JPH02165152A - Device applying photosensitive liquid for manufacturing photosensitive printing plate - Google Patents

Abstract

PURPOSE:To prevent a bubble fault and an application stripe fault, and to contrive the obviation of uneven thickness with the lapse of time by using a blade made of plastic as the scraping blade of a photosensitive liquid which is extruded from a nozzle and adheres to a metaling roll so as to be opposed to an applicator roll. CONSTITUTION:When in an extruding nozzle 20, a photosensitive liquid L from a tank 7 is fed forcedly through a filter 9 by a pump 8, the photosensitive liquid flows out from a slit, extending over the whole width of a pocket. The photosensitve liquid L allowed to flow out is applied to an applicator roll 2, and thereafter, transferred to a supporting body B. That is, when the photosensitive liquid is supplied to the applicator roll by the extruding nozzle 20, as long as the photosensitive liquid is supplied at constant supply speed, not only the fluctuation of primary film thickness can be prevented, but also the factor of generation of a bubble is eliminated completely, therefore, a bubble fault can be prevented. In this case, by using a doctor blade 6 made of plastic, sufficient flexibility and elasticity of some extent can be given, therefore, the doctor blade 6 adheres well to the metaling roll 4, and a stripe fault can be prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to an apparatus for applying a photosensitive liquid in the production of photosensitive printing plates.

[Conventional technology]

Photosensitive negative printing plates are generally produced by coating a photosensitive composition on a support such as an aluminum plate, irradiating active light such as ultraviolet rays through a negative image, and polymerizing or crosslinking the irradiated areas. The areas that are not irradiated with light are insolubilized in a developing solution and eluted into the developing solution, and each area is divided into an image area that repels water and receives oil-based ink, and a non-image area that receives water and repels oil-based ink. It can be obtained by

In this case, the photosensitive composition is particularly suitable for negative type 2
In the 8th edition, diazo resins such as the condensate of P-diazodiphenylamine and formaldehyde have been widely used.

In addition, when quinone diazos are used as a photosensitive composition, their solubility in an aqueous alkaline solution is increased by irradiation with actinic rays, and the unexposed areas can be left as a resist image by alkaline development after exposure, resulting in positive photosensitivity. You can get the print.

In any case, when manufacturing this type of printing plate, 1.
Pre-treated supports such as grained cloth, electrolytic polishing, anodizing, etc.
It is usually obtained by applying a photosensitive solution containing the photosensitive composition to an aluminum plate.

Normally, the reverse roll coating method shown in FIG. 3 is mainly used to apply this photosensitive liquid.

That is, the photosensitive liquid is picked up by the applicator roll 2, which is partially absorbed by the photosensitive liquid in the vat 1, and is transferred to the surface of the support B, which is conveyed by the backup roll 3 facing the applicator roll 2. After transfer coating is applied, excess photosensitive liquid is wiped off using a metering roll 4, and the photosensitive liquid (2) is returned to the vat 1 through a pan 5.

6 is a tractor blade made of metal, for example, phosphor bronze, and is used to scrape off the photosensitive fiL, which has not yet dripped and is attached to the metaling roll 4 (=), onto the pan 5.J:. The primary film thickness on the support B is determined by mainly determining the gap between the applicator roll 2 and the support B and the rotation speed (speed) of the applicator crawl 3 relative to the conveyance speed of the support B. The desired final film thickness is obtained by making it thicker than the desired final film thickness (liquid film thickness) and then applying the metering roll 4 to the coating liquid while setting the position j7.Therefore, the applicator roll 2 The metering roll 4 acts as a film thickness control means for obtaining the final film thickness for the primary film If of the photosensitive liquid to be applied.

[Problem to be solved by the invention]

However, in the conventional coating method described above, since the vat 1 is intermittently replenished with the photosensitive liquid (7), the liquid level of the photosensitive liquid (2) fluctuates, and the liquid level may be high or low. The constant film thickness fluctuates. Especially when the liquid level is high,
Due to excessive coating amount, flow of the primary film was observed on the support B, and even if the film thickness was controlled by the metering roll 4, the thickness did not increase in the width direction of the support B (or in the direction of flow in some cases). This causes unevenness.

Note that the amount of photosensitive liquid picked up by the applicator roll, and therefore the film thickness b w of the same low route, is usually (1)
Given the expression.

(77: viscosity, lJ: l: 7-le circumferential speed, ρ: density of photosensitive liquid, σ: angle between the liquid level and the tangent to the roll there)
Therefore, if the above α is different, that is, if there is a change in the liquid level, - the igneous thickness will change.

On the other hand, a surfactant, particularly a fluorine-containing surfactant, is often added to this type of photosensitive liquid as a coatability improving agent. Particularly when a surfactant is added, the photosensitive liquid tends to fluidize and foam in the vat 1 as the applicator roll 2 rotates. This foam is applied to applicator roll 2.
The photosensitive liquid is picked up together with the photosensitive liquid and applied to the supports 8, resulting in a coating failure.

