JP2019090971A - Liquid developer - Google Patents

Abstract

To provide a liquid developer excellent in adhesion of an image to be fixed to a resin film, and a printing method using the liquid developer.SOLUTION: There is provided a liquid developer that contains toner particles containing a binder resin and a colorant, a dispersant, and an insulating liquid, wherein the binder resin is a polycondensate of a carboxylic acid component containing a polymerized fatty acid and an amine component, and contains a polyamide resin having a storage elastic modulus at 25°C of 2.0×10Pa or less, the liquid developer containing toner particles containing a binder resin and a colorant, a dispersant, and an insulating liquid, wherein when the binder resin is made into a film and adhered to a film selected from a polyester film and a polypropylene film in conformance with JIS K 6854-3:1999, the maximum peel strength of the binder resin is 0.5 N or more and 10 N or less in terms of 15 mm width. Also provided is a printing method using the liquid developer.SELECTED DRAWING: None

Description

  The present invention relates to a liquid developer used for developing a latent image formed in, for example, electrophotography, electrostatic recording, electrostatic printing and the like, and a printing method using the liquid developer.

  Examples of the electrophotographic developer include a dry developer using toner particles made of a material containing a colorant and a binder resin in a dry state, and a liquid developer in which toner particles are dispersed in an insulating liquid.

  As is well known, the liquid developer is one in which toner particles are dispersed in an electrically insulating organic liquid, and the toner particles need to be colored, charged, fixed and dispersed. , Colorants, resins, and other additives. In a liquid development process, toner particles are usually charged to the opposite polarity to the electrostatic latent image charge, and these toner particles are attracted to the latent image charge in the electrically insulating liquid and are transferred to the latent image by electrophoresis and latent Development is carried out selectively adhering to the image.

  In the printing material currently put into practical use in the process of using a liquid developer, a material such as plain paper that easily penetrates is often used. When such a printing medium is used, the toner adhesion property is obtained to such an extent that toner particles penetrate into paper fibers, and therefore, a fixing process using a heat heat roll or the like is often not used. However, in recent years, printing materials have also become diverse, and coated paper and plastic films that are difficult for liquid to penetrate, and metal plates etc. have become the subject again, the problem of fixing and the problem of adhesion between toner and printing material Is beginning to attract attention.

  The device as described in Patent Document 1, that is, the developed liquid development toner is transferred via the intermediate transfer member without directly transferring from the electrostatic latent image carrier to the printing medium, and the intermediate transfer member An apparatus has been developed in which image distortion does not occur or the transferability of toner is improved by heating the above liquid development toner. In particular, the effect is remarkable in the case of a printing material to which liquid developing toner such as a plastic film does not penetrate and the kind of the printing material is in a direction to be further expanded by the invention of this device.

  Patent Document 2 proposes a liquid developer containing toner particles containing a polymerized fatty acid-modified polyamide resin as a means for improving adhesion to a plastic film, and the film adhesion is improved by a tape peeling test. It has been reported.

Japanese Patent Publication No. 4-507148 JP, 2017-58588, A

  The present invention relates to providing a liquid developer excellent in resin film adhesion of a fixed image and a printing method using the liquid developer.

The present invention
[1] A liquid developer containing toner particles containing a binder resin and a colorant, a dispersant, and an insulating liquid, wherein the binder resin is a polycondensate of a carboxylic acid component containing a polymerized fatty acid and an amine component A liquid developer containing a polyamide resin having a storage elastic modulus at 25 ° C. of 2.0 × 10 ⁸ Pa or less,
[2] A toner developer containing a binder resin and a colorant, a dispersant, and a liquid developer containing an insulating liquid, wherein the binder resin is formed into a film, and polyester according to JIS K 6854-3: 1999. A liquid developer having a maximum peel strength of 0.5 N or more and 10 N or less in terms of a width of 15 mm when adhered to a film selected from a film and a polypropylene film,
[3] A method of printing an image on a resin film using the liquid developer according to the above [1] or [2], wherein the resin film is a polyester film, and [4] the above [1] ] It is a method of printing an image on a resin film using the liquid developer as described in [2], and it is related with the printing method whose said resin film is a polypropylene film.

  The liquid developer of the present invention exhibits an effect of being excellent in resin film adhesion of a fixed image.

The liquid developer of the present invention is a polycondensate of a carboxylic acid component containing a polymerized fatty acid and an amine component as a binder resin for toner particles, and is a polyamide having a storage elastic modulus at 25 ° C. of 2.0 × 10 ⁸ Pa or less. It has one feature in that it contains a resin, and it has excellent adhesion to a resin film.

Although the reason which produces such an effect is not certain, it is considered as follows.
A polyamide resin obtained by using a polymerized fatty acid (hereinafter, also referred to as a polymerized fatty acid modified polyamide resin) has a hydrocarbon group having a relatively large molecular weight derived from the polymerized fatty acid as a soft segment in the molecular structure and an amide bond of high polarity. It is considered to be due to having, but it is a resin having very characteristic properties having both flexibility and adhesiveness. Therefore, the polymerized fatty acid-modified polyamide resin is a polyester film having a polar group, and the adhesiveness is easily obtained, and the polyamide resin having a storage elastic modulus at 25 ° C. of 2.0 × 10 ⁸ Pa or less has few polar groups and has adhesiveness. It is believed that the fixability and adhesion are improved even for inferior polypropylene films, and the image strength and image quality are improved. The adhesive property with the polypropylene film is improved when the storage elastic modulus is 2.0 × 10 ⁸ Pa or less, because the resin becomes soft and the adhesive property is developed, and the followability with the film is considered to be improved. The polymeric fatty acid-modified polyamide resin is classified into two, a thermoplastic system and a reaction system having an amino group, but the polymeric fatty acid-modified polyamide resin in the present invention is preferably a thermoplastic resin.

  The liquid developer of the present invention forms a film of the liquid developer, and when it is adhered to a film selected from a polyester film and a polypropylene film according to JIS K 6854-3: 1999, the maximum peeling strength is 15 mm in width conversion. Preferably, it is 0.5 N or more, more preferably 0.8 N or more, further preferably 1.0 N or more, and preferably 10 N or less, more preferably 7 N or less, still more preferably 5 N or less. As for the maximum peel strength, “when adhered to a film selected from polyester film and polypropylene film” means “when adhered to a polyester film or adhered to a film selected from a polypropylene film” The meaning is The liquid developer of the present invention can also be specified as one having such peel strength with respect to a resin film.

  As described above, the binder resin contains a polymerized fatty acid-modified polyamide resin which is a polycondensate of a carboxylic acid component containing a polymerized fatty acid and an amine component.

