KR20060125316A - Off-set printing method for spot color print - Google Patents

Abstract

An offset printing method for printing spot color is provided to secure good color development effect, to express texture and matiere by using a special ink and a special process, and to maximize the effect of the spot color by adding an additive. The offset printing method for printing spot color comprises the steps of: separating spot color printed parts of the final printed article according to the spot color; supplying a spot color manuscript film correspondent to the spot color printed parts separated according to the spot color and primary color manuscript films divided according to the primary colors; forming a primary color print plate and a spot color print plate printed with pictures by the development of the primary color manuscript film and the spot color manuscript film, according to the spot or primary color; printing the spot colors by using an offset printer equipped with the spot color print plate; and printing the primary colors by using the offset printer equipped with the primary color print plate.

Description

Offset printing method for spot color printing {OFF-SET PRINTING METHOD FOR SPOT COLOR PRINT}

1 is a diagram for explaining one printed matter.

2 to 5 are diagrams of the printed matter of FIG. 1 separated according to the four primary colors.

6 is a front view of an offset printing press for implementing the offset printing method according to the present invention.

7 is a drawing of a partly modified yellow original film for spot color printing the first and second spot color printing portions according to this embodiment.

8 is a drawing of a spot color original film from which a first spot color printing portion is separated.

9 is a drawing of a spot color original film from which a second spot color printing portion is separated.

10 is a diagram showing parameter adjustment for emphasis processing of the second spot color printing portion.

11 is a diagram showing a result of emphasizing the second spot color printing portion.

FIG. 12 is a drawing with dotted dots for some of the yellow original films of FIG. 7. FIG.

FIG. 13 is a diagram illustrating a process of brightly highlighting a spot color in the drawing of FIG. 12.

FIG. 14 is a diagram illustrating a process for strongly highlighting a spot color in the figure of FIG. 12.

<Explanation of symbols for the main parts of the drawings>

1: Offset printing machine 10: Paper feeder

20: spot color printing part 30: primary color printing part

40: medium 22: ink supply roller

24: Printing board roller 26: Rubber blanket roller

28: pressure roller

The present invention relates to offset printing, and more particularly, to an offset printing method for printing using a spot color in addition to the standard primary color.

Offset printing is a type of flatbed printing. In offset printing, printing is performed on paper indirectly, not directly on a printing plate. Specifically, offset printing uses an indirect printing method that first prints on a rubber plate or rubber blanket on a printing plate, and then transfers to paper passing through the rubber plate and tenderness. In addition to paper, offset printing can be used to print various materials such as cloth and cans in color, and it is mainly used when printing newspapers, magazines, catalogs, etc., because all colors that can be identified by eyes can be expressed almost identically. .

Offset presses generally include printing plates, official boxes and pressure cylinders. By the original film, a picture shape divided into a line portion and a non-line portion can be expressed on the printing plate, and the printing plate in which the figure is expressed is mounted on the surface of the printing plate. In the printing plate, the drawing line portion corresponding to the drawing has lipophilicity, while the non-drawing line portion has hydrophilicity. Therefore, when ink is supplied from the upper part of the printing plate, ink can be delivered only through the wire line part, and the ink of the wire line part is first transferred to the rubber box to be printed on the rubber blanket. As the paper passes between the rubber tub and the pressure vessel, the pressure vessel adheres the paper to the rubber tub, and the ink printed on the rubber tub is transferred to the paper to perform printing on color.

1 is a diagram illustrating one printed matter, and FIGS. 2 to 5 are diagrams of the printed matter of FIG. 1 separated according to four primary colors.

For reference, in order to express the color printed matter of FIG. 1, FIGS. 2 and 5 are required colors using the CMYK mode using four primary colors of cyan, magenta, yellow and black. Can be implemented.

1 to 5, three primary colors or four primary colors are used to express general colors, and various colors can be expressed by mutual overlapping or mixing of these primary colors.

Specifically, in the offset printing, the original film for each primary color is produced by the CTP (Computer To Plate) method, and the image of the original film can be developed on the aluminum plate coated with the photoresist through the baking process using these original films. . In this way, blue (C), red (M) and yellow (Y) are the basic colors, and black (K) can be added to form four colors.These colors can be overlaid and printed to produce subtle hues. have.

