JP2021193428A - Toner for electrophotography, image post-processing method and image post-processing device, and image forming method and image forming apparatus - Google Patents

Abstract

To provide, according to the present invention, control means for image glossiness that has a high degree of freedom in selection of an image forming method and an image forming apparatus applied in a toner for electrophotography.SOLUTION: The present invention relates to a toner for electrophotography including a binder resin, a colorant, and a heat-sensitive material whose light scattering properties are changed by at least one of a heating temperature and a cooling rate.SELECTED DRAWING: None

Description

The present invention relates to an electrophotographic toner, an image post-processing method and an image post-processing apparatus, and an image forming method and an image forming apparatus.

In recent years, the types of recording media on which images are formed have diversified. For example, since the surface shapes of high-quality paper and coated paper are different, the glossiness is different. Further, when a toner image is formed on a recording medium, there is a difference between the gloss of the portion where the image is formed (image portion) and the gloss of the background portion (non-image portion) of the recording medium on which the image is not formed. If it is large, the user may feel uncomfortable.

In Patent Document 1, in order to control the glossiness of the toner image, the selection between the case where the image is glossy and the case where the image is not glossy is switched by changing the fixing temperature of the image. The fixing device is disclosed.

Further, Patent Document 2 discloses an image post-processing method in which a fixing toner image on a recording medium is heated by using a non-contact heating means to reduce the glossiness to control the glossiness.

Japanese Unexamined Patent Publication No. 2007-072022 Japanese Unexamined Patent Publication No. 2019-101242

However, when the image glossiness is controlled by the fixing temperature by using the fixing device according to Patent Document 1, the amount of heat given to the toner image becomes insufficient when the gloss of the toner image is lowered, and the image is transferred to the recording medium. There is a problem that the fixing strength of the toner image is insufficient.

Further, although the image post-processing method according to Patent Document 2 can solve the above-mentioned problem in the technique of Patent Document 1, since the heating means is limited to the non-contact heating means, even when the contact heating means is used. There is a demand for technology that enables control of image gloss.

Therefore, as a result of diligent studies, the present inventors have found that the image glossiness can be controlled by the composition of the electrophotographic toner regardless of the heating means. Therefore, an object of the present invention is to provide a control means for image glossiness, which has a high degree of freedom in selecting an applied image forming method and an image forming apparatus in an electrophotographic toner.

The above-mentioned problems of the present invention can be solved by the following means.

An electrophotographic toner containing a binder resin, a colorant, and a heat-sensitive material whose light scattering property changes depending on at least one of a heating temperature and a cooling rate.

INDUSTRIAL APPLICABILITY According to the present invention, it is possible to provide a means for controlling image glossiness, which has a high degree of freedom in selecting an applied image forming method and an image forming apparatus in an electrophotographic toner.

It is a schematic diagram which shows an example of the heat treatment part 100 in the image post-processing apparatus which concerns on one Embodiment of this invention. It is a schematic diagram which shows another example of the heat treatment part 100 in the image post-processing apparatus which concerns on one Embodiment of this invention. It is a schematic diagram which shows the schematic structure of the image forming apparatus which concerns on one Embodiment of this invention.

In the present specification, "X to Y" indicating a range means "X or more and Y or less". Unless otherwise specified, the operation, physical properties, etc. are measured under the conditions of room temperature (20 to 25 ° C.) / relative humidity of 40 to 50% RH.

Further, in the present specification, the (co) polymer is a general term including a copolymer and a homopolymer.

And, in this specification, "(meth) acrylate" is a general term of acrylate and methacrylate. Similarly, compounds containing (meta) such as (meth) acrylic acid are a general term for compounds having "meta" in the name and compounds having no "meta".

Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings as necessary. In the description of the drawings, the same elements are designated by the same reference numerals, and duplicate description will be omitted. In addition, the dimensional ratios in the drawings are exaggerated for convenience of explanation and may differ from the actual ratios.

<Toner for electrophotographic>
One embodiment of the present invention relates to an electrophotographic toner comprising a binder resin, a colorant, and a heat-sensitive material whose light scattering property changes depending on at least one of a heating temperature and a cooling rate.

The toner for electrophotographic according to the embodiment of the present invention is preferably a toner matrix particle or an aggregate of toner particles. Here, the toner particles are those in which an external additive is added to the toner matrix particles, and the toner matrix particles can be used as they are as the toner particles.

The present inventors presume the mechanism by which the problem is solved by the above configuration as follows.

The electrophotographic toner according to the present invention includes a heat-sensitive material whose light scattering property changes depending on at least one of a heating temperature and a cooling rate. The electrophotographic toner controls the glossiness of the toner image, that is, the image glossiness by changing the light scattering property of the heat-sensitive material itself contained therein. Therefore, unlike the technique of controlling the image glossiness by changing the surface shape of the toner image as in Patent Document 2, the image glossiness can be controlled regardless of the surface shape of the toner image. Therefore, the electrophotographic toner has a good image not only when the non-contact heating means is used as the heating means but also when the contact heating means which can affect the surface shape of the toner image is used. Allows control of gloss.

The above mechanism is based on speculation, and its correctness does not affect the technical scope of the present invention.

[Heat-sensitive material]
The toner matrix particles according to the embodiment of the present invention include a heat-sensitive material whose light scattering property changes depending on at least one of a heating temperature and a cooling rate.

The heat-sensitive material acts to control the glossiness of the toner image, that is, the image glossiness.

In the present specification, when it is confirmed visually that the degree of white turbidity of the appearance changes when at least one of the heating temperature and the cooling rate is changed for the material, the material is referred to as the heating temperature. And it is judged that it is a heat-sensitive material whose light scattering property changes depending on at least one of the cooling rates. The judgment is preferably made using a material having a thickness of 15 μm.

The heat-sensitive material is preferably a material having a thickness of 15 μm whose haze value changes by 30% or more by changing at least one of the heating temperature and the cooling rate (upper limit: haze value 100%).

Further, it is preferable that the haze value changes by 30% or more in each case when the heating temperature and the cooling rate of the heat-sensitive material having a thickness of 15 μm are changed (upper limit: haze value 100%).

Then, it is preferable to confirm that the heat-sensitive material having a thickness of 15 μm has a haze value of 10% or less when at least one of the heating temperature and the cooling rate is changed (lower limit 0%: haze value). Further, when the heating temperature and the cooling rate of the heat-sensitive material having a thickness of 15 μm are changed, it is preferable to confirm that the haze value is 10% or less in each case (lower limit: haze value). 0%).

Here, the heat-sensitive material having a thickness of 15 μm may be in the form of a layer or a film, and may be arranged on a transparent plate, sandwiched between transparent plates, or enclosed in a transparent container. It may be. When a transparent plate or a transparent container is used, it is preferable that the haze value of the transparent plate or the transparent container does not substantially change depending on the heating temperature and the cooling rate.

The haze value can be measured according to JIS K 7136: 2000 using a haze meter (model NDH 2000, manufactured by Nippon Denshoku Co., Ltd.). As an example, in the case where the heat-sensitive material having a thickness of 15 μm is a film, the details of the evaluation method will be described in Examples.

Further, the change in the haze value as described above preferably occurs in the range of 25 to 200 ° C., more preferably in the range of 25 to 150 ° C., and occurs in the range of 25 to 120 ° C. Is even more preferable.

The heat-sensitive material is not particularly limited as long as it is a material whose light scattering property changes depending on at least one of the heating temperature and the cooling rate, and a known material can be used.

The heat-sensitive material preferably contains a liquid crystal compound from the viewpoint that the image glossiness can be easily controlled, the control range is wide, and a reversible change is possible. The liquid crystal compound is a compound showing a liquid crystal phase, and generally, a solid phase such as a crystalline phase or an amorphous phase, or a plurality of phases such as one or more liquid crystal phases and an isotropic phase, depending on the temperature. Is shown. In general, even the same liquid crystal compound has different light scattering properties in these different phases. Further, depending on the cooling rate from the liquid crystal phase or the isotropic phase, it may be possible to form a solid phase that retains the characteristics of these phases, and if it is possible to control the degree to which the characteristics of these phases are retained. There is. As described above, the liquid crystal compound has a function of changing its light scattering property by undergoing a phase transition depending on the temperature.

The liquid crystal compound is not particularly limited, and a known liquid crystal compound can be used. The liquid crystal compound may be a low molecular weight liquid crystal compound or a high molecular weight liquid crystal compound. Among these, from the viewpoint that it is easy to form a solid phase that retains the characteristics of the liquid crystal phase and the isotropic phase, it is easy to control to the extent that the characteristics of these phases are retained, and the stability of the characteristics is high. , It is preferably a polymer liquid crystal compound. Examples of the polymer liquid crystal compound include a main chain type polymer liquid crystal compound which is a polymer liquid crystal compound having a mesogen group in the main chain, a side chain type polymer liquid crystal compound having a mesogen group in the side chain, and a mesogen group. It may be either a composite polymer liquid crystal compound having a main chain and a side chain. Among these, from the above viewpoint, as the polymer liquid crystal compound, a main chain type polymer liquid crystal compound or a side chain type polymer liquid crystal compound is more preferable, and a side chain type polymer liquid crystal compound is further preferable. .. For example, the polymer liquid crystal compounds described in JP-A-7-304265, JP-A-10-62739 and the like can be used.

As the low molecular weight liquid crystal compound, it is preferable that the molecular weight calculated from the total atomic weight is less than 1,000.

The polymer liquid crystal compound preferably has a weight average molecular weight of 1,000 or more, more preferably 5,000 or more, and even more preferably 10,000 or more. The weight average molecular weight of the polymer liquid crystal compound is preferably 1,000,000 or less, more preferably 500,000 or less, still more preferably 200,000 or less, and 100,000 or less. The following is particularly preferable. The weight average molecular weight of the polymer liquid crystal compound can be obtained from the molecular weight distribution measured by GPC (gel permeation chromatography) using polystyrene as a standard substance.

More specifically, the sample was added to tetrahydrofuran (THF) to a concentration of 1 mg / mL, dispersed at room temperature for 5 minutes using an ultrasonic disperser, and then treated with a membrane filter having a pore size of 0.2 μm. To prepare the sample solution. Using a GPC device HLC-8120GPC (manufactured by Tosoh Corporation) and a column "TSKguardcolum + TSKgel SuperHZM-M3 series" (manufactured by Tosoh Corporation), THF was used as a carrier solvent at a flow rate of 0.2 mL / min while maintaining the column temperature at 40 ° C. Shed with. 10 μL of the prepared sample solution is injected into the GPC device together with the carrier solvent, and the sample is detected using a refractive index detector (RI detector). Then, the molecular weight distribution of the sample is calculated using a calibration curve measured using 10 points of monodisperse polystyrene standard particles.

The side-chain type polymer liquid crystal compound is not particularly limited, and a known side-chain type polymer liquid crystal compound can be used. Among these, a (co) polymer containing a structure represented by the following general formula (1) is preferable.

In the above general formula (1), the organic group of R may be a substituted or unsubstituted alkyl group, a substituted or unsubstituted alkoxy group, a halogen group, a nitro group, a cyano group, or a hydrogen atom. preferable. When the organic group of R has a substituent, the substituent is preferably an unsubstituted alkyl group, an unsubstituted alkoxy group, a halogen group, a nitro group, or a cyano group. Among these, the organic group of R is more preferably an unsubstituted linear alkyl group, an unsubstituted branched alkyl group, an unsubstituted cycloalkyl group, or a cyano group, and an unsubstituted cycloalkyl group, A cyano group is more preferred.

In the above general formula (1), n in A is preferably an integer of 1 or more and 30 or less, more preferably an integer of 2 or more and 12 or less, and further preferably an integer of 3 or more and 6 or less. preferable.

In the copolymer containing the structure represented by the general formula (1), the structural unit having a mesogen group represented by the following formula (hereinafter, also simply referred to as “constituent unit having a mesogen group”) is a single substance. Although it may be used in combination of two or more, it is preferable to use it alone.

The copolymer containing the structure represented by the general formula (1) may contain a structural unit other than the structural unit having a mesogen group.

The compound constituting the other structural unit is not particularly limited, and may be any known compound capable of forming the copolymer by copolymerization or copolymerization. For example, a compound having a vinyl group or a (meth) acryloyl group can be mentioned, preferably a compound having a (meth) acryloyloxy group or a (meth) acryloylamide group, and a compound having a (meth) acryloyloxy group. Is even more preferable. More specifically, the compound which can constitute another structural unit is not particularly limited, and for example, (meth) alkyl acrylate and its derivative, styrene and its derivative, vinyl acetate, (meth) acrylonitrile, vinyl chloride, and the like. Vinylidene chloride, vinylpyrrolidone, 1-hexene, 1-octene, (meth) acrylic acid, ω-carboxy-polycaprolactone-mono (meth) acrylate, vinyl sulfonate, hydroxyethyl (meth) acrylate, hydroxypropyl (meth) acrylate , 2- (meth) acryloxyethyl acid phosphate, 2-hydroxy-3-phenoxypropyl (meth) acrylate, 2- (meth) acryloxyethyl succinate, mono (meth) phthalate, 2- (meth) Acryloxyethyl (2-hydroxyethyl) phthalate, 4- (meth) acryloxyalkyloxybenzoic acid, glyceryl (meth) acrylate, hydroxy group-substituted styrene, meta (acrylic) amide, N, N-dimethylaminoethyl (meth) Examples thereof include acrylate, N, N-diethylaminoethyl (meth) acrylate, glycidyl (meth) acrylate, 2-propen-1-ol, 5-hexene-1-ol and the like. Among these, alkyl (meth) acrylate or a derivative thereof is preferable, and methyl (meth) acrylate, ethyl (meth) acrylate, n-butyl (meth) acrylate, isobutyl (meth) acrylate, (meth) acrylic. T-butyl acid, cyclohexyl (meth) acrylate, -2-ethylhexyl (meth) acrylate are more preferred, and n-butyl (meth) acrylate is even more preferred. These compounds may be used alone or in combination of two or more, but are preferably used alone.

The copolymer having a structural unit having a mesogen group and another structural unit may be any of a block polymer, an alternating copolymer and a random polymer with respect to these structural units.

The ratio of the other constituent units to the copolymer having the constituent units having a mesogen group and the other constituent units is not particularly limited. The content ratio of the other structural units as the monomer unit is preferably 0.1 mol% or more, more preferably 0.5 mol% or more, and 1 mol% with respect to all the structural units. The above is more preferable. Within these ranges, the copolymer can be obtained more easily. The ratio of the other structural units as the monomer unit is preferably 70 mol% or less, more preferably 50 mol% or less, and 20 mol% or less with respect to all the structural units. Is even more preferable. Within this range, the stability of the liquid crystal phase is further improved.

Specific examples of preferable polymer liquid crystal compounds are shown below. In the following equation, n represents an integer of 1 or more, respectively. Among these, compound (I-1) and compound (II-4) are particularly preferable.

In the present specification, the ring structure represented by “H” inside the cyclohexyl group and the cyclohexylene group is an unsubstituted cyclohexyl group and an unsubstituted cyclohexylene group, respectively. Represents.

When the liquid crystal compound has a glass transition point, it is preferable that the liquid crystal compound expresses a liquid crystal phase at a temperature equal to or higher than the glass transition point of the liquid crystal compound.

The glass transition point (Tg) of the liquid crystal compound is not particularly limited, but is preferably 25 ° C. or higher, and more preferably 25 ° C. or higher. The glass transition point (Tg) can be measured by, for example, a DSC (differential calorimetry).

As the liquid crystal compound, a synthetic product or a commercially available product may be used. The method for synthesizing the polymer liquid crystal compound is not particularly limited, and a known method can be used. For example, the synthesis method described in JP-A No. 10-62739 can be used.

The heat-sensitive material is preferably a mixture containing a high molecular weight compound and a low molecular weight compound. The low molecular weight compound has a function of changing the light scattering property as a mixture thereof. The reason for this is presumed as follows. The low molecular weight compound present in the high molecular weight compound in a finely dispersed manner melts depending on the temperature. At this time, the low molecular weight compound fills the vacancies existing between the low molecular weight compound and the high molecular weight compound, and the light scattering property of the mixture as a whole changes. Further, at a higher temperature, the low molecular weight compound is in a molten state, and the polymer compound is also in a molten state (in the case of a polymer liquid crystal compound, it is an isotropic phase). Again, there is a further change in the light scattering property of the mixture as a whole. In addition, the mixture that has undergone such a state may be able to form a solid phase that retains the characteristics of these phases, depending on the cooling rate, and the degree to which the characteristics of these phases are retained can also be controlled. In some cases.

The polymer compound is not particularly limited in the mixture containing the polymer compound and the low molecular weight compound, but for example, the above-mentioned polymer liquid crystal compound, polyvinyl chloride resin, polyvinyl acetate resin, vinyl chloride-vinyl acetate. Examples thereof include a copolymer, a polyester resin, a polyvinyl butyral resin, a polyurethane resin, and a polyamide resin. Among these, the above-mentioned high molecular weight liquid crystal compound is preferable. That is, it is particularly preferable that the heat-sensitive material contains a low-molecular-weight compound in addition to the above-mentioned high-molecular-weight liquid crystal compound. Further, the heat-sensitive material may be a mixture containing the above-mentioned polymer liquid crystal compound, another polymer compound, and a low-molecular compound. By using a mixture containing a high molecular weight liquid crystal compound and a low molecular weight compound as the heat sensitive material, the action of the high molecular weight liquid crystal compound and the action of the low molecular weight compound are combined, and the control range of the image glossiness is further expanded. However, its stability is also enhanced.

