JP2007164082A - Non-magnetic one component toner - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a non-magnetic one component toner with which toner thin film formation on a developing roller is maintained even in printing for a long period, an electrostatic charge quantity is stabilized, and high-quality images of high density and satisfactory uniformity free of fogging are obtained, and the fusion to a blade and selective development are prevented, and to make the toner applicable appropriately even for a recycling cartridge in which a developing roller, regulating roller, supply roller, etc., are recycled. <P>SOLUTION: The non-magnetic one component toner is prepared by adding (A) 0.5 to 3 parts by weight inorganic oxide particles of volume resistivity 1×10<SP>5</SP>to 5×10<SP>7</SP>Ωcm and number average grain size 0.35 to 0.65 μm, (B) 0.3 to 3 parts by weight hydrophobic silica of average primary particle diameter ≥5 nm to <30 nm, and (C) 0.3 to 3 parts by weight hydrophobic silica of average primary particle diameter ≥30 nm to <80 nm to 100 parts by weight toner base particles. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a nonmagnetic one-component toner. More specifically, the present invention maintains the formation of a toner thin film on the developing roller even during long-term printing, stabilizes the charge amount, and provides a high-quality image with high density, good solid uniformity, and no fogging, The present invention relates to a non-magnetic one-component toner that can be suitably applied to a reproduction cartridge in which fusing to a blade and selective development are prevented, and in particular, a developing roller, a regulating blade, a supply roller, and the like are reused.

In the image forming method using the electrophotographic method, the photosensitive member is uniformly charged, and then the photosensitive member is exposed to dissipate the charge on the exposed portion to form an electrostatic latent image. The toner image is visualized and developed by adhering to the toner, the visualized image is transferred to a material such as paper, and the transferred image is fixed by means such as heating. Development methods include a one-component method using only one type of magnetic or non-magnetic toner and a two-component method using two types of powder, toner and carrier. The one-component development method can reduce the size and simplification of the apparatus. In particular, the non-magnetic one-component toner is characterized by vivid color toner.
In an image forming apparatus for non-magnetic one-component development, metal oxide such as hydrophobic silica, titanium oxide, alumina, tin oxide, etc. is used on the toner mother particles in order to make the charge amount of the toner on the developing roller uniform in long-term printing. And resin fine particles such as polymethyl methacrylate are added. In recent years, remanufactured cartridges have become widespread from the viewpoint of improving quality and protecting the global environment. However, in the case of reusing the developing roller, the regulating blade, the supply roller, etc., the reproduction cartridge has a problem that defective printing occurs due to deterioration of these members. For example, in the developing roller, the toner surface is deteriorated due to deterioration of the roller surface or contamination due to the toner-containing substance, causing solid image blurring or fogging due to charging failure. In the regulation blade, fogging due to poor charging of toner occurs due to wear of the contact portion with the developing roller. Further, in the case of a metal regulating blade, a metal crack is generated, and toner is fused to the blade starting from the crack. The material of the supply roller is often made of a sponge, and the surface of the sponge is damaged, and solid images are uneven due to defective supply of toner to the developing roller. Further, the peelability of undeveloped toner is lowered, the thickness of the toner layer is increased, resulting in poor charging, the torque of the developing roller is increased, and the worst situation of gear breakage may occur.
Various attempts have been made to modify the toner by adding inorganic fine particles to the toner base particles. For example, there is a fine particle carrying zinc oxide containing a different element on the surface of the base particle as a developer capable of efficiently starting up uniform triboelectric chargeability and achieving a high-quality image, and the mass ratio of Zn / base particle Is 0.01-2, the molar ratio of foreign element / Zn is 0.001-0.3, the volume average diameter is 0.1-5 μm, the number of particles having a particle diameter of 5 μm or more is less than 3% by number, and the resistance is 1 × 10 ^A developer having a resistance of ⁹ Ωcm or less has been proposed (Patent Document 1). In the embodiment, a magnetic one-component development system and a two-component development system are exemplified. However, when applied to non-magnetic one-component development, blade fusion may occur in long-term image printing.
Further, as a developing method of a one-component developer that does not decrease the image density even in long-term continuous printing and can reuse the collected toner, a thermoplastic resin having a volume resistivity of 1 × 10 ¹⁵ Ω · cm or more, a volume resistivity of 1 X10 ⁵ to 1 × 10 ¹² Ω · cm of charge stabilizer, colorant, volume resistivity 1 × 10 ⁵ to 1 × 10 ⁸ Ω · cm, average particle diameter of 0.05 to 1.0 μm A method using a one-component toner containing 0.05 to 5% by weight has been proposed (Patent Document 2). In this method, the charge amount is adjusted by toner charge leakage to stabilize the image density, but the embodiment only discloses printing results up to 500 sheets, and there is a problem in long-term image printing. Remains. In addition, when applied to a reproduction cartridge having deteriorated members, problems such as solid image unevenness, fogging, and blade fusion cannot be used.
As non-magnetic one-component developing toner that has low fog, excellent black solid reproducibility, and excellent transfer characteristics, alumina particles, hydrophobic silica particles having an Al ₂ O ₃ content of 90% by weight or more, and A nonmagnetic one-component developing toner in which magnetic powder is adhered to the surface of toner particles has been proposed (Patent Document 3). As its effect, improvement of image quality by stabilizing triboelectric charge of individual particles of toner is mentioned, but alumina is a specification of purity and particle size, and magnetite is a specification of only particle size, so blade fusion and long-term image printing Only the toner having a predetermined particle size is selectively developed, and the selective development in which the particle size distribution of the toner remaining in the toner hopper greatly changes during long-term printing occurs, and there is room for improvement as a non-magnetic one-component toner. Further, the above-mentioned problem cannot be remarkably used for the reproduction cartridge.
JP 2003-57872 A JP-A-6-175392 JP 2001-318486 A

