Toner and method for producing toner

Abstract

The present invention relates to a toner and a method for producing a toner. A toner including toner particles, wherein the toner particles contain a binder resin, the binder resin contains a resin A and a resin B, the toner particles include projections on surfaces thereof, the projections each contain the resin B, a shape factor SF-2 of the toner observed under SEM is 105 to 120, and when the toner is observed under SEM, a surface unevenness index of the toner calculated by the following formula (1) is 0.010 to 0.050: Surface unevenness index = (area of a region enclosed by a convex hull of the toner - projected area of the toner) / projected area of the toner (1).

Description

TECHNICAL FIELD

[0001] The present disclosure relates to toner for forming a toner image by developing an electrostatic latent image formed by a method such as electrophotography, electrostatic recording, and toner jet recording, and a manufacturing method of the toner. BACKGROUND

[0002] With the continuous development of equipment, electrophotographic technology used in copiers, printers, and facsimile receivers, etc. receives an increasing demand from users every year. In terms of recent trends, as the market expands, the range of use environments increases, and there is a strong demand for stable image quality that is not dependent on the environment. There is also a strong demand for designs that are compact but also capable of long-term printing.

[0003] To meet these requirements, electrophotography must (1) not undergo changes in developing performance (high durability) and (2) transfer the latent image to the recording medium without disturbing the latent image (high transferability). This means that the toner must have high durability and high transferability, and many improvements are aimed at addressing these issues.

[0004] To obtain high transferability, the adhesion between the toner and the transfer member is controlled by controlling the shape of the toner particles. For example, Japanese Patent Application Publication Nos. 2001-013732, 2011-197160, and 2013-064965 disclose toners in which the shape factor SF-2 of the toner particles is controlled. SUMMARY

[0005] In Japanese Patent Application Publication No. 2001-013732, because the toner particles are prepared by a conventional suspension polymerization method, toner close to a spherical shape is obtained. Such toner tends to be excessively charged and the charge amount tends to excessively increase in a low-temperature, low-humidity environment because the toner particles easily roll within the developing device.

[0006] As a result, during the latter half of long-term continuous use, the adhesion between the toner and the toner carrying member that supplies the toner increases, and a large amount of un-developed toner remains on the carrying member. When new toner is supplied to the carrying member in this state, it becomes difficult to regulate the toner on the carrying member, as a result, image fogging and contamination of the member can occur.

[0007] In Japanese Patent Application Publication No. 2011-197160 and 2013-064965, because the powdered toner is mechanically spheroidized or particles of a certain size are aggregated to obtain toner particles, the toner particles include a wide range of shapes from a circular shape to a shape having an extremely uneven surface. This can cause variation in fine line reproducibility. When such toner particles having a wide range of shapes are mixed, because the fluidity differs depending on the toner shape, the charge amount of toner having high fluidity is likely to increase; whereas the charge amount of toner having low fluidity is unlikely to increase. As a result, the toner tends to have a wide charge amount distribution, and as a result, image fogging and member contamination can occur.

[0008] Thus, the toners of Japanese Patent Application Publication No. 2001-013732, 2011-197160, and 2013-064965 all have room for improvement. Therefore, the present disclosure provides a toner that can obtain good fine line reproducibility regardless of the use environment even during long-term printing, so that image fogging and member contamination are reduced to obtain stable high-quality images, as well as a manufacturing method of the toner.

[0009] The present disclosure is a toner including toner particles, wherein

[0010] The toner particles contain a binder resin,

[0011] The binder resin contains a resin A and a resin B,

[0012] The toner particles include protrusions on their surfaces,

[0013] The protrusions each contain the resin B,

[0014] A shape factor SF-2 of the toner observed under a scanning electron microscope is 105 to 120, and

[0015] When the toner is observed under a scanning electron microscope, a surface unevenness index of the toner calculated by the following formula (1) is 0.010 to 0.050:

[0016] Surface unevenness index = (area of a region enclosed by a convex hull of the toner - projected area of the toner) / projected area of the toner (1).

[0017] The present disclosure is a manufacturing method of a toner including toner particles, wherein

[0018] The toner particles contain a binder resin,

[0019] The binder resin contains a resin A and a resin B,

[0020] The toner particles include protrusions on their surfaces,

[0021] The protrusions each contain resin B,

[0022] The shape factor SF-2 of the toner observed under a scanning electron microscope is 105 to 120, and

[0023] When the toner is observed under a scanning electron microscope, the surface unevenness index of the toner calculated from the following formula (1) is 0.010 to 0.050,

[0024] The manufacturing method includes:

[0025] Step (I) of forming particles of a polymerizable monomer composition containing resin B and a polymerizable monomer used for forming resin A in an aqueous medium,

[0026] Step (II) of polymerizing the polymerizable monomer contained in the particles of the polymerizable monomer composition in the aqueous medium to form resin particles, and

[0027] Step (III) of keeping the resin particles at a temperature above the glass transition temperature of resin B in an aqueous medium having a pH higher than the acid dissociation constant pKa of resin B:

[0028] Surface unevenness index = (area of a region enclosed by a convex hull of the toner - projected area of the toner) / projected area of the toner (1).

[0029] According to the present disclosure, it is possible to provide a toner in which good fine line reproducibility can be obtained regardless of the use environment even during long-term printing, so that image fogging and contamination of the members can be reduced to obtain stable high-quality images, and a manufacturing method of the toner.

[0030] Further features of the present application will become apparent from the following description of exemplary embodiments with reference to the drawings. BRIEF DESCRIPTION OF DRAWINGS

[0031] Figure 1 The condition of the surface of the toner particles is shown. DETAILED DESCRIPTION

[0032] Unless otherwise stated, expressions of numerical ranges in this specification such as "from XX to YY" or "between XX and YY" indicate a numerical range including the values of the upper and lower limits of the range. When a numerical range is described in stages, the upper limit and the lower limit of each numerical range can be arbitrarily combined.

[0033] (meth)acrylic acid means acrylic acid, methacrylic acid, or both acrylic acid and methacrylic acid. Similarly, (meth)acrylate means acrylate, methacrylate, or both acrylate and methacrylate.

[0034] The reference numerals in the drawings are defined as follows.

[0035] 1: Resin B, 2: Resin A

[0036] A "monomer unit" is a reaction form of a monomer substance in a polymer. For example, one carbon-carbon bonding portion in a main chain in a polymer obtained by polymerizing a vinyl-based monomer can be referred to as one unit. The vinyl-based monomer can be represented by the following formula (Z).

[0037]

[0038] In formula (Z), R Z1 represents a hydrogen atom or an alkyl group (preferably a C 1-3 alkyl group, or more preferably a methyl group), and R Z2 represents an arbitrary substituent.

[0039] The embodiments of the present disclosure are described in detail below, but the present disclosure is not limited thereto.

[0040] The toner is a toner including toner particles, in which

[0041] The toner particles contain a binder resin,

[0042] The binder resin contains a resin A and a resin B,

[0043] The toner particles include protrusions on their surfaces,

[0044] The protrusions each contain the resin B,

[0045] A shape factor SF-2 of the toner observed under a scanning electron microscope is 105 to 120, and

[0046] When the toner is observed under a scanning electron microscope, a surface unevenness index of the toner calculated by the following formula (1) is 0.010 to 0.050:

[0047] Surface unevenness index = (area of a region surrounded by a convex hull of the toner - projected area of the toner) / projected area of the toner (1).

[0048] As a result of earnest studies, the present inventors have found that, in the case of the above-described configuration, a toner having excellent transferability and optimal charge amount can be obtained. Using the toner, image fogging and member contamination can be reduced and stable high-quality images having good fine line reproducibility regardless of the use environment even during long-term printing can be obtained. The present inventors believe that these effects are obtained for the following reasons.

[0049] To achieve excellent fine line reproducibility, the transfer efficiency must be improved, and toner having few contact points is preferred. To this end, the shape factor SF-2 of the toner, as observed by scanning electron microscope, is 105 to 120. This shape factor SF-2 is preferably 107 to 118, or more preferably 110 to 116.

[0050] If this shape factor SF-2 is less than 105, image fogging is likely to occur because the charge amount tends to be excessively high. On the other hand, if the shape factor SF-2 exceeds 120, fine line reproducibility tends to decrease.

[0051] The shape factor SF-2 is a shape factor obtained by the following formula.

[0052] (Formula) SF-2 = (projected perimeter of toner) 2 / (projected area of toner) / 4π x 100

[0053] That is, the shape factor SF-2 is the ratio of the projected area of a spherical particle having the same perimeter as the toner to the projected area of the toner, expressed as a percentage.

[0054] On the other hand, to optimize the charge amount of the toner, it is necessary to obtain a narrow charge amount distribution without excessively raising the charge amount. Because the toner fluidity needs to be reduced to an appropriate degree to prevent the charge amount from being excessively high, the circularity of the toner must be reduced to an appropriate degree. Furthermore, to impart a narrow charge amount distribution to the toner, it is important that each particle of the toner 1 has uniform fluidity, or in other words, the toner shape is uniform.

[0055] Even in toners having the same shape factor SF-2, the surface shape of the particles can differ. That is, in toners in which the surface is extremely uneven and toners in which many small particles or the like are attached, the value of the shape factor SF-2 can be the same. In such cases, because the toner shape is not uniform, toner that rolls more easily is likely to obtain a higher charge amount, and toner that rolls less easily is likely to obtain a lower charge amount. As a result, the charge amount distribution of the toner is likely to be wide. If the charge amount distribution is excessively wide in this way, image fogging and contamination of the components can occur.

[0056] To eliminate this variation in toner shape, it is necessary to consider both the surface unevenness index represented by the following formula (1) and the shape factor SF-2.

[0057] Surface unevenness index = (area of region enclosed by convex hull of toner - projected area of toner) / projected area of toner (1)

[0058] The following describes a specific analysis method, but unlike the shape factor SF-2, this surface unevenness index numerically indicates the degree of unevenness of the toner surface. This means that even in toners having the same shape factor SF-2, the surface unevenness index can be used to distinguish whether the toner surface has a plurality of small unevennesses, or has only very few pits, or whether a plurality of fine particles are attached to the surface thereof.

[0059] In the case of these disclosed toners, since the toner surface has a plurality of small unevennesses on the surface thereof, image fogging associated with a wide distribution of toner charge amounts is improved while maintaining fine line reproducibility. That is, the surface unevenness index of the toner observed under a scanning electron microscope calculated by the above formula (1) is 0.010 to 0.050.

[0060] If the surface unevenness index is less than 0.010, this means that the toner exhibits no sufficient unevenness, resulting in overcharging of the toner. This increases the possibility of image fogging during long-term continuous use. On the other hand, if the surface unevenness index exceeds 0.050, this implies that the toner surface is extremely pitted or fine particles or the like are attached thereto, meaning that fine line reproducibility is likely to decrease, and also meaning that the toner is likely to have a wide distribution of charge amounts. As a result, image fogging and contamination of members are likely to occur. The surface unevenness index is preferably 0.015 to 0.045, or more preferably 0.024 to 0.040.

[0061] From the viewpoint of further improving these effects, the standard deviation of the surface unevenness index of the toner is preferably 0.010 or less, or more preferably 0.005 or less.

[0062] In order to further improve these effects, the shape factor SF-1 of the toner observed under a scanning electron microscope is preferably 105 or more. In order to improve these effects while mitigating paper fogging associated with reverse fogging in a high-temperature high-humidity environment and reducing melt adhesion to a developer blade, the shape factor SF-1 is preferably 120 or less, or more preferably 112 or less.

[0063] The shape factor SF-1 is obtained by the following formula.

