KR20050075222A - Liquid ink composition containing cyan pigment - Google Patents

Abstract

It provides a liquid ink composition. The liquid ink composition may comprise a carrier liquid; Organosol particles dispersed in the carrier liquid and comprising an organosol core and a steric stabilizer grafted to the organosol core; And a cyan pigment located in the organosol core.

Description

Liquid ink composition containing cyan pigment

The present invention relates to a liquid ink composition, and more particularly to a liquid ink composition containing a cyan pigment.

Liquid inks are widely used for offset, gravure, ink-jet or electrophotographic printing. The electrophotographic apparatus includes a laser printer, a facsimile, a copier, and the like, and in such an electrophotographic apparatus, the liquid ink is also called liquid toner or developer.

In general, electrophotographic printing using liquid ink comprises i) uniformly charging the surface of the photoconductor, ii) partially exposing the charged surface of the photoconductor to provide discharge and charging regions on the surface of the photoconductor. Forming an electrostatic latent image, i) toner image on the photosensitive member by bringing the photosensitive member on which the electrostatic latent image is formed to a liquid ink, i.e., a developing roller in which liquid toner is discharged onto a surface; And (iii) transferring the toner image formed on the photosensitive member to a recording sheet, and v) cleaning the liquid ink remaining on the photosensitive member after the transferring step.

On the other hand, liquid ink includes ink particles and an insulating liquid called a carrier liquid, which are particles which form the toner image by electrical attraction with an electrostatic latent image formed on the photosensitive member as charged particles. Such ink particles generally consist of colorants and polymer binders.

The liquid ink may be divided into a plastisol ink and an organosol ink according to the type of the polymer binder. The organosol ink contains organosol particles dispersed in the carrier liquid. The organosol particles include an organosol core made of a thermoplastic resin and a steric stabilizer grafted to the organosol core, so that the organosol particles are not aggregated in the carrier liquid and are stericly stabilized. The coloring agent is bonded to the surface of the organosol particles to form ink particles. U.S. Patent Nos. 4,925,766 and 4,978,598 disclose liquid electrophotographic toners and methods for preparing liquid electrophotographic toners comprising such organosols.

The organosol ink has an advantage of obtaining a high-resolution image, but the organosol particles contained in the organosol ink lack the affinity with the colorant and other additives, that is, the binding force, so that the organosol ink is actually used. Can cause many problems. In detail, the organosol ink contains a large amount of a coloring agent that cannot be combined with the organosol particles and is present alone. The coloring agent that is present alone is very small in particle size, and thus it is not easy to control it electrically. Therefore, the colorant may be attached to the non-image area on the photosensitive member, and the colorant attached to the non-image area may be transferred to a recording medium to provide an unclear image. In addition, in the cleaning step of removing the liquid ink remaining on the photoconductor after the transfer step, the colorant having a small particle size may not be sufficiently removed from the photoconductor surface to contaminate the photoconductor. This phenomenon is particularly true for cyan pigments having poor binding properties with the organosol particles.

The technical problem to be achieved by the present invention is to solve the above problems of the prior art, by improving the binding properties of the organosol particles and cyan pigment to increase the average particle diameter of the particles present in the liquid ink, providing a clear image In addition, to provide a liquid ink composition that can reduce the contamination of the photosensitive member surface.

In order to achieve the above technical problem, the present invention provides a liquid ink composition. The liquid ink composition may comprise a carrier liquid; Organosol particles dispersed in the carrier liquid and comprising an organosol core and a steric stabilizer grafted to the organosol core; And a cyan pigment located in the organosol core.

It is preferable that the cyan pigment is phthalocyanine blue whose primary crystal shape is alpha type. Furthermore, the alpha phthalocyanine blue may be a color index (C.I.) PB15: 1 or PB15: 2. The color index PB15: 2 is a group consisting of Hostaperm Blue series (Clarant), Fastogen blue series (DIC), and Sunfast Blue series (Sun Chemical). It may be one pigment selected from.

It is preferable that the liquid ink composition further includes a charge control agent.

Hereinafter, preferred embodiments of the present invention will be described in detail in order to describe the present invention in more detail. However, the present invention is not limited to the embodiments described herein but may be embodied in other forms.

