JP7104895B2 - Image forming method and printed matter - Google Patents

Description

The present invention relates to an image forming method, printed matter, and an image forming apparatus.

The inkjet recording method is an on-demand method that does not require a printing plate like offset printing, and is known as an excellent recording method that is relatively insensitive to recording media. It is a printing method in which characters, images, etc. are printed by attaching to a recording medium. This system does not require complicated equipment, and is compact, high-speed, low-noise, easy to colorize, low running cost, and highly flexible in recording patterns. Widely used.

When the recording medium is plain paper having high ink absorbency, there are problems such as bleeding (feathering) of the printed image and low optical density (OD). If the OD is low, the density cannot be obtained efficiently, a large amount of ink is consumed, and the running cost is high.

On the other hand, for coated paper such as coated paper and glossy paper, by making it easier for the colorant to stay in the vicinity of the surface, it is aimed at suppressing feathering, which is the above problem, and achieving a high OD. In order to suppress feathering and obtain a high OD, it is important to suppress the spread of the ink in the horizontal direction on the surface of the coated paper immediately after landing and the penetration into the coated paper. However, if the coloring agent is allowed to remain excessively near the surface, peeling off (scratch resistance) by rubbing with a finger, clothes, an eraser, a marking pen, or the like becomes a problem. In recent years, in particular, the demand for large-area inkjet images has increased, and images are often rolled up for transportation. Ink jet images are often required to form a color image with a large image area, so even if the peeling is slight, the image quality is greatly reduced.

Bleeding of an ink image is caused by using a recording paper coated with a so-called processing agent that prevents ink bleeding (see, for example, Patent Documents 1 and 2), or by using a recording paper coated with a processing liquid that prevents ink bleeding. It can be suppressed by applying to the surface and forming an image by inkjet (see Patent Document 3). However, abrasion resistance and bleeding are contrary to each other, and when an attempt is made to completely suppress bleeding, the abrasion resistance often deteriorates.

When no processing agent is used, most of the liquid component (solvent) of the ink quickly permeates the paper, and at that time, part of the coloring material (dye or pigment) also migrates to the paper, resulting in bleeding. . However, since the solvent component is reduced and the solid content becomes substantially uniform, the image itself is uniform, has high mechanical strength, and is excellent in abrasion resistance. On the other hand, when ink is placed on paper with a large amount of processing agent on the surface, the ink does not permeate the paper, but the composition of the ink image is different on the paper side and the surface, so the image is rubbed. In many cases, the surface of the image was peeled off. In particular, quinacridones, which are magenta pigments, are prone to excessive growth of particles during the process of pigmentation, and therefore images formed with magenta ink often have poor scratch resistance.

The distribution of components in the ink-jet image is important for abrasion resistance, and particularly when the colorant is a pigment, the distribution of the pigment is very important.
In the analysis of inkjet images, for example, the oldest simple analysis method is a method of observing a cross section of a printed sample with a general optical microscope. However, this analysis method is limited to macroscopic observation of a cross section due to its low spatial resolution, and does not lead to observation of the shape of an image layer with a spatial resolution worthy of evaluation. Furthermore, the information obtained is limited to two-dimensional information, not three-dimensional information.

For example, as analysis methods for obtaining information on the depth direction and the periphery of a printed sample, there are a secondary ion mass spectrometer (SIMS), an Auger electron spectrometer (AES), an X-ray photoelectron spectroscopy (XPS), and the like. In these analysis methods, beams such as ions, electrons, and X-rays are used to measure the printed sample while sputtering it, thereby obtaining information on the depth direction and the periphery of the printed sample. However, these analysis methods have very poor measurement efficiency because the depth information of the printed sample is affected by the sputtering speed. Furthermore, since the printed sample must be sputtered in a high vacuum, preparations such as processing the printed sample and evacuation require a lot of time and effort, and the sputtering time also requires a huge amount of time.

Further, for example, Patent Document 4 proposes a method using a focused ion beam apparatus (FIB) to obtain information by preparing a highly accurate cross section of a printed sample. A scanning electron microscope (SEM) and an optical microscope were used to image the cross section of the printed sample, and a wavelength dispersive X-ray spectrometer (EPMA) was used to obtain the amount of carbon element, allowing us to determine the distribution of the ink permeating the paper. to parse

Further, in Patent Documents 5 and 6, a tapered shape is cut at a predetermined angle with a cutting edge from the surface of a printed sample toward the inside, and Fourier transform infrared spectroscopy (FTIR) or infrared attenuated total reflection spectroscopy (ATR) is performed. proposed a method of obtaining information in the Z-axis direction, the X-axis direction and the Y-axis direction on a cut surface and a cut piece.

However, conventional analysis methods require a lot of time and effort, and the information obtained is two-dimensional information or pseudo three-dimensional information, and the three-dimensional shape of the actual image layer cannot be obtained. .
Thus, the analysis of ink-jet images is very difficult, and it was not known at all what kind of image forming method would provide excellent scratch resistance.
An object of the present invention is to provide an image forming method which is excellent in abrasion resistance.

Ｆ’（Ｘｉ，Ｙｊ）≦０．７５×Ｆ’ave
となるＦ’（Ｘｉ，Ｙｊ）が、全Ｆ’（Ｘｉ，Ｙｊ）の０．０５～９．００％である画像を形成する画像形成方法。 The image forming method of the present invention is as follows.
(1) An image forming method for forming an image on a printed material using an ink containing a fluorescent substance,
Fluorescence intensity F (Xi, Yj, Zk) obtained by measuring the image with a confocal fluorescence microscope
(However, i = 1 to n1, j = 1 to n2, k = 1 to n3, k = 1 represents the position of the bottom surface of the image in the Z direction, and k = n3 represents the position of the top surface of the image in the Z direction.)
In F'(Xi, Yj) and F'ave obtained by the following formula from

F'(Xi, Yj) ≤ 0.75 x F'ave
An image forming method for forming an image in which F'(Xi, Yj) is 0.05 to 9.00% of the total F'(Xi, Yj).

The present invention can provide an image forming method with excellent scratch resistance.

(a) is a schematic diagram of the configuration of a general full-field fluorescence microscope, and (b) is a schematic diagram of the configuration of a confocal fluorescence microscope. 1 is a perspective explanatory view showing an example of a recording apparatus of the present invention; FIG. It is a perspective explanatory view of a main tank. FIG. 10 is a diagram showing the result of superimposing (averaging fluorescence intensity) the Z-direction data of each F(X, Y) measured by a confocal fluorescence microscope in the image obtained in Example 1; FIG. 5 is a diagram of extracting a portion where the average value (F'ave) of fluorescence intensity is 75% or less from FIG. 4 .

Considering that the distribution of colorant is important for the scratch resistance of an image, we investigated various analysis methods and found that if the colorant of the image is a fluorescent substance, the distribution of the colorant can be measured using a confocal fluorescence microscope. was obtained three-dimensionally, and when various images were analyzed and the relationship with scratch resistance was investigated, a surprising fact was discovered.

A three-dimensional fluorescence image of a magenta image obtained with a confocal fluorescence microscope shows the distribution of the magenta pigment. It was found that unevenness is better. When the unevenness was examined in detail, it was found that the magenta pigment was almost uniformly present in the ink layer, but there were fine cracks (depletion formed in the image) etc. in the ink layer itself. It was found that slight unevenness occurred in the distribution of the pigment. Usually, when such cracks occur, the mechanical strength of the ink layer is lowered, so that the abrasion resistance is significantly lowered. Certainly, the larger the cracks, the lower the scratch resistance. However, it was found that the presence of fine cracks to some extent significantly improves the abrasion resistance. It was found that these fine cracks are very minute and exist on the surface of the ink layer, but may also exist in the ink layer.

The present inventors analyzed how these fine cracks are generated, and in order to suppress ink bleeding, analyzed image formation on paper (printing material) coated with a processing agent. Adhered ink is agglomerated by the treatment agent and loses its fluidity. However, the ink of an image that causes fine cracks in the ink layer agglomerates almost at the same time as it adheres to the paper, and the solid content is fixed as it is. I found out. It was also found that the ink layer shrinks during the drying process in which the solvent in the ink evaporates, and fine cracks occur in the portions that cannot withstand the shrinkage. It was found that although fine cracks occur, the mechanical strength of the surface of the ink layer is maintained because the composition of the solid content in the ink layer is constant. On the other hand, for images without fine cracks in the ink layer, the ink adheres to the paper, and the processing agent dissolves in the ink solvent, causing partial coalescence (usually the bottom surface), and the entire ink layer gradually coalesces. Therefore, it was found that although leveling does not cause cracking of the ink image, the composition of the solid content in the vicinity of the surface of the ink image is different, and the abrasion resistance is lowered.

The thicker the ink layer, the more fine cracks in the ink layer, and the thinner the ink layer, the fewer fine cracks in the ink layer. The thickness of a general ink layer is 1.3 to 2.5 μm, and fine cracks always occur in an ink layer with particularly excellent scratch resistance.

Next, the present inventors studied what kind of condition the fine cracks in the ink layer should be in to form an ink image with excellent scratch resistance. It was found that there were many cracks leading to

Ｆ’（Ｘｉ，Ｙｊ）≦０．７５×Ｆ’ave
となるＦ’（Ｘｉ，Ｙｊ）が、全Ｆ’（Ｘｉ，Ｙｊ）の０．０５～９．００％である画像を形成する画像形成方法である。 The present inventors found that fine cracks in the ink image are mainly cracks extending from the surface of the ink image to the bottom surface of the ink image. The present inventors have found that fine cracks in an ink image can be detected as a portion with low fluorescence intensity, and found that an ink image with excellent abrasion resistance can be obtained by specifying the area ratio of the portion with low fluorescence intensity, leading to the present invention. . That is, the present invention
(1) An image forming method for forming an image on a printed material using an ink containing a fluorescent substance,
Fluorescence intensity F (Xi, Yj, Zk) obtained by measuring the image with a confocal fluorescence microscope
(However, i = 1 to n1, j = 1 to n2, k = 1 to n3, k = 1 represents the position of the bottom surface of the image in the Z direction, and k = n3 represents the position of the top surface of the image in the Z direction.)
In F'(Xi, Yj) and F'ave obtained by the following formula from

F'(Xi, Yj) ≤ 0.75 x F'ave
This is an image forming method for forming an image in which F'(Xi, Yj) is 0.05 to 9.00% of the total F'(Xi, Yj).