[0064] (Formula) SF-1 = (projected maximum length of toner) 2 / (projected area of toner) x (π / 4) x 100

[0065] The toner of the present application is a toner having toner particles including a binder resin, wherein the binder resin includes a resin A and a resin B, the toner particles include projections on their surfaces, and the projections each include the resin B. The resin B can form the projections on the surfaces of the toner particles. In order to obtain the shape factor SF-2 and the numerical range of the surface unevenness index calculated from the formula (1), it is sufficient that the binder resin forming the toner particles includes the resin A and the resin B, the projections are formed on the surfaces of the toner particles and the resin B is included in the projections. Alternatively, the resin B can form the projections on the surfaces of the toner particles. Figure 1 The condition of the surface of the toner particles is shown. Figure 1 1 indicates the resin B, and 2 indicates the resin A.

[0066] For the easiness of production, it is preferable that the resin A includes a styrene (meth) acrylic resin and the resin B includes a polyester resin. That is, it is preferable that the projections on the surfaces of the toner particles include the polyester resin, and the recesses other than the projections on the surfaces of the toner particles include the styrene (meth) acrylic resin.

[0067] Further, the content of the polyester resin with respect to 100.0 parts by mass of the polymerizable monomers used for forming the resin A, or the content of the polyester resin with respect to 100.0 parts by mass of the resin A is preferably 3.0 parts by mass to 15.0 parts by mass because this makes many projections and recesses to be formed, and more preferably 3.0 parts by mass to 10.0 parts by mass so that some projections and recesses can be uniformly formed.

[0068] It is preferable that the toner particles include a wax, and in a cross section of the toner observed under a transmission electron microscope, assuming that As is the percentage of the area occupied by the wax in a region defined by a line drawn from the profile of the toner and 1.0 μm away from the profile in the direction along the inside of the toner, and Ac is the percentage of the area occupied by the wax in the inside region inward from the line drawn 1.0 μm away from the profile in the direction along the inside of the toner, these As and Ac preferably satisfy the following formula (2), and more preferably satisfy the following formula (2)'. The percentage of the area occupied by the wax can be controlled within a desired range by appropriately adjusting the production conditions of the toner as described below.

[0069] 50.0 ≥ [As / (Ac+As)] x 100 ≥ 3.0 (2)

[0070] 20.0 ≥ [As / (Ac+As)] x 100 ≥ 5.0 (2)'

[0071] If [As / (Ac+As)] x 100 is within the above range, it is possible to maintain the fixing property while controlling the contamination of the member by the wax and the toner melt adhesion.

[0072] The following describes a method for producing a toner, but the production method is not limited to these. The method for producing a toner of the present disclosure is a method for producing a toner including toner particles, in which

[0073] The toner particles include a binder resin,

[0074] The binder resin includes a resin A and a resin B,

[0075] The toner particles include protrusions on their surfaces,

[0076] The protrusions each include the resin B,

[0077] A shape factor SF-2 of the toner observed under a scanning electron microscope is 105 to 120, and

[0078] When the toner is observed under a scanning electron microscope, a surface relief index of the toner calculated by the following formula (1) is 0.010 to 0.050,

[0079] The method for producing includes:

[0080] Step (I), forming particles of a polymerizable monomer composition including the resin B and a polymerizable monomer for forming the resin A in an aqueous medium,

[0081] Step (II), polymerizing the polymerizable monomer included in the particles of the polymerizable monomer composition in the aqueous medium to form resin particles, and

[0082] Step (III), keeping the resin particles at a temperature above a glass transition temperature of the resin B in an aqueous medium having a pH higher than an acid dissociation constant pKa of the resin B:

[0083] The surface relief index = (area of a region enclosed by a convex hull of the toner - projected area of the toner) / projected area of the toner (1).

[0084] When the suspension polymerization is performed, the orientation of the resin B toward the interface of the toner particles in the aqueous medium is very different below and above the acid dissociation constant pKa of the resin B. That is, when the step related to the suspension polymerization is performed in an aqueous medium having a pH higher than the acid dissociation constant pKa of the resin B, the resin B tends to move to the interface.

[0085] Therefore, in order to make the resin B preferentially located on the surface of the toner particles, the resin particles obtained by polymerization can be kept in an aqueous medium having a pH higher than the acid dissociation constant pKa of the resin B. Further, in terms of the aqueous medium pH and the acid dissociation constant pKa of the resin B, preferably, the value of (aqueous medium pH) - (resin B acid dissociation constant pKa) is preferably 1.3 to 5.0, or more preferably 3.5 to 4.5.

[0086] Further, because the resin B is a high molecule, its molecular movement in the toner particles is slow. Therefore, in an aqueous medium whose pH is higher than the acid dissociation constant pKa of the resin B, the temperature is kept at or above the glass transition temperature (Tg) of the resin B. Thereby, the resin B can be actively caused to preferentially locate on the toner particle surface. As a result, when the toner particles include a protruding portion on their surfaces, the resin B can be contained in the protruding portion. Further, the resin B forms a protruding portion on the surface of the toner particles. The keeping temperature is preferably 10°C or more higher than the glass transition temperature (Tg) of the resin B, or more preferably 15°C or more higher than the glass transition temperature (Tg) of the resin B. The upper limit of the keeping temperature is not particularly limited, but it can be about 30°C or less higher than the glass transition temperature (Tg) of the resin B.

[0087] In order to partially and actively cause the resin B to preferentially locate on the surface, the keeping time is preferably 30 minutes to 6 hours, or more preferably 1 hour to 5 hours. The value of the surface unevenness index can be increased by extending the keeping time. In the step before the keeping step (III), or in other words, in the step (I) and / or the step (II), the pH of the aqueous medium is preferably less than the acid dissociation constant pKa of the resin B to cause the resin B to preferentially locate on the toner particle surface to an appropriate degree.

[0088] For ease of manufacture, for example, the resin B used for being contained in a protruding portion on the toner particle surface or for forming a protruding portion on the toner particle surface preferably contains a polyester resin. When suspension polymerization is performed as described above, the orientation toward the interface of the toner particles in the aqueous medium is very different below and above the acid dissociation constant pKa of the polyester resin because the polyester resin has a carboxyl group. That is, when kept at a temperature above the glass transition temperature of the polyester resin in an aqueous medium whose pH is higher than the acid dissociation constant pKa of the polyester resin, the polyester moves toward the interface.

[0089] Thereby, by setting the pH of the aqueous medium in the step (III) to be higher than the acid dissociation constant pKa of the polyester resin, the polyester resin can be caused to preferentially locate on the toner particle surface. Further, because the polyester resin is a high molecule, its molecular movement in the toner particles is slow. Thereby, the polyester resin can be caused to preferentially locate on the toner particle surface by keeping the temperature at or above the glass transition temperature (Tg) of the polyester resin. As a result, a protruding portion of the polyester resin on the toner particle surface can be formed.

[0090] Specifically, when a polyester resin having an acid dissociation constant pKa of less than 6.5 is used as the resin B, the pH of the aqueous medium can be set to 6.5 to 10.0 and the temperature can be maintained at the glass transition temperature (Tg) of the polyester resin or higher in the step (III). The holding time is preferably 30 minutes to 6 hours or more preferably 1 hour to 5 hours to partially and actively cause the polyester resin to preferentially locate. The pH of the aqueous medium in the step before this holding step (III), or in other words, the step (I) and / or the step (II) is preferably less than the acid dissociation constant pKa of the polyester resin, so that the polyester resin is appropriately exposed on the surface.

[0091] The acid value of the resin B is preferably 10 mgKOH / g or more, or more preferably 14 mgKOH / g or more. The acid value is also preferably 20 mgKOH / g or less. If the acid value of the resin B is 10 mgKOH / g or more, the number of acid dissociation portions increases, so that it is easier to cause the resin B to preferentially locate on the surface of the toner particles. For the suppression of fogging of an image under a high-temperature high-humidity environment (HH), an acid value of 20 mgKOH / g or less is preferred.

[0092] The resin A preferably contains a vinyl-based resin, and more preferably contains a styrene (meth)acrylic-based resin. It is preferred that the resin A contains a styrene (meth)acrylic-based resin while the resin B contains a polyester resin, and more preferably the resin A is a styrene (meth)acrylic-based resin while the resin B is a polyester resin.

[0093] The content of the polyester resin with respect to 100.0 parts by mass of the polymerizable monomers used for forming the resin A, or the content of the polyester resin with respect to 100.0 parts by mass of the resin A is preferably 3.0 parts by mass to 15.0 parts by mass because this allows many protrusions and depressions to be formed, and more preferably 3.0 parts by mass to 10.0 parts by mass so that many protrusions and depressions can be uniformly formed.

[0094] The vinyl-based resin is a resin obtained by radical polymerization of a monomer having a vinyl group (hereinafter, also simply referred to as "vinyl-based monomer"). The vinyl-based resin can be a homopolymer obtained by polymerization of one vinyl-based monomer, or a copolymer obtained by polymerization of two or more vinyl-based monomers.

[0095] Examples of the vinyl-based resin include homopolymers of monomers having a styrene skeleton such as styrene, p-chlorostyrene, and a-methylstyrene, monomers having a (meth)acrylate skeleton such as methyl acrylate, ethyl acrylate, n-propyl acrylate, n-butyl acrylate, lauryl acrylate, 2-ethylhexyl acrylate, methyl methacrylate, ethyl methacrylate, n-propyl methacrylate, lauryl methacrylate, and 2-ethylhexyl methacrylate, monomers having an ethylenically unsaturated nitrile skeleton such as acrylonitrile and methacrylonitrile, monomers having a vinyl ether skeleton such as vinyl methyl ether and vinyl isobutyl ether, monomers having a vinyl ketone skeleton such as vinyl methyl ketone, vinyl ethyl ketone, and vinyl isopropyl ketone, and monomers having an olefin skeleton such as ethylene, propylene, and butadiene, and copolymers of two or more of these monomers.

[0096] The styrene (meth)acrylic resin is preferably a resin obtained by copolymerizing a monomer having a styrene skeleton and a monomer having a (meth)acrylate skeleton. The styrene (meth)acrylic resin is preferably a copolymer obtained by copolymerizing at least a monomer having a styrene skeleton and a monomer having a (meth)acryloyl group. The meaning of the above-mentioned "(meth)acrylic" includes both of acrylic acid and methacrylic acid. Similarly, the meaning of the above-mentioned "(meth)acryloyl" includes both of acryloyl group and methacryloyl group.

[0097] Examples of the monomer having a styrene skeleton (hereinafter, also referred to as "styrene-based monomer") include styrene, alkyl-substituted styrenes such as a-methylstyrene, 2-methylstyrene, 3-methylstyrene, 4-methylstyrene, 2-ethylstyrene, 3-ethylstyrene, and 4-ethylstyrene, halogen-substituted styrenes such as 2-chlorostyrene, 3-chlorostyrene, and 4-chlorostyrene, and vinyl naphthalene. One kind of styrene-based monomer alone or a combination of two or more kinds thereof can be used. Among them, styrene is preferable as the styrene-based monomer in terms of easiness of reaction, easiness of control of reaction, and availability.

[0098] Examples of the monomer having a (meth)acryloyl group (hereinafter, also referred to as "(meth)acrylic monomer") include (meth)acrylic acid and (meth)acrylate. Examples of the (meth)acrylate include alkyl (meth)acrylates such as n-methyl (meth)acrylate, n-ethyl (meth)acrylate, n-propyl (meth)acrylate, n-butyl (meth)acrylate, n-pentyl (meth)acrylate, n-hexyl acrylate, n-heptyl (meth)acrylate, n-octyl (meth)acrylate, n-decyl (meth)acrylate, n-dodecyl (meth)acrylate, n-lauryl (meth)acrylate, myristyl (meth)acrylate, n-hexadecyl (meth)acrylate, n-octadecyl (meth)acrylate, isopropyl (meth)acrylate, isobutyl (meth)acrylate, t-butyl (meth)acrylate, isoamyl (meth)acrylate, amyl (meth)acrylate, neopentyl (meth)acrylate, isohexyl (meth)acrylate, isoheptyl (meth)acrylate, isooctyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, cyclohexyl (meth)acrylate, and t-butylcyclohexyl (meth)acrylate, aryl (meth)acrylates such as phenyl (meth)acrylate, biphenyl (meth)acrylate, biphenylyl ethyl (meth)acrylate, t-butylphenyl (meth)acrylate, and triphenyl (meth)acrylate, and dimethylaminoethyl (meth)acrylate, diethylaminoethyl (meth)acrylate, methoxyethyl (meth)acrylate, 2-hydroxyethyl (meth)acrylate, β-carboxyethyl (meth)acrylate, and (meth)acrylamide, and the like. One kind of (meth)acrylic monomer can be used alone or two or more kinds thereof can be used in combination.

