JP2009023217A - Ink-jet recording method and inkjet recording device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an easy-to-use inkjet recording method and an inkjet recording device keeping or improving coloring property of a recorded matter, and improving lightfastness of the recorded matter. <P>SOLUTION: In the inkjet recording method and inkjet recording device for ejecting ink and recording a recording object on a recording medium, light-fast protective materials optimum to respective inks, specifically the light-fast protective materials having absorbing waves for the absorbing wave bands in the visible regions of the respective inks, are applied onto printing regions of the respective inks. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an ink jet recording method and an ink jet recording apparatus for recording on a recording medium by discharging ink. In particular, the present invention relates to a method and apparatus for improving color development and light fastness of recorded matter recorded using ink.

  In an ink jet system in which ink is ejected and recorded on a recording medium, various inks having different performances are used. Some inks have excellent color developability but insufficient weather resistance. For example, many dye inks using a dye as a coloring material apply to this. Weather resistance is superior to dye inks, but some inks have slightly poorer color development. For example, many pigment inks using a pigment as a coloring material apply to this. In addition, there are various uses of recorded matter. In addition to the color developability of recorded matter, there are many applications that require a good weather resistance at the same time. For example, recorded matter using a backlit film is used under harsh conditions in which it is constantly exposed to fluorescent light with high illuminance. An ink jet recording system that satisfies both color development and weather resistance is desired.

  In order to achieve this goal, various inks and recording media suitable for the ink jet system have been developed. However, there are many conditions to be considered in order to achieve the target, and many problems remain to be overcome in order to realize by improving the material alone such as ink and recording medium. Of course, the conditions to be considered also include conditions relating to the trade-off between color development and weather resistance of recorded matter recorded using ink.

  Various methods for protecting a recorded matter recorded on a recording medium by ejecting ink by some method have been studied. This is considered to be one of the directions that should be considered in that it can alleviate the restrictions and problems of the material alone such as ink and recording medium. For example, Patent Document 1 proposes a method of protecting a recorded material by laminating various plastic films. Patent Document 2 proposes a method in which a protective liquid is ejected by an ink jet method and is adhered to an image region or the entire surface of a recording medium.

However, simply applying these methods may cause problems such as undesired color changes in recorded matter recorded using ink, and can satisfy various market demands in recent years. Not.
JP 2001-158092 A JP 2000-225695 A

  INDUSTRIAL APPLICABILITY The present invention is an ink jet recording method and an ink jet recording apparatus for recording on a recording medium by ejecting ink, and maintaining or improving the color developability of the recorded matter, and improving the light resistance of the recorded matter. An object is to provide an ink jet recording method and an ink jet recording apparatus.

  In order to solve the above-described problems, an ink jet recording method of the present invention is an ink jet recording method in which ink is ejected and recorded on a recording medium. The ink is printed on the recording medium, and the ink is printed on the ink printing area. A light-resistant protective material having an absorption wavelength in the visible absorption wavelength band is applied.

  Further, the light-resistant protective material has an ultraviolet absorption property.

  The light-resistant protective material contains a pigment having the same color as the ink.

  Further, the recording medium is light-transmitting.

  In addition, the application of the light-resistant protective material is performed using an ink jet method in which the light-resistant protective material is discharged.

  In order to solve the above problems, an ink jet recording apparatus according to the present invention comprises: means for mounting ink and discharging the ink to print on the recording medium in the ink jet recording apparatus that records ink on the recording medium. A means for mounting a light-resistant protective material having an absorption wavelength in the absorption wavelength band in the visible region of the ink, and discharging the light-resistant protective material and applying the material on the recording medium; and on the recording medium on which the ink is printed. It has a control means or an algorithm for recognizing the area and applying the light-resistant protective material to the print area of the ink.

  According to the present invention, it is possible to provide an ink jet recording method and an ink jet recording apparatus that are easy to use and can improve the weather resistance of a recorded matter while maintaining or improving the color developability of the recorded matter. .

Hereinafter, the ink jet recording method and the ink jet recording apparatus of the present invention will be described with reference to the drawings. However, the contents of the present invention are not limited thereto.
Various inks can be selected in an ink jet recording system in which ink is ejected and recorded on a recording medium, but it is currently difficult to satisfy both color development and light resistance with only ink. The inventors of the present invention focused on this point, and as a result of intensive studies, they have reached the present invention. According to the present invention, since the light-resistant protective material having an absorption wavelength in the visible absorption wavelength band of the ink is applied to the ink print region, the color development of the recorded matter is maintained or improved. Light resistance can be improved, and it is also possible to use an ink that is inferior in light resistance but good in color developability.

