JP2009057399A - Colored resin fine particles, colored resin fine particle dispersion, method for producing colored resin fine particles and method for producing colored resin fine particle dispersion - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide colored resin fine particles excellent in charging characteristics of positive charge and a method for producing such colored resin fine particles by using an acrylic resin, and to provide a colored resin fine particle dispersion excellent in dispersion stability as well as in charging characteristics of positive charge and a method for producing such a colored resin fine particle dispersion. <P>SOLUTION: The colored resin fine particles comprise a colorant, an acrylic resin and an amine compound having an amine value of 1-100 mgKOH/g and has a content of the amine compound of 0.9-9.1 wt.%. The amine compound is preferably an amine compound whose main chain has a polyester skeleton. The colored resin fine particles preferably have a particle size distribution Dv/Dn of 1.00-1.12. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a colored resin fine particle, a colored resin fine particle dispersion, a method for producing a colored resin fine particle, and a method for producing a colored resin fine particle dispersion.

  As fine particles containing a resin material and a colorant, that is, colored fine resin particles, for example, toners used in image forming apparatuses such as printers, copiers, and facsimiles employing an electrophotographic method, or by applying an electric field, There are electrophoretic particles for electrophoretic display devices in which electrophoretic liquid is electrophoresed by Coulomb force to display desired information (images).

  As a resin material used for such colored resin fine particles, an acrylic resin material (for example, a styrene-acrylic copolymer) is widely used. Such an acrylic resin has excellent weather resistance and high transparency, and when used as a constituent material for the toner and electrophoretic particles described above, the color developability of the resulting image can be increased. . Further, when used as such electrophoretic particles or toner (toner particles) for liquid developer (liquid toner) dispersed in a carrier liquid (insulating liquid) having high electrical insulation, It has a feature that the dispersion stability of the colored resin fine particles in the insulating liquid can be made excellent.

By the way, examples of the liquid developer described above include a negatively chargeable liquid developer and a positively chargeable liquid developer. When a negatively chargeable liquid developer is used, an image is formed. In addition, ozone is generated inside the image forming apparatus, causing problems such as environmental problems and adverse effects on peripheral components in the image forming apparatus.
Therefore, in recent years, since it is possible to perform image formation by reducing the amount of discharge products such as ozone, development of a method for forming an image using a positively chargeable liquid developer has been promoted (for example, Patent Document 1).

  However, the acrylic resin is usually a resin material having high negative chargeability, and it has been difficult to apply it to positively chargeable toner particles. When such an acrylic resin is used for positively charged toner particles, the toner particles cannot be sufficiently charged, the development efficiency is lowered, and a toner image having a sufficiently uniform image density is obtained. It could not be formed stably. Further, it is conceivable to add a charge control agent to toner particles using an acrylic resin as a binder resin for positive charging, but it is difficult to obtain a sufficient charge amount.

JP 2002-214849 A

  An object of the present invention is to provide a colored resin fine particle excellent in positive charging characteristics using an acrylic resin, and a method for producing such a colored resin fine particle, and also excellent in positive charging characteristics. Another object is to provide a colored resin fine particle dispersion excellent in dispersion stability and a method for producing such a colored resin fine particle dispersion.

Such an object is achieved by the present invention described below.
The colored resin fine particles of the present invention include a colorant,
Acrylic resin,
An amine compound having an amine value of 1 to 100 mgKOH / g,
The content of the amine compound is 0.9 to 9.1 wt%.

In the colored resin fine particles of the present invention, the amine compound preferably has a main chain having a polyester skeleton.
In the colored resin fine particles of the present invention, the particle size distribution Dv / Dn is preferably 1.00 to 1.12.
In the colored resin fine particles of the present invention, the amine compound is an aliphatic amine having a functional group represented by —NHR and / or —NR′R ″ (where R, R ′, and R ″ are alkyl groups). It is preferable that

In the colored resin fine particles of the present invention, the colored resin fine particles are dispersed in an aqueous dispersion medium in which the dispersoid containing the colorant, the acrylic resin, the amine compound, and the organic solvent is dispersed in the aqueous dispersion medium. It is preferable to be produced by combining the dispersoids.
The colored resin fine particles of the present invention are preferably toner particles.

The colored resin fine particle dispersion of the present invention has colored resin fine particles and an insulating liquid,
The colored resin fine particles include a colorant, an acrylic resin, and a compound having an amine value of 1 to 100 mgKOH / g.
The content of the amine compound is 0.9 to 9.1 wt%.
In the colored resin fine particle dispersion of the present invention, the colored resin fine particle dispersion is preferably a liquid developer (liquid toner).

The method for producing colored resin fine particles of the present invention is a dispersion in which a dispersoid containing a colorant, an acrylic resin, an amine compound having an amine value of 1 to 100 mgKOH / g, and an organic solvent is dispersed in an aqueous dispersion medium. A dispersion preparation step of preparing
Coalescing a plurality of the dispersoids to obtain coalesced particles; and
Removing the organic solvent contained in the coalesced particles to obtain a colored resin fine particle,
The colored resin fine particles obtained in the solvent removal step contain 0.9 to 9.1 wt% of the amine compound.
In the method for producing colored resin fine particles of the present invention, the dispersion is obtained by adding an aqueous liquid to a solution containing the colorant, the acrylic resin, the amine compound, and the organic solvent. In the emulsified liquid of the mold, it is preferable that a dispersoid containing the colorant, the acrylic resin, the amine compound, and the organic solvent is dispersed in an aqueous dispersion medium.

In the method for producing a colored resin fine particle dispersion of the present invention, a dispersoid containing a colorant, an acrylic resin, an amine compound having an amine value of 1 to 100 mgKOH / g, and an organic solvent is dispersed in an aqueous dispersion medium. A dispersion preparation step for preparing a dispersion;
Coalescing a plurality of the dispersoids to obtain coalesced particles; and
Removing the organic solvent contained in the coalesced particles to obtain a colored resin fine particle, and a dispersion step of dispersing the colored resin fine particle in an insulating liquid,
The colored resin fine particles obtained in the solvent removal step contain 0.9 to 9.1 wt% of the amine compound.

  By satisfying the above configuration, it is possible to provide a colored resin fine particle excellent in positive charging characteristics using an acrylic resin, and a method for producing such a colored resin fine particle. It is possible to provide a colored resin fine particle dispersion having excellent characteristics and excellent dispersion stability, and a method for producing such a colored resin fine particle dispersion.

Hereinafter, preferred embodiments of the present invention will be described in detail.
The use of the colored resin fine particles of the present invention is not particularly limited. For example, toner used in an image forming apparatus such as a printer adopting an electrophotographic method, or electrophoretic particles for an electrophoretic display device such as electronic paper. It can use suitably for. In particular, when such colored resin fine particles are used as toner particles for a liquid developer (liquid toner) dispersed in a carrier liquid (insulating liquid) having high electrical insulation, the following excellent results are obtained. An effect can be obtained. That is, such a liquid developer has excellent dispersion stability, positive charging characteristics (positive charging characteristics), and excellent development efficiency. As a result, the obtained toner image has high color developability and a uniform image density. In the following description, the colored resin fine particles of the present invention will be described in detail by taking toner particles for a liquid developer as representative examples.

≪Liquid developer (colored resin fine particle dispersion) ≫
First, the liquid developer will be described.
The liquid developer described in this embodiment is a colored resin fine particle dispersion in which toner particles (colored resin fine particles) mainly composed of a resin material are dispersed in an insulating liquid.
Such toner particles contain an acrylic resin as a resin material and a predetermined amount of an amine compound having an amine value of 1 to 100 mgKOH / g. As a result, the liquid developer has excellent dispersion stability, positive chargeability, and excellent development efficiency, and the resulting toner image has high color developability and a uniform image density. Hereinafter, each component constituting the liquid developer will be described in detail.

<Toner particles (colored resin fine particles)>
First, toner particles (colored resin fine particles) will be described.
[Component material of toner particles (toner material)]
The toner particles (toner) constituting the liquid developer include at least an acrylic resin as a resin material (binder resin) and an amine compound having an amine value of 1 to 100 mgKOH / g.

  In the present invention, the resin material (binder resin) contained in the toner particles is mainly composed of an acrylic resin. Acrylic resin has high transparency, and when used as a binder resin, the resulting image can have excellent color developability. In addition, acrylic resin is excellent in weather resistance (solvent resistance, etc.), and toner particles composed of such acrylic resin are eroded by an insulating liquid as described later in the liquid developer. And a stable dispersion state is maintained stably. However, since acrylic resins are components that exhibit negative charging characteristics (negative charging properties), toner particles composed of such acrylic resins generally exhibit negative charging properties. Therefore, it has been difficult to apply such an acrylic resin to positively charged toner particles (liquid developer). On the other hand, the colored resin fine particles (toner particles) of the present invention contain, as a constituent component, a positively chargeable amine compound having a predetermined amine value as described later in addition to an acrylic resin. By including such an amine compound in the toner particles, the liquid developer has excellent positive charging characteristics while reliably exhibiting the above-described effects obtained by using an acrylic resin. It will be excellent in efficiency. As a result, the obtained toner image has high color developability and a uniform image density. Furthermore, since such a positively chargeable amine compound is contained in the toner particles, it is possible to maintain excellent positive chargeability of the toner particles even when the liquid developer is stored for a long period of time. Can do.

  Further, the weight average molecular weight Mw of the acrylic resin contained in the toner particles is not particularly limited, but is preferably 10,000 to 180,000, and more preferably 20,000 to 150,000. As a result, an amine compound having an amine value as described below can be uniformly dispersed in the toner particles, and the positive chargeability and dispersion stability of the liquid developer are particularly excellent. In addition, the liquid developer using toner particles that are produced can more effectively prevent the occurrence of offset in the high temperature region.

  The resin material preferably has a glass transition temperature Tg of 35 to 60 ° C, more preferably 40 to 55 ° C. As a result, the liquid developer containing toner particles to be produced is more reliably prevented from agglomerating and fusing between the toner particles during storage, and the storage stability of the liquid developer is further improved. Further, the toner particles can be more suitably fixed on the recording medium at a low temperature.

The softening temperature Tf of the resin material is preferably 60 to 180 ° C, more preferably 80 to 120 ° C. As a result, the liquid developer containing toner particles to be produced is more reliably prevented from aggregating and fusing toner particles during storage, and the storage stability of the liquid developer becomes better.
In this specification, the glass transition temperature Tg is a measurement condition in a differential scanning calorimeter DSC-220C (manufactured by SII): sample amount 10 mg, temperature rising rate 10 ° C./min, measurement temperature range 10 to 150 ° C. When measured, it refers to the temperature at the intersection of an extension of the baseline below the glass transition point and a tangent that indicates the maximum slope from the peak rise to the peak apex.

The softening temperature refers to a softening start temperature defined by measurement conditions in a Koka flow tester (manufactured by Shimadzu Corporation): temperature rising rate: 5 ° C./min and die hole diameter 1.0 mm.
Examples of such acrylic resins include polyacrylic acid, polymethacrylic acid, polymethyl methacrylate, styrene-acrylic acid ester copolymer, styrene-methacrylic acid ester copolymer, styrene-acrylic acid ester-methacrylic acid. Examples include ester copolymers, styrene-α-chloroacrylic acid methyl copolymers, and styrene-acrylonitrile-acrylic acid ester copolymers.

  Further, the content of the acrylic resin in the resin material is preferably 50 wt% or more, and more preferably 80 wt% or more. Thereby, the positive charging property of the toner particles can be made sufficiently excellent, and the dispersion stability of the toner particles in the insulating liquid is particularly excellent. As a result, the formed toner image is particularly excellent in color developability and has a uniform image density. Further, the toner particles can be firmly fixed on the recording medium.

The toner particles may include a resin material other than the acrylic resin as described above.
Further, the colored resin fine particles (toner particles) of the present invention contain 0.9 to 9.1 wt% of an amine compound having an amine value of 1 to 100 mgKOH / g as a constituent component in the colored resin fine particles (toner particles).

  An amine compound having the above-described characteristics has a positive charge characteristic (positive chargeability). Such an amine compound does not simply adhere to the surface of the colored resin fine particles (toner particles) but is contained in an appropriate amount in the colored resin fine particles (toner particles), so that the negative chargeability of the acrylic resin is suitable. Therefore, the colored resin fine particles (toner particles) are excellent in positive chargeability, and the development efficiency of the liquid developer is excellent. As a result, as described above, the obtained toner image can have a uniform image density while reliably exhibiting the effects (excellent color developability, etc.) obtained by using the acrylic resin. .

  As described above, in the liquid developer described in the present embodiment, the toner particles include the acrylic resin and a predetermined amount of an amine compound having an amine value of 1 to 100 mgKOH / g as constituent components. An excellent effect can be obtained. On the other hand, when the liquid developer does not have the above-described configuration, the excellent effects as described above cannot be obtained.

  That is, if the toner particles do not contain an amine compound that satisfies the above conditions, or if the amine value of the amine compound contained in the toner particles is less than the lower limit of the above range, the toner particles are acrylic resins. The negative chargeability of the toner strongly appears and cannot be suitably used as toner particles for a positively chargeable liquid developer. Further, even if such an amine compound is contained in a large amount in the toner particles (for example, even when an amine compound having the same weight as the acrylic resin contained in the toner particles is contained in the toner particles) A sufficient positive chargeability cannot be imparted to the toner particles, and an excellent color developability of the toner image obtained by using the acrylic resin cannot be obtained.

