toner

Abstract

To provide toner that has antibacterial agent particles on a surface of a toner particle, suppresses transition of the antibacterial agent particles from the surface of the toner particle included in the toner and can develop sufficient antibacterial properties with a smaller amount of antibacterial agent, and a developer including the same.SOLUTION: Antibacterial agent particles are present in at least a surface of a toner particle. In a surface image of the toner particle obtained by causing a specific rubber roller to carry toner on its outer peripheral surface, bringing a surface of a flat plate made of SUS304 and having a specific surface roughness into contact with the outer peripheral surface of the rubber roller and rubbing these surfaces with each other, and subsequently conducting surface observation by using a scanning electron microscope, when the average number of the antibacterial agent particles present in the surface image per toner particle is defined as Y, and the average number of the antibacterial agent particles present in the surface image per toner particle before the rubbing as X, the Y and the X satisfy the following formula (1). (1) 0.7≤Y / X≤1.0.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present invention relates to a toner, more particularly to a toner capable of imparting antibacterial properties to media outputted using an electrophotographic method, and particularly to a toner for electrophotography. [Background technology]

[0002] In recent years, the COVID-19 pandemic has also triggered an increased demand for antiviral and antibacterial properties. This demand is particularly strong for items that are touched by an unspecified number of people. In the printing field, methods have been disclosed in which antibacterial paper is imparted with antibacterial properties by coating the entire surface of the paper with a resin containing an antibacterial agent, and a method of imparting antibacterial properties by incorporating (blending) an antibacterial agent into a clear toner and developing the toner using an electrophotographic method. Furthermore, a method has been disclosed in which Ag microparticles, an antibacterial agent, are externally added to a toner or developer, and the toner is developed on a printing medium to impart antibacterial properties (Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2005-78095 Summary of the Invention [Problem to be solved by the invention]

[0004] However, when using any of the above techniques, problems arise. First, in order for the antibacterial properties to be exerted on the target, the antibacterial agent must be present on the outermost surface that comes into contact with bacteria, due to the mechanism of the exertion of antibacterial properties. Antibacterial paper, which is entirely coated with a resin containing an antibacterial agent, can guarantee the antibacterial properties of the paper itself. However, when printing is performed on the antibacterial paper, the printed area, which does not have antibacterial properties, covers the surface of the antibacterial paper, and the area covered by the printed area cannot exhibit antibacterial properties. In addition, in a method in which an antibacterial agent is incorporated into a transparent toner and the toner is developed by an electrophotographic method to impart antibacterial properties, the antibacterial agent is contained throughout the toner. Therefore, as described above, although the antibacterial agent must be present on the outermost surface that comes into contact with bacteria due to the mechanism of antibacterial properties, the proportion of the antibacterial agent present on the outermost surface is low, increasing the possibility that a large amount of antibacterial agent exists that does not contribute to the antibacterial properties. As a result, it becomes necessary to incorporate a large amount of antibacterial agent into the toner, which leads to increased costs. Furthermore, Patent Document 1 proposes a method of adding Ag particles, an antibacterial agent, to a toner and developing the toner to impart antibacterial properties to a print medium. However, when using this method, the added Ag particles migrate from the toner surface in areas where the toner is subjected to stress, such as friction, during the electrophotographic process, and there is a risk that almost no Ag particles remain when the toner is actually fixed to the media. This could result in the media not exhibiting antibacterial properties. Furthermore, if Ag particles are added based on the required amount of Ag particles after fixing to the media, the amount of Ag particles added must be increased, leading to significant cost increases. Furthermore, the inventors have discovered that the conductive Ag particles used as an antibacterial agent can reduce the toner's chargeability, resulting in image defects such as fogging. The object of the present invention is to provide a toner containing toner particles having an antibacterial agent on the particle surface, which, when the toner is output onto a medium through an electrophotographic process, can suppress the migration of the antibacterial agent (particles) from the toner during the electrophotographic process, thereby enabling sufficient antibacterial properties to be exhibited with a smaller amount of the antibacterial agent, thereby contributing to cost reduction. It is also possible to provide a developer using such a toner. [Means for solving the problem]

[0005] In order to achieve the above object, a first invention of the present application is a toner having toner particles and an external additive, the external additive contains at least antibacterial agent particles, the antibacterial agent particles are present at least on the surface of the toner particles, The toner was applied at a concentration of 0.3 μL / cm on the outer peripheral surface of a rotatable rubber roller having a diameter of 10 mm. 2 The surface of a flat plate made of SUS304, having an arithmetic mean roughness Ra of 0.15 μm or less and a ten-point mean roughness Rz of 1.0 μm or less, is brought into contact with the outer circumferential surface of the rubber roller at a contact pressure of 0.04 MPa, and the rubber roller is rotated 5 times at 30 rpm to rub the surface, and then the surface is observed using a scanning electron microscope to obtain a surface image of the toner particles, where Y is the average number of the antibacterial agent particles present in the surface image per toner particle, and X is the average number of the antibacterial agent particles present in the surface image per toner particle in the surface image of the toner particles obtained by observing the surface using a scanning electron microscope before the rubbing, The Y and the X satisfy the following formula (1): The toner is characterized by the above. 0.7≦Y / X≦1.0 (1) [Effects of the Invention]

[0006] As described above, according to the present invention, it is possible to make the antibacterial agent particles present on at least the surface of the toner particles in a quantity necessary and sufficient to exhibit antibacterial properties, more so than any of the prior arts disclosed so far, and to make the antibacterial agent particles remain on the surface of the toner particles until they are fixed to the medium. As a result, it is possible to provide a toner that exhibits excellent antibacterial properties at low cost. [Brief explanation of the drawings]

[0007] [Figure 1] 1A and 1B are cross-sectional views showing an example of a rubber roller, in which (a) is a cross-sectional view in a direction parallel to the axial direction, and (b) is a cross-sectional view in a direction perpendicular to the axial direction. [Figure 2] FIG. 1 is a cross-sectional view of an example of an apparatus used to uniformly coat toner as a preliminary step in evaluating the migration of antibacterial agent particles. [Figure 3] FIG. 1 is a cross-sectional view of an example of an apparatus used to evaluate the migration of antibacterial agent particles. DETAILED DESCRIPTION OF THE INVENTION

[0008] An example of an embodiment of the toner according to the present invention will be described below in detail with reference to the accompanying drawings. It should be noted that the present invention is not limited to the disclosed embodiment, and various modifications can be made without departing from the spirit and scope of the invention. Therefore, the dimensions, materials, shapes, and relative positions of the components described in this embodiment can be appropriately changed depending on the configuration of the device to which the invention is applied and various conditions. Furthermore, in the drawings described below, components having the same functions are designated by the same reference numerals, and their descriptions may be omitted or simplified.

[0009] In the present invention, unless otherwise specified, the expressions "xx or more and xx or less" and "xx to xx" representing a numerical range mean a numerical range including the lower and upper limits, which are the endpoints. When a numerical range is described in stages, the upper and lower limits of each numerical range can be combined arbitrarily.

[0010] [Features of the present invention] The present inventors believe that the mechanism by which the effects of the present invention are exerted is as follows.

[0011] <Requirements for exhibiting antibacterial properties> "Antibacterial" refers to the inhibition of bacterial growth on the surface of a product. In addition, "antibacterial properties" are defined in the Japanese Industrial Standards (JIS) as a product having antibacterial effects when the bacterial growth rate is 1 / 100 or less (antibacterial activity value of 2 or more) compared to the surface of an untreated product (JIS Z 2801).

[0012] Although the mechanism by which antibacterial properties are expressed is not completely clear, it is said that direct contact between bacteria and antibacterial agents destroys the bacterial cell walls, inactivating the bacteria.

[0013] As a result of intensive research by the present inventors, it has been found that in order to efficiently exhibit antibacterial properties, it is important that a necessary and sufficient amount of antibacterial agent (component having antibacterial properties) is present on the outermost surface that comes into contact with bacteria.

[0014] Furthermore, it has been found that in order to impart antibacterial properties to media using toner efficiently and cost-effectively, it is preferable to externally add an antibacterial agent to the surface (particularly the outermost surface) of the toner particles that make up the toner, and that it is preferable that the layer of antibacterial agent formed on the surface of the toner particles is thin.

[0015] <Antibacterial agent on the surface of toner particles in electrophotography process> An external additive such as silica is usually attached to the surface of toner particles for the purpose of improving chargeability and fluidity in a developing device (or developing apparatus). For example, Japanese Patent Application Laid-Open No. 2000-122335 proposes that fine particles be present on the surface of toner particles. Furthermore, Japanese Patent Application Laid-Open No. 2005-234274 proposes that an external additive be added to recesses on the surface of toner particles.

[0016] However, toner is subjected to various external loads and stresses from inside the developing device until it is fixed to the media, which causes the fine particles and external additives present on the surface of the toner particles to gradually migrate from the toner particle surface.

