JPS5834455A - Screen and its production - Google Patents

Abstract

PURPOSE:To eliminate a moire pattern and to reduce the roughness for a gravure screen, by using a pattern including numbers of irregular folded lines having cut parts. CONSTITUTION:The intersections (e.g., A-F) of a pattern (dotted lines) of 2- dimensional regular squares adjacent to each other are shifted at random (average shift distance: about 1/4 length of a side of a square; standard deviation of said shift distance: about 1/8 length of a side of a square; shift direction: all angles around intersections). The obtained points A'-F' are connected (solid lines) with a relation equivalent to that between original intersections. Thus a pattern including irregular squares is obtained. Then the segments of lines connecting among intersections and having smaller length than a prescribed value (shown by dotted lines) are erased to obtain a pattern. Using this pattern, a gravure screen is formed.

Description

DETAILED DESCRIPTION OF THE INVENTION This invention relates to a method of printing a gravure screen which is combined with a screen board for lithography or letterpress when a gravure printing plate is not prepared using a screen board for lithography or letterpress printing.

The transparent or opaque lines of the gravure screen of the present invention are formed into J! li has been made-1・)su,
Due to the presence of this irregularity, the first halftone dot pattern is constructed by a regularly arranged halftone dot pattern. Even when combined with a halftone positive for 17th printing or letterpress printing, no moiré pattern is produced.

Therefore, the gravure screen of the present invention can be combined with mesh substrates of any screen angle, and even for multiple mesh substrates with different screen angles, a single gravure screen can be used to print gravure printing plates. can be created.

Furthermore, the gravure screen of the present invention can also be used in a conventional gravure process, and even if a pattern with a regular pattern exists in a document, moiré will not occur between the pattern and the gravure screen.

In order to perform gravure printing, it is generally necessary to form a so-called concave concave portion on the surface of the gravure plate to form independent minute depressions for holding ink. It is often said that in order to form such minute four points, they should be formed using a soil gravure screen.Gravure screens generally have many opaque independent minute points. They are arranged regularly.When printing with two or more colors using such a gravure screen,
'j2, it becomes easier to control moiré.

-1: There is a method of performing gravure printing using a net positive for printing or letterpress printing.

In halftone positives for lithography or letterpress printing, the opaque halftone dots are each 1 r from the light area to the midtone area, but from the intermediate adjustment to the shadow area, these dots touch or This is an overlapping state.

Therefore, when creating a gravure printing plate using a net positive for planography or letterpress printing, a gravure screen is combined in order to prevent ink from flowing even in the areas from the halftone area to the shadow area. used.

In such a method, moiré may occur between the net positive and the gravure screen.

It has been said that the moiré between the net positive and the gravure screen is based on the interaction between the regular arrangement of the dots of the net positive and the regular arrangement of the patterns of the gravure screen. On the other hand, in the case of multicolor printing, multiple halftone positives corresponding to the colors to be printed on the same original are required, and the arrangement angles of the halftone dots of these halftone positives are different from each other. The reason for this is to prevent moiré from occurring between the mesh positives, and therefore the arrangement angle of the halftone dots of each mesh positive is selected so that moiré is least noticeable.

For the above reasons, in order to make the moiré between the mesh positive and the gravure screen as inconspicuous as possible in multicolor printing, conventional methods have been to Positive screen angle) K
It is common to combine a gravure screen with a suitable screen angle. Therefore, in the case of multi-color printing, it is necessary to prepare a number of gravure screens corresponding to the number of colors to be printed, or to prepare a gravure screen with a size larger than the actually required exposure area. A piece of gravure screen is rotated to obtain the appropriate screen angle for each use.

The former case requires a plurality of expensive gravure screens, and the latter has the disadvantage of requiring a gravure screen larger than the required exposure area.

Therefore, the development of a gravure screen that does not have such drawbacks is expected.

Furthermore, even in the conventional gravure process, if a pattern with a regular pattern exists in the manuscript, moire may occur between this pattern and the gravure screen, and it is necessary to prevent such moire from occurring. The development of gravure screens is also expected.

Conventional methods have been devised to prevent moiré from occurring between the mesh screen and the gravure screen. For example, rJ S Pl 4.158.567 discloses a method in which a gravure screen is not formed from the light area to the intermediate tone area. However, in this method, a negative chip is required when printing the gravure screen, and when printing the net positive chip, it is necessary to register the screen with the negative chip.

Further, a method of using a grain screen instead of a gravure screen is also disclosed in US Pat. No. 2,096,794 Specification (2). However, this grain screen is usually 10
The roughness is approximately 0.4/inch, which has the disadvantage that it feels rough in practical use, and also has the disadvantage that unevenness is likely to occur because of the large difference in area of individual cells.

Furthermore, a gravure screen to prevent moiré that may occur between the net positive and the gravure screen is manufactured by the British company No. 974884 (3 Ming + IIf).
Disclosed in store. Use of the gravure screen disclosed herein seems to be preferable because it would be possible to prevent the occurrence of moiré and there would be no large difference in the area of the individual cells. However, the pattern of this screen consists of repeating the pattern in certain units.

Furthermore, the transparent lines of the gravure screen disclosed in this British patent must have multiple types of angles including all the screen angles of the multiple mesh positives used. Therefore, although this gravure screen is useful when the screen angle of the net positive is predetermined, if the screen positive screen angle of the net positive has to be used, A separate gravure screen must be used that encompasses the appropriate angle for the bozicip.

The present invention is a gravure screen that prevents the occurrence of moire, and is a new gravure screen that is different from the above-mentioned gravure screen. This is what I'm trying to do with the screen.

Generally speaking, there are two types of gravure screens: gravure type and positive type.

