JP6459663B2 - Liquid developer, liquid developer cartridge, image forming apparatus, and image forming method - Google Patents

Description

  The present invention relates to a liquid developer, a liquid developer cartridge, an image forming apparatus, and an image forming method.

For example, Patent Document 1 discloses a toner containing at least a binder resin, a colorant, and a polyalkylene glycol ester compound represented by a specific general formula.
Patent Document 2 is granulated in an aqueous medium using at least a binder resin containing a crystalline polyester resin, a colorant, a release agent, and a plasticizer represented by a specific structural formula. Toner is disclosed.

Patent Document 3 discloses a liquid developer “containing an insulating liquid containing a fatty acid monoester and toner particles mainly composed of a polyester resin”.
Patent Document 4 states that “the toner particles are mainly composed of a resin material and a non-volatile insulating liquid, and the toner particles include a liquid having a composition different from that of the insulating liquid. The liquid contained in the toner particles has an aniline point lower than that of the insulating liquid. ”A liquid developer is disclosed.

JP2012-203124A JP2013-083756A JP 2008-225442 A JP 2008-299142 A

  An object of the present invention is to provide a liquid developer having a carrier liquid containing a compound having an ester skeleton, wherein the compound having an ester skeleton is a saturated aliphatic monovalent carboxylic acid ester compound (reaction product of a monohydric alcohol and a monovalent carboxylic acid). Or a saturated aliphatic polyvalent carboxylic acid ester compound (reaction product of a monohydric alcohol and a divalent or higher polyvalent carboxylic acid), and has low-temperature fixability and suppresses image loss. The object is to provide a liquid developer.

The above-mentioned subject is achieved by the following invention.
The invention according to <1>
Toner particles,
Carrier liquid,
A polyhydric alcohol ester compound comprising a reaction product of a linear or branched saturated aliphatic polyhydric alcohol and a linear or branched saturated aliphatic monovalent carboxylic acid, contained in the carrier liquid;
A liquid developer having

The invention according to <2>
The liquid developer according to <1> , wherein the polyhydric alcohol ester compound has a conductivity of 10 ⁻¹¹ S / m or less.

The invention according to <3>
The liquid developer according to <1> or <2> , wherein the saturated aliphatic polyhydric alcohol has a valence of 3 to 6.

The invention according to <4>
The liquid developer according to any one of <1> to <3> , wherein the carrier liquid contains 50% by mass or more and 100% by mass or less of silicone oil as a content with respect to the total amount of the carrier liquid.

The invention according to <5>
<1> to a liquid developer cartridge that accommodates the liquid developer according to any one of <4> and is detachable from the image forming apparatus.

The invention according to <6>
An electrostatic latent image carrier;
A charging device for charging the surface of the electrostatic latent image holding member;
A latent image forming apparatus that forms an electrostatic latent image on the surface of the electrostatic latent image holding member;
The liquid developer according to any one of <1> to <4> is stored, and the electrostatic latent image formed on the surface of the electrostatic latent image holding member is developed with the liquid developer. A developing device for forming a toner image;
A transfer device for transferring the toner image to a recording medium;
A fixing device for fixing the toner image on the recording medium to the recording medium;
An image forming apparatus having

The invention according to <7>
A charging step for charging the surface of the electrostatic latent image holding member;
A latent image forming step of forming an electrostatic latent image on the surface of the electrostatic latent image holder;
A developing step of developing the electrostatic latent image formed on the surface of the electrostatic latent image holding member with the liquid developer according to any one of <1> to <4> to form a toner image;
A transfer step of transferring the toner image to a recording medium;
A fixing step of fixing the toner image on the recording medium to the recording medium;
Is an image forming method.

The invention according to <8>
<7> The image forming method according to <7> , wherein the recording medium is at least one selected from the group consisting of a polyethylene terephthalate film, a polypropylene film, and a nylon film.

According to the invention according to <1> , in the liquid developer having a carrier liquid containing a compound having an ester skeleton, the compound having an ester skeleton is a saturated aliphatic monovalent carboxylic acid ester compound (monohydric alcohol and monovalent carboxylic acid). Product or a saturated aliphatic polyvalent carboxylic acid ester compound (reaction product of a monohydric alcohol and a divalent or higher polyvalent carboxylic acid), and has a low temperature fixability, and an image. Provided is a liquid developer that is prevented from coming off.

According to the invention according to <2>, there is provided a liquid developer having a low-temperature fixability and suppressing image loss as compared with a case where the electrical conductivity of the polyhydric alcohol ester compound exceeds 10 ⁻¹¹ S / m. Is done.

According to the invention according to <3> , a liquid developer having a low-temperature fixability and suppressing image omission as compared with the case where the valence of the polyhydric alcohol ester compound is less than 3 or more than 6. Is provided.

According to the invention according to <4> , in the liquid developer having a carrier liquid containing a compound having an ester skeleton, the compound having an ester skeleton is a saturated aliphatic monovalent carboxylic acid ester compound (monohydric alcohol and monovalent carboxylic acid). Product), or saturated aliphatic polyvalent carboxylic acid ester compound (reaction product of monohydric alcohol and divalent or higher polyvalent carboxylic acid), the carrier liquid is the total amount of the carrier liquid Even if it contains 50 mass% or more and 100 mass% or less of silicone oil, the liquid developer which has low-temperature fixability and the image omission is suppressed is provided.

According to the invention according to <5> , <6> , <7> , or <8> , in a liquid developer having a carrier liquid containing a compound having an ester skeleton, the compound having an ester skeleton is saturated aliphatic monovalent. Carboxylic acid ester compound (reaction product of monohydric alcohol and monovalent carboxylic acid) or saturated aliphatic polyvalent carboxylic acid ester compound (reaction product of monohydric alcohol and divalent or higher polyvalent carboxylic acid) There is provided a liquid developer cartridge, an image forming apparatus, or an image forming method that has low temperature fixability and suppresses image omission as compared with a case where a certain liquid developer is applied.

1 is a schematic configuration diagram illustrating an example of an image forming apparatus according to an exemplary embodiment. It is a schematic block diagram which shows another example of the image forming apparatus of this embodiment.

  Embodiments that are examples of the present invention will be described below.

<Liquid developer>
The liquid developer according to the exemplary embodiment includes toner particles, a carrier liquid, and a carrier liquid, and includes a linear or branched saturated aliphatic polyhydric alcohol, and a linear or branched saturated aliphatic monovalent carboxylic acid. And a polyhydric alcohol ester compound (hereinafter also referred to as “specific polyhydric alcohol ester compound”) which is a reaction product of an acid.

  In the liquid developer according to this embodiment, the compound having an ester skeleton is a saturated aliphatic monovalent carboxylic acid ester compound (a reaction product of a monohydric alcohol and a monovalent carboxylic acid) or a saturated aliphatic due to the above configuration. Compared with the case of a polyvalent carboxylic acid ester compound (reaction product of a monohydric alcohol and a divalent or higher polyvalent carboxylic acid), it has a low-temperature fixability and image loss is suppressed. The reason is guessed as shown below.

  A thermoplastic resin film (for example, a polypropylene film or a polyethylene terephthalate film) may be used as a recording medium for forming an image using a liquid developer containing carrier liquid and toner particles. Examples of applications in this case include labels, posters, various packaging materials (for example, flexible packaging materials) and the like.

In the case of forming an image on a thermoplastic resin film, if a fixing temperature for fixing the image, for example, a temperature equivalent to that for fixing an image on paper is adopted, the thermoplastic resin film may be deformed by heat. There is. Further, for example, when the thermoplastic resin film is applied to a soft packaging material, the suitability as the flexible packaging material may be reduced due to deformation of the base film.
On the other hand, when the fixing temperature is lowered for the purpose of suppressing deformation of the thermoplastic resin film, the temperature is low, so that the toner particles are insufficiently melted and formed on the thermoplastic resin film and the thermoplastic resin film. Fixability with an image may be lowered. Further, for example, when the thermoplastic resin film is applied to a soft packaging material, the toner particles are not sufficiently melted. Therefore, a phenomenon such as a decrease in adhesion between the thermoplastic resin film on which an image is formed and another material to be laminated is observed, and the suitability as a flexible packaging material may be decreased.

  For example, when a plasticizer (for example, a compound having an ester skeleton) is included in a carrier liquid of a liquid developer having a non-volatile carrier liquid, the plasticizer is in contact with the binder resin in the toner particles. An effect of plasticizing occurs. Therefore, the melting temperature of the toner particles is lowered, and the fixing temperature when fixing the image is lowered. Thereby, the fixability between the thermoplastic resin film and the image formed on the thermoplastic resin film is easily improved.

However, when the compound having an ester skeleton is a saturated aliphatic monovalent carboxylic acid ester compound, an excessive plastic effect is exhibited with respect to the toner particles, and a phenomenon such as dissolution of the toner particles is observed. It may be difficult to apply as an agent.
On the other hand, it has been found that a compound having an ester skeleton functioning as a plasticizer causes image omission due to its chemical structure. When the compound having an ester skeleton is a saturated aliphatic polyvalent carboxylic acid ester compound, the effect of plasticizing the toner particles is shown, but image omission may occur. This is presumably because the chemical structure of the polyvalent carboxylic acid ester compound exhibits high adsorptivity to moisture, so that the resistance value of the toner particles tends to decrease with time and causes a decrease in transferability.

  On the other hand, the liquid developer of this embodiment contains a specific polyhydric alcohol ester compound in the carrier liquid. Therefore, it has low temperature fixability due to the plasticizing effect exhibited by the specific polyhydric alcohol ester compound. In addition, the specific polyhydric alcohol ester compound has a unique chemical structure obtained by reacting a saturated aliphatic polyhydric alcohol having two or more valences with a saturated aliphatic monohydric carboxylic acid. It is considered that the moisture adsorptivity is lower than that of the compound. Therefore, the resistance value of the toner particles does not easily decrease with time, and the resistance value is stabilized. Further, it is considered that image dropout is suppressed by suppressing a decrease in transferability.

  From the above, even if the liquid developer according to the present embodiment forms an image on the thermoplastic resin film, the compound having an ester skeleton contained in the carrier liquid is a saturated aliphatic monovalent carboxylic acid ester compound or a saturated Compared to the case of an aliphatic polyvalent carboxylic acid ester compound, it is presumed to have low-temperature fixability and to suppress image omission.

  In addition, for example, when forming an image on a thermoplastic resin film for a soft packaging material, the thermoplastic resin film is unwound from the wound thermoplastic resin film, and the image is formed on the thermoplastic resin film. After being formed, it is often wound up and stored again. In this case, the image formed on the thermoplastic resin film is superimposed on the image with the opposite surface of the thermoplastic resin film on which the image is formed being loaded. Therefore, a phenomenon may occur in which an image formed on the thermoplastic resin film moves to the surface of the superimposed thermoplastic resin film (this phenomenon is also referred to as “image durability” or “document offset”). .

  On the other hand, the liquid developer according to the exemplary embodiment has improved low-temperature fixability to a thermoplastic resin film because the carrier liquid contains a specific polyhydric alcohol ester compound. Therefore, even when an image is formed on a thermoplastic resin film for soft packaging material using the liquid developer of this embodiment, image durability is high and occurrence of document offset is suppressed.

  A compound having an ester skeleton may show a plasticizing effect on a thermoplastic resin film. The liquid developer according to the exemplary embodiment has a bulky structure because the specific polyhydric alcohol ester compound has a specific chemical structure. Therefore, it is considered that a compound having an ester skeleton has a milder plasticizing effect on toner particles than a polyvalent carboxylic acid ester compound or a monovalent carboxylic acid ester compound. And since it is thought that the plasticizing effect with respect to a thermoplastic resin film is also moderate, a deformation | transformation of a plastic resin film is also suppressed.

  In the present embodiment, the “film” is a concept that includes not only a generally called “film” but also a generally called “sheet”.

  Hereinafter, the configuration of the liquid developer according to this embodiment will be described in detail.

[Toner particles]
First, the constituent materials of the toner particles in the present embodiment will be described in detail. The toner particles in this embodiment have toner particles containing a binder resin.

  The toner particles include a binder resin and, for example, a colorant, a release agent, and other additives as necessary.

(Binder resin)
The binder resin used in the toner particles of the exemplary embodiment is not particularly limited, but is preferably synthesized by a polyaddition reaction or a polycondensation reaction from the viewpoint of low-temperature fixability and storage stability. Specific examples include polyester resins, polyurethane resins, epoxy resins, polyol resins and the like. Among these, a polyester resin is desirably used from the viewpoint of compatibility with the crystalline resin used in combination and inclusion of a release agent.

As described above, in the present embodiment, it is desirable to use a crystalline resin as the binder resin in addition to the amorphous resin from the viewpoint of obtaining sharp melting characteristics at the time of fixing.
In the present embodiment, the “crystalline resin” refers to a resin having a clear endothermic peak instead of a stepwise endothermic amount change in differential scanning calorimetry (DSC). Specifically, it means a crystalline resin having a weight average molecular weight of more than 5000, and usually means a crystalline resin having a weight average molecular weight of 10,000 or more.
In the present embodiment, the “amorphous resin” refers to a resin having a half-value width exceeding 10 ° C., a resin that exhibits a stepwise endothermic change, or a resin that does not have a clear endothermic peak.

