Image forming method and image forming apparatus

Abstract

To provide an image forming method with which an image having antibacterial properties and antiviral properties can be stably formed with the use of a toner that can be stably manufactured and has satisfactory electrostatic properties.SOLUTION: An image forming method has an electrostatic latent image forming step, a developing step, a transfer step, and a fixing step. A toner includes particles composed of a binder resin, a mold release agent, and an inorganic antibacterial / antiviral agent and satisfies all of the following conditions (1)-(3). When the number average particle diameter of the particles composed of the inorganic antibacterial / antiviral agent is X[μm] and the thickness of a layer of the toner fixed to a recording medium is Z[μm], 2.0X≤Z≤2.5X[μm] is satisfied. [Conditions] (1) The number average particle diameter X of the particles composed of the inorganic antibacterial / antiviral agent is 1.5≤X≤2.5[μm]. (2) When the weight average particle diameter of the toner is Y, 3X≤Y≤4X[μm]. (3) The content of the inorganic antibacterial / antiviral agent in the toner is 2.8 mass% or more and 5.0 mass% or less.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to an image forming method, toner, developer, printed matter, toner container unit, and image forming apparatus.

Background Art

[0002] In image formation by electrophotography, electrostatic recording, or electrostatic printing, a latent image due to electrostatic charges is formed on a photoreceptor such as a photoconductive substance. Then, charged toner is attached to this electrostatic latent image to form a visible image. After that, it is transferred to a recording medium such as paper and fixed to obtain an output image. Unlike a printing press, the electrophotographic method does not require a plate or the like, so it is suitable for small quantity and multi-variety copying and is an on-demand method compared to printing.

[0003] On the other hand, in addition to conventional monochrome toner and color toner, toners having various functions have been put into practical use. One of such functions is antibacterial toner. For example, in Patent Documents 1 to 4, various antibacterial toners have been proposed. By forming an image using antibacterial toner, the advantage that the formed image has antibacterial properties can be obtained. Thereby, for example, when an unspecified number of people touch a printed matter, it is expected that the possibility of bacteria and viruses transferring to others via the printed matter can be reduced.

[0004] The types, blending amounts, etc. of these toner components are carefully optimized, and a good balance of performance required for toner such as developing properties such as chargeability, electrical resistivity, magnetic properties, and fluidity, fixing properties such as fixability and colorability, storage stability, and handleability is required.

Summary of the Invention

Problems to be Solved by the Invention

[0005] However, toner is particles having a charging function, and is produced using a binder resin, a colorant, a charge control agent, a release agent, a surface treatment agent, a magnetic agent, etc. In the prior art, there were cases where toner could not be stably manufactured when a material having antibacterial or antiviral properties was contained. Also, there were cases where good chargeability could not be obtained when a material having antibacterial or antiviral properties was contained. Further, compared with conventional printing methods using ink, the image thickness tends to be thick, and it is desired to stably form an image having antibacterial or antiviral properties.

[0006] An object of the present invention is to provide an image forming method that can stably manufacture a toner having good chargeability and can stably form an image having antibacterial or antiviral properties.

Means for Solving the Problems

[0007] In order to solve the above problems, an image forming method of the present invention includes an electrostatic latent image forming step of forming an electrostatic latent image on an electrostatic latent image carrier, a developing step of developing the electrostatic latent image using toner to form a visible image, a transfer step of transferring the visible image onto a recording medium, and a fixing step of fixing the transferred image on the recording medium. The toner includes Toner base particles and external additives and satisfies all of the following conditions (1) to (3): The toner base particles include particles composed of a binder resin, a release agent, and an inorganic antibacterial and antiviral agent, When the number average particle diameter of the particles composed of the inorganic antibacterial and antiviral agent is X [μm] and the thickness of the layer of the toner fixed on the recording medium is Z [μm], it satisfies 2.0X ≤ Z ≤ 2.5X [μm]. [Conditions] (1) The number average particle diameter X of the particles composed of the inorganic antibacterial and antiviral agent is 1.5 ≤ X ≤ 2.5 [μm] (2) When the weight average particle diameter of the toner is Y, 3X ≤ Y ≤ 4X [μm] (3) The content of the inorganic antibacterial and antiviral agent in the toner is 2.8 mass% or more and 5.0 mass% or less.

Effects of the Invention

[0008] According to the present invention, it is possible to provide an image forming method that can stably produce an image having antibacterial and antiviral properties by using a toner that can be stably manufactured and has good chargeability.

Brief Description of the Drawings

[0009]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Figure 9

Figure 10

Figure 11

Figure 12

Figure 13

Embodiments for Carrying Out the Invention

[0010] Hereinafter, the toner, developer, printed matter, toner container unit, image forming apparatus, and image forming method according to the present invention will be described with reference to the drawings. Note that the present invention is not limited to the embodiments shown below, and can be modified within the scope that those skilled in the art can conceive, such as other embodiments, additions, modifications, deletions, etc., and as long as the functions and effects of the present invention are exhibited in any aspect, it is included in the scope of the present invention.

[0011] (Toner) The toner of the present invention contains a binder resin, a release agent, and particles composed of an inorganic antibacterial and antiviral agent, and is characterized by satisfying all of the following conditions (1) to (3). (1) When the number average particle diameter of the particles composed of the inorganic antibacterial and antiviral agent is X, 1.5 ≦ X ≦ 2.5 [μm] (2) When the weight average particle diameter of the toner is Y, 3X ≦ Y ≦ 4X [μm] (3) The content of the inorganic antibacterial and antiviral agent in the toner is 2.8 mass% or more and 5.0 mass% or less.

[0012] According to the present invention, it is possible to provide a toner that can be stably manufactured, has good chargeability, and can stably form an image having antibacterial and antiviral properties. According to the present invention, using an electrophotographic method, an image having stable and sufficient antibacterial and antiviral properties can be produced on demand.

[0013] The toner of the present invention has antibacterial and antiviral properties. It may have both antibacterial and antiviral properties, or may have either one of them. Further, the toner of the present invention may be referred to as an antibacterial and antiviral toner or the like.

[0014] The use of the toner of the present invention is not particularly limited and can be appropriately selected. For example, an image, such as a color image, may be formed using the toner of the present invention, or the toner of the present invention may be used on an image formed by other toners or the like. It is preferable to form a layer on the surface of the image with the toner of the present invention. In this case, it becomes easier to ensure antibacterial and antiviral properties. For example, it is preferable to form a layer with the toner of the present invention on a layer formed by other color toners. In this case, it is preferable to increase the transmittance of the layer formed by the toner of the present invention, and the layer formed by the color toner becomes clearer.

[0015] <Inorganic antibacterial and antiviral agent> The toner of the present invention contains particles composed of an inorganic antibacterial and antiviral agent. In the present invention, antibacterial and antiviral agents include antibacterial agents having antibacterial properties, antiviral agents having antiviral properties, components having antibacterial and antiviral properties, and the like. Inorganic antibacterial and antiviral agents include antibacterial agents and antiviral agents containing inorganic components.

[0016] In the following, there are places where an antibacterial agent is taken as an example for explanation, but unless otherwise specified, it also applies to antiviral agents and the like. In addition, the inorganic antibacterial and antiviral agent may be simply referred to as an antibacterial and antiviral agent.

[0017] The inorganic antibacterial and antiviral agent has, for example, one or more of the following properties (a) to (e), or preferably has them, and the inorganic antibacterial and antiviral agent is preferably used as an antibacterial agent for a developer. (a) It has excellent heat resistance and is stable even at 500 to 600 °C, and does not substantially thermally decompose at the temperature range of toner production and use. (i) It has high safety, and the oral mouse acute toxicity LD50 is very low at 2,000 mg / kg or more, and it is negative or extremely weak with respect to mutagenicity and skin irritation, and has low toxicity. (u) The antibacterial effect is semi-permanent. (e) It has a wide antibacterial spectrum. (o) It has excellent performance such as being difficult for microorganisms to acquire resistance.

[0018] As the inorganic antibacterial and antiviral agent, there is no particular limitation as long as it is an inorganic substance having antibacterial action and antiviral action, and it can be appropriately selected. For example, inorganic antibacterial agents and antiviral agents having antibacterial action and antiviral action can be mentioned.

[0019] As the antibacterial agent, an antibacterial agent containing a metal having antibacterial property is preferable. Examples of the metal having antibacterial property include silver, copper, zinc, platinum, nickel, titanium oxide having photocatalytic action, etc. Among these, preferably used antibacterial metals are silver, zinc, and titanium oxide having strong antibacterial power. These can be used alone, or two or more kinds of metals can be mixed and used. Also, these metal ions can be mentioned.

[0020] The inorganic antibacterial and antiviral agent preferably contains a carrier composed of alumina, zeolite, silicon-based glass or bentonite. For example, it is preferable to carry the metal ions of the above metals on the carrier. As such an antibacterial agent containing a carrier, from the viewpoint of the performance of the obtained developer, phosphate-based, silicate-based, soluble glass-based, etc. are used.

[0021] Examples of the phosphate-based include zirconium phosphate ZrO(HPO 4 ) 2 -based substances in which silver or zinc is bonded by ion exchange ability using it as a matrix. In addition, for example, calcium phosphate-based Ca 3 (PO 4 ) 2 , and calcium phosphate-based substances in which silver is adsorbed and bonded using hydroxyapatite Ca 10 (PO 4 ) 6 (OH) 2 as a matrix can be mentioned.

[0022] Examples of the silicate-based include zeolite Na 2 O·Al 2 O 3 ·2SiO2 ·4.5H 2 Utilizing the ion exchange ability of the O-supporting property, silver, copper, zinc, etc. are safely supported in the innumerable pores of zeolite particles in an ionic state, and at the same time, a sustained-release property is given, and a zeolite-based material that gradually releases silver ions, etc. and has the durability to maintain antibacterial properties for a long time can be mentioned. In addition to this, for example, silica gel SiO 2 ·nH 2 O (for example, a 1 g sample with a porous microstructure has a surface area of 450 m 2 or more) adsorbed or incorporated with a thiosulfite silver complex, etc., and a silica gel-based material can be mentioned.

[0023] As the soluble glass system, for example, in silicate glass Na 2 O·SiO 2 ·B 2 O 3 with a high solubility by increasing the B 2 O 3 component, silver, etc. are supported on the glass carrier, and the slow release of silver is controlled as the glass dissolves, and the like can be mentioned.

[0024] Thus, although the inorganic antibacterial and antiviral agent exhibits stable and excellent antibacterial and antiviral properties, it is known to affect the charging characteristics of the toner. Therefore, in the present invention, conditions (1) etc. are defined.

[0025] In the present invention, when the number average particle diameter of the particles composed of the inorganic antibacterial and antiviral agent is X, 1.5 ≦ X ≦ 2.5 [μm]. When the number average particle diameter X is less than 1.5 μm, the number of antibacterial and antiviral agents in the toner increases too much, and it is likely to affect the chargeability of the toner. As the lower limit value, it is preferably 1.8 μm or more. If the number average particle diameter X is larger than 2.5 μm, it becomes difficult to sufficiently contain it in the toner. For this reason, the antibacterial and antiviral agent does not reach each toner particle, and the concentration of the antibacterial and antiviral agent is likely to vary each time printing is repeated, making it impossible to obtain a stable antibacterial and antiviral effect. In addition, members in an electrophotographic system such as an electrostatic latent image carrier, an intermediate transfer belt, and a fixing belt may be easily damaged.

[0026] In the present invention, (2) when the weight average particle diameter of the toner is Y, 3X ≤ Y ≤ 4X [μm]. If the weight average particle diameter Y of the toner is smaller than 3 times (3X) the number average particle diameter X of the inorganic antibacterial and antiviral agent, the strength of the toner decreases, the toner is crushed in the developing machine to generate fine powder, and development is hindered. Therefore, when manufacturing toner by a pulverization method, the yield during pulverization significantly decreases. If Y is smaller than 3X, it becomes difficult to obtain a good toner manufacturing yield. If the weight average particle diameter Y of the toner is larger than 4 times (4X) the number average particle diameter X of the inorganic antibacterial and antiviral agent, the exposure to the toner surface and the fixing image surface is not sufficient, and it becomes difficult to obtain antibacterial and antiviral properties.

