JP2007187873A - Toner and image forming method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a toner which does not give rise to degradation (increasing of a fog) in developability and lowering of transfer efficiency even in long-term use and is excellent in characteristics to suppress or prevent the occurrence of an image flow during image formation even under a highly moist environment. <P>SOLUTION: The toner contains colored particles containing at least a binder resin and a colorant, and an external additive, in which the external additive contains at least two kinds of non-crystalline inorganic particulates (A) of 80 to 300 nm in average primary grain size Da and crystalline inorganic particulates (B) of 80 to 300 nm in average primary grain size Db. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

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

  The present invention also relates to developing an electrostatic latent image formed on an electrostatic latent image carrier such as an electrophotographic photosensitive member or an electrostatic recording derivative with a developer, and forming a toner on the electrostatic latent image carrier. Simultaneous development process for collecting toner remaining on the latent electrostatic image bearing member after transfer, and transfer for transferring the toner image on the latent electrostatic image bearing member to an intermediate transfer member or a transfer material. The present invention relates to an image forming method including at least a process.

  Conventionally, in an electrophotographic system, an electrostatic charge latent image carrier generally made of a photoconductive substance is charged by various means, and further exposed to form an electrostatic latent image on the surface of the electrostatic latent image carrier. Next, the electrostatic latent image is developed with toner to form a toner image, the toner image is transferred to a transfer material such as paper, and then the toner image is fixed on the transfer material by heat, pressure, and heat and pressure, and a copy is made. Or to obtain a print. At this time, the toner remaining on the photosensitive member without being transferred to the transfer material after transfer (transfer residual toner) is cleaned by various methods, and the above-described steps are repeated.

  In the toner used in such a system, for the purpose of obtaining good developability, cleaning property, transferability by adjusting the chargeability stability, durability stability, environmental stability, and fluidity of the toner, there are various types. It is generally known to add inorganic fine particles and the like. In addition, there is an urgent need to develop a color toner that exhibits a stable charge amount even under a wide range of environments because of the influence of temperature and humidity on the charge amount of the toner.

  In order to obtain good characteristics as described above, it is effective to externally add fine particles having various compositions and particle sizes to the surface of the toner base. For example, inorganic fine particles having a small primary particle diameter are used for the purpose of imparting fluidity to the toner and stabilizing charging.

  However, the toner to which such inorganic fine particles are externally added is, for example, stress with a carrier when used as a two-component developer, developer coating blade when used as a one-component developer, developer supply It is subjected to stress from the roller, the inner wall of the developing device, the stirring blade, the collision between toners, or the like. As a result, the inorganic fine particles adhering to the toner base surface are embedded, and it has been confirmed that the desired effect is lowered.

  In order to reduce the burying of the inorganic fine particles, for example, a method of using large-diameter inorganic particles in combination is effective (for example, see Patent Documents 1 to 5).

  The addition of large-diameter inorganic particles produces a so-called spacer effect, and the surface of the toner to which the inorganic fine powder is adhered is the surface of the carrier, the developer coating blade, the developer supply roller, the inner wall of the developing device, the stirring blade, other toners, etc. Prevent direct contact and reduce stress. As a result, the lifetime of the inorganic fine powder can be extended by suppressing the embedding of the inorganic fine powder on the surface of the toner base.

  Further, as the cleaning method, an elastic rubber blade is pressed on the electrostatic latent image bearing member to mechanically remove the transfer residual toner, or a brush roller in which fine fibers are planted is rotated at high speed, There is known a brush cleaning method or the like in which toner is attached to the hair ends to remove transfer residual toner.

  In the case of an image forming method using such a cleaning method, it is necessary to provide a unit for cleaning, and work for collecting waste toner after cleaning occurs, or usable transfer residual toner is collected. Therefore, there is a problem that the printing cost per page increases. In addition, since the cleaning member is in direct contact with the electrostatic latent image carrier, depending on the durability over a long period of time, scratches and abrasion may occur on the photosensitive member, and the surface of the electrostatic latent image carrier may be deteriorated. As a result, a good image may not be obtained over a long period of time, such as a streak image due to scratches or a decrease in image density due to wear.

  Therefore, in recent years, the entire image forming apparatus has been made compact and ecologically compatible by eliminating waste toner. In order to reduce the amount of toner consumed per page, the transfer residual toner is collected and reused without using the cleaning method described above. Cleanerless systems have been widely proposed (Patent Document 6 and Patent Document 7). Among them, copiers and printers employing a so-called simultaneous development cleaning system that collects transfer residual toner in a developing device simultaneously with development have been put into practical use. In particular, since this simultaneous development cleaning system does not use a cleaning unit, dramatic progress can be seen with respect to ecology by making the apparatus compact and eliminating waste toner.

  However, when such a simultaneous development cleaning method is used, problems such as suppression and removal of deposits on the surface of the latent electrostatic image bearing member remain.

  In particular, when it is repeated many times in a high humidity environment, ozone generated in the charging step for charging the electrostatic charge latent image carrier reacts with nitrogen in the air to form nitrogen oxides (NOx), and these nitrogen oxides Reacts with moisture in the air to form nitric acid and adheres to the surface of the latent electrostatic image bearing member, thereby reducing the resistance of the surface of the latent electrostatic image bearing member. For this reason, an image flow occurs in the electrostatic latent image bearing member during image formation. There is known a method for improving the image flow by adding particles having an abrasive action to the toner and peeling off the charged product adhering to the surface of the electrostatic latent image bearing member.

  For example, Patent Document 8 and Patent Document 9 propose a method of adding strontium titanate powder to toner particles. The strontium titanate powder used in these methods has an excellent polishing effect because it has a small particle size and few coarse particles. However, the strontium titanate powder used in these methods is effective in preventing filming and fusing by the toner on the electrostatic latent image bearing member, but it eliminates charged products. There is still room for improvement.

  Patent Document 10 proposes a method of using toner particles containing an abrasive substance and a fatty acid metal salt. Patent Document 11 proposes a method of externally adding a fatty acid metal salt and a titanic acid compound to toner particles. Patent Document 12 proposes a method of externally adding a metal oxide surface-treated with a lubricant such as a fatty acid metal salt.

  However, none of these methods is sufficient for removing the charged product. Further, in the case of long-term use, the metal oxide fine particles used together for improving fluidity and charging stability are embedded in the toner base, and there is still room for improvement from the viewpoint of durability.

JP-A-4-204751 JP-A-5-346682 JP-A-6-313980 JP-A-6-332235 JP-A-7-92724 JP-A-5-054822 JP-A-10-307456 Japanese Patent Laid-Open No. 10-10770 Japanese Patent No. 3047900 JP 2000-162812 A JP-A-8-272132 JP 2001-296688 A

An object of the present invention is to provide a toner that solves the above problems. That is, in order to obtain a high-quality image,
1) No deterioration in developability (increased fog) or decrease in transfer efficiency even during long-term use.
2) Excellent in suppressing or preventing the occurrence of image flow during image formation even in a high humidity environment.
Another object of the present invention is to provide a toner and an image forming method capable of simultaneously achieving the above.

  The present invention relates to a toner containing colored particles containing at least a binder resin and a colorant and an external additive, wherein the external additive has at least an average primary particle size Da of 80 to 300 nm and is non-crystalline. In particular, the present invention relates to a toner characterized by containing two types of inorganic fine particles (A) and an average primary particle diameter Db of 80 to 300 nm and crystalline inorganic fine particles (B).

The present invention also provides a charging step of charging the electrostatic latent image carrier, an electrostatic latent image forming step of forming an electrostatic latent image on the charged electrostatic latent image carrier, and developing the electrostatic latent image. Development with an agent to form a toner image on the electrostatic latent image carrier, and at the same time, a development simultaneous recovery step of collecting the toner remaining on the electrostatic latent image carrier after transfer, and the electrostatic latent image carrier In an image forming method having at least a transfer step of transferring the toner image on the intermediate transfer member or transfer material,
The toner relates to an image forming method, wherein the toner is configured as described above.