[0099] The following polymerizable monomer is preferably a copolymer of a monomer having a styrene skeleton (styrene-based monomer) and a monomer having a (meth)acrylate skeleton ((meth)acrylic monomer), so that the polyester resin is partially present on the surface of the toner particle.

[0100] The copolymerization ratio of the styrene-based monomer and the (meth)acrylic monomer (styrene-based monomer / (meth)acrylic monomer based on mass) is, for example, 85 / 15 to 70 / 30.

[0101] As the polyester resin, a non-crystalline polyester resin is preferable. The non-crystalline polyester resin can also impart heat-resistant storability. Whether or not the resin is non-crystalline can be determined by whether or not the resin has a melting point using a DSC measuring unit.

[0102] The polyester resin is preferably a polycondensate of a polyol and a polycarboxylic acid. Examples of the polyol include ethylene glycol, propylene glycol, 1,3-butanediol, 1,4-butanediol, 2,3-butanediol, diethylene glycol, triethylene glycol, 1,5-pentanediol, 1,6-hexanediol, neopentyl glycol, 2-ethyl-1,3-hexanediol, cyclohexanedimethanol, butyleneglycol, octyleneglycol, cyclohexenyl dimethanol, isosorbide, hydrogenated bisphenol A, bisphenol A ethylene oxide adduct, and bisphenol A propylene oxide adduct.

[0103] Examples of the polycarboxylic acid include phthalic acids such as phthalic acid, terephthalic acid, isophthalic acid, and anhydrous phthalic acid; and acid anhydrides; and alkyl dicarboxylic acids such as succinic acid, adipic acid, sebacic acid, and azelaic acid, and acid anhydrides thereof.

[0104] The content of the resin A in the binder resin is preferably 80 to 98 mass%, or more preferably 90 to 95 mass%. The content of the resin B in the binder resin is preferably 2 to 20 mass%, or more preferably 4 to 10 mass%. The content ratio of the resin A to the resin B (based on mass, resin A / resin B) is preferably 5 to 50, or more preferably 10 to 30.

[0105] Hereinafter, the production method of the toner is described in more detail, but the production method is not limited thereto. The production method of the toner includes:

[0106] Step (I) in which particles of a polymerizable monomer composition containing the resin B and a polymerizable monomer for forming the resin A are formed in an aqueous medium,

[0107] Step (II) in which the polymerizable monomer contained in the particles of the polymerizable monomer composition is polymerized in the aqueous medium to form resin particles, and

[0108] Step (III) in which the resulting resin particles are kept at a temperature above the glass transition temperature of the resin B in the aqueous medium having a pH higher than the acid dissociation constant pKa of the resin B.

[0109] In Step (I), the polymerizable monomer composition can contain the resin B and a polymerizable monomer for forming the resin A, and, as needed, additives such as a colorant, a wax, a polymerization initiator, a charge control agent, a chain transfer agent, a polymerization inhibitor, and a crosslinking agent.

[0110] The resulting polymerizable monomer composition is dispersed in the aqueous medium to form particles of the polymerizable monomer composition containing the resin B and a polymerizable monomer for forming the resin A.

[0111] The aqueous medium can contain a poorly soluble inorganic fine particle as a dispersant.

[0112] The water-based medium containing the fine particles of the poorly water-soluble inorganic substance can be configured to contain the fine particles of the poorly water-soluble inorganic substance and a water-based medium containing water. The water-based medium can contain, in addition to the fine particles of the poorly water-soluble inorganic substance, counter ions generated at the time of production of the fine particles of the poorly water-soluble inorganic substance, and an acid (such as hydrochloric acid or sulfuric acid) or a base (such as sodium hydroxide or sodium carbonate) for adjusting the pH, and the like.

[0113] The water used for preparing the water-based medium can be, for example, deionized water. The water-based medium is preferably prepared using at least 100 parts by mass or more of water relative to 100 parts by mass of the polymerizable monomer. If the amount of water used is 100 parts by mass or more, the oil droplets (particles of the polymerizable monomer composition) can be easily formed without causing oil-water inversion.

[0114] The fine particles of the poorly water-soluble inorganic substance function as a dispersion stabilizer for the particles of the polymerizable monomer composition in the water-based medium. The fine particles of the poorly water-soluble inorganic substance can be, for example, particles having an extremely low solubility in water (measurement temperature: 60°C) in a specific pH range (such as 4.0 to 10.0) and a number average particle diameter of 1.0 μm or less.

[0115] As the dispersion stabilizer, inorganic and organic dispersion stabilizers are well known, but the inorganic dispersion stabilizer is preferable. It can also be combined with an organic dispersion stabilizer (such as a surfactant).

[0116] Examples of the fine particles of the poorly water-soluble inorganic substance include fine particles of calcium phosphate, magnesium phosphate, aluminum phosphate, zinc phosphate, magnesium carbonate, calcium carbonate, calcium hydroxide, magnesium hydroxide, aluminum hydroxide, calcium metasilicate, calcium sulfate, barium sulfate, bentonite, silicon dioxide, and aluminum oxide, and the like. Among them, calcium phosphate can be used because the particle diameter is easily controlled. One fine particle of the poorly water-soluble inorganic substance can be used or a combination of a plurality of kinds can be used.

[0117] When preparing an aqueous solution containing the fine particles of the poorly water-soluble inorganic substance, a commercially available dispersion stabilizer can be used as it is and dispersed in water as the fine particles of the poorly water-soluble inorganic substance. However, in order to obtain the fine particles of the poorly water-soluble inorganic substance having a fine and uniform particle diameter, the fine particles of the poorly water-soluble inorganic substance can also be produced in water under high-speed stirring.

[0118] For example, when using the fine particles of the inorganic substance of the poorly water-soluble calcium phosphate, it can be prepared as follows. An aqueous sodium phosphate solution and an aqueous calcium chloride solution are mixed under high-speed stirring in a low temperature range of 60°C or lower to form fine particles of calcium phosphate in water, and the fine particles of the poorly water-soluble inorganic substance are obtained.

[0119] Then, the polymerizable monomer composition is dispersed in an aqueous medium containing the poorly soluble inorganic fine particles, and the particles of the polymerizable monomer composition are granulated. Thereby, a dispersion of the particles of the polymerizable monomer composition and the poorly soluble inorganic fine particles as a dispersion stabilizer can be obtained. When the particles of the polymerizable monomer composition are formed, a stirring device such as a TK homomixer (product name, Tokushu Kika) or the like can be used.

[0120] Step (II) is a step of polymerizing the polymerizable monomer contained in the particles of the obtained polymerizable monomer composition in water to form resin particles. During the polymerization, either or both of the oil-soluble polymerization initiator and the water-soluble polymerization initiator can be used as a polymerization initiator.

[0121] Examples of the oil-soluble polymerization initiator include nitrile-based polymerization initiators such as 2,2'-azobisisobutyronitrile, 2,2'-azobis-2,4-dimethylvaleronitrile, 1,1'-azobis(cyclohexane-1-carbonitrile), and 2,2'-azobis-4-methoxy-2,4-dimethylvaleronitrile; and peroxide-based polymerization initiators such as acetyl cyclohexyl sulfonyl peroxide, diisopropyl peroxydicarbonate, sebacoyl peroxide, lauroyl peroxide, stearyl peroxide, propionyl peroxide, acetyl peroxide, t-butylperoxy-2-ethylhexanoate, benzoyl peroxide, t-butylperoxy pivalate, t-butylperoxy isobutyrate, cyclohexanone peroxide, methyl ethyl ketone peroxide, dicumyl peroxide, t-butyl hydroperoxide, di-t-butyl peroxide, and cumene hydroperoxide, and the like.

[0122] Examples of the water-soluble polymerization initiator include aluminum persulfate, potassium persulfate, 2,2'-azobis(N,N'-dimethyleneisobutylamidine) hydrochloride, 2,2'-azobis(2-amidinopropane) hydrochloride, azobis(isobutylamidine) hydrochloride, sodium 2,2'-azobisisobutyronitrile sulfonate, ferrous sulfate, and hydrogen peroxide.

[0123] From the viewpoints of safety and polymerization efficiency, the addition amount of the polymerization initiator is preferably 0.1 to 20 parts by mass, or more preferably 0.1 to 15 parts by mass, with respect to 100 parts by mass of the polymerizable monomer. One polymerization initiator or a mixture of two or more kinds can be used with reference to the respective 10-hour half-life temperatures.

[0124] When the polymerizable monomer is polymerized to improve the stress resistance of the toner particles and to control the molecular weight of the constituent molecules of the toner particles, a crosslinking agent can be used. A compound having two or more polymerizable double bonds can be used as the crosslinking agent. Specific examples include aromatic divinyl compounds such as divinylbenzene and divinyl naphthalene; carboxylic acid esters having two double bonds such as ethylene glycol diacrylate, ethylene glycol dimethacrylate, and 1,3-butylene glycol dimethacrylate; divinyl compounds such as divinyl aniline, divinyl ether, divinyl thioether, and divinyl sulfone; and compounds having three or more vinyl groups.

[0125] Either a single crosslinking agent or a mixture of two or more can be used. From the viewpoints of toner fixing performance and stain resistance, the amount of the crosslinking agent added is preferably 0.05 parts by mass to 10 parts by mass, or more preferably 0.10 parts by mass to 5 parts by mass, with respect to 100 parts by mass of the polymerizable monomer.

[0126] A chain transfer agent and a polymerization inhibitor can also be used to control the degree of polymerization of the polymerizable monomer. Examples of the chain transfer agent include a-methylstyrene dimer, t-dodecyl mercaptan, n-dodecyl mercaptan, n-octyl mercaptan, carbon tetrachloride, and carbon tetrabromide.

[0127] Examples of the polymerization inhibitor include quinone compounds such as p-benzoquinone, chloroaniline, anthraquinone, phenanthraquinone, and dichlorobenzoquinone; organic hydroxyl compounds such as phenol, t-butylcatechol, hydroquinone, pyrocatechol, and hydroxymono-methyl ether; nitro compounds such as dinitrobenzene, dinitrotoluene, and dinitrophenol; nitroso compounds such as nitrosobenzene and nitrosonaphthol; amino compounds such as methyl aniline, p-phenylenediamine, N,N'-tetraethyl-p-phenylenediamine, and diphenylamine; and organic sulfur compounds such as tetraalkylthiuram disulfide and dibenzothioacyl disulfide.

[0128] The toner particles can also contain a colorant. The colorant can be appropriately selected from colorants known in the toner field in consideration of hue angle, chroma, brightness, weather resistance, OHT transparency, dispersibility in the toner particles, and the like. Specifically, the following black, yellow, magenta, and cyan pigments, and dyes and other colorants as needed can be used. One colorant or a mixture of a plurality of colorants can be used. The colorant can be used in the state of a solid solution.

[0129] The content of the colorant is preferably 1 part by mass to 20 parts by mass with respect to 100 parts by mass of the binder resin. For the purpose of dispersing the pigment or other colorant in the toner particles, a colorant dispersed in a solvent can be used, and a polymerizable monomer such as styrene can be used as the solvent.

