EP0361948A1

EP0361948A1 - Method of preparing silver halide photographic paper

Info

Publication number: EP0361948A1
Application number: EP89309954A
Authority: EP
Inventors: Atsuo Ezaki; Hiroshi Kashiwagi; Masaru Iwagaki
Original assignee: Konica Minolta Inc
Current assignee: Konica Minolta Inc
Priority date: 1988-09-30
Filing date: 1989-09-29
Publication date: 1990-04-04
Also published as: JPH0293640A

Abstract

A silver halide photographic paper, comprising a paper support coated on both sides with a polyolefin, and, provided thereon, light-sensitive layers comprising a red-sensitive silver halide emulsion layer, a green-sensitive silver halide emulsion layer, and a blue-sensitive silver halide emulsion layer, in this sequence from the support, wherein:
the support has an average center surface roughness of not more than 1.0 µm; and
the light-sensitive layers have been obtained by coating solutions thereof on the support at a speed of not slower than 60 meter/minute.

Description

FIELD OF THE INVENTION

The present invention relates to a silver halide photographic paper. More particularly, it relates to a silver halide photographic paper that is more free from coating mottles on light-sensitive emulsion layers and promises a high productivity.

BACKGROUND OF THE INVENTION

Silver halide photographic papers commonly comprise a support and a photographic light-sensitive layer provided thereon. There have been hitherto known photographic papers in which a baryta paper is used as the support and a light-sensitive emulsion is coated thereon. Also known are photographic papers in which a light-sensitive emulsion is coated on a water-resistant support coated with polyethylene on its both sides. Recently, however, the photographic papers using the polyethylene-coated paper as a support have been prevailingly on the market for the reasons that they are suited for rapid processing and require no ferrotype finishing in a drying step.
In preparing such photographic papers using the polyethylene-coated paper as a support, ununiform coating called "mottle" is liable to often occur when an emulsion is coated to bring about a problem on quality.
As means for solving the above problem arising when the polyethylene-coated paper is used, Japanese Patent Publication Open to Public Inspection (hereinafter referred to as Japanese Patent O.P.I. Publication) No. 37642/1983, discloses a support for photographic papers, in which there is coated polypropylene on both sides of a paper having a surface smoothness of 95 seconds or more measured with a Beck's smoothness meter. Japanese Patent O.P.I. Publication No. 68037/1983 also discloses a support for photographic papers, in which there is coated polyethylene on both sides of a paper comprising pulp fiber with a residue of not less than 20% by weight and not more than 45% by weight on a 42 mesh screen in a fiber length distribution measured with a fiber classifier.
Both of these, however, merely teach a smoothness itself of a support on a correlation with gloss, and it is still sought to improve the support itself.
Usually, in color photographic papers, a color-forming layer adjacent to the support is a yellow color-forming layer in a conventional negative photographic paper, while it is a cyan color-forming layer in a positive photographic paper. This is liable to make the coating mottles more conspicuous in the positive type than in the negative type.
An attempt to avoid such mottles by improving a mechanical coating means in a manufacturing process rather than the support itself in turn may bring about another problem of lowered productivity.

SUMMARY OF THE INVENTION

An object of the present invention is to provide a preparation method in which a photographic paper can be prepared at a high level of productivity with the improved coating mottles, even in the positive color papers that require severe quality for the coating mottles.
The above object of the present invention can be achieved by a method of preparing a silver halide photographic paper comprising a photographic paper support coated on the both sides thereof with polyolefine, and the photographic component layers including the photographic light-sensitive layers, said method comprising the steps of: providing on the support, a red-sensitive silver halide emulsion layer, a green-sensitive silver halide emulsion layer, and a blue-sensitive silver halide emulsion layer in this sequence therefrom, said support having an average surface center roughness of not more than 1.0 µm calculated from the following equation:
SRa = 1/S_A∫_O ^WX∫_O ^WY|f(x,y|dxdy
wherein W_X represents a length in an X-axis direction of a measured surface region; W_Y represents a length in a Y-axis direction of the measured surface region; S_A represents an area of the measured surface region; S_A =W_X x W_Y, W_X = W_Y = 5 mm, and S_A = 25 mm²; and,
coating the photographic component layers on the support at a speed of not slower than 60 meter/minute.

