JPS6339895B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a positive photosensitive lithographic printing plate (Pre-
It is also called Sensitized Plate (pre-sensitized plate) and abbreviated as PS version. ) development method, especially when a positive PS plate having a photosensitive layer containing an o-quinonediazide compound as a photosensitive material is processed in large quantities using an automatic processor, so that the development process can always give a constant result. The invention relates to a developing method.

Conventionally, the most widely used positive-working PS plate is one in which a photosensitive layer made of an o-quinonediazide compound is provided on an aluminum plate as a support. An o-quinonediazide compound is, for example, a compound containing a structural unit represented by the following general formula (), and decomposes when irradiated with actinic rays to form a compound having a carboxyl group as shown by the general formula (). This is already known [O. Su¨s, Liebigs Annalen der Chemie, vol. 556]
See page 65 (1944)].

Therefore, a positive PS in which a photosensitive layer made of an o-quinonediazide compound is provided on an aluminum support.
When the plate is exposed to actinic radiation through a transparency, the o-quinonediazide compound present in the exposed areas of the photosensitive layer is converted to carboxylic acid, and therefore, when this is developed with an alkaline aqueous solution, only the exposed areas of the photosensitive layer are exposed. It is removed to expose the support surface.
Since the surface of the aluminum support is hydrophilic, the portions of the support surface exposed during development (non-image areas) retain water and repel oil-based ink for lithographic printing. On the other hand, the areas (image areas) of the photosensitive layer that are not removed by development are lipophilic and repel water.
Accepts the above inks. The alkaline aqueous solution used as a developer for such positive PS plates is
Various solutions are known, but the most preferred is an aqueous solution of sodium silicate. The reason for this is that the etching effect on the aluminum support is poor, as well as the ratio of silicon oxide (SiO ₂ ) and sodium oxide (Na ₂ O), which are components of sodium silicate (generally expressed as the molar ratio of SiO ₂ /Na ₂ O). This is because the developability can be adjusted to some extent by adjusting the density.

In recent years, automatic developing machines for PS plates have been widely used in the printing industry to streamline and standardize plate-making operations, and processing equipment that sprays processing liquid as shown in Figure 1 is generally used. . In this processing device, a plurality of nozzle pipes 3 are provided above the conveyance path, and the developing solution in the tank 4 is is injected onto the surface of the photosensitive layer of the PS plate from the nozzle of the nozzle pipe 3 by the pump 7, and if necessary, the surface of the photosensitive layer is further rubbed with a brush roller (not shown) or the like for development. The used developing solution is collected into a tank 4 after passing through a filter 6 to remove insoluble matter.
Then, the sensing means 8 senses that the PS plate has been inserted into the processing device, and the jetting of the developer from the nozzle is thereby started, and when the PS plate has finished passing through the processing device, the jetting of the developer is stopped. It is customary for it to stop.

When developing a positive-working PS plate using such an automatic processor, an alkali metal silicate containing at least 20% potassium, based on the total gram atoms of all alkali metals present in the developer, is used as the developer. Using an aqueous solution, changes in the developer that change with the progress of development and/or over time (mainly a decrease in alkali activity) are obtained by using an aqueous solution that has an alkali activity higher than that of the developer described above, and in the tank by compensating by adding to the developer solution a replenisher consisting of an aqueous solution of an alkali metal silicate of at least 20% potassium based on the total alkali metal gram atoms present therein. without changing the developer.
The fact that it is possible to develop a large amount of positive PS plates,
It is disclosed in Japanese Patent Application No. 53-96307 (Japanese Unexamined Patent Publication No. 55-25028).

However, the specific method of adding the above-mentioned replenisher to the developer is to process a printing plate of a certain fixed area and prevent the resulting decrease in the apparent sensitivity of the PS plate in the subsequent processing. Determine the required amount of replenisher as described above through practical skill, convert it into the amount required per unit area of the printing plate to be processed, and then calculate the amount equivalent to the area of the printing plate to be processed for each PS plate processing. It has been found that the method of adding an average required amount of replenisher at regular intervals or at regular intervals to compensate for the decrease in the alkaline component in the developer results in the following drawbacks. In other words, when a large number of plates are processed in a short period of time with this method, adding a pre-calculated amount of replenisher will actually increase the proportion of alkaline components and reduce the apparent sensitivity of the PS plate. If the increase is significant, it may result in poor printing durability or poor inking as a printing plate.On the other hand, if only a small amount of printing plates are processed over a long period of time, This resulted in a disadvantage that the apparent sensitivity of the PS plate was reduced, and in severe cases, the resulting lithographic printing plate produced printed matter with many stains. The reason for this shortcoming is that the average replenishment amount described above compensates for the activity of the developer that decreases due to the processing of positive-tone PS plates and absorbs carbon dioxide gas from the air over time. It has been found that this is because the amount to compensate for the activity of the developer which decreases due to the deterioration of the developer is determined together.

The present invention has been made with the aim of eliminating the above-mentioned drawbacks, and its gist is o
- A method in which a positive-working photosensitive lithographic printing plate having a photosensitive layer made of a quinonediazide compound is imagewise exposed and then developed with a developer made of an aqueous solution of an alkali metal silicate, the method comprising: A first replenisher consisting of an aqueous solution of an alkali metal silicate having an alkali activity higher than that of the developer is applied to one sheet of the positive photosensitive lithographic printing plate. (2) a second replenishment consisting of an aqueous solution of an alkali metal silicate having an alkaline activity higher than that of the developer; In a method for developing a positive-working photosensitive lithographic printing plate, the method comprises adding a developer to the developer (a) continuously in a fixed proportion, or (b) in a fixed quantity intermittently at fixed time intervals. , the developer solution, the first replenisher solution and the second replenisher solution each contain at least 20% gram atoms of potassium based on the total gram atoms of alkali metal present therein; This is a characteristic developing method.

