Toner for electrostatic charge image development, method for producing the same, image forming method, image forming system, and output product using the same

Abstract

To provide a toner for electrostatic charge image development that can bring about an antibacterial and antiviral effect also in a non-image area in digital printing, a method for manufacturing the same, and an image forming method using the same, an image forming system, and an output object.SOLUTION: A toner for electrostatic charge image development includes a toner base particle containing at least a binder resin, and a photosensitizer having a singlet oxygen generation ability is contained inside the toner base particle or in an external additive attached to the toner base particle.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to an electrostatic charge image developing toner, a method for manufacturing the same, an image forming method using the same, an image forming system, and an output product. More specifically, the present invention relates to an electrostatic charge image developing toner capable of exerting an antibacterial and antiviral effect on non-image areas in digital printing, a method for manufacturing the same, and the like.

Background Art

[0002] In recent years, with the spread of infectious diseases, there has been an increasing demand for printed materials having antibacterial and antiviral effects in the commercial and industrial printing fields. Under such circumstances, various antibacterial and antiviral printing methods, such as applying a varnish containing an antibacterial agent to the surface of a printed material or attaching a laminate film having an antibacterial function, have been carried out in order to impart an antibacterial function. For example, Patent Document 1 discloses an aqueous varnish containing a sensitizer phenalene compound having a singlet oxygen generation ability, and it is said that an antibacterial and antiviral effect can be exhibited even in an indoor light / low humidity environment by utilizing the antibacterial and antiviral effect of singlet oxygen.

[0003] However, in the above-mentioned means and the like, after the printing process, a step of installing a protective layer having an antibacterial and antiviral function on the printing surface is added, which makes the process complicated. Further, there are problems such as poor adhesion between the printing surface and the varnish or laminate used for forming the protective layer, and the texture of the printing substrate itself being lost.

[0004] In response to the above problems, attempts have been made to perform antibacterial and antiviral printing that does not require a complicated process by imparting an antibacterial and antiviral function to the toner instead of the varnish or laminate. However, in the toner, it has not been possible to impart an antibacterial and antiviral function to non-image areas other than the image area during printing, and there has been room for improvement.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0006] The present invention has been made in view of the above problems and situations, and the problem to be solved is to provide an electrostatic charge image developing toner capable of exerting antibacterial and antiviral effects on non-image areas in digital printing, a method for producing the same, an image forming method using the same, an image forming system, and an output product.

Means for Solving the Problems

[0007] As a result of studying the causes of the above problems in order to solve the above problems, the present inventor has found that the above problems can be solved by incorporating a photosensitizer having singlet oxygen generating ability into the toner base particles or in an external additive attached to the toner base particles, and thus the present invention has been achieved. That is, the above problems according to the present invention are solved by the following means.

[0008] 1. An electrostatic charge image developing toner containing toner base particles containing at least a binder resin, wherein a photosensitizer having singlet oxygen generating ability is Dispersed in the binder resin in a single-molecule state, inside the toner base particles contained in or the photosensitizer having the singlet oxygen generation ability is supported on the metal oxide particles in a single-molecule state, adhered to the toner base particles to do and contained in an external additive, and the electrostatic charge image developing toner is characterized by this.

[0010] 2 . In the measurement of the emission spectrum of the photosensitizer, when monochromatic light corresponding to the absorption maximum wavelength of the absorption spectrum of the solution of the photosensitizer is irradiated, phosphorescence having an emission maximum wavelength attributed to singlet oxygen is observed within the range of 1270 ± 20 nm, which is the first in the item described electrostatic charge image developing toner.

[0011] 3 . As the indicator of the singlet oxygen generating ability, it is characterized by exhibiting coloring derived from the single-molecule absorption spectrum of the photosensitizer according to claim 1 or The in item 2 toner for electrostatic charge image development according to the description.

[0012] 4 . The photosensitizer is a phthalocyanine dye or an analog thereof, and the toner for electrostatic charge image development according to any one of claims 1 to 3 the claims.

[0013] 5 . The photosensitizer has a structure represented by the following general formula (1), and the toner for electrostatic charge image development according to any one of claims 1 to 4 the claims.

[0014] [Chemical formula] (In the above general formula (1), M represents a Group 14 metal atom. Q1 and Q2 each independently represent a monovalent axial ligand. Note that the above general formula (1) may not have either Q1 or Q2. A1 to A4 each independently represent an atomic group that forms an aromatic ring which may have a substituent.)

[0016] 6 . The metal oxide particles contain a compound itself having a structure represented by the following general formula (2) or a reactant formed by reacting and bonding with an atom or functional group contained in the metal oxide particles, and are characterized by the following 1 item from any one of item 3 to item 5 The toner for electrostatic charge image development according to the description. General formula (2): PS-(OH) n (In the formula, PS represents a photosensitizer having singlet oxygen generating ability. n represents an integer.)

[0017] 7 . PS in the general formula (2) is , f A toner for electrostatic charge image development according to claim 6 , characterized in that it contains a thallocyanine dye or an analog thereof.

[0018] 8 . A method for producing a toner for electrostatic charge image development for producing the toner for electrostatic charge image development according to any one of claims 1 to 7 , characterized in that it has a step of dispersing the photosensitizer in a monomolecular state.

[0019] 9 . An image forming method using the toner for electrostatic charge image development according to any one of claims 1 to 7 , characterized in that dot formation is performed independently of the image portion. in the non-image area The image forming method characterized by the above.

[0020] 10 . The image forming method according to claim 9 , characterized in that the diameter of the dot is 60 μm or less.

[0021] 11 . An image forming system having a charging means for a photoreceptor, a latent image forming means, a developing means, a transfer means, and a cleaning means, characterized in that the toner for electrostatic charge image development according to any one of claims 1 to 7 is used.

[0022] 12 . An output formed using a toner for electrostatic charge image development, characterized in that it is formed using the toner for electrostatic charge image development according to any one of claims 1 to 7 .

Advantages of the Invention

[0023] By the above means of the present invention, it is possible to provide a toner for electrostatic charge image development capable of exerting an antibacterial and antiviral effect on non-image portions in digital printing, a method for producing the same, an image forming method, an image forming system, and an output using the same. Although the mechanism of the expression or action of the effects of the present invention has not been clearly elucidated, it is presumed as follows.

[0024] The toner for electrostatic charge image development of the present invention is a toner for electrostatic charge image development containing toner base particles containing at least a binder resin, wherein a photosensitizer having a singlet oxygen generation ability is contained inside the toner base particles or in an external additive attached to the toner base particles.

[0025] On the other hand, for the formation of the image part of a printed matter having a general antibacterial and antiviral effect, varnishes and laminates containing antibacterial and antiviral agents (Ag, Cu, Zn, etc.) are used. However, since the antibacterial and antiviral agents (Ag, Cu, Zn, etc.) are not gases, the antibacterial and antiviral effects do not diffuse to the non-image parts other than the image part during printing.

[0026] With respect to the above varnishes and the like, the toner for electrostatic charge image development of the present invention contains a photosensitizer having a singlet oxygen generation ability and generates singlet oxygen upon irradiation with indoor light. Since singlet oxygen is a gas, it diffuses not only to the image part but also to the non-image part during printing, resulting in an antibacterial and antiviral effect.

[0027] The photosensitizer having a singlet oxygen generation ability contained in the toner is not particularly limited, but it is considered preferable to exist in a single molecular state rather than an aggregated state in order to effectively perform energy transfer to oxygen. On the other hand, depending on the structure and physicochemical properties of the photosensitizer, it is also conceivable that the stability of the photosensitizer decreases in the single molecular state. Therefore, it is considered more preferable to take into account making the structure capable of stabilizing the photosensitizer. In the present invention, it is presumed that the problems could be solved by considering the above-described action mechanism, the stability of the photosensitizer, etc. Details of the action mechanism will be described later as appropriate.

[0028] It has been demonstrated by the technology developed by the Institute of the University of Regensburg in Germany and TriOptoTec GmbH, and the water-based varnish (Lock3) commercialized by Varcotec in Germany based on this technology, that singlet oxygen generated by a photosensitizer has antibacterial and antiviral effects (see, for example, https: / / www.sinsei-corp.co.jp / information / lock3.html).

Brief Description of the Drawings

[0029]

Figure 1

Figure 2

Figure 3

Modes for Carrying Out the Invention

[0030] The toner for electrostatic charge image development of the present invention is a toner for electrostatic charge image development containing toner base particles containing at least a binder resin, characterized in that a photosensitizer having singlet oxygen generation ability is contained inside the toner base particles or in an external additive attached to the toner base particles. This feature is a technical feature common to or corresponding to the following embodiments (aspects).

[0031] As an embodiment of the present invention, it is preferable from the viewpoint of energy transfer to oxygen that the photosensitizer is dispersed in a single-molecule state in the binder resin.

[0032] Further, in the measurement of the emission spectrum of the photosensitizer, when monochromatic light corresponding to the absorption maximum wavelength of the absorption spectrum of the solution of the photosensitizer is irradiated, it is preferable from the viewpoint of confirming the singlet oxygen generation ability that phosphorescence having an emission maximum wavelength attributed to singlet oxygen is observed within the range of 1270 ± 20 nm.

[0033] As the indicator of the singlet oxygen generation ability, it is preferable from the viewpoint of confirming the singlet oxygen generation ability that the coloring derived from the single molecule absorption spectrum of the photosensitizer is exhibited.

[0034] It is preferable from the viewpoints of singlet oxygen generation ability and thermal stability that the photosensitizer is a phthalocyanine dye or an analog thereof.

[0035] It is preferable from the viewpoint of preventing aggregation and making it into a single molecule state by suppressing the π-π stacking interaction of the conjugated plane of the photosensitizer molecule that the photosensitizer has a structure represented by the general formula (1).

[0036] From the viewpoint of the expression of the effects of the present invention, it is preferable that the toner base particles contain metal oxide particles carrying the photosensitizer.

[0037] From the viewpoint of the expression of the effects of the present invention, it is preferable that the metal oxide particles contain a compound itself having a structure represented by the general formula (2) or a reaction product formed by reacting with an atom or a functional group contained in the metal oxide particles to form a bond.

[0038] From the viewpoint of thermal stability, it is preferable that PS in the general formula (2) represents the phthalocyanine dye or an analog thereof.

[0039] The method for producing an electrostatic charge image developing toner of the present invention is a method for producing an electrostatic charge image developing toner for producing the above-mentioned electrostatic charge image developing toner, which is characterized by having a step of dispersing the photosensitizer in a single molecule state.

[0040] The image forming method of the present invention is an image forming method using the above-mentioned electrostatic charge image developing toner, which is characterized by forming dots independently of the image portion. Thereby, antibacterial and antiviral effects can be exhibited. Further, it is preferable that the diameter of the dot is 60 μm or less because the effect can be exhibited even when isolated dots are printed in a size that cannot be visually recognized.

[0041] The image forming system of the present invention is an image forming system having a charging means for a photoreceptor, a latent image forming means, a developing means, a transfer means, and a cleaning means, and is characterized by using the electrostatic charge image developing toner. Thereby, the antibacterial and antiviral effects can be exerted also in non-image areas.

[0042] The output of the present invention is an output formed using the electrostatic charge image developing toner, and is characterized by being formed using the electrostatic charge image developing toner. Thereby, the antibacterial and antiviral effects can be exerted.

[0043] Hereinafter, the present invention, its constituent elements, and the modes and aspects for implementing the present invention will be described in detail. In the present application, "~" is used in the sense of including the numerical values described before and after as the lower limit value and the upper limit value.

[0044] 1. Electrostatic charge image developing toner The electrostatic charge image developing toner of the present invention (hereinafter, also simply referred to as "toner") is an electrostatic charge image developing toner containing toner base particles containing at least a binder resin, and a photosensitizer having a singlet oxygen generating ability is contained inside the toner base particles or in an external additive attached to the toner base particles.

[0045] (1.1) Toner base particles The electrostatic charge image developing toner of the present invention (hereinafter, also referred to as "toner") includes toner particles including toner base particles and an external additive disposed on the surface of the toner base particles. In the present specification, "toner base particles" constitute the base of "toner particles". The "toner base particles" according to the present invention contain at least a binder resin, and may contain other constituent components such as a colorant, a release agent (wax), a charge control agent, etc. as required. "Toner base particles" are referred to as "toner particles" by adding an external additive. And the "toner" refers to an aggregate of toner particles. In the present invention, it is characterized in that a photosensitizer having singlet oxygen generation ability is contained inside the toner base particles or in an external additive attached to the toner base particles.

