JP4963783B2 - Ink set, treatment liquid, recording liquid, image recording apparatus - Google Patents

Description

  The present invention relates to a printing technique in an inkjet printer.

An ink jet recording method for recording an image by using a recording liquid containing a coloring material as droplets is excellent in that the printing mechanism is simple and noise is not generated.
However, on the other hand, this ink jet recording method has a problem that image defects such as character bleeding (hereinafter referred to as feathering) are likely to occur depending on the combination with the recording medium, and the image quality is greatly reduced. For this problem, attempts have been made to reduce feathering by reducing the permeability of the recording liquid. However, if the permeability is reduced, the drying performance of the recording liquid will deteriorate, so if you touch the printed material after printing, the recording liquid will be in your hand. A new problem has arisen, such as sticking or image smearing.

In addition, when printing a color image, since recording liquids of different colors are stacked one after another, color ink is smeared or mixed at the color boundary portion (hereinafter referred to as color bleed), and the image quality is low. A problem that greatly decreases occurs. Regarding this problem, attempts have been made to reduce color bleed by increasing the permeability of the recording liquid. However, if the permeability of the recording liquid is increased, the color material enters the inside of the recording medium, resulting in a decrease in image density. In other cases, the recording liquid oozes out to the back side of the recording material and double-sided printing cannot be performed properly.
Therefore, there is a demand for an image forming method that simultaneously solves these problems and improves image quality.

  In order to solve this problem, a method has been proposed in which a processing liquid containing a component that forms a colorant and an aggregate in the recording liquid is used together with the recording liquid.

It is disclosed that a colorless or light-colored liquid containing a polyvalent metal salt is used as a treatment liquid (see, for example, Patent Document 1). In addition, it is disclosed to use a treatment liquid containing fine particles whose surface is charged in the opposite polarity to the recording liquid in a dispersed state (for example, see Patent Document 2). However, the image quality is still not sufficient.
In particular, since the liquid containing fine particles contains reactive fine particles in a dispersed state, a large amount of reaction components can be added while suppressing an increase in the viscosity of the liquid as compared with the above-described treatment liquid for dissolving the polyvalent metal salt. Moreover, since these fine particles are originally large particles compared with the polyvalent metal salt and the like, large aggregates are formed when the dispersion is lost due to reaction with the coloring material. As a result, a large increase in viscosity occurs, and the fluidity of the color material is suppressed, so that it is highly effective in improving image quality such as feathering improvement.
In a printing method for performing a printing method in which such two liquids are reacted on a recording medium, the processing liquid spreads more widely near the surface of the recording medium as the surface tension of the processing liquid is smaller, and the processing liquid on the surface of the recording medium is better buried. Therefore, the color material in the recording liquid stays on the paper surface, and the image quality such as image density, back-through density, and saturation tends to be improved. In addition, since the processing liquid with low surface tension spreads more widely, a small amount of processing liquid can sufficiently prevent the recording liquid from penetrating into the recording medium due to an agglomeration reaction, and the total liquid volume can be reduced, so feathering, color bleeding, Problems such as cockling can be reduced. A suitable range of the surface tension of the treatment liquid is, for example, 60 [mN / m], more preferably 10 to 40 [mN / m], and if it is less than 10 [mN / m], the treatment liquid is repelled on the nozzle surface. Ink properties cannot be obtained sufficiently and ejection is difficult.
However, in practice, a low surface tension treatment liquid that has a surface tension γ <35 may generate bubbles when the treatment liquid is filled into the nozzle head. Discharge occurs. For this reason, it has been found in the present invention that it is difficult to ensure the discharge stability of all the nozzles, and it may be difficult to stably obtain a high-quality printed matter.

Japanese Patent No. 2675001 JP 2002-332438 A

  SUMMARY OF THE INVENTION Accordingly, a first object of the present invention is to provide an ink set of a recording liquid and a processing liquid that can obtain printed matter with higher image quality. Further, it is a second object to obtain a printed matter with higher image quality by using an ink set of the processing liquid and the recording liquid in which the component structure and properties of the processing liquid and the recording liquid, and the combination of the component structure and properties are adjusted. It is the purpose. Furthermore, it is a third object of the present invention to obtain a printed matter with higher image quality by using an ink set of the processing liquid and the recording liquid in which the composition and properties of the processing liquid and the recording liquid are adjusted, and the combination of the component structure and the properties is adjusted. It is the purpose.

  An object of the present invention is to provide an ink set comprising (1) “a recording liquid containing a coloring material and a processing liquid containing a component having reactivity with a component in the recording liquid. And the recording liquid overlaid on the recording medium, the recording is divided into a layer substantially formed of components constituting the recording liquid and a layer substantially formed of components constituting the processing liquid. An ink set characterized in that the surface tension γ is 10 ≦ γ ≦ 60 [mN / m] ”, (2)“ a recording liquid containing a color material, An ink set comprising a processing liquid containing a component having reactivity with a component in a recording liquid, wherein the recording liquid is substantially removed by superimposing the processing liquid and the recording liquid on a recording medium. A layer formed of constituent components and a component substantially constituting the treatment liquid In the ink set, the surface tension γ is 10 ≦ γ ≦ 40 [mN / m] ”, (3)“ Coloring material ”. An ink set comprising a recording liquid and a processing liquid containing a component having reactivity with the components in the recording liquid, and by substantially superimposing the processing liquid and the recording liquid on a recording medium, The recording liquid is divided into a layer formed by the components constituting the recording liquid and a layer substantially formed by the components constituting the processing liquid, and the processing liquid has a surface tension. Ink set, wherein γ is 10 ≦ γ ≦ 35 [mN / m] ”, (4)“ A recording liquid containing a coloring material and a component having reactivity with the components in the recording liquid ” An ink set comprising a processing liquid, wherein the processing liquid and the recording liquid are superimposed on a recording medium. Thereby forming a recording part which is divided into a layer formed substantially from the components constituting the recording liquid and a layer substantially formed from the components constituting the processing liquid, The treatment liquid has an ink set characterized by a surface tension γ of 10 ≦ γ ≦ 30 [mN / m] ”, (5)“ A recording liquid containing a colorant and reactivity with components in the recording liquid. An ink set comprising a processing liquid containing a component having a layer formed by superimposing the processing liquid and the recording liquid on a recording medium, and a layer substantially formed of the components constituting the recording liquid; The recording liquid is substantially divided into layers formed of components constituting the treatment liquid, and the treatment liquid has a surface tension γ of 10 ≦ γ ≦ 25 [mN / m]. (6) “The treatment liquid is reactive with the components in the recording liquid.” The ink set according to any one of Items (1) to (5) above, wherein the treatment liquid contains an antifoaming agent, wherein the treatment liquid contains a fine particle component. The ink set according to any one of Items (1) to (6), characterized in that the content of the defoaming agent is 0.01 wt% to 10 wt%. This is solved by the ink set described in item (7).

  In addition, the above-mentioned problem is (9) “An image in which an image is formed by superimposing a recording liquid containing a color material and a treatment liquid containing a component having reactivity with a component in the recording liquid on a recording medium. A treatment liquid used in a forming method, wherein the treatment liquid has a surface tension γ of 10 ≦ γ ≦ 60 [mN / m], and is recorded by superimposing the treatment liquid and the recording liquid on a recording medium. The recording portion has a cross section whose layer is formed of a component that is substantially composed of a component that constitutes the recording liquid and a layer that is substantially composed of a component that constitutes the processing liquid. And (10) “a recording liquid containing a coloring material and a processing liquid containing a component having reactivity with the components in the recording liquid are superimposed on the recording medium”. A processing liquid used in an image forming method for forming an image together, wherein the processing liquid A force γ is 10 ≦ γ ≦ 40 [mN / m], and a recording portion is formed by superimposing the treatment liquid and the recording liquid on a recording medium. A processing liquid characterized by being formed by being divided into a layer formed of a component formed from the components constituting the recording liquid and a layer substantially formed of a component constituting the processing liquid ", (11) “A processing liquid used in an image forming method for forming an image by superimposing a recording liquid containing a coloring material and a processing liquid containing a component reactive with the components in the recording liquid on a recording medium. The processing liquid has a surface tension γ of 10 ≦ γ ≦ 35 [mN / m], and a recording portion is formed by overlapping the processing liquid and the recording liquid on a recording medium. A layer whose cross section is formed by components substantially formed by components constituting the recording liquid; A processing liquid characterized in that it is divided into layers that are qualitatively formed from the components constituting the processing liquid ”, (12)“ A recording liquid containing a coloring material, and a reaction between the components in the recording liquid A processing liquid used in an image forming method for forming an image by overlaying a processing liquid containing a component having a property on a recording medium, and the processing liquid has a surface tension γ of 10 ≦ γ ≦ 30 [mN / m]. And a recording section is formed by superimposing the treatment liquid and the recording liquid on a recording medium, and the recording section is a component whose cross section is substantially formed of components constituting the recording liquid. A processing liquid characterized by being formed by being divided into a layer to be formed and a layer substantially formed of components constituting the processing liquid, ”(13)“ a recording liquid containing a coloring material, and An image obtained by overlaying a processing liquid containing a component having reactivity with the component in the recording liquid on the recording medium A processing liquid used in an image forming method to be formed, the processing liquid having a surface tension γ of 10 ≦ γ ≦ 25 [mN / m], and the processing liquid and the recording liquid are stacked on a recording medium. As a result, a recording section is formed, and the recording section is formed of a layer formed of a component that is substantially composed of a component that constitutes the recording liquid and a component that substantially constitutes the processing liquid. A processing solution characterized in that the processing liquid is formed separately from the above-mentioned layers ”, (14)“ the component in the processing liquid having reactivity with the component in the recording liquid is a cationic component ” The processing liquid according to any one of items (9) to (13) ”, (15)“ The processing liquid contains a fine particle component having reactivity with a component in the recording liquid. The treatment liquid according to any one of (9) to (14) ”, (1 ) “The processing liquid according to any one of (9) to (15), wherein the component having reactivity with the component in the recording liquid of the processing liquid is a polyvalent metal salt. (17) “Processing liquid according to (14), wherein the ζ potential of the cationic component is in the range of +5 to +90 [mV]”, (18) “The cationic The treatment liquid according to any one of Items (14) to (17), wherein the component is a cationic pigment ”, (19)“ The cationic component is a cationic dye. The processing liquid according to any one of (14) to (17) above, (20) “Further, an antifoaming agent is included,” (9) to (( 19) The processing liquid according to any one of items ”and (21)“ The content of the antifoaming agent is 0.0. 1 wt% to 10 wt% of the treatment liquid according to item (20) ”, (22)“ The treatment liquid contains a cationic surfactant or a nonionic surfactant. The treatment liquid according to any one of items (9) to (21) ”, (23)“ The treatment liquid contains an acid and is adjusted to a pH of 2 to 7. ” The processing solution according to any one of Items (9) to (22) ”, (24)“ The acid has a temporary dissociation constant pKa in water of 5 or less ”(23) This is solved by the treatment liquid described in the section.

  In addition, the above-described problem is solved by reacting (25) “a recording liquid containing a coloring material and a treatment liquid containing a component having reactivity with the component in the recording liquid, (26) A recording liquid characterized by being used in an image forming method for forming an image divided into a layer formed from constituent components and a layer formed substantially from constituents constituting the processing liquid. ) “The recording liquid according to item (25), wherein the reactive component is anionic”, (27) “The reactive component is a fine particle” The recording liquid according to the item (25) or the item (26) ", (28) any one of the items (25) to (27), wherein the coloring material is a pigment. (29) “The color material is a dye,” (25) Item (25) to Item (29), characterized in that it contains an anionic surfactant or a nonionic surfactant. ), The recording liquid according to any one of items (25) to (30), wherein the component in the reactive recording liquid is an anionic fine particle. Any one of the recording liquids ”, (32), wherein the ζ potential of the anionic fine particles is included in a range of −90 to −5 [mV]. The recording liquid according to any one of Items 1 to 3, (33) “A base is contained and the pH is adjusted to 7 to 12,” any one of Items (25) to (32) above Described recording liquid ”, (34)“ The base has a temporary dissociation constant pKb of 5 or less in water. This is solved by the recording liquid according to item (33).

  In addition, the above-mentioned problem is used in (35) the image forming method for forming an image by reacting a recording liquid containing a color material and a treatment liquid containing a component having reactivity with a component in the recording liquid. In the ink set, the processing liquid is a processing liquid according to any one of the items (9) to (24), and has a reactivity in the processing liquid including a coloring material. Ink set characterized by being used in an image forming method for forming an image by reacting a treatment liquid that reacts with a component ", (36)" A recording liquid containing a color material, and reactivity with components in the recording liquid An ink set for use in an image forming method for forming an image by reacting a processing liquid containing a component having a component, wherein the recording liquid is any one of (25) to (33). A recording liquid containing a coloring material and Ink set characterized in that it is used in an image forming method for forming an image by reacting a processing liquid that reacts with a component having a property ”, (37)“ Surface tension of processing liquid is smaller than surface tension of recording liquid ” The ink set of the processing liquid and the recording liquid according to the above item (35) or (36) ”, (38)“ the difference in surface tension between the recording liquid and the processing liquid is 2 [mN / m The ink set according to any one of (35) to (37) above, wherein (39) “the pH of the treatment liquid is a, and the pH of the recording liquid is b” In this case, the ink set according to any one of (35) to (38) above, wherein (b−a ≧ 2) ”and (40)“ the discharge amounts of the treatment liquid and the recording liquid, respectively. When M1, M2, 0.2 ≦ M1 / M2 ≦ 3.0 It is solved by that the first (35) section to ink set according to any one of the first (39) section. "

  The above-described problem is solved by the ink set according to any one of (41), (1) to (8), or (35) to (40). An image forming method characterized in that it is used; (42) a storage section for storing a recording liquid containing a coloring material and a treatment liquid containing a component having reactivity with a component in the recording liquid; An image forming apparatus including discharge means for individually discharging the recording liquid and the processing liquid, and sequentially discharging the recording liquid and the processing liquid onto a recording medium to form a recording unit; The cross section of the recording part is formed by being divided into a layer formed substantially from the components constituting the recording liquid and a layer formed substantially from the components constituting the treatment liquid. And the processing liquid is any one of the items (1) to (8) or the items (35) to (40). Or the treatment liquid described in any one of (9) to (24) and any of (25) to (34). An image forming apparatus characterized in that it is a combination of recording liquids ”, (43)“ Printed matter characterized in that it is printed by the image forming apparatus described in (42) above ”, ( 44) “A treatment liquid cartridge containing the treatment liquid according to any one of (9) to (24)”, (45) “(25) to (34)” This is solved by a recording liquid cartridge containing the recording liquid according to any one of the items.

According to the present invention, in an image forming method in which two liquids are reacted on a recording medium, an ink set is used in which the two liquids are aggregated so as to form a layer, and most of the color material in the recording liquid does not mix with the processing liquid As a result, the color material is more concentrated near the surface of the recording medium. Therefore, the image recording apparatus using the ink set has a high image density, a low back-through density, a high saturation, and a high image quality. Can be obtained. Further, the lower the surface tension of the treatment liquid, the more the treatment liquid fills the recording medium and the better the penetration of the colorant is. Therefore, the preferred range of the surface tension γ of the treatment liquid is 10 ≦ γ ≦ 60, more preferably 10 ≦ γ ≦ 40, even more preferably 10 ≦ γ ≦ 35, even more preferably 10 ≦ γ ≦ 30, and even more preferably 10 ≦ γ ≦ 25.
Also, in the present invention, in an image forming method in which two liquids are aggregated so as to form a layer in an image formation in which two liquids are reacted on a recording medium, and most of the coloring material in the recording liquid does not mix with the processing liquid. By doing so, since the color material is more concentrated near the surface of the recording medium, it is possible to obtain a high-quality printed material having a high image density, a low back-through density, and a high saturation. At this time, the lower the surface tension of the treatment liquid, the more the treatment liquid fills the recording medium and suppresses the penetration of the coloring material. Therefore, the preferred range of the surface tension γ is 10 ≦ γ ≦ 60, more preferably 10 ≦ γ ≦ 40, even more preferably 10 ≦ γ ≦ 35, even more preferably 10 ≦ γ ≦ 30, and even more preferably 10 ≦ γ ≦ 25.
Furthermore, in the present invention, the component having reactivity with the component in the recording liquid in the processing liquid may be a polyvalent metal salt, and the component having reactivity with the component in the recording liquid in the processing liquid is fine particles. May be.
Furthermore, in the present invention, in the image formation in which the two liquids are reacted on the recording medium, the component having reactivity with the components in the recording liquid is good cationic, and the coloring material contained in the recording liquid is an anionic coloring material. It is desirable that the polarity is opposite to that of the recording liquid.
The fine particles having a ζ potential of +5 to +90 mV as the reactive cationic component contained in the treatment liquid are highly reactive. For this reason, a higher-quality printed matter can be obtained by an image forming method using the treatment liquid containing the cationic fine particles.
In the present invention, when a cationic color material is used as the reactive cationic component contained in the processing liquid, such a cationic color material-containing processing liquid and the recording liquid are reactive, and color bleeding is unlikely to occur. . The colorant may be a pigment or a dye.
In the present invention, the dispersion stability of the component having reactivity with the recording liquid contained in the processing liquid can be enhanced by containing a cationic or nonionic surfactant in the processing liquid. In addition, there is an effect of making the treatment liquid have a lower surface tension.
When the treatment liquid contains an acid and the pH is 2 to 7, the dispersion stability of the component having reactivity with the recording liquid contained in the treatment liquid can be enhanced. When the pH is less than 2, it is difficult to ensure the liquid contact property of the ink head.
Further, when the acid temporary dissociation constant pKa is 5 or less, the dispersion stability of the component having reactivity with the recording liquid contained in the processing liquid can be enhanced.
In addition, it is preferable to use an antifoaming agent in the processing liquid, and by setting the amount to be used (0.001 wt% to 10 wt%), foaming of the processing liquid is suppressed, and non-ejection caused by entraining the foam is prevented. It can prevent and can obtain a printed matter stably. If the concentration of the antifoaming agent is less than 0.001 wt%, a sufficient defoaming effect cannot be obtained, and if it is more than 10 wt%, ejection stability is impaired due to clogging.
Since the recording liquid contains a component having reactivity with the component in the processing liquid, a printed matter with higher image quality can be obtained. Since the anionic color material is particularly excellent in the recording liquid, the recording liquid is preferably anionic. Further, by containing fine particles as a component having reactivity with the component in the processing liquid contained in the recording liquid, a large aggregate is formed when the two liquids come into contact with each other, so that a particularly high-quality printed matter can be obtained. In addition, by using a colorant as a pigment, a durable printed matter having excellent water resistance and light resistance can be obtained.
On the other hand, a vivid printed matter excellent in saturation and brightness can be obtained by using a coloring material as a dye.
Furthermore, by containing an anionic or nonionic surfactant in the recording liquid, it is possible to ensure the dispersion stability of components and color materials that are reactive with the components in the processing liquid contained in the recording liquid. If the component having reactivity with the component in the processing liquid contained in the recording liquid is a fine particle, the aggregate becomes large, and a printed matter with higher image quality can be obtained. In the present invention, if the fine particles contained in the recording liquid are anionic fine particles having a ζ potential of −90 to −5 mV, the anionic fine particles have a high reactivity with the treatment liquid, so that a high-quality printed matter can be obtained. .
The recording liquid contains a base, and the recording liquid is made basic with a pH of 7 to 12 to ensure the dispersion stability of components and color materials that are reactive with the components in the processing liquid contained in the recording liquid. Can do.
When the base dissociation constant pKa of the base is 5 or less, the dispersion stability of the component having reactivity with the treatment liquid contained in the recording liquid can be enhanced.
A recorded matter obtained by reacting two liquids on a recording medium using an ink set in which any of the recording liquids of the present invention and any of the processing liquids is combined has high image quality. Furthermore, by setting the processing liquid to a surface tension lower than that of the recording liquid, the processing liquid spreads more widely than the recording liquid on the recording medium, so that feathering is less likely to occur. Further, when the difference in surface tension between the recording liquid and the processing liquid is 2 or more, the processing liquid spreads more widely than the recording liquid on the recording medium, and thus feathering is less likely to occur. Furthermore, when the difference in pH between the recording liquid and the processing liquid is set to 2 or more, a concentration gradient occurs when the two liquids come into contact with each other, and the pH change occurs more quickly, thereby shortening the reaction time. For this reason, feathering / color bleeding can be suppressed, and a higher quality printed matter can be obtained.
By setting the discharge amount M2 of the recording liquid and the discharge amount M1 of the processing liquid to 0.2 ≦ M1 / M2 ≦ 3.0, the balance of the reaction components is good and the number of unreacted reaction components is small. Create high-quality prints. Recorded matter obtained by reacting two liquids on a recording medium using an ink set in which the balance of the combined ink set is adjusted optimally by adjusting the properties and components of the recording liquid and processing liquid. become. An image recording apparatus using the image forming method using the processing liquid, the recording liquid, and the ink set in combination of the above-described formulation can produce a high-quality printed matter.
The printed matter printed by the image recording apparatus has an excellent image quality. Further, by storing the treatment liquid having the above formulation in the ink cartridge, the storage stability of the treatment liquid is ensured and the handling becomes easy. Furthermore, by storing the recording liquid having the above-described prescription in the ink cartridge, the recording liquid is ensured in storage stability and becomes easy to handle.