The positive PS plate targeted by the developing method of the present invention is
Basically on an aluminum plate as a support,
It has a photosensitive layer made of an o-quinonediazide compound. Suitable aluminum plates include pure aluminum plates and aluminum alloy plates, as well as plastic films laminated or vapor-deposited with aluminum. The surface of the aluminum plate is preferably subjected to a surface treatment such as graining treatment, immersion treatment in an aqueous solution of sodium silicate, potassium fluorozirconate, phosphate, or the like, or anodization treatment. In addition, as described in U.S. Patent No. 2,714,066, an aluminum plate that has been grained and then immersed in an aqueous sodium silicate solution, and as described in Japanese Patent Publication No. 47-5125, an aluminum plate can be used as an anode. Those obtained by oxidation treatment and then immersion treatment in an aqueous solution of an alkali metal silicate are also suitably used. The above anodic oxidation treatment can be performed using, for example, phosphoric acid, chromic acid, sulfuric acid,
This is carried out by passing an electric current through an aluminum plate in an electrolytic solution consisting of an aqueous solution or a non-aqueous solution of an inorganic acid such as boric acid, an organic acid such as oxalic acid or sulfamic acid, or a salt thereof, or a combination of two or more thereof.

Also effective is silicate electrodeposition as described in US Pat. No. 3,658,662.

Furthermore, US Patent No. 4087341, Japanese Patent Publication No. 46
Also useful are supports coated with electrolytic grains as disclosed in Japanese Patent Laid-Open No. 52-30503 and No. 52-30503, which are anodized as described above.
Also preferred are aluminum plates that are grained, chemically etched, and then anodized, as described in U.S. Pat. No. 3,834,998. These hydrophilic treatments are performed not only to make the surface of the support hydrophilic, but also to prevent harmful reactions with the photosensitive composition provided thereon, and to improve the adhesion with the photosensitive layer. It is applied for various purposes, such as to improve the quality of life.

The photosensitive layer provided on the hydrophilic surface of the support consists of an o-quinonediazide compound. Particularly preferred o-quinonediazide compounds are o-naphthoquinonediazide compounds, such as those described in U.S. Pat.
No. 3046110, No. 3046111, No. 3046121, No. 3046115, No. 3046118, No. 3046119,
Same No. 3046120, Same No. 3046121, Same No. 3046122,
Same No. 3046123, Same No. 3061430, Same No. 3102809,
It is described in numerous publications including the specifications of the same No. 3106465, the same No. 3635709, and the same No. 3647443, and these can be suitably used. Among these, aromatic hydroxy compounds o-
Naphthoquinone diazide sulfonic acid ester or o-naphthoquinone diazide carboxylic acid ester is preferable, and in particular, a condensate of pyrogallol and acetone described in US Pat. No. 3,635,709 is ester-reacted with o-naphthoquinone diazide sulfonic acid; O-naphthoquinonediazide sulfonic acid, polyester having a hydroxyl group at the end described in U.S. Patent No. 4,028,111;
or an ester reaction product of o-naphthoquinonediazidecarboxylic acid, a homopolymer of p-hydroxystyrene as described in U.S. Pat. No. 4,139,384, or a copolymer of this with other copolymerizable monomers. Those obtained by subjecting o-naphthoquinonediazide sulfonic acid or o-naphthoquinonediazidecarboxylic acid to an ester reaction are very excellent.

Although these o-quinonediazide compounds can be used alone, it is preferable to mix them with an alkali-soluble resin and provide this mixture as a photosensitive layer. Suitable alkali-soluble resins include novolak type phenolic resins, and specifically include phenol formaldehyde resins, o-cresol formaldehyde resins, m-cresol formaldehyde resins, and the like. Additionally, U.S. Patent No.
As described in the specification of No. 4123279, in addition to the above-mentioned phenol resin, a condensate of phenol or cresol substituted with an alkyl group having 3 to 8 carbon atoms such as t-butylphenol formaldehyde resin and formaldehyde can be used. It is even more preferable to use them together. Alkali soluble resin is
About 50 to about 85% by weight in the photosensitive layer, more preferably 60 to about 85% by weight
Contains 80% by weight.

Additives such as dyes, plasticizers, and components imparting printout performance can be added to the photosensitive layer made of the o-quinonediazide compound, if necessary.

A photosensitive composition comprising such o-naphthoquinone diazide is coated onto a support from a solution in a suitable solvent. Suitable solvents include glycol ethers such as ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, and 2-methoxyethyl acetate, ketones such as acetone, methyl ethyl ketone, and cyclohexanone, and chlorinated hydrocarbons such as elendichloride. .

The coating amount of the photosensitive layer made of an o-quinonediazide compound provided on the support is approximately
0.5 to about 7 g/ ^m2 , more preferably 1.5 to 3
g/ ^m2 .

There are many types of such positive PS plates commercially available, and these can be used for carrying out the present invention. Examples of commercially available positive PS plates include “GAP-”, “SGP-”, and “SGP-K”.
(Both manufactured by Fuji Photo Film Co., Ltd.); “P-7”,
"P-7s", "P-3", "P-3s" (all made by Hoechst, West Germany); "Alinpick Gold", "Spartan" (all made by Hawthorne Allographie, UK), etc. be.

When these positive PS plates are exposed through a transparent original to active ray-rich light such as a carbon arc lamp, mercury lamp, metal halide lamp, or tungsten lamp, the exposed portion of the photosensitive layer becomes alkali-soluble. Therefore, with an alkaline aqueous solution,
The exposed portions of the photosensitive layer are eluted and the hydrophilic surface of the support is exposed.

