JPH07266733A - Photosensitive resin letterpress and printing method - Google Patents

Abstract

PURPOSE:To provide a photosensitive resin letterpress capable of increasing the transfer amt. of ink in letterpress spot ink printing, capable of stably continuing printing work over a long time and capable of performing printing excellent in printing effect. CONSTITUTION:A photosensitive resin letterpress is formed by further providing dot uneven parts 2 with the number of screen lines of 400-900/in and a depth of 7-30mum to the surface of a letterpress solid part. In a printing method, the desensitizing printing of pressure-sensitive copy paper is performed using the photosensitive resin letterpress to perform desensitizing treatment.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a photosensitive resin relief printing plate, and more particularly to a photosensitive resin relief printing plate capable of performing stable printing operation while increasing the ink transfer amount. And
The present invention relates to a printing method capable of obtaining particularly excellent effects when used for desensitizing printing of pressure-sensitive copying paper.

[0002]

2. Description of the Related Art The most popular type of photosensitive resin plate is an ultraviolet curable resin plate having different resin materials and hardness. In general, these resin plates are prepared by exposing a negative film to the surface of the resin plate and then exposing it to ultraviolet rays, removing the negative film, washing the plate surface with alcohol or water, and washing out the unexposed portion to carry out plate making.

[0003] A printing method of a form printing machine in which this photosensitive resin plate is attached to a plate cylinder for printing is generally letterpress printing determined by the shape of the plate. This method is a method in which ink is applied to a portion where the printing portion is higher than the other portions of the plate in a convex shape, and the ink is transferred to the printing medium.
The printing machine is composed of a plate cylinder having a relief plate, an inking device for supplying ink to the plate cylinder, and an impression cylinder.

The relief printing is often used for spot printing by transferring ink to a portion called a solid portion in a specific range, in addition to printing characters and lines. This spot printing is partial full-surface printing, and spot printing is also applied to special printing such as partial coloring and transfer ink.

The entire surface printing of the solid portion is also called printing coating, and it is necessary to uniformly and completely cover the surface of the material to be printed, unlike general coloring ink for characters and drawing lines.
Therefore, it is required to print with a larger amount of ink than general printing. However, letterpress printing is a basic printing technique in which printing is performed by balancing the ink transfer amount between the application roller of the ink supply device of the printing press and the surface of the relief printing plate, and between the printing plate and the surface of the printing medium. For this reason, it is generally difficult to uniformly and completely cover the surface of the printing medium while increasing the ink transfer amount in letterpress printing.

[0006] As an example of spot printing which is the entire surface printing of the solid portion, there is a printing method of desensitizing the pressure-sensitive copy paper by printing the desensitizing ink of the pressure-sensitive copy paper. For example, when using a pressure-sensitive copying paper utilizing a color reaction of an electron-donating color developing agent and an electron-donating developer as a form, a part of a copy form page which does not require copying is required. . In order to obtain a portion that does not require copying, it is a common practice to perform spot printing with a desensitizing ink on the surface of the pressure sensitive copying paper coated with the color developer.

In the desensitizing ink, substances such as amines, diamines and quaternary ammonium salts which suppress the activity of activated clay and acidic resins and lose the coloration reactivity with leuco dyes are reduced. Contains sensitizer. Desensitizing printing inks are oil-based or water-based inks obtained by mixing these desensitizing agents with ink media such as oils, alcohols, waxes, and resins.

Desensitizing printing is generally performed by a form printing machine for printing pressure-sensitive copying paper and processing forms, and the printing plate used at that time is generally a photosensitive resin plate although a rubber plate is also used. Unlike a rubber plate, a photosensitive resin plate can be made using a single negative film when there are many parts to be printed on one sheet, so the work of attaching the plate to the plate cylinder can be performed accurately and quickly. .

As the photosensitive resin plate, there are various UV-curable resin plates having different resin materials, hardness, etc. After the negative film is superposed on the surface of these resin plates and exposed to ultraviolet rays, the negative film is removed. The plate surface is washed with alcohol or water to wash out the unexposed area to perform plate making.

The printing method of a form printing machine, in which the photosensitive resin plate is attached to the plate cylinder for printing, is generally letterpress printing determined by the shape of the plate. This method is a method in which ink is applied to a portion where the printing portion is higher than the other portions of the plate in a convex shape, and the ink is transferred to the printing medium.
The printing machine is composed of a plate cylinder having a relief plate, an inking device for supplying ink to the plate cylinder, and an impression cylinder.

