JP2902370B2 - Correction liquid for lithographic printing plate with silver image formed - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

This invention relates to silver-imaged (si)
Lever imaged lithographic printing plates, and in particular to an improved correction solution for silver imaged lithographic printing plates obtained according to the silver salt diffusion transfer method.

[0002]

BACKGROUND OF THE INVENTION In the production of prints from lithographic printing plates, it is often necessary to modify the printing area of the lithographic printing plate in order to obtain a faithful print of the original. In one embodiment, this requires that some of the oleaginous ink receiving areas of the lithographic printing plate be oleaginous ink repellent hydrophilic areas. In the case of silver-plated lithographic printing plates, this usually involves reacting a reactive fluid, which renders the unwanted parts of the silver image hydrophilic, thereby eliminating the ink receptivity of the silver image. This is done by applying to the receptive area. More specifically, the reactive agent reduces the unwanted portions of the silver image photographically or physically formed on the lithographic printing plate by making the unwanted portions of the silver image completely hydrophilic. Removes ink receptivity. The reactive agent is called a correction fluid or a correction agent, whereas the act of rendering part of the silver image completely hydrophilic is called a lithographic printing plate correction.

Generally, portions of a lithographic printing plate prepared by a plate-making method that require correction include portions already existing in a document to be copied, portions generated at the time of exposure, or portions generated by uneven development processing. Part is included.

[0004] That is, for example, if the document contains an unwanted image or has dust, dirty powder, fingerprints and other stains, and furthermore, if a stacked document is used, the exposure will cause shadows. May occur. In order to obtain good prints, such parts must be modified during the prepress and printing stages. Generally, correction is an essential process, and it is therefore preferable that the necessary correction can be made at any stage of the plate making and printing steps.

[0005] Many proposals have been made for lithographic printing plate correction fluids using a silver image as the ink-receiving area.

For example, a correction solution comprising a mercapto or thione group, a hydrophilic group and, in many cases, a water-soluble bromide or iodide is disclosed in JP-A-6-266114 and JP-A-6-2.
66113, JP-A-6-102672, JP-A-6-67
440, JP-A-3-282476, JP-A-1-2549
62, JP-A-51-21901 and JP-A-48-921
01. However, these correction fluids have drawbacks such as harmful effects on the human body due to strong acidity, slow action on silver images and poor storage stability.
Stability on storage can be simulated by keeping the correction fluid at an elevated temperature for a period of time.

[0007]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a correction liquid for a lithographic printing plate with a silver image, which has an improved correction speed.

It is another object of the present invention to provide a correction liquid for a lithographic printing plate having a silver image formed thereon, which has improved storage stability.

[0009] Still other objects of the present invention will become apparent from the following description.

[0010]

According to the present invention, there is provided an iron (III) complex salt of an organic acid, a sulfite or metabisulfite,
5.5 to 8. comprising a silver halide solvent and an accelerator.
An aqueous solution having a pH in the range of 5, wherein the promoter is an organic heterocyclic group having a mercapto or thione group and having no hydrophilic substituents in addition to the mercapto and thione groups. A silver image forming lithographic printing plate correction fluid, wherein the accelerator is present in an amount in the range of 0.04 to 0.4 mole per liter of the correction fluid. The provided lithographic printing plate correction liquid is provided.

According to the present invention, it has been found that a correction fluid having the above composition has a high correction rate and improved storage stability.

Other hydrophilic substituents of the mercapto group according to the invention can be amino groups, ammonium groups, hydroxyl, sulpho groups or carboxyl which are not included in the heterocyclic groups.

The organic heterocyclic compound having a mercapto group or a thione group is preferably a nonionic compound. More preferably, the organic heterocyclic compound having a mercapto group or a thione group contains at least 2 nitrogen atoms, most preferably at least 3 nitrogen atoms in the heterocyclic group.

Examples of suitable accelerators are given in Table 1.

[0015]

[Table 1]

Preferably, the compound is used in an amount ranging from 0.08 to 0.2 mol per liter of correction fluid.

The oxidizing compound is an iron (III) complex salt of an organic acid. Iron (III) refers to iron in the +3 oxidation state. A preferred example of the iron (III) complex salt of an organic acid is an iron (III) complex salt of an aminopolycarboxylic acid, but an iron (III) complex salt of a phosphonic acid can also be used.

The iron (III) complex salt of an organic acid is usually used in the form of a complex salt, but is not limited to iron (III) sulfate, iron (III) chloride,
Using an iron (III) salt such as iron (III) nitrate, ammonium iron (III) sulfate, iron (III) phosphate and the like and an organic acid and / or a salt thereof to form an iron (III) ion complex in solution Can be formed.

The iron (III) complex salt of aminopolycarboxylic acid is a complex of iron (III) ion and aminopolycarboxylic acid or a salt thereof.

Typical examples of aminopolycarboxylic acids and their salts are diethylenetriaminepentaacetic acid and its salts, ethylenediamine-N- (2-oxyethyl) -N, N ',
N'-triacetic acid and its salts, propylenediaminetetraacetic acid and its salts, nitrilotriacetic acid and its salts, cyclohexanediaminetetraacetic acid and its salts, iminodiacetic acid, dihydroxyethylglycine, ethylenediaminetetrapropionic acid and the like. More preferred examples of aminopolycarboxylic acids and salts thereof are ethylenediaminetetraacetic acid (EDTA) and salts thereof.

Typical examples of the phosphonic acids and salts thereof include diethylenetriaminepentamethylenephosphonic acid and salts thereof, cyclohexanediaminetetramethylenephosphonic acid and salts thereof, triethylenetetraminehexamethylenephosphonic acid and salts thereof, and glycol etherdiaminetetramethylene. Phosphonic acid and its salt, 1,2-diaminopropanetetramethylenephosphonic acid and its salt, methyliminodimethylenephosphonic acid and its salt, 1,3-diaminopropan-2-ol tetramethylenephosphonic acid and its salt, ethylenediaminetetra Methylenephosphonic acid and its salts.

It is possible to use organic acid iron (III) complex salts comprising any combination of these organic acid salts and the iron (III) salts.

