JP5151384B2 - Negatively charged toner for developing electrostatic image, electrostatic image developer, toner cartridge, process cartridge, and image forming apparatus - Google Patents

Description

The present invention relates to a negatively charged toner for developing an electrostatic image, an electrostatic image developer, a toner cartridge, a process cartridge, and an image forming apparatus.

  In electrophotography, generally, a latent image is electrically formed on the surface of a photoconductor (image carrier) using a photoconductive substance by various means, and the formed latent image is replaced with toner. After developing the toner image to form a toner image, the toner image is transferred onto the surface of a transfer medium such as paper through an intermediate transfer member as necessary, and fixed by heating, pressurization, heat pressurization or the like. An image is formed through a plurality of processes. Further, the toner remaining on the surface of the photoreceptor is cleaned by various methods as necessary, and is used again for developing the toner image.

  As a fixing technique for fixing the toner image transferred to the surface of the transfer target, a heat roll for inserting and fixing the transfer target with the toner image transferred between a pair of rolls composed of a heating roll and a pressure roll The fixing method is common. As a similar technique, a fixing method in which one or both of the rolls is replaced with a belt is also known. Since these techniques are in direct contact with the image as compared with other fixing methods, a fast and robust image can be obtained and the energy efficiency is high.

  In recent years, with the increasing demand for energy saving required for image formation, in order to save power in a fixing process that occupies a certain amount of power consumption, and to expand the fixable temperature range, toner It has become necessary to lower the fixing temperature. By lowering the fixing temperature of the toner, in addition to the power saving and the expansion of the fixable temperature range, a waiting time until the fixable temperature of the surface of the fixing member such as a fixing roll at the time of power input, so-called There are significant advantages such as shortening the warm-up time and extending the life of the fixing member.

As a means for lowering the toner fixing temperature, a technique for lowering the glass transition temperature of the binder resin contained in the toner is generally performed. However, if the glass transition temperature is too low, powder aggregation (blocking) tends to occur, so it is important to achieve both low-temperature fixability and prevention of blocking.
As a means for improving the blocking resistance, there is a method of reducing the adhesion force between toners by using hydrophobized silica or titania. Of these hydrophobized external additives, silica treated with silicone oil is used to obtain long-term chargeability maintenance (see, for example, Patent Document 1).

  On the other hand, a method using a crystalline resin as a binder resin has long been known as a means for achieving both low-temperature fixability and prevention of blocking. Further, a technique has been proposed in which a crystalline resin is not used alone as a binder resin, but a crystalline resin and an amorphous resin are used in combination. Specifically, it is a method in which an amorphous polyester resin having a glass transition temperature of 40 ° C. or higher and a crystalline polyester resin having a melting temperature of 130 to 200 ° C. are mixed and used (for example, see Patent Document 2). On the other hand, a technique for obtaining low-temperature fixing by mixing a crystalline resin and an amorphous resin having a low melting temperature and controlling the degree of compatibilization has been proposed (see, for example, Patent Documents 3 and 4).

By the way, in the toner containing the crystalline resin, the external additive is buried, which causes image quality defects in the cleaning process. In particular, in a system using a cleaning process using a cleaning blade, a phenomenon (so-called toner filming) in which toner remaining without being transferred is crushed by the cleaning blade and accumulates on the photosensitive member over time. It has been. As a means for suppressing this phenomenon, there is a method of removing toner filming by externally adding an abrasive such as cerium oxide.
In addition, when the amount of the external additive is increased due to the above-mentioned measures, charge-up may be a problem. As a means for suppressing this, a combination of positively chargeable and negatively chargeable silica has been proposed. (For example, see Patent Documents 5 and 6).
JP 2004-219609 A Japanese Patent Publication No. 63-25335 JP 2004-206081 A Japanese Patent Laid-Open No. 2004-50478 JP 2004-279912 A JP 11-184145 A

An object of the present invention is to provide a negatively charged toner for developing an electrostatic image, an electrostatic image developer, and a toner cartridge capable of preventing the occurrence of image quality defects while maintaining low temperature fixability and capable of forming a stable image over a long period of time. The present invention provides a process cartridge and an image forming apparatus.

The above-mentioned subject is achieved by the following present invention.
That is, the invention according to claim 1 of the present invention is
Toner particles comprising a crystalline resin and a colorant;
Negatively chargeable silica particles having an average primary particle size of 50 nm or more and 150 nm or less treated with silicone oil;
Positively chargeable silica particles having an average primary particle size of 150 nm or more and 250 nm or less;
Abrasive particles,
Containing
The negatively charged toner for developing an electrostatic charge image, wherein the negatively charged silica particles have a free oil amount of 0.1% by mass or more and 3% by mass or less.

The invention according to claim 2, wherein the toner, the toner is the electrostatic image developer is a negatively charged toner according to claim 1.

According to a third aspect of the present invention, there is provided a toner cartridge in which at least toner is contained, and the toner is the negatively charged toner for developing an electrostatic image according to the first aspect.

According to a fourth aspect of the present invention, there is provided a process cartridge comprising at least a developer holder and containing the electrostatic charge image developer according to the second aspect .

According to a fifth aspect of the present invention, there is provided an image carrier, a developing unit that develops the electrostatic image formed on the image carrier as a toner image with a developer, and a toner image formed on the image carrier. An image forming apparatus comprising: a transfer unit that transfers onto a transfer body; and a fixing unit that fixes a toner image transferred onto the transfer body, wherein the developer is the electrostatic charge image developer according to claim 2. Device.

According to the first aspect of the present invention, there is provided an electrostatic image developing toner capable of preventing the occurrence of image quality defects while maintaining low-temperature fixability and capable of forming a stable image over a long period of time. be able to.
According to the first aspect of the present invention, it is possible to obtain a toner for developing an electrostatic charge image that does not cause excessive wear of the photoreceptor.
According to the second aspect of the present invention, it is possible to provide an electrostatic charge image developer capable of preventing the occurrence of image quality defects while maintaining low-temperature fixability and capable of forming a stable image over a long period of time.
According to the third aspect of the present invention, it is possible to prevent the occurrence of image quality defects while maintaining the low temperature fixability, and to facilitate the supply of the electrostatic charge image developing toner capable of forming a stable image over a long period of time. Maintainability of characteristics can be improved.
According to the fourth aspect of the invention, it is possible to prevent the occurrence of image quality defects while maintaining the low temperature fixability, and further facilitate the handling of the electrostatic charge image developing agent capable of forming a stable image over a long period of time. The adaptability to the image forming apparatus having the above configuration can be improved.
According to the fifth aspect of the present invention, image quality defects can be prevented while maintaining low-temperature fixability, and a stable image can be formed over a long period of time.

Hereinafter, the present invention will be described in detail.
<Toner for electrostatic image development>
The negatively charged toner for developing an electrostatic image of the present invention (hereinafter sometimes referred to as “toner”) has toner particles containing a crystalline resin and a colorant, and an average primary particle size treated with silicone oil of 50 nm to 150 nm. And the amount of free oil of the silica particles is 0.1% by mass or more and 3% by mass or less.
However, in the toner of the present invention, silica particles having an average primary particle size of 50 nm or more and 150 nm or less are negatively charged silica particles, and positively charged silica particles having an average primary particle size of 150 nm or more and 250 nm or less, and polishing What contains agent particles is employed.

  As described above, it is effective to use a crystalline resin in order to obtain low temperature fixability without lowering the molecular weight or glass transition temperature of the binder resin. This is due to the sharp melting characteristics of the crystalline resin itself and, when an amorphous resin is used in combination, it is compatible with this and has the effect of apparently lowering the glass transition temperature. On the other hand, as a means for improving the storage property of the toner, there is a method in which the adhesion force between the toners is reduced by externally adding hydrophobic additive particles such as silica and titania to the toner particles. By taking such measures, low-temperature fixing has been realized while obtaining storability even when a crystalline resin is used.

As the external additive, silica treated with silicone oil has been used from the viewpoint of maintaining chargeability for a long period of time even in a high-temperature and high-humidity environment without causing problems such as fogging. When the treated silicone oil is liberated and adheres to the toner, the fluidity of the developer is remarkably lowered, and the developer aggregates in the developing device to cause color streaks.
As will be described later, the present inventors use silica having a specific particle size range and suppress the liberation of the silicone oil treated with the silica as much as possible, so that even if a crystalline resin is used as a toner binder resin, development can be performed. It has been found that the occurrence of color spots, fogging, and color streaks can be suppressed over a long period of time without causing a decrease in fluidity of the agent.

Specifically, silica particles treated with silicone oil having an average primary particle size of 50 nm to 150 nm and having a free oil amount of 0.1% by mass to 3% by mass are used. Was found to be necessary.
When the average primary particle size of the silica particles is less than 50 nm, the silica particles are easily embedded in the toner surface. If it exceeds 150 nm, it will be difficult to adhere to the toner surface or the dispersibility will be reduced. The average primary particle size is desirably 70 nm or more and 140 nm or less, and more desirably 80 nm or more and 130 nm or less.

When the amount of the free oil is less than 0.1% by mass, the chargeability of the toner cannot be maintained particularly in a high temperature and high humidity environment. On the other hand, when it exceeds 3% by mass, the powder agglomeration property of the toner is deteriorated, and the powder transportability / developability / transferability is deteriorated.
The amount of the free oil is preferably 0.1% by mass or more and 2.6% by mass or less, and more preferably 0.3% by mass or more and 2.0% by mass or less.

  As an external additive for the toner, an abrasive is used to remove discharge products, filming toner, and the like on the surface of the photoreceptor. However, in the case of a toner containing a crystalline resin, non-electrostatic adhesion is strong. Therefore, the adhesive force with the cleaning blade becomes strong, and the toner stays between the cleaning blade and the photosensitive member (image holding member) during cleaning. At this time, if the toner with externally added abrasive stays near the nip of the cleaning blade, the abrasive is strongly pressed against the photoconductor, so that the photoconductor is excessively worn and the life of the photoconductor Could be significantly shortened.

As a means for suppressing such excessive wear of the photosensitive member, silica having an average primary particle size of 50 nm or more and 200 nm or less is used as an external additive and is supplied to the cleaning unit at the same time as the polishing agent. In comparison, silica particles having a smaller particle diameter are deposited in a region of the nip portion that is strongly pressed against the photoconductor, so that toner retention and penetration into the nip portion can be suppressed.
However, it has been found that when a crystalline resin is used for the toner, excessive wear of the photoreceptor cannot be suppressed by simply externally adding silica in the particle size range. This is estimated as follows. When a crystalline resin is used for the toner, the crystalline resin portion in the toner becomes soft, and a portion having different hardness is unevenly distributed in one toner. When an external additive is added to the toner having such a structure, the external additive on the surface is uniform immediately after the external addition, but the external additive is unevenly distributed or buried in a soft part due to stress such as stirring. If the external additive is unevenly distributed and buried, the area of the non-externally added portion of the toner increases, and the non-electrostatic adhesion to the cleaning blade increases. Further, the unevenly distributed or buried silica does not separate from the toner even if supplied to the cleaning unit, and does not accumulate at the nip. As a result, even if silica having a particle size in the above range is externally added, a phenomenon occurs in which the photoconductor is excessively worn.

Further, it is possible to increase the external additive surface coverage of the toner by increasing the external additive such as silica and reduce the non-electrostatic adhesion force, but if the amount of the external additive is simply increased, At the same time, the amount of charge is greatly increased, and the image may become low density due to charge-up.
In this case, the above-mentioned method using both positively and negatively chargeable silica is effective. However, although charge-up can be suppressed by electrostatically balancing positive and negative charges, the charge decreases due to embedding. Could happen as well. It has been found that this tendency is particularly confirmed when a crystalline resin is used for the toner.

As a result of studying the above problems, the present inventors have found that as an external additive, a positively chargeable silica having an average primary particle size of 150 nm to 250 nm and a negatively chargeable silica having an average primary particle size of 50 nm to 150 nm. As a result, it was found that a stable image formation can be realized while maintaining low-temperature fixing without excessively abrading the photoreceptor even with a toner using a crystalline resin.
Although the details of the above action are not clear, when a crystalline resin is used, the external additive structure changes as described above, while ensuring the external additive coverage by adding silica particles having different polarities. This is considered to be because it is possible to control the charge amount balance and suppress the charge-up. In addition, by using different-sized silica particles having different polarities, the positively-charged silica particles having a large particle size are compared with the negatively-charged silica particles having a small particle size when subjected to stress. Since the toner is buried in the soft part of the toner first, the uneven distribution and embedding of the negatively-charged silica particles can be suppressed as much as possible. It is considered that a certain amount of silica can be supplied.

