which at least one of the material and the second water-dissolving color material is a fluorescent color material, wherein a second water-dissolving color is formed between the plurality of dots A recorded image forming method comprising applying a water-based simple fluorescent ink so that a first concentrated image forming portion of a first water-dispersed color material containing a material is not adjacent.

  Further, the present invention forms a first concentrated image of the first water-dispersed color material containing the second water-soluble color material at the center on the recording material, and 25 ° C. with an ethylene oxide adduct of higher alcohol. A second concentrated image portion of the second water-soluble coloring material containing a surfactant that is a liquid under the environment is formed, and the second concentrated image portion of the first concentrated image including the surface inside the recording material is further formed on the entire periphery. A recording image forming method for forming an image by applying an aqueous single-color fluorescent ink capable of forming a second concentrated image of a water-soluble color material, and forming a recorded image so that the vertical resolution differs from the horizontal resolution This is a recorded image forming method.

  According to the present invention, a fixing portion in which a plurality of finely agglomerated first water-dispersed color materials are disposed in the fixing portion of the second water-soluble color material is formed on the recording material. A recording image forming method for forming an image with a plurality of dots by applying an aqueous simple substance fluorescent ink in which at least one of the water-dispersed color material and the second water-soluble color material is a fluorescent color material, comprising ethylene oxide of a higher alcohol A second concentrated image portion of a second water-dissolving color material containing a surfactant which is a liquid in an environment of 25 ° C. is formed as an adduct, and further from a plurality of finely agglomerated water-dispersed color materials between a plurality of dots. This is a recorded image forming method in which a water-based simple fluorescent ink is applied so that the fixing portion by the first water-dispersed color material is not adjacent, and a recorded image is formed so that the vertical resolution is different from the horizontal resolution.

  The present invention also provides a water-dispersible colorant having a carboxylic acid as a main water-soluble group in a free acid state, a water-soluble colorant mainly having a sulfonic acid as a water-soluble group in a free acid state, Dissolvable water-soluble colorant containing sulfonic acid as the main water-soluble group in the free acid state relative to the water-dispersible dispersible amount mainly containing the carboxylic acid as the water-soluble group in the acid state A water-based simple fluorescent ink characterized by containing an ethylene oxide adduct of a higher alcohol that can be contained in a large amount and a surfactant that is liquid in an environment at 25 ° C. and water.

In addition, these water-based simple fluorescent inks preferably contain a water-soluble crystalline substance that is solid in a normal temperature environment, and the surfactant is an ethylene oxide addition of a higher alcohol having 12 or more carbon atoms. It is preferable that it is a liquid in a 25 ° C. environment. The water-dispersible colorant is preferably a self-dispersing pigment in which a hydrophilic group is bonded directly or via another atomic group, and optimally the surface functional group density is 0.6 μmol / m ^2. It is preferably 2.5 μmol / m ² or less. These can be used alone or in combination, and are one of the elements that can improve the fluorescence intensity.

  As described above, according to the present invention, the presence of a surfactant which is an ethylene oxide adduct of a higher alcohol and is a liquid in an environment at 25 ° C. has ensured remarkably excellent fluorescence coloring property. In addition, according to the present invention, it is possible to provide a single aqueous fluorescent ink, a fluorescent recording image, and a recording method that improve both the image fastness, the color developability of the recorded image, and the excellent fluorescent color developability. In addition, reliability such as sticking resistance and dischargeability was also good.

  Further, according to each of the present invention, the visual color of the obtained recorded image can be visually recognized in a plurality of colors, and in particular, the overlap of the emission wavelength and the absorption wavelength, which has been conventionally known in the case of fluorescent color development. Thus, it was possible to improve the problem of lowering the fluorescence intensity due to the above, and to obtain a good fluorescence image.

  Furthermore, when the ink of the present invention was used in the ink jet recording method, good reliability could be obtained. In particular, in an ink using a self-dispersing color material as a water-dispersed color material, ink adheres to the periphery of the nozzle by continuous ejection, and ink droplets adhere to the blade surface that removes ink adhering to the nozzle surface. It was possible to reduce and to obtain a favorable effect.

  Next, the present invention will be described in more detail with reference to preferred embodiments of the invention.

  First, a mechanism for improving the image fastness, particularly water resistance, and improving the color quality including fluorescence of the recorded image and the image quality including the image density by the aqueous simple ink of the present invention will be described. In addition, the mechanism described below was reached by considering various phenomena based on experimental data and repeating trial and error. However, the present invention includes a complex interaction, and thus covers all of them. Not what you want.

  The inventors of the present invention have good reliability, safety, etc., improve image fastness including water resistance, particularly water resistance, and also improve color developability and image density including fluorescence of recorded images. The ink has been examined and confirmed. As a result, a first concentrated image of the first water-dispersed color material containing the second water-dissolving color material is formed at the center, and the second water is applied to the entire periphery including the surface in the recording material of the concentrated image. The water-based simple ink capable of forming the second concentrated image of the dissolved coloring material has reached the fact that the fastness of the recorded image, in particular, the water resistance and quality, the color development including fluorescence, and the image density are improved. It came to.

  First, conventional ink will be described. FIG. 5 shows one model. In FIG. 5, a portion indicated by ◯ (black coating) is a fixing portion of the color material, and indicates dots formed by ink droplets. The upper surface in FIG. 5 is a plan model view of a dot as a fixing portion of a color material formed from one ink droplet applied to a recording material as viewed from above the recording surface of the recording material. The cross-sectional view of FIG. 5 is a model diagram of the inside of the recording material of dots composed of a fixing portion of a color material formed from ink droplets applied to the recording material. Here, FIG. 21 is a diagram obtained by observing the concentrated image formed on the recording material of FIG. 5 at a magnification of 330 times. The black portion is a water-dispersed color material, and the blurred portion is a liquid medium. Further, FIG. 22 is a diagram in which the concentrated image formed on the recording material with the ink of FIG. 5 is observed at a magnification of 132 times. The black portion is the water-dispersed color material, and the blurred portion is the liquid medium.

  In order to increase the recording image density, there are methods of increasing the color material content of ○ (black coating) in the ink or making it difficult for the ink to penetrate into the recording material. At this time, if the color material of ○ (black coating) is a colorant with good water resistance, the solubility of the coloring material of ○ (black coating) in water is due to aggregation and association of the coloring material of ○ (black coating). The water resistance is improved. However, in these states, the color material is fixed on the recording material in an associated, aggregated or aggregated state. However, the association, aggregation, or aggregation state deteriorates the color developability inherent to the color material, so that the color developability of the ink on the recording material is lowered.

  On the other hand, as shown in FIG. 6, when using a plurality of color materials to improve water resistance or a color material capable of increasing the density, or a color material having good color developability, a plurality of color materials are mixed. For example, when a color material that improves water resistance is used, the color material is in a mixed state with respect to color development even though the water resistance can be improved. It will settle. That is, since the aggregation, association, and aggregation state of the color materials are likely to occur, it is difficult to improve the color developability. In addition, if the ink permeability to the recording material is reduced for the purpose of increasing the image density, a plurality of color materials are fixed on the recording material in the same mixed state as described above. Sexuality will decline. In particular, when a fluorescent color material is used for the purpose of fluorescent emission, the color emission is greatly reduced because the color material is mixed, that is, the color material is aggregated, associated, or aggregated. End up.

  In FIG. 6, the first color material is represented by a black diamond shape, and the second color material is represented by a white diamond. The upper surface in FIG. 2 is a plan model view of a dot as a fixing portion of a color material formed from one ink droplet applied to a recording material as viewed from above the recording surface of the recording material. The cross-sectional view of FIG. 2 is a model diagram of the inside of the recording material of dots composed of a fixing portion of a color material formed from ink droplets applied to the recording material.

  On the other hand, FIG. 7 shows a model diagram of the dot formation state of the aqueous simple ink of the present invention. In FIG. 7, the black paint portion is a portion where at least the first color material is fixed, and the white portion is a portion where only the second color material is fixed. The upper surface in FIG. 7 is a plan model view of a dot as a fixing portion of a color material formed from one ink droplet applied to a recording material as viewed from above the recording surface of the recording material. The cross-sectional view of FIG. 7 is a model diagram of the inside of the recording material of dots composed of a color material fixing portion formed from one ink droplet applied to the recording material.

  In a preferred embodiment of the water-based simple ink according to the present invention, before being applied to the recording material, an aqueous liquid medium (usually composed of water and a water-soluble organic solvent), the first water-dispersed color material, and the second water. Although it contains dissolved color material, when this aqueous simple ink is applied to the recording material, the ink droplets are caused by evaporation of the liquid medium on the recording material, penetration into the recording material, and diffusion. Becomes established.

  In the process of fixing the color material of the ink to the recording material and forming an image, in the aqueous simplex ink of the present invention, the first water-dispersed color material is in a state where ink droplets are applied to the recording material. Alternatively, the second water-dissolved color material is diffused on and in the recording material, whereas a concentrated image is formed only by slightly diffusing from a slightly applied position. , Forming a concentrated image. That is, the water-based simple ink of the present invention has a difference in the diffusibility of the first water-dispersed color material and the second water-soluble color material on the recording material and inside thereof, and the recorded image shown in FIG. Is formed. By this image formation, agglomeration, association, and aggregated state of the first water-dispersed color material are formed, and fastness such as water resistance and light resistance is improved. In addition, when the first water-dispersed color material forms a collective image on the recording material, the color material is fixed in a concentrated manner, so that an image density with high impact and a high density recording image can be obtained. .

  In contrast, the second water-dissolving color material apparently forms a concentrated image so as to surround the first water-dispersed color material. This is because, on the recording material, the cohesiveness, associating property, or aggregation property of the second water-soluble colorant is weaker than that of the first water-dispersible colorant, Therefore, the toner is fixed to the recording material in a state close to a monomolecular state, and therefore, it is expected that the color developing property can be improved. Also, the larger the spread of the second water-soluble color material in the recording material, the better the desired image characteristics.

  Furthermore, in FIG. 7, it is preferable that the first water-dispersed color material of the water-based simple ink is a water-dispersed color material, and the second water-soluble color material is a water-soluble color material. When the first water-dispersed color material is a water-dispersed color material, the aggregation characteristics can be easily improved, the image density can be increased, and the density of the entire recorded image can be increased. In addition, the water resistance can be improved.

  When a water-soluble color material is used as the second water-soluble color material, the water-soluble color material is diffused together with water as a main component on and inside the recording material. This state is expected to be easy to improve the color developability because it is likely to be fixed on the recording material in a state close to a monomolecular state.

  Further, the fixed image (for example, dots) of the ink droplets applied on the recording material forms a concentrated image of the aggregated color material mainly in the center, and further includes the periphery of the concentrated image including the surface in the recording material. Since the diffused color material is fixed throughout, the density is apparently lowered from the center to the periphery.For example, when forming an image with dots, the dots are less noticeable and the graininess of the obtained image is reduced. And good image formation is made easier.

  Further, in the case where the water-based simple ink is a fluorescent ink, the concentrated image portion by the second water-dissolving color material mainly than the concentrated image portion by the first water-dispersed color material including the second water-soluble color material. It has been found that the fluorescence emission becomes particularly good when the fluorescence emission is increased. In particular, it has been found that when a water-dispersed color material is used for the first water-dispersed color material and a water-soluble fluorescent color material is used for the second water-soluble color material, the image density is high and the fluorescence emission is improved. When a fluorescent color material is used for the second water-soluble color material, it diffuses on the recording material, so that the fluorescent color material hardly aggregates and aggregates on the recording material, and a good fluorescent emission is obtained. Can do. In addition, since the first water-dispersed color material can improve the density for the reason described above, it is possible to obtain a recorded matter with a high overall density of the recorded image and good fluorescence. It becomes possible. Furthermore, the water resistance can be improved due to the cohesiveness of the first water-dispersed coloring material.

  For the above reasons, when an image is formed with a plurality of dots so as not to adjoin the first concentrated image forming portion of the first water-dispersed color material including the second water-soluble color material using the aqueous simple ink ( As shown in FIG. 10, it is easy to obtain the second concentrated image region using the second water-dissolved color material, and it has been found that a very good recorded image can be obtained. In FIG. 10, ◯ (black coating) indicates a concentrated image region by the first water-dispersed color material, and white portions indicate the concentrated image region by the second water-soluble color material. Further, the upper surface in FIG. 10 is a plan model view of two dots as a fixing portion of a color material formed from two ink droplets applied to a recording material viewed from above the recording surface of the recording material. The cross-sectional view of FIG. 10 is a model diagram of the inside of the recording material of dots composed of the fixing portion of the color material formed from the ink droplets applied to the recording material. a shows the distance between the concentrated image areas of the first water-dispersed color material.

  Further, a concentrated image of the first water-dispersed color material including the second water-soluble color material at the center is formed on the recording material with the water-based simple ink, and includes the surface of the concentrated image in the recording material. When the recorded image is formed so that the resolution of the recorded image formed using the water-based simple ink that forms the concentrated image of the second water-dissolved color material on the entire periphery is the vertical resolution ≠ the horizontal resolution, It was found that the diffusion region of the water-soluble coloring material can be secured, and the effect of the aqueous simple ink of the present invention can be further improved.

  For example, as shown in FIG. 11, a plurality of ink droplet dots are provided on the recording material so as not to adjoin the concentrated image forming portion of the first water-dispersed color material including the second water-soluble color material. In addition, there is an unapplied dot portion that does not apply ink droplets between the ink dots. FIG. 11 is a model diagram in which the recording surface of the recording material is a plan view, where ◯ (black coating) is a portion to which ink droplets have been applied, and ◯ is a portion to which ink droplets have not been applied.

  In the recording method as shown in FIG. 11, a concentrated image of the first water-dispersed color material including the second water-dissolved color material is formed at the center of the circle (blacked), and the concentrated image in the recording material When the water-based simple ink is used to form a concentrated image of the second water-dissolving color material on the entire periphery including the surface, the recorded image becomes as shown in FIG. This makes it easy to form a concentrated image, and the effects of the present invention can be expressed well. In FIG. 12, ◯ (black coating) is a concentrated image area where the first water-dispersed color material is fixed, and the surrounding area is a concentrated image area where the second water-soluble color material is fixed. .

  Further, in the recording image formation, in order to obtain the image formation as shown in FIG. 12, the image formation that becomes dot-on-dot is not preferable. When dot-on-dot is selected, the concentrated image forming area of the second water-dissolving color material includes the first concentration image of the first water-dispersed color material including the second water-dissolving color material and the second water-dissolving color material. Concentrated images are mixed, which is not preferable.

  The inventors of the present invention are a water-dispersed colorant, a water-soluble colorant, and an ethylene oxide adduct of a higher alcohol that can contain a relatively large amount of water-soluble colorant relative to the water-dispersed colorant. It has been clarified that the effect of the present invention can be satisfactorily achieved by using a single aqueous ink containing a surfactant which is liquid below and water. In this way, a model is shown in the case of using a surfactant that is liquid in an environment of 25 ° C. with an ethylene oxide adduct of a higher alcohol that can contain more water-soluble colorant than water-dispersed colorant. 8 and 9.

  In FIGS. 8 and 9, the black portion indicates the first water-dispersed color material fixing portion, and the white portion indicates the second water-soluble color material fixing portion. 8 and 9 are plan model views of dots as a fixing portion of a color material formed from one ink droplet applied to a recording material when viewed from above the recording surface of the recording material. The cross-sectional views of FIGS. 8 and 9 are model diagrams of dots inside the recording material, which are composed of fixing portions of color materials formed from ink droplets applied to the recording material.

  When a surfactant, which is a higher alcohol ethylene oxide adduct that can contain a large amount of water-soluble colorant relative to the water-dispersed colorant and is liquid in an environment at 25 ° C., is used in the ink, The tension decreases, the wettability with respect to the recording material increases, and it easily penetrates and diffuses inside. At this time, the surfactant, which is an ethylene oxide adduct of higher alcohol and is liquid in an environment of 25 ° C., is oriented to the recording material around the vicinity including the surface of the application area where the ink droplets of the recording material are applied, It diffuses while adsorbing. At this time, a relatively large amount of water-dissolving color material can be contained in the water-dispersed color material, that is, the second water-dissolving color material is relatively dissimilar to the amount capable of dispersing the first water-dispersed color material. If a surfactant that is a liquid in a 25 ° C environment is used as an ethylene oxide adduct of a higher alcohol that can dissolve a large amount of the color material, the water-soluble color material diffuses along with the main component water in the recording material. Then, the fixing area of the second water-soluble coloring material is to be secured in a wide range. That is, the water-soluble coloring material diffuses and permeates on and in the recording material together with the ink solvent, the higher alcohol ethylene oxide adduct, and the surfactant which is liquid in an environment of 25 ° C. In this state, the color material is separated on and inside the recording material, and the ink is fixed as shown in FIGS. FIG. 19 is a diagram in which the micro-aggregated color material formed on the recording material with the ink of the present invention of FIGS. 8 and 9 is observed at a magnification of 330 times. The part is a liquid medium. FIG. 20 is a diagram observing a micro-aggregated color material formed on the recording material with the ink of the present invention of FIGS. 8 and 9 at 132 times. The black portion is a water-dispersed color material, and the blurred portion is a liquid. It is a medium.

  On the other hand, a surfactant which is an ethylene oxide adduct of a higher alcohol and is liquid in an environment at 25 ° C. is present in the recording material by adsorption or the like, mainly in the vicinity where ink droplets are applied to the recording material. The dispersion color material is less likely to diffuse relative to the water-soluble color material, and the aggregation tendency is further accelerated in combination with the aggregation characteristics of the water dispersion color material. At this time, since the water-dispersed color material does not aggregate locally but aggregates while diffusing, in the concentrated image region of the water-dispersed color material, aggregation with dispersibility, that is, the concentrated region of the water-dispersed color material Is formed as an aggregate in which the aggregation of the water-dispersed color material is scattered. That is, in FIGS. 8 and 9, when the first water-dispersed color material forms a concentrated image on the recording material, the aggregate of the first water-dispersed color material is within the aggregated image portion in the concentrated image portion. And a set of the aggregates forms a concentrated image.

  Further, in the first concentrated image region of the first water-dispersed color material, the first water-dispersed color can be obtained by using a higher alcohol ethylene oxide adduct and a surfactant that is liquid in an environment at 25 ° C. Since the amount per unit area of the material decreases and the area occupied by the second water-dissolved color material increases, the apparent image density hardly changes and the color developability is improved. In particular, when the second water-soluble coloring material is made fluorescent, the fluorescence emission is good (see FIGS. 8 and 9). In this state, the first concentrated image portion of the first water-dispersed color material including the second water-soluble color material is the first water-dispersed color material fixing portion and the second water-soluble color material fixing portion. Since the first water-dispersed color material and the second water-dissolved color material are separated to form a mixed concentrated image, the first water-dispersed color material improves the recording density, When a color material that improves color developability, particularly a fluorescent color material, is used for the second water-soluble color material, the color developability including the density and fluorescence of the recorded image is improved. Further, the water resistance can be improved due to the aggregation characteristics of the first water-dispersed color material.

  Further, the first water-dispersed color material forms a plurality of small aggregates as shown in FIGS. 8 and 9, but for the visual identification, the aggregation state is small beyond the human eye identification limit. Aggregation is perceived by the human eye as one aggregate, and the recorded image density is comparable to that which does not form a plurality of small aggregates. Furthermore, when forming a recorded image with dots, the dots are less noticeable, and a recorded image with good quality can be obtained. In addition, when the content of the surfactant, which is an ethylene oxide adduct of higher alcohol and is liquid in an environment at 25 ° C., is higher than the critical micelle concentration, the ink diffuses well on the recording material and inside it. Thus, the effect of the present invention is improved.