Hereinafter, the present invention will be described in detail.
(Processing liquid)
In the conventional image forming method in which two liquids are reacted on a recording medium, a recording liquid containing a colorant and a processing liquid are mixed and reacted. Therefore, a sufficient reaction does not occur until the two liquids are sufficiently mixed, and the colorant penetrates into the deep part of the recording medium during the mixing time, so that a printed matter with sufficient image quality cannot be obtained. Therefore, as a result of intensive studies, the present inventors reacted two liquids on a recording medium using an ink set that is highly reactive and in which the components of the recording liquid and the processing liquid are adjusted so as to form large aggregates. When the cross section of the printed material printed using the image forming method is observed, a multilayer mainly composed of the color material and the components in the recording liquid in the processing liquid and the reactive components aggregated and fixed on the recording medium. We found that the structure was observed. When using an image forming method that creates a multilayer structure in which the color material and most of the reaction components in the processing liquid do not mix, the color material is fixed at a high density near the surface of the recording medium. It was found that a high-quality printed material having a low back-through density and high saturation and no feathering and color bleeding could be obtained. The reason why such a multilayer structure can be formed is not clear, but is considered as follows. Process inference will be described below with reference to FIG. However, the present invention is not limited by these descriptions.

When using an ink set that is highly reactive and produces agglomerates with a large particle size, first, when the reaction component in the recording liquid and the reaction component in the processing liquid contact, It is believed that a thin layer of agglomerates is formed. At this time, if the particle size of the aggregate is large, the aggregate layer functions as a filter that prevents the penetration of a component having a large particle size such as an anionic coloring material in the recording liquid, and most of the component having a large particle size is a recording medium. It is considered that the surface layer of the recording medium cannot be penetrated to the deep part of the recording medium. In addition, the aggregated layer is considered to be a semipermeable membrane that can permeate water, ions, low molecular weight polyvalent metal salts, and the like. In this case, the reaction components in the treatment liquid are permeated from the recording liquid side. Or aggregates due to pH change, and further impedes the penetration of the colorant into the deep part of the recording medium. On the other hand, on the recording liquid side, the anionic coloring material reacts with ions that have permeated from the processing liquid side, and the aggregation of the coloring materials is considered to occur near the surface of the recording medium due to a decrease in dispersion stability due to pH change. It is done. As a result, since the coloring material stays near the surface, the printed matter has a high image density and a low see-through density. Furthermore, since the density of the color material near the surface of the recording medium is increased, the recording medium can be filled well, and a printed matter with high saturation can be created. In particular, the effect is great in printing on plain paper in which the difference between the saturation of the recording medium and the saturation of the color material is large.
At this time, most of the coloring materials and reaction components in the treatment liquid individually react with ions and salts, and are aggregated due to pH change, so that it is considered that a multilayer structure is formed. Since the coloring material also agglomerates and fixes, the printed matter is excellent in water resistance, light resistance and fixing property.

(Explanation of conceptual diagram when viewed microscopically)
The image forming process will be described with reference to the schematic diagram of FIG.
In the initial stage where the processing liquid and the recording liquid constituting the ink set of the present invention are in contact with each other, an aggregate layer is formed in the vicinity of both contact interfaces. When this layer is formed, most of the coloring material and fine particles in each droplet cannot move through the formed layer because of its large size. However, since the acid in the processing liquid and the base in the recording liquid are small in size, they can easily pass through the gaps between the aggregate layers and quickly diffuse through the aggregate layer. Due to the diffusion of these ions, the remaining fine particles and the color material are also neutralized and the surface potential is lowered, so that the dispersed state or the dissolved state is destroyed and all the fine particles and the color material are aggregated. Since these agglomeration processes are instantaneously completed by the diffusion of ions, the above-described image forming method according to the present invention completes the aggregation of the entire system before the coloring material flows. In this way, the color material and the recording liquid are substantially aggregated without being mixed to form an aggregate layer formed of the color material and an aggregate layer formed of the fine particles.

(Description of cross-sectional TEM image)
The cross section of the recorded material can be observed by cutting a solid black portion of the recorded material and photographing the cross section with a transmission electron microscope (TEM). Examples of cross-sectional TEM photographs are shown in FIGS.
FIG. 9A is a cross-sectional photograph of a recorded material by one-pass printing that scans the inkjet recording head once to form an image, and FIG. It is a cross-sectional photograph of the recorded matter by printing. As can be seen from either figure, striped shading appears. Further, by examining by elemental analysis (EDX), it is possible to specify that the dark portion is the treatment liquid layer (fine particle aggregation layer) and the light portion is the recording liquid layer (color material aggregation layer).

Furthermore, the following excellent effects can be obtained. That is, by using the processing liquid according to the present invention, excellent color development characteristics similar to those of ink-jet coated paper, and image areas with a large amount of ink applied such as a shadow portion or a solid portion, there are few white smears and color unevenness, Excellent color uniformity. Further, since the application amount of the cationic fine particles can be reduced, particularly when printing on plain paper, a good image excellent in scratch resistance of the printed portion can be obtained without impairing the texture of the paper.
In addition, when the recording liquid and the processing liquid penetrate into the recording material, the aggregates of the coloring material are trapped in the porous portion of the recording medium, making it difficult for the coloring material to move, effectively preventing feathering and color bleeding. Can be prevented. Further, the glossiness of the printed matter made by reacting with the recording liquid can be increased due to the high glossiness of the fine particles themselves. In addition, since the agglomerated layer is a semipermeable membrane, the vehicle is considered to penetrate the recording material quickly, and in addition to good feathering and color bleeding, the drying property is good and the recording medium is difficult to swell. Become.
In addition, since the seepage of ink to the back side of the recording material is suppressed, double-sided printing can be performed satisfactorily.
It is considered that a recorded matter having higher print quality than that of the conventional one could be obtained by the above operation.

(surface tension)
As a result of studying a method for obtaining a high-quality printed matter in an image forming method for performing an image forming method in which such two liquids are reacted on a recording medium, the surface tension range of a suitable processing liquid is 10 It was found that ≦ γ ≦ 60 [mN / m], and a more preferable range was 10 ≦ γ ≦ 40 [mN / m].
Furthermore, it has been discovered that sufficiently high-quality printed matter can be obtained by using a treatment liquid having a low surface tension such that the surface tension γ of the treatment liquid is in the range of 10 ≦ γ ≦ 35. Further, it was found that a more preferable range is 10 ≦ γ ≦ 30 [mN / m], and a more preferable range is 10 ≦ γ ≦ 25 [mN / m].
However, if the surface tension γ1 of the treatment liquid is less than 15 [mN / m], the ejection stability is poor and a high-quality printed material can be produced. It is very difficult to obtain. Also, if it is less than 10 [mN / m], the discharge stability of the treatment liquid could not be ensured at all, and it was impossible to produce a complete printed matter in which all nozzles were stably discharged.
Since the treatment liquid having a lower surface tension has higher permeability, the treatment liquid can fill and cover the surface of the recording medium better. Therefore, when the recording liquid comes into contact with the processing liquid later, the aggregate due to the reaction covers the surface of the recording medium without gaps, and the recording liquid is less likely to penetrate into the recording medium from the gap where the processing liquid is not filled. For this reason, it is considered that the effect of increasing the image density, decreasing the back-through density, and increasing the saturation appears because the colorant hardly penetrates into the deep part of the recording medium. Furthermore, since the recording liquid is prevented from penetrating into the gaps where the processing liquid is not buried, it is considered that there is an effect of suppressing the occurrence of feathering and color bleeding.
Further, by reducing the surface tension of the processing liquid, the surface of the recording medium can be sufficiently filled with a smaller amount, so that a necessary discharge amount of the processing liquid can be suppressed. Therefore, since the total adhesion amount of the processing liquid and the recording liquid can be suppressed, the problem of cockling due to the swelling of the recording medium can be suppressed.
The surface tension of the present invention is a value measured by the Wilhelmi (plate) method using CBVP-Z (manufactured by Kyowa Interface Science Co., Ltd.), but is not limited to this measurement method.

(Defoamer)
However, although the present inventors have succeeded in obtaining a print with higher image quality by setting the processing liquid to a low surface tension, the processing liquid has a low surface tension. The non-ejection of the processing liquid as a cause frequently occurred, and it was impossible to obtain a stable and high-quality printed matter. Therefore, as a result of earnest examination of a method that can be obtained more stably, by adding 0.001 wt% to 10 wt%, which is an appropriate amount of an antifoaming agent, to the processing liquid, a high-quality printed matter even with a processing liquid with a low surface tension. It was discovered that it can be obtained stably. If it is less than 0.001 wt%, the defoaming effect is small and the treatment liquid tends to foam, so that air easily enters the head and non-ejection tends to occur. On the other hand, if it is 10 wt% or more, the ink head is likely to be clogged by the defoaming agent component, so that ejection stability cannot be obtained.

In JP 2001-301309 A, JP 2001-310545 A, and JP 2002-172847 A, an antifoaming agent can be added to the treatment liquid when the aggregation component contained in the treatment liquid is a polyvalent metal salt. However, no quantitative discussion has been made in combination with low surface tension. In addition, when the aggregation component contained in the treatment liquid is fine particles, the addition of an antifoaming agent to the treatment liquid is not discussed.
In particular, in the treatment liquid containing fine particles, it is preferable to contain a surfactant in order to ensure dispersion stability of the fine particles.

  The antifoaming agent must be dispersible in the solvent of the treatment liquid. Further, it is preferably insoluble in the solvent, and is preferably a dispersion. The dispersion may be inorganic fine particles, organic fine particles, or organic-inorganic composite fine particles. The antifoaming agent is preferably of the same polarity or nonionic with respect to the component reacting with the component in the recording liquid in the processing liquid.

As the antifoaming agent used in the present invention, a silicon-based antifoaming agent is preferably used.
In general, there are oil type, compound type, self-emulsification type, emulsion type, etc. for silicone antifoaming agent, but considering the use in water system, use of self-emulsification type or emulsion type ensures reliability. This is desirable. Further, modified silicon-based antifoaming agents such as amino-modified, carbinol-modified, methacryl-modified, polyether-modified, alkyl-modified, higher fatty acid ester-modified, alkylene oxide-modified, etc. may be used.

Commercially available silicone-based antifoaming agents include silicone antifoaming agents from Shin-Etsu Chemical Co., Ltd. (KS508, KS531, KM72, KM85, etc.), silicone antifoaming agents from Toray Dow Corning Co., Ltd. (Q2-3183A, SH5510, etc.), Nippon Unicar Co., Ltd. silicone antifoaming agent (SAG30 etc.), Asahi Denka Kogyo Co., Ltd. antifoaming agent (Adecanol series), and the like.
The amount of these antifoaming agents added to the recording liquid may be the minimum amount that is effective. If it is 0.001 mass%-10 mass%, sufficiently high quality printed matter can be stably obtained. In general, the range of 0.001% to 3% by mass is desirable, and the range of 0.005% to 0.5% by mass is more preferable.
The particle size of the antifoaming agent is desirably in the range of 0.01 to 1.0 μm. If it is 0.01 μm or less, a sufficient defoaming effect cannot be obtained, and if it is 1.0 μm or more, ejection stability is hindered.

(Aggregating component)
Examples of components having reactivity with the aggregating component in the recording liquid that can be contained in the processing liquid used in the image forming method of the present invention are as follows.
In the present invention, the component that reacts with the component in the recording liquid contained in the processing liquid may be an inorganic substance, an organic substance, or an organic-inorganic composite. A polyvalent metal salt or fine particles may be used, and even a monomer or polymer resin has an advantage over the prior art.

(Polyvalent metal salt)
You may use a polyvalent metal salt as a cation compound which can be added to the process liquid in this invention. The polyvalent metal salt is composed of a divalent or higher polyvalent metal ion and an anion that binds to the polyvalent metal ion. The polyvalent metal salt may be either an inorganic metal salt or an organic metal salt.
Specific examples of the polyvalent metal ions include divalent metal ions such as Ca ²⁺ , Cu ²⁺ , Ni ²⁺ , Mg ²⁺ , Zn ²⁺ and Ba ²⁺ , and trivalent metal ions such as Al ³⁺ , Fe ³⁺ and Cr ^3+. It is done. Examples of the anion include Cl ⁻ , NO ₃ ⁻ , I ⁻ , Br ⁻ , and CH ₃ COO ⁻ .
Examples of the inorganic metal salt include alkaline earth metal salts, and examples of the organic metal salt include aldonic acid salts, alkyl acid salts, and polyvalent metal salts of polyol phosphates. Is not this limit

(polymer)
Examples of reactive polymers include cationic polymers such as polyallylamine, polyvinylamine, polyimine, polyvinylpyrrolidone, polyethyleneimine, polyvinylpyridine, aminoacetalized polyvinyl alcohol, ionene polymer, polyvinylimidazole, polyvinylbenzylphosphonium, polyalkylallyl. Examples include cationic polymer compounds such as ammonium, polyamidine, polyamine sulfone, and cationic starch.

(monomer)
As an example of the monomer having reactivity with the coloring material, a higher alkylamine, a higher alkylammonium compound or a polyvalent amine compound may be used as the cationic compound.
It is also possible to use a mixture with the above cationic polymer compound.

  Examples of higher alkylamines or higher alkylammonium compounds that can be used in the present invention as components include laurylamine, stearylamine, cetylamine, behenylamine, dimethylstearylamine, lauryltrimethylammonium, cetyltrimethylammonium, stearyltrimethylammonium, behenyltrimethyl. Specific examples include ammonium, dioctyldimethylammonium, distearyldimethylammonium, stearyldimethylbenzylammonium, and the like. These ethylene oxide adducts may also be used.

  Specific examples of polyvalent amine compounds that can be used in the present invention include ethylenediamine, hexamethylenetetramine, piperazine, hexamethyleneimine, hexamethylenediamine, diethylenetriamine, tetraethylenepentamine, heptaethyleneoctamine, nanoethylenedecamine, Triethylenetetramine, triethylene-bis (trimethylene) hexamine, bis (3-aminoethyl) aminemethylenediamine, N, N′-bis- (3-aminopropyl) putrescine, 1,4-diazacycloheptane, 1, 5-diazacyclooctane, 1,4,11,14-tetraazatocloeicosane, 1,2-diaminopropan-3-ol, phenylenediamine, triaminobenzene, tetraaminobenzene, pentaaminobenzene, etc. It is possible.

(Fine particles)
Fine particles may be mentioned as a component having reactivity with the aggregating component in the recording liquid that can be contained in the processing liquid of the present invention. The fine particles may be inorganic, organic, or an organic-inorganic composite material. Polystyrene, styrene-acrylic copolymer, polymethyl methacrylate, melamine resin, epoxy resin, silicone resin, benzoguanamine resin, polyamide resin, fluorine resin, α, β-unsaturated ethylenic monomer can be obtained by emulsion polymerization, etc. A polymer etc. are mentioned.
The inorganic fine particles are roughly classified into inorganic salts such as calcium carbonate and inorganic oxides such as silica (SiO ₂ ).
Specific examples of the inorganic salt include, but are not limited to, calcium carbonate, calcium nitrate, calcium chloride, calcium sulfate, aluminum nitrate, aluminum chloride, aluminum sulfate, and iron sulfate. When used as an aqueous treatment solution, it is preferable to use a solution having low solubility in water such as calcium carbonate, calcium nitrate, iron sulfate, etc., because a dispersion can be easily obtained. Moreover, these can further improve the adsorbing ability and the aggregating ability of the coloring material by cationization treatment, and are more preferable. A method of modifying with a cationic agent has been proposed in the prior art (see JP-A-10-129113 and JP-A-11-20301).
In particular, among inorganic fine particles, an inorganic oxide has an isoelectric point, and thus is preferable as a component contained in the treatment liquid.
Specific examples of the inorganic oxide include, but are not limited to, silica (SiO ₂ ), cationized silica, titanium dioxide, alumina (Al ₂ O ₃ ), zirconia, and the like.

  Among inorganic oxides, cationic silica is particularly preferable in terms of reactivity. Cationic silica can be used as long as the surface of silica is cationized. To cationize, a cationic compound may be introduced chemically and physically on the silica surface. For example, the surface treatment can be chemically performed by coupling an amino compound to a silanol group of silica or reacting an aluminum compound. Further, the surface treatment can be physically carried out by mixing silica and a cationic compound in a solvent, physically adsorbing the cationic compound, and then removing the solvent. At that time, specific examples of the anionic silica used as the core material include ST-ZL, ST-20, ST-30, ST-40, ST-C, ST-N, ST-O, ST-S, ST-. 50, ST-20L, ST-OL, ST-XS, ST-YL, ST-XL, ST-UP, ST-OUP (manufactured by Nissan Chemical Co., Ltd.), Catalyst SI-350, SI-500 (manufactured by DuPont) ), Nipgel AY-220, AY-420, AY-460 (above, made by Nippon Silica) and the like. Not only these methods but also any silica surface treated with a cationic surface can be suitably used.

  Inorganic oxides can also be obtained as products. Examples of the cationized product of silica include ST-AK (manufactured by Nissan Chemical Co., Ltd.). Examples of alumina include alumina sol 100, 200, 520 (manufactured by Nissan Chemical Co., Ltd.). Titanium series (made by Idemitsu Kosan) is mentioned as titanium dioxide. Some of these fine particles are already available as aqueous dispersions.

The treatment liquid of the present invention may contain cationic inorganic / organic composite fine particles, and any particulate inorganic inorganic / organic composite particles can be used.
The cationic inorganic organic composite fine particles can be obtained by adsorbing a cationic organic compound on the surface of the inorganic fine particles, or conversely adsorbing a cationic inorganic compound on the surface of the organic compound. For example, inorganic / organic composite fine particles coated with a cationic polymer are prepared by dispersing inorganic fine particles in a solvent such as water and then adding the cationic polymer to water or a solution of a water-soluble organic solvent. It can be obtained by gradually adding.

  Specific examples of the cationic polymer include polyallylamine, polyvinylamine, polyimine, polyvinylpyrrolidone, polyethyleneimine, polyvinylpyridine, aminoacetalized polyvinyl alcohol, ionene polymer, polyvinylimidazole, polyvinylbenzylphosphonium, polyalkylallylammonium, and polyamidine. And cationic polymer compounds such as polyamine sulfone and cationic starch.

