JP7524687B2 - Mixed toner, developer, toner storage unit, image forming apparatus, and image forming method - Google Patents

Description

The present invention relates to a mixed toner, a developer, a toner storage unit, an image forming apparatus, and an image forming method.

As electrophotographic color image forming devices become more widespread, the uses of printed matter are becoming more diverse. For example, there is a demand for the ability to stably print toner on substrates with uneven surfaces, such as clothing and other fabric products.

As a method for stably printing toner on such a substrate having an uneven surface, for example, a method has been proposed in which a toner layer is formed on the surface of the print image using a toner for thermal transfer print sheets that contains a negatively charged crystalline polyester resin and has an average particle size D50 in the range of 20 to 50 μm, and the print image is adhered to the transfer medium via the toner layer (see, for example, Patent Document 1).

However, in the technology of Patent Document 1, the toner layer is formed from one type of toner for thermal transfer print sheets, so the toner layer cannot be stably fixed to adherends that have uneven surfaces and are prone to deformation, such as fabric products, and there is a possibility that the print image formed on the adherend substrate via the toner layer may peel off or crack. Therefore, the technology of Patent Document 1 has problems such as impaired color development of the image and insufficient abrasion resistance of the image.

One aspect of the present invention aims to provide a mixed toner that can form images with excellent color development and abrasion resistance.

A toner according to one embodiment of the present invention is a mixed toner used for a concealing layer formed on a substrate having an uneven surface, and contains two types of toners for the concealing layer having different viscoelasticity, wherein the storage modulus G' of one toner for the first concealing layer at 150°C to 190°C is 1.0 x ¹⁰¹ Pa to 1.0 x ¹⁰⁴ Pa , and the storage modulus G' of the other toner for the second concealing layer at 150°C to 190°C is 1.0 x ¹⁰⁵ Pa to 1.0 x ¹⁰⁷ Pa .

According to one aspect of the present invention, a mixed toner can be provided that can form images with excellent color development and abrasion resistance.

FIG. 4 is a diagram showing a state in which a chromatic toner image has been transferred onto a release paper. FIG. 2 is a diagram showing a state in which an image layer is formed on a release paper. FIG. 13 is a diagram showing a state in which a toner image has been transferred onto a chromatic toner image. FIG. 2 is a diagram showing a state in which a concealing layer is formed on an image layer. FIG. 13 is a diagram showing a state in which two concealing layers are formed. FIG. 2 is a diagram showing a state in which a concealing layer is laminated on a substrate having projections and recesses. FIG. 2 is a diagram showing an example of a state in which a release paper and a substrate having projections and recesses are heat-pressed by a heat press machine. FIG. 2 is a diagram showing the state after the release paper and the substrate having projections and recesses are heat-pressed. FIG. 2 is a diagram showing the state in which the release paper is peeled off from the concealing layer. FIG. 2 is a diagram showing an image layer forming area formed on a release paper in Example 1. FIG. 2 is a diagram showing a concealing layer region formed on an image layer forming region in Example 1. FIG. 13 is a diagram showing an example of a contamination gray scale.

The following describes in detail the embodiments of the present invention. Note that the embodiments are not limited to the following description, and can be modified as appropriate without departing from the gist of the present invention. In addition, in this specification, a tilde "~" indicating a numerical range means that the numerical values before and after it are included as the lower and upper limits, unless otherwise specified.

<Mixed Toner>
The mixed toner according to one embodiment is a mixed toner used in a concealing layer formed as a base layer for an image layer on a substrate having an uneven surface (hereinafter simply referred to as an uneven substrate), and contains two types of toner for the concealing layer having different viscoelasticity.

The substrate having an uneven surface is a substrate having a large uneven shape on the surface, and examples of such substrates include cloth products. Cloth products refer to shirts such as T-shirts and polo shirts, clothing such as jackets, sweatshirts, and hoodies, and textile products made of fibers such as textiles. Textiles refer to woven fabrics, dyed fabrics, knitted fabrics, cloth, and the like. The mixed toner according to one embodiment can be suitably used for shirts, and can be suitably used for T-shirts in particular.

The inventors focused on using two types of toners for the concealing layer with different viscoelasticity as the mixed toner used in the concealing layer. Of the two types of toners for the concealing layer with different viscoelasticity, the toner for the concealing layer with a low storage modulus can increase the adhesive strength with the uneven substrate and the image layer, so that the image layer can be maintained in a state in which it is stably adhered to the uneven substrate via the concealing layer. As a result, the inventors found that the image layer can exhibit color development while being adhered to the uneven substrate via the concealing layer, while improving its ability to follow the shrinkage, etc. of the uneven substrate, and improving its friction fastness.

The two types of toner for the concealing layer are composed of a first toner for the concealing layer and a second toner for the concealing layer.

It is preferable that the two types of toner for the concealing layer have different storage moduli G' in the temperature range of 150°C to 190°C. The storage moduli G' are determined by dynamic elasticity measurement.

When measuring the two types of toner for the concealing layer contained in the mixed toner, the mixed toner is placed in an elbow jet classifier (EJ-L-3, manufactured by Nittetsu Mining Co., Ltd.) to separate the toner for the first concealing layer and the toner for the second concealing layer contained in the mixed toner. After that, the storage modulus G' of the separated toner for the first concealing layer and the toner for the second concealing layer are each measured.

The dynamic viscoelasticity of the toner for the concealing layer at 150° C. to 190° C. can be measured using a known measuring device. For example, 0.8 g of the toner for the concealing layer is molded using a die with a diameter of 20 mm at a pressure of 30 MPa, and the toner is measured under the following measurement conditions using a parallel cone with a diameter of 20 mm in an ADVANCED RHEOMETRIC EXPANSION SYSTEM manufactured by TA Corporation. The storage modulus G' of the toner for the concealing layer at 150° C. to 190° C. is read from the obtained measurement data.
[Measurement condition]
Frequency: 1.0Hz
Heating rate: 2.0°C/min. Distortion: 0.1% (automatic distortion control: minimum allowable stress 1.0 g/cm, maximum allowable stress 500 g/cm, maximum additional distortion 200%, distortion adjustment 200%)

The storage modulus G' of the toner for the first concealing layer at 150° C. to 190° C. is preferably 1.0×10 ¹ Pa to 1.0×10 ⁴ Pa , more preferably 5.0×10 ¹ Pa to 5.0×10 ³ Pa , and even more preferably 1.0×10 ² Pa to 1.0×10 ³ Pa .

The storage modulus G' of the other toner for the second concealing layer at 150°C to 190°C is preferably 1.0 x ¹⁰⁵ Pa to 1.0 x ¹⁰⁷ Pa , more preferably 9.8 x ¹⁰⁵ Pa to 5.0 x ¹⁰⁶ Pa , and even more preferably 1.1 x ¹⁰⁶ Pa to 1.3 x ¹⁰⁷ Pa .

It is preferable that the volume average particle size of the toner for the first concealing layer is different from the volume average particle size of the toner for the second concealing layer. It is preferable that the volume average particle size of the toner for the first concealing layer is larger than the volume average particle size of the toner for the second concealing layer. The ratio of the volume average particle size of the toner for the first concealing layer to the toner for the second concealing layer is preferably more than 1.5 times and less than 15 times, more preferably more than 1.5 times and less than 10 times, and even more preferably more than 2 times and less than 10 times.

The volume average particle size of the toner for the first concealing layer and the toner for the second concealing layer can be measured using a known method, for example, using a particle size analyzer (Coulter Counter Multisizer III). The measurement sample is prepared by adding the toner for the first concealing layer or the toner for the second concealing layer as a measurement toner to an electrolyte solution to which a surfactant has been added, and dispersing the toner for one minute using an ultrasonic disperser. 50,000 particles of this are measured. The volume average particle size of the toner for the first concealing layer and the toner for the second concealing layer may also be measured using another particle size analyzer (Nanotrac Wave-UT151, manufactured by Microtrac Bell Co., Ltd.).

The volume average particle diameter of the toner for the second concealing layer is preferably greater than 3 μm. If the volume average particle diameter of the toner for the second concealing layer is less than 3 μm, problems tend to occur in handling in the electrophotographic process. For example, the charge is too high, which tends to cause development transfer failure, cleaning failure, or component contamination due to filming.

The volume average particle diameter of the toner for the first concealing layer is preferably 150 μm or less, and more preferably 100 μm or less. If the volume average particle diameter of the toner for the first concealing layer is 150 μm or less, problems are likely to occur in handling in the electrophotographic process, for example, causing poor development transfer due to reduced charge, and causing background scumming or toner scattering.

The mixed toner is preferably used as a transparent toner that does not contain a colorant or a white toner that contains a colorant. The mixed toner is used as a concealing layer formed on the surface of the uneven substrate, and an image layer is formed on the concealing layer. If the mixed toner is a transparent toner or a white toner, the decrease in color development of the image layer is suppressed.

The components of the toner for the first concealing layer and the toner for the second concealing layer contained in the mixed toner are described below. The toner for the first concealing layer and the toner for the second concealing layer may contain similar components.

The toner for the first concealing layer and the toner for the second concealing layer contain a binder resin. In addition to the binder resin, the toner for the first concealing layer and the toner for the second concealing layer may contain other components such as a colorant and a release agent as necessary.

The binder resins contained in the toner for the first concealing layer and the toner for the second concealing layer may be the same or different.

[Binder resin]
The binder resin can include a polymer resin.

