JPH0345818B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to an improvement in an image forming method using physical development. Physical development is a visible image made of metal particles grown by treating fine metal nuclei forming a latent image with a developer containing reducible metal ions and a reducing agent (hereinafter often referred to as "physical developer"). It is generally known as a means of forming silver images. In recent years, non-silver salt image forming materials have been reconsidered due to the limited resources of silver salts, but the only practical image forming method that uses physical development is the method of forming conductive patterns on printed circuit boards. There is only that. In view of these circumstances, the present inventor conducted research in search of a method for producing images with resolution and tone reproducibility equivalent to those using silver salt image forming materials, while essentially using non-silver salt materials. have already developed a series of image forming methods using physical development (1982 Patent Application No. 182660, Patent Application No. 182661, etc.).
These methods were developed based on the knowledge that a compound having a diazo group or an azide group is not only photodegradable, but also effectively suppresses the above-mentioned physical development due to its presence. Among a series of methods, one typical image forming method is one in which an image forming layer is provided on a support, and the image forming layer is reduced to form a metal compound that becomes a metal development nucleus and a diazo group. or an image forming material comprising a hydrophilic binder layer containing a compound having an azide group.
The image forming layer is subjected to pattern exposure, and then,
a first development step of contacting the image forming layer with a reducing agent to form metal development nuclei in the image forming layer; and contacting the image forming layer with a physical developer containing reducible metal ions and a reducing agent. and a second development step of forming an image consisting of metal particles precipitated and grown by reduction of the reducible metal ions centering on the metal development nuclei in the exposed area (Showa era). 182661). The above method has a transmission optical density of 4 or more, and can form a black image with gradations as required; This method has advantages such as the high resolution and the ability to replace images produced by silver halide photography; the resulting images are metal images and can therefore be corrected using ordinary reducing fluid; are doing. However, the above method also has one problem. That is, the metal development nuclei obtained in the first development step of the above method are not yet stable and may lose their function as nuclei before proceeding to the next development step. For example, in order to automate development, when a counter roll used for ordinary silver film is used as a transport mechanism from the first development process to the second development process, when the image forming layer comes into contact with the roll, , the metal development nuclei are transferred to the roll or deactivated and lose their function as nuclei. For this reason, even if physical development is performed in the second development step, image formation may be partially or not performed at all. The present invention relates to the above-mentioned image forming method (hereinafter referred to as "basic method").
The purpose of this invention is to provide an improved method for the above-described first development process, and more specifically, to stabilize the image-forming material after the first development step and ultimately provide an image with excellent quality. It is. According to the research of the present inventors, in order to achieve the above object, in the first developing step of the above basic method,
Instead of simply reducing the image forming material after pattern exposure to generate metal development nuclei, a physical developer (first developer) containing a boron-based reducing agent, which is a relatively strong reducing agent, and reducible metal ions is used. A physical developer solution (solution) containing a relatively weak reducing agent and reducible metal ions is used to not only generate physical development nuclei but also to grow the development nuclei to the extent of giving a relatively thin visible image. It has been found that it is effective to increase the transmittance of visible images by treatment with a second developing solution. If such a method is adopted, physical development nuclei will have grown after the first development process, so even when the image forming material is conveyed by the opposing rolls, the function as nuclei in the second development process will not be impaired. do not have. In addition, because physical development is performed using a relatively weak reducing agent in the second development step, resolution, gradation reproducibility, etc. The transmission density of the visible image can be increased without compromising the image quality. The image forming method of the present invention is based on the above-mentioned knowledge, and more specifically, an image forming layer is provided on a support, and a metal compound that becomes a metal development nucleus when the image forming layer is reduced; The image-forming layer of an image-forming material consisting of a hydrophilic binder layer containing a compound having a diazo group or an azide group is subjected to pattern exposure, and then a compound containing a boron-based reducing agent and a reducible metal ion is applied to the image-forming layer. 1 physical developer is brought into contact with the exposed area to precipitate the metal and the transmission density is determined.
0.5 or less, and further contact with a second physical developer containing a reducing agent weaker than the boron-based reducing agent and a reducible metal ion to increase the transmission density of the visible image to 4.0 or more. It is characterized by: The image forming method of the present invention will be explained in more detail below. In the following description, "%" and "part" are based on weight unless otherwise specified. Image Forming Material As its conceptual layered structure is shown in FIG.