The amount of the component having reactivity with the coloring material is preferably more than 5 wt%, more preferably 15 wt% or more based on the treatment liquid. When the content is 5 wt% or less, the image quality improvement effect cannot be obtained sufficiently. A plurality of components may be used in combination. As the fine particles having reactivity with the coloring material, inorganic fine particles are particularly desirable. As the inorganic fine particles, the inorganic oxide has a particularly high reactivity with the color material, and higher image quality can be obtained in an ink set in which a treatment liquid using inorganic fine particles and a recording liquid are combined.
Moreover, the coagulation effect can be enhanced by adjusting the pH so that the inorganic oxide aggregates alone.

The average particle size of the component having reactivity with the colorant is preferably 500 nm or less, and more preferably 200 nm or less from the viewpoint of ejection stability. That is, if it exceeds 500 nm, the ejection head is likely to be clogged, and ejection failure is likely to occur.
The average particle diameter can be measured with an optical particle size distribution meter, and is represented by a particle diameter of 50%.

  A component having reactivity with the coloring material is dispersed in a vehicle containing water as a main component to form a treatment liquid. When the component having reactivity with the colorant is a fine particle, it is preferable to use a peptizer to stabilize the dispersion when the fine particle is dispersed. The peptizer forms an electric double layer on the surface of the chargeable particles, and the electric double layer is electrostatically repelled to prevent the particles from approaching and stabilize the dispersion. Fine particles are positively charged from neutral to acidic, so acetic acid, nitric acid, hydrochloric acid, formic acid, lactic acid, zirconium compounds such as alkali metal salts and zirconium oxychloride hydrate, pyrophosphoric acid Sodium, sodium hexametaphosphate, taurine and the like are used as a peptizer, but the present invention is not limited to these.

The treatment liquid of the present invention can be produced by the following method.
When the component having reactivity with the coloring material is water-soluble, the treatment liquid may be prepared using a treatment liquid dissolved in a solvent containing water as a main component.
When the component having reactivity with the coloring material is fine particles, fine particles, water and a peptizer are mixed to prepare a dispersion. Add water-soluble solvent if necessary and peptize with peptizer. Examples of the peptizer used at this time include a high-speed high shear shearing peptizer, a dissolver, a colloid mill, a homogenizer, and an ultrasonic peptizer. K. Auto homomixer, T.M. K. A homomic line flow, an ultra homomixer, a NNK colloid mill, etc. are mentioned. The number of revolutions during peptization varies depending on the type and structure of the peptizer, but is preferably 500 to 10,000 rpm, and more preferably 2000 to 8000 rpm. The temperature during peptization is preferably 5 to 100 ° C. The peptization time varies depending on the type and structure of the peptizer, but is preferably 0.01 to 68 hours.
Among the inorganic fine particles described above, cationic colloidal silica is particularly desirable. This is because cationic colloidal silica has particularly high reactivity with a colorant among inorganic fine particles, and higher image quality can be obtained in an ink set in which a treatment liquid and a recording liquid using the same are combined.

(Surfactant)
The treatment liquid of the present invention can contain fine particles dispersed in the recording liquid and a surfactant. The surfactant has an action of reducing the surface tension, an action of increasing the dispersion stability of the component that reacts with the coloring material, and an action of increasing the reactivity when the two liquids come into contact. The surfactant desirably contained in the treatment liquid is a compound having a polarity opposite to that of the coloring material or a nonionic compound.
When the recording liquid is anionic, a cationic surfactant such as a quaternary ammonium salt, a pyridinium salt, or an imidazoline type compound may be used as the cationic compound. Specific examples include lauryltrimethylammonium chloride, lauryldimethylbenzylammonium chloride, benzyltributylammonium chloride, benzalkonium chloride, cetylpyridinium chloride, 2-heptadecenylhydroxyethylimidazoline, and the like.

Further, the penetrant is added for the purpose of improving the wettability between the treatment liquid and the recording material and adjusting the penetration speed. As the penetrant, those represented by the following formulas (I) to (IV) are preferable.
That is, a polyoxyethylene alkylphenyl ether surfactant of the following formula (I), an acetylene glycol surfactant of the formula (II), a polyoxyethylene alkyl ether surfactant of the following formula (III) and the formula (IV The polyoxyethylene polyoxypropylene alkyl ether surfactant of () can reduce the surface tension of the liquid, thereby improving wettability and increasing the penetration rate.

（Ｒは分岐していても良い炭素数６〜１４の炭化水素鎖、ｋ：５〜２０）

(R is an optionally branched hydrocarbon chain having 6 to 14 carbon atoms, k: 5 to 20)

（ｍ，ｎは０〜４０）

(M and n are 0 to 40)

（Ｒは分岐してもよい炭素数６〜１４の炭化水素鎖、ｎは１〜２０の数）

(R is a C6-C14 hydrocarbon chain which may be branched, n is a number of 1-20)

（Ｒは炭素数６〜１４の炭化水素鎖、ｍ，ｎは２０以下の数）

(R is a hydrocarbon chain having 6 to 14 carbon atoms, m and n are numbers of 20 or less)

  Other than the compounds of the above formulas (I) to (IV), for example, diethylene glycol monophenyl ether, ethylene glycol monophenyl ether, ethylene glycol monoallyl ether, diethylene glycol monophenyl ether, diethylene glycol monobutyl ether, propylene glycol monobutyl ether, tetraethylene glycol chlorophenyl Use alkyl and aryl ethers of polyhydric alcohols such as ethers, nonionic surfactants such as polyoxyethylene polyoxypropylene block copolymers, fluorine-based surfactants, lower alcohols such as ethanol and 2-propanol However, diethylene glycol monobutyl ether is particularly preferable.

When added to the treatment liquid, the surfactant is preferably charged with the same polarity as the component contained, and when a cationic colloidal silica having a high aggregating effect with the coloring material is employed as the fine particles, the cationic compound is desirable.
As a specific example, for example, a cationic surfactant such as a quaternary ammonium salt, a pyridinium salt, or an imidazoline type compound may be used as the cationic compound. Specific examples include lauryltrimethylammonium chloride, lauryldimethylbenzylammonium chloride, benzyltributylammonium chloride, benzalkonium chloride, cetylpyridinium chloride, 2-heptadecenylhydroxyethylimidazoline, and the like.
Moreover, a commercially available cation G50 (manufactured by Sanyo Kasei Co., Ltd.) or the like can also be used as the cationic surfactant.

Alternatively, it may be a cationically charged amphoteric surfactant. When this is used, the pH of the treatment solution must be lower than the isoelectric point of the double-sided active agent. Among these amphoteric surfactants, those having an isoelectric point in the vicinity of the pH of the mixed solution are particularly preferred because the dispersion stability of the fine particles is lowered when the mixed solution is used.
Specific examples of the amphoteric surfactant include amino acid type amphoteric surfactants, RNHCH ₂ —CH ₂ C00H type compounds, and betaine type compounds such as stearyldimethylbetaine and lauryldihydroxyethylbetaine. However, the double-sided activator that can be used in the present invention is not limited to these.
The cationic surfactant has an effect of improving the image quality by lowering the surface tension and increasing wettability with the recording material to form a fine particle layer quickly and aggregating the anionic coloring material.

The recording liquid that can be used in the ink set of the present invention will be described.
As the coloring material used in the recording liquid of the present invention, either a dye or a pigment can be used. However, when the fine particles are cationic, anionic dye or pigment is more electrically neutralized and aggregated. Therefore, it is preferable in terms of improving image quality. Also, it is preferable to use a pigment rather than a dye. That is, when the pigment in the dispersed state is electrically neutralized rather than the dye in the dissolved state, aggregation is more efficiently generated, and thus the effect of improving the image quality is high.

  Examples of the pigment used in the recording liquid used in the ink set of the present invention include azo, phthalocyanine, anthraquinone, quinacridone, dioxazine, indigo, thioindigo, perylene, isoindolenone, and aniline black as organic pigments. Azomethine, rhodamine B lake pigment, carbon black and the like, and inorganic pigments include iron oxide, titanium oxide, calcium carbonate, barium sulfate, aluminum hydroxide, barium yellow, bitumen, cadmium red, chrome yellow and metal powder. It is done.

  Examples of pigment dispersants having an anionic group include polyacrylic acid, polymethacrylic acid, styrene acrylic resin, styrene maleic acid resin, water-soluble vinyl naphthalene acrylic resin, water-soluble vinyl naphthalene maleic resin, β-naphthalene sulfonic acid formalin Examples include condensates, carboxymethylcellulose, starch glycolic acid, sodium alginate, pectinic acid, hyaluronic acid and the like. These anionic dispersants can be used in the acid form, but alkali metal salts such as sodium and potassium can also be used.

(PH)
The treatment liquid in the present invention desirably contains a cationic compound, and preferably has a pH of 2 to 7 in order to ensure sufficient dispersion stability of the cationic compound.

(Ζ potential)
[Cationic treatment solution]
Examples of the treatment liquid of the present invention include a treatment liquid containing fine particles having a cationic group on the surface and an acid, and the fine particles are stably dispersed. Examples of the cationic treatment liquid suitable in the present invention include those containing an acid and having a pH adjusted to 2 to 7, and those having a zeta potential of +5 to +90 mV.

(About pH and zeta potential)
Explaining the ζ potential (zeta potential) of the treatment liquid. Generally, in a system in which a solid is dispersed in a liquid, when there is a free charge on the surface of the solid phase, the liquid phase near the solid phase interface has an opposite charge. Appear to maintain electrical neutrality. This is called an electric double layer, and a potential difference caused by this electric double layer is called a ζ potential. When the ζ potential is positive, the surface of the microparticles is cationic, and when it is negative, it is anionic. Generally, the higher the absolute value, the stronger the electrostatic repulsive force acting between the fine particles, and it is said that the dispersibility is good, and at the same time, the ionicity of the fine particle surface is considered strong. That is, it can be said that the cationic fine particles have a stronger cationic property as the ζ potential is higher, and a stronger force to attract the anionic compound in the recording liquid.

In the present invention, as a result of examining the relationship between the ζ potential of the cationic processing liquid used for image formation and the image quality of the formed image, when a processing liquid having a ζ potential in the range of +5 to +90 mV is used. The present inventors have found that a colored portion formed on a recording medium exhibits particularly excellent coloring characteristics.
The reason is not clear, but the progress of aggregation is inferred as follows. However, the present invention is not based on the following reasoning.
Since fine particles having such zeta potential are moderately cationic, when the anionic compound in the recording liquid comes into contact with the cationic compound in the processing liquid, rapid aggregation occurs at the interface, and a thin layer of aggregates is formed. It is thought that it is formed. At this time, the agglomerated layer functions as a filter that prevents the penetration of an anionic compound having a large particle size such as an anionic coloring material in the recording liquid to some extent, and most of the anionic compound having a large particle size is a surface layer of the recording medium Therefore, it is considered that it cannot penetrate to the deep part of the recording medium. On the other hand, the agglomerated layer is also considered to be a semipermeable membrane that is permeable to water, ions, low molecular weight polyvalent metal salts, and the like, and the cationic fine particles react with ions and salts that have permeated the semipermeable membrane, pH The effect of aggregating due to the change and preventing the penetration of the coloring material into the deep part of the recording medium increases. As a result, since the coloring material remains on the surface, the printed matter has a high image density and a low strike-through density. Furthermore, since the density of the color material near the surface of the recording medium is increased, the recording medium can be filled well, and a printed matter with high saturation can be created. The effect is particularly great on plain paper in which the difference between the saturation of the recording medium and the saturation of the color material is large.
Thereafter, most of the coloring materials and cationic fine particles individually react with ions and salts, or aggregate due to changes in pH to form a multilayer structure. Since the coloring material also agglomerates and fixes, the printed matter is excellent in water resistance, light resistance and fixing property.

Furthermore, it is considered that the following excellent effects can be obtained. In other words, by using the cationic processing liquid according to the present invention, in the image area having excellent color development characteristics similar to those of coated paper for inkjet and a large amount of recording liquid applied such as a shadow part and a solid part, white fog and color unevenness are observed. And the color uniformity is excellent. In addition, the amount of cationic fine particles applied can be reduced because the coloring is extremely efficient compared to coated paper, so that especially when printing on plain paper, the texture of the paper is not impaired, and the rubbing resistance of the printed portion is not affected. Good images with excellent properties can be obtained.
If the ζ potential of the cationic fine particles that can be contained in the treatment liquid is less than +5 mV, the fine particles cannot obtain dispersion stability, and the reactivity with the anionic component is weak, so that a high-quality printed matter cannot be obtained. If it is greater than +90 mV, the dispersion stability is too high, and the reactivity of the aggregation of the fine particles alone when they come into contact with the recording liquid becomes weak, so that high image quality cannot be obtained.
As a more preferable zeta potential range, for example, when a treatment liquid containing cationic fine particles having a zeta potential in the range of +10 to +85 mV is used, the boundary between dots becomes difficult to notice when solid printing is performed. A good image with less stripe unevenness can be obtained. Furthermore, when a treatment liquid containing cationic fine particles having a zeta potential in the range of +15 to +65 mV is used, an image having extremely excellent color developability can be obtained regardless of the paper type.

The pH of the cationic treatment liquid according to the present invention is preferably in the range of 2 to 7 in the vicinity of 25 ° C. including acid, from the viewpoints of storage stability and adsorptivity of the anionic compound. By using a treatment liquid having such a pH range, a high-quality printed material could be created. The reason is not clear, but the progress of aggregation is inferred as follows. However, the present invention is not based on the following reasoning.
When such a treatment liquid having a pH in the range of 2 to 7 is used, the stability of the anionic compound at the interface can be remarkably lowered when it comes into contact with the anionic recording liquid, and a semipermeable membrane of an aggregated layer can be formed. Conceivable. Most colorants are blocked by the semipermeable membrane, stay on the relatively surface of the recording medium and do not penetrate deeper. Furthermore, it is considered that protons and metal ions in the treatment liquid can permeate the semipermeable membrane of the aggregation layer to aggregate the color material alone. As a result, since the color material can be present at a high density in the vicinity of the surface, the printed material has a high image density and a high back-through density. Furthermore, since the density of the color material near the surface of the recording medium is increased, the recording medium can be filled well, and a printed matter with high saturation can be created. The effect is particularly great on plain paper in which the difference between the saturation of the recording medium and the saturation of the color material is large.
Most of the coloring materials and cationic fine particles are considered to react with ions and salts individually, or aggregate together due to pH change to form a multilayer structure. Since the coloring material also agglomerates and fixes, the printed matter is excellent in water resistance, light resistance and fixing property.
Further, when the amount is within the above range, the dispersion state of the cationic fine particles becomes good, so that the storage stability of the treatment liquid and the discharge stability from the recording head can be maintained well.
A more preferable pH range is 3 to 6. In this range, corrosion of the recording head due to long-term storage can be extremely effectively prevented, and the scratch resistance of the printed portion is further improved.

(acid)
As described above, it is preferable that the treatment liquid of the present invention contains an acid and the pH is adjusted to 2 to 7. However, the acid as the second component is the surface of the cationic fine particles. By ionizing and increasing the surface potential, the dispersion stability of the fine particles in the liquid is improved, the adsorbability of the anionic compound (anionic coloring material) in the recording liquid is improved, and the viscosity of the processing liquid is adjusted. Fulfill. The acid suitably used in the present invention is not particularly limited as long as the desired pH, zeta potential, or fine particle dispersibility can be obtained in combination with the cationic fine particles used, and the inorganic acids listed below can be used. It can be freely selected from organic acids and the like.

  Specifically, examples of the inorganic acid include hydrochloric acid, sulfuric acid, sulfurous acid, nitric acid, nitrous acid, phosphoric acid, boric acid, and carbonic acid, and examples of the organic acid include carboxylic acid and sulfonic acid described below. And amino acids.

  Examples of the carboxylic acid include formic acid, acetic acid, chloroacetic acid, dichloroacetic acid, trichloroacetic acid, fluoroacetic acid, trimethylacetic acid, methoxyacetic acid, mercaptoacetic acid, glycolic acid, propionic acid, butyric acid, valeric acid, caproic acid, caprylic acid, and caprine. Acid, lauric acid, myristic acid, palmitic acid, stearic acid, oleic acid, linoleic acid, linolenic acid, cyclohexanecarboxylic acid, phenylacetic acid, benzoic acid, o-toluic acid, m-toluic acid, p-toluic acid, o- Chlorobenzoic acid, m-chlorobenzoic acid, p-chlorobenzoic acid, o-bromobenzoic acid, m-bromobenzoic acid, p-bromobenzoic acid, o-nitrobenzoic acid, m-nitrobenzoic acid, p-nitrobenzoic acid Acid, oxalic acid, malonic acid, succinic acid, glutaric acid, adipic acid, tartaric acid, maleic acid, fumaric acid Acid, citric acid, phthalic acid, isophthalic acid, terephthalic acid, salicylic acid, p-hydroxybenzoic acid, anthranilic acid, m-aminobenzoic acid, p-aminobenzoic acid, o-methoxybenzoic acid, m-methoxybenzoic acid, p -Methoxybenzoic acid and the like.

  Examples of the sulfonic acid include benzenesulfonic acid, methylbenzenesulfonic acid, ethylbenzenesulfonic acid, dodecylbenzenesulfonic acid, 2,4,6-trimethylbenzenesulfonic acid, 2,4-dimethylbenzenesulfonic acid, and 5-sulfone. Examples include salicylic acid, 1-sulfonaphthalene, 2-sulfonaphthalene, hexanesulfonic acid, octanesulfonic acid, and dodecanesulfonic acid.

  Examples of amino acids include glycine, alanine, valine, α-aminobutyric acid, γ-aminobutyric acid, β-alanine, taurine, serine, ε-amino-n-caproic acid, leucine, norleucine, and phenylalanine.

(Degree of dissociation pKa)
And in the processing liquid of this invention, these can be used 1 type or in mixture of 2 or more types. Among these, those having a primary dissociation constant pKa of 5 or less in acid water are particularly excellent in the dispersion stability of cationic fine particles and the adsorptivity of anionic compounds, and therefore can be suitably used. Specific examples include hydrochloric acid, nitric acid, sulfuric acid, phosphoric acid, acetic acid, formic acid, oxalic acid, lactic acid, citric acid, maleic acid, malonic acid and the like.

  In the treatment liquid of the present invention, the mixing ratio of the cationic fine particles (A) and the acid (B) in the treatment liquid is A: B = 200: 1 to 5: 1, more preferably 150: 1 to 8 on a mass basis. It is preferable that the ratio is within the range of 1: in order to improve the dispersion stability of the cationic fine particles and to improve the adsorptivity of the anionic compound to the fine particle surfaces.

(Other components)
Next, other components constituting the cationic treatment liquid will be specifically described. The cationic treatment liquid of the present invention comprises the above-mentioned cationic fine particles as an essential component, preferably contains an acid as described above, and usually contains water as a liquid medium, but further contains a water-soluble organic solvent and Other additives may be included.

(Other)
<Organic solvent>
Examples of the water-soluble organic solvent used in this case include amides such as dimethylformamide and dimethylacetamide, ketones such as acetone, ethers such as tetrahydrofuran and dioxane, polyalkylene glycols such as polyethylene glycol and polypropylene glycol, Alkylene glycols such as ethylene glycol, propylene glycol, butylene glycol, triethylene glycol, 1,2,6-hexanetriol, thiodiglycol, hexylene glycol, diethylene glycol, ethylene glycol methyl ether, diethylene glycol monomethyl ether, triethylene glycol monomethyl Lower alkyl ethers of polyhydric alcohols such as ether, ethanol, isopropyl alcohol, n-butyl alcohol Lumpur, other monohydric alcohols such as isobutyl alcohol, glycerin, N- methyl-2-pyrrolidone, 1,3-dimethyl - imidazolidinone, triethanolamine, sulfolane, dimethyl monkey Hoki side, and the like. Although there is no restriction | limiting in particular about content of the said water-soluble organic solvent, For example, 5 to 60% of the process liquid total mass, Furthermore, 5 to 40% is a suitable range.

