Multi-color image forming material and multi-color image forming method

{
  "publication_number": "US2005112493A1",
  "country": "US",
  "kind": "A1",
  "title": "Multi-color image forming material and multi-color image forming method",
  "abstract": "To provide a multicolor image forming material in which upon irradiation with laser beam, a laser beam irradiated region of an image forming layer is transferred onto an image receiving, layer of an image receiving sheet to undergo multicolor image recording, wherein the multicolor image forming material is (a) a multicolor image forming material wherein a ratio of an optical density (OD) to a film thickness of the image forming layer of each thermal transfer sheet is 1.50 or more, a recording area of a multicolor image of each thermal transfer sheet is of a size of 515 mm×728 mm or more, a resolution of the transferred image onto the image receiving layer of the image receiving sheet is 2,400 dpi or more, a rate of heat shrinkage in the machine direction and a rate of heat shrinkage in the transverse direction of the image receiving sheet are both not more than 1%, and the rate of heat shrinkage in the transverse direction of the image receiving sheet is smaller than the rate of heat shrinkage in the machine direction thereof, (b) a multicolor image forming material wherein after laser thermal transfer, a coefficient of dynamic friction between the thermal transfer sheet surface and the image receiving sheet surface is not more than 0.70, (c) a multicolor image forming material wherein a stiffness in the machine direction (Msh) and a stiffness in the transverse direction (Tsh) of the thermal transfer sheet are both from 30 to 70 g, a stiffness in the machine direction (Msr) and a stiffness in the transverse direction (Tsr) of the image receiving sheet are both from 40 to 90 g, Msh/Tsh and Msr/Tsr are each from 0.75 to 1.20, and 10 g≦(Msr−Msh)≦40 g and 10 g≦(Tsr−Tsh)≦40 g, or (d) a multicolor image forming material wherein at least the magenta thermal transfer sheet has a breaking stress of from 150 to 300 MPa in both the machine direction (MD) and the crosswise direction (CD), with the breaking stress in the crosswise direction (CD) being at least 10 MPa larger than that in the machine direction (MD), and a breaking elongation of from 80 to 300% in both the machine direction (MD) and the crosswise direction (CD), with the breaking elongation in the machine direction (MD) being at least 5% larger than that in the crosswise direction (CD); and a multicolor image forming method using these multicolor image forming materials.",
  "claims": [
    "1. A multicolor image forming material comprising an image receiving sheet containing an image receiving layer and thermal transfer sheets of different colors of 4 or more kinds of at least yellow, magenta, cyan and black, each containing a support and at least a photothermal converting layer and an image forming layer, wherein the image forming layer of each of the thermal transfer sheets and the image receiving layer of the image receiving sheet are superposed opposite to each other, and upon irradiation with laser beam, a laser beam irradiated region of the image forming layer is transferred onto the image receiving layer of the image receiving sheet to undergo multicolor image recording, wherein: a) a ratio of an optical density (OD) to a film thickness (μm) (OD/film thickness) of the image forming layer of each of the thermal transfer sheets is 1.50 or more, b) a recording area of multicolor image of each of the thermal transfer sheets is of a size of 515 mm×728 mm or more, c) a resolution of the transferred image onto the image receiving layer of the image receiving sheet is 2,400 dpi or more, d) a rate of heat shrinkage in a machine direction (M) and a rate of heat shrinkage in a transverse direction (T) of the image receiving sheet are both not more than 1%, and e) the rate of heat shrinkage in a transverse direction (T) of the image receiving sheet is smaller than the rate of heat shrinkage in a machine direction (M) thereof. 2. The multicolor image forming material according to claim 1, wherein the image forming layer of each of the thermal transfer sheets and the image receiving layer of the image receiving sheet each has a contact angle against water in a range of from 7.0 to 120.0°. 3. The multicolor image forming material according to claim 1 or 2, wherein the ratio of an optical density (OD) to a film thickness (μm) (OD/film thickness) of the image forming layer of each of the thermal transfer sheets is 1.80 or more and that the contact angle of the image receiving sheet against water is 86° or more. 4. A multicolor image forming material comprising an image receiving sheet containing an image receiving layer and thermal transfer sheets of different colors of 4 or more kinds of at least yellow, magenta, cyan and black, each containing a support and at least a photothermal converting layer and an image forming layer, wherein after laser thermal transfer, a coefficient of dynamic friction between a surface of the thermal transfer sheet and a surface of the image receiving sheet is not more than 0.70. 