JP2022047317A - Liquid ejection system - Google Patents

Abstract

To provide a liquid ejection system that can acquire a high-quality and high-definition image and reduce an amount of ink mist generation.SOLUTION: A liquid ejection system includes: a first liquid ejection head for ejecting first ink; and a second liquid ejection head that ejects second ink having the same color as the first ink and has an amount of mist generated when ejecting the second ink that is less than the first liquid ejection head.SELECTED DRAWING: Figure 1

Description

The present invention relates to a liquid discharge system.

Conventionally, a liquid ejection device that forms an image on a medium such as paper by ejecting a liquid such as ink has been known. Further, it is known that in such a liquid discharge device, mist (ink mist) is generated when the liquid is discharged. The ink mist refers to a plurality of minute droplets generated accompanying the droplets ejected from the ejection port. Ink mist increases due to the miniaturization of droplets and may adhere to the ejection port surface of the liquid ejection head, causing problems such as ejection defects. Further, if the mist scatters and adheres to the print media, it causes a factor of quality deterioration.

Therefore, conventionally, in order to reduce the influence of ink mist, a liquid discharge device in which the arrangement position and spacing of the liquid discharge heads are devised, and a wiping device that wipes the ink mist adhering to the discharge port surface for each one or a plurality of media. A liquid discharge device including the above has been proposed (see, for example, Patent Documents 1 and 2).

By the way, the amount of ink mist generated changes according to the amount of liquid (ink) discharged, and when a large amount of liquid is discharged, the amount of ink mist generated also increases. However, with the above-mentioned conventional technique, the amount of ink mist generated cannot be reduced, and there is room for further improvement.

Therefore, if a liquid discharge device, a liquid discharge method, and a program that can reduce the amount of mist generated can be used, the generation of mist itself can be suppressed, but the wet spread of solid parts and the like deteriorates, leading to a decrease in image density. There is a problem that it will be closed.

An object of the present invention is to provide a liquid ejection system capable of obtaining high-quality and high-definition images and reducing the amount of ink mist generated.

The above problem is solved by the following configuration 1).
1) The first liquid ejection head that ejects the first ink,
With the second liquid ejection head, the amount of mist generated when the second ink of the same color as the first ink is ejected and the second ink is ejected is smaller than that of the first liquid ejection head. ,
A liquid discharge system characterized by being equipped with.

According to the present invention, it is possible to provide a liquid ejection system capable of obtaining high-quality and high-definition images and reducing the amount of ink mist generated.

FIG. 1 is a perspective explanatory view when a cassette is attached to the image forming apparatus of the image giving apparatus according to the embodiment. FIG. 2 is a perspective explanatory view when the cassette is removed and inserted into the heating device after image formation by the image forming device of the image giving device according to the embodiment. FIG. 3 is a perspective explanatory view illustrating the overall configuration of the mechanical portion of the image forming apparatus according to the embodiment. FIG. 4 is a perspective explanatory view illustrating the overall configuration of the mechanical portion of the image forming apparatus viewed from a direction different from that of FIG. FIG. 5 is a diagram schematically showing a configuration example of a carriage included in the image forming apparatus of the embodiment. FIG. 6 is a diagram showing an example of the configuration of the control unit of the image forming apparatus according to the embodiment. FIG. 7 is a diagram showing an example of the functional configuration of the image forming apparatus according to the embodiment. FIG. 8 is a diagram for explaining a liquid discharge head. FIG. 9 is a perspective explanatory view showing an example of an inkjet recording device. FIG. 10 is a perspective explanatory view showing an example of a main tank in an inkjet recording device.

Hereinafter, embodiments of the liquid discharge system will be described with reference to the drawings.
First, with reference to FIGS. 1 and 2, an example of an image imparting device as a liquid discharge system according to the present embodiment will be described with reference to FIGS. 1 and 2. FIG. 1 is a perspective explanatory view when the cassette 200 is attached to the image forming apparatus 1 of the image giving apparatus 1000. FIG. 2 is a perspective explanatory view when the cassette 200 is removed and inserted into the heating device 500 after the image is formed by the image forming device 1 of the image giving device 1000.

The image imparting device (liquid ejection system) 1000 includes a cassette 200, an image forming device 1, and a heating device 500. The cassette 200 is a member that holds the printed portion of the fabric 400, which is a medium, in a flat state, and is shared by both the image forming apparatus 1 and the heating apparatus 500.

The image forming apparatus 1 is an example of a liquid discharging apparatus. In the image forming apparatus 1, the cassette 200 is detachable, and an image is formed on the cloth 400 held in the cassette 200. In the heating device 500, the cassette 200 is removable, and the fabric 400 on which the image is formed is heated together with the cassette 200 to fix the image.

Although the image forming apparatus 1 is shown here in a state where the image forming apparatus 1 is placed on the heating apparatus 500, the image forming apparatus 1 and the heating apparatus 500 are separate bodies and may be arranged side by side or arranged side by side. It can also be placed at a remote location.

When an image is imparted to the fabric 400 by the image imparting device 1000, as shown in FIG. 1, the cassette 200 holding the fabric 400 is set (mounted) on the stage 111 of the image forming apparatus 1, and the fabric is set (mounted) by the image forming apparatus 1. An image is formed at 400.

When the image formation by the image forming apparatus 1 is completed, the front door 502 of the heating device 500 is opened, the cassette 200 holding the fabric 400 is taken out from the image forming apparatus 1, and the cassette 200 is taken out as it is, as shown in FIG. 200 is inserted into the heating device 500. Then, after the cassette 200 is housed in the heating device 500, the front door 502 of the heating device 500 is closed, and the heating device 500 heats the fabric 400 together with the cassette 200. The image formed on the cloth 400 by heating the cloth 400 is fixed on the cloth 400.

Next, a configuration example of the image forming apparatus 1 will be described with reference to FIGS. 3 to 5. FIG. 3 is a perspective explanatory view illustrating the overall configuration of the mechanical portion of the image forming apparatus 1. FIG. 4 is a perspective explanatory view illustrating the overall configuration of the mechanical portion of the image forming apparatus 1 as viewed from a direction different from that of FIG. FIG. 5 is a diagram schematically showing a configuration example of a carriage 121 included in the image forming apparatus 1.

The image forming apparatus 1 is held in a stage 111, which is a receiving member that detachably holds a cassette 200 holding the fabric 400 and moves back and forth in the apparatus main body 100, and a cassette 200 held by the stage 111. The fabric 400 is provided with an image forming unit 112 that forms an image.

Here, the cloth 400 is not only a piece of cloth such as a handkerchief or a towel, but also a part of a product such as a cloth processed as clothes such as a T-shirt or a trainer, or a tote bag. You can also use the existing fabric.