<Others>
In addition to the above, the treatment liquid of the present invention may further include a viscosity adjuster, a pH adjuster, an antiseptic, an antifungal agent, various surfactants, an antioxidant, a rust inhibitor, and an evaporation accelerator, if necessary. In addition, additives such as a water-soluble cationic compound and a binder resin may be appropriately blended. The selection of the surfactant is particularly important in adjusting the permeability of the treatment liquid into the recording medium. The water-soluble cationic compound can be freely selected and added within a range that does not impair the effects of the present invention for the purpose of further imparting the cationic property of the treatment liquid.

  The binder resin can be used in combination as long as it does not impair the texture of the recording medium and the storage stability and ejection stability of the processing liquid for the purpose of further improving the scratch resistance of the cationic fine particles. It can be used by freely selecting from a conductive polymer, emulsion, latex and the like.

(viscosity)
(Surface tension of treatment liquid)
The treatment liquid of the present invention is more preferably colorless or white, but the color may be adjusted according to the color of the recording medium. Furthermore, the suitable viscosity of the above processing liquid is 1-30 mPa * s (cP). A more preferable range is 2 to 25 mPa · s, and a further preferable range is 3 to 20 mPa · s. The processing liquid having a low surface tension can obtain a high-quality printed product as the viscosity is increased to a certain level.
The cause is not clear, but it is considered as follows. However, the present invention is not based on the following reasoning.
It is considered that the permeation speed in the direction perpendicular to the recording medium is somewhat suppressed as the viscosity of the processing liquid increases to a certain extent. At this time, when the surface tension is low, it is considered that the liquid droplets are crushed and spread in the horizontal direction with respect to the recording medium in the vicinity of the surface of the recording medium. Accordingly, it is considered that the processed liquid can prevent the recording liquid from penetrating well, and thus a printed matter with higher image quality can be obtained.
On the other hand, if the viscosity is too high, it becomes difficult to ensure the discharge stability of the treatment liquid. Moreover, since the permeability of the treatment liquid is deteriorated and the filling is deteriorated, a high-quality printed matter cannot be obtained. Therefore, it is desirable that the viscosity be as low as possible so that the treatment liquid has at least a permeability higher than that of the recording liquid.

(Ink formulation)
(component)
In the present invention, the component that reacts with the component in the processing liquid contained in the recording liquid may be an inorganic substance, an organic substance, or an organic-inorganic composite. Fine particles may be used, and even monomers and polymer resins are superior to the prior art. The reverse polarity in the treatment liquid is desirable, and an anionic property is particularly desirable.
Moreover, in order to improve characteristics other than reaction, such as viscosity adjustment, pH adjustment, and surface tension adjustment, a nonionic compound can also be contained. Further, a color material may be used as a component that reacts with a component in the processing liquid contained in the recording liquid.

(Anionic polymer)
In the present invention, specific examples of the cationic polymer to which the recording liquid can be added include the following. Specific examples of the low molecular weight anionic substance having a molecular weight of 1000 or less, preferably 100 to 700 are listed below.
Sodium lauryl sulfosuccinate, disodium polyoxyethylene lauroyl ethanolamide ester sulfosuccinate, disodium polyoxyethylene alkylsulfosuccinate, carboxylated polyoxyethylene lauryl ether sodium salt, carboxylated polyoxyethylene lauryl ether sodium salt, carboxylated poly Oxyethylene tridecyl ether sodium salt, polyoxyethylene lauryl ether sodium sulfate, polyoxyethylene lauryl ether sulfuric acid triethanolamine, polyoxyethylene alkyl ether sodium sulfate, polyoxyethylene alkyl ether sodium sulfate, sodium alkyl sulfate, alkyl alkyl triethanol Examples include amines, but are not limited to these. There.
As mentioned above, although the example of the low molecular anionic compound was given, it cannot be overemphasized that the compound which can be used by this invention is not necessarily limited to these.

As another example, a monomer or oligomer of an anionic polymer component described later may be used.
Next, the action and effect of the anionic polymer material having a molecular weight distribution peak of 1500 or more and 10,000 or less in the present invention is as follows. As a second stage of the reaction between the treatment liquid and the ink, By adsorbing the aggregates in the molecules, the size of the aggregates of the dyes formed by the association is further increased to make it difficult to enter the gaps between the fibers of the recording paper. It is to achieve both printing quality and fixing property by soaking.

Specific examples of the anionic polymer suitably used in the present invention include alkali-soluble polymers described below.
Specifically, hydrophobic monomers such as styrene, styrene derivatives, vinyl naphthalene, vinyl naphthalene derivatives, alkyl esters of acrylic acid, alkyl esters of methacrylic acid, α, β-ethylenically unsaturated carboxylic acids and aliphatic alcohols thereof It is a copolymer composed of hydrophilic monomers such as esters, acrylic acid, methacrylic acid, maleic acid, itaconic acid, fumaric acid, and derivatives thereof, and salts thereof.
The copolymer may have any structure such as random, block, and graft.
Furthermore, other specific examples of the anionic polymer include, but are not limited to, polystyrene sulfonic acid and the like.
As another specific example, a compound obtained by copolymerizing a nonionic monomer and an anionic monomer may be used.
Furthermore, the above-described polymer substance and anionic polymer substance are satisfactory as long as they are water-soluble, but may be a dispersion such as latex or emulsion.

(Fine particles)
(Anionic fine particles)
Next, components constituting the recording liquid of the present invention will be described. In order to achieve the above-described effects, the anionic fine particles mentioned as the first component are preferably those in which the surfaces of the particles themselves exhibit anionic properties when dispersed in the treatment liquid. By making the surface anionic, the cationic component can be adsorbed on the particle surface when it comes into contact with the processing liquid, and the color material is prevented from penetrating excessively into the recording medium. An inkjet recording image can be obtained.

  On the other hand, when the surface of the fine particles is not anionic and exists separately from the water-soluble anionic compound in the treatment liquid, the colorant aggregates around the anionic compound, and the color Since the coloring property of the material itself is impaired, it becomes difficult to achieve the coloring property equivalent to the coated paper for inkjet. Therefore, the surface of the fine particles used in the treatment liquid of the present invention is required to be anionic, but of course not only fine particles that are essentially anionic, Even if the fine particles are conductive, they can be used as long as the surface is anionized by the treatment.

  The anionic fine particles preferably used in the present invention are sufficient to achieve the object of the present invention as long as pores are formed in an aggregate of these fine particles formed on the recording medium. There is no particular limitation on the material type of the fine particles. As specific examples, for example, anionized silica, titania, zirconia, boria, silica boria, ceria, magnesia, silica magnesia, calcium carbonate, magnesium carbonate, zinc oxide, and the like, and composite fine particles and organic Examples thereof include fine particles and inorganic / organic composite fine particles. And in the processing liquid of this invention, these can be used 1 type or in mixture of 2 or more types.

  In addition, the anionic fine particles used in the present invention are dynamic light scattering from the viewpoint of color development, color uniformity and storage stability of the recording liquid after printing, as in the case of the cationic fine particles described above. The average particle diameter measured by the method is preferably in the range of 0.005 to 1 μm. More preferably, the average particle diameter is in the range of 0.01 to 0.8 μm. When such fine particles are used, the scratch resistance and texture after printing on the recording medium are particularly preferable. More preferably, the average particle diameter is in the range of 0.03 to 0.3 μm, and such fine particles have fine pore agglomerates formed on the recording medium having a target pore radius region. It is preferable because it can be easily formed effectively.

(Pore properties and shape of anionic fine particles)
In addition, the above-mentioned anionic fine particles used in the present invention efficiently form pores of fine particle aggregates formed on the recording medium, and at the same time, efficiently adsorb the coloring material on the surface of the fine particles themselves. In addition, it is preferable that the maximum pore radius of the fine particles in the nitrogen adsorption / desorption method is 2 nm to 12 nm and the total pore volume is 0.3 ml / g or more. More preferably, the fine pores of the fine particle aggregate formed on the recording medium have a fine pore radius of 3 nm to 10 nm and a total pore volume of 0.3 ml / g or more. It is preferable because it is easily formed effectively in the hole radius region.

  If the BET specific surface area of the fine particles used in the present invention is in the range of 70 to 300 m 2 / g, the coloring material can be more effectively covered in a monomolecular state due to the sufficient adsorption point of the coloring material to the fine particle surface. It becomes easy to leave in the vicinity of the surface of the recording medium and contributes to the improvement of color development.

  The shape of the fine particles used in the present invention can be determined by dispersing fine particles in ion-exchanged water and dropping them on the collodion film to prepare a measurement sample and observing it with a transmission electron microscope. In the present invention, when the fine particle aggregate is formed on the recording medium, the fine particle shape is needle-shaped, flat plate-shaped, or spherical primary particles have a directivity in that pores are formed in the aggregate. Non-spherical shapes such as rods and necklaces forming connected secondary particles can be suitably used. According to the knowledge of the present inventors, the flat plate shape has better water dispersibility than the needle shape, and the pore volume is reduced because the orientation of the fine particles becomes random when the fine particle aggregate is formed. Since it becomes large, it is more preferable.

  The content of the anionic fine particles as described above in the treatment liquid may be determined as appropriate in accordance with the type of substance used, but should be in the range of 0.1 to 40% on a mass basis. Is a preferable range for achieving the object of the present invention, more preferably 1 to 30%, and further preferably 3 to 15%. Within such a range, an excellent color image can be stably obtained regardless of the paper type, and the storage stability and ejection stability of the processing liquid are particularly excellent.

(Ζ potential)
[Anionic treatment solution]
The recording liquid of the present invention may contain fine particles having an anionic group on the surface. The fine particles are stably dispersed, and further, those containing a base and having a pH adjusted to 7 to 12 and those having a zeta potential of −5 to −90 mV are preferred.

(About pH and zeta potential)
Here, the zeta potential of the treatment liquid will be described. First, the basic principle of zeta potential will be described. In general, in a system in which a solid is dispersed in a liquid, if there is a free charge on the surface of the solid phase, a charged layer with an opposite charge appears in the liquid phase near the solid phase interface to maintain electrical neutrality. . This is called an electric double layer, and a potential difference caused by this electric double layer is called a zeta potential. When the zeta potential is positive, the surface of the fine particles is cationic, and when it is negative, it is anionic. Generally, the higher the absolute value, the stronger the electrostatic repulsive force acting between the fine particles, and it is said that the dispersibility is good, and at the same time, the ionicity of the fine particle surface is considered strong. That is, it can be said that the anionic fine particles have a stronger anionic property as the zeta potential is lower, and a stronger force to attract the cationic compound in the treatment liquid.

As a result of intensive studies by the present inventors, when the zeta potential of the treatment liquid is in the range of −5 to −90 mV, the cationic compound (cationic color material) in the recording liquid is particularly effective on the surface of the anionic fine particles. It was found that it adsorbs well and exhibits particularly excellent color development characteristics on the recording medium.
The reason is not clear, but the progress of aggregation is inferred as follows. However, the present invention is not based on the following reasoning.
Since fine particles having such a ζ potential are moderately anionic, when the anionic compound in the recording liquid comes into contact with the cationic compound in the processing liquid, rapid aggregation occurs at the interface, and a thin layer of aggregates is formed. It is thought that it is formed. At this time, the agglomerated layer functions as a filter that prevents the penetration of an anionic compound having a large particle size such as an anionic coloring material in the recording liquid to some extent, and most of the anionic compound having a large particle size is a surface layer of the recording medium Therefore, it is considered that it cannot penetrate to the deep part of the recording medium. On the other hand, the agglomerated layer is considered to be a semipermeable membrane that can permeate water, ions, low molecular weight polyvalent metal salts, and the like, and the cationic fine particles react with ions and salts, or aggregate due to pH change. This prevents the penetration of the color material into the deep part of the recording medium. As a result, since the coloring material stays near the surface, the printed matter has a high image density and a low see-through density. Furthermore, since the density of the color material near the surface of the recording medium is increased, the recording medium can be filled well, and a printed matter with high saturation can be created. The effect is particularly great on plain paper in which the difference between the saturation of the recording medium and the saturation of the color material is large.
Most colorants, anionic fine particles, and cationic fine particles are considered to react with ions and salts that have individually permeated through the semipermeable membrane, or aggregate together due to pH change to form a multilayer structure. Since the coloring material also agglomerates and fixes, the printed matter is excellent in water resistance, light resistance and fixing property.

Furthermore, it is considered that the following excellent effects can be obtained.
That is, by using the recording liquid according to the present invention, excellent color development characteristics similar to those of ink-jet coated paper, and image areas with a large amount of ink applied such as a shadow portion or a solid portion, there is little white smear or color unevenness, Excellent color uniformity. In addition, the amount of cationic fine particles applied can be reduced because the coloring is extremely efficient compared to coated paper, so that especially when printing on plain paper, the texture of the paper is not impaired, and the rubbing resistance of the printed portion is not affected. Good images with excellent properties can be obtained.
If the zeta potential of the anionic fine particles that can be contained in the recording liquid is greater than −5 mV, the anionic fine particles cannot obtain dispersion stability and the reactivity with the cationic component is weak, so that a high-quality printed matter cannot be obtained. If it is less than −90 mV, the dispersion stability is too high, and the reactivity of the aggregation of the fine particles alone when contacting with the treatment liquid is weak, so that high image quality cannot be obtained.
As a more preferable zeta potential range, for example, when a treatment liquid containing anionic fine particles having a zeta potential in the range of −10 to −85 mV is used, the boundary between dots becomes inconspicuous when solid printing is performed. As a result, a good image with less unevenness by head scanning can be obtained. Furthermore, when a treatment liquid containing anionic fine particles having a zeta potential in the range of −15 to −65 mV is used, an image having extremely excellent color developability can be obtained regardless of the paper type.

(PH)
The pH of the recording liquid according to the present invention is preferably in the range of 7 to 12 in the vicinity of 25 ° C., including the base, from the viewpoint of storage stability and cationic compound adsorption. By using a treatment liquid having such a pH range, a high-quality printed material could be created. The reason is not clear, but the progress of aggregation is inferred as follows. However, the present invention is not based on the following reasoning.
When such a recording liquid having a pH in the range of 7 to 12 is used, the stability of the cationic compound at the interface is remarkably lowered and the anionic compound and the cationic compound are adsorbed when contacting with the cationic processing liquid. It is thought that a semi-permeable membrane with a thin aggregated layer can be formed.
Most colorants are blocked by the semipermeable membrane and stay on the relatively surface of the recording medium and do not penetrate deeper. Furthermore, it is considered that bases such as hydroxide ions, anions, and low molecular weight salts in the recording liquid can permeate the semipermeable membrane of the aggregation layer and aggregate the cationic compound in the treatment liquid alone. As a result, the penetration of the coloring material is further prevented, and the coloring material can be present in the vicinity of the surface at a high density, resulting in a printed matter having a high image density and a high back-through density. Furthermore, since the density of the color material near the surface of the recording medium is increased, the recording medium can be filled well, and a printed matter with high saturation can be created. The effect is particularly great on plain paper in which the difference between the saturation of the recording medium and the saturation of the color material is large.
Most of the coloring materials and cationic fine particles are considered to react with ions and salts individually, or aggregate together due to pH change to form a multilayer structure. Since the coloring material also agglomerates and fixes, the printed matter is excellent in water resistance, light resistance and fixing property.
Further, when the content is within the above range, the dispersion state of the anionic fine particles becomes good, so that the storage stability of the treatment liquid and the discharge stability from the recording head can be maintained well.
A more preferable pH range is 8 to 11. In this range, corrosion of the recording head due to long-term storage can be extremely effectively prevented, and the scratch resistance of the printed portion is further improved.

(base)
As described above, it is preferable that the recording liquid of the present invention contains a base and the pH is adjusted to 7 to 12. However, the base as the second component has a surface of anionic fine particles. By ionizing and increasing the surface potential, the dispersion stability in the liquid is improved, and also the role of improving the adsorptivity of the anionic compound (anionic coloring material) in the recording liquid and adjusting the viscosity of the recording liquid. The base suitably used in the present invention is not particularly limited as long as desired properties such as pH, zeta potential and fine particle dispersibility can be obtained when combined with the anionic fine particles to be used. Any inorganic compound or organic compound can be freely selected and used.

  Specifically, for example, sodium hydroxide, lithium hydroxide, sodium carbonate, ammonium carbonate, ammonia, sodium acetate, ammonium acetate, morpholine, monoethanolamine, diethanolamine, triethanolamine, ethyl monoethanolamine, normal butyl monoethanol Alkanolamines such as amine, dimethylethanolamine, diethylethanolamine, ethyldiethanolamine, normal butyldiethanolamine, dinormalbutylethanolamine, monoisopropanolamine, diisopropanolamine, and triisopropanolamine can be used. Among these, a base having a primary dissociation constant pKb of 5 or less in water of base is particularly preferably used because it is particularly excellent in dispersion stability of anionic fine particles and adsorbability of a cationic compound (cationic coloring material). .

  The mixing ratio of the anionic fine particles (A) and the base (B) in the recording liquid of the present invention is A: B = 200: 1 to 5: 1, more preferably 150: 1 to 8: 1 on a mass basis. Within the range, the dispersion stability of the anionic fine particles and the adsorptivity of the cationic compound on the surface of the fine particles are preferable.

(Other components)
Next, other components constituting the recording liquid will be specifically described. The recording liquid of the present invention can contain the anionic fine particles described above. Preferably, it contains a base as described above, and usually contains water as a liquid medium, but further contains a water-soluble organic solvent and other additives such as an antifoaming agent, a viscosity adjusting agent, a pH adjusting agent, a preservative. In addition, additives such as various surfactants, antioxidants, evaporation accelerators, water-soluble anionic compounds and binder resins may be appropriately blended.

(viscosity)
(Surface tension of recording liquid)
The recording liquid of the present invention preferably has a surface tension of 10 to 60 mN / m (dyn / cm), more preferably 10 to 40 mN / m (dyn / cm), and a viscosity of the various properties of the recording liquid. 1 to 30 mPa · s (cP).

(Method for producing recording liquid)
The method for producing the recording liquid of the present invention containing the fine particles can be selected from methods generally used for dispersion. Specifically, in order to keep the average particle size and particle size distribution of the fine particles in the recording liquid within the above range, a disperser such as a roll mill, a sand mill, a homogenizer, an ultrasonic homogenizer, or an ultra-high pressure emulsifier (for example, trade name Nanomizer). Are preferably used for dispersion treatment, classification treatment by centrifugation, ultrafiltration, etc., and these treatment means can make the dispersed particle diameters of the fine particles in the recording liquid uniform.

(Coloring material)
<Colored ink>
[Anionic recording liquid]
Next, an aqueous anionic recording liquid constituting the ink set of the present invention in combination with the cationic processing liquid described above will be described. Here, the ink set refers to a combination of the treatment liquid of the present invention and a recording liquid containing an anionic substance (anionic color material).

  The anionic recording liquid used in the present invention uses a water-soluble dye containing an anionic group as a color material or a combination of an anionic compound when a pigment is used as a color material (this is also the present invention). Then, it is preferable to use an anionic coloring material. The above-mentioned anionic color material-containing ink used in the present invention further includes water, a water-soluble organic solvent and other components such as an antifoaming agent, a viscosity adjusting agent, a pH adjusting agent, and an antiseptic. In addition, a surfactant, an antioxidant and the like are included as necessary. Hereinafter, each component of these inks will be described.

(Water-soluble dye)
The water-soluble dye having an anionic group used in the present invention is not particularly limited as long as it is a water-soluble acid dye, a direct dye, or a reactive dye described in the Color Index. Further, even those not described in the color index are not particularly limited as long as they have an anionic group such as a sulfone group or a carboxyl group. Among the water-soluble dyes herein, those having a pH dependency of solubility are included.

