1. Field of the Invention
The present invention relates to a technique to improve fastness of an image formed by an ink jet process in an ink-receiving layer having a porous structure.
2. Related Background Art
To obtain high quality print or image by ink jet recording, both of the ink composition and the recording medium have been improved. It is required for the formed image not only high image quality such as no bleeding and excellent color reproducibility, but also maintenance of the high image quality for a long period, that is, resistance to the deterioration caused by both solar and room light, and chemical substances in air such as nitrogen oxides, sulfur oxides, hydrogen sulfide, chlorine, ozone and ammonium. Physical strength is also required for the formed image, not to deteriorate the image quality with abrasion etc. during exhibition or storage in a photo album.
Ink jet-recording is a method that records letters and images by flying micro droplets of ink (recording liquid) by various action principles to attach them on a recording medium such as paper. This method has characteristics such as high speed-low noise operation, easy multicolor printing, flexibility in recording pattern, and no need of development. Thus, this method has been developing and spreading rapidly not only as printers but also as the output part of information instruments such as copiers, word processors, facsimiles, and plotters. Moreover, in recent years, high performance digital cameras, video cameras and scanners are being provided at a low price as well as personal computers, where ink-jet printers are getting used as a printer to output the information obtained by these instruments. On such a background, output of an image of quality as high as that of a silver salt photograph or multicolor print by a printing plate system is being required for the ink jet-recording system.
On the other hand, preservation properties comparable to a silver salt photograph are also getting required for images recorded by the ink-jet method. To improve preservation properties of the recorded image, ink compositions and recording media have been improved. Specifically, to improve light-fastness of the recorded image, Japanese Patent Publication No. 6-30951 discloses a recording medium containing a specific cationic compound, Japanese Patent Publication No. 4-28232 discloses a recording medium containing an amino alcohol as a light-fastness-improving agent, and Japanese Patent Publication No. 4-34512 and Japanese Patent Application Laid-Open No. 11-245504 disclose a recording medium containing a hindered amine compound as a light-fastness-improving agent. Japanese Patent Publication No. 8-13569 shows a relationship between ozone gas and color change (mainly black to brown) of the recorded image during indoor storage, disclosing that a silica-based pigment with suppressed surface activity is effective to prevent color change of images indoors.