JP7786243B2 - Toner, developer, toner storage unit, image forming apparatus, and image forming method - Google Patents

Description

The present invention relates to toner, developer, toner storage unit, image forming apparatus, and image forming method.

Traditionally, electrophotographic and electrostatic recording image forming devices form images by visualizing an electric or magnetic latent image with toner. For example, in electrophotography, an electrostatic latent image is formed on a photoreceptor, and then developed with toner to form a toner image. The toner image is then transferred to a recording medium such as paper, where it is heated, melted, and fixed.

In recent years, toners have been required to have smaller particle size and high-temperature offset resistance to improve the quality of output images, low-temperature fixability to save energy, and heat-resistant storage properties that can withstand the high temperatures and humidity experienced during storage and transportation after production. Since the power consumed during fixation accounts for a large portion of the power consumed in the image formation process, improving low-temperature fixability is particularly important.

Traditionally, toner produced by the kneading and pulverizing method has been used. However, the toner obtained by this conventional kneading and pulverizing method is difficult to reduce in particle size, has an irregular shape, and has a broad particle size distribution. It also requires high fixing temperatures, making it difficult to achieve energy savings. Furthermore, with the kneading and pulverizing method, the release agent (wax) breaks at the interface during pulverization, resulting in a large amount of release agent (wax) on the toner surface. While this provides a release effect during fixing, it also makes toner more susceptible to adhesion (filming) of the toner to the carrier, photoreceptor, and blade, resulting in unsatisfactory performance in the overall image formation process.

To overcome the problems associated with the kneading and pulverization method, a method for producing toner using a polymerization method has been proposed. Toner produced using a polymerization method is easy to reduce in particle size, has a sharper particle size distribution than toner produced using a pulverization method, and can also incorporate wax. Toner produced using this polymerization method is more spherical than pulverized toner, which can lead to issues with poor cleaning performance. Furthermore, in response to recent demands for energy conservation, further improvements in low-temperature fixability are required. Therefore, it is desirable to ensure that improvements in low-temperature fixability do not impair the toner's heat-resistant storage stability or hot offset resistance.

Furthermore, small particle size toners have been proposed with the aim of providing toners with excellent low-temperature fixability (see, for example, Patent Documents 1 to 8).

However, the above techniques do not satisfy the high level of low temperature fixability that has been demanded in recent years.
An object of the present invention is to provide a toner which has good low-temperature fixability, good cleaning properties and does not scatter.

The above problem is solved by the following configuration 1).
1) A toner containing at least a binder resin, a colorant, and an inorganic filler,
the toner has an Al atomic concentration % of 0.35 or more and 0.85 or less when measured by X-ray fluorescence elemental analysis (XRF);
where M1 is the atomic concentration % of Al in the toner measured by X-ray photoelectron spectroscopy (XPS), M2 is the atomic concentration % of Al measured by XRF, and Dv is the volume average particle size of the toner, M3 is the atomic concentration % of Al in particles classified into 6/5 Dv measured by XPS, and M4 is the atomic concentration % of Al in particles classified into 6/5 Dv measured by XRF, the relationship of 0.8<(M1/M2)/(M3/M4)<1.2 is satisfied,
The (M1/M2) ratio exceeds 1.4,
The toner , wherein the binder resin contains a crystalline polyester resin, and the amount of the crystalline polyester resin is 3 parts by mass or more and 20 parts by mass or less per 100 parts by mass of the toner .

The present invention provides a toner that combines good low-temperature fixability and cleanability, and does not scatter.

FIG. 1 is a schematic diagram showing an example of the image forming apparatus of the present invention. FIG. 2 is a schematic diagram showing another example of the image forming apparatus of the present invention. FIG. 3 is a schematic diagram showing another example of the image forming apparatus of the present invention. FIG. 4 is a partial enlarged view of FIG. 3 . FIG. 5 is a schematic diagram showing an example of a process cartridge.

Embodiments of the present invention are described in detail below.

(toner)
The toner of the present invention contains at least a binder resin, a colorant, and an inorganic filler, and is characterized in that the toner has an Al atomic concentration % of 0.35 or more and 0.85 or less when measured by X-ray fluorescence elemental analysis (XRF), and the relationship of 0.8<(M1/M2)/(M3/M4)<1.2 is satisfied, where M1 is the Al atomic concentration % of the toner when measured by X-ray photoelectron spectroscopy (XPS), M2 is the Al atomic concentration % of the toner when measured by XRF, and Dv is the volume average particle diameter of the toner. M3 is the Al atomic concentration % of the toner when measured by XPS of particles classified into 6/5 Dv, and M4 is the Al atomic concentration % of the toner when measured by XRF of particles classified into 6/5 Dv.

In this embodiment, the Al atomic concentration % measured by X-ray fluorescence elemental analysis (XRF) of the toner is an indicator of the amount of Al in the toner bulk, and the Al atomic concentration measured by X-ray photoelectron spectroscopy (XPS) of the toner is an indicator of the Al concentration on the toner surface.

Previous patent documents have described toners that have excellent low-temperature fixability, cleanability, and transfer efficiency, and that leave little residual toner behind after transfer. However, these have not been sufficient to meet the recent demand for energy conservation, and further improvements in low-temperature fixability are needed.

Toner incorporating inorganic substances has improved charging properties and shape controllability, which is advantageous in terms of transfer and cleaning. However, inorganic substances have high melting points, which reduces the low-temperature fixability of the toner as a whole. Furthermore, if inorganic substances are unevenly distributed, when the toner and carrier are mixed prior to transfer, uneven charging occurs when newly replenished toner is mixed, which can cause toner scattering.

The inventors have conducted extensive research into toners incorporating these inorganic substances and have discovered that uniformly dispersing specific metal elements present near the toner surface, increasing the toner's hardness and stress resistance, is effective in preventing scattering. They have also discovered that if the added metal elements can be appropriately positioned on the toner surface, the occurrence of uneven charging can be suppressed with a minimum amount of metal element, making it possible to create a toner that has improved low-temperature fixation, good cleaning properties, and is less likely to scatter.

The toner of the present invention having the above-described configuration has good low-temperature fixability and cleanability, and can reduce scattering.

This invention limits the Al (aluminum) content in toner to a specific range and optimizes the amount of Al (aluminum) unevenly distributed on the toner surface depending on the particle size distribution. Specifically, by setting the Al content in the entire toner within a specific range, and letting M1 be the atomic concentration (%) of Al in the toner measured by X-ray photoelectron spectroscopy (XPS), M2 be the atomic concentration (%) of Al measured by XRF, and Dv be the volume-average particle size of the toner, M3 be the atomic concentration (%) of Al in toner particles classified into 6/5 Dv measured by XPS, and M4 be the atomic concentration (%) of Al in toner particles classified into 6/5 Dv measured by XRF, satisfying the relationship 0.8 < (M1/M2) / (M3/M4) < 1.2 results in high uniformity between toner particles, a homogenous surface, and idealized inorganic material arrangement on the outermost surface, thereby suppressing toner scattering.

In addition, by optimizing the placement of inorganic materials, improved cleaning performance can be achieved with a minimum amount of inorganic material, and since there is no need to add more inorganic material than necessary, the low-temperature fixability effect can be improved. As a result, even if the toner incorporating Al (aluminum) has a certain degree of particle size distribution, the toner as a whole will have a good charge distribution, and will be able to combine good cleaning performance with low-temperature fixability.

This will be explained in detail below.
If the toner has low homogeneity, the inorganic material will be unevenly distributed, and more inorganic material than necessary will be required to achieve the effect of introducing the inorganic material, resulting in poor low-temperature fixability. Furthermore, when the toner and carrier are mixed, uneven charge levels occur, broadening the charge distribution and worsening toner scattering. Charge level differences are likely to occur between large-diameter particles classified into 6/5 Dv, adversely affecting image formation.

However, toner with too little inorganic material will have a spherical shape, which will result in poor cleaning properties, and will be unable to ensure sufficient charging properties, which will have a negative impact on image formation. For this reason, in the present invention, the Al atomic concentration (%) of the toner measured by X-ray fluorescence elemental analysis (XRF) must be 0.35 or more and 0.85 or less, preferably 0.4 or more and 0.8 or less, and more preferably 0.4 or more and 0.6 or less.

If the Al atomic concentration % measured by X-ray fluorescence elemental analysis (XRF) is less than 0.35, the shape will become closer to a perfect sphere, which will affect cleaning performance and also affect the amount of charge. If the Al atomic concentration % measured by X-ray fluorescence elemental analysis (XRF) is greater than 0.85, the toner's low-temperature fixability will be impaired.

Therefore, in the present invention, when the atomic concentration % of Al in a toner measured by X-ray photoelectron spectroscopy (XPS) is defined as M1, the atomic concentration % of Al measured by XRF is defined as M2, and the volume average particle size of the toner is defined as Dv, the atomic concentration % of Al when particles of the toner classified into 6/5 Dv are measured by XPS is defined as M3, and the atomic concentration % of Al when particles of the toner classified into 6/5 Dv are measured by XRF is defined as M4, by satisfying the relationship 0.8<(M1/M2)/(M3/M4)<1.2, it is possible to produce a toner that has a good charge distribution, is resistant to scattering, and has excellent low-temperature fixability.
The above (M1/M2)/(M3/M4) can be said to mean the ratio of the surface and bulk composition ratios between particles of different particle sizes.

Furthermore, in the present invention, it is more preferable for the (M1/M2)/(M3/M4) ratio to satisfy the relationship 0.9<(M1/M2)/(M3/M4)<1.1, as this further improves the effects of the present invention.

In addition, in the present invention, because a higher amount of Al element on the surface improves charging properties and reduces scattering, it is preferable that the (M1/M2) ratio be greater than 1.4, and it is even more preferable that the (M1/M2) ratio be greater than 1.4 and not greater than 2.1.

<X-ray fluorescence elemental analysis (XRF)>
The amount of Al (aluminum) contained in the toner can be measured by X-ray fluorescence elemental analysis (XRF), for example, as follows. To prepare a calibration curve, a toner containing a predetermined amount of layered inorganic mineral as an inorganic filler is prepared in advance. The procedure for preparing the sample is as follows.
3.75 g of a toner sample was dispersed in 50 mL of a 0.5% by weight polyoxyalkylene alkyl ether dispersion in a 110 mL vial. The toner dispersion was irradiated with ultrasonic waves for a certain period of time using an ultrasonic homogenizer (product name: homogenizer, model VCX750, CV33, SONICS & MATERIALS, Inc.). The ultrasonic wave was applied at a frequency of 20 Hz and an output of 40 W for 100 seconds. The amount of applied energy was calculated from the product of the output and the irradiation time. The toner dispersion was cooled as needed to prevent its temperature from rising above 40°C. The resulting dispersion was suction-filtered using filter paper (product name: Qualitative Filter Paper (No. 2, 110 mm), manufactured by Advantec Toyo Co., Ltd.), washed twice with ion-exchange water, filtered, and the free inorganic particles were removed. The toner was then dried.
After drying, 3 g of the obtained toner was molded into pellets having a diameter of 3 mm and a thickness of 2 mm using an automatic pressure molding machine (T-BRB-32, manufactured by Maekawa) under a load of 6.0 t and a pressing time of 60 seconds (manufacturer and conditions). The amount of Al (aluminum) in the toner was measured by quantitative analysis using a fluorescent X-ray analyzer (ZSX-100e, manufactured by Rigaku Denki).
Hereinafter, a case where a layered inorganic mineral is used as an inorganic filler will be described as a representative example, but the present invention is not limited to the following embodiment.

<X-ray photoelectron spectroscopy (XPS)>
The amount of Al (aluminum) present in the vicinity of the toner surface can be measured by X-ray photoelectron spectroscopy (XPS), for example, as follows: XPS usually makes it possible to detect the atomic concentration within a range of about several tens of nanometers from the particle surface.
Equipment used: PHI 1600S model X-ray photoelectron spectrometer. Conditions of use: X-ray source MgKα (100 W).
Analysis area: 0.8 x 2.0mm
The toner is placed on a carbon sheet on a sample holder and measured. The toner used at this time is treated as follows beforehand.
3.75 g of a toner sample was dispersed in 50 mL of a 0.5% by weight polyoxyalkylene alkyl ether dispersion in a 110 mL vial. The toner dispersion was irradiated with ultrasonic waves for a certain period of time using an ultrasonic homogenizer (product name: homogenizer, model VCX750, CV33, SONICS & MATERIALS, Inc.). The ultrasonic wave was applied at a frequency of 20 Hz and an output of 40 W for 100 seconds. The amount of applied energy was calculated from the product of the output and the irradiation time. The toner dispersion was cooled as needed to prevent its temperature from rising above 40°C. The resulting dispersion was suction-filtered using filter paper (product name: Qualitative Filter Paper (No. 2, 110 mm), manufactured by Advantec Toyo Co., Ltd.), washed twice with ion-exchange water, filtered, and the free inorganic particles were removed. The toner was then dried.
The surface atomic concentration is estimated by calculation using the relative sensitivity factor provided by PHI from the peak intensity of each measured atomic concentration. In this measurement, since the layered inorganic mineral contains aluminum (Al), it is possible to estimate the atomic concentration (%) of Al from among the detected elements.