  Furthermore, by making the negatively chargeable silica particles contain a small amount of free oil as described above, the fluidity of small-diameter toner having a small particle size and poor toner fluidity is also improved. Since it is easy to replace, and accumulation of a small diameter toner having an abrasive can also be suppressed, in addition to suppressing the generation of color points, fogging, and color streaks, the reduction of the photoreceptor wear is further made more efficient.

When the average primary particle size of the positively chargeable silica particles is within the above range, the negatively chargeable silica can be buried in the crystalline resin portion of the toner prior to the negatively chargeable silica. When the average primary particle diameter of the negatively chargeable silica particles is in the above range, the negatively charged silica particles can be efficiently supplied to the nip portion during cleaning without being preferentially buried in the crystalline resin portion of the toner.
The average primary particle size of the positively chargeable silica particles is more preferably 150 nm or more and 200 nm or less, and further preferably 170 nm or more and 200 nm or less. The average primary particle size of the negatively chargeable silica particles is more preferably 50 nm or more and 150 nm or less, and further preferably 70 nm or more and 130 nm or less.

Hereinafter, a specific configuration of the toner will be described with reference to embodiments.
(Toner particles)
-Crystalline resin-
The toner particles of this embodiment contain a crystalline resin.
The crystalline resin is desirably used in the range of 5% by mass or more and 30% by mass or less of the binder resin constituting the toner. More preferably, it is the range of 8 mass% or more and 20 mass% or less. When the proportion of the crystalline resin exceeds 30% by mass, good fixing characteristics can be obtained, but the phase separation structure in the fixed image becomes non-uniform, and the strength of the fixed image, particularly the scratch strength, decreases, and is easily scratched. May present problems. On the other hand, if it is less than 5% by mass, sharp melting characteristics derived from the crystalline resin cannot be obtained, and the amorphous resin is simply plasticized, while ensuring good low-temperature fixability, and toner blocking resistance, Image preservation may not be maintained.

  The “crystalline resin” refers to a resin having a clear endothermic peak, not a stepwise change in endothermic amount in differential scanning calorimetry (DSC). Further, the endothermic peak may show a peak having a width of 40 to 50 ° C. when the toner is used. In the case of a polymer obtained by copolymerizing another component with the main chain of the crystalline resin, if the other component is 50% by mass or less, this copolymer is also called a crystalline resin.

The crystalline resin is not particularly limited as long as it is a crystalline resin, and specific examples thereof include crystalline polyester resins and crystalline vinyl resins. From the viewpoints of properties and adjustment of the melting temperature within a preferable range, a crystalline polyester is preferable. Furthermore, an aliphatic crystalline polyester resin having an appropriate melting temperature is more preferable.
All the polyester resins including the crystalline polyester resin used in the toner of the present embodiment and other amorphous polyester resins described later are synthesized from a polyvalent carboxylic acid component and a polyhydric alcohol component. In addition, in this embodiment, a commercial item may be used as said polyester resin, and what was synthesize | combined suitably may be used.

  Examples of the polyvalent carboxylic acid component include oxalic acid, succinic acid, glutaric acid, adipic acid, peric acid, azelaic acid, sebacic acid, 1,9-nonanedicarboxylic acid, 1,10-decanedicarboxylic acid, 1, Aliphatic dicarboxylic acids such as 12-dodecanedicarboxylic acid, 1,14-tetradecanedicarboxylic acid, 1,18-octadecanedicarboxylic acid; phthalic acid, isophthalic acid, terephthalic acid, naphthalene-2,6-dicarboxylic acid, malonic acid, mesaconine Aromatic dicarboxylic acids such as dibasic acids such as acids; and the like, and anhydrides and lower alkyl esters thereof are also included, but not limited thereto.

  Examples of the trivalent or higher carboxylic acid include 1,2,4-benzenetricarboxylic acid, 1,2,5-benzenetricarboxylic acid, 1,2,4-naphthalenetricarboxylic acid, and the like, and anhydrides thereof. And lower alkyl esters. These may be used individually by 1 type and may use 2 or more types together.

  Moreover, as an acid component, it is preferable that the dicarboxylic acid component which has a sulfonic acid group other than the above-mentioned aliphatic dicarboxylic acid and aromatic dicarboxylic acid is contained. The dicarboxylic acid having a sulfonic acid group is effective in that it can favorably disperse a colorant such as a pigment. In addition, when particles are prepared by emulsifying or suspending the entire resin in water, if there are sulfonic acid groups, emulsification or suspension can be performed without using a surfactant as described later.

  Examples of the dicarboxylic acid having a sulfone group include, but are not limited to, 2-sulfoterephthalic acid sodium salt, 5-sulfoisophthalic acid sodium salt, and sulfosuccinic acid sodium salt. Moreover, these lower alkyl esters, acid anhydrides, etc. are also mentioned. The divalent or higher carboxylic acid component having a sulfonic acid group is contained in an amount of 0 to 20 mol%, preferably 0.5 to 10 mol%, based on all carboxylic acid components constituting the polyester. Is desirable. If the content is low, the stability of the emulsified particles with time deteriorates. On the other hand, if the content exceeds 20 mol%, not only the crystallinity of the polyester resin is lowered, but also the process of fusing the particles after agglomeration is adversely affected. There may be a problem that it becomes difficult to adjust.

  Furthermore, it is more preferable to contain a dicarboxylic acid component having a double bond in addition to the aforementioned aliphatic dicarboxylic acid and aromatic dicarboxylic acid. A dicarboxylic acid having a double bond can be suitably used to prevent hot offset at the time of fixing in that it can be radically cross-linked through the double bond. Examples of such dicarboxylic acids include, but are not limited to, maleic acid, fumaric acid, 3-hexenedioic acid, and 3-octenedioic acid. In addition, these lower esters, acid anhydrides and the like are also included. Among these, fumaric acid, maleic acid and the like are mentioned in terms of cost.

  The polyhydric alcohol component is preferably an aliphatic diol, and more preferably a linear aliphatic diol having a main chain portion having 7 to 20 carbon atoms. When the aliphatic diol is branched, the crystallinity of the polyester resin is lowered and the melting temperature is lowered, so that toner blocking resistance, image storage stability, and low-temperature fixability may be deteriorated. When the number of carbon atoms is less than 7, when the polycondensation with an aromatic dicarboxylic acid is performed, the melting temperature becomes high and fixing at low temperature may be difficult. On the other hand, when it exceeds 20, it is difficult to obtain a practical material. It is easy to become. The carbon number is more preferably 14 or less.

  Specific examples of the aliphatic diol preferably used for the synthesis of the crystalline polyester resin of the present embodiment include ethylene glycol, 1,3-propanediol, 1,4-butanediol, and 1,5-pentane. Diol, 1,6-hexanediol, 1,7-heptanediol, 1,8-octanediol, 1,9-nonanediol, 1,10-decanediol, 1,11-undecanediol, 1,12-dodecanediol 1,13-tridecanediol, 1,14-tetradecanediol, 1,18-octadecanediol, 1,14-eicosandecanediol, and the like, but are not limited thereto. Among these, considering availability, 1,8-octanediol, 1,9-nonanediol, and 1,10-decanediol are preferable.

  Examples of the trivalent or higher alcohol include glycerin, trimethylolethane, trimethylolpropane, pentaerythritol and the like. These may be used individually by 1 type and may use 2 or more types together.

Among the polyhydric alcohol components, the content of the aliphatic diol component is preferably 80 mol% or more, and more preferably 90 mol% or more. When the content of the aliphatic diol component is less than 80 mol%, the crystallinity of the polyester resin is lowered and the melting temperature is lowered, so that toner blocking resistance, image storage stability, and low-temperature fixability may be deteriorated. is there.
If necessary, monovalent acids such as acetic acid and benzoic acid and monovalent alcohols such as cyclohexanol benzyl alcohol can also be used for the purpose of adjusting the acid value and hydroxyl value.

  In addition to the polymer whose constituent component is a 100% polyester structure, the crystalline polyester resin as described above is also a polymer (copolymer) obtained by polymerizing a component constituting polyester and other components together. means. However, in the latter case, the component other than the polyester constituting the polymer (copolymer) is 50% by mass or less.

The method for producing the crystalline polyester resin is not particularly limited, and can be produced by a general polyester polymerization method in which an acid component and an alcohol component are reacted. Examples thereof include direct polycondensation and transesterification. They are manufactured using different types of monomers.
The production of the crystalline polyester resin can be carried out at a polymerization temperature of 180 ° C. or higher and 230 ° C. or lower, and the reaction system is reduced in pressure as necessary, and the reaction is carried out while removing water and alcohol generated during the condensation. When the monomer is not dissolved or compatible at the reaction temperature, a solvent having a high boiling point may be added as a solubilizer and dissolved. In the polycondensation reaction, the dissolution auxiliary solvent is distilled off. In the case where a monomer having poor compatibility exists in the copolymerization reaction, it is preferable that the monomer having poor compatibility and the monomer and the acid or alcohol to be polycondensed are condensed in advance and then polycondensed together with the main component.

  On the other hand, the crystalline vinyl resin includes amyl (meth) acrylate, hexyl (meth) acrylate, heptyl (meth) acrylate, octyl (meth) acrylate, nonyl (meth) acrylate, (meth) acrylic. Decyl acid, undecyl (meth) acrylate, tridecyl (meth) acrylate, myristyl (meth) acrylate, cetyl (meth) acrylate, stearyl (meth) acrylate, oleyl (meth) acrylate, (meth) acrylic acid Examples thereof include vinyl resins using long-chain alkyl such as behenyl and alkenyl (meth) acrylic acid esters. In the present specification, the description “(meth) acryl” means to include both “acryl” and “methacryl”.

  The melting temperature of the crystalline resin is preferably 50 ° C. or higher and 100 ° C. or lower, more preferably 60 ° C. or higher and 80 ° C. or lower. When the melting temperature is lower than 50 ° C., the storage stability of the toner and the storage stability of the toner image after fixing may become a problem. On the other hand, when the temperature is higher than 100 ° C., sufficient low-temperature fixing may not be obtained as compared with conventional toners. The crystalline resin may show a plurality of melting peaks, but in this embodiment, the maximum peak is regarded as the melting temperature.

  The melting temperature of the toner containing the crystalline resin is preferably 50 ° C. or higher and 90 ° C. or lower, and more preferably 60 ° C. or higher and 80 ° C. or lower. Since the toner sharply decreases in viscosity at the melting temperature, blocking occurs when the toner is stored in a temperature environment higher than the melting temperature. Therefore, the melting temperature of the toner is preferably not less than the lower limit temperature in a general high-temperature environment exposed after storing the toner or after forming the image, that is, not less than 50 ° C. On the other hand, if the melting temperature exceeds 90 ° C., low-temperature fixing may not be possible.

The toner of the exemplary embodiment only needs to contain the crystalline resin, and may contain an amorphous resin in addition to the above.
A known resin material can be used as the amorphous resin, but an amorphous polyester resin is particularly preferable. The amorphous polyester resin used in the present embodiment is obtained mainly by polycondensation of polyvalent carboxylic acids and polyhydric alcohols. When an amorphous polyester resin is used, it is advantageous in that a resin particle dispersion can be easily prepared by adjusting the acid value of the resin or by emulsifying and dispersing using an ionic surfactant. .

  Examples of the polyvalent carboxylic acid include terephthalic acid, isophthalic acid, phthalic anhydride, trimellitic anhydride, pyromellitic acid, naphthalenedicarboxylic acid, and the like; maleic anhydride, fumaric acid, succinic acid, And aliphatic carboxylic acids such as alkenyl succinic anhydride and adipic acid; alicyclic carboxylic acids such as cyclohexanedicarboxylic acid; and the like. These polyvalent carboxylic acids can be used alone or in combination. Of these polycarboxylic acids, aromatic carboxylic acids are preferably used, and in order to have a crosslinked structure or a branched structure for the purpose of ensuring good fixability, a trivalent or higher carboxylic acid (trivalent or trivalent) is used together with a dicarboxylic acid. It is preferable to use merit acid or its acid anhydride in combination.

