Toner cartridge

Abstract

To provide a toner cartridge that allows a toner filled into the toner cartridge to maintain low temperature fixability and have excellent heat-resistant storage properties to prevent the occurrence of fogging, and can smoothly perform toner supply even when the toner cartridge receives the high-temperature heat history.SOLUTION: A toner with the following configuration is filled into a toner cartridge in which a toner discharge part is located above a toner filling tank in a state where the toner cartridge is mounted in an image forming apparatus. The toner includes aluminum hydroxide coated silica particles as an external additive, and the surface of the aluminum hydroxide coated silica particle is subjected to hydrophobic treatment. A surface area ratio A that is the ratio of the surface area of one toner particle to the total surface area of the aluminum hydroxide coated silica particles attached to one toner particle is 0.6 or more and 5.9 or less. The capacity P (μm) of air present per unit surface area of the aluminum hydroxide coated silica particle is 0.3 or more and 10 or less.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present disclosure relates to a toner cartridge filled with toner. [Background technology]

[0002] In recent years, there has been a demand for further energy saving in image forming devices such as electrophotographic copying machines, multifunction machines, printers, and facsimile machines. Generally, electrostatic latent image developing toner is configured by attaching external additives to the surface of toner particles (toner cores), and when designing the resin (toner resin) that constitutes the toner particles, it is necessary to design it so that it can be fixed at a lower temperature. In the following, toner with such improved low-temperature fixing property is also called low-temperature fixing toner.

[0003] In addition, due to the strong need to miniaturize image forming devices, the configurations of toner cartridges and image forming devices are becoming more complex, such as in many cases being unable to place the toner directly above the developer tank in order to allow freedom in the layout of the toner cartridge (toner refill container) and developer tank.

[0004] Patent Document 1 discloses an external additive for a toner for developing electrostatic latent images, which has a structure in which at least a portion of the surface of silica particles is coated with an oxide, hydroxide or mixture of a metal element, and at least a portion of the oxide, hydroxide or mixture of the metal element is further coated with a fatty acid. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] JP 2019-109297 A Summary of the Invention [Problem to be solved by the invention]

[0006] As a toner cartridge that supplies toner to an image forming device by discharging toner from a toner filling tank filled with toner, there is a configuration in which a discharge section that discharges toner when the toner cartridge is attached to the image forming device is located at the top of the toner filling tank, and the toner is transported upward and discharged from the discharge section by the rotating action of a toner transport member provided in the toner filling tank.

[0007] An example of a toner cartridge having such a configuration is shown in Figures 4 to 6. Figure 4 is a cross-sectional view that shows a schematic diagram of toner cartridge 100 in a state where it is attached to developing tank 200 provided in an image forming apparatus, Figure 5 is a cross-sectional view that shows a state where toner cartridge 100 is filled with toner, and Figure 6 is a top view of toner cartridge 100. In toner cartridge 100 shown in Figures 4 to 6, the toner transport member is composed of agitating film 103, film fixing portion 104, and film rotating shaft 105, and the discharge portion that discharges toner is composed of discharge screw 106 and discharge port 107, and the discharge portion is located above film rotating shaft 105.

[0008] 5, the toner filled in toner filling tank 102 is transported to a discharge section composed of discharge screw 106 and discharge port 107 by the rotation of a toner transport member composed of agitating film 103, film fixing section 104, and film rotating shaft 105. Since discharge port 107 is connected to supply receiving port 204, the toner discharged from discharge port 107 is supplied to developing tank 200.

[0009] A toner cartridge in which toner is filled in a toner filling tank is mounted on an image forming apparatus and used after undergoing environmental changes due to transportation, storage, etc., but in the toner cartridge 100 illustrated in Figures 4 to 6, there is an area indicated by reference numeral 111 in Figures 5 and 6 where the toner transport member (agitation film 103) and discharge screw 106 cannot pass through and are difficult to agitate, and if the toner filled in this area clumps together and forms a wall, there is a problem that the toner cannot be smoothly discharged from the toner cartridge 100 and toner cannot be smoothly replenished to the developing tank 200. This problem is prominent in a toner cartridge after it has been placed in a high-temperature environment, in other words, in a toner cartridge that has been subjected to a high-temperature thermal history.

[0010] It is preferable to fill toner cartridge 100 with more toner and increase the bulk filling rate of toner relative to the volume of toner tank 102, since this reduces the amount of air (water vapor) present in toner tank 102. However, due to restrictions imposed by the shape of toner cartridge 100, if the amount of toner filled is increased, toner also fills and remains in the path leading to discharge screw 106, and the wall formed by the toner clumping due to the high temperature thermal history cannot be broken down, resulting in problems with toner replenishment.

[0011] In addition, it is desirable for the toner filled in the toner cartridge to have heat-resistant storage stability that allows it to maintain its performance even when subjected to high-temperature thermal history, and not to cause fogging even when the temperature and humidity change. However, low-temperature fixing toners designed with resins that can be fixed at lower temperatures have the problem that their heat-resistant storage stability is easily deteriorated when they absorb moisture in a high-humidity environment. Incidentally, fogging refers to the phenomenon in which low-charge toner is developed in non-image areas where toner is not normally developed (the phenomenon in which low-charge toner adheres to the photoconductor).

[0012] The toner cartridge of the present disclosure was discovered in consideration of the above circumstances, and its main objective is to provide a toner cartridge in which the toner filled in the toner cartridge maintains low-temperature fixability while having excellent heat-resistant storage stability, can suppress the occurrence of fogging, and allows smooth toner replenishment even when the toner is subjected to a high-temperature thermal history. [Means for solving the problem]

[0013] The toner cartridge disclosed herein, which has been made to solve the above problems, is a toner cartridge that is detachable from an image forming apparatus, and includes a toner tank filled with toner and a discharge section for discharging the toner from the toner tank. When the toner cartridge is attached to the image forming apparatus, the discharge section is located above the toner tank, and the toner is transported by a rotational operation of a toner transport member provided in the toner tank and discharged from the discharge section, thereby supplying the toner to the image forming apparatus. The toner is a toner having an external additive attached to the surface of the toner particles, and the external additive includes aluminum hydroxide-coated silica particles, which are silica particles whose surfaces are coated with aluminum hydroxide, and the surfaces of the aluminum hydroxide-coated silica particles are hydrophobized. When the total surface area of ​​the aluminum hydroxide-coated silica particles attached to each toner particle is S(Al) and the surface area of ​​each toner particle is S(T), the surface area ratio A expressed by the following formula (1) is 0.6 to 5.9. The amount of air P [μm] present per unit surface area of ​​the aluminum hydroxide-coated silica particles, calculated by dividing the volume of air contained in the toner filling tank filled with the toner by the total surface area of ​​the aluminum hydroxide-coated silica particles contained in the toner filling tank, is 0.3 or more and 10 or less. A = S(A1) / S(T) (1)

[0014] In the above toner cartridge, it is preferable that the average primary particle diameter of the silica particles in the aluminum hydroxide-coated silica particles is 8 nm or more and 45 nm or less.

[0015] In addition, in the above toner cartridge, it is preferable that the average primary particle diameter of the silica particles in the aluminum hydroxide-coated silica particles is 10 nm or more and 30 nm or less, and the thickness of the coating layer of aluminum hydroxide in the aluminum hydroxide-coated silica particles is 0.05 nm or more and 0.5 nm or less.

[0016] In the above toner cartridge, it is preferable that the surface area ratio A is 1.45 or more and 5.9 or less.

[0017] In the above toner cartridge, it is preferable that the hydrophobicity of the aluminum hydroxide-coated silica particles is 45% or more and 85% or less.

[0018] In the toner cartridge, it is preferable that the bulk filling rate of the toner with respect to the volume of the toner tank is 75% or more and 95% or less. Effect of the Invention

[0019] The toner cartridge of the present disclosure provides excellent effects, such as the toner filled in the toner cartridge maintaining low-temperature fixing properties while having excellent heat-resistant storage stability and suppressing the occurrence of fogging, and allowing smooth toner replenishment even when the toner cartridge is subjected to high-temperature thermal history. [Brief description of the drawings]

[0020] [Figure 1] 2 is a schematic diagram showing toner filled in a toner cartridge according to the embodiment; FIG. [Diagram 2] 5A and 5B are schematic diagrams illustrating a mechanism by which the occurrence of aggregation is suppressed in the toner filled in the toner cartridge according to the embodiment. [Diagram 3] FIG. 2 is a schematic diagram showing how aggregation occurs in a conventional toner to which silica particles not coated with aluminum hydroxide are externally added. [Figure 4]1 is a cross-sectional view illustrating a toner cartridge according to an embodiment of the present invention in a state where the toner cartridge is attached to an image forming apparatus. [Diagram 5] 5 is a cross-sectional view showing a state in which the toner cartridge shown in FIG. 4 is filled with toner. [Figure 6] FIG. 6 is a top view of the toner cartridge shown in FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0021] Hereinafter, an embodiment of the toner cartridge of the present disclosure will be described in detail. First, the characteristics of the toner cartridge as a whole will be described, and then the characteristics of the toner filled in the toner cartridge will be described.

