Radiation imagery chemistry: process – composition – or product th – Nonradiation sensitive image processing compositions or... – Developer
Reexamination Certificate
2000-07-21
2001-09-11
Le, Hoa Van (Department: 1752)
Radiation imagery chemistry: process, composition, or product th
Nonradiation sensitive image processing compositions or...
Developer
Reexamination Certificate
active
06287753
ABSTRACT:
CROSS-REFERENCE TO RELATED APPLICATIONS
This application is based upon and claims the benefit of priority from the prior Japanese Patent Applications No. 11-208021, filed Jul. 22, 1999; No. 11-218868, filed Aug. 2, 1999; No. 11-271280, filed Sep. 24, 1999; and No. 2000-145051, filed May 17, 2000, the entire contents of which are incorporated herein by reference.
BACKGROUND OF THE INVENTION
The present invention relates to a silver halide photographic emulsion used in a silver halide photosensitive material and, more particularly, to a high-speed silver halide photographic emulsion superior in development dependence.
It is well known to use tabular silver halide grains (to be referred to as “tabular grains” hereinafter) or to use large-size silver halide grains in order to obtain a high-speed silver halide photosensitive material. However, raising the sensitivity by increasing the size of tabular grains is difficult because the equivalent-circle diameter of the grains extremely increases compared to common silver halide grains. One possible reason is that photoelectrons cannot be concentrated to one location because their diffusion length extremely increases, so no latent images can be efficiently formed. To solve this problem, U.S. Pat. Nos. 5,612,175, 5,612,176, 5,612,177, and 5,614,359 have disclosed a sensitization method which uses an epitaxial junction of silver chloride to large-size tabular grains. Unfortunately, this method using a silver chloride epitaxial junction has the problem that unstable solubility of the epitaxial portion increases the KBr dependence during development. So, the method cannot be widely used for general sensitized materials.
U.S. Pat. No. 5,709,988 has disclosed a sensitization method by which dislocation lines are introduced to fringe portions of tabular grains more densely than dislocation lines introduced to major surfaces of the grains. However, this method does not show any solution to delay of development caused by the increased size of tabular grains, although the sensitivity can be raised to some extent. That is, the magnitude of the processing dependence when large-size tabular grains are used is still unsolved.
U.S. Pat. No. 5,780,216 has disclosed a technique to improve the sensitivity/graininess ratio by a tabular grain emulsion having a multilayered structure of quintuple or higher-order. Unfortunately, in this patent the shell silver iodide content is as high as 15 to 40 mol %. Hence, development delay during processing cannot be solved even when the method is applied to large-size tabular grains used in the present invention.
BRIEF SUMMARY OF THE INVENTION
It is an object of the present invention to provide a silver halide photographic emulsion capable of increasing the sensitivity of high-aspect-ratio, large-size tabular grains and at the same time solving the problem that the processing dependence such as development delay is large, and to provide a photosensitive material using the same.
The above object is achieved by means (1) to (15) below.
(1) A silver halide photographic emulsion, wherein the variation coefficient of equivalent-circle diameters of all grains is 40% or less, and 50% or more of the total projected area are accounted for by tabular grains meeting conditions (i) to (v) below:
(i) the tabular grains are silver iodobromide or silver bromochloroiodide tabular grains having (111) faces as major surfaces
(ii) an equivalent-circle diameter is 3.5 &mgr;m or more and a thickness is 0.25 &mgr;m or less
(iii) a silver iodide content is 2 to 6 mol %
(iv) a silver chloride content is 3 mol % or less
(v) a silver iodide distribution has a multilayered structure of quintuple or higher-order.
(2) A silver halide photographic emulsion described in item (1) above, wherein the silver iodide distribution has a multilayered structure of sextuple or higher-order.
(3) A silver halide photographic emulsion described in item (1) or (2) above, wherein when irradiated with an electromagnetic beam of 325 nm at 6 K, the emulsion generates induced fluorescence of 575 nm which is at least ⅓ the intensity of maximum fluorescence emission induced in a wavelength range of 490 to 560 nm.