  A variety of inks can be used, including inks with poor light resistance, but inks that develop color by absorbing light are preferred. The optical density is improved by the lamination effect with the light-resistant protective material having the absorption wavelength in the visible absorption wavelength band of the ink, and the color developability is improved. As a result, an ink having a small volume ratio of the color material on the recording medium is also preferable. The optical density is improved by the effect of filling the optical gap viewed from the observation direction with a light-resistant protective material having an absorption wavelength in the visible absorption wavelength band of the ink, and the color developability is improved. A dye ink is an example of an ink suitable for the present invention.

  The light-resistant protective material of the present invention has an absorption wavelength in the visible absorption wavelength band of the ink used. Therefore, as described above, the color developability is improved. In addition, light that has passed through a light-resistant protective material having an absorption wavelength in the ink absorption wavelength band has reduced energy in a wavelength band that affects light resistance, and light resistance is improved. The light-resistant protective material preferably has ultraviolet absorption. Since it is not in the visible range, an effect of improving color developability cannot be expected. The light-resistant protective material preferably contains a pigment having the same color as the ink. For example, if a system using pigment ink as a light-resistant protective material is used, in addition to improving color development and light resistance, the pigment ink can be used for other purposes, and can be widely used as a system. .

  The arrangement of the light-resistant protective material is preferably arranged so as to wrap the color material component of the ink when the irradiation light to the color material of the ink is isotropic. In the case where the light irradiation to the ink color material is unidirectional, it is also preferable to protect the ink by arranging it only in one direction of the color material component of the ink. For example, when a recorded matter using a backlit film is displayed by irradiating a fluorescent lamp from the back side, a unidirectional factor is a strong example. Further, it is preferable not to apply a light-resistant protective material to the non-printing area of the ink. In general, the transmittance in the visible range cannot be made 100% with any protective material, which causes dullness in the non-printing area of the ink. That is, as long as other color development improvement effects are not achieved, it becomes a cause of color development degradation.

  Hereinafter, an example in which the ink print area is protected in one direction will be described. FIG. 1 is a schematic view of an example in which a light-resistant protective material is disposed in an ink printing area. (A) is a view as seen from the ink printing direction, and (b) is a view as seen from the cross-sectional direction of the recording medium 101. The recording medium 101 includes a base material 102 and an ink receiving layer 103. A one-dot ink print area 104 printed on the recording medium 101 is protected from above (b) by a light-resistant protective material 105.

  FIG. 2 is a schematic diagram of an example in which the ink printing area is isotropically protected. (A) is a view as seen from the ink printing direction, and (b) is a view as seen from the cross-sectional direction of the recording medium 101. The recording medium 101 includes a base material 102 and an ink receiving layer 103. A 1-dot ink print area 104 printed on the recording medium 101 is isotropically protected by a light-resistant protective material 105.

  Hereinafter, the color development improvement effect described above will be described with reference to the drawings. This is an example of applying various protective materials to a recording medium having translucency, irradiating light from the back surface of the recorded material, and observing from the surface of the recorded material. FIG. 3 shows the transmittance of an example in which a light-resistant protective material having an absorption wavelength in the absorption wavelength band in the visible region of ink is applied to the ink printing region. Due to the stacking effect, the ratio (contrast) between the transmittance of the transmission wavelength and the transmittance of the non-transmission wavelength is improved, and the color development is improved. FIG. 4 shows the transmittance of an example in which a protective material having no absorption wavelength in the visible absorption wavelength band of ink is applied to the ink printing region. As described above, in general, the transmittance in the visible region cannot be made 100% with any protective material, and the contrast deteriorates when the ink has no absorption wavelength in the absorption wavelength band in the visible region. FIG. 5 shows the transmittance of an example in which a protective material having no absorption wavelength in the visible absorption wavelength band of ink is applied to the non-printing area of the ink. The transmittance is lowered in the entire wavelength range, and it is not preferable unless there is another purpose.

  As a method for applying the light-resistant protective material, various methods that can achieve the above can be selected. In particular, the ink jet recording method is preferable. A light-resistant protective material can be applied in the form of dots. In addition, the dot shape and size of the light-resistant protective material can be set relatively easily to the shape and size close to the dot shape and size of ink. As a result, the control method can be simplified.

  The light-resistant protective material coating apparatus of the present invention can be incorporated in an ink jet recording apparatus, and is preferable. By incorporating it, it is possible to exchange the print area information of the ink printed by the apparatus itself within the apparatus, and it becomes easy and simple to recognize the print area of the ink. At the same time, it is preferable to incorporate a control means or algorithm for applying a light-resistant protective material to the recognized ink print area according to the method of the present invention. Most of the operations can be automated, and the apparatus can be simple and convenient for the user. Further, the entire inkjet recording apparatus including the light-resistant protective material coating apparatus can be reduced in size and cost.

  Although the Example of this invention is shown below, the content of this invention is not limited by this.

