JP2002088288A - Ink set, ink jet printing method by using the ink set, recording unit, ink cartridge, and ink jet printing device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for forming a high-quality image excellent in fixability by ink jet recording using a pigment ink. SOLUTION: An ink set is prepared which contains a first ink containing an anionic dye and an aqueous medium; a second ink containing an anionic dye and an aqueous medium, having a coloring material concentration lower than that of the first ink, and also containing a substance capable of destabilizing the dispersion of at least one of the first pigment and the second pigment in the third ink described below when in contact in a liquid state with the third ink on a printing medium; and a third ink containing a dispersion of a first self-dispersible pigment and a second pigment, a polymeric dispersant for dispersing the second pigment, and an aqueous medium. Those inks are applied by an ink jet recording method on a printing medium in such a manner that at least the second ink and the third ink will contact with each other to react the constituents of the second ink with those of the third ink, thus forming a print.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to an ink set, an ink jet printing method, a recording unit, an ink cartridge, and an ink jet printing apparatus.

[0002]

2. Description of the Related Art With the spread of ink jet printers and the like, one trend in these apparatuses is to perform higher quality printing. It is well known that one of the main factors that determine the print quality is an optical density (hereinafter, also simply referred to as “OD”) realized as an ink dot or a group of the ink dots on a print medium. is there. For example, when printing a character such as a black character, generally, the higher the OD of the dot formed on the print medium by the black ink, the higher the printed character has a higher contrast with the background color of the print medium and the print quality. Improves. Also, in the case of dots of other colors, for example, dots of cyan, magenta, and yellow, the higher the OD, the clearer the image.

One of the factors that affect the OD of dots formed on a print medium by ink is the amount of ink color material that does not penetrate into the print medium and remains on the surface. From this point, it is known to increase the ejection amount itself of the print head. However, as a simpler method, for example, the print head is scanned a plurality of times, and thereby, the ink is ejected to the same place a plurality of times. It is widely used to increase the amount of ink applied to a print medium.

[0004] As another method of leaving a large amount of color material on the print medium surface, a treatment liquid for insolubilizing the color material is applied to the print medium together with the ink. Ways to improve are also being provided.

From this viewpoint, the present applicant has disclosed in
A printing apparatus and a printing method described in JP 1930 are proposed. Here, in a region where black is to be printed, black ink is discharged to this region, and the processing liquid is discharged in a predetermined pixel pattern. In addition, the treatment liquid also serves as a cyan ink having a polarity different from the anion of the black ink and a cationic property, whereby the above-described effect of increasing the concentration of insolubilizing the coloring material of the black ink can be obtained. . Further, by simultaneously patterning and printing other colors, the density is increased while preventing a color tone shift.

[0006] The invention described in the above-mentioned publications not only improves the print quality due to the above-described increase in density, but also does not require a print head dedicated to the processing liquid, improves the water resistance of the processing liquid with a simple structure, and reduces the feather density. An effect such as prevention of ring and bleed can be obtained.

[0007] As a similar technique, a technique disclosed in a gazette of European Patent Application No. EP A831135 is also known. Here, it is disclosed that, for a magenta or cyan color ink, a lighter color ink having a lower density is printed on top of a black ink, and the black ink is insolubilized using components in these light color inks.

[0008] On the other hand, generally, an ink to be used is selected from the viewpoints of print characteristics such as ejection characteristics and fixability, and bleeding of a printed image, optical reflection density, and print quality such as coloration. By the way, it is widely known that inks are roughly classified into two types, dye inks and pigment inks, depending on the coloring materials contained therein.

[0009] Among these, pigment inks have advantages such as superior water resistance and light resistance as compared with dye inks, and enable clear character quality. On the other hand, the pigment ink may take longer to fix to the print medium than the dye ink, or may not have sufficient abrasion resistance of the image after fixing, and may be ejected from the nozzle by one ejection operation. There is a tendency that the size of the ink dots formed on the print medium by the ink becomes smaller. That is, the pigment contained in the pigment ink is usually mainly utilizing the electric repulsive force of the polymer dispersant to overcome the intermolecular force acting between the pigment particles that causes the aggregation of the pigment particles. It is one that is stably dispersed in the ink. Therefore, it is preferable to add a polymer dispersant to the ink according to the amount of the pigment. Further, an ink using a self-dispersion type pigment has been proposed.

On the other hand, in the ink jet printing technique, the ink and the ink react with the ink for the purpose of further improving print quality and image quality (for example, improvement of water resistance and optical density (OD) of an image on a print medium). A method of applying a treatment liquid onto a print medium so that the ink and the treatment liquid react on the print medium has been proposed and put to practical use.

[0011]

DISCLOSURE OF THE INVENTION The present inventors have conducted studies to solve the problems peculiar to the pigment ink while utilizing the excellent characteristics of the pigment ink, and have obtained the following findings.

When a pigment ink, in which a pigment is dispersed by a polymer dispersant, is printed on plain paper by an ink jet recording method, the penetration of the solvent of the ink such as moisture into the paper,
And the pigments aggregate due to evaporation into the air. At this time, the behavior of the ink on the paper is such that the larger the amount of the polymer dispersant contained in the ink, the stronger the cohesive force of the ink. Therefore, the ink dot diameter obtained by the ink having a high content of the polymer dispersant is smaller than the ink dot diameter obtained by the ink having a low content,
Further, the dot shape remains close to the distorted shape when colliding with the paper. Therefore, in order to obtain an ink dot having a recording density sufficient for forming an image and having a dot diameter required for recording such that white streaks do not occur, the ejection volume of ink from the inkjet head must be increased. Need to be done. However, even with such an adjustment, coupled with a decrease in the permeability into the paper due to the strong cohesive force of the pigment particles to which the polymer dispersant is adsorbed, the fixing of the ink to the print medium is delayed, Alternatively, the scratch resistance of the recorded image may be reduced.

[0013] Further, in order to increase the dot diameter and to improve the fixability, it has been considered that a penetrant is included in the ink for the purpose of improving the permeability of the ink into the print medium.
However, this is accompanied by undesirable phenomena such as deterioration of the dot shape (deterioration of the dot peripheral shape such as so-called feathering) and permeation of the ink on the back surface of the paper (so-called strike-through). There are cases. Also,
Since the color material permeates into the print medium, the OD of the ink dot often does not increase so much even if the dot diameter becomes relatively large.

On the other hand, in the ink using the self-dispersion type pigment, the dot diameter may be increased because the cohesive force of the pigment on the paper is weaker than the ink containing the pigment dispersed by the above-described dispersant. But still not enough to get a high quality image.

Therefore, the present inventors have developed various factors which influence the quality of a recorded image, for example, the fixing property of ink,
As a printing method that satisfies a high level of ink dot diameter enlargement, density uniformity within the ink dot, high optical density of the ink dot itself, etc., the case of the pigment ink alone, the pigment ink, and the pigment ink Vigorous studies have been made on research on ink jet recording technology when used in combination with a treatment liquid having a reactivity with the pigment ink that destroys pigment dispersibility during recording. As a part of the study, a recording process was performed in which a pigment ink was applied so as to be mixed with the treatment liquid on the print medium in a liquid state before and after the treatment liquid was applied to the print medium surface.

However, the resulting image was sometimes unsatisfactory in terms of its quality, and was even observed to be of lower quality than the image formed with the pigment ink alone. Specifically, for example, in a combination of a pigment ink containing a pigment dispersed in an aqueous medium with a polymer dispersant as the pigment ink and a treatment liquid that reacts with the pigment ink, the area factor of the ink dots is small. In some cases, a decrease in optical density (OD) was observed. Although the reason why such a phenomenon occurs is not clear, it is considered that the aggregation of the pigment in the ink on the print medium was greatly promoted by the treatment liquid.

For this reason, the area factor can be increased and the OD can be improved by increasing the amount of the pigment ink to be discharged. However, in this case, it is sometimes recognized that the fixability is inferior. In addition, a so-called “exudation” or “saturation” is provided at the edge portion of a dot on a print medium obtained by a combination of a pigment ink containing a self-dispersible pigment as a pigment ink and a treatment liquid that reacts with the pigment ink. A phenomenon called "haze" occurred, and clear dots could not be obtained.

FIG. 1 is a schematic plan view of a dot on which the “exudation” or “haze” has occurred. A dot around the reaction portion between the central pigment ink 8 and the processing liquid 6 is indicated by “exudation”. "Haze" part 7 is observed.

FIG. 2 is a diagram for estimating the mechanism of occurrence of this phenomenon. After the treatment liquid S is applied to the print medium P (especially plain paper, etc.), the pigment ink Ip containing the self-dispersible pigment and containing no polymer dispersant is applied in a position where the treatment liquid S is applied. When done, reactant (2)
Starts (see FIG. 2B). Then, as this reaction progresses, as shown in FIG. 3 (c), a radial "exudation" occurs from the substantially circular dot of the reactant, and the entire dot appears to have a "mist" around it. It becomes a state. Such “exudation” or “mist” is apparently recognized in the same manner as well-known feathering, and thus degrades print quality.

The above-mentioned "exudation" or "haze"
Supposes the following phenomenon chemically or microscopically. The dispersant-free pigment ink has a relatively high reaction rate in the reaction with the processing liquid, and thus the dispersed pigment instantly causes dispersion destruction and forms a cluster of reactants, but with this, fine It also gives rise to particulate reactants. Then, the particulate reactant penetrates the print medium with the treatment liquid shown in FIG.
It is thought that the above-mentioned “exudation” and “haze” appear as a result as the water flows along with the expansion of the image.

As described above, simply combining the pigment ink and the processing liquid causes an event that cannot be predicted by the present inventors, and it is sometimes difficult to obtain a high-quality ink jet recorded image. . In addition, it is necessary to further develop the technology to achieve the intended purpose of improving the disadvantages of the pigment ink while utilizing the advantages of the pigment ink by utilizing the inkjet recording technology using the processing liquid. The present inventors have recognized.

Further, when considering the development of the ink jet printer in the business field, it is considered that a further improvement in the printing speed will be required. One of the major issues in such a high-speed printer is the fixability of ink to a recording medium. If the fixability is poor, in the process of laminating the subsequent recording medium on the surface of the printed recording medium discharged earlier, the print on the surface of the previous recording medium is stained, or on the back side of the subsequent recording medium. In such a case, the ink discharged from the recording medium may adhere to the recording medium, which may lower the print quality or impair the appearance of the printed matter. on the other hand,
The demand for higher image quality for color images by the ink jet method is also becoming extremely sophisticated.

The present invention has been made in view of the above-mentioned new technical knowledge, and is an ink for obtaining a higher quality color print by using an ink jet recording technique using a pigment ink and a processing liquid. To provide a set.

Another object of the present invention is to provide a color ink-jet printing method and apparatus capable of fixing ink at a high speed on a recording medium without deteriorating the quality of a printed matter.

[0025]

An ink set according to an embodiment of the present invention, which can achieve the above object, comprises a first ink, a second ink and a second ink, each containing an aqueous medium and a coloring material. 3. An ink set including the ink of No. 3, wherein the first ink includes an anionic dye as a coloring material, the second ink includes an anionic dye as a coloring material, and the first ink includes The third ink has a lower colorant concentration than the first ink, and includes a first pigment, a second pigment, and a polymer dispersant for dispersing the second pigment.
And the second pigment are both contained in the ink in a dispersed state in the ink, and the first pigment has a surface of the first pigment in which at least one anionic group is directly or through another atomic group. A self-dispersible pigment bonded to the second
Is a pigment that can be dispersed in the aqueous medium by a polymer dispersant, wherein the polymer dispersant is at least one of an anionic polymer dispersant and a nonionic polymer dispersant, and When the second ink comes into contact with the third ink in a liquid state on a print medium, the third ink forms the third ink.
And a substance that destabilizes the dispersion stability of at least one of the first pigment and the second pigment in the ink.