  Further, when the amine value of the amine compound contained in the toner particles is larger than the upper limit of the above range, the toner particles are surely positively charged, but the charge amount of the toner particles becomes too large. End up. As a result, in an image forming apparatus as will be described later, the toner particles supplied from the developing roller to the photosensitive member on which the electrostatic latent image is formed are strongly adsorbed on the surface of the photosensitive member, and are preferably applied to the transfer roller. The toner image cannot be transferred, and the obtained toner image has variations in image density.

Further, when the content of the amine compound contained in the toner particles is less than the lower limit of the above range, the content of the amine compound relative to the toner particles (acrylic resin) becomes insufficient, and the toner particles are positively charged. Sex cannot be made sufficient. As a result, the obtained toner image has variations in image density.
Further, when the content of the amine compound contained in the toner particles is larger than the upper limit of the above range, the glass transition temperature of the toner particles becomes low, and an acrylic resin having excellent weather resistance can be used. Regardless, when the toner particles come into contact with each other, problems such as aggregation and fusion are likely to occur. Such an amine compound is a component that exhibits hydrophilicity. Therefore, as described above, if the content of the amine compound contained in the toner particles is excessive, a small amount of water contained in the insulating liquid permeates into the toner particles when the liquid developer is stored. It becomes easy. As a result, the dispersion stability of the liquid developer cannot be made sufficient, the positive chargeability varies among the toner particles, and the resulting toner image has a non-uniform image density. End up.

  It is also conceivable that the amine compound in the above-described range is dispersed in, for example, an insulating liquid without being included in the toner particles and adsorbed on the toner particle surfaces. However, even if such an amine compound is adsorbed on the toner particle surface, it is difficult to adsorb evenly on each toner particle, and in the image forming process, such an amine compound is not adsorbed from the toner particle surface. It is detached, and the development efficiency and transfer efficiency cannot be made sufficient.

  As described above, the amine value of such an amine compound is 1 to 100 mgKOH / g, preferably 4 to 70 mgKOH / g, and more preferably 10 to 50 mgKOH / g. Thereby, the positive chargeability of the toner particles contained in the liquid developer is particularly excellent, and the dispersion stability of the toner particles in the liquid developer is particularly excellent. As a result, a liquid developer having excellent development efficiency is obtained, and the obtained toner image has high color developability and a more uniform image density.

  Further, the content of such amine compound in the toner particles is 0.9 to 9.1 wt%, preferably 2.4 to 9.1 wt%, and 2.9 to 8.3 wt%. It is more preferable that When the content of the amine compound is within the above range, the positive chargeability of the toner particles is particularly excellent, and the dispersion stability of the toner particles in the liquid developer is particularly excellent. As a result, the development efficiency of the liquid developer is further improved.

  Further, the content of such an amine compound in the toner particles is preferably 1.2 to 13 parts by weight with respect to 100 parts by weight of the acrylic resin contained in the toner particles. More preferably, it is 5 parts by weight. When the content of the amine compound is within the above range, the positive chargeability of the toner particles is further improved, and the dispersion stability of the toner particles in the liquid developer is particularly excellent. As a result, the development efficiency of the liquid developer is further improved.

  In addition, such an amine compound preferably has a main chain having a polyester skeleton. Such an amine compound is a component having poor compatibility with an acrylic resin due to dissimilarity in chemical structure. Therefore, in the toner particles, the acrylic resin and the amine compound are phase-separated, and a sea-island structure is formed in which an aggregate of such amine compounds is unevenly distributed in the acrylic resin. As described above, when the above-described amine compound is present as an aggregate in the toner particles, the positive chargeability of the toner particles is particularly excellent. As a result, the development efficiency and transfer efficiency of the liquid developer are particularly excellent, and the resulting toner image has high color developability and a more uniform image density. Furthermore, if the amine compound contained in the toner particles has the above-described characteristics, the positive chargeability of the toner particles is sufficiently high even when the content of such an amine compound is relatively small. Can be. As a result, the effects (high color developability and the like) obtained by using the acrylic resin can be obtained more effectively while making the positive chargeability of the liquid developer sufficiently excellent.

Such an amine compound is preferably an aliphatic amine having a functional group represented by —NHR and / or —NR′R ″ (where R and R ′ are alkyl groups). The aliphatic amine as described above is a compound having weak hydrogen bonding properties as compared with an aliphatic amine in which all the functional groups contained are represented by —NH ₂ . Such amines are excellent in dispersibility in acrylic resins, and amines suitably form aggregates in toner particles (acrylic resins). Further, such an aliphatic amine has a suitable charge amount (positive charge amount) per molecule when charged. As a result, the dispersion stability of the toner particles in the liquid developer is particularly excellent, and when the toner particles are positively charged, the charge amount of the toner particles becomes more suitable. As a result, the image density of the obtained toner image can be made more uniform.

  Any amine compound may be used as long as it has an amine value as described above. Specific examples include EFKA-4008, 4009, 4010, 4046, 4300 as trade names. , 4330, 4340, 4400, 6220, 6225 (Ciba Specialty Chemicals Co., Ltd.), Addisper PB821, PB822 (Ajinomoto Fine Techno Co., Ltd.), Disperbyk-112, 116, 2000 (Bic Chemie Co., Ltd.) Etc.).

Further, the toner may contain a colorant. The colorant is not particularly limited, and for example, known pigments and dyes can be used.
Further, the toner may contain components other than those described above. Examples of such components include known waxes and magnetic powders.
In addition to the materials described above, for example, zinc stearate, zinc oxide, cerium oxide, silica, titanium oxide, iron oxide, fatty acid, fatty acid metal salt, and the like are used as toner constituent materials (components). Also good.

  Further, the toner particles as described above are preferably obtained by using a production method as described in detail later. That is, the dispersoid is united in an emulsion in which a dispersoid containing an acrylic resin that is a component of toner particles and the above-described amine compound and an organic solvent is dispersed in an aqueous dispersion medium. It is preferable that it is obtained by doing. The toner particles obtained in this manner are those in which the above-described amine compound is unevenly distributed on the outer surface side. This is considered to be due to the following reasons. That is, the amine compound contained in the dispersoid as described above is a highly hydrophilic component, and is attracted to the aqueous dispersion medium existing around the dispersoid and unevenly distributed on the outer surface side of the dispersoid. In addition, even in the process where such dispersoids coalesce, the amine compound moves to the outer surface side of the coalesced particles in the formation process, and as a result, such amine compound is unevenly distributed on the outer surface side of the toner particles. It is thought to do. Thereby, the positive chargeability of the toner particles is particularly excellent, and the development efficiency of the liquid developer is further improved. As a result, the obtained toner image has high color developability and a more uniform image density. Further, when the amine compound has a main chain of a polyester skeleton as described above, an aggregate of such amine compounds is unevenly distributed on the surface of the toner particles. Thereby, the effect as described above becomes more remarkable. In addition, the toner particles obtained in this way have a uniform particle size in which coarse particles and fine particles are not mixed. In such toner particles, the charge amount when charged becomes uniform among the toner particles, and variation in the electrophoretic speed between the toner particles is more reliably suppressed. As a result, the development efficiency and transfer efficiency of the liquid developer are improved, and the resulting toner image has a more uniform image density. Such toner particles are particularly excellent in dispersibility in the liquid developer. Therefore, when storing the liquid developer, it is possible to prevent the toner particles from unintentionally agglomerating with each other more reliably, and to ensure that there is a variation in chargeability between the toner particles over a long period of time. Can be prevented. Further, the toner particles obtained in this manner have a sufficiently small particle size (more specifically, an average particle size of 3 μm or less), as described above on the outer surface side. A more reliable amine compound can be included. As a result, it can be more suitably applied as a liquid developer for high-resolution image formation.

[Toner particle shape, etc.]
The 50% volume particle diameter Dv (50) [μm] of the toner particles composed of the above materials is not particularly limited, but is preferably 0.7 to 3 μm, and 0.8 to 2.5 μm. More preferably. When the 50% volume particle size of the toner particles is within the above range, the resolution of the toner image formed by the liquid developer can be made sufficiently high. Further, it is possible to improve the dispersion of the toner particles in the insulating liquid and to improve the storage stability of the liquid developer.

  When the 50% volume particle diameter of the toner particles is Dv (50) [μm] and the 50% number particle diameter is Dn (50) [μm], the value of Dv (50) / Dn (50) is It is preferably 1.00 to 1.12 and more preferably 1.00 to 1.10. As a result, contact and collision between toner particles can be reduced, and a decrease in charge amount due to friction between toner particles and aggregation of toner particles can be reliably prevented. Furthermore, the variation in characteristics (positive chargeability, weather resistance, body impact resistance, etc.) among the toner particles can be made sufficiently small, and the reliability of the entire liquid developer can be made higher.

The average value (average circularity) of the circularity R represented by the following formula (I) for the toner particles is preferably 0.94 to 1.00, and preferably 0.98 to 1.00. Is more preferable. When the average circularity of the toner particles is in such a range, the toner particles are more excellent in positive chargeability. In particular, variation in charge amount among toner particles is further suppressed. Thereby, the image density of the obtained toner image can be made more uniform. Further, the dispersion stability of the toner particles is particularly excellent, and the storage stability and long-term stability of the liquid developer are particularly excellent.
R = L ₀ / L ₁ (I)
(Where, L ₁ [μm] is the circumference of the projected image of the toner particles to be measured, and L ₀ [μm] is the circumference of a perfect circle having an area equal to the area of the projected image of the toner particles to be measured) Represents length)

The standard deviation of the circularity of the toner particles is preferably 0.04 or less.
As described above, when the standard deviation of the circularity is sufficiently small, the above-described effect becomes more remarkable.
Further, the variation of the toner particle diameter expressed as a numerical value (σ (DT) / DT) obtained by dividing the standard deviation (σ (DT)) of the toner particle diameter by the average particle diameter (DT) of the toner particles. The coefficient is preferably 0.30 or less, and more preferably 0.20 or less. Thereby, the particle size distribution of the toner particles becomes particularly sharp. As a result, variation in characteristics among the toner particles can be reduced, and the reliability of the entire liquid developer can be further improved.
Further, the content of toner particles in the liquid developer is preferably 10 to 60 wt%, and more preferably 20 to 50 wt%.

<Insulating liquid>
Next, the insulating liquid will be described.
In this embodiment, the insulating liquid constituting the liquid developer is not particularly limited, but a known liquid can be used as the insulating liquid. Specifically, KF96, KF4701, KF965, KS602A, KS603, KS604, KF41, KF54, FA630 (manufactured by Shin-Etsu Silicone), TSF410, TSF433, TSF434, TSF451, TSF437, (Momentive Performance Materials Japan GK) ), SH200 (manufactured by Toray Industries, Inc.), etc. Silicone oil, Isopar E, Isopar G, Isopar H, Isopar L (Exxon Chemical), Cosmo White P-60, Cosmo White P-70, Cosmo White P-120 ( Cosmo Oil Lubricants), Dyna Fresia W-8, Daphne Oil CP, Daphne Oil KP, Transformer Oil H, Transformer Oil G, Transformer Oil A, Transformer Oil B Transformer oil S (manufactured by Idemitsu Kosan), Cielsol 70, Cielsol 71 (manufactured by Ciel Oil), Amsco OMS, Amsco 460 solvent (manufactured by Spirits), low viscosity / high viscosity liquid paraffin (manufactured by Wako Pure Chemical Industries), octane , Isooctane, decane, isodecane, decalin, nonane, dodecane, isododecane, cyclohexane, cyclooctane, cyclodecane and other aliphatic hydrocarbons, fatty acid monoesters, fatty acid triglycerides, fatty acid diglycerides, fatty acid monoglycerides, glycerin, fatty acid triglycerides, etc. Decomposed products, synthetic ester liquids such as Prifer 6813 (manufactured by UNIQUEMA), benzene, toluene, xylene, mesitylene, fatty acid monoester, etc., and one or more of these In combination it can be used.

Among these, when the insulating liquid includes a fatty acid monoester, the following effects can be obtained. The fatty acid monoester is an ester between a fatty acid and a monohydric alcohol, and such a fatty acid monoester is represented by the general formula R—COO—R ′ (where R, R ′ is an alkyl group).
Fatty acid monoesters are naturally derived components and are environmentally friendly components. Therefore, it is possible to reduce the load on the environment of the insulating liquid due to leakage of the insulating liquid to the outside of the image forming apparatus and disposal of the used liquid developer. As a result, an environmentally friendly liquid developer can be provided.

  In addition, the fatty acid monoester is a liquid having a relatively low viscosity and is excellent in affinity with the acrylic resin as described above. Therefore, when the insulating liquid contains the fatty acid monoester, the dispersion stability of the toner particles in the liquid developer is excellent. As a result, inadvertent aggregation of toner particles in the liquid developer is reliably prevented, and the excellent positive chargeability of the liquid developer is maintained over a long period of time.