The stage 111 is provided on the transport structure 113 held so as to be reciprocally movable in the arrow Y direction (sub-scanning direction) with respect to the apparatus main body 100. Specifically, the stage 111 is connected to the transport structure 113, and the slider portion 116 of the transport structure 113 is arranged on the bottom housing portion 114 of the apparatus main body 100 along the arrow Y direction. It is held movable by. The stage 111 (conveying structure 113) is reciprocated in the arrow Y direction by the sub-scanning motor M2 (see FIG. 6).

The image forming unit 112 includes a carriage 121 that moves in the arrow X direction (main scanning direction) with respect to the stage 111. The carriage 121 is movably held by a guide member 123 arranged along the arrow X direction, and is reciprocated in the arrow X direction by the main scanning motor M1 via a scanning mechanism unit such as a timing belt 125. Further, the carriage 121 is equipped with a liquid ejection head 122 that ejects ink onto the surface of the fabric to form an image.

For example, as shown in FIG. 5, a plurality of liquid discharge heads 122 (122c, 122m, 122y, 122k, 122w1, 122w2) are mounted on the carriage 121. Each of the liquid ejection heads 122 has a large number of nozzles (discharging ports) for ejecting ink that is a liquid, and is arranged in the arrow X direction (main scanning direction) with respect to the stage 111.

In the present invention, a first liquid ejection head for ejecting the first ink and a second ink having the same color as the first ink are ejected, and mist generated when the second ink is ejected is generated. It comprises a second liquid discharge head, the amount of which is smaller than that of the first liquid discharge head.
The same color as used in the present invention means that "the pigments contained in the ink are the same pigment type".
The liquid discharge head has discharge nozzle plates 4a and 4b as shown in FIG. Each discharge nozzle plate has two nozzle rows Na and Nb in which a plurality of nozzles 4n are arranged on the nozzle forming surface 41. The number of nozzle rows is not limited to two. Any number of nozzle rows can be provided in consideration of the size of the printing apparatus. As the liquid discharge head, for example, a piezoelectric actuator such as a piezoelectric element or a thermal actuator that utilizes a phase change due to boiling of a liquid film by using an electric heat conversion element such as a heat generating resistor can be used.

The liquid ejection head 122c ejects cyan ink. The liquid ejection head 122m ejects magenta ink. The liquid ejection head 122y ejects yellow ink. The liquid ejection head 122k ejects black ink. Further, both the liquid discharge head 122w1 and the liquid discharge head 122w2 discharge white ink. The ink of each color is supplied to each of the liquid discharge heads 122 from the tank mounted on the carriage 121 for each color. The color and number of inks may be arbitrary and can be changed as needed.

Here, the liquid discharge head 122w1 and the liquid discharge head 122w2 correspond to the first liquid discharge head and the second liquid discharge head. The amount of mist (ink mist) generated when ink is discharged differs between the liquid discharge head 122w1 and the liquid discharge head 122w2. Specifically, the amount of mist generated when the same amount of ink is ejected (hereinafter, also referred to as the amount of mist generated) is smaller in the liquid ejection head 122w2 than in the liquid ejection head 122w1.

Various methods can be adopted regardless of the specification difference between the liquid discharge head 122w1 and the liquid discharge head 122w2, which are related to the difference in the amount of mist generated. For example, the liquid discharge head 122w1 and the liquid discharge head 122w2 may have different mechanisms (for example, the size of the discharge port) for discharging the liquid. Further, for example, the liquid discharge head 122w1 and the liquid discharge head 122w2 may have the same mechanism, and the drive waveforms of the drive signals may be different, that is, the ink discharge speed may be different, so that the amount of mist generated may be different. ..

In the present embodiment, the liquid ejection heads 122w1 and the liquid ejection heads 122w2 having different mist generation amounts are filled with white ink 1 and white ink 2 having different dynamic surface tensions. The dynamic surface tension of the white ink 2 is larger than that of the white ink 1, and the amount of mist generated during ejection is suppressed. Therefore, by combining with the liquid discharge head 122w2 having a small amount of mist generation, it is possible to further suppress the amount of mist generated. When the generation of mist is suppressed, the amount of splashes on the printed matter is reduced, and even highly delicate images can be clearly depicted. In addition, since the amount of droplets scattered in the machine is reduced, the inside of the machine is less contaminated, and the nozzle surface is less contaminated, which improves maintainability and enables stable ejection over a long period of time.

On the other hand, if ink with a large dynamic surface tension is used to suppress the generation of mist, the wet spread of the ink on the media becomes worse and the image filling worsens, and the image density OD decreases with the color ink. It ends up. In the case of the white ink of the present embodiment, the hiding rate of the base is deteriorated, and the readability of other inks superimposed on the white ink may be deteriorated.

Therefore, the liquid ejection head 122w1 that generates a large amount of mist is filled with ink having a small dynamic surface tension, and the portion that requires high OD or large area printing is printed by using the liquid ejection head 122w1. It is possible to print with a head and ink suitable for the image while controlling the amount.

In the present invention, the dynamic surface tension of the first ink at a life time of 15 ms (25 ° C.) is 30 [mN / m] or more and 50 [mN / m] or less, and the life time is 15 ms (25 ° C.). The dynamic surface tension of the second ink can be 50 [mN / m] or more and less than 70 [mN / m]. Here, the surface tension means a dynamic surface tension. The dynamic surface tension can be controlled by the type and amount of the surfactant added.
The difference between the dynamic surface tension of the first ink and the dynamic surface tension of the second ink is, for example, 5 [mN / m] or more and 40 [mN / m] or less, and 10 [mN / m]. It is preferably m] or more and 35 [mN / m] or less.

From the viewpoint of adjusting the dynamic surface tension and improving the effect of the present invention, the amount of the surfactant of the first ink is 0.1 [mass%] or more and 1 [mass%] or less. Is preferable. The amount of the surfactant in the second ink is preferably 0.5 [mass%] or less.

The dynamic surface tension can be measured by a well-known and conventional method, but in the present invention, it is preferably measured by the maximum foam pressure method. A measuring instrument for dynamic surface tension by the maximum method of pressure is commercially available, and examples thereof include DynoTeter (manufactured by SITA).
The maximum bubble pressure method is a method in which bubbles are discharged from the tip portion of a probe immersed in a liquid to be measured, and the surface tension is obtained from the maximum pressure required to release the bubbles.
When the radius of the bubble is equal to the radius of the probe tip, the maximum pressure is shown, and the dynamic surface tension σ of the ink at this time is expressed by the following equation.

σ = (ΔP ・ r) / 2
(Here, r is the radius of the probe tip, and ΔP is the difference between the maximum pressure applied to the bubble and the minimum value.)

Further, the life time referred to in the present invention means the time from when the bubbles are separated from the probe and a new surface is formed to the next maximum bubble pressure in the maximum bubble pressure method.