By the way, when developing a positive PS plate, the desired and appropriate development result can be obtained immediately after preparing the developer, but the amount of development of the positive PS plate, the time elapsed after preparing the developer, and other factors As a result, the development activity of the developer decreases, so a replenisher is added to the developer to prevent the decrease in development activity.In the present invention, the developer (mother solution)
It is also characterized in that the composition of the replenisher is specific, and the replenisher is added to the developer by a specific method.

That is, the developer, the first replenisher, and the second replenisher used in the present invention all consist of an aqueous solution of an alkali metal silicate, and the aqueous solution has a characterized by containing at least 20% potassium atoms, and the alkaline activity of the first replenisher and the second replenisher is selected to be higher than the alkaline activity of the developer used in combination therewith. be done.
(1) The activity of the developer, which decreases due to developing the positive PS plate, is compensated for by adding the first replenisher, and (2) the second replenisher is added to the developer. (a) is added continuously in a fixed proportion, or (b) is added in a fixed quantity intermittently at fixed intervals.

The most characteristic developer used in the present invention, the first
Both the replenisher solution and the second replenisher solution are aqueous solutions of alkali metal silicate, and have at least
20% is made up of potassium. By using the silicate aqueous solution containing this specific amount of potassium, no insoluble matter is generated in the developer even when the positive PS plate described above is processed in large quantities. Therefore, the spray nozzle of the automatic developing machine is not clogged, and the filter, which is built into the automatic developing machine and through which the used developer is collected, is not clogged. This effect is extremely surprising since it can be obtained even when a positive-working PS plate using an anodized aluminum plate as a support, in which insoluble matter is considerably generated, is developed in large quantities. The preferred content of potassium is 20% to 90%, most preferably 30% to 80%.

Preferred sources of potassium mentioned above include:
Includes potassium hydroxide, potassium borate, potassium pyrophosphate, potassium triphosphate, potassium polyphosphate and potassium silicate. These potassium sources can be used alone or in combination.
Further, when a relatively highly dissociated potassium salt such as potassium chloride, potassium iodide, potassium nitrate, potassium citrate, or potassium acetate is used as a supply source, almost no effect is observed.

As the alkali metal of alkali metal silicate,
In addition to potassium, it contains lithium and sodium. Preferred alkali metals are potassium and sodium.

In the present invention, particularly preferred developers have a potassium concentration of at least 20% as described above and are SiO ₂ /M ₂ O, where M represents an alkali metal.
Same below. ) has a molar ratio of 1.0 to 1.5 (i.e.
[SiO ₂ ]/[M] (where, [SiO ₂ ] refers to the content of SiO 2 in a unit volume expressed in gram molecules, and [M] refers to the content in a unit volume of SiO ₂ expressed in gram atoms. An aqueous solution of an alkali metal silicate in which the content of M in unit volume (the same applies hereinafter) is 0.5 to 0.75) and the concentration of SiO ₂ is 1 to 4% by weight, most preferably [SiO ₂ ]/ [M] is 0.5~
0.75 and an aqueous solution of an alkali metal silicate having a SiO ₂ concentration of 1 to 3% by weight.

Particularly preferred first and second replenisher solutions, as described above, have a potassium concentration of at least 20% and a molar ratio of SiO ₂ /M ₂ O of 0.5 to 1.5 (i.e., [SiO ₂ ]/[ M] is 0.25 to 0.75). The first replenisher and the second replenisher are components (mainly alkaline components) of the developer consumed when the positive PS plate is processed and alkaline components neutralized by carbon dioxide gas in the air. This is added to compensate for the Therefore, as the positive PS plate is processed and the composition of the developer changes over time, by adding the replenisher, the composition can be maintained within the predetermined range as mentioned above. Any aqueous solution of an alkali metal silicate having an alkali activity higher than the activity can be used as the first replenisher and the second replenisher. For example, _an aqueous solution of alkali metal silicate having the same [SiO ₂ ]/[M] ratio as the aqueous solution of alkali metal silicate used in the developer may be used as a replenisher. When used, an aqueous solution of alkali metal silicate containing a higher concentration of SiO ₂ than the concentration of SiO ₂ in the developer is added to the first replenisher and/or the second replenisher.
Can be used as a replenisher. In addition, SiO ₂ in the developer
When using a replenisher having the same SiO ₂ concentration as that of the developer, the ratio of [SiO ₂ ]/[M] is such that an aqueous solution of alkali metal silicate, which is smaller than that of the developer, is used first.
It can be used as a replenisher and/or a second replenisher. Furthermore, the first replenisher and the second replenisher may have the same or different compositions and concentrations.

As described above, a person skilled in the art can easily determine how to determine the respective compositions of the developer, the first replenisher, and the second replenisher. It is also possible to divide the first replenisher or the second replenisher into two or more liquids, and to mix these liquids when adding them to the developer. For example, there is a method in which the replenisher is made into a concentrated liquid and diluted with water at the time of replenishment.
However, regardless of the composition of the aqueous alkali metal silicate solution, the gram atomic weight of potassium relative to the total gram atomic number of alkali metals contained in the developer, first replenisher, and second replenisher is Of course, it must be at least 20%.