Ｆ’（Ｘｉ，Ｙｊ）≦０．７５×Ｆ’ave
となるＦ’（Ｘｉ，Ｙｊ）が、全Ｆ’（Ｘｉ，Ｙｊ）の０．０５～９．００％である印刷物。
（７）インク、インクを吐出する吐出手段を有する画像形成装置であって、
該インクは、蛍光物質を含有するインクであり、
画像を共焦点蛍光顕微鏡により測定した蛍光強度Ｆ（Ｘｉ，Ｙｊ，Ｚｋ）
（但しｉ＝１～ｎ１、ｊ＝１～ｎ２、ｋ＝１～ｎ３、ｋ＝１は画像底面のＺ方向の位置、ｋ＝ｎ３は画像上面のＺ方向の位置を表す。）
から下記式により求められるＦ’（Ｘｉ，Ｙｊ）、Ｆ’aveにおいて、

Ｆ’（Ｘｉ，Ｙｊ）≦０．７５×Ｆ’ave
となるＦ’（Ｘｉ，Ｙｊ）が、全Ｆ’（Ｘｉ，Ｙｊ）の０．０５～９．００％である画像を形成する画像形成装置。 The present invention relates to the image forming method of (1) above, but also includes the following (2) to (7) as embodiments.
(2) The image forming method according to (1), wherein the fluorescent substance is a magenta pigment or a yellow pigment.
(3) The image forming method according to (1) or (2) above, wherein coated paper is used as the material to be printed.
(4) The image forming method according to any one of (1) to (3) above, which comprises a step of applying a pretreatment liquid in which a processing agent is dissolved to the material to be printed.
(5) The image forming method according to any one of (1) to (4) above, wherein the image forming method is a method of forming an image by ejecting the ink.
(6) A printed matter having an image on a substrate,
Fluorescence intensity F (Xi, Yj, Zk) obtained by measuring the image with a confocal fluorescence microscope
(However, i = 1 to n1, j = 1 to n2, k = 1 to n3, k = 1 represents the position of the bottom surface of the image in the Z direction, and k = n3 represents the position of the top surface of the image in the Z direction.)
In F'(Xi, Yj) and F'ave obtained by the following formula from

F'(Xi, Yj) ≤ 0.75 x F'ave
F'(Xi, Yj) is 0.05 to 9.00% of the total F'(Xi, Yj).
(7) An image forming apparatus having ink and ejection means for ejecting ink,
The ink is an ink containing a fluorescent substance,
Fluorescence intensity F (Xi, Yj, Zk) measured by a confocal fluorescence microscope
(However, i = 1 to n1, j = 1 to n2, k = 1 to n3, k = 1 represents the position of the bottom surface of the image in the Z direction, and k = n3 represents the position of the top surface of the image in the Z direction.)
In F'(Xi, Yj) and F'ave obtained by the following formula from

F'(Xi, Yj) ≤ 0.75 x F'ave
An image forming apparatus for forming an image in which F'(Xi, Yj) is 0.05 to 9.00% of the total F'(Xi, Yj).

FIG. 1(a) is a schematic diagram of the configuration of a general full-field fluorescence microscope. Light emitted from a lamp 1 as a light source is reflected by a dichroic mirror 4 via an illumination lens 2 , passes through an objective lens 3 , and enters a sample 9 . Fluorescence excited by the incident light and reflected light pass through the objective lens 3, and only the fluorescence passes through the dichroic mirror 4. FIG. Detector 8 detects this passing fluorescence. Fluorescence that is not focused on the focal plane 7 is mixed and detected at the imaging position of the detector 8 .

On the other hand, FIG. 1(b) is a schematic diagram of the configuration of a confocal fluorescence microscope. It is designed so that only the fluorescent light focused on the focal plane 7 among the fluorescent light irradiated and excited from the point light source 5 reaches the imaging plane of the detector 8 . By continuously acquiring this in the Z-axis direction and superimposing the images, a three-dimensional shape can be constructed without contact.

The confocal fluorescence microscope used in the image forming method of the present invention can be a conventionally known confocal fluorescence microscope having a pinhole at the imaging position of the fluorescent image.
The confocal fluorescence microscope preferably has a configuration with high spatial resolution in order to acquire the three-dimensional shape of the image layer with higher definition. Laser light with high coherence is preferable for the light source. The objective lens is preferably an immersion lens with a high numerical aperture (NA), more preferably an oil immersion lens with a higher NA. As for the oil used for the objective lens, it is common to use the oil for exclusive use by the manufacturer of the confocal fluorescence microscope, but it is preferable that the refractive index of the liquid that is directly immersed in the coated paper is closer to that of the coated paper.

The inventors selected salad oil, which has a refractive index closer to that of the image, as the liquid for directly immersing the coated paper. On the other hand, the manufacturer's exclusive oil was used as the liquid in which the objective lens was immersed, and observations were made by sandwiching a cover glass between the manufacturer's exclusive oil and salad oil.
By using salad oil, since the refractive index of salad oil is close to the refractive index of the image, optical unevenness is eliminated and the resolution is increased. If salad oil is not used, the refractive index difference between the air and the image is large, so if the image has unevenness, refraction occurs at the air/image interface, resulting in poor resolution.

The present inventors used an inverted TCS SP8 (manufactured by Leica) as a confocal fluorescence microscope. A laser beam was used as a light source, and a PTM or HyD detector was used as a detector. Also, an acousto-optic polarization element AOBS was used instead of the dichroic mirror. An oil immersion lens HC PLAPO CS2 with NA 1.4 was used as an objective lens.

Although there is no particular restriction on the observation field diameter, the XY plane preferably has a diameter of 100 to 2500 μm ² in order to evaluate the relationship between high image quality (blur suppression), high color development (high OD), and abrasion resistance. When the area is wider than 2500 μm ² , high image quality (bleeding suppression), high color development (high OD), and large distortion of the entire image unrelated to abrasion resistance are likely to be reflected, resulting in high image quality (blurring suppression) and high color development (high OD). ), it becomes difficult to calculate the roughness of the bottom surface of the image layer, which is related to the scratch resistance. In addition, since the field of view is too narrow at 100 μm ² or less, it is limited to local information. becomes difficult to calculate.

In the confocal fluorescence microscope, while changing the position in the Z direction, the fluorescence intensity at each point on the XY plane is measured at that position in the Z direction. The measurement range in the Z direction must cover the bottom and top of the ink image. When the interface between the bottom surface and the surface of the ink image is unclear, the measurement should be performed in a range sufficiently lower than the bottom surface of the ink image and sufficiently higher than the surface of the ink image. Areas with no ink image have no fluorescence intensity, and therefore do not interfere with the calculation of the percentage of defective areas in the ink image.

Considering that the thickness of the ink image is 1 to 3 μm, the finer the resolution in the Z direction, the better. In view of the performance of the fluorescence microscope, the present inventors found that the smaller the measurement position interval Zstep in the Z direction, the better, but that good measurement results can be obtained if Zstep=0.1545 μm. .

前記（Ｘｉ，Ｙｊ，Ｚｋ）は、画像の３Ｄでの座標を表す。Ｚは、Ｚ軸方向（深さ方向）、であり、Ｘ、Ｙは、Ｘ、Ｙ軸方向（縦横方向）を表す。即ち、蛍光強度Ｆ（Ｘｉ，Ｙｊ，Ｚｋ）は、座標（Ｘｉ，Ｙｊ，Ｚｋ）での蛍光強度であり、Ｆ’（Ｘｉ，Ｙｊ）は、Ｘ，Ｙ方向の位置が（Ｘｉ，Ｙｊ）での、蛍光強度のＺ方向の平均である。測定は、どの方向も等間隔で測定した。
例えば、Ｘ，Ｙ方向は１８．４５μｍ×１８．４５μｍの領域を、５１２×５１２に分割して測定する場合、ｎ１＝５１２，ｎ２＝５１２となる。
Ｚ方向は、０．１５４５μｍ間隔で測定した。Ｚ方向は、画像底面の被印刷物に凹凸がある、画像表面及び底面に凹凸がある、画像を完全に水平に固定することが難しい、こと等を考慮し、ｋ＝１の位置及び、ｎ３は余裕をもって画像の膜厚よりも大きな範囲で、画像の膜厚が十分に含まれる範囲で測定することが好ましい。ｋ＝１の位置は、基本的には測定領域内での画像底面の最も低い位置を設定するが、測定領域内の画像が全て入るよう、ｋ＝１の位置が画像底面の最も低い位置よりも低くなってもかまわない。また、ｎ３も同様に、余裕をもって画像の膜厚よりも大きな範囲で、画像の膜厚が十分に含まれる範囲で測定することが好ましい。本発明の実施例ではｎ３＝８６で測定した。Ｆ’（Ｘｉ，Ｙｊ）の値は、ｋ＝１の位置及びｎ３をどこまでとるかによって変わり、ｋ＝１の位置が画像底面の位置から離れるほど、及びｎ３が大きくなるほど、Ｆ’（Ｘｉ，Ｙｊ）の値は小さくなっていく。ただ、全ての箇所のＦ’（Ｘｉ，Ｙｊ）の値も小さくなるため、平均値のＦ’aveも同じように小さくなり、（Ｆ’（Ｘｉ，Ｙｊ）≦０．７５×Ｆ’aveの算出には影響を与えない。 A method of defining an image in the image forming method of the present invention will be described.
Fluorescence intensity F (Xi, Yj, Zk) measured by a confocal fluorescence microscope
(However, i = 1 to n1, j = 1 to n2, k = 1 to n3, k = 1 represents the position of the bottom surface of the image in the Z direction, and k = n3 represents the position of the top surface of the image in the Z direction.)
, the fluorescence intensity in the Z direction is averaged to create a two-dimensional fluorescence intensity F'(Xi, Yj), and the average value F'ave of F'(Xi, Yj) is calculated.

