JP2008233815A - Liquid developer - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a liquid developer having stable charging characteristics and allowing a toner layer to be inexpensively formed with high resolution and high accuracy, by improving charging property of the toner without increasing an addition amount of a charge control agent. <P>SOLUTION: The developer includes toner particles dispersed in an electric insulating solvent, wherein the toner particle comprises a core particle, a coating layer comprising thermoplastic resin fine particles coating the core particle, and a charge control agent and an organic compound having a nonionic functional group with an unpaired electron, added to the coating layer surface. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a liquid developer that can be developed using an electrophoresis technique.

  Conventionally, a photolithography technique has played a central role as a technique for forming a fine pattern on the surface of a substrate. However, while this photolithography technology is increasing its resolution and performance, it requires huge and expensive manufacturing equipment, and the manufacturing cost is also increasing according to the resolution.

  On the other hand, in the manufacturing field of image display devices and the like as well as semiconductor devices, there is an increasing demand for cost reduction as well as performance improvement. However, the above photolithography technique cannot sufficiently satisfy such a requirement.

  Under such circumstances, a pattern forming technique using a digital printing technique is attracting attention. For example, inkjet technology has begun to be put into practical use as a patterning technology that makes use of features such as simplicity of the apparatus and non-contact patterning. However, there has been a limit to high resolution and high productivity.

  On the other hand, the electrophoretic technique including the electrophotographic technique using the liquid toner has an excellent possibility regarding low cost, high resolution, and high productivity. For example, a technique for forming a phosphor layer of a front substrate for a flat panel display using such an electrophoresis technique has been proposed (see, for example, Patent Document 1). In this method, a resin composed of a core portion that is insoluble or swelled in an insulating solvent and an outer edge portion that swells or dissolves in the insulating solvent is used as a resin component that covers the surface of the phosphor toner particles. In addition, a dispersant and a charge control agent are added in order to impart particle dispersion and chargeability in the electrodeposition liquid.

  In order to increase the resolution, it is important to control the behavior of individual toner particles, and when using an electrophoresis technique, control of the chargeability of the toner particles is an important factor.

  Here, in order to control the chargeability of the toner particles using the charge control agent, the interaction of the charge control agent on the toner particle surface is important. Depending on the type of the charge control agent, the chargeability varies greatly depending on the difference in the adsorption / coordination state on the toner particle surface and the surface state of the toner particle even with the same charge control agent. For example, even if the amount of charge control agent added is increased, if the amount of adsorption / coordination on the surface of the toner particles is saturated, the chargeability of the toner particles cannot be further increased.

  As described above, when the toner particle surface is coated with a resin, the charge control agent is adsorbed on the surface of the core particle of the toner particle, or is coordinated with acid / base to the functional group on the surface. Takes charge to reduce chargeability. Here, not all the adsorption sites and coordination sites on the toner particle surface are in a uniform surface state, but a non-uniform surface state is taken due to the molecular weight of the resin, the non-uniform arrangement of functional groups, and steric hindrance. . When the charge imparting property is small with respect to the surface state of such particles, the influence of the surface state is large, the chargeability of the particle surface becomes non-uniform, and particles having no sufficient charge amount are generated. As a result, it is difficult to control the coated resin surface in a uniform state, and uniform and sufficient chargeability cannot be stably imparted to individual toner particles. As a result, it was difficult to electrodeposit a high-definition toner layer.

  In such a case, for example, by adjusting the addition amount of the charge control agent, it is also possible to manage the charge amount more than the saturation charge amount. In the case of a charge control agent that adversely affects the properties of the toner particles, there is a limit to the amount added, making it difficult to cope with it. In addition, in the case of a charge control agent having a low charge imparting property, toner particles with insufficient chargeability are also present.

Therefore, optimal toner design becomes difficult.
Japanese Patent Laid-Open No. 9-202995

  The present invention has been made to solve such a problem, and its purpose is to stabilize the charging characteristics by improving the chargeability of the toner without increasing the amount of the charge control agent added. Another object is to provide a liquid developer capable of forming a toner layer with high resolution, high accuracy, and low cost.

  The liquid developer of the present invention includes an electrically insulating solvent, core particles dispersed in the electrically insulating solvent, a thermoplastic resin particle coating layer provided on the surface of the core particle, and a surface of the thermoplastic resin particle coating layer. And a toner particle containing a charge control agent and an organic compound having a nonionic functional group having an unpaired electron.