<Volume average particle size (Dv)>
The volume average particle size (Dv) was measured using a particle size analyzer (Multisizer III, manufactured by Beckman Coulter) with an aperture diameter of 100 μm, and analyzed using analysis software (Beckman Coulter Multisizer 3 Version 3.51). Specifically, 0.5 mL of a 10% by weight surfactant (alkylbenzene sulfonate Neogen SC-A; manufactured by Dai-ichi Kogyo Seiyaku) was added to a 100 mL glass beaker, 0.5 g of each toner was added, and the mixture was stirred with a microspatula. 80 mL of ion-exchanged water was then added. The resulting dispersion was dispersed for 10 minutes using an ultrasonic disperser (W-113MK-II, manufactured by Honda Electronics Co., Ltd.). The dispersion was measured using the Multisizer III and an Isoton III (manufactured by Beckman Coulter) as the measurement solution. Note that particles obtained by classifying the toner into 6/5 Dv can be obtained by conventional methods.

To produce a toner that satisfies the above-mentioned relationship, the following adjustment methods can be used.
A binder resin, a colorant, a layered inorganic mineral, and optionally a release agent are dispersed in an organic solvent. The better the dispersibility, the less likely the materials are to be unevenly distributed, and the more homogeneous the toner becomes. A crosslinker/extender containing a tertiary amine is added to obtain an oil-based dispersion. This oil-based dispersion is then dispersed in an aqueous medium containing resin particles to obtain an emulsified dispersion, and the organic solvent is removed from the emulsified dispersion to obtain a toner.
In the manufacturing method of the oil-based dispersion, the amount of Al present on the particle surface can be adjusted by appropriate dispersion. If the dispersion is weak, the layered inorganic mineral cannot be sufficiently dispersed, and the layered inorganic mineral will be unevenly distributed in clumps in the toner, causing uneven charging properties and, since it cannot fully perform its function, the required amount of layered inorganic mineral will be greater than necessary, resulting in poor fixability.

On the other hand, if dispersion is too strong, such as by crushing primary particles, the raw materials will be dispersed more than necessary, resulting in an over-dispersed state. In an over-dispersed state, the interfaces between the raw material particles are highly chemically active, causing a significant increase in viscosity and re-aggregation of layered inorganic minerals, which can affect quality such as a significant increase in charge and image blurring due to toner deformation.

In the toner manufacturing method, the amount of Al (aluminum) present on the toner surface can be adjusted by adjusting the amount of energy applied when dispersing the toner in the oil-based dispersion. The toner manufacturing method of the present invention is described in detail below.

Next, we will explain the binder resin, release agent, colorant, etc. contained in the toner base particles in this embodiment. Furthermore, the toner in this embodiment may also contain external additives in addition to the toner base particles.

<Binder resin>
The binder resin preferably contains a polyester resin, and examples of the polyester resin include a crystalline polyester resin and an amorphous polyester resin.

<Crystalline polyester resin>
The crystalline polyester resin (hereinafter, sometimes referred to as "crystalline polyester resin C") has high crystallinity and therefore exhibits heat melting characteristics that show a sudden change in viscosity near the fixing start temperature.

By using crystalline polyester resin C having such properties together with an amorphous polyester resin, a toner having both good heat-resistant storage stability and low-temperature fixability can be obtained. For example, by using both, the heat-resistant storage stability is good due to the crystallinity up to just before the melting initiation temperature, and at the melting initiation temperature, a sudden viscosity drop (sharp melt property) occurs due to the melting of crystalline polyester resin C, which is then compatible with amorphous polyester resin B described later, and both rapidly drop in viscosity, allowing for good fixation.
Also, good results are shown for the release width (the difference between the minimum fixing temperature and the temperature at which high-temperature offset occurs).

The crystalline polyester resin C is obtained using a polyhydric alcohol and a polycarboxylic acid or its derivative, such as a polycarboxylic acid, a polycarboxylic acid anhydride, or a polycarboxylic acid ester.

In the present invention, crystalline polyester resin C refers to a resin obtained using a polyhydric alcohol and a polycarboxylic acid, such as a polycarboxylic acid, a polycarboxylic acid anhydride, or a polycarboxylic acid ester, or a derivative thereof, as described above. Modified polyester resins, such as the prepolymers described below, and resins obtained by subjecting such prepolymers to a crosslinking and/or elongation reaction, do not fall under the category of crystalline polyester resin C.

-Polyhydric alcohol-
The polyhydric alcohol is not particularly limited and can be appropriately selected depending on the purpose. Examples thereof include diols and trihydric or higher alcohols.
Examples of the diol include saturated aliphatic diols. Examples of the saturated aliphatic diol include linear saturated aliphatic diols and branched saturated aliphatic diols. Among these, linear saturated aliphatic diols are preferred, and linear saturated aliphatic diols having 2 to 12 carbon atoms are more preferred. If the saturated aliphatic diol is branched, the crystallinity of the crystalline polyester resin C may decrease, resulting in a lower melting point. Furthermore, if the carbon number of the saturated aliphatic diol exceeds 12, it becomes difficult to obtain a practical material. It is more preferred that the carbon number be 12 or less.

Examples of the saturated aliphatic diol include ethylene glycol, 1,3-propanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 1,7-heptanediol, 1,8-octanediol, 1,9-nonanediol, 1,10-decanediol, 1,11-undecanediol, 1,12-dodecanediol, 1,13-tridecanediol, 1,14-tetradecanediol, 1,18-octadecanediol, and 1,14-eicosanedecanediol. Among these, ethylene glycol, 1,4-butanediol, 1,6-hexanediol, 1,8-octanediol, 1,10-decanediol, and 1,12-dodecanediol are preferred because they result in high crystallinity and excellent sharp melt properties for the crystalline polyester resin C.

Examples of the trivalent or higher alcohol include glycerin, trimethylolethane, trimethylolpropane, and pentaerythritol.
These may be used alone or in combination of two or more.

- Polycarboxylic acid -
The polycarboxylic acid is not particularly limited and can be appropriately selected depending on the purpose. Examples thereof include dicarboxylic acids and tricarboxylic or higher carboxylic acids.

Examples of the dicarboxylic acid include saturated aliphatic dicarboxylic acids such as oxalic acid, succinic acid, glutaric acid, adipic acid, suberic acid, azelaic acid, sebacic acid, 1,9-nonanedicarboxylic acid, 1,10-decanedicarboxylic acid, 1,12-dodecanedicarboxylic acid, 1,14-tetradecanedicarboxylic acid, and 1,18-octadecanedicarboxylic acid; and aromatic dicarboxylic acids such as dibasic acids such as phthalic acid, isophthalic acid, terephthalic acid, naphthalene-2,6-dicarboxylic acid, malonic acid, and mesaconic acid; as well as anhydrides and lower (1 to 3 carbon atoms) alkyl esters of these.

Examples of the trivalent or higher carboxylic acid include 1,2,4-benzenetricarboxylic acid, 1,2,5-benzenetricarboxylic acid, 1,2,4-naphthalenetricarboxylic acid, etc., as well as their anhydrides and lower (1 to 3 carbon atoms) alkyl esters.

The polycarboxylic acid may include a dicarboxylic acid having a sulfonic acid group in addition to the saturated aliphatic dicarboxylic acid and aromatic dicarboxylic acid, and may further include a dicarboxylic acid having a double bond in addition to the saturated aliphatic dicarboxylic acid and aromatic dicarboxylic acid.
These may be used alone or in combination of two or more.

The crystalline polyester resin C is preferably composed of a linear saturated aliphatic dicarboxylic acid having from 4 to 12 carbon atoms and a linear saturated aliphatic diol having from 2 to 12 carbon atoms. That is, the crystalline polyester resin C preferably has structural units derived from a saturated aliphatic dicarboxylic acid having from 4 to 12 carbon atoms and structural units derived from a saturated aliphatic diol having from 2 to 12 carbon atoms. This is preferable in that it has high crystallinity and excellent sharp melt properties, allowing it to exhibit excellent low-temperature fixability.

The melting point of the crystalline polyester resin C is not particularly limited and can be selected appropriately depending on the purpose, but is preferably 60°C or higher and 80°C or lower. A melting point of 60°C or higher can prevent the crystalline polyester resin C from melting at low temperatures, which would otherwise cause a decrease in the heat-resistant storage stability of the toner. A melting point of 80°C or lower can improve the melting of the crystalline polyester resin C due to heating during fixing, preventing a decrease in low-temperature fixability.

The molecular weight of the crystalline polyester resin C is not particularly limited and can be appropriately selected depending on the purpose. From the viewpoint that a resin having a sharp molecular weight distribution and a low molecular weight has excellent low-temperature fixability, and that a large amount of low-molecular-weight components reduces heat-resistant storage stability, it is preferable that the ortho-dichlorobenzene-soluble portion of the crystalline polyester resin C has a weight-average molecular weight (Mw) of 3,000 to 30,000, a number-average molecular weight (Mn) of 1,000 to 10,000, and an Mw/Mn of 1.0 to 10, as measured by GPC.
It is further preferred that the weight average molecular weight (Mw) is 5,000 to 15,000, the number average molecular weight (Mn) is 2,000 to 10,000, and the Mw/Mn is 1.0 to 5.0.

There are no particular restrictions on the acid value of the crystalline polyester resin C, and it can be selected appropriately depending on the purpose. From the viewpoint of affinity between paper and resin, in order to achieve the desired low-temperature fixability, an acid value of 5 mgKOH/g or more is preferred, and 10 mgKOH/g or more is more preferred. On the other hand, in order to improve high-temperature offset resistance, an acid value of 45 mgKOH/g or less is preferred.

The hydroxyl value of the crystalline polyester resin C is not particularly limited and can be selected appropriately depending on the purpose. To achieve the desired low-temperature fixability and good charging characteristics, a hydroxyl value of 0 mgKOH/g to 50 mgKOH/g is preferred, and a value of 5 mgKOH/g to 50 mgKOH/g is more preferred.

The molecular structure of the crystalline polyester resin C can be confirmed by NMR measurement using a solution or a solid, as well as by X-ray diffraction, GC/MS, LC/MS, IR measurement, etc. A simple method is to detect, as the crystalline polyester resin C, a resin having absorption at 965 ^cm ±10 ^cm or 990 ^cm ±10 ^cm in an infrared absorption spectrum due to olefin δCH (out-of-plane bending vibration).

The content of the crystalline polyester resin C is not particularly limited and can be selected appropriately depending on the purpose, but is preferably 3 to 20 parts by weight, and more preferably 5 to 15 parts by weight, per 100 parts by weight of the toner. When the content is 3 parts by weight or more, the crystalline polyester resin C provides a sharp melt, resulting in good low-temperature fixability. Furthermore, when the content is 20 parts by weight or less, good heat-resistant storage stability is achieved, resulting in high-quality images.

<Amorphous polyester resin>
The amorphous polyester resin is not particularly limited and can be appropriately selected depending on the purpose, but it is preferable that the amorphous polyester resin contains an amorphous polyester resin A and an amorphous polyester resin B described below.

-Amorphous polyester resin A-
The amorphous polyester resin A is not particularly limited and can be appropriately selected depending on the purpose, but the glass transition temperature (Tg) thereof is preferably −60° C. or higher and 20° C. or lower, and more preferably −40° C. or higher and 20° C. or lower.

The amorphous polyester resin A is not particularly limited and can be selected appropriately depending on the purpose, but it is preferably obtained by reacting a non-linear reactive precursor with a curing agent.

Furthermore, it is preferable that amorphous polyester resin A contains at least one of a urethane bond and a urea bond, as this provides better adhesion to recording media such as paper. By containing either a urethane bond or a urea bond in amorphous polyester resin A, the urethane bond or urea bond behaves like a pseudo-crosslinking point, strengthening the rubber-like properties of amorphous polyester resin A and providing the toner with better heat-resistant storage stability and high-temperature offset resistance.

--Nonlinear reactive precursors--
The non-linear reactive precursor is not particularly limited as long as it is a polyester resin (hereinafter, sometimes referred to as a "prepolymer") having a group capable of reacting with the curing agent, and can be appropriately selected depending on the purpose.
Examples of the group in the prepolymer that can react with the curing agent include a group that can react with an active hydrogen group. Examples of the group that can react with the active hydrogen group include an isocyanate group, an epoxy group, a carboxylic acid, and an acid chloride group. Among these, an isocyanate group is preferred because it can introduce a urethane bond or a urea bond into the amorphous polyester resin.

The prepolymer is preferably non-linear, which means that it has a branched structure imparted by at least one of a trivalent or higher alcohol and a trivalent or higher carboxylic acid.
The prepolymer is preferably a polyester resin containing an isocyanate group.

---Polyester resin containing isocyanate groups---
The polyester resin containing an isocyanate group is not particularly limited and can be appropriately selected depending on the purpose, and examples thereof include a reaction product of a polyester resin having an active hydrogen group with a polyisocyanate. The polyester resin having an active hydrogen group can be obtained, for example, by polycondensation of a diol, a dicarboxylic acid, and at least one of a trivalent or higher alcohol and a trivalent or higher carboxylic acid. The trivalent or higher alcohol and the trivalent or higher carboxylic acid impart a branched structure to the polyester resin containing an isocyanate group.

