JPH04319948A - Silver halide photographic paper - Google Patents

Abstract

PURPOSE:To improve a typewriter printing property on a back coating layer surface in a printer by containing gelatin, inorganic matting chemicals, and polymer latex of at least 1 g/m<2> or more. CONSTITUTION:Gelatin, an inorganic matting agent, and polymer latex of at least 1g/m<2> or more are contained in a back coating layer using a the polyolefin resin coating paper of a basis weight of 170g/m<2> or less. Moreover the absorption quantity of the back coating layer is made 300wt.% or less to a whole binder quantity having a main body of the gelatin. In this case, a gelatin quantity of 1-10g/cm<2> degree is needed usually. Moreover an inorganic substance, having a mean particle diameter of 0.2-10mu, is useful as the inorganic matting agent, and e.g. such as silicone dioxide, calcium carbonate, magnesium carbonate, and titanium oxide are cited. A content of the inorganic matting agent is 5-50wt.% to a gelatin content.

Description

[Detailed description of the invention]

0001

[Field of Industrial Application] The present invention relates to thin silver halide photographic paper (hereinafter referred to as photographic paper), and in particular to improving the type printability of the back coat layer surface and preventing stains on the back coat layer surface during development processing. Concerning improved photographic paper.

0002

BACKGROUND OF THE INVENTION Photographic papers are usually provided with a back coat layer on the support surface opposite to the silver halide emulsion constituent layer for various purposes, such as anti-curl, antistatic properties, and ease of writing. To prevent curling, a gelatin layer is generally provided on the back side to maintain the curl balance with the silver halide emulsion constituent layers on the front side.

Regarding antistatic properties, for example, colloidal silica described in Japanese Patent Publication No. 45-30298, colloidal alumina described in Japanese Patent Publication No. 52-18020, and colloidal alumina described in Japanese Patent Publication No. 58-9408 are used to provide antistatic properties.
The use of various carboxyl group-containing compounds as described in the above patent is known. In addition, special public service 57-1298
Ethylene maleic anhydride copolymer described in No. 0, carbon number 4 described in JP-A-55-69139
Water-soluble polymer compounds or salts thereof obtained by copolymerizing the above ethylenically unsaturated copolymerizable monomers with maleic anhydride; The use of organic polymeric antistatic agents such as coalescing anionic polyelectrolytes is also known.

[0004] In addition, in order to make it easier to write with a pencil, for example, barium sulfate as described in Japanese Patent Publication No. 57-53940, silicon dioxide as described in Japanese Patent Application Laid-open No. 118241-1980, and carbonic acid are used. The use of fine particles of calcium, magnesium carbonate, titanium oxide, aluminum oxide, barium sulfate, glass powder, etc. is known.

However, it has been found that conventional backcoat layers having these compositions have serious drawbacks when it comes to type imprinting onto the surface of the backcoat layer in a printer.

[0006] In other words, as has been frequently done in recent years, in order to automatically cut a roll of silver halide photographic material by clearly marking the boundaries between the screens, or to write information about the screen, Type printing is sometimes performed on the back coat layer on the back side of silver halide photographic materials, but this type ink may be washed away in the processing bath or the color may become diluted, making it unable to fully demonstrate its function. There has occurred. In particular, in the case of multilayer silver halide color photographic paper, most of which is automatically printed and cut in roll form, the printability on the back coat layer surface in the printer is an important characteristic, and There was a strong demand for multilayer silver halide color photographic paper with clear printing on the back coat layer in processing machines.

By the way, type printing as used in this specification refers to ink or a substrate such as a type ribbon containing ink between the back coat layer surface of a silver halide photographic material and a type consisting of dots or inscriptions. This indicates that the ink is printed in the form of a type on the surface of the back coat layer by intervening and pressing, preferably by an impact method.

Furthermore, as already mentioned, silver halide photographic materials having a hydrophobic support are characterized by so-called rapid processing, in which the development processing time is shortened. However, if a silver halide photographic material having a hydrophobic support with a back coat layer on which type printing has been applied is developed after 60 minutes or more, especially 3 hours or more, after type printing, Although it is possible to obtain prints with clear type imprinting even after processing,
Within 60 minutes after type printing, especially the shorter the time after type printing, the poorer the type printing performance after development processing, and in extreme cases, almost no type printing remains. It has been found that serious problems arise which are completely contrary to the rapid processability benefits of silver halide photographic materials having transparent supports.

