JP7254604B2 - toner - Google Patents

Description

The present invention relates to a toner used in electrophotography, electrostatic recording, electrostatic printing, and the like.

In recent years, with the widespread use of electrophotographic full-color copiers, the demand for high-speed printing and energy saving has increased. Furthermore, in the field of commercial printing, where the printed matter itself is a commodity, not only productivity but also higher quality and more stable images are more strongly desired than ever before.
Specifically, there is a demand for a toner with a small particle size in order to cope with high image quality. A small particle size toner can improve dot reproducibility and improve image quality. However, when the influence of the adhesive force between toner particles increases due to the smaller particle size of the toner, the cohesive force of the toner increases. As a result, there are cases where the developability is lowered and the image density is lowered. In particular, during long-term use, this tendency was remarkable both at the initial stage and after use. In addition, the smaller the particle size, the lower the cleanability, and the charging member may be contaminated by slipping through the cleaning blade, resulting in a change in image density.
Therefore, it has been proposed to provide a toner that has a stable image density even under long-term durability conditions and suppresses the occurrence of cleaning defects by setting the coverage ratio and embedding ratio of the external additive of the toner within a specific range (Patent Document 1). 1).

JP 2015-28601 A

However, since it has a uniform coverage rate and embedding rate regardless of the particle size, the non-electrostatic adhesion force on the fine powder side becomes relatively high when deteriorated due to embedding of the external additive. As a result, the developability of the toner from the developer bearing member to the electrostatic latent image bearing member deteriorates, and image density and image density uniformity may deteriorate during long-term use.
Therefore, there is a demand for a toner that exhibits good developability and excellent cleanability even during long-term use.
SUMMARY OF THE INVENTION An object of the present invention is to provide a toner that solves the above problems. Specifically, it is an object of the present invention to provide a toner that exhibits excellent developability and cleanability even during long-term use.

The present invention provides toner particles containing a binder resin and a colorant, and a toner containing an external additive,
the median diameter (D50) of the toner based on the number of particles is 3.0 μm or more and 6.0 μm or less;
With regard to the surface height of the toner particle surface due to the external additive, which is obtained by scanning electron microscopy (SEM) of the toner, the surface height of the toner having a particle size less than the median diameter (D50) is HS [nm]. The toner satisfies the following formulas (1) and (2), where HL [nm] is the surface height of the toner having a particle diameter equal to or larger than the median diameter (D50).
61≤HS≤300 (1)
1.1≤HS/HL≤3.0 (2)

According to the present invention, it is possible to provide a toner that exhibits excellent developability and cleanability even during long-term use.

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, embodiments for carrying out the present invention will be described in detail.

The toner of the present invention contains toner particles containing a binder resin and a colorant, and an external additive, and has a median diameter (D50) of 3.0 μm or more and 6.0 μm or less based on the number of the toner particles. With respect to the surface height of the toner particle surface due to the external additive, which is obtained by scanning electron microscope (SEM) of the toner, the surface height of the toner having a particle size less than the median diameter (D50) is defined as HS [ nm] and the surface height of the toner having a particle size equal to or larger than the median diameter (D50) is HL [nm], the following formulas (1) and (2) are satisfied.
HS≤300 (1)
1.1≤HS/HL≤3.0 (2)

The toner of the present invention is a toner that exhibits excellent developability and cleanability even when used for a long period of time, and therefore can stably output high-quality images for a long period of time.

In the present invention, the reason why the above problems have been solved is not necessarily clear, but the present inventors presume as follows.

Adhesion forces between toner particles can be divided into electrostatic and non-electrostatic. If the size of the toner particles is reduced, the charge amount per toner particle decreases if the charge amount per mass is constant, so the influence of the adhesion force due to non-electrostatic factors becomes relatively high. Therefore, reducing the non-electrostatic adhesion becomes more important. Therefore, in order to reduce the non-electrostatic adhesion force of the toner, it has been conventionally proposed to add an external additive having a large particle size such as inorganic fine particles. However, since the non-electrostatic adhesive force of the toner as a whole is lowered, the fluidity of the coarse powder side becomes excessively low, resulting in a difference in the fluidity of the toner as a whole. If there is a difference in toner fluidity, cleaning cannot be performed uniformly, and especially when the toner has a small particle size, the toner easily slips through the cleaning blade. As a result, the charging member may be contaminated and the density uniformity may be deteriorated.

The present inventors have found that these problems can be solved by controlling each particle size when adding an external additive to lower the cohesive force. Specifically, the inventors have found that these problems can be solved by making the height of the external additive on the surface of toner particles with small particle diameters and having high cohesive force higher than the height of the surface of toner particles with large particle diameters. .

The configuration of the toner preferable for achieving the object of the present invention will be described in detail below.

The toner of the present invention has a number-based median diameter (D50) of 3.0 μm or more and 6.0 μm or less. When D50 is within the above range, dot reproducibility is improved and excellent image quality is obtained. On the other hand, when D50 is less than 3.0 μm, the amount of fine powder is excessively large, causing toner spent on the magnetic carrier during long-term image output, lowering fluidity of the developer, and preventing stable charging. Good image quality is difficult to obtain.

