JPH0610947U - Lithographic printing plate developing device - Google Patents

Abstract

(57) [Summary] [Purpose] Rapid processing is possible, maintenance is excellent, development can be performed with a small amount of developing solution, the amount of waste solution is small, repeatability of position accuracy is good, and uniform printed images can be obtained stably. Provided is a development device for a lithographic printing plate. A developing solution supply unit having a developing solution supply section on the upper side and a lower end having a slit-like opening, and a supporting plate of the unit, the supporting plate having means for positioning the unit, A developing device for a lithographic printing plate, wherein the unit and the supporting plate are detachable.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a photosensitive lithographic printing plate developing apparatus, and more particularly to a lithographic printing plate developing apparatus utilizing a silver salt diffusion transfer method.

[0002]

[Prior art]

 A lithographic printing plate consists of an oleophilic image part that accepts oily ink and an oleophobic non-image part that does not receive ink.The non-image part is generally composed of a hydrophilic part that accepts water. ing. In ordinary lithographic printing, both water and ink are supplied to the plate surface, and the image area selectively receives the colored ink, and the non-image area selectively receives the water, and the ink on the image surface is absorbed, for example, on paper. Printing is performed by transferring it to the printing medium.

A lithographic printing plate using a silver complex salt diffusion transfer method (DTR method), particularly a lithographic printing plate having a physical development nucleus layer on a silver halide emulsion layer is described in, for example, US Pat. No. 3,728,114. No. 4, No. 4,134,769, No. 4,160,670, No. 4,336,321, No. 4,501,811, No. 4,510,228, No. No. 4,621,041 and the like, the exposed silver halide crystal undergoes chemical development by DTR development to become black silver and forms a hydrophilic non-image area. The exposed silver halide crystals become a silver salt complex by the silver salt complexing agent in the developer and diffuse to the physical development nucleus layer on the surface, and the presence of nuclei causes physical development to cause ink-accepting physical development. An image area mainly composed of silver is formed.

In the plate making method in which such a lithographic printing plate is realized, an automatic plate making camera having a developing tank and a neutralizing tank is used. However, the plate-making process by this plate-making camera is not sufficient in terms of rapid processing, and it is also troublesome to maintain. Furthermore, from the viewpoint of environmental problems, the amount of waste liquid is small or not, and it is faster and more practical. There is a strong demand for the development of a maintenance-free plate-making processing system. Furthermore, the development method in which the lithographic printing plate is immersed in the developing tank is caused by the decrease in pH and the development speed due to continuous processing, the generation of silver sludge and the drag pattern due to the movement of the developing solution, and the flow of the silver complex. There were many drawbacks such as image deletion.

JP-A-48-76603, JP-A-57-115549 and the like describe a method for plate-making by applying and supplying a developing solution in an amount necessary for developing a lithographic printing plate onto the plate surface. . Further, JP-A-62-238564 and the like propose a method of supplying a developing solution onto the PS plate through a slit formed by two plate materials as a so-called PS plate development processing method. . However, in all of these methods, in order to achieve uniform development with only the amount of developer practically required for development, it is difficult with the conventional coating and feeding method, and a considerable amount of excess developer is required. Was to be.

Further, in the above-mentioned slit developing method, it is necessary to wash the developing portion or replace the deteriorated developing portion, but the developing portion is always installed in a fixed positional relationship with the planographic printing plate. Otherwise, there is a problem that stable development cannot be performed.

[0007]

[Problems to be solved by the device]

 The object of the present invention is a silver complex salt that does not have the drawbacks of plate making by the immersion development method, can be processed rapidly, has excellent maintenance, has a small amount of developing waste liquid, and can form a uniform printed image stably with reproducibility. An object of the present invention is to provide an image forming apparatus suitable for developing a lithographic printing plate using a diffusion transfer method.

[0008]

[Means for Solving the Problems]

 The above-mentioned object of the present invention comprises a developer supply unit having a developer supply unit on the upper side and a slit-shaped opening at the lower end, and a supporting plate of the unit, and the supporting plate is a means for positioning the unit. It is achieved by a developing device for a lithographic printing plate, characterized in that the unit and the supporting plate are detachable.