In the mixture containing the high molecular weight compound and the low molecular weight compound, the low molecular weight compound may be a liquid crystal compound or a non-liquid crystal compound, but is preferably a non-liquid crystal compound.

In the mixture containing the high molecular weight compound and the low molecular weight compound, the melting point of the low molecular weight compound is not particularly limited, but is preferably 30 ° C. or higher, more preferably 50 ° C. or higher, and more preferably 60 ° C. or higher. Is even more preferable. Within this range, the control range of image glossiness is further expanded, and its stability is further enhanced. The melting point of the low molecular weight compound is not particularly limited, but is preferably 200 ° C. or lower, more preferably 150 ° C. or lower, and even more preferably 90 ° C. or lower. Within this range, the control range of the image glossiness is further expanded, and the control becomes easier. As a preferred example, the melting point of the low molecular weight compound is 60 ° C. or higher and 90 ° C. or lower.

In the mixture containing the high molecular weight compound and the low molecular weight compound, the low molecular weight compound is not particularly limited, but a long chain compound having 10 or more carbon atoms is preferable. The number of carbon atoms is preferably 10 to 60, more preferably 10 to 38, and even more preferably 10 to 30. Also, at least one of oxygen, nitrogen, sulfur and halogen in the molecule, such as -OH, -COOH, -CONH-, -COOR, -NH-, -NH ₂ , -S-, -S-S-, It is preferably a compound containing —O—, halogen and the like. For example, alkanol; alkanediol; halogen alkanol or halogen alkanediol; alkylamine; alkane; alkene; alkyne; halogen alkane; halogen alkene; halogen alkyne; cycloalkane; cycloalkene; cycloalkyne; saturated or unsaturated mono or dicarboxylic acid or These esters, amides or ammonium salts; saturated or unsaturated halogen fatty acids or their esters, amides or ammonium salts; allylcarboxylic acids or their esters, amides or ammonium salts; halogen allylcarboxylic acids or their esters, amides or ammoniums. Salts; thioalcohol; thiocarboxylic acids or esters thereof, amines or ammonium salts; carboxylic acid esters of thioalcohol and the like. The alcohol group portion in the ester may be saturated or not saturated, or may be halogen-substituted. Specifically, for example, myristic acid, pentadecic acid, palmitic acid, stearic acid, behenic acid, nonadecanic acid, araginic acid, lignoseric acid, montanic acid, melicic acid, methyl stearate, tetradecyl stearate, octadecyl stearate, laurin. Examples thereof include octadecyl acid acid, tetradecyl palmitate, dodecyl behenate, and ethers or thioethers described in “Table 3” of paragraph “0018” of JP-A-7-304265. Among these, saturated or unsaturated mono or dicarboxylic acid or an ester thereof is preferable, and saturated or unsaturated mono or dicarboxylic acid is more preferable, and saturated monocarboxylic acid is preferable from the viewpoint of the control range of image gloss. It is more preferably an acid, and particularly preferably a behenic acid. These compounds may be used alone or in combination of two or more, but are preferably used alone.

In the mixture containing the high molecular weight liquid crystal compound and the low molecular weight compound, the ratio of these contents is not particularly limited, but from the viewpoint of the control range of the image glossiness, the high molecular weight liquid crystal compound: low in terms of mass ratio. The molecular compound is preferably 0.5 to 20: 1. Further, the ratio of these contents is more preferably 1 to 10: 1 and further preferably 1 to 5: 1 in terms of mass ratio.

Low molecular weight compounds and other high molecular weight compounds may also be synthetic products or commercially available products.

The heat-sensitive material may be used alone or in combination of two or more.

The content of the heat-sensitive material is not particularly limited, but is preferably 1% by mass or more, more preferably 2% by mass or more, and 3% by mass with respect to the total mass (100% by mass) of the toner particles. The above is more preferable. Within these ranges, the control range of image glossiness can be further expanded. The content of the heat-sensitive material is preferably 30% by mass or less, more preferably 20% by mass or less, and 10% by mass or less with respect to the total mass (100% by mass) of the toner particles. Is even more preferable. Within these ranges, the influence on the fixing property, heat resistance, etc. of the electrophotographic toner itself is smaller, and the toner exhibits better characteristics as an electrophotographic toner.

When the heat-sensitive material contains a liquid crystal compound, the content of the liquid crystal compound is not particularly limited, but is preferably 1% by mass or more with respect to the total mass (100% by mass) of the toner particles. It is more preferably 3% by mass or more, and further preferably 3% by mass or more. Within these ranges, the control range of image glossiness can be further expanded. The content of the liquid crystal compound is preferably 25% by mass or less, more preferably 20% by mass or less, and 15% by mass or less with respect to the total mass (100% by mass) of the toner particles. It is more preferably present, and particularly preferably 8% by mass or less. Within these ranges, the influence on the fixing property, heat resistance, etc. of the electrophotographic toner itself is smaller, and the toner exhibits better characteristics as an electrophotographic toner.

[Bundling resin]
The toner matrix particles according to one embodiment of the present invention include a binder resin. The binder resin has an appropriate viscosity of the toner and suppresses bleeding when applied to paper, so that it acts to improve fine line reproducibility and dot reproducibility.

The binder resin is not particularly limited, and a known resin can be used.

Examples of the binder resin include crystalline resin and amorphous resin, but it is preferable to include amorphous resin, and more preferably to contain amorphous resin and crystalline resin.

The amorphous resin is a resin that does not have a melting point and has a relatively high glass transition point (Tg) when differential scanning calorimetry (DSC) is performed. At this time, the glass transition point (Tg) of the amorphous resin is not particularly limited, but is preferably 30 ° C. or higher, more preferably 40 ° C. or higher, and even more preferably 45 ° C. or higher. Within these ranges, the heat-resistant storage stability is further improved. The glass transition point (Tg) of the amorphous resin is not particularly limited, but is preferably 80 ° C. or lower, and more preferably 65 ° C. or lower. Within these ranges, it becomes easier to make the heat-sensitive material transparent at the time of fixing, and it becomes easier to reset the heat history before the heat treatment.

As a combination with the low molecular weight compound which is the heat sensitive material, it is preferable that the melting point of the low molecular weight compound is higher than the glass transition point of the amorphous resin. At this time, the control range of the image glossiness can be further expanded. It is presumed that the reason for this is that by inhibiting the aggregation of the low molecular weight compound by the main chain motion of the amorphous resin during cooling, the low molecular weight compound can be crystallized with a high degree of dispersion. Ru. From the same viewpoint, a preferable example of the combination with the low molecular weight compound which is the heat sensitive material is that the glass transition point of the amorphous resin is 45 ° C. or higher and the melting point of the low molecular weight compound which is the heat sensitive material is 60. ° C or higher and 90 ° C or lower. The glass transition point (Tg) of the amorphous resin can be measured by a differential calorimetry device (DSC). The glass transition point (Tg) can be controlled by those skilled in the art by the composition of the resin.

The crystalline resin refers to a resin having a clear endothermic peak instead of a stepwise endothermic change in differential scanning calorimetry (DSC). A clear endothermic peak specifically means a peak in which the half width of the endothermic peak is within 15 ° C. when measured at a temperature rise rate of 10 ° C./min in differential scanning calorimetry (DSC). do.

The amorphous resin is not particularly limited, and examples thereof include an amorphous polyester resin and a vinyl resin. Among these, vinyl resin is more preferable from the viewpoint of excellent environmental stability of the amount of charge. The vinyl resin is a resin obtained by polymerization using at least a vinyl monomer. Specific examples of the vinyl resin include styrene resin, acrylic resin, styrene / acrylic copolymer resin (styrene / acrylic resin), and the like. Among these, a styrene / acrylic copolymer resin formed by using a styrene monomer and a (meth) acrylic acid ester monomer is preferable.

The styrene monomer is not particularly limited, but for example, styrene, o-methylstyrene, m-methylstyrene, p-methylstyrene, α-methylstyrene, p-phenylstyrene, p-ethylstyrene, 2,4-. Examples thereof include dimethylstyrene, pt-butylstyrene, pn-hexylstyrene, pn-octylstyrene, pn-nonylstyrene, pn-decylstyrene, pn-dodecylstyrene and the like. Among these, styrene is preferable.

The (meth) acrylic acid ester monomer is not particularly limited, and examples thereof include the acrylic acid ester monomer and the methacrylic acid ester monomer shown below. Examples of the acrylic acid ester monomer include methyl acrylate, ethyl acrylate, n-propyl acrylate, isopropyl acrylate, n-butyl acrylate, isobutyl acrylate, t-butyl acrylate, n-octyl acrylate, 2-ethylhexyl acrylate, and stearyl acrylate. , Lauryl acrylate, phenyl acrylate phenyl and the like. Examples of the methacrylic acid ester monomer include methyl methacrylate, ethyl methacrylate, n-propyl methacrylate, isopropyl methacrylate, n-butyl methacrylate, isobutyl methacrylate, t-butyl methacrylate, n-octyl methacrylate, and 2-ethylhexyl methacrylate. Examples thereof include stearyl methacrylate, lauryl methacrylate, phenyl methacrylate, diethylaminoethyl methacrylate and dimethylaminoethyl methacrylate. Among these, n-butyl acrylate is preferable.

These styrene monomer, acrylic acid ester monomer, or methacrylic acid ester monomer may be used alone or in combination of two or more.

In addition to the above-mentioned copolymer formed only of the styrene monomer and the (meth) acrylic acid ester monomer, the styrene / acrylic resin may be used in combination with other vinyl monomers. It may be a copolymer formed in the above. Hereinafter, vinyl monomers that can be used in combination when forming the styrene / acrylic resin referred to in the present invention will be exemplified, but the vinyl monomers that can be used in combination are not limited to those shown below.

(1) Olefins Ethylene, propylene, isobutylene (2) Vinyl esters Vinyl propionate, vinyl acetate, vinyl benzoate (3) Vinyl ethers Vinyl methyl ether, vinyl ethyl ether (4) Vinyl ketones Vinyl methyl ketone, vinyl ethyl ketone , Vinyl hexyl ketone (5) N-vinyl compounds N-vinylcarbazole, N-vinylindole, N-vinylpyrrolidone (6) Other vinyl compounds such as vinylnaphthalene and vinylpyridine, acrylonitrile, methacrylonitrile, acrylamide, etc. Acrylic acid or methacrylic acid derivative, etc.

It is also possible to prepare a resin having a crosslinked structure by using a polyfunctional vinyl monomer. Furthermore, it is also possible to use a vinyl monomer having an ionic dissociation group in the side chain. Specific examples of the ionic dissociation group include a carboxy group, a sulfonic acid group, a phosphoric acid group and the like. Specific examples of these vinyl monomers having a carboxy group are shown below.

Specific examples of the vinyl monomer having a carboxy group include acrylic acid, methacrylic acid, maleic acid, itaconic acid, silicic acid, fumaric acid, maleic acid monoalkyl ester, itaconic acid monoalkyl ester and the like. ..

As the vinyl monomer that can be used in combination when forming the styrene / acrylic resin, a vinyl monomer having a carboxyl group is preferable, and acrylic acid or methacrylic acid is more preferable.

The method for forming the styrene / acrylic resin is not particularly limited, and examples thereof include a method of polymerizing a monomer using a known oil-soluble or water-soluble polymerization initiator. If necessary, known chain transfer agents such as, for example, n-octyl-3-mercaptopropionate may be used.

When the styrene / acrylic resin is formed, the contents of the styrene monomer and the acrylic acid ester monomer are not particularly limited, and are appropriately adjusted from the viewpoint of controlling the softening temperature of the binder resin and the glass transition point. It is possible. Specifically, the content of the styrene monomer is preferably 40 to 95% by mass, more preferably 50 to 80% by mass, based on the whole monomer. The content of the acrylic acid ester monomer is preferably 5 to 60% by mass, more preferably 20 to 50% by mass, based on the total amount of the monomer.

As the amorphous resin, a synthetic product or a commercially available product may be used. The method for forming the styrene / acrylic resin is not particularly limited, and examples thereof include a method of polymerizing a monomer using a known oil-soluble or water-soluble polymerization initiator. Specific examples of the oil-soluble polymerization initiator include the following azo-based or diazo-based polymerization initiators and peroxide-based polymerization initiators.

The azo-based or diazo-based polymerization initiator is not particularly limited, and is, for example, 2,2'-azobis- (2,4-dimethylvaleronitrile), 2,2'-azobisisobutyronitrile, 1,1. Examples thereof include'-azobis (cyclohexane-1-carbonitrile), 2,2'-azobis-4-methoxy-2,4-dimethylvaleronitrile, azobisisobutyronitrile and the like.

The peroxide-based polymerization initiator is not particularly limited, and for example, benzoyl peroxide, methyl ethyl ketone peroxide, diisopropyl peroxycarbonate, cumenehydroperoxide, t-butylhydroperoxide, di-t-butyl peroxide, and the like. Dicumyl peroxide, 2,4-dichlorobenzoyl peroxide, lauroyl peroxide, 2,2-bis- (4,4-t-butylperoxycyclohexyl) propane, tris- (t-butylperoxy) triazine, etc. Can be mentioned.

Further, when forming styrene / acrylic resin particles by the emulsion polymerization method, a water-soluble radical polymerization initiator can be used. The water-soluble radical polymerization initiator is not particularly limited, and examples thereof include persulfates such as potassium persulfate and ammonium persulfate, azobisaminodipropane acetate, azobiscyanovaleric acid and its salts, and hydrogen peroxide. ..

For dispersion, it is also preferable to polymerize in the presence of an appropriately known surfactant (for example, anionic surfactant such as polyoxyethylene (2) sodium dodecyl ether sulfate, sodium dodecyl sulfate, dodecylbenzene sulfonic acid). ..

The polymerization temperature varies depending on the monomer used and the type of the polymerization initiator, but is preferably 50 to 100 ° C, more preferably 55 to 90 ° C. The polymerization time varies depending on the type of monomer and polymerization initiator used, but is preferably 2 to 12 hours, for example.

The styrene / acrylic resin particles formed by the emulsification polymerization method may have two or more layers made of resins having different compositions. In this case, as a production method, a polymerization initiator and a polymerizable monomer are added to a dispersion of resin particles prepared by an emulsion polymerization treatment (first-stage polymerization) according to a conventional method, and this system is polymerized. A multi-stage polymerization method for processing (second-stage polymerization) can be adopted.

The amorphous resin preferably has a weight average molecular weight (Mw) in the range of 5,000 to 150,000, preferably in the range of 10,000 to 70,000, from the viewpoint of easily controlling its plasticity. It is more preferable to have it. The weight average molecular weight (Mw) can be measured by the method described later.

The amorphous resin may be used alone or in combination of two or more.

The content of the amorphous resin is not particularly limited, but is preferably 50% by mass or more, more preferably 70% by mass or more, based on the total mass (100% by mass) of the binder resin. It is more preferably 80% by mass or more, and particularly preferably 85% by mass or more. Within this range, the environmental stability of the charged amount is more excellent. The content of the amorphous resin is 100% by mass or less, preferably 99% by mass or less, and 95% by mass or less, based on the total mass (100% by mass) of the binder resin. Is more preferable, and 90% by mass or less is further preferable. Within this range, the low temperature fixability is more excellent.

The crystalline resin is not particularly limited, and examples thereof include a crystalline polyester resin, a crystalline polyurethane resin, a crystalline polyurea resin, a crystalline polyamide resin, and a crystalline polyether resin. Among these, a crystalline polyester resin is preferable from the viewpoint of low-temperature fixability.

The crystalline polyester resin is not particularly limited, and examples thereof include a crystalline polyester resin formed by using a polyvalent alcohol or a derivative thereof and a polyvalent carboxylic acid or a derivative thereof as monomers. ..

The polyhydric alcohol or a derivative thereof is not particularly limited, and is, for example, ethylene glycol, 1,3-propanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 1,7. -Heptanediol, 1,8-octanediol, 1,9-nonanediol, 1,10-decanediol, 1,11-undecanediol, 1,12-dodecanediol, 1,13-tridecanediol, 1,14 -Tetradecanediol, 1,18-octadecanediol, 1,20-eicosanediol and the like can be mentioned. Among these, 1,12-dodecanediol is preferable. These can be used alone or in combination of two or more.