Liquid ink composition according to an embodiment of the present invention is a carrier liquid; Organosol particles dispersed in the carrier liquid and comprising an organosol core and a steric stabilizer grafted to the organosol core; And a cyan pigment located in the organosol core.

The carrier liquid is generally a lipophilic, chemically stable, insulating liquid. In order for the carrier liquid to have insulation, the dielectric constant of the carrier liquid is 5 or less, and the electrical resistivity is 10 ⁹ Ω / cm or more. In addition, the carrier liquid should not be viscous under operating temperature so that the charged particles can be easily moved during the development process, can be properly removed from the substrate on which the final image is formed, and the materials or components used in the electrophotographic apparatus In particular, it should be chemically inert to the photoreceptor surface.

The carrier liquid is aliphatic hydrocarbons such as n-pentane, hexane and heptane, cyclic hydrocarbons such as cyclopentane and cyclohexane, aromatic hydrocarbons such as benzene, toluene and xylene, halogenated alkanes, fluorinated alkanes and fluorocarbons Hydrocarbons, silicone oils and waxes, vegetable oils and waxes, animal oils and waxes, petroleum waxes, mineral waxes, polyethylene waxes, branched paraffinic waxes and oils, stearic acid amides, or mixtures thereof It may be, but is not limited thereto.

The organosol core comprises a unit derived from a polymerizable monomer for organosol core, wherein the polymerizable monomer for organosol core is a (meth) acrylate having a (meth) acrylate-based monomer, an aliphatic or aromatic substituted amino group. Selected from the group consisting of a monomer containing a monomer, a nitrogen-containing heterocyclic substituted vinyl monomer, an N-vinyl substituted cyclic amide monomer, an acrylamide monomer, an aromatic substituted ethylene monomer containing an amino group, and a nitrogen-containing vinyl ether monomer It may be more than one.

The (meth) acrylate monomer may be at least one selected from the group consisting of methyl (meth) acrylate, ethyl (meth) acrylate and butyl (meth) acrylate. The (meth) acrylate-based monomer having an aliphatic or aromatic substituted amino group is N, N-dimethylaminoethyl (meth) acrylate, N, N-diethylaminoethyl (meth) acrylate, N, N-dibutyl Aminoethyl (meth) acrylate, N, N-hydroxyethylaminoethyl (meth) acrylate, N, N-benzylethylaminoethyl (meth) acrylate, N, N-dibenzylaminoethyl (meth) acrylate And it may be one or more selected from the group consisting of N, N-dihexylaminoethyl (meth) acrylate. The nitrogen-containing heterocyclic substituted vinyl-based monomers are N-vinylimidazole, N-vinylindazole, N-vinyltetrazole, 2-vinylpyridine, 4-vinylpyridine, 2-methyl-5-vinylpyridine, 2 At least one selected from the group consisting of -vinylquinoline, 4-vinylquinoline, 2-vinylpyrazine, 2-vinyloxazole and 2-vinyl-benzoxazole. The N-vinyl substituted ring-like amide monomers may be at least one selected from the group consisting of N-vinylpyrrolidone, N-vinylpiperidone, and N-vinyloxazolidone. Can be. The acrylamide monomers include N-methyl acrylamide, N-octyl acrylamide, N-phenyl methacrylamide, N-cyclohexyl acrylamide, N-phenylethyl acrylamide, Np-methoxy-phenylacrylamide, and acrylamide. , N, N-dimethylacrylamide, N, N-dibutylacrylamide and N, N-methylphenylacrylamide. The aromatic substituted ethylene monomer containing the amino group may be at least one selected from the group consisting of dimethylaminostyrene, diethylaminostyrene, diethylaminomethylstyrene, and dioctylaminostyrene. The nitrogen-containing vinyl ether monomers include vinyl-N-ethyl-N-phenylaminoethyl ether, vinyl-N-butyl-N-phenylaminoethyl ether, triethanolamine divinyl ether, vinyldiphenylaminoethyl ether, vinylpyrroli It may be at least one selected from the group consisting of vaginal amino ether, vinyl-beta-morpholinoethyl ether, N-vinylhydroxyethylbenzamide and m-aminophenylvinyl ether. However, the polymerizable monomer for organosol cores is not limited thereto.