[0022] In the present disclosure, "external addition" means adding (adhering) to the surface of a particle, and "internal addition" means adding (containing) inside the particle.

[0023] 1. Toner Cartridge The toner cartridge according to this embodiment is a toner cartridge that is detachably mountable to an image forming apparatus, and includes a toner tank filled with toner, and a discharge section that discharges the toner from the toner tank.

[0024] When the toner cartridge of this embodiment is attached to an image forming device, the discharge section that discharges toner is located at the top of the toner filling tank, and the toner is transported by the rotational action of a toner transport member provided in the toner filling tank and discharged from the discharge section, thereby replenishing toner to the image forming device.

[0025] An example of the toner cartridge according to the present embodiment is a toner cartridge 100 shown in FIGS. 4 to 6, in which a toner transport member is composed of an agitating film 103, a film fixing portion 104, and a film rotating shaft 105, and a discharge portion for discharging toner is composed of a discharge screw 106 and a discharge port 107. In the toner cartridge 100, the discharge portion for discharging toner is located above the film rotating shaft 105. In a toner cartridge that supplies toner to an image forming apparatus by transporting toner from a toner reservoir 110 to an upper portion and dropping the toner from a discharge port 107, as in the toner cartridge 100, the above-mentioned problem of "toner not being discharged smoothly from the toner cartridge" is prominent, but by filling the toner according to the present embodiment, it is possible to smoothly supply toner even in such a toner cartridge.

[0026] Here, the mechanism by which the toner cartridge according to this embodiment can smoothly replenish toner even when subjected to a high-temperature thermal history will be described with reference to FIGS.

[0027] Fig. 3 is a schematic diagram showing how aggregation occurs in a conventional toner to which silica particles (silica particles not coated with aluminum hydroxide) are externally added. In a high humidity environment, many water molecules are present around the toner, and when the toner passes through a high temperature environment in this state (is subjected to high temperature thermal history), the presence of water at the contact points between the resins of the toner particles (points indicated by arrows in Fig. 3) causes the toner particles to bond together and aggregate. As a result, the toner solidifies in areas where the toner is not stirred, as shown by reference numeral 111 in Figs. 5 and 6, causing problems such as the toner not being smoothly discharged from the toner cartridge and the heat resistance of the toner decreasing. This problem is prominent when the toner resin is a polyester resin.

[0028] In contrast, the toner filled in the toner cartridge according to the present embodiment is a toner having aluminum hydroxide-coated silica particles attached to the surface of the toner particles as an external additive, as shown in FIG. 1. Here, the "aluminum hydroxide-coated silica particles" refer to silica particles whose surfaces are coated with aluminum hydroxide. In the toner filled in the toner cartridge according to the present embodiment, even when exposed to high humidity during toner filling or toner cartridge transportation, as shown in FIG. 2, the aluminum hydroxide-coated silica particles take over part of the moisture absorption of the toner resin, thereby reducing the moisture absorption of the toner and preventing the toner particles from bonding together and causing aggregation. As a result, it is possible to provide a toner cartridge that can prevent the deterioration of the heat resistance of the toner in a high humidity environment and allows smooth toner replenishment even when the toner cartridge is subjected to a high-temperature thermal history.

[0029] In addition, in the toner cartridge according to the present embodiment, the walls formed by the aggregation of toner crumble stably, so that the toner tank can be filled with more toner, and the proportion of air in the toner tank can be reduced, and the effect of water vapor in the outside air on the toner can be reduced. This makes it possible to further suppress the deterioration of the heat resistance of the toner, and toner cartridges that allow smoother toner replenishment can be achieved.

[0030] In the toner cartridge according to the present embodiment, the toner bulk filling rate relative to the volume of the toner tank is preferably 75% to 95%, and more preferably 85% to 95%. By keeping the toner bulk filling rate within the above range, the proportion of air in the toner tank can be reduced as described above, and the effect of water vapor in the outside air on the toner can be reduced.

[0031] Next, the characteristics of the toner filled in the toner cartridge according to this embodiment will be described.

[0032] 2. Toner particles (toner cores) The toner particles according to the present embodiment are composed of an internal additive such as a colorant and a binder resin, and the internal additive is dispersed in the binder resin. An external additive is attached to the surface of the toner particles. If necessary, the toner particles may further contain optional components within a range that does not impair the effects of the present disclosure.

[0033] The volume average particle diameter of the toner particles can be appropriately selected depending on the purpose, but is preferably 4 μm to 8 μm. By reducing the volume average particle diameter to fall within the above range, high-definition images can be stably formed over a long period of time, high image density can be obtained even with a small amount of toner adhesion, and toner consumption can be reduced.

[0034] The method for producing the toner particles is not particularly limited, and for example, the toner particles can be produced by a pulverization method. The toner particles can be produced by a pulverization method, for example, by carrying out a mixing step of dry-mixing raw materials including an internal additive such as a colorant and a binder resin in a mixer, a melting and kneading step of melting and kneading the obtained mixture in a kneader, a pulverization step of cooling and solidifying the obtained molten kneaded product, pulverizing the solidified product in a pulverizer to obtain a finely pulverized product, and a classification step of adjusting the particle size of the obtained finely pulverized product using a classifier or the like as necessary.

[0035] 2-1. Binder resin The binder resin in the toner particles according to the present embodiment may be a resin commonly used in the field of electrophotography, such as polyester resins, polystyrene resins such as styrene-acrylic resins, (meth)acrylic acid ester resins, polyolefin resins, polyurethane resins, and epoxy resins. One of these may be used alone, or two or more may be used in combination.

[0036] Among them, amorphous polyester resins are preferred, and it is more preferred to use a combination of an amorphous polyester resin made of a low molecular weight component and an amorphous polyester resin made of a medium to high molecular weight component. This can improve the productivity, quality, and performance of the toner according to the present embodiment. In this disclosure, the terms low molecular weight, medium molecular weight, and high molecular weight are used in a relative comparison of the molecular weight distribution of polyester resins, and will be described later.

[0037] In the present disclosure, crystalline resins and amorphous resins are distinguished by their crystallinity index, with a resin having a crystallinity index in the range of 0.6 to 1.5 being crystalline resins, and a resin having a crystallinity index less than 0.6 or more than 1.5 being amorphous resins. Resins having a crystallinity index greater than 1.5 are amorphous, and resins having a crystallinity index less than 0.6 have low crystallinity and many amorphous portions.

[0038] The crystallinity index is a physical property that is an index of the degree of crystallization of a resin, and is defined as the ratio of the softening point to the highest endothermic peak temperature (softening point / highest endothermic peak temperature). Here, the highest endothermic peak temperature refers to the temperature of the highest endothermic peak observed. In a crystalline polyester resin, the highest peak temperature is the melting temperature (melting point), and in an amorphous polyester resin, the highest endothermic peak is the glass transition point.

[0039] The degree of crystallization can be controlled by adjusting the types and ratio of raw material monomers, as well as production conditions (for example, reaction temperature, reaction time, cooling rate), and the like.

[0040] <Amorphous polyester resin> The amorphous polyester resin is a polyester resin having a crystallinity index of less than 0.6 or more than 1.5, with a polyester resin having a crystallinity index of more than 1.5 being preferred.

[0041] The amorphous polyester resin is not particularly limited, but may be obtained, for example, by a polycondensation reaction between a carboxylic acid monomer containing terephthalic acid or isophthalic acid as a main component and a polyhydric alcohol containing ethylene glycol as a main component.

[0042] The reaction conditions are the same as those for producing ordinary polyester resins, and for example, a dicarboxylic acid monomer and a polyhydric alcohol are reacted in a nitrogen gas atmosphere, optionally in the presence of an esterification catalyst, at a temperature of 190 to 240° C. to obtain an amorphous polyester resin. The reaction ratio of the polyhydric alcohol and the carboxylic acid monomer is preferably 1.3:1 to 1:1.2 in terms of the equivalent ratio of hydroxyl group to carboxyl group [OH]:[COOH].

[0043] The molar content of terephthalic acid or isophthalic acid in the dicarboxylic acid monomer is preferably 70% to 100%, and more preferably 80% to 100%.

[0044] The dicarboxylic acid monomer may also include aromatic dicarboxylic acids such as fumaric acid, and aliphatic dicarboxylic acids such as adipic acid, sebacic acid, and succinic acid, and may also include ester-forming derivatives of terephthalic acid or isophthalic acid, ester-forming derivatives of aromatic dicarboxylic acids, ester-forming derivatives of aliphatic dicarboxylic acids, and acid anhydrides and alkyl esters of these carboxylic acids.

[0045] Furthermore, the dicarboxylic acid monomer may be used in combination with a trivalent or higher polycarboxylic acid such as trimellitic acid or pyromellitic acid, or an ester-forming derivative thereof.

[0046] The above dicarboxylic acid monomers and polycarboxylic acid monomers may be used alone or in combination of two or more.

