Toner cleaning agent, method for producing toner cleaning agent, and toner composition

Abstract

The present invention provides a toner cleaning agent, a method for producing the toner cleaning agent, and a toner composition containing the toner cleaning agent and a toner base particle, the toner cleaning agent can exhibit excellent cleaning properties, can impart appropriate fluidity to a toner, and can be used as a toner cleaning agent. And the wear of the cleaning blade can be inhibited even in a high-temperature and high-humidity environment. The toner cleaning agent is a divalent metal salt of a fatty acid obtained by metathesis of a divalent metal salt and a salt of a basic compound of a fatty acid having 8 to 24 carbon atoms, the divalent metal salt of the fatty acid having a water activity value A of 0.65 to 0.85 at 25 DEG C; in a projected image of a divalent metal salt of a fatty acid having an equivalent circle diameter in the range of cumulative 10% diameter-cumulative 90% diameter on a volume basis, the number average value (B) of the solidity defined by the ratio of the projected area to the convex hull area (projected area / convex hull area) is 0.910-0.990.

Description

Technical Field

[0001] The present invention relates to a cleaning agent for use in a toner for developing an electrostatic latent image (hereinafter simply referred to as "toner"), a method for producing the cleaning agent, and a toner composition containing the cleaning agent. Background Art

[0002] The toner used in an electrophotographic image forming device such as a copier or printer is a composite particle formed by coating the surface of a toner masterbatch composed of a thermoplastic resin such as a polyester resin or a styrene-acrylic resin as a binder resin with a colorant such as carbon black, magnetic powder, pigment, a charge control agent, paraffin, etc.

[0003] Conventionally, in an electrophotographic image forming apparatus, a cleaning agent is supplied to the surface of an electrophotographic photoreceptor (hereinafter referred to simply as a "photoreceptor") to reduce friction with a blade (hereinafter referred to simply as a "cleaning blade") used to clean the surface of the photoreceptor, thereby preventing colorant from seeping out and thereby inhibiting film formation or preventing wear on the surface of the photoreceptor.

[0004] Methods for supplying a cleaning agent to the surface of a photoreceptor include: (1) a method of using a cleaning agent coating system (applicator); (2) a method of adding the cleaning agent to a layer on the surface of the photoreceptor; (3) a method of adding and covering the cleaning agent to the colorant particles and supplying the cleaning agent to the surface of the photoreceptor while developing the colorant.

[0005] As a method of supplying using a detergent coating system as described above (1), there is a method of providing a coating device for coating the detergent on the surface of the photoreceptor. In this method, the advantage is that the detergent can be evenly supplied to the entire surface of the photoreceptor. However, a dedicated device is required, and a space is required to set up the coating device, etc., which cannot avoid the large-scale and complex image forming device. In addition, there is a problem of uneven coating of the detergent due to deterioration of the coating component, or there is a problem of requiring an additional detergent replenishing device, which makes maintenance complicated.

[0006] The method (2) of adding a cleaning agent to the layer on the surface of the photoreceptor has a certain effect of suppressing the surface wear of the photoreceptor. However, there is a problem that partial sensitivity characteristics decrease, resulting in partial deviations in the characteristics of the photoreceptor surface, resulting in image defects.

[0007] The method (3) of adding and covering the cleaning agent to the colorant particles and supplying it to the surface of the photosensitive body during development is adopted by most electronic photographic image forming devices because the device can be miniaturized and the cleaning agent can be easily supplied.

[0008] As the cleaning agent used in the method (3), fatty acid metal salts have been conventionally used, and studies have been conducted on the stability of blade cleaning and the suppression of uneven wear because of their good lubricity.

[0009] When transporting and delivering ink cartridges containing toner, especially in summer, they are sometimes exposed to high temperatures above 50°C. In addition, in recent years, due to the globalization of printers, multifunction machines, etc., in addition to high temperatures, there are also cases of continuous long-term use exposed to high humidity environments. Therefore, for fatty acid metal salts, the following properties are sought: even in the above environment, it is possible to properly disperse and adhere to the toner particles, to give the toner excellent fluidity, and to quickly detach the toner particles from the cleaning blade. In addition, with the increase in the speed of printing presses, a fatty acid metal salt that can further quickly detach the toner particles from the cleaning blade is sought.

[0010] For example, Patent Document 1 proposes the following technology, that is, adding a fatty acid metal salt with a volume average particle size of 3 to 15 μm as an external additive to the toner mother particle, and setting the ratio (B / A) of the number B of the fatty acid metal salt in a specified field of view to the content ratio (weight %) A of the fatty acid metal salt in the entire toner within a specified range. Patent Document 1 records that by externally adding a fatty acid metal salt with the above-mentioned specified particle size at the above-mentioned specified ratio (B / A), the cleaning property is improved, the wear of the photoreceptor surface caused by the friction of the cleaning blade is suppressed, and the charging characteristics of the toner are further stabilized, thereby forming a good image without image defects.

[0011] Patent Document 2 proposes a technique of using fatty acid metal salt particles having an iron content of 0.0008 mass % or more and 0.01 mass % or less as an external additive for a toner. Patent Document 2 states that by using fatty acid metal salt particles having an iron content within the above range, horizontal streaks are less likely to occur on the image forming surface of a storage medium even when images are repeatedly formed.

[0012] Patent Document 3 proposes a technique of using fatty acid metal salt particles containing sulfur in a range of 0.0035 mass % to 0.07 mass % as an external additive for toner. Patent Document 3 states that by using fatty acid metal salt particles having a sulfur content in the above range, wear of a blade for cleaning an image carrier can be suppressed.

[0013] Prior art literature

[0014] Patent Literature

[0015] Patent Document 1: Japanese Patent Application Publication No. 2000-089502

[0016] Patent Document 2: Japanese Patent Application Publication No. 2017-125928

[0017] Patent Document 3: Japanese Patent Application Publication No. 2016-218409 Summary of the invention

[0018] 1. Technical issues to be resolved

[0019] However, even if the techniques described in Patent Documents 1 to 3 are used, it is difficult to suppress the wear of the cleaning blade in a high-temperature and high-humidity environment.

[0020] The present invention has been completed in view of the above-mentioned technical problems, and its purpose is to provide a toner cleaning agent that can exert excellent cleaning properties, impart appropriate fluidity to the colorant, and suppress the wear of the cleaning blade even in a high-temperature and high-humidity environment, a method for producing the toner cleaning agent, and a toner composition containing the toner cleaning agent.

[0021] (II) Technical solution

[0022] The inventors of the present application conducted intensive studies to solve the above technical problems and found that divalent metal salts of fatty acids having a predetermined water activity value and area envelope degree exhibit excellent performance when used as a toner detergent, thereby completing the present invention.