[0017] Therefore, the inventors considered that the antibacterial agent added as an external additive is prevented as much as possible from migrating from the surface of the toner particles until it is fixed to the media where antibacterial properties are to be exhibited.

[0018] From the above viewpoints, the present inventors have conducted further studies and have found that when a toner having toner particles and an external additive, wherein the external additive contains at least antibacterial agent particles, the antibacterial agent particles are present at least on the surface of the toner particles, and the toner is evaluated by a specific test or measurement method, more specifically, when the amount (transferred amount) of antibacterial agent particles is measured (counted in number) before and after applying a specific load to the toner and the average values ​​are X and Y, and X and Y satisfy a specific relational expression, the toner can suppress the migration of the antibacterial agent (particles) from the surface of the toner particles and exhibit excellent antibacterial properties, thereby achieving the present invention.

[0019] That is, the present invention is A toner having toner particles and an external additive, the external additive contains at least antibacterial agent particles, the antibacterial agent particles are present at least on the surface of the toner particles, The toner was applied at a concentration of 0.3 μL / cm on the outer peripheral surface of a rotatable rubber roller having a diameter of 10 mm. 2 The surface of a flat plate made of SUS304, having an arithmetic mean roughness Ra of 0.15 μm or less and a ten-point mean roughness Rz of 1.0 μm or less, is brought into contact with the outer circumferential surface of the roller at a contact pressure of 0.04 MPa, and the roller is rotated 5 times at 30 rpm to rub the surface, and then the surface is observed using a scanning electron microscope to obtain a surface image of the toner particles, where Y is the average number of the antibacterial agent particles present in the surface image per toner particle, and X is the average number of the antibacterial agent particles present in the surface image per toner particle in the surface image of the toner particles obtained by observing the surface using a scanning electron microscope before the rubbing, The Y and the X satisfy the following formula (1): The present invention relates to a toner characterized by the above-mentioned. 0.7≦Y / X≦1.0 (1)

[0020] <Method for evaluating migration of antibacterial particles> The migration of antibacterial particles from the surface of toner particles can be evaluated by observing the surface of the toner particles with a scanning electron microscope (SEM). This evaluation method is described below.

[0021] (Preparation (Method of Carrying Toner on the Outer Surface of a Rubber Roller)) To evaluate the migration of antibacterial particles from the surface of toner particles, the toner is first carried on the outer surface of a rubber roller (rotating body). 2 The outer circumferential surface of the rubber roller is preferably coated with the solution uniformly.

[0022] A cross-sectional view of an example of a rubber roller is shown in FIG. 1. In FIG. 1, the rubber roller 1 is formed by coating (covering) a 4 mm thick conductive silicone rubber layer (L4) on the outer surface of a SUS cylindrical core (mandrel) 11 having a core diameter L3 of 6 mm and a length L1 of 260 mm. The outermost layer is then coated (covered) with a 10 μm thick urethane resin (not shown), forming a rubber layer (conductive silicone rubber layer) 13. In FIG. 1, support portions 12, 12 each having an axial length L2 of 13 mm are formed by cutting a predetermined length from both longitudinal ends (axial end sides of the core) of the rubber layer 13 so that the rubber roller 1 can be rotatably supported by the core portion (axial end portions) in a later operation. Therefore, as will be described later, the rubber roller 1 is supported by a coating device 200 so as to be rotatable in a predetermined direction around the axis of the core 11.

[0023] The method for uniformly carrying (coating) the toner on the outer peripheral surface of the rubber roller may be any known method. For example, the simplest method is to use a regulating member for regulating the coating amount of the supplied toner. Note that such a regulating member may be one used in electrophotography processes.

[0024] FIG. 2 shows a cross-sectional view of a coating device 200 that uniformly coats the outer circumferential surface of a rubber roller with toner.

[0025] 2, the coating device 200 contains the toner T therein and includes a rubber roller 1, a toner supply roller 202, and a regulating member 203. The toner supply roller 202 has a cylindrical or columnar shape. The regulating member 203 regulates the amount of coating of the toner T supplied by the toner supply roller 202, and is made of a plate-like body having a required length and thickness.

[0026] In FIG. 2, coating device 200 supports both longitudinal (axial) ends of rubber roller 1 and toner supply roller 202 (not shown) so that they can rotate in a predetermined direction. Toner supply roller 202 is disposed in coating device 200 so as to come into contact with toner T and is configured to be rotatable in a clockwise direction (the direction of arrow D in the figure). With its outer circumferential surface in contact with the outer circumferential surface of toner supply roller 202, rubber roller 1 is driven to rotate in a counterclockwise direction (the direction of arrow E in the figure) relative to toner supply roller 202. Therefore, toner T in coating device 200 is carried and transported by toner supply roller 202 and supplied and carried on the outer circumferential surface of rubber roller 1. The toner T carried on the outer circumferential surface of rubber roller 1 is then transported in the direction of arrow E in FIG. 2 until it reaches a position facing regulating member 203.

[0027] The amount of toner T coated on the outer peripheral surface of the rubber roller 1 is regulated by the regulating member 203 at this position; specifically, the toner T is regulated so that a layer having a thickness equal to the width between the outer peripheral surface of the rubber roller 1 and the surface of the regulating member 203 is formed, thereby making the toner T uniform.

[0028] Thereafter, as the rubber roller 1 rotates, the toner T passes through the regulating member 203 and is uniformly coated on the outer circumferential surface of the rubber roller 1 .

[0029] 2, the regulating member 203 has a toner T intake portion 203L formed so as to extend from the position facing the rubber roller 1 toward the tip side (rubber roller 1 side). 2In order to coat the toner T, it is possible to arbitrarily adjust the length of the toner T intake portion 203L of the regulating member 203, the surface roughness of the rubber roller 1, and the pressure with which the regulating member 3 contacts the rubber roller 1. It is preferable to set the contact pressure between the rubber roller 1 and the regulating member 3 at this time to be lower than the pressure (contact pressure) of 0.04 MPa in the actual measurement described later.

[0030] The coating (carrying) amount of toner T is 0.3 μL / cm 2 In this case, since the average particle size of the currently mainstream toner is between 4 μm and 10 μm, when such a toner is used, the layer formed by the toner T coated on the rubber roller 1 will be between approximately 1 layer and 1.5 layers. Therefore, in the main measurement described later, the toner T will be more likely to be uniformly subjected to the friction force between the outer circumferential surface of the rubber roller 1 and the surface of the flat plate 104.

[0031] (Measurement (Rubbing method on toner particle surface)) Next, the toner coated on the rubber roller 1 is brought into contact with the flat plate 104 at a pressure (contact pressure) of 0.04 MPa, and the toner, specifically the surface of the toner particles, is rubbed.

[0032] FIG. 3 shows an example of a rubbing device 100 that can rub the surfaces of toner particles by bringing a flat plate 104 into contact with a rubber roller 1 with a desired pressure.

[0033] In Fig. 3, the rubbing device 100 is composed of a lower unit 102 and an upper unit 103 disposed above the lower unit 102 at a predetermined distance. The upper unit 103 is connected to the lower unit 102 via an elastic member (a compression coil spring in Fig. 3) 105 so as to be able to swing freely in the vertical direction (the direction of the arrow UD in Fig. 3). Furthermore, the upper unit 103 has a guided portion 103a that protrudes toward the lower unit 102. The lower unit 102 has a guide portion 102a that is disposed opposite the guided portion 103a. The guide portion 102a is formed to extend continuously in the swinging direction of the upper unit 103, i.e., the vertical direction (the direction of the arrow UD in Fig. 3), in order to guide the swinging of the guided portion 103a, and is configured to engage or abut with the guided portion 103a.

[0034] Therefore, the upper unit 103 has the function of being able to swing up and down. Furthermore, a load cell 106 is interposed between the lower unit 102 and the upper unit 103. The load cell 106 detects the force when the upper unit 103 swings up and down and converts the electrical signal into pressure. There are no particular limitations on the load cell 106 as long as it can detect load or force, and detection means such as a strain gauge type or a piezoelectric type can be appropriately selected depending on the type of device, etc.

[0035] 3, flat plate 104 is a plate-like body having a required length and thickness, and is attached below lower unit 102 via attachment members 107 (upper attachment member 107a and lower attachment member 107b) so that its outer surface abuts against the outer circumferential surface of rubber roller 1. In Fig. 3, flat plate 104 is made of SUS304, has a surface arithmetic mean roughness Ra of 0.15 μm or less, and a ten-point mean roughness Rz of 1.0 μm or less, a thickness of 0.08 mm, and a length (left-right length in Fig. 3) of 22.6 cm.

[0036] The contact pressure can be calculated by dividing the contact force of the flat plate 104 by the nip area between the rubber roller 1 and the flat plate 104 .