If the amount of potassium relative to the alkali metal in the developer, first replenisher, and second replenisher is less than the above 20%, insoluble matter will be generated in the developer as the positive PS plate is processed. This causes problems such as clogging the spray nozzle and clogging the filter through which used developer is collected. Therefore, always keep the developer at 20%.
It is extremely important to maintain the above potassium concentration. In addition, the developer is generally supplied to the user as a concentrated solution, and the user dilutes this with water to make the developer.
When a concentrated sodium silicate aqueous solution with [SiO ₂ ]/[Na] of 0.75 or less is diluted with water containing divalent or higher metal ions such as calcium, magnesium, or aluminum (for example, water with a German hardness of 36°), it becomes cloudy. However, the developer, first replenisher, and second replenisher used in the present invention have the drawback that the developer, the first replenisher, and the second replenisher used in the present invention cause precipitation. The concentrated solution does not become cloudy even when diluted with hard water as described above, and therefore, the developer or replenisher thus prepared can be used in an automatic processor without any problem. Furthermore, when a positive PS plate with an anodized aluminum plate as a support is processed using an aqueous sodium silicate solution as a developer, white silicic acid is the main component, especially on the surface of the conveyor roller at the bottom of the automatic processor. Although significant deposits were generated, only a small amount of such development was observed in the developing method of the present invention.

The developer, first replenisher, and second replenisher used in the present invention may further contain an organic solvent. Examples of such organic solvents include benzyl alcohol, 2-butoxyethanol, triethanolamine, diethanolamine, monoethanolamine, glycerin, ethylene glycol, polyethylene glycol, and polypropylene glycol. Such an organic solvent is contained in the developer used in the developing method of the present invention in such a range that it is maintained at 5% by weight or less based on the total weight.
It can be contained in the developer or the first and second replenishers.

The developer or the first and second replenishers used in the present invention can further contain a surfactant. This improves the throughput of the developer (the amount of photosensitive layer that can be dissolved and removed by a unit volume of the developer), and also widens the range of development conditions (temperature, processing time, etc.) that yield optimal results. can. Preferred such surfactants include anionic surfactants and amphoteric surfactants. Preferred specific examples of anionic surfactants include alkylbenzenesulfonic acid salts such as sodium dodecylbenzenesulfonate (the alkyl group has 8 to 18 carbon atoms, more preferably 12 to 16 carbon atoms), such as isopropylnaphthalenesulfonate. Alkylnaphthalene sulfonates such as sodium chloride (the number of carbon atoms in the alkyl group is 3)
~10), formalin condensates of naphthalene sulfonates, dialkyl sulfosuccinates (the alkyl group has 2 to 18 carbon atoms), dialkylamide sulfonates (the alkyl group has 11 to 17 carbon atoms), etc. included. Preferred specific examples of amphoteric surfactants include imidazoline derivatives such as N-alkyl-N,N,N-tris(carboxymethyl)ammonium (the alkyl group has 12 to 18 carbon atoms), N
-Alkyl-N-carboxymethyl-N,N-dihydroxyethylammonium (the number of alkyl groups is 12 to 18) and other betaine type compounds are included. The amount of surfactant used is not particularly limited, but is generally about 0.003% of the total weight of the developer.
~3% by weight, more preferably 0.006-1% by weight
It is included in the developer and replenisher so that it is maintained within the range of .

The developer and replenisher used in the present invention include:
Furthermore, an antifoaming agent can be included. Suitable antifoam agents include U.S. Pat. No. 3,250,727;
There are compounds described in various specifications such as British Patent No. 1382901 and British Patent No. 1387713. Among these, organic silane compounds are preferred.

Next, the method of adding a replenisher, which is the second feature of the present invention, will be explained mainly with reference to an embodiment using a processing liquid injection type automatic developing machine.

In the present invention, the first replenisher is added in such an amount as to restore the activity of the developer which decreases due to the development of the imagewise exposed positive PS plate. Therefore, when processing with an automatic processing machine such as the one mentioned above, it is necessary to
The amount (C) that compensates for the developer that is neutralized by dissolving and removing the exposed portion of the photosensitive layer of the PS plate, and the amount that is neutralized by the sprayed developer absorbing carbon dioxide gas in the air. is the sum of the amounts (A) that compensate for A
The amount depends on the automatic processor used, the developer and the first
Once each replenisher is specified, it will be determined automatically, so it will not be difficult to implement, but the amount of C is assumed to be large when processing a large amount of the same brand as a positive PS plate. It is an amount that varies depending on the exposed area in image exposure, even if
For example, the area of the non-image area of a lithographic printing plate obtained by developing an image-exposed positive PS plate is optically measured, and the analog output from the photoelectric conversion mechanism is electrically processed. It is necessary to provide means for controlling the amount so that the amount is proportional to the area of the area.

The present inventors investigated how to further simplify the complexity of determining the amount of C+A as described above, and as a result, the amount (R ₁ −) determined as follows was determined by using an automatic processor. It has been found that good development can be achieved even by adjusting the amount of the first replenisher to be added when one PS plate having a length L in the running direction is developed.

R ₁ −=cΣWn+aΣTn/ΣLn×L () Here, ΣWn represents the total weight of the photosensitive layer of n positive PS plates processed within a unit time, and c is the type of positive PS plate (e.g. If it is a commercially available product, the brand name)
and ΣTn is a proportional constant determined by specifying the first replenisher, and ΣTn is the positive type PS of the n sheets concerned.
Indicates the total time during which the spray operates when developing a plate, and a is a proportion determined by specifying the type of automatic developing machine, the first replenisher, and the carbon dioxide concentration in the atmosphere in which the automatic developing machine is installed. A constant is shown, and ΣLn shows the total length of the n PS plates in the running direction of the automatic processor. Further, the above ΣWn can be expressed by area when PS plates having the same photosensitive layer composition and the same coating amount per unit area are processed.