The organic acid iron (III) complex salt is used to oxidize the silver image used as the ink receptive area, and preferably, the mercapto compound or the like generally used to increase lipophilicity is firmly used. It is used in large quantities to oxidize such absorbed silver images. Preferably, the iron (III) complex is present in an amount of 0.0
It is used in an amount of 7 to 0.7 mol, more preferably 0.15 to 0.35 mol per liter of correction fluid.

Preferably, the correction fluid is more preferably 0.02-0.2 mole per liter of correction fluid, most preferably 0.04-0.1 mole of excess amino per liter of correction fluid. Contains polycarboxylic acids or phosphonic acids.

Preferably, the aminopolycarboxylic acid or phosphonic acid used to form the organic acid iron (III) complex salt and the aminopolycarboxylic acid or phosphonic acid present in an excess amount are aminopolycarboxylic acid or phosphonic acid. And
More preferably they are the same.

The correction fluid is a sulfite or metabisulfite,
Preferably it comprises sulfurous acid, more preferably sodium sulfite. The sulfite is preferably in an amount in the range of 0.06 to 0.6 moles per liter of correction fluid, more preferably 0.12 to 0.28 per liter of correction fluid.
The metabisulfite is preferably present in an amount in the range of 0.03 to 0.3 mole per liter of correction fluid, more preferably 0.06 to 0.36 per liter of correction fluid. It is present in an amount in the range of 0.14 mole.

The correction liquid is a silver halide solvent such as 2
-Mercaptobenzoic acid, cyclic imide, oxazolidone,
Comprising a thiocyanate, an alkanolamine and a thioether disclosed later herein. Preferably, the silver halide solvent is a thiosulfate, more preferably sodium or ammonium thiosulfate. Particularly preferably, the thiosulfate is present in an amount in the range of 0.5 to 5 mol per liter of correction fluid, most preferably 1
It is present in an amount within the range of 1.0 to 2.5 moles per liter.

The correction fluid is 5.5 to 8.5, preferably 6
It has a pH in the range of ８8. The pH is preferably
Buffers, e.g., phosphate buffer, citrate buffer,
Obtained by using an ammonium buffer or a mixture thereof.

The correction fluid is preferably a surfactant, more preferably an amphoteric surfactant as described in US Pat. No. 4,837,122, most preferably n.p. C ₁₆ H ₃₃ N ⁺ (C
^{_{H 3) 2 CH 2 COO -}} ( Switzerland, by LONZA Am
sold as biteric H). The surfactant is preferably used in an amount ranging from 0.3 g to 3 g per liter of correction fluid, more preferably in an amount ranging from 0.6 g to 1.5 g per liter of correction fluid.

The correction fluid may contain water-soluble bromide and / or water-soluble iodide in an amount such that the bromide and / or iodide is soluble in the correction fluid. Examples of such water-soluble bromides and iodides are potassium bromide or potassium iodide, sodium bromide or sodium iodide,
Ammonium bromide or ammonium iodide.

The correction fluid can contain an organic solvent such as alcohol, ether, amide and the like. Preferably, the organic solvent is methoxy-2-propanol.
The organic solvent is more preferably in an amount of 50 ml to 500 ml per liter of correction fluid, most preferably
Used in an amount of 100-300 ml per liter.

The correction fluid is a thickening agent (thickenin).
g., for example, hydroxyethylcellulose and carboxymethylcellulose, preferably in an amount of 30 g to 250 g per liter of correction fluid, more preferably in an amount of 60 g to 120 g per liter of correction fluid.

The correction fluid can be applied to the lithographic printing plate on which the silver image has been formed at any time after the production of the lithographic printing plate. Preferably, the correction fluid can be applied to the lithographic printing plate before starting the printing process, but if necessary, the correction fluid can be applied during printing.

[0034] The correction fluid is preferably a felt tipped core made of felt.
cting pen) and the container is applied on a silver imaged lithographic printing plate using a correction pen whose filling is filled with correction liquid. Alternatively, a correction gel, a correction fluid containing a thickening agent, can be used for correction on a silver imaged lithographic printing plate.

The silver-imaged lithographic printing plate used in the present invention is described, for example, in US Pat. No. 2,352,014 and A.
The book "Photographic Silver Ha" by ndre Rott and Edith Weyde.
“Lide Diffusion Processes”
-The Focal Press- Londona
It is preferably manufactured according to the principle of a silver complex diffusion transfer reversal method described in the New York, (1972), hereinafter referred to as a DTR method.

In the DTR-method, (in
converting the undeveloped silver halide of the exposed photographic silver halide emulsion layer material into a soluble silver complex compound with a so-called silver halide solvent, diffusing the soluble silver complex compound into the image receiving element; Thus, a silver image ("DT") generally reduced by a developing agent in the presence of physical development nuclei and having an image density value inverted from the black silver image obtained in the exposed area of the photographic material
An R-image ") is formed.

The DTR-image bearing material can be used as a lithographic printing plate wherein the DTR-silver image areas form a water repellent ink receptive area on a water receptive ink repellent background.

DTR-images can be formed in an image receiving layer of a sheet or web material which is a separate element to the photographic silver halide emulsion material (the so-called two-sheet DT).
R element), or a so-called single-support-el element, also called a mono-sheet element.
and a single support element comprising at least one photographic silver halide emulsion layer in water-permeable relationship with the image-receiving layer and integral with the image-receiving layer. The latter mono-sheet version is preferred for producing offset printing plates by the DTR method.

There are two types of monosheet DTR offset printing plates. For example, U.S. Pat.
According to the first type disclosed in U.S. Pat. No. 535 and British Patent No. 1,241,661, the physical order acting as a silver halide emulsion layer and an image receiving layer in water permeable relationship with said emulsion layer in the order described. There is provided an imaging element comprising a support with a layer containing the target development nuclei. After informed exposure and development, the imaged element is used as a printing plate without removing the emulsion layer. Layers in water-permeable contact with each other are layers that are in contact with each other or only separated from each other by one or more water-permeable layers. The properties of the water-permeable layer can be determined by the diffusion of water or the compounds contained in the aqueous solution, such as developing agents.
ts) or a property that does not substantially suppress or limit the diffusion of complexed silver ions.

