JP3135736B2 - Lithographic printing plate processing solution processing method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for preparing a printing plate by supplying an alkaline processing solution to an image-formed lithographic printing plate to dissolve the non-image portion and then removing the non-image portion components from the printing plate. The present invention relates to a method for treating a processing fatigue alkaline treatment liquid accompanying the treatment, and more particularly to a method for treating a lithographic printing plate treatment liquid, which can easily carry out treatment when discarding a highly alkaline treatment liquid and reduces a treatment waste liquid treatment load.

[0002]

2. Description of the Related Art A non-image area alkali dissolving lithographic printing plate contains, on a hydrophilic support, at least an actinic ray-inducing treatment liquid solubilizing substance or an actinic ray curable substance accompanied by a change in chemical structure due to actinic rays. A photosensitive lithographic printing plate (so-called PS plate) provided with a photosensitive layer to be formed is known, and is widely used for heavy printing requiring high printing durability. These are prepared by exposing a silver halide photographic film master on which an image has been recorded in advance to a printing plate photosensitive surface in close contact with the printing plate, thereby allowing a hardened portion corresponding to an image portion or a processing solution corresponding to a non-image portion in a final print. A solubilized portion is formed, and a non-image portion is dissolved and removed with an alkaline processing solution.

Also, an electrophotographic lithographic printing plate for forming an image by using an electrophotographic technique is known, and a printing plate corresponding to scanning exposure is also manufactured. The non-image area alkali-removal type lithographic printing plate utilizing electrophotographic technology is generally provided with an ink-receiving photoconductive layer in which an organic photoconductive substance is dispersed in a resin on a hydrophilic support, and the electrophotographic printing is performed by electrophotography. After a toner image is formed on the photoconductive layer by the method, the non-image portion is eluted with an eluent comprising an alkaline agent using the toner as a resist, and used as a printing plate.

[0004] The plate making process of the non-image area alkali-eluting lithographic printing plate is generally performed by using an automatic machine which supplies and processes a processing solution while automatically transporting the printing plate.
As a processing method adopted in the automatic machine, a liquid circulation reusing method, a new liquid disposable processing method, a liquid remaining in a process process measurement residual liquid, and the like are known.

The liquid circulation recycling method is a method in which an excess amount of a processing liquid is brought into contact with a printing plate, and then the processed liquid is removed from the plate and circulated and reused. Alternatively, besides supplying from a shower or the like, there is a method of immersing a printing plate in a treatment liquid tank in a curved manner (dip method).
The new liquid disposable processing method supplies the new liquid for each plate by pre-measuring the minimum required amount before supplying the processing liquid to the plate surface by adjusting the gap of the liquid supply slit and the wire diameter of the wire bar, etc. In this method, after the treatment promoting means is applied in the course of the treatment, the treated fatigue treatment liquid is removed and discarded together with the solubilized non-image portion. In the process of measuring the residual liquid, the excess liquid is once supplied to the plate surface, the processing liquid is measured to a certain amount during the processing, and the excess liquid is recycled and reused. Is a method of discarding together with the solubilized non-image portion after the development is completed.

The problem common to all of these processing methods is to reduce the maintenance management of the processing liquid and the apparatus such as stabilizing the plate making process, suppressing the generation of the processing waste liquid, and prolonging the liquid exchange cycle. In particular, from the viewpoint of the user, stabilization of the plate making process caused by the apparatus is a major premise, and reduction in maintenance of the processing liquid and the apparatus determines the practical performance of the processing apparatus. In other words, the stabilization of the plate making process is simply the stabilization of the activity of the processing solution. Generally, other than the disposable method, while the components consumed by the process are replenished, the components that become highly concentrated during the process are removed. A means for removing and maintaining the components of the processing solution at a constant level is employed. A replenisher is replenished, part of the processing solution is discarded to remove the highly concentrated components, and the processing performance of the processing solution is reduced. This is because, when the value exceeds the permissible limit and when disposable, the used processing solution is entirely discarded.

[0007] Since the liquid exchange and the cleaning of the processing liquid tank are usually performed manually and periodically, the processing apparatus may be of a structure and a system which can be completed more easily and in a shorter time. Required. In particular, when disposing of the processing waste liquid accompanying the liquid exchange, at least a part of the fatigue processing liquid generated by the plate making process is discarded along with the plate making in order to extend not only the workability but also the processing liquid replacement period. In addition, a method of directly storing in a waste liquid container attached to the apparatus is adopted. In particular, the alkaline processing liquid used for dissolving and removing the non-image area has a considerably high pH, and the processing waste liquid also has a considerable liquid pH. Accordingly, it can be compared with the waste processing method. Even if the processing waste liquid is requested to be treated by a waste liquid processing company, the pH of the liquid must be adjusted within a specific range.