[0047] The molar content of ethylene glycol in the polyhydric alcohol is preferably 70 to 100%, more preferably 80 to 100%. The polyhydric alcohol may contain other polyhydric alcohols such as 1,3-propylene glycol and 1,4-butanediol.

[0048] The above polyhydric alcohols may be used alone or in combination of two or more.

[0049] <Crystalline polyester resin> The crystalline polyester resin is a polyester resin having a crystallinity index of 0.6 to 1.5, and preferably has a crystallinity index of 0.8 to 1.2.

[0050] The crystalline polyester resin is not particularly limited, but is preferably composed of a linear saturated aliphatic polyester unit obtained by a polycondensation reaction between a carboxylic acid monomer containing, as a main component, an aliphatic dicarboxylic acid having 9 to 22 carbon atoms and a polyhydric alcohol containing, as a main component, an aliphatic diol having 2 to 10 carbon atoms.

[0051] The reaction conditions are the same as those for producing a normal polyester resin, and for example, a crystalline polyester resin is obtained by reacting a dicarboxylic acid monomer with a polyhydric alcohol in a nitrogen gas atmosphere, optionally in the presence of an esterification catalyst, at a temperature of 190 to 240° C. From the viewpoint of the storage stability of the toner, the reaction ratio of the polyhydric alcohol to the carboxylic acid monomer is preferably 0.83:1 to 1.3:1 in terms of the equivalent ratio of hydroxyl group to carboxyl group [OH]:[COOH].

[0052] The molar content of dicarboxylic acid in the carboxylic acid monomer is preferably 90% to 100%. If the molar content of dicarboxylic acid is low, the rate and speed of crystallization may decrease, resulting in insufficient toner aggregation resistance.

[0053] Examples of the aliphatic dicarboxylic acid having 9 to 22 carbon atoms include azelaic acid, zebacinic acid, 1,10-decanedicarboxylic acid, 1,18-octadecanedicarboxylic acid, etc. Furthermore, the carboxylic acid monomer and the polycarboxylic acid monomer may contain an ester-forming derivative of these aliphatic dicarboxylic acids.

[0054] Furthermore, the carboxylic acid monomer may be used in combination with a polycarboxylic acid having three or more valences, such as trimellitic acid or pyromellitic acid, or an ester-forming derivative thereof.

[0055] The above carboxylic acid monomers can be used alone or in combination of two or more.

[0056] The molar content of the aliphatic diol having 2 to 10 carbon atoms in the polyhydric alcohol is preferably 80 to 100%. Examples of the aliphatic diol having 2 to 10 carbon atoms include ethylene glycol, 1,4-butanediol, and 1,6-hexanediol.

[0057] Furthermore, examples of polyhydric alcohols that can be used in combination with the above aliphatic diols include trihydric or higher alcohols such as glycerin and trimethylolpropane.

[0058] The above polyhydric alcohols may be used alone or in combination of two or more.

[0059] <Polyester resins made of low to high molecular weight components> In the following description, the polyester resin made of low molecular weight components will be referred to as resin A, the polyester resin made of medium molecular weight components as resin B, and the polyester resin made of high molecular weight components as resin C.

[0060] (Resin A) Resin A has a molecular weight distribution of 1×10 3 ~1×10 4 At 80°C during flow tester measurement, the 5 It has a viscosity of less than Pa·s.

[0061] mass molecular weight 1×10 3 If the molecular weight distribution is less than 1×10, the resin becomes soft and the storage stability of the toner may deteriorate. 4 If the molecular weight distribution exceeds 1×10, the viscosity of the resin increases and the low-temperature fixing property of the toner may deteriorate. 3 ~1×10 4 The molecular weight distribution in this range is preferably 80% or more.

[0062] Resin A is 1×10 at 80℃ when measured with a flow tester. 5 When the viscosity is less than 1×10 Pa·s, good low-temperature fixing properties suitable for low-temperature fixing such as pad fixing can be obtained. 5 If the viscosity exceeds Pa·s, the low-temperature fixing property of the toner may deteriorate. The viscosity at 80°C measured with a flow tester is 2×10 4 Resin A preferably has a glass transition temperature Tg [°C] of 52°C to 56°C, and a softening point Tm [°C] of 85°C to 100°C.

[0063] (Resin B) Resin B has a molecular weight distribution of 1×10 4 ~1×10 5 Distributed in the range of 20% or more and has a molecular weight of 1×10 3 ~1×10 4 Resin B contributes to uniform melt-kneading of Resin A and Resin C. If Resin B is not blended, not only the low-temperature fixability but also the high-temperature fixability of the toner may not be ensured.

[0064] Since Resin B is adjusted to have a viscosity between that of the low molecular weight component and the high molecular weight component, it has good mixability and kneadability with other resins, so it is possible to disperse various raw materials in Resin B in advance.

[0065] Resin B has a molecular weight distribution of 1×10 4 ~1×10 5and the molecular weight is 1×10 3 ~1×10 4 If the resin does not have a main peak in this range, it becomes difficult to uniformly melt-knead resin A and resin C, and it may become difficult to ensure not only low-temperature fixability but also high-temperature fixability.

[0066] Resin B preferably has a glass transition temperature Tg [°C] of 65°C to 70°C, and a softening point Tm [°C] of 110°C to 120°C.

[0067] (Resin C) Resin C has a molecular weight distribution of 1×10 5 The resin content is distributed within the above range by 5% or more. While resin A contributes to low viscosity, resin C contributes to ensuring high-temperature fixability.

[0068] Resin C has a molecular weight distribution of 1×10 5 If the distribution is not 5% or more within the above range, the elasticity of the toner is lost and high-temperature fixability may not be ensured. 5 If the deviation is less than 5% from the above range, the low temperature region for pad fixing may not be ensured.

[0069] Resin C may contain a gel component. In order to improve the fixing quality on the high temperature side of the fixing region, it is preferable that the resin C has a gel content of 3% to 20% by mass. If the gel content of resin C exceeds 20% by mass, the grindability may be deteriorated.

[0070] Resin C preferably has a glass transition temperature Tg [°C] of 55°C to 65°C, and a softening point Tm [°C] of 130°C to 150°C.

[0071] (Mixing ratio of resins A to C) The blending ratios of resin A, resin B, and resin C can be appropriately set based on the physical properties of the resin raw materials used, within a range that does not impair the effects of the present disclosure. For example, when the total amount of the binder resin is taken as 100% by mass, resin A can be in the range of 25% by mass to 60% by mass, resin B can be in the range of 5% by mass to 20% by mass, and resin C can be in the range of 30% by mass to 60% by mass.

[0072] It is preferable that the composition ratio of resin A and resin C satisfy the relationship of resin A≦resin C. When the binder resin contains more resin A than resin C, the low-temperature fixing property of resin A is strongly expressed, and the high-temperature side region of the fixing region may not be sufficiently secured.

[0073] Resin B preferably has a composition ratio of 5% by mass to 20% by mass with respect to the total amount of binder resin. If resin B is less than 5% by mass with respect to the total amount of binder resin, sufficient melting and kneading may not be possible, and the high temperature side area of ​​the fixing area may not be sufficiently secured. If resin B exceeds 20% by mass with respect to the total amount of binder resin, when the composition ratio of resin A is large, the high temperature side area of ​​the fixing area may not be sufficiently secured, and when the composition ratio of resin C is large, the low temperature side area of ​​the fixing area may not be sufficiently secured. The composition ratio of resin B is more preferably 8% by mass to 15% by mass with respect to the total amount of binder resin.

[0074] 2-2.Coloring agents The colorant contained in the toner particles according to the present embodiment may be any organic or inorganic pigment or dye commonly used in the field of electrophotography, and the type and color are not particularly limited. For example, black, white, yellow, orange, red, purple, blue, and green colorants may be used.

[0075] Examples of black colorants include carbon black, copper oxide, manganese dioxide, aniline black, activated carbon, non-magnetic ferrite, magnetic ferrite, and magnetite.

[0076] Examples of white colorants include zinc oxide, titanium oxide, antimony white, and zinc sulfide.

[0077] Examples of yellow colorants include yellow lead, zinc yellow, cadmium yellow, yellow iron oxide, mineral fast yellow, nickel titanium yellow, navel yellow, naphthol yellow S, Hansa Yellow G, Hansa Yellow 10G, benzidine yellow G, benzidine yellow GR, quinoline yellow lake, permanent yellow NCG, tartrazine lake, CI Pigment Yellow 12, CI Pigment Yellow 13, CI Pigment Yellow 14, CI Pigment Yellow 15, CI Pigment Yellow 17, CI Pigment Yellow 93, CI Pigment Yellow 94, and CI Pigment Yellow 138.

[0078] Examples of orange colorants include red yellow lead, molybdenum orange, permanent orange GTR, pyrazolone orange, Balkan orange, industhrene brilliant orange RK, benzidine orange G, industhrene brilliant orange GK, CI pigment orange 31, and CI pigment orange 43.