  Examples of the polyhydric alcohol include aliphatic diols such as ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, butanediol, hexanediol, neopentylglycol, and glycerin; cyclohexanediol, cyclohexanedimethanol, hydrogenated bisphenol And alicyclic diols such as A; aromatic diols such as an ethylene oxide adduct of bisphenol A and a propylene oxide adduct of bisphenol A; One or more of these polyhydric alcohols can be used, but aromatic diols and alicyclic diols are preferred, and among these, aromatic diols are more preferred. In order to secure good fixing properties, a trihydric or higher polyhydric alcohol (glycerin, trimethylolpropane, pentaerythritol) may be used in combination with the diol in order to take a crosslinked structure or a branched structure.

  In addition, at least one of monocarboxylic acid and monoalcohol is further added to the polyester resin obtained by polycondensation of polycarboxylic acid and polyhydric alcohol, and at least one of hydroxyl group and carboxyl group at the polymerization terminal is added. The acid value of the polyester resin may be adjusted by esterification. Examples of the monocarboxylic acid include acetic acid, acetic anhydride, benzoic acid, trichloroacetic acid, trifluoroacetic acid, propionic anhydride, etc., and examples of the monoalcohol include methanol, ethanol, propanol, octanol, 2-ethylhexanol, trifluoroethanol, Examples include trichloroethanol, hexafluoroisopropanol, and phenol.

The amorphous polyester resin can be produced by subjecting the polyhydric alcohol and polyvalent carboxylic acid to a condensation reaction according to a conventional method. For example, the above polyhydric alcohol and polyvalent carboxylic acid, if necessary, a catalyst, and blended in a reaction vessel equipped with a thermometer, a stirrer, a flow-down condenser, and in the presence of an inert gas (such as nitrogen gas), Heating at 150 ° C. or more and 250 ° C. or less to continuously remove by-product low-molecular compounds out of the reaction system, stop the reaction when a predetermined acid value is reached, cool the target reactant It can be manufactured by acquiring.
Moreover, as a catalyst used for this synthesis | combination, esterification catalysts, such as organic metals, such as dibutyltin dilaurate and dibutyltin oxide, and metal alkoxides, such as tetrabutyl titanate, are mentioned, for example. The amount of such a catalyst added is preferably 0.01% by mass or more and 1.00% by mass or less based on the total amount of raw materials.

  The amorphous resin used in the present embodiment preferably has a weight average molecular weight Mw of 5,000 or more and 1,000,000 or less by molecular weight measurement by a gel permeation chromatography (GPC) method soluble in tetrahydrofuran (THF). More preferably, the molecular weight Mn is preferably 7,000 or more and 10,000 or less, and the molecular weight distribution Mw / Mn is preferably 1.5 or more and 100 or less, more preferably 2 or more and 60 or less. It is as follows.

  If the weight average molecular weight and number average molecular weight are smaller than the above ranges, it is effective for low-temperature fixability, but not only the hot offset resistance is remarkably deteriorated but also the glass transition temperature of the toner is lowered. It may also adversely affect storage stability such as blocking. On the other hand, if the molecular weight is larger than the above range, the hot offset resistance can be sufficiently provided, but the low-temperature fixability is deteriorated, and since the bleeding of the crystalline polyester phase present in the toner is inhibited, the document storage stability is adversely affected. May affect. Therefore, it becomes easy to satisfy both the low-temperature fixability, the hot offset resistance, and the document storage stability by satisfying the above conditions.

  Further, the acid value (the number of mg of KOH necessary for neutralizing 1 g of resin) of the polyester resin (same as the crystalline polyester resin) is easy to obtain the molecular weight distribution as described above, and the toner particles by the emulsion dispersion method. 1 mgKOH / g or more and 30 mgKOH / g because it is easy to ensure the granulation property of the toner and it is easy to maintain the environmental stability of the obtained toner (stability of chargeability when the temperature and humidity change). g or less is preferable. The acid value of the polyester resin can be adjusted by controlling the carboxyl group at the terminal of the polyester according to the blending ratio of the raw polyhydric carboxylic acid and polyhydric alcohol and the reaction rate. Or what has a carboxyl group in the principal chain of polyester is obtained by using trimellitic anhydride as a polyvalent carboxylic acid component.

  A styrene acrylic resin can also be used as a known amorphous resin. Examples of monomers that can be used in this case include styrenes such as styrene, parachlorostyrene, and α-methylstyrene; methyl acrylate, ethyl acrylate, n-propyl acrylate, n-butyl acrylate, and lauryl acrylate. Esters having vinyl groups such as 2-ethylhexyl acrylate, methyl methacrylate, ethyl methacrylate, n-propyl methacrylate, lauryl methacrylate, 2-ethylhexyl methacrylate; vinyl nitriles such as acrylonitrile and methacrylonitrile; Vinyl ethers such as vinyl methyl ether and vinyl isobutyl ether; vinyl ketones such as vinyl methyl ketone, vinyl ethyl ketone and vinyl isopropenyl ketone; polyolefins such as ethylene, propylene and butadiene; And a copolymer obtained by combining two or more of these, or a mixture thereof. Furthermore, epoxy resins, polyester resins, polyurethane resins, polyamide resins, cellulose resins, polyether resins, etc. A vinyl condensation resin, a mixture of these with the vinyl resin, or a graft polymer obtained when a vinyl monomer is polymerized in the presence of these can also be used.

  The glass transition temperature of the amorphous resin used in the present embodiment is preferably 35 ° C. or more and 100 ° C. or less, and is 50 ° C. or more and 80 ° C. or less from the viewpoint of the balance between storage stability and toner fixing property. More preferably. When the glass transition temperature is less than 35 ° C., the toner tends to be blocked during the storage or in the developing machine (a phenomenon in which toner particles are aggregated into a lump). On the other hand, if the glass transition temperature exceeds 100 ° C., the fixing temperature of the toner becomes high, which is not preferable.

The softening point of the amorphous resin is preferably in the range of 80 ° C. or higher and 130 ° C. or lower. More preferably, it is the range of 90 degreeC or more and 120 degrees C or less. When the softening point is 80 ° C. or less, the toner and the image stability of the toner after fixing and during storage may be significantly deteriorated. On the other hand, if the softening point exceeds 130 ° C., the low-temperature fixability may deteriorate.
The softening point was measured by using a flow tester (manufactured by Shimadzu Corporation, CFT-500C), preheating: 80 ° C./300 seconds, plunger pressure: 0.980665 MPa, die size: diameter 1 mm × length 1 mm, heating rate: 3 It was determined as an intermediate temperature between the melting start temperature and the melting end temperature under the condition of 0.0 ° C./min.

  The preparation of the resin particle dispersion using the resin described above can be prepared by, for example, adjusting the acid value of the resin or emulsifying and dispersing using an ionic surfactant or the like.

-Colorant-
The colorant used in the present embodiment is not particularly limited as long as it is a known colorant, and examples of the black pigment include carbon black and magnetic powder. Examples of yellow pigments include Hansa Yellow, Hansa Yellow 10G, Benzidine Yellow G, Benzidine Yellow GR, Slen Yellow, Quinoline Yellow, and Permanent Yellow NCG. Red pigments include Bengala, Watch Young Red, Permanent Red 4R, Resol Red, Brilliantamine 3B, Brilliantamine 6B, DuPont Oil Red, Pyrazolone Red, Rhodamine B Lake, Lake Red C, Rose Bengal, Eoxin Red, Alizarin Lake Etc. Blue pigments include bitumen, cobalt blue, alkali blue rake, Victoria blue rake, fast sky blue, induslen blue BC, aniline blue, ultramarine blue, calco oil blue, methylene blue chloride, phthalocyanine blue, phthalocyanine green, malachite green oxare. Rate and so on. Furthermore, these can be mixed and used in the state of a solid solution.

These colorants are dispersed by a known method, and for example, a rotary shear type homogenizer, a media type dispersing machine such as a ball mill, a sand mill, or an attritor, a high-pressure opposed collision type dispersing machine, or the like is preferably used. These colorants can be dispersed in an aqueous solvent using a polar ionic surfactant and a homogenizer as described above to prepare a colorant particle dispersion.
The content of the colorant in the toner is preferably in the range of 1 part by weight to 30 parts by weight with respect to 100 parts by weight of the binder resin, and a colorant that has been surface-treated as necessary is used. It is also effective to use a pigment dispersant. By appropriately selecting the type of the colorant, yellow toner, magenta toner, cyan toner, black toner and the like can be obtained.

-Other ingredients-
A release agent can be used in the toner of the exemplary embodiment as necessary. As the release agent, a substance having a main maximum peak measured in accordance with ASTM D3418-8 in the range of 50 ° C. or higher and 140 ° C. or lower is preferable. If the main maximum peak is less than 50 ° C., offset may easily occur during fixing. On the other hand, if the temperature exceeds 140 ° C., the fixing temperature becomes high, and the glossiness may be impaired due to insufficient smoothness of the image surface.
For the measurement of the main maximum peak, for example, DSC-7 manufactured by Perkin Elmer can be used. The temperature correction of the detection part of this apparatus uses the melting temperature of indium and zinc, and the correction of heat uses the heat of fusion of indium. As the sample, an aluminum pan is used, an empty pan is set as a control, and the measurement is performed at a heating rate of 10 ° C./min.

The viscosity η1 at 160 ° C. of the release agent is preferably in the range of 20 cps to 600 cps. If the viscosity η1 is less than 20 cps, hot offset is likely to occur, and if it is greater than 600 cps, cold offset may occur during fixing.
Further, the ratio (η2 / η1) of the viscosity η1 at 160 ° C. and the viscosity η2 at 200 ° C. of the release agent is preferably in the range of 0.5 to 0.7. If η2 / η1 is smaller than 0.5, the bleed amount at a low temperature is small and a cold offset may occur. On the other hand, if the ratio is larger than 0.7, the amount of bleeding at the time of fixing at a high temperature increases, which may cause a wax offset and may cause a problem in peeling stability.

Specific examples of the release agent include low molecular weight polyolefins such as polyethylene, polypropylene and polybutene; silicones having a softening point by heating; oleic acid amide, erucic acid amide, ricinoleic acid amide, stearic acid amide, etc. Fatty acid amides; plant waxes such as carnauba wax, rice wax, candelilla wax, tree wax, jojoba oil, etc .; animal waxes such as beeswax; montan wax, ozokerite, ceresin, paraffin wax, microcrystalline wax, Minerals such as Fischer-Tropsch wax, petroleum-based waxes, and modified products thereof can be used.
These release agents are dispersed in water together with ionic surfactants and polymer electrolytes such as polymer acids and polymer bases, and are homogenizers and pressure discharge type dispersers that can be heated to the melting temperature or higher and subjected to strong shearing. Thus, a release agent dispersion containing release agent particles having a particle diameter of 1 μm or less can be prepared.

In addition, a lubricant or a charge control agent can be used for the toner of the exemplary embodiment as necessary.
Examples of the lubricant that can be used include fatty acid amides such as ethylene bisstearylamide and oleic acid amide, and fatty acid metal salts such as zinc stearate and calcium stearate. The charge control agent is added to improve and stabilize the chargeability. For example, a dye composed of a complex such as a quaternary ammonium salt compound, a nigrosine compound, aluminum, iron, or chromium, or triphenylmethane. Various commonly used charge control agents such as pigments can be used.

(Manufacture of toner particles)
In the present exemplary embodiment, the toner is a toner in an acidic or alkaline aqueous medium such as an aggregation / unification method, a suspension polymerization method, a dissolution suspension granulation method, a dissolution suspension method, or a dissolution emulsion aggregation aggregation method. It is preferable to produce the particles by a wet production method, and an aggregation coalescence method is particularly preferred.
More specifically, the toner of this embodiment, a resin fine particle dispersion in which at least a particle diameter of 1 μm or less is dispersed in a first resin fine particle, a colorant particle dispersion in which a colorant particle is dispersed, and, if necessary, A first aggregating step of mixing a release agent particle dispersion in which release agent particles are dispersed to form core agglomerated particles including the first resin particles, the colorant particles, and the release agent particles; Forming a shell layer containing second resin particles on the surface of the core aggregated particles to obtain core / shell aggregated particles; and the core / shell aggregated particles as the first resin particles or the first It is desirable that the resin particles are produced by a production method including at least a fusion / union step in which the resin particles are heated to a temperature equal to or higher than the glass transition temperature.