  The fatty acid monoester has a property of easily entering between the molecular chains of the acrylic resin, and the fatty acid monoester incorporated in the acrylic resin in this way is used to remove toner particles (acrylic resin). It has a plasticizing effect to plasticize. Therefore, the toner particles incorporating the fatty acid monoester can be easily melted and fixed on the recording medium even at a relatively low temperature. Further, the toner particles thus plasticized can be fixed more closely to the recording medium, and the fixing strength of the resulting toner image is particularly excellent. For example, when paper is used as the recording medium, the toner particles can easily enter the gaps between the paper fibers. Then, a part of the toner particles (resin material constituting the toner particles) melted by the heat at the time of fixing penetrates the inside of the recording medium, and in this state, the toner particles are allowed to cool and harden, whereby the anchor effect is obtained. The toner particles can be firmly fixed on the paper. Therefore, the liquid developer containing such toner particles has improved low-temperature fixability and excellent fixing strength of the toner particles to the recording medium.

  The fatty acid component constituting such a fatty acid monoester is represented by a general formula of R—COOH (where R is an alkyl group), and is not particularly limited. For example, oleic acid, palmitoleic acid, linoleic acid, α-linolene Unsaturated fatty acids such as acid, γ-linolenic acid, arachidonic acid, docosahexaenoic acid (DHA), eicosapentaenoic acid (EPA), butyric acid, lauric acid, caproic acid, caprylic acid, capric acid, myristic acid, palmitic acid , Saturated fatty acids represented by stearic acid, arachidic acid, behenic acid, lignoceric acid and the like, and one or more selected from these can be used in combination.

  Among these, when the fatty acid monoester contains a saturated fatty acid as a fatty acid component, the fatty acid monoester is hardly deteriorated (oxidation, decomposition, etc.) and becomes chemically particularly stable. For this reason, in the insulating liquid containing such a fatty acid monoester, deterioration phenomena such as increase in viscosity, discoloration, and decrease in electric resistance value are reliably prevented over a long period of time. In such an insulating liquid, the positive chargeability of the toner particles can be maintained over a long period of time. At the time of fixing, the fatty acid monoester is also transferred to the paper together with the toner particles, and the saturated fatty acid monoester is contained in the formed toner image. As described above, the saturated fatty acid monoester is a component that is not easily deteriorated, and even if the toner image is exposed to the external environment (light, heat, oxygen, etc.), it is reliably prevented from being discolored, and a toner image that is formed. Will be clear for a long time.

  Moreover, when a fatty acid monoester contains a saturated fatty acid as a fatty acid component, it is preferable that a C8-C20 fatty acid is included as a saturated fatty acid. Such a fatty acid monoester has excellent insulating properties and high chemical stability. As a result, when the toner particles are charged, the charge amount of each toner particle becomes more uniform, and the liquid developer has a particularly excellent development efficiency. In addition, toner particles (acrylic resin) containing such fatty acid monoesters are more suitably plasticized to make the storage stability of the liquid developer and the fixing properties of the toner particles to the recording medium particularly excellent. be able to. Further, even when a part of such fatty acid monoesters remain on the recording medium together with the toner particles, the fatty acid monoester is more reliably prevented from being deteriorated by the influence of the external environment such as light (ultraviolet rays) or heat. The color of the toner image can be made clearer over a long period of time.

  Further, such a fatty acid monoester is an ester of a fatty acid and a monohydric alcohol, and this alcohol is represented by a general formula of R—OH (where R is an alkyl group), and R has 1 carbon atom. It is preferably ~ 4. Such fatty acid monoesters suitably penetrate into the toner particles and suitably plasticize the toner particles. As a result, the storage stability of the liquid developer and the fixing characteristics of the toner particles to the recording medium can be made particularly excellent. Further, the chemical stability of the liquid developer is excellent, and the long-term stability of the liquid developer is further excellent. Further, the viscosity of the insulating liquid can be made favorable, and the penetration of the liquid developer into the recording medium can be made more suitable. Examples of such alcohol include methanol, ethanol, propanol, butanol, isobutanol and the like.

The fatty acid monoester may be produced by a transesterification reaction between a vegetable oil and a monohydric alcohol as described above. That is, the insulating liquid used in the present invention may include a fatty acid monoester obtained by combining one or more selected from fatty acids and alcohols as described above.
Examples of vegetable oils used for transesterification include soybean oil, rapeseed oil, dehydrated castor oil, tung oil, safflower oil, linseed oil, sunflower oil, corn oil, cottonseed oil, sesame oil, corn oil, cannabis oil, evening primrose oil, palm oil (Especially palm kernel oil), coconut oil, coconut oil and the like.

  Moreover, when an insulating liquid contains a fatty acid triglyceride, the following effects can be acquired. The fatty acid triglyceride is a triester (triglyceride) of glycerin and a fatty acid. That is, such a fatty acid triglyceride is an environmentally friendly component similar to the above-described fatty acid monoester, so that the insulating liquid leaks out of the image forming apparatus or the used liquid developer is discarded. The load on the environment of the liquid can be reduced. As a result, an environmentally friendly liquid developer can be provided. Moreover, fatty acid triglyceride is a component with high affinity with acrylic resin similarly to the fatty acid monoester mentioned above. Such fatty acid triglycerides have excellent electrical insulation. Therefore, in a liquid developer in which the insulating liquid contains such a fatty acid triglyceride, the dispersibility of the toner particles is further improved, and the positive chargeability and dispersion stability of the liquid developer can be improved. . Furthermore, when the insulating liquid contains such a fatty acid monoester in addition to such a fatty acid triglyceride, the following effects can be obtained. That is, such a fatty acid triglyceride is a component having a relatively higher viscosity than the fatty acid monoester. Therefore, the insulating liquid containing fatty acid triglyceride in addition to the fatty acid monoester has a more suitable viscosity, and the amount of the fatty acid monoester that penetrates into the toner particles is more suitable. As a result, the toner particles are more suitably plasticized. Further, a liquid developer having such an insulating liquid has better storage stability. This is considered as follows. In other words, in such a liquid developer, the viscosity of the insulating liquid becomes more suitable. As a result, the number of times the toner particles contact and collide with each other is reduced, so that the aggregation of the toner particles is more reliably prevented. This is thought to be due to

  The unsaturated fatty acid constituting the fatty acid triglyceride is not particularly limited, but monounsaturated fatty acids such as crotonic acid, myristoleic acid, palmitoleic acid, oleic acid, elaidic acid, vaccenic acid, gadoleic acid, erucic acid, nervonic acid, Polyunsaturated fatty acids such as linoleic acid, α-linolenic acid, γ-linolenic acid, arachidonic acid, eleostearic acid, stearidonic acid, arachidonic acid, succinic acid, docosahexaenoic acid (DHA), eicosapentaenoic acid (EPA), etc. These unsaturated fatty acids and their derivatives can be used, and one or more selected from these can be used in combination.

Such unsaturated fatty acid triglycerides are derived from various animal origins such as safflower oil, rice oil, rice bran oil, rapeseed oil, olive oil, canola oil, soybean oil, flaxseed oil, castor oil, etc. It can be efficiently obtained from naturally derived fats and oils such as fats and oils.
Moreover, the saturated fatty acid component may be contained in the fatty acid triglyceride. By including the saturated fatty acid component, it is possible to keep the chemical stability of the liquid developer and the electrical insulation of the insulating liquid even higher.

  Examples of the saturated fatty acid constituting such a saturated fatty acid component include butyric acid, caproic acid, caprylic acid, capric acid, lauric acid, myristylic acid, palmitic acid, stearic acid, arachidic acid, behenic acid, lignoceric acid and the like. These can be used alone or in combination of two or more. Among the saturated fatty acids as described above, the number of carbon atoms in the molecule is preferably 6-22, more preferably 8-20, and even more preferably 10-18. . By including a saturated fatty acid component composed of such a saturated fatty acid, the effects as described above are exhibited more significantly.

  Further, when the insulating liquid contains the aliphatic hydrocarbon as described above, the following effects can be obtained. Aliphatic hydrocarbons generally have high electrical resistance and are chemically stable. For this reason, liquid developers using aliphatic hydrocarbons have better positive chargeability, further developability and transferability, and the resulting toner images are clear, with few defects and the like. It becomes. In addition, the acrylic resin has particularly high durability (solvent resistance) against such aliphatic hydrocarbons, and even when the toner particles as described above are stored in such aliphatic hydrocarbons for a long period of time. The acrylic resin constituting the toner particles is reliably prevented from dissolving or swelling. Therefore, unintentional aggregation between toner particles and unintentional sedimentation of toner particles in the liquid developer can be more reliably prevented, and the dispersion stability of the liquid developer should be particularly excellent over a long period of time. Can do. Aliphatic hydrocarbons are liquids that absorb less moisture. For this reason, when an aliphatic hydrocarbon is contained in an insulating liquid, it can prevent suitably that an insulating liquid absorbs moisture at the time of a preservation | save, and can prevent suitably that an insulating liquid denatures (deteriorates).

  Further, when the insulating liquid contains the silicone oil as described above, the following effects can be obtained. Silicone oil is an organic compound having a siloxane bond as a skeleton. Silicone oil generally has a high electrical resistance. For this reason, when silicone oil is used as the insulating liquid, the liquid developer has better positive chargeability and further developability and transferability. Moreover, since the silicone oil has various viscosities depending on the type, the viscosity of the liquid developer can be made particularly suitable by selecting the silicone oil. Silicone oil is generally a substance that is chemically stable and has little influence on the human body. For this reason, the liquid developer can suitably prevent deterioration of the insulating liquid during storage, and has excellent environmental stability. Even when the insulating liquid leaks out of the image forming apparatus, a safe liquid developer can be obtained.

The insulating liquid may contain an antioxidant.
The liquid developer (insulating liquid) may contain a charge control agent. Thereby, the positive chargeability of the liquid developer can be further improved.
Examples of the charge control agent include metal oxides such as zinc oxide, aluminum oxide, and magnesium oxide, metal salts of benzoic acid, metal salts of salicylic acid, metal salts of alkyl salicylic acid, metal salts of catechol, metal-containing bisazo dyes, nigrosine Examples thereof include dyes, tetraphenylborate derivatives, quaternary ammonium salts, alkylpyridinium salts, chlorinated acrylics, and nitrofunnic acid.
The electric resistance of the insulating liquid at room temperature (20 ° C.) is preferably 1.0 × 10 ¹¹ Ωcm or more, more preferably 1.0 × 10 ¹² Ωcm or more, and 2.0 × 10 ^12. More preferably, it is at least Ωcm.
The dielectric constant of the insulating liquid is preferably 3.5 or less.

The viscosity of the liquid developer composed of each component as described above (viscosity measured at 25 ° C. using a vibration viscometer in accordance with JIS Z8809) is 20 to 900 mPa · s. Is more preferable, 30 to 800 mPa · s is more preferable, and 50 to 500 mPa · s is still more preferable. Thereby, since the penetration of the liquid developer into the recording medium becomes more suitable, the fixing characteristics of the toner particles to the recording medium become more excellent. In addition, the image obtained on the recording medium becomes clear with no unevenness, and is particularly suitable as a liquid developer suitable for image formation at high speed.
In addition, the electrical resistance at room temperature (20 ° C.) of the liquid developer composed of the components as described above is preferably 1.0 × 10 ¹¹ Ωcm or more, and 1.0 × 10 ¹² Ωcm or more. More preferably.

≪Method for manufacturing liquid developer (colored resin fine particle dispersion) ≫
Next, a preferred embodiment of the method for producing a liquid developer (colored resin fine particle dispersion) as described above will be described.
A manufacturing method of such a liquid developer is a dispersion in which a dispersoid containing a colorant, an acrylic resin, an amine compound having an amine value of 1 to 100 mgKOH / g, and an organic solvent is dispersed in an aqueous dispersion medium. A dispersion preparation step for preparing a mixture, a coalescence step for combining a plurality of dispersoids to obtain coalesced particles, an organic solvent contained in the coalesced particles is removed, a colorant, an acrylic resin, and an amine value Solvent removal step for obtaining colored resin fine particles (toner particles) having an amine compound of 1-100 mg KOH / g, and a dispersion step for dispersing toner particles in an insulating liquid to obtain a colored resin fine particle dispersion (liquid developer) And have. The colored resin fine particles obtained in the solvent removal step contain 0.9 to 9.1 wt% of the amine compound as described above in the colored resin fine particles.

Hereafter, each process which comprises the manufacturing method of a liquid developer is demonstrated in detail.
[Dispersion Preparation Step (Aqueous Dispersion Preparation Step)]
First, a dispersion (aqueous dispersion) is prepared.
The aqueous dispersion may be prepared by any method. For example, an acrylic resin, an amine compound having an amine value of 1 to 100 mgKOH / g, a constituent material of toner particles such as a colorant (toner material) Is dissolved and dispersed in an organic solvent to obtain a resin liquid (resin liquid preparation treatment), and an aqueous dispersion medium composed of an aqueous liquid is added to the resin liquid to thereby disperse the dispersoid containing the toner material (liquid dispersoid). ) Is formed in an aqueous liquid to obtain a dispersion (aqueous dispersion) in which the dispersoid is dispersed (dispersoid formation treatment).

(Resin liquid preparation process)
First, a resin liquid is prepared by dissolving or dispersing an acrylic resin and an amine compound having an amine value of 1 to 100 mgKOH / mg in an organic solvent.
The prepared resin liquid contains the constituent material of the toner particles as described above and the organic solvent as described below.