A positive type gravure screen consists of a continuous transparent line segment and an opaque area surrounded by the transparent line segment, and a negative type gravure screen consists of a continuous opaque line segment and an opaque area surrounded by the transparent line segment. It consists of a transparent part surrounded by line segments.

The present invention can provide both such positive type and negative type gravure screens.

Generally, a gravure screen has a transparent portion and an opaque portion formed on a substrate such as a glass plate or a synthetic resin film. In the gravure screen of the present invention, the above-mentioned substrates are appropriately selected and used as the substrate.

Among the conventionally used gravure screens, the most common one is as shown in Fig. 'Transparent or opaque line segment in j/j direction (2)
It has a pattern in which the two are intersected.

In the case of a positive type gravure screen, the line segments in the vertical direction and the ]171 direction in Figure 1 are transparent, and the cell part (3) between them is opaque, and in the case of Lee Gataib's gravure screen The relationship between transparency and opacity is reversed.

The gravure screen of the present invention has not such a regular pattern but a completely irregular pattern.

That is, the gravure screen of the present invention is a gravure screen in which a large number of transparent or opaque line segments are formed on a substrate and the portions other than the line segments are opaque or transparent. A straight line segment consists of an irregularly bent straight line, an irregularly curved smooth curve, or a combination thereof.

In the present invention, the irregularly bent straight line or irregularly curved smooth curve is a combination of a number of line segments of a desired length with or without intervals. .

Such a gravure screen according to the present invention can provide good printed matter that does not generate moiré or has less roughness.

In the gravure screen of the present invention, the large number of transparent or opaque line segments formed on the substrate may have intersection points or branch points between these line segments, or It may not have a point or a branching point.

Furthermore, in the gravure screen of the present invention, the transparent or opaque line segments formed on the substrate have a large number of opaque or transparent opaque lines that intersect with each other and are surrounded by these line segments. It may form regular shaped points.

In this case, if the transparent line segment is an irregularly bent straight line, the number of opaque or transparent points surrounded by these line segments is irregular. becomes a polygon.

According to the present invention, a novel method for manufacturing the gravure screen as described above is provided. That is, according to the gravure screen manufacturing method of the present invention, first, the position information of a plurality of points is recorded, and based on the position information of the plurality of points, the position of the plurality of points is set as the origin, and the center is set at the origin. , place the plurality of points irregularly at V'-W positions within a certain range of desired limits and record the position information;
A number of line segments are created by connecting the positions after the displacement with straight lines and/or curves based on the post-displacement position information '4VC, and the line segments or line segments are approximated by smooth curves. The pattern with cutouts is used as the original pattern for the gravure screen.

In this case, by appropriately changing the thickness of the line segment used as the original pattern, the thickness of the transparent or opaque line segment of the gravure screen can be changed.

In one embodiment of the gravure screen manufacturing method according to the present invention, the positions of the plurality of points before the displacement are predetermined, and the connection relationships of these plurality of points are also predetermined. The positions after the displacement are connected by a straight line or a curved line in accordance with the connection relationship between the points before the displacement.

In this case, the positions of the plurality of points before the displacement are the positions of each intersection of the dimension line segments forming a repeating pattern of a large number of regular polygons, and the connection relationship of the plurality of points is the position of each side of the regular polygon. It can be made to correspond to

The regular polygon may be a regular triangle, a regular quadrilateral, or a regular hexagon.

As yet another example, the positions of the plurality of points before the displacement are the positions of intersections of two groups of straight lines arranged in parallel at equal or irregular intervals and crossed at right angles or obliquely. can be,
The connection relationship between the plurality of points may correspond to a straight line passing through the intersection.

Still another example is that the positions of the plurality of points before the displacement are the positions of intersections of three sets of straight line groups in which a large number of straight lines are arranged in parallel, orthogonally or obliquely to each other, and the positions of the plurality of points before the displacement are The connection relationship may correspond to a straight line passing through the intersection.

In yet another embodiment of the method for manufacturing a gravure screen according to the present invention, it is carried out as follows. 7'
f That is, a predetermined starting line vector is identified, a large number of moving vectors whose lengths and directions change irregularly within a predetermined range are generated with respect to the starting line vector, and the end point of the starting line vector is Recording the end point of the starting line vector as the starting point of the first movement vector, recording the end point of the first movement vector as the positional information of the first point after displacement, This point is recorded as the position information of the second point, the end point of the first movement vector is made the start point of the second movement vector, and the end point of this second movement vector is the position after the displacement of the second point. The position information of the plurality of points before the movement and the position information of the plurality of points after the displacement are recorded in the same manner. Create a line segment by connecting the displaced positions of the points with a straight line and/or a curved line according to the above order,
Thereafter, a large number of line segments created in the same manner and/or the line segments are approximated by smooth curves. One color per month, arranged horizontally.

The gravure screen and method for manufacturing the same according to the present invention include many embodiments as described above.

The present invention will be explained in more detail below.

First, the gravure screen of the present invention has cell portions (3) having a repeating pattern of regular squares as shown in FIG. It is also possible to create a pattern based on a pattern in which the shapes of individual regular polygons are irregularly changed. As explained, this is because the positions of multiple points before displacement are predetermined, and the connection relationships between these multiple points are also determined in advance, and the position of the points after displacement is determined by the straight line. This corresponds to the case where the connection is performed in accordance with the connection relationship of the points before the displacement.

In this case, in order to obtain the gravure screen of the present invention, positional information of each intersection of line segments forming a regular polygonal repeating pattern is recorded. Fig. 2 is an enlarged view of a part of No. 101, but in this case, each (Al C
l1l (C"l (I)l (Tsu) (goods)) is the intersection point.