[0130] A black colorant known in the field of toners can be used as the black colorant. Specific examples of the black colorant include carbon black and a black colorant obtained by blending the following yellow, magenta, and cyan colorants.

[0131] The carbon black is not particularly limited, but can be carbon black obtained by a manufacturing method such as a thermal cracking method, an acetylene method, a tank method, a furnace method, or a lamp black method. One carbon black or a mixture of two or more can be used. The carbon black can be a crude pigment, or can be a prepared pigment composition as long as it does not significantly inhibit the effect of the pigment dispersant. The number average particle diameter of the primary particles of the carbon black is not particularly limited, but is preferably 14 nm to 80 nm, or more preferably 25 nm to 50 nm.

[0132] A yellow colorant known in the field of toners can be used as the yellow colorant. Condensed polycyclic pigments, isoindolinone compounds, anthraquinone compounds, azo metal complexes, methine compounds, and allylamide compounds are representative examples of pigment-type yellow colorants. Specific examples include C.I. Pigment Yellow 3, 7, 10, 12, 13, 14, 15, 17, 23, 24, 60, 62, 74, 75, 83, 93, 94, 95, 99, 100, 101, 104, 108, 109, 110, 111, 117, 123, 128, 129, 138, 139, 147, 148, 150, 155, 166, 168, 169, 177, 179, 180, 181, 183, 185, 191:1, 191, 192, 193, and 199. Examples of dye-type yellow colorants include C.I. Solvent Yellow 33, 56, 79, 82, 93, 112, 162, and 163, and C.I. Disperse Yellow 42, 64, 201, and 211.

[0133] A magenta colorant known in the field of toners can be used as the magenta colorant. Examples of the magenta colorant include condensed polycyclic pigments, pyrrolopyrrole dione compounds, anthraquinone compounds, quinacridone compounds, basic dye lake compounds, naphthol compounds, benzimidazolone compounds, thioindigo compounds, and perylene compounds. Specific examples include C.I. Pigment Red 2, 3, 5, 6, 7, 23, 48:2, 48:3, 48:4, 57:1, 81:1, 122, 146, 150, 166, 169, 177, 184, 185, 202, 206, 220, 221, 238, 254, and 269, and C.I. Pigment Violet 19.

[0134] Known cyan colorants in the field of toners can be used as the cyan colorant. Examples of the cyan colorant include phthalocyanine compounds and derivatives thereof, anthraquinone compounds, and basic dye lake compounds. Specific examples include C.I. Pigment Blue 1, 7, 15, 15:1, 15:2, 15:3, 15:4, 60, 62, and 66.

[0135] The toner particles can further include a wax. Examples of the wax include aliphatic hydrocarbon-based waxes such as low molecular weight polyethylene, low molecular weight polypropylene, microcrystalline wax, Fischer-Tropsch wax, and paraffin wax; aliphatic hydrocarbon-based wax oxides such as polyoxyethylene wax, and block copolymers of these; waxes mainly composed of fatty acid esters such as carnauba wax and montan acid ester wax, and partially or completely deoxidized fatty acid esters such as deoxidized carnauba wax; saturated linear fatty acids such as palmitic acid, stearic acid, and montanic acid; unsaturated fatty acids such as brassidic acid, eleostearic acid, and calamenic acid; saturated alcohols such as stearyl alcohol, aralkyl alcohol, behenyl alcohol, cetylic alcohol, cerasin, and myricyl alcohol; polyhydric alcohols such as sorbitol; fatty acid amides such as linoleamide, oleamide, and lauramide; saturated fatty acid bisamides such as methylene bisstearamide, ethylene bisundecanoamide, ethylene bislauramide, and hexamethylene bisstearamide; unsaturated fatty acid amides such as ethylene bisoleamide, hexamethylene bisoleamide, N,N'-dioleyladipamide, and N,N'-dioleylsebacamide; aromatic bisamides such as m-xylylene bisstearamide and N,N'-distearylisophthalamide; aliphatic metal salts (generally referred to as metal soaps) such as calcium stearate, calcium laurate, zinc stearate, and magnesium stearate; waxes obtained by grafting aliphatic hydrocarbon-based waxes with vinyl-based monomers such as styrene or acrylic acid; partial esters of fatty acids and polyhydric alcohols such as glyceryl monobehenate; and methyl ester compounds having a hydroxyl group obtained by hydrogenation of vegetable fats and oils. One of these waxes can be used alone, or two or more of these waxes can be used in combination.

[0136] Among these, aliphatic hydrocarbon-based waxes or monoester waxes mainly composed of linear fatty acid esters are preferable. The peak temperature of the maximum endothermic peak (melting point) of the wax measured by differential scanning calorimetry (DSC) is preferably 60°C to 140°C, or more preferably 60°C to 90°C. The content of the wax is preferably 2.5 parts by mass to 25.0 parts by mass with respect to 100 parts by mass of the binder resin.

[0137] A charge control agent can also be contained in the toner particles, so that the charging performance of the toner particles is stably maintained regardless of the environment. Known charge control agents can be used, and a charge control agent that can provide a rapid charging speed while stably maintaining a fixed charge amount is particularly desirable. When the toner particles are manufactured by a direct polymerization method, a charge control agent that has a low polymerization inhibition property and virtually no soluble material in an aqueous medium is particularly preferable. In terms of specific compounds, examples of a charge control agent that provides a negative charge include metal compounds of aromatic carboxylic acids such as salicylic acid, alkyl salicylic acid, dialkyl salicylic acid, naphthoic acid, and dicarboxylic acid, metal salts or metal complexes of azo dyes and azo pigments, and boron compounds, silicon compounds, and calixarenes. Examples of a charge control agent that provides a positive charge include quaternary ammonium salts, high-molecular-type compounds having such quaternary ammonium salts in side chains, guanidine compounds, nigrosine compounds, and imidazole compounds.

[0138] One charge control agent can be used, or two or more can be used in combination. As the charge control agent, a metal-containing salicylic acid compound is preferable, and the metal in this case can be aluminum or zirconium. As the charge control agent, an aluminum salicylate compound is preferable. However, a resin charge control agent can also be used. Specific examples include polymers or copolymers having sulfonic acid groups, sulfonate groups, sulfonate ester groups, salicylic acid sites, or benzoic acid sites. The content of the charge control agent is preferably 0.01 to 20 parts by mass, or more preferably 0.05 to 10 parts by mass, with respect to 100 parts by mass of the binder resin.

[0139] Step (III) is a step of keeping the resin particles obtained in Step (II) in an aqueous medium having a pH higher than the acid dissociation constant pKa of the resin B at a temperature above the glass transition temperature of the resin B. As discussed above, since the resin B is a high molecule, its molecular movement is slow in the toner particles. Therefore, by performing a step of keeping the resin particles in an aqueous medium having a pH higher than the acid dissociation constant pKa of the resin B at a temperature above the glass transition temperature (Tg) of the resin B, the resin B can be actively caused to preferentially locate on the surface of the toner particles.

[0140] The keeping time is preferably 30 minutes to 6 hours, or more preferably 1 hour to 5 hours. The pH of the aqueous medium before this keeping step (III), or in other words, in Step (I) and / or Step (II), is preferably less than the acid dissociation constant pKa of the resin B, so that the resin B preferentially locates on the surface of the toner particles to an appropriate extent.

[0141] In the production method, a distillation step can also be performed between step (II) and step (III). The distillation step is a step for removing volatile impurities such as unreacted polymerizable monomers and by-products. The distillation step can be performed under normal pressure (101,325 Pa) or under reduced pressure (0.5 to 0.95 kPa).

[0142] In the production method, after step (III), the dispersion liquid containing the resin particles can also be treated with an acid or a base to remove the dispersion stabilizer adhering to the surface of the resulting resin particles. At this stage, the resin particles are separated into a solid phase by a conventional solid-liquid separation method, and water can also be added again in this process to wash the resin particles and completely remove the acid or base and the dispersion stabilizer dissolved therein. This washing can be repeated several times, and after sufficient washing is completed, solid-liquid separation can be performed again, thereby obtaining toner particles. Then, the resulting toner particles can be dried as needed by a known drying method.

[0143] The resulting toner particles can also have an external additive or the like on the surface thereof to impart various properties to the toner. In order to make the external additive more durable on the surface of the toner particles, the external additive preferably has a particle diameter of 1 / 10 or less of the weight average particle diameter of the toner particles before the external additive is added.

[0144] Examples of the external additive include metal oxides such as alumina, titania, strontium titanate, ceria, magnesia, chromia, tin oxide, and zinc oxide; nitrides such as silicon nitride; carbides such as silicon carbide; inorganic metal salts such as calcium sulfate, barium sulfate, and calcium carbonate; fatty acid metal salts such as zinc stearate and calcium stearate; and carbon black and silica.

[0145] The content of the external additive is preferably 0.01 to 10 parts by mass or more preferably 0.05 to 5 parts by mass with respect to 100 parts by mass of the toner particles. One external additive can be used, or a plurality of them can be combined.

[0146] From the viewpoint of charge stability, it is desirable to use an external additive that is subjected to a hydrophobizing treatment on the surface. Methods of the hydrophobizing treatment include surface treatment with a silane coupling agent such as methyltrimethoxysilane, methyltriethoxysilane, isobutyltrimethoxysilane, dimethyldimethoxysilane, dimethyldiethoxysilane, trimethylmethoxysilane, and hexamethylenedisilazane.

[0147] The toner can be applied to the image forming method using a known one-component developing system or a two-component developing system, or the like. The toner can also be used in any kind of system. Examples include a toner for a high-speed system, a toner for an oilless fixing, a toner for a cleanerless system, and a toner for a developing system in which a carrier deteriorated in a developing device during long-term use is replenished with a new carrier.

[0148] The following describes a measurement method of various physical properties of the toner.

[0149] Calculation of surface roughness index

[0150] The toner was observed with a scanning electron microscope, and the surface unevenness index of the toner was calculated from a measured value from the resulting image by the following formula (1).

[0151] Surface unevenness index = (area of a region enclosed by a convex hull of the toner - projected area of the toner) / projected area of the toner (1)

[0152] The specific observation method and image measurement method are as follows.

[0153] First, the toner was magnified to 100,000 to 200,000 times using a scanning electron microscope (SEM) "S-4800" (Hitachi). The image was taken in such a manner that toner particles individually appearing in the resulting field of view were within ±2.0 μm of the weight average particle diameter of the toner.

[0154] Image processing was performed so that the external additive on the toner surface could be negligible in the resulting image, and then binarization and image processing were performed to calculate the surface unevenness index of the toner.

[0155] The binarization conditions were appropriately selected depending on the observation equipment. Image-Pro Plus 5.1J (Media Cybernetics) was used for binarization, and a background brightness distribution was removed from the Subtract Background menu at a flattening radius of 40 pixels, and then the image was binarized at a brightness threshold of 50, thereby obtaining a binarized image.

[0156] The resulting binarized image was subjected to particle analysis using the Image-Pro Plus 5.1J image analysis software to calculate the surface unevenness index of the toner. The calculation steps are shown below.

[0157] (1) The scale was set using [Analysis] - [Set Scale].

[0158] (2) Sigma (radius) was set to 1.7 using [Process] -> [Filters] -> [Gaussian Blur].

[0159] (3) Select "Huang" under [Image] - [Adjust] - [Threshold], input "Dark background" check, and determine the threshold by changing the value to fill the particles in red.

[0160] (4) Use [Analyze] -> [Analyze Particles], set the size (Pixcel^2) to 50 to infinity, and set the circularity to 0.0 to 1.00. Input the check for the following 6 items: Show results, Clear results, Summarize, Add to Manager, Exclude on edges, Include holes.

[0161] Set "Show" to "None" to generate an execution window.

[0162] The "Total area" in the resulting "Summary" window is the projected area of the toner.

[0163] (5) Input the pixels displayed on the particle image window generated by "Copy" under [File] -> [New] -> [Image].