Any organic solvent may be used as long as it dissolves at least a part of the resin material, but it is preferable to use an organic solvent having a boiling point lower than that of the aqueous liquid described later. Thereby, the organic solvent can be easily removed.
The organic solvent is preferably one having low compatibility with an aqueous dispersion medium (aqueous liquid) described later (for example, one having a solubility in 100 g of the aqueous dispersion medium at 25 ° C. of 30 g or less). Thereby, the toner material can be finely dispersed in a stable state in the aqueous emulsion.

Further, the composition of the organic solvent can be appropriately selected according to, for example, the resin material, the composition of the colorant, the composition of the aqueous dispersion medium, and the like as described above.
Such an organic solvent is not particularly limited, and examples thereof include ketone solvents such as MEK and aromatic hydrocarbon solvents such as toluene.
Also, the amine compound as described above is suitably dissolved in the organic solvent as described above even when the main chain has a polyester skeleton. As a result, in the resin liquid (dispersoid as described later), such an amine compound is dissolved in an organic solvent, whereas in the toner particles described later, such an amine compound is contained in the toner particles. It is preferably unevenly distributed near the surface.

  The resin liquid can be obtained, for example, by mixing a material containing an acrylic resin and an amine compound having an amine value of 1 to 100 mgKOH / mg with a stirrer or the like. Examples of the stirrer that can be used for preparing the resin liquid include DESPA (manufactured by Asada Tekko Co., Ltd.), T.C. K. Robotics / T. K. Examples thereof include a high-speed stirrer such as a homodisper 2.5-type blade (manufactured by Primex).

Moreover, it is preferable that the material temperature at the time of stirring is 20-60 degreeC, and it is more preferable that it is 30-50 degreeC.
Although the content rate of solid content in a resin liquid is not specifically limited, It is preferable that it is 40-75 wt%, it is more preferable that it is 50-73 wt%, and it is further more preferable that it is 50-70 wt%. When the solid content is within the above range, the dispersoid constituting the dispersion (emulsion suspension) described later may have a higher sphericity (a shape close to a true sphere). The shape of the toner particles finally obtained can be made more surely suitable.

In the preparation of the resin liquid, all the components of the resin liquid to be prepared may be mixed at the same time, or a part of the components of the resin liquid to be prepared may be mixed in advance to prepare a mixture (master). After that, the mixture (master) may be mixed with other components.
For example, after kneading an acrylic resin and an amine compound having an amine value of 1 to 100 mgKOH / mg and a colorant to obtain a colorant master as a kneaded product, the colorant master and an acrylic resin as an additional resin The resin liquid may be prepared by mixing an organic solvent. Thereby, the resin liquid in which each component was uniformly mixed can be obtained more reliably. By using such a kneaded product, the above-described amine compound is suitably unevenly distributed on the outer surface side of the dispersoid in the aqueous dispersion described later. Therefore, the colored resin fine particles obtained by combining such dispersoids are those in which amine compounds are unevenly distributed on the outer surface side, and the positive chargeability of the toner particles can be made particularly excellent. . In addition, the liquid developer containing such toner particles has particularly excellent development efficiency, and the resulting toner image has a higher image density.
Moreover, as a constituent material (component) of the resin liquid, the above-mentioned acrylic resin precursor (for example, a prepolymer, a monomer, a dimer, a trimer, an oligomer, or the like) may be included.

(Dispersoid formation processing)
Next, an aqueous dispersion (dispersion) is prepared.
By adding an aqueous dispersion medium composed of an aqueous liquid to the resin liquid, a dispersoid containing the toner material (liquid dispersoid) is formed in the aqueous liquid, and the dispersion in which the dispersoid is dispersed (aqueous dispersion) Get. The amine compound is unevenly distributed on the outer surface side of the dispersoid thus formed. This can be explained as follows. That is, such an amine compound is a component having high affinity with the acrylic resin and the organic solvent as described above, and is also a component having affinity with the aqueous dispersion medium. That is, such an amine compound has both a hydrophobic component and a hydrophilic component. Therefore, it is considered that the amine compound contained in the dispersoid is attracted to the aqueous liquid existing around the dispersoid and is unevenly distributed on the outer surface side of the dispersoid. The coalesced particles formed by coalescence of the dispersoids thus formed are those in which an amine compound is unevenly distributed on the outer surface side, like the dispersoids. As a result, the toner particles finally obtained have excellent positive chargeability, and a liquid developer having excellent development efficiency can be obtained.

The aqueous dispersion medium is composed of an aqueous liquid.
As the aqueous liquid, a liquid mainly composed of water can be used.
The aqueous liquid may contain, for example, a solvent having excellent compatibility with water (for example, a solvent having a solubility in 100 parts by weight of water at 25 ° C. of 50 parts by weight or more).
Further, an emulsifying dispersant may be added to the aqueous dispersion medium as necessary. By adding an emulsifying dispersant, an aqueous emulsion can be prepared more easily.

The emulsifying dispersant is not particularly limited, and for example, a known emulsifying dispersant can be used.
In preparing the aqueous dispersion, for example, a neutralizing agent may be used. Thereby, for example, the functional group (ester group) possessed by the acrylic resin can be neutralized, and the shape, size uniformity, and dispersibility of the dispersoid in the prepared aqueous dispersion are particularly improved. Can be excellent. For this reason, the obtained toner particles have a particularly narrow particle size distribution.

For example, the neutralizing agent may be added to the resin liquid or may be added to the aqueous liquid.
Further, the neutralizing agent may be added in a plurality of times in the preparation of the aqueous dispersion.
As the neutralizing agent, a basic compound can be used. More specifically, for example, inorganic bases such as sodium hydroxide, potassium hydroxide, and ammonia, and organic bases such as diethylamine, triethylamine, and isopropylamine are used. 1 type selected from these, or 2 or more types can be used in combination. The neutralizing agent may be an aqueous solution containing the above compound.

  Moreover, the usage-amount of a basic compound has the preferable amount (1-3 equivalent) equivalent to 1-3 times the amount required in order to neutralize all the carboxyl groups which a resin material has, and is equivalent to 1-2 times The amount (1 to 2 equivalents) is more preferred. Thereby, it is possible to effectively prevent the formation of irregular dispersoids, and it is possible to make the particle size distribution of the particles obtained in the coalescence step described in detail later sharper.

  The aqueous liquid may be added to the resin liquid by any method, but it is preferable to add the aqueous liquid containing water to the resin liquid while stirring the resin liquid. That is, it is performed by gradually adding (dropping) an aqueous liquid into the resin liquid while applying shear to the resin liquid with a stirrer or the like, and phase-inverting from a W / O type emulsion to an O / W type emulsion. Finally, it is preferable to obtain an aqueous dispersion in which the dispersoid derived from the resin liquid is dispersed in the aqueous liquid. In the dispersoid obtained through such a method, the amine compound is surely unevenly distributed on the outer surface side. Therefore, the positive chargeability of the obtained toner particles is particularly excellent. Further, the dispersoid can be easily and reliably formed as a uniform and fine material, and the generation of coarse particles during production is particularly small. The toner particles obtained in this way have a uniform amount of charge when charged, and the variation in electrophoretic speed between the toner particles is more reliably suppressed. As a result, the development efficiency and transfer efficiency of the liquid developer are improved, and the resulting toner image has a more uniform image density.

Examples of the stirrer that can be used for the preparation of the aqueous dispersion include DESPA (manufactured by Asada Tekko Co., Ltd.), T.C. K. Robotics / T. K. Examples thereof include a high-speed stirrer such as a homodisper 2.5-type blade (manufactured by Primics), a slasher (manufactured by Mitsui Mining Co., Ltd.), a Cavitron (manufactured by Eurotech), or a high-speed disperser.
Further, at the time of adding the aqueous liquid to the resin liquid, stirring is preferably performed so that the blade tip speed is 10 to 20 m / sec, and more preferably 12 to 18 m / sec. When the blade tip speed is a value within the above range, an aqueous dispersion can be obtained efficiently, and the dispersion of the shape and size of the dispersoid in the aqueous dispersion can be made particularly small. In particular, the uniform dispersibility of the dispersoid can be made excellent while preventing the generation of fine dispersoids and coarse particles.

The solid content in the aqueous dispersion is not particularly limited, but is preferably 5 to 55 wt%, and more preferably 10 to 50 wt%. Thereby, the productivity of toner particles can be made particularly excellent while preventing unintentional aggregation of the dispersoids in the aqueous dispersion more reliably.
Moreover, it is preferable that the material temperature in this process is 20-60 degreeC, and it is more preferable that it is 20-50 degreeC.

[Joint process]
Next, a plurality of dispersoids are coalesced to obtain coalesced particles (a coalescence step). The coalescence of dispersoids usually proceeds as a result of collision of dispersoids containing an organic solvent so that they are integrated. The coalesced particles formed in this manner are those in which the amine compound is unevenly distributed on the outer surface side in the same manner as the dispersoid described above, and the positive chargeability of the finally obtained toner particles is excellent. can do.

The coalescence of a plurality of dispersoids is performed by adding an electrolyte to the dispersion while stirring the dispersion. Thereby, coalesced particles can be obtained easily and reliably. Moreover, the particle diameter and particle size distribution of the coalesced particles can be controlled easily and reliably by adjusting the amount of electrolyte added.
It does not specifically limit as electrolyte, Well-known organic and inorganic water-soluble salt etc. can be used 1 type or in combination of 2 or more types.

The electrolyte is preferably a monovalent cation salt. Thereby, the particle size distribution of the obtained coalesced particles can be narrowed. In addition, by using a monovalent cation salt, it is possible to reliably prevent generation of coarse particles in this step.
Moreover, among the above-mentioned, it is preferable that electrolyte is a sulfate (for example, sodium sulfate, ammonium sulfate) or carbonate, and it is especially preferable that it is a sulfate. Thereby, the particle diameter of the coalesced particles can be controlled particularly easily.

The amount of the electrolyte added in this step is preferably 0.5 to 3 parts by weight, preferably 1 to 2 parts by weight, based on 100 parts by weight of the solid content in the dispersion to which the electrolyte is added. Is more preferable. As a result, the particle diameter of the coalesced particles can be controlled particularly easily and reliably, and the generation of coarse particles can be reliably prevented.
The electrolyte is preferably added in the form of an aqueous solution. As a result, the electrolyte can be quickly diffused throughout the dispersion, and the amount of electrolyte added can be easily and reliably controlled. As a result, coalesced particles having a desired particle size and a particularly narrow particle size distribution can be obtained.

  Moreover, when adding electrolyte in the state of aqueous solution, it is preferable that the density | concentration of the electrolyte in aqueous solution is 2-10 wt%, and it is more preferable that it is 2.5-6 wt%. As a result, the electrolyte can be diffused through the entire dispersion particularly quickly, and the amount of electrolyte added can be easily and reliably controlled. Further, by adding such an aqueous solution, the content of water in the dispersion when the addition of the electrolyte is completed becomes suitable. For this reason, the growth rate of the coalesced particles after the addition of the electrolyte can be made moderately slow to the extent that productivity does not decrease. As a result, the amine compound can be more unevenly distributed on the outer surface side of the final colored resin fine particles (toner particles), and the particle size can be more reliably controlled. In addition, unintentional coalescence of coalesced particles can be reliably prevented.

  When the electrolyte is added as an aqueous solution, the rate of addition of the aqueous electrolyte solution is 0.5 to 10 parts by weight / minute with respect to 100 parts by weight of the solid content in the dispersion to which the aqueous electrolyte solution is added. Is preferable, and it is more preferable that it is 1.5-5 weight part / min. As a result, it is possible to prevent the uneven concentration of the electrolyte from occurring in the dispersion, and reliably prevent the generation of coarse particles. Further, the particle size distribution of the coalesced particles is particularly narrow. Furthermore, by adding the electrolyte at such a rate, the coalescing rate can be controlled particularly easily, the average particle size of the coalesced particles can be controlled particularly easily, and the toner productivity is particularly excellent. Can be.

The addition of the electrolyte may be performed in a plurality of times. As a result, coalescent particles having a desired size can be obtained easily and reliably, and the circularity of the obtained coalescent particles can be surely made sufficiently large.
Moreover, this process is performed in the state which stirred the dispersion liquid. Thereby, coalesced particles with particularly small variations in shape and size among the particles can be obtained.

  For stirring the dispersion, for example, an agitation blade such as an anchor blade, a turbine blade, a fiddler blade, a full zone blade, a max blend blade, or a half moon blade may be used, and among these, a max blend blade or a full zone blade is preferable. As a result, the added electrolyte can be quickly and uniformly dispersed and dissolved to reliably prevent the uneven concentration of the electrolyte from occurring. In addition, it is possible to more reliably prevent the coalesced particles once formed from collapsing while efficiently coalescing the dispersoid. As a result, coalesced particles with small variations in shape and particle size among the particles can be obtained efficiently.

The blade tip speed of the stirring blade is preferably from 0.1 to 10 m / second, more preferably from 0.2 to 8 m / second, and even more preferably from 0.2 to 6 m / second. When the blade tip speed is a value within the above range, the added electrolyte can be uniformly dispersed and dissolved, and the occurrence of uneven concentration of the electrolyte can be reliably prevented. In addition, it is possible to more reliably prevent the coalesced particles once formed from collapsing while more efficiently coalescing the dispersoid.
The average particle size of the obtained coalesced particles is preferably 0.1 to 7 μm, and more preferably 0.5 to 3 μm. Thereby, the particle diameter of the toner particles finally obtained can be made moderate.

