JP4864475B2 - Electrostatic latent image developing toner, image forming method, process cartridge, and image forming apparatus - Google Patents

Description

  The present invention relates to a toner for developing an electrostatic latent image, and more particularly to a toner for developing an electrostatic latent image used in a full-color image forming apparatus such as a full-color copying machine or a full-color laser beam printer.

  In recent years, there has been a growing need for eco-friendly, compact and inexpensive personal use copiers and laser printers. In response to such demands for environmental friendliness, miniaturization, and cost reduction, it has recently been studied to use contact charging means without using a corona discharger. Specifically, while applying a voltage to a conductive roller that is a charging member, the roller is brought into contact with a member to be charged such as a photosensitive member, and the surface of the member to be charged is charged to a predetermined potential. If such contact charging means is used, the unit can be simplified, miniaturized, and the voltage can be reduced as compared with the corona discharger, and the amount of ozone generated can be reduced.

  On the other hand, in the contact charging device, the charging member is applied with a DC voltage or a DC voltage superimposed with an AC voltage. At this time, in the vicinity of the contact portion between the charging member and the photosensitive drum, abnormal charging and flying motion of the residual toner particles having a small particle diameter and light weight are repeated. For this reason, there is a situation where electrostatic adsorption or embedding of residual toner on the charging member or the surface of the photosensitive drum is likely to be performed, and the contact charging unit is very different from the case of using a non-contact charging unit by a conventional corona discharger, The charging performance has a drawback that it easily changes with time.

Also, due to similar market needs, recently, a fixing mechanism for a color copying machine or a color laser printer using an oilless fixing device has been rapidly spread.
By making the fixing mechanism of the color output machine oil-free, the fixing unit can be simplified, and since oil is not consumed as a consumable item, it is effective in reducing running costs.

The toner used in such an oilless color image fixing device must have glossiness in order to improve the release function and obtain a preferable color image. It is difficult to achieve both, and it is a conflicting characteristic item.
In recent years, various attempts have been made to formulate and design toners against these conflicting properties. In pulverized toners, the material properties of resins and waxes (release agents) and the dispersion technology of wax domains have been used to improve the conflicting properties. There are many attempts to achieve both. In addition, it is possible to relatively increase the wax content in the polymerization method toner and the wet granulation method toner in comparison with the pulverization method toner from the manufacturing principle. Since it can be controlled, in recent years, the development of a construction method and a formulation have been very actively carried out as a toner method suitable for oilless fixing.

  However, in general, a toner that is highly filled with a wax, whether it is a pulverized toner or a polymerized toner, is free of wax on the surface, and is liable to cause image noise in processes other than fixing. In particular, when free wax is filmed on the developer carrier or latent image carrier in the developing section, it causes adverse effects such as charging failure, and causes image noise such as fogging, and further fills the latent image carrier. The wax that has been mingled is transferred to the contact charging member, the charging ability of the member is lowered, and there is also a secondary adverse effect that the charging failure of the latent image carrier is caused.

Furthermore, in the case of a polymerization method toner, since it is generally produced by granulation in an aqueous system, the charging performance of the toner base particles is inferior to that of the pulverization method toner due to the influence of a surfactant added at the time of manufacture, Furthermore, image noise such as fog is likely to deteriorate.

Further, as described above, when the toner is highly filled with wax, it is difficult to disperse the wax when it is manufactured by a pulverization method, so that the distribution of the wax dispersion particle size is likely to be wide and free wax is likely to be generated. As a result, the toner composition tends to be non-uniform, resulting in a broad toner charge distribution, and noise problems such as fogging due to poorly charged toner become significant.
Furthermore, as a problem caused by the dispersion of the wax, the agglomeration property of the toner powder is deteriorated. As a result, the transfer property is deteriorated, and problems such as missing characters and fine lines occur.

  As a means of suppressing filming on the member of such an oilless fixing color toner, in addition to the prescription design of toner base particles that suppress the release of wax and other toner additives that are the cause of filming, Measures such as external addition of an abrasive material to the surface of toner particles to remove the filming material and external addition of a lubricating material to make the filming material difficult to adhere to the member are being studied.

  As a polishing agent for removing a filming substance, a method of adding hard inorganic fine particles of several hundred nanometers has been disclosed conventionally. For example, Patent Document 1 is effective by adding cerium oxide as a polishing agent. Describes that the filming substance can be removed. Further, Patent Document 2 describes that the filming substance can be effectively removed by adding strontium titanate particles having a particle size range of 200 to 800 nm.

  However, although these means have a high effect of removing the filming substance on the photosensitive member having the cleaning blade, in general, a member such as a contact charging roller having no friction member such as a regulating blade or a cleaning blade is added rather. There exists a subject that an abrasive | polishing agent will transfer to a contact charging member and the charging performance will deteriorate remarkably. That is, the known abrasive substance has a problem that it is poorly contaminated with respect to the charging member in the contact charging method.

On the other hand, as a lubricant that makes it difficult to adhere filming substances, a method of adding metal soap is widely known. However, this method does not prevent filming on the photoreceptor due to the lubricating effect. However, there is a problem that the chargeability is greatly changed, such as charging of the toner, and the charging stability is deteriorated.
On the other hand, magnesium silicate minerals (attapulgite, sepiolite, etc.) described in Patent Document 3 are effective for filming during cleaning, but have a high water content and are liable to cause poor charging even in normal use environments. Problems due to poor charging such as dirt, toner leakage, and toner scattering are likely to occur.

  Similarly, when the magnesium silicate treated with the silicone oil described in Patent Documents 4, 5, and 6 is used, the toner fluidity is deteriorated due to the silicone oil, the charge is increased, etc., causing the conveyance failure and the density decrease in the developing device. . Further, since the magnesium silicate having a particle size as described in the examples has a particle size of 2 μm or more, it is easy to be detached in the developing device, and the developing member, the latent image carrier, etc. are scratched, and the image Will be adversely affected.

In the toner described in Patent Document 7, there is a description that a silicate fine powder is made of magnesium silicate, and a toner having a coverage of 60 to 100% is prepared. Cheap. This is because magnesium silicate tends to be positively charged due to the influence of the MgO portion, which tends to be strongly positively charged, as shown by the relationship of electronegativity (Non-patent Document 1).
When titanic acid fine powder is used as in the toner described in Patent Document 8, an excellent effect on filming is exhibited, but since the material itself has low resistance, charging leakage is large. Soil stains, toner leakage, and toner scattering are likely to occur. In addition, there is a problem that the charge imparting performance of the charging member when it is shifted to the charging member is greatly deteriorated.

Even when titania is used as in the toner described in Patent Document 9, it is difficult to adjust the amount of addition because this material is a low-resistance and high-dielectric constant material. In addition, when the amount is small, the charge is increased. As a result, in both cases, scumming, toner leakage, and toner scattering are likely to occur.
As described above, in the full-color toner with high wax filling, the actual situation is that filming, chargeability, and member contamination are contradictory characteristics.
Japanese Patent No. 2656230 Japanese Patent No. 3407545 JP 2002-31913 A JP-A-3-294864 JP-A-4-214568 JP-A-5-165257 JP 11-95480 A JP-A-11-184239 JP 2003-186240 A Journal of the Imaging Society of Japan Vol.39 No.3 259

An object of the present invention is to provide a toner for developing an electrostatic latent image that solves the above-described problems.
That is, the present invention provides a toner for developing an electrostatic latent image that suppresses filming, sticking, and scratches on a photoreceptor and has excellent blade cleaning properties.
Provided is a toner capable of suppressing deterioration of charging performance due to migration (contamination) of a toner component with respect to a charging member in a contact charging system, and obtaining stable charging performance.
Provided is a toner having a good transferability, which contains a large amount of a release agent, improves the agglomeration property of a full color toner for oilless fixing having a poor powder agglomeration property, and does not cause problems such as transfer loss.
Charging that contains a large amount of release agent, improves the charging property of oilless fixing full-color toner with poor charging property (broad charging distribution), and does not cause problems such as fogging in various environments and durability Toner having good properties is provided.
Furthermore, a toner with good chargeability is provided in the wet granulation method toner in which chargeability tends to deteriorate.
An image forming method, a process cartridge, and an image forming apparatus that solve the above problems are provided.

It has been found that the above-mentioned problems can be solved by the following configuration of the present invention (claims 1 to 15).
(1) Toner mother particles containing at least a colorant, a release agent and a binder resin, hydrophobic silica fine particles A having a number average particle diameter of 5 to 20 nm, and hydrophobic particles having a number average particle diameter of 20 to 100 nm Fine particles B selected from crystalline titania and / or silica, an average primary particle size of 0.01 to 0.5 μm, and an average secondary particle size formed by aggregation of the primary particles of 0.02 to 2.0 μm In the range of silica (SiO ₂ ) and magnesia (MgO), the molar ratio of magnesia (MgO) / silica (SiO ₂ ) is in the range of 0.8 to 2.2, and by X-ray diffraction, forsterite, selected from enstatite, composite oxide particles C identified in any of steatite are externally added, the forsterite in the toner, the group consisting of enstatite and steatite Without even electrostatic latent image developing toner characterized by containing one.

(2) The electrostatic latent image developing toner according to (1) above, wherein the composite oxide particles C have a number average particle size in the range of 0.02 to 2.0 μm.

( 3 ) The electrostatic latent image developing toner according to (1) or (2) , wherein the fine particles A and the fine particles B are hydrophobic and have a hydrophobicity of 50 to 90.
( 4 ) The total addition amount of the fine particles A and the fine particles B is 2 to 5% by weight with respect to the toner base particles, and the addition amount of the composite oxide particles C is 0.2% with respect to the toner base particles. The toner for developing an electrostatic latent image according to any one of (1) to ( 3 ), wherein the toner is 3 to 5% by weight.