  By using the above-mentioned at least two kinds of mixed fine particles as external additives, there is no deterioration in developability and change in transferability, and further excellent polishing effect and removal of charged products can be performed in a high humidity environment. Thus, a toner capable of preventing the image flow is obtained.

  Further, by using the toner of the present invention, a charging step for charging the electrostatic latent image carrier, an electrostatic latent image forming step for forming an electrostatic latent image on the charged electrostatic latent image carrier, and the static The electrostatic latent image is developed with a developer to form a toner image on the electrostatic latent image carrier, and at the same time, a development simultaneous recovery step of recovering the toner remaining on the electrostatic latent image carrier after transfer, Even in an image forming method having at least a transfer step of transferring a toner image on an electrostatic latent image carrier to an intermediate transfer member or a transfer material, a good image can be obtained over a long period of time.

  In the present invention, a toner containing at least a colored resin containing a binder resin and a colorant and an external additive, wherein the external additive has at least an average primary particle size Da of 80 to 300 nm and is amorphous. By using a toner characterized by containing two types of inorganic fine particles (A) and an average primary particle diameter Db of 80 to 300 nm and containing two types of crystalline inorganic fine particles (B) The reason why the charged product on the surface of the latent electrostatic image bearing member (photosensitive member) causing the image flow can be removed at the same time as the deterioration of the property can be prevented is as follows.

  In the development and transfer processes, the two forces of “electrostatic attraction of electric field” and “adhesion force with toner particle carrier” dominate the toner behavior. In order to prevent deterioration of developability and transferability, development / transferability is improved by making the relationship between these two forces “electrostatic attractive force of electric field”> “adhesive force with toner particle carrier”. Is. In order to increase the “electrostatic attraction of electric field”, for example, it can be controlled by increasing the developing bias and the transfer current, ie, the force to peel off toner particles from the carrier or electrostatic latent image bearing member by electrostatic force. Such problems are likely to occur. Therefore, it is preferable to weaken the “adhesion force with the toner particle carrier”, that is, to reduce the adhesion force between the carrier or electrostatic latent image carrier and the toner particles.

  In order to reduce this adhesion, it is effective to reduce the contact area between the toners, between the toner / carrier, and further with the electrostatic latent image carrier by the so-called spacer effect by adding inorganic particles having a large particle diameter. Means.

  On the other hand, when particles having an abrasive effect (hereinafter referred to as abrasives) are added to the toner for the purpose of removing the chargeable organisms on the surface of the latent electrostatic image bearing member, the surface of the latent electrostatic image bearing member (photoreceptor) The reason why the toner filming and fusing can be prevented is as follows. The toner remaining on the electrostatic latent image bearing member after the transfer step of the image forming process comes into contact with a member that contacts the electrostatic latent image bearing member, and a part of the toner and a part of the abrasive released from the toner base. Remains in the vicinity of the contact member. At this time, the contact member rubs the surface of the electrostatic latent image bearing member together with the toner and the abrasive with a pressure that contacts the electrostatic latent image bearing member. Further, when filming or fusing with toner occurs on the surface of the latent electrostatic image bearing member, the surface is adhered in a convex shape with a size of several hundred nm to several tens of μm. In that case, when the toner passes through the contact member, the abrasive acts with a larger pressure. Thus, the polishing effect can be efficiently obtained by the filming and fusion part.

  However, an ionic substance such as nitrate ion, which is a charged product, adheres extremely thinly to the surface of the electrostatic charge latent image carrier. In order to remove the ionic substance efficiently, for example, it is conceivable to increase the contact pressure of the contact member. In this case, the electrostatic charge latent image carrier is shaved and the electrostatic charge latent image is carried. This is not preferable because the life of the body is shortened. Therefore, in order to remove the charged product adhering to the surface of the latent electrostatic image bearing member without increasing the contact pressure of the contact member, it is necessary to increase the polishing ability of the abrasive itself.

  Conventional general abrasives have a particle size as large as μm and the above polishing effect is too strong, so that the electrostatic charge latent image carrier is likely to be scratched, and the particle shape is spherical or nearly spherical. It is presumed that it was insufficient for removing the charged product due to the small contact area with the surface of the latent electrostatic image bearing member, the slippage from the contact member, and the difficulty of staying in the vicinity of the contact member. The

  Therefore, as a result of intensive studies by the present inventors, the average primary particle size Da is 80 to 300 nm as a large particle inorganic particle that exhibits a spacer effect, and is added to the toner in a non-crystalline inorganic fine particle (A). The average primary particle diameter Db is 80 to 300 nm as an abrasive to be used, and by using the crystalline inorganic fine particles (B) in combination, deterioration of developability and transferability can be prevented, and at the same time, it causes image flow. It has been found that the charged product on the surface of the electrostatic latent image bearing member can be efficiently removed. What is particularly important is that the inorganic fine particles (A) aiming at the spacer effect are non-crystalline and the inorganic fine particles (B) aiming at the polishing effect are crystalline.

  In general, large-sized inorganic particles used as spacers are spherical to nearly spherical, have a small contact area with the toner base, move to the surface of the toner base after long-term use, and are localized to a site where friction is expected to be large. Easy to exist. Therefore, in order for the inorganic fine particles (A) to sufficiently exhibit the spacer effect and maintain stable transferability, the toner adheres uniformly to the surface of the toner base and does not become localized even after long-term use. It is necessary to continue to adhere uniformly on the surface of the mother body.

  In general, non-crystalline particles tend to have a lower dielectric constant than crystalline particles. Therefore, in the inorganic fine particles (A) used in the toner of the present invention, the charge accumulation of the particles themselves is appropriately maintained, and aggregation of the inorganic fine particles (A) is suppressed.

  Furthermore, non-crystalline particles do not form a fine crystal form in the chemical structure and have a high porosity, and therefore have a lower specific gravity than that of crystalline. Whereas the specific gravity of the crystalline particles obtained through a general firing process is 4.0 or more, for example, a sol-gel body is produced by the alkoxide method, and is synthesized by slowly drying under low temperature conditions. In the case of particles, the specific gravity is 2.0 or less.

  In general, the specific gravity of the toner base particles is 1.3 or less for a non-magnetic toner, and 2.0 or less for a magnetic toner containing a magnetic material. It was also found that the amorphous inorganic fine particles (A) have a small specific gravity difference from the toner base particles even if they are large-sized fine particles, and thus are less liberated from the toner base.

  From the above, it can exist uniformly over the entire toner base surface over a long period of time, and the spacer effect can be maintained.

  Further, the low dielectric constant of the inorganic fine particles (A) added to the toner can suppress an excessive change in chargeability particularly in a low-temperature and low-humidity environment, which is preferable from the viewpoint of durability stability.

  On the other hand, since the inorganic fine particles (B) aiming at the polishing effect are crystalline, the particles are harder and more effective in polishing than the non-crystalline case, and the specific gravity is high. It tends to be low. As described above, the abrasive is partially released from the toner base and exists alone, so that the polishing effect is maximized.

  However, if the abrasive is liberated excessively, the abrasive itself is generally difficult to transfer and accumulates in the toner and developer and in the vicinity of the contact member to the electrostatic latent image bearing member. It becomes a cause of scratches on the body. Therefore, it is necessary to appropriately adjust the amount of the abrasive that is liberated.

  In the case of the toner of the present invention, non-crystalline inorganic fine particles (A) that easily adhere to the surface of the toner base, even if the particles are large in size, are adhering to the surface of the toner base. The inorganic fine particles (B) having the same particle size can enter into the gaps with a uniform spacing. As a result, even when the toner comes into contact with the carrier or other toner, the inorganic fine particles (A) serve as spacers, the force applied to the inorganic fine particles (B) is reduced, and excessive release of the inorganic fine particles (B) is suppressed. It seems that this is possible. Further, it was confirmed that the presence of the inorganic fine particles (B) can prevent the inorganic fine particles (A) from being localized on the surface of the toner base, and the spacer effect is further maintained even in long-term use.

