JP2007062314A - Printing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a printing method capable of combining a comparatively small number of colors to display many colors and also expressing a feeling of irregularity in only color inks. <P>SOLUTION: (a) In this printed matter 1, a plurality of ink layers 3a, 3b, 3c, 3d, 3e, ... are successively formed on the surface of a printing material 2 by screen printing to express many display colors 4a, 4b, 4c, 4d, 4e, ... by a combination of laminated states. (b) In the case of a conventional printed matter 11, many colors of inks are blended and are formed on the surface of the printing material 2 as respective ink layers 13a, 13b, 13c, 13d, 13e, resulting in an increase in the number of inks, finally with the increase in the number of plates and the number of necessary processes. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a printing method capable of multicolor printing.

  Conventionally, screen printing using a screen plate has been performed in addition to so-called three-plate printing of a relief plate, a planographic plate and an intaglio plate. In three-plate printing, ink is placed on a printing line and transferred to the printing medium, whereas in screen printing, ink is transferred to the printing medium through holes in the printing line. Therefore, the types of ink that can be used increase (for example, see Non-Patent Document 1).

  In screen printing, a thick ink layer can be formed as compared with other printing techniques. Paintings created using oil paints can also be reproduced with faithful colors. The original image is divided into different color areas, ink for reproducing colors is prepared for each area, and screen printing is performed using as many plates as the number of colors. Since the ink layers of the respective colors are formed to be sufficiently thick, the prepared color can be reliably displayed. Further, if a transparent and thick layer is formed on the surface, it is possible to express unevenness.

  However, in the case of screen printing, gradations that change in gradation from dark to light, from light to dark, and from one color to another have many plate restrictions, compared to other printing methods. Are said to be difficult.

Edited by Japan Screen Printing Technology Association, “New Screen Printing Handbook”, January 31, 1988, p. 1-6, p. 365-368

  Color display is performed by the difference in hue, saturation, and brightness. In paintings and the like, the color boundary is not always clear by the operation of a brush or the like, and a gradation region in which the gradation changes with a natural feeling is also formed. If you try to smoothly reproduce gradation changes in gradation, many inks with slightly different colors are required, so the conventional printing technique does not change the color, but changes the dot diameter or the distribution of the dot pattern The gradation of gradation is expressed by the change of density. However, for the same color ink, the gradation is not smooth enough if the gradation is simply expressed by changing the dot diameter at a single density. When many colors are mixed and used properly, the number of necessary plates increases and the number of printing processes also increases.

  In addition, in order to form a transparent layer on the surface in order to give an uneven feeling by screen printing, a screen plate for forming a transparent layer is also required. If only one transparent layer is formed, the three-dimensional unevenness is not sufficient. Therefore, when a plurality of layers are formed, a screen plate and a process are further required.

  An object of the present invention is to provide a printing method that can display a large number of colors by combining a relatively small number of inks, and that can express a concavo-convex feeling only with the color inks.

  According to the present invention, a plurality of colors exceeding a plurality of colors can be obtained by selectively combining a plurality of layers of ink layers while sequentially printing transparent inks of a plurality of colors including a primary color system to form an ink layer. It is a printing method characterized by enabling display.

  According to the present invention, since the transparent ink is printed, each ink layer can be formed thick. The formed ink layer is transparent including the primary color system, and is affected by the color of the ink layer on the base, so that many colors can be expressed by combining up to a plurality of layers. Since colors are displayed with a combination of transparent inks and a printing pattern, a relatively small number of inks can be combined to display a large number of colors, and unevenness can be expressed with only color inks. .

Further, the present invention provides the combination of the stacked states for displaying the color, the combination of up to the plurality of ink layers for each color that can be displayed, with the printing order of the transparent ink being determined in advance. , The printing pattern of each ink layer is standardized in advance,
According to the standardization, each color is displayed while selectively forming each transparent ink layer by printing.