[0008]

SUMMARY OF THE INVENTION The present invention relates to a lithographic printing plate having an image formed thereon, which is supplied with an alkaline processing liquid to dissolve the non-image area and then dissolved in the alkaline processing liquid on the printing plate. The present invention relates to a method for treating a processing fatigue alkaline treatment liquid which is accompanied by plate making processing of a lithographic printing plate for removing a lithographic printing plate. More specifically, a wide range of liquids p
It is an object of the present invention to provide a method for treating a lithographic printing plate, wherein the treatment can be carried out simply in accordance with H and the induction of aggregation is suppressed even after the pH of the solution is lowered.

[0009]

As a result of repeated studies to solve the above problems, an alkaline processing liquid is supplied to the lithographic printing plate on which an image has been formed to dissolve the non-image area, and then the alkaline lithographic printing plate on the lithographic printing plate is dissolved. What is claimed is: 1. A method for treating a lithographic printing plate in which a processing solution and a dissolved non-image portion are removed, the method comprising the steps of: And at least one selected from diammonium carbonate
The present invention has been attained by a method for treating a lithographic printing plate , wherein the treatment solution is discarded after adding the type.

The alkaline processing solution used for dissolving and removing the non-image portion of the non-image portion alkali dissolving and removing type lithographic printing plate generally has a pH of about 13, and the waste solution containing the fatigue treating solution naturally has a considerably high pH. Become. On the other hand, due to the revision of the Waste Disposal and Public Cleansing Law, the pH of such highly alkaline waste liquor must be adjusted to a level below the reference value, regardless of whether the waste is discharged or requested to a waste disposal contractor.

In order to lower the pH of the waste liquid, if the pH of the liquid is lowered at once with a strong acid, rapid heat generation may occur. If the waste liquid container is made of polyethylene or the like,
Thermal deformation may occur. In particular, when an alkali metal silicate represented by the general formula SiO ₂ / M ₂ O is contained as an alkaline agent in the alkaline treatment liquid, the possibility that the entire waste liquid is agglomerated due to a rapid drop in pH is high, and If the pH of the waste liquid condenses in the vicinity of the acid injection part before lowering the pH below the reference value, an operation such as stirring must be added.If sedimentation occurs at the bottom of the waste liquid container, the acid The amount added has to be increased and the final treatment of the waste liquid becomes more complicated.

In this regard, if a specific carbonate is added to a solution containing at least an alkaline treatment solution that has been fatigued by the treatment, the pH of the treatment waste solution can be sufficiently lowered to a reference value or less even in a small amount. Furthermore, even if an alkali metal silicate is contained as an alkaline processing liquid component, the possibility of agglomeration is low. That is, it is generally known that the buffering ability of a compound is the strongest in the acid dissociation constant (pKa) of the compound, but that of carbonate is 6.35 and 10.33, while that of carbonate is alkaline. The pH of the alkali silicate source used in the treatment liquid is higher than 11, and its aggregation is most likely to be near neutral and relatively stable on the high alkali side. Accordingly, in accordance with the pH range of the fatigued alkaline treatment liquid and the type and amount of the alkali species contained therein, the pH of the liquid after the addition of the carbonate is determined from the pH in the aqueous solution of the same concentration of the added carbonate. And a stable mixture is formed over a wide range.

Specific examples of the alkali metal and ammonium salts of hydrogen carbonate and diammonium carbonate relating to the treatment liquid treatment method of the present invention and the method of adding them to the alkaline treatment liquid will be described. Alkali metal bicarbonate and ammonium salt and diammonium carbonate added to a solution containing an alkaline treatment liquid fatigued by at least the treatment according to the present invention (hereinafter referred to as alkali metal bicarbonate and ammonium salt and diammonium carbonate according to the present invention) Are referred to as carbonates according to the present invention.) Include alkali metal hydrogencarbonates such as lysium hydrogencarbonate, sodium hydrogencarbonate and potassium hydrogencarbonate, and ammonium carbonates of ammonium hydrogencarbonate and diammonium carbonate. Can be

[0014] ammonium bicarbonate and carbonate ammonium um of carbonate according to the present invention is preferably, particularly preferable is ammonium bicarbonate. On the other hand, carbonates that are not included in the carbonates according to the present invention, such as disodium carbonate, dipotassium carbonate, calcium carbonate, and magnesium carbonate, themselves have a considerably high pH if they are water-soluble, Almost pH if water (alkali) insoluble
Not suitable because no descent effect can be expected.

These carbonates according to the present invention may be used alone or as a mixture of two or more. These may be added as a solid or as an aqueous solution.

When the carbonate is added to the fatigue alkaline treatment liquid according to the treatment liquid treatment method of the present invention when the fatigue treatment liquid is discarded by liquid exchange or the like, the carbonate may be added to the treatment liquid storage tank. Alternatively, they may be charged into a disposal container before and after transfer from the liquid storage tank to another disposal container, or both may be used in combination. If both are charged, each may be a different type of carbonate. In the case where waste liquid is generated for each plate making by the plate making processing method, the waste liquid may be charged in the waste liquid storage tank in advance, or may be charged during the plate making period and / or after the end (after reaching a constant volume). good. When charging during plate making, it is most preferable to supply an amount corresponding to the amount of waste liquid.