The (Xi, Yj, Zk) represent the 3D coordinates of the image. Z is the Z-axis direction (depth direction), and X and Y are the X- and Y-axis directions (vertical and horizontal directions). That is, the fluorescence intensity F(Xi, Yj, Zk) is the fluorescence intensity at the coordinates (Xi, Yj, Zk), and F'(Xi, Yj) is the position at (Xi, Yj) in the X and Y directions. is the Z-direction average of the fluorescence intensity at . Measurements were taken at regular intervals in all directions.
For example, when measuring a region of 18.45 μm×18.45 μm in the X and Y directions by dividing it into 512×512, n1=512 and n2=512.
The Z direction was measured at intervals of 0.1545 μm. In the Z direction, the position of k = 1 and n3 are determined by taking into consideration the fact that the printed material on the bottom surface of the image has unevenness, the surface and bottom of the image have unevenness, and it is difficult to fix the image completely horizontally. It is preferable to measure within a range that is larger than the film thickness of the image with a margin and within a range that sufficiently includes the film thickness of the image. The position of k = 1 basically sets the lowest position of the bottom of the image within the measurement area, but the position of k = 1 is lower than the lowest position of the bottom of the image so that the entire image within the measurement area can be included. It doesn't matter if it's too low. Similarly, it is preferable to measure n3 in a range that is larger than the film thickness of the image with a margin and that the film thickness of the image is sufficiently included. In the example of the present invention, it was measured at n3=86. The value of F'(Xi, Yj) changes depending on the position of k=1 and how far n3 is taken. Yj) is getting smaller. However, since the values of F'(Xi, Yj) at all points also become smaller, the average F'ave also becomes smaller, and (F'(Xi, Yj) ≤ 0.75 x F'ave It does not affect calculations.

If the two-dimensional fluorescence intensity F'(Xi, Yj) is 75% or less of F'ave, the image is 0.05 to 9.00% of the total F'(Xi, Yj). If so, the scratch resistance will be very excellent.
The two-dimensional fluorescence intensity F' (Xi, Yj) is 75% or less of F'ave (F' (Xi, Yj) ≤ 0.75 × F'ave) is a fine crack portion of the image. Become. If a fine crack exists straight in the Z direction, F'(Xi, Yj) of the fine crack is 0% of F'ave, but the fine crack must be curved. There are many, and sometimes they exist only inside. Also, if the coefficient applied to F'ave is too large, the unevenness of the bottom or surface of the image will be flattened. If F'ave is 75% or less, all fine cracks can be accurately detected.

In the present invention, the ratio of F'(Xi, Yj)≦0.75×F'ave is 0.05 to 9.00%, preferably 0.07 to 7.00%, more preferably 0.07 to 7.00%. 10 to 6.00%. If the ratio of locations where F'(Xi, Yj)≤0.75×F'ave is less than 0.05%, the abrasion resistance is remarkably lowered. If the ratio of the locations where F'(Xi, Yj)≤0.75×F'ave is greater than 9.00%, color unevenness in the image occurs due to the presence of defective portions, and the image quality deteriorates. The mechanical strength of the image is lowered, and the abrasion resistance is lowered.
Normally, if the thickness of the ink layer is constant and there are no fine cracks, F'(Xi, Yj) will be the same value even if the pigment has a deviation between the bottom surface and the surface of the image, so F'(Xi , Yj).ltoreq.0.75.times.F'ave.

In order for the two-dimensional fluorescence intensity F' (Xi, Yj) to be 75% or less of F'ave to be 0.05 to 9.00% of the total F' (Xi, Yj), the pigment It is thought that the reactivity between the pigment and the processing agent and the manner in which the pigment and the processing agent are mixed have an effect. The reactivity between pigments and processing agents depends on the individual materials, but how they are mixed also has a great effect. If the processing agent is held on paper, it cannot come into contact with the pigment of the ink unless it is dissolved in the ink solvent. It mixes very quickly and can instantly coalesce the ink. Therefore, it is preferable to use a treating agent and to contact the ink without drying the treating agent.

<Coated paper>
The image forming method of the present invention can also be used for images on plain paper. However, since the surface of plain paper has no flat portion and the ink permeates deeply, it is difficult to specify the bottom surface of the image. Therefore, the image forming method of the present invention is extremely effective for images on coated paper.
Coated paper is paper whose surface has been coated with paint to increase its whiteness and smoothness. Coated paper includes lightly coated paper, art paper, coated paper, cast coated paper and the like. Paints are made by mixing white pigments (talc, pyrophyllite, clay (kaolin), titanium oxide, magnesium carbonate, calcium carbonate, etc.) with an adhesive such as starch or latex.

Slightly coated paper is paper with a coating weight of 12 g/m ² or less, and is made by thinly coating both sides of uncoated high-quality or medium-quality paper with a roll coater. It is often used in magazines, flyers, etc. Art paper is paper with a coating weight of about 40 g/m ² and is used for photo printing where finishing is important. Coated paper is paper with a coating weight of about 20 g/m ² to 15 g/m ² , and coated paper is used for color pages of magazines and pamphlets. Cast-coated paper is paper that is dried by pressing art paper or coated paper against a metal surface before the paint dries. It has a very high gloss and is often used for calendars and magazine covers.

A commercially available coated paper may be used as it is, or a treatment liquid containing a treating agent may be applied to the coated paper and dried before use.
As the treatment agent, an inorganic oxide dispersion system treatment agent is described. The function of the inorganic oxide dispersing agent mainly contributes to the prevention of strike-through and the sharpness of the image. In the case of a cationic coloring agent, it also contributes to improving the water resistance of anionic coloring agents. In addition, particles having a certain large particle size prevent the surface image from being seen through. As the material, cationic or anionic metal oxides such as titanium oxide, silicon oxide and zirconium oxide can be used. Commercially available alumina and silica colloidal sols can also be used.

A wetting agent may be added to these to prevent evaporation and drying. Also, it can be used without any particular addition. Also, various other additives (penetrants, surfactants, antiseptic mold agents, etc.) can be used as described for the colored inks. These may be used by mixing with various dispersants and water-soluble resins.

The content of the metal oxide in the treatment liquid is preferably 0.5 to 30% by mass. If the amount is too small, there is no effect, and if the amount is too large, the jetting stability is poor.

The pH of the treatment liquid is adjusted to 3-10. Cationic colloids are used relatively acidic and anionic colloids relatively basic.

When the processing liquid containing these inorganic oxides is in contact with the recording liquid, it contributes to the sharpness and fixability of images.

A processing agent having a cationic group is mainly used for fixing dyes and pigments. This function is exhibited only when the applied treatment liquid comes into contact with the colored ink on the recording surface side. The compound having a cationic group may be in a state of forming a salt with a counter anion such as chloride ion in a solution, or may be in a so-called free state without a counter anion.

（上記式中、Ｒ₁，Ｒ₂，Ｒ₃は水素又は低級アルキル基、低級アルカノール基を表わす。Ｘはナトリウム、カリウム等のアルカリ金属を表す。）
これらはｐＨ調整で変化するが、フリーの状態はｐＨが高くアニオン染料への定着性は比較的弱いが使用可能である。

(In the above formula, R ₁ , R ₂ and R ₃ represent hydrogen or a lower alkyl group or a lower alkanol group. X represents an alkali metal such as sodium or potassium.)
Although these can be changed by pH adjustment, the free state has a high pH and the fixability to anionic dyes is relatively weak, but can be used.

Representative examples of this organic cationic compound include (A) high molecular weight compounds having primary, secondary, tertiary and quaternary nitrogen (amine or ammonium) and phosphorus (phosphonium) in the molecular chain or as pendant chains. molecular compounds, (B) low molecular weight cationic organic compounds; Specific examples of (A) include the following.

（ｍは０～３の整数、Ｒ¹，Ｒ²，Ｒ³は水素又は低級アルキル基、低級アルカノール基を表わす。）
これらは塩素など対アニオンと塩を形成したものでもよいしフリーの状態でもよい。これらの高分子カチオン性化合物は塩酸塩、酢酸塩、硝酸塩、硫酸塩等の任意の酸との化合物として用いることができる。

(m is an integer of 0 to 3, and R ¹ , R ² and R ³ each represent hydrogen, a lower alkyl group or a lower alkanol group.)
These may be in the form of a salt with a counter anion such as chlorine, or in a free state. These polymeric cationic compounds can be used as a compound with any acid such as hydrochloride, acetate, nitrate and sulfate.

Trade names of the above polymeric cationic organic compounds include Sunfix 414, 414-C555, 555US, 70, PRO-100 (manufactured by Sanyo Kasei Co., Ltd.), Protex 200, Fix K, H, SK, MCL, FM (manufactured by Satoda Kako Co., Ltd.), Moulin Fix Conc 3M (manufactured by Morin Chemical Co., Ltd.), Amigen (manufactured by Daiichi Yakuhin Kogyo Co., Ltd.), Epomin P100 (manufactured by Nippon Shokubai Co., Ltd.), Fix Oil R737, E50 (all Meisei Chemical Co., Ltd.) ), EOFIX RS (manufactured by Nicca Chemical Co., Ltd.), polyamine sulfone, polyallylamine (manufactured by Nitto Boseki Co., Ltd.), Polyfix 601 (manufactured by Showa Polymer Co., Ltd.), Nikafix D100 (manufactured by Nippon Carbide Co., Ltd.), Levogen B (manufactured by Bayer), Kaimen 557 (Dick-Hercules), and the like. If the molecular weight of these high-molecular cationic compounds is too large, the solubility becomes poor and the viscosity of the solution becomes too high. Compounds having a molecular weight of 20,000 or less containing 5 to 200 cationic groups per molecule are particularly preferred.

Specific examples of (B) include the following. ethylenediamine, hexamethylenetetramine, piperazine, 1-(2'-aminoethyl)piperidine, 1-(2'-aminoethyl)aziridine, 1-(2'-aminoethyl)pyrrolidine, 1-(2'-aminoethyl) Hexamethyleneimine, hexamethylenediamine, diethylenetriamine, triethylenetetramine, tetraethylenepentamine, N,N'-bis-(3-aminopropyl)putrescine, N-(3-aminopropyl)putrescine, 1,4-diaza Cycloheptane, 1,5-diazacyclooctane, 1,4,11,14-tetraazacycloeicosane, 1,10-diazacyclooctadecane, 1,2-diaminopropan-3-ol, 1-amino- 2,2-bis(aminomethyl)propan-1-ol, 1,3-diaminopropan-2-ol, N-(2-oxypropyl)ethylenediamine, heptaethyleneoctamine, nonaethylenedecamine, 1,3- Bis(2′-aminoethylamino)propane, triethylene-bis(trimethylene)hexaamine, 1,2-bis[3′-(2″-aminoethylamino)propylamino]ethane, bis(3-aminoethyl)amine , 1,3-bis(3′-aminopropylamino)propane, sym-homospermidine and other aliphatic or alicyclic polyvalent amines, and among these, 3 or more nitrogen atoms in one molecule. Compounds having only two nitrogen atoms are particularly preferred in the present invention, because compounds having only two or less nitrogen atoms are less likely to react with dyes to form insoluble conjugates.In addition, phenylenediamine, triaminobenzene, tetra Aromatic polyvalent amino acids such as aminobenzene, pentaaminobenzene, hexaaminobenzene, 2,6- or 2,5-diamino-p-benzoquinonediimine, and 2,3,7,8-tetraaminophenazine can also be used. good.

