JPH0423239Y2 - - Google Patents

Description

[Detailed explanation of the idea]

(Industrial Application Field) The present invention relates to a printing plate that enables printing without using water using an offset printing machine. (Prior art and its problems) So-called offset printing has the advantages of uniform ink concentration on printed matter, less thickening of characters etc. during the process of ink transfer from printing plate to printed matter, and excellent printing quality. Because of its advantages, it has been used for various printing purposes since ancient times. In recent years, offset printing has come to be widely used in the so-called form printing field. By the way, in offset printing, so-called "dampening water" is used to prevent ink from adhering to non-images on the planographic plate.
The disadvantage of offset printing is that a large amount of paper is lost or wasted paper until the steady printing state is reached due to this adjustment, and offset printing is suitable for relatively large-lot printing. However, with the slowdown in economic growth, orders for things such as form printing tend to become smaller lots, and the ratio of wasted paper to what is printed in a steady state, that is, products, increases relatively, leading to an increase in product costs. This is one of the causes. By the way, the planographic plate used in an offset printing machine (in this invention, a printing device that is set or adjusted to be suitable for offset printing is referred to as an offset printing machine) has a thickness of 0.24 mm. All I could do was print. In order to reduce the above-mentioned paper waste in the case of small-lot demand, so-called dry offset printing using a thick conventional zinc letterpress plate may be considered, at the expense of some print quality, but (The modified printing device is no longer suitable for offset printing; it does not correspond to an offset printing press in the present invention). Naturally, remodeling requires a great deal of effort and expense. In order to use a device that has been modified for dry offset printing again for normal offset printing, it is necessary to modify it for offset printing again. In other words, it has been virtually impossible to use an offset printing machine for both offset printing and dry offset printing. Ultimately, in order to meet various printing demands,
This necessitated the installation of another printing device in addition to the offset printing press, which caused problems in actual use. (Means for Solving the Problems) The present invention solves the above-mentioned problems and consists of a photosensitive resin cured layer and its support, and the photosensitive resin cured layer has a thickness of 0.10 mm to 0.18 mm. , the total thickness is 0.2mm to 0.3mm, and the support is aluminum, aluminum alloy, synthetic resin film,
Alternatively, the printing plate for an offset printing machine is characterized in that it is made of metal laminated with a plastic film. The cured photosensitive resin layer of the present invention is prepared by curing a photosensitive resin fixed to the following support by image exposure and removing the unexposed areas. The photosensitive resin has, for example, (1) a prepolymer or binder, (2) an ethylenically unsaturated compound, and (3) a photopolymerization initiator as its main components, and can be used in either liquid or solid form. be. The thickness of the photosensitive resin layer, that is, the relief height is preferably 0.10 mm to 0.18 mm; if it is smaller than this, stains will occur in non-image areas during printing. On the other hand, if it is larger than this, there will be a tendency for resolution and printing durability to decrease. The support used in this invention can be aluminum alloy, metal laminated with plastic such as polyester or polyethylene, synthetic resin film, etc. From the viewpoint of minimizing the resulting dimensional changes in the plate, aluminum or metal laminated with a synthetic resin film is suitable, and aluminum is particularly preferred. In terms of ease of handling, aluminum and its alloys are most suitable because they are light and have little risk of being cut by the cutting surface of the plate. It is also preferable to interpose an adhesive layer between the photosensitive resin cured layer and the support in order to more firmly adhere the photosensitive resin cured layer to the support. An adhesive suitable for both is selected, but urethane-based and epoxy-based adhesives are generally suitable for a wide range of applications. The thickness of the adhesive layer is about 2μ to 20μ. The overall thickness of the printing plate is preferably between 0.2 mm and 0.3 mm; if it is larger than this, it cannot be mounted on an offset printing machine. On the other hand, if it is too small, the strength will be insufficient and extra adjustment will be required. (Example) Next, an example of the present invention will be described with reference to the drawings. In FIG. 1, the imaged photosensitive resin cured layer 1 is fixed to the support. Second
In the figure, the adhesive layer 3 is interposed between the cured photosensitive resin layer 1 and the support 2 to firmly adhere them together. The method for fixing the photosensitive resin layer on the support is carried out as follows depending on the properties of the photosensitive resin. In the case of liquid photosensitive resin, there are two methods: a method of molding using a doctor knife on a support set on a flat surface, a method of laminating using a roll etc. from the top of the photosensitive resin fed onto a flat plate,
Examples include a method in which a support is set between two plates sandwiched at a constant distance via a spacer, and a liquid photosensitive resin is injected. Since the thickness of the liquid photosensitive resin to be obtained is small, it is difficult to achieve precision using the injection method, and roll molding or doctor molding are suitable for obtaining a laminate with high precision. Furthermore, the viscosity of the liquid photosensitive resin during such molding affects the thickness accuracy of the resulting laminate and the inclusion of air bubbles. In order to obtain a laminate with high precision and no air bubbles, the temperature of the liquid photosensitive resin must be 30~30℃ at 20℃.
A viscosity of 600p is desired, preferably
It is desired to have a viscosity in the range of 50 to 300p. The method of laminating a solid photosensitive resin on a support is a method of dissolving it in a solvent and then coating it.
Examples include a method of roll laminating after extrusion molding, a press method, and an injection molding method. Among these methods, in the case of coating from a solvent, it is not possible to coat thickly, and it is necessary to repeat the coating many times. Image exposure is performed by irradiating ultraviolet rays through a negative film, but at this time, if the photosensitive resin is in a liquid or sticky solid state,
It is preferable to interpose a thin film made of polypropylene, polyester, polyamide, etc. between the negative film and the photosensitive resin in order to prevent staining of the negative film. The light source used for exposure is an ultraviolet fluorescent lamp,
High pressure mercury lamp. Examples include a xenon lamp and sunlight, but anything that emits ultraviolet light may be used. After the image exposure, the desired printing plate can be obtained by removing uncured portions, drying and re-exposure as necessary. Next, an example of plate making will be explained. Fumaric acid / Adipic acid / Isophthalic acid / Diethylene glycol / Propylene glycol = 14 /
28/16/33/8 (weight ratio) is dehydrated and condensed to obtain acid value.
30 prepolymers were obtained. This prepolymer 100
Hydroxyethyl methacrylate in parts by weight
10, diacetone acrylamide 10, tetraethylene glycol dimethacrylate 30, diethylene glycol dimethacrylate 10, and benzoin isobutyl ether 4,2.6-di-t-butyl-p-cresol 0.05 were added and mixed to obtain a liquid photosensitive resin. Using plates made of various materials coated with urethane adhesive on one side as supports, image exposure (40 seconds using a 2KW high-pressure mercury lamp) was carried out using an APR AL type plate making device (manufactured by Asahi Kasei Industries) from the photosensitive resin. ), washing out the unexposed areas (spraying with 1% aqueous sodium borate solution at 40°C), drying, and re-exposure to obtain printing plates for dry offset having the structure shown in the table below.