Hereinafter, the developing device of the present invention will be described in more detail with reference to the drawings, but the present invention is not limited to the embodiments of these drawings. FIG. 1 is a side view showing an example of a preferred image forming apparatus of the present invention, and FIG. 2 is a perspective view thereof. FIG. 3 is a perspective view in which the developer supply unit 1 and the support plate 9 are viewed separately. The developer supply unit 1 forms a slit-shaped opening 6 with a sheet 2a and a sheet 2b (which is expressed as a sheet for convenience, but it does not necessarily mean two sheets), and a metering pump 3 is provided at an upper position. It has a basic structure in which a developer supply unit 5 for supplying a developer from the developer tank 4 between the sheet 2a and the sheet 2b is provided, and the unit 1 is detachably attached and fixed to a support plate 9. To be done.

In a preferred embodiment of the present invention, the sheet 2a and the sheet 2b are the developer supply unit 1 in which both side ends and the upper end are closed and only the lower end 6 is opened. An amount of developer required for substantially developing M is supplied by the constant amount pump 3, stably spreads uniformly in the width direction, and flows out from the slit-shaped opening 6. While the planographic printing plate M is being conveyed, the developing solution sent from the metering pump 3 flows out from the slit-shaped opening 6, but when the planographic printing plate M is not conveyed, the metering pump 3 does not operate and the developing process is performed. The liquid does not flow out while being confined in the developer supply unit 1. The shape in which only the lower end 6 of the developer supply unit 1 is opened may be integrally molded, or the sheet may be folded so that both ends are joined with a tape, an adhesive, or the like, or the fold is the upper end. You may create it.

As the material of the sheet constituting the developing solution supply unit 1, for example, a plastic film such as polyester, polypropylene, polyvinyl chloride, polyethylene, polystyrene or the like, a metal such as stainless steel, a sheet of rubber or the like may be used. However, it is necessary to select a material that does not cause corrosion due to the pH of the developer and various components. The thickness depends on the material, but is preferably about 100 to 500 microns. Further, the lengths of the lower end openings 6 of the sheets 2a and 2b may be the same or one of the sheets may be long.

The developer supply unit 1 is provided with the developer supply unit 5 at an upper position thereof, but it is not always necessary to mount the developer supply unit 5 on the sheet 2b as shown in FIG. 1, and the upper ends of the sheets 2a and 2b are not necessarily attached. You may make it provide in a part and supply a developing solution. The length from the developer supply part 5 to the slit-shaped opening 6 is preferably as short as possible because the developer is stagnant in the unit when the planographic printing plate M is not conveyed, but when it is too short, Since it is difficult for the developer to spread uniformly in the width direction, the optimum length is determined according to the distance between the sheet 2a and the sheet 2b, the width of the lithographic printing plate M, and the like. Preferably, a length of about 30 mm to 300 mm is suitable. However, this length varies depending on the viscosity of the developing solution, liquidity such as surface tension, the supply rate of the developing solution, and the like, and can be changed as necessary.

In the developing device of the present invention, it is preferable that the sheet 2 a and the sheet 2 b are in close contact with each other from the developer supply section 5 to the slit-shaped opening section 6. The adhesiveness between the sheet 2a and the sheet 2b is such that the supplied developing solution spreads in the width direction of the sheet due to a capillary phenomenon, whereby the width direction is uniform and the planographic printing plate is developed. This makes it easier to control the amount of developing solution required. The optimum distance between the sheet 2a and the sheet 2b varies depending on the viscosity of the developer, surface tension, and other liquid properties, the supply rate of the developer, and the like, as long as the supplied developer spreads in the width direction. Good, and generally, it is preferably 0.5 mm or less.

Since the amount of the developing solution flowing out from the slit-shaped opening 6 of the developing solution supply unit 1 is small, even if the temperature of the developing solution in the developing solution tank 4 is adjusted, it may vary depending on the season or the working environment. However, there is a problem that the temperature of the developing solution in the unit is greatly affected and the plate making state of the lithographic printing plate M is not stable. However, when the supporting plate 9 is provided with a heating means, the amount of the developing solution is small, The temperature can be sufficiently controlled even with the developing solution in the state in which it is possible to perform plate production with good reproducibility and stability.