The color ink jet recording method according to one embodiment of the present invention, which can achieve the above object, comprises: (1) an ink jet method comprising the steps of: (1) using a first ink containing an aqueous medium and an anionic dye as a coloring material (2) a second ink containing an aqueous medium and an anionic dye as a colorant, and having a lower colorant concentration than the first ink by inkjet printing; A second step of depositing on a print medium using a method; and (3) a first pigment, a second pigment in an aqueous medium,
A polymer dispersant for dispersing the second pigment, wherein the first pigment and the second pigment are both contained in a dispersed state, and the first pigment has at least one anionic group. A pigment which is a self-dispersible pigment bonded to the surface of the first pigment directly or via another atomic group, wherein the second pigment can be dispersed in the aqueous medium by a polymer dispersant. A third step of attaching the third ink, wherein the polymer dispersant is at least one of an anionic polymer dispersant and a nonionic polymer dispersant, onto a print medium using an inkjet method, And the second
Destabilizes the dispersion stability of at least one of the first pigment and the second pigment in the third ink when in contact with the third ink in a liquid state on a print medium And the second step is in contact with the second ink and the third ink in a liquid state on the print medium following or substantially simultaneously with the third step. It is characterized by performing as follows.

According to the invention according to the above aspect,
Very high OD, good edge sharpness,
A higher quality image can be obtained, and various merits such as improvement of scratch resistance and fixing property can be obtained. A substance that destabilizes the dispersion stability of at least one of the first pigment and the second pigment subsequent to or substantially simultaneously with the application of the third ink containing the first pigment and the second pigment. It is not clear why the application of the second ink containing the above provides such an effect. However, the present inventors have confirmed the following facts through a plurality of experiments on the present invention. That is, when the third ink containing the first and second pigments is applied to a print medium, the ink forms dots having a predetermined spread on the surface of the print medium P as shown in FIG. Is done. The size (diameter: d1) of the ink dot is the same as the size (diameter: diameter of the conventional pigment ink (ink in which the pigment is dispersed by the polymer dispersant or ink including the self-dispersion type pigment) shown in FIG. It is larger than d2) (d1> d2).

The reason why such a phenomenon is observed is not clear, but is presumed to be due to the following mechanism. That is, the second pigment and the first pigment to which the polymer dispersant is adsorbed are electrically repelled in the ink, and the cohesive force of the pigment is weaker than at least the ink containing only the polymer dispersed pigment. . When such an ink is printed on the paper surface, the coloring material in the ink hardly permeates in the thickness direction of the paper because the polymer dispersant is adsorbed on the second pigment. On the other hand, in the case of the ink containing the second pigment and the polymer dispersant, the solvent of the ink permeates the paper in the paper surface (horizontal) direction,
The pigments are strongly agglomerated due to the sudden entanglement of polymers with the decrease in water content due to evaporation or the cross-linking of polymers between the pigments, whereas the ink of the present embodiment contains the first pigment. This prevents or suppresses the entanglement or cross-linking of the polymer, and the repulsion between the first pigment and the polymer dispersant reduces the strong intermolecular force between the pigments in the ink. As a result, It is considered that the ink is easily diffused in the lateral direction of the paper surface, and that the diffusion is reduced, but the ink is affected by the cohesive force between the pigments, so that the ink is not irregularly diffused.

Then, the first pigment and the second pigment are added to the ink dots thus uniformly and widely diffused on the surface of the print medium.
When a second ink containing a substance that destabilizes the dispersion stability of at least one of the pigments is applied (see FIGS. 2B and 2C), the third ink and the second ink However, as described above, since the ink dots are widely diffused, the reaction area between the second ink and the third ink is also smaller than that of the conventional ink. Since the ink dots are wide and the ink dots are widely spread, the thickness (t1) of the ink dots is thinner than the thickness (t2) of the conventional ink dots on the print medium surface, and the reaction with the second ink is very short. It is thought that it ends with. It is presumed that this leads to a reduction in the fixing time and an improvement in the fixing property, and an improvement in the edge sharpness of the ink dots. From such a mechanism, it can be understood that the effect achieved by this embodiment is peculiar to a system in which the third ink is applied to the print medium before or substantially simultaneously with the second ink.

In the present embodiment, when the second ink has excellent permeability to the print medium, the fixability and the edge sharpness of the ink dots are further improved. It is considered that this is because the third ink and the second ink react on the print medium surface, and the permeability of the solvent including water into the print medium is improved by the penetrating force of the second ink. In general, when a coloring material is penetrated into a print medium, the optical density often decreases. However, when the third ink is applied prior to the application of the second ink as in the present embodiment, the OD is reduced. Hardly penetrates the print media to such an extent as to cause a decrease in the pigment. Rather, the reaction with the second ink makes it easier for the coloring material to remain on the surface of the print medium and in the vicinity thereof, and as a result, it has been found that the OD is further improved as compared with the case where the second ink is not used. ing.

Another embodiment of the ink jet printing method capable of achieving the above object is (1)
A first step of depositing a first ink containing an aqueous medium and an anionic dye as a colorant on a print medium using an inkjet method, (2) containing an aqueous medium and an anionic dye as a colorant, and A second step of depositing a second ink having a lower colorant concentration than the first ink on a print medium by using an inkjet method; and (3) disposing the first pigment and the second pigment in an aqueous medium. 2 and a polymer dispersant for dispersing the second pigment, the first pigment and the second pigment are both contained in a dispersed state, and the first pigment is at least one A self-dispersible pigment in which an anionic group is bonded directly or via another atomic group to the surface of the first pigment, wherein the second pigment is dispersed in the aqueous medium by a polymer dispersant. The polymer dispersion Applying a third ink, which is at least one of an anionic polymer dispersant and a nonionic polymer dispersant, onto a print medium using an inkjet method, the second ink comprising: Is in contact with the third ink in a liquid state on a print medium,
A substance that destabilizes the dispersion stability of at least one of the first pigment and the second pigment in the third ink, and wherein the third step is performed after the second step. The second ink and the third ink are in contact with each other in a liquid state on the print medium.

According to the embodiment of the present invention as described above, it is possible to obtain a higher-quality image having an extremely high OD, a reduced "haze", and abrasion resistance and fixing property. Various advantages such as improvement can be obtained. The reason why such an effect can be obtained by this embodiment is not clear, but the present inventors have confirmed the following facts through various experiments on the present invention. That is, after applying a second ink further containing a substance that destabilizes the dispersion stability of at least one of the first pigment and the second pigment to a print medium, the second ink is applied to a portion to which the second ink is applied. When the third ink is applied so as to be overlapped or in contact with each other in a liquid state, the ink dot spreads relatively largely to the portion where the second ink is applied, and becomes an ink dot having a large diameter. The first and second inks in the third ink
Is present in the second ink and the third ink by coexisting with the second ink containing a substance that destabilizes the dispersion stability of at least one of the first pigment and the second pigment. It is inferred that the aggregation of at least one of the first pigment and the second pigment is alleviated.

[0033] A second ink containing a substance that destabilizes the dispersion stability of at least one of the first pigment and the second pigment, and a third ink whose dispersion stability is destabilized by the substance. Agglomeration due to a strong reaction with one pigment in the ink is mitigated by a relatively weak reaction between the other pigment in the third ink and the second ink. It is considered that the strong intermolecular force between the pigments is reduced by the presence of the first pigment, and as a result, the ink is easily diffused in the lateral direction of the paper.

Also, since the first pigment tends to agglomerate more strongly than the second pigment, the second ink contains the second pigment.
In the case where a substance that destabilizes the dispersion stability of the pigment is included, "haze" is scarcely observed during the reaction between the second ink and the first pigment, and as a result, the dot diameter increases. Nevertheless, it is considered that the edge sharpness is improved.

In addition, as described above, a large dot diameter can be formed with a small amount of ink, and the amount of the polymer dispersant added to the third ink can be reduced with the use of the first pigment. In addition, the fixing property is further improved.

In the present embodiment, when the second ink has excellent permeability to a print medium,
The fixability and the dot diameter are further improved. This is because the second ink quickly permeates or diffuses into the print medium to form a kind of ink receiving layer on the surface of the print medium. The third ink applied subsequently to the second ink by the ink receiving layer reacts and quickly permeates and diffuses the ink into the print medium while reacting. As a result, large dots are quickly formed.

Further, in this embodiment, the use of the second ink in which the concentration of the substance that destabilizes the dispersion stability of at least one of the first pigment and the second pigment and the applied amount are optimized. Is preferable for further improving the image quality. If the concentration of the substance that destabilizes the dispersion stability of at least one of the first pigment and the second pigment is about 1/3 of the pigment concentration in the third ink, the OD becomes sufficiently high, It is not necessary to increase the concentration more than necessary. In addition, the lower the concentration of the substance that destabilizes the dispersion stability of at least one of the first pigment and the second pigment is lower than the pigment concentration, the more favorable the fixing property.

With respect to the application amount of the second ink having the function as the processing liquid, the amount of the second ink is 1/8 to 3 times that of the third ink.
に す る is preferable because OD and edge sharpness are improved.

As described above, by superimposing the second ink on the third ink later or in advance so as to be in contact with the third ink, the OD is higher, the haze is less, and the fixability is improved by the respective mechanisms. Also, it is possible to form an extremely high-quality image on a print medium in a short fixing time.

For example, a second ink (first ink) having a function as a processing liquid according to an embodiment common to the present invention.
Containing the same kind of ionic dye as the ink, and
A color ink having a dye concentration lower than that of the first ink and containing a substance that destabilizes the dispersion stability of at least one of the first pigment and the second pigment). By combining this with the third pigment ink, it is possible to obtain an image with a wide color reproduction range and little graininess at each gradation. In this case, the image quality can be further improved by using the same dye as the dye contained in the first ink for the second ink. Also the second
Since the dye concentration in the ink is low, the association between the first pigment and at least one of the second pigment and a substance that destabilizes the dispersion stability is small, and a more stable ink can be obtained. When the third ink is Bk ink, the image quality of Bk is improved, and a high-quality inkjet image can be obtained.

In the recording unit according to the present invention, each of the inks constituting the ink set is used for ink-jet recording, and an ink containing section containing these inks and a head section for ejecting each ink are provided. And a recording unit.

[0042] An ink cartridge according to the present invention is an ink cartridge comprising an ink storage section for storing each ink constituting the ink set.

Further, the ink jet printing apparatus according to the present invention comprises: an ink storage section for storing each ink included in the ink set described above; and a recording head for discharging each of these inks individually by an ink jet printing method. An inkjet printing apparatus comprising:

[0044]

DESCRIPTION OF THE PREFERRED EMBODIMENTS (First Embodiment)
(1) A first ink containing an anionic dye as a coloring material in an aqueous medium, and (2) a coloring material concentration lower than that of the first ink containing an anionic dye as a coloring material in an aqueous medium. And destabilizes the dispersion stability of at least one of the first pigment and the second pigment in the third ink when in contact with the third ink in a liquid state on a print medium. A second ink containing a substance, and (3) a first pigment, a second pigment, and a polymer dispersant for dispersing the second pigment, wherein the first pigment and the A second pigment is included in the ink in a dispersed state together with the first pigment, wherein the first pigment has at least one anionic group bonded directly or through another atomic group to the surface of the first pigment. Self-dispersible pigment, wherein the second pigment is added to the aqueous medium by a polymer dispersant. A pigment that can be dispersed, the polymer dispersant having one feature in that the third ink is at least one of an anionic polymer dispersant and a nonionic polymer dispersant. Is what it is.

