Abstract: Ink jet recording method and apparatus is provided in which a color image is recorded by discharging, onto a recording medium, a black ink and at least one of a cyan ink, a magenta ink and a yellow ink from a black-ink recording head that ejects the black ink onto the recording medium, and a color-ink recording head that ejects the at least one of a cyan ink, a magenta ink and a yellow ink onto the recording medium, wherein the black ink contains carbon black, water, a water-soluble organic solvent, and a water-soluble polymer having an anionic functional group, and has a drying time of 5 seconds or more on the recording medium, and at least one type of the color ink contains a color material, water, a water-soluble organic solvent, and a coagulating agent, and has a drying time of 5 seconds or less on the recording medium.

Abstract: The present invention provides an intermediate transfer belt, wherein: the intermediate transfer belt is made from a resin material comprising a carbon black in a dispersed state; an absolute value of a difference between a common logarithm value of surface resistivity 10 seconds after voltage application and a common logarithm value of the surface resistivity 30 milliseconds after voltage application is about 0.2 ((Log ?/?) or less; and a Young's modulus thereof is about 3,500 MPa or more. The intermediate transfer belt is preferably formed by a process comprising: dispersing the carbon black in a polyamide acid solution to prepare a dispersant; developing the dispersant in a ring-like shape to form a developing layer; drying the developing layer to make a film to mold into a belt shape to form a molded article; and heat-treating the molded article to convert polyamide acid into imide.

Abstract: An ink set for ink jet recording including plural color inks including a black ink, the ink set including water, a water-soluble organic solvent and colorants. At least one of the color inks having a hue other than black is a specified color ink containing a compound for coagulating a colorant contained in the black ink, at least one of other color inks has a function for improving coagulability between the colorant contained in the black ink and the compound contained in the specified color ink, and the drying time of the black ink on a plain paper sheet is less than 5 seconds.

Abstract: The present invention provides an intermediate transfer belt, wherein: the intermediate transfer belt is made from a resin material comprising a carbon black in a dispersed state; an absolute value of a difference between a common logarithm value of surface resistivity 10 seconds after voltage application and a common logarithm value of the surface resistivity 30 milliseconds after voltage application is about 0.2 ((Log?/?) or less; and a Young's modulus thereof is about 3,500 MPa or more. The intermediate transfer belt is preferably formed by a process comprising: dispersing the carbon black in a polyamide acid solution to prepare a dispersant; developing the dispersant in a ring-like shape to form a developing layer; drying the developing layer to make a film to mold into a belt shape to form a molded article; and heat-treating the molded article to convert polyamide acid into imide.

Abstract: The present invention provides an ink set for ink jet recording, an ink jet recording method and an ink jet recording apparatus using the same. The ink set for ink jet recording includes a black ink and color inks including at least cyan, magenta and yellow inks. The black ink includes at least one coagulable agent, and one or more of the color inks is a coagulant-containing color ink containing a coagulant. The contact angle of each of the black ink and the color inks to a recording material is about 50° or less after 1 second of contact. The surface tension of each of the black ink and the color inks is about 40 mN/m or less. The difference between the surface tension of the black ink and that of the coagulant-containing color ink is about 5 mN/m or less.

Abstract: Ink jet recording method and apparatus is provided in which a color image is recorded by discharging, onto a recording medium, a black ink and at least one of a cyan ink, a magenta ink and a yellow ink from a black-ink recording head that ejects the black ink onto the recording medium, and a color-ink recording head that ejects the at least one of a cyan ink, a magenta ink and a yellow ink onto the recording medium, wherein the black ink contains carbon black, water, a water-soluble organic solvent, and a water-soluble polymer having an anionic functional group, and has a drying time of 5 seconds or more on the recording medium, and at least one type of the color ink contains a color material, water, a water-soluble organic solvent, and a coagulating agent, and has a drying time of 5 seconds or less on the recording medium.

Abstract: An ink set for ink jet recording including plural color inks including a black ink, the ink set including water, a water-soluble organic solvent and colorants. At least one of the color inks having a hue other than black is a specified color ink containing a compound for coagulating a colorant contained in the black ink, at least one of other color inks has a function for improving coagulability between the colorant contained in the black ink and the compound contained in the specified color ink, and the drying time of the black ink on a plain paper sheet is less than 5 seconds.