  The present invention maintains the formation of a toner thin film on the developing roller even during long-term printing, stabilizes the charge amount, provides a high-quality image with high density, good solid uniformity, and no fogging. It is an object of the present invention to provide a non-magnetic one-component toner that can be suitably applied to a remanufactured cartridge that is prevented from being attached and selectively developed and in particular, a developing roller, a regulating blade, a supply roller, and the like are reused. .

As a result of intensive studies to solve the above problems, the present inventor has found that the toner base particles have a volume resistivity of 1 × 10 ^{5 to} 5 × 10 ⁷ Ω · cm and a number average particle size of 0.35 to 0.65 μm. By adding inorganic oxide particles, hydrophobic silica having a small average primary particle size, and hydrophobic silica having a large average primary particle size, stable and good images can be obtained even for long-term printing. As a result, the present invention has been completed based on this finding.
That is, the present invention
(1) Inorganic oxide particles 0 having a volume resistivity of 1 × 10 ^{5 to} 5 × 10 ⁷ Ω · cm and a number average particle size of 0.35 to 0.65 μm with respect to 100 parts by weight of toner base particles. 0.5 to 3 parts by weight, (B) 0.3 to 3 parts by weight of hydrophobic silica having an average primary particle size of 5 nm to less than 30 nm, and (C) 0.3 to 3 parts by weight of hydrophobic silica having an average primary particle size of 30 nm to less than 80 nm A non-magnetic one-component toner obtained by adding ˜3 parts by weight, and
(2) The nonmagnetic one-component toner according to (1), wherein the inorganic oxide particles are octahedral magnetite having an oil absorption of less than 25 mL / 100 g.
Is to provide.

  The non-magnetic one-component toner of the present invention comprises (A) inorganic oxide particles having a low volume resistivity, a number average particle size of 0.35 to 0.65 μm, and a small content of particles having a large particle size, (B It can be easily manufactured by adding hydrophobic silica having a small average primary particle size and (C) hydrophobic silica having a large average primary particle size to the toner base particles, and has low toner cohesion and good fluidity. Therefore, it is possible to obtain a high-quality printed image stably over a long period of time. The non-magnetic one-component toner of the present invention can be suitably applied to a remanufactured cartridge in which fusing to a roller, a blade, or the like is prevented, and a developing roller, a regulating blade, a supply roller, etc. are reused.

The non-magnetic one-component toner of the present invention has (A) volume resistivity of 1 × 10 ^{5 to} 5 × 10 ⁷ Ω · cm and a number average particle size of 0.35 to 0.65 μm with respect to 100 parts by weight of toner base particles. 0.5-3 parts by weight of inorganic oxide particles, (B) 0.3-3 parts by weight of hydrophobic silica having an average primary particle size of 5 nm or more and less than 30 nm, and (C) an average primary particle size of 30 nm or more and less than 80 nm Is a non-magnetic one-component toner obtained by adding 0.3 to 3 parts by weight of hydrophobic silica.
Examples of (A) inorganic oxide particles used in the present invention include aluminum oxide, magnesium oxide, calcium oxide, zinc oxide, tin oxide, copper oxide, iron oxide, cerium oxide, titanium oxide, barium titanate, and strontium titanate. And the like. Among these, iron oxide particles can be suitably used, magnetite can be more suitably used, and octahedral magnetite can be more suitably used. Octahedron magnetite has the lowest volume resistivity among magnetites, and the performance of non-magnetic one-component toner can be effectively improved by addition of a small amount. The magnetite used in the present invention preferably has an oil absorption of less than 25 mL / 100 g as measured with oil according to JIS K 5101. Magnetite having an oil absorption of less than 25 mL / 100 g has few aggregates and can be suitably used as an additive for non-magnetic one-component toner.