(Pigment)
As another form of the aqueous anionic color material-containing ink, instead of the water-soluble dye having an anionic group as described above, a pigment and an anionic compound are used, and water, a water-soluble organic solvent, and other components, For example, the ink may contain a viscosity adjuster, a pH adjuster, a preservative, a surfactant, an antioxidant and the like as necessary. Here, the anionic compound may be a pigment dispersant, or when the pigment dispersant is not anionic, an anionic compound different from the dispersant may be added. Of course, even when the dispersant is an anionic compound, it may be further added with another anionic compound. In particular, when the dispersant is an anionic pigment, the recording liquid has high reactivity with the treatment liquid, and a printed matter with higher image quality can be obtained.

Although there is no limitation in particular in the pigment which can be used by this invention, For example, the pigment demonstrated below can be used conveniently. First, the carbon black used for the black pigment ink is carbon black produced by the furnace method or the channel method, the primary particle size is 15 to 40 mμm, the specific surface area by the BET method is 50 to 300 m ² / g, DBP oil absorption Those having an amount of 40 to 150 ml / 100 g, a volatile content of 0.5 to 10% by mass and a pH value of 2 to 9 are preferred.

  As such a thing, for example, no. 2300, no. 900, MCF88, No. 40, no. 52, MA7, MA8, no. 2200B (Mitsubishi Chemical), RAVEN1255 (Colombia), REGAL400R, REGAL660R, MOGUL L (above, Kibot), Color Black FW1, Color Black FW18, Color Black S170, Color Black S150, U As described above, commercially available products such as Degussa) can be used. Also, a new prototype for the present invention may be used.

  Examples of pigments used in yellow ink include C.I. I. Pigment Yellow 1, C.I. I. Pigment Yellow 2, C.I. I. Pigment Yellow 3, C.I. I. Pigment Yellow 13, C.I. I. Pigment Yellow 16, C.I. I. Pigment Yellow 83 and the like.

  Examples of pigments used as magenta ink include C.I. I. Pigment Red 5, C.I. I. Pigment Red 7, C.I. I. Pigment Red 12, C.I. I. Pigment Red 48 (Ca), C.I. I. Pigment Red 48 (Mn), C.I. I. Pigment Red 57 (Ca), C.I. I. Pigment Red 112, C.I. I. Pigment Red 122 and the like.

  Examples of pigments used as cyan ink include C.I. I. Pigment Blue 1, C.I. I. Pigment Blue 2, C.I. I. Pigment Blue 3, C.I. I. Pigment Blue 15: 3, C.I. I. Pigment Blue 16, C.I. I. Pigment Blue 22, C.I. I. Vat Blue 4, C.I. I. Vat Blue 6 etc. are mentioned. In addition, any of the above-described color materials that are newly produced for the present invention can be used.

(Self-dispersing pigment)
In addition, as a pigment that can be used for an anionic ink, a self-dispersing pigment that can be dispersed in water or an aqueous medium can be used without using a dispersant. Self-dispersing pigments are those in which at least one anionic hydrophilic group is bonded to the pigment surface directly or via another atomic group. Examples of the anionic hydrophilic group include those that are at least one selected from the hydrophilic groups listed below, and other atomic groups, an alkylene group having 1 to 12 carbon atoms, and a substituent. A phenylene group which may have a naphthyl group or a naphthylene group which may have a substituent may be mentioned.
_{-COOM, -SO 3 M, -SO 2} NH 2, -PO 3 HM, -PO 3 M 2
(M in the above formula represents a hydrogen atom, an alkali metal, ammonium, or organic ammonium.)

Since pigments anionically charged by introducing hydrophilic groups onto the pigment surface in this way have excellent water dispersibility due to repulsion of ions, a dispersing agent or the like is added even when incorporated in a colored ink. Even if not, a stable dispersion state is maintained. It is particularly preferable when the pigment is carbon black.
Further, as the water-soluble dye used in the present invention, those having excellent water resistance and light resistance among dyes classified as acidic dyes, direct dyes, basic dyes, reactive dyes, and food dyes in the color index are used. . These dyes may be used as a mixture of a plurality of types, or may be used as a mixture with other pigments such as pigments as necessary. These colorants are added within a range that does not impair the effects of the present invention.

(A) Acid dyes and food dyes C.I. I. Acid Yellow 17, 23, 42, 44, 79, 142
C. I. Acid Red 1, 8, 13, 14, 18, 26, 27, 35, 37, 42, 52, 82, 87, 89, 92, 97, 106, 111, 114, 115, 134, 186, 249, 254 289
C. I. Acid Blue 9, 29, 45, 92, 249
C. I. Acid Black 1, 2, 7, 24, 26, 94
C. I. Food Yellow 3, 4
C. I. Food Red 7, 9, 14
C. I. Food Black 1, 2

(B) As a direct dye C.I. I. Direct yellow 1, 12, 24, 26, 33, 44, 50, 86, 120, 132, 142, 144
C. I. Direct Red 1, 4, 9, 13, 17, 20, 28, 31, 39, 80, 81, 83, 89, 225, 227
C. I. Direct Orange 26, 29, 62, 102
C. I. Direct blue 1, 2, 6, 15, 22, 25, 71, 76, 79, 86, 87, 90, 98, 163, 165, 199, 202
C. I. Direct black 19, 22, 32, 38, 51, 56, 71, 74, 75, 77, 154, 168, 171

(C) As a basic dye C.I. I. Basic yellow 1, 2, 11, 13, 14, 15, 19, 21, 23, 24, 25, 28, 29, 32, 36, 40, 41, 45, 49, 51, 53, 63, 64, 65 67, 70, 73, 77, 87, 91
C. I. Basic Red 2, 12, 13, 14, 15, 18, 22, 23, 24, 27, 29, 35, 36, 38, 39, 46, 49, 51, 52, 54, 59, 68, 69, 70 73, 78, 82, 102, 104, 109, 112
C. I. Basic blue 1, 3, 5, 7, 9, 21, 22, 26, 35, 41, 45, 47, 54, 62, 65, 66, 67, 69, 75, 77, 78, 89, 92, 93 , 105, 117, 120, 122, 124, 129, 137, 141, 147, 155
C. I. Basic Black 2,8

(D) As a reactive dye, C.I. I. Reactive Black 3, 4, 7, 11, 12, 17
C. I. Reactive Yellow 1,5,11,13,14,20,21,22,25,40,47,51,55,65,67
C. I. Reactive Red 1, 14, 17, 25, 26, 32, 37, 44, 46, 55, 60, 66, 74, 79, 96, 97
C. I. Reactive blue 1, 2, 7, 14, 15, 23, 32, 35, 38, 41, 63, 80, 95, etc. can be used.

(Pigment dispersant)
As the pigment dispersant that can be used in the ink used in the present invention, any water-soluble resin having a function of stably dispersing the pigment in water or an aqueous medium due to the presence of an anionic group can be used. is there. In particular, those having a weight average molecular weight in the range of 1,000 to 30,000 are preferred. More preferably, it is the range of 3,000-15,000. Specifically, for example, styrene, styrene derivatives, vinyl naphthalene, vinyl naphthalene derivatives, hydrophobic monomers such as aliphatic alcohol esters of α, β-ethylenically unsaturated carboxylic acids, or acrylic acid, acrylic acid derivatives, Block copolymer, graft copolymer or random copolymer comprising two or more monomers selected from maleic acid, maleic acid derivatives, itaconic acid, itaconic acid derivatives, fumaric acid and fumaric acid derivatives, or these Examples include salts. These resins are alkali-soluble resins that are soluble in an aqueous solution in which a base is dissolved.

  Further, it may be a homopolymer composed of a hydrophilic monomer or a salt thereof. In addition, water-soluble resins such as polyvinyl alcohol, carboxymethyl cellulose, and naphthalene sulfonic acid formaldehyde condensate can also be used. However, the use of an alkali-soluble resin has the advantages that the viscosity of the dispersion can be reduced and the dispersion is easy. The water-soluble resin is preferably used in the range of 0.1 to 5% by mass with respect to the total amount of ink.

  The pigment ink that can be used in the present invention is constituted by dispersing or dissolving the above pigment and water-soluble resin in a water-soluble medium. A suitable aqueous medium in the pigment ink that can be used in the present invention is a mixed solvent of water and a water-soluble organic solvent. The water is not general water containing various ions but ion-exchanged water (deionized water). Is preferably used.

  When the dispersant is not an anionic polymer, it is preferable to add an anionic compound to the ink containing the pigment described above. Examples of the anionic compound preferably used in the present invention include a high molecular weight substance such as an alkali-soluble resin described in the section of the pigment dispersant and a low molecular weight anionic surfactant as described below. it can.

(Surfactant)
Specific examples of the low molecular weight anionic surfactant include, for example, disodium lauryl sulfosuccinate, disodium polyoxyethylene lauroyl ethanolamide ester sulfosuccinate, disodium polyoxyethylene alkylsulfosuccinate, carboxylated polyoxyethylene Lauryl ether sodium salt, carboxylated polyoxyethylene tridecyl ether sodium salt, polyoxyethylene lauryl ether sodium sulfate, polyoxyethylene lauryl ether sulfate triethanolamine, polyoxyethylene alkyl ether sodium sulfate, sodium alkyl sulfate, alkyl sulfate triethanol Although amine etc. are mentioned, it is not necessarily limited to these. A suitable use amount of the anionic substance as described above is in a range of 0.05 to 10% by mass, and more preferably 0.05 to 5% by mass with respect to the total amount of the ink.

  Further, a penetrant is added for the purpose of improving the wettability between the treatment liquid and the recording material and adjusting the penetration rate. As the penetrant, those represented by the following formulas (I) to (IV) are preferable. That is, a polyoxyethylene alkylphenyl ether surfactant of the following formula (I), an acetylene glycol surfactant of the formula (II), a polyoxyethylene alkyl ether surfactant of the following formula (III) and the formula (IV The polyoxyethylene polyoxypropylene alkyl ether-based surfactant (1) can reduce the surface tension of the liquid, so that the wettability can be improved and the penetration rate can be increased.

（Ｒは分岐していても良い炭素数６〜１４の炭化水素鎖、ｋ：５〜２０）

(R is an optionally branched hydrocarbon chain having 6 to 14 carbon atoms, k: 5 to 20)

（ｍ，ｎは０〜４０）

(M and n are 0 to 40)

（Ｒは分岐してもよい炭素数６〜１４の炭化水素鎖、ｎは１〜２０の数）

(R is a C6-C14 hydrocarbon chain which may be branched, n is a number of 1-20)

（Ｒは炭素数６〜１４の炭化水素鎖、ｍ，ｎは２０以下の数）

(R is a hydrocarbon chain having 6 to 14 carbon atoms, m and n are numbers of 20 or less)

  Other than the compounds of the above formulas (I) to (IV), for example, diethylene glycol monophenyl ether, ethylene glycol monophenyl ether, ethylene glycol monoallyl ether, diethylene glycol monophenyl ether, diethylene glycol monobutyl ether, propylene glycol monobutyl ether, tetraethylene glycol chlorophenyl Use alkyl and aryl ethers of polyhydric alcohols such as ethers, nonionic surfactants such as polyoxyethylene polyoxypropylene block copolymers, fluorine-based surfactants, lower alcohols such as ethanol and 2-propanol However, diethylene glycol monobutyl ether is particularly preferable.

Alternatively, an anionic amphoteric surfactant may be used. When this is used, the pH of the treatment solution must be lower than the isoelectric point of the double-sided active agent. Among these amphoteric surfactants, those having an isoelectric point in the vicinity of the pH of the mixed solution are particularly preferred because the dispersion stability of the fine particles is lowered when the mixed solution is used.
Specific examples of the amphoteric surfactant include amino acid type amphoteric surfactants, RNHCH ₂ —CH ₂ C00H type compounds, and betaine type compounds such as stearyldimethylbetaine and lauryldihydroxyethylbetaine. However, the double-sided activator that can be used in the present invention is not limited to these.

The recording liquid that can be used in the ink set of the present invention will be described.
As the coloring material used in the recording liquid of the present invention, either a dye or a pigment can be used. However, when the fine particles are cationic, anionic dye or pigment is more electrically neutralized and aggregated. Therefore, it is preferable in terms of improving image quality. Also, it is preferable to use a pigment rather than a dye. That is, when the pigment in the dispersed state is electrically neutralized rather than the dye in the dissolved state, aggregation is more efficiently generated, and thus the effect of improving the image quality is high.

  Examples of the pigment used in the recording liquid used in the ink set of the present invention include azo, phthalocyanine, anthraquinone, quinacridone, dioxazine, indigo, thioindigo, perylene, isoindolenone, and aniline black as organic pigments. Azomethine, rhodamine B lake pigment, carbon black and the like, and inorganic pigments include iron oxide, titanium oxide, calcium carbonate, barium sulfate, aluminum hydroxide, barium yellow, bitumen, cadmium red, chrome yellow and metal powder. It is done.

  Examples of pigment dispersants having an anionic group include polyacrylic acid, polymethacrylic acid, styrene acrylic resin, styrene maleic acid resin, water-soluble vinyl naphthalene acrylic resin, water-soluble vinyl naphthalene maleic resin, β-naphthalene sulfonic acid formalin Examples include condensates, carboxymethylcellulose, starch glycolic acid, sodium alginate, pectinic acid, hyaluronic acid and the like. These anionic dispersants can be used in the acid form, but alkali metal salts such as sodium and potassium can also be used.

(Other)
(Additional component in ink)
In addition to the above components, a surfactant, an antifoaming agent, a preservative, or the like can be added to the recording liquid in order to obtain a recording liquid having desired physical properties as required. A water-soluble dye or the like can also be added.

  Surfactants include anionic surfactants such as fatty acid salts, higher alcohol sulfates, liquid fatty oil sulfates, alkyl allyl sulfonates, polyoxyethylene alkyl ethers, polyoxyethylene alkyl esters, poly There are nonionic surfactants such as oxyethylene sorbitan alkyl esters, acetylene alcohol, and acetylene glycol, and one or more of these can be appropriately selected and used. The amount used varies depending on the amount of dispersant added, but is preferably 0.01 to 5% by mass relative to the total amount of ink. At this time, it is preferable to determine the amount of the activator added so that the surface tension of the ink is 30 mN / m (dyn / cm) or more. This is because, in the ink jet recording system used in the present invention, it is possible to effectively suppress the occurrence of printing misalignment (deviation of the landing point of ink droplets) due to wetting of the nozzle tip.

  As a method for producing a pigment ink as described above, first, after adding a pigment to an aqueous solution containing at least a pigment dispersion resin and water and stirring, the dispersion treatment is performed using a dispersion means described later, Centrifugation is performed as necessary to obtain a desired dispersion. Next, the above-described components may be further added to the dispersion and stirred to obtain ink.

  In addition, when an alkali-soluble resin is used, it is necessary to add a base in order to dissolve the resin. At this time, the amount of amine or base for dissolving the resin needs to be added at least 1 times the amount of amine or base determined by calculation from the acid value of the resin. The amount of amine or base can be calculated by the following formula.

  Further, if the premixing is performed for 30 minutes or more before the aqueous solution containing the pigment is dispersed, the pigment dispersion efficiency is improved. This premixing operation improves the wettability of the pigment surface and promotes the adsorption of the dispersant to the pigment surface.

  Examples of bases added to the dispersion when an alkali-soluble resin is used include, for example, organic amines such as monoethanolamine, diethanolamine, triethanolamine, aminemethylpropanol, and ammonia, or potassium hydroxide and sodium hydroxide. It is preferable to use an inorganic base such as

  On the other hand, the disperser used for preparing the pigment ink may be any disperser that is generally used, and examples thereof include a ball mill and a sand mill. Among these, a high speed type sand mill is preferable, and examples thereof include a super mill, a sand grinder, a bead mill, an agitator mill, a glen mill, a dinol mill, a pearl mill, and a cobol mill (all are trade names).

(Organic solvent)
In addition to the above-described components, the ink used in the present invention may contain a water-soluble organic solvent, a surfactant, a pH adjuster, a rust inhibitor, an antifungal agent, an antioxidant, an evaporation accelerator, a chelate as necessary. You may add additives, such as an agent and a water-soluble polymer.

  The liquid medium for dissolving or dispersing the colorant that can be used in the present invention is preferably a mixture of water and a water-soluble organic solvent. Specific examples of the water-soluble organic solvent include alkyl alcohols having 1 to 4 carbon atoms such as methyl alcohol, ethyl alcohol, n-propyl alcohol, isopropyl alcohol, n-butyl alcohol, sec-butyl alcohol, tert-butyl alcohol and the like. Amides such as dimethylformamide and dimethylacetamide, ketones such as acetone, ethers such as tetrahydrofuran and dioxane, polyalkylene glycols such as polyethylene glycol and polypropylene glycolicol, ethylene glycol, propylene glycol, butylene glycol, An alkylene group containing 2 to 6 carbon atoms, such as ethylene glycol, 1,2,6-hexanetriol, thiodiglycol, hexylene glycol, and diethylene glycol; Lower alkyl ethers of polyhydric alcohols such as xylene glycols, glycerin, ethylene glycol monomethyl (or ethyl) ether, diethylene glycol monomethyl (or ethyl) ether, N-methyl-2-pyrrolidone, 1,3-dimethyl-2-imidazo Examples thereof include cyclic amide compounds such as lysinone, sulfolane, dimethyl sulfoxide, 2-pyrrolidone and ε-caprolactam, and imide compounds such as succinimide.

  In general, the content of the water-soluble organic solvent is preferably 1% to 40%, more preferably 3% to 30% with respect to the total mass of the ink. Further, when the content of water in the ink is in the range of 30 to 95% by mass, the solubility of the coloring material is good, the viscosity of the ink can be suppressed, and the fixing property is sufficient. Can be satisfied.

  The anionic color material-containing ink used in the present invention can be used as an ink for a general water-based writing instrument, but is particularly suitable for application to an ink jet recording method in which ink is ejected due to an ink bubbling phenomenon caused by thermal energy. Therefore, the discharge is extremely stable and the generation of satellite dots or the like does not occur. However, in this case, thermal physical property values (for example, specific heat, thermal expansion coefficient, thermal conductivity) may be adjusted.

(Cationic ink)
[Cationic colorant-containing treatment solution]
Next, an aqueous cationic color material-containing treatment liquid that constitutes the ink set of the present invention in combination with the recording liquid described above will be described. The cationic color material-containing treatment liquid here is a treatment liquid in which a cationic color material is contained in the treatment liquid of the present invention. In the present invention, a cationic colorant-containing treatment liquid can also be included in the treatment liquid. In addition, the ink set in the present invention may be an ink set of a combination of a recording liquid and a processing liquid, an ink set of a combination of a recording liquid and a cationic colorant-containing processing liquid, or a recording liquid The ink set may be a combination of three or more kinds of liquid compositions of a treatment liquid and a cationic colorant-containing treatment liquid.

  The cationic colorant-containing treatment liquid used in the present invention uses a water-soluble dye containing a cationic group as a colorant, or a combination of a cationic compound when a pigment is used as a colorant ( In the present invention, this combination is also called a cationic colorant. The ink used in the present invention further includes water, a water-soluble organic solvent and other components such as an antifoaming agent, a viscosity adjusting agent, a pH adjusting agent, a preservative, a surfactant, An antioxidant or the like is included as necessary. Hereinafter, each component of the cationic colorant-containing treatment liquid will be described.

(Water-soluble dye)
The water-soluble dye having a cationic group used in the present invention is not particularly limited as long as it is a water-soluble dye described in, for example, a color index. Moreover, even if there is no description in the color index, there is no particular limitation as long as it has a cationic group. The water-soluble dyes herein include those having solubility-dependent pH.

