Classifications

• • C—CHEMISTRY; METALLURGY
  • C01—INORGANIC CHEMISTRY
  • C01B—NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C
  • C01B33/00—Silicon; Compounds thereof
  • C01B33/113—Silicon oxides; Hydrates thereof
  • C01B33/12—Silica; Hydrates thereof, e.g. lepidoic silicic acid
  • C01B33/18—Preparation of finely divided silica neither in sol nor in gel form; After-treatment thereof
• • G—PHYSICS
  • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
  • G03G—ELECTROGRAPHY; ELECTROPHOTOGRAPHY; MAGNETOGRAPHY
  • G03G9/00—Developers
  • G03G9/08—Developers with toner particles
  • G03G9/097—Plasticisers; Charge controlling agents
  • G03G9/09708—Inorganic compounds
  • G03G9/09725—Silicon-oxides; Silicates
• • C—CHEMISTRY; METALLURGY
  • C01—INORGANIC CHEMISTRY
  • C01P—INDEXING SCHEME RELATING TO STRUCTURAL AND PHYSICAL ASPECTS OF SOLID INORGANIC COMPOUNDS
  • C01P2004/00—Particle morphology
  • C01P2004/30—Particle morphology extending in three dimensions
  • C01P2004/32—Spheres
• • C—CHEMISTRY; METALLURGY
  • C01—INORGANIC CHEMISTRY
  • C01P—INDEXING SCHEME RELATING TO STRUCTURAL AND PHYSICAL ASPECTS OF SOLID INORGANIC COMPOUNDS
  • C01P2006/00—Physical properties of inorganic compounds
  • C01P2006/11—Powder tap density