-Crystalline resin-
The crystalline resin has a melting temperature, so that the viscosity is greatly reduced at a specific temperature. When toner particles are heated during fixing, the crystalline resin molecule can be fixed after the thermal activity of the crystalline resin molecules starts. Thus, a further excellent low-temperature fixability can be imparted. The content of the crystalline resin in the toner particles is preferably in the range of 1% by mass to 10% by mass, and more preferably in the range of 2% by mass to 8% by mass.

  As the crystalline resin used in the present embodiment, a resin having a melting temperature (Tm) in the range of 45 ° C. or higher and 110 ° C. or lower is suitable for ensuring low temperature fixability and toner particle storage stability. A more desirable melting temperature range is 50 ° C. or more and 100 ° C. or less, and a further desirable range is 55 ° C. or more and 90 ° C. or less. The melting temperature of the resin is determined by a method based on ASTM D3418-8.

  Further, the number average molecular weight (Mn) of the crystalline resin is preferably 2000 or more, and more preferably 4000 or more.

  As the crystalline resin used in the present embodiment, a resin having a weight average molecular weight exceeding 5000 and having crystallinity is desirable, and specific examples thereof include crystalline polyester resins and crystalline vinyl resins. A polyester resin is desirable. An aliphatic crystalline polyester resin having an appropriate melting temperature is more desirable.

  Examples of the crystalline vinyl resin include amyl (meth) acrylate, hexyl (meth) acrylate, heptyl (meth) acrylate, octyl (meth) acrylate, nonyl (meth) acrylate, and decyl (meth) acrylate. , Undecyl (meth) acrylate, tridecyl (meth) acrylate, myristyl (meth) acrylate, cetyl (meth) acrylate, stearyl (meth) acrylate, oleyl (meth) acrylate, behenyl (meth) acrylate, etc. And vinyl resins using long-chain alkyl and alkenyl (meth) acrylic acid esters.

In the present specification, “(meth) acryl” means to include both “acryl” and “methacryl”.
In addition, “(meth) acrylate” means that both “acrylate” and “methacrylate” are included.

  On the other hand, the crystalline polyester resin is preferably a polycondensate synthesized from a carboxylic acid (dicarboxylic acid) component and an alcohol (diol) component. Hereinafter, the carboxylic acid component and the alcohol component will be described in more detail. In the present embodiment, a copolymer obtained by copolymerizing other components in a proportion of 50% by mass or less with respect to the main chain of the crystalline polyester resin is also referred to as a crystalline polyester resin.

  The carboxylic acid component is preferably an aliphatic dicarboxylic acid, and particularly preferably a linear carboxylic acid. For example, oxalic acid, malonic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelic acid, sebacic acid, 1,9-nonanedicarboxylic acid, 1,10-decanedicarboxylic acid, 1,11-undecane Dicarboxylic acid, 1,12-dodecanedicarboxylic acid, 1,13-tridecanedicarboxylic acid, 1,14-tetradecanedicarboxylic acid, 1,16-hexadecanedicarboxylic acid, 1,18-octadecanedicarboxylic acid, etc., or lower alkyl esters thereof And acid anhydrides, but are not limited thereto.

  As the carboxylic acid component, in addition to the above-mentioned aliphatic dicarboxylic acid component, it is desirable to include components such as a dicarboxylic acid component having a double bond and a dicarboxylic acid component having a sulfonic acid group. The dicarboxylic acid component having a double bond includes a component derived from a lower alkyl ester or acid anhydride of a dicarboxylic acid having a double bond, in addition to a component derived from a dicarboxylic acid having a double bond. Is also included. The dicarboxylic acid component having a sulfonic acid group includes a component derived from a dicarboxylic acid having a sulfonic acid group, a lower alkyl ester of a dicarboxylic acid having a sulfonic acid group, or an acid anhydride. Is also included.

  The dicarboxylic acid having a double bond is preferably used because it can crosslink the entire resin using the double bond. Examples of such dicarboxylic acids include, but are not limited to, fumaric acid, maleic acid, 3-hexenedioic acid, and 3-octenedioic acid. Moreover, these lower alkyl esters, acid anhydrides, etc. are also mentioned. Among these, fumaric acid, maleic acid and the like are desirable in terms of cost.

  The dicarboxylic acid having a sulfonic acid group is effective in that it can improve the dispersion of a coloring material such as a pigment. Moreover, if there exists a sulfonic acid group when emulsifying or suspending the whole resin in water and producing particle | grains, as mentioned later, it can emulsify or suspend without using surfactant. Examples of the dicarboxylic acid having a sulfonic acid group include, but are not limited to, 2-sulfoterephthalic acid sodium salt, 5-sulfoisophthalic acid sodium salt, and sulfosuccinic acid sodium salt. Moreover, these lower alkyl esters, acid anhydrides, etc. are also mentioned. Among these, 5-sulfoisophthalic acid sodium salt and the like are desirable in terms of cost.

The content of the carboxylic acid component other than these aliphatic dicarboxylic acid components (dicarboxylic acid component having a double bond or dicarboxylic acid component having a sulfonic acid group) in the carboxylic acid component is 1 to 20 mol. % Or less is desirable, and more than 2 component mol% and 10 component mol% is more desirable.
In the present embodiment, “constituent mol%” refers to a percentage when each constituent component (carboxylic acid component, alcohol component) in the polyester resin is defined as one unit (mol).

  On the other hand, the alcohol component is preferably an aliphatic diol. For example, ethylene glycol, 1,3-propanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 1,7-heptanediol, 1,8-octanediol, 1,9 -Nonanediol, 1,10-decanediol, 1,11-undecanediol, 1,12-dodecanediol, 1,13-tridecanediol, 1,14-tetradecanediol, 1,18-octadecanediol, 1,20 -Eicosanediol etc. are mentioned, However, it is not limited to these.

  The alcohol component preferably has an aliphatic diol component content of 80 constituent mol% or more, and may contain other components. As the alcohol component, the content of the aliphatic diol component is more preferably 90 constituent mol% or more.

  Examples of other components include constituent components such as a diol component having a double bond and a diol component having a sulfonic acid group.

  Examples of the diol having a double bond include 2-butene-1,4-diol, 3-hexene-1,6-diol, and 4-octene-1,8-diol. On the other hand, as the diol having a sulfonic acid group, 1,4-dihydroxy-2-sulfonic acid benzene sodium salt, 1,3-dihydroxymethyl-5-sulfonic acid benzene sodium salt, 2-sulfo-1,4-butane Examples include diol sodium salt.

  In the case where an alcohol component other than these linear aliphatic diol components is added (a diol component having a double bond or a diol component having a sulfonic acid group), the content in the alcohol component is from 1 to 20 mol%. It is preferably at most 2 mol% and more preferably at most 10 mol%.

  The method for producing the crystalline polyester resin is not particularly limited, and is produced by a general polyester polymerization method in which a carboxylic acid component and an alcohol component are reacted. Examples thereof include direct polycondensation and transesterification. Depending on the type, it will be manufactured separately. The molar ratio (acid component / alcohol component) when the acid component reacts with the alcohol component varies depending on the reaction conditions and the like, and cannot be generally stated, but is usually 1/1.

  The crystalline polyester resin is produced at a polymerization temperature of 180 ° C. or higher and 230 ° C. or lower, and reacted while removing water and alcohol generated during condensation. The reaction system may be reduced in pressure. When the monomer is not dissolved or compatible at the reaction temperature, a solvent having a high boiling point may be added as a solubilizer and dissolved. In the polycondensation reaction, the dissolution auxiliary solvent is distilled off. If a monomer with poor compatibility is present in the copolymerization reaction, the monomer with poor compatibility and the monomer and the carboxylic acid component or alcohol component to be polycondensed are condensed in advance and then polycondensed together with the main component. Good.

  Catalysts that can be used in the production of the crystalline polyester resin include alkali metal compounds such as sodium and lithium; alkaline earth metal compounds such as magnesium and calcium; zinc, manganese, antimony, titanium, tin, zirconium, germanium Metal compounds such as: phosphorous acid compounds, phosphoric acid compounds, and amine compounds. Specific examples include the following compounds.

  For example, sodium acetate, sodium carbonate, lithium acetate, calcium acetate, zinc stearate, zinc naphthenate, zinc chloride, manganese acetate, manganese naphthenate, titanium tetraethoxide, titanium tetrapropoxide, titanium tetraisopropoxide, titanium tetra Butoxide, antimony trioxide, triphenylantimony, tributylantimony, tin formate, tin oxalate, tetraphenyltin, dibutyltin dichloride, dibutyltin oxide, diphenyltin oxide, zirconium tetrabutoxide, zirconium naphthenate, zirconyl carbonate, zirconyl acetate, zirconyl stearate , Zirconyl octylate, germanium oxide, triphenyl phosphite, tris (2,4-di-t-butylphenyl) phosphite Ethyltriphenylphosphonium bromide, triethylamine, compounds such as triphenyl amine.

In addition to the above polymerizable monomer, a compound having a shorter chain alkyl group, alkenyl group, aromatic ring or the like may be used for the purpose of adjusting the melting temperature and molecular weight of the crystalline resin.
Specific examples include dicarboxylic acids, alkyl dicarboxylic acids such as succinic acid, malonic acid, and oxalic acid; phthalic acid, isophthalic acid, terephthalic acid, homophthalic acid, 4,4′-bibenzoic acid, and 2,6-naphthalene. Aromatic dicarboxylic acids such as dicarboxylic acid and 1,4-naphthalenedicarboxylic acid; and nitrogen-containing aromatic dicarboxylic acids such as dipicolinic acid, dinicotinic acid, quinolinic acid and 2,3-pyrazinedicarboxylic acid. In the case of diols, short chain alkyl diols such as succinic acid, malonic acid, acetone dicarboxylic acid, diglycolic acid and the like can be mentioned. In the case of short-chain alkyl vinyl polymerizable monomers, short-chain alkyls such as methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, butyl (meth) acrylate, alkenyl ( (Meth) acrylic acid esters; vinyl nitriles such as acrylonitrile and methacrylonitrile; vinyl ethers such as vinyl methyl ether and vinyl isobutyl ether; vinyl methyl ketone, vinyl ethyl ketone, vinyl isopropenyl ketones; ethylene, propylene, butadiene, Examples thereof include olefins such as isoprene. These polymerizable monomers may be used individually by 1 type, and may use 2 or more types together.

-Amorphous resin-
As the amorphous resin used in the present embodiment, a known amorphous binder resin for toner particles is used, and for example, a styrene-acrylic resin or a polyester resin can be used. As the amorphous resin, it is preferable to use an amorphous polyester resin.
The glass transition temperature (Tg) of the amorphous polyester resin is desirably in the range of 50 ° C. to 80 ° C., and more desirably in the range of 55 ° C. to 65 ° C. The weight average molecular weight is preferably in the range of 8000 to 30000, more preferably in the range of 8000 to 16000. Then, the third component may be copolymerized.
The amorphous polyester resin desirably has a common alcohol component or carboxylic acid component with the crystalline polyester resin used in combination with the amorphous polyester resin in order to increase the miscibility.

The method for producing the amorphous polyester resin is not particularly limited, and can be produced by a general polyester polymerization method as described above.
As the carboxylic acid component used for the synthesis of the amorphous polyester resin, various dicarboxylic acids mentioned for the crystalline polyester resin are used. As the alcohol component, various diols used for the synthesis of the amorphous polyester resin are used. For example, in addition to the aliphatic diols mentioned for the polyester resin, bisphenol A, bisphenol A ethylene oxide adduct, bisphenol A propylene oxide adduct, hydrogenated bisphenol A, bisphenol S, bisphenol S ethylene oxide adduct, bisphenol S propylene oxide An adduct or the like may be used.
Furthermore, it is particularly desirable to use bisphenol S derivatives such as bisphenol S, bisphenol S ethylene oxide adducts, and bisphenol S propylene oxide adducts from the viewpoint of manufacturability, heat resistance, and transparency of toner particles. Further, both the carboxylic acid component and the alcohol component may contain a plurality of components, and in particular, bisphenol S has an effect of improving heat resistance.
From the viewpoint of low-temperature fixability, the amorphous polyester resin preferably contains an aliphatic component in at least one of the alcohol component and the carboxylic acid component.

From the viewpoint of low-temperature fixability, it is more preferable that at least one of the alcohol component and the carboxylic acid component contains an aliphatic component as the polyester resin of either the crystalline polyester resin or the amorphous polyester resin. Moreover, it is more preferable that an aliphatic component is included in at least one of the alcohol component and the carboxylic acid component from the viewpoint of enhancing the plasticizing effect of the specific paraffin oil on the binder resin.
From the viewpoint of improving the low-temperature fixability, it is more preferable that at least one of the alcohol component and the carboxylic acid component is only a polyester resin containing an aliphatic component. Specifically, the polyester resin of both the amorphous polyester resin and the crystalline polyester resin used in combination therewith may contain an aliphatic component in at least one of the alcohol component and the carboxylic acid component. preferable.