  Further, it is preferable that the difference between the dynamic interfacial tension and the static interfacial tension of the surfactant which is an ethylene oxide adduct of higher alcohol used and is liquid in a 25 ° C. environment is smaller. That is, it means that the higher the orientation speed to the interface of the surfactant which is an ethylene oxide adduct of higher alcohol and is liquid in an environment of 25 ° C., and accelerates the diffusion of the ink liquid medium on and inside the recording material. Furthermore, when a water-dispersed color material is used in the present invention, the surfactant which is a liquid in an ethylene oxide adduct of the higher alcohol in a 25 ° C. environment is quickly applied to the water-dispersed color material. It is easy to perform the adsorption action, and therefore is oriented and adsorbed to a small aggregated water-dispersed color material, so that a micro-aggregated water-dispersed color material can be formed on the recording material, further improving the effects of the present invention. To do.

  As a method of distinguishing the combination of the surfactant and the water-dispersed colorant, which is a preferable higher alcohol ethylene oxide adduct in a 25 ° C. environment, for example, a desired water-dispersed colorant solution, for example, 15% by mass The water-dispersed colorant was selected by dropping the water-dispersed solution with a selected higher alcohol ethylene oxide adduct with a dropper (for example, about 0.1 g) onto a surfactant liquid that is liquid in an environment of 25 ° C. It is an ethylene oxide adduct of a higher alcohol that has a cohesive property at the surfactant liquid interface that is liquid in an environment of 25 ° C. and forms a floating state. The water-dispersed coloring material does not dissolve and settles when left in an environment of ° C.

  The image is shown in FIGS. Each figure schematically shows the state immediately after dropping (left figure) and after aging (right figure) when a container such as a petri dish is filled with the following surfactant solution and the water-dispersed coloring material is dropped. is there.

  Particularly preferred is FIG. 1, and immediately after dropping, the water-dispersed colorant is a higher alcohol ethylene oxide adduct and is separated in a floating state on the surface of the surfactant which is liquid in a 25 ° C. environment. It shows that it separates in the precipitated state at the bottom. Next, FIG. 2 is preferable. Immediately after the dropping, the water-dispersed coloring material is an ethylene oxide adduct of a higher alcohol and is separated in a precipitated state at the bottom of a surfactant solution that is liquid in an environment of 25 ° C. Also shows separation in the precipitated state at the bottom.

  On the other hand, FIG. 3 and FIG. 4 show an unfavorable combination. In FIG. 3, it is separated in a precipitated state at the bottom of the surfactant solution other than the present invention, but after the lapse of time, it diffuses throughout and dissolves. It has become. In FIG. 4, the water-dispersed coloring material is separated in a floating state on the surface of the surfactant other than the present invention immediately after the dropping, but after the passage of time, it is diffused and dissolved.

  In the present invention, in consideration of various characteristics of the ink and coloring material used, the surfactant that is liquid in an ethylene oxide adduct of the higher alcohol used in a 25 ° C. environment is a nonionic higher alcohol. When a surfactant which is an ethylene oxide adduct and is liquid in a 25 ° C. environment is selected, there are few harmful effects.

  If it has polarity, it may be easy to form a salt with a large number of anions and cationic components contained in the ink, and therefore it may be difficult to form a favorable state of orientation to the interface. This is because it may be difficult to make aggregation of the water-dispersed coloring material good.

  On the other hand, the water-based simple ink of the present invention includes a water-soluble crystalline substance (solid in a normal temperature environment) in addition to the above-described surfactant that is an ethylene oxide adduct of a higher alcohol and is liquid in a 25 ° C. environment. It preferably contains a crystal forming component). The ink of this preferred embodiment is a water-dispersed coloring material, a water-soluble coloring material, a liquid medium (aqueous medium), a higher alcohol ethylene oxide adduct having the above-described action, and a surfactant and water that are liquid in a 25 ° C. environment. Soluble crystal forming components are mixed and in a stable state. If such ink is left unattended, the water content in the ink decreases due to evaporation, and the concentration of the water-soluble crystal-forming component in the ink reaches the saturation concentration in the ink, causing the crystal-forming component to crystallize. Start. At the same time, the water-dispersed color material also reaches a saturated concentration, and the color material dispersion state becomes unstable and easily aggregates.

  When these two states, that is, a state in which crystals are precipitated in the ink and a state in which the water-dispersed color material is unstable and easily aggregated, are expressed simultaneously, the individual crystals in which the water-dispersed color material is precipitated in the ink As a nucleus, an aggregate dispersion of water-dispersed color materials aggregated around the crystal is formed (FIG. 13). The ink in this state is a state in which an aggregate of dispersed color materials having crystals as nuclei exists in the ink, and a network of water dispersed color materials is formed in an ink state using a normal water dispersed color material (see FIG. 14) is inhibited.

  In addition to this, when the concentration of the surfactant, which is an ethylene oxide adduct of a higher alcohol having the above-mentioned action and is liquid in a 25 ° C. environment, increases the cohesiveness of the water-dispersed colorant, the water-dispersed color An aggregate dispersion of materials is likely to be formed. Since an aggregate of dispersed color materials having crystals as nuclei is difficult to form this network, it does not form strong adhesion as in the case of the dispersed color material alone, and therefore has good adhesion resistance and clogging resistance.

  Furthermore, since this aggregate has a water-soluble nucleus, for example, even if clogging occurs near the nozzle of the inkjet head, if recovery operation such as suction and pressurization is performed, clogging occurs near the nozzle The clogged state can be easily recovered by the action from outside and inside the aggregate of the water-dispersed coloring material having the crystal as a nucleus.

  Further, on the recording material, the water applied to the recording material is reduced in water due to evaporation and permeation, and the water-dispersed color material aggregate in which the crystal components gather around the core is the surface phase portion of the recording material. At the same time, since the water-dispersed colorant chemically and physically interacts strongly with the cellulose fibers constituting the recording material, fastness such as water resistance is improved (FIG. 15).

  Further, since the water-dispersed color material and the water-soluble color material coexist in the ink, the color development property and the sticking resistance of the recorded image are further improved. This is probably because, in the ink in which the conventional water-dispersed color material and the water-soluble color material coexist, the water content of the ink applied to the recording material is reduced and is fixed to the recording material. The water-dissolving colorant is also taken into the aggregation network of the water-dispersed colorant, and the water-dissolving colorant is also in an agglomerated state together with the water-dispersed colorant. It is expected that expression will be difficult (FIG. 16).

  However, in the present invention, the water-dispersed colorant does not aggregate locally by the action of the surfactant, which is an ethylene oxide adduct of higher alcohol described above and is liquid in an environment of 25 ° C., and aggregates while diffusing. Furthermore, due to the above-described action when the crystal is formed from the crystal forming component, the state where the water-dispersed color material is agglomerated and the aggregate of the dispersed color material centered on the crystal are scattered. A state is formed, and as a result, the formation of large local aggregates of the water-dispersed colorant is inhibited. For this reason, there is no network of water-dispersed color material, and the water-soluble color material is present in the non-aggregate portion of the solvent portion in the ink, so that the water-soluble color material is expected to develop a good color ( FIG. 17).

  Further, the reason for improving the sticking resistance is that the aggregate can be made to exist satisfactorily due to the buffer effect between the aggregates in which the water-dispersed coloring material gathers around the crystal as a nucleus, and the solvent in the ink. In the presence of a water-soluble colorant having a higher solubility than the water-dispersed colorant, the water-dispersed colorant is favorably crystallized due to the difference in solubility of the two colorants in the ink. It is expected that they will gather in the aggregate (Fig. 18).

  When a fluorescent colorant is used as the water-soluble colorant, it is particularly effective in increasing the fluorescence intensity of the image. This is expected to express high fluorescence intensity because the fluorescent color material is in a monomolecular state and is not taken into the aggregation of the water-dispersed color material like the previous water-soluble color material. Further, in this case, the fluorescent color material is less than the content that exhibits density quenching on the recording material, for example, the content of the fluorescent color material that exhibits density quenching in a state where water is removed from the aqueous ink composition. A lower content is required. Here, concentration quenching refers to a phenomenon in which the fluorescence intensity decreases as the content of the fluorescent color material in the ink increases.

  Furthermore, the ink of the present invention contains at least an aqueous medium, a water-dispersed coloring material, and a crystal forming component as components of the ink, but it is preferable to use an organic solvent in which the crystal forming component is dissolved in the ink. A favorable effect can be obtained.

  According to the ink of the present invention in which such an organic solvent is used in combination, the water-dispersed coloring material not only easily forms an aggregate having crystals as nuclei, but also contains an organic solvent for anti-sticking property. This is because the aggregate can be independently contained in the ink, and the water-dispersed color material aggregate is effectively expressed. In particular, the organic solvent is preferably a solvent that does not easily volatilize in a normal temperature environment, such as glycerin and triethylene glycol. Further, if the organic solvent can also solubilize the water-soluble coloring material, the coloring property including the fluorescence of the recorded matter is further improved. That is, a good dissolved state of the water-soluble coloring material can be ensured by the organic solvent.

  Furthermore, the relationship between the organic solvent and the crystal forming component is such that the content of the crystal forming component contained in the ink is equal to or higher than the saturation concentration with respect to the content of the organic solvent used in the selected ink. It is particularly preferred. This is to make it easy to make an aggregate of water-dispersed color materials having crystals obtained from the crystal-forming components as nuclei. Therefore, the saturation concentration of the crystal forming component in the organic solvent is particularly preferably not more than the saturation concentration relative to the water used in order to develop the mechanism of the present invention.

  Further, when the content of the crystal-forming component in the ink is not more than the saturated concentration with respect to water in the ink and not less than the saturated concentration with respect to the organic solvent used in the ink, the effect of the present invention is further improved. It can be expressed. That is, in the ink, the crystal-forming component is dissolved well, and when the evaporation component in the ink is evaporated, the crystal formation of the crystal-forming component can be rapidly manifested.

  On the other hand, the present inventors have prepared a water-dispersible colorant having a carboxylic acid as a main water-soluble group in a free acid state, and a water-soluble colorant mainly having a sulfonic acid as a water-soluble group in a free acid state. A higher alcohol that can contain a large amount of a colorant mainly containing carboxylic acid as a water-soluble group in a free acid state and a sulfonic acid as a main water-soluble group in a free acid state. When a water-based simple ink containing a surfactant that is liquid in an environment of 25 ° C. and water is used, the density and fastness of a recorded image are improved, and a water-soluble colorant is used. It was elucidated that color development and quality could be improved.

In particular, the first water-dispersed colorant is a water-soluble colorant having carboxylic acid as a main water-soluble group in the state of a free acid, and the second water-soluble colorant is a main water-soluble substance in a state of a free acid. The water-soluble coloring material used as a base improves the density, fastness, and color developability of the recorded image. Further, when forming a recorded image with dots, the dots are not noticeable and a good quality recorded image is obtained. It becomes possible. Carboxylic acids are less hydrophilic than sulfonic acids and tend to aggregate. Furthermore, it contains a relatively large amount of the coloring material having sulfonic acid as the main water-soluble group in the free acid state relative to the coloring material having carboxylic acid as the main water-soluble group in the free acid state. When a surfactant that is a higher alcohol ethylene oxide adduct and is liquid in an environment of 25 ° C. is used, the colorant containing carboxylic acid as a main water-soluble group in a free acid state has a high density and fastness of recorded images. The colorability and quality can be improved by using a colorant having sulfonic acid as a main water-soluble group in a free acid state. Furthermore, these effects can be further improved by including the above-mentioned crystal forming components. In addition, these water-based simple fluorescent inks preferably contain a water-soluble crystalline substance that is solid in a normal temperature environment, and the surfactant is an ethylene oxide addition of a higher alcohol having 12 or more carbon atoms. It is preferable that it is a liquid in a 25 ° C. environment. The water-dispersible colorant is preferably a self-dispersing pigment in which a hydrophilic group is bonded directly or via another atomic group, and optimally the surface functional group density is 0.6 μmol / m ^2. It is preferably 2.5 μmol / m ² or less. These can be used alone or in combination, and are one of the elements that can improve the fluorescence intensity.

  Hereinafter, the components of the ink of the present invention that can provide excellent effects by the above-described mechanism will be described.

  It is important that the first and second water-soluble coloring materials, which are constituents of the present invention, are a combination capable of separating them on the recording material. As a method for separating them on the recording material, a method using a difference in solubility of the coloring material with respect to the pH of the surface of the recording material, and a component that lowers the solubility in one coloring material in the ink are included. , A method of applying ink to a recording material and reducing the solubility by acting on one of the color materials when the water component is reduced, and a component that improves the solubility with respect to one of the volatile color materials. A method of evaporating the volatile component and reducing the solubility of the coloring material when the ink is applied to the recording material is used. At this time, the solubility / dispersibility of the first water-dispersed color material is preferably lower than that of the second water-dissolved color material.

  As the color material used in the ink, it is preferable to use a water-dispersed color material and a water-soluble color material.

  The water-dispersed coloring material is hardly dispersed or dissolved in water by itself, and is a water-solubilizing group such as a surfactant or a polymer that is a liquid in an environment of 25 ° C and is an ethylene oxide adduct of a higher alcohol. It is a compound that has a low molecular weight hydrophilic group and the surface of a colorant that is dispersed in water by chemical and physical action, or by oxidizing the surface of a compound having a low molecular weight hydrophilic group or colorant. It refers to a color material in which hydrophilic groups such as sulfonic acid and carboxylic acid are chemically bonded.

  For example, the water-dispersed colorant is a carbon black pigment such as furnace black, lamp black, acetylene black, channel black or the like as an inorganic pigment, and specifically, Raven 7000, Rayvan 5750, Rayvan 5250, Rayvan 5000 ULTRA. -, Ray-Van 3500, Ray-Van 2000, Ray-Van 1500, Ray-Van 1250, Ray-Van 1200, Ray-Van 1190 ULTRA-II, Ray-Van 1170, Ray-Van 1255 (manufactured by Columbia), Black Pearls L, Legal 400R, Legal 330R , Regal 660R, Mogul L, Monarch 700, Monak 800, Monak 880, Mo 900, Monak 1000, Monak 1100, Monak 1300, Monak 1400, Vulcan XC-72R (above Cabot), Color Black FW1, Color Black FW2, Color Black FW2V, Color Black FW18, Color Black FW200, Color Black S150, Color Black S160, Color Black S170, Printex 35, Printex U, Printex V, Printex 140U, Printex 140V, Special Black 6, Special Black 5, Special Black 4A, Special Black 4 (manufactured by Degussa), No. 25, no. 33, no. 40, no. 47, no. 52, no. 900, no. Commercially available products such as 2300, MCF-88, MA600, MA7, MA8, MA100 (manufactured by Mitsubishi Chemical Co., Ltd.) and other newly prepared products can also be used. These can be used alone or in combination of two or more.

  Specific examples of organic pigments include insoluble azo pigments such as toluidine red, toluidine maroon, Hansa Yellow, Benzidine Yellow, and pyrazolone red, soluble azo pigments such as Ritolol Red, Helio Bordeaux, Pigment Scarlet, and Permanent Red 2B, Alizarin, Indantron Derivatives from vat dyes such as thioindigo maroon, phthalocyanine pigments such as phthalocyanine blue and phthalocyanine green, quinacridone pigments such as quinacridone red and quinacridone magenta, perylene pigments such as perylene red and perylene scarlet, isoindolinone yellow , Isoindolinone pigments such as isoindolinone orange, benzimidazolone yellow, benzimidazolone orange, benzimidazolone red, etc. Dazolone pigments, pyranthrone pigments such as pyranthrone red, pyranthrone orange, thioindigo pigments, condensed azo pigments, thioindigo pigments, diketopyrrolopyrrole pigments, flavanthrone yellow, acylamide yellow, quinophthalone yellow, nickel azo Other pigments such as yellow, copper azomethine yellow, perinone orange, anthrone orange, dianthraquinonyl red, dioxazine violet can be exemplified. These can be used alone or in combination of two or more.

  Further, when the organic pigment is represented by a color index (CI) number, C.I. I. Pigment Yellow 12, 13, 14, 17, 20, 24, 55, 74, 83, 86, 93, 97, 98, 109, 110, 117, 120, 125, 128, 137, 138, 139, 147, 148, 150, 151, 153, 154, 155, 166, 168, 180, 185, C.I. I. Pigment orange 16, 36, 43, 51, 55, 59, 61, 71, C.I. I. Pigment Red 9, 48, 49, 52, 53, 57, 97, 122, 123, 149, 168, 175, 176, 177, 180, 192, 202, 209, 215, 216, 217, 220, 223, 224, 226, 227, 228, 238, 240, 254, 255, 272, C.I. I. Pigment violet 19, 23, 29, 30, 37, 40, 50, C.I. I. Pigment blue 15, 15: 1, 15: 3, 15: 4, 15: 6, 22, 60, 64, C.I. I. Pigment green 7, 36, C.I. I. Examples thereof include CI Pigment Brown 23, 25, 26, and the like. Furthermore, C.I. I. Pigment Yellow 13, 17, 55, 74, 93, 97, 98, 110, 128, 139, 147, 150, 151, 154, 155, 180, 185, C.I. I. Pigment red 122, 202, 209, C.I. I. Pigment Blue 15: 3, 15: 4, etc., as described in JP-A-46-52950, U.S. Pat. Nos. 5,200,344, 5,554,739, JP-A-8-3498, U.S. Pat. A method in which a hydrophilic group is bonded through a diazonium group to disperse in water as a self-dispersing pigment, a method in which the surface of a coloring material is oxidized with hypochlorous acid to react with the hydrophilic group, and the coloring material is dispersed in water. A method of encapsulating in a surfactant or polymer and dispersing in water in the form of an emulsion or capsule, JP-A 05-179183, JP-A 06-136411, JP-A 07-053841, JP-A 10-87768 Disclosed in Japanese Patent Laid-Open No. 11-043639, Japanese Patent Laid-Open No. 11-236502, and Japanese Patent Laid-Open No. 11-269418. A dispersing agent such as active agent and polymer is physically adsorbed on the surface of the water-dispersible coloring material and a method of dispersing in the water.

  Examples of the dispersant include random or block polymerized styrene acrylic acid copolymer, styrene maleic acid copolymer, and the like; nonionic surfactants and anions capable of imparting a water dispersion state using a micelle state or an emulsion state Surfactant; or styrene, styrene derivative, vinyl naphthalene, vinyl naphthalene derivative, aliphatic alcohol ester of α, β-ethylenically unsaturated carboxylic acid, acrylic acid, acrylic acid derivative, maleic acid, maleic acid derivative, itaconic acid From at least two monomers selected from itaconic acid derivatives, fumaric acid, fumaric acid derivatives, vinyl acetate, vinylpyrrolidone, acrylamide, and derivatives thereof (of which at least one is a hydrophilic monomer) Block copolymer or random copolymer Copolymer, or salts thereof. Among these, a block copolymer is a particularly preferable dispersant for carrying out the present invention. This is because the water-dispersed color material obtained from the block copolymer has little variation among individual water-dispersed color materials, and can easily provide a stable ink.

  The block copolymer has a structure represented by AB, BAB, ABC type or the like. Block copolymers having a hydrophobic block and a hydrophilic block and having a balanced block size that contributes to dispersion stability are particularly advantageous in the practice of this invention. Functional groups can be incorporated into the hydrophobic block (the block to which the pigment is attached), thereby further enhancing the specific interaction between the dispersant and the pigment to improve dispersion stability. Also, the weight average molecular weight of the polymer can be less than 30,000, preferably less than 20,000, more preferably in the range of 2,000 to 10,000.

  The production methods for these polymers are disclosed in JP-A Nos. 05-179183, 06-136411, 07-053841, 10-87768, and 11-043639. This is disclosed in Japanese Patent Laid-Open Nos. 11-236502 and 11-269418.