Definitions

• the present invention relates to a hydrophobized spherical silica fine powder, a production method thereof and use thereof.
• silica fine powder has been used as an external additive to improve fluidity and stabilize charging characteristics. ing.
• the characteristics required for this silica fine powder are that it has high hydrophobicity in order to reduce the change in charge amount due to humidity, and that the toner surface can be uniformly coated and that there is little aggregation and high dispersion.
• the specific surface area of the silica fine powder an ultrafine powder of about 200 to 500 m 2 / g is used, but as the image is repeatedly formed, the silica ultrafine powder is embedded in the toner particle surface, and the toner It has been confirmed that the fluidity, triboelectric charge amount, transferability, and the like of the toner deteriorate and cause image defects.
• Patent Document 1 Patent Document 2
• Patent Document 2 Patent Document 2
• inorganic fine powder having a specific surface area of less than 80 m 2 / g and a relatively large particle diameter is used in combination.
• An inorganic fine powder having a relatively large particle size exhibits a spacer effect that reduces stress caused by direct contact between toners. In this way, a method of suppressing the burying of the ultrafine silica powder and extending the life of the toner is taken.
• Patent Document 3 In the fluidity of the toner, if the amount of the inorganic fine powder having a relatively large particle size is increased, the fluidity is deteriorated.
• Patent Document 3 a method in which 20 to 100 m 2 / g of fumed silica is surface-treated in the presence of an amine catalyst using an alkylalkoxysilane having a hexyl group or less.
• externally added charge control particles obtained by applying a charge control agent to hydrophobic spherical silica fine particles of 20 to 500 nm obtained by hydrophobizing hydrophilic spherical silica fine particles obtained by the sol-gel method have a triboelectric charge amount.
• Patent Document 4 It has been proposed (Patent Document 4) as a method of keeping a certain range.
• Patent Document 1 the inorganic fine powder having a relatively large particle size tends to have a smaller charge amount than the ultrafine powder, and the external addition amount is increased in order to improve the spacer effect. As a result, the charge amount decreases.
• Patent Document 3 if the amount of external addition is increased due to the shape of fumed silica and aggregation due to alkylsilane, the fluidity may be deteriorated.
• Patent Document 4 it cannot be said that the spacer effect for reducing the stress caused by direct contact between toners is sufficient, and the charge amount may decrease due to the removal of the charge control agent due to repeated use.
• An object of the present invention is to provide a hydrophobized spherical silica fine powder suitable for producing a toner external additive excellent in charge stability, fluidity, spacer effect and charge amount.
• the present inventor has intensively studied to achieve the above object, and has succeeded in controlling the powder resistance, the water content, and the tap density, and has found a hydrophobized spherical silica fine powder that achieves this.
• the present invention is based on such knowledge, and the present invention employs the following means (1) in order to solve the above-mentioned problems.
• the powder resistance is 1.0 ⁇ 10 13 ⁇ ⁇ cm or more and 3.0 ⁇ 10 14 ⁇ ⁇ cm or less
• the water content is 0.5 wt% or less
• the tap density is 0.10 g / cm 3.
• a hydrophobized spherical silica fine powder characterized by being 0.40 g / cm 3 or more.
• the following means are employed.
• the average particle size of the hydrophobized spherical silica fine powder measured by a laser diffraction / scattering particle size distribution analyzer is 0.080 ⁇ m or more and 0.200 ⁇ m or less, and the maximum particle size of the hydrophobized spherical silica fine powder
• the spherical silica fine powder has a water content of 0.4 wt% or less, an average particle size measured by a laser diffraction / scattering particle size distribution analyzer of 0.070 ⁇ m to 0.170 ⁇ m, and the maximum
• a toner external additive for developing an electrostatic charge image comprising the hydrophobized spherical silica fine powder described in any one of (1) to (3) above.
• a hydrophobic spherical silica fine powder suitable for producing a toner external additive excellent in charge stability, fluidity, spacer effect, and charge amount is provided.
• the hydrophobized spherical silica fine powder needs to have a powder resistance of 1.0 ⁇ 10 13 ⁇ ⁇ cm or more and 3.0 ⁇ 10 14 ⁇ ⁇ cm or less.
• the powder resistance is less than 1.0 ⁇ 10 13 ⁇ ⁇ cm, the charge amount becomes small, and there is a problem that the toner charge amount decreases when used as an external toner additive.
• Preferable powder resistance is 1.5 ⁇ 10 13 ⁇ ⁇ cm or more and 2.5 ⁇ 10 14 ⁇ ⁇ cm or less, and more preferably 2.0 ⁇ 10 13 ⁇ ⁇ cm or more and 2.0 ⁇ 10 14 ⁇ ⁇ cm or less. It is.
• the powder resistance is, for example, 1.5 ⁇ 10 13 , 1.6 ⁇ 10 13 , 2.0 ⁇ 10 13 , 5.0 ⁇ 10 13 , 1.0 ⁇ 10 14 , 1.9 ⁇ 10 14 , 2.0 ⁇ 10 14 , 2.1 ⁇ 10 14 , 2.5 It may be ⁇ 10 14 , 2.9 ⁇ 10 14 , or 3.0 ⁇ 10 14 ⁇ ⁇ cm, and may be within the range of any two of them.
