Ink jet recording apparatus, ink-jet recording method and ink jet recording medium

1. An ink jet recording method comprising the steps of:

forming an image on a recording medium comprising a support having thereon an ink absorptive layer comprising an inorganic pigment and a water soluble binder by jetting an ink onto the recording medium; and

correcting a curl of the recording medium by applying heat and pressure to the recording medium,

wherein the recording medium shows a curl value of between −10 and 10 mm after applying a heat and pressure treatment in the following condition to the recording medium having a curl value between −30 of −40 mm,

wherein the condition of the heat and pressure treatment is:

employing an apparatus comprising a φ30 mm circular iron cylinder having a heater in its interior as an upper roller and a φ30 mm silicone rubber roller as a lower roller, both of which are covered with a tetrafluoroethylene-perfluoroalkyl ether copolymer having a thickness of 100 μm;

feeding the recording medium in so that the upper roller comes into contact with the surface of the ink absorptive layer; and

subjecting the recording medium to the heat and pressure treatment under conditions of a nip width of 0.3 mm, a linear pressure of 32 kgf/297 mm, transporting rate of 10 mm/second and the surface temperature of the upper roller of 120° C.

2. The ink jet recording method of claim 1 , wherein the weight ratio of the inorganic pigment to the water soluble binder in the ink absorptive layer of the recording medium is from 3:1 to 9:1.

3. The ink jet recording method of claim 1 , wherein the ink absorptive layer of the recording medium comprises an emulsion resin having a glass transition point Tg of not more than 20° C., and the emulsion resin is obtained with utilizing polyvinyl alcohol as a dispersing medium.

4. The ink jet recording method of claim 1 , wherein the recording medium further comprising a surface layer comprising a thermoplastic resin on the ink absorptive layer.

5. The ink jet recording method of claim 4 , wherein the surface layer further comprises a inorganic pigment.

6. The ink jet recording method of claim 4 , wherein the heat applied to the recording medium in the correcting step is lower than the melt temperature of the thermoplastic resin.

7. The ink jet recording method of claim 1 , wherein the center line mean roughness specified in JIS B 0601 of the ink absorptive layer is 0.8 to 4.0 when the ink absorptive layer is measured at a standard length of 2.5 mm and a cut-off value of 0.8 mm.

8. The ink jet recording method of claim 1 , wherein the ink is a pigment ink.

9. An ink jet recording medium comprising a support having thereon an ink absorptive layer comprising an inorganic pigment and a water soluble binder and a surface layer comprising a thermoplastic resins,

wherein the recording medium shows a curl value of between −10 and 10 mm after applying a heat and pressure treatment of the following condition to the recording medium having a curl value between −30 to −40 mm,

wherein the condition of the heat and pressure treatment is:

employing an apparatus comprising a φ30 mm circular iron cylinder having a heater in its interior as an upper roller and a φ30 mm silicone rubber roller as a lower roller, both of which are covered with a tetrafluoroethylene-perfluoroalkyl ether copolymer having a thickness of 100 μm;

feeding the recording medium in so that the upper roller come into contact with the surface of the ink absorptive layer; and

subjecting the recording medium to the heat and pressure treatment under conditions of a nip width of 0.3 mm, a linear pressure of 32 kgf/297 mm, transporting rate of 10 mm/second and the surface temperature of the upper roller of 120° C.

10. The ink jet recording medium of claim 9 , wherein the surface layer further comprises an inorganic pigment.