The polyvalent carboxylic acid or a derivative thereof is not particularly limited, and is, for example, oxalic acid, malonic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, 1,9-nonandicarboxylic acid. Acid, 1,10-decandicarboxylic acid (dodecanedioic acid), 1,11-undecanedicarboxylic acid, 1,12-dodecanedicarboxylic acid, 1,13-tridecanedicarboxylic acid, 1,14-tetradecanediocarboxylic acid, 1, Examples thereof include 16-hexadecanedicarboxylic acid, 1,18-octadecanedicarboxylic acid, terephthalic acid, isophthalic acid, orthophthalic acid, t-butylisophthalic acid, 2,6-naphthalenedicarboxylic acid and 4,4'-biphenyldicarboxylic acid. Further, these halides, lower alkyl esters, acid anhydrides and the like can also be mentioned. Of these, sebacic acid is preferred. These can be used alone or in combination of two or more.

Further, the crystalline polyester resin is formed by using other monomers in combination with the above-mentioned polyhydric alcohol or its derivative and the copolymer formed only by the polyhydric alcohol or its derivative. It may be a copolymer to be used.

The crystalline resin is preferably a hybrid crystalline resin having a crystalline polymerized segment and an amorphous polymerized segment. The hybrid crystalline resin may be in the form of a block copolymer of a crystalline polymerized segment and an amorphous polymerized segment (block copolymer), or the side chain of the crystalline polymerized segment may be a non-crystalline polymerized segment. It may be in the form bonded to the main chain (graft copolymer), or vice versa. A graft copolymer is preferable.

The hybrid crystalline resin is not particularly limited, and examples thereof include a hybrid crystalline polyester resin in which a vinyl polymerized segment and a crystalline polyester polymerized segment are chemically bonded. At this time, it is preferable that the vinyl polymerized segment and the crystalline polyester polymerized segment are bonded via both reactive monomers.

The crystalline polyester polymerized segment is made of a crystalline polyester resin. By using the hybrid crystalline polyester resin, it becomes easier to blend with amorphous resins such as styrene and acrylic resins, so that the crystalline polyester resin can be more evenly dispersed in the toner matrix particles, and the low temperature fixability is improved. Can be done. Further, since the dispersibility of the colorant in the toner matrix particles is improved, the low temperature fixability, the scattering property, and the image quality can be improved. Further, since the dispersibility of the heat-sensitive material in the toner matrix particles is improved, the control range of the image glossiness can be further expanded.

The crystalline polyester polymerized segment constituting the hybrid crystalline polyester resin is a crystalline polyester produced by subjecting a polyvalent carboxylic acid or a derivative thereof and a polyvalent alcohol or a derivative thereof to a polycondensation reaction in the presence of a catalyst. Consists of resin. Here, since the specific types of the polyvalent carboxylic acid or its derivative and the polyhydric alcohol or its derivative are as described above, detailed description thereof will be omitted here. The preferred monomer is also the same as the description of the crystalline polyester resin as the crystalline resin described above.

The vinyl polymerized segment constituting the hybrid crystalline polyester resin is composed of the vinyl resin. Here, as the vinyl monomer, the above-mentioned monomer can be similarly used as the monomer constituting the vinyl resin, and therefore detailed description thereof will be omitted here. The preferred monomer is also the same as the description of the vinyl resin as the amorphous resin described above.

The content (hybridization rate) of the vinyl polymerized segment in the hybrid crystalline polyester resin is not particularly limited, but is preferably in the range of 5 to 30% by mass, and preferably in the range of 5 to 20% by mass. Is more preferable, and more preferably in the range of 5 to 10% by mass.

-Bi-reactive monomer "Bi-reactive monomer" is a monomer that binds a crystalline polyester polymerized segment and a vinyl polymerized segment, and is a hydroxy group that forms a crystalline polyester polymerized segment in the molecule. , A monomer having both a group selected from a carboxy group, an epoxy group, a primary amino group and a secondary amino group, and an ethylenically unsaturated group forming a vinyl polymerization segment. The bireactive monomer is preferably a monomer having a hydroxy group or a carboxy group and an ethylenically unsaturated group. More preferably, it is a monomer having a carboxy group and an ethylenically unsaturated group. That is, it is preferably a vinylcarboxylic acid. Specific examples of the bireactive monomer include acrylic acid, methacrylic acid, fumaric acid, maleic acid, and esters of these hydroxyalkyls (1 to 3 carbon atoms). Among these, acrylic acid, methacrylic acid or fumaric acid is preferable, and acrylic acid is more preferable, from the viewpoint of reactivity. The bireactive monomers may be used alone or in combination of two or more. The crystalline polyester polymerized segment and the vinyl polymerized segment are bonded via the bireactive monomer.

The amount of both reactive monomers used is 1 to 1 to 100 parts by mass of the total amount of vinyl monomers constituting the vinyl polymerization segment from the viewpoint of improving the low temperature fixing property, high temperature offset resistance and durability of the toner. 10 parts by mass is preferable, and 4 to 8 parts by mass is more preferable.

As the crystalline resin, a commercially available product or a synthetic product may be used. As a method for producing the hybrid crystalline polyester resin, an existing general scheme can be used. The following three are typical methods.

(1) A styrene monomer and (meth) for forming a vinyl polymerized segment by prepolymerizing a crystalline polyester polymerized segment and reacting the crystalline polyester polymerized segment with a bireactive monomer. A method for forming a hybrid crystalline polyester resin by reacting an acrylic acid ester monomer or the like.

(2) The vinyl polymerization segment is polymerized in advance, the vinyl polymerization segment is reacted with the bireactive monomer, and the polyvalent carboxylic acid and the polyhydric alcohol for forming the crystalline polyester polymerization segment are further reacted. A method of forming a crystalline polyester polymerized segment by allowing the polymer to form a crystalline polyester polymerized segment.

(3) A method in which a crystalline polyester polymerized segment and a vinyl polymerized segment are polymerized in advance, and both reactive monomers are reacted with each of them to bond them together.

Any of the above-mentioned production methods can be used, but the above-mentioned method (2) is preferable. Specifically, a polyvalent carboxylic acid or a derivative thereof and a polyhydric alcohol or a derivative thereof forming a polyester polymerization segment, and a vinyl monomer and a bireactive monomer forming a vinyl polymerization segment are mixed and polymerization is started. It is preferable to add an agent to carry out addition polymerization of the vinyl monomer and the bireactive monomer to form a vinyl polymerization segment, and then add an esterification catalyst to carry out a polycondensation reaction.

Here, examples of the polymerization initiator used for the polymerization of the vinyl polymerization segment include those similar to those mentioned in the above description of the styrene / acrylic resin as the amorphous resin.

Here, a known catalyst can be used as the catalyst for synthesizing the crystalline polyester polymerized segment (or the crystalline polyester resin). Examples of the esterification catalyst include tin compounds such as dibutyltin oxide and tin 2-ethylhexanoate (II), titanium diisopropyrate bistriethanolaminate, and tetrabutoxytitanium (titanium tetrabutoxide, Ti (OBu) ₄ ). Examples thereof include titanium compounds such as tetraoctoxytitanium and tetrastearyloxytitanium. Examples of the esterification co-catalyst include gallic acid and the like.

The melting point of the crystalline resin is not particularly limited, but is preferably in the range of 30 to 80 ° C. The melting point of the crystalline resin can be measured by a DSC (differential calorimetry device). Those skilled in the art can control the melting point of the crystalline resin by the composition of the resin.

It is a low temperature that the weight average molecular weight (Mw) of the crystalline resin is in the range of 5,000 to 50,000 or the number average molecular weight (Mn) is in the range of 2,000 to 10,000. It is preferable from the viewpoint of fixability and stable gloss development in the final image. The weight average molecular weight (Mw) and the number average molecular weight (Mn) of the crystalline resin can be measured by the following methods.

The weight average molecular weight (Mw) and number average molecular weight (Mn) of the amorphous resin and the crystalline resin are determined from the molecular weight distribution measured by GPC (gel permeation chromatography) using polystyrene as a standard substance. Can be done.

More specifically, the sample was added to tetrahydrofuran (THF) to a concentration of 1 mg / mL, dispersed at room temperature for 5 minutes using an ultrasonic disperser, and then treated with a membrane filter having a pore size of 0.2 μm. To prepare the sample solution. Using a GPC device HLC-8120GPC (manufactured by Tosoh Corporation) and a column "TSKguardcolum + TSKgel SuperHZM-M3 series" (manufactured by Tosoh Corporation), THF was used as a carrier solvent at a flow rate of 0.2 mL / min while maintaining the column temperature at 40 ° C. Shed with. 10 μL of the prepared sample solution is injected into the GPC device together with the carrier solvent, and the sample is detected using a refractive index detector (RI detector). Then, the molecular weight distribution of the sample is calculated using the calibration curve measured using 10 points of monodisperse polystyrene standard particles.

The crystalline resin may be used alone or in combination of two or more.

When an amorphous resin and a crystalline resin are used as the binder resin, the amorphous resin contains at least one selected from the group consisting of styrene resin, acrylic resin and styrene / acrylic resin, and the crystalline resin is It preferably contains a hybrid crystalline polyester resin. Further, it is more preferable that the amorphous resin contains a styrene / acrylic resin and the crystalline resin contains a hybrid crystalline polyester resin. With these combinations, the toner has a lower viscosity and higher sharp meltability can be obtained at the time of melting.

The content of the binder resin is not particularly limited, but is preferably 30% by mass or more, more preferably 50% by mass or more, and 50% by mass with respect to the total mass (100% by mass) of the toner particles. % Or more is more preferable. The content of the binder resin is preferably 99% by mass or less, more preferably 90% by mass or less, and 80% by mass or less with respect to the total mass (100% by mass) of the toner particles. It is more preferable to have.

[Colorant]
The toner particles according to the embodiment of the present invention contain a colorant. As the colorant, generally known dyes or pigments can be used.

The colorant for obtaining black toner is not particularly limited, and examples thereof include pigments such as carbon black, magnetic materials, and iron / titanium composite oxide black. Here, the carbon black is not particularly limited, and examples thereof include channel black, furnace black, acetylene black, thermal black, and lamp black. Further, examples of the magnetic material include ferrite, magnetite and the like.

The colorant for obtaining the yellow toner is not particularly limited, but for example, C.I. I. Dyes such as Solvent Yellow 19, 44, 77, 79, 81, 82, 93, 98, 103, 104, 112, 162, C.I. I. Pigment Yellow 14, 17, 74, 93, 94, 138, 155, 180, 185 and the like.

The colorant for obtaining magenta toner is not particularly limited, but for example, C.I. I. Dyes such as Solvent Red 1, 49, 52, 58, 63, 111, 122, C.I. I. Pigment Red 5, 48: 1, 53: 1, 57: 1, 122, 139, 144, 149, 166, 177, 178, 222 and the like.

The colorant for obtaining cyan toner is not particularly limited, but for example, C.I. I. Dyes such as Solvent Blue 25, 36, 60, 70, 93, 95, C.I. I. Pigment Blue 1, 7, 15, 15, 15: 3, 60, 62, 66, 76 and the like.

As the colorant, a synthetic product or a commercially available product may be used. Examples of commercially available products include Legal (registered trademark) 330R manufactured by Cabot Corporation.

The colorant for obtaining the toner of each color may be used alone or in combination of two or more for each color.

The content of the colorant is not particularly limited, but is preferably 1% by mass or more, more preferably 2% by mass or more, and 5% by mass with respect to the total mass (100% by mass) of the toner particles. The above is more preferable. Within these ranges, sufficient coloring power can be obtained. The content of the colorant is preferably 30% by mass or less, more preferably 25% by mass or less, and 20% by mass or less with respect to the total mass (100% by mass) of the toner particles. Is more preferable. Within these ranges, the colorant does not release from the toner and adhere to the carrier, and the chargeability is stable, so that a high-quality image can be obtained.

[Release agent]
The toner matrix particles according to one embodiment of the present invention may contain a mold release agent. The release agent is not particularly limited, and a known wax or the like can be used.

The wax is not particularly limited, and examples thereof include low molecular weight polypropylene, polyethylene, oxidized low molecular weight polypropylene, polyolefins such as polyethylene, paraffin, and synthetic ester wax. Among these, synthetic ester wax is preferable from the viewpoint of low melting point and low viscosity, behenic acid behenic acid, glycerin tribehenate, pentaerythritol tetrabehenate and the like are more preferable, and behenic acid behenic acid is further preferable.

As the release agent, a synthetic product or a commercially available product may be used.

The release agent may be used alone or in combination of two or more.

The content of the release agent is not particularly limited, but is preferably 1% by mass or more, more preferably 3% by mass or more, and 4% by mass with respect to the total mass (100% by mass) of the toner particles. % Or more is more preferable. The content of the release agent is preferably 30% by mass or less, more preferably 20% by mass or less, and 15% by mass or less with respect to the total mass (100% by mass) of the toner particles. It is more preferable to have.

[Other internal additives]
The toner matrix particles according to one embodiment of the present invention may further contain other internal additives. Examples of such other internal additives include, but are not limited to, a charge control agent, an ultraviolet absorber, and the like. The charge control agent is a substance capable of giving positive or negative charge by triboelectric charge, and is not particularly limited as long as it is colorless, and known positive charge control agents and negative charge control agents. Agents and the like can be used. The content of the charge control agent is not particularly limited, but is preferably 0.01% by mass or more, more preferably 0.1% by mass or more, based on the total mass (100% by mass) of the toner particles. preferable. The content of the charge control agent is preferably 30% by mass or less, more preferably 10% by mass or less, based on the total mass (100% by mass) of the toner particles.

[Average particle size of toner matrix particles]
The average particle size of the toner matrix particles is not particularly limited, but is preferably 4 μm or more in terms of volume-based median diameter (D50). The average particle size of the toner matrix particles is preferably 10 μm or less, and more preferably 7 μm in terms of the volume-based median diameter (D50). Within these ranges, the transfer efficiency is high, the image quality of halftone is improved, and the image quality of fine lines, dots, etc. is improved.

The volume-based median diameter (D50) of the toner matrix particles is a computer system (Beckman Coulter) equipped with the data processing software "Software V3.51" on "Coulter Counter 3" (manufactured by Beckman Coulter Co., Ltd.). It is measured and calculated using a measuring device connected to (manufactured by Co., Ltd.). Specifically, 0.02 g of the measurement sample (toner) is mixed with 20 mL of a surfactant solution (for the purpose of dispersing the surfactant particles, for example, a neutral detergent containing a surfactant component diluted 10-fold with pure water). After adding to (activator solution) and acclimatizing, ultrasonic dispersion is performed for 1 minute to prepare a toner matrix particle dispersion, and this toner matrix particle dispersion is used as "ISOTON II" (Beckman Coulter) in a sample stand. Inject into a beaker containing (manufactured by Co., Ltd.) with a pipette until the indicated concentration of the measuring device reaches 8%. Here, by setting this concentration range, it is possible to obtain a reproducible measured value. Then, in the measuring device, the number of measured particles is 25,000, the aperture diameter is set to 50 μm, the frequency value is calculated by dividing the range of 1 to 30 μm, which is the measurement range, into 256, and the frequency value is calculated from the one with the largest volume integration fraction to 50. The particle diameter of% is defined as the volume-based median diameter (D50).

The average circularity of the toner matrix particles is preferably in the range of 0.900 to 1.000, and more preferably in the range of 0.940 to 0.995, from the viewpoint of improving the low temperature fixability. preferable. The average circularity is a value measured using "FPIA-2100" (manufactured by Sysmex Corporation). Specifically, the toner matrix particles are moistened with an aqueous surfactant solution, ultrasonically dispersed for 1 minute, and then dispersed, and then HPF is used in the measurement condition HPF (high magnification imaging) mode using "FPIA-2100". The measurement is performed at an appropriate concentration of 4000 detections. The circularity is calculated by the following formula.

The average circularity is an arithmetic mean value obtained by adding the circularity of each particle and dividing by the total number of measured particles.

[External agent]
The toner particles according to the embodiment of the present invention have particles such as known inorganic particles and organic particles on the surface of the toner matrix particles from the viewpoint of improving the fluidity, chargeability, cleaning property, etc. of the electrophotographic toner. It is preferable to contain a lubricant or the like as an external additive. Among these, inorganic particles are preferable.

The inorganic particles are not particularly limited, and are, for example, inorganic oxide particles such as silica particles, alumina particles, and titanium oxide particles, inorganic stearate compound particles such as aluminum stearate particles and zinc stearate particles, and strontium titanate particles. Examples thereof include inorganic titanoic acid compound particles such as zinc titanate particles. These inorganic particles may be surface-modified with a silane coupling agent, a titanium coupling agent, a higher fatty acid, a silicone oil, or the like in order to improve heat storage stability and environmental stability. Among these, hydrophobic inorganic particles are preferable, and hydrophobic silica particles or hydrophobic titanium oxide particles are more preferable.

The particle size of the external additive is not particularly limited, but the number average primary particle size is preferably 2 nm or more, and more preferably 10 nm or more. Further, as the particle size of the external additive, the number average primary particle size is preferably 2000 nm or less, and more preferably 800 nm or less. The "number average primary particle diameter" refers to a value obtained by binarizing a scanning electron micrograph of an external additive, calculating a horizontal ferret diameter for 10,000 particles, and taking the average.

The external additive may be used alone or in combination of two or more.