• the powder resistance of the hydrophobized spherical silica fine powder can be measured using “Powder Resistance Measurement System MCP-PD51, 4-probe probe” manufactured by Mitsubishi Chemical Analytech. After 2.0 g of hydrophobized spherical silica powder was allowed to stand for 24 hours under conditions of a temperature of 25 ° C. and a relative humidity of 55%, it was filled in a measurement mold of ⁇ 20 mm and measured under a pressure of 38.2 MPa. The applied voltage was 1000 V and the voltage application time was 20 seconds.
• the hydrophobized spherical silica fine powder needs to have a water content of 0.5 wt% or less.
• the amount of moisture affects the magnitude of the charge amount and the environmental difference (difference in charge amount between high temperature and high humidity and low temperature and low humidity).
• a preferable water content is 0.4 wt% or less, more preferably 0.3 wt% or less.
• the amount of water may be, for example, 0.5, 0.4, 0.3, 0.2, 0.1, 0.05, or 0.01 wt% or less, or may be in the range of any two values thereof.
• the water content of the hydrophobized spherical silica fine powder can be measured using the Karl Fischer method.
• Karl Fischer measurement a moisture vaporizer VA-122 manufactured by Mitsubishi Chemical Corporation and a moisture analyzer CA-100 manufactured by Mitsubishi Chemical Corporation are used.
• Aquamicron AX manufactured by Mitsubishi Chemical Corporation
• catholyte is used as the anolyte of the moisture analyzer.
• Aquamicron CXU Mitsubishi Chemical Corporation was used.
• the background value was fixed at 0.20 ( ⁇ g / sec), and the measurement was continued until the detected water content fell below the background value.
• the hydrophobized spherical silica fine powder is not exposed to the outside air, and the moisture generated from the moisture vaporizer is introduced into the Karl Fischer device along with 300 ml / min of high-purity argon. The amount was measured.
• the hydrophobized spherical silica fine powder is allowed to stand for 24 hours at a temperature of 25 ° C. and a relative humidity of 55%, and then charged into the device until the heating temperature of the electric heater of the moisture vaporizer reaches 200 ° C.
• the amount of water generated was defined as the amount of water.
• the hydrophobized spherical silica fine powder needs to have a tap density of 0.10 g / cm 3 or more and 0.40 g / cm 3 or less.
• the tap density is less than 0.10 g / cm 3
• the tap density exceeds 0.40 g / cm 3
• Preferred tap density is at 0.13 g / cm 3 or more 0.35 g / cm 3 or less, more preferably 0.15 g / cm 3 or more 0.30 g / cm 3 or less.
• the tap density may be, for example, 0.10, 0.11, 0.15, 0.19, 0.20, 0.21, 0.25, 0.29, 0.30, 0.31, 0.35, 0.39, or 0.40 g / cm 3 , and any two values thereof It may be within the range.
• the tap density of the hydrophobized spherical silica fine powder can be measured using a powder tester.
• a powder tester As a measuring device, “PT-E type” manufactured by Hosokawa Micron Corporation was used. Hydrophobized spherical silica fine powder that was allowed to stand for 24 hours under conditions of a temperature of 25 ° C. and a relative humidity of 55% was placed in a 100 ml cup, and the apparent density was measured after tapping 180 times at a rate of once per second.
• the hydrophobized spherical silica fine powder preferably has an average particle size of 0.080 ⁇ m or more and 0.200 ⁇ m or less as measured by a laser diffraction / scattering particle size distribution analyzer, and has a maximum particle size of It is preferable that it is 0.800 micrometer or less.
• the average particle size is less than 0.080 ⁇ m, when used as an external toner additive, the spacer effect may be gradually lowered due to burying in the toner with time.
• the average particle diameter exceeds 0.200 ⁇ m and / or the maximum particle diameter exceeds 0.800 ⁇ m, the fluidity of the toner external additive may be lowered due to the influence of the large diameter particles.
• the average particle size is more preferably 0.085 ⁇ m or more and 0.180 ⁇ m or less, and most preferably 0.090 ⁇ m or more and 0.160 ⁇ m or less.
• the maximum particle diameter is more preferably 0.700 ⁇ m or less, and most preferably 0.600 ⁇ m or less.
• the particle size distribution of the hydrophobized spherical silica fine powder can be measured using “LS-230” manufactured by Beckman Coulter.
• ethanol was used as a solvent, and dispersion treatment was performed with an output of 200 W using “Ultrasonic Generator UD-200 (with ultra-trace chip TP-040)” manufactured by Tommy Seiko Co., Ltd. for 3 minutes as a pretreatment.
• concentration of PIDS Polygonalization Intensity Differential Scattering
• the refractive index of ethanol was 1.36
• the refractive index of hydrophobized spherical silica fine powder was 1.50.
• particles having a cumulative mass of 50% are the average particle size
• a particle size having a cumulative mass of 100% is the maximum particle size.
• the hydrophobized spherical silica fine powder has particles having a projected area equivalent circle diameter of 0.100 ⁇ m or more measured by microscopy having an average sphericity of 0.88 or more, and a projected area equivalent circle diameter measured by microscopy of 0.
• the number ratio of particles having a sphericity of 0.85 or less is 20% or less
• the total number of particles having a projected area equivalent circle diameter of 0.100 ⁇ m or more by microscopy is 100%.
• the number ratio of the particles of 0.80 or less is preferably 10% or less.