Methods for synthesizing these compounds are described in BARTON, OLLIS "COMPREHENSIVE ORGANIC CHEMISTRY" Peryamon Press and the like. There are no particular restrictions on the content of such organic cationic compounds in the colorless or light-colored liquid.

A solution containing an organic cationic compound is required to dry quickly after being applied to a recording medium, especially when printing at high speed. Also, the printed ink is required to permeate quickly. In order to satisfy this requirement, it is desirable to add a compound for enhancing the penetrability of the treatment liquid (organic cationic compound-containing solution) itself and/or the ink into the recording medium to the organic cationic compound-containing solution.

On the other hand, as described in JP-A-1-69381, a fourth type having at least one group selected from the group consisting of alkyl groups having 4 or more carbon atoms, alkenyl groups and aryl groups in the molecule. Ammonium salts or amine salts as well as compounds having a cationic group can be used as the treatment agent of the present invention. Penetrants used for colored inks can be used. In addition, wetting agents used in colored inks and other various additives can be used.

Next, a treatment liquid containing a polyvalent metal salt will be described. For this, the one described in Japanese Patent Application Laid-Open No. 299970/1988 can be used. A processing liquid containing a polyvalent metal salt has not only image sharpness, strike-through prevention and feathering prevention, but also a fixing function. Examples of cations in this polyvalent metal salt are aluminum Al(III), calcium Ca(II), magnesium Mg(II), copper Cu(II), iron Fe(II) and Fe(III), zinc Zn (II), tin Sn(II) and Sn(IV), strontium Sr(II), nickel Ni(II), cobalt Co(II), barium Ba(II), lead Pb(II), zirconium Zr(IV) , Titanium Ti(IV), Antimony Sb(III), Bismuth Bi(III), Tantalum Ta(V), Arsenic As(III), Cerium Ce(III), Lanthanum La(III), Yttrium Y(III), Mercury Hg(II), beryllium Be(II), and the like, among which Al(III), Ca(II), Mg(II), Zn(II), ), Fe(II), Fe(III), Sn(II), Sn(IV) are particularly preferred. In addition to these polyvalent metal ions, double salts containing monovalent cations such as alkali metals, ammonium and hydrogen can also be used.

Examples of anions include anions of halogen elements such as fluorine F, chlorine Cl, bromine Br and iodine I; nitrate ion NO ₃ ⁻ , sulfate ion SO ₄ ²⁻ ; formic acid, acetic acid, lactic acid, malonic acid, oxalic acid Anions of organic carboxylic acids such as maleic acid and benzoic acid; anions of organic sulfonic acids such as benzenesulfonic acid, naphtholsulfonic acid and alkylbenzenesulfonic acid; thiocyanate ^SCN- , thiosulfate _{S2O32- ,} phosphoric acid ion PO ₄ ^3- , nitrite ion NO ₂ ^{- and} the like.

In order to adhere a polyvalent metal salt-containing solution to a recording medium by an inkjet method, the polyvalent metal salt should be added to water and/or an organic solvent (an alcohol such as methanol, ethanol, etc.) in consideration of nozzle clogging and storage stability. ketones such as acetone and methyl ethyl ketone).

Solubility in each solution is greatly affected by anions, and Br ⁻ , I ⁻ , NO ₃ ⁻ and organic acid ions are particularly excellent in solubility among the above anions and are preferred examples.

The polyvalent metal-containing treatment liquid must be rapidly absorbed into the medium, and for this reason, it is preferable to add a penetrant. In addition, as additives that can be added to the polyvalent metal salt-containing solution, those conventionally added to inks used in ordinary ink jet recording methods can also be used. Examples include viscosity modifiers, preservatives (including antiseptic and antifungal agents), pH adjusters, and UV absorbers.

The image forming method of the present invention can be applied to any of the above coated papers, but coated papers containing no fluorescent substance in the paint are preferred so as not to interfere with fluorescence detection of the autofluorescent substance in the ink. When the coated paper contains an autofluorescent substance, it is more preferable to use a coated paper in which the fluorescent wavelength of the autofluorescent substance contained in the coated paper is different from the fluorescent wavelength of the autofluorescent substance. Fluorescent whitening agents generally used to increase the whiteness of paper are substances that emit fluorescence when irradiated with ultraviolet light, and therefore have a different fluorescence wavelength than the self-fluorescent substances such as organic pigments used in the present invention.

<Organic pigment>
The image forming method of the present invention can theoretically analyze both dye ink and pigment ink as long as the ink contains an autofluorescent substance. However, if oil is used for high-definition analysis as described above, most of the dye will dissolve in the oil, making high-definition analysis difficult. On the other hand, most pigment inks can be analyzed with high precision because the pigments used as coloring materials do not dissolve in oil.
The fluorescent substance is preferably a magenta pigment or a yellow pigment. If the fluorescent substance is a magenta pigment or a yellow pigment, the preferred ink layer can be clearly defined by confocal fluorescence microscopy.
In the image forming method of the present invention, yellow ink (excitation wavelength: 476 nm) containing organic pigment Pigment Yellow 185 or Pigment Yellow 74, magenta ink (excitation wavelength: 488 nm) containing organic pigment Pigment Red 269 or Pigment Red 122 as a fluorescent substance. ) to the image layer of the printed image. All of the above organic pigments are typical organic pigments used in water-based inks, and are substances that emit fluorescence when irradiated with visible light.

Next, a recording apparatus and a recording method for forming an ink jet image used in the image forming method of the present invention will be described.
The ink-jet image used in the present invention is formed by various ink-jet recording apparatuses, such as printers, facsimile machines, copiers, and printer/fax/copier complex machines.

A recording apparatus and a recording method refer to an apparatus capable of ejecting ink, various treatment liquids, and the like onto a recording medium, and a method of performing recording using the apparatus. A recording medium means a medium to which ink or various processing liquids can adhere even temporarily.
This recording apparatus can include not only a head portion for ejecting ink, but also means for feeding, conveying, and discharging a recording medium, and other devices called pre-processing devices and post-processing devices. .

The recording apparatus and recording method may have heating means used in the heating process and drying means used in the drying process. The heating means and drying means include, for example, means for heating and drying the printing surface and the back surface of the recording medium. The heating means and drying means are not particularly limited, but for example, hot air heaters and infrared heaters can be used. Heating and drying can be performed before, during, or after printing.
The recording apparatus and recording method are not limited to those that visualize significant images such as characters and figures with ink. For example, it also includes those that form patterns such as geometric patterns.
Unless otherwise specified, the recording apparatus includes both a serial type apparatus in which the ejection head is moved and a line type apparatus in which the ejection head is not moved.
Furthermore, this recording device can be used not only as a desktop type, but also as a wide recording device that can print on A0 size recording media, and for example, can use continuous paper wound into a roll as a recording medium. A continuous feed printer is also included.

An example of the recording apparatus will be described with reference to FIGS. 2 and 3. FIG. FIG. 2 is a perspective explanatory view of the device. FIG. 3 is a perspective explanatory view of the main tank. An image forming apparatus 400 as an example of a recording apparatus is a serial image forming apparatus. A mechanical unit 420 is provided inside the exterior 401 of the image forming apparatus 400 . Each ink container 411 of the main tank 410 (410k, 410c, 410m, 410y) for each color of black (K), cyan (C), magenta (M), and yellow (Y) is packed with, for example, an aluminum laminated film. It is made up of members. The ink containing portion 411 is housed, for example, in a container case 414 made of plastic. Thus, the main tank 410 is used as an ink cartridge for each color.

On the other hand, a cartridge holder 404 is provided on the far side of the opening when the cover 401c of the apparatus main body is opened. A main tank 410 is detachably attached to the cartridge holder 404 . As a result, each ink discharge port 413 of the main tank 410 communicates with the ejection head 434 for each color via the supply tube 436 for each color, and ink can be ejected from the ejection head 434 onto the printing medium.

The recording apparatus can include not only a portion that ejects ink, but also devices called pre-processing devices and post-processing devices.
If the treatment agent is applied to the coated paper, the pretreatment device is not necessary in principle. Preferably, the agent is brought into contact with the ink in a dissolved state. For this reason, it is preferable to provide a pretreatment device as described above so that the treatment liquid in which the treatment agent is dissolved is brought into contact with the ink before it dries. If the ink is brought into contact with the coated paper before the treatment liquid is completely dried, the ink can instantly coagulate and the scratch resistance of the image can be improved. high. At that time, if a coated paper coated with a processing agent is used, the abrasion resistance is remarkably improved.

As an aspect of the pre-treatment device and the post-treatment device, it has a pre-treatment liquid and a post-treatment liquid in the same manner as in the case of inks such as black (K), cyan (C), magenta (M), and yellow (Y). There is a mode in which a liquid container and a liquid ejection head are added, and the pretreatment liquid and the posttreatment liquid are ejected by an inkjet recording method.
As another aspect of the pre-treatment device and the post-treatment device, there is an aspect in which a pre-treatment device and a post-treatment device using a method other than the inkjet recording method, such as a blade coating method, a roll coating method, and a spray coating method, are provided.

<Pretreatment liquid>
The pretreatment liquid contains the aforementioned treatment agent, organic solvent, and water, and may optionally contain surfactants, antifoaming agents, pH adjusters, antiseptic antifungal agents, antirust agents, and the like.
Organic solvents, surfactants, antifoaming agents, pH adjusters, antiseptic antifungal agents, and antirust agents can be the same materials as those used for inks, and other materials used for known treatment liquids can be used. .

<Post-treatment liquid>
The post-treatment liquid is not particularly limited as long as it can form a transparent layer. The post-treatment liquid is obtained by selecting and mixing organic solvents, water, resins, surfactants, antifoaming agents, pH adjusters, antiseptic antifungal agents, anticorrosive agents, etc., as necessary. Further, the post-treatment liquid may be applied to the entire recording area formed on the recording medium, or may be applied only to the area where the ink image is formed.

<Ink>
Organic solvents, water, coloring materials, resins, additives, and the like used in the ink are described below.