( 5 ) The toner for developing an electrostatic latent image according to any one of (1) to ( 4 ), wherein a weight ratio of the fine particles A to the fine particles B is 1: 9 to 7: 3.

( 6 ) The electrostatic oxide image development according to any one of (1) to (5), wherein the composite oxide particles C have an average primary particle size of 0.02 to 0.15 μm. toner.
( 7 ) The electrostatic latent image development according to any one of (1) to (6), wherein the composite oxide particles C have an average secondary particle size of 0.1 to 2.0 μm. Toner.

( 8 ) The composite oxide particles C are obtained by sintering Mg (OH) ₂ powder or MgO powder and SiO ₂ powder having an average primary particle size of 10 μm or less. The electrostatic latent image developing toner according to any one of 1) to ( 7 ).
( 9 ) The electrostatic latent image according to any one of (1) to ( 8 ), wherein the toner base particles have a volume average diameter of 4 to 9 μm and are used in a non-magnetic one-component development system. Toner for image development.
( 10 ) The electrostatic latent image development according to any one of (1) to ( 8 ), wherein the toner base particles have a volume average diameter of 4 to 9 μm and are used in a two-component development system. Toner.

( 11 ) The toner base particle according to (1), wherein the toner base particle contains at least 3.5 to 10% by weight of a release agent, and is a full-color image forming toner for oilless fixing produced by a pulverization method. The toner for developing an electrostatic latent image according to any one of to ( 8 ).
( 12 ) The toner base particle is a full-color image forming toner for oilless fixing, which contains at least 5 to 12% by weight of a release agent and is granulated in a wet process. The toner for developing an electrostatic latent image according to any one of 1) to ( 8 ).

( 13 ) At least a rotatable image carrier, a charging step arranged in contact with the image carrier, and charging the image carrier to a predetermined potential, a rotating toner conveying member, and the toner. An image forming method comprising: a toner supplying member to be supplied to the toner, wherein the toner is the electrostatic latent image developing toner according to any one of (1) to ( 12 ). An image forming method.

( 14 ) Used in an image forming apparatus for forming an image by transferring a toner to an electrostatic latent image formed on a photoreceptor and visualizing it to form a toner image and transferring the toner image to a transfer material. A process cartridge configured to be detachable from the apparatus, a photosensitive member, a charging unit that contacts the photosensitive member and charges the photosensitive member, and a latent image that forms an electrostatic latent image on the photosensitive member. At least one selected from image forming means, transfer means for transferring the toner image to a recording material, and cleaning means for removing toner remaining on the photoreceptor after the toner image is transferred to the transfer material. Means and a developing means for developing the electrostatic latent image formed on the photosensitive member with toner to form a toner image, and the toner is supported by (1) to ( 12 ). Any A process cartridge, which is a toner for developing an electrostatic latent image.
( 15 ) In an image forming apparatus for forming an image by transferring toner to an electrostatic latent image formed on a photoreceptor and visualizing it to form a toner image and transferring the toner image to a transfer material, An image forming apparatus, wherein the toner is the electrostatic latent image developing toner according to any one of (1) to ( 12 ).

The toner of the present invention is obtained by externally adding specific inorganic particles A, B and C to toner particles.
“External addition” refers to addition to the toner base particles obtained in advance so as to be present on the surface (external) of the toner base particles.
The present invention uses fine particles A and fine particles B externally mixed with toner base particles (toner particles) having a specific number average particle diameter and a specific hydrophobicity at a specific addition amount, By using together the inorganic fine particles (composite oxide particles C) having a specific number average particle size, the above-mentioned problems are solved.
In the present invention, as the fine particles A, hydrophobic silica fine particles having a primary particle number average particle size of 5 to 20 nm, preferably 7 to 15 nm, and a hydrophobicity of 50 or more, preferably 55 to 90 are used. By using such silica fine particles, it is possible to improve the fluidity of the toner to improve the gradation reproducibility and to impart lubricity to the photosensitive member of the cleaning blade. When the average particle diameter is larger than 20 nm, the effect of improving the fluidity of the toner and the effect of improving the lubricity of the cleaning blade are insufficient. On the other hand, when the average particle size is smaller than 5 nm, embedding in toner particles is likely to occur, and the change in powder characteristics during printing durability increases, and environmental stability decreases. If the degree of hydrophobicity is lower than 50, fogging occurs on the white background of the image in a high temperature and high humidity environment.

The fine particles B are fine particles selected from hydrophobic silica and / or titania having a number average particle size of primary particles of 20 to 100 nm, preferably 25 to 80 nm and a hydrophobization degree of 50 or more, preferably 55 to 90. use. By using such fine particles, it is possible to prevent white spots in the transfer step in the full-color image forming method, particularly secondary transfer in the case of using an intermediate transfer belt, and to improve heat resistant storage stability. When the average particle size is larger than 100 nm, the coverage with respect to the toner is decreased, so that the environmental stability, the heat resistant storage property and the white spot prevention effect are deteriorated. As a result, the fine particles B are easily embedded in the toner particles. As a result, the effect of suppressing the aggregation of the developer is reduced, and white spots are easily generated in the solid image. As fine particles B of the present invention, silica or titania may be used as long as they satisfy the above-mentioned specified range. In particular, in order to suppress a decrease in image density due to charge-up in a low temperature and low humidity environment in a two-component development system. It is effective to use titania. Further, silica and titania within the above specified ranges may be used in combination as appropriate in order to adjust the charging level and charging environment fluctuation.
As titania fine particles, anatase titania, rutile titania, amorphous titania, and the like can be used.

  The total amount of fine particles B selected from silica fine particles A and silica and / or titania is 2 to 5% by weight, preferably 2 to 3.5% by weight, based on the toner base particles. If the addition amount is less than 2% by weight, the white spot prevention effect is insufficient, and if it exceeds 5% by weight, filming (contamination) on the charging member or the latent image carrier due to the free external additive tends to occur. The added weight ratio between the fine particles A and the fine particles B varies depending on the respective particle diameters and the like, but cannot be generally stated. However, it is used in a ratio of 1: 9 to 7: 3, preferably 2: 8 to 6: 4. desirable. When the amount of fine particles A is larger than this range, it is difficult to obtain the effect of improving transfer omission, and when the amount of fine particles B is larger than this range, the toner fluidity is significantly reduced, and in the one-component development method, the toner is transferred onto the developing roller. Thin layer formation defects are likely to occur, which is not preferable.

  Silica fine particles A and fine particles B are surface-treated with a hydrophobizing agent. As such a hydrophobizing agent, a silane coupling agent, a titanate coupling agent, silicon oil, silicon varnish, or the like can be used. Examples of silane coupling agents include hexamethyldisilazane, trimethylsilane, trimethylchlorosilane, dimethyldichlorosilane, methyltrichlorosilane, allyldimethylchlorosilane, benzyldimethylchlorosilane, methyltrimethoxysilane, methyltriethoxysilane, and isobutyl. Trimethoxysilane, dimethyldimethoxysilane, dimethyldiethoxysilane, trimethylmethoxysilane, hydroxypropyltrimethoxysilane, phenyltrimethoxysilane, n-butyltrimethoxysilane, n-hexadecyltrimethoxysilane, n-octadecyltrimethoxysilane, Vinyltrimethoxysilane, vinyltriethoxysilane, γ-methacryloxypropyltrimethoxysilane, vinyltriacetoxysilane, etc. A possible use, silicone - as is N'oiru, such as dimethylpolysiloxane, methylhydrogenpolysiloxane, methylphenyl polysiloxane can be used.

In order to surface-treat the base material of silica or titania with the hydrophobizing agent, for example, the hydrophobizing agent is diluted with a solvent, the diluting solution is added to the base material, mixed, the mixture is heated and dried, and then crushed. Or a wet method in which a base material is dispersed in an aqueous system to form a slurry, a hydrophobizing agent is added and mixed, and this is heated and dried, followed by crushing. In particular, for titania, it is preferable to perform a hydrophobization treatment in an aqueous system from the viewpoint of the uniformity of the surface treatment of the hydrophobizing agent and the ability to prevent aggregation of titania particles.
The degree of hydrophobicity in the present invention is measured by the methanol wettability method. First, methanol is dropped into water in which the sample is dispersed, and the methanol weight required to wet all the sample is measured. The percentage of methanol weight in water and methanol at this time was expressed as a percentage of hydrophobicity.

In the toner of the present invention, in addition to the fine particles A and B, the number average particle size composed of silica (SiO ₂ ) and magnesia (MgO) is 0.02 to 2.0 μm, preferably 0.02 or more. Composite oxide particles C in the range of less than 0 μm are added and mixed. The number average particle size in C refers to the primary particle size when the primary particles are monodispersed, or the particle size of the aggregated particles (secondary particles and the like) when the particles are aggregated.
The component composition of the composite oxide particles C is a material generally called magnesium silicate, and this material is a known material as described in the prior art. However, the composite oxide of the present invention has the following characteristics and is clearly different from the conventionally known magnesium silicate.
First, in the composite oxide of magnesia (MgO) and silica (SiO ₂ ) of the present invention, the molar ratio of MgO / SiO ₂ is desirably in the range of 0.8 to 2.2, more preferably 1.0. It is desirable to be in the range of ~ 2.0.

As a material in such a composite molar ratio range, the molar ratio is 0.8 to 1.2, and further is preferably 0.2.
In the case of 9 to 1.1, materials called steatite and enstatite correspond, and in the case of a molar ratio of 1.8 to 2.2, and further 1.9 to 2.1, a material called forsterite corresponds. Both can be identified by analysis by X-ray diffraction. As the composite oxide particle C, for example, a mixture of steatite, forsterite, etc. can be used as long as it satisfies the above specified range.
In general, MgO · SiO ₂ composite oxides called forsterite, steatite, and enstatite have properties similar to alumina, such as high thermal expansion, and are characterized by excellent dielectric properties at high frequencies and insulation resistance at high temperatures. It is a material and has been used as a ceramic for electronic parts for a long time.

