JP3504616B2 - Building board printing equipment - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a building plate printing device capable of coping with small-lot multi-kind production by making a plate for printing unnecessary by utilizing ink jet technique. SOLUTION: Cell parts 2a, having predetermined shapes, are arranged around the surface of circumference of a gravure roll 2 with a predetermined pitch. An ink jet mechanism 3 is provided with respective recording heads 31-34 for injecting ink of respective colors cyan, magenta, yellow and black against respective cells and a printing controller 35. One image element of an image to be printed is formed of neighboring 13 pieces of cell parts. The printing controller 35 obtains one image element having a desired color density by changing the area rate of an ink dot of four kinds of C, M, Y, K based on the color data of respective image elements of the image to be printed. The ink, supplied to respective cells 2a of the gravure roll 2, is transferred to the surface of the building plate 8 through an offset roll 5.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a building board printing apparatus, and more particularly, to printing on a building board that uses inkjet technology to eliminate the need for a printing plate and support small lot, multi-product production. Regarding the device.

[0002]

2. Description of the Related Art Techniques for printing a design pattern on a building board by using a gravure offset printing machine are known from JP-A-9-30099 and JP-A-11-20297. Japanese Unexamined Patent Publication No. 10-151722 describes a gravure printing apparatus that can use a common gravure cylinder and that does not require time-consuming gravure cylinder manufacturing or plate making for each printing. This gravure printing device is a gravure cylinder with many cells uniformly formed on the surface, an ink filling means for filling the gravure cylinder with ink, and a part of the gravure cylinder filled with ink according to the image to be printed. Ink removal means for removing ink from the cell, means for recovering the removed ink, and means for printing by pressing the printing material against the gravure cylinder after removing a part of the ink.

[0003]

The gravure offset printing method and the gravure printing method can express gradations close to photographic quality, but it is necessary to manufacture gravure plate rolls for each pattern. Furthermore, in order to reproduce a multicolor image or a full color image by this method, a plurality of color-separated gravure plate rolls are required. For example, in order to reproduce a full-color image, four types of gravure plates separated for each color of cyan, magenta, yellow, black, etc. are produced, each ink corresponding to each plate is supplied, and printed in sequence. I will go.

On the other hand, like a general inkjet printer, cyan (C), magenta (M), yellow (Y), and black (K) inks are jetted and supplied to a paper, which is an object to be printed, to obtain a full-color image. There is a printing system that realizes printing. In such a system, since it is not necessary to produce a plate at all, it is possible to change the print contents for each sheet of paper, which is very convenient.

However, since many of the building boards have irregularities in the design surface (further, variations in the thickness of the boards are added), it is tentatively attempted to apply the inkjet printing system. However, since the distance between the ink jet nozzle and the printing surface is not constant,
It becomes extremely difficult to control the desired printed pattern.

In addition, the printing area of the building board is very large (for example, 455 mm × 1818 mm) and the production speed is as high as 24 m / min. A printing system that requires 4 to 5 minutes to print a size cannot handle multicolor printing on a building board at all.

As a method of coating a building board using an ink jet method, Japanese Patent No. 3115136 (Japanese Patent Application No.
No. 331042), an ink jet coating method for a building board using an ink ejecting means of a valve opening / closing control method, and an ink ejecting means of a piezo vibration control method disclosed in JP-A-9-201564 are used. Although there is an inkjet coating method for a building board, etc., none of them can cope with the above-mentioned condition that the distance between the ink jet nozzle and the printing surface is not constant.

Further, a pattern pattern is drawn on the transfer belt by using an ink jet coating machine as disclosed in JP-A-10-128230 (in that case, the distance between the ink jet nozzle and the transfer belt is constant. ), There is also a method in which the pattern is developed on the surface of the building board by pressing the transfer belt against the design surface of the building board. However, there is a problem of running accuracy of the transfer belt (a problem of the ink supply device), a transfer There is a problem such as pattern deviation due to the fact that the belt is held between the roll and the running building board, and it is hard to say that the processing will never be stable.

On the other hand, JP-A-10-151722
The gravure printing apparatus described in the publication can commonly use the gravure cylinder for any image printing. However, it is necessary to produce a printing plate for removing ink corresponding to the image to be printed.

It takes a predetermined number of days to manufacture a gravure plate roll and a printing plate for removing ink. Also,
When changing the pattern (image) to be printed, it is necessary to change the gravure plate roll and the printing plate for removing ink. For this reason, a printing method using a plate such as a gravure plate roll or a printing plate for removing ink cannot flexibly cope with small lot multi-product production.

Therefore, there is a demand for a technique capable of performing printing with a quality close to that of gravure printing or gravure offset printing without using a physical plate. In addition, there is a demand for a technique that enables multicolor printing or full-color printing with one printing without overprinting, such as an inkjet printing system.

As a color-developing method of an ink jet printer, a dither pattern gradation method of an area gradation method is generally adopted. There is also a type in which ink dots of four colors of CMYK are overlapped and recorded (for example, refer to Japanese Patent Laid-Open No. 9-141943).

When the material to be printed is a building board to be built on the outer wall of a building, the pattern size of the building board can be viewed from a distance. However, even if the degree of dispersion of each pixel is considerably sparse, it is sufficient to identify the pattern at a distance. Therefore, there is a need for a coloring method suitable for such conditions.