The (A) inorganic oxide particles used in the present invention have a volume resistivity of 1 × 10 ^{5 to} 5 × 10 ⁷ Ω · cm, more preferably 1 × 10 ^{6 to} 3 × 10 ⁷ Ω · cm. If the volume resistivity is less than 1 × 10 ⁵ Ω · cm, the charge amount of the toner particles may be reduced, and fogging may occur. When the volume resistivity exceeds 5 × 10 ⁷ Ω · cm, the increase in the charge amount cannot be suppressed in long-term printing, the supply roller is not sufficiently peelable, and the toner is not replaced. Blade fusion may occur, and the charged potential of the toner particles may become too high, resulting in a decrease in density and unevenness in the solid image.
In the present invention, the number average particle diameter of (A) inorganic oxide particles is a value determined for 50 inorganic oxide particles adhering to the surface of the toner particles observed with a scanning electron microscope (SEM). The inorganic oxide particles used in the present invention have a number average particle size of 0.35 to 0.65 μm, more preferably 0.45 to 0.60 μm. The average primary particle diameter of the inorganic oxide particles may be less than 0.35 μm, and is present on the toner surface in an aggregated state when externally added to the toner. The number average particle diameter at this time is 0.35 to 0.65 μm. I need it. If the number average particle diameter of the inorganic oxide particles is less than 0.35 μm, the particle diameter is too small to be a spacer between the toner particles, and frictional charging between the toner particles occurs, resulting in uneven charging and fogging. In addition, the adhesive force between the toner particles and the developing roller cannot be suppressed, and the peelability of the supply roller becomes insufficient, which may cause selective development and blade fusion. When the number average particle diameter of the inorganic oxide particles exceeds 0.65 μm, the inorganic oxide particles are easily released from the toner particles, and the effect of adding the inorganic oxide particles may not be sufficiently exhibited.

The inorganic oxide particles used in the present invention preferably contain less than 25% by number of particles having a particle size of 0.8 μm or more, and more preferably less than 22% by number. In the present invention, (A) the number% of inorganic oxide particles having a particle size of 0.8 μm or more is determined for 50 inorganic oxide particles adhering to the surface of the toner particles observed with a scanning electron microscope (SEM). Value. When the number of particles having a particle size of 0.8 μm or more is 25% by number or more, the amount of inorganic oxide particles released from the toner particles increases, and the effect of adding the inorganic oxide particles may not be sufficiently exhibited.
In the present invention, the amount of (A) inorganic oxide particles added is 0.5-3 parts by weight, more preferably 1-2 parts by weight, per 100 parts by weight of toner base particles. If the amount of the inorganic oxide particles added is less than 0.5 parts by weight based on 100 parts by weight of the toner base particles, the toner particles are insufficient as a spacer between the toner particles, resulting in frictional charging between the toner particles and uneven charging. May cause fogging. When the added amount of the inorganic oxide particles exceeds 3 parts by weight with respect to 100 parts by weight of the toner base particles, the surface of the photoreceptor is severely worn, the fluidity of the toner is deteriorated, and the conveyance to the developing roller becomes poor. There is a fear.
In the present invention, (A) inorganic oxide particles surface-treated with silicone oil or a silane coupling agent can be used as the inorganic oxide particles.

  In the non-magnetic one-component toner of the present invention, (B) hydrophobic silica having an average primary particle size of 5 nm or more and less than 30 nm, more preferably an average primary particle size of 7 nm or more and less than 20 nm, relative to 100 parts by weight of toner base particles. Add 3 to 3 parts by weight, more preferably 0.4 to 2 parts by weight. By adding hydrophobic silica having an average primary particle diameter of 5 nm or more and less than 30 nm to the toner base particles, the fluidity of the nonmagnetic one-component toner can be improved. If the average primary particle size of the hydrophobic silica is less than 5 nm, the hydrophobic silica is embedded in the toner base particles, and the fluidity improving effect may not be sufficiently exhibited. When the addition amount of hydrophobic silica having an average primary particle diameter of 5 nm or more and less than 30 nm is less than 0.3 part by weight with respect to 100 parts by weight of the toner base particles, the fluidity of the nonmagnetic one-component toner is not improved, and the developing roller There is a risk that the transport to the product becomes defective, and this tendency may be particularly noticeable in the reused product. If the added amount of hydrophobic silica having an average primary particle size of 5 nm or more and less than 30 nm exceeds 3 parts by weight with respect to 100 parts by weight of the toner base particles, the charged potential of the toner particles becomes too high, resulting in a decrease in density or unevenness in the solid image. May occur.

In the non-magnetic one-component toner of the present invention, (C) hydrophobic silica having an average primary particle diameter of 30 nm or more and less than 80 nm, more preferably an average primary particle diameter of 35 nm or more and less than 60 nm, relative to 100 parts by weight of toner mother particles. Add 3 to 3 parts by weight, more preferably 0.6 to 2 parts by weight. By adding hydrophobic silica having an average primary particle diameter of 30 nm or more and less than 80 nm to the toner base particles, embedding of the hydrophobic silica in the toner base particles can be prevented, and good image quality can be obtained even in long-term repeated image formation. It is done. When the average primary particle diameter of the hydrophobic silica exceeds 80 nm, the hydrophobic silica is liberated from the toner base particles, and the durability improving effect may not be sufficiently exhibited. When the addition amount of hydrophobic silica having an average primary particle size of 30 nm or more and less than 80 nm is less than 0.3 parts by weight with respect to 100 parts by weight of the toner base particles, durability is not improved and blade fusion is likely to occur. There is a fear. If the added amount of hydrophobic silica having an average primary particle size of 30 nm or more and less than 80 nm exceeds 3 parts by weight with respect to 100 parts by weight of the toner base particles, the fluidity of the nonmagnetic one-component toner may be lowered.
In the present invention, when only hydrophobic silica (B) having an average primary particle diameter of 5 nm or more and less than 30 nm is added as hydrophobic silica, embedding of hydrophobic silica in toner base particles cannot be prevented, and long-term repeated image formation In this case, stable image quality cannot be obtained, and blade fusion may occur easily. In the present invention, if only (C) hydrophobic silica having an average primary particle diameter of 30 nm or more and less than 80 nm is added as the hydrophobic silica, the fluidity of the non-magnetic one-component toner may be lowered.