In the toner of the present invention, the surface height of the toner particles having a particle diameter less than the median diameter (D50) of the surface height of the toner particle surface due to the external additive, which is obtained by scanning electron microscopy (SEM) of the toner. When the thickness is HS [nm], HS is 300 nm or less, preferably 70 nm or more and 200 nm or less, more preferably 100 nm or more and 170 nm or less. When the HS is within the above range, the height of the inorganic fine particles on the surface of the toner particles having a small particle size is sufficiently ensured, the cohesive force can be lowered, and excellent developability can be obtained.

The toner of the present invention relates to the surface height of the toner particle surface due to the external additive, which is determined by a scanning electron microscope (SEM) of the toner. When the thickness is HL [nm], HS/HL is 1.1 or more and 3.0 or less, preferably 1.2 or more and 2.0 or less. When the HS/HL relationship is within the above range, the difference in fluidity between large particle size toners and small particle size toners is suppressed, and the difference in developability for each particle size is reduced, resulting in excellent image density uniformity. In addition, in general, when the toner is used for a long period of time, the external additive is embedded in the surface of the toner particles, resulting in increased adhesion. In particular, a toner with a small particle size has a large contact area and number of times with other members such as a carrier, so that the embedding speed of the external additive increases, and the difference in adhesion due to the difference in particle size increases. However, in the toner of the present invention, the height of the external additive is controlled within an appropriate range for each particle size, so the difference in adhesion force due to particle size can be suppressed.

The external additive for the toner of the present invention preferably has a number-based average particle size of 80 nm or more and 300 nm or less, more preferably silica fine particles of 90 nm or more and 200 nm or less. When the average particle size of the external additive is within the above range, HS and HL can be easily controlled in the desired optimum range, the maximum spacer effect can be expressed, and the non-electrostatic adhesion force can be reduced. Developability is obtained.

The toner of the present invention preferably has a span value of (D90-D10)/D50 of 0.7 or less, more preferably 0.6 or less. When the span value of the toner is within the above range, it means that the particle size distribution is sharp, and there are few fine particles that are excessively small and the charge amount per particle is considerably small. As a result, the occurrence of image fogging due to low-charge toner is suppressed, and a higher quality image can be obtained.

In the present invention, the configuration of the preferred toner will be described in detail below.

[Binder resin]
Examples of the binder resin used for the toner particles of the toner of the present invention include the following polymers.

Homopolymers of styrene and substituted products thereof such as polystyrene, poly-p-chlorostyrene and polyvinyltoluene;
Styrene-p-chlorostyrene copolymer, styrene-vinyltoluene copolymer, styrene-vinylnaphthalene copolymer, styrene-acrylate copolymer, styrene-methacrylate copolymer, styrene-α-chloromethacryl methyl acid copolymer, styrene-acrylonitrile copolymer, styrene-vinyl methyl ether copolymer, styrene-vinyl ethyl ether copolymer, styrene-vinyl methyl ketone copolymer, styrene-acrylonitrile-indene copolymer, etc. styrenic copolymer;
Polyvinyl chloride, phenol resin, natural modified phenol resin, natural resin modified maleic acid resin, acrylic resin, methacrylic resin, polyvinyl acetate, silicone resin, polyester, polyurethane, polyamide, furan resin, epoxy resin, xylene resin, polyvinyl butyral, Terpene resins, coumarone-indene resins, petroleum-based resins.

Among these, polyester is preferably used from the viewpoint of low-temperature fixability and chargeability of the toner.

[wax]
The toner particles of the toner of the present invention may contain wax. Examples of wax include the following.

Hydrocarbon waxes such as low-molecular-weight polyethylene, low-molecular-weight polypropylene, alkylene copolymers, microcrystalline wax, paraffin wax, and Fischer-Tropsch wax;
Hydrocarbon wax oxides such as oxidized polyethylene wax or block copolymers thereof;
waxes mainly composed of fatty acid esters such as carnauba wax;
A partly or wholly deoxidized fatty acid ester such as deoxidized carnauba wax.

Among these, hydrocarbon waxes such as paraffin wax and Fischer-Tropsch wax, and fatty acid ester waxes such as carnauba wax are preferable from the viewpoint of low-temperature fixability and hot offset resistance of the toner.

In the present invention, a hydrocarbon wax is more preferable from the viewpoint of the hot offset resistance of the toner.

The wax content in the toner particles is preferably 1 part by mass or more and 20 parts by mass or less with respect to 100 parts by mass of the binder resin in the toner particles. When the wax content is within the above range, the hot offset resistance at high temperatures is further improved.

Further, from the viewpoint of achieving both the storage stability and the hot offset resistance of the toner, it is preferable that the peak temperature of the maximum endothermic peak of the toner satisfies the following.

That is, in the endothermic curve during temperature rise measured by a differential scanning calorimeter (DSC), the peak temperature of the maximum endothermic peak present in the temperature range of 30° C. or higher and 200° C. or lower is 50° C. or higher and 110° C. or lower. is preferred.