[Table] When these printing plates were directly installed in an offset printing machine for form printing and offset printing was performed without using dampening water, good printed matter was obtained. ``Compared to wet offset printing using dampening water, there is no difference in the dimensions of the printed material, and the paper loss at the beginning of printing is 1/1/2 of the wet offset printing.
The effect was as low as about 5, and the effect was remarkable. (Effects of the Invention) As described above, the printing plate of the present invention not only makes it possible to print good-quality printed matter and significantly reduce paper waste at the start of printing, but also allows it to be installed directly in an offset printing machine. As a result, various printing demands can be met with an offset printing machine, and there is no need to install additional printing machines or require a great deal of time and effort to change plates, dramatically improving work efficiency. I was able to improve. Furthermore, since the relief height is small, the outer circumferential length does not increase when the plate is wrapped around the plate cylinder. From this point of view, there is no need to correct the image distance to a shorter value when producing a printing plate, and therefore no extra effort or equipment is required, so there is a great advantage in plate making.

[Brief explanation of the drawing]

FIG. 1 is a sectional view of one embodiment of the present invention, and FIG. 2 is a sectional view of another embodiment.

Claims (1)

[Scope of utility model registration request] It consists of a photosensitive resin cured layer and its support, the thickness of the photosensitive resin layer is 0.10 to 0.18 mm, the total thickness is 0.2 mm to 0.3 mm, and the support is made of aluminum, aluminum alloy, synthetic resin. A printing plate for an offset printing machine, characterized in that it is made of a film or metal laminated with a plastic film.