[0023] That is, the toner detergent of the present invention is a divalent metal salt of a fatty acid obtained by double decomposition of a fatty acid alkaline compound salt and a divalent metal salt, wherein the fatty acid alkaline compound salt is obtained by reacting a monovalent alkaline compound with a fatty acid having 8 to 24 carbon atoms, and the toner detergent is characterized in that:

[0024] The divalent metal salt of the fatty acid has a water activity value A at 25° C. calculated by the following formula (1) of 0.65 to 0.85, and a number average value B of the solidity defined by the ratio of the projection area to the area inside the envelope (projection area / convex hull area) in the projection image of the divalent metal salt of the fatty acid with an equivalent circle diameter in the range of cumulative 10% diameter to cumulative 90% diameter on a volume basis is 0.910 to 0.990,

[0025] Formula (1)

[0026] A=P / P0

[0027] P: Water vapor pressure at 25°C in a sealed container containing a divalent metal salt of a fatty acid (Pa)

[0028] P0: Vapor pressure of water at 25°C (Pa).

[0029] The divalent metal salt of a fatty acid used as the toner detergent of the present invention preferably has a volume-based median particle size (D50) of 0.3 to 5.0 μm as measured by a laser diffraction scattering method.

[0030] In the divalent metal salt of a fatty acid used in the toner cleaning agent of the present invention, the divalent metal contained in the divalent metal salt of a fatty acid is preferably at least one selected from the group consisting of zinc, calcium, and magnesium.

[0031] The method for producing a toner detergent of the present invention is a method for producing the divalent metal salt of a fatty acid as the toner detergent of the present invention, characterized in that the method comprises the following steps:

[0032] A step of preparing a slurry of a divalent metal salt of a fatty acid by reacting a monovalent alkaline compound with a fatty acid having 8 to 24 carbon atoms and reacting the obtained fatty acid alkaline compound salt with a divalent metal salt in an aqueous solution through a double decomposition method;

[0033] A step of obtaining a water-containing cake of a divalent metal salt of a fatty acid from the slurry;

[0034] The step of drying the water-containing cake by hot air drying at a temperature not less than the melting point of the divalent metal salt of the fatty acid and not more than 200° C., thereby drying and crushing the water-containing cake.

[0035] The toner composition of the present invention is characterized by comprising the toner detergent of the present invention and toner mother particles, wherein the toner detergent is contained in a ratio of 0.01 to 5 parts by mass based on 100 parts by mass of the toner mother particles.

[0036] (III) Beneficial effects

[0037] The divalent metal salt of a fatty acid used as a cleaning agent for a toner of the present invention can exhibit excellent cleaning properties, impart appropriate fluidity to the toner, and suppress wear of a cleaning blade in a high temperature and high humidity environment, compared to a fatty acid metal salt having a water activity value A at 25° C. that is not within the range of 0.65 to 0.85 or a number average value B of solidity that is not within the range of 0.910 to 0.990. DETAILED DESCRIPTION

[0038] Hereinafter, embodiments of the present invention will be described. The toner cleaning agent and toner composition of the present invention will be described in order.

[0039] In addition, in the present invention, the numerical range specified by the symbol "~" includes the numerical values ​​at both ends (upper limit and lower limit) of the "~". For example, "10 to 30" means a range of 10 or more and 30 or less.

[0040] (1) Toner Cleaner

[0041] The toner detergent of the present invention is a divalent metal salt of a fatty acid obtained by double decomposition of a fatty acid alkaline compound salt and a divalent metal salt, wherein the fatty acid alkaline compound salt is obtained by reacting a monovalent alkaline compound with a fatty acid having 8 to 24 carbon atoms, and the toner detergent is characterized in that:

[0042] The divalent metal salt of the fatty acid has a water activity value A at 25° C. calculated by the following formula (1) of 0.65 to 0.85, and a number average value B of the solidity defined by the ratio of the projection area to the convex hull area (projection area / convex hull area) in the projection image of the divalent metal salt of the fatty acid with an equivalent circle diameter in the range of the cumulative 10% diameter to the cumulative 90% diameter on a volume basis is 0.910 to 0.990,

[0043] Formula (1)

[0044] A=P / P0

[0045] P: Water vapor pressure at 25°C in a sealed container containing a divalent metal salt of a fatty acid (Pa)

[0046] P0: Vapor pressure of water at 25°C (Pa).

[0047] In the past, it is known that there is a technology of adding fatty acid metal salts such as zinc stearate to colorant particles for use as a cleaning agent. The fatty acid metal salt is released from the colorant particles and transferred to the surface of the photoreceptor, and acts as a lubricant between the photoreceptor and the cleaning blade, thereby suppressing the wear of the cleaning blade. However, when forming an image using a colorant to which a fatty acid metal salt is externally added, sometimes during the progress of the wear of the cleaning blade, there is a deviation in the axial direction (the axial direction of the photoreceptor, i.e., the direction perpendicular to the driving direction of the driven photoreceptor) or the progress of the overall wear of the cleaning blade is faster than expected. The reasons are speculated as follows.

[0048] Fatty acid metal salt is a compound obtained by reacting in water, and it is inferred from its constituent materials that it contains a certain amount of water. By containing a certain amount of water, fatty acid metal salt is easily positively charged due to friction in the developing device. Therefore, in an image forming device using a negatively charged colorant, it is easy to transfer to the non-image part of the photoreceptor surface, and in an image forming device using a positively charged colorant, it is easy to transfer to the image part of the photoreceptor surface. Therefore, when the image forming device uses any one of the negatively charged colorant or the positively charged colorant, the distribution of the fatty acid metal salt will deviate along its axial direction on the photoreceptor surface. In addition, when the image forming device uses a positively charged colorant, the fatty acid metal salt is transferred to the transfer body together with the colorant particles, and the amount of fatty acid metal salt present on the photoreceptor surface becomes less than expected. Since fatty acid metal salts are easy to retain moisture in a high temperature and humid environment, these phenomena are further prone to occur.

[0049] If there is a deviation in the distribution of fatty acid metal salts on the photoreceptor surface, the cleaning blade is more likely to wear in the area where the fatty acid metal salts are less. In addition, if there is a deviation in the distribution of fatty acid metal salts along the axial direction on the photoreceptor surface, the cleaning blade will be distorted in the axial direction during contact with the photoreceptor surface, so that the cleaning blade is subjected to an unexpected load, which promotes the wear of the cleaning blade as a whole. In addition, when the amount of fatty acid metal salts originally present on the photoreceptor surface is less than expected, the cleaning blade is likely to wear more than expected.

[0050] For the above reasons, when forming an image using a toner to which a fatty acid metal salt is externally added, axial deviation occurs during the progress of wear of the cleaning blade, or the progress of wear of the entire cleaning blade is considered to be faster than expected.

[0051] In contrast, when the divalent metal salt of a fatty acid as the toner cleaning agent of the present invention is externally added to the toner and used as a cleaning agent, it can exhibit excellent cleaning properties, impart appropriate fluidity to the toner, and suppress wear of the cleaning blade even in a high temperature and high humidity environment.

[0052] The detailed mechanism is not yet clear, but it is speculated that the divalent metal salt of the fatty acid of the present invention having a water activity value A and a number average value B of the solidity (hereinafter sometimes simply referred to as "solidity B") within the above range can impart appropriate fluidity to the colorant and is not easily charged due to friction in a high temperature and high humidity environment. Therefore, when it is freed from the colorant particles and transferred to the surface of the photosensitive body, the distribution is not easily deviated and is evenly distributed in the axial direction of the entire photosensitive body, thereby performing the function of a lubricant between the cleaning blade and the cleaning blade, thereby suppressing the wear of the cleaning blade.