There is no restriction | limiting in particular in the manufacturing method of the silica used for this invention, For example, any of dry method silica, wet precipitation method silica, wet gel method silica, etc. can be used. The hydrophobic silica used in the present invention can be produced by surface-treating these silicas using a silane coupling agent, silicone oil or the like. Examples of the silane coupling agent include amine functional silanes such as hexamethyldisilazane and triethylaminosilane, epoxy functional silanes such as (3-glycidyloxypropyl) trimethoxysilane, and mercapto functional silanes such as 3-mercaptopropyltrimethoxysilane. And so on.
There are no particular restrictions on the method for producing toner base particles used in the present invention. For example, a binder resin, a colorant, a charge control agent, a release agent, etc. are melt-kneaded, pulverized, and coarse particles and fine particles are removed by classification. The particle size distribution can be narrowed to obtain toner base particles. Examples of the binder resin include polyester resins, polyurethane resins, polyolefin resins, styrene- (meth) acrylate copolymers, polyamide resins, acrylic resins, ketone resins, maleic resins, coumarone resins, phenols. Examples thereof include resins, epoxy resins, terpene resins, petroleum resins, polystyrene, styrene-butadiene copolymers, and styrene-maleic acid copolymers. The binder resin used in the method of the present invention preferably has a glass transition temperature of 50 to 75 ° C, more preferably 55 to 70 ° C. If the glass transition temperature is less than 50 ° C., the storage stability of the non-magnetic one-component toner may be reduced. If the glass transition temperature exceeds 75 ° C, the low-temperature fixability of the non-magnetic one-component toner may be insufficient. Examples of the colorant include carbon black, triiron tetroxide, permanent yellow, quinacridone, copper phthalocyanine, and the like. Examples of charge control agents include negatively chargeable charge control agents such as acetylacetone metal compounds, aromatic hydroxycarboxylic acids, monoazo metal compounds, metal-containing salicylic acid compounds, triphenylmethane dyes, nigrosine, quaternary ammonium salts, and the like. A positively chargeable charge control agent can be used. Examples of the mold release agent include carnauba wax, paraffin wax, montan wax, polyethylene wax, polypropylene wax, and ester wax.

In the present invention, there is no particular limitation on the method of melt-kneading the binder resin, colorant, charge control agent, release agent, etc. For example, these materials can be mixed into a ribbon mixer, a double cone mixer, a high speed mixer. Then, after mixing in advance using a conical screw mixer or the like, it can be melt-kneaded using a Banbury mixer, a twin-screw kneading extruder, three rolls, or the like. The melt-kneaded product is pulverized after cooling. Examples of the pulverizer used include impact pulverizers such as impact crushers and hammer crushers, impact pulverizers such as rod mills and ball mills, and jet pulverizers using a compressed air source such as a counter jet mill. it can. The pulverized particles are preferably classified into toner particles having a narrow particle size distribution by removing coarse particles and fine particles. There is no restriction | limiting in particular in the classification method, For example, it can classify | categorize using an airflow classifier etc.
In the present invention, (A) inorganic oxide particles, (B) hydrophobic silica having an average primary particle diameter of 5 nm or more and less than 30 nm, and (C) hydrophobic silica having an average primary particle diameter of 30 nm or more and less than 80 nm are added to the toner base particles. The mixing method is not particularly limited. For example, a horizontal cylindrical mixer, a V-type mixer with stirring blades, a double cone type mixer, a vibratory rotary type mixer, a short axis ribbon type mixer, a double axis paddle type Mixer, rotary saddle type mixer, twin-shaft planetary stirring type mixer, conical screw type mixer, high speed stirring type mixer, rotary disk type mixer, rotary container type mixer with roller, rotary container type mixer with stirring These can be added and mixed using a high-speed elliptical rotor type mixer, an air-flow stirring type mixer, a non-stirring type mixer, or the like. Among these, it is preferable to mix at a peripheral speed of 30 m / s or more with a high-speed stirring mixer [Mitsui Mining Co., Ltd., Henschel Mixer (registered trademark)]. To the toner base particles, (A) inorganic oxide particles, (B) hydrophobic silica having an average primary particle diameter of 5 nm or more and less than 30 nm, and (C) hydrophobic silica having an average primary particle diameter of 30 nm or more and less than 80 nm are added and mixed. As a result, the two types of hydrophobic silica having different average primary particle diameters from the inorganic oxide particles adhere to the surface of the toner base particles.
The non-magnetic one-component developing toner of the present invention maintains the toner thin film formation on the developing roller even during long-term printing, stabilizes the charge amount, has high density, good solid uniformity, no fog, Fusing and selective development are prevented. The non-magnetic one-component toner of the present invention can provide good image quality even when a developing roller, a regulating blade, and a supply roller are reused, particularly in a reproduction cartridge.