The addition rate of the external additive is not particularly limited, but is preferably 0.05% by mass or more, more preferably 0.1% by mass or more, based on the total mass (100% by mass) of the toner particles. It is preferably 1% by mass or more, and more preferably 1% by mass or more. The addition rate of the external additive is preferably 5% by mass or less, more preferably 3% by mass or less, and 2% by mass or less, based on the total mass (100% by mass) of the toner particles. It is more preferable to have.

[Composition of toner particles]
The composition of the toner matrix particles and the toner particles is not particularly limited, and is, for example, ESCA (X-ray photoelectron spectroscopy), SEM (scanning electron microscope), GC-MS (gas chromatography-mass spectrometry), FT-IR. The presence or absence and content of each component can be confirmed by chemical analysis such as (Fourier transform infrared spectroscopy).

[Manufacturing method of toner for electrophotographic]
The method for producing an electrophotographic toner according to an embodiment of the present invention is not particularly limited. When producing a toner containing additives such as a binder resin, a colorant and a heat-sensitive material, it is preferable to use a production method using an emulsifying and agglutination method in which the particle size and shape can be easily controlled.

Such a manufacturing method
(A) Bundling resin particle dispersion liquid preparation step for preparing a dispersion liquid of the binder resin particles;
(B) Colorant particle dispersion preparation step for preparing a colorant particle dispersion;
(C) Heat-sensitive material particle dispersion liquid preparation step for preparing a heat-sensitive material particle dispersion liquid;
(D) A flocculant is added to an aqueous medium in which the binder resin particles, the colorant particles and the heat-sensitive material particles are present, and the salting out is promoted, and at the same time, the coagulation and fusion are performed to form the associated particles. Meeting process;
(E) Aging step of forming toner matrix particles by controlling the shape of associated particles;
(F) A filtration and cleaning step of filtering out toner matrix particles from an aqueous medium and removing a surfactant or the like from the toner matrix particles;
(G) A drying step of drying the washed toner matrix particles;
(H) An external additive addition step of adding an external additive to the dried toner matrix particles;
It is preferable to include each step of. Hereinafter, the steps (a) to (c) will be described.

(A) Bundling resin particle dispersion liquid preparation step In this step, resin particles are formed by conventionally known emulsion polymerization or the like, and the resin particles are aggregated and fused to form binding resin particles. As an example, a dispersion of binder resin particles is obtained by charging and dispersing the monomers constituting the binder resin (polymerizable monomer) in an aqueous medium and polymerizing these monomers with a polymerization initiator. To make.

Further, as a method for obtaining a binder resin particle dispersion liquid, in addition to the method of polymerizing a monomer with a polymerization initiator in the above-mentioned aqueous medium, for example, a dispersion treatment is performed in an aqueous medium without using a solvent. Examples thereof include a method in which a binder resin is dissolved in a solvent such as ethyl acetate to prepare a solution, the solution is emulsified and dispersed in an aqueous medium using a disperser, and then a desolvation treatment is performed.

If necessary, known polymerization initiators such as dit-butyl peroxide and potassium persulfate, known chain transfer agents such as n-octyl-3-mercaptopropionate, tetrabutoxytitanium (titanium tetto). It is also preferred to polymerize the polymerizable monomer in the presence of known esterification catalysts such as labtoxide, Ti (OBu) _4).

For dispersion, it is also preferable to polymerize in the presence of an appropriately known surfactant (for example, anionic surfactant such as polyoxyethylene (2) sodium dodecyl ether sulfate, sodium dodecyl sulfate, dodecylbenzene sulfonic acid). ..

It is also preferable to use known basic compounds such as ammonia and sodium hydroxide in order to facilitate the emulsification of the binder resin containing an organic acid group.

If necessary, the binding resin may contain the above-mentioned mold release agent (wax) in advance. A release agent particle dispersion may be prepared separately from the binder resin particle dispersion and mixed so that the release agent particles are present in the aqueous medium of the association step (d).

The binder resin particles may have a multilayer structure of two or more layers made of binder resins having different compositions, and the binder resin particles having such a structure are usually those having a two-layer structure, for example. A binder resin particle dispersion liquid is prepared by an emulsion polymerization treatment (first stage polymerization) according to the method, a polymerization initiator and a polymerizable monomer are added to the dispersion liquid, and this system is polymerized (second stage polymerization). It can be obtained by a method of step polymerization).

In the binder resin particle dispersion liquid of (1) above, the concentration of the binder resin is not particularly limited, but is 0.1% by mass or more and 40% by mass or less with respect to the total mass (100% by mass) of the dispersion liquid. It is preferable to have.

The volume-based median diameter of the binder resin particles in the dispersion is preferably 50 to 300 nm. The volume-based median diameter of the binder resin particles in the dispersion can be measured by a dynamic light scattering method using "Microtrac UPA-150" (manufactured by Nikkiso Co., Ltd.).

(B) Colorant particle dispersion liquid preparation step This step is a step of preparing a dispersion liquid of colorant particles by dispersing the colorant in the form of fine particles in an aqueous medium.

Dispersion of the colorant can be performed by utilizing mechanical energy. For example, "Clairemix (registered trademark)", which is a stirring device manufactured by M-Technique Co., Ltd., can be used. At this time, for the purpose of improving the dispersibility, the colorant is dispersed in the presence of a surfactant such as sodium dodecyl sulfate, which will be described later in the description of the process for preparing the heat-sensitive material particle dispersion liquid (c). It is also preferable to do.

In the colorant particle dispersion liquid, the concentration of the colorant is not particularly limited, but is preferably 5% by mass or more and 40% by mass or less with respect to the total mass (100% by mass) of the dispersion liquid.

The volume-based median diameter of the colorant particles in the dispersion is preferably 10 to 300 nm, more preferably 50 to 200 nm. The volume-based median diameter of the colorant particles can be measured using an electrophoretic light scattering photometer "ELSZ-1000" (manufactured by Otsuka Electronics Co., Ltd.).

(C) Preparation step of heat-sensitive material particle dispersion liquid This step is a step of preparing a dispersion liquid of heat-sensitive material particles by dispersing the heat-sensitive material in the form of fine particles in an aqueous medium. In preparing the heat-sensitive material particle dispersion, first, an emulsion of the heat-sensitive material is prepared. Examples of the method for preparing an emulsified solution of heat-sensitive material particles include a method in which a heat-sensitive material is dissolved in an organic solvent to obtain a heat-sensitive material solution, and then the heat-sensitive material solution is emulsified in an aqueous medium.

The method for dissolving the heat-sensitive material in the organic solvent is not particularly limited, and examples thereof include a method in which the heat-sensitive material is added to the organic solvent and stirred and mixed. The amount of the heat-sensitive material added is preferably 10 parts by mass or more and 1000 parts by mass or less, and more preferably 50 parts by mass or more and 200 parts by mass or less with respect to 100 parts by mass of the organic solvent.

Next, the heat-sensitive material solution and the aqueous medium are mixed and stirred using a known disperser such as an ultrasonic homogenizer. As a result, the heat-sensitive material becomes droplets and is emulsified in the aqueous medium to prepare an emulsified solution of the heat-sensitive material.

The amount of the heat-sensitive material solution added is preferably 10 parts by mass or more and 1000 parts by mass or less, and more preferably 50 parts by mass or more and 200 parts by mass or less with respect to 100 parts by mass of the aqueous medium.

Further, the temperatures of the heat-sensitive material solution and the water-based medium at the time of mixing the heat-sensitive material solution and the water-based medium are in the temperature range below the boiling point of the organic solvent, and are preferably 20 ° C. or higher and 80 ° C. or lower. The temperature of the heat-sensitive material solution and the temperature of the water-based medium at the time of mixing the heat-sensitive material solution and the water-based medium may be the same or different from each other, and are preferably the same as each other.

The stirring condition of the disperser is not particularly limited, but when the capacity is 1 to 3 L, the rotation speed thereof is, for example, 7000 rpm or more and 20000 rpm or less. Further, the stirring time may be, for example, a condition of 10 minutes or more and 30 minutes or less.

The heat-sensitive material particle dispersion is prepared by removing the organic solvent from the heat-sensitive material emulsion. Examples of the method for removing the organic solvent from the emulsion of the heat-sensitive material include known methods such as blowing air, heating, depressurizing, or a combination thereof.

After removing the organic solvent, water may be added to a desired concentration.

In the heat-sensitive material particle dispersion liquid, the concentration of the heat-sensitive material is not particularly limited, but is preferably 5% by mass or more and 40% by mass or less with respect to the total mass (100% by mass) of the dispersion liquid.

The volume-based median diameter of the heat-sensitive material particles in the dispersion is preferably 10 to 300 nm, more preferably 50 to 250 nm. The volume-based median diameter of the heat-sensitive material particles can be measured by a dynamic light scattering method using "Microtrack UPA-150" (manufactured by Nikkiso Co., Ltd.).

The organic solvent used in this step is not particularly limited as long as it can dissolve the heat-sensitive material. Specifically, esters such as ethyl acetate and butyl acetate, ethers such as diethyl ether, diisopropyl ether and tetrahydrofuran, ketones such as acetone and methyl ethyl ketone, saturated hydrocarbons such as hexane and heptane, dichloromethane, dichloroethane, and four. Examples thereof include halogenated hydrocarbons such as carbon chloride. Among these, esters are preferable, and ethyl acetate is more preferable. The organic solvent may be used alone or in combination of two or more.

Examples of the aqueous medium used in this step include water or an aqueous medium containing water as a main component, a water-soluble solvent such as alcohols and glycols, and an arbitrary component such as a surfactant and a dispersant. Be done.

Examples of the surfactant include a cationic surfactant, an anionic surfactant, a nonionic surfactant and the like. Examples of the cationic surfactant include dodecyl ammonium chloride, dodecyl ammonium bromide, dodecyl trimethyl ammonium bromide, dodecyl pyridinium chloride, dodecyl pyridinium bromide, hexadecyl trimethyl ammonium bromide and the like. Examples of the anionic surfactant include fatty acid soaps such as sodium stearate and sodium dodecylate, sodium dodecylbenzene sulfonate, sodium dodecyl sulfate, sodium polyoxyethylene lauryl ether sulfate and the like. Examples of the nonionic surfactant include polyoxyethylene dodecyl ether, polyoxyethylene hexadecyl ether, polyoxyethylene nonylphenyl ether, polyoxyethylene lauryl ether, polyoxyethylene sorbitan monooleate ether, and monodecanoyl. Examples include sucrose. Among these, anionic surfactants are preferable, and polyoxyethylene lauryl ether sodium sulfate is more preferable. The surfactant may be used alone or in combination of two or more.

The addition rate of the surfactant is not particularly limited, but is preferably 0.01% by mass or more and 10% by mass or less, and more preferably 0.04% by mass or more 1 with respect to the total mass (100% by mass) of the aqueous medium. It is less than mass%.

The steps from (d) the associative step to (h) the addition of the external additive can be carried out according to various conventionally known methods.

The flocculant used in (d) the associating step is not particularly limited, but one selected from metal salts is preferably used. Examples of the metal salt include monovalent metal salts such as alkali metal salts such as sodium, potassium and lithium; divalent metal salts such as calcium, magnesium, manganese and copper; and trivalent metal salts such as iron and aluminum. And so on. Specific examples of the metal salt include sodium chloride, potassium chloride, lithium chloride, calcium chloride, magnesium chloride, zinc chloride, copper sulfate, magnesium sulfate, manganese sulfate, etc., among which agglomerates in a smaller amount. It is particularly preferable to use a divalent metal salt because it can be used. These may be used alone or in combination of two or more.

Further, in the (d) meeting step, toner particles having a core-shell structure can also be obtained. Specifically, for the toner particles having a core-shell structure, first, the binder resin particles for the core particles, the heat-sensitive material particles, and the colorant particles are aggregated, associated, and fused to prepare the core particles, and then the core. By adding the binder resin particles for the shell layer to the dispersion liquid of the particles and aggregating and fusing the binder resin particles for the shell layer on the surface of the core particles to form a shell layer covering the surface of the core particles. Obtainable.

[Developer]
The toner for electrophotographic according to the embodiment of the present invention may be a magnetic or non-magnetic one-component developer, or may be a two-component developer containing a carrier. The carrier may be, for example, magnetic particles of a metal such as iron, ferrite, or magnetite, or may be magnetic particles of an alloy of these metals with a metal such as aluminum or lead. Ferrite particles are preferably used as the carrier. Further, as the carrier, a coat carrier in which the surface of the magnetic particles is coated with a coating agent such as a resin, or a dispersed carrier in which the magnetic fine powder is dispersed in a binder resin may be used. The resin as a coating agent in the coat carrier is not particularly limited, and for example, acrylic resin, styrene resin, styrene / acrylic copolymer resin (styrene / acrylic resin), olefin resin, silicone resin, polyester resin, fluororesin, etc. Can be mentioned. Among these, an acrylic resin is preferable, and a copolymer resin formed by using cyclohexyl methacrylate and methyl methacrylate is more preferable. Examples of these monomer mass ratios include 1: 1. The resin as the binder resin for the dispersed carrier is not particularly limited, and examples thereof include acrylic resin, styrene / acrylic copolymer resin (styrene / acrylic resin), polyester resin, fluororesin, and phenol resin. These resins may be used alone or in combination of two or more.

The volume average particle size of the carrier is not particularly limited, but is preferably 20 μm or more, and more preferably 25 μm or more. The volume average particle size of the carrier is preferably 100 μm or less, more preferably 80 μm or less. The volume average particle size of the carrier can be typically measured by a laser diffraction type particle size distribution measuring device "HELOS" (manufactured by Sympathic) equipped with a wet disperser.

The carrier may be used alone or in combination of two or more.
The two-component developer can be produced by mixing such a carrier and an electrophotographic toner using a mixing device. Examples of the mixing device include a Henschel mixer (registered trademark), a Nauter mixer (registered trademark), and a V-type mixer. The blending amount of the electrophotographic toner in producing the two-component developer is preferably in the range of 1 to 10% by mass with respect to the total of 100% by mass of the carrier and the electrophotographic toner.

<Image post-processing method and image post-processing device>
[Image post-processing method]
Another aspect of the present invention relates to an image post-processing method comprising changing the glossiness of the toner image by heat-treating the toner image formed from the above-mentioned electrophotographic toner on a recording medium. .. Here, the toner image on the recording medium is preferably a toner image fixed on the recording medium.

As used herein, the term "heat treatment" refers to a process that involves a change in the surface temperature of the toner image. Examples of such treatment include heat treatment, cooling treatment, post-heating cooling treatment and the like. As one embodiment of the present invention, it is preferable that the heat treatment is performed by an apparatus capable of controlling at least one of a heating temperature and a cooling rate (that is, a desired value or range). For example, the above heat treatment is performed by using a heating means capable of heating to a temperature that changes the glossiness of the toner image on the recording medium, or by setting a cooling rate that changes the glossiness of the toner image on the recording medium. It is preferable that the process includes changing the glossiness of the toner image on the medium. The above heat treatment is performed by using a heating means capable of heating to a temperature that changes the glossiness of the toner image on the recording medium and by setting the cooling rate to change the glossiness of the toner image on the recording medium. It is more preferable that the process includes changing the glossiness of the toner image on the recording medium.

The heating means is not particularly limited as long as it reduces or increases the glossiness of the toner image on the recording medium, and a known contact heating means or a known non-contact heating means can be used.

The contact heating means means a means capable of heating the toner image by directly contacting the surface of the toner image on the recording medium. Specific examples of the contact heating means include (1H) means for contacting a heated pressure roller with a toner image on a recording medium for heating, and (2H) means for heating with a heating plate. Here, when the means for heating by the heating plate of (2H) described above is used, for example, the toner image can be heated by placing the heating plate on the surface of the recording medium on which the toner image is formed. can. In this case, since the toner image and the heating plate are in direct contact with each other, the heating plate is included in the contact heating means.

The non-contact heating means means a means capable of heating the toner image without directly contacting the surface of the toner image on the recording medium. Specific examples of the non-contact heating means include (3H) means for heating with infrared rays using a heater or the like, (4H) means for heating with a heating plate, (5H) means for heating by light irradiation, and (6H) blowing hot air. And the like. Here, when the means for heating by the heating plate of (4H) described above is used, for example, the toner image can be heated by placing a surface of the recording medium on which the toner image is not formed on the heating plate. can. In this case, since the toner image and the heating plate do not come into direct contact with each other, the heating plate is included in the non-contact heating means.

Among these, from the viewpoint that the present invention can be utilized more effectively, the heating means is preferably a contact heating means, and the above-mentioned (1H) heated pressure roller and the toner image on the recording medium are used. It is more preferable that it is a means for contacting and heating. That is, it is preferable that the above heat treatment includes contacting the heated pressure roller with the toner image on the recording medium by using a device including a pressure roller as a heating member.

The cooling may be natural cooling based on the ambient temperature or cooling using cooling means, but when controlling the cooling rate, it is preferable to use cooling means. The cooling means is not particularly limited as long as it increases or decreases the glossiness of the toner image on the recording medium, and a known contact cooling means or a known non-contact cooling means can be used.

The contact cooling means means a means capable of directly contacting the surface of the toner image on the recording medium to cool the toner image. Specific examples of the contact cooling means include (1C) means for contacting and cooling the cooled pressure roller and the toner image on the recording medium, (2C) means for cooling with a cooling plate, and the like.

