1. Field of the Invention
The present invention relates to a method for producing a print.
2. Description of the Related Art
Images formed on objects such as printing paper, in particular, images formed by a sublimation thermal transfer process using a sublimation dye or a thermally diffusible dye, have been laminated with transparent films to protect the surfaces of the images.
The image protecting functions desired for the transparent films vary widely and include following: to block gas that causes image deterioration, to prevent changes in color of the images by imparting a ultraviolet (UV) absorbing function to the transparent films, to impart plasticizer resistance so that the dyes forming images are prevented from migrating into various plasticizer-containing articles such as erasers, to impart wear resistance, and to impart resistance to sebum.
There also exist various methods for lamination with transparent films.
Examples of such lamination methods include a method for thermocompressing a transparent film onto an image surface by using a hot roller and a method for bonding a transparent film on an image surface with an adhesive at room temperature.
Japanese Unexamined Patent Application Publication Nos. 60-204397, 59-85793, and 59-76298 describe a method for forming an image-protecting layer (i.e., transparent film) on an image, in which a transfer-type image-protecting film constituted by a base film and an image-protecting layer composed of a thermoplastic resin and disposed on the base film is prepared and the image-protecting layer of the transfer-type image-protecting film is thermally transferred onto the image to be protected so as to form the image-protecting layer.
According to the transfer-type image-protecting film described above, only the portion of the image-protecting layer that has been heated during thermal transfer is laminated on the image to be protected. Thus, curling of the printing paper after lamination can be suppressed.
Moreover, it is also possible to form the image-protecting layer in an ink ribbon used for image formation so that the image-protecting layer can be laminated continuously after image formation in a printer.
Japanese Unexamined Patent Application Publication Nos. 61-197282 and 62-198497 propose a supporting member in which a plastic film is bonded to a core material layer such as paper and a supporting member in which a biaxially stretched film (synthetic paper) including voids (gaps) mainly composed of a thermoplastic resin such as polyolefin resin is bonded to a core material layer such as paper.
However, although image-receiving sheets incorporating these supporting members have good heat insulation and flat/smoothness, they lack paper-like texture and are costly.
In the cases where a paper sheet is used as the supporting base of the image-receiving sheet, the cushioning property is slightly improved from when a film is used as the base although the sensitivity is insufficient as with the case of using a film. However, nonuniformity in density of paper fibers causes nonuniformity in adhesion between an ink ribbon and the image-receiving layer, and this causes nonuniformity in density of the printed image.
In order to overcome these inconveniences, Japanese Unexamined Patent Application Publication Nos. 64-27996 and 63-87286 provide an image-receiving sheet in which an intermediate layer containing hollow particles is interposed between a sheet-shaped supporting member made of paper or the like and an image-receiving layer.
Of these, an image-receiving sheet that uses a supporting film system in which a plastic film is bonded to a core material layer such as paper has good heat insulation and flat/smoothness. However, heat and pressure applied during sheet-conveying and image-printing in a printer create dents in the image-receiving sheet, thereby impairing the appearance.
Another problem is the high cost of the foamed film. In order to control the thickness of the whole image-receiving sheet to a predetermined thickness, a thick foamed film is desirably used, but this is economically disadvantageous. Also, the texture of the resulting image-receiving sheet is different from that of printing paper used for silver halide photos.
An example of technique for processing an image surface of printing paper into a desired pattern such as a matt pattern is to use a transfer-type laminate film. For example, the transfer-type laminate film may be constituted by a base member having a matt-finished surface and a protective layer (laminate layer) formed on the matt-finished base member by application.
For example, such a transfer-type laminate film may be used by superimposing the transfer-type laminate film on an image surface (surface on which the image is formed) of a printing paper (in the case where the image is formed by dye sublimation thermal transfer, the transfer-type laminate film is formed on a dye image-receiving layer), thermally compressing the laminate film onto the printing paper, and then detaching the base member.
In this manner, the surface asperity of the base member is transferred onto the surface of the protective layer transferred onto the printing paper. Thus, the image surface of the printing paper is imparted a matt texture.
However, in the case where a transfer-type laminate film is used to impart a desired pattern to the surface of a transparent film laminated on the image surface of the printing paper, the desired pattern is desirably preliminarily formed on the surface of the base member during production of the transfer-type laminate film. This increases the production cost.
In recent years, a technique that can easily improve and modify the tone of a print has been developed (for example, refer to Japanese Unexamined Patent Application Publication No. 7-52428 and World Patent Application (PCT) Publication WO97/039898 (transfer originating from Japan). According to this technique, in thermally transferring, with a thermal head, an image-protecting layer onto an image recording surface after formation of the image, thermal energy from the thermal head is adequately changed so as to form the protective layer and impart a desired texture (silk-, matt-, or gloss-finish, for example) to the surface of the protective layer simultaneously.
However, it has been found that this method faces following challenges during forming an image on a base sheet and during laminating an image-protecting layer and simultaneously patterning the surface.
The challenges that exist during formation of images on the base member sheet are as follows.
In the cases where an image-receiving sheet uses a supporting base/film system in which a plastic film is bonded to a core material layer such as paper, the texture of the resulting print is different from that of printing paper for silver halide photos. The image-receiving sheet incorporating the supporting base/film system is usually disadvantageous in terms of cost.
Thus, in order to obtain a print that has a texture similar to that of the silver halide photos and is advantageous in terms of cost, a supporting member prepared by sequentially laminating a hollow particle-containing layer and an image-receiving layer on a paper supporting base is used. Compared to the cases where the supporting base is constituted by a film, the texture of the print is improved and the resulting print has a texture similar to that of silver halide photos.
However, when high thermal energy is applied in laminating the image-protecting layer, the intermediate layer containing the hollow particles thermally swell in the region where the heat is applied, a desired clear glossiness difference pattern is rarely obtained, and the quality of the print may be degraded.
In recent years, in order to comply with high speed printing, a recording method with a higher conveying rate per line is being developed.
In such a case, in order to shorten the time for forming images and time for forming the image-protecting layer, the conveying rate during image formation and the conveying rate during image-protecting layer formation are increased as much as possible.
In the cases where the image-forming layer is formed at an ever higher conveying rate, the pattern that creates differences in surface glossiness and that is formed during the image-protecting layer transfer becomes less clear compared to the case where the conveying rate of the image-receiving sheet is not as high.