From the viewpoint of further improving the low-temperature fixability, the polyester resin includes, for example, an aliphatic dicarboxylic acid (including an acid anhydride or a lower acid (for example, an alkyl ester having 1 to 5 carbon atoms) alkyl ester). More preferably, it is a polycondensate of the component and an alcohol component containing an aliphatic diol.
From the same viewpoint, a polycondensate of a carboxylic acid component containing an aliphatic dicarboxylic acid having 6 to 16 carbon atoms and containing an carboxy group carbon and an alcohol component containing an aliphatic diol having 4 to 14 carbon atoms. Is more preferable. Furthermore, a polycondensate of a carboxylic acid component containing an aliphatic dicarboxylic acid having 8 to 14 carbon atoms and containing an carboxy carbon and an alcohol component containing an aliphatic diol having 4 to 8 carbon atoms is particularly preferred.

Next, the amorphous resin used as the binder resin, the crosslinking treatment of the crystalline resin, and the copolymer components that can be used in the synthesis of the binder resin will be described.
In synthesizing the binder resin, other components may be copolymerized or a compound having a hydrophilic polar group may be used.
As a specific example, when the binder resin is a polyester resin, a dicarboxylic acid compound in which an aromatic ring such as sulfonyl-terephthalic acid sodium salt or 3-sulfonylisophthalic acid sodium salt is directly substituted is used. When the binder resin is a vinyl resin, unsaturated aliphatic carboxylic acids such as (meth) acrylic acid and itaconic acid, glycerin mono (meth) acrylate, fatty acid-modified glycidyl (meth) acrylate, zinc mono (meth) acrylate, Zinc di (meth) acrylate, 2-hydroxyethyl (meth) acrylate, polyethylene glycol (meth) acrylate, esters of (meth) acrylic acid such as polypropylene glycol (meth) acrylate and alcohols, ortho, meta, para position Examples thereof include styrene derivatives having a sulfonyl group, sulfonyl group-substituted aromatic vinyl such as sulfonyl group-containing vinyl naphthalene, and the like.

Further, a crosslinking agent may be added to the binder resin.
Specific examples of the crosslinking agent include aromatic polyvinyl compounds such as divinylbenzene and divinylnaphthalene; divinyl phthalate, divinyl isophthalate, divinyl terephthalate, divinyl homophthalate, divinyl trimesate / trivinyl, divinyl naphthalenedicarboxylate, Polyvinyl esters of aromatic polyvalent carboxylic acids such as divinyl biphenyl carboxylate; divinyl esters of nitrogen-containing aromatic compounds such as divinyl pyridinedicarboxylate; unsaturated heterocyclic compounds such as pyrrole and thiophene; Vinyl esters of unsaturated heterocyclic compounds such as vinyl furan carboxylate, vinyl pyrrole-2-carboxylate, vinyl thiophene carboxylate; butanediol methacrylate, hexanediol acrylate, octanediol meta (Meth) acrylic acid esters of linear polyhydric alcohols such as relates, decanediol acrylates, dodecanediol methacrylates; branches such as neopentyl glycol dimethacrylate, 2-hydroxy, 1,3-diacryloxypropane, (Meth) acrylic acid esters of polyhydric alcohols; polyethylene glycol di (meth) acrylate, polypropylene polyethylene glycol di (meth) acrylates; divinyl succinate, divinyl fumarate, vinyl / divinyl maleate, divinyl diglycolate, itaconic acid Vinyl / divinyl, acetone dicarboxylate divinyl, glutarate divinyl, 3,3′-thiodipropionate divinyl, trans-aconite divinyl / trivinyl, adipate divinyl, pimelate divinyl, Belin acid divinyl azelate, divinyl sebacate, divinyl dodecanedioate divinyl, the polyvinyl esters of polycarboxylic acids such as oxalic acid divinyl and the like.

  In particular, in crystalline polyester resins, unsaturated polycarboxylic acids such as fumaric acid, maleic acid, itaconic acid, and trans-aconitic acid are copolymerized in the polyester, and then multiple bond portions in the resin, or You may use the method of bridge | crosslinking using another vinyl type compound. In this embodiment, these crosslinking agents may be used individually by 1 type, and may be used in combination of 2 or more types.

  As a method of cross-linking with these cross-linking agents, a method of polymerizing and cross-linking with a cross-linking agent when polymerizing a polymerizable monomer (monomer) may be used. Alternatively, the unsaturated portion may be left in the binder resin, and after the binder resin is polymerized or after the toner particles are produced, the unsaturated portion may be crosslinked by a crosslinking reaction.

  When the binder resin is a polyester resin, it can be obtained by polycondensation of a polymerizable monomer. As the polycondensation catalyst, known catalysts are used, and specific examples thereof include titanium tetrabutoxide, dibutyltin oxide, germanium dioxide, antimony trioxide, tin acetate, zinc acetate, tin disulfide and the like. When the binder resin is a vinyl resin, it can be obtained by radical polymerization of a polymerizable monomer.

  The initiator for radical polymerization is not particularly limited as long as it can undergo emulsion polymerization. Specifically, hydrogen peroxide, acetyl peroxide, cumyl peroxide, tert-butyl peroxide, propionyl peroxide, benzoyl peroxide, chlorobenzoyl peroxide, dichlorobenzoyl peroxide, bromomethylbenzoyl peroxide, lauroyl peroxide , Ammonium persulfate, sodium persulfate, potassium persulfate, diisopropyltetralin hydroperoxide, 1-phenyl-2-methylpropyl-1-hydroperoxide, pertriphenylacetic acid-tert-butyl hydroperoxide, tert-butyl formate, Peroxides such as tert-butyl peracetate, tert-butyl perbenzoate, tert-butyl perphenylacetate, tert-butyl permethoxyacetate, tert-butyl perN- (3-toluyl) carbamate, 2,2 '-Azobisp Bread, 2,2′-dichloro-2,2′-azobispropane, 1,1′-azo (methylethyl) diacetate, 2,2′-azobis (2-amidinopropane) hydrochloride, 2,2 ′ -Azobis (2-amidinopropane) nitrate, 2,2'-azobisisobutane, 2,2'-azobisisobutyramide, 2,2'-azobisisobutyronitrile, 2,2'-azobis-2- Methyl methylpropionate, 2,2′-dichloro-2,2′-azobisbutane, 2,2′-azobis-2-methylbutyronitrile, dimethyl 2,2′-azobisisobutyrate, 1,1′-azobis (1 -Sodium methylbutyronitrile-3-sulfonate), 2- (4-methylphenylazo) -2-methylmalonodinitrile, 4,4'-azobis-4-cyanovaleric acid, 3,5-dihy Roxymethylphenylazo-2-methylmalonodinitrile, 2- (4-bromophenylazo) -2-allylmalonodinitrile, 2,2′-azobis-2-methylvaleronitrile, 4,4′-azobis-4 -Dimethyl cyanovalerate, 2,2'-azobis-2,4-dimethylvaleronitrile, 1,1'-azobiscyclohexanenitrile, 2,2'-azobis-2-propylbutyronitrile, 1,1'- Azobis-1-chlorophenylethane, 1,1′-azobis-1-cyclohexanecarbonitrile, 1,1′-azobis-1-cycloheptanenitrile, 1,1′-azobis-1-phenylethane, 1,1 ′ -Azobiscumene, 4-nitrophenylazobenzyl cyanoacetate ethyl, phenylazodiphenylmethane, phenylazotriphenylmeth Tan, 4-nitrophenylazotriphenylmethane, 1,1′-azobis-1,2-diphenylethane, poly (bisphenol A-4,4′-azobis-4-cyanopentanoate), poly (tetraethylene glycol) -2,2'-azobisisobutyrate) and the like, 1,4-bis (pentaethylene) -2-tetrazene, 1,4-dimethoxycarbonyl-1,4-diphenyl-2-tetrazene and the like Can be mentioned. These polymerization initiators are also used as initiators in the crosslinking reaction.

  In addition, although description mainly focused on the crystalline polyester resin and the amorphous polyester resin as the binder resin, other styrenes such as styrene, parachlorostyrene, and α-methylstyrene; methyl acrylate, acrylic Acrylic monomers such as ethyl acrylate, n-propyl acrylate, butyl acrylate, lauryl acrylate, 2-ethylhexyl acrylate; methyl methacrylate, ethyl methacrylate, n-propyl methacrylate, lauryl methacrylate, methacrylic acid Methacrylic monomers such as 2-ethylhexyl; Further, ethylenically unsaturated acid monomers such as acrylic acid, methacrylic acid and sodium styrenesulfonate; Vinylnitriles such as acrylonitrile and methacrylonitrile; Vinylmethyl ether, vinyl Isobutyl ether, etc. Vinyl ethers; Vinyl ketones such as vinyl methyl ketone, vinyl ethyl ketone, and vinyl isopropenyl ketone; Homopolymers of olefin monomers such as ethylene, propylene, and butadiene; Copolymers combining two or more of these monomers Or a mixture thereof, and further, an epoxy resin, a polyester resin, a polyurethane resin, a polyamide resin, a cellulose resin, a polyether resin, etc., a non-vinyl condensation resin, or a mixture of them with the vinyl resin, these A graft polymer obtained by polymerizing a vinyl monomer in the coexistence may be used.

  As will be described later, when the toner particles of the present embodiment are produced by the emulsion polymerization aggregation method, the resin is prepared as a resin particle dispersion. The resin particle dispersion can be easily obtained by an emulsion polymerization method and a similar polymerization method in a heterogeneous dispersion system. Further, it can be obtained by any method such as a method in which a polymer polymerized in advance by a solution polymerization method, a cage polymerization method or the like is added to a solvent in which the polymer does not dissolve together with a stabilizer and mechanically mixed and dispersed.

For example, when a vinyl monomer is used, an ionic surfactant or the like is used. Desirably, resin particles are obtained by emulsion polymerization or seed polymerization using an ionic surfactant and a nonionic surfactant in combination. Dispersions can be made.
Surfactants include sulfate, salt, phosphate, and soap anionic surfactants; amine and quaternary ammonium salt and other cationic surfactants; polyethylene glycols Nonionic surfactants such as alkylphenol ethylene oxide adduct system, alkyl alcohol ethylene oxide adduct system, and polyhydric alcohol system, and various graft polymers are not particularly limited.

  When preparing a resin particle dispersion by emulsion polymerization, a protective colloid is added to the particle surface by adding an unsaturated acid such as acrylic acid, methacrylic acid, maleic acid, or styrene sulfonic acid as a part of the monomer component. This is particularly desirable because a layer is formed and soap-free polymerization can be performed.

  The volume average particle diameter of the resin particles is desirably 1 μm or less, and more desirably 0.01 μm or more and 1 μm or less. The average particle diameter of the resin particles is measured using a laser diffraction particle size distribution measuring device (SALD2000A, manufactured by Shimadzu Corporation).

  In addition, a weight average molecular weight and a number average molecular weight are values measured by GPC (gel permeation chromatography). “HLC-8120GPC, SC-8020 (manufactured by Tosoh Corporation)” is used as the GPC apparatus, two columns “TSKgel, SuperHM-H (6.0 mm ID × 15 cm, manufactured by Tosoh Corporation)” are used, and THF (tetrahydrofuran) is used as the eluent. ) Is used. As experimental conditions, an experiment is performed using a sample concentration of 0.5%, a flow rate of 0.6 ml / min, a sample injection amount of 10 μl, a measurement temperature of 40 ° C., and a RI (Refractive Index) detector. The calibration curve is “polystylen standard sample TSK standard” manufactured by Tosoh Corporation: “A-500”, “F-1”, “F-10”, “F-80”, “F-380”, “A-2500”. ”,“ F-4 ”,“ F-40 ”,“ F-128 ”, and“ F-700 ”.

-Release agent-
The release agent used in the present embodiment includes low molecular weight polyolefins such as polyethylene, polypropylene, and polybutene; fatty acid amides such as silicones, oleic acid amide, erucic acid amide, ricinoleic acid amide, and stearic acid amide; carnauba wax Plant waxes such as beeswax, rice wax, candelilla wax, tree wax, Liliba oil; animal waxes such as beeswax; minerals such as montan wax, ozokerite, ceresin, paraffin wax, microcrystalline wax, Fischer-Tropsch wax, petroleum And their modified products.

When toner particles are prepared using an emulsion polymerization aggregation method, these release agents are also dispersed in water together with a polymer electrolyte such as an ionic surfactant, a polymer acid, and a polymer base. And it heats more than melting | fusing temperature, and it granulates using the homogenizer which can give strong shearing force, or a pressure discharge type | mold disperser, and uses it as a mold release agent particle dispersion liquid containing a mold release agent particle with an average particle diameter of 1 micrometer or less. May be.
These release agent particles may be added to the mixed solvent at a time together with other resin particle components in the production of toner particles, or may be divided and added in multiple stages.

  The addition amount of these release agents is desirably in the range of 0.5% by mass or more and 50% by mass or less with respect to the entire toner particles. More desirably, it is in the range of 1 to 30% by mass, and more desirably in the range of 5 to 15% by mass.

In addition, the average dispersion diameter of the release agent dispersed and contained in the toner particles of the exemplary embodiment is preferably in the range of 0.3 μm to 0.8 μm, and in the range of 0.4 μm to 0.8 μm. It is more desirable to be within.
Further, the standard deviation of the dispersion diameter of the release agent is desirably 0.05 or less, and more desirably 0.04 or less.
The average dispersion diameter of the release agent dispersed and contained in the toner particles was determined by analyzing a TEM (Transmission Electron Microscope) photograph with an image analysis device (Lusex image analysis device manufactured by Nireco) and 100 toners. The average value of the dispersion diameter (= (major axis + minor axis) / 2) of the release agent in the particles is obtained, and the standard deviation is obtained based on the individual dispersion diameters obtained at this time.