  As described above, by using the inorganic fine particles (A) and (B) of the present invention in combination, it is possible to allow the inorganic fine particles to be present on the toner base surface in a well-balanced manner even when the particle size is large. . That is, even with a plurality of large particle diameter particles having different effects, the synergistic effect obtained for the first time by using the specific inorganic fine particles in combination not only maximizes the addition effect of each inorganic fine particle, but also long-term Even in the use of the toner, it is possible to obtain a toner which does not cause deterioration in developability and transfer efficiency and can prevent the occurrence of image flow during image formation even in a high humidity environment.

  In the present invention, “non-crystalline” means a peak having a measured intensity of 10000 cps (count per second) or more and a half-value half-width of 0.3 degrees or less as shown in FIG. This is a state that does not exist, and is clearly different from the “crystalline” diffraction pattern (FIG. 2). In general, in X-ray diffraction measurement, a crystalline substance shows a specific diffraction peak depending on the crystal plane spacing depending on Bragg's diffraction conditions, and the diffraction intensity depends on the crystal state and crystallinity. The measurement intensity of the line diffraction is 10,000 cps or more and the half width at half maximum is 0.3 degrees or less. That is, a substance having no peak as described above can be considered as an amorphous substance. In the actual measurement, the influence of the direct beam is large in the range where the measurement angle 2θ is less than 6 degrees, and the measurement intensity decreases as the measurement angle 2θ increases. Therefore, in the range where 2θ exceeds 40 degrees, the measurement intensity is small. In the range, it is not preferable to make a crystal or non-crystal judgment.

  The “half width at half maximum” means a width that is ½ of the peak width (full width at half maximum) at ½ measurement intensity of the peak top measurement intensity (cps).

For the measurement of the X-ray diffraction of the present invention, for example, an X-ray diffractometer RINT-TTR II manufactured by Rigaku Corporation is used, and measurement is performed under the following conditions using CuKα rays.
X-ray tube: Cu
Tube voltage: 50 kV
Tube current: 300 mA
Scan method: 2θ / θ scan scan speed: 2 deg. / Min
Sampling interval: 0.02 deg.
Divergence slit: 0.50 deg.
Scattering slit: 0.50 deg.
Light receiving slit: 0.3 mm

The measurement sample is placed on a glass plate so as to be about 12 mg / cm ^2, and the measurement is performed after the surface has no irregularities.

  Further, in the present invention, the relationship between the free rate (volume%) Sa and Sb of the inorganic fine particles (A) and (B) with respect to the toner base particles is 0.1 <Sa ≦ 20 and 20 <Sb ≦ 50. It is more preferable that 0.1 <Sa ≦ 10 and 20 <Sb ≦ 45.

  Here, the liberation rate is obtained by calculating the volume percentage of inorganic fine particles liberated from toner base particles, and is measured by a particle analyzer (PT1000: manufactured by Yokogawa Electric Corporation). In the present invention, the inorganic fine particles (A) and (B) are released from the toner base particles at a rate of 0.1 <Sa ≦ 20 and 20 <Sb ≦ 50. Inorganic fine particles (A) for preventing deterioration of developability and transferability, and inorganic fine particles (B) for removing charged products on the surface of the electrostatic latent image bearing member by being partially released, Will work more efficiently.

  Furthermore, in the present invention, the relationship between the average primary particle diameters Da and Db of the inorganic fine particles (A) and (B) is preferably 0.8 Da ≦ Db ≦ 1.5 Da, and 0.8 Da ≦ Db ≦ 1. More preferably, it is 3 Da. When Db is less than 0.8 Da, the inorganic fine particles (B) enter the gaps between the inorganic fine particles (A), and are less liberated from the toner base surface. There is a risk that the polishing effect of the particles will be insufficient. On the other hand, when Db exceeds 1.3 Da, it is difficult for the inorganic fine particles (B) to enter the gaps between the inorganic fine particles (A), the release from the toner base surface increases, and the polishing effect is too strong. There is a risk that the image carrier (photoconductor) may be scratched.

  In the present invention, the inorganic fine particles (A) are non-crystalline inorganic fine particles having an average primary particle size Da of 80 to 300 nm, more preferably 80 to 200 nm, and still more preferably 90 to 150 nm. When Da is less than 80 nm, the function as a spacer is weak, and the contribution to improving transferability is small. On the other hand, when Da exceeds 300 nm, it becomes easier to detach from the toner, making it difficult to stably adhere to the toner base surface, and transfer efficiency is lowered. In addition, the toner is detached from the toner during development and contaminates the surroundings of the developing device, or the detached fine powder adheres to the photosensitive drum, the carrier, and the like, resulting in deterioration of charging performance.

  In the present invention, the inorganic fine particles (A) are not particularly limited as long as they are non-crystalline inorganic fine particles having an average primary particle size Da of 80 to 300 nm. It may be a composite composition of more than one species. As the production method, for example, a method produced by a conventionally known technique obtained by any method such as a gas phase decomposition method, a combustion method, or a deflagration method can be used.

  In the present invention, in particular, a known sol-gel method in which a solvent is removed from a silica sol suspension obtained by hydrolyzing and condensing a alkoxysilane with a catalyst in an organic solvent in which water is present, and dried to form particles. It is particularly preferable to use fine particles produced by the above method. The silica particles produced by the sol-gel method preferably have a sharp particle size distribution, and spherical particles can be obtained, and particles having a desired particle size distribution can be obtained by changing the reaction time. Further, the sol-gel silica surface may be used after being hydrophobized. As the hydrophobizing agent, a silane compound is preferably used, and monochlorosilane such as hexamethyldisilazane, trimethylchlorosilane, triethylchlorosilane, trimethylmethoxysilane, trimethyl. Examples thereof include monoalkoxysilanes such as ethoxysilane, monoaminosilanes such as trimethylsilyldimethylamine and trimethylsilyldiethylamine, and monoacyloxysilanes such as trimethylacetoxysilane.

  Moreover, as a method for obtaining amorphous titanium oxide, for example, a method of thermally decomposing volatile titanium oxide in a gas phase can be used. In particular, a method of producing a volatile titanium compound such as titanium alkoxide by thermal decomposition at a low temperature of 600 ° C. or lower in the gas phase is suitable. Furthermore, as a preferable production method, a volatile titanium compound is used as a raw material, and the volatile titanium compound is vaporized or atomized at a relatively low temperature of 600 ° C. or less, preferably 250 to 400 ° C., and then decomposed and oxidized. The titanium fine particles are formed, and immediately after the decomposition, they are cooled to a temperature at which the titanium oxide fine particles do not coalesce again, preferably to 100 ° C. or less in the shortest possible time. Further, it is more effective to use a dispersion aid, a surface modifier or the like for the purpose of preventing coalescence of titanium oxide fine particles during cooling or after cooling, or for the purpose of improving collection and recovery.

  Examples of the volatile titanium compound used in the present invention include titanium tetramethoxide, titanium tetraethoxide, titanium tetrapropoxide, titanium tetrabutoxide, and diethoxytitanium oxide, as well as titanium tetrachloride and titanium tetrabromide. Further, titanium compounds having volatility such as tetrahalogenated titanium such as trihalogenated monoalkoxytitanium, dihalogenated dialkoxytitanium, and monohalogenated trialkoxytitanium can be used.

  In addition, when vaporizing or atomizing a volatile titanium compound, it is preferable to dilute a volatile titanium compound to 0.1-10 volume% with a dilution gas. This dilution gas serves as a carrier gas for introducing the vaporized volatile titanium compound into a decomposition furnace for performing decomposition. As the dilution gas used here, an inert gas such as argon, helium or nitrogen, water vapor, oxygen or the like is used, and it is particularly preferable to use helium or nitrogen gas. Further, as described above, a dispersion aid, a surface modifier, and the like may be included as necessary.

