Abstract: Ink sets comprising an ink set A which comprises a yellow ink, a magenta ink, a cyan ink, and a black ink and an ink set B which comprises at least two inks selected from among an orange ink, a green ink, a violet ink, and a blue ink. In the ink set B, the orange ink contains an orange pigment having a cyclic structure and a basic moiety in the cyclic structure, the green ink contains a green pigment having a copper phthalocyanine structure, and the violet ink contains a violet pigment having a dioxazine skeleton. The inks included in the ink set A and ink set B each contain, as a gellant, at last one compound selected from among compounds represented by R1-CO—R2 (general formula (G1)) and compounds represented by R3-COO—R4 (general formula (G2)). In the general formulae (G1) and (G2), R1 to R4 each independently represent a C9-25 chain hydrocarbon group.

Abstract: Ink sets comprising an ink set A which comprises a yellow ink, a magenta ink, a cyan ink, and a black ink and an ink set B which comprises at least two inks selected from among an orange ink, a green ink, a violet ink, and a blue ink. In the ink set B, the orange ink contains an orange pigment having a cyclic structure and a basic moiety in the cyclic structure, the green ink contains a green pigment having a copper phthalocyanine structure, and the violet ink contains a violet pigment having a dioxazine skeleton. The inks included in the ink set A and ink set B each contain, as a gellant, at last one compound selected from among compounds represented by R1-CO—R2 (general formula (G1)) and compounds represented by R3-COO—R4 (general formula (G2)). In the general formulae (G1) and (G2), R1 to R4 each independently represent a C9-25 chain hydrocarbon group.

Abstract: An ink jet recording apparatus includes an ejector, a fixing unit, a reversing unit and a hardware processor. The ejector performs an ejection operation of ejecting a color material and an overcoat material onto a recording medium. The fixing unit fixes the overcoat material, thereby forming an overcoat on the medium. The reversing unit reverses the medium. The processor causes the fixing unit to form the overcoat on one side of the medium after causing the ejector to perform the ejection operation on the one side at a predetermined ejection position, causes the reversing unit to reverse the medium with the overcoat formed on the one side, and causes the fixing unit to form the overcoat on the other side of the medium after causing the ejector to perform the ejection operation on the other side at the ejection position.

Abstract: The present invention relates to an image forming method which includes: curing an active ray curable ink containing a gelling agent; and additionally applying and curing another active ray curable ink and by which affinity of the additionally-applied ink is further improved. The method of the present invention is an image forming method including: a first step of applying a first ink, which contains a colorant, a gelling agent, a photopolymerizable compound, and a photoinitiator, to a recording medium; a second step of irradiating the first ink with an active ray to cure and fix the first ink; a third step of additionally applying a second ink which contains a photopolymerizable compound and a photoinitiator; and a fourth step of irradiating the second ink with an active ray, in this order, wherein the first ink contains 0.5 to 5.0% by mass of the gelling agent with respect to the entire mass of the ink, the second ink contains less than 5.

Abstract: An ink jet recording apparatus includes an ejector, a fixing unit, a reversing unit and a hardware processor. The ejector performs an ejection operation of ejecting a color material and an overcoat material onto a recording medium. The fixing unit fixes the overcoat material, thereby forming an overcoat on the medium. The reversing unit reverses the medium. The processor causes the fixing unit to form the overcoat on one side of the medium after causing the ejector to perform the ejection operation on the one side at a predetermined ejection position, causes the reversing unit to reverse the medium with the overcoat formed on the one side, and causes the fixing unit to form the overcoat on the other side of the medium after causing the ejector to perform the ejection operation on the other side at the ejection position.

Abstract: Provided is a method for inkjet image formation using a line head and an activating light beam-curing type ink, characterized in that the duration from the time, from a first ink lands on a recording medium, to the time that the first ink or a second ink of the same color series as the first color lands on the recording medium, is 25 ms or longer; the ink includes a gelling agent in an amount of 0.5-3.0 mass % to the entire mass of the ink; and the complex viscosity of the ink at the temperature at which the ink lands on the recording medium is 50-300 Pa·s. According to this method, even when an inkjet image is formed at high speed using ink that experiences a sol-gel phase transition, an image free from white spots and gloss differences in the overlap areas can be formed.