  When the liquid developer of the present invention is used, the chargeability is improved without increasing the amount of charge control agent added, and excellent dispersibility can be obtained, whereby the toner layer can have high resolution, high accuracy, and It can be formed at low cost.

  The liquid developer of the present invention includes an electrically insulating solvent and toner particles.

  The toner particles include a core particle and a thermoplastic resin particle coating layer coated on the core particle surface, and the surface of the thermoplastic resin particle coating layer has a nonionic functional group having a charge control agent and an unpaired electron. An organic compound having a group is added.

  According to the present invention, by using an organic compound having a nonionic functional group having an unpaired electron together with a charge control agent, the charge control agent is more stable on the surface of the thermoplastic resin particle coating layer surface. Can be adsorbed on the surface, or can be coordinated with acid or base with respect to the functional group on the surface. That is, when an organic compound having a nonionic functional group having an unpaired electron is added, the chargeability of the particle surface can be improved. This is presumably because the unpaired electron portion is in a coordinated state with respect to the charged portion, resulting in a more stable charged state.

  As a result, according to the present invention, it is possible to use a charge control agent having a relatively low charge imparting property and a charge control agent whose use amount is limited because it has an adverse effect on the core particles. Since the width can be expanded, it is easy to design an optimal toner composition.

  In addition, according to the present invention, the chargeability of the toner particle surface is increased, whereby the charge amount of each toner particle can be stabilized at a high level, and a sufficient charge amount for electrophoresis can be maintained. Therefore, the electrophoretic control is good and a high-definition toner layer can be electrodeposited. Further, the dispersibility of the toner particles due to the electric repulsion in the toner solution is improved by improving the chargeability of the individual particles.

  Thus, when the present invention is used, sufficient chargeability can be obtained without increasing the amount of charge control agent added. Thereby, the toner dispersibility is improved, and the toner layer can be formed with high resolution, high accuracy, and low cost.

  FIG. 1 is a schematic diagram showing the state of the toner particle surface of an example of the liquid developer of the present invention.

  As shown in the drawing, the thermoplastic resin fine particles adhering to the surface of the core particle 60, for example, the oxygen atom of the ester group or carboxyl group on the surface of the acrylic fine particle, and the charge control agent, for example, the metal portion (metal cation M +) of the metal soap. By preferentially coordinating, the toner particles are charged. The stability of the coordination state of the metal cation is unlikely to be all the same because the stable coordination number and coordination structure differ depending on the metal cation. In other words, since the ester groups and carboxyl groups on the surface of the acrylic fine particles covering the particles are fixed to the resin, a completely stable coordination number and coordination structure cannot be given to all metal cations. If nonionic ketones with unpaired electrons are added here, it can act as a free ligand, so the metal cation is thought to be kept in a more stable coordination number and coordination structure, Therefore, it is considered that the charging property is improved. As described above, in the present invention, the organic compound having a nonionic functional group having an unpaired electron can interact with the charge control agent on the surface of the thermoplastic resin particle coating layer to improve the chargeability. .

  In the thermoplastic resin particle coating layer, the thermoplastic resin particles cover at least part of the toner particle surface.

  Further, in the liquid developer, the charge control agent present in the electrically insulating solvent and at least a part of this organic compound are added to the surface of the thermoplastic resin particle coating layer and adsorbed or coordinated. . The remaining charge control agent and the organic compound may be present in the electrically insulating solvent without acting on the surface of the thermoplastic resin particle coating layer.

  The organic compound having a nonionic functional group having an unpaired electron used in the present invention preferably has at least one functional group of a sulfide group, a ketone group, an amide group and a nitrile group.

  The addition amount of the organic compound having a nonionic functional group having an unpaired electron is preferably 0.1 to 10% by weight based on the solid content weight of the charge control agent.

  The core particles preferably have an average particle size of 0.01 to 10 μm. When the average particle size is less than 0.01 μm, the intermolecular aggregation of the core particles tends to be large, and uniform dispersion tends to be difficult. Thus, when using core particles with a small average particle size and poor dispersibility (for example, fine pigment particles having an average particle size of several nm), they can be supported on a resin having a larger average particle size. it can. Thereby, dispersibility can be improved and applied. If it exceeds 10 μm, it is difficult to uniformly stir the core particles, and as a result, it tends to be difficult to form a uniform resin layer.

  The charge control agent used in the present invention is preferably an organic compound containing at least one of a metal soap, a surfactant, a metal complex, and a metal alkoxide, and the content thereof is based on the weight of the core particles. It contains a metal content corresponding to 0.001 to 10% by weight.