Returning to FIGS. 3 and 4, in the image forming apparatus 1, the cassette 200 is mounted and held on the stage 111 in the apparatus main body 100 in a state where the fabric 400 is set on the platen member 300 of the cassette 200. Then, the required image is printed on the cloth 400 by repeating the movement of the stage 111 in the arrow Y direction and the reciprocating movement of the liquid discharge head 122 in the arrow X direction.

In this case, the stage 111 can be raised and lowered in the arrow Z direction by the stage raising and lowering motor M3 (see FIG. 6), and the stage 111 is moved up and down according to the thickness of the cloth 400, whereby the gap between the cloth 400 and the liquid discharge head 122 is reached. Can be adjusted to a predetermined gap. The image forming unit 112 may be configured to be able to move up and down.

Next, with reference to FIG. 6, the configuration of the control unit of the image forming apparatus 1 described above will be described. Here, FIG. 6 is a diagram showing an example of the configuration of the control unit of the image forming apparatus 1.

As shown in FIG. 6, the control unit 700 includes a CPU (Central Processing Unit) 701, a ROM (Read Only Memory) 702, a RAM (Random Access Memory) 703, an NVRAM (Non-Volatile RAM) 704, and an ASIC705. And have.

The CPU 701 comprehensively controls the entire image forming apparatus 1. The ROM 702 is a memory for storing a program executed by the CPU 701 and other fixed data. The RAM 703 is a memory for temporarily storing image data, print data, and the like. Here, the CPU 701, ROM 702, and RAM 703 correspond to the main control unit 700A (computer) of the image forming apparatus 1.

The NVRAM 704 is a non-volatile memory capable of holding data even while the power of the image forming apparatus 1 is cut off. The ASIC 705 processes various signal processing, image processing for rearranging, and other input / output signals for controlling the entire image forming apparatus 1.

Further, the control unit 700 includes a host I / F 706, an I / O 707, a head drive control unit 708, a main scanning motor drive unit 709, a sub-scanning motor drive unit 710, and an elevating motor drive unit 711.

The host I / F706 sends / receives data and signals to / from the host H side. The head drive control unit 708 generates a drive waveform for driving and controlling the liquid discharge head 122.

The main scanning motor drive unit 709 drives the main scanning motor M1. The main scanning motor M1 moves the carriage 121 in the X direction by driving. The sub-scanning motor drive unit 710 drives the sub-scanning motor M2. The sub-scanning motor M2 moves the stage 111 in the Y direction by driving. The elevating motor drive unit 711 drives the stage elevating motor M3. The stage elevating motor M3 elevates and elevates the stage 111 in the Z direction by driving.

The I / O 707 acquires information from various sensors (temperature sensors and the like) provided in the image forming apparatus 1, and extracts information necessary for controlling each part of the image forming apparatus 1. Further, an operation panel 712 for inputting and displaying various information is connected to the control unit 700.

The control unit 700 transfers image data from the host H side such as an information processing device such as a PC (Personal Computer), an image reading device such as an image scanner, and an image pickup device such as a digital camera to the host I / F706 via a cable or a network. Receive at. The CPU 701 and the ASIC 705 analyze the image data received by the host I / F 706 and generate print data.

Next, with reference to FIG. 7, the functional configuration of the image forming apparatus 1 described above will be described. Here, FIG. 7 is a diagram showing an example of the functional configuration of the image forming apparatus 1.

As shown in FIG. 7, the image forming apparatus 1 has an acquisition unit 801, a generation unit 802, a calculation unit 803, a determination unit 804, and a discharge control unit 805 as functional configurations. Some or all of the above parts may be realized by software (program) or may be realized by a hardware circuit. As one aspect, each of the above parts is a function performed by the ASIC 705. However, some functions or all functions may be executed by the CPU 701. Further, some functions or all functions may be executed by a chip (hardware) (not shown).

The acquisition unit 801 acquires image data from the host H. More specifically, the acquisition unit 801 acquires image data from the host H via the host I / F 706. For example, the acquired image data is image data for color ink or white ink.

The generation unit 802 generates print data from the image data by converting the color space of the image data acquired by the acquisition unit 801 into the color space for the image forming apparatus 1.

For example, the generation unit 802 generates image data (intermediate data) in CMYKW format by converting sRGB values of image data expressed in sRGB format into CMYKW (cyan, magenta, yellow, black, white) values. .. From the image data in the CMYKW format, the generation unit 802 defines print data (hereinafter referred to as white plate data) defining an image formed with white ink and print data defining an image formed with inks of each CMYK color (hereinafter referred to as color). Version data) and is generated. Here, the white plate data indicates the ejection amount per ejection when ejecting white ink, and the color plate data indicates the ejection amount per ejection when ejecting ink of each color of CMYK. Become.

Specifically, for the white plate data, only the W value indicated by any value from 0 to 255 is extracted from the image data in the CMYKW format for all the pixels and generated as intermediate data. .. Then, the W value (256-step gradation value) of the intermediate data is reduced to a low gradation by using an error diffusion method or the like, so that white plate data is generated. For example, the white plate data is obtained by reducing the W value of the intermediate data to a binary value indicating the presence or absence of ink ejection. In the case of printing that does not use white ink, the white plate data is null or the white plate data itself is not generated.

The calculation unit 803 calculates the ejection amount (usage amount) of the ink used at the time of image formation based on the print data or the like. In the present embodiment, the calculation unit 803 calculates the ejection amount of the white ink among the inks of each color.

For example, the calculation unit 803 calculates the ejection amount of the white ink used at the time of image formation from the number and ratio of the values indicating the presence / absence of ejection among the two values indicating the presence / absence of ejection constituting the white plate data.

The determination unit 804 determines one liquid discharge head 122w to be used for image formation from the liquid discharge heads 122w1 and 122w2 based on the discharge amount calculated by the calculation unit 803.

For example, the determination unit 804 selects the default liquid discharge head 122w1 when the discharge amount calculated by the calculation unit 803 is less than the threshold value, and selects the liquid discharge head 122w2 having a small mist generation amount when the discharge amount is equal to or more than the threshold value. do. The threshold value is set to an arbitrary value so that the liquid discharge head 122w1 is determined to be used in the solid portion or the like because the discharge amount is large, and the liquid discharge head 122w2 is determined to be used in the portion where the discharge amount is small such as drawing thin lines or characters. can do.

<Ink>
Hereinafter, the organic solvent, water, coloring material, resin, additives and the like used for the first ink and the second ink (hereinafter, may be referred to as the ink of the present invention) will be described.

