JP5050319B2 - chart - Google Patents

Description

  The present invention relates to a chart in which the relationship between a solid density and a flat screen density can be easily grasped in order to study the standard solid density of each ink in offset printing using process ink.

  In offset printing, process inks of four colors of black, cyan, magenta, and yellow are often used, and as a first target for managing these inks in printing, a predetermined solid density is used or calibration is performed. It has been practiced to use the density of the printed print scale. (For example, see Patent Document 1.)

In the former, in order to examine the standard solid density for each ink, a plurality of combinations of solid density and 75% flat halftone density, or a combination of solid density and 80% flat halftone density are collected, and the K value obtained therefrom. In many cases, the print standard solid density is examined with reference to the relationship between the% contrast and the solid density, which is referred to as “a”.
The formula for calculating the K value is as follows.
K = ((Ds−Dt) / Ds) × 100
Ds: solid density Dt: 75% or 80% flat mesh density

Conventionally, in order to grasp the relationship between the K value and the solid density, a plurality of sheets are printed by changing the amount of ink discharged during printing, and a desired sample is taken out and measured after printing, or the target solid density is determined. A method was adopted in which a plurality of settings were made and a printed material suitable for them was created.
In the former case, it is necessary to measure the solid density of many printed materials in order to extract a desired sample. In the latter case, it takes a lot of time and printing paper to create a printed material that matches the target solid density, and it takes time to obtain the K value.

Japanese Utility Model Publication No. 5-39889 (prior art)

  The problem to be solved by the present invention is that, in offset printing using process inks of black, cyan, magenta, and yellow, in order to study the standard solid density for each ink, the solid density and the 75% flat mesh When collecting a plurality of combinations of density or solid density and 80% flat screen density and referring to the relationship between% contrast and solid density called K value obtained from them, one sheet is used for examining the standard solid density of printing. A chart that allows you to collect multiple patterns of solid density and 75% flat screen density or a combination of solid density and 80% flat screen density for each ink and easily grasp the relationship between K value and solid density for each ink. Is to provide.

Accordingly, one of the present invention for solving such problems is a color density measurement patch region including a solid and at least one flat mesh provided for each ink color used for offset printing, and At least a pattern region including a plurality of regions having different pattern amounts accumulated in the printing direction in accordance with each ink key, and the pattern region includes black, cyan, magenta, and yellow. Of the four colors, 2 are 15% and the remaining 2 are 50% of the pattern area ratio. The pattern is gradually changed from right to left when the printing direction is set up and down according to each ink key of the printing press. The printing area comprises a region 1 (pattern pattern (a)) in which the area ratio is low, a pattern area ratio of 2%, which is 15% in the area 1, 50%, and two colors, which are 50% in the area 1, 15%. Each ink key Together, the printing direction vertically and slowly picture pattern area rate from left to right if is lower region 2 (picture pattern (b)), a chart, comprising the.
By varying the amount of the image accumulated in the printing direction in this way, it is possible to change the ink consumption on the paper surface, and as a result, the measurement patch has a density change corresponding to the amount of the image varied. It becomes possible to make it.
The reason why the lower limit of 15% is set is that when the pattern area ratio is less than this, overemulsification is likely to occur, and accurate% contrast cannot be evaluated. The upper limit of 50% is used in normal printing. This is because the upper limit of the integration of the pattern area ratio is about this level, so that the relationship between the solid density and the flat screen density under normal printing conditions can be obtained.

  The flat net is a chart of 75% or 80% flat net.

Moreover, it is the chart which provided the slur gauge.
By providing a slur gauge, it is possible to determine whether this chart has been printed properly without slurs or duplication.

  According to the present invention, when examining the printing standard solid density, it is possible to collect a plurality of combinations of solid density and plain halftone density for each ink from one printed matter, and the relationship between K value and solid density is simple. Can grasp.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

  FIG. 1 is a schematic diagram showing an example of the configuration of a print standard density study chart according to an embodiment of the present invention.

  First, the color density measurement patch region 100 includes, for example, a black 75% patch 1 and a black solid patch 3 as a combination of solid density of black ink and 75% flat halftone density or a combination of solid density and 80% flat halftone density. Black 80% patch 5 can be obtained. These three patch combinations are arranged side by side in accordance with the ink keys of the printing press.

  For other cyan, magenta, and yellow, the same three types of patches as black are arranged on the left and right in accordance with each ink key.

  Next, the pattern area 200 is composed of a pattern pattern (a) 25 and a pattern pattern (b) 27 as an example.

  The pattern pattern (a) 25 is a combination of 50% black, 15% cyan, 50% magenta, and 15% yellow so that the area ratio gradually decreases from right to left in accordance with each ink key of the printing press. It is configured. The role of the pattern (a) is to consume black and magenta inks. Cyan and yellow are not 0 but 15% in order to prevent over-emulsification of the ink.