[0037] The contact pressure can be calculated by varying the contact pressure in advance and observing the flat plate 104 under a microscope. That is, it can be obtained experimentally by verifying the nip width between the rubber roller 1 and the flat plate 104 while varying the contact pressure and contact force. For example, if a nip width of 700 μm is formed between the rubber roller 1 and the flat plate 104 when the flat plate 104 is pressed against the rubber roller 1 with a contact force of 7 N, then since the length of the flat plate 104 is 22.6 cm, a pressure of 0.04 MPa is applied between the rubber roller 1 and the flat plate 104.

[0038] Under these contact conditions, the rubber roller 1 coated with the toner T is rotated in a predetermined direction (the direction of arrow F in FIG. 3) for five revolutions at 30 rpm. As a result, the outer circumferential surface of the rubber roller 1 reaches a position facing the flat plate 104, and the flat plate 104 (more specifically, its surface) comes into contact with the toner T coated on the outer circumferential surface of the rubber roller 1. As the rubber roller 1 rotates, the flat plate 104 rubs against the surface of the toner T coated on the outer circumferential surface of the rubber roller 1 at this position.

[0039] Thereafter, the contact between the rubber roller 1 and the flat plate 104 is released, and the toner T after rubbing is collected.

[0040] (Measurement of the change in the amount of antibacterial agent (number of antibacterial agent particles) before and after rubbing (rotation)) The number of antibacterial agent particles present on the surface of a toner particle can be measured by observing the surface with a scanning electron microscope (SEM).

[0041] For example, a scanning electron microscope "FE-SEM S-4800" (trade name; manufactured by Hitachi, Ltd.) is used to observe the toner at various magnifications that allow the number of toner particles and antibacterial agent particles to be counted. For example, the focus is set on the toner particle surface, and photographs of 20 random locations on the toner particle surface are taken. In some cases, the number of target antibacterial agent particles is counted in an enlarged field of view, such as by using a magnified photograph. Before rubbing (main measurement), in a surface image of the toner particles obtained by surface observation using a scanning electron microscope, the average number of antibacterial agent particles present in the surface image per toner particle is defined as X, and after rubbing, in a surface image of the toner particles obtained by surface observation using a scanning electron microscope, the average number of antibacterial agent particles present in the surface image per toner particle is defined as Y.

[0042] The above method does not reveal the state of the toner particles (external additive status) on the back side of the observation surface. However, since the state of other toner particles is the same and measurements are performed on multiple toner particles, it is thought that there is no effect.

[0043] (Evaluation of the change (ratio) in the amount of antibacterial agent (number of antibacterial agent particles) before and after rubbing (rotation)) In the present invention, when the average number of antibacterial agent particles present in a surface image of a single toner particle obtained by observing the surface with a scanning electron microscope before rubbing is defined as X, and the average number of antibacterial agent particles present in a surface image of a single toner particle obtained by observing the surface with a scanning electron microscope after rubbing is defined as Y, the ratio of Y to X (Y / X) must satisfy the following formula (1): 0.7≦Y / X≦1.0 (1)

[0044] When the relationship between the average number X of antibacterial agent particles present on the toner particle surface before rubbing (rotation) and the average number Y of antibacterial agent particles present on the toner particle surface after rubbing is 0.7≦Y / X≦1.0, the toner to which antibacterial agent particles have been externally added can remain on the media with almost no migration from the toner particle surface even under various loads (especially rubbing forces) during the electrophotographic process.

[0045] Y / X is preferably 0.8 or more and 1.0 or less. If Y / X is less than 0.7, the amount of antibacterial agent particles that migrate from the toner particle surface drops sharply, the amount of antibacterial agent (particles) on the media decreases, and sufficient antibacterial properties cannot be exhibited.

[0046] It is possible to ensure antibacterial properties by using a large amount of toner to cover the amount of antibacterial agent on the media, but this is undesirable because it would require a huge amount of toner and would lead to a significant increase in costs.

[0047] Each component constituting the toner and the method for producing the toner will be described in more detail below.

[0048] <Toner particles> The shape of the toner particles in the present invention is not particularly limited. 3 It is preferable to use toner particles having a shape with 10 or more independent recesses (pores, depressions, etc.) with a width of less than 100 nm and a depth of 20 nm or more per particle. Such toner particles further suppress migration of antibacterial agent particles, and the range of preferred particle sizes of antibacterial agent particles described below changes (becomes wider). Therefore, for example, antibacterial agent particles with a particle size of 10 nm or more and 300 nm or less can be preferably used.

[0049] Furthermore, when using such toner particles, The formation of depressions on the surface of the toner particles creates unevenness, which increases the contact area with the antibacterial agent particles and increases the overall adhesive force between the toner particles and the antibacterial agent particles. Furthermore, when depressions are intentionally created in the toner particles and antibacterial particles are carried in those depressions, the toner particles are not subjected to, or are subjected to very little, stress (especially rubbing force) during the electrophotographic process, which further suppresses the migration of antibacterial particles from the toner particle surface. Such excellent effects can be obtained.

[0050] The width of the recess is 1 μm. 3 When the particle size is 100 nm or more per particle, the effect of increasing the contact area between the toner particle surface and the antibacterial agent particles is weakened, and migration of the antibacterial agent particles tends to occur again.

[0051] Furthermore, with regard to the particle size of the antibacterial particles, if it is larger than 300 nm, the weight of the antibacterial particles themselves will be greater than the increase in contact area, and therefore migration of the antibacterial particles will tend not to be suppressed.

[0052] There is no particular limit to the number of recesses, but if the toner particle as a whole has 10 or more independent recesses each having a width of less than 100 nm and a depth of 20 nm or more, the increase in contact area and the amount of antibacterial agent particles present in the recesses will be sufficient, thereby further suppressing the migration of antibacterial agent particles from the toner particle surface.

[0053] (binder resin) The toner particles contain a binder resin. As the binder resin, the following polymers or resins can be used. The binder resin preferably contains a polyester resin, and more preferably contains an amorphous polyester.

[0054] For example, homopolymers of styrene and its substituted derivatives such as polystyrene, poly-p-chlorostyrene, and polyvinyltoluene; styrene-p-chlorostyrene copolymer, styrene-vinyltoluene copolymer, styrene-vinylnaphthalene copolymer, styrene-acrylic acid ester copolymer, styrene-methacrylic acid ester copolymer, styrene-α-chloromethyl methacrylate copolymer, styrene-acrylonitrile copolymer, styrene-vinyl methyl ether copolymer, styrene-vinyl ethyl ether copolymer, styrene-vinyl methyl ketone copolymer, and styrene-acrylonitrile-indene copolymer; polyvinyl chloride, phenolic resin, natural resin-modified phenolic resin, natural resin-modified maleic acid resin, acrylic resin, methacrylic resin, polyvinyl acetate, silicone resin, polyester resin, polyurethane resin, polyamide resin, furan resin, epoxy resin, xylene resin, polyvinyl butyral, terpene resin, coumarone-indene resin, and petroleum-based resins can be used.

[0055] Amorphous polyester is a resin having a "polyester structure" in the binder resin chain, and specific components constituting the polyester structure include divalent or higher alcohol monomer components and acid monomer components such as divalent or higher carboxylic acids, divalent or higher carboxylic acid anhydrides, and divalent or higher carboxylic acid esters.

[0056] Examples of the dihydric or higher alcohol monomer component include alkylene oxide adducts of bisphenol A such as polyoxypropylene(2.2)-2,2-bis(4-hydroxyphenyl)propane, polyoxypropylene(3.3)-2,2-bis(4-hydroxyphenyl)propane, polyoxyethylene(2.0)-2,2-bis(4-hydroxyphenyl)propane, polyoxypropylene(2.0)-polyoxyethylene(2.0)-2,2-bis(4-hydroxyphenyl)propane, and polyoxypropylene(6)-2,2-bis(4-hydroxyphenyl)propane; ethylene glycol; diethylene glycol; triethylene glycol; 1,2- Examples of suitable glycerides include propylene glycol, 1,3-propylene glycol, 1,4-cyclohexanedimethanol, dipropylene glycol, polyethylene glycol, polypropylene glycol, polytetramethylene glycol, sorbitol, 1,2,3,6-hexanetetrol, 1,4-sorbitan, pentaerythritol, dipentaerythritol, tripentaerythritol, 1,2,4-butanetriol, 1,2,5-pentanetriol, glycerin, 2-methylpropanetriol, 2-methyl-1,2,4-butanetriol, trimethylolethane, trimethylolpropane, 1,3,5-trihydroxymethylbenzene, and isosorbide.

[0057] Among these, the alcohol monomer component that is preferably used is an aromatic diol, and the alcohol monomer component that constitutes the polyester resin preferably contains the aromatic diol in a proportion of 80 mol % or more.