---Diol---
The diol is not particularly limited and can be appropriately selected depending on the purpose. Examples thereof include aliphatic diols such as ethylene glycol, 1,2-propylene glycol, 1,3-propylene glycol, 1,4-butanediol, 3-methyl-1,5-pentanediol, 1,6-hexanediol, 1,8-octanediol, 1,10-decanediol, and 1,12-dodecanediol; diethylene glycol, triethylene glycol, dipropylene glycol, polyethylene glycol, polypropylene glycol, and polytetramethylene Examples of the diol include diols having an oxyalkylene group such as glycol; alicyclic diols such as 1,4-cyclohexanedimethanol and hydrogenated bisphenol A; alicyclic diols to which alkylene oxides such as ethylene oxide, propylene oxide, and butylene oxide have been added; bisphenols such as bisphenol A, bisphenol F, and bisphenol S; and alkylene oxide adducts of bisphenols, such as bisphenols to which alkylene oxides such as ethylene oxide, propylene oxide, and butylene oxide have been added. Among these, aliphatic diols having from 4 to 12 carbon atoms are preferred. These diols may be used alone or in combination of two or more.

---Dicarboxylic acid---
The dicarboxylic acid is not particularly limited and can be appropriately selected depending on the purpose, and examples thereof include aliphatic dicarboxylic acids, aromatic dicarboxylic acids, etc. Furthermore, anhydrides, lower (1 to 3 carbon atoms) alkyl esters, or halides of these may also be used.

The aliphatic dicarboxylic acid is not particularly limited and can be selected appropriately depending on the purpose. Examples include succinic acid, adipic acid, sebacic acid, dodecanedioic acid, maleic acid, and fumaric acid.

The aromatic dicarboxylic acid is not particularly limited and can be appropriately selected depending on the purpose, but is preferably an aromatic dicarboxylic acid having 8 to 20 carbon atoms. The aromatic dicarboxylic acid having 8 to 20 carbon atoms is not particularly limited and can be appropriately selected depending on the purpose, and examples thereof include phthalic acid, isophthalic acid, terephthalic acid, and naphthalenedicarboxylic acid.
Among these, aliphatic dicarboxylic acids having 4 to 12 carbon atoms are preferred.
These dicarboxylic acids may be used alone or in combination of two or more.

---Trihydric or higher alcohols---
The trihydric or higher alcohol is not particularly limited and can be appropriately selected depending on the purpose. Examples thereof include trihydric or higher aliphatic alcohols, trihydric or higher polyphenols, and alkylene oxide adducts of trihydric or higher polyphenols.

Examples of the trivalent or higher aliphatic alcohol include glycerin, trimethylolethane, trimethylolpropane, pentaerythritol, and sorbitol.
Examples of the trivalent or higher polyphenols include trisphenol PA, phenol novolac, and cresol novolac.
Examples of the alkylene oxide adducts of trivalent or higher polyphenols include those obtained by adding alkylene oxides such as ethylene oxide, propylene oxide, and butylene oxide to trivalent or higher polyphenols.

The amorphous polyester resin A preferably contains a trivalent or higher aliphatic alcohol as a constituent component. By including a trivalent or higher aliphatic alcohol as a constituent component, the amorphous polyester resin A has a branched structure in the molecular skeleton, and the molecular chains form a three-dimensional network structure. This gives the resin rubber-like properties of being deformable at low temperatures but not flowing. This enables the toner to maintain its heat-resistant storage stability and high-temperature offset resistance.

The amorphous polyester resin A can also use trivalent or higher carboxylic acids or epoxy as crosslinking components, but in the case of carboxylic acids, they are often aromatic compounds and the ester bond density at the crosslinked portions is high, which can prevent the gloss of the fixed image created by heat-fixing the toner from being fully developed. When using a crosslinking agent such as epoxy, the crosslinking reaction must be carried out after the polyester is polymerized, making it difficult to control the distance between crosslinking points and preventing the desired viscoelasticity from being achieved. Furthermore, the crosslinked portion is likely to react with the oligomer during polyester production, resulting in areas with high crosslink density, which can cause unevenness in the fixed image and poor gloss and image density.

---Trivalent or higher carboxylic acid---
The trivalent or higher carboxylic acid is not particularly limited and can be appropriately selected depending on the purpose, and examples thereof include trivalent or higher aromatic carboxylic acids. Furthermore, anhydrides, lower (1 to 3 carbon atoms) alkyl esters, or halides of these may also be used.

The trivalent or higher aromatic carboxylic acid is preferably a trivalent or higher aromatic carboxylic acid having 9 to 20 carbon atoms. Examples of the trivalent or higher aromatic carboxylic acid having 9 to 20 carbon atoms include trimellitic acid and pyromellitic acid.

---Polyisocyanate---
The polyisocyanate is not particularly limited and can be appropriately selected depending on the purpose. Examples thereof include diisocyanates and tri- or higher valent isocyanates.

Examples of the diisocyanate include aliphatic diisocyanates, alicyclic diisocyanates, aromatic diisocyanates, araliphatic diisocyanates, isocyanurates, and compounds obtained by blocking these with phenol derivatives, oximes, caprolactam, etc.

The aliphatic diisocyanate is not particularly limited and can be appropriately selected depending on the purpose. Examples include tetramethylene diisocyanate, hexamethylene diisocyanate, methyl 2,6-diisocyanatocaproate, octamethylene diisocyanate, decamethylene diisocyanate, dodecamethylene diisocyanate, tetradecamethylene diisocyanate, trimethylhexane diisocyanate, and tetramethylhexane diisocyanate.

The alicyclic diisocyanate is not particularly limited and can be selected appropriately depending on the purpose. Examples include isophorone diisocyanate and cyclohexylmethane diisocyanate.

The aromatic diisocyanate is not particularly limited and can be selected appropriately depending on the purpose. Examples include tolylene diisocyanate, diisocyanatodiphenylmethane, 1,5-naphthylene diisocyanate, 4,4'-diisocyanatodiphenyl, 4,4'-diisocyanato-3,3'-dimethyldiphenyl, 4,4'-diisocyanato-3-methyldiphenylmethane, and 4,4'-diisocyanato-diphenyl ether.

The aromatic aliphatic diisocyanate is not particularly limited and can be selected appropriately depending on the purpose. Examples include α,α,α',α'-tetramethylxylylene diisocyanate.

The isocyanurates are not particularly limited and can be selected appropriately depending on the purpose. Examples include tris(isocyanatoalkyl)isocyanurate and tris(isocyanatocycloalkyl)isocyanurate. These polyisocyanates may be used alone or in combination of two or more.

--hardening agent--
The curing agent is not particularly limited as long as it can react with the non-linear reactive precursor to produce the amorphous polyester resin A, and can be appropriately selected depending on the purpose. For example, an active hydrogen group-containing compound can be used.

--- Active hydrogen group-containing compound ---
The active hydrogen group in the active hydrogen group-containing compound is not particularly limited and can be appropriately selected depending on the purpose, and examples thereof include a hydroxyl group (alcoholic hydroxyl group and phenolic hydroxyl group), an amino group, a carboxyl group, a mercapto group, etc. These may be used alone or in combination of two or more.
The active hydrogen group-containing compound is not particularly limited and can be appropriately selected depending on the purpose, but amines are preferred because they are capable of forming a urea bond.

The amines are not particularly limited and can be appropriately selected depending on the purpose, and examples thereof include diamines, trivalent or higher amines, amino alcohols, amino mercaptans, amino acids, and compounds in which the amino group of these is blocked. These may be used alone or in combination of two or more.
Among these, diamines and mixtures of diamines with small amounts of trivalent or higher amines are preferred.

The diamine is not particularly limited and can be selected appropriately depending on the purpose. Examples include aromatic diamines, alicyclic diamines, and aliphatic diamines. The aromatic diamine is not particularly limited and can be selected appropriately depending on the purpose. Examples include phenylenediamine, diethyltoluenediamine, and 4,4'-diaminodiphenylmethane.

The alicyclic diamine is not particularly limited and can be selected appropriately depending on the purpose, and examples thereof include 4,4'-diamino-3,3'-dimethyldicyclohexylmethane, diaminocyclohexane, and isophoronediamine. The aliphatic diamine is not particularly limited and can be selected appropriately depending on the purpose, and examples thereof include ethylenediamine, tetramethylenediamine, and hexamethylenediamine.

The trivalent or higher amine is not particularly limited and can be appropriately selected depending on the purpose. Examples thereof include diethylenetriamine and triethylenetetramine.
The amino alcohol is not particularly limited and can be appropriately selected depending on the purpose. Examples thereof include ethanolamine and hydroxyethylaniline.
The amino mercaptan is not particularly limited and can be appropriately selected depending on the purpose. Examples thereof include aminoethyl mercaptan and aminopropyl mercaptan.
The amino acid is not particularly limited and can be appropriately selected depending on the purpose. Examples thereof include aminopropionic acid and aminocaproic acid.
The compound in which the amino group is blocked is not particularly limited and can be appropriately selected depending on the purpose. Examples thereof include ketimine compounds and oxazoline compounds obtained by blocking the amino group with ketones such as acetone, methyl ethyl ketone, and methyl isobutyl ketone.

In order to lower the Tg of the amorphous polyester resin A and make it easier to impart deformation properties at low temperatures, the amorphous polyester resin A preferably contains a diol component as a constituent component, and the diol component preferably contains 50% by mass or more of an aliphatic diol having from 4 to 12 carbon atoms.

Furthermore, the amorphous polyester resin A preferably contains 50% by mass or more of an aliphatic diol having 4 to 12 carbon atoms in total alcohol components. In this case, the Tg of the amorphous polyester resin A can be lowered, making it easier to impart the property of deformation at low temperatures.

The amorphous polyester resin A preferably contains a dicarboxylic acid component as a constituent, and the dicarboxylic acid component preferably contains 50% by mass or more of an aliphatic dicarboxylic acid having 4 to 12 carbon atoms. In this case, the Tg of the amorphous polyester resin A can be lowered, making it easier to impart the property of deformation at low temperatures.

The weight-average molecular weight of the amorphous polyester resin A is not particularly limited and can be selected appropriately depending on the purpose. However, as measured by GPC (gel permeation chromatography), it is preferably 10,000 or more and 1,000,000 or less, more preferably 10,000 or more and 300,000 or less, and particularly preferably 10,000 or more and 200,000 or less. When the weight-average molecular weight is 10,000 or more, the toner is prevented from flowing at low temperatures, improving its heat-resistant storage stability. It also prevents a decrease in viscosity during melting, preventing a deterioration in high-temperature offset properties.

The molecular structure of the amorphous polyester resin A can be confirmed by NMR measurement using a solution or a solid, as well as by X-ray diffraction, GC/MS, LC/MS, IR measurement, etc. A simple method is to detect an amorphous polyester resin by an infrared absorption spectrum that does not exhibit absorption at 965±10 cm ⁻¹ and 990±10 cm ⁻¹ due to olefin δCH (out-of-plane bending vibration).

The content of the amorphous polyester resin A is not particularly limited and can be selected appropriately depending on the purpose, but is preferably 5 to 25 parts by weight, and more preferably 10 to 20 parts by weight, per 100 parts by weight of the toner. A content of 5 parts by weight or more can prevent deterioration of low-temperature fixability and high-temperature offset resistance. A content of 25 parts by weight or less can prevent deterioration of heat-resistant storage stability and a decrease in the gloss of the image obtained after fixing. A content within the above more preferred range is advantageous in that all of low-temperature fixability, high-temperature offset resistance, and heat-resistant storage stability are excellent.

-Amorphous polyester resin B-
The amorphous polyester resin B is preferably a linear polyester resin, and more preferably an unmodified polyester resin.
The unmodified polyester resin is a polyester resin obtained using a polyhydric alcohol and a polycarboxylic acid or a derivative thereof, such as a polycarboxylic acid, a polycarboxylic acid anhydride, or a polycarboxylic acid ester, and is not modified with an isocyanate compound or the like.
The amorphous polyester resin B preferably does not contain a urethane bond or a urea bond.

The amorphous polyester resin B preferably contains a dicarboxylic acid component as a constituent, and the dicarboxylic acid component preferably contains 50 mol % or more of terephthalic acid. This is advantageous in terms of heat-resistant storage stability.

Examples of the polyhydric alcohol include diols.
Examples of the diol include alkylene (having 2 to 3 carbon atoms) oxide (average number of moles added: 1 to 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; hydrogenated bisphenol A, and alkylene (having 2 to 3 carbon atoms) oxide (average number of moles added: 1 to 10) adducts of hydrogenated bisphenol A.
These may be used alone or in combination of two or more.

Examples of the polycarboxylic acid include dicarboxylic acids.
Examples of the dicarboxylic acid include adipic acid, phthalic acid, isophthalic acid, terephthalic acid, fumaric acid, maleic acid; and succinic acids substituted with an alkyl group having 1 to 20 carbon atoms or an alkenyl group having 2 to 20 carbon atoms, such as dodecenylsuccinic acid and octylsuccinic acid.
These may be used alone or in combination of two or more.

Furthermore, for the purpose of adjusting the acid value and hydroxyl value, the amorphous polyester resin B may contain at least one of a trivalent or higher carboxylic acid and a trivalent or higher alcohol at the end of the resin chain.
Examples of the trivalent or higher carboxylic acid include trimellitic acid, pyromellitic acid, and acid anhydrides thereof.
Examples of the trivalent or higher alcohol include glycerin, pentaerythritol, and trimethylolpropane.