Supports suitable for use in the imaging element can be opaque or transparent, for example, a paper support or a resin support. If a paper support is used, preference is given to supports coated on one or both sides with an α-olefin polymer, for example a polyethylene layer which may optionally contain an antihalation dye or pigment. Organic resin support, for example, cellulose nitrate film, cellulose acetate film, poly (vinyl acetal) film, polystyrene film, poly (ethylene terephthalate) film, polycarbonate film, polyvinyl chloride film, or poly α-olefin film, for example, polyethylene Alternatively, it is also possible to use a polypropylene film. The thickness of such an organic resin film is preferably from 0.07 to
0.35 mm. These organic resin supports are preferably coated with a hydrophilic adhesive layer which may contain water-insoluble particles such as silica or titanium dioxide. Metal supports, for example aluminum, can also be used.

The photographic silver halide emulsion is, for example, “C
himie et Physique Phtogra
phique ", Paul Montel, Paris
(1967). Described by Glafkids, and "Photographic Emulsi
on Chemistry ", The FocalPr
ESS, London (1966). F.
Duffin, and "Making a
nd Coating Phthographic Em
ulsion ", The Focal Press,
London (1966). L. Zeli
It can be prepared from a soluble silver salt and a soluble halide according to various methods as described by Kman et al.

According to the invention, the emulsion or emulsions preferably consist essentially or completely of silver chloride, but have a proportion of 0.1 to 40 mol% of silver bromide. Can be. When the proportion of silver bromide is 5% or more, the emulsion preferably belongs to the core-shell type known to those skilled in the art in that substantially all the bromide is concentrated in the core. . The core preferably contains 10 to 40% of the total precipitated silver halide, while the shell preferably contains 6 to 10% of the total precipitated silver halide.
Consists of 0-90%.

The average size of the silver halide grains is from 0.10 to 0.70 μm, preferably from 0.2 to 0.70 μm.
It can be in the range of 5-0.45 μm.

Preferably, iridium and / or rhodium containing compounds or a mixture of both are added during the precipitation step. The concentration of these added compounds was AgNO ₃ 1
10 ^-8 to 10 ^-3 mol per mol, preferably AgNO
₃ Within the range of 0.5 * 10 ^-7 to 10 ^-5 mol per mol.

Emulsions can be chemically sensitized, for example, by adding a sulfur-containing compound, such as allyl isothiocyanate, allyl thiourea, and sodium thiosulfate during the chemical ripening step. A reducing agent such as BE-
The tin compounds and polyamines described in P 493,464 and 568,687 can be used as chemical sensitizers, for example derivatives of diethylenetriamine or aminomethanesulfonic acid. Other suitable chemical sensitizers are noble metals and noble metal compounds such as, for example, gold, platinum, palladium, iridium, ruthenium and rhodium. This method of chemical sensitization is described in KOSLOWSKY, Z. Wi
ss. Photogr. Photophys. Photo
ochem. 46, 65-72 (1951).

The silver halide emulsion of the DTR element can be spectrally sensitized according to the spectral emission of an exposure light source. This exposure light source is the exposure light source for which the DTR element is designed.

Suitable sensitizing dyes for the visible region of the spectrum include methine dyes such as "The Cyanin"
e Dyes and Related Compou
nds ", 1964, John Wiley & So
ns at F.S. M. Included are the methine dyes described by Hamer. Dyes that can be used for this purpose include:
Cyanine dye, merocyanine dye, complex
x) cyanine dyes, complex merocyanine dyes, monopolar (ho)
mopolar) cyanine dyes, hemicyanine dyes, styryl dyes and hemioxonol dyes. Particularly valuable dyes are cyanine dyes, merocyanine dyes,
It is a dye belonging to the complex merocyanine dye.

In the case of an ordinary light source, for example, tungsten light, a green sensitizing dye is required. In the case of exposure with an argon ion laser, a blue sensitizing dye is blended. In the case of exposure with a red light emitting source, for example an LED or HeNe laser, a red sensitizing dye is used.
In the case of exposure with a semiconductor laser, a special spectral sensitizing dye suitable for near infrared rays is required. Suitable infrared sensitizing dyes are described, for example, in US Pat. No. 2,095,
No. 854, U.S. Pat. Nos. 2,095,856, 2,9
No. 55,939, No. 3,482,978, No. 3,55
No. 2,974, No. 3,573,921, No. 3,58
No. 2,344, No. 3,623,881 and No. 3,69
No. 5,888.

The preferred blue sensitizing dye, green sensitizing dye, red sensitizing dye and infrared sensitizing dye for the present invention are EP-A
554,585.

In order to increase the sensitivity in the red or near-infrared region, so-called supersensitizers in combination with red or infrared sensitizing dyes can be used. Suitable supersensitizers are Research
Disclosure Vol 289, May 1
988, item 28952. The spectral sensitizer can be added to the photographic emulsion in the form of an aqueous solution, an organic solvent solution or a dispersion.

The silver halide emulsion can contain usual emulsion stabilizers. Suitable emulsion stabilizers are azaindenes, preferably tetra- or pentaazaindenes, especially those substituted by hydroxy or amino groups. Compounds of this type are described in Z. Wiss. Pho
togr. Photophys. Photochem.
47, 2-27 (1952). Other suitable emulsion stabilizers are, inter alia, heterocyclic mercapto compounds.

The silver halide emulsion can contain a pH adjusting component. Preferably, the emulsion layer is coated at a pH value near the isoelectric point of gelatin to improve the stability properties of the coated layer. Other ingredients such as antifoggants, development accelerators, wetting agents and hardeners for gelatin may be present. The silver halide emulsion layer is a light-blocking dye (light) that absorbs scattered light and thus enhances image sharpness.
-Screening days). Suitable light absorbing dyes are, inter alia, U.S. Pat.
No. 092,168, U.S. Pat. No. 4,311,787 and DE-P 2,453,217.