[0046] (1.2) Photosensitizer The "photosensitizer" according to the present invention is a photosensitizer for oxygen and has singlet oxygen generation ability, and is not limited to a specific structure, but refers to a photosensitizer having at least the following functions.

[0047] That is, when electrons in a photosensitizer molecule in the ground singlet (S0) state are excited to a higher energy state by light absorption to become an excited singlet (S1) state, the excited singlet (S1) state is unstable, so intersystem crossing occurs and it shifts to the excited triplet (T1) state. As described above, the photosensitizer molecule in the excited triplet (T1) state is at an energy level equivalent to the energy required for intersystem crossing of oxygen molecules, whereby triplet ( 3 Σ g ) state oxygen ( 3 O2), and energy transfer occurs between them, generating singlet ( 1 Δ g ) state oxygen ( 1 O2) (see Figure 1).

[0048] (Single molecule state) From the viewpoint of the efficiency of energy transfer from the photosensitizer to oxygen as described above, it is considered preferable that the photosensitizer is in a single molecule state in terms of preventing interactions between photosensitizer molecules, such as energy transfer and energy deactivation (quenching) between photosensitizer molecules. In order to apply the above photosensitizer to the electrostatic charge image developing toner of the present invention in a single molecule state, the photosensitizer needs to be dispersed (dissolved) in the toner in a single molecule state or immobilized on the particle surface in a single molecule state.

[0049] Among the above, it is preferable that the photosensitizer is dispersed (dissolved) in the toner in a single-molecule state, and being dispersed in the binder resin in a single-molecule state is preferable from the viewpoint of effectively performing energy transfer from the photosensitizer to oxygen and enhancing the singlet oxygen generation ability.

[0050] On the other hand, when the photosensitizer molecules are in an aggregated state, the unstable excited singlet state (S1) is stabilized by intermolecular interaction, thereby making intersystem crossing less likely to occur and it being difficult to shift to the excited triplet state (T1), and the energy transfer between the triplet state ( 3 Σ g ) oxygen ( 3 O2) is suppressed, and it is considered that it becomes difficult to generate singlet state ( 1 Δ g ) oxygen ( 1 O2).

[0051] Also, on the other hand, since the stability is lower in the single-molecule state than in the aggregated state, a photosensitizer having a chemically stable structure is more desirable. For example, it is preferable from the viewpoint of thermal stability that the photosensitizer is a phthalocyanine dye or its analog. The above phthalocyanine dye or its analog is widely used as a colorant in the form of a pigment (aggregate) in cyan toner. In particular, an electrostatic charge image developing toner containing the above phthalocyanine dye or its analog in a single-molecule state can be suitably used in an electrophotographic process involving heat fixing.

[0052] Whether the photosensitizer according to the present invention is in a single-molecule state can be confirmed by the presence or absence of an absorption peak of the solution and the coloring derived from the single-molecule absorption spectrum.

[0053] (Method for confirming single-molecule state) [Measurement of absorption spectrum] Whether the photosensitizer contained in the electrostatic charge image developing toner of the present invention exists in a single-molecule state can be confirmed by the presence or absence of an absorption peak of the photosensitizer in the measurement of the absorption spectrum of the solution.

[0054] For example, when using a phthalocyanine dye as a photosensitizer, if the phthalocyanine dye is in a single-molecule state, the absorption spectrum of the solution dissolved in the solvent shows a sharp absorption peak near 680 nm. Also, in the absorption spectrum of the solid, the presence or absence of the single-molecule state can be confirmed by whether a sharp absorption peak near 680 nm is shown as in the above case.

[0055] However, usually, since an electrostatic charge image developing toner contains a colorant in addition to the photosensitizer, there are cases where the absorption peak of the photosensitizer is hidden in the spectrum of the colorant and cannot be detected, or cases where the spectrum of the colorant is inadvertently mixed and the absorption peak of the photosensitizer and the spectrum of the colorant cannot be discriminated, etc. are assumed. In such a case, by irradiating a solid sample (in this case, an electrostatic charge image developing toner) with monochromatic light having the maximum wavelength of the single-molecule absorption of the photosensitizer and observing the emission spectrum of singlet oxygen, it is possible to determine whether or not the photosensitizer in the single-molecule state is significantly present.

[0056] When determining whether or not the phthalocyanine dye in the single-molecule state is significantly present in the solid sample, when the solid sample is irradiated with monochromatic light of 680 nm, if the phthalocyanine dye exists in the single-molecule state, a phosphorescence peak derived from singlet oxygen can be observed near 1270 nm with a fluorometer.

[0057] From the above, in the measurement of the emission spectrum of the photosensitizer, when the solid sample is irradiated with monochromatic light corresponding to the absorption maximum wavelength of the absorption spectrum of the solution of the photosensitizer, if phosphorescence having an emission maximum wavelength attributed to singlet oxygen is observed within the range of 1270 ± 20 nm, it means that the photosensitizer in the single-molecule state is significantly present in the solid sample.

[0058] Therefore, as described above, since the photosensitizer is in the single-molecule state, it is easy for intersystem crossing to occur, and it can be confirmed that the energy transfer from the photosensitizer to oxygen is effectively carried out, so it can be confirmed that the singlet oxygen generation ability is enhanced.

[0059] The principle described above will be explained below using a phthalocyanine dye as a photosensitizer. When the phthalocyanine dye is in a single-molecule state, the absorption spectra of both the solution and the solid show a sharp absorption peak near 680 nm (see Fig. 2(a)). However, when the phthalocyanine dye is in an aggregated state, the absorption waveform becomes broad due to the influence of intermolecular interaction, and the absorption peak shifts to the long-wavelength side or the short-wavelength side depending on the molecular orientation state (Fig. 2(b) shows a shift to the long-wavelength side), so it can be confirmed that the dye is no longer in the single-molecule state.

[0060] 〔Fading or discoloration〕 For example, a clear toner containing a phthalocyanine dye as a photosensitizer exhibits a blue color if the phthalocyanine dye exists in a single-molecule state in the toner. In this state, it can be visually confirmed that the ability to generate singlet oxygen is enhanced. However, since the blue color of the clear toner that has lost its single-molecule state due to deterioration of the phthalocyanine dye over time fades or changes color, this property can be utilized as an indicator of the effectiveness of the antibacterial action.

[0061] In the present invention, the "clear toner" refers to an aggregate of clear toner particles, and examples include toners that do not contain a colorant (such as a colored pigment, a colored dye, black carbon particles, black magnetic powder, etc.) that exhibits coloration by the action of light absorption or light scattering. Even a toner containing a trace amount of a colorant such as a colored pigment or a colored dye may be used, as long as the transparency is slightly reduced depending on the type and amount of internal additives and external additives such as resins and release agents.

[0062] (Structure of the photosensitizer) As will be described later, the photosensitizer (the compound used as such) used in the present invention can adopt various structures and is not limited to a specific structure. In the present invention, in particular, it is preferable that the photosensitizer has a structure represented by the following general formula (1) from the viewpoint of preventing aggregation and making it into a single molecular state by suppressing the π-π stacking interaction of the conjugated plane of the photosensitizer molecule.

[0063] The "π-π stacking interaction" is an action caused by the dispersion force acting between aromatic rings and six-membered carbon rings having a planar structure and rich in electrons delocalized by the π electron system, and refers to the action of arranging and stabilizing aromatic rings and six-membered carbon rings like stacking coins.

[0064]

Chemical formula

[0065] (In the above general formula (1), M represents a Group 14 metal atom. Q1 and Q2 each independently represent a monovalent axial ligand. Note that the above general formula (1) may not have either one of Q1 and Q2. A1 to A4 each independently represent an atomic group that may form an aromatic ring having a substituent.)

[0066] Generally, a photosensitizer in an aggregated state has extremely low solubility in a solvent or a resin monomer due to strong intermolecular interaction. Therefore, by adopting a molecular structure that allows the introduction of a soluble group onto the aromatic ring (A1 to A4) or the axial ligand of the metal ((Q1 and / or Q2)) as shown in the above general formula (1), the solubility of the photosensitizer can be improved.

[0067] In particular, introducing a soluble group onto the axial ligand (Q1 and / or Q2) of the central metal M is preferable because the effect of suppressing the π-π stacking interaction of the conjugated plane of the photosensitizer molecule is enhanced due to steric hindrance. Regarding the central metal M, a Group 14 metal atom that can take a plurality of axial ligands in the vertical direction of the conjugated plane is preferable, and a silicon atom is particularly preferable.

[0068] (Examples of photosensitizers) As described above, the photosensitizer having singlet oxygen generation ability has been described. Hereinafter, as examples of preferable compounds included in the photosensitizer having the structure represented by the general formula (1), examples of the photosensitizer having the structures represented by the general formula (1F) and the general formula (1G) are shown in Table I.

[0069] In addition, M, Q1, Q2, R1, R2, R3, and R4 described in Table I represent M, Q1, Q2, R1, R2, R3, and R4 in the following general formula (1F) and general formula (1G), and these are synonymous with M, Q1, Q2, R1, R2, R3, and R4 in the general formula (1). Further, the structural formulas (1) and (2) are shown below.

[0070] [Table 1]

[0071] [Chemical formula]

[0072] [Chemical formula]

[0073] [Chemical formula]

[0074] Next, examples other than the photosensitizer having the structure represented by the general formula (1) are shown. As the above example, an example of a photosensitizer having the structure represented by the following general formula (H) is shown in Table II.

[0075] In addition, M′, Q1 ′ , R1, R2, R3, and R4 represent M′, Q1 ′ , R1, R2, R3, and R4 in the following general formula (H). In addition, M′ represents a metal atom other than Group 14 or hydrogen (H2). Q1′ is synonymous with Q1 and Q2 in General Formula (1). Further, R1, R2, R3, and R4 are each synonymous with R1, R2, R3, and R4 in General Formula (1).

[0076]

Chemical Formula

[0077]

Table 2

[0078] Examples other than the photosensitizers having the structures represented by the above General Formula (1F), General Formula (1G), and General Formula (H) are shown below.

[0079]

Chemical Formula

[0080] (1.3) Externally added agent (metal oxide particles) The toner for electrostatic charge image development of the present invention contains toner particles in which externally added agents such as a fluidizing agent and a cleaning aid are attached to toner base particles in order to improve fluidity, chargeability, cleaning property, etc.

[0081] In the present invention, it is characterized in that a photosensitizer having a singlet oxygen generation ability is contained in the toner base particles or in the externally added agent attached to the toner base particles.

[0082] Examples of the metal oxide particles used as the externally added agent include inorganic oxide fine particles such as silica fine particles, alumina fine particles, and titanium oxide fine particles, inorganic stearic acid compound fine particles such as aluminum stearate fine particles and zinc stearate fine particles, and inorganic titanate compound fine particles such as strontium titanate and zinc titanate. These can be used alone or in combination of two or more.

[0083] In addition, these inorganic fine particles are preferably surface-treated with a silane coupling agent, a titanium coupling agent, a higher fatty acid, silicone oil, etc. to improve heat storage stability and environmental stability.

[0084] The total amount of the above metal oxide particles added is preferably in the range of 0.05 to 5 parts by mass, more preferably in the range of 0.1 to 3 parts by mass with respect to 100 parts by mass of the toner.

[0085] From the viewpoint of the expression of the effects of the present invention, it is more preferable that the metal oxide particles contain a compound having a structure represented by the following general formula (2) itself or a reaction product formed by reacting and bonding with atoms or functional groups contained in the metal oxide particles.

[0086] General formula (2): PS-(OH) n

[0087] (In the formula, PS represents a photosensitizer having the ability to generate singlet oxygen. n represents an integer.)

[0088] Examples of the metal oxide particles containing a compound having a structure represented by the general formula (2) include a case where a compound having a structure represented by the general formula (2) is adsorbed, that is, physically adsorbed, to the metal oxide particles by physical interaction, and a case where a compound having a structure represented by the general formula (2) condenses with, for example, OH groups on the surface of the metal oxide particles and the PS moiety of the general formula (2) is bonded to the particles via an oxygen atom, that is, chemisorbed.

