JPH0325769B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION It is well known to use a gravure screen when producing a gravure printing plate. The most common type of gravure screen is an orthogonal screen as shown in FIG.

Figures 1a to 1d are partially enlarged explanatory diagrams of orthogonal screens, and when Figure 1a corresponds to 175 lines/inch, Figures 1b to 1d each correspond to 200 lines/inch.
This corresponds to lines/inch, 300 lines/inch, and 500 lines/inch. In FIG. 1, the shaded portion is an opaque portion 1, and the other portions are transparent line segments 2. The purpose of such a gravure screen is to create an ink pocket (usually called a cell, henceforth referred to as a cell) for forming an image on a gravure printing plate. In FIG. 1, an opaque portion 1 corresponds to a cell, and a transparent line segment 2 corresponds to a wall (called a dote) for forming this cell. In this way, by inverting the gravure screen where the part for forming the dote is the transparent line segment 2, the part for forming the dote becomes an opaque line segment, and the part for forming the cell is transparent. A gravure screen is also used depending on the plate-making method.

As mentioned above, gravure screens include one in which the part for forming dots is a transparent line segment pattern and the part for forming cells is opaque;
There are two types, the opposite case, and the former case will be explained below as an example for the sake of simplicity, but the present invention naturally includes the latter case as well. In addition, in the following explanation, the transparent line segment 2 for forming the dote may be referred to as the white line.
The opaque portion 1 is sometimes referred to as a cell.

By the way, the following ()~ are used to express the characteristics of gravure screens.
Items in parentheses are listed.

() Shape of cell section Usually, a square or a square with rounded corners, a rectangle, or a round point is used.

() Screen line count Usually expressed as the number of white lines or cells per inch or centimeter, for example 175 lines/inch.

() Line ratio or white line width When we say line ratio, taking Figure 1a as an example, we mean the ratio between the width of the white line (m) and the length of one side of the cell (n), and usually the white line width is assumed to be 1. , on the other hand, it is expressed in terms of how large one side of the cell is, for example, 1:3, 1:4, etc. When expressing the width of a white line, the value is expressed as is, for example, 20μ or 30μ.

In the example shown in FIG. 1, the number of lines is different, but the line ratios are all approximately 1:3. In Figure 2, the number of lines is the same, 175 lines/inch, and the line ratio is approximately 1:3 for each of Figures 2a to 2c.
The cases where the ratio is 1:4 and 1:5 are shown.

Of the above, the number of lines (if you take the reciprocal, it becomes pitch),
There is a correlation between the line ratio and the white line width, and if two of these three are determined, the other one is automatically determined, and this relationship is as shown in FIG. 3.
In FIG. 3, the horizontal axis represents the number of screen lines (lines/inch), and the vertical axis represents the screen pitch or width (μ) of the white line. Curve A shows the relationship between the number of screen lines and screen pitch, and curves B, C, and D show the line ratios of 1:2, 1:3, and 1:3, respectively.
It shows the relationship between the number of screen lines and the width of the white line in the case of 1:4.

On the other hand, one of the important characteristics of the screen is the area ratio of the blackened part (opaque part) of the screen. In the case of an orthogonal white line screen in which the cell shape is square, the blackened area area ratio can be calculated using the following simple calculation formula, regardless of the number of lines, once the line ratio is determined.

Now, if we consider an orthogonal white line screen with a line ratio of m:n (see ^{Figure 1} a), the blackened area ratio X of this screen is expressed as follows: It can be calculated by

Most commonly used screens have a line ratio of around 1:3, but when we try to calculate the area ratio of blackened areas for screens with a line ratio around this, we find the following: Become.

The blackened area area ratio of a screen with a line ratio of 1:2 is 44.4% 〃 1:3 〃 56.3% 〃 1:4 〃 64.0% 〃 1:5 〃 69.4% As can be seen from Figure 3, the width of the white line (56.3%) is as follows.

The white line width of a 175 lines/inch screen is: 36.3μ 250 lines/inch 〃 25.4μ 300 lines/inch 〃 21.2μ 400 lines/inch 〃 16.0μ 500 lines/inch 〃 13.0μ 600 lines/inch 〃 10.0μ Above explanation As can be easily understood from the above, when the number of screen lines is the same, as the line ratio increases, the area ratio of the blackened area increases and the width of the white line becomes smaller. As a result, the white line width becomes smaller.

