JPH01310356A - Cleaning liquid and cleaning method for automatic developing machine for engraving of planographic printing plate - Google Patents

Abstract

PURPOSE:To facilitate the cleaning of an automatic developing machine by incorporating a fluorine compd. selected from hydrofluoric acid or hydrofluoride into the cleaning liquid. CONSTITUTION:At least one kind of the fluorine compd. selected from the hydrofluoric acid or hydrofluoride is incorporated at 0.005-5wt.% into the clean ing liquid for cleaning the automatic developing machine for engraving of planographic printing plates and the members thereof. The sufficient cleaning effect is not obtainable if the concn. of the fluorine compd. is below said range and the cleaning effect is satd. and there is a need for taking care for the toxicity thereof into consideration at the concn. higher than said range. Further, an org. acid is preferably incorporated into this detergent in order to maintain the pH at acidity and to intensify the detergency thereof. The cleaning of the automatic developing machine is thereby facilitated and the corrosion of the members by the cleaning liquid is suppressed to a lower level.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an improved cleaning solution for an automatic developing machine for planographic printing plate making and a cleaning method using the same.

[Conventional technology and its problems]

When developing a large quantity of photosensitive lithographic printing plates (hereinafter referred to as PS plates), an automatic developing machine is generally used. This automatic developing machine generally consists of a device for transporting the PS plate, a developer tank, and a spray device, and while the exposed PS plate is transported horizontally, the developer pumped up by a pump is sprayed from a spray nozzle to develop it. It is something to be processed. Other methods are also known in which the PS plate is immersed and conveyed in a developing tank filled with a developing solution using a submerged guide roll or the like.

In this type of automatic processor processing, the developer is recycled repeatedly from an economical point of view, so the concentration of the photosensitive layer components eluted into the developer gradually increases, and as a result, the concentration of the photosensitive layer components dissolved in the developer increases. Dirt and sludge are generated and deposited around the developer tank and in the piping of the developer EI ring system, causing various problems.

Additionally, as a developing solution for a PS plate having a photosensitive layer containing an 0-quinonediazide compound as a main component, an alkaline aqueous solution of silicate is often used to impart hydrophilicity to the non-image area after development. However, such developer tends to precipitate as water-insoluble silica in the spray pipe of an automatic processor, in and around the developer tank due to drying or splashing when the developer is stopped, and this problem is simply an aesthetic problem. Instead, it caused various problems.

As a method to solve the drawbacks of the above-mentioned method of circulating and reusing a large amount of developer using an automatic developing machine, a fixed amount of new developer is supplied to the exposed surface of the exposed PS plate for development. After that, the developer is removed and the developer is discarded (
(hereinafter referred to as the disposable development method) was published in Japanese Patent Application Laid-Open No. 48-2950.
No. 5, Japanese Unexamined Patent Publication No. 55-32044, and U.S. Pat. No. 4,222,656 disclose that even in this type of automatic developing machine, stains occur during long-term use. I couldn't escape.

Furthermore, when processing a large number of PS versions over a long period of time,
A developer replenishment method such as that disclosed in Japanese Patent Application Laid-open No. 58-95349 has been proposed, but dirt accumulates on the sensor that detects the capacity of the developer, causing it to no longer show accurate values and becoming unstable. In some cases, accurate refilling could not be performed.

In order to resolve the above problems, it will take one week to
Processing chemicals such as developer solution have been collected from automatic processors every month, and the automatic processors have been washed with water. However, as the period of use of the automatic developing machine increases, the dirt becomes difficult to remove, and a lot of time is spent cleaning it.Especially when the developing solution consists of an alkaline aqueous solution of silicate, the precipitated silica is removed by water. It was insoluble and water washing was quite difficult.

Therefore, cleaning agents for automatic processors containing strong acids such as sulfuric acid and hydrochloric acid have been used in some cases, but even these agents have insufficient cleaning properties. Moreover, since the pH of these cleaning agents is less than 1, there is also the problem that stainless steel developer tanks and spray pipes are corroded.