<Organic solvent>
The organic solvent used in the present invention is not particularly limited, and any water-soluble organic solvent can be used. Examples thereof include polyhydric alcohols, ethers such as polyhydric alcohol alkyl ethers and polyhydric alcohol aryl ethers, nitrogen-containing heterocyclic compounds, amides, amines, and sulfur-containing compounds.
Specific examples of water-soluble organic solvents include ethylene glycol, diethylene glycol, 1,2-propanediol, 1,3-propanediol, 1,2-butanediol, 1,3-butanediol, and 1,4-butane. Diol, 2,3-butanediol, 3-methyl-1,3-butanediol, triethylene glycol, polyethylene glycol, polypropylene glycol, 1,2-pentanediol, 1,3-pentanediol, 1,4-pentanediol , 2,4-pentanediol, 1,5-pentanediol, 1,2-hexanediol, 1,6-hexanediol, 1,3-hexanediol, 2,5-hexanediol, 1,5-hexanediol, glycerin, 1,2,6-hexanetriol, 2-ethyl-1,3-hexanediol, ethyl-1,2,4-butanetriol, 1,2,3-butanetriol, 2,2,4-trimethyl- Polyhydric alcohols such as 1,3-pentanediol and petriol, ethylene glycol monoethyl ether, ethylene glycol monobutyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol monobutyl ether, tetraethylene glycol monomethyl ether, propylene glycol monoethyl polyhydric alcohol alkyl ethers such as ether, polyhydric alcohol aryl ethers such as ethylene glycol monophenyl ether and ethylene glycol monobenzyl ether, 2-pyrrolidone, N-methyl-2-pyrrolidone, N-hydroxyethyl-2-pyrrolidone , 1,3-dimethyl-2-imidazolidinone, ε-caprolactam, nitrogen-containing heterocyclic compounds such as γ-butyrolactone, formamide, N-methylformamide, N,N-dimethylformamide, 3-methoxy-N,N- Amides such as dimethylpropionamide and 3-butoxy-N,N-dimethylpropionamide, amines such as monoethanolamine, diethanolamine, and triethylamine, sulfur-containing compounds such as dimethylsulfoxide, sulfolane, and thiodiethanol, propylene carbonate, and ethylene carbonate. etc.
It is preferable to use an organic solvent having a boiling point of 250° C. or less because it not only functions as a wetting agent but also provides good drying properties.

Polyol compounds having 8 or more carbon atoms and glycol ether compounds are also preferably used. Specific examples of polyol compounds having 8 or more carbon atoms include 2-ethyl-1,3-hexanediol and 2,2,4-trimethyl-1,3-pentanediol.
Specific examples of glycol ether compounds include polyhydric alcohol alkyls such as ethylene glycol monoethyl ether, ethylene glycol monobutyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol monobutyl ether, tetraethylene glycol monomethyl ether, and propylene glycol monoethyl ether. Ethers; polyhydric alcohol aryl ethers such as ethylene glycol monophenyl ether, ethylene glycol monobenzyl ether, and the like.

A polyol compound having 8 or more carbon atoms and a glycol ether compound can improve ink permeability when paper is used as a recording medium.

The content of the organic solvent in the ink is not particularly limited and can be appropriately selected according to the purpose. 20% by mass or more and 60% by mass or less is more preferable.

<Water>
The content of water in the ink is not particularly limited and can be appropriately selected according to the purpose. % to 60% by mass is more preferred.

<Color material>
As described above, the image forming method of the present invention uses an ink containing a fluorescent substance, and examples of the fluorescent substance include magenta pigments and yellow pigments. In the image forming method of the present invention, an ink containing a fluorescent substance and an ink containing no fluorescent substance may be used in combination, and the coloring material of the ink containing no fluorescent substance is not particularly limited. Available.
An inorganic pigment or an organic pigment can be used as the pigment. These may be used individually by 1 type, and may use 2 or more types together. Mixed crystals may also be used.
Examples of pigments that can be used include black pigments, yellow pigments, magenta pigments, cyan pigments, white pigments, green pigments, orange pigments, glossy color pigments such as gold and silver, and metallic pigments.
As inorganic pigments, in addition to titanium oxide, iron oxide, calcium carbonate, barium sulfate, aluminum hydroxide, barium yellow, cadmium red, and chrome yellow, carbon black produced by known methods such as the contact method, furnace method, and thermal method. can be used.
Organic pigments include azo pigments, polycyclic pigments (e.g., phthalocyanine pigments, perylene pigments, perinone pigments, anthraquinone pigments, quinacridone pigments, dioxazine pigments, indigo pigments, thioindigo pigments, isoindolinone pigments, quinophthalone pigments, etc.). , dye chelates (eg, basic dye chelates, acid dye chelates, etc.), nitro pigments, nitroso pigments, aniline black, and the like. Among these pigments, those having good affinity with the solvent are preferably used. In addition, resin hollow particles and inorganic hollow particles can also be used.
Specific examples of pigments for black include carbon blacks (C.I. Pigment Black 7) such as furnace black, lamp black, acetylene black and channel black, or copper and iron (C.I. Pigment Black 11). , metals such as titanium oxide, and organic pigments such as aniline black (C.I. Pigment Black 1).
Further, for color, C.I. I. Pigment yellow 1, 3, 12, 13, 14, 17, 24, 34, 35, 37, 42 (yellow iron oxide), 53, 55, 74, 81, 83, 95, 97, 98, 100, 101, 104 , 108, 109, 110, 117, 120, 138, 150, 153, 155, 180, 185, 213, C.I. I. Pigment Orange 5, 13, 16, 17, 36, 43, 51, C.I. I. Pigment Red 1, 2, 3, 5, 17, 22, 23, 31, 38, 48:2, 48:2 (Permanent Red 2B (Ca)), 48:3, 48:4, 49:1, 52: 2, 53:1, 57:1 (brilliant carmine 6B), 60:1, 63:1, 63:2, 64:1, 81, 83, 88, 101 (red red), 104, 105, 106, 108 ( cadmium red), 112, 114, 122 (quinacridone magenta), 123, 146, 149, 166, 168, 170, 172, 177, 178, 179, 184, 185, 190, 193, 202, 207, 208, 209, 213, 219, 224, 254, 264, C.I. I. Pigment Violet 1 (rhodamine lake), 3, 5:1, 16, 19, 23, 38, C.I. I. Pigment Blue 1, 2, 15 (phthalocyanine blue), 15:1, 15:2, 15:3, 15:4 (phthalocyanine blue), 16, 17:1, 56, 60, 63, C.I. I. Pigment Green 1, 4, 7, 8, 10, 17, 18, 36, etc.
Dyes are not particularly limited, and acid dyes, direct dyes, reactive dyes, and basic dyes can be used, and may be used singly or in combination of two or more.
Examples of the dye include C.I. I. Acid Yellow 17, 23, 42, 44, 79, 142, C.I. I. Acid Red 52, 80, 82, 249, 254, 289, C.I. I. Acid Blue 9,45,249, C.I. I. Acid Black 1, 2, 24, 94, C.I. I. Food Black 1, 2, C.I. I. Direct Yellow 1, 12, 24, 33, 50, 55, 58, 86, 132, 142, 144, 173, C.I. I. Direct Red 1, 4, 9, 80, 81, 225, 227, C.I. I. Direct Blue 1, 2, 15, 71, 86, 87, 98, 165, 199, 202, C.I. I. Directed Black 19, 38, 51, 71, 154, 168, 171, 195, C.I. I. Reactive Red 14, 32, 55, 79, 249, C.I. I. and Reactive Black 3,4,35.

The content of the coloring material in the ink is preferably 0.1% by mass or more and 15% by mass or less, more preferably 1% by mass or more and 10% by mass, from the viewpoints of improving image density, good fixability, and ejection stability. It is below.

In order to disperse the pigment and obtain an ink, there are a method of introducing a hydrophilic functional group into the pigment to make it a self-dispersing pigment, a method of coating the surface of the pigment with a resin for dispersion, and a method of dispersing using a dispersant. method, etc.
As a method of making a self-dispersing pigment by introducing a hydrophilic functional group into a pigment, for example, a method of adding a functional group such as a sulfone group or a carboxyl group to a pigment (for example, carbon) to make it dispersible in water. is mentioned.
As a method of coating the surface of a pigment with a resin and dispersing it, there is a method of encapsulating the pigment in microcapsules to make it dispersible in water. This can be rephrased as a resin-coated pigment. In this case, all the pigments mixed in the ink need not be coated with a resin, and uncoated pigments or partially coated pigments may be dispersed in the ink as long as the effects of the present invention are not impaired. may be
Examples of the method of dispersing using a dispersant include a method of dispersing using a known low-molecular-weight dispersant and high-molecular-weight dispersant typified by surfactants.
As the dispersant, it is possible to use, for example, anionic surfactants, cationic surfactants, amphoteric surfactants, nonionic surfactants, etc. depending on the pigment.
RT-100 (nonionic surfactant) manufactured by Takemoto Yushi Co., Ltd. and sodium naphthalenesulfonate formalin condensate can also be suitably used as a dispersant.
A dispersing agent may be used individually by 1 type, or may use 2 or more types together.

<Pigment dispersion>
Inks can be obtained by mixing materials such as water and organic solvents with pigments. Ink can also be produced by mixing a pigment, water, a dispersant, and the like to form a pigment dispersion, and then mixing materials such as water and an organic solvent.
The pigment dispersion is obtained by mixing and dispersing water, a pigment, a pigment dispersant, and optionally other components, and adjusting the particle size. Dispersion should be carried out using a disperser.
The particle diameter of the pigment in the pigment dispersion is not particularly limited, but the dispersion stability of the pigment is improved, and the image quality such as ejection stability and image density is improved. 500 nm or less is preferable, and 20 nm or more and 150 nm or less is more preferable. The particle size of the pigment can be measured using a particle size analyzer (Nanotrack Wave-UT151, manufactured by Microtrack Bell Co., Ltd.).
The content of the pigment in the pigment dispersion is not particularly limited and can be appropriately selected according to the purpose. % or more and 50 mass % or less is preferable, and 0.1 mass % or more and 30 mass % or less is more preferable.
The pigment dispersion is preferably degassed by filtering coarse particles with a filter, a centrifugal separator, or the like, if necessary.

<Resin>
The type of resin contained in the ink is not particularly limited and can be appropriately selected according to the purpose. resins, styrene-butadiene-based resins, vinyl chloride-based resins, acrylic-styrene-based resins, acrylic-silicone-based resins, and the like.
Resin particles made of these resins may also be used. Ink can be obtained by mixing resin particles in a resin emulsion state in which water is dispersed as a dispersion medium with a material such as a coloring material or an organic solvent. As the resin particles, appropriately synthesized ones may be used, or commercially available products may be used. Moreover, these may be used individually by 1 type, or may be used in combination of 2 or more types of resin particles.