However, since the conventional MgO.SiO ₂ composite oxide powder has a small average primary particle size of more than 0.2 μm and an average secondary particle size of 2 to 3 μm or more, it was added to the electrophotographic toner. In this case, there are problems such as poor dispersibility on the toner surface, adversely affecting the chargeability of the toner, and scratching the photoconductor due to the large particle size, and there has been a problem in application to toner.
The composite oxide particle C of the present invention is a particle that can solve the problem when such a conventional MgO.SiO ₂ composite oxide powder (magnesium silicate particle) is applied to a toner.
That is, the composite oxide particle C of the present invention has a particle size distribution that is clearly smaller than the conventional MgO · SiO ₂ composite oxide powder, and has an average primary particle size of 0.01 to 0.5 μm, Preferably, fine particles in a range of 0.02 to 0.15 μm form grape tuft-like sintered aggregates (secondary particles), and an average secondary particle size of 0.02 to 2.0 μm, More preferably, it is 0.1-2.0 micrometers.

By using the MgO.SiO ₂ composite oxide adjusted to such a particle size range, the problems of dispersibility on the toner surface and scratches on the members, which are the problems of the conventional magnesium silicate, are solved. It became possible.
The composite oxide particles C having such a particle size distribution are obtained by mixing and sintering Mg (OH) ₂ powder or MgO powder and SiO ₂ powder having an average primary particle size of 10 μm or less, As described above, those identified as forsterite, enstatite, and steatite by analysis by X-ray diffraction are suitable, and the materials thus produced are unreacted MgO, Mg (OH) ₂ , and SiO ₂ . Those containing no single substance are preferred. (For details, see JP-A-2
003-327470; see Titanium Industrial Material Basic Patent)

By using such composite oxide particles C in combination, the following excellent characteristics are obtained.
First, it is possible to eliminate filming (contamination) of a full color toner containing a large amount of wax and external additives on the charging member and the photosensitive member. This is because such composite oxide particles C contain the above-mentioned secondary particles, so that the composite oxide particles C released from the toner at the time of blade cleaning form a damming layer at the blade nip portion, and the blade nip portion. This is presumably because it has a function of reducing the amount of free wax, fine particles A, and fine particles B that pass through. If the number average particle size of the composite oxide particles C is smaller than 0.02 μm, the effect of preventing filming is insufficient. If the number average particle size is larger than 2.0 μm, the image is repeatedly formed, during blade cleaning, or full color image formation. In an apparatus or the like, the photosensitive member is easily damaged when pressed by a transfer drum or an intermediate transfer belt.

Secondly, there is almost no transfer to a charging member such as a charging roller in the contact charging method, and even if it is transferred, the electric resistance of the charging roller is excessive due to the electrical characteristics (high resistance and low dielectric constant) of the composite oxide particles C. It has an excellent characteristic that it does not change and, as a result, it is difficult to deteriorate the performance of the charging roller.
Thirdly, since the composite oxide particle C of the present invention contains magnesium, the charging polarity is likely to have a positive property, and since it has the above-described relatively large secondary particles, when used in a one-component development, at the time of development. The secondary effect of supplementing the negative chargeability of the toner particles when peeled from the toner has the secondary effect of supplementing the positive chargeability of the carrier by transferring the main particles to the carrier in the two-component development. As described above, it contains a large amount of a release agent and improves the chargeability of a full color toner for oilless fixing with poor chargeability (broad charge distribution). Furthermore, it can be used more effectively for toners with poor chargeability obtained by granulation in an aqueous wet system such as polymerized toners.

The composite oxide particles C of the present invention are added in an amount of 0.3 to 5.0% by weight, preferably 0.5 to 3.0% by weight, based on the toner particles. If the addition amount is less than 0.3% by weight, the effect of preventing filming is insufficient, and if it is more than 5% by weight, the influence on the chargeability of the toner increases, which is not preferable.
The composite oxide particles C may be surface-treated with the above hydrophobizing agent, amino coupling agent, amino silicone oil or the like, or may not be treated.
The specific surface area of the base material (base before surface treatment) of the composite oxide particle C having the above particle size range is 5 to 50 m ² / g, preferably 5 to 40 m ² / g.

The toner base particles to which the above inorganic particles are externally added are composed of at least a binder resin, a release agent and a colorant.
As the binder resin constituting the toner base particles, resins known in the fields of electrophotography and electrostatic printing can be used. For example, styrene resins; acrylic resins such as alkyl acrylates and alkyl methacrylates; styrene acrylic copolymers A resin, a polyester resin, a silicon resin, an olefin resin, an amide resin, an epoxy resin, or the like is preferably used.
In particular, when used in a full-color toner for oilless fixing, a polymer elastic resin component (first binder resin) and a sharp melt low molecular resin component (second binder) from the viewpoint of fixing separation and preferable image gloss. Resin) is preferably used in combination.

  The types of the first binder resin and the second binder resin are not particularly limited, and are known binder resins in the field of full-color toners, for example, polyester resins, (meth) acrylic resins, styrene- (meth) acrylic resins. The resin may be a copolymer resin, an epoxy resin, COC [cyclic olefin resin (for example, TOPAS-COC (manufactured by Ticona))] or the like. From the viewpoint of oilless fixing, the first binder resin and the second binder resin may be used. It is preferable to use a polyester resin for any of the resin.

As the polyester resin preferably used in the present invention, a polyester resin obtained by polycondensation of a polyhydric alcohol component and a polyvalent carboxylic acid component can be used. Among the polyhydric alcohol components, examples of the dihydric alcohol component include polyoxypropylene (2,2) -2,2-bis (4-hydroxyphenyl) propane, polyoxypropylene (3,3) -2,2- Bis (4-hydroxyphenyl) propane, polyoxypropylene (6) -2,2-bis (4-hydroxyphenyl) propane, polyoxyethylene (2,0) -2,2-bis (4-hydroxyphenyl) propane Bisphenol A alkylene oxide adducts such as ethylene glycol, diethylene glycol, triethylene glycol, 1,2-propylene glycol, 1,3-propylene glycol, 1,4-butanediol, neopentyl glycol, 1,4-butenediol, 1,5-pentanediol, 1,6-hexanedio , 1,4-cyclohexanedimethanol, dipropylene glycol, polyethylene glycol, polytetramethylene glycol, bisphenol A, hydrogenated bisphenol A, and the like. Examples of the trivalent or higher alcohol component include sorbitol, 1,2,3,6-hexanetetrol, 1,4-sorbitan, pentaerythritol, dipentaerythritol, tripentaerythritol, 1,2,
4-butanetriol, 1,2,5-pentanetriol, glycerol, 2-methylpropanetriol, 2-methyl-1,2,4-butanetriol, trimethylolethane, trimethylolpropane, 1,3,5-tri Examples thereof include hydroxymethylbenzene.
Among the polyvalent carboxylic acid components, examples of the divalent carboxylic acid component include maleic acid, fumaric acid, citraconic acid, itaconic acid, glutaconic acid, phthalic acid, isophthalic acid, terephthalic acid, cyclohexanedicarboxylic acid, and succinic acid. , Adipic acid, sebacic acid, azelaic acid, malonic acid, n-dodecenyl succinic acid, isododecenyl succinic acid, n-dodecyl succinic acid, isododecyl succinic acid, n-octenyl succinic acid, isooctenyl succinic acid, n-octyl succinic acid , Isooctyl succinic acid, anhydrides or lower alkyl esters of these acids.

  Examples of the trivalent or higher carboxylic acid component include 1,2,4-benzenetricarboxylic acid (trimellitic acid), 1,2,5-benzenetricarboxylic acid, 2,5,7-naphthalenetricarboxylic acid, 1,2 , 4-Naphthalenetricarboxylic acid, 1,2,4-butanetricarboxylic acid, 1,2,5-hexanetricarboxylic acid, 1,3-dicarboxyl-2-methyl-2-methylenecarboxypropane, 1,2,4- Examples include cyclohexanetricarboxylic acid, tetra (methylenecarboxyl) methane, 1,2,7,8-octanetetracarboxylic acid, pyromellitic acid, empole trimer acid, anhydrides of these acids, and lower alkyl esters.

  In the present invention, as a polyester resin, a polyester resin raw material monomer, a vinyl resin raw material monomer, and a mixture of monomers that react with both resin raw material monomers are used to obtain a polyester resin in the same container. A resin obtained by performing a condensation polymerization reaction and a radical polymerization reaction for obtaining a vinyl resin in parallel (hereinafter, simply referred to as “vinyl polyester resin”) can also be suitably used. In addition, the monomer which reacts with the raw material monomers of both resins is, in other words, a monomer that can be used for both the condensation polymerization reaction and the radical polymerization reaction. That is, it is a monomer having a carboxy group that can undergo a condensation polymerization reaction and a vinyl group that can undergo a radical polymerization reaction, and examples thereof include fumaric acid, maleic acid, acrylic acid, and methacrylic acid.