[Problem to be solved by the invention]

Therefore, an object of the present invention is to provide a cleaning agent and a cleaning method that facilitate the cleaning of an automatic processor for PS plates, and more specifically, a cleaning agent and a cleaning method that do not attack the parts of the automatic processor such as stainless steel. The goal is to provide the following.

[Means to solve the problem]

As a result of intensive studies by the present inventors to solve the above problems, the composition contains a trace amount of hydrofluoric acid or a salt thereof. The inventors have discovered that a cleaning liquid is extremely effective in achieving the above object, and have completed the present invention.

That is, the present invention contains 0.005 to 5% by weight of at least one fluorine compound selected from hydrofluoric acid or fluorine salts.
The present invention provides a cleaning liquid for cleaning an automatic developing machine for planographic printing plate making and its members, which is characterized by containing:

The present invention also provides 0.005 to 5% by weight of at least one fluorine compound selected from hydrofluoric acid or fluorine salts.
and at least one organic acid,
The present invention provides an automatic developing machine for planographic printing plate making and a cleaning liquid for cleaning its members.

The present invention is further characterized in that the above-mentioned cleaning liquid is used.
The present invention provides an automatic developing machine for planographic printing plate making and a method for cleaning its members.

Among the fluorine compounds that characterize the cleaning solution of the present invention, examples of hydrofluoric acid include hydrofluoric acid itself, hexafluorozirconic acid, hexafluorovanadic acid, tetrafluorotungstic acid, hexafluorotitanic acid, and hexafluorocobaltic acid. Free hydrofluoric acid contained in hexafluoroboric acid, tetrafluorozinc acid, and the like is used.

Among these, hexafluorozirconic acid and hexafluoroboric acid are safe and preferred in terms of handling. Furthermore, examples of the fluoride salt include sodium fluoride, potassium fluoride, lithium fluoride, calcium fluoride, magnesium fluoride, ammonium fluoride, potassium hydrogen fluoride, sodium hydrogen fluoride, and ammonium hydrogen fluoride.

The preferred concentration of fluorine compounds in the cleaning agent is 0.005-5
It is % by weight, more preferably 0.01 to 1% by weight. If the concentration is lower than this, the cleaning effect will not be sufficient.
Furthermore, if the concentration is higher than this, the cleaning effect will be saturated, and it is necessary to pay attention to its toxicity.In particular, a large amount of rinsing water will be required after cleaning, and the cost for processing the waste liquid will increase.

Further, the cleaning agent of the present invention may contain an acidic substance such as an organic acid or an inorganic acid in order to maintain the pH at an acidic level and strengthen the cleaning power. However, in order to prevent corrosion of stainless steel, the pH is preferably 1 or more, and for this purpose it is advantageous to use an organic acid.

Further, by using an organic acid in combination, strong cleaning power can be provided even if the concentration of fluoride is lowered. Organic acids used for this include oxalic acid, citric acid, acetic acid, hydroxyacetic acid, tartaric acid, maleic acid, malic acid, succinic acid, adipic acid, azelaic acid, cepacic acid, pimelic acid, levulinic acid, lactic acid, and geltaric acid. , malonic acid, fumaric acid, itaconic acid, propanetricarboxylic acid, formic acid,
Examples include butyric acid, humic acid, phytic acid and 5-sulfosalicylic acid.

Also, 3.3-diphosphonopentane dicarboxylic acid, aminotri(methylenephosphonic acid), methylene diphosphonic acid, l-hydroxyethane 1.1=diphosphonic acid, 2
-amino-2-methyl-1-hydroxypropane-1,
1-diphosphonic acid, 2-phosphonobutanetricarboxylic acid-1,2,4 nitrilotriphosphonic acid, N-carboxymethylamino-N,N-di(methylenephosphonic acid) and hexamethylenediamine-tetra(methylenephosphonic acid), etc. Organic phosphonic acids are also used.

Further inorganic acids include hydrochloric acid, sulfuric acid, nitric acid, phosphoric acid, chloric acid, perchloric acid, sulfurous acid, thiosulfuric acid, peroxysulfuric acid, nitrous acid, phosphorous acid, metaphosphoric acid, pyrophosphoric acid, vanadic acid, and tungstic acid. used.