  According to the present invention, a combination of a plurality of transparent inks and a print pattern for forming an ink layer are standardized in advance with respect to colors to be displayed, so that color reproduction can be performed stably. In the process of sequentially printing the layer of transparent ink on the substrate, the combination is selected according to the color to be displayed. Therefore, a lot of ink layers are laminated on the color portion using many transparent inks. It can express deep colors and richness. Since the lamination thickness differs depending on the color, it is possible to express a difference in unevenness as well as a difference in color.

In the present invention, the primary color system includes a plurality of transparent inks having different densities,
A smooth gradation is reproduced by stacking a plurality of transparent inks of the same color system and having different densities so that the high density side is on the upper side.

  According to the present invention, by superimposing transparent ink layers having the same color and different densities, a natural change can be expressed with a smooth gradation without a sudden change in density. Since stacking is performed so that the high density side is on the top, dark colors can be expressed in a profound manner.

  According to the present invention, since the ink layer formed by printing is transparent, it is influenced by the color of the underlying ink layer, and is compared with a selective combination of a plurality of ink layers including the primary color system. Even when a small number of colors of ink are combined, many colors can be displayed, and the unevenness can be expressed only with the color ink.

  Further, according to the present invention, the combination of transparent inks and the dot pattern to be combined can be standardized in advance for the colors to be displayed, and the colors can be reproduced stably. A lot of ink layers are laminated on a color portion using a lot of transparent ink, so that a deep color tone and a rich feeling can be expressed, and a difference in unevenness can also be expressed.

  Further, according to the present invention, it is possible to express a natural change with a smooth gradation by overlapping layers of transparent inks having the same color and different densities.

  FIG. 1 shows a comparison between a printed matter formed in an embodiment of the present invention and a conventional printed matter in a schematic cross-sectional configuration. In the printed matter 1 of the present invention shown in FIG. 1 (a), a plurality of ink layers 3a, 3b, 3c, 3d, 3e,... A combination of the stacked states of a plurality of ink layers 3a, 3b, 3c, 3d, 3e,..., More display colors 4a, 4b, 4c, than the number of ink layers 3a, 3b, 3c, 3d, 3e,. 4d, 4e,... Can be expressed. Each of the ink layers 3a, 3b, 3c, 3d, 3e,... Is formed by screen printing a transparent ink. The transparent ink includes resins that are components for forming an ink film, colorants, auxiliaries, and the like. Resin is a synthetic resin such as thermoplastic, thermosetting, or UV curable, colorless and transparent, or close to this, blended with inorganic pigments, organic pigments, extenders, etc., concentration and transparency Is adjusted.

  FIG. 1B shows a conventional printed matter 11. In the conventional printed matter 11, a plurality of ink layers 13 a, 13 b, 13 c, 13 d, 13 e,... Are arranged on the surface of the printing medium 2 for each color area to display a color image. The ink layers 13a, 13b, 13c, 13d, 13e,... Include four basic colors of three primary colors of C (cyan), M (magenta), and Y (yellow) and K (black). A color different from each primary color is displayed by combining a plurality of primary color inks as a dot pattern. In ink jet printing or the like, a plurality of colors having different densities may be used as primary color inks. In screen printing and offset printing, colors are not displayed by a combination of primary color dot patterns, but ink can be prepared according to the color to be displayed in advance, and the ink layer can be directly formed with the prepared color. . However, the number of inks increases, and the number of plates and the number of necessary processes increase.

  FIG. 2 shows a combination of the stacked states of the ink layers 23a, 23b, 23c; 33a, 33b, 33c, and more colors 34a, 34b, 34c, more than the number of the ink layers 23a, 23b, 23c; 33a, 33b, 33c. A principle capable of displaying 34d, 34e, 34f, and 34g will be described. As shown in FIG. 2A, a plurality of ink layers 23 a, 23 b, 23 c having different dot densities for the first color 23 are formed on the surface of the printing medium 2, and the dot density for the first color 33 is A plurality of different ink layers 33a, 33b, and 33c are formed. For example, it is assumed that the ink layers 23a and 33a are solid, the ink layers 23b and 33b are large-diameter dots, and the ink layers 23c and 33c are small-diameter dots. The second color ink layer 33a is formed on the first color ink layers 23a and 23b. The ink layer 34b for the second color is formed on the ink layers 23b and 23c for the first color. The second color ink layer 33 c is formed on the first color ink layer 23 c and the surface of the printing medium 2. The first color ink layer 23a has a portion that is not covered by the second color ink layer 33a, and this portion appears as a color 34a. The second color ink layer 33a has a portion of the first color ink layer 23a and a portion of the first color ink layer 23b as the base, and appears as different colors 34b and 34c. The second color ink layer 33b also appears as different colors 34d and 34e, reflecting the difference between the underlying first color ink layers 23b and 23c. The ink layer 33c of the second color appears as different colors 34f and 34g, reflecting the difference in the ground between the ink layer 12c of the first color and the surface of the printing medium 2.