[Coloring agent]
The toner particles of the toner of the present invention may contain a colorant. As the colorant, a known yellow colorant, magenta colorant, cyan colorant, and black colorant can be used.

Examples of black colorants include carbon black, and black tones obtained by using a yellow colorant, a magenta colorant and a cyan colorant.

As the colorant, a pigment or dye may be used alone, or a dye and a pigment may be used in combination.

The content of the colorant in the toner particles is preferably 0.1 parts by mass or more and 30.0 parts by mass or less with respect to 100.0 parts by mass of the binder resin in the toner particles.

[Magnetic material]
The toner of the present invention may be magnetic toner or non-magnetic toner. When used as a magnetic toner, it is preferable to use magnetic iron oxide as a magnetic material to be contained in the toner particles. Magnetic iron oxides include, for example, magnetite, maghematite, and ferrite.

The content of the magnetic material in the toner particles is preferably 25 parts by mass or more and 95 parts by mass or less, more preferably 30 parts by mass or more and 45 parts by mass or less with respect to 100 parts by mass of the binder resin in the toner particles. is.

[Charge control agent]
The toner particles of the toner of the present invention may contain a charge control agent. Charge control agents include negative charge control agents and positive charge control agents. Examples of negative charge control agents include metal salicylate compounds, metal naphthoate compounds, metal dicarboxylic acid compounds, polymeric compounds having sulfonic acid or carboxylic acid side chains, and sulfonate or sulfonate ester side chains. , high molecular weight compounds having a carboxylate or carboxylic acid ester in the side chain, boron compounds, urea compounds, silicon compounds, calixarene, and the like.

When the charge control agent is contained in the toner particles, the charge control agent may be added internally or externally to the toner particles.

The content of the charge control agent in the toner particles is preferably 0.2 parts by mass or more and 10.0 parts by mass or less with respect to 100.0 parts by mass of the binder resin in the toner particles.

[External Additive]
Examples of external additives used in the toner of the present invention include silicon oxide (silica), aluminum oxide (alumina), titanium oxide (titania), magnesium oxide, zirconium oxide, chromium oxide, cerium oxide, tin oxide, and zinc oxide. fine particles of metal oxides such as In addition, fine particles such as amorphous carbon (carbon black, etc.), nitrides (silicon nitride, etc.), carbides (silicon carbide, etc.), metal salts (strontium titanate, calcium sulfate, barium sulfate, calcium carbonate, etc.) can also be mentioned. be done. Examples of external additives other than inorganic fine particles include resin fine particles such as vinyl resins, polyesters, and silicone resins.

The external additives as described above may be used singly, or may be used in combination of multiple types or in combination of multiple types.

In the present invention, the external additive is preferably inorganic fine particles, particularly preferably silica fine particles. These inorganic fine particles are particularly preferably hydrophobized with a hydrophobizing agent such as a silane compound, silicone oil or a mixture thereof.

Examples of methods for hydrophobizing inorganic fine particles include a method of chemically treating them with an organic silicon compound that reacts with the inorganic fine particles or an organic silicon compound that physically adsorbs silica fine powder. A preferred method is to treat inorganic fine particles produced by vapor phase oxidation of a silicon halide compound with an organosilicon compound. Examples of organosilicon compounds include the following. Hexamethyldisilazane, trimethylsilane, trimethylchlorosilane, trimethylethoxysilane, dimethyldichlorosilane, methyltrichlorosilane, allyldimethylchlorosilane, allylphenyldichlorosilane, benzyldimethylchlorosilane, bromomethyldimethylchlorosilane, α- Chlorethyltrichlorosilane, β-Chlorethyltrichlorosilane, Chlormethyldimethylchlorosilane, Triorganosilylmercaptan, Trimethylsilylmercaptan, Triorganosilyl acrylate, Vinyldimethylacetoxysilane, Dimethylethoxysilane, Dimethyldimethoxysilane, Diphenyldiethoxysilane, 1 - hexamethyldisiloxane, 1,3-divinyltetramethyldisiloxane, 1,3-diphenyltetramethyldisiloxane, and dimethylpolysiloxane. These are used singly or as a mixture of two or more.

The inorganic fine particles may be treated with silicone oil, or may be treated with a combination of silicone oil and the organosilicon compound. The silicone oil preferably has a viscosity of 30 mm ² /s or more and 1000 mm ² /s or less at 25°C. Examples thereof include dimethylsilicone oil, methylphenylsilicone oil, α-methylstyrene-modified silicone oil, chlorophenylsilicone oil, and fluorine-modified silicone oil.

Examples of methods for hydrophobicizing inorganic fine particles with silicone oil include the following methods. A method of directly mixing inorganic fine particles treated with a silane coupling agent and silicone oil using a mixer such as a Henschel mixer; a method of spraying silicone oil onto silica fine powder as a base. Alternatively, after dissolving or dispersing silicone oil in a suitable solvent, silica fine powder is added and mixed to remove the solvent. More preferably, the silicone oil-treated silica is obtained by heating silica in an inert gas at a temperature of 200° C. or higher, more preferably 250° C. or higher, to stabilize the surface coating after treatment with silicone oil.