<Organic solvent>
The organic solvent used in the present invention is not particularly limited, and a water-soluble organic solvent can be used. Examples thereof include ethers such as polyhydric alcohols, polyhydric alcohol alkyl ethers and polyhydric alcohol aryl ethers, nitrogen-containing heterocyclic compounds, amides, amines and sulfur-containing compounds.
Specific examples of the water-soluble organic solvent include, for example, ethylene glycol, diethylene glycol, 1,2-propanediol, 1,3-propanediol, 1,2-butanediol, 1,3-butanediol, and 1,4-butane. Dire, 2,3-butanediol, methoxymethylbutanol, 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 Polyhydric alcohols such as 4-trimethyl-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, Polyhydric alcohol alkyl ethers such as propylene glycol monoethyl ether, polyhydric alcohol aryl ethers such as ethylene glycol monophenyl ether and ethylene glycol monobenzyl ether, 2-pyrrolidone, N-methyl-2-pyrrolidone, N-hydroxyethyl Nitrogen-containing heterocyclic compounds such as -2-pyrrolidone, 1,3-dimethyl-2-imidazolidinone, ε-caprolactam, γ-butyrolactone, formamide, N-methylformamide, N, N-dimethylformamide, 3-methoxy- Amidos such as N, N-dimethylpropionamide, 3-butoxy-N, N-dimethylpropionamide, amines such as monoethanolamine, diethanolamine, triethylamine, sulfur-containing compounds such as dimethylsulfoxide, sulfolane, thiodiethanol, propylene. Examples thereof include carbonate and ethylene carbonate.
It is preferable to use an organic solvent having a boiling point of 250 ° C. or lower because it not only functions as a wetting agent but also has good drying properties.

Polyol compounds having 8 or more carbon atoms and glycol ether compounds are also preferably used. Specific examples of the polyol compound having 8 or more carbon atoms include 2-ethyl-1,3-hexanediol and 2,2,4-trimethyl-1,3-pentanediol.
Specific examples of the glycol ether compound 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; Examples thereof include polyhydric alcohol aryl ethers such as ethylene glycol monophenyl ether and ethylene glycol monobenzyl ether.

The content of the organic solvent in the ink is not particularly limited and may be appropriately selected depending on the intended purpose, but is preferably 10% by mass or more and 60% by mass or less from the viewpoint of ink drying property and ejection reliability. More preferably, it is 20% by mass or more and 60% by mass or less.

In the present invention, it is preferable that the second ink contains glycerin and the content thereof is 30 [mass%] or more. According to this form, the effect that the dynamic surface tension is kept high is achieved. A more preferable content of glycerin is 32 [mass%] or more and 45 [mass%] or less in the second ink.

<Water>
The content of water in the ink is not particularly limited and may be appropriately selected depending on the intended purpose, but from the viewpoint of ink drying property and ejection reliability, it is preferably 10% by mass or more and 90% by mass or less, and 20% by mass. % To 60% by mass is more preferable.

<Color material>
The coloring material is not particularly limited, and pigments and dyes can be used.
As the pigment, an inorganic pigment or an organic pigment can be used. These may be used alone or in combination of two or more. Further, a mixed crystal may be used.
As the pigment, for example, a black pigment, a yellow pigment, a magenta pigment, a cyan pigment, a white pigment, a green pigment, an orange pigment, a glossy color pigment such as gold or silver, a metallic pigment, or the like can be used.
As inorganic pigments, carbon black produced by known methods such as contact method, furnace method, thermal method, in addition to titanium oxide, iron oxide, calcium carbonate, barium sulfate, aluminum hydroxide, barium yellow, cadmium red, and chrome yellow. Can be used.
Examples of organic pigments include azo pigments and polycyclic pigments (for example, phthalocyanine pigments, perylene pigments, perinone pigments, anthraquinone pigments, quinacridone pigments, dioxazine pigments, indigo pigments, thioindigo pigments, isoindolinone pigments, quinophthalone pigments, etc.). , Dye chelate (for example, basic dye type chelate, acid dye type chelate, etc.), nitro pigment, nitroso pigment, aniline black and the like can be used. Among these pigments, those having a good affinity with a solvent are preferably used. In addition, resin hollow particles and inorganic hollow particles can also be used.
As a specific example of the pigment, for black, carbon black (CI pigment black 7) such as furnace black, lamp black, acetylene black, channel black, or copper, iron (CI pigment black 11) , Metals such as titanium oxide, and organic pigments such as aniline black (CI 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 Calcium 6B), 60: 1, 63: 1, 63: 2, 64: 1, 81, 83, 88, 101 (Bengara), 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 Greens 1, 4, 7, 8, 10, 17, 18, 36, etc.
The dye is not particularly limited, and acid dyes, direct dyes, reactive dyes, and basic dyes can be used, and one type may be used alone or two or more types may be used in combination.
As the dye, for example, 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. Dilekdo Black 19,38,51,71,154,168,171,195, C.I. I. Reactive Red 14, 32, 55, 79, 249, C.I. I. Reactive Black 3, 4, 35 can be mentioned.

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 viewpoint of improving the image density, good fixing property and ejection stability. It is as follows.

In the present invention, it is possible to fill the first liquid ejection head and the second liquid ejection head having different mist generation amounts with the first ink and the second ink having different pigment concentrations. By increasing the pigment concentration of the first ink as compared with the second ink, it is suitable for improving the OD of the color ink and the white hiding property of the white ink.
The difference between the pigment concentration of the first ink and the pigment concentration of the second ink is, for example, preferably 1% by mass or more, and more preferably 2% by mass or more.

In order to disperse the pigment to obtain an ink, a method of introducing a hydrophilic functional group into the pigment to obtain a self-dispersing pigment, a method of coating the surface of the pigment with a resin and dispersing it, and a method of dispersing using a dispersant are used. The method, etc. can be mentioned.
As a method of introducing a hydrophilic functional group into a pigment to obtain a self-dispersing 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) so that the pigment can be dispersed in water. Can be mentioned.
Examples of the method of coating the surface of the pigment with a resin and dispersing the pigment include a method of encapsulating the pigment in microcapsules so that the pigment can be dispersed in water. This can be rephrased as a resin-coated pigment. In this case, it is not necessary that all the pigments blended in the ink are coated with the resin, and the uncoated pigments and the partially coated pigments are dispersed in the ink as long as the effect of the present invention is 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 represented by a surfactant.
As the dispersant, for example, an anionic surfactant, a cationic surfactant, an amphoteric surfactant, a nonionic surfactant and the like can be used depending on the pigment.
RT-100 (nonionic surfactant) manufactured by Takemoto Oil & Fat Co., Ltd. and Naphthalene sulfonic acid Na formalin condensate can also be suitably used as a dispersant.
The dispersant may be used alone or in combination of two or more.