Next, a new point f (1'l [fσ) f (F, f (
1.Determine the end position 1~Record 7-)O Based on the position information of this new point, calculate the line segment (10) (I If (12) (20) that forms the above-mentioned rectangle)
C2]1 f22) (23) A deformed rectangular pattern is formed by connecting the new points in vc correspondence. FIG. 6 shows a rectangular pattern deformed in this way.

By moving the other intersection points in this way, a pattern in which the regular square is irregularly deformed is no longer formed.

FIG. 4 thus shows a pattern of quadrilaterals which are irregularly deformed by moving the positions of the intersection points of the regular quadrilaterals shown in FIG.

The lengths of the line segments forming each side of the rectangle thus transformed change irregularly, and their inconsistency j(1°) is different from the rule (' IgK
(?＜Exists.

When "moving the intersection point", it is done within a predetermined range, but this is based on the requirement that the size of the cell area be as uniform as possible.In order to satisfy this requirement, For example, the distance to move the intersection is assumed to be about 1/4 of the length of one side of the regular polygon, and the standard deviation is about 1/8 of the length of one side of the regular polygon. , the direction of movement is cf~ around the original intersection
It is possible to employ means for uniformly taking directions up to 360°.

In order to further equalize the area of the cells, for example, the distance r-:Lliie (-e; length of one side of a regular polygon) in which the intersection points are moved is set to a constant Vrc+-, and the direction in which the intersection points are moved is 0°, 15°, 30°, etc.
. . . The values of 545° in 15° increments should be taken evenly, and each intersection point should be moved irregularly within this limit. In such a case, the area of the cell after the change changes from one-half to twice the area VC of the original cell.

No. 5N shows another example of a pattern of squares that are irregularly deformed by similarly moving the positions of the intersections of regular squares.

In the case of Fig. 5, by setting the movement distance of each intersection to a probability variable whose maximum value is 0.71 times the side of the original pattern, the area of the regular rectangle of the original pattern is 4
This corresponds to an example of a screen pattern having an area of 00.

In the present invention, parts of the modified polygonal pattern are made transparent and other parts are made opaque.
If you do the opposite, it becomes a positive type gravure screen, and vice versa, it becomes a negative type gravure screen. Which one to obtain may be selected as appropriate.

As described above, the gravure screen of the present invention is constructed such that the points of the opaque or transparent cell portions are polygons having the same number of angles, and the transparent or opaque lines forming this polygon are The length of minutes varies irregularly within a predetermined range.

The gravure screen of the present invention is not limited to a rectangular pattern, but may have a triangular pattern,
Furthermore, it can also be used in the same way for hexagonal patterns.

Furthermore, the gravure screen of the present invention can also utilize a rectangular, rhombic, etc. pattern in addition to regular polygonal repeating patterns.

Such a pattern is formed by orthogonally or obliquely intersecting two sets of straight lines in which a large number of straight lines are arranged in parallel. FIGS. 6 to 8 2) show examples of patterns in which two sets of surface lines 11t as described above are orthogonally or obliquely crossed.

In the patterns of FIGS. 6 and 8, the intervals between the straight lines in each straight line group are equal. On the other hand, in the seventh quotient pattern, the intervals between the straight lines are unequal.

Furthermore, the gravure screen of the present invention can also utilize a pattern in which straight line groups 3Ili1'1 in which a large number of straight lines are arranged in parallel are orthogonal or oblique to each other.

FIG. 9 shows an example of such a pattern.

2 or 6 groups of parallel straight lines as shown in ``2'' are orthogonal or the remaining 1
The gravure screen of the present invention can also be obtained by utilizing the pattern obtained by the process in the same manner as described above.

However, in the case of patterns that are not regular polygons such as those shown in FIGS. 6 to 9, the distance between each intersection point is different in the horizontal direction and the vertical direction, so the position of the intersection point is When displacing irregularly, it is preferable that the irregularity be different from that of a regular polygon.

For example, in the case of the pattern shown in Figure 6, the intervals between the groups of straight lines in the vertical direction are all equal distances, and the intervals between the groups of straight lines in the horizontal direction are all equal distances (Yl, and the values of X and Y are In such a case, the irregularity that displaces the position of the intersection of each straight line of the pattern is made different in the horizontal and vertical directions.In other words, the position of each intersection is determined by the displacement in the horizontal and vertical directions. For example, limit Y to within ±7 and ±7, respectively.

Figure 10 shows the amount of displacement in the horizontal and vertical directions. It is limited to within ±7,
Randomly generate the values D1±02, ±04, ±06.108, ±1.0, and multiply the generated values by 2' 2VC by 1~Nezumi A, 13, C
...... By displacing the position of each intersection of the digits, A',
In this example, find the position of t', ge...1' and connect these points A7.

FIG. 11 shows an example of a pattern obtained by modifying the pattern of FIG. 6 in this manner.

In the case of the pattern shown in FIG. 7, the intervals between the straight lines in the group of straight lines in the vertical direction are also random, and the intervals between the straight lines in the group of straight lines in the horizontal direction are also random. In this case as well, the position after displacement is determined by randomly setting the amount of displacement within the limit of a displacement of less than half the interval between each straight line, and the positions after displacement are connected by line segments.

FIG. 12 is an example of a pattern in which the position of each intersection point is displaced in this way.

In the above explanation, the connection relationship between the positions of each point before displacement is the case where the connection relationship is set for all line segments passing through each point before displacement. It may be set to only one group of straight lines passing through the intersection. In this case, in the pattern that connects the points after the displacement, no intersection occurs between the line segments. FIG. 13 shows an example of such a pattern. In the 13th south, the positions of the intersections of the repeating patterns of regular squares are irregularly displaced as described above, and then only the lines corresponding to the vertical lines of the squares are combined. Note that FIG. 14 shows, for reference, a pattern in which lines corresponding to not only the vertical direction but also the vertical and horizontal directions are combined.