The final pH of the fatigued alkaline treatment liquid according to the present invention after addition of the carbonate must be maintained at less than 12.5. Therefore, the amount of the addition is determined by the alkali strength of the alkaline treatment liquid described below, Liquid p before addition of carbonate
Adjust according to H and its type. The range of the addition amount of the carbonate according to the present invention is optimally the minimum amount at which the pH of both the unused and the fatigued alkaline treatment liquid at the time of disposal is 12.4 or less, more preferably 12.2 or less. pH
For alkaline processing liquids containing components that form aggregates with fluctuations, wash the alkaline processing liquid storage tank.
When the carbonate according to the present invention is added to the waste liquid mixed with the liquid or the like, this is the maximum amount in which the liquid pH becomes 11 or more. The standard of the addition amount of the carbonate according to the present invention is 0.1 to 4% by weight.

Next, the lithographic printing plate making process according to the processing solution processing method of the present invention will be described in detail according to the process. The plate-making processing step according to the processing liquid processing method of the present invention comprises at least an alkaline processing liquid supply step and a non-image area removing / disposing step.

In the alkaline processing liquid supply step, an excessive amount of the alkaline processing liquid is supplied to the image forming surface of the lithographic printing plate on which an image has been formed. As the alkaline processing liquid supply method, a conventionally known mechanism, for example, a shower, a slide hopper, a curtain coater, a dip method, or the like can be used. In particular, when a shower is used, a method in which the liquid discharged from the tube is once rectified through another member, for example, a rectifying plate or an upper roll, and then supplied to the image forming surface is preferable. In addition, in all systems, in order to further shorten the processing time and prevent liquid supply failure, a flow promoting mechanism is provided to replace the alkaline processing liquid supplied on the plate, or to use multiple alkaline processing liquids. It is desirable to supply it over time.

It is important that the minimum supply amount of the alkaline processing liquid is such that the alkaline processing liquid flows down from the edge of the plate during transportation. In other words, a part dissolves the non-image area, and the surplus flows on the plate and flows down from the edge of the plate while partially replacing the existing alkaline processing liquid in the alkali-treated part. Thereby, liquid replacement frequently occurs at the edge of the plate, and the flow rate of the alkaline processing liquid in the vicinity of the interface of the image forming layer increases, thereby suppressing the fluctuation of the solubility in the plate.

The alkaline processing liquid excessively supplied on the printing plate is conveyed to the non-image area removing and discarding step, but all of the alkaline processing liquid on the plate is not consumed in the process of dissolving the non-image area. In addition, in the non-image area removing and discarding step, since all the liquid material on the plate is removed and discarded, the processing liquid supply step is performed before the dissolution of the non-image area image forming layer is completed and the non-image area removing and discarding step is performed. It is preferable to measure and remove at least a certain amount of the alkaline processing liquid on the plate by a liquid measuring means.

When the liquid measurement is performed, the alkaline processing liquid which has not substantially contributed to the dissolution of the image forming layer is removed from the printing plate as much as possible while preventing mixing of the non-image portion dissolved during the liquid measurement. It is important to remove. Therefore, when the amount of the alkaline processing liquid remaining on the plate after the liquid measurement (liquid measurement residual liquid amount) is large, the consumption of the alkaline processing liquid necessarily increases, and the alkaline processing efficiency per unit alkaline processing liquid decreases. In addition, since the dissolution may further progress until the non-image portion removing and discarding step is performed after the liquid measurement and the image is thinned, the residual amount of the alkaline processing liquid measured is preferably smaller.

However, if the residual amount of the alkaline processing solution is too small, the viscosity of the removing solution is significantly increased. As a result, in the continuous plate making, the removing solution accumulates in the non-image area removing and discarding section (member). As a result, the removal effect is reduced, and the possibility that the image forming layer dissolved in the liquid measuring section is peeled increases, which is not preferable. Furthermore, if all the liquid material on the plate is removed in the alkali treatment step as in the liquid circulation system, it is not preferable because the fatigue alkaline treatment solution and the components of the image forming layer are mixed.
The alkaline processing liquid metering residual liquid amount after the liquid metering, depending on whether using any liquid metering means, often 30 to 120 g / m ^2, further preferably from 40 to 100 g / m ^2.

As a liquid measuring tool used in the liquid measuring step,
It can be rotated by any kind of drive transmission in the plate transport direction, makes uniform contact with the plate surface at least in all rotation directions in the measurement width direction, and prevents peeling of the dissolved image forming layer during liquid measurement It is important to have such a shape.
Examples of the liquid measuring tool include a wire bar, a grooved roll, a plain bar, and a lightweight rubber roll in which a thin wire having a constant diameter is spirally wound around an axis. The rotation of the liquid measuring device may be performed by forcibly rotating the rotation shaft in a forward or reverse direction at a certain peripheral speed, or may be performed at least only when the plate is passed. The pressing weight can sufficiently cover the range with the weight of the liquid measuring tool alone, but if the entire liquid measuring tool is pressed with a pressure roll or the like, or if the nip pressure is applied to both ends, substantial pressing The weight may be increased.