  The polymerized fatty acid is not particularly limited. For example, unsaturated fatty acids or dimer fatty acids (dimer acids) of lower alkyl esters thereof (alkyl group having 1 or more and 3 or less carbon atoms) are preferable. Examples of unsaturated fatty acids include oleic acid, linoleic acid, 3-octenoic acid, 10-undecenoic acid, elaidic acid, palmitoleic acid, linolenic acid and the like. The carbon number of the unsaturated fatty acid is preferably 10 or more, more preferably 14 or more, from the viewpoint of flexibility for adhesion, and preferably 24 or less, more preferably 20 or less from the viewpoint of cohesion for adhesion. It is.

  The polymerization method of unsaturated fatty acid is not particularly limited, but a method of polymerizing by heating lower alkyl ester of unsaturated fatty acid to about 300 ° C., a method of thermally polymerizing in the presence of a catalyst such as activated clay or Lewis acid, peroxide And the like.

  The content of the polymerized fatty acid is preferably 70 mol% or more, more preferably 80 mol% or more, still more preferably 85 mol% or more, and further preferably in the carboxylic acid component from the viewpoint of flexibility and adhesiveness with a polypropylene film. Is 90 mol% or more.

  Examples of carboxylic acids other than polymerized fatty acids include aliphatic monocarboxylic acids (monomer acids), aromatic monocarboxylic acids, aliphatic dicarboxylic acids, aromatic dicarboxylic acids and the like, but from the viewpoint of adhesion to resin films, carboxylic acids The acid component preferably further contains an aliphatic monocarboxylic acid, and the carbon number thereof is preferably 3 or more, more preferably 3 or more and 6 or less. The content of the aliphatic monocarboxylic acid is preferably 2 mol% or more, more preferably 4 mol% or more, and preferably 20 mol% or less, more preferably 15 mol% or less, in the carboxylic acid component. Preferably it is 10 mol% or less, More preferably, it is 7 mol% or less.

  The amine component preferably contains ethylenediamine and m-xylenediamine.

  The content of ethylene diamine is preferably 50 mol% or more, more preferably 60 mol% or more from the viewpoint of securing the amide bond concentration in the amine component to improve the strength of the resin and further improving the film adhesion. More preferably, it is 65 mol% or more, and from the viewpoint of improving the flexibility and adhesiveness and further improving the film adhesion, it is preferably 80 mol% or less, more preferably 77 mol% or less, still more preferably 73 It is less than mol%.

  The content of m-xylenediamine is preferably 20 mol% or more, more preferably 23 mol% or more, and still more preferably, from the viewpoint of improving the flexibility and adhesiveness in the amine component and further improving the film adhesion. From the viewpoint of improving the strength of the resin by securing the concentration of the amide bond and being 28 mol% or more, and further improving the film adhesion, it is preferably 50 mol% or less, more preferably 40 mol% or less Preferably it is 35 mol% or less.

  The amine component may contain an amine other than ethylenediamine and m-xylenediamine as long as the effects of the present invention are not impaired. Other amines include diaminophenylmethane, phenylenediamine, triaminobenzene and triamino Examples thereof include aromatic amines such as phenol and tetraaminobenzene, and polyalkylene polyamines such as diethylenetriamine, triethylenetetramine and tetraethylenepentamine.

  The polymerized fatty acid modified polyamide resin is obtained by polycondensing a carboxylic acid component and an amine component in the same manner as an ordinary polyamide resin. The reaction temperature is preferably 160 to 250 ° C., more preferably 180 to 230 ° C. The reaction is preferably carried out in an inert gas, and the reaction may be carried out under reduced pressure. Further, in consideration of the physical properties of the obtained resin, the difference between the carboxy equivalent of the carboxylic acid component and the amine equivalent of the amine component is preferably small.

The adhesiveness to a film improves that the storage elastic modulus at 25 degrees C of a polymeric fatty acid modified polyamide resin is 2.0x10 < ⁸ > Pa or less. Therefore, the storage elastic modulus is 2.0 × 10 ⁸ Pa or less, preferably 1.8 × 10 ⁸ Pa or less, more preferably 1.6 × 10 ⁸ Pa or less, and from the viewpoint of resin strength to maintain adhesion, Preferably it is 1.0 * 10 < ⁶ > Pa or more, More preferably, it is 1.0 * 10 < ⁷ > Pa or more.

  The glass transition temperature of the polymerized fatty acid-modified polyamide resin is preferably 30 ° C. or less, more preferably 20 ° C. or less, still more preferably 15 ° C. or less from the viewpoint of film adhesion, and preferably from the viewpoint of liquid toner production. Is −20 ° C. or higher, more preferably −10 ° C. or higher, and still more preferably 0 ° C. or higher. Although the loss tangent (tan δ) can be obtained from the ratio of the storage elastic modulus and the loss elastic modulus obtained by dynamic viscoelasticity measurement of the polymerized fatty acid-modified polyamide resin, the peak temperature of this loss tangent (tan δ) is the glass transition temperature I assume.

  The loss tangent (tan δ) of the polymerized fatty acid-modified polyamide resin is preferably 0.15 or more, more preferably 0.2 or more, and still more preferably 0.25 or more from the viewpoint of adhesiveness, and 0.4 from the viewpoint of coating film strength. Or less, more preferably 0.35 or less, and still more preferably 0.3 or less.

  The softening point of the polymerized fatty acid modified polyamide resin is preferably 110 ° C. or less, more preferably 105 ° C. or less, still more preferably 100 ° C. or less from the viewpoint of film adhesion, and preferably from the viewpoint of liquid toner production. It is 70 ° C. or more, more preferably 80 ° C. or more.

  The weight average molecular weight of the polymerized fatty acid modified polyamide resin is preferably 3,000 or more, more preferably 5,000 or more, still more preferably 7,000 or more, from the viewpoint of obtaining the cohesion of the resin necessary for film adhesion. From the viewpoint of obtaining sufficient wet adhesion, it is preferably 20,000 or less, more preferably 17,000 or less, and still more preferably 15,000 or less.

  The acid value of the polymerized fatty acid-modified polyamide resin is preferably 25 mg KOH / g or less, more preferably 20 mg KOH / g or less, still more preferably 10 mg KOH / g or less, from the viewpoint of obtaining the cohesion of the resin necessary for adhesiveness. From the viewpoint of obtaining sufficient adhesion to the film due to wetting, it is preferably 0.5 mg KOH / g or more, more preferably 1.0 mg KOH / g or more. From the same point of view, the amine value of the polymerized fatty acid modified polyamide resin is preferably 10 mg KOH / g or less, more preferably 5 mg KOH / g or less, still more preferably 3 mg KOH / g or less, and preferably 0.5 mg KOH / g. The above, more preferably 1 mg KOH / g or more.

  The polymerized fatty acid-modified polyamide resin is formed into a film from the viewpoint of obtaining adhesiveness with the film, and the maximum peel strength when it is adhered to a film selected from a polyester film and a polypropylene film according to JIS K 6854-3: 1999. It is preferably 0.85 N or more, more preferably 1.0 N or more, and preferably 17 N or less, more preferably 10 N or less in terms of 15 mm width.

