JPH02165151A - Device applying photosensitive liquid to photosensitive printing plate - Google Patents

Abstract

PURPOSE:To control a film thickness by a metaling roll and to surely prevent a bubble fault by using an extruding nozzle for extruding a photosensitive liquid from a slit running along a lateral direction as a first photosensitive liquid applying means. CONSTITUTION:An extruding nozzle 20 joins together a pair of nozzle heads 21A, 21B running along he lateral direction of a supporting body B, and also, secures a narrow slit 22 on the application side. Subsequently, the slit 22 is allowed to communicate with a pocket 23, the inflow hole 24 of a photosensitive liquid L is formed against the pocket 23, and end plates 25A, 25B are abutted on both ends of the heads 21A, 21B. When in this extruding nozzle 20, the photosensitive liquid L from a tank 7 is fed forcedly through a filter by a pump 8, the photosensitive liquid L flows out of the slit 22, while extending over the whole width of the pocket 23. The photosensitive liquid L allowed to flow out is applied directly onto a supporting body B. In such a manner, uneven thickness and a bubble fault, etc., 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 it with active light such as ultraviolet rays through a negative image, and polymerizing or oxidizing the exposed areas. is crosslinked and made insoluble in the developer, and the non-irradiated areas are eluted into the developer, and each area is divided into an image area that repels water and receives oil-based ink, and an image area that repels water and repels oil-based ink. This can be obtained by making it a non-image area.

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 a printed version.

In any case, in producing this type of printing plate, a photosensitive solution containing the photosensitive composition is deposited on a support, usually an aluminum plate, which has been pretreated by electropolishing, anodizing, etc. in a grain chamber. Obtained by applying.

Usually, the reverse roll coating method shown in FIG. 3 is mainly used for applying the photosensitive liquid.

That is, the photosensitive liquid is picked up by the applicator roll 2 partially immersed in the photosensitive liquid in the vat 1 and transferred onto the surface of the support 0 which is conveyed by the backup roll 3 facing the applicator roll 2. After coating, the excess photosensitive liquid I7 is wiped off using a metering roll 4, and the photosensitive liquid is returned to the vat 1 through a pan 5.

6 is made of metal, even a bronze doctor --- gray.
This is to scrape off the photosensitive liquid X that has not yet dripped and adhered to the metering roll 4 onto the pan 5. Also,
For this application, mainly determine the gap between the applicator roll 2 and the support I3 and the rotational speed (speed) of the applicator roll 3 relative to the conveyance speed of the support B,
The primary film thickness on the support B is made thicker than the desired final film W (liquid film thickness), and then the desired final film thickness is obtained by applying the metering roll 4 to the coating liquid while setting the position. ing. Therefore, with respect to the igneous thickness of the photosensitive liquid applied by the applicator roll 2, the metering roll 4 acts as a film thickness control means for obtaining the final film thickness.

(Problems to be Solved by the Invention) In the conventional coating method described in t2 and 2, since the vat L is intermittently replenished with the photosensitive liquid, fluctuations in the level of the photosensitive liquid may occur. Therefore, the constant film thickness varies depending on whether the liquid level is high or low. Especially when the liquid level is high, an excessive amount of coating may occur, causing the primary film to flow onto the support B. However, even if the film thickness is subsequently controlled by the metering roll 4, the film thickness is
This causes uneven thickness.

Incidentally, the amount of shock-up of the photosensitive liquid by the applicator roll, and therefore the film thickness hw of the same roll, is usually given by equation (11).

(η: viscosity, U: roll peripheral speed, P: density of photosensitive liquid, α
: the angle between the liquid level and the tangent to the roll) Therefore, if the above α is different, if there is a change in the liquid level, - the igneous thickness will change.

On the other hand, in this type of photosensitive liquid, a surfactant, especially a fluorine-based surfactant, is often added as a coating property improver. As the applicator roll 2 rotates, the photosensitive liquid tends to fluidize and foam. This liquid is picked up by the applicator roll 2 together with the photosensitive liquid and
i, resulting in a coating failure.

Therefore, the main object of the present invention is to provide a coating device that can prevent thickness unevenness, bubble failure, and the like.

[Means to solve the problem]

The problem described in J-1 is to apply a photosensitive solution to a thickness greater than the final film thickness on a support.
In a coating device that coats and then scrapes off the coated photosensitive liquid with an opposing metering roll to form a final layer 11; as the first photosensitive liquid coating means, a sliver along the width direction 7)
This problem can be solved by using an extrusion nozzle that extrudes the photosensitive liquid from the liquid.

[For production]

According to the invention, applying the photosensitive liquid to the support directly by means of an extrusion nozzle not only prevents fluctuations in the igneous thickness as long as the photosensitive liquid is fed at a constant feed rate. Since the above-mentioned causes of bubble generation are completely eliminated, bubble failures can be reliably prevented.