The printing plate in which the non-image portion has been dissolved enters a non-image portion removal and disposal step, in which the removing means removes the dissolved image forming layer component remaining in the non-image portion, and is further conveyed to the next step. Most of the removal liquid removed in the non-image portion removal and disposal step is disposed of because it is a dissolved image forming layer component and a fatigue alkaline treatment liquid. In addition, it is necessary to replenish the circulating liquid with at least the amount of the alkaline processing liquid contained in the waste liquid to ensure the amount of the circulating liquid and maintain the alkaline processing activity.

As the removing means in the non-image portion removing step according to the present invention, a method using an air knife, a rubber blade, an elastic roll, a rotating and non-rotating (fixed or sliding) brush, a Molton roll, or the like is used. And the like. The elastic roll can remove the alkaline processing liquid on the plate surface by the nip pressure between the pair of rolls through the printing plate, and the rubber blade is a state where at least the contact surface with the plate has a smooth elastic material along the transport path of the printing plate. It is possible to remove the alkaline processing liquid from the plate surface by arranging the plate and sliding the plate surface. Examples of the elastic material used for these include silicone rubber, neoprene rubber, butyl rubber, ethylene propylene rubber, nitrile butadiene rubber, and Teflon coated rubber.

When installing the rubber blade, a guide roll that rotates at a peripheral speed higher than the transport speed is provided below the rubber blade, or pressure is applied immediately after the leading edge of the plate has passed through the rubber blade to prevent the occurrence of defective transport. It is desirable to provide some mechanism for this. In the removal using a Molton roll and a brush, a small amount of processing liquid may be supplied at least at the time of removal in order to promote the removal and removal of the dissolved image forming layer components. In the present invention, a rubber blade is preferably used for comprehensive reasons such as reduction of the maintenance and management burden on the mechanism, reduction of the amount of waste liquid, removal efficiency, and prevention of deterioration of the alkaline treatment quality. In order to improve the pressurization, a pressurizing auxiliary member such as a metal plate and a means may be used on the side opposite to the plate contact surface of the rubber blade.

The printing plate carried out from the non-image portion removing and discarding step is supplied with a rinsing solution in the rinsing step to completely remove a small amount of remaining removed matter from the plate. A rinsing liquid supply method in the rinsing processing step can use a conventionally known liquid supply mechanism such as a shower similarly to that of the alkaline processing liquid, but unlike the processing in the alkaline processing liquid, the rinsing processing is performed quickly with the rinsing liquid. It must be possible to completely remove the liquid material remaining on the plate. Therefore, if the liquid supply is a mechanism capable of suppressing the scattering of the liquid, Japanese Patent Laid-Open No. 3-1095
It may be supplied directly to the plate by the method described in JP-A-75-75, or may be supplied together with compressed air by the method described in JP-A-4-261543. The processing method used in the rinsing process may be a disposable method or a cyclic reuse method, or another method can be used if desired.

After the rinsing treatment, the printing plate is usually coated with a protective gum solution, processed, and dried with hot air or the like, if necessary, before printing. The method of supplying the protective gum solution in the protective gum solution treatment step may be any method as long as the entire surface of the plate can be covered with the protective gum solution, and a conventionally known solution supply mechanism, for example, a shower, a spray, a dip method or the like can be used.

Next, the non-image area alkali dissolving and removing type planographic printing plate to be processed in the present invention will be described. The non-image portion alkali dissolution-removable lithographic printing plate is a photosensitive lithographic printing plate having a photosensitive layer as an image forming layer on a support or an electrophotographic lithographic printing plate having a photoconductive layer in the same manner. As the support used for these printing plates, aluminum, zinc, copper-aluminum, copper-stainless, chromium-copper,
A support having a metal plate such as chromium-copper-aluminum or chromium-copper-stainless steel as a base and at least a surface on which an image forming layer is provided, subjected to a hydrophilization treatment may be mentioned. Further, their thickness is preferably 0.07 to 2.0 mm, more preferably 0.1 to 0.5 mm. Among these substrates, an aluminum plate is preferably used. This aluminum plate is
Aluminum may be contained as a main component and a trace amount of a different element may be contained, and conventionally known and publicly available materials can be appropriately used.

In order to impart desired surface properties to the surface of the support on which the image forming layer is to be provided, it is preferable to perform graining and anodic oxidation by a known method. Prior to the graining treatment, a degreasing treatment with a surfactant or an aqueous alkali solution may be performed.
Graining methods include mechanical surface roughening, electrochemical surface roughening, and chemical surface selective dissolution. The roughened substrate is used after being subjected to an alkali etching treatment and a neutralization treatment as necessary. The treated substrate is anodized to form an oxide film on its surface. Anodized film weight may have 0.1 to 10 g / m ^2, and more is preferably 1 to 6 g / m ^2.

On the support thus obtained, an intermediate layer of an amino acid type, an amide type, an organic phosphoric acid type or the like is provided, if necessary, for the purpose of improving the adhesion of the image forming layer and the resistance to printing stains. After that, an image forming layer is provided to obtain a photosensitive lithographic printing plate (PS plate) or an electrophotographic lithographic printing plate.