The ink jet printing method according to the first embodiment of the present invention comprises: (1) a step of applying the first ink to a print medium by an ink jet method; (2)
Applying the second ink to the print medium by an inkjet method; and (3) applying the third ink to the print medium by an inkjet method, wherein the second step is the third step Subsequent to or substantially at the same time, the second ink and the third ink are brought into contact with each other in a liquid state on the print medium.

When the third ink is a black ink and the first and second inks are color inks, the area where the second ink and the third ink come into contact is determined by the black ink. By including the edge of the black image facing the boundary region between the black image and the color image by the color ink, it is possible to prevent bleeding between the black image and the color image, and it is effective to improve the quality of the color image. Become.

Hereinafter, each ink used in this embodiment will be described.

(First Ink) The first ink according to the present invention is preferably an aqueous ink containing an anionic dye. As the anionic dye, for example, a water-soluble dye used in an inkjet ink, for example, an acid dye, a reactive dye, a direct dye, a food dye, or the like can be used. As these anionic dyes, existing dyes or newly synthesized dyes may be used, and if an image is formed, most dyes can be used as long as an image having an appropriate color tone and density can be obtained. . It is also possible to use a mixture of any of these.

Hereinafter, specific examples of anionic dyes that can be used in other inks will be illustrated for each color tone of the ink.

(Coloring material for yellow) C.I. I. Direct Yellow: 8, 11, 12, 2
7, 28, 33, 39, 44, 50, 58, 85, 8
6, 87, 88, 89, 98, 100, 110; I. Acid Yellow: 1, 3, 7, 11, 1
7, 23, 25, 29, 36, 38, 40, 42, 4
4, 76, 98, 99; C.I. I. Reactive Yellow: 2, 3, 17, 2
5, 37, 42; I. Food yellow: 3.

(Coloring material for red) C.I. I. Direct Red: 2, 4, 9, 11, 2
0, 23, 24, 31, 39, 46, 62, 75, 7
9,80,83,89,95,197,201,21
8, 220, 224, 225, 226, 227, 22
8, 229, 230; I. Acid Red: 6, 8, 9, 13, 14,
18, 26, 27, 32, 35, 42, 51, 52, 8
0, 83, 87, 89, 92, 106, 114, 11
5, 133, 134, 145, 158, 198, 24
9, 265, 289; I. Reactive Red: 7, 12, 13, 1
5, 17, 20, 23, 24, 31, 42, 45, 4
6, 59; I. Food Red: 87, 92, 94.

(Coloring material for blue) C.I. I. Direct Blue: 1, 15, 22, 25,
41, 76, 77, 80, 86, 90, 98, 106,
108, 120, 158, 163, 168, 199, 2
26; I. Acid Blue: 1, 7, 9, 15, 22,
23, 25, 29, 40, 43, 59, 62, 74, 7
8, 80, 90, 100, 102, 104, 117, 1
27, 138, 158, 161; I. Reactive Blue: 4, 5, 7, 13,
14, 15, 18, 19, 21, 26, 27, 29, 3
2, 38, 40, 44, 100.

(Coloring material for black) C.I. I. Direct black: 17, 19, 22, 3
1, 32, 51, 62, 71, 74, 112, 113,
154, 168, 195; I. Acid Black: 2, 48, 51, 52,
110, 115, 156; I. Food black 1, 2.

The content of the coloring material contained in the ink is, for example, such that when the ink is used for ink-jet recording, the ink has excellent ink-jet ejection characteristics and has a desired color tone and density. May be appropriately selected, but as a guide, 3 to 5 with respect to the total weight of the ink.
A range of 0% by weight is preferred. The amount of water contained in the ink is preferably in the range of 50 to 95% by weight based on the total weight of the ink.

Further, examples of the solvent or dispersion medium used for preparing the ink include water or a mixed solvent of water and a water-soluble organic solvent. Examples of the water-soluble organic solvent 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; ethylene glycol and propylene glycol. , Butylene glycol, triethylene glycol,
1,2,6-hexanetriol, thiodiglycol,
Hexylene glycol, alkylene glycols such as diethylene glycol, lower alkyl ethers of polyhydric alcohols such as ethylene glycol methyl ether, diethylene glycol monomethyl ether and triethylene glycol monomethyl ether, ethanol, isopropyl alcohol, n-butyl alcohol, isobutyl alcohol and the like In addition to monohydric alcohols, glycerin, N-methyl-2-pyrrolidone, 1,3-dimethylimidazolidinone, triethanolamine, sulfolane, dimethyl sulfoxide and the like are used, and one or more of these may be used. it can. Although there is no particular limitation on the content of the water-soluble organic solvent, 2 to 5% by weight of the total weight of the second ink,
More preferably, 5 to 40% by weight is a suitable range.

When the first ink is applied to a recording medium by an ink-jet recording method (for example, a bubble jet (registered trademark) method), the color ink is coated with the above-described desired ink so as to have excellent ink-jet discharge characteristics. It is preferable to prepare so as to have a viscosity and a surface tension.

When the ink is, for example, a color ink, the Ka value obtained by the Bristow method, which is known as a measure of the permeability of the ink into a recording medium, is, for example, 5 (ml).・ M ^-2・ msec
^-1/2 ) is preferable because it can form a higher quality color image on a recording medium even when the third ink according to the present invention is a black ink. . That is, since the ink having such a Ka value has high permeability to the recording medium, for example, even when images of at least two colors selected from yellow, magenta, and cyan are recorded adjacent to each other, adjacent inks may be used. Color bleeding between images to be formed can be suppressed, and even when these inks are overprinted to form a secondary color image, the permeation of each ink is high, so that adjacent inks are different. The occurrence of bleeding with the color image can be effectively suppressed. As a method for adjusting the Ka value of the color ink to such a value, a conventionally known method such as addition of a surfactant to the ink or addition of a permeable solvent such as glycol ether can be applied. Of course, the amount of addition may be appropriately adjusted in consideration of the above-mentioned Ka value.

(Second Ink) The second ink is an aqueous medium.
An anionic dye in the body, and a third ink contained in the third ink.
Dispersion stability of at least one of the first pigment and the second pigment
Contains substances that destabilize. Instability of pigment dispersion stability
The term “stabilization” refers to, for example, aggregation, precipitation, or
And the like. Thickening refers to the two inks before mixing.
Here, the viscosity of either the third ink or the second ink)
When the viscosity of the ink mixed with both becomes higher than
Means a phenomenon. A small amount of the first pigment and the second pigment
At least one of the substances that destabilizes the dispersion stability
Is preferably a cationic polyvalent metal ion.
You. Examples of cationic polyvalent metal ions include C
a⁺⁺, Cu ⁺⁺, Ni⁺⁺, Mg⁺⁺, Zn⁺⁺⁺, Ba⁺⁺, A
l⁺⁺⁺, Fe⁺⁺⁺, Cr⁺⁺⁺, Co⁺⁺, Fe⁺⁺, La⁺⁺,
Nd⁺⁺⁺, Y⁺⁺⁺These are used alone in the ink.
It may be included, but a plurality of types may be included.

[0059] Representative and preferred anion capable of forming a salt in combination with the polyvalent metal ^ions, Cl -, NO ₃
^{-, I -, Br -,} ClO 3 -, CH 3 COO - it is not limited thereto.

The content of the polyvalent metal ion or its salt in the second ink described here is about 0.01 to 1 on a mass basis.
It is preferably 0%. A more preferable range of the salt concentration is 1 to 5%. A more preferable range of the salt concentration is 1 to 3.
%.

The second ink contains, in addition to an anionic dye and a substance that destabilizes the dispersion stability of at least one of the first pigment and the second pigment in the third ink, an aqueous medium. Including. This aqueous medium contains water alone or contains water and a water-soluble organic solvent, and may further contain other additives.

Examples of the water-soluble solvent 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, ethylene glycol, and the like. Alkylene glycols such as propylene glycol, butylene glycol, triethylene glycol, 1,2,6-hexanetriol, thiodiglycol, hexylene glycol, and diethylene glycol; ethylene glycol methyl ether; diethylene glycol monomethyl ether; triethylene glycol monomethyl ether; Lower alkyl ethers of polyhydric alcohols,
In addition to monohydric alcohols such as ethanol, isopropyl alcohol, n-butyl alcohol, and isobutyl alcohol, glycerin, N-methyl-2-pyrrolidone,
-Dimethylimidazolidinone, triethanolamine,
Sulfolane, dimethyl sulfoxide and the like are used, and one or more of these can be used. The content of the water-soluble organic solvent is not particularly limited, but is preferably 5 to 60% of the total mass of the second ink, more preferably 5 to 60%.
４０40%.

The anionic dye used in the second ink may be the same as the dye used in the first ink. However, it is possible to prevent the association with a polyvalent metal ion or the like at a higher level. C. I.
Acid yellow 23; I. Acid Red 52,
289; I. Acid Blue 9; I. Reactive Red 180; C.I. I. Direct Blue 189,
199 etc. can be mentioned as a preferable thing.

Further, a magenta dye represented by the following structural formula (I) can be preferably used. These dyes may be used alone or in combination of two or more. Further, since the second ink has a lower colorant density than that of the first ink, the probability of contact with polyvalent metal ions and the like is relatively low, and the degree of freedom in selecting a dye is wider. In addition, since the concentration of the polyvalent metal ion may be relatively low as described above, the degree of freedom in selecting the dye is higher.

[0065]

Embedded image (S = SO ₃ X; X is an alkali metal (eg, Na, Li
In this embodiment, it is necessary to adjust the second ink so as to have a high permeability to the print medium, to improve the fixing speed of the image dots to the print medium and to improve the fixability. It is preferable in order to improve.

(Third Ink) As an example of the third ink that can be used in the first embodiment, an ink containing a first pigment and a second pigment as coloring materials in a dispersed state in an aqueous medium is used. Wherein the first pigment is a self-dispersing pigment in which at least one anionic group is bonded to the surface of the first pigment directly or via another atomic group; The pigment is a pigment that can be dispersed in the aqueous medium by a polymer dispersant, and the ink further contains a polymer dispersant containing at least one of an anionic polymer dispersant and a nonionic polymer dispersant. The ink contains a second pigment as a dispersant for dispersing the pigment.

Hereinafter, each component of the ink will be sequentially described.

(First Pigment) A self-dispersible pigment is a pigment that is stably dispersed in water, a water-soluble organic solvent or a liquid obtained by mixing them without using a dispersant such as a water-soluble polymer compound. It refers to a pigment that maintains its state and does not cause agglomeration of pigments in the liquid that would interfere with normal ink ejection from the orifice using inkjet recording technology.

(Anionic Self-Dispersion CB) As such a pigment, for example, a pigment in which at least one anionic group is bonded to the pigment surface directly or via another atomic group is suitably used. Examples include those wherein carbon black has at least one anionic group attached to the surface, either directly or through another group.