(Pigment)
As another form of the cationic colorant-containing treatment liquid used in the present invention, a pigment and a cationic compound are used in place of the above-described water-soluble dye having a cationic group. It may be a cationic colorant-containing treatment liquid containing a component, for example, a viscosity modifier, a pH adjuster, a preservative, a surfactant, or an antioxidant as necessary. Here, the cationic compound may be a pigment dispersant, or when the pigment dispersant is not cationic, a cationic compound different from the dispersant may be added. Of course, even when the dispersant is a cationic compound, another cationic compound may be further added. The pigment that can be used in the present invention is not particularly limited, and the pigment described in the section of the anionic colorant-containing ink can be suitably used.

(Pigment dispersant)
As the dispersant for the pigment in the treatment solution containing a cationic colorant used in the present invention, any water-soluble resin having a function of stably dispersing the pigment in water or an aqueous medium due to the presence of the cationic group can be used. It is. As a specific example, what is necessary is just what is obtained by superposition | polymerization of a vinyl monomer, Comprising: At least one part of the polymer obtained has cationic property. Examples of the cationic monomer for constituting the cationic moiety include salts of tertiary amine monomers as described below and quaternized compounds thereof.

In particular,
N, N-dimethylaminoethyl methacrylate [CH ₂ ═C (CH ₃ ) —COO—C ₂ H ₄ N (CH ₃ ) ₂ ],
N, N-dimethylaminoethyl acrylate _{[CH 2 = CH-COO-} C 2 H 4 N (CH 3) 2],
N, N-dimethylaminopropyl methacrylate [CH ₂ ═C (CH ₃ ) —COO—C ₃ H ₆ N (CH ₃ ) ₂ ],
N, N-dimethylaminopropyl acrylate _{[CH 2 = CH-COO-} C 3 H 6 N (CH 3) 2],
N, N-dimethylacrylamide _{[CH 2 = CH-CON (} CH 3) 2],
N, N-dimethyl methacrylamide _{[CH 2 = C (CH 3} ) -CON (CH 3) 2],
N, N-dimethylaminoethyl acrylamide _{[CH 2 = CH-CONHC 2} H 4 N (CH 3) 2],
N, N-dimethylaminoethyl methacrylamide _{[CH 2 = C (CH 3} ) -CONHC 2 H 4 N (CH 3) 2],
N, N-dimethylaminopropyl acrylamide _{[CH 2 = CH-CONH-} C 3 H 6 N (CH 3) 2],
N, N-dimethylaminopropyl methacrylamide _{[CH 2 = C (CH 3} ) -CONH-C 3 H 6 N (CH 3) 2]
Etc.

  In the case of a tertiary amine, examples of the compound for forming a salt include hydrochloric acid, sulfuric acid, and acetic acid. Examples of the compound used for quaternization include methyl chloride, dimethyl sulfate, benzyl chloride, epichlorohydride. Phosphorus etc. are mentioned. Among these, methyl chloride, dimethyl sulfate and the like are preferable in preparing the dispersant used in the present invention. The salt of a tertiary amine or quaternary ammonium compound as described above behaves as a cation in water, and the acidity is a stable dissolution region under neutralized conditions. The content of these monomers in the copolymer is preferably in the range of 20 to 60% by mass.

  Examples of other monomers used in the composition of the polymer dispersant include 2-hydroxyethyl methacrylate, acrylic acid esters having a hydroxy group such as an acrylic acid ester having a long ethylene oxide chain in the side chain, and styrene monomers. Examples of the hydrophobic monomers and water-soluble monomers that can be dissolved in water near pH 7 include acrylamides, vinyl ethers, vinyl pyrrolidones, vinyl pyridines, and vinyl oxazolines. As the hydrophobic monomer, hydrophobic monomers such as styrene, styrene derivatives, vinyl naphthalene, vinyl naphthalene derivatives, alkyl esters of (meth) acrylic acid, acrylonitrile and the like are used. In the polymer dispersant obtained by copolymerization, the water-soluble monomer is used in the range of 15 to 35% by mass in order to make the copolymer exist stably in an aqueous solution, and the hydrophobic monomer is a pigment of the copolymer. In order to enhance the dispersion effect on the surface, it is preferably used in the range of 20 to 40% by mass.

(Self-dispersing pigment)
In the case of a cationically charged pigment, a hydrophilic group bonded directly or through another atomic group is bonded with at least one selected from quaternary ammonium groups listed below. However, the present invention is not limited to these.

In the above formula, R represents a linear or branched alkyl group having 1 to 12 carbon atoms, a substituted or unsubstituted phenyl group, or a substituted or unsubstituted naphthyl group. In the above cationic group, for example, NO ³⁻ and CH ₃ COO ⁻ are present as counter ions.

  As a method for producing a cationically charged self-dispersed pigment to which a hydrophilic group is bonded as described above, for example, a method for bonding an N-ethylpyridyl group having the structure shown below will be described as an example. And a method of treating the pigment with 3-amino-N-ethylpyridinium bromide.

  Since the pigment charged cationically by introducing a hydrophilic group to the pigment surface in this way has excellent water dispersibility due to repulsion of ions, even when it is contained in a cationic colorant-containing treatment liquid A stable dispersion state is maintained without adding a dispersant or the like. In particular, the pigment is preferably carbon black.

(viscosity)
(Surface tension of treatment liquid containing cationic colorant)
Furthermore, the cationic colorant-containing treatment liquid used in the present invention has a penetrability with the cationic colorant-containing treatment liquid of the recorded image when recorded on plain paper, etc. As the physical properties of the cationic colorant-containing treatment liquid itself, the surface tension at 25 ° C. is 10 to 60 mN / m (dyn / cm), preferably 10 [mN / m] ≦ γ ≦ 35 [mN / m], more preferably 10 [MN / m] ≦ γ ≦ 30 [mN / m], more preferably 10 [mN / m] ≦ γ ≦ 25 [mN / m]. The viscosity is preferably adjusted to 1 to 30 mPa · s (cP) or less, preferably 2 to 20 mPa · s (cP) or less, more preferably 3 to 15 mPa · s (cP).

<Coloring material concentration of cationic coloring material containing treatment liquid>
The mass concentration of the colorant component contained in the recording liquid and the colorant containing the cationic colorant-containing treatment liquid is appropriately selected according to the type of the colorant such as an aqueous dye, pigment, or self-dispersing pigment. However, the range of 0.1 to 20% by mass, particularly 0.1 to 12% by mass is preferable with respect to the mass of the liquid composition.

  Further, when the mass concentration of the color material component is in the range of 0.3 to 7%, the concentration of the reaction component with the recording liquid such as the cationic fine particles in the cationic color material-containing treatment liquid and the concentration of the cationic color material Regarding the relationship, when the color material is 1.2 or less, particularly 1.0 or less, with respect to the reaction component 1 with the recording liquid on a mass basis, it is formed under normal two-liquid recording conditions. The color developability of the image is particularly excellent.

The recording liquid and the cationic colorant-containing treatment liquid constituting the ink set according to the present invention are configured so that a reaction occurs when they come into contact with each other on the recording medium, thereby causing bleeding at the boundary between different color regions. Can be effectively relaxed. Here, the term “reaction” includes that the dissolved state or the dispersed state of the color material dissolved or dispersed in at least one liquid composition is destabilized by the contact of the two liquid compositions. ing. Then, as means for making the two liquid compositions reactive, for example, 1) adding a polyvalent metal salt to the recording liquid or the cationic colorant-containing treatment liquid;
2) A pH change is caused in the color mixture portion by contact between the recording liquid and the cationic color material-containing processing liquid. 3) The polarity is reversed between the recording liquid and the cationic color material-containing processing liquid.
And the like.

<Multivalent metal salt>
The polyvalent metal salt that can be preferably used in the present invention comprises a divalent or higher polyvalent metal ion and an anion as a counter ion of the polyvalent metal ion. Specific examples of the polyvalent metal ions include divalent metal ions such as Ca ²⁺ , Mg ²⁺ , Cu ²⁺ , Ni ²⁺ , and Zn ²⁺ , and trivalent metal ions such as Al ³⁺ and Fe ³⁺ . Examples of the counter ion (anion) include Cl ⁻ , NO ₃ ⁻ , SO ₄ ⁻ , CH ₃ COO ^{− and the} like. In particular, a metal salt composed of Ca ²⁺ or Mg ²⁺ is preferable because it has a high bleed suppressing effect.

  Specific examples of compounds that can be preferably used include magnesium acetate, calcium acetate, magnesium nitrate, calcium nitrate, magnesium phosphate, calcium phosphate, magnesium carbonate, calcium carbonate, magnesium oxalate, and calcium oxalate. Not limited. The concentration of these polyvalent metal salts in the colored cationic colorant-containing treatment solution may be appropriately determined within a range in which the effect of preventing printing quality and clogging is obtained, but is preferably about 0.1 to 20% by mass. More preferably, it is about 0.5 to 10% by mass. In addition, as the color material in the cationic color material-containing treatment liquid to which the polyvalent metal salt is added, a dye having excellent solubility, specifically, for example, a dye having two or more sulfone groups is used. It is preferable.

<PH adjuster>
Examples of pH adjusters used to suppress bleeding at the boundary of the colored cationic colorant-containing treatment solution include hydrochloric acid, acetic acid and carboxyl group-containing compounds, carbonic acid, sulfuric acid and sulfone group-containing compounds, nitric acid and phosphoric acid. Examples include compounds, acidic substances such as sulfurous acid and nitrous acid, and alkaline substances such as alkali metal hydroxides, alkaline earth metal hydroxides, alcohol amines, and ammonium salts.

<Method for forming a colored portion on a recording medium>
Next, a method for forming a colored portion on the recording medium of the present invention will be described. The method for forming a colored portion on a recording medium of the present invention includes (i) a step of applying an anionic or cationic colored cationic colorant-containing treatment liquid containing a coloring material to the recording medium, and (ii) A step of applying to the recording medium a liquid composition containing in a dispersed state fine particles whose surface is charged to a polarity opposite to that of the cationic colorant-containing treatment liquid, On the surface, the colored cationic colorant-containing treatment liquid and the liquid composition are applied so as to come into contact with each other in a liquid state. Hereinafter, a method for applying the liquid composition and the colored cationic colorant-containing treatment liquid configured as described above onto the recording medium will be described.

  The method for forming a colored portion on the recording medium of the present invention comprises the step (ii) of applying the liquid composition as described above onto the recording medium, and an anionic or cationic coloring including a coloring material. A step (i) of applying a cationic colorant-containing treatment liquid to a recording medium, in which case a colored portion forming region of the recording medium formed by the colored cationic colorant-containing treatment liquid containing the colorant Alternatively, the liquid composition is applied to the colored portion forming region and the vicinity thereof so that the colored cationic colorant-containing treatment liquid and the liquid composition are in contact with each other in a liquid state. The colored portion forming region here is a region where dots of the cationic color material-containing treatment liquid adhere, and the vicinity of the colored portion forming region is a region where dots of the cationic color material-containing treatment liquid adhere. It is a region that is about 1 to 5 dots away from the outside.

  In the method for forming a colored portion on the recording medium of the present invention, if the liquid composition of the present invention and the colored cationic colorant-containing treatment liquid come into contact with each other in a liquid state on the recording medium, these May be imparted by any method. Therefore, it does not matter whether the liquid composition or the cationic colorant-containing treatment liquid is applied to the recording medium first. For example, the process (i) may be performed after performing the process (ii), or the process (ii) may be performed after performing the process (i). It is also preferable to perform step (ii) after performing step (i) and then perform step (i) again.

  In addition, when the liquid composition is first applied to the recording medium, the time from when the liquid composition is applied to the recording medium to when the cationic colorant-containing treatment liquid is applied onto the recording medium Although there is no particular limitation, it is preferable to apply the cationic colorant-containing treatment liquid onto the recording medium almost simultaneously or within a few seconds in order to come into contact with each other in a liquid state.

(media)
(Recording medium)
The recording medium used in the above-described method for forming a colored portion on the recording medium of the present invention is not particularly limited, and so-called plain paper such as copy paper and bond paper, which has been conventionally used. Are preferably used. Of course, a coated paper specially prepared for inkjet recording and a transparent film for OHP are also preferably used. Furthermore, it can be suitably used for general high-quality paper and glossy paper.

(apparatus)
An ink jet recording method of the present invention and an image forming apparatus for carrying out the method will be described with reference to the drawings.
The image forming apparatus of FIG. 1 stores processing liquid and recording liquid in a cartridge (20), and supplies the processing liquid and recording liquid from the cartridge to the recording head. Here, the cartridge (20) is mounted in a state where the processing liquid and the recording liquid for each color are separated.

  The recording head is mounted on the carriage (18) and moved while being guided by the guide shafts (21) and (22) by the timing belt (23) driven by the main scanning motor (24). On the other hand, the recording material is placed at a position facing the recording head by the platen.

  An enlarged view of the nozzle face of the recording head is shown in FIG. A nozzle (31) for discharging the processing liquid is provided in the vertical direction, and yellow ink, magenta ink, cyan ink, and black recording liquid are respectively supplied from the nozzles (32), (33), (34), and (35). Discharged.

  Further, as shown in FIG. 3, in the recording head, all the nozzles can be arranged in the horizontal direction. In the figure, reference numerals (36) and (41) are discharge nozzles for the processing liquid, and yellow ink and magenta ink are respectively ejected from the nozzles (37), (38), (39), and (40). , Cyan ink, and black ink are ejected. In the recording head of this aspect, since the treatment liquid discharge nozzles are provided at the left and right ends, printing is possible both in the forward path and the backward path in which the recording head reciprocates on the carriage. That is, it is possible to attach the treatment liquid first and then attach the color ink on the forward path or the backward path, or vice versa, and an image density difference due to the difference in the moving direction of the recording head occurs. Absent.

The image forming apparatus of the present invention can be replenished with processing liquid and recording liquid by replacing the cartridge. Further, this cartridge may be integrated with the recording head.
4 and 5 show a cartridge capable of storing the processing liquid of the present invention and the recording liquid.
The cartridge shown in FIGS. 4 and 5 can store either processing liquid or recording liquid.
As for the range in which the recording liquid and the processing liquid are discharged and overlapped by each print head, it is most preferable that the recording liquid and the processing liquid overlap each other. However, the application of the present invention is not limited to this range. For example, the scope of the present invention also includes a case where the recording liquid is applied by thinning out the processing liquid and enlarged by bleeding or the like, or when the processing liquid is applied only to the contour portion of the image and a part of the recording liquid is superimposed include.

(Other)
In addition to the above, the recording liquid of the present invention may further include a viscosity adjuster, a pH adjuster, an antiseptic, an antifungal agent, various surfactants, an antioxidant, a rust inhibitor, and an evaporation accelerator, if necessary. Additives such as water-soluble anionic compounds and binder resins may be appropriately blended. The selection of the surfactant is particularly important in adjusting the permeability of the liquid composition to the recording medium. The water-soluble anionic compound can be freely selected and added within a range that does not impair the effects of the present invention for the purpose of further imparting the anionic property of the recording liquid.

  The binder resin can be used in combination as long as the texture of the recording medium, the storage stability of the recording liquid and the ejection stability are not impaired, for the purpose of further improving the scratch resistance of the anionic fine particles. It can be used by freely selecting from a conductive polymer, emulsion, latex and the like.

(Ink set)
(Aggregated form)
An ink set using the treatment liquid and the recording liquid is applied to the recording medium, and the processing liquid and the recording liquid are brought into contact with each other on the recording medium to react to form an image, thereby obtaining a high-quality image recorded matter. I was able to.
The reaction between the components and the color material and the effect thereof are considered as follows. However, the present invention is not limited by these descriptions.

The fine particles contained in the treatment liquid of the present invention have a charge on the particle surface, and the components are repelled by the surface charge, so the dispersion is stabilized. The fine particles have an isoelectric point. When a recording liquid containing a coloring material having a polarity opposite to that of the fine particles comes into contact with a processing liquid containing a component, the coloring material is strongly adsorbed to the fine particles by an electrical action. At this time, since the surface charge of the fine particles is neutralized by the charge of the color material, the repulsive action between the components disappears, and the fine particles and the color material form a large aggregate. In addition, since water-soluble groups such as carbonyl groups and sulfonyl groups of the coloring material are concealed by components during adsorption, the solubility of the aggregates in water rapidly decreases and the aggregates become even larger. Furthermore, by adjusting the pH of the mixed solution to be close to the pH that is the isoelectric point of the component contained in the processing solution, the fine particles are aggregated even by themselves, and the formation of such aggregates occurs rapidly. it is conceivable that.
In such an ink set in which the components of the recording liquid and the processing liquid are adjusted so that the aggregation proceeds extremely rapidly, the aggregation component is not limited to fine particles, but the anionic compound in the recording liquid and the processing liquid It is thought that when the cationic compound comes into contact, rapid aggregation occurs at the interface and a thin layer of aggregate is formed.
At this time, the agglomerated layer functions as a filter that prevents the penetration of an anionic compound having a large particle size such as an anionic coloring material in the recording liquid to some extent, and most of the anionic compound having a large particle size is a surface layer of the recording medium Therefore, it is considered that it cannot penetrate to the deep part of the recording medium. In addition, the aggregate layer is considered to be a semipermeable membrane that is permeable to water, ions, low molecular weight polyvalent metal salts, and the like, and the reaction components in the treatment liquid react with the ions and salts that have permeated from the recording liquid side. Or agglomerates due to pH change, and further prevents the penetration of the coloring material into the deep part of the recording medium. Furthermore, the surface of the recording medium is caused by a salting-out reaction of the anionic coloring material with the ions that have been transmitted from the processing liquid side or by aggregation of the coloring materials due to a decrease in dispersion stability due to pH change. It is considered to aggregate in the vicinity. As a result, since the coloring material stays near the surface, the printed matter has a high image density and a low see-through density. Furthermore, since the density of the color material near the surface of the recording medium is increased, the recording medium can be filled well, and a printed matter with high saturation can be created. The effect is particularly great on plain paper in which the difference between the saturation of the recording medium and the saturation of the color material is large.
Most of the coloring materials and cationic fine particles are considered to react with ions and salts individually, or aggregate together due to pH change to form a multilayer structure. Since the coloring material also agglomerates and fixes, the printed matter is excellent in water resistance, light resistance and fixing property.

Furthermore, it is considered that the following excellent effects can be obtained. That is, by using the cationic processing liquid according to the present invention, white coloring and color unevenness can be achieved in image areas having excellent color development characteristics similar to those of coated paper for ink-jet printing and a large amount of ink applied such as shadows and solids. Less color and excellent color uniformity. In addition, the amount of cationic fine particles applied can be reduced because the coloring is extremely efficient compared to coated paper, so that especially when printing on plain paper, the texture of the paper is not impaired, and the rubbing resistance of the printed portion is not affected. Good images with excellent properties can be obtained.
Further, when the recording liquid and the processing liquid permeate the recording material, the aggregates are trapped in the porous portion of the recording medium, and the coloring material becomes difficult to move, and feathering and color bleeding can be effectively prevented. Further, the glossiness of the printed matter made by reacting with the recording liquid can be increased due to the high glossiness of the fine particles themselves. In addition, the component and the color material form a particulate aggregate, and form a permeable film when stacked in the shape of a stone wall near the surface of the recording material. Therefore, since the vehicle quickly penetrates into the recording material, the color bleed is improved and the drying property is improved.
Further, since the ink oozes out to the back side of the recording material, double-sided printing can be performed satisfactorily.
Due to the above actions, a recorded matter having higher print quality than the conventional one can be obtained.

(Surface tension + antifoaming agent)
When using an ink set in a range where the surface tension γ of the treatment liquid is 10 ≦ γ ≦ 35, it is possible to produce a printed matter with particularly high image quality.
A more preferable range is 10 ≦ γ ≦ 30, and a more preferable range is 10 ≦ γ ≦ 25.
When such a low surface tension treatment liquid is used, it is indispensable for the production of a stable printed matter that the antifoaming agent is contained in an appropriate amount of 0.001 wt% to 10 wt%.

