The present invention relates a process for ink jet printing on cloth using ultraviolet ray curable ink, more specifically a process for ink jet printing and a printing apparatus, by which an image, which is unblurred and has high optical density, can be obtained and design can be imparted to the printed matter obtained thereby.
In recent years, various types of printers for computer output are becoming widely used. Of these, an ink jet printer is excellent in silence, cost and image quality and particularly, can reproduce full color images in high quality. Because an ink jet printer has excellent properties that other types of printers lack, many studies are being conducted regarding the ink jet, printing method using paper as a recording medium.
Among the ink jet printing methods, the ink jet printing method using ultraviolet ray curable ink is attracting attention. According to this method, the ink can be cured by exposing ultraviolet rays immediately after the ink is discharged from the head. Therefore, there is the advantage that durability of the applied ink is excellent. However, after the ultraviolet ray curable ink is applied, some time passes until ultraviolet rays are exposed and as a result, even in the case that ultraviolet rays are immediately exposed, bleeding of the ink cannot be inhibited in some cases depending on the recording medium.
Consequently, the method of forming an ink-receiving layer to improve ink absorbency is being considered (see for example JP-A-59-190885 and JP-A-11-321083).
However, by forming an ink-receiving layer, another step is increased in the preparation process and the advantage of being able to prepare in a small lot in a short period of time is lost.
Also, when the contact angle of the recording medium surface to deionized water satisfies a specific condition and the volume of the applied ink and the volume of ink that the recording medium can absorb satisfy a specific relationship, an ink layer having favorable wettability can be obtained without forming the above ink-receiving layer and favorable ink jet printing becomes possible (see for example JP-A-2000-117960). However, this invention is directed to a film having favorable wet properties and bleeding cannot be completely prevented when the recording medium is changed to cloth.
Furthermore, disclosed is the method of forming an ink receiving layer by applying an ultraviolet ray curable composition and curing with ultraviolet rays and then applying the ink, using an ink jet printing apparatus having a composition in which a head for the liquid composition, an ultraviolet ray exposing means and an ink head are lined in this order along the traveling direction of the recording medium (see for example JP-A-8-150707). However, this invention is directed mainly to acrylic boards and not to cloth and therefore bleeding cannot be completely prevented when the recording medium is changed to cloth. Also, because dye ink or pigment ink is used in this ink jet printing method, a long period of time is necessary to dry and furthermore, because the ink jet printing apparatus does not have a heating means, viscosity of the ink is difficult to control. In addition, because the composition contains water and a volatile solvent, the composition may foam when cured by ultraviolet rays, impairing appearance and quickening deterioration of the cured substance.
On the other hand, sufficient studies regarding recording mediums have not been conducted. Particularly, with respect to cloth which is used in the present invention, bleeding and density when printing are problems due to the special properties of cloth and a method for solving the above problems has not yet been achieved in the prior art.