<Pigment dispersion>
It is possible to obtain an ink by mixing a material such as water or an organic solvent with a pigment. It is also possible to produce an ink by mixing a material such as water or an organic solvent with a pigment dispersion obtained by mixing a pigment and other water or a dispersant.
The pigment dispersion is obtained by mixing and dispersing water, a pigment, a pigment dispersant, and other components as necessary, and adjusting the particle size. It is good to use a disperser for dispersion.
The particle size of the pigment in the pigment dispersion is not particularly limited, but the maximum frequency is 20 nm or more in terms of the maximum number because the dispersion stability of the pigment is good and the image quality such as ejection stability and image density is also high. It is preferably 500 nm or less, and more preferably 20 nm or more and 150 nm or less. The particle size of the pigment can be measured using a particle size analyzer (Nanotrack Wave-UT151, manufactured by Microtrac Bell Co., Ltd.).
The content of the pigment in the pigment dispersion is not particularly limited and may be appropriately selected depending on the intended purpose. However, good ejection stability can be obtained and the image density is increased by 0.1 mass. % Or more and 50% by mass or less are preferable, and 0.1% by mass or more and 30% by mass or less are more preferable.
It is preferable that the pigment dispersion is degassed by filtering coarse particles with a filter, a centrifuge, or the like, if necessary.

<Resin>
The type of resin contained in the ink is not particularly limited and may be appropriately selected depending on the intended purpose. For example, urethane resin, polyester resin, acrylic resin, vinyl acetate resin, styrene resin, butadiene resin, etc. Examples thereof include resins, styrene-butadiene resins, vinyl chloride resins, acrylic styrene resins, and acrylic silicone resins.
Resin particles made of these resins may be used. It is possible to obtain ink by mixing resin particles with a material such as a coloring material or an organic solvent in the state of a resin emulsion in which water is used as a dispersion medium. As the resin particles, those synthesized as appropriate may be used, or commercially available products may be used. Further, these may be used alone or in combination of two or more kinds of resin particles.

The volume average particle size of the resin particles is not particularly limited and may be appropriately selected depending on the intended purpose. However, from the viewpoint of obtaining good fixability and high image hardness, 10 nm or more and 1,000 nm or less are preferable. More than 200 nm is more preferable, and 10 nm or more and 100 nm or less is particularly preferable.
The volume average particle size can be measured using, for example, a particle size analyzer (Nanotrack Wave-UT151, manufactured by Microtrac Bell Co., Ltd.).

The content of the resin is not particularly limited and may be appropriately selected depending on the intended purpose. However, from the viewpoint of fixability and storage stability of the ink, 1% by mass or more and 30% by mass or less with respect to 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, but from the viewpoint of improving image quality such as ejection stability and image density, the maximum frequency in terms of the maximum number of inks. Is preferably 20 nm or more and 1000 nm or less, and 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 Microtrac Bell Co., Ltd.).

<Additives>
If necessary, a surfactant, an antifoaming agent, an antiseptic / antifungal agent, a rust preventive agent, a pH adjuster and the like may be added to the ink.

<Surfactant>
As the surfactant, any of a silicone-based surfactant, a fluorine-based surfactant, an amphoteric surfactant, a nonionic surfactant, and an anionic surfactant can be used.
The silicone-based surfactant is not particularly limited and may be appropriately selected depending on the intended purpose. Among them, those that do not decompose even at high pH are preferable, and examples thereof include side chain modified polydimethylsiloxane, double-ended modified polydimethylsiloxane, single-ended modified polydimethylsiloxane, side chain double-ended modified polydimethylsiloxane, and the like. Those having an oxyethylene group and a polyoxyethylene polyoxypropylene group are particularly preferable because they exhibit good properties as an aqueous surfactant. Further, 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 Si portion side chain of dimethylsiloxane.
Examples of the fluorine-based surfactant include a perfluoroalkyl sulfonic acid compound, a perfluoroalkyl carboxylic acid compound, a perfluoroalkyl phosphate ester compound, a perfluoroalkyl ethylene oxide adduct, and a perfluoroalkyl ether group in the side chain. Polyoxyalkylene ether polymer compounds are particularly preferred because they have low foaming properties. Examples of the perfluoroalkyl sulfonic acid compound include perfluoroalkyl sulfonic acid and perfluoroalkyl sulfonic acid salt. Examples of the perfluoroalkylcarboxylic acid compound include perfluoroalkylcarboxylic acid and perfluoroalkylcarboxylic acid salt. The polyoxyalkylene ether polymer compound having a perfluoroalkyl ether group in the side chain includes a sulfate ester salt of a polyoxyalkylene ether polymer having a perfluoroalkyl ether group in the side chain and a perfluoroalkyl ether group in the side chain. Examples thereof include salts of polyoxyalkylene ether polymers. The counter ions of the salts in these fluorine-based surfactants include Li, Na, K, NH ₄ , NH ₃ CH ₂ CH ₂ OH, NH ₂ (CH ₂ CH ₂ OH) ₂ , and NH (CH ₂ CH ₂ OH). ₃ etc. can be mentioned.
Examples of the amphoteric tenside include laurylaminopropionate, lauryl dimethyl betaine, stearyl dimethyl betaine, and lauryl dihydroxyethyl betaine.
Examples of the nonionic surfactant include polyoxyethylene alkyl phenyl ether, polyoxyethylene alkyl ester, polyoxyethylene alkyl amine, polyoxyethylene alkyl amide, polyoxyethylene propylene block polymer, sorbitan fatty acid ester, and polyoxyethylene sorbitan. Examples thereof include a fatty acid ester and an ethylene oxide adduct of acetylene alcohol.
Examples of the anionic surfactant include polyoxyethylene alkyl ether acetate, dodecylbenzene sulfonate, lauryl salt, polyoxyethylene alkyl ether sulfate salt and the like.
These may be used alone or in combination of two or more.

As the fluorine-based surfactant, a compound having 2 to 16 carbon atoms substituted with fluorine is preferable, and a compound having 4 to 16 carbon atoms substituted with fluorine is more preferable.
Examples of the fluorosurfactant include a perfluoroalkyl phosphate ester compound, a perfluoroalkylethylene oxide adduct, and a polyoxyalkylene ether polymer compound having a perfluoroalkyl ether group in the side chain. Among these, the polyoxyalkylene ether polymer compound having a perfluoroalkyl ether group in the side chain is preferable because it has less foaming property, and is particularly a fluorine-based compound represented by the general formula (F-1) and the general formula (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)
CnF _{2n + 1} -CH ₂ CH (OH) CH ₂ -O- (CH ₂ CH ₂ O) a-Y
In the compound represented by the above general formula (F-2), Y is H or CmF _{2m + 1} and m is an integer of 1 to 6, or CH ₂ CH (OH) CH ₂ -CmF _{2m + 1} and m is 4 to 6. It is an integer, or C _p H _{2p + 1} , and p is an integer from 1 to 19. n is an integer of 1 to 6. a is an integer of 4 to 14.
Commercially available products may be used as the above-mentioned fluorine-based surfactant. Examples of this commercially available product 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.); Full Lard FC-93, FC-95, FC-98, FC-129, FC-135, FC-170C, FC-430, FC-431 (all manufactured by Sumitomo 3M Co., Ltd.); Megafuck F-470, F -1405, F-474 (all manufactured by Dainippon Ink and Chemicals Co., Ltd.); 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 The Chemours Company); 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 Omniova), Unidyne DSN-403N (manufactured by Daikin Industries Co., Ltd.) Among these, FS-3100, FS-34, FS- of The Chemours Co., Ltd. from the viewpoint of remarkably improving good print quality, particularly color development, permeability to paper, wettability, and leveling property. 300, FT-110, FT-250, FT-251, FT-400S, FT-150, FT-400SW manufactured by Neos Co., Ltd., Polyfox PF-151N manufactured by Omninova, and Unidyne DSN-manufactured by Daikin Industries Co., Ltd. 403N is particularly preferable.