In addition, in the metering roll 4, the photosensitive liquid still adhering to the surface of the metal ring 4 is scraped off with a metal doctor blade 6 in order to ensure durability. Due to reasons such as insufficient flexibility and pliability of manufactured doctor blades, the doctor blade 6 does not come into uniform contact with the metering roll 4 in the width direction of the support, resulting in uneven scraping. As a result, coating streaks are formed on the final coated surface.

SUMMARY OF THE INVENTION Therefore, the main object of the present invention is to provide a coating device that is free from bubble failures and coating streak failures, has excellent coating properties, and can also eliminate uneven thickness over time.

[Means to solve the problem]

The above-mentioned problem is to apply a primary film thickness of a photosensitive liquid on a support that is equal to or greater than the final film thickness by transfer coating using an applicator roll facing the printing plate support, and then scraping the coated photosensitive liquid with a metaling roll facing the printing plate support. In the drop coating device; an extrusion nozzle is provided facing the applicator roll to supply the photosensitive liquid to it while pushing it out from the nozzle, and a blade for scraping off the photosensitive liquid adhering to the metaling roll R7I is provided with a plus deck. This can be solved by using a manufactured blade.

[For production]

According to the invention, if the photosensitive liquid is supplied to the applicator roll by means of an extrusion nozzle, as long as the photosensitive liquid is fed at a constant feed rate, - fluctuations in the igneous thickness can be prevented; Since such bubble generation factors are completely eliminated, bubble failures can be reliably prevented.

Furthermore, since the doctor blade is made of plastic, it can be provided with sufficient flexibility and a certain degree of elasticity, so that the doctor blade can be brought into close contact with the metering roll, thereby preventing streak failure.

[Specific structure of the invention]

The present invention will be explained in more detail below with reference to a specific example shown in FIG.

In the present invention, the extrusion nozzle 20 supplies the photosensitive liquid to the applicator roll 2 at a constant supply rate over time.

As an example of the structure of the extrusion nozzle 20, as shown in FIG.
B is aligned, a narrow slit 22 is secured in the coating example, this slit 22 is communicated with the pocket 23, an inflow hole 24 for the photosensitive liquid is formed in the blur 23, and the end of the head 21A, 21B is placed. end plate 25A, 2
I guessed 5B.

In this extrusion nozzle 20, when the photosensitive liquid from the tank 7 is pumped through the filter 9 by the pump 8,
The photosensitive liquid flows out from the slit 22 while spreading over the entire width of the pocket 23.

The flowed out photosensitive liquid is applied to the applicator roll 2 and then transferred to the support B. Therefore, as long as the pump 8 supplies the photosensitive liquid to the extrusion nozzle 20 at a constant supply rate, the igneous thickness remains constant.

Here, the filter 9 has the function of trapping bubbles, if any, along with dust in the photosensitive liquid. Lo is a new photosensitive solution for replenishment.

On the other hand, in the present invention, the doctor blade 6 is made of plastic. Specific materials include polyethylene, polypropylene, acrylic, polycarbonate, vinyl chloride, etc., but polyethylene resin is particularly preferred. Any material may be used as long as it is made of plastic; therefore, a laminate with metal materials or the like may also be used. The thickness of the doctor blade is preferably 2n or less in terms of adhesion.

In the present invention, as the photosensitive liquid, all conventionally known photosensitive liquids for photosensitive printing plates can be used. This photosensitive liquid requires a photosensitive resin and a binder, and if necessary, coloring materials, alkyl ethers, coating improvers such as fluorosurfactants and nonionic surfactants, plasticizers, and photosensitive resins. It is prepared by adding a curing agent, etc. and dissolving it in a solvent.

The viscosity of the photosensitive liquid to which the method of the present invention is effectively applied (measured at 25°C with a B-type viscometer) is preferably 500 cp or less, and when the photosensitive liquid contains a surfactant and is foamable. In this case, the effects of the present invention become more pronounced.

The amount of the surfactant added is preferably 0.1 to 5 parts by weight in the photosensitive liquid. Specific examples of the surfactant include rF manufactured by 3M Co.
C-430J (Fluorine surfactant) “Megafac F-171, F-173, F-” manufactured by Dainippon Ink Chemical Co., Ltd.
815, F-1427", Asahi Glass "Surflon S-
112,S-113,5-121゜3-131.3-1
45J, Shin Akita Kasei “F-TOP EF-101, 102
, 121, 122" fluorine-based surfactant), "Span 65" manufactured by Kao Madras (sorbitan triacetate)
, "Emulgen 404J (polyoxyethylene oleyl ether),""Emulgen 905J (polyoxyethylene nonyphenol ether), etc."

On the other hand, it is preferable to use an aluminum plate as the support for the printing plate. In nitric acid or an electrolytic solution containing nitric acid as the main component,
Alternatively, the surface may be grained by electrolytic roughening in hydrochloric acid or an electrolytic solution containing hydrochloric acid as a main component, and preferably further subjected to surface treatment such as anodizing treatment and, if necessary, sealing treatment.