Abstract: In an aqueous ink jet recording liquid including at least water, a water-soluble organic solvent and a water-insoluble coloring material, (1) the absolute value of the zeta potential is 20 mV or more, (2) the conductivity is from 0.05 to 0.75 S/m, (3) the number average particle size of dispersed particles is from 15 to 200 nm, and (4) the number of particles having a particle size of 0.5 &mgr;m or more present in one liter is 2.5×1011 or less. Due to the aforementioned, dispersion stability of the coloring material can be maintained in the ink jet recording liquid in which the water-insoluble coloring material is dispersed, and the aqueous ink jet recording liquid is provided, which is excellent regarding stability over long periods of time, causes no ink flow route clogging and prevents kogation in printing, provides a recorded material having excellent rub resistance, printing quality, optical density, water resistance and lightfastness, and can prevent uneven density.

Abstract: An ink for ink jet printing which contains as essential components pigment, water-soluble organic solvent, and water. The ink contains particles, after ink jetting, such that the number-average particle diameter is 10 to 150 nm and the number of particles larger than 0.5 &mgr;m is 6×104 to 6×105/&mgr;l and the number of particles larger than 5 &mgr;m is less than 50/&mgr;l. This ink may be used in combination with a second liquid which contains a water-soluble organic solvent having a solubility parameter of 9 to 11, and/or surfactant, and water. A method of ink jet printing uses the ink or a combination of the ink and the liquid. The ink possesses the characteristics of both optical density and storage stability. The liquid prevents the mixing of colors of adjacent printed images.

Abstract: Disclosed is an ink for ink jet recording comprising water, a water-soluble organic solvent, a pigment and a dispersant, wherein the dispersant has a hydrophilic moiety and a hydrophobic moiety and comprises a copolymer obtained by copolymerizing from 40 to 80 mol % of a monomer having an &agr;,&bgr;-ethylenically unsaturated group constituting the hydrophilic moiety and from 20 to 60 mol % of a monomer having an &agr;,&bgr;-ethylenically unsaturated group constituting the hydrophobic moiety.

Abstract: Disclosed is an ink jet recording ink comprising water, an aqueous organic solvent, a surfactant and a self-dispersible pigment, wherein the number average particle diameter of dispersed particles of the pigment is from 15 to 100 nm, given that mv is the volumetric average particle diameter of the dispersed particles of said pigment and mn is the number average diameter of the dispersed particles of said pigment, mv/mn is less than or equal to 3, the number of particles having a particle diameter greater than or equal to 0.5 .mu.m among the dispersed particles of the pigment contained in one liter of the ink is less than or equal to 7.5.times.10.sup.10, the surface tension of the ink is less than or equal to 60 mN/m, the electroconductivity of the ink is from 0.05 to 0.4 S/m and the pH of the ink is from 6 to 11. This ink provides a high storage stability and a uniform image having high water-resistance, resolution, and density can be obtained.

Abstract: An ink jet recording ink comprising water, a coloring material, a water-soluble organic solvent and a plurality of dispersants each having a different HLB, and an ink jet recording method using this ink jet recording ink are disclosed. Preferably, given that respective HLBs of n (n.gtoreq.2) kinds of dispersants are such that HLB.sub.1 <HLB.sub.2 < . . . <HLB.sub.n, at least two dispersants satisfy the following formula:1.ltoreq.HLB.sub.x -HLB.sub.x-1 .ltoreq.30(wherein, X is an integer from 2 to n). The ink jet recording ink and ink jet recording method of the present invention do not clog a nozzle, have an excellent dispersion stability, discharge responsiveness and discharge stability, and provide uniform images having high resolution and high optical density stably.

Abstract: A multicolor ink set includes a black ink including at least a water-insoluble coloring material in which a carboxylic acid structure or a carboxylate salt structure is exposed to the surface, water, and a water-soluble organic solvent, and having a surface tension at 20.degree. C. of from 30 to 60 mN/m, and a color ink including at least one or more water-soluble coloring material selected from cyan, magenta and yellow, water, and a water-soluble organic solvent, having a surface tension at 20.degree. C. of from 20 to 50 mN/m and lower than that of the black ink, and 50% by weight or more of the water-soluble coloring material has a solubility in water at 20.degree. C. of 10% by weight or less.