  FIG. 2B shows display colors realized by a combination of the two color inks 23 and 33 shown in FIG. “A”, “b”, and “c” correspond to the reference numerals of the ink layers 23a, 33a; 23b, 33b; For example, the second color 33a can be directly formed on the surface of the first color 23c or the printing medium 2 as well as the first colors 23a and 23b as shown in FIG. Therefore, the combination of FIG. 2 (b) does not show all possible, but shows only a partial range corresponding to FIG. 2 (a). As shown in FIG. 2A, when each of the ink layers 23a, 23b, and 23c; 33a, 33b, and 33c is divided into three print patterns and printed, including the case of not printing, the upper second color Each of the 33 ink layers 33 a, 33 b, and 33 c can be combined with four types as the lower first color 23. In some cases, only the ink layers 23a, 23b, and 23c of the lower first color 23 are provided. In some cases, the surface color of the printing medium 2 does not form any ink layer.

  Accordingly, there are 4 × 4 = 16 colors that can be displayed in all possible combinations. For example, when two C (cyan) colors, two M (magenta) colors, two Y (yellow) colors and one K (black) color are used, a total of seven colors are used. Similarly to FIG. 2A, when three types of print patterns are used for each color, 4 × 4 × 4 × 4 × 4 × 4 × 4 = 16384, and even if all combinations cannot be realized. About 16000 colors can be displayed. For example, the CMY primary colors may have different densities. It is also possible to increase the number of colors that can be realized by increasing the number of primary colors to three or more.

  If the number of colors as described above is realized by the conventional printing technique as shown in FIG. 1B, even if gradation is realized to some extent by a combination of dot patterns and halftone dots, it is 100 or more. Requires many editions and processes. In the printing technique of FIG. 1A according to the present invention, when the CMY primary colors are two colors, a plate of 2 + 2 + 2 + 1 = 7 colors and a screen printing process may be executed.

  In FIG. 2A, when the order in which the first color 23 and the second color 33 are stacked is changed, the display color also changes, and more colors can be displayed. That is, since transparent ink is screen-printed, each ink layer 23a, 23b, 23c; 33a, 33b, 33c can be formed thick. Since the formed ink layers 23a, 23b, and 23c; 33a, 33b, and 33c are transparent, they are influenced by the color of the underlying ink layer, and many colors 34a, 34b, 34c, and 34d are combined in a plurality of layers. , 34e, 34f, and 34g can be expressed.

  However, in order to change the stacking order of the ink layers in the same printed matter 1, it is necessary to use the same color ink a plurality of times and change the plate each time. Therefore, a combination of a plurality of transparent inks for a displayed color and a dot pattern for combining the colors are standardized in advance including the printing order of the plurality of transparent inks. In this standardization, in the same color system color, the light color side is printed first and the dark color side is printed later according to the difference in light and shade. Colors to be used and their printing order are preset and standardized, including differences in primary color systems. Each color is displayed while selectively forming each transparent ink layer by screen printing according to standardization.

  That is, a combination of a plurality of transparent inks and a dot pattern for combining colors are standardized in advance with respect to colors to be displayed, so that color reproduction can be performed stably. In the process of sequentially screen-printing the ink layers 23a, 23b, 23c; 33a, 33b, 33c of the transparent ink on the substrate 2 according to the display colors 34a, 34b, 34c, 34d, 34e, 34f, 34g, Since the combination is selected, many ink layers 23a, 23b, 23c; 33a, 33b, 33c are laminated on the color portion using many transparent inks, and a deep color tone and a rich feeling can be expressed. Since the lamination thickness differs depending on the color, it is possible to express a difference in unevenness as well as a difference in color.