Hereinafter, the present invention will be described in more detail with reference to examples, but the present invention is not limited to these examples.
In the examples, the evaluation was performed by the following method.
(1) Softening temperature of binder resin Using a capillary rheometer specified by JIS K 7199 (Shimadzu Corporation, CFT-500C), the inner diameter of the cylinder is 11.329 mm, the inner diameter of the capillary die is 1 mm, and the length is 1 mm. 1.0 g is charged, a load of 98 N is applied to the piston, the temperature is raised from 50 ° C. to 5 ° C./min, and the temperature when half of the filled resin flows out is defined as a flow tester T _1/2 . .
(2) Oil absorption amount According to JIS K 5101, the oil absorption is measured using oil.
(3) Volume resistivity of externally added inorganic oxide 1.0 g of toner is filled in a cylindrical container with a diameter of 1.29 mm, both ends of which are made of metal, and after tapping three times, a voltage of 100 V is applied. To measure.
(4) Particle diameter of inorganic oxide on the toner particle surface The particle diameter of 50 inorganic oxides adhering to the toner surface was examined with a scanning electron microscope [JEOL Ltd., JSM-5200]. The ratio of particles of 0.8 μm or more is obtained.
(5) Agglomeration degree of toner Using a powder tester [Hosokawa Micron Co., Ltd.], 100 mesh, 200 mesh, and 440 mesh sieves are stacked in three stages, and 5 g of toner is placed on the uppermost 100 mesh sieve. After vibrating for 2 seconds, the toner weight on each sieve is measured, and the degree of aggregation is calculated by the following equation.
Aggregation degree (%) = {[5 × (100 mesh remaining amount) + 3 × (200 mesh remaining amount) + (440 mesh remaining amount)] / (5 × 5)} × 100
(6) Image density Measured using a Macbeth densitometer [Macbeth, RD-19].
○: 1.11 or higher (good)
Δ: 1.05 or more and less than 1.11 (no problem in practical use)
×: Less than 1.05 (defect)
(7) Solid uniformity Determined by visual inspection.
○: No shading (good)
Δ: Contrast is confirmed when a solid print image is viewed through (no problem in practice)
X: The density is clearly confirmed (defect)
(8) Fog According to JIS P8152, the reflectance of the unused paper and the reflectance of the white background of the image are measured using a color difference meter [Minolta Co., Ltd.], and the difference is obtained.
○: Less than 1.0% (good)
Δ: 1.0% or more and less than 2.0% (no problem in practical use)
×: 2.0% or more (defect)
(9) Toner consumption Amount of toner used is calculated from the weight difference of the cartridge developer unit before and after the print test, printed on 6,000 sheets of A4 size paper at a print rate of 5%. Divide.
○: Less than 26 mg / sheet (good)
Δ: 26 mg / sheet or more and less than 29 mg / sheet (no problem in practical use)
×: 29 mg / sheet or more (defect)
(10) Blade fusion The white lines on the image are visually observed, and the number of print sheets until the vertical lines are generated is recorded. Also, after the evaluation is completed, the doctor blade is observed to check for the presence or absence of a fused product (fixed product) of the toner. If there is a fused product, it is confirmed whether it matches the position of the white spot on the image.
(11) Toner transport amount on the developing roller The toner on the developing roller is collected with a 1 cm × 5 cm mending tape [manufactured by Nichiban], the toner weight is measured, and the measured value is divided by 5 cm ² to obtain a unit area. The amount of toner transport per hit is calculated.
(12) Selective development The volume average particle diameter of the toner before printing test and after printing 6,000 sheets was measured using an aperture tube with an aperture diameter of 100 μm using Coulter Multisizer II [Coulter, Inc.], before and after the test. The difference of the volume average particle diameter of is evaluated.
○: Difference in volume average particle size of less than 1.0 μm (good)
Δ: Volume average particle size difference of 1.0 μm or more and less than 2.0 μm (no problem in practical use)
X: Difference in volume average particle diameter of 2.0 μm or more (practical problem due to increased toner consumption and solid uniformity deterioration)