Abstract: An inkjet recording method comprising: shooting to a recording medium an active-light-ray-curable inkjet ink including a photopolymerizable compound, a wax, a photopolymerization initiator, and a coloring material, and that undergoes reversible sol-gel phase transition relative to temperature; and curing the ink by irradiating an active light ray to the ink that has been shot to the recording medium, wherein the ink including a (meta) acrylate compound (B) having a molecular weight of 300-1500 and a ClogP value within the range 4.0 to 7.0, the wax content being 1.0-10 percent by mass of the total mass of the ink, and the temperature of the recording medium at active light ray irradiation being set such that the saturation solubility of the wax with respect to the ink constitutes 0.5 percent by mass or less. According to this image-forming method, blooming is suppressed.

Abstract: An active ray-curable inkjet ink which contains a photocurable compound, a photopolymerization initiator, a gelling agent and a non-polymerizable liquid compound that is in a liquid state at 25° C., with the liquid compound being contained in an amount of 15-50% by mass relative to the mass of the ink. Since droplets of this active ray-curable inkjet ink are prevented from combining with each other after landing, this active ray-curable inkjet ink is capable of providing high quality images. Meanwhile, the surface gloss of printed images is increased, and printed images having less coating film thickness difference (namely, less relief-like texture) can be formed.

Abstract: The present invention relates to an image forming method which includes: curing an active ray curable ink containing a gelling agent; and additionally applying and curing another active ray curable ink and by which affinity of the additionally-applied ink is further improved. The method of the present invention is an image forming method including: a first step of applying a first ink, which contains a colorant, a gelling agent, a photopolymerizable compound, and a photoinitiator, to a recording medium; a second step of irradiating the first ink with an active ray to cure and fix the first ink; a third step of additionally applying a second ink which contains a photopolymerizable compound and a photoinitiator; and a fourth step of irradiating the second ink with an active ray, in this order, wherein the first ink contains 0.5 to 5.0% by mass of the gelling agent with respect to the entire mass of the ink, the second ink contains less than 5.

Abstract: Provided is a method for inkjet image formation using a line head and an activating light beam-curing type ink, characterized in that the duration from the time, from a first ink lands on a recording medium, to the time that the first ink or a second ink of the same color series as the first color lands on the recording medium, is 25 ms or longer; the ink includes a gelling agent in an amount of 0.5-3.0 mass % to the entire mass of the ink; and the complex viscosity of the ink at the temperature at which the ink lands on the recording medium is 50-300 Pa·s. According to this method, even when an inkjet image is formed at high speed using ink that experiences a sol-gel phase transition, an image free from white spots and gloss differences in the overlap areas can be formed.

Abstract: The purpose of the present invention is to provide an inkjet ink degassing method that can sufficiently remove bubbles contained in active ray curable inkjet ink and improve dispensing stability and curability. The inkjet ink degassing method according to the present invention comprises a step of using hollow fibers to degas active ray curable inkjet ink that has been heated to between 60° C. and 120° C. and contains a colorant, a photopolymerizable compound, and a photoinitiator.

Abstract: Disclosed herein are an active energy ray-curable ink-jet ink that is excellent in ejection stability and does not undergo a local thermal polymerization reaction, and an image forming method using the same.

Abstract: Provided is a photocurable inkjet ink including a curable monomer, a photopolymerization initiator, a gelling agent, a colorant, and a curable oligomer. The photocurable inkjet ink is characterized in that the curable oligomer has from two to twenty functional groups, that the glass transition temperature thereof is 40.degree. C. or higher, and that the curable oligomer content is from 2 to 20% by mass relative to the mass of the ink as a whole.