Examples of the raw material monomer for the polyester resin include the aforementioned polyhydric alcohol component and polyvalent carboxylic acid component. Examples of the raw material monomer for the vinyl resin include styrene, o-methylstyrene, m-methylstyrene, p-methylstyrene, α-methylstyrene, p-ethylstyrene, 2,4-dimethylstyrene, p-tert- Styrene or styrene derivatives such as butylstyrene and p-chlorostyrene; Ethylene unsaturated monoolefins such as ethylene, propylene, butylene and isobutylene; methyl methacrylate, n-propyl methacrylate, isopropyl methacrylate, n-butyl methacrylate , Isobutyl methacrylate, t-butyl methacrylate, n-pentyl methacrylate, isopentyl methacrylate, neopentyl methacrylate, 3- (methyl) butyl methacrylate, hexyl methacrylate, octyl methacrylate, nonyl methacrylate Methacrylic acid alkyl esters such as decyl methacrylate, undecyl methacrylate, dodecyl methacrylate; methyl acrylate, n-propyl acrylate, isopropyl acrylate, n-butyl acrylate, isobutyl acrylate, t-butyl acrylate, acrylic Alkyl acrylates such as n-pentyl acid, isopentyl acrylate, neopentyl acrylate, 3- (methyl) butyl acrylate, hexyl acrylate, octyl acrylate, nonyl acrylate, decyl acrylate, undecyl acrylate, and dodecyl acrylate Esters; unsaturated carboxylic acids such as acrylic acid, methacrylic acid, itaconic acid, maleic acid; acrylonitrile, maleic acid ester, itaconic acid ester, vinyl chloride, vinyl acetate, vinyl benzoate, vinylmethyl Examples include ethyl ketone, vinyl hexyl ketone, vinyl methyl ether, vinyl ethyl ether, and vinyl isobutyl ether. As a polymerization initiator when polymerizing the raw material monomer of the vinyl resin, for example, 2,2′-azobis (2,4-dimethylvaleronitrile), 2,2′-azobisisobutyronitrile, 1,1 Azo or diazo polymerization initiators such as' -azobis (cyclohexane-1-carbonitrile), 2,2'-azobis-4-methoxy-2,4-dimethylvaleronitrile, benzoyl peroxide, dicumyl peroxide, And peroxide polymerization initiators such as methyl ethyl ketone peroxide, isopropyl peroxycarbonate, lauroyl peroxide, and the like.

As the first binder resin and the second binder resin, various polyester resins as described above are preferably used. Among them, from the viewpoint of further improving the separation property and the offset resistance as an oilless fixing toner, It is more preferable to use the following first and second binder resins.
A more preferred first binder resin is a polyester resin obtained by polycondensation of the above-mentioned polyhydric alcohol component and polyhydric carboxylic acid component, particularly a bisphenol A alkylene oxide adduct as the polyhydric alcohol component. It is a polyester resin obtained using terephthalic acid and fumaric acid as the acid component.
More preferred second binder resins are vinyl polyester resins, particularly bisphenol A alkylene oxide adduct, terephthalic acid, trimellitic acid and succinic acid are used as raw material monomers for polyester resins, and styrene and butyl acrylate are used as raw material monomers for vinyl resins. And a vinyl-based polyester resin obtained using fumaric acid as a bireactive monomer.

  In the present invention, in order to increase the amount of wax necessary for oilless color fixing, it is preferable to add wax in advance to the binder resin. In this case, although it may be internally added to either the first binder resin or the second binder resin, the pulverized toner may be internally added to the first binder resin from the viewpoint of easily taking a share during kneading. preferable. In order to add the wax to the first binder resin in advance, when the first binder resin is synthesized, the wax is added to the monomer for synthesizing the first binder resin. Can be synthesized. For example, the polycondensation reaction may be performed in a state where a hydrocarbon wax is added to an acid monomer and an alcohol monomer constituting the polyester resin as the first binder resin. When the first binder resin is a vinyl polyester resin, the vinyl resin raw material monomer is dropped into the polyester resin raw material monomer while stirring and heating the hydrocarbon wax. Then, a polycondensation reaction and a radical polymerization reaction may be performed.

The weight ratio of the first binder resin (including the weight of the internally added wax) and the second binder resin in the toner particles is 20/80 to 45/55, preferably 30/70 to 40/60. If the amount of the first binder resin is too small, the separability and the high temperature offset resistance are deteriorated. When there is too much 1st binder resin, glossiness and heat-resistant storage property will fall.
More preferably, the softening point of the binder resin composed of the first binder resin and the second binder resin used in the above weight ratio is 100 to 125 ° C., particularly 105 to 125 ° C.

Examples of the release agent (wax) that can be used in the present invention include polyethylene wax, polypropylene wax, carnauba wax, rice wax, sazol wax, montan ester wax, Fischer-Tropsch wax, and paraffin wax. . When used for full-color toners for oilless fixing, those having a melting point of 60 to 100 ° C., preferably 70 to 90 ° C. can be suitably used. For example, fatty acid esters, low molecular weight polyethylene, carnauba wax, low melting point paraffins and the like can be used. Can be mentioned. A particularly preferred wax is a low melting paraffin having a low polarity and a high mold release effect. In particular, in a color toner for oilless fixing, it is necessary to use a release agent as an essential component. When the softening point of the wax is lower than 60 ° C., the effect of improving the high temperature offset property is lowered. When the wax is higher than 100 ° C., the dispersion in the binder resin is insufficient, and filming on the photoconductor is likely to occur. Further, the amount added to the toner is preferably in the range of 3.5 to 10 wt%, preferably 4 to 8 wt% in the pulverized toner. If it is less than 3.5 wt%, the releasing effect is not exhibited, and if it exceeds 10 wt%, free wax is likely to be generated due to poor wax dispersion during melt-kneading, and filming problems are likely to occur. On the other hand, in the toner by the wet granulation method, it is relatively easy to control the placement of the wax in the toner, such as encapsulation, and there is a margin for the poor dispersion of the wax and the generation of free wax with respect to the pulverized toner. It is possible to increase the addition amount to 5 to 12 wt%.

  As the colorant used in the present invention, known pigments and dyes can be used and are not particularly limited. For example, carbon black, aniline blue, calcoil blue, chrome yellow, ultramarine blue, DuPont oil red, quinoline yellow, methylene blue chloride, copper phthalocyanine, malachite green oxalate, lamp black, rose bengal, C.I. I. Pigment red 48: 1, C.I. I. Pigment red 122, C.I. I. Pigment red 57: 1, C.I. I. Pigment red 184, C.I. I. Pigment red 269, C.I. I. Pigment red 150, C.I. I. Pigment red 146, C.I. I. Pigment yellow 97, C.I. I. Pigment yellow 12, C.I. I. Pigment yellow 17, C.I. I. Solvent Yellow 162, C.I. I. Pigment yellow 180, C.I. I. Pigment yellow 93, C.I. I. Pigment yellow 185, C.I. I. Pigment yellow 74, C.I. I. Pigment yellow 155, C.I. I. Pigment blue 15: 1, C.I. I. And CI Pigment Blue 15: 3. When the colorant is used for the color toner, it is preferable to use a colorant obtained by highly dispersing the colorant in the binder resin in advance by a master batch process or a flushing process. The content of the colorant is preferably 2 to 15 parts by weight with respect to 100 parts by weight of the binder resin.

  It is also possible to add an additive such as a charge control agent to the toner base particles as necessary. Examples of the charge control agent for negatively charged toner include chromium complex type azo dyes S-32, 33, 34, 35, 37, 38, 40 (manufactured by Orient Chemical Co., Ltd.), Eisenspiron Black TRH, BHH (Hodogaya). Chemical Co., Ltd.), Kaya Set Black T-22, 004 (Nippon Kayaku Co., Ltd.), Copper Phthalocyanine Dye S-39 (Orient Chemical Industries), Chromium Complex E-81, 82 (Orient Chemical Industries) Zinc complex salt E-84 (manufactured by Orient Chemical Industry Co., Ltd.), aluminum complex salt E-86 (manufactured by Orient Chemical Industry Co., Ltd.), boron complex salt LR-147 (manufactured by Nippon Carlit Co., Ltd.) consisting of benzylic acid derivatives, calixarene compounds, etc. Can be used. Further, as the negative charge control agent used for the full color toner, a colorless, white or light color charge control agent which does not adversely affect the color tone and translucency of the color toner can be used. For example, a salicylic acid derivative zinc or chromium metal complex , Calixarene compounds, organoboron compounds composed of benzylic acid derivatives, fluorine-containing quaternary ammonium salt compounds, and the like are preferably used. Examples of the salicylic acid metal complex include those described in JP-A Nos. 53-127726 and 62-145255, and examples of calixarene compounds include those described in JP-A No. 2-201378. However, as the organic boron compound, for example, those described in JP-A-2-221967 can be used, and as the organic boron compound, for example, those described in JP-A-3-1162 can be used.

As a method for producing the toner base particles, a known production method can be used. Examples thereof include a dry pulverization method, a wet emulsion polymerization, a suspension polymerization, and a dissolution suspension (emulsion granulation) method. In general, irregular particles can be obtained in the case of the pulverization method, and spherical particles can be obtained in the case of the wet method, and a toner manufacturing method suitable for the image forming process may be used. The toner base particles preferably have a small particle size from the viewpoint of image quality, and those having a volume average particle size of about 4 μm to 10 μm can be suitably used. Particularly in the present invention, it is preferable to use toner base particles having a volume average diameter of 4 to 9 μm.

<< Pulverized toner >>
In the case of producing a toner by a pulverization method, according to a conventionally known means, a step of mechanically mixing a binder resin and a wax (including a case where they are internally added to the binder resin) and a toner component of a colorant, A toner manufacturing method having a melt kneading step, a pulverizing step, and a classification step can be applied. In addition, in the mechanical mixing step and the melt-kneading step, a production method is also included in which powder other than the particles obtained as a product obtained in the pulverization or classification step is returned and reused.

<< Emulsion polymerization association toner >>
When producing a toner by the emulsion polymerization association method, at least wax is dissolved or dispersed in a vinyl monomer, and the wax is internally added to the vinyl resin dispersion by a method such as miniemulsion polymerization. It can be isolated by associating and fusing together with a vinyl resin dispersion, a pigment dispersion, etc. to obtain a toner slurry, and then collecting it by washing and filtration according to known methods and drying.
In this production method, shape controllability is high, and it is possible to control the shape relatively freely in the range from potato to true sphere, but a large amount of additives such as surfactants and flocculants are added in the aqueous system. In addition, since it is a granulation technique, there is a problem that the chargeability is remarkably inferior.