In particular, in the case of the above-mentioned thin photographic paper, a certain amount of gelatin is required in the back coat layer on the back side as a countermeasure against curling, and multiple layers of silver halide emulsion constituent layers are provided as in color photographic paper. The amount of gelatin adhered to paper is generally around 4 to 13 g/m2. Therefore, thin color photographic paper using base paper with a basis weight of 170 g/m2 or less has at least 1 g of gelatin attached to the back coat layer on the back side to prevent curling. /m2 or more of gelatin must be contained. When the amount of gelatin attached to the backcoat layer increases as described above, there is a drawback that the type printability of the backcoat layer surface in the printer described above deteriorates significantly.

0010

SUMMARY OF THE INVENTION An object of the present invention is to provide a silver halide photographic paper with improved type printing properties on the back coat layer surface in a printer. Another object of the present invention is to provide a silver halide photographic paper in which staining on the surface of the back coat layer during development processing is improved.

[0011]

[Means for Solving the Problems] The first object of the present invention is to
This was achieved by containing at least 1 g/m2 of gelatin, an inorganic matting agent, and a polymer latex in the back coat layer of a silver halide photographic paper using polyolefin resin-coated paper with a basis weight of 170 g/m2 or less. . The second object of the present invention was achieved by controlling the water absorption amount of the back coat layer to 300% by weight or less based on the total amount of binder mainly composed of gelatin.

[0012] In the present invention, the polyolefin resin-coated paper with a basis weight of 170 g/m2 or less is a base paper coated with a hydrophobic resin such as polyethylene on both sides, and the total weight of the base paper layer and the polyethylene resin layer is 170 g/m2 or less. It refers to a thin support of less than m2, and generally has a basis weight of 100 to 17
0g/m2. Photographic paper using this support includes thin color photographic paper and thin black and white photographic paper, and thin color photographic paper is used for postcards attached to New Year's postcards and the like.

The back coat layer of thin photographic paper has an important role of preventing curl, and in order to maintain the curl balance, the back coat layer contains an amount of gelatin corresponding to the amount of gelatin contained in the silver halide emulsion constituent layer. It is necessary to contain it, usually in an amount of about 1 to 10 g/m2, preferably in a range of 2 to 7 g/m2.

[0014] As the inorganic matting agent used in the present invention, an inorganic powder having an average particle size of 0.2μ to 10μ, preferably 1μ to 5μ is useful, such as silicon dioxide, calcium carbonate, magnesium carbonate, titanium oxide, etc. Silicon dioxide is particularly preferably used. The content of the inorganic matting agent in the back coat layer is 5% to 50% by weight, preferably 10% to 40% by weight based on the gelatin content.
It is.

The polymer latex used in the present invention is an aqueous dispersion of a water-insoluble polymer with an average particle size of 20 mμ to 200 mμ, such as acrylic latex, vinyl acetate latex, styrene-butadiene latex, acrylonitrile-butadiene latex, etc. is useful,
The content of the polymer latex in the back coat layer is 1% to 30% by weight, preferably 3% to 10% by weight based on the gelatin content.

The back coat layer of the present invention may contain other water-soluble polymers, hardeners, surfactants, etc., and any of these commonly used in photographic materials can be used. . In a backcoat layer containing 1 g/m2 or more of gelatin, a polymer latex and an inorganic matting agent are indispensable in order to improve the type imprintability on the backcoat layer surface in the printer described above. However, depending on the type of processing liquid and processing conditions, the back coat layer containing polymer latex may become stained. In order to prevent this staining, it has been found that it is effective to limit the amount of liquid absorbed by the back coat layer in the processing liquid. That is, by limiting the amount of water absorbed by all the binders mainly composed of gelatin contained in the back coat layer, it was possible to prevent the back coat layer from being stained in the processing solution.

The amount of water absorbed in the present invention refers to the amount of water absorbed by the back coat layer when the back coat layer is immersed in pure water at 20° C. for 1 minute, that is, the total amount of water absorbed by the back coat layer including gelatin and other water-soluble polymers is the degree of swelling in water.