  In the method for producing titanium oxide used in the present invention as described above, an oxygen-containing compound such as alkoxide is used in order to decompose titanium oxide fine particles after vaporizing or atomizing the volatile titanium compound. In other cases, an oxygen-containing gas is required. Moreover, as temperature which decomposes | disassembles a volatile titanium compound, 600 degrees C or less is preferable, and it is preferable to decompose especially at 250-350 degreeC. When the temperature is lower than this, a sufficient decomposition rate cannot be obtained. On the other hand, when the decomposition temperature is high, it becomes difficult to obtain fine particles. In order to adjust the charging characteristics of the obtained titanium oxide fine particles and to improve the stability under high humidity, it is possible to perform surface treatment within a range that does not impair the characteristics of titanium oxide, such as hydrophobization. There is no restriction on the method of hydrophobizing, but in the present invention, when rapidly cooling, for example, the titanium oxide fine particles after thermal decomposition are treated together with an inert gas refrigerant such as nitrogen gas. The method of hydrophobizing is the most effective.

  In the toner of the present invention, the amount of the inorganic fine particles (A) added is 0.3 to 5.0 parts by mass, more preferably 0.5 to 3.0 parts by mass with respect to 100 parts by mass of the toner base particles. .

  In the present invention, the inorganic fine particles (B) are crystalline inorganic fine particles having an average primary particle diameter Db of 80 to 300 nm, more preferably 80 to 200 nm. If Db is less than 80 nm, the effect of polishing the particles in the cleaner portion is insufficient. On the other hand, if Db exceeds 300 nm, the above-described polishing effect is too strong, and the electrostatic charge latent image carrier (photoconductor) is damaged. Not suitable.

  In the present invention, the inorganic fine particles (B) may be strontium titanate, barium titanate, calcium titanate, cerium oxide, silicon carbide, as long as they are crystalline inorganic fine particles having an average primary particle diameter Db of 80 to 300 nm. The composition of titania, alumina, etc. is not particularly limited, but strontium titanate is preferred in the present invention.

  Furthermore, in the present invention, by using inorganic fine particles of perovskite type crystals whose inorganic fine particles (B) are approximately cubic and / or rectangular parallelepiped, the charged products adhering to the surface of the latent electrostatic image bearing member can be removed. I found that I could do it more efficiently. Since the particle shape of the abrasive is approximately cubic and / or cuboid, the contact area between the abrasive and the surface of the latent electrostatic image bearing member can be increased, and the ridge line of the cube and / or cuboid of the abrasive Since the toner comes into contact with the surface of the latent electrostatic image bearing member, good scraping property of the toner can be obtained.

  About the average particle diameter of the inorganic fine particle of the perovskite type crystal | crystallization in this invention, 100 particle diameters were measured from the photograph image | photographed with the magnification of 50,000 times with the electron microscope, and the average was calculated | required. The particle size was determined as (a + b) / 2, where a is the longest side of the primary particles and b is the shortest side. Further, the charged product can be more efficiently removed by setting the content of particles having a substantially cubic and / or rectangular parallelepiped shape in the perovskite crystal inorganic fine particles used in the present invention to 50% by number or more. Therefore, it is preferable.

  In the toner of the present invention, the addition amount of the inorganic fine particles (B) is 0.1 to 5.0 parts by mass, more preferably 0.1 to 3.0 parts by mass with respect to 100 parts by mass of the toner base particles. If the addition amount is less than 0.1 parts by mass, the effect of removing the deposits on the photoreceptor is insufficient, and if it is more than 5 parts by mass, the effect on the chargeability of the toner is increased, which is not preferable.

  The inorganic fine particles (B) used in the present invention may be surface-treated with a known surface treatment agent. In the present invention, the surface treatment with a fatty acid having 8 to 35 carbon atoms or a metal salt of a fatty acid having 8 to 35 carbon atoms can be preferably used because it can improve the adhesion of the toner to the electrophotographic member including the photoreceptor. It is done. The number of carbon atoms of the fatty acid or the metal salt thereof for treating the surface of the inorganic fine particles (B) is more preferably 10-30. When the number of carbon atoms exceeds 35, the adhesion between the surface of the inorganic fine particles and the fatty acid or metal salt thereof is lowered, and the long-term use peels off the surface of the inorganic fine particles, resulting in a decrease in durability. Salt may cause image defects. If the number of carbon atoms of the fatty acid or fatty acid metal salt is less than 8, the effect of preventing the adhesion of toner to the electrophotographic member containing the photoreceptor may not be sufficiently obtained.

  The preferable processing amount of the fatty acid or the metal salt thereof with respect to the inorganic fine particles is 0.1 to 15.0 parts by mass, more preferably 0.5 to 12.0 parts by mass with respect to 100 parts by mass of the inorganic fine particle matrix.

  The method for producing the inorganic fine particles (B) used in the present invention is not particularly limited, and those produced by a conventionally known technique can be used. For example, the inorganic fine particles of perovskite crystals are obtained by adding strontium hydroxide to a titania sol dispersion obtained by adjusting the pH of a hydrous titanium oxide slurry obtained by hydrolyzing a titanyl sulfate aqueous solution, It can be synthesized by heating up to. By setting the pH of the hydrous titanium oxide slurry to 0.5 to 1.0, a titania sol having good crystallinity and particle size can be obtained.

  For the purpose of removing ions adsorbed on the titania sol particles, an alkaline substance such as sodium hydroxide is preferably added to the dispersion of the titania sol. At this time, it is preferable that the pH of the slurry is not 7 or higher so that sodium ions and the like are not adsorbed on the surface of the hydrous titanium oxide. The reaction temperature is preferably 60 ° C. to 100 ° C., and in order to obtain a desired particle size distribution, the temperature rising rate is preferably 30 ° C./hour or less, and the reaction time is preferably 3 to 7 hours.

Examples of the method for subjecting the inorganic fine particles produced by the above method to surface treatment with a fatty acid or a metal salt thereof include the following methods. For example, in an Ar gas or N ₂ gas atmosphere, the inorganic fine particle slurry can be placed in a fatty acid sodium aqueous solution to precipitate the fatty acid on the perovskite crystal surface. Also, for example, in an Ar gas or N ₂ gas atmosphere, the inorganic fine particle slurry is placed in a fatty acid sodium aqueous solution, and the desired metal salt aqueous solution is dropped while stirring to precipitate and adsorb the fatty acid metal salt on the perovskite crystal surface. Can be made. For example, if a sodium stearate aqueous solution and aluminum sulfate are used, aluminum stearate can be adsorbed.

In addition, in order to prevent a decrease in charge amount of the toner in the development process due to moisture absorption of the inorganic fine particles in a high humidity environment, the BET specific surface area of the inorganic fine particles (A) and (B) used in the present invention is 5 to 40 m ^2. / G is preferable. By setting the specific surface area to 5 to 40 m ² / g, the absolute amount of water adsorbed on the surface of the inorganic fine particles can be kept small, so that the influence on the frictional charging of the toner can be reduced. The specific surface area is measured according to the BET method by using a specific surface area measuring device Autosorb 1 (manufactured by Yuasa Ionics) to adsorb nitrogen gas on the sample surface and using the BET multipoint method.

  Further, in addition to the inorganic fine particles (A) and (B), inorganic or organic fine particles may be externally added to the toner particles of the present invention as fluidity imparting / charging control / abrasive / cleaning aid. it can. Particles used include fluororesin powders such as vinylidene fluoride fine powder and tetrafluoroethylene fine powder, titanium oxide fine powder, alumina fine powder, wet process silica, fine process silica such as dry process silica, and silane Examples thereof include treated silica whose surface is treated with a compound or an organic silicon compound, a titanium coupling agent, silicone oil, or the like.