The polymer resin is not particularly limited as long as it is a polymer obtained by a condensation polymerization reaction or an addition polymerization reaction, and examples of the polymer resin that can be used include polymer resins obtained by a condensation polymerization reaction and polymer resins obtained by an addition polymerization reaction.

Polymer resins obtained by condensation polymerization reactions include polyester resins, polyamide resins, and polyester-polyamide resins. It is preferable that the polymer resins contained as binder resins in the toner for the first concealing layer and the toner for the second concealing layer both contain polyester resins.

Polyester resin is a polymer obtained by condensation polymerization of a polyhydric hydroxy compound and a polybasic acid.

Examples of polyhydric hydroxy compounds include glycols such as ethylene glycol, diethylene glycol, triethylene glycol, and propylene glycol, alicyclic compounds containing two hydroxyl groups such as 1,4-bis(hydroxymethyl)cyclohexane, and dihydric phenol compounds such as bisphenol A. Polyhydric hydroxy compounds also include those containing three or more hydroxyl groups.

Examples of polybasic acids include dibasic carboxylic acids such as maleic acid, fumaric acid, phthalic acid, isophthalic acid, terephthalic acid, succinic acid, and malonic acid, as well as tribasic or higher polybasic carboxylic acid monomers such as 1,2,4-benzenetricarboxylic acid, 1,2,5-benzenetricarboxylic acid, 1,2,4-cyclohexanetricarboxylic acid, 1,2,4-naphthalenetricarboxylic acid, 1,2,5-hexanetricarboxylic acid, 1,3-dicarboxyl-2-methylenecarboxypropane, and 1,2,7,8-octanetetracarboxylic acid.

In addition to the above-mentioned monomer raw materials, examples of raw material monomers for polyamide resins and polyester-polyamide resins include monomers that form amide components, such as polyamines such as ethylenediamine, pentamethylenediamine, hexamethylenediamine, phenylenediamine, and triethylenetetramine, and aminocarboxylic acids such as 6-aminocaproic acid and ε-caprolactam. From the viewpoint of thermal storage stability, the glass transition temperature Tg of polyamide and polyester-polyamide resins is preferably 55°C or higher, and more preferably 57°C or higher.

Polymer resins obtained by addition polymerization reactions are not particularly limited, and include vinyl resins produced by radical polymerization. Raw material monomers for addition polymerization resins include styrene, o-methylstyrene, m-methylstyrene, p-methylstyrene, α-methylstyrene, p-ethylstyrene, vinylnaphthalene; ethylenically unsaturated monoolefins such as ethylene, propylene, butylene, and isobutylene; vinyl esters such as vinyl chloride, vinyl bromide, vinyl acetate, and vinyl formate; acrylic acid, methyl acrylate, ethyl acrylate, n-propyl acrylate, isopropyl acrylate, tert-butyl acrylate, amyl acrylate, methacrylic acid, methyl methacrylate, ethyl methacrylate, Examples of suitable ethylenic monocarboxylic acids and esters thereof include n-propyl methacrylate, isopropyl methacrylate, tert-butyl methacrylate, amyl methacrylate, stearyl methacrylate, methoxyethyl methacrylate, glycidyl methacrylate, phenyl methacrylate, dimethylaminoethyl methacrylate, and diethylaminoethyl methacrylate; ethylenic monocarboxylic acid substitutes such as acrylonitrile, methacrylonitrile, and acrylamide; ethylenic dicarboxylic acids and substitutes thereof such as dimethyl maleate; and vinyl ketones such as vinyl methyl ketone.

Specific examples of polymer resins obtained by addition polymerization reactions include styrene acrylic, styrene butadiene, etc.

When using a polymer resin obtained by addition polymerization reaction as the polymer resin, a crosslinking agent can be added as necessary. As a crosslinking agent for the raw material monomer of the addition polymerization resin, a common crosslinking agent such as divinylbenzene, divinylnaphthalene, polyethylene glycol dimethacrylate, diethylene glycol dimethacrylate, triethylene glycol diacrylate, dipropylene glycol dimethacrylate, polypropylene glycol dimethacrylate, diallyl phthalate, etc. can be used.

The content of the crosslinking agent is preferably 0.05 to 15 parts by mass, and more preferably 0.1 to 10 parts by mass, per 100 parts by mass of the raw material monomer of the addition polymerization resin. If the content of the crosslinking agent is 0.05 to 15 parts by mass, the effect of the crosslinking agent can be fully exerted, the binder resin can be melted by heat, and poor fixing can be suppressed when fixing the binder resin using heat.

In addition, a polymerization initiator can be used when polymerizing the raw material monomers of the addition polymerization resin. Examples of the polymerization initiator include 2,2'-azobis(2,4-dimethylvaleronitrile), 2,2'-azobisisobutyronitrile, other azo or diazo polymerization initiators, or peroxide polymerization initiators such as benzoyl peroxide, methyl ethyl ketone peroxide, and 2,4-dichlorobenzoyl peroxide. Two or more types of polymerization initiators can be used for the purpose of adjusting the molecular weight and molecular weight distribution of the polymer.

The content of the polymerization initiator is preferably 0.05 to 15 parts by mass, and more preferably 0.5 to 10 parts by mass, per 100 parts by mass of the raw material monomer of the addition polymerization resin.

When using a polymer resin obtained by a condensation polymerization reaction or an addition polymerization reaction, the resulting polymer resin may be a non-linear polymer resin having a non-linear structure or a linear polymer resin having a linear structure, depending on the types of reaction raw materials in the condensation polymerization reaction or addition polymerization reaction. In this embodiment, both non-linear polymer resins and linear polymer resins are used. Note that non-linear polymer resins refer to polymer resins that have a substantial cross-linked structure. Linear polymer resins refer to polymer resins that do not substantially have a cross-linked structure.

In addition, in this embodiment, it is preferable to use a hybrid resin in which a polymer resin obtained by a condensation polymerization reaction and a polymer resin obtained by an addition polymerization reaction are chemically bonded as the polymer resin. The hybrid resin can be obtained by polymerization using a compound that can react with both the polymer resin obtained by the condensation polymerization reaction and the monomer contained in the polymer resin obtained by the addition polymerization reaction. A bireactive monomer can be used as a compound that can react with both the polymer resin obtained by the condensation polymerization reaction and the monomer contained in the polymer resin obtained by the addition polymerization reaction. Examples of the bireactive monomer include compounds such as fumaric acid, acrylic acid, methacrylic acid, maleic acid, and dimethyl fumarate.

The content of the bireactive monomer is preferably 1 to 25 parts by mass, and more preferably 2 to 10 parts by mass, per 100 parts by mass of the monomer contained in the polymer resin obtained by the addition polymerization reaction. If the content of the bireactive monomer is 1 to 25 parts by mass, it is possible to prevent deterioration of the dispersibility of the colorant and charge control agent, and to suppress deterioration of image quality such as fogging. It is also possible to suppress gelation of the polymer resin.

For the hybrid resin, it is not necessary to simultaneously proceed and complete both the condensation polymerization and addition polymerization reactions, and the reaction temperature and time for each reaction can be selected to complete the reaction independently. For example, the following method can be used to complete the reaction independently. First, a mixture of raw material monomers and a polymerization initiator contained in a polymer resin obtained by an addition polymerization reaction (e.g., vinyl resin, etc.) is dropped into a mixture of raw material monomers contained in a polymer resin obtained by a condensation polymerization reaction (e.g., polyester resin, etc.) in a reaction vessel, and mixed, and the polymerization reaction of the raw material monomers contained in the polymer resin obtained by the addition polymerization reaction is completed by a radical reaction, and a polymer resin obtained by an addition polymerization reaction is produced. Next, the reaction temperature is increased to condense the raw material monomers contained in the polymer resin obtained by the condensation polymerization reaction, thereby producing a polymer resin obtained by a condensation polymerization reaction. With this method, two independent reactions are allowed to proceed in parallel in a reaction vessel, and two types of polymer resins can be effectively dispersed.

The toner for the first concealing layer and the toner for the second concealing layer may contain other binder resins than the above polymer resins as the binder resin, to the extent that the performance of the toner for the first concealing layer and the toner for the second concealing layer is not impaired. Examples of other binder resins include known binder resins such as polyurethane resins, silicone resins, ketone resins, styrene-acrylic resins, styrene resins, acrylic resins, epoxy resins, diene resins, phenolic resins, terpene resins, coumarin resins, amide-imide resins, butyral resins, ethylene-vinyl acetate resins, petroleum-based resins, and hydrogenated petroleum-based resins. These resins may be used alone or in combination of two or more.

[Other ingredients]
The toner for the first concealing layer and the toner for the second concealing layer may contain other components, such as a colorant, a release agent, a release agent dispersant, a charge control agent, an external additive, a flowability improver, a cleaning property improver, and a magnetic material.

(Coloring Agent)
The colorant is not particularly limited and can be appropriately selected depending on the purpose, and examples thereof include black pigments, yellow pigments, magenta pigments, cyan pigments, etc. Among these, it is preferable to contain any one of yellow pigments, magenta pigments, and cyan pigments.

Black pigments are used, for example, in black toner. Examples of black pigments include carbon black, copper oxide, manganese dioxide, aniline black, activated carbon, non-magnetic ferrite, magnetite, nigrosine dye, and iron black.

