Radiation imagery chemistry: process – composition – or product th – Radiation sensitive product – Silver compound sensitizer containing
Reexamination Certificate
2000-07-28
2001-08-28
Le, Hoa Van (Department: 1752)
Radiation imagery chemistry: process, composition, or product th
Radiation sensitive product
Silver compound sensitizer containing
Reexamination Certificate
active
06280920
ABSTRACT:
CROSS-REFERENCE TO RELATED APPLICATIONS
This application is based upon and claims the benefit of priority from the prior Japanese Patent Applications No. 11-216972, filed Jul. 30, 1999; No. 11-230895, filed Aug. 17, 1999; No. 11-246491, filed Aug. 31, 1999; and No. 2000-193162, filed Jun. 27, 2000, the entire contents of which are incorporated herein by reference.
BACKGROUND OF THE INVENTION
The present invention relates to a silver halide emulsion having a high sensitivity and an improved pressure property, and a silver halide photographic material using the same.
Manufacturing methods and use techniques of tabular silver halide grains are disclosed in U.S. Pat. Nos. 4,434,226, 4,439,520, 4,414,310, 4,433,048, 4,414,306, and 4,459,353. Known advantages of tabular grains are, e.g., improvements of the sensitivity/graininess relationship, including improvements of the color sensitization efficiency obtained by spectral sensitizing dyes.
Various studies have been made to improve the properties of tabular grains having such advantages.
U.S. Pat. No. 5,219,720 has disclosed a technique of improving the sensitivity/graininess ratio by decreasing the distance between twin planes of a tabular grain having (111) faces as major surfaces.
Jpn. Pat. Appln. KOKAI Publication No. (hereafter referred to as JP-A-)6-273869 has disclosed a technique of improving the manufacturing stability by using low-molecular-weight gelatin in a nucleation step in the formation of tabular grains.
On the other hand, demands for resistance to pressure of a silver halide emulsion is becoming stronger than before as the silver halide emulsion becomes to have a higher sensitivity. Generally, it is known that as various pressures are imposed to a silver halide photosensitive material, the photographic property thereof changes. For example, when a pressure is imposed to a silver halide photosensitive material during the manufacture thereof or during conveyance thereof in a camera, or the photographic material is bended, fogging arises or sensitivity decreases, which is a problem of a practical use. Especially, when a photosensitive material is bended, the bigger the equivalent-circle diameter and thinner the thickness of a tabular grain, the easier to occur fogging and reduced sensitivity. Accordingly, it was desired for such grains to both heighten the sensitivity and improve the pressure resistance.
Techniques to introduce dislocation lines with high density and to limit the position of the dislocation lines, and making distribution of silver iodide content between grains uniformly, are disclosed, for example, JP-A-6-27564 and JP-6-258745. Further, a technique to control the (100) surface area ratio to all the surface area of a tabular grain is disclosed, for example, in JP-A's-2-298935 and 8-334850.
However, there is no description in these patent applications of the use of an emulsion containing grains having a large equivalent-circle diameter and a thinner grain thickness, having a high (100) surface ratio to all the surface areas, and having high density dislocation lines introduced at a fringe portion of the grains, and in addition, the distribution of the silver iodide content between the grains is uniform.
Also, JP-A-8-95181 has disclosed a technique of increasing the sensitivity in a small-size region. However, a technique of increasing the sensitivity of tabular silver halide grains in a large-size region, which aims to achieve high sensitivity that is important in the competition with digital cameras in the future, is still immature. Hence, a technique of increasing the sensitivity has been desired.
BRIEF SUMMARY OF THE INVENTION
It is an object of the present invention to provide a silver halide photographic emulsion containing tabular grains in a large-size region, having high photographic sensitivity, and having a greatly improved resistance to pressure, and a silver halide photosensitive material using the same.