In the first aggregation step, first, a resin particle dispersion, a colorant particle dispersion, and a release agent particle dispersion as necessary are prepared. The resin particle dispersion is prepared by dispersing the first resin particles prepared by emulsion polymerization or the like in a solvent using an ionic surfactant. The colorant particle dispersion is obtained by using the ionic surfactant opposite to the ionic surfactant used in the preparation of the resin particle dispersion to obtain the colorant particles of a desired color such as black, blue, red, yellow, etc. Prepare by dispersing in solvent. In addition, the release agent particle dispersion is prepared by dispersing the release agent in water together with a polymer electrolyte such as an ionic surfactant, a polymer acid, or a polymer base, and heating it above the melting temperature and applying strong shear. It is prepared by granulating with a homogenizer or pressure discharge type disperser.
Next, the resin fine particle dispersion, the colorant particle dispersion, and the release agent particle dispersion are mixed, and the first resin fine particles, the colorant particles, and the release agent particles are hetero-aggregated to obtain a desired toner diameter. Aggregated particles (core agglomerated particles) having first diameters and containing first resin fine particles, colorant particles, and release agent particles are formed.

In the second aggregating step, the second resin particles are adhered to the surface of the core agglomerated particles obtained in the first aggregating step by using a resin particle dispersion containing the second resin particles, and the desired thickness is obtained. By forming the coating layer (shell layer), aggregated particles (core / shell aggregated particles) having a core / shell structure in which a shell layer is formed on the surface of the core aggregated particles are obtained. In addition, the 2nd resin particle used in this case may be the same as the 1st resin particle, and may differ.
The particle diameters of the first resin particles, the second resin particles, the colorant particles, and the release agent particles used in the first and second aggregating steps are adjusted to a desired value for the toner diameter and the particle size distribution. In order to facilitate this, it is preferably 1 μm or less, and more preferably in the range of 100 nm to 300 nm.

In the first aggregation step, the balance of the amounts of the two polar ionic surfactants (dispersants) contained in the resin particle dispersion or the colorant particle dispersion can be shifted in advance. For example, an inorganic metal salt such as calcium nitrate or a polymer of an inorganic metal salt such as barium sulfate is ionically neutralized and heated below the glass transition temperature of the first resin particles to form core agglomerated particles. Can be produced.
In such a case, in the second agglomeration step, the resin fine particle dispersion treated with the dispersant having the polarity and the amount so as to compensate for the deviation in the balance between the two polar dispersants as described above is used for the core agglomeration. A core / shell aggregated particle is prepared by adding to a solution containing the particles and further heating slightly below the glass transition temperature of the core aggregated particle or the second resin fine particle used in the second aggregation step as necessary. be able to. In addition, the 1st and 2nd aggregation process may be repeatedly performed in multiple steps stepwise.

Next, in the fusion / union process, the core / shell aggregated particles obtained through the second aggregation process are used as a first or second resin particle contained in the core / shell aggregated particles in a solution. The toner particles are obtained by heating above the glass transition temperature (if the resin type is two or more, the glass transition temperature of the resin having the highest glass point transition temperature), and fusing and coalescing.
After completion of the coalescence / unification process, toner particles formed in the solution are dried through a known washing process, solid-liquid separation process, and drying process to obtain toner particles. In addition, it is preferable that the washing | cleaning process performs substitution washing | cleaning by ion-exchange water fully from a charging point. The solid-liquid separation step is not particularly limited, but suction filtration, pressure filtration, and the like are preferably used from the viewpoint of productivity. Further, although the drying process is not particularly limited, freeze drying, flash jet drying, fluidized drying, vibration fluidized drying and the like are preferably used from the viewpoint of productivity.

(External additive)
In the toner of the exemplary embodiment, silica particles having a volume average primary particle size treated with silicone oil of 50 nm to 150 nm and a free oil amount of 0.1% to 3% by mass are used as an external additive.
As the silicone oil for surface-treating the silica particles, a known silicone oil can be used, and a dry method such as a spray drying method in which a treatment agent or a solution containing a treatment agent is sprayed on particles suspended in a gas phase. The particles can be treated by a wet method in which particles are immersed in a solution containing a method or a treating agent and dried.

  Silicone oils include dimethyl silicone oil, alkyl-modified silicone oil, amino-modified silicone oil, carboxyl-modified silicone oil, epoxy-modified silicone oil, fluorine-modified silicone oil, alcohol-modified silicone oil, polyether-modified silicone oil, methylphenyl silicone oil, Methyl hydrogen silicone oil, mercapto modified silicone oil, higher fatty acid modified silicone oil, phenol modified silicone oil, methacrylic acid modified silicone oil, polyether modified silicone oil, methyl styryl modified silicone oil and the like can be used.

  In this embodiment, the amount of free oil in the silica particles is considerably reduced. This is because, in the treatment of the silicone oil, the particles in a solution containing a treatment method or a dry method such as a spray drying method in which a treatment agent or a solution containing the treatment agent is sprayed on particles suspended in a gas phase. This can be achieved by removing the excessively treated silicone oil by dipping in a solvent such as ethanol again after treatment by a wet method such as dipping and drying.

The silica particles used in the present embodiment are preferably monodispersed spherical silica particles. The reason for this is that general fumed silica has a true specific gravity of 2.2, and the maximum particle size of 50 nm is the limit from the viewpoint of production. Moreover, although the particle size can be increased as an aggregate, uniform dispersion and a stable spacer effect cannot be obtained. Since monodispersed spherical silica is monodispersed and spherical, it can be uniformly dispersed on the surface of the toner particles, and a stable spacer effect can be obtained.
The definition of the monodispersion can be discussed in terms of the standard deviation with respect to the average particle diameter including aggregates, and the standard deviation is preferably number average particle diameter × 0.22 or less. In addition, the definition of the sphere in the present invention can be discussed in terms of Wadell's sphericity, and the sphericity is preferably 0.6 or more, and more preferably 0.8 or more.

The monodispersed spherical silica particles can be obtained by a sol-gel method that is a wet method. The particle size of the monodispersed spherical silica particles can be freely controlled by the hydrolysis of the sol-gel method, the weight ratio of alkoxysilane, ammonia, alcohol, water in the condensation polymerization step, the reaction temperature, the stirring rate, and the supply rate. Monodisperse and spherical shapes can also be achieved by making this method.
Specifically, tetramethoxysilane is dropped and stirred while applying temperature using ammonia water as a catalyst in the presence of water and alcohol. Next, the silica sol suspension obtained by the reaction is centrifuged to separate it into wet silica gel, alcohol and aqueous ammonia. A solvent is added to wet silica gel to form a silica sol again, and a hydrophobizing agent is added to hydrophobize the silica surface. A general silane compound can be used as the hydrophobizing agent. Next, the target monodispersed spherical silica can be obtained by removing the solvent from the hydrophobized silica sol, drying, and sieve. In addition, the silica thus obtained may be treated again. In addition, the manufacturing method of monodispersed spherical silica is not limited to the said manufacturing method.

As described above, in this embodiment, the silica particles with reduced free oil amount are negatively charged silica particles, and positively charged silica particles having an average primary particle size of 150 nm or more and 250 nm or less, abrasive particles, It is desirable to use together.
Here, regarding the above-mentioned “positive chargeability” and “negative chargeability”, in the present embodiment, silica particles and iron powder are mixed, and the charge amount is determined by the blow-off method in the same manner as the usual toner charge amount measurement method. The measured value was positively charged silica and the negative value was negatively charged silica.

Specifically, the coverage with respect to the iron powder is calculated from the particle size and specific gravity of the silica particles to be measured, and the amount of the external additive charged so that the silica particle coverage with respect to the iron powder is 200% is obtained from the following formula (1). It was.
200 (%) = (√3 / 2π) × (Dc · ρc) / (Da · ρa) × (silica charge amount) / (iron powder charge amount) × 100 Formula (1)
(In the above formula, Dc represents the iron powder particle size (μm), ρc represents the iron powder specific gravity, Da represents the external additive particle size (μm), and ρa represents the external additive specific gravity.)

  Next, 10 g of iron powder and the charged amount of silica obtained by the above calculation were mixed and mixed for 20 minutes with a tumbler mixer. Thereafter, the charge amount was measured by a blow-off method using a charge amount measuring device TB-200 (manufactured by Toshiba Corporation).

The positively chargeable silica and the negatively chargeable silica in the present embodiment have their respective charge polarities by being surface treated with different hydrophobizing agents.
Although there is no restriction | limiting in particular as a hydrophobization processing agent, For example, a silane coupling agent, a titanate coupling agent, an aluminum coupling agent, etc. are mentioned. These may be used individually by 1 type and may use 2 or more types together. Of these, silane coupling agents are preferred.

  As the silane coupling agent, for example, any one of chlorosilane, alkoxysilane, silazane, and a special silylating agent can be used. Here, the following can be illustrated as a hydrophobic treatment agent used for surface treatment.

  That is, methyltrichlorosilane, dimethyldichlorosilane, trimethylchlorosilane, phenyltrichlorosilane, diphenyldichlorosilane, tetramethoxysilane, methyltrimethoxysilane, dimethyldimethoxysilane, phenyltrimethoxysilane, diphenyldimethoxysilane, tetraethoxysilane, methyltriethoxy Silane, dimethyldiethoxysilane, phenyltriethoxysilane, diphenyldiethoxysilane, isobutyltrimethoxysilane, decyltrimethoxysilane, hexamethyldisilazane, N, O- (bistrimethylsilyl) acetamide, N, N-bis (trimethylsilyl) Urea, tert-butyldimethylchlorosilane, vinyltrichlorosilane, vinyltrimethoxysilane, vinyltriethoxy Lan, γ-methacryloxypropyltrimethoxysilane, β- (3,4-epoxycyclohexyl) ethyltrimethoxysilane, γ-glycidoxypropyltrimethoxysilane, γ-glycidoxypropylmethyldiethoxysilane, γ-mercapto Propyltrimethoxysilane, γ-chloropropyltrimethoxysilane, N-2- (aminoethyl) -3-aminopropylmethyldimethoxysilane, N-2- (aminoethyl) -3-aminopropyltrimethoxysilane, N-2 -(Aminoethyl) -3-aminopropyltriethoxysilane, 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, 3-triethoxysilyl-N- (1,3-dimethyl-butylidene) propylamine, N -Phenyl-3-aminopropyl It can be exemplified triethoxysilane, amino-modified alkoxysilane as typical.

In order to obtain the positively charged silica particles, N-2- (aminoethyl) -3-aminopropylmethyldimethoxysilane, N-2- (aminoethyl) -3 is used as a hydrophobizing agent selected from the above. -Aminopropyltrimethoxysilane, N-2- (aminoethyl) -3-aminopropyltriethoxysilane, 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, 3-triethoxysilyl-N- (1, It is preferable to use 3-dimethyl-butylidene) propylamine, N-phenyl-3-aminopropyltriethoxysilane, amino-modified alkoxysilane and the like. In order to obtain negatively charged silica particles, dimethyl silicone oil, alkyl modified silicone oil, amino modified silicone oil, carboxyl modified silicone oil, epoxy modified silicone oil, fluorine modified silicone oil, alcohol modified silicone oil, polyether modified Use silicone oil, methylphenyl silicone oil, methyl hydrogen silicone oil, mercapto modified silicone oil, higher fatty acid modified silicone oil, phenol modified silicone oil, methacrylic acid modified silicone oil, polyether modified silicone oil, methylstyryl modified silicone oil, etc. It is preferable.
In particular, a combination using amino-modified alkoxysilane for positive chargeability and a dimethyl silicone oil for negative chargeability is most preferable.

The treatment amount of the hydrophobizing agent is preferably in the range of 1 to 20 parts by mass with respect to 100 parts by mass of the silica particle core. The treatment amount may not be the same for the positively chargeable silica and the negatively chargeable silica external additive particles, but preferably the treatment amount to the positively chargeable silica particles is in the range of 3 parts by mass or more and 10 parts by mass or less, More preferably, the amount of treatment of the negatively chargeable silica particles is in the range of 3 to 15 parts by mass.
The amount of treatment refers to the amount of the hydrophobizing agent used for the external additive core during the hydrophobizing treatment, not the amount of the hydrophobizing agent actually treated on the external additive particles.