DETAILED DESCRIPTION OF THE INVENTION

In the present invention, the above average center surface roughness (SRa) can be determined using a surface roughness analyzer SE-3AK, manufactured by Kosaka Laboratory.
The support used in the present invention comprises a paper provided on its both sides with polyolefine coatings. An example thereof is a polyethylene-coated paper, but other polyolefine-coated papers can be also used.
The above polyolefine-coated papers used in the present invention such as the polyethylene-coated paper can be commonly prepared by a method in which polyethylene melted at a high temperature is coated on the surface of a travelling paper.
In the present invention, the light-sensitive silver halide emulsion layers comprising a red-sensitive layer, a green-sensitive layer and a blue-sensitive layer are provided in this order from the support side. The respective light-sensitive layers may be constituted of a single layer or plural layers such as dual layers consisting of a high-sensitivity layer and a low-sensitivity layer. They may be divided into further more layers. An intermediate layer may be provided between the respective layers.
In the present invention, the silver halide light-sensitive photographic layers are provided at a coating speed of not slower than 60 m/min, and such coating speed can increase the productivity. In the prior art, however, such a high speed used to form the coating mottles. More specifically, in the case of SRa more than 1.0 µm, a higher coating speed results in forming more coating mottles. The lower coating speed is liable to result in improving the coating mottles, while it deteriorates the productivity. The present invention has settled such problems.
Coating solutions used for providing the layers in the present invention may have any viscosity. A solution for coating at least one layer of the first to fifth photographic component layers provided on the support, however, has preferably a viscosity of 15 cps to 60 cps.
A silver halide emulsion used for the photographic paper in the present invention may be of any composition, but a silver bromoiodide emulsion is preferred.
The emulsions can be chemically sensitized according to a conventional method, and also can be spectrally sensitized to any desired wavelength regions with sensitizing dyes.
To the silver halide emulsions, antifoggants and stabilizer may be added. As a binder for the emulsions, gelatin is preferably used.
The emulsion layers and the other hydrophilic colloid layers may be hardened. There may also be incorporated plasticizers and water-insoluble or slightly soluble synthetic polymer latexes.
The photographic paper of the present invention has the red, green and blue light-sensitive layers, each containing conventional couplers.
It is also possible to further use competing couplers used for color correction, and the compounds capable of releasing photographically useful fragments such as development accelerators, bleach accelerators, developers, silver halide solvents, toning agents, hardening agents, fogging agents, antifoggants, chemical sensitizers, spectral sensitizers, and desensitizers by coupling with the oxidation products of developing agents.
The photographic paper can be also provided with auxiliary layers such as an intermediate layer, an anti-halation layer, a UV absorbing layer, and a protective layer.
There may be incorporated into the photographic paper, formalin scavengers, brightening agents, matting agents, lubricants, image stabilizers, surface active agents, anti-color-fogging agents, development accelerators, development restrainers, and bleach accelerators.
To form a dye image on the photographic paper of the present invention, a conventional color photographic processing may be carried out after exposure.

EXAMPLES

The present invention will be described below in more details by demonstrating Examples. The present invention, however, is by no means limited thereto.

Example 1

On a paper support (average center surface roughness SRa: 2.0 µm) coated with polyethylene on both sides, the following first to eleventh layers were provided to prepare a color reversal light-sensitive material Sample 1. The coated amount for each component is indicated in terms of g/m². Those of silver halides are indicated in an amount converted to silver.