When determining the amount of the first replenisher based on the above formula, it is desirable that the size and quantity of positive PS plates to be processed be known. However, the present inventors calculated the average value (α) of cΣVn+aΣTn/ΣLn in the above formula from a large number of work results, and determined the amount of R ₁ - by using this as the proportionality constant of L. It has been found that the objects of the present invention can be fully achieved. In this case, the first
It is sufficient to add replenisher in an amount proportional to the length of the positive PS plate to be processed in the transport direction in the automatic developing machine, so the automatic developing machine is equipped with a sensing means such as a micro switch, and this detects when the automatic developing machine The first addition is carried out at a constant addition rate only during the time it is sensed that the PS plate is being moved by the feed roller.
A simple measure can be taken of adding a replenisher.

On the other hand, the quantity (R ₁ −) determined by the following equation
The object of the present invention can also be achieved by setting the amount of the first replenisher to be the amount of the first replenisher when one PS plate of area S is developed.

R ₁ −=cΣWn+aΣTn/ΣSn×S () Here, ΣSn is the number of n sheets processed within unit time.
Indicates the total area of the PS version, ΣWn, c, ΣTn and a
are synonymous with those in the formula.

Even when determining the amount of the first replenisher based on this formula, the positive type PS that is scheduled to be processed
It is desirable that the size and quantity of the plates are known, but based on a large number of work results, the above formula
The object of the present invention can be fully achieved by calculating the average value (β) of cΣVn+aΣTn/ΣSn and using this as a proportionality constant of S to determine the amount of R ₁ -. In this case, it is sufficient to add the first replenisher in an amount proportional to the area of one positive PS plate to be processed. A means for sensing the length in the width direction of the PS plate to be processed is installed together with the means, and the area of the PS plate to be processed is calculated by both of these means.
Apply an amount of the first replenisher to each area proportional to its area.
This can be carried out by adding it each time one PS plate is processed. If you use this method,
Compared to the previous replenishment method of adding the first replenisher in an amount proportional to the length of the PS plate in the transfer direction in the automatic processor, it is possible to perform replenishment with higher precision, resulting in extremely stable replenishment. Development processing is accomplished.

Yet another method for determining the amount of the first replenisher is to expand the above equation and rearrange it as the following equation: The first replenisher is added independently in an amount proportional to the amount and the time T the spray is running.

R ₁ −′=cΣWn/ΣLn×L+aT (′) Here, ΣWn, c, ΣLn, and a are all synonymous with those in the formula.

If the average value (α') of cΣWn/ΣLn in this formula' is calculated from a large number of actual work results, the automatic processor is equipped with a sensing means such as a micro switch as described above, and this by roller
The first replenisher is added at a constant addition rate for the time it is sensed that the PS plate is running, and at another constant addition rate in conjunction with the spray operation mechanism for the time the spray is operating. It is possible to add a first replenisher. The advantage of this replenishment method is that the deterioration caused by the sprayed developer absorbing carbon dioxide gas in the air is compensated for independently by the first replenisher, so it is more accurate than the formula-based replenishment method. The point is that it can be replenished.

Using the same idea, the replenishment amount can be determined using a formula with even higher accuracy. That is, the above equation is expanded and rearranged as shown in the following equation', and the first replenisher is added in an amount proportional to the area S of the PS plate and an amount proportional to the spray operation time T, independently.

R-'=cΣWn/ΣSn×S+aT (') Here, ΣWn, c, and a all have the same meanings as in the formula, and ΣSn has the same meaning as in the formula.

The first replenisher is added every time one positive PS plate is processed as described above.

On the other hand, the amount of the second replenisher in the present invention is proportional to the elapsed time, and this proportionality constant (b) is determined by the type of automatic processor, the composition of the second replenisher, and the carbon dioxide concentration in the environment in which the automatic processor is used. It is a constant determined by Therefore, once this proportionality constant b is determined, the second replenisher can be added either continuously at a constant rate or intermittently at a constant rate. That is, in the former case, it is possible to use a metering pump or chemical liquid pump, and in the latter case, it is of course possible to use a measuring cup, but it is preferable to link a timer and a metering pump so that a fixed amount can be added at fixed intervals.

Next, how to obtain the proportionality constants a, b, and c will be explained.

As mentioned above, these constants a, b, and c are based on the combination of a specific developer, first replenisher, second replenisher, and automatic processing machine, in a specific working environment, and with a specific positive PS plate. Determined in combination. Therefore, manufacturers of automatic processors and processing agents must determine in advance the constants for the combinations recommended by the manufacturer.

First, a positive PS plate (coating weight: Xg/plate) made of a specific photosensitive material is prepared. A specific developing solution with a standard loading amount of H liters is charged into a specific automatic developing machine. Thereafter, the above-mentioned positive PS plate is treated with the spray of an automatic developing machine in continuous operation.
Fuji Photo Film
Process the positive PS plate on which the PS Step Guide manufactured by Co., Ltd. has been printed and check for sensitivity loss. When the sensitivity decreases by about one step compared to the starting sensitivity, replenish the replenisher until the sensitivity returns to the starting sensitivity. When the sensitivity returns to the starting level, the process continues again, and when the sensitivity decreases by about one step, the continuous process starts again. After repeating the processing in this way and processing the sH/X plate (where s is the amount of photosensitive material per unit charge that can be processed with a specific processing agent system (approximate number)), the total amount of replenisher replenished during the running experiment. Find Mx. Let Tx be the time required for running at this time. In the same way, the same developing solution was charged in a similar automatic developing machine to an H ritter, and while the automatic developing machine was in operation, similar plates with a coating weight of X g were continuously processed in the same manner as above for sH/X plates, and the replenisher at this time was Find the total amount My. However, the time required for the above running is Ty≪
Preferably Tx. In the third run, a similar plate with a coating weight of Xg is processed in the same manner as the sH/X plate in a state in which the spray is activated only during plate processing (normal state). At this time, the spray operation time Ts, the total running time (including the spray operation time) Tz, and the total replenishment amount Mz are determined. However, Ts < Tz is desirable. Thus, when the first replenisher and the second replenisher have the same composition, the constants a, b, and c are obtained by substituting the values obtained in the above running into the following equation.