  The content of the polymerized fatty acid-modified polyamide resin in the binder resin is preferably 90% by mass or more, more preferably 95% by mass or more, and 100% by mass, that is, it is more preferable to use only the polymerized fatty acid-modified polyamide resin as a resin. . In addition, you may contain resin other than polymeric fatty acid modified | denatured polyamide resin in the range which does not impair the effect of this application. As resins other than the polymerized fatty acid modified polyamide resin, for example, other polyamide resin, polyester, polystyrene, styrene-propylene copolymer, styrene-butadiene copolymer, styrene-vinyl chloride copolymer, styrene-vinyl acetate copolymer Styrene resin which is a homopolymer or copolymer containing styrene or a styrene-substituted product such as a combination, styrene-maleic acid copolymer, styrene-acrylic acid ester copolymer, styrene-methacrylic acid ester copolymer, etc. Resin, rosin modified maleic resin, polyethylene resin, polypropylene, polyurethane, silicone resin, phenol resin, aliphatic or alicyclic hydrocarbon resin, etc. may be mentioned, and one or more of them may be used in combination be able to.

  As the colorant, dyes, pigments and the like used as colorants for toners can be used. For example, carbon black, phthalocyanine blue, permanent brown FG, brilliant first scarlet, pigment green B, rhodamine-B base, solvent red 49, solvent red 146, solvent blue 35, quinacridone, carmine 6B, isoindoline, disazo aero etc. may be mentioned. . In the present invention, the toner particles may be either black toner or color toner.

  The content of the colorant is preferably 5 parts by mass or more, more preferably 10 parts by mass or more, still more preferably 15 parts by mass or more, with respect to 100 parts by mass of the binder resin, from the viewpoint of improving the image density. Then, from the viewpoint of improving the pulverizing property of the toner to make the particle diameter small, the viewpoint of improving the low temperature fixing property, and the viewpoint of improving the dispersion stability of the toner particles to improve the storage stability The amount is preferably 100 parts by mass or less, more preferably 70 parts by mass or less, still more preferably 50 parts by mass or less, and still more preferably 30 parts by mass or less.

  In addition to the binder resin and the colorant, the toner particles may be a releasing agent, a charge control agent, a charge control resin, a magnetic powder, a flowability improver, a conductive regulator, a reinforcing filler such as a fibrous substance, and an antioxidant You may contain suitably additives, such as an agent and a cleaning property improvement agent.

  The toner particles are produced by melt-kneading a toner raw material containing a binder resin and a colorant, and pulverizing the obtained melt-kneaded product, an aqueous binder resin dispersion and an aqueous colorant dispersion. Examples thereof include a method of mixing and coalescing binder resin particles and colorant particles, and a method of stirring an aqueous binder resin dispersion liquid and a colorant at high speed. From the viewpoint of improving the developability and the fixability, it is preferable to melt and knead the toner raw material and then pulverize it, preferably by wet pulverization.

  First, it is preferable that toner raw materials containing a binder resin, a coloring agent, an additive used as needed, etc. are mixed in advance by a mixer such as a Henschel mixer, a super mixer, a ball mill or the like and then supplied to a kneader From the viewpoint of improving the dispersibility of the colorant in the binder resin, a Henschel mixer is more preferable.

  The mixing with the Henschel mixer is performed while adjusting the circumferential speed of stirring and the stirring time. The circumferential velocity is preferably 10 m / sec or more and 30 m / sec or less from the viewpoint of improving the dispersibility of the colorant. The stirring time is preferably 1 minute or more and 10 minutes or less from the viewpoint of improving the dispersibility of the colorant.

  Subsequently, melt kneading of the toner raw material can be performed using a known kneader such as a closed kneader, a uniaxial or twin screw kneader, or a continuous open roll kneader.

  Next, after cooling the melt-kneaded product to such an extent that it can be pulverized, toner particles can be obtained through a pulverization process, and if necessary, a classification process and the like.

  The grinding process may be divided into multiple stages. For example, the melt-kneaded product may be roughly pulverized to about 1 to 5 mm and then finely pulverized. Moreover, in order to improve the productivity at the time of a grinding | pulverization process, you may grind | pulverize, after mixing a melt-kneaded thing with inorganic fine particles, such as hydrophobic silica.

  The grinder used in the grinding step is not particularly limited, and examples of the grinder suitably used in the coarse grinding include an atomizer and a rotoplex, but a hammer mill may be used. Moreover, as a pulverizer suitably used for pulverization, a fluidized bed jet mill, an air jet mill, a mechanical mill and the like can be mentioned.

  Examples of classifiers used in the classification process include pneumatic classifiers, inertial classifiers, and sieve classifiers. In addition, you may repeat a grinding process and a classification process as needed.

The volume median particle diameter (D ₅₀ ) of the toner particles obtained in the pulverizing step and the classification step as needed is preferably 3 μm or more, more preferably from the viewpoint of improving the productivity of the wet pulverizing step described later. 4 μm or more, and preferably 15 μm or less, more preferably 12 μm or less. The volume median particle size (D ₅₀ ) means a particle size at which the cumulative volume frequency calculated by volume fraction is 50% as calculated from the smaller particle size. The toner particles are preferably further pulverized by wet grinding or the like after being mixed with the dispersant and the insulating liquid.

  The content of the toner particles is preferably 10 parts by mass or more, more preferably 20 parts by mass or more, still more preferably 30 parts by mass or more from the viewpoint of high-speed printability with respect to 100 parts by mass of the insulating liquid From the viewpoint of improving the dispersion stability, it is preferably 100 parts by mass or less, more preferably 80 parts by mass or less, still more preferably 70 parts by mass or less, and still more preferably 60 parts by mass or less.

The liquid developer of the present invention is dispersed from the viewpoint of improving the dispersion stability of the toner particles and improving the storage stability, and from the viewpoint of improving the pulverizing property of the toner particles at the time of wet pulverization to obtain a small particle diameter liquid developer. Contains an agent. The dispersant is used to stably disperse toner particles in the insulating liquid. The liquid developer of the present invention preferably contains a basic dispersant having a basic adsorptive group from the viewpoint of improving the adsorptivity to the polymerized fatty acid modified polyamide resin. As a basic adsorptive group, an amino group (-NH ₂ , -NHR, -NHRR '), an imino group (= NH), an amido group (-C (= O) -NRR', from the viewpoint of the positive chargeability of the toner. ), Imide group (-N (COR) ₂ ), nitro group (-NO ₂ ), cyano group (-CN), azo group (-N = N-), diazo group (= N ₂ ), and azide group ( At least one nitrogen-containing group selected from the group consisting of -N ₃ ) is preferred. Here, R and R 'represent a C1-C5 hydrocarbon group. From the viewpoint of the adsorptivity of the dispersant to the toner particles, an amino group or an imino group is preferable, from the viewpoint of enhancing the adsorption efficiency of the dispersant, and from the viewpoint of suppressing the aggregation of the toner particles and reducing the viscosity of the liquid developer. An imino group is more preferred. The basic dispersant preferably has a plurality of basic adsorptive groups, and as the basic dispersant having an imino group, a dehydrated condensate of a polyimine and a carboxylic acid, or a polyimine and a maleic anhydride-modified polyalkylene Preferred are dehydrated condensates of the compounds.