The content of the surfactant in the ink is not particularly limited and may be appropriately selected depending on the intended purpose.

<Defoamer>
The defoaming agent is not particularly limited, and examples thereof include a silicone-based defoaming agent, a polyether-based defoaming agent, and a fatty acid ester-based defoaming agent. These may be used alone or in combination of two or more. Among these, a silicone-based defoaming agent is preferable because it has an excellent defoaming effect.

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

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

<pH adjuster>
The pH adjusting agent is not particularly limited as long as the pH can be adjusted to 7 or more, and examples thereof include amines such as diethanolamine and triethanolamine.

The physical characteristics of the ink are not particularly limited and may be appropriately selected depending on the intended purpose. For example, the viscosity, surface tension, pH and the like are preferably in the following ranges.
The viscosity of the ink at 25 ° C. is preferably 5 mPa · s or more and 30 mPa · s or less, 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, for the viscosity, for example, a rotary viscometer (RE-80L manufactured by Toki Sangyo Co., Ltd.) can be used. As the measurement conditions, it is possible to measure at 25 ° C. with a standard cone rotor (1 ° 34'× R24), a sample liquid volume of 1.2 mL, a rotation speed of 50 rpm, and 3 minutes.
The pH of the ink is preferably 7 to 12, and more preferably 8 to 11 from the viewpoint of preventing corrosion of the metal member that comes into contact with the liquid.

The recording medium is not limited to that used as a general recording medium, and wallpaper, flooring, building materials such as tiles, cloth for clothing such as T-shirts, textiles, leather and the like can be appropriately used. Further, ceramics, glass, metal, or the like can be used by adjusting the configuration of the path for transporting the recording medium.

<Recorded material>
The ink recording material of the present invention comprises an image formed by using the ink of the present invention on a recording medium.
It can be recorded by an inkjet recording device and an inkjet recording method to obtain a recorded material.

<Recording device, recording method>
The ink of the present invention can be suitably used for various recording devices by an inkjet recording method, for example, a printer, a facsimile device, a copying device, a printer / fax / copier multifunction device, a three-dimensional modeling device, and the like.
In the present invention, the recording device and the recording method are devices capable of ejecting ink, various processing liquids, and the like to a recording medium, and a method for recording using the device. The recording medium means a medium to which ink and various treatment liquids can adhere even temporarily.
This recording device can include not only a head portion for ejecting ink, but also means related to feeding, transporting, and discharging paper of a recording medium, a pretreatment device, a device called a posttreatment device, and the like. ..
The recording device and the recording method may have a heating means used in the heating step and a drying means used in the drying step. The heating means and the drying means include, for example, means for heating and drying the printed surface and the back surface of the recording medium. The heating means and the drying means are not particularly limited, but for example, a hot air heater and an infrared heater can be used. Heating and drying can be performed before printing, during printing, after printing, and the like.
Further, the recording device and the recording method are not limited to those in which significant images such as characters and figures are visualized by ink. For example, those that form patterns such as geometric patterns and those that form three-dimensional images are also included.
Further, the recording device includes both a serial type device that moves the discharge head and a line type device that does not move the discharge head, unless otherwise specified.
Further, as this recording device, it is possible to use not only a desktop type but also a wide recording device capable of printing on an A0 size recording medium, or, for example, continuous paper wound in a roll shape as a recording medium. A continuous book printer is also included.

<Pretreatment liquid>
The pretreatment liquid contains a flocculant, an organic solvent, and water, and may contain a surfactant, an antifoaming agent, a pH adjuster, an antiseptic / antifungal agent, an anticorrosive agent, and the like, if necessary.
As the organic solvent, surfactant, defoaming agent, pH adjuster, antiseptic and antifungal agent, and rust preventive, the same materials as those used for ink can be used, and other materials used for known treatment liquids can be used. ..
The type of flocculant is not particularly limited, and examples thereof include water-soluble cationic polymers, acids, and polyvalent metal salts.

<Post-treatment liquid>
The post-treatment liquid is not particularly limited as long as it is possible to form a transparent layer. The post-treatment liquid is obtained by selecting and mixing organic solvents, water, resins, surfactants, defoamers, pH adjusters, antiseptic and antifungal agents, rust preventives and the like, if 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.

An example of the recording device will be described with reference to FIGS. 9 to 10. FIG. 9 is a perspective explanatory view of the device. FIG. 10 is a perspective explanatory view of the main tank. The image forming apparatus 400 as an example of the recording apparatus is a serial type image forming apparatus. A mechanism portion 420 is provided in the exterior 401 of the image forming apparatus 400. Each ink storage section 411 of the main tank 410 (410k, 410c, 410m, 410y) for each color of black (K), cyan (C), magenta (M), and yellow (Y) is, for example, a package of an aluminum laminated film or the like. It is formed of members. The ink container 411 is housed in, for example, a plastic container case 414. As a result, the main tank 410 is used as an ink cartridge for each color.
On the other hand, a cartridge holder 404 is provided behind the opening when the cover 401c of the main body of the apparatus is opened. A main tank 410 is detachably attached to the cartridge holder 404. As a result, each ink ejection port 413 of the main tank 410 and the ejection head 434 for each color communicate with each other via the supply tube 436 for each color, and ink can be ejected from the ejection head 434 to the recording medium.

The method of using the ink is not limited to the inkjet recording method, and can be widely used. In addition to the inkjet recording method, examples thereof include a blade coating method, a gravure coating method, a bar coating method, a roll coating method, a dip coating method, a curtain coating method, a slide coating method, a die coating method, and a spray coating method.