In addition, compared to the case where an extrusion nozzle is used and the photosensitive liquid is transferred once through an applicator roll, even if air gets mixed into the photosensitive liquid and there is a risk of pinhole failure, the air The only beads that may accumulate are those formed by the metering rolls, so failures caused by bubbles (air) are reduced. However, when passing through an applicator roll, there is a risk that air bubbles mixed into the photosensitive liquid may stay in the bead formed by the applicator roll and the support, resulting in the formation of a streaky primary film. be done.

[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 directly supplies and coats the photosensitive liquid onto the support B at a constant supply rate over time.

As an example of the structure of the extrusion nozzle 20, as shown in FIG.
At the same time, a narrow slit 22 is secured on the application side, and this slit 22 is communicated with the pocket 23, and an inflow hole 24 for the photosensitive liquid is formed in the pocket 23. 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 discharged photosensitive liquid is applied directly onto the support B.

Therefore, the pump 8 pushes out the photosensitive liquid to the nozzle 20.
As long as the supply rate is constant, the igneous thickness will remain constant.

Here, the filter 9 has the function of trapping bubbles, if any, as well as dust in the photosensitive liquid. eLo is a new photosensitive liquid for replenishment.

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. , the effects of the present invention become more pronounced.

The amount of the surfactant added to the photosensitive liquid is preferably 0.1 to 5 parts by weight. A specific example of the activator is rF manufactured by 3M Company.
C-430J (fluorosurfactant), Dainippon Ink Chemical Co., Ltd. “Mega Fupuk F-171°F-173,F
-815, F-142DJ, Asahi Glass “Surflon S”
-112, 3-113, S-121, S-131, S-
145j, manufactured by Shinshuyo Kasei Co., Ltd. “F-TOP EF-101,
102,121゜122J, "Span 65" (sorbitan triacetate), "Emulgen 404" (polyoxyethylene oleyl ether), manufactured by Kao Atlas Co., Ltd.
“There are Emulgen 905J (polyoxyethyl nonylphenol ether), etc.

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

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 plate with a thickness of 0.24 m, it was electrolytically polished with an aqueous hydrochloric acid solution, anodized in an aqueous sulfuric acid solution that had been desmutted with caustic soda, and then subjected to a hot water sealing treatment to produce aluminum for lithographic printing plates. Got the board.

Next, the following photosensitive liquids were coated and dried on this aluminum plate 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) diazido-5-sulfonyl chloride (condensation rate: hydroxyl group condensation rate 33 mol%) 2 parts by weight mixed cresol (phenol:
m-cresol; p-cresol = 2:5:3) (weight average molecular weight: 10000) 8
Part by weight: 1 methyl-β(2'-benzofuryl)vinyl 1,3,4-oxadiazole to 2-tricloyl 0.0
6 parts by weight p-octylphenol and naphthoquinone (1,2)-
Condensation product with diazide-5-sulfonyl chloride (condensation rate: condensation rate of hydroxyl group 50 mol%) 0, 1 part by weight Victoria Via Blue BOH (manufactured by Fukadogaya Chemical Co., Ltd.)
0808 Heavy-duty part/Fluorine surfactant rFC-430 (manufactured by 3M) O01 Heavy-duty part/Methyl cellosolve 20 parts by weight/Methyl cellosolve 32 parts by weight On the other hand, in the present invention example and the conventional example, the coating conditions were as follows. I set it like this.

Table 1 The coating properties of the conventional example and the example of the present invention were compared by such application, and the results are as shown in Table 2.

Table 2, Figure 2 [Effects of the Invention] As described above, according to the present invention, the 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 the change in the amount of photosensitive liquid pick amplifier as the liquid level changes. 1...bat, 3...bank up roll, 4...
・Metaling roll, 6...Doctor blade, 7・
...Photosensitive liquid tank, 8...Pump, 9...Filter, 2゜...Extrusion nozzle, 21A, 21B...Nozzle head, 22...Slit, 23...Boken]・
. Figure 1. Procedure Nei 1 Tingzheng Shu (spontaneous) l. Display of the case 1986 Patent Application No. 320851 2゜Name of the invention Photosensitive liquid coating for photosensitive printing plates! Relationship with the case of the person making the amendment

Claims (1)

[Claims] (1) In a coating device that applies a photosensitive liquid to a thickness equal to or greater than the final film thickness on a support, and then scrapes off the coated photosensitive liquid with an opposing metering roll to obtain the final film thickness; as the first photosensitive liquid coating means; A photosensitive liquid coating device for a photosensitive printing plate, characterized by using an extrusion nozzle that pushes out a photosensitive liquid from a slit along the width direction.