[0079] Examples of red colorants include red iron oxide, cadmium red, red lead, mercury sulfide, cadmium, permanent red 4R, lithol red, pyrazolone red, watching red, calcium salt, lake red C, lake red D, brilliant carmine 6B, eosin lake, rhodamine lake B, alizarin lake, brilliant carmine 3B, CI pigment red 2, CI pigment red 3, CI pigment red 5, CI pigment red 6, CI pigment red 7, CI pigment red 8, CI pigment red 9, CI pigment red 10, CI pigment red 11, CI pigment red 12, CI pigment red 13, CI pigment red 14, CI pigment red 15, CI pigment red 16, CI pigment red 17, CI pigment red 18, CI pigment red 19, CI pigment red 20, CI pigment red 21, CI pigment red 22, CI pigment red 23, CI pigment red 24, CI pigment red 25, CI pigment red 26, CI pigment red 27, CI pigment red 28, CI pigment red 29, CI pigment red 30, CI pigment red 31, CI pigment red 32, CI pigment red 33, CI pigment red 34, CI pigment red 35, CI pigment red 36, CI pigment red 37, CI pigment red 38, CI pigment red 39 ... Examples of pigment red include CI Pigment Red 7, CI Pigment Red 15, CI Pigment Red 16, CI Pigment Red 48:1, CI Pigment Red 53:1, CI Pigment Red 57:1, CI Pigment Red 122, CI Pigment Red 123, CI Pigment Red 139, CI Pigment Red 144, CI Pigment Red 149, CI Pigment Red 166, CI Pigment Red 177, CI Pigment Red 178, and CI Pigment Red 222.

[0080] Examples of purple colorants include manganese purple, fast violet B, and methyl violet lake.

[0081] Examples of blue colorants include Prussian blue, cobalt blue, alkali blue lake, Victoria blue lake, phthalocyanine blue, metal-free phthalocyanine blue, partially chlorinated phthalocyanine blue, fast sky blue, indanthrene blue BC, CI pigment blue 15, CI pigment blue 15:2, CI pigment blue 15:3, CI pigment blue 16, and CI pigment blue 60.

[0082] Examples of green colorants include chrome green, chromium oxide, pigment green B, mica light green lake, final yellow green G, CI pigment green 7, and the like.

[0083] In this embodiment, one of the above colorants can be used alone or two or more can be used in combination, and the combination may be of different colors or the same color. Two or more colorants may be used in the form of composite particles. The composite particles can be produced, for example, by adding an appropriate amount of water, lower alcohol, etc. to two or more colorants, granulating them with a general granulator such as a high-speed mill, and drying them.

[0084] Furthermore, in order to disperse the colorant uniformly in the binder resin, the colorant may be used in the form of a master batch. The composite particles and the master batch are mixed into the toner composition during dry mixing.

[0085] The content of the colorant is not particularly limited, but is preferably 3 parts by mass or more and 15 parts by mass or less, and more preferably 5 parts by mass or more and 12 parts by mass or less, relative to 100 parts by mass of the binder resin. If the content of the colorant is within the above range, it is possible to form an image having a high image density and very good image quality without impairing various physical properties of the toner.

[0086] 2-3. Release agent The toner particles according to the present embodiment contain a wax as a release agent. The wax may be any wax commonly used in the field of electrophotography. For example, petroleum waxes such as paraffin wax and microcrystalline wax and their derivatives; hydrocarbon synthetic waxes such as Fischer-Tropsch wax, polyolefin wax (polyethylene wax, polypropylene wax, etc.), low molecular weight polypropylene wax and polyolefin polymer wax (low molecular weight polyethylene wax, etc.) and their derivatives; vegetable waxes such as carnauba wax, rice wax, candelilla wax and their derivatives, and Japan wax; animal waxes such as beeswax and spermaceti; oil-based synthetic waxes such as fatty acid amides and phenol fatty acid esters; long-chain carboxylic acids and their derivatives; long-chain alcohols and their derivatives; silicone polymers; higher fatty acids, etc.

[0087] The above derivatives include oxides, block copolymers of vinyl monomers and wax, and graft modified products of vinyl monomers and wax.

[0088] In the present embodiment, one of the waxes described above may be used alone, or two or more of them may be used in combination.

[0089] The toner particles according to the present embodiment preferably contain two types of release agents having a melting point difference of 30° C. or more, that is, a release agent A on the low melting point side and a release agent B on the high melting point side.

[0090] Release agent A preferably has a melting point of 100° C. or less. If the melting point of release agent A exceeds 100° C., the releasability of the recording medium (paper, etc.) from the belt or roller may deteriorate in the low-temperature region of the fixing area. Release agent B preferably has a melting point of 120° C. or more. If the melting point of release agent B is less than 120° C., the releasability of the recording medium from the belt or roller may deteriorate in the high-temperature region of the fixing area.

[0091] If the difference in melting points between the two release agents is less than 30° C. and leans toward the low melting point side, the grindability during toner production may deteriorate. If the difference in melting points between the two release agents is less than 30° C. and leans toward the high melting point side, peeling failure may occur in the low temperature region of the fixing region.

[0092] The release agent A is preferably an ester wax, a paraffin wax or a polyethylene wax, and the release agent B is preferably a polypropylene wax.

[0093] The content of the release agent in the toner particles is not particularly limited, but is preferably 1 part by mass or more and 5 parts by mass or less, more preferably 1.5 parts by mass or more and 4 parts by mass or less, and particularly preferably 2 parts by mass or more and 3 parts by mass or less, relative to 100 parts by mass of the binder resin. When two types of release agents, release agent A and release agent B, are used, the total amount of the two types of release agents is preferably within the above range, and the ratio A / B of the content of release agent A to release agent B is preferably 0.8 to 3.

[0094] 2-4.Other internal additives Furthermore, the toner particles according to this embodiment may contain, as internal additives, charge control agents, wax dispersants, grinding aids, and the like that are used in the field of electrophotography.

[0095] As the charge control agent, charge control agents for positive charge control and negative charge control used in the field of electrophotography can be used. As the charge control agent for positive charge control, for example, quaternary ammonium salts, pyrimidine compounds, triphenylmethane derivatives, guanidine salts, amidine salts, etc. can be used. As the charge control agent for negative charge control, metal-containing azo compounds, azo complex dyes, metal complexes and metal salts of salicylic acid and its derivatives (metals are chromium, zinc, zirconium, etc.), organic bentonite compounds, boron compounds, etc. can be used.

[0096] The content of the charge control agent in the toner particles is not particularly limited, but is preferably 0.5 parts by mass or more and 3 parts by mass or less, and more preferably 1 part by mass or more and 2 parts by mass or less, per 100 parts by mass of the binder resin.

[0097] 3.External additives The toner according to the present embodiment contains aluminum hydroxide-coated silica particles as an external additive, and the surfaces of the aluminum hydroxide-coated silica particles are hydrophobized. Here, the aluminum hydroxide-coated silica particles are silica particles whose surfaces are coated with aluminum hydroxide. Note that "surface-coated with aluminum hydroxide" does not only mean that the entire surface of the silica particles is coated with aluminum hydroxide, but may mean that at least a part of the surface of the silica particles is coated with aluminum hydroxide.

[0098] The method for producing the aluminum hydroxide-coated silica particles is not particularly limited, but they can be produced according to the "Method for producing aluminum hydroxide-coated silica particles to be used as an external additive" in the Examples section shown later.

[0099] Aluminum hydroxide-coated silica particles are a composition containing aluminum hydroxide and silica particles, with the main component being silica. The aluminum hydroxide content is, for example, 5% by mass or more and 15% by mass or less, and preferably 8% by mass or more and 12% by mass or less.

[0100] The surface of the aluminum hydroxide-coated silica particles is hydrophobized, and the hydrophobization is preferably silane treatment. Silane treatment means surface modification using a silane coupling agent, and examples of the silane coupling agent include hexamethyldisilazane (HMDS), dimethyldichlorosilane (DDS), octylsilane (OTAS), polydimethylsiloxane (PDMS), and the like. By hydrophobizing the surface of the aluminum hydroxide-coated silica particles, it is possible to suppress the occurrence of fogging in a high-temperature, high-humidity environment, which is easily aggravated by the presence of the aluminum hydroxide coating layer. In addition, it is possible to further suppress the occurrence of fogging in a high-temperature, high-humidity environment by appropriately designing the thickness of the aluminum hydroxide coating layer.

[0101] In the toner according to this embodiment, when the total surface area of ​​the aluminum hydroxide-coated silica particles adhered to each toner particle is S(Al) and the surface area per each toner particle is S(T), the surface area ratio A represented by the following formula (1) is 0.6 or more and 5.9 or less, preferably 1.45 or more and 5.9 or less, and more preferably 1.45 or more and 4.5 or less. A = S(A1) / S(T) (1)

[0102] By having the surface area ratio A within the above range, the toner filled in the toner cartridge can maintain its low-temperature fixing ability while improving its heat-resistant storage stability, and a toner cartridge can be realized that allows smooth toner replenishment even when it is subjected to a high-temperature thermal history.