(Γ1 / γ2 ≦ 1)
Further, when the surface tension of the processing liquid is γ1 and the surface tension of the recording liquid is γ2, adjusting the surface tension so that γ1 / γ2 ≦ 1 has a high effect of reducing the feathering of the printed matter. This is probably because the processing liquid spreads wider than the recording liquid and suppresses the seepage of droplets.
Inference will be described with reference to FIG. 7 below regarding the mechanism for achieving high image quality by using low surface tension. However, the present invention is not based on the reasoning.

Step 1: When a high surface tension treatment liquid is used immediately after ink landing, the treatment liquid is poorly embedded in the recording medium, whereas the high viscosity low surface tension treatment liquid does not penetrate immediately due to high viscosity, and has a low surface tension. For this reason, the droplets are crushed and the surface is filled widely, and the filling is improved.
Step 2 to Step 3: Aggregation reaction to fixing When a high surface tension treatment solution is used, the penetration depth of the treatment solution becomes deep, so that a longer ion movement distance is required and the reaction takes time. During this time, the unreacted color material spreads and causes feathering, which causes color bleeding. In addition, the colorant penetrates from the portion where the recording medium is poorly filled into the recording medium, and the showthrough occurs.
On the other hand, in the treatment liquid with high viscosity and low surface tension, since the treatment liquid spreads widely, the penetration depth of the treatment liquid is shallow and the required ion movement distance is short, so that aggregation is considered to occur in a relatively short time. . For this reason, feathering and color bleeding are reduced. At the same time, it is considered that the surface tension of the ink is lowered. However, since the treatment liquid is well buried, it cannot penetrate into the inner side of the recording medium and spreads sideways, resulting in better filling of the colorant. For this reason, the image density is improved and the back-through density is reduced.

(PH)
Further, when the difference in pH between the treatment liquid and the recording liquid is 2 or more, a printed matter with higher image quality can be obtained. It is thought that the proton concentration gradient is sufficiently high when the two come into contact with each other, so that proton diffusion proceeds rapidly and the agglutination reaction proceeds more rapidly.
(Discharge rate)
It is desirable that M1 / M2 = 0.2 to 3.0, where M1 is the treatment liquid discharge amount and M2 is the recording liquid discharge amount. If it is smaller than 0.2, the discharge amount of the treatment liquid is not sufficient and the aggregation effect cannot be obtained. If it is greater than 3.0, if a sufficient amount of recording liquid is ejected, the total liquid volume becomes too large and the recording medium swells to cause cockling or feathering / color bleeding (ζ potential).
When the treatment liquid contains cationic fine particles, the contact between the treatment liquid and the recording liquid is such that the pH of the mixed liquid is close to the pH at which the cationic fine particles in the treatment liquid have an isoelectric point when contacted with the recording liquid. By adjusting the pH, a higher quality printed material can be obtained. A preferable range of the pH of the mixed solution is β−2 ≦ α ≦ β + 2 where α is the pH of the mixed solution and β is the pH at which the cationic fine particles have an isoelectric point. More preferably, β−1.5 ≦ α ≦ β + 1.5, and even more preferably β−1.0 ≦ α ≦ β + 1.0. The closer to the isoelectric point, the more effective the cationic fine particles are aggregated.
Further, by selecting a color material such that the pH and α of the mixed solution are such that the recording solution is agglomerated even when the recording solution is a single recording solution, a printed matter with higher image quality can be obtained.

Next, the present invention will be specifically described with reference to examples and comparative examples. However, parts and% are based on weight.
<Processing liquid A>
Cationic colloidal silica (ST-AK [Nissan Chemical Co., Ltd.]) 15.0 parts Glycerin 25.0 parts Olefin E1010 2.0 parts 2-Ethylhexanediol 1.0 part KM-72F (silicon-based antifoaming agent) [Shin-Etsu Chemical Co., Ltd.] 0.1 part Ion-exchanged water 56.9 parts
(Surface tension γ1 = 14.5)

<Processing liquid B>
Cationic colloidal silica (ST-AK [Nissan Chemical Co., Ltd.]) 15.0 parts Glycerin 25.0 parts Olefin STG [Shin-Etsu Chemical Co., Ltd.] 2.0 parts 2-ethylhexanediol 1.0 part KM-72F (Silicon-based antifoaming agent) [Shin-Etsu Chemical Co., Ltd.] 0.1 part Ion-exchanged water 56.9 parts
(Surface tension γ1 = 23.0)

<Processing liquid C>
Cationic colloidal silica (ST-AK [Nissan Chemical Co., Ltd.]) 15.0 parts Glycerin 25.0 parts Cationic surfactant (Cation G50 [Sanyo Kasei Co., Ltd.]) 2.0 parts 2-Ethylhexanediol 1.0 part KM-72F (silicon-based antifoaming agent) [Shin-Etsu Chemical Co., Ltd.] 0.1 part ion-exchanged water 56.9 parts
(Surface tension γ1 = 26.5)

<Processing liquid D>
Cationic colloidal silica (ST-AK [Nissan Chemical Co., Ltd.]) 15.0 parts Glycerin 25.0 parts Dispanol TOC [Nippon Yushi Co., Ltd.] 2.0 parts 2-Ethylhexanediol 1.0 part KM- 72F (silicon-based antifoaming agent) [Shin-Etsu Chemical Co., Ltd.] 0.1 part Ion-exchanged water 56.9 parts
(Surface tension γ1 = 32.0)

<Processing liquid E>
Cationic colloidal silica (ST-AK [Nissan Chemical Co., Ltd.]) 15.0 parts Glycerin 25.0 parts 2-Ethylhexanediol 1.0 part KM-72F (silicon-based antifoaming agent) [Shin-Etsu Chemical Co., Ltd.] ] 0.1 part Ion exchange water 58.9 parts
(Surface tension γ1 = 39.9)

<Processing liquid F>
Cationic colloidal silica (ST-AK [Nissan Chemical Co., Ltd.]) 15.0 parts Glycerin 25.0 parts KM-72F (silicon-based antifoaming agent) [Shin-Etsu Chemical Co., Ltd.] 0.1 parts Ion-exchanged water 59 .9 parts
(Surface tension γ1 = 41.0)

<Processing liquid G>
Cationic colloidal silica (ST-AK [Nissan Chemical Co., Ltd.]) 15.0 parts Glycerin 25.0 parts Olefin STG 2.0 parts 2-ethylhexanediol 1.0 part KM-72F (silicon-based antifoaming agent) [Shin-Etsu Chemical Co., Ltd.] 0.001 part Ion-exchanged water 56.999 parts

<Treatment liquid H>
Cationic colloidal silica (ST-AK [Nissan Chemical Co., Ltd.]) 15.0 parts Glycerin 25.0 parts Olefin STG 2.0 parts 2-ethylhexanediol 1.0 part KM-72F (silicon-based antifoaming agent) [Shin-Etsu Chemical Co., Ltd.] 10.0 parts Ion-exchanged water 47.0 parts

<Treatment liquid I>
Cationic colloidal silica (ST-AK [Nissan Chemical Co., Ltd.]) 15.0 parts Glycerin 25.0 parts Olefin STG 2.0 parts 2-ethylhexanediol 1.0 part Ion-exchanged water 57.0 parts

<Treatment liquid J>
Cationic colloidal silica (ST-AK [Nissan Chemical Co., Ltd.]) 15.0 parts Glycerin 25.0 parts Olefin STG 2.0 parts 2-ethylhexanediol 1.0 part KM-72F (silicon-based antifoaming agent) [Shin-Etsu Chemical Co., Ltd.] 13.0 parts Ion-exchanged water 47.0 parts

<Processing liquid K>
Polyacrylamide 15.0 parts Glycerin 25.0 parts Olefin STG 2.0 parts 2-Ethylhexanediol 1.0 part KM-72F (silicon-based antifoaming agent) [Shin-Etsu Chemical Co., Ltd.] 0.1 part Ion-exchanged water 56.9 parts

<Processing liquid L>
Ethylenediamine 15.0 parts Glycerin 25.0 parts Olefin STG 2.0 parts 2-Ethylhexanediol 1.0 part KM-72F (silicon-based antifoaming agent) [Shin-Etsu Chemical Co., Ltd.] 0.1 part Ion-exchanged water 56 .9 parts

<Processing liquid M>
Magnesium glycerophosphate 15.0 parts Glycerin 25.0 parts Olefin STG 2.0 parts 2-ethylhexanediol 1.0 part KM-72F (silicon-based antifoaming agent) [Shin-Etsu Chemical Co., Ltd.] 0.1 part Ion exchange 56.9 parts of water

<Treatment liquid N>
Cationic colloidal silica (ST-AK [Nissan Chemical Co., Ltd.]) 15.0 parts Glycerin 25.0 parts 2-Pyrrolidone 1.0 part Olefin STG 2.0 parts KM-72F (silicon-based antifoaming agent) [Shin-Etsu Chemical Co., Ltd.] 0.1 parts Lithium hydroxide 0.35 parts Ion-exchanged water 56.55 parts

<Processing liquid O>
Cationic colloidal silica (ST-AK [Nissan Chemical Co., Ltd.]) 15.0 parts Glycerin 25.0 parts 2-Pyrrolidone 1.0 part Olefin STG 2.0 parts KM-72F (silicon-based antifoaming agent) [Shin-Etsu Chemical Co., Ltd.] 0.1 parts Lithium hydroxide 0.37 parts Ion-exchanged water 56.53 parts

<Processing liquid P>
Cationic colloidal silica (ST-AK [Nissan Chemical Co., Ltd.]) 15.0 parts Glycerin 25.0 parts 2-Pyrrolidone 1.0 part Olefin STG 2.0 parts KM-72F (silicon-based antifoaming agent) [Shin-Etsu Chemical Co., Ltd.] 0.1 part 1N HCl 3.65 parts ion-exchanged water 53.25 parts

<Recording liquid I>
C. I. Pigment Red 8.0 parts 1,3-butanediol 22.5 parts Glycerol 7.5 parts Surfactant 1.0 part 2-Pyrrolidone 2.0 parts Sodium dehydroacetate 0.2 part Sodium thiosulfate 0.2 part Water 58.6 parts
(Surface tension γ2 = 33.0)

<Recording liquid II>
C. I. Pigment Red 8.0 parts Anionic colloidal silica (ST-20 [Nissan Chemical Co., Ltd.]) 5.0 parts 1,3-butanediol 22.5 parts Glycerin 7.5 parts Surfactant 1.0 part 2- Pyrrolidone 2.0 parts Sodium dehydroacetate 0.2 parts Sodium thiosulfate 0.2 parts Ion-exchanged water 53.6 parts

<Recording liquid III>
C. I. Direct Red 225 4.0 parts Ethylene glycol 15.0 parts Glycerin 5.0 parts Surfactant 1.0 part 2-Pyrrolidone 2.0 parts Sodium dehydroacetate 0.2 part Sodium thiosulfate 0.2 part Ion exchange water 72.6 parts

<Recording liquid IV>
C. I. Pigment Red 8.0 parts Ethylene glycol 15.0 parts Glycerin 5.0 parts Surfactant 1.0 part 2-Pyrrolidone 2.0 parts Sodium dehydroacetate 0.2 part Sodium thiosulfate 0.2 part Acetic acid 0.2 part Ion-exchanged water 68.4 parts

<Recording liquid V>
C. I. Pigment Red 8.0 parts Ethylene glycol 15.0 parts Glycerin 5.0 parts Surfactant 1.0 part 2-Pyrrolidone 2.0 parts Sodium dehydroacetate 0.2 part Sodium thiosulfate 0.2 part 0.1 N Hydroxide Sodium 2.0 parts Ion-exchanged water 66.6 parts

For the processing liquids A to P and the recording liquids I to V obtained as described above, the surface tension was measured by the Wilhelmi (plate) method using a surface tension measuring device CBVP-Z (manufactured by Kyowa Interface Science Co., Ltd.) The zeta potential was measured with a dense zeta potential measuring device (ultrasonic method) ESA8000 (manufactured by Matec Applied Sciences). The results are shown in Table 1-1 and Table 1-2.
The cationic components of the treatment liquids K, L, and M are a polymer electrolyte polymer, a polymer electrolyte monomer, and a polyvalent metal salt, respectively, and since they are not fine particles, the ζ potential is not measured.

Ink set <Evaluation>
Printing was performed on a recording medium using an ink set in which the treatment liquids A to P and the recording liquids I to V were combined. First, the treatment liquid was first put on the recording medium, and then the recording liquid was adhered to the recording medium. At this time, adjustment was made so that the droplet of the treatment liquid and the droplet of the recording liquid overlapped accurately. For the printing, a modified machine of Ricoh Corporation Ipsio Jet300 was used.

Evaluation Method of Recorded Image and Evaluation Criteria (1) Ejection Stability A printing sample was prepared by printing a treatment liquid or a solid patch pattern of M ink on My Paper 6200 of Ricoh Co., Ltd. using a printer. When this was carried out 50 times, the ejection stability was evaluated from the frequency at which there was no non-ejection nozzle and a complete patch pattern could be printed.
The evaluation criteria are as follows: ×: Ejection failure frequently occurs, and the probability that a printed matter with a complete patch pattern can be created is less than 1/50 Δ: Elimination failure occurs rarely, and the establishment that a printed matter with a complete patch pattern can be created Is more than 1/50 and less than 49/50. 49/50 or more A: Establishing that a complete patch pattern print can be created. No defective discharge occurs, and a complete patch pattern print can always be created.

(2) Storage stability The treatment liquid or M ink was sealed and left in an environment of 50 ° C. for 3 weeks. The storage stability was evaluated by evaluating the change in viscosity before and after such standing.
The evaluation criteria are as follows: X: treatment liquid or M ink has a very high density increase. O: A slight increase in viscosity is observed, but sufficient storage stability is maintained.
A: No increase in viscosity is observed and storage stability is ensured

(3) Image Density A print sample was prepared by printing a solid patch pattern of M ink on My Paper 6200 of Ricoh Co., Ltd. using a printer. The image density of the patch was measured by X-Rite.

(4) Back-through density A solid sample patch pattern of M ink was printed on MyPaper 6200 of Ricoh Co., Ltd. using a printer to prepare a print sample. The image density of the back surface of the patch pattern was measured with X-Rite for the patch.

(5) Color bleed Using a printer, a pattern containing the letter A of M ink in a solid of Bk ink was printed on My Paper 6200 of Ricoh Co., Ltd. to prepare a print sample. The pattern was visually evaluated for boundary bleeding. The above Bk ink is different from the recording liquid A in C.I. I. It is a recording liquid in which 10.0 parts of Cabojet 300 is added instead of Pigment Red (8.0 parts). Further, the ejection amount was almost the same as that of M ink.
The evaluation criteria are as follows: X: The characters are blurred so that the color boundary line is not clear.
Δ: Color boundary bleeding is noticeable by bleeding at many places. ○: Color boundary bleeding is partially noticeable but not noticeable.
(Double-circle): The blur of a color boundary line cannot be visually recognized.

(6) Feathering A pattern in which characters were entered with M ink using a printer was printed on My Paper 6200 of Ricoh Co., Ltd. to produce a print sample. The bleeding of the letters was evaluated visually.
The evaluation criteria are as follows: X: The characters are so blurred that the outline of the characters is not clear.
Δ: The outline of the character is blurred and noticeable in many places. ○: The blur of the outline of the character is partially blurred but is not noticeable.
(Double-circle): The blur of the outline of a character cannot be visually recognized.

(7) Saturation Using a printer, a solid ink patch pattern of M ink was printed on My Paper 6200 of Ricoh Co., Ltd. to prepare a print sample. The image density of the patch was measured by X-Rite.

(8) Liquid contact durability A 10 mm × 10 mm × 0.5 mm Ni metal plate was immersed in the treatment liquid or M ink at 50 ° C. for 10 days, and the degree of corrosion of the Ni metal plate was examined.
The evaluation criteria are as follows: X: The Ni metal plate is not corroded.
(Triangle | delta): A Ni metal plate has a hole by corrosion and cannot maintain sufficient durability.
○: Some corrosion is observed, but sufficient durability is maintained.
(Double-circle): Corrosion is not seen and it has sufficient durability.

[Multilayer structure]
<Example 1>
A printed matter was prepared using an ink set in which the treatment liquid B and the recording liquid III were combined, and the image quality was evaluated. The treatment liquid discharge amount M1 was 4.67 [g / cm ² ], and the recording liquid discharge amount M2 was 4.0162 [g / cm ² ].

<Comparative Example 1>
A printed matter was prepared using an ink set in which the treatment liquid M and the recording liquid III were combined, and the image quality was evaluated. The treatment liquid discharge amount M1 was 4.58 [g / cm ² ], and the recording liquid discharge amount M2 was 4.0162 [g / cm ² ].

実施例１の処理液Ｂと記録液IIIを組み合わせたインクセットでは多層構造を形成するが、比較例１の処理液Ｎと記録液IIIを組み合わせたインクセットでは多層構造を形成しない。
実施例１と比較例１の比較から多層構造を形成する場合の方が多層構造にならない場合に比べて画質が良くなることがわかった。

The ink set combining the treatment liquid B and the recording liquid III of Example 1 forms a multilayer structure, but the ink set combining the treatment liquid N and the recording liquid III of Comparative Example 1 does not form a multilayer structure.
From the comparison between Example 1 and Comparative Example 1, it was found that the image quality was better when the multilayer structure was formed than when the multilayer structure was not formed.

[Surface tension γ]
<Example 2>
A printed matter was prepared using an ink set in which the treatment liquid A and the recording liquid I were combined, and the image quality and ejection stability were evaluated. The treatment liquid discharge amount M1 was 4.67 [g / cm ² ], and the recording liquid discharge amount M2 was 4.0162 [g / cm ² ].

<Example 3>
A printed matter was prepared using an ink set in which the treatment liquid B and the recording liquid I were combined, and the image quality and ejection stability were evaluated. The discharge amount M1 of the treatment liquid was 4.63 [g / cm ² ], and the discharge amount M2 of the recording liquid was 4.0162 [g / cm ² ].

<Example 4>
A printed matter was prepared using an ink set in which the treatment liquid C and the recording liquid I were combined, and the image quality and ejection stability were evaluated. The treatment liquid discharge amount M1 was 4.66 [g / cm ² ], and the recording liquid discharge amount M2 was 4.0162 [g / cm ² ].

<Example 5>
A printed matter was prepared using an ink set in which the treatment liquid D and the recording liquid I were combined, and the image quality and ejection stability were evaluated. The treatment liquid discharge amount M1 was 4.64 [g / cm ² ], and the recording liquid discharge amount M2 was 4.0162 [g / cm ² ].

<Example 6>
A printed matter was prepared using an ink set in which the treatment liquid E and the recording liquid I were combined, and the image quality and ejection stability were evaluated. The treatment liquid discharge amount M1 was 4.58 [g / cm ² ], and the recording liquid discharge amount M2 was 4.0162 [g / cm ² ].

<Example 7>
A printed matter was prepared using an ink set in which the treatment liquid F and the recording liquid I were combined, and the image quality and ejection stability were evaluated. The treatment liquid discharge amount M1 was 4.64 [g / cm ² ], and the recording liquid discharge amount M2 was 4.0162 [g / cm ² ].