The PS plate which can be treated by the treatment method of the present invention includes a diazo resin (a salt of a condensate of p-diazophenylamine and paraformaldehyde) as described in British Patent No. 1,350,521. ) And shellac, and a diazo resin described in British Patent Nos. 1,460,978 and 1,505,739 and a hydroxyethyl methacrylate unit or a hydroxyethyl acrylate unit. Negative PS having photosensitive layer comprising mixture with polymer having repeating units
And a positive PS plate having a photosensitive layer comprising a mixture of an o-quinonediazide photosensitive substance and a novolak-type phenol resin as described in JP-A-50-125806.

Further, PS plates having a photosensitive layer composed of a photocrosslinkable photopolymer as described in US Pat. No. 3,860,426, and US Pat. Nos. 4,072,527 and 4, PS plate having a photosensitive layer made of a photopolymerizable photopolymer as described in JP-A-0772528, etc., and described in British Patent Nos. 1,235,281 and 1,495,861. PS plates having a photosensitive layer comprising a mixture of an azide and a water-soluble polymer as described above are also known and can be used for these.

As an electrophotographic planographic printing plate, a printing plate having a photoconductive layer comprising an organic light guide and a polymer material containing an alkali-soluble group (acid or acid anhydride group) described in JP-B-37-17162 is used. JP-B-38-6961 discloses a printing plate having a photoconductive layer containing a low-molecular-weight alkali-soluble organic photoconductor, and a printing plate comprising vinyl acetate and an alkali-soluble group-containing vinyl compound described in JP-B-41-2426. Printing plate having photoconductive layer containing copolymer, printing plate having photoconductive layer containing photopolymerizable photoconductive compound described in JP-B-41-39405, JP-B-47-3
No. 6778, a printing plate having a photoconductive layer containing a quinacridone pigment and an organic resin binder such as a phenol resin, and a light plate containing a phthalocyanine pigment and a hydrophilic resin described in JP-A-54-89801. A printing plate having a conductive layer, a printing plate having a photoconductive layer containing a specific ratio copolymer of a vinyl group-containing carboxylic acid and an ester of methacrylic acid and / or acrylic acid described in JP-B-2-43181, Styrene described in JP-A-2-44065 /
A printing plate having a photoconductive layer containing a maleic acid monoester copolymer is exemplified.

[0036] These photosensitive lithographic printing plate and an electrophotographic lithographic printing plate can be imaged by the operation of the publicly known. That is, the former develops the non-image area after exposure with alkali, and the latter elutes the non-image area after charging, exposure and toner development. As an exposure method, a xenon lamp, a tungsten lamp, a fluorescent lamp or the like as a light source, a reflection image exposure, a contact exposure through a transparent positive film, and a lithographic printing plate having a high-sensitivity type photosensitive layer or photoconductive layer. , Laser light, scanning exposure using a light emitting diode, or the like. When performing scanning exposure, a He-Ne laser, a He-Cd laser,
Argon ion laser, krypton ion laser, ruby laser, YAG laser, nitrogen laser, dye laser, excimer laser, GaAs / GaAlAs, InGa
Scanning exposure using a laser light source such as a semiconductor laser such as AsP, alexandrite laser, copper vapor laser, or scanning exposure using a light emitting diode and a liquid crystal shutter (a line printer type light source using a light emitting diode array, a liquid crystal shutter array, etc.) ).

In the case of an electrophotographic planographic printing plate, toner development is performed next. As the toner developing method, a dry developing method (cascade developing, magnetic brush developing, powder cloud developing) and a liquid developing method are known, and any of them can be used. In particular, the liquid developing method can form a fine toner image and is suitable for producing a printing plate having good reproducibility. Further, positive / positive development by positive development and negative / positive development by reversal development under application of an appropriate bias voltage are also possible. The formed toner image can be fixed by a known fixing method such as heat fixing, pressure fixing, and solvent fixing. As the toner component, a known composition having a resist property in the following alkaline processing liquid can be used.

The printing plate on which an image has been formed is treated with an alkaline processing solution to remove non-image portions. The alkaline treatment liquid that can be used in the present invention is preferably an aqueous liquid containing an alkaline agent and having a buffering capacity. Conventionally, as an alkaline agent used for a photosensitive lithographic printing plate developer and an electrophotographic lithographic printing plate eluate, a general formula SiO ₂ / M ₂ O (M = Li, N
a, silicates represented by K), alkali metal hydroxides,
Examples thereof include inorganic alkali agents such as alkali metal and ammonium salts of phosphoric acid and carbonic acid, organic alkali agents such as ethanolamines, triethylamine, dibutylamine, ethylenediamine, triethylenetetramine, and morpholine, and mixtures thereof.

Further, in order to promote the penetration of the alkaline agent into the non-image area and to shorten the alkaline processing time, particularly in an electrophotographic lithographic printing plate, ethanol is used within a range in which toner peeling is not induced during the alkaline processing. , 2-propanol, 2-
In addition to water-soluble organic solvents such as alkoxyethanol, N-methylpyrrolidone and aromatic alcohols such as benzyl alcohol, sulfites and the like may be used in combination.