a=Ts(Mx−My)+Tx(My−Mz)
+Ty(Mz-Mx)/(Tx-Ty)(Tz-Ts) b=Tz(Mx-My)+Tx(My-Mz)
+Ty(Mz-Mx)/(Tx-Ty)(Tz-Ts) c=MyTx-MxTy/sH(Tx-Ty) When using the second replenisher with a composition different from the first replenisher, follow the steps above. While replenishing the first replenisher according to the determined constants a and c, the sensitivity is checked every time 1 to 2 hours have elapsed, and the running is performed while the sensitivity decrease due to time is compensated for with the second replenisher.Total replenishment in this case The second value is the amount Mw divided by the total running time Tw (Mw/Tw).
This is the constant b for the replenisher.

In the method of the present invention, when the development processing is interrupted for a long time, the replenishment of the second replenisher is also interrupted, and when the development is restarted, the activity of the developer in the development tank is checked and the desired activity is determined. It is advantageous to add an amount of the second replenisher such that . Specifically, we develop a positive PS plate exposed under standard conditions through a step tablet, measure the number of solid plates, and find out the degree of deterioration in the activity of the developer.
The second replenisher may be added in an amount that compensates for this deterioration.

Furthermore, as described above, in the developing method of the present invention, the activity of the developer is always maintained constant by the addition of the first replenisher and the second replenisher. It is desirable to take measures to prevent the replenisher itself from deteriorating over time. That is, it is preferable to prevent carbon dioxide gas from entering the containers that house the first replenisher and the second replenisher.

As explained above, the developing method of the present invention independently compensates for the deterioration of the developer caused by developing the positive PS plate and compensates for the deterioration of the developer over time. Because of this, the activity of the developer can always be kept constant regardless of the amount of positive PS plate processed within a unit time. Therefore, the developer stored in the developing tank of the automatic processor can be replaced without having to be replaced for a long time.
Stable development that always gives a constant development result can be performed.

Furthermore, since the developer, first replenisher, and second replenisher used in the present invention are all aqueous solutions of alkali metal silicate containing a specific amount of potassium, Since no insoluble matter is generated, and therefore the spray nozzle and filter of an automatic developing machine are not clogged, the above effects are combined with stable development processing over a longer period of time. Can be done.

Hereinafter, the present invention will be explained in more detail based on Examples. Note that "%" in the examples means "% by weight" unless otherwise specified.

Example 1 A 2S aluminum plate with a thickness of 0.24 mm was immersed in a 10% aqueous solution of tribasic sodium phosphate kept at 80°C for 3 minutes, removed, grained with a nylon brush, and then etched with sodium aluminate for about 10 seconds. do,
Desmut treatment was performed with a 3% aqueous solution of sodium hydrogen sulfate. This aluminum plate was anodized in 20% sulfuric acid at a current density of 2 A/dm ² to form an oxide film of 2.5 g/m ² .

On this support, the following photosensitive solution was applied and dried to form a photosensitive layer with a weight of 2.5 g/m ² after drying.
I got the positive PS version.

Photosensitive liquid: Esterified product of naphthoquine-(1,2)-diazide-(2)-5-sulfonic acid chloride and pyrogallol acetone resin (described in Example 1 of US Pat. No. 3,635,709). 0.63g Cresol novola lactic resin 1.98g P-t-butylphenol resin 0.05g Tetrahydrophthalic anhydride 0.15g Thymol blue 0.04g Naphthoquinone-(1,2)-diazide-(2)-4-sulfonic acid chloride 0.03g Ethylene dichloride 18g 2-methoxyethyl acetate 12g On the other hand, an automatic developing machine "1300RU" (for PS plate development, manufactured by Fuji Photo Film Co., Ltd.) with the configuration shown in Figure 1.
Co., Ltd.) was filled with 21 volumes of a stock solution with the following composition diluted 7 times (volume) with water (PH 13.10).

Stock solution formulation (developer) JIS No. 3 sodium silicate aqueous solution 332g (Contains SiO ₂ : 29.5%, Na ₂ O: 9.5%) Potassium hydroxide aqueous solution (48%) 191g N-alkyl-N,N-dihydroxyethylbetaine amphoteric Surfactant 36% aqueous solution 3.2g “Amogen K” (manufactured by Dai-ichi Kogyo Yakuhin Co., Ltd.) Organosilicon compound (antifoaming agent) 0.72g Water 688g Also, prepare a replenisher with the following composition and add 5 times the amount of water. (volume) and added as a first replenisher and a second replenisher (PH13.41) to each replenisher tank attached to an automatic processor.

Stock solution formulation (replenisher) JIS No. 3 sodium silicate aqueous solution 238g Potassium hydroxide aqueous solution (48%) 328g Water 645g Adjust the development temperature to 35℃ and develop the positive PS plate through an automatic processor for 50 seconds. I adjusted it as follows. 30 sheets of the positive PS plate (the above) of the chrysanthemum plate image-exposed with the automatic developing machine prepared in this way were
Development processing was carried out at appropriate time intervals over a period of time. At this time, 390 ml of the second replenisher was added to the developer every hour after the development start time, and 37 ml of the first replenisher was added every time one positive PS plate was developed. It was found that the development results obtained by processing in this manner were almost the same, and that the developer solution maintained almost the same development activity during the development process. Each PS plate has a step tablet (the optical density of the first stage is 0.10 and the density difference of one stage is
0.15 and has 15 steps. ), and all differences in the number of solid steps were within one step.