Yellow pigments are used, for example, in yellow toners. Examples of yellow pigments include C.I. Pigment Yellow 74, 93, 97, 109, 128, 151, 154, 155, 166, 168, 180, and 185, Naphthol Yellow S, Hansa Yellow (10G, 5G, and G), Cadmium Yellow, Yellow Iron Oxide, Yellow Yellow, Yellow Lead, Titanium Yellow, and Polyazo Yellow.

Magenta pigments are used, for example, in magenta toners. Examples of magenta pigments include quinacridone pigments and monoazo pigments such as C.I. Pigment Red 48:2, 57:1, 58:2, 5, 31, 146, 147, 150, 176, 184, and 269. Quinacridone pigments may also be used in combination with monoazo pigments.

Cyan pigments are used, for example, in cyan toners. Examples of cyan pigments include Cu-phthalocyanine pigments, Zn-phthalocyanine pigments, and Al-phthalocyanine pigments.

The content of the colorant in the first concealment toner or the second concealment toner is not particularly limited and can be selected appropriately depending on the purpose, but is preferably 1 part by mass to 15 parts by mass, and more preferably 3 parts by mass to 10 parts by mass, per 100 parts by mass of the first concealment toner or the second concealment toner.

(White pigment)
The white pigment is preferably a titanium dioxide pigment, which is preferably surface-treated with at least a polyol, and more preferably coated with at least aluminum and trimethylolpropane and/or trimethylolethane.

White pigments include commercially available products such as Typeque PF-739, Typeque CR-50-2, and Typeque CR-60-2 (all manufactured by Ishihara Sangyo Kaisha). Among these, Typeque PF-739 has a reduced moisture absorption amount due to zirconia treatment, and is suitable for use in the first concealment toner and the second concealment toner.

The volume average particle diameter of the white pigment is preferably 200 nm to 300 nm, and more preferably 220 nm to 270 nm. By making the volume average particle diameter of the white pigment 200 nm to 300 nm, the effect of the white pigment on the physical properties of the binder resin can be suppressed. In addition, when the mixed toner is used as a concealing layer, a decrease in concealing power can be suppressed.

The content of the white pigment is preferably 37% to 45% by mass relative to the first concealing toner and the second concealing toner. If the content of the white pigment is 37% to 45% by mass, the concealing layer containing the first concealing toner and the second concealing toner can have sufficient concealing power and can suppress the influence on the thermal properties of the first concealing toner and the second concealing toner. In addition, the influence on the thermal properties of the first concealing toner and the second concealing toner is suppressed, and it is possible to suppress the image gloss from becoming uncontrollable due to the viscoelasticity becoming too large.

(Release agent)
The release agent is not particularly limited and can be appropriately selected.

The release agents that can be used include liquid paraffin, microcrystalline wax, natural paraffin, synthetic paraffin, polyolefin wax, and partial oxides thereof; aliphatic hydrocarbons such as fluorides and chlorides; animal oils such as beef tallow and fish oil; vegetable oils such as coconut oil, soybean oil, rapeseed oil, rice bran wax, and carnauba wax; higher aliphatic alcohols and higher fatty acids such as montan wax; metal soaps such as fatty acid amides, fatty acid bisamides, zinc stearate, calcium stearate, magnesium stearate, aluminum stearate, zinc oleate, zinc palmitate, magnesium palmitate, zinc myristate, zinc laurate, and zinc behenate; fatty acid esters, polyvinylidene fluoride, and the like. These may be used alone or in combination of two or more.

Among these, it is preferable to contain at least an ester wax, such as a fatty acid ester. If a toner contains a maleic acid modified polyolefin having a polypropylene block in the main chain, and the content is high, there is a problem that the toner cannot be separated from the fixing roller (or fixing belt) during fixing, resulting in waste paper jams. By adding an ester wax as a release agent, such problems can be suppressed.

The content of the release agent in the first concealment toner and the second concealment toner is preferably 0.1% to 8.0% by mass. If the content is 0.1% to 8.0% by mass, the first concealment toner and the second concealment toner can be separated from the fixing roller (or fixing belt) during fixing, and clogging of waste paper can be suppressed. In addition, when fixing to a plastic film, the first concealment toner and the second concealment toner can be sufficiently fixed to the plastic film.

(Release agent dispersant)
The release agent dispersant has a function of helping to disperse the release agent. The release agent dispersant is not particularly limited, and known ones can be used. Examples of the release agent dispersant include polymers and oligomers in which a unit highly compatible with the release agent and a unit highly compatible with the resin exist as a block body; polymers or oligomers in which one of a unit highly compatible with the release agent and a unit highly compatible with the resin is grafted to the other; copolymers of unsaturated hydrocarbons such as ethylene, propylene, butene, styrene, α-styrene, etc., and α,β-unsaturated carboxylic acids such as acrylic acid, methacrylic acid, maleic acid, maleic anhydride, itaconic acid, itaconic anhydride, etc., or esters or anhydrides thereof; block and graft bodies of vinyl resins and polyesters, etc.

The above-mentioned units that are highly compatible with release agents include long-chain alkyl groups with 12 or more carbon atoms, polyethylene, polypropylene, polybutene, polybutadiene, and copolymers of these.

Examples of units that are highly compatible with resins include polyester and vinyl resins.

(Charge control agent)
The charge control agent is not particularly limited and can be appropriately selected according to the purpose, and examples thereof include modified products of nigrosine and fatty acid metal salts, onium salts such as phosphonium salts and their lake pigments, triphenylmethane dyes and their lake pigments, metal salts of higher fatty acids, diorganotin oxides such as dibutyltin oxide, dioctyltin oxide, and dicyclohexyltin oxide, diorganotin borates such as dibutyltin borate, dioctyltin borate, and dicyclohexyltin borate, organometallic complexes, chelate compounds, monoazo metal complexes, acetylacetone metal complexes, aromatic hydroxycarboxylic acids, and aromatic dicarboxylic acid-based metal complexes, quaternary ammonium salts, aromatic monocarboxylic acids and aromatic polycarboxylic acids, their metal salts, anhydrides, and esters, and phenol derivatives such as bisphenol. These may be used alone or in combination of two or more.

The content of the charge control agent is not particularly limited and can be appropriately selected depending on the purpose, but is preferably 0.1 to 10 parts by weight, more preferably 0.2 to 5 parts by weight, relative to 100 parts by weight of the first concealment toner or the second concealment toner. If the content exceeds 10 parts by weight, the chargeability of the first concealment toner or the second concealment toner becomes too high, which reduces the effect of the main charge control agent and increases the electrostatic attraction force with the developing roller, which may lead to a decrease in the fluidity of the developer and a decrease in image density. In addition, since the charge control agent may cause coloring, it is preferable to use a transparent color as much as possible, except for black toner.

(External additives)
As the external additive, inorganic fine particles and the like can be used.

The inorganic fine particles have the function of imparting fluidity, developability, chargeability, etc. to the first concealment toner or the second concealment toner. The inorganic fine particles are not particularly limited and can be appropriately selected from known fine particles depending on the purpose. Examples of inorganic fine particles that can be used include alumina, silica, titanium oxide, barium titanate, magnesium titanate, calcium titanate, strontium titanate, zinc oxide, tin oxide, silica sand, clay, mica, wollastonite, diatomaceous earth, chromium oxide, cerium oxide, pengala, antimony trioxide, magnesium oxide, zirconium oxide, barium sulfate, barium carbonate, calcium carbonate, silicon carbide, and silicon nitride. These may be used alone or in combination of two or more.

The inorganic fine particles may be surface-treated to increase the hydrophobicity of the surface and suppress deterioration of flow characteristics and charging characteristics even under high humidity. Preferred surface treatment agents include, for example, fluorine-containing silane coupling agents, silylating agents, silane coupling agents having a fluorinated alkyl group, organic titanate coupling agents, aluminum coupling agents, silicone oils, modified silicone oils, etc. Among these, it is preferable to use a silane coupling agent or a fluorine silane coupling agent.

The content of inorganic fine particles is preferably 0.4 parts by mass to 4.0 parts by mass, and more preferably 1.0 parts by mass to 2.2 parts by mass, per 100 parts by mass of the first concealment toner or the second concealment toner. If the content of inorganic fine particles is 0.4 parts by mass to 4.0 parts by mass, the fluidity and cohesiveness of the first concealment toner or the second concealment toner can be sufficiently improved, the texture of the halftone image can be reduced, and the problem of white spots in the image due to the aggregation of the first concealment toner and the second concealment toner can be reduced. In addition, the minimum fixing temperature of the first concealment toner and the second concealment toner can be increased, and the decrease in low-temperature fixing property can be suppressed.

The average particle size of the primary particles of the inorganic fine particles is not particularly limited and can be selected appropriately depending on the purpose, but is preferably 100 nm or less, and more preferably 3 nm to 70 nm. Within this range, the inorganic fine particles are not embedded in the first concealment toner and the second concealment toner, and can effectively exert their function while reducing uneven damage to the photoreceptor surface.

(Flow improver)
The flowability improver is not particularly limited as long as it is capable of performing a surface treatment to increase hydrophobicity and prevent deterioration of flowability and charging properties even under high humidity, and can be appropriately selected according to the purpose, and examples thereof include silane coupling agents, silylating agents, silane coupling agents having a fluorinated alkyl group, organic titanate coupling agents, aluminum coupling agents, silicone oils, modified silicone oils, etc. It is particularly preferable that the silica and titanium oxide are surface-treated with such a flowability improver and used as hydrophobic silica and hydrophobic titanium oxide.