[0027] In the present invention, (3) the content of the inorganic antibacterial and antiviral agent in the toner is 2.8 mass% or more and 5.0 mass% or less. If the content of the inorganic antibacterial and antiviral agent in the toner is less than 2.8 mass%, sufficient antiviral properties may not be obtained. In addition, in the image formed using the toner, the surface exposure state of the antibacterial and antiviral agent is poor, and stable and good antibacterial and antiviral properties cannot be obtained. As the lower limit value, 3.5 mass% or more is preferable. If the content exceeds 5.0 mass%, it is likely to affect the electrical properties of the toner. The influence appears in the toner volume resistance value, dielectric constant, dielectric loss, etc., and deterioration of transferability may occur. As the upper limit value, it is preferably less than 4.5 mass%.

[0028] The number average particle diameter X of the inorganic antibacterial and antiviral agent in the present invention is measured by the following means. A printed matter with a layer containing an inorganic antibacterial and antiviral agent is cut vertically into flakes with a thickness of 100 μm or less using a razor blade. After embedding the cut pieces in an epoxy resin, they are ultrathin-sectioned to about 100 nm using an ultramicrotome ULTRACUT-S (manufactured by Leica Microsystems). The cross-sectional surface of the ultrathin section of the printed matter is digitally photographed at a magnification of 10,000 times to obtain a cross-sectional image of the layer containing the inorganic antibacterial and antiviral agent using a transmission electron microscope H7000 (manufactured by Hitachi, Ltd.). The cross-sectional image is binarized for the inorganic antibacterial and antiviral agent and other components using image analysis software (for example, A Image-kun (manufactured by Asahi Kasei Engineering Co., Ltd.)), and the individual areas are calculated and analyzed. Thereby, the average particle diameter (number average particle diameter X) of the inorganic antibacterial and antiviral agent in the layer containing the inorganic antibacterial and antiviral agent can be obtained.

[0029] Regarding the aggregates of the inorganic antibacterial and antiviral agent contained in the layer, the primary particle size is not taken as one particle unit, but the particle size is calculated with one lump of aggregate as one particle.

[0030] As a method for measuring the average diameter of the inorganic antiviral agent in the toner, for example, after embedding the toner in an epoxy resin and ultrathin-sectioning it to about 100 nm using an ultramicrotome ULTRACUT-S (manufactured by Leica Microsystems), the measurement is carried out in the same manner as the measurement of the average particle diameter (number average particle diameter X) of the inorganic antibacterial and antiviral agent in the above-mentioned layer containing the inorganic antibacterial and antiviral agent.

[0031] The shape of the particles made of the inorganic antibacterial and antiviral agent is not limited, but it is preferably a cube or a rectangular parallelepiped. In this case, the advantage that the antibacterial and antiviral agent is stably exposed on the image surface can be obtained. The shape of the particles made of the inorganic antibacterial and antiviral agent is observed by, for example, SEM (scanning electron microscope). It is preferable that 40% or more of the observed particles are cubes or rectangular parallelepipeds.

[0032] Note that the SEM images of the antibacterial agent used in the examples are shown in FIG. 11 described later. In the figure, (a) and (b) are images obtained at the same scale and observe different locations respectively. (c) and (d) are images obtained at the same scale and observe different locations respectively. In the illustrated example, the shape of the particles composed of the inorganic antibacterial and antiviral agent is cubic.

[0033] <Binder resin> The binder resin is not particularly limited, and all conventionally known resins can be used. Examples of the binder resin include styrene-based resins such as styrene, α-methylstyrene, chlorostyrene, styrene-propylene copolymer, styrene-butadiene copolymer, styrene-vinyl chloride copolymer, styrene-vinyl acetate copolymer, styrene-maleic acid copolymer, styrene-acrylic ester copolymer, styrene-methacrylic ester copolymer, styrene-acrylonitrile-acrylic ester copolymer, polyester resins, vinyl chloride resins, rosin-modified maleic acid resins, phenol resins, epoxy resins, polyethylene resins, polypropylene resins, ionomer resins, polyurethane resins, silicone resins, ketone resins, xylene resins, petroleum-based resins, hydrogenated petroleum-based resins, etc. These may be used alone or in combination of two or more. Among these, styrene-based resins containing aromatic compounds as constituent units and polyester resins are preferable, and polyester resins are more preferable.

[0034] The polyester resin is obtained by a polycondensation reaction of generally known alcohol and acid. Examples of the alcohol include diols such as polyethylene glycol, diethylene glycol, triethylene glycol, 1,2-propylene glycol, 1,3-propylene glycol, 1,4-propylene glycol, neopentyl glycol, 1,4-butanediol; etherified bisphenols such as 1,4-bis(hydroxymethyl)cyclohexane, bisphenol A, hydrogenated bisphenol A, polyoxyethylenated bisphenol A, polyoxypropylenated bisphenol A; divalent alcohol units substituted with saturated or unsaturated hydrocarbon groups having 3 to 22 carbon atoms; other divalent alcohol units; sorbitol, 1,2,3,6-hexanetetrol, 1,4-sorbitan, pentaerythritol dipentaerythritol, tripentaerythritol, sucrose, 1,2,4-butanetriol, 1,2,5-pentanetriol, glycerol, 2-methylpropanetriol, 2-methyl-1,2,4-butanetriol, trimethylolethane, trimethylolpropane, 1,3,5-trihydroxymethylbenzene and other polyhydric alcohol monomers having trivalency or higher. These may be used alone or in combination of two or more.

[0035] The acid is not particularly limited and can be appropriately selected according to the purpose, but carboxylic acid is preferred. Examples of the carboxylic acid include monocarboxylic acids such as palmitic acid, stearic acid, and oleic acid; dicarboxylic acid monomers such as maleic acid, fumaric acid, mesaconic acid, citraconic acid, terephthalic acid, cyclohexanedicarboxylic acid, succinic acid, adipic acid, sebacic acid, and malonic acid, and divalent organic acid monomers in which these are substituted with a saturated or unsaturated hydrocarbon group having 3 to 22 carbon atoms, anhydrides of these acids, dimers of lower alkyl esters and linoleic acid, 1,2,4-benzenetricarboxylic acid, 1,2,5-benzenetricarboxylic acid, 2,5,7-naphthalenetricarboxylic acid, 1,2,4-naphthalenetricarboxylic acid, 1,2,4-butanetricarboxylic acid, 1,2,5-hexanetricarboxylic acid, 1,3-dicarboxyl-2-methyl-2-methylenecarboxypropane, tetra(methylenecarboxyl)methane, 1,2,7,8-octanetetracarboxylic acid enbol trimer acid, and polyvalent carboxylic acid monomers having trivalency or more such as anhydrides of these acids. These may be used alone or in combination of two or more.

[0036] The binder resin may also contain a crystalline resin. The crystalline resin is not particularly limited as long as it has crystallinity and can be appropriately selected according to the purpose. Examples thereof include polyester resins, polyurethane resins, polyurea resins, polyamide resins, polyether resins, vinyl resins, and modified crystalline resins. These may be used alone or in combination of two or more. Among these, polyester resins, polyurethane resins, polyurea resins, polyamide resins, and polyether resins are preferable, and resins having at least one of a urethane skeleton and a urea skeleton are preferable in order to impart moisture resistance and immiscibility with the amorphous resin described below.

[0037] The weight average molecular weight (Mw) of the crystalline resin is preferably from 2,000 to 100,000, more preferably from 5,000 to 60,000, and particularly preferably from 8,000 to 30,000 from the viewpoint of fixing property. When the weight average molecular weight is 2,000 or more, the problem of deterioration of hot offset resistance can be prevented, and when it is 100,000 or less, the problem of deterioration of low temperature fixing property can be prevented.

[0038] <Release agent> As the release agent, either natural wax or synthetic wax can be used. These may be used alone or in combination of two or more. Examples of the natural wax include plant waxes such as carnauba wax, cotton wax, wood wax, rice wax; animal waxes such as beeswax, lanolin; mineral waxes such as ozokerite, ceresin; petroleum waxes such as paraffin, microcrystalline, petrolatum and the like.

[0039] Examples of the synthetic wax include synthetic hydrocarbon waxes such as Fischer-Tropsch wax, polyethylene wax; synthetic waxes such as esters, ketones, ethers; fatty acid amides such as 1,2-hydroxystearic acid amide, stearic acid amide, phthalimide anhydride, chlorinated hydrocarbon; crystalline polymers having a long-chain alkyl group in the side chain such as homopolymers or copolymers of polyacrylates such as poly(n-stearyl methacrylate), poly(n-lauryl methacrylate) (for example, n-stearyl acrylate-ethyl methacrylate copolymer, etc.).

[0040] Among these, it is preferable that the release agent contains monoester wax. Since the monoester wax has low compatibility with a general binder resin, it easily oozes out to the surface during fixing, exhibits high release property, and can ensure high gloss and high low temperature fixing property.

[0041] The monoester wax is preferably a synthetic ester wax. Examples of the synthetic ester wax include, for example, a monoester wax synthesized from a long-chain straight-chain saturated fatty acid and a long-chain straight-chain saturated alcohol. The long-chain straight-chain saturated fatty acid is represented by the general formula C n H 2n+1 COOH, and those with n of about 5 to 28 are preferably used. Further, the long-chain straight-chain saturated alcohol is represented by C n H 2n+1 OH, and n of about 5 to 28 is preferred.

[0042] Specific examples of the long-chain straight-chain saturated fatty acid include, for example, capric acid, undecylic acid, lauric acid, tridecylic acid, myristic acid, pentadecylic acid, palmitic acid, heptadecanoic acid, tetradecanoic acid, stearic acid, nonadecanoic acid, arachic acid, behenic acid, lignoceric acid, cerotic acid, heptacosanoic acid, montanic acid, and melissic acid. On the other hand, specific examples of the long-chain straight-chain saturated alcohol include, for example, amyl alcohol, hexyl alcohol, heptyl alcohol, octyl alcohol, capryl alcohol, nonyl alcohol, decyl alcohol, undecyl alcohol, lauryl alcohol, tridecyl alcohol, myristyl alcohol, pentadecyl alcohol, cetyl alcohol, heptadecyl alcohol, stearyl alcohol, nonadecyl alcohol, eicosyl alcohol, cerol alcohol, and heptadecanol, and may have substituents such as a lower alkyl group, an amino group, and a halogen.

[0043] The melting point of the release agent is preferably 50°C to 120°C. When the melting point of the release agent is within the above numerical range, it can effectively act as a release agent between the fixing roller and the toner interface, so that the high-temperature offset resistance can be improved without applying a release agent such as oil to the fixing roller. Specifically, when the melting point is 50°C or higher, it is possible to prevent the problem of deterioration of the heat storage stability of the toner. When the melting point is 120°C or lower, the release property at low temperature is not exhibited, and it is possible to prevent problems such as deterioration of the cold offset resistance and winding of paper around the fixing machine.

[0044] As for the measurement of the melting point of the release agent, for example, it can be determined by measuring the maximum endothermic peak using a TG-DSC system TAS-100 (manufactured by Rigaku Corporation), which is a differential scanning calorimeter.

[0045] As for the content of the release agent, 1% by mass to 20% by mass is preferable with respect to the binder resin, and 3% by mass to 10% by mass is more preferable. When the content is 1% by mass or more, it is possible to prevent the problem that the offset prevention effect becomes insufficient, and when it is 20% by mass or less, it is possible to prevent the problems that the transferability and durability decrease.

[0046] Also, as for the content of the monoester wax, 4 parts by mass to 8 parts by mass is preferable with respect to 100 parts by mass of the toner, and 5 parts by mass to 7 parts by mass is more preferable. When the content is 4 parts by mass or more, it is possible to prevent the problems that the bleeding to the surface during fixing becomes insufficient, the releasability deteriorates, and the gloss, low-temperature fixability, and high-temperature offset resistance decrease. When the content is 8 parts by mass or less, it is possible to prevent the problems that the amount of the release agent deposited on the toner surface increases, the storage stability of the toner decreases, and the filming property on the photoreceptor or the like decreases.

[0047] The toner of the present invention preferably contains a wax dispersant, and the dispersant is preferably a copolymer composition containing at least styrene, butyl acrylate, and acrylonitrile as monomers, and a polyethylene adduct of the copolymer composition.

[0048] The content of the wax dispersant is preferably 7 parts by mass or less with respect to 100 parts by mass of the toner. By containing the wax dispersant, a wax dispersion effect can be obtained, and an improvement in storage stability can be expected stably without being affected by the manufacturing method. Further, due to the wax dispersion effect, the wax diameter becomes smaller, and the filming phenomenon on a photoreceptor or the like can be suppressed. When the content is 7 parts by mass or less, the amount of incompatible components with respect to the polyester resin increases, resulting in a decrease in gloss, and the wax dispersibility becomes too high, so that the filming resistance is improved, but the bleeding of the wax to the surface during fixing deteriorates, and problems such as a decrease in low-temperature fixability and hot offset resistance can be prevented.