  In the toner of the present invention, it is preferable to add inorganic fine particles (C) having an average primary particle diameter Dc of 5 to 60 nm for the purpose of controlling the fluidity and chargeability of the toner. The inorganic fine particles (C) may be surface-treated with a silane compound or a coupling agent. If it is smaller than 5 nm, the inorganic fine particles (C) are likely to be embedded in the toner surface due to long-term use, and the physical adhesion of the toner increases, which may impair transferability. On the other hand, if it is larger than 60 nm, the effect of imparting fluidity is reduced, and the charging characteristics tend to become unstable.

  Specific examples of the inorganic fine powder (C) include various metal compounds (aluminum oxide, titanium oxide, strontium titanate, cerium oxide, magnesium oxide, chromium oxide, tin oxide, zinc oxide, etc.) and nitrides (silicon nitride). Etc.), carbides (silicon carbide, etc.), metal salts (calcium sulfate, barium sulfate, calcium carbonate, etc.), fatty acid metal salts (zinc stearate, calcium stearate, etc.), carbon black, silica, etc., preferably hydrophobic Fine titanium oxide particles and / or hydrophobic silica particles. The addition of the hydrophobic titanium oxide fine particles brings about stabilization of the charge, and the addition of the hydrophobic silica fine particles makes it possible to provide a toner having an appropriate charge amount for imparting fluidity and high negative chargeability. The amount of the inorganic fine powder (C) added is 0.1 to 5.0 parts by mass, more preferably 0.1 to 1.5 parts by mass with respect to 100 parts by mass of the toner base particles.

  In the toner of the present invention, the toner base particles (colored particles) are not particularly limited, and contain at least a binder resin having a polyester unit, a colorant, and other components as necessary.

  The binder resin used in the toner of the present invention includes (a) a polyester resin, (b) a hybrid resin having a polyester unit and a vinyl polymer unit, or (c) a hybrid resin and a vinyl polymer. Or (d) a mixture of a polyester resin and a vinyl polymer, and / or (e) a mixture of a hybrid resin and a polyester resin, and (f) a mixture of a polyester unit, a hybrid resin, and a vinyl polymer. It is a resin selected from either.

  In the present invention, “polyester unit” refers to a portion derived from polyester, and “vinyl polymer unit” refers to a portion derived from a vinyl polymer. The polyester monomer constituting the polyester unit is a polyvalent carboxylic acid component and a polyhydric alcohol component, and the vinyl polymer unit is a monomer component having a vinyl group. A monomer having a vinyl group or a monomer having a polyhydric alcohol component and a vinyl group is defined as a “polyester unit” component.

  The binder resin used in the toner of the present invention has a molecular weight distribution measured by gel permeation chromatography (GPC) of the resin component, and has a main peak in a region having a molecular weight of 3500 to 30000, preferably, The molecular weight is in the range of 5000 to 20000, and Mw / Mn is preferably 5.0 or more.

  When the main peak is less than 3500, the high temperature offset resistance of the toner is insufficient. On the other hand, if the main peak exceeds the molecular weight of 30000, sufficient low-temperature fixability cannot be obtained, and application on a high-speed machine becomes difficult. Moreover, when Mw / Mn is less than 5.0, it becomes sharp melt and high gloss is easily obtained, but high-temperature offset resistance cannot be obtained.

  When a polyester resin is used as the binder resin, alcohol and carboxylic acid, carboxylic acid anhydride, carboxylic acid ester, or the like can be used as a raw material monomer. Specifically, for example, as the dihydric alcohol component, polyoxypropylene (2.2) -2,2-bis (4-hydroxyphenyl) propane, polyoxypropylene (3.3) -2,2-bis ( 4-hydroxyphenyl) propane, polyoxyethylene (2.0) -2,2-bis (4-hydroxyphenyl) propane, polyoxypropylene (2.0) -polyoxyethylene (2.0) -2,2 -Alkylene oxide adducts of bisphenol A such as bis (4-hydroxyphenyl) propane, polyoxypropylene (6) -2,2-bis (4-hydroxyphenyl) propane, ethylene glycol, diethylene glycol, triethylene glycol, 1, 2-propylene glycol, 1,3-propylene glycol, 1,4-butanediol, Opentyl glycol, 1,4-butenediol, 1,5-pentanediol, 1,6-hexanediol, 1,4-cyclohexanedimethanol, dipropylene glycol, polyethylene glycol, polypropylene glycol, polytetramethylene glycol, bisphenol A And hydrogenated bisphenol A.

  Examples of the trivalent or higher alcohol component include sorbitol, 1,2,3,6-hexanetetrol, 1,4-sorbitan, pentaerythritol, dipentaerythritol, tripentaerythritol, 1,2,4-butanetriol, 1,2,5-pentanetriol, glycerol, 2-methylpropanetriol, 2-methyl-1,2,4-butanetriol, trimethylolethane, trimethylolpropane, 1,3,5-trihydroxymethylbenzene, etc. Can be mentioned.

  Examples of the acid component include aromatic dicarboxylic acids such as phthalic acid, isophthalic acid and terephthalic acid or anhydrides thereof; alkyl dicarboxylic acids such as oxalic acid, adipic acid, sebacic acid and azelaic acid or anhydrides thereof; Succinic acid substituted with an alkyl group or an anhydride thereof; unsaturated dicarboxylic acids such as fumaric acid, maleic acid and citraconic acid or anhydrides thereof;

  Among these, in particular, a bisphenol derivative represented by the following general formula (1) is used as a diol component, and a carboxylic acid component (for example, fumaric acid) composed of a divalent or higher carboxylic acid or an acid anhydride thereof or a lower alkyl ester thereof. A polyester resin obtained by polycondensation using acid, maleic acid, maleic anhydride, phthalic acid, terephthalic acid, trimellitic acid, pyromellitic acid, etc.) as an acid component is preferable because it has good charging characteristics as a color toner. .

〔式中、Ｒはエチレン、プロピレン基であり、ｘ，ｙはそれぞれ１以上の整数であり、かつｘ＋ｙの平均値は２〜１０である。〕

[Wherein, R is an ethylene or propylene group, x and y are each an integer of 1 or more, and the average value of x + y is 2 to 10. ]

  Examples of the trivalent or higher polyvalent carboxylic acid component for forming the non-linear polyester resin include 1,2,4-benzenetricarboxylic acid, 1,2,5-benzenetricarboxylic acid, 1,2,4, and the like. -Naphthalene tricarboxylic acid, 2,5,7-naphthalene tricarboxylic acid, 1,2,4,5-benzenetetracarboxylic acid, and anhydrides and ester compounds thereof. The amount of the trivalent or higher polyvalent carboxylic acid component is preferably 0.1 to 1.9 mol% based on the total monomer.

  Further, when a hybrid resin having a polyester unit and a vinyl polymer unit is used as the binder resin, further improved release agent dispersibility, low-temperature fixability, and offset resistance can be expected. The “hybrid resin component” used in the present invention means a resin in which a vinyl polymer unit and a polyester unit are chemically bonded. Specifically, a polyester unit and a vinyl polymer unit obtained by polymerizing a monomer having a carboxylic acid ester group such as (meth) acrylic acid ester are formed by a transesterification reaction, preferably a vinyl polymer. Is used to form a graft copolymer (or block copolymer) having a backbone polymer and a polyester unit as a branch polymer.