After this development process was completed, the developing solution and replenisher were left in the automatic developing machine for 18 hours.
After that, when I started developing again, I processed the PS plate with the step tablet printed on it, and found that the developing activity had decreased, so I added 3.4 liters of replenisher.
was added and the development process was started again. This process was repeated for a total of 6 days, but
The difference in the number of solid steps between the first development process and the sixth day development process was within ±1 step. It was confirmed that the effects of the present invention were sufficiently exhibited over a long period of time, and the objective was achieved. Note that the potassium content in the developer and replenisher in this case is 62.6% and 62.6%, respectively, on a gram atom basis.
The ratio of silicic acid content to alkali metal [SiO ₂ ]/[M] was 0.61 and 0.33, respectively. Also, the amount of first replenisher added is calculated according to the formula, in which constants a and c are each 2.5
ml/min, 16 ml/g. Further, even after the development process was continued for 6 days, no clogging of the nozzle of the automatic processor was observed, and no insoluble matter was observed in the developer.

Example 2 As in Example 1, using an automatic developing machine "1300RU", solutions with the following formulations were prepared as a developer stock solution and a replenisher stock solution.

Stock solution formulation JIS No. 3 Sodium silicate aqueous solution 497g Potassium hydroxide 48% by weight aqueous solution 272g Amphoteric surfactant (used in Example 1)
3.2g Organosilicone antifoaming agent 0.72g Water 760g Dilute the above stock solution to 7 times (volume) with water and add it to the automatic developer as 21 developer (PH13.07).In each replenisher tank, A stock solution with the above composition was diluted 3 times (volume) with water (PH 13.40). The heat insulator was adjusted so that the temperature of the developer was 25°C, and the operating conditions were set so that the PS plate development time was 40 seconds, and development processing was started.

In this example, the positive PS plate used in Example 1 was used. However, the size and number of sheets were 1310 mm x 1050 mm (size A), 30 sheets 1003 mm x 800 mm (size B), and 100 sheets 650 x 525 mm (size C) 80 sheets. The automatic developing machine is equipped with a mechanism that uses a micro switch to measure the length of one side of each PS plate being processed. of the first replenisher was allowed to be added into the developer solution. In the case of 40 seconds development in this example, for the length of one side of the PS plate,
The amount of first replenisher added per 0.892 m was 33 ml. Based on this standard value, in the case of size A treatment, the amount of replenisher is 48.5ml, and in the case of size B,
It was 29.6ml, and in the case of size C it was 19.4ml. or,
As the second replenisher, 840 ml of the second replenisher was replenished every two hours after the start of the development process.

Under the processing conditions described above, various sizes were mixed and processed irregularly, but the processing was carried out either continuously or intermittently for 22 hours after the start of the development process. Even at that time, the difference in the number of solid steps between images produced by step tablets printed on developed printing plates was within one step.
In this example as well, the effects of the present invention were fully observed. In this case, the potassium content in the developer and replenisher is 61% on a gram atom basis.
The ratio of silicic acid content to alkali metal [SiO ₂ ]/[M] was 0.585. The amount of the first replenisher added was calculated according to the formula, and the constants a and c in this case were 2.5 ml/min and 14 ml/g, respectively.

Example 3 In the same manner as in Example 1, except that the following stock solution formulation was diluted to 7 times the volume with water as the developer.
21 was prepared, 210 g of potassium pyrophosphate was dissolved therein, and the mixture was poured into the developing tank of an automatic developing machine.

Sodium metasilicate nonahydrate 360g JIS No.3 Sodium silicate 66g Amphoteric surfactant (used in Example 1) 3.2g Organic silicone antifoaming agent 0.72g Water 784g Also, the above composition as the first and second replenisher The stock solution was diluted to 3 times (volume) with water and 23.3g of potassium pyrophosphate was added to it, and a Kikuzen size (1003mm x 800mm) positive PS plate 80 plate was heated for 6 hours. and process it at appropriate time intervals,
Each time one plate was processed, 25 ml of the first replenisher was added. Further, the developer was replenished with 400 ml of the second replenisher every hour after the start of the development process.
The development results obtained in this way showed that the change in the number of solid steps of the step tablets printed on each PS plate was within one step, indicating that the processing was very stable, and the developing solution was used to develop almost the same color throughout the process. It was confirmed that the activity was maintained.

In this case, the potassium content in the developer and replenisher was about 24% on a gram atom basis. Also, the amount of the first replenisher added is calculated according to the formula, and in this case, the constants a and c are each 2.2 ml/
min, 12.5 ml/g. Further, when this processing fatigue solution was left as it was in an automatic processor for 4 days, no generation of muddy precipitates was observed.

Example 4 Automatic developing machine “1300U” (for PS plate development, manufactured by Fuji Photo Film Co., Ltd.) with the configuration shown in Figure 1.
The stock solution formulation used in Example 2 was diluted with water to
21 times the amount was diluted and used as a developer.
In addition, a stock solution with the same composition was diluted with water to 3 times (volume) to prepare a first replenisher solution and a second replenisher solution. Positive type that passes through an automatic developing machine with the developing temperature adjusted to 25℃
The development time for the PS version was adjusted to 40 seconds.
The positive PS plate (used in Example 1) image-exposed using the automatic processor thus prepared and the following positive PS plate were prepared in the quantities shown below at appropriate time intervals over a period of 10 hours. It was developed and processed.

The positive PS version was created as follows.