In FIG. 3, the support plate 9 is preferably a metal plate such as stainless steel, and a pin bar 10 having at least two pins is provided above the support plate 9. On the other hand, the sheet 2a and the sheet 2b of the developing solution supply unit 1 are provided with pin holes 11 at positions corresponding to the pins of the support plate 9. The pin holes 11 of the developer supply unit 1 are fitted into the pins of the support plate 9 and fixed with screws or the like. By doing so, even if the developer supply unit 1 is replaced, the same positional accuracy with respect to the lithographic printing plate M can always be ensured.

The above-described developing device of the present invention may have, for example, openings on both side ends of the sheet 2a and the sheet 2b. However, in order to prevent the developer from leaking from the opening, as described above, The supply unit 1 is preferably open only at the lower end 6. The width of the developer supply unit 1 may be shorter than the width of the lithographic printing plate M processed by the developing device of the present invention, but is usually designed to be longer (FIG. 2). However, also in this case, there is an advantage that the developing solution hardly leaks from the lower end opening portion 6 which exceeds the width of the planographic printing plate M.

The developing solution supply unit 1 of the present invention may have only one developing solution supply section 5, but a plurality of planographic printing plates M may be provided if necessary.

As shown in the figure, the developer supply unit 1 preferably has a curved surface shape with a gentle bulge on the lower side. The inclination angle of the developer supply unit 1 is preferably about 30 ° to 70 ° as a straight line connecting the upper end and the lower end.

The supply amount of the developing solution applied to the lithographic printing plate M varies depending on the type of the lithographic printing plate and the type of the developing solution, but is generally in the range of 10 to 200 ml, preferably 20 to 100 ml per 1 m ^2. Is. The developing time varies depending on the type of the lithographic printing plate, the conveying speed, the composition of the developing solution, the developing temperature and the like, but it is generally about 3 to 30 seconds. The developing temperature is preferably in the range of 10 to 40 ° C., and the sheet 2a is heated in advance to a desired developing temperature by a heating means.

The developed planographic printing plate M is then preferably subjected to a neutralization treatment. The neutralization process may be carried out by dipping in a conventional neutralization tank, but like the developing system of the present invention, it is called reducing the amount of waste liquid by applying and supplying the necessary amount of neutralizing liquid to the plate surface. It is also good from the aspect.

The lithographic printing plate utilizing the silver complex salt diffusion transfer method processed by the developing device of the present invention has an antihalation undercoat layer, a silver halide emulsion layer and a physical development nucleus layer on a support. And their details are well known as described in many patent specifications and the like. As the support for the lithographic printing plate, paper, or a synthetic or semi-synthetic polymer film, a metal plate of aluminum, iron, etc., which can withstand lithographic printing, can be used.

The developing solution used in the developing apparatus of the present invention includes alkaline substances such as sodium hydroxide, potassium hydroxide, lithium hydroxide, and sodium triphosphate, sulfites as a preservative, and halogenated compounds. Silver solvents such as thiosulfates, thiocyanates, cyclic imides, 2-mercaptobenzoic acid, amines, etc., antifoggants such as potassium bromide, compounds described in JP-A-47-26201, and developers. For example, hydroquinones, catechol, 1-phenyl-3-pyrazolidone and the like, development modifiers such as polyoxyalkylene compounds and onium compounds can be included. Furthermore, compounds such as those described in U.S. Pat. No. 3,776,728, which improve ink transfer of the surface silver layer, can be used in the developing solution.

As described in JP-A-48-76603, the developing solution used in the present invention contains a viscous agent such as carboxymethyl cellulose or hydroxyethyl cellulose to have a viscosity of 0.5. It may be in the range of -100 cp, preferably 1-20 cp.

[0024]

【Example】

 The present invention will be described below with reference to embodiments, but the present invention is not limited to this.