The alkaline processing liquid is further described in
No. 25100, ionic compounds described in JP-A-55-
A water-soluble cationic polymer described in JP-A-95946, a water-soluble amphoteric polymer electrolyte described in JP-A-56-142528, a neutral salt described in JP-A-58-75152,
Chelating agents described in JP-A-58-90952, liquid viscosity modifiers described in JP-A-1-177541, preservatives and bactericides described in JP-A-63-226657, and various surfactants, natural Known components such as a synthetic water-soluble polymer and the like can be contained as necessary.

In the printing plate from which the non-image area image forming layer has been dissolved and removed, the rinsing solution is used to remove the dissolved components remaining on the plate surface and the alkaline processing solution, and if necessary, the plate surface is improved in scratch resistance and the non-image area is insensitive. It is subjected to a protective gum treatment for the purpose of fatification and the like, and then provided for printing. As the rinsing liquid and the protective gum liquid that can be used in the present invention, known liquids can be used.

[0042]

EXAMPLES The present invention will be described more specifically with reference to examples, but the present invention is not limited to the following examples unless it exceeds the gist of the invention.

Example 1 The surface of a JIS 1050 aluminum sheet was grained with a rotating nylon brush using a pumice / water suspension as an abrasive. After washing with water, the substrate was immersed in a 10% by weight aqueous solution of sodium hydroxide at 60 ° C., and etched so that the amount of aluminum dissolved was 6 g / m ² . After washing with water, add 1%
The sample was immersed for 5 minutes to neutralize, and sufficiently washed with water. Subsequently, electrolytic surface roughening is performed in a 3% by weight aqueous hydrochloric acid solution, and the 20% by weight at 50 ° C.
After immersing in a sulfuric acid aqueous solution to wash the surface, the surface was washed with water.
Further, anodizing treatment was performed in a 20% by weight aqueous sulfuric acid solution to form an aluminum oxide film on the surface, and the substrate was washed with water and dried to obtain a support. The coating liquid for forming a photoconductive layer described in Table 1 dispersed in a dyno mill for 1 hour was applied to the surface-treated surface of the support so that the coating amount of the solid content was 4.4 g / m ^2, and then the mixture was heated at 90 ° C. After drying for 30 seconds, an electrophotographic planographic printing plate (printing plate A) was obtained.

[0044]

[Table 1]

This printing plate was cut into an A2 size, heated at 50 ° C. for 2 hours while shielding from light, and then allowed to stand at room temperature. next,
After being charged in a dark place so that the surface potential of the photoconductive layer becomes approximately +280 V, scanning image exposure is performed using a semiconductor laser (780 nm), and immediately a positively charged toner (manufactured by Mitsubishi Paper Mills, Ltd.
Reverse development (bias voltage: +1) using OM-ED III)
20 V), dried with cold air to remove the toner dispersion medium, and further heat-fixed to form a toner image on the photoconductive layer. The obtained toner-developed printing plate was subjected to plate making using a lithographic printing plate processing apparatus as shown below.

FIG. 1 shows a planographic printing plate processing apparatus used in this embodiment. The basic configuration of this processing apparatus is composed of four zones: an alkaline processing solution application zone A, a non-image area removal / discard zone B, a rinsing process zone C, and a protective gum application zone D. The printing plate is transported in the direction of the arrow. By being inserted into the line 1, it is nipped by a pair of rolls, is automatically transported, and is subjected to a plate making process.

The alkaline processing liquid application zone A is further provided with an alkaline processing liquid supply section comprising a processing liquid supply pipe 27, a rectifying plate 28, and a liquid supply roll 11a, and a liquid measurement section comprising a liquid measuring tool 47 and a guide roll 13. It consists of. As the liquid measuring tool 47, a wire bar is used, and forcible drive transmission is not performed to the wire bar, and rotation is transmitted by contact with a translation plate during liquid measurement. The alkaline processing liquid 16 is rectified by the rectifying plate 28 from the processing liquid supply pipe 27 and supplied to the plate via the liquid supply roll 11a, and the alkaline processing liquid measured by the liquid measuring unit is supplied to the upper part of the alkaline processing liquid storage tank 3. The liquid flows on the liquid guide plate 75 installed in the processing liquid storage tank 3 again through the liquid drop hole 78.

The processing liquid storage tank 3 is replenished with a reduced amount of the alkaline processing liquid 16 with a replenisher. Immediately after the 50th printing plate has passed the liquid measuring tool 47, the replenisher 19 is supplied from the replenisher tank 7 to the replenisher pump 94 and the pipe 1
The liquid metering tool 47 is supplied to the liquid measuring tool 47 via the replenishing liquid supply pipe 54 and the liquid metering tool 47, and is replenished to the level sensor upper limit (not shown) while cleaning the liquid measuring tool 47.