The non-contact cooling means means a means capable of cooling the toner image without directly contacting the surface of the toner image on the recording medium. Specific examples of the non-contact cooling means include (4C) means for cooling by a cooling plate, (6C) means for blowing cold air to heat, and the like.

The details of the cooling method using the contact cooling means and the cooling plate as the non-contact cooling means are described in the above-mentioned description of the heating method using the contact heating means and the heating plate as the non-contact heating means, respectively. Is changed to a cooling plate.

Further, it is preferable to detect the glossiness before the heat treatment. As a result, the glossiness of the toner image before the heat treatment can be measured. Therefore, after the user confirms the measured glossiness value, whether the glossiness is lower or higher than the glossiness detected by the heat treatment unit 100. Etc. can be selected.

It is also preferable to detect the glossiness after the heat treatment. This makes it possible to confirm whether or not the desired glossiness has been adjusted by the heat treatment. Further, after the glossiness is detected, the glossiness may be adjusted again by heat treatment.

The heating temperature of the toner image during the heat treatment is not particularly limited as long as it is higher than room temperature, but it is preferably equal to or higher than the glass transition point of the heat-sensitive material contained in the toner for electrophotographic. For example, the heating temperature of the toner image during the heat treatment is preferably 60 ° C. or higher, more preferably 80 ° C. or higher, and even more preferably 120 ° C. or higher. Within these ranges, the control range of image glossiness is further improved. The heating temperature of the toner image during the heat treatment is, for example, preferably 250 ° C. or lower, more preferably 200 ° C. or lower, and even more preferably 150 ° C. or lower. Within these ranges, the image glossiness can be controlled more precisely. The heating temperature of the toner image shall be determined from the surface temperature of the toner image. The surface temperature (° C.) of the toner image can be measured using, for example, a temperature measuring device (trade name: FT-H10, manufactured by KEYENCE CORPORATION). The heating temperature of the toner image can be controlled, for example, by changing the set temperature of the heating means.

The cooling rate of the toner image during the heat treatment varies depending on the heat-sensitive material, but is preferably within 1 to 100 ° C./sec, and more preferably within 1 to 70 ° C./sec. Within these ranges, the image glossiness can be made to more reflect the characteristics of the phase of the heat-sensitive material at the surface temperature of the target toner image. The cooling rate (° C./sec) of the toner image during the heat treatment is, for example, the surface temperature of the target toner image obtained by subtracting the ambient temperature (for example, room temperature) from the surface temperature of the target toner image. It can be calculated by dividing the time (sec) until the surface temperature of the toner image first returns to the ambient temperature (for example, room temperature). The method for measuring the surface temperature of the toner image is as described above.

The cooling rate of the toner image during the heat treatment can be controlled by changing the cooling conditions such as the transport speed of the recording medium and the cooling temperature, for example. Here, if the transport speed is increased, the cooling speed becomes faster, and if the transport speed is lowered, the cooling speed of the toner during the heat treatment becomes slower.

The transport speed of the recording medium during the heat treatment is not particularly limited, but is preferably 1 to 600 mm / sec, and a more preferable range is 50 to 500 mm / sec. These ranges are preferred from the standpoint of controlling the cooling rate and productivity.

Regarding the glossiness (image glossiness) of the toner image, for example, using a glossiness measuring instrument (MULTI GROSS 268 Plus manufactured by Konica Minolta Co., Ltd.), the toner image is measured in the long axis direction from the image center point and the image center. The glossiness (%) at an incident angle of 60 ° can be measured for a total of 5 points, 2 points for each of the upper and lower sides of 50 mm, and the average value of the total of 5 points can be calculated as the glossiness (%).

When the contact heating means and the contact cooling means are used, the pressurizing pressure is not particularly limited, but is preferably 10 kPa or more, more preferably 30 kPa or more, and further preferably 50 kPa or more. Within these ranges, the transportability of the media becomes more stable. The pressurizing pressure is not particularly limited, but is preferably 250 kPa or less, more preferably 200 kPa or less, and even more preferably 180 kPa or less. Deterioration of the pressure roller in this range is further suppressed.

Further, in the image post-processing method, it is preferable to adjust the surface temperature of the toner image or the cooling rate of the toner image by a heating means or a cooling means based on the glossiness information specified by the user. In the present specification, the "glossiness information specified by the user" refers to information that specifies how the user wants to adjust the glossiness of the toner image, for example, specific glossiness. It may be a numerical value, it may be a selection of how much the glossiness is reduced or increased from the current glossiness, or it may be a selection of simply reducing or increasing the glossiness from the current glossiness. Here, the glossiness information can be set by inputting by the user on an input screen or the like, for example, when the gloss is controlled by the image post-processing device or when printing is performed by the image forming device.

Further, it is preferable that the surface temperature adjustment of the toner image and the cooling rate adjustment of the toner image are performed based on the relational information regarding the change in the glossiness of the toner image with respect to the surface temperature of the toner image and the cooling rate of the toner image. As a result, the glossiness can be adjusted with higher accuracy by heating or cooling the toner image so that the surface temperature of the toner image or the cooling rate of the toner image is such that the glossiness is specified by the user.

When adjusting the glossiness, the surface temperature of the toner image or the cooling rate of the toner image is selected so that the glossiness is specified by the user, and the toner image is heated or cooled so as to have the surface temperature or the cooling rate. By doing so, the desired glossiness can be adjusted. Further, when the glossiness is changed to a specified glossiness, the surface temperature of the toner image or the cooling rate of the toner image that can be the glossiness may be two or more. In this case, for example, from the viewpoint of energy efficiency, it is preferable to heat at a lower temperature or cool at an ambient temperature or a cooling rate closer to this.

As described above, by using the relational information about the change in the glossiness of the toner image with respect to the surface temperature of the toner image or the cooling rate of the toner image, the toner image gloss temperature having the glossiness specified by the user is accurately determined. It is possible to adjust the glossiness with higher accuracy.

Further, it is preferable to provide a means for detecting the glossiness of the toner image on the recording medium before the heat treatment. As a result, the glossiness of the toner image can be known in advance, so that the glossiness can be adjusted more accurately. However, normally, if the toner image is fixed with the same device and under the same conditions, the glossiness of the toner image becomes the same. Therefore, if the glossiness of the toner image is detected in advance, the glossiness of the toner image is not necessarily the same. There is no need to detect the degree.

[Image post-processing device]
Another embodiment of the present invention is an image post-processing capable of changing the glossiness of the toner image by heat-treating the toner image formed from the above-mentioned electrophotographic toner on a recording medium. Regarding the device. Here, the toner image on the recording medium is preferably a toner image fixed on the recording medium.

The image post-processing apparatus according to the embodiment of the present invention is preferably an apparatus used for performing the above-mentioned image post-processing method.

The image post-processing device according to the embodiment of the present invention is preferably an image post-processing device capable of controlling at least one of a heating temperature and a cooling time (that is, a desired value or range). .. For example, the toner image on the recording medium can be heated by using a heating means capable of heating to a temperature that changes the glossiness of the toner image on the recording medium, or by setting the cooling rate to change the glossiness of the toner image on the recording medium. It is preferable that the image post-processing device is capable of changing the glossiness of the image. Then, by using a heating means capable of heating to a temperature that changes the glossiness of the toner image on the recording medium, and by setting the cooling rate to change the glossiness of the toner image on the recording medium, heat treatment is performed. It is more preferable that the image post-processing device is capable of changing the glossiness of the toner image on the recording medium.

The details of the heating means, the cooling means, the method of adjusting the surface temperature of the toner image, and the method of adjusting the cooling rate of the toner image in the image post-processing apparatus according to the embodiment of the present invention are described in the above description of the image post-processing method. The same is true. Further, the preferable range of the heating temperature and the cooling rate, and the preferable range of the pressurizing pressure by the contact heating means and the contact cooling means are also the same as the description of the above-mentioned image post-processing method.

Specific examples of the contact heating means include, as described above, (1H) means for contacting the heated pressure roller with the toner image on the recording medium to heat, (2H) means for heating with a heating plate, and the like. Be done.

Further, as specific examples of the contact cooling means, as described above, (1C) means for contacting the cooled pressure roller with the toner image on the recording medium for cooling, (2C) means for cooling with a cooling plate, and the like. Can be mentioned.

Specific examples of the non-contact heating means include, as described above, (3H) means for heating with infrared rays using a heater or the like, (4H) means for heating with a heating plate, (5H) means for heating by light irradiation, and (6H). ) Means for heating by blowing hot air can be mentioned.

Further, specific examples of the non-contact cooling means include (4C) means for cooling by a cooling plate, (6C) means for blowing cold air to heat, and the like, as described above.

Hereinafter, an example of a configuration for controlling the glossiness of the means of (1H) and (1C) and (3H), which are preferable heating means, will be described. In addition, in FIG. 1 and FIG. 2 below, each heating means is referred to as a heat treatment unit 100.

(1H) and (1C) The heated pressurizing roller of the means (1H) in which the heated or cooled pressure roller and the toner image on the recording medium are brought into contact with each other to heat or cool, and the toner image on the recording medium. The surface temperature of the toner image is controlled by the heating means in contact with, for example, by a heat treatment unit 100 provided with a heatable pressure roller 300 as the contact heating means (FIG. 1). The heatable pressurizing roller 300 can apply pressure while heating from both sides of the recording medium P. When the recording medium P on which the toner image 121 is fixed is supplied by the transport belt 110, the recording medium P on which the toner image 121 is fixed is sandwiched between the heatable pressure rollers 300, and one roller and the toner image 121 are sandwiched. Pressurizes the toner image 121 in a state of direct contact with the toner image 121. Then, the heatable pressure roller 300 heats the toner image 121 on the recording medium P when the recording medium P passes between them. The heatable pressure roller 300 changes the glossiness of the toner image 121 by heat-treating the toner image 121 by this heating.

Of the heatable pressurizing rollers 300, the other roller does not directly contact the toner image 121, but directly contacts the surface of the recording medium P opposite to the surface on which the toner image 121 is fixed. Even in such a case, any means including a member that directly contacts the toner image 121 and heats the toner image 121 shall be included in the contact heating means.

Further, in the present means, if the recording medium P can be conveyed even if the conveyor belt 110 does not exist, the conveyor belt 110 may not be provided.

Further, as means for contacting and cooling the (1C) cooled pressure roller and the toner image on the recording medium, for example, the above-mentioned (1H) heated pressure roller and the toner image on the recording medium are used. In the heating means, a configuration in which the pressurizing roller that can be heated is changed to the pressurizing roller that can be cooled can be mentioned.

(3H) Means for heating with infrared rays using a heater or the like For controlling the surface temperature of the toner image by the heating means, for example, a heater 101A as a non-contact heating means, a control unit 102, a temperature detection unit 103, and the like. It is performed by the heat treatment unit 100 provided with (FIG. 2). Hereinafter, a case where an IR heater is used as the heater 101A will be described as an example.

When the recording medium P is moved to the heat treatment unit 100 by the transport belt 110, the heater 101A irradiates the toner image 121 on the recording medium P with infrared rays 101a.

The control unit 102 instructs the intensity of the infrared rays to irradiate the heater 101A and the conditions of the irradiation position, and causes the heater 101A to irradiate the infrared rays.

The temperature detection unit 103 detects the surface temperature of the heated toner image 121 and transmits the temperature information to the control unit 102. Further, when the surface temperature of the toner image is selected in advance in order to obtain the glossiness specified by the user, the temperature detection unit 103 sets the surface temperature of the toner image 121 to the selected temperature. It may be possible to tell the control unit whether or not it is present.

Further, in the present means, if the recording medium P can be conveyed even if the conveyor belt 110 does not exist, the conveyor belt 110 may not be provided.

As a means for heating by the heating plate as the contact heating means of (2H), a known means can be used. For example, in paragraph "0052" of Japanese Patent Application Laid-Open No. 2019-101242 and the heating means of FIG. 6, the toner image is formed by replacing the position of the heat treatment portion with the side of the recording medium on which the toner image is formed. The configuration changed to the side of the recording medium can be mentioned. At this time, the heating plate is in direct contact with the surface of the toner image to heat the toner image. Further, a known means can also be used as a means for cooling by the cooling plate as the contact heating means of (2C). For example, in the means for heating by the heating plate as the contact heating means of (2H), the configuration in which the heating plate is changed to a cooling plate and the like can be mentioned. At this time, the cooling plate directly contacts the surface of the toner image to cool the toner image.

As a means for heating by the heating plate as the non-contact heating means of (4H), a known means can be used. For example, paragraph "0052" of JP-A-2019-101242 and the heating means of FIG. 6 can be mentioned. Further, a known means can also be used as a means for cooling by the cooling plate as the non-contact heating means of (4C). For example, in the means for heating by the heating plate as the non-contact heating means of (4H), a configuration in which the heating plate is changed to a cooling plate and the like can be mentioned.

As a means for heating by the light irradiation of (5H), a known means can be used. For example, paragraphs "0053" to "0066" of JP-A-2019-101242, heating means of FIGS. 7 and 8 and the like can be mentioned. When a means for heating by light irradiation is used, it is preferable that the above-mentioned electrophotographic toner, particularly the toner matrix particle, contains a compound that absorbs light in the wavelength range of 280 nm or more and 850 nm or less. Here, the compound that absorbs light in the wavelength range of 280 nm or more and 850 nm or less is not particularly limited, and the above-mentioned heat-sensitive material, colorant, ultraviolet absorber, or the like may also serve as the compound. The maximum emission wavelength of the irradiated light is not particularly limited, but is preferably light in the wavelength range of 280 nm or more and 850 nm or less. Then, the amount of irradiation light is not particularly limited, is preferably 0.01 J / cm ² or more 100 J / cm ² or less.

As a means for blowing and heating the hot air of (6H), a known means can be used. For example, in the means for heating with infrared rays using the heater (3H) described above, there is a configuration in which the heater 101A is changed to a hot air blower, and the basic configuration is the same. Is omitted. Further, as a means for heating by blowing the cold air of (6C), a known means can be used. For example, in the means for heating with infrared rays using the heater (3H) described above, there is a configuration in which the heater 101A is changed to a known cold air blower, and the basic configuration is the same. The explanation will be omitted.

Further, it is preferable to provide a glossiness detection unit for detecting the glossiness in front of the heat treatment unit 100. As a result, the glossiness of the toner image before the heat treatment can be measured. Therefore, after the user confirms the measured glossiness value, whether the glossiness is lower or higher than the glossiness detected by the heat treatment unit 100. Etc. can be selected.

It is also preferable to provide a glossiness detection unit after the heat treatment unit 100. This makes it possible to confirm whether the heat treatment unit 100 has been able to adjust the glossiness to a desired level. Further, the glossiness may be adjusted again by the heat treatment unit 100 after the glossiness is measured by the glossiness detection unit.

Among these, from the viewpoint that the present invention can be utilized more effectively, the image post-processing apparatus preferably includes contact heating means, and the heated or cooled pressure roller is in contact with the toner image on the recording medium. It is more preferable to include the addition.

<Image forming method and image forming device>
[Image formation method]
Another embodiment of the present invention includes a development step of developing an electrostatic latent image with the above-mentioned electrophotographic toner to form a toner image, a transfer step of transferring the toner image onto a recording medium, and a transfer step. The fixing step includes a fixing step of fixing the toner image transferred on the recording medium onto the recording medium using a fixing member and a heat treatment step of heat-treating the toner image fixed on the recording medium. The temperature of the fixing member and the transport speed of the recording medium are set under conditions that can make the heat-sensitive material in the above-mentioned electrophotographic toner transparent, and in the heat treatment step, the above-mentioned image post-processing method is used. The present invention relates to an image forming method for changing the glossiness of a toner image by heat-treating the toner image fixed on a recording medium.

The image forming method according to the embodiment of the present invention includes a developing step, a transfer step, and a fixing step included in a known electrophotographic image forming method. Further, it is preferable to further include a charging step and an exposure step which can be included in a known electrophotographic image forming method before the developing step. Moreover, in addition to these steps, a cleaning step may be further included. The details of these steps will be described below.

(Charging process)
In this step, the electrophotographic photosensitive member is charged. The method of charging is not particularly limited, and for example, a contact or non-contact roller charging method can be used.

(Exposure process)
In this step, an electrostatic latent image is formed on an electrophotographic photosensitive member (electrostatic latent image carrier). The electrophotographic photosensitive member is not particularly limited, and examples thereof include a drum-shaped one made of a known organic photosensitive member.

The formation of the electrostatic latent image is performed by uniformly charging the surface of the electrophotographic photosensitive member by a charging means and exposing the surface of the electrophotographic photosensitive member in an image manner by an exposure means.

The exposure means is not particularly limited, and for example, one composed of LEDs and imaging elements in which light emitting elements are arranged in an array in the axial direction of the photoconductor, a laser optical system, or the like is used.

(Development process)
The developing step is a step of developing an electrostatic latent image with a developing agent containing the above-mentioned electrophotographic toner (for example, a dry developing agent) to form a toner image.