On the other hand, effective means for improving the quality of gravure printed matter include a method of increasing the number of screen lines and a method of increasing the area ratio of blackened areas.

Increasing the number of screen lines means improving the image resolution and producing sharper and smoother printed matter, and increasing the black area ratio means that the cell This leads to an increase in the surface area of the paper, which means that it is possible to obtain printed matter with a more voluminous feel, or in other words, with a richer amount of color.

However, in general, increasing the number of screen lines and increasing the blackened area ratio are accompanied by a decrease in the white line width.

However, there is a limit to reducing the width of the white line. The reason for this is explained as follows.

As you know, gravure printing plates are made by transferring a gravure screen and a carbon tissue with a positive printed onto a copper-plated cylinder, and then using a ferric chloride solution or the like through a gelatin resist obtained by developing this. It is generally obtained by etching. This etching always involves a development called side etching, and the width of the dots on the plate is always narrower than the width of the white lines on the gravure screen. For example, when a gravure printing plate is created using a gravure screen as shown in Fig. 1a to Fig. 1d, the surface condition of the plate is shown in Fig. 4a.
〜As shown in FIG. 4d. In Figure 4 a
From ~c to c, the dots 3 are formed continuously, and the cells 4 are independent, but the dot width is narrower than the white line width of the gravure screen due to side etching. 3, only the part corresponding to the intersection of the white lines remains, and the rest has disappeared. It is no longer possible to carry out gravure printing with a printing plate such as that shown in FIG. 4d.

The characteristics of side etching are represented by an etching factor F, which takes a constant value when certain etching system conditions are determined. Figure 5 is an explanatory diagram of side etching.
The etching factor F when the copper 5 on the gravure cylinder is etched by an etching solution through the resist 6 is determined by the etching depth d and the side etching amount V using the simple formula: F=2d/V (2) expressed.

As is clear from equation (2) above, there exists a relationship in which the side etching amount V is proportional to the etching depth d. FIG. 6 shows an example of the relationship between the etching depth d and the side etching amount V, which varies depending on the etching factor F, or in other words, the etching conditions.

If the dots become too thin due to side etching, the printing durability of the plate will decrease. Some literature states that the ratio of the dot width to the cell side on the plate is limited to about 1:6 to 1:8.

Therefore, under certain etching conditions, it is necessary to use a screen with a white line width that takes into account the thinning of the dots by the amount of side etching estimated from the etching factor.

Here, there is a contradictory conflict between the quality requirement of increasing the number of screen lines and the area ratio of blackened areas, and the technical requirement of not being able to produce a small white line width.

As a result of a compromise between the above-mentioned conflicting demands, the gravure screens currently in use have a line ratio of about 175 lines/inch or 250 lines/inch, and most of them have a line ratio of around 1:3.

In addition, as a special gravure screen, the width of the white line is narrowed to about 17 to 9.3μ, and the number of lines is reduced.
A gravure screen with a line density of about 250 to 500 lines/inch is disclosed in Japanese Utility Model Application No. 1297/1983 or Japanese Patent Application Laid-Open No. 1983-1989.
-Disclosed in Publication No. 155301.

This type of gravure screen has narrow white lines and a large number of lines, so it is expected that the tone reproducibility will be significantly improved. Since this is close to the limit, it is impossible from a practical point of view to increase the number of screen lines any further.

Furthermore, a gravure screen with a screen line count of 300 or 600 lines is disclosed in Japanese Patent Laid-Open No. 14005/1983. However, the screen disclosed in this publication has a blackened area ratio of 40~
It is about 45%, and therefore the amount of color is insufficient during printing, making it impossible to produce the powerful expression that is characteristic of gravure printing.Moreover, the blackened area is a special screen with a round dot shape. Furthermore, in consideration of side etching during etching, it is impossible from a practical standpoint to increase the area ratio of the blackened portion any further.

The present invention is different from the conventional gravure screens described above, and aims to provide a gravure screen that is greatly improved in terms of the number of screen lines and/or the area ratio of blackened areas.

In other words, the present invention can greatly increase the area ratio of blackened areas when the same number of screen lines as before is secured, and conversely, when the area ratio of blackened areas is maintained at the same level as before. It is an object of the present invention to provide a gravure screen that can greatly increase the number of screen lines and also simultaneously increase both the number of screen lines and the area ratio of blackened areas compared to conventional gravure screens. .