Examples of such an anionic group bonded to carbon black include, for example, -COOM,
—SO ₃ M, —PO ₃ HM, —PO ₃ M _{2 and the} like (where M is a hydrogen atom, an alkali metal, ammonium, or
Represents an organic ammonium).

Examples of the alkali metal “M” include lithium, sodium, potassium and the like, and examples of the organic ammonium “M” include mono-trimethyl ammonium, mono-triethyl ammonium, and mono-trimethanol. Ammonium and the like.

Among these anionic groups, particularly, -CO
OM or -SO ₃ M because a large effect of stabilizing the dispersion state of the carbon black preferred.

Incidentally, it is preferable to use the above-mentioned various anionic groups bonded to the surface of carbon black via another atomic group. Examples of the other atomic group include a linear or branched alkylene group having 1 to 12 carbon atoms, a substituted or unsubstituted phenylene group, and a substituted or unsubstituted naphthylene group. Here, examples of the substituent that may be bonded to the phenylene group or the naphthylene group include a linear or branched alkyl group having 1 to 6 carbon atoms.

Specific examples of the anionic group bonded to the surface of carbon black via another atomic group include, for example, -C ₂ H ₄ COOM, -PhSO ₃ M, -PhCOO
M and the like (provided that Ph represents a phenyl group, and M is defined as above), but of course is not limited thereto.

As described above, carbon black having an anionic group bonded to the surface directly or via another atomic group can be produced, for example, by the following method.

That is, -COON is applied to the carbon black surface.
As a method for introducing a, for example, a method of oxidizing commercially available carbon black with sodium hypochlorite may be mentioned. Further, for example, -Ar-C
As a method of bonding an OONa group (where Ar represents an aryl group), a method of forming a diazonium salt in which nitrous acid is allowed to act on an NH ₂ —Ar-COONa group and bonding the diazonium salt to the surface of carbon black may, of course, be mentioned. However, the present invention is not limited to this.

By the way, 80% or more of the self-dispersion type pigment (first pigment) to be contained in the ink according to this embodiment is 0.05 to 0.3 μm, particularly 0.1 to 0.25 μm.
Preferably, the particle size is m. Such an ink adjustment method is as described in detail in the embodiments described later.

(Second Pigment) The second pigment which can be used in the ink of the present embodiment is dispersed in a dispersion medium of the ink, specifically, for example, an aqueous medium by the action of a polymer dispersant. And pigments that can be used. That is, a pigment that can be stably dispersed in an aqueous medium only as a result of the adsorption of the polymer dispersant on the surface of the pigment particles is suitably used. Examples of such a pigment include carbon black pigments such as furnace black, lamp black, acetylene black, and channel black. As specific examples of such a carbon black pigment, for example, the following can be used alone or in an appropriate combination.

Carbon black pigments: Raven 7000, Raven 57
50, Ray-Van 5250, Ray-Van 5000ULT
RA, Ray-Van 3500, Ray-Van 2000, Ray-Van 1500, Ray-Van 1250, Ray-Van 12
00, Ray-Van 1190ULTRA-II, Ray-Van 1170, Ray-Van 1255 (all manufactured by Columbia); Black Pearls L, Legal (Re
gal) 400R, legal 330R, legal 660
R, Mogul L, Monarch 700,
Monak 800, Monak 880, Monak 900, Monak 1
000, Monak 1100, Monak 1300, Monak 14
00, Valcan XC-72R (above manufactured by Cabot); Color Black FW1, color black
FW2, Color Black FW2V, Color Black 18, Color Black FW200, Color Black S150, Color Black S160, Color Black S170, Printtex (Printe
x) 35, PRINTEX U, PRINTEX V, PRINTEX 140U, PRINTEX 140V, Special Black 6, Special Black 5, Special Black 4A, Special Black 4
No. 25, No. 33, No. 40, No. 47, No. 52, No.
900, No. 2300, MCF-88, MA600, M
A7, MA8, MA100 (all manufactured by Mitsubishi Chemical Corporation).

Examples of other black pigments include magnetic fine particles such as magnetite and ferrite, and titanium black.

In addition to the above-mentioned black pigments, blue pigments, red pigments and the like can be used.

The amount of the color material including the first and second pigments is 0.1 to 15% by weight, more preferably 1 to 10% by weight, based on the total amount of the ink. The ratio of the first pigment to the second pigment is 5/95 to 97/3, more preferably 10/95 to 97/3.
The range of / 90 to 95/5 is preferred. More preferably, the ratio of the first pigment / the second pigment is 4/6 to 9/1.
Another more preferred range is a range in which the first pigment is more than the second pigment. When the amount of the first pigment is large, not only the dispersion stability as the ink but also the ejection stability of the head, especially the stability including the ejection efficiency and the reliability due to the small wetting of the ejection port surface are exhibited. Is done.

Further, the behavior of the ink on the paper is such that the ink having a small amount of the second pigment adsorbed with the polymer dispersant effectively spreads the ink on the surface of the paper. Is formed, and the scratch resistance of the image is also improved by the effect.

The polymer dispersant for dispersing the second pigment in the aqueous medium is, for example, adsorbed on the surface of the second pigment and
A pigment having a function of stably dispersing the above pigment in an aqueous medium is preferably used. Examples of such polymer dispersants include anionic polymer dispersants and nonionic polymer dispersants.

(Anionic Polymer Dispersant) A polymer of a monomer as a hydrophilic group and a monomer as a hydrophobic group and a salt thereof are exemplified. Specific examples of the monomer as a hydrophilic group include, for example, styrene sulfonic acid, α, β-
Ethylenically unsaturated carboxylic acid, α, β-ethylenically unsaturated carboxylic acid derivative, acrylic acid, acrylic acid derivative,
Examples include methacrylic acid, methacrylic acid derivatives, maleic acid, maleic acid derivatives, itaconic acid, itaconic acid derivatives, fumaric acid, and fumaric acid derivatives.

Specific examples of the monomer as a hydrophobic group include styrene, styrene derivatives, vinyl toluene, vinyl toluene derivatives, vinyl naphthalene, vinyl naphthalene derivatives, butadiene, butadiene derivatives, isoprene, isoprene derivatives, ethylene, ethylene Derivatives, propylene, propylene derivatives, alkyl esters of acrylic acid, alkyl esters of methacrylic acid, and the like.

The cationic counter ions for forming the above-mentioned polymer salts include hydrogen ions, alkali metal ions, ammonium ions, organic ammonium ions, phosphonium ions, sulfonium ions, oxonium ions, and styrene ions. Examples include, but are not limited to, onium compounds such as bonium ions, stannonium, and iodonium. Also,
In the above polymer and its salts, polyoxyethylene group, hydroxyl group, acrylamide, acrylamide derivative, dimethylaminoethyl methacrylate, ethoxyethyl methacrylate, butoxyethyl methacrylate, ethoxytriethylene methacrylate, methoxypolyethylene glycol methacrylate, vinylpyrrolidone, vinylpyridine, vinyl Alcohols and alkyl ethers may be appropriately added.

(Nonionic Polymer Dispersant) Examples of the nonionic polymer dispersant include polyvinylpyrrolidone, polypropylene glycol, vinylpyrrolidone-vinyl acetate copolymer and the like.

The above-mentioned first pigment, second pigment and polymer dispersant are appropriately selected in combination and dispersed and dissolved in an aqueous medium to obtain the third ink according to the present invention. Although it is possible to use a self-dispersing pigment in which at least one anionic group is bonded to the surface of the pigment directly or via another atomic group as the first pigment, a polymer dispersant may be used. By combining and containing at least one selected from an anionic polymer dispersant and a nonionic polymer dispersant, good ink stability can be ensured.

The ratio of the second pigment and the polymer dispersant for dispersing the second pigment in the third ink was 5: 0.5 by mass.
~ 5: 2 is preferred, but not limited thereto.

(Aqueous Medium) As the aqueous medium serving as the dispersion medium of the first and second pigments, water alone or a medium containing water and a water-soluble organic solvent is used. Examples of the water-soluble organic solvent include carbon numbers such as methyl alcohol, ethyl alcohol, n-propyl alcohol, isopropyl alcohol, n-butyl alcohol, sec-butyl alcohol, tert-butyl alcohol, isobutyl alcohol, and n-pentanol. Amides such as dimethylformamide and dimethylacetamide; ketones or ketoalcohols such as acetone and diacetone alcohol; ethers such as tetrahydrofuran and dioxane; diethylene glycol, triethylene glycol, tetraethylene glycol, and diethylene glycol; Oxyethylene or oxypropylene copolymers such as propylene glycol, tripropylene glycol, polyethylene glycol and polypropylene glycol; Alkylene glycols having an alkylene group containing 2 to 6 carbon atoms, such as coal, propylene glycol, trimethylene glycol, triethylene glycol, 1,2,6-hexanetriol; glycerin; ethylene glycol monomethyl (or ethyl) ether; Lower alkyl ethers such as diethylene glycol monomethyl (or ethyl) ether and triethylene glycol monomethyl (or ethyl) ether; lower alkyl polyols such as triethylene glycol dimethyl (or ethyl) ether and tetraethylene glycol dimethyl (or ethyl) ether Dialkyl ethers; alkanolamines such as monoethanolamine, diethanolamine and triethanolamine; sulfolane, N-methyl-2-pyrrolidone, 2-pyrroline Don, 1,3-dimethyl-2-imidazolidinone. These water-soluble organic solvents can be used alone or as a mixture.

(Permeability of Third Ink into Recording Medium) The ink of the present embodiment containing the above-described various components has a Ka value of 1 (ml) by focusing on the permeability to the print medium.・^{M -2}・ msec ^-1/2 ), when used together with the processing solution described later, it has an extremely uniform density, sharp edges, and a high fixing speed and fixability to print media. Excellent image dots can be obtained. Hereinafter, the permeability of the ink to the print medium will be described.

When the permeability of the ink is represented by the amount of ink permeation V per m ² (unit: milliliter / m ² = μm) at time t after the ejection of the ink droplet, V is the following Bristow It is known to be represented by a scheme. V = Vr + Ka (t-tw) ^1/2 (where t> tw) Immediately after the ink droplet has dropped on the surface of the print medium, the ink droplet is absorbed in the uneven portion of the surface (the surface roughness of the print medium). Is hardly permeated into the print medium. The time during that time is tw (wet time), and the amount of absorption into the uneven portion during that time is Vr.
When the elapsed time after the drop of the ink droplet exceeds tw, the permeation amount V increases by an amount proportional to the half power of the exceeded time (t-tw). Ka is a proportional coefficient of this increase, and shows a value corresponding to the permeation speed.

The Ka value was measured using a liquid dynamic permeability tester S (manufactured by Toyo Seiki Seisakusho) by the Bristow method. In this experiment, the applicant's Canon Inc.
Paper B was used as a print medium (recording paper). This P
The B sheet is a recording sheet that can be used for both a copying machine and an LBP using an electrophotographic method and a print using an ink jet recording method.

Similar results were obtained for PPC paper, which is an electrophotographic paper of Canon Inc.

The Ka value is determined by the type of surfactant, the amount added, and the like. For example, ethylene oxide
2,4,7,9-tetramethyl-5-decyne-4,7-
Diol (ethylene oxide-2,4,7,9-tetramethyl-5-dec
By adding a nonionic surfactant called yen-4,7-diol (hereinafter referred to as “acetylenol” (manufactured by Kawaken Fine Chemical Co., Ltd.)), the permeability increases.