First layer (Anti-halation layer):
Black colloidal silver	0.10
Gelatin	1.5

Second layer (First red-sensitive layer):
Cyan coupler C-1	0.080
Cyan coupler C-2	0.16
Anti-fading agent A-1	0.12
Anti-fading agent A-2	0.06
High-boiling solvent O-1	0.18

Emulsion containing AgBrI grains (AgI: 6.0 mol %; average grain size: 0.4 µ) spectrally sensitized by red sensitizing dyes S-1, S-2
0.14
Gelatin	0.81

Third layer (Second red-sensitive layer):
Cyan coupler C-1	0.043
Cyan coupler C-2	0.085
Anti-fading agent A-1	0.064
Anti-fading agent A-2	0.032
High-boiling solvent O-1	0.097

Emulsion containing AgBrI grains (AgI: 6.0 mol %; average grain size: 0.8 µ) spectrally sensitized by red sensitizing dyes S-1, S-2
0.16
Gelatin	0.98

Fourth layer (First intermediate layer):
Anti-stain agent AN-1	0.020
Anti-stain agent AN-2	0.060
High-boiling solvent O-2	0.13
Gelatin	0.90

Fifth layer (First green-sensitive layer):
Magenta coupler C-3	0.25
Anti-fading agent A-3	0.067
Anti-fading agent A-4	0.12
High-boiling solvent O-1	0.19

Emulsion containing AgBrI grains (AgI: 6.0 mol %; average grain size: 0.4 µ) spectrally sensitized by a green sensitizing dye S-3
0.15
Gelatin	0.93

Sixth layer (Second green-sensitive layer):
Magenta coupler C-3	0.15
Anti-fading agent A-3	0.040
Anti-fading agent A-4	0.070
High-boiling solvent O-1	0.11

Emulsion containing AgBrI grains (AgI: 6.0 mol %; average grain size: 0.7 µ) spectrally sensitized by a green sensitizing dye S-3
0.15
Gelatin	0.83

Seventh layer (Second intermediate layer):
Yellow colloidal silver	0.02
Anti-stain agent AN-1	0.014
Anti-stain agent AN-2	0.046
High-boiling solvent O-1	0.096
Gelatin	0.90

Eighth layer (First blue-sensitive layer):
Yellow coupler C-4	0.24
Anti-fading agent A-1	0.096
Anti-fading agent A-5	0.048
High-boiling solvent O-3	0.048

Emulsion containing AgBrI grains (AgI: 6.0 mol %; average grain size: 0.4 µ) spectrally sensitized by a blue sensitizing dye S-4
0.15
Gelatin	0.95

Ninth layer (Second blue-sensitive layer):
Yellow coupler C-4	0.32
Anti-fading agent A-1	0.13
Anti-fading agent A-5	0.064
High-boiling solvent O-3	0.064

Emulsion containing AgBrI grains (AgI: 6.0 mol%; average grain size: 0.8 µ) spectrally sensitized by a blue sensitizing dye S-4	0.13
Gelatin	0.93

Tenth layer (UV absorbing layer):
UV absorbent U-1	0.45
UV absorbent U-2	0.15
Anti-stain agent AN-1	0.033
High-boiling solvent O-3	0.037
Gelatin	1.87

Eleventh layer (Protective layer):
Gelatin	0.50

In addition to the above, a hardening agent and an anti-irradiation dye are contained.
The silver halide emulsions used in the respective light-sensitive layers were prepared according to the method disclosed in Japanese Patent O.P.I. Publication No. 178447/1984. The emulsions were subjected to desalting and washing with water, followed by optimal chemical ripening in the presence of sodium thiosulfate, chloroauric acid and ammonium thiocyante, and further chemical ripening by addition of sensitizing dyes 4-hydroxy-6-methyl-1, 3, 3a, 7-tetrazaindene and 1-phenyl-5-mercaptotetrazole.
The viscosity values of the first and second layers, and the coating speed in providing the above silver halide emulsion layers are shown in Table 1.
In the same procedure as the above Sample 1, Samples 2 to 7 were prepared. The average center surface roughness (SRa) values, coating speed, and viscosity values of the first and second layers are similarly shown in Table 1. The SRa values are indicated by the values measured with the surface roughness analyzer SE-3AK manufactured by Kosaka Laboratory. In each sample, a multi-layer coater of a multi-slide hopper type was used to carry out simultaneous multi-layer coating.