The volume average particle diameter of the resin particles is not particularly limited and can be appropriately selected according to the intended purpose. 200 nm or less is more preferable, and 10 nm or more and 100 nm or less is particularly preferable.
The volume average particle diameter can be measured, for example, using a particle size analyzer (Nanotrack Wave-UT151, manufactured by Microtrack Bell Co., Ltd.).

The content of the resin is not particularly limited and can be appropriately selected according to the purpose. However, from the viewpoint of fixability and storage stability of the ink, the content is 1% by mass or more and 30% by mass or less based on the total amount of the ink. is preferable, and 5% by mass or more and 20% by mass or less is more preferable.

The particle size of the solid content in the ink is not particularly limited and can be appropriately selected according to the purpose. is preferably 20 nm or more and 1000 nm or less, more preferably 20 nm or more and 150 nm or less. The solid content includes resin particles, pigment particles, and the like. The particle size can be measured using a particle size analyzer (Nanotrack Wave-UT151, manufactured by Microtrack Bell Co., Ltd.).

<Additive>
Surfactants, antifoaming agents, antiseptic antifungal agents, anticorrosive agents, pH adjusters, etc. may be added to the ink as necessary.

<Surfactant>
Any of silicone surfactants, fluorine surfactants, amphoteric surfactants, nonionic surfactants, and anionic surfactants can be used as surfactants.
The silicone-based surfactant is not particularly limited and can be appropriately selected depending on the purpose. Among them, those that do not decompose even at high pH are preferable. Those having an oxyethylene group or a polyoxyethylene polyoxypropylene group are particularly preferred because they exhibit good properties as water-based surfactants. As the silicone-based surfactant, a polyether-modified silicone-based surfactant can also be used, and examples thereof include compounds in which a polyalkylene oxide structure is introduced into the side chain of the Si portion of dimethylsiloxane.
Examples of fluorine-based surfactants include perfluoroalkylsulfonic acid compounds, perfluoroalkylcarboxylic acid compounds, perfluoroalkylphosphoric acid ester compounds, perfluoroalkylethylene oxide adducts, and perfluoroalkyl ether groups in side chains. Polyoxyalkylene ether polymer compounds are particularly preferred due to their low foaming properties. Examples of the perfluoroalkylsulfonic acid compound include perfluoroalkylsulfonic acid and perfluoroalkylsulfonate. Examples of the perfluoroalkylcarboxylic acid compounds include perfluoroalkylcarboxylic acids and perfluoroalkylcarboxylic acid salts. As the polyoxyalkylene ether polymer compound having a perfluoroalkyl ether group in a side chain, a sulfuric acid ester salt of a polyoxyalkylene ether polymer having a perfluoroalkyl ether group in a side chain, and a perfluoroalkyl ether group in a side chain Examples thereof include salts of polyoxyalkylene ether polymers. Counter ions of salts in these _{fluorosurfactants} include Li, Na, K, _NH4 , _NH3CH2CH2OH , _{NH2 ( CH2CH2OH} ) ₂ , and _{NH ( CH2CH2OH} ). ₃ , etc.
Examples of amphoteric surfactants include laurylaminopropionate, lauryldimethylbetaine, stearyldimethylbetaine, lauryldihydroxyethylbetaine and the like.
Nonionic surfactants include, for example, polyoxyethylene alkylphenyl ethers, polyoxyethylene alkyl esters, polyoxyethylene alkylamines, polyoxyethylene alkylamides, polyoxyethylene propylene block polymers, sorbitan fatty acid esters, polyoxyethylene sorbitan Examples include fatty acid esters and ethylene oxide adducts of acetylene alcohol.
Examples of anionic surfactants include polyoxyethylene alkyl ether acetates, dodecylbenzene sulfonates, laurates, and salts of polyoxyethylene alkyl ether sulfates.
These may be used individually by 1 type, or may use 2 or more types together.

（但し、一般式（Ｓ－１）式中、ｍ、ｎ、ａ、及びｂは、それぞれ独立に、整数を表わし、Ｒは、アルキレン基を表し、Ｒ’は、アルキル基を表す。）
上記のポリエーテル変性シリコーン系界面活性剤としては、市販品を用いることができ、例えば、ＫＦ－６１８、ＫＦ－６４２、ＫＦ－６４３（信越化学工業株式会社）、ＥＭＡＬＥＸ－ＳＳ－５６０２、ＳＳ－１９０６ＥＸ（日本エマルジョン株式会社）、ＦＺ－２１０５、ＦＺ－２１１８、ＦＺ－２１５４、ＦＺ－２１６１、ＦＺ－２１６２、ＦＺ－２１６３、ＦＺ－２１６４（東レ・ダウコーニング・シリコーン株式会社）、ＢＹＫ－３３、ＢＹＫ－３８７（ビックケミー株式会社）、ＴＳＦ４４４０、ＴＳＦ４４５２、ＴＳＦ４４５３（東芝シリコン株式会社）などが挙げられる。 The silicone-based surfactant is not particularly limited and can be appropriately selected depending on the intended purpose. Examples include polydimethylsiloxane modified at both chain ends, and polyether-modified silicone-based surfactants having polyoxyethylene groups or polyoxyethylene-polyoxypropylene groups as modifying groups exhibit excellent properties as water-based surfactants. preferable.
As such a surfactant, an appropriately synthesized one may be used, or a commercially available product may be used. Commercially available products are available from, for example, BYK Chemie Co., Ltd., Shin-Etsu Chemical Co., Ltd., Dow Corning Toray Silicone Co., Ltd., Nihon Emulsion Co., Ltd., Kyoeisha Chemical Co., Ltd., and the like.
The above polyether-modified silicone-based surfactant is not particularly limited and can be appropriately selected according to the purpose. Examples include those introduced into the side chain of the Si portion of siloxane.

(However, in general formula (S-1), m, n, a, and b each independently represent an integer, R represents an alkylene group, and R' represents an alkyl group.)
Commercially available products can be used as the above polyether-modified silicone-based surfactants. 1906EX (Japan Emulsion Co., Ltd.), FZ-2105, FZ-2118, FZ-2154, FZ-2161, FZ-2162, FZ-2163, FZ-2164 (Dow Corning Toray Silicone Co., Ltd.), BYK-33, BYK-387 (BYK-Chemie Corporation), TSF4440, TSF4452, TSF4453 (Toshiba Silicon Co., Ltd.) and the like.

上記一般式（Ｆ－１）で表される化合物において、水溶性を付与するためにｍは０～１０の整数が好ましく、ｎは０～４０の整数が好ましい。
一般式（Ｆ－２）
Ｃ_nＦ_2n+1－ＣＨ₂ＣＨ(ＯＨ)ＣＨ₂－Ｏ－(ＣＨ₂ＣＨ₂Ｏ)_a－Ｙ
上記一般式（Ｆ－２）で表される化合物において、ＹはＨ、又はＣ_mＦ_2m+1でｍは１～６の整数、又はＣＨ₂ＣＨ(ＯＨ)ＣＨ₂－Ｃ_mＦ_2m+1でｍは４～６の整数、又はＣ_pＨ_2p+1でｐは１～１９の整数である。ｎは１～６の整数である。ａは４～１４の整数である。
上記のフッ素系界面活性剤としては市販品を使用してもよい。この市販品としては、例えば、サーフロンＳ－１１１、Ｓ－１１２、Ｓ－１１３、Ｓ－１２１、Ｓ－１３１、Ｓ－１３２、Ｓ－１４１、Ｓ－１４５（いずれも、旭硝子株式会社製）；フルラードＦＣ－９３、ＦＣ－９５、ＦＣ－９８、ＦＣ－１２９、ＦＣ－１３５、ＦＣ－１７０Ｃ、ＦＣ－４３０、ＦＣ－４３１（いずれも、住友スリーエム株式会社製）；メガファックＦ－４７０、Ｆ－１４０５、Ｆ－４７４（いずれも、大日本インキ化学工業株式会社製）；ゾニール（Ｚｏｎｙｌ）ＴＢＳ、ＦＳＰ、ＦＳＡ、ＦＳＮ－１００、ＦＳＮ、ＦＳＯ－１００、ＦＳＯ、ＦＳ－３００、ＵＲ、キャプストーンＦＳ－３０、ＦＳ－３１、ＦＳ－３１００、ＦＳ－３４、ＦＳ－３５（いずれも、Ｃｈｅｍｏｕｒｓ社製）；ＦＴ－１１０、ＦＴ－２５０、ＦＴ－２５１、ＦＴ－４００Ｓ、ＦＴ－１５０、ＦＴ－４００ＳＷ（いずれも、株式会社ネオス社製）、ポリフォックスＰＦ－１３６Ａ，ＰＦ－１５６Ａ、ＰＦ－１５１Ｎ、ＰＦ－１５４、ＰＦ－１５９（オムノバ社製）、ユニダインＤＳＮ－４０３Ｎ（ダイキン工業株式会社製）などが挙げられ、これらの中でも、良好な印字品質、特に発色性、紙に対する浸透性、濡れ性、均染性が著しく向上する点から、Ｃｈｅｍｏｕｒｓ社製のＦＳ－３１００、ＦＳ－３４、ＦＳ－３００、株式会社ネオス製のＦＴ－１１０、ＦＴ－２５０、ＦＴ－２５１、ＦＴ－４００Ｓ、ＦＴ－１５０、ＦＴ－４００ＳＷ、オムノバ社製のポリフォックスＰＦ－１５１Ｎ及びダイキン工業株式会社製のユニダインＤＳＮ－４０３Ｎが特に好ましい。 As the fluorine-based surfactant, a fluorine-substituted compound having 2 to 16 carbon atoms is preferable, and a fluorine-substituted compound having 4 to 16 carbon atoms is more preferable.
Examples of fluorine-based surfactants include perfluoroalkyl phosphate ester compounds, perfluoroalkyl ethylene oxide adducts, and polyoxyalkylene ether polymer compounds having perfluoroalkyl ether groups in side chains. Among these, a polyoxyalkylene ether polymer compound having a perfluoroalkyl ether group in a side chain is preferable because of its low foamability, and in particular, fluorine-based compounds represented by general formulas (F-1) and (F-2) Surfactants are preferred.