In the gravure screen of the present invention which achieves the above objects, the width of the white line in one direction is different from the width of the white line in the other direction.

7, 8, and 9 are enlarged views showing examples of the gravure screen of the present invention, and the widths of the vertical white line 7 and the horizontal white line 8 are different; The white line 8 is thinner than the vertical white line 7.

The gravure screen shown in Figure 7 has a screen line count of 175 for both vertical and horizontal white lines.
line/inch (i.e. pitch is 145μ),
The width of the vertical white line is about 36μ, the line ratio is 1:3, and the width of the horizontal white line is about 10μ. The blackened area ratio of this gravure screen is approximately 70%. Therefore, in the gravure screen of the present invention, the blackened area ratio is greatly improved compared to the blackened area ratio of 56.3% in the conventional gravure screen with a screen line count of 175 lines/inch and a line ratio of 1:3. ing.

Figures 8 and 9 both show the area percentage of blackened areas.
This is an example of a gravure screen of the present invention with a screen size of 56%, and is an enlarged view when the width of the white line in the vertical direction is about 36 μm and the width of the white line in the horizontal direction is about 10 μm.

In this case, the width of the vertical white line is as shown in Figure 1a, with a screen frequency of 175 lines/inch and a line ratio of 1:
The width of the white line is almost the same as that of the conventional gravure screen No. 3. However, in the case of the gravure screen of the present invention shown in FIG. 8, the shape of the cell portion is square and the length of one side is 66μ. Therefore, the pitch of the vertical white line is 102μ
The number of lines is approximately 250 lines/inch, the pitch of the horizontal white lines is 76μ, and the number of lines is approximately 250 lines/inch.
This corresponds to 330 lines/inch. On the other hand, the 9th
In the case of the gravure screen of the present invention shown in the figure, the shape of the cell portion is rectangular, and the length of the long side is 86μ, and the length of the short side is 60μ. Therefore, the pitch of the white lines in both the vertical and horizontal directions is 96 microns, which corresponds to about 265 lines/inch.

Figures 10, 11, and 12 are respectively 7
9 is an enlarged view of the surface of a gravure printing plate created using the gravure screen of the present invention shown in FIGS. 8 and 9. FIG. In the example shown in these figures,
The part corresponding to the thick vertical white line on the gravure screen is sufficiently secured as dote 9 on the gravure printing plate, but the part corresponding to the thin horizontal white line on the gravure screen is secured in the vertical direction on the gravure printing plate. Only the protruding portion 10 remains at the intersection with the dot in the direction, and the other portions have disappeared due to side etching.

When using the gravure screen of the present invention, whether dots are formed in the part corresponding to the thinner white line or disappear by side etching depends on the etching conditions; A corresponding dote must always be secured.

When a gravure printing plate is created using the gravure screen of the present invention, even if the dots corresponding to the thin white lines of the gravure screen are not sufficiently secured, as shown in FIGS. 10 to 12. The protruding portion 10 remains as shown,
The flow of ink is restricted to some extent by the protruding portion 10.

Although it is possible to make a gravure printing plate using a line screen having white lines in only one direction, in this case, the protruding portions 10 formed when using the gravure screen of the present invention will not be produced. Since there is no ink, the ink flows easily, and therefore there are extremely narrow restrictions on the distance between the dots and the direction of the dots relative to the printing direction. However, such plate-making conditions and printing conditions can be adjusted by using the gravure screen of the present invention. significantly alleviated.