[0053] The toner detergent of the present invention is a divalent metal salt of a fatty acid having 8 to 24 carbon atoms. The divalent metal salt of a fatty acid is a fatty acid metal salt obtained by double decomposition of a basic compound salt of a fatty acid having 8 to 24 carbon atoms and a divalent metal salt. The divalent metal salt of a fatty acid having 8 to 24 carbon atoms can be prepared by a double decomposition method in which a basic compound salt of a fatty acid having 8 to 24 carbon atoms and a divalent metal salt are reacted in an aqueous solution.

[0054] The method for producing the toner cleaning agent of the present invention is not particularly limited, and examples thereof include a method comprising the following steps:

[0055] A step of preparing a slurry of a divalent metal salt of a fatty acid by reacting a monovalent alkaline compound with a fatty acid having 8 to 24 carbon atoms and reacting the obtained fatty acid alkaline compound salt with a divalent metal salt in an aqueous solution through a double decomposition method;

[0056] A step of obtaining a water-containing cake of a divalent metal salt of a fatty acid from the slurry;

[0057] The step of drying and crushing the water cake.

[0058] Hereinafter, each step included in the production method will be described, and then the physical properties of the divalent metal salt of a fatty acid as the toner detergent of the present invention will be described.

[0059] In addition, hereinafter, the divalent metal salt of a fatty acid serving as the toner cleaning agent of the present invention may be simply referred to as a "fatty acid metal salt".

[0060] (Preparation of Slurry of Fatty Acid Metal Salt)

[0061] The fatty acid metal salt slurry is prepared by a double decomposition method in which a monovalent basic compound is reacted with a fatty acid having 8 to 24 carbon atoms, and the obtained fatty acid basic compound salt is reacted with a divalent metal salt in an aqueous solution.

[0062] As the raw material of the fatty acid alkaline compound salt, there is no particular restriction as long as it is a fatty acid with 8 to 24 carbon atoms. That is, it can be any one of natural fatty acids and synthetic fatty acids, any one of saturated fatty acids and unsaturated fatty acids, and any one of straight-chain and branched fatty acids. Further, the structure of the fatty acid can contain functional groups such as hydroxyl, aldehyde, and epoxy groups. Preferably, the straight-chain saturated fatty acid with 12 to 22 carbon atoms is used, and more preferably, the straight-chain saturated fatty acid with 14 to 20 carbon atoms is used. When the carbon number is less than 8, the obtained fatty acid metal salt cannot obtain the effect as a fluidity improver. On the other hand, fatty acids with a carbon number greater than 24 are difficult to obtain industrially, and the solubility of the obtained fatty acid alkaline compound salt relative to water is significantly reduced, so the productivity decreases.

[0063] Examples of the fatty acid include caprylic acid, capric acid, lauric acid, myristic acid, myristic acid, palmitic acid, palmitoleic acid, stearic acid, oleic acid, linoleic acid, arachidic acid, behenic acid, erucic acid, hydroxystearic acid, and epoxystearic acid. Among them, stearic acid and myristic acid are preferred, and stearic acid is more preferred.

[0064] As the monovalent basic compound as the raw material of the fatty acid basic compound salt, there can be listed the hydroxides of alkali metals (sodium, potassium, etc.), and amines such as ammonia, monoethanolamine, diethanolamine, triethanolamine, etc. From the point of high solubility in water when making the fatty acid basic compound salt, the hydroxides of alkali metals such as sodium and potassium are preferred.

[0065] The fatty acid alkaline compound salt used in the present invention is usually obtained by reacting a monovalent alkaline compound with a fatty acid at a temperature above the melting point of the fatty acid and at a temperature at which the fatty acid does not decompose. The temperature is preferably 100° C. or less, more preferably 50 to 100° C., further preferably 60 to 90° C., and particularly preferably 70 to 85° C.

[0066] As the fatty acid alkaline compound salt used in the present invention, it is preferred that at least one is selected from the group consisting of sodium stearate, potassium stearate, sodium myristic acid and potassium myristic acid, more preferably at least one is selected from the group consisting of sodium stearate, potassium stearate and sodium myristic acid, and further preferably at least one is selected from sodium stearate and potassium stearate.

[0067] The divalent metal salt of a fatty acid used as the toner cleaning agent of the present invention is a fatty acid metal salt obtained by a double decomposition method in which the above-obtained basic fatty acid compound salt is reacted with a divalent metal salt in an aqueous solution.

[0068] Specifically, the divalent metal salt is a salt of a divalent inorganic metal and an inorganic acid or an organic acid.

[0069] Examples of the divalent inorganic metal include alkaline earth metals such as magnesium, calcium, and barium; and transition metals such as titanium, zinc, iron, manganese, cadmium, mercury, zirconium, lead, copper, cobalt, aluminum, and nickel. Among these metals, at least one selected from the group consisting of zinc, calcium, and magnesium is preferred, and zinc is more preferred, from the perspective of low environmental burden and easy industrial availability, as well as the cleanliness imparted by the obtained fatty acid metal salt.

[0070] Examples of the divalent metal salt include zinc chloride, zinc sulfate, calcium chloride, calcium acetate, magnesium chloride, magnesium sulfate, and aluminum sulfate. In particular, chlorides, sulfates, and nitrates of divalent metals such as zinc, calcium, and magnesium are preferred because they have high solubility in water and are easy and efficient to react with the fatty acid basic compound salt.

[0071] The above-mentioned reaction based on the double decomposition method can be carried out, for example, by separately preparing an aqueous solution containing a divalent metal salt and an aqueous solution containing a fatty acid alkaline compound salt, and then mixing them. Specifically, the aqueous solution containing a divalent metal salt and the aqueous solution containing a fatty acid alkaline compound salt are mixed by adding an aqueous solution containing a divalent metal salt to an aqueous solution containing a fatty acid alkaline compound salt or adding both in another reaction tank.

[0072] When the aqueous solution containing fatty acid alkaline compound salt is mixed with the aqueous solution containing divalent metal salt, for example, when slowly dripping the aqueous solution containing divalent metal salt in the aqueous solution containing fatty acid alkaline compound salt at an appropriate speed, there is the possibility that particles are easy to grow and particle diameter is easy to increase. Therefore, in the present invention, preferably in different containers, the aqueous solution containing fatty acid alkaline compound salt and the aqueous solution containing divalent metal salt are prepared respectively, and simultaneously put into another container to react and obtain. By adopting such a manufacture method, fatty acid metal salt with fine particle size can be obtained.

[0073] From the point of the particle diameter of the obtained fatty acid metal salt, the point of the productivity of the fatty acid metal salt and the point of the handleability of the aqueous solution containing fatty acid alkaline compound salt or the slurry of the obtained fatty acid metal salt, in the aqueous solution containing fatty acid alkaline compound salt used when preparing the slurry of fatty acid metal salt, the concentration of fatty acid alkaline compound salt is generally 1 mass %~10 mass %, and the lower limit is preferably more than 3 mass %, more preferably more than 5 mass %, and the upper limit is preferably less than 8 mass %. When the concentration of fatty acid alkaline compound salt is less than 1 mass %, there is the possibility that the productivity of fatty acid metal salt decreases, which is not preferred in practice. When greater than 10 mass %, due to the viscosity of the aqueous solution containing fatty acid alkaline compound salt or the slurry of the obtained fatty acid metal salt rising, it is sometimes difficult to react uniformly.