The molecular weight of the amorphous polyester resin B is not particularly limited and can be selected appropriately depending on the purpose. As measured by GPC (gel permeation chromatography), the weight average molecular weight (Mw) is preferably 3,000 to 10,000. The number average molecular weight (Mn) is preferably 1,000 to 4,000. The Mw/Mn ratio is preferably 1.0 to 4.0.

When the molecular weight is above the lower limit, it is possible to prevent the toner's heat-resistant storage stability and durability against stress such as stirring in a developing machine from decreasing. When the molecular weight is below the upper limit, it is possible to prevent the toner's viscoelasticity from increasing when melted, and to prevent a decrease in low-temperature fixability.

The weight average molecular weight (Mw) is more preferably 4,000 to 7,000. The number average molecular weight (Mn) is more preferably 1,500 to 3,000. The Mw/Mn ratio is more preferably 1.0 to 3.5.

The acid value of the amorphous polyester resin B is not particularly limited and can be selected appropriately depending on the purpose. It is preferably 1 mgKOH/g to 50 mgKOH/g, and more preferably 5 mgKOH/g to 30 mgKOH/g. An acid value of 1 mgKOH/g or more makes the toner more likely to be negatively charged, and further improves the affinity between the paper and the toner when fixed to paper, thereby improving low-temperature fixability. An acid value of 50 mgKOH/g or less can prevent a decrease in charging stability, particularly charging stability against environmental fluctuations.

The hydroxyl value of the amorphous polyester resin B is not particularly limited and can be selected appropriately depending on the purpose, but it is preferably 5 mg KOH/g or more.

The glass transition temperature (Tg) of the amorphous polyester resin B is preferably 40°C or higher and 80°C or lower, and more preferably 50°C or higher and 70°C or lower. A glass transition temperature of 40°C or higher ensures sufficient heat-resistant storage stability of the toner and durability against stresses such as agitation in a developing machine, and also provides good filming resistance. A glass transition temperature of 80°C or lower ensures sufficient deformation due to heat and pressure during toner fixing, resulting in good low-temperature fixing properties.

The molecular structure of the amorphous polyester resin B can be confirmed by NMR measurement using a solution or a solid, as well as by X-ray diffraction, GC/MS, LC/MS, IR measurement, etc. A simple method is to detect an amorphous polyester resin by an infrared absorption spectrum that does not exhibit absorption at 965±10 cm ⁻¹ and 990±10 cm ⁻¹ due to olefin δCH (out-of-plane bending vibration).

The content of the amorphous polyester resin B is not particularly limited and can be selected appropriately depending on the purpose, but is preferably 50 to 90 parts by weight, and more preferably 60 to 80 parts by weight, per 100 parts by weight of the toner. A content of 50 parts by weight or more can prevent deterioration of the dispersibility of the pigment and release agent in the toner, and can prevent image fogging and distortion. A content of 90 parts by weight or less can prevent the contents of the crystalline polyester resin C and amorphous polyester resin A from decreasing, and can prevent a decrease in low-temperature fixability. A content within the above more preferred range is advantageous in that both high image quality and low-temperature fixability are excellent.

To further improve low-temperature fixability, it is preferable to use the amorphous polyester resin A and the crystalline polyester resin C in combination. To achieve both low-temperature fixability and high-temperature, high-humidity storage stability, it is preferable that the amorphous polyester resin A have an extremely low glass transition temperature. Because the glass transition temperature is extremely low, the resin has the property of deforming at low temperatures, deforming in response to heat and pressure during fixation, and has the property of easily adhering to recording media such as paper at lower temperatures. Furthermore, in one embodiment of the amorphous polyester resin A, the reactive precursor is nonlinear, so the molecular skeleton has a branched structure and the molecular chains form a three-dimensional network structure. This gives the resin rubber-like properties of deforming at low temperatures but not flowing. This enables the toner to maintain its heat-resistant storage stability and high-temperature offset resistance.

When the amorphous polyester resin A contains urethane or urea bonds with high cohesive energy, the resin has better adhesion to recording media such as paper. Furthermore, because urethane or urea bonds behave like pseudo-crosslinking points, the rubber-like properties are stronger, resulting in better heat-resistant storage stability and high-temperature offset resistance of the toner.

In other words, the toner of the present invention, when the amorphous polyester resin A and the crystalline polyester resin C are used in combination, and if necessary, other amorphous polyester resins B, achieves extremely excellent low-temperature fixability. Furthermore, by using amorphous polyester resin A, which has a glass transition temperature in the ultra-low temperature range, it becomes possible to maintain heat-resistant storage stability and high-temperature offset resistance even when the toner's glass transition temperature is set lower than conventional toners, and the lower glass transition temperature of the toner results in excellent low-temperature fixability.

<Coloring Agent>
The colorant is not particularly limited and can be appropriately selected depending on the purpose. Examples of the colorant include carbon black, nigrosine dye, iron black, naphthol yellow S, Hansa yellow (10G, 5G, G), cadmium yellow, yellow iron oxide, yellow 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), Balkan fast yellow (5G, R), tartrazine lake, quinoline yellow lake, anthrazan yellow BGL, isoindolinone yellow, red iron oxide, red lead, vermilion lead, cadmium red, cadmium mercury, Curie Red, Antimony Vermilion, Permanent Red 4R, Para Red, Faise Red, Parachlor Orthonitroaniline Red, Lithol Fast Scarlet G, Brilliant Fast Scarlet, Brilliant Carmine BS, Permanent Red (F2R, F4R, FRL, FRLL, F4RH), Fast Scarlet VD, Belcan Fast Rubin B, Brilliant Scarlet G, Lithol Rubin GX, Permanent Red F5R, Brilliant Carmine 6B, Pigment Scarlet 3B, Bordeaux 5B, Toluidine Maroon, Permanent Bordeaux Ludo 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, Perinone Orange, Oil Orange, Cobalt Blue, Cerulean Blue, Alkali Blue Lake, Peacock Blue Lake, Victoria Blue Lake, Metal-free Phthalocyanine Blue, Phthalocyanine Blue, Examples of pigments include 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 oxide, zinc white, and lithopone.

The content of the colorant is not particularly limited and can be selected appropriately depending on the purpose, but it is preferably 1 to 15 parts by weight, and more preferably 3 to 10 parts by weight, per 100 parts by weight of the toner.

The colorant can also be used as a masterbatch composited with a resin. Examples of resins used to prepare the masterbatch or to be kneaded with the masterbatch include, in addition to the amorphous polyester resins mentioned above, polymers of styrene or its substitution products, 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, and styrene-α-chloromethyl methacrylate copolymer. Examples of suitable resins include styrene copolymers such as styrene-acrylonitrile 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, polyester, epoxy resins, epoxy polyol resins, polyurethanes, polyamides, polyvinyl butyral, polyacrylic acid resins, rosin, modified rosin, terpene resins, aliphatic or alicyclic hydrocarbon resins, aromatic petroleum resins, chlorinated paraffins, and paraffin waxes. These may be used alone or in combination of two or more.

The masterbatch can be obtained by mixing and kneading the masterbatch resin and colorant under high shear force. An organic solvent can be used to enhance the interaction between the colorant and resin. The so-called flushing method, in which an aqueous paste containing the colorant in water is mixed and kneaded with the resin and organic solvent, the colorant is transferred to the resin, and the water and organic solvent components are removed, is also preferred because the colorant wet cake can be used as is, eliminating the need for drying. A high-shear dispersing device such as a three-roll mill is preferably used for mixing and kneading.

<Inorganic filler>
As the inorganic filler, the above-mentioned layered inorganic minerals are preferred, and layered inorganic minerals such as organically modified montmorillonite and organically modified smectite, in which at least a part of the ions between layers are converted with organic ions, are more preferred.Other inorganic fillers that can be used in combination include silica, alumina, titanium oxide, barium titanate, magnesium titanate, calcium titanate, strontium titanate, zinc oxide, silica sand, clay (including montmorillonite or its organically modified substance), 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, silicon nitride, etc.
The content of the inorganic filler is not particularly limited and can be appropriately selected depending on the purpose, but is preferably 0.3 parts by mass to 1.5 parts by mass, and more preferably 0.3 parts by mass to 0.7 parts by mass, relative to 100 parts by mass of the toner.

<Release Agent>
The release agent is not particularly limited and can be appropriately selected from known ones.
Examples of waxes and wax release agents include natural waxes such as vegetable waxes such as carnauba wax, cotton wax, and wood wax; animal waxes such as beeswax and lanolin; mineral waxes such as ozokerite and cerusine; and petroleum waxes such as paraffin, microcrystalline, and petrolatum.
In addition to these natural waxes, synthetic hydrocarbon waxes such as Fischer-Tropsch wax, polyethylene, and polypropylene; synthetic waxes such as esters, ketones, and ethers; and the like can also be used.

Furthermore, fatty acid amide compounds such as 12-hydroxystearic acid amide, stearic acid amide, phthalimide anhydride, and chlorinated hydrocarbons; low-molecular-weight crystalline polymer resins such as polyacrylate homopolymers or copolymers (e.g., n-stearyl acrylate-ethyl methacrylate copolymers) such as poly-n-stearyl methacrylate; and crystalline polymers with long alkyl groups on the side chains.

Among these, hydrocarbon waxes such as paraffin wax, microcrystalline wax, Fischer-Tropsch wax, polyethylene wax, and polypropylene wax are preferred.

The melting point of the release agent is not particularly limited and can be selected appropriately depending on the purpose, but is preferably 60°C or higher and 80°C or lower. A melting point of 60°C or higher can prevent the release agent from melting at low temperatures, preventing a decrease in heat-resistant storage stability. A melting point of 80°C or higher can prevent the release agent from melting sufficiently when the resin is in the fixing temperature range, preventing fixing offset and image defects.

The content of the release agent is not particularly limited and can be selected appropriately depending on the purpose. It is preferably 2 to 10 parts by weight, and more preferably 3 to 8 parts by weight, per 100 parts by weight of the toner. A content of 2 parts by weight or more can prevent a decrease in high-temperature offset resistance and low-temperature fixability during fixing, while a content of 10 parts by weight or less can prevent a decrease in heat-resistant storage stability and prevent image fogging. Having the content within the above more preferred range is advantageous in terms of improving image quality and fixing stability.

<Other ingredients>
Examples of the other components contained in the toner base particles include a charge control agent, a flowability improver, a cleaning property improver, a magnetic material, etc. Known materials can be used for these.

<Glass transition temperature [Tg1st (toner)]>
In the endothermic curve measured using a differential scanning calorimeter, the toner preferably has a glass transition temperature (Tg1st (toner)) at the first temperature rise of 20°C or more and 65°C or less, more preferably 50°C or more and 65°C or less.

Furthermore, the difference (Tg1st - Tg2nd) between the glass transition temperature of the first heating event [Tg1st (toner)] and the glass transition temperature of the second heating event [Tg2nd (toner)] in differential scanning calorimetry (DSC) of the toner is not particularly limited and can be selected appropriately depending on the purpose, but is preferably 10°C or more. There is no particular upper limit to the difference and can be selected appropriately depending on the purpose, but the difference (Tg1st - Tg2nd) is preferably 50°C or less.

A difference of 10°C or more is advantageous in terms of superior low-temperature fixability. A difference of 10°C or more means that the crystalline polyester resin and the amorphous polyester resin, which were in an incompatible state before heating (before the first temperature increase), become compatible after heating (after the first temperature increase). Note that the compatibility after heating does not need to be complete compatibility.

<External additives>
The external additive is not particularly limited and can be appropriately selected depending on the purpose, and examples thereof include silica fine particles, hydrophobic silica, fatty acid metal salts (e.g., zinc stearate, aluminum stearate, etc.), metal oxides (e.g., titania, alumina, tin oxide, antimony oxide, etc.), and fluoropolymers.

<Toner manufacturing method>
The method for producing the toner is not particularly limited and can be appropriately selected depending on the purpose. For example, it is preferred to granulate the toner by dispersing an oil phase containing the polyester resins A, B, and C, and further containing a colorant, an inorganic filler, and, if necessary, a release agent, in an aqueous medium.

Furthermore, the polyester resins A and B include a polyester resin that is a prepolymer having a urethane bond and/or a urea bond, and a polyester resin that does not have a urethane bond and/or a urea bond, preferably the crystalline polyester resin, and more preferably, are granulated by dispersing an oil phase containing the curing agent, release agent, colorant, etc., as necessary, in an aqueous medium.

As a method for producing such a toner, a known solution suspension method can be mentioned.
As an example, a method of forming toner base particles while generating a polyester resin by an elongation reaction and/or crosslinking reaction between the prepolymer and the curing agent will be described.
In this method, an aqueous medium is prepared, an oil phase containing toner materials is prepared, the toner materials are emulsified or dispersed, and the organic solvent is removed.

- Preparation of aqueous medium (aqueous phase) -
The aqueous medium can be prepared, for example, by dispersing resin particles in the aqueous medium. The amount of the resin particles added to the aqueous medium is not particularly limited and can be appropriately selected depending on the purpose, but is preferably 0.5 to 10 parts by mass per 100 parts by mass of the aqueous medium.
The aqueous medium is not particularly limited and can be appropriately selected depending on the purpose. Examples thereof include water, a solvent miscible with water, and a mixture thereof. These may be used alone or in combination of two or more. Among these, water is preferred.