  The following are mentioned as a vinyl-type monomer for producing | generating a vinyl-type polymer. Styrene; o-methylstyrene, m-methylstyrene, p-methylstyrene, α-methylstyrene, p-phenylstyrene, p-ethylstyrene, 2,4-dimethylstyrene, pn-butylstyrene, p-tert- Butyl styrene, pn-hexyl styrene, pn-octyl styrene, pn-nonyl styrene, pn-decyl styrene, pn-dodecyl styrene, p-methoxy styrene, p-chloro styrene, 3, Styrene and derivatives thereof such as 4-dichlorostyrene, m-nitrostyrene, o-nitrostyrene, p-nitrostyrene; styrene unsaturated monoolefins such as ethylene, propylene, butylene and isobutylene; unsaturated such as butadiene and isoprene Polyenes; vinyl chloride, vinyl chloride, vinyl bromide, fluoride Vinyl halides such as vinyl; vinyl esters such as vinyl acetate, vinyl propionate and vinyl benzoate; methyl methacrylate, ethyl methacrylate, propyl methacrylate, n-butyl methacrylate, isobutyl methacrylate, n-methacrylate Α-methylene aliphatic monocarboxylic acid esters such as octyl, dodecyl methacrylate, 2-ethylhexyl methacrylate, stearyl methacrylate, phenyl methacrylate, dimethylaminoethyl methacrylate, diethylaminoethyl methacrylate; methyl acrylate, ethyl acrylate Propyl acrylate, n-butyl acrylate, isobutyl acrylate, n-octyl acrylate, dodecyl acrylate, 2-ethylhexyl acrylate, stearyl acrylate, 2-acrylate Acrylic esters such as lorethyl and phenyl acrylate; vinyl ethers such as vinyl methyl ether, vinyl ethyl ether and vinyl isobutyl ether; vinyl ketones such as vinyl methyl ketone, vinyl hexyl ketone and methyl isopropenyl ketone; N-vinyl pyrrole; N-vinyl compounds such as N-vinyl carbazole, N-vinyl indole and N-vinyl pyrrolidone; vinyl naphthalenes; acrylic acid or methacrylic acid derivatives such as acrylonitrile, methacrylonitrile and acrylamide.

  In addition, unsaturated dibasic acids such as maleic acid, citraconic acid, itaconic acid, alkenyl succinic acid, fumaric acid, mesaconic acid; maleic anhydride, citraconic anhydride, itaconic anhydride, alkenyl succinic anhydride, etc. Unsaturated dibasic acid anhydride; maleic acid methyl half ester, maleic acid ethyl half ester, maleic acid butyl half ester, citraconic acid methyl half ester, citraconic acid ethyl half ester, citraconic acid butyl half ester, itaconic acid methyl half ester, Alkenyl succinic acid half ester, fumaric acid methyl half ester, mesaconic acid methyl half ester unsaturated dibasic acid half ester; dimethylmaleic acid, dimethyl fumaric acid unsaturated dibasic acid ester; acrylic acid, meta Α, β-unsaturated acids such as rillic acid, crotonic acid and cinnamic acid; α, β-unsaturated acid anhydrides such as crotonic acid anhydride and cinnamic acid anhydride, the α, β-unsaturated acid and lower fatty acids And monomers having a carboxyl group such as alkenylmalonic acid, alkenylglutaric acid, alkenyladipic acid, acid anhydrides and monoesters thereof.

  Further, acrylic acid or methacrylic acid esters such as 2-hydroxyethyl acrylate, 2-hydroxyethyl methacrylate, 2-hydroxypropyl methacrylate; 4- (1-hydroxy-1-methylbutyl) styrene, 4- (1-hydroxy-1) -Methylhexyl) Monomers having a hydroxy group such as styrene.

  In the toner of the present invention, the vinyl polymer unit of the binder resin may have a crosslinked structure crosslinked with a crosslinking agent having two or more vinyl groups. In this case, the crosslinking agent used is Examples of aromatic divinyl compounds include divinylbenzene and divinylnaphthalene; examples of diacrylate compounds linked by an alkyl chain include ethylene glycol diacrylate, 1,3-butylene glycol diacrylate, and 1,4-butanediol di Examples include acrylate, 1,5-pentanediol diacrylate, 1,6 hexanediol diacrylate, neopentyl glycol diacrylate, and the above compounds in which acrylate is replaced by methacrylate; linked by an alkyl chain containing an ether bond. As diacrylate compounds For example, diethylene glycol diacrylate, triethylene glycol diacrylate, tetraethylene glycol diacrylate, polyethylene glycol # 400 diacrylate, polyethylene glycol # 600 diacrylate, dipropylene glycol diacrylate and those obtained by replacing acrylates of the above compounds with methacrylate Examples of diacrylate compounds linked by a chain containing an aromatic group and an ether bond include polyoxyethylene (2) -2,2-bis (4-hydroxyphenyl) propane diacrylate, polyoxyethylene (4 ) -2,2-bis (4-hydroxyphenyl) propane diacrylate and those obtained by replacing the acrylate of the above compound with methacrylate.

  Polyfunctional cross-linking agents include pentaerythritol triacrylate, trimethylol ethane triacrylate, trimethylol propane triacrylate, tetramethylol methane tetraacrylate, oligoester acrylate, and acrylates of the above compounds replaced with methacrylate; triallylcia Examples include nurate and triallyl trimellitate.

  In the present invention, it is preferable that a monomer component capable of reacting with both resin components is contained in the vinyl polymer component and / or the polyester resin component. Examples of the monomer constituting the polyester resin component that can react with the vinyl polymer include unsaturated dicarboxylic acids such as phthalic acid, maleic acid, citraconic acid, and itaconic acid, or anhydrides thereof. Among the monomers constituting the vinyl polymer component, those capable of reacting with the polyester resin component include those having a carboxyl group or a hydroxy group, and acrylic acid or methacrylic acid esters.

  As a method of obtaining a reaction product of a vinyl polymer and a polyester resin, either a polymer containing a monomer component capable of reacting with each of the vinyl polymer and the polyester resin listed above is present, or either A method obtained by polymerizing both resins is preferred.

  Examples of the polymerization initiator used for producing the vinyl polymer of the present invention include 2,2′-azobisisobutyronitrile and 2,2′-azobis (4-methoxy-2,4-dimethyl). Valeronitrile), 2,2′-azobis (-2,4-dimethylvaleronitrile), 2,2′-azobis (-2methylbutyronitrile), dimethyl-2,2′-azobisisobutyrate, 1 , 1′-azobis (1-cyclohexanecarbonitrile), 2- (carbamoylazo) -isobutyronitrile, 2,2′-azobis (2,4,4-trimethylpentane), 2-phenylazo-2,4-dimethyl -4-methoxyvaleronitrile, 2,2'-azobis (2-methyl-propane), methyl ethyl ketone peroxide, acetylacetone peroxide, cyclo Ketone peroxides such as xanone peroxide, 2,2-bis (t-butylperoxy) butane, t-butyl hydroperoxide, cumene hydroperoxide, 1,1,3,3-tetramethylbutyl hydroper Oxide, di-t-butyl peroxide, t-butylcumyl peroxide, di-cumyl peroxide, α, α'-bis (t-butylperoxyisopropyl) benzene, isobutyl peroxide, octanoyl peroxide, decanoyl Peroxide, lauroyl peroxide, 3,5,5-trimethylhexanoyl peroxide, benzoyl peroxide, m-trioyl peroxide, di-isopropyl peroxydicarbonate, di-2-ethylhexyl peroxydicarbonate Di-n-propyl peroxydicarbonate, di-2-ethoxyethyl peroxycarbonate, di-methoxyisopropyl peroxydicarbonate, di (3-methyl-3-methoxybutyl) peroxycarbonate, acetylcyclohexylsulfonyl peroxide, t-butyl peroxyacetate, t-butyl peroxyisobutyrate, t-butyl peroxyneodecanoate, t-butyl peroxy 2-ethylhexanoate, t-butyl peroxylaurate, t-butyl peroxy Oxybenzoate, t-butyl peroxyisopropyl carbonate, di-t-butyl peroxyisophthalate, t-butyl peroxyallyl carbonate, t-amyl peroxy 2-ethylhexanoate, di-t-butyl peroxyhex Hydro terephthalate, di -t- butyl peroxy azelate and the like.

  Examples of the production method capable of preparing the hybrid resin used in the toner of the present invention include the following production methods (1) to (6).