The steric stabilizer graft-bonded to the organosol core is a polymer of a C6-C30 (meth) acrylate monomer that is a polymerizable monomer for steric stabilizer formation. The (meth) acrylate monomers of 6 to 30 are hexyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, decyl (meth) acrylate, dodecyl (meth) acrylate, octadecyl (meth) It may be one or more selected from the group consisting of acrylate, behenyl (meth) acrylate (behenyl (meth) acrylate), and isobornyl (meth) acrylate (isobornyl (meth) acrylate), but is not limited thereto.

Preferably, the steric stabilizer is a copolymer of 3,3,5-trimethylcyclohexyl methacrylate (TCHMA) with at least one of the (meth) acrylate monomers having 6 to 30 carbon atoms.

Grafting the steric stabilizer to the organosol core may comprise random grafting of multifunctional free radicals; Ring-open polymerization of cyclic ethers, ester amides or acetals; Epoxidation; Reaction of a hydroxy or amino chain transfer agent with a terminal unsaturated terminal group; Esterification reaction such as glycidyl methacrylate esterifying with methacrylic acid under a tertiary amine catalyst; And other grafting methods including condensation polymerization and known to those skilled in the art.

The organosol core is insoluble in the carrier liquid as a thermoplastic polymer. On the other hand, the steric stabilizer graft-bonded to the organosol core has solubility or limited insolubility in the carrier liquid. Thus, the organosol particles comprising the organosol core and the steric stabilizer can be stably dispersed without aggregation or sedimentation in the carrier liquid.

A cyan pigment is located in the organosol core. The cyan pigment is a pigment exhibiting a cyan color as one of the colorants, and has a poor bonding property with the organosol particles. However, by placing the cyan pigment in the organosol core as described above, the binding force between the organosol particles and the cyan pigment can be improved. As a result, the number of cyan pigments which cannot be combined with the organosol particles and separated by itself can be reduced. As a result, by increasing the average particle diameter in the liquid ink composition and facilitating the electrical control of the cyan pigment, not only can the printed image quality be improved, but also the contamination of the photoreceptor surface can be reduced.

The cyan pigment preferably has 10 to 50% by weight based on the organosol. If the cyan pigment is less than 10% by weight, the printed image may not be clear and blurred, that is, optical density (OD) may be lowered. On the other hand, when the cyan pigment is more than 50% by weight, the dispersion stability is reduced, so that the pigment is agglomerated easily during storage of the ink, and the fixability to the recording medium may be reduced during the printing process.

The cyan pigment is preferably phthalocyanine blue which not only has excellent lightfastness but also shows a clean and pure color. The phthalocyanine blue has a primary crystal shape (primary particle shape) of the alpha type and beta type, and among these, the main crystalline phase of alpha phthalocyanine blue is preferable. The reason for this is that the alpha type is in tablet form, and it is easy to locate the organosol core with respect to the beta type. More specifically, the beta form is in the form of a needle, and even if placed inside the organosol core, it is easy to escape from the organosol core over time due to its pointed shape, whereas the alpha type is not.

The alpha phthalocyanine blue may have a color index (C.I.) PB15: 1 or PB15: 2. Furthermore, the color index PB15: 2 is Hostaperm Blue series (Clarant), Fastogen blue series (DIC) and Sunfast Blue series (Sunfast Blue) It may be one pigment selected from the group consisting of. The Hosta Ferrum Blue series includes Hosta Ferrum Blue AFL, Hosta Ferrum Blue BT-627-D, and the Pathogen Blue Series includes Pathogen Blue BRF, Pathogen Blue RS, Pathogen Blue RSK, and Pathogen Blue. SB765 and the like. The sunfast blue series includes sunfast blue 15: 2 and the like.

The liquid ink composition preferably further includes a charge control agent (CCA). The charge control agent provides a uniform charge polarity to the particles contained in the liquid ink composition, more particularly to the organosol particles to which the cyan pigment is bound.

The charge control agent may be introduced in the form of a metal salt composed of polyvalent metal ions and organic anions as counter ions. These metal ions are Ba (II), Ca (II), Mn (II), Zn (II), Zr (IV), Cu (II), Al (III), Cr (III), Fe (II), Fe (III), Sb (III), Bi (III), Co (II), La (III), Pb (II), Mg (II), Mo (III), Ni (II), Ag (I), Sr (II), Sn (IV), V (V), Y (III) or Ti (IV). The organic anion may be a carboxylate derived from aliphatic or aromatic carboxylic acid, a sulfonate derived from aliphatic or aromatic sulfonic acid.