[0074] From the perspective of productivity of the fatty acid metal salt and handleability of the aqueous solution containing a divalent metal salt or the resulting slurry of the fatty acid metal salt, the concentration of the divalent metal salt in the aqueous solution containing a divalent metal salt used to prepare the slurry of the fatty acid metal salt is generally 0.1% by mass to 12% by mass, preferably 0.5% by mass to 10% by mass.

[0075] When the aqueous solution containing the fatty acid alkaline compound salt is mixed with the aqueous solution containing the divalent metal salt, it is preferred to adjust the addition amount of each aqueous solution in such a way that the equivalent ratio of the divalent metal salt to the fatty acid alkaline compound salt (divalent metal salt / fatty acid alkaline compound salt) is 1.80 to 2.00. If the above-mentioned equivalent ratio is within the above-mentioned range, the solidity B is high, that is, it is easy to obtain a fatty acid metal salt with a particle shape with less bumps. The lower limit of the above-mentioned equivalent ratio is more preferably 1.85 or more, and more preferably 1.90 or more, and the upper limit of the above-mentioned equivalent ratio is more preferably 1.99 or less, and more preferably 1.95 or less.

[0076] The liquid temperature during the reaction of the fatty acid alkaline compound salt and the divalent metal salt may be appropriately set according to the solubility of the fatty acid alkaline compound salt, and is not particularly limited, but is preferably 50 to 100° C., and more preferably 60 to 95° C. When the reaction temperature is lower than 50° C., there is a possibility that the reaction rate of the fatty acid alkaline compound salt and the divalent metal salt decreases.

[0077] When the fatty acid alkaline compound salt and the divalent metal salt are reacted, the polyalkylene glycol ether may be present in the aqueous solution, thereby stabilizing the obtained fatty acid metal salt slurry, thereby improving the productivity of the fatty acid metal salt.

[0078] As the polyalkylene glycol ether, triblock ether having a structure (EO-PO-EO) in which propylene oxide blocks are sandwiched between ethylene oxide blocks is particularly preferred.

[0079] The content of the polyalkylene glycol ether in the fatty acid metal salt slurry is usually 0.01 to 5 parts by mass, preferably 0.05 to 2 parts by mass, relative to 100 parts by mass of the fatty acid basic compound salt.

[0080] The polyalkylene glycol ether may be present in the reaction system before reacting the monovalent basic compound with the fatty acid, or may be present in the reaction system before reacting the fatty acid basic compound salt with the divalent metal salt.

[0081] (Preparation of a water-containing cake of a fatty acid metal salt)

[0082] The above method can obtain a slurry of a fatty acid metal salt. From the slurry of the fatty acid metal salt, a water-containing cake of the fatty acid metal salt is obtained. The water-containing cake of the fatty acid metal salt can be obtained, for example, by directly filtering the slurry of the fatty acid metal salt, or by separating the solvent using a centrifugal dehydrator, a filter press, a vacuum rotary filter, etc. Before obtaining the water-containing cake of the fatty acid metal salt, it can be washed as needed to remove the inorganic salts generated by the side reaction.

[0083] The water content of the water-containing cake of the fatty acid metal salt is not particularly limited, but is generally 30 to 60% by mass. The water content of the water-containing cake can be measured by the same method as that for measuring the water content of the fatty acid metal salt described below.

[0084] (Drying and crushing)

[0085] The fatty acid metal salt as the toner detergent of the present invention can be obtained by drying and crushing the water-containing cake of the fatty acid metal salt using an appropriate device.

[0086] In the past, as a drying method for obtaining a powder of a fatty acid metal salt, rack drying or airflow drying at about 100 to 150° C. was generally used. On the other hand, in the present invention, from the perspective of adjusting the water activity value A and the solidity B of the obtained fatty acid metal salt to a specified value, it is preferred to dry and crush the above-mentioned water-containing cake by hot air drying the above-mentioned water-containing cake. By hot air drying the water-containing cake in a high-temperature and high-speed airflow, the drying and crushing of the water-containing cake can be performed simultaneously. Such hot air drying can be performed, for example, using an airflow dryer that can be dried instantly with a high-temperature hot air flow. As a preferred airflow dryer, for example, a rapid flow dryer (model: FJD-4) manufactured by SEISHIN ENTERPRISE Co., Ltd. can be cited.

[0087] In the present invention, it is preferred to adjust the particle size distribution of the fatty acid metal salt by classifying the fatty acid metal salt obtained by drying and crushing the water-containing cake of the fatty acid metal salt. As a classification method, a known method can be used, without particular limitation. For example, a vibration sieve device that is vibrated and screened can be used for classification. In this way, a fatty acid metal salt as a toner cleaning agent of the present invention can be obtained.

[0088] In addition, the drying temperature of the hot air drying is preferably above the melting point of the fatty acid metal salt and below 200°C. When the drying temperature is lower than the melting point of the fatty acid metal salt, the water activity value A of the obtained fatty acid metal salt may become too high. In addition, when the drying temperature is higher than 200°C, the solidity B of the fatty acid metal salt may become too low due to softening of the fatty acid metal salt due to the treatment time.

[0089] In addition, the melting point of zinc stearate is 125°C, the melting point of zinc myristate is 130°C, the melting point of calcium stearate is 145°C, and the melting point of magnesium stearate is 122°C.

[0090] For each 1 kg of the water-containing cake of the fatty acid metal salt, the treatment time of the hot air drying is preferably within 0.1 hour / kg, more preferably within 0.08 hour / kg, and further preferably within 0.05 hour / kg. If the treatment time is greater than 0.1 hour / kg, the water activity value A of the obtained fatty acid metal salt may become too high, or the solidity B may become too low. In addition, the treatment time of the hot air drying is preferably greater than 0.02 hour / kg. If the treatment time of the hot air drying is less than 0.02 hour / kg, the water activity value A or the solidity B of the obtained fatty acid metal salt may become too low.

[0091] (physical properties)

[0092] The fatty acid metal salt used as the toner detergent of the present invention has a water activity value A at 25° C. of 0.65 to 0.85.

[0093] The water activity value A of fatty acid metal salt refers to the proportion of free water in the total water content contained in fatty acid metal salt, and is defined as the ratio of the water vapor pressure in a closed container containing a certain mass of fatty acid metal salt to the vapor pressure at that temperature. In addition, water can be classified into bound water, adsorbed water, and free water. Compared with bound water that is firmly bound to the constituent components of fatty acid metal salt, adsorbed water is water adsorbed on the surface of particles, and free water refers to water present near particles, which is transferred or evaporated due to the influence of temperature or humidity.

[0094] The water activity value A of the fatty acid metal salt at 25°C can be calculated by the following formula (1).