  The weight ratio of the toner particles to the insulating solvent is preferably 2:98 to 50:50 with respect to 100 parts by weight of the liquid developer.

  When the weight ratio of the toner particles is larger than the above range, a large amount of solvent is required to obtain a predetermined film thickness, or when the weight ratio of the solvent is larger than the above range, the toner particles other than the portion where the film is to be formed It tends to adhere and cause contamination.

  The charge control agent preferably contains a metal component corresponding to 0.001 to 10% by weight based on the weight of the core particle.

  If the content of the charge control agent is less than 0.001% by weight based on the toner particles, there are many particles that cannot be controlled by the electric field due to insufficient charging of the toner, and the electrodeposition film flows or forms a film. There is a tendency that toner particles adhere to other than the part and cause contamination.

  When the content of the charge control agent exceeds 10% by weight with respect to the toner particles, the amount of ionic components in the developer becomes excessive, and the resistance of the entire developer becomes too low, so that the electrophoretic properties of the toner particles are lowered. Tend.

  In consideration of these problems, more preferably, these charge control agents are added in an amount of 0.01 to 2% by weight based on the core particles.

  The content of the organic compound having a nonionic functional group is preferably 0.1 to 10% by weight based on the solid content weight of the charge control agent. If it is less than 0.1% by weight, the amount of coordination to the charged portion is too small, and a sufficient effect of improving the charge amount is not observed. Further, if the content exceeds 10% by weight, the material itself does not have charging properties. Therefore, when the content is excessive, it adversely affects the electrophoresis of the toner.

  The content of the thermoplastic resin fine particles preferably corresponds to 1.0 to 20% by weight with respect to the weight of the core particles.

  If the content of the thermoplastic resin fine particles is less than 1% by weight with respect to the core particles, the amount of the resin adhering or adsorbing is too small, so that the core particles are exposed such as the presence of the core particles to which no resin is adhered. Establishing to be higher. Therefore, the surface state of the core particles becomes non-uniform, and therefore, the distribution of the charge control agent becomes non-uniform, and it tends to be difficult to control the chargeability of the toner particles. Further, when the content of the thermoplastic resin fine particles exceeds 20% by weight, the thermoplastic resin fine particles become excessive with respect to the core particles, and the thermoplastic resin fine particles that cannot be attached or adsorbed to the core particles are obtained. There is a tendency to be adsorbed to the thermoplastic resin fine particles which are liberated in the solution and the charge control agent is liberated, thereby inhibiting the charging characteristics of the toner particles. Taking these problems into consideration, the content of these thermoplastic resin fine particles is more preferably 3 wt% or more and 10 wt% or less with respect to the core particles.

  The organic compound having a nonionic functional group used in the present invention is preferably a compound having a sulfide group, a ketone group, an amide group or a nitrile group, and examples of such a compound include di-n. -Propyl disulfide, diallyl disulfide, dibutyl disulfide, 3-octanone, acetylacetone, 2,3-heptanedione, 6-methyl-2,4-heptanedione, 5-methyl-3-heptanone, 1-n-octyl- Examples include 2-pyrrolidone, N, N-dibutylformamide, lauronitrile, and acetonitrile.

  Examples of the core particles include phosphor particles, pigment particles, and colored resin particles containing a colorant.

As phosphors usable in the present invention, Y ₂ O ₃ : Eu, YVO ₄ : Eu, (Y, Gd) BO ₃ : Eu, Y ₂ O ₂ S: Eu, γ-Zn ₃ (PO ₄ ) ₂ : Mn, (ZnCd) S: Ag + InO ( or _{red), Zn 2 GeO 2: Mn} , BaAl 12 O 19: Mn, Zn 2 SiO 4: Mn, LaPO 4: Tb, ZnS: (Cu, Al), ZnS: _{(Au, Cu, Al),} (ZnCd) S: (Cu, Al), Zn 2 SiO 4: (Mn, As), Y 3 Al 5 O 12: Ce, Gd 2 O 2 S: Tb, Y 3 Al ₅ O ₁₂ : Tb, ZnO: Zn (above green), Sr ₅ (PO ₄ ) 3CI: Eu, BaMgAl ₁₄ O ₂₃ : Eu, BaMgAl ₁₆ O ₂₇ : Eu, ZnS: Ag + red pigment, Y ₂ SiO ₃ : Ce (Above blue Color).

  As the material of the pigment particles, inorganic pigments, organic pigments, and the like can be used.