• Particles with low sphericity often have a structure structure or form aggregates, and the tendency becomes more pronounced as the sphericity decreases.
• particles having a projected area equivalent circle diameter of 0.100 ⁇ m or more measured by a microscopic method have an average sphericity of 0.88 or more and the total number of particles projected by a microscope projected area equivalent diameter of 0.100 ⁇ m or more is 100%, If the number ratio of particles having a sphericity of 0.85 or less is 20% or less and the number ratio of particles having a sphericity of 0.80 or less is 10% or less, there are few structure structure particles and aggregates, and the toner is used as an external toner additive. Better charging stability can be achieved.
• the average sphericity of particles having a projected area equivalent circle diameter of 0.100 ⁇ m or more measured by microscopy is more preferably 0.90 or more, and most preferably 0.92 or more. Further, when the total number of particles having a projected area equivalent circle diameter of 0.100 ⁇ m or more measured by microscopy is 100%, the number ratio of particles having a sphericity of 0.85 or less is 15% or less and the sphericity is 0.80 or less. The number ratio is more preferably 8% or less, the number ratio of particles having a sphericity of 0.85 or less is most preferably 10%, and the number ratio of particles having a sphericity of 0.80 or less is most preferably 6% or less.
• the sphericity of the hydrophobized spherical silica fine powder can be measured by the following method. After fixing the hydrophobized spherical silica powder to the sample stage with carbon paste, osmium coating was performed, and an image taken with a scanning electron microscope “JSM-6301F type” manufactured by JEOL Ltd. with a magnification of 50000 times and a resolution of 2048 ⁇ 1356 pixels I imported it into my computer. This image was taken into an image analysis apparatus “MacView Ver. 4” manufactured by Mountec Co., Ltd., and the sphericity was measured from the projected area (A) and the perimeter (PM) of the particles.
• JSM-6301F type manufactured by JEOL Ltd.
• the sphericity of 200 particles having an arbitrary projected area equivalent circle diameter of 0.100 ⁇ m or more thus obtained was determined, and the average value was taken as the average sphericity. Further, the ratio of the number of each particle was calculated from the number of particles having a sphericity of 0.85 or less, or 0.80 or less in these 200 particles.
• the method for hydrophobizing spherical silica fine powder in one embodiment of the present invention will be described.
• the inventor Prior to hydrophobizing with hexamethyldisilazane, the inventor activated silanol groups by preliminarily adsorbing moisture on the surface of the spherical silica fine powder, and highly reacted hexamethyldisilazane on the surface of the spherical silica fine powder. It has been found that the charging stability of the hydrophobized spherical silica fine powder can be improved.
• the present inventors further adsorbed hexamethyldisilazane into spherical silica by adsorbing moisture in the state of water vapor and under specific temperature and humidity conditions, rather than simply spraying and adsorbing water when adsorbing moisture. It was found that the surface of the fine powder could be bonded very uniformly with a high reaction rate, and the charging stability of the hydrophobized spherical silica fine powder could be further improved. In addition, it has been found that the occurrence of aggregation due to the influence of moisture can be remarkably reduced, and is effective in improving fluidity.
• the hydrophobized spherical silica fine powder is produced by a method of hydrophobizing with hexamethyldisilazane at a temperature of 35 ° C. to 55 ° C. and an absolute humidity of 40 g / m 3 to 100 g / m 3. It is preferable to use fine spherical silica powder that has been allowed to stand for 24 hours or more under the following conditions. Before hydrophobizing with hexamethyldisilazane, the spherical silica fine powder is allowed to stand for 24 hours or more under conditions of a temperature of 35 ° C. or more and 55 ° C.
• the amount of water present on the surface of the spherical silica fine powder is reduced, so that the uniform hydrophobicity when the hydrophobic treatment is performed with hexamethyldisilazane Therefore, when used as an external toner additive, the charging stability due to changes over time cannot be sufficiently improved.
• the standing time is less than 24 hours, which is not preferable because the amount of water present on the surface of the spherical silica fine powder is reduced.
• the temperature is higher than 55 ° C.
• the spherical silica fine powder is agglomerated by the action of liquid crosslinking acting between the spherical silica fine powders. For this reason, when the hydrophobization treatment is performed with hexamethyldisilazane, the hydrophobicity inside the aggregate of the spherical silica fine powder is lowered, and as a result, the charging stability due to the change with time cannot be sufficiently improved.
• the temperature is more preferably 37 ° C. or more and 53 ° C. or less, and most preferably 40 ° C. or more and 50 ° C. or less. Further, more preferably absolute humidity 45 g / m 3 or more 90 g / m 3 or less, 50 g / m 3 or more 80 g / m 3 or less is most preferred.
