JP2010217007A - Apparatus and method for evaluating toughness of printed matter - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for evaluating the toughness of a printed matter, capable of evaluating initial-stage toughness even for a printed matter formed using an inkjet device and ink, and relatively easily acquiring data in a short time. <P>SOLUTION: The method for evaluating the toughness of a printed matter in which images or characters are formed on a printed medium using an inkjet device and ink includes: using the same printed medium as the printed matter to be evaluated as a test piece on which no image or character is formed to bring the test piece into contact with a printed surface of the printed matter; rubbing the test piece with a uniform load being placed thereon by a predetermined number of times to thereby measure the change quantity of optical density of the rubbed surface of the test piece and the change quantity of glossiness of the rubbed surface of the printed matter; and mutually comparing the measurement values and evaluation values calculated from the measurement values with predetermined optional reference values to thereby evaluate the toughness. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a method for evaluating fastness such as scratching and durability of printed matter and a device for evaluating fastness of printed matter.

  As a method for evaluating fastness such as scratching and durability of printed matter, a method of rubbing the printed surface and visually observing the friction surface is often used. For example, JIS K5701 “6.2.3 Friction resistance” stipulates an example of the printing surface friction method, and after conducting friction based on this, the inspector senses the change in the friction surface of the printed material. The method of evaluation and quantification is common.

  However, in such a sensual method, the evaluation standard is not constant, and there are many cases where the objectivity and reproducibility of measurement data are difficult. In addition, visual judgment is considered to be able to evaluate scratchability relatively easily, but in many cases, much labor is required in order to unify test conditions and to obtain accurate data.

  In order to improve this, Patent Document 1 discloses that a printing surface and a printing paper before printing are rubbed by using a wear tester having a mechanism for changing a friction load and a mechanism for detecting a frictional force. Methods for evaluating robustness have been proposed.

JP 2006-125957 A (paragraph numbers [0005], [0006])

  However, the following problems may occur in the prior art described above.

  That is, in the method proposed in Patent Document 1, the relationship between the number of frictions and the frictional force is measured in order to evaluate the robustness, but the actual image changes before the change in the frictional force is detected. May occur.

  That is, there is a case where a difference in fastness at an extremely early stage cannot be detected, and the tendency is particularly remarkable for a printed matter formed using an ink jet device and an ink.

  In addition, the fluctuation of the frictional force is detected after image degradation has progressed to some extent, and it may take a very long time to acquire data.

  Accordingly, an object of the present invention is to provide an evaluation method for printed matter robustness which can evaluate the initial fastness of a printed matter formed using an inkjet device and an ink, and can acquire data relatively easily and in a short time. Is to provide.

  As a result of diligent study, the inventors of the present invention have made a thorough examination, and as a result, a printed matter fastness evaluation apparatus and a printed matter robustness evaluation method are as follows. As a method, it has been found that it has excellent performance with respect to the problems, and has reached the present invention.

That is, a robustness evaluation apparatus for printed matter in which images and characters are formed using an inkjet device and ink on a printing medium,
Using the same printing medium as the printed matter to be evaluated, on which no images or characters are formed, as a test piece, bringing the test piece into contact with the printed surface of the printed matter,
Measure the amount of change in the optical density of the friction surface of the test piece and the change in glossiness of the friction surface of the printed matter by rubbing the test piece a predetermined number of times with a uniform load applied,
It is to provide a robustness evaluation apparatus for printed matter characterized by evaluating fastness by comparing the measured value and an evaluation value calculated from the measured value with a predetermined arbitrary reference value. ,
A method for evaluating the robustness of a printed material on which an image or a character is formed using an inkjet device and ink on a printing medium, wherein the image or character is not formed; Using the same printing medium as a test piece, the test piece is brought into contact with the printed surface of the printed matter, and the test piece is rubbed a predetermined number of times with a uniform load applied thereto. Measure the amount of change in density and the amount of change in gloss on the friction surface of the printed material, and evaluate the robustness by comparing the measured value and the evaluation value calculated from the measured value with a predetermined reference value. The above-mentioned problem can be solved by providing a method for evaluating the robustness of printed matter characterized by the above.

  The reason why the present invention has such excellent performance is not clear, but the present inventors speculate as follows.

  The sensitivity for measuring optical density is extremely higher than the sensitivity for visually detecting image changes and the sensitivity of the frictional force detection mechanism. As a result of the study, the inventors of the present invention, in particular, show that the change in the optical density of the friction surface of the test piece when the printed material is rubbed with the print medium as the test piece is the most sensitive change in the print surface due to friction, that is, the fastness. It was found that can be detected.

  In addition, this tendency is particularly remarkable on the surface of printed matter on which images and characters are formed using an ink jet device and ink.

  In addition, the present inventors have found that the glossiness of the printed surface before and after rubbing may have a strong correlation with the fastness.

  Many conventional methods for evaluating robustness pay attention only to changes due to friction in an image or text itself, in other words, a portion where ink (coloring material) is present.

  However, the present inventors can evaluate the robustness more accurately by evaluating the change caused by the friction including the printing medium, particularly for the printed matter formed using the ink jet device and the ink. I got the knowledge.

  Therefore, as a method for comprehensively and easily quantifying changes due to friction including the printing medium, the inventors have come to the idea of measuring the glossiness of the printed surface after friction.

  Therefore, as described above, by measuring the optical density of the test piece when the printed material is rubbed with the printing medium and the glossiness of the surface of the printed material after friction, the printed material formed using the ink jet device and the ink is also used. It is possible to provide a printed matter fastness evaluation method capable of evaluating initial fastness and capable of acquiring data relatively easily and in a short time.