Further details on the composition, preparation and coating of silver halide emulsions can be found, for example, in Produc
t Licensing Index, Vol. 92,
December 1971, publication
9232, p. 107-109.

The layer containing the physical development nuclei may be free of a hydrophilic binder, but preferably comprises, for example, up to 80% by weight of the total weight of the layer of a hydrophilic colloid, for example polyvinyl alcohol. To improve the hydrophilicity of the surface.
Preferred development nuclei for use in accordance with the present invention are sulphides of heavy metals, for example sulphides of antimony, bismuth, cadmium, cobalt, lead, nickel, palladium, platinum, silver and zinc. Particularly preferred development nuclei for the present invention are
It is a palladium sulfide nucleus. Other suitable development nuclei are, for example, heavy metal salts such as selenides, polyselenides, polysulfides, mercaptans, and tin (II) halides. Heavy metals, preferably silver, gold, platinum, palladium and mercury, can be used in colloidal form.

Between the support and the silver halide emulsion layer,
Image-wise exposure of the imaging element
It is preferred to provide a base layer which preferably contains an antihalation material, such as a light absorbing dye, which absorbs the light used in the xposure. Alternatively, finely divided carbon black can be used as an antihalation material. On the other hand, in order to increase the photosensitivity, light reflective pigments,
For example, titanium dioxide can be present in the base layer. In addition, this layer may contain hardeners, matting agents, such as silica particles and wetting agents. Suitable matting agents are
Preferably, it is 2 to 10 μm, more preferably, 2 μm to 5
It has an average diameter of μm. Matting agents, the total amount of general imaging element in is used in a ^{0.1g / m 2 ~2.5g / m 2} . At least a portion of these matting agents and / or light-reflective pigments are present in the silver halide emulsion layer and in the cover layer (cover).
(layer). In still another embodiment, the light-reflective pigment may be present in another layer provided between the antihalation layer and the photosensitive silver halide emulsion layer. Like the emulsion layer, the base layer is preferably coated at a pH value near the isoelectric point of the gelatin in the base layer.

In a preferred embodiment of this embodiment,
A backing layer is provided on the non-photosensitive side of the support. This layer, which can serve as an anti-curl layer, may include, inter alia, matting agents such as silica particles, lubricants, antistatic agents, light absorbing dyes, opacifying agents such as titanium oxide, and hardeners and wetting agents. Ordinary components such as The backing layer can consist of one single layer or double layer pack.

The hydrophilic layer usually contains gelatin as a hydrophilic colloid binder. Mixtures of different gelatins with different viscosities can be used to adjust the rheological properties of the layers. Like the emulsion layer, the other hydrophilic layer is preferably coated at a pH value near the isoelectric point of gelatin. However, instead of or together with gelatin, one or more other natural and / or
Alternatively, synthetic hydrophilic colloids such as albumin, casein, zein, polyvinyl alcohol, alginic acid or a salt thereof, cellulose derivatives such as carboxymethylcellulose, modified gelatin such as phthaloyl gelatin, and the like can be used.

The hydrophilic layer of the photographic element may contain a suitable hardening agent, for example, a vinyl sulfone type hardening agent, such as methylene bis (sulfonylethylene), aldehyde, especially when the binder used is gelatin. For example, formaldehyde, glyoxal, and glutaraldehyde,
N-methylol compounds, such as dimethylol urea, and methylol dimethylhydantoin, active hydrogen compounds,
For example, it can be hardened with 2,4-dichloro-6-hydroxy-s-triazine, mucohalic acid such as mucochloric acid and mucophenoxycyclolic acid. These hardeners can be used alone or in combination. The binder can also be hardened with a fast-acting hardener such as a carbamoylpyridinium salt of the type described in U.S. Pat. No. 4,063,952.

Preferably, the hardener used is of the aldehyde type. Hardeners can be used in a wide concentration range, but preferably from 4% of the hydrophilic colloid
Used in an amount of 7%. Different amounts of hardener can be used in different layers of the imaging element, or hardening of one layer can be adjusted by diffusion of the hardener from another layer.

The imaging element used according to this embodiment may further comprise various types of surfactants in the photographic emulsion layer or in at least one other hydrophilic colloid layer. Examples of suitable surfactants are, for example, EP
545452. Preferably, compounds containing a perfluorinated alkyl group are used.

The photographic material of this embodiment further comprises various other additives such as, for example, compounds that improve the dimensional stability of the photographic element, UV absorbers, spacing agents and plasticizers. Can consist of

Suitable additives for improving the dimensional stability of the photographic element are, for example, water-soluble or poorly soluble synthetic polymers such as, for example, alkyl (meth) acrylates, alkoxy (meth) acrylates, glycidyl (meth) acrylates , (Meth) acrylamide, vinyl ester,
Polymers of acrylonitrile, olefin, and styrene, or these, and acrylic acid, methacrylic acid,
It is a dispersion of a copolymer of α-β-unsaturated dicarboxylic acid, hydroxyalkyl (meth) acrylate, sulfoalkyl (meth) acrylate and styrene sulfonic acid.

The imaging element can be exposed in an informed manner in an apparatus according to the particular application. Cameras for exposing the photosensitive silver halide emulsion are widely available on the market. Horizontal, vertical and darkroom type camera and contact exposure device,
It is available for convenience in any particular type of reprographic work. The imaging element may include (i.
a) Exposure can also be performed using a laser recorder and a cathode ray tube.

The alkaline processing liquid used to develop the imaging element according to the DTR method preferably contains a silver halide solvent. Preferably, the silver halide solvent is used in an amount of 0.01% to 10% by weight, more preferably 0.05% to 8% by weight. Suitable silver halide solvents for use in connection with the present invention are, for example, 2-mercaptobenzoic acid, cyclic imides, oxazolidones and thiosulfates. Silver halide solvents which are preferably used in connection with the present invention are thiocyanates and alkanolamines.