The content of the external additive used in the toner of the present invention is preferably 1.5 parts by mass or more and 10.0 parts by mass or less with respect to 100.0 parts by mass of the toner particles.

[Other external additives]
To the toner of the present invention, other external additives are added to improve the fluidity of the toner and adjust the amount of triboelectrification, although they do not affect the above formulas (1) and (2). may

As external additives other than the above, inorganic fine particles such as silicon oxide (silica), aluminum oxide (alumina), titanium oxide (titania), strontium titanate, and calcium carbonate are preferable.

Examples of external additives other than inorganic fine particles include resin fine particles such as vinyl resins, polyesters, and silicone resins.

These inorganic fine particles and resin fine particles function as toner chargeability control, fluidity and cleaning aids.

[Mixing of Toner Particles and External Additive]
For mixing the toner particles and the external additive, known mixers such as Henschel mixer, doublecon mixer, V type mixer, drum type mixer, super mixer, Nauta mixer, and Mechanohybrid (manufactured by Nippon Coke Kogyo Co., Ltd.) are used. A mixer can be used.

[Career]
The toner of the present invention is preferably mixed with a magnetic carrier and used as a two-component developer from the viewpoint that stable images can be obtained over a long period of time. Magnetic carriers include, for example, surface-oxidized iron powder or unoxidized iron powder, metal particles such as iron, lithium, calcium, magnesium, nickel, copper, zinc, cobalt, manganese, rare earths, or alloys thereof. magnetic particles such as magnetic particles, oxide particles, and ferrite; and magnetic material-dispersed resin carriers (so-called resin carriers) containing magnetic particles and a binder resin that holds the magnetic particles in a dispersed state. A carrier can be used.

When the toner of the present invention is mixed with a magnetic carrier and used as a two-component developer, the carrier mixing ratio at that time is preferably 2% by mass or more and 15% by mass or less as the toner concentration in the two-component developer. , more preferably 4% by mass or more and 13% by mass or less, usually good results can be obtained.

[Method for producing toner particles]
The toner particles of the present invention can be produced by a known method for producing toner particles such as a melt-kneading method, an emulsion aggregation method, and a dissolution suspension method.

An example of the toner manufacturing procedure by the pulverization method will be described below.

In the raw material mixing step, predetermined amounts of other components such as a binder resin containing an amorphous polyester resin, a wax, a colorant, and, if necessary, a charge control agent are weighed as materials constituting the toner particles. Blend and mix. Examples of the mixing device include a double-con mixer, a V-type mixer, a drum-type mixer, a super mixer, a Henschel mixer, a Nauta mixer, and a Mechanohybrid (manufactured by Nippon Coke Kogyo Co., Ltd.).

Next, the mixed materials are melt-kneaded to disperse wax and the like in the binder resin. In the melt-kneading process, a batch-type kneader such as a pressure kneader or a Banbury mixer, or a continuous kneader can be used, and single-screw or twin-screw extruders are the mainstream because of their superiority in continuous production. ing. For example, KTK type twin-screw extruder (manufactured by Kobe Steel, Ltd.), TEM type twin-screw extruder (manufactured by Toshiba Machine Co., Ltd.), PCM kneader (manufactured by Ikegai Iron Works), twin-screw extruder (K.C.K. ), Co-kneader (manufactured by Buss Co., Ltd.), Kneedex (manufactured by Nippon Coke Industry Co., Ltd.), and the like. Furthermore, the resin composition obtained by melt-kneading may be rolled with two rolls or the like and cooled with water or the like in the cooling step.

The cooled resin composition is then pulverized to a desired particle size in a pulverization step. In the pulverization process, for example, after coarse pulverization with a pulverizer such as a crusher, hammer mill, or feather mill, further, for example, Kryptron System (manufactured by Kawasaki Heavy Industries, Ltd.), Super Rotor (manufactured by Nisshin Engineering Co., Ltd.), Turbo Mill (manufactured by Turbo Kogyo Co., Ltd.) or a fine pulverizer using an air jet method.

After that, classification such as inertial classification Elbow Jet (manufactured by Nittetsu Mining Co., Ltd.), centrifugal force classification method Turboplex (manufactured by Hosokawa Micron), TSP Separator (manufactured by Hosokawa Micron), Faculty (manufactured by Hosokawa Micron), etc. The toner is classified using a machine or a sieving machine to obtain a classified product (toner particles). Among them, Faculty (manufactured by Hosokawa Micron Corporation) is preferable from the point of view of improvement in transfer efficiency because it can perform spheroidizing treatment of toner particles at the same time as classification.

In addition, if necessary, after pulverization, a hybridization system (manufactured by Nara Machinery Co., Ltd.), a mechanofusion system (manufactured by Hosokawa Micron Corporation), a faculty (manufactured by Hosokawa Micron Corporation), or a Meteor Rainbow MR Type (manufactured by Nippon Pneumatic Co., Ltd.) is used. It is also possible to carry out surface treatment of the toner particles such as spheroidizing treatment.

After that, it is divided into a fine powder side and a coarse powder side. For example, it is divided into two using an inertial classification type elbow jet (manufactured by Nittetsu Mining Co., Ltd.). Inorganic fine particles having different average particle diameters are externally added to the surfaces of the bisected toner particles.