  Specific examples of inorganic pigments include natural pigments such as ocher, yellow lead, zinc yellow, barium yellow, chromate such as chrome orange, molybdenum red and chrome green, ferrocyan compounds such as bitumen, titanium oxide, titanium yellow , Titanium white, bengara, yellow iron oxide, zinc oxide, zinc ferrite, zinc white, iron black, cobalt blue, chromium oxide, spinel green and other oxides, sulfides such as cadmium yellow, cadmium orange, cadmium red, barium sulfate And sulfates such as calcium silicate, silicates such as ultramarine, metal powders such as bronze and aluminum, and carbon black.

  Specific examples of organic pigments include, for example, natural lakes such as Madare Lake, nitrone pigments such as naphthol green and naphthol orange, benzidine yellow G, Hansa Yellow G, Hansa Yellow 10G, Vulcan Orange, Lake Red R, Lake Red C, Rake Red D, Watching Red, Brilliantamine 6B, Pyrarozone Orange, Bordeaux 10G, (Formaloon) and other soluble azo, Pyrarozone Red, Parared, Toluidine Red, ITR Red, Toluidine Red (Rake Red 4R), Toluidine Maroon, Insoluble azo pigments such as brilliant fist scarred and lake bordeaux 5B, condensed azo pigments such as condensed azo pigments, phthalocyanine blue, phthalocyanine green, brominated phthalocyanine green, fasts Phthalocyanine pigments such as iBlue, anthraquinones such as selenium blue, perylenes such as perylene maroon, perinones such as perinoo orange, quinacridones such as quinacridone and dimethylquinacridone, dioxazines such as dioxazine violet, isoindoline, quinophthalone Condensed polycyclic pigments such as rhodamine, basic dye lakes such as rhodamine 6B, lake, rhodamine lake B, malachite green, and mordant dye pigments such as alizarin lake, induslen blue, indigo blue, and anthrone orange Examples thereof include dye dye pigments, fluorescent pigments, azine pigments (diamond black), and green gold.

  As resin materials for resin particles used for colored resin particles containing a colorant, styrene, o-methylstyrene, m-methylstyrene, p-methylstyrene, p-methoxystyrene, p-phenylstyrene, p-chloro Styrene, 3,4-dichlorostyrene, p-ethylstyrene, 2,4-dimethylstyrene, pn-butylstyrene, p-tert-butylstyrene, pn-hexylstyrene, pn-octylstyrene, Styrene and derivatives thereof such as pn-nonyl styrene, pn-decyl styrene, pn-dodecyl styrene; ethylene unsaturated monoolefins such as ethylene, propylene, isobutylene; vinyl chloride, vinylidene chloride, vinyl fluoride Vinyl halides such as vinyl acetate, vinyl propionate, vinyl benzoate Vinyl esters such as methyl methacrylate; methyl methacrylate, ethyl methacrylate, propyl methacrylate, n-butyl methacrylate, isobutyl methacrylate, n-octyl methacrylate, dodecyl methacrylate, 2-ethylhexyl methacrylate, stearyl methacrylate, Α-methylene aliphatic monocarboxylic acid esters such as phenyl methacrylate, dimethylaminoethyl methacrylate, diethylaminoethyl methacrylate; methyl acrylate, ethyl acrylate, n-butyl acrylate, isobutyl acrylate, propyl acrylate, acrylic Acrylic acid esters such as n-octyl acid, dodecyl acrylate, 2-ethylhexyl acrylate, stearyl acrylate, 2-chloroethyl acrylate, phenyl acrylate, etc .; vinyl methyl ether Vinyl ethers such as tellurium, vinyl ethyl ether, vinyl isobutyl ether; vinyl ketones such as vinyl methyl ketone, vinyl hexyl ketone, methyl isopropenyl ketone; N-vinyl pyrrole, n-vinyl carbazole, N-vinyl N-vinyl compounds such as indole and N-vinylpyrrolidone; vinyl naphthalic acid; homopolymers or copolymers such as vinyl monomers such as acrylic acid and methacrylic acid derivatives such as acrylonitrile, methacrylonitrile, and acrelamide Can give. Particularly representative binder resins include polystyrene, styrene-acrylic acid copolymer, styrene-methacrylic acid co-aggregate, styrene-acrylonitrile co-aggregate, styrene-butadiene co-aggregate, polyester, polyurethane, epoxy resin, and silicon. Examples thereof include resins and polyamides.

  The charge control agent used in the present invention includes, for example, organic acid metal salts such as naphthenic acid Zr, octylic acid Mg, lauric acid Zr, oleic acid Mg, and secanoic acid Y, chelate complex compounds such as acetylacetone Ti complex, Zr alkoxide, Ti alkoxide and the like can be mentioned.