(4) A silver halide photographic emulsion described in any one of items (1) to (3) above, wherein the average silver iodide content on the surfaces of all grains is 5 mol % or less.
(5) A silver halide photographic emulsion described in any one of items (1) to (4) above, wherein letting It be the average silver iodide content of a whole grain and Is be the average silver iodide content on the surface of the grain,
0.3•It≦Is
holds.
(6) A silver halide photographic emulsion described in any one of items (1) to (5) above, wherein at least a portion of the silver halide grain has a positive hole capturing zone.
(7) A silver halide photographic emulsion described in any one of items (1) to (6) above, wherein the tabular grains meeting the conditions (i) to (v) recited in (1) have dislocation lines localize in the vicinities of corners of the grains.
(8) A silver halide photographic emulsion described in any one of items (1) to (7) above, wherein the variation coefficient of equivalent-circle diameters of all grains is 25% or less.
(9) A silver halide photographic emulsion described in any one of items (1) to (8) above, wherein the condition (ii) recited in (1) is that the equivalent-circle diameter is 3.5 &mgr;m or more and the thickness is 0.15 &mgr;m or less.
(10) A silver halide photographic emulsion described in any one of items (1) to (8) above, wherein the condition (ii) recited in (1) is that the equivalent-circle diameter is 4.0 &mgr;m or more and the thickness is 0.15 &mgr;m or less.
(11) A silver halide photographic emulsion described in any one of items (1) to (8) above, wherein the condition (ii) recited in (1) is that the equivalent-circle diameter is 4.0 &mgr;m or more and the thickness is 0.10 &mgr;m or less.
(12) A silver halide photographic emulsion described in any one of items (1) to (11) above, wherein the emulsion is spectrally sensitized by a spectral sensitizing dye.
(13) A silver halide photographic emulsion described in any one of items (1) to (12) above, wherein the emulsion contains 400 to 2,500 ppm of calcium ions and/or 50 to 2,500 ppm of magnesium ions.
(14) A silver halide photographic emulsion described in any one of items (1) to (13) above, wherein the emulsion is selenium-sensitized and contains at least one type of a water-soluble mercaptotetrazole compound represented by formula (I-1) below and at least one type of a water-soluble mercaptotriazole compound represented by formula (I-2) below:
Formula (I-1)
wherein R
5
represents an organic residue substituted by at least one member selected from the group consisting of —SO
3
M, —COOM, —OH, and —NHR
2
, M represents a hydrogen atom, an alkali metal atom, a quaternary ammonium group, or a quaternary phosphonium group, R
2
represents a hydrogen atom, C
1
-C
6
alkyl, —COR
3
, —COOR
3
, or —SO
2
R
3
, and R
3
represents a hydrogen atom, alkyl, or aryl;
Formula (I-2)
wherein R
6
represents a hydrogen atom, substituted or nonsubstituted alkyl, or substituted or nonsubstituted aryl, R
5
represents an organic residue substituted by at least one member selected from the group consisting of —SO
3
M, —COOM, —OH, and —NHR
2
, M represents a hydrogen atom, an alkali metal atom, a quaternary ammonium group, or a quaternary phosphonium group, R
2
represents a hydrogen atom, C
1
-C
6
alkyl, —COR
3
, —COOR
3
, or —SO
2
R
3
, and R
3
represents a hydrogen atom, alkyl, or aryl.
(15) A silver halide photosensitive material comprising a sensitive layer containing a silver halide photographic emulsion described in any one of items (1) to (14) above on a support.
Additional objects and advantages of the invention will be set forth in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. The objects and advantages of the invention may be realized and obtained by means of the instrumentalities and combinat
Ihama Mikio
Kawakami Hiroshi
Nakatsugawa Haruyasu
Birch & Stewart Kolasch & Birch, LLP
Fuji Photo Film Co. , Ltd.
Le Hoa Van
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