Recording apparatus, recording method, and ink composition

Abstract

The present disclosure provides a recording apparatus, a recording method, and an ink composition having excellent visibility and initial filling properties of an ink liquid surface. A recording apparatus includes an ink container, an ink supply unit, an inkjet head, and an ink composition, the ink container including: an ink injection port into which the ink composition is injected; and a liquid level display unit that displays an ink level of the ink composition accommodated in the ink accommodating body, in which the inkjet head receives the supply of the ink composition from the ink accommodating body via the ink supply unit, ejects the ink composition and adheres the ink composition to a recording medium, and displays a liquid level of the ink composition accommodated in the ink accommodating body. The ink composition is an aqueous red ink containing an azo pigment, an alkynediol surfactant (A) having an HLB value of less than 10, and an alkynediol surfactant (B) having an HLB value of 10 or more.

Description

Technical Field

[0001] The present invention relates to a recording device, a recording method and an ink composition. Background Art

[0002] As described above, an inkjet recording apparatus is known that records an image or the like on a recording medium using minute ink droplets ejected from nozzles of a recording head for inkjet recording.

[0003] In addition, as remote work and SOHO increase, opportunities for using inkjet recording devices at home and the like are also increasing.

[0004] The inkjet recording apparatus includes an ink container (eg, an ink cartridge) for supplying an ink composition to a recording head.

[0005] Known examples of such ink containers include a type in which the ink container itself is replaced when the ink composition in the ink container reaches a certain amount or less (so-called ink cartridges), and a type in which the ink composition is replenished in a continuous supply type ink container without replacing the ink container (so-called continuous supply type ink container).

[0006] For example, Patent Document 1 describes an ink composition that is injected into an ink container having an ink chamber that can be replenished with the ink composition and an ink injection port that can be opened and closed, and the ink chamber can be connected to the external air, and contains a pigment, a resin, and an organic solvent, wherein the static contact angle between the ink composition and a member on the inner side of a wall that divides the ink chamber is greater than 10°.

[0007] Prior art literature

[0008] Patent Literature

[0009] Patent Document 1: Japanese Patent Application Publication No. 2015-061896.

[0010] As the ink container, for example, the above-mentioned continuous supply type ink container (also referred to as CISS tank in this specification) can be cited. CISS tank has the advantage of being able to print continuously without the trouble of replacing ink cartridges. In addition, the ink cartridge is not required for each replacement, and the ink container only needs to be replenished with ink.

[0011] However, although a CISS tank may include a liquid level indicator for checking the remaining amount of ink, the visibility of the liquid level indicator may be impaired due to ink adhering to the wall surface.

[0012] On the other hand, when the printer is filled with ink for the first time, for example, air bubbles may be mixed into the inkjet head, thereby impairing the filling performance. Summary of the invention

[0013] The present inventors have conducted intensive studies to solve the above-mentioned problems. As a result, they have found that the above-mentioned problems can be solved by using an inkjet recording device having a predetermined structure, and have completed the present invention.

[0014] The present invention is as follows.

[0015] The recording device of the present invention is a recording device comprising an ink container, an ink supply unit, an inkjet head and an ink composition.

[0016] The ink container comprises: an ink injection port, into which the ink composition is injected; and a liquid level display portion, which displays the ink liquid level of the ink composition contained in the ink container.

[0017] The inkjet head receives the ink composition from the ink container via the ink supply unit, and discharges the ink composition to attach it to a recording medium.

[0018] The ink composition is an aqueous red ink containing an azo pigment, an acetylene glycol surfactant A having an HLB value of less than 10, and an acetylene glycol surfactant B having an HLB value of 10 or more.

[0019] The recording method of the present invention is a recording method performed using a recording device having an ink container, an ink supply unit, and an inkjet head, and has:

[0020] a supplying step of supplying an ink composition from the ink container to the inkjet head via the ink supplying unit; and

[0021] an attachment step of ejecting the ink composition from the inkjet head to attach it to a recording medium,

[0022] The ink container comprises: an ink injection port, into which the ink composition is injected; and a liquid level display portion, which displays the ink liquid level of the ink composition contained in the ink container.

[0023] The ink composition is an aqueous red ink containing an azo pigment, an acetylene glycol surfactant A having an HLB value of less than 10, and an acetylene glycol surfactant B having an HLB value of 10 or more.

[0024] The ink composition of the present invention is an ink composition used for recording in a recording device having an ink container, an ink supply unit, and an inkjet head.

[0025] The ink container comprises: an ink injection port, into which the ink composition is injected; and a liquid level display portion, which displays the ink liquid level of the ink composition contained in the ink container.

[0026] The inkjet head receives the ink composition from the ink container via the ink supply unit, and discharges the ink composition to attach it to a recording medium.

[0027] The ink composition is an aqueous red ink containing an azo pigment, an acetylene glycol surfactant A having an HLB value of less than 10, and an acetylene glycol surfactant B having an HLB value of 10 or more. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 : is a table showing the results of the examples.

[0029] Figure 2 : is a table showing the results of the examples.

[0030] Figure 3 : is a table showing the results of the examples.

[0031] Figure 4 This is a schematic diagram of an example of the inkjet recording device according to this embodiment.

[0032] Figure 5 This is a schematic diagram of another example of the inkjet recording apparatus according to this embodiment.

[0033] Explanation of symbols

[0034] 1. Inkjet recording device; 12. Paper supply port; 13. Support portion; 14. Paper discharge port; 16. Slide; 17. Inkjet head; 20 (20Bk, 20Cn, 20Ma, 20Yw), auxiliary tank; 24, ink supply tube (ink supply path); 50, ink container; 54 (51), ink injection port; X, X axis; Y, Y axis; Z, Z axis. DETAILED DESCRIPTION

[0035] Hereinafter, an embodiment of the present invention (hereinafter referred to as “the present embodiment”) will be described in detail, but the present invention is not limited thereto and various modifications can be made without departing from the gist of the invention.

[0036] 1. Recording device

[0037] The recording device of this embodiment is a recording device having an ink container, an ink supply unit, an inkjet head and an ink composition, wherein the ink container has: an ink injection port, the ink injection port is used to inject the ink composition; and a liquid level display unit, the liquid level display unit displays the ink liquid level of the ink composition contained in the ink container, wherein the ink supply unit supplies the ink composition from the ink container to the inkjet head, the inkjet head receives the supply of the ink composition from the ink container via the ink supply unit, and ejects the ink composition to make it adhere to the recording medium, and the ink composition is an aqueous red ink containing an azo pigment, an acetylene glycol surfactant A with an HLB value of less than 10, and an acetylene glycol surfactant B with an HLB value of more than 10.

[0038] Inks containing quinacridone pigments have been known as red inks such as magenta inks. However, inks containing quinacridone pigments sometimes have insufficient color development and ink surface visibility. Therefore, the present inventors believe that the ink surface visibility can be improved by using a red ink containing an azo pigment (red color) having good color development.

[0039] However, it is known that red ink containing azo pigments (red ink) has good color development properties. Therefore, once the ink adheres to the inner wall surface of the liquid level indicator, it will hinder the visual recognition of the ink liquid level, making it difficult to visually recognize the liquid level.

[0040] When the ink is injected into the ink container, the ink sometimes adheres to the inner wall surface of the ink container. This is because the ink splashes or bubbles are generated when the ink is injected. In addition, due to the shaking of the ink container, the ink adheres to the inner wall surface of the liquid level display part. In addition, when the ink is consumed and the ink level is lowered, the ink adhered to the inner wall surface of the liquid level display part remains.

[0041] In these cases, if the ink has excellent flowability, the ink quickly flows down from the inner wall surface of the liquid level display portion without adhesion. However, if the ink has poor flowability, the speed of the ink flowing down from the inner wall surface of the liquid level display portion is slow, and the ink adhesion will remain.

[0042] In addition, if the speed at which the ink flows down is slow, the ink dries before it flows down and its fluidity decreases, so that the ink becomes difficult to flow down further. As a result, the visibility of the ink level in the liquid level display portion decreases.

[0043] The recording device of this embodiment has excellent visibility of the ink liquid surface and initial filling performance by including the above-mentioned configuration.

[0044] 1.1. Ink container

[0045] The recording device of this embodiment includes an ink container.

[0046] The ink container has: an ink injection port for injecting the ink composition; and a liquid level display portion for displaying the ink liquid level of the ink composition contained in the ink container.

[0047] As for the ink container in this embodiment, unless otherwise specified, the form is not limited. For example, in the ink container of each color (such as CISS tank), the height from the ink injection port to the bottom may also be different according to the design or layout of the ink container. For example, it is also possible to use an ink container with a high height from the ink injection port to the bottom. For example, in the case where the ink container is stacked in two layers in order to miniaturize the lateral length of the printer, it is also possible to set an ink container with a height equivalent to two ordinary ink containers.

[0048] Alternatively, when using an ink container with a large capacity, the lateral width of the ink container may be lengthened. From the perspective of layout, if the lateral width of the ink container is not desired to be lengthened, the height of the ink container may be increased. In this case, the height from the injection port to the bottom of the CISS tank of each color may be different.

[0049] Furthermore, CISS cans of different colors may have the same capacity but different heights in a free layout.

[0050] The ink injection port is an inlet for injecting the ink composition in order to fill the ink container with the ink composition.

[0051] The ink composition injected from the ink injection port is contained in the ink container. If the ink composition is contained in the ink container, the ink liquid level can be visually recognized from the liquid level display unit.

[0052] The liquid level display unit displays the ink liquid level of the ink composition contained in the ink container, thereby enabling confirmation of the remaining amount of the ink composition.

[0053] Since the liquid level indicator is contained in the ink container, the material of the liquid level indicator and the material of the ink container may be the same. The material of the liquid level indicator and the ink container is the material of the inner part thereof in contact with the ink.

[0054] The material of the liquid level indicator is not particularly limited, but is preferably a thermoplastic resin, preferably a polyolefin, and more preferably, the material of the inner wall surface of the liquid level indicator is polypropylene.

[0055] The liquid level indicator is not particularly limited, and may be, for example, a transparent or semi-transparent resin or glass, etc. The liquid level indicator allows the user to visually check the ink liquid level of the ink composition contained in the ink container from the outside of the ink container.

[0056] From the viewpoint of suppressing foaming and improving initial filling properties, the volume of the ink container is preferably 10 cm 3 ~500cm 3 , preferably 40cm 3 ~400cm 3 , preferably 80cm 3 ~300cm 3 .

[0057] Specifically, the ink container may be in the following aspects.

[0058] The ink container supplies the ink composition to the inkjet head via the ink supply unit. The ink container may also include an ink injection port provided at the top and a liquid container connected to the ink injection port and the outside air. The user inserts the replenishment port of the ink bottle into the ink injection port of the ink container, and can inject the ink contained in the ink bottle into the ink container. That is, the ink container is preferably a so-called continuous supply type ink container that replenishes the ink from the outside without replacing the ink container even if the ink contained in the ink container is exhausted. The problem of foaming of the ink composition often occurs, especially when the ink is added, so the inkjet recording device of this embodiment preferably has a continuous supply type ink container that can be filled with ink.

[0059] Such a continuous supply type ink container having an ink injection port for injecting the ink composition and capable of continuously supplying ink to the inkjet head is called a CISS tank.

[0060] Inkjet printers having such a continuous supply type ink container capable of refilling ink are sometimes used in offices, SOHOs, etc. to print text and images on plain paper.

[0061] 1.2.Ink supply unit

[0062] The recording device of this embodiment includes an ink supply unit.

[0063] The ink supply unit supplies the ink composition from the ink container to the inkjet head. Specifically, the ink supply unit may be, for example, an ink supply tube or an ink tube, which is a component that allows the ink to flow from the ink container to the inkjet head and supplies the ink from the ink container to the inkjet head.

[0064] The ink container and the inkjet head are connected via an ink supply unit.

[0065] When the ink is circulated, the ink may be circulated by negative pressure or a height difference generated by ejecting the ink from the inkjet head, or by using a liquid feeding mechanism such as a pump.

[0066] 1.3.Inkjet head

[0067] The recording device of this embodiment includes an inkjet head.

[0068] The inkjet head receives supply of the ink composition from the ink container via the ink supply unit, and discharges the ink composition to attach it to a recording medium.

[0069] The inkjet head may include a nozzle face provided at a position facing the recording surface of the recording medium, and may eject ink in the form of droplets from a plurality of nozzles provided on the nozzle face to adhere to the recording surface of the recording medium.

[0070] The inkjet head can be a line head or a serial head.

[0071] In the line method using a line head, the head is fixed and the recording medium is moved in the sub-scanning direction (the longitudinal direction of the recording medium, the conveying direction), and ink droplets are ejected from the nozzle opening of the head in conjunction with the movement, thereby recording an image on the recording medium. A line printer, which is a line-type inkjet recording device, has a line head as a head having a length equal to or greater than the width of the recording medium.

[0072] On the other hand, in the serial method using a serial head, the head is moved in the main scanning direction (lateral or width direction of the recording medium), and ink droplets are ejected from the nozzle opening of the head in conjunction with the movement, thereby recording an image on the recording medium. A serial printer, which is an inkjet recording device of the serial method, performs the following main scanning (stroke), and generally performs recording in two or more strokes (multi-stroke). In the main scanning, the head ejects the ink composition while moving in the main scanning direction intersecting the sub-scanning direction of the recording medium.

[0073] The inkjet head has: a cavity that ejects the contained ink composition from a nozzle; an ejection drive unit that is provided for each cavity and provides a driving force for ejecting the ink composition; and a nozzle that is provided for each cavity and ejects the ink composition to the outside of the inkjet head. The cavity, the ejection drive unit and the nozzle provided for each cavity can also be provided in multiple numbers independently of each other on one inkjet head. The ejection drive unit can be formed using an electro-mechanical conversion element such as a piezoelectric element that changes the volume of the cavity by mechanical deformation, an electron-thermal conversion element that generates bubbles in the ink by heat and ejects it, and the like.

[0074] The inkjet recording device may be provided with one head for one color of ink, or may be provided with a plurality of heads.

[0075] 1.4. Ink composition

[0076] The inkjet recording apparatus of the present embodiment includes an ink composition (also simply referred to as “ink”).

[0077] At least one of the ink compositions is an aqueous red ink containing an azo pigment, an acetylene glycol surfactant A having an HLB value of less than 10, and an acetylene glycol surfactant B having an HLB value of 10 or more.

[0078] The ink composition in this embodiment can also be designed to satisfy required characteristics based on the structure and properties of the recording device, ink container, and the like.

[0079] Hereinafter, components that may be included in the ink composition (hereinafter, also simply referred to as “ink”) in the present embodiment will be described.

[0080] 1.4.1. Azo pigments

[0081] The ink composition of this embodiment contains an azo pigment. Examples of the azo pigment include monoazo pigments, disazo pigments, condensed disazo pigments, benzimidazolone pigments, etc. Among azo pigments, a pigment capable of coloring in a red color is used.

[0082] For example, an azo pigment that can make the inkjet ink composition a red ink can be used, and an azo pigment numbered CI Pigment Red can be mentioned.

[0083] Specific examples of such azo pigments include CI Pigment Red 5, CI Pigment Red 17, CI Pigment Red 22, CI Pigment Red 31, CI Pigment Red 48:1, CI Pigment Red 48:2, CI Pigment Red 53:1, CI Pigment Red 57:1, CI Pigment Red 146, CI Pigment Red 150, CI Pigment Red 185, CI Pigment Red 114, CI Pigment Red 146, CI Pigment Red 150, CI Pigment Red 170, CI Pigment Red 184, CI Pigment Red 185, CI Pigment Red 208, CI Pigment Red 245, CI Pigment Red 268, CI Pigment Red 269, and solid solutions thereof.

[0084] Among the above, the azo pigment is preferably one or more selected from the group consisting of CI Pigment Red 150, CI Pigment Red 269, and CI Pigment Red 17 from the viewpoint of obtaining an image with more excellent color development properties.

[0085] In addition, from the viewpoint of obtaining an image with more excellent color development properties, the azo pigment is preferably a compound represented by the following formula (I) and a solid solution thereof.

[0086] [Chemical formula 1]

[0087]

[0088] (In formula (I), A represents a hydrogen atom or an aromatic group.)

[0089] Here, the aromatic group is a group having an aromatic ring such as a benzene ring or a naphthalene ring, and the aromatic ring may be substituted or unsubstituted. In addition, the aromatic ring is directly bonded to the nitrogen atom to which the aromatic group is bonded. Furthermore, when the aromatic ring has a substituent, the substituent is not particularly limited, and may be, for example, an organic group or an inorganic group, and the number of substituents may also be arbitrarily selected. The substituent is not limited, and may include, for example, an alkyl group, a halogen group, an alkoxy group, a hydroxyl group, a carboxyl group, an amino group, a nitro group, and the like.

[0090] The azo pigment may be a resin-dispersed pigment dispersed in a resin, or a self-dispersed pigment in which a functional group is introduced by treating the surface of the pigment. The resin-dispersed pigment is preferred.

[0091] The volume average particle size D50 of the azo pigment is preferably 110 nm or less. The volume average particle size D50 of the azo pigment can be measured using a particle size distribution measuring device. As a particle size distribution measuring device, for example, a particle size distribution meter based on a dynamic light scattering method (e.g., "Nanotrac series" manufactured by Microtrac BEL) can be cited. The volume average particle size is set to the D50 value.

[0092] The volume average particle size of the azo pigment is preferably 10 nm to 110 nm, more preferably 50 nm to 110 nm, further preferably 80 nm to 110 nm, further preferably 80 nm to less than 110 nm, further preferably 80 nm to 100 nm.

[0093] By setting the volume average particle size of the azo pigment in the above range, the dispersion stability of the pigment is good, the color development property is further improved, and the precipitation of the components during storage is further suppressed.

[0094] The volume average particle size of the azo pigment can be prepared, for example, by adjusting the degree of pulverization in the pulverization process of pulverizing the pigment particles, such as the pulverization intensity and pulverization time. In addition, it can also be adjusted by adjusting the intensity and time of stirring in the dispersion process of dispersing the pigment particles in the dispersion liquid. In addition, the particle size of the pigment can also be adjusted by classifying with a filter after pulverization and dispersion.

[0095] The ink composition of this embodiment can be made into an ink with excellent color development by containing the above-mentioned azo pigment. Therefore, the amount of ink attached for obtaining excellent color development can be reduced. Therefore, the ink consumption is small, and there is a tendency for the ink to be contained in the ink container for a long time. Even in such a case, by setting the volume average particle size of the azo pigment to the above range, the dispersion stability of the pigment is good and the color development is further improved, and the sedimentation of the components during storage is also further suppressed.

[0096] The content of the azo pigment is preferably 1.0% by mass to 8.0% by mass, more preferably 3.0% by mass to 7.5% by mass, and even more preferably 4.0% by mass to 7.0% by mass, based on the total amount of the ink composition.

[0097] When the content of the azo pigment is within this range, an image with further excellent color development properties can be obtained.

[0098] The ink composition may contain pigments other than the azo pigments.

[0099] The content of the azo pigment is preferably 70% by mass or more, preferably 80% by mass to 100% by mass, and preferably 90% by mass to 100% by mass, based on the total amount of the pigment.

[0100] The ink composition of this embodiment is a water-based red ink. Red ink is an ink mainly used to express red when printing is performed using multiple color inks to reproduce secondary or higher colors. For example, it is magenta ink, red ink, or inks similar to these.

[0101] The red ink is preferably a magenta ink. Here, the magenta ink generally refers to an ink used as an ink set together with a cyan ink, a yellow ink, and a black ink as needed. For example, it includes inks generally labeled as magenta inks in commercially available ink cartridges and all inks that are associated with magenta inks.

[0102] Red refers to a color whose hue angle is within a predetermined range in the L*a*b* color system standardized by CIE (International Commission on Illumination). The hue angle of red is preferably 5° to 60°, preferably 15° to 50°, and preferably 25° to 40°.

[0103] Red ink is the main ink used when printing red.

[0104] An ink that can express the red color alone is preferred.

[0105] The recording apparatus of the present embodiment may use inks other than the above-mentioned ink composition.

[0106] The recording device of this embodiment preferably further has cyan ink, yellow ink and black ink. In this case, the recording device of this embodiment preferably has an inkjet head C that ejects the cyan ink, an inkjet head Y that ejects the yellow ink and an inkjet head B that ejects the black ink.

[0107] The cyan ink, the yellow ink, and the black ink contain, as colorants, colorants having color development properties of cyan, yellow, and black, respectively.

[0108] 1.4.2. Surfactants

[0109] The ink in this embodiment contains an acetylene glycol surfactant A having an HLB value of less than 10 and an acetylene glycol surfactant B having an HLB value of 10 or more. The surfactant has the function of reducing the surface tension and improving the wettability with the recording medium. In addition, in this specification, the "HLB value" refers to the value defined by the Griffin method.

[0110] By including the acetylene glycol surfactant A, the initial filling property of the ink into the recording device is further improved. When the ink is initially filled (the first filling, filling into an empty state), if bubbles remain in the ink flow path or the parts in the nozzle, the ink composition will be poorly ejected due to the bubbles. The low HLB acetylene glycol surfactant improves the wettability of the ink to the ink flow path and the parts in the nozzle, suppresses the residual bubbles, and thus can prevent the poor ejection of the ink composition (initial filling property).

[0111] On the other hand, the wettability of the ink to the parts is improved, and when the ink adheres to the wall surface of the tank, the ink flows poorly, which may hinder the visual recognition of the liquid surface. In addition, the acetylene glycol surfactant A improves the foaming property of the ink, and foaming is easy. Therefore, foaming is easy to occur when the ink is filled into the tank, which causes the ink to overflow from the tank. In addition, the ink adheres to the wall surface of the tank due to the foam.

[0112] Therefore, in this embodiment, in addition to the acetylene glycol surfactant A, the acetylene glycol surfactant B is also used. As a result, the ink flows well from the tank wall surface, and the liquid surface visual recognition is further improved. In addition, the wettability of the ink is suppressed by the acetylene glycol surfactant B, the ink flows well, and the visual recognition is further improved. In addition, the acetylene glycol surfactant B also suppresses the foaming of the ink.

[0113] Examples of the acetylene glycol-based surfactant include an acetylene glycol-based surfactant represented by the following formula (1).

[0114] [Chemical formula 2]

[0115]

[0116] (In formula (1), R 1 , R 2 and R 3 Each independently represents an alkyl group having 1 to 6 carbon atoms, and m, n, p and q each independently represent an integer of 0 to 50.

[0117] R 1 , R 2 and R 3 There are no particular limitations, and examples thereof include methyl, ethyl, n-propyl, isopropyl, n-butyl, sec-butyl, and tert-butyl. 3 Preferred is a methyl group.

[0118] Examples of the acetylene glycol surfactant A include acetylene glycol surfactants represented by formula (1), preferably acetylene glycol surfactants wherein n+p and m+q in formula (1) are each independently 0 to 30. More preferably, n+p and m+q are each independently 15 or less, more preferably 10 or less, and even more preferably 5 or less.

[0119] Furthermore, an acetylene glycol-based surfactant in which n+p+m+q in formula (1) is 0 to 30 is preferred, 15 or less is more preferred, 10 or less is further preferred, and 5 or less is particularly preferred.

[0120] Furthermore, an acetylene glycol-based surfactant in which n, m, p, and q are each 0 in formula (1) is more preferred.

[0121] Among them, for example, polyoxyethylene (4) acetylene glycol ether, 2,5,8,11-tetramethyl-6-dodecene-5,8-diol, 2,4,7,9-tetramethyl-5-decene-4,7-diol, and 2,4,7,9-tetramethyldec-5-yn-4,7-diol are preferred. The inclusion of such a surfactant tends to further improve the initial filling property.

[0122] As the acetylene glycol-based surfactant B, an alkylene oxide adduct of acetylene glycol is preferred.

[0123] For example, an acetylene glycol surfactant in which n+p and m+q are independently 1 or more in formula (1) can be cited. Also, for example, an acetylene glycol surfactant in which n+p and m+q are independently 1 to 50 in formula (1) can be cited. More preferably, n+p and m+q are independently 6 to 30, more preferably 11 to 30, and even more preferably 16 to 30.

[0124] Alternatively, an acetylene glycol surfactant in which n+p+m+q in formula (1) is 1 to 50 is preferred, 6 to 30 is more preferred, 11 to 30 is further preferred, and 16 to 30 is particularly preferred. In formula (1), when the number of alkylene oxide additions is small, the HLB value tends to be small, and when the number of alkylene oxide additions is large, the HLB value tends to be large. Therefore, for example, in formula (1), by adjusting the number of alkylene oxide additions, the HLB value of the acetylene glycol surfactant can be adjusted.

[0125] For example, n+p and m+q in the formula (1) of the acetylene glycol surfactant A may be smaller than n+p and m+q in the formula (1) of the acetylene glycol surfactant B.

[0126] There are no particular limitations on commercially available products of the acetylene glycol-based surfactants, and examples thereof include Surfynol 104, 104E, 104H, 104A, 104BC, 104DPM, 104PA, 104PG-50, 104S, 420, 440, 465, 485, SE, SE-F, 504, 61, DF37, CT111, CT121, CT131, CT136, TG, and GA (all of the above are trade names, manufactured by Air Products and Chemicals, Inc.); Olfine B, Y, P, A, STG, SPC, E1004, E1010, PD-001, PD-002W, PD-003, PD-004, EXP.4001, EXP.4036, EXP.4051, EXP.4200, EXP.4300, AF-103, AF-104, AK-02, SK-14, AE-3 (all of the above are trade names, manufactured by Nissin Chemical Industry Co., Ltd.); Acetylenol E00, E00P, E40, E100 (all of the above are trade names, manufactured by Kawaken Fine Chemical Co., Ltd.).

[0127] The acetylene glycol surfactant A having an HLB value of less than 10 and the acetylene glycol surfactant B having an HLB value of 10 or more can be appropriately selected from the above.

[0128] As the acetylene glycol surfactant A, Surfynol 104 and Surfynol SE-F are preferred.

[0129] As the acetylene glycol surfactant B, Olfine E1010 and EXP.4200 are preferred.

[0130] The content of the acetylene glycol surfactant A is preferably 0.1% by mass to 0.8% by mass based on the total amount of the ink composition.

[0131] The content of the acetylene glycol surfactant B is preferably 0.1% by mass to 0.8% by mass based on the total amount of the ink composition.

[0132] When the content of the acetylene glycol surfactants A and B is within the above range, there is a tendency for the visibility of the ink amount and the initial filling property to be excellent.

[0133] From the above viewpoints, the content of each of the acetylene glycol surfactants A and B is more preferably 0.2% by mass to 0.75% by mass, and further preferably 0.3% by mass to 0.7% by mass, based on the total amount of the ink composition.

[0134] The ratio of the content of the acetylene glycol surfactant B to the content of the acetylene glycol surfactant A is preferably 0.1 to 10, 0.3 to 5, 0.5 to 2, or 0.8 to 1.5.

[0135] The HLB value of the acetylene glycol surfactant A is less than 10, preferably 7 or less, more preferably 6 or less, and further preferably 5 or less. The lower limit is 0 or more.

[0136] The HLB value of the acetylene glycol surfactant B is 10 or more, preferably 11-20, more preferably 12-17, and even more preferably 13-15.

[0137] 1.4.3. Resin

[0138] The ink in this embodiment may contain resins such as resin particles, fixing resin, water-soluble resin, and pigment dispersant resin.

[0139] The resin particles have a function of improving the adhesion of the ink attached to the recording medium, and the pigment dispersant resin has a function of improving the dispersibility of the above-mentioned pigment.

[0140] As the resin, any type of resin such as a resin in a dissolved state, an emulsion, or a particle state can be used. For example, when the resin is in a particle state (hereinafter, also referred to as "resin particles"), the average particle size of the resin particles based on volume (hereinafter, also referred to as "average particle size of the resin particles") is preferably 30 nm or more and 300 nm or less. More preferably, it is 50 nm or more and 200 nm or less. By making the average particle size of the resin particles within the above range, there is a tendency to improve the fixability of the ink to the recording medium or reduce the clogging of the filter and the recording head.

[0141] The average particle size of the resin particles can be measured by a particle size distribution measuring device based on the laser diffraction scattering method. For example, a particle size distribution meter based on the dynamic light scattering method (for example, "Microtrac UPA" manufactured by Nikkiso Co., Ltd.) can be used as the particle size distribution measuring device.

[0142] As the resin particles, for example, acrylic resins, fluorene resins, polyurethane resins, polyolefin resins, rosin-modified resins, terpene resins, polyester resins, polyamide resins, epoxy resins, vinyl chloride resins, vinyl chloride-vinyl acetate copolymers, ethylene-vinyl acetate resins, etc. can be used. These resin particles can be used alone or in combination of two or more.

[0143] The acrylic resin may also be a styrene acrylic resin.

[0144] As the resin particles, commercially available products may be used, and examples thereof include Superflex (registered trademark) 420 (polyurethane aqueous dispersion, manufactured by Daiichi Kogyo Seiyaku Co., Ltd.) and X-436 (styrene acrylic resin emulsion, manufactured by Seiko PMC Co., Ltd.).

[0145] Examples of the pigment dispersant resin include polyvinyl alcohols, polyacrylic acid, acrylic acid-acrylonitrile copolymers, vinyl acetate-acrylate copolymers, acrylic acid-acrylate copolymers, styrene-acrylic acid copolymers, styrene-methacrylic acid copolymers, styrene-methacrylic acid-acrylate copolymers, styrene-α-methylstyrene-acrylic acid copolymers, styrene-α-methylstyrene-acrylic acid-acrylate copolymers, styrene-maleic acid copolymers, styrene-maleic anhydride copolymers, vinylnaphthalene-acrylic acid copolymers, vinylnaphthalene-maleic acid copolymers, vinyl acetate-maleate copolymers, vinyl acetate-crotonic acid copolymers, vinyl acetate-acrylic acid copolymers, and the like, and salts thereof.

[0146] Among them, acrylic resins are preferred. Acrylic resins are a general term for polymers obtained by polymerizing at least acrylic monomers such as acrylic acid, methacrylic acid, acrylic esters, and methacrylic esters as one component. For example, resins obtained from acrylic monomers, copolymers of acrylic monomers and other monomers, etc. can be cited. For example, acrylic-vinyl resins, which are copolymers of acrylic monomers and vinyl monomers, can be cited, and for example, copolymers with vinyl monomers such as styrene can be cited. For example, styrene acrylic resins can be cited.

[0147] Among them, preferably a copolymer of a monomer having a hydrophobic functional group and a monomer having a hydrophilic functional group, a polymer composed of a monomer having both a hydrophobic functional group and a hydrophilic functional group. As the form of the copolymer, it can be used in any form of a random copolymer, a block copolymer, an alternating copolymer, or a graft copolymer.

[0148] The content of the resin based on solid content conversion is preferably less than 100 parts by mass, preferably 0.5 parts by mass to 60 parts by mass, preferably 1.0 parts by mass to 50 parts by mass, and preferably 2.0 parts by mass to 40 parts by mass, relative to 100 parts by mass of the pigment contained in the ink.

[0149] By making the content of the resin smaller than the content of the pigment, the formation of a film of the resin attached to the recording medium is less likely to be inhibited by the pigment, so there is a tendency for the adhesion of the ink to the recording medium to be improved.

[0150] The total content of the resin and the pigment is preferably 20% by mass or less in terms of solid content relative to the total mass of the ink (100% by mass). By setting the total amount to 20% by mass or less, the generation of aggregates in the ink can be reduced.

[0151] The total content of the resin and the pigment is more preferably 2 mass % to 15 mass %, 3 mass % to 15 mass %, or 3 mass % to 11 mass %.

[0152] 1.4.4. Organic solvents

[0153] The ink in this embodiment may contain an organic solvent, preferably a water-soluble organic solvent.

[0154] Examples of the organic solvent include alkanediols, polyols, glycol ethers, nitrogen-containing heterocyclic compounds, urea, urea derivatives, etc. These may be used alone or in combination of two or more.

[0155] Examples of the alkanediols include 1,2-alkanediols having 4 to 8 carbon atoms (e.g., 1,2-butanediol, 1,2-pentanediol, 1,2-hexanediol, 1,2-octanediol, etc.), 2-methyl-1,3-propanediol, 2,2-dimethyl-1,3-propanediol, 2-ethyl-1,3-hexanediol, etc.

[0156] Alkanediols have the functions of improving wettability to recording media and suppressing drying and solidification of ink on the nozzle surface of the recording head, etc. In addition, they can improve ink flowability and provide better liquid surface visibility, and are therefore preferred.

[0157] When alkanediols are contained, from the viewpoint of preventing excessive increase in wettability, the content thereof is preferably from 0.1% by mass to 20% by mass, more preferably from 0.5% by mass to 15% by mass, further preferably from 0.7% by mass to 10% by mass, and particularly preferably from 1.0% by mass to 4.0% by mass, relative to the total amount of the ink composition.

[0158] Among the above-mentioned alkanediols, 1,2-alkanediols having 5 or 6 carbon atoms are preferably used. This is because these compounds improve the permeability and wettability of the ink to the recording medium, but only slightly reduce the surface tension of the ink.

[0159] Examples of the glycol ethers include alkylene glycol monoethers and alkylene glycol diethers.

[0160] Examples of the alkylene glycol monoethers include ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monoisopropyl ether, ethylene glycol monobutyl ether, ethylene glycol monohexyl ether, ethylene glycol monophenyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol monobutyl ether, diethylene glycol monohexyl ether, triethylene glycol monomethyl ether, triethylene glycol monoethyl ether, triethylene glycol monobutyl ether, tetraethylene glycol monomethyl ether, tetraethylene glycol monoethyl ether, propylene glycol monomethyl ether, propylene glycol monoethyl ether, dipropylene glycol monomethyl ether, and dipropylene glycol monoethyl ether.

[0161] Examples of the alkylene glycol diethers include ethylene glycol dimethyl ether, ethylene glycol diethyl ether, ethylene glycol dibutyl ether, diethylene glycol dimethyl ether, diethylene glycol diethyl ether, diethylene glycol ethyl methyl ether, diethylene glycol dibutyl ether, triethylene glycol dimethyl ether, triethylene glycol diethyl ether, triethylene glycol dibutyl ether, triethylene glycol butyl methyl ether, tetraethylene glycol dimethyl ether, tetraethylene glycol diethyl ether, tetraethylene glycol dibutyl ether, propylene glycol dimethyl ether, propylene glycol diethyl ether, dipropylene glycol dimethyl ether, and dipropylene glycol diethyl ether.

[0162] Glycol ethers can be used alone or in combination of two or more. Glycol ethers can be preferably used because they improve the permeability and wettability of ink to recording media but reduce the surface tension of ink less.

[0163] When glycol ethers are contained, the content thereof can be, for example, 0.05% to 6% by mass relative to the total mass of the ink. Furthermore, in order to appropriately control wettability in consideration of the precipitation of aggregates, the content is preferably 0.2% to 4% by mass.

[0164] As polyols (excluding the above-mentioned alkanediols), for example, ethylene glycol, propylene glycol, 1,3-propylene glycol, 1,3-butanediol, 1,3-pentanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 2,3-butanediol, 3-methyl-1,3-butanediol, 2-methyl-2,4-pentanediol, 3-methyl-1,5-pentanediol, diethylene glycol, triethylene glycol, tetraethylene glycol, dipropylene glycol, trimethylolpropane, glycerol, etc. can be cited. From the viewpoint of being able to suppress the drying and solidification of the ink on the nozzle surface of the nozzle head and reduce clogging, poor ejection, etc., polyols can be preferably used. In the case of containing polyols, the content thereof can be set to, for example, 5% by mass or more relative to the total mass of the ink, and can further be set to 5% by mass or more and 30% by mass or less.

[0165] As nitrogen-containing heterocyclic compounds, for example, N-methyl-2-pyrrolidone, N-ethyl-2-pyrrolidone, N-vinyl-2-pyrrolidone, 2-pyrrolidone, N-butyl-2-pyrrolidone, 5-methyl-2-pyrrolidone, hydantoin, etc. can be cited. As urea or urea derivatives, urea, ethylene urea, tetramethyl urea, thiourea, etc. can be cited. They can be used alone or in combination of two or more. As with polyols, these substances can be preferably used from the viewpoint of being able to suppress the drying and solidification of the ink on the nozzle surface of the nozzle and reduce clogging, poor ejection, etc. When these substances are contained, their content can be set to, for example, 0.5% by mass or more and 10% by mass or less relative to the total mass of the ink, and more preferably 1% by mass or more and 5% by mass or less.

[0166] Polyols, nitrogen-containing heterocyclic compounds, urea, and urea derivatives function as moisturizers. Among the above, by using glycerol in combination with one or more selected from the group consisting of polyols (excluding glycerol among the above polyols), nitrogen-containing heterocyclic compounds, urea, and urea derivatives, both long-term water evaporation and rapid water evaporation on the wall surface of the ink chamber can be effectively suppressed. In this case, more preferred polyols are propylene glycol, dipropylene glycol, 1,3-butylene glycol, diethylene glycol, triethylene glycol, and trimethylolpropane. Among polyols, propylene glycol, dipropylene glycol, diethylene glycol, and 1,3-butylene glycol are preferred from the viewpoint of preventing precipitates. In addition, as nitrogen-containing heterocyclic compounds, pyrrolidone derivatives and hydantoin are preferred, and 2-pyrrolidone and hydantoin are more preferred. In addition, as urea derivatives, ethylene urea, tetramethyl urea, and thiourea are preferred.

[0167] In the case where the ink in the present embodiment contains any one or more selected from 1,2-alkanediol having 4 to 8 carbon atoms, 2-methyl-1,3-propanediol, 2,2-dimethyl-1,3-propanediol, 2-ethyl-1,3-hexanediol, and glycol ethers, from the viewpoint of preventing the precipitation of agglomerates, it is preferred to add a moisturizing agent which is a combination of glycerol and one or more selected from the group consisting of other polyols (except glycerol among the above-mentioned polyols), nitrogen-containing heterocyclic compounds, urea, and urea derivatives.

[0168] The total content of the organic solvent is preferably 0.1% by mass to 30% by mass, more preferably 1.0% by mass to 25% by mass, and even more preferably 5% by mass to 20% by mass, based on the total amount of the ink composition.

[0169] 1.4.5. Lactam compounds

[0170] The ink composition of the present embodiment preferably contains a lactam compound.

[0171] By containing a lactam compound, the chroma of the azo pigment can be maintained while preventing the precipitation and crystallization of impurities in the dispersion of the azo pigment. As a result, there is a tendency that the generation of foreign matter at the gas-liquid interface is excellent, and the clogging recovery property, ejection stability, and re-dissolution property are excellent.

[0172] In addition, the solubility of the acetylene glycol surfactant A in water is relatively low, and when the ink dries in the nozzle, it separates from the water, causing poor ejection. However, by containing a lactam compound, there is a tendency for the phase separation of the acetylene glycol surfactant A to be suppressed when the ink dries.

[0173] In addition, at the gas-liquid interface of the CISS tank liquid surface or in the nozzle, the pigment and other components of the ink dry and aggregate, thereby forming foreign matter, which may cause clogging. However, by making the ink contain a lactam compound, there is a tendency to suppress the aggregation of the pigment, improve the redispersibility, and suppress clogging. In particular, CISS tanks produce a gas-liquid interface on the liquid surface, so foreign matter at the gas-liquid interface becomes a problem, and therefore the present invention is particularly preferred.

[0174] In addition, if the ink attached to the wall of the tank dries and the pigment etc. condenses, it will stick to the wall, making it difficult for the ink to flow down, which also becomes a cause of poor visual visibility of the liquid surface. However, if the ink contains a lactam compound, it can suppress the difficulty of the ink to flow down, and the visual visibility of the liquid surface is better.

[0175] As the lactam compound, any lactam compound can be used without particular limitation as long as it is a lactam compound. Among the above-mentioned nitrogen-containing heterocyclic compounds, compounds that are lactam compounds can also be used as the lactam compound.

[0176] A lactam compound having a 4- to 7-membered ring is preferred, and a lactam compound having a 5- to 7-membered ring is preferred.

[0177] For example, 2-pyrrolidone, δ-lactam, 1-(2-hydroxyethyl)-2-pyrrolidone, ε-caprolactam, etc. are mentioned, and 1-(2-hydroxyethyl)-2-pyrrolidone and ε-caprolactam are preferred.

[0178] The content of the lactam compound is preferably 0.1% by mass to 7.0% by mass, more preferably 0.3% by mass to 6.0% by mass, and even more preferably 0.5% by mass to 5.5% by mass, based on the total amount of the ink composition.

[0179] When the content of the lactam compound is equal to or greater than the above lower limit, the generation of foreign matter at the gas-liquid interface tends to be excellently suppressed, and the clogging recovery property, discharge stability, re-dissolution property, and the like tend to be excellent.

[0180] By making the content of the lactam compound equal to or less than the above upper limit, the precipitation of the lactam compound can be suppressed, and there is a tendency that the clogging recovery property and the like are excellent.

[0181] 1.4.6. Water

[0182] The ink in this embodiment may also contain water. The ink in this embodiment is preferably an aqueous ink in which water is the main solvent of the ink and water is a component that evaporates and disperses when dried. The water content of the aqueous ink is preferably 40% by mass or more, more preferably 50% by mass or more relative to the total mass of the ink. In addition, 60% to 99% by mass is preferred.

[0183] Examples of water include pure water such as ion exchange water, ultrafiltration water, reverse osmosis water, and distilled water, and water from which ionic impurities have been removed as much as possible, such as ultrapure water. In addition, if water is sterilized by ultraviolet irradiation or addition of hydrogen peroxide, the growth of mold and bacteria can be prevented when the ink is stored for a long time.

[0184] 1.4.7. Others

[0185] The ink in this embodiment may contain wax particles (e.g., polyolefin wax, paraffin, etc.), zwitterionic compounds (e.g., betaine compounds, amino acids and their derivatives, etc.), sugars (e.g., glucose, mannose, fructose, ribose, xylose, arabinose, galactose, aldonic acid, sorbitol, maltose, cellobiose, lactose, sucrose, trehalose, maltotriose, reduced starch saccharide, etc.), sugar alcohols, hyaluronic acids, urea, preservatives / antifungal agents (e.g., sodium benzoate, pentachlorobenzene, etc.), for the purpose of improving its performance. phenolic acid, sodium 2-thiopyridine-1-oxide, sodium sorbate, sodium dehydroacetate, 1,2-dibenzothiazoline-3-one, etc.), pH adjusters (e.g. potassium dihydrogen phosphate, disodium hydrogen phosphate, sodium hydroxide, lithium hydroxide, potassium hydroxide, ammonia, diethanolamine, triethanolamine, triisopropanolamine, potassium carbonate, sodium carbonate, sodium bicarbonate, etc.), chelating agents (e.g. ethylenediaminetetraacetic acid and its salts (ethylenediaminetetraacetic acid dihydrogen disodium salt, etc.), defoaming agents (SN-WET980 (SanNopco Co., Ltd.) etc.), etc.

[0186] One form of the ink composition of the present embodiment is an ink composition for recording in a recording device having an ink container, an ink supply unit and an inkjet head, wherein the ink container has: an ink injection port for injecting the ink composition; and a liquid level display unit for displaying the ink liquid level of the ink composition contained in the ink container, wherein the inkjet head receives the supply of the ink composition from the ink container via the ink supply unit, and ejects the ink composition to attach it to a recording medium, and the ink composition is an aqueous red ink containing an azo pigment, an acetylene glycol surfactant A having an HLB value of less than 10, and an acetylene glycol surfactant B having an HLB value of 10 or more.

[0187] Figure 4 1 is a perspective view schematically showing an example of an inkjet recording apparatus according to the present embodiment. The inkjet recording apparatus 1 includes an ink container 50 and an ink supply tube 24 for supplying ink from the ink container to an inkjet head 17 .

[0188] The ink supply tube 24 is an ink supply unit. The ink supply unit may be any member as long as it can allow ink to flow inside and supply ink from the ink container to the inkjet head like the ink supply tube 24. It is a member constituting an ink supply path.

[0189] A sub-tank 20 may be provided at a relay position between the ink container 50 and the inkjet head 17, and the ink supplied via the ink supply tube 24 may be temporarily stored in the sub-tank 20 and supplied to the inkjet head 17. Alternatively, the sub-tank 20 may not be provided, and the ink may be directly supplied from the ink container 50 to the inkjet head 17 via the ink supply tube 24.

[0190] The inkjet head 17 ejects droplets of an ink composition (hereinafter, also simply referred to as “ink”) to record an image on a recording medium.

[0191] In addition, it has: a carriage 16 that carries the sub-tank 20 and the inkjet head 17 and can reciprocate in the X-axis direction; a paper supply port 12 that supplies the recording medium; a paper discharge port 14 that discharges the recording medium; and a support portion 13 that supports the recording medium supplied to the paper supply port 12.

[0192] The inkjet head 17 has a nozzle face (not shown) disposed at a position facing the recording surface of the recording medium, and ejects ink in the form of droplets from a plurality of nozzles (not shown) disposed on the nozzle face to adhere to the recording surface of the recording medium.

[0193] As an inkjet recording method, for example, the following methods can be used: a method in which a strong electric field is applied between the nozzle and an accelerating electrode placed in front of the nozzle, ink droplets are continuously ejected from the nozzle, and a printing information signal is provided to the polarization electrode for recording while the ink droplets are flying between the deflection electrodes; a method in which the ink droplets are ejected in accordance with the printing information signal without deflecting the ink droplets (electrostatic attraction method); a method in which a small pump is used to apply pressure to the ink, and the nozzle is mechanically vibrated using a crystal oscillator, etc., thereby forcibly ejecting the ink droplets; a method in which a piezoelectric element is used to apply pressure and a printing information signal to the ink at the same time, so that the ink droplets are ejected and recorded (piezoelectric method); a method in which the ink is heated and foamed using tiny electrodes according to the printing information signal, so that the ink droplets are ejected and recorded (thermal jet method), etc.

[0194] exist Figure 4 In the embodiment, the sub-tanks 20 include four sub-tanks 20Bk, 20Cn, 20Ma, and 20Yw for each color, as an example, corresponding to the inks of each color contained in the ink container 50. In addition, the inkjet heads 17 also include four sub-tanks 20Bk, 20Cn, 20Ma, and 20Yw for each color.

[0195] The carriage 16 carries the inkjet head 17 and the sub-tank 20, and reciprocates along the X-axis by a carriage moving mechanism (not shown) composed of a motor, a timing belt, etc. As the carriage 16 moves, the inkjet head 17 also reciprocates along the X-axis direction, so that the image in the X-axis direction on the recording medium is recorded by the inkjet head 17 ejecting the ink accompanying the movement of the carriage 16. In this embodiment, a so-called serial head type inkjet recording device is taken as an example for description, but it is not limited to this, and the ink container involved in the present invention can also be applied to a so-called line head type inkjet recording device.

[0196] The paper discharge port 14 is provided on the front surface of the inkjet recording device 1. In addition, the paper supply port 12 is provided on the back side of the inkjet recording device 1. By placing the recording medium at the paper supply port 12 and performing the recording operation, the recording medium is supplied from the paper supply port 12, and after the image is recorded inside, the printed paper is discharged from the paper discharge port 14. The recording medium can be conveyed by a paper feeding mechanism (not shown) for feeding paper in the Y-axis direction. In this way, the recording of the image in the Y-axis direction on the recording medium can be performed by the ejection of ink from the inkjet head 17 accompanying the movement of the recording medium by the paper feeding mechanism.

[0197] The inkjet recording device 1 has a control unit (not shown) for controlling the overall operation of the inkjet recording device 1. The control unit may include, for example, a CPU, a ROM, and a RAM. The control unit controls the operation of reciprocating the carriage 16, the operation of conveying the recording medium, the operation of ejecting ink from the inkjet head 17, the operation of supplying ink from the ink container 50, and the like.

[0198] The ink container 50 is Figure 4 , the entire ink container is shown, but there are a plurality of ink containers separated for each ink inside, and each ink has an ink supply tube 24 and an ink injection port 54. The ink injection port 54 is covered with a cap or the like (not shown) when ink is not injected, and the cap can be opened and closed. When the ink is injected, the cap is opened to inject the ink.

[0199] The ink container 50 may be formed into a plurality of ink containers by partitioning the inside with a wall, or the plurality of ink containers may be arranged in parallel. In this way, a plurality of ink containers for each ink are formed.

[0200] The positional relationship of the plurality of ink containers is not limited, and they may be arranged in the vertical direction (Z direction) or in the horizontal direction (X direction or Y direction). In the case of arranging in the vertical direction, the overall horizontal length of the ink container becomes smaller, and the horizontal length of the inkjet recording device becomes smaller, so that the installation area of ​​the inkjet recording device can be reduced, which is preferred.

[0201] The positional relationship of the plurality of ink injection ports 54 is not limited, and they may be arranged in the vertical direction (Z direction) or in the horizontal direction (X direction or Y direction). When the heights of the ink injection ports 54 in the vertical direction are consistent, it is easy to confirm the position of the ink injection ports during ink injection, and it is preferable to facilitate ink injection.

[0202] The ink container 50 is provided with a liquid level indicator (not shown). The liquid level indicator is provided, for example, on the front surface of the ink container 50 in the Y direction or on the left side surface in the X direction.

[0203] Figure 5This is a perspective view schematically showing the inkjet head and the surroundings of the ink container of another example of the inkjet recording device of this embodiment. Figure 4 Same as the example.

[0204] The inkjet head 102 has a nozzle surface (not shown) arranged at a position opposite to the recording surface of the recording medium, and ejects ink in the form of droplets from a plurality of nozzles (not shown) arranged on the nozzle surface, so that the ink adheres to the recording surface of the recording medium, thereby recording an image on the recording medium 101.

[0205] The carriage 103 can carry the inkjet head 102 and perform reciprocating motion in the X-axis direction (main scanning direction).

[0206] The carriage 103 is supported movably along a guide rail 105 arranged in the X direction, and is fixed to an endless belt 106 that moves in parallel with the guide rail 105. The endless belt 106 reciprocates by the driving force of the motor, whereby the carriage 103 reciprocates and scans in the X direction.

[0207] The transport roller 107 transports the recording medium 101 in the transport direction Y.

[0208] The ink container 108 and the inkjet head 102 are connected via an ink supply unit 104 through which ink flows, and ink is supplied from the ink container 108 to the inkjet head 102 via the ink supply unit 104 .

[0209] Although one ink container 108 is shown in the figure, it is sufficient to have the same number of ink containers 108 as the number of ink compositions that the inkjet recording device has. The same applies to the inkjet head 102. When there are two or more inkjet heads, the inkjet heads may be integrated or separated when viewed from the outside. The same applies to the ink container.

[0210] The ink container 108 is provided with an ink injection port 109 for injecting ink from the outside of the inkjet recording apparatus into the ink container 108. The ink injection port 109 may be provided on the upper surface 201 of the ink container 108 or the like.

[0211] When the inkjet recording device is used for the first time or when the amount of ink is reduced, ink is injected from an ink bottle or the like. The user can open the ink injection port 109 and inject ink into the ink container 108. The ink container 108 is placed in the inkjet recording device and is not replaced. A liquid level display unit 115 is formed on the side of the ink container 108, and the liquid level display unit 115 can visually identify the upper surface of the ink 110 contained in the ink container 108, that is, the liquid level.

[0212] 2. Recording Method

[0213] The recording method of the present embodiment is a recording method performed using the recording device of the present embodiment, comprising: a supply process, supplying an ink composition from the ink container via the ink supply portion to the inkjet head; and an attachment process, ejecting the ink composition from the inkjet head to attach it to a recording medium, the ink container comprising: an ink injection port for injecting the ink composition; and a liquid level display portion, which displays the ink liquid level of the ink composition contained in the ink container, the ink composition being an aqueous red ink containing an azo pigment, an acetylene glycol surfactant A having an HLB value of less than 10, and an acetylene glycol surfactant B having an HLB value of greater than 10.

[0214] The inkjet recording apparatus of the present embodiment includes an ink container for supplying an ink composition to an inkjet head.

[0215] There is no particular limitation on the method of supplying the ink composition from the ink container to the inkjet head.

[0216] For example, the inkjet head and the ink container may be connected to each other via a communication portion (ink supply portion), and the ink composition may be supplied from the ink container to the inkjet head via the communication portion.

[0217] Specifically, the following method may be adopted.

[0218] One end of the liquid supply tube is connected to the ink container, and the other end is connected to the inkjet head. The ink contained in the ink container is supplied to the inkjet head via the liquid supply tube.

[0219] The recording method of the present embodiment includes a step of discharging the ink composition from an inkjet head and causing the ink composition to adhere to a recording medium.

[0220] The inkjet method is not particularly limited, and examples thereof include a charge deflection method, a continuous method, and an on-demand method (piezoelectric method, bubble jet (registered trademark) method).

[0221] In the recording method of the present embodiment, in the attaching step, cyan ink, yellow ink, and black ink may be further ejected from other inkjet heads and attached to the recording medium.

[0222] In addition, there may be a step of injecting ink into the ink container. This step is a step of opening the cover of the ink injection port of the ink container and injecting ink into the ink container from the ink injection port to replenish the ink into the ink container. For example, ink in an ink bottle or the like may be injected into the ink injection port from the ink bottle.

[0223] When the ink injection is completed, the ink liquid level of the ink composition is displayed on the liquid level display unit, and the remaining amount of the ink composition can be checked.

[0224] 2.1. Recording medium

[0225] The material constituting the recording medium is not particularly limited, and examples thereof include resin materials such as polyurethane, polyethylene, polypropylene, polyester, polyamide, and acrylic resin, paper, glass, metal, ceramics, leather, wood, pottery, and cloth.

[0226] As the constituent material of the recording medium, various natural fibers, synthetic fibers, and semi-synthetic fibers such as fibers, silk, wool, cotton, linen, polyester, polyamide (nylon), acrylic acid, polyurethane, cellulose, cotton linter, rayon, cuprammonium fiber, and acetate, which are composed of at least one of the above, can be cited. As the recording medium, one or more of the above constituent materials can be combined and used. In addition, as the recording medium, objects with three-dimensional shapes such as sheets, spheres, and rectangular parallelepiped shapes can also be used.

[0227] Examples of the recording medium include an absorptive recording medium having ink absorptivity, a low-absorptive recording medium having low ink absorptivity, and a non-absorptive recording medium that does not absorb ink.

[0228] Examples of the absorptive recording medium include a recording medium having an ink-absorbing ink receiving layer provided on the surface, a recording medium whose substrate itself has ink absorptive properties, etc. Examples include cloth, plain paper, and paper for inkjet.

[0229] Examples of the low-absorption recording medium include coated paper provided with a coating layer having low ink absorption.

[0230] The non-absorbent recording medium is made of a non-ink-absorbing material such as glass, metal, or plastic, and includes recording media having no ink-absorbing ink receiving layer on the surface and recording media having an ink non-absorbent layer on the surface.

[0231] Example

[0232] Hereinafter, the present invention will be described in more detail using Examples and Comparative Examples. The present invention is not limited to the following Examples.

[0233] Materials of ink composition

[0234] The main materials of the ink compositions used in the following Examples and Comparative Examples are as follows.

[0235] pigment

[0236] Dispersion A Dispersion containing PR150 (azo pigment, Pigment Red 150)

[0237] Dispersion B Dispersion containing PV19 (quinacridone pigment, Pigment Violet 19)

[0238] Dispersion C Dispersion containing PR17 (azo pigment, Pigment Red 17)

[0239] Dispersion D Dispersion containing PR122 (quinacridone pigment, Pigment Red 122)

[0240] Preparation of pigment dispersion

[0241] Pure water was added to 20% by mass of each pigment and 7% by mass of a sodium hydroxide neutralized product of a styrene-acrylic acid copolymer (acid value 175 mgKOH / g, molecular weight 10,000) to make the whole 100% by mass, and stirred and mixed to obtain a mixture. The mixture was placed in a wet sand mill filled with zirconia beads with a diameter of 0.3 mm and dispersed for 6 hours. Then, the zirconia beads were removed by a separator and filtered with a cellulose acetate filter with a pore size of 3.0 μm to prepare a pigment dispersion. It should be noted that styrene-acrylic acid copolymer is a water-soluble polymer generally used as a dispersant for pigments. The volume average particle size D50 measured by a particle size distribution meter was 100 nm each.

[0242] Lactam compounds

[0243] HEP: 1-(2-hydroxyethyl)-2-pyrrolidone

[0244] ε-Caprolactam

[0245] Penetrant

[0246] 1,2-Hexanediol

[0247] Organic solvents

[0248] Gly: Glycerol

[0249] TEG: Triethylene glycol

[0250] Surfactants

[0251] Olfine E1010 (HLB: 13-14, acetylene glycol surfactant, manufactured by Nissin Chemical Industry Co., Ltd.)

[0252] OlfineEXP4200 (HLB: 10-12, acetylene glycol surfactant, manufactured by Nissin Chemical Industry Co., Ltd.)

[0253] Surfynol 104 (HLB: 4, manufactured by Air Products and Chemicals, Inc.)

[0254] Surfynol SE-F (HLB: 6, manufactured by Air Products and Chemicals, Inc.)

[0255] Resin

[0256] Superflex420 (polyurethane aqueous dispersion, manufactured by Daiichi Kogyo Seiyaku Co., Ltd.)

[0257] Alkali

[0258] TEA: triethanolamine

[0259] Preparation of ink composition

[0260] The pigment dispersion and the various materials are mixed as follows Figure 1 to Figure 3 The compositions shown in the table were mixed and stirred sufficiently to obtain the respective ink compositions. Figure 1 to Figure 3 In the table, the unit of the numerical value is mass %, and the total is 100.0 mass %. Pigment is the mass % of the pigment in the ink.

[0261] Any of these inks is a red ink that can be used as a magenta ink. Although not described below, it is an ink that can be used as a set by separately adjusting the yellow ink, black ink, and cyan ink. It should be noted that the magenta ink is also separately adjusted and used as a set, so that the ink of this embodiment can also be used as a red ink.

[0262] The following evaluations were performed on each ink composition.

[0263] evaluate

[0264] Visual visibility of ink level in tank

[0265] A modified machine of an inkjet recording device (EW-M873T manufactured by Epson Corporation) was prepared. A CISS tank was provided, and the inner wall of the liquid level display portion of the CISS tank was made of polypropylene. 150 mL of ink was injected into the main tank (CISS tank). After that, the ink in the main tank was extracted, and 75 mL of ink was injected again.

[0266] Three minutes after the ink was re-injected, the ink adhesion state, coloring state, and ink amount (liquid level height) were visually observed for the portion of the liquid level display portion corresponding to the difference between 150 mL and 75 mL of the main tank, and the visual recognizability of the ink amount was evaluated according to the evaluation criteria shown below.

[0267] "A" and "B" are set as permissible levels, and "C" and "D" are set as unpermissible levels.

[0268] Evaluation Benchmarks

[0269] A: There is no adhesion of ink and no coloring, and the height of the liquid level in the liquid level display portion can be visually recognized from a distance of 30 cm.

[0270] B: A small amount of ink adheres or the air-liquid boundary is thin, but the remaining amount of ink in the liquid level display portion can be confirmed from a distance of 30 cm.

[0271] C: The ink adhesion is small, but the liquid surface boundary is thin, and it is difficult to visually recognize the height of the liquid surface in the liquid surface display portion from a distance of 30 cm.

[0272] D: There is a lot of ink adhesion, and it is difficult to visually recognize the height of the liquid level in the liquid level display portion from a distance of 30 cm.

[0273] Defoaming time

[0274] 20 g of the ink composition was placed in a 100 g spiral tube and measured. The spiral tube was vertically swung 20 times, and the time until a bubble-free area with a diameter of 1 cm was formed when observing the liquid surface from above the spiral tube was defined as the defoaming time, which was evaluated according to the following evaluation criteria.

[0275] Evaluation Benchmarks

[0276] A: Defoaming time < 5 minutes

[0277] B: 5 minutes ≤ defoaming time < 30 minutes

[0278] C: 30 minutes ≤ defoaming time

[0279] Initial filling

[0280] The filtered and degassed ink composition was poured into a CISS tank of the above-mentioned inkjet recording device which was not used as a printer, and after waiting for the foam during the ink injection to subside, the inkjet head was initially filled.

[0281] After the initial filling, nozzle check printing was performed to visually confirm whether there was any distortion in the printed characters or any failure in ejection, and evaluation was performed according to the following evaluation criteria.

[0282] Evaluation Benchmarks

[0283] A: No distortion or non-printing

[0284] B: The printing is distorted or not ejected

[0285] The print distortion refers to the deviation of the ink landing position. The deviation of the landing position by 50% or more of the distance between adjacent nozzles at a distance of 0.5 mm from the nozzle in the ejection direction is regarded as the print distortion.

[0286] Redispersibility

[0287] When a new ink composition is added to the ink composition once dried on the nozzle surface, etc., it is checked whether it is dissolved again.

[0288] The ink composition was dropped onto a slide glass (2 μL×5 drops), and dried at 60° C. for 1 day.

[0289] The dried ink composition was put into water and allowed to stand for 3 minutes, then turned upside down 5 times. The slide glass was taken out and the ink residue on the glass and the re-solubility in water were evaluated according to the following evaluation criteria.

[0290] Evaluation Benchmarks

[0291] A: All ink droplets are dissolved again

[0292] B: Although the ink droplets have redissolved, there is a residue of the dried ink composition on the slide.

[0293] C: The ink drop does not dissolve any more and remains on the slide in a solid state.

[0294] printing

[0295] Set the ink drop mass to 12.5 ng / dot, set the basic resolution to 600×600 dpi, and adjust the dot density (adjust the number of ink drops per pixel) so that the ink adhesion in the full pattern is 5 mg / inch 2 , printed on xerox P paper (plain paper).

[0296] Color

[0297] A single-color test pattern was recorded under the above-mentioned printing conditions, and the test pattern was measured with a colorimeter (colorimeter: Xrite i1 (manufactured by Xrite Corporation)) to evaluate the OD value, and the color development property was evaluated according to the following evaluation criteria.

[0298] Evaluation Benchmarks

[0299] A: OD value ≥ 0.85

[0300] B: 0.85>OD value ≥ 0.75

[0301] C: 0.75>OD value

[0302] Ejection stability

[0303] Printing was continued for 1 hour under the above printing conditions, and after printing, it was visually confirmed whether there was any distortion or omission of printing. The ejection stability was evaluated according to the following evaluation criteria.

[0304] A: No distortion or omission of printing

[0305] B: Printing distortion or omission occurs

[0306] Phase separation in ink state

[0307] The ink composition was placed in a glass spiral tube and left at 60°C for 24 hours. After being taken out of the 60°C environment, it was visually confirmed whether the surfactant separated and floated on the ink liquid surface, and the phase separation in the ink state was evaluated according to the following evaluation criteria.

[0308] A: There is no separation of surfactant.

[0309] B: The surfactant is in a separated or floating oil state.

[0310] C: The surfactant is completely separated and in a two-layer state.

[0311] like Figure 1 to Figure 3 As shown, in the examples using the recording apparatus of the present embodiment, the visibility of the ink amount and the initial filling property were A or B, which means that the visibility of the ink amount and the initial filling property were excellent.

[0312] On the other hand, the visual recognition of the ink amount of Comparative Examples 1 and 6 to 9 not containing an azo pigment is poor. In addition, the visual recognition of the ink amount of Comparative Examples 2 and 3 not containing an acetylene glycol surfactant B having an HLB value of 10 or more is poor. In addition, Comparative Examples 4 and 5 not containing an acetylene glycol surfactant A having an HLB value of less than 10 have poor initial filling properties.

Claims

1. A recording device, characterized in that: A recording device comprising an ink container, an ink supply unit, an inkjet head and an ink composition, The ink container comprises: an ink injection port, into which the ink composition is injected; and a liquid level display portion, which displays the ink liquid level of the ink composition contained in the ink container. The inkjet head receives the ink composition from the ink container via the ink supply unit, and discharges the ink composition to attach it to a recording medium. The ink composition is an aqueous red ink containing an azo pigment, an acetylene glycol surfactant A having an HLB value of less than 10, and an acetylene glycol surfactant B having an HLB value of 10 or more.

2. The recording device according to claim 1, characterized in that The content of the acetylene glycol surfactant A is 0.1% to 0.8% by mass relative to the total amount of the ink composition. The content of the acetylene glycol surfactant B is 0.1% by mass to 0.8% by mass based on the total amount of the ink composition.

3. The recording device according to claim 1, characterized in that The content of the azo pigment is 1.0% by mass to 8.0% by mass based on the total amount of the ink composition.

4. The recording device according to claim 1, characterized in that The content of the lactam compound is 0.1% by mass to 7.0% by mass based on the total amount of the ink composition.

5. The recording device according to claim 1, characterized in that The red ink is magenta ink.

6. The recording device according to claim 1, characterized in that The ink composition contains 1,2-alkanediols having 4 to 8 carbon atoms. The content of the 1,2-alkanediols is 1.0% by mass to 4.0% by mass based on the total amount of the ink composition.

7. The recording device according to claim 1, characterized in that It also has cyan ink, yellow ink and black ink. The inkjet head C ejects the cyan ink, the inkjet head Y ejects the yellow ink, and the inkjet head B ejects the black ink.

8. The recording device according to claim 1, characterized in that The azo pigment is at least one selected from the group consisting of CI Pigment Red 150, CI Pigment Red 269, and CI Pigment Red 17.

9. A recording method, characterized in that: A recording method using a recording device having an ink container, an ink supply unit and an inkjet head. The recording method has: A supplying step of supplying an ink composition from the ink container to the inkjet head via the ink supplying unit; as well as an attachment step of ejecting the ink composition from the inkjet head to attach it to a recording medium, The ink container comprises: an ink injection port, into which the ink composition is injected; and a liquid level display portion, which displays the ink liquid level of the ink composition contained in the ink container. The ink composition is an aqueous red ink containing an azo pigment, an acetylene glycol surfactant A having an HLB value of less than 10, and an acetylene glycol surfactant B having an HLB value of 10 or more.

10. An ink composition, characterized in that: An ink composition for recording in a recording device having an ink container, an ink supply unit and an inkjet head, The ink container comprises: an ink injection port, into which the ink composition is injected; and a liquid level display portion, which displays the ink liquid level of the ink composition contained in the ink container. The inkjet head receives the ink composition from the ink container via the ink supply unit, and discharges the ink composition to attach it to a recording medium. The ink composition is an aqueous red ink containing an azo pigment, an acetylene glycol surfactant A having an HLB value of less than 10, and an acetylene glycol surfactant B having an HLB value of 10 or more.

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