The non-image portion removal waste zone B includes a scraping blade 22 and a backup roll 2 which are means for removing the non-image portion image forming layer dissolved by the alkaline processing liquid.
0, and a non-image portion removing section comprising a backup roll cleaning blade 23, a cleaning and removing liquid supply means including a cleaning and removing liquid supply pipe 52 for supplying a circulating rinsing liquid to the scraping blade 22, and a removing waste liquid primary storage tank 4. Is done. The pressure of the scraping blade 22 was adjusted so that the width of contact with the backup roll 20 was minimized in a range where removal of the dissolved non-image portion image forming layer was optimally performed. Scraping blade 22
The liquid scraped off by this is temporarily stored in the removal waste liquid primary storage tank 4 and then discarded into the removal waste liquid secondary storage tank 9 via the pipe 114.

The rinsing treatment zone C is provided with a circulating rinsing liquid supply unit for supplying the circulating rinsing liquid 36 stored in the circulating rinsing liquid storage tank 5 directly from the two circulating rinsing liquid supply pipes 37 and 38 to the plate surface, and transporting. It is arranged in parallel with the roll pairs 31 and 32, and comprises an unused rinsing liquid supply unit for discharging an unused rinsing liquid from the spray gun 33 together with compressed air from a compressed air source (not shown).

An unused rinsing liquid storage tank (not shown) is arranged above the spray gun 33 so that the unused rinsing liquid is supplied to the spray gun 33. The supply of the unused rinsing liquid is performed in such a manner that the unused processing liquid supply control means (not shown) discharges the printing plate from the leading end portion to the transport roll pair 31 until the rear end portion of the printing plate passes the transport roll pair 32. Is set to

The protective gum liquid application zone D includes a protective gum liquid supply pipe 45, a surface roughening liquid measuring roll 43, and a liquid supply roll 4.
0, a protective gum solution supply unit comprising a lower guide roll 41, a cleaning means including a cleaning solution supply pipe 60 for cleaning the protective gum solution supply unit, a protective gum solution storage tank 8 for storing the protective gum solution 46, and an excess It comprises a protection gum solution primary storage tank 6 for receiving the protection gum solution. The protective gum solution supplied from the protective gum solution supply pipe 45 is measured by the surface roughening solution measuring roll 43 and supplied onto the printing plate, and is extended and squeezed by the roll pairs 40 and 41.

In the plate making process, in addition to the treatment solutions having the compositions shown in Tables 2 to 4, GU-7 (manufactured by Fuji Photo Film Co., Ltd.) was used as a protective gum solution diluted to the use form. . The unused rinse liquid was filled with an unused liquid having the same composition as the rinse liquid.

[0054]

[Table 2]

[0055]

[Table 3]

[0056]

[Table 4]

The cleaning of the scraping blade 22 is performed for 2 seconds after the trailing edge of the last printing plate passes through the scraping blade 22 by the operation of the liquid feed pump 95 for substantially 15 seconds. The cleaning material was supplied to the surface of the scraping blade where the removed material was attached, and was cleaned. Under the above processing conditions, 50 at 50 seconds
After the continuous plate making, the scraping blade was washed, and a total of 4000 plates were made under the conditions of continuous plate making. Incidentally, the replenisher and the unused rinse were appropriately replenished to their respective storage tanks in accordance with the amount of loss in use.

As a result, the alkaline processing liquid A stored in the processing liquid storage tank 3 was dyed blue due to inflow mixing of the alkali-dissolved photoconductive layer composition during the plate-making period, and the viscosity was slightly increased. No plate making process failure was observed in the plate making of the plate, and there was almost no change in the side etch as compared with the plate making of the 100th and 1000th plate. The pH of the alkaline treatment liquid after the 4,000-plate making and the pH of the waste liquid in the secondary waste storage tank 9 were measured and found to be 12.77 and 11.57, respectively.

When 0.6% by weight of ammonium bicarbonate (pH reducing agent 1) was added to the treating solution storage tank 3 containing the alkaline treating solution A while stirring, the temperature of the treating solution almost increased. No solution pH was 12.32. Further, when the waste liquid whose pH was lowered was injected into a waste liquid tank through a 100-mesh net, the liquid could be injected smoothly without particularly accumulating insoluble matter on the mesh.

Comparative Example 1 The same amount of concentrated nitric acid (pH-lowering agent 2) was added to the alkaline processing solution A, which had been subjected to the same plate-making process as in Example 1, in place of the pH-lowering agent 1 used in Example 1. did. After the concentrated nitric acid injection, the alkaline processing liquid A immediately generates heat and agglomerates at the bottom of the processing liquid storage tank 3.
When an attempt was made to transfer the liquid to the waste liquid tank through a mesh net, aggregates accumulated on the mesh, and the liquid could not be transferred smoothly. In addition, the pH of the solution finally dropped only to 12.63, and a pH-lowering agent had to be added.