(Cleaning improver)
The cleaning property improver is not particularly limited as long as it is added to the toner in order to remove the developer remaining on the photoconductor or primary transfer medium after transfer, and may be appropriately selected depending on the purpose, and examples thereof include fatty acid metal salts such as zinc stearate, calcium stearate, and stearic acid, polymer fine particles produced by soap-free emulsion polymerization such as polymethyl methacrylate fine particles and polystyrene fine particles. The polymer fine particles preferably have a relatively narrow particle size distribution, and are preferably ones having a volume average particle size of 0.01 μm to 1 μm.

(Magnetic Materials)
The magnetic material is not particularly limited and may be appropriately selected depending on the purpose, and examples thereof include iron powder, magnetite, ferrite, etc. Among these, a white material is preferred in terms of color tone.

The first concealing toner and the second concealing toner can be manufactured using a known manufacturing method.

The method for producing the first concealment toner includes a step of obtaining a binder resin mixture (mixing step), a step of obtaining a kneaded mixture (melting and kneading step), a step of obtaining a solid product of the kneaded mixture (solidification step), a step of obtaining a pulverized product of the solid product (fine-pulverizing step), and a step of classifying and recovering the pulverized product (classification step).

In the mixing process, the binder resin, colorant, release agent, and optionally the charge control agent are mixed in a mixer such as a Henschel mixer or super mixer to obtain a mixture.

In the melt-kneading process, the mixture is melt-kneaded using a hot melt kneader such as a heated roll, kneader, or extruder to obtain a kneaded product.

In the solidification process, the kneaded material is cooled and solidified to obtain a solid material.

In the fine pulverization step, the solid material is pulverized to obtain a pulverized material. The solid material can be pulverized using a known pulverization method. Examples of pulverization methods that can be used include a jet mill method in which the first concealment toner is contained in a high-speed airflow and the solid material is pulverized by the energy generated when the first concealment toner is collided with a collision plate, an interparticle collision method in which the first concealment toner is collided with itself in an airflow, and a mechanical pulverization method in which the first concealment toner is supplied between a narrow gap and a rotor rotating at high speed to pulverize the first concealment toner.

In the classification process, the pulverized material is classified to recover pulverized material having a predetermined volume average particle size. This allows the first concealment toner to be obtained.

The first concealment toner can also be manufactured using a dissolution suspension method. When manufacturing the first concealment toner using the dissolution suspension method, the oil phase in which toner materials such as a binder resin, a colorant, a release agent, and optionally a charge control agent are dissolved or dispersed in an organic solvent phase is dispersed in an aqueous medium phase, and the binder resin is reacted, followed by removing the solvent, filtering, washing, and drying to manufacture the base particles of the first concealment toner. The base particles obtained using the dissolution suspension method are granulated to obtain the first concealment toner.

The second concealing toner can be manufactured in the same manner as the first concealing toner, so details will be omitted.

As described above, the mixed toner according to one embodiment is a mixed toner used for a concealing layer formed on a substrate having irregularities, and includes a first concealing layer toner and a second concealing layer toner as two types of concealing layer toners having different viscoelasticity. The storage modulus G' of one of the first concealing layer toners at 150°C to 190°C is set to 1.0×10 ¹ Pa to 1.0×10 ⁴ Pa , and the storage modulus G' of the other of the second concealing layer toners at 150°C to 190°C is set to 1.0×10 ⁵ Pa to 1.0×10 ⁷ Pa . In the mixed toner according to one embodiment, the concealing layer toner having low viscoelasticity among the first concealing layer toner and the second concealing layer toner can increase the adhesive strength between the concealing layer and the image layer, so that the state in which the image layer is adhered to the concealing layer via the concealing layer can be stably maintained. In addition, the concealing layer formed using the mixed toner according to an embodiment is formed by including two types of toners for the concealing layer having different viscoelasticity, and thus has moderate flexibility, and even if the uneven substrate has an uneven surface and is easily deformed, such as a cloth product, the concealing layer can be easily deformed to follow the uneven substrate. Furthermore, since the concealing layer formed using the mixed toner according to an embodiment can easily follow the movement of the uneven substrate, the concealing layer can be prevented from peeling or cracking from the uneven substrate, and therefore the concealing layer is less susceptible to the influence of the unevenness and color of the surface of the uneven substrate, and the desired color reproducibility and color development of the image layer can be prevented from being impaired.

Therefore, by using the mixed toner according to one embodiment, the image layer can exhibit good color development when adhered to the uneven substrate via the concealing layer, and the ability to follow the shrinkage of the uneven substrate, etc. can be improved, and the friction fastness can be increased, so that an image with excellent color development and friction fastness can be formed.

In one embodiment, the mixed toner can have a ratio of the volume average particle diameter of the toner for the first concealing layer to the volume average particle diameter of the toner for the second concealing layer greater than 1.5 and less than 10. When a concealing layer is formed using the mixed toner, the toner for the second concealing layer contained in the concealing layer can easily penetrate by following the surface shapes of the uneven substrate and the image layer, thereby improving the adhesion between the concealing layer and the uneven substrate and the image layer. Therefore, the mixed toner can easily form an image with excellent abrasion resistance.

The mixed toner according to one embodiment can be a transparent toner or a white toner. This allows the concealing layer to be transparent or white, suppressing the loss of the color reproducibility and color development desired by the image layer, and improving the color reproducibility and color development of the image layer.

The mixed toner according to one embodiment can be used with a fabric product as the substrate. Even if the substrate is a fabric product, the concealing layer formed using the mixed toner can increase adhesion to the surface of the fabric product, so that the image layer can be maintained in a state of being stably adhered to the fabric product via the concealing layer. Therefore, by using the mixed toner according to one embodiment, an image with excellent color development and abrasion fastness can be formed on the surface of the fabric product.

<Developer>
The developer according to an embodiment includes the toner according to an embodiment, and may include other components, such as a carrier, that are appropriately selected as necessary. This allows high-quality images to be stably formed.

The developer may be either a one-component developer or a two-component developer, but when used in high-speed printers that correspond to the recent improvements in information processing speed, a two-component developer is preferable in terms of extending the developer's lifespan.

When the toner according to one embodiment is used as a single-component developer, there is little variation in the particle size of the toner even when the toner is balanced, and there is little toner filming on the developing roller or toner melting onto components such as blades that thin the toner layer, and good, stable developability and images can be obtained even with long-term stirring in the developing device.

When the developer according to one embodiment is used as a two-component developer, it can be mixed with a carrier and used as a developer. When the toner according to one embodiment is used as a two-component developer, there is little fluctuation in the particle size of the toner even when the toner is balanced over a long period of time, and good and stable developability and images can be obtained even with long-term stirring in the developing device.

The amount of carrier in the two-component developer can be selected appropriately depending on the purpose, but it is preferably 90 parts by weight to 98 parts by weight, and more preferably 93 parts by weight to 97 parts by weight, per 100 parts by weight of the two-component developer.

The developer according to one embodiment can be suitably used for image formation using various known electrophotographic methods, such as a magnetic one-component development method, a non-magnetic one-component development method, and a two-component development method.

[Career]
Magnetic fine particles can be used as the carrier. As the magnetic fine particles, spinel ferrites such as magnetite and gamma iron oxide, spinel ferrites containing one or more metals other than iron (Mn, Ni, Zn, Mg, Cu, etc.), magnetoplumbite ferrites such as barium ferrite, and iron or alloy particles having an oxide layer on the surface can be used. In consideration of chemical stability, it is preferable to use magnetite, spinel ferrites containing gamma iron oxide, and magnetoplumbite ferrites such as barium ferrite. Specifically, MFL-35S, MFL-35HS (manufactured by Powder Tech Co., Ltd.), DFC-400M, DFC-410M, SM-350NV (manufactured by Dowa Iron Powder Co., Ltd.), etc. are mentioned as suitable examples.

In particular, when high magnetization is required as the carrier, it is preferable to use ferromagnetic fine particles such as iron as the carrier.

The shape of the carrier may be granular, spherical, or needle-like.

By appropriately selecting the type and content of the carrier, a resin carrier with the desired magnetization can be used. In this case, the magnetic properties of the resin carrier preferably have a magnetization strength of 30 emu/g to 150 emu/g at 1,000 oersteds.

Such a resin carrier can be produced by spraying a molten mixture of the carrier and insulating binder resin with a spray dryer, or by reacting and curing a monomer or prepolymer in an aqueous medium in the presence of the carrier, to produce a resin carrier in which the carrier is dispersed in a condensation binder.

The chargeability can be controlled by adhering positively or negatively charged particles or conductive particles to the surface of the carrier, or by coating it with resin.

Surface coating materials (resins) that can be used include silicone resins, acrylic resins, epoxy resins, fluorine-based resins, etc. Furthermore, coatings containing positively or negatively charged particles or conductive particles can be used, with silicone resins and acrylic resins being preferred.

The weight ratio of the carrier in the developer contained in the developing device is preferably 85% to less than 98% by weight. If the weight ratio is 85 wt% or more and less than 98% by weight, scattering of toner from the developing device is easily suppressed, and the occurrence of defective images can be reduced. In addition, excessive increase in the charge amount of the electrophotographic developing toner and insufficient supply of the electrophotographic developing toner can be suppressed, so that the occurrence of defective images due to a decrease in image density can be reduced.

