JP4695338B2 - Ink set for ink jet recording, ink jet recording method and recorded matter using the same - Google Patents

Description

  The present invention relates to an ink jet ink set made of an ink using an inorganic pigment as a color material, an ink jet recording method using the ink set, and a recorded matter. More specifically, an inorganic ink jet ink set that is excellent in light resistance, sharpness, and gradation, can express a wide color gamut, and can be colored regardless of the substrate, and uses the same The present invention relates to an ink jet recording method and recorded matter.

  Conventionally, when coloring inorganic materials such as ceramics and metals, heat resistance, stability and light resistance have been emphasized. From these viewpoints, inorganic pigments are mainly used as coloring materials, and are fixed by firing. Is adopted.

  In recent years, in these fields, due to the advancement of design trends, various studies have been conducted on color variations of inorganic pigments, and many intermediate colors (colors other than the three primary colors (red, blue, yellow) and black) have a wide color gamut. Is proposed).

  These are proposed not as a mixture of colors in principle, but as the color of the inorganic pigment itself. This is because combining inorganic pigments may cause discoloration or discoloration depending on conditions such as the firing temperature.

  The cause of decoloration or discoloration is considered to be that when a plurality of inorganic pigments are baked at a time, the inorganic pigments cause an interaction and the crystal structure changes.

  Accordingly, when using color materials having different firing temperatures, it is necessary to perform a plurality of firing steps, which results in poor color reproducibility.

  As a method for solving the above problem, in [Patent Document 1], in order to improve color reproducibility, a specific inorganic pigment is colored in the order of cyan, yellow, magenta, and black, and then fired once. It has been found that coloring can be performed with excellent color reproducibility.

  However, this method is excellent in color reproducibility, but if the coloring order is different, the expected intermediate color cannot be obtained, and there is a possibility that decoloring or discoloration may occur, so that the usefulness is poor.

  Moreover, since there is no change in the method by handwriting, industrial applicability is poor, and special coloring such as gradation is naturally impossible.

  On the other hand, inkjet recording is attracting attention in the printing industry. This is because various expressions are possible with small lots and short delivery times, and industrial production is also possible.

  Therefore, there is a demand for a technique for applying an inorganic pigment by inkjet by applying these.

  However, when inorganic pigments are used in ink jets, various problems have arisen due to their special characteristics, and they have not yet been put into practical use.

  One of the main causes is that intermediate colors in ink-jet recording are expressed by mixing ink on a base material, so it is necessary to bake in a state where inorganic pigments are mixed. This is because a problem may occur.

  Also, in the expression of the red component, the color expression is poor or not clear even when used as a single item due to the characteristics of the inorganic pigment, and the red component is weak when an image is formed. It is felt and cannot get a sense of quality.

  On the other hand, [Patent Literature 2] and [Patent Literature 3] can be cited as prior art using an inorganic pigment for inkjet. The former maintains the ejection stability in the ink jet system by adjusting the average particle size of the inorganic pigment and preventing sedimentation, and the latter is a specific inorganic pigment with a dispersant, solvent, glass frit, and dissipation. Addition of foaming agent improves discharge stability and adhesiveness.

  However, these are all intended to improve the ejection stability, and there is no description regarding color expression unique to inkjets using inorganic pigments. That is, it is difficult to express intermediate colors, and the advantages of inkjet that can express a design such as gradation and a wide color gamut cannot be exhibited effectively.

  As described above, the prior art for solving such a problem has not been established yet, and there is a demand for the use of an inorganic pigment for effective ink jetting.

JP 60-234899 A JP 2001-55530 A JP 2001-81363 A

  An object of the present invention is to solve the above-described problems of the prior art, and in particular, an ink jet ink set using an inorganic pigment as a coloring material, which has excellent sharpness and does not discolor or discolor even during firing. Another object of the present invention is to provide an ink-jet ink set capable of expressing an intermediate color and having a wider color gamut, an ink-jet recording method using the ink set, and a recorded matter.

  As a result of diligent efforts to achieve the above object, the inventors of the present invention are equipped with two colors of inorganic pigments of the red component, and other colors are selected as specific inorganic pigments and used as an ink set, thereby clearing the image. Has been found that it is possible to express intermediate colors without discoloration or decoloring even after firing. The invention has been completed.