Preferably, the charge control agent is a cationic charge control agent, and is a metal carboxylate (soap, soaps) disclosed in US Pat. No. 3,411,936. The metal carboxylates are alkaline earth metals and heavy metal salts of fatty acids having at least 6 to 7 carbon atoms, and in particular, zirconium soap of octanoic acid (Zirconium HEXCEM, Mooney Chemicals) is preferable.

Method for producing a liquid ink composition according to an embodiment of the present invention is as follows.

First, a carrier liquid, an acrylic monomer having 6 to 30 carbon atoms, which is a polymerizable monomer for forming a steric stabilizer, and a polymerization initiator are mixed and polymerized to obtain a steric stabilizer. The carrier liquid and the polymerizable monomer for forming a steric stabilizer are as described above.

 In mixing the carrier liquid, the acrylic monomer having 6 to 30 carbon atoms and the polymerization initiator, it is preferable to further add and mix 3,3,5-trimethylcyclohexyl methacrylate (TCHMA). Thereby, the steric stabilizer which is a copolymer of the said 3,3, 5- trimethyl cyclohexyl methacrylate (TCHMA) and the said C6-C30 (meth) acrylate type monomer can be obtained.

The polymerization initiator is to radically decompose by heat or reducing material to further polymerize the monomer. The polymerization initiator may be a water-soluble or fat-soluble persulfate, a peroxide, an azobis compound, or the like. Specifically, the polymerization initiator may be potassium persulfate, ammonium persulfate, t-butylhydroperoxide, hydrogen peroxide, azobisisobutyronitrile (AIBN), long gallite, meta sodium bisulfite, or the like. As the polymerization initiator, any one of the compounds exemplified above may be selected and used alone, or two or more types may be selected and mixed. Transition metal ions may be used together as desired as the polymerization initiator, and the transition metal ions are preferably iron (II) sulfate, copper chloride (II), iron chloride (II), etc., but are not limited thereto.

Subsequently, the steric stabilizer, the carrier liquid, the polymerizable monomer for organosol core and the polymerization initiator are mixed and polymerized to form an organosol. The polymerizable monomer for organosol core is as described above.

In the polymerization process, the polymerizable monomer for organosol cores forms a polymer or copolymer, and the polymer continues to grow so that its molecular weight reaches a critical molecular weight. Polymers that reach the critical molecular weight will fall out of solubility limits, causing precipitation in solution to form organosol cores. Thereafter, the steric stabilizer is graft-bonded to the organosol core and maintained as a whole with the organosol core. The organosol core continues to grow until the polymerizable monomer for organosol core is exhausted, and at this time, the steric stabilizer graft-bonded to the organosol core is stabilized in three dimensions without aggregation of the organosol core. do. As a result, the organosol particles having the organosol core and the steric stabilizer graft-bonded to the organosol core form an organosol stably dispersed in the carrier liquid.

Grafting the steric stabilizer to the organosol core may comprise random grafting of multifunctional free radicals; Ring-open polymerization of cyclic ethers, ester amides or acetals; Epoxidation; Reaction of a hydroxy or amino chain transfer agent with a terminal unsaturated terminal group; Esterification reaction such as glycidyl methacrylate esterifying with methacrylic acid under a tertiary amine catalyst; And other grafting methods including condensation polymerization and known to those skilled in the art.

The organosol, cyan pigment and carrier liquid are then placed in a milling vessel and milled at a temperature above the glass transition temperature of the organosol core. Thereafter, a charge control agent is further added, which is then added to the glass transition temperature of the organosol core. The liquid ink composition is prepared by milling below. Alternatively, the liquid ink composition may be prepared by placing the organosol, cyan pigment, carrier liquid, and charge control agent in a milling vessel, and milling at a temperature above the glass transition temperature of the organosol core.