[0049] <Other components> As the other components, there are usually no particular restrictions as long as they are contained in the toner, and they can be appropriately selected according to the purpose. Examples include charge control agents and external additives.

[0050] <<Charge control agent>> As the charge control agent, all known ones can be used. Examples include nigrosine dyes, triphenylmethane dyes, chromium-containing metal complex dyes, molybdic acid chelate pigments, rhodamine dyes, alkoxyamines, quaternary ammonium salts (including fluorine-modified quaternary ammonium salts), alkylamides, simple substances or compounds of phosphorus, fluorine-based activators, metal salts of salicylic acid, and metal salts of salicylic acid derivatives. These may be used alone or in combination of two or more.

[0051] As the charge control agent, those synthesized as appropriate may be used, or commercially available products may be used. Examples of the commercially available products include Bontron 03, Bontron P-51, Bontron S-34, E-82, E-84, E-89 (manufactured by Orient Chemical Industries Co., Ltd.), TP-302, TP-415, Copy Charge PSY VP2038, Copy Blue PR, Copy Charge NEG VP2036, Copy Charge NX VP434 (manufactured by Hoechst), LRA-901, LR-147 (manufactured by Nippon Carlit Co., Ltd.), and the like.

[0052] The content of the charge control agent can be appropriately selected according to the type of the binder resin, the presence or absence of additives used as necessary, and the toner manufacturing method including the dispersion method. However, with respect to 100 parts by mass of the binder resin, 0.1 part by mass to 5 parts by mass is preferable, and 0.2 part by mass to 2 parts by mass is more preferable. When the content is 5 parts by mass or less, the chargeability of the toner is too large, the effect of the main charge control agent is reduced, the electrostatic attraction to the developing roller increases, and problems such as a decrease in the fluidity of the developer and a decrease in the image density can be prevented.

[0053] Also, among charge control agents, it is also possible to control the thermal properties of the toner by using metal salts of trivalent or higher valences. By including the metal salt, a crosslinking reaction proceeds with the acidic group of the binder resin during fixing, and a weak three-dimensional crosslinking is formed, so that high-temperature offset resistance can be obtained while maintaining low-temperature fixability.

[0054] Examples of the metal salt include metal salts of salicylic acid derivatives, acetylacetonate metal salts, and the like. The metal is not particularly limited as long as it is a polyvalent ionic metal of trivalent or higher, and can be appropriately selected according to the purpose. Examples include iron, zirconium, aluminum, titanium, nickel, and the like. Among these, metal compounds of salicylic acid of trivalent or higher are preferable.

[0055] The content of the metal salt is not particularly limited and can be appropriately selected according to the purpose. For example, with respect to 100 parts by mass of the toner, 0.5 to 2 parts by mass is preferable, and 0.5 to 1 part by mass is more preferable. When the content is 0.5 part by mass or more, it is possible to prevent the problem of inferior hot offset resistance. When the content is 2 parts by mass or less, it is possible to prevent the problem of inferior glossiness.

[0056] <<External additive>> The external additive is contained to assist fluidity, developability, and chargeability. The external additive is not particularly limited and can be appropriately selected according to the purpose. For example, inorganic fine particles, polymer-based fine particles, etc. can be mentioned.

[0057] Examples of the inorganic fine particles include silica, alumina, titanium oxide, barium titanate, magnesium titanate, calcium titanate, strontium titanate, zinc oxide, tin oxide, silica sand, clay, mica, wollastonite, diatomaceous earth, chromium oxide, cerium oxide, cinder, antimony trioxide, magnesium oxide, zirconium oxide, barium sulfate, barium carbonate, calcium carbonate, silicon carbide, silicon nitride, etc. These may be used alone or in combination of two or more.

[0058] Examples of the polymer-based fine particles include polystyrene obtained by soap-free emulsion polymerization, suspension polymerization, dispersion polymerization, methacrylic acid ester or acrylic acid ester copolymer, silicone, benzoguanamine, nylon and other polycondensation systems, polymer particles made of thermosetting resins, etc.

[0059] The external additive can be surface-treated with a surface treatment agent to increase hydrophobicity and prevent deterioration of fluidity and charge characteristics even under high humidity.

[0060] Examples of the surface treatment agent include silane coupling agents, silylating agents, silane coupling agents having a fluorinated alkyl group, organic titanate coupling agents, aluminum-based coupling agents, silicone oils, modified silicone oils, and the like.

[0061] The primary particle diameter of the external additive is preferably 5 nm to 2 μm, more preferably 5 nm to 500 nm. Further, the specific surface area of the external additive by the BET method is preferably 20 m 2 / g to 500 m 2 / g.

[0062] The content of the external additive is preferably 0.01% by mass to 5% by mass, more preferably 0.01% by mass to 2.0% by mass, based on the toner.

[0063] <<Cleaning property improver>> The cleaning property improver is contained to remove the developer remaining after transfer on the photoreceptor or the primary transfer medium. Examples of the cleaning property improver include fatty acid metal salts such as zinc stearate, calcium stearate, and stearic acid; polymer fine particles such as those produced by soap-free emulsion polymerization of polymethyl methacrylate fine particles and polystyrene fine particles. The polymer fine particles preferably have a relatively narrow particle size distribution and a volume average particle diameter of 0.01 to 1 μm.

[0064] <Toner set> The toner of the present invention may form an image alone or may form an image in combination with other toners, for example, a color toner. By forming an image using the toner of the present invention, an antibacterial and antiviral function can be imparted to the printed matter. As described above, it is preferable to form a layer of the toner of the present invention on a layer formed by another toner, for example, a color toner, which makes it easier to ensure antibacterial and antiviral properties.

[0065] Hereinafter, as an example of what can be used in combination with the toner of the present invention, a color toner will be described as an example. To distinguish it from the color toner, the toner of the present invention may be referred to as an antibacterial and antiviral toner or the like.

[0066] <<Color toner>> The color toner contains a binder resin and a colorant, and further contains other components as necessary. For the other components, the same components as the other components can be used.

[0067] The color toner is preferably selected from cyan toner, magenta toner, yellow toner, and black toner, and more preferably cyan toner, magenta toner, yellow toner, and black toner. In addition, white toner and the like can be mentioned.

[0068] -Binder resin- The binder resin contained in the color toner is not particularly limited and can be appropriately selected according to the purpose, but preferably contains a gel. The gel fraction is preferably 0.5% by mass or more and 10% by mass or less based on the binder resin. Even when the gel is not contained, the binder resin used in the color toner preferably contains a high molecular weight substance having a weight average molecular weight of 100,000 or more. By containing a gel or a high molecular weight substance having a weight average molecular weight of 100,000 or more, hot offset can be prevented.

[0069] It should be noted that the same binder resin as the above antibacterial and antiviral toner can be used for the color toner.

[0070] -Colorant- Examples of the colorant include naphthol yellow S, Hansa yellow (10G, 5G, G), cadmium yellow, yellow iron oxide, loess, lead yellow, titanium yellow, polyazo yellow, oil yellow, Hansa yellow (GR, A, RN, R), pigment yellow L, benzidine yellow (G, GR), permanent yellow (NCG), Balkan fast yellow (5G, R), tartrazine lake, quinoline yellow lake, anthrazane yellow BGL, isoindolinone yellow, red iron oxide, red lead, minium, cadmium red, cadmium mercury red, antimony red, permanent red 4R, para red, phthalein red, parachlororthonitroaniline red, resorcin fast scarlet G, brilliant fast scarlet, brilliant carmine BS, permanent red (F2R, F4R, FRL, FRLL, F4RH), fast scarlet VD, Balkan fast rubine B, brilliant scarlet G, resorcin rubine GX, permanent red F5R, brilliant carmine 6B, pigment scarlet 3B, Bordeaux 5B, toluidine maroon, permanent Bordeaux F2K, heliobordeaux BL, Bordeaux 10B, bon maroon light, bon maroon medium, eosin lake, rhodamine lake B, rhodamine lake Y, alizarin lake, thioindigo red B, thioindigo maroon, oil red, quinacridone red, pyrazolone red, polyazo red, chrome vermilion, benzidine orange, perinone orange, oil orange, cobalt blue, cerulean blue, alkali blue lake, peacock blue lake, victoria blue lake, metal-free phthalocyanine blue, phthalocyanine blue, fast sky blue, indanthrene blue (RS, BC), indigo, dioxane violet, anthraquinone violet, chrome green, zinc green, pyridine, emerald green, pigment green B, naphthol green B, green gold, acid green lake, malachite green lake, phthalocyanine green, anthraquinone green, titanium oxide, zinc white, lithopone, perylene black, perinone black, and mixtures thereof.These may be used alone or in combination of two or more.

[0071] When used as a process color toner, the following colorants are preferred for each of black, cyan, magenta, and yellow. For black, carbon black is preferred. For cyan, C.I. Pigment Blue 15:3 is preferred. For magenta, C.I. Pigment Red 122 and C.I. Pigment Red 269 are preferred. For yellow, C.I. Pigment Yellow 74, C.I. Pigment Yellow 155, C.I. Pigment Yellow 180, and C.I. Pigment Yellow 185 are preferred. These colorants may be used alone or in combination of two or more. The content of the colorant contained in the color toner can be appropriately selected.

[0072] <Toner particle size> As described above, it is necessary for the number average particle size X of the antibacterial and antiviral agent and the weight average particle size Y of the toner to satisfy the above condition (2). The weight average particle size Y of the toner (antibacterial and antiviral toner) of the present invention is preferably 5 μm to 9 μm, more preferably 6 μm to 8 μm. If it is smaller than 5 μm, defects are likely to occur in the image forming process such as development, transfer, and cleaning due to the influence of the adhesion force. If it is larger than 9 μm, when outputting a solid image that covers the entire surface of the substrate (also referred to as a recording medium, etc.), the adhesion amount required to completely cover the substrate increases.

[0073] The weight average particle size of the color toner is preferably 4 μm to 7 μm, more preferably 5 μm to 6 μm. When the weight average particle size of the color toner is within the above range, minute dots of 600 dpi or more can be reproduced, and a high-quality image can be obtained. This has the advantage that toner particles with a sufficiently small particle size can be obtained for minute latent image dots, and excellent dot reproducibility can be obtained.

[0074] In addition, when the weight average particle diameter (D4) of the color toner is 4 μm or more, phenomena such as a decrease in transfer efficiency and a decrease in blade cleaning performance can be prevented. When the weight average particle diameter (D4) of the color toner is 7 μm or less, it is possible to suppress problems such as the occurrence of image information disturbance due to the entry of the color toner overlaid on the image before fixing as described above, and the difficulty of suppressing the scattering of characters and lines.

[0075] In addition, as the ratio (D4 / D1) of the weight average particle diameter (D4) to the number average particle diameter (D1), 1.00 to 1.40 is preferable, and 1.05 to 1.30 is more preferable. The closer the ratio (D4 / D1) is to 1.00, the sharper the particle size distribution indicates.

[0076] In such toner with a small particle size and a narrow particle size distribution, the charge amount distribution of the toner becomes uniform, a high-quality image with less background fogging can be obtained, and in the electrostatic transfer method, the transfer rate can be increased.

[0077] In a full-color image forming method in which a multicolor image is formed by overlapping toner images of different colors, the amount of toner adhered to the paper is larger than that in a monochrome image forming method in which an image is formed with only one color of black toner and there is no need to overlap toner images of different colors. That is, since the amount of toner to be developed, transferred, and fixed increases, problems that deteriorate the image quality such as the above-mentioned decrease in transfer efficiency, decrease in blade cleaning performance, scattering of characters and lines, and background fogging are likely to occur, and the management of the weight average particle diameter (D4) and the ratio (D4 / D1) of the weight average particle diameter (D4) to the number average particle diameter (D1) becomes important.

[0078] The measurement of the particle size distribution of toner particles can be performed using a measuring device for the particle size distribution of toner particles by the Coulter counter method. Examples of the device include Coulter Counter TA-II and Coulter Multisizer II (both manufactured by Coulter).