Further, the exposure rate of the release agent on the toner particle surface is preferably in the range of 5 atom% to 12 atom%, and more preferably in the range of 6 atom% to 11 atom%.
Here, the exposure rate is obtained by XPS (X-ray photoelectron spectroscopy) measurement. As an XPS measuring apparatus, JPS-9000MX manufactured by JEOL Ltd. is used, and measurement is performed using an MgKα ray as an X-ray source, setting an acceleration voltage to 10 kV, and an emission current to 30 mA. Here, the amount of the release agent on the toner particle surface is quantified by the peak separation method of the C1S spectrum. In the peak separation method, the measured C1S spectrum is separated into components using curve fitting by the least square method. As a component spectrum that is a base for separation, a C1S spectrum obtained by independently measuring a release agent, a binder resin, and a crystalline resin used for the production of toner particles is used.

-Colorant-
Examples of the colorant used in the present embodiment include carbon black, chrome yellow, hansa yellow, benzidine yellow, sren yellow, quinoline yellow, permanent orange GTR, pyrazolone orange, vulcan orange, watch young red, permanent red, brilliant carmine 3B, Brilliant Carmine 6B, Dupont Oil Red, Pyrazolone Red, Rizor Red, Rhodamine B Lake, Lake Red C, Rose Bengal, Aniline Blue, Ultramarine Blue, Calco Oil Blue, Methylene Blue Chloride, Phthalocyanine Blue, Phthalocyanine Green, Malachite Green Oxalate, etc. Various pigments, acridine, xanthene, azo, benzoquinone, azine, anthraquinone , Thioindico, dioxazine, thiazine, azomethine, indico, phthalocyanine, aniline black, polymethine, triphenylmethane, diphenylmethane, thiazole, etc. Can be used.

  When toner particles are prepared using an emulsion polymerization aggregation method, these colorants are also dispersed in a solvent and used as a colorant particle dispersion. In this case, the volume average particle diameter of the colorant particles is desirably 0.8 μm or less, and more desirably 0.05 μm or more and 0.5 μm or less.

Further, the proportion of coarse particles having a volume average particle diameter of 0.8 μm or more in the colorant particle dispersion is preferably less than 10% by number, preferably 0% by number, and the average particle diameter in the colorant particle dispersion is 0.00. The existence ratio of particles of 05 μm or less is desirably 5% by number or less.
The volume average particle diameter of the colorant particles is also measured using a laser diffraction type particle size distribution measuring apparatus (manufactured by Shimadzu Corporation, SALD2000A). The amount of the colorant added is preferably set in the range of 1% by mass to 20% by mass with respect to the entire toner particles.

  As a method for dispersing these colorants in a solvent, any method such as a rotary shearing homogenizer, a ball mill having a medium, a sand mill, or a dyno mill may be used without any limitation.

In addition, a colorant that has been surface-modified with rosin, polymer, or the like can also be used. The colorant subjected to the surface modification treatment is stabilized in the colorant particle dispersion, and after the colorant is dispersed to the average particle size required in the colorant particle dispersion, the resin particle dispersion and During mixing, it is advantageous in that the colorants do not aggregate in the aggregation step and the like, and a good dispersion state can be maintained.
Examples of the polymer used for the surface treatment of the colorant include acrylonitrile polymer and methyl methacrylate polymer.

  The conditions for surface modification are generally a polymerization method in which a monomer is polymerized in the presence of a colorant (pigment), a colorant (pigment) is dispersed in a polymer solution, and the solubility of the polymer is lowered to reduce the colorant (pigment). ) A phase separation method that precipitates on the surface is used.

-Other additive components-
When the toner particles of this embodiment are used as magnetic toner particles, magnetic powder is included. Examples of the magnetic powder include magnetic oxides such as ferrite and magnetite; magnetic metals such as reduced iron, cobalt, nickel, and manganese; alloys or compounds containing these magnetic metals. Furthermore, various commonly used charge control agents such as quaternary ammonium salts, nigrosine compounds and triphenylmethane pigments may be added.

  The toner particles of the present embodiment may contain inorganic particles. Inorganic particles having a central particle size of 5 nm to 30 nm and inorganic particles having a central particle size of 30 nm to 100 nm may be contained in a range of 0.5% by mass to 10% by mass with respect to the toner. More desirable in terms of durability.

  As the inorganic particles, silica, hydrophobized silica, titanium oxide, alumina, calcium carbonate, magnesium carbonate, tricalcium phosphate, colloidal silica, cationic surface-treated colloidal silica, anion surface-treated colloidal silica, or the like is used. These inorganic particles are dispersed in advance in the presence of an ionic surfactant using an ultrasonic disperser or the like, and it is more desirable to use colloidal silica that does not require this dispersion treatment.

  In addition, a known external additive may be externally added to the toner particles of this embodiment. As the external additive, inorganic particles such as silica, alumina, titania, calcium carbonate, magnesium carbonate, and tricalcium phosphate are used. For example, as fluidity aids and cleaning aids, inorganic particles such as silica, alumina, titania and calcium carbonate, and resin particles such as vinyl resin, polyester resin and silicone resin are used. The method for adding the external additive is not particularly limited, but may be added to the toner particle surface by applying a shearing force in a dry state.

Next, the production of the toner particles of this embodiment will be described.
The toner according to the exemplary embodiment may be manufactured by any known toner manufacturing method. In particular, a so-called wet manufacturing method, that is, a binder resin and a colorant are used in water or an organic solvent or a mixed solvent thereof. In order to control the elemental composition on the surface of the toner particles, it is desirable that the toner particles are manufactured through a granulation step for granulating the colored particles and a washing / drying step for washing / drying the colored particles.

  In such a wet manufacturing method, a colorant, a release agent, other components, etc. are suspended together with a polymerizable monomer that forms a binder resin such as an amorphous resin, and the polymerizable monomer is polymerized. A toner constituent material such as a turbid polymerization method, a compound having an ionic dissociation group, a binder resin, a colorant, and a release agent is dissolved in an organic solvent and dispersed in an aqueous solvent in a suspended state. Dissolving suspension method to be removed, emulsion resin aggregation method in which binder resin component such as amorphous resin is produced by emulsion polymerization, heteroaggregated with dispersion liquid of pigment, release agent, etc., and then fused and united Although it is mentioned, it is not limited to these. Among these, the emulsion polymerization aggregation method is optimal because of excellent particle size controllability, narrow particle size distribution, shape controllability, narrow shape distribution, internal dispersion controllability, and the like of the toner particles.

  When the emulsion polymerization aggregation method is used, the toner particles of the present embodiment include, for example, a resin particle dispersion in which a binder resin such as an amorphous resin or a crystalline resin is dispersed, and a colorant particle dispersion in which a colorant is dispersed. In the raw material dispersion obtained by mixing the liquid and the release agent particle dispersion in which the release agent is dispersed, and in the raw material dispersion in which the aggregated particles are formed, It can be manufactured through at least a fusion step in which the aggregated particles are fused by heating to a temperature equal to or higher than the glass transition temperature (or the melting temperature of the crystalline resin). In addition, you may add other dispersion liquids, such as an inorganic particle dispersion liquid, to a raw material dispersion liquid. In particular, when an inorganic particle dispersion having a hydrophobic surface is added, the dispersibility of the release agent and crystalline resin inside the toner particles can be controlled by the degree of hydrophobicity.

Hereinafter, the method for producing toner particles of the present embodiment will be described in more detail using an emulsion polymerization aggregation method as a specific example.
When the toner particles of the present embodiment are produced by an emulsion polymerization aggregation method, the toner particles are produced through at least an aggregation step and a fusion step, and are formed on the surface of the aggregated particles (core particles) formed through the aggregation step. You may provide the adhesion process which forms the aggregated particle which has the core-shell structure to which the resin particle was made to adhere.

-Aggregation process-
In the aggregation step, a resin particle dispersion in which a binder resin such as an amorphous resin or a crystalline resin is dispersed (in addition, an amorphous resin or a crystalline resin may be prepared as separate dispersions. ) And a colorant particle dispersion liquid in which a colorant is dispersed and a release agent particle dispersion liquid in which a release agent is dispersed to form aggregated particles.
Specifically, the raw material dispersion obtained by mixing various dispersions is heated to form aggregated particles in which the particles in the raw material dispersion are aggregated. The heating is performed at a temperature lower than the glass transition temperature of the amorphous resin. A desirable temperature range is a range below 5 ° C to 25 ° C.

Agglomerated particles are formed by adding a flocculant at room temperature (23 ° C.) while stirring with a rotary shearing homogenizer to make the pH of the raw material dispersion acidic.
As the aggregating agent used in the aggregating step, a surfactant having a reverse polarity to the surfactant used as a dispersing agent added to the raw material dispersion, that is, an inorganic metal salt, or a metal complex having a valence of 2 or more is preferably used. . In particular, the use of a metal complex is particularly desirable because the amount of the surfactant used is reduced and the charging characteristics are improved.

  Examples of the inorganic metal salt include metal salts such as calcium chloride, calcium nitrate, barium chloride, magnesium chloride, zinc chloride, aluminum chloride, and aluminum sulfate, and polyaluminum chloride, polyaluminum hydroxide, and calcium polysulfide. Examples thereof include inorganic metal salt polymers. Of these, aluminum salts and polymers thereof are particularly preferred. In order to obtain a sharper particle size distribution (narrow particle size distribution), the valence of the inorganic metal salt is bivalent than monovalent, trivalent than bivalent, tetravalent than trivalent, and the same valence. Even if it exists, the polymerization type inorganic metal salt polymer is more suitable.

In the present embodiment, the inorganic metal salt is used as an inorganic particle dispersion in the agglomeration step in order to control the abundance ratio of the Group IIA element, Group IIIB element and Group IVB element (excluding carbon). It is desirable to add and agglomerate things. This effectively acts on the molecular chain terminal of the binder resin and contributes to the formation of a crosslinked structure.
The inorganic particle dispersion is prepared by the method described above for the colorant particle dispersion and the like, and the dispersion average particle diameter of the inorganic particles is preferably in the range of 100 nm to 500 nm.

  In the aggregation process, the inorganic particle dispersion may be added stepwise or continuously. These methods are effective to achieve the abundance ratio from the toner particle surface to the inside. When adding stepwise, it is particularly desirable to add the dispersion at a slow rate of 0.1 g / min or less when adding continuously in three steps or more.

  The amount of the inorganic particle dispersion added varies depending on the type of metal required and the degree of formation of the crosslinked structure, but is in the range of 0.5 to 10 parts by mass with respect to 100 parts by mass of the binder resin component. Desirably, the range of 1 part by mass to 5 parts by mass is more desirable.

  After passing through the aggregation process, an adhesion process may be performed. In the attaching step, the coating layer is formed by attaching resin particles to the surface of the aggregated particles formed through the above-described aggregation step. Thus, toner particles having a so-called core layer and a core-shell structure covering the core layer are obtained.

  The coating layer is usually formed by additionally adding a dispersion containing amorphous resin particles to the dispersion in which aggregated particles (core particles) are formed in the aggregation step. The amorphous resin used in the adhesion process may be the same as or different from that used in the aggregation process.

  In general, the adhesion step is used in the case of producing toner particles having a core-shell structure in which a crystalline resin as a main component is contained as a binder resin together with a release agent, and the main purpose thereof is the core layer. The purpose is to suppress the exposure of the release agent and crystalline resin contained on the surface of the toner particles and to supplement the strength of the toner particles.

-Fusion process-
In the fusion step performed after the aggregation step or the aggregation step and the adhesion step, the pH of the suspension containing the aggregated particles formed through these steps is set to a necessary range, thereby the progress of the aggregation. After stopping, the aggregated particles are fused by heating.
Note that the abundance ratio of the Group IA element (excluding hydrogen) is controlled in a desirable range by the aim of the pH value at this time.

The pH is adjusted by adding an acid or an alkali. The acid is not particularly limited, but an aqueous solution of 0.1% to 50% of an inorganic acid such as hydrochloric acid, nitric acid or sulfuric acid is desirable. The alkali is not particularly limited, but an aqueous solution of 0.1% to 50% of an alkali metal hydroxide such as sodium hydroxide or potassium hydroxide is desirable. In the adjustment of pH, when a local pH change occurs, local aggregated particles themselves are destroyed and local excessive aggregation occurs, and the shape distribution is also deteriorated. In particular, the larger the scale, the greater the amount of acid and alkali. In general, there is only one place where the acid and alkali are added, so that if the treatment is performed for the same time, the concentration of acid and alkali at the place where the scale is increased becomes higher.
In order for the ratio of the Group IA element (excluding hydrogen) to be within the range of the present embodiment, the pH is desirably in the range of 6.0 to 8.0, and is in the range of 6.5 to 7.5. It is more desirable to set the range.

After performing the above composition control, the aggregated particles are heated and fused and united. And in this heating, each element and the molecular chain terminal of the resin react to form a crosslinked structure.
In the fusion, the aggregated particles are fused by heating at a temperature equal to or higher than the glass transition temperature of the amorphous resin (or the melting temperature of the crystalline resin).