Among these acidic substances, organic acids are particularly preferred because they cause less corrosion of stainless steel. Particularly preferred is oxalic acid,
It is citric acid. The amount of these acidic substances added to the cleaning solution is preferably 0.01 to IO% by weight, more preferably 0.5 to 5% by weight.

A surfactant, an organic solvent, a dye, and an antifoaming agent can be further added to the cleaning solution of the present invention.

Among these, surfactants are effective in promoting the cleaning action, and nonionic surfactants, anionic surfactants, and the like are preferably used. Preferred nonionic surfactants include polyoxyethylene alkylphenyl ether and polyoxyethylene polyoxypropylene block polymer.

The preferred amount of surfactant added is:
It is 0.0001 to 5% by weight, and a particularly preferable range is 0.0001 to 5% by weight.
．． 0.005 to 1% by weight.

The cleaning solution of the present invention can be prepared as a concentrated solution and diluted to an appropriate concentration before use.

A method for cleaning a 28-plate automatic processor using the cleaning solution of the present invention is to drain the developer, wash with water if necessary, and then charge the cleaning solution into the developing section of the automatic processor at a temperature of lO A method is used in which the cleaning solution is circulated at a temperature of 10 to 60 minutes at a temperature of 10 to 45 degrees Celsius, preferably 20 to 35 degrees Celsius. In addition, with this method, members that are difficult to soak in the cleaning liquid or members that have a particularly large accumulation of dirt can be removed and cleaned. In particular, dirt may stick to the replenishment control sensor of an automatic processor equipped with the replenishment device described in JP-A-58-95349, causing replenishment abnormalities. By immersing it in the cleaning solution for about 20 minutes, dirt can be thoroughly removed and replenishment control can be performed accurately.

Further, the cleaning liquid of the present invention can be suitably used not only for cleaning the developing bath of an automatic developing machine, but also for cleaning each bath constituting the automatic developing machine, such as a water washing bath, a rinsing bath, and a protective gum bath.

〔Example〕

Hereinafter, the present invention will be explained in more detail with reference to Examples. However, the present invention is not limited in any way by the following specific examples.

Example 1 A aluminum plate for ISS material treated in a grain chamber was immersed for 1 minute in a 2% by weight hydroxide solution kept at 40°C to perform etching treatment. Next, the pure aluminum surface was exposed by immersing it in a water washer sulfuric acid-chromic acid mixture for about 1 minute. This was immersed in 20% by weight sulfuric acid kept at 30°C, anodized for 3 minutes at a DC voltage of 15V and a current density of 2A/dm, washed with water, and dried. A photosensitive composition solution of the composition 2
g/m' (dry weight), dry and P
I got the S version.

Methyl ethyl ketone...50 g Cyclohexanone...40 g The positive PS plate thus obtained was exposed through a transparent film for 60 seconds using a 3KH metal halide lamp. did.

Next, development processing was performed using an automatic developing machine, a developer, and a rinsing solution as shown below.

(1) Automatic processor Equipped with a developing bath and a subsequent rinsing bath, a drive device that horizontally transports the exposed PS plate, and a device that circulates the processing solution of each processing bath from storage tank to pump to spray nozzle to storage tank. This is an automatic developing machine having a replenishing device for the developing bath, and the developing bath storage tank has a mechanism for discharging excess processing liquid through an over 70-.

In this case, to replenish the developer, place a PS in the middle of the developer bath.
A sensor is provided to measure the degree of elution of the photosensitive layer in the non-image area of the plate photosensitive layer, and a certain amount of developer replenisher is automatically replenished when the degree of elution falls to a predetermined level.

(2) Developer Solution The following developer solution stock solution was diluted 7 times with water, and 211 was added to the above developer bath. The pH of the developer was 13.9.

JIS No. 3 silicate) IJum aqueous solution...3
32g potassium hydroxide (48% by weight aqueous solution)...19
1g pure water
...688 g (3) Based on the measured value of the developer replenisher replenishment detection sensor, a replenisher stock solution with the following composition and water were mixed at a ratio of 1:4, and the required amount was replenished.