Generally, in order to perform gravure printing, square,
It is said that it is necessary to form cells in shapes such as rectangles, hexagons, and semicircles. However, in the case of the gravure screen of the present invention having a pattern as shown in FIG. 13, although complete cells as described above are not formed, printed matter without ink flow can be obtained.

In the case of the gravure screen of the present invention in which irregularly bent line segments are arranged in one direction as shown in Fig. When taking into account the vertical lines, the vertical lines are irregularly repeated, approaching each other, touching each other, and separating at certain intervals. FIG. 15 is an explanatory diagram of the state of an actual gravure screen based on the pattern of FIG. 13.

When a gravure plate is created using such a gravure screen, even if the concentration of Bogitib is the same, it is difficult for the corrosive liquid to enter the areas where the distance between the transparent lines is close, and therefore the corrosive liquid is difficult to enter during corrosion. The depth of corrosion in the parts is shallow (furthermore, the parts where the transparent lines are in contact are not corroded. In this way, in the parts where the transparent lines are close to each other or in contact, compared to the parts where the transparent lines are far apart) It is either shallowly corroded or not corroded. Therefore, the ink flows in that area, and according to the gravure screen of the present invention, it becomes transparent in the vertical direction as shown in FIG. Prints with no ink flow can be obtained even if there are only lines.

In the embodiments of the present invention described above, the original pattern of the gravure screen is created by displacing the position of each intersection of the polygonal pattern.

In another embodiment of the invention, as already mentioned above, a gravure screen is made as follows. That is, a predetermined starting line vector is set, a large number of movement vectors whose lengths and directions change irregularly within a predetermined range are generated with respect to the starting line vector, and the end point of the starting line vector is set to a first point. , record the end point of the starting line vector as the starting point of the first movement vector, record the end point of the first movement vector as the position information after the displacement of the first point, and record this point as the position information after the displacement of the first point. The end point of the first movement vector is recorded as the position information of the second point, and the end point of the second movement vector is recorded as the position information of the second point after displacement. At the same time, the position information of the sixth point is recorded, and the position information of the plurality of points before movement and the position information of the plurality of points after displacement are recorded in the same manner. Line segments are created by connecting the positions after the displacement with straight lines and/or curves according to the above order, and then a large number of line segments created in the same manner and/or line segments that are approximated by smooth curves are used as described above. The starting line vectors are arranged vertically and/or horizontally at predetermined intervals.

Next, such an embodiment will be specifically described with reference to the drawings.

In order to obtain a gravure screen according to the present invention, it is necessary to create its original pattern. This original pattern can be obtained as follows.

First, as shown in FIG.
). A movement vector whose length and direction change irregularly within a predetermined range is generated for this starting line vector (4).

By continuously generating a large number of movement vectors 29- thus generated, an irregularly bent line segment pattern is formed. FIG. 17 shows the line segment pattern (5) obtained in this way. Next, multiple line segment patterns (5)
The line segment pattern (5
) form a crossing pattern. Iab-th shows an example of the crossover pattern obtained in this way. In the figure, patterns indicated by orthogonal dotted lines indicate orthogonal patterns of a conventional gravure screen. In order to arrange a large number of line segment patterns in the vertical and horizontal directions so that the starting line vectors are at predetermined intervals, for example, as shown in FIG. 19, a large number of starting line vectors (4
) are arranged at predetermined intervals, and a movement vector is generated for each starting line vector (4) to form a multiple line segment pattern (5) as shown in FIG. An intersecting pattern can be created by creating two sets of line segment pattern arrays and intersecting them so that the starting line vectors are orthogonal.

Alternatively, a large number of line segment patterns (5) may be created independently and arranged in the vertical and horizontal directions so that the starting line vectors are at regular intervals to form a crossing pattern.

If only one set of line segment patterns shown in FIG. 20 is used, a pattern similar to the pattern shown in FIG. 13 can be obtained, and this pattern can also be used as an original pattern for a gravure screen.

The line segment pattern (5) is irregularly bent. The length by which the line segment pattern (5) is bent is irregular within a predetermined range, and the direction in which it is bent is also irregular within a predetermined range. Irregularities in the length and direction of bending of the line segment pattern (5) should be within a predetermined range.For example, if the average size of the cells is 100μ, 1
00μ and a Gaussian distribution with a standard deviation of 20μ, and the bending angle is a Gaussian distribution with a standard deviation of 20° and an average angle of 0° when the direction of the starting line vector is 0°. It is possible to adopt means such as controlling the movement vector using a random variable.

Of course, it is not limited to these values (it goes without saying that various values can be taken).

Furthermore, other means may also be used, for example, with respect to the starting line vector, γ=, 4cos, θ, θ=[0°±15°,
±30°], where Numa is a constant (for example, the length of one side of a cell in a conventional grid screen), γ is the length of the movement vector, and θ is the angle of the movement vector with respect to the starting line vector θ°
, ±15°, and ±30' appear as 111, a movement vector may be generated as a random variable to continuously take the negative angle, and a line segment pattern may be formed. In this case, the variation in cell area can be further reduced a).

In the explanation so far, the case where the line segment connecting the points after displacement is a straight line has been mainly taken up, but it may be a curved line instead of a straight line, and it may be a particularly smooth curved line. Alternatively, after the displaced points are connected with a straight line, the line segment obtained by combining the straight lines may be approximated by a smooth curve. In this case, it is preferable that the approximated curve be as close to the original line segment as possible;
It can be approximated by a higher-order equation such as the following curve. The curve to be approximated may be formed with a restriction so that it passes through the position of the point after displacement (or it is not necessary to apply such a restriction.Furthermore, it may be formed as a pattern that combines straight lines and curved lines). Good too.