The cross-linking reaction may be performed by other components during the heating during the fusion or after the fusion is completed. Moreover, you may perform a crosslinking reaction with fusion. When the crosslinking reaction is performed, the above-described crosslinking agent and polymerization initiator are used in the production of toner particles.
The polymerization initiator may be preliminarily mixed with the dispersion at the stage of preparing the raw material dispersion, or may be incorporated into the aggregated particles in the aggregation process. Further, it may be introduced after the fusion step or after the fusion step. In the case of introduction after the aggregation step, the adhesion step, the fusion step, or the fusion step, a solution in which the polymerization initiator is dissolved or emulsified is added to the dispersion. These polymerization initiators may be added with known crosslinking agents, chain transfer agents, polymerization inhibitors and the like for the purpose of controlling the degree of polymerization.

-Cleaning, drying process, etc.-
After completion of the coalescing and coalescing step of the aggregated particles, a washing step, a solid-liquid separation step, a drying step, and the like may be performed, and toner particles required through these steps are obtained. In the washing process, it is desirable to perform substitution washing with ion-exchanged water in consideration of chargeability. Moreover, although there is no restriction | limiting in particular in a solid-liquid separation process, From the point of productivity, suction filtration, pressure filtration, etc. are suitable. Further, the drying process is not particularly limited, but freeze drying, flash jet drying, fluidized drying, vibration fluidized drying and the like are desirably used from the viewpoint of productivity. Various external additives may be added to the toner particles after drying.

  Further, the volume average particle diameter D50v of the toner particles of the present embodiment is preferably in the range of 0.1 μm to 10 μm, and more preferably in the range of 0.5 μm to 4 μm.

  The volume average particle size distribution index GSDv of the toner particles is preferably 1.28 or less. On the other hand, the number average particle size distribution index GSDp is preferably 1.30 or less. More preferably, the volume average particle size distribution index GSDv is 1.25 or less, and the number average particle size distribution index GSDp is 1.25 or less.

Here, in this embodiment, the volume average particle diameter D50v and various particle size distribution indices are, for example, a multisizer 4e type (manufactured by Beckman-Coulter), and the electrolyte is ISOTON-II (manufactured by Beckman-Coulter). Measured using. In the measurement, 0.5 mg to 50 mg of a measurement sample is added to 2 ml of a 5% aqueous solution of a surfactant, preferably sodium alkylbenzenesulfonate as a dispersant, and this is added to 100 ml to 150 ml of an electrolytic solution.
The electrolyte in which the sample is suspended is subjected to a dispersion treatment with an ultrasonic disperser for 1 minute, and with the multisizer 4e type, an aperture diameter suitable for the measured particle diameter (10 μm to 100 μm) is used. Measure the particle size distribution of particles in the range of 0.2 μm to 60 μm. The number of particles to be sampled is 50,000.

For the particle size range (channel) divided based on the particle size distribution measured in this way, the cumulative distribution is drawn from the small diameter side for the volume and number, respectively, and the particle size that becomes 16% is the cumulative volume average particle size D16v, Cumulative number average particle size D16p, cumulative 50% cumulative particle size average particle size D50v, cumulative number average particle size D50p, cumulative particle size 84% cumulative volume average particle size D84v, cumulative number average particle size D84p. It is defined as
Using these, the volume average particle size distribution index (GSDv) is obtained by the equation (D84v / D16v) ^1/2 and the number average particle size distribution index (GSDp) is obtained by the equation (D84p / D16p) ^1/2 .

  Furthermore, the average circularity is desirably in the range of 0.940 to 0.980, and more desirably in the range of 0.950 to 0.970.

  The average circularity of the toner particles is measured by a flow type particle image analyzer FPIA-2000 (manufactured by Toa Medical Electronics Co., Ltd.). As a specific measurement method, a surfactant, preferably an alkylbenzene sulfonate, is added in an amount of 0.1 to 0.5 ml as a dispersant in 100 to 150 ml of water from which impure solids have been previously removed, and a measurement sample is further added. Add in the range of 0.1 g to 0.5 g. The suspension in which the measurement sample is dispersed is subjected to a dispersion treatment for 1 to 3 minutes with an ultrasonic disperser, and the dispersion liquid concentration is set to 30 million particles / μl or more and 10,000 particles / μl or less, and the average circularity of the toner particles is determined by the apparatus. taking measurement.

  The glass transition temperature (Tg) of the toner particles of this embodiment is not particularly limited, but a range of 40 ° C. or higher and 90 ° C. or lower is preferably selected.

  In addition, a glass transition temperature (Tg) is measured based on ASTMD3418-8, for example using a DSC measuring machine (Differential scanning calorimeter DSC-7, Perkin-Elmer company make). The temperature correction of the detection unit of the apparatus uses the melting temperature of indium and zinc, and the correction of heat quantity uses the heat of fusion of indium. As the sample, an aluminum pan is used, an empty pan is set as a control, and the measurement is performed at a heating rate of 10 ° C./min.

[Carrier liquid]
Next, the carrier liquid in the present embodiment will be described in detail.

In the liquid developer according to the exemplary embodiment, the carrier liquid may be either nonvolatile or volatile, but is preferably a nonvolatile carrier liquid.
In the liquid developer of this embodiment, non-volatile means that the flash point is 130 ° C. or higher, or the volatile content after 24 hours at 150 ° C. is 8% by mass or less. The flash point is measured according to JIS K2265-4 (2007).

  Examples of the component constituting the carrier liquid include silicone oil such as dimethyl silicone oil, paraffin oil, vegetable oil and the like, and these may be used alone or in combination of two or more. Among these, it is preferable to use silicone oil.

  When using silicone oil, it is good to contain in the range of 50 mass% or more with respect to the whole carrier liquid, for example. The silicone oil content is preferably in the range of 80% by mass or more and 100% by mass or less with respect to the total amount of the carrier liquid in terms of having low-temperature fixability and suppressing image omission, and 90% by mass or more. The content is more preferably in the range of 100% by mass or less, further preferably in the range of 95% by mass or more and 100% by mass or less, and particularly preferably in the range of 100% by mass.

In addition, when a non-volatile carrier liquid is comprised only from silicone oil (that is, when silicone oil contains 100 mass% with respect to the whole carrier liquid), silicone oil corresponds to a carrier liquid.
When the carrier liquid is composed of silicone oil and other carrier liquids other than, for example, silicone oil, a mixture of silicone oil and other carrier liquids other than silicone oil corresponds to the carrier liquid.

Examples of the silicone oil include dimethyl silicone oil (commercially available from Shin-Etsu Chemical Co., KF-96, KF-965, KF-968; Toray Dow Corning, SH200; Momentive Performance Materials, TSF451). Etc.), methyl hydrogen silicone oil (manufactured by Shin-Etsu Chemical Co., Ltd., KF-99, etc.), methyl phenyl silicone oil (manufactured by Shin-Etsu Chemical Co., Ltd., KF-50, KF-54, etc.) and the like.
These silicone oils may be used alone or in combination of two or more.

An example of the non-volatile silicone oil as the silicone oil is, for example, KF-96 (kinematic viscosity of 10 mm ² / s or more) manufactured by Shin-Etsu Chemical Co., Ltd., SH200 (dynamic viscosity of 10 mm) manufactured by Toray Dow Corning. ² / s or higher), Momentive Performance Materials, TSF451 (kinematic viscosity of 10 mm ² / s or higher), and the like.

(Other carrier liquids)
In addition, the carrier liquid may contain other carrier liquids as needed, as long as the effects such as low-temperature fixability and suppression of image omission are not impaired. Other carrier liquids include, for example, polyol compounds such as ethylene glycol, diethylene glycol, and propylene glycol; aliphatic hydrocarbon solvents such as paraffin oil (commercially available, MORESCO, Moresco White P-40, Moresco White P-55, Moresco White P-70, Moresco White P-100, Moresco White P-200, Moresco White P-350P, Exxon Chemical Corporation Isopar L, Isopar M, etc.); Carbonization of naphthenic oils, etc. Hydrogen-based solvent (commercially available: Exxon Chemical Co., Exol D80, Exol D110, Exol D130, Nippon Petrochemical Co., Ltd., Naphthezol L, Naphthezol M, Naphthezol H, New Naphthezol 160, New Naphthezol 200, New Naphthezol 20, New NAPHTESOL MS-20P, etc.); an aromatic compound such as toluene. Besides these, cyclohexane, tetrahydrofuran, acetone, 2-butanol and the like can be mentioned. When these components are contained, they may be contained in an amount of less than 50% by mass with respect to the whole carrier liquid, as long as the effect on properties such as low-temperature fixability and suppression of image omission is not impaired. The content is preferably less than 5% by mass, and more preferably less than 5% by mass.
However, other carrier liquids are not contained (ie, 0 mass) in terms of characteristics such as low-temperature fixability and suppression of image omission, and further in terms of suppressing film deformation when an image is formed on a thermoplastic resin film. %). These components may be either nonvolatile or volatile components, but are preferably nonvolatile from the same point.

[Specific polyhydric alcohol ester compound]
Hereinafter, the specific polyhydric alcohol ester compound will be described in detail.
The liquid developer of this embodiment contains a specific polyhydric alcohol ester compound in the carrier liquid. The specific polyhydric alcohol ester compound is a reaction product of a linear or branched saturated aliphatic polyhydric alcohol and a linear or branched saturated aliphatic monovalent carboxylic acid.
In the present embodiment, the saturated aliphatic monovalent carboxylic acid includes a form of a lower alkyl ester of a saturated aliphatic monovalent carboxylic acid.

  The specific polyhydric alcohol ester compound can be produced by a known general method. For example, a method in which the polyhydric alcohol and the monovalent carboxylic acid are subjected to a dehydration condensation reaction can be given. Moreover, for example, a method of reacting the above polyhydric alcohol and the above monovalent carboxylic acid alkyl ester having 1 to 5 carbon atoms by a transesterification method may be mentioned.

  The polyhydric alcohol is represented by the following general formula (1). The monovalent carboxylic acid is represented by the following general formula (2). And the specific polyhydric alcohol ester compound which is these reaction products is represented by following General formula (3).

In the general formula (1), R ¹ represents a residue obtained by removing a hydroxyl group from a linear or branched saturated aliphatic polyhydric alcohol. n represents an integer of 2 or more (preferably an integer of 2 or more and 8 or less, more preferably an integer of 3 or more and 6 or less).

In general formula (2), R ² represents a residue obtained by removing a carboxy group from a linear or branched saturated aliphatic carboxylic acid (or a residue obtained by removing an ester group from a saturated aliphatic carboxylic acid ester). . R ³ represents a hydrogen atom or a lower alkyl group having 1 to 5 carbon atoms.

In the general formula (3), ^{R 1} and ^{R 2} represents the general formula (1) ^{R 1,} and the formula in the (2) the same group as ^{R 2} in. N represents the same numerical value as n in the general formula (1).
That is, in the general formula (3), R ¹ represents a residue obtained by removing a hydroxyl group from a linear or branched saturated aliphatic polyhydric alcohol. R ² represents a residue obtained by removing a carboxy group from a linear or branched saturated aliphatic carboxylic acid (or a residue obtained by removing an ester group from a saturated aliphatic carboxylic acid ester). N represents an integer of 2 or more (preferably an integer of 2 or more and 8 or less, more preferably an integer of 3 or more and 6 or less).

  Specific examples of the linear or branched saturated aliphatic polyhydric alcohol of the present embodiment include, for example, ethylene glycol, propylene glycol, 1,2-butylene glycol, 1,3-butylene glycol, and 1,4-butylene. Dihydric alcohols such as glycol, 2,3-butylene glycol, 1,5-pentamethylene glycol, hexylene glycol, octylene glycol, neopentyl glycol; glycerin, trimethylolethane, trimethylolpropane, 1,2,6- Examples include trivalent alcohols such as hexanetriol; tetravalent alcohols such as pentaerythritol; pentavalent alcohols such as xylitol; hexavalent alcohols such as sorbitol, mannitol, and dipentaerythritol; octavalent alcohols such as tripentaerythritol. These may be used alone or in combination of two or more. These polyhydric alcohols preferably have 1 to 20 carbon atoms, more preferably 2 to 15 carbon atoms, and even more preferably 3 to 12 carbon atoms in that they have low-temperature fixability and suppress image loss.

  The saturated aliphatic polyhydric alcohol is preferably divalent to octavalent, more preferably divalent to hexavalent, more preferably trivalent from the viewpoints of low-temperature fixability and suppression of image loss. It is more preferably 6 or less and more preferably 3 or more and 4 or less.

  Among these, the linear or branched saturated aliphatic polyhydric alcohol of the present embodiment is preferably at least one selected from the group consisting of neopentyl glycol, glycerin, and pentaerythritol.

  Among the linear or branched saturated aliphatic monovalent carboxylic acids of the present embodiment, specific examples of the linear saturated aliphatic monovalent carboxylic acid include acetic acid, propanoic acid, butanoic acid, and pentanoic acid. , Hexanoic acid, heptanoic acid, octanoic acid, nonanoic acid, decanoic acid, dodecanoic acid, tetradecanoic acid, pentadecanoic acid, hexadecanoic acid, heptadecanoic acid, octadecanoic acid, eicosanoic acid and the like.