[0089] From the viewpoint of thermal stability, it is preferable that PS in the general formula (2) is the phthalocyanine dye or its analog.

[0090] In addition, from the viewpoint of the expression of the effects of the present invention, it is more preferable to contain a compound having a structure represented by the following general formula (2A) in the same state as the compound having a structure represented by the general formula (2). General formula (2A): PS-[E(Z) n ​k

[0091] (In the formula, PS represents a photosensitizer having singlet oxygen generation ability. k represents an integer from 1 to 6. E represents an Si or Ti atom. Z represents an alkoxy group, an aryloxy group, a halogen atom, a hydroxy group, or a hydrogen atom. n represents the number of Z that can be substituted for E. When n is 2 or more, the plurality of Zs may be the same or different, but all do not simultaneously represent a hydrogen atom. Also, the bond between PS and E may be a covalent bond or a coordination bond.)

[0092] (1.4) Binder resin "Binder resin (also referred to as "binder resin")" means a resin that is used as a medium or matrix (parent body) for dispersing and holding internal additives (release agents, charge control agents, pigments, etc.) and external additives (silica, titanium oxide, etc.) contained in toner particles, and has a function of adhering to a recording medium (for example, paper) during the fixing process of a toner image. The binder resin constituting the toner for electrostatic charge image development of the present invention is not particularly limited, and examples thereof include vinyl polymers such as styrene resins, acrylic resins, and styrene-acrylic copolymer resins, olefin resins, polyester resins, silicone resins, amide resins, and epoxy resins. In particular, in order to improve transparency and color reproducibility of superimposed images, a styrene-acrylic copolymer resin having high transparency and a sharp melt property with low viscosity in melting characteristics is preferably mentioned. These can be used alone or in combination of two or more.

[0093] (Polymerizable monomer) The polymerizable monomer for forming the binder resin used in the resin fine particle dispersion preparation step described later is not particularly limited as long as it can form a desired binder resin.

[0094] For example, when a vinyl polymer such as a styrene resin, an acrylic resin, or a styrene-acrylic copolymer resin is desired as the binder resin, examples of the polymerizable monomer include styrene, o-methylstyrene, m-methylstyrene, p-methylstyrene, α-methylstyrene, p-phenylstyrene, p-ethylstyrene, 2,4-dimethylstyrene, p-tert-butylstyrene, p-n-hexylstyrene, p-n-octylstyrene, p-n-nonylstyrene, p-n-decylstyrene, p-n-dodecylstyrene, and other styrene or styrene derivatives; methyl methacrylate, ethyl methacrylate, n-butyl methacrylate, isopropyl methacrylate, isobutyl methacrylate, t-butyl methacrylate, n-octyl methacrylate, 2-ethylhexyl methacrylate, stearyl methacrylate, lauryl methacrylate, phenyl methacrylate, diethylaminoethyl methacrylate, dimethylaminoethyl methacrylate, and other methacrylic acid ester derivatives; methyl acrylate, ethyl acrylate, isopropyl acrylate, n-butyl acrylate, t-butyl acrylate, isobutyl acrylate, n-octyl acrylate, 2-ethylhexyl acrylate, stearyl acrylate, lauryl acrylate, phenyl acrylate, and other acrylic acid ester derivatives; olefins such as ethylene, propylene, and isobutylene; vinyl fluorides such as vinyl fluoride and vinylidene fluoride; vinyl esters such as vinyl propionate, vinyl acetate, and vinyl benzoate; vinyl ethers such as vinyl methyl ether and vinyl ethyl ether; vinyl ketones such as vinyl methyl ketone, vinyl ethyl ketone, and vinyl hexyl ketone; N-vinyl compounds such as N-vinylcarbazole, N-vinylindole, and N-vinylpyrrolidone; vinyl compounds such as vinyl naphthalene and vinyl pyridine; and vinyl monomers such as acrylic acid or methacrylic acid derivatives such as acrylonitrile, methacrylonitrile, and acrylamide. These vinyl monomers can be used alone or in combination of two or more.

[0095] Moreover, it is preferable to use a combination of polymerizable monomers having an ionic dissociable group. The polymerizable monomer having an ionic dissociable group has, for example, substituents such as a carboxyl group, a sulfonic acid group, and a phosphoric acid group as constituent groups. Specifically, acrylic acid, methacrylic acid, maleic acid, itaconic acid, cinnamic acid, fumaric acid, maleic acid monoalkyl ester, itaconic acid monoalkyl ester, styrene sulfonic acid, allyl sulfosuccinic acid, 2-acrylamido-2-methylpropanesulfonic acid, acid phosphoxyethyl methacrylate, etc. may be mentioned.

[0096] Furthermore, as the polymerizable monomer, a crosslinked binder resin can also be obtained by using polyfunctional vinyls such as divinylbenzene, ethylene glycol dimethacrylate, ethylene glycol diacrylate, diethylene glycol dimethacrylate, diethylene glycol diacrylate, triethylene glycol dimethacrylate, triethylene glycol diacrylate, neopentyl glycol dimethacrylate, neopentyl glycol diacrylate.

[0097] (Molecular weight) The molecular weight of the binder resin constituting the toner for electrostatic charge image development of the present invention preferably has a number average molecular weight (Mn) of 3000 to 6000, more preferably 3500 to 5500, and a ratio Mw / Mn of the weight average molecular weight (Mw) to the number average molecular weight (Mn) in the range of 2.0 to 6.0, preferably 2.5 to 5.5, as measured by gel permeation chromatography (GPC) of the THF-soluble component.

[0098] The molecular weight measurement by GPC was carried out as follows. That is, using the apparatus "HLC-8220" (manufactured by Tosoh Corporation) and the column "TSKguardcolumn+TSKgelSuperHZM-M3 series" (manufactured by Tosoh Corporation), while maintaining the column temperature at 40°C, tetrahydrofuran (THF) was flowed as the carrier solvent at a flow rate of 0.2 mL / min.

[0099] Thereafter, the measurement sample was dissolved in tetrahydrofuran to a concentration of 1 mg / mL under dissolution conditions of being treated with an ultrasonic disperser for 5 minutes at room temperature.

[0100] Next, it was treated with a membrane filter having a pore size of 0.2 μm to obtain a sample solution. 10 μL of this sample solution was injected into the apparatus together with the above carrier solvent, detected using a refractive index detector (RI detector), and the molecular weight distribution of the measurement sample was calculated using a calibration curve measured using monodisperse polystyrene standard particles.

[0101] As the standard polystyrene sample for calibration curve measurement, those manufactured by Pressure Chemical Co., Ltd. with molecular weights of 6×10 2 , 2.1×10 3 , 4×10 3 , 1.75×10 4 , 5.1×10 4 , 1.1×10 5 , 3.9×10 5 , 8.6×10 5 , 2×10 6 , 4.48×10 6 were used, and at least about 10 standard polystyrene samples were measured to create a calibration curve. Also, a refractive index detector was used as the detector.

[0102] (Softening point) The binder resin according to the present invention preferably has a softening point in the range of 75 to 112°C, more preferably in the range of 80 to 100°C. Since the softening point of the toner for electrostatic charge image development is within the above range, an appropriate molten state of the toner for electrostatic charge image development can be obtained in the fixing step, and high color reproducibility for secondary colors can be obtained.

[0103] Here, the "appropriate molten state for toner for electrostatic charge image development" means that when a color image is formed by superimposing toner images of other colors together with the toner image formed by the toner for electrostatic charge image development, for example, the cyan colorant contained in the toner image related to the toner for electrostatic charge image development and the magenta colorant contained in the toner image related to the magenta toner are in a state where the interface of the layers formed by their respective binder resins disappears in the color-overlapped and fixed color image area on the recording material, and both are uniformly dispersed and colored together, and the cyan colorant does not ooze out to the area outside the color image area.

[0104] For example, when a cyan toner is used as the toner for electrostatic charge image development of the present invention, it can be used together with a yellow toner, a magenta toner, a black toner, etc. to form a color image. Such yellow toner, magenta toner, and black toner are preferably designed so that their softening points, glass transition points, particle sizes, etc. are the same as those of the cyan toner.

[0105] Here, the softening point of the toner for electrostatic charge image development is measured as follows. That is, first, 1.1 g of cyan toner is placed in a petri dish and leveled in an environment of 20°C and 50% RH, and left for 12 hours or more.

[0106] Thereafter, it is pressed for 30 seconds with a force of 3820 kg / cm 2 using a molding machine "SSP-10A" (manufactured by Shimadzu Corporation) to create a cylindrical molded sample with a diameter of 1 cm.

[0107] Next, this molded sample is placed in an environment of 24°C and 50% RH and extruded from the hole of a cylindrical die (1 mm diameter × 1 mm) using a piston with a diameter of 1 cm starting from the end of preheating by a flow tester "CFT-500D" (manufactured by Shimadzu Corporation) under the conditions of a load of 196 N (20 kgf), a starting temperature of 60°C, a preheating time of 300 seconds, and a heating rate of 6°C / min. The offset method temperature T offset measured with an offset value of 5 mm set by the melting temperature measurement method of the heating method is taken as the softening point of the toner for electrostatic charge image development.

[0108] (glass transition point) The binder resin according to the present invention preferably has a glass transition point (Tg) in the range of 20 to 90°C, more preferably in the range of 35 to 65°C.

[0109] Here, the glass transition point (Tg) of the toner for electrostatic charge image development is measured using a differential scanning calorimeter "DSC-7" (manufactured by PerkinElmer) and a thermal analyzer controller "TAC7 / DX" (manufactured by PerkinElmer).

[0110] Specifically, 4.50 mg of the toner is enclosed in an aluminum pan "KITNO.0219-0041" and set in the sample holder of "DSC-7". An empty aluminum pan is used for the reference measurement, and temperature control of Heat-cool-Heat is performed under the measurement conditions of a temperature range of 0 to 200°C, a heating rate of 10°C / min, and a cooling rate of 10°C / min. Data in the 2nd. Heat is acquired, and the intersection of the extension line of the baseline before the rise of the first endothermic peak and the tangent line showing the maximum slope between the rising part of the first endothermic peak and the peak top is shown as the glass transition point (Tg). During the 1st. Heat heating, it is held at 200°C for 5 minutes.

[0111] (1.5) Release agent The release agent used in the production of the toner for electrostatic charge image development of the present invention is not particularly limited, and examples thereof include polyethylene wax, oxidized polyethylene wax, polypropylene wax, oxidized polypropylene wax, carnauba wax, sasol wax, rice wax, candelilla wax, jojoba oil wax, beeswax, and the like.

[0112] The content ratio of the release agent in the toner particles is usually in the range of 0.5 to 5 parts by mass, preferably in the range of 1 to 3 parts by mass, based on 100 parts by mass of the binder resin. If the content ratio of the release agent is less than 0.5 parts by mass with respect to 100 parts by mass of the binder resin, a sufficient offset prevention effect cannot be obtained. On the other hand, if it is greater than 5 parts by mass with respect to 100 parts by mass of the binder resin, the resulting toner will have low translucency and poor color reproducibility.

[0113] (Melting point) The melting point of the release agent is preferably in the range of 60 to 90°C. Thereby, the balance between heat-resistant storage stability and fixability, and toner manufacturability can be ensured.

[0114] (1.6) Colorant In the toner base particles according to the present invention, dyes and pigments generally known as colorants can be combined and used as the colorant.

[0115] The colorant according to the present invention may be one kind or more than one kind. In the present invention, the colorant is not limited to compounds with a specific structure as long as it does not affect the antibacterial and antiviral effects. In addition, when an aggregate of a phthalocyanine dye having an axial ligand, which is a photosensitizer preferably used in the present invention, is used as the colorant, excessive aggregation is suppressed, so that the absorption spectrum is relatively sharp and there is an advantage that a wide color gamut can be expressed, which has been confirmed by the experiments of the present inventors.

[0116] Examples of typical colorants include colorants for each of magenta, yellow, cyan, and black. Examples of the colorant for magenta include C.I. Pigment Red 2, 3, 5, 6, 7, 15, 16, 48:1, 53:1, 57:1, 60, 63, 64, 68, 81, 83, 87, 88, 89, 90, 112, 114, 122, 123, 139, 144, 149, 150, 163, 166, 170, 177, 178, 184, 202, 206, 207, 209, 222, 238, and 269.