The toner image is formed by using a developing agent containing the above-mentioned electrophotographic toner, for example, a developing sleeve having a built-in magnet and holding the developing agent to rotate, and direct current and / / between the developing sleeve and the photoconductor. Alternatively, it can be performed using a voltage application device that applies an AC bias voltage. More specifically, the above-mentioned electrophotographic toner and the carrier are mixed and stirred, and the friction at that time charges the above-mentioned electrophotographic toner and holds it on the surface of a rotating magnet roller to form a magnetic brush. Toner. Since the magnet roller is arranged near the electrophotographic photosensitive member, a part of the above-mentioned electrophotographic toner constituting the magnetic brush formed on the surface of the magnet roller is an electrophotographic photosensitive member due to an electric attraction. Move to the surface of. As a result, the electrostatic latent image is developed by the above-mentioned electrophotographic toner, and a toner image is formed on the surface of the electrophotographic photosensitive member.

(Transfer process)
In this step, the toner image is transferred onto a recording medium.

The transfer of the toner image onto the recording medium is performed by peeling and charging the toner image on the recording medium.

As the transfer means, for example, a corona transfer device by corona discharge, a transfer belt, a transfer roller, or the like can be used.

Further, in the transfer step, for example, an intermediate transfer body (for example, an intermediate belt) is used, a toner image is first transferred onto the intermediate transfer body, and then the toner image is secondarily transferred onto a recording medium. It can also be performed by transferring the toner image formed on the electrophotographic photosensitive member directly onto the recording medium.

The recording medium is not particularly limited, and is coated printing paper such as plain paper from thin paper to thick paper, high-quality paper, art paper, or coated paper, commercially available Japanese paper and postcard paper, and plastic film for OHP. , Cloth, etc. can be mentioned.

(Fixing process)
In this step, the toner image transferred on the recording medium is fixed on the recording medium. Specifically, for example, a roller fixing method including a fixing roller and a pressure roller provided in a state of being pressure-contacted so as to form a fixing nip portion on the fixing roller can be mentioned.

In the fixing step, it is preferable that the temperature of the fixing member and the transport speed of the recording medium are set to conditions that can make the heat-sensitive material in the toner transparent.

The fixing temperature is not particularly limited, but is preferably 80 ° C. or higher, more preferably 100 ° C. or higher, and even more preferably 120 ° C. or higher. Within these ranges, it becomes easier to eliminate the thermal history of the heat-sensitive material before the heat treatment and during the fixing treatment, and it becomes easier to control the image glossiness by the heat treatment. The fixing temperature is preferably 250 ° C. or lower, more preferably 200 ° C. or lower, and even more preferably 180 ° C. or lower. Within this range, deterioration of the fixing member is further suppressed. The fixing temperature shall be determined from the surface temperature of the toner image. The surface temperature (° C.) of the toner image can be measured using, for example, a temperature measuring device (trade name: FT-H10, manufactured by KEYENCE CORPORATION). The fixing temperature can be controlled, for example, by changing the set temperature of the fixing member at the time of fixing. The temperature of the fixing member at the time of fixing is preferably set so that the surface temperature of the toner image at the time of fixing is within the above range.

The cooling rate of the toner image in the fixing step (cooling rate of the toner image after fixing and before heat treatment) is not particularly limited, but is preferably 5 ° C./sec or more, and more preferably 50 ° C./sec or more. , 80 ° C./sec or higher is more preferable, and 100 ° C./sec or higher is particularly preferable. Within these ranges, it becomes easier to eliminate the thermal history of the heat-sensitive material before the heat treatment and during the fixing treatment, and it becomes easier to control the image glossiness by the heat treatment. Further, the cooling rate of the toner image in the fixing step can be set to 200 ° C./sec or less in, for example, a general fixing step.

The cooling rate (° C./sec) of the toner image in the fixing step is, for example, the ambient temperature from the surface temperature of the target toner image, or the temperature higher than the minimum temperature after fixing and before the heat treatment (for example, room temperature). From the subtracted value (° C), the surface temperature of the toner image returns to the ambient temperature first from the surface temperature of the target toner image, or the temperature higher than the minimum temperature before heat treatment after fixing (for example, room temperature). It can be calculated by dividing the time (sec) up to. The method for measuring the surface temperature of the toner image is as described above.

The cooling rate of the toner image in the fixing step can be controlled by changing the cooling conditions such as the transport speed of the recording medium and the cooling temperature, for example. Here, if the transport speed is increased, the cooling speed becomes faster, and if the transport speed is lowered, the cooling speed of the toner image in the fixing step becomes slower.

The transport speed of the recording medium in the fixing step is not particularly limited, but is preferably 50 mm / sec or more, more preferably 100 mm / sec or more, and further preferably 150 mm / sec or more. Within these ranges, it becomes easier to eliminate the thermal history of the heat-sensitive material before the heat treatment and during the fixing treatment, and it becomes easier to control the image glossiness by the heat treatment. The transport speed of the recording medium in the fixing step is not particularly limited, but is preferably 600 mm / sec or less, more preferably 550 mm / sec or less, and further preferably 500 mm / sec or less. Within these ranges, it becomes easier to secure time for heat transfer to the media.

(Heat treatment process)
In this step, the toner image fixed on the recording medium is heat-treated.

In the heat treatment step, the glossiness of the toner image is changed by the above image post-processing method.

(Cleaning process)
Further, in addition to the above steps, a cleaning step of removing residual toner on the electrophotographic photosensitive member may be further included.

In this step, the liquid developer that has not been used for image formation or remains untransferred on the developer carrier such as the developing roller, the photoconductor, and the intermediate transfer body is removed from the developer carrier.

The cleaning method is not particularly limited, but a method using a blade provided with the tip in contact with the photoconductor and scraping the surface of the photoconductor is preferable, for example, a cleaning blade and an upstream of the cleaning blade. A brush roller provided on the side can be used.

[Image forming device]
One embodiment of the present invention is an image forming apparatus for forming an electrophotographic image, which includes a fixing image forming apparatus and the above-mentioned image post-processing apparatus. Here, the fixing image forming apparatus includes a developing unit that develops an electrostatic latent image with the above-mentioned electrophotographic toner to form a toner image, a transfer unit that transfers the toner image onto a recording medium, and a transfer unit. It includes a fixing portion for fixing the toner image after being transferred onto the recording medium onto the recording medium by using a fixing member. Further, the fixing portion can be set to a condition that the temperature of the fixing member and the transport speed of the recording medium can make the heat-sensitive material in the electrophotographic toner transparent. Then, the image post-processing apparatus can change the glossiness of the toner image by heat-treating the toner image fixed on the recording medium.

The image forming apparatus according to the embodiment of the present invention is preferably an apparatus used for performing the above-mentioned image forming method.

Hereinafter, an example of an image forming apparatus according to an embodiment of the present invention will be described with reference to the drawings. However, the image forming apparatus according to the present invention is not limited to the apparatus described below.

The image forming apparatus 1 shown in FIG. 3 is referred to as a tandem type color image forming apparatus, and as a fixing image forming apparatus, four sets of image forming units (process cartridges) 10Y, 10M, 10C, and 10Bk, and an endless belt. It is configured to include an intermediate transfer unit 7 in the shape of an intermediate transfer unit 7, a paper feed transfer unit 21, and a fixing unit 24 as a fixing means. A document image reading device SC is arranged on the upper part of the device main body A.

Although FIG. 3 shows an image forming apparatus including four sets of image forming units (process cartridges) 10Y, 10M, 10C, and 10Bk, only the image forming unit 10Bk may be used, or four sets of image forming units may be used. Of the image forming units (process cartridges) 10Y, 10M, 10C, and 10Bk, at least two sets of image forming units may be provided.

The image forming unit 10Y forms a yellow color image. The image forming unit 10Y is configured by arranging a charging unit 2Y, an exposure unit 3Y, a developing unit 4Y as a developing means, and a cleaning unit 6Y around a drum-shaped electrophotographic photosensitive member 1Y. Further has a primary transfer roller 5Y as.

The image forming unit 10M forms a magenta image. The image forming unit 10M is configured by arranging a charging unit 2M, an exposure unit 3M, a developing unit 4M, and a cleaning unit 6M around a drum-shaped electrophotographic photosensitive member 1M, and provides a primary transfer roller 5M as a transfer means. Have more.

The image forming unit 10C forms a cyan image. The image forming unit 10C is configured by arranging a charging unit 2C, an exposure unit 3C, a developing unit 4C, and a cleaning unit 6C around a drum-shaped electrophotographic photosensitive member 1C, and provides a primary transfer roller 5C as a transfer means. Have more.

The image forming unit 10Bk forms a black image. The image forming unit 10Bk is configured by arranging a charging unit 2Bk, an exposure unit 3Bk, a developing unit 4Bk, and a cleaning unit 6Bk around a drum-shaped electrophotographic photosensitive member 1Bk, and provides a primary transfer roller 5Bk as a transfer means. Have more.

The image forming units 10Y, 10M, 10C, and 10Bk are similarly configured except that the colors of the toner images formed on the electrophotographic photosensitive members 1Y, 1M, 1C, and 1Bk are different. Therefore, in the following, the image forming unit 10Y will be described as an example.

In the present embodiment, in the image forming unit 10Y, at least the electrophotographic photosensitive member 1Y, the charging unit 2Y, the developing unit 4Y, and the cleaning unit 6Y are integrated.

The charging unit 2Y applies a uniform potential to the electrophotographic photosensitive member 1Y to charge (for example, negatively charge) the surface of the electrophotographic photosensitive member 1Y (for example, the surface of the protective layer of the electrophotographic photosensitive member). .. The charged portion 2Y may charge the surface of the electrophotographic photosensitive member 1Y by a non-contact charging method, but it is preferable to charge the surface of the electrophotographic photosensitive member 1Y by a contact charging method as described later.

The exposed portion 3Y exposes the surface of the electrophotographic photosensitive member 1Y to which a uniform potential is applied by the charged portion 2Y (for example, the surface of the protective layer of the electrophotographic photosensitive member) based on an image signal (yellow). This forms an electrostatic latent image corresponding to the yellow image. The exposure unit 3Y includes an LED configured by arranging light emitting elements in an array in the axial direction of the electrophotographic photosensitive member 1Y and an imaging element (trade name: Selfock (registered trademark) lens), or an exposure unit 3Y. , Laser optical system and the like can be used.

The developing unit 4Y develops the electrostatic latent image formed by the exposed unit 3Y with an electrostatic latent image developer to form a toner image. The electrostatic latent image developer to be used is not particularly limited, but a dry developer is preferable.

Even if the electrophotographic photosensitive member 1Y, the charging unit 2Y, the exposure unit 3Y, the developing unit 4Y, the cleaning unit 6Y, and the like are integrated as a process cartridge, and the process cartridge is detachably attached to the apparatus main body A. good. Further, at least one of the charging unit 2Y, the exposure unit 3Y, the developing unit 4Y, the transfer or separator, and the cleaning unit 6Y is integrally supported together with the electrophotographic photosensitive member 1Y to form a process cartridge, and the process cartridge is formed. Even if it is configured as a single image forming unit that can be attached to and detached from the device main body A, and the single image forming unit is detachably attached to the device main body A by using a guiding means such as a rail of the device main body A. good.

The housing 8 having the image forming units 10Y, 10M, 10C, and 10Bk and the endless belt-shaped intermediate transfer unit 7 is configured to be retractable from the apparatus main body A by the support rails 82L and 82R. In the housing 8, the image forming units 10Y, 10M, 10C, and 10Bk are arranged in parallel in the vertical direction. The endless belt-shaped intermediate transfer unit 7 is arranged on the left side of the electrophotographic photosensitive members 1Y, 1M, 1C, and 1Bk in FIG. 3, and is rotatable by winding rollers 71, 72, 73, and 74. It has an endless belt-shaped intermediate transfer body 70, a primary transfer roller 5Y, 5M, 5C, 5Bk, and a cleaning portion 6b.

The fixing unit 24 includes a pressure unit that pressurizes the toner image formed on the recording medium P.

The pressurizing section is composed of a fixing roller 92 and a pressurizing roller 93, and when the recording medium P holding the toner image is supplied, the fixing roller 92 and the pressurizing roller 93 transfer the toner image on the recording medium P. Crimping to.

Further, the fixing roller 92 can heat the toner image on the recording medium P when the recording medium P passes between the fixing roller 92 and the pressure roller 93. The toner image is further softened by this heating, and as a result, the fixability of the toner image to the recording medium P is further improved.

It is preferable that the fixing unit 24 can set the temperature of the fixing roller 92 and the transport speed of the recording medium P to conditions that can make the heat-sensitive material in the toner transparent. Further, it is more preferable that the temperatures of the fixing roller 92 and the pressure roller 93 and the transport speed of the recording medium P can be set to conditions that can make the heat-sensitive material in the toner transparent.

The preferred temperature range of the fixing roller 92 is the preferred fixing temperature range in the description of the fixing step of the image forming method described above.

The preferred temperature range of the pressure roller 93 is also the preferred fixing temperature range in the description of the fixing step of the image forming method described above. It is also preferable that the fixing roller 92 and the pressure roller 93 have the same temperature.

Further, the range of the preferable transport speed of the recording medium P in the fixing unit 24 is the range of the transport speed of the recording medium in the preferable fixing step in the description of the fixing step of the image forming method.

The images of each color formed by the image forming units 10Y, 10M, 10C, and 10Bk are sequentially transferred onto the rotating endless belt-shaped intermediate transfer body 70 by the primary transfer rollers 5Y, 5M, 5C, and 5Bk. As a result, a combined color image is formed.

The recording medium P housed in the paper cassette 20 is fed by the paper feed transport unit 21, passes through a plurality of intermediate rollers 22A, 22B, 22C, 22D and a resist roller 23, and is a secondary transfer roller as a transfer means. It is transported to 5b. In the secondary transfer roller 5b, the synthesized color image is secondarily transferred to the recording medium P, and thus the color image is collectively transferred to the recording medium P. When the synthesized color image is secondarily transferred to the recording medium P, the endless belt-shaped intermediate transfer body 70 performs curvature separation of the recording medium P.

In the recording medium P, the toner image is fixed on the recording medium P by the fixing roller 92 and the pressure roller 93 in the fixing portion 24.

Next, in the heat treatment unit 100, the toner image fixed on the recording medium P is heated, and the glossiness of the toner image is lowered or increased.

The image-post-processed recording medium P is sandwiched between the paper ejection rollers 25 and placed on the paper ejection tray 26 outside the machine. On the other hand, the electrostatic latent image developer (residual toner) adhering to the intermediate transfer member 70 is removed by the cleaning unit 6b.

During image formation, the primary transfer roller 5Bk is always in contact with the surface of the electrophotographic photosensitive member 1Bk. On the other hand, the primary transfer rollers 5Y, 5M, and 5C come into contact with the surfaces of the corresponding electrophotographic photosensitive members 1Y, 1M, and 1C only when forming a color image. Further, the secondary transfer roller 5b comes into contact with the surface of the endless belt-shaped intermediate transfer body 70 only when the recording medium P passes through the secondary transfer roller 5b and the secondary transfer is performed.

As described above, the image forming apparatus according to a preferred embodiment of the present invention includes a charging unit, an exposure unit, a developing unit as a developing means, a cleaning unit, a transfer unit, and a fixing unit. Includes forming device. Here, the transfer unit includes a primary transfer roller, an intermediate transfer unit, and a secondary transfer roller.

Further, as described above, the image forming apparatus 1 shown in FIG. 3 includes an image post-processing apparatus including a heat treatment unit 100. In FIG. 3, as the image post-processing apparatus, an apparatus including a heat treatment unit 100 provided with a heatable pressure roller 300, which has the same configuration as that of FIG. 1 except that the transport belt 110 is not provided, is exemplified. However, the heat treatment unit and the image post-processing apparatus used in the image forming apparatus 1 are not limited to this. The image post-processing apparatus used in the image forming apparatus 1 is the same as the description of the image post-processing apparatus described above, and thus the description thereof will be omitted.

This image post-processing device may be, for example, a device that can be removed from the electrophotographic image forming device. As shown in FIG. 3, the heat treatment unit 100 may be provided inside the apparatus main body A, or may be provided outside the apparatus main body A unlike FIG. 3. When the heat treatment unit 100 is provided inside the apparatus main body A, the fixing image forming apparatus and the image post-processing apparatus are present inside the apparatus main body A. Further, when the heat treatment unit 100 is provided outside the apparatus main body A, the apparatus main body A represents the apparatus main body of the fixing image forming apparatus, and separately, an image post-processing apparatus is provided.

Further, it is preferable to provide a glossiness detection unit (not shown) between the fixing unit 24 and the heat treatment unit 100 to detect the glossiness. As a result, the glossiness of the toner image before the heat treatment can be measured. Therefore, after the user confirms the measured glossiness value, whether the glossiness is lower or higher than the glossiness detected by the heat treatment unit 100. Etc. can be selected.

It is also preferable to provide a glossiness detection unit (not shown) after the heat treatment unit 100. This makes it possible to confirm whether the heat treatment unit 100 has been able to adjust the glossiness to a desired level. Further, the glossiness may be adjusted again by the heat treatment unit 100 after the glossiness is measured by the glossiness detection unit.

