1. Field of the Invention
This invention relates to an image forming method using ink such as image formation with a felt pen, a fountain pen, a pen plotter, an ink jet recording device, etc., particularly an image forming method for obtaining a recorded image of high image quality excellent in light transmittance or gloss, and also excellent in color characteristic, resolution, water resistance, light resistance, storability, etc.
2. Description of the Related Art
Heretofore, the image forming method using ink may include, for example, writing with a fountain pen, a felt pen, a ball pen, etc., and an image forming method by a pen plotter, an ink jet recording device, etc., and the recording medium for these image forming methods may include general paper such as pure paper, bond paper, writing paper, etc., or coated paper such as art paper, cast-coated paper, etc.
On the other hand, as the ink used for the image forming method as mentioned above, aqueous ink is primarily used, and in forming a multi-color image, at least three kinds of aqueous inks of cyan, magenta and yellow have been used in most cases.
However, in recent years, with development of recording instruments such as ink jet recording devices, pen plotters, etc., satisfactory recording characteristic cannot be obtained with the recording medium of the prior art as mentioned above.
Recent image forming methods as mentioned above conduct higher speed recording and multi-color recording which could not be practiced in the past. Accordingly, with the recording medium of the prior art, absorptivity of ink, color forming characteristic with plural inks applied on the same spot, color characteristic, etc. have not reached satisfactory levels yet.
For solving these problems, a kind of coated paper comprising a porous ink absorbing layer on the substrate surface as typified by ink-jet recording paper has been developed. For example, Japanese Laid-open Patent Publication No. 214989/1985 discloses a sheet comprising a porous ink-absorbing resin layer provided on a substrate.
This ink-absorbing layer is porous and includes fine pores or cracks therein, which accelerate ink absorption.
Although a porous ink absorbing layer can enhance ink absorption to some extent, the recording medium has light diffusivity owing to the porocity of the absorbing layer, thereby giving, no clear recorded image with high optical density or recorded image with gloss.
For observation of the recorded ink image from the recorded side, there is adopted the constitution of the medium which permits the recording agent (dye or pigment, hereinafter simply called dye) to remain on the surface of the absorbing layer as much as possible, which leads to the drawback that the image is inferior in durability such as in water resistance, frictional resistance and storability.
As a method for solving such problems, Japanese Laid-open Patent Publication No. 27426/1978, for example, discloses a recording material with a recording layer formed by fixing thermoplastic resin particles on the surface of a sheet substrate and baking thermally the recording layer after recording to give the surface gloss and also enhance frictional resistance, water resistance, light resistance, storability, etc. This recording material can solve most of the drawbacks as mentioned above, but in the method using this recording material, the image is liable to be disturbed to lose its fineness especially in fine images because the image is formed in the recording medium which is later softened or melted on the subsequent heating treatment. Japanese Laid-open Patent Publication No. 77154/1981 discloses a method in which recording is effected on a recording sheet having a porous structure as described above and then the voids of the porous structure are filled with another material. This method can solve various drawbacks as mentioned above, but because a liquid material such as a resin solution, etc., is used as a filler, another drawback arises that the operations are cumbersome. Moreover, since the image is formed in the porous layer to which the liquid material is directly applied, the dye forming an image may be dissolved, feathered or flowed to cause disturbance of the image, ensuing the problem that fineness is impaired in the case of a fine image formation as described above.
Therefore, an image forming method is desired which is free from such problems yet exhibits excellent ink absorption ability, water resistance, anti-blocking property, etc., during recording and which can provide invariably images having excellent quality such as light transmittance or gloss, color characteristic, high image density, resolution, water resistance, light resistance, storability, etc.
Nevertheless, no image forming method having all of these recording characteristics at the same time has been obtained yet.