[0079] A specific measurement method is as follows, for example. First, 0.1 mL to 5 mL of a surfactant (such as alkylbenzene sulfonate) as a dispersant is added to 100 mL to 150 mL of an electrolytic aqueous solution. The electrolytic aqueous solution is prepared by using primary sodium chloride to prepare an approximately 1% NaCl aqueous solution, and examples include ISOTON-II (manufactured by Coulter). Next, 2 mg to 20 mg of a measurement sample is added. The electrolytic solution in which the sample is suspended is subjected to a dispersion treatment with an ultrasonic disperser for about 1 minute to 3 minutes. Using a 100 μm aperture as an aperture by the said measuring device, the weight and number of toner particles or toner are measured, and the weight distribution and number distribution are calculated. From the obtained distribution, the weight average particle diameter (D4) and number average particle diameter (D1) of the toner can be determined.

[0080] As channels, 13 channels of less than 2.00 to 2.52 μm; less than 2.52 to 3.17 μm; less than 3.17 to 4.00 μm; less than 4.00 to 5.04 μm; less than 5.04 to 6.35 μm; less than 6.35 to 8.00 μm; less than 8.00 to 10.08 μm; less than 10.08 to 12.70 μm; less than 12.70 to 16.00 μm; less than 16.00 to 20.20 μm; less than 20.20 to 25.40 μm; less than 25.40 to 32.00 μm; less than 32.00 to 40.30 μm are used, and particles with a particle diameter of 2.00 μm or more and less than 40.30 μm are targeted.

[0081] <Method for manufacturing toner> As the method for manufacturing the toner of the present invention, conventionally known methods such as a melt-kneading and pulverization method and a polymerization method can be applied. Also, for the manufacturing methods of color toner and antibacterial and antiviral toner, the same manufacturing method may be used, or different manufacturing methods may be used. For example, the color toner may be manufactured by a polymerization method, and the antibacterial and antiviral toner may be manufactured by a melt-kneading and pulverization method.

[0082] <<Melt-kneading and pulverization method>> In the melt-kneading and pulverization method, in its manufacturing process, for example (1) A step of melt-kneading at least a binder resin and an antibacterial and antiviral agent or a colorant and a release agent (2) Step of pulverizing / classifying the melt-kneaded toner composition (3) Step of externally adding inorganic fine particles It has. It is preferable in terms of cost to side-knead the fine powder replicated in the pulverizing / classifying step of (2) as the raw material of (1).

[0083] As the kneader used for kneading, a closed kneader, a single-screw or twin-screw extruder, an open roll type kneader, etc. can be used. Examples of the types of kneaders include KRC kneader (manufactured by Kurimoto Iron Works Co., Ltd.), Buss co-kneader (manufactured by Buss), TEM type extruder (manufactured by Toshiba Machine Co., Ltd.), TEX twin-screw kneader (manufactured by Japan Steel Works, Ltd.), PCM kneader (manufactured by Ikegai Iron Works Co., Ltd.), three-roll mill, mixing roll mill, kneader (manufactured by Inoue Manufacturing Co., Ltd.), Needex (manufactured by Mitsui Mining Co., Ltd.), MS type pressure kneader, Nidaluder (manufactured by Moriyama Manufacturing Co., Ltd.), Banbury mixer (manufactured by Kobe Steel, Ltd.), etc.

[0084] Examples of the pulverizer include counter jet mill, micron jet, Inomizer (manufactured by Hosokawa Micron Corporation), IDS type mill, PJM jet pulverizer (manufactured by Nippon Pneumatic Mfg. Co., Ltd.), cross jet mill (manufactured by Kurimoto Iron Works Co., Ltd.), Ulmax (manufactured by Nippon Catalytic Chemical Industries Co., Ltd.), SK jet or mill (manufactured by Seishin Enterprise Co., Ltd.), Cryptron (manufactured by Kawasaki Heavy Industries, Ltd.), turbo mill (manufactured by Turbo E Co., Ltd.), super rotor (manufactured by Nisshin Engineering Co., Ltd.), etc.

[0085] Examples of the classifier include Classier, Micron Classifier, Spedic Classifier (manufactured by Seishin Enterprise Co., Ltd.), Turbo Classifier (manufactured by Nisshin Engineering Co., Ltd.), Micron Separator, Turbo Preplex (ATP), TSP Separator (manufactured by Hosokawa Micron Corporation), Elbow Jet (manufactured by Nippon Steel Mining Co., Ltd.), Dispersion Separator (manufactured by Nippon Pneumatic E Co., Ltd.), YM Microcut (manufactured by Yaskawa Shosha Co., Ltd.).

[0086] Examples of screening devices used for screening coarse particles include, for example, Ultrasonic (manufactured by Koyo Sangyo Co., Ltd.), Resonative, Gyro Shifter (manufactured by Tokuju Kousakusho Co., Ltd.), Vibra Sonic System (manufactured by Dalton Co., Ltd.), Soniclean (manufactured by Shin-Tokyo Industries Co., Ltd.), Turbo Screener (manufactured by Turbo E Co., Ltd.), Micro Shifter (manufactured by Makino Sangyo Co., Ltd.), circular vibrating screen, and the like.

[0087] [[Coincidence method]] As the coincidence method, a conventionally known method can be used. Examples of the coincidence method include the following procedure. First, the colorant, binder resin, and release agent are dispersed in an organic solvent to prepare a toner material liquid (oil phase). It is preferable to add a polyester prepolymer (A) having an isocyanate group to the toner material liquid and react it during granulation so that the urea-modified polyester resin is contained in the toner.

[0088] Next, the toner material liquid is emulsified in an aqueous medium in the presence of a surfactant and resin fine particles. As the aqueous medium, the aqueous solvent used for the aqueous medium may be water alone or may contain an organic solvent such as alcohol.

[0089] The amount of the aqueous solvent used relative to 100 parts by mass of the toner material liquid is usually preferably 50 parts by mass to 2,000 parts by mass, and more preferably 100 parts by mass to 1,000 parts by mass.

[0090] The resin fine particles are not particularly limited as long as they are resins capable of forming an aqueous dispersion, and can be appropriately selected according to the purpose. Examples thereof include vinyl resins, polyurethane resins, epoxy resins, polyester resins, and the like. After dispersion, the organic solvent is removed from the emulsified dispersion (reactant), and washed and dried to obtain toner base particles.

[0091] (Developer) The toner (antibacterial and antiviral toner) of the present invention may be used as a one-component developer or a two-component developer. The same applies to color toners and the like.

[0092] When the toner of the present invention is used in a two-component developer, it may be used by mixing with a magnetic carrier. The content ratio of the carrier and the toner in the developer is preferably 1 to 10 parts by mass of the toner with respect to 100 parts by mass of the carrier.

[0093] As the magnetic carrier, those conventionally known can be used. For example, iron powder, ferrite powder, magnetite powder, magnetic resin carrier, etc. having a particle diameter of about 20 μm to 200 μm can be mentioned.

[0094] The magnetic carrier may also be coated. Examples of the coating material for coating the magnetic carrier include amino resins such as urea-formaldehyde resin, melamine resin, benzoguanamine resin, urea resin, polyamide resin, and epoxy resin; polyvinylidene resins such as polyvinyl; polystyrene resins such as acrylic resin, polymethyl methacrylate resin, polyacrylonitrile resin, polyvinyl acetate resin, polyvinyl alcohol resin, polyvinyl butyral resin, polystyrene resin, and styrene-acrylic copolymer resin; halogenated olefin resins such as polyvinyl chloride; polyester resins such as polyethylene terephthalate resin and polybutylene terephthalate resin; polycarbonate resins, polyethylene resins, polyvinyl fluoride resin, polyvinylidene fluoride resin, polytetrafluoroethylene resin, polyhexafluoropropylene resin, copolymers of vinylidene fluoride and acrylic monomers, copolymers of vinylidene fluoride and vinyl fluoride, fluoroternary polymers such as tetrafluoroethylene, vinylidene fluoride, and non-fluorinated monomers, and silicone resins.

[0095] Furthermore, if necessary, conductive powder or the like may be contained in the coating resin. As the conductive powder, metal powder, carbon black, titanium oxide, tin oxide, zinc oxide, etc. can be used. These conductive powders preferably have an average particle diameter of 1 μm or less. When the average particle diameter is 1 μm or less, the problem of difficulty in controlling the electrical resistance can be prevented.

[0096] (Image Forming Method and Image Forming Apparatus) The image forming method of the present invention includes an electrostatic latent image forming step of forming an electrostatic latent image on an electrostatic latent image carrier, a developing step of developing the electrostatic latent image with toner to form a visible image, a transferring step of transferring the visible image onto a recording medium, and a fixing step of fixing the transferred image on the recording medium, wherein the toner is the toner of the present invention. Other steps are included as necessary.

[0097] The image forming apparatus of the present invention includes an electrostatic latent image carrier, an electrostatic latent image forming means for forming an electrostatic latent image on the electrostatic latent image carrier, a developing means for developing the electrostatic latent image with toner to form a visible image, a transferring means for transferring the visible image onto a recording medium, and a fixing means for fixing the transferred image on the recording medium, wherein the toner is the toner of the present invention. Other means are included as necessary.

[0098] The image forming method and image forming apparatus of the present invention may use toners other than the toner of the present invention (antibacterial and antiviral toner), for example, antibacterial and antiviral toner and color toner may be used. Note that the visible image formed by the antibacterial and antiviral toner may be referred to as an antibacterial and antiviral toner image, etc., and the visible image formed by the color toner may be referred to as a color toner image, etc.

[0099] In the image forming method and the image forming apparatus, it is preferable that the antibacterial and antiviral toner image is a solid image formed on the outermost surface of the entire recording medium regardless of the presence or absence of a color image. The surface where the antibacterial and antiviral toner layer is not formed has no antibacterial and antiviral property, and there is a possibility that bacteria and viruses may propagate on the surface where it is not formed.

[0100] Further, the image forming method and image forming apparatus of the present invention are characterized in that when the number average particle diameter of the particles composed of the inorganic antibacterial and antiviral agent is X [μm] and the thickness of the toner layer fixed on the recording medium is Z [μm], 2.0X ≦ Z ≦ 2.5X [μm] is satisfied.

[0101] If the thickness Z [μm] is less than 2.0X [μm], minute unattached portions are likely to occur in the solid image. If it is greater than 2.0X [μm], the antibacterial and antiviral agent is less likely to be exposed on the layer surface, so there may be variations in the antibacterial and antiviral functions. To make the thickness Z [μm] of the toner layer on the recording medium satisfy 2.0X ≤ Z ≤ 2.5X [μm], for example, image formation is performed by adjusting development conditions and the like to adjust the amount of the antibacterial and antiviral toner deposited on the image.

[0102] The region for forming the antibacterial and antiviral toner layer can be appropriately changed. However, it is preferable to form a layer of color toner on the recording medium and further form an antibacterial and antiviral toner layer over the entire surface of the recording medium thereon. By forming it over the entire surface of the recording medium, regions without antibacterial and antiviral functions can be eliminated, and the antibacterial and antiviral properties can be improved.

[0103] In the image forming method and the image forming apparatus of the present invention, the amount of the inorganic antibacterial and antiviral agent per unit area of the image is 2 μg / cm 2 or more and 22 μg / cm 2 or less, which is preferable. When it is within this range, a good transmittance can be obtained as the antibacterial and antiviral toner layer. If the amount of the inorganic antibacterial and antiviral agent per unit area of the image exceeds a certain amount, the transmittance of the antibacterial and antiviral toner layer may decrease.

[0104] <Electrostatic latent image carrier> As the electrostatic latent image carrier (hereinafter, may be referred to as "electrophotographic photoreceptor", "photoreceptor", "image carrier"), there are no particular restrictions on its material, shape, structure, size, etc., and it can be appropriately selected from known ones. Examples of the shape of the image carrier include a drum shape and a belt shape. Examples of the material of the image carrier include inorganic photoreceptors such as amorphous silicon and selenium, and organic photoreceptors (OPC) such as polysilane and phthalopolymethine.

[0105] <Electrostatic latent image forming step and electrostatic latent image forming means> The electrostatic latent image forming step is a step of forming an electrostatic latent image on the electrostatic latent image carrier. The formation of the electrostatic latent image can be performed, for example, by uniformly charging the surface of the electrostatic latent image carrier and then exposing it imagewise, and can be performed by an electrostatic latent image forming means. The electrostatic latent image forming means includes, for example, at least a charging means (charger) for uniformly charging the surface of the electrostatic latent image carrier and an exposure means (exposure device) for exposing the surface of the electrostatic latent image carrier imagewise.

[0106] The charging can be performed, for example, by applying a voltage to the surface of the electrostatic latent image carrier using the charger.