As a method for external addition treatment, toner particles and various known external additives are blended in predetermined amounts, and mixed with a double-con mixer, V-type mixer, drum-type mixer, super mixer, Henschel mixer, Nauta mixer, and Mechanohybrid (Nippon Coke Kogyo Co., Ltd.). (manufactured by Hosokawa Micron Corporation) or Nobilta (manufactured by Hosokawa Micron Corporation).

Next, methods for measuring physical properties related to the present invention will be described.

<Measurement of Median Diameter (D50) Based on the Number of Toners>
The number-based median diameter (D50) of the toner of the present invention can be obtained by observation of a secondary electron image with a scanning electron microscope and subsequent image processing.

The median diameter (D50) based on the number of toner particles of the present invention was measured using a scanning electron microscope (SEM) S-4800 (manufactured by Hitachi Ltd.).

Specifically, the toner was fixed in a single layer on a sample table for electron microscope observation with a carbon tape, platinum was vapor-deposited, and a scanning electron microscope S-4800 (manufactured by Hitachi, Ltd.) was observed under the following conditions. ) was observed. Observation is performed after performing the flushing operation.
SignalName=SE(U, LA80)
Accelerating Voltage = 2000 Volts
Emission Current = 10000nA
Working distance = 6000um
Lens Mode = High
Condenser 1 = 5
ScanSpeed=Slow4 (40 seconds)
Magnification=50000
DataSize = 1280 x 960
ColorMode=Grayscale

The secondary electron image was obtained by adjusting the brightness to 'contrast 5, brightness -5' on the control software of the scanning electron microscope S-4800, capturing speed/accumulated number 'Slow 4 for 40 seconds', and image size 1280 x 960 pixels. A projected toner image was obtained as an 8-bit 256-gradation grayscale image. From the scale on the image, the length of 1 pixel is 0.02 μm, and the area of 1 pixel is 0.0004 μm ² .

Subsequently, 100 toner grains were analyzed using the projection image obtained by the secondary electrons. The details of the method of selecting 100 toner particles to be analyzed will be described later. Image processing software Image-Pro Plus 5.1J (manufactured by Media Cybernetics) was used.

Next, the portion of the toner particles was extracted, and the size of one extracted toner particle was counted. Specifically, first, in order to extract the toner particle clusters to be analyzed, the toner particle clusters and the background portion are separated. Select Image-Pro Plus 5.1J "Measurement" - "Count/Size". In the "Brightness range selection" of "Count/size", the brightness range was set in the range of 50 to 255, and the low-brightness carbon tape part that was reflected as the background was excluded, and the toner particle group was extracted. . When the toner particles are fixed by a method other than the carbon tape, the background does not necessarily have a low brightness area, or there is a possibility that the brightness is partially the same as that of the toner particles. However, the boundary between the toner particles and the background can be easily distinguished from the secondary electron observation image. When extracting, in the "Count/Size" extraction option, select 4 connections, enter a smoothness of 5, check "Fill holes", and remove toner particles and other The toner particles overlapping with the toner particles of are excluded from the calculation. Next, the area and Feret diameter (average) were selected as the measurement items of "count/size", and each toner grain for image analysis was extracted with the area selection range set to 100 pixels minimum and 10000 pixels maximum. One toner particle was selected from the extracted toner particle group, and the size (number of pixels) of the portion derived from that particle was determined (ja). From the obtained ja, the projected area circle equivalent diameter d1 was obtained using the following formula.
d1={(4*ja*0.3088)/3.14} ^(1/2)

Then, each particle of the extracted particle group was subjected to the same processing until 100 toner particles were selected. When the number of toner particles in one field of view was less than 100, the same operation was repeated for the projected toner image in another field of view.

The 100 toner particles thus obtained were arranged in ascending order of projected area equivalent circle diameter, and the projected area equivalent circle diameter of the 50th toner particle was defined as the median diameter (D50) based on the number of toner particles of the present invention.

<Measurement of Height of Toner Particle Surface by External Additive>
The height of the toner particle surface of the present invention due to the external additive can be obtained by observing a secondary electron image with a 3D-scanning electron microscope. In the present invention, an electron beam three-dimensional roughness analyzer ERA-9000 (manufactured by Elionix) was used. The observation magnification is set to 50,000 times, and the three-dimensional surface shape data of each toner particle surface is measured for a total of 30 toner particles. High-pass filtered height distribution data was obtained with an acceleration voltage of 1.0 kV, a measurement area of 2.4 μm×1.8 μm, a measurement interval of 0.5 μm, and a cutoff wavelength of 0.6 μm. The average value of the peak values of the histogram obtained by the above method was taken as the height of the external additive on the surface of the toner particles in the present invention.

<Method for measuring average particle size of external additive based on number>
The average particle size of the primary particles of the external additive on a number basis is measured using a transmission electron microscope (TEM) "JEM2800" (manufactured by JEOL Ltd.).