In the case of an ink in which acetylenol is not mixed (content is 0%), the ink has low permeability and has properties as an additional ink defined later. When acetylenol is mixed at a content of 1%, it has the property of penetrating into the recording paper in a short time, and has the property of a highly permeable ink which will be specified later. An ink in which acetylenol is mixed at a content of 0.35% has a property as a semi-permeable ink that is intermediate between the two.

[0098]

[Table 1] Table 1 above shows the Ka for each of the “additional ink”, “semi-permeable ink”, and “highly permeable ink”.
Value, acetylenol content (%), surface tension (mN / m)
Is shown. The greater the Ka value, the higher the permeability of each ink to recording paper as a print medium. That is, the smaller the surface tension, the higher the surface tension.

The Ka values in Table 1 were measured using the liquid dynamic permeability tester S (manufactured by Toyo Seiki Seisakusho) by the Bristow method as described above. In the experiment, the above-mentioned PB paper from Canon Inc. was used as the recording paper. Similar results were obtained with the above-described Canon PPC paper.

Here, the ink of the system defined as “highly permeable ink” has an acetylenol content of 0.7% or more, and is in a range in which good results are obtained in terms of permeability. As a criterion of the permeability to be carried by the ink of the present embodiment, the Ka value of the “additional ink”, that is, less than 1.0 (ml · m ⁻² .msec ^−1/2 ) is preferable. Is preferably 0.4 (mlm- ² msec- ^{1 / 2} ) or less.

(Addition of Dye) A dye may be further added to the third ink of the above embodiment. That is, the first pigment, the second pigment
An ink containing a pigment and an ink containing a dispersant for dispersing the second pigment in an aqueous medium and further adding a dye can print excellent image dots in a short fixing time by being used in combination with the second ink. It can be formed on a medium. As described above, the cohesive force of the second pigment is reduced by the presence of the first pigment. However, the cohesive force of the second pigment is further reduced by the addition of the dye. It is considered that unevenness of a printed image such as "crack" which is likely to occur on a recording medium having poor absorbency of plain paper or the like can be effectively suppressed. Preferred dyes include anionic dyes.

(Anionic Dye) As the anionic dye soluble in the aqueous medium that can be used in the present embodiment as described above, known acid dyes, direct dyes, and reactive dyes are preferably used. You. It is particularly preferable to use a dye having a disazo or trisazo skeleton structure as the skeleton structure. It is also preferable to use two or more dyes having different skeleton structures. As a dye to be used, a dye such as cyan, magenta, and yellow may be used as long as the color tone does not largely differ from the dye other than the black dye.

(Dye Addition Amount) The dye may be added in an amount of 5% by mass to 60% by mass of the entire coloring material contained in the third ink. Considering that the effects of mixing can be used more effectively,
Preferably, it is less than 50% by mass. Further, when the ink is used with an emphasis on the printing characteristics on plain paper, 5% by mass or more
It is preferably 30% by mass.

(Second Embodiment) In a second embodiment of the ink jet printing method according to the present invention, the first to third inks described above are used, and (1) the first ink is applied by the ink jet method. A first step of depositing the second ink on the print medium using an inkjet method; and (3) a second step of depositing the second ink on the print medium using the inkjet method.
A third step of depositing a third ink on the print medium using an ink-jet method, the third step comprising:
Following the second step, the second step is performed on the print medium.
And the third ink are in contact with each other in a liquid state, and only the order of applying the second ink and the third ink is different from that of the first embodiment.

The order in which the third ink and the second ink (processing liquid) are applied to the print medium in this embodiment is basically the same as described above, after the second ink is applied to the print medium. If the order is such that the third ink is applied, the above-described predetermined effect can be obtained. Regarding a specific configuration for determining the order of application, for example, when a serial type head is used, the above-described order may be realized by performing a plurality of scans on the same area across the paper feed. Are included in the range.

As described above, the third ink of the present embodiment is applied subsequent to the application of the second ink to the print medium, but the number of applied inks is not limited to one drop. . For example, following the application of the second ink, two drops of the third ink may be applied,
In that case, of these two drops, preferably, the ink applied earlier has a larger proportion of the second pigment than the first pigment, and the ink applied thereafter is more conversely the first pigment. The proportion can be higher than that of the second pigment.

As described above, when a plurality of ink droplets are applied, it is preferable that the total amount of the applied ink is substantially equal to that when one droplet is applied. In other words, according to this embodiment, when the ink is divided into a plurality of portions and the ink is applied, the above-described predetermined effect can be obtained even if the amount of each droplet decreases according to the number of divisions.

Next, the time difference between the application of the second ink and the application of the third ink in the present embodiment is basically the same as the application order described above, as long as the respective effects of the present embodiment described above basically appear. Even a long time difference is included in the scope of the present invention.

That is, the reaction between the third ink and the second ink occurs in various modes depending on the time from when the second ink is applied to when the third ink is applied.
For example, even when the time is short, a sufficient reaction between the pigment and the like and the second ink occurs at the peripheral portion of the dot formed by overlapping them, that is, at the edge portion, and each effect of the present embodiment, particularly, It has also been observed that at least the effect of suppressing the "" can be produced.

From such a point, in the present specification, the “reaction” between the third ink and the second ink means not only an overall reaction but also a reaction at a part such as an edge portion. And In addition, the case where the reaction occurs after permeating into the print medium is included. Further, in the present invention, all of these reaction modes are "contact in a liquid state".
Is defined as belonging to the category.

Further, as a more specific configuration of such a configuration, a so-called full multi-type print head in which ink ejection ports are arranged in a range corresponding to the entire width of a print area of a print medium to be conveyed, or a print medium On the other hand, any of the serial type print heads that move for scanning can apply the above-described ink according to the present invention.

As the ink ejection system of the print head which can be used in the first and second embodiments of the printing method described above, any of the well-known systems such as a piezo system can be adopted, but the most preferable form is used. Is a method in which bubbles are generated in ink using thermal energy, and the ink is ejected by the pressure of the bubbles.

Further, since the overlapping range where ink is ejected by each print head is usually controlled in units of pixels constituting a print image or the like, the ink or the like is ejected and overlapped at the same position. However, application of the present invention is not limited to such a configuration. For example, a configuration in which some of the dots of ink overlap with each other to produce the predetermined effect of the present embodiment, or a method in which the second ink is thinned out and applied to the data of each pixel and flows in from adjacent pixels due to bleeding or the like. A configuration in which the second ink reacts with the pigment and the like in the third ink is also included in the scope of the present invention.

Hereinafter, the first and second aspects of the above printing method will be further described with reference to the drawings, using specific examples.

In the first and second embodiments of the present invention, when printing a character or the like by using the third ink as black ink, for example, all or all of the pixels to which the black ink is applied are printed. Cyan (hereinafter, also referred to as “light C”) ink as a second ink having a low color density is partially applied. The Bk ink is made anionic, and the light C ink contains a substance that destabilizes the dispersion stability of the pigment in the Bk ink, so that when the Bk ink and the light C ink are mixed on a print medium, It causes coagulation and precipitation of the material, or increases the viscosity of the ink.

When the light C ink realizing such a high OD is used, the higher the color material density of the light C ink, the more
The OD of the black dot formed by the light C ink and the Bk ink is high. As a result, when a predetermined OD is to be obtained for a black dot, the ejection amount of the Bk ink can be reduced by increasing the density of the light C ink. However, if the density of the light C ink is too high, the OD due to the light C ink exceeds the range of 0.2 to 0.6, and the deviation becomes noticeable.

The application of such a low OD of 0.2 to 0.6 to the dots by the light C ink means that the dye concentration is relatively thin such as 0.5% by mass or 1% by mass with respect to the total amount of the ink. This can be realized by using ink. As described above, the concentrations of 0.5% by mass and 1% by mass are respectively 1/6 and 1 / D of the dye concentration of the normally used C ink.
In this specification, the ink having a density of 3 is referred to as “light ink”. Further, when two inks of different densities are used for the inks of the same color as described later, the density is relatively low, and the ink used in superposition with the Bk ink is also referred to as “light ink”.

Next, an ink jet printer using a combination of the above-described Bk ink and a light ink containing a polyvalent metal salt which is applied in an overlapping manner will be described.

FIGS. 4A to 4D are diagrams schematically showing the arrangement of print heads in such an ink jet printer. These figures show the full line type print head from the side with respect to the paper feed direction, but the combination of print heads shown in each figure is
The present invention is not limited to such a full line type, and it is a matter of course that a combination of serial type print heads arranged on the carriage as shown in the respective drawings may be used.

In the arrangement shown in FIG. 4A, Bk ink, light C ink, C ink, magenta (hereinafter simply referred to as "M") ink, and yellow (hereinafter simply referred to as "M") are arranged in this order from the upstream side in the paper feeding direction. Y) are also ejected. In this configuration, the first ink is the Y ink, the M ink, and the C ink, the second ink is the light C ink, and the third ink is the Bk ink.

In this case, when printing black characters or the like, as described above, the discharge of the light C ink from the light C head is superimposed on the discharge of the Bk ink from the Bk head. In this case, the concentration of the dye of the light C ink is 0.1.
In the case where the ejection positions of the light C ink and the Bk ink are displaced from each other, the displacement between the ink dots becomes inconspicuous. be able to. In addition, this light C
The color material density of the ink corresponds to 1 / 2.5 to 1/6 of the color material density of the C ink used in this printer.

The light C ink has an anionic dye in the same manner as the Bk ink and other Y, M, and C inks contain an anionic dye.
On the other hand, it has a polyvalent metal salt, which causes insolubilization or aggregation of the pigment in the Bk ink when the Bk ink and the light C ink are superimposed, thereby improving the density of the Bk ink dots and reducing other feathering. And a predetermined effect such as improvement in water resistance can be obtained.

Further, the light C ink and the C ink can be applied in a predetermined reproduction density range in order to reduce graininess and realize a smooth gradation change particularly in a low density portion of a print image. Will be This is because, using a predetermined density distribution table, if the input density data for cyan is relatively small, this is converted into light C ink density data in accordance with the value. This can be realized by distributing the data to the density data of each of the ink and the C ink and converting the density data to the density data of the C ink as the value of the input density data increases. When such a configuration is adopted, the OD of the light C ink by solid printing is:
It is preferable that the OD of the C ink is about １ ／ of that of the C ink. As described above, the concentration is desirably in the range of 1 / 2.5 to 1/6.

FIG. 4B shows a reference head arrangement of a printer that performs black-and-white monochrome printing, and printheads of Bk ink and light C ink are used in combination.

The configuration shown in FIG. 4C uses low-density blue (hereinafter simply referred to as “B”), that is, light blue, instead of the light C ink shown in FIG. By using a blue color ink that is the same system as C, it is possible to obtain substantially the same effect as when the light C ink is overlaid on the Bk ink. The blue ink is an ink containing a blue or cyan color material as a main color material as described above, but includes a cyan ink dye and a magenta ink dye. Is particularly preferable in terms of reducing color reproducibility and graininess.

In the examples shown in FIGS. 4A, 4C and 4D, the ink to be superimposed on the Bk ink is the light C ink or the same system light B ink, but the ink is superimposed. The type of the light ink is not limited to these.
For example, even if M or Y light inks are used, if the OD realized by their color material densities is appropriately determined, it is possible to perform printing with less noticeable dot shift. However, in the dot shift, the C or B ink dot has a relatively low brightness and is closer in color to the Bk ink dot.
It is preferable to use ink. Further, from the viewpoints of browning due to the insolubilization of the dye used in the Bk ink and the color tone of the pigment being slightly reddish, cyan and blue, which are complementary colors of red, are preferable from the viewpoint of correcting the color tone and improving the reflection density associated therewith. . In addition, from the viewpoint of reducing the graininess when performing other color printing, the C ink or the B ink has a relatively low brightness as described above, so that the graininess tends to appear remarkably. It is more preferable to reduce the graininess by using a light ink as the ink from the viewpoint of improving print quality.