[0164] (6) Select the ROI Manager, select the number corresponding to the toner on the ROI Manager, and confirm that the line of the toner shape appears in the black image portion of the generated window.

[0165] (7) Execute [Edit] -> [Select] -> [Convex].

[0166] (8) Execute [Edit] -> [Invert].

[0167] (9) Delete the yellow frame of the selected window (erase the yellow frame by clicking once in the window), and then execute [Edit] -> [Invert] again.

[0168] (10) Under [Analyze] -> [Analyze Particles], set the size (Pixcel^2) to 5 to infinity, and set the circularity to 0.1 to 1.00. Input the check for the following 6 items: Show results, Clear results, Summarize, Add to Manager, Exclude on edges, Include holes.

[0169] Set "Show" to "None" to generate an execution window.

[0170] The "Total area" in the resulting "Summary" window is the area of the region surrounded by the convex hull of the toner.

[0171] The surface unevenness index of the toner is calculated using the projected area of the toner and the area of the region surrounded by the convex hull of the toner.

[0172] The arithmetic mean of the standard deviations of the surface unevenness indices obtained by these measurements was taken as the "standard deviation of the surface unevenness index of the toner".

[0173] Calculation of shape factor SF-1 and shape factor SF-2

[0174] The shape factor SF-1 and the shape factor SF-2 of the toner were calculated by the following methods.

[0175] The toner was observed with a scanning electron microscope (SEM) "S-4800" (Hitachi).

[0176] In a field of view magnified 100,000 to 200,000 times, the projected maximum length, the projected area, and the projected perimeter of 100 toner particles were measured with the Image-Pro Plus 5.1J image processing software (Media Cybernetics), and the shape factor SF-1 and the shape factor SF-2 were each calculated by the following formula. The arithmetic mean of the shape factor SF-1 and the shape factor SF-2 of the 100 toner particles was taken as the shape factor SF-1 and the shape factor SF-2.

[0177] Shape factor SF-1 = (projected maximum length of toner) 2 / (projected area of toner) x (π / 4) x 100

[0178] Shape factor SF-2 = (projected perimeter of toner) 2 / (projected area of toner) / 4π x 100

[0179] The following describes the calculation steps using the Image-Pro Plus 5.1J software.

[0180] (1) Set the scale using [Analysis] - [Set Scale].

[0181] (2) Set Sigma (radius) to 1.7 using [Process] -> [Filters] -> [Gaussian Blur].

[0182] (3) Select "Huang" under [Image] - [Adjust] - [Threshold], input "Dark Background" check, and determine the threshold by changing the value to fill the particles in red.

[0183] (4) In [Analysis] -> [Analyze Particles], set the size (Pixcel2) to 50 to infinity, and the circularity to 0.0 to 1.00. Enter the check for the following 6 items: Show Results, Clear Results, Summary, Add to Manager, Exclude on Edges, Include Holes.

[0184] Set "Show" to "None" to generate an execution window.

[0185] "Feret X" in the resulting "Summary" window becomes the projected short diameter of the toner, "Feret Y" becomes the projected maximum length of the toner, and Perim becomes the projected perimeter of the toner, thereby giving the projected area of the toner. These values are entered into the above equation to obtain SF-1 and SF-2.

[0186] Calculation of As and Ac

[0187] In the cross section of the toner observed under a transmission electron microscope, assuming that As is the percentage (%) of the area occupied by the wax in the region defined by the contour of the toner and the line drawn 1.0 μm from the contour in the direction along the inside of the toner, and Ac is the percentage (%) of the area occupied by the wax in the internal region inward from the line drawn 1.0 μm from the contour in the direction along the inside of the toner, As and Ac are calculated as follows.

[0188] The distribution state of the wax in the toner is evaluated by observing the cross section of the toner under a transmission electron microscope, calculating As and Ac from the cross-sectional area of the domain formed by the wax, and calculating the average of 10 randomly selected toner particles.

[0189] In detail, the toner is embedded in a visible light-curable embedding resin (D-800, Nisshin EM), cut into a thickness of 60 nm with an ultrasonic ultramicrotome (EM5, Leica), and Ru-stained with a vacuum staining apparatus (Filgen) (RuO4 gas, 500 Pa atmosphere, 15 minutes of staining).

[0190] It is then observed with a transmission electron microscope (H7500, Hitachi) at an acceleration voltage of 120 kV. In the cross section of the toner under observation, 10 toner particles within ±2.0 μm of the weight average particle diameter of the toner are selected and photographed.

[0191] Image processing software (Photoshop 5.0, Adobe) is used to clearly distinguish the wax domain from the region of the binder resin in the resulting image.

[0192] In detail, the wax domains can be distinguished as follows. In the image processing software, the threshold value of the brightness of the enclosed TSM image is set to 160 (out of 255 gradations), and the image is binarized. The wax in the toner and the visible light-curable embedding resin (D-800) become bright portions, while the portions other than the wax in the toner become dark portions. The profile of the toner section can be distinguished by the brightness of the toner and the visible light-curable embedding resin.

[0193] The image except for the region defined by the toner profile and the line drawn 1.0 μm from the profile in the direction of the inside of the toner (including the 1.0 μm line itself) is masked. Specifically, a line is drawn from the center of gravity of the toner section to a point on the profile of the toner section. Then, a position 1.0 μm from the profile in the direction of the center of gravity is designated on the line. Then, this operation is performed completely around the profile of the toner section, and the region defined by the toner profile and the line drawn 1.0 μm from the profile in the direction of the inside of the toner is clearly shown. The area percentage of the wax domains in this region is calculated and taken as Asl. This operation is performed on 10 toner particles, and the arithmetic mean value As (area %) of the resulting As values is obtained.

[0194] The area percentage of the wax domains in the internal region inward from the line drawn 1.0 μm from the profile in the direction of the inside of the toner with respect to the area of the internal region is also calculated and taken as Ac1. This operation is performed on 10 toner particles, and the arithmetic mean value Ac (area %) of the resulting Ac values is obtained.

[0195] Measurement of glass transition temperature (Tg) of resin

[0196] The glass transition temperature (Tg) is measured using a differential scanning calorimeter "Q2000" (TA Instruments) in accordance with ASTM D3418-82. The melting points of indium and zinc are used for temperature correction of the detector of the apparatus, and the heat of fusion of indium is used for correction of the heat value.

[0197] Specifically, 2 mg of the resin is accurately weighed and put in an aluminum pan, and an empty aluminum pan is used for reference. The measurement is performed at a temperature range of 30°C to 200°C at a temperature rising rate of 10°C / min.

[0198] During the measurement, the temperature is first raised to 200°C, then lowered to 30°C at a rate of 10°C / min, and then raised again. During this second temperature rise, a specific heat change occurs in a temperature range of 40°C to 100°C. The intersection between the curve of the step change portion of the glass transition defined between the straight lines extended from the baseline before and after the occurrence of the specific heat change and the line equidistant from the ordinate direction is defined as the glass transition temperature (Tg: °C) of the resin.

[0199] Measurement of softening point of resin

[0200] The softening point (°C) of the resin was measured using a constant load extrusion type capillary rheometer "Flow Tester CFT-500D" (Shimadzu Corp.) in accordance with the manual attached to the apparatus. For the apparatus, a fixed load was applied from above the measurement sample with a piston while the temperature of the measurement sample charged in a cylinder was raised to melt the sample, and the melted measurement sample was extruded through a die at the bottom of the cylinder. This series of steps obtained a relationship showing the temperature and the amount of lowering of the piston.

[0201] In these publications, the softening point is the "melting point of the 1 / 2 method" described in the manual of the "Flow Tester CFT-500D". The melting point of the 1 / 2 method is calculated as follows. First, the half of the difference between the piston lowering amount at the time of completion of the flow-out Smax and the piston lowering amount at the time of start of the flow-out Smin is calculated and taken as X (X = (Smax - Smin) / 2). Then, the temperature of the flow curve at the sum of X and Smin of the piston lowering amount is taken as the melting point of the 1 / 2 method.

[0202] For the measurement sample, 1.00 g of the resin was compression molded into a cylinder having a diameter of 8 mm using a tablet compression machine (NT-100H, NPA System) at 10 MPa for 60 seconds.

[0203] The CFT-500D measurement conditions were as follows.

[0204] Test mode: temperature raising method

[0205] Starting temperature: 50°C

[0206] Reaching temperature: 200°C

[0207] Measurement interval: 1.0°C

[0208] Temperature raising rate: 4.0°C / min

[0209] Piston cross-sectional area: 1.000 cm 2

[0210] Test load (piston load): 10.0 kgf (0.9807 MPa)

[0211] Preheating time: 300 seconds

[0212] Die hole diameter: 1.0 mm

[0213] Die length: 1.0 mm

[0214] Measurement of acid value of resin and acid dissociation constant pKa of resin

[0215] The acid value of the resin is the number of milligrams of potassium hydroxide required to neutralize the acid contained in 1 g of sample. The acid value of the resin is measured in accordance with JIS K 0070-1992, specifically, by the following steps.

[0216] First, titration was performed with 0.1 mol / L potassium hydroxide ethanol solution (Kishida Chemical). The factor of the potassium hydroxide ethanol solution was measured with a potentiometric titration device (Kyoto Electronics, Potentiometric Titration Measuring Equipment AT-510 (product name)). Specifically, 100 mL of 0.100 mol / L hydrochloric acid was charged into a 250 mL beaker and titrated with the potassium hydroxide ethanol solution to measure the amount of potassium hydroxide ethanol solution required for neutralization. The 0.100 mol / L hydrochloric acid was prepared in accordance with JIS K 8001-1998. The measurement conditions for acid value measurement are given below.

[0217] Titration cell: Potentiometric Titration Device AT-510 (product name, manufactured by Kyoto Electronics)

[0218] Electrode: Composite glass double junction electrode (manufactured by Kyoto Electronics)

[0219] Titration cell control software: AT-WIN

[0220] Titration analysis software: Tview

[0221] The titration parameters and control parameters during titration were set as follows.

[0222] Titration parameters

[0223] Titration mode: Blank titration

[0224] Titration method: Total titration

[0225] Maximum titration amount: 20 mL

[0226] Waiting time before titration: 30 seconds

[0227] Titration direction: Automatic

[0228] Control parameters

[0229] End point judgment potential: 30 dE

[0230] End point judgment potential value: 50 dE / dmL

[0231] End point detection judgment: Not set

[0232] Control speed mode: Standard

[0233] Gain: 1

[0234] Data collection potential: 4 mV

[0235] Data collection titration volume: 0.1 mL

[0236] Main test

[0237] A 0.100 g measured sample (resin) was precisely weighed into a 250 mL high form beaker, 150 mL of mixed toluene / ethanol solution (3:1) was added, and the sample was dissolved over a period of 1 hour. Titration was performed using the above-mentioned potentiometric titrator with the above-mentioned potassium hydroxide ethanol solution.

[0238] Blank test

[0239] The titration was performed as above except that no sample was used (only mixed toluene / ethanol (3:1) solution was used). The results were substituted into the following equation to calculate the acid value of the resin (Av: unit mgKOH / g).

[0240] Av = [(C - B) x f x 5.61] / S

[0241] In the above equation, Av is the acid value (mgKOH / g), B is the amount of potassium hydroxide ethanol solution added in the blank test (ml), C is the amount of potassium hydroxide ethanol solution added in the main test (ml), f is the factor of the potassium hydroxide ethanol solution, and S is the mass of the sample (resin) (g). Since the pKa is the same value as the pH at the time of reaching half the amount of 0.1 mol / L potassium hydroxide ethanol solution required to reach the neutralization point, the pH at the time of half the amount was read from the titration curve.

[0242] Measurement of particle diameter of toner

[0243] The particle diameter of the toner was measured using a precision particle size distribution measuring apparatus based on the pore resistance method (product name: Coulter Counter Multisizer 3) and dedicated software (product name: Beckman Coulter Multisizer 3 Version 3.51 software, Beckman Coulter). The orifice diameter was set to 100 μm, measurement was performed with 25,000 effective measurement channels, and the data was analyzed.

