Toner, developer, toner storage unit, process cartridge, image forming apparatus, and image forming method

Abstract

To provide a toner that has a good manufacturing yield, and is excellent in transfer property, internal device contamination resistance, heat-resistance storage property, and low temperature fixability.SOLUTION: A toner according to the present invention is a toner containing a binder resin, an inorganic filler, and a crystalline polyester resin. When a particle cross section of the toner is observed to map constitutional elements including AL, Si, Fe, Ca, Mg, and Ti, which constitute the inorganic filler, the ratio of the number of particles having domains of any constitutional element of the inorganic filler with a maximum diameter of 2.0 μm or more is 10% or less of the total number of particles of the observed toner. The volume average particle diameter of the toner is 6.0 μm or less. The ratio of the volume average particle diameter to the number average particle diameter (volume average particle diameter / number average particle diameter) is 1.15 or less.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to toner, developer, toner storage unit, process cartridge, image forming apparatus, and image forming method. [Background technology]

[0002] Toner used in image forming apparatuses is required to reduce power consumption during fixing to conserve energy, and to enhance resistance to high temperatures and humidity during storage and transportation after manufacturing, thus requiring low-temperature fixing properties and heat-resistant storage properties. Furthermore, toner is required to have improved toner dispersion in order to reduce contamination inside the developing machine and other equipment used in image forming apparatuses, and to improve image quality.

[0003] As a toner that has low-temperature fixing properties and heat-resistant storage properties, and reduces in-machine contamination due to toner scattering, for example, an electrophotographic toner is disclosed that contains a styrene-acrylic resin and a crystalline resin as binder resins, and the crystalline resin contains a polyester resin portion obtained by polycondensation of raw material monomers containing an alcohol component and a carboxylic acid component that contain two types of aliphatic diols with different numbers of carbon atoms in predetermined proportions (see, for example, Patent Document 1).

[0004] In the electrophotographic toner described in Patent Document 1, a crystalline resin is finely dispersed and encapsulated in a styrene-acrylic resin, thereby achieving both low-temperature fixing properties and heat-resistant storage properties, while also improving the scratch resistance of the fixed image and reducing toner scattering. [Overview of the Initiative] [Problems that the invention aims to solve]

[0005] However, Patent Document 1 does not examine the transferability and particle size distribution of toner. The charge characteristics of toner used in general image forming apparatuses, such as electrophotographic toners, generally vary with particle size. Therefore, by narrowing the particle size distribution of toner, the charge distribution of toner particles is also narrowed, allowing for more ideal control of the toner within the image forming apparatus, thereby improving toner transferability and suppressing in-machine contamination.

[0006] Furthermore, toners generally contain inorganic compound fillers to improve low-temperature fixability and heat resistance. In this case, when using a manufacturing process that involves granulation in an aqueous medium, such as polymerization, the inorganic filler is dispersed in the resin solution. However, to improve dispersibility, a masterbatch containing the resin and inorganic filler is added to the resin solution. However, if the dispersion is insufficient, the inorganic filler may exist within the toner particles in an aggregated state of several micrometers, causing variations in charge properties and hardness among toner particles, making it difficult to control the toner particle size in the developing machine. This results in a broad toner particle size distribution and a broad charge distribution, leading to poor transferability and increased risk of contamination inside the printer.

[0007] Furthermore, toner particles larger than the target size can cause abnormal images, requiring removal through classification or sieving processes, which reduces manufacturing yield.

[0008] One aspect of the present invention aims to provide a toner that has good manufacturing yield and excellent transferability, resistance to in-machine contamination, heat resistance for storage, and low-temperature fixing properties. [Means for solving the problem]

[0009] One embodiment of the toner according to the present invention is: A toner containing a binder resin, an inorganic filler, and a crystalline polyester resin, Observing the particle cross-section of the toner, the inorganic filler is composed of A lWhen the constituent elements, including Si, Fe, Ca, Mg, and Ti, are mapped, the proportion of particles in which a domain exists where the maximum diameter of any of the constituent elements of the inorganic filler is 2.0 μm or more is 10% or less of the total number of particles of the observed toner. The volume-average particle size of the toner is 6.0 μm or less. The ratio of volume-average particle size to number-average particle size (volume-average particle size / number-average particle size) is 1.15 or less. [Effects of the Invention]

[0010] According to the present invention, it is possible to provide a toner with good manufacturing yield, excellent transferability, resistance to in-machine contamination, heat resistance for storage, and low-temperature fixing properties. [Brief explanation of the drawing]

[0011] [Figure 1] This figure shows an example of an EDX image of Al in a toner according to one embodiment. [Figure 2] This is a schematic diagram showing an example of an image forming apparatus according to one embodiment. [Figure 3] This is a schematic diagram showing another example of an image forming apparatus according to one embodiment. [Figure 4] This is a schematic diagram showing another example of an image forming apparatus according to one embodiment. [Figure 5] Figure 4 is a partially enlarged view of the image forming apparatus. [Figure 6] This is a schematic diagram showing an example of a process cartridge according to one embodiment. [Modes for carrying out the invention]

[0012] Embodiments of the present invention will be described in detail below. However, the embodiments are not limited by the following description and can be modified as appropriate without departing from the spirit of the invention. Furthermore, in this specification, the "~" indicating a numerical range means that the values ​​before and after it are included as the lower and upper limits, respectively, unless otherwise specified.

[0013] <Toner>

[0014] The state of existence of the inorganic filler in the toner according to one embodiment can be confirmed by embedding a sample of toner particles in an epoxy resin or the like, cutting it with a microtome or an ultramicrotome, and observing the cross-section of the toner with a scanning electron microscope (SEM) or the like. Further, a sample in which toner particles are embedded in an epoxy resin or the like may be cut with an ion beam using FIB-STEM (HD-2000, manufactured by Hitachi, Ltd.), and the cross-section of the toner may be observed.

[0015] The aggregation state of the inorganic filler in the toner according to one embodiment can be evaluated by using energy dispersive X-ray spectroscopy (EDX) to map the constituent elements including A, Si, Fe, Ca, Mg, and Ti that make up the inorganic filler and measuring the domain diameter of the inorganic filler. In this embodiment, it can be evaluated by EDX in the observation with a scanning electron microscope (SEM). l l

[0016] (Measurement of the domain diameter of the inorganic filler in toner particles) Fix the toner on carbon tape and observe the sample coated with carbon for charge-up prevention with SEM and EDX. The observation conditions are as follows: using the SEM of SU8230 manufactured by Hitachi and the EDX XFLash FLatQUAD 5060F manufactured by Bruker, at an acceleration voltage of 3 to 10 kV (select an appropriate voltage depending on the filler type), a magnification of 4000 times, and obtain an EDX image of any one of the constituent elements of the inorganic filler used in the toner production for 20 or more toner particles. Edit this detection image of the element on image editing software (A Image-kun manufactured by Asahi Kasei Engineering).

[0017] - Scale setting - From the "Image Input / Output" tab, load the image to be analyzed, and then use the "New Scale Setting" button to set the scale for this image based on the scale bar in the image.

[0018] -Image Processing- For color images, select "Color Image Analysis" from the "Image Analysis" tab, perform the appropriate conversion, select the image with the clearest contrast, and convert it to a black and white image. Then, select the "Laplacian Filter" process from the "Image Quality Improvement" tab to enhance the image edges and reduce blur.

[0019] -Calculation of inorganic filler domain diameter- [Image processing] Select "Particle Analysis" from the "Image Analysis" tab. Select "Manual" for the binarization method and correction method, set the small shape removal area appropriately so that small particles are not removed, and press the "Execute" button. Determine an appropriate threshold while comparing with the original image and perform binarization. If, in the binarized image, multiple particles are determined to be one particle, manually correct them while comparing with the original image and press the "Finish" button. From the obtained results, determine the maximum diameter for each domain of inorganic filler within a single toner particle, count the number of toner particles in which the maximum diameter of any constituent element of the inorganic filler is 2.0 μm or more, and determine whether the proportion of toner particles in which domains with a maximum diameter of 2.0 μm or more are present is 10% or less of the total number of observed particles. For example, Figure 1 shows an example of an EDX image of Al in toner according to one embodiment. Note that the lines in Figure 1 indicate the outer shape of the toner particle.

[0020] In this embodiment, the toner, crystalline polyester resin, and amorphous polyester according to one embodiment, as well as the endothermic peak temperature and endothermic shoulder temperature of the toner, can be measured, for example, using a DSC system (differential scanning calorimeter) ("DSC-60", manufactured by Shimadzu Corporation).

[0021] Specifically, the endothermic shoulder 1, endothermic peak, and endothermic shoulder 2 of the target sample can be measured by the following procedure. First, approximately 5.0 mg of polyester resin is placed in an aluminum sample container, the sample container is placed on a holder unit, and the container is set in an electric furnace. Next, under a nitrogen atmosphere, it is heated from 0°C to 150°C at a heating rate of 10°C / min. After that, it is cooled from 150°C to 0°C at a cooling rate of 10°C / min, and then heated again to 150°C at a heating rate of 10°C / min, and the DSC curve is measured using a differential scanning calorimeter ("DSC-60", manufactured by Shimadzu Corporation). From the obtained DSC curves, using the analysis program in the DSC-60 system, the DSC curve for the first heating cycle can be selected, and the endothermic shoulder 1 and endothermic shoulder 2 for the first heating cycle of the target sample can be determined using the "endothermic shoulder temperature" in the analysis program. Similarly, the DSC curve for the second heating cycle can be selected, and the endothermic shoulder 1 and endothermic shoulder 2 for the second heating cycle of the target sample can be determined using the "endothermic shoulder temperature" in the analysis program. Shoulder temperatures are defined as endothermic shoulder 1, endothermic shoulder 2, etc., in order from the lowest temperature. Furthermore, from the obtained DSC curves, using the analysis program in the DSC-60 system, the endothermic peak for the first heating cycle can be selected, and the endothermic peak for the first heating cycle of the target sample can be determined, and the DSC curve for the second heating cycle can be selected, and the endothermic peak for the second heating cycle of the target sample can be determined using the "endothermic peak temperature" in the analysis program.

[0022] Regarding the shape and size of the toner, it is preferable that it has the following characteristics: volume-average particle size, ratio of volume-average particle size to number-average particle size (volume-average particle size / number-average particle size), average circularity, etc.

[0023] The volume-average particle size of the toner is preferably 6.0 μm or less, and more preferably 4.0 μm to 5.5 μm. When the volume-average particle size is 4 μm or more, the toner is less likely to fuse to the surface of the carrier during long-term agitation in the developing device in a two-component developer, and the charging capacity of the carrier can be maintained. When it is 6 μm or less, high-resolution, high-quality images can be obtained, and fluctuations in the toner particle size are suppressed when the toner in the developer is balanced.

[0024] In one embodiment of the toner, the ratio of volume-average particle size to number-average particle size (volume-average particle size / number-average particle size) is preferably 1.00 to 1.15, and more preferably 1.10 to 1.13. The volume-average particle size and the ratio of volume-average particle size to number-average particle size (volume-average particle size / number-average particle size) can be measured using a particle size analyzer ("Multisizer III", manufactured by Beckman Coulter) at an aperture diameter of 100 μm, and analyzed using analysis software (Beckman CoulterMutLisizer 3 Version 3.51).

[0025] For example, 0.5 mL of a 10% by mass aqueous solution of surfactant (alkylbenzene sulfonate, Neogen SC-A, manufactured by Daiichi Kogyo Seiyaku Co., Ltd.) is added to a 100 mL glass beaker, 0.5 g of each toner is added and stirred with a micro spatula, and then 80 mL of deionized water is added. The resulting dispersion is dispersed using an ultrasonic disperser (W-113MK-II, manufactured by Honda Electronics Co., Ltd.) for 10 minutes. The dispersion can be measured using a Multisizer III, and an Isoton III (manufactured by Beckman Coulter) can be used as the measurement solution.

[0026] The measurement is performed by dropping the toner sample dispersion until the concentration indicated by the device reaches 8±2%. For this measurement method, it is important to maintain a concentration of (8±2)% in order to ensure reproducibility of particle size measurements. Within this concentration range, no error will occur in particle size.

[0027] The acid value of the toner according to one embodiment is preferably 10 mg KOH / g to 30 mg KOH / g, more preferably 13 mg KOH / g to 25 mg KOH / g, and even more preferably 15 mg KOH / g to 20 mg KOH / g. When the acid value of the toner according to one embodiment is within the above preferred range, the particle size distribution of the toner can be further narrowed from 1.15, so the toner according to one embodiment can have a sharper particle size distribution. The acid value of the toner according to one embodiment can be adjusted by the acid value of the binder resin and crystalline polyester resin and the blending ratio of the resins. The blending ratio of these resins is determined by using binder resins and crystalline polyester resins with high acid values ​​so that the acid value of the toner according to one embodiment is 10 mg KOH / g to 30 mg KOH / g. As a result, the toner particles can be granulated so that the particle size distribution is narrower, so the particle size distribution of the toner according to one embodiment that is finally obtained can be sharper. The reason why the particle size distribution of toner can be made sharper is thought to be that increasing the acid value of the resins that make up the toner increases the reactivity of the resin molecule ends, making it easier to refine the oil phase containing various resins dispersed in the aqueous medium during toner manufacturing, and thus enabling the granulation of toner particles with small particle size and a sharp particle size distribution.

[0028] In this embodiment, the acid value is measured using a method compliant with JIS K0070-1992.

[0029] Specifically, first, 0.5 g of the sample (0.3 g of the ethyl acetate-soluble portion) is added to 120 mL of toluene and dissolved by stirring at 23°C for approximately 10 hours. Next, 30 mL of ethanol is added to prepare the sample solution. If the sample does not dissolve, solvents such as dioxane or tetrahydrofuran are used. Furthermore, the acid value is measured at 23°C using a potentiometric automatic titrator (DL-53 Titrator, Mettler-Toledo) and an electrode (DG113-SC, Mettler-Toledo), and the analysis is performed using the analysis software LabX Light Version 1.00.000.

[0030] For calibration of the instrument, a mixed solvent of 120 mL of toluene and 30 mL of ethanol is used. The measurement conditions are the same as for hydroxyl value.

[0031] The acid value can be measured as described above. Specifically, it is measured by titrating with a pre-standardized 0.1N potassium hydroxide / alcohol solution, and the acid value is calculated from the titration volume using the formula: Acid value [mgKOH / g] = Titration volume [mL] × N × 56.1 [mg / mL] / Sample weight [g] (where N is the factor for the 0.1N potassium hydroxide / alcohol solution).

[0032] Average circularity is the average value of the circularity obtained by dividing the perimeter of an equivalent circle with the same shape and projected area as the toner by the perimeter of the toner's projected image. For example, 0.950 to 0.980 is preferred, and 0.960 to 0.975 is more preferred. It is preferable that particles with an average circularity of less than 0.950 account for 15.0 percent or less.

[0033] An average circularity of 0.950 or higher ensures satisfactory transferability and high-quality images free of dust. An average circularity of 0.980 or lower prevents cleaning defects on the photoreceptor and transfer belt in image forming systems employing blade cleaning, preventing image contamination. For example, in image forming with a high image area ratio, such as photographic images, toner that has formed an untransferred image due to paper feeding problems accumulates on the photoreceptor as residual toner, resulting in background contamination. Furthermore, it prevents contamination of charging rollers and other components that contact charge the photoreceptor, allowing them to perform at their full charging capacity.

[0034] The average circularity can be measured using a flow-type particle image analyzer ("FPIA-2100", manufactured by Sysmex Corporation) and analyzed using analysis software (FPIA-2100 Data Processing Program for FPIA version 00-10).

[0035] To give a specific example, 0.1 to 0.5 mL of a 10% by mass aqueous solution of surfactant (alkylbenzene sulfonate, Neogen SC-A, manufactured by Daiichi Kogyo Seiyaku Co., Ltd.) is added to a 100 mL glass beaker, 0.1 to 0.5 g of each toner is added and stirred with a micro spatula, and then 80 mL of deionized water is added. The resulting dispersion is dispersed using an ultrasonic disperser (manufactured by Honda Electronics Co., Ltd.) for 3 minutes. The shape and distribution of the toner are measured using an FPIA-2100 until a concentration of 5,000 to 15,000 particles / μL is obtained.