As described above, when the pattern for obtaining a gravure screen is formed with smooth curves, the degree of mold and roughness can be further reduced compared to a grained screen.

For example, gravure screens with a pattern of irregularly bent straight lines in which points after displacement are connected with straight lines are shown in FIGS. 4, 5, 11, 12,
As can be understood from Figures 14 and 18, there are cases where the line segments intersect at an acute angle, and the cells in that part are not corroded during the corrosion of the gravure plate ((, therefore, the cells in that part are This is because the cells do not have sufficient depth, making it difficult for ink to be transferred to the printing substrate during printing, but in the case of a smooth curve, such a tendency is reduced.

Although gravure screens with irregular patterns can be obtained by the various methods described above, moiré does not occur when these gravure screens are used with halftone positives for planography or letterpress to produce gravure printing plates. Furthermore, it is less rough than a sandy screen.

Furthermore, as mentioned above, a gravure screen with an irregular pattern has less roughness than a grained screen, but if a pattern with smooth curves is used, the roughness is reduced as already mentioned. However, the degree of roughness can also be reduced by other methods.

In the case of a gravure screen with an irregularly shaped pattern as described above, the area of the cell portion surrounded by transparent or opaque line segments differs between each cell and is not uniform. do not have. In this case, cell portions with small areas in the pattern may disappear or have extremely small areas in actual gravure screens.

Fig. 21 shows an example of a gravure screen pattern according to the present invention, and Fig. 22 shows that when the pattern of Fig. 21 is used as a gravure screen, small cell portions may disappear or become extremely FIG. 3 is an explanatory diagram of an example of a case where the cell becomes a small cell.

As shown in Figures 21 and 22, if the area of the cell part in the original pattern is small, in the gravure plate, no cells may be formed at all in that part, and the ink will not be formed in this part. In some cases, the ink does not transfer to the printing substrate at all, and in some cases, the cells are small so that a sufficient cell depth cannot be obtained and the ink is not sufficiently transferred to the printing substrate).

Therefore, this kind of thing tends to give a feeling of roughness.

In order to reduce such roughness, the purpose can be easily achieved by sacrificing the irregularity of the points to be displaced to some extent, but this will easily cause moiré. If this is attempted, it is difficult to achieve uniform cell area, and roughness is likely to occur.

can be adopted to reduce the above-mentioned disadvantages.

As an example of this means, a modified rectangular pattern as shown in FIG. 5, which is a modified rectangular pattern as shown in FIG. 1, will be described in detail. In other words, in this case,
After forming the deformed rectangular pattern as described above, the area of each deformed rectangle is determined a). Any method may be used to find the area of this deformed rectangle. For example, in the case of the deformed rectangle KLMN as shown in Fig. 26, each office mark is
((x+, y+), fノ (X 2 ,,')'
2), M(X3.Y3), N(x4,
ya), its area S can be calculated using the following set of sums.

S=(m;1x(x+,xz,x3.xll)-mul
(x+, xz, x3.x4) 1m1 ""CY'+'
5"rY'+Y')"J,Y' pY 2vY'
1. Y') 1-21 1x+-X41 ely
I-Y4 l-1-l Xn-XI しI)'2
)'+111x3-x>1slyx-y21+1x4
-x3 and Iy4-ysll If the area of the irregular polygon thus calculated exceeds a predetermined range, for example, the area of the original regular polygon exceeds a predetermined range or the area exceeds a predetermined range. If it is small, the irregular polygons are divided or merged. This splitting and merging process is
This refers to the work of connecting non-adjacent vertices of the irregular polygon and the work of erasing one side of the irregular polygon, respectively, and the selection of the vertices and the selection of the sides are based on new Surface finishing of irregular polygons must be carried out under conditions that do not exceed a predetermined range.

FIG. 24 is a drawing for explaining the situation in which area restrictions are applied to the group of irregularly deformed rectangles in FIG. The line segments drawn as thick lines indicate the line segments that will be newly connected through the division process.

Figure 25 shows a pattern that has been subjected to the work to limit the area in this way. They form a group.

As is clear from FIG. 5, even if the original regular square is only transformed, the pattern remains a square after the transformation.

In other words, the number of angles of the original polygon and the transformed polygon are the same. The same applies to the word triangle and hexagonal patterns.

On the other hand, as is clear from FIG. 25, the deformed pattern after applying the area restriction includes polygons with various numbers of angles. The shape of the polygon is completely irregular, and the area of this polygon is within a predetermined range.

Figure 26 shows the area distribution state of the irregular polygon shown in Figure 5 (curve a in □□□) and the area distribution state of the irregular polygon with the area restriction shown in Figure 25 ( It is a graph showing curve 1)) in N. It can also be seen from FIG. 26 that in the irregular polygonal pattern shown in FIG. 25 with area restriction added, a reduction in roughness can be obtained.

In this way, for irregular polygons with area restrictions,
As you can see in Section 25 (2), the irregularity is increasing. This is because, as shown in Figure 24, by removing the line segment indicated by the dotted line, a continuous line segment is divided, and a state in which polygons with different numbers of angles coexist is created. , this is due to the fact that

It is more efficient to create a modified polygonal pattern with area restrictions as described in 2) using a machine. It is also possible to create a pattern and reduce it.

The modified polygonal pattern obtained by applying area restriction in this way is used as an original pattern of transparent or 1:t-opaque line segments for a gravure screen.

The gravure screen obtained in the above manner has opaque or transparent cell portions containing polygons with different numbers of angles, and transparent or opaque line segments forming these polygons. (The length varies irregularly within a predetermined range).

Furthermore, the area of the cell portion of the gravure screen obtained in two series varies irregularly within a predetermined range.