The water-miscible solvent is not particularly limited and can be appropriately selected depending on the purpose. Examples thereof include alcohol, dimethylformamide, tetrahydrofuran, cellosolves, and lower ketones.
Examples of the alcohol include methanol, isopropanol, ethylene glycol, etc. Examples of the lower ketones include acetone, methyl ethyl ketone, etc.

- Preparation of oil phase -
In the present embodiment, the oil phase containing the toner materials can be prepared by dissolving or dispersing toner materials including polyester resins A and B, which are prepolymers having a urethane bond and/or a urea bond, and polyester resin C having no urethane bond and/or a urea bond, and further including the crystalline polyester resin, a curing agent, a release agent, a colorant, and the like, as needed, in an organic solvent.

There are no particular restrictions on the organic solvent and it can be selected appropriately depending on the purpose, but organic solvents with a boiling point of less than 150°C are preferred because they are easy to remove.

Examples of the organic solvent having a boiling point of less than 150°C 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.
These may be used alone or in combination of two or more.

Of these, ethyl acetate, toluene, xylene, benzene, methylene chloride, 1,2-dichloroethane, chloroform, carbon tetrachloride, etc. are preferred, with ethyl acetate being more preferred.

-Emulsification or dispersion-
The toner materials can be emulsified or dispersed by dispersing an oil phase containing the toner materials in the aqueous medium. When the toner materials are emulsified or dispersed, the curing agent and the prepolymer can undergo an elongation reaction and/or a crosslinking reaction.

The reaction conditions (reaction time, reaction temperature) for producing the prepolymer are not particularly limited and can be selected appropriately depending on the combination of the curing agent and the prepolymer. The reaction time is preferably 10 minutes to 40 hours, more preferably 2 to 24 hours. The reaction temperature is preferably 0°C to 150°C, more preferably 40°C to 98°C.

There are no particular restrictions on the method for stably forming a dispersion containing the prepolymer in the aqueous medium, and it can be selected appropriately depending on the purpose. One example is a method in which an oil phase prepared by dissolving or dispersing toner materials in a solvent is added to an aqueous medium phase, and the mixture is dispersed by shear force.

There are no particular restrictions on the disperser used for the dispersion, and it can be selected appropriately depending on the purpose. Examples include low-speed shear dispersers, high-speed shear dispersers, friction dispersers, high-pressure jet dispersers, and ultrasonic dispersers. Of these, high-speed shear dispersers are preferred because they can control the particle size of the dispersed material (oil droplets) to 2 to 20 μm.

When using the high-speed shear disperser, conditions such as rotation speed, dispersion time, and dispersion temperature can be selected appropriately depending on the purpose. The rotation speed is preferably 1,000 to 30,000 rpm, and more preferably 5,000 to 20,000 rpm. In the case of a batch method, the dispersion time is preferably 0.1 to 5 minutes. The dispersion temperature under pressure is preferably 0°C to 150°C, and more preferably 40°C to 98°C. Generally, the higher the dispersion temperature, the easier the dispersion.

There are no particular restrictions on the amount of aqueous medium used when emulsifying or dispersing the toner materials and it can be selected appropriately depending on the purpose, but it is preferably 50 to 2,000 parts by weight, and more preferably 100 to 1,000 parts by weight, per 100 parts by weight of the toner materials. Using an amount of aqueous medium of 50 parts by weight or more prevents the dispersion state of the toner materials from deteriorating, making it easier to obtain toner base particles with the desired particle size. Using an amount of aqueous medium of 2,000 parts by weight or less prevents high production costs.

When emulsifying or dispersing the oil phase containing the toner materials, it is preferable to use a dispersant to stabilize the dispersion of oil droplets, etc., to give them the desired shape, and to achieve a sharp particle size distribution.

There are no particular restrictions on the dispersant, and it can be selected appropriately depending on the purpose. Examples include surfactants, poorly water-soluble inorganic compound dispersants, and polymeric protective colloids. These may be used alone or in combination of two or more. Of these, surfactants are preferred.

The surfactant is not particularly limited and can be appropriately selected depending on the purpose. For example, anionic surfactants, cationic surfactants, nonionic surfactants, amphoteric surfactants, etc. can be used.
Examples of the anionic surfactant include alkylbenzene sulfonates, α-olefin sulfonates, and phosphate esters.
Among these, those having a fluoroalkyl group are preferred.

- Removal of organic solvents -
The method for removing the organic solvent from the dispersion liquid such as the emulsified slurry is not particularly limited and can be appropriately selected depending on the purpose. Examples of the method include a method in which the temperature of the entire reaction system is gradually increased to evaporate the organic solvent in the oil droplets, and a method in which the dispersion liquid is sprayed into a dry atmosphere to remove the organic solvent in the oil droplets.

Once the organic solvent is removed, toner base particles are formed. The toner base particles can then be washed, dried, and further classified.

The classification can be carried out by removing fine particles in the liquid using a cyclone, decanter, centrifuge, etc., or the classification can be carried out after drying.

-External additive treatment-
The obtained toner base particles may be mixed with particles of the external additive, the charge control agent, etc. At this time, by applying a mechanical impact force, it is possible to prevent the particles of the external additive, etc. from being detached from the surface of the toner base particles.

There are no particular limitations on the method for applying the mechanical impact force, and it can be selected appropriately depending on the purpose. Examples include a method in which an impact force is applied to the mixture using blades rotating at high speed, and a method in which the mixture is introduced into a high-speed air stream and accelerated to cause the particles to collide with each other or with an appropriate collision plate.

There are no particular restrictions on the equipment used in the above method, and it can be selected appropriately depending on the purpose. Examples include an Ang Mill (manufactured by Hosokawa Micron Corporation), an I-type Mill (manufactured by Nippon Pneumatic Co., Ltd.) modified to reduce the grinding air pressure, a Hybridization System (manufactured by Nara Machinery Works), a Kryptron System (manufactured by Kawasaki Heavy Industries, Ltd.), an automatic mortar, etc.

In the present invention, the volume average particle size of the toner is preferably 4.5 μm or more and 6.3 μm or less, and more preferably 5.0 μm or more and 5.8 μm or less.

(Developer)
The developer of the present invention contains at least the toner of the present invention, and optionally contains other appropriately selected components such as a carrier. Therefore, it has excellent transferability, charging properties, etc., and can stably form high-quality images. The developer may be a one-component developer or a two-component developer, but when used in a high-speed printer or the like that corresponds to the recent improvement in information processing speed, a two-component developer is preferred because of its improved lifespan.

When the developer is used as a single-component developer, there is little fluctuation in toner particle size even when the toner is balanced, and there is little toner filming on the developing roller or toner fusing to components such as blades that thin the toner layer. This results in good, stable developability and images even when stirred for long periods in the developing device.

When the developer is used as a two-component developer, there is little fluctuation in the toner particle size even when the toner is balanced over a long period of time, and good, stable developability and images can be obtained even with long-term agitation in the developing device.

<Career>
The carrier is not particularly limited and can be appropriately selected depending on the purpose, but it is preferable that the carrier has a core material and a resin layer that covers the core material.

-Core material-
The material for the core is not particularly limited and can be appropriately selected depending on the purpose, and examples thereof include manganese-strontium-based materials with a repulsion of 50 to 90 emu/g and manganese-magnesium-based materials with a repulsion of 50 to 90 emu/g. Furthermore, in order to ensure image density, it is preferable to use high-magnetization materials such as iron powder with a repulsion of 100 emu/g or more, or magnetite with a repulsion of 75 to 120 emu/g. Furthermore, it is preferable to use low-magnetization materials such as copper-zinc-based materials with a repulsion of 30 to 80 emu/g, as these materials can mitigate the impact of the developer in a standing state on the photoreceptor and are advantageous for achieving high image quality.
These may be used alone or in combination of two or more.

There are no particular restrictions on the volume average particle diameter of the core material and it can be selected appropriately depending on the purpose, but it is preferably 10 to 150 μm, and more preferably 40 to 100 μm. A volume average particle diameter of 10 μm or more prevents the carrier from containing too much fine powder, reducing the magnetization per particle and preventing carrier scattering. On the other hand, a volume average particle diameter of 150 μm or less prevents a decrease in specific surface area, preventing toner scattering and preventing poor reproduction of solid areas, especially in full-color printers with many solid areas.

The toner of the present invention can be mixed with the carrier and used in a two-component developer.
The content of the carrier in the two-component developer is not particularly limited and can be appropriately selected depending on the purpose. However, the content is preferably 90 to 98 parts by mass, and more preferably 93 to 97 parts by mass, relative to 100 parts by mass of the two-component developer.
The developer of the present invention can be suitably used for image formation by various known electrophotographic methods such as a magnetic one-component development method, a non-magnetic one-component development method, and a two-component development method.

(Image forming apparatus and image forming method)
The image forming apparatus of the present invention has at least an electrostatic latent image carrier, an electrostatic latent image forming means, and a developing means, and may further have other means as necessary. The toner used for development is the toner of the present invention.
The image forming method according to the present invention includes at least an electrostatic latent image forming step and a developing step, and may further include other steps as necessary. The toner used in the developing step is the toner of the present invention.

<Electrostatic Latent Image Carrier>
The material, structure, and size of the electrostatic latent image bearing member are not particularly limited and can be appropriately selected from known materials, and examples of the material include inorganic photoreceptors such as amorphous silicon and selenium, and organic photoreceptors such as polysilane and phthalopolymethine, etc. Among these, amorphous silicon is preferred in terms of long life.
The linear speed of the electrostatic latent image bearing member is preferably 300 mm/s or more.

<Electrostatic Latent Image Forming Unit and Electrostatic Latent Image Forming Process>
The electrostatic latent image forming means is not particularly limited as long as it is a means for forming an electrostatic latent image on the electrostatic latent image carrier, and can be appropriately selected depending on the purpose. For example, it may be a means having at least a charging member that charges the surface of the electrostatic latent image carrier, and an exposure member that exposes the surface of the electrostatic latent image carrier to light in an imagewise manner.

The electrostatic latent image forming process is not particularly limited as long as it is a process for forming an electrostatic latent image on the electrostatic latent image carrier, and can be selected appropriately depending on the purpose. For example, it can be performed by charging the surface of the electrostatic latent image carrier and then exposing it to light in an imagewise manner, and can be performed using the electrostatic latent image forming means.

<<Charging Member and Charging>>
The charging member is not particularly limited and can be appropriately selected depending on the purpose, and examples thereof include a known contact charger equipped with a conductive or semiconductive roller, brush, film, rubber blade, etc., and a non-contact charger utilizing corona discharge such as a corotron or scorotron.

The charging can be carried out, for example, by applying a voltage to the surface of the electrostatic latent image bearing member using the charging member.
The shape of the charging member may be a roller, a magnetic brush, a fur brush, or any other shape, and can be selected according to the specifications and shape of the image forming apparatus.

The charging member is not limited to the contact-type charging member, but it is preferable to use a contact-type charging member, as this results in an image forming apparatus in which the amount of ozone generated by the charging member is reduced.

<<Exposure Member and Exposure>>
The exposing member is not particularly limited and can be appropriately selected depending on the purpose as long as it can expose the surface of the electrostatic latent image bearing member charged by the charging member in the form of an image to be formed, and examples thereof include various exposing members such as a copying optical system, a rod lens array system, a laser optical system, and a liquid crystal shutter optical system.

The light source used in the exposure member is not particularly limited and can be selected appropriately depending on the purpose. Examples include fluorescent lamps, tungsten lamps, halogen lamps, mercury lamps, sodium lamps, light-emitting diodes (LEDs), semiconductor lasers (LDs), electroluminescence (EL), and other light-emitting devices.

In addition, 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 irradiate only light in the desired wavelength range.

The exposure can be carried out, for example, by exposing the surface of the electrostatic latent image bearing member to light in an imagewise manner using the exposure member.
In the present invention, a backlight system may be employed in which exposure is performed imagewise from the back side of the electrostatic latent image bearing member.

<Developing means and developing process>
The developing unit is not particularly limited as long as it is a developing unit that develops the electrostatic latent image formed on the electrostatic latent image carrier to form a toner image, which is a visible image, and is equipped with toner, and can be appropriately selected depending on the purpose.
The developing step is not particularly limited as long as it is a step of developing the electrostatic latent image formed on the electrostatic latent image carrier with a toner to form a toner image, which is a visible image, and can be appropriately selected depending on the purpose. For example, the developing step can be performed by the developing unit.
The developing means is preferably a developing device having an agitator that frictionally agitates the toner to charge it, a magnetic field generating means fixed inside, and a rotatable developer carrier that carries a developer containing the toner on its surface.

<Other means and other steps>
Examples of the other means include a transfer means, a fixing means, a cleaning means, a discharging means, a recycling means, and a control means.
Examples of the other steps include a transfer step, a fixing step, a cleaning step, a discharging step, a recycling step, and a control step.