Example 1
Polyester resin [number average molecular weight 4,000, weight average molecular weight 206,000, acid value 5.5 mg KOH / g, glass transition temperature 61 ° C., flow tester T _1/2 136 ° C.] 91.6 parts by weight, carbon black [Cabot Company, Black Pearls L] 5.0 parts by weight, charge control agent [Orient Chemical Industries, Ltd., E-304] 0.9 parts by weight and mold release agent [Sanyo Chemical Industries, Ltd., Umex 110TS] 2.5 Part by weight was previously mixed using a high-speed stirring mixer [Mitsui Mining Co., Ltd., Henschel Mixer (registered trademark)], and the resulting mixture was mixed at 150 ° C. using a twin-screw extruder [Ikegai, PCM30]. After being melt-kneaded with a jet type crusher [Hosokawa Micron Co., Ltd., counter jet mill], it is pulverized to a volume average particle size of 9 μm, and an airflow classifier [Nippon Mining Co., Ltd., Elbow Jet EJ-PURO]. Classified coarse powder and fine powder using a particle size distribution was obtained narrow toner mother particles.
100 parts by weight of the toner base particles, octahedral magnetite [volume resistivity 1.4 × 10 ⁷ Ω · cm, oil absorption 19.2 mL / 100 g] 1.5 parts by weight, hydrophobic silica [Cabot, TS-530, Average primary particle size 7 nm, hydrophobized with hexamethyldisilazane] 0.5 parts by weight and hydrophobic silica [Nippon Aerosil Co., Ltd., RX-50, average primary particle size 40 nm, hydrophobized with hexamethyldisilazane] 1.0 part by weight is mixed with a Henschel mixer [Mitsui Mining Co., Ltd.] at a rotational speed equivalent to a peripheral speed of 40 m / s, and further passed through an ultrasonic vibrating screen equipped with a 200 mesh screen to obtain non-magnetic one-component toner. Obtained.
When the particle size of octahedral magnetite on the surface of the toner particles was observed using a scanning electron microscope [JEOL Ltd., JSM-5200], the number average particle size was 0.55 μm, and the particle size was 0.8 μm or more. The number of particles was 20%. The degree of aggregation of the toner was 27.7%.
Using a non-magnetic one-component development type laser printer [Samsung, ML-2150], first, three continuous printing of an image pattern with a printing rate of 5% and a pause for 30 seconds are repeated with a genuine cartridge on an A4 size sheet 3 After printing 6,000 sheets in intermittent sheet mode, disassemble, clean and reassemble the cartridge, fill with 220 g of the above-mentioned non-magnetic one-component toner, print in intermittent mode with three sheets, and the initial 3,000 sheet And the evaluation was performed on the 6,000th sheet.
The image density was 1.52 at the initial stage, 1.54 for the 3,000th sheet, and 1.50 for the 6,000th sheet. The solid uniformity was good at the initial stage and the 3,000th sheet, and the 6,000th sheet was slightly poor although it was at a level of no practical problem. The fog was 0.42% at the initial stage, 0.39% at the 3,000th sheet, and 0.77% at the 6,000th sheet. The toner consumption was 25.4 mg / sheet. There were no white vertical stripes on the image, and no blade fusion occurred. Toner conveyance amount on the developing roller, the initial 0.66 mg / cm ^2, 3,000 sheet 0.62 mg / cm ^2, was 6,000 sheet 0.66 mg / cm ^2. The volume average particle diameter of the toner particles was 9.2 μm before the start of the print test and 10.1 μm after the end of the print test of 6,000 sheets.

Comparative Example 1
A non-magnetic one-component toner is produced in the same manner as in Example 1 except that 1.5 parts by weight of barium titanate [volume resistivity 1.0 × 10 ⁸ Ω · cm] is blended in place of octahedral magnetite. Then, a printing test was conducted.
When the particle size of barium titanate on the surface of the toner particles was observed using a scanning electron microscope, the number average particle size was 0.70 μm, and the number of particles having a particle size of 0.8 μm or more was 27% by number. The degree of aggregation of the toner was 37.9%.
In the printing test, blade fusion occurred on the 2,000th sheet, so the test was stopped. Initially, the image density is 1.54, the solid uniformity is good, the fog is 0.31%, the toner consumption up to 2,000 sheets is 24.5 mg / sheet, and the toner conveyance amount on the developing roller is 0.60 mg. / Cm ² .
Comparative Example 2
A non-magnetic one-component toner is produced in the same manner as in Example 1 except that 1.5 parts by weight of barium titanate [volume resistivity 1.2 × 10 ⁹ Ω · cm] is blended instead of octahedral magnetite. Then, a printing test was conducted.
When the particle diameter of barium titanate on the surface of the toner particles was observed using a scanning electron microscope, the number average particle diameter was 0.60 μm, and the number of particles having a particle diameter of 0.8 μm or more was 10% by number. The degree of aggregation of the toner was 44.6%.
The image density was 1.54 at the initial stage, 1.53 for the 3,000th sheet, and 1.51 for the 6,000th sheet. The solid uniformity was good in the initial stage, and the 3,000th sheet was slightly defective although it was a level that was not problematic for practical use, and the 6,000th sheet was unsatisfactory. The fog was 0.53% at the initial stage, 0.556% at the 3,000th sheet, and 0.80% at the 6,000th sheet. The toner consumption was 24.1 mg / sheet. There were no white vertical stripes on the image, and no blade fusion occurred. Toner conveyance amount on the developing roller, the initial 0.64 mg / cm ^2, 3,000 sheet 0.74 mg / cm ^2, was 6,000 sheet 0.76 mg / cm ^2. The volume average particle size of the toner particles was 9.1 μm before the start of the print test and 10.8 μm after the end of the print test of 6,000 sheets.