First, the measurement sample is adjusted. 1 ml of isopropanol is added to about 5 mg of the external additive, and dispersed for 5 minutes with an ultrasonic disperser (ultrasonic cleaner). Next, one drop of the above-mentioned dispersion liquid was placed on a microgrid (150 mesh) with a supporting film for TEM, and dried to prepare a measurement sample.

Next, with a transmission electron microscope (TEM), under the condition of an accelerating voltage of 200 kV, an image is acquired at a magnification (for example, 200 k to 1 M times) at which the external additive in the field of view can be sufficiently measured. The particle size of 100 primary particles of the external additive is measured to determine the number-based average particle size. The particle size of the primary particles may be measured manually or using a measuring tool.

The present invention will be described in more detail below with reference to examples. In the following description, parts are based on parts by mass.

<Production example of binder resin>
<Production example of polyester resin>
・Polyoxypropylene (2.2)-2,2-bis(4-hydroxyphenyl)propane: 100.0 mol%
・Terephthalic acid: 80.0 mol% with respect to the total number of moles of polyvalent carboxylic acid
- Trimellitic anhydride: 20.0 mol% with respect to the total number of moles of polyvalent carboxylic acid
The above monomer material was charged into a reactor equipped with a condenser, stirrer, nitrogen inlet tube and thermocouple. Then, 1.5 parts of tin 2-ethylhexanoate was added as a catalyst (esterification catalyst) to 100 parts of the total amount of the monomer materials. Next, after the inside of the reactor was replaced with nitrogen gas, the temperature was gradually raised while stirring, and the reaction was carried out for 2 hours while stirring at a temperature of 200°C.

Furthermore, the pressure in the reaction tank was lowered to 8.3 kPa and maintained for 1 hour, then cooled to 180, reacted as it was, and after confirming that the softening point measured according to ASTM D36-86 reached 122 ° C. The temperature was lowered to stop the reaction.

The obtained polyester resin had a softening point (Tm) of 112°C and a glass transition temperature (Tg) of 63°C.

<Production example of inorganic fine particles>
<Production example of silica fine particles 1>
In producing silica fine particles 1, a hydrocarbon-oxygen mixed burner having a double-tube structure capable of forming an inner flame and an outer flame was used as a combustion furnace. This burner is configured such that a two-fluid nozzle for slurry injection is grounded at the center of the burner, and a silicon compound as a raw material is introduced. In addition, a hydrocarbon-oxygen combustible gas is injected from around the two-fluid nozzle to form an inner flame and an outer flame, which are reducing atmospheres. By controlling the amount and flow rate of the combustible gas and oxygen, the atmosphere, temperature, flame length, etc. can be adjusted. In addition, in the flame, silica fine particles are generated from the raw material silicon compound, and the silica fine particles can be fused until they reach a desired particle size. Thereafter, the silica fine particles having a desired particle size are obtained by cooling and collecting the produced silica fine particles with a bag filter or the like.

Silica microparticles were produced using hexamethylcyclotrisiloxane as a raw silicon compound. Next, 100 parts of the obtained silica fine particles were surface-treated with 10 parts of hexamethyldisilazane to obtain silica fine particles 1 having a number-based average particle diameter of 140 nm.

<Production Examples of Silica Fine Particles 2 to 10>
In Silica Fine Particle Production Example 1, silica fine particles 2 to 10 were obtained in the same manner as in Silica Fine Particle Production Example 1, by adjusting the number average diameter of the primary particles by controlling the amounts and flow rates of the combustible gas and oxygen. Table 1 shows the particle size of the obtained silica fine particles.

[Example 1]
<Production Example of Toner 1>
Polyester resin 1: 100.0 parts Aluminum 3,5-di-t-butylsalicylate compound: 0.2 parts Fischer-Tropsch wax (maximum endothermic peak temperature: 90°C): 5.0 parts C.I. I. Pigment Blue 15:3 5.0 parts After mixing the above raw materials using a Henschel mixer (trade name: FM75J type, manufactured by Mitsui Miike Kakoki Co., Ltd.) at a rotation speed of 20 s-1 and a rotation time of 5 minutes , and kneaded with a twin-screw kneader (trade name: PCM-30 type, manufactured by Ikegai Co., Ltd.) set at a temperature of 125°C. The resulting kneaded product was cooled and coarsely pulverized to 1 mm or less with a hammer mill to obtain a coarsely pulverized product. The obtained coarsely crushed product was finely pulverized with a mechanical pulverizer (trade name: T-250, manufactured by Turbo Kogyo Co., Ltd.). The operating condition was a rotor speed of 10000 rpm. Further, classification was performed using Faculty (F-300, manufactured by Hosokawa Micron Corporation) to obtain toner particles 1. The operating conditions were a classification rotor rotation speed of 6000 rpm and a dispersion rotor rotation speed of 8000 rpm.