[0117] Examples of colorants for yellow include C.I. Pigment Orange 31, 43, C.I. Pigment Yellow 12, 14, 15, 17, 74, 83, 93, 94, 138, 155, 162, 180, and 185.

[0118] Examples of colorants for cyan include C.I. Pigment Blue 2, 3, 15, 15:2, 15:3, 15:4, 16, 17, 60, 62, 66, and C.I. Pigment Green 7.

[0119] Examples of colorants for black include carbon black and magnetic particles.

[0120] Examples of carbon black include channel black, furnace black, acetylene black, thermal black, and lamp black.

[0121] Examples of magnetic materials of the magnetic particles include ferromagnetic metals such as iron, nickel, and cobalt; alloys containing these metals; compounds of ferromagnetic metals such as ferrite and magnetite; chromium dioxide; and alloys that do not contain ferromagnetic metals but exhibit ferromagnetism upon heat treatment.

[0122] Examples of alloys that exhibit ferromagnetism upon heat treatment include Heusler alloys such as manganese - copper - aluminum and manganese - copper - tin.

[0123] The content of the colorant in the toner base particles can be determined appropriately and independently. For example, from the viewpoint of ensuring color reproducibility of the image, it is preferably in the range of 1 to 30% by mass, and more preferably in the range of 2 to 20% by mass.

[0124] Also, the size of the colorant particles is preferably in the range of 10 to 1000 nm, more preferably in the range of 50 to 500 nm, and even more preferably in the range of 80 to 300 nm in terms of volume - average particle diameter.

[0125] The volume average particle diameter may be a catalog value. For example, the volume average particle diameter (volume-based median diameter) of a colorant can be measured by "UPA-150" (manufactured by Microtrac Bell Co., Ltd.).

[0126] (1.7) Surfactant In the colorant dispersion liquid preparation process and / or the binder resin fine particle polymerization process described later, in order to stably disperse fine particles in an aqueous medium, a surfactant may be added to the aqueous medium. As such a surfactant, various conventionally known anionic surfactants, cationic surfactants, nonionic surfactants, etc. can be used.

[0127] Examples of anionic surfactants include higher fatty acid salts such as sodium oleate; alkylaryl sulfonates such as sodium dodecylbenzenesulfonate; alkyl sulfate esters such as sodium lauryl sulfate; polyoxyethylene lauryl Ether sulfates such as sodium polyoxyethylene lauryl ether sulfate; polyoxyethylene alkylaryl ether sulfates such as sodium polyoxyethylene nonylphenyl ether sulfate; alkyl sulfosuccinate esters such as sodium monooctyl sulfosuccinate, sodium dioctyl sulfosuccinate, and sodium polyoxyethylene lauryl sulfosuccinate, and derivatives thereof, etc. can be mentioned.

[0128] Examples of cationic surfactants include aliphatic amine salts, aliphatic quaternary ammonium salts, benzalkonium salts, benzethonium chloride, pyridinium salts, imidazolinium salts, etc.

[0129] Furthermore, examples of nonionic surfactants include polyoxyethylene alkyl ethers such as polyoxyethylene lauryl ether and polyoxyethylene stearyl ether; polyoxyethylene alkyl phenyl ethers such as polyoxyethylene nonyl phenyl ether; sorbitan higher fatty acid esters such as sorbitan monolaurate, sorbitan monostearate, and sorbitan trioleate; polyoxyethylene sorbitan higher fatty acid esters such as polyoxyethylene sorbitan monolaurate; polyoxyethylene higher fatty acid esters such as polyoxyethylene monolaurate and polyoxyethylene monostearate; glycerin higher fatty acid esters such as monoglyceride oleate and monoglyceride stearate; polyoxyethylene-polyoxypropylene-block copolymers and the like.

[0130] (1.8) Charge control agent The charge control agent applicable to the toner base particles according to the present invention is a substance capable of imparting positive or negative charge by triboelectrification, and is not particularly limited as long as it is colorless, and various known positive charge control agents and negative charge control agents can be used.

[0131] The addition amount of the charge control agent is usually in the range of 0.1 to 10% by mass, preferably in the range of 0.5 to 5% by mass, based on 100% by mass of the finally obtained toner base particles.

[0132] The size of the charge control agent particles is preferably in the range of 10 to 1000 nm, more preferably in the range of 50 to 500 nm, and even more preferably in the range of 80 to 300 nm in terms of number average primary particle diameter.

[0133] (1.9) Polymerization initiator As the polymerization initiator used in the resin fine particle dispersion preparation step described later, any appropriate water-soluble polymerization initiator can be used. Specific examples of the polymerization initiator include, for example, persulfates (such as potassium persulfate and ammonium persulfate), azo compounds (such as 4,4′-azobis(4-cyanovaleric acid) and its salts, 2,2′-azobis(2-amidinopropane) salts, etc.), peroxide compounds, and the like.

[0134] (1.10) Chain transfer agent In the step of preparing the resin fine particle dispersion, a commonly used chain transfer agent can be used for the purpose of adjusting the molecular weight of the binder resin. The chain transfer agent is not particularly limited, and examples thereof include mercaptans such as 2-chloroethanol, octyl mercaptan, dodecyl mercaptan, t-dodecyl mercaptan, and styrene dimer.

[0135] (1.11) Flocculant Examples of the flocculant used in the salting-out, flocculation, and fusion steps include alkali metal salts and alkaline earth metal salts.

[0136] Examples of the alkali metal constituting the flocculant include lithium, potassium, sodium, and the like.

[0137] Examples of the alkaline earth metal constituting the flocculant include magnesium, calcium, strontium, barium, and the like. Among these, potassium, sodium, magnesium, calcium, and barium are preferred.

[0138] Examples of the counter ion (anion constituting the salt) of the alkali metal or alkaline earth metal include chloride ion, bromide ion, iodide ion, carbonate ion, sulfate ion, and the like.

[0139] (1.12) Developer The toner for developing an electrostatic charge image of the present invention can be used as a magnetic or non-magnetic one-component developer, or it may be used as a two-component developer by mixing with a carrier.

[0140] When the toner for electrostatic charge image development of the present invention is used as a two-component developer, as the carrier, magnetic particles made of conventionally known materials such as metals such as iron, ferrite, and magnetite, and alloys of these metals with metals such as aluminum and lead can be used, and ferrite particles are particularly preferable.

[0141] Also, as the carrier, a coated carrier in which the surface of the magnetic particles is coated with a coating agent such as a resin, a binder-type carrier in which magnetic fine powder is dispersed in a binder resin, or the like may be used.

[0142] The coating resin constituting the coated carrier is not particularly limited, and examples thereof include olefin resins, styrene resins, styrene-acrylic resins, silicone resins, ester resins, and fluororesins.

[0143] Also, the resin constituting the resin-dispersed carrier is not particularly limited, and known resins can be used. For example, styrene-acrylic resins, polyester resins, fluororesins, phenol resins, and the like can be used.

[0144] The median diameter of the carrier on a volume basis is preferably in the range of 20 to 100 μm, and more preferably in the range of 20 to 60 μm. The median diameter of the carrier on a volume basis can typically be measured by a laser diffraction particle size distribution measuring device "HELOS" (manufactured by SYMPATEC) equipped with a wet disperser.

[0145] Preferred carriers include coated carriers using a silicone resin, a copolymer resin (graft resin) of organopolysiloxane and a vinyl monomer, or a polyester resin as the coating resin from the viewpoint of spent resistance. In particular, from the viewpoints of durability, environmental stability resistance, and spent resistance, coated carriers coated with a resin obtained by reacting a copolymer resin (graft resin) of organopolysiloxane and a vinyl monomer with isocyanate are preferably mentioned.

[0146] 2. Method for Manufacturing Toner for Developing Electrostatic Charge Image The method for manufacturing a toner for developing an electrostatic charge image according to the present invention is a method for manufacturing a toner for developing an electrostatic charge image for manufacturing the toner for developing an electrostatic charge image, characterized by having a step of dispersing the photosensitizer in a single molecular state.

[0147] Regarding the method for manufacturing a general toner for developing an electrostatic charge image, there is a method (conventional grinding method) in which a binder resin and a pigment are dissolved in a soluble solvent and then the solvent is removed and incorporated into the binder resin. The ground toner manufactured by this method is manufactured through a grinding and classification process after mixing and melt-kneading a binder resin and a pigment, so the pigment is incorporated into the toner as aggregates.

[0148] There is also a method (conventional polymerization method) in which a binder resin monomer in which a pigment is previously dissolved is polymerized and polymerized fine particles in a state where the pigment is dissolved are used. Also in the case of the polymerized toner manufactured by this method, the polymerized binder resin particles and the pigment dispersion are associated for manufacturing, and the pigment is incorporated into the toner as aggregates.

[0149] The toner for developing an electrostatic charge image according to the present invention is preferably manufactured by a manufacturing method having a step of dispersing the photosensitizer in a single molecular state, rather than the above-described conventional manufacturing method.

[0150] In order to incorporate the photosensitizer into the toner for developing an electrostatic charge image in a single molecular state, the aggregated solid-state pigment is dissolved in a solvent or resin to be converted into a single molecular state, and then incorporated into the binder resin in a single molecular state, or metal oxide fine particles carrying the photosensitizer are produced, and the photosensitizer is incorporated into the toner particles or contained in an external additive and adhered to the surface of the toner matrix particles.

[0151] Specifically, the following methods can be mentioned. (1) A method (grinding method using the method of the present invention) in which a binder resin and a photosensitizer are dissolved in a soluble solvent and then the solvent is removed to incorporate the photosensitizer in a single molecular state into the binder resin. (2) A method of polymerizing a binder resin monomer in which a photosensitizer is previously dissolved and using polymer fine particles in a state where the photosensitizer in a single molecular state is dissolved (a polymerization method using the method of the present invention). (3) A method of producing metal oxide fine particles supporting a photosensitizer in which a photosensitizer molecule having a reactive group and soluble in a solvent is bonded or adsorbed in a single molecular state on the surface of the metal oxide fine particles, and incorporating the metal oxide particles as a whole into the toner particles during the production of the toner base particles or containing the metal oxide particles in an external additive and attaching them to the surface of the toner base particles (a method of the present invention other than the above method).

[0152] Among the above methods, as a method for producing the toner for electrostatic charge image development of the present invention, in consideration of the need to obtain a toner for electrostatic charge image development having a small particle size in order to achieve high image quality, it is preferable to use the method (2) or (3) from the viewpoints of production cost and production stability.

[0153] (An example of the toner production method: Production method 1) The method for producing a toner by the method (1) is composed of known steps [resin fine particle production step], [mixing step], [toner particle production step: kneading, pulverizing, and classification step], and [external additive treatment step], etc. In the [mixing step] among these steps, a method of producing toner particles by adding a photosensitizer in a state where singlet oxygen can be generated.

[0154] (An example of the toner production method: Production method 2) The method for producing a toner by the method (2) is to mix a dispersion of fine particles obtained by polymerizing a binder resin monomer in which a photosensitizer is dissolved in a state where singlet oxygen can be generated in advance, and a dispersion of coloring agent fine particles, and if necessary, also mix dispersions of other toner components for electrostatic charge image development such as a release agent. At that time, while taking the balance between the repulsive force on the surface of the fine particles due to pH adjustment and the aggregating force due to the addition of a flocculant composed of an electrolyte, the fine particles are slowly aggregated, and while controlling the average particle size and particle size distribution, aggregation is carried out, and at the same time, by heating and stirring, fusion between the fine particles is carried out to control the shape, thereby producing toner particles.

[0155] As these resin fine particles, a structure of two or more layers composed of binder resins having different compositions can also be adopted. In this case, a polymerization initiator and a polymerizable monomer are added to a dispersion of first resin fine particles prepared by an emulsion polymerization treatment (first-stage polymerization) according to a conventional method, and a method of subjecting this system to a polymerization treatment (second-stage polymerization) can be adopted. For example, the manufacturing process when obtained by the above method is composed of the following steps.