[0244] The electrolyte aqueous solution used for measurement was a solution in which special grade sodium chloride was dissolved in deionized water to a concentration of about 1 mass%, such as Beckman Coulter Isoton II (product name). Prior to measurement and analysis, the dedicated software was set as follows.

[0245] In the "Change Standard Operating Method (SOM)" screen of the dedicated software, the total number of control modes was set to 50,000 particles, the number of measurements was set to 1, and the Kd value was set to the value obtained using "Standard Particle 10.0 pm (Beckman Coulter)". The threshold and noise levels were automatically set by pressing the "Threshold / Noise Level" button. The current was set to 1,600 pA, the gain was set to 2, the electrolyte was set to Isoton II (product name), and the "Post Measurement Tip Flush" was checked. In the "Pulse to Size Conversion Settings" screen of the dedicated software, the element interval was set to logarithmic size, and the size element was set to 256 size elements with a size range of 2 pm to 60 pm. The specific measurement method was as follows.

[0246] (1) 200 mL of the above-described aqueous electrolyte solution was placed in a 250 mL round-bottom glass beaker dedicated to the Multisizer 3, the beaker was placed in the sample stage, and stirring with a stir bar was performed at 24 revolutions per minute counterclockwise. The inside of the tip was removed of dirt and air bubbles by the "Tip Flush" function of the dedicated software.

[0247] (2) 30 mL of the aqueous electrolyte solution was placed in a 100 mL flat-bottom glass beaker, and about 0.3 mL of a diluent obtained by diluting Contaminon N (product name) (10 mass% aqueous solution of a neutral detergent for washing precision measuring instruments, manufactured by Wako Pure Chemical Industries) with deionized water by 3 mass times was added thereto.

[0248] (3) A predetermined amount of deionized water and about 2 mL of Contaminon N (product name) were placed in the water tank of an ultrasonic disperser (product name: Ultrasonic Dispersion System Tetora 150, Nikkaki Bios) having a 120 W power output, equipped with two built-in oscillators with an oscillation frequency of 50 kHz configured so that the phase thereof is shifted by 180 degrees.

[0249] (4) The beaker of the above-described (2) was set in the beaker fixing hole of the ultrasonic disperser, and the ultrasonic disperser was activated. The vertical position of the beaker was adjusted to maximize the resonance state of the liquid level of the electrolyte solution in the beaker.

[0250] (5) As the aqueous electrolyte solution was exposed to ultrasonic waves, about 10 mg of toner was gradually added to and dispersed in the aqueous electrolyte solution in the beaker of the above-described (4). Then, the ultrasonic dispersion was continued for another 60 seconds. During the ultrasonic dispersion, the water temperature in the water tank was appropriately adjusted so that it was 10°C to 40°C.

[0251] (6) The electrolyte aqueous solution of the above (5) containing the dispersed toner was dropped into the round-bottomed beaker of the above (1) provided in the sample stage with a pipette to adjust the measurement concentration to about 5%. Then, measurement was performed until the measured particle number reached 50,000.

[0252] (7) The measurement data were analyzed with the above dedicated software attached to the apparatus to calculate the weight average particle diameter (D4) or the number average particle diameter (D1). The weight average particle diameter (D4) was the "average diameter" on the "analysis / volume statistics (arithmetic mean)" screen when a graph / volume% was set in the dedicated software, and the number average particle diameter (D1) was the "average diameter" on the "analysis / number statistics (arithmetic mean)" screen when a graph / number% was set in the dedicated software.

[0253] Measurement of average circularity of toner

[0254] The average circularity of the toner was measured using a flow-type particle image analyzer "FPIA-3000" (Sysmex) under the measurement and analysis conditions of the calibration operation. The specific measurement method was as follows.

[0255] First, 20 mL of deionized water from which solid impurities had been removed was put into a glass container. To this, about 0.2 mL of "Contaminon N" (10 mass% aqueous solution of a pH 7 neutral cleaner for cleaning precision measurement instruments, which contains a nonionic surfactant, an anionic surfactant, and an organic builder, manufactured by Wako Pure Chemical Industries) diluted with deionized water by about 3 mass times was added as a dispersant. Then, 0.02 g of the measurement sample was added and dispersed for 2 minutes using an ultrasonic disperser to obtain a dispersion liquid for measurement. Cooling was appropriately performed during this process so that the temperature of the dispersion liquid was 10°C to 40°C. As the disperser, a table-type ultrasonic cleaner and disperser (e.g., "VS-150", Velvo-Clear) having a vibration frequency of 50 kHz and an electric output of 150 W was used, a predetermined amount of deionized water was put into a water tank, and about 2 mL of Contaminon N was added to the water tank.

[0256] The measurement was performed using a "LUCPLFLN" objective lens (magnification 20x, aperture: 0.40) mounted on the above-described flow-type particle image analyzer, and a Sheath "PSE-900A" (Sysmex) was used as the sheath liquid. The dispersion liquid prepared according to the above-described procedure was introduced into the flow-type particle image analyzer, and 2,000 toner particles were measured in the HPF measurement mode in the total counting mode. Then, with the binarization threshold at the time of particle analysis set to 85% and the analyzed particle diameter limited to a circular equivalent diameter of 1.977 μm or more and less than 39.54 μm, the average circularity of the toner particles was determined.

[0257] Prior to the start of the measurement, a standard latex particle (Duke Scientific "Research and Test Particles Latex Microsphere Suspensions 5100A", diluted with deionized water) was used for the automatic focus adjustment. Thereafter, the focus adjustment was preferably performed every two hours after the start of the measurement.

[0258] The flow-type particle image analyzer was a flow-type particle image analyzer calibrated by Sysmex Corp. and having received a calibration certificate issued by Sysmex Corp. The measurement and the analysis conditions for the measurement were the same as at the time of issuance of the calibration certificate, except that the analyzed particle diameter was limited to a circular equivalent diameter of 1.977 μm or more and less than 39.54 μm.

[0259] Example

[0260] Hereinafter, the examples and comparative examples are described in more detail. However, these disclosures are not limited by these examples and comparative examples. The parts and % in the examples and comparative examples are based on mass, unless otherwise specified.

[0261] Example of production of resin B: polyester resin 1

[0262] The acid component and the alcohol component in the amounts shown in Table 1 below were placed in a reaction vessel equipped with a nitrogen introduction tube, a dehydration tube, a stirrer, and a thermocouple, and dibutyl tin was added as a catalyst in an amount of 1.5 parts relative to 100 parts of the total monomers. Then, the temperature was rapidly increased to 180°C under a nitrogen atmosphere at normal pressure, after which the mixture was heated from 180°C to 210°C at a rate of 10°C / hour while distilling water to perform polycondensation. Once the temperature reached 210°C, the reaction vessel was depressurized to 5 kPa or less, and polycondensation was performed at 210°C under a condition of 5 kPa or less to obtain a polyester resin 1. The polymerization time was adjusted in this process so that the softening point of the obtained polyester resin 1 was 126°C. The physical properties of the obtained polyester resin 1 are shown in Table 1.

[0263] Example of production of resin B: polyester resins 2 to 5

[0264] Polyester resins 2 to 5 were produced by the same production operation as polyester resin 1 except that the compounding amounts of the acid component and the alcohol component were changed as shown in Table 1. The physical properties of the resulting polyester resins 2 to 5 are shown in Table 1.

[0265] [Table 1]

[0266]

[0267] TPA: terephthalic acid

[0268] TMA: trimellitic anhydride

[0269] BPA (PO): bisphenol A propylene oxide 2-mol adduct

[0270] BPA (EO): bisphenol A ethylene oxide 2-mol adduct

[0271] EG: ethylene glycol

[0272] IS: isosorbide

[0273] The glass transition temperature in the table is in °C, and the acid value is in mgKOH / g.

[0274] Example of production of toner 1

[0275] Preparation of water-based medium

[0276] To a granulation tank, 100.0 parts of deionized water, 2.0 parts of sodium phosphate, and 0.9 parts of hydrochloric acid having a concentration of 10 mass% of hydrogen chloride were added, and heated and maintained at 50°C. Then, 1.2 parts of a calcium chloride aqueous solution in which calcium chloride hexahydrate was dissolved in 8.2 parts of deionized water was added thereto. After the addition, it was stirred with a TK homomixer (Tokushu Kika) at a circumferential speed of 25 m / s for 30 minutes, to thereby obtain a pH 5.0 aqueous medium containing poorly water-soluble inorganic fine particles.

[0277] Preparation of polymerizable monomer composition

[0278] Preparation of dispersed pigment composition

[0279] • styrene 39.0 parts

[0280] • carbon black 6.5 parts

[0281] (Nipex 35, Evonik Japan)

[0282] The materials were introduced into a mill (Nippon Coke & Engineering) and stirred with zirconium oxide beads having a radius of 1.25 mm at 25°C, 200 rpm for 180 minutes, and the zirconium oxide beads were removed, thereby preparing a dispersed pigment composition.

[0283] Preparation of polymerizable monomer composition

[0284] The following materials were put into the same container and mixed and dispersed with a TK homomixer (Tokushu Kika) at a peripheral speed of 20 m / s.

[0285]

[0286] It was further heated to 60°C, 5.0 parts of a hydrocarbon wax (melting point: temperature of the largest endothermic peak: 77°C) and 9.0 parts of a behenyl behenate wax (melting point: temperature of the largest endothermic peak: 72°C) were added, and the mixture was dispersed and mixed for 30 minutes, thereby obtaining a polymerizable monomer composition.

[0287] Step (I)

[0288] The polymerizable monomer composition was added to an aqueous medium containing a poorly water-soluble inorganic fine particle, and stirred with a TK homomixer (Tokushu Kika) at a peripheral speed of 30 m / s under a nitrogen atmosphere at 60°C. 6.0 parts of a polymerization initiator, t-hexyl peroxy pivalate (NOF Corp., product name "Perhexyl PV", molecular weight: 202, 10-hour half-life temperature: 53.2°C) was dissolved therein, thereby preparing a polymerizable monomer composition containing a polymerization initiator.

[0289] Step (II)

[0290] The dispersion of the particles containing the polymerizable monomer composition was transferred to a tank and heated to 70°C under stirring with a paddle, and the polymerizable monomer contained in the particles of the polymerizable monomer composition was allowed to undergo a polymerization reaction for 6 hours. Then, it was further heated to 90°C and reacted for 6 hours to form resin particles.

[0291] Distillation step

[0292] After the completion of the polymerization step, the supply of water vapor at 120°C to the slurry containing the aqueous medium and the resin particles was started at a flow rate of 30.0 parts / hour. After the start of the water vapor supply, distillation was started once the temperature reached 98°C and was performed for 8 hours.

[0293] Step (III)

[0294] After the distillation step was completed, 7.0% of an aqueous sodium carbonate solution was added to the slurry containing the aqueous medium and the resin particles to change the pH of the aqueous medium to 8.0. This was then maintained at 80°C for 1 hour.

[0295] Washing, filtration, drying and fractionation step

[0296] After the step (III) was completed, the mixture was cooled, adjusted to pH 1.4 with hydrochloric acid, and stirred for 2 hours, thereby obtaining an aqueous dispersion containing toner particles. The toner particles were filtered out of the aqueous dispersion, water-washed, dried at 40°C for 48 hours and classified, thereby obtaining toner particles 1.

[0297] External addition step

[0298] 0.5 parts of hydrophobic silica particles having a number average particle diameter of 20 nm, which were once particles surface-treated with 25 mass% hexamethyldisilazane, were added to 100.0 parts of the toner particles 1 and mixed in a Henschel mixer (Mitsui Miike, FM-10), thereby obtaining toner 1. The temperature of the Henschel mixer was adjusted so that the temperature of the mixture was 30°C.