[0011]

In the conventional spot entire surface printing of the relief solid portion as described above, it is necessary to increase the ink transfer amount in order to reliably obtain the printing effect. Therefore, if it is attempted to increase the amount of ink transfer in the current spot printing ink, the ink transfer from the inking roller to the resin relief plate or the ink transfer from the resin relief plate to the substrate becomes poor, and the ink transfer surface becomes uneven. At the same time, if a large amount of ink is supplied by the ink supply device of the printing machine, ink accumulates on the plate bottom and ink transfer occurs even to parts other than the plate surface, making it impossible to continue stable printing work for a long time. An object of the present invention is to provide a photosensitive resin relief printing plate capable of stable printing for a long time even if the ink transfer amount of the spot entire surface printing of a relief printing solid portion is increased, and a printing method for performing efficient printing. I will provide a.

[0012]

The present invention provides a photosensitive resin letterpress used for letterpress printing, in which a solid dot portion of the letterpress further has a screen dot number of 400 to 900 lines / inch and a depth of 7 to 30 μm. It is a photosensitive resin relief printing plate characterized in that it is formed by making unevenness.

Further, a photosensitive resin relief printing plate is formed by further forming halftone dot reliefs having a screen ruling of 400 to 900 lines / inch and a depth of 7 to 30 μm on the surface of the relief printing solid portion of the photosensitive resin relief printing plate. It is a printing method for performing desensitization processing on pressure-sensitive copy paper using the same.

[0014]

As the photosensitive resin plate used in the present invention, there are, for example, Trelief (Toray), APR (Asahi Kasei), Printite (Toyobo), Tevista (Teijin), NAPP (Nippon Paint), Nyloprint (BASF), etc. The surfaces of these resin plates are uniformly smooth.

In the present invention, in the plate making process of these photosensitive resin plates, convex plate making for spot printing of the solid part is performed, and at the same time, the unevenness of halftone dots is further formed on the surface of the solid plate of the letterpress plate in the plate making process. This plate-making method can be obtained by a method of using a screen halftone film negative as referred to in photolithography as a negative film for exposing convex portions.

The photosensitive resin relief printing plate for spot printing obtained by this method will be described in more detail with reference to the drawings. FIG. 1 is a sectional explanatory view of a photosensitive resin relief plate of the present invention. The resin portion of the photosensitive resin plate is provided with a relief printing solid portion 1 for spot printing, and a portion 2 having halftone dots formed on the surface of the relief printing solid portion.

FIG. 2 is an example illustrating a negative film used for the photosensitive resin relief printing plate of the present invention. The negative film has a portion 4 other than the relief solid portion and a portion 5 on the surface of the solid portion to further form unevenness of halftone dots.

FIG. 3 is an explanatory view of a process for making the photosensitive resin relief plate of the present invention. In this plate making, the negative film 6 of the halftone screen is superposed and adhered on the surface of the photosensitive resin plate, and the resin is cured by irradiating and exposing the film with ultraviolet rays having a wavelength of 300 to 400 nm, and then the film is removed to remove alcohol or alcohol. Wash with water and dry. Since the high density portion of the negative film does not allow passage of ultraviolet rays, this portion of the photosensitive resin plate is not cured, and the non-cured portion is dissolved and removed by subsequent washing, so that the photosensitive resin relief plate of the present invention shown in FIG. it can.

FIG. 4 is an explanatory diagram of spot printing in a letterpress printing unit of a form printing machine using the photosensitive resin letterpress of the present invention. The spot ink 9 is transferred from the inking roller 7 onto the photosensitive resin relief printing plate of the present invention attached to the plate cylinder 8, and the ink 10 and the paper 11 and the impression cylinder 12 are formed on the paper to be printed, for example, paper. Printing pressure is applied when passing through the space.

In desensitizing printing on pressure-sensitive copying paper as an example of printing in form printing using the photosensitive resin relief printing plate of the present invention, the desensitizing ink amount is as large as 2.5 g / m ² (solid content) or more. However, the uniformity of the ink surface can be obtained and the printing operation can be stably performed for a long time. Since the surface of the convex portion of the photosensitive resin relief printing plate has unevenness of halftone dots,
A large amount of ink can be transferred from the inking roller to the plate surface and is uniform, and a large amount of transfer to the pressure-sensitive copying paper is also uniform, so that a good desensitizing effect can be obtained.