The electrically insulating solvent used in the liquid developer of the present invention preferably has a boiling point in the temperature range of 70 to 250 ° C. and has a volume resistivity of 10 ⁹ Ω · cm or more, preferably 10 ¹⁰ to 10 ¹⁷ Ω · cm. And a dielectric constant of less than 3.

  Examples of such an electrically insulating solvent include aliphatic hydrocarbons such as n-pentane, hexane and heptane, alicyclic hydrocarbons such as cyclopentane and cyclohexane, chlorinated alkanes, fluorinated alkanes, chlorofluorocarbons and the like. Halogenated hydrocarbon solvents, silicone oils and mixtures thereof can be used. Preferably, components such as Isopar G (registered trademark), Isopar H (registered trademark), Isopar K (registered trademark), Isopar L (registered trademark), Isopar M (registered trademark) and Isopar V (registered trademark) manufactured by Exxon Corporation are used. Branched paraffin solvent mixtures can be used.

  In addition, the thermoplastic resin fine particles used in the present invention can be produced using a polymerization method represented by, for example, a suspension conformation method or an emulsion polymerization method.

  The thermoplastic resin fine particles preferably have an average particle size of 0.1 μm to 5 μm.

  If the average particle size of the thermoplastic resin fine particles is 0.1 μm or less, the composition distribution during synthesis tends to be non-uniform, the resin component that does not adhere to or adsorb to the core particles increases, and the floating residual resin is also generated by the charge control agent. Since the toner is charged, the toner composition tends to be non-uniform and high-definition patterning tends to be difficult. On the other hand, when the average particle size is 5 μm or more, the main chain of the resin is entangled, the main chain is not easily spread in the solvent, and the adhesion or adsorption to the core particle surface tends to be non-uniform.

  As the thermoplastic resin fine particles, for example, acrylic fine particles obtained as a dried powder having a primary average particle diameter of about 0.1 μm to 5 μm can be used. Even if it is not in the form of fine particles, acrylic resin, polyester resin, polyamide resin, nylon resin, and other thermoplastic resins, which are physically pulverized with a fine pulverizer, etc. Can also be used.

  Further, as a fine pulverizer, it can be used after being finely divided in an insulating solvent by a bead mill such as a sand grinder or a ball mill.

Example FIG. 2 is a schematic diagram showing an example of an experimental apparatus that can be used in the present invention.

  As shown in the figure, this experimental apparatus includes a three-necked separable flask 30 that can be separated into upper and lower parts, a stirrer 136 having a stirring blade inserted into a central port, a stirrer 136 being driven to rotate, and a central port. An explosion-proof motor 132 for sealing the thermocouple 133 is provided in one of the mouths on both sides of the center mouth, the Dimroth reflux condenser 131, the thermocouple 133 inserted into the separable flask 130 from the other mouth, and the thermocouple 133. The relay temperature control unit 134 is connected, and the mantle heater 135 is connected to the relay temperature control unit 134.

  In this experimental apparatus, while stirring the contents of the separable flask 130 using the stirrer 136, the temperature is always measured by the thermocouple 133, and the mantle heater 35 is operated by the relay temperature control unit 134 based on the measured temperature. The temperature of the contents can be kept constant at all times. The solvent vapor from the contents is cooled and condensed by the Dimroth reflux condenser 131 and returned again into the lower container, thereby preventing an excessive increase in the pressure in the separable flask 130.

Example 1
Into a 500 ml separable flask as shown in the figure, 180 g of an insulating hydrocarbon solvent (Isopar L) manufactured by Exxon Chemical Co. having a boiling range of 191 to 205 ° C. is poured, and the average particle size is 0.4 μm and the softening point is 80 ° C. Yes, 2 g of acrylic fine particles (MP4009) made by Soken Chemical Co., Ltd., having a specific gravity of 1.0, and 18 g of ZnS: Cu, Al-based green light emitting phosphor particles (average particle size 5.6 μm) are charged, and the temperature controller is set to 100. The mixture was set to ° C. and stirred with heating. Stirring was continued at a constant temperature for 2 hours after the solution temperature reached 100 ° C, and then stirred while cooling to room temperature (25 ° C) over 1.5 hours. 1.0 g of zirconium octylate manufactured by Nippon Kagaku Sangyo Co., Ltd. as a charge control agent is added to the thus obtained phosphor particle dispersion having a solid content concentration of 10% by weight, and further nonionic having unpaired electrons. As an organic compound having the functional group, 0.05 g of 3-octanone was added to obtain a green light emitting phosphor-containing liquid developer.