[0127]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Specific examples of the above embodiment will be described below with reference to reference examples and drawings. The present invention is not limited to such embodiments, but can be further combined or applied to technologies in other fields that include similar problems. (Embodiment 1) FIG. 5 is a side view showing a schematic configuration of a full-line type printing apparatus according to a first embodiment.

This printing apparatus 1 prints by discharging ink from a plurality of full-line type print heads arranged at predetermined positions along the transport direction of a recording medium as a print medium (the direction of arrow A in the figure). The operation is controlled by a control circuit shown in FIG. 6, which will be described later.

Each print head 10 of the head group 101g
1Bk, 101C ', 101C, 101M and 101
In each of Y, about 7200 ink ejection ports are arranged at a density of 600 dpi in a width direction (a direction perpendicular to the paper surface of the drawing) of the recording paper conveyed in a direction A in the drawing, and a maximum of A3 size recording paper is formed. Printing can be performed.

The recording paper 103 is conveyed in the direction A by the rotation of a pair of registration rollers 114 driven by a conveyance motor, guided by a pair of guide plates 115, and registered at the leading end thereof. Belt 111
Conveyed by The transport belt 111, which is an endless belt, is held by two rollers 112 and 113.
4 When the roller 113 is driven to rotate, the recording paper 103 is conveyed. The recording paper 113 is attracted to the transport belt 111 by electrostatic attraction. The roller 113 is rotatably driven by a driving source such as a motor (not shown) in a direction for transporting the recording paper 103 in the direction of arrow A. The recording paper 1 conveyed on the conveyance belt 111 and during which recording was performed by the recording head group 101g
03 is discharged onto the stocker 116.

The print heads of the recording head group 101g include a head 101Bk for discharging the Bk ink described in the above embodiment, a head 101C ′ for discharging the light C ink containing a polyvalent metal salt, a C ink, an M ink, Heads 101C, 101M, and 10 that respectively discharge Y ink
1Y is arranged as shown in the figure along the transport direction A of the recording paper 103. By discharging ink of each color by each print head, printing of black characters and color images becomes possible. Here, as for the black image, the light C ink is ejected on the Bk ink as described in the above embodiment.

FIG. 6 is a block diagram showing a control configuration of the full line type printing apparatus 1 shown in FIG.

The system controller 201 includes a microprocessor, a ROM for storing a control program to be executed by the apparatus, a RAM used as a work area when the microprocessor performs processing, and the like. Execute The motor 204 is the driver 20
The driving of the roller 11 is controlled via the roller 11 shown in FIG.
3 is rotated to convey the recording paper.

The host computer 206 transfers information to be printed to the printing apparatus 1 of this embodiment,
The printing operation is controlled. The reception buffer 207
Data from the host computer 206 is temporarily stored, and stored until data is read by the system controller 201. The frame memory 208 is a memory for expanding data to be printed into image data, and has a memory size necessary for printing. In this embodiment, the frame memory 208 is described as being capable of storing one sheet of recording paper, but the present invention is not limited by the capacity of the frame memory.

The buffer 209P temporarily stores data to be printed, and has a storage capacity corresponding to the number of print heads and the number of discharge ports. The print control unit 210 is for appropriately controlling the drive of the print head in accordance with a command from the system controller 201. The print control unit 210 controls the drive frequency, the number of print data, and the like. The data for discharging the light C ink to be superimposed on the light C is also created and added to the light C data as an image. Drivers 211 are print heads 101Bk, 101C ', 101 for ejecting respective inks.
C, 101M, and 101Y are driven for ejection.
It is controlled by a signal from the print control unit 210.

In the above configuration, print data is transferred from the host computer 206 to the reception buffer 207 and is temporarily stored. Next, the stored print data is read by the system controller 201 and expanded in the buffer 209P. Further, paper jam, out of ink, out of paper, and the like can be detected by various detection signals from the abnormality sensor 222.

The print control unit 210 includes a buffer 209
Based on the Bk ink data among the image data developed on P, data for ejecting the light C ink is created and stored in the buffer 209P. Thus, in the buffer 209P, the OR data of the light C ink data when forming the black dot and the light C ink data when forming the cyan dot when used in combination with or independently of the C ink. Will be stored.
The ejection operation of each print head is controlled based on the print data in the buffer 209P developed in this manner.

FIG. 7 is a flowchart showing a process for generating the ejection data of the light cyan (C ') ink described above.
Light cyan ejection data is stored in the buffer 209 shown in FIG.
It is generated based on the ejection data of Bk ink stored in P. In other words, the buffer 209P stores bitmap data for one page obtained by further performing binarization processing on image data on which predetermined image processing has been performed, for C, light C, M,
It is stored for each color of Y and Bk. On the other hand, in this processing, light cyan ejection data to be superimposed on the Bk ejection data is created at a thinning rate of 50%. The dye concentration of light cyan used in the present embodiment is 1%, and the OD of the pattern itself is 0.4 when a thinning pattern of 50% is printed using the ink of this concentration. is there. In this embodiment, since a full-line type head is used, data for one page is created in advance from the viewpoint of printing speed and the like.

When this process is started, first, parameters X and Y indicating the pixel position are initialized (step S).
11). Here, X indicates a pixel position corresponding to the arrangement direction of the ejection openings in the head, while Y indicates a pixel position corresponding to the transport direction of the print medium. Next, in step S12, it is determined whether the ejection data PBk (X, Y) of the Bk ink is "1" (ejection) or "0" (non-ejection) for the position X, Y of the pixel to be processed. , "1",
In step S13, the light cyan ejection data PC '(X-
Similarly, it is determined whether or not (1, Y) is “1” (ejection) or “0” (non-ejection). Light cyan ejection data PC '(X, Y-1) at the pixel position is "1" (ejection) or "0".
(Non-discharge) is determined. If it is determined to be "0", the light cyan ejection data PC '(X, Y) at the target pixel position is set to "1", that is, ejection data in step S15.

The above processing is performed by calculating the number m of pixels in one row in the X direction.
And the number n of lines for one page (steps S16 to
Step S19), this process ends. By this process, light cyan ink is ejected in a so-called checker pattern onto pixels forming characters, images, and the like printed with black ink, and printing is performed on the black image with light cyan at a thinning rate of approximately 50%. It can be performed.

The image processing and the binarization processing including the processing shown in FIG. 7 described above are performed in the printer in the above embodiment, but the invention is not limited to this. Of course, it may be executed by a printer driver.

In the above-described embodiment, all the black images and the like are used when the light cyan ink is applied over the black ink. However, for example, characters such as characters requiring particularly high OD values are printed. Only when the light cyan ink is applied, the light cyan ink may be applied in an overlapping manner.

In this embodiment, as for the black ink discharged from the head 101Bk, an ink having a low permeation speed (hereinafter, referred to as “additional ink” in this embodiment) is used, and the heads 101C ′, 101C, 101M, and 101 are used.
The light cyan, cyan, magenta, and yellow inks respectively ejected from Y are inks having a high penetration speed (hereinafter, referred to as “highly permeable inks” in this embodiment).
Is used.

As described above, it can be said that the greater the content of acetylenol, the greater the amount of ink permeated with respect to the elapsed time, and the higher the permeability.

Here, it is known that as a condition when a surfactant is contained in a certain liquid, there is a critical micelle concentration (CMC) of the surfactant in the liquid. The critical micelle concentration is the concentration at which the concentration of the surfactant solution increases and several tens of children rapidly associate to form micelles. The acetylenol contained in the above-described ink for adjusting the permeability is a type of surfactant, and the acetylenol also has a critical micelle concentration depending on the liquid.

The relationship with the surface tension when the content ratio of acetylenol is adjusted has a relationship such that the surface tension does not decrease when micelles are formed. This indicates that the critical micelle concentration of acetylenol with respect to water is high. (CMC) was confirmed to be about 0.7%.

Correlating the critical micelle concentration with the above-mentioned Table 1, for example, the “highly permeable ink” defined in Table 1 contains acetylenol in a proportion higher than the critical micelle concentration (CMC) of acetylenol in water. It turns out that it is ink.

The compositions of the light C ink and the other inks used in this embodiment are as follows, and are produced by adding a solvent to each colorant. The ratio of each component is shown in parts by weight, and the total of each component is 100 parts by weight (Tables 3 to 3).
13).

[0149]

[Table 2]

[0150]

[Table 3]

[0151]

[Table 4]

[0152]

[Table 5]

[0153]

[Table 6] As apparent from the composition of the black ink, a pigment without a dispersant and a pigment with a polymer dispersant are used as coloring materials, and the pigment dispersion is as follows. [Pigment dispersion liquid 1] To a solution of 5 g of concentrated hydrochloric acid in 5.3 g of water, 1.58 g of anthranilic acid was added at 5 °. This solution was constantly kept at 10 ° C. or lower by stirring in an ice bath, and a solution obtained by adding 1.78 g of sodium nitrite to 8.7 g of water at 5 ° C. was added. Further, after stirring for 15 minutes, the surface area was 320 m ² / g and the DBP oil absorption was 1
20 ml of carbon black (20 ml / 100 g) was added in a mixed state. Thereafter, the mixture was further stirred for 15 minutes.
The obtained slurry was applied to Toyo Filter Paper No. After filtration with 2 (manufactured by Advantis), the pigment particles were sufficiently washed with water and dried in an oven at 110 ° C., and water was added to the pigment to prepare an aqueous pigment solution having a pigment concentration of 10% by weight. According to the above method, as represented by the following formula, a pigment dispersion in which anionic charged self-dispersible carbon black having a hydrophilic group bonded through a phenyl group was dispersed on the surface was obtained.

[0154]

Embedded image [Pigment dispersion liquid 2] Pigment dispersion liquid 2 was prepared as follows. Styrene-acrylic acid-ethyl acrylate copolymer (acid value 180, average molecular weight 12
000) 14 parts, monoethanolamine 4 parts and water 72
The parts are mixed and heated to 70 ° C. in a water bath to completely dissolve the resin component. At this time, if the concentration of the resin to be dissolved is low, the resin may not be completely dissolved. Therefore, when dissolving the resin, a high-concentration solution may be prepared in advance and diluted to prepare a desired resin solution. To this solution, 10 parts of carbon black (trade name: MCF-88, pH 8.0, manufactured by Mitsubishi Chemical Corporation) that can be dispersed in an aqueous medium for the first time by the action of a dispersant was added, and premixing was performed for 30 minutes.
Next, the following operation is performed to obtain carbon black (MCF
-88) was dispersed in an aqueous medium with a dispersant to obtain a pigment dispersion liquid 2. Dispersing machine: Side grinder (made by Igarashi Kikai) Grinding media: zirconia beads 1 mm diameter Filling rate of grinding media: 50% (volume) Grinding time: 3 hours Centrifugation treatment (12000 RPM, 20 minutes) It is clear from the above compositions. Thus, depending on the content of acetylenol, the black ink is added to the base ink,
C ′ (light C) and C, M, and Y inks are respectively set as high-penetration inks.