[0058] On the other hand, examples of acid monomer components such as divalent or higher carboxylic acids, divalent or higher carboxylic acid anhydrides, and divalent or higher carboxylic acid esters include aromatic dicarboxylic acids or anhydrides thereof such as phthalic acid, isophthalic acid, and terephthalic acid; alkyl dicarboxylic acids or anhydrides thereof such as succinic acid, adipic acid, sebacic acid, and azelaic acid; succinic acid or anhydrides thereof substituted with an alkyl or alkenyl group having from 6 to 18 carbon atoms; and unsaturated dicarboxylic acids or anhydrides thereof such as fumaric acid, maleic acid, and citraconic acid.

[0059] Among these, preferred acid monomer components are polycarboxylic acids such as terephthalic acid, succinic acid, adipic acid, fumaric acid, trimellitic acid, pyromellitic acid, benzophenonetetracarboxylic acid and anhydrides thereof.

[0060] The acid value of the polyester resin is preferably 1 mgKOH / g or more and 50 mgKOH / g or less from the viewpoint of the stability of the triboelectric charge amount.

[0061] The acid value can be adjusted to the above range by adjusting the type and amount of monomers used in the resin. Specifically, it can be controlled by adjusting the alcohol monomer component ratio / acid monomer component ratio and molecular weight during resin production. Furthermore, it can be controlled by reacting the terminal alcohol with a polyacid monomer (e.g., trimellitic acid) after ester polycondensation.

[0062] Furthermore, a crystalline polyester can also be used as the binder resin.

[0063] (coloring agent) The toner particles may contain a colorant. The colorant is not particularly limited, and for example, the following known colorants may be used alone or in combination.

[0064] Examples of black colorants include carbon black and those toned to black using a yellow colorant, a magenta colorant, and a cyan colorant.

[0065] Magenta colored pigments include the following: CI Pigment Red 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 21, 22, 23, 30, 31, 32, 37, 38, 39, 40, 41, 48:2, 48:3, 48:4, 49, 50, 51, 52, 53, 54, 55, 57:1, 58, 60, 63, 64, 68, 81:1, 83, 87, 88, 89, 90, 112, 114, 122, 123, 146, 147, 150, 163, 184, 202, 206, 207, 209, 238, 269, 282; CI Pigment Violet 19; CI Bat Red 1, 2, 10, 13, 15, 23, 29, 35.

[0066] Magenta-colored dyes include solvent dyes such as CI Solvent Red 1, 3, 8, 23, 24, 25, 27, 30, 49, 81, 82, 83, 84, 100, 109, and 121; CI Disperse Red 9; CI Solvent Violet 8, 13, 14, 21, and 27; and CI Disperse Violet 1; and basic dyes such as CI Basic Red 1, 2, 9, 12, 13, 14, 15, 17, 18, 22, 23, 24, 27, 29, 32, 34, 35, 36, 37, 38, 39, and 40; and CI Basic Violet 1, 3, 7, 10, 14, 15, 21, 25, 26, 27, and 28.

[0067] Cyan coloring pigments include CI Pigment Blue 2, 3, 15:2, 15:3, 15:4, 16, and 17; CI Vat Blue 6; and CI Acid Blue 45, and copper phthalocyanine pigments having one to five phthalimidomethyl groups substituted on the phthalocyanine skeleton.

[0068] Cyan colored dyes include CI Solvent Blue 70.

[0069] Yellow coloring pigments include the following: CI Pigment Yellow 1, 2, 3, 4, 5, 6, 7, 10, 11, 12, 13, 14, 15, 16, 17, 23, 62, 65, 73, 74, 83, 93, 94, 95, 97, 109, 110, 111, 120, 127, 128, 129, 147, 151, 154, 155, 168, 174, 175, 176, 180, 181, 185; CI Vat Yellow 1, 3, 20.

[0070] Yellow coloring dyes include CI Solvent Yellow 162.

[0071] The content of the colorant in the toner particles is preferably 3.0% by mass or more and 15.0% by mass or less.

[0072] (mold release agent) From the viewpoint of separability, the toner particles preferably contain a wax as a release agent. The wax is not particularly limited, but examples thereof include the following.

[0073] Hydrocarbon waxes such as low molecular weight polyethylene, low molecular weight polypropylene, alkylene copolymers, microcrystalline wax, paraffin wax, and Fischer-Tropsch wax; oxides of hydrocarbon waxes such as oxidized polyethylene wax or their block copolymers; waxes whose main component is fatty acid esters such as carnauba wax; partially or completely deoxidized fatty acid esters such as deoxidized carnauba wax.

[0074] Further examples include the following: saturated straight-chain fatty acids such as palmitic acid, stearic acid, and montanic acid; unsaturated fatty acids such as brassidic acid, eleostearic acid, and parinaric acid; saturated alcohols such as stearyl alcohol, aralkyl alcohols, behenyl alcohol, carnaubyl alcohol, ceryl alcohol, and melissyl alcohol; polyhydric alcohols such as sorbitol; esters of fatty acids such as palmitic acid, stearic acid, behenic acid, and montanic acid with alcohols such as stearyl alcohol, aralkyl alcohols, behenyl alcohol, carnaubyl alcohol, ceryl alcohol, and melissyl alcohol; fatty acid amides such as linoleic acid amide, oleic acid amide, and lauric acid amide; methylenebisstearic acid amide, ethylenebiscapric acid amide, ethylenebislauric acid amide, hexamethylenebis(isopropyl methyl acrylate) saturated fatty acid bisamides such as stearic acid amide; unsaturated fatty acid amides such as ethylene bisoleic acid amide, hexamethylene bisoleic acid amide, N,N'-dioleyl adipamide, and N,N'-dioleyl sebacic acid amide; aromatic bisamides such as m-xylene bisstearic acid amide and N,N'-distearyl isophthalic acid amide; fatty metal salts (commonly known as metal soaps) such as calcium stearate, calcium laurate, zinc stearate, and magnesium stearate; waxes grafted onto aliphatic hydrocarbon waxes using vinyl monomers such as styrene and acrylic acid; partial esters of fatty acids and polyhydric alcohols such as behenic acid monoglyceride; and methyl ester compounds having hydroxyl groups obtained by hydrogenating vegetable oils and fats.

[0075] Among these releasing agents, hydrocarbon waxes such as paraffin wax and Fischer-Tropsch wax, or fatty acid ester waxes such as carnauba wax are preferred from the viewpoint of improving low-temperature fixability and hot offset resistance.

[0076] The content of the release agent in the toner particles is preferably 3.0% by mass or more and 15.0% by mass or less. When the content of the release agent is in this range, it is easy to efficiently exhibit hot offset resistance.

[0077] (charge control agent) The toner particles may contain a charge control agent. There are no particular limitations on the charge control agent, and known agents can be used. In particular, charge control agents that have a high charging speed and can stably maintain a constant charge amount are preferred. The charge control agent may be added internally or externally to the toner particles.

[0078] Examples of charge control agents that control toner particles to be negatively charged include the following: Organometallic compounds and chelating compounds include monoazo metal compounds, acetylacetone metal compounds, aromatic oxycarboxylic acids, aromatic dicarboxylic acids, oxycarboxylic acids, and dicarboxylic acid-based metal compounds. Other examples include aromatic oxycarboxylic acids, aromatic mono- and polycarboxylic acids, and their metal salts, anhydrides, or esters, and phenol derivatives such as bisphenols. Further examples include urea derivatives, metal-containing salicylic acid compounds, metal-containing naphthoic acid compounds, boron compounds, quaternary ammonium salts, and calixarenes.

[0079] On the other hand, examples of charge control agents that control toner particles to a positive charge include the following: nigrosine and nigrosine modified with fatty acid metal salts; guanidine compounds; imidazole compounds; quaternary ammonium salts such as tributylbenzylammonium-1-hydroxy-4-naphthosulfonate and tetrabutylammonium tetrafluoroborate, and onium salts such as phosphonium salts that are analogs of these, and lake pigments thereof; triphenylmethane dyes and lake pigments thereof (lacquering agents include phosphotungstic acid, phosphomolybdic acid, phosphotungstomolybdic acid, tannic acid, lauric acid, gallic acid, ferricyanide, ferrocyanide, etc.); metal salts of higher fatty acids; and resin-based charge control agents.

[0080] These charge control agents can be used alone or in combination of two or more. The content of these charge control agents in the toner particles is preferably 0.01% by mass or more and 10% by mass or less.