  <Evaluation sample creation 1>

First, a recorded matter on which three types of ink were printed was prepared. Specifically, three types of dye inks A (cyan), B (magenta), and C (yellow) that have a fading property to light are printed on a commercially available backprint type backlit film for dye ink by an inkjet recording method. Two areas of shading were printed. The back print type backlit film is a recording medium that is printed from the opposite side of the observation surface and irradiated with a fluorescent lamp from the opposite side of the observation surface, for example, in an advertising display at a cosmetic corner of a department store. . The dot arrangement in the light color area is shown in FIG. In the light color region, the dot arrangement of the dye inks A, B, and C was triangular, the dots were circular with a diameter of about 20 μm, the areas were almost the same, and the distance between dots was about 100 μm. In the dark color region, the dot arrangement of the dye inks A, B, and C was triangular, the dots were circular with a diameter of about 20 μm, the areas were almost the same, and the inter-dot distance was about 20 μm.
Next, a light-resistant protective material was applied. Specifically, a light-resistant protective material IA (for cyan), IB (for magenta), and IC (for yellow) having ultraviolet absorptivity and having an absorption wavelength in the visible absorption wavelength band of each ink is used for inkjet. The coating was carried out as shown in FIG. The dots were circular with a diameter of about 30 μm and the area was almost the same. For ink A, all dots of light-resistant protective material IA were applied so as to cover the entire dots 106. Ink B was coated with all dots 109 of light-resistant protective material IB so as to cover the entire dots 108. Ink C was coated with all the dots 111 of the light-resistant protective material IC so as to cover the entire dots 110.

(Comparative Example 1)
A recorded matter was prepared in the same procedure as in Example 1. Do not apply light-resistant protective material.

(Comparative Example 2)
First, a recorded matter is prepared in the same procedure as in Example 1, and then the light-resistant protective material II that absorbs ultraviolet rays as much as in Example 1 covers the entire region including all the dots of inks A, B, and C. It was applied as follows.

<Evaluation 1>
(Light resistance test)
A light irradiation test was performed on the prepared sample under conditions simulating a state in which a back print type backlit film is usually used. Specifically, fluorescent light of about 5000 lux was irradiated for 200 hours from the opposite side of the observation surface, that is, the ink printing side and the light-resistant protective material application side.

(Judgment method)
The degree of initial color development and fading of each ink was evaluated by visual judgment.

The initial color development of each ink is based on the test result of Comparative Example 1 in which the light-resistant protective material is not applied,
○: Improvement can be seen from Comparative Example 1 Δ: Same as Comparative Example 1 ×: Decline from Comparative Example 1 The degree of fading of the ink is based on the test result of Comparative Example 2 in which the light-resistant protective material II is uniformly applied,
○: Improvement can be seen from Comparative Example 2 Δ: Same as Comparative Example 2 ×: Inferior to Comparative Example 2.

(Evaluation results)
The evaluation results are shown in FIG. Comparative Example 1 is not protected by a light-resistant protective material, and a fading color is seen. In Comparative Example 2, the color developability is reduced as compared with Comparative Example 1. This is mainly due to the occurrence of dullness in the light color area. Moreover, although the light resistance improvement is seen with respect to the comparative example 1, it is only protected uniformly with the same light-resistant protective material, and is inferior to Example 1. In Example 1, the color developability is improved as compared with Comparative Example 1. This is because no dullness was observed in the light color area, and density enhancement was observed in the dark color area. Moreover, light resistance is also improved with respect to Comparative Examples 1 and 2. For each color, the effect of protecting with an appropriate light-resistant protective material appears.

  <Evaluation sample creation 2>

  First, a recorded matter on which three types of ink were printed was prepared. Specifically, three types of dye inks Dd (cyan), Ed (magenta), and Fd (yellow) that have a fading property to light are printed on a commercially available back print film for dye inks by using an ink jet recording method. The area of was printed. Back print film is a recording medium that is printed from the opposite side of the viewing surface and is illuminated by light such as fluorescent lamps from both the viewing side and the opposite side, such as a poster display at a product display counter in a department store. It is. The back print film used was based on a film having ultraviolet absorptivity. The dot arrangement was the same as in Example 1. In the light-colored region, the dot arrangement of the dye inks Dd, Ed, and Fd was triangular, the dots were circular with a diameter of about 20 μm, the area was almost the same, and the distance between dots was about 100 μm. In the dark color region, the dot arrangement of the dye inks Dd, Ed, and Fd is triangular, the dots are circular with a diameter of about 20 μm, the areas are almost the same, and the inter-dot distance is about 20 μm.