Suitable alkanolamines for use in connection with the present invention can be tertiary, secondary or primary. Examples of alkanolamines that can be used in connection with the present invention have the formula:

[0066]

Embedded image

In the formula, X and X 'independently represent hydrogen, a hydroxyl group or an amino group, 1 and m each represent an integer of 0 or 1 or more, and n represents an integer of 1 or more. , Equivalent to Alkanolamines preferably used include, for example, N- (2-aminoethyl) ethanolamine, diethanolamine, N-methylethanolamine, triethanolamine, N-ethyldiethanolamine, diisopropanolamine, ethanolamine, 4-aminobutanol, N, N-dimethylethanolamine, 3-aminopropanol, N, N-ethyl-2,2'-iminodiethanol and the like or a mixture thereof.

According to the invention, the alkanolamine is preferably present in an alkaline processing liquid. However, some or all of the alkanolamine can be present in one or more layers of the imaging element.

A further preferred class of silver halide solvents are thioether compounds. Preferably, in a thioether used has the general formula _{^{Z- (R 1 -S) t -R}} 2 -S-R 3 -Y formula, Z and Y are each independently hydrogen, an alkyl group, an amino group , an ammonium group, a hydroxyl, a sulfo group, a carboxyl, an aminocarbonyl or an aminosulfonyl, R ^1, R ² and R ³ each independently represents an alkylene, the alkylene is oxygen bridge well and optionally also be substituted And t represents an integer from 0 to 10. Examples of thioether compounds corresponding to the above formula are disclosed, for example, in U.S. Pat. No. 4,960,683 and EP-A 547,662. Accordingly, they are incorporated herein by reference.

[0070] Still other suitable silver halide solvents are mesoionic compounds. Preferred mesoionic compounds for use in connection with the present invention are triazolium thiolates, more preferably 1,2,4-triazolium-
3-thiolates.

Preferably, at least a portion of the mesoionic compound, more preferably all of the mesoionic compound,
Present in the alkaline processing liquid used to develop the image-wise exposed imaging element. Preferably, the amount of the mesoionic compound in the alkaline treatment liquid is between 0.1 mmol / l and 25 mmol / l, preferably between 0.1 and 25 mmol / l.
5 mmol / l to 15 mmol / l, most preferably
It is 1 mmol / l to 8 mmol / l.

However, the mesoionic compound can be included in one or more layers provided on the support of the imaging element. In that case, the mesoionic compound is 0.1 to 10 mmol / m ² , more preferably 0.1 to 5 mmol / m ² , most preferably 0.5 to 5 mmol / m ² .
Preferably, a total amount of 1.5 mmol / m ² is included in the imaging element. For further details see EP-A-0,554,58
5 is disclosed.

The alkaline processing liquid used according to the invention preferably has a pH of 9 to 14, more preferably a pH of 10 to 13. The pH is determined by an organic or inorganic alkaline substance or a combination thereof.
Suitable inorganic alkaline substances are, for example, potassium or sodium hydroxide, potassium or sodium carbonate, potassium or sodium phosphate and the like. Suitable organic alkaline substances are, for example, alkanolamines. In the latter case, the alkanolamine will help provide or maintain the above-mentioned pH and will act as a silver halide complexing agent.

The alkaline processing liquid may also contain one or more than one developing agent. In this case, the alkaline processing liquid is called a developer. On the other hand, some or all of one or more developing agents can be present in one or more layers of a photographic material or imaging element. When all of the developing agents are included in the imaging element, the alkaline processing liquid is called an activator or activating liquid.

The silver halide developing agents used according to the invention are preferably of the p-dihydroxybenzene type, for example hydroquinone, methylhydroquinone or chlorohydroquinone, which are 1-phenyl-3
An auxiliary developing agent which is a pyrazolidone type developing agent and / or p-monomethylaminophenol (auxiliar)
It is preferable to use a combination with (y developing agent). One particularly useful auxiliary developing agent is 1
-Phenyl-3-pyrazolidones. Especially when they are included in photographic materials, the water solubility of 1-phenyl-3-pyrazolidone is increased by hydrophilic substituents such as, for example, hydroxy, amino, carboxylic acid groups, sulfonic acid groups and the like. 1-phenyl-3-pyrazolidones are more preferred. Examples of 1-phenyl-3-pyrazolidones substituted with one or more hydrophilic groups include, for example, 1-phenyl-4,4-dimethyl-2-hydroxy-3-pyrazolidone, 1- (4 -Carboxyphenyl)
-4,4-dimethyl-3-pyrazolidone and the like. However, other developing agents can be used.

At least an auxiliary developing agent is used in the photographic material, preferably in the silver halide emulsion layer of the photographic material.
150 m / g of silver halide expressed as gNO ₃
g or less, more preferably 100 mg or less per gram of silver halide expressed as AgNO ₃ .

The alkaline processing liquid used for developing the above-described image forming element preferably also contains a hydrophobizing agent for improving the hydrophobicity of the silver image obtained in the image receiving layer. The hydrophobizing agents used in connection with the present invention are compounds which can react with silver or silver ions and are hydrophobic, ie insoluble or only slightly soluble in water. Generally, these compounds contain a mercapto or thiolate group and one or more hydrophobic substituents, for example, an alkyl group containing at least 3 carbon atoms. Examples of hydrophobizing agents used in connection with the present invention are described in U.S. Pat. No. 3,776,728 and U.S. Pat.
No. 410, a hydrophobizing agent. Preferred compounds are of the formula

[0078]

Embedded image

[0079] In the formula, R ⁵ represents hydrogen or an acyl group, R ⁴
Represents alkyl, aryl or aralkyl. Most preferably used compounds are those wherein R ⁴ is 3
A compound according to one of the above formulas representing an alkyl containing １６16 carbon atoms.

According to the invention, the hydrophobizing agent is at least 0.1 g / l, more preferably at least 0.2 g / l
1, most preferably at least 0.3 g / l in the alkaline processing liquid. The maximum amount of hydrophobizing agent will be determined by the type of hydrophobizing agent, the type and amount of silver halide solvent, and the like. Typically, the concentration of the hydrophobizing agent is preferably 1.5 g / l or less, more preferably 1 g / l or less.