In the compound represented by the general formula (F-1), m is preferably an integer of 0 to 10 and n is preferably an integer of 0 to 40 in order to impart water solubility.
General formula (F-2)
_{CnF2n +1} -CH2CH(OH) _{CH2 -} O-( _CH2CH2O ) _{a -} Y
In the compound represented by the general formula (F-2), Y is H, or C _m F _2m+1 and m is an integer of 1 to 6, or CH ₂ CH(OH)CH ₂ —C _m F _{2m+ 1} and m is an integer of 4 to 6, or C _p H _2p+1 and p is an integer of 1 to 19; n is an integer of 1-6. a is an integer from 4 to 14;
Commercially available products may be used as the fluorosurfactant. Examples of commercially available products include Surflon S-111, S-112, S-113, S-121, S-131, S-132, S-141, and S-145 (all manufactured by Asahi Glass Co., Ltd.); Fleurard FC-93, FC-95, FC-98, FC-129, FC-135, FC-170C, FC-430, FC-431 (both manufactured by Sumitomo 3M); Megafac F-470, F -1405, F-474 (both manufactured by Dainippon Ink and Chemicals); Zonyl TBS, FSP, FSA, FSN-100, FSN, FSO-100, FSO, FS-300, UR, Capstone FS-30, FS-31, FS-3100, FS-34, FS-35 (all manufactured by Chemours); FT-110, FT-250, FT-251, FT-400S, FT-150, FT- 400SW (all manufactured by Neos Co., Ltd.), Polyfox PF-136A, PF-156A, PF-151N, PF-154, PF-159 (manufactured by Omnova), Unidyne DSN-403N (manufactured by Daikin Industries, Ltd.) Among these, Chemours FS-3100, FS-34, FS- 300, FT-110, FT-250, FT-251, FT-400S, FT-150, FT-400SW manufactured by Neos Co., Ltd., Polyfox PF-151N manufactured by Omnova Co., Ltd. and Unidyne DSN- manufactured by Daikin Industries, Ltd. 403N is particularly preferred.

The content of the surfactant in the ink is not particularly limited and can be appropriately selected according to the purpose. % or more and 5 mass % or less is preferable, and 0.05 mass % or more and 5 mass % or less is more preferable.

<Antifoaming agent>
The antifoaming agent is not particularly limited, and examples thereof include silicone antifoaming agents, polyether antifoaming agents, and fatty acid ester antifoaming agents. These may be used individually by 1 type, or may use 2 or more types together. Among these, silicone-based antifoaming agents are preferred because of their excellent foam breaking effect.

<Preservative and antifungal agent>
The antiseptic and antifungal agent is not particularly limited, and examples thereof include 1,2-benzisothiazolin-3-one.

<Antirust agent>
The rust inhibitor is not particularly limited, and examples thereof include acidic sulfites and sodium thiosulfate.

<pH adjuster>
The pH adjuster is not particularly limited as long as it can adjust the pH to 7 or higher, and examples thereof include amines such as diethanolamine and triethanolamine.

The physical properties of the ink are not particularly limited and can be appropriately selected depending on the intended purpose. For example, viscosity, surface tension, pH and the like are preferably within the following ranges.
The viscosity of the ink at 25° C. is preferably 5 mPa·s or more and 30 mPa·s or less, more preferably 5 mPa·s or more and 25 mPa·s or less, from the viewpoint of improving the print density and character quality and obtaining good ejection properties. more preferred. Here, the viscosity can be measured using, for example, a rotational viscometer (RE-80L manufactured by Toki Sangyo Co., Ltd.). Measurement conditions are 25° C., standard cone rotor (1°34′×R24), sample liquid volume 1.2 mL, rotation speed 50 rpm, 3 minutes.
The surface tension of the ink is preferably 35 mN/m or less, more preferably 32 mN/m or less at 25° C., from the viewpoint that the ink is appropriately leveled on the recording medium and the drying time of the ink is shortened.
The pH of the ink is preferably from 7 to 12, more preferably from 8 to 11, from the viewpoint of preventing corrosion of metal members in contact with the liquid.

In the present invention, the terms image formation, recording, printing, and printing are all synonymous.

The terms recording medium, medium, and printed material are all synonymous.

Examples of the present invention will be described below, but the present invention is not limited to these examples. Further, the numerical values in the table indicate "% by mass".

<Preparation of pigment dispersion 1>
After sufficiently purging the inside of a 1 L flask equipped with a mechanical stirrer, thermometer, nitrogen gas inlet tube, reflux tube and dropping funnel with nitrogen gas, 11.2 g of styrene, 2.8 g of acrylic acid and 12.0 g of lauryl methacrylate were added. , 4.0 g of polyethylene glycol methacrylate, 4.0 g of styrene macromer and 0.4 g of mercaptoethanol were mixed and heated to 65°C. Next, styrene 100.8 g, acrylic acid 25.2 g, lauryl methacrylate 108.0 g, polyethylene glycol methacrylate 36.0 g, hydroxylethyl methacrylate 60.0 g, styrene macromer 36.0 g, mercaptoethanol 3.6 g, azobismethylvalero. After dropping a mixed solution of 2.4 g of nitrile and 18 g of methyl ethyl ketone into the flask over 2.5 hours, a mixed solution of 0.8 g of azobismethylvaleronitrile and 18 g of methyl ethyl ketone was poured into the flask over 0.5 hours. It was added dropwise and aged at 65° C. for 1 hour. Further, 0.8 g of azobismethylvaleronitrile was added, and after aging for 1 hour, 364 g of methyl ethyl ketone was added into the flask to obtain 800 g of a 50% by mass polymer solution.
28 g of the polymer solution, 42 g of a magenta pigment (CI Pigment Red 122/toner magenta EO02, manufactured by Clariant), 13.6 g of a 1 mol/L potassium hydroxide aqueous solution, 20 g of methyl ethyl ketone, and 13.6 g of deionized water were sufficiently prepared. After stirring, the mixture was kneaded using a roll mill to obtain a paste. Next, the paste was poured into 200 g of pure water and thoroughly stirred, and then methyl ethyl ketone and water were distilled off using an evaporator. Further, pressure filtration was performed using a polyvinylidene fluoride membrane filter having an average pore size of 5.0 μm to obtain a magenta pigment dispersion 1 having a pigment content of 15% by mass and a solid content of 20% by mass.

<Preparation of pigment dispersion 2>
(Synthesis of copolymer)
-Synthesis of Monomer M-a1-
62.0 g (525 mmol) of 1,6-hexanediol (manufactured by Tokyo Kasei Kogyo Co., Ltd.) was dissolved in 700 mL of methylene chloride, and 20.7 g (262 mmol) of pyridine was added.
To this solution, a solution of 50.0 g (262 mmol) of 2-naphthalenecarbonyl chloride (manufactured by Tokyo Chemical Industry Co., Ltd.) dissolved in 100 mL of methylene chloride was added dropwise with stirring over 2 hours, and then at room temperature for 6 hours. Stirred. After washing the resulting reaction solution with water, the organic phase is isolated, dried over magnesium sulfate and evaporated. The residue was purified by silica gel column chromatography using a mixed solvent of methylene chloride/methanol (volume ratio 98/2) as an eluent to obtain 52.5 g of a reaction intermediate of the following structural formula (I-1). rice field.

Next, 41.0 g (151 mmol) of the reaction intermediate of the structural formula (I-1) was dissolved in 250 mL of methylene chloride, and 20.0 g (198 mmol) of triethylamine (manufactured by Tokyo Chemical Industry Co., Ltd.) was added. . This solution was cooled in an ice bath, and 20.0 g (191 mmol) of methacrylic acid chloride (manufactured by Tokyo Chemical Industry Co., Ltd.) was added dropwise over 30 minutes. Stirred. After filtering off the precipitate and washing the filtrate with water, saturated aqueous sodium hydrogen carbonate solution and saturated brine, the organic phase was isolated, dried over magnesium sulfate and evaporated. The residue was purified by silica gel column chromatography using a mixed solvent of n-hexane/ethyl acetate (volume ratio 6/1) as an eluent to obtain 39.4 g of monomer M-a1.

-Synthesis of Copolymer CP-1-
A monomer solution was prepared by dissolving 20.3 g (282 mmol) of acrylic acid (manufactured by Tokyo Chemical Industry Co., Ltd.) and 79.7 g (234 mmol) of monomer M-a1 in 500 mL of dry methyl ethyl ketone. After heating 10% by mass of the monomer solution to 75 ° C. under an argon stream, 5.0 g of 2,2'-azobis(isobutyronitrile) (AIBN, manufactured by Tokyo Chemical Industry Co., Ltd.) was added to the remaining monomer solution. The dissolved solution was added dropwise over 2 hours and stirred at 75° C. for 6 hours. After cooling to room temperature, the resulting reaction solution was dropped into hexane. The precipitated copolymer was separated by filtration and dried under reduced pressure to obtain 95.7 g of [Copolymer CP-1] (weight average molecular weight (Mw): 22,500).

(Preparation of pigment dispersion 2)
4.0 parts by mass of copolymer CP-1 was dissolved in 80.0 parts by mass of tetraethylammonium hydroxide aqueous solution so that the pH was 8.0. To 84.0 parts by mass of the resulting copolymer aqueous solution, 16.0 parts by mass of a magenta pigment (C.I. Pigment Red 122/Toner Magenta EO02, manufactured by Clariant) was added and stirred for 12 hours.
The resulting mixture was circulated and dispersed for 1 hour at a peripheral speed of 10 m/s using a disk-type bead mill (manufactured by Shinmaru Enterprises, model KDL, media: using zirconia balls with a diameter of 0.1 mm), and then the average pore size was measured. After filtration through a 1.2 μm membrane filter, an adjusted amount of ion-exchanged water was added to obtain 97.0 parts by mass of [Pigment Dispersion 2] (pigment solid content concentration: 16% by mass).

(Ink manufacturing example)
Inks 1 to 4 were prepared by mixing and stirring the materials shown in each column of Table 1 below in a beaker.

The surfactants, acrylic resin emulsions, and urethane resin emulsions shown in Table 1 are as follows.
Surfactant:
BYK-348; manufactured by BYK-Chemie, polyether-based polysiloxane surfactant FZ-2146; manufactured by Dow Corning Toray Silicone Co., Ltd.,
Polyether-modified silicone surfactant Tego wet-270; manufactured by Evonik,
Polyether-modified polysiloxane surfactant acrylic resin emulsion: Polysol ROY6312, manufactured by Showa Kobunshi Co., Ltd.,
Acrylic-silicone resin emulsion with a minimum film-forming temperature (MFT) of 20° C. Urethane resin emulsion: W5661, manufactured by Mitsui Chemicals Polyurethanes, Ltd.
Polyurethane resin emulsion

(Manufacturing example of treatment liquid)
The materials shown in each column of Table 2 below were mixed and stirred in a beaker to prepare treatment liquids 1 to 6.