<Toner storage unit>
The toner storage unit according to the embodiment can store the mixed toner according to the embodiment. The toner storage unit according to the embodiment refers to a unit having a function of storing the mixed toner, and stores the mixed toner. Here, examples of the toner storage unit include a toner storage container, a developing device, and a process cartridge.

A toner storage container is a container that stores mixed toner.

A developer is a device that contains a means for storing and developing mixed toner.

A process cartridge is a device that integrates at least an electrostatic latent image carrier (also called an image carrier) and a developing means, contains a mixed toner, and is detachable from an image forming device. The process cartridge may further include at least one selected from a charging means, an exposure means, a cleaning means, etc.

The toner storage unit according to one embodiment stores the mixed toner according to one embodiment. By mounting the toner storage unit according to one embodiment on an image forming apparatus and forming an image, the mixed toner according to one embodiment is used to form an image, so that it is possible to form an image that takes advantage of the characteristics of the toner, which forms an image with excellent color development and abrasion resistance.

<Image forming apparatus>
The image forming apparatus according to one embodiment includes an electrostatic latent image carrier, an electrostatic latent image forming unit that forms an electrostatic latent image on the electrostatic latent image carrier, a developing unit that develops the electrostatic latent image using a chromatic toner to form a chromatic toner image, a first transfer unit that transfers the chromatic toner image to a release paper, a first fixing unit that fixes the chromatic transfer image transferred to the release paper to form an image layer, a second transfer unit that transfers a toner image to the surface of the image layer opposite the release paper side using a mixed toner, a second fixing unit that fixes the concealing transfer image transferred to the image layer to form a concealing layer, a third fixing unit that fixes the image surface of the concealing layer opposite the image layer side to a substrate having an uneven surface, and a peeling unit that peels the release paper from the concealing layer, and may further have other configurations as necessary.

In the second transfer section, the mixed toner according to one embodiment is used. Preferably, a toner image may be formed by using a developer that contains the mixed toner according to one embodiment and, if necessary, other components such as a carrier.

The second transfer section and the second fixing section can be performed multiple times, and the concealing layer can have multiple layers.

(Electrostatic Latent Image Carrier)
The material, shape, structure, size, etc. of the electrostatic latent image carrier (sometimes called "electrophotographic photoreceptor" or "photoreceptor") are not particularly limited and can be appropriately selected from known materials. Examples of materials for the electrostatic latent image carrier include inorganic photoreceptors such as amorphous silicon and selenium, and organic photoreceptors (OPC) such as polysilane and phthalopolymethine. Among these, organic photoreceptors (OPC) are preferred because they can provide higher resolution images. A preferred shape of the electrostatic latent image carrier is a drum shape.

(Electrostatic latent image forming section)
The electrostatic latent image forming unit is not particularly limited as long as it is a means for forming an electrostatic latent image on an electrostatic latent image carrier, and can be appropriately selected according to the purpose. The electrostatic latent image forming unit includes, for example, a charging member (charger) for uniformly charging the surface of the electrostatic latent image carrier, and an exposure member (exposure unit) for imagewise exposing the surface of the electrostatic latent image carrier.

The charger is not particularly limited and can be appropriately selected depending on the purpose, but examples include contact chargers equipped with conductive or semiconductive rolls, brushes, films, rubber blades, etc., and non-contact chargers that use corona discharge such as corotrons and scorotrons.

The charger is preferably one that is arranged in contact or non-contact with the electrostatic latent image carrier and charges the surface of the electrostatic latent image carrier by applying superimposed DC and AC voltages. It is also preferable that the charger is a charging roller that is arranged in close proximity to the electrostatic latent image carrier but not in contact with it via a gap tape, and that the surface of the electrostatic latent image carrier is charged by applying superimposed DC and AC voltages to the charging roller.

The exposure device is not particularly limited as long as it can expose the surface of the electrostatic latent image carrier charged by the charger in the form of an image to be formed, and can be appropriately selected depending on the purpose. Examples of the exposure device include various exposure devices such as a copying optical system, a rod lens array system, a laser optical system, and a liquid crystal shutter optical system. A light back system in which exposure is performed in the form of an image from the back side of the electrostatic latent image carrier may also be used.

(Developing section)
The developing unit is not particularly limited as long as it can develop the electrostatic latent image formed on the electrostatic latent image carrier to form a visible chromatic toner image, and can be appropriately selected according to the purpose. For example, the first developing unit can be suitably used one that contains chromatic toner and has a developing unit that can apply the chromatic toner to the electrostatic latent image in a contact or non-contact manner, and a developing unit equipped with a toner container is preferable.

The developing device may be a single-color developing device or a multi-color developing device, and a suitable example would be one that has an agitator that charges the toner by friction and agitation, and a rotatable magnetic roller.

(First transfer section)
The first transfer section preferably has a primary transfer section that transfers a chromatic toner image onto an intermediate transfer body to form a composite transfer image, and a secondary transfer section that transfers the composite transfer image onto a release paper. The intermediate transfer body is not particularly limited and can be appropriately selected from known transfer bodies depending on the purpose, and a transfer belt or the like is preferably used.

The first transfer section (primary transfer section and secondary transfer section) preferably has at least a transfer device that peels and charges the chromatic toner image formed on the electrostatic latent image carrier (photoconductor) onto the release paper. The first transfer section may be one, or two or more.

Examples of transfer devices include corona transfer devices using corona discharge, transfer belts, transfer rollers, pressure transfer rollers, adhesive transfer devices, etc. The recording medium is not particularly limited and can be appropriately selected from known recording media (recording paper).

(First fixing section)
The first fixing section is not particularly limited and can be appropriately selected depending on the purpose, but a known heating and pressurizing section is suitable. Examples of the heating and pressurizing section include a combination of a heating roller and a pressure roller, and a combination of a heating roller, a pressure roller, and an endless belt.

The first fixing section is preferably a heating and pressurizing section that has a heating element having a heat generating element, a film in contact with the heating element, and a pressure member that is in pressure contact with the heating element via the film, and that can heat and fix the image by passing a release paper on which an unfixed image has been formed between the film and the pressure member. Heating in the heating and pressurizing section is usually preferably 80°C to 200°C. In this embodiment, a known optical fixing device, for example, may be used together with or instead of the first fixing section depending on the purpose.

(Second transfer section)
The second transfer unit can have a similar configuration to the first transfer unit, and so details thereof will be omitted.

(Second fixing section)
The second fixing section is not particularly limited and can be appropriately selected depending on the purpose, but a known heating and pressing section can be suitably used. Examples of the heating and pressing section include a heat press machine (e.g., Model HTP234PS1, manufactured by Piotek Corporation).

(others)
The image forming apparatus according to the first embodiment may further include, for example, a static eliminator, a recycle unit, a controller, and the like.

(Static charge removal section)
The charge removing section is not particularly limited as long as it can apply a charge removing bias to the electrostatic latent image bearing member, and can be appropriately selected from known charge removers. Suitable examples include charge removing lamps.

(Cleaning Department)
The cleaning unit may be any type capable of removing the toner remaining on the electrostatic latent image carrier, and may be appropriately selected from among known cleaners. Examples of the cleaning unit include a magnetic brush cleaner, an electrostatic brush cleaner, a magnetic roller cleaner, a blade cleaner, a brush cleaner, and a web cleaner.

The image forming apparatus according to the first embodiment has a cleaning section, which improves the cleaning performance. In other words, by controlling the adhesion between toner particles, the fluidity of the toner is controlled, and the cleaning performance can be improved. In addition, by controlling the characteristics of the toner after deterioration, it is possible to maintain excellent cleaning quality even under harsh conditions such as a long life or high temperature and humidity. Furthermore, since the external additives can be sufficiently liberated from the toner on the photoreceptor, a deposition layer (dam layer) of the external additives in the cleaning blade nip can be formed, thereby achieving high cleaning performance.

(Recycling Department)
The recycling section is not particularly limited, and examples thereof include known conveying means.

((Control Unit))
The control unit can control the movement of each of the above-mentioned parts. The control unit is not particularly limited as long as it can control the movement of each of the above-mentioned parts, and can be appropriately selected depending on the purpose. For example, the control unit can be a control device such as a sequencer or a computer.

The image forming apparatus according to one embodiment can form images using the toner according to one embodiment, and therefore can provide high-quality images with excellent color development and abrasion resistance.

<Image forming method>
The image forming method according to one embodiment includes an electrostatic latent image forming step of forming an electrostatic latent image on an electrostatic latent image carrier, a developing step of developing the electrostatic latent image using a chromatic toner to form a chromatic toner image, a first transfer step of transferring the chromatic toner image to a release paper, a first fixing step of fixing the chromatic transfer image transferred to the release paper to form an image layer, a second transfer step of transferring a toner image to the surface of the image layer opposite the release paper side using a mixed toner, a second fixing step of fixing the toner image transferred to the image layer to form a concealing layer, a third fixing step of fixing the image surface of the concealing layer opposite the image layer side to a substrate having an uneven surface, and a peeling step of peeling the release paper from the concealing layer, and may further include other steps as necessary.