The gravure screen having a cell portion within a predetermined area as described above is not limited to starting from a square cell shape, but may also be a triangular one. The same procedure as for the cell shape may be used. Furthermore, in the case of a hexagonal cell shape, a '1'' filter can be manufactured in the same manner.

The gravure screen obtained as described above does not cause moiré because its transparent or opaque line segments change irregularly, and the area of the cell portion is within a certain range. It has the effect of causing less unevenness and roughness than sand cleaning.

Furthermore, by applying the above-mentioned means, it is possible to obtain a gravure screen with a smaller cell area variation rate than a pattern using a pattern in which only the positions of the intersection points of regular polygons are changed, as shown in FIG. As a result, the ink transferability (in the cells formed on the gravure cylinder) is improved compared to the gravure screen obtained using the pattern shown in the figure. This has the effect of eliminating the roughness of the screen.

Historically, compared to the gravure screen obtained using the pattern shown in FIG. , the effect of preventing moire is further improved, and it also contributes to the provision of printed matter with less roughness.

In the above explanation, the roughness of the irregular pattern is reduced by reducing the cell area of the deformed pattern and applying the process so that the cell area falls within a predetermined range.

The present invention solves the roughness of irregularly patterned gravure screens by using the following two methods in combination, that is, dividing or merging cell portions based on area, or curving line segments, or using Inno 1. It is something that should not be done.

That is, according to the present invention, it is possible to reduce roughness by providing notches in the various irregular line segments that have been described below.1 A first aspect of the present invention According to the above, when multiple line segments formed by connecting points after displacement have intersection points, if the line segments connecting each intersection point are short, that part is considered a notch. Zeru.

That is, calculate the length of the line segment that connects each intersection, and if the length of each line segment is shorter than a predetermined length, reduce the roughness by erasing that line segment. Fig. 27 shows the part of the pattern shown in Fig. 14 in which the length of the line segment between each intersection point is shorter than a predetermined length with a dotted line, and that part is the line segment to be erased. be. As can be understood from the pattern in FIG. 27, short line segments often appear when relatively small cell portions are formed or when ff+1 long cell portions are formed.

As can be seen from FIGS. 21 and 22, in a gravure screen formed based on a pattern having such cell portions, the cell portions may disappear or
This results in an extremely narrow cell. Therefore, in the case of a gravure plate, that part is either completely corroded or not easily corroded, which reduces the transfer of ink to the printed material and causes a reduction in roughness, as described above. 27th
According to the figure, it is understood that the cause of the roughness is reduced by erasing the line segment of the dotted line portion.

According to still another embodiment, when a large number of line segments formed by combining positions after displacement have intersection points, the line segments are erased by a predetermined length from each intersection point. Reduce the roughness by.

FIG. 28 is an example of a pattern formed in this way, and in the pattern shown in FIG. 14, line segments radiating from each intersection point of each line segment are erased by a predetermined length. It shows an example of a sesheta no ku turn.

The length to be erased is preferably on the order of % to % of the distance between each point before displacement. The predetermined length to be erased may vary irregularly.

As another example of creating lino missing portions by erasing each line segment by a predetermined length, FIG. 29 shows, for example, a pattern formed by the movement vector described above.

In the example shown in Figure 29, °C has each moving pect;
In addition to or in addition to this, a notch portion of a predetermined length may be provided in each line segment at a portion where each line segment intersects, with each line segment as the center.

In the example shown in FIG. 281, notches are provided at both ends of the short line segment connecting each intersection.
A notch may be provided at one end.

FIG. 30 shows an example in which a notch is provided only at one end of a short line segment between each intersection of the pattern shown in FIG. 14.

Another example of providing a notch in each line segment is when a large number of line segments formed by combining the positions of points after displacement have intersection points, and all of the lines are centered around each intersection point. Rather than providing cutouts in line segments (it is possible to provide cutouts only in some line segments).

That is, since the purpose of providing the notches in each line segment is to reduce roughness, the notches can be selectively provided in areas where roughness is likely to occur7.
).

In cases where roughness is likely to occur, the area of the cell portion surrounded by line segments forming the pattern of the gravure screen is small, or the angle at which the line segments intersect is acute, or the intersection of the line segments This is the case when the distance between the parts is short, and roughness can be reduced by selectively providing a notch in such a part.

In this case, calculate the area of each cell part, or calculate the angle between each line segment at each intersection, or further,
The length of the line segment between each intersection is calculated, and a notch is provided in each line segment only when the calculated value is smaller than a predetermined area, a predetermined angle, or a predetermined length range. Make it. Which line segment should be provided with a notch is determined by choosing the shortest line segment that passes through each intersection, or the shortest line segment that passes through each intersection.
It is preferable to select the shortest one depending on the shape of the pattern.

The roughness of the gravure screen can be reduced by the various methods described above.

It is also possible to combine the various methods mentioned above.

45- For example, in a pattern in which cell portions are merged and/or divided so that the area of the cell portion is within a predetermined range, the angle formed by each line segment at each intersection point is further set to a predetermined value. If the angle is smaller than , a notch may be provided in the line segment.

31N and 32 show examples of patterns subjected to such processing, and in FIG. 31, the predetermined angle is 45
Figure 32 shows the case where the angle is set to 60°.

As described above, when the treatment for reducing roughness is carried out, not only does the roughness decrease, but also the center of gravity of each cell moves, which increases the irregularity of the pattern and prevents the occurrence of moiré. Further decrease.

Furthermore, patterns that have been treated to reduce roughness include a method in which the connection relationship after displacement of a plurality of points corresponds only to a predetermined group of straight lines, and a method in which the area of the cell portion is made to correspond to a predetermined group of straight lines.
A pattern such as the one shown in FIG. 33, which combines the method of making it within the range, is also acceptable.