[0103] The content of the aluminum hydroxide-coated silica particles in the toner according to this embodiment is preferably from 0.4 to 3 parts by mass, more preferably from 0.6 to 2 parts by mass, and particularly preferably from 0.6 to 1.4 parts by mass, per 100 parts by mass of the toner particles.

[0104] In the toner cartridge according to the present embodiment, the amount of air P [μm] present per unit surface area of ​​the aluminum hydroxide-coated silica particles, calculated by dividing the volume of air contained in a toner tank filled with toner by the total surface area of ​​the aluminum hydroxide-coated silica particles contained in the toner tank, is 0.3 to 10, preferably 0.32 to 6.1. By having the air amount P within the above range, the above-mentioned effect of "the aluminum hydroxide-coated silica particles partially take over the moisture absorption of the toner resin, thereby reducing the moisture absorption of the toner and preventing the toner particles from bonding together and causing aggregation" is fully exhibited, which in turn makes it possible to prevent the deterioration of the heat resistance of the toner in a high humidity environment and realize a toner cartridge that allows smooth toner replenishment even when subjected to a high-temperature thermal history.

[0105] The average primary particle size of the silica particles (silica base material) in the aluminum hydroxide-coated silica particles is preferably 8 nm to 45 nm, more preferably 10 nm to 30 nm, and particularly preferably 10 nm to 25 nm. By using silica particles (silica base material) with a small particle size, the fluidity is improved and the surface area of ​​the aluminum hydroxide coating layer is also increased, so that the above-mentioned effect of "the aluminum hydroxide-coated silica particles partially take over the moisture absorption of the toner resin, thereby reducing the moisture absorption of the toner and suppressing the bonding of toner particles to each other and the occurrence of aggregation" can be further enhanced.

[0106] In the aluminum hydroxide-coated silica particles, the thickness of the coating layer of aluminum hydroxide is preferably 0.05 nm or more and 0.5 nm or less, more preferably 0.1 nm or more and 0.45 nm or less, and even more preferably 0.15 nm or more and 0.4 nm or less. When silica particles (silica substrate) with a small particle size are used, the surface area of ​​the aluminum hydroxide coating layer also increases, but if the coating layer becomes too thin, the effect of electrical conductivity is locally attenuated. Therefore, by having the thickness of the coating layer be equal to or greater than the above lower limit, the charge in a low-humidity environment can be effectively released, and especially during continuous printing in a low-humidity environment, the toner highly charged in the developer is difficult to develop and remains in the developer for a long time, which can suppress the occurrence of fogging (high-charge fogging) that occurs when the newly replenished toner cannot be charged quickly. If the thickness of the coating layer exceeds the above upper limit, the charge becomes too easy to escape, and fogging in a high-temperature and high-humidity environment may worsen. In addition, it is preferable that the aluminum hydroxide-coated silica particles satisfy the above-mentioned preferred range of the thickness of the coating layer and also satisfy the above-mentioned preferred range of the average primary particle diameter of the silica particles (silica substrate).This makes the ratio of the silica particles (silica substrate) and the coating layer in the aluminum hydroxide-coated silica particles appropriate, and can sufficiently obtain the effect of suppressing the occurrence of fogging.

[0107] The hydrophobicity of the aluminum hydroxide-coated silica particles is preferably 45% or more and 85% or less, and more preferably 60% or more and 85% or less. When the hydrophobicity of the aluminum hydroxide-coated silica particles is within the above range, the charging performance of the toner is improved, and the occurrence of fogging after being placed in a high-temperature and high-humidity environment can be suppressed. EXAMPLES

[0108] The toner cartridge of the present disclosure will be specifically described below based on examples and comparative examples. First, various measurement and calculation methods and evaluation methods will be described.

[0109] <Method for measuring the softening point of polyester resin> Using a flow characteristic evaluation device (Shimadzu Corporation, Flow Tester, Model: CFT-100C), 1 g of sample was heated at a temperature increase rate of 6°C / min while applying a load of 20 kgf / cm 2 (9.8×10 5 The sample was allowed to flow out from a die (nozzle diameter 1 mm, length 1 mm) at a pressure of 1 Pa. The temperature at which half of the sample had flowed out was taken as the softening point Tm [°C].

[0110] <Method for measuring viscosity of polyester resin> The measurement was carried out using the same equipment and conditions as for the softening point above, and the viscosity [Pa s] was automatically calculated from the plunger sedimentation curve.

[0111] <Method for measuring glass transition temperature of polyester resin> A differential scanning calorimeter (manufactured by Hitachi High-Tech Science Corporation, model number: DSC220) was used to measure a DSC curve by heating 1 g of the sample at a heating rate of 10° C. / min in accordance with Japanese Industrial Standards (JIS) K7121-1987. In the obtained DSC curve, the temperature at the intersection of a straight line extending the baseline on the high-temperature side of the endothermic peak corresponding to the glass transition to the low-temperature side and a tangent drawn at the point where the slope of the curve from the rising part of the peak to the apex is maximum was determined as the glass transition temperature Tg [° C.].

[0112] <Method for measuring molecular weight distribution of polyester resin> The polyester resin was dissolved in tetrahydrofuran (THF) to a concentration of 0.25% by mass, and 200 μL of the sample was injected into a GPC apparatus (Tosoh Corporation, model: HLC-8220GPC), and a molecular weight distribution curve was obtained at a temperature of 40° C. The molecular weight distribution was obtained from the obtained molecular weight distribution curve. The molecular weight calibration curve was prepared using standard polystyrene.

[0113] <Method for measuring gel content of polyester resin> Approximately 3.0 g of polyester resin, which had been weighed in advance, was dissolved in 1,000 mL of tetrahydrofuran (THF) at 45°C for 15 minutes, and the insoluble matter was filtered off using an Omnipore membrane filter (Merck, product name: JAWP04700). The insoluble matter remaining on the membrane filter was dried at 85°C for 10 hours, and the mass of the resulting dried product was measured. The mass proportion of this insoluble matter was calculated as the gel content [%].

[0114] <Measuring method for melting point of release agent (wax)> Using a differential scanning calorimeter (manufactured by PerkinElmer Japan, model: Diamond DSC), 0.01 g of wax was heated from 20°C to 200°C at a heating rate of 10°C / min, and then rapidly cooled from 200°C to 20°C twice to measure the DSC curve, and the temperature of the endothermic peak corresponding to melting in the DSC curve measured in the second run was recorded as the melting point of the wax [°C].

[0115] <Method of measuring the volume average particle size of toner particles> 20 mg of toner particles and 1 mL of sodium alkyl ether sulfate were added to 50 mL of electrolyte (manufactured by Beckman Coulter, Inc., product name: ISOTON-II), and the mixture was dispersed for 3 minutes at a frequency of 20 kHz using an ultrasonic disperser (manufactured by AS ONE Corporation, model: tabletop dual-frequency ultrasonic cleaner VS-D100) to prepare a sample for measurement.

[0116] The obtained samples were measured using a particle size distribution analyzer (Beckman Coulter, Inc., model: Multisizer3) under the conditions of aperture diameter: 100 μm, number of particles measured: 50,000 counts, and the volume average particle diameter [μm] was calculated from the volume particle size distribution of the particles in the sample.

[0117] <Method for measuring the average primary particle size of external additives> The average primary particle diameter of the external additive was determined by photographing the toner particles using a scanning electron microscope (SEM) (manufactured by Hitachi High-Technologies Corporation, model: S-4800), measuring the particle diameters (longer diameter) of 100 external additive particles on the toner surface from the obtained image, and calculating the average value of the particle diameters of the 100 particles, which was defined as the average primary particle diameter.

[0118] <How to calculate surface area ratio A> Based on the assumption that the toner particles (core toner) and external additives (aluminum hydroxide-coated silica particles) are spherical and have the same particle size, and that the external additives are uniformly dispersed and attached to the surface of the toner particles on a mass basis, the number n of external additives attached to each toner particle was calculated. Based on this number, the coverage θ CV The surface area ratio A (projected area of ​​the external additive relative to the toner particle surface) was calculated. The surface area ratio A is expressed as A=S(Al) / S(T), where S(Al) is the total surface area of ​​the external additive (aluminum hydroxide-coated silica particles) attached to each toner particle, and S(T) is the surface area per toner particle.

[0119] The formula for calculating the number of external additives, n, is as follows: (Number of parts added / 100)=M A / M T = [n × ρ A ×(4 / 3πr 3 )] / [ρ T ×(4 / 3πR 3 )] (Added parts / 100)=n×(ρ A / ρ T )×(r / R) 3 n=(number of parts added / 100)×(ρT / ρ A )×(R / r) 3

[0120] Coverage θ CV The calculation formula is as follows: θ CV =n×(πr 2 ) / (4πR 2 )=(1 / 4)×n×(r / R) 2 =(1 / 4)×(Added parts / 100)×(ρ T / ρ A )×(R / r)

[0121] The formula for calculating the surface area ratio A is as follows: A = n × (4πr 2 ) / (4πR 2 )=4θ CV

[0122] In these formulas, R is the radius of the toner particle (2R is the particle diameter), ρ T is the density of the toner particles, M T is the mass of one toner particle, r is the radius of the external additive (2r is the particle diameter), ρ A is the density of the external additive, M A indicates the total mass of the external additives attached to each toner particle. Also, "number of parts added" indicates the number of parts of the external additives added per 100 parts by mass of the toner particles.