[0156] 〔Resin Fine Particle Dispersion Preparation Step〕 A photosensitizer is dissolved in a binder resin in a state where singlet oxygen can be generated in advance, and a mold release agent, a charge control agent, and other toner particle constituent materials are dissolved or dispersed in the polymerizable monomer to form the binder resin, thereby preparing a polymerizable monomer solution. This is added to an aqueous medium, mechanical energy is applied to form oil droplets, and then a polymerization reaction is carried out in the oil droplets by radicals from a water-soluble radical polymerization initiator to obtain a dispersion of resin fine particles carrying a photosensitizer.

[0157] As a method of incorporating a mold release agent into toner particles, a method of configuring binder resin fine particles to contain a mold release agent, or a method of adding a dispersion liquid in which mold release agent fine particles are dispersed in an aqueous medium in the salting-out, aggregation, and fusion steps for forming toner particles, and salting out, aggregating, and fusing the binder resin fine particles, the colorant fine particles, and the mold release agent fine particles, etc. can be mentioned, and these methods may be combined.

[0158] As a method of incorporating a charge control agent into toner particles, the same methods as those for incorporating the mold release agent shown above can be mentioned.

[0159] In the step of preparing the resin fine particle dispersion liquid, the binder resin fine particles in the dispersion liquid prepared are preferably in the range of 50 to 300 nm in median diameter based on volume.

[0160] In the step of preparing the resin fine particle dispersion liquid, in order to stably disperse the fine particles in the aqueous medium, a surfactant may be added to the aqueous medium. As such a surfactant, various conventionally known anionic surfactants, cationic surfactants, nonionic surfactants, etc. can be used.

[0161] The disperser for performing oil droplet dispersion by mechanical energy is not particularly limited, and examples include a stirring device "Clear Mix" (manufactured by M Technique Co., Ltd.) equipped with a high-speed rotating rotor, an ultrasonic disperser, a mechanical homogenizer, Manton Gorin, and a pressure type homogenizer.

[0162] The above-mentioned "aqueous medium" refers to a medium composed of 50 to 100% by mass of water and 0 to 50% by mass of a water-soluble organic solvent.

[0163] Examples of the water-soluble organic solvent include methanol, ethanol, isopropanol, butanol, acetone, methyl ethyl ketone, and tetrahydrofuran, and an alcohol-based organic solvent that does not dissolve the resulting resin is preferred.

[0164] 〔Step of preparing the colorant dispersion liquid〕 A step of obtaining a dispersion liquid of colorant fine particles in which colorant fine particles containing a colorant are dispersed in an aqueous medium.

[0165] In the step of preparing the colorant dispersion liquid, a colorant compound is added to the aqueous medium, and mechanical energy is applied thereto to prepare a dispersion liquid of colorant fine particles in which the colorant fine particles are dispersed in the aqueous medium.

[0166] In the process of preparing the colorant dispersion, in order to stably disperse the fine particles in the aqueous medium, a surfactant may be added to the aqueous medium. As such a surfactant, various conventionally known anionic surfactants, cationic surfactants, nonionic surfactants, etc. can be used.

[0167] The colored fine particles in the dispersion prepared in the process of preparing the colorant dispersion preferably have a volume-based median diameter in the range of 20 to 1000 nm, more preferably in the range of 20 to 140 nm, and particularly preferably in the range of 30 to 100 nm. As a method for controlling the volume-based median diameter of the colored fine particles within the range of 10 to 500 nm, there is a control method such as adjusting the magnitude of the mechanical energy described above.

[0168] 〔Toner particle formation step〕 A salting-out, aggregation, and fusion step of forming toner particles by adding a flocculant to the aqueous medium in which the binder resin fine particles and the colored fine particles are present and adjusting the temperature to cause salting-out to proceed while performing aggregation and fusion.

[0169] 〔Filtration and washing step〕 A step of filtering the toner particles from the aqueous medium and removing surfactants and the like from the toner particles.

[0170] 〔Drying step〕 A step of drying the washed toner particles.

[0171] 〔External additive addition step〕 A step of adding an external additive to the dried toner particles.

[0172] (An example of a toner manufacturing method: Manufacturing method 3) The method for manufacturing toner by the method of (3) is composed of the same steps as the manufacturing method of (2), except that the photosensitizer-supported metal oxide fine particles capable of generating singlet oxygen produced by the following [photosensitizer-supported metal oxide production step], which is different from the above [external additive addition step], are added to the toner particles together with the external additive added in the above [external additive addition step].

[0173] [Photosensitizer-Supported Metal Oxide Production Step] A step of preparing a photosensitizer-supported metal oxide fine particle by preliminarily putting metal oxide particles and a photosensitizer capable of generating singlet oxygen in a soluble solvent, mixing them, then heating and refluxing to prepare a reaction solution, and further subjecting the solid obtained by filtering and washing this reaction solution to vacuum drying.

[0174] (Particle size) The average particle size of the toner base particles contained in the electrostatic charge image developing toner of the present invention is preferably in the range of 4 to 10 μm, more preferably in the range of 6 to 9 μm, for example, in terms of the volume-based median diameter.

[0175] When the volume-based median diameter is within the above range, the transfer efficiency is increased, the halftone image quality is improved, and the image quality of thin lines and dots is improved. This average particle size can be controlled by the concentration of the aggregating agent (salting-out agent) used, the addition amount of the organic solvent, the fusing time, and the composition of the polymer.

[0176] The volume-based median diameter of the toner base particles is measured and calculated using a measuring device in which a computer system for data processing (manufactured by Beckman Coulter) is connected to a "Coulter Counter Multisizer 3" (manufactured by Beckman Coulter).

[0177] Specifically, 0.02 g of toner is added to 20 mL of a surfactant solution (for example, a surfactant solution obtained by diluting a neutral detergent containing a surfactant component 10 times with pure water for the purpose of dispersing the toner) and allowed to blend.

[0178] Thereafter, a toner dispersion is prepared by performing ultrasonic dispersion for 1 minute, and this toner dispersion is pipetted into a beaker containing "ISOTON II" (manufactured by Beckman Coulter) in a sample stand until the display concentration of the measuring device reaches 8%.

[0179] By setting the concentration to the above value, reproducible measurement values can be obtained. Then, in the measuring device, the number of measured particles is set to 25,000, the aperture diameter is set to 100 μm, the frequency values are calculated by dividing the measurement range of 2 to 60 μm into 256 segments, and the particle diameter at which 50% of the particles from the larger volume integration fraction is defined as the volume-based median diameter.

[0180] (Average circularity) Regarding each toner particle constituting the toner for electrostatic charge image development of the present invention, from the viewpoint of improving transfer efficiency, the average circularity calculated from the formula (circularity = circumference of a circle obtained from the equivalent circle diameter / circumference of the particle projection image) is preferably in the range of 0.930 to 1.000, more preferably in the range of 0.950 to 0.995.

[0181] 3. Image forming method The image forming method of the present invention is an image forming method using the toner for electrostatic charge image development, characterized by performing dot formation independently of the image portion. Since singlet oxygen is a gas and diffuses also to the range other than the printing portion (non-image portion), in the image forming method using the toner for electrostatic charge image development of the present invention, the antibacterial and antiviral effects can be exerted also on the non-image portion by the image forming method that performs dot formation independently of the image portion. Further, even if isolated dots with a diameter of 60 μm or less, which is a size that cannot be visually recognized, are printed, the effect can be exhibited.

[0182] (Calculation of the diffusion distance of singlet oxygen and the printing rate for exerting antibacterial and antiviral effects) Singlet oxygen 1 The diffusion distance X of O2 is expressed by the following formula.

[0183] Formula X 2 = 2Dt (In the above formula, X[m] represents the diffusion distance of singlet oxygen, D[m 2 / s] represents the diffusion coefficient of singlet oxygen, and t[s] represents the lifetime of the diffusing singlet oxygen.)

[0184] When an image is formed using the toner for electrostatic charge image development of the present invention, singlet oxygen diffuses from the printing portion up to several hundred millimeters 1 O2 will diffuse.

[0185] The singlet oxygen contained in the photosensitizer used in the toner for electrostatic charge image development of the present invention is premised to be used in the atmosphere. Its diffusion distance depends on humidity, and in a low-humidity environment, the antibacterial and antiviral effects spread at a lower printing rate.

[0186] Regarding singlet oxygen molecules that perform Brownian motion in the atmosphere, when citing the numerical values of a reported example with a diffusion coefficient of 2×10 -5 [m 2 / s] and a lifetime of the diffusing singlet oxygen of 62×10 -3 [s] at a humidity of 50%, from the above formula, the square of the diffusion distance of singlet oxygen (X 2 ) is 2×(2×10 -5 )×(62×10 -3 ) = 2.48×10 -6 [m 2 = 2.48[mm 2 , and the diffusion distance X can be derived as approximately 1.57[mm] = 1570[μm].

[0187] (Uses and Advantages of the Image Forming Method) When an image is formed using the toner for electrostatic charge image development of the present invention, the generated singlet oxygen can diffuse at least in units of millimeters. For example, if the diffusion radius of singlet oxygen is set to the diffusion distance 1.57≒1.5[mm] derived above, if toner particles are present at intervals of 3 mm, it can be calculated that the generated singlet oxygen can diffuse approximately over the entire recording medium surface. Note that the toner particles present on the recording medium do not necessarily have to be the toner particles that form dots, and for example, even if they are fog toner particles or the like, they can exhibit antibacterial and antiviral effects. Considering the results of the above calculation, when assuming an environment with a humidity of 50% and a resolution of 1200 dpi independently of the image area, if the electrostatic charge image developing toner of the present invention is used in the form of a clear toner and full-surface printing with a printing rate of about 0.01% at equal intervals is performed, it is possible to form an image with an antibacterial and antiviral effect applied to the entire surface regardless of the image pattern.

[0188] Furthermore, according to the above image forming method, there is an advantage that the influence of light transmission inhibition by the toner colorant can be ignored.

[0189] In the case of a 5-drum / 6-drum machine, without changing the 4-color (CMYK) developer, by using the electrostatic charge image developing toner of the present invention in the form of a clear toner and simply adding its developing device to the 5-drum / 6-drum machine, it can be applied to the device.

[0190] 4. Image Forming System The image forming system of the present invention uses the aforementioned electrostatic charge image developing toner and image forming method of the present invention, and includes a charging means for the photoreceptor, a latent image forming means, a developing means, a transfer means, and a cleaning means. Preferably, the image forming system further includes a fixing means for fixing the toner image transferred to the transfer material. That is, it is a system for forming an image using the electrostatic charge image developing toner of the present invention in an electrophotographic image forming apparatus (hereinafter, also simply referred to as an "image forming apparatus") capable of implementing the above respective means according to the present invention. Hereinafter, each means of the image forming system of the present invention will be described.

[0191] (Charging Means) The charging means is a means for charging the photoreceptor by applying a uniform potential to the photoreceptor. In this charging means, the photoreceptor is charged by using a contact charging roller.

[0192] (Latent image forming means) The latent image forming means is a means for forming an electrostatic latent image corresponding to an image by exposing a photoreceptor having a uniform potential applied thereto by a charging means based on an image signal. As the latent image forming means, one composed of an LED in which light emitting elements are arranged in an array in the axial direction of the photoreceptor and a pixel element, or a laser optical system or the like is used.

[0193] (Developing means) The developing means is a means for developing an electrostatic latent image with a dry developer containing the toner for developing an electrostatic charge image of the present invention to form a toner image. The formation of the toner image is performed using a developing means including a stirrer for charging the toner by frictionally stirring the toner-containing dry developer and a rotatable magnetic roller. Specifically, in the developing means, for example, the toner and the carrier are mixed and stirred, and the toner is charged by the friction at that time, and is held on the surface of the rotating magnetic roller to form a magnetic brush. Since the magnetic roller is disposed near the photoreceptor, a part of the toner constituting the magnetic brush formed on the surface of the magnetic roller moves to the surface of the photoreceptor by an electric attractive force. As a result, the electrostatic latent image is developed with the toner to form a toner image on the surface of the photoreceptor.

[0194] (Transfer means) In the transfer means, the toner image is transferred to a transfer material. The transfer of the toner image to the transfer material is performed by peeling and charging the toner image to the transfer material. As the transfer means, for example, a corona transfer device by corona discharge, a transfer belt, a transfer roller, or the like can be used. Further, the transfer means can be performed by, for example, using an intermediate transfer member, primary-transferring the toner image onto the intermediate transfer member, and then secondary-transferring this toner image onto the transfer material, or directly transferring the toner image formed on the photoreceptor onto the transfer material. The transfer material is not particularly limited, and examples thereof include ordinary paper from thin paper to thick paper, coated printing paper such as fine paper, art paper, or coated paper, commercially available Japanese paper or postcard paper, plastic film for OHP, cloth, and various others.