  That is, the present invention is an ink-jet ink set composed of an ink using an inorganic pigment as a color material, wherein the red component of the ink set is at least two colors of magenta ink composed of gold purple and red ink composed of cadmium red. Ink-jet ink sets characterized by comprising:

  Also, an ink jet ink set made of an ink using an inorganic pigment as a color material, the red component of the ink set being magenta ink made of gold purple and red ink made of cadmium red, and yellow ink and cyan ink The ink-jet ink set is characterized by comprising at least four inks.

  Preferably, the inkjet ink set is characterized in that the yellow ink is an ink composed of cadmium yellow and the cyan ink is composed of cobalt aluminum chrome blue.

  Also, an inkjet ink set made of an ink using an inorganic pigment as a color material, wherein the red component of the ink set is a magenta ink made of gold purple and a red ink made of cadmium red, and a yellow ink made of cadmium yellow And an ink set for ink-jet printing comprising at least five inks including a cyan ink made of cobalt aluminum chrome blue and a black ink.

  Preferably, the inkjet ink set is characterized in that the black ink is an ink made of cobalt ferrite black.

  Preferably, an ink jet recording method is characterized in that, using such an ink set, recording is performed by an ink jet method to form an image on a substrate, followed by firing.

  Preferably, the ink jet recording method is characterized in that the base material is made of an inorganic material, and an ink receiving layer made of glass frit is formed on the surface of the base material before recording by the ink jet method.

  Preferably, the ink jet recording method is characterized in that after recording an image on a base material by an ink jet method and forming an image, all inorganic pigments are simultaneously fired on the base material by one firing.

  And this invention exists in the recorded matter obtained by the above method.

  As described above, the ink set for inkjet recording according to the present invention is excellent in sharpness, capable of expressing a wide color gamut without being discolored or decolored, and can be colored without selecting a substrate. . Furthermore, since high quality peculiar to inkjet such as density and image quality can be sufficiently expressed, inkjet recorded matter using inorganic pigments corresponding to the recent improvement in design ability can be provided.

Hereinafter, the present invention will be described in more detail.
The coloring material used in the present invention is an inorganic pigment, and specifically comprises a metal, a metal oxide, or a metal salt. Although these are stable to heat and light, they have a property of poor color expression due to their structure and are easily decomposed by oxidation / reduction.

  Therefore, in the ink jet recording of inorganic pigments, the color gamut is generally narrow and the red component is particularly weak. Therefore, in the present invention, the magenta ink and the red ink are provided to widen the red color gamut, thereby expressing the so-called intermediate color. It is supported by making it possible.

  That is, the ink set needs to include at least two colors of magenta ink made of gold purple and red ink made of cadmium red.

  The cadmium red in the present invention includes zirconium silicate cadmium inclusion red coated with zirconium silicate or the like.

Here, the red ink in the present invention means that the hue when the ink is baked is a counterclockwise with the a ^* axis (+) being 0 ° in the a ^* b ^* space coordinates of the CIEL ^* a ^* b ^* equal color space. Ink around the range of 10 ° to 50 °. Similarly, magenta ink refers to ink in the range from 0 ° to 10 ° and in the range from 330 ° to 360 °. However, the closer to the origin, the lower the saturation, and the closer to the black, the more the distance from the origin is 10 or more.

  Equipped with magenta ink and red ink to widen the red color gamut, which is weak in color expression, and to obtain an appropriate intermediate color when mixed with other colors (for example, yellow or cyan). is there.

  For example, if you want to express orange, you can express yellow and red ink, and if you want to express purple, magenta ink and cyan ink are ejected and mixed on the base material to express a clear intermediate color. it can.

  Note that a clear orange cannot be obtained by mixing yellow ink and magenta ink, and a clear purple cannot be obtained by mixing red ink and cyan ink.

  The reason why magenta is gold purple and red is cadmium red is that it is excellent in color sharpness and density after firing and is suitable for an ink jet system. Furthermore, even when these two colors or one of them and another inorganic pigment are baked in a state where the ink dots overlap, it is a relatively stable property that hardly causes an interaction.

  Further, an ink set including yellow ink and cyan ink in addition to magenta ink and red ink is preferable.