  Among the straight chain or branched chain saturated aliphatic monovalent carboxylic acids of the present embodiment, specific examples of the branched chain saturated aliphatic monovalent carboxylic acid include ethylmethylacetic acid, 2-methylbutanoic acid, 3 -Methylbutanoic acid, 2-ethylbutanoic acid, neopentanoic acid, isoheptanoic acid, 2-methylhexanoic acid, 5-methylhexanoic acid, 2-ethylhexanoic acid, isoheptanoic acid, 2-butyloctanoic acid, isooctanoic acid, 2-methylnonane Examples include acid, isononanoic acid, isodecanoic acid, dimethyloctanoic acid, isotridecanoic acid, 12-methyltridecanoic acid, 2-hexyldecanoic acid, 16-methylheptadecanoic acid, 2-heptylundecanoic acid and the like.

  When the saturated aliphatic monovalent carboxylic acid is in the form of an alkyl ester having 1 to 5 carbon atoms of the monovalent carboxylic acid, for example, methyl ester, ethyl ester, propyl ester of saturated aliphatic monovalent carboxylic acid, Examples thereof include butyl ester and pentyl ester.

  The saturated aliphatic monovalent carboxylic acid (including the lower alkyl ester of carboxylic acid) has a low-temperature fixability and suppresses the loss of image, and the carbon number of the carboxy group (or ester group). 1 to 20 is preferable, 2 to 15 is more preferable, and 3 to 12 is more preferable.

  In addition, even when the specific polyhydric alcohol ester compound is included in the image formed using the liquid developer according to the present embodiment, a phenomenon (bleed) that precipitates on the surface of the image occurs due to environmental conditions or the like. It becomes easy to be suppressed.

  The specific polyhydric alcohol ester compound is considered to enter a binder resin (for example, a polyester resin) and exhibit a plasticizing effect. As the number of ester skeletons in the specific polyhydric alcohol ester compound increases, even if external stimuli due to environmental conditions etc. are given to the image, the specific polyhydric alcohol ester compound has a specific chemical structure. It is considered that precipitation from the resin hardly occurs. When the carboxylic acid portion of the specific polyhydric alcohol ester compound has a branched chain (that is, when the saturated aliphatic monovalent carboxylic acid is a branched saturated aliphatic monovalent carboxylic acid), it has a branched chain that is a polar group. Therefore, it is considered that it is difficult to precipitate from the binder resin.

  From the above, since the specific polyhydric alcohol ester compound of this embodiment has a unique structure, even when an image is formed using the liquid developer according to this embodiment, the occurrence of bleeding is easily suppressed. Presumed to be.

  An example of the specific polyhydric alcohol ester compound of the present embodiment is, for example, a linear or branched saturated aliphatic polyhydric alcohol having 1 to 20 carbon atoms, and 1 to 20 carbon atoms. (However, carbon of a carboxy group is not included.) A reaction product of a linear or branched saturated aliphatic monovalent carboxylic acid (including an alkyl ester having 1 to 5 carbon atoms of a carboxylic acid) is included. In addition, the polyhydric alcohol of the specific polyhydric alcohol ester compound may be divalent or higher (preferably divalent or higher and octavalent or lower, more preferably trivalent or higher and hexavalent or lower).

  Specific examples of the specific polyhydric alcohol ester compound of the present embodiment represented by the general formula (3) are shown below, but are not limited thereto. In addition, the following exemplary compound numbers are described as an exemplary compound (3-number) below. Specifically, for example, “Exemplary Compound (3-15)” is represented below.

  These compounds may be used alone or in combination of two or more. Further, among these compounds, exemplified compound (3-17) (diethylhexanoic acid neopentyl glycol) and exemplified compound (3-14) (dicapric acid) have low-temperature fixability and further suppress image loss. Neopentyl glycol), exemplified compound (3-23) (triethylhexanoin), and exemplified compound (3-34) (tetraethylhexanoic acid pentaerythrityl) are preferred. In particular, at least one of exemplary compound (3-17), exemplary compound (3-23), and exemplary compound (3-34) is more preferable.

Specific polyhydric alcohol ester compound, in terms of suppressing partial deletion, it is preferred that the conductivity is less than 10 ^{-11 S / m,} more preferably not more than 10 -12 ^{S / m.} Although it does not specifically limit as a minimum, It is preferable that it is 10 ^<-15 > S / m or more, and it is preferable that it is 10 ^<-14 > S / m or more. When the electrical conductivity of the specific polyhydric alcohol ester compound is in the above range, a drop in transferability is suppressed, so that image omission is more easily suppressed.

  In this embodiment, the electrical conductivity of the specific polyhydric alcohol ester compound is measured by MPC227 (pH / Conductivity Meter, manufactured by METTLER TOLEDO).

  The content of the specific polyhydric alcohol ester compound is preferably 0.5% by mass or more and 50% by mass or less based on the toner particles from the viewpoint of having low-temperature fixability and suppressing image omission. It is more preferably 5% by mass or more and 20% by mass or less, and further preferably 1% by mass or more and 10% by mass or less. Moreover, generation | occurrence | production of a bleed can also be suppressed by containing in this range. Furthermore, image durability when an image is formed on a thermoplastic resin film is improved, and deformation of the film can be suppressed.

(Other additives)
The carrier liquid has a carrier conductivity within a desired range, and further includes, for example, a dispersant, an emulsifier, a surfactant, a stabilizer, a wetting agent, a thickener, a foaming agent, an antifoaming agent, a coagulant, Various auxiliary materials such as a gelling agent, an anti-settling agent, a charge control agent, an antistatic agent, an anti-aging agent, a softening agent, a filler, a flavoring agent, an anti-tacking agent and a release agent may be contained.

<Liquid developer cartridge>
The liquid developer cartridge according to the present embodiment is a liquid developer cartridge in which the liquid developer of the present embodiment is accommodated. For example, the liquid developer accommodated in the liquid developer cartridge is a supply pipe or the like. To the developing device of the image forming apparatus. The liquid developer cartridge may be attached to and detached from the image forming apparatus in order to replace the liquid developer cartridge when the remaining amount of the liquid developer in the liquid developer cartridge runs out. The form of the liquid developer cartridge of the present embodiment is not particularly limited, but may be a tank form or a bottle form. The form of the liquid developer cartridge may be selected according to the capacity for storing the liquid developer.

<Image Forming Apparatus and Image Forming Method>
The image forming apparatus according to the present embodiment is not particularly limited as long as at least the liquid developer according to the present embodiment is used. For example, the electrostatic latent image holding body and the electrostatic latent image holding A charging device that charges the surface of the body, a latent image forming device that forms an electrostatic latent image on the surface of the electrostatic latent image holding member, the liquid developer according to the present embodiment, and the electrostatic device A developing device that develops an electrostatic latent image formed on the surface of the latent image holding member with the liquid developer to form a toner image, a transfer device that transfers the toner image to a recording medium, and a recording medium on the recording medium. And an image forming apparatus having a fixing device for fixing the toner image to a recording medium. Examples of the fixing device include a fixing device that heats and pressurizes the toner image on the recording medium and fixes the toner image on the recording medium.

  The image forming method according to the present embodiment is not particularly limited as long as at least the liquid developer according to the present embodiment is used. For example, a charging step for charging the surface of the electrostatic latent image holding member. A latent image forming step of forming an electrostatic latent image on the surface of the electrostatic latent image holding member, and a liquid developing method according to the present embodiment using the electrostatic latent image formed on the surface of the electrostatic latent image holding member. An image forming method comprising: a developing step for forming a toner image by developing with an agent; a transfer step for transferring the toner image to a recording medium; and a fixing step for fixing the toner image on the recording medium to the recording medium. Is mentioned. Examples of the fixing step include a fixing step in which the toner image on the recording medium is heated and pressed to be fixed on the recording medium.

In the image forming apparatus (image forming method), it is preferable that the fixing device (fixing step) performs fixing in two stages. Specifically, the first heating device (first heating device) heats the toner image in a non-contact manner to a temperature equal to or higher than the temperature (A) at which the storage elastic modulus of the toner particles in the toner image is 1 × 10 ⁶ Pa. 1 heating step) and a second heating and pressurizing device (second heating heating device) for applying pressure while heating at a temperature equal to or higher than the temperature (A) after heating in the first heating device (after the first heating step). Pressure step).
In the first heating device (first heating step), from the viewpoint of ensuring the fluidity of the toner particles, the toner image on the recording medium is formed by a heating device that performs heating without contact, that is, heating without contact. It is desirable that the heating is performed from the side where the toner is applied, the rear side of the recording medium (the side where the toner image is not formed), or a combination of both.

In the image forming method according to the present embodiment, the recording medium is not particularly limited, and a known recording medium is applied. For example, a thermoplastic resin film may be applied.
Examples of the thermoplastic resin film include polyolefin films such as polyethylene and polypropylene; polyester films such as polyethylene terephthalate and polybutylene terephthalate; polyamide films such as nylon. Other examples include films of polycarbonate, polystyrene, modified polystyrene, polyvinyl chloride, polyvinyl alcohol, polylactic acid, and the like. These films may be any of an unstretched film and a stretched film stretched in a uniaxial direction or a biaxial direction. Further, the thermoplastic resin film may be in the form of a single layer or multiple layers. If necessary, a surface coat layer that assists toner fixing, a plasma treatment, or a corona treatment may be used.

  When a thermoplastic resin film is applied as a recording medium, the thermoplastic resin film is uniaxial or biaxial in terms of deformation of the thermoplastic resin film when an image is formed using the liquid developer of this embodiment. The film is preferably stretched in the direction. Further, when the recording medium is a thermoplastic resin film for use in a soft packaging material, for example, the recording medium is preferably stretched in a uniaxial direction or a biaxial direction from the characteristics required for the flexible packaging material. Moreover, as a thickness of the thermoplastic resin film for using for a flexible packaging material, 5 micrometers or more and 250 micrometers or less are mentioned, for example, Preferably 10 micrometers or more and 100 micrometers or less are mentioned. Furthermore, the thermoplastic resin film may be untreated. From the standpoint of enhancing image fixability, the thermoplastic resin film is subjected to various treatments (for example, resin coating) for improving adhesion, such as corona treatment, ozone treatment, low-temperature plasma treatment, flame treatment, glow discharge treatment, and the like. May be.

Among the thermoplastic resin films listed above, the thermoplastic resin film on which an image is formed is more preferably at least one of a polyolefin film, a polyester film, and a polyamide film, a polyethylene terephthalate film, a polypropylene, And at least one selected from the group consisting of nylon films. In the case of a multilayer film, the surface on which an image is formed is more preferably at least one thermoplastic resin film selected from the group consisting of a polyolefin film, a polyester film, and a polyamide film, and a polyethylene terephthalate film It is further desirable that it is at least one selected from the group consisting of polypropylene, and nylon film. At least one of polyethylene terephthalate film and polypropylene is particularly desirable.
The polyethylene terephthalate film, polypropylene, and nylon film are more preferably stretched uniaxially or biaxially.

  Hereinafter, the configuration of the image forming method and the image forming apparatus according to the present embodiment will be described in detail with reference to the drawings.

FIG. 1 is a schematic configuration diagram illustrating an example of an image forming apparatus according to the present embodiment.
The image forming apparatus 100 includes a photosensitive member (electrostatic latent image holding member) 10, a charging device 20, an exposure device (latent image forming device) 12, a developing device 14, an intermediate transfer member 16, a cleaner 18, and a transfer roll (transfer device). 28, a non-contact heating device (first heating device) 32, and heating and pressing rolls (second heating and pressing device) 34A and 34B.
The photosensitive member 10 has a cylindrical shape, and a charging device 20, an exposure device 12, a developing device 14, an intermediate transfer member 16, and a cleaner 18 are sequentially provided on the outer periphery of the photosensitive member 10. Further, a transfer roll 28 is provided at a position where the toner image 26 transferred to the intermediate transfer body 16 is transferred to the recording medium 30. Further, a non-contact heating device (first heating device) 32 is provided on the downstream side of the transfer roll 28 in the traveling direction of the recording medium 30, and heating is performed on the downstream side of the non-contact heating device 32 in the traveling direction of the recording medium 30. Pressure rolls (second heating and pressure devices) 34A and 34B are provided in pairs.

  The operation of the image forming apparatus 100 will be briefly described below.

The charging device 20 charges the surface of the photoconductor 10 to a predetermined potential, and based on the image signal, the exposure device 12 exposes the charged surface with, for example, a laser beam to form an electrostatic latent image.
The developing device 14 includes a developing roll 14a and a developer storage container 14b. The developing roll 14a is provided so that a part thereof is immersed in the liquid developer 24 stored in the developer storage container 14b. In the liquid developer 24, the toner particles are dispersed. However, for example, the liquid developer 24 may be further stirred by a stirring member provided in the developer storage container 14b.

  The liquid developer 24 supplied to the developing roll 14a is conveyed to the photoconductor 10 in a state limited to the supply amount determined by the regulating member, and the position where the developing roll 14a and the photoconductor 10 face (or contact) each other. Is supplied to the electrostatic latent image. As a result, the electrostatic latent image is visualized and becomes a toner image 26.

  The developed toner image 26 is conveyed to the photoreceptor 10 rotating in the direction of arrow B in the figure and transferred to the recording medium 30. In this embodiment, before transferring to the recording medium 30, the intermediate transfer is temporarily performed. The toner image is transferred to the body 16. At this time, a peripheral speed difference may be provided between the photosensitive member 10 and the intermediate transfer member 16.