• the spherical silica fine powder 1 m 2 per, 4.0 ⁇ 10 - It is preferable to spray 6 mol or more and 1.5 ⁇ 10 ⁇ 5 mol or less of hexamethyldisilazane.
• the spray amount of hexamethyldisilazane is less than 4.0 ⁇ 10 ⁇ 6 mol per 1 m 2 of the spherical silica fine powder, the uniform hydrophobicity becomes insufficient and changes over time when used as an external toner additive. The charging stability due to cannot be sufficiently improved.
• the spray amount of hexamethyldisilazane is more preferably 5.5 ⁇ 10 ⁇ 6 mol or more and 1.4 ⁇ 10 ⁇ 5 mol or less, and 7.0 ⁇ 10 ⁇ 6 mol or more per 1 m 2 of spherical silica fine powder. Most preferred is 3 ⁇ 10 ⁇ 5 mol or less.
• the hexamethyldisilazane spraying method is, for example, a method of spraying the stock solution in a state where the spherical silica fine powder raw material is suspended, or a method of spraying hexamethyldisilazane and then gasifying and contacting the spherical silica fine powder. There is.
• hexamethyldisilazane may be treated alone with respect to the spherical silica fine powder raw material, or treated with two or more kinds of surface treatment agents. You may do it.
• the aminosilane coupling agent is used in combination with an aminosilane coupling agent for imparting positive chargeability, first, the aminosilane treatment is performed on the spherical silica fine powder, and then the hydrophobization treatment method in one embodiment of the present invention may be performed.
• the hydrophobized spherical silica fine powder in one embodiment of the present invention preferably has a hydrophobization degree of 50% or more. If the degree of hydrophobicity is less than 50%, the charging characteristics of the toner in a high-humidity environment are deteriorated, or the toner particles are aggregated to decrease the fluidity. More preferably 55% or more, and most preferably 60% or more.
• the degree of hydrophobicity can be measured by the following method. That is, 50 ml of ion-exchanged water and 0.2 g of a sample are put in a beaker, and methanol is dropped from a burette while stirring with a magnetic stirrer.
• the powder gradually settles, and the volume% of methanol in the mixed solution of methanol and ion-exchanged water at the end point when the total amount of the powder is settled is defined as the degree of hydrophobicity (%).
• the spherical silica fine powder used in the method for producing a hydrophobized spherical silica fine powder in one embodiment of the present invention is obtained by oxidizing metal silicon in order to realize the hydrophobized spherical silica fine powder having the water content and sphericity of the present invention. It is preferable to use the spherical silica fine powder obtained in (1).
• a method for producing spherical silica fine powder a method in which metal silicon is spheroidized while being subjected to an oxidation reaction by being applied to a high temperature field formed by a chemical flame or an electric furnace (for example, Japanese Patent No. 1568168), metal silicon Examples thereof include a method in which a particle slurry is sprayed into a flame and spheroidized while undergoing an oxidation reaction (for example, JP-A-2000-247626).
• the spherical silica fine powder used in the method for producing a hydrophobized spherical silica fine powder in one embodiment of the present invention has a water content of 0.4 wt% or less, and an average particle measured by a laser diffraction scattering type particle size distribution analyzer. It is preferable to use a fine spherical silica powder having a diameter of 0.070 ⁇ m or more and 0.170 ⁇ m or less and a maximum particle diameter of 0.300 ⁇ m or less.
• the water content of the spherical silica fine powder is 0.4 wt% or less, the average particle size is 0.070 ⁇ m or more and 0.170 ⁇ m or less, and the maximum particle size is 0.300 ⁇ m or less, thereby making the hydrophobic spherical shape in one embodiment of the present invention. It becomes easy to realize a water content of silica fine powder of 0.5 wt% or less, an average particle size of 0.080 ⁇ m to 0.200 ⁇ m, and a maximum particle size of 0.800 ⁇ m or less.
• the amount of the hydrophobized spherical silica fine powder blended in the toner according to an embodiment of the present invention is usually preferably 0.1 to 6 parts by mass, more preferably 0.3 to 4 parts by mass with respect to 100 parts by mass of the toner. Part. If the blending amount is too small, the adhesion amount to the toner is small and a sufficient spacer effect cannot be obtained. If the blending amount is too large, the hydrophobic spherical silica fine powder may be detached from the toner surface.
• the silica powder of the toner external additive containing the hydrophobized spherical silica fine powder in one embodiment of the present invention is not limited to the use of the hydrophobized spherical silica fine powder in one embodiment of the present invention alone.
• it can be used in combination with ultrafine powder silica of about 200 to 500 m 2 / g, which has a high fluidity-imparting effect.
• the electrostatic image developing toner to which the toner external additive containing the spherical silica fine powder in one embodiment of the present invention is added a known toner composed mainly of a binder resin and a colorant can be used. . Moreover, the charge control agent may be added as needed.