  At the time of printing, the ink key opening of the printing press is made constant. As the ink is consumed in the pattern (a) 25, the black solid density on the right side of the paper becomes low and the black solid density on the left side becomes high. By measuring the black solid patch 3 on the right end and the black solid patch 3 on the left side, the range of the solid density that can be investigated is known. When the minimum solid density is too low or the maximum solid density is too high, the investigation range can be adjusted by the rotation speed of the ink source roller of the printing press or the opening and closing of the entire ink key.

  The pattern pattern (b) 27 is obtained by multiplying black 15%, cyan 50%, magenta 15%, and yellow 50% so that the area ratio gradually decreases from left to right in accordance with each ink key of the printing press. It is configured. The role of the pattern (b) is to consume cyan and yellow ink. Black and magenta are set to 15% instead of 0 to prevent excessive emulsification of the ink.

  The method of changing the percentage of each color and the area ratio may be arbitrarily designed within a range not departing from the present invention, depending on the solid density range to be investigated.

  In this example, the relationship between the K value and the solid density was investigated using the chart having the configuration shown in FIG.

Before starting printing, it was investigated whether the opening setting value of each ink key was the same as the actual opening.
In the printing press used in the present embodiment, the above relationship is aligned. However, when the relationship is not aligned, the adjusted range can accurately grasp the investigation range of the solid density range, so that the accuracy of the investigation is improved.

  When printing was performed with the opening of each ink key being constant, the density of the black solid patch 3 at the right end was 0.8. Since the solid density range of 1.0 to 2.0 was planned to be investigated, the opening of the entire ink key was increased.

  As a result of the above operation, the density of the black solid patch 3 at the right end became 1.02. The density of the black solid patch 3 at the left end of the printed material was 1.79. Since the solid density range of 1.0 to 2.0 was planned to be investigated, the opening of the entire ink key was increased.

As a result of the above operation, the density of the black solid patch 3 at the left end became 2.02.
Similar ink key opening adjustments were made for cyan, magenta, and yellow.

  From the above test printing, a print sample was obtained in which only two sheets of black, cyan, magenta, and yellow were able to grasp the relationship between the K value and the solid density in the solid density range of 1.0 to 2.0.

  In this embodiment, a 75% flat halftone density is used for the calculation of the K value, and the black 75% patch 1, the black solid patch 3, the cyan 75% patch 7, the cyan solid patch 9, Magenta 75% patch 13 / magenta solid patch 15 and yellow 75% patch 19 / yellow solid patch 21 were measured with a densitometer. FIG. 2 shows the K value calculated from the obtained density value and plotted against each solid density.

  As can be seen from FIG. 2, the K value = contrast value (%) increases as the solid density increases, reaches a peak at a certain point, and then decreases. The approximate solid densities at the peak are black 1.8, cyan 1.85, magenta 1.65, and yellow 1.5. To determine the standard density, there are items to be examined in addition to the relationship between the K value and the solid density. However, when the solid density is higher than the above, the contrast of the printed matter is lowered.

  According to the printing standard density examination chart of the present invention, in offset printing using process inks of black, cyan, magenta, and yellow, solid density and 75% flat mesh density for each ink from one printed matter. Alternatively, it is possible to collect a plurality of patterns of combinations of solid density and 80% flat mesh density, so that the relationship between K value and solid density can be easily grasped.

  The present invention can be used for examination of the standard solid density of each ink in offset printing using process ink.

It is a figure which shows an example of the structure of the chart concerning embodiment of this invention. It is a graph showing the relationship between K value = contrast value (%) and solid density in the Example of this invention.

Explanation of symbols

1 ... Black 75% patch 3 ... Black solid patch 5 ... Black 80% patch 7 ... Cyan 75% patch 9 ... Cyan solid patch 11 ... Cyan 80% patch 13 ... Magenta 75% patch 15 ... Magenta solid patch 17 ... Magenta 80% patch 19 ... Yellow 75% patch 21 ... Yellow solid patch 23 ... Yellow 80% patch 25 ... Picture pattern (a )
27 ... Pattern (b)
29 ... Slur gauge 31 ... Control strip 100 ... Color density measurement patch area 200 ... Picture area

Claims (3)

A patch area for color density measurement including a solid and at least one flat net provided for each ink color used for offset printing;
A pattern area comprising a plurality of areas that are composed of all inks and have different pattern amounts integrated in the printing direction according to each ink key;
Having at least
The pattern area is
Of the four colors of black, cyan, magenta, and yellow, two colors are 15% and the remaining two colors are 50% of the pattern area ratio, and the printing direction is set to the vertical direction according to each ink key of the printing press. Region 1 (pattern pattern (a)) in which the pattern area ratio gradually decreases from right to left,
When the printing area is set to the up and down direction according to each ink key of the printing machine, the two areas of 15% in area 1 are 50%, and the two colors of 50% in area 1 are 15%. Region 2 (pattern pattern (b)) in which the pattern area ratio gradually decreases from left to right;
A chart characterized by comprising:   The chart according to claim 1, wherein the flat net is a 75% or 80% flat net.   A chart comprising a slur gauge provided on the chart according to claim 1.