  Next, the toner image conveyed in the direction of arrow C by the intermediate transfer member 16 is transferred to the recording medium 30 at a position where the toner image is in contact with the transfer roll 28.

A non-contact heating device (first heating device) 32 is provided downstream of the transfer roll 28 in the traveling direction of the recording medium 30. The non-contact heating device 32 is a plate-like heating device, and a heater is provided inside a plate-like body whose surface is made of metal. At the position of the non-contact heating device 32, the toner image is heated to a temperature equal to or higher than the temperature (A) at which the storage elastic modulus of the toner particles becomes 1 × 10 ⁶ Pa.

As the heater used in the non-contact heating device 32, for example, when the toner image is heated in a non-contact manner from the toner image side to be heated, a halogen heater, a hot air dryer or the like is used as the toner image to be heated. When heating from the back surface (that is, the recording medium side), a heating plate, a heating roll, or the like that contacts the back surface is used.
The heating temperature in the non-contact heating device 32 is desirably 70 ° C. or higher. However, when a thermoplastic resin film is used as the recording medium, it is preferably 70 ° C. or higher and lower than 110 ° C., more preferably 80 ° C. or higher and 100 ° C. or lower, and 80 ° C. or higher and 90 ° C. or lower. Is more desirable. The heating time is determined by the length of the non-contact heating device 32 in the traveling direction of the recording medium 30 and the process speed.

Heating and pressing rolls (second heating and pressing devices) 34A and 34B are provided downstream of the non-contact heating device (first heating device) 32 in the traveling direction of the recording medium 30. The toner image heated by the non-contact heating device 32 is further pressed while being heated by the heating and pressure rolls 34A and 34B at a temperature equal to or higher than the temperature (A), so that the recording medium 30 is heated. It is fixed.
The heating and pressing rolls 34A and 34B are arranged to face each other so as to form a nip with the recording medium 30 interposed therebetween. The heat and pressure rolls 34A and 34B form an elastic rubber layer and a release layer for releasing the toner on a metal roll, and a recording medium 30 is formed by a pressure mechanism (not shown) so as to obtain a predetermined pressure and nip width. Is sandwiched. In addition, at least one of the heat and pressure rolls 34A and 34B includes a heater, but the heater may include both the heat and pressure rolls 34A and 34B.

The heating temperature of the heating and pressing rolls (second heating and pressing apparatus) 34A and 34B is preferably a temperature equal to or higher than the temperature (A). When a thermoplastic resin film is used, it is preferably 70 ° C. or higher and lower than 110 ° C., more preferably 80 ° C. or higher and 100 ° C. or lower, and further preferably 80 ° C. or higher and 90 ° C. or lower. The applied pressure is desirably 1.5 kg / cm ² or more and 5 kg / cm ² or less, and more desirably 2 kg / cm ² or more and 3.5 kg / cm ² or less.

  The toner image is fixed on the recording medium 30 at the positions of the heat and pressure rolls 34A and 34B, and a fixed image 29 is formed. Thereafter, the recording medium 30 is conveyed to a discharge unit (not shown).

  On the other hand, in the photoconductor 10 that has transferred the toner image 26 to the intermediate transfer body 16, the toner particles that are not transferred and remain on the photoconductor 10 are conveyed to a contact position with the cleaner 18 and collected by the cleaner 18. If the transfer efficiency is close to 100% and the generation of residual toner particles is reduced, the cleaner 18 need not be provided.

The image forming apparatus 100 may further include a neutralization device (not shown) that neutralizes the surface of the photoconductor 10 after the transfer and before the next charging.
The charging device 20, the exposure device 12, the developing device 14, the intermediate transfer member 16, the transfer roll 28, the cleaner 18, the non-contact heating device (first heating device) 32, and the heating and pressing roll (provided in the image forming apparatus 100 The second heating / pressurizing devices 34A and 34B are all operated in synchronism with the rotational speed of the photoconductor 10.

  Next, another aspect of the image forming apparatus according to this embodiment will be described in detail with reference to the drawings.

FIG. 2 is a schematic configuration diagram illustrating an example of another aspect of the image forming apparatus according to the present embodiment, and is a diagram illustrating a tandem image forming apparatus.
The image forming apparatus illustrated in FIG. 2 includes a cyan developing unit 101-C, a magenta developing unit 101-M, a yellow developing unit 101-Y, and a black developing unit 101-K. Each developing unit includes a developer tank 102, a developer supply roll 103, a supply amount regulating means 104, a developing roll (developing device) 105, a developing roll cleaner 106, a photosensitive member (electrostatic latent image holding member) 107, and a charging device 108. , An exposure device (latent image forming device) 109, a primary transfer device 110, and a photoreceptor cleaner 111. Further, an intermediate transfer body 125 is provided so as to be in contact with each of the photosensitive members 107 of the four developing units, and further, secondary transfer devices 124 and 126 that transfer the toner image transferred to the intermediate transfer body 125 to the recording medium 127 are provided. Provided. A fixing unit (fixing device) 131 is provided on the downstream side of the secondary transfer devices 124 and 126 in the traveling direction of the recording medium 127, and a discharge roller 135 is provided on the downstream side of the fixing unit 131.
The fixing unit 131 includes a non-contact heating device (first heating device) 136 and 138, a heat roll 132 and a pressure roll 133 (second heating and pressing device) in order from the upstream side in the direction of travel of the recording medium 127. It is done.

  The liquid developer 112 is maintained in a predetermined amount in the developer tank 102 by a developer circulation means (not shown), and is conveyed from the developer tank 102 to the developing roll 105 by the developer supply roll 103. The developer supply roll 103 includes a system in which the surface is charged and the developer is attached by an electrostatic force, and a system in which a groove or a recess is provided in the roll to convey the liquid so as to supply liquid. The transport amount is restricted to a predetermined value. The photosensitive member 107 is charged by a charging device 108 so that the surface has a predetermined charging bias amount, and an electrostatic latent image is formed on the surface by a light beam from the exposure device 109 in accordance with an image signal sent from a host computer (not shown). It is formed. The liquid developer on the developing roll 105 is transferred to the photoreceptor 107 in accordance with the electrostatic latent image to form a toner image. Unnecessary developer is removed from the developer tank 102 by the developing roll cleaner 106 and a developer circulating means (not shown). Returned to

  The toner image formed on the photosensitive member 107 is transferred to the intermediate transfer member 125 by the primary transfer device 110. The intermediate transfer body 125 is supported by a drive roll 121, support rolls 122 and 123, and a secondary transfer device 124. The drive roll 121 drives the intermediate transfer body 125 in the direction of the arrow by a drive motor and a power transmission mechanism (not shown). Further, a tension determined by a spring mechanism (not shown) is applied to the intermediate transfer body 125. The primary transfer device 110 sequentially transfers cyan, magenta, yellow, and black toner images to the intermediate transfer member 125 by electrostatic force and pressure. The primary transfer device 110 for each color may make a difference in the set potential. The liquid developer remaining on the photoconductor 107 is removed by the photoconductor cleaner 111.

The toner image transferred to the intermediate transfer member 125 is transferred to the recording medium 127 by the secondary transfer devices 124 and 126 and further fixed by the fixing unit 131.
The fixing unit 131 includes a first heating device and a second heating and pressing device in order from the upstream side in the traveling direction of the recording medium 127, and includes non-contact heating devices 136 and 138 as the first heating device. The non-contact heating devices 136 and 138 are plate-like heating devices, and a heater is provided inside a plate-like body whose surface is made of metal. At the positions of the non-contact heating devices 136 and 138, the toner image is heated to a temperature equal to or higher than the temperature (A) at which the storage elastic modulus of the toner particles becomes 1 × 10 ⁶ Pa.

  The heating temperature in the non-contact heating devices 136 and 138 is desirably 70 ° C. or higher. However, when a thermoplastic resin film is used as the recording medium, it is preferably 70 ° C. or higher and lower than 110 ° C., more preferably 80 ° C. or higher and 100 ° C. or lower, and 80 ° C. or higher and 90 ° C. or lower. Is more desirable. The heating time is determined by the length of the recording medium 127 in the traveling direction of the non-contact heating devices 136 and 138 and the process speed.

Further, the fixing unit 131 includes a roll pair of a heat roll 132 and a pressure roll 133 and a heater 134 provided inside each roll as a second heating and pressing apparatus. The toner images heated by the non-contact heating devices 136 and 138 are further pressed while being heated at a temperature equal to or higher than the temperature (A) by the roll pair of the heat roll 132 and the pressure roll 133. Then, it is fixed on the recording medium 127.
The heat roll 132 and the pressure roll 133 are arranged to face each other so as to form a nip across the recording medium 127. Each of the heat roll 132 and the pressure roll 133 is formed with an elastic rubber layer and a release layer for releasing the toner particles on the metal roll, and a pressure mechanism (not shown) so as to obtain a predetermined pressure and nip width. Thus, the recording medium 127 is sandwiched. Moreover, although the heater is provided in both the heat roll 132 and the pressure roll 133, this heater may be provided only in one of the heat roll 132 and the pressure roll 133.

The heating temperature of the heat roll 132 and the pressure roll 133 is preferably equal to or higher than the temperature (A). When a thermoplastic resin film is used, it is preferably 70 ° C. or higher and lower than 110 ° C., more preferably 80 ° C. or higher and 100 ° C. or lower, and further preferably 80 ° C. or higher and 90 ° C. or lower. The applied pressure is desirably 1.5 kg / cm ² or more and 5 kg / cm ² or less, and more desirably 2 kg / cm ² or more and 3.5 kg / cm ² or less.

  Further, a discharge roll 135 is provided on the downstream side of the fixing unit 131, and the recording medium 127 on which the toner image is fixed is conveyed by the discharge roll 135 to a discharge unit (not shown).

  As the first heating device, FIG. 1 shows a plate-like heating device that is heated from the back side (opposite side of the toner image) of the recording medium and has a heater inside, and FIG. 2 has a heater inside. The method of heating in a non-contact manner from both the front and back sides of the recording medium with a plate-shaped heating device has been described, but the method of the first heating device is not limited to this, and the front side (toner image side) of the recording medium is not contacted Any material can be used as long as it can be heated. For example, heating may be performed only from the front side (toner image side) of the recording medium by a plate-shaped heating device provided with a heater inside. Moreover, you may apply the air blower which blows a hot air, the irradiation apparatus which irradiates infrared light, etc.

  Further, as the second heating and pressing apparatus, FIG. 1 shows a pair of heating and pressing rolls 34A and 34B, and FIG. 2 shows a pair of heating roll 132 and a pressure roll 133. However, the present invention is not limited to this. Absent. For example, an apparatus that combines a heating and pressing roll and a pressing belt, an apparatus that combines a pressing roll and a heating and pressing belt, and the like may be used.

  In the image forming apparatus shown in FIGS. 1 and 2, the liquid developer is supplied from the liquid developer cartridge (not shown) attached to the image forming apparatus to the developer storage container 14b or the developer tank 102. It is good. Further, the liquid developer cartridge may be configured to be attached to and detached from the image forming apparatus so that the liquid developer cartridge can be replaced when the remaining amount of the liquid developer is exhausted.

  Hereinafter, although an embodiment explains this embodiment in detail, this embodiment is not limited to these examples at all. In the following description, “part” and “%” are all based on mass unless otherwise specified.

<Manufacture of toner particles>
-Preparation of Amorphous Polyester Resin (1) / Amorphous Resin Particle Dispersion (1a)-
・ Polyoxyethylene (2,0) -2,2-bis (4-hydroxyphenyl) propane
35 mole parts polyoxypropylene (2,2) -2,2-bis (4-hydroxyphenyl) propane
65 mol parts, terephthalic acid 80 mol parts, n-dodecenyl succinic acid 15 mol parts, trimellitic acid 10 mol parts In a two-necked flask heated and dried, the above components and these acid components (terephthalic acid, n-dodecenyl succinic acid, 0.05 mol part of dibutyltin oxide with respect to the total number of moles of trimellitic acid), and after introducing nitrogen gas into the container and keeping it in an inert atmosphere and raising the temperature, 150 ° C. or higher and 230 ° C. or lower Then, a copolycondensation reaction was carried out for 12 hours, and then the pressure was gradually reduced from 210 ° C. to 250 ° C. to synthesize an amorphous polyester resin (1).

The amorphous polyester resin (1) obtained by molecular weight measurement (polystyrene conversion) by GPC (gel permeation chromatography) had a weight average molecular weight (Mw) of 15000 and a number average molecular weight (Mn) of 6800.
Further, when the amorphous polyester resin (1) was measured by using a differential scanning calorimeter (DSC), a clear peak was not shown, and a stepwise change in the endothermic amount was observed. The glass transition temperature at the midpoint of the stepwise endothermic change was 62 ° C.

3000 parts of the obtained amorphous polyester resin (1), 10000 parts of ion-exchanged water, and 90 parts of surfactant sodium dodecylbenzenesulfonate are added to an emulsification tank of a high-temperature and high-pressure emulsifier (Cabitron CD1010, slit: 0.4 mm). After being charged, the mixture is heated and melted to 130 ° C., dispersed at 110 ° C. at a flow rate of 3 L / m for 30 minutes at 10,000 rpm, and passed through a cooling tank to pass through an amorphous resin particle dispersion (high temperature high pressure emulsifier (Cabitron CD1010 slit). 0.4 mm)) was recovered to obtain an amorphous resin particle dispersion (1a).
The volume average particle diameter D50v of the resin particles contained in the obtained amorphous resin particle dispersion (1a) was 0.3 μm, and the standard deviation was 1.2.