[Desolvation (desolvation) step]
Thereafter, the organic solvent contained in the dispersion is removed. Thereby, colored resin fine particles (toner particles) dispersed in the dispersion are obtained.
The removal of the organic solvent may be performed by any method, but can be performed, for example, under reduced pressure. Thereby, the organic solvent can be efficiently removed while sufficiently preventing the modification of the constituent material such as the resin material.

Moreover, it is preferable that the process temperature in this process is temperature lower than the glass transition point (Tg) of the resin material which comprises coalesced particle.
Moreover, you may perform this process in the state which added the antifoamer to the dispersion liquid. Thereby, an organic solvent can be removed efficiently.
Antifoaming agents include, for example, mineral oil-based antifoaming agents, polyether-based antifoaming agents, silicone-based antifoaming agents, lower alcohols, higher alcohols, fats and oils, fatty acids, fatty acid esters, phosphoric acid Esters can be used.

Although the usage-amount of an antifoamer is not specifically limited, It is preferable that it is 20-300 ppm by weight ratio with respect to the solid content contained in a dispersion liquid, and it is more preferable that it is 30-100 ppm.
In this step, at least a part of the aqueous liquid may be removed together with the organic solvent.
In this step, it is not always necessary to remove all of the organic solvent (the total amount of the organic solvent contained in the dispersion). Even in such a case, the remaining organic solvent can be sufficiently removed in other steps described later.

[Washing process]
Next, the colored resin fine particles (toner particles) obtained as described above are washed (cleaning step).
By performing this step, even if an organic solvent or the like is contained as an impurity, these can be efficiently removed. As a result, the amount of volatile organic compound (TVOC) in the colored resin fine particles finally obtained can be made particularly small.
In this step, for example, the colored resin fine particles are separated by solid-liquid separation (separation from the aqueous liquid), and then the solid content (colored resin fine particles) is redispersed in water and solid-liquid separation (coloration from the aqueous liquid). It can be carried out by separating resin fine particles. The redispersion of solids in water and solid-liquid separation may be repeated a plurality of times.

[Drying process]
Thereafter, toner particles can be obtained by performing a drying process (drying step).
The drying step can be performed using, for example, a vacuum dryer (for example, ribocorn (manufactured by Okawara Seisakusho), nauter (manufactured by Hosokawa Micron) etc.), fluidized bed dryer (manufactured by Okawara Seisakusho), etc.

[Dispersion process]
Next, the toner particles obtained as described above are dispersed in an insulating liquid. Thereby, a liquid developer is obtained.
As such an insulating liquid, the insulating liquid as described above can be used.
The toner particles can be dispersed in the insulating liquid by any method, for example, by mixing the insulating liquid and the toner particles with a bead mill, a ball mill, or the like.

In addition, components other than the insulating liquid and toner particles may be mixed during the dispersion.
Further, the dispersion of the toner particles in the insulating liquid may be performed by using the whole amount of the insulating liquid constituting the finally obtained liquid developer, or by using a part of the insulating liquid. It may be a thing.

  Further, when the toner particles are dispersed using a part of the insulating liquid, the same liquid as the liquid used for the dispersion may be added as the insulating liquid after the dispersion, or after the dispersion, Alternatively, a liquid different from the liquid used for dispersion may be added as an insulating liquid. In the latter case, characteristics such as the viscosity of the finally obtained liquid developer can be easily adjusted.

≪Image forming device≫
Next, a preferred embodiment of an image forming apparatus to which the liquid developer as described above can be applied will be described. Such an image forming apparatus forms a color image on a recording medium using a liquid developer as described above.
FIG. 1 is a schematic view showing an example of an image forming apparatus to which the liquid developer as described above is applied, FIG. 2 is an enlarged view of a part of the image forming apparatus shown in FIG. 1, and FIG. FIG. 4 is a cross-sectional view showing an example of a fixing device applied to the image forming apparatus shown in FIG. 1.

As shown in FIGS. 1 and 2, the image forming apparatus 1000 includes four developing units 30Y, 30M, 30C, and 30K, an intermediate transfer unit 40, a secondary transfer unit (secondary transfer unit) 60, and a fixing unit. (Fixing device) F40 and four liquid developer supply portions 80Y, 80M, 80C, and 80K are provided.
The developing units 30Y, 30M, and 30C develop a latent image with a yellow liquid developer (Y), a magenta liquid developer (M), and a cyan liquid developer (C), respectively, and correspond to each color. It has a function of forming a single color image. The developing unit 30K has a function of developing a latent image with a black liquid developer (K) to form a black single color image.

Since the developing units 30Y, 30M, 30C, and 30K have the same configuration, the developing unit 30Y will be described below.
As shown in FIG. 2, the developing unit 30Y includes a photoconductor 10Y as an example of an image carrier, a charging roller 11Y, an exposure unit 12Y, a development unit 100Y, and a photoconductor along the rotation direction of the photoconductor 10Y. The image forming apparatus includes a body squeeze device 101Y, a primary transfer backup roller 51Y, a charge removal unit 16Y, a photoreceptor cleaning blade 17Y, and a developer recovery unit 18Y.

The photoreceptor 10Y has a cylindrical base material and a photosensitive layer formed on the outer peripheral surface thereof, and can rotate around a central axis. In this embodiment, as shown by an arrow in FIG. Rotate clockwise.
The photoreceptor 10Y is supplied with a liquid developer by a developing unit 100Y described later, and a layer of the liquid developer is formed on the surface.

  The charging roller 11Y is a device for charging the photoconductor 10Y, and the exposure unit 12Y is a device for forming a latent image on the photoconductor 10Y charged by irradiating a laser. The exposure unit 12Y includes a semiconductor laser, a polygon mirror, an F-θ lens, and the like, and charges a modulated laser based on an image signal input from a host computer (not shown) such as a personal computer or a word processor. Irradiate onto the photoconductor 10Y.

The developing unit 100Y is an apparatus for developing the latent image formed on the photoreceptor 10Y using the liquid developer as described above. Details of the developing unit 100Y will be described later.
The photoconductor squeeze device 101Y is disposed on the downstream side of the developing unit 100Y in the rotation direction so as to face the photoconductor 10Y. The photoconductor squeeze roller 13Y and the photoconductor squeeze roller 13Y are pressed and slidably attached to the surface. The cleaning blade 14Y removes the liquid developer and the developer collection unit 15Y that collects the removed liquid developer. The photoreceptor squeeze device 101Y has a function of collecting excess carrier (insulating liquid) and originally unnecessary fog toner from the developer developed on the photoreceptor 10Y, and increasing the ratio of toner particles in the visible image.

The primary transfer backup roller 51Y is a device for transferring a single color image formed on the photoreceptor 10Y to an intermediate transfer unit 40 described later.
The neutralization unit 16Y is a device that removes residual charges on the photoreceptor 10Y after the intermediate transfer image is transferred onto the intermediate transfer unit 40 by the primary transfer backup roller 51Y.
The photoconductor cleaning blade 17Y is a rubber member that is in contact with the surface of the photoconductor 10Y, and remains on the photoconductor 10Y after the image is transferred onto the intermediate transfer portion 40 by the primary transfer backup roller 51Y. It has a function of scraping off and removing the liquid developer.

The developer recovery unit 18Y has a function of recovering the liquid developer removed by the photoconductor cleaning blade 17Y.
The intermediate transfer unit 40 is an endless elastic belt member, is wound around a belt driving roller 41 and a tension roller 42, and is stretched by the primary transfer backup rollers 51Y, 51M, 51C, and 51K. It is rotationally driven by the driving roller 41 while contacting with 10M, 10C, 10K.

A single color image corresponding to each color formed by the developing units 30Y, 30M, 30C, and 30K is sequentially transferred to the intermediate transfer unit 40 by the primary transfer backup rollers 51Y, 51M, 51C, and 51K, and a single color corresponding to each color is transferred. The images are superimposed. As a result, a full-color developer image (intermediate transfer image) is formed on the intermediate transfer portion 40.
In the intermediate transfer unit 40, the single-color images formed on the plurality of photoconductors 10Y, 10M, 10C, and 10K are secondarily transferred and superposed one after another, and recorded on paper, film, cloth, and the like in a lump. Secondary transfer is performed on the medium F5. Therefore, when the toner image is transferred to the recording medium F5 in the secondary transfer process, even if the surface of the recording medium F5 is a sheet material that is not smooth due to fiber or the like, the secondary transfer characteristics follow the surface of the non-smooth sheet material. An elastic belt member is employed as means for improving the above.

A cleaning device including an intermediate transfer unit cleaning blade 46 and a developer recovery unit 47 is disposed on the tension roller 42 side that stretches the intermediate transfer unit 40 together with the belt drive roller 41.
The intermediate transfer portion cleaning blade 46 has a function of scraping and removing the liquid developer adhering to the intermediate transfer portion 40 after the image is transferred onto the recording medium F5 by the secondary transfer roller 61.

The developer recovery unit 47 has a function of recovering the liquid developer removed by the intermediate transfer unit cleaning blade 46.
An intermediate transfer unit squeeze device 52Y is disposed downstream of the primary transfer backup roller 51Y in the moving direction of the intermediate transfer unit 40.
The intermediate transfer unit squeeze device 52Y is provided as a means for removing excess insulating liquid from the transferred liquid developer when the liquid developer transferred onto the intermediate transfer unit 40 has not reached the desired dispersion state. ing.

  The intermediate transfer unit squeeze device 52Y includes an intermediate transfer unit squeeze roller 53Y, an intermediate transfer unit squeeze backup roller 54Y disposed opposite to the intermediate transfer unit squeeze roller 53Y with the intermediate transfer unit 40 interposed therebetween, and an intermediate transfer unit squeeze roller 53Y. It comprises an intermediate transfer unit squeeze cleaning blade 55Y that cleans the surface by pressing and sliding, and a developer recovery unit 15M.

  The intermediate transfer unit squeeze device 52Y has a function of recovering excess carrier from the developer primarily transferred to the intermediate transfer unit 40, increasing the toner particle ratio in the visible image, and recovering originally unwanted toner. . The developer recovery unit 15M uses a mechanism for recovering the carrier recovered by the cleaning blade 14M of the magenta photosensitive member squeeze roller disposed downstream in the moving direction of the intermediate transfer unit 40. The developer transfer unit squeeze the intermediate transfer unit squeeze roller 53Y. This is also used for the cleaning blade 55Y. In this way, in the developer collection units 15M, 15C, and 15K (developer collection units 15C and 15K are not shown) of the image carrier squeeze device for the second and subsequent colors, the primary transfer backup roller 51 of the previous color ( Y, M, C) is used as a developer recovery unit of the intermediate transfer unit squeeze device 52 (Y, M, C) disposed downstream of the intermediate transfer unit 40 in the moving direction, so that the interval between them is constant. It can be regulated, and the structure can be simplified and the size can be reduced.

The secondary transfer unit 60 includes a cleaning device including a secondary transfer roller 61 facing the belt driving roller 41 with the intermediate transfer unit 40 interposed therebetween, and a cleaning device including a cleaning blade 62 and a developer recovery unit 63 of the secondary transfer roller 61. Be placed.
In the secondary transfer unit 60, the recording medium F5 is conveyed and supplied in accordance with the timing at which the intermediate transfer image formed on the intermediate transfer unit 40 by overlapping colors reaches the transfer position of the secondary transfer unit 60. The intermediate transfer image is secondarily transferred to the recording medium F5.

The toner image (transfer image) F5a transferred onto the recording medium F5 by the secondary transfer unit 60 is sent to a fixing unit F40, which will be described later, and is fixed.
The cleaning blade 62 has a function of scraping and removing the liquid developer adhering to the secondary transfer roller 61 after the image is transferred onto the recording medium F5 by the secondary transfer roller 61.
The developer recovery unit 63 has a function of recovering the liquid developer removed by the cleaning blade 62.

Next, the developing units 100Y, 100M, 100C, and 100K will be described in detail. In the following description, the developing unit 100Y will be typically described.
As shown in FIG. 2, the developing unit 100Y includes a liquid developer storage unit 31Y, a coating roller 32Y, a regulating blade 33Y, a developer stirring roller 34Y, a developing roller 20Y, a developing roller cleaning blade 21Y, and a developing unit. And an agent compression roller (compression means) 22Y.

The liquid developer storage unit 31Y has a function of storing a liquid developer for developing the latent image formed on the photoreceptor 10Y.
The coating roller 32Y has a function of supplying a liquid developer to the developing roller 20Y.
The application roller 32Y is a so-called anilox roller in which grooves are uniformly and spirally formed on the surface of a metallic roller such as iron and nickel-plated, and has a diameter of about 25 mm. . In the present embodiment, a plurality of grooves are formed obliquely with respect to the rotation direction of the application roller 32Y by so-called cutting or rolling. The application roller 32Y contacts the liquid developer while rotating clockwise, thereby supporting the liquid developer in the liquid developer storage section 31Y in the groove, and the supported liquid developer is transferred to the developing roller 20Y. Transport to.