[0036] For this measurement method, it is important to set the dispersion concentration to 5,000 to 15,000 particles / μL in order to ensure reproducibility of the average circularity measurement. To obtain the desired dispersion concentration, it is necessary to change the conditions of the dispersion, namely the amount of surfactant added and the amount of toner. The amount of surfactant required varies depending on the hydrophobicity of the toner, similar to the measurement of toner particle size mentioned above. Adding too much surfactant will generate noise due to bubbles, while adding too little will not adequately wet the toner, resulting in insufficient dispersion. The amount of toner to add also varies depending on the particle size; less is needed for small particles and more for large particles. For toner particles of 3 μm to 10 μm, adding 0.1 g to 0.5 g of toner can adjust the dispersion concentration to 5,000 to 15,000 particles / μL.

[0037] A binder resin, an inorganic filler, and a crystalline polyester resin included in a toner according to one embodiment will be described.

[0038] [Binding resin] The binder resin used in this embodiment includes a polyester resin and an inorganic filler.

[0039] (Polyester resin) Polyester resins include crystalline polyester resins and amorphous (non-crystalline) polyester resins.

[0040] ((Crystalline polyester resin)) Examples of crystalline polyester resins include, but are not limited to, crystalline polyester resins having a structure represented by the following general formula (1), synthesized using, for example, a material containing 80 mol% or more, preferably 85 to 100 mol%, of a diol compound having 2 to 6 carbon atoms, particularly 1,4-butanediol, 1,6-hexanediol, and their derivatives, as an alcohol component, and fumaric acid, a carboxylic acid having a double bond (C=C bond), and their derivatives as an acidic component. [-O-CO-(CR1=CR2)L-CO-O-(CH2)m-]n General formula (1) (Here, L is an integer between 1 and 3, and m and n are the number of repeating units. R1 and R2 are hydrogen atoms or hydrocarbon groups, and may be the same or different.)

[0041] Furthermore, methods for controlling the crystallinity and softening point of crystalline polyester resins include designing and using nonlinear polyester resins that are produced by condensation polymerization in which a trivalent or higher polyhydric alcohol such as glycerin is added to the alcohol component during polyester synthesis, or a trivalent or higher polycarboxylic acid such as trimellitic anhydride is added to the acid component.

[0042] The molecular structure of crystalline polyester resins can be determined by NMR measurements in solution and solid state, as well as by X-ray diffraction, GC / MS, LC / MS, IR measurements, etc. However, a simple method is to use infrared absorption spectroscopy, which is 965±10 cm⁻¹. -1 or 990±10cm -1 Examples include those that have absorption based on δCH (out-of-plane bending vibration) of olefins.

[0043] Regarding molecular weight, after careful consideration from the viewpoint that a sharp molecular weight distribution and low molecular weight exhibit excellent low-temperature fixation, it was found that, in the molecular weight distribution of the soluble components of o-dichlorobenzene determined by GPC, the peak position in the molecular weight distribution graph, where the horizontal axis is Log(M) and the vertical axis is weight%, is in the range of 3.5 to 4.0, the full width at half maximum of the peak is 1.5 or less, the weight-average molecular weight (Mw) is 1000 to 30000, the number-average molecular weight (Mn) is 500 to 6000, and the ratio of weight-average molecular weight (Mw) to number-average molecular weight (Mn) (Mw / Mn) is 2 to 10 is preferable.

[0044] The melting temperature and F1 / 2 temperature should preferably be low enough so as not to degrade the heat-resistant storage properties, and preferably the DSC endothermic peak temperature is 50°C to 130°C. When the DSC endothermic peak temperature is 50°C or higher, heat-resistant storage properties can be achieved, and blocking is suppressed at the temperature inside the developing device. When it is 130°C or lower, the rise in the lower limit temperature for fixing is suppressed, allowing for low-temperature fixing properties. By setting the F1 / 2 temperature to 120°C to 135°C, both separation properties during fixing and low-temperature fixing properties can be achieved. When the F1 / 2 temperature is 120°C or higher, the deterioration of the toner's thermal properties during fixing is suppressed, and separation properties can be achieved. When the F1 / 2 temperature is 135°C or lower, the rise in the toner softening start temperature is suppressed, and low-temperature fixing properties can be obtained.

[0045] The content of crystalline polyester resin in relation to the toner is preferably 1% to 20% by mass, and particularly preferably 3% to 15% by mass. If the content is 1% by mass or more, it is easily fixed at low temperatures, and if it is 20% by mass or less, filming on the photoreceptor is less likely to occur, and image quality can be maintained.

[0046] From the viewpoint of affinity between paper and resin, the acid value of the crystalline polyester resin is preferably between 10 mg KOH / g and 40 mg KOH / g. If the acid value of the crystalline polyester resin is 10 mg KOH / g or higher, the desired low-temperature fixation properties can be achieved, and if it is 40 mg KOH / g or lower, the hot offset properties can be improved.

[0047] Crystalline polyester resins exhibit thermal melting characteristics, showing a rapid decrease in viscosity near the fixing initiation temperature, due to their crystalline nature. This means that they have good heat resistance and storage properties due to their crystalline structure until just before the melting initiation temperature, at which point they undergo a rapid decrease in viscosity (sharp melting) and fix. Therefore, it is possible to design toners that combine good heat resistance and low-temperature fixing properties. Furthermore, it was found that they also show favorable results regarding the release width (the difference between the fixing lower limit temperature and the hot offset occurrence temperature).

[0048] ((Amorphous polyester resin)) Amorphous polyester resins are obtained using a polyhydric alcohol component and a polyhydric carboxylic acid component such as a polyhydric carboxylic acid, a polyhydric carboxylic acid anhydride, or a polyhydric carboxylic acid ester.

[0049] In this embodiment, amorphous polyester resin refers to a resin obtained using a polyhydric alcohol component and a polyhydric carboxylic acid component such as a polyhydric carboxylic acid, polyhydric carboxylic acid anhydride, or polyhydric carboxylic acid ester, as described above. Modified polyester resins, such as the prepolymers described later, and resins obtained by crosslinking and / or stretching the prepolymers, do not belong to the category of amorphous polyester resin.

[0050] Examples of polyhydric alcohol components include alkylene (2-3 carbon atoms) oxide (average number of added moles 1-10) adducts of bisphenol A such as polyoxypropylene(2,2)-2,2-bis(4-hydroxyphenyl)propane and polyoxyethylene(2,2)-2,2-bis(4-hydroxyphenyl)propane; ethylene glycol, propylene glycol, neopentyl glycol, glycerin, pentaerythritol, trimethylolpropane, hydrogenated bisphenol A, sorbitol, or their alkylene (2-3 carbon atoms) oxide (average number of added moles 1-10) adducts. These may be used individually or in combination of two or more.

[0051] Examples of polycarboxylic acid components include dicarboxylic acids such as adipic acid, phthalic acid, isophthalic acid, terephthalic acid, fumaric acid, and maleic acid; succinic acids substituted with C1-C20 alkyl groups or C2-C20 alkenyl groups, such as dodecenyl succinic acid and octyl succinic acid; trimellitic acid and pyromellitic acid; anhydrides of these acids and alkyl (C1-C8) esters of these acids. These may be used individually or in combination of two or more.

[0052] It is preferable that the amorphous polyester resin, the prepolymer described later, and the resin obtained by crosslinking and / or stretching the prepolymer are at least partially compatible. This compatibility improves low-temperature fixation and high-temperature offset resistance. For this reason, it is preferable that the polyhydric alcohol component and polyhydric carboxylic acid component constituting the amorphous polyester resin and the polyhydric alcohol component and polyhydric carboxylic acid component constituting the prepolymer described later have similar compositions.

[0053] There are no particular restrictions on the molecular weight of the amorphous polyester resin, and it can be appropriately selected according to the purpose. If the molecular weight is too low, the toner may have poor heat resistance during storage and poor durability against stress such as agitation in the developer. If the molecular weight is too high, the viscoelasticity of the toner during melting may increase, resulting in poor low-temperature fixation. In GPC measurement, it is preferable that the weight-average molecular weight (Mw) is 2,500 to 10,000, the number-average molecular weight (Mn) is 1,000 to 4,000, and the ratio of weight-average molecular weight (Mw) to number-average molecular weight (Mn) (Mw / Mn) is 1.0 to 4.0.

[0054] There are no particular restrictions on the acid value of the amorphous polyester resin, and it can be appropriately selected depending on the purpose, but 1 mg KOH / g to 40 mg KOH / g is preferred, and 15 mg KOH / g to 40 mg KOH / g is more preferred. When the acid value is 1 mg KOH / g or higher, the toner tends to become negatively charged, and furthermore, the affinity between the paper and the toner improves when fixing to paper, and the low-temperature fixing performance can be improved. When the acid value is 40 mg KOH / g or lower, the electrostatic stability, especially the electrostatic stability against environmental fluctuations, does not decrease.

[0055] There are no particular restrictions on the hydroxyl value of amorphous polyester resin, and it can be appropriately selected depending on the purpose, but it is preferable to have a value of 5 mg KOH / g or higher.

[0056] There are no particular restrictions on the glass transition temperature (Tg) of amorphous polyester resin, and it can be appropriately selected according to the purpose. If the Tg is too low, the toner may have poor heat resistance for storage and poor durability against stress such as agitation in the developer. If the Tg is too high, the viscoelasticity of the toner during melting may increase, resulting in poor low-temperature fixing performance. Therefore, the glass transition temperature Tg of amorphous polyester resin is preferably 40°C to 70°C, and more preferably 45°C to 60°C. If the glass transition temperature is 40°C or higher, stable heat resistance for storage can be achieved, and if it is 70°C or lower, stable low-temperature fixing performance can be achieved.

[0057] There are no particular restrictions on the content of amorphous polyester resin, and it can be appropriately selected depending on the purpose, but 50 to 95 parts by mass, and more preferably 60 to 90 parts by mass, per 100 parts by mass of toner. If the content of amorphous polyester resin is less than 50 parts by mass, the dispersibility of the pigment and release agent in the toner deteriorates, which may easily cause image blurring and distortion. If the content of amorphous polyester resin exceeds 95 parts by mass, the content of crystalline polyester decreases, which may result in poor low-temperature fixing performance. A more preferable range for the amorphous polyester resin content is advantageous in that it is superior in all aspects: high image quality, high stability, and low-temperature fixing performance.

[0058] The molecular structure of amorphous polyester resins can be determined by NMR measurements in solution and solid state, as well as by X-ray diffraction, GC / MS, LC / MS, and IR measurements. A simple method is infrared absorption spectroscopy, which can be used to determine the molecular structure at 965±10 cm⁻¹. -1 and 990±10cm -1 One method for detecting amorphous polyester resins is one in which those that do not exhibit absorption based on δCH (out-of-plane angular bending vibration) of olefins are identified.

[0059] ((Unmodified polyester resin)) The polyester resin may include an amorphous, unmodified polyester resin.

[0060] It is preferable that the modified polyester resin, obtained by crosslinking and / or stretching a binder resin precursor consisting of an unmodified polyester resin and a modified polyester resin, is at least partially compatible. This improves low-temperature fixability and hot offset resistance. For this reason, it is preferable that the polyols and polycarboxylic acids of the modified polyester resin and the unmodified polyester resin have similar compositions. Furthermore, as the unmodified polyester resin, an amorphous polyester resin used in a crystalline polyester dispersion can also be used if it is unmodified.

[0061] The acid value of unmodified polyester resin is typically between 1 mg KOH / g and 40 mg KOH / g, with 15 mg KOH / g and 30 mg KOH / g being preferred. When the acid value is 1 mg KOH / g or higher, the toner tends to become negatively charged, and furthermore, the affinity between the paper and the toner improves during fixing to paper, thereby improving low-temperature fixing performance. When the acid value is 40 mg KOH / g or lower, the decrease in electrostatic stability, especially the decrease in electrostatic stability due to environmental fluctuations, is suppressed.

[0062] The hydroxyl value of the unmodified polyester resin is preferably 5 mg KOH / g or higher. The hydroxyl value is measured using a method compliant with JIS K0070-1966. Specifically, first, 0.5 g of the sample is accurately weighed into a 100 mL volumetric flask, and 5 mL of acetylation reagent is added to it. Next, the flask is heated in a 100 ± 5 °C bath for 1 to 2 hours, then removed from the bath and allowed to cool. Water is then added and shaken to decompose the acetic anhydride. Next, to completely decompose the acetic anhydride, the flask is heated again in a bath for 10 minutes or more, allowed to cool, and then the flask walls are thoroughly washed with an organic solvent. Finally, the hydroxyl value is measured at 23 °C using a potentiometric automatic titrator DL-53 Titrator (Mettler-Toledo) and electrode DG113-SC (Mettler-Toledo), and the analysis is performed using the analysis software LabX Light Version 1.00.000. For calibration of the device, a mixed solvent of 120 mL of toluene and 30 mL of ethanol is used. The measurement conditions are as follows:

[0063] [Measurement conditions] • Stirring Speed[%]:25 Time[s]:15 ·EV titration curve (EQP titration) Titrant / Sensor Title:CH3ONa Concentration[moL / L]:0.1 Sensor: DG115 Unit of measurement: mV Predispensing to volume Volume [mL]: 1.0 Wait time[s]:0 Titrant addition: Dynamic dE(set)[mV]:8.0 dV(min)[mL]:0.03 dV(max)[mL]:0.5 Measure mode:EquiLibrium controLLed dE[mV]:0.5 dt[s]:1.0 t(min)[s]:2.0 t(max)[s]:20.0 Recognition ThreshoLd:100.0 Steepest jump: only No Range: No Tendency: None Termination At maximum volume [mL]: 10.0 at potentiaL:No at sLope: No after number EQPs: Yes n=1 comb.termination conditions:No EvaLuation Procedure: Standard PotentiaL1:No PotentiaL2:No Stop for reevaLuation: No

[0064] In this embodiment, the binder resin component contained in the oil phase may be a combination of crystalline polyester resin, amorphous polyester resin, binder resin precursor, and unmodified polyester resin, but it may also contain binder resin components other than these resins. The binder resin component preferably contains polyester resin, and more preferably contains 50% by weight or more of polyester resin. If the polyester resin content is less than 50% by weight, the low-temperature fixation performance may decrease. It is particularly preferable that all of the binder resin components are polyester resins.

[0065] Other binder resin components besides polyester resin include polymers of styrene or styrene-substituted materials such as polystyrene, poly(p-chlorostyrene), and polyvinyltoluene; styrene-p-chlorostyrene copolymer, styrene-propylene copolymer, styrene-vinyltoluene copolymer, styrene-vinylnaphthalene copolymer, styrene-methyl acrylate copolymer, styrene-ethyl acrylate copolymer, styrene-butyl acrylate copolymer, styrene-octyl acrylate copolymer, styrene-methyl methacrylate copolymer, styrene-ethyl methacrylate copolymer, styrene-butyl methacrylate copolymer, styrene-α-chloromethacrylate copolymer, and styrene-acrylic Examples include styrene copolymers such as nitrile copolymers, styrene-vinyl methyl ketone copolymers, styrene-butadiene copolymers, styrene-isoprene copolymers, styrene-acrylonitrile-indene copolymers, styrene-maleic acid copolymers, and styrene-maleic acid ester copolymers; polymethyl methacrylate, polybutyl methacrylate, polyvinyl chloride, polyvinyl acetate, polyethylene, polypropylene, epoxy resins, epoxy polyol resins, polyurethane resins, polyamide resins, polyvinyl butyral, polyacrylic acid resins, rosin, modified rosin, terpene resins, aliphatic or alicyclic hydrocarbon resins, aromatic petroleum resins, chlorinated paraffin, and paraffin wax.

[0066] (Inorganic filler) There are no particular restrictions on the inorganic fillers, and they can be appropriately selected depending on the purpose. Examples include smectite group clay minerals (montmorillonite, saponite, hectorite, etc.), kaolin group clay minerals (kaolinite, etc.), bentonite, attapulgite, magadhiite, and kanemite, which are inorganic layered compounds. These may be used individually or in combination of two or more.

[0067] ((Organic modification of inorganic fillers)) By organically modifying the inorganic filler, it exhibits good dispersibility in the oil phase where the binder resin is dissolved in an organic solvent, even though it is an inorganic compound. This eliminates the need for the process of masterbatching the inorganic filler with resin, which is generally done to improve dispersibility in resin solutions.

[0068] Organically modified inorganic fillers are layered inorganic fillers in which at least some of the ions present between the layers of a layered inorganic filler are modified with organic ions. Layered inorganic fillers are layered inorganic fillers formed by stacking layers with a thickness of several nanometers. "Modified" is synonymous with introducing organic ions into the ions present between the layers of a layered inorganic filler, and in a broad sense, it is intercalation.