In the present embodiment, in addition to the negatively chargeable silica particles and the positively chargeable silica particles, conventionally known external additives may be used in combination as necessary.
The inorganic oxide particles made of, for example, a _{core, SiO 2, TiO 2, Al} 2 O 3, CuO, ZnO, SnO 2, CeO 2, Fe 2 O 3, MgO, BaO, CaO, K 2 O, Na 2 O , it can be exemplified _{ZrO 2, CaO · SiO 2,} K 2 O · (TiO 2) n, Al 2 O 3 · 2SiO 2, CaCO 3, MgCO 3, BaSO 4, MgSO 4 , and the like. Of these, silica particles and titania fine particles are particularly preferable. It is desirable that the surface of the inorganic oxide fine particles is previously hydrophobized. This hydrophobization treatment is more effective for improving the powder fluidity of the toner, as well as the environmental dependency of charging and the resistance to carrier contamination. The hydrophobic treatment can be performed in the same manner as in the case of the silica particles.

In the toner of the exemplary embodiment, the total surface coverage by the respective external additive particles is preferably 50% or more and 150% or less, and more preferably 60% or more and 120% or less. When the total surface coverage is 50% or more and 150% or less, a stable amount of external additive can be supplied to the cleaning blade nip portion, so that the amount of toner entering the cleaning nip portion is extremely reduced. Generation of color streaks and photoconductor wear can be suppressed.
Here, the surface coverage of the toner by the external additive is obtained by image analysis of a photograph of the toner.
In this case, the surface coverage of the negatively charged silica particles and the positively charged silica particles in the toner (negatively charged silica particles: positively charged silica particles) is determined by the dispersion of the toner surface by each external additive and the coating state. In this respect, it is preferably within the range of 9: 1 to 6: 4, and more preferably within the range of 8: 2 to 7: 3.

In the toner of the present exemplary embodiment, when positively charged silica particles and negatively charged silica particles are used as described above, it is desirable to use abrasive particles together.
As the abrasive particles to be used, known abrasives can be used, but it is particularly preferable to use inorganic particles excellent in abrasiveness. Examples of such inorganic particles include cerium oxide, alumina, silica, titania, zirconia, barium titanate, aluminum titanate, strontium titanate, magnesium titanate, zinc oxide, chromium oxide, antimony oxide, tungsten oxide, tin oxide, Examples include tellurium oxide, manganese oxide, boron oxide, silicon carbide, boron carbide, titanium carbide, silicon nitride, titanium nitride, boron nitride, and other various inorganic oxides, nitrides, borides, and the like.

  Moreover, titanium coupling agents such as tetrabutyl titanate, tetraoctyl titanate, isopropyl triisostearoyl titanate, isopropyl tridecylbenzene sulfonyl titanate, bis (dioctyl pyrophosphate) oxyacetate titanate, γ- (2-amino) Ethyl) aminopropyltrimethoxysilane, γ- (2-aminoethyl) aminopropylmethyldimethoxysilane, γ-methacryloxypropyltrimethoxysilane, N-β- (N-vinylbenzylaminoethyl) γ-aminopropyltrimethoxysilane Hydrochloride, hexamethyldisilazane, methyltrimethoxysilane, butyltrimethoxysilane, isobutyltrimethoxysilane, hexyltrimethoxysilane, octyltrimethoxysilane The treatment may be performed with a silane coupling agent such as run, decyltrimethoxysilane, dodecyltrimethoxysilane, phenyltrimethoxysilane, o-methylphenyltrimethoxysilane, and p-methylphenyltrimethoxysilane. In addition, abrasive particles that have been subjected to a hydrophobic treatment with a higher fatty acid metal salt such as silicone oil, aluminum stearate, zinc stearate, calcium stearate, and the like can also be used.

The number average particle diameter of the abrasive particles is preferably 50 nm or more and 5000 nm or less, and more preferably 200 nm or more and 3000 nm or less.
The addition amount of the abrasive particles is preferably 0.1% by mass or more, more preferably 1.0% by mass or more based on the toner particles. When the addition amount of the abrasive is less than 0.1% by mass, the polishing effect may be insufficient, and various deposits on the surface of the image carrier may not be sufficiently removed. In addition, it is preferable that the addition amount of the abrasive is large from the viewpoint of sufficiently securing the polishing effect, but it is preferably 5.0% by mass or less for practical use.

In the present embodiment, the silica particles and the abrasive are preferably added to and mixed with the toner particles. For example, V-type blender, Henschel mixer, Redige mixer, Q-type mixer, hybridization It can be performed by a known mixer such as a system.
At this time, various additives may be added as necessary. Examples of the additive include other fluidizing agents, cleaning aids such as polystyrene fine particles, polymethyl methacrylate fine particles, and polyvinylidene fluoride fine particles, or transfer aids. Moreover, you may pass a sieving process after external addition mixing.

  The volume average particle size of the toner of the exemplary embodiment is preferably in the range of 3 to 9 μm, and more preferably in the range of 3 to 8 μm. When the volume average particle diameter of the toner particles exceeds 9 μm, the ratio of coarse particles increases, and the reproducibility and gradation of fine lines and fine dots of the image obtained through the fixing process are lowered. On the other hand, when the volume average particle size of the toner particles is less than 3 μm, the powder fluidity, developability, or transferability of the toner deteriorates, and the cleaning property of the toner remaining on the surface of the image carrier decreases. Various problems occur in other processes due to the deterioration of characteristics.

  Further, as the particle size distribution index of the toner of the present embodiment, the volume average particle size distribution index GSDv is preferably 1.30 or less, and the ratio GSDv / GSDp to the number average particle size distribution index GSDp is 0.95 or more. More preferably. When the volume distribution index GSDv exceeds 1.30, the resolution decreases, and when the ratio of the volume average particle size distribution index GSDv to the number average particle size distribution index GSDp is less than 0.95, a decrease in chargeability occurs. At the same time, it may scatter and cause image defects such as fog.

The volume average particle size and the particle size distribution index were measured and calculated as follows. First, with respect to the divided particle size range (channel) measured using Coulter Multisizer II (manufactured by Beckman-Coulter) as a measuring device, the volume and number of individual toner particles from the small diameter side. Draw a cumulative distribution, define the particle size to be 16% cumulative as volume average particle size D16v and number average particle size D16p, and set the particle size to 50% cumulative to volume average particle size D50v (this value is the volume average particle size). Defined as D50p). Similarly, the particle diameters with an accumulation of 84% are defined as volume average particle diameters D84v and D84p. Using these, the volume average particle size distribution index GSDv is defined as (D84v / D16v) ^1/2 , and the number average particle size distribution index GSDp is defined as (D84p / D16p) ^1/2 .

Furthermore, the toner shape factor SF1 in this embodiment is preferably in the range of 110-140.
Here, the shape factor SF1 is obtained by the following equation (2).
SF1 = (ML ² / A) × (π / 4) × 100 (2)
In the above formula (2), ML represents the absolute maximum length of the toner particles, and A represents the projected area of the toner particles.

  The SF1 is quantified mainly by analyzing a microscope image or a scanning electron microscope (SEM) image using an image analyzer, and can be calculated as follows, for example. That is, an optical microscope image of the toner spread on the surface of the slide glass is taken into a Luzex image analyzer through a video camera, the maximum length and projected area of 100 toner particles are obtained, calculated by the above equation (2), and the average value thereof Is obtained.

<Electrostatic image developer>
Next, the electrostatic charge image developer of the present invention will be described.
The electrostatic image developer of the present invention is not particularly limited except that it contains the toner of the present invention, and can have an appropriate component composition depending on the purpose. The developer of the present invention becomes a one-component developer when the toner is used alone, and becomes a two-component developer when the toner and carrier are used in combination.

Specific examples of the carrier include the following resin-coated carriers. Examples of the core material of the carrier include ordinary iron powder, ferrite, and magnetite molding, and the volume average particle size is in the range of about 30 to 200 μm.
The carrier core material preferably has a volume resistivity of 1 × 10 ^7.5 Ωcm or more and 1 × 10 ^9.5 Ωcm or less. When the volume resistivity is less than 1 × 10 ^7.5 Ω · cm, when the toner concentration in the developer is reduced by repeated copying, charges are injected into the carrier, and the carrier itself may be developed. is there. On the other hand, if the volume resistivity is higher than 1 × 10 ^9.5 Ω · cm, the image quality such as a prominent edge effect or pseudo contour may be adversely affected. The core material is not particularly limited as long as the above conditions are satisfied. For example, magnetic metals such as iron, steel, nickel, and cobalt, alloys of these with manganese, chromium, rare earth, and magnetic materials such as ferrite and magnetite. An oxide etc. are mentioned. Among these, ferrite, particularly an alloy with manganese, lithium, strontium, magnesium or the like is preferable from the viewpoint of core surface properties and core material resistance.

  The coating resin preferably contains at least a fluorine-based resin, and can be appropriately selected according to the purpose. However, fluorine-based resins such as polytetrafluoroethylene, polyvinyl fluoride, polyvinylidene fluoride, polychlorotrifluoroethylene, etc. Examples thereof include known resins such as resins. These may be used individually by 1 type and may use 2 or more types together.

  Moreover, it is preferable that at least resin particles and / or conductive particles are dispersed in the resin coating layer (coating film). When the resin particles are dispersed in the coating film, they are uniformly dispersed in the thickness direction and the tangential direction of the carrier surface. Surface formation similar to that at the time of use can be maintained, and good charge imparting ability for the toner can be maintained over a long period of time. Further, when conductive particles are dispersed in the coating film, since the conductive particles are uniformly dispersed in the thickness direction and the tangential direction of the carrier surface, the carrier film is used for a long period of time. Even when the surface is worn, it is possible to always maintain the same surface formation as when not in use, and to prevent carrier deterioration for a long time. In addition, when the resin particle and electroconductive particle are disperse | distributed to a coating film, the above-mentioned effect can be show | played simultaneously.

  Examples of the resin particles include thermoplastic resin particles and thermosetting resin particles. Among these, thermosetting resins are preferable from the viewpoint of relatively easily increasing the hardness, and resin particles made of nitrogen-containing resin containing N atoms are preferable from the viewpoint of imparting negative chargeability to the toner. In addition, these resin particles may be used individually by 1 type, and may use 2 or more types together. The average particle size of the resin particles is preferably about 0.1 μm to 2 μm, more preferably 0.2 μm to 1 μm. If the average particle size of the resin particles is less than 0.1 μm, the dispersibility of the resin particles in the coating film is very poor. On the other hand, if the average particle size exceeds 2 μm, the resin particles easily fall off from the coating film. It may not be effective. As conductive particles, metal particles such as gold, silver and copper, carbon black particles, semiconductive oxide particles such as titanium oxide and zinc oxide, titanium oxide, zinc oxide, barium sulfate, aluminum borate, potassium titanate Examples thereof include particles whose surface such as powder is covered with tin oxide, carbon black, metal or the like. These may be used individually by 1 type and may use 2 or more types together. Among these, carbon black particles are preferable from the viewpoints of production stability, cost, conductivity, and the like. The type of carbon black is not particularly limited, but carbon black having a DBP oil absorption of about 50 ml / 100 g or more and 250 ml / 100 g or less is preferable because of excellent production stability.

  Examples of the method for forming the resin coating layer on the surface of the core material include an immersion method in which the coating film-forming liquid containing the coating resin is immersed, a spray method in which the coating film forming liquid is sprayed on the surface of the carrier core material, and a carrier. Examples thereof include a kneader coater method in which the core material is mixed with a coating film forming liquid in a state where the core material is floated by flowing air, and the solvent is removed.

  The amount of the resin coating formed by the above method is used by coating an amount of 0.5% by mass or more and 10% by mass or less with respect to the carrier core material. The mixing ratio (mass ratio) of the toner and the carrier is preferably in the range of toner: carrier = 1: 100 to 30: 100, and more preferably in the range of 3: 100 to 20: 100.

<Image forming apparatus>
Next, the image forming apparatus of the present invention using the electrostatic image developing toner of the present invention will be described.
The image forming apparatus of the present invention includes an image carrier, a developing unit that develops an electrostatic image formed on the image carrier as a toner image with a developer, and a toner image formed on the image carrier. The image forming apparatus includes a transfer unit that transfers onto a transfer body and a fixing unit that fixes a toner image transferred onto the transfer body, and uses the electrostatic image developer of the present invention as the developer.