[0107] The charger is not particularly limited and can be appropriately selected according to the purpose. For example, known contact chargers provided with conductive or semiconductive rolls, brushes, films, rubber blades, etc., non-contact chargers using corona discharge such as corotrons and scorotrons, etc. can be mentioned.

[0108] The charger is preferably arranged in contact with or in a non-contact state with the electrostatic latent image carrier and charges the surface of the electrostatic latent image carrier by superimposing a DC voltage and an AC voltage. Further, it is preferable that the charger is a charging roller arranged in a non-contact and close state with the electrostatic latent image carrier via a gap tape, and charges the surface of the electrostatic latent image carrier by superimposing a DC voltage and an AC voltage on the charging roller.

[0109] The exposure can be performed, for example, by exposing the surface of the electrostatic latent image carrier imagewise using the exposure device. The exposure device is not particularly limited as long as it can expose the surface of the electrostatic latent image carrier charged by the charger imagewise as the image to be formed, and can be appropriately selected according to the purpose. For example, various exposure devices such as a copying optical system, a rod lens array system, a laser optical system, a liquid crystal shutter optical system, etc. can be mentioned. In the present invention, a light backside exposure method in which exposure is performed in an image-like manner from the backside of the electrostatic latent image carrier may be employed.

[0110] <Developing Step and Developing Means> The developing step is a step of developing an electrostatic latent image using toner to form a visible image (toner image). The developing means is means for developing an electrostatic latent image using toner to form a visible image (toner image).

[0111] As described above, the developing means and the developing step may form a toner image using, for example, antibacterial and antiviral toner and color toner. Further, as the color toner, for example, a plurality of color toners having different colorants may be used, and a set of a plurality of color toners is also referred to as a color toner set. The formation of the toner image can be performed, for example, by developing the electrostatic latent image using the antibacterial and antiviral toner and the color toner set, and can be performed by the developing means.

[0112] The developing means (hereinafter, also referred to as "developing and adhering means") preferably includes, for example, a developer that stores each toner of the antibacterial and antiviral toner and the color toner set and can apply each toner to the electrostatic latent image in a contact or non-contact manner, and a developer provided with a toner-containing container is more preferable.

[0113] The developer may be a single-color developer or a multi-color developer. For example, those having a stirrer that stirs and charges each toner and a rotatable magnetic roller are preferably exemplified.

[0114] In the developing device, for example, the toner and the carrier are mixed and stirred, and the toner is charged by the friction during this process. The charged toner is held in a standing state on the surface of the rotating magnetic roller, and a magnetic brush is formed. Since the magnetic roller is disposed near the electrostatic latent image carrier (photoconductor), a part of the toner that constitutes the magnetic brush formed on the surface of the magnetic roller moves to the surface of the electrostatic latent image carrier (photoconductor) by an electric attractive force. As a result, the electrostatic latent image is developed with the toner, and a toner image made of the toner is formed on the surface of the electrostatic latent image carrier (photoconductor).

[0115] The toner image includes, for example, an antibacterial and antiviral toner image formed by the antibacterial and antiviral toner and a color toner image formed by the color toner.

[0116] Examples of the colors that constitute the color toner include a four-color set of black (Bk), cyan (C), magenta (M), and yellow (Y), a three-color set of cyan (C), magenta (M), and yellow (Y), and black (Bk) single color. Among these, a four-color set is preferable in that it is a color toner set that can be mounted on a general electrophotographic four-color image forming apparatus.

[0117] <Fixing step and fixing means> The fixing step is a step of fixing the transfer image transferred to the recording medium, and it may be performed each time the transfer is made to the recording medium for each color developer, or it may be performed simultaneously at once in a stacked state for each color developer.

[0118] The fixing means is not particularly limited as long as it is a means for fixing the transfer image transferred to the recording medium, and it can be appropriately selected according to the purpose. However, a known heating and pressing means is preferable. Examples of the heating and pressing means include a combination of a heating roller and a pressing roller, a combination of a heating roller, a pressing roller, and an endless belt, and the like.

[0119] The fixing means preferably includes a heating member having a heating element, a film in contact with the heating member, and a pressing member that presses against the heating member through the film, and is a means for heating and fixing by passing a recording medium on which an unfixed image is formed between the film and the pressing member. The heating in the heating and pressing means is usually preferably 80°C to 200°C. In the present invention, depending on the purpose, a known optical fuser may be used, for example, together with or instead of the fixing step and the fixing means.

[0120] <Other steps and other means> Examples of the other steps include a charge elimination step, a cleaning step, a recycling step, a control step, and the like.

[0121] The charge elimination step is a step of applying a charge elimination bias to the electrostatic latent image carrier to eliminate charge, and can be preferably performed by charge elimination means. The charge elimination means is not particularly limited as long as it can apply a charge elimination bias to the electrostatic latent image carrier, and can be appropriately selected from known charge eliminators. For example, a charge elimination lamp is preferably mentioned.

[0122] The cleaning step is a step of removing the toner remaining on the electrostatic latent image carrier, and can be preferably performed by cleaning means. The cleaning means is not particularly limited as long as it can remove the toner remaining on the electrostatic latent image carrier, and can be appropriately selected from known cleaners. For example, a magnetic brush cleaner, an electrostatic brush cleaner, a magnetic roller cleaner, a blade cleaner, a brush cleaner, a web cleaner, etc. are preferably mentioned.

[0123] The recycling step is a step of recycling the toner removed by the cleaning step to the developing means, and can be preferably performed by recycling means. The recycling means is not particularly limited, and examples include known conveying means.

[0124] The control step is a step of controlling each of the above steps, and each step can be preferably performed by a control means. The control means is not particularly limited as long as it can control the movement of each of the above means, and can be appropriately selected according to the purpose. Examples thereof include devices such as a sequencer and a computer.

[0125] Here, the image forming method and the image forming apparatus of the present invention will be described with reference to the drawings. FIG. 1 is a diagram showing the whole of an example of the image forming apparatus A. Image data sent to an image processing unit 14 (hereinafter referred to as "IPU") creates five types of each image signal of Y (yellow), M (magenta), C (cyan), Bk (black), and Abv (antibacterial and antiviral).

[0126] Next, each image signal of Y, M, C, Bk, and Abv in the image processing unit is transmitted to a writing unit 15. The writing unit 15 modulates and scans five laser beams for Y, M, C, Bk, and Abv, respectively, and after charging the photosensitive drum by charging units 51, 52, 53, 54, and 55, sequentially forms an electrostatic latent image on each of the photosensitive drums 21, 22, 23, 24, and 25. Here, for example, the first photosensitive drum 21 corresponds to Y, the second photosensitive drum 22 corresponds to M, the third photosensitive drum 23 corresponds to C, the fourth photosensitive drum 24 corresponds to Bk, and the fifth photosensitive drum 25 corresponds to Abv.

[0127] Next, toner images of respective colors are formed on the photosensitive drums 21, 22, 23, 24, and 25 by developing units 31, 32, 33, 34, and 35 as developing and attaching means. Further, the transfer paper fed by a paper feeding unit 16 is conveyed on a transfer belt 70, and the toner images on the photosensitive drums 21, 22, 23, 24, and 25 are sequentially transferred onto the transfer paper by transfer chargers 61, 62, 63, 64, and 65.

[0128] After the transfer step is completed, the transfer paper is conveyed to a fixing unit 80, and in this fixing unit 80, the transferred toner image is fixed on the transfer paper. After the transfer process, the toner remaining on the photoreceptor drums 21, 22, 23, 24, and 25 is removed by the cleaning units 41, 42, 43, 44, and 45.

[0129] In the apparatus of FIG. 2 and the image forming method using the same, the toner image formed on the photoreceptor drums 21, 22, 23, 24, and 25 is once transferred onto the transfer drum as in FIG. 1, and the toner image is transferred onto the transfer paper by the secondary transfer means 66 and fixed by the fixing unit 80.

[0130] As shown in FIG. 3, the antibacterial and antiviral toner can be provided on a separate transfer drum.

[0131] Next, the configuration around the developing unit will be described. FIG. 4 is an enlarged configuration diagram showing one of the developing units 31, 32, 33, 34, and 35 as five developing and adhering means and one of the photoreceptor drums 21, 22, 23, 24, and 25. Since the configurations are substantially the same except for the different colors of the toners handled, the developing unit 4 and the photoreceptor drum 1 are shown in the figure.

[0132] The developing unit 4 of the present embodiment includes a developing container 2 containing a two-component developer, and a developing sleeve 11 as a developer carrier is rotatably installed at an opening of the developing container 2 facing the photoreceptor drum 1 with a predetermined interval from the photoreceptor 1.

[0133] The developing sleeve 11 is formed of a non-magnetic material in a cylindrical shape and rotates in a direction in which the opposing portion moves in the same direction with respect to the photoreceptor 1 rotating in the direction of the arrow. A magnet roller of a magnetic field generating means is fixedly arranged inside the developing sleeve 11. The magnet roller has five magnetic poles (N1, S1, N2, N3, S2). A regulating blade 10 as a developer regulating member is attached to a portion of the developing container 2 above the developing sleeve 11, and the regulating blade 10 is arranged in non-contact with the developing sleeve 11 toward the vicinity of the magnetic pole (S2) substantially located at the uppermost point in the vertical direction of the magnet roller.

[0134] In the developing container 2, there are provided three developer conveyance paths, namely, a supply conveyance path 2a for housing a supply screw 5 which is a first developer agitation and conveyance means, a recovery screw 6 which is a second developer agitation and conveyance means, and a stirring screw 7 which is a third developer agitation and conveyance means, a recovery conveyance path 2b, and a stirring conveyance path 2c. The supply conveyance path 2a and the stirring conveyance path 2c are arranged in an obliquely upper and lower direction. Further, the recovery conveyance path 2b is arranged on the downstream side of the developing area of the developing sleeve 11, and is arranged substantially horizontally and laterally with respect to the stirring conveyance path 2c.

[0135] The two-component developer accommodated in the developing container 2 is circulated and conveyed through the supply conveyance path 2a, the recovery conveyance path 2b, and the stirring conveyance path 2c by the agitation and conveyance of the supply screw 5, the recovery screw 6, and the stirring screw 7, and is supplied from the supply conveyance path 2a to the developing sleeve 11. The developer supplied to the developing sleeve 11 is pumped up onto the developing sleeve 11 by the magnetic pole (N2) of the magnet roller.

[0136] As the developing sleeve 11 rotates, it is conveyed on the developing sleeve 11 from the magnetic pole (S2) to the magnetic pole (N1) and from the magnetic pole (N1) to the magnetic pole (S1), and reaches the developing area where the developing sleeve 11 and the photoreceptor face each other. On the way of the conveyance, the developer is magnetically regulated in layer thickness in cooperation with the magnetic pole (S2) by the regulating blade 10, and a thin layer of the developer is formed on the developing sleeve 11.

[0137] The magnetic pole (S1) of the magnet roller located in the developing area inside the developing sleeve 11 is the main developing pole, and the developer conveyed to the developing area stands up by the magnetic pole (S1) and contacts the surface of the photoreceptor 1 to develop the electrostatic latent image formed on the surface of the photoreceptor 1.

[0138] The developer that has developed the latent image passes through the developing area as the developing sleeve 11 rotates, returns to the inside of the developing container 2 through the conveyance pole (N3), detaches from the developing sleeve 11 by the repulsive magnetic field of the magnetic poles (N2, N3), and is recovered into the recovery conveyance path 2b by the recovery screw 6.

[0139] The supply conveyance path 2a and the downwardly inclined recovery conveyance path 2b are partitioned by a first partition member 3A. The recovery conveyance path 2b and the stirring conveyance path 2c disposed laterally thereof are partitioned by a second partition member 3B. However, at the downstream portion in the conveyance direction by the recovery screw 6 of the recovery conveyance path 2b, a developer supply opening for supplying the recovered developer to the stirring conveyance path 2c is provided.

[0140] FIG. 5 is a cross-sectional view of the recovery conveyance path 2b and the stirring conveyance path 2c at the downstream portion in the conveyance direction by the recovery screw 6, and an opening 2d for communicating the recovery conveyance path 2b and the stirring conveyance path 2c is provided.

[0141] Also, the supply conveyance path 2a and the stirring conveyance path 2c disposed obliquely downward are partitioned by a third partition member 3C. However, at the upstream and downstream portions in the conveyance direction by the supply screw 5 of the supply conveyance path 2a, developer supply openings for supplying the developer are provided.