  Representative hydrophobic monomers that can be used in the block copolymer include, but are not limited to, the following monomers: benzyl acrylate, benzyl methacrylate, methyl methacrylate (MMA), ethyl methacrylate (EMA) , Propyl methacrylate, n-butyl methacrylate (BMA or NBMA), hexyl methacrylate, 2-ethylhexyl methacrylate (EHMA), octyl methacrylate, lauryl methacrylate (LMA), stearyl methacrylate, phenyl methacrylate, hydroxyl ethyl methacrylate (HEMA), hydroxypropyl methacrylate , 2-ethoxyethyl methacrylate, methacrylonitrile, 2-trimethylsiloxyethyl methacrylate, glycidyl Methacrylate (GMA), p-tolyl methacrylate, sorbyl methacrylate, methyl acrylate, ethyl acrylate, propyl acrylate, butyl acrylate, hexyl acrylate, 2-ethylhexyl acrylate, octyl acrylate, lauryl acrylate, stearyl acrylate, phenyl acrylate, 2-phenylethyl Methacrylate, hydroxyethyl acrylate, hydroxypropyl acrylate, acrylonitrile, 2-trimethylsiloxyethyl acrylate, glycidyl acrylate, p-tolyl acrylate and sorbyl acrylate. Preferred hydrophobic monomers are benzyl acrylate, benzyl methacrylate, 2-phenylethyl methacrylate, methyl methacrylate, butyl methacrylate, 2-ethylhexyl methacrylate, and homopolymers and copolymers prepared therefrom, such as copolymers of methyl methacrylate and butyl methacrylate. It is preferable to produce a block copolymer.

  Typical hydrophilic monomers that can be used in the block copolymer include, but are not limited to, the following monomers: methacrylic acid (MAA), acrylic acid, dimethylaminoethyl methacrylate (DMAEMA) ), Diethylaminoethyl methacrylate, tert-butylaminoethyl methacrylate, dimethylaminoethyl acrylate, diethylaminoethyl acrylate, dimethylaminopropyl methacrylamide, methacrylamide, acrylamide and dimethylacrylamide. It is preferable to produce a block copolymer using a homopolymer or copolymer of methacrylic acid, acrylic acid or dimethylaminoethyl methacrylate.

  The acid-containing polymer is made directly or from blocked monomers having blocking groups that are removed after polymerization. Examples of blocked monomers that yield acrylic acid or methacrylic acid after removal of the blocking group include trimethylsilyl methacrylate (TMS-MAA), trimethylsilyl acrylate, 1-butoxyethyl methacrylate, 1-ethoxyethyl methacrylate, 1-butoxyethyl acrylate 1-ethoxyethyl acrylate, 2-tetrahydropyranyl acrylate and 2-tetrahydropyranyl methacrylate.

  The content of the pigment as the dispersible color material in the ink is not limited to this range, but the first water-dispersed color material and the second water-soluble color material are separated on the recording material. Therefore, when the content of the color material is too large, the aggregation state of the water-dispersed color material is fixed on the recording material in a state that is not preferable for the present invention. Accordingly, the content of the water-dispersed color material in the ink varies depending on the recording material type, for example, the sizing agent type and the internal addition amount. However, assuming a recording material generally used, it is less than 10% by mass. The range is preferable, more preferably less than 4% by mass, and still more preferably less than 2.5% by mass. The lower limit of the content of these pigments can be set according to the desired image density.

  In addition, in the case of dispersing a dispersing agent such as resin dispersion or surfactant dispersion in a water-dispersed colorant by a method such as physical adsorption, one kind of resin dispersion tree or surfactant is required alone or necessary. 2 or more can be used in combination, and the preferred dispersant amount is 0.5 to 10% by mass, preferably 0.8 to 8% by mass, and more preferably 1 to 6% by mass with respect to the total amount of the ink. % Range. If the content of the dispersant is higher than this range, it may be difficult to maintain a desired ink viscosity.

  If the content of the water-dispersed color material in the ink is too large, there is a water-dispersed color material that cannot be aggregated when forming an aggregate in which the crystal is the nucleus and the water-dispersed color material is aggregated around the crystal. It may be present in the ink, reducing the effects of the present invention. In addition, the water-dispersed color material can be used alone or in combination of two or more.

The water-soluble coloring material has a water-soluble group such as a sulfonic acid group, a carboxylic acid group, a phosphoric acid group, a hydroxyl group, and an amino group in the state of a free acid in the coloring material structure. It refers to those that can exist stably in water without the action of two components. As the fluorescent compound or fluorescent color material used as a constituent of the ink of the present invention, various compounds and color materials that excite and emit light can be used. For example, those excited by ultraviolet light and emitting light in the ultraviolet light wavelength region, visible light wavelength region, and infrared light wavelength region, those excited by visible light and emitting light in the visible light wavelength region and infrared light wavelength region, red Examples include those which are excited by external light and emit light in the visible light wavelength region and the infrared light wavelength region. Further, those containing the following atomic groups and basic structures in the structure are particularly preferred. The water-dispersible colorant is preferably a self-dispersing pigment in which hydrophilic groups are bonded directly or via other atomic groups, and optimally the surface functional group density is 0.6 μmol / m ² or more 2 It is preferable that it is 5 μmol / m ² or less.

  Specifically, those having a xanthene structure such as Acid Red 52, Acid Red 92, Acid Red 289, and Acid Yellow 73, those having a pyranine derivative such as Solvent Green 7 and those having a coumarin derivative such as Acid Yellow 184, etc. In addition to oxazole derivatives, thiazole derivatives, imidazole derivatives, imidazolone derivatives, pyrazolone derivatives, benzidine derivatives, diaminostilbendisulophonic acid derivatives, and the like, dyes having the structures shown in the following table and water-soluble products thereof are exemplified. Further, the water-soluble fluorescent dye can exhibit the highest effect of the present invention.

  In addition, as a compound exhibiting fluorescence, for example, generally used fluorescent whitening agents can be used. In particular, the water-soluble fluorescent color material A described below is one of good fluorescent color materials.

[Water-soluble fluorescent colorant A]

  The content of the fluorescent dye in the ink is, for example, preferably 0.01 to 30% by mass, and more preferably 0.05 to 20% by mass with respect to the total mass of the ink. When the recorded matter (recorded image) is required to have fluorescence, when recording is performed by applying the ink of the present invention to a recording material, concentration quenching (content in the ink exceeds a certain value) And a content that does not exhibit the property that the fluorescence intensity decreases). When emphasizing the improvement of fluorescence, the content is particularly preferably 3% by mass or less. However, it is not limited to these depending on the characteristics of the recording material and the fluorescent color material.

  In addition, those having a plurality of basic structures of fluorescent light emission in the structure in the fluorescent color material, such as those having a color material structure such as a dimer or trimer using a linking group, It exhibits an excellent effect on fluorescence emission, particularly on concentration quenching resistance.

  In addition, when the present invention is used for the purpose of fluorescence characteristics, it is more preferable for the present invention to make additional conditions in consideration of the following points.

  Here, “a plurality of fluorescent dyes” applicable to the present invention will be described. The “plurality of fluorescent color materials” described below is obtained by changing the fluorescence intensity of the first fluorescent color material showing fluorescence in the fluorescence wavelength region (for example, 580 nm to 620 nm) of the reference emission with respect to the reference excitation wavelength, and other fluorescence. This is a technique for significantly improving a desired fluorescence intensity in relation to a color material (hereinafter referred to as a second color material).

  For example, the fluorescent dye AR52 listed in the section of the prior art exhibits sufficient red region fluorescence even in water-based ink that absorbs ultraviolet light, but the recorded image has weak fluorescence due to ultraviolet excitation. In pursuit of this phenomenon, the excitation wavelength for the AR 52 to emit red fluorescence is not only in the ultraviolet region but also in the visible light region and depends on the fixing state of the fluorescent dye in the recording material. Was determined to be a factor. Therefore, a technical analysis was carried out to give how many excitation wavelengths for emitting red light or to make the dye fixing state as a recorded image effective for fluorescence emission.

  As described above, when AR52 is used as the first color material, as a single characteristic, although ink with water evaporated to 0.01% by mass or less shows sufficient fluorescence intensity, it is necessary to form an image. In this case, the density of the recording material is not fixed on the surface fiber of the paper or the envelope and is wasted inside the paper, and the fluorescence intensity decreases conversely when the amount of the first and second color materials in the ink is increased. The problem of quenching is one of the items to be considered. On the other hand, one of the considerations is that the energy applied is limited to the reference excitation wavelength. Other analyzes can be understood from the following description.

  Therefore, this multiple fluorescent color material solves at least one of the following problems (preferably, a plurality of the following problems) in order to improve the fluorescence intensity from the prior art level.

  The first problem of the multiple fluorescent color materials is to obtain the fluorescence emission of the second color material and the reference emission wavelength (hereinafter referred to as a reference fluorescence wavelength of one wavelength or a wavelength width) generated by the provision of the reference excitation wavelength. By paying attention to the correlation with the excitation wavelength of the first color material, it is to provide a printing ink that can improve the fluorescence intensity of the reference emission wavelength by improving the energy efficiency.

  The second problem of this multiple fluorescent color material is to achieve energy efficiency improvement by focusing on the absorption spectrum exhibited by the first color material and the fluorescence emission emitted by the second color material generated by the provision of the reference excitation wavelength. Another object of the present invention is to provide a printing ink capable of improving the fluorescence intensity at the reference emission wavelength.

  The third problem of this multi-fluorescent colorant is based on the knowledge obtained by structural analysis of fluorescent dyes (that is, the amount of fluorescent dye added can be increased by rationally preventing the association of fluorescent dyes). An object of the present invention is to provide a printing ink capable of improving the fluorescence intensity of the wavelength.

  In addition to the third problem, the fourth problem of the multiple fluorescent color materials is to obtain the fluorescence emission emitted from the second color material generated by the provision of the reference excitation wavelength and the reference emission fluorescence wavelength of the first color material. Focusing on the fact that it is involved in the excitation wavelength characteristic, it is to provide a printing ink capable of improving the fluorescence intensity of the reference emission wavelength.

  A fifth problem of the multiple fluorescent color material is to provide a printing ink that can more stably improve the fluorescence intensity of the reference emission wavelength as a characteristic of the ink itself having the multiple fluorescent color material.

  The sixth problem of this multiple fluorescent color material is that the fluorescence obtained at the reference emission wavelength is not greatly affected by the knowledge obtained by the analysis from the formed image, that is, the type and characteristics of the recording material on which the image is formed. It is to provide a printing ink capable of improving the strength.

  In addition to the first problem, the seventh problem of the multiple fluorescent color materials is based on improving the energy efficiency by focusing on the correlation between the excitation characteristics of the first color material and the absorption spectrum of the second color material. An object of the present invention is to provide a printing ink capable of improving the fluorescence intensity of the emission wavelength. In addition, the further subject and objective of this multiple fluorescent color material will become clear by the following description.

  The present invention includes a plurality of fluorescent color materials that include the following embodiments. When the wavelength relation is collectively referred to among the plurality of fluorescent color materials, the peak wavelength region (see FIG. 23) of the excitation wavelength characteristic for obtaining the reference emission wavelength (for example, 600 nm) of the first fluorescent color material and / or the first The visible light absorption spectrum of the fluorescent color material (the lower side in FIG. 27) is summarized as including at least the fluorescence emission wavelength region (see FIG. 25) of the second fluorescent color material.

  First, the first aspect of the printing ink of the plurality of fluorescent color materials capable of achieving at least the first problem is a reference fluorescence wavelength used for measurement or determination, among the wavelengths that emit fluorescence by providing a reference excitation wavelength. A first fluorescent color material that emits light of the second fluorescent color material that emits fluorescence at the reference excitation wavelength, and the emission wavelength range of the second fluorescent color material is at least A peak wavelength region substantially corresponding to a peak region adjacent to the reference fluorescence wavelength in an excitation wavelength region for obtaining light emission of the reference fluorescence wavelength of the first fluorescent color material in the ink, Printing ink.

  The “peak wavelength region corresponding to the peak region adjacent to the reference fluorescence wavelength” of the fluorescence emission of the first fluorescent color material in the plurality of fluorescent color materials has a practical meaning in consideration of this energy conversion efficiency. . That is, in the “excitation wavelength spectrum for obtaining the reference fluorescence wavelength” of the first fluorescent color material, an area having an intensity of 100 or more among the peaks adjacent to the reference fluorescence wavelength is defined as a peak area, and the wavelength giving this area is defined as The peak wavelength region.

  The reference excitation wavelength is 254 nm, the peak wavelength range is 430 nm to 600 nm, and the emission wavelength range of the second fluorescent color material includes 600 nm as the reference fluorescence wavelength, and the emission wavelength range is 425 nm to 600 nm. It is preferable to have. Further, in the first aspect, the first fluorescent color material has a peak region of an absorption spectrum in a visible light region, and the peak region of the absorption spectrum in a wavelength region of fluorescence emission of the second fluorescent color material. It is preferable that a region on the lower wavelength side is included.

  The second aspect of the printing ink of the plurality of fluorescent color materials capable of achieving at least the second problem is that the emission of the reference fluorescence wavelength used for measurement or determination out of the wavelengths that emit fluorescence by providing the reference excitation wavelength. And a second fluorescent color material that emits fluorescence at the reference excitation wavelength, and the emission wavelength range of the second fluorescent color material is at least in the ink. In the excitation wavelength range for obtaining the emission of the reference fluorescence wavelength of the first fluorescent color material in the wavelength range including the main absorption wavelength range in the absorption spectrum of the first fluorescent color material, Printing ink.

  In the second aspect, the main absorption wavelength region of the first fluorescent color material is 500 nm or more and 590 nm or less, and the main emission wavelength region of the second fluorescent color material has an emission wavelength range of 450 nm or more and 600 nm or less. It is preferable. On the other hand, the second fluorescent color material in the first and second aspects is preferably a color material having a structure having a plurality of fluorescent luminophores.

  The third aspect of the printing ink of the plurality of fluorescent color materials that can achieve at least the third problem is that the emission of the reference fluorescence wavelength used for measurement or determination among the wavelengths that emit fluorescence by providing the reference excitation wavelength. And a second fluorescent color material that emits fluorescence by the reference excitation wavelength and enhances the emission intensity of the reference fluorescence wavelength, and includes the second fluorescence color material. The printing ink is characterized in that the color material has a structure having a plurality of fluorescent luminophores. In the third aspect, the emission wavelength range of the second fluorescent color material is preferably at least in the excitation wavelength range for obtaining the reference fluorescence wavelength of the first fluorescent color material in the ink. .

  The fourth aspect of the printing ink of the plurality of fluorescent color materials capable of achieving at least the fourth problem is to emit light of a reference fluorescence wavelength used for measurement or determination among the wavelengths that emit fluorescence by providing a reference excitation wavelength. A printing ink containing a first fluorescent color material to be provided, having a second fluorescent color material that emits fluorescence by the reference excitation wavelength, and the second fluorescent color material has a structure having a plurality of fluorescent luminophores. And the emission wavelength range of the second fluorescent color material has a wavelength range common to at least a part of the excitation wavelength range for obtaining the emission of the reference fluorescence wavelength of the first fluorescent color material in the ink. This is a printing ink. In the third and fourth aspects, it is preferable that the plurality of fluorescent luminophores of the second fluorescent color material each have a basic structure for fluorescent whitening, and further, the second fluorescent color material Preferably has a plurality of sulfone groups.

  In the first to fourth embodiments, the plurality of fluorescent luminophores of the second fluorescent color material are preferably dimers. On the other hand, in the first to fourth aspects, it is preferable that the second fluorescent color material is a direct dye.

  The printing ink of the third and fourth aspects is a water-based ink, and is an ink that emits fluorescence by the reference excitation wavelength in the water evaporation ink state and / or the print image state of the water-based printing ink. A first peak including emission of the reference fluorescence wavelength, and a second peak in an excitation wavelength region for obtaining emission of the reference fluorescence wavelength of the first fluorescent colorant in the ink, It is preferable that it exhibits.

  The fifth aspect of the printing ink of the multiple fluorescent color materials capable of at least achieving the fifth problem is to emit light of a reference fluorescence wavelength used for measurement or determination out of wavelengths that emit fluorescence by providing a reference excitation wavelength. A printing water-based ink comprising: a first fluorescent color material to be produced; and a second fluorescent color material that emits fluorescence at the reference excitation wavelength, wherein the water-based ink for printing is in a water evaporation ink state and / or a print image state. In order to obtain an emission spectrum of an ink that emits fluorescence by the reference excitation wavelength, a first peak including emission of the reference fluorescence wavelength and emission of the reference fluorescence wavelength of the first fluorescent colorant in the ink And a second peak in the excitation wavelength region of the printing ink. In the second aspect, it is preferable that the second fluorescent color material has a structure having a plurality of fluorescent luminophores.

  The sixth aspect of the multiple fluorescent color material printing ink capable of achieving at least the sixth problem is to emit light of a reference fluorescence wavelength used for measurement or determination out of wavelengths that emit fluorescence by providing a reference excitation wavelength. A printing ink comprising a first fluorescent dye to be produced, comprising: a second fluorescent dye that emits fluorescence by the reference excitation wavelength and enhances the emission intensity of the reference fluorescence wavelength; and a solvent. The solvent is relatively soluble in the first fluorescent dye and relatively insoluble in the second fluorescent dye, and the second fluorescent dye. And a second solvent that is highly soluble and compatible with the first solvent.

  In the sixth aspect, it is preferable that both the first fluorescent dye and the second fluorescent dye have a sulfone group, and the emission wavelength range of the second fluorescent dye is at least in the ink. It is preferable that a peak wavelength region corresponding to a peak region adjacent to the reference fluorescence wavelength is substantially included in the excitation wavelength region for obtaining the reference fluorescence wavelength of the fluorescent dye.

  In the sixth aspect, the emission wavelength range of the second fluorescent dye is at least the first fluorescence in the excitation wavelength range for obtaining the reference fluorescence wavelength of the first fluorescence dye in the ink. It is preferable that it exists in the wavelength range except the main absorption wavelength range in the absorption spectrum of dye.

  On the other hand, the printing ink of the sixth aspect is a water-based ink, and has an emission spectrum as an ink that emits fluorescence by the reference excitation wavelength in the water evaporation ink state and / or the print image state of the printing water-based ink. The first peak including the emission of the reference fluorescence wavelength and the second peak in the excitation wavelength region for obtaining the emission of the reference fluorescence wavelength of the first fluorescent color material in the ink are exhibited. Preferably there is.

  The seventh aspect of the multiple fluorescent color material printing ink capable of achieving at least the seventh problem is to emit light of a reference fluorescence wavelength used for measurement or determination, among the wavelengths that emit fluorescence by providing a reference excitation wavelength. A first fluorescent color material that includes the second fluorescent color material that emits fluorescence at the reference excitation wavelength, and the emission wavelength range of the second fluorescent color material is at least in the ink A peak wavelength region corresponding to a peak region adjacent to the reference fluorescence wavelength among excitation wavelength regions for obtaining light emission of the reference fluorescence wavelength of the first fluorescence color material; The printing ink is characterized in that a main absorption wavelength region in an absorption spectrum is located on a lower wavelength side than an excitation wavelength region for obtaining light emission of the reference fluorescence wavelength of the first fluorescent color material. In the seventh aspect, the reference excitation wavelength is 254 nm, the peak wavelength region of the first fluorescent color material is 430 nm or more and 600 nm or less, and the absorption wavelength region of the second fluorescent color material is only 440 nm or less. It is preferable.

  With respect to the first to fifth and seventh aspects of the present multiple fluorescent color material, the printing ink is relatively highly soluble in the first fluorescent dye and low in the second fluorescent dye. A first solvent that is soluble, a second solvent that is highly soluble in the second fluorescent dye and compatible with the first solvent, and is incompatible with the second solvent, and It is more preferable to have a third solvent that dissolves the second fluorescent dye. This solvent condition can further improve the fluorescence intensity in the fluorescent color materials having different fluorescent color materials.

  By using each of the printing inks described above for ink jet recording, a recorded image that is excellent in at least fluorescence intensity can be provided. The inkjet recording method of the multiple fluorescent color material exhibiting such an effect is an inkjet recording method in which ink is ejected from an ejection port and adhered to a recording material, and the ink is applied to any one of the above aspects. An ink jet recording method characterized by being an ink for printing.