<< Dissolution suspension (extension) method >>
This is a toner manufacturing method obtained by dispersing and granulating oil droplets of an organic solvent in which a toner composition containing a polymer is dissolved in an aqueous medium. In recent years, the dissolution has been further improved in controlling the molecular weight and controlling the structure of the toner. A suspension extension method is proposed in Japanese Patent Application Laid-Open No. 2004-139003. In this production method, oil droplets of an organic solvent in which a toner composition containing a prepolymer is dissolved are dispersed in an aqueous medium to obtain particles formed by an extension reaction and / or a crosslinking reaction.
According to this production method, it is possible to use a polyester resin that could not be used in the emulsion polymerization method or suspension polymerization method, and it is possible to produce a full-color toner having particularly excellent fixing characteristics. Further, the molecular weight on the polymer side can be easily controlled by the prepolymer extension reaction by the urethane / urea bond, which is suitable for the production of a full color toner for oilless fixing.
However, since the urethane / urea bond is used for the extension of the prepolymer in the present production method, there is a problem that image noise such as fog is likely to be generated because of the low negative chargeability when used in the one-component development method.

As a method for externally adding the inorganic particles of the present invention to the toner base particles obtained as described above, a dry mixing method using a mixer such as a Henschel mixer is preferable. Further, after the treatment, it is preferable to pass through a sieve having an opening of 100 μm or less from the viewpoint of removing foreign substances.
The toner of the present invention can be obtained by externally adding the inorganic particles A, B and C to the toner base particles and mixing them. The addition amount of the inorganic particles in the present invention is preferably adjusted so as to be within the above specified range.
The toner of the present invention can be used as a known electrophotographic toner regardless of whether it is monochrome, color, one component, or two components. In particular, the contact charging method, blade cleaning method, and oilless fixing can be used. It is suitable for use in a full-color image forming method having a method.

<Configuration of image forming method>
1 shows an example of a developing device configuration to which the present invention can be applied. In addition, this structure is an example and is not limited to this.
As the developing roller, a roller coated with an elastic rubber layer is used, and a surface coat layer made of a material that is easily charged to a polarity opposite to that of the toner is provided on the surface. The elastic rubber layer is set to a hardness of 60 degrees or less according to JIS-A in order to prevent toner deterioration due to pressure concentration at the contact portion with the layer regulating member. The surface roughness Ra is set to 0.3 to 2.0 μm, and a necessary amount of toner is held on the surface. Since the developing roller is applied with a developing bias for forming an electric field between the developing roller and the photosensitive member, the elastic rubber layer is set to have a resistance value of 10 ³ to 10 ¹⁰ Ω. The developing roller rotates in the clockwise direction, and conveys the toner held on the surface to a position facing the layer regulating member and the photoconductor.

The layer regulating member is provided at a position lower than the contact position between the supply roller and the developing roller. The layer regulating member is made of a metal leaf spring material such as SUS or phosphor bronze, and the free end is brought into contact with the surface of the developing roller with a pressing force of 10 to 40 N / m. The film is thinned and charged by frictional charging. Further, a regulation bias having a value offset in the same direction as the toner charging polarity with respect to the developing bias is applied to the layer regulating member in order to assist frictional charging.
The rubber elastic body constituting the surface of the developing roller is not particularly limited. For example, styrene-butadiene copolymer rubber, acrylonitrile-butadiene copolymer rubber, acrylic rubber, epichlorohydrin rubber, urethane rubber, silicon rubber, A blend of two or more of these may be mentioned. Among these, a blend rubber of epichlorohydrin rubber and acrylonitrile-butadiene copolymer rubber is preferably used.
The developing roller used in the present invention is manufactured, for example, by covering the outer periphery of a conductive shaft with a rubber elastic body. The conductive shaft is made of a metal such as stainless steel, for example.

<Configuration of charging process in electrostatic latent image holder>
As shown in FIG. 1, as a charging member used in the charging step of the present invention, a cored bar (3), a conductive layer (5) is coated on the cored bar (3), and this conductive layer (5) is coated. The surface layer (6) is formed, and is formed in a cylindrical shape as a whole. The voltage applied to the core metal (3) by the power source (7) is applied to the latent image carrier (1) via the conductive layer (5) and the surface layer (6), and the surface of the latent image carrier (1) Is to be charged.
The cored bar (3) of the charging member (2) is disposed along the longitudinal direction of the latent image carrier (1) (parallel to the axis of the latent image carrier (1)), and the charging member (2) The whole is pressed against the latent image carrier (1) with a predetermined pressing force. As a result, a part of the surface of the latent image carrier (1) and a part of the surface of the charging member (2) are brought into contact with each other along the longitudinal direction to form a contact nip having a predetermined width. The latent image carrier (1) is rotationally driven by a driving means (not shown), and the charging member (2) is configured to be driven and rotated accordingly.
In FIG. 1, the exposure unit, the developing unit, the transfer unit, and the cleaning unit are omitted.

The latent image carrier (1) is charged by the power source (7) through the vicinity of the contact nip. Through the contact nip, the surface of the charging member (2) and the charged area (corresponding to the length of the charging member (2)) on the surface of the latent image carrier (1) are in contact with each other. The charged area on the surface of the carrier (1) is uniform.
The conductive layer (5) of the charging member (2) is a non-metal (conductive vulcanized rubber in this example), and a low-hardness material is used to stabilize the contact state with the latent image carrier (1). It can be preferably used. For example, resins such as polyurethane, polyether, and polyvinyl alcohol, and rubbers such as hydrin, EPDM, and NBR are used. Examples of the conductive material include carbon black, graphite, titanium oxide, and zinc oxide.
The surface layer (6) is made of a material having a resistance value of medium resistance (10 ² to 10 ¹⁰ Ω) (in this example, acetylene black-containing polyurethane-silicon acrylic polymer).

For example, nylon, polyamide, polyimide, polyurethane, polyester, silicon, Teflon (registered trademark), polyacetylene, polypyrrole, polytheophene, polycarbonate, polyvinyl, etc. can be used as the resin, but fluorine is used to increase the contact angle with water. It is preferable to use a series resin.
Examples of the fluorine-based resin include polyvinylidene fluoride, polyvinyl fluoride, vinylidene fluoride-tetrafluoroethylene copolymer, and vinylidene fluoride-tetrafluoroethylene-hexafluoropropylene copolymer.

Furthermore, for the purpose of adjusting to a medium resistance, a conductive material such as carbon black, graphite, titanium oxide, zinc oxide, tin oxide, or iron oxide may be added as appropriate.
FIG. 2 is a perspective view showing an example of the image forming method of the present invention. In this image forming system, the image carrier (photosensitive member: 11) rotates in the direction of the arrow from below to above. The conveying member (developing roller: 13) of the developing device (12) contacts the image carrier (photosensitive member: 11) or holds a gap of about 0.1 to 0.3 mm and is driven as indicated by an arrow.
The material of the conveying member (developing roller: 13) is composed of a metal conductor such as aluminum or stainless steel having a suitable surface roughness by sandblasting. A supply member (toner supply roller: 14) is attached around the conveying member (developing roller: 13), a rubber plate (urethane rubber, silicon rubber, etc.) is attached to the leaf spring material, or a restriction blade made of a metal material such as SUS ( A toner layer thickness regulating blade (15) is arranged.
A toner feed shaft (16) is rotatably disposed in a holding chamber (17) for holding toner for supplying toner to a supply member (toner supply roller: 14).

A method for analyzing the toner and constituent materials used in the present invention will be described below.
<< Inorganic particle size >>
The number average particle size of the inorganic particles of the present invention is measured by a laser diffraction / scattering particle size distribution analyzer LA-920 (manufactured by Horiba, Ltd.). The inorganic particles are ultrasonically dispersed in advance in an aqueous medium to which a surfactant is added, and the obtained sample is measured with this measuring machine.
<< Specific surface area of inorganic particles >>
The BET specific surface area of the inorganic particles of the present invention is determined by the BET multipoint method using a specific surface area meter auto soap 1 manufactured by QUANTACHROME.

<< Dispersed particle size of inorganic particles >>
The dispersed particle diameter of the inorganic particles on the toner surface in the present invention was calculated from an SEM observation image. Specifically, the observation was performed a plurality of times with one toner particle in the field of view at a magnification of 20,000 times, and the dispersed particle diameter (aggregated particle diameter) and the number frequency of 500 toner surfaces were represented in a histogram. Calculated as the number median diameter. This calculation can also be performed by analysis using a commercially available image processing apparatus (for example, Luzex (manufactured by Nireco)).
Further, in the examples of the present invention, in order to use together with external additives other than the inorganic particles of the present invention, the central metal element of the metal soap surface-treated on the inorganic particles is mapped by EPMA, and from the mapped image of the present invention, The dispersed particle size of the inorganic particles was calculated.
<< Toner softening point (hereinafter also referred to as T1 / 2) >>
T1 / 2 and outflow end temperature are values measured by a flow tester CFT-500D manufactured by Shimadzu Corporation. The diameter of the extrusion port was 0.5 mm, the depth was 1 mm, and the temperature was raised at 3 ° C./min.
The load applied to the sample was set to 30 kgf.