The present invention has been made in order to solve such a problem, and it is possible to perform printing with a quality close to gravure printing or gravure offset printing on a building board without using a physical plate. An object is to provide a building board printing device.

[0015]

In order to solve the above-mentioned problems, a building board printing apparatus according to the present invention relates to a gravure roll which holds ink to be supplied in a plurality of cell parts and rotates, and the cell parts. An ink jet mechanism that jets and supplies ink, an offset roll that is transferred to the gravure roll and that transfers the ink held on the gravure roll and transfers it to a building board, and for one pixel of an image to be printed corresponding to the color of the pixel to be printed with assigning a plurality of cell portions adjacent Te the individual cell portion Inkuji
And a print control unit that sets the ink supplied by the printing mechanism . Thereby, one pixel is formed by a plurality of halftone dots (ink dots colored by the ink supplied to one cell portion), and the area ratio of the four types of ink dots of C, M, Y, and K is changed. By doing so, one pixel having a desired color density can be obtained.

Each of the plurality of cell portions is a square having the same size and its diagonal line is parallel to the axial direction of the gravure roll, so that the pitch of ink ejection is larger than the area of the cell portion. Can afford to.

[0017] The inkjet mechanism, in a Turkey be injected selectively to different ink to each of said cell portions can be formed colored pattern pattern for a plurality of cell portions with 1 pixel. The inkjet mechanism ejects inks of different concentrations with the same dye.
In the Turkey, it is possible to improve the color reproducibility.

[0018] The print control unit, peripheral in one stroke Motonai
By controlling so as not to supply ink to the cell portions of side portions, reduce the time if that by hue concentration adjacent pixel has Ru juxtaposed color mixture, be colored independently the hue of each pixel it can. The printing control unit 1 stroke element
By supplying the ink to more than half of the plurality of cell portions in the inside , it is possible to enhance the collocated color mixing effect.

[0019]

BEST MODE FOR CARRYING OUT THE INVENTION Preferred embodiments of the present invention will be described in detail below with reference to the accompanying drawings. Figure 1
FIG. 1 is a schematic structural diagram of a building board printing apparatus according to the present invention.
The building board printing apparatus 1 shown in FIG.
, Inkjet mechanism 3, gravure roll cleaning mechanism 4, offset roll 5, offset roll cleaning mechanism 6, backup roll 7, and rolls 2, 5, 7
And a mechanism (not shown) for rotating the.

Reference numeral 8 is a ceramic building board. The ceramic building board 8 is transported by a transport mechanism (conveyor device) (not shown) and travels between the backup roll 7 and the offset roll 5. In the present embodiment, the building board 8 is subjected to undercoating and a drying treatment after the undercoating, and an intermediate coating and a drying treatment after the middle coating, and the entire surface of the building board is a groove portion (recess) of the building board. It is colored. In addition, when the convex portion of the building board that is about to be printed is subjected to the base treatment before printing, for example, when the convex portion is printed on white, gray color, light beige, etc. The effect becomes more remarkable.

On the peripheral surface of the gravure roll 2, a large number of cells (grooves) 2a having the same shape and the same depth are arranged at uniform intervals. The inkjet mechanism 3 is a gravure roll 2.
Recording heads 31, 32, 3 arranged facing each other
3, 34 and the print control device 35.

The recording head 31 is an inkjet head for supplying cyan ink, the recording head 32 is an inkjet head for supplying magenta ink, and the recording head 33 is an inkjet head for supplying yellow ink. The recording head 34 is an inkjet head that supplies black ink. Inkjet head groups C1, M1, Y1, for supplying dark ink to the recording heads 31, 32, 33, 34, respectively.
K1 and inkjet head groups C2, M2, Y2 and K2 for supplying a light color ink are provided as a set, and a total of eight nozzle arrays are arranged facing the gravure roll 2.

Each of the recording heads 31 to 34 has a large number of nozzles on the bottom surface for ejecting ink. Ink ejection control from the individual nozzles of each of the recording heads 31 to 34 is based on a piezo element control method. The ink chambers forming each nozzle portion are connected to a common ink tank for ink supply. Each recording head 31
To 34, a large number of ink jet nozzles are integrated in order to cover a direction (short direction) that intersects the running direction of the building board 8 that is the print target.

Regarding the arrangement pitch of the nozzles, in the field of office equipment, it is 1/360 inch (about 0.07 inch).
mm) and 1/600 inch (about 0.04 mm) with higher resolution have been put to practical use, but the pattern (image) printing on a building board does not have to be that high resolution.

The recording heads 31 to 34 are installed accurately by appropriate means so that the ink ejection direction from the individual nozzles of the recording heads 31 to 34 is the direction toward the center of rotation of the gravure roll 2. It is located in. The recording heads 31 to 34 are removably positioned by appropriate means. This facilitates replacement of the recording heads 31 to 34 and cleaning of the nozzle tip.

The print control device 35, based on the rotational position of the gravure roll 2 and preset ink ejection data (pixel data of an image to be drawn), each ink jet head group C1, M1, Y1, K1, C2. M2, Y2, K
Ink ejection is controlled for each of the two individual nozzles. As a result, the color and shade of the ink supplied to the individual cells 2a of the gravure roll 2 are controlled.