  (1) A method in which a vinyl polymer, a polyester resin, and a hybrid resin component are blended after production. The blend is produced by dissolving and swelling in an organic solvent (for example, xylene) and then distilling off the organic solvent. The hybrid resin component is synthesized by separately producing a vinyl polymer and a polyester resin, dissolving and swelling in a small amount of an organic solvent, adding an esterification catalyst and an alcohol, and performing a transesterification reaction by heating. The ester compound used can be used.

  (2) A method of producing a polyester unit and a hybrid resin component in the presence of a vinyl polymer unit in the presence of the vinyl polymer unit. The hybrid resin component is produced by a reaction between a vinyl polymer unit (a vinyl monomer can be added if necessary) and a polyester monomer (alcohol, carboxylic acid) and / or polyester. Also in this case, an organic solvent can be appropriately used.

  (3) A method for producing a vinyl polymer unit and a hybrid resin component in the presence of the polyester unit after the production. The hybrid resin component is produced by a reaction between a polyester unit (a polyester monomer can be added if necessary) and a vinyl monomer and / or vinyl polymer unit.

  (4) After the production of the vinyl polymer unit and the polyester unit, the hybrid resin component is produced by adding a vinyl monomer and / or a polyester monomer (alcohol, carboxylic acid) in the presence of these polymer units. Also in this case, an organic solvent can be appropriately used.

  (5) After producing the hybrid resin component, vinyl polymer units and / or polyester units (alcohol, carboxylic acid) are added to carry out addition polymerization and / or polycondensation reaction to produce vinyl polymer units and polyester units. Is done. In this case, as the hybrid resin component, those produced by the production methods (2) to (4) can be used, and those produced by a known production method can be used as necessary. Furthermore, an organic solvent can be used as appropriate.

  (6) A vinyl polymer unit, a polyester unit, and a hybrid resin component are produced by mixing a vinyl monomer and a polyester monomer (alcohol, carboxylic acid, etc.) and continuously performing addition polymerization and condensation polymerization reaction. Furthermore, an organic solvent can be used as appropriate.

  In the production methods (1) to (5), the vinyl polymer unit and / or the polyester unit can use a plurality of polymer units having different molecular weights and crosslinking degrees.

  The binder resin contained in the toner of the present invention may be a mixture of the polyester resin and the hybrid resin.

  As the binder resin contained in the toner of the present invention, a mixture of the polyester resin and vinyl polymer may be used.

  As the binder resin contained in the toner of the present invention, a mixture of the above hybrid resin and vinyl polymer may be used.

  The glass transition temperature of the binder resin contained in the toner of the present invention is preferably 40 to 90 ° C, more preferably 45 to 85 ° C. The acid value of the resin is preferably 1 to 40 mgKOH / g.

  A known pigment or dye can be used as the colorant contained in the toner of the present invention, and is not particularly limited. Examples of the pigment include the following. As a colorant suitable for the magenta color, a pigment or a dye can be used. I. Pigment Red 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 21, 22, 23, 30, 31, 32, 37, 38, 39, 40, 41, 48, 48; 2, 48; 3, 48; 4, 49, 50, 51, 52, 53, 54, 55, 57, 57; 1, 58, 60, 63, 64, 68, 81, 81; 1, 83, 87, 88, 89, 90, 112, 114, 122, 123, 144, 146, 150, 163, 166, 169, 177, 184, 185, 202, 206, 207, 209, 220, 221, 238, 254, etc., C.I. I. Pigment violet 19; C.I. I. Examples of magenta dyes such as Vat Red 1, 2, 10, 13, 15, 23, 29, and 35 include C.I. I. Solvent Red 1, 3, 8, 23, 24, 25, 27, 30, 49, 52, 58, 63, 81, 82, 83, 84, 100, 109, 111, 121, 122, etc. I. Disper thread 9, C.I. I. Solvent Violet 8, 13, 14, 21, 27 etc., C.I. I. Oil-soluble dyes such as disperse violet 1, C.I. I. Basic Red 1, 2, 9, 12, 13, 14, 15, 17, 18, 22, 23, 24, 27, 29, 32, 34, 35, 36, 37, 38, 39, 40, etc. I. Basic violet 1,3,7,10,14,15,21,25,26,27,28, etc. may be mentioned, and such a pigment may be used alone. It is more preferable from the viewpoint of the image quality of a full-color image to improve the sharpness by using in combination, and these are used alone or in combination of two or more.

  As other color pigments, as colorants suitable for cyan, pigments or dyes can be used. I. Pigment Blue 1, 7, 15, 15; 1, 15; 2, 15; 3, 15; 4, 16, 17, 60, 62, 66, etc., C.I. I. Bat Blue 6, C.I. I. Acid Blue 45 and the dye include C.I. I. Solvent Blue 25, 36, 60, 70, 93, 95 etc. are mentioned, These are used alone or in combination of two or more.

  As the colorant suitable for the yellow color, a pigment or a dye can be used. Specifically, examples of the pigment include C.I. I. Pigment Yellow 1, 2, 3, 4, 5, 6, 7, 10, 11, 12, 13, 14, 15, 17, 23, 62, 65, 73, 74, 81, 83, 93, 94, 95, 97, 98, 109, 110, 111, 117, 120, 127, 128, 129, 137, 138, 139, 147, 151, 154, 167, 168, 173, 174, 176, 180, 181, 183, 191, C. I. Vat yellow 1, 3, 20 etc. I. Solvent yellow 19, 44, 77, 79, 81, 82, 93, 98, 103, 104, 112, 162 etc. are mentioned, These are used alone or in combination of two or more.

  As the black colorant, for example, carbon black such as furnace black, channel black, acetylene black, thermal black, and lamp black is used, and iron oxide such as magnetite and ferrite, or yellow / magenta / cyan / black as shown above. The thing adjusted to black using the coloring agent can be utilized.

  In the toner used in the present invention, it is preferable to use a toner obtained by mixing a colorant in advance with the binder resin of the present invention to form a master batch. Then, the colorant can be favorably dispersed in the toner by melt-kneading the colorant master batch and other raw materials (binder resin, wax, etc.).

  When using a resin that can be used in the present invention to masterbatch the colorant, even when a large amount of colorant is used, the dispersibility of the colorant is not deteriorated, and the dispersibility in the toner particles is improved, Excellent color reproducibility such as color mixing and transparency. Further, a toner having a large covering power on the transfer material can be obtained. Further, by improving the dispersibility of the colorant, it is possible to obtain an image with excellent durability stability of toner chargeability and maintaining high image quality.

  The amount of the colorant used is preferably 0.1 to 60 parts by mass, more preferably 0.5 to 50 parts by mass with respect to 100 parts by mass of the binder resin.

  It is preferable to add a release agent to the toner base particles as other components. Next, the release agent that can be used in the present invention will be described. Examples of the release agent that can be used in the present invention include the following. Aliphatic hydrocarbon waxes such as low molecular weight polyethylene, low molecular weight polypropylene, polyolefin copolymers, polyolefin wax, microcrystalline wax, paraffin wax, Fischer-Tropsch wax; oxides of aliphatic hydrocarbon waxes such as oxidized polyethylene wax; Alternatively, block copolymers thereof; waxes mainly composed of fatty acid esters such as carnauba wax, behenyl behenate, and montanic acid ester wax; partially or entirely deoxidized fatty acid esters such as deoxidized carnauba wax. Things. Further, saturated linear fatty acids such as palmitic acid, stearic acid, montanic acid, or long-chain alkyl carboxylic acids having a long-chain alkyl group; unsaturated fatty acids such as brandic acid, eleostearic acid, and valinal acid Saturated alcohols such as stearic alcohol, aralkyl alcohol, behenyl alcohol, carnauvir alcohol, seryl alcohol, melyl alcohol, or long-chain alkyl alcohols having a long-chain alkyl group; polyhydric alcohols such as sorbitol; linol Fatty acid amides such as acid amide, oleic acid amide, lauric acid amide; saturated fatty acids such as methylene bis stearic acid amide, ethylene biscapric acid amide, ethylene bis lauric acid amide, hexamethylene bis stearic acid amide Unsaturated fatty acid amides such as samides, ethylenebisoleic acid amide, hexamethylenebisoleic acid amide, N, N′-dioleyl adipic acid amide, N, N′-dioleyl sebacic acid amide; Aromatic bisamides such as stearamide, N, N'-distearylisophthalamide; fatty acid metal salts such as calcium stearate, calcium laurate, zinc stearate, magnesium stearate (generally referred to as metal soap) Waxes grafted to aliphatic hydrocarbon waxes using vinyl monomers such as styrene and acrylic acid; partially esterified products of fatty acids and polyhydric alcohols such as behenic acid monoglyceride; by hydrogenation of vegetable oils and fats, etc. The resulting hydroxyl group And methyl ester compounds are exemplified.