  As the polyimine, a polyalkyleneimine is preferred from the viewpoint of improving the dispersion stability of the toner particles and improving the storage stability. Specific examples thereof include polyethylene imine, polypropylene imine, and polybutylene imine. However, polyethylene imine is more preferable from the viewpoint of improving the dispersion stability of the toner particles and improving the storage stability. The addition mole number of ethyleneimine is preferably 10 or more, more preferably 100 or more, and preferably 1,000 or less, more preferably 500 or less.

  On the other hand, the carboxylic acid is preferably 10 to 30 carbon atoms, more preferably 12 to 24 carbon atoms, and still more preferably 16 carbon atoms, from the viewpoint of improving the dispersion stability of the toner particles and improving storage stability. A saturated or unsaturated aliphatic carboxylic acid having a molecular weight of 22 or less is preferable, and a linear saturated or unsaturated aliphatic carboxylic acid is more preferable. Specific examples of carboxylic acids include linear saturated aliphatic carboxylic acids such as lauric acid, myristic acid, palmitic acid and stearic acid; and linear unsaturated aliphatic carboxylic acids such as oleic acid, linoleic acid and linolenic acid. Be

  The carboxylic acid may also have a substituent such as a hydroxy group. From the viewpoint of improving the dispersion stability of the toner particles and improving the storage stability, hydroxycarboxylic acids having a hydroxy group as a substituent are preferred. Examples of hydroxycarboxylic acids include hydroxycarboxylic acids such as mevalonic acid, ricinoleic acid and 12-hydroxystearic acid. The hydroxycarboxylic acid may be a condensate thereof.

  From the above point of view, the carboxylic acid is preferably a hydroxy aliphatic carboxylic acid having preferably 10 to 30 carbon atoms, more preferably 12 to 24 carbon atoms, and still more preferably 16 to 22 carbon atoms, or a condensate thereof More preferred is 12-hydroxystearic acid or a condensate thereof.

  As a commercial product of dehydrated condensation product of polyimine and carboxylic acid, Solsparse 11200 (Amine value in 100% conversion: 64 mg KOH / g), Solsparse 13940 (Amine value in 100% conversion: 130 mg KOH / g) (above, In all cases, Nippon Lubrizol Co., Ltd.) and the like can be mentioned, and Solsparse 11200 is preferable.

  As the maleic anhydride-modified polyalkylene compound, those obtained by reacting maleic anhydride with polyethylene, polypropylene, polyisobutylene having a double bond at the end are used. From the viewpoint of enhancing the dispersion stability of the toner particles and improving the storage stability, the weight average molecular weight of the polyalkylene is preferably 500 or more, more preferably 700 or more, and preferably 2,000 or less, more preferably 1,500. It is below.

  Examples of commercially available products of maleic anhydride-modified polyalkylene compounds include maleic acid-modified propylene homopolymers of Baker Hughes, and polyisobutene succinic anhydrides of Chevron and Dover ChemiCal.

  The weight average molecular weight of the dehydrated condensate of the polyimine and the carboxylic acid and the dehydrated condensate of the polyimine and the maleic anhydride-modified polyalkylene compound is preferably 2,000 or more from the viewpoint of improving the dispersion stability of the toner particles and improving the storage stability. Is more preferably 4,000 or more, still more preferably 8,000 or more, and preferably 50,000 or less, more preferably 40,000 or less, still more preferably 30,000 or less, still more preferably 20,000 or less, from the viewpoint of toner crushability. Is less than 15,000.

  The amine value of the dehydrated condensate of polyimine and carboxylic acid and the amine value of polyimine and maleic anhydride-modified polyalkylene compound are preferably 20 mg KOH / g or more, more preferably from the viewpoint of improving the dispersion stability of the toner particles and improving storage stability. Is 30 mg KOH / g or more, more preferably 40 mg KOH / g or more, still more preferably 50 mg KOH / g or more, and from the viewpoint of improving the developability of the liquid developer, preferably 150 mg KOH / g or less, more preferably 120 mg KOH / g. It is at most g, more preferably at most 100 mg KOH / g.

  The content of the basic dispersant is preferably 0.5 parts by mass or more, more preferably 1 part by mass or more, and still more preferably 2 parts by mass or more with respect to 100 parts by mass of toner particles, from the viewpoint of dispersion stability of the toner particles. And from the viewpoint of the chargeability of the toner, it is preferably 10 parts by mass or less, more preferably 8 parts by mass or less.

  The liquid developer of the present invention may contain known dispersants other than the basic dispersant, but the content of the basic dispersant is preferably 50% by mass or more in the dispersant. More preferably, it is 70% by mass or more, further preferably 90% by mass or more, further preferably 95% by mass or more, and further preferably 100% by mass.

The insulating liquid in the present invention means a liquid in which electricity does not easily flow, but in the present invention, the conductivity of the insulating liquid is preferably 1.0 × 10 ⁻¹¹ S / m or less, more preferably 5.0. It is not more than 10 ^-12 S / m, and preferably not less than 1.0 10 ^-13 S / m.

  Specific examples of the insulating liquid include, for example, aliphatic hydrocarbons, alicyclic hydrocarbons, aromatic hydrocarbons, hydrocarbon solvents such as halogenated hydrocarbons, polysiloxanes, vegetable oils, etc. At least one member selected from the group consisting of solvents and polysiloxanes is preferable. Among them, hydrocarbon solvents are more preferable from the viewpoint of low-temperature fixability, low viscosity, grindability, low-temperature fixability, and resistance Aliphatic hydrocarbons are more preferred because of their excellent balance of abrasiveness. Examples of aliphatic hydrocarbons include paraffinic hydrocarbons and olefins having 12 to 18 carbon atoms. One or two or more of these can be used in combination. Among aliphatic hydrocarbons, paraffin hydrocarbons are preferable from the viewpoints of improving the dispersion stability of toner particles in a liquid developer and improving the low temperature fixability of the liquid developer and the resistance. As paraffinic hydrocarbons, liquid paraffin, isoparaffin and the like can be mentioned.

  Commercial products of aliphatic hydrocarbons include Isopar G, Isopar H, Isopar L, Isopar K, Isopar M (all by ExxonMobil), Shellsol 71, Shellsol TM (all by Shell Chemicals Japan) IP Solvent 1620, IP Solvent 2028, IP Solvent 2835 (all available from Idemitsu Kosan Co., Ltd.), Moresco White P-55, Moresco White P-70, Moresco White P-100, Moresco White P-150, Moresco White P-260 (all manufactured by MORESCO), Cosmo White P-60, Cosmo White P-70 (all manufactured by Cosmo Petroleum Lubricants), Lightol (manufactured by Sonneborn), Isozole 400, Cactus N12D, Cactus N14 (all available from JX Nippon Oil & Energy Corporation), Linearn 14, Linearn 16, Linear 18, Linearen 124, Linearen 148, Linearen 168 (all manufactured by Idemitsu Kosan Co., Ltd.) "NAS-3", "NAS-4", "NAS-5H" (all manufactured by NOF Corporation) Can be mentioned.