On the gravure roll 2, a gravure roll cleaning mechanism 4 is arranged in front of the recording head 31 so as to face it. The gravure roll cleaning mechanism 4 includes a cleaning liquid jetting and supplying head 41 for jetting and supplying a cleaning liquid toward each cell 2a of the gravure roll 2, and the untransferred ink remaining in the cell 2a together with the cleaning liquid supplied to the cell 2a. The suction / recovery head 42 for suction / recovery, a suction blower (not shown), and a recovery tank.

The cleaning liquid jet supply head 41 has recording heads 31 to 31 for cleaning the surface of the gravure roll 2.
A cleaning nozzle array similar to that of 34 is provided. The suction / recovery head 42 is provided with a tapered suction hood having a slit-shaped opening, and the tip of the suction / recovery head 42 is recovered by a suction blower into a recovery tank.

The offset roll 5 is the gravure roll 2
Have been transferred to. The offset roll cleaning mechanism 6 includes a cleaning roll 61, a cleaning spray head 62,
It consists of a doctor roll 63 and a recovery bath 64. In order to clean the surface of the transferred offset roll 5 after the ink is transferred to the building board 8, a cleaning roll (made of sponge) 61 is rollingly contacted with the offset roll 5. Further, a cleaning spray head 62 for spraying the cleaning liquid from above is provided in the recess of the rolling contact portion between the cleaning roll 61 and the offset roll 5.

The cleaning spray head 62 is provided with a plurality of spray nozzles for supplying the cleaning liquid, and the cleaning liquid is jetted in an airless manner using a plunger pump or the like. Then, the cleaned liquid transferred to the cleaning roll 61 is recovered in a recovery bath 64 provided below by a doctor roll (made of stainless steel) 63 which is brought into contact with the cleaning roll 61.

FIG. 2A is an external perspective view of the gravure roll, and FIG. 2B is an enlarged view of the roll surface of the gravure roll. As shown in FIG. 2 (b), the minute cells 2 a formed on the roll surface have an inclination angle of 45 degrees with respect to the axial direction of the gravure roll 2, that is, the diagonal lines of the cells 2 a are arranged parallel to the axial direction. Has been done. By thus forming the cell array of 45 degrees, the halftone dot pitch can be made 1 / √2.

The cells 2a of the gravure roll 2 may be formed by an etching method or a mechanical engraving method. Generally, in gravure printing, the opening width of each cell in the gravure plate roll is set to a lower limit of 30 to 35 μm width from the viewpoint of ink transferability, and the cell depth is set to about 2 to 50 μm.

FIG. 3 is a diagram showing a specific example of the arrangement of cells and the arrangement of nozzles. 3A is a plan view of the cell, FIG.
(B) shows a sectional view of the cell. In this embodiment, the opening width of the cells 2a is 0.1 mm (100 μm), and the width of the bank portion between the cells is 0.02 mm. As a result, the cell pitch becomes 0.12 mm. Therefore, by arranging the cells at an inclination angle of 45 degrees as described above, the number of halftone dots is about 300 (= 25.4 × √2 / 0.12) / It can be about an inch. The opening width of the cell is about 1/3.
(About 33 μm), which can further increase the resolution.

In this embodiment, the depth of the cell 2a is set to 50.
μm. If 90% of the cell volume of ink is supplied so that the ink contained in the cell does not flow out of the cell, the amount of ink contained in one cell is 4
It is about 50 pL (picoliter). The cell volume is basically determined by the coloring power of the ink.

When the amount of ink ejected from one nozzle at one time is about 225 pL, two nozzles are provided for one cell having a required capacity of 450 pL, so that one ejection is required. The ink amount can be supplied.

FIG. 3C is a diagram showing the arrangement relationship of nozzles for each cell. Therefore, as shown in FIG. 3C, each ink jet head group C1, M1, Y1, K is arranged so that two nozzles face one cell 2a.
1, C2, M2, Y2 and K2 are formed.

Assuming that the line speed (conveyance speed of the building board 8) is 24 m / min (0.4 m / sec), the time required for one cell to pass immediately below one recording head is the diagonal width of the cell opening (140 μm). ) ÷ (0.4 m / sec) = 350 μsec, and the nozzle ejection frequency is 2860 times / sec. Normal,
Since the injection control of about 10,000 times / second is possible, this value is a value that can be sufficiently controlled. Then, specifically, ink is ejected by applying a pulse voltage of a set predetermined frequency to each piezoelectric element drive electrode. Ink ejection timing and the like are controlled in synchronization with the conveyance control of the building board 8.

Alternatively, one nozzle may be faced with respect to one cell, and a predetermined amount of ink may be supplied into the cell by a plurality of ink ejections. Also, the ink may be sequentially supplied to each cell by scanning the recording head.

In the present embodiment, since the volume of each cell is the same, it is not possible to express gradation by changing the amount of ink supplied to each cell. However, since the recording heads 31 to 34 are configured to be able to supply two sets of dark and light ink, the color density can be changed, and the color reproducibility is excellent.