Figure 33 shows the pattern shown in Figure 14 after merging the cell parts so that the area of the cell part falls within a predetermined range. This figure shows a gravure screen pattern based on a pattern in which only 1-lo line segments are combined. Such a gravure screen is shown in FIG. 15 (compared to the gravure screen, the degree of moire generation is reduced by -Jd, and the degree of roughness applied to printed matter is also reduced).

Although it is more efficient to create the irregular pattern obtained as described above using a computer, it is also possible to manually create an enlarged pattern and reduce the size.

In the present invention, the irregular pattern thus obtained is used as an original pattern of transparent or opaque line segments for a gravure screen.

Various means can be used to obtain a gravure screen using the original pattern.

For example, an electronic dividing machine is used to process calculations in an irregular pattern, and the data from the calculation results is used to control an automatic engraving machine or the like to scribe a transparent glass plate that has been subjected to the necessary processing.
A method of creating a gravure screen using a normal method can be adopted.

Alternatively, an irregular pattern can be subjected to a cutting process using a computer, and the data of the division result can be used to control an exposure device to form an output on a photosensitive film to form a gravure screen.

Or use a drafting device based on the data of the calculation results.
A gravure screen may be obtained by forming an irregular pattern on a paper or the like using J control, and forming this pattern on a transparent film or glass plate using a photographic method or other means.

In the present invention, the original pattern may be created with the same dimensions as the final product, but if line width and accuracy are taken into account, the original pattern may be enlarged to a certain extent and then photographed in a reduced size to be used as a gravure screen. .

In order to obtain a gravure screen of the required size, the memory capacity is large (and the load such as processing time is too large).If the load such as processing time is too large, the connection may be made by multiple exposure of the original pattern.

In this case, it is necessary to set the Yi mark of the line segment pattern in the X direction and the X coordinate of the line segment pattern in the Y direction at the joint so that they take constant values.

As described above, according to the present invention, a gravure screen having an irregular pattern is obtained, and this screen can be used in combination with a lithographic or letterpress net positive to create a gravure printing plate. No moiré.

Furthermore, according to the present invention, it is possible to reduce the roughness of printed matter even with a gravure screen having an irregular pattern.

Furthermore, the gravure screen of the present invention can also be used in a conventional gravure process, and even if a pattern with a regular pattern exists in a document, moiré will not occur between the pattern and the gravure screen.

Although the present invention has been described in the case of a gravure screen, it can also be applied to letterpress and planographic screens in addition to gravure screens.

[Brief explanation of the drawing]

Fig. 1 shows a pattern of transparent or opaque line segments of a conventional gravure screen, Fig. 2 shows a partially enlarged view of the gravure screen of Fig. 1, and Fig. 3 shows a pattern of transparent or opaque line segments of a conventional gravure screen. Figure 4 shows a pattern in which line segments are deformed; Figure 4 shows a square pattern in which the positions of the intersections of the regular square pattern shown in Figure 1 are irregularly displaced; Figure 5 shows a regular square pattern. 1 to 6 show other examples of rectangular patterns in which the positions of the intersection points of 50- Figure 8 shows an example of a pattern in which two groups of straight lines are arranged in parallel at irregular intervals and are perpendicular to each other. Figure 9 shows an example of a pattern in which two groups of straight lines arranged in parallel at equal intervals intersect with each other. Figure 10 is a diagram for explaining the restrictions when irregularly displacing the position of each intersection point of the pattern shown in Figure 6; Fig. 12 shows a pattern obtained by deforming the pattern of Fig. 7, and Fig. 13 shows a pattern obtained by irregularly displacing the intersection points of the repeating pattern of regular squares. Figure 14 shows a pattern in which only the lines corresponding to the vertical lines of a regular square are combined, and Figure 14 is a pattern in which irregularly displaced points used to form Figure 13 are combined vertically and horizontally. is the explanation N of the gravure screen, and FIG.
Figure 17 shows an irregularly bent line segment pattern with many consecutive moving vectors, and Figure 18 shows a line segment pattern with many consecutive moving vectors. An example of an original pattern used for a gravure screen formed by a line segment pattern bent according to the rules is shown. The second oty+ is an explanatory diagram 1 in which a large number of irregularly bent line segment patterns with a large number of continuous movement vectors are arranged. Fig. 21 is a gravure screen pattern σ) As an example, Fig. 22 shows that when the pattern shown in Fig. 21 is used as a gravure screen, small cell parts disappear (1-).
An example of a case where the cell becomes small in the evening is shown, and the 23rd [T11]
For example, it is an explanation N of how to divide the area of an irregular rectangle, and FIG. Figure 25 shows a pattern in which the area 11i11 limit is added to the 24th n 1 by 1 j, and Figure 26 shows the distribution of areas of polygons shown in Figure 5. FIG. 27 is a graph showing the area distribution state of an irregular polygon with the area restriction shown in FIG. 25 added, and FIG. The part whose length is shorter than the predetermined length is shown by a dotted line, and Fig. 28 shows a pattern in which a notch is provided in the line segment shown in Fig. 1 and Fig. 14. FIG. 18 shows a pattern in which the line segment shown in FIG. FIG. 63 shows a group of straight lines in the vertical direction similar to FIG. 16, which is obtained by merging the cell portions of the pattern shown in FIG. 14 so that the area of the cell portions falls within a predetermined range. A gravure screen pattern based on a pattern combining only line segments corresponding to f. (1)...Vertical transparent or opaque lines (2)
...Horizontal transparent or opaque lines (3)...
Cell portion (a)... Starting line hector (5)... Line segment pattern Patent applicant Toppan Printing Co., Ltd. Figure 1 11 Figure 2 Figure 3 F' / Figure 4 Figure 5 Figure 8 Figure 9 Figure 10 Figure 11 Figure 12 Figure 13 Figure 1 Ki Figure 19 Male Figure 20 Figure Flute 21 Figure 22 Figure 23 M (Xl, 'Jyo) 2 Figure 2 r-) ■ Fig. 26--→Glossy Fig. 30 Fig. 32 Fig. 33

