JP2005026987A - Printing dot, printing plate, and printing dot formation method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To increase the concentration of the medium tone of printing without losing the conventional printing stability in cluster dots, and to decrease the amount of ink. <P>SOLUTION: In printing dots used for printing, a basic unit for composing dots or the minimum unit has a hollow structure. Additionally, a printing plate and printed matter have the halftone dots. As the example of the hollow structure, there are a multiple hollow structure, a hollow structure having a plurality of different shapes, a hollow structure whose shape is different according to an area rate, a hollow structure where the sequencing of dots to be formed by the distance from the center is performed, a hollow structure having a shape whose periphery length is maximized, and the like. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a technique for forming halftone dots used for printing.
[0002]
[Prior art]
The gradation of printing is expressed by the size or density of dots called halftone dots. There are various types of halftone dots, but as shown in FIG. 1, a cluster type (see, for example, Patent Literature 1 and Patent Literature 2) and a dot dispersion type, which are referred to as a periodic type, an aperiodic type, and a dot concentration type. It can be roughly divided into a disperse type (for example, refer to Patent Document 3).
[0003]
[Patent Document 1]
Japanese Patent Laid-Open No. 9-200518 [Patent Document 2]
JP 2001-186346 A [Patent Document 3]
JP-A-7-85272 [0004]
A halftone dot of a printing plate that is widely used at present is digitally formed by turning on / off a laser spot of about 10 microns. The cluster type halftone dot is formed by a halftone dot matrix having a basic unit of about 10 × 10 to 20 × 20 spots, and the disperse type halftone dot is a small dot having a uniform size (usually a small dot). A dot is formed with the size of the dot as a basic unit.
[0005]
Each halftone dot is known to have the characteristics shown in FIG. The disperse halftone dot has a large amount of boundary line between the ink and the paper, has a large light scattering effect inside the paper as shown in FIG. 3C, and the ink around the halftone dot as shown in FIG. Since the colored light oozes out and the density of the halftone increases, there is an ink reduction effect in a printed matter having a halftone.
[0006]
However, since the dispersive halftone dots require accurate small dot reproduction in order to reproduce the gradation, there is a problem that printing stability is poor due to the small halftone dots as described above.
[0007]
On the other hand, a widely used cluster type halftone dot has a large halftone dot, and therefore there is a problem that the amount of ink cannot be reduced due to an improvement in halftone density, unlike the disperse type.
[0008]
In addition, in the periodic cluster type halftone dot (normal AM screening), there is also a problem that moire tends to occur due to interference with the period of the image.
[0009]
[Problems to be solved by the invention]
The present invention has been made in view of the above-mentioned problems, and its purpose is to increase the density of halftone printing and reduce the amount of ink in a cluster type halftone dot without impairing the conventional printing stability. It is to be.
[0010]
[Means for Solving the Problems]
In order to solve the above-described problems, according to a first aspect of the present invention, a hollow structure is provided in a basic unit or a minimum unit constituting a halftone dot in a print halftone dot used for printing.
[0011]
According to a second aspect of the present invention, in the printing halftone dot according to the first aspect described above, multiple hollow structures are provided in the basic unit or the minimum unit constituting the halftone dot.
[0012]
According to a third aspect of the present invention, in the printing halftone dot according to the first or second aspect described above, a plurality of differently shaped hollow structures are provided in the basic unit or the minimum unit constituting the halftone dot.
[0013]
According to a fourth aspect of the present invention, a printing plate having a halftone dot used for printing is provided with a printing halftone dot whose basic unit or minimum unit has a hollow structure.
[0014]
According to a fifth aspect of the present invention, in the printing plate according to the fourth aspect described above, a printing halftone dot having a hollow structure in which the basic unit or the minimum unit constituting the halftone dot is multiplexed is provided.
[0015]
According to a sixth aspect of the present invention, in the printing plate according to the fourth or fifth aspect described above, a halftone dot is provided with a printing halftone dot having a hollow structure having a plurality of different basic units or minimum units. It is.