It has an image forming layer 2 provided thereon and is similar to that used in the basic method, but will be explained below for convenience. As the support 1, any solid material such as glass, wood, paper, plastic film, woven fabric, non-woven fabric can be used, and among them, plastic films such as polyester film and triacetate film are particularly preferably used. These supports 1 are provided with the image forming layer 2 after being pretreated to improve adhesion, such as corona discharge treatment and primer treatment, if necessary. The image forming layer 2 is formed by dissolving or dispersing in a hydrophilic binder layer a metal compound that is reduced to become metal development nuclei and a compound having a diazo group or an azide group (hereinafter referred to as a "development inhibitor"). Examples of binders include natural polymers such as gelatin, casein, glue, gum arabic, and shellac, carboxymethylcellulose, egg albumin, polyvinyl alcohol (partially saponified polyvinyl acetate), polyacrylic acid, polyacrylamide, polyvinylpyrrolidone, and polyvinyl pyrrolidone. Ethylene oxide, maleic anhydride copolymers, etc. are used, but other resins than the above can also be used as long as they are water-soluble or hydrophilic resins. The degree of hydrophilicity required for the binder is such that when the image forming layer 2 is formed and brought into contact with a physical developer, the physical developer permeates into the image forming layer 2 to enable physical development. Metal compounds that are reduced to give metal development nuclei include water-soluble salts such as chlorides and nitrates of noble metals such as palladium, gold, silver, platinum, and copper, such as those contained in the activator solution for electroless plating. Water-soluble salts such as palladium chloride, silver nitrate, and gold tetrachloride are used. Among these, water-soluble salts of palladium, gold, platinum, and copper, particularly water-soluble salts of palladium, are preferably used. The image forming layer 2 is preferably made of an aqueous solution of the metal compound mentioned above (a commercially available activator liquid for electroless plating can be used as it is),
It is mixed with a binder aqueous solution along with a development inhibitor to form a liquid with a viscosity of about 10 to 1000 centipoise suitable for coating, which is coated onto the support 1 and dried to obtain a coating film of usually 0.1 to 30 μm. . In addition to the water mentioned above, a mixed solvent of water and a water-miscible solvent such as a lower alcohol, ketone, or ether may also be used as the solvent. Examples of compounds having a diazo group or an azide group used as development inhibitors include water-soluble zinc chloride double salts, sulfates, and phosphates having a diazo group, or diazo resins obtained from these. is preferably used. More specifically, p-N,N-diethylaminobenzenediazonium chloride zinc chloride double salt, p-N
-ethyl-N-β-hydroxyethylaminobenzenediazonium chloride zinc chloride double salt, p-
N,N-dimethylaminobenzenediazonium chloride zinc chloride double salt, 4-morpholinobenzenediazonium chloride zinc chloride double salt, 4-morpholino-2,5-diethoxybenzenediazonium chloride zinc chloride double salt, 4-morpholino-
2,5-dibutoxybenzenediazonium chloride zinc chloride double salt, 4-benzoylamino-2,5
-Diethoxybenzenediazonium chloride zinc chloride double salt, 4-(4'-methoxybenzoylamino)
-2,5-diethoxybenzenediazonium chloride zinc chloride double salt, 4-(p-toluylmercapto)-2,5-dimethoxybenzenediazonium chloride zinc chloride double salt, 4-diazodiphenylamine zinc chloride double salt, 4- Diazo-4'-methoxydiphenylamine zinc chloride double salt, 4-diazo-3-
Methoxy-diphenylamine zinc chloride double salt, sulfates and phosphates corresponding to the above-mentioned zinc chloride double salt, and diazo resin which is a reaction product of these diazonium compounds and paraformaldehyde can be suitably used. Further, as the azide compound, for example, p-azidobenzaldehyde,
p-azidoacetophenone, p-azidobenzoic acid, p-azidobenzalacetophenone, p-azidobenzalacetone, 4,4'-diazidochalcone, 2,6-bis(4'-azidobenzal)- Acetone, 4,4'-diazidostilbene-2,2'-disulfonic acid, p-azidobenzoyl chloride, 3
-azido phthalic anhydride, 4,4'-diazido diphenyl sulfone, p-azido cinnamic acid, sodium 4,4'-diazidobenzoylacetone-2,2'-sulfonate, etc. are used. Further, as the development inhibitor, compounds other than those mentioned above can also be used as long as they are water-soluble and have a diazo group or an azide group. The image forming layer 2 contains the binder 100 described above.