[0123] <Method for measuring the volume of the toner tank of a toner cartridge> A toner cartridge used in a multifunction machine (product name: MX-B455W, manufactured by Sharp Corporation) was partially modified so that the discharge performance test described below could be performed, and was used as the test toner cartridge in the examples and comparative examples. The volume of the toner tank of the toner cartridge was measured as follows.

[0124] Five representative toner tanks (toner storage containers) were prepared, a hole was drilled in the top and the leak was sealed, water was poured into the tank to fill it just enough to prevent overflow, and the mass of the poured water was calculated from the change in mass before and after pouring the water, and this mass was converted into volume [cc]. The average value for the five containers was calculated and used as the volume of the toner tank.

[0125] <Method of measuring toner bulk density AD> 10 g of toner was placed in a 20 mL plastic container and left for 48 hours at a temperature of 50°C. After leaving it, the bulk density AD (g / cm) of the toner was measured using a bulk density measuring device conforming to Japanese Industrial Standard (JIS) K7365. 3 ) was measured.

[0126] <How to calculate the amount of air P present per unit surface area of ​​external additive> The volume of air contained in a toner tank filled with toner [cm 3 ] is calculated by dividing the total surface area [cm 2 ] to calculate the amount of air present per unit surface area of ​​the aluminum hydroxide-coated silica particles P [cm], and then converting the units to calculate P [μm].

[0127] The volume of air contained in a toner tank filled with toner was calculated by subtracting the filled toner volume (volume occupied by the filled toner) from the volume of the toner tank. Specifically, the following calculation was performed. Note that the "bulk density of the toner" was calculated by fixing it at the density of the toner particles, since it is difficult to calculate it while taking into account external additives.

[0128] Calculating the volume of air (Volume of air) = (Volume of toner tank) - (Volume occupied by toner) (Filled toner mass) = (Filling rate) x (Volume of toner filling tank) / (Bulk density of toner AD) (Volume of filled toner) = (Mass of filled toner) / (Bulk density of toner (1.2 g / cc)) Calculation of the total surface area of ​​external additives (aluminum hydroxide-coated silica particles) (Total surface area of ​​toner) = (Mass of filled toner) x (Specific surface area of ​​toner) (Total surface area of ​​external additives)=(Total surface area of ​​toner)×(Surface area ratio A) Toner specific surface area [m 2 / g]:S = 6 / (D × ρ) (where D is the diameter of the toner particle and ρ is the bulk density of the toner)

[0129] <Method of calculating the thickness of the coating layer of aluminum hydroxide-coated silica particles> Assuming that the silica particles used as the substrate have a spherical shape and that their surfaces are uniformly coated with aluminum hydroxide, the thickness d of the coating layer of the aluminum hydroxide-coated silica particles was calculated as follows.

[0130] The density of the silica particles (base material) is ρ Si , the radius of the silica particle is r Si , the volume of the silica particles is V Si , the density of aluminum hydroxide is ρ Al , the radius of the aluminum hydroxide-coated silica particle (the entire particle including the substrate and the coating layer) is r Al , the volume of the aluminum hydroxide-coated silica particles is V Al Then, Mass of silica particles (base material): M Si =ρ Si (4 / 3)πr Si 3 =ρ Si ×V Si Mass of aluminum hydroxide: M Al =ρ Al {V Al -V Si} Divide both sides of the above two equations to get (M Al / M Si )=(ρ Al / ρ Si ){(r Al / r Si ) 3 -1} (A) If the mass ratio of aluminum hydroxide is m, m=MAl / (M Al +M Si ) Rewriting the above equation (A) using m gives m(1-m)×(ρ Si / ρ Al )=(r Al / r Si ) 3 -1 (r Al / r Si ) 3 =1+m(1-m)×(ρ Si / ρ Al ) (B) The particle size ratio can be calculated from the mass ratio and density, and the particle size can be obtained by multiplying it by the particle size of the silica particles (base material). Therefore, the thickness d of the coating layer can be calculated from the difference in particle sizes, (r Al / r Si ) = the cube root of (B) above d=r Al -r Si =r Si (The cube root of (B) above - 1) = (particle size of silica particles / 2) (cubic root of (B) above - 1)

[0131] <Method for measuring hydrophobicity of aluminum hydroxide-coated silica particles> The hydrophobicity of the aluminum hydroxide-coated silica particles was measured using a methanol drop transmittance curve. 70 mL of a water-containing methanol solution, which was a mixture of 60% by volume of methanol and 40% by volume of water, was placed in a container and dispersed for 5 minutes using an ultrasonic disperser to remove air bubbles in the solution. 0.06 g of aluminum hydroxide-coated silica particles were added and suspended in this solution to prepare a sample solution for measurement.

[0132] The sample liquid was stirred at a speed of 6.67 s -1While stirring at 40°C, methanol was continuously added at a drop rate of 1.3 mL / min to settle the suspended aluminum hydroxide-coated silica particles and disperse them in the solvent. While methanol was being added dropwise, the transmitted light intensity of light with a wavelength of 780 nm through the sample liquid was measured to determine the transmittance, and a methanol drop transmittance curve was created. The methanol concentration [volume %] at which the transmittance was 50% was calculated as the hydrophobicity of the aluminum hydroxide-coated silica particles.

[0133] <Evaluation method for low-temperature fixability> The evaluation was carried out using a roller pressure type fixing prototype. The fixing temperature of the fixing unit was controlled using an external power source, and the paper was passed through at the desired temperature. The amount of the patch attached to the rear edge of the paper was 0.5±0.05mg / cm. 2 A solid patch was printed so that the thickness of the toner layer was 60 μm or less. A creep test was performed after the toner had passed through the fixing device, and it was determined that low-temperature offset did not occur if the toner layer peeled off from the fixing device was 60 μm or less. The minimum temperature at which low-temperature offset did not occur was determined. Note that "low-temperature offset" is defined as the toner not being fixed to the recording paper during fixing, but remaining attached to the fixing belt, and adhering to the recording paper after the fixing belt has made one revolution.

[0134] The temperature setting of the fixing roller was changed, and the temperature immediately adjacent to the paper passing section was monitored, and the paper was passed through at a specific time to perform fixing. The starting temperature was changed in 5°C increments from 120°C, and the result for Toner 4 was 145°C.

[0135] From the obtained results, the low temperature fixability was evaluated according to the following criteria. ◎ (Excellent): The minimum temperature is lower than that of the reference (toner of Production Example 4). Good: Equivalent to the reference. △ (Acceptable): The minimum temperature is 5°C or more higher than the reference. × (Not acceptable): The minimum temperature is 10°C or more higher than the reference.

[0136] <Method for evaluating heat resistance storage stability> The heat resistance storage stability (stability at high temperature storage) was evaluated based on the presence or absence of aggregates after high temperature storage. First, an evaluation sample was prepared that was left in a normal temperature and normal pressure environment (NN environment, 25°C, RH50%) and an evaluation sample that was left in a high temperature and high pressure environment (HH environment, 30°C, RH85%). Specifically, 20g of toner was weighed into a plastic container, the container was covered, and the container was brought into the above environment for 2 hours and allowed to acclimate to the environment. The container was then left for 12 hours with the cover opened. The container was then covered again and sealed to prepare an evaluation sample.

[0137] The evaluation sample was left at 50°C for 48 hours with the lid still on, and then the toner was taken out and sieved through a 75μm mesh sieve. The mass of the toner remaining on the sieve was measured, and the remaining rate, which is the ratio of this remaining amount to the total mass of the toner, [(amount of toner remaining after 48 hours) / (total mass of toner)×100] was calculated and evaluated according to the following criteria. The lower the remaining rate, the less blocking the toner caused.

[0138] The evaluation criteria for heat resistance storage stability are as follows. ◎ (Excellent): The remaining rate is less than 10%. ○ (Good): The remaining rate is between 10% and 20%. △ (Acceptable): The remaining rate is 20% or more but less than 30%. × (Fail): The remaining rate is 30% or more.

[0139] <How to evaluate fogging> A whiteness meter (model: ZE6000, manufactured by Nippon Denshoku Industries Co., Ltd.) was used to measure the whiteness of the non-image-forming areas after the continuous printing test, and the fogging was evaluated based on the difference from the whiteness of the paper before printing, which had been measured in advance, according to the following criteria. In the continuous printing test, printing was performed on 2,000 sheets of A4 paper with an image area of ​​20% (non-image area of ​​80%).