DETAILED DESCRIPTION OF THE INVENTION
The object of the present invention is achieved by a silver halide photographic emulsion and a silver halide photosensitive material using the same, described in Embodiment 1 to Embodiment 20 below:
(Embodiment 1) A silver halide photographic emulsion containing grains wherein a variation coefficient of distribution of an equivalent-circle diameter of all the grains is 40% or less, and 50% or more in number of all the grains satisfy requirements
(i) to (iii) below:
(i) silver iodobromide or silver bromochloroiodide tabular grains having (111) faces as major surfaces,
(ii) the equivalent-circle diameter is 3.5 &mgr;m or more and a thickness is 0.25 &mgr;m or less, and
(iii) a distance between twin planes of the tabular grain is 0.016 &mgr;m or less;
(Embodiment 2) The emulsion described in Embodiment 1, wherein a variation coefficient of distribution of the thickness of all the grains is 40% or less, and a variation coefficient of distribution of the distance between twin planes of all the grains is 40% or less;
(Embodiment 3) The emulsion described in Embodiment 1, wherein the tabular grains further satisfy, in addition to the requirements (i) to (iii), requirements (iv) and (v) below:
(iv) a silver iodide content is in a range from 0.7 I to 1.3 I, wherein I represents a specific silver iodide content (mol %) and 0.3<I<20, and
(v) ten or more dislocation lines per grain are present at a fringe portion;
(Embodiment 4) The emulsion described in Embodiment 3, wherein the range of the requirement (iv) is 0.8 I to 1.2 I;
(Embodiment 5) The emulsion described in Embodiment 3, wherein the tabular grains further satisfies, in addition to requirements (i) to (v), requirements (vi) below:
(vi) the dislocation lines are substantially localized only at a fringe portion of the grain;
(Embodiment 6) The emulsion described in Embodiment 5, wherein the tabular grains further satisfies, in addition to the requirements (i) to (vi), requirement (vii) below:
(vii) an electron-capturing zone is present;
(Embodiment 7) The emulsion described in Embodiment 6, wherein an average surface iodide content of all the grains is 5 mol % or less;
(Embodiment 8) The emulsion described in Embodiments 6 or 7, wherein the tabular grains have 10 or more dislocation lines, each having a length of 0.05 D or more, per grain, wherein D represents the equivalent-circle diameter;
(Embodiment 9) The emulsion described in Embodiment 1, wherein a coefficient of distribution of the distance between twin planes of all the grains is 40% or less, and the emulsion was prepared by using a low molecular, oxidated gelatin during a step of nucleation;
(Embodiment 10) The emulsion described in Embodiment 3, wherein the emulsion further satisfy requirement (viii) below:
(viii) an average value of long edge/short edge ratios of all the grains is 1.4 or less;
(Embodiment 11) The emulsion described in Embodiment 3, wherein the number of the dislocation lines of the requirement (v) is 30 or more per grain, and 80% or more in number of all the grains are occupied by tabular grains having dislocation lines substantially localized only at a fringe portion thereof, and a ratio of (100) surface area to the side surface area is 40% or more;
(Embodiment 12) The emulsion described in Embodiment 3, wherein the tabular gains further satisfies, in addition to the requirements (i) to (v), requirement (ix) below:
(ix) an average silver iodide content of the fringe portion is higher by 2 mol % or more than an average silver iodide content of the central portion;
(Embodiment 13) The emulsion described in any one of Embodiments 1 to 12, wherein the emulsion was prepared by using at least three kinds of gelatin at a time of grain formation;
(Embodiment 14) The emulsion described in any one of Embodiments 1 to 13, wherein the emulsion was prepared by adding a crystal habit-controlling agent during grain formation;
(Embodiment 15) The emulsion described in any one of Embodiments 1 to 14, wherein the coefficient of distribution of the equivalent-circle diameter of all the grains is 25% or less;
(Embodiment 16) The emulsi
Kikuchi Makoto
Maruyama Yoichi
Miki Masaaki
Sato Tadanobu
Birch & Stewart Kolasch & Birch, LLP
Fuji Photo Film Co. , Ltd.
Le Hoa Van
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