[0069] ((Effect of inorganic fillers)) Layered inorganic fillers exert their greatest effect when positioned near the surface and are therefore easily positioned near the surface. Furthermore, it is preferable that organically modified layered inorganic fillers are contained in toner particles in a uniform proportion regardless of the size of the toner particle. This results in, for example, a lower content of organically modified layered inorganic fillers in toner particles with a small particle size. As a result, the proportion of organically modified layered inorganic fillers positioned on the surface decreases, the surface of the toner particles becomes relatively softer, and external additives added to the toner matrix become easier to embed. This has the effect of avoiding phenomena such as the inhibition of the detachment of external additives, which are advantageous for imparting toner fluidity, and improving heat resistance during storage.

[0070] There are no particular restrictions on the organically modified layered inorganic filler, and it can be appropriately selected according to the purpose. For example, organically modified layered inorganic fillers in which at least some of the ions present between the layers of these layered inorganic fillers are modified with organic ions can be used. Among these, those in which at least some of the ions between the layers of smectite group clay minerals having a smectite-based basic crystal structure are modified with organic cations are preferred from the viewpoint of dispersion stability near the toner surface, and those in which at least some of the ions between the layers of montmorillonite are modified with organic cations, and those in which at least some of the ions between the layers of bentonite are modified with organic cations are particularly preferred.

[0071] The fact that organically modified layered inorganic fillers have at least some of the ions present between the layers of the layered inorganic filler modified by organic ions can be confirmed by gas chromatography-mass spectrometry (GCMS). For example, a preferred method involves dissolving the binder resin in the toner sample in a solvent, filtering the resulting solution, thermally decomposing the obtained solid in a pyrolysis apparatus, and identifying the structure of the organic matter by GCMS. Specifically, a method using a Py-2020D (manufactured by Frontier Labs) as the pyrolysis apparatus, performing thermal decomposition at 550°C, and then identifying the organic matter using a GCMS instrument QP5000 (manufactured by Shimadzu Corporation) is recommended.

[0072] Furthermore, examples of organically modified layered inorganic fillers include layered inorganic compounds obtained by introducing metal anions by substituting a portion of the divalent metal in the layered inorganic filler with a trivalent metal, and further modifying at least a portion of the metal anions with organic anions.

[0073] Commercially available organically modified layered inorganic fillers can be used. Examples of such commercially available products include quaternium-18 bentonite such as Bentone 3, Bentone 38, Bentone 38V (all manufactured by ELementis Specialties), Thixogel VP (manufactured by United CataLyst), Kraton 34, Kraton 40, Kraton XL (all manufactured by Southern Clay); stearalkonium bentonite such as Bentone 27 (manufactured by Rheox), Thixogel LG (manufactured by BYK Additives & Instruments), Kraton AF, Kraton APA (all manufactured by BYK Additives & Instruments); quaternium-18 / benzalkonium bentonite such as Kraton HT, Kraton PS (both manufactured by Southern Clay); organically modified montmorillonite such as Kraton HY (manufactured by Southern Clay); and organically modified sucmetite such as Lucentite SPN (manufactured by Coop Chemical). Among these, Clayton AF and Clayton APA are particularly preferred.

[0074] Furthermore, as an organically modified layered inorganic filler, DHT-4A (manufactured by Kyowa Chemical Industry Co., Ltd.) is particularly preferred if it is modified with a compound having an organic ion represented as R1(OR2)nOSO3M (where R1 is an alkyl group with 13 carbon atoms, R2 is an alkylene group with 2 to 6 carbon atoms, n is an integer from 2 to 10, and M represents a monovalent metal element). Examples of compounds having an organic ion represented as R1(OR2)nOSO3M include Hythenol 330T (manufactured by Daiichi Kogyo Seiyaku Co., Ltd.).

[0075] The content of the organically modified layered inorganic filler relative to the toner is preferably 0.1% to 3.0% by mass, and particularly preferably 0.3% to 1.5% by mass. If the content is less than 0.1% by mass, the effect of the layered inorganic filler becomes difficult to exert, and if it exceeds 3.0% by mass, it tends to inhibit low-temperature fixation.

[0076] The organic ion modifier, which is a compound having organic ions and capable of modifying at least some of the ions present between the layers of a layered inorganic filler into organic ions, is not particularly limited and can be appropriately selected depending on the purpose. Examples include quaternary alkylammonium salts, phosphonium salts, imidazolium salts; branched, unbranched, or cyclic alkyls having 1 to 44 carbon atoms; branched, unbranched, or cyclic alkenyls having 1 to 22 carbon atoms; branched, unbranched, or cyclic alkoxys having 8 to 32 carbon atoms; branched, unbranched, or cyclic hydroxyalkyls having 2 to 22 carbon atoms; sulfates having a skeleton such as ethylene oxide or propylene oxide; sulfonates having a skeleton; carboxylates having a skeleton; phosphates having a skeleton. Among these, quaternary alkylammonium salts and carboxylic acids having an ethylene oxide skeleton are preferred, and quaternary alkylammonium salts are particularly preferred. These may be used individually or in combination of two or more.

[0077] Examples of quaternary alkylammonium compounds include trimethylstearylammonium, dimethylstearylbenzylammonium, dimethyloctadecylammonium, and oleylbis(2-hydroxyethyl)methylammonium.

[0078] (Binding resin precursor) The binder resin preferably contains a binder resin precursor.

[0079] Preferably, the binder resin precursor is a modified polyester resin, and examples include polyester prepolymers modified with isocyanates or epoxy. These react with compounds containing active hydrogen groups (amines, etc.) to extend and improve the release width (the difference between the fixing limit temperature and the hot offset generation temperature). This polyester prepolymer can be easily synthesized by reacting a base polyester resin with conventionally known isocyanating agents or epoxidizing agents. Examples of isocyanating agents include aliphatic polyisocyanates (tetramethylene diisocyanate, hexamethylene diisocyanate, 2,6-diisocyanatomethylcaproate, etc.); alicyclic polyisocyanates (isophorone diisocyanate, cyclohexylmethane diisocyanate, etc.); aromatic diisocyanates (tole diisocyanate, diphenylmethane diisocyanate, etc.); aromatic aliphatic diisocyanates (α,α,α',α'-tetramethylxylylene diisocyanate, etc.); isocyanurates; polyisocyanates blocked with phenol derivatives, oximes, caprolactams, etc.; and combinations of two or more of these. Epichlorohydrin is a typical example of an epoxidizing agent.

[0080] The ratio of the isocyanating agent is typically 5 / 1 to 1 / 1, preferably 4 / 1 to 1.2 / 1, and more preferably 2.5 / 1 to 1.5 / 1, based on the equivalent ratio [NCO] / [OH] of isocyanate groups [NCO] to the hydroxyl groups [OH] of the base polyester. If [NCO] / [OH] exceeds 5, the low-temperature fixability deteriorates. If the molar ratio of [NCO] is less than 1, the urea content of this polyester prepolymer becomes low, and the resistance to hot offset deteriorates. The isocyanate content in this polyester prepolymer is typically 0.5 to 40% by weight, preferably 1 to 30% by weight, and more preferably 2 to 20% by weight. Below 0.5% by weight, the hot offset resistance deteriorates, and it becomes disadvantageous in terms of achieving both heat resistance and low-temperature fixation. Above 40% by weight, low-temperature fixation deteriorates.

[0081] Furthermore, the number of isocyanate groups contained per molecule in this polyester prepolymer is usually one or more, preferably an average of 1.5 to 3, and more preferably an average of 1.8 to 2.5. If there is less than one group per molecule, the molecular weight of the urea-modified polyester resin after the extension reaction becomes low, and the hot offset resistance deteriorates.

[0082] The binder resin precursor has a weight-average molecular weight of 1 × 10⁻⁶ 4 The above 3 x 10 5 The following is preferable:

[0083] (A compound that extends or crosslinks with a binder resin precursor) The binder resin preferably contains a compound that elongates or crosslinks with the binder resin precursor.

[0084] Compounds that extend or crosslink with the binder resin precursor include compounds having active hydrogen groups (active hydrogen group-containing compounds), and representative examples include amines. Examples of amines include diamine compounds, polyamine compounds with a valency of 3 or higher, amino alcohol compounds, amino mercaptan compounds, amino acid compounds, and compounds in which these amino groups are blocked. Examples of diamine compounds include aromatic diamines (phenylenediamine, diethyltoluenediamine, 4,4'-diaminodiphenylmethane, etc.); alicyclic diamines (4,4'-diamino-3,3'dimethyldicyclohexylmethane, diaminecyclohexane, isophoronediamine, etc.); and aliphatic diamines (ethylenediamine, tetramethylenediamine, hexamethylenediamine, etc.). Examples of polyamine compounds with a valency of 3 or higher include diethylenetriamine and triethylenetetramine. Examples of amino alcohol compounds include ethanolamine and hydroxyethylaniline. Examples of amino mercaptan compounds include aminoethyl mercaptan and aminopropyl mercaptan.

[0085] Examples of amino acid compounds include aminopropionic acid and aminocaproic acid. Examples of compounds in which the amino group of these compounds is blocked include ketimine compounds and oxazoline compounds obtained from amines and ketones (acetone, methyl ethyl ketone, methyl isobutyl ketone, etc.). Among these amines, diamine compounds and mixtures of diamine compounds with a small amount of polyamine compounds are preferred.

[0086] <Other ingredients> Other components are not particularly limited and can be selected as appropriate depending on the purpose. Examples include colorants, release agents, charge control agents, external additives, fluidity improvers, cleaning properties improvers, and magnetic materials.

[0087] (Coloring agent) All known dyes and pigments can be used as colorants, for example, carbon black, nigrosine dye, iron black, naphthol yellow S, Hansa yellow (10G, 5G, G), cadmium yellow, yellow iron oxide, ochre, yellow lead, titanium yellow, polyazo yellow, oil yellow, Hansa yellow (GR, A, RN, R), pigment yellow L, benzidine yellow (G, GR), permanent yellow (NCG), Balkanfast yellow (5G, R), tartrazine lake, quinoline yellow lake, anthrazan yellow BGL, isoindolinone yellow Lowe, Bengara, Red Lead, Red Lead, Cadmium Red, Cadmium Mercury Red, Antimony Red, Permanent Red 4R, Para Red, Faise Red, Parachlor-Orthonitroaniline Red, Risol Fast Scarlet G, Brilliant Fast Scarlet, Brilliant Carmine BS, Permanent Red (F2R, F4R, FRL, FRLL, F4RH), Fast Scarlet VD, Belkan Fast Rubin B, Brilliant Scarlet G, Risol Rubin GX, Permanent Red F5R, Brilliant Carmine 6B, Pogme Bon Maroon 3B, Bordeaux 5B, Toluidine Maroon, Permanent Bordeaux F2K, Helio Bordeaux BL, Bordeaux 10B, Bon Maroon Light, Bon Maroon Medium, Eosin Lake, Rhodamine Lake B, Rhodamine Lake Y, Alizarin Lake, Thioindigo Red B, Thioindigo Maroon, Oil Red, Quinacridone Red, Pyrazolone Red, Polyazo Red, Chrome Vermilion, Benzidine Orange, Perinon Orange, Oil Orange, Cobalt Blue, Cerulean Blue, Alkali Blue Lake, Peacock Blue Lake, Victoria Blue Lake, Metal-free Phthalocyanine Blue, Phthalocyanine Blue, Fast Sky Blue, Indanthrene Blue (RS, BC), Indigo, Ultramarine, Prussian Blue, Anthraquinone Blue, Fast Violet B, Methyl Violet Lake, Cobalt Purple, Manganese Purple, Dioxane Violet, Anthraquinone Violet, Chrome Green, Zinc Green, Chromium Oxide, Pyridian, Emerald Green, Pigment Green B, Naphthol Green B, Green Gold, Acid Green Lake, Malachite Green Lake,Phthalocyanine green, anthraquinone green, titanium dioxide, zinc oxide, lithobone, and mixtures thereof can be used. The colorant content is usually 1 to 15% by weight, preferably 3 to 10% by weight, relative to the toner.

[0088] The colorant can also be used as a masterbatch compounded with the resin. In addition to the modified and unmodified polyester resins mentioned above, the binder resins used in the production of the masterbatch include polymers of styrene and its substituted derivatives such as polystyrene, poly-p-chlorostyrene, and polyvinyltoluene; styrene-p-chlorostyrene copolymer, styrene-propylene copolymer, styrene-vinyltoluene copolymer, styrene-vinylnaphthalene copolymer, styrene-methyl acrylate copolymer, styrene-ethyl acrylate copolymer, styrene-butyl acrylate copolymer, styrene-octyl acrylate copolymer, styrene-methyl methacrylate copolymer, styrene-ethyl methacrylate copolymer, styrene-butyl methacrylate copolymer, styrene-α-chloromethacrylate copolymer, and Examples include styrene copolymers such as ethylene-acrylonitrile copolymer, styrene-vinyl methyl ketone copolymer, styrene-butadiene copolymer, styrene-isoprene copolymer, styrene-acrylonitrile-indene copolymer, styrene-maleic acid copolymer, and styrene-maleic acid ester copolymer; polymethyl methacrylate, polybutyl methacrylate, polyvinyl chloride, polyvinyl acetate, polyethylene, polypropylene, polyester, epoxy resin, epoxy polyol resin, polyurethane, polyamide, polyvinyl butyral, polyacrylic acid resin, rosin, modified rosin, terpene resin, aliphatic or alicyclic hydrocarbon resin, aromatic petroleum resin, chlorinated paraffin, and paraffin wax, which can be used individually or in combination.

[0089] A masterbatch can be obtained by mixing and kneading a masterbatch resin and a colorant under high shear force. In this process, an organic solvent can be used to enhance the interaction between the colorant and the resin. Another preferred method is the so-called flushing method, in which an aqueous paste containing water from the colorant is mixed and kneaded with the resin and organic solvent to transfer the colorant to the resin side and remove the water and organic solvent components. This method allows the wet cake of the colorant to be used as is, eliminating the need for drying. A high-shear dispersion device such as a three-roll mill is preferably used for mixing and kneading.

[0090] (Release agent) The release agent is preferably a wax with a melting point of 50 to 120°C. Such a wax can effectively act as a release agent between the fixing roller and the toner interface, thereby improving high-temperature offset resistance without the need to apply a release agent such as oil to the fixing roller.

[0091] The melting point of the wax is determined by measuring the maximum endothermic peak using a differential scanning calorimeter, the TG-DSC system TAS-100 (manufactured by Rigaku Denki Co., Ltd.).

[0092] The following materials can be used as release agents. Examples of waxes and waxes include plant-based waxes such as carnauba wax, cotton wax, wood wax, and rice wax; animal-based waxes such as beeswax and lanolin; mineral-based waxes such as ozokerite and cerucine; and petroleum waxes such as paraffin, microcrystalline, and petrolatum. Other release agents besides these natural waxes include synthetic hydrocarbon waxes such as Fischer-Tropsch wax and polyethylene wax; and synthetic waxes such as esters, ketones, and ethers. Furthermore, fatty acid amides such as 1,2-hydroxystearamide, stearamide, phthalimide anhydride, and chlorinated hydrocarbons; and crystalline polymers having long-chain alkyl groups in their side chains, such as low molecular weight crystalline polymers like polyacrylate homopolymers or copolymers of polyacrylates such as polystearyl methacrylate and polynauryl methacrylate (e.g., n-stearyl methacrylate copolymer), can also be used as release agents.

[0093] (Static control agent) A toner according to one embodiment may contain a charge control agent as needed. Any known charge control agent can be used, such as nigrosine dyes, triphenylmethane dyes, chromium-containing metal complex dyes, molybdate chelate pigments, rhodamine dyes, alkoxyamines, quaternary ammonium salts (including fluorine-modified quaternary ammonium salts), alkylamides, elemental or compound phosphorus, elemental or compound tungsten, fluorine-based surfactants, metal salicylic acid salts, and metal salts of salicylic acid derivatives.

[0094] Specifically, these include Bontron 03 (a nigrosine-based dye), Bontron P-51 (a quaternary ammonium salt), Bontron S-34 (a metal-containing azo dye), E-82 (an oxynaphthoic acid-based metal complex), E-84 (a salicylic acid-based metal complex), and E-89 (a phenolic condensate) (all manufactured by Orient Chemical Industry Co., Ltd.), TP-302 and TP-415 (quaternary ammonium salt molybdenum complexes) (both manufactured by Hodogaya Chemical Co., Ltd.), Copy Charge PSY VP2038 (a quaternary ammonium salt), Copy Blue PR (a triphenylmethane derivative), Copy Charge NEG VP2036 (a quaternary ammonium salt), and Copy Charge NX Examples include VP434 (manufactured by Hoechst), LRA-901, the boron complex LR-147 (manufactured by Nippon Carlit Co., Ltd.), copper phthalocyanine, perylene, quinacridone, azo pigments, and other polymer compounds having functional groups such as sulfonic acid groups, carboxyl groups, and quaternary ammonium salts.