parts: 0.01 to 100 parts of metal compounds, especially
0.01 to 1 part, 1 to 100 parts of development inhibitor, especially 5 to 1 part
Preferably, it is contained in a proportion of 50 parts. After forming the image forming layer 2, hardening treatment is desirably performed in order to prevent elution of the binder into the developer during physical development or damage to the image forming layer. For hardening, for example, the following compound is mixed in the coating solution for forming the image forming layer 2 at a ratio of 0.1 to 50 parts per 100 parts of the binder, or an aqueous solution thereof is applied onto the image forming layer. or by immersing the image forming layer in an aqueous solution thereof: Al compounds such as potassium alum and ammonium alum; Cr compounds such as chromium alum and chromium sulfate;
Aldehydes such as formaldehyde, glyoxal, glutaraldehyde, 2-methylglutaraldehyde, succinaldehyde; O-benzoquinone, p-benzoquinone, cyclohexane-1,2
-dione, diketones such as cyclopentane-1,2-dione, diacetyl, 2,3-pentanedione, 2,5-hexanedione, 2,5-hexenedione; epoxides such as triglycidyl isocyanurate; tetraphthaloyl Chloride, 4,4'-
Diphenylmethane disulfonyl chloride, 4,
Acid anhydrides such as 4'-diphenylmethanedisulfonyl chloride; tannic acid, gallic acid, 2,4-
Dichloro-6-hydroxy-S-triazine, as well as general formulas R ₂ NPOX ₂ , (R ₂ N) _o POX _3-o ,

【formula】

[Formula] and R-N=C=N-R ¹ (where R is an alkyl group having 2 to 6 carbon atoms, R ¹ is a (CH ₃ ) ₃ N ⁺ (CH ₃ ) ₃ X ^- group, and X is F or Cl, n is 1 or 2) Phosphorus compound or carbodiimide; styrene/maleic acid copolymer, vinylpyrrolidone/maleic acid copolymer, vinyl methyl ether/maleic acid copolymer, ethyleneimine/maleic acid copolymer resins such as methacrylic acid/methacrylonitrile copolymers, polymethacrylamide, and methacrylic acid ester copolymers.
Organic carboxylic acids such as glutaric acid, succinic acid, and hydroxycarboxylic acids such as malic acid, lactic acid, citric acid, aspartic acid, gelcholic acid, and tartaric acid can also be used as dicarboxylic acids. Further, nitrogen-containing compounds such as dimethylol urea and trimethylol melamine can also be used. Image Forming Method According to the present invention, an image forming material A as described above
To form an image using the image forming layer 2, first, a transparent original 3 is placed on the image forming layer 2 as shown in FIG.