Next, the coloring method in the present invention will be described. The present invention uses a coloring principle that is very similar to that of a commercially available inkjet printer. That is, one pixel is formed by many halftone dots. Therefore, within one pixel formation area
In (in the area where one pixel is formed ), the area ratio of each ink dot (halftone dot) of four kinds of inks of C, M and Y which are the three primary colors of the color material and pure black K Colors are mixed by changing (density) and have a predetermined density 1
A so-called area gradation method for obtaining pixels is adopted.

As a color forming method of an ink jet printer, there is a type in which ink dots of each of four colors of CMYK are superposed and recorded. However, in the present invention, since the respective inks are not superposed at all, it is used in the present invention. The color mixing method is
It can be said that this is a kind of side-by-side color mixing method of additive color mixing. Therefore, in contrast to the subtractive color mixture method in the former case of overlapping the dyes (note that the normal gravure offset printing also uses the subtractive color mixture method), in the present invention, only the additive color mixture is used. Based on the calculation.

By the way, in general, a commercially available ink jet printer adopts a dither pattern gradation method of an area gradation method. However, in the present invention, the material to be printed is a building board to be constructed on the outer wall of the building. In consideration of the special use state that the pattern is viewed from a distance, the ink dot diameter to be printed may be considerably larger than that of a commercially available inkjet printer, Regarding the degree of dispersion of each pixel,
Even though it is quite sparse, we have constructed a unique area gradation method with the idea that it is enough to identify a pattern at a distance.

It must be considered here that the area gradation method in which the area ratio of ink dots is changed to realize gradation expression must simultaneously form a hue. Specifically, it must be considered how to disperse C, M, and Y, which are the three primary colors of the color material, and ink dots of pure black K in one pixel formation region. The points of thinking for this are as follows.

[Point 1] How many halftone dots should be used to form one pixel?
In order to develop a predetermined color that a pixel should have, it is necessary to realize a fine area ratio between ink dots of each color. For that purpose, it is necessary to increase the number of ink dots forming one pixel as much as possible.

In the present invention, one pixel is formed by, for example, 13 halftone dots. The greater the number of halftone dots forming one pixel, the better the color reproducibility, but the optimum number is selected from the viewpoint of equipment and productivity. The halftone dots are ink dots that are colored by the ink supplied to one cell portion. When one pixel is formed by 13 halftone dots, each halftone dot (maximum 13 pieces) consisting of any one of CMY three basic color inks is dispersed in one pixel formation area, and further, By adding the part of the background color that does not exist, it is assumed that the entire plate surface will be mixed. The dark black ink K1 is mainly used when forming a hue having a lot of black, and the light black ink (or light gray ink) K2 is used for color adjustment.
To use.

[Point 2] Concerning the condition of side-by-side color mixture It is only the hue density that one pixel should have that is produced by the side-by-side color mixture, and the gradation expression of the whole image is expressed by the image set by a plurality of the pixels. To do. In order to emphasize the difference in color at the boundary where different colors are painted,
It is necessary to make the hue of one pixel independent of the hue of another adjacent pixel as much as possible.
By doing so, the risk of forced side-by-side color mixing due to the hue density of adjacent pixels is mitigated to some extent. Therefore, in the present invention, for the peripheral portion of the cell in one pixel forming region, and so as not to dare supplying ink. Therefore, the influence of the background color cannot be ignored, but if the background color is white, the influence of the background color can be completely ignored. Further, by using a light gray color, it is possible to obtain a certain amount of under color removal (UCR) effect.

[Point 3] Conditions for Good Color Mixing Effect In parallel color mixing, in order to obtain a good color mixing effect, 1
It is necessary to arrange the cells so that many points where color mixing is possible (hereinafter referred to as color mixing center points) can exist in the pixel formation region.

Here, in the side-by-side color mixture, the position where the color mixture center point is formed can be assumed to be a point obtained by bisecting the line segment connecting the color development center points of the adjacent dyes in the case of two color mixture. Further, in the case of three-color mixing, it can be assumed that the center of gravity (intersection point of each median line) of a triangle formed by connecting the coloring center points of three adjacent dyes is the mixing center point.

Therefore, as shown in FIG. 2B, if a large number of cells 2a are arranged so as to be arranged at an inclination angle of 45 degrees with respect to the axial direction of the gravure roll 2, it is provisionally shown in FIG. Assuming that a rectangular area made up of 3 × 3 cells surrounded by the bold line is configured as one pixel forming area, the eight cells a to h located in the inner peripheral portion of the rectangular area are affected by the adjacent outer pixels. (Pixel-mixed color) is directly received, and the color unique to the pixel cannot be independently developed.

Further, in this case, there are four color-mixing center points, that is, points 1 to 4 indicated by black circles in the figure, and all four adjacent halftone dots including the halftone dot indicated by the central cell P. Side-by-side color mixing by each color of dots will be performed. Specifically, the color mixture center point 1 performs color mixture of four colors abPh, the color mixture center point 2 performs color mixing of four bcdP colors, and the color mixture center point 3 performs color mixing of four defP colors. At the center point 4, color mixture of four colors of fghP is performed. In this case, even if an attempt is made to mix the three colors of CMY, any one of the colors will always be further mixed, so that the color mixture by CMY is influenced by another color to be added.