  This is to express a color gamut suitable for an ink jet system that generally forms a full-color image. By including these four colors, any intermediate color can be expressed.

  Specifically, inorganic pigments that can be used as yellow are lead antimony yellow, yellow lead 10G, yellow 5G, yellow lead G, yellow lead, cadmium yellow, yellow iron oxide, reinforced yellow iron oxide, ocher, titanium yellow, titanium Examples thereof include barium nickel yellow, vanadium tin yellow, vanadium zirconium yellow, praseodymium yellow, chromium titanium yellow, antimony titanium chromium yellow, and antimony titanium yellow, and cadmium yellow is preferable.

  The cadmium yellow used in the present invention includes a composite salt of cadmium sulfide and zinc sulfide, a composite salt of cadmium sulfide and barium sulfate, a composite salt of cadmium sulfide, zinc sulfide and barium sulfate, and cadmium sulfide as zirconium silicate. Also included are cadmium zirconium silicate inclusion yellow and the like coated with the like.

  Examples of inorganic pigments that can be used as cyan include bitumen, cobalt blue, ultramarine blue, cerulean blue, and cobalt aluminum chrome blue. Cobalt aluminum chrome blue is preferred.

  Even when these preferred forms of inorganic pigments are mixed and fired with the magenta gold purple or red cadmium red of the present invention, they exhibit an intermediate color without any problem of decoloring or discoloration at the firing temperature. This is because an expression having a wider color gamut is possible as compared with the conventional case.

  More preferably, the ink set includes black ink in addition to magenta ink, red ink, yellow ink, and cyan ink.

  In general, black is obtained by mixing yellow, magenta, and cyan, but the hue changes due to a slight difference in distribution, so if black ink is included as a single color, the problem is solved and a stable colored product is obtained. It is because it can do.

  Specific examples of inorganic pigments that can be used as black include lamp black, furnace black, charcoal black, ivory black, graphite, iron black, manganese ferrite black, cobalt ferrite black, copper chrome black, and copper chrome manganese black. However, cobalt ferrite black is preferable. This is because there is no decolorization or discoloration when mixed with other colors and baked.

  In addition to these, it is also possible to include ink made of white, green, metallic, pearl, etc. in the ink set. This is because as the number of colors increases, it becomes possible to adjust a subtle color difference, and a more delicate expression can be achieved. However, the ink preparation, the number of ink jet heads, the ink jet recording time, and the like are affected, and should be used arbitrarily.

  Specific examples of inorganic pigments that can be used as white include lead white, zinc white, lithopone, titanium dioxide (anatase type), titanium dioxide (rutile type), zinc sulfide, antimony oxide, precipitated calcium carbonate, heavy calcium carbonate , Kaolin, mica, precipitated barium sulfate, barite powder, gloss white, alumina white, talc, silica, calcium silicate, cerium oxide and the like. Specific examples of inorganic pigments that can be used as green include chrome green, chromium oxide, viridian, cobalt green, cobalt chrome green, and titanium cobalt green. Specific examples of the inorganic pigment that can be used as the metallic include aluminum powder, copper powder, lead powder, tin powder, and zinc powder. Specific examples of inorganic pigments that can be used as pearls include titanium mica.

  Further, glass frit can be added to the inorganic pigment ink for the purpose of providing adhesiveness. The glass frit is mainly composed of silicon dioxide, and is used with an auxiliary agent added depending on the purpose of use. Adjuvants include lithium carbonate, sodium carbonate, potassium carbonate, lead oxide, bismuth oxide, barium carbonate, strontium carbonate, calcium carbonate, magnesium carbonate, zinc oxide, aluminum oxide, aluminum hydroxide, boric acid, zirconium oxide, titanium oxide Furthermore, a mixture of natural products such as feldspar, quartzite, borax, kaolin and the like can also be added. These materials can be used alone or in a mixed form.

  Of course, it is also possible to add glass frit from the stage of inorganic pigment synthesis (hereinafter referred to as “upper”) instead of a mixture of inorganic pigment and glass frit.

  The inorganic pigment in the ink composition used in the present invention, the inorganic pigment and the glass frit, or the medium in which the upper paint is dispersed includes water, an organic solvent, a wax, or a mixture thereof, and is not particularly limited.