(Composition) JIS No. 3 silicate) IJum aqueous solution...2
38g potassium hydroxide (48% by weight aqueous solution)...3
28g pure water ・
...645 g (4) Rinse liquid containing surfactant A rinse liquid (pH approximately 6.0) 8β having the following composition was charged into a rinse bath. The rinse bath was replaced with fresh solution every week.

(Composition) Phosphoric acid (85% by weight aqueous solution) 2.4
g Sodium hydroxide ・・・・・・・・・1
g water
...1003mm x 800 under conditions of 985 g or more
When processing 35 mm-sized PS plates every day for 3 weeks, the capacity of the developer decreased, so the developer was replaced with a new solution and the same processing was continued. One round was three weeks long, and after the 10th round, dirt became noticeable in the developing bath. Additionally, the replenishment detection sensor tended to become somewhat unstable, probably due to dirt attached to it. Therefore, automatic processor cleaning solution A having the following composition was prepared. pH is 2
．． It showed 0.

(Composition) Oxalic acid...=20 g Pure water...1.
After draining the developer from the 000g automatic developing machine, add approximately 2.0 g of water.
01, pre-rinsed with water, drained the washing water, filled the 201 developing bath with the above-mentioned cleaning solution A, and heated it at room temperature for about 30 min.
It circulated for minutes. After collecting the cleaning liquid A, it was washed with about 20 liters of water. As a result, the stains adhering to various parts of the developing bath were dissolved and removed.

Also, during this cleaning process, remove the replenishment detection sensor and add it to the cleaning solution container in a plastic container for approximately 20 minutes at room temperature.
After soaking for a minute, a clean stainless steel surface appeared. After washing the sensor with water, we measured its electrical resistance.
The resistance value was lower than before cleaning, and the resistance value was the same as that of an unused sensor.

Comparative Example-1 Cleaning liquid B having the following composition was prepared. The pH was below 1.0.

(Group or) Phosphoric acid (85%) 70g
Hydrochloric acid (36%) ・・・・・・・・・54g Pure water ・・・・・・1.0
When the same process as in Example 1 was carried out except that cleaning liquid B was used instead of cleaning liquid A, the stains on the automatic developing machine could not be completely removed by circulating cleaning for about 30 minutes.
There was quite a bit left. Then, when circulating cleaning was continued for about 30 minutes, the amount of dirt adhered to the surface decreased slightly, but it was still not completely cleaned.

However, the stainless steel part of the developing bath began to turn brown due to corrosion from the cleaning agent, so cleaning was discontinued. Next, the replenishment detection sensor was immersed in the cleaning solution at room temperature for about 20 minutes, but the removal of the stains adhering to the stainless steel was insufficient and the resistance value after cleaning could not be restored to the value of the unused sensor.

Example 2 A cleaning liquid C having the following composition was prepared. p) l showed 2.5.

Example 1 except that the above cleaning liquid C was used instead of cleaning liquid A.
When the same treatment as in Example 1 was performed, the same cleaning effect as in Example 1 was obtained.

(Effects of the Invention) According to the present invention, it is possible to easily clean an automatic developing machine, and corrosion of members caused by cleaning liquid can be suppressed to an extremely low level.

Furthermore, by using an organic acid in combination, it is possible to further reduce the corrosivity of the cleaning liquid to components without reducing the cleaning power.

Claims (4)

[Claims] (1) An automatic developing machine for lithographic printing plate making, which is characterized by containing 0.005 to 5% by weight of at least one kind of fluorine compound selected from hydrofluoric acid or fluorine salts, and its members. Cleaning liquid for cleaning. (2) Lithographic printing characterized by containing 0.005 to 5% by weight of at least one fluorine compound selected from hydrofluoric acid or fluorine salts and at least one organic acid. A cleaning liquid for cleaning automatic plate-making machines and their parts. (3) A method for cleaning an automatic developing machine for planographic printing plate making and its members, characterized by using the cleaning liquid according to claim 1. (4) A method for cleaning an automatic developing machine for planographic printing plate making and its members, characterized by using the cleaning liquid according to claim 2.