[0142] FIG. 6 is a cross-sectional view of the developing unit 4 at the upstream portion in the conveyance direction by the supply screw 5, and an opening 2e for communicating the stirring conveyance path 2c and the supply conveyance path 2a is provided in the third partition member 3C.

[0143] Also, FIG. 7 is a cross-sectional view of the developing unit 4 at the downstream portion in the conveyance direction by the supply screw 5, and an opening 2f for communicating the stirring conveyance path 2c and the supply conveyance path 2a is provided in the third partition member 3C.

[0144] Next, the circulation of the developer in the three developer conveyance paths will be described. FIG. 8 is a schematic diagram of the flow of the developer in the developing unit 4. Each arrow in FIG. 8 indicates the moving direction of the developer. In the supply conveyance path 2a receiving the supply of the developer from the stirring conveyance path 2c, while supplying the developer to the developing sleeve 11, the developer is conveyed to the downstream side in the conveyance direction of the supply screw 5. Then, the surplus developer conveyed to the downstream portion in the conveyance direction of the supply conveyance path 2a without being supplied to the developing sleeve 11 is supplied to the stirring conveyance path 2c through the opening 2f as a first developer supply opening provided in the third partition member 3C.

[0145] Further, the recovered developer that is recovered from the developing sleeve 11 to the recovery conveyance path 2b by the recovery screw 6 and conveyed to the downstream portion in the conveyance direction in the same direction as the developer in the supply conveyance path 2a is supplied from the opening 2d as the second developer supply opening provided in the second partition member 3B to the agitation conveyance path 2c.

[0146] In the agitation conveyance path 2c, the surplus developer and the recovered developer supplied by the agitation screw 7 are agitated and conveyed in a direction opposite to that of the developer in the recovery conveyance path 2b and the supply conveyance path 2a. Then, the developer conveyed to the downstream side in the conveyance direction of the agitation conveyance path 2c is supplied from the opening 2e as the third developer supply opening provided in the third partition member 3C to the upstream portion in the conveyance direction of the supply conveyance path 2a.

[0147] Also, a toner concentration sensor is provided below the agitation conveyance path 2c, and an unillustrated toner replenishment control device is operated by the sensor output to replenish toner from the toner storage portion. In the agitation conveyance path 2c, the agitation screw 7 conveys the toner replenished from the toner replenishment port 3 as needed to the downstream side in the conveyance direction while agitating it with the recovered developer and the surplus developer. When replenishing toner, it is preferable to replenish it upstream of the agitation screw 7 because the agitation time from replenishment to development can be lengthened.

[0148] Thus, in the developing unit 4, since the supply conveyance path 2a and the recovery conveyance path 2b are provided and the supply and recovery of the developer are performed in different developer conveyance paths, the developed developer does not mix into the supply conveyance path 2a. Therefore, it is possible to prevent the toner concentration of the developer supplied to the developing sleeve 11 from decreasing toward the downstream side in the conveyance direction of the supply conveyance path 2a. Also, since the recovery conveyance path 2b and the agitation conveyance path 2c are provided and the recovery and agitation of the developer are performed in different developer conveyance paths, the developed developer does not fall during the agitation. Therefore, since the sufficiently agitated developer is supplied to the supply conveyance path 2a, it is possible to prevent the developer supplied to the supply conveyance path 2a from being insufficiently agitated.

[0149] In this way, it is possible to prevent the toner concentration of the developer in the supply conveyance path 2a from decreasing and to prevent the developer in the supply conveyance path 2a from being insufficiently agitated, so that the image density during development can be made constant.

[0150] Also, in the upstream portion in the conveyance direction of the supply conveyance path 2a shown in FIG. 6, the developer is supplied from the agitation conveyance path 2c arranged obliquely downward to the upper supply conveyance path 2a. The transfer of this developer is to supply the developer to the supply conveyance path 2a by pushing the developer by the rotation of the agitation screw 7, causing the developer to rise and overflowing the developer from the opening 2e. Such movement of the developer applies stress to the developer and contributes to a reduction in the life of the developer.

[0151] In the developing unit 4, by arranging the supply conveyance path 2a obliquely above the agitation conveyance path 2c, the supply conveyance path 2a is provided vertically above the agitation conveyance path 2c, and compared with lifting the developer, the stress on the developer in the upward movement of the developer can be reduced.

[0152] Also, in the downstream portion in the conveyance direction by the supply screw 5 shown in FIG. 7, an opening 2f that communicates the supply conveyance path 2a and the agitation conveyance path 2c is provided to supply the developer from the supply conveyance path 2a arranged above to the agitation conveyance path 2c arranged obliquely downward. Here, the third partition member 3C that partitions the agitation conveyance path 2c and the supply conveyance path 2a extends upward from the lowest point of the supply conveyance path 2a, and the opening 2f is provided at a position above the lowest point.

[0153] Also, FIG. 9 is a cross-sectional view of the developing unit 4 at the most downstream portion in the conveyance direction by the supply screw 5. As shown in FIG. 9, an opening 2g that communicates the agitation conveyance path 2c and the supply conveyance path 2a is provided in the third partition member 3C at a portion downstream of the opening 2f with respect to the conveyance direction by the supply screw 5. Further, the opening 2g is provided above the uppermost portion of the opening 2f.

[0154] In the supply and conveyance path 2a having the openings 2f and 2g, among the developer conveyed in the axial direction of the supply and conveyance path 2a to the opening 2f by the supply screw 5, the developer whose bulk reaches the height of the lowermost part of the opening 2f spills down to the lower stirring and conveyance path 2c through the opening 2f. On the other hand, the developer that does not reach the height of the lowermost part of the opening 2f is supplied to the developing sleeve 11 while being conveyed further downstream by the supply screw 5.

[0155] Therefore, on the downstream side of the opening 2f in the supply and conveyance path 2a, the bulk of the developer gradually becomes lower than the lowermost part of the opening 2f. Since the most downstream part of the supply and conveyance path 2a is a dead end, the bulk of the developer may increase at the most downstream part. However, when it reaches a certain height, the developer is pushed back against the supply screw 5 and returns to the opening 2f. Those that reach the height of the lowermost part of the opening 2f spill down to the lower stirring and conveyance path 2c through the opening 2f.

[0156] As a result, on the downstream side of the opening 2f in the supply and conveyance path 2a, the bulk of the developer does not continue to increase, and it reaches an equilibrium state with a gradient near the lowermost part of the opening 2f. By providing the opening 2g at a position higher than the uppermost part of the opening 2f, that is, at a position higher than this equilibrium state, there is little risk that the opening 2f will be blocked by the developer and ventilation will be insufficient, and sufficient ventilation can be ensured between the stirring and conveyance path 2c and the supply and conveyance path 2a.

[0157] That is, the opening 2g does not function as an opening for supplying the developer between the supply and conveyance path 2a and the stirring and conveyance path 2c, but functions as a ventilation opening for ensuring sufficient ventilation between the supply and conveyance path 2a and the stirring and conveyance path 2c. By providing such a ventilation opening 2g, even if the internal pressure rises in the lower stirring and conveyance path 2c and the recovery and conveyance path 2b communicating with the stirring and conveyance path 2c, sufficient ventilation can be ensured with the upper supply and conveyance path 2a provided with a filter for passing air, and an increase in the internal pressure of the entire developing unit 4 can be suppressed.

[0158] The toner of the present invention can be used in a process cartridge that integrally supports at least one means selected from a photoreceptor, an electrostatic latent image forming means, a developing means, and a cleaning means and is detachable from the main body of an image forming apparatus.

[0159] FIG. 10 shows a schematic configuration of an example of an image forming apparatus including a process cartridge having a developer (also referred to as a developer for electrostatic latent image development) of the present invention. In FIG. 10, the process cartridge includes a photoreceptor 20, an electrostatic latent image forming means 32, a developing means 40, and a cleaning means 61.

[0160] In the present invention, among the components such as the above-described photoreceptor 20, electrostatic latent image forming means 32, developing means 40, and cleaning means 61, a plurality of them are integrally combined as a process cartridge, and this process cartridge is configured to be detachable from the main body of an image forming apparatus such as a copying machine or a printer.

[0161] The operation of an image forming apparatus including a process cartridge having a developer of the present invention will be described as follows. The photoreceptor is rotationally driven at a predetermined peripheral speed. During the rotation process, the photoreceptor receives uniform charging of a positive or negative predetermined potential on its peripheral surface by the electrostatic latent image forming means. Next, it receives image exposure light from an image exposure means such as slit exposure or laser beam scanning exposure. In this way, an electrostatic latent image is sequentially formed on the peripheral surface of the photoreceptor. The formed electrostatic latent image is then toner-developed by the developing means, and the developed toner image is sequentially transferred by the transfer means to a transfer material fed between the photoreceptor and the transfer means in synchronization with the rotation of the photoreceptor from a paper feeding unit.

[0162] The transfer material that has received image transfer is separated from the photoreceptor surface and introduced into an image fixing means for image fixing, and is printed out as a copy outside the apparatus. The surface of the photoreceptor after image transfer is cleaned by removing residual transfer toner by the cleaning means, and after being further discharged, it is repeatedly used for image formation.

[0163] (Toner storage unit) The toner storage unit in the present invention refers to a unit having a function of storing toner, which contains the stored toner. Here, examples of the form of the toner storage unit include a toner storage container, a developing device, a process cartridge, and the like. The toner storage container refers to a container that stores toner. The developing device refers to a device having means for storing and developing toner. The process cartridge refers to a unit that integrates at least an image carrier and developing means, stores toner, and is detachable from an image forming apparatus. The process cartridge may further include at least one selected from charging means, exposure means, and cleaning means.

[0164] By mounting the toner storage unit of the present invention on an image forming apparatus and forming an image, an image can be stably formed using the toner of the present invention, so that an image having antibacterial and antiviral properties can be formed.

[0165] (Printed matter) According to the present invention, a printed matter having an image formed of the toner of the present invention can be obtained. The printed matter of the present invention has a recording medium (base material) and an image formed of the toner of the present invention on the recording medium. By using the toner of the present invention (antibacterial and antiviral toner), a printed matter having antibacterial and antiviral properties can be obtained. As the printed matter of the present invention, it preferably has a layer of color toner formed on the recording medium and a layer of the toner of the present invention formed over the entire surface of the recording medium. Further, it is preferable that the thickness Z [μm] of the toner layer after the fixing step satisfies 2.0X ≤ Z ≤ 2.5X [μm] with respect to the number average particle diameter X of the inorganic antibacterial and antiviral agent.

Examples

[0166] Hereinafter, the present invention will be described more specifically with reference to examples, but the present invention is not limited by these examples. Note that "parts" represents "parts by mass" unless otherwise specified.

[0167] (Manufacture of toner) <Toner A1-1 to A1-5> The raw materials of the toner were as follows.

[0168] · 80 parts of polyester resin 1 (RN-306SF, manufactured by Kao Corporation, weight average molecular weight Mw 7,700, acid value 4 mgKOH / g) · 10 parts of polyester resin 2 (RN-290SF, manufactured by Kao Corporation, weight average molecular weight Mw 11,000, acid value 4 mgKOH / g) · 4 parts of wax dispersant (EXD-001, manufactured by Sanyo Chemical Industries, Ltd.) · 6 parts of monoester wax 1 (melting point mp 70.5 °C) · 0.9 part of zirconium salt A of salicylic acid derivative · 2 parts of inorganic antibacterial and antiviral agent A (Ion Pure ZAF-HS, manufactured by Ishizuka Glass Co., Ltd.) (number average particle diameter 1.8 μm)

[0169] Note that zirconium salt A of salicylic acid derivative used a compound of the following structural formula (1).

[0170] [Chemical formula]

[0171] L1 in structural formula (1) represents the following structure (structural formula (2)).

[0172] [Chemical formula]

[0173] The toner raw materials of the above composition were preliminarily mixed using a Henschel mixer (FM20B, manufactured by Nippon Coke & Engineering Co., Ltd.), and then melted and kneaded at a temperature of 100 to 130 °C using a single-screw kneader (Conida kneader, manufactured by Buss). The obtained kneaded product was cooled to room temperature and then roughly pulverized to 200 μm to 300 μm using a Rotoplex. The coarsely pulverized particles were finely pulverized using a counter jet mill (manufactured by Hosokawa Micron Corporation, 100AFG) while appropriately adjusting the pulverizing air pressure so that the weight average particle size became 4.8 ± 0.3 μm. Then, using an air classifier (manufactured by Matsubo Corporation, EJ-LABO), classification was performed while appropriately adjusting the louver opening so that the weight average particle size was 5.5 μm and the ratio of the weight average particle size to the number average particle size was 1.18 or less, and [toner base particles A1-1] were obtained.