<<Transfer means and transfer process>>
The transfer means is not particularly limited as long as it is a means for transferring a visible image onto a recording medium, and can be selected appropriately depending on the purpose. However, a preferred embodiment has a primary transfer means for transferring the visible image onto an intermediate transfer body to form a composite transfer image, and a secondary transfer means for transferring the composite transfer image onto a recording medium.
The transfer step is not particularly limited as long as it is a step of transferring a visible image onto a recording medium, and can be appropriately selected depending on the purpose. However, a preferred embodiment is one in which an intermediate transfer member is used, a visible image is primarily transferred onto the intermediate transfer member, and then the visible image is secondarily transferred onto the recording medium.
The transfer step can be carried out by, for example, charging the visible image on the photosensitive member using a transfer charger, and can be carried out by the transfer unit.

Here, when the image to be secondarily transferred onto the recording medium is a color image made up of toners of multiple colors, the transfer means can be configured to sequentially overlay toners of each color on the intermediate transfer body to form an image on the intermediate transfer body, and the intermediate transfer means can secondarily transfer the image on the intermediate transfer body onto the recording medium all at once.
The intermediate transfer member is not particularly limited and can be appropriately selected from known transfer members depending on the purpose, and a suitable example is a transfer belt.

The transfer means (the primary transfer means and the secondary transfer means) preferably includes at least a transfer device that peels and charges the visible image formed on the photosensitive member onto the recording medium. Examples of the transfer device include a corona transfer device that uses corona discharge, a transfer belt, a transfer roller, a pressure transfer roller, and an adhesive transfer device.
The recording medium is typically plain paper, but is not particularly limited as long as it can be used to transfer an unfixed image after development, and can be selected appropriately depending on the purpose. PET base for overhead projectors can also be used.

<<Fixing means and fixing process>>
The fixing unit is not particularly limited as long as it is a unit that fixes the transferred image on the recording medium, and can be appropriately selected depending on the purpose. For example, a known heating and pressing member is preferable. Examples of the heating and pressing member 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.
The fixing step is not particularly limited as long as it is a step of fixing the visible image transferred to the recording medium, and can be appropriately selected depending on the purpose. For example, the fixing step may be performed for each color toner transferred to the recording medium, or may be performed simultaneously for each color toner in a stacked state.

The fixing step can be carried out by the fixing means.
The heating temperature in the heating and pressing member is preferably 80°C to 200°C.
In the present invention, depending on the purpose, a known optical fixing device may be used together with or in place of the fixing means.
The surface pressure in the fixing step is not particularly limited and can be appropriately selected depending on the purpose, but is preferably 10 N/cm ² to 80 N/cm ² .

<<Cleaning means and cleaning process>>
The cleaning means is not particularly limited as long as it can remove the toner remaining on the photoreceptor, and can be appropriately selected depending on the purpose, such as a magnetic brush cleaner, an electrostatic brush cleaner, a magnetic roller cleaner, a blade cleaner, a brush cleaner, or a web cleaner.
The cleaning step is not particularly limited as long as it can remove the toner remaining on the photoreceptor, and can be appropriately selected depending on the purpose. For example, it can be performed by the cleaning unit.

<<Static Removal Means and Static Removal Process>>
The discharging means is not particularly limited as long as it is a means for discharging the photosensitive member by applying a discharging bias to the photosensitive member, and can be appropriately selected depending on the purpose. For example, a discharging lamp can be used.
The charge-eliminating step is not particularly limited as long as it is a step of applying a charge-eliminating bias to the photosensitive member to eliminate charges, and can be appropriately selected depending on the purpose. For example, it can be performed by the charge-eliminating unit.

<<Recycling methods and processes>>
The recycling means is not particularly limited as long as it is a means for recycling the toner removed by the cleaning step into the developing device, and can be appropriately selected depending on the purpose. For example, known conveying means can be used.
The recycling step is not particularly limited as long as it is a step of recycling the toner removed by the cleaning step into the developing device, and can be appropriately selected depending on the purpose. For example, it can be performed by the recycling means.

<<Control means and control process>>
The control means is not particularly limited as long as it is a means capable of controlling the movement of each of the means, and can be appropriately selected depending on the purpose. Examples thereof include devices such as a sequencer and a computer.
The control step is not particularly limited as long as it is a step that can control the movement of each step, and can be appropriately selected depending on the purpose, and can be performed, for example, by the control means.

Next, one embodiment of a method for forming an image using the image forming apparatus of the present invention will be described with reference to Figure 1. The color image forming apparatus 100A shown in Figure 1 includes a photosensitive drum 10 (hereinafter sometimes referred to as "photosensitive drum 10") as the electrostatic latent image carrier, a charging roller 20 as the charging means, an exposure device 30 as the exposure means, a developing unit 40 as the developing means, an intermediate transfer body 50, a cleaning device 60 as the cleaning means having a cleaning blade, and a discharging lamp 70 as the discharging means.

The intermediate transfer body 50 is an endless belt that is designed to move in the direction of the arrow via three rollers 51 positioned inside and tensioned by it. Some of the three rollers 51 also function as transfer bias rollers that apply a predetermined transfer bias (primary transfer bias) to the intermediate transfer body 50. A cleaning device 90 equipped with a cleaning blade is located near the intermediate transfer body 50. Also located near the intermediate transfer body 50 is a transfer roller 80, which serves as the transfer means and applies a transfer bias for transferring (secondary transfer) the developed image (toner image) to transfer paper 95 as a recording medium, located opposite the intermediate transfer body 50. A corona charger 58 for applying a charge to the toner image on the intermediate transfer body 50 is located around the intermediate transfer body 50, between the contact point between the photoreceptor 10 and the intermediate transfer body 50 and the contact point between the intermediate transfer body 50 and the transfer paper 95, in the direction of rotation of the intermediate transfer body 50.

The developing device 40 is composed of a developing belt 41 as the developer carrier, and a black developing unit 45K, a yellow developing unit 45Y, a magenta developing unit 45M, and a cyan developing unit 45C arranged around the developing belt 41.

The black development unit 45K is equipped with a developer container 42K, a developer supply roller 43K, and a development roller 44K. The yellow development unit 45Y is equipped with a developer container 42Y, a developer supply roller 43Y, and a development roller 44Y. The magenta development unit 45M is equipped with a developer container 42M, a developer supply roller 43M, and a development roller 44M. The cyan development unit 45C is equipped with a developer container 42C, a developer supply roller 43C, and a development roller 44C.

The developing belt 41 is an endless belt that is rotatably stretched over multiple belt rollers, with a portion of it in contact with the electrostatic latent image carrier 10.

In the color image forming apparatus 100A shown in Figure 1, for example, the charging roller 20 uniformly charges the photosensitive drum 10. The exposure device 30 exposes the photosensitive drum 10 to light in an imagewise manner, forming an electrostatic latent image.

The electrostatic latent image formed on the photosensitive drum 10 is developed with toner supplied from the developing unit 40 to form a toner image. The toner image is transferred (primary transfer) onto the intermediate transfer body 50 by voltage applied from the roller 51, and then transferred (secondary transfer) onto the transfer paper 95. As a result, a transfer image is formed on the transfer paper 95.

Residual toner on the photoreceptor 10 is removed by a cleaning device 60, and the charge on the photoreceptor 10 is temporarily removed by a discharge lamp 70.

Figure 2 shows another example of an image forming apparatus of the present invention. Image forming apparatus 100B has the same configuration as image forming apparatus 100A shown in Figure 1, except that it does not have a developing belt 41 and instead has a black developing unit 45K, a yellow developing unit 45Y, a magenta developing unit 45M, and a cyan developing unit 45C arranged directly opposite each other around the photosensitive drum 10.

Figure 3 shows another example of an image forming apparatus of the present invention. The image forming apparatus shown in Figure 3 includes a copying machine main body 150, a paper feed table 200, a scanner 300, and an automatic document feeder (ADF) 400.

An endless belt-like intermediate transfer body 50 is provided in the center of the copying machine main body 150. The intermediate transfer body 50 is stretched over support rollers 14, 15, and 16 and is rotatable clockwise in FIG. 3. An intermediate transfer body cleaning device 17 is located near support roller 15 to remove residual toner from the intermediate transfer body 50.

A tandem developing unit 120 is arranged on the intermediate transfer body 50, which is stretched between support rollers 14 and 15, along the transport direction. The tandem developing unit 120 has four image forming means 18 for yellow, cyan, magenta, and black arranged side by side facing each other. An exposure device 21, which serves as the exposure member, is arranged near the tandem developing unit 120. A secondary transfer device 22 is arranged on the side of the intermediate transfer body 50 opposite the side where the tandem developing unit 120 is arranged.

In the secondary transfer device 22, the secondary transfer belt 24, which is an endless belt, is stretched over a pair of rollers 23, and the transfer paper transported on the secondary transfer belt 24 and the intermediate transfer body 50 can come into contact with each other. The fixing device 25, which serves as the fixing means, is located near the secondary transfer device 22. The fixing device 25 includes a fixing belt 26, which is an endless belt, and a pressure roller 27 that is positioned to be pressed against the fixing belt 26.

In addition, in a tandem image forming apparatus, a sheet inverting device 28 is located near the secondary transfer device 22 and the fixing device 25 to invert the transfer paper so that images can be formed on both sides of the transfer paper.

Next, we will explain how to form a full-color image (color copy) using the tandem developing unit 120. That is, first, place the document on the document table 130 of the automatic document feeder (ADF) 400, or open the automatic document feeder 400 and place the document on the contact glass 40 of the scanner 300, and then close the automatic document feeder 400.

When the start switch is pressed, the scanner 300 starts operating after the document is transported and moved onto the contact glass 32 if the document is set on the automatic document feeder 400, or immediately after the document is set on the contact glass 32. The first and second carriages 33 and 34 then start moving. At this time, light from the light source is emitted by the first carriage 33, and the light reflected from the document surface is reflected by the mirror on the second carriage 34. The light passes through the imaging lens 35 and is received by the reading sensor 36, reading the color document (color image) and converting it into image information in black, yellow, magenta, and cyan.

Then, the image information for black, yellow, magenta, and cyan is transmitted to each image forming means 18 (black image forming means, yellow image forming means, magenta image forming means, and cyan image forming means) in the tandem developing device 120. Then, each image forming means forms a toner image for black, yellow, magenta, or cyan.

That is, as shown in FIG. 4, each image forming means 18 (black image forming means, yellow image forming means, magenta image forming means, and cyan image forming means) in the tandem developing device 120 comprises an electrostatic latent image carrier 10 (black electrostatic latent image carrier 10K, yellow electrostatic latent image carrier 10Y, magenta electrostatic latent image carrier 10M, and cyan electrostatic latent image carrier 10C), a charging device 160 that is the charging means for uniformly charging the electrostatic latent image carrier 10, and a charging device 160 that charges the electrostatic latent image carrier 10 based on each color image information. The system is equipped with an exposure device that exposes the electrostatic latent image carrier to light (L in Figure 4) in the form of an image corresponding to each color image, forming an electrostatic latent image corresponding to each color image on the electrostatic latent image carrier, a developing device 61 that develops the electrostatic latent image using each color toner (black toner, yellow toner, magenta toner, and cyan toner) to form a toner image using each color toner, a transfer charger 62 that transfers the toner image onto the intermediate transfer body 50, a cleaning device 63, and a static eliminator 64.

Each image forming means 18 is capable of forming a single-color image (black image, yellow image, magenta image, and cyan image) based on the image information for that color.

The black, yellow, magenta, and cyan images thus formed are sequentially transferred (primary transfer) onto the intermediate transfer body 50, which is rotated by support rollers 14, 15, and 16: the black image formed on the black electrostatic latent image carrier 10K, the yellow image formed on the yellow electrostatic latent image carrier 10Y, the magenta image formed on the magenta electrostatic latent image carrier 10M, and the cyan image formed on the cyan electrostatic latent image carrier 10C.

The black image, yellow image, magenta image, and cyan image are then superimposed on the intermediate transfer body 50 to form a composite color image (color transfer image).

Meanwhile, in the paper feed table 200, one of the paper feed rollers 142 is selectively rotated to feed a sheet (recording paper) from one of the paper feed cassettes 144 provided in multiple stages in the paper bank 143. The sheets are separated one by one by the separation roller 145 and sent to the paper feed path 146, then transported by the transport roller 147 and guided to the paper feed path 148 inside the copier main body 150, where they are stopped by striking the registration roller 49. Alternatively, the paper feed roller 142 is rotated to feed out sheets (recording paper) from the manual feed tray 54, which are separated one by one by the separation roller 52 and placed in the manual feed path 53, where they are also stopped by striking the registration roller 49.

The registration roller 49 is generally grounded when in use, but may also be used with a bias applied to it to remove paper dust from the sheet.

Then, the registration roller 49 rotates in time with the composite color image (color transfer image) combined on the intermediate transfer body 50, and a sheet (recording paper) is sent between the intermediate transfer body 50 and the secondary transfer device 22, and the composite color image (color transfer image) is transferred (secondary transfer) onto the sheet (recording paper) by the secondary transfer device 22. In this way, a color image is transferred and formed on the sheet (recording paper).

After image transfer, any residual toner remaining on the intermediate transfer body 50 is cleaned by the intermediate transfer body cleaning device 17.