[0095] Formula (1)

[0096] A=P / P0

[0097] P: Water vapor pressure at 25°C in a sealed container containing a divalent metal salt of a fatty acid (Pa)

[0098] P0: Vapor pressure of water at 25°C (Pa)

[0099] The water activity value A can be easily measured using a known method, and can be measured using a water activity measuring device such as AquaLab4TE (manufactured by METER Group, Inc. (formerly Decagon Devices, Inc.)).

[0100] The fatty acid metal salt as the toner cleaning agent of the present invention may have a water activity value A at 25° C. of 0.65 to 0.85, and preferably 0.69 to 0.83 from the viewpoint of further suppressing the wear of the cleaning blade.

[0101] In addition, on a volume basis, the number average B of the solidity defined by the ratio of the projection area to the convex hull area (projection area / convex hull area) in the projected image of the fatty acid metal salt whose equivalent circle diameter is in the range of the cumulative 10% diameter to the cumulative 90% diameter is 0.910~0.990.

[0102] "Solidity" is an index that represents the degree of concavity and convexity of an object surface in a range of 0 to 1. The solidity is the value of the convex hull area, which is the area of ​​the projected image of the object divided by the area of ​​the projected image of the convex hull that buries the concavities on the object surface. The more complex the concavity and convexity on the object surface, the smaller the solidity value becomes. Therefore, particles with a solidity below a certain value can be judged as agglomerated particles formed by the adhesion of multiple particles.

[0103] The solidity can be measured by analyzing the projected image of the particles using a fully automatic image-based particle size distribution measuring device. For example, the equivalent circle diameter, projected area, and convex hull area can be measured in a dry dispersion using a fully automatic image-based particle size distribution measuring device "Morphologi 4" manufactured by Malvern Panalytical Ltd. to calculate the solidity.

[0104] More specifically, from the total particle group measured, particles whose equivalent circle diameters are between the cumulative 10% diameter and the cumulative 90% diameter based on volume are extracted, and for the extracted particles, the average number B of the solidity defined by the ratio of the projected area to the convex hull area (projected area / convex hull area) is calculated.

[0105] In the fatty acid metal salt as the toner cleaning agent of the present invention, the number average value B of the solidity may be 0.910 to 0.990, and the number average value B of the solidity is preferably 0.920 to 0.990 from the viewpoint of further suppressing the wear of the cleaning blade.

[0106] The median particle size (D50) of the fatty acid metal salt used as the toner cleaning agent of the present invention, measured by laser diffraction scattering method, is preferably 0.1 μm or more, more preferably 0.3 μm or more, and on the other hand, is preferably 5.0 μm or less, more preferably 3.0 μm or less, and further preferably 2.0 μm or less. If the fatty acid metal salt agglomerates, it is difficult for the fatty acid metal salt to be dispersed and attached to the toner particles. The fatty acid metal salt with a D50 of more than the above lower limit is not easy to agglomerate, so it is easy to be dispersed and attached to the toner particles. In addition, if the fatty acid metal salt is coarsened, the fatty acid metal salt is unevenly attached to the toner particles, but since the frequency of coarse particles of the fatty acid metal salt with a D50 of less than the above upper limit is low, it is easy to be uniformly attached to the toner particles.

[0107] The water content of the fatty acid metal salt used as the toner detergent of the present invention is preferably 8% by mass or less, and more preferably 6% by mass or less, from the viewpoint of dispersibility in the toner.

[0108] The water content can be measured by the loss on drying method in accordance with Japanese Industrial Standard JIS K0068.

[0109] (2) Toner composition

[0110] The toner composition of the present invention is characterized by comprising the toner detergent of the present invention and toner mother particles, wherein the toner detergent is contained in a ratio of 0.01 to 5 parts by mass based on 100 parts by mass of the toner mother particles.

[0111] In the toner composition of the present invention, the above-mentioned toner detergent of the present invention can be added by utilizing a conventional toner manufacturing method, for example, the toner detergent of the present invention can be externally added to known toner particles. Typically, the toner composition of the present invention is a composition in which the detergent of the present invention is externally added to the surface of the toner master particle, and an external additive different from the detergent is externally added as needed. When the toner composition is used, the detergent of the present invention can be released from the toner particles. In addition, in the present invention, "toner master particles" refer to colored resin particles containing a binding resin and a colorant, etc., and particles formed by adding external additives or detergents, etc. to the surface of the toner master particles are sometimes referred to as "toner particles".

[0112] Adding the detergent of the present invention to the toner master particles can be carried out by a conventionally known external addition treatment method, without particular limitation. Specifically, for example, the external additive and the detergent are added to the toner master particles together, and stirred using a stirrer or the like, so that the external additive and the detergent can be attached or adhered to the surface of the toner master particles.

[0113] As the stirrer, any conventionally known stirrer can be used without limitation. Specifically, for example, a common stirrer such as a turbine stirrer, a Henschel mixer, and a high-speed mixer can be mentioned, and a Henschel mixer can be used appropriately.

[0114] The content (addition amount) of the toner detergent of the present invention in the toner composition of the present invention is 0.01 to 5 parts by mass relative to 100 parts by mass of the toner master particles. By making the content of the toner detergent of the present invention within the above range, a toner composition can be provided that provides excellent fluidity to the toner while suppressing the wear of the cleaning blade in a high temperature and high humidity environment. The content of the toner detergent of the present invention is preferably 0.03 to 4 parts by mass, and more preferably 0.05 to 3 parts by mass relative to 100 parts by mass of the toner master particles.

[0115] The toner base particles contained in the toner composition of the present invention are not particularly limited, and may contain, for example, a binder resin (also referred to as a binder resin), a colorant, a charge control agent, a release agent, and the like.

[0116] Specific examples of the binder resin, the colorant, the charge control agent, the release agent, and the external additive are as follows, and known materials can be used as appropriate.

[0117] (Binder resin)

[0118] As the binder resin, polyester resin, styrene-(meth) acrylic copolymer resin, thermoplastic elastomer, styrene resin, (meth) acrylic resin, olefin resin (for example, α-olefin resins such as polyethylene and polypropylene, etc.), vinyl resin (for example, polyvinyl chloride, polyvinylidene chloride, etc.), polyamide resin, polyether resin, carbamate resin, epoxy resin, polyphenylene ether resin, terpene phenol resin, polylactic acid resin, hydrogenated rosin, cyclized rubber, cycloolefin copolymer resin, etc. can be listed. These components can be used alone or in combination of two or more. Among these components, polyester resin and styrene-(meth) acrylic copolymer resin are preferably used from the perspective of being able to further well-balance the image quality characteristics, durability, productivity, etc. of the toner.

[0119] (Colorant)

[0120] The colorant may be a pigment or dye of black, magenta, cyan, yellow or other colors.

[0121] Examples of the black colorant include carbon black such as lamp black, thermal black, acetylene black, channel black, furnace black, and aniline black dyes.

[0122] Examples of the magenta coloring agent include rose Bengal, Dupont Oil Red, CI Pigment Red 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 21, 22, 23, 30, 31, 32, 37, 38, 39, 40, 41, 48, 49, 50, 51, 52, 53, 54, 55, 57, 58, 60, 63, 64, 68, 81, 83, 87, 88, 89, 90, 112, 114, 122, 123, 163, 202, 206, 207, and 209; and CI Pigment Violet 1, 2, 10, 13, 15, 19, 23, 29, and 35.