[0174] Next, [toner base particles A1-2] were obtained in the same manner as [toner base particles A1-1], except that 3 parts of the inorganic antibacterial and antiviral agent A were used. Furthermore, with the inorganic antibacterial and antiviral agent A being 4 parts, 5 parts, and 6 parts, [toner base particles A1-3], [toner base particles A1-4], and [toner base particles A1-5] were obtained, respectively.

[0175] Next, for each 100 parts of the toner base particles, 1.6 parts of fumed silica (ZD-30ST, manufactured by Tokuyama Corporation), 0.8 part of fumed silica (UFP-35HH, manufactured by Denki Kagaku Kogyo Kabushiki Kaisha), and 0.8 part of titanium dioxide (MT-150AFM, manufactured by Teika Corporation) were stirred and mixed using a Henschel mixer to produce [toners A1-1] to [toners A1-5]. The weight average particle size Y of the toner is 5.5 μm.

[0176] <Toners A2-1 to A2-5> Next, with the same composition as [toner base particles A1-1], the toner raw materials were preliminarily mixed using a Henschel mixer (manufactured by Nippon Coke & Engineering Co., Ltd., FM20B), and then melted and kneaded at a temperature of 100 to 130 degrees using a single-screw kneader (manufactured by Buss, conical kneader). The obtained kneaded product was cooled to room temperature and then coarsely pulverized to 200 μm to 300 μm using a rotorplex. The coarsely pulverized particles were finely pulverized using a counter jet mill (manufactured by Hosokawa Micron Corporation, 100AFG) while appropriately adjusting the pulverizing air pressure so that the weight average particle size became 6.4 ± 0.3 μm. After that, using an air classifier (manufactured by Matsubo Corporation, EJ-LABO), classification was performed while appropriately adjusting the louver opening so that the weight average particle size was 7.0 μm and the ratio of the weight average particle size to the number average particle size was 1.18 or less, and [toner base particles A2-1] was obtained.

[0177] Furthermore, the addition amounts of the antibacterial and antiviral agent A were set to 3 parts, 4 parts, 5 parts, and 6 parts, and [toner base particles A2-2] to [toner base particles A2-5] were obtained respectively.

[0178] Next, for each 100 parts of the toner base particles, 1.0 part of fumed silica (ZD-30ST, manufactured by Tokuyama Corporation), 0.5 part of fumed silica (UFP-35HH, manufactured by Denki Kagaku Kogyo Kabushiki Kaisha), and 0.5 part of titanium dioxide (MT-150AFM, manufactured by Teika Corporation) were stirred and mixed using a Henschel mixer to produce [toners A2-1] to [toners A2-5]. The weight average particle size Y of the toner is 7.0 μm.

[0179] <Toners A3-1 to A3-5> Next, in the same manner as the production of [toner base particles A1-1], [toner base particles A3-1] to [toner base particles A3-5] were obtained so that the weight average diameter was 9.0 μm. Then, for each 100 parts of the toner base particles, 0.6 part of fumed silica (ZD-30ST, manufactured by Tokuyama Corporation), 0.3 part of fumed silica (UFP-35HH, manufactured by Denki Kagaku Kogyo Kabushiki Kaisha), and 0.3 part of titanium dioxide (MT-150AFM, manufactured by Teika Corporation) were stirred and mixed using a Henschel mixer to produce [toners A3-1] to [toners A3-5]. The weight average particle size Y of the toner is 9.0 μm.

[0180] <Toners B1-1 to B3-5, Toners C1-1 to C3-5, Toners D1-1 to D3-5> In the same manner as the toner A group, the inorganic antibacterial and antiviral agent A was changed to inorganic antibacterial and antiviral agents B to F. Furthermore, the addition amounts of inorganic antibacterial and antiviral agents B to F were each changed to 2 to 6 parts, and furthermore, the weight average particle diameters of the toner were each changed to 5.5 μm, 7.0 μm, and 9.0 μm to produce [toner B1-1] to [toner B3-5], [toner C1-1] to [toner C3-5], and [toner D1-1] to [toner D3-5].

[0181] <Details of Inorganic Antibacterial and Antiviral Agents A to F> The details of inorganic antibacterial and antiviral agents A to F (antibacterial agents A to F) are as follows. · Inorganic antibacterial and antiviral agent A: Ion Pure ZAF-HS manufactured by Ishizuka Glass Co., Ltd. (Number average particle diameter X: 1.8 μm, antibacterial metals: including Ag and Zn) (Particle shape: no cubes and rectangular parallelepipeds, carrier: silicon-based glass) · Inorganic antibacterial and antiviral agent B: Ion Pure WPA manufactured by Ishizuka Glass Co., Ltd. (Number average particle diameter X: 1.6 μm, antibacterial metals: including Ag and Zn) (Particle shape: no cubes and rectangular parallelepipeds, carrier: silicon-based glass) · Inorganic antibacterial and antiviral agent C: Zeomic AJ10N manufactured by Sinanozyme Co., Ltd. (Number average particle diameter X: 2.3 μm, antibacterial metals: including Ag and Zn) (Particle shape: cube, carrier: zeolite) · Inorganic antibacterial and antiviral agent D: Novaron VZF200 manufactured by Toagosei Co., Ltd. (Number average particle diameter X: 2.8 μm, antibacterial metal: including Zn) (Particle shape: no cubes and rectangular parallelepipeds) · Inorganic antibacterial and antiviral agent E: Novaron VZN300 manufactured by Toagosei Co., Ltd. (Number average particle diameter X: 1.3 μm, antibacterial metal: including Zn) (Particle shape: no cubes and rectangular parallelepipeds) · Inorganic antibacterial and antiviral agent F: Novaron IV200 manufactured by Toagosei Co., Ltd. (Number average particle diameter X: 0.9 μm, antibacterial metal: including Zn) (Shape of particles: including cubes and rectangular parallelepipeds, 20% or less)

[0182] In addition, the SEM image of antibacterial agent C is shown in Fig. 11. In the figure, (a) and (b) are images obtained at the same scale and are observations of different locations respectively. (c) and (d) are images obtained at the same scale and are observations of different locations respectively. The antibacterial agent C consisted of particles with a cubic shape made of an inorganic antibacterial and antiviral agent.

[0183] The formulations of each toner are shown in Tables 1 to 3. In addition, when [toner A1-1] to [toner A1-5] are described together, they may be referred to as [toner A1]. Also, when [toner A2-1] to [toner A2-5] are described together, they may be referred to as [toner A2], and when [toner A3-1] to [toner A3-5] are described together, they may be referred to as [toner A3]. The same applies to [toner B1] to [toner B3], [toner C1] to [toner C3], [toner D1] to [toner D3], [toner E1] to [toner E3], and [toner F1] to [toner F3].

[0184] (Evaluation) The following evaluations were performed on the obtained toner. In the following evaluations, some evaluations were performed by forming an image using the obtained toner and evaluating the image. Table 4 shows the relationship between the number average particle diameter X of antibacterial agents A to F and the thickness Z [μm] of the toner layer after the fixing process. In Table 4, those satisfying 2.0X ≤ Z ≤ 2.5X [μm] are marked as "〇", and those not satisfying are marked as "×". In the table, the numerical values shown in [mg / cm 2 represent the toner adhesion amount on the substrate. Also, the column below the toner adhesion amount represents the thickness Z [μm] of the antibacterial and antiviral toner layer (for example, 3.0 [μm], etc.).

[0185] <Manufacturing yield evaluation> In the production of each toner base particle, the production yield up to the pulverization and classification process was evaluated. A yield of 70% or more was rated as "〇" (good), and less than 70% was rated as "×" (bad). The results are shown in Tables 5 to 7. As shown in the table, for [Toner C1], [Toner D1], and [Toner D2], the yield was less than 70%, and the yield significantly decreased. Considering the toners with a yield of less than 70%, in the relationship between the number average particle size X [μm] of the antibacterial and antiviral agent and the weight average particle size Y [μm] of the toner, 3X ≤ Y was not satisfied. That is, it can be seen that a good production yield cannot be obtained when 3X > Y.

[0186] <Preparation of Two-Component Developer> <<Preparation of Carrier>> The raw materials for the carrier were as follows. · 100 parts of silicone resin (organostraight silicone) · 100 parts of toluene · 5 parts of γ-(2-aminoethyl)aminopropyltrimethoxysilane · 10 parts of carbon black

[0187] The mixture of the above raw materials was dispersed with a homomixer for 20 minutes to prepare a coating layer forming liquid. Using the coating layer forming liquid and Mn ferrite particles with a weight average particle size of 35 μm as the core material, the temperature in the fluidized bed was controlled at 70 °C each, and coating and drying were performed by a fluidized bed coating device so that the average film thickness became 0.20 μm on the surface of the core material. Next, it was fired in an electric furnace at 180 °C for 2 hours to obtain [Carrier].

[0188] <<Preparation of Two-Component Developer>> Among the above-produced [Toner A1] to [Toner F3], a two-component developer was prepared using the toners with a "〇" in the base production yield and the above [Carrier]. In the preparation of the two-component developer, the toner and the carrier were uniformly mixed at 48 rpm for 5 minutes using a turbular mixer (manufactured by Willy E. Bachofen (WAB)) and charged to prepare each two-component developer. The mixing ratio of the toner and the carrier was adjusted according to the toner concentration (5% by mass) of the initial developer of the evaluation machine.

[0189] <Electrification property evaluation> For each of the developers (two-component developers) prepared as described above, the following electrification property evaluation was carried out. Each developer was put into the developing unit of Ricoh monochrome MFP "RICOH MP 305+ SPF", and after the developing unit was idled for 10 minutes in an environment of 20°C and 50% RH, 10°C and 20% RH, and 35°C and 85% RH, the toner charge amount was measured. When the charge amount in the environment of 20°C and 50% RH is MMq, the charge amount in the environment of 10°C and 20% RH is LLq, and the charge amount in the environment of 35°C and 85% RH is HHq, (|LLq - MMq| + |MMq - HHq|) / MMq ··· Equation (1) When the value of Equation (1) is less than 1, the electrification property was regarded as stable against the environment and marked as "〇" (qualified). On the other hand, when the value of Equation (1) is 1 or more, the electrification property was regarded as unstable against the environment and marked as "×" (unqualified). If the electrification property is unstable against the environment, the amount of toner adhering to the substrate (recording medium) will become unstable due to environmental changes, and a stable antibacterial and antiviral property cannot be obtained.

[0190] The results of the electrification property evaluation are shown in Tables 5 to 7. As shown in the table, when the number average particle size of the antibacterial and antiviral agent is less than 1.5 μm, and when the content of the antibacterial and antiviral agent in the toner exceeds 5.0% by mass, it can be seen that the electrification property is affected. For example, among [Toner E1] to [Toner F3] using Antibacterial Agent E or Antibacterial Agent F, some have unqualified electrification property evaluations. Also, even when the number average particle size of the antibacterial and antiviral agent is 1.8 μm or less, if the content exceeds 5.0% by mass, there are those with unqualified electrification properties (for example, [Toner A1-5], [Toner B1-5], etc.).

[0191] <Transmittance evaluation> Next, for the developers that obtained "〇" (qualified) in the electrification property evaluation, images were formed as follows, and the transmittance evaluation was carried out. With the Ricoh monochrome MFP "RICOH MP 305+ SPF", the process conditions such as the development conditions were adjusted, and solid images were printed on A4-sized OHP sheets (Kokuyo OHP Film VF-1411N) with the following toner adhesion amounts. Note that the thickness of the adhesion film Z (the thickness Z of the antibacterial and antiviral toner layer) was measured by observing the cross-section of a thin slice cut out from the sheet and vertically cut with a razor using an electron microscope.

[0192] [Toner adhesion amount] ·0.38 ± 0.02 mg / cm 2 (Adhesion film thickness 3.0 μm) ·0.45 ± 0.02 mg / cm 2 (Adhesion film thickness 3.5 μm) ·0.51 ± 0.02 mg / cm 2 (Adhesion film thickness 4.0 μm) ·0.58 ± 0.02 mg / cm 2 (Adhesion film thickness 4.5 μm) ·0.64 ± 0.02 mg / cm 2 (Adhesion film thickness 5.0 μm)

[0193] The transmittance of the solid image in the wavelength range from 350 nm to 700 nm was measured using an ultraviolet-visible near-infrared spectrophotometer V-660 (manufactured by JASCO Corporation). As shown in Fig. 12, nine 50 mm × 50 mm samples were evenly cut out from within the A4 size, and these samples were measured, and the lowest transmittance value was adopted as the result. The evaluation criteria were as follows. The results are shown in Tables 5 to 7.