[0095] The amount of charge control agent used is determined by the type of binder resin, the presence or absence of additives used as needed, and the toner manufacturing method including the dispersion method, and is not uniquely limited, but preferably it is used in the range of 0.1 to 10 parts by mass per 100 parts by mass of binder resin. Preferably, it is in the range of 0.2 to 5 parts by mass. If it exceeds 10 parts by mass, the charge of the toner will be too high, reducing the effect of the main charge control agent, increasing the electrostatic attraction force with the developing roller, leading to a decrease in the fluidity of the developer and a decrease in image density. These charge control agents can be dissolved and dispersed after melting and kneading with the masterbatch and resin, or they can be added when directly dissolving and dispersing in an organic solvent, or they can be fixed to the toner surface after toner particle formation.

[0096] (External additive) A toner according to one embodiment may contain an external additive to enhance fluidity, developability, and electrostatic properties. Other inorganic microparticles and polymer microparticles besides the inorganic fillers mentioned above can be used as external additives.

[0097] Examples of inorganic fine particles include silica, alumina, titanium oxide, barium titanate, magnesium titanate, calcium titanate, strontium titanate, iron oxide, copper oxide, zinc oxide, tin oxide, silica sand, clay, mica, wollastonite, diatomaceous earth, chromium oxide, cerium oxide, red iron oxide, antimony trioxide, magnesium oxide, zirconium oxide, barium sulfate, barium carbonate, calcium carbonate, silicon carbide, and silicon nitride. Among these, silica, alumina, and titanium oxide are preferred.

[0098] Furthermore, the inorganic fine particles may be surface-treated with a hydrophobic treatment agent to enhance their hydrophobicity and suppress deterioration of flow and charge properties even under high humidity conditions. Preferred hydrophobic treatment agents include, for example, silane coupling agents, silylation agents, silane coupling agents having alkyl fluoride compounds, organic titanate coupling agents, aluminum coupling agents, silicone oil, and modified silicone oil.

[0099] Examples of polymer-based fine particles include polymer particles made from polystyrene, methacrylic acid esters, acrylic acid ester copolymers, polycondensation systems such as silicon, benzoguanamine, and nylon, and thermosetting resins, obtained by soap-free emulsion polymerization, suspension polymerization, or dispersion polymerization.

[0100] Furthermore, there are no particular restrictions on the average particle size of the primary inorganic fine particles, and it can be appropriately selected depending on the purpose, but it is preferably 5 nm to 2 μm, and more preferably 10 nm to 500 nm. If the average particle size is 5 nm or more, aggregation of inorganic fine particles is suppressed, and the inorganic fine particles can be uniformly dispersed in the resin particles. If the average particle size is 2 μm or less, improved heat resistance and storage properties can be obtained due to the filler effect.

[0101] The average particle diameter is a value directly determined from photographs obtained by a transmission electron microscope, and it is preferable to observe at least 100 particles and use the average value of their major axes.

[0102] The specific surface area of ​​inorganic nanoparticles calculated by the BET method is 20-500 m². 2 It is preferable that it be / g.

[0103] The inorganic fine particle content is preferably 0.01% to 5% by mass of the resin particles.

[0104] (Cleaning performance enhancer) The cleaning agent is not particularly limited as long as it is added to the resin particles to remove residual developer after transfer from the photoreceptor or primary transfer medium, and can be appropriately selected according to the purpose. Examples of cleaning agents include fatty acid metal salts such as zinc stearate, calcium stearate, and stearic acid, polymer fine particles produced by soap-free emulsion polymerization such as polymethyl methacrylate fine particles and polystyrene fine particles. The polymer fine particles are preferably those with a relatively narrow particle size distribution, and those with a volume average particle size of 0.01 μm to 1 μm are preferred.

[0105] (Magnetic material) There are no particular restrictions on the magnetic material; it can be appropriately selected from known materials depending on the purpose, such as iron powder, magnetite, and ferrite. Among these, white materials are preferred in terms of color.

[0106] <Toner manufacturing method> One embodiment of the toner manufacturing method involves dispersing an oil phase containing a crystalline polyester resin, an amorphous polyester resin, and an inorganic filler that has not been resin-masterbatched as a binder resin component in an organic solvent by shear force or impact force, then dispersing it in an aqueous medium, and removing the organic solvent from the resulting dispersion to obtain toner.

[0107] Furthermore, as a method for producing toner according to one embodiment, it is preferable to dissolve a binder resin precursor consisting of a colorant, a mold release agent, an inorganic filler, a crystalline polyester dispersion, and a modified polyester resin, as well as other binder resin components, in an oil phase obtained by dissolving these in an organic solvent, then disperse the oil phase in an aqueous medium containing a fine particle dispersant to obtain an emulsified dispersion, and carry out a crosslinking reaction and / or extension reaction of the binder resin precursor in the emulsified dispersion, thereby removing the organic solvent.

[0108] It is preferable that the crystalline polyester resin is dispersed by a dispersion step before being added to the organic solvent that forms the oil phase, and that the crystalline polyester dispersion obtained in the dispersion step can be added directly to the oil phase.

[0109] The method of dispersing the oil phase is not particularly limited, but for fine dispersion by shear, a preferred method is to pulverize the material with a high shear force generated in the narrow gap between the rotor and stator. For fine dispersion by impact, a preferred method is to fill the vessel with beads such as zirconia and rotate it, thereby pulverizing the material through collisions between the beads or between the beads and the vessel.

[0110] Impact pulverization is particularly effective for large materials exceeding 1 μm, while shear pulverization is effective for further refining submicron-order materials. Since the two methods primarily target different pulverization regions, combining them can improve material uniformity; therefore, combining the two methods is particularly preferable. There is no limitation on the order of dispersion by shear and dispersion by impact.

[0111] To efficiently miniaturize the material, it is preferable for the rotor peripheral speed to exceed 12 m / s for fine dispersion by shearing. For crushing by impact, it is preferable to set the disc peripheral speed to 6 m / s or higher, and even more preferable to 10 m / s to 12 m / s. In crushing by impact, if the disc peripheral speed is less than 6 m / s, sufficient crushing energy cannot be obtained, and uneven distribution of beads occurs, resulting in insufficient dispersion. Conversely, if the disc peripheral speed is too high, excessive dispersion occurs, raising concerns about reduced cleaning performance due to a decrease in background toner. There are also risks such as increased liquid temperature and re-aggregation due to over-dispersion.

[0112] The media diameter is preferably 0.5 mm or less, and more preferably 0.3 mm or less. The smaller the beads, the greater the total surface area of ​​the beads, which increases the opportunities for dispersion by collision and improves dispersion efficiency. If the beads are too small, the mesh size of the screen separating the beads from the process liquid must also be narrowed, which can lead to insufficient flow rate, causing the liquid temperature to rise and increasing the risk of re-aggregation.

[0113] When dispersing materials in an oil phase using a media-type disperser by impact force, if the oil phase contains inorganic fillers, the material can be dispersed more efficiently than when inorganic fillers are not included. This reduces the amount of toner particles with non-uniform composition and further narrows the particle size distribution of the toner. This is because collision opportunities occur not only between beads and between beads and vessels, but also between beads and inorganic fillers, and between vessels and inorganic fillers, allowing for the effective dispersion of low-hardness organic materials.

[0114] In rotor-stator type shear dispersion, adding inorganic fillers does not improve grinding efficiency; therefore, it is important to utilize inorganic fillers as a grinding medium.

[0115] (organic solvent) The organic solvent used in the crystalline polyester dispersion process is one that completely dissolves the crystalline polyester resin at high temperatures to form a homogeneous solution, but conversely, separates from the crystalline polyester resin when cooled to low temperatures, forming an opaque, heterogeneous solution. Specifically, any solvent that exhibits non-solvent properties at temperatures below (Tm-40)°C (based on the melting temperature (Tm) of the crystalline polyester resin) and good solvent properties at temperatures above that is acceptable. Specific examples include toluene, ethyl acetate, butyl acetate, methyl ethyl ketone, and methyl isobutyl ketone, which can be used individually or in combination of two or more.

[0116] (Heating and melting / cooling of crystalline polyester resin) Crystalline polyester resin dissolves when heated to high temperatures in an organic solvent and recrystallizes when cooled. However, this process is carried out using only the crystalline polyester resin. If amorphous polyester resin is mixed in during this process, the crystalline and amorphous polyesters will become miscible during heating and dissolution, preventing the sharp melt properties of the crystalline polyester from being utilized in the toner. Therefore, the heating, dissolution, and cooling process must be carried out using only the crystalline polyester in an organic solvent. Furthermore, the dispersion particle size of the crystalline polyester resin precipitated during the cooling process is determined by the concentration of the solution and the cooling rate.

[0117] (Dissolution and pulverization of amorphous polyester resin) Furthermore, amorphous polyester resin is dissolved in the cooled dispersion and then micronized using a mechanical grinding device to produce a crystalline polyester dispersion. When crystalline polyester resin is dispersed alone in an organic solvent, the solution viscosity increases as the dispersion particle size decreases, making it difficult to supply the solution to the mechanical grinding device. While it is possible to lower the solution concentration to reduce the viscosity, this is not practical. Therefore, amorphous polyester is dissolved in the cooled dispersion to control the solution viscosity and enable mechanical grinding.

[0118] Furthermore, when considering the dispersed particle size in mechanical grinding, if it exceeds 1.0 μm, granulation of the toner becomes difficult, and the particle size distribution tends to become broad; therefore, a dispersed particle size of 1.0 μm or less is preferable.

[0119] Regarding the solution concentration, during high-temperature dissolution / cooling, it is preferable to use 1 to 20% by weight of crystalline polyester resin in the organic solvent. During mechanical grinding, it is desirable to mix in amorphous polyester so that the ratio of crystalline polyester resin to amorphous polyester resin is 10 / 90 to 90 / 10.

[0120] (Mechanical grinding device) Commercially available grinding equipment can be used in the process of micronizing the crystalline polyester resin precipitated during the cooling process. Examples include bead mills, ball mills, and wet-type fine grinding equipment (such as the Ultimizer equipment manufactured by Sugino Machine).

[0121] (Toner manufacturing method in aqueous media) The binder resin precursor, colorant, release agent, inorganic filler, crystalline polyester dispersion, charge control agent, and unmodified polyester resin that form toner particles may be mixed when forming the dispersion in an aqueous medium, but it is more preferable to mix these toner raw materials beforehand and then add the mixture to the aqueous medium for dispersion. Furthermore, other toner raw materials such as colorants, release agents, and charge control agents do not necessarily need to be mixed when forming particles in the aqueous medium, and may be added after the toner particles have been formed. For example, after forming toner particles without a colorant, a colorant can be added using a known dyeing method.

[0122] As an aqueous medium, water alone may be used, but a miscible solvent can also be used in combination with water. Examples of miscible solvents include alcohols (methanol, isopropanol, ethylene glycol, etc.), dimethylformamide, tetrahydrofuran, cellosolves (methyl cellosolve, etc.), and lower ketones (acetone, methyl ethyl ketone, etc.).

[0123] While there are no particular limitations on the dispersion method, known equipment such as low-speed shear, high-speed shear, friction, high-pressure jet, and ultrasonic dispersion can be applied. High-speed shear dispersion is preferred to achieve a dispersion particle size of 2 to 20 μm. When using a high-speed shear disperser, there are no particular limitations on the rotation speed, but it is usually 1,000 to 30,000 rpm, preferably 5,000 to 20,000 rpm. There are no particular limitations on the dispersion time, but in the case of a batch system, it is usually 0.1 to 60 minutes. The dispersion temperature is usually 0 to 80°C (under pressure), preferably 10 to 40°C.

[0124] The amount of aqueous medium used per 100 parts by mass of toner composition is typically 100 to 1000 parts by mass. Using less than 100 parts by mass results in poor dispersion of the toner composition, making it impossible to obtain toner particles of the desired size. Using more than 1000 parts by mass is not economical. Dispersants can also be used as needed. Using a dispersant is preferable because it results in a sharper particle size distribution and more stable dispersion.

[0125] As a method for reacting a polyester prepolymer with a compound having active hydrogen groups, the compound having active hydrogen groups may be added and reacted before dispersing the toner composition in an aqueous medium, or the compound having active hydrogen groups may be added after dispersion in an aqueous medium to initiate the reaction from the particle interface. In this case, modified polyester due to the polyester prepolymer is preferentially formed on the surface of the manufactured toner, and a concentration gradient can be created within the particles.

[0126] Examples of dispersants for emulsifying and dispersing the oil phase in which the toner composition is dispersed in a liquid containing water include anionic surfactants such as alkylbenzene sulfonates, α-olefin sulfonates, and phosphate esters; amine salts such as alkylamine salts, amino alcohol fatty acid derivatives, polyamine fatty acid derivatives, and imidazolines; quaternary ammonium salts such as alkyltrimethylammonium salts, dialkyldimethylammonium salts, alkyldimethylbenzylammonium salts, pyridinium salts, alkylisoquinolinium salts, and benzethonium chloride; nonionic surfactants such as fatty acid amide derivatives and polyhydric alcohol derivatives; and amphoteric surfactants such as alanine, dodecyldi(aminoethyl)glycine, di(octylaminoethyl)glycine, and N-alkyl-N,N-dimethylammonium betaine.

[0127] Furthermore, by using surfactants containing fluoroalkyl groups, the effect can be achieved with very small amounts. Preferably used anionic surfactants containing fluoroalkyl groups include fluoroalkyl carboxylic acids having 2 to 10 carbon atoms and their metal salts, disodium perfluorooctanesulfonyl glutamate, sodium 3-[omega-fluoroalkyl(C6~C11)oxy]-1-alkyl(C3~C4) sulfonate, sodium 3-[omega-fluoroalkanoyl(C6~C8)-N-ethylamino]-1-propanesulfonate, fluoroalkyl(C11~C20) carboxylic acids and their metal salts, and perfluoro Examples include alkyl carboxylic acids (C7-C13) and their metal salts, perfluoroalkyl (C4-C12) sulfonic acids and their metal salts, perfluorooctanesulfonic acid diethanolamide, N-propyl-N-(2-hydroxyethyl) perfluorooctanesulfonamide, perfluoroalkyl (C6-C10) sulfonamidopropyltrimethylammonium salt, perfluoroalkyl (C6-C10)-N-ethylsulfonylglycine salt, and monoperfluoroalkyl (C6-C16) ethyl phosphate esters.

[0128] Examples of product names include Surflon S-111, S-112, S-113 (manufactured by Asahi Glass Co.), Florard FC-93, FC-95, FC-98, FC-L29 (manufactured by Sumitomo 3M), Unidyne DS-101, DS-L02 (manufactured by Daikin Industries), Megafac F-LL0, F-L20, F-113, F-191, F-812, F-833 (manufactured by Dainippon Ink Co.), Extop EF-102, L03, 104, 105, 112, 123A, 123B, 306A, 501, 201, 204 (manufactured by Tochem Products), and Futergent F-100, F150 (manufactured by Neos Co.).

[0129] Furthermore, examples of cationic surfactants include aliphatic primary, secondary, or tertiary amine acids having fluoroalkyl groups, aliphatic quaternary ammonium salts such as perfluoroalkyl (C6-C10) sulfonamidopropyltrimethylammonium salt, benzalkonium salts, benzethonium chloride, pyridinium salts, imidazolinium salts, and trade names such as Surflon S-L21 (manufactured by Asahi Glass Co., Ltd.), Florard FC-135 (manufactured by Sumitomo 3M Corporation), Unidyne DS-202 (manufactured by Daikin Industries, Ltd.), Megafac F-150, F-824 (manufactured by Dainippon Ink & Chemicals Inc.), Extop EF-L32 (manufactured by Tochem Products Inc.), and Futergent F-300 (manufactured by Neos Inc.).

[0130] In addition, tricalcium phosphate, calcium carbonate, titanium dioxide, colloidal silica, hydroxyapatite, and the like can be used as dispersants of inorganic compounds that are poorly soluble in water.