In other words, in the case of a line screen that has white lines in only one direction, a doctor blade is used to scrape off excess ink on the printing plate in the direction of the dots formed on the surface of the gravure printing plate in order to suppress the flow of ink as much as possible. Although it is preferable to impose restrictions such as slanting the ink so that it does not coincide with the direction in which it is taken or using a high ink viscosity, the protruding portion 10 can be formed by using the gravure screen of the present invention. The flow of ink is therefore suppressed and the above-mentioned restrictions are thus significantly relaxed. Furthermore, in the case of a straight line screen, it is desirable to narrow the width of the ink receiving area between the dots in order to suppress the flow of ink, but doing so will reduce the amount of ink retained on the gravure plate surface. As a result, the amount of color for printed matter will also be reduced accordingly. By using the gravure screen of the present invention, even if the dots corresponding to the thinner white lines are not sufficiently formed, the ink flow is suppressed by the formation of the protruding portion 10, and therefore the dots are not sufficiently formed. The width of the ink-receiving area between the two can be made wider by that amount than when using a line screen, and it is possible to provide printed matter with a rich amount of color. Furthermore, when the gravure screen of the present invention is used as compared to a line screen, the width of the ink receiving portion between the dots can be made wider, which means that the etching conditions can be eased accordingly. In other words, if we compare the line number and line ratio of the thicker white line in the gravure screen of the present invention to the case where the line number and line ratio of the straight line screen are the same, it is found that the flow of ink is suppressed in the case of the straight line screen. Therefore, it is desirable to control etching so that the width of the ink receiving part between the dowels does not become too wide. However, when using the gravure screen of the present invention, the width of the ink receiving part between the dots The etching conditions can be relaxed by the amount that can be made wider.

As explained above, the gravure screen of the present invention can improve the blackened area ratio while maintaining the same number of screen lines as the conventional gravure screen; The number of screen lines can be increased while maintaining the same blackened area ratio.

Furthermore, according to the gravure screen of the present invention,
The screen frequency is extremely high, which has only been described in the literature but has not been put into practical use, or even if it is put into practical use, it causes a decline in the quality of printed matter due to a decrease in the area ratio of blackened areas. A gravure screen with a large number of lines (for example, 400 lines/inch, 450 lines/inch or more) can be made practical, and it is possible to improve the quality of printed matter without degrading it.

For example, the width of the thicker white line is 15μ and the pitch is 55.2μ.
In the case of an orthogonal screen where the width of the thinner white line is 5μ (line ratio 1:2.7) and the pitch is 55.2μ (line ratio 1:10), the shape of the blackened part of the cell part will be a rectangle. The number of screen lines is 460 lines/inch for both the thicker white line and the thinner white line, and the blackened area ratio is 66.2%.

As another example, set the width of the thicker white line to 15μ,
In the case of an orthogonal screen where the pitch is 55.2μ (line ratio 1:2.7), the width of the thinner white line is 5μ, and the pitch is 79.4μ (line ratio 1:14.9), the shape of the blackened part of the cell part is rectangular. In this case, the screen line count is 460 lines/inch for the thicker white line and 460 lines/inch for the thinner white line.
320 lines/inch, and the area ratio of the blackened area is 68.2%.

The width of the thicker white line of these screens is 15μ
However, if side etching is taken into account when creating a gravure printing plate, the white line width is close to the limit.
Maintaining this kind of white line width and increasing the number of screen lines
There has never been a gravure screen that has been put into practical use that has a line ratio of 460 lines/inch or more and a blackened area ratio of 66% or more.

Furthermore, as another example of an orthogonal screen where the width of the thicker white line is 15μ and the width of the thinner white line is 5μ, if the line ratio of the thicker white line is 1:1.5, the screen line count is 677 lines/inch. And if the line ratio of the thinner white line is 1:15, the number of screen lines is
318 lines/inch, and the area ratio of blackened areas is
It becomes 56.3%. This is a gravure screen that has an extremely large number of screen lines while maintaining the blackened area ratio of the conventionally widely used gravure screen, and is also practical.

The amount of side etching varies depending on the etching conditions as described above, but if we assume that the width of the white line is reduced by 5μ due to side etching, then the width of the thicker white line is 15μ and the number of lines is 677 lines/inch and the thinner. When using a gravure screen with a white line width of 5μ on the side and a number of lines of 318 lines/inch, the blackened area ratio of the screen is 56.3%, but after etching, it corresponds to the thinner white line by side etching. No dotes are formed and the cell area ratio is 73.3%. On the other hand, when using a conventionally widely used gravure screen with 175 lines/inch both vertically and horizontally, a white line width of 36.3μ, and a blackened area ratio of 56.3%, the dot width decreases due to side etching. Even if the etching value is 5μ, the cell area ratio after etching is only 61.2%.

The gravure screen of the present invention can be used practically with a very large number of screen lines, so even if it has the same blackened area ratio as a conventional gravure screen, it can be used even after etching. The cell area ratio of the gravure printing plate can be made much larger than that of conventional gravure screens.