[0081] <Antibacterial agent> The toner particles contain antibacterial particles as an external additive on their surfaces. There are no particular limitations on the antibacterial agent (composed of antibacterial particles) that can be used in the present invention, as long as it has antibacterial properties. Known inorganic and organic antibacterial agents can be used as the antibacterial agent. Inorganic antibacterial agents are particularly suitable due to their excellent heat resistance and stability. Examples of inorganic antibacterial agents that can be used include metal and metal compound antibacterial agents, and oxide photocatalyst antibacterial agents. Metals that can be used include silver, copper, and zinc. These metals can be used as simple metals and / or antibacterial metal ions, or they can be supported on other particles, particularly inorganic materials. Examples of carriers that can be used to support antibacterial metals include, but are not limited to, alumina, zeolite, silica gel, phosphate compounds, calcium carbonate, calcium silicate, and silicate glass. These can be used alone or in combination. The antibacterial agent is preferably selected from silver and its oxides.

[0082] Among these antibacterial agents, silver and / or silver oxide supported on other particles are more preferred because of their safety to the human body and their broad antibacterial spectrum.

[0083] When the antibacterial particles are composed of other particles carrying simple metals and / or antibacterial metal ions, it is preferable to carry simple metals and / or antibacterial metal ions, preferably silver and / or silver oxide, more preferably silver or silver oxide, on particles having a primary particle size of 100 nm or less.

[0084] Although there is no particular limitation on the particle size of the antibacterial particles in the present invention, a smaller particle size is preferable. As the particle size of the antibacterial particles becomes smaller, the adhesion force to the toner particle matrix increases, which further suppresses the migration of the antibacterial particles from the toner particle surface. Furthermore, by reducing the particle size, the specific surface area of ​​the antibacterial particles increases, so that antibacterial properties are exhibited with a smaller amount of antibacterial agent.

[0085] In addition, the specific toner, i.e., 1 μm 3 If the toner particles do not have 10 or more independent recesses (pores, etc.) each having a width of less than 100 nm and a depth of 20 nm or more, the particle size of the antibacterial agent particles is more preferably 100 nm or less, and even more preferably 50 nm or less.

[0086] The particle size of the antibacterial agent particles is preferably 10 nm or more. Antibacterial agent particles with a size of less than 10 nm tend to undergo secondary and tertiary aggregation due to their high cohesive force, and therefore tend to increase in particle size when externally added, causing migration of the antibacterial agent particles from the surface of the toner particles.

[0087] There are no particular restrictions on the content of the antibacterial particles, but when silver and / or silver oxide are used as the antibacterial particles, it is preferable that the content or concentration of silver or silver oxide in the toner particles be set to an appropriate level while maintaining antibacterial properties, from the perspective of image control. If the content or concentration of silver and / or silver oxide as antibacterial particles in the toner particles is high, fog tends to occur in unintended areas during development. When silver and / or silver oxide are used as the antibacterial particles, the content or concentration of the silver and / or silver oxide is preferably 50 ppm or more and 500 ppm or less in total relative to the mass of the entire toner particles.

[0088] <External additives> In order to improve the performance of the toner, the toner may further contain external additives other than the antibacterial agent.

[0089] <Method of manufacturing toner particles> The method for producing toner particles is not particularly limited, and known methods can be used. For example, methods for producing toner directly in a hydrophilic medium, such as emulsion aggregation, solution suspension, and suspension polymerization, can be used. Alternatively, a pulverization method can be used, and the toner obtained by the pulverization method can be thermally spheronized.

[0090] Specifically, toner particles can be produced by the following production methods: a kneading and pulverization method in which a binder resin is mixed with, if necessary, a colorant, a release agent, and a charge control agent, and toner particles are obtained through kneading, pulverization, and classification processes; a dissolution and suspension method in which a binder resin is dissolved or dispersed in an organic solvent together with, if necessary, a colorant, a release agent, and a charge control agent, and the mixture is granulated in an aqueous medium, and the solvent is then removed to obtain toner particles; an emulsion aggregation method in which a binder resin is finely dispersed in an aqueous medium together with fine particles of, if necessary, a colorant, a release agent, and a charge control agent, and the mixture is aggregated to a predetermined toner particle size (particle diameter), to obtain toner particles; and a suspension polymerization method in which a polymerizable monomer, a colorant, a release agent, and a charge control agent are dissolved or dispersed in an aqueous medium, and the mixture is granulated in an aqueous medium, and the polymerizable monomer is polymerized with a polymerization initiator to obtain toner particles.

[0091] Among these, it is preferable to use the emulsion aggregation method or suspension polymerization method, which can easily make the toner particles uniform in shape to a substantially spherical shape and can provide excellent uniformity in charge distribution.

[0092] The polymerizable monomer may be a vinyl polymerizable monomer.

[0093] Specifically, the following can be mentioned:

[0094] Styrene; styrene derivatives such as α-methylstyrene, β-methylstyrene, o-methylstyrene, m-methylstyrene, p-methylstyrene, and 2,4-dimethylstyrene; acrylic polymerizable monomers such as methyl acrylate, ethyl acrylate, n-propyl acrylate, isopropyl acrylate, n-butyl acrylate, isobutyl acrylate, tert-butyl acrylate, and 2-ethylhexyl acrylate; methacrylic polymerizable monomers such as methyl methacrylate, ethyl methacrylate, n-propyl methacrylate, isopropyl methacrylate, n-butyl methacrylate, isobutyl methacrylate, and tert-butyl methacrylate; methylene aliphatic monocarboxylic acid esters; vinyl esters such as vinyl acetate, vinyl propionate, vinyl butyrate, vinyl benzoate, and vinyl formate.

[0095] The toner of the present invention can be used, for example, as a toner for electrophotography. When used as a toner for electrophotography, migration of the antibacterial agent (particles) from the toner during the electrophotographic process is suppressed, so that sufficient antibacterial properties can be exhibited with a smaller amount of the antibacterial agent.

[0096] [Developer] The toner of the present invention can be used as a one-component or two-component developer, and can be used in either development method. For example, in the case of a magnetic toner containing a magnetic substance as a one-component developer, a magnet incorporated in a developing sleeve can be used to transport and charge the magnetic toner. In the case of a non-magnetic toner containing no magnetic substance, a blade or fur brush can be used to frictionally charge the toner and cause it to adhere to the developing roller.

[0097] When used as a two-component developer, the magnetic carrier to be mixed with the toner is composed of, for example, an element selected from iron, copper, zinc, nickel, cobalt, manganese, chromium, etc., either singly or in a ferrite state. The shape of the magnetic carrier used in this case can be spherical, flat, irregular, etc., and magnetic carriers with appropriately controlled surface microstructures (e.g., surface unevenness) can also be used. Resin-coated carriers whose surfaces are coated with resin can also be used suitably. The average particle size of the carrier used is preferably 10 μm to 100 μm, more preferably 20 μm to 50 μm. When preparing a two-component developer by mixing these carriers with the toner, the toner concentration in the developer is preferably about 2% to 15% by mass.

[0098] [Method for determining or manufacturing toner] According to the present invention, a method for producing a toner particle-containing toner particle dispersion includes the steps of: observing the surface of the toner using a scanning electron microscope; and measuring an average number X of antibacterial agent particles present in a surface image of a toner particle contained in the toner, the surface image being obtained; The toner is carried or coated on a rubber roller. More specifically, the toner is applied at a rate of 0.3 μL / cm 2 onto the outer circumferential surface of a rotatable rubber roller having a diameter of 10 mm. 2 and a step of supporting or coating the metal with the metal. a step of rubbing the outer peripheral surface of the rubber roller against the surface of a flat plate having a surface arithmetic mean roughness Ra of 0.15 μm or less and a ten-point mean roughness Rz of 1.0 μm or less, with a contact pressure of 0.04 MPa, by rotating the rubber roller five times at 30 rpm; a step of measuring an average number Y of antibacterial agent particles present in a surface image of toner particles contained in the toner obtained by observing the surface of the toner using a scanning electron microscope after the rubbing; a determining step of determining the antibacterial property of the toner based on the measured X and Y, more specifically, determining that the antibacterial property of the toner is high or improved when the measured X and Y satisfy the following formula (1); It is possible to provide a determination method comprising the steps of: 0.7≦Y / X≦1.0 (1)

[0099] According to the determination method having such a configuration, it is possible to determine whether the toner can impart sufficient antibacterial properties to the media with a smaller amount of antibacterial agent, and as a result, it is possible to provide a toner with improved antibacterial properties, particularly a toner in which antibacterial agent particles are present at least on the surface of the toner particles.

[0100] Furthermore, it is possible to provide a method for producing a toner that includes a step of determining the antibacterial properties of the toner by carrying out such a determination method.

[0101] [Electrophotographic Device] The toner of the present invention can be used to form a developing means (a unit having a toner). For example, a plurality of components such as the developing means, photosensitive member (a unit having a photosensitive member), primary charging means (charging unit), transfer means (transfer unit), cleaning means (cleaning unit), pre-exposure means (discharging unit), and auxiliary charging means (auxiliary charging unit) can be combined together to form a process cartridge, and this process cartridge can be configured to be detachably attached to the main body of an electrophotographic apparatus such as a copier or printer. That is, according to the present invention, an electrophotographic apparatus having a developing means using a toner can be provided.