The use of the ink of the present invention is not particularly limited and may be appropriately selected depending on the intended purpose, and can be applied to, for example, printed matter, paints, coating materials, base materials and the like. Further, it can be used not only as an ink to form two-dimensional characters and images, but also as a three-dimensional modeling material for forming a three-dimensional stereoscopic image (three-dimensional model).
As the three-dimensional modeling apparatus for modeling the three-dimensional object, a known one can be used, and is not particularly limited, but for example, an apparatus provided with ink accommodating means, supply means, ejection means, drying means and the like is used. be able to. The three-dimensional model includes a three-dimensional model obtained by overcoating with ink. Further, a molded product obtained by processing a structure in which ink is applied on a base material such as a recording medium is also included. The molded product is, for example, a sheet-shaped or film-shaped recorded material or structure that has been subjected to molding processing such as heat stretching or punching, and is, for example, an automobile, OA equipment, or electricity. -Suitably used for molding after decorating the surface of electronic devices, meters of cameras, panels of operation parts, etc.

Further, in the terms of the present invention, image formation, recording, printing, printing, etc. are all synonymous.

Recording media, media, and printed matter are all synonymous.

Hereinafter, the present invention will be described in more detail with reference to examples, but the present invention is not limited to these examples. The part indicates a mass part.

<Preparation of white pigment dispersion>
40 parts of titanium oxide (trade name: JR-405, manufactured by TAYCA Corporation), 5 parts of pigment dispersant (trade name: TEGO Dispers 651, manufactured by Ebonic), 55 parts of water are mixed, and a bead mill (trade name: Research Lab, A white pigment dispersion was obtained by dispersing 0.3 mmΦ zirconia beads at a filling rate of 60% and 8 m / s for 5 minutes at Simmal Enterprises Co., Ltd.).
The volume average particle size D50 of the white pigment dispersion was measured using Nanotrac Wave-EX1500 (manufactured by Microtrac Bell Co., Ltd.) and found to be 210 nm.

[Manufacturing of resin particle dispersion]
The resin particle dispersion liquid 1 was synthesized by the following procedure. First, in a 500 mL separable flask equipped with a stirrer, a thermometer, and a reflux tube, 74 parts of T5651 (polycarbonate diol, manufactured by Asahi Kasei Chemicals), 10 parts of dimethylol propionic acid, 50 parts of dicyclohexylmethane diisocyanate (H12MDI), And 135 parts of methyl ethyl ketone dehydrated by molecular sieve was charged, the temperature was raised to 70 ° C. under a nitrogen stream, 200 ppm of tin 2-ethylhexanoate was added, and the isocyanate concentration in the system was measured at 70 ° C. 3 The reaction was carried out for 10 hours to 10 hours. Then, the temperature in the system was lowered to 40 ° C., triethylamine was added as needed, 270 parts of ion-exchanged water was added while stirring at a speed of 300 rpm, and the mixture was stirred for 1 hour and then 2-methyl-1,5. -Three parts of pentanediamine were added and stirred for 3 to 6 hours. Then, the mixture was cooled to room temperature, the solvent was distilled off by an evaporator, and the solid content was adjusted to 30% with ion-exchanged water to obtain a resin particle dispersion liquid 1.

The resin particle dispersion liquid 2 was synthesized by the following procedure. In a 1 L four-necked flask equipped with a nitrogen introduction tube, a dehydration tube, a stirrer and a thermocouple, 1,6-hexanediol as a diol, adipic acid as a dicarboxylic acid, and a ratio of OH / COOH = 1.22. In addition, 300 ppm of titanium tetraisopropoxide was added, and the reaction was carried out while flowing out water under a nitrogen stream, and finally the temperature was raised to 230 ° C. and the reaction was carried out until the resin acid value became 5 or less. Then, the reaction was carried out at a vacuum degree of 0.6 kPa for 4 hours to obtain the first resin 1 (hydroxyl value 75). Then, first, in a 500 mL separable flask equipped with a stirrer, a thermometer, and a reflux tube, 150 parts of the first resin as a polyol, 4.5 parts of dimethylol propionic acid, 22 parts of isophorone diisocyanate, and a molecular sieve are used for dehydration. 50 parts of the treated methyl ethyl ketone was charged, the temperature was raised to 70 ° C. under a nitrogen stream, 200 ppm of tin 2-ethylhexanoate was added, and the reaction was carried out at 70 ° C. for 3 to 10 hours while measuring the isocyanate concentration in the system. I let you. Next, the temperature in the system was lowered to 40 ° C., after adding triethylamine, 150 parts of ion-exchanged water was added while stirring at a speed of 300 rpm, and after stirring for 1 hour, 2.2 parts of diethylenetriamine was added and stirred for 1 hour. did. Then, the mixture was cooled to room temperature, the solvent was distilled off by an evaporator, and the solid content was adjusted to 30% to obtain a resin particle dispersion liquid 2.

Preparation of Ink The materials were mixed according to the formulation shown in Table 1, stirred for 1 hour, and then pressure-filtered with a 1.2 μm cellulose acetate membrane filter to obtain an ink. Ion-exchanged water was added so that the total was 100 parts.

Preparation of pretreatment liquid The pretreatment liquid was obtained by mixing and stirring with the following formulation, and filtering with a 0.8 μm filter (Minisart manufactured by Sartorius).
・ Calcium chloride ・ Dihydrate: 10 parts ・ Proxel XLII (manufactured by Arch Chemicals Japan): 0.3 parts ・ Ion-exchanged water: Remaining

The materials in the table represent the following.
-PG: Polyethylene glycol-MMB: Methoxymethylbutanol-SAG503A: Silicone surfactant represented by the general formula (2) (Silface SAG503A manufactured by Nisshin Chemical Industry Co., Ltd.)

In the general formula (2), R represents a hydrogen atom or a methyl group, m1 and m2 represent an integer of 0 to 6, and n represents an integer of 2 to 20.

Next, the production of the nozzle plate to be mounted on the inkjet head will be described.
<Making Nozzle Plate A>
A fluorine-containing acrylate ester polymer solution (Optur DSX, manufactured by Daikin Industries, Ltd.) was prepared.
An ink-repellent film having an average thickness of 20 nm is applied to the surface of the nozzle substrate on the ink ejection side by a dipping method and dried. Formed.
From the above, the nozzle plate A was manufactured. At this time, the nozzle holes were masked with a water-soluble resin, and the back surface of the nozzle substrate was masked with tape to form an ink-repellent film, and then peeled off. Further, the ink-repellent film was formed by heating at 120 ° C. for 1 hour.

<Making the nozzle plate B>
A silicone resin solution (SR 2441 RESIN, manufactured by Toray Dow Corning Co., Ltd.) was prepared.
The silicone resin solution was applied to the surface of the same nozzle substrate on the ink ejection side by a dipping method and dried to form an ink-repellent film having an average thickness of 100 nm. From the above, the nozzle plate B was manufactured. At this time, the nozzle holes were masked with a water-soluble resin, and the back surface of the nozzle substrate was masked with tape to form an ink-repellent film, and then peeled off. This was heated and cured at 150 ° C. for 2 hours in the atmosphere to obtain an ink-repellent film.

