Radiation imagery chemistry: process – composition – or product th – Imaging affecting physical property of radiation sensitive... – Radiation sensitive composition or product or process of making
Reexamination Certificate
1997-09-05
2001-07-17
Angebranndt, Martin (Department: 1756)
Radiation imagery chemistry: process, composition, or product th
Imaging affecting physical property of radiation sensitive...
Radiation sensitive composition or product or process of making
C430S945000, C430S200000, C430S201000, C524S716000
Reexamination Certificate
active
06261739
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a laser ablative recording material, and a laser ablative record of an image formed through imagewise heating of the laser ablative recording material.
2. Description of the Related Art
Recently, a thermal transfer system forming an image by imparting an electric signal to a thermal print head has become more popular. A method of forming an image by the use of a laser in place of the thermal print head was on the other hand developed, and is expected to become more popular along with the tendency toward a higher laser output.
A recording material for laser recording contains a material having a strong absorption in the laser wavelength region, and this absorbing material converts optical energy into thermal energy, and brings about effects similar to those available by the use of a thermal print head. Use of a laser, unlike the use of a thermal print head, permits heating without contact with a recording material, thus providing an advantage of the image surface free from flaws. Because of the possibility to stop down a laser beam, there is provided another advantage of improving image resolution.
A method for forming an image using a high-output laser known as the dye ablation has recently been developed. Japanese Unexamined Patent Publications Nos. 7-164,755, 7-149,063, and 7-149,065 (corresponding to U.S. Pat. Nos. 5,330,876, 5,401,618 and 5,459,017) disclose recording materials applicable in this method, and Japanese Unexamined Patent Publications Nos. 8-48,053 and 8-72,400 (corresponding to U.S. Pat. Nos. 5,521,629 and 5,574,493) disclose imaging apparatuses used in this method. Image recording based on the ablation method is accomplished by irradiating a laser from a dye layer side onto a recording material having a dye layer comprising an image dye, a material having absorption in the laser wavelength region (infrared-absorbing material) and a binder formed on a support. On the spot to which the laser beam has been irradiated, a sharp local change takes place in an image forming layer under the effect of energy from the laser, and this drives away the material from the layer. According to the aforesaid patent publications, this local change is not a perfectly physical change such as melting, evaporation or sublimation, but a kind of chemical change such as bond-breaking, and is believed to be a complete, not partial, removal of the image dye.
Usefulness of this dye ablation imaging method largely depends upon removal efficiency of the imaging dyes upon laser exposure. As a scale representing this efficiency, the minimum concentration value (Dmin) of the laser exposure portion is employed. A smaller value of Dmin is suggested to lead to a higher dye removing efficiency, and provision of a laser ablative recording material having a small Dmin is demanded for.
SUMMARY OF THE INVENTION
The present invention has an object to provide a laser ablative recording material having a small Dmin and a high removing efficiency of imaging dyes upon laser exposure. Another object of the invention is to provide a laser ablative recording material, of which Dmin is reduced without leading to a decrease in Dmax. Further another object of the invention is to provide a laser ablative recording material having a small Dmin, which permits easy handling upon manufacture and requires only a small consumption of an organic solvent. It is also an object of the present invention to provide a laser ablative recording material having a small Dmin, which ensures a high storage stability of an image formed through imagewise heating and easy handling with little image decoloration caused by, for example, finger prints, and the resultant image-formed laser ablative record. The other objects of the invention would be easily understood from the entire description of this specification by a person skilled in the art.
These objects are achieved by providing the present invention having the following contents.
The present invention provides a laser ablative recording material, having one or more layers including a coloring agent layer on a surface of a support, wherein at least one layer from among one or more layers including said coloring agent layer contains nitric acid ester of carboxyalkyl cellulose having a degree of nitric acid ester group substitution per glucose anhydride unit within a range of from 0.05 to 2.8, and wherein at least one layer from among one or more layers including said coloring agent layer contains a material having absorption in the laser wavelength region.
The present invention provides also a laser ablative image-formed record prepared by irradiating a laser onto the laser ablative recording material.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
Now, the configuration and some preferred embodiments of the laser ablative recording material and the image-formed laser ablative record of the present invention will be described in detail below.
The laser ablative recording material of the present invention has a configuration in which one or more layers including a coloring agent layer (hereinafter referred to as the “layers on the coloring agent layer side”) on a surface of a support. So far as the coloring agent layer is provided on a surface of the support, no other limitation is imposed on the layer configuration of the laser ablative recording material of the invention. Therefore, an intermediate layer may be provided between the coloring agent layer and the support. An overcoat layer may be provided on the coloring agent layer. Further, a primer layer may be provided for achieving a higher close contact between the intermediate layer and the support. The coloring agent layer, the intermediate layer, the overcoat layer and the primer layer may be single or multiple. One or more layers including a backcoat layer (hereinafter referred to as the “layers on the backcoat layer side”) may be provided on the surface of the support opposite to the coloring agent layer.
In the laser ablative recording material of the invention, one or more kinds of nitric acid ester of carboxyalkyl cellulose are contained in at least one of the layers on the coloring agent layer side.
A nitric acid ester of carboxyalkyl cellulose is defined as part of hydroxide groups present in carboxyalkyl cellulose converted into a nitric acid ester. In the present invention, the nitric acid ester used should have a degree of nitric acid ester group substitution per glucose anhydride residue within a range of from 0.05 to 2.8. A degree of nitric acid ester group substitution of under 0.05 is not desirable because of insufficient dispersibility and water resistance of a developer and a dye. A degree of nitric acid ester group substitution of over 2.8 is not desirable because of the necessity of increasing the consumption of an organic solvent to dissolve or disperse the same in a mixed solvent of water and an organic solvent. The degree of nitric acid ester group substitution should more preferably be within a range of from 0.2 to 2.2.
Since nitric acid ester of carboxyalkyl cellulose having a degree of nitric acid ester group substitution within a range of from 0.05 to 2.8 is used in the present invention, it is possible to largely reduce the consumption of an organic solvent during manufacture of the laser ablative recording material. With a conventional recording material using a binder soluble only in an organic solvent such as cellulose nitrate, it is impossible to inhibit the organic solvent consumption. The high inflammability poses another problem of difficult handling during the coating step. Use of the nitric acid ester of carboxyalkyl cellulose permits resolution of these problems and allows to cope even with environmental problems.
Nitric ester of carboxyalkyl cellulose used in the invention should preferably have a degree of carboxyalkyl ether group substitution per glucose anhydride residue of over 0.05, or particularly preferably, from 0.05 to 1.5. A low degree of carboxyalkylether group substitution leads to an insuffici
Ishihara Makoto
Ito Tadashi
Obayashi Tatsuhiko
Watanabe Katsuyuki
Angebranndt Martin
Fuji Photo Film Co. , Ltd.
Sughrue Mion Zinn Macpeak & Seas, PLLC
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