A 2S aluminum plate with a thickness of 0.24 mm was degreased by immersing it in a 10% aqueous solution of tribasic sodium phosphate kept at 80℃ for 3 minutes, grained with a nylon brush, and then etched with sodium aluminate for about 10 seconds.
Desmut treatment was performed with a 3% aqueous solution of sodium hydrogen sulfate.

On this support, the following photosensitive solution was applied and dried to form a photosensitive layer with a weight of 2.5 g/m ² after drying.
I got the positive PS version.

Photosensitive liquid: Esterified product of naphthoquinone-(1,2)-diazide-(2)-5-sulfonic acid chloride and pyrogallol acetone resin (described in Example 1 of US Pat. No. 3,635,709). 0.63g Cresol novola lactic resin 1.98g pt-butylphenol resin 0.05g Tetrahydrophthalic anhydride 0.15g Thymol blue 0.04g Naphthoquinone-(1,2)-diazide-(2)-4-sulfonic acid chloride 0.03g Ethylene dichloride 18g 2-methoxyethyl acetate 12g Positive PS plate 1310mm x 1050mm (A size) 15th edition/day 1003mm x 800mm (B size) 30th edition/day Positive PS plate 1310mm x 1050mm (A size) 15th edition/day 1003mm x 800mm (B size) 20 plates/day 700mm x 550mm (C size) 30 plates/day For replenishment, each time each plate is processed, an amount of replenisher (50ml/m ² ) proportional to its area is added as the first replenisher. did. That is, 62ml for A size plate, B
For size plates, 40 ml was added, and for C size plates, 19 ml were added. Furthermore, 400 ml of the second replenisher was replenished every two hours after the start of the development process. After completing this development process, the developer and replenisher were left in the automatic processor overnight (14 hours).
I left it alone. As a result, the activity of the developer decreased, so 2.5 liters of the replenisher was added and the development process was started again, processing the same amount of plates as the previous day. Like this 2
It was confirmed that the effects of the present invention were sufficiently exhibited and the objective was achieved even when the treatment lasted for several days.

Note that the amount of the first replenisher added is calculated according to the formula, and the constants a and c in this case are respectively
It was 2.5 ml/min and 16 ml/g.

[Brief explanation of the drawing]

FIG. 1 is a schematic cross-sectional view of an automatic processor.

Claims (1)

[Scope of Claims] 1. A method of imagewise exposing a positive-working photosensitive lithographic printing plate having a photosensitive layer made of an o-quinonediazide compound, and then developing it with a developer made of an aqueous solution of an alkali metal silicate, comprising: (1) ) A first replenisher consisting of an aqueous solution of an alkali metal silicate having a higher alkaline activity than the alkali activity of the developer is added to the positive type. (2) an alkali metal silicate having an alkali activity higher than that of the developer; A positive-working photosensitive method comprising adding a second replenisher consisting of an aqueous salt solution to the developer (a) continuously in a fixed proportion, or (b) intermittently in fixed quantities hourly. In a method for developing a lithographic printing plate, each of the developer, the first replenisher and the second replenisher contains at least 20% of the gram atoms of alkali metal present therein. A developing method characterized by containing potassium. 2. A transport means for transporting a positive photosensitive planographic printing plate, a nozzle pipe for injecting a developer onto the photosensitive layer of the positive photosensitive planographic printing plate transported by the transport means, a developing tank, and the interior of the developing tank. The development is performed by an automatic developing machine comprising a developer supply means for supplying a developer to the nozzle pipe,
The first replenisher includes (a) an amount proportional to the length or area of the image-exposed positive-working photosensitive lithographic printing plate in the direction of transport by the transport means;
(b) The developer is added separately in two independent amounts proportional to the time during which the developer is injected from the nozzle pipe.
Development method described in section. 3. The first replenisher is added in an amount represented by the following formula or formula each time one positive-working photosensitive lithographic printing plate is processed. development method. cΣWn+aΣTn/ΣLn×L () cΣWn+aΣTn/ΣSn×S () Here, ΣWn represents the total weight of the photosensitive layer of n positive-type photosensitive lithographic printing plates that are developed within a unit time, and c is the positive-type Indicates a proportionality constant determined by the type of photosensitive lithographic printing plate and the first replenisher, and ΣTn is the total spray operation required to develop the n positive photosensitive lithographic printing plates. time, a is a proportionality constant determined by specifying the type of automatic processor, the first replenisher, and the carbon dioxide concentration in the atmosphere in which the automatic processor is installed, and ΣLn is Indicates the total length of the positive photosensitive planographic printing plates in the running direction in the automatic processor, ΣSn indicates the total area of the n positive photosensitive planographic printing plates, and L and S respectively The length and area of each positive-working photosensitive lithographic printing plate in the running direction are shown. 4. The first replenisher is added in an amount determined by the following formula 'or formula' each time the positive-working photosensitive lithographic printing plate is processed. The developing method according to scope 2. cΣWn/ΣLn×L+aT (') cΣWn/ΣSn×S+aT (') Here, ΣWn, c, ΣLn, a, ΣSn, L and S are all synonymous with those in formula and, and T is the Shows the time during which the spray is activated when a positive-working photosensitive lithographic printing plate is processed. 5 The developer is [SiO ₂ ]/[M] (however, [SiO ₂ ]
represents the content of SiO ₂ in a unit volume expressed in gram molecules, and [M] represents the content of alkali metal in a unit volume expressed in gram atoms. ) is 0.5 to 0.75, and the concentration of SiO ₂ is 1 to 4% by weight based on the total weight, and both of the first and second replenishers are [SiO ₂ ] / [M] (where [SiO ₂ ] and [M] are the same as in the above case) is an aqueous solution of an alkali metal silicate with 0.25 to 0.75, Claims 1, 2, and 3 Or the developing method described in Section 4.