  Furthermore, when dispersing an inorganic pigment, or an inorganic pigment and glass frit, or an overpaint into the ink, various surfactants can be optionally used alone or in the form of a mixture. .

  Specifically, fatty acid soap, alkyl succinic acid sodium salt, alkylbenzene sulfonic acid sodium salt, alkyl naphthalene sulfonic acid sodium salt, alkyl sulfate sodium salt, polyoxyethylene alkyl ether sodium sulfate salt, dialkyl as anionic surfactant Cationic surfactants such as sulfosuccinate sodium salt, sodium alkyl phosphate, styrene maleic anhydride copolymer, olefin maleic anhydride copolymer, polyacrylamide partial hydrolyzate, acrylamide acrylate copolymer, sodium alginate Alkyltrimethylammonium chloride, alkyldimethylbenzylammonium chloride, etc. as agents, polyoxyethylene alkyl ethers, polyoxins as nonionic surfactants, etc. Polyoxyethylene alkyl allyl ethers, sorbitan fatty acid esters such as alkyl betaine amphoteric surfactant, an amide betaine. As the anionic surfactant, not only a sodium salt but also any metal salt or ammonium salt can be used.

  In addition, additives such as surface tension adjusters, viscosity adjusters, specific resistance adjusters, heat stabilizers, antioxidants, anti-reducing agents, preservatives, pH adjusters, antifoaming agents, wetting agents, etc. Of course, it is also possible to add.

  The inorganic pigment ink can be obtained by mixing the above materials, further dispersing the mixture using a dispersing machine such as a roll mill, a ball mill, a colloid mill, a jet mill, a bead mill, or a sand mill, followed by filtration.

  Furthermore, if necessary, it is possible to suppress bleeding after ink ejection landing by providing a liquid-absorbing material on the substrate as an ink receiving layer.

  Preferably, by providing an ink-receiving layer made of glass frit on the substrate, an image free from bleeding phenomenon is formed after recording and after baking, and further using an unfired glass frit as the receiving layer, an inorganic pigment and A glass film having excellent adhesion can be formed by melting and mixing the glass frit in the ink and the glass frit in the receiving layer.

  Accordingly, the glass frit used in the ink receiving layer is preferably the same as the glass frit that can be added to the ink described above, or a glass frit having a similar softening point and expansion coefficient even if different. This is because if the difference is significantly different, adhesion failure or the like occurs.

The drying application amount of the glass frit is preferably 50 to 500 g / m ² . If it is less than 50 g / m ² , ink bleeding cannot be sufficiently suppressed, and if it exceeds 500 g / m ² , the fired glass frit layer becomes too thick, and cracks may occur. is there.

  The glass frit used as the ink receiving layer is desirably a glass frit containing about 2 to 10% of cadmium in its components.

  This is because, by using a cadmium-containing glass frit in the ink combination, the color developability of the inorganic pigment after firing is significantly improved.

  An adhesive may be added to the ink receiving layer made of the glass frit of the present invention as necessary. This is because there is an effect of improving workability when applying the ink receiving layer. Specifically, natural polymers such as starch, natural gum, vegetable protein, seaweed, casein, and gelatin, semi-synthetic polymers such as ether type cellulose, ester type cellulose, ether type starch, ester type starch, and processed natural gum , Polyvinyl alcohol, polyethylene glycol, polyvinyl acetate, polyvinyl butyrate resin, polyvinyl acrylate resin, polyvinyl methyl resin, cross-linked polyacrylic acid, polyacrylic acid soda, polyacrylic acid ester, polyacrylamide, sodium methacrylate, polybutadiene, polyurethane , Synthetic polymers such as polyester and polylactic acid.

  Moreover, it is naturally possible to add additives such as a dispersant, an antioxidant, an anti-reduction agent, and a pH adjuster as necessary.

  Examples of the base material used in the present invention include ceramic materials such as glass, ceramics, pots and tiles, and inorganic materials such as metals, but are not particularly limited.

  Moreover, it is preferable to fire all inorganic pigments at one time. This is because if it is performed a plurality of times, a cost problem is caused and color variation is caused.