[0140] The whiteness was measured and fogging was evaluated for samples left overnight after a continuous printing test in a normal temperature and low humidity environment (NL environment, 25°C, 10% RH) and for samples left overnight after a continuous printing test in a high temperature and high humidity environment (HH environment, 30°C, 85% RH). The evaluation criteria for fogging are as follows: ◎ (Excellent): The difference in whiteness is less than 1.0. ◯ (Good): The difference in whiteness is 1.0 or more and less than 1.5. △(Acceptable): The difference in whiteness is 1.5 or more and less than 2.5. × (Fail): The difference in whiteness is 2.5 or more.

[0141] <Method of testing and evaluation of toner cartridge discharge performance> -Preparation of toner (HH) filled into toner cartridge for evaluation- The toner cartridge for evaluation was filled with toner according to the following procedure. First, the filling environment was a high temperature and humidity environment (HH environment, 30°C, RH85%), and the specified amount of toner was filled with the lid facing up. If the filling rate becomes too high, it will not be possible to fill it in one operation, but after filling, the cartridge is left to stand until the toner surface settles, and then the specified amount is filled by repeating the process of adding toner again. By doing this, if enough time is taken, it is possible to fill the cartridge to a filling rate of 100% or more.

[0142] After that, the toner cartridge filled with toner was left to stand for 30 minutes to allow the inside to settle, and then the lid was put back on, a waste toner box was attached, and the cartridge was sealed in an individual box. Next, the toner cartridge was returned to a horizontal position similar to the state in which it was used (as shown in Figures 4 and 5), and the toner cartridge was shaken again to stabilize the toner bias. After that, the toner cartridge was left to stand for 2 hours, and then placed in a thermostatic chamber at 50°C to give it a thermal history of 48 hours, and this was used as the toner cartridge filled toner for evaluation (HH).

[0143] -Preparation of toner (NN) filled into toner cartridge for evaluation- Two toner cartridges filled with toner were prepared in the same manner as described above in "Preparation of toner filled into toner cartridge for evaluation (HH)," except that the environment during filling was changed to a room temperature and normal pressure environment (NN environment, 25°C, RH 50%).

[0144] One of the toner cartridges was treated with heat in the same manner as in "Preparation of toner filled in toner cartridge for evaluation (HH)" above, to prepare toner filled in toner cartridge for evaluation (NN). The remaining toner cartridge was used to adjust the amount of toner falling in the discharge tester used in the discharge performance test.

[0145] - Toner cartridge discharge performance test carried out - The toner filled in the toner cartridge for evaluation thus prepared was attached to a discharge tester, and a toner discharge performance test (toner drop test) was carried out. In the toner discharge performance test, the toner discharge drive from the toner cartridge was an intermittent drive that repeated a 0.5 second discharge-on state and a 1.5 second discharge-off state. In addition, the rotation speed was adjusted using the above-mentioned "one remaining toner cartridge" that had no thermal history so that the drop amount in the stable region was about 7 g / min. Using the discharge tester adjusted in this way, the toner discharge performance (the performance of replenishing to the developing tank) of the toner cartridge for evaluation was evaluated according to the following evaluation criteria.

[0146] The evaluation criteria for toner discharge performance are as follows. ◎ (Excellent): The supply has been stable since the beginning of the test. ◯ (Good): The amount of replenishment fluctuates at the beginning of the test, but then stabilizes at the set value. △ (OK): Supply will be performed, but the amount will be less than the set value. × (Not possible): The toner cartridge is not replenished. (The toner cartridge locks up, or the replenishment does not continue.)

[0147] <Method of manufacturing aluminum hydroxide-coated silica particles to be used as an external additive> The aluminum hydroxide-coated silica particles used in the examples were prepared as follows. First, 5000 mL of ion-exchanged water and 500 g of hydrophilic fumed silica (manufactured by Tokuyama Corporation, product name: Reolosil) were mixed to obtain a silica dispersion. The obtained dispersion was heated to 45° C., and Al(OH) was added so that the pH became 6.0. 3 1000 mL of a sodium aluminate solution with a concentration of 500 g / L and a 5N aqueous solution of sodium hydroxide were added dropwise.

[0148] 0.5N diluted hydrochloric acid was added to the dispersion so that the pH of the dispersion became 3 to 4, and then 250 g of γ-aminopropyltriethoxysilane was added to the dispersion. Then, a 2N aqueous solution of sodium hydroxide was added to the dispersion so that the pH of the dispersion became 6.5. The obtained dispersion was filtered to obtain a wet cake. The obtained wet cake was washed with water and then dried to obtain a dried product 1.

[0149] The obtained dried product 1 was pulverized using an impact plate type jet pulverizer (manufactured by Japan Pneumatic Mfg. Co., Ltd., model: IJT-2) under a pulverization pressure of 0.6 MPa to obtain a pulverized product. 500 g of the pulverized product was added to a surface treatment solution obtained by adding and mixing 500 mL of n-hexane and 2.0 g of amino-modified silicone oil, and the mixture was stirred to obtain a mixed liquid. The mixture obtained was heated to 70°C, stirred, and dried in a reduced pressure dryer until the mass of the contents no longer decreased, obtaining a dried product 2.

[0150] The obtained dried product 2 was heated in an electric furnace at 160°C for 3 hours and cooled to obtain an aggregate of a composition of silica and aluminum hydroxide. The aggregate was pulverized using the above-mentioned collision plate type jet pulverizer under a pulverization pressure of 0.6 MPa to obtain "aluminum hydroxide-coated silica particles".

[0151] In accordance with the above-mentioned manufacturing method of "aluminum hydroxide-coated silica particles," external additives A to E and D1 to D4 were manufactured by changing the types and blending ratios of the raw materials used as shown in the following Table 1. In addition, external additive E was dispersed in a liquid during surface treatment, and then allowed to stand. The particles that settled quickly were classified according to the settling velocity, and these were collected as external additives F to G, respectively.

[0152] [Table 1]

[0153] <Toner Production> [Preparation of Toner 1] - Toner particle production (raw material mixing, kneading, pulverization, classification process) - The following raw materials were used to prepare the toner particles (toner cores). ·Binding resin Resin A: Amorphous polyester resin / 2000g mass molecular weight 1×10 3 ~1×10 4 Range distribution 76% Viscosity at 80°C measured with a flow tester: 8.8 x 10 4 Pa·s Resin B: Amorphous polyester resin / 500g mass molecular weight 1×10 4 ~1×10 5 Range distribution: 28% Main peak molecular weight: 6.6 x 10 3 Resin C: Amorphous polyester resin / 2500g mass molecular weight 1×10 5 Distribution above 6% Gel content 18% Coloring agents Carbon black (Mitsubishi Chemical Corporation, product name: #44) / 500g Release agent Release agent A: Paraffin wax (melting point 90°C, manufactured by Nippon Seiro Co., Ltd., product name: Fischer-Tropsch Wax FNP0090) / 86g Release agent B: Polypropylene wax (melting point 140°C, manufactured by Mitsui Chemicals, Inc., product name: NP-505) / 57g Charge control agent Potassium bis[benzylate(2-)-κ(2)O,O]borate(1-) (solubility in water 4.382g / L (20℃), Nippon Carlit Co., Ltd., product name: ion conductive material LR-147) / 50g

[0154] The above-mentioned raw materials for the toner particles were premixed for 5 minutes at a rotation speed of 1500 rpm using a Henschel mixer (manufactured by Nippon Coke and Engineering Co., Ltd., model: FM20C) [premixing step].

[0155] The resulting mixture was melt-kneaded in a twin-screw extruder (manufactured by Ikegai Corporation, model: PCM-30) at a cylinder set temperature of 110° C., a barrel rotation speed of 250 rpm, and a raw material supply rate of 10 kg / hour to obtain a melt-kneaded product.

[0156] The obtained molten kneaded product was cooled and solidified on a cooling belt, and then the solidified product was finely pulverized using a fluidized bed opposed jet mill (manufactured by Hosokawa Micron Corporation, model: Counter Jet Mill AFG) and classified (particle size adjustment) using a rotary (centrifugal airflow) type classifier (manufactured by Hosokawa Micron Corporation, model: TSP separator) to obtain toner particles. [Cooling and pulverization, classification process]

[0157] -External addition process- To the obtained toner particles, an external addition step was carried out in which aluminum hydroxide-coated silica particles prepared according to the above-mentioned "Method for preparing aluminum hydroxide-coated silica particles to be used as an external additive" were added as an external additive. In the external addition step of Production Example 1, the obtained toner particles and external additive A shown in Table 1 below were mixed using a Henschel mixer (manufactured by Nippon Coke and Engineering Co., Ltd., model: FM20C) at a rotation speed of 3000 rpm for 3 minutes to obtain toner 1 (external additive toner).

[0158] [Preparation of toners 2 to 20] Toners 2 to 20 were produced in the same manner as in "Preparation of Toner 1" except that the external additives in the external addition step were changed as shown in Table 2 below. Table 2 below shows the physical properties and blending ratios of the external additives and toner particles used in the preparation of each toner, as well as the physical properties of the toner.