<< Glass transition point, wax melting point >>
The differential scanning calorimeter (DSC) uses a DSC6200 manufactured by Seiko Instruments Inc., heated up to 200 ° C., and cooled from the temperature to 0 ° C. at a cooling rate of 10 ° C./min. Measured in minutes. This analysis calculates the glass transition point of the resin and toner and the melting point of the wax.
<< Measurement of acid value >>
The acid value was measured according to JIS K-0070. The specific operation procedure is as follows.
(1) A sample is put into a 300 ml beaker, and 150 ml of a mixed solution of toluene / ethanol (4/1: v / v) is added and dissolved.
(2) Titrate with a potentiometric titrator using an ethanol solution of 0.1 mol / l KOH. For example, automatic titration using a potentiometric titrator AT-400 (win workstation) manufactured by Kyoto Electronics Co., Ltd. and an ABP-410 electric burette can be used. (3) The amount of KOH solution used at this time is set to Sml, and a blank is measured at the same time, and the amount of KOH solution used at this time is set to Bml.
(4) The acid value is calculated by the following formula. f is a factor of KOH.
Acid value (mgKOH / g) = {(SB) × f × 5.61} / W

<< Toner particle size >>
Measurement of the particle diameter of the toner particles is performed by a Coulter counter method.
Examples of the measurement device for the particle size distribution of toner particles by the Coulter counter method include Coulter Counter TA-II, Coulter Multisizer II, and Coulter Multisizer III (all manufactured by Coulter). The measurement method will be described below.
First, 0.1 to 5 ml of a surfactant (preferably alkylbenzene sulfonate) is added as a dispersant to 100 to 150 ml of an aqueous electrolytic solution. Here, the electrolytic solution is a solution prepared by preparing a 1% NaCl aqueous solution using first grade sodium chloride. For example, ISOTON-II (manufactured by Coulter) can be used. Here, 2 to 20 mg of the measurement sample is further added as a solid content. The electrolytic solution in which the sample is suspended is subjected to a dispersion treatment with an ultrasonic disperser for about 1 to 3 minutes. Volume distribution and number distribution are calculated. From the obtained distribution, the weight average particle diameter (Dv) and the number average particle diameter (Dn) of the toner can be obtained.

<< Toner circularity >>
As a method for measuring the shape, an optical detection band method is suitable in which a suspension containing particles is passed through an imaging unit detection band on a flat plate, and a particle image is optically detected and analyzed by a CCD camera. A toner having an average circularity of 0.960 or more, which is a value obtained by dividing the perimeter of an equivalent circle having the same projected area obtained by this method by the perimeter of the actual particles, has a high density reproducibility with a proper density reproducibility. It was found to be effective in forming. More preferably, the average circularity is 0.980 to 1.000. This value is a value measured as an average circularity by a flow type particle image analyzer FPIA-2000. As a specific measuring method, 0.1 to 0.5 ml of a surfactant, preferably alkylbenzene sulfonate is added as a dispersant to 100 to 150 ml of water from which impure solids have been removed in advance, and further measurement is performed. Add about 0.1-0.5g of sample. The suspension in which the sample is dispersed is obtained by performing dispersion treatment for about 1 to 3 minutes with an ultrasonic disperser and measuring the shape and distribution of the toner with the above apparatus at a dispersion concentration of 3000 to 10,000 / μl. .

  As described above, the latent image developing toner according to the present invention exhibits good chargeability by adopting the above-described configuration in the step of charging by contacting the latent image holding member. In addition, adhesion to the surface of the charging member or the surface of the photosensitive drum and generation of scratches are extremely unlikely, the matching of the contact charging process according to the present invention is very good, the ability of the charging process is fully exhibited, and good image formation is always performed. Toner could be provided.

Next, the present invention will be described in more detail with reference to examples. However, the present invention is not limited to the following examples. In the examples, all parts represent parts by weight.
Production of Composite Oxide Particle C A slurry of Mg (OH) ₂ powder and SiO ₂ powder (average primary particle size 0.02 μm) were weighed to 2: 1 with MgO: SiO ₂ (molar ratio), and MgO A slurry of 150 L with a concentration of 71.5 g / L and a SiO ₂ concentration of 53.3 g / L was used. Using a sand grinder mill, 0.8 mmφ alumina silica beads were used as the media, the media filling rate was 80%, and the liquid feed rate was 4. Wet pulverization was performed under the conditions of 0 L / min and the number of slurry passes of 3 passes. The slurry was spray-dried with a spray dryer and fired at 1100 ° C. for 30 minutes in the air in an electric furnace.
Then, the fired product is slurried to 300 g / L, 50 L is sand grinder mill, 0.8 mmφ alumina silica-based beads are used as media, the media filling rate is 80%, and the liquid feeding speed is 5.6 L / The wet pulverization was performed under the conditions of min and the number of slurry passes of 2 passes. The slurry was spray-dried with a spray dryer and pulverized with a sand mill to obtain particles C-1. When the powder obtained as described above was identified by X-ray diffraction, it was a single phase of forsterite. The average primary particle size was 0.10 μm, the specific surface area was 18.9 m ² / g, and the average secondary particle size was 0.39 μm.
Except having performed the calcination temperature of the said process at 1200 degreeC, it created similarly to C-1 and obtained particle | grains C-2. When the powder obtained as described above was identified by X-ray diffraction, it was a single phase of forsterite. The average primary particle size was 0.15 μm, the specific surface area was 10.5 m ² / g, and the average secondary particle size was 1.7 μm.
Particles were prepared in the same manner except that the slurry was weighed to have a MgO: SiO ₂ (molar ratio) ratio of 1: 1 and a slurry of 150 L with a MgO concentration of 35.8 g / L and a SiO ₂ concentration of 53.3 g / L. C-3 was obtained. When the powder obtained as described above was identified by X-ray diffraction, it was a single phase of enstatite. The average primary particle size was 0.09 μm, the specific surface area was 20.5 m ² / g, and the average secondary particle size was 0.40 μm.

Preparation of pulverized toner particles << Preparation of first binder resin H1 >>
As vinyl monomer,
Styrene 600g
110 g of butyl acrylate
Acrylic acid 30g
Dicumyl peroxide 30g as a polymerization initiator
Was placed in a dropping funnel.
Among polyester monomers, as polyol,
1230 g of polyoxypropylene (2.2) -2,2-bis (4-hydroxyphenyl) propane
290 g of polyoxyethylene (2.2) -2,2-bis (4-hydroxyphenyl) propane
250g of isododecenyl succinic anhydride
Terephthalic acid 310g
180 g of 1,2,4-benzenetricarboxylic anhydride
Dibutyltin oxide 7g as esterification catalyst
Into a 5-liter four-necked flask equipped with a thermometer, stainless steel stirrer, flow-down condenser and nitrogen inlet tube, and vinyl from the dropping funnel while stirring at a temperature of 160 ° C. in a nitrogen atmosphere in a mantle heater. A mixed solution of a monomer monomer and a polymerization initiator was added dropwise over 1 hour. The addition polymerization reaction was aged for 2 hours while maintaining the temperature at 160 ° C., and then the temperature was raised to 230 ° C. to perform the condensation polymerization reaction. The degree of polymerization was tracked by the softening point measured using a constant load extrusion capillary rheometer, and when the desired softening point was reached, the reaction was terminated to obtain the first binder resin H1.
The softening point (T1 / 2) of the obtained first binder resin H1 was 130 ° C.

≪Creation of second binder resin L1≫
Regarding the second binder resin L1, a polyester resin was synthesized by adding the following monomers in the same manner as the first binder resin H1, except that no vinyl monomer or wax was added.
1650 g of polyoxypropylene (2.2) -2,2-bis (4-hydroxyphenyl) propane
660 g of polyoxyethylene (2.2) -2,2-bis (4-hydroxyphenyl) propane
190g of isododecenyl succinic anhydride
750g terephthalic acid
190 g of 1,2,4-benzenetricarboxylic anhydride
Dibutyltin oxide 0.3g as an esterification catalyst
The second binder resin L1 thus obtained had a softening point (T1 / 2) of 113 ° C.

<Creation of toner base particles (pulverization method)>
30 parts of first binder resin H1
70 parts of second binder resin L1
Paraffin wax, melting point 73.3 ° C. 5 parts Colorant (copper phthalocyanine blue pigment) 2.5 parts
The above materials were sufficiently mixed in a blender, then kneaded in a pressure kneader, cooled, pulverized and classified to obtain a cyan base toner (ii) having a volume average particle size of about 7.0 μm.
The acid value of the toner (a) was measured, and found to be 22.4 KOH mg / g, T1 / 2 was 120 ° C., and the circularity was 0.922.

Preparation of emulsion polymerization toner particles <Cyan colorant dispersion>
Pigment C.I. I. Pigment Blue 15: 3 50 parts by weight
10 parts by weight of sodium dodecyl sulfate
200 parts by weight of ion exchange water
The above was dispersed with a sand grinder mill to obtain a cyan colorant dispersion having a volume average particle diameter (D50) of 170 nm.

<Preparation of latex>
(Preparation of latex 1L)
(Dispersion medium)
4.05 g sodium dodecyl sulfate
Ion exchange water 2500g
The above dispersion medium is charged into a 5000 ml separable flask equipped with a stirrer, a temperature sensor, a cooling pipe, and a nitrogen introducing device, and the temperature in the flask is raised to 80 ° C. while stirring at a stirring speed of 230 rpm under a nitrogen stream. I let you.
Styrene 612g
156 g of n-butyl acrylate
Methacrylic acid 32g
n-Octyl mercaptan 13g
To this activator solution, an initiator solution prepared by dissolving 9.62 g of a polymerization initiator (potassium persulfate) in 200 g of ion-exchanged water is added, and the monomer solution is added dropwise over 90 minutes. Polymerization (first stage polymerization) was performed by heating and stirring at 80 ° C. for 2 hours to prepare a latex. This is referred to as “latex (1 L)”. The T1 / 2 of the dried latex (1 L) was 124 ° C.