[0131] The dispersion droplets may also be stabilized with polymeric protective colloids or water-insoluble organic fine particles. For example, acids such as acrylic acid, methacrylic acid, α-cyanoacrylic acid, α-cyanomethacrylic acid, itaconic acid, crotonic acid, fumaric acid, maleic acid, or maleic anhydride; or (meth)acrylic monomers containing hydroxyl groups, such as β-hydroxyethyl acrylate, β-hydroxyethyl methacrylate, β-hydroxypropyl acrylate, β-hydroxypropyl methacrylate, γ-hydroxypropyl acrylate, γ-hydroxypropyl methacrylate, 3-chloro-2-hydroxypropyl acrylate, 3-chloro-2-hydroxypropyl methacrylate, diethylene glycol monoacrylate, diethylene glycol monomethacrylate, glycerin monoacrylate, glycerin monomethacrylate, N-methylolacrylamide, N-methylolmethacrylamide, etc.; vinyl alcohol or ethers with vinyl alcohol, such as vinyl methyl ether, vinyl ethyl ether, vinyl propyl ether, etc.; or vinyl alcohol Esters of compounds containing carboxyl groups, such as vinyl acetate, vinyl propionate, vinyl butyrate, etc.; acrylamide, methacrylamide, diacetone acrylamide or their methylol compounds; acid chlorides such as acrylate chloride and methacrylic acid chloride; homopolymers or copolymers having nitrogen atoms or heterocycles such as vinylpyridine, vinylpyrrolidone, vinylimidazole, and ethyleneimine; polyoxyethylene-based compounds such as polyoxyethylene, polyoxypropylene, polyoxyethylene alkylamine, polyoxypropylene alkylamine, polyoxyethylene alkylamide, polyoxyethylene nonylphenyl ether, polyoxyethylene laurylphenyl ether, polyoxyethylene stearylphenyl ester, and polyoxyethylene nonylphenyl ester; and celluloses such as methylcellulose, hydroxyethylcellulose, and hydroxypropylcellulose.

[0132] If a dispersion stabilizer such as calcium phosphate is used, the calcium phosphate should be removed from the fine particles by dissolving it with an acid such as hydrochloric acid and then washing with water. It can also be removed by other methods such as enzymatic decomposition.

[0133] When a dispersant is used, it is possible to leave the dispersant on the surface of the toner particles, but it is preferable to wash it off after the reaction to prevent the toner from becoming charged.

[0134] Furthermore, to lower the viscosity of the toner composition, a solvent in which the polyester prepolymer reacts and modifies the polyester can be soluble can be used. Using a solvent is preferable because it results in a sharper particle size distribution.

[0135] The solvent is preferably volatile with a boiling point below 100°C because it is easy to remove. Examples of solvents include toluene, xylene, benzene, carbon tetrachloride, methylene chloride, 1,2-dichloroethane, 1,1,2-trichloroethane, trichloroethylene, chloroform, monochlorobenzene, dichloroethylidene, methyl acetate, ethyl acetate, methyl ethyl ketone, and methyl isobutyl ketone, which can be used individually or in combination of two or more. Aromatic solvents such as toluene and xylene, and halogenated hydrocarbons such as methylene chloride, 1,2-dichloroethane, chloroform, and carbon tetrachloride are particularly preferred.

[0136] The amount of solvent used per 100 parts by mass of polyester prepolymer is usually 0 to 300 parts by mass, preferably 0 to 100 parts by mass, and more preferably 25 to 70 parts by mass.

[0137] If a solvent is used, remove it by heating under atmospheric pressure or reduced pressure after the extension and / or crosslinking reaction.

[0138] The elongation and / or crosslinking reaction time is selected based on the reactivity of the combination of the polyester prepolymer and the compound having active hydrogen groups, but is usually 10 minutes to 40 hours, preferably 30 minutes to 24 hours. The reaction temperature is usually 0°C to 100°C, preferably 10°C to 50°C.

[0139] Furthermore, known catalysts can be used as needed. Specifically, examples include tertiary amines such as triethylamine and imidazoles.

[0140] There are no particular restrictions on how to remove the organic solvent from the resulting emulsion dispersion; known methods can be used. For example, a method can be employed in which the entire system is gradually heated while stirring under atmospheric or reduced pressure, and the organic solvent in the droplets is completely evaporated and removed.

[0141] Known techniques are used for washing and drying toner matrix particles dispersed in an aqueous medium. Specifically, after solid-liquid separation using a centrifuge, filter press, etc., the obtained toner cake is redispersed in deionized water at room temperature to about 40°C, the pH is adjusted with acid or alkali as needed, and then solid-liquid separation is repeated several times to remove impurities and surfactants, etc. Then, toner powder is obtained by drying using an airflow dryer, circulating dryer, vacuum dryer, vibrating fluidized bed dryer, etc. At this time, fine particle components of the toner may be removed by centrifugation, etc., and after drying, a known classifier can be used as needed to obtain the desired particle size distribution. However, according to the toner according to one embodiment, toner matrix particles with the desired particle size distribution can be produced without the need for classification, thus avoiding yield reduction due to classification.

[0142] For mixing external additives used to enhance fluidity, developability, and electrostatic properties, a general powder mixer is used, but it is preferable to equip it with a jacket or similar device to regulate the internal temperature. To change the history of the load applied to the external additive, the additive can be added either midway or gradually. In this case, the rotation speed, rolling speed, time, and temperature of the mixer may be changed. Alternatively, a strong load may be applied first, followed by a relatively weak load, or vice versa.

[0143] Suitable mixing equipment includes, for example, V-type mixers, rocking mixers, Lödige mixers, Nauter mixers, and Henschel mixers. The mixture is then passed through a sieve of 250 mesh or larger to remove coarse particles and aggregated particles, yielding toner.

[0144] Thus, the toner according to one embodiment contains a binder resin, an inorganic filler, and a crystalline polyester resin. The toner according to one embodiment is observed to have a particle cross-section of the toner, and the inorganic filler is composed of A l When mapping the constituent elements including Si, Fe, Ca, Mg, and Ti, the proportion of particles containing domains with a maximum diameter of 2.0 μm or more in any of the constituent elements of the inorganic filler is set to 10% or less of the total number of observed toner particles. Furthermore, the toner according to one embodiment has a volume-average particle size of 6.0 μm or less, and a value of (volume-average particle size / number-average particle size) of 1.15 or less. Because the toner according to one embodiment can have a sharp particle size distribution, it can have a good manufacturing yield and excellent transferability, resistance to in-machine contamination, heat resistance, and low-temperature fixing properties.

[0145] In one embodiment, the toner can have a (volume-average particle size / number-average particle size) value of 1.10 to 1.13. As a result, the toner according to one embodiment can have a sharper particle size distribution, thereby improving manufacturing yield, transferability, resistance to in-machine contamination, heat resistance, and low-temperature fixation.

[0146] In one embodiment, the toner can have a volume-average particle size of 4.0 μm to 5.5 μm. As a result, the toner in one embodiment can suppress fluctuations in particle size and have a sharper particle size distribution, which makes it easier to further increase the manufacturing yield and further improves transferability, resistance to in-machine contamination, heat resistance, and low-temperature fixation.

[0147] In one embodiment, the toner can have an acid value of 10 mg KOH / g to 30 mg KOH / g. This allows the toner to be granulated with a sharp particle size distribution during the granulation process in toner production, further improving the manufacturing yield and providing a toner with excellent transferability, resistance to in-machine contamination, heat resistance, and low-temperature fixation.

[0148] <Developer> A developer according to one embodiment includes a toner according to one embodiment and may optionally contain other components such as a carrier, as appropriate. This allows for excellent transferability, electrostatic properties, etc., and enables the stable formation of high-quality images.

[0149] The developer may be a one-component developer or a two-component developer, but when used in high-speed printers and the like to accommodate the recent increase in information processing speed, a two-component developer is preferable from the standpoint of extending its lifespan.

[0150] When toner according to one embodiment is used in a one-component developer, even when toner is replenished, fluctuations in toner particle size are small, toner filming onto the developing roller and toner fusion onto components such as blades that thin the toner layer are minimized, and good and stable developability and high image quality can be obtained even when agitated for a long period of time in the developing device.

[0151] When using a toner according to one embodiment as a one-component developer, the one-component developer may be a one-component developer without a carrier, i.e., a magnetic toner or a non-magnetic toner.

[0152] When the developer according to one embodiment is used as a two-component developer, it can be used as a developer after being mixed with a carrier. When the toner according to one embodiment is used as a two-component developer, even if the toner is balanced over a long period of time, there is little change in the toner particle size, and good and stable developability and images can be obtained even if the toner is agitated for a long period of time in the developing device.

[0153] The toner content in the two-component developer can be appropriately selected depending on the purpose, but is preferably 2 to 10 parts by mass per 100 parts by mass of the two-component developer. The carrier content in the two-component developer can be appropriately selected depending on the purpose, but is preferably 90 to 98 parts by mass, and more preferably 93 to 97 parts by mass per 100 parts by mass of the two-component developer.

[0154] The developer according to one embodiment can be suitably used for image formation by various known electrophotographic methods, such as magnetic one-component development methods, non-magnetic one-component development methods, and two-component development methods.

[0155] [Career] The carrier is not particularly limited and can be appropriately selected according to the purpose, but it is preferable that it has a core material and a resin layer (coating layer) that covers the core material.

[0156] (Core material) There are no particular restrictions on the core material, and it can be appropriately selected according to the purpose. Examples include manganese-strontium materials with a magnetization of 50 emu / g to 90 emu / g, and manganese-magnesium materials with a magnetization of 50 emu / g to 90 emu / g. In order to ensure image density, it is preferable to use highly magnetized materials such as iron powder of 100 emu / g or more, or magnetite with a magnetization of 75 emu / g to 120 emu / g. Furthermore, it is preferable to use low magnetized materials such as copper-zinc materials with a magnetization of 30 emu / g to 80 emu / g, as this can mitigate the impact of the developer in a slushy state on the photoreceptor and is advantageous for improving image quality. These may be used individually or in combination of two or more types.

[0157] The volume-average particle size of the core material is not particularly limited and can be appropriately selected depending on the purpose, but 10 μm to 150 μm is preferred, and 40 μm to 100 μm is more preferred. If the volume-average particle size is 10 μm or more, the problem of a large amount of fine powder in the carrier, which can reduce the magnetization per particle and cause carrier scattering can be effectively prevented. On the other hand, if it is 150 μm or less, the specific surface area decreases, which can cause toner scattering, and in full-color printing with many solid areas, this can effectively prevent the problem of poor reproduction of solid areas in particular.

[0158] (Resin layer) There are no particular restrictions on the material of the resin layer, and it can be appropriately selected from known resins according to the purpose. Examples include amino resins, polyvinyl resins, polystyrene resins, polyhalogenated olefins, polyester resins, polycarbonate resins, polyethylene, polyvinyl fluoride, polyvinylidene fluoride, polytrifluoroethylene, polyhexafluoropropylene, copolymers of vinylidene fluoride and acrylic monomers, copolymers of vinylidene fluoride and vinyl fluoride, fluoropolymers such as copolymers of tetrafluoroethylene, vinylidene fluoride and monomers without fluoro groups, and silicone resins. These may be used individually or in combination of two or more.

[0159] There are no particular restrictions on amino-based resins, and they can be appropriately selected depending on the purpose. Examples include urea-formaldehyde resin, melamine resin, benzoguanamine resin, urea resin, polyamide resin, epoxy resin, and the like.

[0160] There are no particular restrictions on the polyvinyl resin used, and it can be appropriately selected depending on the purpose. Examples include acrylic resin, polymethyl methacrylate, polyacrylonitrile, polyvinyl acetate, polyvinyl alcohol, and polyvinyl butyral.

[0161] There are no particular restrictions on the polystyrene-based resin, and it can be appropriately selected depending on the purpose. Examples include polystyrene and styrene-acrylic copolymers.

[0162] There are no particular restrictions on the polyhalogenated olefin, and it can be appropriately selected depending on the purpose. Examples include polyvinyl chloride, etc.

[0163] There are no particular restrictions on the polyester resin used; it can be appropriately selected depending on the purpose. Examples include polyethylene terephthalate and polybutylene terephthalate.

[0164] The resin layer may contain conductive powder or the like, if necessary. There are no particular restrictions on the conductive powder, and it can be appropriately selected depending on the purpose. Examples include metal powder, carbon black, titanium dioxide, tin oxide, zinc oxide, etc. The average particle size of the conductive powder is preferably 1 μm or less. When the average particle size is 1 μm or less, the electrical resistance can be controlled.

[0165] The resin layer can be formed by dissolving a silicone resin or the like in a solvent to prepare a coating solution, then applying the coating solution to the surface of the core material using a known coating method, drying it, and then baking it.

[0166] There are no particular restrictions on the application method, and it can be appropriately selected according to the purpose. For example, immersion coating, spray coating, brush coating, etc., can be used.

[0167] There are no particular restrictions on the solvent, and it can be appropriately selected depending on the purpose. Examples include toluene, xylene, methyl ethyl ketone, methyl isobutyl ketone, butyl cellosolve acetate, and the like.

[0168] The baking process may be carried out using an external heating method or an internal heating method, such as using a fixed electric furnace, a fluidized bed electric furnace, a rotary electric furnace, a burner furnace, or a microwave.

[0169] There are no particular restrictions on the resin layer content in the carrier, and it can be appropriately selected depending on the purpose, but 0.01% to 5.0% by mass is preferred. If the resin layer content is 0.01% by mass or more, a uniform resin layer can be formed on the surface of the core material, and if it is 5.0% by mass or less, the thickness of the resin layer is suppressed, which suppresses fusion between carriers and maintains the uniformity of the carriers.

[0170] <Developer container> A developer container according to one embodiment contains the developer according to one embodiment. The developer container is not particularly limited and can be appropriately selected from known containers, but examples include those having a container body and a cap.

[0171] Furthermore, the size, shape, structure, and material of the container body are not particularly limited, but the shape is preferably cylindrical, with spiral-shaped irregularities formed on the inner surface, allowing the developer contents to move towards the discharge port by rotation, and it is particularly preferable that some or all of the spiral-shaped irregularities have a bellows function. In addition, the material is not particularly limited, but it is preferable that it has good dimensional accuracy, and examples of resin materials include polyester resin, polyethylene resin, polypropylene resin, polystyrene resin, polyvinyl chloride resin, polyacrylic acid, polycarbonate resin, ABS resin, and polyacetal resin.

[0172] The developer container is easy to store and transport, and offers excellent handling, so it can be detachably attached to the image forming apparatus, process cartridge, etc., described later, and used for replenishing the developer.

[0173] <Toner storage unit> A toner storage unit according to one embodiment can store toner according to one embodiment. A toner storage unit according to one embodiment refers to a unit having the function of storing toner, in which toner is stored. Here, examples of the toner storage unit include a toner storage container (container with toner), a developer, and a process cartridge.

[0174] A toner container refers to a container that holds toner.

[0175] A developing unit refers to a device that has the means to store toner and develop it.

[0176] A process cartridge is defined as a device that integrates at least an electrostatic latent image carrier (also called an image carrier) and a developing means, contains toner, and is detachable from an image forming apparatus. The process cartridge may further include at least one selected from a charging unit, an exposure unit, a cleaning unit, etc.

[0177] (Processing cartridge) A process cartridge according to one embodiment is molded to be detachable from various image forming apparatuses and includes an electrostatic latent image carrier that carries an electrostatic latent image, and a developing unit that develops the electrostatic latent image carried on the electrostatic latent image carrier with the developer according to the above embodiment to form a toner image, and may have other configurations as needed.

[0178] The electrostatic latent image carrier is the same as the electrostatic latent image carrier in the image forming apparatus described later, so details will be omitted.

[0179] The developing unit includes a developer container for containing a developer according to one embodiment, and a developer carrier for carrying and transporting the developer contained in the developer container. The developing unit may further include regulating members or the like to regulate the thickness of the carried developer.

[0180] A toner storage unit according to one embodiment houses the toner according to one embodiment, and the toner according to one embodiment has the characteristics of excellent offset resistance, charge stability, stress resistance, and background stain resistance, enabling it to provide high-definition, high-quality images over a long period of time. By mounting the toner storage unit according to one embodiment in an image forming apparatus and forming an image utilizing the characteristics of the toner according to one embodiment, it is possible to form images that have long-term image stability and are of high quality and high definition.

[0181] <Image forming apparatus> An image forming apparatus according to one embodiment includes an electrostatic latent image carrier, an electrostatic latent image forming unit that forms an electrostatic latent image on the electrostatic latent image carrier, and a developing unit that develops the electrostatic latent image formed on the electrostatic latent image carrier using toner to form a toner image, and may further have other configurations as needed.

[0182] In one embodiment, the image forming apparatus more preferably includes, in addition to the electrostatic latent image carrier, electrostatic latent image forming unit and developing unit, a transfer unit for transferring a toner image to a recording medium and a fixing unit for fixing the transferred image onto the surface of the recording medium.

[0183] In the developing section, a toner according to one embodiment is used. Preferably, a developer containing the toner according to one embodiment, and optionally containing other components such as a carrier, may be used to form a toner image.