  As for the firing temperature, in general, in the case of ceramics, 700 to 850 ° C. in the above method, 1100 to 1300 ° C. for 30 to 60 minutes in the case of glass, 30 to 60 minutes at 500 to 650 ° C. in the case of glass, In the case of firewood, it is 1 to 2 minutes in a baking furnace preheated to 750 to 850 ° C., but in actuality, considering the deformation of the base material used, the type of furnace, etc., the baking time and baking temperature are Is set.

  Moreover, when baking at high temperature of 1100-1300 degreeC, it is desirable to use the thing excellent in heat resistance as an inorganic pigment. Specifically, gold purple as magenta ink, zirconium cadmium silicate inclusion red as red ink, zirconium cadmium silicate inclusion yellow and praseodymium yellow as yellow ink, cobalt aluminum chrome blue as cyan ink, cobalt ferrite as black ink Black.

  On the other hand, as the glass frit used in such a case, a material having an appropriate coefficient of thermal expansion and a softening point is selected. If the coefficient of thermal expansion and the softening point of the base material and the glass frit are significantly different from each other, care must be taken because adhesiveness to the base material is not sufficiently performed and adhesion failure or cracks may be caused.

  For example, in the case where the base material is a glass having a softening point near 600 ° C., the softening point of the glass frit used is selected to be near 600 ° C. or lower than the softening point of the base material, and the softening point is set to around 800 ° C. In the case of tiles and earthenware, the glass frit has a softening point of around 800 ° C. or lower.

  As an inkjet recording method, a charge modulation method, a micro dot method, a charge ejection control method, a continuous method such as an ink mist method, a stem method, a pulse jet method, a bubble jet (registered trademark) method, an electrostatic suction method, and the like Any of the demand methods can be adopted.

  Next, although an Example is given and this invention is demonstrated, this invention is not necessarily limited to this Example.

  Ink was blended for each inorganic pigment according to the following formulation and dispersed using a ball mill disperser. Thereafter, impurities were removed by filtration to prepare a uniform inorganic pigment ink.

[Prescription of ink]
Inorganic pigment x wt%
Frit: 12-3567 (leaded transparent: manufactured by Nippon Fellow) 10% by weight
Dispersant: Carribbon B (polycarboxylic acid type activator: Sanyo Kasei Co., Ltd.) 1% by weight
Wetting agent: Polyethylene glycol 400 (manufactured by NOF Corporation) 10% by weight
Pure water remaining
100% by weight

<Inorganic pigment>
Y (yellow): Cadmium yellow 10% by weight
M (magenta): Gold purple 2% by weight
C (cyan): cobalt aluminum chrome blue 10% by weight
R (red): Cadmium red 10% by weight
K (black): Cobalt ferrite black 10% by weight

Next, an ink receiving layer was formed by the following method.
[Prescription of ink receiving layer]
Glass frit 32117
(Glass flux with cadmium, made by Izawa Pigments) 65% by weight
Polyvinyl alcohol (adhesive: PVA-110, manufactured by Kuraray Co., Ltd.) 5% by weight
Pure water remaining
100% by weight

  The glass frit 32117 was dry dispersed using a ball mill. Next, polyvinyl alcohol and pure water were added, kneaded in a mortar, coated on a tile (pottery: glazed) using a screen, and then dried at 110 ° C. for 10 minutes to form an ink receiving layer on the substrate.

  The above ink was used for the tile having the ink receiving layer, and recording was performed using an ink jet printer under the following recording conditions. After recording, a ceramics electric furnace was used and baked at 800 ° C. for 45 minutes.

[Recording conditions]
B) Nozzle diameter: 70 (μm)
B) Applied voltage: 50 (V)
C) Pulse width: 20 (μs)
D) Drive frequency: 1 (kHz)
E) Resolution: 180 (dpi)
E) Evaluation pattern: 3cm x 3cm matrix

[Evaluation Contents]
The obtained recorded matter was evaluated as follows.
(1) Vividness The color of the recorded matter was visually determined.
○: Vividly expressed without impairing the color of the pigment.
Δ: The color of the pigment is slightly dull and slightly sharp.
X: The color is very dull and not clear.
Evaluation ink (single color)
Recording ink: M, R (total 2 colors)
Ink application amount: 10 nl / mm ²
The evaluation results are shown in Table 1.