In general, in the original film, a dot may be expressed using dots, and the printing plate for the fourth degree primary color may adjust the density of colors while varying the density or size of the dots. In addition, the halftone of each printing plate may implement an overlapping effect between the primary colors while varying the angle of orientation or slightly changing the center position of the halftone.

Sometimes high-quality printing uses a printing press of 5 degrees or more that adds spot colors in addition to the CMYK primary colors. Special colors such as gold, silver, etc. can be expressed through spot colors, and by using separate inks, colors with high saturation or soft color can be expressed.

One object of the present invention is to provide an offset printing method that can maximize the use effect of the spot color.

Another object of the present invention is to provide an offset printing method capable of enriching color development, texture, and matier expression for colors by using spot colors.

According to a preferred embodiment of the present invention for achieving the above object of the present invention, the present invention is a method for printing a printed matter using an offset printing machine, in addition to the three primary colors or four primary colors using a specially treated portion using a spot color It is characterized by including in the printed matter. In particular, a spot color original film corresponding to the spot color printing portion is produced, and the spot color is first printed before printing the primary color using the spot color original film. By printing spot colors first, you can improve the expressive effect such as texture or matier, and you can prevent the tone-down caused by color overlap.

Specifically, the spot color printing portion to be used for spot colors in the final printed matter may be divided into one or two or more. Spot color printing parts may be distinguished according to the spot color used, and spot color printing parts using the same spot color may be separated or may be attached to each other. A spot color original film corresponding to a spot color printing portion separated for each spot color may be provided, and a primary color original film obtained by dividing the remaining area into three primary colors or four primary colors corresponding to the spot color printing portions may be provided. In this case, the primary color original film may have a region overlapping with or separate from the spot color original film, and may include a portion overlapping and partially separating. For example, it is possible to expect the effect on the color development of the primary color by using the superposition and to obtain effects such as complementary color contrast. In addition, by clearly separating the spot color region and other regions, it is possible to express precisely and to express a special texture. Also, by harmonizing overlap and separation, colors can be connected naturally.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings, but the present invention is not limited or limited by the embodiments.

6 is a front view of an offset printing press for implementing the offset printing method according to the present invention.

Referring to FIG. 6, the offset printer 1 includes a paper feeding unit 10, a spot color printing unit 20, a primary color printing unit 30, and a discharge unit 40. The paper sheet 10 is loaded with printing paper, and the printing paper is picked up one by one in response to the operation of the offset printer 1. The picked-up printing paper passes through the spot color printing unit 20 and the primary color printing unit sequentially, and the printing paper passes through the spot color printing unit 20, and a picture shape by spot color is printed on the paper, and goes through the primary color printing unit 30. The picture shape by the primary colors is printed. Each spot color or primary color picture can be superimposed or separated to produce a single print. The printing paper passing through the primary color printing unit 30 is transferred out of the offset printing machine 1 through the discharge unit 40, and is loaded in the loading unit 50. When a certain amount of printing paper is accumulated in the stacking unit 50, ink may be deposited on the back side of the printed matter, and thus, printed matter loaded in a predetermined amount unit may be transferred to another storage location in order to prevent ink.

In the present embodiment, the offset printer 1 includes one spot color printing unit 20 and four primary color printing units 30, and the spot color printing unit 20 is installed in front of the primary color printing unit 30 so that the printing paper is The spot color printing unit 20 is first passed. However, the spot color printing unit 20 may further increase according to the number of spot colors to be used, and the number of primary colors may also use three primary colors. That is, the number of spot color printing unit 20 and primary color printing unit 30 may be variously selected according to a user's intention, and spot color printing and primary color printing may be separately performed. In general, since the spot color printing unit 20 and the primary color printing unit 30 may vary depending on the original film and the ink used, the conversion is very easy.

Referring again to FIG. 6, the spot color printing unit 20 includes an ink supply roller 22, a printing plate roller 24, a rubber blanket roller 26, and a pressure roller 28.