  The content of the hydrocarbon solvent in the insulating liquid is preferably 60% by mass or more, more preferably 80% by mass or more, still more preferably 90% by mass or more, still more preferably 95% by mass or more, further preferably 100% by mass %.

  The viscosity at 25 ° C. of the insulating liquid improves the dispersion stability of the toner particles in the liquid developer to improve the storage stability, and the pulverizing property of the toner particles at the time of wet grinding to improve the small particle diameter liquid development From the viewpoint of obtaining the developer, preferably 1.0 mPa · s or more, more preferably 1.2 mPa · s or more, still more preferably 1.3 mPa · s or more, and the viewpoint of improving the low temperature fixability of the liquid developer, and From the viewpoint of improving the grindability of toner particles to obtain a small particle diameter liquid developer, the viscosity is preferably 30 mPa · s or less, more preferably 10 mPa · s or less, still more preferably 5 mPa · s or less, still more preferably 3 mPa · s. s or less. When two or more insulating liquids are used in combination, the viscosity of the combined insulating liquid mixture may be within the above range.

  The liquid developer further includes various auxiliary materials such as emulsifiers, surfactants, stabilizers, wetting agents, thickeners, foaming agents, antifoaming agents, coagulants, gelling agents, antisettling agents, and charging. Control agents, antistatic agents, antiaging agents, softeners, plasticizers, fillers, flavoring agents, antiblocking agents, mold release agents, and the like may be included.

  The liquid developer of the present invention is obtained by dispersing toner particles in an insulating liquid in the presence of a dispersant. From the viewpoint of reducing the particle size of the toner particles in the liquid developer and from the viewpoint of reducing the viscosity of the liquid developer, the toner particles are dispersed in an insulating liquid, and the toner particles are wet pulverized to obtain a liquid developer Is preferred.

  As a method of mixing the toner particles, the dispersant, and the insulating liquid, a method of stirring using a stirring and mixing device is preferable. The stirring and mixing apparatus is not particularly limited, but a high speed stirring and mixing apparatus is preferable from the viewpoint of improving the productivity and storage stability of the toner particle dispersion, specifically, Despa (manufactured by Asada Iron Works, Ltd.), T. K. Homomixer, T. K. Homodisperser, T. K. Robomix (all, Primix Co., Ltd.), Clairemix (M. Tech. Co., Ltd.), K.D. Mill (K.D. International) Etc. are preferred.

  Wet grinding is a method of mechanically grinding toner particles dispersed in an insulating liquid in a state of being dispersed in the insulating liquid.

  As an apparatus used for wet pulverization, for example, a generally used stirring and mixing apparatus such as an anchor wing can be used. Among the stirring and mixing devices, high-speed stirring and mixing devices such as Despa (manufactured by Asada Iron Works, Ltd.) and T. K. Homomixer (manufactured by Primix, Inc.), mills, kneaders such as roll mills, beads mills, kneaders, extruders, etc. Etc. These devices can also be combined.

  Among these, from the viewpoint of reducing the particle diameter of toner particles, and the viewpoint of improving the storage stability by improving the dispersion stability of toner particles, and the viewpoint of reducing the viscosity of toner particle dispersion, use of a bead mill Is preferred.

  In the bead mill, toner particles having a desired particle size and particle size distribution can be obtained by controlling the particle size and filling ratio of the medium used, the circumferential velocity of the rotor, the residence time and the like.

  The solid content concentration of the liquid developer is preferably 10% by mass or more, more preferably 15% by mass or more, and still more preferably 20% by mass or more from the viewpoint of improving the image density, and the dispersion stability of the toner particles In order to improve the storage stability by improving the storage stability, the content is preferably 50% by mass or less, more preferably 45% by mass or less, and still more preferably 40% by mass or less. After preparation of the toner particle dispersion, if there is no operation such as dilution and concentration, the solid content concentration of the toner particle dispersion becomes the solid concentration of the liquid developer.

  The content of toner particles in the liquid developer is preferably 10% by mass or more, more preferably 15% by mass or more, and still more preferably 20% by mass or more from the viewpoint of high-speed printing, and the dispersion stability of the toner particles From the viewpoint of the properties, it is preferably 50% by mass or less, more preferably 45% by mass or less, and still more preferably 40% by mass or less.

The volume median particle diameter (D ₅₀ ) of the toner particles in the liquid developer is preferably 0.5 μm or more, more preferably 1 μm or more, and still more preferably 1.5 μm or more from the viewpoint of reducing the viscosity of the liquid developer. And, from the viewpoint of reducing the particle size of the toner particles and improving the image quality, it is preferably 5 μm or less, more preferably 3 μm or less, and still more preferably 2.5 μm or less.

  The content of the insulating liquid in the liquid developer is preferably 50% by mass or more, more preferably 55% by mass or more, and still more preferably 60% by mass or more from the viewpoint of dispersion stability of the toner particles. From the viewpoint of high-speed printing, it is preferably 90% by mass or less, more preferably 85% by mass or less, and still more preferably 80% by mass or less.

  The viscosity at 25 ° C. of the liquid developer having a solid content concentration of 25% by mass is preferably 3 mPa · s or more, more preferably 5 mPa · s, from the viewpoint of improving the dispersion stability of the toner particles and improving the storage stability. Or more, more preferably 6 mPa · s or more, still more preferably 7 mPa · s or more, and from the viewpoint of improving the fixability of the liquid developer, preferably 50 mPa · s or less, more preferably 40 mPa · s or less, further preferably Preferably it is 37 mPa · s or less, more preferably 35 mPa · s or less.

  An image can be printed on a resin film using the liquid developer of the present invention. Examples of resin films include films of polyvinyl chloride, polyvinylidene chloride, polyvinyl alcohol, polyethylene, ethylene / vinyl acetate copolymer, polypropylene, cellulose acetate, polyester (polyethylene terephthalate, polybutylene terephthalate etc.), polycarbonate etc. , Polyester films and polypropylene films are preferred.

  As a specific method of image printing on a resin film using a liquid developer, for example, a charging step of charging the photosensitive member, an exposure step of exposing the photosensitive member, and an electrostatic latent formed on the photosensitive member A developing step of causing toner particles in a liquid developer to adhere to an image to form a toner image, a transferring step of transferring the formed toner image to a resin film, and heating the transferred toner image to form a toner image The method includes the step of volatilizing and removing the insulating liquid contained, and the step of fixing the toner image to the resin film.