The color material density of the light C ink is 1% by weight, which is 1/3 of the color material density of the C ink, whereby the OD when the light C ink is solid-filled is about 0.1%. 57. In the present embodiment, the ejection data of the light C ink is thinned out at a thinning rate of 50% with respect to that of the Bk ink, and the OD of the pattern is set to about 0.
4 is assumed. Accordingly, even if the displacement of the ejection position of the Bk ink and the light C ink is about 200 m in the apparatus of this embodiment, the displacement can be made inconspicuous, and
The density of k ink dots was high and the sharpness was good.

There is no problem if the ejection position shift is 100 m without thinning out the light C data, and the OD of the Bk pixel increases. Therefore, one of them can be selected according to the degree of the shift occurring in the apparatus.

In this embodiment, the ink ejection ports of each print head are arranged at a density of 600 dpi, and printing is performed at a dot density of 600 dpi in the recording paper transport direction. As a result, the dot density of an image or the like printed in this embodiment becomes 600 dpi in both the row direction and the column direction. The ejection frequency of each head is 4
KHz, so the recording paper transport speed is about 170 m.
m / sec. Further, a distance Di between the head 101Bk and the light C ink head 101C '(see FIG. 5).
Is 40 mm, and therefore, the time from when the black ink is ejected to when the light C ink is ejected is about 0.1 sec. The discharge amount of each print head is about 18 pl per discharge.

The full-line type printing apparatus described above is used in a state where the print head is fixed in the printing operation, and the time required for transporting the recording paper is almost the time required for printing. It is a thing. Therefore, by applying the present invention to such a high-speed printing apparatus, the high-speed printing function can be further improved and high-quality printing can be performed.

The printing apparatus according to the present embodiment is most generally used as a printer, but is not limited to this, and it is needless to say that the printing apparatus can be configured as a printing unit such as a copying apparatus or a facsimile.

(Embodiment 2) FIG. 8 is a schematic perspective view showing the configuration of a serial type printing apparatus 5 according to a second embodiment of the present invention. That is, a printing apparatus that applies the third ink (ink containing a pigment) to a print medium and then ejects and reacts with the second ink (light C ink)
It is apparent that the present invention can be applied not only to the above-described full-line type device but also to a serial type device. The same elements as those shown in FIG. 5 are denoted by the same reference numerals, and the description thereof will not be repeated.

The recording paper 103 as a print medium is inserted from the paper supply unit 105 and discharged through the print unit 126. In the present embodiment, inexpensive plain paper that is generally widely used is used as the recording paper 103. In the printing unit 126, the carriage 107 is mounted on the print head 101B.
k, 101C ', 101C, 101M, and 101Y are mounted, and are configured to be able to reciprocate along the guide rail 109 by the driving force of a motor (not shown). The print head 101Bk discharges ink using a mixture of a dye and a pigment as a color material, as in the first embodiment. Also, the print heads 101C ', 101C, 10
1M and 101Y discharge light cyan (C ′) ink, cyan (C) ink, magenta (M) ink, and yellow (Y) ink, respectively. The ink is discharged onto the recording paper 103 in this order. Driven. Here, the color material density of the light cyan ink is 1%, which is about 1/3 of the color material density of the cyan ink, whereby the OD of the light cyan ink is set to about 0.57, and this is superimposed on the Bk ink. This can be made inconspicuous up to a maximum of about 100 m, which sometimes occurs.

Each head has a corresponding ink tank 108Bk, 108C ', 108C, 108M, 10
8Y, ink is supplied, and at the time of ink ejection, a drive signal is supplied to an electrothermal transducer (heater) provided for each ejection port of each head, thereby causing thermal energy to act on the ink to generate bubbles. The ink is ejected by utilizing the pressure at the time of foaming. Each head is provided with 64 ejection ports at a density of 360 dpi, and these are arranged in substantially the same direction as the transport direction Y of the recording paper 103, that is, in a direction substantially perpendicular to the scanning direction by each head. . The discharge amount of each discharge port is about 23 pl.

In the above configuration, the distance between the heads is 1
/ 2 inch, the print density in the scanning direction is 720 dpi, and the ejection frequency of each head is 7.2 kHz. Therefore, after the Bk ink of the head 101Bk is ejected, the light C ink of the head 101C 'is ejected. The time until this is completed is 0.025 sec.

FIGS. 9A to 9C schematically show another example of the head configuration in the serial printing apparatus as shown in FIG. 8, and are diagrams schematically showing the arrangement of the ejection ports.

As shown in FIG. 17A, the image forming apparatus has two ejection sections for ejecting black ink (ejection sections 101Bk1, 1B1).
01Bk2), a configuration in which a discharge unit 101C ′ that discharges the light C ink is disposed between them. In this case, the light C ink is applied after the black ink is applied. Further, a black ink may be further applied thereafter.

The head configuration shown in FIG. 9A and FIGS. 9B and 9C is an integrated head structure for some inks. FIG. 9 (b)
Similarly to the above, there is shown an example having two black ink discharge units, but these discharge units 101Bk1 and 101Bk2 are arranged so as to be able to discharge before the light C ink. According to this configuration, the light C ink is applied after two drops of the black ink are applied.

FIG. 9 (c) shows the structure of FIG.
The ink compositions of M and Y are different. Two ejection units for M ink and two ejection units for Y ink are provided (ejection unit 1).
01M1, 101M2, ejection units 101Y1 and 101Y
2), the ejection unit 101Bk of each ink perpendicular to the operation direction
2, 101M1, 101Y1 and the ejection units 101C, 10Y
1M2 and 101Y2. Here, 101C ′ and 101C, 101M1 and 101M2, 10
1Y1 and 101Y2 are for ejecting light ink and dark ink, respectively. Of course, in these integrated head units, the discharge ports and the liquid chambers communicating with the discharge ports for each ink are separated from each other. Therefore,
Each ejection unit is similar to each ink head.

FIGS. 10A and 10B are schematic views showing another example of the head unit used in the above-mentioned serial type device.

The example shown in FIG. 10 (a) is of a type in which Bk, C and M discharge sections are arranged in a vertical direction, and these discharge sections are formed integrally. Similarly, light C, light M, and Y discharge sections 101C ', 101M', and 101Y are arranged in the vertical direction, and these are also integrally formed.

Here, a unit is formed so that the ejection portions of the Bk ink and the light C ink are correspondingly parallel in order to be ejected to the same pixel for scanning. Thus, the light C ink can be ejected after being superimposed on the Bk ink.

In this example, the ejection section arrays Bk, C, and M and the ejection section arrays C, M, and Y may be integrated as a head.

If Bk, C, and M are dedicated ejection part arrays of anionic color materials, and light C, light M, and Y are dedicated ejection part rows of polyvalent metal salts, suction is simultaneously performed in each ejection part row. Even if a recovery operation such as wiping or the like is performed, the ink is mixed and these react and the insoluble matter does not block the ejection portion,
The configuration of the recovery system can be simplified.

In the example shown in FIG. 10B, a head unit in which three rows of ejection parts are integrally formed is arranged in two scanning directions. The head unit on the side where the ejection precedes by scanning is an ejection unit for Bk ink, light C ink, and light M ink, and the other head unit is Y ink, M ink.
Ink and C ink ejection sections are arranged.

In the above, the mode in which the Bk ink is applied and then the light C ink is applied thereto has been described. However, the light C ink is applied before the Bk ink, and the light C ink is applied to the light C ink. Bk ink may be applied. As the ink, those shown in Example 1 are preferably used. In this example, as the light M, M, and Y, for example, by using an ink having the following composition,
A higher quality color image can be formed.

[0175]

[Table 7]

[0176]

[Table 8]

[0177]

[Table 9] (Embodiment 3) Another embodiment of the present invention will be described below. In this embodiment, the content of acetylenol EH of the light C 'ink in the above-described embodiment is set to 2 parts by weight, and the permeability is further increased, thereby achieving higher speed fixing.

High-speed fixing is a main configuration for increasing the printing speed, that is, for improving the throughput.
The throughput can be directly improved by increasing the drive frequency of the print head and the transport speed of the print medium. However, if the ink and the like on the discharged print medium are not fixed after printing is completed, subsequent handling is inconvenient, and in a configuration in which the discharged print media are stacked, the unfixed print medium is not fixed. There is also a risk that other print media will be soiled by the ink.

That is, among the various factors contributing to the increase in the printing speed, those directly recalled are:
As described above, the speed at which the print medium on which printing has been completed is ejected, which depends on the transport speed of the print medium or the scanning speed of the print head. In other words, in an apparatus using a so-called full multi-type print head, the transport speed of the print medium in the printing operation means the paper discharge speed as it is, and in an apparatus using a serial type print head, scanning is performed. The speed will consequently be linked to the paper ejection speed of the printed print medium. The transport speed of the print medium and the like are correlated with the ink ejection cycle to the pixels via the print resolution, that is, the dot density. That is, in a configuration in which one pixel is printed using ink ejected from a plurality of print heads, when the resolution is fixed and considered, the ejection cycle for the pixel correlates with the transport speed and the like.

In this embodiment, by using a processing liquid having a high penetration rate, a relatively high-speed fixing is possible even when a mixed ink having a low penetration rate is used, especially for improving the OD value. .

Example 4 An experiment was conducted in the same manner as in Example 1 except that the light cyan ink was replaced with the following light blue ink and the black (B) ink was replaced with the following composition. Was performed.

[0182]

[Table 10]

[0183]

[Table 11] The Ka value of this black ink was 0.33 (ml · m ⁻²
Msec ^-1/2 ).

Example 5 An experiment was performed in the same manner as in Example 1 except that the light cyan ink was replaced with the light blue ink having the following composition, and the composition of the black ink was changed as follows. Was performed.

[0185]

[Table 12]

[0186]

[Table 13] The Ka value of this black ink was 0.33 (ml · m
^-2 · msec ^-1/2 ).

The full-color images obtained in the above Examples 4 and 5 were particularly remarkable in comparison with Example 1 in terms of their granularity.

The light blue ink used two kinds of dyes. The magenta ink combined with the light blue ink was used as an ink containing the magenta dye of the structural formula (I) as a coloring material. If the cyan ink combined with the blue ink is an ink containing Acid Blue 9,
Probably due to the commonality of the color tone between the so-called dark and light inks, a further improvement in the graininess of the resulting image and a more favorable effect on the smoothness of the color tone of the image when a full-color image is formed are obtained. Can be

The full multi-type printing apparatus described above is used in a state where the print head is fixed in the printing operation, and the time required for transporting the recording paper is almost the time required for printing. It is a thing. Therefore, by applying the present invention to such a high-speed printing apparatus, the high-speed printing function can be further improved, and high-quality printing with a high OD value and no bleeding or haze can be realized.

Although the printing apparatus of this embodiment is most commonly used as a printer, it is needless to say that the printing apparatus is not limited to this and can be configured as a printing unit such as a copying apparatus or a facsimile.

The effect of the present embodiment is not limited to the configuration using one head for black ink as in the present embodiment, but two heads, and the ejection amount of each head is about 8 pl, for a total of about 16 pl. In this case, substantially the same effect can be obtained.

[0192]

According to the present invention, it is possible to provide an ink set for obtaining a higher quality color print. Further, according to the present invention, it is possible to provide a color ink jet printing method and apparatus capable of fixing ink at a high speed on a recording medium without deteriorating the quality of printed matter.

[Brief description of the drawings]

FIG. 1 is a conceptual diagram for presumably explaining the phenomenon of “exudation” of a reactant when an ink and a processing liquid are reacted.