In this image forming apparatus, for example, the part including the developing unit may have a cartridge structure (process cartridge) that can be attached to and detached from the image forming apparatus main body. As the process cartridge, a developer holding body is used. The process cartridge of the present invention that contains at least the electrostatic image developer of the present invention is preferably used.
Hereinafter, an example of the image forming apparatus of the present invention will be shown, but the present invention is not limited to this. In addition, the main part shown to a figure is demonstrated and the description is abbreviate | omitted about others.

  FIG. 1 is a schematic diagram showing a quadruple tandem full-color image forming apparatus. The image forming apparatus shown in FIG. 1 is a first to first electrophotographic method that outputs yellow (Y), magenta (M), cyan (C), and black (K) images based on color-separated image data. Fourth image forming units 10Y, 10M, 10C, and 10K (image forming means) are provided. These image forming units (hereinafter simply referred to as “units”) 10Y, 10M, 10C, and 10K are juxtaposed at a predetermined distance in the horizontal direction. The units 10Y, 10M, 10C, and 10K may be process cartridges that are detachable from the main body of the image forming apparatus.

Above each of the units 10Y, 10M, 10C, and 10K, an intermediate transfer belt 20 as an intermediate transfer member is extended through each unit. The intermediate transfer belt 20 is provided by being wound around a driving roller 22 and a support roller 24 that are in contact with the inner surface of the intermediate transfer belt 20 that are spaced apart from each other from the left to the right in the drawing. It is designed to travel in the direction toward 10K. The support roller 24 is biased in a direction away from the drive roller 22 by a spring or the like (not shown), and a predetermined tension is applied to the intermediate transfer belt 20 wound around both. Further, an intermediate transfer member cleaning device 30 is provided on the side of the image carrier of the intermediate transfer belt 20 so as to face the driving roller 22.
Further, each of the developing devices (developing means) 4Y, 4M, 4C, and 4K of the units 10Y, 10M, 10C, and 10K includes yellow, magenta, cyan, and black contained in the toner cartridges 8Y, 8M, 8C, and 8K. The four color toners can be supplied.

  Since the first to fourth units 10Y, 10M, 10C, and 10K described above have the same configuration, here, the first unit that forms a yellow image disposed on the upstream side in the intermediate transfer belt traveling direction. 10Y will be described as a representative. Note that the second to fourth units are denoted by reference numerals with magenta (M), cyan (C), and black (K) instead of yellow (Y) in the same parts as the first unit 10Y. Description of 10M, 10C, 10K is omitted.

The first unit 10Y has a photoreceptor 1Y that functions as an image holding member. Around the photoreceptor 1Y, an electrostatic charge image is formed by exposing the surface of the photoreceptor 1Y to a predetermined potential with a charging roller 2Y and the charged surface with a laser beam 3Y based on the color-separated image signal. An exposure device 3; a developing device (developing means) 4Y for supplying the charged toner to the electrostatic image and developing the electrostatic image; a primary transfer roller 5Y (primary) for transferring the developed toner image onto the intermediate transfer belt 20; A transfer unit), and a photoconductor cleaning device (cleaning unit) 6Y for removing toner remaining on the surface of the photoconductor 1Y after the primary transfer with a cleaning blade.
The primary transfer roller 5Y is disposed inside the intermediate transfer belt 20, and is provided at a position facing the photoreceptor 1Y. Further, a bias power source (not shown) for applying a primary transfer bias is connected to each of the primary transfer rollers 5Y, 5M, 5C, and 5K. Each bias power source varies the transfer bias applied to each primary transfer roller under the control of a control unit (not shown).

Hereinafter, an operation of forming a yellow image in the first unit 10Y will be described. First, prior to the operation, the surface of the photoreceptor 1Y is charged to a potential of about −600V to −800V by the charging roller 2Y.
The photoreceptor 1Y is formed by laminating a photosensitive layer on a conductive substrate (volume resistivity at 20 ° C .: 1 × 10 ⁻⁶ Ωcm or less). This photosensitive layer usually has a high resistance (a resistance equivalent to that of a general resin), but has a property that the specific resistance of the portion irradiated with the laser beam changes when irradiated with the laser beam 3Y. Therefore, a laser beam 3Y is output to the surface of the charged photoreceptor 1Y via the exposure device 3 in accordance with yellow image data sent from a control unit (not shown). The laser beam 3Y is applied to the photosensitive layer on the surface of the photoreceptor 1Y, whereby an electrostatic charge image of a yellow print pattern is formed on the surface of the photoreceptor 1Y.

The electrostatic charge image is an image formed on the surface of the photoreceptor 1Y by charging, and the specific resistance of the irradiated portion of the photosensitive layer is lowered by the laser beam 3Y, and the charged charge on the surface of the photoreceptor 1Y flows. On the other hand, this is a so-called negative latent image formed by the charge remaining in the portion not irradiated with the laser beam 3Y.
The electrostatic image formed on the photoreceptor 1Y in this way is rotated to a predetermined development position as the photoreceptor 1Y travels. At this development position, the electrostatic charge image on the photoreceptor 1Y is visualized (developed image) by the developing device 4Y.

  In the developing device 4Y, for example, yellow toner having a volume average particle diameter of 7 μm including at least a yellow colorant, a crystalline resin, and an amorphous resin is accommodated. The yellow toner is triboelectrically charged by being agitated inside the developing device 4Y, and has a charge of the same polarity (negative polarity) as the charged charge on the photoreceptor 1Y, and a developer roll (developer holder). Is held on. As the surface of the photoreceptor 1Y passes through the developing device 4Y, the yellow toner is electrostatically attached to the latent image portion on the surface of the photoreceptor 1Y, and the latent image is developed with the yellow toner. . The photoreceptor 1Y on which the yellow toner image is formed continues to run at a predetermined speed, and the toner image developed on the photoreceptor 1Y is conveyed to a predetermined primary transfer position.

When the yellow toner image on the photoreceptor 1Y is conveyed to the primary transfer, a predetermined primary transfer bias is applied to the primary transfer roller 5Y, and the electrostatic force directed from the photoreceptor 1Y to the primary transfer roller 5Y generates a toner image. The toner image on the photoreceptor 1 </ b> Y is transferred onto the intermediate transfer belt 20. The transfer bias applied at this time is a (+) polarity opposite to the polarity (−) of the toner, and is controlled to about +10 μA by the control unit (not shown) in the first unit 10Y, for example.
On the other hand, the toner remaining on the photoreceptor 1Y is removed and collected by the cleaning device 6Y.

Further, the primary transfer bias applied to the primary transfer rollers 5M, 5C, and 5K after the second unit 10M is also controlled according to the first unit.
Thus, the intermediate transfer belt 20 onto which the yellow toner image has been transferred by the first unit 10Y is sequentially conveyed through the second to fourth units 10M, 10C, and 10K, and the toner images of the respective colors are superimposed and transferred in a multiple manner.

  The intermediate transfer belt 20 onto which the four color toner images have been transferred in multiple layers through the first to fourth units is disposed on the image transfer surface side of the intermediate transfer belt 20 and the support roller 24 in contact with the inner surface of the intermediate transfer belt 20. The secondary transfer roller (secondary transfer means) 26 is connected to a secondary transfer portion. On the other hand, the recording paper (transfer object) P is fed at a predetermined timing into a gap where the secondary transfer roller 26 and the intermediate transfer belt 20 are pressed against each other via a supply mechanism, and a predetermined secondary transfer bias is supported. Applied to the roller 24. The transfer bias applied at this time is a (−) polarity that is the same polarity as the polarity (−) of the toner, and an electrostatic force from the intermediate transfer belt 20 toward the recording paper P is applied to the toner image, and the transfer bias is applied to the intermediate transfer belt 20. The toner image is transferred onto the recording paper P. Note that the secondary transfer bias at this time is determined according to the resistance detected by a resistance detecting means (not shown) for detecting the resistance of the secondary transfer portion, and is voltage-controlled.

Thereafter, the recording paper P is sent to a fixing device (fixing means) 28, where the toner image is heated, and the color-superposed toner image is melted and fixed on the recording paper P. The recording paper P on which the color image has been fixed is carried out toward the discharge unit, and a series of color image forming operations is completed.
The image forming apparatus exemplified above is configured to transfer the toner image onto the recording paper P via the intermediate transfer belt 20, but the present invention is not limited to this configuration, and the toner image is directly transferred from the photoconductor. It may be a structure that is transferred to a recording sheet.

<Process cartridge, toner cartridge>
FIG. 2 is a schematic configuration diagram showing a preferred example of a process cartridge containing the electrostatic charge image developer of the present invention. The process cartridge 200 includes, together with the photoconductor 107, a charging roller 108, a developing device 111, a photoconductor cleaning device (cleaning means) 113 including a cleaning blade, an opening 118 for exposure, and an opening for static elimination exposure. 117 is combined and integrated using mounting rails 116.
The process cartridge 200 is detachable from an image forming apparatus main body including a transfer device 112, a fixing device 115, and other components (not shown). It forms a forming apparatus. Reference numeral 300 denotes a recording sheet.

  The process cartridge shown in FIG. 2 includes a charging device 108, a developing device 111, a cleaning device (cleaning means) 113, an opening 118 for exposure, and an opening 117 for static elimination exposure. Can be selectively combined. In the process cartridge of the present invention, in addition to the photosensitive member 107, from the charging device 108, the developing device 111, the cleaning device (cleaning means) 113, the opening 118 for exposure, and the opening 117 for static elimination exposure. It comprises at least one selected from the group consisting of.

  Next, the toner cartridge of the present invention will be described. The toner cartridge of the present invention is detachably attached to the image forming apparatus, and at least the toner cartridge for storing toner to be supplied to the developing means provided in the image forming apparatus, the toner described above. Toner. The toner cartridge of the present invention only needs to contain at least toner, and may contain developer, for example, depending on the mechanism of the image forming apparatus.

  Therefore, in an image forming apparatus having a configuration in which a toner cartridge can be attached and detached, the storage stability can be maintained even in a toner cartridge whose container is miniaturized by using the toner cartridge containing the toner of the present invention. This makes it possible to achieve low-temperature fixing while maintaining high image quality.

  The image forming apparatus shown in FIG. 1 is an image forming apparatus having a configuration in which the toner cartridges 8Y, 8M, 8C, and 8K can be attached and detached, and the developing devices 4Y, 4M, 4C, and 4K are respectively the developing devices ( And a toner supply pipe (not shown). Further, when the amount of toner stored in the toner cartridge is low, the toner cartridge can be replaced.

EXAMPLES Hereinafter, the present invention will be specifically described with reference to examples, but the present invention is not limited to these examples. However, Examples 1 to 5 and 8 to 9 correspond to reference examples.
In the following description, “part” and “%” all mean “part by mass” and “% by mass” unless otherwise specified.

<Measuring method of various characteristics>
First, a method for measuring physical properties of toners and the like used in Examples and Comparative Examples (excluding the method described above) will be described.
(Measurement method of molecular weight and molecular weight distribution of resin)
The molecular weight and molecular weight distribution of the binder resin and the like are performed under the following conditions. GPC uses “HLC-8120GPC, SC-8020 (manufactured by Tosoh Corporation)”, and the column uses two “TSKgel, SuperHM-H (6.0 mm ID × 15 cm, manufactured by Tosoh Corporation)” THF (tetrahydrofuran) was used as an eluent. As experimental conditions, an experiment was performed using a sample concentration of 0.5%, a flow rate of 0.6 ml / min, a sample injection amount of 10 μl, a measurement temperature of 40 ° C., and an IR detector. The calibration curve is “polystylen standard sample TSK standard” manufactured by Tosoh Corporation: “A-500”, “F-1”, “F-10”, “F-80”, “F-380”, “A-2500”. ”,“ F-4 ”,“ F-40 ”,“ F-128 ”, and“ F-700 ”.
The data collection interval in sample analysis was 300 ms.

(Volume average particle diameter of resin particles, colorant particles, etc.)
Volume average particle diameters of resin particles, colorant particles, and the like were measured with a laser diffraction particle size distribution measuring apparatus (LA-700, manufactured by Horiba, Ltd.).