  The regulating blade 33Y is in contact with the surface of the coating roller 32Y and regulates the amount of liquid developer on the coating roller 32Y. That is, the regulation blade 33Y plays a role of scraping off the excess liquid developer on the application roller 32Y and measuring the liquid developer on the application roller 32Y supplied to the development roller 20Y. The restriction blade 33Y is made of urethane rubber as an elastic body, and is supported by a restriction blade support member made of metal such as iron. Further, the regulating blade 33Y is provided on the side where the coating roller 32Y rotates and advances from the liquid developer as viewed from the vertical surface A (that is, the left side in FIG. 2 as viewed from the vertical surface A). The rubber hardness of the regulation blade 33Y is about 77 degrees according to JIS-A, and the hardness (about 77 degrees) of the contact portion of the regulation blade 33Y with the surface of the coating roller 32Y is about the elasticity of the developing roller 20Y described later. It is lower than the hardness (about 85 degrees) of the pressure contact portion of the body layer to the surface of the application roller 32Y. Further, the excess liquid developer scraped off is collected in the liquid developer storage unit 31Y and reused.

The developer stirring roller 34Y has a function of stirring the liquid developer in a uniformly dispersed state. Thus, even when a plurality of toner particles 1 are aggregated, the toner particles 1 can be suitably dispersed. In particular, the toner particles 1 can be suitably dispersed even when the liquid developer once used is reused.
In the liquid developer storage unit 31Y, the toner particles 1 in the liquid developer have a positive charge, and the liquid developer is stirred by the developer stirring roller 34Y to be in a uniformly dispersed state, and the coating roller 32Y. , The liquid developer is stored in the liquid developer reservoir 31Y, and the amount of liquid developer is regulated by the regulating blade 33Y and supplied to the developing roller 20Y.

The developing roller 20Y carries the liquid developer and conveys it to the developing position facing the photoconductor 10Y in order to develop the latent image carried on the photoconductor 10Y with the liquid developer.
The developing roller 20Y forms a liquid developer layer 201Y on the surface thereof by supplying the liquid developer from the coating roller 32Y described above.
The developing roller 20Y includes a conductive elastic layer on the outer peripheral portion of an inner core made of metal such as iron, and has a diameter of about 20 mm. The elastic layer has a two-layer structure. As an inner layer thereof, urethane rubber having a rubber hardness q degree of about 30 degrees and a thickness of about 5 mm is used as a surface layer (outer layer) of rubber hardness. Is provided with urethane rubber having a JIS-A of about 85 degrees and a thickness of about 30 μm. The developing roller 20Y is in pressure contact with the coating roller 32Y and the photoreceptor 10Y in a state of being elastically deformed with the surface layer serving as a pressure contact portion.

  Further, the developing roller 20Y can rotate around its central axis, and the central axis is below the rotational central axis of the photoconductor 10Y. Further, the developing roller 20Y rotates in a direction (counterclockwise in FIG. 2) opposite to the rotation direction of the photoreceptor 10Y (clockwise in FIG. 2). When developing the latent image formed on the photoconductor 10Y, an electric field is formed between the developing roller 20Y and the photoconductor 10Y.

  The developer compression roller 22Y is a device having a function of compressing the liquid developer toner carried on the development roller 20Y. In other words, the developer compression roller 22Y applies an electric field having the same polarity as the toner particles 1 to the liquid developer layer 201Y described above, thereby developing the liquid developer layer 201Y in the liquid developer layer 201Y as shown in FIG. This is a device having a function of unevenly distributing the toner particles 1 near the surface of the roller 20Y. By unevenly distributing the toner particles in this way, the development density (development efficiency) can be improved, and as a result, a clear image with high quality can be obtained.

The developer compression roller 22Y is provided with a cleaning blade 23Y.
The cleaning blade 23Y has a function of removing the liquid developer adhering to the developer compression roller 22Y. The liquid developer removed by the cleaning blade 23Y is collected in the liquid developer reservoir 31Y and reused.
The developing unit 100Y includes a rubber developing roller cleaning blade 21Y that is in contact with the surface of the developing roller 20Y. The developing roller cleaning blade 21Y is a device for scraping off and removing the liquid developer remaining on the developing roller 20Y after development is performed at the developing position. The liquid developer removed by the developing roller cleaning blade 21Y is collected in the liquid developer reservoir 31Y and reused.

As shown in FIGS. 1 and 2, the image forming apparatus 1000 includes liquid developer replenishing sections 80Y, 80M, 80C, and 80K that replenish liquid developer to the developing section 30Y. Since the configurations of the liquid developer supply portions 80Y, 80M, 80C, and 80K are the same, the liquid developer supply portion 80Y will be described below.
The liquid developer supply unit 80Y includes a recovered liquid developer storage unit 81Y, a supply liquid developer storage unit 82Y, transport means 83Y and 84Y, a pump 85Y, and a filter 86Y.

  The recovered liquid developer storage unit 81Y mainly stores the recovered liquid developer recovered by the developer recovery unit 18Y, and supplies the recovered liquid developer to the liquid developer storage unit 31Y of the developing unit 30Y by the transport unit 83Y. . In addition, the liquid developer is stored in the replenishment liquid developer storage portion 82Y, and the liquid developer is supplied to the liquid developer storage portion 31Y by the transport means 84Y. The composition of the liquid developer stored in the replenishment liquid developer storage portion 82Y and the composition of the recovered liquid developer stored in the recovered liquid developer storage portion 81Y are the same as the liquid developer stored in the liquid developer storage portion 31Y. It may be different or different.

Further, the liquid developer collected in the developer collecting unit 18Y is supplied to the liquid developer replenishing unit 80Y through the conveyance path 70Y.
The transport path 70Y is provided with a pump 85Y. The pump 85Y transports the liquid developer recovered by each developer recovery section to the recovered liquid developer storage section 81Y.
Further, a filter 86Y is provided in the conveyance path 70Y, and coarse particles, foreign matter, and the like can be removed from the collected liquid developer. Solid content such as coarse particles and foreign matter removed by the filter 86Y is detected by a filter state detection means (not shown). Then, the filter 86Y is replaced based on the detection result. Thereby, the filtering function of the filter 86Y can be stably maintained.

Next, the fixing unit will be described.
The fixing unit F40 fixes the unfixed toner image F5a formed in the above-described developing unit, transfer unit, and the like on the recording medium F5.
As shown in FIG. 4, the fixing unit F40 includes a heat fixing roller F1, a pressure roller F2, a heat-resistant belt F3, a belt stretching member F4, a cleaning member F6, a frame F7, and a spring F9. is doing.

The heat fixing roller (fixing roller) F1 includes a roller base material F1b made of a pipe material, an elastic body F1c covering the outer periphery thereof, and a columnar halogen lamp F1a as a heating source inside the roller base material F1b. It can be rotated counterclockwise as indicated by an arrow in the figure.
Inside the heat fixing roller F1, two columnar halogen lamps F1a and F1a constituting a heating source are incorporated, and the heating elements of these columnar halogen lamps F1a and F1a are arranged at different positions. Yes. Then, by selectively lighting each columnar halogen lamp F1a, F1a, a fixing nip portion where a heat-resistant belt F3, which will be described later, is wound around the heat-fixing roller F1, and a belt stretching member F4, which will be described later, are attached to the heat-fixing roller F1. The temperature controller is easily performed under different conditions from the sliding contact portion, different conditions between the wide recording medium and the narrow recording medium, or the like.

The pressure roller F2 is arranged to face the heat fixing roller F1, and is configured to apply pressure to the recording medium F5 on which the unfixed toner image F5a is formed via a heat-resistant belt F3 described later. Has been.
The pressure roller F2 includes a roller base material F2b made of a pipe material and an elastic body F2c covering the outer periphery thereof, and is rotatable in the clockwise direction indicated by an arrow in the drawing.

A PFA layer is provided on the surface layer of the elastic body F1c of the heat fixing roller F1. As a result, the elastic bodies F1c and 2c have different thicknesses, but the elastic bodies F1c and 2c are substantially uniformly elastically deformed to form a so-called horizontal nip, and with respect to the peripheral speed of the heat fixing roller F1. Since there is no difference in the conveyance speed of the heat-resistant belt F3 or the recording medium F5, which will be described later, extremely stable image fixing is possible.
The heat-resistant belt F3 is an endless annular belt that is stretched around the outer periphery of the pressure roller F2 and the belt stretching member F4 and is movable, and is sandwiched between the heat fixing roller F1 and the pressure roller F2. is there.

  The heat-resistant belt F3 has a thickness of 0.03 mm or more, and its front surface (the surface on which the recording medium F5 comes into contact) is formed of PFA, and the rear surface (the pressure roller F2 and the belt stretching member F4 is in contact). The side surface is formed of a seamless tube having a two-layer structure formed of polyimide. The heat-resistant belt F3 is not limited to this, and can be formed of other materials such as a metal tube such as a stainless steel tube or a nickel electroformed tube, or a heat-resistant resin tube such as silicone.

The belt stretching member F4 is disposed upstream of the fixing nip portion between the heat fixing roller F1 and the pressure roller F2 in the conveyance direction of the recording medium F5, and has an arrow P around the rotation axis F2a of the pressure roller F2. It is arranged so that it can swing in the direction.
The belt stretching member F4 is configured to stretch the heat-resistant belt F3 in the tangential direction of the heat fixing roller F1 in a state where the recording medium F5 does not pass through the fixing nip portion. If the fixing pressure is large at the initial position where the recording medium F5 enters the fixing nip portion, the entry may not be smoothly performed and the recording medium F5 may be fixed in a state where the tip of the recording medium F5 is broken. By adopting a configuration in which F3 is stretched in the tangential direction of the heat fixing roller F1, an inlet port of the recording medium F5 through which the recording medium F5 enters smoothly can be formed, and the stable fixing nip portion of the recording medium F5 can be formed. Can enter.

  The belt stretching member F4 is fitted into the inner periphery of the heat-resistant belt F3 and cooperates with the pressure roller F2 to apply a tension f to the heat-resistant belt F3 (a heat-resistant belt F3 is a belt). Sliding on the tension member F4). This belt stretching member F4 is disposed at a position where the heat-resistant belt F3 is wound around the heat fixing roller F1 side from the pressing portion tangent L between the heat fixing roller F1 and the pressure roller F2 to form a nip. The protruding wall F4a protrudes from one end or both ends of the belt stretching member F4 in the axial direction. The protruding wall F4a is formed by the heat-resistant belt F3 when the heat-resistant belt F3 approaches one of the axial ends. The contact to the end of the heat-resistant belt F3 is regulated by contacting the wall F4a. A spring F9 is contracted between the end of the protruding wall F4a opposite to the heat fixing roller F1 and the frame, and the protruding wall F4a of the belt stretching member F4 is lightly pressed by the heat fixing roller F1, so that the belt tension is increased. The frame member F4 is positioned in sliding contact with the heat fixing roller F1.

The position where the belt stretching member F4 is lightly pressed against the heat fixing roller F1 is the nip initial position, and the position where the pressure roller F2 is pressed against the heat fixing roller F1 is the nip end position.
In the fixing portion F40, the recording medium F5 on which the unfixed toner image F5a is formed enters the fixing nip portion from the nip initial position and passes between the heat-resistant belt F3 and the heat fixing roller F1, and the nip end position. As a result, the unfixed toner image F5a formed on the recording medium F5 is fixed, and then discharged in the tangential direction L of the pressing portion of the pressure roller F2 to the heat fixing roller F1.

The cleaning member F6 is disposed between the pressure roller F2 and the belt stretching member F4.
The cleaning member F6 is in sliding contact with the inner peripheral surface of the heat-resistant belt F3 to clean foreign matter, abrasion powder, and the like on the inner peripheral surface of the heat-resistant belt F3. By cleaning the foreign matter, wear powder, and the like in this way, the heat-resistant belt F3 is refreshed, and the above-described factor of instability of the friction coefficient is removed. Further, the belt stretching member F4 is provided with a recess F4f, and is configured to store foreign matter, abrasion powder, and the like removed from the heat-resistant belt F3.

  The fixing unit F40 has a removing blade (removing means) F12 that removes the insulating liquid adhering (remaining) to the surface of the heat fixing roller F1 after fixing the toner image F5a on the recording medium F5. . The removing blade F12 can remove the insulating liquid and simultaneously remove the toner and the like that have moved onto the heat fixing roller F1 during fixing.

  In order to stably drive the heat-resistant belt F3 by the pressure roller F2 and the belt stretching member F4 and stably drive the pressure roller F2, the friction coefficient between the pressure roller F2 and the heat-resistant belt F3 is determined by the belt tension. It is good to set larger than the friction coefficient of the frame member F4 and the heat-resistant belt F3. However, the friction coefficient is such that foreign matter enters between the heat-resistant belt F3 and the pressure roller F2 or between the heat-resistant belt F3 and the belt stretching member F4, or the heat-resistant belt F3, the pressure roller F2, and the belt stretching member. It may become unstable due to wear of the contact portion with F4.

  Therefore, the belt tension member F4 and the heat-resistant belt F3 have a winding angle smaller than the winding angle of the pressure roller F2 and the heat-resistant belt F3, and the diameter of the belt stretching member F4 is smaller than the diameter of the pressure roller F2. Set as follows. As a result, the length that the heat-resistant belt F3 slides on the belt stretching member F4 is shortened, which can be avoided from instability factors such as changes with time and disturbances, and the heat-resistant belt F3 is driven stably by the pressure roller F2. Will be able to.