FIG. 2 is a conceptual diagram for presumably explaining dot formation when an ink is applied to cause a reaction between the processing liquid and the ink after the processing liquid is applied to a print medium in one embodiment of the present invention.

FIG. 3A is a schematic diagram illustrating a state in which the ink according to the present invention is applied to the surface of a print medium. (B) is a schematic explanatory view of a state where a conventional pigment ink is applied to the surface of a print medium.

FIG. 4 is a diagram schematically showing an arrangement of print heads in the ink jet printer.

FIG. 5 is a side view illustrating a schematic configuration of a full line type printing apparatus.

6 is a block diagram showing a control configuration of the full-line type printing apparatus 1 shown in FIG.

FIG. 7 is a flowchart illustrating a process of generating ejection data of light cyan (C ′) ink.

FIG. 8 is a schematic perspective view showing a configuration of a serial type printing apparatus 5;

FIG. 9 is a schematic diagram illustrating a head configuration of a printing apparatus according to another embodiment of the present invention.

FIG. 10 is a schematic diagram showing a head configuration of a printing apparatus according to still another embodiment of the present invention.

[Explanation of symbols]

P Print medium S Treatment liquid Ip Pigment ink SP Penetrating tip Di Distance between pigment ink head and treatment liquid head 1 Printing device 5 Printing device 6 Treatment liquid 7 Haze 8 Pigment ink 9 Reactant 101g Head group 101 ( Bk1, Bk2, S, C, M, Y) Print head (ejection unit) 103 Recording paper 104 Platen 105 Feed unit 107 Carriage 108 (Bk, Bk1, Bk2, S, C, M, Y)
Ink tank 109 Guide rail 111 Transport belt 112, 113 Roller 114 Registration roller 115 Guide plate 116 Stocker 126 Print unit 201 System controller 202 Driver 204 Motor 206 Host computer 207 Receive buffer 208 Frame memory 209S, 209P Buffer 210 Print control unit 211 Driver 222 Abnormal sensor

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Jin Tsuboi 3-30-2 Shimomaruko, Ota-ku, Tokyo F-term in Canon Inc. (reference) 2C056 FC01 2H086 BA04 BA53 BA55 BA56 BA59 BA60 4J039 BE02 BE22 CA03 CA06 GA24

Claims (46)

[Claims] 1. An ink set comprising a first ink, a second ink, and a third ink, each containing an aqueous medium and a coloring material, wherein the first ink comprises an anionic dye as the coloring material. Wherein the second ink contains an anionic dye as the coloring material and has a lower coloring material concentration than the first ink, and the third ink comprises a first pigment and a second pigment. And a polymer dispersant for dispersing the second pigment, wherein the first pigment and the second pigment are both dispersed in the third state.
Wherein the first pigment is a self-dispersible pigment in which at least one anionic group is bonded to the surface of the first pigment directly or via another atomic group; The second pigment is a pigment that can be dispersed in the aqueous medium by a polymer dispersant, and the polymer dispersant is at least one of an anionic polymer dispersant and a nonionic polymer dispersant. And the second ink disperses at least one of the first pigment and the second pigment in the third ink when in contact with the third ink in a liquid state on a print medium. An ink set, further comprising a substance that destabilizes stability. 2. The ink set according to claim 1, wherein the substance that destabilizes the dispersion stability of at least one of the first pigment and the second pigment is a polyvalent metal ion or a salt thereof. 3. The method according to claim 1, wherein the anionic group is -COOM,-
The ink set according to claim 1, wherein the ink set is at least one selected from SO ₃ M, —PO ₃ HM, and —PO ₃ M ₂ (where M is each independently a hydrogen atom, an alkali metal, , Ammonium, or organic ammonium). 4. The other atomic group is selected from an alkylene group having 1 to 12 carbon atoms, a phenylene group which may have a substituent and a naphthylene group which may have a substituent. 3. The ink set according to any one of 3. 5. The ink set according to claim 1, wherein 80% or more of the particles of the first pigment have a particle size of 0.05 to 0.3 μm. 6. The ink set according to claim 5, wherein 80% or more of the particles of the first pigment have a particle size of 0.1 to 0.25 μm. 7. The ink set according to claim 1, wherein the second pigment is dispersed by adsorbing a polymer dispersant on a surface of the second pigment. 8. The ink set according to claim 1, wherein the polymer dispersant is at least one of a sulfonic acid-based polymer dispersant and a carboxylic acid-based polymer dispersant. 9. The ink set according to claim 1, wherein the second pigment includes at least two kinds of pigments having different structures. 10. The ink set according to claim 1, wherein the third ink is a black ink. 11. The ink according to claim 1, wherein the mass ratio of the first pigment to the second pigment in the third ink is in the range of 5/95 to 97/3. set. 12. The ink set according to claim 11, wherein the mass ratio of the first pigment to the second pigment in the third ink is in a range from 10/90 to 95/5. 13. The ink set according to claim 12, wherein the mass ratio of the first pigment to the second pigment in the third ink is in a range from 4/6 to 9/1. 14. The ink set according to claim 1, wherein the third pigment contains more of the first pigment than the second pigment. 15. The ink set according to claim 1, wherein at least one of the first pigment and the second pigment is carbon black. 16. The ink set according to claim 1, wherein the third ink further contains a dye. 17. The ink set according to claim 16, wherein the dye is an anionic dye. 18. The ink set according to claim 17, wherein the anionic dye is at least one selected from an acid dye, a direct dye and a reactive dye. 19. The ink set according to claim 18, wherein the anionic dye has a disazo skeleton or a trisazo skeleton. 20. The ink set according to claim 1, wherein the inks are used for inkjet recording. 21. (1) a first step of attaching a first ink containing an aqueous medium and an anionic dye as a colorant onto a print medium using an ink jet method; (2) an aqueous medium and a colorant Containing an anionic dye,
And a second step of depositing a second ink having a lower colorant concentration on the print medium by an ink jet method as compared with the first ink; and (3) adding the first pigment to an aqueous medium. A second pigment, and a polymer dispersant for dispersing the second pigment,
The first pigment and the second pigment are both contained in a dispersed state, and the first pigment has at least one anionic group bonded to the surface of the first pigment directly or via another atomic group. Wherein the second pigment is a pigment which can be dispersed in the aqueous medium by a polymer dispersant, and wherein the polymer dispersant is an anionic polymer dispersant and a nonionic. A third step of depositing a third ink, which is at least one of a hydrophilic polymer dispersant, on a print medium using an inkjet method, wherein the second ink comprises the third ink and a print medium. Further comprising a substance that destabilizes the dispersion stability of at least one of the first pigment and the second pigment in the third ink when contacted in a liquid state above, and Following the third step, Alternatively, the ink-jet printing method is performed so that the second ink and the third ink are in liquid contact with each other substantially simultaneously on the print medium. 22. (1) A first step of attaching a first ink containing an aqueous medium and an anionic dye as a colorant onto a print medium by using an ink jet method, and (2) as an aqueous medium and a colorant. The anionic dye, and the first
A second step of depositing a second ink having a lower colorant concentration on a print medium using an ink jet method as compared with the ink of (1); and (3) disposing a first pigment and a second pigment in an aqueous medium.
And a polymer dispersant for dispersing the second pigment, wherein the first pigment and the second pigment are both contained in a dispersed state, and wherein the first pigment has at least one anion. A self-dispersible pigment in which a hydrophilic group is bonded to the surface of the first pigment directly or via another atomic group, wherein the second pigment is dispersed in the aqueous medium by a polymer dispersant. A third ink in which the polymer dispersant is at least one of an anionic polymer dispersant and a nonionic polymer dispersant, and the third ink is deposited on a print medium by an inkjet method. Wherein the second ink comprises, when in contact with the third ink in a liquid state on a print medium, the second ink having the first pigment and the second pigment in the third ink. Destabilize at least one dispersion stability The method further comprises a substance, and the third step is performed, following the second step, such that the second ink and the third ink come into contact with each other in a liquid state on the print medium. Inkjet printing method. 23. The substance which destabilizes the dispersion stability of at least one of the first pigment and the second pigment in the third ink is a polyvalent metal ion or a salt thereof. 3. The ink-jet printing method according to 1. 24. The inkjet printing method according to claim 21, wherein the third ink is a black ink. 25. The area according to claim 24, wherein the area where the second ink and the third ink are in contact in a liquid state is a boundary area between a black image and a color image formed by the third ink. Inkjet printing method. 26. The permeation rate of at least one of the first ink and the second ink is Ka by Bristow's method.
The inkjet printing method according to any one of claims 21 to 25, wherein the value is 5.0 ml · m ^-2 · msec ^-2/1 or more. 27. The ink-jet printing method according to claim 21, wherein the permeation speed of the third ink is less than 1 ml · m ⁻² · msec ^{−1/2 as} a Ka value by the Bristow method. 28. The method according to claim 28, wherein the anionic group is —COOM;
-SO ₃ M, -PO ₃ HM and -PO ₃ inkjet printing method according to any one of claims 21 to 27 is at least one of which is selected from among M ₂ (where, M are each independently a hydrogen Atoms, alkali metals, ammonium,
Or represents an organic ammonium). 29. The other atomic group is selected from an alkylene group having 1 to 12 carbon atoms, a phenylene group which may have a substituent and a naphthylene group which may have a substituent. 29. The inkjet printing method according to any one of items 28. 30. The ink-jet printing method according to claim 21, wherein 80% or more of the particles of the first pigment have a particle size of 0.05 to 0.3 μm. 31. The ink-jet printing method according to claim 30, wherein 80% or more of the particles of the first pigment have a particle size of 0.1 to 0.25 μm. 32. The method according to claim 21, wherein the second pigment is dispersed by adsorbing a polymer dispersant on the surface thereof.
31. The ink-jet printing method according to any one of 31. 33. The inkjet printing method according to claim 21, wherein the polymer dispersant is at least one of a sulfonic acid-based polymer dispersant and a carboxylic acid-based polymer dispersant. 34. The ink jet printing method according to claim 21, wherein the second pigment contains at least two kinds of pigments having different structures. 35. The inkjet according to claim 21, wherein the mass ratio of the first pigment to the second pigment in the third ink is in the range of 5/95 to 97/3. Printing method. 36. The inkjet printing method according to claim 35, wherein the mass ratio of the first pigment to the second pigment in the third ink is in a range of 10/90 to 95/5. 37. The ink-jet printing method according to claim 36, wherein a mass ratio of the first pigment to the second pigment in the third ink is in a range of 4/6 to 9/1. 38. The ink-jet printing method according to claim 21, wherein the third ink contains more of the first pigment than the second pigment. 39. The inkjet printing method according to claim 21, wherein at least one of the first pigment and the second pigment is carbon black. 40. The inkjet printing method according to claim 21, wherein the third ink further contains a dye. 41. The ink jet printing method according to claim 40, wherein the dye is an anionic dye. 42. The ink jet printing method according to claim 41, wherein the anionic dye is at least one selected from an acid dye, a direct dye and a reactive dye. 43. The ink-jet printing method according to claim 42, wherein the anionic dye has a disazo skeleton or a trisazo skeleton. 44. A recording unit, comprising: an ink storage section for storing each ink constituting the ink set according to claim 20, and a head section for discharging the ink. 45. An ink cartridge, comprising: an ink storage section that stores each ink constituting the ink set according to claim 1. Description: 46. An ink set comprising the ink set according to claim 20, and a recording head for individually discharging these inks by an ink jet printing method. Characteristic inkjet printing device.