(Glass transition temperature and melting temperature of resin)
The glass transition temperature (Tg) and melting temperature of the binder resin, etc. are from 25 ° C. to 150 ° C. using a differential scanning calorimeter (manufactured by Shimadzu Corporation: DSC60, with automatic tangential processing system) in accordance with ASTM D3418-8. It calculated | required by measuring on conditions with a temperature increase rate of 10 degree-C / min. The glass transition temperature was the temperature at the intermediate point in the stepwise endothermic change, and the melting temperature (is the peak temperature of the endothermic peak).

(Volume average primary particle size of external additive)
The measurement was performed using a laser diffraction / scattering particle size distribution analyzer (Mastersizer 2000, manufactured by Malvern).
As a measurement method, a sample in a dispersion is adjusted to have a solid content of about 2 g, and ion exchange water is added thereto to make about 40 ml. This is put into the cell until an appropriate concentration is reached, waits for about 2 minutes, and is measured when the concentration in the cell becomes almost stable. With respect to the obtained volume particle size distribution for each channel, the volume average particle size is defined as the volume average particle size at which 50% is accumulated from the smaller particle size, and this is defined as the volume average primary particle size of the external additive particles.

  When measuring each particle such as external additive particles, 2 g of a measurement sample is added to 50 ml of a 5% aqueous solution of a surfactant, preferably sodium alkylbenzenesulfonate, and 2 minutes with an ultrasonic disperser (1000 Hz). A sample was prepared by dispersing, and the sample was measured in the same manner as the above dispersion.

(Free amount of external additive)
The method for determining the amount of free oil of the external additive from the toner will be described below, but it can of course be determined from the external additive alone.
2 g of toner is added to 40 ml of an aqueous solution of 0.2% surfactant (polyoxyethylene (10) octylphenyl ether having a polyoxyethylene polymerization degree of 10 manufactured by Wako Pure Chemical Industries, Ltd.) so that the toner gets wet with the aqueous solution. Disperse thoroughly. In this state, an ultrasonic homogenizer US300T (manufactured by Nippon Seiki Seisakusho) was used, and ultrasonic vibration with an output of 20 W and a frequency of 20 kHz was applied for 1 minute to desorb the external additive particles. Thereafter, the toner is separated under conditions of 3000 rpm × 7 minutes through a 50 ml centrifuge with a sedimentation tube (compact cooling high-speed centrifuge Model M160 IV, manufactured by Sakuma Seisakusho Co., Ltd.), and the supernatant liquid is separated into a membrane filter (Nippon Millipore After removal with FHLP02500), the membrane was further removed with a membrane filter having a pore size of 0.22 μm (GSEP047SO) and a pore size of 0.025 μm (VSWP02500), and then the furnace liquid was dried. If the sample amount required for measurement could not be recovered, the same operation was repeated until the sample amount required for measurement could be recovered. NMR measurement was performed using 10 mg of the dried residue.

  Proton NMR was measured using AL-400 (magnetic field 9.4T (H nucleus 400 MHz)) manufactured by JEOL. A sample, a deuterated chloroform solvent, and TMS as a reference substance are filled into a sample tube (diameter 5 mm) made of zirconia. This sample tube is set, and for example, measurement is performed at a frequency: Δ87 kHz / 400 MHz (= Δ20 ppm), measurement temperature: 25 ° C., integration number: 16 times, resolution 0.24 Hz (about 32000 points), free surface treatment agent It converted into the amount of free surface treating agents using the analytical curve from the peak intensity of origin. For example, when dimethyl silicone oil is used as the free surface treatment agent, NMR measurement is performed on the untreated external additive base material and dimethyl silicone oil (shake about 5 levels), and the amount of free surface treatment agent And a calibration curve of NMR peak intensity.

<Preparation of toner particles>
(Preparation of each dispersion)
-Crystalline resin dispersion-
In a heat-dried three-necked flask, an acidic component composed of 98 mol% dimethyl sebacate and 2 mol% dimethyl-5-sulfonate sodium and an alcohol component composed of ethylene glycol were added at a molar ratio of 1: 1. After adding 0.3 part of dibutyltin oxide as a catalyst to 100 parts of the above, the air in the container was put into an inert atmosphere with nitrogen gas by depressurization and stirred and refluxed at 180 ° C. for 5 hours with mechanical stirring. Went.
Thereafter, the temperature was gradually raised to 230 ° C. under reduced pressure, and the mixture was stirred for 2 hours. When it became viscous, it was air-cooled, the reaction was stopped, and a crystalline polyester resin was synthesized. It was 9700 when the weight average molecular weight Mw of the obtained crystalline polyester resin was confirmed by the molecular weight measurement (polystyrene conversion) by gel permeation chromatography. The melting temperature was 72 ° C.

-Crystalline polyester resin: 90 parts-Ionic surfactant (Neogen RK, Daiichi Kogyo Seiyaku): 1.8 parts-Ion-exchanged water: 210 parts The above was heated to 100 ° C and a homogenizer (manufactured by IKA, After sufficiently dispersing with Ultra Turrax T50), dispersion treatment was performed for 1 hour with a pressure discharge type gorin homogenizer to obtain a crystalline resin dispersion having a volume average particle size of 200 nm and a solid content of 20%.

-Amorphous resin dispersion-
・ Terephthalic acid: 30 mol%
・ Fumaric acid: 70 mol%
-Bisphenol A ethylene oxide 2-mol adduct: 20 mol%
-Bisphenol A propylene oxide adduct: 80 mol%
Into a 5 liter flask equipped with a stirrer, nitrogen inlet tube, temperature sensor, rectifying column, charged with a monomer having the above-mentioned molar ratio of the acid component and alcohol component, the temperature was raised to 190 ° C. over 1 hour, After confirming that the reaction system was uniformly stirred, 1.2 parts of dibutyltin oxide was added to 100 parts of the monomer mixture. Further, while distilling off the water produced, it took 6 hours from the same temperature to increase the temperature to 240 ° C., and continued the dehydration condensation reaction at 240 ° C. for another 3 hours, with an acid value of 12.0 mg / KOH, weight average molecular weight Of 9700 and a glass transition temperature of 61 ° C. were obtained.

Subsequently, this was transferred in a molten state to Cavitron CD1010 (manufactured by Eurotech Co., Ltd.) at a rate of 100 g / min. Separately prepared aqueous medium tank is filled with 0.37% dilute aqueous ammonia diluted with reagent-exchanged ammonia water with ion-exchanged water, heated at 120 ° C. with a heat exchanger at a rate of 0.1 liter per minute, The amorphous polyester resin melt was transferred to Cavitron CD1010 at the same time.
The Cavitron was operated under conditions of a rotor rotation speed of 60 Hz and a pressure of 5 kg / cm 2 to obtain an amorphous resin dispersion having a volume average particle size of 0.16 μm and a solid content of 30%.

-Colorant dispersion-
Cyan pigment (Daiichi Seika Co., Ltd., CI Pigment Blue 15: 3 (copper phthalocyanine)): 45 parts Ionic surfactant (Neogen RK, Daiichi Kogyo Seiyaku): 5 parts Ion exchange Water: 200 parts or more of the above was mixed and dissolved, and dispersed for 10 with a homogenizer (manufactured by IKA, Ultra Tarrax T50) to obtain a colorant dispersion having a volume average particle size of 168 nm and a solid content of 22.0%.

-Release agent dispersion-
Paraffin wax (HNP9, manufactured by Nippon Seiki, melting temperature: 75 ° C): 45 parts Cationic surfactant (Neogen RK, Daiichi Kogyo Seiyaku): 5 parts Ion-exchanged water: 200 parts After heating to 0 ° C. and sufficiently dispersing with a homogenizer (IKA Corp., Ultra Tarrax T50), it is dispersed with a pressure discharge type gorin homogenizer, and the volume average particle size is 200 nm and the solid content is 20.0%. A mold dispersion was obtained.

(Production of toner particles)
-Toner particles 1-
Amorphous resin resin dispersion: 256.7 parts Crystalline resin dispersion: 33.3 parts Colorant dispersion: 27.3 parts Release agent dispersion: 35 parts The above is a round stainless steel flask The mixture was thoroughly mixed and dispersed with Ultra Turrax T50. Next, 0.20 part of polyaluminum chloride was added thereto, and the dispersion operation was continued with an Ultra Talux T50. The flask was heated to 48 ° C. with stirring in an oil bath for heating and maintained at this temperature for 60 minutes, and then 70.0 parts of the amorphous resin dispersion was gradually added thereto.

Thereafter, the pH of the system was adjusted to 9.0 with a 0.5 mol / l sodium hydroxide aqueous solution, and then the stainless steel flask was sealed and heated to 96 ° C. while continuing to stir using a magnetic seal for 5 hours. Retained. After completion of the reaction, the mixture was cooled, filtered, sufficiently washed with ion exchange water, and then subjected to solid-liquid separation by Nutsche suction filtration. This was further redispersed in 1 liter of ion-exchanged water at 40 ° C., and stirred and washed at 300 rpm for 15 minutes. This was repeated five more times, and when the pH of the filtrate was 7.5 and the electric conductivity was 7.0 μS / cm, solid-liquid separation was performed using No5A filter paper by Nutsche suction filtration. Vacuum drying was then continued for 12 hours.
When the particle size at this time was measured with a Coulter Multisizer, the volume average particle size was 5.9 μm and the volume particle size distribution index GSDv was 1.24. Moreover, it was observed that the shape factor of the particle | grains calculated | required by shape observation with a Luzex image analyzer is 130.

-Toner particles 2-
Toner particles 2 were prepared in the same manner as toner particles 1 except that in the preparation of toner particles 1, an amorphous resin dispersion was used instead of the crystalline resin dispersion.

<Preparation of external additive>
(Preparation of silica particles)
-Silica particles (1)-
Silica particles (1) having a surface treatment amount of 5% by mass and an average primary particle size of 130 nm were prepared by a sol-gel method. The amount of free oil of the silica particles (1) was 2.5% by mass.

-Production of silica particles (2)-
Silica particles (2) having a surface treatment amount of 5% by mass and an average primary particle size of 65 nm were prepared by a sol-gel method. The amount of free oil of the silica particles (2) was 2.5% by mass.

-Production of silica particles (3)-
By a sol-gel method, silica particles (3) having a surface treatment amount of 3% by mass with dimethyl silicone oil and an average primary particle size of 130 nm were prepared. The amount of free oil of the silica particles (3) was 0.3% by mass.

-Production of silica particles (4)-
By the sol-gel method, silica particles (4) having a surface treatment amount of 3% by mass with dimethyl silicone oil and an average primary particle size of 65 nm were prepared. The amount of free oil of the silica particles (4) was 0.3% by mass.

-Production of silica particles (5)-
Silica particles (5) having a surface treatment amount of 5% by mass and an average primary particle size of 180 nm were prepared by a sol-gel method. The amount of free oil of the silica particles (5) was 2.5% by mass.

-Production of silica particles (6)-
Silica particles (6) having a surface treatment amount of dimethyl silicone oil of 5% by mass and an average primary particle size of 35 nm were prepared by the sol-gel method. The amount of free oil of the silica particles (6) was 2.5% by mass.

-Production of silica particles (7)-
Silica particles (7) having a surface treatment amount of 10% by mass and an average primary particle size of 130 nm were prepared by a sol-gel method. The amount of free oil of the silica particles (7) was 4.5% by mass.

-Production of silica particles (8)-
Silica particles (8) having a surface treatment amount of dimethyl silicone oil of 0.5 mass% and an average primary particle size of 130 nm were prepared by the sol-gel method. The amount of free oil of the silica particles (8) was 0.08% by mass.

(Preparation of negatively charged silica)
-Negatively chargeable silica A-
100 parts of silica particles (1) and 500 parts of ethanol were placed in an evaporator and stirred for 15 minutes while maintaining the temperature at 40 ° C. Next, 10 parts of dimethyldimethoxysilane was added to 100 parts of silica particles, and the mixture was further stirred for 15 minutes. Finally, the temperature was raised to 90 ° C. and ethanol was dried under reduced pressure. Thereafter, the treated product was taken out and further vacuum-dried at 120 ° C. for 30 minutes. The dried silica was pulverized to obtain negatively charged silica A.

-Negatively charged silica B to H-
The negatively chargeable silica A was prepared in the same manner as the negatively chargeable silica A, except that each of the silica particles (2) to (8) was used instead of the silica particles (1) in the preparation of the negatively chargeable silica A. B to H were produced.