[0016]
According to a seventh aspect of the present invention, in the printing plates according to the fourth to sixth aspects described above, different hollow dot shapes are provided according to the area ratio.
[0017]
According to an eighth aspect of the present invention, in a printed matter printed with a printing plate having a halftone dot, the basic unit or the minimum unit is printed with a printing plate having a printing halftone having a hollow structure.
[0018]
According to a ninth aspect of the present invention, in the printed matter according to the eighth aspect described above, the basic unit or the minimum unit constituting the halftone dot is printed by a printing plate provided with a printing halftone having a multiple hollow structure. It is a thing.
[0019]
According to a tenth aspect of the present invention, in the printed matter according to the eighth or ninth aspect described above, a printing plate comprising a printing halftone dot having a hollow structure having a plurality of differently shaped basic units or minimum units constituting the halftone dot. It is intended to be printed.
[0020]
According to an eleventh aspect of the present invention, in the printed matter according to the above eighth to tenth aspects, printing is performed by a printing plate having a printing halftone dot having a hollow halftone dot shape that varies depending on the area ratio. is there.
[0021]
According to a twelfth aspect of the present invention, in the method for forming a halftone dot used in a printing plate, a step of preparing a halftone dot matrix in which dots formed by distance from a center in advance are prepared; And a step of comparing the matrix and the multi-tone image data to form a halftone dot shape having a hollow structure.
[0022]
According to a thirteenth aspect of the present invention, in the halftone dot forming method according to the twelfth aspect described above, a step of preparing a plurality of types of halftone matrix according to the area ratio, and an area ratio from the plurality of types of halftone dot matrix A step of selecting one in accordance with the step and a step of comparing the selected halftone dot matrix with the multi-tone image data so as to form a halftone dot shape having a different hollow structure in accordance with the area ratio. Is.
[0023]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, the present invention will be described based on the illustrated embodiments. FIG. 5 schematically shows a procedure for forming a hollow dot shape according to the present invention.
[0024]
First, the dots formed by the distance from the center are ranked, and a halftone dot matrix that forms a hollow structure at the center is prepared. It is also possible to evaluate and adjust in advance so that the perimeter is maximized.
[0025]
Next, the multi-tone image data is divided into several regions, and attention is paid to the specific region (the region surrounded by a thick frame in FIG. 5). A halftone dot having a structure is formed.
[0026]
Conventionally, a halftone dot matrix is designed so as to form dots evenly from the center, and the procedure for forming halftone dots is the same as shown in FIG. 6, but the shape of the halftone dots to be formed is different.
[0027]
FIG. 7 is an example of gradation expression by the hollow halftone dot of the present invention. In FIG. 7, as in the prior art, the halftone dot angle is changed for each plate in order to eliminate the same angle moire for each color plate.
[0028]
Although described with reference to the embodiment of the present invention, the present invention maximizes the light scattering effect by increasing the length of the boundary between the halftone dot and the paper while ensuring the conventional printing stability. It is characterized in that the printing density is increased by use, and is not limited to the shape of a halftone dot, the shape of a hollow structure, or the number of hollow structures.
[0029]
For example, the halftone dots in FIG. 7 are designed such that the image line portion in the highlight region has a donut shape in the shadow region, but depending on the area ratio, It is also possible to make a donut shape only in the middle part.
[0030]
This is formed by preparing a plurality of halftone dot matrices corresponding to the area ratio, selecting a halftone dot matrix to be used for comparison by the area ratio, and comparing with a multi-tone image as in the procedure shown in FIG. be able to. An example of a partial hollow halftone dot structure by area ratio is shown in FIG.
[0031]
Further, the halftone dot shape having a hollow structure is not limited to the donut-shaped shape or circle of FIGS. 7 and 9, and may be a hollow structure of any shape as shown in FIGS.
[0032]
Also, the number of hollow structures is not limited to one, and a plurality of hollow structures are stacked to form a multiple structure as shown in FIG. 11 (a), or a plurality of hollow structures are provided as shown in FIG. 11 (b). As a result, the boundary line between the halftone dots and the paper can be made longer and the print density can be increased more at the same area ratio.