Therefore, for example, in the gravure screen of the present invention, the width of the thicker white line is 15 μ and the number of screen lines is
In the case of an orthogonal screen with 1000 lines/inch (line ratio 1:0.69), the width of the thinner white line is 5μ, and the screen line count is 318 lines/inch (line ratio 1:15), the blackened part of the screen The area ratio is 38.3%, but if the side etching amount is 5μ, the area ratio of the cells of the gravure printing plate after etching is approximately 60.6%, which is 61.2% after etching of the conventionally widely used gravure screen. It is almost close to %.

In the gravure screen of the present invention as explained above, the width of the white line in one direction is different from the width of the white line in the other direction, and therefore the number of screen lines and/or the area ratio of the blackened area of the gravure screen can be dramatically increased. increase can be achieved. In this case, the difference in width between the thicker white line and the thinner white line can be set arbitrarily as needed, and the width of the thicker white line can be set on the gravure printing plate after etching. As long as the width is set so that the dote is sufficiently formed, the width of the narrower white line should be less than that.
If the width of the thicker white line is assumed to be L, then the width of the thinner white line is preferably about 0.33L or less. If the width of the thinner white line is thicker than 0.5L, the difference from the conventional gravure screen will not be as noticeable. The width of the ink receiving area between the dots corresponding to the thicker white line of the gravure screen on the gravure printing plate after etching is 25μ
It is preferable to keep it above this level; if it is below this level, ink transfer from the gravure printing plate to the printing material will not be good. Since the width of the ink receiving area between the dots varies depending on the amount of side etching, the width of the cell portion of the gravure screen can be determined by taking the etching conditions into consideration. In addition, it is desirable that the pitch of the thinner white line on the gravure screen be approximately 500μ or less.
When the thickness exceeds 1000μ, it becomes difficult to prevent ink from flowing.

As explained above, in the gravure screen of the present invention, the white line in one direction is thinner than the white line in the other direction, and the screen line number of the thicker white line is 175.
In the case of about 250 lines/inch, the number of screen lines is about the same as that of conventional gravure screens commonly used, but the area ratio of blackened areas can be dramatically improved.

In addition, gravure screens with a screen line count of about 300 to 400 lines/inch have been used infrequently, but at the cost of deteriorating the quality of printed matter due to a decrease in the area ratio of blackened areas. However, the gravure screen of the present invention does not suffer from the above-mentioned deterioration in quality even if the screen line count of the thicker white line is 300 to 400 lines/inch.

Furthermore, gravure screens with a screen line count of about 450 to 600 lines/inch have rarely been put into practical use, or even if they are put into practical use, the drop in print density is significant, so they can only be produced in small quantities in very special cases. Although it was only used for printing,
The gravure screen of the present invention does not cause the above-mentioned decrease in density even when the screen frequency of the thicker white line is about 450 to 600 lines/inch, and it is different from the gravure screen commonly used in the past. It is possible to maintain a print density similar to that of the conventional gravure screen, and to obtain a printed matter with better resolution than the gravure screen that has been widely used in the past.

Furthermore, it is difficult for gravure screens with a screen line count of about 600 lines/inch or more to satisfy the conditions of maintaining sufficient printing density, resisting side etching, and forming sufficient dots on the printing plate. However, according to the gravure screen of the present invention, it has become possible to put it into practical use with a screen of 600 lines/inch or more, and it is possible to expand the practical range to about 1000 lines/inch. .

With the gravure screen of the present invention as described above, it is possible to increase the number of screen lines and/or the area ratio of blackened areas, so it is possible to obtain excellent printed matter. Since it is thinner than the white line in the direction, excellent printed matter can be obtained for the following reason.

That is, when the gravure screen of the present invention is used, on the gravure printing plate, almost no dots are formed on the gravure printing plate, or even if they are formed, the dots are extremely thin, so that the dots are not formed in the image area. The boundary between the image and the non-image area is reproduced smoothly.

FIG. 13 and FIG. 14 are partially enlarged views of the boundary between the image area 11 and the non-image area 12 in printed matter when a conventional gravure screen is used and the gravure screen of the present invention is used, respectively. . When a conventional gravure screen is used, as is clear from FIG. 13, there are noticeable areas in both the vertical and horizontal directions where the ink does not adhere to the printing material due to the influence of doping. On the other hand, when the gravure screen of the present invention is used, as is clear from FIG. 14, the part where the ink does not adhere to the printing substrate due to the influence of doping is the part corresponding to the thicker white line. Most of the damage is due to the dote (vertical dote), and the dote in the part corresponding to the thinner white line is hardly formed, or even if it is formed, it is very thin, so this dote has little effect. None, or very few if any.