(Preparation of positively charged silica)
-Positively chargeable silica A-
In preparation of the negatively chargeable silica A, untreated silica having an average primary particle size of 230 nm obtained by the sol-gel method was used in place of the silica particles (1), and γ-aminosilane was used in place of dimethyldimethoxysilane as a treating agent. Except for the above, positively charged silica A was obtained in the same manner as in the preparation of negatively charged silica A.

-Positively chargeable silica B-
In the production of the negatively chargeable silica A, untreated silica having an average primary particle size of 180 nm obtained by the sol-gel method was used in place of the silica particles (1), and γ-aminosilane was used in place of dimethyldimethoxysilane as a treating agent. Except for the above, positively charged silica B was obtained in the same manner as in the preparation of negatively charged silica A.

-Positively chargeable silica C-
In preparation of the negatively chargeable silica A, untreated silica having an average primary particle size of 120 nm obtained by the sol-gel method was used in place of the silica particles (1), and γ-aminosilane was used in place of dimethyldimethoxysilane as a treating agent. Except for the above, positively charged silica C was obtained in the same manner as in the preparation of negatively charged silica A.

-Positively chargeable silica D-
In preparation of the negatively chargeable silica A, untreated silica having an average primary particle size of 280 nm obtained by the sol-gel method was used in place of the silica particles (1), and γ-aminosilane was used in place of dimethyldimethoxysilane as a treating agent. Except for the above, a positively chargeable silica D was obtained in the same manner as the preparation of the negatively chargeable silica A.

(Preparation of titanium oxide particles)
Using ilmenite as an ore, TiO (OH) ₂ was produced using a wet precipitation method in which iron powder was separated by dissolving in sulfuric acid and TiOSO ₄ was hydrolyzed to produce TiO (OH) ₂ . In the process of producing TiO (OH) ₂ , dispersion adjustment and water washing for hydrolysis and nucleation were performed.

100 parts of TiO (OH) ₂ obtained in 1000 ml of water was dispersed, and 20 parts of isobutyltrimethoxysilane was added dropwise thereto while stirring at room temperature. Subsequently, this was filtered and water washing was repeated. Then, the titanium oxide surface-hydrophobized with isobutyltrimethoxysilane is dried at 150 ° C., and the average primary particle size is 30 nm, the BET specific surface area is 120 m ² / g, and the specific gravity is 3.4. Titanium particles were prepared.

<Preparation of external toner>
(External toner 1-1)
To toner particles 1: 100 parts, 2.0 parts of negatively charged silica A and 0.1 part of cerium oxide E10 (Mitsui Metals, average particle size: 500 nm) are added, and 10 parts at 2500 rpm with a Henschel mixer. An externally added toner 1-1 was prepared by processing for a minute.

(Externally added toner 1-2 to 1-9)
In preparation of the externally added toner 1-1, negatively charged silicas B to H are used instead of the negatively charged silica A (externally added toners 1-2 to 1-8), and titanium oxide particles having an average particle diameter of 30 nm are further used. External additive toners 1-2 to 1-9 were prepared in the same manner as external additive toner 1-1 except that (external toner 1-9) was used.

(External toner 1-10)
External toner 1-10 was prepared in the same manner as external toner 1-1 except that only negatively chargeable silica A was used as the external additive in preparation of external additive toner 1-1.

(External toner 1-11)
External toner 1-11 was prepared in the same manner as external toner 1-1 except that toner particles 2 were used instead of toner particles 1 in preparation of external toner 1-1.

(External toner 2-1)
Toner particles 1: 1 part of negatively chargeable silica A, 1 part of positively chargeable silica A, and 0.1 part of cerium oxide E10 (Mitsui Metals, average particle size: 500 nm) as an abrasive The mixture was then added and stirred for 10 minutes at 2500 rpm with a Henschel mixer to prepare externally added toner 2-1.

(External toner 2-2)
Toner particles 1: 1 part of negatively chargeable silica B, 1 part of positively chargeable silica B and 0.1 part of cerium oxide E10 are added to 100 parts of toner particles, and the mixture is stirred for 10 minutes at 2500 rpm with a Henschel mixer. Added toner 2-2 was prepared.

(External toner 2-3)
Toner particles 1: 1 part of negatively-charged silica A, 1 part of positively-charged silica C and 0.1 part of cerium oxide E10 are added to 100 parts of toner particles, and the mixture is stirred for 10 minutes at 2500 rpm with a Henschel mixer. Added toner 2-3 was prepared.

(External toner 2-4)
Toner particles 1: 1 part of negatively chargeable silica A, 1 part of positively chargeable silica D and 0.1 part of cerium oxide E10 are added to 100 parts of toner particles, and the mixture is stirred for 10 minutes at 2500 rpm with a Henschel mixer. Added toner 2-4 was produced.

(External toner 2-5)
Toner particles 1: 1 part of negatively chargeable silica G, 1 part of positively chargeable silica A and 0.1 part of cerium oxide E10 are added to 100 parts of toner particles, and the mixture is stirred for 10 minutes at 2500 rpm with a Henschel mixer. Added toner 2-5 was produced.

(External toner 2-6)
Toner particles 1: 1 part of negatively-charged silica H, 1 part of positively-charged silica A and 0.1 part of cerium oxide E10 are added to 100 parts of toner particles, and the mixture is stirred for 10 minutes at 2500 rpm with a Henschel mixer. Added toner 2-6 was produced.

(External toner 2-7)
Toner particles 1: 1 part of negatively chargeable silica E, 1 part of positively chargeable silica A and 0.1 part of cerium oxide E10 are added to 100 parts of toner particles, and the mixture is stirred for 10 minutes at 2500 rpm with a Henschel mixer. Added toner 2-7 was produced.

(External toner 2-8)
Toner particles 1: 1 part of negatively chargeable silica F, 1 part of positively chargeable silica A and 0.1 part of cerium oxide E10 are added to 100 parts of toner particles, and the mixture is stirred for 10 minutes at 2500 rpm with a Henschel mixer. Added toner 2-8 was produced.

(External toner 3-1)
To the toner particles 1: 100 parts, 1 part of positively charged silica A and 0.1 part of cerium oxide E10 were added, and the mixture was stirred with a Henschel mixer at 2500 rpm for 10 minutes to prepare externally added toner 2-5. .

<Creation of carrier>
Ferrite particles (volume average particle diameter: 50 μm, volume resistivity: 3 × 10 ⁸ Ωcm): 100 parts Toluene: 14 parts Perfluorooctylethyl acrylate / methyl methacrylate copolymer (copolymerization ratio: 40/60, Mw: 50,000): 1.6 parts Carbon black (VXC-72, manufactured by Cabot Corporation): 0.12 parts Cross-linked melamine resin (number average particle size: 0.3 μm): 0.3 parts Among the above components The components excluding the ferrite particles are dispersed with a stirrer for 10 minutes to prepare a film-forming liquid. The film-forming liquid and the ferrite particles are placed in a vacuum degassing kneader and stirred at 60 ° C. for 30 minutes, and then the pressure is reduced. Then, toluene was distilled off, and a resin film was formed on the surface of the ferrite particles to produce a carrier.

<Production of developer>
The externally added toner 1-1: 4 parts and 96 parts of the carrier were mixed and stirred with a V-type blender for 5 minutes to prepare a developer (1).
The other externally added toners were similarly mixed with a carrier to produce a developer.

<Example 1>
As an image forming apparatus, a DocuCentreColor400CP (Fuji Xerox Co., Ltd.) remodeled machine was prepared, and the following evaluation was performed.
(Fixation evaluation)
The image forming apparatus is filled with the developer (1), the developing condition is set to 15.0 g / m ² in terms of toner loading, and C2 paper (manufactured by Fuji Xerox Co., Ltd.) is used. A 4 cm solid image was formed. At this time, the fixing device was modified so that the fixing temperature in the image forming apparatus was fixed at 150 ° C., and 10 sheets were printed continuously. The fixability of these images was evaluated according to the following evaluation criteria.
○: No problem for all images.
×: Offset occurs when more than 1 sheet.

(Image quality evaluation)
Using the image forming apparatus, an image was formed using a gradation chart of four colors. This gradation chart is an A4 size chart having an image density of 20% for each color, and the gradation part has a solid part, a halftone part, and a background part, respectively. In a high temperature and high humidity environment (28 ° C., 80% RH), printing was performed up to 10,000 sheets, and whether or not color points, fogging, and color streaks occurred was evaluated according to the following criteria.

-Color point-
○: No color point is observed.
X: A color point is generated.
-Fogging-
The density was measured with an image densitometer X-Rite 938 (manufactured by X-Rite) for the background portion, and the following standards were used.
○: The fog density is less than 0.2, and no partial fog is observed even visually.
Δ: The fog density is less than 0.2, but partial fog is visually observed. X: The fog density is 0.2 or more.
-Color streaks-
○: No color streak is seen.
Δ: Slight streaks are observed, but there is no problem in quality.
X: Color streak that causes a quality problem.

(Photoconductor wear)
For the photoconductor after printing 10,000 sheets, the thermal deflection temperature was measured at 10 points according to HDT0.45Mpa (ISO75-2) with an eddy current film thickness meter, and the photoconductor wear rate was calculated from the average value of the wear amount. The evaluation was made according to the following criteria.
A: The wear rate is 50 nm / 1000 sheets, and the surface is not changed.
Δ: Wear rate is 50 nm / 1000 sheets, but slight streaks are observed on the surface.
X: Abrasion rate is 50 nm / 1000 sheets or more.
The above evaluation results are summarized in Table 1.

<Examples 2-9, Comparative Examples 1-11>
Evaluations were made in the same manner as in Example 1 except that each of the developers containing the externally added toner shown in Table 1 was used instead of the developer (1). The results are summarized in Table 1.

  From the results of Table 1, it can be seen that the toner of the example in which silica with a small amount of free oil in a specific particle size range is externally added is excellent not only in fixability but also in image quality stability and there is no problem with photoreceptor wear. . On the other hand, in the comparative example not satisfying any of the above-described configurations, a problem occurred in some characteristics.

1 is a schematic configuration diagram illustrating an example of an image forming apparatus of the present invention. It is a schematic block diagram which shows an example of the process cartridge of this invention.

Explanation of symbols

1Y, 1M, 1C, 1K, 107 photoconductor (image carrier)
2Y, 2M, 2C, 2K, 108 Charging roller 3Y, 3M, 3C, 3K Laser beam 3, 110 Exposure device 4Y, 4M, 4C, 4K, 111 Developing device (developing means)
5Y, 5M, 5C, 5K Primary transfer rollers 6Y, 6M, 6C, 6K, 113 Photoconductor cleaning device (cleaning means)
8Y, 8M, 8C, 8K Toner cartridge 10Y, 10M, 10C, 10K Unit 20 Intermediate transfer belt 22 Drive roller 24 Support roller 26 Secondary transfer roller (transfer means)
28, 115 Fixing device (fixing means)
30 Intermediate transfer member cleaning device 112 Transfer device 116 Mounting rail 117 Opening portion 118 for static elimination exposure Opening portion 200 for exposure Process cartridge P, 300 Recording paper (transfer object)

Claims (5)

Toner particles comprising a crystalline resin and a colorant;
Negatively chargeable silica particles having an average primary particle size of 50 nm or more and 150 nm or less treated with silicone oil;
Positively chargeable silica particles having an average primary particle size of 150 nm or more and 250 nm or less;
Abrasive particles,
Containing
A negatively charged toner for developing an electrostatic image, wherein the amount of free oil of the negatively chargeable silica particles is from 0.1% by mass to 3% by mass. An electrostatic image developer comprising: a toner, wherein the toner is the negatively charged toner for developing an electrostatic image according to claim 1 . A toner cartridge comprising at least a toner, wherein the toner is the negatively charged toner for developing an electrostatic image according to claim 1 . A process cartridge comprising at least a developer holder and containing the electrostatic charge image developer according to claim 2 . An image carrier, a developing unit that develops an electrostatic image formed on the image carrier as a toner image with a developer, and a transfer unit that transfers the toner image formed on the image carrier onto a transfer target An image forming apparatus comprising: a fixing unit configured to fix a toner image transferred onto a transfer target; and the developer is the electrostatic charge image developer according to claim 2 .

Images