In general, the glass transition temperature (Tg) refers to the temperature at which metastable non-equilibrium occurs to freeze the micro brown motion of an atom or molecule. The glass transition temperature is found in many polymer materials, and the specific volume, expansion coefficient, specific heat, and the like of the polymer material exhibit a sudden change in the vicinity of the glass transition temperature. More specifically, it exhibits flexible and elastic-rich rubber elastic properties at temperatures above the glass transition temperature, but hardens at temperatures below the glass transition temperature.

Therefore, above the glass transition temperature of the organosol core, the polymer forming the organosol core may be in a state in which the mobility is improved and swelling by the carrier liquid becomes easy. As a result, as described above, by milling above the glass transition temperature of the organosol core, the cyan pigment easily enters into the swollen organosol core and physically bonds. In addition, the cyan pigment entered into the organosol core may be chemically bonded to the polymer forming the organosol core. Therefore, the binding force of the cyan pigment and the organosol particles can be improved.

On the other hand, the cyan pigment is a pigment exhibiting a cyan color as one of the colorant, there is a poor bond to the organosol particles. However, as described above, by improving the binding force between the organosol particles and the cyan pigment, it is possible to reduce the number of cyan pigments that cannot be combined with the organosol particles alone and are separated. This can increase the average particle diameter in the liquid ink composition and facilitate the electrical control of the cyan pigment, thereby improving the print image quality as well as reducing contamination of the photoreceptor surface.

The cyan pigment is preferably phthalocyanine blue which not only has excellent lightfastness but also shows a clean and pure color. The phthalocyanine blue has a primary crystal shape (primary particle shape) of the alpha type and beta type, and among these, the main crystalline phase of alpha phthalocyanine blue is preferable. The reason is that the beta form is in the form of a needle, and even though it is located inside the organosol core by the milling method described above, it is easy to escape from the organosol core due to its pointed shape. On the other hand, the alpha form is a tablet (tablet), it is easy to maintain it after being placed inside the organosol core by the milling method as described above.

The alpha phthalocyanine blue may have a color index (C.I.) PB15: 1 or PB15: 2. Furthermore, the color index PB15: 2 is Hostaperm Blue series (Clarant), Fastogen blue series (DIC) and Sunfast Blue series (Sunfast Blue) It may be one pigment selected from the group consisting of. The Hosta Ferrum Blue series includes Hosta Ferrum Blue AFL, Hosta Ferrum Blue BT-627-D, and the Pathogen Blue Series includes Pathogen Blue BRF, Pathogen Blue RS, Pathogen Blue RSK, and Pathogen Blue. SB765 and the like. The sunfast blue series includes sunfast blue 15: 2 and the like.

The detailed description of the charge control agent is as described above.

Hereinafter, preferred examples are provided to aid in understanding the present invention. However, the following examples are merely to aid the understanding of the present invention, and the present invention is not limited to the following examples.

Production Example; preparation example>

Preparation of Organosol

2560 g of Norpar 12 (Exxon), a carrier liquid, 27 g of 2-hydroxyethyl methacrylate, a polymerizable monomer for steric stabilizer formation, 876 g of 3,3,5-trimethylcyclohexyl methacrylate (TCHMA), and As a polymerization initiator, 8 g of V601 (Wako chem., Japan) which is dimethyl 2,2'-azobis (2-methylpropionate), was mixed, and 70 It stirred at 250 rpm under nitrogen gas atmosphere. Subsequently, the stirred mixture was reacted for 16 hours while stirring at a speed of 250 rpm at 90 ° C.

14 g of dibutyltin dilaurate (DBTDL, Aldrich Chemical Co.) and 41 g of 3-isopropenyl dimethylbenzyl isocyanate (TMI, CYTEC Industries) were added to the reaction mixture, which was then 250 rpm under 70 ° C. and a nitrogen gas atmosphere. The reaction was carried out for 6 hours while stirring at a rate of to give a steric stabilizer.

240 g of the steric stabilizer, 2750 g of norpar 15, 495 g of ethyl methacrylate, and 8 g of V601 (Wako chem. Japan) as a polymerization initiator were mixed, followed by stirring at 75 ° C. under a nitrogen gas atmosphere at a speed of 250 rpm. The reaction was completed for a period of time to complete the organosol. The glass transition temperature of the thus prepared organosol is about 65 ° C.