Abstract: Disclosed herein are an active energy ray-curable ink-jet ink that is excellent in ejection stability and does not undergo a local thermal polymerization reaction, and an image forming method using the same.

Abstract: The purpose of the present invention is to provide an inkjet ink degassing method that can sufficiently remove bubbles contained in active ray curable inkjet ink and improve dispensing stability and curability. The inkjet ink degassing method according to the present invention comprises a step of using hollow fibers to degas active ray curable inkjet ink that has been heated to between 60° C. and 120° C. and contains a colorant, a photopolymerizable compound, and a photoinitiator.

Abstract: Provided is an actinic radiation-curable inkjet ink that undergoes sol-gel phase transfer and contains a dye, a gelling agent, a photopolymerization compound and a photopolymerization initiator. The actinic radiation-curable inkjet ink includes a photopolymerizable compound A, which is a (meth)acrylate having hydroxyl groups; a photopolymerizable compound B, which is a (meth)acrylate compound having a molecular weight within a range of 300 to 1,500 and an intramolecular structure (—CH2—CH2—O—)m (where m is an integer between 3 and 14); and a (meth)acrylate compound C, which has a molecular weight within a range of 280 to 1,500 and a C log P value within a range of 4 to 7. The ink contains, in terms of the mass of the entire ink, 1 to 15 mass % of photopolymerizable compound A, 30 to 70 mass % of photopolymerizable compound B, 10 to 40 mass % of photopolymerizable compound C, and 2 to 10 mass % of gelling agent.

Abstract: The purpose of the present invention is to provide an actinic ray curable inkjet ink which, in an inkjet printing method, is capable of having both high pinning characteristics and high ejection characteristics. In order to achieve the above purpose, this actinic ray curable inkjet ink includes an actinic ray curable compound, ketone wax, and ester wax, and reversibly goes through a sol-gel phase transition depending on the temperature.

Abstract: An active ray-curable inkjet ink which contains a photocurable compound, a photopolymerization initiator, a gelling agent and a non-polymerizable liquid compound that is in a liquid state at 25° C., with the liquid compound being contained in an amount of 15-50% by mass relative to the mass of the ink. Since droplets of this active ray-curable inkjet ink are prevented from combining with each other after landing, this active ray-curable inkjet ink is capable of providing high quality images. Meanwhile, the surface gloss of printed images is increased, and printed images having less coating film thickness difference (namely, less relief-like texture) can be formed.

Abstract: Provided are an actinic energy radiation curable ink, which can achieve a high fineness and natural glossiness when recording is carried out onto a non-absorptive recording medium such as a film or a laminated paper or a slightly absorptive recording medium such as a coated paper; and an actinic energy radiation curable inkjet recording method. This actinic energy radiation curable ink, which is to be used in inkjet recording, is characterized by: said actinic energy radiation curable ink undergoing reversible sol/gel phase transition depending on temperature; said actinic energy radiation curable ink containing from 1% or more by mass to less than 10% by mass of a gelling agent; and, at temperature Tm (° C.) that is separately defined, the storage elastic modulus (G?) of the actinic energy radiation curable ink being from 0.1 or more Pa to less than 1000 Pa and the storage elastic modulus (G?) being smaller than the loss elastic modulus (G?) thereof.

Abstract: An inkjet recording method comprising: shooting to a recording medium an active-light-ray-curable inkjet ink including a photopolymerizable compound, a wax, a photopolymerization initiator, and a coloring material, and that undergoes reversible sol-gel phase transition relative to temperature; and curing the ink by irradiating an active light ray to the ink that has been shot to the recording medium, wherein the ink including a (meta) acrylate compound (B) having a molecular weight of 300-1500 and a C log P value within the range 4.0 to 7.0, the wax content being 1.0-10 percent by mass of the total mass of the ink, and the temperature of the recording medium at active light ray irradiation being set such that the saturation solubility of the wax with respect to the ink constitutes 0.5 percent by mass or less. According to this image-forming method, blooming is suppressed.