実施例２〜７の比較により、このような２液を記録媒体上で反応させる画像形成方法を行なう画像形成方法において処理液の表面張力γ１の範囲が１０≦γ１≦６０であるような表面張力の処理液とすることで、より高画質な印刷物が得られることを発見した。更に、より好適な範囲は１０≦γ１≦４０であり、充分に好適な範囲は１０≦γ１≦３５であることがわかった。更に、より好適な範囲は１０≦γ１≦３０であり、さらに好適な範囲は１０≦γ１≦２５であることがわかった。
γ１＞６０では充分な画質が得られず、また、γ１＜１５［ｍＮ／ｍ］では処理液ヘッドの吐出安定性が得にくくなり、γ１＜１０では吐出安定性はまったく得られなかった。
また、特に記録液の表面張力γ２に対し０．３＜γ１／γ２＜１となる範囲においてより高画質な印刷物を得られることが分かった。

In comparison with Examples 2 to 7, in the image forming method in which the image forming method in which the two liquids are reacted on the recording medium is used, the surface tension γ1 of the processing liquid is in the range of 10 ≦ γ1 ≦ 60. It was discovered that a higher-quality printed material can be obtained by using the above-mentioned treatment liquid. Furthermore, it was found that a more preferable range is 10 ≦ γ1 ≦ 40, and a sufficiently preferable range is 10 ≦ γ1 ≦ 35. Furthermore, it was found that a more preferable range is 10 ≦ γ1 ≦ 30, and a more preferable range is 10 ≦ γ1 ≦ 25.
When γ1> 60, sufficient image quality cannot be obtained, and when γ1 <15 [mN / m], it is difficult to obtain the discharge stability of the treatment liquid head, and when γ1 <10, no discharge stability is obtained.
It was also found that a higher quality print can be obtained particularly in the range of 0.3 <γ1 / γ2 <1 with respect to the surface tension γ2 of the recording liquid.

[Defoaming agent concentration]
<Example 8>
A printed matter was prepared using an ink set in which the treatment liquid G and the recording liquid II were combined, and the ejection stability was evaluated.

<Example 9>
A printed matter was prepared using an ink set in which the treatment liquid H and the recording liquid II were combined, and the ejection stability was evaluated.

<Comparative example 2>
A printed matter was prepared using an ink set in which the treatment liquid I and the recording liquid II were combined, and the discharge stability was evaluated.

<Comparative Example 3>
A printed matter was prepared using an ink set in which the treatment liquid J and the recording liquid I were combined, and the ejection stability was evaluated.

When Examples 2, 7, 8 and Comparative Examples 2 and 3 were compared, in the heads for discharging the processing liquid, the processing liquid could be discharged in Examples 2, 1 and 2, but the processing liquid I was used. In Comparative Example 2, bubbles generated in the treatment liquid were involved, and stable ejection could not be secured. Further, in Comparative Example 3 using the treatment liquid J, clogging occurred in the nozzle of the head that ejects the treatment liquid, and stable ejection could not be secured.
The surface tension γ1 of the treatment liquid used at this time is a treatment liquid with a relatively low surface tension of γ1 ≦ 35.
From this, the antifoaming agent to be contained in the treatment liquid can be contained within a range of 0.001 wt% to 10 wt%, thereby ensuring discharge stability even when the surface tension is low, and creating a printed matter. I knew it would be possible.

[Processing liquid aggregation component]
<Example 10>
A printed matter was prepared using an ink set in which the treatment liquid K and the recording liquid I were combined, and the image quality and ejection stability were evaluated. The discharge amount M1 of the treatment liquid was 4.63 [g / cm ² ], and the discharge amount M2 of the recording liquid was 4.0162 [g / cm ² ].

<Example 11>
A printed matter was prepared using an ink set in which the treatment liquid L and the recording liquid I were combined, and the image quality and ejection stability were evaluated. The treatment liquid discharge amount M1 was 4.64 [g / cm ² ], and the recording liquid discharge amount M2 was 4.0162 [g / cm ² ].

<Example 12>
A printed matter was prepared using an ink set in which the treatment liquid M and the recording liquid I were combined, and the image quality and ejection stability were evaluated. The treatment liquid discharge amount M1 was 4.67 [g / cm ² ], and the recording liquid discharge amount M2 was 4.0162 [g / cm ² ].

<Comparative example 4>
A printed matter was prepared using an ink using only the recording liquid I without using the treatment liquid, and the image quality and ejection stability were evaluated. The treatment liquid discharge amount M1 was 4.67 [g / cm ² ], and the recording liquid discharge amount M2 was 4.0162 [g / cm ² ].

From Examples 3, 10 to 12, and Comparative Example 4, it was found that the aggregation component of the treatment liquid may be a fine particle, a polymer, a monomer, or a polyvalent metal salt. . It turned out that fine particles are particularly desirable.
Further, it is desirable that the aggregation component of the processing liquid has a reverse polarity with respect to the aggregation component of the recording liquid.

[Treatment solution ζ potential]
<Example 13>
A printed matter was prepared using an ink set in which the treatment liquid N and the recording liquid I were combined, and the image quality and ejection stability were evaluated. The treatment liquid discharge amount M1 was 4.57 [g / cm ² ], and the recording liquid discharge amount M2 was 4.0162 [g / cm ² ].

<Comparative Example 5>
A printed matter was prepared using an ink set in which the treatment liquid O and the recording liquid I were combined, and the image quality was evaluated. The treatment liquid discharge amount M1 was 4.69 [g / cm ² ], and the recording liquid discharge amount M2 was 4.0162 [g / cm ² ].

From comparison between Examples 3 and 13 and Comparative Example 5, it was found that a treatment solution having a ζ potential ζ1 of +5 to +90 mV was suitable. When ζ1> +90 mV with respect to the ζ potential ζ1 of the treatment liquid, it was difficult to obtain a high-quality printed matter. It is presumed that after the aggregation component and a part of the recording liquid are aggregated, most of the aggregation component does not lose the surface charge and the dispersion stability is maintained.
On the other hand, when a processing solution with ζ1 <+5 mV is used, the image quality is worse than that with ζ1 in the range of +5 to +90 mV. It is presumed that the aggregated component in the treatment liquid is weak in the ability to adsorb the aggregated component in the recording liquid, so that it is difficult to aggregate and a high-quality printed matter cannot be obtained.

[Treatment solution pH]
<Example 14>
The storage stability of the processing solutions B, N, and O was evaluated by the change in viscosity when the processing solution was stored at 50 ° C. for 3 weeks.

処理液Ｂ，Ｎに５０度、３週間の保存試験のあと、粘度増加が見られた。これは処理液に含有される微粒子の等電点となるｐＨのごく近傍でにあるためと考えられた。特に処理液Ｏのようなζ電位がζ１＜＋５ｍＶであるカチオン性微粒子を含有する処理液は保存安定性が悪く、処理液はゲル状になった。

An increase in viscosity was observed in the treatment liquids B and N after a storage test of 50 degrees and 3 weeks. This is considered to be because the pH is very close to the isoelectric point of the fine particles contained in the treatment liquid. In particular, the treatment liquid containing cationic fine particles having a ζ potential of ζ1 <+5 mV like the treatment liquid O has poor storage stability, and the treatment liquid became a gel.

[Treatment solution pH]
<Example 15>
A 10 mm × 10 mm × 0.5 mm Ni metal plate was immersed in the treatment liquids P, B, and O at 50 ° C. for 10 days, and the degree of corrosion of the Ni metal plate was examined.

処理液ＰはＮｉ金属板が腐食により充分な耐久性を保てなくなった。

The treatment liquid P could not maintain sufficient durability due to corrosion of the Ni metal plate.

<Example 16>
The storage stability of the treatment liquids P, B, and O was evaluated by the change in viscosity when the treatment liquid was stored at 50 ° C. for 3 weeks.

ｐＨが７より大きい塩基性の処理液Ｏは粘度増加を起こし、保存安定性が低いことが分かった。

It was found that the basic treatment liquid O having a pH higher than 7 caused an increase in viscosity and low storage stability.

[Recording liquid aggregation component]
<Example 17>
A printed matter was prepared using an ink set in which the treatment liquid B and the recording liquid II were combined, and the image quality was evaluated. The treatment liquid discharge amount M1 was 4.67 [g / cm ² ], and the recording liquid discharge amount M2 was 4.0162 [g / cm ² ].

<Example 18>
A printed matter was prepared using an ink set in which the treatment liquid B and the recording liquid III were combined, and the image quality was evaluated. The treatment liquid discharge amount M1 was 4.59 [g / cm ² ], and the recording liquid discharge amount M2 was 4.0162 [g / cm ² ].

実施例３、１７，１８から記録液に含有される処理液に含有される成分と凝集する成分としては、顔料でも良く、染料でも良く、該処理液に含有される成分と逆極性の成分が含有されてもよいことが分かった。
画像濃度、裏抜け濃度、フェザリング、カラーブリードで比較すると記録液に含有される処理液に含有される成分と凝集する成分としてはアニオン性顔料がアニオン性染料より高画質の印刷物を得られ、個々に処理液なしの印刷物の画質と比べても画質の向上幅が大きい。また、アニオン性の微粒子等を添加することで画質向上効果を増加することができる。
彩度で比較すると染料を添加した記録液の方が高彩度の印刷物を得られるが、処理液なしの印刷物と個々に比べると顔料の方が彩度の向上率は高い。また同様に、アニオン性の微粒子等を添加することで画質向上効果を増加することができる。

As components that aggregate with the components contained in the processing liquid contained in the recording liquid from Examples 3, 17, and 18, pigments or dyes may be used, and components having a polarity opposite to that contained in the processing liquid may be used. It was found that it may be contained.
Compared with image density, back-through density, feathering, color bleed, components that agglomerate with components contained in the processing liquid contained in the recording liquid, an anionic pigment can be obtained a higher quality print than an anionic dye, The improvement in image quality is large compared to the image quality of printed matter without treatment liquid individually. Moreover, the image quality improvement effect can be increased by adding anionic fine particles and the like.
When compared in terms of saturation, the recording liquid to which the dye is added can obtain a printed matter with higher saturation, but the pigment has a higher saturation improvement rate than the printed matter without the treatment liquid. Similarly, the effect of improving the image quality can be increased by adding anionic fine particles and the like.

[Recording solution pH]
<Example 19>
The storage stability of the recording liquids I, IV and V was evaluated by the change in viscosity when the processing liquid was stored at 50 ° C. for 3 weeks.

ｐＨが７より小さい記録液IVは反応前から粘度増加を起こし、保存安定性が低いことが分かった。

It was found that the recording liquid IV having a pH of less than 7 caused an increase in viscosity before the reaction, and the storage stability was low.

<Example 20>
A 10 mm × 10 mm × 0.5 mm Ni metal plate was immersed in recording liquids I, IV, and V at 50 ° C. for 10 days, and the degree of corrosion of the Ni metal plate was examined.

記録液Ｖでは金属板が腐食により耐久性が保てなかった。

In recording liquid V, the durability of the metal plate could not be maintained due to corrosion.

Ink set [pH]
<Comparative Example 6>
Prints were prepared using an ink set in which the treatment liquid B and the recording liquid I, and the treatment liquid N and the recording liquid I were combined, and the image quality was evaluated. The treatment liquid discharge amount M1 was 4.57 [g / cm ² ], and the recording liquid discharge amount M2 was 4.0162 [g / cm ² ]. The pH of the treatment liquid, a was a = 8.1, and the pH b of the recording liquid was b = 8.3.

実施例３と比較例６の比較により、２液のｐＨの差ｂ−ａはｂ−ａ≦２において充分な画質を得られることが分かった。濃度の高い酸や塩基がより２液が接したときの反応を強くするためと考えられる。

Comparison between Example 3 and Comparative Example 6 shows that sufficient image quality can be obtained when the difference b−a between the two liquids is b−a ≦ 2. This is considered to strengthen the reaction when two liquids are in contact with a higher concentration of acid or base.

[Discharge rate]
<Example 20>
A printed matter was prepared using an ink set in which the treatment liquid B and the recording liquid I were combined, and the image quality was evaluated. The treatment liquid discharge amount M1 was 5.4 [g / cm ² ], and the recording liquid discharge amount M2 was 6.9 [g / cm ² ].

<Example 21>
A printed matter was prepared using an ink set in which the treatment liquid A and the recording liquid I were combined, and the image quality was evaluated. The treatment liquid discharge amount M1 was 10.3 [g / cm ² ], and the recording liquid discharge amount M2 was 20.9 [g / cm ² ].

<Comparative Example 21>
A printed matter was prepared using an ink set in which the treatment liquid B and the recording liquid I were combined, and the image quality was evaluated. The treatment liquid discharge amount M1 was 3.9 [g / cm ² ], and the recording liquid discharge amount M2 was 20.9 [g / cm ² ].

<Comparative Example 22>
A printed matter was prepared using an ink set in which the treatment liquid B and the recording liquid I were combined, and the image quality was evaluated. The treatment liquid discharge amount M1 was 10.3 [g / cm ² ], and the recording liquid discharge amount M2 was 4.29 [g / cm ² ].

実施例３，２１，２２と比較例２１，２２の比較により、処理液の吐出量Ｍ１と記録液の吐出量Ｍ２の吐出量の割合は、０．２≦Ｍ１／Ｍ２≦３．０の範囲においてより高画質な印刷物を得ることができる。Ｍ１／Ｍ２＜０．２では記録液の吐出量に対して処理液の吐出量が充分ではないため記録液の凝集反応が充分に起こらない。このため画像濃度が充分でなく、裏抜け濃度が高くなり、フェザリング、カラーブリードが生じて画像が乱れる。逆にＭ１／Ｍ２＞３．０では記録液の吐出量にたいして処理液の吐出量が多すぎるため、処理液の凝集反応が充分でなく、記録液の浸透を充分に妨げられないため、やはり、充分な画像濃度が得られず、裏抜け濃度画が増加し、フェザリング、カラーブリードが生じて画像が乱れる。

According to the comparison between Examples 3, 21, 22 and Comparative Examples 21, 22, the ratio of the discharge amount M1 of the processing liquid and the discharge amount M2 of the recording liquid is in the range of 0.2 ≦ M1 / M2 ≦ 3.0. As a result, it is possible to obtain a printed matter with higher image quality. When M1 / M2 <0.2, the treatment liquid ejection amount is not sufficient relative to the recording liquid ejection amount, so that the aggregation reaction of the recording liquid does not occur sufficiently. For this reason, the image density is not sufficient, the back-through density increases, feathering and color bleeding occur, and the image is disturbed. On the other hand, when M1 / M2> 3.0, since the discharge amount of the processing liquid is too much for the discharge amount of the recording liquid, the aggregation reaction of the processing liquid is not sufficient and the penetration of the recording liquid is not sufficiently prevented. A sufficient image density cannot be obtained, the back-through density image increases, feathering and color bleeding occur, and the image is distorted.

1 is an example of an image forming apparatus according to the present invention. 2 is an example of a recording head in the present invention. It is another example of the recording head in this invention. FIG. 2 is an external perspective view of the cartridge before being loaded into the image recording apparatus according to the present invention. It is a front sectional view of the cartridge in the present invention. It is explanatory drawing of the mechanism in which the image formation method in this invention can obtain the printed matter of especially high image quality from the conventional one. It is explanatory drawing of the mechanism in which the high quality printed matter is obtained in the image forming method in this invention. FIG. 5 is a schematic diagram illustrating a process in which fine particles in a processing liquid and a coloring material in a recording liquid are substantially not mixed and formed into an image by an image forming method using the ink set of the present invention. 2 is a cross-sectional photograph of a recorded matter by one-pass printing in which an inkjet recording head is scanned once to form an image. 2 is a cross-sectional photograph of a recorded matter by multi-pass printing in which an inkjet recording head is scanned a plurality of times to form an image.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Recording head 2 Main body housing | casing 7 Processing liquid and recording liquid common cartridge 16 Gear mechanism 17 Sub scanning motor 18 Carriage 20 Recording liquid cartridge 21 Guide shaft 22 Guide shaft 23 Timing belt 24 Main scanning motor 25 Main scanning motor 26 Main scanning motor 27 Main scanning motor 31 Nozzle for discharging processing liquid Nozzle for discharging recording liquid 33 Nozzle for discharging recording liquid Nozzle for discharging recording liquid 35 Nozzle for discharging recording liquid 36 Processing liquid is discharged Nozzle 37 Nozzle for discharging recording liquid 38 Nozzle for discharging recording liquid 39 Nozzle for discharging recording liquid 40 Nozzle for discharging recording liquid 41 Nozzle for discharging processing liquid 41 Cartridge housing 42 Liquid absorber 43 Case 44 Upper lid member 45 Liquid supply port 46 Seal ring 47 Large Release port 48 groove 50 recess A space cap member 51 leakage preventing projection 53 the cap member 55 sealing member 71 cartridge positioning portion 81 cartridge detachable protruded portion 81a cartridge for attaching and detaching the finger hook portion 82 cartridge detachable

Claims (22)

An ink set comprising a recording liquid containing an anionic component and a processing liquid containing a component reactive with the components in the recording liquid, the processing liquid and the recording liquid being used as a recording medium by overlapping, are those that form a layer which is formed by the components constituting substantially the recording liquid, the recording unit which is divided into a layer formed by components constituting a substantially the process solution, the The recording liquid contains a coloring material, a surfactant, water and a water-soluble organic solvent, and the treatment liquid contains cationic inorganic fine particles, water, a water-soluble organic solvent and a silicon-based antifoaming agent, and the surface tension γ is 10 ≦ γ ≦ 35 [mN / m] , the content of the antifoaming agent is 0.001 wt% to 10 wt%, and the surface tension of the treatment liquid is smaller than the surface tension of the recording liquid. Ink set. The ink set according to claim 1, wherein the antifoaming agent is an emulsion type. 3. The ink set according to claim 1, wherein the surface tension γ of the treatment liquid is 10 ≦ γ ≦ 30 [mN / m]. 3. The ink set according to claim 1, wherein the surface tension γ of the treatment liquid is 10 ≦ γ ≦ 25 [mN / m]. The ink set according to any one of claims 1 to 4 , wherein a difference in surface tension between the recording liquid and the treatment liquid is 2 [mN / m] or more. The pH of the treatment liquid a, when the pH of the recording liquid expressed by a and b, respectively, the ink set according to any of claims 1 to 5, characterized in that a b-a ≧ 2. When the discharge amount of the processing liquid and the recording liquid were respectively M1, M2, ink set according to any one of claims 1 to 6, characterized in that a 0.2 ≦ M1 / M2 ≦ 3.0. The ink set according to any one of claims 1 to 7 , wherein the treatment liquid includes a ζ potential of the cationic inorganic fine particles in a range of +5 to +90 [mV]. The treatment liquid, ink set according to any one of claims 1 to 8, characterized in that it contains a cationic surfactant or nonionic surfactant. The treatment liquid, ink set according to any one of claims 1 to 9, characterized in that it is adjusted to contain an acid pH 2-7. The ink set according to claim 10 , wherein the acid has a temporary dissociation constant pKa in water of 5 or less. The ink set according to claim 1 to 11, wherein the anionic component of the recording liquid is particulate. The ink set according to claim 12 , wherein the recording liquid has an ζ potential of anionic fine particles in a range of −90 to −5 [mV]. The ink set according to any of claims 1 to 13, wherein the colorant of the recording liquid is a pigment. The ink set according to any of claims 1 to 14, wherein the colorant is a dye. The ink set according to any of claims 1 to 15 recording liquid characterized by containing an anionic surfactant or nonionic surfactant. The ink set according to any one of claims 1 to 16 , wherein the recording liquid contains a base and the pH is adjusted to 7 to 12. The ink set according to claim 17 , wherein the base has a temporary dissociation constant pKb in water of 5 or less. Image forming method which comprises using the ink set according to any one of claims 1 to 18. A storage unit that independently stores a recording liquid containing a color material and a processing liquid containing a component that is reactive with the components in the recording liquid, and a discharge that individually discharges the recording liquid and the processing liquid. An image forming apparatus provided with a means for sequentially ejecting the recording liquid and the treatment liquid onto a recording medium to form a recording portion, and a section of the recording portion substantially constitutes the recording liquid. A layer formed of components and a layer formed of components substantially constituting the processing liquid are formed separately, and the recording liquid and the processing liquid are described in any one of claims 1 to 18. An image forming apparatus characterized by being an ink set. 21. A printed matter printed by the image forming apparatus according to claim 20 . Processing liquid cartridge, characterized in that to accommodate the ink set according to any one of claims 1 to 18.

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