5. The multicolor image forming material according to claim 4, wherein a stiffness of the image receiving sheet is 50 g or more. 6. The multicolor image forming material according to claim 4 or 5, wherein a surface electrical resistance of the image receiving layer of the image receiving sheet is not more than 1.0×10 15 Ω/sq. 7. A multicolor image forming material comprising an image receiving sheet containing an image receiving layer and thermal transfer sheets of different colors of 4 or more kinds of at least yellow, magenta, cyan and black, each containing a support and at least a photothermal converting layer and an image forming layer, wherein the image forming layer of each of the thermal transfer sheets and the image receiving layer of the image receiving sheet are superposed opposite to each other, and upon irradiation with laser beam, a laser beam irradiated region of the image forming layer is transferred onto the image receiving layer of the image receiving sheet to undergo multicolor image recording, wherein a ratio OD/T of an optical density (OD) to a layer thickness (unit: μm) of the image forming layer of each of the thermal transfer sheets is 1.50 or more; that a recording area of multicolor image of each of the thermal transfer sheets is of a size of 515 mm or more×728 mm or more; that a resolution of the transferred image is 2,400 dpi or more; that a stiffness in a machine direction (Msh) and a stiffness in a transverse direction (Tsh) of the thermal transfer sheet are both from 30 to 70 g; that a stiffness in a machine direction (Msr) and a stiffness in a transverse direction (Tsr) of the image receiving sheet are both from 40 to 90 g; that Msh/Tsh and Msr/Tsr are each from 0.75 to 1.20; and that 10 g≦(Msr−Msh)≦40 g and 10 g≦(Tsr−Tsh)≦40 g. 8. The multicolor image forming material according to claim 7, wherein the image forming layer of each of the thermal transfer sheets and the image receiving layer of the image receiving sheet each has a contact angle against water in a range of from 7.0 to 120.0°. 9. The multicolor image forming material according to claim 7 or 8, wherein the ratio OD/T of an optical density (OD) of the image forming layer of each of the thermal transfer sheets to a film thickness (unit: μm) of the image forming layer is 1.80 or more and that the contact angle of the image receiving sheet against water is not more than 86°. 10. A multicolor image forming material comprising an image receiving sheet containing an image receiving layer and thermal transfer sheets of different colors of 4 or more kinds of at least yellow, magenta, cyan and black, each containing a support and at least a photothermal converting layer and an image forming layer, wherein the image forming layer of each of the thermal transfer sheets and the image receiving layer of the image receiving sheet are superposed opposite to each other, and upon irradiation with laser beam, a laser beam irradiated region of the image forming layer is transferred onto the image receiving layer of the image receiving sheet to undergo multicolor image recording, therein a ratio OD/T of an optical density (OD) to a layer thickness (unit: μm) of the image forming layer of each of the thermal transfer sheets is 1.50 or more; that a recording area of multicolor image of each of the thermal transfer sheets is of a size of 515 mm or more×728 mm or more; that a resolution of the transferred image is 2,400 dpi or more; and that at least the magenta thermal transfer sheet has a breaking stress of from 150 to 300 MPa in both a machine direction (MD) and a crosswise direction (CD), with the breaking stress in the crosswise direction (CD) being at least 10 MPa larger than that in the machine direction (MD), and a breaking elongation of from 80 to 300% in both the machine direction (MD) and the crosswise direction (CD), with the breaking elongation in the machine direction (MD) being at least 5% larger than that in the crosswise direction (CD). 11. The multicolor image forming material according to claim 10, wherein the image forming layer of each of the thermal transfer sheets and the image receiving layer of the image receiving sheet each has a contact angle against water in the range of from 7.0 to 120.0°. 12. The multicolor image forming material according to claim 10 or 11, wherein the ratio OD/T of an optical density (OD) to a film thickness (unit: μm) of the image forming layer of each of the thermal transfer sheets is 1.80 or more and that the contact angle of the image receiving layer of the image receiving sheet against water is not more than 86°. 13. A multicolor image forming method including using a multicolor image forming material comprising an image receiving sheet containing an image receiving layer and thermal transfer sheets of different colors of 4 or more kinds, each containing a support and at least a photothermal converting layer and an image forming layer, superposing the image forming layer of each of the thermal transfer sheets and the image receiving layer of the image receiving sheet opposite to each other, and irradiating laser beam to transfer a laser beam irradiated region of the image forming layer onto the image receiving layer of the image receiving sheet, thereby undergoing multicolor image recording, wherein the multicolor image forming material is the multicolor image forming material according to any one of claims 1 to 12."
  ],
  "cpc": [
    "B41M 5/42",
    "B41M 5/345",
    "B41M 5/38207",
    "B41M 5/41",
    "B41M 5/52",
    "Y10S 430/14"
  ],
  "filing_date": "2002-12-17",
  "publication_date": "2005-05-26",
  "priority_date": "2001-12-17",
  "application_number": "US-49912704-A",
  "family_id": "27482737",
  "citations": [
    "US5252533A",
    "US6027850A",
    "US6326121B1",
    "US6790492B2",
    "US6830863B2",
    "US6864033B2"
  ]
}