Comparative Example 3
Example 1 except that 1.5 parts by weight of spherical magnetite [volume resistivity 4.3 × 10 ¹⁰ Ω · cm, oil absorption 17.0 mL / g, surface treatment with silicone oil] was blended as inorganic oxide particles. In the same manner as above, a non-magnetic one-component toner was manufactured and a printing test was conducted.
When the particle size of the spherical magnetite on the surface of the toner particles was observed using a scanning electron microscope, the number average particle size was 0.20 μm and the number of particles having a particle size of 0.8 μm or more was 5% by number. The degree of aggregation of the toner was 35.2%.
In the printing test, fogging was intense from the beginning, and even the 250th sheet was not good, so the test was stopped. Initially, the image density was 1.44, the solid uniformity was at a level that was not a problem for practical use, but was slightly poor, the fog was 2.17%, and the toner conveyance amount on the developing roller was 0.64 mg / cm ² .
Comparative Example 4
As inorganic oxide particles, except for blending 3.0 parts by weight of amorphous magnetite [Titanium Industry Co., Ltd., RB-BL, volume resistivity 1.0 × 10 ⁶ Ω · cm, oil absorption 19.0 mL / g] In the same manner as in Example 1, a nonmagnetic one-component toner was produced and a printing test was conducted.
When the particle size of the irregular magnetite on the surface of the toner particles was observed using a scanning electron microscope, the number average particle size was 0.80 μm, and the number of particles having a particle size of 0.8 μm or more was 50% by number. The degree of aggregation of the toner was 39.6%.
In the printing test, blade fusion occurred on the 5,000th sheet, but the test was continued up to the 6,000th sheet. The image density was 1.46 for the initial and 3,000th sheets and 1.27 for the 6,000th sheet. The solid uniformity was good in the initial stage, and the 3,000th sheet was slightly defective although it was a level that was not problematic for practical use, and the 6,000th sheet was unsatisfactory. The fog was 0.82% at the initial stage, 0.76% at the 3,000th sheet, and 1.39% at the 6,000th sheet. The toner consumption was 30.2 mg / sheet. Toner conveyance amount on the developing roller, the initial 0.54 mg / cm ^2, 3,000 sheet 0.60 mg / cm ^2, was 6,000 sheet 0.72 mg / cm ^2. The volume average particle diameter of the toner particles was 9.2 μm before the start of the print test and 12.5 μm after the end of the print test of 6,000 sheets.
Comparative Example 5
A nonmagnetic one-component toner was produced in the same manner as in Example 1 except that 1.5 parts by weight of titanium oxide [volume resistivity 1.2 × 10 ⁶ Ω · cm] was blended as inorganic oxide particles. A printing test was conducted.
When the particle size of titanium oxide on the surface of the toner particles was observed using a scanning electron microscope, the number average particle size was 0.30 μm, and the number of particles having a particle size of 0.8 μm or more was 7% by number. The degree of aggregation of the toner was 25.7%.
In the printing test, blade fusion occurred on the 3,000th sheet, so the test was stopped. The image density was 1.51 at the initial stage and 1.52 at the 3000th sheet. The solid uniformity was good in the initial stage, and the 3,000th sheet was slightly poor although it was at a level where there was no practical problem. The fog was 0.63% at the initial stage and 0.71% at the 3000th sheet. The toner consumption up to 3,000 sheets was 29.4 mg / sheet. Toner conveyance amount on the developing roller, the initial 0.60 mg / cm ^2, was 3,000 sheet 0.66 mg / cm ^2.

Comparative Example 6
To 100 parts by weight of the toner base particles prepared in Example 1, 1.5 parts by weight of octahedral magnetite [volume resistivity 1.4 × 10 ⁷ Ω · cm, oil absorption 19.2 mL / 100 g] and hydrophobic silica [Cabot TS-530, average primary particle diameter 7 nm, hydrophobized with hexamethyldisilazane] A non-magnetic one-component toner was produced and printed in the same manner as in Example 1 except that 1.5 parts by weight were blended. A test was conducted.
When the particle size of octahedral magnetite on the surface of the toner particles was observed using a scanning electron microscope, the number average particle size was 0.55 μm, and the number of particles having a particle size of 0.8 μm or more was 20% by number. The degree of aggregation of the toner was 21.0%.
In the printing test, blade fusion occurred at the 1,000th sheet, so the test was stopped. The initial image density was 1.53. The solid uniformity was good initially, and the fog was 0.59% initially. The toner conveyance amount on the developing roller was initially 0.64 mg / cm ² .
Comparative Example 7
To 100 parts by weight of toner base particles prepared in Example 1, 1.5 parts by weight of octahedral magnetite [volume resistivity 1.4 × 10 ⁷ Ω · cm, oil absorption 19.2 mL / 100 g] and hydrophobic silica [Japan Aerosil Co., Ltd., RX-50, average primary particle size 40 nm, hydrophobized with hexamethyldisilazane] A non-magnetic one-component toner is produced in the same manner as in Example 1 except that 1.5 parts by weight is blended. Then, a printing test was conducted.
When the particle size of octahedral magnetite on the surface of the toner particles was observed using a scanning electron microscope, the number average particle size was 0.55 μm, and the number of particles having a particle size of 0.8 μm or more was 20% by number. The degree of aggregation of the toner was 48.2%.
The image density was 1.41 at the initial stage, 1.36th at the 3,000th sheet, and 1.17 at the 6,000th sheet. The solid uniformity was at a level where there was no practical problem in the initial stage, and the 3,000th and 6,000th sheets were poor. The fog was 0.22% at the initial stage, 0.38% at the 3,000th sheet, and 0.34% at the 6,000th sheet. The toner consumption was 19.6 mg / sheet. Blade fusion did not occur. Toner conveyance amount on the developing roller, the initial 0.44 mg / cm ^2, 3,000 sheet 0.38 mg / cm ^2, was 6,000 sheet 0.34 mg / cm ^2. The volume average particle diameter of the toner particles was 9.1 μm before the start of the print test and 10.6 μm after the end of the print test of 6,000 sheets.
Table 1 shows the properties and addition amounts of the inorganic oxide and hydrophobic silica of Example 1 and Comparative Examples 1 to 7, and Table 2 shows the test results of the obtained nonmagnetic one-component toner.