Pattern exposure is performed through the . Thereby, in the exposure section 2A, the development inhibitor can be decomposed selectively and to a degree according to the amount of exposure. Any light source that can decompose the diazo compound or azide compound described above can be used as the light source. For example, an ultra-high-pressure mercury lamp, a high-pressure mercury lamp, a low-pressure mercury lamp, a metal halide lamp, an arc lamp, a chemical lamp, a xenon lamp, an Ar laser, etc. can be used. Depending on the desired image gradation, for example, when using ultraviolet light with a center wavelength of 405 nm, ^the
It is sufficient to expose for 10 to 200 seconds at an intensity of 300w/ ^m2 . Next, the image forming layer 2 having a latent image in which the development inhibitor has been decomposed in a pattern is brought into contact with the first developer by dipping or coating by pattern exposure in this way, and the image forming layer 2 is coated with a metal compound. Metal nuclei are generated by reduction, and a thin visible image 2B with a transmission density of 0.5 or less is given to the exposed area (Fig. 3). As the first developer, an aqueous solution containing a water-soluble reducible metal salt and a boron-based reducing agent is used, if necessary, in a heated state. As the reducible metal salt, for example, water-soluble salts of heavy metals other than noble metals such as nickel, cobalt, iron, and VIb group metals such as chromium are used alone or in combination. Specifically, for example, the following are used. Heavy metal halides such as cobaltous chloride, cobaltous iodide, ferrous bromide, ferrous chloride, chromic bromide, chromic iodide; nickel sulfate,
Heavy metal sulfates such as ferrous sulfate, cobaltous sulfate, and chromic sulfate; Heavy metal nitrates such as nickel nitrate, ferrous nitrate, cobaltous nitrate, and chromic nitrate; ferrous acetate, acetic acid Organic acid salts of heavy metals such as cobaltous cobalt and dichromic acetate. These reducible metal salts are contained in the first developer in a proportion of, for example, 1 to 100 g/g/. Examples of the boron-based reducing agent to be included in the first developer include sodium borohydride, hydrazine, diethylamine borane, dimethylamine borane, trimethylamine borane, borane, diborane, methyldiborane, diborazane, borazine, borazine, t- Butylamineborazane, pyridineborane, 2,6-lutidineborane, ethylenediamineborane, hydrazineborane, dimethylphosphineborane, phenylphosphineborane, dimethylaldineborane, phenylaldineborane, dimethylstibineborane, diethylstivineborane, etc. Can be used. These boron-based reducing agents are used in the physical developer at a rate of, for example, 0.1 to 50 g/. In addition to the above-described reducible metal salt and boron-based reducing agent, in the first developer, in order to prevent heavy metal ions generated by dissolving the reducible metal salt from precipitating as hydroxide, For example, from monocarboxylic acids: dicarboxylic acids; hydroxycarboxylic acids such as malic acid and lactic acid; organic carboxylic acids such as succinic acid, citric acid, aspartic acid, glycolic acid, tartaric acid, ethylenediaminetetraacetic acid, gluconic acid, sugar acid, and quinic acid. One or more complexing agents may be included. For example, 1 to 100 g of these complex chloride agents may be added to the first developer.
used at a rate of Furthermore, the first developer contains PH regulators such as acids and bases, buffers, preservatives, brighteners, and surfactants in order to improve the storage stability and operability of the developer and the quality of the resulting images. Agents and the like are added as necessary according to conventional methods. The transmission density of image 2B (shadow area) after the first development step is suppressed to 0.5 or less. If the development is continued beyond this point, many physical development nuclei will be generated in the image forming layer, which will exceed the inhibitory ability of the development inhibitor during subsequent treatment with the second developer, resulting in background fog in non-image areas. Therefore, the resolution and gradation reproducibility of the finally obtained image deteriorate. The lower limit of the density of the image 2B is sufficient as long as it can be perceived as a visible image, and the transmission density is usually 0.08 or higher. In this way, the metal particles grow around the metal development nuclei, and do not lose their activity even if they come into contact with the transport rolls to some extent. However, it goes without saying that it is still better to avoid contact of the image forming layer with the roll or the like as much as possible. The image forming material having the visible image 2B after the first development is then conveyed to a second development step, where it contains a reducible metal salt and a reducing agent weaker than the boron-based reducing agent used in the first development step. By further processing with a second developer, a visible image 4C is formed in which the transmission density of the visible image 4B is improved to 4.0 or more (FIG. 4). As the reducible metal salt in the second developer, the first
In addition to water-soluble salts such as nickel, cobalt, iron, and chromium used in the developer, water-soluble salts of heavy metals such as zinc, tin, cadmium, lead, copper, platinum, silver, and gold are also used. This is because the reducing agent in the second developer is weak and is relatively easily reduced, and salts of these metals can also be stably contained. Specifically, in addition to those used in the first developer,
Halides such as cuprous chloride and gold chloride; sulfates of copper sulfate; nitrates such as copper nitrate; and organic acid salts such as copper formate are also used. The reducible metal salt in the second developer may be the same or different from that in the first developer, and two or more types can be used in combination. These reducible metal salts are used in the second developer at a concentration of, for example, 1 to 100 g/. Further, as the reducing agent in the second developer, for example, sodium hypophosphite, hydrazine, formalin, tartaric acid, glucose, phosphorous acid, etc. are used. These reducing agents may be present in the second developer, for example.