The obtained toner particles were divided into large particle size side and small particle size side using an inertial classification type elbow jet (manufactured by Nittetsu Mining Co., Ltd.). The operating conditions are a feed rate of 5 kg/hr, an F classification edge (fine particle classification edge) of 10 to 15 mm, and a G classification edge (coarse particle classification edge) of maximum and closed, and the toner particles are evenly divided into F and M. The particles on the small particle size side were labeled F1, and the particles on the large particle size side were labeled M1.
・Toner particles F1 100 parts ・External additive (silica fine particles 1) 3 parts ・Small particle size inorganic fine particles (fumed silica surface-treated with hexamethyldisilazane, median diameter (D50) based on the number of particles is 12 nm) 1 part Above The materials were mixed in a Henschel mixer (Model FM-75, manufactured by Mitsui Miike Kakoki Co., Ltd.) at a rotation speed of 1900 rpm for a rotation time of 10 minutes to obtain F toner.
・Toner particles M1 100 parts ・External additive (silica fine particles 2) 3 parts ・Small particle size inorganic fine particles (fumed silica surface-treated with hexamethyldisilazane, median diameter (D50) based on the number of particles is 12 nm) 1 part Above The materials were mixed in a Henschel mixer (Model FM-75, manufactured by Mitsui Miike Kakoki Co., Ltd.) at a rotation speed of 1900 rpm for a rotation time of 10 minutes to obtain M toner.

The obtained F toner and M toner were uniformly mixed and passed through an ultrasonic vibrating sieve with a mesh size of 43 μm to obtain Toner 1 . The number-based median diameter (D50) of Toner 1 was 4.5 μm, the span value was 0.5, the average circularity was 0.960, the HS was 112 nm, and the HS/HL was 1.2. Table 3 shows the physical properties of Toner 1.

The obtained Toner 1 had an endothermic peak derived from the wax component at 90° C. in the DSC curve obtained by differential scanning calorimetry.

The toner 1 and the magnetic carrier were mixed at 0.5 s-1 and 5 using a V-type mixer (trade name: V-10 type, Tokuju Seisakusho Co., Ltd.) so that the toner concentration was 7% by mass. minutes. The magnetic carrier used was magnetic ferrite carrier particles (number average particle diameter: 35 μm) surface-coated with an acrylic resin.

Two-component developer 1 was obtained as described above.

Using the two-component developer 1, the evaluation described later was performed. Table 4 shows the evaluation results.

[Examples 2 to 15, Comparative Examples 1 to 2]
<Production Examples of Toners 2 to 17>
The same operation as in the manufacturing example of toner 1 was performed except that the operating conditions of the mechanical pulverizer T-250, the operating conditions of Faculty F-300, and the type of external additive were changed as shown in Table 2. Toners 2-17 and two-component developers 2-17 were obtained. Table 3 shows the physical properties of toners 2 to 17.

Using the obtained two-component developers 2 to 17, the same evaluation as in Example 1 was performed. Table 4 shows the evaluation results.

Evaluation was performed using the two-component developer 1 described above.

As an image forming apparatus, a modified imageRUNNER ADVANCE C5560 digital commercial printing printer manufactured by Canon was used, and two-component developer 1 was put in the developing device at the black position. As modifications of the apparatus, the fixing temperature, process speed, DC voltage V _DC of the developer carrier, charging voltage V _D of the electrostatic latent image carrier, and laser power were changed so that they could be set freely. In the image output evaluation, an FFh image (solid image) having a desired image ratio is output, and V _DC , V _D and laser power are adjusted so that the toner amount of the FFh image is desired, and the evaluation described later is performed. did FFh is a value representing 256 gradations in hexadecimal; 00h is the 1st gradation (white background) of 256 gradations, and FFh is the 256th gradation (solid portion) of 256 gradations. .

After the endurance test, evaluation was performed according to the following evaluation methods, and the results are shown in Table 4.

[An endurance test]
Paper: GFC-081 (81.0 g/m ² )
(Canon Marketing Japan Inc.)
Evaluation image: 00h image Test environment: High temperature and high humidity environment (temperature 30 ° C./humidity 80% RH (hereinafter H/H))
Fixing temperature: 160°C
Process speed: 377mm/sec

100,000 sheets of the evaluation image were output and a durability test was conducted.

[Image Quality]
Paper: GFC-081 (81.0 g/m ² )
(Canon Marketing Japan Inc.)
Vcontrast: 300V
(Adjusted by the DC voltage V _DC of the developer carrier, the charging voltage V _D of the electrostatic latent image carrier, and the laser power)
Evaluation image: 1 dot, 1 space vertical line image placed on the above A4 paper Test environment: Normal temperature and normal humidity environment: temperature 23 ° C./humidity 50% RH (hereinafter "N/N")
Fixing temperature: 170°C
Process speed: 377mm/sec

The evaluation image was output to evaluate the image quality. The value of Blur (a numerical value representing how a line is blurred as defined by ISO13660) was used as an evaluation index of image quality. It was measured using a personal IAS (image analysis system) (manufactured by QEA). The obtained Blur value was evaluated according to the following evaluation criteria. It was judged that the effects of the present invention were obtained when C or higher was obtained.