(Preparation of latex 1HML)
(1) Preparation of core particles (first stage polymerization)
(Dispersion medium 1)
4.05 g sodium dodecyl sulfate
Ion exchange water 2500.00g
The dispersion medium 1 was charged into a 5000 ml separable flask equipped with a stirrer, temperature sensor, cooling pipe, and nitrogen introducing device, and the temperature in the flask was raised to 80 ° C. while stirring at a stirring speed of 230 rpm under a nitrogen stream. Allowed to warm.
Styrene 568.00 g
n-Butyl acrylate 164.00g
Methacrylic acid 68.00 g
n-octyl mercaptan 16.51 g
To this activator solution, an initiator solution prepared by dissolving 9.62 g of a polymerization initiator (potassium persulfate) in 200 g of ion-exchanged water is added, and the monomer solution is added dropwise over 90 minutes. Polymerization (first stage polymerization) was performed by heating and stirring at 80 ° C. for 2 hours to prepare a latex. This is referred to as “latex (1H)”. The weight average particle diameter of the latex (1H) was 68 nm.

(2) Formation of intermediate layer (second stage polymerization)
(Monomer solution 2)
Styrene 123.81g
n-butyl acrylate 39.51 g
Methacrylic acid 12.29g
n-octyl mercaptan 0.72 g
75.0 g paraffin wax
In a flask equipped with a stirrer, the monomer solution 2 described above was charged, and heated to 80 ° C. and dissolved to prepare a monomer solution.
(Dispersion medium 2)
_{C 10 H 21 (OCH 2 CH} 2) 2 OSONa 0.60g
Ion exchange water 2700.00g
On the other hand, after the dispersion medium 2 is heated to 98 ° C. and 32 g of the latex (1H), which is a dispersion medium of core particles, is added to the dispersion medium in terms of solid content, a mechanical disperser “CLEA” having a circulation path is added. The monomer solution 2 was mixed and dispersed for 8 hours by “CLEARMIX” (manufactured by M Technique Co., Ltd.) to prepare a dispersion (emulsion) containing emulsified particles (oil droplets).
Next, an initiator solution prepared by dissolving 6.12 g of a polymerization initiator (potassium persulfate) in 250 ml of ion-exchanged water is added to this dispersion (emulsion), and this system is heated and stirred at 82 ° C. for 12 hours. Thus, polymerization (second stage polymerization) was performed to obtain latex (a dispersion of composite resin particles having a structure in which the surface of latex (1H) particles was coated). This is referred to as “latex (1HM)”.

(3) Formation of outer layer (third stage polymerization)
(Monomer solution 3)
Styrene 350g
95 g of n-butyl acrylate
Methacrylic acid 5g
n-octyl mercaptan 6.1 g
An initiator solution in which 8.8 g of a polymerization initiator (KPS) is dissolved in 350 ml of ion exchange water is added to the latex (1HM) obtained as described above, and the monomer solution is subjected to a temperature condition of 82 ° C. Solution 3 was added dropwise over 1 hour. After completion of the dropping, polymerization (third stage polymerization) was performed by heating and stirring for 2 hours, followed by cooling to 28 ° C. and an intermediate layer made of latex (latex (1H) and a second stage polymerization resin). And an outer layer made of a third-stage polymerization resin, and a dispersion of a composite resin in which wax is contained in the second-stage polymerization resin layer). This latex is referred to as “latex (1HML)”. The amount of the wax W1 charged in the latex (1HML) was 12.5% by mass relative to the monomer, and the T1 / 2 of the dried latex (1HML) was measured and found to be 131 ° C.

<Preparation of emulsion polymerization toner particles>
240.0 g (converted to solid content) of latex (1 L), 180.0 g (converted to solid content) of latex (1 HML), 900 g of ion-exchanged water, and 150 g of the cyan colorant dispersion, a temperature sensor, cooling The mixture was stirred in a reaction vessel (four-necked flask) equipped with a tube, a nitrogen introducing device, and a stirring device. After adjusting the temperature in a container to 30 degreeC, 5N sodium hydroxide aqueous solution was added to this solution, and pH was adjusted to 8-10.0.
Next, an aqueous solution in which 65.0 g of magnesium chloride hexahydrate was dissolved in 1000 ml of ion-exchanged water was added over 10 minutes at 30 ° C. with stirring. After standing for 3 minutes, the temperature was raised to 92 ° C. to produce aggregated particles. In this state, the particle size of the aggregated particles was measured with “Coulter Counter TA-II”. When the number average particle size reached 6.6 μm, an aqueous solution in which 80.4 g of sodium chloride was dissolved in 1000 ml of ion-exchanged water. Was added to stop the particle growth, and as a ripening treatment, the mixture was heated and stirred at a liquid temperature of 94 ° C. to continue fusing of the particles and phase separation of the crystalline substance (ripening step). In this state, the shape of the fused particles was measured with a flow type particle image analyzer “FPIA-2000”. When the shape factor reached 0.952, the mixture was cooled to 30 ° C. and stirring was stopped. The produced fused particles were filtered, repeatedly washed with ion exchange water at 45 ° C., and then dried with hot air at 40 ° C. to obtain toner (b). When the number average particle diameter and the shape factor of the toner (b) were measured again, they were 6.5 μm and 0.954, respectively.
Further, the acid value of the toner was measured and found to be 25.1 KOHmg / g, and T1 / 2 by a constant load extrusion capillary rheometer was 127 ° C.

◎ Preparation of dissolution suspension extension method toner particles (synthesis of organic fine particle emulsion)
In a reaction vessel equipped with a stirrer and a thermometer, 683 parts of water, 11 parts of sodium salt of ethylene oxide methacrylate adduct sulfate (Eleminol RS-30, manufactured by Sanyo Chemical Industries), 83 parts of styrene, 83 parts of methacrylic acid, When 110 parts of butyl acrylate and 1 part of ammonium persulfate were charged and stirred at 3800 rpm for 30 minutes, a white emulsion was obtained. The system was heated to raise the system temperature to 75 ° C. and reacted for 4 hours. Further, 30 parts of a 1% ammonium persulfate aqueous solution was added, and the mixture was aged at 75 ° C. for 6 hours, and then an aqueous vinyl resin (a copolymer of styrene-methacrylic acid-butyl acrylate-methacrylic acid ethylene oxide adduct sulfate sodium salt). A dispersion [fine particle dispersion 1] was obtained. The volume average particle size of the [fine particle dispersion 1] measured with a laser diffraction / scattering particle size distribution analyzer LA-920 was 110 nm. A portion of [Fine Particle Dispersion 1] was dried to isolate the resin component. The Tg of the resin was 58 ° C., and the weight average molecular weight was 130,000.

(Adjustment of aqueous phase)
990 parts of water, 83 parts of [fine particle dispersion 1], 37 parts of a 48.3% aqueous solution of dodecyl diphenyl ether disulfonate (Eleminol MON-7): Sanyo Chemical Industries) and 90 parts of ethyl acetate were mixed and stirred. A liquid was obtained. This is designated [Aqueous Phase 1].
(Synthesis of low molecular weight polyester)
In a reaction vessel equipped with a condenser, a stirrer and a nitrogen inlet tube, 229 parts of bisphenol A ethylene oxide 2-mole adduct, 529 parts of bisphenol A propylene oxide 3-mole adduct, 208 parts terephthalic acid, 46 parts adipic acid and dibutyl Put 2 parts of tin oxide, react at normal pressure and 230 ° C for 7 hours, and further react at 5-15 hours under reduced pressure of 10 to 15 mmHg, then put 44 parts of trimellitic anhydride into the reaction vessel, 180 ° C, normal pressure For 3 hours to obtain [Low molecular weight polyester 1]. [Low molecular polyester 1] had a number average molecular weight of 2300, a weight average molecular weight of 6700, a Tg of 43 ° C., and an acid value of 25.
(Synthesis of intermediate polyester)
In a reaction vessel equipped with a cooling pipe, a stirrer and a nitrogen introduction pipe, 682 parts of bisphenol A ethylene oxide 2-mole adduct, 81 parts of bisphenol A propylene oxide 2-mole adduct, 283 parts of terephthalic acid, trimellitic anhydride 22 And 2 parts of dibutyltin oxide were added, reacted at normal pressure and 230 ° C. for 7 hours, and further reacted at reduced pressure of 10 to 15 mmHg for 5 hours to obtain [Intermediate Polyester 1]. [Intermediate Polyester 1] had a number average molecular weight of 2200, a weight average molecular weight of 9700, Tg of 54 ° C., an acid value of 0.5, and a hydroxyl value of 52.
Next, 410 parts of [Intermediate polyester 1], 89 parts of isophorone diisocyanate, and 500 parts of ethyl acetate are placed in a reaction vessel equipped with a cooling pipe, a stirrer, and a nitrogen introduction pipe, and reacted at 100 ° C. for 5 hours. Polymer 1] was obtained. [Prepolymer 1] had a free isocyanate weight% of 1.53%.

(Synthesis of ketimine)
In a reaction vessel equipped with a stirrer and a thermometer, 170 parts of isophoronediamine and 75 parts of methyl ethyl ketone were charged and reacted at 50 ° C. for 4 and a half hours to obtain [ketimine compound 1]. The amine value of [ketimine compound 1] was 417.
(Synthesis of master batch (MB))
1200 parts of water, 540 parts of carbon black (made by Printex 35 Dexa) [DBP oil absorption = 42 ml / 100 mg, pH = 9.5] and 1200 parts of polyester resin are added and mixed with a Henschel mixer (made by Mitsui Mining Co., Ltd.). After kneading at 130 ° C. for 1 hour using two rolls, rolling and cooling and pulverizing with a pulverizer, [Masterbatch 1] was obtained.