  EXAMPLES Hereinafter, the present invention will be specifically described by way of examples, but the present invention is not limited by these examples. Physical properties of the resin and the like were measured by the following methods.

[Softening point of resin]
Using a flow tester "CFT-500D" (manufactured by Shimadzu Corporation), while heating a 1 g sample at a heating rate of 6 ° C./min, a load of 1.96 MPa is applied by a plunger, diameter 1 mm, length 1 mm Push out of the nozzle. The plunger drop amount of the flow tester is plotted against the temperature, and the temperature at which half of the sample flowed out is taken as the softening point.

[Acid value of resin]
It measures by the method of JIS K0070. However, only the measurement solvent is changed to a mixed solvent of 2-propanol and toluene (2-propanol: toluene = 2: 1 (mass ratio)) from a mixed solvent of ethanol and ether defined in JIS K 0070.

[Amine value of resin]
Measurement is performed using a potentiometric titrator (manufactured by Kyoto Denshi K. K., AT-510) according to JIS K2501.

Viscoelastic measurement of resin
(1) Preparation of sample A box of dimension width 5 mm, length 50 mm, depth 3 mm made of release paper was attached to a metal plate, and about 0.6 g of polyamide resin powder was put in the box and set at 120 ° C. Place on a hot plate and melt the resin powder. Quench the molten resin evenly in the box and take out the resin pieces from the box.
Measure the width and thickness of the resin piece accurately with a vernier caliper.
The width of the resin piece used for measurement is 4.5 mm or more and 6 mm or less, the thickness is 1.0 or more and 2.0 mm or less, and the length is 45 mm or more and 50 mm or less.
(2) Measurement of storage elastic modulus Dynamic viscoelasticity measuring apparatus “DVA-225” (manufactured by IT Measurement & Control Co., Ltd.) equipped with a jig for tension, sample dimensions (grip length, width, thickness), The deformation mode is tensile, static / dynamic stress ratio 1.5, strain 0.02%, constant temperature rise rate 2 ° C / min, measurement frequency 10Hz, upper limit elongation 70%, minimum load 2cN, sampling interval 2 ° C / min, and lower limit Enter the elastic modulus 10E5Pa, sandwich the sample prepared in (1) with a jig for tension, apply appropriate tension and then cool to -70 ° C with liquid nitrogen and start measurement temperature -50 ° C, measurement upper limit temperature Measure the storage modulus up to 70 ° C., the loss modulus, and the loss tangent (tan δ).
(3) Determination of Glass Transition Temperature (Tg) The temperature at the peak top of the loss tangent (tan δ) in the above (2) is taken as the glass transition temperature (Tg).

[Weight-average molecular weight of resin (Mw)]
The molecular weight distribution is measured by gel permeation chromatography (GPC) to determine the weight average molecular weight.
〔Measurement condition〕
Column: GMMHR-H (manufactured by Tosoh Corporation) x 2
Column temperature: 40 ° C
Detector: RI
Eluent: Chloroform flow rate: 1.0 mL / min
Injection volume: 0.1 mL
Standard: Polystyrene

[Volume median particle size of toner particles before mixing with insulating liquid]
Measuring machine: Coulter Multisizer II (manufactured by Beckman Coulter Co., Ltd.)
Aperture diameter: 100 μm
Analysis software: Coulter multisizer Accucomp version 1.19 (manufactured by Beckman Coulter Co., Ltd.)
Electrolyte: Isoton II (manufactured by Beckman Coulter Co., Ltd.)
Dispersion solution: Emulgen 109P (manufactured by Kao Corporation, polyoxyethylene lauryl ether, HLB (glyphin): 13.6) dissolved in electrolyte to adjust to 5% by mass Dispersion conditions: 10 mg of measurement sample in 5 mL of the dispersion Is added, and dispersed for 1 minute with an ultrasonic dispersion machine (machine name: US-1, manufactured by SND Co., Ltd., output: 80 W). Thereafter, 25 mL of the electrolytic solution is added, and the mixture is dispersed for 1 minute with an ultrasonic dispersion machine to prepare a sample dispersion.
Measurement conditions: The sample dispersion is added to 100 mL of the electrolyte so that the particle size of 30,000 particles can be measured in 20 seconds, 30,000 particles are measured, and the volume is determined from the particle size distribution. Determine the median particle size (D ₅₀ ).

[Weight-average molecular weight of dispersant (Mw)]
The molecular weight distribution is measured by gel permeation chromatography (GPC) method shown below, and the number average molecular weight (Mn) and the weight average molecular weight (Mw) are determined.
(1) Preparation of sample solution The dispersant (distilling off the insulating liquid from the dispersant solution) is dissolved in tetrahydrofuran so that the concentration becomes 0.5 g / 100 mL. Next, this solution is filtered using a fluorine resin filter “FP-200” (manufactured by Sumitomo Electric Industries, Ltd.) having a pore size of 0.2 μm to remove insoluble components, and this is used as a sample solution.
(2) Molecular weight measurement Using the following measuring device and analysis column, flow tetrahydrofuran as an eluent at a flow rate of 1 mL per minute, and stabilize the column in a 40 ° C. thermostat. Then, 100 μL of the sample solution is injected to perform measurement. The molecular weight of the sample is calculated based on a calibration curve prepared in advance. The calibration curve at this time includes several types of monodispersed polystyrene (A-500 (5.0 × 10 ² ), A-1000 (1.01 × 10 ³ ), A-2500 (2.63 × 10 ³ ), manufactured by Tosoh Corporation), A-5000 (5.97 × 10 ³ ), F-1 (1.02 × 10 ⁴ ), F-2 (1.81 × 10 ⁴ ), F-4 (3.97 × 10 ⁴ ), F-10 (9.64 × 10 ⁴ ), Those prepared using F-20 (1.90 × 10 ⁵ ), F-40 (4.27 × 10 ⁵ ), F-80 (7.06 × 10 ⁵ ), and F-128 (1.09 × 10 ⁶ ) as standard samples are used.
Measuring device: HLC-8220GPC (made by Tosoh Corporation)
Analysis column: GMHXL + G3000HXL (made by Tosoh Corporation)

[Amine value of dispersant]
The sample is precisely weighed in a 100 mL beaker, and 50 mL of a mixed solvent of ethanol and toluene (mass ratio 1: 1) in which bromocresol green is previously dissolved is added to dissolve the sample.
Using a potentiometric titrator, titrate with 0.2 mol / L alcoholic hydrochloric acid standard solution. A blank test is also conducted at the same time, and the amine value is calculated from the following formula.
Amine value (mg KOH / g) = (A-B) × M × f × 56.108 / sampling amount (g)
A = Titration of this test (mL)
B = Titer of empty test (mL)
M = molar concentration of alcoholic hydrochloric acid standard solution (mol / L)
f = factor of alcoholic hydrochloric acid standard solution
56.108 = Molecular weight of KOH (g / mol)

[Conductivity of Insulating Liquid]
25 g of a sample is put in a 40 mL glass sample tube “screw No. 7” (manufactured by Marumu Co., Ltd.), and the non-aqueous conductivity meter “DT-700” (manufactured by Dispersion Technology) is used to insulate the electrode. Immerse in liquid and measure 20 times at 25 ° C. to calculate the average value and measure the conductivity. The smaller the value, the higher the resistance.