[0299] Items regarding the main formulation and manufacturing conditions of the toner 1 are shown in Table 2.

[0300] [Table 2]

[0301]

[0302] In the table, A indicates a hydrocarbon wax (melting point: temperature of the largest endothermic peak: 77°C), B indicates a behenyl behenate (melting point: 72°C), and C indicates a pentaerythritol stearate (melting point: 72°C).

[0303] Example of production of toner 2 to 18

[0304] Toner 2 to 18 were obtained in the same manner as in the production example of the toner 1 except that the formulation and the manufacturing conditions were changed as shown in Table 2.

[0305] Example of production of toner 19

[0306] Preparation of resin B particle dispersion liquid 1

[0307] 100.0 parts of the polyester resin 1 and 350 parts of deionized water were put in a stainless steel container and heated to 95°C under a water bath and melted. Then, with the addition of 0.1 mol / L sodium bicarbonate to increase the pH to more than 7.0, it was sufficiently stirred with a homogenizer (IKA, Ultra-Turrax T50) at 7,800 rpm.

[0308] Then, a mixed solution of 3 parts of sodium dodecylbenzenesulfonate and 300 parts of deionized water was gradually added dropwise to emulsify and disperse the mixture and obtain a polyester resin particle dispersion liquid. The dispersion liquid was cooled to room temperature, and deionized water was added to obtain a resin B particle dispersion liquid 1 having a solid content concentration of 12.5 mass% and a median diameter of 0.2 μm on a volume basis.

[0309] Preparation of resin A particle dispersion liquid 2

[0310] A mixed solution of 78.0 parts of styrene, 20.7 parts of n-butyl acrylate, 1.3 parts of acrylic acid as a monomer to impart a carboxyl group, and 3.2 parts of n-lauryl mercaptan was mixed and dissolved. An aqueous solution containing 1.5 parts of Neogen RK (Daiichi Kogyo) in 150 parts of deionized water was added to disperse the mixture.

[0311] Then, an aqueous solution containing 0.3 parts of potassium persulfate in 10 parts of deionized water was added, and it was slowly stirred for an additional 10 minutes. The system was purged with nitrogen, and emulsion polymerization was performed at 70°C for 6 hours. After the polymerization was completed, the reaction solution was cooled to room temperature, and deionized water was added to obtain a resin A particle dispersion liquid 2 having a solid content concentration of 12.5 mass% and a median diameter of 0.2 μm on a volume basis.

[0312] Preparation of wax dispersion liquid

[0313] A mixed solution of 100 parts of a hydrocarbon wax (melting point: 77°C) and 15 parts of Neogen RK and 385 parts of deionized water was dispersed with a JN100 wet jet mill (Jokoh) for about 1 hour to obtain a wax dispersion liquid. The solid content concentration of the wax dispersion liquid was 20 mass%.

[0314] Preparation of colorant dispersion liquid

[0315] A mixed solution of 100 parts of carbon black "Nipex 35 (Orion Engineered Carbons)" and 15 parts of Neogen RK and 885 parts of deionized water was dispersed with a JN100 wet jet mill for about 1 hour to obtain a colorant dispersion liquid 1.

[0316] Preparation of toner particle

[0317] Particle growth step

[0318] The 54 parts of the resin B particle dispersion liquid 1, 250 parts of the resin A particle dispersion liquid 2, 20 parts of the wax dispersion liquid, and 20 parts of the colorant dispersion liquid were mixed, and dispersed with a homogenizer (IKA, Ultra-Turrax T50). The temperature in the container was adjusted to 30°C under stirring, and 1 mol / L aqueous sodium hydroxide solution was added to adjust the pH to 8.0 (pH adjustment 1).

[0319] A solution of 0.25 parts of aluminum chloride dissolved in 10 parts of deionized water was added as a flocculant at 30°C under stirring over a period of 10 minutes. It was left for 3 minutes, after which heating was started, and the mixture was heated to 50°C, thereby producing aggregated particles. Then, the particle size of the aggregated particles was measured in this state with a "Coulter Counter Multisizer 3" (registered trademark, Beckman Coulter). Once the weight average particle size reached 6.6 μm, 0.9 parts of sodium chloride and 5.0 parts of Neogen RK were added to stop the particle growth.

[0320] Spheroidization step

[0321] 1 mol / L aqueous sodium hydroxide solution was added to adjust the pH to 8.5, and then the temperature was raised to 95°C and the aggregated particles were spheroidized at this temperature for 5 hours. Then, it was cooled to room temperature, thereby obtaining a toner particle dispersion liquid 1.

[0322] Washing, filtration, drying and fractionation step

[0323] Hydrochloric acid was added to the resulting toner particle dispersion liquid 1 to adjust the pH to 1.5 or less, and the dispersion liquid was left for 1 hour under stirring, and then solid-liquid separation was performed in a filter press, thereby obtaining a toner filter cake. It was reslurried with deionized water to obtain a dispersion liquid again, and then solid-liquid separation was performed in the same filter unit. Reslurrying and solid-liquid separation were repeated until the conductivity of the filtrate was 5.0 μS / cm or less, after which a final solid-liquid separation was performed to obtain a toner filter cake. The resulting toner filter cake was dried, and then classified with a classifier to a weight average particle size of 6.0 μm, thereby obtaining a toner particle 19.

[0324] External addition step

[0325] 0.5 parts of hydrophobic silica particles of 20 nm in number average particle size of primary particles surface-treated with 25 mass% hexamethyldisilazane were added to 100.0 parts of the toner particle 19, and mixed in a Henschel mixer (Mitsui Miike, FM-10), thereby obtaining a toner 19. The temperature of the Henschel mixer was adjusted so that the temperature of the mixture was 30°C. Matters on the toner 19 production conditions are shown in Table 3.

[0326] [Table 3]

[0327]

[0328] Example of production of toner 20 to 22

[0329] Except for changing the manufacturing conditions as shown in Table 3, toners 20 to 22 were obtained in the same manner as in the manufacturing example of toner 19.

[0330] Example of production of toner 23

[0331]

[0332] These materials were dispersed with a grinder (Mitsui Kinzoku) for 3 hours and left for 72 hours, thereby obtaining a mixed colorant dispersion liquid.

[0333] Meanwhile, 0.25 parts of aluminum chloride was added to 220 parts of deionized water and heated to 65°C, after which 20 parts of a 1.0 mol / L CaCl2aqueous solution was added to prepare an aqueous medium. The previously mixed colorant dispersion liquid was added to this aqueous medium and stirred at 12,000 rpm for 15 minutes at 65°C under a nitrogen atmosphere with a TK homogenizer (Tokushu Kika), thereby forming particles of the mixed colorant dispersion liquid. Then, the internal temperature was lowered to 30°C, and the mixture was left as is for 12 hours to remove the solvent, and an aqueous medium having dispersed resin particles was obtained.

[0334] Hydrochloric acid was added to the aqueous medium having dispersed resin particles to lower the pH to 1.4, and the dispersant was dissolved by stirring for 1 hour. The dispersion liquid was filtered out with a pressure filter, and the resulting wet resin particles were washed to obtain a toner filter cake. Then, this toner filter cake was pulverized and dried, thereby obtaining toner particles 23.

[0335] 0.5 parts of hydrophobic silica particles having a number average particle diameter of 20 nm of primary particles surface-treated with 25 mass% hexamethyldisilazane were added to 100.0 parts of toner particles 23 and mixed in a Henschel mixer (Mitsui Miike, FM-10), thereby obtaining toner 23. The temperature of the Henschel mixer was adjusted so that the temperature of the mixture was 30°C.

[0336] Matters regarding the main formulation and manufacturing conditions of toner 23 are shown in Table 4.

[0337] [Table 4]

[0338]

[0339] In the table, A indicates a hydrocarbon wax (melting point: temperature of the largest endothermic peak: 77°C) and B indicates behenyl behenate (melting point: 72°C).

[0340] Example of production of toner 24 to 27

[0341] Except for changing the formulation and the manufacturing conditions as shown in Table 4, toners 24 to 27 were obtained in the same manner as in the production example of toner 23.

[0342] Example of production of toner 28

[0343]

[0344] The formulation was mixed in a Henschel mixer (FM-75, Mitsui Miike), and then, melt-kneaded in a twin-screw kneader (PCM-30, Ikegai) set at a temperature of 120°C. The kneaded product was cooled and coarsely pulverized to 1 mm or less in a hammer mill, thereby obtaining a broken product. A mechanical pulverizer (T-250, Turbo Kogyo) was used to obtain a pulverized resin particle product from the broken product.

[0345] Spheroidization step

[0346] The pulverized resin particle product was spheroidized in a hot air at 280°C using a Meteorainbow surface modifier (Nippon Pneumatic). Then, classified using an air-type classifier (Elbo Jet PURO, Matsubo), thereby obtaining toner particles 28.

[0347] 0.5 parts of hydrophobic silica particles having a number average particle diameter of 20 nm, which were once particles surface-treated with 25 mass% hexamethyldisilazane, were added to 100.0 parts of the toner particles 28, and mixed in a Henschel mixer (Mitsui Miike, FM-10), thereby obtaining toner 28. The temperature of the Henschel mixer was adjusted so that the temperature of the mixture was 30°C.

[0348] Matters regarding the manufacturing conditions of toner 28 are shown in Table 5.

[0349] [Table 5]

[0350] Toner No. Hot air temperature in spheroidization step 28 280℃ 29 235℃ 30 210℃

[0351] Example of production of toner 29 and 30

[0352] Except for changing the manufacturing conditions as shown in Table 5, toners 29 and 30 were obtained in the same manner as in the production example of toner 28.

[0353] Example of production of toner 31

[0354]

[0355] The formulation was mixed in a Henschel mixer (FM-75, Mitsui Miike), and then melt-kneaded in a twin-screw kneader (PCM-30, Ikegai) set at 120°C. The kneaded product was cooled and coarsely pulverized to 1 mm or less in a hammer mill, thereby obtaining a crushed product. The crushed product was pulverized twice with a mechanical pulverizer (T-250, Turbo Kogyo), thereby obtaining pulverized resin particles.

[0356] Spheroidization step

[0357] The pulverized resin particles were simultaneously spheroidized and classified in a mechanical surface modification apparatus (Faculty F-400, Hosokawa Micron) with a dispersing rotor rotating at 12,000 rpm and a classifying rotor rotating at 6,000 rpm, thereby obtaining toner particles 31.

[0358] 0.5 parts of hydrophobic silica particles having a number average particle diameter of 20 nm of primary particles surface-treated with 25 mass% hexamethyldisilazane were added to 100.0 parts of the toner particles 31, and mixed in a Henschel mixer (Mitsui Miike, FM-10), thereby obtaining toner 31. The temperature of the Henschel mixer was adjusted so that the temperature of the mixture was 30°C.

[0359] Matters regarding the manufacturing conditions of the toner 31 are shown in Table 6.

[0360] [Table 6]

[0361] Toner No. Dispersion rotor revolution number Fractionation rotor revolution number 31 12000 rpm 6000 rpm 32 6000 rpm 6000 rpm

[0362] Example of production of toner 32

[0363] The toner 32 was obtained in the same manner as in the production example of the toner 31 except that the manufacturing conditions were changed as shown in Table 6.

[0364] Example of production of toner 33

[0365] Preparation of water-based medium

[0366] To a granulation tank, 100.0 parts of deionized water, 2.0 parts of sodium phosphate, and 0.9 parts of hydrochloric acid having a concentration of 10 mass% of hydrogen chloride were added, and heated and maintained at 50°C. To this, 1.2 parts of an aqueous calcium chloride solution of calcium chloride hexahydrate in 8.2 parts of deionized water was added. After the addition, it was stirred with a TK homomixer (product name, Tokushu Kika) at a circumferential velocity of 25 m / s for 30 minutes, to thereby obtain a pH 5.0 aqueous solution containing the poorly water-soluble inorganic fine particles.