  Specifically, the heat (fixing temperature) applied by the heat fixing roller F1 is preferably 80 to 200 ° C, more preferably 100 to 180 ° C, and further preferably 100 to 150 ° C. Since the liquid developer as described above is excellent in fixability at a low temperature, the toner image can be firmly fixed on the recording medium even at a relatively low fixing temperature.

As mentioned above, although this invention was demonstrated based on suitable embodiment, this invention is not limited to these.
For example, the use of the colored resin fine particles of the present invention is not limited to the toner particles for liquid developer as described above, and includes toner particles for dry toner, electrophoretic particles for electrophoretic display devices, and the like. .

  Electrophoretic particles for electrophoretic display devices generally require both positively charged electrophoretic particles and negatively charged electrophoretic particles, and the colored resin fine particles of the present invention are positively charged. It can be used as electrophoretic particles. By the way, as such electrophoretic particles, there is an attempt to use particles obtained by pulverizing a kneaded mixture of a pigment and a resin for the purpose of improving the dispersibility in the electrophoretic particle dispersion. When an acrylic resin is used as a resin material constituting such particles, it is difficult to sufficiently positively charge, and as a result, there is a problem that sufficient contrast of a displayed image cannot be obtained. It was. On the other hand, by using the colored resin fine particles having the above-described characteristics as positively charged electrophoretic particles, the electrophoretic particles can be obtained by using an acrylic resin, and have excellent color developability and excellent It has positive chargeability. Further, as described above, such an acrylic resin is excellent in weather resistance (solvent resistance). For example, electrophoretic particles are electrophoresed in the insulating liquid as described above, and an image is displayed. In such an electrophoretic display device, the dispersion stability of the electrophoretic particles in the insulating liquid is excellent. As a result, the display image of the electrophoretic display device is clear with excellent contrast. Further, the electrophoretic particle dispersion liquid in which the electrophoretic particles are dispersed in the insulating liquid, which is obtained by using the method for producing the colored resin fine particle dispersion liquid (in the above-described embodiment, the liquid developer) as described above is included. The particle diameter of the electrophoretic particles is particularly uniform, and the variation in charging characteristics among the electrophoretic particles can be made sufficiently small. When a voltage is applied to the thus obtained electrophoretic particle dispersion, each electrophoretic particle is electrophoresed at a uniform speed, and a clear image display with a clearer contrast can be achieved.

Further, the liquid developer as described above is not limited to those applied to the liquid developer and the fixing device as described above.
Further, the liquid developer as described above is not limited to the one manufactured by the manufacturing method as described above.
In the above-described embodiment, the aqueous dispersion liquid is obtained, and the coalescent particles are obtained by adding the electrolyte to the aqueous emulsion liquid. However, the present invention is not limited to this. For example, in the coalesced particles as described above, a colorant, a monomer, a surfactant, and a polymerization initiator are dispersed in an aqueous liquid, an aqueous dispersion is prepared by emulsion polymerization, and an electrolyte is added to the aqueous dispersion. The emulsion may be prepared by an emulsion polymerization association method in which the particles are added and associated, or may be obtained by spray drying the obtained aqueous dispersion to obtain coalesced particles.

[1] Production of liquid developer (Example 1)
First, toner particles were manufactured. In addition, about the process in which temperature is not described, it performed at room temperature (25 degreeC).
<Dispersion adjustment process>
(Preparation of colorant master solution)
First, styrene-acrylic copolymer R1 (acid value: 12.0 KOHmg / g, weight average molecular weight Mw: 30,000, glass transition temperature Tg: 55 ° C., softening temperature Tf: 120 ° C.) as an acrylic resin, coloring A mixture (mass ratio R1: cyan pigment = 50: 50) with a cyan pigment (manufactured by Dainichi Seika Co., Ltd., Pigment Blue 15: 3) was prepared. These components were mixed using a 20 L type Henschel mixer to obtain a raw material for toner production.

Next, this raw material (mixture) was kneaded using a twin-screw kneading extruder. The kneaded product extruded from the extrusion port of the biaxial kneading extruder was cooled.
The kneaded product cooled as described above was coarsely pulverized to obtain a powder having an average particle size of 1.0 mm or less. A hammer mill was used for coarse pulverization of the kneaded product.
Methyl ethyl ketone was added to the obtained kneaded powder so that the solid content was 30% by mass, and wet dispersion was performed with an Eiger motor mill (manufactured by Eiger, USA: M-1000) to prepare a colorant master solution.

(Resin liquid preparation process)
The above colorant master solution: 139.2 parts by weight, methyl ethyl ketone: 3.4 parts by weight, acrylic resin R1: 91.8 parts by weight, amine compound EFKA-6220 (manufactured by Ciba Specialty Chemicals Co., Ltd., amine value) : 35.0 mg KOH / g, acid value: 22.0 mg KOH / g): 5.6 parts by weight and Neogen SC-F (Daiichi Kogyo Seiyaku Co., Ltd.) as an emulsifier: 1.1 parts by weight are added, and high speed dispersion is performed. The resin solution was prepared by mixing with a machine (Primics Co., Ltd., TK Robotics / TK homodisper type 2.5 blade). In this solution, the pigment was uniformly finely dispersed. At this time, the solid content of the resin liquid was 58%.

(Dispersoid formation processing)
Next, 28.7 parts by weight of 1N ammonia water was added to the resin liquid in the container, and the mixture was stirred with a high-speed disperser (Primics Co., Ltd., TK Robotics / TK homodisper type 2.5 blade). The blade tip speed of the blade was sufficiently stirred at 7.5 m / s, the temperature of the solution in the flask was adjusted to 25 ° C., and then the stirring blade blade speed was 14.7 m / s while stirring. Part by weight of deionized water was added dropwise to cause phase inversion emulsification. While continuing stirring, 70 parts by weight of deionized water was further added to the resin solution. As a result, an aqueous dispersion in which the dispersoid containing the resin material was dispersed was obtained.

<Joint process>
Next, the aqueous dispersion was transferred to a stirring vessel having a Max Blend blade, and the temperature of the aqueous dispersion was adjusted to 25 ° C. while stirring at a blade tip speed of 1.0 m / s.
Next, while maintaining the same temperature and stirring conditions, a 5.0% ammonium sulfate aqueous solution: 300 parts by weight was dropped, and the dispersoids were coalesced to form coalesced particles. After the dropping, stirring was continued until the 50% volume particle diameter Dv (50) [μm] of the coalesced toner particles grew to 2.5 μm. When the Dv (50) of the coalesced particles reached 2.5 μm, 200 parts by weight of deionized water was added to complete the coalescence. The 50% volume particle diameter Dv (50) [μm] of the obtained particles was measured with a Mastersizer 2000 particle analyzer (manufactured by Malvern Instruments Ltd.).

<Desolvation process>
The organic solvent was distilled off under reduced pressure until the solid content was 23 wt%, to obtain a slurry of colored resin fine particles.
<Washing process>
Next, the slurry was subjected to solid-liquid separation, and further subjected to washing treatment by redispersion in water (reslurry) and repeated solid-liquid separation. Thereafter, a wet cake (resin fine particle cake) of colored resin fine particles was obtained by suction filtration. The moisture content of the wet cake was 35 wt%.

<Drying process>
Thereafter, the obtained wet cake was dried using a vacuum dryer to obtain toner particles. Further, when the 50% volume particle diameter of the toner particles is Dv (50) [μm] and the 50% number particle diameter is Dn (50) [μm], Dv (50) is 2.4 μm and Dv ( 50) / Dn (50) was 1.09. The 50% volume particle size Dv (50) [μm] and the 50% number particle size Dn (50) [μm] of the obtained particles are the above-mentioned Mastersizer 2000 particle analyzer (manufactured by Malvern Instruments Ltd.). Measurements were made at Moreover, the particle size (Dv (50)) and the particle size distribution (Dv (50) / Dn (50)) were similarly determined for the particles obtained in each Example and each Comparative Example described below.

<Dispersing process>
Toner particles obtained by the above method: 40 parts by weight, soybean oil transesterification liquid produced by a transesterification reaction between soybean oil and methanol (viscosity 5.1 mPa · s, manufactured by Nisshin Oilio Co., Ltd., trade name “Large” Soybean oil fatty acid methyl "): 60 parts by weight, and high oleic rapeseed oil (Nisshin Oilio Co., Ltd., trade name" high oleic rapeseed oil "): 90 parts by weight are placed in a ceramic pot (internal volume 600 ml), and zirconia balls (ball diameter: 3 mm) was placed in a ceramic pot so as to have a volume filling rate of 30%, and dispersed for 8 hours at a rotational speed of 220 rpm using a desktop pot mill.

In the obtained liquid developer, Dv (50) of the toner particles was 2.4 μm, and Dv (50) / Dn (50) was 1.08.
The same as above except that magenta pigment: pigment red 122, yellow pigment: pigment yellow 180, black pigment: carbon black (Printex L, manufactured by Degussa) was used instead of cyan pigment. Thus, a magenta liquid developer, a yellow liquid developer, and a black liquid developer were produced.

(Examples 2 to 8)
A liquid developer corresponding to each color was produced in the same manner as in Example 1 except that the resin material, amine compound, and type and content of the insulating liquid used were configured as shown in Table 1. .
Example 9
First, styrene-acrylic copolymer R1: 45 parts by weight, cyan pigment as a colorant (Dainipei Seika Co., Ltd., Pigment Blue 15: 3): 50 parts by weight, and FEKA-4300 (Ciba -Specialty Chemicals Co., Ltd. product, the amine value: 56.0 mgKOH / g): The mixture with 5 weight part was prepared. These components were mixed using a 20 L type Henschel mixer to obtain a raw material for a colorant master.

Next, this raw material was kneaded using a biaxial kneading extruder heated to 120 ° C. to obtain a kneaded product. Next, the kneaded product extruded from the extrusion port of the biaxial kneading extruder was cooled.
The kneaded product cooled as described above was coarsely pulverized to obtain a powder having an average particle size of 1.0 mm or less to obtain a colorant master (pulverized product). A hammer mill was used for coarse pulverization of the kneaded product.
Next, the pulverized product thus obtained: 50 parts by weight and acrylic resin R1: 50 parts by weight were kneaded using a biaxial kneading extruder heated to 120 ° C., and after cooling, coarsely pulverized. A powdery colored raw material having an average particle size of 1.0 mm or less was obtained.

Next, the coloring material obtained by the above method: 40 parts by weight, soybean oil transesterification liquid produced by transesterification reaction between soybean oil and methanol (viscosity 5.1 mPa · s, manufactured by Nisshin Oilio Co., Ltd., commercial product) Name “soybean oil fatty acid methyl”): 60 parts by weight, high oleic rapeseed oil (manufactured by Nisshin Oilio Co., Ltd., trade name “high oleic rapeseed oil”): 90 parts by weight, dispersant (Solsperse 13940, manufactured by Nihon Lubrizol): 2.0 Part by weight, and aluminum stearate as a charge control agent (Nippon Yushi Co., Ltd.): 3.0 parts by weight are placed in a ceramic pot (internal volume 600 ml), and zirconia balls (ball diameter: 1 mm) are filled in a volume of 30. % In a ceramic pot, and pulverized in a desktop pot mill at a rotational speed of 220 rpm for 48 hours. To produce a body developer.
In the obtained liquid developer, Dv (50) of the toner particles was 7.9 μm, and Dv (50) / Dn (50) was 1.25.

(Comparative Examples 1-4)
A liquid developer corresponding to each color was produced in the same manner as in Example 1 except that the resin material, amine compound, and type and content of the insulating liquid used were configured as shown in Table 1. .
In each of the above Examples and Comparative Examples, the type of resin used, the type of amine compound, the amine value, the acid value, the type of skeleton constituting the main chain, -NHR, -NR'R contained in the chemical structure Table 1 shows the presence / absence, content, type of insulating liquid, content, etc. of the functional group represented by ″ (where R, R ′, and R ″ are alkyl groups). In Table 1, the amine value of each amine compound is a value measured according to JIS K7237 “Testing method for total amine value of amine-based curing agent of epoxy resin” (1995), and the acid value of each amine compound. Indicates values measured according to JIS K0070. Further, the liquid developer obtained in each example was filtered, and the cross section of the obtained toner particles was subjected to KFM measurement using a scanning probe microscope SPM-9600 (manufactured by Shimadzu Corporation). Thereby, the distribution state of the amine compound in the toner particles can be known. As a result of such KFM measurement, in the toner particles constituting each liquid developer of Examples 1 to 8, various amine compounds are unevenly distributed in the vicinity of the surface of the toner particles. Presence of amine compound was not recognized. On the other hand, in the toner particles constituting the liquid developer of Example 9, it was confirmed that the amine compound was dispersed throughout the toner particles. Further, in the toner particles contained in each liquid developer of Examples 1, 2, 7, and 8, acrylic resin (acrylic resin R1 or acrylic resin R2) and various amine compounds are phase-separated to form a sea-island structure. It was confirmed that was formed.