The alkaline processing liquid is preferably a preserving agent having an antioxidant activity.
t) also contains sulphite ions, for example provided by sodium or potassium sulphite. For example, the aqueous alkaline solution comprises sodium sulfite in an amount ranging from 0.15 to 1.0 g / l. Further, a thickener (thick)
ening agents, such as hydroxyethylcellulose and carboxymethylcellulose; antifoggants such as potassium bromide, potassium iodide and benzotriazoles, which are known to improve print durability, calcium ion sequestering compounds (calcium-s).
equaling compounds), anti-sludge agents
And hardeners, including latent image hardeners. According to the present invention, it is even more preferred to use a spreading agent or a surfactant during the alkaline processing to ensure even spreading of the alkaline processing solution on the surface of the photographic material. Such surfactants should be stable at the pH of the alkaline processing liquid and ensure rapid wetting of the entire surface of the photographic material. Surfactants suitable for such purpose are, for example, fluorine-containing surfactants, for example C ₇ F ₁₅ COONH ₄ . Furthermore, it is advantageous to add glycerin to the alkaline processing liquid so as to prevent crystallization of the dissolved components of the alkaline processing liquid.

Development acceleration can be achieved by adding various compounds to one or more layers of the alkaline processing solution and / or photographic element,
Preferably, for example, US Pat. No. 3,038,805,
This is achieved by adding a polyalkylene derivative having a molecular weight of at least 400, such as the compounds described in 4,038,075, 4,292,400 and 4,975,354.

After development in an alkaline processing liquid according to the invention, the surface of the printing plate is preferably neutralized using a neutralizing liquid.

The neutralization solution generally has a pH of 5-8.
The neutralizing solution preferably contains, for example, a phosphate buffer, a citrate buffer or a mixture thereof. The neutralization solution is
In addition, bactericides, substances which affect the hydrophobic / hydrophilic balance of the printing plate obtained after processing of the DTR element,
For example, it may include hydrophobizing agents, silica and wetting agents as described above, preferably compounds containing perfluorinated alkyl groups.

A lithographic printing plate is thus obtained.

According to another embodiment, in the stated order, by the DTR method using an imaging element comprising a hydrophilic surface of a support, a layer containing physical development nuclei and a silver halide emulsion layer. A lithographic printing plate can be obtained.

The hydrophilic surface of the support can be a hardened hydrophilic layer containing a hydrophilic binder and a hardener coated on a flexible support.

Such a hydrophilic binder is, for example, EP-
A 450,199, which is hereby incorporated by reference. Preferred hardened hydrophilic layers are partially modified dextran or e.g. EP
-Comprising pullulan cured with an aldehyde as disclosed in A514,990. EP-A514,99
0 is hereby incorporated by reference. A more preferred hydrophilic layer is a layer of polyvinyl alcohol preferably containing SiO ₂ and / or TiO ₂ hardened with tetraalkyl orthosilicate, wherein the weight ratio of the polyvinyl alcohol to the tetraalkyl orthosilicate is 0.
5 to 5 are layers of polyvinyl alcohol. These layers are described, for example, in British Patent No. 1,419,512, French Patent No. 2,300,354, U.S. Pat.
No. 1,660, U.S. Pat. No. 4,284,705, EP
-A405,016 and EP-A450,199. Accordingly, they are incorporated herein by reference.

[0099] Flexible supports, such as paper supports or resin supports, are described above.

The hydrophilic surface of the support can be a hydrophilic metal support, for example, an aluminum foil.

The aluminum support of the imaging element for use in accordance with the present invention can be made from pure aluminum or an aluminum alloy having an aluminum content of at least 95%. The thickness of the support is usually about 0.
It ranges from 13 mm to about 0.50 mm.

The production of aluminum or aluminum alloy foil for lithographic offset printing comprises the following steps:
That includes polishing, anodizing and optional foil sealing.

[0093] Polishing and anodizing of the foil is necessary to obtain a lithographic printing plate capable of producing high quality printed matter. Sealing is not required, but can still improve the printing results. Preferably, the aluminum foil has a roughness with a CLA value of 0.2-1.5 μm,
An anodic oxide layer having a thickness of 0.4 to 2.0 μm,
Then sealed with aqueous bicarbonate solution. Polished,
Further details regarding the production of anodized and sealed aluminum foils can be found in US Pat. No. 3,861,9.
No. 17 and the references cited therein.

To enhance the sharpness of the image and consequently the sharpness of the final printed copy, the anodized layer is generally coated with an antihalation dye or pigment as described in JA-Pu 58-14797. Can be colored.

As a binder in one or more silver halide emulsion layers according to the present invention, a hydrophilic colloid, usually a protein, preferably gelatin, can be used. However, gelatin can be partially or completely replaced by synthetic, semi-synthetic or natural polymers. Preferably, the silver halide emulsion layer is at least one gelatin species whose 10% by weight aqueous solution is 20 mP at 36 ° C. and pH 6 at a shear rate of 1000 s ^−1.
A gelatin species having a lower viscosity than as is contained in combination with a gelatin having a higher viscosity. The weight ratio of said low viscosity gelatin to high viscosity gelatin is preferably>
0.5.

Preferably, the one or more gelatin layers are substantially uncured. Substantially uncured means that such a gelatin layer is coated on a primed polyethylene terephthalate film base at a dry thickness of 1.2 g / m ² and at 57 ° C. and 35%
R. H. Means that the gelatin layer dissolves more than 95% by weight within 5 minutes when dried in water at 30 ° C. for 3 days.

The imaging element of this embodiment is subjected to camera exposure or scanning exposure as described above and then in the presence of one or more developing agents and one or more silver halide solvents. An image can be formed by subjecting the silver image to a physical development nucleus layer by subjecting it to a development step. The silver halide emulsion layer and other optional hydrophilic layers are then
The imaged element is removed, preferably by washing with water at 30 ° C. to 50 ° C., thereby exposing the silver image.