[0195] (Fixing means) The fixing means is a means for fixing the transfer material onto which the toner image has been transferred by, for example, nipping and conveying it to a fixing nip portion provided between a heated fixing rotator and a pressure member and thermally fixing it.

[0196] (Cleaning means) On the photoreceptor after the transfer means, there is toner that has not been used for image formation or has remained without being transferred. In the cleaning means, for example, the toner is removed by a blade or the like that is provided in contact with the photoreceptor and scrapes the surface of the photoreceptor.

[0197] 5. Image forming apparatus An example of an image forming apparatus capable of implementing the image forming system of the present invention will be described below with reference to the drawings.

[0198] FIG. 3 is a schematic cross-sectional view showing the configuration in an example of the image forming apparatus according to the present invention. This image forming apparatus 100 is called a tandem type color image forming apparatus and includes four sets of image forming units (image forming units) 10Y, 10M, 10C, and 10Bk arranged vertically in series, an intermediate transfer body unit 7, paper feeding means 21, and fixing means 24. On the upper part of the main body 100A of the image forming apparatus 100, an original image reading device SC is arranged.

[0199] The intermediate transfer body unit 7 includes an endless belt-shaped intermediate transfer body 70 that is rotatable by winding rollers 71, 72, 73, and 74, primary transfer rollers 5Y, 5M, 5C, 5Bk, and cleaning means 6b.

[0200] The four sets of image forming units 10Y, 10M, 10C, and 10Bk each have a drum-shaped photoreceptor 1Y, 1M, 1C, and 1Bk at the center, and a charging means 2Y, 2M, 2C, and 2Bk, a latent image forming means 3Y, 3M, 3C, and 3Bk, a rotating developing means 4Y, 4M, 4C, and 4Bk, and a cleaning means 6Y, 6M, 6C, and 6Bk for cleaning the photoreceptors 1Y, 1M, 1C, and 1Bk arranged around the photoreceptors.

[0201] The image forming units 10Y, 10M, 10C, and 10Bk each form a toner image of yellow, magenta, cyan, and black, respectively. In the image forming system of the present invention, the charging means, the latent image forming means, and the developing means are means for forming a toner image on the photoreceptor. In the image forming apparatus 100, the image forming units 10Y, 10M, 10C, 10Bk use the photoreceptors 1Y, 1M, 1C, 1Bk and the toner for electrostatic charge image development of the present invention and are performed as follows. Note that the toner can be mixed with the carrier as described above and used as a two-component developer.

[0202] The image forming units 10Y, 10M, 10C, 10Bk have the same configuration except that the colors of the toner images formed on the photoreceptors 1Y, 1M, 1C, 1Bk are different. The image forming unit 10Y will be described in detail as an example.

[0203] The image forming unit 10Y arranges a charging means 2Y, a latent image forming means 3Y, a developing means 4Y, and a cleaning means 6Y around the photoreceptor 1Y which is an image forming body, and forms a yellow (Y) toner image on the photoreceptor 1Y. In the present embodiment, at least the photoreceptor 1Y, the charging means 2Y, the developing means 4Y, and the cleaning means 6Y of the image forming unit 10Y are provided so as to be integrated.

[0204] The charging means 2Y is a means for applying a uniform potential to the photoreceptor 1Y. In the present invention, examples of the charging means include a contact roller charging method.

[0205] The latent image forming means 3Y is a means for performing exposure on the photoreceptor 1Y given a uniform potential by the charging means 2Y based on an image signal (yellow) to form an electrostatic latent image corresponding to the yellow image. As this latent image forming means 3Y, one composed of an LED in which light emitting elements are arrayed in an array in the axial direction of the photoreceptor 1Y and a pixel element, or a laser optical system or the like is used.

[0206] The developing means 4Y includes, for example, a developing sleeve that incorporates a magnet and holds a two-component developer and rotates, and a voltage applying device that applies a DC and / or AC bias voltage between the photoreceptor 1Y and this developing sleeve.

[0207] The cleaning means 6Y is composed of a cleaning blade provided so that the tip abuts on the surface of the photoreceptor 1Y and a brush roller provided upstream of this cleaning blade and contacting the surface of the photoreceptor 1Y. The cleaning blade has a function of removing residual toner attached to the photoreceptor 1Y and a function of scraping the surface of the photoreceptor 1Y.

[0208] The brush roller has a function of removing residual toner attached to the photoreceptor 1Y, a function of recovering the residual toner removed by the cleaning blade, and a function of scraping the surface of the photoreceptor 1Y. That is, the brush roller contacts the surface of the photoreceptor 1Y, and at the contact portion, it rotates in the same direction as the traveling direction of the photoreceptor 1Y to remove residual toner and paper powder on the photoreceptor 1Y and convey and recover the residual toner removed by the cleaning blade. In this way, by combining the toner for electrostatic charge image development of the present invention, a high-quality image that can exert an antibacterial and antiviral effect even on non-image areas can be stably formed.

[0209] In an image forming system using the image forming apparatus 100, the transfer means for transferring the toner image formed on the photoreceptor to a transfer material uses an intermediate transfer member, and after primarily transferring the toner image onto the intermediate transfer member, transfers this toner image onto the transfer material in a secondary transfer manner, as described below.

[0210] The toner images of respective colors formed by the image forming units 10Y, 10M, 10C, and 10Bk are sequentially transferred onto the rotatable endless belt-shaped intermediate transfer member 70 included in the intermediate transfer member unit 7 by primary transfer rollers 5Y, 5M, 5C, and 5Bk as primary transfer means, and a combined color image is formed. The endless belt-shaped intermediate transfer member 70 is a semiconductive endless belt-shaped second image carrier wound by a plurality of rollers 71, 72, 73, and 74 and rotatably supported.

[0211] The color image combined on the endless belt-shaped intermediate transfer member 70 is then transferred to a transfer material P (an image support that supports the final fixed image: for example, plain paper, a transparent sheet, etc.). Specifically, the transfer material P housed in the paper feed cassette 20 is fed by the paper feed means 21, and is conveyed to a secondary transfer roller 5b as secondary transfer means via a plurality of intermediate rollers 22A, 22B, 22C, 22D and a registration roller 23. Then, by the secondary transfer roller 5b, the color image is batch-transferred (secondary transfer) from the endless belt-shaped intermediate transfer member 70 onto the transfer material P. The transfer material P onto which the color image has been transferred is subjected to a fixing process by the fixing means 24, is sandwiched by the paper discharge rollers 25, and is placed on an external paper discharge tray 26.

[0212] The fixing means 24 includes, for example, a heating roller having a heat source inside, and a pressure roller provided in a state of being pressed against the heating roller so that a fixing nip portion is formed thereon, and is of a heat roller fixing type.

[0213] On one hand, after transferring the color image onto the transfer material P by the secondary transfer roller 5b as the secondary transfer means, the endless belt-shaped intermediate transfer body 70 from which the transfer material P has been separated by curvature has the residual toner removed by the cleaning means 6b.

[0214] During the image formation process, the primary transfer roller 5Bk is always in contact with the photoreceptor 1Bk. The other primary transfer rollers 5Y, 5M, and 5C are in contact with the corresponding photoreceptors 1Y, 1M, and 1C only during color image formation. The secondary transfer roller 5b is in contact with the endless belt-shaped intermediate transfer body 70 only when the transfer material P passes through here and secondary transfer is performed.

[0215] Also, in the image forming apparatus 100, a housing 8 composed of the image forming units 10Y, 10M, 10C, 10Bk and the intermediate transfer body unit 7 can be pulled out from the apparatus main body 100A via the support rails 82L and 82R.

[0216] Although the image forming system in a color laser printer has been described using the image forming apparatus 100 shown in FIG. 3, the image forming system of the present invention is similarly applicable to a monochrome laser printer or a copying machine. Also, a light source other than a laser, for example, an LED light source, may be used as the exposure light source.

[0217] Although the embodiments of the present invention have been described above, the present invention is not limited to the above-described aspects, and various modifications can be made.

[0218] 6. Output The output of the present invention is an output formed using an electrostatic charge image developing toner, and is characterized by being formed using the electrostatic charge image developing toner. The output formed using the electrostatic charge image developing toner of the present invention is preferable from the viewpoint that the antibacterial and antiviral effects can be preferably exhibited.

[0219] (Recording Medium) The recording medium used for forming the output of the present invention is not particularly limited, and examples include ordinary paper from thin paper to thick paper, coated printing paper such as fine paper, art paper, or coated paper, water-soluble paper, commercially available Japanese paper or postcard paper, plastic films, cloth, leather, and various others, but are not limited thereto. Also, the color of the recording medium is not particularly limited.

Examples

[0220] Hereinafter, the present invention will be specifically described with reference to examples, but the present invention is not limited thereto. In the following examples, unless otherwise specified, the operations were carried out at room temperature (25 °C). Also, unless otherwise specified, “%” and “parts” respectively mean “mass %” and “parts by mass”.

[0221] A. Preparation of resin fine particle dispersion (A.1) Preparation of resin fine particle dispersion [LX-1] (A.1.1) First-stage polymerization: Preparation of latex Into a 5000 mL separable flask equipped with a stirrer, temperature sensor, condenser, and nitrogen inlet device, a surfactant solution (aqueous medium) prepared by dissolving 7.08 g of an anionic surfactant (sodium dodecylbenzenesulfonate: SDS) in 2760 g of ion-exchanged water was charged, and while stirring at a stirring speed of 230 rpm under a nitrogen stream, the internal temperature was raised to 80 °C.

[0222] On the other hand, next, a mixture consisting of 115.1 g of styrene, 42.0 g of n-butyl acrylate, 10.9 g of methacrylic acid, 0.1 mass % of a phthalocyanine compound (F-13) as a photosensitizer, and 72.0 g of a compound represented by the following formula (W) as a release agent with respect to these monomer components was heated to 80 °C and dissolved to prepare a first monomer solution. Formula (W): C{CH2OCO(CH2) 20 CH3}4

[0223] Using a mechanical disperser with a circulation path, the first monomer solution (80 °C) was mixed and dispersed in the surfactant solution (80 °C) to prepare a dispersion of emulsified particles (oil droplets) having a uniform dispersed particle size. Next, an initiator solution prepared by dissolving 0.84 g of a polymerization initiator (potassium persulfate: KPS) in 200 g of ion-exchanged water was added to this dispersion, and polymerization (first-stage polymerization) was carried out by heating and stirring this system at 80 °C for 3 hours to prepare a latex.

[0224] (A.1.2) Second-stage polymerization Next, a solution prepared by dissolving 8.00 g of a polymerization initiator (potassium persulfate: KPS) and 10.0 g of 2-chloroethanol as a water-soluble chain transfer agent in 240 g of ion-exchanged water was added to this latex. After 15 minutes had passed, a second monomer solution consisting of 383.6 g of styrene, 140.0 g of n-butyl acrylate, and 36.4 g of methacrylic acid was added dropwise over 126 minutes at 80 °C. After completion of the dropwise addition, polymerization (second-stage polymerization) was carried out by heating and stirring for 60 minutes, and then the mixture was cooled to 40 °C to prepare a resin fine particle dispersion [LX-1].

[0225] [Measurement and Observation of Absorption Spectrum] Next, an appropriate amount of this resin fine particle dispersion was sampled, coated on a PET film using a spin coater, and dried. When the absorption spectrum of the obtained solid film sample was measured, a sharp absorption peak was observed at 665 nm. Furthermore, when the solution absorption spectrum of the solution obtained by dissolving this film sample in THF was measured, an absorption peak was observed at 665 nm, which was the same as that of the solid film sample. Therefore, it was confirmed that the phthalocyanine compound (F-13) used as a photosensitizer exists in a single-molecule state.

[0226] (A.2) Preparation of Resin Fine Particle Dispersions [LX-2] to [LX-17] (First-stage polymerization: Preparation of latex) Resin microparticle dispersions [LX-2] to [LX-17] were prepared in the same manner as the resin microparticle dispersion [LX-1], except that the type and content of the photosensitizer were changed as shown in Table III. Also, in the measurement and observation of the absorption spectrum, the presence or absence of the monomolecular state was confirmed by performing the measurement in the same manner as for the resin microparticle dispersion [LX-1], and the results are shown in Table III.