  The plurality of fluorescent color materials is a printing ink including a first fluorescent color material that emits light of a reference fluorescence wavelength used for measurement or determination, among the wavelengths of fluorescence emitted by providing a reference excitation wavelength, The relationship with the second fluorescent color material that emits fluorescence by the excitation wavelength is defined as defined in each of the above inventions.

  In the present situation, the best printing ink (to be described later) related to the plurality of fluorescent color materials is a PMU value (LM-2C Luminance) described in US Pat. No. 6,176,908 when judged as a recorded image. Meter (measured with “LM 2C”) can be increased by at least 2 times (3 times for the multiple fluorescent color material inks including the above solvent conditions) than the recorded image with the conventional fluorescent ink.

  In the following, the description will be made with reference to the drawings, but when not described as a recorded image or printed matter, it is measurement data in the evaporated ink in which the produced ink is evaporated and water is dispersed in the organic solvent. The printing ink according to each aspect of the plurality of fluorescent color materials includes: a first fluorescent color material that emits light of a reference fluorescence wavelength used for measurement or determination, among the wavelengths that emit fluorescence by providing a reference excitation wavelength; A second fluorescent color material that emits fluorescence at a reference excitation wavelength and a liquid medium for dissolving or dispersing them are contained.

  As the first and second fluorescent color materials of the plurality of fluorescent color materials, those satisfying the configuration according to each of the above-described aspects are used, and any dye or pigment may be used, but the ink bleeds on the recording material. In order to satisfy a higher fluorescence intensity and higher fluorescence intensity, a dye is preferable.

  Specific examples of the dye include C.I. I. Basic Red 1, 2, 9, 12, 13, 14, 17, C.I. I. Basic violet 1, 3, 7, 10, 11: 1, 14, C.I. I. Acid Yellow 73, 184, 250, C.I. I. Acid Red 51, 52, 92, 94, C.I. I. Direct Yellow 11, 24, 26, 87, 100, 147, C.I. I. Direct Orange 26, 29, 29: 1, 46, C.I. I. Direct Red 1, 13, 17, 239, 240, 242, 254 and the like can be mentioned.

  The amount of the first and second fluorescent color materials used in the plurality of fluorescent color materials is 0.01% by mass or more and 15% by mass or less based on the total amount of ink as the total amount of the first and second fluorescent color materials. More preferably, 0.05 mass% or more and 10 mass% or less is practically preferable.

  Although it depends on the fluorescent color material, the fluorescence intensity as a printed matter may not be obtained if it is 0.01% by mass or less, and if it is used in the ink jet system, if it is 15% by mass or more, the ejection characteristics are affected. There is. Practically, the first color material is preferably selected from the range of 0.01 to 1% by mass, and technically, the second fluorescent color material is intended to further improve the excitation energy efficiency. Is more preferably contained in the ink than in the first fluorescent color material.

  In addition, the fluorescent dyes shown above include fluorescent dyes that are known to cause a phenomenon in which the fluorescence becomes weaker when the concentration exceeds a specified concentration. There is a concentration range where can be expressed. In that case, it is preferable to use it in a concentration range in which strong fluorescence intensity is expressed.

  As a means for improving the fluorescence intensity, it is preferable that the first and second fluorescent color materials have at least one of the following aspects (Aspect 1) to (Aspect 3). A combination of the first and second fluorescent color materials can be arbitrarily selected from the color materials shown above.

  As the most preferable example of the combination of the plurality of fluorescent color materials, the first fluorescent color material is C.I. I. The combination which acid red 52 and the 2nd fluorescent color material are the water-soluble fluorescent color materials A demonstrated previously is mentioned. In the following description, the reference emission wavelength used for measurement or determination is 600 nm, but this wavelength regulation may be in the entire range of 580 nm or more and 620 nm or less, or may be any wavelength within this range.

  As shown in FIG. 23, the fluorescence emission of AR52, which is the first fluorescent color material, with a reference excitation wavelength of 254 nm starts at 550 nm, has a peak at 600 nm, and has a wide fluorescent emission region up to around 675 nm. In other words, it emits light of 600 nm, which is the reference emission wavelength defined here, but emits light in the entire range from 580 nm to 620 nm. Further, the visible light absorption spectrum of AR52, which is the first fluorescent color material, starts at 460 nm and has a peak at 565 nm up to 610 nm, as shown in the lower graph of FIG.

  Since this water-soluble fluorescent colorant A has a plurality of dimer fluorescent luminophores, it has an anti-association function, and the water-soluble fluorescent colorant A itself can also improve the fluorescence intensity as the addition amount increases. It is. The water-soluble fluorescent coloring material A is a direct dye having a sulfone group and hardly soluble in water (the solubility in 98% by mass of pure water is less than 2% by mass) and good for organic solvents. It is soluble. As shown in FIG. 25, the fluorescence emission of this water-soluble fluorescent colorant A with a reference excitation wavelength of 254 nm starts from 425 nm, has a peak of 510 nm, and has a wide range of fluorescence emission region up to around 650 nm. Accordingly, as the amount of the water-soluble fluorescent color material A added is increased, the fluorescence emission intensity can be improved, and the excitation energy to the first fluorescent color material can be increased. Further, the visible light absorption of the water-soluble fluorescent colorant A is 380 nm (peak value) to 440 nm as shown in the lower graph of FIG. 27, and also has ultraviolet absorption. Therefore, even if the addition amount of the water-soluble fluorescent colorant A is considerably increased, the fluorescence emission characteristics of the compound itself, the intensity of the excitation wavelength range with respect to the first fluorescent colorant, and further the fluorescence of the first fluorescent colorant itself. The light emission characteristics are not deteriorated.

  The solvent used in the ink is preferably pure water that dissolves the first fluorescent color material and an organic solvent that dissolves the second fluorescent color material. More preferably, a surfactant is included as a liquid solvent. Due to this solvent relationship, the feature of forming a fixed image in a state where the first fluorescent color material is made into a single molecule and the feature of making the dispersed and fixed state of the second fluorescent color material and the first color material uniform are sufficient. Thus, the fluorescence emission characteristic (see FIG. 30) in the recorded image can be improved compared to the fluorescence emission characteristic (see FIG. 29) by excitation at 254 nm in the water evaporation state of the ink. Thus, the water-soluble fluorescent color material A is a preferable specific example having a structure and characteristics that solve many problems of the present multiple fluorescent color materials.

  Hereinafter, the first fluorescent color material is C.I. I. Reference emission wavelength (here, 600 nm) of the first fluorescent color material (AR52) obtained by the combination of Acid Red 52 and the second fluorescent color material being the water-soluble fluorescent color material A at the reference excitation wavelength (254 nm) Will be described while including each aspect of the plurality of fluorescent color materials.

[Aspect 1]
In the first aspect, the peak wavelength region (see FIG. 24) of the excitation wavelength characteristic for obtaining the reference emission wavelength (600 nm) of the first fluorescent color material and / or the absorption spectrum of visible light of the first fluorescent color material (see FIG. 25 lower side) is at least included in the fluorescence emission wavelength region of the second fluorescent color material. In this mode 1, the relative relationship in the wavelength region is completely complemented for the loss, or the effect of improving the efficiency is satisfied.

  First, C.I. as the first fluorescent color material. I. Acid Red 52 (AR52) is dissolved in an aqueous solution (organic solvent such as glycerin and pure water) in a predetermined amount (0.3% by mass with respect to the solution in this example), and then water is completely evaporated at 60 ° C. Ink obtained (hereinafter referred to as evaporated ink) was prepared. When this evaporated ink is excited at 254 nm with a measuring instrument (FP750 manufactured by JASCO Corporation), the fluorescence emission of FIG. 23 is generated, and the excitation wavelength for obtaining the reference emission wavelength of 600 nm is expressed as its absorption spectrum. This is as shown in FIG.

  FIG. 24 shows that there is a peak region having a peak near 265 nm and a peak region having a peak near 360 nm in the wavelength region of 380 nm or less of the ultraviolet light region, and there is one peak region in the visible light region. ing. Since the wavelength of ultraviolet light excitation generally used for determination is 254 nm or 365 nm, the following was obtained when energy conversion efficiency was examined.

  That is, it was confirmed that the excitation intensity indicated by the vertical axis is 100 and a certain effect can be confirmed, and that the intensity suitable for determination is effectively shown. Therefore, the “peak wavelength region corresponding to the peak region adjacent to the reference fluorescence wavelength” of the fluorescence emission of the first fluorescent color material in the plurality of fluorescent color materials has a practical meaning in consideration of this energy conversion efficiency. It is. That is, in the “excitation wavelength spectrum for obtaining the reference fluorescence wavelength (FIG. 24)” of the first fluorescent color material, the region having the intensity of 100 or more in the spectrum having the peak adjacent to the reference fluorescence wavelength is selected. The peak region is a wavelength that gives this region.

  Therefore, in FIG. 24, when the reference fluorescence wavelength of AR52 is 600 nm (reference excitation wavelength: 254 nm), this peak wavelength region is 430 nm to 600 nm, preferably 475 nm to 600 nm. On the other hand, as shown in FIG. 25, the water-soluble fluorescent colorant A as the second fluorescent colorant has a wavelength range of 430 nm to 600 nm in the peak wavelength region when excited at the reference excitation wavelength. Including a broad range of main fluorescent emission regions from at least 450 nm to 600 nm. Of course, even when the intensity is set to 100, it can be understood from the above drawings that the water-soluble fluorescent colorant A emits fluorescence that satisfies the range.

  FIG. 26 is a graph in which the excitation wavelength spectrum of the first fluorescent color material (FIG. 24) and the wavelength spectrum of fluorescence emission of the second fluorescent color material (FIG. 25) are superimposed. It is a graph which shows the relationship between a fluorescence emission wavelength characteristic and the excitation wavelength for obtaining 600 nm light emission of AR52. As can be understood from FIG. 26, the wavelength (510 nm) indicating the maximum light emission intensity of the water-soluble fluorescent colorant A has an emission intensity of 800 with reference to the wavelength (600 nm) indicating the maximum light emission intensity of AR52 in FIG. It is more effective as shown above. This can be better understood with reference to these figures. Therefore, since the peak wavelength region of the first fluorescent color material is included in the light emission region of the second fluorescent color material, energy conversion can be performed efficiently, and the fluorescence intensity of the reference fluorescence wavelength can be obtained simply by giving the reference excitation wavelength. However, it can improve synergistically.

  Next, the item to be considered as the loss surface is the absorption spectrum of the color material to be used. FIG. 27 is a graph in which the excitation spectrum of AR52 (upper graph) for obtaining fluorescence emission at 600 nm and the absorption spectrum of the water-soluble fluorescent colorant A (lower graph) are vertically compared at the same wavelength. Here, absorption and excitation cannot be compared numerically, but a relative relationship can be seen. In general, the absorption spectrum has a part of the emission wavelength range, but is lower than the emission wavelength. The absorption spectrum of the water-soluble fluorescent colorant A also has a part of the fluorescence emission wavelength region shown in FIG. 25, and has an absorption spectrum at 440 nm or less. Since the absorption spectrum also has a practically effective range in the vicinity of the peak, the maximum absorption wavelength (380 nm) of the water-soluble fluorescent colorant A in the main excitation wavelength range (425 nm to 600 nm) of AR52 having a fluorescence intensity of 100 or more. It is preferable that the vicinity does not exist, and further that the wavelength region (425 nm or less) of the main absorption spectrum does not exist. In any case, since this absorption spectrum has no range overlapping the peak wavelength region, it does not directly affect the energy conversion.

  In any case, since this absorption spectrum has no range overlapping the peak wavelength region, it does not directly affect the energy conversion. If the ratio of the light emission of the second fluorescent color material corresponding to the excitation wavelength region of the first fluorescent color material is absorbed in this absorption spectrum is large, it can be determined that there is a loss in improving the fluorescence intensity.

  The wavelength range of fluorescence emission of the water-soluble fluorescent colorant A is in an effective excitation wavelength range for obtaining the reference emission wavelength of AR52, and the emission generated from the water-soluble fluorescent colorant A is further used for excitation of AR52. Since the absorption spectrum of the water-soluble fluorescent colorant A does not lower the efficiency, the fluorescence emission from the second fluorescent colorant becomes new excitation energy of the first fluorescent colorant, and the fluorescence can be improved. Become.

  23 and 25, the AR52 fluorescence emission wavelength region and the water-soluble fluorescent colorant A fluorescence emission wavelength region overlap at least from 580 nm to 620 nm. Is more effective for the determination by the reference emission wavelength.

  Next, the characteristics of the plurality of fluorescent color materials with respect to the absorption spectrum of the first fluorescent color material will be described. FIG. 28 is a graph in which the absorption spectrum (lower graph) originally possessed by the AR 52 and the fluorescence emission spectrum (upper graph) of the water-soluble fluorescent colorant A are combined at the same wavelength. It is preferable to consider the absorption spectrum of AR52 as a loss energy with respect to the fluorescent light emission wavelength region of the water-soluble fluorescent colorant A.

  The absorption spectrum of AR52 is 600 nm or less, has a peak in the vicinity of 560 nm, and has a main absorption in the visible light region up to 460 nm. The effective range of the absorption spectrum of AR52 is even smaller, being 500 nm or more and 590 nm or less. Considering the AR52 fluorescence emission range (550 nm or more) and their intensities shown in FIG. 23, this absorption spectrum is judged to exhibit the absorption effect in the range of 500 nm to 560 nm. Since this absorption spectrum is in the visible light region, it has been conventionally excluded from the technical discussion on the fluorescence emission of AR52.

  However, since the plurality of fluorescent color materials use a plurality of different fluorescent color materials, this absorption spectrum is a point to be considered for the two-step excitation energy conversion. That is, when the absorption spectrum is recognized as a problem, the fluorescence emission of the second fluorescent color material is present in a wavelength range that excludes the range of the absorption spectrum and is also an excitation wavelength for obtaining the reference fluorescence wavelength. This is one of the solutions.

  FIG. 28 shows this relationship, and as can be understood from the upper and lower graphs, it can be understood that a large amount of the fluorescence emission is obtained in the range of 430 nm to 515 nm, which is hardly affected by the absorption spectrum. The wavelength region of the fluorescence emission of the water-soluble fluorescent colorant A, which is the second fluorescent colorant, is lower than the peak (560 nm) of the absorption spectrum of AR52 and the substantial absorption region (500 nm to 590 nm). The fluorescent light emitting region of the second fluorescent color material (region indicated by α in FIG. 28: 430 nm or more and less than 500 nm) is included. Since this region emits light energy having a combined intensity in the wavelength region of the second fluorescent color material and is used as excitation energy of the first fluorescent color material, the fluorescence intensity of the reference emission wavelength as a whole is enhanced. Is done. That is, at least the region α overlaps the second excitation wavelength region of the AR52 that is the first fluorescent color material, which contributes to the improvement of the fluorescence intensity of the AR52 that is the first fluorescent color material. .

  Next, as a comparative example, C.I. I. A case where Acid Yellow 73 (AY73) is combined will be described with reference to FIGS. In the figure, when ultraviolet light was applied, the evaporated ink was used, and the absorption was measured with ordinary ink. As shown in FIG. 32, AY73 emits fluorescence in a wavelength range of approximately 500 to 600 nm (peak: 530 nm) when excitation is performed at a reference excitation wavelength of 254 nm.

  FIG. 33 is a graph in which the fluorescence emission graph of AY73 in FIG. 32 is superimposed on the excitation wavelength spectrum of AR52 described in FIG. As can be seen from this figure, the fluorescence emission of AY73 generates fluorescence emission in the wavelength range of about 500 to 600 nm (peak: 530 nm), but as the range of 505 nm to 590 nm, and further to the range of 510 nm to 575 nm, both ends. The emission intensity is small, and the effective emission intensity is also narrow in the wavelength range. Compared with the above-described range of the peak region having a wavelength of 475 nm or more and 600 nm or less, the fluorescence emission of AY73 is included in the peak wavelength region. Therefore, AY73 does not emit fluorescence sufficient to cause AR52 to emit light sufficiently.

  FIG. 34 shows a comparison between the excitation spectrum of AR52 and the absorption spectrum of AY73 for obtaining fluorescence emission at 600 nm. The absorption spectrum of AY73 is in the entire visible light range of 525 nm or less and has a peak at 490 nm. Assuming that the water-soluble fluorescent color material A is an ink including AR52 and AY73 as a plurality of fluorescent examples of the present multiple fluorescent color material, the absorption spectrum of AY73 is a direction to reduce the above-described effect of the water-soluble fluorescent color material A. Act on.

  Therefore, as a multiple fluorescence example of this multiple fluorescent color material, the amount of addition of the water-soluble fluorescent color material A is increased by a desired amount (see [Aspect 2] described later) to compensate for the loss due to the absorption spectrum of AY73. good. As shown in FIG. 34, the maximum absorption wavelength (490 nm) of AY73 exists in the excitation wavelength range of AR52 (range of 450 nm to 600 nm).

  FIG. 35 is a combination of the absorption spectrum of AR52 shown in the lower graph of FIG. 28 and the fluorescence emission spectrum of AY73. As can be seen from FIG. 35, the fluorescence spectrum of AY73 is included in the substantial absorption region (500 nm or more and 590 nm or less) of the absorption spectrum of AR52, and has a light emission wavelength on a lower wavelength side than this absorption region. Absent. Therefore, the combination of only AR52 and AY73 does not disclose any configuration of the above-described multiple fluorescent color materials, nor does it provide the effect of the above-mentioned multiple fluorescent color materials.

  Returning to FIGS. 29 to 31, the multiple fluorescent color materials will be further described in terms of ink and recorded images. FIG. 29 shows a recording ink containing both AR52 and a water-soluble fluorescent colorant A, pure water and an organic solvent, and then excited by the above-mentioned FP-750 at the reference excitation wavelength of 254 nm as the above-described evaporated ink. The measurement result is displayed. FIG. 30 shows a measurement result obtained by exciting an image recorded on a recording material using the recording ink by the FP-750 with a reference excitation wavelength of 254 nm. In other words, FIG. 29 shows the result of verifying the characteristics of the recording ink of the plurality of fluorescent color materials with the evaporated ink, and FIG. 30 shows the characteristics of the recorded image by the recording ink of the plurality of fluorescent color materials. The use of the recording ink of the plurality of fluorescent color materials is proved from the recorded image.

  29 and 30 are effective in relative comparison because both use the same ink. Therefore, the effect of the present fluorescent color material is confirmed by comparing FIG. 29 and FIG. In both FIG. 29 and FIG. 30, the graph has two peaks, and the wavelengths are around 500 nm and 590 nm. As can be seen from FIGS. 23 and 25 described above, the water-soluble fluorescent colorant A gives a peak near 500 nm, and the AR52 gives a peak at 590 nm. 29 and FIG. 30, compared with FIG. 29 showing the ideal dissolved state AR52 and the water-soluble fluorescent colorant A, the recorded image has a further increased fluorescence intensity. In particular, the reference emission wavelength (600 nm or The fluorescence intensity in the entire range from 580 nm to 620 nm is increased.

  From these, each color material effectively utilizes the reference excitation wavelength in the recorded image, and the light emission of the water-soluble fluorescent color material A, which is the second fluorescent color material, and the light emission of the first fluorescent color material due to this light emission are obtained. It is proved that. In general, when fluorescent color materials are associated, the peak wavelength shifts to the longer wavelength side, but there is no such shift in the comparison between FIG. 29 and FIG.

  Therefore, the anti-association action and other technical contents of the present fluorescent color materials are proved as a result. FIG. 29 shows the result of verifying the characteristics of the recording ink of the plurality of fluorescent color materials with the evaporating ink. FIG. 30 shows the characteristics of the recorded image by the recording ink of the plurality of fluorescent color materials. The use of the fluorescent color material recording ink is proved from the recorded image.