That is, when the ink is transferred from the inking roller to the convex solid portion, it also enters the halftone dot concave portion of the depression. When the ink in the concave portion is transferred to the paper surface, it is attracted and transferred to the paper surface together with the ink in the convex solid portion. Therefore, a large amount of ink can be printed on the paper surface, and at the same time, the ink surface is less likely to be non-uniform and stable printing can be performed for a long time.

In the plate making of the photosensitive resin relief plate of the present invention, it is important that the halftone dot screen is 400 to 900 lines / inch, and the plate depth of the halftone dot convex and concave portions is 7 to 30 μm. At this time, the negative film has a dot percentage of 10 to 90.
It is used by appropriately selecting from among%.

If the halftone dot screen frequency is less than 400 lines / inch, when the desensitizing ink is transferred from the inking roller to the convex solid portion, the depth of the depression of the halftone dot concave portion of the convex solid portion is too deep. The ink is not transferred to the deepest part, and the ink printed on the paper surface becomes uneven. On the other hand, if the halftone dot screen ruling exceeds 900 lines / inch, the effect cannot be obtained because unevenness can be formed only as in the original solid part.

If the dot percentage is less than 10%, unevenness is likely to occur during washing out of the plate. On the other hand, halftone dot% is 90%
If it exceeds, the halftone dot concave portion can be formed only shallowly and the concave portion becomes small, so that the effect cannot be obtained.

In the case of the desensitizing printing process on pressure-sensitive copying paper, the desensitizing ink transfer amount is printed in the range of about 0.5 to 6.0 g / m ² (solid content). Resin letterpress is 2.
This effect is particularly exhibited when printing is performed with a large ink transfer amount of 5 to 6.0 g / m ² .

[0026]

EXAMPLES Examples and comparative examples of the present invention will be described below, but the present invention is not limited to these examples.

Example 1 Photosensitive resin plate (trade name, TRELIEF WF95SS-II,
On the surface of Toray), superimpose a negative film for producing a photosensitive resin plate on a negative film with a screen line number of 440 lines / inch and a flat screen of 20% so as to obtain a substantially square convex portion of 120 mm × 110 mm. , Flat type exposure device ("Yaki")
Was used for 14 minutes for exposure, and Fuji Tray Washer FTW-300 was used for drying under conditions of 55 ° C. for 10 minutes, followed by post-exposure to make a photosensitive resin relief plate.

With a form printing machine (trade name, MUF-18, Miyakoshi) equipped with a relief printing unit, the ink transfer amount is adjusted to 7 on the ink supply setting scale of the ink supply device of the foam printing machine, and pressure sensitive copying paper is used. Medium paper (product name, KS
Desensitization printing was performed on copy bright N-40 medium paper, Shin-Oji Paper Co., Ltd. using desensitizing ink for pressure-sensitive copying paper (trade name, KS Copy Bright desensitizing ink, Shin-Oji Paper Co., Ltd.).

Table 1 summarizes the depth of the halftone dot depressions and depressions of the plate-making photosensitive resin relief plate, the value of the ink supply amount setting scale, the desensitizing ink amount on the paper surface, the state of printing workability, and the desensitizing effect. Indicated.

Example 2 In Example 1, the screen frequency was 440 lines / inch,
A photosensitive resin relief plate was made in the same manner as in Example 1 except that a negative film having a flat mesh of 80% was used, and desensitizing printing was performed in the same manner as in Example 1.

Example 3 In Example 1, the screen frequency was 600 lines / inch,
Plate making and printing were carried out in the same manner as in Example 1 except that a negative film having a 20% flat screen was used.

Example 4 In Example 1, the screen ruling is 600 lines / inch,
The plate making and printing were performed in the same manner as in Example 1 except that a negative film having a flat mesh of 80% was used.

Example 5 In Example 1, the screen ruling is 900 lines / inch,
The same procedure as in Example 1 was carried out except that a negative film having a flat screen of 20% was used.

Example 6 The same as Example 5 except that the ink transfer amount was adjusted to 11 in the ink supply setting scale of the ink supply device of the foam printing machine.