[0184] (Electrostatic latent image carrier) The material, shape, structure, size, etc., of the electrostatic latent image carrier (sometimes referred to as "electrophotographic photoreceptor" or "photoreceptor") are not particularly limited and can be appropriately selected from known materials. Examples of materials for the electrostatic latent image carrier include inorganic photoreceptors such as amorphous silicon and selenium, and organic photoreceptors (OPC) such as polysilane and phthalopolymethine. Among these, amorphous silicon is preferred in terms of long lifespan, and organic photoreceptors (OPC) are preferred in that they can produce higher-resolution images.

[0185] As amorphous silicon photoreceptors, for example, a photoreceptor having a photoconductive layer made of a-Si can be used by heating the support to 50°C to 400°C and depositing it on the support using methods such as vacuum deposition, sputtering, ion plating, thermal CVD (chemical vapor deposition), photo-CVD, or plasma CVD. Among these, plasma CVD, that is, a method in which a source gas is decomposed by DC, high-frequency, or microwave glow discharge to form an a-Si deposited film on the support, is preferred.

[0186] There are no particular restrictions on the shape of the electrostatic latent image carrier, and it can be appropriately selected depending on the purpose, but a cylindrical shape is preferred. There are no particular restrictions on the outer diameter of the cylindrical electrostatic latent image carrier, and it can be appropriately selected depending on the purpose, but 3 mm to 100 mm is preferred, 5 mm to 50 mm is more preferred, and 10 mm to 30 mm is particularly preferred.

[0187] The linear velocity of the electrostatic latent image carrier is preferably 300 mm / s or higher.

[0188] (Electrostatic latent image formation section) The electrostatic latent image forming unit is not particularly limited as long as it is a means for forming an electrostatic latent image on an electrostatic latent image carrier, and can be appropriately selected according to the purpose. The electrostatic latent image forming unit includes, for example, a charging member (charger) that uniformly charges the surface of the electrostatic latent image carrier, and an exposure member (exposure unit) that exposes the surface of the electrostatic latent image carrier in an image-like manner.

[0189] The charger is not particularly limited and can be appropriately selected according to the purpose, but examples include contact chargers equipped with conductive or semiconductive rolls, brushes, films, rubber blades, etc., and non-contact chargers that utilize corona discharge such as Corotron and Scorotron.

[0190] The shape of the charger can be anything other than a roller, such as a magnetic brush or a fur brush, and can be selected according to the specifications and configuration of the image forming apparatus.

[0191] Preferably, the charger is positioned in contact with or without contact with the electrostatic latent image carrier, and charges the surface of the electrostatic latent image carrier by superimposing DC and AC voltages. Alternatively, it is preferable that the charger is a charging roller positioned in close proximity to the electrostatic latent image carrier via a gap tape, and charges the surface of the electrostatic latent image carrier by superimposing DC and AC voltages on the charging roller.

[0192] While the charger is not limited to a contact-type charger, it is preferable to use a contact-type charging element because it allows for the creation of an image forming apparatus with reduced ozone generation from the charger.

[0193] The exposure device is not particularly limited as long as it can expose the surface of an electrostatic latent image carrier charged by a charger in the manner of the image to be formed, and can be appropriately selected according to the purpose. Examples of exposure devices include copying optical systems, rod lens array systems, laser optical systems, and liquid crystal shutter optical systems.

[0194] There are no particular restrictions on the light source used in an exposure unit, and it can be appropriately selected according to the purpose. Examples include fluorescent lamps, tungsten lamps, halogen lamps, mercury lamps, sodium lamps, light-emitting diodes (LEDs), semiconductor lasers (LDs), electroluminescent devices (ELs), and other types of light-emitting materials.

[0195] Furthermore, various filters such as sharp-cut filters, band-pass filters, near-infrared cut filters, dichroic filters, interference filters, and color temperature conversion filters can be used to illuminate only the desired wavelength range.

[0196] Furthermore, the exposure unit may employ a back-facing method that exposes the electrostatic latent image carrier in an image-like manner from the back side.

[0197] (Developing Department) The developing unit is not particularly limited as long as it can develop the electrostatic latent image formed on the electrostatic latent image carrier to form a visible image, and can be appropriately selected according to the purpose. The developing unit can preferably be one that includes a developer that contains toner and can apply toner to the electrostatic latent image by contact or non-contact, and a developer with a toner container is preferred.

[0198] The developing unit may be a single-color developing unit or a multi-color developing unit. Suitable developing devices include, for example, a developing apparatus that has an agitator that frictionally agitates and charges the toner, a magnetic field generating unit fixed inside, and a rotatable developer carrier (e.g., a magnetic roller) on its surface that carries a developer containing toner.

[0199] (Transfer section) The transfer unit preferably has a primary transfer unit that transfers a visible image onto an intermediate transfer unit to form a composite transfer image, and a secondary transfer unit that transfers the composite transfer image onto a recording medium. The intermediate transfer unit is not particularly limited and can be appropriately selected from known transfer units depending on the purpose, for example, a transfer belt is a suitable example.

[0200] The transfer section (primary transfer means and secondary transfer section) preferably includes at least a transfer device that exfoliates and charges the visible image formed on the electrostatic latent image carrier (photoreceptor) toward the recording medium. There may be one transfer section or two or more.

[0201] Examples of transfer devices include corona discharge transfer devices, transfer belts, transfer rollers, pressure transfer rollers, and adhesive transfer devices.

[0202] While plain paper is typically used as the recording medium, there are no particular restrictions as long as it is capable of transferring the unfixed image after development. Any known recording medium (recording paper) can be appropriately selected according to the purpose, and PET bases for OHPs can also be used.

[0203] (Fixing part) The fixing unit is not particularly limited and can be appropriately selected according to the purpose, but a known heating and pressing unit is preferable. Examples of the heating and pressing unit include a combination of a heating roller and a pressing roller, and a combination of a heating roller, a pressing roller, and an endless belt.

[0204] The fixing unit preferably has a heating body including a heating element, a film in contact with the heating body, and a pressing member that presses against the heating body through the film, and is a heating and pressing unit capable of heating and fixing by passing a recording medium on which an unfixed image is formed between the film and the pressing member.

[0205] For heating in the heating and pressing unit, usually, 80°C to 200°C is preferable.

[0206] The surface pressure in the heating and pressing unit is not particularly limited and can be appropriately selected according to the purpose, but it is preferably 10 N / cm 2 ~80 N / cm 2

[0207] In this embodiment, depending on the purpose, a known optical fuser may be used together with or instead of the fixing unit.

[0208] (Others) The image forming apparatus according to the primary aspect may further include, for example, a charge removing unit, a recycling unit, a control unit, etc.

[0209] ((Charge Removing Unit)) The charge removing unit is not particularly limited as long as it can apply a charge removing bias to the electrostatic latent image carrier, and can be appropriately selected from known charge removing devices. For example, a charge removing lamp is preferably mentioned.

[0210] ((Cleaning Unit)) ​The cleaning unit only needs to be able to remove toner remaining on the electrostatic latent image carrier, and can be appropriately selected from known cleaners. Examples of cleaning units include magnetic brush cleaners, electrostatic brush cleaners, magnetic roller cleaners, blade cleaners, brush cleaners, and web cleaners.

[0211] The primary image forming apparatus can improve cleaning performance by having a cleaning section. Specifically, by controlling the adhesion force between toners, the fluidity of the toner is maintained, thereby improving cleaning performance. Furthermore, by controlling the characteristics of the toner after degradation, excellent cleaning quality can be maintained even under harsh conditions such as extended lifespan and high temperature and humidity. In addition, since the external additive can be sufficiently released from the toner on the photoreceptor, a deposit layer (dam layer) of the external additive can be formed in the cleaning blade nip section, thereby achieving high cleaning performance.

[0212] ((Recycling Department)) The recycling department is not particularly restricted and can use known means of transport, etc.

[0213] ((Control Unit)) The control unit can control the movement of each of the above-mentioned parts. The control unit is not particularly limited as long as it can control the movement of each of the above-mentioned parts, and can be appropriately selected according to the purpose. Examples include control devices such as sequencers and computers.

[0214] The image forming apparatus according to one embodiment can perform image formation using the toner according to one embodiment, and therefore has excellent transferability, electrostatic properties, etc., and can stably provide high-quality images.

[0215] <Image forming method> An image forming method according to one embodiment includes an electrostatic latent image formation step of forming an electrostatic latent image on an electrostatic latent image carrier, and a development step of developing the electrostatic latent image using toner to form a toner image, and may further include other steps as necessary. The image forming method can be suitably carried out by an image forming apparatus, the electrostatic latent image formation step can be suitably carried out by an electrostatic latent image formation unit, the development step can be suitably carried out by a development unit, and the other steps can be suitably carried out by other units.

[0216] Furthermore, the image forming method according to one embodiment more preferably includes, in addition to the electrostatic latent image formation step and the development step described above, a transfer step for transferring a toner image to a recording medium and a fixing step for fixing the transferred image on the surface of the recording medium.

[0217] In the development process, a toner according to one embodiment is used. Preferably, a developer containing the toner according to one embodiment, and optionally containing other components such as a carrier, may be used to form a toner image.

[0218] The electrostatic latent image formation process is a process of forming an electrostatic latent image on an electrostatic latent image carrier, and includes a charging step of charging the surface of the electrostatic latent image carrier and an exposure step of exposing the charged surface of the electrostatic latent image carrier to form an electrostatic latent image. Charging can be performed, for example, by applying a voltage to the surface of the electrostatic latent image carrier using a charger. Exposure can be performed, for example, by exposing the surface of the electrostatic latent image carrier in an image-like manner using an exposure unit. Formation of the electrostatic latent image can be performed, for example, by uniformly charging the surface of the electrostatic latent image carrier and then exposing it in an image-like manner, and can be performed by an electrostatic latent image formation unit.

[0219] The development process is a process of sequentially developing an electrostatic latent image with multiple toners to form a visible image. The formation of the visible image can be done, for example, by developing the electrostatic latent image using toner, and this can be done using a developing unit.

[0220] Inside the developing unit, for example, toner and carrier are mixed and stirred, and the friction during this process causes the toner to become charged. This charge is then held in a pile-like state on the surface of the rotating magnetic roller, forming a magnetic brush. Since the magnetic roller is positioned near the electrostatic latent image carrier (photoreceptor), some of the toner that makes up the magnetic brush formed on the surface of the magnetic roller moves to the surface of the electrostatic latent image carrier (photoreceptor) due to electrical attraction. As a result, the electrostatic latent image is developed by the toner, and a visible image is formed on the surface of the electrostatic latent image carrier (photoreceptor) by the toner.

[0221] The transfer process is a process of transferring a visible image to a recording medium. The transfer process is preferably carried out using an intermediate transfer medium, in which the visible image is first transferred onto the intermediate transfer medium, and then the visible image is secondarily transferred onto the recording medium.

[0222] The transfer process more preferably includes a first transfer step in which a visible image is transferred onto an intermediate transfer medium using two or more toners, preferably full-color toners, to form a composite transfer image, and a second transfer step in which the composite transfer image is transferred onto a recording medium. If the image to be secondarily transferred onto the recording medium is a color image consisting of multiple toners, an intermediate transfer medium may be used to sequentially superimpose each color of toner onto the intermediate transfer medium to form an image on the intermediate transfer medium, and the image on the intermediate transfer medium may be secondarily transferred onto the recording medium all at once using the intermediate transfer medium.

[0223] Transfer can be performed, for example, by charging an electrostatic latent image carrier (photoreceptor) with a transfer charger using a visible image, and this can be done by the transfer unit.

[0224] The fixing process is the process of fixing the visible image transferred to the recording medium using a fixing device. This process may be performed for each color developer after the image is transferred to the recording medium, or it may be performed simultaneously for each color developer in a stacked state.

[0225] The image formation method for the primary form may further include other steps as appropriate, such as static elimination steps, cleaning steps, and recycling steps.

[0226] The static elimination process involves applying a static elimination bias to the electrostatic latent image carrier to remove static electricity, and this can be more effectively performed by the static elimination unit.

[0227] The cleaning process is a process of removing toner remaining on the electrostatic latent image carrier, and can be performed more effectively by the cleaning unit.

[0228] The recycling process involves recycling the toner removed during the cleaning process into the developing unit, and can be performed more effectively in the recycling unit.

[0229] The image forming method according to one embodiment can perform image formation using the toner according to one embodiment, and therefore has excellent transferability, electrostatic properties, etc., and can stably provide high-quality images.

[0230] [An embodiment of an image forming apparatus] Next, one aspect of an image forming apparatus according to one embodiment will be described with reference to Figure 2. Figure 2 is a schematic configuration diagram showing an example of an image forming apparatus according to one embodiment. As shown in Figure 2, the image forming apparatus 100A comprises a photosensitive drum 10 which is an electrostatic latent image carrier, a charging roller 20 which is a charging unit, an exposure unit 30 which is an exposure unit, a developing unit 40 which is a developing unit, an intermediate transfer body (intermediate transfer belt) 50, a cleaning unit 60 which is a cleaning unit, a transfer roller 70 which is a transfer unit, a static elimination lamp 80 which is a static elimination unit, and an intermediate transfer body cleaning unit 90.

[0231] The intermediate transfer body 50 is an endless belt stretched by three rollers 51 located on its inside, and is designed to be movable in the direction of the arrow by the three rollers 51. Some of the three rollers 51 also function as transfer bias rollers capable of applying a predetermined transfer bias (primary transfer bias) to the intermediate transfer body 50. An intermediate transfer body cleaning device 90 is located near the intermediate transfer body 50. Furthermore, a transfer roller 70 is located near the intermediate transfer body 50, facing the intermediate transfer body 50, and can apply a transfer bias (secondary transfer bias) for transferring the developed image (toner image) to the transfer paper P, which is the recording medium (secondary transfer). Around the intermediate transfer body 50, a corona charger 52 for imparting charge to the toner image on the intermediate transfer body 50 is located between the contact area between the photoreceptor drum 10 and the intermediate transfer body 50, and between the intermediate transfer body 50 and the transfer paper P, with respect to the rotation direction of the intermediate transfer body 50.

[0232] The developing apparatus 40 consists of a developing belt 41, which is a developer carrier, and a developing unit 42 that is arranged around the developing belt 41.

[0233] The developing belt 41 is an endless belt stretched by multiple belt rollers and can move in the direction of the arrow in the figure. Furthermore, a portion of the developing belt 41 is in contact with the photoreceptor drum 10.

[0234] The developing unit 42 consists of a black (Bk) developing unit 42K, a yellow (Y) developing unit 42Y, a magenta (M) developing unit 42M, and a cyan (C) developing unit 42C.

[0235] The black developing unit 42K comprises a developer container 421K, a developer supply roller 422K, and a developing roller (developer carrier) 423K. The yellow developing unit 42Y comprises a developer container 421Y, a developer supply roller 422Y, and a developing roller 423Y. The magenta developing unit 42M comprises a developer container 421M, a developer supply roller 422M, and a developing roller 423M. The cyan developing unit 42C comprises a developer container 421C, a developer supply roller 422C, and a developing roller 423C.

[0236] Next, a method for forming an image using the image forming apparatus 100A will be described. First, the surface of the photoreceptor drum 10 is uniformly charged using the charging roller 20, and then the photoreceptor drum 10 is exposed to exposure light L using the exposure apparatus 30 to form an electrostatic latent image. Next, the electrostatic latent image formed on the photoreceptor drum 10 is developed with toner supplied from the developing apparatus 40 to form a toner image. Furthermore, the toner image formed on the photoreceptor drum 10 is transferred (primary transfer) onto the intermediate transfer body 50 by a transfer bias applied from the roller 51, and then transferred (secondary transfer) onto the transfer paper P fed by a paper feeding unit (not shown) by a transfer bias applied from the transfer roller 70. Meanwhile, the photoreceptor drum 10 on which the toner image has been transferred to the intermediate transfer body 50 is de-static by the static elimination lamp 80 after the toner remaining on the surface is removed by the cleaning apparatus 60. The remaining toner on the intermediate transfer body 50 after image transfer is removed by the intermediate transfer body cleaning apparatus 90.

[0237] After the transfer process is complete, the transfer paper P is transported to the fixing unit, where the transferred toner image is fixed to the transfer paper P.

[0238] Figure 3 is a schematic diagram showing another example of an image forming apparatus according to one embodiment. As shown in Figure 3, the image forming apparatus 100B has the same configuration as the image forming apparatus 100A shown in Figure 2, except that the developing belt 41 is not provided and the developing units 42 (black developing unit 42K, yellow developing unit 42Y, magenta developing unit 42M, and cyan developing unit 42C) are arranged directly opposite each other around the photoreceptor drum 10.