Example A developing device as shown in FIG. 1 was prepared. The developing solution supply unit 1 uses a polyester film having a thickness of 200 μm, and the length from the developing solution supply section 5 to the lower end opening 6 is 120 mm and the width is 500 mm, and the upper end and both ends are hermetically sealed, and only the lower end opening 6 is formed. Is open. A pin hole is provided above the developer supply unit 5 so as to correspond to the pin of the pin bar. As shown in FIG. 3, a rubber heater was attached to the surface of the support plate (metal plate) 9 to which the pin bar 10 was attached, the pin holes of the developer supply unit 1 were fitted into the pins of this support plate 9 and fixed with screws. The inclination angle is about 45 °. An apparatus for supplying the neutralizing solution was also made in the same manner as the above developing apparatus.

As the planographic printing plate M, a silver master (trade name) manufactured by Mitsubishi Paper Mills Ltd. was used. The developer and neutralizer used had the following composition. The temperature of the heater was set so that the temperature of the developing solution when it came out from the lower end opening 6 was 25 ° C.

<Transfer Developer> 700 ml of water 20 g of potassium hydroxide 50 g of anhydrous sodium sulfite 50 g 2-mercaptobenzoic acid 1.5 g 2-methylaminoethanol 15 g Water is added to make 1 liter.

<Neutralization liquid> Water 600 ml Citric acid 10 g Sodium citrate 35 g Colloidal silica (20% liquid) 5 ml Ethylene glycol 5 ml Water is added to make 1 liter.

The lithographic printing plate M is conveyed at a speed of 30 mm / sec by the conveying rollers 7 a and 7 b, and when the leading end of the lithographic printing plate M reaches the lower end opening 6, the developing solution flows out from the lower end opening 6. It has become. The amount of developer supplied to the unit is 1 m of the planographic printing plate. ² The metering pump 3 controls the volume to be 35 ml. When the rear end of the planographic printing plate M reaches the lower end opening 6, the metering pump 3 is stopped. The developer remaining in the unit hardly spilled. The squeeze rollers 8a and 8b squeeze a small amount of the excess developing solution, and the subsequent processing in the neutralizing device is performed. Neutralizing solution is 1m of planographic printing plate²A metering pump is used to control the volume to 30 ml.

The planographic printing plate M prepared by the above operation was mounted on an offset printing machine, the following desensitizing liquid was applied all over the plate surface, and printing was performed using the following dampening liquid.

<Desensitizing Solution> Water 600 ml Isopropyl alcohol 400 ml Ethylene glycol 50 g 3-Mercapto-4-acetamido-5-n-heptyl-1,2,4-triazole 1 g

<Moisturizing Liquid> o-phosphoric acid 10 g nickel nitrate 5 g sodium nitrite 5 g ethylene glycol 100 g colloidal silica (20% liquid) 28 g Water is added to make 2 liters.

As the printing machine, AB DIC 350CD (trademark of an offset printing machine manufactured by AB Dick) was used. The lithographic printing plate M was capable of extremely uniform development over the entire plate surface and showed sufficiently high printing durability without uneven development.

The test was repeated as described above by replacing with another developer supply unit, and the same result was obtained.

[0035]

[Effect of device]

 According to the developing device of the present invention, rapid processing is possible, maintenance is easy, and by using an extremely small amount of developer, the amount of waste liquid is small, uneven development does not occur, and high printing durability is achieved. A lithographic printing plate can be obtained. Further, since the developer supply unit 1 can be easily replaced and the mounting position accuracy is good, stable and stable plate making is possible.

[Brief description of drawings]

FIG. 1 is a side view of a developing device of the present invention.

FIG. 2 is a perspective view of the developing device of the present invention.

FIG. 3 is a perspective view of a developer supply unit and a support plate.

[Explanation of symbols]

 1 Developer Supply Unit 2a, 2b Sheet 3 Metering Pump 4 Developer Tank 5 Developer Supply Section 6 Slit-shaped Opening 7a, 7b Conveying Rollers 8a, 8b Squeezing Roller 9 Support Plate 10 Pin Bar 11 Pin Hole M Planographic Printing Plate

Claims (2)

[Scope of utility model registration request] 1. A developer supply unit having a developer supply unit above and a slit-shaped lower end, and a support plate for the unit, the support plate having means for positioning the unit. The developing device for a lithographic printing plate, wherein the unit and the support plate are detachable. 2. The developing device according to claim 1, which is a developing solution supply unit in which the developing solution supply section and the slit-shaped opening section are substantially in close contact with each other.