[Viscosity of Insulating Liquid and Liquid Developer at 25 ° C.]
Put 4 to 5 mL of the measurement solution into a 6 mL glass sample tube “screw No. 2” (manufactured by Marem Co., Ltd.), and use a rotational vibration viscometer “Biscomate VM-10A-L” (Seconik Corp., detection terminal) : Measure viscosity at 25 ° C. using titanium, φ 8 mm).

[Solid content concentration of liquid developer]
Ten parts by mass of the sample is diluted with 90 parts by mass of hexane and rotated for 20 minutes at a rotational speed of 25,000 r / min using a centrifugal separator "3-30 KS" (manufactured by Sigma). After standing, the supernatant is removed by decantation, diluted with 90 parts by mass of hexane, and centrifuged again under the same conditions. After removing the supernatant liquid by decantation, the lower layer is dried with a vacuum dryer at 0.5 kPa and 40 ° C. for 8 hours, and the solid content concentration is calculated from the following equation.

[Volume median particle diameter (D ₅₀ ) of toner particles in liquid developer]
Using a laser diffraction / scattering particle sizer “Mastersizer 2000” (manufactured by Malvern Co., Ltd.), add Isopar G (manufactured by ExxonMobil, isoparaffin, viscosity 1 mPa · s at 25 ° C.) to the measurement cell, and scatter intensity The volume median particle size (D ₅₀ ) is measured under the conditions of a particle refractive index of 1.58 (imaginary part 0.1) and a dispersion medium refractive index of 1.42 at a concentration of 5 to 15%.

Resin Production Example The carboxylic acid components shown in Table 1 were placed in a 1 L separable flask equipped with a Dean-Stark tube equipped with a condenser, and heated to 70 ° C. while stirring under a nitrogen atmosphere. After nitrogen substitution under reduced pressure, the mixture of amine components shown in Table 1 was slowly dropped. When the heat ceased, the temperature was raised to 145 ° C. to promote dehydration. It was kept at that temperature for 1 hour. Thereafter, the temperature was slowly raised to 210 ° C. and held for 6 hours. After reacting for 0.5 hour at 40 kPa, the reaction product was cooled, poured into a vat at 120 ° C., solidified, and crushed into small pieces to obtain polyamide resins (Resins A to K).

  Furthermore, the film adhesiveness of the polyamide resin to a polyethylene terephthalate (PET) film and a polypropylene (PP) film was evaluated by the following tape peel test and peel strength measurement.

[Film adhesion]
(1) Tape peeling test According to old JIS K5400, film adhesiveness was evaluated. A resin solution in which the resin is dissolved at a concentration of 25% by mass with a mixed solvent of isopropyl alcohol / toluene = 2/1 (mass ratio) is a PET film of 20 cm long and 20 cm wide (P2241, Toyobo, film thickness 20 μm) Using a bar coater No. 6 (calculated liquid film thickness of 13.7 μm) for a PP film (VM-PET1011HG-AS, made by Toray, film thickness 12 μm) with a vertical width of 20 cm and a horizontal width of 20 cm. The resultant was applied at a speed of 2 m / min with Mitsui Electric Seiki Co., Ltd., and then dried for 10 minutes with a dryer at 80 ° C. Using a cutter knife, the surface to be coated was cut with 11 cuts (cut distance of 1 mm) to reach the substrate, to prepare 100 grids. Next, cellotape (registered trademark) (cellophane adhesive tape 24 mm wide JIS Z 1522) is strongly pressed to this grid portion using an eraser, and then the end of the tape is peeled off at a 45 ° angle, The film adhesion was evaluated according to the following evaluation criteria.
〔Evaluation criteria〕
A: There is no detachment of any grid eyes.
B: There is a small peeling of the coating at the intersection of cuts. The number of peeled grids is less than 5% of the total grid.
C: The coating is peeled off at the intersections along the line of the cut. The number of grids with peeling is 5% or more and less than 15% of the entire grid.
D: The coating is partially and completely peeled off along the cut line. The number of grids with peeling is more than 15% and less than 65% of the entire grid.

(2) Peeling strength measurement According to JIS K 6854-3: 1999 "Adhesive-Peeling adhesive strength test method-Part 3 T-type peeling" by the following method, polyester film (PET film) and polypropylene film ( Maximum peel strength for PP film was measured.
<PET film>
A solution obtained by dissolving a resin in a mixed solvent of isopropyl alcohol / toluene = 2/1 (mass ratio) at a concentration of 25% by mass is a PET film (FE 2001, produced by Futamura Chemical Co., Ltd.) with a width of 25 cm and a width of 20 cm. Using a bar coater No. 6 (calculated liquid film thickness of 13.7 μm) on a corona-treated surface with a thickness of 12 μm, coat at a speed of 2 m / min with a tabletop coating machine TC-1 (made by Mitsui Electric Seiki Co., Ltd.) did. Then, after drying for 10 minutes with a dryer at 80 ° C., the corona-treated surface of the uncoated PET film was placed on the coated surface, and two films were pressure bonded at 120 ° C. and 0.7 m / min. The laminated film was cut out with a width of 25 mm, and then the tension was set at a speed of 10 mm / min according to JIS K 6854-3: 1999 “Adhesive-Peel adhesion test method-Part 3 T-type peeling”. The maximum peel strength was determined with a tester and converted to a width of 15 mm.
<PP film>
The maximum peel strength was similarly determined using a PP film (FOR, manufactured by Futamura Chemical Co., Ltd., thickness: 25 μm, single-sided corona-treated product) instead of the PET film and converted to a width of 15 mm.

  Physical properties and film adhesiveness of polyamide resins (Resins A to L) used in Examples and Comparative Examples are shown in Table 2.

Production Example 1 of Dispersant
In a 300 mL four-neck separable flask, 9 g of polyethyleneimine 1200 (Epomin SP-012, manufactured by Junsei Chemical Co., Ltd.), 59.9 g of maleic anhydride modified polypropylene (X-10065, manufactured by Baker Hughes), 68.9 g of xylene as a solvent In the nitrogen stream, the temperature was raised to 140 ° C. with stirring for 1.5 hours, and the reaction water was distilled off using a Dean-Stark tube. Thereafter, the temperature was raised to 160 ° C. over 2 hours, and the pressure was further reduced to 100 Torr to completely distill off the xylene. After cooling to 100 ° C. and taking it out of the flask, it was solidified on a vat. In addition, it was confirmed that the peak derived from the acid anhydride of maleic anhydride-modified polypropylene, which was observed at 1770 cm ^-1 by FT-IR, disappeared in the reaction. The reaction product sufficiently solidified and crystallized at room temperature was pulverized by a laboratory mixer to obtain dispersant A. The weight average molecular weight of Dispersant A was 98,000, and the amine value was 1.6 mg KOH / g.