After applying the photosensitive liquid, it undergoes inspections such as drying, cutting, and surface inspection. The obtained photosensitive printing plate blank is then adhered to a film, imagewise exposed by irradiation with actinic light, and developed with a developer, leaving an image area to form the final printing plate.

〔Example〕

Next, examples will be shown to clarify the effects of the present invention.

After degreasing an aluminum laminated J plate having a thickness of 0.24 μm, it was electrolytically polished with an aqueous hydrochloric acid solution 7 and desmutted with caustic soda. Next, a scratch oxidation treatment and a hot water sealing treatment were performed in an aqueous sulfuric acid solution to obtain an aluminum plate for a lithographic printing plate.

Next, the following photosensitive liquids were coated and dried on this aluminum tentatively using the coating apparatus shown in Figs. 1 and 2, respectively.
A photosensitive lithographic printing plate sample was obtained.

Photosensitive liquid> ・Pyrogallol acetone resin (weight average molecular weight 1600
) and naphthoquinone (1,2) diazide 5-sulfonyl chloride (condensation rate: condensation rate of hydroxyl group 33 mol%) 2 parts by weight mixed cresol (phenol: m-cresol diP-
Cresol-2: 5: 3) (Weight average molecular weight: 10,000) 8 parts by weight 2-trichloromethyl-β(2'-benzofuryl) vinyl! , 0.06 parts by weight of 3.4-oxadiazole, P-octylphenol and naphthoquinone (l.

2) Condensate with diazide-5-sulfonyl chloride (condensation rate: condensation rate of hydroxyl group 50 mol%) 0.1 part by weight Victoria Pure Blue-BOH (manufactured by Hodo Rikiya Chemical Co., Ltd.) 0.08 part by weight・Fluorine surfactant rFC-430J (manufactured by 3M) 0.1 parts by weight ・Methyl cellosolve 20 parts by weight ・Ethyl cellosolve 32 parts by weight Meanwhile, in the present invention example and the conventional example, the coating conditions were set as follows. .

Through such coating, the coating properties of the conventional example and the example of the present invention were compared, and the results were as shown in Table 2.

Table 2 On the other hand, the photosensitive lithographic printing plate thus completed was plate-made under the following exposure and development conditions, and as a result of printing under the following printing conditions, the plates with good coating properties showed that at the beginning of printing, , glossy and voluminous printed matter with good ink adhesion was obtained.

Exposure conditions: Document exposure machine consisting of two flat areas of film originals and 40% halftone dots Niidorfin 2000 Exposure conditions:
8. Omw/aj, 90 seconds Development conditions: Automatic processor
: PSQ-910 (manufactured by Konica KK) developer
: 6 times diluted solution of 5DR-1 (manufactured by Konica KM) Development conditions: 27°C, 20” Printing conditions: Printing machine: Heidel GTO ink
: Toyo Ink paper : Coated paper Blanket : Kinyosha Printing speed: 7,000 sheets/hour In addition, "register marks" were drawn on the photosensitive planographic printing plate with a ballpoint pen of an automatic registration mark drawing machine, and as a result of comparing the visual visibility, The position of the well-positioned version could be clearly seen.

〔Effect of the invention〕

As described above, according to the present invention, coating properties are significantly improved.

[Brief explanation of the drawing]

Fig. 1 is a schematic diagram of an example of the device of the present invention, Fig. 2 is a perspective view of an example of the structure of an extrusion nozzle, Fig. 3 is a schematic diagram of a conventional coating method, and Fig. 4 is a schematic diagram of an example of the device of the present invention.
The figure is a schematic diagram for explaining changes in the amount of photosensitive liquid picked up due to changes in the liquid level. l... Bat, 2... Applicator roll, 3...
・Backup roll, 4...Metaling roll, 6
... Doctor blade, 7... Photosensitive liquid tank, 8.
...Pump, 9...Filter, 20...Extrusion nozzle, 21A, 21B-...Nozzle hand, 22...Slit, 23...Pocket Figure 2 Procedural amendment (voluntary) Indication of incident 1988 Patent M ff13208521, Name of invention Relationship with the case of a person who corrects a coating device for photosensitive liquid for manufacturing photosensitive printing plates Patent applicant

Claims (1)

[Claims] (1) Apply a primary film thickness of the photosensitive solution on the support that is greater than the final film thickness,
In a coating device in which the photosensitive liquid is applied by transfer coating with an applicator roll facing the support of the printing plate, and then the applied photosensitive liquid is scraped off with an opposing metering roll; Equipped with an extrusion nozzle that performs extrusion while extruding from the nozzle,
A photosensitive liquid coating device for producing a photosensitive printing plate, characterized in that the blade for scraping off the photosensitive liquid adhering to the metering roll is a plastic blade.