[0033]
It can also be applied to a disposable halftone dot. For example, when forming a 21-micron minimum dot with a 7-micron laser spot, the center spot may be removed when forming a 3 × 3 spot.
[0034]
【The invention's effect】
As described above, according to the printing halftone dot, printing plate, and halftone dot forming method according to the present invention, a halftone dot having a hollow structure is formed, the length of the boundary line between the halftone dot and the paper is increased, and light scattering is performed. By increasing the ink color oozing area due to the effect, the printing density can be increased and the amount of ink used can be reduced.
[0035]
Since the halftone dot of the smallest unit is larger than that of the disperse type halftone dot, printing stability can be ensured.
[Brief description of the drawings]
FIG. 1 is an explanatory diagram of types of halftone dots.
FIG. 2 is an explanatory diagram of quality characteristics of each halftone dot.
FIG. 3 is an explanatory diagram showing how light is scattered inside paper.
FIG. 4 is an explanatory diagram of an ink color bleeding region due to light scattering.
FIG. 5 is a schematic diagram showing a halftone dot forming procedure according to the present invention.
FIG. 6 is a schematic diagram showing a conventional halftone dot forming procedure.
FIG. 7 is a reproduction example of gradation according to the present invention.
FIG. 8 is a schematic diagram showing a procedure for forming halftone dots having different hollow structures depending on the area ratio of the present invention.
FIG. 9 is an example in which halftone dots having different hollow structures are formed according to the area ratio of the present invention.
FIG. 10 is an example of a halftone dot other than a donut shape according to the present invention.
FIG. 11 is an example of multiple hollow structures and multiple hollow structures of the present invention.

Claims (13)

Printing dot used for printing,
A printing halftone dot characterized in that the basic unit or minimum unit constituting the halftone dot has a hollow structure. The printing halftone dot according to claim 1,
A printing halftone dot characterized in that the basic unit or minimum unit constituting the halftone dot has a multiple hollow structure. A printing dot according to claim 1 or 2,
A printing halftone dot characterized in that a basic unit or minimum unit constituting a halftone dot has a plurality of differently shaped hollow structures. A printing plate having a halftone dot used for printing,
A printing plate comprising a printing halftone dot in which a basic unit or a minimum unit has a hollow structure. The printing plate according to claim 4, wherein
A printing plate comprising a printing halftone dot having a hollow structure in which the basic unit or minimum unit constituting the halftone dot is a multiple. The printing plate according to claim 4 or 5, wherein
A printing plate comprising a printing halftone dot having a plurality of differently shaped hollow structures in which the basic unit or the minimum unit constituting the halftone dot is a plurality. The printing plate according to any one of claims 4 to 6,
A printing plate having a hollow halftone dot shape depending on an area ratio. A printed matter printed by a printing plate having a halftone dot,
A printed matter, wherein a basic unit or a minimum unit is printed by a printing plate having a printing halftone dot having a hollow structure. The printed matter according to claim 8,
A printed matter comprising a printing plate having a printing halftone dot in which a basic unit or minimum unit constituting a halftone dot has a multiple hollow structure. The printed matter according to claim 8 or 9,
A printed matter, wherein a basic unit or a minimum unit constituting a halftone dot is printed by a printing plate having a printing halftone dot having a plurality of differently shaped hollow structures. A printed matter according to any one of claims 8 to 10,
A printed matter comprising a printing plate provided with a printing halftone dot having a different hollow halftone dot shape depending on an area ratio. A method for forming halftone dots for use in a printing plate,
Preparing a halftone dot matrix in which dots formed by the distance from the center are ranked in advance;
Comparing the halftone dot matrix with multi-tone image data,
A halftone dot forming method comprising forming a halftone dot shape having a hollow structure. A halftone dot forming method according to claim 12,
Preparing a plurality of types of halftone dot matrix according to the area ratio;
Selecting one according to the area ratio from the plurality of types of halftone dot matrices;
And a step of comparing the selected halftone dot matrix with the multi-tone image data, and forming a halftone dot shape having a different hollow structure in accordance with the area ratio.

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