Spot color ink is supplied from the top of the ink supply roller 22 and the printing plate roller 24, and can be delivered indirectly to the printing plate roller 24 through the ink supply roller 22 or directly to the printing plate roller 24. . In general, by placing several ink supply rollers 22 around the printing plate roller 24 and allowing the ink to be supplied through the ink supply roller 22, the ink may be evenly and thinly spread.

The printing plate roller 24 is equipped with an aluminum printing plate. A picture shape corresponding to a spot color is represented on the printing plate, and the picture shape of the printing plate includes a lip line having a lipophilic portion and a non-flaming line having a hydrophilicity. When oil-based ink is used, ink is applied only to the caustic line of the printing plate, and ink is not applied to the non-hydroline caustic line having hydrophilicity. That is, the first printing according to the shape of the picture may be performed on the rubber blanket roller 26 by using the repulsive force between water and oil, and indirectly transferred to the paper through the rubber blanket roller 26.

To make a printing plate, a spot color original film is brought into close contact with an aluminum plate coated with a photoresist, and then the original film and the aluminum plate are exposed to ultraviolet light together. Among them, the portion of the film blocked by the image of the film is fixed to the plate to become a caustic part, the part exposed to the light is washed with water or the like to become a non-radiation part. The printing plate thus produced has a picture shape having lipophilic or hydrophilicity, and the printing plate in which the picture shape is expressed is mounted on the surface of the printing plate roller 24.

A rubber blanket is mounted on the surface of the rubber blanket roller 26. The rubber blanket roller 26 receives the ink smoothly from the printing plate roller 24, and the ink delivered to the rubber blanket is transferred to the paper again. Rubber blankets should be replaced frequently as a medium for delivering ink, and if the blankets are uneven or have foreign objects, the printing results may be poor. In addition, the presence of the rubber blanket roller 26 allows the shape printed on the paper to be directed in the same direction as the picture shape expressed on the printing plate roller 24.

The rubber blanket roller 26 and the pressure roller 28 rotate while keeping in close contact with each other. Thus, the paper is printed while passing between the rubber blanket roller 26 and the pressure roller 28, and the pressure roller 28 presses the paper so that the ink of the rubber blanket roller 26 is permeated into the paper.

The pressure roller 28 may use a flat metal surface as it is, and the paper conveyed by the rubber blanket roller 26 and the pressure roller 28 is transferred to the next primary color printing part 30 through the delivery roller 29. Can be.

Although the spot color printing unit 20 has been described, the configuration of the spot color printing unit 20 is substantially the same as the primary color printing unit 30, and the description of the spot color printing unit 20 is also described in the primary color printing unit 30. It can be applied almost identically.

Hereinafter, the printing method according to the present invention will be described according to the work order.

First, referring to FIG. 1 again, the printed matter is displayed in color, and conventionally, as shown in FIGS. 2 to 5, after outputting a primary color original film according to CMYK, a printing plate is produced, and the produced printing plate is respectively. It can be attached to the primary color printing unit to perform color printing.

In order to use the spot color, various spot colors and parts may be selected, but in the present embodiment, the uppermost person's top is defined as the first spot color printing part 100 and the bottom of the person in the center is the second spot color. This is defined as the print portion 200.

The first spot color printing portion 100 may be expressed through an overlap of red (M) and yellow (Y) as orange. Among these, referring to FIG. 3, the first spot color printing part 100 overlaps with the same area as the yellow area 212 of FIG. 4 in the remaining area 112 except for the shadow area 114, and the two primary colors overlap. Orange color is expressed by. In the present exemplary embodiment, spot color printing may be directly performed on an orange color of a person's upper right side.

FIG. 7 is a drawing of a partly modified yellow original film for spot printing the first and second spot color printing portions according to the present embodiment, and FIG. 8 is a drawing of the spot color original film separating the first spot color printing portion.

7 and 8, the area 100a corresponding to the first spot color printing portion corresponding to the image of the right person in the yellow original film is deleted, and the first image corresponding to the image of the right person in the red original film is deleted. The remaining area of the spot color printing portion except for the shadow 114 is deleted (not shown). As shown in FIG. 8, portions corresponding to the tops are provided separately, and orange colors may be directly printed in spot colors corresponding to those provided separately.