  Furthermore, since the evaporated ink containing both the AR52 and the water-soluble fluorescent colorant A has two peaks as shown in FIG. 29, the water-soluble fluorescent colorant A also has the characteristics of the AR52 in the recording ink. It is clear that the fluorescence emission of the water-soluble fluorescent colorant A exhibits characteristics sufficient to enhance the reference emission wavelength. Further, since the recorded image also has two peaks as shown in FIG. 30, it is possible to complete a fluorescent ink that hardly causes concentration quenching and has durability to continue to increase the fluorescence intensity in the long term. Show.

  The reference fluorescence wavelength of fluorescence emission in the plurality of fluorescent color materials can be selected depending on the use of the ink and the image formed thereby. For example, the excitation spectra when the fluorescence emission wavelength (reference fluorescence wavelength) in AR52 is changed to 580, 600, and 620 are as shown in FIG.

  Therefore, a peak wavelength region that is a peak region adjacent to each reference fluorescence wavelength can be set in accordance with the plurality of fluorescent color materials. As described above, when the entire emission range from 580 nm to 620 nm is set as the reference emission wavelength, the fluorescence emission wavelength by the reference excitation wavelength of the second fluorescent color material may satisfy the peak wavelength region of most excitation spectra. preferable. However, in this case, from the effect level that is more effective than the prior art, this fluorescence emission wavelength may be one wavelength that is highly effective, and preferably satisfies the range of 5 nm or 10 nm above or around the center wavelength of 600 nm. Alternatively, the excitation spectrum may satisfy a wavelength at which reference fluorescence emission is easily obtained.

  For example, in the case of AR52, as can be seen from FIG. 31, it is more efficient to satisfy the peak wavelength region of the 600 nm excitation spectrum described above than the excitation spectra of 580 nm and 620 nm. As long as the amount of the second fluorescent color material can be increased, the effect in aspect 1 can be naturally enhanced.

[Aspect 2]
Aspect 2 relates to an ink in which the amount of the second fluorescent color material added can be increased due to the characteristic requirements in the structure of the second fluorescent color material, which has not been recognized conventionally. That is, the wavelength-related conditions listed in the aspect 1 are relaxed (it is sufficient if at least a part of the wavelength range is common to the excitation spectrum), and the energy relationship between the excitation wavelength and the emission wavelength is expressed by the second fluorescence. It can also be improved by the amount of colorant added. Specifically, the intensity of the reference emission wavelength can be increased by increasing the addition amount of the second fluorescent color material while preventing the association of the first color material by the basic structure having the color material association prevention function. Is. At least one of the first and second fluorescent color materials, preferably the first and second materials containing the basic structure of the following atoms or atomic groups and the following fluorescent luminophores in the second fluorescent color material. By using the combination of the fluorescent color materials, the intensity of the fluorescence emission at the first excitation wavelength in the first fluorescent color material can be improved.

In particular, it is preferable to have a plurality of the fluorescent luminophores in the color material structure.
That is, a color material having a plurality of fluorescent luminophores in the same molecular structure is structurally larger and more steric than a conventional fluorescent color material, and therefore has a regularity like a conventional fluorescent color material. Since certain aggregation and aggregation are less likely to occur, even if the content of the fluorescent color material in the ink is increased as compared with the conventional color material, it is difficult to reduce the fluorescence intensity. In addition, a color material having a plurality of fluorescent luminophores in the same molecular structure increases the fluorescence emission intensity because the fluorescence emission per unit molecule is increased by having a plurality of fluorescent luminophores in one molecule of the color material. I can do it. In addition, as mentioned above, it is structurally larger and stronger in three-dimensionality than conventional fluorescent color materials, so that the color materials can be easily adsorbed to the recording material components and the water resistance is good. become.

  In addition, if this fluorescent color material has directity, water resistance can be improved and it can contribute to the durability of fluorescent emission. In addition, a color material having a plurality of fluorescent luminophores in the same molecular structure is less likely to cause regular aggregation and aggregation than conventional color materials. For example, even if water in the ink evaporates, Since the aggregation of the material becomes less regular, it becomes difficult to form a strong aggregation state, so that the sticking resistance is improved. Due to this mechanism, the multiple fluorescent color material ink has good fluorescence intensity and water resistance, and the color material having a plurality of fluorescent luminophores in the same molecular structure has a strong affinity for water as a hydrophilic group. When sulfonic acid is used, the effect of the multiple fluorescent color material is further improved.

  Examples of preferable fluorescent luminophores that satisfy the above requirements and are functionally effective include aminostilbene disulfonic acid derivatives. This is also included in the structure of the water-soluble fluorescent colorant A described above.

  In the case of a conventional fluorescent color material, there is a fluorescent color material that does not increase in intensity even if its concentration in the ink is increased, but the fluorescence intensity decreases. In the case of using such a fluorescent color material, the range of applicable concentration (content in ink) is narrowed, and there is a limit in increasing the fluorescence intensity. On the other hand, when the content of the fluorescent color material is increased in the combination of the first fluorescent color material and the second fluorescent color material according to the present plurality of fluorescent color materials, which brings colored light to visible light, It is possible to further increase the fluorescence intensity according to the increase rate.

  Examples of the fluorescent luminophore having an atomic group and a group capable of exhibiting a fluorescent whitening function, which can be applied to such a plurality of fluorescent color materials, include those described above. Here, the fluorescent color material of the present multiple fluorescent color materials may be in the visible light region, although the absorption wavelength region may be in the visible light region or other than the visible light region. It is important that the color material emits fluorescent light. As shown in the above structural formula, the water-soluble fluorescent colorant A has a structure as a dimer having a plurality of fluorophores and a plurality of sulfone groups.

  The reason why the fluorescence intensity obtained by the excitation of the first fluorescent color material at the reference excitation wavelength is increased by including the fluorescent luminophore in this manner is as follows. This is because fluorescence emission is improved. In particular, aminostilbene disulfonic acid derivatives are preferable because they have a wide fluorescent emission region.

[Aspect 3]
Aspect 3 is effective for both Aspects 1 and 2, and is effective even when used alone. The first is highly soluble in the first color material and low in solubility in the second color material. And a second solvent that is highly soluble in the second color material, and a fluorescent intensity improving technique by appropriately arranging the fluorescent color material with a solvent such as a mixed solvent. Some dyes cause a chemical phenomenon called association in an attempt to keep the dye molecules stable in terms of energy.

  In the case of fluorescent dyes, the phenomenon of this association is that in the case of a dye molecule having a structure close to a plane having two or less cyclic skeletons, the two molecules face each other, and energy is replenished and lost only between the molecules. Is considered to be a factor that inhibits the fluorescence. Since this state is maintained not only in the ink but also on the paper surface, it is necessary to take measures to prevent the meeting. In general, it is known to add urea, naphthalene sulfonic acid or the like as an association inhibitor in order not to cause association. However, as long as it has fluorescence itself and can enhance the fluorescence intensity of the first fluorescent color material and has an anti-association effect itself, the fluorescence intensity is enhanced and the fluorescence efficiency is improved by preventing association. Both effects of generation can be obtained.

  Therefore, when combining the second fluorescent color material capable of increasing the fluorescence intensity of the first fluorescent color material when irradiated with the excitation light having the same excitation wavelength, the first color material is used as a solvent for the ink. On the other hand, a mixed solvent of a first solvent that is highly soluble and lowly soluble in the second color material and a second solvent that is highly soluble in the second color material is used.

  The high solubility means that the color material can be dissolved at a concentration of 3% by mass or more as a standard, and the low solubility means that the color material can be dissolved only at a concentration of less than 3% by mass as a standard. It is not possible.

  For example, when water is selected as the first solvent and glycerin is selected as the second solvent, water is highly soluble in AR52 and low in water-soluble fluorescent colorant A, Glycerin is highly soluble in the water-soluble fluorescent colorant A. Therefore, when an ink in which AR52 and the water-soluble fluorescent colorant A are contained in a solvent containing water and glycerin is prepared, the water-soluble fluorescent colorant A in the ink is in a poor solvent-excess environment, and thus weak association. It dissolves in a state and forms a stable system with AR52.

  However, when the ink is applied to the recording material, the poor solvent water quickly permeates and diffuses. In contrast, glycerin slowly permeates and diffuses in the recording material, including its high viscosity. At this time, since the water-soluble fluorescent colorant A is dissolved not in water which is a poor solvent but in glycerin which is a good solvent, diffusion permeation in the recording material also occurs slowly with glycerin.

  Furthermore, since the water-soluble fluorescent colorant A is a good solvent for glycerin, it adsorbs to the constituent components of the recording material in a monomolecular form, and thus produces good fluorescence. Furthermore, since the water-soluble fluorescent colorant A is dissolved in a monomolecular form, it also results in inhibiting the association of AR52. In other words, the water-soluble fluorescent color material A and the AR52 molecules are fixed to the recording material in a state of being appropriately mixed and dispersed with each other, and the effect of enhancing the fluorescence intensity of the AR 52 with the water-soluble fluorescent color material A is more pronounced. it is conceivable that. In this case, it is preferable that both the first fluorescent color material and the second fluorescent color material have a plurality of sulfone groups.

  Moreover, in order to preferably express the above phenomenon, the content of the fluorescent color material used is preferably not more than the content dissolved in the poor solvent used.

  On the other hand, from the viewpoint of the molecular structure of the fluorescent color material, the state where the association hardly occurs, the fluorescent color material having a structure having three or more cyclic skeletons should be at least one of the first and second water-soluble color materials. For example, the molecules of the first water-dispersed colorant and the second water-dissolved colorant do not overlap, but they are in the vicinity, making it easier to transfer energy as described above, further increasing the fluorescence. Is possible.

  Thus, the second fluorescent color material used in the present multiple fluorescent color material preferably has a plurality of fluorescent luminophores, and further has a basic structure for fluorescent whitening. preferable. Further, the plurality of fluorescent luminophores of the second fluorescent color material are preferably dimers.

  Examples of the cyclic skeleton of the second fluorescent dye include a cyclic structure including a double bond or a conjugated double bond, an aromatic ring structure, a cyclocyclic structure, or a heterocyclic structure having a heterocyclic structure, as described above. It is.

  Further, when the first fluorescent color material and the second fluorescent color material are water-soluble color materials, the water-solubilizing groups of these two fluorescent color materials are the same in order to easily inhibit the association. The solubilizing group is preferably a sulfone group that is not affected by the solubility of the ink according to pH. In the plural fluorescent color materials, for the purpose of toning and the like, as the third and subsequent color materials, in addition to the two fluorescent color materials, a fluorescent color material and a color material having no fluorescence may be contained. .

  Next, an aqueous liquid medium constituting the fluorescent ink of the present fluorescent color material together with the dye described above will be described. The aqueous liquid medium used in the plurality of fluorescent color materials preferably contains water as a main component, and the water content in the ink is 10 to 95% by mass, preferably 25% based on the total mass of the ink. It is desirable to set it to -93 mass%, More preferably, it is the range of 40-90 mass%. As the water used in the present fluorescent color material, ion exchange water is preferably used. In addition, in the ink of the present fluorescent color material, water may be used alone as an aqueous liquid medium. However, the effect of the fluorescent color material of the present invention can be more remarkable by using a water-soluble organic solvent in combination with water. You can also

  As the water-soluble organic solvent that can be used in the present fluorescent color material, the water-soluble organic solvent described above can be used, and the description thereof is omitted here. The content of the water-soluble organic solvent in the ink is generally 50% by mass or less, preferably 5 to 40% by mass, more preferably 10 to 30% by mass in total with respect to the total mass of the ink. Is desirable. Among these solvents, ethylene glycol, diethylene glycol, triethylene glycol, 2-pyrrolidone, glycerin, and 1,2,6-hexanetriol are preferably used. Moreover, it is also preferable to contain urea, ethylene urea, or trimethylolpropane as a humectant similar to the solvent in the ink of the plurality of fluorescent color materials. In particular, ethylene urea and trimethylolpropane are very suitable for the multiple fluorescent color materials. The content of these is preferably 1% by mass or more, and preferably 20% by mass or less, based on the total mass of the ink.

  The fluorescent ink of this multiple fluorescent color material configured as described above is particularly effective when used in ink jet recording. Inkjet recording methods include a recording method in which mechanical energy is applied to ink to eject droplets, and an inkjet recording method in which thermal energy is applied to ink and droplets are ejected by foaming of the ink. This method is particularly suitable for fluorescent inks of the present fluorescent material.

  Next, the multiple fluorescent color material will be described more specifically with reference to multiple fluorescent examples and reference examples. For the absorption wavelength region, the maximum absorption wavelength, and the fluorescence wavelength region, values measured with a pure water dilution of the color material were used. Absorption wavelength is measured using an absorptiometer, and when a diluted solution is prepared so that the absorbance is in the range of 0.5 to 0.7, the absorption wavelength region is defined as a region higher than the baseline as the absorption peak of the coloring material, and the peak value Was the maximum absorption wavelength. The fluorescence wavelength is measured using the diluent used for absorbance, setting the measurement conditions so that the fluorescence intensity does not exceed the measurement limit value, and fixing the excitation wavelengths of the first and second water-soluble colorants. did. The fluorescence emission wavelength region was set higher than the baseline.

  The inks in the following multiple fluorescent examples satisfy any of the configurations of the printing inks according to the first to sixth aspects described above.

Multiple fluorescence example 1
The following components were added to a predetermined concentration, and these were sufficiently mixed and stirred, followed by pressure filtration with a microfilter (manufactured by Fuji Film) having a pore size of 0.2 μm to prepare an ink.
C. I. Acid Red 52 (first fluorescent color material): 0.25 parts by mass Water-soluble fluorescent color material A (second fluorescent color material): 1 part by mass Glycerin: 7.5 parts by mass Diethylene glycol: 5 parts by mass Urea: 5 Mass part acetylenol E100 (acetylene glycol EO adduct made by Kawaken Fine Chemicals): 1 part by mass Water: 80.25 parts by mass.

  The fluorescence emission spectra and excitation spectra of the first and second fluorescent color materials were measured using a fluorescence measuring instrument FP-750 manufactured by JASCO Corporation. In order to eliminate the influence of water as a measurement sample, ink obtained by evaporating water was used.

  The absorption wavelength regions of the first and second coloring materials were measured using an absorptiometer U-3200 (trade name; manufactured by Hitachi), diluted with pure water so that the dye was diluted 100000 times. The absorption wavelength region of the first color material was 450 to 620 nm, and the maximum absorption wavelength was 565 nm. Further, the absorption wavelength region of the second color material was 300 to 450 nm, and the maximum absorption wavelength was 372 nm.

<Reference example>
The following components were added to a predetermined concentration, and these were sufficiently mixed and stirred, followed by pressure filtration with a microfilter (manufactured by Fuji Film) having a pore size of 0.2 μm to prepare an ink.
C. I. Acid Red 52 (first fluorescent colorant): 0.25 parts by mass glycerin: 7.5 parts by mass diethylene glycol: 5 parts by mass urea: 5 parts by mass acetylenol E100 (acetylene glycol EO adduct made by Kawaken Fine Chemicals): 1 mass Part water: 81.25 parts by mass.

<Evaluation>
(1) Fluorescence intensity Canon inkjet paper SW using an inkjet recording apparatus BJS600 (manufactured by Canon) having an on-demand type multi-recording head that ejects ink by applying thermal energy corresponding to the recording signal to the ink. A solid pattern of 50% Duty was printed on -101, and the fluorescence intensity was measured under the following conditions using a spectrophotometer (FP-750) manufactured by JASCO Corporation. The results were evaluated according to the following criteria and are shown in Table 1. The measurement conditions were as follows. The excitation wavelength was 254 nm, the fluorescence intensity at the maximum fluorescence wavelength was measured, and the measured fluorescence intensity value was standardized with the fluorescence intensity value of the ink of Reference Example 1 being 100. Evaluated by criteria.
A: The measured fluorescence intensity value is 150 or more.
○: The measured fluorescence intensity value is 110 or more and less than 150.
Δ: The measured fluorescence intensity value is less than 110.
(2) Color development properties Canon ink jet plain paper SW using an ink jet recording apparatus BJS600 (manufactured by Canon) having an on-demand multi-recording head that ejects ink by applying thermal energy according to a recording signal to the ink. A solid pattern of 50% Duty was printed on -101, and measurement was performed using a Macbeth RD-918 as a density measuring device for printed recorded matter.
(Double-circle): It was 0.7 or more visually readable as printed matter (circle): It was 0.5 or more and less than 0.7 readable visually as printed matter.
(Triangle | delta): It was 0.3 or more and less than 0.5 which became hard to read visually as printed matter.
X: It was less than 0.3 which cannot be read visually as printed matter.
(3) Robustness Canon inkjet inkjet plain paper SW using an inkjet recording apparatus BJS600 (manufactured by Canon) having an on-demand multi-recording head that ejects ink by applying thermal energy corresponding to the recording signal to the ink. A solid pattern of 50% Duty was printed on -101, allowed to stand for 24 hours, then immersed in tap water for 5 minutes, and the change in print density was evaluated using Macbeth RD918 according to the following criteria.
(Double-circle): The density change which can be read easily visually as printed matter was less than 50%.
A: 50% or more and less than 70% that can be visually read as printed matter.
(Triangle | delta): It was 70% or more which cannot be visually read as printed matter.

  In the multiple fluorescent examples 2 to 6 and the reference examples 2 to 3, each ink was prepared according to the composition shown in Table 2. Further, the relationship of fluorescence, excitation and absorption by the combination of the first and second color materials of the plurality of fluorescent examples 4, the relationship of fluorescence, excitation and absorption by the combination of the first and second color materials of the plurality of fluorescence examples 5, The relationship between the fluorescence, excitation, and absorption by the combination of the first and second color materials in Reference Example 3 is omitted, but can be understood from the technical description of the present multiple fluorescent color materials and the description of the reference example. In addition, although the said reference example 1 uses the combination of the conventional color material, since the solvent conditions are match | combined with the solvent conditions of this multiple fluorescent color material, it is set as the reference example.

  The above-described inks were irradiated with an excitation wavelength of 254 nm, and the fluorescence emission spectra were obtained. As described in detail with reference to FIGS. As can be seen from the comparison, effects such as two strong peaks of fluorescence intensity were observed, but such a relationship was not observed in the inks of Reference Examples 1 to 3.

  Furthermore, when the fluorescence intensity and the like were evaluated in the same manner as in the multiple fluorescence examples 1 and the reference example 1, a large difference was found as shown in Table 3 below.

  As described above, according to the plurality of fluorescent color materials, a fluorescent ink having high fluorescence intensity, high color development, and high fastness that cannot be achieved by the prior art, and an ink jet recording method using the fluorescent ink are provided. be able to.

In some cases, a non-fluorescent water-soluble colorant may be used in combination. In this case, for example, direct dyes, acid dyes, basic dyes, vat dyes and the like can be raised. Specifically, for example, direct black 168, direct black 154, direct yellow 142, direct yellow 86, direct red 227 , Direct Blue 199, Direct Yellow 142, Direct Black 195, and Food Black 1 and 2, but are not limited thereto. Water-soluble coloring materials can be used alone or in combination of two or more as required.
In some cases, among the water-soluble color materials, those having low water solubility and exhibiting pigment-like behavior may be used as water-dispersed color materials.

  The amount of the water-soluble coloring material used is not particularly limited, but is generally in the range of 0.1 to 15% by mass, more preferably 0.1 to 10% by mass with respect to the total mass of the ink. More preferably, it is 1 to 10% by mass.

  Further, as a colorant having a carboxylic acid as a water-soluble group, specifically, for example, a dimer via a highly direct dissimilar or trisazo colorant such as Direct Black 195 or Direct Black 51 or a linking group. Color materials having a structure, for example, color materials represented by the general formulas (A) to (C) in the form of free acid as shown below, are not limited thereto.

(1) Color material represented by the following general formula (A) in the form of a free acid:

[In general formula (A), Pc is a metal-containing phthalocyanine nucleus, R ¹ , R ² and R ³ are each independently H, an alkyl group, a substituted alkyl group, an alkenyl group, a substituted alkenyl group, an aralkyl group or a substituted aralkyl group. Represents. L represents a divalent organic linking group. X independently represents a carbonyl group or a group represented by the following formulas (2) to (4).