It is a schematic diagram showing the outline | summary of a friction testing machine.

  The present invention will be described more specifically with reference to examples of the evaluation method for printed matter fastness according to the present invention.

  Various combinations of printed materials A to C shown in Table 1 were prepared, and the fastness was evaluated using the method according to the present invention. All printed matter was produced by a commercially available ink jet printer with pigment ink. As the printing medium, a coated paper exclusively for inkjet was used.

  An outline of the friction tester used for the evaluation is shown in FIG. In this example, a friction tester manufactured by Imoto Seisakusho Co., Ltd. and a wear resistance tester A partially modified were used. This conforms to the friction tester type II (commonly known as Gakushoku type friction tester) defined in JIS L0849.

An initial print medium on which no image or character is formed is attached as the test piece 2 to the load portion 1 at the end of the arm, and various printed materials shown in Table 1 as the printed material 3 are fixed to the stage portion where the load slides. did. In the present testing machine, both of the parts to be fixed had a kamaboko shape, and the contact area between the test piece 2 and the printed material 3 was approximately 60 mm ² .

  In addition, there is no limitation in particular about the friction tester used for this invention, All will be used suitably if it is a thing which does not impair the meaning. That is, it is only necessary that the test piece is brought into contact with the printing surface of the printed matter, the test piece is rubbed a predetermined number of times with a uniform load, and then the printed matter and the test piece can be used for each measurement. Specifically, in addition to the above-described friction tester type II, a product obtained by partially modifying a clock meter (dyeing fastness tester) is also suitable.

  The load 1 was set to 500 g (including the weight of the arm, etc.), and the friction was performed by reciprocating the stage on which the printed material 3 was fixed. At this time, since the arm supporting the load 1 is freely movable in the vertical direction, the test piece 2 is always pressed against the surface of the printed matter 3 by the load 1 with a uniform force.

  And the optical density of the friction surface of the test piece 2 and the glossiness of the friction surface of the printed matter 3 were measured every predetermined number of times, and the amount of change was obtained.

  As a method for measuring the optical density, any of various widely known methods can be suitably used. ISO 13660 defines a method for measuring optical density as one of image quality attributes relating to graphic images, and is widely used. In this example, the optical density was measured using Personal IAS, an image quality evaluation system manufactured by QEA of the United States based on ISO 13660.

  As for the glossiness, any of various commonly known measurement methods can be suitably used in the present invention. As an example, JIS Z8741 has a glossiness measurement method in which a light beam having a specified opening angle is incident on the sample surface at a specified incident angle and the light beam having a specified opening angle reflected in the specular reflection direction is measured by a light receiver. It is prescribed. In this example, glossiness (60 ° glossiness) was measured using a gloss meter, IG-330, manufactured by HORIBA, Ltd.

  Table 2 shows the measured values and evaluation values, and further, as a reference, the results of visual sensory evaluation of the printed surface under the same conditions in three stages of ○, Δ, and × on the friction surface of the printed material using the conventional method. The evaluation value here is a parameter uniquely obtained by the following formula 1.

Formula 1
Evaluation value = {(change amount of optical density) × A + B} × {(change amount of glossiness) × C + D}
A = −50 in this example
B = 10 in this example
C = 0.2 in this example
D = 10 in this example
The coefficients A, B, C, and D in Equation 1 can be appropriately optimized and used according to the evaluation object, purpose, and judgment criteria. For example, if the application does not place importance on the change in the optical density, the value of A may be lowered, and if it is not desirable to change the glossiness, the sign of C may be reversed.

  In this example, both the “change in optical density” and the “change in glossiness” are regarded as equally important, and the coefficients A, B, C, and D are set so that the initial value becomes 100.

  As can be seen from the results in Table 2, according to the present invention, the change can be detected more sensitively from the initial stage than in the conventional sensory evaluation method of the friction surface of the printed matter.

  As described above, by using the evaluation method according to the present invention, the fastness of the printed matter including the initial stage can be made sensitively and accurately, and relatively easily and in a short time.

1 Load 2 Specimen 3 Printed matter

Claims (2)

A robustness evaluation apparatus for printed matter in which images and characters are formed using an inkjet device and ink on a printing medium,
Using the same printing medium as the printed matter to be evaluated, on which no images or characters are formed, as a test piece, bringing the test piece into contact with the printed surface of the printed matter,
Measure the amount of change in the optical density of the friction surface of the test piece and the change in glossiness of the friction surface of the printed matter by rubbing the test piece a predetermined number of times with a uniform load applied,
A robustness evaluation apparatus for printed matter, characterized in that the fastness is evaluated by comparing the measured value and an evaluation value calculated from the measured value with a predetermined arbitrary reference value. A method for evaluating the robustness of a printed material for evaluating the robustness of a printed material in which images and characters are formed using an inkjet device and ink on a printing medium,
A contact step in which the same print medium as the print to be evaluated, on which no image or character is formed, is used as a test piece, and the test piece is brought into contact with the printed surface of the print;
A measurement process for measuring the amount of change in optical density of the friction surface of the test piece and the amount of change in glossiness of the friction surface of the printed matter by rubbing the test piece a predetermined number of times with a uniform load applied, and ,
A method for evaluating the robustness of printed matter, comprising: a step of comparing the measured value and an evaluation value calculated from the measured value with a predetermined arbitrary reference value.