[0194] [Evaluation criteria] When the transmittance of the wavelength with the lowest transmittance in the above wavelength range was 25% or more, it was rated as "〇" (pass), and when it was less than 25%, it was rated as "×" (fail). When the transmittance was less than 25%, the image printed under the layer formed by the toner containing the antibacterial and antiviral agent became unclear.

[0195] [Solid image evaluation] Next, among the nine cut samples of each printed matter taken out in the above transmittance evaluation, the side of the sample with the lowest transmittance was observed for the toner adhesion state of the solid image using a laser microscope (OPTELIC H1200 manufactured by Lasertec Corporation). As the evaluation criteria, a state where the base material is completely covered with toner was defined as "〇" (qualified), and a state where there is a part where toner is not adhered at all was defined as "×" (unqualified).

[0196] The results are shown in Tables 5 to 7. As shown in the table, all toners with a weight average particle diameter of the toner of 5.5 μm were "〇" (qualified). That is, among [toner A1], [toner B1], [toner E1], and [toner F1], those for which the evaluation was conducted were "〇". On the other hand, among the toners with a weight average particle diameter of the toner of 7.0 μm and 9.0 μm, some were "×" (unqualified). As shown in the table, when the weight average particle diameter of the toner is 7.0 μm, the toner adhesion amount is 0.38 mg / cm 2 and when the weight average particle diameter of the toner is 9.0 μm, the toner adhesion amounts of 0.38 mg / cm 2 and 0.45 mg / cm 2 were "×" (unqualified).

[0197] <Evaluation of the surface exposure state of the antibacterial and antiviral agent> Next, in the samples that were "〇" (qualified) in the above solid image evaluation, the surface exposure state of the antibacterial and antiviral agent was evaluated as follows. In the surface exposure state evaluation, in the sample to be evaluated, the antibacterial and antiviral agent on the image surface was observed using a scanning electron microscope (SEM: SU8230 manufactured by Hitachi, Ltd.) and an energy dispersive X-ray analyzer (EDX: XFlash FlatQUAD 5060F manufactured by Bruker). Among the samples for which the transmittance evaluation was conducted, sample sections were obtained from the sample with the lowest transmittance. From this sample section, 50 sites in a range of 60 μm × 60 μm of 10 observation pieces randomly selected from 5 locations where 20 or more antibacterial and antiviral agents could be observed were evaluated.

[0198] In the evaluation, the surface of the image was photographed by SEM. For EDX, the following conditions were set: the filter of the detector was selected as 1 + 6μm Mylar, and it was set for at least 180 s in the hypermap and mapped.

[0199] [EDX Observation Conditions] Acceleration voltage: 15 kv Emission: 25 mV Probe current: High Condenser lens: 1.0 W.D.: 11.0 Image magnification: 2000 times SE(U) + SE(L)

[0200] [Evaluation Criteria] ◎: 20 or more antibacterial and antiviral agents can be observed at all sites 〇: 10 or more antibacterial and antiviral agents can be observed at all sites ×: There is even one site with 10 or fewer

[0201] The results are shown in Tables 5 to 7. As shown in the table, toner image samples using antibacterial and antiviral agents with an average particle size of 1.3 μm or less tended to have an unstable surface exposure state. That is, [Toner E1] to [Toner F3] were rated as "×". In addition, among toners using other antibacterial and antiviral agents, those with a low content of antibacterial and antiviral agents (for example, [Toner A1-1], etc.) and those with a large toner adhesion amount (for example, an adhesion amount of 0.64 mg / cm 2 etc.) were rated as "×".

[0202] Note that Fig. 13 shows the EDX measurement results of the Al element on the image surface when an image was formed at an adhesion amount of 0.58 ± 0.02 mg / cm using [Toner C2-3]. Symbol 101 indicates the antibacterial agent, and symbol 102 indicates other materials in [Toner C2-3]. The figure shows that the antibacterial agent containing the Al element is exposed to a certain extent on the image surface. 2

[0203] ​<Stability Test (Printing Stability Test)> For the toners that obtained good results (above "〇") in all of the above items (mother body manufacturing yield, chargeability evaluation, transmittance evaluation, surface exposure evaluation), the following stability test was conducted. The stability test was evaluated by performing continuous printing of 1,000 sheets with the following toner adhesion amounts using the Ricoh monochrome MFP model. The evaluation criteria were as follows.

[0204] [Toner Adhesion Amount] · Toner with a toner weight average particle diameter of 5.5 μm: Adhesion amount 0.38 ± 0.02 mg / cm 2 · Toner with a toner weight average particle diameter of 7.0 μm: Adhesion amount 0.45 ± 0.02 mg / cm 2 · Toner with a toner weight average particle diameter of 9.0 μm: Adhesion amount 0.51 ± 0.02 mg / cm 2

[0205] [Evaluation Criteria] For the 10 solid images from the 991st to the 1000th sheets in continuous printing, if there were no streaks or spot-like missing areas, it was regarded as "〇" (qualified), and if there were streaks or spot-like missing areas, it was regarded as "×" (unqualified).

[0206] [Evaluation Results of Stability Test] The results are shown in Tables 5 and 6. As a result, for those evaluated with [Toner A1] to [Toner A3], [Toner B1], [Toner C2], and [Toner C3] in the stability test, good results were obtained. On the other hand, in [Toner D3-3], streaks that seemed to be damage to the photoreceptor occurred, resulting in a failure "×".

[0207] <Antibacterial Test> As a confirmation of antibacterial properties, the following antibacterial test was conducted on the following image samples.

[0208] [Image Samples] · Image sample with an adhesion amount of 0.58 ± 0.02 mg / cm of [Toner A1-2] 2 of the image sample · Adhesion amount of [Toner A2-2]: 0.58 ± 0.02 mg / cm 2 of the image sample · Adhesion amount of [Toner B1-2]: 0.51 ± 0.02 mg / cm 2 of the image sample · Adhesion amount of [Toner C2-1]: 0.64 ± 0.02 mg / cm 2 of the image sample · Adhesion amount of [Toner C2-2]: 0.64 ± 0.02 mg / cm 2 of the image sample · Adhesion amount of [Toner C3-2]: 0.64 ± 0.02 mg / cm 2 of the image sample

[0209] [Antibacterial test method] The antibacterial test was carried out in accordance with JIS Z 2801:2012 by the following method. (1) Pre-culture of test bacteria After culturing the test bacteria (Staphylococcus aureus, Escherichia coli) on a normal agar medium, further subculture is carried out. (2) Preparation of test bacterial solution The cells of the test bacteria after culturing are dispersed in a dilution of a normal broth medium to prepare a concentration of 2.5 - 10×10 5 cells / ml. (3) Inoculation of test bacterial solution After dropping 0.4 ml of the bacterial solution onto the test surface of the test pieces (5 cm × 5 cm processed and unprocessed products), cover the bacterial solution with a polyethylene film (4 cm × 4 cm) from above to make the bacterial solution adhere to the test pieces. (4) Measurement of viable bacteria count of test pieces immediately after inoculation Measure the viable bacteria count of the unprocessed test pieces. (5) Cultivation The test pieces inoculated with the bacterial solution are cultured at 35°C and a relative humidity of 90% or more for 24 ± 1 hours. (6) Measurement of viable bacteria count of test pieces after cultivation Measure the viable bacteria count of the test pieces (antibacterial processed and unprocessed). (7) Test results It is judged that there is an antibacterial effect when the antibacterial activity value R is 2.0 or more. R = (Ut - U0) - (At - U0) = Ut - At R: Antibacterial activity value U0: Average value of the logarithm of the viable cell count immediately after inoculation of the unprocessed test piece Ut: Average value of the logarithm of the viable cell count of the unprocessed test piece after 24 hours At: Average value of the logarithm of the viable cell count of the antibacterial processed test piece after 24 hours

[0210] [Results of antibacterial test] · Adhesion amount of [toner A1-2]: 0.58 ± 0.02 mg / cm 2 of the image: With antibacterial effect · Adhesion amount of [toner A2-2]: 0.58 ± 0.02 mg / cm 2 of the image: With antibacterial effect · Adhesion amount of [toner B1-2]: 0.51 ± 0.02 mg / cm 2 of the image: With antibacterial effect · Adhesion amount of [toner C2-1]: 0.64 ± 0.02 mg / cm 2 of the image: Without antibacterial effect · Adhesion amount of [toner C2-2]: 0.64 ± 0.02 mg / cm 2 of the image: With antibacterial effect · Adhesion amount of [toner C3-2]: 0.64 ± 0.02 mg / cm 2 of the image: With antibacterial effect

[0211]

Table 1

[0212]

Table 2

[0213]

Table 3

[0214]

Table 4

[0215]

Table 5

[0216]

Table 6

[0217]

Table 7

[0218] According to the above results, according to this embodiment, toner can be stably manufactured, and an image having antibacterial and antiviral properties can be stably formed by using toner having good chargeability.

Explanation of Signs

[0219] 14 Image processing unit (IPU) 15 Writing unit 16 Paper feeding unit 21 Black (Bk) toner, photosensitive drum for developer 22 Yellow (Y) toner, photosensitive drum for developer 23 Magenta (M) toner, photosensitive drum for developer 24 Cyan (C) toner, photosensitive drum for developer 25 Antibacterial and antiviral toner, photosensitive drum for developer

Prior Art Documents

Patent Documents

[0220]

Patent Document 1

Patent Document 2

Patent Document 3

Patent Document 4

Claims

1. An electrostatic latent image forming step of forming an electrostatic latent image on an electrostatic latent image carrier, A developing step of developing the electrostatic latent image using toner to form a visible image, A transfer step of transferring the visible image onto a recording medium, An image forming method comprising a fixing step of fixing the transferred image on the recording medium, wherein The toner contains toner base particles and an external additive, and satisfies all of the following conditions (1) to (3), The toner base particles contain a binder resin, a release agent, and particles composed of an inorganic antibacterial and antiviral agent, When the number average particle diameter of the particles composed of the inorganic antibacterial and antiviral agent is X [μm] and the thickness of the layer of the toner fixed on the recording medium is Z [μm], 2.0X ≤ Z ≤ 2.5X [μm] is satisfied. An image forming method characterized by that. [Condition] (1) The number average particle diameter X of the particles composed of the inorganic antibacterial and antiviral agent is 1.5 ≤ X ≤ 2.5 [μm] (2) When the weight average particle diameter of the toner is Y, 3X ≤ Y ≤ 4X [μm] (3) The content of the inorganic antibacterial and antiviral agent in the toner is 2.8% by mass or more and 5.0% by mass or less

2. The image forming method according to claim 1, characterized in that when the toner is an antibacterial and antiviral toner, the antibacterial and antiviral toner and a color toner different from the antibacterial and antiviral toner are used.

3. The image forming method according to claim 2, characterized in that a layer of the color toner is formed on the recording medium, and further, a layer of the antibacterial and antiviral toner is formed on the entire surface of the recording medium thereon.

4. An electrostatic latent image carrier, Electrostatic latent image forming means for forming an electrostatic latent image on the electrostatic latent image carrier, Developing means for developing the electrostatic latent image using toner to form a visible image, Transfer means for transferring the visible image onto a recording medium, An image forming apparatus comprising fixing means for fixing the transferred image on the recording medium, wherein The toner contains toner base particles and an external additive, and satisfies all of the following conditions (1) to (3), The toner base particles contain a binder resin, a release agent, and particles composed of an inorganic antibacterial and antiviral agent, When the number average particle diameter of the particles composed of the inorganic antibacterial and antiviral agent is X [μm] and the thickness of the layer of the toner fixed on the recording medium is Z [μm], 2.0X ≤ Z ≤ 2.5X [μm] is satisfied. An image forming apparatus characterized by that. [Condition] (1) The number average particle diameter X of the particles composed of the inorganic antibacterial and antiviral agent is 1.5 ≦ X ≦ 2.5 [μm]. (2) When the weight average particle diameter of the toner is Y, 3X ≦ Y ≦ 4X [μm]. (3) The content of the inorganic antibacterial and antiviral agent in the toner is 2.8% by mass or more and 5.0% by mass or less.

5. The image forming apparatus according to claim 4, further comprising the antibacterial and antiviral toner and a color toner different from the antibacterial and antiviral toner when the toner is an antibacterial and antiviral toner.

Images