On the other hand, as shown in FIG. 5, if the rectangular area indicated by the thick line frame A is formed as a one-pixel forming area,
In the figure, by the 13 halftone dots indicated by symbols S1 to S13,
One pixel will be formed. In addition, in the figure, eight center points of color mixture, which are indicated by black circles and in which the colors of three adjacent halftone dots that are adjacent to each other are mixed, and four individual halftone dots, which are indicated by white circles in the figure, are adjacent to each other. There are a total of 12 color-mixing center points, which is the four color-mixing center points in which juxtaposed color-mixing is performed depending on the colors of the points.

Therefore, in the present invention, one pixel is basically formed by a plurality of (13 in this embodiment) halftone dots, and these 13 halftone dots are treated as a set of CMY ink dots. I decided. Then, the ink is intentionally not supplied to the cells located in the inner peripheral portion of the one-pixel forming region. Therefore, when considering the color development of one pixel, it is necessary to consider that the background color before printing is developed in the printed portion corresponding to the cell position in the peripheral portion where it is certain that ink will not be supplied. There is. As described above, in the present invention, the position of the ink supply point required to form one pixel is determined in advance.

Next, the cell array shown in FIG. 5 is replaced with a [5.times.5] matrix as shown in FIG. 6 in order to create the necessary print control data (described later), and the ink array The supplied cell center position is represented by "1", and the color mixture center point is represented by "0" because the ink is not supplied.

Here, with respect to the cell position indicated by "1", in principle, any one of the dark color inks C1, M1, and Y1 of CMY or the light color inks C2, M2, and Y2 is used. Supplied as. The ink supply amount is the same in each cell.

[Point 4] Regarding gradation expression FIG. 7 shows an example of a cell array according to a change in color density that can be expressed by the cell array. As shown in FIG. 7, in order to arrange the halftone dots so as not to be biased in the one-pixel forming area, a substantially point symmetric arrangement is performed with the {3,3} position, which is the center point of this rectangular area, as the center. As described above, it is necessary to determine the position of "1" (cell position for supplying ink).

If the number of "1" s is reduced, the effect of color mixing in juxtaposition is diminished. Therefore, if the number of cells to be used is determined to be 8 to 13, for example, FIGS. It is possible to express 6 levels of color density as shown in FIG.

Even when eight or more cells are used, the cell positions shown in FIGS. 8A to 8C are excluded. In the cell arrangement shown in FIG. 8A, the central portion in the pixel is omitted, and FIGS. 8B and 8C
The reason for excluding the cell arrangement shown in (3) is that the color mixing effect is low.

By expressing the six-stage color density expression shown in FIGS. 7A to 7F with both dark and light inks D and P,
12 levels of color density can be expressed. This is shown in FIGS. 9 and 10. In FIG. 9, D is a dark color ink, P is a light color ink, and n is a cell that does not supply ink. In the cell n to which no ink is supplied, the background color appears as halftone dots. When the number of cells n that do not supply ink increases, the color mixture is affected to a considerable extent. Therefore, in the present invention, K2 ink, which has little influence on the cell indicated by n, is supplied. That is, K2 is a light gray color, and when the light color inks C2, M2, and Y2 are subtractively mixed, it becomes a light gray color. Therefore, in the case of the subtractive color mixture, black used as the undercolor removal (UCR) is used. By using ink (the amount used as UCR is about 30% or less) as a light gray color, a mixing ratio relationship of C + M + Y + K2 = 1 is established, so that the degree of freedom in color mixing of CMY colors is increased.

As described above, K2 is intentionally added as a constituent color in the juxtaposed color mixture, and in the present invention,
Considering that the ground color is fully developed for one pixel by all n cells to which no ink is supplied,
It is assumed that the image is formed in the state where the ground color expression is added in addition to the gradation expression.

Next, according to the present invention, in order to make the 12 gradations shown in FIGS. 9A to 9L good, these 12 gradations are designated as dark color ink D as shown in FIG. It is supposed to be expressed by the area ratio of each of the light color inks P.
In this case, the dark and light ink densities are adjusted in advance so that the color densities of D × 7 and P × 13 are equal. By doing so, it is possible to smoothly express 12 gradations.

[Point 5] Color Development by Side-by-Side Color Mixing (Part 1) Side-by-side color mixing can be basically handled as additive color mixture as described above. FIG. 11 and FIG. 12 are views showing the area ratio of CMY supplied to each cell based on C when all 13 ink supply cells are used.

The combinations of possible area ratios of CMY inks are as follows. (1) For a single color, there are three combinations. 13C, 1
3M, 13Y (2) In the two-color mixture, there are the following combinations. “Combination of CM, MY & YC” → 36 as 12C + M, 12M + Y, 12Y + C. 11C + 2M, 11M + 2Y, 11Y + 2C.10C + 3M, 10M + 3Y, 10Y + 3C. 6C + 7M, 6M + 7Y, 6Y + 7C 5C + 8M, 5M + 8Y, 5Y + 8C 4C + 9M, 4M + 9Y, 4Y + 9C 3C + 10M, 3M + 10Y, 3Y + 10C 2C + 11M, 2M + 11Y, 2Y + 12C,