-Preparation of crystalline polyester resin (2) and crystalline resin particle dispersion (2a)-
・ 1,4-butanediol (manufactured by Wako Pure Chemical Industries, Ltd.) 293 parts ・ dodecanedicarboxylic acid (manufactured by Wako Pure Chemical Industries, Ltd.) 750 parts ・ catalyst (dibutyltin oxide) 0.3 parts After the above components were added, the air in the container was brought into an inert atmosphere with nitrogen gas by a depressurization operation, and stirred at 180 ° C. for 2 hours by mechanical stirring. Then, it heated up gradually to 230 degreeC under pressure reduction, stirred for 5 hours, air-cooled when it became a viscous state, the reaction was stopped, and the crystalline polyester resin (2) was synthesize | combined.

The weight average molecular weight (Mw) of the crystalline polyester resin (2) obtained by molecular weight measurement (polystyrene conversion) by GPC (gel permeation chromatography) was 18000.
Further, when the melting temperature (Tm) of the crystalline polyester resin (2) was measured using a differential scanning calorimeter (DSC) by the above-described measuring method, it had a clear peak, and the peak top temperature was 70 ° C. Met.
Furthermore, a crystalline resin particle dispersion (2a) was produced under the same conditions as in the amorphous resin particle dispersion (1a) except that the crystalline polyester resin (2) was used. The volume average particle diameter D50v of the particles contained in the obtained dispersion was 0.25 μm, and the standard deviation was 1.3.

-Preparation of colorant particle dispersion (1)-
・ Phthalocyanine pigment (Daiichi Seika Co., Ltd., PVFASTBLUE) 25 parts ・ Anionic surfactant (Daiichi Kogyo Seiyaku Co., Ltd., Neogen RK) 2 parts ・ Ion-exchanged water 125 parts After mixing and dissolving the above components, homogenizer (IKA) Dispersion was carried out using Ultra Tarrax) to obtain a colorant particle dispersion (1).

-Preparation of release agent particle dispersion (1)-
・ Pentaerythritol behenic acid tetraester wax 100 parts ・ Anionic surfactant (manufactured by NOF Corporation, Newlex R) 2 parts ・ Ion exchange water 300 parts After mixing and dissolving the above components, homogenizer (manufactured by IKA, Ultrata) (Lux) and then dispersed with a pressure discharge type homogenizer to obtain a release agent particle dispersion (1).

-Production of toner particles (1)-
Amorphous resin particle dispersion (1a) 145 parts Crystalline resin particle dispersion (2a) 30 parts Colorant particle dispersion (1) 42 parts Release agent particle dispersion (1) 36 parts Aluminum (manufactured by Wako Pure Chemical Industries, Ltd.) 0.5 parts, ion-exchanged water 300 parts The above components are contained in a round stainless steel flask and adjusted to pH 2.7, and a homogenizer (manufactured by IKA, Ultra Turrax T50) Then, the mixture was heated to 45 ° C. with stirring in an oil bath for heating. After maintaining at 48 ° C. for 120 minutes, observation with an optical microscope confirmed that aggregated particles having an average particle size of 5.6 μm were formed.
Furthermore, after maintaining heating and stirring at 48 ° C. for 30 minutes, observation with an optical microscope confirmed that aggregated particles having an average particle diameter of 6.5 μm were formed. The pH of this aggregated particle dispersion was 3.2. Subsequently, a 1N aqueous sodium hydroxide solution was gently added to adjust the pH to 8.0, and then the mixture was heated to 90 ° C. while maintaining stirring and maintained for 2 hours. Thereafter, the reaction product was filtered, washed with ion exchange water, and then dried using a vacuum dryer to obtain toner particles (1). The obtained toner particles (1) had a volume average particle diameter D50v of 5.2 μm.

<Example 1>
-Preparation of liquid developer (A1)-
40 parts of the toner particles (1) obtained above, 50 parts of dimethyl silicone oil (manufactured by Shin-Etsu Chemical Co., Ltd., KF-96-20cs), and the polyhydric alcohol ester compound of the plasticizer are exemplified compounds (3-17). 5 parts (12.5% by mass with respect to toner particles) were weighed (diethylhexanoic acid neopentyl glycol: Nisshin Oilio Group, Cosmol 525). Next, a glass container was previously mixed with dimethyl silicone oil and neopentyl glycol diethylhexanoate to prepare a mixture, and toner particles were charged into this mixture. The container is sealed with a lid and premixed with a spatula, and then blended at a blender (manufactured by IKA, Ultra Turrax Homogenizer Digital T-25) at a rotation speed of 10,000 rpm for 20 seconds to obtain a liquid developer (A1). It was.

<Examples 2 to 7, Comparative Examples 1 to 3>
-Preparation of liquid developers (A2-A7, C1-C3)-
According to Table 1, a developer was prepared in the same manner as in Example 1 except that the type and amount of the polyhydric alcohol ester compound were changed, and liquid developers (A2 to A7, C1 to C3) were obtained. In C1, a plasticizer was not added, and in C2 and C3, it was changed to an ester compound of a monovalent alcohol and a polyvalent carboxylic acid. As the C3 diisononyl phthalate, DINP (trade name, manufactured by Daihachi Chemical Industry Co., Ltd.) was used.

<Evaluation sample preparation>
First, a biaxially stretched polypropylene film (FOR (manufactured by count 15) manufactured by Futamura Chemical Co., Ltd.) and a polyethylene terephthalate film (Espet film T4102 manufactured by Toyobo Co., Ltd.) were prepared as recording media. On the medium, the toner particle mass (TMA) in each liquid developer is 3.5 g / m ² , the carrier liquid mass (CMA) is 4.8 g / m ² , and the coating area is 8 cm × 5 cm. Adjustment (removed the excess with a waste cloth) was performed to form a coating film with each liquid developer.
Thereafter, the fixing condition is preheating without contact at the first stage at 100 ° C., second stage at 95 ° C., 2.7 kg / cm ² , and heating and pressurizing with a pair of fixing rolls at a speed of 60 m / min, A fixed image was formed on each recording medium and used as an evaluation sample. For the evaluation sample of the biaxially stretched polypropylene film, a fixing image was formed by setting the temperature condition of the second stage fixing roll to 85 ° C., 95 ° C., or 105 ° C. and used as an evaluation sample.

<Fixability evaluation>
Fixability was evaluated by pencil hardness evaluation.
Pencil hardness tester: (All Good)
Pencil: Pencil hardness test pencil (sold by Japan Paint Inspection Association)

-Evaluation criteria for fixability-
A (◯): 4B or more B (△): 5B
C (x): less than 5B

<Evaluation of film deformation>
The evaluation sample of the polyethylene terephthalate film obtained above and the evaluation sample fixed at 105 ° C. as the fixing temperature for the second stage of the biaxially stretched polypropylene film were left in a constant temperature tester at 40 ° C. for 24 hours. Then, it returned to room temperature and implemented the state which the film deform | transformed by sensory evaluation.

-Evaluation criteria for film deformation-
A (◯): No film deformation was observed, and the state of the film alone was not inferior.
B (Δ): Some film shrinkage is observed, but no warpage of the entire film is observed.
C (x): Film shrinkage is clearly observed and the film is warped.

<Evaluation of image durability>
First, an evaluation sample of the polyethylene terephthalate film obtained above and an evaluation sample fixed at 105 ° C. are prepared as the second stage fixing temperature of the biaxially stretched polypropylene film. A sample for evaluation of image durability was formed by superimposing the surfaces of each evaluation sample on which the fixing film was formed and the surface of each evaluation sample on which the fixing film was formed and the surface on which the fixing film was not formed. This sample was allowed to stand for one day with a constant temperature and high humidity tester at a temperature of 60 ° C. and a humidity of 50% under a load of 80 g / cm ^2. Whether or not (image loss or image transfer) occurred was observed and evaluated according to the following evaluation criteria.

-Evaluation criteria for image durability-
A (◯): Very slight image defect (to the extent that one or more defects are confirmed under magnified observation).
B (Δ): Image loss in an area of 1/3 or less.
C (x): Image defect exceeding 1/3.

<Evaluation of bleed>
The polyethylene terephthalate film evaluation sample obtained above was left in a constant temperature and high humidity tester at 60 ° C. and 50% humidity for 5 days, and then left at room temperature for 3 hours. Next, a medicine-wrapping paper was placed on the surface of this image, a metal disk having a diameter of 1 cm was applied with a weight of 30 g / cm ² and left for one hour, and the wettability of the medicine-wrapping paper was evaluated by visual sensory evaluation. The difference in the diameter of the oozing area was evaluated.

-Bleed evaluation criteria-
A (◯): 0 mm or more and less than 3 mm B (Δ): 3 mm or more and less than 5 mm C (x): 5 mm or more

<Evaluation of missing images>
Two ITO electrodes (sheet resistance 100Ω / □) cut into 1 cm × 5 cm strips are opposed to each other with a gap of 0.5 mm, and immersed in the liquid developers of Examples and Comparative Examples, respectively, and a DC voltage of 100 V is applied for 5 seconds. Apply and develop toner on the electrode to produce a solid image. This solid image was visually observed and sensory evaluation was performed.

-Evaluation criteria for missing images-
A (◯): The image is smooth and, on average, it is a uniform solid image.
B (Δ): Some shading is observed, but a pattern in which an image flows is not seen.
C (x): An island pattern with a flowing image is clearly seen.

Tables 1 and 2 list each example and each comparative example and their evaluation results.
In Table 1, in the specific paraffin oil column, “to toner particles” represents the content (mass%) relative to the toner particles, and “whole carrier liquid” represents the content (mass%) relative to the entire carrier liquid. .

  From the above results, it can be seen that in this example, the evaluations of “fixability” and “image loss” are particularly excellent as compared with the comparative example. Thus, it can be seen that the present example has a low-temperature fixability and the image omission is suppressed as compared with the comparative example.

10 Photoconductor (electrostatic latent image holder)
12 Exposure device (latent image forming device)
14 Developing device 16 Intermediate transfer body 18 Cleaner 20 Charging device 24 Liquid developer 26 Toner image 28 Transfer roll 29 Fixed image 30 Recording medium 32 Non-contact heating device (first heating device)
34A, 34B Heating and pressing roll (second heating and pressing device)
100 Image forming apparatus 101-C Cyan developing unit 101-M Magenta developing unit 101-Y Yellow developing unit 101-K Black developing unit 102 Developer tank 103 Developer supplying roll 104 Supply amount regulating means 105 Developing roll 106 Developing roll cleaner 107 Photoconductor (electrostatic latent image holder)
108 Charging Device 109 Exposure Device (Latent Image Forming Device)
110 Primary transfer device 111 Photoconductor cleaner 112 Liquid developer 121 Drive roll 122 Support rolls 124 and 126 Secondary transfer device 125 Intermediate transfer body 127 Recording medium 131 Fixing unit (fixing device)
132 Heat roll (second heating and pressurizing device)
133 Pressure roll (second heating and pressurizing device)
134 heater 135 discharge roll 136,138 non-contact heating device (first heating device)

Claims (8)

Toner particles,
Carrier liquid,
A polyhydric alcohol ester compound comprising a reaction product of a linear or branched saturated aliphatic polyhydric alcohol and a linear or branched saturated aliphatic monovalent carboxylic acid, contained in the carrier liquid;
Have
A liquid developer having a content of the polyhydric alcohol ester compound of 0.5% by mass or more and 50% by mass or less based on toner particles . The liquid developer according to claim 1, wherein the polyhydric alcohol ester compound has a conductivity of 10 ⁻¹¹ S / m or less.   The liquid developer according to claim 1, wherein the saturated aliphatic polyhydric alcohol has a valence of 3 or more and 6 or less.   The liquid developer according to any one of claims 1 to 3, wherein the carrier liquid contains 50% by mass or more and 100% by mass or less of silicone oil as a content with respect to the total amount of the carrier liquid.   A liquid developer cartridge that stores the liquid developer according to claim 1 and is detachable from an image forming apparatus. An electrostatic latent image carrier;
A charging device for charging the surface of the electrostatic latent image holding member;
A latent image forming apparatus that forms an electrostatic latent image on the surface of the electrostatic latent image holding member;
The liquid developer according to claim 1 is stored, and the electrostatic latent image formed on the surface of the electrostatic latent image holding member is developed with the liquid developer to form a toner image. A developing device for forming
A transfer device for transferring the toner image to a recording medium;
A fixing device for fixing the toner image on the recording medium to the recording medium;
An image forming apparatus. A charging step for charging the surface of the electrostatic latent image holding member;
A latent image forming step of forming an electrostatic latent image on the surface of the electrostatic latent image holder;
A developing step of developing a toner image by developing the electrostatic latent image formed on the surface of the electrostatic latent image holding member with the liquid developer according to any one of claims 1 to 4,
A transfer step of transferring the toner image to a recording medium;
A fixing step of fixing the toner image on the recording medium to the recording medium;
An image forming method comprising:   The image forming method according to claim 7, wherein the recording medium is at least one selected from the group consisting of a polyethylene terephthalate film, a polypropylene film, and a nylon film.