The effects of the present invention will be described with reference to the following examples and comparative examples. However, the technical scope of the present invention is not limited to the following examples.

<< Toner preparation >>
<Preparation of heat-sensitive material particle dispersion>
[Polymer LCD compound-containing particle dispersion (A)]
(Synthesis of Polymer Liquid Crystal Compound (A1))
285 parts by mass of 4-acryloxyhexyloxy-4'-cyano-biphenyl as a mesogen monomer, 15 parts by mass of butyl methacrylate as a non-mesogen monomer, 0.6 parts by mass of AIBN (azoisobutynitrile) as a polymerization initiator, and a solvent. Using 300 parts by mass of MEK (methyl ethyl ketone), copolymerize at 70 ° C. for 24 hours, reprecipitate and purify in methanol to obtain 290 parts by mass of the polymer liquid crystal compound (A1) represented by the following structural formula (I). Obtained. The weight average molecular weight of the polymer liquid crystal compound (A1) measured by GPC (gel permeation chromatography) using polystyrene as a standard substance was 120,000. Moreover, when measured by DSC (differential calorimetry), the glass transition point of the polymer liquid crystal compound (A1) was higher than room temperature (25 ° C.).

(Preparation of Particle Dispersion Solution (A) Containing Polymer Liquid Crystal Compound)
A solution was obtained by dissolving 200 parts by mass of the polymer liquid crystal compound (A1) obtained above in 200 parts by mass of ethyl acetate heated to 70 ° C. The obtained solution and an aqueous solution in which 800 parts by mass of ion-exchanged water is dissolved with sodium polyoxyethylene lauryl ether sulfate at a concentration of 1% by mass are mixed and dispersed using an ultrasonic homogenizer to obtain an emulsion. rice field. 1200 parts by mass of the obtained emulsion was placed in a 2 liter eggplant flask and set in an evaporator (Tokyo Rika Kikai Co., Ltd.) equipped with a vacuum control unit via a trap ball. Next, while rotating the eggplant flask, the mixture was heated in a water bath at 60 ° C. and reduced to 7 kPa while paying attention to bumping to remove the solvent. Then, when the amount of solvent recovered reached 400 parts by mass, the pressure was returned to normal pressure, and the eggplant flask was water-cooled to obtain a dispersion liquid. Ion-exchanged water was added to the obtained dispersion to adjust the solid content concentration (representing the concentration of the polymer liquid crystal compound (A1)) to 20% by mass. As a result, a polymer liquid crystal compound-containing particle dispersion liquid (A) in which particles of the polymer liquid crystal compound (A1) were dispersed in an aqueous medium was prepared. The volume-based median diameter of the above particles measured by the dynamic light scattering method using "Microtrack UPA-150" (manufactured by Nikkiso Co., Ltd.) was 210 nm.

[Polymer LCD compound-containing particle dispersion (B)]
(Preparation of polymer liquid crystal compound (B1))
A polymer liquid crystal compound (B1) represented by the following structural formula (II) described in paragraph 0025 of JP-A-7-304265 was prepared. The weight average molecular weight of the polymer liquid crystal compound (B1) measured by GPC (gel permeation chromatography) using polystyrene as a standard substance was 100,000. Moreover, when measured by DSC (differential calorimetry), the glass transition point of the polymer liquid crystal compound (B1) was higher than room temperature (25 ° C.).

(Preparation of Particle Dispersion Liquid (B) Containing Polymer Liquid Crystal Compound)
150 parts by mass of the above high molecular weight liquid crystal compound (B1) and 50 parts by mass of behenic acid (melting point 80 ° C.), which is a low molecular weight compound, are dissolved in 200 parts by mass of ethyl acetate heated to 70 ° C. A solution was obtained. The obtained solution and an aqueous solution in which 800 parts by mass of ion-exchanged water is dissolved with sodium polyoxyethylene lauryl ether sulfate at a concentration of 1% by mass are mixed and dispersed using an ultrasonic homogenizer to obtain an emulsion. rice field. 1200 parts by mass of the obtained emulsion was placed in a 2 liter eggplant flask and set in an evaporator (Tokyo Rika Kikai Co., Ltd.) equipped with a vacuum control unit via a trap ball. Next, while rotating the eggplant flask, the mixture was heated in a water bath at 60 ° C. and reduced to 7 kPa while paying attention to bumping to remove the solvent. Then, when the amount of solvent recovered reached 400 parts by mass, the pressure was returned to normal pressure, and the eggplant flask was water-cooled to obtain a dispersion liquid. Ion-exchanged water was added to the obtained dispersion to adjust the solid content concentration (representing the total concentration of the polymer liquid crystal compound (B1) and behenic acid) to 20% by mass. As a result, a particle dispersion liquid (B) in which particles of the polymer liquid crystal compound (B1) were dispersed in an aqueous medium was prepared. The volume-based median diameter of the above particles measured by a dynamic light scattering method using "Microtrack UPA-150" (manufactured by Nikkiso Co., Ltd.) was 210 nm.

<Preparation of binder resin dispersion>
[Crystalline polyester resin particle dispersion liquid (C)]
(Synthesis of crystalline polyester resin (C1))
The raw material monomer and radical polymerization initiator of the following addition polymerization resin (styrene-acrylic resin: StAc) segment containing both reactive monomers were placed in a dropping funnel.

34 parts by mass of styrene
n-Butyl acrylate 12 parts by mass
2 parts by mass of acrylic acid
Polymerization initiator (di-t-butyl peroxide) 7 parts by mass In addition, the raw material monomer of the following polycondensation resin (crystalline polyester resin: CPEs) segment is used in a nitrogen introduction tube, dehydration tube, stirrer and thermocouple. It was placed in a equipped four-necked flask and heated to 170 ° C. to dissolve it.

281 parts by mass of sebacic acid
283 parts by mass of 1,12-dodecanediol Next, the raw material monomer of the addition polymerization resin (StAc) placed in the dropping funnel under stirring was dropped into the four-necked flask over 90 minutes, and aged for 60 minutes. After that, the unreacted addition polymerization monomer was removed under reduced pressure (8 kPa). The amount of the monomer removed at this time was a very small amount with respect to the ratio of the raw material monomers of the above resin.

Then, 0.8 parts by mass of Ti (OBu) ₄ was added as an esterification catalyst, the temperature was raised to 235 ° C., and the reaction was carried out under normal pressure (101.3 kPa) for 5 hours and further under reduced pressure (8 kPa) for 1 hour. gone.

Next, after cooling to 200 ° C., the reaction was carried out under reduced pressure (20 kPa) for 1 hour to obtain a crystalline polyester resin (C1) which is a hybrid crystalline polyester resin. The crystalline polyester resin (C1) contained 8% by mass of a resin (StAc) segment other than CPEs with respect to the total amount thereof, and was a resin in which CPEs were grafted to StAc. The number average molecular weight (Mn) of the crystalline polyester resin (C1) measured by GPC (gel permeation chromatography) using polystyrene as a standard material is 9,000, and it is measured by a differential calorimetry device (DSC). The measured melting point (Tc) of the crystalline polyester resin (C1) was 75 ° C.

(Preparation of crystalline resin particle dispersion liquid (C))
30 parts by mass of the crystalline polyester resin (C1) obtained above is melted, and the transfer rate is 100 parts by mass per minute with respect to the emulsification disperser "Cavitron CD1010" (manufactured by Eurotec Ltd.) in the molten state. Transferred at. At the same time as the transfer of the crystalline polyester resin (C1) in the molten state, 70 parts by mass of the reagent ammonia water is ion-exchanged with the emulsion disperser "Cavitron CD1010" (manufactured by Eurotec Ltd.) in an aqueous solvent tank. Dilute aqueous ammonia having a concentration of 0.37% by mass diluted with water was transferred at a transfer rate of 0.1 liter per minute while heating to 100 ° C. with a heat exchanger. Then, by operating this emulsifying disperser "Cavitron CD1010" (manufactured by Eurotec Ltd.) under ^{the conditions of a rotor rotation speed of 60 Hz and a pressure of 5 kg / cm 2} , the solid content (crystalline polyester resin (C1)) can be determined. A crystalline resin particle dispersion (C) having an amount of 30 parts by mass was prepared. The volume-based median diameter of the crystalline resin particles in the crystalline resin particle dispersion liquid (C) subjected to dynamic light scattering using "Microtrac UPA-150" (manufactured by Nikkiso Co., Ltd.) was 200 nm. ..

[Amorphous resin particle dispersion liquid (X-1)]
(1) First-stage polymerization In a 5 L reaction vessel equipped with a stirrer, temperature sensor, condenser and nitrogen introduction device, 8 parts by mass of sodium dodecyl sulfate and 3000 parts by mass of ion-exchanged water are charged and stirred at 230 rpm under a nitrogen stream. The internal temperature was raised to 80 ° C. while stirring at a rate. After raising the temperature, 10 parts by mass of potassium persulfate dissolved in 200 parts by mass of ion-exchanged water was added, the liquid temperature was adjusted to 80 ° C. again, and a monomer mixed solution having the following composition was added dropwise over 1 hour. Polymerization was carried out by heating and stirring at 80 ° C. for 2 hours to prepare a dispersion liquid (x1) of resin particles.

480 parts by mass of styrene
250 parts by mass of n-butyl acrylate
68 mass of methacrylic acid (2) Second-stage polymerization In a 5 L reaction vessel equipped with a stirrer, temperature sensor, cooling tube and nitrogen introduction device, 7 parts by mass of polyoxyethylene (2) dodecyl ether sodium sulfate was added to 3000 parts of ion-exchanged water. A solution prepared by dissolving in parts by mass was charged and heated to 98 ° C., and then 260 parts by mass of a dispersion liquid (x1) of resin particles and a solution in which a monomer having the following composition and a mold release agent were dissolved at 90 ° C. Was mixed and dispersed for 1 hour with a mechanical disperser "CLEARMIX" (manufactured by M-Technique Co., Ltd.) having a circulation path to prepare a dispersion containing emulsified particles (oil droplets).

284 parts by mass of styrene (St)
n-Butyl acrylate (BA) 92 parts by mass
Methacrylic acid (MAA) 13 parts by mass
n-octyl-3-mercaptopropionate 1.5 parts by mass
Mold release agent: behenyl behenate (melting point 73 ° C.) 190 parts by mass Then, to this dispersion, an initiator solution in which 6 parts by mass of potassium persulfate was dissolved in 200 parts by mass of ion-exchanged water was added, and this system was mixed with 84 parts. Polymerization was carried out by heating and stirring at ° C. for 1 hour to prepare a dispersion liquid (x2) of resin particles. (3) Third-stage polymerization Add 400 parts by mass of ion-exchanged water to the dispersion liquid (x2) of resin particles. After mixing, a solution prepared by dissolving 11 parts by mass of potassium persulfate in 400 parts by mass of ion-exchanged water was added, and a monomer mixed solution having the following composition was added under a temperature condition of 82 ° C. over 1 hour. Dropped. After the completion of the dropping, the polymerization was carried out by heating and stirring for 2 hours, then cooled to 28 ° C., and the amorphous resin particle dispersion liquid (X-) containing a vinyl resin (styrene-acrylic resin 1) as the amorphous resin was added. 1) was prepared.

Styrene (St) 350 parts by mass
n-Butyl acrylate (BA) 215 parts by mass
Acrylic acid (AA) 30 parts by mass
n-octyl-3-mercaptopropionate 8 parts by mass When the physical properties of the obtained amorphous resin particle dispersion (X-1) were measured, the glass transition point (Tg) measured by a differential calorimetry device (DSC) was measured. ) Was 55 ° C., and the weight average molecular weight (Mw) measured by GPC (gel permeation chromatography) using polystyrene as a standard substance was 32,000. Further, the volume-based median diameter of the amorphous resin particles in the amorphous resin particle dispersion liquid (X-1) subjected to the dynamic light scattering method using "Microtrac UPA-150" (manufactured by Nikkiso Co., Ltd.) is It was 220 nm.

[Amorphous resin particle dispersion liquid (X-2)]
In the preparation of the above-mentioned amorphous resin particle dispersion liquid (X-1), the monomer mixed solution used in the first-stage polymerization, the monomer used in the second-stage polymerization, and the release agent were prepared at 90 ° C. The composition of the dissolved solution and the monomer mixed solution used in the third-stage polymerization were changed in the same manner as shown in Table 1 below, respectively, and the vinyl resin (styrene-acrylic resin 2) was used as the amorphous resin. ) Was prepared as an amorphous resin particle dispersion (X-2).

When the physical properties of the obtained amorphous resin particle dispersion (X-2) were measured, the glass transition point (Tg) measured by a differential calorimetry device (DSC) was 45 ° C., GPC (gel permeation chromatography). The weight average molecular weight (Mw) measured using polystyrene as a standard substance was 33,000. Further, the volume-based median diameter of the amorphous resin particles in the amorphous resin particle dispersion liquid (X-2) subjected to the dynamic light scattering method using "Microtrac UPA-150" (manufactured by Nikkiso Co., Ltd.) is It was 210 nm.

<Preparation of colorant particle dispersion>
90 parts by mass of sodium dodecyl sulfate is stirred and dissolved in 1600 parts by mass of ion-exchanged water, and while stirring this solution, 420 parts by mass of carbon black "Legal (registered trademark) 330R" (manufactured by Cabot Corporation), which is a pigment, is gradually added. did. Next, a colorant particle dispersion (Bk) in which black colorant particles were dispersed was prepared by dispersion treatment using a stirrer "Clairemix" (manufactured by M-Technique Co., Ltd.). The volume-based median diameter of the colorant particles in the colorant particle dispersion (Bk) measured using "ELSZ-1000" (manufactured by Otsuka Electronics Co., Ltd.) was 120 nm.

<Manufacturing of toner and developer>
[Manufacturing of toner]
(Manufacturing of toner 1)
After adding 185 parts by mass (solid content equivalent) of amorphous resin particle dispersion (X-1) and 2000 parts by mass of ion-exchanged water to a reaction vessel equipped with a stirrer, temperature sensor, and cooling tube, 5 mol / mol / The pH was adjusted to 10 by adding liters of aqueous sodium hydroxide solution.

40 parts by mass (in terms of solid content) of the colorant particle dispersion liquid (Bk) and 10 parts by mass of the polymer liquid crystal compound-containing particle dispersion liquid (A) in the amorphous resin particle dispersion liquid (X-1) after adjusting the pH. Parts (in terms of solid content) were added. Next, an aqueous solution prepared by dissolving 30 parts by mass of magnesium chloride as a flocculant in 60 parts by mass of ion-exchanged water was added at 30 ° C. over 10 minutes with stirring. The temperature of this mixed solution is started, the temperature is raised to 60 ° C. at a heating rate of 0.8 ° C./min, and 20 parts by mass (solid fraction) of the crystalline resin particle dispersion liquid (C) is applied over 10 minutes. After the addition, the temperature was further raised to 80 ° C. at a heating rate of 0.8 ° C./min. Aggregation proceeded while maintaining the temperature of 80 ° C., and the particle size of the associated particles was measured with "Coulter Multisizer 3" (manufactured by Beckman Coulter Co., Ltd.), and the mass-based median size became 6.0 μm. At this point, an aqueous solution prepared by dissolving 190 parts by mass of sodium chloride in 760 parts by mass of ion-exchanged water was added to stop particle growth. Further, the particles are fused by heating and stirring at 80 ° C., and the average circularity of the toner is measured using the measuring device "FPIA-2100" (manufactured by Sysmex) (HPF detection number is 4000). When the average circularity reached 0.945, the mixture was cooled to 30 ° C. at a cooling rate of 2.5 ° C./min.

The volume-based median diameter of the aggregates in the mixed liquid at the time of adding the crystalline resin particle dispersion liquid (C) was 0.80 μm. The volume-based median diameter was obtained by measuring the volume average particle diameter with UPA-150 (manufactured by Microtrac).

Next, the operation of solid-liquid separation, redispersion of the dehydrated toner cake in ion-exchanged water, and solid-liquid separation was repeated three times for washing, and then dried at 40 ° C. for 24 hours to obtain toner matrix particles.

In 100 parts by mass of the obtained toner base particles, 0.6 parts by mass of hydrophobic silica (number average primary particle diameter = 12 nm, degree of hydrophobicity = 68) and hydrophobic titanium oxide (number average primary particle diameter = 20 nm, hydrophobicization). Degree = 63) Add 1.0 part by mass, mix these with a "Henshell mixer (registered trademark)" (manufactured by Nippon Coke Industries Co., Ltd.) at a rotary blade peripheral speed of 35 mm / sec and 32 ° C for 20 minutes, and then 45 μm. Coarse particles were removed using a flue with an opening. By performing such an external additive treatment, a toner 1 for electrophotographic (for electrostatic latent image development) 1 was manufactured.