To facilitate removal of the silver halide emulsion layer, a hydrophilic non-protein film forming polymer such as polyvinyl alcohol, polymer beads such as poly (meth) acrylate beads, a number average size of 0.1 μm or more (number) particles of a water-insoluble inorganic compound having an average size, an alkali-insoluble non-polymeric organic compound having a melting point of at least 50 ° C. and a number average size of 0.1 μm to 10 μm;
It is advantageous to provide a layer comprising particles of an alkali-insoluble polymer obtainable by polycondensation having a number average size of 10 μm between the layer containing physical development nuclei and the silver halide emulsion layer. This type of layer is called E
P-A-483415, EP-A-410500, EP
-A-94203779.7, EP-A-952017
13.5 and EP-A-95203052.6.

Finally, the exposed and imaged surface of the hydrophilic support is treated with a finisher to increase the water receptivity of the non-image areas and render the image areas oleophilic ink receptive.

Lithographic compositions, often referred to as finishes, comprise at least one compound that enhances the ink receptivity and / or lacquer receptivity of the silver image and at least one compound that improves the ink repellency of the hydrophilic surface. Comprising.

Suitable ingredients for finishes are, for example,
Organic compounds containing a mercapto group, such as the hydrophobizing compounds described above for alkaline solutions. One or one
More than one such hydrophobizing agent is present in the finish at 0.1 g /
l to 10 g / l, more preferably 0.3 g / l
It is contained at a total concentration of 1-3 g / l.

Additives which improve the lipophilic ink repellency of the hydrophilic surface areas are, for example, carbohydrates, such as acidic polysaccharides, such as gum arabic, carboxymethylcellulose, sodium alginate, propylene glycol esters of alginic acid, hydroxyethyl starch. Dextrin, hydroxyethylcellulose, polyvinylpyrrolidone, polystyrenesulfonic acid, and polyvinyl alcohol, preferably polyglycol which is a reaction product of ethylene oxide and / or propylene oxide with water or alcohol. Optionally, hygroscopic materials can be added, such as sorbitol, glycerol, tri (hydroxyethyl) ester of glycerol, and sulfated castor oil.

Thus, a lithographic plate is obtained.

The following examples illustrate the invention.
The present invention is not limited to these examples. All parts are by weight unless otherwise specified.

[0105]

【Example】

Example 1 Preparation of a silver halide emulsion coating solution A silver chlorobromide emulsion composed of 98.2 mol% of chloride and 1.8 mol% of bromide was prepared by a double jet precipitation method (doub).
le jet precipitationmethod
d). The average silver halide grain size was 0.4 μm (diameter of a sphere with equivalent volume) and contained rhodium ions as internal dopant. 4-hydroxy-
6-Methyl-1,3,3a, 7-tetraazaindene was added as stabilizer in an amount of 290 mg per mole of silver halide, and prior to coating, the emulsion was orthochromatically added by adding a green sensitizing dye. Was sensitized to A base layer coating solution having the following composition was prepared.

Gelatin 5.5% Carbon black 0.76% Silica particles (5 μm) 1.6% Preparation of lithographic printing plate with silver image Emulsion coating solution and base layer coating solution were slide hopper coated on polyethylene terephthalate support Coated simultaneously by law. The emulsion layer has a silver halide coverage (c expressed as AgNO ₃ )
average) was 1.5 g / m ² and the gelatin content was 1.5 g / m ² .
The emulsion layer further contained 0.15 g / m ² of 1-phenyl-4,
4'-dimethyl-3-pyrazolidone, 0.25 g / m ²
Of hydroquinone and 100 mg / m ² of formaldehyde. The base layer was coated such that the transmission density of the packet between the support and the base layer was 0.65.

The element thus obtained was dried and dried.
Exposure to a temperature of 40 ° C. for a day, then the emulsion layer was overcoated with a layer containing PdS as a physical development nucleus and containing 0.4 g / m ² of hydroquinone and 100 mg / m ² of formaldehyde.

The following processing solutions were prepared.

Activator sodium hydroxide 30 g sodium sulfite anhydride 35 g 2-aminoethyl-aminoethanol 20 ml 1-methyl-4-allyl-5-methyl-1,2,4-triazolium-3-thiolate 1.1 g 2- Mercapto-5-n. Heptyl-oxa 3,4-diazole 150 mg Water 1 L Amount of neutralized solution NaH ₂ PO ₄ . 2H ₂ O 40 g Nonionic surfactant 200 mg Compound A ^a) 800 mg Triethanolamine 10 ml Sodium benzoate 1 g Sodium sulfite 4 g Turpinal (Turpinal) 2NZ ^b) 1 g Sodium ethylenediaminetetraacetate 1 g Water 1 l Amount Compound A) is a mercaptotetrazole substituted with _{-CH 2 CON (n.C 4 H 9} ) 2 by the 1-position.

B) Terpinal 2NZ is the trade name of Henkel, Belgium for bis-disodium phosphonate (1-hydroxyethylidene) salt.

The unexposed imaging element is treated with the above activator at 30 ° C. for 2 seconds, and then treated with the above neutralizing solution for 25 seconds.
Neutralized at <RTIgt; C, </ RTI> dried and then divided into 30 samples of the silver imaged lithographic printing plate.

Ten correction fluids having the same composition except for the accelerator were prepared. The common composition of the correction fluid was as follows.

Sodium sulfite 25 g / l sodium EDTA ^a) 25 g / l citric acid 11 g / l sodium hydroxide 2 g / l ammonium thiosulfate 250 g / l Ambiteric H (C ₁₆ H ₃₃ N ⁺ (CH ₃ ) ₂ CH ₂ COO ⁻ ) 1 g / l EDTA iron (III) ammonium ^a) 81 g / l accelerator 0.125 mol / l adjusted to the right pH with sodium hydroxide 7.1 a) EDTA stands for ethylenediaminetetraacetic acid.

A lithographic printing plate with a silver image was placed in each of the correction fluids. The effectiveness of the ten correction solutions was represented by the following parameters.

-T50%: The transmission density is 50% of the original value.
-Time required to completely remove the silver image;-% 30 s: percentage reduction in transmission density after 30 seconds of treatment in correction solution, results tabulated. It is shown in FIG.

[0116]

[Table 2]

A) Formulas of compounds 1 to 3 are shown in Table 1, and formulas of compounds 4 to 10 are shown in Table 3.