  An electrodeposition film formation test was performed using the obtained liquid developer.

  FIG. 3 shows an outline of an apparatus for measuring the current value of electrophoresis.

  As shown in the figure, the device 10 includes a pair of ITO transparent electrode substrates 11 and 12 installed in a shield 19, and a switch 13 and a switch 13 provided on wiring connected to one ITO transparent electrode substrate 12. And an oscilloscope 16 connected to the amplifier 17. The power supply 14 and the oscilloscope 16 further include, for example, a personal computer or the like. A CPU 15 is connected to control the power supply 14 and the oscilloscope 16. The two ITO transparent electrode substrates 11 and 12 are arranged to face each other via a Teflon (registered trademark) spacer (not shown) to constitute a sandwich cell.

  The Teflon (registered trademark) spacer used is, for example, a square with a side of 40 mm, and a square opening of 30 mm square is provided at the center, and two paths leading to the opening are formed from that side. A part of the spacer is removed. One of the two passes can be used as an air vent and the other as a liquid developer injection path.

  Using the above apparatus, the liquid developer 18 is injected into the sandwich cell, the switch is turned on, a DC voltage of 400 V is applied for 5 seconds, and the toner particles 21 in the liquid developer 18 are electrophoresed on the ITO transparent electrode substrate 11 side. And then switched off. At this time, the electrophoretic current value was measured with the oscilloscope 16, and the data processing was performed with the CPU 15 based on the obtained measurement data to obtain the electrophoretic current waveform. A graph showing an electrophoretic current waveform relating to the obtained liquid developer is shown in FIG.

  As shown in the figure, the current value showed a peak within 0.1 seconds after the voltage was applied, and it suddenly decreased to some extent. Here, it can be seen that the toner particles are electrodeposited on the ITO transparent electrode substrate 11. Thereafter, the current value gradually decreased, and after 0.3 seconds, it decreased to about 0.33 μA and became a steady current.

  Here, the integral value of the current waveform as shown below is used as the charge amount of the entire toner particles in this measurement system.

Charge amount Q (μC) of entire toner particles = ∫idt
Where i is the electrophoretic current.

  Further, the charge amount per μg of toner particles (μC / g) was obtained by dividing the charge amount Q of the entire toner particles by the weight of the electrodeposited film.

  The integrated value per 1 g of toner particles was found to be 37.4 μC / g.

  Thereafter, the sandwich cell was disassembled, and the state of the electrodeposition film obtained on the surface of the ITO transparent electrode substrate 11 was observed.

  As a result, a uniform phosphor electrodeposition film was formed on the ground side ITO transparent electrode substrate 11, and nothing adhered to the positive electrode side ITO transparent electrode substrate 12. This confirmed that all the toner particles in the liquid developer are charged positively, and there are no toner particles with insufficient chargeability.

  Table 1 below shows the charge amount of the toner obtained by the electrodeposition film formation test and the state of the electrodeposition film.

  In the table, the state of the electrodeposition film is a case where a uniform electrodeposition film by toner particles is formed on the ITO transparent electrode substrate 11 on the ground side and nothing is attached to the ITO transparent electrode substrate 12 on the positive electrode side. The case where some adhesion was observed was evaluated as Δ, and the case where toner particle adhesion on the positive electrode side ITO transparent electrode substrate 12 was found to be equal to or greater than that on the positive electrode side ITO transparent electrode substrate 12 was evaluated as x.

  Here, the softening point is JIS K 7206: 1999 Plastic-thermoplastic-Vicat softening temperature (VST) test method: Plastic-Thermoplastic materials-degradation of Vicat softening temperature (VST): 1994 As described above, the temperature of the heat transfer medium when the needle-like indenter penetrates 1 mm is increased by heating the medium at a constant speed while applying a predetermined load through a needle-like indenter perpendicular to the test piece of the heating bath or the heating phase. Say.

Example 2
The amount of the organic compound having a nonionic functional group having a charge control agent and an unpaired electron to be added to the phosphor particle dispersion having a solid content concentration of 10% by weight, 0.2 g of zirconium octylate, 3- A green light-emitting phosphor-containing liquid developer was obtained in the same manner as in Example 1 except that octanone was changed to 0.01 g.

  Using the obtained liquid developer, an electrodeposition film formation test was conducted in the same manner as in Example 1.