[0239] Figure 4 is a schematic diagram showing another example of an image forming apparatus according to one embodiment. As shown in Figure 4, the image forming apparatus 100C is a tandem-type color image forming apparatus and includes a copy device body 110, a paper feed table 120, a scanner 130, an automatic document feeder (ADF) 140, a secondary transfer device 150, a fixing unit which is a fixing device 160, and a sheet reversing device 170.

[0240] An endless belt-shaped intermediate transfer body 50 is provided in the center of the main body 110 of the copying device. The intermediate transfer body 50 is an endless belt stretched over three rollers 53A, 53B, and 53C, and can move in the direction of the arrow in Figure 4. Near roller 53B, an intermediate transfer body cleaning device 90 is arranged to remove toner remaining on the intermediate transfer body 50 after the toner image has been transferred to the recording paper. Opposite the intermediate transfer body 50 stretched by rollers 53A and 53B, and along the transport direction, are two tandem-type developing units, which are image forming units 42 (yellow (Y) developing unit 42Y, cyan (C) developing unit 42C, magenta (M) developing unit 42M, and black (Bk) developing unit 42K).

[0241] Furthermore, an exposure device 30 is located near the image forming unit 42. In addition, a secondary transfer device 150 is located on the side of the intermediate transfer body 50 opposite to the side where the image forming unit 42 is located. The secondary transfer device 150 includes a secondary transfer belt 151. The secondary transfer belt 151 is an endless belt stretched over a pair of rollers 152, and the recording paper and the intermediate transfer body 50 being transported on the secondary transfer belt 151 can come into contact between the roller 53C and the roller 152.

[0242] Furthermore, a fixing device 160 is positioned near the secondary transfer belt 151. The fixing device 160 comprises a fixing belt 161, which is an endless belt stretched over a pair of rollers, and a pressure roller 162 that is positioned under pressure from the fixing belt 161.

[0243] Furthermore, a sheet reversing device 170 is positioned near the secondary transfer belt 151 and the fixing device 160 to reverse the recording paper when forming an image on both sides of the recording paper.

[0244] Next, a method for forming a full-color image using the image forming apparatus 100C will be described. First, a color document is placed on the document glass 141 of the automatic document feeder (ADF) 140, or the automatic document feeder 140 is opened and the color document is placed on the contact glass 131 of the scanner 130, and the automatic document feeder 140 is closed.

[0245] When the start switch (not shown) is pressed, if a color document is placed in the automatic document transporter 140, the color document is transported and moved onto the contact glass 131, after which the scanner 130 is driven and the first and second traveling bodies 132 and 133, which are equipped with light sources, move. On the other hand, if a document is placed on the contact glass 131, the scanner 130 is driven immediately and the first and second traveling bodies 132 and 133, which are equipped with light sources, move. At this time, the light emitted from the first traveling body 132 is reflected from the document surface by the mirror of the second traveling body 133, and then received by the reading sensor 136 through the imaging lens 135, thereby reading the color document (color image) and obtaining image information in black, yellow, magenta, and cyan.

[0246] Image information for each color is transmitted to the respective color developing units (yellow developing unit 42Y, cyan developing unit 42C, magenta developing unit 42M, and black developing unit 42K), and toner images for each color are formed.

[0247] Figure 5 is a partially enlarged view of the image forming apparatus shown in Figure 4. As shown in Figure 5, each developing unit (yellow developing unit 42Y, cyan developing unit 42C, magenta developing unit 42M, and black developing unit 42K) comprises a photoreceptor drum 10 (static photoreceptor drum 10K for black, photoreceptor drum 10Y for yellow, photoreceptor drum 10M for magenta, and photoreceptor drum 10C for cyan), a charging roller 20 which is a charging unit that uniformly charges the photoreceptor drum 10, an exposure device 30 which exposes the photoreceptor drum 10 with exposure light L based on image information for each color and forms an electrostatic latent image of each color on the photoreceptor drum 10, a developing device 40 which is a developing unit that develops the electrostatic latent image with a developer of each color to form a toner image of each color, a transfer charger 62 for transferring the toner image onto an intermediate transfer body 50, a cleaning device 60, and an anti-static lamp 80.

[0248] The toner images of each color formed by the respective color developing units (yellow developing unit 42Y, cyan developing unit 42C, magenta developing unit 42M, and black developing unit 42K) are sequentially transferred (primary transfer) onto an intermediate transfer body 50 that is stretched and moved on rollers 53A, 53B, and 53C. Then, the toner images of each color are superimposed on the intermediate transfer body 50 to form a composite color image (color transfer image).

[0249] Meanwhile, in the paper feed table 120, one of the paper feed rollers 121 is selectively rotated to feed recording paper from one of the paper cassettes 123 arranged in multiple stages in the paper bank 122. The recording paper is separated one sheet at a time by the separation roller 124 and sent to the paper feed path 125, transported by the transport roller 126 and guided to the paper feed path 111 in the main body of the copier 110, where it is stopped by the registration roller 112. Alternatively, the manual feed roller 113 is rotated to feed recording paper from the manual feed tray 114, separates it one sheet at a time by the manual feed roller 113 and guides it to the manual feed path 115, where it is stopped by the registration roller 112.

[0250] Although the registration roller 112 is generally used with grounding, it may also be used with a bias applied to remove paper dust from the recording paper.

[0251] Next, the register roller 112 is rotated in time with the composite color image (color transfer image) formed on the intermediate transfer body 50, and recording paper is fed between the intermediate transfer body 50 and the secondary transfer belt 151 to transfer the composite color image (color transfer image) onto the recording paper (secondary transfer). Any toner remaining on the intermediate transfer body 50 onto which the composite color image (color transfer image) has been transferred is removed by the intermediate transfer body cleaning device 90.

[0252] After the composite color image (color transfer image) is transferred to the recording paper, it is transported by the secondary transfer belt 151, and then the composite toner image is fixed onto the recording paper by the fixing device 160.

[0253] Thereafter, the recording paper is discharged onto the paper discharge tray 118 by the discharge roller 117 after the conveyance path is switched by the switching claw 116. Alternatively, the recording paper is discharged onto the paper discharge tray 118 by the discharge roller 117 after the conveyance path is switched by the switching claw 116, reversed by the sheet reversing device 170, guided again to the secondary transfer belt 151, and an image is formed on the back surface in the same manner and then discharged onto the paper discharge tray 118 by the discharge roller 117.

[0254] The developing unit includes a developer storage container that stores a developer according to an embodiment, and a developer carrier that carries and conveys the developer stored in the developer storage container. Note that the developing unit may further include a regulating member or the like in order to regulate the thickness of the developer to be carried.

[0255] [One Aspect of the Process Cartridge] One aspect of the process cartridge will be described with reference to FIG. 6. FIG. 6 is a diagram showing an example of a process cartridge according to an embodiment. As shown in FIG. 6, the image forming apparatus process cartridge 200 includes a photosensitive drum 10, a corona charger which is a charging unit 22, a developing device 40, a cleaning device 60, and a transfer roller 70. In the figure, P indicates transfer paper, and L indicates exposure light.

Example

[0256] Hereinafter, the embodiments will be described more specifically by showing examples and comparative examples, but the embodiments are not limited to these examples and comparative examples.

[0257] [Manufacture of Toner] [Example 1] [Synthesis of Amorphous Polyester Resin (Binder Resin)] Reaction 1: In a reaction vessel equipped with a nitrogen introduction tube, a dehydrating tube, a stirrer, and a thermocouple, 3 mol adduct of bisphenol A ethylene oxide (EO) and 1,2-propylene glycol (PG) were charged at a molar ratio of 90 / 10, terephthalic acid (TPA) and adipic acid (APA) were charged at a molar ratio of 70 / 30, and OH / COOH = 1.33, and reacted at 230 ° C for 10 hours at normal pressure together with 500 ppm of titanium tetraisopropoxide. Reaction 2: Next, the reaction was carried out for 5 hours under reduced pressure of 10 mmHg to 15 mmHg. Reaction 3: Next, 10 parts by mass of trimellitic anhydride (TMA) were added to the reaction vessel and reacted at 180°C and atmospheric pressure for 3 hours to obtain an amorphous polyester resin. The amorphous polyester resin had a number average molecular weight of 2300, a weight average molecular weight of 6000, a Tg of 47°C, and an acid value of 18 mgKOH / g.

[0258] (Synthesis of crystalline polyesters) In a 5-liter four-necked flask equipped with a nitrogen inlet tube, dehydration tube, stirrer, and thermocouple, 2010 g of 1,4-butanediol, 2520 g of fumaric acid, 285 g of trimellitic anhydride, and 4.9 g of hydroquinone were added and reacted at 160°C for 6 hours, then the temperature was raised to 200°C and the reaction continued for 2 hours, followed by a reaction at 8.3 kPa for 1 hour to obtain a crystalline polyester resin. The endothermic peak temperature of the DSC was 76°C, Mn was 2500, and Mw was 16000. The endothermic shoulder temperature was 54°C.

[0259] (Preparation of crystalline polyester dispersion) 100 parts by mass of crystalline polyester resin and 400 parts by mass of ethyl acetate were placed in a 2L metal container, heated and dissolved at 70°C, and then cooled to 20°C in an ice bath at a rate of 20°C / min. Observation of the cooled liquid confirmed that the crystalline polyester had recrystallized. After cooling, 100 parts by mass of amorphous polyester resin was dissolved in the dispersion, 500 mL of glass beads (3 mmφ) were added, and the mixture was ground for 10 hours using a batch-type sand mill (manufactured by Kanpe Hapio Co., Ltd.) to obtain a crystalline polyester dispersion with a volume-average particle size of 0.3 μm. The maximum slurry temperature during grinding was 30°C.

[0260] (Synthesis of prepolymers) In a reaction vessel equipped with a condenser, a stirrer, and a nitrogen inlet tube, 682 parts by mass of bisphenol A ethylene oxide 2 molar adduct, 81 parts by mass of bisphenol A propylene oxide 2 molar adduct, 283 parts by mass of terephthalic acid, 22 parts by mass of trimellitic anhydride, and 2 parts by mass of dibutyltin oxide were added. The mixture was reacted at atmospheric pressure at 230°C for 8 hours, and then further reacted under reduced pressure of 10 mmHg to 15 mmHg for 5 hours to obtain an intermediate polyester resin. The obtained intermediate polyester resin had a number-average molecular weight of 2,100, a weight-average molecular weight of 9,500, a glass transition temperature (Tg) of 55°C, an acid value of 0.5 mg KOH / g, and a hydroxyl value of 51 mg KOH / g. Next, 410 parts by mass of [intermediate polyester resin], 89 parts by mass of isophorone diisocyanate, and 500 parts by mass of ethyl acetate were added to a reaction vessel equipped with a condenser, a stirrer, and a nitrogen inlet tube, and reacted at 100°C for 5 hours to obtain a [prepolymer]. The free isocyanate percentage of the obtained [prepolymer] was 1.53%.

[0261] (Preparation of release agent dispersion) 70 parts by mass of carnauba wax (WA-05, manufactured by Cerarica Noda Co., Ltd.) and 140 parts by mass of polyester resin and 290 parts by mass of ethyl acetate were placed in a container equipped with a stirring rod and thermometer. The mixture was heated to 75°C under stirring and maintained at 75°C for 1.5 hours, then cooled to 30°C in 1 hour. Dispersion was performed using a bee mill (Ultraviscomil, manufactured by AIMEX Co., Ltd.) under the following conditions: liquid transfer rate of 5 kg / hr, disk peripheral speed of 6 m / sec, 0.5 mm zirconia beads filled to 80 volume%, and 3 passes, to obtain a release agent dispersion.

[0262] (Preparation of colorant masterbatch) 1,000 parts by mass of water, 1,000 parts by mass of CI pigment blue 15:3, and 1,000 parts by mass of [polyester resin] were added and mixed in a Henschel mixer (manufactured by Mitsui Mining Co., Ltd.). The mixture was kneaded at 150°C for 30 minutes using two rolls, then rolled and cooled, and pulverized in a pulperizer to obtain [coloring agent masterbatch 1].

[0263] (Preparation of oil phase 1) In a container equipped with a thermometer and a stirrer, 60 parts by mass of [polyester resin], 10 parts by mass of [crystalline polyester dispersion], 113 parts by mass of [release agent dispersion], 68 parts by mass of [coloring agent masterbatch 1], 1.0 part by mass of a montmorillonite compound modified with a quaternary ammonium salt having at least a portion of a benzyl group (Krayton APA, manufactured by Southern Clay Products, particle size 500 nm), and 122 parts by mass of ethyl acetate were placed and dispersed using a shear disperser (TK Homomixer) at a peripheral speed of 12.5 m / sec. Then, using a bead mill (Ultraviscomill, manufactured by AIMEX), dispersion was performed under the conditions of a liquid transfer speed of 5 kg / hr, a disk peripheral speed of 10 m / sec, and 80 volume% of 0.5 mm zirconia beads packed in 3 passes to obtain [oil phase 1].

[0264] (Manufacturing of aqueous dispersion of resin microparticles) In a reaction vessel equipped with a stirring rod and thermometer, 600 parts by mass of water, 120 parts by mass of styrene, 100 parts by mass of methacrylic acid, 45 parts by mass of butyl acrylate, 10 parts by mass of sodium alkylallyl sulfosuccinate (Eleminol JS-2, manufactured by Sanyo Chemical Industries, Ltd.), and 1 part by mass of ammonium persulfate were charged and stirred at 400 rpm for 20 minutes, yielding a white emulsion. This emulsion was heated to a system temperature of 75°C and reacted for 6 hours. Further, 30 parts by mass of a 1% aqueous solution of ammonium persulfate was added and aged at 75°C for 6 hours to obtain an aqueous dispersion of resin microparticles. The volume-average particle size of the particles contained in this aqueous dispersion of resin microparticles was 60 nm, the weight-average molecular weight of the resin was 140,000, and the Tg was 73°C.

[0265] (Preparation of the aqueous phase) 990 parts by mass of water, 83 parts by mass of [aqueous dispersion of resin fine particles], 37 parts by mass of a 48.5% aqueous solution of sodium dodecyldiphenyl ether disulfonate (Eleminol MON-7, manufactured by Sanyo Chemical Industries, Ltd.), and 90 parts by mass of ethyl acetate were mixed and stirred to obtain the [aqueous phase].

[0266] (emulsification or dispersion) 77 parts by mass of an ethyl acetate solution of [prepolymer] and 2.5 parts by mass of a 50% ethyl acetate solution of isophoronediamine were added to 374 parts by mass of [oil phase 1], and the mixture was stirred at 5,000 rpm using a TK type homomixer (manufactured by Tokushu Kika Co., Ltd.) to dissolve and disperse uniformly to obtain [oil phase 1']. Next, 550 parts by mass of [aqueous phase] was placed in another container equipped with a stirrer and a thermometer, and [oil phase 1'] was added while stirring at 11,000 rpm using a TK type homomixer (manufactured by Tokushu Kika Kogyo Co., Ltd.), and emulsified for 1 minute to obtain [emulsion slurry 1].

[0267] (Desolventization ~ Washing ~ Drying) (1) [Emulsion slurry 1] was charged into a container equipped with a stirrer and a thermometer, and desolventized at 30 °C for 8 hours under reduced pressure to obtain [slurry 1]. After holding the obtained [slurry 1] at 45 °C for 2 hours, it was filtered under reduced pressure, and the following washing treatment was performed. (1) 100 parts by mass of ion-exchanged water was added to the filter cake, mixed with a TK homomixer (rotating speed: 6,000 rpm for 5 minutes), and then filtered.

[0268] (2) 100 parts by mass of ion-exchanged water was added to the filter cake of (1), mixed with a TK homomixer (rotating speed: 6,000 rpm for 5 minutes), and then 1% hydrochloric acid was added under stirring until the pH reached about 3.3, and stirring was continued for 1 hour in that state and then filtered.

[0269] (3) The operation of adding 300 parts by mass of ion-exchanged water to the filter cake of (2), mixing with a TK homomixer (rotating speed: 6,000 rpm for 5 minutes), and then filtering was performed twice to obtain filter cake 1.

[0270] The obtained filter cake 1 was dried at 40 °C for 48 hours using a circulating air dryer. Then, it was sieved with a 75 μm mesh sieve to produce [toner mother particles 1].