(3) In the three-color mixture, the following 66 combinations are available.・ 11C + M + Y ・ 10C + 2M + Y, 10C + M + 2Y ・ 9C + 3M + Y, 9C + 2M + 2Y, 9C + M + 3Y ・ 8C + 4M + Y, 8C + 3M + 2Y, 8C + 2M + 3
Y, 8C + M + 4Y 7C + 5M + Y, 7C + 4M + 2Y, 7C + 3M + 3
Y, 7C + 2M + 4Y, 7C + M + 5Y 6C + 6M + Y, 6C + 5M + 2Y, 6C + 4M + 3
Y, 6C + 3M + 4Y, 6C + 2M + 5Y, 6C + M +
5Y ・ 5C + 7M + Y, 5C + 6M + 2Y, 5C + 5M + 2
Y, 5C + 4M + 4Y, 5C + 3M + 5Y, 5C + 2M
+ 6Y, 5C + M + 7Y 4C + 8M + Y, 4C + 7M + 2Y, 4C + 6M + 3
Y, 4C + 5M + 4Y, 4C + 4M + 5Y, 4C + 3M
+ 6Y, 4C + 2M + 7Y, 4C + M + 8Y 3C + 9M + Y, 3C + 8M + 2Y, 3C + 7M + 3
Y, 3C + 6M + 4Y, 3C + 5M + 5Y, 3C + 4M
+ 6Y, 3C + 3M + 7Y, 3C + 2M + 8Y, 3C +
M + 9Y 2C + 10M + Y, 2C + 9M + 2Y, 2C + 8M +
3Y, 2C + 7M + 4Y, 2C + 6M + 5Y, 2C + 5
M + 6Y, 2C + 4M + 7Y, 2C + 3M + 8Y, 2C
+ 2M + 9Y, 2C + M + 10Y ・ C + 11M + Y, C + 10M + 2Y, C + 9M + 3
Y, C + 8M + 4Y, C + 7M + 5Y, C + 6M + 6
Y, C + 5M + 7Y, C + 4M + 8Y, C + 3M + 9
Y, C + 2M + 10Y, C + M + 11Y As described above, 1 + 2 + 3 + 4 + 5 + 6 + 7 + 8 + 10
There are + 11 = 66 combinations.

Therefore, when all the 13 cells forming one pixel are used, a total of 105 (3 + 36 +)
66 = 105) as combinations. This is different 3
It is considered that it is an overlapping combination that takes 13 from the number of ₃ H ₁₃
= _{3 + 13-1} C ₁₃ = 105 both can be calculated. Furthermore, the above combinations are conceivable for each case where dark and light inks are used, and as a result, 210 (105 × 2 = 210)
There are the following combinations.

[0065] [Point 6] For color development by juxtaposed color mixture (Part 2) Next, consider distributed arrangement of ink dots definitive one pixel formation area. 13 and 1
FIGS. 4 to 16 are diagrams to be compared with FIGS. 11 to 12, and show an arrangement example in the case of performing the two-color mixing and the three-color mixing using all 13 cells.

FIG. 13 shows an example of each dispersed arrangement of two color mixture, and here, for example, M halftone dots (indicated by black circles) added to the C halftone dot (indicated by white triangle) arrangement. )
However, in order not to be biased as much as possible, it is arranged so as to spread in four directions from the central part in the 1-pixel formation region ,
Moreover, it disposed so as to be possible scattered individual halftone dots is divided, is considered 12 ways of combinations as shown in FIG. 13 (a) ~ (l) .

FIGS. 14 to 16 show examples of respective dispersed arrangements of three color mixture. Here, in FIG. 13, a plurality of M halftone dots (indicated by black circles) to which the colors are added are made to remain in Y. By replacing with halftone dots (indicated by squares) in order, 3
A mixed color state is formed, and eventually 66 combinations (1 + 2 + 3 + 4 + 5 + 6 + 7 + 8 + 9 + 10 + 11 =
66) is considered. Note that the halftone dots (halftone dots of C) indicated by white triangles are omitted because their positions do not change. Furthermore, since combinations of the above are conceivable for each case where dark and light inks are used, after all, 132
(66 × 2 = 132) combinations are possible.

[Point 7] Coloring by Side-by-Side Color Mixing (Part 3) Next, in the case of using 8 to 12 cells in FIG. 9 as well as in the case of using the above 13 cells, As for the arrangement in each of these cases, halftone dots are already formed by the light gray (ground color) ink K2 at the fixed position indicated by "n".

Therefore, in the present invention, the processing is simplified by considering as follows. That is, in FIG.
If the halftone dot formed at the position indicated by “n” is C as the reference halftone dot, it is considered to be M or Y other than the halftone dot. ~ It is possible to treat as a pseudo equivalent to the three-color mixed position. Therefore, for the same cell arrangement as shown in FIGS. 13 and 14 to 16, the fixed position of n is set to K2 later.
, And the color mixing effect of K2 is represented respectively. Note that the same combinations are possible in the case where the dark color ink D is used and the case where the light color ink P is used. As described above, possible cell arrays of all CMYK color inks to be used are determined for one pixel formation region.

Next, the creation of the juxtaposed color mixture data will be described. In order to create the side-by-side color mixture data required for print control, any ink in CMY is "1", any of the two types of ink other than the one ink is "2", and the remaining ink is "2". When the matrix expression shown in FIG. 6 is performed by setting the inks of 3 ”and K to“ 4 ”, it becomes as shown in FIGS. The positions of 1 and 0 on the way are omitted because their positions do not change. The matrices shown in FIGS. 17 to 19 are applicable to the case where the dark color ink is used and the case where the light color ink is used.