The sheet (recording paper) onto which the color image has been transferred is transported by secondary transfer device 22 and sent to fixing device 25, where the composite color image (color transfer image) is fixed onto the sheet (recording paper) using heat and pressure. The sheet (recording paper) is then switched by switching claw 55 and discharged by discharge rollers 56, and stacked on paper output tray 57. Alternatively, the sheet can be switched by switching claw 55 and inverted by sheet inverter 28, and guided back to the transfer position, where an image is recorded on the back side as well, before being discharged by discharge rollers 56 and stacked on paper output tray 57.

(Toner storage unit)
The toner storage unit in the present invention refers to a unit having a function of storing toner and storing the toner. Examples of the toner storage unit include a toner storage container, a developing unit, and a process cartridge.
The toner container refers to a container that stores toner.
The developing device is a device that contains toner and has means for developing.
The process cartridge is a device that integrates at least an image carrier and a developing means, contains toner, and is detachably mountable to an image forming apparatus. The process cartridge may further include at least one selected from a charging means, an exposure means, and a cleaning means.

By installing the toner storage unit of the present invention in an image forming apparatus and forming an image using the toner of the present invention, it is possible to form a good image using a toner that has good low-temperature fixability, good cleanability, and does not scatter.

The toner storage container is not particularly limited and can be appropriately selected from known containers. For example, it may have a container body and a cap.

The size, shape, structure, material, etc. of the container body are not particularly limited, but it is preferable that the shape be cylindrical or the like. In particular, spiral irregularities are formed on the inner surface, so that the developer contents can be transferred to the discharge outlet side by rotating the container, and it is preferable that some or all of the spiral irregularities have a bellows function.

It is also preferable that the material have good dimensional accuracy. Examples include resin materials such as polyester resin, polyethylene resin, polypropylene resin, polystyrene resin, polyvinyl chloride resin, polyacrylic acid, polycarbonate resin components, ABS resin, and polyacetal resin.

The toner storage container is easy to store, transport, and handle, and can be detachably attached to a process cartridge, image forming device, etc., and used to replenish toner.

An example of a process cartridge related to the present invention is molded to be detachably mountable to various image forming devices, and includes at least an electrostatic latent image carrier that carries an electrostatic latent image, and developing means that develops the electrostatic latent image carried on the electrostatic latent image carrier with the toner of the present invention to form a toner image. The process cartridge of the present invention may further include other means as necessary.

The developing means includes at least a developer container that contains the developer of the present invention, and a developer carrier that supports and transports the developer contained in the developer container. The developing means may further include a regulating member or the like to regulate the thickness of the developer carried.

Figure 5 shows an example of a process cartridge related to the present invention. The process cartridge 110 has a photosensitive drum 10, a corona charger 58, a developing unit 40, a transfer roller 80, and a cleaning device 90. Note that the reference numeral 95 denotes transfer paper, and L denotes exposure light.

The present invention will be described in more detail below with reference to examples, but the present invention is not limited to these examples. Hereinafter, unless otherwise specified, "parts" means parts by mass, and "%" means % by mass. Furthermore, Examples 1, 3, and 4 refer to Reference Examples 1, 3, and 4, which are not included in the present invention.

(Production Example 1)
<Synthesis of amorphous polyester (low molecular weight polyester) resin>
A 5-liter four-neck flask equipped with a nitrogen inlet tube, a dehydration tube, a stirrer, and a thermocouple was charged with 229 parts by mass of bisphenol A ethylene oxide side 2-mol adduct, 529 parts by mass of bisphenol A propylene oxide 2-mol adduct, 208 parts by mass of terephthalic acid, 46 parts by mass of adipic acid, and 2 parts by mass of dibutyltin oxide, and the mixture was reacted at 230°C under normal pressure for 7 hours, and then further reacted under a reduced pressure of 10 mmHg to 15 mmHg for 4 hours. After that, 44 parts by mass of trimellitic anhydride was charged into the reaction vessel, and the mixture was reacted at 180°C under normal pressure for 2 hours, thereby obtaining a [non-crystalline polyester resin].

<Synthesis of Polyester Prepolymer>
Into a reaction vessel equipped with a condenser, a stirrer, and a nitrogen inlet tube, 682 parts by mass of an ethylene oxide 2-mole adduct of bisphenol A, 81 parts by mass of a propylene oxide 2-mole adduct of bisphenol A, 283 parts by mass of terephthalic acid, 22 parts by mass of trimellitic anhydride, and 2 parts by mass of dibutyltin oxide were placed, and the mixture was reacted at normal pressure at 230°C for 8 hours, and then further reacted at a reduced pressure of 10 mmHg to 15 mmHg for 5 hours to obtain an intermediate polyester.
The intermediate polyester had a number average molecular weight Mn of 2,100, a weight average molecular weight Mw of 9,500, a glass transition temperature Tg of 55° C., an acid value of 0.5 KOH mg/g, and a hydroxyl value of 51 KOH mg/g.
Next, 410 parts by mass of the [intermediate polyester], 89 parts by mass of isophorone diisocyanate, and 500 parts by mass of ethyl acetate were placed in a reaction vessel equipped with a condenser, a stirrer, and a nitrogen inlet tube, and the mixture was allowed to react at 100°C for 5 hours to obtain a [prepolymer].

<Synthesis of crystalline polyester resin>
2,300 parts by mass of 1,6-hexanediol, 2,530 parts by mass of fumaric acid, 291 parts by mass of trimellitic anhydride, and 4.9 parts by mass of hydroquinone were placed in a 5-liter four-neck flask equipped with a nitrogen inlet tube, a dehydration tube, a stirrer, and a thermocouple, and the mixture was reacted at 160°C for 5 hours, then heated to 200°C and reacted for 1 hour, and further reacted at 8.3 kPa for 1 hour to obtain a [crystalline polyester resin].

<Synthesis of Polyester Resin D-1>
In a four-neck flask equipped with a nitrogen inlet tube, a dehydration tube, a stirrer, and a thermocouple, bisphenol A ethylene oxide 2-mol adduct (BisA-EO), bisphenol A propylene oxide 3-mol adduct (BisA-PO), trimethylolpropane (TMP), terephthalic acid, and adipic acid were added in a molar ratio of bisphenol A ethylene oxide 2-mol adduct, bisphenol A propylene oxide 3-mol adduct, and trimethylolpropane (bisphenol A ethylene oxide 2-mol adduct/bisphenol A propylene oxide 3-mol adduct/trimethylolpropane). The mixture was charged with terephthalic acid and adipic acid in a molar ratio (terephthalic acid/adipic acid) of 38.6/57.9/3.5, with terephthalic acid and adipic acid in a molar ratio (terephthalic acid/adipic acid) of 85/15, and with a molar ratio of hydroxyl groups to carboxyl groups of OH/COOH of 1.12, and reacted together with titanium tetraisopropoxide (500 ppm relative to the resin components) at 230°C under normal pressure for 8 hours, and then reacted for a further 4 hours at a reduced pressure of 10 mmHg to 15 mmHg. After that, trimellitic anhydride was added to the reaction vessel in an amount of 1 mol% relative to the total resin components, and the reaction was continued at 180°C and normal pressure for 3 hours to obtain [Polyester Resin D-1].

<Preparation of Masterbatch (MB)-1>
1,200 parts of water, 500 parts of carbon black (Printex 35 manufactured by Dexa) [DBP oil absorption = 42 mL/100 mg, pH = 9.5], and 500 parts of the above [Polyester Resin D-1] were added and mixed in a Henschel mixer (manufactured by Mitsui Mining Co., Ltd.). The mixture was kneaded using two rolls at 150°C for 30 minutes, then rolled and cooled, and pulverized in a pulverizer to obtain [Masterbatch-1].

<Preparation of Wax Dispersion>
50 parts of paraffin wax (HNP-9, hydrocarbon wax, melting point 75°C, SP value 8.8, manufactured by Nippon Seiro Co., Ltd.) as [release agent 1] and 450 parts of ethyl acetate were charged into a container equipped with a stirring rod and a thermometer, and the temperature was raised to 80°C while stirring. The temperature was maintained at 80°C for 5 hours, and then cooled to 30°C over 1 hour. Dispersion was then carried out using a bead mill (Ultraviscomill, manufactured by Imex Co., Ltd.) under conditions of a liquid feed rate of 1 kg/hr, a disk peripheral speed of 6 m/sec, a filling rate of 80% by volume of zirconia beads with 0.5 mm diameter, and 3 passes to obtain [wax dispersion 1].

<Production of Organically Modified Layered Inorganic Mineral-1>
100 parts of montmorillonite was thoroughly dispersed in 200 mL of water, and 38.1 parts of dimethylstearylbenzylammonium chloride (423.5 g/mol) that had been thoroughly dissolved in water in advance was added and mixed, followed by washing, dehydration, and drying to prepare [organically modified layered inorganic mineral-1] with an organic ion modification rate of 100%.

<Production of Masterbatch-2>
2,400 parts by mass of water, 1,919 parts by mass of [organically modified layered inorganic mineral-1], and 1,570 parts by mass of the [amorphous polyester resin A] were mixed using a Henschel mixer (manufactured by Mitsui Mining Co., Ltd.). The mixture was kneaded with a two-roll mill at 150°C for 30 minutes, then rolled and cooled, and pulverized with a Pallerizer (manufactured by Hosokawa Micron Corporation) to prepare [masterbatch-2].

<Preparation of Crystalline Polyester Resin Dispersion>
A vessel equipped with a stirring rod and a thermometer was charged with 50 parts of [crystalline polyester resin] and 450 parts of ethyl acetate, and the temperature was raised to 80°C while stirring. The temperature was maintained at 80°C for 5 hours, and then the mixture was cooled to 30°C over 1 hour. Dispersion was carried out using a bead mill (Ultraviscomill, manufactured by Imex) under conditions of a liquid feed rate of 1 kg/hr, a disk peripheral speed of 6 m/sec, a filling rate of 80% by volume of zirconia beads with 0.5 mm diameter, and 3 passes to obtain [crystalline polyester resin dispersion 1].

Example 1
<Preparation of oil phase>
500 parts of [WAX Dispersion 1], 750 parts of [Crystalline Polyester Resin Dispersion 1], 750 parts of [Amorphous Polyester Resin], 750 parts of [Masterbatch-1], and 90 parts of [Masterbatch-2] were mixed in a TK Homomixer (manufactured by Tokushu Kika) at 5,000 rpm for 60 minutes. Then, using a bead mill (Ultraviscomill, manufactured by Imex Co., Ltd.), dispersion was carried out under the following conditions: a disk peripheral speed of 6 m/s, 70% by volume of 0.5 mm diameter zirconia beads, and 6 passes. The liquid feed rate was adjusted so that the entire oil phase was dispersed for an average of 0.5 minutes per pass.
Furthermore, isophorone diamine (IPDA) was added in an amount such that the molar ratio (NH2/NCO) of the amino groups of IPDA to the isocyanate groups of the [intermediate polyester] was 0.98, and the mixture was stirred for 15 seconds at 8,000 rpm using a TK homomixer. Next, 30 parts by mass of [prepolymer] prepared as a 50% by mass ethyl acetate solution was added, and the mixture was stirred for 30 seconds at 8,000 rpm using a TK homomixer to obtain [oil phase 1].

<Synthesis of organic fine particle emulsion (fine particle dispersion)>
A reaction vessel equipped with a stirring rod and a thermometer was charged with 683 parts of water, 11 parts of sodium salt of methacrylic acid ethylene oxide adduct sulfate (Eleminol RS-30: manufactured by Sanyo Chemical Industries, Ltd.), 138 parts of styrene, 138 parts of methacrylic acid, and 1 part of ammonium persulfate, and stirred at 400 rpm for 15 minutes, yielding a white emulsion. The system was heated to an internal temperature of 75°C, and allowed to react for 5 hours. Further, 30 parts of a 1% aqueous ammonium persulfate solution was added, and the mixture was aged at 75°C for 5 hours to obtain an aqueous dispersion of a vinyl resin (a copolymer of styrene-methacrylic acid-sodium salt of methacrylic acid ethylene oxide adduct sulfate) [fine particle dispersion 1]. The volume average particle diameter of [fine particle dispersion 1] measured using an LA-920 (manufactured by HORIBA) was 0.14 μm. Next, a portion of [fine particle dispersion 1] was dried to isolate the resin component.

<Preparation of aqueous phase>
990 parts of water, 83 parts of [fine particle dispersion 1], 37 parts of a 48.5% aqueous solution of sodium dodecyldiphenyletherdisulfonate (Eleminol MON-7, manufactured by Sanyo Chemical Industries, Ltd.), and 90 parts of ethyl acetate were mixed and stirred to obtain a milky white liquid, which was designated as [aqueous phase 1].

<Emulsification and desolvation>
To the vessel containing the oil phase 1, 1,200 parts of the water phase 1 was added, and the mixture was mixed for 20 minutes at 13,000 rpm using a TK homomixer to obtain an emulsified slurry 1.
[Emulsified Slurry 1] was placed in a container equipped with a stirrer and a thermometer, and the solvent was removed at 30°C for 8 hours, followed by aging at 45°C for 4 hours to obtain [Dispersed Slurry 1].