[0271] (Mixing) To the above [Toner matrix particles 1], 1.5 parts by mass of hydrophobic silica (HDK-2000, manufactured by Wacker Chemie) was added per 100 parts by mass of matrix particles, and the mixture was mixed for 5 minutes at a peripheral speed of 33 m / s in a 20 L Henschel mixer (manufactured by Mitsui Mining Co., Ltd.). The mixture was then sieved through a 500 mesh sieve to obtain [Toner 1].

[0272] In [Toner 1], the percentage of particles in which the number of domains with a maximum diameter of 2.0 μm or more of the constituent elements of the inorganic filler is 10% or less of the total number of toner particles (the percentage of domains with a maximum diameter of 2.0 μm or more of the constituent elements of the inorganic filler), the acid value, the volume-average particle size, and the ratio of the volume-average particle size to the number-average particle size (volume-average particle size / number-average particle size) were measured.

[0273] (Proportion of domains in inorganic fillers where the maximum diameter of the constituent elements is 2.0 μm or larger) Samples of toner fixed on carbon tape and coated with carbon to prevent charge-up were observed using SEM and EDX. The observation conditions were as follows: a Hitachi SU8230 SEM and a Bruker XFLash FLatQUAD 5060F EDX scanner were used, with an acceleration voltage of 3-10kV (appropriate voltage selected depending on the filler type) and a magnification of 4000x. EDX images of at least 20 toner particles, each containing one of the constituent elements of the inorganic filler used in toner production, were obtained. These detected images of the element were then edited using image editing software (Asahi Kasei Engineering's "A-Image-kun").

[0274] -Scale settings- From the "Image Input / Output" tab, I loaded the image to be analyzed, and then used the "New Scale Setting" button to set the scale for this image based on the scale bar in the image.

[0275] -Image Processing- For color images, I selected "Color Image Analysis" from the "Image Analysis" tab, performed the appropriate conversion, selected the image with the clearest contrast, and converted it to a black and white image. Then, I selected the "Laplacian Filter" process from the "Image Quality Improvement" tab to enhance the image edges and reduce blur.

[0276] -Calculation of inorganic filler domain diameter- [Image processing] From the "Image Analysis" tab, I selected "Particle Analysis". For the binarization method and correction method, I selected "Manual", and for the small shape removal area, I set it appropriately so that small particles were not removed, and then pressed the "Execute" button. I determined an appropriate threshold while comparing it with the original image and performed binarization. If, in the binarized image, multiple particles were incorrectly identified as a single particle, I manually corrected it while comparing it with the original image and pressed the "Finish" button. From the obtained results, I determined the maximum diameter for each domain of inorganic filler within a single toner particle, counted the number of toner particles in which the maximum diameter of any constituent element of the inorganic filler was 2.0 μm or larger, and determined whether the proportion of toner particles in which domains with a maximum diameter of 2.0 μm or larger were present was 10% or less of the total number of particles observed.

[0277] (Acid value) The acid value of the toner was measured in accordance with JIS K0070-1992. Specifically, 0.5 g of the sample (0.3 g of the ethyl acetate-soluble portion) was first added to 120 mL of toluene and dissolved by stirring at 23°C for approximately 10 hours. Next, 30 mL of ethanol was added to prepare the sample solution. If the sample did not dissolve, solvents such as dioxane or tetrahydrofuran were used. Furthermore, the acid value was measured at 23°C using a potentiometric automatic titrator (DL-53 Titrator, Mettler-Toledo) and an electrode (DG113-SC, Mettler-Toledo), and the analysis was performed using the analysis software LabX Light Version 1.00.000. A mixed solvent of 120 mL of toluene and 30 mL of ethanol was used for calibration of the instrument.

[0278] (Volume-average particle size) 0.5 mL of a 10% by mass aqueous solution of surfactant (alkylbenzene sulfonate, Neogen SC-A, manufactured by Daiichi Kogyo Seiyaku Co., Ltd.) was added to a 100 mL glass beaker, 0.5 g of each toner was added and stirred with a micro spatula, and then 80 mL of deionized water was added to obtain a toner sample dispersion. The toner sample dispersion was added dropwise to achieve a concentration of (8 ± 2)%. The obtained toner sample dispersion was dispersed for 10 minutes using an ultrasonic disperser (W-113MK-II, manufactured by Honda Electronics Co., Ltd.). The dispersion was measured using a particle size analyzer ("Multisizer III," manufactured by Beckman Coulter) with Isoton III (manufactured by Beckman Coulter) as the measurement solution at an aperture diameter of 100 μm, and the volume-average particle size of the toner was measured by analyzing the toner with analysis software (Beckman CoulterMutLisizer 3 Version 3.51).

[0279] (Volume-average particle size / Number-average particle size) The (volume-average particle size / number-average particle size) of the toner was calculated using the same method as described above for measuring the toner volume-average particle size.

[0280] [Example 2] Toner 2 was prepared in the same manner as in Example 1, except that 14 parts by mass of trimellitic anhydride (TMA) were added to the amorphous polyester resin in Example 1, changing the acid value to 27 mg KOH / g.

[0281] [Example 3] Toner 3 was prepared in the same manner as in Example 1, except that 19 parts by mass of trimellitic anhydride (TMA) were added to the amorphous polyester resin in Example 1, changing the acid value to 27 mg KOH / g.

[0282] [Example 4] Toner 4 was prepared in the same manner as in Example 1, except that in the preparation of the amorphous polyester resin in Example 1, 13 parts by mass of trimellitic anhydride (TMA) was added to change the acid value to 25 mg KOH / g, and in the preparation of the oil phase 1, the amount of montmorillonite compound was changed to 0.2 parts by mass.

[0283] [Example 5] Toner 5 was prepared in the same manner as in Example 2, except that the amount of crystalline polyester dispersion and montmorillonite compound were changed to 2 parts by mass and 1.5 parts by mass respectively in the preparation of oil phase 1 in Example 2.

[0284] [Comparative Example 1] (Preparation of organically modified inorganic filler masterbatch) 100 parts by mass of polyester resin, 100 parts by mass of a montmorillonite compound modified with a quaternary ammonium salt having at least a portion of a benzyl group (Clayton APA, manufactured by Southern Clay Products, particle size 500 nm), and 50 parts by mass of deionized water were thoroughly mixed and kneaded in an open-roll type kneader (NIDEX / manufactured by Mitsui Mining Co., Ltd.). Kneading was started at a temperature of 90°C and then gradually cooled to 50°C to prepare an organically modified inorganic filler masterbatch with a resin-to-layer inorganic mineral ratio (mass ratio) of 1:1. Toner 6 was prepared in the same manner as in Example 1, except that in the preparation of Oil Phase 1 in Example 1, 1.0 part by mass of montmorillonite compound was replaced with 2.0 parts by mass of organically modified inorganic filler masterbatch.

[0285] [Comparative Example 2] In the preparation of the amorphous polyester resin in Example 1, toner 7 was prepared in the same manner as in Example 1, except that 6 parts by mass of trimellitic anhydride (TMA) were added to change the acid value to 9 mg KOH / g.

[0286] [Comparative Example 3] Toner 8 was prepared in the same manner as in Example 3, except that the montmorillonite compound was not added to the oil phase 1.

[0287] [Comparative Example 4] Toner 9 was prepared in the same manner as in Example 3, except that the crystalline polyester dispersion was not added to the oil phase 1.

[0288] [Comparative Example 5] Toner 10 was prepared in the same manner as in Example 3, except that the montmorillonite compound and crystalline polyester dispersion were not added to the oil phase 1.

[0289] The toner manufacturing conditions and results obtained as described above are shown in Table 1.

[0290] [Table 1]

[0291] <Evaluation Criteria> The toners and their developers obtained in the above examples and comparative examples were evaluated as follows.

[0292] [Preparation of developer] Five parts by mass of [toner 1] and 95 parts by mass of the carrier described below were mixed in a turbler shaker mixer (manufactured by Synmaru Enterprises) to obtain a developer. (Career creation) Silicone resin (organostraight silicone) 100 parts by mass Toluene 100 parts by mass 5 parts by mass of γ-(2-aminoethyl)aminopropyltrimethoxysilane Carbon black 10 parts by mass

[0293] The above mixture was dispersed in a homomixer for 20 minutes to prepare a coating layer forming solution. This coating layer forming solution was then coated onto the surface of 1000 parts by mass of spherical magnetite with a particle size of 50 μm using a fluidized bed coating apparatus to obtain magnetic carriers.

[0294] Using an image forming apparatus containing [toner 1] and [developer 1], the toner manufacturing yield, image transferability, and resistance to internal contamination were evaluated according to the evaluation method described below. [Developer 2] to [toner 10] were also prepared using the same manufacturing procedure.

[0295] [Toner manufacturing yield] The results were categorized as follows: "A" if, even without removing fine and coarse particles from the obtained toner through classification, an image free of unintended dust and unevenness could be obtained in the solid image formed with the developer; "B" if there was no dust image caused by fine toner particles, but only the coarse particles needed to be removed by classification in the image where unintended unevenness was caused by coarse particles; and "C" if there was a large amount of both fine and coarse particles, resulting in an image with unintended dust and unevenness.

[0296] [Transferability] Using a Ricoh Imagio MP 7501 copier (manufactured by Ricoh Co., Ltd.) tuned to a line speed of 162 mm / sec and a transfer time of 40 msec, a running test was conducted for each of the [Developer 1] to [Developer 10] by outputting a solid A4 size pattern with a toner deposition amount of 0.6 mg / cm2 as a test image. The transfer efficiency in the primary transfer was determined using the following formula (Equation 2) and the transfer efficiency in the secondary transfer was determined using the following formula (Equation 3) for the initial test image and after 100K output. The evaluation criteria are as follows. Primary transfer efficiency (%) = (Amount of toner transferred onto the intermediate transfer medium / Amount of toner developed onto the electrophotographic photoreceptor) × 100 ... (Equation 2) Secondary transfer efficiency (%) = [(Amount of toner transferred onto the intermediate transfer material - Amount of toner remaining on the intermediate transfer material) / Amount of toner transferred onto the intermediate transfer material] × 100 ... (Equation 3) The overall transcription rate was calculated by multiplying the primary transcription rate and the secondary transcription rate. A transcription rate of 97.0% or higher was classified as "A," a transcription rate of 93.0% to 97.0% as "B," and a transcription rate of less than 93.0% as "C."

[0297] [Evaluation of resistance to internal contamination] [Developer 1] to [Developer 10] were each tested using a modified Ricoh digital color imagio Neo C600. After running 100,000 image charts with a 50% image area in single-color mode, the prints and the area around the fuser / paper output section were visually inspected and evaluated by comparing them to three graded samples: A, B, and C. A, B, and C indicate increasing levels of contamination in the prints and around the fuser / paper output section. A C rating indicates unacceptable levels of contamination in both the fuser area and the prints, making the product unsuitable for use.

[0298] (Heat-resistant storage stability) After storing the toner at 50°C for 8 hours, it was sieved through a 42-mesh sieve for 2 minutes, and the remaining percentage on the mesh was measured. In this test, the better the heat resistance of the toner, the lower the remaining percentage. Heat resistance was judged as follows: a remaining percentage of less than 10% was rated "A", a remaining percentage of 10% to less than 30% was rated "B", and a remaining percentage of 30% or more was rated "C".

[0299] (Low temperature fixation) Using a tandem full-color image forming apparatus, transfer paper (manufactured by Ricoh Business Expert Co., Ltd., copy printing paper) is used. <70> ) Above, the amount of toner deposited after transfer is 0.85±0.10 mg / cm 2 A solid image (image size 3cm x 8cm) was created on the entire surface of the paper. Fixing was performed by varying the temperature of the fixing belt. The surface of the obtained fixed image was drawn on using a drawing tester AD-401 (manufactured by Ueshima Seisakusho Co., Ltd.) with a ruby ​​needle (tip radius 260μmR~320μmR, tip angle 60 degrees) and a load of 50g. The drawn surface was rubbed strongly 5 times with a fiber (Honeycot #440, manufactured by Hanilon Co., Ltd.), and the fixing belt temperature at which almost no image abrasion was removed was defined as the lower fixing limit temperature. The solid image was created on the transfer paper at a position 3.0cm from the leading edge in the paper feeding direction. The speed at which the paper passed through the nip section of the fixing device was 280mm / s. The lower the fixing limit temperature, the better the low-temperature fixing performance. Those with a fixing limit temperature of less than 105℃ were classified as "A", those between 105℃ and 115℃ were classified as "B", and those above 115℃ were classified as "C".

[0300] As shown in Table 1, Examples 1 to 5 achieve high levels of toner manufacturing yield, transferability, resistance to in-machine contamination, heat resistance, and fixing limit. On the other hand, Comparative Examples 1 to 5 show low levels in one or more of the following areas, or one of these areas presents practical problems.

[0301] Therefore, unlike the toners of Comparative Examples 1 to 5, the toners of Examples 1 to 5 contain a binder resin, an inorganic filler, and a crystalline polyester resin. When the particle cross-section of the toner is observed with SEM-EDX and the constituent elements of the inorganic filler are mapped, the proportion of particles containing domains with a maximum diameter of 2.0 μm or more of the inorganic filler is 10% or less of the total number of observed particles. The volume-average particle size of the toner is 5.9 μm or less, and the (volume-average particle size / number-average particle size) is 1.15 or less. As a result, it can be said that high-quality toners with excellent transferability, resistance to in-machine contamination, heat resistance, and low-temperature fixing properties can be manufactured without reducing the manufacturing yield.

[0302] As described above, embodiments have been explained, but these embodiments are presented as examples only, and the present invention is not limited by these embodiments. The above embodiments can be implemented in various other forms, and various combinations, omissions, substitutions, and modifications are possible without departing from the spirit of the invention. These embodiments and their variations are included in the scope and spirit of the invention, as well as in the claims of the invention and its equivalents. [Explanation of symbols]

[0303] 1A, 1B, 1C Image forming device 10. Electrostatic latent image carrier (photoreceptor drum) 20. Charging roller (charging part) 30 Exposure apparatus (exposure unit) 40. Developing device (developing unit) 50 Intermediate transfer material (intermediate transfer belt) 60 Cleaning device (cleaning section) 70 Transfer roller (transfer section) 80 Static elimination lamp (static elimination unit) [Prior art documents] [Patent Documents]

[0304] [Patent Document 1] Japanese Patent Publication No. 2016-45394

Claims

1. A toner containing a binder resin, an inorganic filler containing any of Al, Si, Fe, Ca, Mg, and Ti, and a crystalline polyester resin, When the particle cross-section of the toner is observed and the constituent elements of Al, Si, Fe, Ca, Mg, and Ti that constitute the inorganic filler are mapped, the proportion of particles in which a domain with a maximum diameter of any of the constituent elements of the inorganic filler is 2.0 μm or more is 10% or less of the total number of particles of the observed toner. The volume-average particle size of the toner is 6.0 μm or less. The ratio of volume-average particle size to number-average particle size (volume-average particle size / number-average particle size) is 1.15 or less. A toner in which the inorganic filler is an inorganic layered compound of any of the following: smectite group clay minerals, kaolin group clay minerals, bentonite, attapulgite, magadianite, and kanemite.

2. The toner according to claim 1, characterized in that the (volume average particle size / number average particle size) for the toner is 1.10 to 1.

13.

3. The toner according to claim 1 or 2, wherein the volume-average particle size is 4.0 μm to 5.5 μm.

4. The toner according to any one of claims 1 to 3, wherein the acid value of the toner is 10 mg KOH / g to 30 mg KOH / g.

5. A developer comprising the toner described in any one of claims 1 to 4 and a carrier.

6. A toner storage unit containing the toner described in any one of claims 1 to 4.

7. An electrostatic latent image carrier and a developing unit are integrally supported, which develops the electrostatic latent image formed on the electrostatic latent image carrier to form a visible image using the toner described in any one of claims 1 to 4 or the developer described in claim 5. A process cartridge that can be attached to and detached from the main body of an image forming apparatus.

8. Electrostatic latent image carrier, An electrostatic latent image forming unit that forms an electrostatic latent image on the electrostatic latent image carrier, A developing unit that develops the electrostatic latent image to form a visible image using the toner described in any one of claims 1 to 4 or the developer described in claim 5, A transfer unit that transfers the visible image onto a recording medium, A fixing unit for fixing the transferred image onto the recording medium, An image forming apparatus equipped with the following features.

9. An electrostatic latent image formation step in which an electrostatic latent image is formed on an electrostatic latent image carrier, A developing step of developing the electrostatic latent image to form a visible image using the toner described in any one of claims 1 to 4 or the developer described in claim 5, A transfer step of transferring the visible image onto a recording medium, A fixing step for fixing the transferred image onto the recording medium, An image forming method including [specific details omitted].

Images