[0102] [Configurations included in the embodiments of the present invention] The disclosure of this embodiment includes the following configuration. (Configuration 1) A toner having toner particles and an external additive, the external additive contains at least antibacterial agent particles, the antibacterial agent particles are present at least on the surface of the toner particles, The toner was applied at a concentration of 0.3 μL / cm on the outer peripheral surface of a rotatable rubber roller having a diameter of 10 mm. 2The surface of a flat plate made of SUS304, having an arithmetic mean roughness Ra of 0.15 μm or less and a ten-point mean roughness Rz of 1.0 μm or less, is brought into contact with the outer circumferential surface of the rubber roller at a contact pressure of 0.04 MPa, and the rubber roller is rotated 5 times at 30 rpm to rub the surface, and then the surface is observed using a scanning electron microscope to obtain a surface image of the toner particles, where Y is the average number of the antibacterial agent particles present in the surface image per toner particle, and X is the average number of the antibacterial agent particles present in the surface image per toner particle in the surface image of the toner particles obtained by observing the surface using a scanning electron microscope before the rubbing, The Y and the X satisfy the following formula (1): A toner characterized by: 0.7≦Y / X≦1.0 (1) (Configuration 2) The toner according to Configuration 1, wherein the external additive contains 50 ppm or more of the antibacterial agent particles. (Configuration 3) The antibacterial particles are particles with a primary particle size of 100 nm or less carrying silver and / or silver oxide, 3. The toner according to claim 1, wherein the content of the silver and / or silver oxide is 50 ppm or more and 500 ppm or less based on the mass of the entire toner. (Configuration 4) The toner particles are 1 μm 3 4. The toner according to any one of configurations 1 to 3, wherein the toner has 10 or more independent recesses each having a width of less than 100 nm and a depth of 20 nm or more per particle. (Configuration 5) The toner according to any one of Configurations 1 to 4, which is for electrophotography. (Configuration 6) A developer having a toner, The toner is the toner according to any one of claims 1 to 5. A developer characterized by: [Example]

[0103] The present invention will be described in more detail below with reference to examples and comparative examples. However, the present invention is not limited to the following examples. In the examples, "parts" means "parts by mass" unless otherwise specified.

[0104] <Preparation of Toner Particles A> Based on 100 parts by mass of styrene monomer, 16.5 parts by mass of CI Pigment Yellow 155 and 3.0 parts by mass of an aluminum compound of di-tertiary butyl salicylic acid [Bontron E88 (manufactured by Orient Chemical Industry Co., Ltd.)] were prepared. These were introduced into an attritor (manufactured by Nippon Coke and Engineering Co., Ltd.) and stirred at 200 rpm at 25°C for 180 minutes using zirconia beads (140 parts by mass) with a radius of 1.25 mm, to obtain masterbatch dispersion 1.

[0105] Separately, 450 parts by mass of 0.1M Na3PO4 aqueous solution was added to 710 parts by mass of ion-exchanged water and heated to 60°C, and then 67.7 parts by mass of 1.0M CaCl2 aqueous solution was gradually added to obtain an aqueous medium containing a calcium phosphate compound. Masterbatch dispersion liquid 1 40 parts by mass Styrene monomer 28 parts by mass n-Butyl acrylate monomer 18 parts by mass Hydrocarbon wax 9 parts by weight (Fischer-Tropsch wax, maximum endothermic peak = 78°C, Mw = 750) Polyester resin 5 parts by weight (Polycondensation polymer of terephthalic acid, isophthalic acid, propylene oxide-modified bisphenol A (2-mol adduct), and ethylene oxide-modified bisphenol A (2-mol adduct) = 30:30:30:10, acid value 11, Tg = 74°C, Mw = 11,000, Mn = 4,000) The above materials were heated to 65°C and uniformly dissolved and dispersed at 5,000 rpm using a TK Homomixer (manufactured by Tokushu Kika Kogyo Co., Ltd.) To this, 7.1 parts by mass of a 70% toluene solution of a polymerization initiator, 1,1,3,3-tetramethylbutylperoxy 2-ethylhexanoate, was dissolved to prepare a polymerizable monomer composition.

[0106] The polymerizable monomer composition was added to the aqueous medium and stirred at 10,000 rpm for 10 minutes in a TK homomixer (manufactured by Tokushu Kika Kogyo Co., Ltd.) at 65°C under a N2 atmosphere to granulate the polymerizable monomer composition. The resulting granules were then heated to 67°C while stirring with a paddle impeller. When the polymerization conversion of the polymerizable vinyl monomer reached 90%, 0.1 mol / L aqueous sodium hydroxide solution was added to obtain an aqueous dispersion medium with a pH of 9. The resulting mixture was further heated to 80°C at a rate of 40°C / h and reacted for 4 hours. After the polymerization reaction was completed, the remaining monomer from the replenishment toner particles was distilled off under reduced pressure. After cooling the aqueous dispersion medium, hydrochloric acid was added to adjust the pH to 1.4, and the mixture was stirred for 6 hours to dissolve the calcium phosphate salt. The toner particles were filtered, washed with water, and then dried at 40°C for 48 hours. The resulting dried product was subjected to classification using a multi-division classifier (elbow jet classifier) ​​manufactured by Nittetsu Mining Co., Ltd. to simultaneously remove ultrafine particles and coarse particles, thereby obtaining toner particles (yellow toner particles) A.

[0107] When the toner particles A were observed using a scanning electron microscope, no independent depressions with a width of less than 100 nm and a depth of 20 nm or more were found.

[0108] <Preparation of Toner Particles B> (Production example of polyester resin) A reactor equipped with a stirrer, thermometer, and outflow cooler was charged with 20 parts of propylene oxide-modified bisphenol A (2-mol adduct), 80 parts of propylene oxide-modified bisphenol A (3-mol adduct), 20 parts of terephthalic acid, 20 parts of isophthalic acid, and 0.50 parts of tetrabutoxytitanium, and an esterification reaction was carried out at 190°C. Subsequently, 1 part of trimellitic anhydride (TMA) was added, and the temperature was raised to 220°C while the pressure in the system was gradually reduced. A polycondensation reaction was carried out at 150 Pa to obtain a polyester resin. The acid value of the resulting polyester resin was 12 mg / KOH, the softening point was 110°C, and the glass transition temperature was 60°C. Furthermore, differential scanning calorimetry (DSC) measurement of the resulting polyester resin did not show a clear endothermic peak.

[0109] (Preparation of Polyester Resin Particle Dispersion) 200 parts polyester resin 500 parts ion-exchanged water The above materials were placed in a stainless steel container and melted by heating to 95°C in a hot bath. While thoroughly stirring at 7800 rpm using a homogenizer (IKA Ultra Turrax T50), 0.1 mol / L sodium bicarbonate was added to adjust the pH to greater than 7.0. A mixed solution of 3 parts sodium dodecylbenzenesulfonate and 297 parts ion-exchanged water was then slowly added dropwise to the resulting mixture, emulsifying and dispersing it to obtain polyester resin particle dispersion 1. The particle size distribution of this polyester resin particle dispersion 1 was measured using a particle size analyzer (Horiba, Ltd., LA-920). The number-average particle size of the polyester resin particle dispersion was 0.25 μm, and no coarse particles greater than 1.00 μm were observed.

[0110] (Preparation of Wax Particle Dispersion) 500 parts ion-exchanged water 250 parts wax (hydrocarbon wax; maximum endothermic peak temperature: 77°C) The above materials were placed in a stainless steel container and heated to 95°C in a hot bath to melt. While thoroughly stirring at 7800 rpm using a homogenizer (IKA Ultra Turrax T50), 0.1 mol / L sodium bicarbonate was added to adjust the pH to greater than 7.0. A mixed solution of 5 parts sodium dodecylbenzenesulfonate and 245 parts ion-exchanged water was then slowly added dropwise to the resulting mixture to emulsify and disperse it. The particle size distribution of the wax particles contained in this wax particle dispersion was measured using a particle size analyzer (Horiba, Ltd., LA-920). The number-average particle size of the wax particles contained was 0.35 μm, and no coarse particles exceeding 1.00 μm were observed.

[0111] (Preparation of Colorant Particle Dispersion) CI Pigment Yellow 74 100 parts Sodium dodecylbenzenesulfonate 5 parts 400 parts ion-exchanged water The above ingredients were mixed and dispersed using a sand grinder mill. The particle size distribution of the colorant particles contained in the colorant particle dispersion was measured using a particle size analyzer (LA-920, manufactured by Horiba, Ltd.), and the number average particle size of the colorant particles contained was 0.20 μm, and no coarse particles exceeding 1.00 μm were observed.