It is used at a rate of 0.1 to 100g/. Regarding points other than the above, the second developer is not particularly different from the first developer, and is similar to the first developer, including complexing agents, PH regulators, buffers, preservatives, surfactants, etc. auxiliaries may be included as necessary. The second development is performed in order to improve the density of the visible image formed in the first development without causing a decrease in resolution and gradation reproducibility. This is proceeded by contact treatment with a second developer. At this time, hydrogen bubbles are generated on the image forming layer and must be removed. Hydrogen bubble removal during the second development process is also possible, for example, by passing the imaging material between opposed rolls. The treatment with the second developer is carried out for about 5 seconds to 180 seconds, depending on the temperature of the developer, until the required concentration is obtained. After the second development, the imaging material is optionally
By post-processing such as washing with water and drying, a black image with a transmission density of 4.0 or more and good tone reproducibility can be obtained, and a metal image can also be formed by performing the second development for a relatively long period of time. As described above, according to the present invention, first development and second development are performed on an image forming material containing a metal development nucleus precursor and a diazo development inhibitor after the development inhibitor is selectively decomposed by pattern exposure. In the first development, a boron-based reducing agent, which is a relatively strong reducing agent, is used to simultaneously form metal development nuclei and an initial visible image, and in the second development,
By using a relatively weak reducing agent to improve the density of the visible image, it is possible to stabilize the image after the first development and finally obtain an image with a transmission density of 4.0 or more and good tone reproducibility. Hereinafter, the present invention will be explained in more detail with reference to Examples. Example 1 1 g of PdCl ₂ was dissolved in 1000 ml of water together with 10 ml of HCl, and 10 g of the resulting _two PdCl solutions was used to prepare a sensitive material (coating solution for forming an image forming layer) having the following composition. PdCl ₂ liquid with the above composition 10g PVA (Nippon Gosei Kagaku, Gosenal T-
330) 10% aqueous solution 20g Diazoresin (Shinko Technology D-011) 20% 〃 2g Glyoxal 1% 〃 0.2g Polyester film (Toray, Lumirror S-100) in which the above-mentioned sensitive material was previously plasma treated
#) and dried to obtain a 4μ coating film. Sensitive film (image forming material) obtained above
The negative film was exposed for 1 minute using an ultra-high pressure mercury lamp 3K.W printer (distance 100 cm from the light source). Next, the above-mentioned sensitive film was immersed in an electroless nickel plating bath having the composition shown below at 45° C. for 30 seconds to obtain a visible image with a transmission density of about 0.08 in the exposed area. Nickel sulfate 20g / Potassium sodium tartrate 40g / Sodium borohydride 2.3g / PH adjustment (NaOH) 12.5 Next, as a second development, an electroless nickel plating bath with the following composition was prepared in a bath using a roll conveying device.
The above photosensitive film was processed at 20°C for 40 seconds. Nickel hypophosphite 26.7g/boric acid 12g/ammonium sulfate 2.6g/sodium acetate 47g/PH 5.5-6.0 As a result, an image with a transmission density of 4.10 and good tone reproducibility was obtained. Example 2 A sensitive film was obtained in the same manner as in Example 1 and exposed. Next, the above-mentioned photosensitive film was immersed for 20 seconds in an electroless nickel plating bath (manufactured by Okuno Pharmaceutical Co., Ltd., Shiba Nikkel stock solution) containing a boron reducing agent, and a first exposure was performed to obtain a visible image with a transmission density of 0.10 in the exposed area. then the second
For development, a hypophosphorous acid-based electroless plating TMP chemical nickel (manufactured by Okuno Pharmaceutical Co., Ltd.) is placed in a bath with a roll conveyance device, and the above-mentioned sensitive film is processed in this bath for 40 seconds to produce a black color with a transmission density of 4.0. Images with good tone reproducibility were obtained. Comparative Example 1 A film was prepared in the same manner as in Example 1, exposed in the same manner, and then immersed in the following reduction bath at 30° C. for 45 seconds for reduction treatment. At this point, the visible image is
I wasn't getting it. SnCl ₂ 1g HCl 40ml H ₂ O 200ml Next, using a physical developer at 90°C with the following composition,
When the above film was placed in a bath using a roll conveyance system and processed (40 seconds), an image with a transmission density of 4.2 was obtained, but the image was partially missing. Nickel chloride 30g Sodium hypophosphite 10g Sodium oxyacetate 50g Water 900g Example 3 A sensitive material having the following composition was prepared, and a sensitive film was produced in the same manner as in Example 1. PdCl _{dihydrochloric} acid aqueous solution (Nippon Kanisen Retsudsumer) 20g PVA (Nippon Gosei Kagaku, Gosenal T-
330H) 10% aqueous solution 20g Diazoresin (Shinko Giken D-012)
20% aqueous solution 1.5g Chromium alum 1% aqueous solution 0.4g The above sensitive film was exposed with a diazocopy lamp (Ricoh Histart 4) for 40 seconds by overlaying it with a negative film, and then a boron-based electroless film was used as the first development. Treated for 25 seconds at 45℃ in a metal bath (manufactured by Okuno Pharmaceutical Co., Ltd., Shiba Niktsukel) to achieve a transmission density in the exposed area.