Abstract: An ink jet recording ink comprising water, a coloring material such as carbon black, (a) a dispersant containing at least one of a sulfonic acid group, sulfuric ester, and salt thereof, such as a polystyrenesulfonate polymer, and (b) a dispersant above-mentioned dispersants is preferably from 0.1 to 20 parts by weight based on 10 parts by weight of the coloring material. Further, the pH, surface tension, and viscosity of the ink are preferably from 7.0 to 10.0, from 30 to 65 mN/m, and from 1.0 to 10.0 mPa.multidot.s, respectively. Dispersion stability for a long period of time is improved, kogation in the thermal ink jet method is prevented, and excellent fixation on paper is obtained containing a carboxyl group or salt thereof, such as a styrene-maleate polymer, wherein the ratio by weight of (a) to (b) is from 1:5 to 1:100.

Abstract: Ink-jet recording ink and an ink-jet recording method, said ink-jet recording ink comprising a water-insoluble coloring material, water, and at least one compound selected from the group consisting of a compound represented by formula (I) and polyglycerin: ##STR1## wherein R represents H or an alkyl group having 1 to 5 carbon atoms; m, n, o and p are all integers; and m+n+o+p is 0 to 200.

Abstract: The present invention provides an ink unit for use in an ink jet recording which can provide color images with high water resistance, no print bleeding, and an excellent color reproduction of shades, together with rub resistance, and also can render color images on ordinary paper clearly and stably, and an ink jet recording method using the ink unit, wherein the ink, unit which has a black ink and a color ink, comprises pigments, a polymeric dispersant, and water, wherein a black ink contains a black pigment and a first polymeric dispersant including a COOH group or the salt thereof (acrylic acid salts, methacrylic acid salts, and the like) and a color ink contains a chromatic pigment and a second polymeric dispersant including a SO.sub.3 H group or the salt thereof (vinyl sulfonic acid salts, naphthalene sulfonic acid salts, and styrenesulfonic acid salts).

Abstract: An ink-jet recording head cleaning method and an ink-jet recording head cleaning cartridge for use in the method are disclosed. The cartridge 3 contains a cleaning liquid comprising water and a surfactant, and an ink cartridge is replaceable therewith. In cleaning a heating head 2 of an ink-jet recording apparatus having a removable ink cartridge, the ink cartridge is replaced with the head cleaning cartridge 3 to clean the head with the cleaning liquid contained in the head cleaning cartridge. The cartridge can be packed with a cleaning liquid holder comprising either a porous material or a nonwoven fabric made of chemical fibers. Tho head cleaning method is low-cost, does not impose any limitation on ink design, is free from the problem of printing density change which occurs during long-term use, and has an advantage that ink changes are easy.

Abstract: A process for the preparation of an electrophotographic photoreceptor having a high sensitivity and stability and an excellent product quality stability without being affected by the production environment is disclosed, which comprises coating on a substrate a functional layer-forming coating solution containing a compound which undergoes polycondensation upon hydrolysis, adjusting a temperature of said substrate having the coated layer such that relationship (1) is satisfied, and then moistening said coated layer at a temperature of 30.degree. C. to 180.degree. C. in an atmosphere of a dew point of 25.degree. C. to 80.degree. C.:DP.ltoreq.ST.ltoreq.DP+40.degree. C. (1)wherein DP represents the dew point upon said moistening and ST represents the temperature of the substrate just before said moistening.

Abstract: There is disclosed a process for manufacturing an electrophotographic photoreceptor having no coating defect, a high charging performance, an excellent stability in a repeated use, and no image quality defect. The manufacturing process comprises the steps of coating a subbing layer-forming coating solution on the conductive substrate under an environment having a dew-point temperature in the range of from 5.degree. C. to 10.degree. C.; drying the coated solution under an environment having a dew-point temperature in the range of from 10.degree. C. to 20.degree. C. to prepare a subbing layer; coating a photosensitive layer-forming coating solution on the subbing layer under an environment having a dew-point temperature in the range of from 5.degree. C. to 10.degree. C.; and drying the coated solution under an environment having a dew-point temperature in the range of from 10.degree. C. to 20.degree. C. to prepare a photosensitive layer.