The image forming method according to one embodiment can be suitably performed by the image forming apparatus according to the above-mentioned embodiment. That is, the electrostatic latent image forming process can be suitably performed by the electrostatic latent image forming unit, the developing process can be suitably performed by the developing unit, the first transfer process can be suitably performed by the first transfer unit, the first fixing process can be suitably performed by the first fixing unit, the second transfer process can be suitably performed by the second transfer unit, the second fixing process can be suitably performed by the second fixing unit, the third fixing process can be suitably performed by the third fixing unit, the peeling process can be suitably performed by the peeling and developing unit, and the other processes can be suitably performed by the other units.

In the second transfer step, the mixed toner according to one embodiment is used. Preferably, a toner image may be formed by using a developer that contains the mixed toner according to one embodiment and, if necessary, other components such as a carrier.

It is preferable that the second transfer step and the second fixing step are performed multiple times to form multiple layers of the concealing layer.

Each process is explained below.

In the electrostatic latent image forming process, an electrostatic latent image is formed on the electrostatic latent image carrier. The electrostatic latent image forming process includes a charging process for charging the surface of the electrostatic latent image carrier, and an exposure process for exposing the charged surface of the electrostatic latent image carrier to light to form an electrostatic latent image. Charging can be performed, for example, by applying a voltage to the surface of the electrostatic latent image carrier using a charger. Exposure can be performed, for example, by exposing the surface of the electrostatic latent image carrier to light in an imagewise manner using the exposure device. The electrostatic latent image can be formed, for example, by uniformly charging the surface of the electrostatic latent image carrier and then exposing it to light in an imagewise manner, and can be performed by the electrostatic latent image forming unit.

In the developing process, the electrostatic latent image is developed sequentially with multiple chromatic toners to form a visible image. The visible image can be formed, for example, by developing the electrostatic latent image with chromatic toners to form a chromatic toner image, which can be done by a developing device.

In the developing device, for example, chromatic toner and carrier are mixed and stirred, and the chromatic toner becomes charged by friction during this process and is held in a standing state on the surface of the rotating magnet roller, forming a magnetic brush. Since the magnet roller is placed near the electrostatic latent image carrier (photoconductor), some of the chromatic toner that constitutes the magnetic brush formed on the surface of the magnet roller moves to the surface of the electrostatic latent image carrier (photoconductor) by electrical attraction. As a result, the electrostatic latent image is developed with chromatic toner, and a chromatic toner image, which is a visible image made of chromatic toner, is formed on the surface of the electrostatic latent image carrier (photoconductor).

In the first transfer step, the chromatic toner image is transferred to a release paper. FIG. 1 shows the state in which the chromatic toner image has been transferred to a release paper. As shown in FIG. 1, in the first transfer step, the chromatic toner image 1A is transferred to the release paper P1.

The first transfer step preferably uses an intermediate transfer body, and after the chromatic toner image is primarily transferred onto the intermediate transfer body, the chromatic toner image is secondarily transferred onto a release paper. The first transfer step more preferably includes a first transfer step using two or more color toners, preferably full-color toners, in which the chromatic toner image is transferred onto the intermediate transfer body to form a composite transfer image, and a second transfer step in which the composite transfer image is transferred onto a recording medium. The transfer can be performed, for example, by charging the electrostatic latent image carrier (photoconductor) with the chromatic toner image using a transfer charger, and can be performed by the transfer section.

In the first fixing process, the chromatic transfer image, in which the chromatic toner image is transferred to the release paper, is fixed using a fixing device to form an image layer. Figure 2 is a diagram showing the state in which the image layer is formed on the release paper. As shown in Figure 2, in the first fixing process, the chromatic transfer image is fixed to form an image layer 1B on the release paper P1.

The first fixing step may be performed for each color developer each time it is transferred to a release paper, or it may be performed simultaneously for each color developer in a stacked state.

The first transfer step and the first fixing step may be performed multiple times to form an image layer in multiple layers.

In the second transfer step, a toner image is transferred using the mixed toner to the surface of the image layer opposite the release paper. FIG. 3 is a diagram showing the state in which the toner image has been transferred to a chromatic toner image. As shown in FIG. 3, in the second transfer step, toner image 2A-1 is transferred onto image layer 1B. The second transfer step can be performed using the same transfer method as the first transfer step, so details of the transfer method are omitted.

In the second fixing step, the concealing transfer image, which is the toner image transferred onto the image layer, is fixed using a fixing device to form a concealing layer. FIG. 4 is a diagram showing the state in which the concealing layer has been formed on the image layer. As shown in FIG. 4, in the second transfer step, the toner image 2A-1 (see FIG. 3) is fixed onto the image layer 1B, so that the concealing layer 2B-1 is formed on the image layer 1B. The second fixing step can be performed using the same fixing method as the first fixing step, so details of the fixing method are omitted.

The second transfer step and the second fixing step are preferably performed multiple times to form a concealing layer in multiple layers. This allows a concealing layer of any thickness to be easily formed. In this embodiment, the second transfer step and the second fixing step are performed twice to form two concealing layers. FIG. 5 is a diagram showing the state in which two concealing layers have been formed. As shown in FIG. 5, the toner image 2A-2 is transferred onto the image layer 2B-1 and then fixed, so that the concealing layer 2B-2 can be formed on the concealing layer 2B-1. This allows the concealing layer 2B to be composed of two layers, the concealing layer 2B-1 and the concealing layer 2B-2.

In the third fixing step, the image surface of the concealing layer 2B opposite to the image layer 1B side is fixed to a substrate (concave-convex substrate) 3 having a concave-convex surface. FIG. 6 is a diagram showing the state in which the concealing layer 2B is laminated on the concave-convex substrate 3. As shown in FIG. 6, the concealing layer 2B is placed on the concave-convex substrate 3 with the image surface of the concealing layer 2B in contact with the concave-convex substrate 3.

Then, the release paper P1 and the substrate 3 having the unevenness are heat-pressed using a heat press machine. FIG. 7 is a diagram showing an example of the state in which the release paper P1 and the substrate 3 having the unevenness are heat-pressed using a heat press machine. As shown in FIG. 7, a laminate in which the uneven substrate 3, the concealing layer 2B, the image layer 1B, and the release paper P1 are laminated in this order from the uneven substrate 3 side is placed between the upper press 5A and the lower press 5B of the heat press 5, and the release paper P1 and the uneven substrate 3 are heat-pressed.

When performing the heat press, the heating temperature, press pressure, press time, etc. of the upper press 5A and the lower press 5B can be selected as appropriate.

Figure 8 shows the state after the release paper P1 and the substrate 3 having the unevenness are heat-pressed. As shown in Figure 8, by heat-pressing the release paper P1 and the substrate 3 having the unevenness, the concealing layer 2B can be laminated on the substrate 3 having the unevenness in a state where the concealing layer 2B and the substrate 3 are in close contact with each other.

In the peeling process, the release paper is peeled off from the concealing layer. Figure 9 is a diagram showing the state in which the release paper is peeled off from the concealing layer. As shown in Figure 9, by peeling the release paper P1 from the concealing layer 2B, a thermal transfer image can be obtained in which the concealing layer 2B and the image layer 1B are laminated in this order on the uneven substrate 3.

The image forming method according to the first embodiment may further include other steps appropriately selected as necessary, such as a static elimination step, a cleaning step, a recycling step, etc.

The static elimination process is a process in which a static elimination bias is applied to the electrostatic latent image carrier to eliminate static electricity, and can be suitably performed by the static elimination unit.

The cleaning process is a process for removing the toner remaining on the electrostatic latent image carrier, and can be suitably performed by the cleaning unit.

The recycling process is a process in which the toner removed in the cleaning process is recycled to the development section, and can be suitably carried out by the recycling section.

The image forming method according to one embodiment can form an image using the mixed toner according to one embodiment, and therefore can provide high-quality images with excellent color development and abrasion resistance.

The following examples and comparative examples are used to further explain the embodiments, but the embodiments are not limited to these examples and comparative examples.

<Production of Nonlinear Polyester Resin (A)>
6.2 mol of fumaric acid, 6.5 mol of trimellitic anhydride, 4 mol of bisphenol A (2,2) propylene oxide, and 5 mol of bisphenol A (2,2) ethylene oxide were placed in a flask equipped with a stainless steel stirring rod, a downflow condenser, a nitrogen gas inlet tube, and a thermometer, and a condensation polymerization reaction was carried out with stirring at a temperature of 250° C. under a nitrogen atmosphere to obtain a nonlinear polyester resin A. The softening point Tm of the obtained nonlinear polyester resin A was 162.1° C.

<Production of Linear Polyester Resin (B)>
7.5 mol of terephthalic acid, 1.5 mol of isophthalic acid, 4.2 mol of bisphenol A (2,2) propylene oxide, and 4.7 mol of bisphenol A (2,2) ethylene oxide were placed in a flask equipped with a stainless steel stirring rod, a downflow condenser, a nitrogen gas inlet tube, and a thermometer, and a condensation polymerization reaction was carried out with stirring at a temperature of 250° C. under a nitrogen atmosphere to obtain a linear polyester resin B. The softening point Tm of the obtained linear polyester resin B was 100.5° C.