As seen in Tables 1 and 2, 100 parts by weight of the toner base particles are particles having a volume resistivity of 1.4 × 10 ⁷ Ω · cm, a number average particle size of 0.55 μm, and a particle size of 0.8 μm or more. Example 1 in which 1.5 parts by weight of 20% by number of octahedral magnetite, 0.5 parts by weight of hydrophobic silica having an average primary particle diameter of 7 nm and 1.0 part by weight of hydrophobic silica having an average primary particle diameter of 40 nm were added. The magnetic one-component toner has a low degree of aggregation and is stable at an image density of 1.50 to 1.54 in a print test of 6,000 sheets. The solid uniformity is good up to 3,000 sheets. Even on a sheet, the level is practically acceptable, fog does not occur, toner consumption is small, blade fusion does not occur, toner conveyance amount is stable at 0.62 to 0.66 mg / cm ² , The increase in volume average particle size after printing 000 sheets is 0.9 μm.
On the other hand, instead of octahedral magnetite, barium titanate having a volume resistivity of 1.0 × 10 ⁸ Ω · cm, a number average particle size of 0.70 μm, and 27% by number of particles having a particle size of 0.8 μm or more is added. The nonmagnetic one-component toner of Comparative Example 1 has a high toner aggregation degree, and blade fusion occurs on 2,000 sheets. The non-magnetic one-component toner of Comparative Example 2 to which barium titanate having a volume resistivity of 1.2 × 10 ⁹ Ω · cm is added has a large toner aggregation degree, and as the number of printed sheets increases, the solid uniformity decreases and the toner conveyance The amount increases and the increase of the volume average particle size after printing 6,000 sheets is slightly large as 1.7 μm.
The non-magnetic one-component toner of Comparative Example 3 to which spherical magnetite having a volume resistivity of 4.3 × 10 ¹⁰ Ω · cm and a number average particle size of 0.20 μm is added as the inorganic oxide particles has a large toner aggregation degree and printing. Initial fog is occurring. The non-magnetic one-component toner of Comparative Example 4 to which 50% by number of amorphous magnetite having a volume average particle size of 0.80 μm and a particle size of 0.8 μm or more is added has a high toner aggregation degree, a low image density, and the number of printed sheets. As the toner content increases, the solid uniformity decreases, the toner conveyance amount increases, the toner consumption is large, blade fusion occurs at 5,000 sheets, and the increase in volume average particle diameter after printing 6,000 sheets is 3 .3 μm and large. In the nonmagnetic monocomponent toner of Comparative Example 5 to which titanium oxide having a volume average particle size of 0.30 μm was added, blade fusion occurred on 3,000 sheets.
The non-magnetic one-component toner of Comparative Example 6 to which only hydrophobic silica having an average primary particle diameter of 7 nm is added as hydrophobic silica has good initial density and fog, but blade fusion occurs with 1,000 sheets. Therefore, the test was stopped. The nonmagnetic one-component toner of Comparative Example 7 to which only hydrophobic silica having an average primary particle size of 40 nm is added has poor fluidity, insufficient toner conveyance on the developing roller from the beginning, and low density and solid uniformity are poor. This is the result.

  The non-magnetic one-component toner of the present invention comprises (A) inorganic oxide particles having a low volume resistivity, a number average particle size of 0.35 to 0.65 μm, and a small content of particles having a large particle size, (B It can be easily manufactured by adding hydrophobic silica having a small average primary particle size and (C) hydrophobic silica having a large average primary particle size to the toner base particles, and has low toner cohesion and good fluidity. Therefore, it is possible to obtain a high-quality printed image stably over a long period of time. The non-magnetic one-component toner of the present invention can be suitably applied to a remanufactured cartridge in which fusing to a roller, a blade, or the like is prevented, and a developing roller, a regulating blade, a supply roller, etc. are reused.

Claims (2)

(A) Inorganic oxide particles having a volume resistivity of 1 × 10 ^{5 to} 5 × 10 ⁷ Ω · cm and a number average particle size of 0.35 to 0.65 μm with respect to 100 parts by weight of toner mother particles 0.5 to 3 parts by weight, (B) 0.3-3 parts by weight of hydrophobic silica having an average primary particle diameter of 5 nm or more and less than 30 nm, and (C) 0.3-3 parts by weight of hydrophobic silica having an average primary particle diameter of 30 nm or more and less than 80 nm A non-magnetic one-component toner obtained by adding a part.   The non-magnetic one-component toner according to claim 1, wherein the inorganic oxide particles are octahedral magnetite having an oil absorption of less than 25 mL / 100 g.