[0123] Examples of the cyan colorant include aniline blue, calco oil blue, ultramarine blue, methylene blue chloride, phthalocyanine blue, CI Pigment Blue 2, 3, 15, 16, and 17; CI Vat Blue 6; and CI Acid Blue 45.

[0124] Examples of the yellow colorant include chrome yellow, quinoline yellow, and CI Pigment Yellow 1, 2, 3, 4, 5, 6, 7, 10, 11, 12, 13, 14, 15, 16, 17, 23, 65, 73, 74, 83, 93, 97, 128, 155, and 180.

[0125] These colorants can be used alone or in combination of two or more.

[0126] In particular, they are preferred for full color use due to their good color mixing properties and excellent color reproducibility: CI Pigment Red 57 and 122 are listed as magenta colorants, CI Pigment Blue 15 is listed as cyan colorants, and CI Pigment Yellow 17, 93, 155, and 180 are listed as yellow colorants.

[0127] (Charge Control Agent)

[0128] As the charge control agent, a positively chargeable or negatively chargeable charge control agent generally used to improve the chargeability of a toner can be appropriately selected and used without particular limitation.

[0129] As positively charged charge control agents, for example, modified products made of aniline black; quaternary ammonium salts such as tributylbenzylammonium-1-hydroxy-4-naphthalenesulfonate and tetrabutylammonium tetrafluoroborate; diorganic tin oxides such as dibutyltin oxide, dioctyltin oxide, and dicyclohexyltin oxide; diorganic tin borates such as dibutyltin borate, dioctyltin borate, and dicyclohexyltin borate; pyridinium salts, pyridine, triphenylmethane compounds, and low molecular weight polymers having cationic functional groups. These positively charged charge control agents can be used alone or in combination of two or more.

[0130] Among these positively chargeable charge control agents, nigrosine compounds and quaternary ammonium salts are preferably used.

[0131] As negatively charged charge control agents, for example, acetylacetone metal complexes, monoazo metal complexes, metal complexes or salts of naphthoic acid or salicylic acid, chelate compounds, low molecular weight polymers having anionic functional groups, etc. These negatively charged charge control agents can be used alone or in combination of two or more.

[0132] Among these negatively chargeable charge control agents, salicylic acid-based metal complexes and monoazo metal complexes are preferably used.

[0133] The content of the charge control agent is usually 0.1 to 5.0 parts by mass, preferably 0.5 to 3.0 parts by mass, relative to 100 parts by mass of the binder resin.

[0134] (Release Agent)

[0135] As the release agent, a release agent generally used as a release agent for toner can be appropriately selected and used, and there is no particular limitation. As the release agent, for example, ester waxes such as stearyl stearate, stearyl behenate, behenyl stearate, behenyl behenate, stearyl montanate, behenyl montanate, palmityl arachidate, pentaerythritol tetrapalmitate, pentaerythritol tetrastearate, pentaerythritol tetrabehenate, dipentaerythritol hexastearate, and dipentaerythritol hexabehenate can be cited; and hydrocarbon waxes such as polyethylene wax, polypropylene wax, Fischer-Tropsch wax, paraffin wax, microcrystalline wax, and petroleum wax can be cited.

[0136] These release agents can be used alone or in combination of two or more.

[0137] (External additives (fluidity improvers))

[0138] The colorant composition of the present invention may further contain an external additive different from the above-mentioned colorant detergent of the present invention as needed. The external additive is not particularly limited as long as it can be used as an external additive for the colorant. Specifically, for example, metal oxide particles such as silica particles, titanium oxide particles, aluminum oxide particles, zinc oxide particles and magnetite particles; resin particles; and resin particles surface-treated with the metal oxide particles or metal soap particles, etc. These external additives may be used alone or in combination of two or more. Among these external additives, silica particles are preferred from the point of view of excellent fluidity, charging properties, and polishing properties. In addition, the above-mentioned external additives may be externally added to the above-mentioned colorant masterbatch together with the above-mentioned colorant detergent of the present invention.

[0139] Example

[0140] Hereinafter, the present invention will be described in further detail with reference to Examples and Comparative Examples.

[0141] (Examples 1 to 5, Comparative Examples 1 to 5)

[0142] (1) Preparation of toner cleaning agents A-1 to A-5 and B-1 to B-5

[0143] (1-1) Preparation of fatty acid metal salt slurry

[0144] The raw material (a) of the divalent metal salt and the raw material (b) of the fatty acid alkaline compound salt shown in Table 1 were selected according to Table 2, and dissolved in water to prepare the component (a) of the aqueous solution of the raw material (a) and the component (b) of the aqueous solution of the raw material (b). The concentration of the raw material (a) in the component (a) and the concentration of the raw material (b) in the component (b) are shown in Table 2.

[0145] Next, the above-mentioned (a) component and (b) component are mixed by the following method at the liquid temperature shown in Table 2 so that the slurry amount of the obtained fatty acid metal salt is 500 kg, and a slurry of fatty acid metal salt (divalent metal salt of fatty acid) is obtained by a double decomposition method in which the raw materials (a) and (b) are reacted in an aqueous solution.

[0146] <Method for mixing components (a) and (b)>

[0147] Prepare a continuous homogenizer that can be supplied with mixed (a) components and (b) components by a metering pump, and a 600-liter receiving container with a stirring device having a turbine blade with a diameter of 30 cm, and rotate the turbine blade at 350 rpm. In order to make the equivalent ratio (a / b) of the divalent metal salt in the (a) component to the fatty acid alkaline compound salt in the (b) component be the value shown in Table 2, the (a) component and the (b) component adjusted to the liquid temperature shown in Table 2 are respectively supplied to the continuous homogenizer, so that they are discharged from the continuous homogenizer, and put into the receiving container to prepare a mixed solution. The flow rate of each solution is adjusted by a metering pump so that each solution ends the liquid feeding at the same time. After the total amount of loading is completed, the reaction is terminated by aging for 10 minutes while maintaining the liquid temperature, thereby obtaining a slurry of fatty acid metal salt.

[0148] (1-2) Preparation of water-containing cake of fatty acid metal salt

[0149] The slurry of the fatty acid metal salt obtained in the above manner is filtered, and the obtained fatty acid metal salt cake is washed twice with water to obtain a fatty acid metal salt water cake having a water content of 30 to 60% by mass.

[0150] (1-3) Drying and crushing

[0151] The aqueous cake of the fatty acid metal salt obtained above was dried with hot air using a rapid current dryer (model: FJD-4) manufactured by SEISHIN ENTERPRISE Co., Ltd. under the drying conditions shown in Table 2 (air flow temperature, treatment time per 1 kg of aqueous cake of fatty acid metal salt), thereby drying and crushing the aqueous cake. Furthermore, the cake was classified using a vibrating sieve device with a mesh size of 760 μm, thereby obtaining a fatty acid metal salt as a cleaning agent for a toner.

[0152] [Table 1]

[0153] Table 1

[0154]

[0155] [Table 2]

[0156]

[0157] The fatty acid metal salts (toner detergents) A-1 to A-5 and B-1 to B-5 obtained in the respective Examples and Comparative Examples were measured in the following manner.