(Evaluation criteria)
A: Blur value less than 35 μm (very excellent)
B: Blur value of 35 μm or more and less than 38 μm (excellent)
C: Blur value of 38 μm or more and less than 44 μm (no problem level)
D: Blur value of 44 μm or more (unacceptable)

[Developability]
Paper: GFC-081 (81.0 g/m ² )
(Canon Marketing Japan Inc.)
Vcontrast: 350V
(Adjusted by the DC voltage V _DC of the developer carrier, the charging voltage V _D of the electrostatic latent image carrier, and the laser power)
Evaluation image: Place a 2 cm x 5 cm image in the center of the above A4 paper.
Fixing temperature: 170°C
Process speed: 377mm/sec

The image for evaluation was output and the developability was evaluated. The value of image density was used as an evaluation index for developability. Using an X-Rite color reflection densitometer (500 series: manufactured by X-Rite), the image density at the center is measured. The obtained image density values were evaluated according to the following evaluation criteria. It was judged that the effects of the present invention were obtained for C or more.

(Evaluation criteria)
A: Image density value of 1.35 or more (extremely excellent)
B: Image density value of 1.30 or more and less than 1.35 (excellent)
C: Image density value of 1.25 or more and less than 1.30 (no problem level)
D: Image density value less than 1.25 (unacceptable)

[Fog resistance]
Paper: CS-680 (68.0 g/m ² )
(Canon Marketing Japan Inc.)
Evaluation image: 00h image on the entire surface of the above A4 paper Vback: 150V
(Adjusted by the DC voltage V _DC of the developer carrier, the charging voltage V _D of the electrostatic latent image carrier, and the laser power)
Test environment: High temperature and high humidity environment (Temperature 30°C / Humidity 80% RH (hereinafter H/H))
Fixing temperature: 170°C
Process speed: 377mm/sec

The image for evaluation was output to evaluate the anti-fogging property. The fog value was used as an evaluation index for anti-fogging. Using a reflectometer (REFECTOMETER MODEL TC-6DS: manufactured by Tokyo Denshoku), the average reflectance Ds (%) of the evaluation paper before passing is measured. Next, the average reflectance Dr (%) of the evaluation paper after passing is measured. Then, the fog value was calculated using the following formula. The obtained fog value was evaluated according to the following evaluation criteria. It was judged that the effects of the present invention were obtained for C or more.
Fog = Dr (%) - Ds (%)

(Evaluation criteria)
A: Less than 0.3% fog (excellent)
B: Fog 0.3% or more and less than 0.8% (excellent)
C: Fog 0.8% or more and less than 1.3% (no problem level)
D: Fog less than 1.3% (unacceptable)

[Member Contamination, Image Density Uniformity Evaluation]
Paper: GFC-081 (81.0 g/m ² )
(Canon Marketing Japan Inc.)
Vcontrast: 350V
(Adjusted by the DC voltage V _DC of the developer carrier, the charging voltage V _D of the electrostatic latent image carrier, and the laser power)
Evaluation image: 80 hours image on the entire surface of the A3 paper Test environment: Normal temperature and normal humidity environment: Temperature 23 ° C./humidity 50% RH (hereinafter "N/N")
Fixing temperature: 170°C
Process speed: 377mm/sec

The evaluation image was output to evaluate member contamination and image density uniformity. Before the durability evaluation, a solid image was output for 80 hours on the entire surface of A3 paper, and the average density of 6 points of the output image was set to ds. , the transfer current was set in the same manner as before the durability evaluation, the average density de of the output image at 6 points after the durability evaluation was measured, and the change in density was obtained from the following equation. Further, for the image density uniformity, the maximum and minimum values of 6 points of the output image after durability evaluation were obtained. It was judged that the effects of the present invention were obtained for C or more.
Density change = de-ds

<Member contamination evaluation criteria>
A: Density change less than 0.10 (very good)
B: Density change of 0.10 or more and less than 0.15 (excellent)
C: Density change is 0.15 or more and less than 0.25 (no problem level)
D: Density change of 0.25 or more (unacceptable in the present invention)

<Evaluation Criteria for Image Density Uniformity>
A: Density difference less than 0.05 (very good)
B: Density difference of 0.05 or more and less than 0.10 (excellent)
C: Density difference is 0.10 or more and less than 0.15 (no problem level)
D: Density difference of 0.15 or more (unacceptable in the present invention)

Claims (4)

Toner particles containing a binder resin and a colorant, and a toner containing an external additive,
the median diameter (D50) of the toner based on the number of particles is 3.0 μm or more and 6.0 μm or less;
With regard to the surface height of the toner particle surface due to the external additive, which is obtained by scanning electron microscopy (SEM) of the toner, the surface height of the toner having a particle size less than the median diameter (D50) is HS [nm]. A toner that satisfies the following formulas (1) and (2), where HL [nm] is the surface height of the toner having a particle diameter equal to or larger than the median diameter (D50).
61≤HS≤300 (1)
1.1≤HS/HL≤3.0 (2) 2. The toner according to claim 1, wherein the span value of the toner obtained by the following formula (3) is 0.7 or less.
Span value = (D90-D10)/D50 (3) 3. The toner according to claim 1, wherein the external additive is silica fine particles having a number-based average particle size of 80 nm or more and 300 nm or less. 4. The toner according to any one of claims 1 to 3, wherein the HS is 70 nm or more and 200 nm or less.