(2) Discoloration The color of the recorded matter was visually determined.
◯: Discoloration and decoloration are not recognized in the color of the evaluation pattern, and it is a faithful intermediate color.
Δ: The color of the evaluation pattern is slightly discolored or decolored.
X: The color of the evaluation pattern is clearly discolored or decolored.
Evaluation ink (mixed color)
Recording ink: Y + R, Y + M, M + R, R + C, M + C (5 sets in total)
Ink application amount: 10 nl / mm ²
The evaluation results are shown in Table 2.

(3) Intermediate color expression The color of the recorded material was visually determined to confirm whether intermediate colors such as orange, purple, and green were expressed.
○: The intermediate color is expressed with high density and high saturation.
Δ: An intermediate color is expressed, but the saturation is slightly low and the color is slightly dull.
X: Since the saturation of the intermediate color is low and the color is dull, the color expression is inferior.
Evaluation ink (middle color)
Orange recording ink: (for example, Y + R, Y + M)
Purple color recording ink: (for example, R + C, M + C)
Green color recording ink: (for example, Y + C, G)
Ink application amount: 5, 10, 20, 40 nl / mm ² (4 × 4 mode in total)
The evaluation results are shown in Table 2.

(4) Pattern expression Pattern creation (JIS-X9201 N3 image)
Recording ink: All inks described in each example are shown in Table 2.

A recorded matter was prepared and evaluated in the same manner as in Example 1 except that Y of the ink used was changed to praseodymium yellow.
Y (yellow): praseodymium yellow 10% by weight

A recorded matter was prepared and evaluated in the same manner as in Example 1 except that the inks used were six colors Y, M, R, C, G (green), and K, and green was the following inorganic pigment.
G (Green): Titanium cobalt green 10% by weight

Comparative Example 1
A recorded matter was prepared and evaluated in the same manner as in Example 1 except that the red component of the inorganic pigment to be used was changed to only magenta ink.

Comparative Example 2
Chrome tin pink was used as magenta ink and Bengala was used as red ink. Other steps were the same as in Example 1.

  As is apparent from Tables 1 and 2, the ink jet recordings of Examples 1 to 3 prepared using the ink set for ink jet recording of the present invention can express a clear color, and even in the expression of intermediate colors, A recorded material with a wide color gamut can be obtained without erasing. Further, even when an image is formed, a recorded material with a high-class feeling can be obtained. In particular, by specifying Y, M, R, and C as in Examples 1 and 3, it is possible to create an ink jet recorded matter that is also excellent in neutral color saturation.

Claims (9)

  An ink-jet ink set comprising an ink containing an inorganic pigment as a color material, wherein the red component of the ink set includes at least two colors of ink, magenta ink made of gold purple and red ink made of cadmium red. Ink set for inkjet.   An ink-jet ink set comprising an ink having an inorganic pigment as a color material, wherein the red component of the ink set is a magenta ink comprising gold purple and a red ink comprising cadmium red, and includes at least a yellow ink and a cyan ink An ink-jet ink set comprising four colors of ink.   The inkjet ink set according to claim 2, wherein the yellow ink is an ink made of cadmium yellow and the cyan ink is made of cobalt aluminum chrome blue.   An ink jet ink set made of an ink using an inorganic pigment as a color material, wherein the red component of the ink set is a magenta ink made of gold purple and a red ink made of cadmium red, and a yellow ink made of cadmium yellow, cobalt An ink-jet ink set comprising at least five colors of ink including cyan ink made of aluminum chrome blue and black ink.   The inkjet ink set according to claim 4, wherein the black ink is an ink made of cobalt ferrite black.   An ink jet recording method, comprising: using the ink set according to any one of claims 1 to 5; recording on a base material by an ink jet method to form an image on the base material;   7. The ink jet recording method according to claim 6, wherein the base material is made of an inorganic material, and an ink receiving layer made of glass frit is formed on the surface of the base material before recording by the ink jet recording method.   8. An ink jet recording method according to claim 6, wherein all inorganic pigments are simultaneously baked on the substrate by one baking after recording on the substrate by an ink jet method.   A recorded matter obtained by the method according to claim 6.