  The green light emitting phosphor-containing liquid developer thus obtained has a charge amount (μC / g) determined from the current value during electrodeposition of 19.1 μC / g, and the electrodeposition film is ground. A uniform electrodeposition film of toner particles was formed on the ITO transparent electrode substrate 11 on the side, and nothing adhered to the ITO transparent electrode substrate 12 on the positive electrode side. Table 1 shows the measurement results of the charge amount and the state of the electrodeposition film.

Comparative Example 1
A green light emitting phosphor-containing liquid developer was obtained in the same manner as in Example 1 except that 3-octanone was not added to the phosphor particle dispersion having a solid content concentration of 10% by weight.

  Using the obtained liquid developer, an electrodeposition film formation test was conducted in the same manner as in Example 1.

  The green light emitting phosphor-containing liquid developer thus obtained has a charge amount (μC / g) determined from the current value at the time of electrodeposition is 22.01 μC / g. A uniform electrodeposition film of toner particles was formed on the ITO transparent electrode substrate 11 on the side, and nothing adhered to the ITO transparent electrode substrate 12 on the positive electrode side. Table 1 shows the measurement results of the charge amount and the state of the electrodeposition film.

  Compared to Example 1 above, Example 1 had a charge amount of about 1.7 times that of Comparative Example 1, and it was confirmed that the charge amount of the toner was improved by the effect of adding 3-octanone.

Comparative Example 2
A green light emitting phosphor-containing liquid developer was obtained in the same manner as in Example 2 except that 3-octanone was not added to the phosphor particle dispersion having a solid content concentration of 10% by weight.

  Using the obtained liquid developer, an electrodeposition film formation test was conducted in the same manner as in Example 1.

  The green light emitting phosphor-containing liquid developer thus obtained has a charge amount (μC / g) determined from the current value during electrodeposition is 8.7 μC / g, and the electrodeposition film is a ground. An electrodeposition film composed of about 70% of the toner particles was formed on the ITO transparent electrode substrate 11 on the side, but about 30% of the toner particles adhered to the ITO transparent electrode substrate 12 on the positive electrode side. Was. Table 1 shows the measurement results of the charge amount and the state of the electrodeposition film.

Compared to Example 2, in Comparative Example 2, about 30% of the toner particles adhered to the ITO electrode on the positive electrode side. Therefore, when 3-octanone was not added, particles with insufficient chargeability The existence was suggested.

Example 3
An organic compound having a nonionic functional group having a charge control agent and an unpaired electron added to a phosphor particle dispersion having a solid content concentration of 10% by weight, 1.0 g of calcium octylate manufactured by Nippon Chemical Industry, In addition, a green light emitting phosphor-containing liquid developer was obtained in the same manner as in Example 1 except that the amount of dibutyl disulfide was changed to 0.05 g.

  Using the obtained liquid developer, an electrodeposition film formation test was conducted in the same manner as in Example 1.

  The green light emitting phosphor-containing liquid developer thus obtained has a charge amount (μC / g) determined from the current value at the time of electrodeposition, which is 14.3 μC / g. A uniform electrodeposition film of toner particles was formed on the ITO transparent electrode substrate 11 on the side, and nothing adhered to the ITO transparent electrode substrate 12 on the positive electrode side.

  This confirmed that all of the developer was positively charged and there were no particles with insufficient chargeability.

  The measurement results of the charge amount and the state of the electrodeposition film are shown in Table 2 below.

Example 4
The amount of the organic compound having a nonionic functional group having a charge control agent and unpaired electrons to be added to a phosphor particle dispersion having a solid content concentration of 10% by weight, calcium octylate 5.0 g, dibutyl disulfide A green light emitting phosphor-containing liquid developer was obtained in the same manner as in Example 3 except that the amount was changed to 0.25 g.

  Using the obtained liquid developer, an electrodeposition film formation test was conducted in the same manner as in Example 1.

  The green light emitting phosphor-containing liquid developer thus obtained has a charge amount (μC / g) determined from the current value during electrodeposition of 20.2 μC / g, and the electrodeposition film is ground. A uniform electrodeposition film of toner particles was formed on the ITO transparent electrode substrate 11 on the side, and nothing adhered to the ITO transparent electrode substrate 12 on the positive electrode side. This confirmed that all of the developer was positively charged and there were no particles with insufficient chargeability.

  The measurement results of the charge amount and the state of the electrodeposition film are shown in Table 2 below.

Comparative Example 3
A green light-emitting phosphor-containing liquid developer was obtained in the same manner as in Example 3 except that dibutyl disulfide was not added to the phosphor particle dispersion having a solid content concentration of 10% by weight.