Next, each sample was exposed to light of a wavelength region sensitive to the cyan couplers in such exposure that a density of a cyan-dye image ranges from 0.80 to 0.90. The processing was carried out as follows:

First developing (monochromatic development)	1 min 15 sec (38°C)
Washing	1 min 30 sec
Light fogging,more than 100 lux	1 sec or more
Second developing (color development)	2 min 15 sec (38°C)
Washing	45 sec
Bleach-fixing	2 min (38°C)
Washing	2 min 15 sec

First development solution
Potassium sulfite	3.0 g
Sodium thiocyanate	1.0 g
Sodium bromide	2.4 g
Potassium iodide	8.0 mg
Potassium hydroxide (48% solution)	6.2 mℓ
Potassium carbonate	14 g
Sodium hydrogencarbonate	12 g
1-Phenyl-4-methyl-4-hydroxymethyl-3-pyrazolidone	1.5 g
Hydroquinone monosulfonate	23.3 g
Water was added to	1.0 ℓ
pH was adjusted to	9.65

Color developing solution
Benzyl alcohol	14.6 mℓ
Ethylene glycol	12.6 mℓ
Potassium carbonate (anhydrous)	26 g
Sodium hydroxide	1.4 g
Sodium sulfite	1.6 g
3,6-dithiaoctane-1,8-diol	0.24 g
Hydroxylamine sulfate	2.6 g

4-N-ethyl-N-β-(methanesulfonamidoethyl)-2-methyl-p-phenylenediamine sesquisulfate	5.0 g
Water was added to	1.0 ℓ

Bleach-fixing solution
Ammonium ferric ethylenediaminetetraacetate (1.56 mol solution)	115 mℓ
Sodium metabisulfite	15.4 g
Ammonium thiosulfate (58% solution)	126 mℓ
5-Mercapto-1,2,4-triazole	0.4 g
Water was added to	1.0 ℓ
pH was adjusted to	6.5

Images of the samples after development were visually observed to evaluate the mottles thereof and classify them into the following four ranks. The results are shown in Table 1.

A: No mottles
B: Only a very few mottles
C: Slight mottles
D: Heavy mottles

Table 1

Sample No.	SRa value	Coating speed	Viscosity		Mottle
			First layer	Second layer
1 (X)	2.0 µm	100 m/min	9.0	9.0	D
2 (Y)	0.8 µm	100 m/min	9.0	9.0	B
3 (Y)	0.6 µm	100 m/min	9.0	9.0	A
4 (Y)	0.6 µm	140 m/min	9.0	9.0	B
5 (Y)	0.6 µm	140 m/min	10.0	18.0	A
6 (Y)	0.6 µm	140 m/min	12.0	25.0	A
7 (X)	2.0 µm	40 m/min	9.0	9.0	C
X: Comparative Example, Y: Present Invention

The results shown in Table 1 exhibit that there are no mottles observed in the samples of the invention, in which the support with a low SRa value is used, and that the better results are obtained when the viscosity of the second layer is higher.

Claims

1. A silver halide photographic paper, comprising a paper support coated on both sides with a polyolefin, and, provided thereon, light-sensitive layers comprising a red-sensitive silver halide emulsion layer, a green-sensitive silver halide emulsion layer, and a blue-sensitive silver halide emulsion layer, in this sequence from the support, wherein:
the support has an average center surface roughness of not more than 1.0 µm; and
the light-sensitive layers have been obtained by coating solutions thereof on the support at a speed of not slower than 60 meter/minute.

2. A paper according to claim 1, which further comprises an antihalation layer, an intermediate layer, a UV absorbing layer and a protective layer.

3. A paper according to claim 2, which has been obtained by coating at least one layer of the first to fifth layers from the support with a solution having a viscosity of from 15 to 60 cps (0.015 to 0.06 Pas).

4. A process for preparing a paper as defined in any one of claims 1 to 3, which comprises coating the light-sensitive layers on the support at a speed of not slower than 60 meter/minute.