<Washing and drying>
100 parts of [Dispersion Slurry 1] was filtered under reduced pressure, and then the following operations were carried out.
(1): 100 parts of ion-exchanged water was added to the filter cake, and the mixture was mixed with a TK homomixer (at 12,000 rpm for 10 minutes) and then filtered.
(2): 100 parts of a 10% aqueous solution of sodium hydroxide was added to the filter cake of (1), and the mixture was mixed with a TK homomixer (at 12,000 rpm for 30 minutes), followed by filtration under reduced pressure.
(3): 100 parts of 10% hydrochloric acid was added to the filter cake of (2), and the mixture was mixed with a TK homomixer (at 12,000 rpm for 10 minutes) and then filtered.
(4) 300 parts of ion-exchanged water was added to the filter cake of (3), mixed with a TK homomixer (at 12,000 rpm for 10 minutes), and then filtered. This procedure was repeated twice to obtain [Filter Cake 1].
(5): [Filter cake 1] was dried in a circulating air dryer at 45° C. for 48 hours, and then sieved through a mesh with 75 μm openings to obtain [toner 1].

<Classification>
[Toner 1] was classified using an elbow jet classifier with a cut point of 5.8 μm to obtain [Toner 2] having a volume average particle size (Dv) of 6.2 μm.

<Preparation of carrier>
A resin layer coating solution was prepared by adding 100 parts by mass of a silicone resin (organostraight silicone), 5 parts by mass of γ-(2-aminoethyl)aminopropyltrimethoxysilane, and 10 parts by mass of carbon black to 100 parts by mass of toluene and dispersing the mixture for 20 minutes using a homomixer. The resin layer coating solution was applied to the surface of 1,000 parts by mass of spherical magnetite having an average particle size of 50 μm using a fluidized bed coating device to prepare a [carrier].

<Preparation of Developer>
A developer was prepared by mixing 5 parts by weight of [Toner 1] and 95 parts by weight of [Carrier] using a ball mill.

Example 2
[Toner 3] and [Toner 4] were obtained in the same manner as in Example 1, except that the amount of [Masterbatch-2] added during the <Preparation of Oil Phase> was changed to 40 parts.

Example 3
[Toner 5] and [Toner 6] were obtained in the same manner as in Example 1, except that the amount of [Masterbatch-2] added during the <Preparation of Oil Phase> was changed to 75 parts.

Example 4
[Toner 7] and [Toner 8] were obtained in the same manner as in Example 1, except that in <Preparation of oil phase> in Example 1, the amount of [Masterbatch-2] added was changed to 70 parts, the peripheral speed of the bead mill was changed to 7 m/s, and the number of passes was changed to 10 passes.

Example 5
[Toner 9] and [Toner 10] were obtained in the same manner as in Example 1, except that in <Preparation of oil phase> in Example 1, the amount of [Masterbatch-2] added was changed to 40 parts, the peripheral speed of the bead mill was changed to 7 m/s, and the number of passes was changed to 10 passes.

Example 6
[Toner 11] and [Toner 12] were obtained in the same manner as in Example 1, except that in <Preparation of oil phase> in Example 1, the amount of [Masterbatch-2] added was changed to 70 parts, the peripheral speed of the bead mill was changed to 8 m/s, and the number of passes was changed to 10 passes.

Example 7
[Toner 13] and [Toner 14] were obtained in the same manner as in Example 1, except that in <Preparation of oil phase> in Example 1, the amount of [Masterbatch-2] added was changed to 40 parts, the peripheral speed of the bead mill was changed to 8 m/s, and the number of passes was changed to 10 passes.

(Example 8)
[Toner 15] and [Toner 16] were obtained in the same manner as in Example 1, except that in <Preparation of oil phase> in Example 1, the amount of [Masterbatch-2] added was changed to 50 parts, the peripheral speed of the bead mill was changed to 8 m/s, and the number of passes was changed to 10 passes.

(Comparative Example 1)
[Toner 17] and [Toner 18] were obtained in the same manner as in Example 1, except that the amount of [Masterbatch-2] added during the <Preparation of Oil Phase> in Example 1 was changed to 30 parts.

(Comparative Example 2)
[Toner 19] and [Toner 20] were obtained in the same manner as in Example 1, except that the amount of [Masterbatch-2] added during the <Preparation of Oil Phase> in Example 1 was changed to 20 parts.

(Comparative Example 3)
[Toner 21] and [Toner 22] were obtained in the same manner as in Example 1, except that the amount of [Masterbatch-2] added during the <Preparation of Oil Phase> was changed to 90 parts.

(Comparative Example 4)
[Toner 23] and [Toner 24] were obtained in the same manner as in Example 1, except that the amount of [Masterbatch-2] added during the <Preparation of Oil Phase> in Example 1 was changed to 100 parts.

(Comparative Example 5)
[Toner 25] and [Toner 26] were obtained in the same manner as in Example 1, except that the amount of [Masterbatch-2] added during <Preparation of Oil Phase> in Example 1 was changed to 40 parts and the number of passes in the bead mill step was changed to 1.

(Comparative Example 6)
[Toner 27] and [Toner 28] were obtained in the same manner as in Example 1, except that the amount of [Masterbatch-2] added during <Preparation of Oil Phase> in Example 1 was changed to 70 parts and the number of passes in the bead mill step was changed to 1.

(Comparative Example 7)
[Toner 29] and [Toner 30] were obtained in the same manner as in Example 1, except that the amount of [Masterbatch-2] added during <Preparation of Oil Phase> in Example 1 was changed to 70 parts, and the bead mill step was not carried out.

Here, the Dv of each of the above toners is described below.
Toner 1 = 5.2 μm
Toner 2 = 6.2 μm
Toner 3 = 5.7 μm
Toner 4 = 6.8 μm
Toner 5 = 5.3 μm
Toner 6 = 6.4 μm
Toner 7 = 5.7 μm
Toner 8 = 6.8 μm
Toner 9 = 5.3 μm
Toner 10 = 6.4 μm
Toner 11 = 5.5 μm
Toner 12 = 6.6 μm
Toner 13 = 5.2 μm
Toner 14 = 6.2 μm
Toner 15 = 5.6 μm
Toner 16 = 6.7 μm
Toner 17 = 5.4 μm
Toner 18 = 6.5 μm
Toner 19 = 5.4 μm
Toner 20 = 6.5 μm
Toner 21 = 5.4 μm
Toner 22 = 6.5 μm
Toner 23 = 5.8 μm
Toner 24 = 7.0 μm
Toner 25 = 5.3 μm
Toner 26 = 6.4 μm
Toner 27 = 5.5 μm
Toner 28 = 6.6 μm
Toner 29 = 5.4 μm
Toner 30 = 6.5 μm

(evaluation)
<Cleaning ability>
After evaluating the toner scattering property described below, the degree of slip-through after cleaning of the digital full-color printer was evaluated by visually checking the amount of dirt adhering to the image carrier after cleaning, and the cleaning property was evaluated. The evaluation criteria were as follows: "Good" and "Good" were considered acceptable, and "Poor" was considered unacceptable.
[Judgment criteria]
○: No problem △: Some problem (some dirt is observed on the support)
×: Problems

<Low temperature fixability>
A copying test was conducted on Type 6200 paper (manufactured by Ricoh Co., Ltd.) using a device with a modified fixing unit of an Image MP C5002 (manufactured by Ricoh Co., Ltd.). Specifically, the fixing temperature was changed to determine the cold offset temperature (lower limit fixing temperature). The evaluation conditions for the lower limit fixing temperature were a paper feed linear speed of 200 mm/sec, a surface pressure of 1.0 kgf/ ^cm2 , and a nip width of 7 mm. The results were evaluated on a four-point scale using the following criteria: "◎", "◯", and "△" were considered pass, and "×" was considered fail.
[Evaluation Criteria for Minimum Fixing Temperature]
◎: Less than 120°C 〇: 120°C or more and less than 125°C △: 125°C or more and less than 130°C ×: 130°C or more

<Evaluation of Toner Scattering>
A chart with an image area ratio of 20% was continuously printed on 80,000 sheets using a commercially available digital full-color printer (imagio MPC6000, A4 landscape color 50 sheets/minute, manufactured by Ricoh Co., Ltd.), and the degree of toner contamination inside the printer was visually evaluated on a four-point scale according to the following criteria: "Good" and "Good" were considered acceptable, and "Poor" was considered unacceptable.
[Evaluation criteria]
◯: No toner staining is observed. △: A little toner staining is observed. ×: Toner staining is observed.

<Toner Evaluation>
The toner of each example was measured by X-ray fluorescence elemental analysis (XRF) to determine the atomic concentration % of Al.
Further, the atomic concentration % of Al in each example toner as measured by X-ray photoelectron spectroscopy (XPS) was determined as M1, and the atomic concentration % of Al as measured by XRF was determined as M2.
Furthermore, when the volume average particle diameter of the toner is Dv, the atomic concentration % of Al when the particles of the toner classified into 6/5Dv are measured by XPS is M3, and the atomic concentration % of Al when the particles of the toner classified into 6/5Dv are measured by XRF is M4, (M1/M2)/(M3/M4) was calculated.
The measurement method is as described above.

The results are shown in Table 1.

10 Electrostatic latent image carrier (photosensitive drum)
10K Black electrostatic latent image carrier 10Y Yellow electrostatic latent image carrier 10M Magenta electrostatic latent image carrier 10C Cyan electrostatic latent image carrier 14 Support roller 15 Support roller 16 Support roller 17 Cleaning device 18 Image forming means 20 Charging roller 21 Exposure device 22 Secondary transfer device 23 Roller 24 Secondary transfer belt 25 Fixing device 26 Fixing belt 27 Pressure roller 28 Sheet reversing device 32 Contact glass 33 First traveling body 34 Second traveling body 35 Imaging lens 36 Reading sensor 40 Developer 41 Development belt 42K Developer container 42Y Developer container 42M Developer container 42C Developer container 43K Developer supply roller 43Y Developer supply roller 43M Developer supply roller 43C Developer supply roller 44K Development roller 44Y Development roller 44M Development roller 44C Developing roller 45K, black developing unit 45Y, yellow developing unit 45M, magenta developing unit 45C, cyan developing unit 49, registration roller 50, intermediate transfer body 51, roller 52, separation roller 53, manual paper feed path 54, manual feed tray 55, switching claw 56, discharge roller 57, discharge tray 58, corona charging device 60, cleaning device 61, developing device 62, transfer charger 63, cleaning device 64, discharge lamp 70, discharge lamp 80, transfer roller 90, cleaning device 95, transfer paper 100A, 100B, 100C, image forming apparatus 110, process cartridge 120, tandem type developing unit 130, document table 142, paper feed roller 143, paper bank 144, paper feed cassette 145, separation roller 146, paper feed path 147, transport roller 148, paper feed path 150, copying apparatus main body 160, charging device 200, paper feed table 300 Scanner 400 Automatic Document Feeder (ADF)

Japanese Patent Application Publication No. 11-133665 Japanese Patent Application Laid-Open No. 2002-287400 Japanese Patent Application Laid-Open No. 2002-351143 Patent No. 2579150 Japanese Patent Application Laid-Open No. 2001-158819 Japanese Patent Application Laid-Open No. 2004-46095 Japanese Patent Application Laid-Open No. 2007-271789 JP 2017-167370 A

Claims (8)

A toner containing at least a binder resin, a colorant, and an inorganic filler,
the toner has an Al atomic concentration % of 0.35 or more and 0.85 or less when measured by X-ray fluorescence elemental analysis (XRF);
where M1 is the atomic concentration % of Al in the toner measured by X-ray photoelectron spectroscopy (XPS), M2 is the atomic concentration % of Al measured by XRF, and Dv is the volume average particle size of the toner, M3 is the atomic concentration % of Al in particles classified into 6/5 Dv measured by XPS, and M4 is the atomic concentration % of Al in particles classified into 6/5 Dv measured by XRF, the relationship of 0.8<(M1/M2)/(M3/M4)<1.2 is satisfied,
The (M1/M2) ratio exceeds 1.4,
The toner , wherein the binder resin contains a crystalline polyester resin, and the amount of the crystalline polyester resin is 3 parts by mass or more and 20 parts by mass or less per 100 parts by mass of the toner . The toner according to claim 1, characterized in that the atomic concentration (%) of Al measured by X-ray fluorescence elemental analysis (XRF) of the toner is 0.4 or more and 0.8 or less. The toner described in 1 or 2, characterized in that the atomic concentration (%) of Al measured by X-ray fluorescence elemental analysis (XRF) is 0.4 or more and 0.6 or less. The toner according to any one of claims 1 to 3, characterized in that (M1/M2)/(M3/M4) satisfies the relationship 0.9<(M1/M2)/(M3/M4)<1.1. A developer comprising the toner according to any one of claims 1 to 4 and a carrier. A toner storage unit containing the toner according to any one of claims 1 to 4 . an electrostatic latent image carrier; an electrostatic latent image forming means for forming an electrostatic latent image on the electrostatic latent image carrier; and a developing means having a toner for developing the electrostatic latent image formed on the electrostatic latent image carrier to form a visible image;
5. An image forming apparatus, wherein the toner is the toner according to claim 1 . The method includes: an electrostatic latent image forming step of forming an electrostatic latent image on an electrostatic latent image carrier; and a developing step of using a toner to develop the electrostatic latent image formed on the electrostatic latent image carrier and form a visible image,
5. An image forming method, wherein the toner is the toner according to claim 1 .