[0158] (Water activity value A)

[0159] The fatty acid metal salt is placed in a sealed container at a constant temperature of 25°C, and the water activity value A is calculated using the following formula (1) based on the water vapor pressure in the container when the moisture on the particle surface and the surrounding air reaches a state of equilibrium and the water vapor pressure of pure water under the same conditions.

[0160] Formula (1)

[0161] A=P / P0

[0162] P: Water vapor pressure at 25°C in a sealed container containing a divalent metal salt of a fatty acid (Pa)

[0163] P0: Vapor pressure of water at 25°C (Pa)

[0164] Specifically, 10 g of fatty acid metal salt was added to a sample cup (outer diameter 40 mm, inner diameter 39.4 mm, height 11.4 mm, capacity 15 mL, made of high-density polyethylene), and placed in the measurement chamber of AquaLab 4TE (manufactured by METER Group, Inc. (formerly Decagon Devices, Inc.)), and the water activity value A at 25°C calculated using the above formula (1) was measured. In addition, the relative humidity in the chamber when measuring the water activity value A was 50% RH.

[0165] (Average value of solidity B)

[0166] Use 3mm 3 The fatty acid metal salt was used as the measurement sample. The fully automatic image-based particle size distribution measuring device "Morphologi 4" (manufactured by Malvern Panalytical Ltd.) was used to measure in a dry dispersion system using 10x and 50x objective lenses. From the total particle group measured, particles whose equivalent circle diameters were in the range of cumulative 10% diameter to cumulative 90% diameter on a volume basis were extracted. For each extracted particle, the solidity defined by the ratio of the projected area to the convex hull area (projected area / convex hull area) was calculated, and the number average was calculated based on these respective solidities, thereby calculating the number average B of the solidity.

[0167] (Water content (mass %))

[0168] The water content remaining in the fatty acid metal salt was determined according to the drying loss method of Japanese Industrial Standard JIS K0068. Specifically, 3 g of fatty acid metal salt was weighed in a precisely weighed weighing bottle, and the weighing bottle was accurately weighed again, and then left to stand in a dryer set at 105±2°C for 3 hours to dry it. Then, it was cooled in the dryer for 60 minutes, and then the weighing bottle was accurately weighed, and the weight loss ratio was calculated as the water content (mass %).

[0169] (Median particle size (D50) (μm))

[0170] To 0.05 g of the fatty acid metal salt, 40 ml of purified water and 0.001 g of polyoxyethylene nonylphenyl ether (NONION NS-210 manufactured by NOF CORPORATION) were added, and the mixture was dispersed for 10 minutes using an ultrasonic disperser to prepare a dispersion for measurement.

[0171] Next, the dispersion obtained for measurement was added to a laser diffraction particle size measuring device MICROTRAC MT3200II manufactured by NIKKISO CO., LTD., which circulates water as a circulating liquid, and the particle size distribution of the fatty acid metal salt was measured. Based on the measured value obtained as the volume distribution, the particle diameter at the time of 50% accumulation on a volume basis was calculated as the median particle size (D50). In addition, in this embodiment, the laser diffraction particle size measuring device MICROTRAC MT3200II manufactured by NIKKISO CO., LTD. was used for measurement, but a measuring device having the same function as MT3200II may also be used.

[0172] [Table 3]

[0173]

[0174] (2) Preparation of Toner Compositions C-1 to C10

[0175] 90.5 parts by mass of polyester resin (product name: Diacron ER-508, manufactured by Mitsubishi Chemical Corporation), 4.5 parts by mass of behenyl behenate (UNISTER M-2222SL of NOFCORPORATION), and 4.5 parts by mass of pigment yellow 180 (product name: TONER YELLOW HG, manufactured by Clariant) were mixed using a Henschel mixer to obtain a mixture. The mixture was melt-kneaded at 130° C. using a twin-screw kneading extruder to obtain a kneaded product. The kneaded product was slowly cooled to room temperature, coarsely pulverized using a cutting mill, further pulverized using a micro-powder grinder using a jet airflow, and further classified using a wind classifier to obtain a toner masterbatch as yellow colored particles.

[0176] 2.5 parts by mass of hydrophobic silica particles (RY50 manufactured by NIPPON AEROSIL CO., LTD.) and 0.1 parts by mass of the components shown in Table 4 of toner cleaning agents A-1 to A-5 and B-1 to B-5 were added to 100 parts by mass of the toner masterbatch, and mixed at a peripheral speed of 30 m / s for 3 minutes using a Henschel mixer. Then, the mixture was classified using a vibrating sieve device with a mesh size of 45 μm to obtain a toner composition (externally added toner).

[0177] (Liquidity Evaluation)

[0178] The fluidity was evaluated based on the difference angle of the toner composition obtained by measuring using a Powder tester model PT-X manufactured by Hosokawa Micron Corporation.

[0179] The difference angle of the toner composition is measured in the following manner according to the method proposed by Carr described in Carr, RL, Chem. Eng., January 18, 1965, Vol. 72.

[0180] As a measuring apparatus, a Powder tester model PT-X (manufactured by Hosokawa Micron Corporation) equipped with a numerically controlled vibration meter was used.

[0181] The toner composition that has passed through a 710 μm sieve is freely dropped from a certain height onto a circular sample stand to form a conical mountain of the toner composition. The angle of the hypotenuse of the conical mountain is measured as the angle of repose.

[0182] Next, the circular sample stand was tapped up and down three times under certain conditions, and the angle of the oblique side of the conical mountain after the conical mountain of the toner composition was collapsed was measured as the collapse angle.

[0183] The difference angle is calculated by the following formula using the repose angle and collapse angle measured as described above.

[0184] Difference angle (°) = repose angle (°) - collapse angle (°)

[0185] The collapse angle refers to the angle between the generatrix of the cone and the horizontal plane when a part of the cone collapses due to a prescribed impact on the conical mountain used in the determination of the angle of repose. The smaller the collapse angle, the easier it is for the powder to flow naturally. In addition, when no collapse occurs even after the prescribed impact, the angle of repose and the collapse angle are the same angle. In addition, the difference angle refers to the angle of the difference between the angle of repose and the collapse angle. The larger the difference angle, the higher the jetting property of the powder. In addition, when the angle of repose and the collapse angle are the same angle, the difference angle is 0°.

[0186] The difference between the angle of repose and the angle of collapse of the toner compositions C-1 to C-5 using the toner cleaning agents A-1 to A-5 of the present invention is 17° to 19°, so they have excellent cleanliness and do not have problems such as toner scattering. Among them, the toner compositions C-1 and C-2 with a difference angle in the range of 18° to 19° have particularly excellent cleanliness. In addition, if the difference angle is greater than 19°, the jetting property is too strong, resulting in problems such as toner scattering. In addition, when the difference angle is less than 17°, the fluidity of the toner deteriorates significantly and the cleanliness is poor. Therefore, the fluidity of the toner composition is determined in the following manner based on the difference angle.