9 is a drawing of a spot color original film from which a second spot color printing portion is separated.

7 and 9, the area 200a corresponding to the second spot color printing portion corresponding to the bottom of the center person is deleted from the yellow original film. In the second spot color printing part 200, a bright color may be expressed by using bright yellow, and yellow may be emphasized over a conventional printed matter. For this purpose, a process for highlighting a spot color can be performed through a graphic editing program or a print editing program.

The lower portion of the shadow portion 224, which is represented by yellow, has a higher density of yellow dots because of the density of halftones, and the remaining portion 222 except for the shadow portion 224 has a relatively small density of halftone dots, so that the ratio of yellowness is small. Specifically, the ratio of halftones of the remaining portion 222 may be increased to the maximum halftone size.

FIG. 10 is a diagram showing parameter adjustment for emphasis processing on the second spot color printing portion, and FIG. 11 is a diagram showing a result of highlighting the second spot color printing portion.

Referring to FIG. 10, when defining a level from 0 to 255 according to the size of the dot among the separated second spot color printing parts 200, the density of the dot is increased by adjusting the midtone from 1.00 to 0.44, and the spot color as a whole. You can do this to highlight the part.

As a result, as shown in FIG. 11, the size of the halftone in the print area separately processed corresponding to the second spot color printing part 200 is switched to the maximum size as a whole, and bright yellow may be printed in the spot color. By increasing the size of the halftone and being connected as a whole, the second spot color printing portion 200 may also obtain an effect such as engraving.

After defining the first spot color printing portion 100 and the second spot color printing portion 200, the first spot color original film corresponding to the first spot color printing portion 100 for each spot color and the second spot color printing portion 200 correspond to each other. A second spot color original film can be made. In addition, the primary color original film can be provided in which some of the primary color original films are removed or modified depending on the spot color printing portion. As shown in FIG. 7, the portion 100a corresponding to the first spot color printing area and the portion 200a corresponding to the second spot color printing area are removed from the modified yellow original film.

After producing the spot color and primary color original films, the spot color printing plate and the primary color printing plate can be produced for each spot color or primary color. As mentioned above, in order to manufacture a printing plate, a thin photosensitive liquid is coated on an aluminum plate, and a fired part and a non-fired part may be distinguished through a baking process using a film. It is possible to mount and use a printing plate in which the picture shape is expressed by the drawing line part and the non-drawing part in the printing plate roller 24.

As shown in FIG. 6, the spot color printing unit 20 and the primary color printing unit 30 are sequentially arranged around the paper feeding unit 10. The spot color is printed for each spot color using the offset printing machine 1 equipped with the spot color printing plate, and after printing the spot color, the primary color may be printed for each primary color using the offset printing machine equipped with the primary color printing plate. In the present exemplary embodiment, the spot printing unit 20 and the primary color printing unit 30 are both included in one offset press, but in some cases, the spot printing unit and the primary color printing unit may be separately provided to two or more offset presses. connect.

In general, the primary colors include four primary colors corresponding to Cyan, Magenta, Yellow, and Black, and the four primary colors are black, blue, and red. It prints in the order of (M) and yellow (Y). After the printing plate is mounted on the printing plate roller 24, the printing process is performed from spot color printing. There may be overlapping areas in the spot color original film and the primary color original film, and the primary color original films overlap with each other in the shadow portions 114, 124, and 224. The primary color can be superimposed on a spot color using the overlapping film region, and the color development which cannot be expressed by superimposition of primary colors can be obtained.

In addition to the overlapping, separate spot color areas can be used for various textures and precise expressions. To this end, the halftone dot in the overlapping area of the primary color original film may be partially or entirely removed corresponding to the second spot color printing part, and the primary color and the spot color may be separated from each other and printed on the removed part. It can solve the dissatisfaction with sharpness when printing and can solve the problem of overlapping dots.

FIG. 12 is a drawing in which half of the yellow original film of FIG. 7 is dotted, and FIG. 13 is a view illustrating a process of brightly highlighting a spot color in the drawing of FIG. 12.