Production Example 2 of Dispersant
In a 300-ml four-neck separable flask, 7.6 g of polyethyleneimine 600 (Epomin SP-006, manufactured by Junsei Chemical Co., Ltd.), 74.9 g of maleic anhydride-modified polyisobutylene (manufactured by H1000 Dover Chemical), and 82.5 g of xylene as a solvent are placed. The temperature was raised to 140 ° C. with stirring in a nitrogen stream over 1.5 hours, and the reaction water was distilled off using a Dean-Stark tube. Thereafter, the temperature was raised to 160 ° C. over 2 hours, and the pressure was further reduced to 100 Torr to completely distill off the xylene. It cooled to 70 degreeC and took out from the flask. In addition, it was confirmed that the peak derived from the acid anhydride of maleic anhydride-modified polyisobutylene, which was observed at 1770 cm ^-1 by FT-IR, disappeared in the reaction, to obtain Dispersant C. The weight average molecular weight of the dispersing agent C was 50.000, and the amine value was 1.2 mg KOH / g.

Examples 1 to 9 and Comparative Examples 1 to 6
In a table-top kneader (PBV-0.3, manufactured by Irie Shokai), 144 g (80 parts by mass) of a binding resin shown in Table 3 and a coloring agent "ECB-301" (manufactured by Dainichi Seika Kogyo Co., Ltd., Phthalocyanine Blue 15: 3) 36 g (20 parts by mass) was charged, and the mixture was stirred and kneaded at 90 ° C. for 10 minutes. The obtained kneaded product was roughly pulverized by a coffee mill and then pulverized by a supersonic jet pulverizer (manufactured by Nippon Pneumatic Mfg. Co., Ltd.) to obtain toner particles. The particle size of the obtained toner particles was about 10 to 15 μm.

  15 g (25 parts by mass) of toner particles, 0.9 g of dispersant shown in Table 3 (1.8 g of dispersant B) (1.5 parts by mass), 44.1 g (73.55 parts by mass) of insulating liquid shown in Table 3, and 0.8 mm diameter 390 g of the above zirconia beads were placed in a 250 mL container, dispersed with a paint shaker (manufactured by Asada Iron Works Co., Ltd.) for 6 hours, and wet-pulverized to obtain a liquid developer having a solid content concentration of 26.5 mass%. Physical properties of the obtained liquid developer are shown in Table 3.

Test example (film adhesion)
(1) Tape peeling test According to old JIS K5400, film adhesiveness was evaluated. Liquid developer was applied to PET film (P2241, Toyobo, film thickness 20 μm) and PP film (VM-PET1011HG-AS, Toray, film thickness 12 μm) using a bar coater No. 6 at a speed of 2 m / min. It was applied and then dried in an oven at 80 ° C. for 10 minutes. Using a cutter knife, the surface to be coated was cut with 11 cuts (cut distance of 1 mm) to reach the substrate, to prepare 100 grids. Next, cellotape (registered trademark) (cellophane adhesive tape 24 mm wide JIS Z 1522) is strongly pressed to this grid portion using an eraser, and then the end of the tape is peeled off at a 45 ° angle, The film adhesion was evaluated according to the following evaluation criteria. The results are shown in Table 3.
〔Evaluation criteria〕
A: There is no detachment of any grid eyes.
B: There is a small peeling of the coating at the intersection of cuts. The number of peeled grids is less than 5% of the total grid.
C: The coating is peeled off at the intersections along the line of the cut. The number of grids with peeling is 5% or more and less than 15% of the entire grid.
D: The coating is partially and completely peeled off along the cut line. The number of grids with peeling is more than 15% and less than 65% of the entire grid.

(2) Peeling strength measurement According to JIS K 6854-3: 1999 "Adhesive-Peeling adhesive strength test method-Part 3 T-type peeling" by the following method, polyester film (PET film) and polypropylene film ( Maximum peel strength for PP film was measured. The results are shown in Table 3.
<PET film>
The liquid developer was coated on a corona-treated surface of a PET film (FE 2001, manufactured by Futamura Chemical Co., Ltd., thickness: 12 μm) using a bar coater No. 6 at a speed of 2 m / min. Then, after drying for 10 minutes with a dryer at 80 ° C., the corona-treated surface of the uncoated PET film was placed on the coated surface, and two films were pressure bonded at 120 ° C. and 0.7 m / min. The laminated film was cut out with a width of 25 mm, and then the tension was set at a speed of 10 mm / min according to JIS K 6854-3: 1999 “Adhesive-Peel adhesion test method-Part 3 T-type peeling”. The maximum peel strength was determined with a tester and converted to a width of 15 mm.
<PP film>
The maximum peel strength was similarly determined using a PP film (FOR, manufactured by Futamura Chemical Co., Ltd., thickness: 25 μm, single-sided corona-treated product) instead of the PET film and converted to a width of 15 mm.

  From the above results, the liquid developers of Examples 1 to 9 in which the polymerized fatty acid-modified polyamide resin having a predetermined storage elastic modulus is used as the binder resin are polyester films, in contrast to the liquid developers of Comparative Examples 1 to 6. And excellent adhesion to each of the polypropylene films.

  The liquid developer of the present invention is suitably used, for example, for developing a latent image formed in an electrophotographic method, an electrostatic recording method, an electrostatic printing method or the like.

Claims (6)

A liquid developer containing toner particles containing a binder resin and a colorant, a dispersant, and an insulating liquid, wherein the binder resin is a polycondensate of a carboxylic acid component containing a polymerized fatty acid and an amine component, A liquid developer containing a polyamide resin having a storage elastic modulus at 25 ° C. of 2.0 × 10 ⁸ Pa or less.   When the liquid developer is formed into a film and adhered to a film selected from a polyester film and a polypropylene film according to JIS K 6854-3: 1999, the maximum peel strength is 0.5 N to 10 N in terms of 15 mm width, The liquid developer according to claim 1.   3. The method according to claim 1, wherein the content of the polymerized fatty acid in the carboxylic acid component is 70 mol% or more, the content of ethylene diamine in the amine component is 80 mol% or less, and the m-xylene diamine is 20 mol% or more. Liquid developer.   A toner developer containing a binder resin and a colorant, a dispersant, and a liquid developer containing an insulating liquid, wherein the binder resin is formed into a film, and a polyester film and a polypropylene are formed according to JIS K 6854-3: 1999. The liquid developer whose maximum peeling strength at the time of making it adhere | attach to the film chosen from a film is 0.5N or more and 10N or less in 15 mm width conversion.   A method for printing an image on a resin film using the liquid developer according to any one of claims 1 to 4, wherein the resin film is a polyester film.   A method of printing an image on a resin film using the liquid developer according to any one of claims 1 to 4, wherein the resin film is a polypropylene film.