• the toner for developing an electrostatic image to which an external toner additive containing a hydrophobic spherical silica fine powder according to an embodiment of the present invention is added can be used as a one-component developer, and can be mixed with a carrier to form a two-component developer. It can also be used as a component developer.
• the toner external additive may not be added to the toner particles in advance, but may be added when the toner and the carrier are mixed to coat the surface of the toner.
• the carrier iron powder or the like, or a known one whose surface is resin-coated is used.
• Examples 1 to 14 Comparative Examples 1 to 10 Spherical silica fine powder is manufactured using a device in which an LPG-oxygen mixed burner with a double pipe structure capable of forming an inner flame and an outer flame is installed at the top of the combustion furnace, and a collection system line is directly connected to the lower part. did. A two-fluid nozzle for slurry spraying is further installed at the center of the burner, and a slurry (metal silicon concentration: 10 to 70% by mass) composed of metal silicon powder (average particle size 10.5 ⁇ m) and water is formed from the center.
• Table 1 shows the water content, average particle size, and maximum particle size of the fine spherical silica powder.
• the obtained spherical silica fine powders were respectively placed in a constant temperature and humidity chamber (“EC-45MHP” manufactured by Hitachi Appliances) and left in the bath under various conditions.
• Tables 1, 2, and 3 show the temperature, absolute humidity, and time when left in the tank.
• each spherical silica fine powder taken out from the constant temperature and humidity chamber was immediately charged into a fluidized bed (Chuo Kakoki Co., Ltd. “vibrating fluidized bed apparatus VUA-15 type”) and fluidized with N 2 gas.
• Silazane (“SZ-31” manufactured by Shin-Etsu Chemical Co., Ltd.) was sprayed in various spray amounts and fluidly mixed for 20 minutes. After fluid mixing, the temperature was raised to 130 ° C., and ammonia formed while removing nitrogen gas was removed to obtain hydrophobized spherical silica fine powders A to W.
• hydrophobization treatment was performed in the same manner as above to obtain hydrophobized spherical silica fine powder X.
• the spray amounts of hexamethyldisilazane are shown in Table 1, Table 2, and Table 3.
• Compressibility (Fixed apparent specific gravity-Loose apparent specific gravity) / Fixed apparent specific gravity x 100 (%)
• the loose apparent specific gravity is a specific gravity measured with a pseudo-toner placed in a 100 ml cup and without tapping.
• the solid apparent specific gravity is a pseudo-toner put into a 100 ml cup at a rate of once per second.
• the apparent specific gravity measured after tapping 180 times.
• the compression time was measured by changing the mixing time of the Henschel mixer from 3 minutes to 30 minutes, and the compression ratio change ratio was calculated from the following equation.
• Compressibility change ratio compression degree when mixing time is 30 minutes / compression degree when mixing time is 3 minutes
• the compressibility change ratio is closer to 1, that is, the smaller the change in the compression degree, the better the spacer effect is Represents.
• a simulated toner that was allowed to stand for 24 hours under the conditions of a temperature of 25 ° C. and a relative humidity of 55% was placed on a sieve having a mesh opening of 710 ⁇ m and deposited on a circular measuring table having a diameter of 8 cm through a funnel while applying vibration.
• the angle of the line of the deposited powder with respect to the horizontal plane was defined as the angle of repose using a protractor. It shows that fluidity
• the suction time was 3 minutes, the suction pressure was 4.0 kPa, and a screen of 32 ⁇ m mesh was used for the screen used for separating the simulated toner and the carrier.
• Charge retention ratio Blow-off charge amount after 120 minutes of shaking / Blow-off charge amount after 5 minutes of shaking The value of this charge holding ratio is closer to 1, that is, the smaller the change in the charge amount, the more stable the charge is with time. Represents good.
• External additive coverage per pseudo toner (total projected area of spherical silica fine powder adhering to the surface of one crosslinked styrene resin powder / projected area of one crosslinked styrene resin powder) ⁇ 100 (%) The external additive coverage was calculated for 20 pseudo toners, and the average value was taken as the average external additive coverage.
• the hydrophobized spherical silica fine powder of the present invention is used as an external additive for electrophotographic toners used in copying machines, laser printers and the like.

Landscapes

• Chemical & Material Sciences (AREA)
• Inorganic Chemistry (AREA)
• Organic Chemistry (AREA)
• Physics & Mathematics (AREA)
• General Physics & Mathematics (AREA)
• Developing Agents For Electrophotography (AREA)
• Silicon Compounds (AREA)

Priority Applications (1)

Applications Claiming Priority (2)

Publications (1)

Family

ID=53004232

Family Applications (1)

Country Status (3)

Cited By (1)

Citations (4)

Family Cites Families (5)

• 2014
  • 2014-10-29 WO PCT/JP2014/078741 patent/WO2015064632A1/ja active Application Filing
  • 2014-10-29 JP JP2015545264A patent/JP6429791B2/ja active Active
  • 2014-10-30 TW TW103137532A patent/TWI626216B/zh active

Patent Citations (4)

Also Published As

Similar Documents

Legal Events