(Production of oil phase)
378 parts of [Low molecular weight polyester 1], 100 parts of carnauba wax, and 947 parts of ethyl acetate were charged in a container equipped with a stirring bar and a thermometer, heated to 80 ° C. with stirring, and maintained at 80 ° C. for 5 hours. Cooled to 30 ° C. in 1 hour. Next, 500 parts of [Masterbatch 1] and 500 parts of ethyl acetate were charged in a container and mixed for 1 hour to obtain [Raw material solution 1].
[Raw material solution 1] 1324 parts are transferred to a container, and using a bead mill (Ultra Visco Mill, manufactured by Imex Co., Ltd.), a liquid feeding speed of 1 kg / hr, a disk peripheral speed of 6 m / sec, and 0.5 mm zirconia beads are 80% by volume. Carbon black and WAX were dispersed under conditions of filling and 3 passes. Next, 1324 parts of a 65% ethyl acetate solution of [low molecular weight polyester 1] was added, followed by two passes with a bead mill under the above conditions to obtain [Pigment / WAX Dispersion 1]. The solid content concentration of [Pigment / WAX Dispersion 1] (130 ° C., 30 minutes) was 50%.

(Emulsification → Desolvation)
[Pigment / WAX Dispersion 1] 749 parts, [Prepolymer 1] 115 parts, [Ketimine Compound 1] 2.9 parts in a container and TK homomixer (manufactured by Tokushu Kika) at 5,000 rpm for 2 minutes After mixing, 1200 parts of [Aqueous phase 1] was added to the container, and mixed with a TK homomixer at 13,000 rpm for 25 minutes to obtain [Emulsion slurry 1].
[Emulsion slurry 1] was put into a container equipped with a stirrer and a thermometer, and after removing the solvent at 30 ° C. for 8 hours, aging was carried out at 45 ° C. for 7 hours to obtain [Dispersion slurry 1].

(Washing → drying)
[Dispersion Slurry 1] After filtering 100 parts under reduced pressure,
(1): Add 100 parts of ion-exchanged water to the filter cake and mix with a TK homomixer (rotation speed: 1)
And filtered at 2,000 rpm for 10 minutes).
(2): 100 parts of a 10% aqueous sodium hydroxide solution was added to the filter cake of (1), mixed with a TK homomixer (30 minutes at 12,000 rpm), and then filtered under reduced pressure.
(3): 100 parts of 10% hydrochloric acid was added to the filter cake of (2), mixed with a TK homomixer (rotation speed: 12,000 rpm for 10 minutes), and then filtered.
(4): Add 300 parts of ion-exchanged water to the filter cake of (3), mix with a TK homomixer (10 minutes at 12,000 rpm) and then filter twice to obtain [Filter cake 1]. It was.
[Filter cake 1] was dried at 45 ° C. for 48 hours with a circulating dryer, and sieved toner base particles (C) were obtained with an opening of 75 μm mesh. The softening point of the toner (c) was 108 ° C.

<Production of Toners of Examples and Comparative Examples>
As shown in Table 2, together with the external additives shown in Table 1, each external additive and inorganic particles are added to the toner base particles, mixed with a Henschel mixer, and sieved with a vibration sieve to obtain each toner. It was.

<Evaluation>
The developer obtained in each Example and Comparative Example was evaluated according to the following method for each evaluation item.
<Development noise>
When each toner is set in a tandem full color printer IPSiO CX-3000 (manufactured by Ricoh) using a contact charging roller system and a non-magnetic one-component developing system, and 8000 sheets are continuously printed using an image chart with a printing rate of 15%. Evaluation was made on the occurrence of image background contamination, developing roller filming, streaks, etc. due to poor charging.
A: No soiling, filming, streaks, or thin layer formation failure occurred.
◯: Some of background contamination, filming, streaks, or thin layer formation was slightly occurring, but the level was not problematic in practical use.
(Triangle | delta): Any of background stain | pollution | contamination, filming, a stripe | line | column, and thin layer formation defect generate | occur | produced, and it was the level which becomes a problem practically.
×: Many of ground stain, filming, streaks, and thin layer formation failure occurred.

<Cleanability>
The same evaluation as the above evaluation was performed, and the state of occurrence of uncleaned cleaning on the photoconductor after printing 8000 sheets was evaluated.
○: No wiping residue due to poor cleaning occurred.
X: A wiping residue due to poor cleaning occurred.
<Photoconductor noise>
The same evaluation as the above evaluation was performed, and the occurrence of filming and streaks on the photoconductor after printing 8,000 sheets was evaluated.
○: Filming and streaks were not generated on the surface of the photoreceptor.
X: Filming and streaks were generated on the surface of the photoreceptor.
<Charging roller noise>
The same evaluation as the above evaluation was performed, and the occurrence of filming of the contact charging roller after printing 8000 sheets was evaluated.
○: Filming and charging failure of the photosensitive member did not occur on the surface of the charging roller.
X: Filming and photoconductor charging failure occurred on the surface of the charging roller.
<Transfer missing>
The same evaluation as the above evaluation was performed, and a fine line image after printing 8000 sheets was output to evaluate the occurrence of transfer loss.
○: Transfer deficiency was at a level causing no practical problem.
X: Omission in transfer occurred and was a level causing a problem in practical use.

The above evaluation results are shown in the following table together with the external additive conditions of each developer.

It is explanatory drawing of a structure of a charging member. FIG. 3 is an explanatory diagram of an image forming method of the present invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Latent image carrier 2 Charging member 3 Core metal 5 Conductive layer 6 Surface layer 7 Power source 11 Photoconductor 12 Developing device 13 Developing roller 14 Toner supply roller 15 Regulating blade 16 Toner feed shaft 17 Holding chamber

Claims (15)

Toner mother particles containing at least a colorant, a release agent and a binder resin, hydrophobic silica fine particles A having a number average particle diameter of 5 to 20 nm, hydrophobic titania having a number average particle diameter of 20 to 100 nm, and And / or fine particles B selected from silica and an average primary particle size of 0.01 to 0.5 μm, and an average secondary particle size formed by agglomeration of the primary particles is in the range of 0.02 to 2.0 μm. It is made of silica (SiO ₂ ) and magnesia (MgO), and the magnesia (MgO) / silica (SiO ₂ ) molar ratio is in the range of 0.8 to 2.2. enstatite, composite oxide particles C identified in any of steatite are externally added, the forsterite in the toner, less selected from the group consisting of enstatite and steatite Toner for developing electrostatic latent images which is characterized by also containing one.   2. The electrostatic latent image developing toner according to claim 1, wherein the composite oxide particles C have a number average particle diameter in the range of 0.02 to 2.0 [mu] m. The fine particles A and the particles B are hydrophobic, electrostatic latent image developing toner according to claim 1 or 2, characterized in that said hydrophobic hydration degree of 50 to 90.   The total addition amount of the fine particles A and the fine particles B is 2 to 5% by weight with respect to the toner base particles, and the addition amount of the composite oxide particles C is 0.3 to 5 with respect to the toner base particles. The toner for developing an electrostatic latent image according to any one of claims 1 to 3, wherein the toner for developing an electrostatic latent image is wt%. The weight ratio of the fine particles B and the fine particles A is 1: 9 to 7: electrostatic latent image developing toner according to any one of claims 1 to 4, characterized in that a 3. An electrostatic latent image developing toner according to any one of claims 1-5 having an average primary particle diameter of the composite oxide particles C is characterized in that it is a 0.02～0.15Myuemu. The electrostatic latent image developing toner according to claim 1, wherein the composite oxide particles C have an average secondary particle size of 0.1 to 2.0 μm. 2. The composite oxide particles C are obtained by sintering Mg (OH) ₂ powder or MgO powder and SiO ₂ powder having an average primary particle size of 10.0 μm or less. The toner for developing an electrostatic latent image according to any one of 7 to 7 . The toner base particles is in the range of volume average diameter 4～9Myuemu, electrostatic latent image developing toner according to any one of claims 1 to 8, characterized in that for use in a non-magnetic one-component developing method. The toner base particles is in the range of volume average diameter 4～9Myuemu, electrostatic latent image developing toner according to any one of claims 1 to 8, characterized in that for use in two-component developing method. Any of the toner mother particles is at least the releasing agent contained 3.5 to 10 wt%, claim 1-8, which is a toner for oilless fixing full color image forming comprising manufactured by grinding method The electrostatic latent image developing toner according to claim 1. The toner mother particles are at least releasing agent containing 5-12 weight%, claim 1-8, characterized in that a granulated toner for oilless fixing full color image forming comprising been manufactured in a wet The electrostatic latent image developing toner according to any one of the above. At least a rotatable image carrier, a charging step arranged in contact with the image carrier, and charging the image carrier to a predetermined potential, a rotating toner conveying member, and supplying toner to the conveying member an image forming method having a developing step comprising a toner supply member, an image forming method, wherein the toner is an electrostatic latent image developing toner according to any one of claims 1 to 12 . The toner is transferred to an electrostatic latent image formed on a photoreceptor to be visualized to form a toner image, and the toner image is transferred to a transfer material to form an image. A process cartridge configured to be detachable from the photoconductor, a charging unit that contacts the photoconductor to charge the photoconductor, and a latent image forming unit that forms an electrostatic latent image on the photoconductor Transfer means for transferring the toner image to a recording material; and at least one means selected from cleaning means for removing toner remaining on the photoreceptor after the toner image is transferred to the transfer material; A developing unit that develops toner on the electrostatic latent image formed on the photoconductor to form a toner image is integrally supported, and the toner is the static image according to any one of claims 1 to 12. Electro latent image development toner A process cartridge characterized by being a toner. In an image forming apparatus for forming an image by transferring a toner to an electrostatic latent image formed on a photoreceptor and visualizing it to form a toner image and transferring the toner image to a transfer material, the toner is claimed. Item 13. An image forming apparatus comprising the toner for developing an electrostatic latent image according to any one of Items 1 to 12 .

Images