Example 2 The alkaline processing solution A made in the same manner as in Example 1 was separated into another container, and the same amount of diammonium carbonate (pH lowering agent) was used instead of the pH reducing agent 1 used in Example 1. Agent 3) and sodium hydrogen carbonate (pH lowering agent 4) were added to the vessel containing the alkaline treatment liquid A while stirring. As a result, similarly to Example 1, the temperature of the treatment liquid hardly increased, and the pH of both treatment liquids was around 12.4. Further, when these liquids were injected into a waste liquid tank through a 100-mesh net, any of the liquids could be injected smoothly without particularly accumulating aggregates on the mesh.

Example 3 The surface of a JIS1050 aluminum sheet was grained with a rotary nylon brush using a pumice / water suspension as an abrasive. After washing with water, the substrate was immersed in a 10% by weight aqueous solution of sodium hydroxide at 60 ° C., and etched so that the amount of aluminum dissolved was 6 g / m ² . After washing with water, add 1%
The sample was immersed for 5 minutes to neutralize, and sufficiently washed with water. Subsequently, electrolytic surface roughening is performed in a 2% by weight aqueous solution of nitric acid, and 50% by weight of 20% by weight.
After immersing in a sulfuric acid aqueous solution to wash the surface, the surface was washed with water.
Further, anodizing treatment was performed in a 20% by weight aqueous sulfuric acid solution to form an aluminum oxide film on the surface, and the substrate was washed with water and dried to obtain a support. Table 5 shows the surface treated surface of the support.
The coating solution for forming a photosensitive layer described above has a solid content of 2.1 g / m ^2.
After coating, the resultant was dried at 90 ° C. to obtain a photosensitive lithographic printing plate (printing plate B).

[0063]

[Table 5]

This printing plate B was cut into A2 size, and exposed through a positive original from a distance of 80 cm using a 2 KW metal halide lamp. Subsequently, the lithographic printing plate processing apparatus used in Example 1 and Table 6 to Table 6 Plate-making was performed using the processing solutions shown in Table 9. In addition, from the suitability of the plate making process, in the lithographic printing plate processing apparatus used in Example 1, the liquid measuring tool 47 disposed on the guide roll 13 was moved onto the transport roll 17,
Immediately before the alkali treatment time, the plate making speed was adjusted such that the non-image part photosensitive layer was completely dissolved just before the non-image part removal and disposal step was carried in.

[0065]

[Table 6]

[0066]

[Table 7]

[0067]

[Table 8]

[0068]

[Table 9]

A total of 4,000 plates were made under the same processing conditions as in Example 1 except that the plate conveying speed was changed. The pH of the alkaline treatment liquid B after plate making and the pH of the waste liquid in the secondary liquid storage tank 9 were measured and found to be 13.17 and 12.65, respectively.

When 1.5% by weight of ammonium bicarbonate (pH reducing agent 1) was added to the treatment liquid storage tank 3 containing the alkaline treatment liquid B while stirring, the ammonium bicarbonate was slowly dissolved. And the pH of the solution is 12.
It was 29. Further, when this treatment liquid was poured into a waste liquid tank through a 100-mesh net, the liquid could be smoothly poured without particularly accumulating insoluble matter on the mesh.

Similarly, potassium bicarbonate (p
H-depressant 5) 0.2 wt% was added with stirring, and the pH of the solution became 12.33. During this time, almost no increase in the liquid temperature was observed, and no aggregation occurred.

Comparative Example 2 The same amount of disodium carbonate (pH lowering agent 6) or magnesium carbonate (pH lowering agent 7) as in Example 3 was added to an alkaline treatment solution that had undergone exactly the same plate making process as in Example 3. Was added. As a result, although the pH lowering agent 5 had no problem in solubility, heat generation, and aggregation, it was ineffective due to the strong buffering capacity of disodium carbonate itself or a slight decrease in the pH of the alkaline treatment solution. Further, the pH lowering agent 6 did not dissolve in the alkaline processing liquid, but only settled at the bottom of the processing liquid storage tank 3, and did not lower the pH of the processing liquid, which was also ineffective.

[0073]

As described above, when the alkaline processing solution fatigued by the plate-making process is processed by the method for processing a lithographic printing plate of the present invention, it is easy to handle a wide range of pH of the highly alkaline processing solution. And an excellent effect that the processing load of the processing waste liquid is reduced.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view of a planographic printing plate processing apparatus used for performing a plate making process according to a processing solution processing method for a planographic printing plate of the present invention.

[Explanation of symbols]

 A Alkaline treatment liquid application zone B Non-image area removal and disposal zone C Rinse treatment zone D Protective gum solution application zone 1 Printing plate transport line 3 Alkaline treatment liquid storage tank 9 Removal waste liquid secondary storage tank 16 Alkaline treatment liquid

Claims (1)

(57) [Claims] 1. A lithographic printing plate making method in which an alkaline processing liquid is supplied to an image-formed lithographic printing plate to dissolve the non-image portion, and then the alkaline processing solution and the dissolved non-image portion on the printing plate are removed. A method for treating a treatment liquid in the treatment, wherein at least one selected from an alkali metal hydrogencarbonate and an ammonium salt, and diammonium carbonate is added to a liquid containing at least an alkaline treatment liquid fatigued by the treatment. And then discarding the treatment liquid. A method for treating a lithographic printing plate.