Next, each of these CMYK color ink arrays is associated with the reference color development data. Here, regarding the reference color development data, FIG.
1. Based on the idea described in FIG. 12, the additive color mixture calculation is performed according to the area ratio of each ink to determine. That is, a simple additive color mixture value F is obtained by the following equation and converted into RGB data F (RGB).

(Α / 13) × C + (β / 13) × M + (γ /
13) × Y + (δ / 13) × K2 = F → F (RGB) However, α + β + γ + δ = 13. Note that R + G =
There is a relationship of Y, G + B = C, and B + R = M (complementary color relationship).

Next, F as a simple additive color mixture result value
In order to perform color matching between the color density of (RGB) and the color density of each ink ejection cell arrangement to be actually executed, the density of F (RGB) is set to 1/13, and 1
The punching power of the color-mixed pixels is weakened to F ′, and in accordance with the resolution of the display screen, the pixel matrix unit of [5 × 5] on the screen with respect to the 12 “0” positions shown in FIG. , The data value of F ′ is colored on the left half screen. A slide switch for RGB adjustment is displayed in the lower right corner of the color matching control screen.

Subsequently, for the 13 positions of "1" shown in FIG. 6, similarly, in the unit of [5 × 5] pixel matrix of the same display screen, according to the ink arrangement determined in FIG. 17 to FIG. , The CMYK two-color data distributed and arranged is colored on the right half screen. Then, this coloring state is fixed. In this case, for each color data of the inks CMYK2 to be used, the RG is used in advance in order to display it
Prepare the data converted to B data.

As described above, monochromatic images having a slight color difference are displayed on the left and right display half screens. Therefore, observe both screens while comparing them and
The color development state of the left half screen by the data value of is matched with the color development state of the right half screen by operating the slide switch for RGB adjustment. The RGB value at that time is stored as the reference color development data in association with the matrix data of the corresponding cell position. In this way, a database for coloring is constructed in which all the data RGB of the colors to be developed are associated with the corresponding cell arrangement matrix data.

Next, the creation of print control data will be described. The print control data is data in which the control content regarding "which head, which nozzle controls the opening / closing of which nozzle, drives the piezo element at what timing".

The creation is performed by the procedure shown in FIG. The color original S1 is read by the color scanner S2 to obtain RGB data S3 for each pixel. RGB data S3 for each pixel using the coloring database S4
Cell array data S5 which is ink selection data for each cell
Convert to. As a result, the color of the ink supplied to each cell is determined (S6). The cell array data S5 is decomposed into head-specific cell array data S7. The control timing is calculated corresponding to the transportation of the building board (S8),
The print control data S10 is obtained by converting the head-specific cell array data S7 into timing control data in which control timing information is added (S9).

FIG. 22 shows the nozzle arrangement of the ink jet head. In FIG. 22A, white circles and black circles indicate nozzles. Each of the dark and light recording heads is composed of two rows of nozzle lines (1) and (2). In the nozzle line (1), a large number of nozzle groups indicated by six white circles are arranged in the lateral direction. In the nozzle line (2), a large number of nozzle groups indicated by four black circles are arranged in the horizontal direction. As shown in FIG. 22B, 13 pixels form one pixel. In the present embodiment, one pixel forming area A has a length of 0.51 mm and a width of 0.51 mm.

FIG. 23 is a diagram showing a specific example of cell array data and its head-specific array data. The cell array data set for each pixel of the image to be printed on the building board is decomposed into cell array data for each head (for each ink color).

24 and 25 are diagrams showing a method of creating timing control data. As shown in FIG. 24, assuming that the entire surface (design surface) of one plate is a plane, the plate is divided into pixel regions, and the pixel region is further divided into pixels of [5 × 5] from the end in the traveling direction of the plate. With the matrix as the control unit,
Handled as control data of {i row, j column}. Based on the actual size of the plate used for printing, it is assumed that the short side has n columns and the long side has m rows.

The horizontal j-column data indicates which nozzle of the nozzle array of the ink jet head is used,
The i-th row data in the vertical direction corresponds to the cell position facing the nozzle according to the angular velocity of the gravure roll, and is data that defines the usage timing of the nozzle specified by the j-th column data.

Further, as shown in FIG. 25, pulse data is converted into each column. The start point is a time point when a predetermined time has elapsed since the time point when the ink transfer to the building board of the offset roll was started. Also, the odd and even nozzles are never turned on at the same time. A program for checking that the odd-numbered nozzles and the even-numbered nozzles are not turned on at the same time is used to check that they are not turned on at the same time when the pulse data is created.

As shown in FIG. 22, when ink is supplied using two nozzles adjacent to one cell, the two nozzles corresponding to the data of "1" are turned on. . In this way, the print control data described above is created for the nozzles of each head, and the corresponding pulse is supplied to the piezo element that drives each nozzle, thereby executing the supply control of the ink to the cells. .

[0084]

As described above, the building board printing apparatus according to the present invention can perform printing with a quality close to gravure printing or gravure offset printing on a building board without using a physical plate. . Since the building board printing apparatus according to the present invention does not require a physical plate, it can flexibly cope with small lot multi-product production.

