Abstract: An azo pigment is provided which can be used as a coloring agent, etc. for use in paints, plastics, synthetic fibers, printing inks, and writing materials or for image recording or image displaying and which has performance of exhibiting high near infrared reflection/transparency, particularly when used as a heat-shielding paint, even in the case where the pigment has a dark color, and as a result, colored articles having the above-described properties are provided, and furthermore an article that is also useful as a printing ink in the security field is provided particularly when the pigment has a dark or black color. Specifically, an azo pigment is provided which is obtained through coupling reaction between a particular azo component and a particular coupling component, which has a plurality of chromophores of an azomethine group and of an azo group within a molecule, and in which the diazo component is a diazotized product of 3-(4-aminophenylimino)-1-oxo-4,5,6,7-tetrachroloisoindoline.

Abstract: An azo pigment is provided which can be used as a coloring agent, etc. for use in paints, plastics, synthetic fibers, printing inks, and writing materials or for image recording or image displaying and which has performance of exhibiting high near infrared reflection/transparency, particularly when used as a heat-shielding paint, even in the case where the pigment has a dark color, and as a result, colored articles having the above-described properties are provided, and furthermore an article that is also useful as a printing ink in the security field is provided particularly when the pigment has a dark or black color. Specifically, an azo pigment is provided which is obtained through coupling reaction between a particular azo component and a particular coupling component, which has a plurality of chromophores of an azomethine group and of an azo group within a molecule, and in which the diazo component is a diazotized product of 3-(4-aminophenylimino)-1-oxo-4,5,6,7-tetrachroloisoindoline.

Abstract: Embodiments of the present invention achieve a high linear recording density and a high track recording density to thereby improve the areal recording density in a perpendicular magnetic recording apparatus having a magnetic head that includes a trailing shield and side shields around a main magnetic pole piece.

Abstract: This present invention can provide a novel pigment useful in color image displays to form blue pixels capable of providing high-level brightness and saturation, especially a finely-divided pigment which has bright hue and is excellent in pigment physical properties such as light fastness, solvent resistance and heat resistance, and a process for producing the same, a pigment dispersion making use of the pigment, and an ink for a color filters. The novel pigment is produced by forming into a pigment a subphthalocyanine represented by the following formula (1): wherein X is a halogen atom, presents diffraction peaks at diffraction angles (2?) 7.0°, 12.3°, 20.4° and 23.4° in x-ray diffraction, and has an average particle size of 120 to 20 nm.

Abstract: A pixel-forming colorant composition contains at least one green colorant selected from the group consisting of the following pigments (A) and (B) and pigment derivative (C): (A) a copper phthalocyanine green pigment obtained by reacting at least one of a phthalic acid substituted on average with from 3.5 to 4.

Abstract: Embodiments in accordance with present invention provide a magnetic head and a magnetic disc drive capable of preventing a side erase while providing excellent recording characteristics. According to one embodiment, in order to prevent the side erase in an increased skew angle state, a first magnetic pole surface is formed in such a shape that the projection area of the first magnetic pole surface follows a track edge positioned on the boundary side in the track in the state where the first magnetic pole surface is positioned on the track at the innermost periphery thereof included in a first region. Likewise, to prevent the side erase in the increased skew angle state, a second magnetic pole surface is formed in such a shape that the projection area of the second magnetic pole surface follows a track edge positioned on the boundary side with respect to a track in the state where the second magnetic pole surface is positioned on the track at the outermost periphery thereof included in a second region.

Abstract: Embodiments of the present invention achieve a high linear recording density and a high track recording density to thereby improve the areal recording density in a perpendicular magnetic recording apparatus having a magnetic head that includes a trailing shield and side shields around a main magnetic pole piece.

Abstract: This invention provides a novel pigment, which is used, for example, in color image display devices and can form a blue pixel capable of providing a high level of bright saturation, particularly a refined pigment, which has bright hue and is excellent in pigment properties such as lightfastness, solvent resistance and heat resistance, and a process for producing the same, a pigment dispersion using the pigment, and an ink for a color filter. The novel pigment is a subphthalocyanine pigment that is prepared by converting subphthalocyanine represented by general formula (1), in which X represents a halogen atom, to a pigment, has diffraction peaks at least at diffraction angles (2?) 7.0°, 12.3°, 20.4° and 23.4° in X-ray diffraction and an average particle diameter of 120 to 20 nm.

Abstract: A water-based pigment ink contains a pigment, a hydrophilic dispersant, an aqueous medium, an alkali agent for solubilizing the hydrophilic dispersant in the aqueous medium, and a hydrophilic compound having at least one structural unit of “hydrophobic molecular chain-hydrophilic molecular chain-hydrophobic molecular chain” in a structure thereof. The water-based pigment ink is suited especially as an ink for ink-jet printers.

Abstract: Embodiments in accordance with present invention provide a magnetic head and a magnetic disc drive capable of preventing a side erase while providing excellent recording characteristics. According to one embodiment, in order to prevent the side erase in an increased skew angle state, a first magnetic pole surface is formed in such a shape that the projection area of the first magnetic pole surface follows a track edge positioned on the boundary side in the track in the state where the first magnetic pole surface is positioned on the track at the innermost periphery thereof included in a first region. Likewise, to prevent the side erase in the increased skew angle state, a second magnetic pole surface is formed in such a shape that the projection area of the second magnetic pole surface follows a track edge positioned on the boundary side with respect to a track in the state where the second magnetic pole surface is positioned on the track at the outermost periphery thereof included in a second region.