[0227] [Table 3]

[0228] B. Preparation of colorant dispersion (B.1) Preparation of colorant dispersion [1] (cyan) 11.5 parts by mass of sodium n-dodecyl sulfate was stirred and dissolved in 160 parts by mass of ion-exchanged water. While continuing stirring, 10 parts by mass of a phthalocyanine compound (F-13) as a pigment was gradually added, and then the colorant dispersion [1] in which the colorant was dispersed was prepared by performing a dispersion treatment using a mechanical disperser "ClearMix W Motion CLM-0.8" (manufactured by M Technique Co., Ltd.).

[0229] (Measurement and observation of particle diameter and absorption spectrum) The particle diameter of the colorant particles in this colorant dispersion [1] was 89 nm in terms of the volume-based median diameter. Also, the absorption spectrum measured by coating this colorant dispersion [1] on a PET film showed a broad absorption spectrum, and the absorption maximum peak thereof was 576 nm, and no distinct peak was observed at 665 nm of the solution absorption. Therefore, it was confirmed that the phthalocyanine compound (F-13) used as the pigment was present not in the monomolecular state but in the aggregated state. The volume-based median diameter of the colorant fine particles in the colorant dispersion was measured under the following measurement conditions using "MICROTRAC UPA-150" (manufactured by HONEYWELL).

[0230] <Measurement Conditions> · Sample refractive index: 1.59 · Sample specific gravity: 1.05 (in terms of spherical particles) · Solvent refractive index: 1.33 · Solvent viscosity: 0.797 [mPa·s] at 30°C and 1.002 [mPa·s] at 20°C · Zero point adjustment: Fill the measurement cell with ion-exchanged water for adjustment.

[0231] (B.2) Preparation of Colorant Dispersion Liquid [2] (Cyan) The colorant dispersion liquid [2] (cyan) was prepared in the same manner as the preparation of the colorant dispersion liquid [1] (cyan) in (B.1), except that the pigment was changed to a phthalocyanine compound (F-9).

[0232] [Measurement and Observation of Particle Size and Absorption Spectrum] The particle size of the colorant particles in this colorant dispersion liquid [2] (cyan) was 89 nm in terms of the volume-based median diameter. In addition, the absorption spectrum measured by coating this colorant dispersion liquid [2] on a PET film showed a broad absorption spectrum, and its absorption maximum peak was 576 nm, and no distinct peak was observed at 665 nm of the solution absorption. Therefore, it was confirmed that the phthalocyanine compound (F-9) existed as an aggregated state rather than a single molecular state as a pigment. Note that the volume-based median diameter of the colorant fine particles in the colorant dispersion liquid was measured under the same measurement conditions as those of the colorant dispersion liquid [1].

[0233] (B.3) Preparation of Colorant Dispersion Liquid [3] (Black) The colorant dispersion liquid [3] (black) was prepared in the same manner as the preparation of the colorant dispersion liquid [1] (cyan) in (B.1), except that 9 parts by mass of sodium n-dodecyl sulfate was used and the pigment was changed to 42 parts by mass of carbon black (Regal 330R, manufactured by Cabot Corporation).

[0234] [Measurement and Observation of Particle Size and Absorption Spectrum] The median diameter of the pigment particles in this pigment dispersion liquid [3] (black) was 25 nm on a volume basis. In addition, the absorption spectrum measured by applying this pigment dispersion liquid [3] to a PET film showed a broad absorption spectrum, confirming that the carbon black existed in an aggregated state rather than in a single-molecule state. The median diameter of the pigment fine particles in the pigment dispersion liquid was measured under the same measurement conditions as those for the pigment dispersion liquid [1].

[0235] C. Preparation of Photosensitizer-Supported Silica Fine Particles [Si-1] 5 g of silica fine particles (SiO2, OX-50 manufactured by Nippon Aerosil Co., Ltd., surface area 55 m 2 , average particle diameter 21 nm), 0.05 g of a phthalocyanine compound (F-3), and 200 mL of toluene were mixed and heated under reflux for 2 hours. This reaction solution was filtered while hot, further washed with hot toluene, and then washed with methanol. The obtained solid was dried under vacuum to prepare photosensitizer-supported silica fine particles [Si-1].

[0236] D. Preparation of Each Toner (D.1) Preparation of Clear Toner (D.1.1) Preparation of Toner 1 1250 g of the resin fine particle dispersion liquid [LX-1] and 2000 g of ion-exchanged water were placed in a 5-liter four-necked flask equipped with a temperature sensor, a condenser, a nitrogen introduction device, and a stirring device, and stirred to prepare a stock solution. After adjusting the internal temperature of this stock solution to 30°C, a 5 mol / L aqueous sodium hydroxide solution was added to adjust the pH to 10.0. Next, an aqueous solution prepared by dissolving 52.6 g of magnesium chloride hexahydrate in 72 g of ion-exchanged water was added dropwise at 30°C over 10 minutes with stirring. After leaving it for 3 minutes, the temperature was raised, and this system was heated to 90°C over 6 minutes (heating rate = 10°C / min). In that state, the average particle size of the aggregated particles was measured using a "Coulter Multisizer TA-III" (manufactured by Beckman Coulter, Inc.). When the volume-based median diameter reached 6.5 μm, an aqueous solution prepared by dissolving 115 g of sodium chloride in 700 g of ion-exchanged water was added to stop particle growth. Further, fusion was continued by heating and stirring at a liquid temperature of 90 °C ± 2 °C for 6 hours. Thereafter, it was cooled to 30 °C at a rate of 6 °C / min, hydrochloric acid was added to adjust the pH to 2.0, and stirring was stopped. The generated aggregated particles were subjected to solid-liquid separation, and washing with 15 liters of ion-exchanged water was repeated 4 times. Thereafter, they were dried with warm air at 40 °C to obtain clear toner particles [TP-1]. To the powder composed of these clear toner particles [TP-1], 1% by mass of hydrophobic silica (number-average primary particle diameter = 12 nm, degree of hydrophobization = 68) and 1% by mass of hydrophobic titanium oxide (number-average primary particle diameter = 20 nm, degree of hydrophobization = 63) were added and mixed using a "Henschel mixer" (manufactured by Mitsui Miike Chemical Machinery Co., Ltd.). Thereafter, toner 1 was produced by removing coarse particles using a sieve with a mesh size of 45 μm.

[0237] (D.1.2) Preparation of Toners 2 to 10 Toners 2 to 10 were produced in the same manner as the production of toner 1, except that the type of the resin fine particle dispersion was changed as shown in Table III.

[0238] (D.1.3) Preparation of Toner 13 A resin fine particle dispersion (LX-13) was prepared in the same manner as the resin fine particle dispersion (LX-1), except that the photosensitizer was excluded. Otherwise, toner particles [TP-13] were obtained in the same manner as the preparation of the resin fine particle dispersion (LX-1). To these toner particles [TP-13], 0.6% by mass of hydrophobic silica (number-average primary particle diameter = 12 nm, degree of hydrophobization = 68), 0.8% by mass of hydrophobic titanium oxide (number-average primary particle diameter = 20 nm, degree of hydrophobization = 63), and 0.6% by mass of the above-mentioned photosensitizer-supported silica fine particles [Si-1] were added and mixed using a "Henschel mixer" (manufactured by Mitsui Miike Chemical Machinery Co., Ltd.). After that, toner 13 was produced by removing coarse particles using a sieve with a mesh opening of 45 μm.

[0239] (D.1.4) Production of toner 15 (Comparative Example 1) A resin fine particle dispersion (LX-15) was prepared in the same manner as the resin fine particle dispersion (LX-1), except that the photosensitizer was excluded. Otherwise, toner particles [TP-15] were obtained in the same manner as the preparation of the resin fine particle dispersion (LX-1). To the powder composed of these toner particles [TP-15], 1% by mass of hydrophobic silica (number average primary particle diameter = 12 nm, degree of hydrophobization = 68) and 1% by mass of hydrophobic titanium oxide (number average primary particle diameter = 20 nm, degree of hydrophobization = 63) were added and mixed using a "Henschel mixer" (manufactured by Mitsui Miike Chemical Machinery Co., Ltd.). After that, toner 15 was produced by removing coarse particles using a sieve with a mesh opening of 45 μm.

[0240] (D.1.5) Production of toner 18 A resin fine particle dispersion (LX-17) was prepared in the same manner as the resin fine particle dispersion (LX-1), except that the photosensitizer was 0.1% by mass of a phenalene compound (I-2). Otherwise, toner particles [TP-18] were obtained in the same manner as the preparation of the resin fine particle dispersion (LX-1). To the powder composed of these toner particles [TP-18], 1% by mass of hydrophobic silica (number average primary particle diameter = 12 nm, degree of hydrophobization = 68) and 1% by mass of hydrophobic titanium oxide (number average primary particle diameter = 20 nm, degree of hydrophobization = 63) were added and mixed using a "Henschel mixer" (manufactured by Mitsui Miike Chemical Machinery Co., Ltd.). After that, toner 18 was produced by removing coarse particles using a sieve with a mesh opening of 45 μm.

[0241] (D.2) Production of cyan toner (D.2.1) Production of toner 11 Cyan toner particles [CP-11] were obtained in the same manner as toner particles [TP-1], except that 165 g of a colorant dispersion [1] was put into the solution for mixing. To the powder composed of this cyan toner particle [CP-11], 1% by mass of hydrophobic silica (number average primary particle diameter = 12 nm, degree of hydrophobization = 68) and 1% by mass of hydrophobic titanium oxide (number average primary particle diameter = 20 nm, degree of hydrophobization = 63) were added and mixed using a "Henschel mixer" (manufactured by Mitsui Miike Chemical Machinery Co., Ltd.). Thereafter, toner 11 was produced by removing coarse particles using a sieve with a mesh opening of 45 μm.

[0242] (D.2.2) Production of toner 14 A resin fine particle dispersion (LX-14) was prepared in the same manner as the resin fine particle dispersion (LX-1) except that the photosensitizer was removed. Cyan toner particles [CP-14] were obtained in the same manner as the toner particles [TP-1] except that 165 g of the colorant dispersion [1] was put into the solution for mixing. To this cyan toner particle [CP-14], 0.6% by mass of hydrophobic silica (number average primary particle diameter = 12 nm, degree of hydrophobization = 68), 0.8% by mass of hydrophobic titanium oxide (number average primary particle diameter = 20 nm, degree of hydrophobization = 63), and 0.6% by mass of the above photosensitizer-supported silica fine particles [Si-1] were added and mixed using a "Henschel mixer" (manufactured by Mitsui Miike Chemical Machinery Co., Ltd.). Thereafter, toner 14 was produced by removing coarse particles using a sieve with a mesh opening of 45 μm.

[0243] (D.2.3) Production of toner 16 (Comparative Example 2) Cyan toner particles [CP-16] were obtained in the same manner as the toner particles [TP-1] except that 165 g of the colorant dispersion [2] was put into the solution for mixing. To this cyan toner particle [CP-16], 0.6% by mass of hydrophobic silica (number average primary particle diameter = 12 nm, degree of hydrophobization = 68), 0.8% by mass of hydrophobic titanium oxide (number average primary particle diameter = 20 nm, degree of hydrophobization = 63), and 0.6% by mass of the above photosensitizer-supported silica fine particles [Si-1] were added and mixed using a "Henschel mixer" (manufactured by Mitsui Miike Chemical Machinery Co., Ltd.). Thereafter, toner 16 was produced by removing coarse particles using a sieve with a mesh opening of 45 μm.

[0244] (D.3) Preparation of Black Toner (D.3.1) Preparation of Toner 12 Black toner particles [BP-12] were obtained in the same manner as toner particles [TP-1], except that 165 g of a colorant dispersion [3] was added to the solution for use in meetings. To the powder composed of these black toner particles [BP-12], 1% by mass of hydrophobic silica (number-average primary particle diameter = 12 nm, degree of hydrophobization = 68) and 1% by mass of hydrophobic titanium oxide (number-average primary particle diameter = 20 nm, degree of hydrophobization = 63) were added and mixed using a "Henschel mixer" (manufactured by Mitsui Miike Chemical Machinery Co., Ltd.). Thereafter, toner 12 was prepared by removing coarse particles using a sieve with a mesh size of 45 μm.