[0118]

[Table 3]

The correction solutions comprising compounds 1 to 3 (correction solutions according to the invention) are very effective,
It is clear that correction fluids comprising (comparative correction fluids) have very low effectiveness.

Example 2 Four correction fluids having the same composition except for the amount of sodium sulfite were prepared. The common composition of the correction fluid was as follows.

Sodium EDTA ^a) 25 g / l sulfuric acid (6N) 60 ml / l ammonia (33%) 26 ml / l ammonium thiosulfate 200 g / L Ambiteric H (C ₁₆ H ₃₃ N ⁺ (CH ₃ ) ₂ CH ₂ COO ⁻ ) 1 g / L EDTA ammonium iron (III) ^a) 81 g / l Compound 3 7.5 g / l pH adjusted to the right 7.5 a) EDTA represents ethylenediaminetetraacetic acid.

Each of the correction solutions was tested as a fresh solution,
Then, the test was carried out after being left in a sealed bottle at 60 ° C. for 3 days. A sample of the lithographic printing plate with the silver image formed was placed in each of the above correction fluids. The effectiveness of the eight correction fluids was measured according to the parameters shown in Example 1. Table 4 shows the results.

[0123]

[Table 4]

These results indicate that the storage stability of the correction fluid is improved when the correction fluid comprises sodium sulfite and that the optimum amount of sodium sulfite is between 10 g / l and 40 g / l. Example 3 Five correction fluids having the same composition except pH were prepared. The common composition of the correction fluid was as follows.

Sodium sulfite 25 g / l Ammonium thiosulfate 240 g / L Ambiteric H (C ₁₆ H ₃₃ N ⁺ (CH ₃ ) ₂ CH ₂ COO ⁻ ) 1 g / L EDTA iron (III) ammonium ^a) 81 g / l Compound 3 7. 5 g / l pH was adjusted to the value shown in Table 5 with 6N sulfuric acid or 33% ammonia.

A) EDTA stands for ethylenediaminetetraacetic acid.

Each of the correction solutions was tested as a fresh solution,
Then, the test was carried out after being left in a sealed bottle at 60 ° C. for 3 days. A sample of the lithographic printing plate with the silver image formed was placed in each of the above correction fluids. The effectiveness of the eight correction fluids was measured according to the parameters shown in Example 1. Table 5 shows the results.

[0128]

[Table 5]

A correction fluid having a pH higher than 9 has a lower efficacy and a correction fluid having a pH of 5 is not stable on storage (both comparative correction fluids) but has a pH of 6, 7 and 8. The correction fluid is a very effective correction fluid whether used fresh or after standing at 60 ° C. for 3 days (correction fluid according to the invention).

The main features and aspects of the present invention are as follows.

1. An aqueous solution having a pH in the range of 5.5 to 8.5, comprising an iron (III) complex salt of an organic acid, a sulfite or metabisulfite, a silver halide solvent, and an accelerator. A correction liquid for a silver-imaged lithographic printing plate, wherein the accelerator is an organic heterocyclic compound having a mercapto group or a thione group and having no hydrophilic substituent other than the mercapto group or a thione group. 5. The correction liquid for a lithographic printing plate having a silver image formed thereon, wherein the accelerator is present in an amount in the range of 0.04 to 0.4 mol per liter of the correction liquid.

[0132] 2. 2. The correction solution for a silver-image-formed lithographic printing plate according to claim 1, wherein the accelerator contains at least two nitrogen atoms in a heterocyclic group.

3. The above-mentioned 1 wherein the accelerator is used in an amount in the range of 0.08 to 0.2 mol per liter of correction fluid.
Or the correction liquid for a lithographic printing plate having a silver image formed thereon according to 2.

4. The iron (III) complex salt of the organic acid is an aminopolycarboxylic acid or a phosphonic acid or an iron (II) salt of the acid.
I) The correction liquid for a lithographic printing plate according to any one of the above items 1 to 3, which is a complex salt.

[0135] 5. 5. The correction solution for a lithographic printing plate having a silver image formed thereon as described in 4 above, wherein the aminopolycarboxylic acid or a salt thereof is ethylenediaminetetraacetic acid (EDTA) or a salt thereof.

6. Correction solution 1
The correction solution for a lithographic printing plate having a silver image formed thereon according to any one of the above items 1 to 5, which is used in an amount of 0.07 to 0.7 mol per liter.

7. 5. The silver-imaged lithographic printing plate of claim 4, wherein the correction fluid contains an extra amount of aminopolycarboxylic acid or phosphonic acid in the range of 0.02 to 0.2 mole per liter of the correction fluid. Correction fluid.

8. Either the sulfite is present in the correction fluid in an amount within the range of 0.06-0.6 mole per liter of correction fluid, or metabisulfite is present in an amount of 0.03-0.3 mole per liter of correction fluid. 8. The correction liquid for a lithographic printing plate having a silver image formed thereon according to any one of the above 1 to 7, which is present in the correction liquid in an amount in a range.

9. 9. The correction solution for a silver image-formed lithographic printing plate according to any one of the above 1 to 8, wherein the thiosulfate is present in the correction solution in an amount within the range of 0.5 to 5.0 mol per liter of the correction solution. .

10. 10. The correction liquid for a lithographic printing plate having a silver image formed thereon according to any one of the above 1 to 9, wherein the correction liquid comprises a surfactant.

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁶ , DB name) G03F 7 / 40,7 / 07,7 / 00

Claims (1)

(57) [Claims] 1. An iron (III) complex salt of an organic acid and a correction liquid 1.
An amount in the range of 0.06 to 0.6 moles per liter 0.03 to 0.3 moles per liter of rectifying fluid.
A metabisulfite within the range of
An aqueous solution having a pH in the range of 5.5 to 8.5 comprising an accelerator, wherein the accelerator has a mercapto or thione group and is hydrophilic in addition to the mercapto or thione group. met lithographic printing plate correction fluid formed silver image is an organic heterocyclic compound having no substituent, within the promoter correction fluid 0.04 to 0.4 moles per liter A correcting solution for a lithographic printing plate having a silver image formed, wherein the correcting solution is present in an amount.