Therefore, according to the gravure screen of the present invention, printed matter with excellent image reproducibility can be obtained. Furthermore, when the gravure screen of the present invention is used in a method of making a gravure printing plate in combination with a halftone positive for planography or letterpress printing, it has the following advantages in addition to the advantages obtained when used in the conventional gravure method. The effects as described can also be obtained.

When a gravure printing plate is created by combining the fine positive for planography or letterpress with a gravure screen, the halftone dots of the halftone positive will have portions cut by the dots of the gravure screen. In particular, there was a problem in that the reproducibility of minute halftone dots in the light area was poor. However, when the gravure screen of the present invention is used, the influence of dots is halved as described above, so the reproducibility of minute halftone dots in the light area is significantly improved.

Furthermore, when a net positive for planography or letterpress printing is combined with a gravure screen, a moiré pattern is likely to occur between the net positive and the gravure screen. Therefore, when a conventional gravure screen is used, the range for adjusting the relative angle between the screen angle of the net positive and the screen angle of the gravure screen is very narrow so that the moire pattern becomes less noticeable. Therefore, accurate workability was required. However, according to the gravure screen of the present invention, the number of screen lines of the thicker white line can be made very large, and the larger the number of screen lines of the gravure screen, the less noticeable the moire pattern is. Adjustment of the screen angle between the net positive and the gravure screen becomes easy.

This screen angle adjustment work depends on the number of screen lines of the positive screen used.
When the number of screen lines of the net positive is about 150 lines/inch, the effect starts to become noticeable when the screen line number of the thicker white line of the gravure screen of the present invention is 300 lines/inch or more, and when the screen line number of the gravure screen of the present invention is 300 lines/inch or more, the effect becomes noticeable. This is especially noticeable in the above cases.

Regarding the gravure screen of the present invention, so far we have explained the case of an orthogonal screen, but as a conventional gravure screen, the 15th
As shown in FIG. 1 and FIG. 16, brick screens, diagonal screens, and the like are also known, and the gravure screen of the present invention may have such a pattern. FIGS. 17 and 18 show one embodiment of the gravure screen of the present invention, which corresponds to FIGS. 15 and 16, respectively.

[Brief explanation of drawings]

Figures 1 and 2 are explanatory diagrams of various examples of conventional gravure screens, Figure 3 is a graph of the relationship between the number of screen lines and the width of the white line or the number of screen lines and screen pitch, and Figure 4 is a graph of the relationship between the number of screen lines and the width of the white line or the number of screen lines and screen pitch. An explanatory diagram of a gravure printing plate after etching when using the gravure screen shown in the figure, FIG. 5 is an explanatory diagram of side etching, FIG. 6 is a graph of the relationship between etching depth and side etching amount, and FIGS. FIG. 9 is an explanatory diagram of an embodiment of the gravure screen of the present invention, the first
Figures 0 to 12 are illustrations of gravure printing plates after etching using the gravure screens shown in Figures 7 to 9, and Figures 13 and 14 are illustrations of gravure printing plates using conventional gravure screens, respectively. FIGS. 15 and 16 are explanatory diagrams of the boundary between image and non-image areas in printed matter when the gravure screen of the present invention is used; FIG. 17 is another explanatory diagram of the conventional gravure screen; FIG. , Figure 18 is the first
FIG. 5 shows explanatory diagrams of embodiments of the gravure screen of the present invention corresponding to FIG. 16, respectively. 1... Opaque part, 2... Transparent line segment, 3... Dote, 4... Cell, 5... Copper, 6... Resist, 7
...Vertical white line, 8...Horizontal white line, 9...
Dote, 10... Protruding portion, 11... Image portion, 1
2...Non-image area.

Claims (1)

[Claims] 1. In gravure screens having transparent or opaque line segment patterns such as orthogonal screens, oblique screens, brick stacked screens, etc., the width of the line segment in one direction of the line segment pattern is the width of the line segment in the other direction. The width of the line segment that is narrower and thicker is 9μm.
A gravure screen having the above structure, and having a screen line count of 175 lines/inch or more and a blackened area ratio of 56% or more.