[0245] (D.3.2) Preparation of Toner 17 100 parts by mass of a polyester resin (weight-average molecular weight (Mw) 20,000), which is a condensate of bisphenol A-ethylene oxide adduct, terephthalic acid, and trimellitic acid, and 0.1 part by mass of a phthalocyanine compound (F-9) as a photosensitizer were dissolved by heating in toluene. After complete dissolution, toluene was removed to prepare a polyester resin [ground P] containing a photosensitizer in a monomolecular state. The obtained photosensitizer-containing polyester resin, 4 parts by mass of carbon black, 6 parts by mass of pentaerythritol tetrastearate as a release agent, and 1 part by mass of boron dibenzoate as a charge control agent were put into a "Henschel mixer" (manufactured by Mitsui Miike Mining Co., Ltd.), and the peripheral speed of the stirring blades was set to 25 m / sec and mixed for 5 minutes.

[0246] Next, the mixture was kneaded with a twin-screw extrusion kneader, coarsely pulverized with a hammer mill, then pulverized with a turbo mill (manufactured by Turbo Industry Co., Ltd.), and further subjected to fine classification treatment with an air classifier utilizing the Coandă effect to obtain black toner particles [BP-17] having a volume-based median diameter of 5.5 μm.

[0247] Next, 0.6 parts by mass of silica (average primary particle size: 12 nm) treated with hexamethylsilazane and 0.8 parts by mass of titanium dioxide (average primary particle size: 24 nm) treated with n-octylsilane were added to the powder of this toner particle [BP-17], and an external additive addition treatment was carried out using a "Henschel mixer" (manufactured by Mitsui Miike Mining Co., Ltd.) under the conditions of a peripheral speed of the stirring blade of 35 m / s, a treatment temperature of 35°C, and a treatment time of 15 minutes, thereby producing toner 17 which is a pulverized toner.

[0248] E. Preparation of Developer To each of the produced toners, ferrite carriers having a volume-based median diameter of 60 μm coated with a silicone resin were mixed so that the concentration of each toner became 6% by mass, thereby preparing a two-component developer.

[0249] F. Preparation of Electrophotographic Image (Evaluation Sample) and Method for Observing Phosphorescence Each of the produced toners was set in a full-color high-speed multifunction machine "bizhub C 6500" (manufactured by Konica Minolta), and under the conditions set at a fixing linear speed of 310 mm / min (about 65 sheets / min), on "POD Gloss Coat Paper 128 g / m 2 " (manufactured by Oji Paper Co., Ltd.), a patch image was formed at a toner adhesion amount of 4 g / m 2 .

[0250] When a sample was cut out from the above image and an attempt was made to detect the phosphorescence spectrum derived from singlet oxygen when the sample was irradiated with light using a spectrofluorophotometer EP-8700 (manufactured by JASCO Corporation), phosphorescence derived from singlet oxygen could be observed at around 1270 nm in the examples in Table III, but phosphorescence could not be observed in the comparative examples. The measurement was carried out under the following measurement conditions.

[0251] (Measurement Conditions) Measurement System EP-8700 (manufactured by JASCO Corporation) Measurement Mode Fluorescence (Monochromatic Light Monitor Ratio Calculation Method) Excitation wavelength range: Monochromatic light with a wavelength corresponding to the absorption maximum wavelength of the photosensitizer in the single-molecule or aggregated state having singlet oxygen generation ability (within the range of 350 to 800 nm) is irradiated for excitation Measurement interval: 5 nm Measurement wavelength range: 1200 to 1350 nm Data acquisition interval: 2 nm

[0252] Note that the measurement of the absorption maximum wavelength of the photosensitizer was performed by measuring the spectral absorption spectrum of a solution dissolved in tetrahydrofuran (THF).

[0253] G. Confirmation of coloring derived from the single-molecule absorption spectrum of the photosensitizer: Evaluation of the indicator property of singlet oxygen generation ability As described above, toner 1 is a clear toner containing a phthalocyanine dye in a single-molecule state, so it exhibits a blue color. In this state, singlet oxygen can be effectively generated.

[0254] When this toner 1 was irradiated with 665-nm monochromatic light in a toner irradiated with light for 8 hours under the condition of 1 SUN (100 mW / cm 2 ), a phosphorescence peak derived from singlet oxygen could be observed at around 1270 nm with a fluorometer, and the same blue color as before the light irradiation could be visually recognized.

[0255] On the other hand, when toner 1 was irradiated with 665-nm monochromatic light in a toner irradiated with light for 30 days under the condition of 1 SUN (100 mW / cm 2 ), the blue color was not visually recognized, and the absorption peak of the phthalocyanine dye when irradiated with 665-nm monochromatic light also disappeared. From the above, it can be said that presenting coloring derived from the single-molecule absorption spectrum of the photosensitizer can be used as an indicator of singlet oxygen generation ability.

[0256] H. Antibacterial and antiviral effects (H.1) Confirmation of antibacterial effect The confirmation of the antibacterial effect was carried out in accordance with JIS Z 2801:2010 (Antibacterial processed products - Antibacterial test method - Antibacterial effect). A 5 cm square sample was cut from the patch portion of the printed image prepared using the toner of each example and used as a specimen for the antibacterial test. Using this specimen, the viable cell count of Escherichia coli after 24 hours at 35°C was evaluated by the film adhesion method.

[0257] Note that Escherichia coli (ISO3301) was used as the test bacterium. To prepare the test bacterial solution, first, a normal broth solution was prepared by dissolving 5 g of meat extract, 10 g of peptone, and 5 g of sodium chloride in 1 L of distilled water. This broth solution was further diluted 500-fold with distilled water, and Escherichia coli was suspended in such a solution so that the number of bacteria per 1 mL was 1.0×10 6 cells. After dropping 0.5 mL of the bacterial solution onto this specimen, a polyethylene film was adhered and left at 35°C for 24 hours.

[0258] The bacteria adhering to this specimen and the coating film were poured into a sterilized petri dish using 9.5 mL of SCDLP medium (manufactured by Nippon Pharmaceutical Co., Ltd.). The viable cell count in 1 mL of this wash solution was measured by the agar plate dilution method using a standard agar medium for bacteria count measurement (manufactured by Nissui Pharmaceutical Co., Ltd.), and the sterilization rate was calculated to be 99.98%, indicating good antibacterial properties.

[0259] Note that the above antibacterial effect was confirmed to show good antibacterial properties under the criterion that the antibacterial property is considered good when the initial number of added bacteria defined by the film adhesion method decreases to one-thousandth or less in the above sample.

[0260] (H.2) Activity evaluation of each toner image (Evaluation method) From the above (H.1), it was shown that each toner of the present invention has good antibacterial properties. Therefore, this time, in order to compare the antibacterial effects of the toners of the examples and comparative examples, the magnitude of the discoloration action of the dye by singlet oxygen was compared by the following method as a substitute evaluation.

[0261] Image samples cut into various 5-cm angles were placed in a transparent petri dish, and a filter paper (5 mm × 5 mm) soaked with a 0.1% rubrene-alcohol solution was placed on top and sealed to obtain the samples of the examples and comparative examples.

[0262] Each of the above samples was left standing for 24 hours at room temperature under a fluorescent lamp of 1000 (lx). The filter paper was taken out of the petri dish, the dye concentration was measured, and the residual rate was determined from the ratio to the initial concentration. The evaluation criteria are shown below. Also, the results of each evaluation are shown in Table III.

[0263] (Evaluation Criteria) ◎ Residual rate less than 10% 〇 Residual rate 10% or more and less than 30% △ Residual rate 30% or more and less than 90% × Residual rate 90% or more

[0264] From the results in Table III, it is suggested that the toner of the present invention can change oxygen in the air into active species (such as singlet oxygen) even under weak light irradiation such as indoor light irradiation. Based on the results of the above evaluation experiments (H.1) and (H.2), it is presumed that there is an oxidation effect by singlet oxygen, that is, antiviral property, against viruses.

[0265] (H.3) Antiviral effect In addition, regarding the antiviral effect of singlet oxygen, it is also supported by the fact that the aqueous varnish: Lock3 (manufactured by Varcotec) using a photosensitizer similar to the phenalene derivative used in the examples according to the present invention has an antiviral effect, as demonstrated by a test conforming to ISO 21702 (antiviral).

Explanation of Reference Numerals

[0266] 100 Image forming apparatus 1A, 1B, 1Y, 1M, 1C, 1Bk Photoreceptor 2Y, 2M, 2C, 2Bk Charging means Exposure means for 3Y, 3M, 3C, 3Bk Development means for 4Y, 4M, 4C, 4Bk Primary transfer roller for 5Y, 5M, 5C, 5Bk Secondary transfer roller 5b Cleaning means for 6Y, 6M, 6C, 6Bk, 6b Intermediate transfer unit 7 Housing 8 Image forming unit for 10Y, 10M, 10C, 10Bk Paper feeding means 21 Paper feed cassette 20 Intermediate rollers 22A, 22B, 22C, 22D Resist roller 23 Fixing means 24 Paper discharge roller 25 Paper discharge tray 26 Endless belt-like intermediate transfer member 70 Rollers 71, 72, 73, 74 Support rails 82L, 82R Transfer material P

Claims

1. An electrostatic charge image developing toner containing toner base particles containing at least a binder resin, wherein a photosensitizer having a singlet oxygen generating ability is dispersed in a single molecular state in the binder resin, contained inside the toner base particles, or the photosensitizer having the singlet oxygen generating ability is supported in a single molecular state on metal oxide particles and contained in an external additive adhering to the toner base particles An electrostatic charge image developing toner characterized by the above.

2. In the measurement of the emission spectrum of the photosensitizer, when monochromatic light corresponding to the absorption maximum wavelength of the absorption spectrum of the solution of the photosensitizer is irradiated, phosphorescence having an emission maximum wavelength attributed to singlet oxygen is observed within the range of 1270 ± 20 nm The electrostatic charge image developing toner according to claim 1, characterized by the above.

3. The electrostatic charge image developing toner according to claim 1 or claim 2, characterized in that it exhibits coloring derived from the single molecular absorption spectrum of the photosensitizer as an indicator of the singlet oxygen generating ability.

4. The photosensitizer is a phthalocyanine dye or an analog thereof The electrostatic charge image developing toner according to any one of claims 1 to 3, characterized by the above.

5. The photosensitizer has a structure represented by the following general formula (1) The electrostatic charge image developing toner according to any one of claims 1 to 4, characterized by the above. 【Chemical 1】 (In the above general formula (1), M represents a Group 14 metal atom. Q １ and Q ２ each independently represent a monovalent axial ligand. Note that in the above general formula (1), either Q １ or Q ２ may not be present. A １ to A ４ each independently represent an atomic group that forms an aromatic ring which may have a substituent.)

6. The metal oxide particles contain a compound itself having a structure represented by the following general formula (2) or a reaction product formed by reacting and bonding with an atom or functional group contained in the metal oxide particles The electrostatic charge image developing toner according to any one of claims 1 to 5, characterized by the above. General formula (2): PS-(OH) ｎ (In the formula, PS represents a photosensitizer having a singlet oxygen generating ability. n represents an integer.)

7. PS in the general formula (2) represents a phthalocyanine dye or an analog thereof The electrostatic charge image developing toner according to claim 6, characterized by the above.

8. A method for manufacturing an electrostatic charge image developing toner for manufacturing the electrostatic charge image developing toner according to any one of claims 1 to 7, comprising a step of dispersing the photosensitizer in a single molecular state A method for manufacturing an electrostatic charge image developing toner, characterized by the above.

9. An image forming method using the electrostatic charge image developing toner according to any one of claims 1 to 7, comprising forming dots in a non-image area independently of the image area An image forming method characterized by the following.

10. The diameter of the dot is 60 μm or less. The image forming method according to claim 9, characterized by the above.

11. An image forming system having a charging means for a photoreceptor, a latent image forming means, a developing means, a transfer means, and a cleaning means, using the toner for electrostatic charge image development according to any one of claims 1 to 7. An image forming system characterized by the above.

12. An output formed using the toner for electrostatic charge image development, An output characterized by being formed using the toner for electrostatic charge image development according to any one of claims 1 to 7.

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