Abstract: Fluorescent colorant compositions contain a pigment and a resin. The pigment is a crystalline, azo-based, fluorescent pigment obtained from a coupling reaction of a specific diazo compound, which was obtained from a particular aromatic amine, with a particular acetoacetylamino-containing aromatic coupler. As crystalline characteristics of the crystalline, azo-based, fluorescent pigment, the ratio (h/w) of a height (h) of a maximum peak to its half-value width (w) in a diffraction angle (20) range of from 5 to 35° in an x-ray diffraction spectrum of the pigment may preferably be 20 or greater. Also disclosed are coloring processes and colored articles, which make use of the fluorescent colorant compositions.

Abstract: A pixel-forming colorant composition contains at least one green colorant selected from the group consisting of the following pigments (A) and (B) and pigment derivative (C): (A) a copper phthalocyanine green pigment obtained by reacting at least one of a phthalic acid substituted on average with from 3.5 to 4.

Abstract: A process produces a sulfonated solid particle by burning sulfur to yield gaseous sulfur dioxide, subjecting the gaseous sulfur dioxide to catalytic oxidation to yield gaseous sulfur trioxide, and sulfonating a dry powdery or granular solid particle with the gaseous sulfur trioxide in a gas phase-solid phase reaction.

Abstract: A water-based pigment ink contains a pigment, a hydrophilic dispersant, an aqueous medium, an alkali agent for solubilizing the hydrophilic dispersant in the aqueous medium, and a hydrophilic compound having at least one structural unit of “hydrophobic molecular chain-hydrophilic molecular chain-hydrophobic molecular chain” in a structure thereof. The water-based pigment ink is suited especially as an ink for ink-jet printers.

Abstract: A finely divided pigment is formed of an aggregate of primary particles. A number of primary particles of not greater than 0.1 &mgr;m in particle size is at least 95% of an entire number of the primary particles, and a number of primary particles of greater than 0.1 &mgr;m in particle size is at most 5% of the entire number of the primary particles. The finely divided pigment can be produced by grinding a parent pigment (pre-division pigment) together with a water-soluble inorganic salt and a water-soluble organic solvent in a grinding machine at a temperature of from 30 to 90° C. for 2 to 6 hours under a load, and then removing the water-soluble inorganic salt and the water-soluble organic solvent. A coloring composition comprises a dispersing medium and the finely divided pigment dispersed in the dispersing medium.

Abstract: Near-infrared transmitting black azo pigments are represented by the following formula (1) and have a crystalline form selected from the group consisting of a thin, long crystalline form and a leaf-shaped crystalline form: wherein R represents at least one group selected from the group consisting of lower alkyl groups having 1 to 3 carbon atoms and lower alkoxy groups having 1 to 3 carbon atoms, n stands for an integer of from 1 to 5, and, when n is other than 1, Rs may be the same or different. These near-infrared transmitting black azo pigments can be produced by treating the corresponding black azo pigments of the formula (1) with an alkali in an alcohol. Near-infrared transmitting black azo pigments compositions each comprises one or more of the near-infrared transmitting black azo pigments and a near-infrared transmitting material as a vehicle.

Abstract: A process produces a sulfonated solid particle by burning sulfur to yield gaseous sulfur dioxide, subjecting the gaseous sulfur dioxide to catalytic oxidation to yield gaseous sulfur trioxide, and sulfonating a dry powdery or granular solid particle with the gaseous sulfur trioxide in a gas phase-solid phase reaction.

Abstract: A finely divided pigment is formed of an aggregate of primary particles. A number of primary particles of not greater than 0.1 &mgr;m in particle size is at least 95% of an entire number of the primary particles, and a number of primary particles of greater than 0.1 &mgr;m in particle size is at most 5% of the entire number of the primary particles. The finely divided pigment can be produced by grinding a parent pigment (pre-division pigment) together with a water-soluble inorganic salt and a water-soluble organic solvent in a grinding machine at a temperature of from 30 to 90° C. for 2 to 6 hours under a load, and then removing the water-soluble inorganic salt and the water-soluble organic solvent. A coloring composition comprises a dispersing medium and the finely divided pigment dispersed in the dispersing medium.

Abstract: A near-infrared reflecting composite pigment comprises a near-infrared non-absorbing colorant and a white pigment coated with the near-infrared non-absorbing pigment. The near-infrared reflecting composite pigment can be produced by mixing a colorant dispersion, in which the near-infrared non-absorbing colorant is dispersed in a liquid medium, with the white pigment in a form selected from powder or a dispersion and then drying the resultant mixture. A near-infrared reflecting coating agent comprises as a coloring agent the near-infrared reflecting composite pigment. A near-infrared reflecting material comprises a base material coated on a surface thereof with the near-infrared reflecting coating agent.

Abstract: Pigment dispersants comprise compounds represented by the following formula (I) or (II) or metal, ammonium or amine salts thereof: wherein X1 is a hydrogen or halogen atom or an alkyl or acylamino group, Y1 is an anthraquinonylamino, phenylamino, naphthyl-amino or phenoxy group, each of R1 and R3 is a hydrogen atom or a substituted or unsubstituted alkyl or phenyl group, R2 is a substituted or unsubstituted alkylene, phenylene or naphthylene group, X2 is a hydrogen or halogen atom or a substituted or unsubstituted alkyl group, R4 is a substituted or unsubstituted phenyl or naphthyl group, and n means an average number of sulfonic acid groups introduced in said compound and stands for a number of from 0.5 to 2. Pigment compositions, such as colorants for gravure inks, paints or color filters, comprise pigments and the pigment dispersants.