In the present invention, the water absorption amount of the back coat layer is 3% relative to the total amount of binder in the back coat layer.
00% by weight or less, preferably 200% by weight or less,
Most preferred is a range of 130% to 200% by weight. The amount of water absorbed by the back coat layer can be adjusted by adjusting the amount of hardener and by heating the final product coated with the back coat layer and emulsion layer.

[0019]

[Examples] Next, the present invention will be explained in detail with reference to Examples.

Example 1 Base paper coated on both sides with polyethylene resin, basis weight 150g
A back coat layer having the composition shown in Table 1 was coated on a thin base paper of 1/m2.

[0021]

[Table 1] (Note 1) The content of each component is the solid content per 1 m2

0
[022] Blue-sensitive silver chlorobromide containing a yellow coupler was placed on the surface of the polyethylene-coated paper coated with these back coat layers (that is, on the side of the support opposite to the side on which the back coat layer was coated) in the order adjacent to the support. Coating a gelatin emulsion layer and an intermediate layer, a green-sensitive silver chlorobromide gelatin emulsion layer containing a magenta coupler and an ultraviolet absorption layer containing an ultraviolet absorber, and a red-sensitive silver chlorobromide gelatin emulsion layer containing a cyan coupler and its protective layer. A multilayer silver halide color photographic paper was prepared. After each sample obtained as described above was heated at 40° C. for one day, the type imprintability of the back coat layer surface was evaluated by the following method.

Using an impact printer installed in an automatic printer, a type ribbon (for Kodak back printer manufactured by Eastman Kodak Company) was interposed between the back coat layer surface of the sample and the type, and numbers and numbers were printed on the back coat layer surface. Information consisting of letters, lines, etc. was printed in type. Five minutes after the type was printed, it was processed with a roll processor and the state of disappearance of the type was examined. As a result, in samples A and B of the present invention, the type imprint remained almost completely without disappearing, but in other samples C, D, and E, the type imprint had disappeared to the extent that it was difficult to read.

Example 2 Next, a test was conducted on the stain resistance of the back surface during development. The samples were prepared in the same manner as in Example 1 except for the back coat layer shown in Table 2.

[0025]

[Table 2] (Note 1) The content of each component is the solid content per 1 m2

0
[026] The multilayer silver halide color photographic paper having the above-mentioned back coat layer was heated at 40°C for one day, then processed with a roll processor, and the state of stains on the surface of the back coat layer was observed. The water absorption amount of the back coat layer was also measured by the following method.

[0027] The sample is cut into 10 cm x 10 cm, and its weight (a) is measured. After the cut sample is immersed in pure water at 20° C. for 1 minute, water droplets on the surface of the back coat layer are gently wiped off with wax paper, and the weight (b) is immediately measured. At this time, the silver halide color emulsion layer on the opposite side should be peeled off in advance, or a waterproof adhesive tape should be attached to the surface to prevent water from seeping in. Back coat layer 1
The water absorption amount (c) per m2 is determined by the following formula.

[0028]

[Math. 1] (C)={(b)-(a)}×100

002
9] Table 3 shows the results of the state of dirt on the back coat layer surface and the amount of water absorption.

[0029]

[Table 3]

From the above results, if the water absorption amount of the back coat layer is less than 300% of the gelatin content of the present invention, stains on the surface of the back coat layer will be hardly noticeable;
%, dirt becomes noticeable.

[0031]

Effect of the invention: It is necessary to contain gelatin in the back coat layer of photographic paper using thin base paper with a basis weight of 170 g/m2 or less to prevent curling.
In the back coat layer containing the above, type printing properties in a printer were improved by containing an inorganic matting agent in the polymer latex. In addition, in the above-mentioned back coat layer, the water absorption amount of the back coat layer is 300% by weight based on the total amount of binder mainly composed of gelatin.
By doing the following, it was possible to prevent staining of the back coat layer surface during development processing.

Claims (2)

[Claims] Claim 1: In the back coat layer of a silver halide photographic paper using a thin polyolefin resin-coated paper with a basis weight of 170 g/m2 or less as a support, gelatin, an inorganic matting agent, and a polymer in an amount of at least 1 g/m2 or more. A silver halide photographic paper characterized by containing latex. 2. The silver halide photographic paper according to claim 1, wherein the water absorption amount of the back coat layer is 300% by weight or less based on the total amount of the binder mainly consisting of gelatin.