Preparation of Liquid Ink Compositions

646 g of the organosol, 33 g of Norpar 12 (Exxon) as a carrier liquid, 14 g of color index (CI) PB as a cyan pigment, and 14 g of zirconium hexium (Zr-HEXCEM, 2.4% solution) as a charge control agent; Mooney Chemicals G) After putting 7g into the milling vessel, 1400g of zirconium beads (zirconium beads) was put, and milled with stirring at 80 ° C. at 5000 rpm for 2 hours. The liquid milled at 80 ° C. was then cooled to 42 ° C. and milled at 42 ° C. at a speed of 5000 rpm for 30 minutes to prepare a liquid ink composition containing cyan pigment having a color index PB 15: 2.

<Comparative Example 1; comparative example 1>

Preparation of Liquid Ink Compositions

646 g of organosol prepared in the same manner as the organosol in the above preparation, 33 g of Norpar 12 (Exxon) as a carrier liquid, 14 g of color index (CI) PB 15: 2 as cyan pigment, and zirconium hexium as a charge control agent (Zr-HEXCEM, 2.4% solution; Mooney Chemicals) 7g was put in a milling vessel, 1400g of zirconium beads (zirconium beads), and milled for 2 hours 30 minutes at a speed of 5000rpm at 42 ℃, color index PB 15 A liquid ink composition containing cyan pigment of 2: was prepared.

<Comparative Example 2; comparative example 2>

Preparation of Liquid Ink Compositions

Organosol 646g prepared in the same manner as the organosol in the preparation example, 33g Norpar 12 (Exxon) as a carrier liquid, 14g color index (CI) PB 15: 4 as a cyan pigment and zirconium hexium as a charge control agent 7 g (Zr-HEXCEM, 2.4% solution; Mooney Chemicals) was put in a milling vessel, 1400 g of zirconium beads were added, and the mixture was milled while stirring at 80 ° C. at 5000 rpm for 2 hours. The liquid milled at 80 ° C. was then cooled to 42 ° C. and milled at 42 ° C. for 30 minutes at a speed of 5000 rpm to prepare a liquid ink composition containing cyan pigment of color index PB 15: 4.

The particle size of the ink particles contained in the liquid preparations prepared in Preparation Examples and Comparative Examples 1 and 2 was measured using Horiba 910. The measurement results are shown in Table 1.

result Volume average particle diameter (µm) Number average particle diameter (㎛) (Volume average particle diameter) / (number average particle diameter) Fraction (%) with a volume average particle diameter of 1 μm Production Example 5.66 1.1 5.15 1.9 Comparative Example 1 5.34 0.46 11.61 2.5 Comparative Example 2 5.69 0.2 28.45 2.7

Referring to Table 1, although the volume average particle diameter is similar to that of Comparative Example 1 in the case of the preparation example, the number average particle diameter is much larger. In addition, in the case of the production example, the value of (volume average particle diameter) / (number average particle diameter) is very small as compared with the case of Comparative Example 1. In particular, in the case of the production example, it can be seen that the fraction having a volume average particle diameter of 1 μm or less is significantly reduced compared with the case of Comparative Example 1. As a result, in the case of the liquid ink composition prepared according to the above preparation example, it can be seen that not only the average particle diameter is large, but also the distribution range of the particle diameter is narrow. In preparing the liquid ink composition, it is expected that milling at a glass transition temperature of the organosol core above the cyan pigment, that is, a result of improving the binding force between the alpha-type phthalocyanine blue and the organosol particles.

On the other hand, in the case of the production example, the volume average particle diameter is similar to that of Comparative Example 2, but the number average particle diameter is much larger. In addition, in the case of the production example, the value of (volume average particle diameter) / (number average particle diameter) is very small as compared with the case of Comparative Example 2. In particular, in the case of the production example, it can be seen that the fraction having a volume average particle diameter of 1 μm or less is significantly reduced compared to the case of the comparative example. As a result, in the case of the liquid ink composition prepared according to the above preparation example, it can be seen that not only the average particle diameter is large, but also the distribution range of the particle diameter is narrow. This is because the color index PB 15: 4 (Comparative Example 2) is not continuously located inside the organosol core because its main crystal phase is beta-shaped and needle-shaped, while the color index PB 15: 2 (Preparation Example) ) Is expected to be due to its main crystalline phase being in alpha form tablet form so that it can be continuously placed inside the organosol core.