Claims (1)

[Scope of Claims] (1) In a screen composed of a large number of transparent or opaque line segments formed on a substrate and opaque or transparent parts other than the line segments, A line segment consists of an irregularly bent straight line and/or a smoothly curved irregular curve, and all or part of the irregularly bent straight line and/or smoothly curved irregular curve Screen 0 characterized by having a notch in the (2) Record the positional information of a plurality of points, and based on the positional information of the plurality of points, set the position of the plurality of points as the origin, and set the position of the plurality of points as the origin. Displace the plurality of points irregularly within a range given a desired limit, record the position information, and combine the positions after the displacement with a straight line and/or a curve based on the position information after the displacement. A method for manufacturing a screen, characterized in that a large number of line segments are created, and the line segments or the line segments approximated by smooth curves are provided with cutouts and used as the original pattern of the screen. . (3) The positions of the plurality of points before the displacement are predetermined, and the connection relationships of these plurality of points are also predetermined, and the straight line and/or curve of the position after the displacement is determined in advance. 3. The method of manufacturing a screen according to claim 2, wherein the connection is performed in accordance with the connection relationship of the points before the displacement. (4) Set a predetermined starting line vector, generate a number of moving vectors whose lengths and directions change irregularly within a predetermined range with respect to the starting line vector, and set the end point of the starting line vector to the first The end point of the starting line vector is recorded as the position information of the point, the end point of the starting line vector is set as the starting point of the first movement vector, the end point of the first movement vector is recorded as the position information after the displacement of the first point, and this point is recorded as the position information of the second point, the end point of the first movement vector is made the start point of the second movement vector, and the end point of this second movement vector is recorded as the position information of the second point after displacement. I7 record-f'Z, along with the third
The positional information of the points is recorded in I-, and the positional information of the plurality of points before movement and the positional information of the plurality of points after displacement are recorded in the same manner, and the displacement of these plurality of points is recorded. Line segments are created by connecting the subsequent positions with straight lines and/or curves according to the above order, and the subsequent positions are created in the same manner (- many line segments and/or
Alternatively, line segments obtained by approximating the line segments with smooth curves are arranged vertically and/or horizontally so that the starting line vectors are at predetermined intervals! IS
A method for manufacturing a screen according to claim 2. (5) The positions of the plurality of points before the displacement are the positions of each intersection of line segments forming a repeating pattern of a large number of regular polygons, and the connection relationship Q of the plurality of points is also the position of each side of the regular polygon. A method for manufacturing a screen according to claim 2, characterized in that the method corresponds to the following. (6) The method for manufacturing a screen according to claim 5, wherein the regular polygon is any one of a regular triangle, a regular quadrangle, and a regular hexagon. (The positions of the plurality of points before the displacement of the force are the positions of intersections of a number of straight lines, and the connection relationship of the plurality of points corresponds to a straight line Q passing through the intersections (7). !1"
F. A method for manufacturing a screen according to claim 6. (8) The positions of the plurality of points before the displacement are determined by a number of straight lines.
Six sets of straight lines arranged in yF rows are orthogonal to each other or ('',
It is the position of the intersection point where they intersect, and the connection relationship of the plurality of points corresponds to a straight line passing through the intersection point! 1) A method for manufacturing a screen according to claim 3. (9) Calculate the area of the figure surrounded by Jlv by multiple line segments formed by combining the positions after the displacement.
1 Compare whether the area is larger than a predetermined area, and if it is smaller than a predetermined surface area, delete one or more line segments constituting the figure and combine it with the adjacent figure. f71
and/or, if the area is as large as a circumferential area of 61 ni, divide the figure to form a 1'-lo line segment, thereby transforming the line segment formed by combining the positions after the displacement. The feature is that this transformed line segment is used! I1. i/r: A method for manufacturing a screen according to claim 3. (lO) When multiple line segments formed by combining the positions after the displacement have intersection points, calculate the length of the line segment connecting each intersection point to Q, and calculate the length of the line segment connecting the intersection points. 3. The method of manufacturing a screen according to claim 2, further comprising the step of erasing the line segment between the intersection points if the length is shorter than a predetermined length. (11) A patent characterized in that, in a case where a large number of line segments formed by combining the positions after the displacement have intersection points, the line segments are erased by a predetermined length from each intersection point. A method for manufacturing a screen according to claim 2 TfI. (12) When a number of line segments formed by combining the positions after the displacement have an intersection point, calculate the angle formed by the line segments at the intersection point, and calculate the angle formed by the line segments at the intersection point, and forming said angle if it is smaller than 2
3. The method of manufacturing a double sided fabric IJ-5- according to claim 2, characterized in that one or both of the line segments of the book are erased by a predetermined length from the intersection. (13) Calculate the surface area of the figure surrounded by multiple line segments formed by combining the positions after the displacement, and compare whether the area is larger than a predetermined area. , if the area is smaller than a predetermined area, the line segment is erased by a predetermined length from the intersection point at one or more intersections in the figure of the line segments constituting the figure. A method for manufacturing a screen according to claim 2. (14) In the case where multiple line segments formed by joining the positions after the displacement have intersection points, if the line segment connecting each intersection point is shorter than a predetermined length, the intersection point 3. The method of manufacturing a screen according to claim 2, wherein the line segment between the intersection points is erased by a predetermined length from the intersection point in one or both of the intersection points.