[0112] (Production Example of Toner Particles B) Polyester resin particle dispersion 500 parts Colorant particle dispersion 1 50 parts Wax particle dispersion 50 parts Sodium dodecylbenzenesulfonate 5 parts The polyester resin particle dispersion, wax particle dispersion, and sodium dodecylbenzenesulfonate were charged into a reactor (1-liter flask, baffled anchor blade) and mixed uniformly. Meanwhile, colorant particle dispersion 1 was mixed uniformly in a 500 mL beaker, and this was gradually added to the reactor while stirring to obtain a mixed dispersion. While stirring the resulting mixed dispersion, 0.5 parts of aluminum sulfate aqueous solution (solid content) was added dropwise to form aggregated particles.

[0113] After the dropwise addition was completed, the system was purged with nitrogen, and the temperature was maintained at 50°C for 1 hour, and then at 55°C for 1 hour.

[0114] The temperature was then raised to 90°C and held there for 30 minutes. The temperature was then lowered to 63°C and held there for 3 hours to form fused particles. The reaction was carried out in a nitrogen atmosphere. After the specified time had elapsed, the mixture was cooled to room temperature at a rate of 0.5°C per minute.

[0115] After cooling, the reaction product was subjected to solid-liquid separation in a 10 L pressure filter under a pressure of 0.4 MPa to obtain a toner cake. Ion-exchanged water was then added to the pressure filter until it was filled with water, and washing was performed under a pressure of 0.4 MPa. The same washing was repeated three times for a total of three washings. This toner cake was dispersed in 1 L of a 50:50 mixed solvent of methanol and water in which 0.15 parts of polyoxyethylene lauryl ether had been dissolved, to obtain a toner particle dispersion.

[0116] This toner particle dispersion was poured into a pressure filter, and 5 L of ion-exchanged water was added. After that, solid-liquid separation was carried out under a pressure of 0.4 MPa, and fluidized bed drying was carried out at 45°C to obtain toner particles (yellow toner particles) B.

[0117] When the toner particles B were observed, no independent recesses having a width of less than 100 nm and a depth of 20 nm or more were present.

[0118] <Preparation of Toner Particles C> (Preparation step of aqueous medium 1) In a reaction vessel equipped with a stirrer, a thermometer, and a reflux condenser, 650.0 parts of ion-exchanged water and 14.0 parts of sodium phosphate (Rasa Kogyo Co., Ltd., 12-hydrate) were added, and the mixture was kept at 65°C for 1.0 hour while purging with nitrogen.

[0119] Aqueous medium containing a dispersion stabilizer was prepared by adding an aqueous calcium chloride solution prepared by dissolving 9.2 parts of calcium chloride (dihydrate) in 10.0 parts of ion-exchanged water all at once while stirring at 15,000 rpm using a TK homomixer (manufactured by Tokushu Kika Kogyo Co., Ltd.) Further, 10% by mass of hydrochloric acid was added to the obtained aqueous medium to adjust the pH to 5.0, thereby obtaining aqueous medium 1.

[0120] (Preparation step of polymerizable monomer composition) Styrene: 60.0 parts CI Pigment Yellow 155: 6.5 parts The above materials were placed in an attritor (manufactured by Mitsui Miike Chemical Engineering Co., Ltd.), and further dispersed using zirconia particles with a diameter of 1.7 mm at 220 rpm for 5.0 hours to prepare a pigment dispersion. The following materials were added to the obtained pigment dispersion. Styrene: 20.0 parts n-Butyl acrylate: 20.0 parts Crosslinking agent (divinylbenzene): 0.3 parts Saturated polyester resin: 5.0 parts (Polycondensation polymer of propylene oxide-modified bisphenol A (2-mol adduct) and terephthalic acid (molar ratio 10:12), glass transition temperature Tg = 68°C, weight average molecular weight Mw = 10,000, molecular weight distribution Mw / Mn = 5.12) Fischer-Tropsch wax (melting point 78°C): 7.0 parts The obtained dispersion was kept at 65° C. and was dissolved and dispersed uniformly at 500 rpm using a TK homomixer (manufactured by Tokushu Kika Kogyo Co., Ltd.) to prepare a polymerizable monomer composition.

[0121] (granulation process) While maintaining the temperature of the aqueous medium 1 at 70°C and the rotation speed of the TK homomixer at 15,000 rpm, the polymerizable monomer composition was charged into the aqueous medium 1, and 10.0 parts of t-butyl peroxypivalate as a polymerization initiator was added. Granulation was continued for 10 minutes while maintaining the stirring speed at 15,000 rpm with the stirring device.

[0122] (Polymerization and distillation processes) After the granulation step, the agitator was replaced with a propeller agitator blade, and the mixture was stirred at 150 rpm while maintaining the temperature at 70°C for 5.0 hours to carry out polymerization. The temperature was then raised to 85°C and heated for 2.0 hours to carry out the polymerization reaction.

[0123] Thereafter, the reflux tube of the reaction vessel was replaced with a cooling tube, and the slurry was heated to 100° C. to perform distillation for 6 hours to distill off the unreacted polymerizable monomer, thereby obtaining a toner base particle dispersion liquid.

[0124] (Polymerization of organosilicon compounds) 60.0 parts of ion-exchanged water was weighed into a reaction vessel equipped with a stirrer and a thermometer, and the pH was adjusted to 4.0 using 10% by mass of hydrochloric acid. This was heated with stirring until the temperature reached 40°C. 40.0 parts of methyltriethoxysilane, an organosilicon compound, was then added and stirred for 2 hours or more to carry out hydrolysis. The end point of the hydrolysis was confirmed by visual inspection when the oil and water were no longer separated and a single layer was formed, and the mixture was cooled to obtain a hydrolyzed solution of the organosilicon compound.

[0125] The resulting toner base particle dispersion was cooled to 55°C, and 25.0 parts of the organosilicon compound hydrolyzate was added to initiate polymerization of the organosilicon compound. After 15 minutes of incubation, the pH was adjusted to 5.5 with a 3.0% aqueous solution of sodium bicarbonate. After 60 minutes of incubation at 55°C with continued stirring, the pH was adjusted to 9.5 with a 3.0% aqueous solution of sodium bicarbonate, and the mixture was further incubated for 240 minutes to obtain a toner particle dispersion.

[0126] (Washing and drying process) After the polymerization process was completed, the toner particle dispersion was cooled, and hydrochloric acid was added to the toner particle dispersion to adjust the pH to 1.5 or less, and the mixture was left stirring for 1 hour. The resulting dispersion was subjected to solid-liquid separation using a pressure filter to obtain a toner cake. This was reslurried with ion-exchanged water to make a dispersion again, and then subjected to solid-liquid separation using the aforementioned filter to obtain a toner cake.

[0127] The obtained toner cake was dried and classified in a thermostatic chamber at 40° C. for 72 hours, to obtain toner particles (yellow toner particles) C.

[0128] When this toner particle C was observed, 10 or more independent recesses each having a width of less than 100 nm and a depth of 20 nm or more were confirmed.

[0129] <Preparation of antibacterial particles> (Antibacterial agent α) As the antibacterial agent α, Atomy-Ball (UA) (manufactured by JGC Catalysts and Chemicals Co., Ltd.) was used.

[0130] This antibacterial agent is a silver-based antibacterial agent in which approximately 5% of silver oxide is supported on silica alumina particles with an average particle size of 25 nm.

[0131] The antibacterial agent is a 1 to 2% monodispersed aqueous dispersion, and was therefore powdered using a small freeze dryer (freeze drier) FD-1000 (manufactured by Tokyo Rikakikai Co., Ltd.).

[0132] (Antibacterial agent β) As the antibacterial agent β, Apacider AK (manufactured by Sangi Co., Ltd.) was used.

[0133] This antibacterial agent was used as it was, since it was a powder silver-based antibacterial agent in which approximately 1.3% to 1.6% of silver was supported on tricalcium phosphate with an average particle size of 0.3 μm.

[0134] (Antibacterial agent γ) As the antibacterial agent γ, Novalon-AG1100 (manufactured by Toagosei Co., Ltd.) was used.

[0135] This antibacterial agent was a powdered silver-based compound made of a silver zirconium compound with an average particle size of 1.0 μm, and was therefore used as is.

[0136] <Toner Production> (Preparation of Toner 1) Toner particles A 100 parts Antibacterial agent α 0.1 parts The mixture was placed in an Oster Blender (Osaka Chemical Co., Ltd.), mixed at 15,700 rpm for 1 second, and then allowed to stand for 5 seconds. This process was repeated 10 times, after which the container was removed from the blender, shaken up and down by hand, and then placed back in the blender, and the above-mentioned mixing process was repeated 10 times.

[0137] The above series of operations was repeated 10 times to prepare Toner 1.

[0138] <Preparation of Toners 2 to 27> Toners 2 to 27 were prepared in the same manner as Toner 1, except that the toner particles and antibacterial agent were changed to those shown in Table 1, respectively.