The building board printing apparatus according to the present invention allocates a plurality of adjacent cell portions to one pixel of an image to be printed and supplies ink to each cell portion corresponding to the color of the pixel to be printed. Since the color is set, one pixel is formed by a plurality of halftone dots (ink dots developed by ink supplied to one cell portion), and C, M, Y,
By changing the area ratio of the four types of K ink dots, one pixel having a desired color density can be obtained.

[Brief description of drawings]

FIG. 1 is a schematic structural diagram of a building board printing apparatus according to the present invention.

FIG. 2 is an external perspective view of a gravure roll and an enlarged view of a roll surface of the gravure roll.

FIG. 3 is a diagram showing a specific example of arrangement of cells and arrangement of nozzles.

FIG. 4 is a diagram showing an adverse effect of side-by-side color mixing when one pixel is composed of nine cells.

FIG. 5 is a diagram showing a configuration example of one pixel according to the present invention.

FIG. 6 is a diagram that is expressed by being replaced with a matrix of the center position of each cell that constitutes one pixel.

FIG. 7 is a diagram showing a relationship between a cell position for supplying ink and density gradation.

FIG. 8 is a diagram showing an undesirable example of a cell arrangement for supplying ink.

FIG. 9 is a diagram showing a cell arrangement when performing gradation expression in 12 steps.

FIG. 10 is a diagram showing the relationship between the density of ink used when performing gradation expression in 12 levels and the number of halftone dots (cells).

FIG. 11 is a diagram (No. 1) showing the area ratio of CMY supplied to each cell with C as a reference when all 13 ink supply cells are used.

FIG. 12 is a diagram (No. 2) in which the area ratio of CMY supplied to each cell is shown based on C when all 13 ink supply cells are used.

FIG. 13 is a diagram illustrating an example of distributed arrangement of two colors.

FIG. 14 is a diagram (No. 1) showing an example of dispersed arrangement of three colors.

FIG. 15 is a diagram (No. 2) showing an example of dispersed arrangement of three colors.

FIG. 16 is a diagram (No. 3) showing an example of dispersed arrangement of three colors.

FIG. 17 is a diagram (No. 1) showing a matrix representation of juxtaposed color mixture data.

FIG. 18 is a diagram (No. 2) showing a matrix representation of juxtaposed color mixture data.

FIG. 19 is a diagram (No. 3) showing a matrix representation of juxtaposed color mixture data.

FIG. 20 is a diagram showing a color matching control screen.

FIG. 21 is a diagram showing a procedure for creating print control data.

FIG. 22 is a diagram showing a nozzle arrangement of an inkjet head.

FIG. 23 is a diagram showing a specific example of cell array data and its head-specific array data.

FIG. 24 is a first diagram showing a method of creating timing control data.

FIG. 25 is a diagram (No. 2) showing the method of creating timing control data.

[Explanation of symbols]

1 Building board printing equipment 2 Gravure roll 2a Cell part (cell) 3 Inkjet mechanism 4 Gravure roll cleaning mechanism 5 offset rolls 6 Offset roll cleaning mechanism 7 backup roll 8 building boards 31-34 recording head 35 Print control device

─────────────────────────────────────────────────── --- Continuation of the front page (56) References JP-A-11-20297 (JP, A) JP-A-10-151722 (JP, A) JP-A-10-128230 (JP, A) JP-A-9- 201564 (JP, A) JP 6-316174 (JP, A) JP 4-350654 (JP, A) JP 10-16204 (JP, A) JP 9-52536 (JP, A) Special Table 2002-503572 (JP, A) (58) Fields investigated (Int.Cl. ⁷ , DB name) B41F 16/00-17/38 B41F 9/01 B41J 2/01 B41M 1/00-3/18 B05B 12/00-13/06 B05D 1/00-7/26 E04C 2/00-2/54

Claims (6)

(57) [Claims] 1. A gravure roll that holds and rotates the supplied ink in a plurality of cell parts, an inkjet mechanism that ejects and supplies the ink to the cell parts, and a gravure roll that is rolled and contacted with the gravure roll. Corresponding to the offset roll that transfers the ink held in the gravure roll and transfers it to the building board, and assign multiple adjacent cell parts to one pixel of the image to be printed and to correspond to the color of the pixel to be printed. A building board printing apparatus, comprising: a print control unit that sets ink supplied by the inkjet mechanism to each cell unit. 2. The building board printing according to claim 1, wherein each of the plurality of cell portions is a square having the same size, and a diagonal line thereof is parallel to an axial direction of the gravure roll. apparatus. Wherein the ink jet mechanism, building board printing apparatus according to claim 1, wherein the benzalkonium be injected selectively to different ink to each of said cell portions. Wherein said ink jet mechanism, building board printing apparatus according to any one of claims 1 to 3, wherein the benzalkonium to eject ink of different concentrations of the same dye. Wherein said print control unit, peripheral in one stroke Motonai
The building board printing apparatus according to claim 1, wherein control is performed so that ink is not supplied to the side cell portions. Wherein said print control unit architecture of claim 1, wherein the controller controls so as to supply ink to the cell of more than half of the plurality of cells of the single screen Motonai Plate printing equipment.