  Using the obtained liquid developer, an electrodeposition film formation test was conducted in the same manner as in Example 1.

  The green light emitting phosphor-containing liquid developer thus obtained has a charge amount (μC / g) determined from the current value at the time of electrodeposition is 4.1 μC / g, and the electrodeposition film is a ground. On the ITO electrode 11 on the side, about 20% of the phosphor electrodeposition film of the entire toner particles was formed. On the other hand, about 80% of the phosphor particles adhered to the ITO electrode 12 on the positive electrode side.

  As a result, it was found that most of the toner particles are insufficiently charged particles.

  The measurement results of the charge amount and the state of the electrodeposition film are shown in Table 2 below.

  Compared with Example 3, the charge amount of Example 3 was about 3.5 times that of Comparative Example 3, and it was confirmed that the charge amount of the toner was improved by the addition effect of dibutyl disulfide.

  However, in Comparative Example 3, about 80% of the particles were adhered to the ITO electrode on the positive electrode side. Therefore, it is considered that a large number of particles with insufficient chargeability exist when no dibutyl disulfide is added.

Comparative Example 4
A green light emitting phosphor-containing liquid developer was obtained in the same manner as in Example 4 except that dibutyl disulfide was not added to the phosphor particle dispersion having a solid content concentration of 10% by weight.

  Using the obtained liquid developer, an electrodeposition film formation test was conducted in the same manner as in Example 1.

  The green light emitting phosphor-containing liquid developer thus obtained has a charge amount (μC / g) determined from the current value during electrodeposition is 5.7 μC / g, and the electrodeposition film is About 60% of the phosphor electrodeposition film was formed on the ground-side ITO electrode 11, and about 40% of the phosphor particles adhered to the ITO electrode 12 on the positive electrode side.

  From this, it was found that there were particles with insufficient chargeability.

  The measurement results of the charge amount and the state of the electrodeposition film are shown in Table 2 below.

  Compared to Example 4, Example 4 had a charge amount of about 3.5 times that of Comparative Example 4, and it was confirmed that the charge amount of the toner was improved due to the addition effect of dibutyl disulfide.

However, in Comparative Example 4, about 40% of the particles were adhered to the ITO electrode on the positive electrode side. Therefore, when dibutyl disulfide is not added, it is considered that there are particles with insufficient chargeability.

Schematic diagram showing the state of the toner particle surface of an example of the liquid developer of the present invention Schematic showing an example of an experimental apparatus that can be used in the present invention Device for measuring the current value of electrophoresis The graph figure showing the electrophoretic current waveform about an example of the liquid developer of the present invention

Explanation of symbols

  DESCRIPTION OF SYMBOLS 10 ... Electrophoresis electric current value measuring apparatus 11, 12 ... ITO electrode, 13 ... Switch, 14 ... Power supply, 15 ... CPU, 16 ... Oscilloscope, 17 ... Amplifier, 19 ... Shield, 60 ... Toner particle, 61 ... Nuclear particle, 62 ... Coating layer, 63 ... Thermoplastic resin fine particles, 131 ... Dimroth reflux condenser, 132 ... Explosion-proof motor, 133 ... Thermocouple, 134 ... Relay temperature control unit, 135 ... Mantle heater, 136 ... Stirrer

Claims (7)

  Electrical insulating solvent, core particles dispersed in the electrical insulating solvent, thermoplastic resin particle coating layer provided on the surface of the core particle, and charge control agent added to the surface of the thermoplastic resin particle coating layer And a toner containing an organic compound having a nonionic functional group having an unpaired electron.   The nonionic organic compound having an unpaired electron has at least one functional group selected from the group consisting of a sulfide group, a ketone group, an amide group, and a nitrile group. The liquid developer as described.   3. The liquid development according to claim 1, wherein the nonionic organic compound having unpaired electrons is added in an amount of 0.1 to 10% by weight based on the solid content weight of the charge control agent. Agent.   The liquid developer according to claim 1, wherein the core particles have an average particle diameter of 0.01 to 10 μm.   5. The liquid according to claim 1, wherein the charge control agent is at least one selected from the group consisting of a metal soap, a surfactant, a metal complex, and a metal alkoxide. Developer. 6. The liquid developer according to claim 1, wherein the thermoplastic resin fine particles have an average particle diameter of 0.1 to 5 μm.   The liquid developer according to any one of claims 1 to 6, wherein the thermoplastic resin fine particles have a weight of 1 to 20% by weight based on a weight of the core particles.

Images