[0139] <Preparation of Toner 28 for Antibacterial Activity Evaluation> To evaluate the antibacterial properties described above, a toner containing no antibacterial agent is required.

[0140] Therefore, toner particles A were treated with hydrophobic silica fine powder (primary particle diameter: 7 nm, BET specific surface area: 130 m) obtained by treating silica fine powder with 20% by mass of dimethyl silicone oil. 2 Toner 28 was prepared in the same manner as Toner 1, except that 1.5 parts by mass of PEG-14 (1.5 parts by mass / g) was mixed in place of the antibacterial agent.

[0141] <Preparation of Toner 29 for Antibacterial Activity Evaluation> Toner 29 was produced in the same manner as in the production of Toner 28, except that Toner Particles B were used instead of Toner Particles A.

[0142] <Preparation of Toner 30 for Antibacterial Activity Evaluation> Toner 30 was produced in the same manner as in the production of toner 28, except that toner particles C were used instead of toner particles A.

[0143] (Evaluation of migration of antibacterial particles) The migration evaluation of the antimicrobial particles described above (antimicrobial particle migration evaluation) was carried out.

[0144] Toner 1 was applied to roller 1 at a rate of 0.3 μL / cm 2 using the coating device shown in FIG. 2 The toner was uniformly coated with a rubbing agent. A portion of the coated toner was sampled and designated sample x before evaluation. Using the rubbing device shown in Figure 3, a portion of the toner was sampled after rubbing at 0.04 MPa and designated sample y after evaluation. Using a scanning electron microscope (FE-SEM), the number of antibacterial agent particles was counted for each of the sampled samples x and y, and the average numbers X and Y of antibacterial agent particles per toner particle were calculated, and the change in the average number of antibacterial agent particles (Y / X) was calculated.

[0145] As a result, the average change in the number of antibacterial agent particles in Toner 1 was 0.9.

[0146] Further, for toners 2 to 27, the change in the average number of antibacterial agent particles was measured in the same manner.

[0147] These are also shown in Table 1.

[0148] [Table 1]

[0149] Example 1 (Antibacterial evaluation) Toner 1 was refilled into the yellow cartridge of Color LazerJet Pro M454dn, and a 25% yellow halftone was printed on a 100 μm thick PET film.

[0150] In this evaluation, the print was made on PET because there is no established method for evaluating antibacterial properties for prints on paper. Therefore, the antibacterial properties were evaluated by calculating the antibacterial activity value using the film method of Japanese Industrial Standards JIS Z 2801:2010.

[0151] In addition, to prepare a control required for calculating the antibacterial activity value, i.e., the surface of a product that was not antibacterial treated, Toner 28 was filled into a yellow cartridge and a 25% yellow halftone was printed on a 100 μm thick PET film.

[0152] In this evaluation, printing was performed on a 25% halftone because even if the entire surface was printed solidly (100%), the toner would pile up and it would be extremely inefficient for the antibacterial agent particles to be present on the outermost surface, which is what is essentially required.

[0153] Another reason is that with a 25% halftone, the toner is coated in a thin layer, which allows the antibacterial agent on the outermost surface to be efficiently exposed.

[0154] Furthermore, it goes without saying that a 25% halftone is preferable because the halftone density is low and the form in which antibacterial properties are expressed is low cost for imparting antibacterial properties.

[0155] The results of the antibacterial evaluation (calculation of antibacterial activity value) are shown in Table 2.

[0156] Examples 2 to 17 The toners shown in Table 2 were used to calculate the antibacterial activity value in the same manner as in Example 1, thereby evaluating the antibacterial properties.

[0157] Of the toners evaluated, toner 28 was used to prepare the surface of a product that was not antibacterial treated, which served as a control for toners 2 to 5; toner 29 was used to prepare the surface of a product that was not antibacterial treated, which served as a control for toners 10 to 14; and toner 30 was used to prepare the surface of a product that was not antibacterial treated, which served as a control for toners 19 to 25.

[0158] The results of the antibacterial evaluation (calculation of antibacterial activity value) are shown in Table 2.

[0159] Comparative Examples 1 to 5 For the comparative examples, the antibacterial activity value was calculated in the same manner as in the examples, and the antibacterial properties were evaluated.

[0160] Of the toners evaluated, toner 28 was used to prepare the surface of a product that was not antibacterial treated, which served as a control for toners 6, 7, and 9; toner 29 was used to prepare the surface of a product that was not antibacterial treated, which served as a control for toner 16; and toner 30 was used to prepare the surface of a product that was not antibacterial treated, which served as a control for toner 27.

[0161] The results of the antibacterial evaluation (calculation of antibacterial activity value) are shown in Table 2.

[0162] [Table 2]

[0163] From the results of this example and comparative example, it was found that toners with an average change in antibacterial agent particle number of less than 0.7 using the evaluation method of the present invention dramatically lost their antibacterial effect (antibacterial properties). This is because most of the antibacterial agent particles added to the toner migrate before reaching the media. The inventors consider this criticality as follows.

[0164] Toner particles are subjected to physical stress, particularly friction, at various locations during the electrophotographic process. The adhesive forces of particles include van der Waals forces, powder bridging forces, and Coulomb forces, and the strength of each force is determined by the magnitude of the force relative to the particle's own gravity.

[0165] That is, it is believed that there exists a specific threshold value for the adhesive force of particles of the antibacterial agent as an external additive.

[0166] Therefore, while the manifestation of antibacterial properties is also related to the threshold amount of antibacterial agent particles present on the media surface, the evaluation method of the present invention can be said to clarify each threshold and reflect it in the electrophotographic process.

[0167] From Example 17 and Comparative Example 1, it became clear that when the toner particles have recesses, the migration of the external additive, i.e., the antibacterial agent particles, is suppressed, and the range of applicability of the antibacterial agent is expanded.

[0168] In addition, in Examples 5, 10, and 15, the concentration of silver or silver oxide used as the antibacterial agent in the toner particles was high, and although fogging occurred in unintended areas during development, the antibacterial properties were good.

[0169] Therefore, when silver and / or silver oxide is used as an antibacterial agent, it was found that an appropriate concentration of silver and / or silver oxide in the toner is preferable from the viewpoint of image control while maintaining antibacterial properties. [Explanation of symbols]

[0170] 1....Rubber roller, 11: Core metal, 12: Support portion, 13: Rubber layer (conductive silicone rubber layer), 100: Rubbing device, 102: Lower unit, 102a: Guide portion, 103: Upper unit, 103a: Guided portion, 104: Flat plate, 105: Elastic member, 106: Load cell, 107: Mounting member, 107a: Upper mounting member, 107b: Lower mounting member, 200: Coating device, 202: Toner supply roller, 203: Regulating member, 203L: Toner intake portion, L1: Axial length of core metal, L2: Cut length of rubber layer, L3: Core metal diameter (diameter of core metal), L4: Thickness of rubber layer (conductive silicone rubber layer), 102: Lower unit, 103: Upper unit, T: Toner

Claims

1. A toner having toner particles and an external additive, the external additive contains at least antibacterial agent particles, the antibacterial agent particles are present at least on the surface of the toner particles, The toner was applied at a concentration of 0.3 μL / cm onto the outer circumferential surface of a rotatable rubber roller having a diameter of 10 mm. 2 a surface of a flat plate made of SUS304, having an arithmetic mean roughness Ra of 0.15 μm or less and a ten-point mean roughness Rz of 1.0 μm or less, being brought into contact with the outer peripheral surface of the rubber roller at a contact pressure of 0.04 MPa, and the rubber roller being rotated 5 times at 30 rpm to rub the surface, and then observing the surface with a scanning electron microscope, the surface image of the toner particles is obtained, and the average number of the antibacterial agent particles present in the surface image per toner particle is defined as Y; and the average number of the antibacterial agent particles present in the surface image per toner particle is defined as X in the surface image of the toner particles obtained by observing the surface with a scanning electron microscope before the rubbing, The Y and the X satisfy the following formula (1): A toner characterized by: 0.7≦Y / X≦1.0 (1)

2. 2. The toner according to claim 1, wherein the external additive contains 50 ppm or more of the antibacterial agent particles.

3. the antibacterial particles are particles with a primary particle size of 100 nm or less carrying silver and / or silver oxide, 3. The toner according to claim 1, wherein the content of the silver and / or silver oxide is 50 ppm or more and 500 ppm or less based on the mass of the entire toner.

4. The toner particles are 1 μm 3 3. The toner according to claim 1, wherein the toner has 10 or more independent recesses each having a width of less than 100 nm and a depth of 20 nm or more per particle.

5. 3. The toner according to claim 1, which is for electrophotography.

6. a developer having a toner, The toner is the toner according to claim 1 or 2. A developer characterized by:

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