  Next, a light-resistant protective material was applied. Specifically, pigment inks Dp (cyan), Ep (magenta), and Fp (yellow) were used as light-resistant protective materials for each ink, and were applied in the same manner as in Example 1 by an inkjet method. The dots were circular with a diameter of about 30 μm and the area was almost the same. For the ink Dd, all the dots of the pigment ink Dp were applied so as to cover the entire dot. For the ink Dd, all the dots of the pigment ink Dp were applied so as to cover the entire dot. For the ink Dd, all the dots of the pigment ink Dp were applied so as to cover the entire dot.

(Comparative Example 3)
A recorded matter was prepared in the same procedure as in Example 1. Do not apply light-resistant protective material.

(Comparative Example 4)
The dye inks Dd (cyan), Ed (magenta), and Fd (yellow) of Example 1 are changed to the pigment inks Dp (cyan), Ep (magenta), and Fp (yellow), and the dot diameter of about 20 μm is changed to about 30 μm. The recorded matter was prepared in the same manner as in Example 1 except for the above. Do not apply light-resistant protective material.

<Evaluation 2>
(Light resistance test)
A light irradiation test was performed on the prepared sample under conditions simulating a state in which the back print film is normally used. Specifically, about 1500 lux of fluorescent lamp light was posted for about 14 hours per day for one month while being irradiated from both sides of the observation surface.

(Judgment method)
The degree of initial color development and fading of each ink was evaluated by visual judgment.

The initial color development of each ink is based on the test result of Comparative Example 3 in which no light-resistant protective material is applied,
○: Improvement can be seen from Comparative Example 3 Δ: Same as Comparative Example 3 ×: Inferior to Comparative Example 3. The degree of fading of the ink is based on the test result of Comparative Example 3 in which the photoprotective material is not applied,
○: Improvement can be seen from Comparative Example 3 ×: Same as Comparative Example 3.

(Evaluation results)
The evaluation results are shown in FIG. Comparative Example 3 is not protected by a light-resistant protective material, and a fading color is seen. Comparative Example 4 shows a significant decrease in color developability compared to Comparative Example 3. Specifically, lack of density and uneven color were remarkable. This is because the color material in the pigment ink does not sufficiently reach the film side, that is, the observation side through the ink receiving layer. Moreover, since the initial color development was significantly inferior to Comparative Example 3, the light resistance could not be judged as superior or inferior. In Example 2, the color developability is improved as compared with Comparative Example 3. This is because no dullness was observed in the light color area, and density enhancement was observed in the dark color area. In addition, the light resistance is improved as compared with Comparative Example 3. The effect of being appropriately protected against light from the back side appears.

The schematic diagram of an example which has arrange | positioned the light-resistant protective material in the printing area | region of an ink. The schematic diagram of another example which has arrange | positioned the light-resistant protective material in the printing area | region of an ink. The transmittance | permeability of an example which apply | coated the light-resistant protective material which has an absorption wavelength in the absorption wavelength range of the visible region of an ink to the printing area | region of an ink. The transmittance | permeability of an example which apply | coated the protective material which does not have an absorption wavelength in the absorption wavelength band of the visible region of an ink to the printing area | region of an ink. The transmittance | permeability of an example which apply | coated the protective material which does not have an absorption wavelength in the absorption wavelength band of the visible region of an ink to the non-printing area | region of an ink. FIG. 3 is a schematic diagram illustrating dot arrangement of inks A, B, and C. FIG. 3 is a schematic diagram showing the arrangement of a light-resistant protective material for each dot of inks A, B, and C. The evaluation result table of evaluation 1. The evaluation result table of evaluation 2.

Explanation of symbols

DESCRIPTION OF SYMBOLS 101 Recording medium 102 Base material 103 Ink receiving layer 104,106,108,110 Ink printing area 105,107,109,111 Light-resistant protective material

Claims (6)

In an inkjet recording method for recording on a recording medium by discharging ink,
Print ink on a recording medium,
An ink jet recording method comprising applying a light-resistant protective material having an absorption wavelength in the visible absorption wavelength band of the ink to a print region of the ink.   2. The ink jet recording method according to claim 1, wherein the light-resistant protective material has ultraviolet absorptivity.   The ink jet recording method according to claim 1, wherein the light-resistant protective material contains a pigment having the same color as the ink.   The inkjet recording method according to claim 1, wherein the recording medium has translucency.   5. The ink jet recording method according to claim 1, wherein the light resistant protective material is applied using an ink jet method in which the light resistant protective material is discharged. In an inkjet recording apparatus for recording on a recording medium by discharging ink,
Means for mounting ink and discharging the ink to print on a recording medium;
Means for mounting a light-resistant protective material having an absorption wavelength in the absorption wavelength band of the visible region of the ink, and discharging the light-resistant protective material and applying it on a recording medium;
An ink jet recording apparatus comprising: a control unit or an algorithm for recognizing an area on a recording medium on which the ink is printed and applying the light-resistant protective material to the ink printing area.

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