A visible image of 0.09 was obtained. Next, as a second development, hypophosphorous acid-based electroless plating solution (TMP Chemical Nickel) was used.
into a bathtub that uses a roll conveyance method.
When processed at 20°C for 40 seconds, a black image with an even transmission density of 4.20 was obtained. Example 4 Activator PdCl ₂ 2g HCl 20ml H ₂ O 1000c.c. Sensitizer SnCl ₂ 1g HCl 40ml H ₂ O 100c.c. Activator (PdCl ₂ hydrochloric acid aqueous solution) and sensitizer (SnCl ₂ hydrochloric acid Aqueous solution) were mixed at a weight ratio of 2:1, and a hydrochloric acid aqueous solution in which Pd nuclei thus prepared were dispersed was used to prepare a sensitive material (coating liquid for forming an image forming layer) having the following composition. Pd nuclear dispersion hydrochloric acid aqueous solution 30g Gelatin (Nitta Gelatin P-2151) 30% aqueous solution 10g Diazoresin (Shinko Giken D-011) 20%
Aqueous solution 25g Methyl vinyl ether/maleic anhydride copolymer 5.0g (Gokyo Sangyo Gantoretsu 149) 5% aqueous solution A polyester film (Toray Mirror S, 100#) and sufficiently dried to produce an image forming material (sensitive film) having an image forming layer with a thickness of 4 μm. A 2K.W ultra-high pressure mercury lamp is applied to the coating film of the above-mentioned sensitive film.
The negative film was closely exposed for 2 minutes using a printer (distance 100 cm from the light source). Next, the first development process and the second development process were performed in the same manner as in Example 1, and an image with a transmission density of 4.0 with no development unevenness and good tone reproducibility was obtained, and a halftone dot of 150 lines on the resolution chart was obtained. Resolution was also good. Comparative Example 2 The same procedure as in Example 4 was used, except that the first development process in Example 1 was carried out at 45°C for 50 seconds, and a black image with a transmission density of 1.6 was obtained, but the shadow area was However, I was overweight and the reproducibility of my tone was not good. Furthermore, when a second development was performed in the same manner as in Example 4, the non-image areas were also plated, resulting in background fog.

[Brief explanation of drawings]

FIG. 1 is a schematic cross-sectional view in the thickness direction showing the laminated structure of the image forming material used in the present invention, and FIGS. 2 to 4 show intermediate steps of the image forming method of the present invention using the image forming material shown in FIG. FIG. 1...Support, 2...Image forming layer (2A...Exposed area,
2B...light visible image, 2C...dark visible image), 3...transparent original, A...image forming material.

Claims (1)

[Claims] 1 Image formation comprising an image forming layer provided on a support, and a hydrophilic binder layer containing a metal compound that becomes a metal development nucleus when the image forming layer is reduced and a compound having a diazo group or an azide group. The image forming layer of the material is subjected to pattern exposure, and then the image forming layer is brought into contact with a first physical developer containing a boron-based reducing agent and reducible metal ions to precipitate metal in the exposed areas, resulting in a transmission density of 0.5 or less. forming a visible image, and further bringing it into contact with a second physical developer containing a reducing agent weaker than the boron-based reducing agent and reducible metal ions, so that the transmission density of the visible image is 4.0 or more. An image forming method characterized by: