JP7187789B2 - Device for ejecting liquid - Google Patents

Description

The present invention relates to an apparatus for ejecting liquid.

The inkjet recording method is a recording method in which ink droplets are ejected from very fine nozzles and deposited on a recording medium to form characters and images. This system has been widely used in recent years because it is easier to achieve full-color printing than other recording systems and has the advantage of being able to obtain high-resolution images even with an apparatus having a simple configuration.

One of the inks used in the inkjet recording system is active energy ray-curable ink. Actinic energy ray-curable inks have been supplied and used for offsets, silk screens, top coat agents, etc., but in recent years they have been used due to their merits, such as cost reduction due to the simplification of the drying process, and reduced solvent volatilization for environmental friendliness. quantity is increasing.

Recently, as an industrial application, there is an increasing number of applications in which decorative printing is applied to substrates to be processed using active energy ray-curable inks. It is required to ensure decorativeness while maintaining high elongation and high hardness, but it is difficult to satisfy all of these requirements.

As one of the methods of achieving both high stretching and high hardness, there is a method of using a material with a high glass transition temperature that is hard at low temperatures and stretches at high temperatures. By blending a monofunctional monomer, both stretchability and hardness are achieved. In addition, strength can be imparted by adding inorganic particles, and in Patent Document 2, the monomer component of the second layer is permeated into the lower layer of the ink layer of the first layer to increase the particle density in the surface layer. By doing so, we are trying to achieve both stretchability and hardness.

However, conventional inkjets have limitations on the viscosity of ink that can be ejected, making it difficult to increase the density of inorganic particles. Therefore, it is impossible to contain an inorganic particle dispersion having a larger particle size and a high concentration. This limits the decorativeness of the ink, and it is particularly difficult to produce a matte texture. In addition, since the ink contains inorganic particles having a large particle size, there is also the problem that the inorganic particles in the ink tend to settle over time, and the viscosity of the ink rises quickly, resulting in poor ejection. Even if ejection is possible, the density of the inorganic particles in the ink becomes non-uniform, resulting in uneven glossiness of the cured product.

Furthermore, the texture of the cured ink after curing can be changed by the particle size of the inorganic particles added. As a result, a matte texture cannot be obtained, or it becomes necessary to add a large amount of inorganic particles.

SUMMARY OF THE INVENTION An object of the present invention is to provide an apparatus for ejecting a liquid that can be stably ejected to obtain a cured product having a high hardness and a uniform matt feeling.

In order to solve the above-described problems, the present invention provides an apparatus for ejecting liquid having a liquid and a liquid ejection head, wherein the liquid ejection head includes individual liquid chambers communicating with nozzles from which the liquid is ejected. an inflow channel for causing the liquid to flow into the individual liquid chamber; and an outflow channel for causing the liquid to flow out from the individual liquid chamber, wherein the liquid flows through the inflow channel and the outflow flow. The active energy ray-curable composition contains fine particles having an average primary particle size of 100 nm to 200 nm and a polymerizable compound, the fine particles are silica particles, and the polymerizable The compound contains a monofunctional monomer and a polyfunctional monomer having a functional group of two or more, and the monofunctional monomer is characterized by being contained in an amount of 50% by mass or more with respect to the total amount of the polymerizable compound .

ADVANTAGE OF THE INVENTION According to this invention, the apparatus which can discharge stably and can obtain the hardened|cured material which has high hardness and a uniform matte feeling can be provided.

1 is a schematic diagram showing an example of an image forming apparatus according to the present invention; FIG. FIG. 3 is a schematic diagram showing an example of another image forming apparatus according to the present invention; FIG. 10 is a schematic diagram showing an example of still another image forming apparatus according to the present invention; 1 is an external perspective explanatory view of a liquid ejection head according to an embodiment of the present invention; FIG. It is a cross-sectional explanatory drawing of the direction orthogonal to the nozzle arrangement direction of the same head. It is a partial cross-sectional explanatory drawing of the direction parallel to the nozzle arrangement direction of the same head. FIG. 4 is an explanatory plan view of a nozzle plate of the same head; FIG. 4 is an explanatory plan view of each member constituting a channel member of the same head; FIG. 4 is an explanatory plan view of each member constituting a common liquid chamber member of the same head; 1 is a block diagram showing an example of a liquid circulation system according to the present invention; FIG. FIG. 6 is a cross-sectional view taken along the line A-A' in FIG. 5; FIG. 6 is a cross-sectional view taken along line B-B' of FIG. 5; BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is an explanatory plan view of an essential part of an example of a device for ejecting liquid according to the present invention; It is an explanatory side view of the main part of the device. FIG. 10 is an explanatory plan view of a main portion of another example of the liquid ejection unit according to the present invention;

DESCRIPTION OF THE PREFERRED EMBODIMENTS An apparatus for ejecting liquid according to the present invention will be described below with reference to the drawings. In addition, the present invention is not limited to the embodiments shown below, and can be changed within the scope of those skilled in the art, such as other embodiments, additions, modifications, deletions, etc. is also included in the scope of the present invention as long as the functions and effects of the present invention are exhibited.

As a result of intensive studies in view of the conventional problems, the present inventors found that by setting the primary particle size of the fine particles added to the liquid within a certain range, it is possible to produce a matte texture on the surface of the cured product. Found it. Further, by circulating the liquid in the head, it is possible to prevent sedimentation of fine particles in the liquid and increase in viscosity due to drying. .

The present invention is an apparatus for ejecting liquid, which includes a liquid and a liquid ejection head, wherein the liquid ejection head includes individual liquid chambers communicating with nozzles through which the liquid is ejected, and an outflow channel for causing the liquid to flow out from the individual liquid chamber, and the liquid is circulated through the inflow channel and the outflow channel. , which comprises an active energy ray-curable composition and contains fine particles having an average primary particle size of 100 nm to 200 nm.
Details will be described below.

(Active energy ray-curable composition)
The active energy ray-curable composition of the present invention preferably contains a monofunctional monomer, a polyfunctional monomer having a functional group of two or more functional groups, and a dispersion of fine particles, and if necessary other components. Contain.

<Polymerizable compound>
The polymerizable compound is a compound that undergoes a polymerization reaction by actinic energy rays (ultraviolet rays, electron beams, etc.) and cures. preferably included. Moreover, it is preferable that the monofunctional monomer is contained in an amount of 50% by mass or more based on the total amount of the polymerizable compound. In addition, it may contain a polymerizable oligomer or the like, if necessary.

By using a monofunctional monomer as the main component (50% by mass or more) of the polymerizable compound, the mesh structure of the polymer is reduced, and stretchability at a temperature equal to or higher than the glass transition temperature (Tg) can be obtained. In addition, this means that the higher the glass transition temperature of the polymer, the more difficult it is for the polymer chains to unravel, and the strength and hardness tend to be high up to a certain temperature range. It is preferable that the glass transition temperature of the polymer is high, and the monomer having a glass transition temperature of 50° C. or higher of the homopolymer is contained in an amount of 50% by mass or more and 90% by mass or less based on the total amount of the polymerizable compound. .

<<Monofunctional Monomer>>
There is no particular limitation as long as it is a monofunctional monomer, and it can be appropriately selected depending on the purpose. For example hydroxyethyl (meth)acrylamide, (meth)acryloylmorpholine, dimethylaminopropylacrylamide, isobornyl (meth)acrylate, adamantyl (meth)acrylate, 2-methyl-2-adamantyl (meth)acrylate, dicyclopentenyl (meth)acrylate , dicyclopentanyl (meth)acrylate, dicyclopentenyloxyethyl (meth)acrylate, 3,3,5-trimethylcyclohexane (meth)acrylate, t-butyl methacrylate, tetrahydrofurfuryl (meth)acrylate, cyclohexyl (meth)acrylate Acrylate, benzyl (meth)acrylate, 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 2-hydroxybutyl acrylate, isobutyl acrylate, t-butyl acrylate, phenoxyethyl acrylate, (2-methyl-2 -ethyl-1,3-dioxolan-4-yl)methyl acrylate, cyclic trimethylolpropane formal acrylate, and the like.

These may be used individually by 1 type, and may use 2 or more types together.
Among these, it is particularly preferable to contain a monomer having a high glass transition temperature of the cured product. When the monomer having a high glass transition temperature is blended into the ink component, the hardness at low temperature is increased, and stretchability is obtained at high temperature, so compatibility between stretchability and hardness is enhanced. It is preferable to include a monofunctional monomer having a glass transition temperature of 50° C. or higher, more preferably 80° C. or higher.

When only a monofunctional monomer is contained, the hardness of the polymerized product is remarkably lowered. Therefore, the hardness can be improved by containing a polyfunctional monomer having a functional group of two or more. The content of the polyfunctional monomer is preferably at a level that does not significantly impede stretchability, and although it depends on the number of functional groups and molecular weight of the polyfunctional monomer, it is 30% by mass or less, preferably 10% by mass, relative to the polymerizable compound. % or less is good.

<<Polyfunctional Monomer>>
The polyfunctional monomer is not particularly limited as long as it is a compound having two or more active energy ray-polymerizable functional groups, and can be appropriately selected depending on the purpose. For example, neopentyl glycol di(meth)acrylate , (poly)ethylene glycol di(meth)acrylate, diethylene glycol di(meth)acrylate, triethylene glycol di(meth)acrylate, tetraethylene glycol di(meth)acrylate, polypropylene glycol di(meth)acrylate, (poly)tetramethylene Glycol di(meth)acrylate, propylene oxide (PO) adduct di(meth)acrylate of bisphenol A, ethoxylated neopentyl glycol di(meth)acrylate, propoxylated neopentyl glycol di(meth)acrylate, ethylene oxide of bisphenol A (EO) adduct di(meth)acrylate, EO-modified pentaerythritol tri(meth)acrylate, PO-modified pentaerythritol tri(meth)acrylate, EO-modified pentaerythritol tetra(meth)acrylate, PO-modified pentaerythritol tetra(meth)acrylate , EO-modified dipentaerythritol tetra(meth)acrylate, PO-modified dipentaerythritol tetra(meth)acrylate, EO-modified trimethylolpropane tri(meth)acrylate, PO-modified trimethylolpropane tri(meth)acrylate, EO-modified tetramethylolmethane Tetra(meth)acrylate, PO-modified tetramethylolmethane tetra(meth)acrylate, pentaerythritol tri(meth)acrylate, pentaerythritol tetra(meth)acrylate, dipentaerythritol tetra(meth)acrylate, trimethylolpropane tri(meth)acrylate , tetramethylolmethane tetra(meth)acrylate, trimethylolethane tri(meth)acrylate, trimethylolpropane tri(meth)acrylate, bis(4-(meth)acryloxypolyethoxyphenyl)propane, diallyl phthalate, triallyl trimelli Tate, 1,6-hexanediol di(meth)acrylate, 1,9-nonanediol di(meth)acrylate, 1,3-butylene glycol di(meth)acrylate, 1,10-decanediol di(meth)acrylate, Neopentyl glycol di(meth)acryl hydroxypivalate lylate, tetramethylolmethane tri(meth)acrylate, dimethyloltricyclodecane di(meth)acrylate, modified glycerin tri(meth)acrylate, bisphenol A diglycidyl ether (meth)acrylic acid adduct, modified bisphenol A di(meth) Acrylate, caprolactone-modified dipentaerythritol hexa(meth)acrylate, dipentaerythritol hexa(meth)acrylate, pentaerythritol tri(meth)acrylate tolylene diisocyanate urethane prepolymer, pentaerythritol tri(meth)acrylate hexamethylene diisocyanate urethane prepolymer, ditrimethylolpropane tetra(meth)acrylate, pentaerythritol tri(meth)acrylate hexamethylene diisocyanate urethane prepolymer, urethane acrylate oligomer, epoxy acrylate oligomer, polyester acrylate oligomer, polyether acrylate oligomer, silicone acrylate oligomer, and the like.

These may be used individually by 1 type, and may use 2 or more types together. Among these, the number of functional groups is preferably from 2 to 6, and a bifunctional monomer is particularly preferred from the viewpoint that the stretchability is less likely to be inhibited.

Among these, it is preferable to use a urethane acrylate oligomer. A commercially available product can be used as the urethane acrylate oligomer. Examples of the commercially available products include UV-2000B, UV-2750B, UV-3000B, UV-3010B, UV-3200B, UV-3300B, UV-3700B, UV-6640B, UV-8630B manufactured by Nippon Chemical Synthesis Co., Ltd. UV-7000B, UV-7610B, UV-1700B, UV-7630B, UV-6300B, UV-6640B, UV-7550B, UV-7600B, UV-7605B, UV-7610B, UV-7630B, UV-7640B, UV- ７６５０Ｂ、ＵＴ－５４４９、ＵＴ－５４５４；巴工業社製のＣＮ９２９、ＣＮ９６１Ｅ７５、ＣＮ９６１Ｈ８１、ＣＮ９６２、ＣＮ９６３、ＣＮ９６３Ａ８０、ＣＮ９６３Ｂ８０、ＣＮ９６３Ｅ７５、ＣＮ９６３Ｅ８０、ＣＮ９６３Ｊ８５、ＣＮ９６５、ＣＮ９６５Ａ８０、ＣＮ９６６Ａ８０、ＣＮ９６６Ｈ９０、ＣＮ９６６Ｊ７５、ＣＮ９６８、ＣＮ９８１、ＣＮ９８１Ａ７５ 、ＣＮ９８１Ｂ８８、ＣＮ９８２、ＣＮ９８２Ａ７５、ＣＮ９８２Ｂ８８、ＣＮ９８２Ｅ７５、ＣＮ９８３、ＣＮ９８５Ｂ８８、ＣＮ９００１、ＣＮ９００２、ＣＮ９７８８、ＣＮ９７０Ａ６０、ＣＮ９７０Ｅ６０、ＣＮ９７１、ＣＮ９７１Ａ８０、ＣＮ９７２、ＣＮ９７３Ａ８０、ＣＮ９７３Ｈ８５、ＣＮ９７３Ｊ７５、ＣＮ９７５、ＣＮ９７７Ｃ７０、ＣＮ９７８、ＣＮ９７８２、ＣＮ９７８３、ＣＮ９９６、ＣＮ９８９３ ；ダイセル・サイテック社製のＥＢＥＣＲＹＬ２１０、ＥＢＥＣＲＹＬ２２０、ＥＢＥＣＲＹＬ２３０、ＥＢＥＣＲＹＬ２７０、ＫＲＭ８２００、ＥＢＥＣＲＹＬ５１２９、ＥＢＥＣＲＹＬ８２１０、ＥＢＥＣＲＹＬ８３０１、ＥＢＥＣＲＹＬ８８０４、ＥＢＥＣＲＹＬ８８０７、ＥＢＥＣＲＹＬ９２６０、ＫＲＭ７７３５、ＫＲＭ８２９６、ＫＲＭ８４５２、ＥＢＥＣＲＹＬ４８５８、ＥＢＥＣＲＹＬ８４０２、ＥＢＥＣＲＹＬ９２７０、ＥＢＥＣＲＹＬ８３１１、ＥＢＥＣＲＹＬ８７０１などが挙げられる。

As the content of the polyfunctional monomer increases, the hardness increases, but the stretchability tends to decrease. The larger the value of molecular weight/number of functional groups, the smaller the content and the smaller the effect. In addition, the higher the molecular weight, the higher the ink viscosity tends to be. A weight average molecular weight of 15,000 or less is preferable.

Here, the weight average molecular weight is the weight average molecular weight in terms of standard polystyrene molecular weight. Shodex GPC KF-806L (exclusion limit molecular weight: 2×10 ⁷ , separation range: 100 to 2×10 ⁷ , number of theoretical plates: 10,000 plates/line, filler material: styrene-divinylbenzene copolymer, filler granules diameter: 10 μm).

The content of the polyfunctional monomer is preferably 2% by mass or more and 30% by mass or less, more preferably 2% by mass or more and 20% by mass or less, and still more preferably 10% by mass or more and 20% by mass or less with respect to the total amount of the polymerizable compound. . When the content is 30% by mass or less, the stretchability can be improved, and a significant increase in ink viscosity can be prevented.
Moreover, it is preferable that the content of the inkjet ink is 20% by mass or less.

<<Other monofunctional monomers>>
Other monomers may be included as the polymerizable compound, for example, monofunctional monomers whose homopolymer has a glass transition temperature of less than 50°C may be included.
Such monofunctional monomers can be appropriately selected depending on the intended purpose. Hydroxypropyl (meth)acrylate, 2-hydroxybutyl acrylate, isobutyl acrylate, t-butyl acrylate, phenoxyethyl acrylate, (2-methyl-2-ethyl-1,3-dioxolan-4-yl)methyl acrylate, cyclic trimethylol propane formal acrylate and the like. These may be used individually by 1 type, and may use 2 or more types together.

Although the glass transition temperature is not particularly limited, it is preferably less than 50°C, more preferably 20°C or less.

<Fine particles>
In the present invention, the liquid contains fine particles having an average primary particle size of 100-200 nm. The fine particles are not particularly limited, but silica particles are preferable from the viewpoint of cost and ease of surface treatment.

Further, the type of silica particles is not particularly limited, but from the viewpoint of viscosity, a silica dispersion obtained by wet synthesis, organic surface treatment, and solvent substitution with an organic dispersion medium is preferable. From the viewpoint of cost, a silica dispersion obtained by mill-dispersing silica powder while adding a surface treatment agent or a dispersing agent is also preferable.

Conventionally, it has been difficult to eject a high-concentration fine particle dispersion by inkjet because fine particles settle in the ink flow path, and extreme thickening and hardening due to drying occur. In contrast, the present invention enables stable ejection by circulating the liquid as described above.

In the present invention, by including fine particles having an average primary particle diameter of 100 to 200 nm in the liquid, it is possible to impart appropriate hardness to the cured liquid. Further, by setting the average primary particle size to 100 to 200 nm, it is possible to impart an appropriate matte texture to the cured product. If the average primary particle size is less than 100 nm, sufficient matte texture cannot be obtained. may become.

<Curing means>
Examples of means for curing the curable composition (active energy ray-curable composition) of the present invention include heat curing and curing by active energy rays, and among these, curing by active energy rays is preferable.
Examples of the active energy ray used for curing the active energy ray-curable composition of the present invention include ultraviolet rays, electron beams, α rays, β rays, γ rays, X rays, and other polymerizable components in the composition. It is not particularly limited as long as it can impart the energy necessary for proceeding with the polymerization reaction. Especially when using a high-energy light source, the polymerization reaction can proceed without using a polymerization initiator. Further, in the case of ultraviolet irradiation, there is a strong desire to eliminate mercury from the viewpoint of environmental protection, and replacement with GaN-based semiconductor ultraviolet light emitting devices is very useful both industrially and environmentally. Furthermore, ultraviolet light emitting diodes (UV-LEDs) and ultraviolet laser diodes (UV-LDs) are compact, have a long life, are highly efficient, and are low in cost, and are preferred as ultraviolet light sources.

<Polymerization initiator>
The active energy ray-curable composition of the present invention may contain a polymerization initiator. Any polymerization initiator may be used as long as it can generate active species such as radicals and cations by the energy of active energy rays to initiate polymerization of polymerizable compounds (monomers and oligomers). As such polymerization initiators, known radical polymerization initiators, cationic polymerization initiators, base generators and the like can be used singly or in combination of two or more. Among them, radical polymerization initiators are used. is preferred. Also, in order to obtain a sufficient curing speed, the polymerization initiator is preferably contained in an amount of 5 to 20% by mass with respect to the total mass (100% by mass) of the composition.
Examples of radical polymerization initiators include aromatic ketones, acylphosphine oxide compounds, aromatic onium salt compounds, organic peroxides, thio compounds (thioxanthone compounds, thiophenyl group-containing compounds, etc.), hexaarylbiimidazole compounds, Examples include ketoxime ester compounds, borate compounds, azinium compounds, metallocene compounds, active ester compounds, compounds having a carbon-halogen bond, and alkylamine compounds.
Moreover, in addition to the polymerization initiator, a polymerization accelerator (sensitizer) can be used in combination. Examples of the polymerization accelerator include, but are not limited to, trimethylamine, methyldimethanolamine, triethanolamine, p-diethylaminoacetophenone, ethyl p-dimethylaminobenzoate, 2-ethylhexyl p-dimethylaminobenzoate, N, Amine compounds such as N-dimethylbenzylamine and 4,4'-bis(diethylamino)benzophenone are preferred, and the content thereof may be appropriately set according to the polymerization initiator to be used and its amount.

<Color material>
The active energy ray-curable composition of the present invention may contain a coloring material. As the coloring material, various pigments and dyes that impart black, white, magenta, cyan, yellow, green, orange, lustrous colors such as gold and silver, etc., depending on the purpose and required properties of the composition in the present invention. can be used. The content of the coloring material may be appropriately determined in consideration of the desired color density, dispersibility in the composition, etc., and is not particularly limited. It is preferably 1 to 20% by mass. In addition, the active energy ray-curable composition of the present invention may be colorless and transparent without containing a coloring material, and in that case, it is suitable as an overcoat layer for protecting images, for example.
As the pigment, an inorganic pigment or an organic pigment can be used, and one kind may be used alone, or two or more kinds may be used in combination.
Examples of inorganic pigments that can be used include carbon black (CI Pigment Black 7) such as furnace black, lamp black, acetylene black, and channel black, iron oxide, and titanium oxide.
Examples of organic pigments include azo pigments such as insoluble azo pigments, condensed azo pigments, azo lakes, and chelate azo pigments, phthalocyanine pigments, perylene and perinone pigments, anthraquinone pigments, quinacridone pigments, dioxane pigments, thioindigo pigments, isoindolinone pigments, and quinophthalone. Polycyclic pigments such as pigments, dye chelates (for example, basic dye chelates, acid dye chelates, etc.), dyeing lakes (basic dye lakes, acid dye lakes), nitro pigments, nitroso pigments, aniline black, Daylight fluorescent pigments may be mentioned.
In addition, a dispersant may be further included in order to improve the dispersibility of the pigment. The dispersant is not particularly limited, but includes, for example, dispersants commonly used for preparing pigment dispersions such as polymeric dispersants.
As dyes, for example, acid dyes, direct dyes, reactive dyes, and basic dyes can be used, and they may be used singly or in combination of two or more.

<Organic solvent>
Although the active energy ray-curable composition of the present invention may contain an organic solvent, it is preferable not to contain it if possible. If the composition does not contain organic solvents, especially volatile organic solvents (VOC (Volatile Organic Compounds) free), the safety of the place where the composition is handled is further increased, and it is possible to prevent environmental pollution. . The term "organic solvent" means general non-reactive organic solvents such as ether, ketone, xylene, ethyl acetate, cyclohexanone, and toluene, and should be distinguished from reactive monomers. be. In addition, "not including" an organic solvent means not including substantially an organic solvent, and it is preferably less than 0.1% by mass.

<Other ingredients>
The active energy ray-curable composition of the present invention may optionally contain other known components. Other components are not particularly limited, but include, for example, conventionally known surfactants, polymerization inhibitors, leveling agents, antifoaming agents, fluorescent whitening agents, penetration accelerators, humectants (moisturizing agents), and fixing agents. agents, viscosity stabilizers, antifungal agents, preservatives, antioxidants, ultraviolet absorbers, chelating agents, pH adjusters, and thickeners.

<Preparation of active energy ray-curable composition>
As described above, the active energy ray-curable composition of the present embodiment contains fine particles and a polymerizable compound, and the fine particles have an average primary particle size of 100 to 200 nm. Moreover, the polymerizable compound preferably contains a monofunctional monomer in an amount of 50% by mass or more relative to the total amount of the polymerizable compound, and a polyfunctional monomer having a functional group of two or more functional groups.

The active energy ray-curable composition of the present embodiment can be produced using the various components described above, and the preparation means and conditions are not particularly limited. , kitty mill, disk mill, pin mill, dyno mill, etc., and dispersed to prepare an inorganic particle or pigment dispersion, and the inorganic particle or pigment dispersion is further added with a polymerizable compound, an initiator, and a polymerization inhibitor. , a surfactant, and the like.

<Viscosity>
The viscosity of the active energy ray-curable composition of the present embodiment may be appropriately adjusted according to the application and means of application, and is not particularly limited. For example, when applying a discharge means for discharging the composition from a nozzle, the viscosity at 20° C. to 65° C., desirably at 25° C., is preferably 3 to 40 mPa·s, preferably 5 to 30 mPa·s. s is more preferred, and 6 to 15 mPa·s is particularly preferred. Moreover, it is particularly preferable that the viscosity range is satisfied without including the organic solvent.

The above viscosity was measured using a cone-plate rotary viscometer VISCOMETER TVE-22L manufactured by Toki Sangyo Co., Ltd., using a cone rotor (1°34′×R24), rotating at 50 rpm, and setting the temperature of the constant temperature circulating water to 20° C. Measurement can be performed by appropriately setting the temperature within the range of 65°C. VISCOMATE VM-150III can be used to adjust the temperature of the circulating water.

<Application>
The application of the active energy ray-curable composition of the present invention is not particularly limited as long as it is a field where active energy ray-curable materials are generally used, and can be appropriately selected according to the purpose. Examples include resins, paints, adhesives, insulating materials, release agents, coating materials, sealing materials, various resists, and various optical materials.
Furthermore, the active energy ray-curable composition of the present invention can be used not only as an ink to form two-dimensional characters and images, and to form a design coating film on various substrates, but also to form three-dimensional images (three-dimensional objects). It can also be used as a three-dimensional modeling material for forming. This three-dimensional modeling material may be used, for example, as a binder between powder particles used in a powder lamination method in which three-dimensional modeling is performed by repeating curing and lamination of powder layers. It may be used as a three-dimensional configuration material (model material) or a support member (support material) used in such a layered manufacturing method (stereolithography method). In addition, FIG. 2 shows a method of discharging the active energy ray-curable composition of the present invention to a predetermined region, irradiating the active energy ray and curing it, and sequentially laminating the solidified product to form a three-dimensional shape (details will be described later). 3, a storage pool (receiving portion) 1 of the active energy ray-curable composition 5 of the present invention is irradiated with an active energy ray 4 to form a cured layer 6 having a predetermined shape on a movable stage 3, and this is This is a method for three-dimensional modeling by successively layering layers.
As a stereolithography apparatus for molding a three-dimensional object using the active energy ray-curable composition of the present invention, a known apparatus can be used, and is not particularly limited. For example, means for containing the composition , a supply means, a discharge means, an active energy ray irradiation means, and the like.
The present invention also includes a molded article obtained by processing a cured product obtained by curing an active energy ray-curable composition and a structure in which the cured product is formed on a substrate. The molded article is, for example, a sheet-shaped or film-shaped cured product or structure subjected to molding such as heat stretching or punching.・It is suitable for applications that require molding after surface decoration, such as electronic equipment, meters for cameras, and operation panels.
The base material is not particularly limited and can be appropriately selected according to the purpose. Examples include paper, thread, fiber, fabric, leather, metal, plastic, glass, wood, ceramics, composite materials thereof, and the like. and a plastic substrate is preferable from the viewpoint of workability.

<Composition storage container>
The composition storage container of the present invention means a container in which the active energy ray-curable composition is stored, and is suitable for the above uses. For example, when the active energy ray-curable composition of the present invention is used as an ink, the container containing the ink can be used as an ink cartridge or an ink bottle. In the work, it is no longer necessary to touch the ink directly, and it is possible to prevent stains on fingers and clothes. In addition, it is possible to prevent foreign matter such as dust from entering the ink. The shape, size, material, etc. of the container itself are not particularly limited as long as they are suitable for the application and usage. should be covered with a protective sheet or the like.

<Image Forming Method and Forming Apparatus>
In the image forming method of the present invention, an active energy ray may be used, or heating may be used. In order to cure the curable composition of the present invention with an active energy ray, there is an irradiation step of irradiating the active energy ray, and the image forming apparatus of the present invention includes irradiation means for irradiating the active energy ray. , and an accommodating portion for accommodating the active energy ray-curable composition of the present invention, and the container may be accommodated in the accommodating portion. Furthermore, it may have a discharge step and discharge means for discharging the active energy ray-curable composition. The method of discharging is not particularly limited, but examples include a continuous injection type, an on-demand type, and the like. The on-demand type includes a piezo system, a thermal system, an electrostatic system, and the like.
FIG. 1 shows an example of an image forming apparatus equipped with an inkjet ejection means. Ink is ejected onto the recording medium 22 supplied from the supply roll 21 by the respective color printing units 23a, 23b, 23c, and 23d, which are provided with ink cartridges and ejection heads for active energy ray-curable inks of yellow, magenta, cyan, and black. be done. After that, the light sources 24a, 24b, 24c, and 24d for curing the ink are irradiated with active energy rays to cure the ink, thereby forming a color image. After that, the recording medium 22 is conveyed to the processing unit 25 and the print take-up roll 26 . A heating mechanism may be provided in each of the printing units 23a, 23b, 23c, and 23d so that the ink is liquefied at the ink discharge section. Further, if necessary, a mechanism may be provided for cooling the recording medium to about room temperature by contact or non-contact. Inkjet recording methods include a serial method in which a head is moved to eject ink onto a recording medium that moves intermittently according to the width of an ejection head, and a serial method in which ink is ejected onto a recording medium by moving the recording medium continuously. Any line system in which ink is ejected onto a recording medium from a head held at a fixed position can be applied.
The recording medium 22 is not particularly limited, but includes paper, film, ceramics, glass, metal, composite materials thereof, and the like, and may be in the form of a sheet. Further, the configuration may be such that only single-sided printing is possible, or that double-sided printing is also possible. Not limited to those used as general recording media, corrugated cardboard, building materials such as wallpaper and flooring, concrete, cloth for clothing such as T-shirts, textiles, leather, and the like can be used as appropriate.
Furthermore, the active energy ray irradiation from the light sources 24a, 24b, and 24c may be weakened or omitted, and after printing a plurality of colors, the active energy ray may be irradiated from the light source 24d. Thereby, energy saving and cost reduction can be achieved.
The recorded matter to be recorded with the ink of the present invention includes not only those printed on smooth surfaces such as ordinary paper and resin films, but also those printed on uneven surfaces to be printed, and those printed on metals, ceramics, and the like. It also includes those printed on a printing surface made of various materials. In addition, by layering two-dimensional images, it is possible to form an image (an image consisting of two-dimensional and three-dimensional images) or a three-dimensional object with a partial three-dimensional effect.
FIG. 2 is a schematic diagram showing an example of another image forming apparatus (three-dimensional stereoscopic image forming apparatus) according to the present invention. The image forming apparatus 39 in FIG. 2 uses a head unit (movable in the AB direction) in which inkjet heads are arranged, and ejects the first active energy ray-curable composition from the ejection head unit 30 for a modeled object. A second active energy ray-curable composition having a composition different from that of the first active energy ray-curable composition is ejected from the head units 31 and 32, and these compositions are cured by adjacent ultraviolet irradiation means 33 and 34. It is laminated while doing so. More specifically, for example, the second active energy ray-curable composition is ejected from the support ejection head units 31 and 32 onto the shaped object support substrate 37, and is irradiated with an active energy ray to be solidified. After forming the first support layer having a reservoir, the first active energy ray-curable composition is discharged from the discharge head unit 30 for a modeled object into the reservoir, and is irradiated with an active energy ray to be solidified. By repeating the step of forming the first model layer by pressing the support layer and the model layer a plurality of times while lowering the vertically movable stage 38 according to the number of layers, the support layer and the model layer are laminated to form the three-dimensional model 35 . to manufacture. After that, the support laminate 36 is removed as needed. In FIG. 2, only one ejection head unit 30 for a modeled object is provided, but two or more may be provided.

(One Embodiment of Apparatus for Ejecting Liquid)
As a result of intensive studies by the present inventors, the liquid containing the active energy ray-curable composition described above (ink as an example) is ejected using a liquid ejecting apparatus having a circulation mechanism described later. It has been found that a uniform cured product can be obtained.
BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.

An example of a liquid ejection head according to an embodiment of the present invention will be described with reference to FIGS. 4 to 9. FIG. 4 is an explanatory perspective view of the appearance of the liquid ejection head, FIG. 5 is an explanatory cross-sectional view of the head in a direction orthogonal to the nozzle array direction, and FIG. 6 is a cross-sectional view of the head in a direction parallel to the nozzle array direction. 7 is an explanatory plan view of a nozzle plate of the same head, FIG. 8 is an explanatory plan view of each member constituting a flow path member of the same head, and FIG. 9 is an explanatory plan view of each member constituting a common liquid chamber member of the same head. is.

This liquid ejection head has a nozzle plate 1, a channel plate 2, and a vibration plate member 3 as a wall member which are laminated and joined together. A piezoelectric actuator 11 for displacing the vibration plate member 3, a common liquid chamber member 20, and a cover 29 are provided.

The nozzle plate 1 has a plurality of nozzles 4 for ejecting liquid.
The channel plate 2 forms an individual liquid chamber 6 communicating with the nozzle 4 , a fluid resistance section 7 communicating with the individual liquid chamber 6 , and a liquid introduction section 8 communicating with the fluid resistance section 7 . Further, the channel plate 2 is formed by laminating and joining a plurality of plate-like members 41 to 45 from the nozzle plate 1 side, and laminating and joining these plate-like members 41 to 45 and the diaphragm member 3 to form the channel. A member 40 is constructed.
The diaphragm member 3 has a filter portion 9 as an opening that communicates with the liquid introducing portion 8 and the common liquid chamber 10 formed by the common liquid chamber member 20 .

The vibration plate member 3 is a wall member that forms the walls of the individual liquid chambers 6 of the channel plate 2 . The vibration plate member 3 has a two-layer structure (not limited to this), and is formed of a first layer forming a thin portion from the flow path plate 2 side and a second layer forming a thick portion. A deformable vibration region 30 is formed in a portion corresponding to the chamber 6 .

A plurality of nozzles 4 are arranged in a zigzag pattern on the nozzle plate 1, as shown in FIG.

As shown in FIG. 8A, the plate-like member 41 constituting the flow path plate 2 includes a through groove portion (meaning a groove-shaped through hole) 6a constituting the individual liquid chamber 6, a fluid resistance portion 51, Through grooves 51a and 52a forming the circulation flow path 52 are formed.

Similarly, as shown in FIG. 8B, the plate member 42 is formed with a through groove portion 6b forming the individual liquid chamber 6 and a through groove portion 52b forming the circulation flow path 52. As shown in FIG.

Similarly, as shown in FIG. 8(c), the plate member 43 is formed with through grooves 6c that form the individual liquid chambers 6 and through grooves 53a that form the circulation flow path 53 and have the nozzle arrangement direction as the longitudinal direction. It is

Similarly, as shown in FIG. 8(d), the plate member 44 includes a through groove portion 6d forming the individual liquid chamber 6, a through groove portion 7a forming the fluid resistance portion 7, and a through groove portion 8a forming the liquid introduction portion 8. , and a through groove portion 53b whose longitudinal direction is the direction in which the nozzles constituting the circulation flow path 53 are arranged is formed.

Similarly, as shown in FIG. 8(e), the plate member 45 has a through groove portion 6e that constitutes the individual liquid chamber 6, and a through groove portion 8b (filter and a through groove portion 53c having a longitudinal direction in the direction of arrangement of the nozzles forming the circulation flow path 53 is formed.

As shown in FIG. 8( f ), the vibration plate member 3 is formed with a vibration region 30 , a filter portion 9 , and a through groove portion 53 d whose longitudinal direction is the nozzle arrangement direction that constitutes the circulation flow path 53 . .

In this way, by forming the channel member by laminating and joining a plurality of plate-like members, it is possible to form a complicated channel with a simple configuration.

With the above configuration, the flow path member 40 composed of the flow path plate 2 and the vibration plate member 3 includes the fluid resistance portion 51 along the surface direction of the flow path plate 2 communicating with the individual liquid chambers 6 , the circulation flow path 52 and the circulation flow path 52 . A circulation flow path 53 is formed in the thickness direction of the flow path member 40 to communicate with the flow path 52 . The circulation flow path 53 communicates with a circulation common liquid chamber 50, which will be described later.

On the other hand, the common liquid chamber member 20 is formed with a common liquid chamber 10 to which the liquid is supplied from the supply/circulation mechanism 494 and a circulation common liquid chamber 50 .

As shown in FIG. 9(a), the first common liquid chamber member 21 constituting the common liquid chamber member 20 has a piezoelectric actuator through hole 25a, a through groove portion 10a serving as the downstream common liquid chamber 10A, a circulation A groove portion 50a having a bottom which becomes the common liquid chamber 50 is formed.

Similarly, as shown in FIG. 9B, the second common liquid chamber member 22 is formed with a piezoelectric actuator through-hole 25b and a groove portion 10b that serves as the upstream common liquid chamber 10B.

Also referring to FIG. 4 , the second common liquid chamber member 22 is formed with a through hole 71 a serving as a supply port that communicates with one end of the common liquid chamber 10 in the nozzle arrangement direction and the supply port 71 .
Similarly, in the first common liquid chamber member 21 and the second common liquid chamber member 22, the other end of the circulation common liquid chamber 50 in the nozzle arrangement direction (the end opposite to the through hole 71a) and the circulation port 81 are provided. Communicating through holes 81a and 81b are formed.
In FIG. 9, grooves with bottoms are shown with surface coating applied (the same applies to the following figures).

Thus, the common liquid chamber member 20 is composed of the first common liquid chamber member 21 and the second common liquid chamber member 22, and the first common liquid chamber member 21 is joined to the diaphragm member 3 side of the channel member 40. Then, the second common liquid chamber member 22 is layered and joined to the first common liquid chamber member 21 .

Here, the first common liquid chamber member 21 forms a downstream common liquid chamber 10A, which is a part of the common liquid chamber 10 communicating with the liquid introducing portion 8, and a circulation common liquid chamber 50 communicating with the circulation flow path 53. ing. Further, the second common liquid chamber member 22 forms an upstream common liquid chamber 10B, which is the remainder of the common liquid chamber 10. As shown in FIG.

At this time, the downstream common liquid chamber 10A, which is a part of the common liquid chamber 10, and the circulation common liquid chamber 50 are arranged side by side in a direction orthogonal to the nozzle arrangement direction, and the circulation common liquid chamber 50 placed at a position that is projected into the

As a result, the dimensions of the circulation common liquid chamber 50 are not restricted by the dimensions necessary for the flow path including the individual liquid chambers 6 formed by the flow path member 40, the fluid resistance section 7, and the liquid introduction section 8. FIG.
The circulating common liquid chamber 50 and a part of the common liquid chamber 10 are arranged side by side, and the circulating common liquid chamber 50 is arranged at a position projected into the common liquid chamber 10, so that it is perpendicular to the nozzle arrangement direction. The width of the head in the direction can be suppressed, and the enlargement of the head can be suppressed. The common liquid chamber member 20 forms a common liquid chamber 10 to which liquid is supplied from a head tank or a liquid cartridge, and a circulating common liquid chamber 50 .

On the other hand, on the opposite side of the diaphragm member 3 to the individual liquid chambers 6, a piezoelectric actuator 11 including an electromechanical conversion element is arranged as driving means for deforming the vibration region 30 of the diaphragm member 3. As shown in FIG.
As shown in FIG. 6, this piezoelectric actuator 11 has a piezoelectric member 12 bonded onto a base member 13. The piezoelectric member 12 is grooved by half-cut dicing to form a required number of piezoelectric members 12 per piezoelectric member 12, as shown in FIG. columnar piezoelectric elements 12A and 12B are formed in a comb shape at predetermined intervals.

Here, the piezoelectric element 12A of the piezoelectric member 12 is used as a piezoelectric element to be driven by applying a driving waveform, and the piezoelectric element 12B is used as a mere post without applying a driving waveform. It can also be used as a piezoelectric element that allows
The piezoelectric element 12A is joined to a convex portion 30a, which is an island-shaped thick portion formed in the vibration region 30 of the diaphragm member 3. As shown in FIG. Also, the piezoelectric element 12B is joined to the convex portion 30b, which is the thick portion of the diaphragm member 3. As shown in FIG.

The piezoelectric member 12 is formed by alternately laminating piezoelectric layers and internal electrodes. The internal electrodes are drawn out to the end faces to provide external electrodes, and flexible wiring members 15 are connected to the external electrodes.

In the liquid ejection head configured as described above, for example, by lowering the voltage applied to the piezoelectric element 12A from the reference potential, the piezoelectric element 12A contracts, the vibration area 30 of the vibration plate member 3 descends, and the volume of the individual liquid chamber 6 increases. expands, the liquid flows into the individual liquid chamber 6 .

After that, the voltage applied to the piezoelectric element 12A is increased to extend the piezoelectric element 12A in the stacking direction, deform the vibration region 30 of the diaphragm member 3 in the direction toward the nozzle 4, and contract the volume of the individual liquid chamber 6. As a result, the liquid in the individual liquid chamber 6 is pressurized, and the liquid is discharged from the nozzle 4 .

Then, liquid is drawn from the common liquid chamber 10 by surface tension and filled with liquid. Ultimately, the meniscus surface is stabilized by the balance between the negative pressure defined by the supply tank, the circulation tank, and the water head difference, and the surface tension of the meniscus, so that the next ejection operation can be performed.

The method of driving the head is not limited to the above example (pull-push-hit), and it is also possible to perform pull-hit or push-hit depending on which drive waveform is applied. Further, in the above-described embodiment, the laminated piezoelectric element is used as the pressure generating means for applying pressure fluctuations to the individual liquid chambers 6, but the present invention is not limited to this, and it is also possible to use a thin-film piezoelectric element. . Furthermore, a heating resistor may be arranged in the individual liquid chamber 6 to generate air bubbles by generating heat from the heating resistor to generate pressure fluctuations, or a pressure fluctuation may be generated by using electrostatic force. .

Next, an example of a liquid circulation system using the liquid ejection head according to this embodiment will be described with reference to FIG.
FIG. 10 is a block diagram showing the liquid circulation system according to this embodiment. As shown in FIG. 10, the liquid circulation system of this embodiment includes a main tank, a liquid discharge head, a supply tank, a circulation tank, a compressor, a vacuum pump, a liquid transfer pump, a regulator (R), a supply side pressure sensor, a circulation side It is composed of a pressure sensor and the like, and is further composed of a circulation speed control section for adjusting the overall ink circulation speed.

The supply-side pressure sensor is connected between the supply tank and the liquid ejection head and on the side of the supply channel connected to the supply port 71 (see FIG. 4) of the liquid ejection head. The circulation-side pressure sensor is connected between the liquid ejection head and the circulation tank and on the side of the circulation flow path connected to the circulation port 81 (see FIG. 4) of the liquid ejection head.
In addition, in this embodiment, although it has the structure which has a supply side pressure sensor and a circulation side pressure sensor, it is not restricted to this, It is preferable to have at least one.

One of the circulation tanks is connected to the supply tank via the first liquid-sending pump, and the other of the circulation tanks is connected to the main tank via the second liquid-sending pump. As a result, the liquid flows from the supply tank through the supply port 71 into the liquid discharge head, is discharged from the circulation port 81, and is discharged to the circulation tank. The liquid circulates by being sent.

A compressor is connected to the supply tank, and is controlled so that a predetermined positive pressure is detected by the supply side pressure sensor. On the other hand, a vacuum pump is connected to the circulation tank and controlled so that a predetermined negative pressure is detected by the circulation side pressure sensor. As a result, the negative pressure of the meniscus can be kept constant while circulating the liquid through the inside of the liquid ejection head.

In addition, when droplets are ejected from the nozzles of the liquid ejection head, the amount of liquid in the supply tank and the circulation tank decreases. should be supplemented. The timing of liquid replenishment from the main tank to the circulation tank depends on the detection result of the liquid level sensor installed in the circulation tank, such as refilling the liquid when the ink level in the circulation tank drops below a predetermined level. can be controlled.

Next, circulation of liquid in the liquid ejection head will be described. As shown in FIG. 4, at the end of the common liquid chamber member 20, a supply port 71 communicating with the common liquid chamber and a circulation port 81 communicating with the circulation common liquid chamber 50 are formed. The supply port 71 and the circulation port 81 are connected to supply tanks and circulation tanks (see FIG. 10) that store liquid through tubes, respectively. The liquid stored in the supply tank is supplied to the individual liquid chamber 6 via the supply port 71 , common liquid chamber 10 , liquid introduction portion 8 , and fluid resistance portion 7 .

Further, while the liquid in the individual liquid chamber 6 is ejected from the nozzle 4 by driving the piezoelectric element 12, part or all of the liquid remaining in the individual liquid chamber 6 without being ejected flows into the fluid resistance portion 51 and the circulation. It is circulated to the circulation tank via the flow paths 52 and 53, the circulation common liquid chamber 50, and the circulation port 81.

The liquid circulation described above is illustrated in FIGS. 11 and 12. FIG. FIG. 11 is a diagram schematically showing a cross-sectional view taken along line A-A' in FIG. 5, and arrows schematically show the flow of the liquid supplied to the supply liquid chamber 10 through the supply port 71. As shown in FIG. FIG. 12 is a diagram schematically showing a cross-sectional view taken along the line BB' of FIG. shown in

In addition, FIG. 12 shows a configuration having a fine drive mechanism, and the fine drive mechanism applies a fine pulse to nozzles that are not ejecting, so that ink thickened due to drying near the nozzles and ink behind it This mechanism is designed to circulate the ink minutely and maintain stable ejection.

In the present embodiment, the inflow channel for causing the liquid to flow into the individual liquid chamber 6 is composed of the supply port 71, the common liquid chamber 10, the fluid resistance section 7, etc., but is not limited to this and may be changed as appropriate. It is possible. Also, the outflow channel for causing the liquid to flow out from the individual liquid chamber 6 consists of the fluid resistance portion 51, the circulation channel 52, the circulation channel 53, the circulation common liquid chamber 50, the circulation port 81, etc., but is limited to this. It is possible to change it as appropriate.

The circulation of the liquid can be performed not only when the liquid ejection head is in operation, but also when it is not in operation. By circulating the liquid when the operation is paused, the liquid in the individual liquid chamber is always refreshed and the aggregation and sedimentation of the components contained in the liquid can be suppressed, which is preferable.

Furthermore, as in this case, when the ink contains fine particles that tend to settle, if the circulation speed of the ink is slow, the fine particles may settle or adhere in the circulation path. Then, the resistance in the circulation path increases, so the detection values of the supply-side pressure sensor and/or the circulation-side pressure sensor become smaller. In that case, the settling portion can be eliminated by controlling the circulation speed of the ink to be increased.

Specifically, when the detection value of the supply side pressure sensor and/or the circulation side pressure sensor drops to a preset lower limit target value (for example, less than half of the normal pressure), the preset pressure Control the flow rate so that the pressure rises to the target pressure (normal pressure) at the rate of change. In this example the flow rate is increased. This increased flow rate is maintained for a predetermined time after the detected value reaches the target pressure. Thereby, a sedimentation part can be eliminated.

Next, an example of an apparatus for ejecting liquid according to the present invention will be described with reference to FIGS. 13 and 14. FIG. FIG. 13 is an explanatory plan view of the essential parts of the device, and FIG. 14 is an explanatory side view of the essential parts of the same device.

This apparatus is a serial type apparatus, and a main scanning movement mechanism 493 reciprocates the carriage 403 in the main scanning direction. The main scanning movement mechanism 493 includes a guide member 401, a main scanning motor 405, a timing belt 408, and the like. The guide member 401 is bridged between the left and right side plates 491A and 491B to movably hold the carriage 403 . A main scanning motor 405 reciprocates the carriage 403 in the main scanning direction via a timing belt 408 stretched between a drive pulley 406 and a driven pulley 407 .

The carriage 403 is equipped with a liquid ejection unit 440 having a liquid ejection head 404 according to the present invention. The liquid ejection head 404 of the liquid ejection unit 440 ejects yellow (Y), cyan (C), magenta (M), and black (K) liquids, for example. Further, the liquid ejection head 404 is mounted with a nozzle row having a plurality of nozzles arranged in a sub-scanning direction perpendicular to the main scanning direction, and the ejection direction facing downward.

The liquid is supplied and circulated inside the liquid ejection head 404 by a supply/circulation mechanism 494 for supplying the liquid stored outside the liquid ejection head 404 to the liquid ejection head 404 . In this example, the supply/circulation mechanism 494 is composed of a supply tank, a circulation tank, a compressor, a vacuum pump, a liquid transfer pump, a regulator (R), and the like. Also, the supply-side pressure sensor is connected to the supply channel side connected to the supply pipe port 71 of the liquid ejection head, between the supply tank and the liquid ejection head. The circulation-side pressure sensor is connected between the liquid ejection head and the circulation tank and on the circulation flow path side connected to the circulation port 81 of the liquid ejection head.

This device has a transport mechanism 495 for transporting the paper 410 . The transport mechanism 495 includes a transport belt 412 as transport means and a sub-scanning motor 416 for driving the transport belt 412 .

The transport belt 412 attracts the paper 410 and transports it at a position facing the liquid ejection head 404 . The conveying belt 412 is an endless belt and stretched between a conveying roller 413 and a tension roller 414 . Adsorption can be performed by electrostatic adsorption, air suction, or the like.

The conveying belt 412 rotates in the sub-scanning direction when the conveying roller 413 is rotationally driven by the sub-scanning motor 416 via the timing belt 417 and the timing pulley 418 .

Further, on one side of the carriage 403 in the main scanning direction, a maintenance/recovery mechanism 420 for maintaining/recovering the liquid ejection head 404 is arranged on the side of the transport belt 412 .

The maintenance/recovery mechanism 420 includes, for example, a cap member 421 that caps the nozzle surface (surface on which nozzles are formed) of the liquid ejection head 404, a wiper member 422 that wipes the nozzle surface, and the like.

The main scanning movement mechanism 493, supply/circulation mechanism 494, maintenance/recovery mechanism 420, and transport mechanism 495 are attached to a housing including side plates 491A and 491B and a back plate 491C.
In this apparatus configured as described above, the paper 410 is fed onto the conveying belt 412 and attracted thereto, and the conveying belt 412 is rotated to convey the paper 410 in the sub-scanning direction.

Therefore, by driving the liquid ejection head 404 according to the image signal while moving the carriage 403 in the main scanning direction, the liquid is ejected onto the stationary paper 410 to form an image.

As described above, since this apparatus includes the liquid ejection head according to the present invention, it is possible to stably form a high-quality image.

Next, another example of the liquid ejection unit according to the invention will be described with reference to FIG. FIG. 15 is an explanatory plan view of the main part of the same unit.
Among the members constituting the apparatus for ejecting the liquid, the liquid ejection unit includes a housing portion composed of side plates 491A and 491B and a back plate 491C, a main scanning movement mechanism 493, a carriage 403, a liquid It is composed of an ejection head 404 .

A liquid ejection unit can also be constructed in which at least one of the above-described maintenance/recovery mechanism 420 and supply/circulation mechanism 494 is further attached to, for example, the side plate 491B of the liquid ejection unit. Among them, it is preferable to have a circulation mechanism.

In the present application, a "liquid ejection head" is a functional component that ejects and ejects liquid from nozzles.
The liquid to be ejected is not particularly limited as long as it has a viscosity and surface tension that can be ejected from the head. is preferred. More specifically, solvents such as water and organic solvents, colorants such as dyes and pigments, functional-imparting materials such as polymerizable compounds, resins, and surfactants, biocompatible materials such as DNA, amino acids, proteins, and calcium. , edible materials such as natural pigments, solutions, suspensions, emulsions, etc. These are, for example, inkjet inks, surface treatment liquids, components of electronic elements and light emitting elements, and formation of electronic circuit resist patterns It can be used for applications such as liquids for liquids and material liquids for three-dimensional modeling.

Piezoelectric actuators (laminated piezoelectric element and thin film piezoelectric element), thermal actuators that use electrothermal conversion elements such as heating resistors, and electrostatic actuators that consist of a diaphragm and a counter electrode are used as energy sources for liquid ejection. includes those that

A "liquid ejection unit" is a combination of functional parts and mechanisms integrated with a liquid ejection head, and is a collection of parts related to ejection of liquid. For example, the "liquid ejection unit" includes a liquid ejection head combined with at least one of the supply/circulation mechanism, carriage, maintenance/recovery mechanism, and main scanning movement mechanism.

Here, integration means, for example, that the liquid ejection head and functional parts or mechanisms are fixed to each other by fastening, adhesion, or engagement, or that one is held movably with respect to the other. include. Also, the liquid ejection head, the functional parts, and the mechanism may be configured to be detachable from each other.

For example, there is a liquid ejection unit in which a liquid ejection head and a supply/circulation mechanism are integrated. Also, there is a type in which the liquid ejection head and the supply/circulation mechanism are integrated by being connected to each other by a tube or the like. Here, a unit including a filter can be added between the supply/circulation mechanism of these liquid ejection units and the liquid ejection head.
Further, there is a liquid ejection unit in which a liquid ejection head and a carriage are integrated.

Further, as a liquid ejection unit, there is one in which the liquid ejection head is movably held by a guide member constituting a part of the scanning movement mechanism, and the liquid ejection head and the scanning movement mechanism are integrated.

There is also a liquid ejection unit in which the liquid ejection head, the carriage, and the maintenance and recovery mechanism are integrated by fixing a cap member, which is a part of the maintenance and recovery mechanism, to a carriage to which the liquid ejection head is attached. .

Further, as a liquid ejection unit, there is one in which a tube is connected to a liquid ejection head to which a supply/circulation mechanism or a channel component is attached, and the liquid ejection head and the supply mechanism are integrated. The liquid in the liquid storage source is supplied to the liquid ejection head through this tube.

It is assumed that the main scanning movement mechanism also includes a single guide member. Also, the supply mechanism includes a single tube and a single loading unit.

In the present application, a "device that ejects liquid" is a device that includes a liquid ejection head or a liquid ejection unit, drives the liquid ejection head, and ejects liquid. Devices that eject liquid include not only devices that can eject liquid onto an object to which liquid can adhere, but also devices that eject liquid into air or liquid.

The "liquid ejecting device" can include means for feeding, transporting, and ejecting an object to which liquid can adhere, as well as a pre-processing device, a post-processing device, and the like.

For example, as a "device that ejects liquid", an image forming device that ejects ink to form an image on paper, and a layer of powder to form a three-dimensional object (three-dimensional object) There is a three-dimensional modeling apparatus (three-dimensional modeling apparatus) that ejects a modeling liquid onto a formed powder layer.

Further, the "apparatus for ejecting liquid" is not limited to one that visualizes significant images such as letters and figures with the ejected liquid. For example, it includes those that form patterns that have no meaning per se, and those that form three-dimensional images.

The above-mentioned "substance to which a liquid can adhere" means a substance to which a liquid can adhere at least temporarily, such as a substance to which a liquid adheres and adheres, a substance which adheres and permeates, and the like. Specific examples include media such as recording media such as paper, recording paper, recording paper, film, and cloth, electronic components such as electronic substrates and piezoelectric elements, powder layers (powder layers), organ models, and test cells. Yes, and unless otherwise specified, includes anything that has liquid on it.

The material of the above-mentioned "thing to which a liquid can adhere" may be paper, thread, fiber, fabric, leather, metal, plastic, glass, wood, ceramics, etc., as long as the liquid can adhere even temporarily.
Further, the "liquid" is not particularly limited as long as it has a viscosity and surface tension that can be ejected from the head, but it should have a viscosity of 30 mPa·s or less at room temperature and pressure, or by heating or cooling. Preferably. More specifically, solvents such as water and organic solvents, colorants such as dyes and pigments, functional-imparting materials such as polymerizable compounds, resins, and surfactants, biocompatible materials such as DNA, amino acids, proteins, and calcium. , edible materials such as natural pigments, solutions, suspensions, emulsions, etc. These are, for example, inkjet inks, surface treatment liquids, components of electronic elements and light emitting elements, and formation of electronic circuit resist patterns It can be used for applications such as liquids for liquids and material liquids for three-dimensional modeling.

Further, the ``device for ejecting liquid'' includes a device in which a liquid ejection head and an object to which liquid can be adhered move relatively, but is not limited to this. Specific examples include a serial type device in which the liquid ejection head is moved and a line type device in which the liquid ejection head is not moved.

In addition, as a "liquid ejecting device", there are other processing liquid coating devices that eject processing liquid onto the paper in order to apply the processing liquid to the surface of the paper for the purpose of modifying the surface of the paper, raw materials is dispersed in a solution, and sprays a composition liquid through a nozzle to granulate fine particles of the raw material.

Further, the terms used in the present application, such as image formation, recording, printing, printing, printing, modeling, etc., are synonymous.

EXAMPLES The present invention will be described in more detail below with reference to Examples and Comparative Examples, but the present invention is not limited to these Examples. In addition, below, "%" represents "mass %" unless otherwise specified.

<Preparation of active energy ray-curable composition>
Active energy ray-curable compositions were prepared at the compounding ratios shown in Tables 1 and 2 (% by mass relative to the total amount of the active energy ray-curable composition).

<Silica particle dispersion>
As the silica particles, commercially available silica sol was used, and when the silica dispersion medium was water, the solvent was replaced with ethanol once and then with acryloylmorpholine. When methyl ethyl ketone was the dispersion medium, it was removed by solvent replacement with acryloylmorpholine. That is, acryloylmorpholine having low volatility was added to the silica dispersion and then removed using an evaporator. The silica particle dispersion obtained here (solid content ratio of 50% as a single unit) was added to the above active energy curable composition so that the solid content ratio shown in Tables 1 and 2 was obtained, and the ink and did.

<<Silica particles>>
(1) MP-1040 (Nissan Chemical Industries) (average particle size 100 nm [BET method])
(2) MEK-ST-2040 (Nissan Chemical Industries) (average particle size 200 nm [centrifugal sedimentation method])
(3) MP-4540m (Nissan Chemical Industries) (average particle size 450 nm [dynamic light scattering method])
(4) MEK-ST-L (Nissan Chemical Industries) (average particle size 40-50 nm [BET method])

<Production of cured product>
In Examples 1 to 9 and Comparative Examples 3 to 5, each of the obtained active energy ray-curable inks was coated with polycarbonate so as to have an average thickness of 10 μm using an apparatus having a circulation mechanism shown in FIGS. Each ink was discharged onto a substrate (Mitsubishi Engineering-Plastics, Iupilon 100FE2000 masking, thickness 100 μm).
In Comparative Examples 1 and 2, an apparatus without a circulation mechanism was used. Using an inkjet ejection device equipped with a GEN4 head (manufactured by Ricoh Printing Systems Co., Ltd.), ink was similarly ejected onto a polycarbonate base material so as to have an average thickness of 10 μm. Immediately after the discharge, ultraviolet rays were irradiated at a light amount of 1,500 mJ/cm ² using a UV irradiator LH6 manufactured by Fusion Systems Japan to obtain each cured product.

(evaluation)
The following evaluations were performed. Tables 1 and 2 show the results. In Table 2, "-" in Comparative Examples 2 and 3 means no evaluation.

<Stretchability>
Stretchability was evaluated by elongation at break at 180°C (tensile test). The prepared cured product was measured using a tensile tester (Autograph AGS-5kNX, manufactured by Shimadzu Corporation) under the conditions of tensile speed: 20 mm / min, temperature 180 ° C., sample: JIS K6251 dumbbell shape (No. 6), The stretchability was expressed by the ratio of (length after tensile test−length before tensile test)/(length before tensile test). The evaluation criteria were as follows. Acceptance criteria are not particularly defined, but B or higher is preferable, and A is more preferable.

[Evaluation criteria]
A: 200% or more B: 100% or more and less than 200% C: 50% or more and less than 100% D: less than 50%

<Homogeneity of Gloss>
The gloss uniformity of the cured product was visually evaluated, and the evaluation criteria were as follows. A and B were rated as passing, and C was rated as failing.

[Evaluation criteria]
A: The cured product as a whole has a homogeneous glossiness.
B: Glittering feeling and matte feeling are partly worrisome, but the glossiness is sufficiently durable for practical use.
C: Glittering feeling and matte feeling are remarkable, gloss is uneven, and the quality is not suitable for practical use.

<Matte property>
Regarding the evaluation of the matte property, the evaluation criteria were as follows, A and B were regarded as acceptable, and C was regarded as unacceptable. The 60° gloss and haze values were determined as follows.

[Evaluation criteria]
A: 60° gloss of 40 or less and haze value of 20 to 50
B: 60° gloss of 60 or less and haze value of 10 to 50
C: Not applicable to conditions A and B

<<Glossiness>>
Glossiness was measured at 60° using Micro Trigloss (manufactured by BYK). At this time, measurements were taken at 5 arbitrary points on the cured product, and the average value was taken as the glossiness.

<<Haze>>
Haze was measured using NDH4000 (manufactured by Nippon Denshoku Industries Co., Ltd.) in accordance with JIS-K-7136.

<Pencil hardness>
The pencil hardness test was conducted according to JIS K5600-5-4 scratch hardness (pencil method). As a device, a scratch pencil hardness TQC WW tester (load 750 g only) manufactured by COTEC Co., Ltd. is used, and the pencil is attached to the coated surface so as to be pressed at an angle of 45° and a load of 750 g. Tests were performed at speeds of 0.5 to 1 mm/s. 3B or more was regarded as a pass.

<Ejection stability>
The cured product was visually observed and evaluated for the presence or absence of streaks, voids, and jet disturbance. The evaluation criteria at this time were as follows, with A passing and B and C failing.

[Evaluation criteria]
A: No or almost no streaks, omissions, or ejection disturbances observed in the solid portion.
B: Streaks, omissions, and ejection disturbances are observed at three or more locations in the solid portion.
C: No ink was ejected and no image was formed.

(1) Ejection stability: According to a comparison between Examples 1 to 9 and Comparative Examples 1 and 2, ink containing fine particles having an average primary particle size of 100 to 200 nm can be obtained only by ejecting it with an apparatus having a circulation mechanism. It turns out that it becomes possible to make it discharge stably.
(2) Ejection stability: A comparison of Examples 1 to 9 and Comparative Example 3 shows that fine particles having a particle size larger than 200 nm cannot be ejected even if they are ejected by an apparatus having a circulation mechanism.
(3) Stretchability: From Examples 1 to 9, it can be seen that the stretchability varies depending on the content of the monofunctional monomer.
(4) Homogeneity of glossiness: According to a comparison between Examples 1 to 9 and Comparative Examples 1 to 5, ink containing microparticles with an average primary particle size of 100 to 200 nm can be obtained only by discharging from a device having a circulation mechanism. It can be seen that the glossiness can be made uniform.
(5) Matte property: A comparison between Examples 1 to 9 and Comparative Example 4 shows that sufficient matte property cannot be obtained when fine particles are not contained in the ink.
(6) Matte property: A comparison between Examples 1 to 9 and Comparative Example 5 shows that sufficient matte property cannot be obtained when the particle diameter of the fine particles is smaller than 100 nm.
(7) Pencil hardness: From Examples 1 to 9, it can be seen that the lower the addition amount of the polyfunctional monomer having a functional group of two or more, the lower the hardness.

(Figures 4 to 12)
REFERENCE SIGNS LIST 1 nozzle plate 2 flow path plate 3 vibration plate member 4 nozzle 6 individual liquid chambers 6a, 6b, 6c, 6d, 6e through grooves forming individual liquid chambers 7 fluid resistance portion 7a through groove portion as fluid resistance portion 8 liquid introduction portion 8a, 8b through-groove portion constituting a liquid introducing portion 9 filter portion 10 common liquid chamber 10A downstream side common liquid chamber 10a through-groove portion 10B upstream side common liquid chamber 10b groove portion 11 piezoelectric actuator 12 piezoelectric member 12A, 12B piezoelectric element 13 base member 15 Flexible wiring member 20 Common liquid chamber member 21 First common liquid chamber member 22 Second common liquid chamber member 25a, 25b Piezoelectric actuator through hole 29 Cover 30 Vibration region 30a, 30b Convex portion 40 Flow path member 41 to 45 Plate member 50 circulation common liquid chamber 50a groove portion 51 fluid resistance portion 51a through groove portion constituting the fluid resistance portion 52, 53 circulation flow paths 52a, 52b through groove portions constituting the circulation flow path 53a, 53b, 53c, 53d constituting the circulation flow path Through groove portion 71 Supply port 71a Through hole 81 Circulation port 81a, 81b Through hole

JP 2015-117359 A JP 2017-131865 A

Claims (5)

A device for ejecting liquid, comprising a liquid and a liquid ejection head,
The liquid ejection head includes an individual liquid chamber that communicates with a nozzle that ejects the liquid, an inflow channel that allows the liquid to flow into the individual liquid chamber, and a flow path that allows the liquid to flow out of the individual liquid chamber. and an outflow channel;
The liquid is circulated through the inflow channel and the outflow channel, is made of an active energy ray-curable composition, and contains fine particles having an average primary particle size of 100 nm to 200 nm and a polymerizable compound,
the fine particles are silica particles ,
The polymerizable compound includes a monofunctional monomer and a polyfunctional monomer having a functional group of two or more,
A device for ejecting liquid , wherein the monofunctional monomer is contained in an amount of 50% by mass or more with respect to the total amount of the polymerizable compound . 2. The apparatus for ejecting liquid according to claim 1 , further comprising irradiation means for irradiating active energy rays. 3. The apparatus for ejecting liquid according to claim 1, wherein said silica particles are contained in said liquid in an amount of 10% by mass or more and 20% by mass or less. a supply tank for flowing the liquid into the liquid ejection head;
a circulation tank into which the liquid flows out from the liquid ejection head;
a pressure sensor provided between at least one of the liquid ejection head and the supply tank and between the liquid ejection head and the circulation tank;
4. The apparatus for ejecting liquid according to claim 1 , further comprising a circulation speed control section that controls the circulation speed of the liquid according to the detection value of the pressure sensor. 5. The apparatus for ejecting liquid according to claim 4 , wherein the circulation speed control unit increases the circulation speed of the liquid when the detected value of the pressure sensor is smaller than a predetermined value.

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