[0187] <Liquidity Judgment Criteria>

[0188] A: The difference angle is 18° or more and 19° or less

[0189] B: The difference angle is greater than 17° and less than 18°

[0190] F: The difference angle is less than 17° or greater than 19°

[0191] (Wear cross-sectional area in high temperature and high humidity environment)

[0192] A commercially available color printer was prepared, and the above toner composition (negatively charged) was placed in a developing device. Using the image forming device, 1,000 images with an image density of 5% were printed in a high temperature and high humidity environment (temperature 30° C., relative humidity 85%).

[0193] In the image formation of this example, the axial center of the photoreceptor is the image portion, and the position 10 cm away from the axial center of the photoreceptor is the non-image portion.

[0194] Before and after the image was formed, the cross-sectional profile of the cleaning blade of the photoreceptor was observed using a laser microscope (manufactured by KEYENCE CORPORATION, VK-9500). The cross-sectional profile was observed at two locations, the center of the axial direction of the cleaning blade (image portion) and a position 10 cm away from the center of the axial direction (non-image portion), with an axial length of 80 μm. The difference in cross-sectional area before and after the image was formed was calculated for each of the two locations and was taken as the wear cross-sectional area (μm 2 ). The above-mentioned “axial direction of the cleaning blade” refers to the same direction as the axial direction of the photoreceptor.

[0195] The smaller the wear cross-sectional area, the better the effect of suppressing the wear of the cleaning blade. Therefore, the wear suppression effect of the cleaning blade is determined based on the wear cross-sectional area in the following manner.

[0196] <Wear suppression effect evaluation criteria>

[0197] A: Wear cross-sectional area is 20 μm 2 the following

[0198] B: Wear cross-sectional area greater than 20 μm 2 and 40μm 2 the following

[0199] F: Wear cross-sectional area greater than 40 μm 2

[0200] [Table 4]

[0201]

[0202] The toner compositions C-1 to C-5 prepared in Examples 1 to 5 are compositions containing toner cleaning agents A-1 to A-5, so there is no problem of toner scattering, and they can exert excellent cleaning properties and have appropriate fluidity. Furthermore, it is not easy to cause abrasion of the cleaning blade in a high temperature and high humidity environment. The toner cleaning agents A-1 to A-5 are divalent metal salts of fatty acids obtained by double decomposition of alkaline compound salts of fatty acids having 8 to 24 carbon atoms and divalent metal salts, and the water activity value A is 0.65 to 0.85, and the solidity B is 0.910 to 0.990. Among them, the toner compositions C-1 to C-3 of Examples 1 to 3 are particularly not easy to cause abrasion of the cleaning blade in a high temperature and high humidity environment. This is presumably because the water activity value A of the toner cleaning agents A-1 to A-3 contained in the toner compositions C-1 to C-3 is in a more preferred range of 0.69 to 0.83, and the solidity B is in a more preferred range of 0.920 to 0.990. Furthermore, the toner compositions C-1 to C-2 of Examples 1 to 2 have particularly excellent fluidity. This is presumably because the water activity value A and the solidity B of the toner cleaning agents A-1 to A-2 contained in the toner compositions C-1 to C-2 are well balanced.

[0203] In Examples 1 to 5, when preparing fatty acid metal salts (cleaning agents for toners), fatty acid alkaline compound salts having carbon atoms of 8 to 24 and divalent metal salts were used as raw materials, and the drying conditions when the water-containing cake of fatty acid metal salt obtained from the slurry was subjected to high-temperature hot air drying were further adjusted, thereby making the water activity value A of the obtained fatty acid metal salt 0.65 to 0.85 and the solidity B 0.910 to 0.990. In the past, the drying of fatty acid metal salts used as cleaning agents or external additives for toners was usually carried out under conditions similar to those of Comparative Example 2.

[0204] On the other hand, although the solidity B of the toner cleaning agent B-1 used in the toner composition C-6 prepared in Comparative Example 1 is in the range of 0.910 to 0.990, the water activity value A is less than 0.65, so the fluidity is too low and the cleaning property is poor, and the cleaning blade is easily worn in a high temperature and humid environment.

[0205] As for the toner compositions C-7 and C-9 prepared in Comparative Examples 2 and 4, although the solidity B of the toner cleaning agents B-2 and B-4 used therein is in the range of 0.910 to 0.990, the water activity value A is greater than 0.85, so its fluidity is too low and the cleaning property is poor, and the cleaning blade is easily worn in a high temperature and humid environment.

[0206] The colorant composition C-8 prepared in Comparative Example 3 uses a colorant cleaning agent B-3 whose water activity value A is less than 0.65 and whose solidity B is less than 0.910. Therefore, the jetting property is too strong, which may cause problems such as colorant scattering and the cleaning blade may be easily worn in a high temperature and high humidity environment.

[0207] As the toner composition C-10 prepared in Comparative Example 5, although the water activity value A of the toner detergent B-5 used therein is in the range of 0.65 to 0.85, the solidity B is less than 0.910, so the fluidity is too low and the cleaning property is poor.

Claims

1. A toner detergent, which is a divalent metal salt of a fatty acid obtained by double decomposition of a fatty acid alkaline compound salt and a divalent metal salt, wherein the fatty acid alkaline compound salt is obtained by reacting a monovalent alkaline compound with a fatty acid having 8 to 24 carbon atoms, wherein the toner detergent is characterized in that: The water activity value A of the divalent metal salt of the fatty acid at 25° C. calculated by the following formula (1) is 0.65 to 0.85, and the number average value B of the solidity defined by the ratio of the projection area to the convex hull area (projection area / convex hull area) in the projection image of the divalent metal salt of the fatty acid with an equivalent circle diameter in the range of cumulative 10% diameter to cumulative 90% diameter on a volume basis is 0.910 to 0.990, Formula (1) A=P / P0 P: Water vapor pressure at 25°C in a sealed container containing a divalent metal salt of a fatty acid (Pa) P0: Vapor pressure of water at 25°C (Pa).

2. The toner cleaning agent according to claim 1, characterized in that: The divalent metal salt of a fatty acid has a volume-based median particle size (D50) of 0.3 to 5.0 μm as measured by a laser diffraction scattering method.

3. The toner cleaning agent according to claim 1 or 2, characterized in that: The divalent metal contained in the divalent metal salt of fatty acid is at least one selected from the group consisting of zinc, calcium and magnesium.

4. A method for producing a toner detergent, which is a method for producing a divalent metal salt of a fatty acid as the toner detergent according to claim 1 or 2, characterized in that: The manufacturing method comprises the following steps: A step of preparing a slurry of a divalent metal salt of a fatty acid by reacting a monovalent alkaline compound with a fatty acid having 8 to 24 carbon atoms and reacting the obtained fatty acid alkaline compound salt with a divalent metal salt in an aqueous solution through a double decomposition method; A step of obtaining a water-containing cake of a divalent metal salt of a fatty acid from the slurry; The step of drying the water-containing cake by hot air at a temperature not less than the melting point of the divalent metal salt of the fatty acid and not more than 200° C., thereby drying and crushing the water-containing cake.

5. A toner composition, characterized in that: The toner detergent comprises the toner detergent according to claim 1 or 2 and toner mother particles, wherein the toner detergent is contained in a ratio of 0.01 to 5 parts by mass based on 100 parts by mass of the toner mother particles.

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