1A and 1B are photographs of the photoconductor surface after driving a laser printer using the liquid ink compositions according to Preparation Example and Comparative Example 2, respectively. 1A and 1B, reference numeral A denotes a photoconductor, and reference numeral B denotes contamination of the photoconductor surface.

Referring to FIGS. 1A and 1B, in the case of FIG. 1A, the contamination of the surface of the photoreceptor may be lower than that of FIG. 1B. This is because the comparative example 2 has a large number of pigments that are present alone in the liquid ink composition, whereas in the preparation examples, the number of pigments that are present alone in the liquid ink composition is small.

 2A and 2B are graphs of the potentials of the photoconductor surfaces after driving a laser printer using the liquid ink compositions according to Preparation Example and Comparative Example 2, respectively.

2A and 2B, in the case of the manufacturing example, the charging potential of the photosensitive member surface is 930 ㅁ 20V, whereas in the comparative example 2, the charging potential of the photosensitive member surface is 750 ㅁ 80 V, and in the case of Comparative Example 2 It can be seen that the noise of the charge potential is severe. This is presumably due to contamination of the photoreceptor surface as confirmed in FIG.

According to the present invention as described above, by increasing the binding force of the cyan pigment and the organosol particles, it is possible to increase the particle diameter in the liquid ink composition and to narrow the distribution range of the particle diameter. As a result, it is possible not only to provide a clear image but also to reduce contamination of the photoreceptor surface.

1A and 1B are photographs of the photoconductor surface after driving a laser printer using the liquid ink compositions according to Preparation Example and Comparative Example 2, respectively.

2A and 2B are graphs of the potentials of the photoconductor surfaces after driving a laser printer using the liquid ink compositions according to Preparation Example and Comparative Example 2, respectively.

Claims (9)

Carrier liquids; Organosol particles dispersed in the carrier liquid and comprising an organosol core and a steric stabilizer grafted to the organosol core; And And a cyan pigment located in the organosol core. The method of claim 1, The cyan pigment is a liquid ink composition, characterized in that the primary crystalline phase (primary particle shape) is phthalocyanine blue alpha. The method of claim 2, The alpha type phthalocyanine blue has a color index (C.I.) of PB15: 1 or PB15: 2. The method of claim 1, The organosol core may be a (meth) acrylate monomer, a (meth) acrylate monomer having an aliphatic or aromatic substituted amino group, a nitrogen-containing heterocyclic substituted vinyl monomer, an N-vinyl substituted cyclic amide monomer, Liquid ink composition comprising units derived from at least one polymerizable monomer for organosol cores selected from the group consisting of acrylamide monomers, aromatic substituted ethylene monomers containing amino groups and nitrogen-containing vinyl ether monomers . The method of claim 1, The steric stabilizer is a liquid ink composition having 6 to 30 carbon atoms of a (meth) acrylate monomer. The method of claim 5, The (meth) acrylate monomers having 6 to 30 carbon atoms include hexyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, decyl (meth) acrylate, dodecyl (meth) acrylate, and octadecyl (meth). A liquid ink composition, characterized in that at least one selected from the group consisting of: acrylate, behenyl (meth) acrylate (behenyl (meth) acrylate), and isobornyl (meth) acrylate. The method of claim 5, The steric stabilizer is a liquid ink composition, characterized in that a copolymer of 3,3,5-trimethylcyclohexyl methacrylate (TCHMA) with at least one of the (meth) acrylate monomers having 6 to 30 carbon atoms. The method of claim 1, A liquid ink composition, further comprising a charge control agent. The method of claim 1, The charge control agent is Ba (II), Ca (II), Mn (II), Zn (II), Zr (IV), Cu (II), Al (III), Cr (III), Fe (II), Fe (III), Sb (III), Bi (III), Co (II), La (III), Pb (II), Mg (II), Mo (III), Ni (II), Ag (I), Sr From carboxylates and aromatic carboxylic acids derived from aliphatic carboxylic acids and one metal ion selected from the group consisting of (II), Sn (IV), V (V), Y (III) and Ti (IV) A liquid ink composition, characterized in that it is one organic anion selected from the group consisting of carboxylates derived, sulfonates derived from aliphatic sulfonic acids and sulfonates derived from aromatic sulfonic acids.