12 and 13, when defining a level from 0 to 255 according to the size of the halftone, the halftone of the entire bright part may be removed by adjusting the brightest level among the halftone input levels from 255 to 105. Among the spots corresponding to the spot color in the spot color printing portion, a dot below a predetermined reference size may be removed, and the spot color may be printed using the remaining dot dots, thereby increasing the bright portion.

FIG. 14 is a diagram illustrating a process for strongly highlighting a spot color in the figure of FIG. 12.

12 and 14, when defining a level from 0 to 255 according to the size of the halftone, the halftone may be increased by adjusting the darkest level among the halftone input levels from 0 to 101. This can maximize the density or size for dots of more than a certain size. As a result, dots corresponding to spot colors can be emphasized, and can be used to further emphasize spot colors. That is, among the halftones corresponding to the spot color, a halftone having a predetermined reference size or more may be replaced with a halftone having a maximum size, and the spot color may be printed using the replaced halftone and the remaining halftone.

In addition, as shown in FIG. 10, among the spots corresponding to the spot color in the spot color printing part, a dot more than a predetermined reference size is replaced with a dot of the maximum size, and the dot less than the predetermined reference is reduced to 0% and removed. After that, the spot color may be printed using only the halftone dots substituted with the maximum size.

By using spot colors, color effects can be obtained in printed colors. In addition, the use of separate inks and processes can enrich the texture and expression of Matier, and can also express the feeling of color or texture in the artist's paintings. When printing, additives are used for spot colors to maximize the effect on spot inks.

In addition, it is possible to remove the loss of dots or contamination of the baking sheet generated during the baking process, and to prevent the ink leaving phenomenon during printing.

In addition, it is possible to express precisely and to solve the problem of clarity and light resistance.

As described above, although described with reference to the preferred embodiment of the present invention, those skilled in the art various modifications and variations of the present invention without departing from the spirit and scope of the invention described in the claims below I can understand that you can.

Claims (7)

In the offset printing method for printing the printed matter according to the shape of the image separated in correspondence with the primary color and the spot color, Separating spot printing parts corresponding to each spot color in the final print by the spot colors; Providing a spot color original film corresponding to the spot color printing portions separated by spot colors and a primary color original film separated by primary colors, respectively; Forming a spot color printing plate and a primary color printing plate printed with a picture shape by the spot color or the primary color through development using the spot color original film and the primary color original film; Printing a spot color for each spot color using an offset printer equipped with the spot color printing plate; And Printing the spot color and then printing the primary color for each primary color using an offset printer equipped with the primary color printing plate; Offset printing method using a spot color having a. The method of claim 1, The primary colors include four primary colors corresponding to Cyan, Magenta, Yellow, and Black. The four primary colors are black, blue, red, and yellow. Offset printing method using a spot color, characterized by printing in the sequence of series. The method of claim 1, In the providing of the spot color original film and the primary color original film, the spot color original film and the primary color original film corresponding to the spot color printing part include areas overlapping each other, and the spot color using the overlapping film area. The offset printing method using a spot color, characterized in that the primary color is superimposed on. The method of claim 1, In the step of providing the spot color original film and the primary color original film, partial or total removal of halftones in an overlapping area of the primary color original film corresponding to the spot color printing part is partially removed, and the primary color and The offset printing method using the spot color, characterized in that for printing the spot color separated from each other. The method of claim 1, In the spot color printing portion, among the dot dots corresponding to the spot color, a dot dot having a predetermined reference size or more is replaced with a dot dot of the maximum size, and the spot color is printed using the substituted dot dot and the remaining dot dot. Offset printing method. The method of claim 1, In the spot color printing portion, among the dots corresponding to the spot color, a dot below a predetermined reference size is replaced with a dot of the minimum size, and the spot color is printed using the substituted dot and the remaining dot. Offset printing method. The method of claim 1, Of the spots corresponding to the spot color in the spot color printing portion, a dot of more than a predetermined reference size is replaced with a dot of the maximum size, and after removing the dot of less than the predetermined reference, only the dots replaced by the maximum size are used. Offset printing method using a spot color, characterized in that for printing a spot color.

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