  FIG. 3 shows a schematic procedure for producing the printed material 1 as shown in FIG. In step s1, an image of a document to be printed is input. An original image can be input by reading from the original image with a color scanner. Moreover, image data can also be created directly as computer graphics. In step s2, color analysis is performed to determine what color portion the input image can be divided into. In the color analysis, it is determined which of a plurality of display colors 34a, 34b, 34c, 34d, 34e, 34f, and 34g as shown in FIG. When it is determined which of the display colors 34a, 34b, 34c, 34d, 34e, 34f, 34g of the area belongs, as shown in FIG. 2B, the display colors 34a, 34b, 34c, 34d, 34e. , 34f, and 34g, and the dot patterns are determined. In the next step s3, plate making for producing a screen printing plate is performed corresponding to each of the inks 23 and 33. In the screen printing plate of each color, gradation is displayed with a standardized dot pattern. In the next step s4, the inks 23 and 33 are sequentially used in accordance with the standardization, and multicolor screen printing is performed using the screen printing plate manufactured for each ink. After screen printing with one color, after the ink is dried and an ink layer is formed, screen printing with the next color is performed.

  When the display color is obtained by screen printing a plurality of times as in the present embodiment, if the position of the screen printing plate with respect to the printing medium 2 is shifted between screen printing processes, the display color also changes. For this reason, when screen printing is performed on the object 2 by the screen printing apparatus, it is necessary to prevent the object from being displaced. Further, every time one ink is screen-printed on the surface of the object 2, the ink must be sufficiently dried to form the ink layers 23a, 23b, 23c; 33a, 33b, 33c. If the lower ink layers 23a, 23b, and 23c are insufficiently dried, color mixing occurs between the upper ink layers 33a, 33b, and 33c, and the target display colors 34a, 34b, 34c, 34d, 34e, There is a possibility that the color may be displayed differently from 34f and 34g. However, if the printing medium 2 or the ink layers 23a, 23b, 23c; 33a, 33b, 33c expands or contracts during drying, a positional shift occurs during the screen printing of the next ink. It is necessary to do enough.

  FIG. 4 shows an example in which the manufacturing unit price of the printed material 1 according to the present invention is compared in FIG. 4A while changing the number of prints between a conventional silk-screen printing and multi-color silk screen printing and inkjet printing. The solid line indicates the printed matter 1 of the present invention, the alternate long and short dash line indicates the multicolor silk print as shown in FIG. 1B, and the broken line indicates the ink jet printing. Conventional multicolor silk prints require many plates and processes, so the unit price is high. Inkjet printing does not require a plate, so the initial unit price is low, and is almost constant regardless of the number of printed sheets. However, it is necessary to use an ink that can form a jet well, and the cost of the ink is relatively high. In the printed matter 1 according to the present invention, as the number of printed sheets increases, the cost burden on the plate decreases and the unit price decreases. In this example, when the number of printed sheets increases to about 100 or more, the unit price decreases as compared with inkjet printing.

  FIG. 4B shows the production period required according to the number of printed sheets 1 in comparison with a conventional multi-colored silk-screen print with a one-dot chain line and an inkjet print with a broken line. In the printed matter 1 and the conventional multicolor silk print, the initial production period is longer than the ink-jet printing that does not require a plate by the amount necessary for the plate, and if the number of printed sheets is small, it is longer than the ink-jet printing. Cost. However, since printing is performed using a plate, printing on the printed matter 1 of the present invention is completed in a short time. Therefore, if the number of printed sheets is large, the printing speed is faster than that of inkjet printing, and the production period is shortened. In ink jet printing, printing is performed while the head moves and scans the surface of the printing medium. Therefore, when the number of printed sheets increases, the production period also increases in proportion to the number of sheets. In the printed matter 1 of the present invention, the screen printing and drying are repeated a plurality of times. However, when the number of printed sheets increases, printing and drying of one color are continuously performed. At the stage of moving to the next color printing, the drying of the ink layer of the previously printed one has been completed, and the next color printing can be performed immediately. Since the drying is also completed, the influence can be ignored even if the drying time is required.