<Production of Hybrid Resin (C)>
16 mol of styrene as an addition polymerization reaction monomer, 4 mol of butyl methacrylate, and 0.35 mol of t-butyl hydroperoxide as a polymerization initiator were placed in a dropping funnel, 8.0 mol of fumaric acid as an addition polymerization and condensation polymerization reactive monomer, 4.5 mol of trimellitic anhydride as a condensation polymerization reaction monomer, 7.0 mol of bisphenol A (2,2) propylene oxide, 2.6 mol of bisphenol A (2,2) ethylene oxide, and 58 mol of dibutyltin oxide as an esterification catalyst were placed in a flask equipped with a stainless steel stirring rod, a downflow condenser, a nitrogen gas inlet tube, and a thermometer. Then, while stirring these mixtures at 138 ° C. under a nitrogen atmosphere, a mixture of addition polymerization raw materials mixed in advance was dropped from the dropping funnel over a period of 4 hours. After completion, the mixture was aged for 6.5 hours while maintaining the temperature at 138 ° C., and then heated to 250 ° C. and reacted to obtain a hybrid resin C. The softening point Tm of the obtained hybrid resin C was 139.4 ° C.

<Production of Monoester Wax>
A 1-liter four-neck flask equipped with a thermometer, a nitrogen inlet tube, a stirrer, and a cooling tube was charged with 50 parts by mass of cerotic acid and 50 parts by mass of palmitic acid as fatty acid components, and 100 parts by mass of ceryl alcohol as an alcohol component, so that the total amount was 500 g. The reaction was carried out at normal pressure for 15 hours or more under a nitrogen stream while distilling off the reactants at 220°C, to obtain a monoester wax having a melting point of 71°C.

<Masterbatch manufacturing example>
[Manufacturing of black master batch]
100 parts by mass of carbon black (Regal 400R, manufactured by Cabot Corporation), 150 parts by mass of polyester resin B, and 30 parts by mass of water were added and mixed in a Henschel mixer (manufactured by Nippon Coke and Engineering Co., Ltd.) to obtain a mixture. The obtained mixture was kneaded using two rolls at 160°C for 50 minutes, rolled and cooled, and pulverized with a pulperizer to obtain a black master batch.

[Production of masterbatches of other colors]
A magenta master batch, a cyan master batch and a yellow master batch were prepared in the same manner except that C. I. Pigment Red 269, C. I. Pigment Blue 15:3 and C. I. Pigment Yellow 155 were used instead of carbon black.

<Preparation of Toner 1 for Image Layer>
The following components were mixed in the amounts shown below to obtain a mixture.
Linear polyester resin (B): 40.0 parts by weight Non-linear polyester resin (C): 60.0 parts by weight Charge control agent (salicylic acid derivative zirconium salt): 0.8 parts by weight Monoester wax: 4.0 parts by weight Colorant (cyan master batch (cyan MB)): 12.0 parts by weight

The salicylic acid derivative zirconium salt used was the compound of the following structural formula (1).

L1 in the above structural formula (1) represents the following structure:

A mixture having the above composition was premixed using a Henschel mixer (FM20B, manufactured by Mitsui Miike Chemical Engineering Co., Ltd.), and then melted and kneaded at a temperature of 120°C in a twin-screw kneader (PCM-30, manufactured by Ikegai Corporation). The resulting kneaded material was rolled to a thickness of 2 mm using rollers, cooled to room temperature using a belt cooler, and coarsely pulverized to 200 μm to 500 μm using a feather mill. Next, it was finely pulverized using a jet mill pulverizer (manufactured by Nippon Pneumatic Mfg. Co., Ltd.), and then classified using an air classifier (MDS-I, manufactured by Nippon Pneumatic Mfg. Co., Ltd.) while appropriately adjusting the louver opening so that the mass average particle size was 6.3 μm, and toner base particles (cyan) were obtained. 100 parts by weight of the obtained toner base particles were mixed with 1.0 part by weight of HDK-2000 (manufactured by Clariant Co., Ltd.) and 1.0 part by weight of H05TD (manufactured by Clariant Co., Ltd.) as external additives using a Henschel mixer to obtain toner 1 for the image layer.

(Average particle size)
The volume average particle diameter of the toner 1 for forming the image layer was measured using a Coulter Counter Multisizer III, and the volume average particle diameter of the toner 1 for forming the image layer was found to be 6.3 μm.

(Measurement of softening point Tm)
The softening temperature was measured using a high-temperature flow tester (manufactured by Shimadzu Corporation) in accordance with the method described in JIS K72101. A ^{1 cm3} sample was heated at a temperature increase rate of 6°C/min, while a load of 30 kg/ ^cm2 was applied by the plunger to push out a nozzle with a diameter of 1 mm and a length of 1 mm. A plunger drop vs. temperature curve was then drawn, and the height of the S-shaped curve was taken as h. The temperature corresponding to h/2 (the temperature at which half of the resin flowed out) was taken as the softening point Tm of the toner 1 for the image layer.

<Preparation of Toner A for Concealing Layer>
The following components were mixed in the amounts shown below to obtain a mixture.
Linear polyester resin (B): 60.0 parts by weight Non-linear polyester resin (C): 40.0 parts by weight Charge control agent (zirconium salt of salicylic acid derivative): 0.8 parts by weight Monoester wax: 4.0 parts by weight PF-739 (manufactured by Ishihara Sangyo Kaisha): 65.0 parts by weight

The mixture of the above composition was classified in the same manner as in the preparation of toner 1 for the image layer, while appropriately adjusting the louver opening so that the mass average particle size was 5.7 μm, to obtain toner base particles. 100 parts by mass of the obtained toner base particles were mixed with 1.0 part by mass of HDK-2000 (manufactured by Clariant Co., Ltd.) and 1.0 part by mass of H05TD (manufactured by Clariant Co., Ltd.) as external additives by stirring in a Henschel mixer to obtain toner A for the concealment layer.

<Preparation of Toners B to N for Concealing Layer>
Except for changing the components and the amounts of each component shown in Table 1 as shown in Table 1, the procedure was the same as for the concealing layer toner A, and concealing layer toners B to N were prepared.

The composition, average particle size, softening point Tm, and storage modulus G' of image-forming toner 1 and concealing layer toners A to N are shown in Table 1.

<Production Example of Two-Component Developer>
[Preparation of Carrier A]
The following components were mixed in the amounts shown below to obtain a mixture.
Silicone resin (organo straight silicone): 100 parts by weight Toluene: 100 parts by weight γ-(2-aminoethyl)aminopropyltrimethoxysilane: 5 parts by weight Carbon black: 10 parts by weight

The above mixture was dispersed in a homomixer for 20 minutes to prepare a coating layer forming liquid. This coating layer forming liquid was applied and dried using a fluidized bed coating device, with the temperature in the fluidized tank controlled to 70°C, so that the average film thickness on the core surface would be 0.20 μm, using Mn ferrite particles with a mass average particle size of 40 μm as the core material. The obtained carrier was baked in an electric furnace at 180°C for 2 hours to obtain carrier A.

[Preparation of Carrier B]
Carrier B having a weight average particle size of 80 μm was obtained in the same manner as in carrier A, except that Mn ferrite particles having a mass average particle size of 40 μm were used.

<Preparation of Two-Component Developer>
[Preparation of Two-Component Developer A]
The thus prepared toner 1 for the image layer (color toner) or toner A for the concealment layer (transparent toner) and carrier A were uniformly mixed and charged for 5 minutes at 48 rpm using a Turbula mixer (manufactured by Willy & Bachofen (WAB)) to prepare a developer for the image layer or a developer for the concealment layer as two-component developer A. The mixing ratio of the toner and carrier A was adjusted to 7% by mass, which was the toner concentration of the initial developer of the evaluation machine.

[Preparation of Two-Component Developer B]
The same procedure was carried out for the preparation of two-component developer A, except that carrier B was used instead of carrier A, and as two-component developer B, a developer for the image layer or a developer for the concealing layer was prepared.

Example 1
[Preparation of thermal transfer print sheet]
As the developer for the image layer, a two-component developer was prepared by mixing the toner 1 for the image layer and the carrier A. As the developer for the concealing layer, the toner A for the concealing layer, which is the toner for the first concealing layer, the toner B for the concealing layer, which is the toner for the second concealing layer, and the carrier B were mixed to prepare a two-component developer in which the ratio of the toner A for the concealing layer to the toner B for the concealing layer was 30%:70%. The prepared developer for the image layer and the developer for the concealing layer were set at the fifth station of RICOH Pro C7200S (manufactured by Ricoh Co., Ltd.), and the development and transfer conditions were adjusted by a process controller.

First, as shown in Fig. 10, an image layer was formed in the image layer forming region on the release paper by developing, transferring and fixing the developer for the image layer so as to form an image pattern in which the developer for the image layer had an adhesion amount of 1.0 mg/ ^cm2 and 0.5 mg/ ^cm2 . The image layer was formed so as to be inside the region in which the concealing layer was formed (the region in which the concealing layer was formed) in a plan view.

Next, as shown in Fig. 11, the concealing layer was formed by developing, transferring and fixing the concealing layer developer in an image pattern having an adhesion amount of 1.3 mg/ ^cm2 on the concealing layer forming area on the release paper on which the image layer was formed. This operation was repeated three times to prepare a concealing layer so that the adhesion amount of the concealing layer developer was 3.9 ± 0.2 mg/ ^cm2 . In this way, a thermal transfer print sheet was produced.

Then, with the concealing layer of the thermal transfer print sheet facing downwards and the release paper on top, the thermal transfer print sheet was placed above the black T-shirt substrate, and the laminate of the thermal transfer print sheet and the black T-shirt substrate was placed in a heat press. After applying a load and heat to the thermal transfer print sheet and the black T-shirt substrate to fix them, the black T-shirt was removed and allowed to cool until it reached 40°C or lower. The release paper of the thermal transfer print sheet was then peeled off to obtain an image-forming substrate (sample) with an image formed on the black T-shirt.