In the production of the toner 1, the "mass portion (in terms of solid content)" of the amount of each dispersion added is the polymer liquid crystal which is a heat-sensitive material in the polymer liquid crystal compound-containing particle dispersion (A). Represents an amount containing the sex compound (A1) as a mass portion thereof. Further, the crystalline resin particle dispersion liquid (C) represents an amount containing the crystalline polyester resin (C1) as a mass portion thereof. Further, in the amorphous resin particle dispersion liquid (X-1), the total amount of the mass part of the styrene-acrylic resin 1 and the mass part of the release agent (behenyl behenate) is represented as the mass part thereof. The colorant particle dispersion liquid (Bk) represents the amount of the pigment (carbon black) contained in the dispersion liquid as a mass portion thereof.

(Manufacturing of toners 2 to 5)
The same applies to the production of the toner 1 except that the types and amounts of the heat-sensitive material particle dispersion, the crystalline resin particle dispersion, the amorphous resin particle dispersion, and the colorant particle dispersion are changed as shown in Table 2 below. Toners 2 to 5 for electrophotographic (electrostatic latent image development) were manufactured.

The "mass part (in terms of solid content)" of the amount of each dispersion added is the mass part of the styrene-acrylic resin 2 and the release agent (Behen) in the amorphous resin particle dispersion (X-2). Represents the amount including the sum of the mass parts of (behenyl acid) as the mass part. Further, in the polymer liquid crystal compound-containing particle dispersion liquid (B), the sum of the mass parts of the polymer liquid crystal compound (B1) which is a heat-sensitive material and the mass part of the low molecular weight compound (bechenic acid) which is a heat-sensitive material is the sum. Represents the amount contained as a mass part. The other dispersions are the same as those described in the production of the toner 1.

[Manufacturing of developers 1 to 5]
For the electrophotographic toners 1 to 5 obtained above, a ferrite carrier having a volume average particle diameter of 30 μm coated with a copolymer resin of cyclohexyl methacrylate and methyl methacrylate (monomer mass ratio = 1: 1) was used, and the toner concentration was high. Developers 1 to 5 were produced by mixing them so as to be 6% by mass. Mixing was carried out for 30 minutes using a V-type mixer.

It should be noted that the number of the toner for electrophotographic and the number of the developer correspond to each other, and for example, the developer manufactured by using the toner 1 for electrophotographic is referred to as the developer 1.

<< Evaluation >>
<Evaluation of thermal materials>
[Confirmation of changes in light scattering properties of particles in the heat-sensitive material particle dispersion]
When the haze value measured according to JIS K 7136: 2000 using a haze meter (model NDH 2000, manufactured by Nippon Denshoku Co., Ltd.) is in the following range, the measurement sample is in a transparent state, a translucent state, and an opaque state, respectively. Judge as:
Transparent state: Haze value is 10% or less,
Translucent state: Haze value is over 10%, less than 80%,
Opaque state: Haze value is 80% or more.

In addition, each haze value in the following measurement is also a value measured by using this method.

(The heat-sensitive material in the polymer liquid crystal compound-containing particle dispersion liquid (A))
A resin solution was prepared by dissolving 5 parts by mass of the polymer liquid crystal compound (A1) obtained above in 15 parts by mass of tetrahydrofuran. Then, a coating was applied on a 100 μm transparent PET film with a bar coater, and the coating film was dried to obtain a 15 μm film. When the haze value was measured for the initial state of the film (that is, the state left at room temperature after the film was manufactured), the haze value was 42%, and the film was in a translucent state. It was also confirmed visually that the appearance was slightly cloudy.

The obtained film was heated in a heating furnace at 120 ° C. for 10 minutes, then immediately taken out at room temperature (25 ° C.) and rapidly cooled to room temperature (25 ° C.) (film cooling rate of 5 ° C./sec or higher). When the haze value was measured for this state of the film, the haze value was 7%, and the film was in a transparent state. It was also confirmed visually that there was almost no cloudiness in the appearance.

Further, the obtained film was heated in a heating furnace at 120 ° C. for 10 minutes, and then the temperature of the heating furnace was gradually lowered to room temperature (25 ° C.) (slow cooling operation, film cooling rate of 1 ° C./sec or less). .. When the haze value was measured for this state of the film, the haze value was 85%, and the film was in an opaque state (white turbid state). It was also confirmed visually that the appearance was cloudy.

When the heated state of the obtained film was visually confirmed by heating at 120 ° C. for 10 minutes, the white turbidity in appearance was almost the same as that in the transparent state described above, and was hardly confirmed.

From these results, it was confirmed that the haze value of the polymer liquid crystal compound (A1) changed by at least about 78% depending on the heating temperature or the cooling rate, and the degree of white turbidity clearly changed visually. From this, it was confirmed that the polymer liquid crystal compound (A1) is a material whose light scattering property changes depending on the heating temperature and the cooling rate.

(The heat-sensitive material in the polymer liquid crystal compound-containing particle dispersion liquid (B))
A resin solution was prepared by dissolving 6 parts by mass of the above-mentioned polymer liquid crystal compound (B1) and 2 parts by mass of behenic acid in 20 parts by mass of tetrahydrofuran. Then, a coating was applied on a 100 μm transparent PET film with a bar coater, and the coating film was dried to obtain a 15 μm film. When the haze value was measured for the initial state of the film (that is, the state left at room temperature after the film was manufactured), the haze value was 46%, and the film was in a translucent state. It was also confirmed visually that it was slightly cloudy.

The obtained film was heated in a heating furnace at 120 ° C. for 10 minutes, then immediately taken out at room temperature (25 ° C.) and rapidly cooled to room temperature (25 ° C.) (film cooling rate of 5 ° C./sec or higher). When the haze value was measured for this state of the film, the haze value was 6%, and the film was in a transparent state. It was also confirmed visually that there was almost no cloudiness in the appearance.

Further, the obtained film was heated in a heating furnace at 120 ° C. for 10 minutes, and then the temperature of the heating furnace was gradually lowered to room temperature (25 ° C.) (slow cooling operation, film cooling rate of 1 ° C./sec or less). .. When the haze value was measured for this state of the film, the haze value was 90%, and the film was in an opaque state (white turbid state). It was also confirmed visually that the appearance was cloudy.

When the heated state of the obtained film was visually confirmed by heating at 120 ° C. for 10 minutes, the white turbidity in appearance was almost the same as that in the transparent state described above, and was hardly confirmed.

From these results, it was confirmed that the haze value of the mixture of the polymer liquid crystal compound (B1) and behenic acid changed by at least about 84% depending on the heating temperature or the cooling rate, and the degree of white turbidity clearly changed visually. Was done. From this, it was confirmed that the mixture of the polymer liquid crystal compound (B1) and behenic acid is a material whose light scattering property changes depending on the heating temperature and the cooling rate.

<Evaluation of toner>
[Preparation of image forming apparatus used for evaluation]
(Preparation of evaluation machine 1)
As a fixing image forming apparatus, "bizhub PRESS (registered trademark) C1080" manufactured by Konica Minolta Co., Ltd., which is an electrophotographic image forming apparatus, was prepared. The fixing image forming apparatus includes a charging unit, an exposure unit, a developing unit as a developing means, a cleaning unit, a transfer unit, and a fixing unit. Separately from this, an image post-processing apparatus provided with the heat treatment unit 100 shown in FIG. 1 was prepared. As shown in FIG. 1, the heat treatment unit 100 is composed of a set of heatable pressure rollers 300. The image forming apparatus including these fixing image forming apparatus and the image post-processing apparatus was designated as the evaluation machine 1.

(Preparation of evaluation machine 2)
As a fixing image forming apparatus, "bizhub PRESS (registered trademark) C1080" manufactured by Konica Minolta Co., Ltd., which is an electrophotographic image forming apparatus, was prepared. The fixing image forming apparatus includes a charging unit, an exposure unit, a developing unit as a developing means, a cleaning unit, a transfer unit, and a fixing unit. Separately from this, an image post-processing apparatus provided with the heat treatment unit 100 shown in FIG. 2 was prepared. As shown in FIG. 2, the heat treatment unit 100 includes a heater 101A as a non-contact heating unit and a control unit 102. Further, as the heater 101A as the non-contact heating unit, a heater in which a carbon heater was installed as a heat source in the heat insulating cover was used. The image forming apparatus including these fixing image forming apparatus and the image post-processing apparatus was designated as the evaluation machine 2.

[Image gloss]
For each of the developers 1 to 5 obtained above, the developer was set in the fixing image forming apparatus of the evaluation machine, and these were used on A3 coated paper (basis weight: 128 g / m ² ) as a recording medium. A solid toner image was fixed on a recording medium to obtain a fixed image. Here, for fixing, the temperature of the fixing roller (fixing member) is set so that the surface temperature of the toner image at the time of fixing becomes 120 ° C. as a condition for making the particles in the heat-sensitive material particle dispersion liquid transparent, and at the time of fixing. The transport speed was set to 200 mm / sec, and the cooling rate from the heating temperature to room temperature (25 ° C.) after fixing was set to 5 ° C./sec or more.

The cooling rate (° C./sec) of the toner image in the fixing step is the higher of the ambient temperature or the minimum temperature after fixing and before heat treatment (room temperature (room temperature (room temperature)) from the surface temperature (120 ° C.) of the target toner image. From the value (° C) obtained by subtracting 25 ° C)), the surface temperature of the toner image is the ambient temperature first from the surface temperature (120 ° C) of the target toner image, or the one with the higher minimum temperature after fixing and before heat treatment. It was calculated by dividing the time (sec) until the temperature returned to (room temperature (25 ° C.)).

Next, the obtained fixed image was heat-treated using the image post-processing device of the evaluation machine to obtain an image. Here, when the heat treatment is performed with the heated pressure roller, the pressure is set to be 50 kPa.

The cooling rate (° C./sec) of the toner image during heat treatment is, for example, the target toner from the value (° C.) obtained by subtracting the ambient temperature (room temperature (25 ° C.)) from the surface temperature of the target toner image. It was calculated by dividing the time (sec) from the surface temperature of the image until the surface temperature of the toner image first returned to the ambient temperature (room temperature (25 ° C.)).

Each temperature is the surface temperature of the toner image on the recording medium. The surface temperature (° C.) of the toner image was measured using a temperature measuring device (trade name: FT-H10, manufactured by KEYENCE CORPORATION).

Subsequently, for the toner images on the recording medium before and after the image post-processing, one point each 50 mm from the image center point and the image center to the short axis direction of the recording medium, for a total of three points, the incident angle is 60 °. The glossiness (%) was measured, and the average value was taken as the glossiness (%). The glossiness (%) was measured using a glossiness measuring device (MULTI GROSS 268 Plus manufactured by Konica Minolta Co., Ltd.).

Table 3 below shows the evaluation results of the image glossiness according to the combination of the developer and the evaluation machine and the heat treatment conditions.

[Heat-resistant storage of toner]
For each of the electrophotographic toners 1 to 5 obtained above, take 0.5 g of the electrophotographic toner in a 10 ml glass bottle having an inner diameter of 21 mm, close the lid, and use a tap denser (KYT-2000; Seishin Enterprise Co., Ltd.) at room temperature. After shaking 600 times at 57.5 ° C. and 35% RH for 2 hours with the lid removed. Next, place the electrophotographic toner on a sieve of 48 mesh (opening 350 μm), being careful not to crush the agglomerates of the electrophotographic toner, set it on a powder tester (Hosokawa Micron Co., Ltd.), and press it down. It was fixed with a bar and a knob nut, adjusted to a vibration intensity of 1 mm in feed width, vibrated for 10 seconds, and then the ratio (% by mass) of the amount of residual electrophotographic toner on the sieve was measured. The aggregation rate (toner aggregation rate) of the electrophotographic toner is a value calculated by the following formula.

Using the value of the toner aggregation rate, the heat-resistant storage property of the electrophotographic toner was evaluated according to the following criteria, and used as an index of storage stability.

A: Toner aggregation rate is less than 35% by mass (heat resistant storage of electrophotographic toner is good),
B: Toner aggregation rate is 35% by mass or more and less than 50% by mass (heat-resistant storage property of electrophotographic toner is slightly inferior, but acceptable level).
C: Toner aggregation rate is 50% by mass or more (the heat-resistant storage property of the electrophotographic toner is poor and cannot be used).

The evaluation results of the heat-resistant storage property of the electrophotographic toner are shown in Table 3 below.

From the results in Table 1 above, an electrograph containing a binder resin according to an embodiment of the present invention, a pigment as a colorant, and a heat-sensitive material whose light scattering property changes depending on at least one of a heating temperature and a cooling rate. It was confirmed that the image glossiness can be controlled by using the toner for use. It was also confirmed that the toner according to the present invention has excellent heat-resistant storage properties.

On the other hand, the electrophotographic toner according to the comparative example could not control the gloss of the obtained image.

Further, from the results in Table 1 above, the electrophotographic toner according to the embodiment of the present invention is a contact heater that is non-contact heating even in a heat treatment method using a heated pressure rotor that is contact heating. It was confirmed that the image glossiness can be controlled even by the heat treatment method used. From this, it was confirmed that the electrophotographic toner according to the embodiment of the present invention has a high degree of freedom in selecting the applied image forming method and image forming apparatus.

1 Image forming device 7 Intermediate transfer unit 8 Housing 20 Paper cassette 21 Paper transfer section 22A, 22B, 22C, 22D Intermediate roller 23 Resist roller 24 Fixing section 25 Paper ejection roller 26 Paper ejection tray 70 Intermediate transfer unit 71, 72, 73, 74 Roller 92 Fixing roller 93 Pressurizing roller A Device body 5b Secondary transfer roller 6b Cleaning section 82L, 82R Support rail P Recording medium SC Original image reader 1Y, 1M, 1C, 1Bk Electrophotographic photosensitive member 2Y, 2M, 2C, 2Bk Charging unit 3Y, 3M, 3C, 3Bk Exposure unit 4Y, 4M, 4C, 4Bk Development unit 5Y, 5M, 5C, 5Bk Primary transfer roller 6Y, 6M, 6C, 6Bk Cleaning unit 10Y, 10M, 10C 10Bk Image forming unit 100 Heat treatment unit 101A Heater 101a Infrared 102 Control unit 103 Temperature detection unit 110 Conveyance belt 121 Toner image 300 Heatable pressurizing roller

Claims (14)

An electrophotographic toner containing a binder resin, a colorant, and a heat-sensitive material whose light scattering property changes depending on at least one of a heating temperature and a cooling rate. The electrophotographic toner according to claim 1, wherein the heat-sensitive material contains a liquid crystal compound. The electrophotographic toner according to claim 2, wherein the liquid crystal compound is a polymer liquid crystal compound. The electrophotographic toner according to claim 3, further comprising a low molecular weight compound. The electrophotographic toner according to any one of claims 1 to 4, wherein the binder resin contains an amorphous resin, and the glass transition point of the amorphous resin is 45 ° C. or higher. The fourth aspect of claim 4, wherein the binder resin contains an amorphous resin, the glass transition point of the amorphous resin is 45 ° C. or higher, and the melting point of the low molecular weight compound is 60 ° C. or higher and 90 ° C. or lower. Electrophotographic toner. An image post-processing method comprising changing the glossiness of the toner image by heat-treating the toner image formed from the toner according to any one of claims 1 to 6 on a recording medium. The image post-processing method according to claim 7, wherein the heat treatment is performed by an apparatus capable of controlling at least one of a heating temperature and a cooling rate. The image post-processing according to claim 8, wherein the apparatus includes a pressure roller as a heating member, and the heat treatment comprises contacting the heated pressure roller with the toner image on the recording medium. Method. A developing step of developing an electrostatic latent image with the toner according to any one of claims 1 to 6 to form a toner image.
A transfer step of transferring the toner image onto a recording medium, and
After the transfer step, a fixing step of fixing the toner image transferred onto the recording medium onto the recording medium using a fixing member, and a fixing step.
A heat treatment step of heat-treating the toner image fixed on the recording medium, and
Including
In the fixing step, the temperature of the fixing member and the transport speed of the recording medium are set under conditions that can make the heat-sensitive material in the toner transparent.
In the heat treatment step, the glossiness of the toner image is changed by heat-treating the toner image fixed on the recording medium by the image post-processing method according to any one of claims 7 to 9.
Image formation method. Post-image processing capable of changing the glossiness of the toner image by heat-treating the toner image formed from the toner according to any one of claims 1 to 6 on a recording medium. Device. The image post-processing apparatus according to claim 11, wherein at least one of a heating temperature and a cooling time can be controlled. The image post-processing apparatus according to claim 12, wherein the heated pressure roller is brought into contact with the toner image on the recording medium. A developing unit that develops an electrostatic latent image with the toner according to any one of claims 1 to 6 to form a toner image, and a developing unit.
A transfer unit that transfers the toner image onto a recording medium,
A fixing unit that fixes the toner image after being transferred onto the recording medium by the transfer unit onto the recording medium using a fixing member, and a fixing unit.
Including, fixing image forming apparatus, and
The image post-processing apparatus according to any one of claims 11 to 13.
Including
In the fixing portion, the temperature of the fixing member and the transport speed of the recording medium can be set under conditions that can make the heat-sensitive material in the toner transparent.
The image post-processing apparatus can change the glossiness of the toner image by heat-treating the toner image fixed on the recording medium.
Image forming device.

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