  FIG. 5 shows a comparison of characteristic evaluations obtained by each printing technique of multicolor screen printing, silk printing by conventional multicolor silk screen printing, and inkjet printing of the printed matter 1 of the present invention. In the reproducibility of the original picture, the fineness of the expression, the color gradation, and the gradation expression, the present invention and the ink jet are excellent, and the silk print is good. In terms of unevenness in the thickness of the ink, the present invention in which the ink layers are laminated is excellent, and a silk print that can obtain a thick ink layer as screen printing is good. Inkjet cannot increase the thickness of the ink. In the sense of deepness of color, the present invention that can obtain a thick ink layer as a screen print and the silk print are excellent, and it is difficult to obtain a richness by inkjet. In terms of weather resistance (fading / temperature / humidity), the present invention and silk prints, which can sufficiently use light-resistant pigments, are excellent. Ink jets are difficult to use with large particle pigments that plug nozzles. The effect of temperature and humidity is excellent in the present invention and silk prints because the ink layer is formed thick and is not easily affected. In inkjet, a fine dot pattern may be affected by changes in temperature and humidity.

  As described above, in the printed matter 1 of the present invention, other printing techniques, reproducibility of an original image, fineness of expression, color gradation, gradation expression, ink thickness / concaveness, color depth / thickness, etc. Even if the characteristic level evaluations are compared, it can be seen that all items are excellent. Also, it can be seen that the physical durability of the printed surface such as weather resistance is superior to other printing techniques.

  Furthermore, in the printed matter 1, a plurality of transparent inks having different densities are prepared for each primary color system of CMY, and a plurality of transparent inks having different densities in the same color system are stacked, so that a sharp change in density is achieved with a smooth gradation. It is possible to express natural changes. Further, since the stacking is performed so that the higher density side is on the upper side, the dark color can be expressed in a profound manner.

  In addition, clear printing can be performed on the surface of the printed matter 1, or an opaque color, metal powder, metal foil, or the like can be added to a part thereof. Screen printing is also preferred because it forms a thick layer of ink, but can be applied to other printing techniques as well.

It is typical sectional drawing which compares and shows the printed matter formed in one Embodiment of this invention, and the conventional printed matter. It is typical sectional drawing and a chart which show the principle which can display more colors than the number of ink layers by the combination of the lamination | stacking state of an ink layer. It is a manufacturing process figure which shows the schematic process of manufacturing the printed matter 1 as shown to Fig.1 (a). It is a graph which shows the example which compares the manufacturing unit price and production period of the printed matter 1 by this invention, changing the number of printed sheets between the conventional multicolor silk-screen print and inkjet printing. It is a graph which compares and shows the characteristic evaluation obtained by each printing technique of the multicolor screen printing of the printed matter 1 of this invention, the conventional silk print, and an inkjet printing.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Printed matter 2 To-be-printed body 3a, 3b, 3c, 3d, 23, 23a, 23b, 23c, 33a, 33b, 33c Ink layer 4a, 4b, 4c, 4d, 4e, 4f, 34a, 34b, 34c, 34d, 34e , 34f, 34g Display color

Claims (3)

  While a plurality of colors of transparent ink including the primary color system are sequentially printed to form an ink layer, it is possible to display more than a plurality of colors by selectively combining the layers of the ink layers up to the plurality. A printing method characterized by the above. The combination of the stacked states for displaying the colors is determined in advance in the printing order of the transparent ink, and for each color that can be displayed, a combination of the plurality of ink layers, Standardize the print pattern in advance,
The printing method according to claim 1, wherein each color is displayed while selectively forming each transparent ink layer by printing according to the standardization. In the primary color system, a plurality of transparent inks having different densities are prepared,
3. The printing method according to claim 1, wherein a smooth gradation is reproduced by stacking a plurality of transparent inks having the same color system and different densities so that the high density side is on the upper side.