Example 7 In Example 1, the screen ruling is 900 lines / inch,
The same procedure as in Example 1 was carried out except that a negative film having a flat mesh of 50% was used.

Comparative Example 1 A photosensitive resin relief printing plate was prepared in the same manner as in Example 1 except that a negative film having only a solid portion without a screen screen was used. Desensitization printing was performed.

Comparative Example 2 Comparative Example 1 was the same as Comparative Example 1 except that the ink transfer amount was adjusted to 11 on the ink supply setting scale of the ink supply device of the foam printing machine.

Comparative Example 3 In Example 1, the screen ruling was 150 lines / inch,
The same procedure as in Example 1 was carried out except that a negative film having a flat screen of 20% was used.

Comparative Example 4 The procedure of Example 1 was repeated, except that a negative film having a screen ruling of 90 lines / inch and a flat screen 80% was used.

The results of Examples and Comparative Examples were evaluated as follows and shown in Table 1. [Measurement of Depth of Plated Halftone Recesses] A stylus-type smoothness measuring device, Mitutoyo Surface Tester 201 manufactured by Mitoyo Seisakusho Co., Ltd., a stylus tip radius of 5 μm, a measurement pressure of 4 mN, and a driving speed of 0. Measured under standard conditions of 5 mm / s.

[Ink Supply Amount Setting Scale of Letterpress Printing Unit of Form Printing Machine] The setting scale 7 is a standard condition, and the setting scale 11 is a large amount of ink supply.

[Ink Amount of Desensitizing Ink Printed on Pressure Sensitive Copy Paper] It was measured by an absolute dry weight method.

[Printing Workability of Form Printing Machine] When desensitizing ink accumulated on the plate bottom causes ink transfer to a portion other than the plate surface, it is defined as ×, and stable long-term printing can be performed. Was marked as ○.

[Desensitizing Effect] The surface not subjected to the desensitized printing is superposed on the surface of the desensitized printing portion, and writing is performed with a ballpoint pen to which a writing pressure of 300 g is applied. When the color is confirmed, it is △,
The case where no color development was confirmed was marked with ◯.

[0045]

[Table 1]

[0046]

EFFECTS OF THE INVENTION Using the photosensitive resin relief printing plates obtained in the examples of the present invention, a desensitizing ink was printed on the CF surface of pressure-sensitive copying paper to carry out desensitization. When the amount of ink is the same as that of letterpress, the ink is uniform and a good desensitizing effect can be obtained. Furthermore, the amount of ink can be increased evenly, and stable printing work can be performed for a long period of time. Was obtained.

[Brief description of drawings]

FIG. 1 is a cross-sectional explanatory view of a photosensitive resin relief plate of the present invention.

FIG. 2 is an explanatory diagram of a negative film used for the photosensitive resin relief printing plate of the present invention.

FIG. 3 is an explanatory view of a process for making a photosensitive resin relief plate of the present invention.

FIG. 4 is an explanatory diagram of spot printing in a letterpress printing unit of a form printing machine using the photosensitive resin letterpress of the present invention.

[Explanation of symbols]

1: Letterpress solid part for printing 2: Halftone dot unevenness formed on the surface of letterpress solid part 3: Base layer of photosensitive resin letterpress 4: Part other than letterpress solid part 5: Letterpress solid part Portion that further forms unevenness of halftone dots on surface 6: Negative film 7: Ink application roller of letterpress printing unit 8: Plate cylinder of letterpress printing unit 9: Ink transferred onto photosensitive resin letterpress 10: Printed material Ink transferred onto the surface 11: Substrate 12: Impressor of letterpress printing unit

Claims (2)

[Claims] 1. A photosensitive resin letterpress used for letterpress printing, further comprising a screen ruling 4 on the surface of the letterpress solid part.
A photosensitive resin relief printing plate, which is formed by making halftone dot projections and depressions having a depth of 7 to 30 μm and a depth of 0 to 900 lines / inch. 2. A photosensitive resin relief printing plate formed by further making a halftone dot relief having a screen ruling of 400 to 900 lines / inch and a depth of 7 to 30 μm on the surface of the relief printing solid portion of the photosensitive resin relief printing plate. A printing method in which pressure-sensitive copying paper is desensitized.