In Table 2, "Himax SC-506" and "LS-106" are as follows.
LS-106: Emulgen LS-106
(Polyoxyethylene polyoxypropylene alkyl ether, manufactured by Kao Corporation)
Himax SC-506: cationic resin (trade name: Himax SC-506, manufactured by Hymo, cation equivalent 5.0 meq/g)

Example 1
0.9 g/m ² of treatment liquid 2 was applied to the coated surface of OK Kinto+104.7 GMS (manufactured by Oji Paper Co., Ltd.) by a roller coating method, and then dried in a constant temperature bath at 90° C. for 30 seconds.
Under an environment of 23° C. and 50% RH, ink 3 and treatment liquid 1 are filled in an inkjet printer (manufactured by Ricoh Co., Ltd., modified IPSiO GX5000 (equipped with a pre-treatment device for applying treatment liquid)), and an aqueous inkjet recording method is performed. A solid image was formed by ejecting treatment liquid 1 and ink 3 at a single pass of 600 dpi (120 m/min).
The thickness of the ink layer was 2.0 μm.

<Evaluation of fixability>
The solid image obtained by the above procedure was dried for 180 seconds in a constant temperature dryer (OF-300B manufactured by AS ONE Co., Ltd.) at 100° C. after printing. Using a crockmeter (manufactured by Daiei Kagaku Seiki Seisakusho), paper (Lumi Art Gross (90 gms)) was rubbed against the printed solid portion 10 times, and the transfer of the pigment to the paper was visually observed. No transfer to paper was observed.

<Observation with a confocal fluorescence microscope>
A portion of the printed image was cut out with scissors and fixed on a slide glass with double-sided tape. An appropriate amount of salad oil (Nissin Salad Oil, manufactured by Nisshin OilliO) was dropped from the top, and a cover glass was placed thereon. This was observed with an inverted confocal fluorescence microscope TCS SP8 (manufactured by Leica) to visualize the three-dimensional shape of the inkjet image layer. The measurement conditions are as follows.
・Light source Argon laser 488 nm
・Light receiving wavelength 500-620nm
・Objective lens Oil immersion lens HC PLAPO CS2 (NA1.4)
・Detector: HyD Photon Counting mode ・Pinhole diameter: 32.2 μm
・Field diameter X×Y=18.45 μm×18.45 μm
・Z step 0.1545 μm
・Number of pixels X×Y×Z=512×512×86
(n1=512, n2=512, n3=86)
・Scan speed 400Hz
・Zoom 10 times After the measurement, data in the Z direction of each F (X, Y) were superimposed (average of fluorescence intensity) by the Maximum projection function to obtain F' (Xi, Yj). The results are shown in FIG. The brightness in the figure represents the fluorescence intensity, the brighter the fluorescence intensity is, the darker the fluorescence intensity is, the weaker the fluorescence intensity. In FIG. 4, F' (Xi, Yj) extracted the point where 75% or less of the average fluorescence intensity (F'ave) of all F' (Xi, Yj) (512 × 512 = 262144) By the way, it became like FIG. 5 and the ratio was 3.54%.

Example 2
A solid image was formed in the same manner as in Example 1 except that ink 3 was replaced with ink 4 and treatment liquid 1 was replaced with treatment liquid 2, and fixability was evaluated in the same manner as in Example 1. No transfer to paper was observed. Observation with a confocal fluorescence microscope was carried out, and the percentage of portions where the average fluorescence intensity (F'ave) was 75% or less was found to be 2.18%.

Comparative example 1
In Example 1, a solid image was formed in the same manner as in Example 1 except that ink 3 was replaced with ink 1 and treatment liquid 1 was replaced with treatment liquid 2. Fixability was evaluated in the same manner as in Example 1. Significant transfer to paper was observed. Observation with a confocal fluorescence microscope was also carried out, and the percentage of portions where the average fluorescence intensity (F'ave) was 75% or less was found to be 0.03%.

Example 3
A solid image was formed in the same manner as in Example 2, except that OK Kinto + 104.7 GMS (manufactured by Oji Paper Co., Ltd.) coated with Treatment Liquid 2 was used as Lumi Art Gross (90 gms), and fixability was evaluated. No transfer to the paper was observed. Observation with a confocal fluorescence microscope was also carried out, and the ratio of locations where the average fluorescence intensity (F'ave) was 75% or less was found to be 3.71%.

Example 4
In Example 3, a solid image was formed in the same manner as in Example 3 except that treatment liquid 2 was changed to treatment liquid 5, and fixability was evaluated. , was at an acceptable level. Observation with a confocal fluorescence microscope was also carried out, and the percentage of portions where the average fluorescence intensity (F'ave) was 75% or less was found to be 8.55%.

Comparative example 2
In Example 3, a solid image was formed in the same manner as in Example 3 except that treatment liquid 2 was changed to treatment liquid 6, and fixability was evaluated. Met. Further, observation was carried out using a confocal fluorescence microscope, and the ratio of locations where the average fluorescence intensity (F'ave) was 75% or less was found to be 9.37%.

Example 5
1.8 g/m ² of treatment liquid 2 was applied to the coated surface of Lumi Art Gloss (90 gms) by a roller coating method, and then dried in a constant temperature bath at 90° C. for 30 seconds.
A solid image was formed in the same manner as in Example 1 except that the above paper was used in place of OK Kinto +104.7 GMS (manufactured by Oji Paper Co., Ltd.) coated with treatment liquid 2, and fixability was evaluated. , the transfer to the paper was slightly observed, but it was at an acceptable level. Observation with a confocal fluorescence microscope was also carried out, and the ratio of portions where the average fluorescence intensity (F'ave) was 75% or less was found to be 0.08%.

Example 6
1.8 g/m ² of treatment liquid 1 was applied to the coated surface of Lumi Art Gloss (90 gms) by a roller coating method, and then dried in a constant temperature bath at 90° C. for 30 seconds.
In Example 5, a solid image was formed in the same manner as in Example 5 except that the above paper was used, and fixability was evaluated. As a result, transfer to the paper was not observed. Observation with a confocal fluorescence microscope was also carried out, and the percentage of portions where the average fluorescence intensity (F'ave) was 75% or less was found to be 0.12%.

Example 7
In Example 2, a solid image was formed in the same manner as in Example 2 except that only OK Kinto + 104.7 GMS (manufactured by Oji Paper Co., Ltd.) was used as the paper, and fixability was evaluated. I didn't. Observation with a confocal fluorescence microscope was also carried out, and the ratio of locations where the average fluorescence intensity (F'ave) was 75% or less was found to be 2.68%.

Example 8
In Example 7, a solid image was formed in the same manner as in Example 7 except that Treatment Liquid 3 was used as the treatment liquid, and fixability was evaluated. As a result, transfer to paper was not observed. Observation with a confocal fluorescence microscope was also carried out, and the percentage of locations where the average fluorescence intensity (F'ave) was 75% or less was found to be 1.19%.

Comparative example 3
In Example 8, a solid image was prepared in the same manner as in Example 8 except that ink 2 was used, and fixability was evaluated. Observation with a confocal fluorescence microscope was carried out, and the percentage of portions where the average fluorescence intensity (F'ave) was 75% or less was found to be 0.02%.

(About Figure 1)
REFERENCE SIGNS LIST 1 lamp 2 illumination lens 3 objective lens 4 dichroic mirror 5 point light source 7 focal plane 8 detector 9 sample

(About Figures 2 and 3)
400 Image forming apparatus 401 Exterior of image forming apparatus 401c Cover of apparatus main body 404 Cartridge holder 410 Main tank 410k, 410c, 410m, 410y For black (K), cyan (C), magenta (M), and yellow (Y) main tank 411 ink storage unit 413 ink discharge port 414 storage container case 420 mechanism unit 434 ejection head 436 supply tube

(About Figure 4)
21 supply roll 22 recording medium 23a, 23b, 23c, 23d printing unit 24a, 24b, 24c, 24d light source 25 processing unit 26 print take-up roll

JP-A-56-86789 JP-A-55-150396 Japanese Patent Application Laid-Open No. 2003-182203 JP-A-2002-310956 Japanese Patent Application Laid-Open No. 2006-322881 JP 2005-127938 A

Claims (4)

Organic pigments capable of emitting fluorescence containingwater systemAn image forming method for forming an image on a printing material using ink,
A water-based pretreatment liquid application step of applying a water-based pretreatment liquid formed by dissolving a treatment agent on the surface of the printing material;
a heating step of heating the water-based pretreatment liquid applied to the surface of the substrate to evaporate the liquid component;
a step of applying the water-based ink to the surface to which the water-based pretreatment liquid has been applied before the water-based pretreatment liquid is completely dried by the heating step;
has
The material to be printed is coated paper,
The treatment agent has a function of aggregating the water-based ink,
Fluorescence intensity F (Xi, Yj, Zk) measured by a confocal fluorescence microscope
(However, i = 1 to n1, j = 1 to n2, k = 1 to n3, k = 1 represents the position of the bottom surface of the image in the Z direction, and k = n3 represents the position of the top surface of the image in the Z direction.)
In F'(Xi, Yj) and F'ave obtained by the following formula from

F'(Xi, Yj) ≤ 0.75 x F'ave
An image forming method for forming an image in which F'(Xi, Yj) is 0.05 to 9.00% of the total F'(Xi, Yj). 2. The image forming method according to claim 1, wherein the organic pigment is a magenta pigment or a yellow pigment. 3. The image forming method according to claim 1, wherein the image forming method is a method of forming an image by ejecting the water -based ink. A printed matter having an image on a substrate,
The material to be printed is coated paper,
The pigment contained in the printed material is an organic pigment capable of emitting fluorescence,
SaidFluorescence intensity F (Xi, Yj, Zk) measured by a confocal fluorescence microscope
(However, i = 1 to n1, j = 1 to n2, k = 1 to n3, k = 1 represents the position of the bottom surface of the image in the Z direction, and k = n3 represents the position of the top surface of the image in the Z direction.)
In F'(Xi, Yj) and F'ave obtained by the following formula from

F'(Xi, Yj) ≤ 0.75 x F'ave
F'(Xi, Yj) is 0.05 to 9.00% of the total F'(Xi, Yj).

Images