As described above, the nozzle plate has an ink-repellent film, and the ink-repellent film of the nozzle plate contains fluorine and silicone, which is advantageous in terms of wiping property. In particular, the ink-repellent film containing fluorine is highly effective and enables stable ejection over a long period of time.

The nozzle plates prepared as described above were attached to the liquid discharge heads, respectively. Nozzle plate A is assembled to head 1 with a large amount of mist and head 2 with a small amount of mist, and nozzle plate B is assembled to a head 3 with a large amount of mist and a head 4 with a small amount of mist, respectively. Created the head of.

<Amount of mist>
A 20 μm-thick Pyrene film P2111 (manufactured by TOYOBO) was set on Ri6000 (manufactured by Ricoh Corporation), the inkjet printer was filled with white ink, and the adhesion amount was set to 20.0 mg / cm ² .
A 2 cm square grid pattern was printed with a line width of 0.3 pt, and further dried by a heat press set at 160 ° C. for 1 minute to obtain an evaluation image. Images were observed with a 25x loupe and the amount of mist was evaluated according to the following criteria.
[Evaluation criteria]
〇: No splattering of tiny droplets in the surroundings △: Several tiny droplets can be seen in the surroundings, but they are not visually recognizable and are at a practically acceptable level. However, it is a level that can be recognized and is not practical.

<Evaluation of print sharpness>
A 20 μm-thick Pyrene film P2111 (manufactured by TOYOBO) was set on Ri6000 (manufactured by Ricoh Corporation), the inkjet printer was filled with white ink, and the adhesion amount was set to 20.0 mg / cm ² . An image for evaluation was obtained by printing a Gothic white character chart by an inkjet method and further drying it with a heat press set at 160 ° C. for 1 minute. The readability of the characters in the obtained image was judged with the naked eye and visually evaluated according to the following criteria.
[Evaluation criteria]
◯: 5pt Gothic font is readable.
Δ: 5pt Gothic typeface is unreadable, but 6pt Gothic typeface is readable. Can withstand practicality.
X: The 6pt Gothic font is unreadable and does not endure practicality.

<White concealment>
The pretreatment liquid was spray-applied to a cotton T-shirt (black) manufactured by TOM'S at a coating amount of 20 g / A4, and then dried by a heat press set at 160 ° C. for 1 minute.
Next, a cotton T-shirt (black) manufactured by TOM'S, which had been treated with a pretreatment liquid, was set in Ri6000 (manufactured by Ricoh Co., Ltd.), the inkjet printer was filled with white ink, and the adhesion amount was set to 20.0 mg / cm ² . did. Further, the image for evaluation was obtained by drying for 1 minute with a heat press set at 160 ° C.
A solid image (3 cm × 3 cm) was printed, the color was measured using X-rite exact, and the white concealment property was calculated by the following formula.
White concealment = (OD of original fabric-OD of solid image) / OD of original fabric x 100 (%)
〔Evaluation criteria〕
A: White concealment is 93% or more
B: White concealment is 88% or more and less than 93%
C: White concealment is 85% or more and less than 88%
D: White concealment is 80% or more and less than 85%
E: White concealment is 70% or more and less than 80%. A to C are acceptable.

<Discharge stability>
In an environment of 25 ° C. and 20% RH, head cleaning was executed from the printer maintenance command, and a test chart was printed to confirm that all channels of the nozzle were in the ejection state.
Next, the heating means was set to 50 ° C., solid images were continuously printed for 1 hour, head cleaning was executed once from the maintenance command of the printer, and the test chart was printed again. The number of non-ejection channels was counted from the test chart before and after leaving, and the judgment was made according to the following criteria.
[Evaluation criteria]
◯: Number of non-discharge channels is less than 3 Δ: Number of non-discharge channels is 3 or more and less than 10 ×: Number of non-discharge channels is 10 or more 〇, Δ is acceptable.

The results are shown in Table 2.

From the results in Table 2, each example passed the mist amount, print sharpness, concealment rate, and ejection stability, but in the comparative example, all of them could not reach the passing level.

1 Image forming device 4a, 4b Discharge nozzle plate 41 Nozzle forming surface 100 Main body 111 Stage 112 Image forming part 113 Conveying structure 114 Bottom housing part 115 Conveying guide member 116 Slider part 121 Carriage 122 Liquid discharge head 125 Timing belt 200 Cassette 300 Platen member 400 Fabric 500 Heating device 502 Front door 700 Control unit 701 CPU
702 ROM
703 RAM
704 NVRAM
705 ASIC
706 Host I / F
707 I / O
708 Head drive control unit 709 Main scanning motor drive unit 710 Sub-scanning motor drive unit 711 Elevating motor drive unit 801 Acquisition unit 802 Generation unit 803 Calculation unit 804 Determination unit 805 Discharge control unit 1000 Image adder Na, Nb Nozzle row

Japanese Patent No. 5024408 Japanese Patent No. 6028913

Claims (8)

The first liquid ejection head that ejects the first ink,
With the second liquid ejection head, the amount of mist generated when the second ink of the same color as the first ink is ejected and the second ink is ejected is smaller than that of the first liquid ejection head. ,
A liquid discharge system characterized by being equipped with. The liquid ejection system according to claim 1, wherein the dynamic surface tension of the first ink is smaller than the dynamic surface tension of the second ink. The liquid ejection system according to claim 1 or 2, wherein the amount of the surfactant contained in the first ink is smaller than the amount of the surfactant contained in the second ink. The dynamic surface tension (25 ° C.) with a life time of 15 ms of the first ink is 30 [mN / m] or more and 50 [mN / m] or less.
The second ink has a life time of 15 ms, and the dynamic surface tension (25 ° C.) is 50 [mN / m] or more and less than 70 [mN / m], according to any one of claims 1 to 3. The liquid discharge system described. The amount of the surfactant of the first ink is 0.1 [mass%] or more and 1 [mass%] or less.
The liquid ejection system according to any one of claims 1 to 4, wherein the amount of the surfactant of the second ink is 0.5 [mass%] or less. The liquid ejection system according to any one of claims 1 to 5, wherein the second ink contains glycerin and the content thereof is 30 [mass%] or more. The liquid ejection system according to any one of claims 1 to 6, wherein the pigment concentration contained in the first ink is higher than the pigment concentration contained in the second ink. A claim, wherein the discharge nozzle plate provided on the surface of the first liquid discharge head and the second liquid discharge head has an ink-repellent film, and the ink-repellent film contains fluorine or silicone. The liquid discharge system according to any one of 1 to 7.

Images