[0159] [Table 2]

[0160] [Examples and Comparative Examples] - Toner cartridge filling process - The obtained toners 1 to 20 were filled into a toner cartridge according to the above-mentioned "Method of testing the discharge performance of a toner cartridge and its evaluation method" to obtain a toner cartridge for evaluation. As shown in the following Tables 3 to 6, a number of toner cartridges were prepared as the toner cartridge for evaluation, each with a toner bulk filling rate of 45%, 50%, 75%, 95%, and 100% relative to the volume of the toner filling tank of the toner cartridge.

[0161] [Table 3]

[0162] [Table 4]

[0163] [Table 5]

[0164] [Table 6]

[0165] Tables 3 to 6 show the results of the physical properties and discharge performance tests of the toner cartridges for evaluation in the examples and comparative examples. The toner cartridges used in the examples and comparative examples include a toner tank filled with toner and a discharge section that discharges the toner from the toner tank, and when the toner cartridge is attached to the image forming device, the discharge section is located above the toner tank, and a toner transport member provided in the toner tank rotates to transport the toner and discharge it from the discharge section, thereby replenishing the toner to the image forming device.

[0166] In Examples 1 to 80, the external additive contains aluminum hydroxide-coated silica particles, which are silica particles whose surfaces are coated with aluminum hydroxide, and the surfaces of the aluminum hydroxide-coated silica particles are hydrophobized. In Examples 1 to 80, the surface area ratio A is 0.6 to 5.9, and the amount of air P [μm] present per unit surface area of ​​the aluminum hydroxide-coated silica particles is 0.3 to 10. The toner cartridges of Examples 1 to 80 that satisfy these requirements are filled with toner that maintains low-temperature fixability, has excellent heat-resistant storage stability, and can suppress the occurrence of fogging, and can smoothly replenish toner even when subjected to high-temperature thermal history.

[0167] In contrast, in Comparative Examples 1 to 20 which did not satisfy these requirements, the evaluation results in at least one of the items of the toner's low temperature fixability, heat resistant storage stability and fogging, and the toner cartridge discharge performance test were inferior to those of the Examples. Note that the toners used in Comparative Examples 16 to 20 were rated as "x" for low temperature fixability, and therefore could not "maintain the low temperature fixability of the toner," one of the problems that the toner cartridge of the present disclosure is intended to solve, and therefore the discharge performance test was not performed, as shown in Table 6.

[0168] It can be seen that Examples 1 to 30 (Examples using Toners 1 to 6) in which the average primary particle diameter of the silica particles in the aluminum hydroxide-coated silica particles is 7 nm or more and 45 nm or less, are superior to Examples 31 to 35 (Examples using Toner 7) in which the average primary particle diameter exceeds the above upper limit, particularly in the evaluation of fogging in a high temperature and high humidity environment and the evaluation of the discharge performance test.

[0169] Examples 11 to 25 (examples using toners 3 to 5) in which the average primary particle diameter of the silica particles in the aluminum hydroxide-coated silica particles is 10 nm or more and 30 nm or less, and the thickness of the aluminum hydroxide coating layer is 0.15 nm or more and 0.4 nm or less, are superior in the evaluation of fogging, particularly in a room temperature and low humidity environment, compared to Examples 1 to 10 and 26 to 35 (examples using toners 1, 2, 6, and 7) in which the average primary particle diameter or coating layer thickness is outside the above ranges, and are also superior in the evaluation of the discharge performance test, whether the bulk filling rate of the toner relative to the volume of the toner filling tank of the toner cartridge is as high as 100% or as low as 45%.

[0170] Comparing Examples 41 to 45 (examples using toner 10 with external additive D3) and Examples 46 to 50 (examples using toner 11 with external additive D4) which have different thicknesses of the aluminum hydroxide coating layer, it can be seen that Examples 41 to 45, which have a coating layer thickness of 0.05 nm or more, have superior evaluation of fogging in a room temperature and low humidity environment than Examples 46 to 50, which have a coating layer thickness at the lower limit mentioned above.

[0171] It can be seen that Examples 56 to 70 (examples using toners 14 to 16) in which the surface area ratio A is 1.45 or more and 5.9 or less are particularly superior in the evaluation of heat resistance storage stability in a room temperature and normal pressure environment than Examples 51 to 55 (examples using toner 13) in which the surface area ratio A is below the above lower limit, and are particularly superior in the evaluation of low temperature fixability than Comparative Examples 11 to 20 (comparative examples using toners 17 and 20) in which the surface area ratio A exceeds the above upper limit.

[0172] It can be seen that Examples 11 to 15, etc. (Examples using Toner 3, etc.) in which the hydrophobicity of the aluminum hydroxide-coated silica particles is 45% or more and 85% or less are superior in evaluation of fogging, particularly in high-temperature, high-humidity environments, compared to Examples 36 to 40 (Examples using Toner 8) in which the hydrophobicity is below the above-mentioned lower limit, and are superior in evaluation of fogging in normal temperature, low humidity environments and high-temperature, high humidity environments compared to Examples 26 to 30 (Examples using Toner 6) in which the hydrophobicity exceeds the above-mentioned upper limit.

[0173] According to Examples 1 to 10, 26 to 35 (examples using toners 1, 2, 6 and 7), it is found that when the toner bulk filling rate relative to the volume of the toner filling tank of the toner cartridge is between 75% and 95%, the toner cartridge is evaluated as excellent in the discharge performance test; in other words, it is found that toner can be replenished more smoothly even when it is subjected to a high-temperature thermal history.

[0174] The embodiments disclosed herein are illustrative in all respects and are not intended to be limiting. Therefore, the technical scope of the present disclosure is not interpreted solely by the above-described embodiments, but is defined based on the claims. Also, all modifications within the scope and meaning equivalent to the claims are included.

[0175] For example, the configuration of the toner cartridge is not necessarily limited to the configuration of toner cartridge 100, and can be applied as long as the discharge section for discharging toner is located at the top of the toner filling tank and an area in which the toner is not agitated exists near or within this discharge section. [Explanation of symbols]

[0176] 1 Toner particles 1' Toner particles 2. Silica particles coated with aluminum hydroxide 21 Silica particles (silica substrate) 22 Aluminum hydroxide 2' Silica particles (not coated with aluminum hydroxide) 3 water molecules 100 toner cartridges 101 Case 102 Toner filling tank 103 Agitation Film 104 Film fixing part 105 Film Rotation Axis 106 Discharge screw 107 Exhaust port and shutter 110 Toner Pile 111 Areas where toner mixing is difficult 200 Developer tank 201 Developer holder 202 Developing sleeve 203 Agitating conveying screw 204 Supply Receiving Port 300 Photoreceptor

Claims

1. A toner cartridge that is detachable from an image forming apparatus, a toner tank filled with toner and a discharge unit that discharges the toner from the toner tank; when the toner cartridge is attached to the image forming apparatus, the discharge section is located above the toner tank, and the toner is transported by a rotational action of a toner transport member provided in the toner tank and discharged from the discharge section, thereby replenishing the toner to the image forming apparatus; The toner is a toner having an external additive attached to the surface of the toner particles, The external additive contains aluminum hydroxide-coated silica particles, which are silica particles whose surfaces are coated with aluminum hydroxide, The surfaces of the aluminum hydroxide-coated silica particles are subjected to a hydrophobic treatment, When the total surface area of ​​the aluminum hydroxide-coated silica particles attached to each toner particle is S(Al) and the surface area of ​​each toner particle is S(T), the surface area ratio A represented by the following formula (1) is 0.6 or more and 5.9 or less, A=S(Al) / S(T)...(1) A toner cartridge characterized in that the amount of air P [μm] present per unit surface area of ​​the aluminum hydroxide-coated silica particles, calculated by dividing the volume of air contained in the toner filling tank in which the toner is filled, by the total surface area of ​​the aluminum hydroxide-coated silica particles contained in the toner filling tank, is 0.3 or more and 10 or less.

2. 2. The toner cartridge according to claim 1, The toner cartridge according to claim 1, wherein the average primary particle diameter of the silica particles in the aluminum hydroxide-coated silica particles is 8 nm or more and 45 nm or less.

3. 2. The toner cartridge according to claim 1, The average primary particle diameter of the silica particles in the aluminum hydroxide-coated silica particles is 10 nm or more and 30 nm or less, A toner cartridge according to claim 1, wherein the thickness of the coating layer of aluminum hydroxide on said aluminum hydroxide-coated silica particles is 0.05 nm or more and 0.5 nm or less.

4. 4. The toner cartridge according to claim 1, The toner cartridge according to claim 1, wherein the surface area ratio A is equal to or greater than 1.45 and equal to or less than 5.

9.

5. 4. The toner cartridge according to claim 1, A toner cartridge, characterized in that the hydrophobicity of the aluminum hydroxide-coated silica particles is 45% or more and 85% or less.

6. 4. The toner cartridge according to claim 1, A toner cartridge, wherein a bulk filling rate of the toner with respect to a volume of the toner tank is 75% or more and 95% or less.

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