Example 2
In Example 1, the toner B for the concealing layer used as the toner for the second concealing layer contained in the developer for the concealing layer was changed to toner C for the concealing layer, and carrier B was changed to carrier A. The same procedure as in Example 1 was repeated to obtain an image forming substrate.

<Examples 3 to 6>
An image forming substrate was obtained in the same manner as in Example 1, except that the toner B for the concealing layer used as the second toner for the concealing layer contained in the developer for the concealing layer was changed to any one of the toners D to H for the concealing layer.

<Examples 7 and 8>
An image forming substrate was obtained in the same manner as in Example 1, except that the ratio of the toner A for the concealing layer and the toner B for the concealing layer contained in the developer for the concealing layer was changed. In Example 7, the ratio of the toner A for the concealing layer and the toner B for the concealing layer was 50%:50%, and in Example 8, the ratio of the toner A for the concealing layer and the toner B for the concealing layer was 70%:30%.

<Examples 9 and 10>
The procedure of Example 1 was repeated except that the toner A for the concealing layer used as the first toner for the concealing layer and the toner B for the concealing layer used as the second toner for the concealing layer, both contained in the developer for the concealing layer, were changed to the toner J for the concealing layer as the first toner for the concealing layer and the toner K for the concealing layer as the second toner for the concealing layer, to obtain an image forming substrate.

<Comparative Examples 1 and 2>
The same procedure as in Example 1 was repeated, except that the toner B for the concealing layer used as the second toner for the concealing layer contained in the developer for the concealing layer was changed to toner F for the concealing layer or toner I for the concealing layer, to obtain an image forming substrate.

<Comparative Example 3>
In Example 1, the blending amount of the concealing layer toner B used as the second concealing layer toner contained in the concealing layer developer was set to zero, and the developer was changed to only the concealing layer toner A, which is the first concealing layer toner. The carrier B contained in the concealing layer developer was changed to carrier A. The rest was performed in the same manner as in Example 1 to obtain an image forming substrate.

<Comparative Example 4>
In Example 1, the same procedure as in Example 1 was repeated, except that the amount of toner A for the concealing layer used as the toner for the first concealing layer contained in the developer for the concealing layer was set to zero, and only toner B for the concealing layer, which is the toner for the second concealing layer, was used, to obtain an image forming substrate.

<Measurement of storage modulus G′ of the toner for the first concealing layer and the toner for the second concealing layer contained in the developer for the concealing layer>
The developer for the concealing layer was placed in an elbow jet classifier (EJ-L-3, manufactured by Nittetsu Mining Co., Ltd.) to separate the toner for the first concealing layer and the toner for the second concealing layer contained in the developer for the concealing layer. Thereafter, the storage modulus G' of the separated toner for the first concealing layer and toner for the second concealing layer was measured.

0.8 g of the toner for the first concealing layer or the toner for the second concealing layer was molded at a pressure of 30 MPa using a φ20 mm die. Then, using a φ20 mm parallel cone in an ADVANCED RHEOMETRIC EXPANSION SYSTEM manufactured by TA, the storage modulus G' of the molded body at 150°C and 190°C was measured at a frequency of 1.0 Hz, a heating rate of 2.0°C/min, and a strain of 0.1% (automatic strain control: minimum allowable stress 1.0 g/cm, maximum allowable stress 500 g/cm, maximum added strain 200%, strain adjustment 200%). The measurement results of the storage modulus G' of the toner for the first concealing layer and the toner for the second concealing layer contained in the developer for the concealing layer in each example and comparative example are shown in Table 1.

<Evaluation of Image Forming Substrate>
The properties of the prepared image-forming substrates were measured and evaluated as follows. The results of the evaluation are shown in Table 2.

[Color development]
The lightness (L ^* value) of the image forming substrate was measured with a spectrophotometer (Rite 939, manufactured by X-Rite Corporation), and the color development was evaluated based on the following evaluation criteria.
(Evaluation criteria)
◎: Lightness is 70 or more. ◯: Lightness is 62 or more and less than 70. △: Lightness is 56 or more and less than 62. ×: Lightness is 55 or less.

[Friction fastness]
The friction fastness was evaluated using a friction tester type II (Gakushin type friction tester) specified in the friction fastness test (JIS L 0849). An image-forming substrate was fixed to the surface of the friction tester type II with a length of 100 mm, and a cotton cloth was attached to the friction tester type II and brought into contact with the surface of the image-forming substrate so that a load of about 200 g was applied. Then, the cotton cloth was slid back and forth 100 times over a length of 100 mm with a load of about 200 g applied to the image-forming substrate. Then, the cotton cloth was removed from the tester, and a gray scale for staining as shown in FIG. 12 was used to determine the value of the friction fastness by judging "staining", and the friction fastness was evaluated based on the following evaluation criteria.
(Evaluation criteria)
⊚: Contamination was grade 4-5 or higher.
○: Contamination was grade 4.
Δ: Contamination was grade 3.
×: Contamination was less than grade 3.

From Table 2, it was confirmed that the image layer of the thermal transfer substrate having a shielding layer formed using the two types of toner for the concealing layer in Examples 1 to 13 met the conditions for use in terms of both color development and friction fastness. In contrast, it was confirmed that the image layer of the thermal transfer substrate having a shielding layer formed using the two types of toner for the concealing layer in Comparative Examples 1 to 4 did not meet the conditions for use in terms of either color development or friction fastness, and thus had practical problems.

Therefore, unlike the mixed toners containing two types of toners for the concealing layer in Examples 1 to 13 or one type of toner for the concealing layer in Comparative Examples 1 to 5, the mixed toners containing two types of toners for the concealing layer with different viscoelasticity and the storage modulus of the two types of toners for the concealing layer are each within a specified range, it can be said that they can be used as mixed toners that can form images with excellent color development and friction fastness.

Although the embodiments have been described above, they are presented as examples, and the present invention is not limited to the above embodiments. The above embodiments can be implemented in various other forms, and various combinations, omissions, substitutions, modifications, etc. can be made without departing from the gist of the invention. These embodiments and their variations are included in the scope and gist of the invention, and are included in the scope of the invention and its equivalents described in the claims.

10 Image forming device

JP 2016-118677 A

Claims (12)

A toner mixture used in a concealing layer formed on a substrate having an uneven surface, comprising:
The toner for the concealing layer includes two types of toners having different viscoelasticity,
the storage modulus G' of one of the toners for the first concealing layer at 150° C. to 190° C. is 1.0×10 ¹ Pa to 1.0×10 ⁴ Pa ;
The storage modulus G' of the other toner for the second concealing layer at 150° C. to 190° C. is 1.0×10 ⁵ Pa to 1.0×10 ⁷ Pa . The mixed toner according to claim 1, wherein the ratio of the volume average particle diameter of the toner for the first concealing layer to the volume average particle diameter of the toner for the second concealing layer is greater than 1.5 and less than 10. The mixed toner according to claim 1 or 2, wherein the mixed toner is a transparent toner or a white toner that does not contain a colorant. The mixed toner according to any one of claims 1 to 3, wherein the substrate is a fabric product. A developer comprising the mixed toner according to any one of claims 1 to 4 and a carrier. A toner storage unit containing the mixed toner according to any one of claims 1 to 4. An electrostatic latent image carrier;
an electrostatic latent image forming unit for forming an electrostatic latent image on the electrostatic latent image carrier;
a developing section for developing the electrostatic latent image with a chromatic toner to form a chromatic toner image;
a first transfer section for transferring the chromatic toner image onto a release paper;
a first fixing section for fixing the chromatic color transfer image transferred onto the release paper to form an image layer;
a second transfer section that transfers a toner image onto a surface of the image layer opposite to the release paper side by using a mixed toner;
a second fixing section for fixing the concealing transfer image transferred to the image layer to form a concealing layer;
a third fixing section for fixing the image surface of the front concealing layer opposite to the image layer side to a substrate having an uneven surface;
A peeling section that peels the release paper from the concealing layer;
Equipped with
5. An image forming apparatus, wherein the mixed toner is the mixed toner according to claim 1. The image forming device according to claim 7, wherein the concealing layer has multiple layers. The image forming apparatus according to claim 7 or 8, wherein the image layer is a color toner layer containing at least one type of chromatic color. the first fixing unit is a fixing device equipped with a heating roller,
10. The image forming apparatus according to claim 7, wherein the second fixing section is a heat press machine. an electrostatic latent image forming step of forming an electrostatic latent image on an electrostatic latent image carrier;
a developing step of developing the electrostatic latent image with a chromatic toner to form a chromatic toner image;
a first transfer step of transferring the chromatic toner image onto a release paper;
a first fixing step of fixing the chromatic color transfer image transferred onto the release paper to form an image layer;
a second transfer step of transferring a toner image onto the surface of the image layer opposite to the release paper side using a mixed toner;
a second fixing step of fixing the concealing transfer image transferred to the image layer to form a concealing layer;
a third fixing step of fixing the image side of the front concealing layer opposite to the image layer side to a substrate having an uneven surface;
a peeling step of peeling the release paper from the concealing layer;
Including,
An image forming method, wherein the mixed toner is the mixed toner according to any one of claims 1 to 4. The image forming method according to claim 11, in which the second transfer step and the second fixing step are performed multiple times to form multiple layers of the concealing layer.

Images