[0367] Preparation of polymerizable monomer composition

[0368] Preparation of dispersed pigment composition

[0369] Styrene 39.0 parts

[0370] Carbon black 6.5 parts

[0371] (Nipex 35, Evonik Japan)

[0372] These materials were introduced into a mill (Nippon Coke & Engineering), and stirred with zirconia beads having a radius of 1.25 mm at 25°C, 200 rpm for 180 minutes, and the zirconia beads were removed, to thereby prepare a dispersed pigment composition.

[0373] Preparation of polymerizable monomer composition

[0374] The following materials were put into the same container and mixed and dispersed with a TK homomixer (Tokushu Kika) at a circumferential velocity of 20 m / s.

[0375]

[0376] It was further heated to 60°C, 10.0 parts of behenyl behenoyl (melting point: temperature of the maximum endothermic peak: 72°C) was added, and the mixture was dispersed and mixed for 30 minutes, to thereby obtain a polymerizable monomer composition.

[0377] Step (I)

[0378] The polymerizable monomer composition was added to an aqueous medium containing the poorly water-soluble inorganic fine particles, and stirred with a TK homomixer (Tokushu Kika) at a circumferential velocity of 30 m / s at 60°C under a nitrogen atmosphere. 6.0 parts of a polymerization initiator, t-butyl peroxyneodecanoate (NOF Corp., product name "Perbutyl PV", molecular weight: 202, 10-hour half-life temperature: 53.2°C) was dissolved therein, to thereby prepare a polymerizable monomer composition containing a polymerization initiator.

[0379] Step (II)

[0380] The dispersion containing the particles of the polymerizable monomer composition was transferred to a tank and heated to 70°C under stirring with a paddle, and the polymerizable monomer contained in the particles of the polymerizable monomer composition was allowed to undergo a polymerization reaction for 6 hours. Then, it was further heated to 80°C and reacted for 6 hours to form resin particles. The pH of the polymer slurry at this time was 5.0. Then, aluminum chloride was added at 80°C to a concentration of 2.0 mmol / L and stirring was continued under the same conditions for 2 hours.

[0381] Distillation step

[0382] After the completion of the polymerization step, the supply of water vapor at 120°C to the slurry containing the aqueous medium and the resin particles was started at a flow rate of 30.0 parts / hour. After the start of the water vapor supply, distillation was started once the temperature reached 98°C and was carried out for 8 hours.

[0383] Step (III)

[0384] After the completion of the distillation step, a 7.0% aqueous sodium carbonate solution was added to the slurry containing the aqueous medium and the resin particles to change the pH of the aqueous medium to 8.0. Then, it was maintained at 80°C for 30 minutes.

[0385] Washing, filtration, drying and fractionation step

[0386] After the completion of Step (III), the mixture was cooled, adjusted to pH 1.4 with hydrochloric acid, and stirred for 2 hours, thereby obtaining an aqueous dispersion containing toner particles. The toner particles were filtered from the aqueous dispersion, water-washed, dried at 40°C for 48 hours, and classified, thereby obtaining toner particles 33.

[0387] External addition step

[0388] The external addition step was carried out in the same manner as in the production example of toner 1.

[0389] The physical properties of toners 1 to 33 are shown in Table 7.

[0390] [Table 7]

[0391]

[0392] Example 1

[0393] The following evaluations were carried out using toner 1. A commercially available color laser printer (HP Color LaserJet Enterprise M855) was modified for the evaluations. Four modifications were as follows.

[0394] (1) Modification so as to operate with only a single-color toner cartridge and an image drum installed.

[0395] (2) Modification of the processing speed to 55 ppm.

[0396] (3) The fixing unit is capable of changing any temperature.

[0397] (4) Modification of the gears around the developing roller and the toner supply roller portion of the image drum so that the rotation direction of the developing roller and the toner supply roller portion is switched from the same direction rotation to the opposite direction rotation.

[0398] The toner was taken out from the black toner cartridge and the image drum which had been installed to the color laser printer, the inside was cleaned by air purge, 425 g of toner 1 was introduced into the toner cartridge, and also 127 g of toner 1 was introduced into the image drum, the toner cartridge and the image drum filled with the toner were installed to the unit, and the following evaluation was performed. The specific image evaluation items were as follows.

[0399] Image fogging

[0400] A line image of 1% print rate was printed out for 30,000 sheets in a low temperature and low humidity environment (15°C, 10% RH) and a high temperature and high humidity environment (33°C, 85% RH), and left for 48 hours. Then, one more image was printed out, and the reflectance (%) of the non-image portion of the image was measured with "Reflectometer Model TC-6DS" (Tokyo Denshoku).

[0401] The obtained reflectance value was subtracted from the reflectance (%) measured in the same manner on the unused printed paper (plain paper), thereby obtaining the value (%) evaluated according to the following criteria. The smaller the value, the more the image fog is suppressed. The evaluation was performed in the glass paper mode using plain paper (HP Brochure Paper 200g, Glossy, HP Corp., 200 g / m 2

[0402] Evaluation Criteria

[0403] A: Less than 0.5%

[0404] B: 0.5% or more and less than 1.5%

[0405] C: 1.5% or more and less than 3.0%

[0406] D: 3.0% or more

[0407] Contamination of member

[0408] ​A halftone image was output in a high temperature and high humidity environment (33°C, 85% RH), and no unevenness in density on the image was confirmed. Then, 50,000 copies of a vertical line image with a print rate of 30% were output. In this evaluation, the cartridge whose capacity had been consumed during the test was replaced with a newly prepared toner cartridge.

[0409] After 50,000 copies were printed, a halftone image was output, and no unevenness in density between the printed image portion and the non-printed image portion of the halftone image was visually observed. Then, the developing blade was taken out, the toner at the contact portion between the developing roller and the developing blade was blown with air, and the developing blade was observed. The observed results were evaluated according to the following criteria.

[0410] Evaluation Criteria

[0411] A: No unevenness in density on the image, and the developing blade was good

[0412] B: No unevenness in density on the image, but some filming on the developing blade was confirmed.

[0413] C: Slight unevenness in density on the image

[0414] D: Severe unevenness in density on the image

[0415] Fine line reproducibility

[0416] Fine line reproducibility was evaluated in a normal temperature and humidity environment (25°C, 50% RH). 20,000 copies of a vertical line image with a print rate of 30% were printed, and then a grid pattern with a line width of 3 pixels was printed on the entire surface of an A4 sheet at a print area rate of 4%, and the fine line reproducibility was evaluated by the following criteria.

[0417] The line width of 3 pixels was 127 μm in theory. The line width of the actual image was measured with a microscope VK-8500 (product name, Keyence). The line width was measured at 5 arbitrarily selected points, and the average of the three points other than the minimum and maximum values was taken as d (μm), and the fine line reproducibility index L was calculated and evaluated according to the following criteria.

[0418] L (μm) = | 127 - d |

[0419] L is defined as the difference between the theoretical line width of 127 μm and the line width d on the output image. Since d can be greater than 127 or less than 127, the difference is defined as the absolute value. The smaller the value of L, the better the fine line reproducibility.

[0420] Evaluation Criteria

[0421] A: L was 0 μm or more and less than 5 μm.

[0422] B: L is 5 μm or more and less than 15 μm, and slight variation in line width is observed.

[0423] C: L is 15 μm or more and less than 30 μm, fine lines and scattering are observed, but are at an acceptable level for practical use.

[0424] D: L is 30 μm or more, and in some places, fine lines are broken or narrowed.

[0425] The results of Example 1 are shown in Table 8. As shown in Table 8, the results of Example 1 were all good.

[0426] Examples 2 to 12

[0427] Evaluation was performed by the method for evaluating toner 1 except that the toners shown in Table 8 were used instead of toner 1. The evaluation results are shown in Table 8.

[0428] Comparative examples 1 to 18

[0429] Evaluation was performed by the method for evaluating toner 1 except that the toners shown in Table 8 were used instead of toner 1. The evaluation results are shown in Table 8.

[0430] [Table 8]

[0431]

[0432] While the present application has been described with reference to exemplary embodiments, it is to be understood that the application is not limited to the disclosed exemplary embodiments. The scope of the following claims is meeting the widest interpretation so as to encompass all such modifications and equivalents.

Claims

1. A toner comprising toner particles, characterized in that, the toner particles contain a binder resin, the binder resin contains a resin A and a resin B, the toner particles include projections on their surfaces, the projections each contain the resin B, a shape factor SF-2 of the toner observed under a scanning electron microscope is 105 to 120, a shape factor SF-1 of the toner observed under a scanning electron microscope is 105 to 120, and a surface unevenness index of the toner calculated by the following formula (1) is 0.010 to 0.050 when the toner is observed under a scanning electron microscope: Surface unevenness index = (area of a region enclosed by a convex hull of a toner - projected area of a toner) / projected area of a toner (1), the resin A contains a styrene (meth) acrylic resin, and the resin B contains a polyester resin, a content of the polyester resin with respect to 100.0 parts by mass of the resin A is 3.0 to 15.0 parts by mass.

2. The toner according to claim 1, wherein a standard deviation of the surface unevenness index of the toner is 0.010 or less.

3. The toner according to claim 1 or 2, wherein an acid dissociation constant pKa of the polyester resin is less than 6.

5.

4. The toner according to claim 1 or 2, wherein an acid value of the resin B is 14 mgKOH / g or more and 20 mgKOH / g or less.

5. The toner according to claim 1 or 2, wherein the toner particles contain a wax, and in a toner cross section observed under a transmission electron microscope, when As is a percentage of the area occupied by the wax in a region defined by a contour of the toner and a line drawn 1.0 μm away from the contour toward the inside of the toner, and when Ac is a percentage of the area occupied by the wax in an inner region inward from the line drawn 1.0 μm away from the contour toward the inside of the toner, the As and Ac satisfy the following formula (2): 50.0 ≥ [As / (Ac+As)] x 100 ≥ 3.0 (2).

6. A method for producing a toner, the toner comprising toner particles, characterized in that, the toner particles contain a binder resin, the binder resin contains a resin A and a resin B, the toner particles include projections on their surfaces, the projections each contain the resin B, a shape factor SF-2 of the toner observed under a scanning electron microscope is 105 to 120, a shape factor SF-1 of the toner observed under a scanning electron microscope is 105 to 120, and a surface unevenness index of the toner calculated by the following formula (1) is 0.010 to 0.050 when the toner is observed under a scanning electron microscope, the method for producing comprises: a step (I) of forming particles of a polymerizable monomer composition containing the resin B and a polymerizable monomer for forming the resin A in an aqueous medium, Step (II) polymerizing the polymerizable monomer contained in the particles of the polymerizable monomer composition in the aqueous medium to form resin particles, and Step (III) keeping the resin particles in the aqueous medium having a pH higher than an acid dissociation constant pKa of the resin B at a temperature above a glass transition temperature of the resin B: Surface unevenness index = (area of a region surrounded by a convex hull of toner - projected area of toner) / projected area of toner (1), the resin A contains a styrene (meth)acrylic resin, and the resin B contains a polyester resin, the polyester resin is contained at 3.0 to 15.0 parts by mass relative to 100.0 parts by mass of polymerizable monomers used to form the resin A.

7. The method for producing a toner according to claim 6, wherein In the step (III), the resin particles are kept in the aqueous medium having a pH higher than an acid dissociation constant pKa of the resin B at a temperature above a glass transition temperature of the resin B for 30 minutes or more.

8. The method of producing a toner according to claim 6 or 7, wherein the acid value of the resin B is 10 mgKOH / g or more.

9. The method of producing a toner according to claim 6 or 7, wherein in the step (III), the pH of the aqueous medium is 6.5 to 10.0, and the acid dissociation constant pKa of the polyester resin is less than 6.5.

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