  In Table 1, styrene-acrylic copolymer R1 as an acrylic resin is “R1”, styrene-acrylic copolymer R2 (acid value: 12.0 KOHmg / g, weight average molecular weight Mw: 82,000, glass Transition temperature Tg: 103 ° C., softening temperature Tf: 125 ° C. is “R2”, EFKA-6220 (Ciba Specialty Chemicals Co., Ltd., amine value: 35.0 mgKOH / g, acid value: 22.0 mgKOH / g) “a”, Ajisper PB821 (Ajinomoto Fine Techno Co., Ltd., amine value: 10.0 mgKOH / g, acid value: 17.5 mgKOH / g) “b”, Disperbyk-2000 (Bic Chemie) Manufactured by Co., Ltd., amine value: 4.0 mgKOH / g) “c”, Disperbyk-116 (manufactured by Big Chemie Co., Ltd., amine value: 6) 0.0 mgKOH / g) “d”, EFKA-4046 (Ciba Specialty Chemicals Co., Ltd., amine value: 18.0 mgKOH / g) “e”, FEKA-4300 (Ciba Specialty Chemicals Co., Ltd.) ), Amine value: 56.0 mgKOH / g) is “f”, Disperbyk-2001 (manufactured by Big Chemie, amine value: 29.0 mgKOH / g, acid value: 19.0 mgKOH / g) is “g” Disperbyk-130 (produced by Big Chemie Co., Ltd., amine value: 190.0 mgKOH / g) is "h", soybean oil transesterification solution produced by transesterification of soybean oil and methanol (Nisshin Oilio Co., Ltd.) Product name “soybean oil fatty acid methyl”) “j”, high oleic rapeseed oil (Nisshin Oilio Co., Ltd. Rapeseed oil ”)“ k ”, Cosmo White P-60 (viscosity 15 mPa · s, manufactured by Cosmo Oil Lubricants)“ l ”, Dyna Fresia W-8 (viscosity 14 mPa · s, manufactured by Idemitsu Kosan Co., Ltd.)“ m ” ”, Methyl laurate (Lion Co., Ltd. Pastel M-12) is indicated by“ n ”.

［２］評価
上記のようにして得られた各液体現像剤について、以下のような評価を行った。
［２．１］正帯電の帯電特性
各実施例および各比較例で得られた液体現像剤について、マイクロチック・ニチオン社製の「顕微鏡式レーザーゼータ電位計」ＺＣ−２０００を用いて電位差を測定し、以下の５段階の基準に従い評価した。
測定は、液体現像剤を希釈溶媒で希釈して、１０ｍｍの透明セルに入れ、電極間９ｍｍで３００Ｖの電圧をかけると同時に顕微鏡でセル内の粒子の移動速度を観察することで、移動速度を算出して、その値からゼータ電位を求めることにより行った。

[2] Evaluation Each liquid developer obtained as described above was evaluated as follows.
[2.1] Charging characteristics of positive charge For the liquid developer obtained in each example and each comparative example, the potential difference was measured using a “microscopic laser zeta electrometer” ZC-2000 manufactured by Microtic Nichion. The evaluation was made according to the following five criteria.
The measurement is performed by diluting the liquid developer with a diluting solvent, putting it in a 10 mm transparent cell, applying a voltage of 300 V at 9 mm between the electrodes, and simultaneously observing the moving speed of the particles in the cell with a microscope. The calculation was performed by calculating the zeta potential from the value.

A: The potential difference is +100 mV or more (very good).
B: Potential difference is +85 mV or more and less than +100 mV (good).
C: The potential difference is +70 mV or more and less than +85 mV (normal).
D: The potential difference is +50 mV or more and less than +70 mV (somewhat bad).
E: Potential difference is less than +50 mV (very bad).

[2.2] Development efficiency Monochromatic liquid developer using the liquid developer obtained in each of the examples and comparative examples on the developing roller of the image forming apparatus using an image forming apparatus as shown in FIG. A layer was formed. Next, the developer roller potential is set to 300 V, the surface of the photosensitive member is uniformly charged at 500 V, and the toner particles on the developing roller after the liquid developer layer passes between the photosensitive member and the developing roller; The toner particles on the photoreceptor were collected with a tape. Each tape used for sampling was affixed on a recording paper, and the concentration of each toner particle was measured. After the measurement, the value obtained by dividing the concentration of toner particles collected on the photoreceptor by the sum of the concentration of toner particles collected on the photoreceptor and the concentration of toner particles collected on the developing roller is multiplied by 100. Value X (development efficiency) was determined and evaluated according to the following five-step criteria.

A: X ≧ 95 (particularly excellent)
B: 90 ≦ X <95 (excellent)
C: 85 ≦ X <90 (normal)
D: 80 ≦ X <85 (somewhat bad)
E: X <80 (very bad)

[2.3] Transfer Efficiency Monochromatic liquid developer using the liquid developer obtained in each of the embodiments and comparative examples on the developing roller of the image forming apparatus using an image forming apparatus as shown in FIG. A layer was formed. Next, the potential of the developing roller was set to 300V, and the surface of the photoconductor was uniformly charged at 500V to form a solid toner image on the photoconductor. After the toner image passed between the photoreceptor and the intermediate transfer portion, the toner particles on the photoreceptor and the toner particles on the intermediate transfer portion were collected with a tape. Each tape used for sampling was affixed on a recording paper, and the concentration of each toner particle was measured. After the measurement, a value obtained by dividing the concentration of the toner particles collected on the intermediate transfer portion by the sum of the concentration of the toner particles collected on the intermediate transfer portion and the concentration of the toner particles collected on the photoreceptor is 100. The value Y (transfer efficiency) multiplied by is determined and evaluated according to the following five-step criteria.

A: Y ≧ 95 (particularly excellent)
B: 90 ≦ Y <95 (excellent)
C: 85 ≦ Y <90 (normal)
D: 80 ≦ Y <85 (somewhat bad)
E: Y <80 (bad)

[2.4] Dispersion stability The liquid developers obtained in the respective Examples and Comparative Examples were allowed to stand for 6 months in an environment at a temperature of 15 to 25 ° C. Thereafter, the state of the toner in the liquid developer was visually confirmed and evaluated according to the following five-step criteria.
A: No toner particle floating or coagulation sedimentation is observed.
B: Floating and coagulation sedimentation of toner particles are hardly observed.
C: Slight floating or coagulation sedimentation of toner particles is observed, but as a liquid developer
There is no problem.
D: Floating or coagulation sedimentation of toner particles is clearly observed.
E: Suspension and coagulation sedimentation of toner particles are remarkably observed.

[2.5] Fixing Strength Using an image forming apparatus as shown in FIG. 2, an image of a predetermined pattern with a liquid developer obtained in each of the examples and the comparative examples was recorded on a recording paper (manufactured by Seiko Epson Corporation, It was formed on fine paper LPCPPA4). Thereafter, thermal fixing was performed using a fixing device as shown in FIG. 5 at a set temperature of the heat fixing roller of 100 ° C.
Then, after confirming the non-offset area, the fixed image on the recording paper is erased twice (rubber eraser “LION 261-11” manufactured by Lion Business Machine Co., Ltd.) twice with a pressing load of 1.2 kgf, and the remaining ratio of image density Was measured by “X-Rite model 404” manufactured by X-Rite Inc, and evaluated according to the following five-step criteria.

A: Image density residual ratio is 95% or more (very good).
B: Image density remaining rate is 90% or more and less than 95% (good).
C: Image density remaining rate is 80% or more and less than 90% (normal).
D: Image density residual ratio is 70% or more and less than 80% (slightly bad).
E: Image density residual ratio is less than 70% (very bad).

表２から明らかなように、各実施例の液体現像剤は、正帯電の帯電特性に優れ、現像効率、転写効率に優れたものであり、得られるトナー画像は、均一な画像濃度を有するものであった。これに対し、比較例の液体現像剤では、満足な結果が得られなかった。

As is apparent from Table 2, the liquid developer of each example is excellent in positive charge characteristics, excellent in development efficiency and transfer efficiency, and the obtained toner image has a uniform image density. Met. On the other hand, satisfactory results were not obtained with the liquid developer of the comparative example.

1 is a schematic diagram illustrating an example of an image forming apparatus to which a liquid developer as a colored fine particle dispersion of the present invention is applied. FIG. 2 is an enlarged view of a part of the image forming apparatus shown in FIG. 1. FIG. 6 is a schematic diagram illustrating a state of toner particles in a liquid developer layer on a developing roller. FIG. 2 is a cross-sectional view illustrating an example of a fixing device applied to the image forming apparatus illustrated in FIG. 1.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Toner particle 1000 ... Image forming apparatus 10Y, 10M, 10C, 10K ... Photoconductor 11Y ... Charging roller 12Y ... Exposure unit 13M, 13Y ... Photoconductor squeeze roller 14M, 14Y ... Cleaning blade 15M, 15Y ... Developer collection part 16Y Destaticizing unit 17Y Photoconductor cleaning blade 18Y Developer collecting unit 20Y, 20M, 20C, 20K Developing roller 201Y Liquid developer layer 21Y Developing roller cleaning blade 22Y Developer compressing roller 23Y Cleaning blades 30Y, 30M 30C, 30K ... developing unit 31Y ... liquid developer storage unit 32Y ... application roller 33Y ... regulator blade 34Y ... developer stirring roller 40 ... intermediate transfer unit 41 ... belt drive roller 42 ... tension roller 46 ... medium Transfer unit cleaning blade 47 ... Developer recovery unit 51Y, 51M, 51C, 51K ... Primary transfer backup roller 52Y, 52M, 52C, 52K ... Intermediate transfer unit squeeze device 53Y ... Intermediate transfer unit squeeze roller 54Y ... Intermediate transfer unit squeeze backup Roller 55Y ... Intermediate transfer unit squeeze cleaning blade 60 ... Secondary transfer unit 61 ... Secondary transfer roller 62 ... Cleaning blade 63 ... Developer recovery unit 70Y ... Conveyance path 80Y, 80M, 80C, 80K ... Liquid developer supply unit 81Y ... Collected liquid developer reservoir 82Y ... Supply liquid developer reservoir 83Y, 84Y ... Conveying means 85Y ... Pump 86Y ... Filter 100Y ... Developer unit 101Y ... Photoconductor squeeze device F40 ... Fixing unit (fixing device) F1 ... Heat fixing roller La (Heating roller) F1a ... Column-shaped halogen lamp F1b ... Roller base material F1c ... Elastic body F12 ... Removal blade F2 ... Pressure roller F2a ... Rotating shaft F2b ... Roller base material F2c ... Elastic body F3 ... Heat-resistant belt F4 ... Belt stretch Member F4a ... Projection wall F4f ... Recess F5 ... Recording medium F5a ... Toner image F6 ... Cleaning member F7 ... Frame F9 ... Spring

Claims (11)

A colorant;
Acrylic resin,
An amine compound having an amine value of 1 to 100 mgKOH / g,
Colored resin fine particles, wherein the amine compound content is 0.9 to 9.1 wt%.   The colored resin fine particles according to claim 1, wherein the amine compound has a main chain having a polyester skeleton.   3. The colored resin fine particles according to claim 1, wherein the particle size distribution Dv / Dn is 1.00 to 1.12.   4. The amine compound according to claim 1, wherein the amine compound is an aliphatic amine having a functional group represented by —NHR and / or —NR′R ″ (wherein R, R ′, and R ″ are alkyl groups). The colored resin fine particles according to any one of the above.   The colored resin fine particles are obtained by coalescing the dispersoid in an emulsion in which a dispersoid containing the colorant, the acrylic resin, the amine compound, and an organic solvent is dispersed in an aqueous dispersion medium. The colored resin fine particles according to any one of claims 1 to 4, wherein the colored resin fine particles are produced by the method described above.   The colored resin fine particles according to claim 1, wherein the colored resin fine particles are toner particles. Having colored resin fine particles and insulating liquid;
The colored resin fine particles include a colorant, an acrylic resin, and a compound having an amine value of 1 to 100 mgKOH / g.
A colored resin fine particle dispersion having a content of the amine compound of 0.9 to 9.1 wt%.   The colored resin fine particle dispersion according to claim 7, wherein the colored resin fine particle dispersion is a liquid developer (liquid toner). A dispersion preparation step of preparing a dispersion in which a dispersoid containing a colorant, an acrylic resin, an amine compound having an amine value of 1 to 100 mgKOH / g, and an organic solvent is dispersed in an aqueous dispersion medium;
Coalescing a plurality of the dispersoids to obtain coalesced particles; and
Removing the organic solvent contained in the coalesced particles, and obtaining a colored resin fine particle,
The method for producing colored resin fine particles, wherein the colored resin fine particles obtained in the solvent removal step comprise 0.9 to 9.1 wt% of the amine compound.   The dispersion is obtained by adding an aqueous liquid to a solution containing the colorant, the acrylic resin, the amine compound, and the organic solvent. The method for producing colored resin fine particles according to claim 9, wherein a dispersoid containing the acrylic resin, the amine compound, and the organic solvent is dispersed in an aqueous dispersion medium. A dispersion preparation step of preparing a dispersion in which a dispersoid containing a colorant, an acrylic resin, an amine compound having an amine value of 1 to 100 mgKOH / g, and an organic solvent is dispersed in an aqueous dispersion medium;
Coalescing a plurality of the dispersoids to obtain coalesced particles; and
Removing the organic solvent contained in the coalesced particles to obtain a colored resin fine particle, and a dispersion step of dispersing the colored resin fine particle in an insulating liquid,
The method for producing a colored resin fine particle dispersion, wherein the colored resin fine particles obtained in the solvent removal step contain 0.9 to 9.1 wt% of the amine compound.

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