(In the formulas (2) to (4), each Z independently represents NR ₄ R ₅ , SR ₆ or OR _6, and Y in the formula (3) represents H, Cl, the above Z, SR _7. or an oR _7, E in the formula (4) are each independently _.R 4 where represents Cl or _CN, R 5, _{R 6} and _{R 7} are H, alkyl, substituted alkyl group, an aryl group, a substituted Represents an aryl group, an aralkyl group or a substituted aralkyl group, and R ₄ and R ₅ together with the nitrogen atom form a 5- or 6-membered ring.) G is a colorless organic residue substituted with 1 or 2 COSH or COOH Represents a group, and t + q is 3 or 4. ]

  As a compound represented by general formula (A), the following are mentioned, for example.

(2) Color material represented by the following general formula (B) in the form of a free acid:

[In the general formula (B), J represents the following formula.

In General Formula (B), Ar ¹ and Ar ² are each independently an aryl group or a substituted aryl group, and at least one of Ar ¹ and Ar ² is independently one substituent selected from COOH and COSH Have more. R ¹ and R ² independently represent H, an alkyl group, a substituted alkyl group, an alkenyl group or a substituted alkenyl group, L represents a divalent organic linking group, and n represents 0 or 1. X independently represents a carbonyl group or a group represented by the following formula (2), (3) or (4).

(Z in the formulas (2) to (4) independently represents NR ₃ R ₄ , SR ₅ or OR _5, and Y in the formula (3) independently represents H, Cl, the above Z , SR ₆ or OR ₆ and E in the formula (4) independently represents Cl or CN, and R ₃ , R ₄ , R ₅ and R ₆ each independently represent H, an alkyl group, or substituted alkyl. A group, an alkenyl group, a substituted alkenyl group, an aryl group, a substituted aryl group, an aralkyl group, and a substituted aralkyl group, and R ₃ or R ₄ together with the nitrogen atom forms a 5- or 6-membered ring.) ) Has at least the same number of groups selected from COOH or COSH as SO ₃ H. ]

  Specific examples of the compound represented by the general formula (B) include the following.

(3) Color material represented by the following general formula (C) in the form of a free acid:

[In the general formula (C), Ar and Ar ¹ each independently represents an aryl group or a substituted aryl group, and at least one of Ar and Ar ¹ is selected from the group consisting of a sulfone group, a carboxyl group, and a thiocarboxyl group. With selected substituents. J and J ¹ are each independently represented by the following general formula (2), (3) or (4).

(In the above formula (2), R ⁵ is selected from a hydrogen atom, an alkyl group, a substituted alkyl group, an alkoxy group, a halogen atom, CN, a ureido group, and NHCOR _{6. The} R ₆ is a hydrogen atom, an alkyl group. , A substituted alkyl group, an aryl group, a substituted aryl group, an aralkyl group, and a substituted aralkyl group, wherein T represents an alkyl group, W represents a hydrogen atom, CN, CONR ₁₀ R ₁₁ , R ₁₀ and R ₁₁ are each independently selected from a hydrogen atom, an alkyl and a substituted alkyl group, m represents an alkylene chain having 2 to 8 carbon atoms, and is selected from the formula (4 B) is selected from a hydrogen atom, an alkyl group and a carboxyl group.

In the formula (C), R ¹ , R ² , R ³ and R ⁴ are each independently selected from a hydrogen atom, an alkyl and a substituted alkyl group, L represents a divalent organic linking group, n Represents 0 or 1, and X is independently represented by a carbonyl group or the following general formula (5), (6) or (7).

(In the above formulas (5) to (7), Z is selected from OR ₇ , SR ₇ and NR ₈ R ₉ , Y is selected from a hydrogen atom, Cl, CN and Z, E is Cl and CN R ₇ , R ₈ and R ₉ each independently represent a hydrogen atom, an alkenyl group, a substituted alkenyl group, an alkyl group, a substituted alkyl group, an aryl group, a substituted aryl group, an aralkyl group or a substituted aralkyl group. In addition, R ₈ or R ₉ may form a 5- or 6-membered ring together with the nitrogen atom to which they are bonded.
And when the compound of general formula (C) does not have a sulfone group, it has a group selected from at least two carboxyl groups and a thiocarboxyl group, and the compound of general formula (C) has at least a sulfone group and It has the same number of carboxyl groups and thiocarboxyl groups as the sulfone group. ]

  Specific examples of the compound represented by the general formula (C) include the following compounds.

  Specific examples of the water-soluble organic solvent that can be used in the second color material of the present invention include methyl alcohol, ethyl alcohol, n-propyl alcohol, isopropyl alcohol, n-butyl alcohol, sec-butyl alcohol, and tert-butyl. C1-5 alkyl alcohols such as alcohol, isobutyl alcohol and n-pentanol; Amides such as dimethylformamide and dimethylacetamide; Ketones or ketoalcohols such as acetone and diacetone alcohol; Ethers such as tetrahydrofuran and dioxane Oxyethylene such as diethylene glycol, triethylene glycol, tetraethylene glycol, dipropylene glycol, tripropylene glycol, polyethylene glycol, polypropylene glycol, etc. Cypropylene addition polymers; alkylene glycols containing 2 to 6 carbon atoms such as ethylene glycol, propylene glycol, trimethylene glycol, butylene glycol, pentanediol and hexylene glycol; glycerin, trimethylolethane, triethylene Triols such as methylolpropane and 1,2,6-hexanetriol; thiodiglycol; bishydroxyethyl sulfone; ethylene glycol monomethyl (or ethyl, butyl) ether, diethylene glycol monomethyl (or ethyl, butyl) ether, triethylene glycol monomethyl Lower alkyl glycol ethers such as (or ethyl, butyl) ether; triethylene glycol dimethyl (or ethyl) ether, tetraethylene glycol Lower dialkyl glycol ethers such as rudimethyl (or ethyl) ether; alkanolamines such as monoethanolamine, diethanolamine and triethanolamine; sulfolane, N-methyl-2-pyrrolidone, 2-pyrrolidone and 1,3-dimethyl-2 -Imidazolidinone and the like. The water-soluble organic solvents as described above can be used alone or as a mixture.

  The content of these water-soluble organic solvents in the ink is generally 50% by mass or less, preferably 5 to 40% by mass, and more preferably 10 to 30% by mass with respect to the total mass of the ink. It is desirable to be in the range.

  Among these solvents, ethylene glycol, diethylene glycol, triethylene glycol, 2-pyrrolidone, glycerin, and 1,2,6-hexanetriol are preferably used.

  In addition, it is also preferable to contain urea, ethylene urea, or trimethylolpropane as a humectant similar to the solvent in the ink having the second color material of the present invention. In particular, ethylene urea and trimethylolpropane are very suitable for the second color material of the present invention. The content of these is preferably 1% by mass or more, and preferably 20% by mass or less, based on the total mass of the ink.

  In the ink having the second color material of the present invention, in addition to the above components, an antifoaming agent, a surface tension adjusting agent, a pH adjusting agent, a viscosity adjusting agent, a fluorescence for giving the ink a desired performance as required. You may mix | blend additives, such as an accelerator, antioxidant, an evaporation accelerator, a rust inhibitor, a mold inhibitor, and a chelating agent.

  The viscosity of the ink having the second color material of the present invention is preferably in the range of 0.7 to 12 cP at 25 ° C. If the viscosity of the ink is out of the above range, normal ejection may not be performed in ink jet recording, and in particular, ink exceeding 12 cP is slow to penetrate into the recording material due to its viscosity resistance, from the viewpoint of fixing properties. Is not preferred.

  The surface tension of the ink having the second color material of the present invention is preferably adjusted to a range of 20 to 60 dyne / cm at 25 ° C. If the surface tension is less than 20 dyne / cm, the force to pull back the meniscus after the droplet is ejected in ink jet recording is weak, or conversely, when the meniscus protrudes, the pull back force is relatively weak. It is not preferable because it may be embraced or the orifice may get wet and cause a twist. By using the ink as described above, the ink proposed for the second fluorescent color material of the present invention is particularly excellent as an ink used for ink jet recording compatible with plain paper, and has excellent ink storage stability, recording density, and drying. It is possible to provide ink with excellent fixing properties and printing quality.

  In particular, the fluorescent color material to be used, preferably one having a plurality of the fluorescent luminophores in the color material structure of the second fluorescent color material is preferable.

  That is, a color material having a plurality of fluorescent luminophores in the same molecular structure is structurally larger and more steric than a conventional fluorescent color material, and therefore has a regularity like a conventional fluorescent color material. Since certain aggregation and association are less likely to occur, it is expected that the fluorescence intensity can be hardly lowered even if the content of the fluorescent color material in the ink is increased as compared with the conventional color material. In addition, a color material having a plurality of fluorescent luminophores in the same molecular structure increases the fluorescence emission intensity because the fluorescence emission per unit molecule is increased by having a plurality of fluorescent luminophores in one molecule of the color material. I expect to be able to. In addition, as mentioned above, it is structurally larger and stronger in three-dimensionality than conventional fluorescent color materials, so that the color materials can be easily adsorbed to the recording material components and the water resistance is good. I expect to become. At this time, if the coloring material has directity, not only water resistance but also fluorescence emission is further improved.

  In addition, a color material having a plurality of fluorescent luminophores in the same molecular structure is less likely to cause regular aggregation and aggregation than conventional color materials. For example, even if water in the ink evaporates, Since the aggregation of the material becomes less regular and it becomes difficult to form a strong aggregation state, it is expected that the adhesion resistance will be improved.

  Due to the above mechanism, the ink of the present invention is expected to have good fluorescence intensity and water resistance, but a colorant having a plurality of fluorescent luminophores in the same molecular structure is used as a hydrophilic group with water. When a sulfonic acid having a strong affinity is used, the effect of the present invention is further improved.

Moreover, as a preferable fluorescent luminophore, a derivative of aminostilbene disulfonic acid is suitable for satisfying the above requirements. In particular,
As a liquid medium containing components such as a dispersed color material, a mixture of water and a water-soluble organic solvent is preferable. Examples of the water-soluble organic solvent include amides such as dimethylformamide and dimethylacetamide; ketones such as acetone; ethers such as tetrahydrofuran and dioxane; polyalkylene glycols such as polyethylene glycol and polypropylene glycol; ethylene glycol and propylene Alkylene glycols in which the alkylene group contains 2 to 6 carbon atoms such as glycol, butylene glycol, triethylene glycol, 1,2,6-hexanetriol, thiodiglycol, hexylene glycol, diethylene glycol; glycerin; ethylene glycol monomethyl (Or ethyl) ether, diethylene glycol monomethyl (or ethyl) ether, triethylene glycol monomethyl (or ethyl) ether, Cole lower alkyl ethers: N-methyl-2-pyrrolidone, 1,3-dimethyl-2-imidazolidinone, triethanolamine, sulfolane, dimethyl sulfoxide, 2-pyrrolidone, etc. For example, urea, ethylene urea, epsilon caprolactone, succinimide, thiourea, dimethylol urea, 2-pyrrolidone, etc. are raised, and at least one of ethylene oxide, propylene oxide and alkyl is added to these compounds as a substituent. Also good. Further, preferably, it has a cyclic structure from the viewpoint of the stability of the crystal component in the ink. The crystal-forming components can be used alone or in combination of two or more as necessary.

  Moreover, what shows a solid form in normal temperature environment can express the effect of the invention by precipitation of the crystal component of this invention satisfactorily. The normal temperature environment indicates a range of 20 ° C. to 25 ° C. In consideration of ease of use, the melting point of the crystal forming component showing a solid form in the normal temperature environment is 30 ° C. or higher, preferably 60 ° C. or higher. Those having a melting point are preferable, and more preferably, the melting point is 120 ° or more.

  The content in these inks can be selected according to the type of recording material, but is preferably 1 to 30% by mass, and more preferably 2 to 20% by mass with respect to the total mass of the ink. If the amount is too small, the effects of the present invention cannot be exhibited. If the amount is too large, when used in ink jet recording, the discharge properties are adversely affected.

  The water content in the ink is preferably selected from the range of 30 to 95% by mass. If the amount is less than 30% by mass, the solubility of the water-soluble component may not be ensured, and the viscosity of the ink increases. On the other hand, when the amount of water is more than 95% by mass, there are too many evaporation components, and sufficient fixing characteristics may not be satisfied.

  As main components of the ink of the present invention, surfactants having a characteristic that the dissolvable amount of the water-dissolving color material increases relative to the dispersible amount of the water-dispersible color material, It has the characteristic that the soluble amount of the water-soluble coloring material containing sulfonic acid as the main water-soluble group in the state of free acid is relatively larger than the dispersible amount of the water-dispersing coloring material containing water as the acid. Suitable surfactants are higher alcohol ethylene oxide adducts that are liquid in a 25 ° C. environment. Of these, preferred surfactants are nonionic and anionic surfactants. This is because the cationic color tends to lower the color development and reliability. Furthermore, it is particularly preferable to use a nonionic surfactant having 12 or more carbon atoms. This nonionic surfactant is preferably one that does not phase separate from the aqueous solution in an aqueous solution state. At this time, if a nonionic surfactant in a state of being phase-separated from the aqueous solution is used, the ink becomes unstable when converted to ink, which is not preferable. This indicates that it is preferable to use a solution that is dissolved in water or is uniformly dispersed, and in particular, a nonionic surfactant that becomes an emulsion state with respect to an aqueous solution. I found it good to choose. Furthermore, if the content of the nonionic surfactant in the ink is selected to be equal to or less than the addition amount capable of maintaining the emulsion state in the aqueous solution state, it is preferable because there is no fear of a decrease in the stability of the ink.

  Further, among the above nonionic surfactants, those suitable for the present invention are those having an HLB of 15 or less in consideration of the fixing property of the ink to the recording material. In general, when the HLB is larger than 15, the water-solubility characteristics become strong, and the ink permeability to the recording material cannot be improved.

  Further, among the surfactants which are ethylene oxide adducts of higher alcohols used in the present invention and are liquid in an environment of 25 ° C., those having a small difference between dynamic interfacial tension and static interfacial tension are Since the alignment speed to the interface is fast, the ink liquid medium can be diffused quickly on and inside the recording material. Furthermore, when a water-dispersed color material is used in the present invention, the above-mentioned surfactant is likely to quickly adsorb to the water-dispersed color material, and therefore is oriented to a small aggregated water-dispersed color material. Because of the adsorption, it is possible to form a finely-aggregated water-dispersed color material on the recording material, which improves the effect of the present invention. Therefore, when the difference in the interfacial tension is large, it is difficult to effectively express the present invention.

  Specifically, the content of the nonionic surfactant in the ink of the present invention in the ink is preferably 0.5% by mass or more, more preferably 1 to 20% by mass with respect to the total mass of the ink. If the content is less than 0.5% by mass, the desired ink permeability and spread may not be obtained in image formation. If the content is more than 20% by mass, the desired print quality balance may be obtained. For example, there may be a case where a good balance of each performance such as image density, image fixability, and prevention of feathering, which is a whisker-like blur, may not be achieved.

  As the surfactant to be added to the surfactant which is an ethylene oxide adduct of a nonionic higher alcohol having the above-mentioned requirements and is liquid in a 25 ° C. environment, the compound represented by the following general formula (I) and the following: The compounds listed in (II) to (VII) are exemplified, but not limited thereto.

In [the above general formula (I), A and B are each _{independently, C n H 2n-1 (} n is an integer of from 1 to 10) represent, X and Y is an ethylene oxide unit and / or the ring-opened, respectively Represents a ring-opened propylene oxide unit. ]

  Of the nonionic surfactants represented by the general formula (I), a compound represented by the following general formula (VIII) is particularly preferable.

  Naturally, the use of an ethylene oxide adduct of a higher alcohol as the surfactant to be used in addition to the present invention results in a particularly excellent fluorescence emission effect of the present invention. In particular, it is preferable that the ethylene oxide adduct of a higher alcohol shows a liquid state under a normal temperature environment of 25 degrees. Moreover, what has transparency in the said normal temperature environment is also preferable. It is expected that the surfactant, which is an ethylene oxide adduct of the higher alcohol and is liquid in an environment of 25 ° C., improves the luminescent property of the color material exhibiting fluorescence.

  From the viewpoint of ink stability, the ink of the present invention preferably further contains a monohydric alcohol in the ink. Monohydric alcohol prevents the growth and generation of fungi such as molds that affect clogging and the like. Furthermore, the monohydric alcohol has a good effect on evaporation and penetration into the recording material when ink is applied on the recording material, so that the effect of the present invention can be expressed better. It is effective as The content of the monohydric alcohol in the ink of the present invention is 0.1 to 20% by mass, preferably 0.5 to 10% by mass with respect to the total mass of the ink. Specific examples of the monohydric alcohol that can be used as the ink component of the present invention include, for example, ethanol, isopropyl alcohol, and n-butanol. These may be used alone or in combination of two or more as necessary. Can be used.

  If necessary, the ink of the present invention may further comprise a water-soluble organic solvent, a rust inhibitor, a preservative, a fungicide, an antioxidant, a reduction inhibitor, an evaporation accelerator, a chelating agent, a water-soluble polymer, and a pH. You may contain various additives, such as a regulator.

  The ink of the present invention preferably has a surface tension of 40 mN / m or less. This is because, for example, it is preferable that the droplets have a spread after recording to exhibit the mechanism described above. The pH of the ink of the present invention is preferably 6.5 or more from the viewpoint of ink stability.

Furthermore, the ink of the present invention preferably uses a plurality of alkali metal ions in combination as a counter ion of the color material. When used in ink jet recording, if both are used in combination, ink stability and ink ejection properties are improved. Examples of alkali metal ions include Li ⁺ , Na ⁺ , K ^{+ and the} like.

  As a method and apparatus suitable for performing recording using the ink of the present invention, there is a method and apparatus for applying thermal energy corresponding to a recording signal to ink in a recording head chamber and generating droplets by the thermal energy. Can be mentioned.

  The water-based ink of the present invention configured as described above can be used as an ink for ordinary stationery, but is particularly effective when used in ink jet recording. Ink jet recording methods include a recording method in which mechanical energy is applied to ink to eject droplets, and an ink jet recording method in which thermal energy is applied to ink and ink droplets are ejected by foaming of the ink. It is suitable for application to an ink jet recording method in which ink is ejected due to ink bubbling due to energy, and is characterized in that ejection is extremely stable and no satellite dots are generated. However, in this case, thermal physical property values (for example, specific heat, thermal expansion coefficient, thermal conductivity, etc.) may be adjusted.

  Furthermore, the ink of the present invention solves the problem of water resistance of the ink of the printed matter when recorded on plain paper, etc., and at the same time, the physical properties of the ink itself at 25 ° C. It is desirable to adjust the surface tension to 30 to 40 mN / m and the viscosity to 15 cP or less, preferably 10 cP or less, more preferably 5 cP or less. Therefore, in order to adjust the ink to the above physical properties and solve the problem in plain paper, the amount of water contained in the ink of the present invention is 50% by mass or more and 98% by mass or less, preferably 60% by mass or more and 95%. It is preferable to set it as the mass% or less.

  On the other hand, the crystal forming component contained in the ink of the present invention is composed of a substance that is solid and water-soluble in a normal temperature environment. This substance itself is a crystalline substance, and has crystallinity such as a needle shape and a spherical shape. It has what it has and dissolves when added to water. Further, when the water content is reduced from an aqueous solution containing the substance by heating or the like, crystals are formed again. Examples of this substance include urea, ethylene urea, ε-caprolactone, succinimide, thiourea, dimethylolurea, and 2-pyrrolidone, and these compounds are substituted with at least one of ethylene oxide, propylene oxide, and alkyl. It may be added as a group. Further, preferably, it has a cyclic structure from the viewpoint of the stability of the crystal component in the ink. The crystal-forming components can be used alone or in combination of two or more as necessary. Moreover, what shows a solid form in normal temperature environment can express the effect of the invention by precipitation of the crystal component of this invention satisfactorily. The normal temperature environment means a range of 20 ° C. to 25 ° C. In consideration of ease of use, the crystal forming component showing a solid form in the normal temperature environment has a melting point of 30 ° C. or higher, preferably 60 ° C. Those having a melting point are preferable, and more preferably, the melting point is 120 ° or more. The content in these inks can be selected according to the type of recording material, but is preferably 1 to 30% by mass, and more preferably 2 to 20% by mass with respect to the total mass of the ink. If the amount is too small, the effect of the present invention cannot be exhibited. If the amount is too large, ejection properties are adversely affected when used in ink jet recording.

  The present invention is used for an ink jet ejection type head, and is also effective as an ink storage container in which the ink is stored or as a filling ink. In particular, the present invention provides an excellent effect in a bubble jet (registered trademark) type recording head and recording apparatus among ink jet recording methods.

  As its typical configuration and principle, for example, those performed using the basic principle disclosed in US Pat. Nos. 4,723,129 and 4,740,796 are preferable. This method can be applied to both the so-called on-demand type and the continuous type. In particular, in the case of the on-demand type, the electric circuit arranged corresponding to the sheet or liquid path holding the ink is used. By applying at least one drive signal corresponding to the recording information and giving a rapid temperature rise exceeding nucleate boiling to the heat conversion body, heat energy is generated in the electrothermal conversion body, and the heat acting surface of the recording head This is effective because the film can be boiled, and as a result, the drive signals can be made to correspond one-to-one and bubbles in the ink can be formed.

  By the growth and contraction of the bubbles, ink is ejected through the ejection openings to form at least one droplet. It is more preferable that the drive signal has a pulse shape, because the bubble growth and contraction is performed immediately and appropriately, and thus ink discharge with particularly excellent responsiveness can be achieved. As this pulse-shaped drive signal, those described in US Pat. Nos. 4,463,359 and 4,345,262 are suitable. Further excellent recording can be performed by employing the conditions described in US Pat. No. 4,313,124 of the invention relating to the temperature rise rate of the heat acting surface.

  As the configuration of the recording head, in addition to the combination configuration (linear liquid channel or right-angle liquid channel) of the discharge port, the liquid channel, and the electrothermal transducer as disclosed in each of the above-mentioned specifications, the heat acting part The present invention is also effective for configurations using US Pat. No. 4,558,333 and US Pat. No. 4,459,600, which disclose a configuration in which is disposed in a bending region. In addition, the present invention is also effective for a configuration (Japanese Patent Laid-Open No. 59-123670, etc.) in which a discharge hole is used as a discharge portion of the electrothermal transducer when common to a plurality of electrothermal transducers. .

  Furthermore, as a full-line type recording head having a length corresponding to the width of the maximum recording material that can be recorded by the recording apparatus, the length of the recording head is determined by a combination of a plurality of recording heads as disclosed in the above specification. Any of a configuration satisfying the above and a configuration as a single recording head formed integrally may be used, but the present invention can exhibit the above-described effects more effectively.

  In addition, it is mounted on the main body of the device so that it can be electrically connected to the main body of the device and supplied with ink from the main body of the device. The present invention is also effective when a cartridge type recording head is used.

  In the present invention, it is preferable to add recovery means for the recording head, preliminary auxiliary means, etc. provided as the configuration of the recording apparatus to be applied, because the effects of the present invention can be further stabilized. . Specific examples thereof include a capping unit for the recording head, a cleaning unit, a pressure or suction unit, an electrothermal converter, a heating element different from this, or a preheating unit using a combination thereof, This is a preliminary ejection mode in which ejection different from recording is performed.

  EXAMPLES Hereinafter, the present invention will be specifically described by way of examples, but these do not limit the scope of the present invention. In the text, “%” is based on mass unless otherwise specified.

  Each component shown below was mixed and sufficiently stirred to dissolve and / or disperse, followed by pressure filtration with a fluoropore filter (trade name; manufactured by Sumitomo Electric) having a pore size of 0.1 μm. Example inks were prepared respectively.

<Ink composition of Reference Example 1>
Preparation of pigment dispersion Using benzyl methacrylate, methacrylic acid and ethoxyethylene glycol methacrylate as raw materials, an ABC type block polymer having an acid value of 350 and a number average molecular weight of 5000 is prepared by a conventional method, and further neutralized with an aqueous potassium hydroxide solution Diluted with exchange water to make a homogeneous 50% aqueous polymer solution. 60 g of this 50% polymer solution, 100 g of carbon black and 340 g of ion exchange water were mixed and mechanically stirred for 0.5 hour. The mixture was then processed using a microfluidizer by passing it through the interaction chamber five times under a liquid pressure of about 10,000 psi ((about 70 Mpa)) to obtain a dispersion. The coarse particles were removed by separation treatment (12,000 rpm, 20 minutes), and the resulting dispersion had a pigment concentration of 10% and a dispersant concentration of 3.5%.
15% pigment dispersion solution prepared above
C. I. Acid Red 289 (water-soluble fluorescent colorant, hydrophilic group: sulfonic acid group) 0.1%
Glycerin 8%
Triethylene glycol 8%
Ethylene urea 9%
Surfactant of general formula (VIII) (ethylene oxide 0 mol adduct, forms agglomerated state of water-dispersed colorant) 1.5%
Pure water remaining

<Ink composition of Reference Example 2>
Preparation of pigment dispersion Using benzyl methacrylate and methacrylic acid as raw materials, an AB type block polymer having an acid value of 250 and a number average molecular weight of 3000 is prepared by a conventional method, further neutralized with an aqueous potassium hydroxide solution, and diluted with ion-exchanged water. Thus, a homogeneous 50% aqueous polymer solution was prepared. 100 g of this polymer solution, C.I. I. 100 g of Pigment Red 122 and 300 g of ion exchange water were mixed and mechanically stirred for 0.5 hour. The mixture was then processed using a microfluidizer by passing it through the interaction chamber five times under a liquid pressure of about 10,000 psi (about 70 Mpa) to obtain a dispersion. The dispersion was centrifuged (12,000 rpm, 20 minutes) to remove non-dispersed materials including coarse particles. The resulting dispersion had a pigment concentration of 10% and a dispersant concentration of 5%.
Pigment dispersion solution prepared above 6.7%
C. I. Acid Red 52 (water-soluble fluorescent colorant, hydrophilic group: sulfonic acid group) 0.05%
C. I. Acid Red 92 (water-soluble fluorescent colorant, hydrophilic group: sulfonic acid group) 0.6%
Water-soluble fluorescent colorant A (hydrophilic group: sulfonic acid group) 2%
Glycerin 7%
Ethylene urea 9%
Surfactant of the general formula (VIII) (ethylene oxide 10 mol adduct, forms agglomerated state of water-dispersed colorant) 1.2%
Pure water remaining

<Ink composition of Reference Example 3>
Cabojet 300 (water-dispersed coloring material, water-soluble group: carboxylic acid group, 15 wt% aqueous solution) 26.7%
C. I. Acid Red 52 (water-soluble fluorescent colorant, hydrophilic group: sulfonic acid group) 0.1%
Ethylene glycol 10%
Triethylene glycol 10%
Surfactant of general formula (VIII) (10 mol of ethylene oxide adduct, forming an aggregate state of water-dispersed colorant) 0.75%
Pure water remaining

<Ink composition of Example 1>
Preparation of pigment dispersion Using benzyl methacrylate and methacrylic acid as raw materials, an AB type block polymer having an acid value of 250 and a number average molecular weight of 3000 is prepared by a conventional method, further neutralized with an aqueous potassium hydroxide solution, and diluted with ion-exchanged water. Thus, a homogeneous 50% aqueous polymer solution was prepared. 100 g of this polymer solution, C.I. I. 100 g of Pigment Red 122 and 300 g of ion exchange water were mixed and mechanically stirred for 0.5 hour. The mixture was then processed using a microfluidizer by passing it through the interaction chamber five times under a liquid pressure of about 10,000 psi (about 70 Mpa) to obtain a dispersion. The dispersion was centrifuged (12,000 rpm, 20 minutes) to remove non-dispersed materials including coarse particles. The resulting dispersion had a pigment concentration of 10% and a dispersant concentration of 5%.
Pigment dispersion solution prepared above 6.7%
C. I. Acid Red 52 (water-soluble fluorescent colorant, hydrophilic group: sulfonic acid group) 0.05%
C. I. Acid Red 92 (water-soluble fluorescent colorant, hydrophilic group: sulfonic acid group) 0.6%
Water-soluble fluorescent colorant A (hydrophilic group: sulfonic acid group) 2%
Glycerin 7%
Ethylene urea 9%
C ₁₂ H ₂₅ (EO) ₇ (forms agglomerated state of water-dispersed colorant) 1.2%
[High-alcohol ethylene oxide adduct is a liquid that is liquid at 25 ° C. in the form of a higher alcohol ethylene oxide adduct and is liquid at room temperature and transparent]
Pure water remaining

<Ink composition of Example 2>
Preparation of pigment dispersion Using benzyl methacrylate and methacrylic acid as raw materials, an AB type block polymer having an acid value of 250 and a number average molecular weight of 3000 is prepared by a conventional method, further neutralized with an aqueous potassium hydroxide solution, and diluted with ion-exchanged water. Thus, a homogeneous 50% aqueous polymer solution was prepared. 100 g of this polymer solution, C.I. I. 100 g of Pigment Red 122 and 300 g of ion exchange water were mixed and mechanically stirred for 0.5 hour. The mixture was then processed using a microfluidizer by passing it through the interaction chamber five times under a liquid pressure of about 10,000 psi (about 70 Mpa) to obtain a dispersion. The dispersion was centrifuged (12,000 rpm, 20 minutes) to remove non-dispersed materials including coarse particles. The resulting dispersion had a pigment concentration of 10% and a dispersant concentration of 5%.
Pigment dispersion solution prepared above 6.7%
C. I. Acid Red 52 (water-soluble fluorescent colorant, hydrophilic group: sulfonic acid group) 0.05%
C. I. Acid Red 92 (water-soluble fluorescent colorant, hydrophilic group: sulfonic acid group) 0.6%
Water-soluble fluorescent colorant A (hydrophilic group: sulfonic acid group) 2%
Glycerin 7%
Ethylene urea 9%
C ₁₂ H ₂₅ (EO) ₁₁ (forms agglomerated state of water-dispersed colorant) 1.2%
[High-alcohol ethylene oxide adduct is a liquid that is liquid at 25 ° C. in the form of a higher alcohol ethylene oxide adduct and is liquid at room temperature and transparent]
Pure water remaining

<Ink composition of Example 3>
Preparation of pigment dispersion Using benzyl methacrylate and methacrylic acid as raw materials, an AB type block polymer having an acid value of 250 and a number average molecular weight of 3000 is prepared by a conventional method, further neutralized with an aqueous potassium hydroxide solution, and diluted with ion-exchanged water. Thus, a homogeneous 50% aqueous polymer solution was prepared. 100 g of this polymer solution, C.I. I. 100 g of Pigment Red 122 and 300 g of ion exchange water were mixed and mechanically stirred for 0.5 hour. The mixture was then processed using a microfluidizer by passing it through the interaction chamber five times under a liquid pressure of about 10,000 psi (about 70 Mpa) to obtain a dispersion. The dispersion was centrifuged (12,000 rpm, 20 minutes) to remove non-dispersed materials including coarse particles. The resulting dispersion had a pigment concentration of 10% and a dispersant concentration of 5%.
Pigment dispersion solution prepared above 6.7%
C. I. Acid Red 52 (water-soluble fluorescent colorant, hydrophilic group: sulfonic acid group) 0.05%
C. I. Acid Red 92 (water-soluble fluorescent colorant, hydrophilic group: sulfonic acid group) 0.6%
Water-soluble fluorescent colorant A (hydrophilic group: sulfonic acid group) 2%
Glycerin 7%
Ethylene urea 9%
C ₁₂ H ₂₅ (EO) ₇ (forms agglomerated state of water-dispersed colorant) 1.2%
[High-alcohol ethylene oxide adduct is a liquid that is liquid at 25 ° C. in the form of a higher alcohol ethylene oxide adduct and is liquid at room temperature and transparent]
Pure water remaining

<Ink composition of Example 4>
Preparation of pigment dispersion Using benzyl methacrylate, methacrylic acid and ethoxyethylene glycol methacrylate as raw materials, an ABC type block polymer having an acid value of 350 and a number average molecular weight of 5000 is prepared by a conventional method, and further neutralized with an aqueous potassium hydroxide solution Diluted with exchange water to make a homogeneous 50% aqueous polymer solution. 60 g of this 50% polymer solution, 100 g of carbon black and 340 g of ion exchange water were mixed and mechanically stirred for 0.5 hour. The mixture was then processed using a microfluidizer by passing it through the interaction chamber five times under a liquid pressure of about 10,000 psi ((about 70 Mpa)) to obtain a dispersion. The coarse particles were removed by separation treatment (12,000 rpm, 20 minutes), and the resulting dispersion had a pigment concentration of 10% and a dispersant concentration of 3.5%.
15% pigment dispersion solution prepared above
C. I. Acid Red 289 (water-soluble fluorescent colorant, hydrophilic group: sulfonic acid group) 0.1%
Glycerin 8%
Triethylene glycol 8%
Ethylene urea 9%
C ₁₂ H ₂₅ (EO) ₁₀ (forms agglomerated state of water-dispersed colorant) 1.5%
[High-alcohol ethylene oxide adduct is a liquid that is liquid at 25 ° C. in the form of a higher alcohol ethylene oxide adduct and is liquid at room temperature and transparent]
Pure water remaining

<Ink composition of Example 5>
Cabojet 300 (water-dispersed coloring material, water-soluble group: carboxylic acid group, 15 wt% aqueous solution) 26.7%
C. I. Acid Red 52 (water-soluble fluorescent colorant, hydrophilic group: sulfonic acid group) 0.1%
Ethylene glycol 10%
Triethylene glycol 10%
C ₁₂ H ₂₅ (EO) ₇ (forms agglomerated state of water-dispersed colorant) 0.75%
[High-alcohol ethylene oxide adduct is a liquid that is liquid at 25 ° C. in the form of a higher alcohol ethylene oxide adduct and is liquid at room temperature and transparent]
Pure water remaining

<Ink composition of Comparative Example 1>
C. I. Acid Red 52 (water-soluble fluorescent colorant, hydrophilic group: sulfonic acid group) 0.2%
C. I. Direct Black 154 (water-soluble coloring material, hydrophilic group: sulfonic acid group) 2%
Glycerin 10%
Ethylene glycol 5%
Pure water remaining

<Ink composition of Comparative Example 2>
C. I. Acid Red 52 (water-soluble fluorescent colorant, hydrophilic group: sulfonic acid group) 0.2%
C. I. Direct Black 154 (water-soluble coloring material, hydrophilic group: sulfonic acid group) 2%
Glycerin 10%
Ethylene glycol 5%
Surfactant of general formula (VIII) (ethylene oxide 10 mol adduct, dissolves the above two dyes) 1%
Pure water remaining

<Ink composition of Comparative Example 3>
Millijet Black 2000 (polymer-modified dye) 1.9%
Millijet Blue 18 (polymer-modified dye) 3%
C. I. Acid Red 52 (water-soluble fluorescent colorant, water-soluble group: sulfonic acid group) 0.4%
Pyranin 120 (water-soluble fluorescent colorant, hydrophilic group: sulfonic acid group) 1.4%
C. I. Acid Yellow 7 (water-soluble fluorescent colorant, water-soluble group: sulfonic acid group) 0.2%
Triethylene glycol monobutyl ether 4.6%
4-methylmorpholine 2.5%
Polyvinylpyrrolidone (K-12) 6%
Sodium dodecylbenzenesulfonate 1.1%
Triethanolamine 0.1%
Pure water remaining

<Ink composition of Comparative Example 4>
Pigment dispersion solution prepared in Example 10 4.3%
C. I. Acid Red 52 (water-soluble fluorescent colorant, hydrophilic group: sulfonic acid group) 0.5%
C. I. Acid Yellow 73 (water-soluble fluorescent colorant, hydrophilic group: carboxylic acid group) 0.5%
2-pyrrolidone 8%
Triethylene glycol 7%
Pure water remaining

<Ink composition of Comparative Example 5>
20% pigment dispersion solution prepared in Reference Example 2
C. I. Acid Red 52 (water-soluble fluorescent colorant, hydrophilic group: sulfonic acid group) 1%
7% ethylene glycol
Diethylene glycol 7%
Triethylene glycol 7%
2-pyrrolidone 8%
Pure water remaining

<Ink composition of Comparative Example 6>
C. I. Acid Red 52 (water-soluble fluorescent colorant, hydrophilic group: sulfonic acid group) 0.5%
C. I. Acid Yellow 7 (water-soluble fluorescent colorant, water-soluble group: sulfonic acid group) 0.5%
Glycerin 7%
7% ethylene glycol
Diethylene glycol 7%
Pure water remaining

<Ink composition of Comparative Example 7>
C. I. Food Black 2 (water-soluble fluorescent colorant, hydrophilic group: sulfonic acid group) 2%
C. I. Acid Yellow 52 (water-soluble fluorescent colorant, water-soluble group: sulfonic acid group) 0.1%
Glycerin 7%
7% ethylene glycol
Diethylene glycol 7%
Pure water remaining

<Ink composition of Comparative Example 8>
Cabojet 300 (water-dispersed coloring material, water-soluble group: carboxylic acid group, 15 wt% aqueous solution) 13.4%
C. I. Acid Yellow 52 (water-soluble fluorescent colorant, water-soluble group: sulfonic acid group) 1%
C. I. Acid Yellow 73 (water-soluble fluorescent colorant, hydrophilic group: carboxylic acid group) 1%
Glycerin 7%
7% ethylene glycol
Diethylene glycol 7%
Pure water remaining

<Evaluation>
(Color material separation evaluation 1)
Each ink of Examples and Comparative Examples was dropped onto a commercially available high quality paper from a height of 10 cm on the paper surface using a commercially available dropper, and the ink droplet change on the high quality paper was evaluated according to the following criteria.
○: A first concentrated image was formed at the center on the paper surface, and a second concentrated image was clearly formed around the entire periphery. Furthermore, diffusion of the second concentrated image was observed on the back side of the surface on which the ink droplets were dropped.
Δ: On the paper surface, a first concentrated image was formed at the center, and a second concentrated image was slightly recognized around the periphery of the first concentrated image. However, diffusion of the second concentrated image was observed on the back side of the surface on which the ink droplets were dropped.
X: A concentrated image of the first water-dispersed color material was formed in the center on the paper surface, but a concentrated image of the second water-soluble color material was not observed around the entire periphery. In addition, diffusion of the second water-soluble coloring material was also observed on the back side of the surface on which the ink droplets were dropped.
XX: A concentrated image of the first water-dispersed color material was formed at the center on the paper surface, but no concentrated image of the second water-soluble color material was observed around the entire periphery. Also, no diffusion of the second water-soluble colorant was observed on the back side of the surface on which the ink droplets were dropped.

(Coloring material separation evaluation 2)
A single dot image was printed on each ink of Examples and Comparative Examples using BJS600 (trade name; manufactured by Canon Inc.), a commercially available inkjet recording apparatus, and a commercially available ultraviolet light irradiation machine (trade name: Handy UV Lamp). SLUV-4 (manufactured by Iuchi) was visually evaluated according to the following criteria while irradiating excitation light of 254 nm with a stereomicroscope.
○: When observing the inside of the dots on the paper surface, a portion emitting fluorescence and a lot of minute aggregates not emitting fluorescence were observed. When the magnification was reduced and the periphery of the dot was observed, the periphery of the dot appeared to emit fluorescence.
(Triangle | delta): When the inside of the dot on a paper surface was observed, many fluorescence aggregation parts and the minute aggregation which is not fluorescence emission were seen. However, the fluorescence emission was weak, and the first water-dispersed color material and the second water-soluble color material were not sufficiently separated.
X: In the dots on the paper surface, no fluorescent portion was seen, and aggregated aggregates that were not fluorescent were observed.

(Evaluation of fluorescence emission 1)
Using the commercially available ultraviolet light irradiator (trade name: Handy UV Lamp SLUV-4; manufactured by uchi), the evaluation sample of the example in which the above (color material separation evaluation) was performed was irradiated with excitation light of 254 nm. The ink droplets were evaluated visually according to the following criteria.
○: On the commercially available high-quality paper side on which ink droplets were dropped, a clear fluorescence emission was observed in the concentrated image portion of the second water-dissolved color material than in the concentrated image portion of the first water-dispersed color material. Further, fluorescence emission of the second water-soluble colorant was observed on the back side of the surface on which the ink droplets were dropped.
Δ: Fluorescence emission of the second water-dissolving color material is not observed on the high-quality commercially available paper side on which the ink droplets are dropped, and almost even in the concentrated image portion of the first water-dispersed color material No fluorescence was observed. However, fluorescence emission of the second water-soluble colorant was observed on the back side of the surface on which the ink droplets were dropped.
X: The fluorescence emission of the second water-dissolving color material is not observed on the high-quality paper side on which the ink droplets are dropped, and almost even in the concentrated image portion of the first water-dispersed color material No fluorescence was observed. Further, the fluorescence emission of the second water-soluble colorant was not observed even on the back side of the surface on which the ink droplets were dropped.

(Evaluation of fluorescence emission 2)
Each ink of Examples and Comparative Examples was printed with 100% Duty solid and alphanumeric characters using BJS600 (trade name, manufactured by Canon Inc.) as a commercially available inkjet recording apparatus, and commercially available ultraviolet light irradiation. Using a machine (trade name: Handy UV Lamp SLUV-4; manufactured by Iuchi), excitation light of 254 nm was irradiated and visually evaluated according to the following criteria.
○: Fluorescence emission was clearly observed in solid, alphanumeric characters of 100% Duty.
Δ: Slight fluorescence was observed in 100% duty solid and alphanumeric characters.
X: Fluorescence emission was hardly observed in 100% duty solid and alphanumeric characters.

(Evaluation of fluorescence emission 3)
The inks of Examples and Comparative Examples were printed as 100% Duty solid and 50% solid using BJS600 (trade name; manufactured by Canon) as a commercially available inkjet recording apparatus, and a commercially available fluorescence intensity measuring device FP- 750 (trade name; manufactured by Nippon Fluorescence) was used to irradiate 254 nm excitation light, and evaluation was performed according to the following criteria.
A: The maximum fluorescence emission intensity in the visible light region (400 nm to 700 nm) was 250 or more (or better than the result obtained when the surfactant of the present invention was used).
◯: The maximum fluorescence emission intensity in the visible light region (400 nm to 700 nm) was 200 or more (less than 250).
Δ: The maximum fluorescence emission intensity in the visible light region (400 nm to 700 nm) was less than 200 and 100 or more. X: The maximum fluorescence emission intensity in the visible light region (400 nm to 700 nm) was less than 100.

(Evaluation of quality)
Using each ink of Examples and Comparative Examples as a commercially available inkjet recording apparatus, BJS600 (trade name; manufactured by Canon), images of different printing densities and alphanumeric characters as printing papers on commercially available high quality paper It printed and evaluated visually by the following reference | standard.
◯: Alphanumeric characters were well read and no graininess was seen in images with different print densities, and a smooth and good print quality was obtained.
Δ: Alphanumeric characters were well read, but graininess was observed in images with different print densities.
X: Reading of alphanumeric characters was not good, and graininess was observed in images with different printing densities.

(Evaluation of concentration)
Using the BJS600 (trade name; manufactured by Canon Inc.) as a commercially available ink jet recording apparatus, each solid ink of the example and the comparative example was printed with a solid image of 50% duty commercial high-quality paper for one day at room temperature and humidity. After sufficiently fixing, the density of the printed matter was measured using Macbeth RD918 as a density measuring device for the printed matter.
○: 1.0 or more Δ: 0.8 or more, less than 1.0 x: Less than 0.8

(Evaluation of water resistance)
Each ink of Examples and Comparative Examples was printed as a commercially available inkjet recording apparatus using a BJS600 (trade name; manufactured by Canon) on a commercially available high quality paper to print a solid image of 50% Duty and left for 24 hours. It was immersed for 5 minutes, and the change of the printing density was evaluated according to the following criteria using Macbeth RD918. Evaluation was made according to the following criteria.
○: Concentration change was less than 20%.
Δ: Density change was less than 50% to 20% or more.
X: Concentration change was 50% or more

(Contrast measurement of printed matter)
50% Duty solid images are printed on high-quality commercial paper using BJS600 (trade name; manufactured by Canon Inc.) as a commercially available inkjet recording apparatus for each of the inks of Examples 1 to 5 and Comparative Examples 1 to 3 and 6 to 8. When the reflectivity was measured with a reflection densitometer CM2002 (trade name; manufactured by Minolta) after being allowed to stand for 24 hours, the ink of the example was able to obtain sufficient contrast in the entire wavelength region of 400 nm to 700 nm. The ink of the comparative example was not sufficient. FIG. 31 shows the difference in contrast between the ink of Example 12 and Comparative Example 3.

  The results of each evaluation are shown in Table 4 below.

(Evaluation of adhesion resistance)
About 100 cc of the ink of the example was placed in a petri dish and left in an environment of temperature 25 ° C. and humidity 55% for about 1 month to evaporate the water in the ink, and then the lost water was added to re-dissolve the ink. As a result, the ink using the self-dispersing type colorant as the water-dispersed colorant re-dissolved the ink, but the one using the polymer dispersant was insufficient in re-solubility.

  In the above-described examples, the higher alcohol ethylene oxide adduct of the present invention is a liquid that is liquid in an environment at 25 ° C. (the higher alcohol ethylene oxide adduct is liquid at room temperature and transparent) and has 12 carbon atoms. However, even when the number of carbon atoms exceeds 12, if the ethylene oxide adduct is taken into consideration, it is possible to obtain a surfactant that exhibits liquid at room temperature, and it is confirmed that the effect of the present invention is exhibited. Has been.

  In addition, the ink of the present invention can obtain a sufficient contrast as shown in the (contrast measurement of printed matter) evaluation, and is exceptional (as defined in the evaluation of fluorescence emission). Thus, it is possible to provide a water-based simple fluorescent ink capable of obtaining fluorescent light emission.

It is the figure which investigated the solubility with respect to the liquid medium of a water dispersion color material. This shows a state in which the water-dispersed coloring material is separated in a floating state on the liquid medium liquid surface but is separated in a precipitated state at the bottom after a lapse of time. It is the figure which investigated the solubility with respect to the liquid medium of a water dispersion color material. It is the figure which showed the state which the water dispersion color material isolate | separated in the precipitation state on the liquid-medium liquid surface, and isolate | separates in the precipitation state on the bottom after time passage. It is the figure which investigated the solubility with respect to the liquid medium of a water dispersion color material. FIG. 4 is a diagram showing a state in which a water-dispersed coloring material is separated in a precipitated state on a liquid medium liquid surface, but diffuses throughout and becomes dissolved after a lapse of time. It is the figure which investigated the solubility with respect to the liquid medium of a water dispersion color material. FIG. 4 is a diagram showing a state in which a water-dispersed coloring material is separated in a floating state on a liquid medium liquid surface, but diffuses throughout and becomes a dissolved state after a lapse of time. It is a figure which shows typically the structure of the dot formed in the to-be-recorded material with the conventional ink. It is a figure which shows typically the structure of the dot formed in the to-be-recorded material with the ink containing the conventional several color material. It is a figure which shows typically the structure of the dot formed in the to-be-recorded material with the ink of this invention. It is a figure which shows typically the structure of the dot formed in the to-be-recorded material with the ink of this invention. It is a figure which shows typically the structure of the dot formed in the to-be-recorded material with the ink of this invention. It is a figure for demonstrating the state in which the aggregate | assembly of the water dispersion color material concerning this invention was formed when the water dispersion color material and the water soluble color material were used together. It is a figure for demonstrating typically the structure of the ink dot in the image formed with the ink of this invention. It is a figure for demonstrating typically arrangement | positioning of the ink dot in the image formed with the ink of this invention. It is a figure which shows typically arrangement | positioning of the dot formed in the to-be-recorded material with the ink of this invention. It is a figure for demonstrating formation of the aggregate in the ink of this invention. It is a figure for demonstrating formation of the aggregate of a water dispersion color material. It is a figure for demonstrating the state at the time of the aggregate | assembly of the water dispersion color material in this invention adhering to a recording material. It is a figure for demonstrating the state in which the aggregate of the water dispersion color material was formed when the water dispersion color material and the water soluble color material were used together. FIG. 3 is a diagram showing a state in which a water-soluble color material having higher solubility than the water-dispersed color material is present in a solvent in the ink in which the water-dispersed color material forms an aggregate with crystals as nuclei. It is a figure for demonstrating the state in which the aggregate | assembly of the water dispersion color material concerning this invention was formed when the water dispersion color material and the water soluble color material were used together. FIG. 10 is a diagram in which a minute aggregated color material formed on a recording material with the ink of the present invention of FIGS. 8 and 9 is observed at a magnification of 330 times. The black part is the water-dispersed color material, and the blurred part is the liquid medium. FIG. 10 is a diagram obtained by observing 132 times the finely aggregated color material formed on the recording material with the ink of the present invention of FIGS. The black part is the water-dispersed color material, and the blurred part is the liquid medium. FIG. 6 is a diagram obtained by observing the concentrated image formed on the recording material in FIG. 5 at a magnification of 330 times. The black part is the water-dispersed color material, and the blurred part is the liquid medium. It is the figure which observed the concentrated image formed in the to-be-recorded material with the ink of FIG. 5 at 132 times. The black part is the water-dispersed color material, and the blurred part is the liquid medium. C. I. It is a figure which shows the fluorescence emission spectrum whose excitation wavelength of Acid Red 52 is 254 nm. C. I. It is a figure which shows the excitation spectrum whose fluorescence emission wavelength of Acid Red 52 is 600 nm. It is a figure which shows the fluorescence emission spectrum of excitation wavelength 254nm of the water-soluble coloring material A. C. I. It is a figure which shows the contrast of the excitation spectrum whose fluorescence emission wavelength of Acid Red 52 is 600 nm, and the fluorescence emission spectrum whose excitation wavelength of water-soluble coloring material A is 254 nm. C. I. It is a figure which shows the contrast of the excitation spectrum in 600 nm fluorescence emission of Acid Red 52, and the absorption spectrum of the water-soluble coloring material A. 254 nm fluorescence emission spectrum of water-soluble colorant A; I. It is a figure which shows the contrast of the absorption spectrum of Acid Red 52. C. I. It is a figure which shows the fluorescence spectrum in the mixed ink of the acid red 52 and the water-soluble coloring material A. C. I. It is a figure which shows the fluorescence spectrum in the printed matter by the mixed ink of the acid red 52 and the water-soluble coloring material A. C. I. It is a figure which shows the excitation spectrum in 580, 600, and 620 nm of Acid Red 52. C. I. It is a figure which shows the fluorescence emission spectrum of the excitation wavelength 254nm of Acid Yellow 73. C. I. Acid Red 52 has an excitation spectrum of 600 nm in fluorescence emission wavelength and C.I. I. It is a figure which shows the contrast of the fluorescence emission spectrum whose excitation wavelength of Acid Yellow 73 is 254 nm. C. I. The excitation spectrum of Acid Red 52 at 600 nm fluorescence and C.I. I. It is a figure which shows the contrast of the absorption spectrum of Acid Yellow 73. C. I. The absorption spectrum of Acid Red 52 and C.I. I. It is a figure which shows contrast of the fluorescence emission spectrum of 254 nm of Acid Yellow 73.

Claims (22)

A first concentrated image of the first water-dispersed color material including the second water-dissolving color material is formed in the center, and the second water-dissolving is performed on the entire periphery including the surface of the recording material of the first concentrated image. A single aqueous fluorescent ink capable of forming a second concentrated image of a color material,
The aqueous simple substance fluorescent ink is relative to the first water-dispersed color material, the second water-soluble color material, the liquid medium in which these are dissolved or dispersed, water and the amount capable of dispersing the first water-dispersed color material. A higher alcohol ethylene oxide adduct capable of dissolving a large amount of the second water-soluble colorant, and containing a surfactant that is liquid in an environment at 25 ° C., and the first water-dispersed colorant and the second water A water-based simple fluorescent ink, wherein at least one of the dissolved color materials is a fluorescent color material.   The aqueous simple substance fluorescent ink according to claim 1, wherein the surfactant is an ethylene oxide adduct of a higher alcohol having 12 or more carbon atoms.   The aqueous simple substance fluorescent ink according to claim 1, wherein fluorescence emission of the second concentrated image portion is stronger than that of the first concentrated image portion.   The aqueous simple substance fluorescent ink according to claim 1, wherein the water-dispersed color material is a color material that does not emit fluorescence on the recording material, and the water-soluble color material is a color material that emits fluorescence on the recording material.   The aqueous simple substance fluorescent ink according to any one of claims 1 to 3, wherein a fluorescence emission wavelength band of the second water-soluble color material is inside an absorption wavelength band of the first water-dispersed color material.   A first concentrated image of the first water-dispersed color material containing the second water-soluble color material is formed at the center, and the higher alcohol ethylene oxide is formed on the entire periphery including the surface in the recording material of the first concentrated image. A second concentrated image of the second water-dissolving color material containing a surfactant that is a liquid under an environment of 25 ° C. as an adduct is formed, and further, a first water-dispersed color material and a second water-dissolving color A recorded image, wherein at least one of the materials is a fluorescent color material.   The fluorescence emission of the second concentrated image portion by the second water-soluble color material is stronger than that of the first concentrated image portion by the first water-dispersed color material including the second water-soluble color material. Recorded image according to.   The recorded image according to claim 6, wherein the water-dispersed color material is a color material that does not emit fluorescence on the recording material, and the water-soluble color material is a color material that emits fluorescence on the recording material.   The fluorescence emission wavelength band of the second concentrated image of the second water-dissolving color material is inside the absorption wavelength band of the first concentrated image of the first water-dispersed color material. Recorded image as described.   A water-based simple fluorescent ink capable of forming a fixing portion in which a plurality of micro-aggregated first water-dispersed color materials are scattered and arranged in the fixing portion of the second water-soluble color material, The first water-dispersed color material, the second water-soluble color material, a liquid medium that dissolves or disperses them, and water, and the first water-dispersed color material relative to the dispersible amount A higher alcohol ethylene oxide adduct capable of dissolving a large amount of the second water-soluble coloring material, containing a surfactant that is liquid in an environment at 25 ° C., and at least one of the coloring materials is a fluorescent coloring material Aqueous simplex fluorescent ink.   The aqueous simple substance fluorescent ink according to claim 9, wherein the water-dispersed color material is a color material that does not emit fluorescence on the recording material, and the water-soluble color material is a color material that emits fluorescence on the recording material.   The aqueous simple substance fluorescent ink according to any one of claims 9 to 11, wherein a fluorescence emission wavelength band of the second water-soluble color material is inside an absorption wavelength band of the first water-dispersed color material.   The fixing portion of the second water-dissolving coloring material has a fixing portion in which a plurality of finely agglomerated first water-dispersed coloring materials are arranged in a scattered manner, and is an ethylene oxide adduct of higher alcohol that is liquid in an environment of 25 ° C. A second concentrated image portion of the second water-soluble color material containing the surfactant is formed, and at least one of the first water-dispersed color material and the second water-soluble color material is a fluorescent color material. A recorded image characterized by being.   The recorded image according to claim 13, wherein the water-dispersed color material is a color material that does not emit fluorescence on the recording material, and the water-soluble color material is a color material that emits fluorescence on the recording material.   The recorded image according to any one of claims 13 to 14, wherein a fluorescence emission wavelength band of the second water-soluble colorant is inside an absorption wavelength band of the first water-dispersed colorant.   On the recording material, a first concentrated image of the first water-dispersed coloring material including the second water-soluble coloring material is formed at the center, and the entire periphery including the surface of the first concentrated image in the recording material Forming a second concentrated image of a second water-dissolved color material containing a surfactant that is liquid in an ethylene oxide adduct of a higher alcohol at 25 ° C., and the first water-dispersed color material and the second water A recording image forming method for forming an image with a plurality of dots by applying a water-based simple ink in which at least one of the dissolving color materials is a fluorescent color material, the first comprising a second water-soluble color material between the plurality of dots A recorded image forming method comprising applying a water-based simple fluorescent ink so that the first concentrated image forming portions of the water-dispersed color material are not adjacent to each other.   On the recording material, a fixing portion in which a plurality of finely agglomerated first water-dispersed coloring materials are scattered in the fixing portion of the second water-dissolving coloring material is formed, and an ethylene oxide adduct of higher alcohol is used. A second concentrated image portion of the second water-dissolving color material containing a surfactant that is liquid in an environment of 25 ° C. is formed, and the first water-dispersed color material and the second water-soluble color material A recording image forming method for forming an image with a plurality of dots by applying an aqueous simple substance fluorescent ink, at least one of which is a fluorescent color material, wherein the first water is composed of a plurality of finely aggregated water-dispersed color materials between a plurality of dots. A fluorescent recorded image forming method comprising applying a single aqueous fluorescent ink so that a fixing portion made of a dispersed color material is not adjacent.   A first concentrated image of the first water-dispersed color material containing the second water-soluble color material at the center is formed on the recording material, and is liquid in an environment of 25 ° C. with an ethylene oxide adduct of higher alcohol. A second concentrated image portion of the second water-dissolving color material containing the surfactant is formed, and the second water-dissolving color material is formed on the entire periphery including the surface of the recording material of the first concentrated image. A recorded image forming method for forming an image by applying an aqueous simple substance fluorescent ink capable of forming a second concentrated image, wherein the recorded image is formed such that the vertical resolution is different from the horizontal resolution.   On the recording material, a fixing portion in which a plurality of finely agglomerated first water-dispersed coloring materials are scattered in the fixing portion of the second water-dissolving coloring material is formed, and an ethylene oxide adduct of higher alcohol is used. A second concentrated image portion of the second water-dissolving color material containing a surfactant that is liquid in an environment of 25 ° C. is formed, and further the first water-dispersed color material and the second water-dissolving color A recording image forming method for forming an image with a plurality of dots by applying an aqueous simple substance fluorescent ink in which at least one of the materials is a fluorescent color material, comprising: the water-dispersed color material comprising a plurality of micro-aggregates between a plurality of dots. A recorded image forming method in which a single aqueous fluorescent ink is applied so that a fixing portion made of one water-dispersed color material is not adjacent to each other, and a recorded image is formed so that a vertical resolution differs from a horizontal resolution.   A water-dispersed colorant having a carboxylic acid as a main water-soluble group in a free acid state, a water-soluble colorant mainly having a sulfonic acid as a water-soluble group in a free acid state, and a carboxylic acid mainly in a free acid state It can contain a large amount of water-soluble colorant soluble in water-soluble colorant having sulfonic acid as the main water-soluble group in a free acid state relative to the dispersible amount of water-dispersible colorant having water-soluble group. A water-based simplex fluorescent ink comprising an ethylene oxide adduct of a higher alcohol, a surfactant that is liquid in an environment at 25 ° C., and water.   The aqueous simple substance fluorescent ink according to claim 20, wherein the surfactant is an ethylene oxide adduct of a higher alcohol having 12 or more carbon atoms.   The aqueous simple substance fluorescent ink according to claim 21, wherein the water-dispersed color material is a color material that does not emit fluorescence on the recording material, and the water-soluble color material is a color material that emits fluorescence on the recording material.

Images