  The toner of the present invention preferably contains one or more waxes. Furthermore, the toner of the present invention has one or more endothermic peaks in a temperature range of 30 to 200 ° C. in an endothermic curve in differential thermal analysis (DSC) measurement from the viewpoint of achieving both low-temperature fixability and blocking resistance. The peak temperature of the maximum endothermic peak in the endothermic peak is preferably in the range of 60 to 110 ° C. More preferably, the maximum peak of the endothermic curve is in the range of 65 to 100 ° C. When the peak temperature of the maximum endothermic peak is less than 60 ° C., the blocking resistance of the toner may deteriorate, and conversely, when the peak temperature of the maximum endothermic peak exceeds 110 ° C., the fixability is deteriorated.

  The release agent is used in an amount of 0.5 to 10 parts by weight, preferably 2 to 8 parts by weight, per 100 parts by weight of the binder resin.

  If necessary, a charge control agent can be added to the toner base particles as other components. Known charge control agents can be used, and examples thereof include aromatic carboxylic acid derivatives and aromatic carboxylic acid metal compounds. For example, the metal of the aromatic carboxylic acid metal compound is preferably a divalent or higher valent metal atom.

Examples of the divalent metal include Mg ²⁺ , Ca ²⁺ , Sr ²⁺ , Pb ²⁺ , Fe ²⁺ , Co ²⁺ , Ni ²⁺ , Zn ²⁺ and Cu ²⁺ . As such a divalent metal, Zn ²⁺ , Ca ²⁺ , Mg ²⁺ and Sr ²⁺ are preferable. Examples of the trivalent or higher metal include Al ³⁺ , Cr ³⁺ , Fe ³⁺ , Ni ³⁺ , Ti ⁴⁺ , Zr ⁴⁺ and Si ⁴⁺ . Among these metals, Al ³⁺ and Cr ³⁺ are preferable, and Al ³⁺ is particularly preferable. In the present invention, an aluminum compound of di-tert-butylsalicylic acid is particularly preferably used as the charge control agent.

  When the charge control agent is used in an amount of 0.1 to 10% by mass based on the mass of the toner, the initial fluctuation of the toner charge amount is small, and an absolute charge amount necessary for development can be easily obtained. This is preferable since there is no decrease in image quality such as density reduction.

  Next, a method for producing the toner of the present invention will be described. First, in the raw material mixing step, at least a binder resin and a colorant and, if necessary, other components are weighed and mixed as a toner internal additive constituting the toner particles, and mixed. Examples of the mixing apparatus include a double-con mixer, a V-type mixer, a drum-type mixer, a super mixer, a Henschel mixer, and a Nauter mixer.

  Next, the blended and mixed toner particle raw materials are melt-kneaded to melt the resins and disperse the colorant and the like therein. In the melt-kneading step, for example, a batch kneader such as a pressure kneader or a Banbury mixer, or a continuous kneader can be used. In recent years, single-screw or twin-screw extruders have become mainstream due to the advantage of being capable of continuous production. For example, KTK type twin screw extruder manufactured by Kobe Steel, TEM type twin screw extruder manufactured by Toshiba Machine Co., Ltd. In general, a twin-screw extruder manufactured by Kay Sea Kay, a co-kneader manufactured by Buss, or the like is used. Further, the colored resin composition obtained by melt-kneading the toner particle raw material is rolled by a two-roll or the like after being melt-kneaded, and then cooled through a cooling step of cooling by water cooling or the like.

  In general, the cooled colored resin composition obtained above is then pulverized to a desired particle size in a pulverization step. In the pulverization step, first, coarse pulverization is performed with a crusher, a hammer mill, a feather mill or the like, and further, pulverization is performed with a kryptron system manufactured by Kawasaki Heavy Industries, Ltd., a super rotor manufactured by Nisshin Engineering Co., Ltd. or the like. After that, if necessary, classification is performed using a classifier such as an inertia class elbow jet (manufactured by Nippon Steel & Mining Co., Ltd.) or a centrifugal class turbo turbo (manufactured by Hosokawa Micron Co., Ltd.), and the weight average particle diameter Is obtained as toner particles.

  In the present invention, after pulverizing with an air jet pulverizer without using mechanical pulverization in the pulverization step, classification and surface modification treatment using mechanical impact force as shown in FIGS. A classified product having a weight average particle diameter of 3 to 11 μm is obtained using an apparatus that is simultaneously used. Further, if necessary, a sieving machine such as a wind-type sieve high voltor (manufactured by Shin Tokyo Machine Co., Ltd.) may be used.

  Next, inorganic fine particles and, if necessary, other external additives are externally added to the obtained toner particles. As a method of external addition treatment, a predetermined amount of classified toner particles, the above-described inorganic fine particles (A) and inorganic fine particles (B), and various other known external additives are blended, such as a Henschel mixer, a super mixer, The toner of the present invention can be obtained by stirring and mixing using a high-speed stirrer that applies shearing force to the powder as an external additive.

  The apparatus used for producing the toner of the present invention will be described in detail below. As described above, in order to adjust the circularity of the toner within the above range, a surface modification process such as a pulverization process and / or a spheroidization process of toner particles is performed while discharging fine powder generated during the process to the outside of the system. It is preferable to carry out the treatment. FIG. 3 is a schematic cross-sectional view showing a process of an example of a surface modification apparatus preferably used for producing the toner of the present invention, and FIG. 4 is a schematic plan view showing the configuration of the dispersion rotor of FIG. 3 includes a casing 30, a jacket (not shown) through which cooling water or antifreeze liquid can pass, a square disk or cylindrical pin 40 attached to the central rotating shaft in the casing 30. The rotor is a disk-like rotating body that rotates at a high speed, and the surface of the dispersion rotor 36 is arranged on the outer periphery of the dispersion rotor 36 at a constant interval. Liner 34 (which does not have to have a groove on the liner surface), a classification rotor 31 which is a means for classifying the surface-modified raw material into a predetermined particle size, and cold air for introducing cold air Inlet port 35, raw material supply port 33 for introducing the raw material to be treated, discharge valve 38 installed so as to be openable and closable so that the surface modification time can be freely adjusted, and discharged powder after treatment You The powder discharge port 37, the space between the classification rotor 31 and the dispersion rotor 36-liner 34, the first space 41 before being introduced into the classification rotor 31 and the fine powder are classified and removed by the classification means. It is composed of a cylindrical guide ring 39 which is a guide means for partitioning the particles into a second space 42 for introducing the particles into the surface treatment means. A gap portion between the dispersion rotor 36 and the liner 34 is a surface modification zone, and the classification rotor 31 and its peripheral portion are classification zones.

  In the surface reforming apparatus configured as described above, when a finely pulverized product is introduced from the raw material supply port 33 with the discharge valve 38 closed, the introduced finely pulverized product is first sucked by a blower (not shown). And classified by the classification rotor 31. At that time, the classified fine powder having a predetermined particle diameter or less is continuously discharged and removed out of the apparatus, and the coarse powder having a predetermined particle diameter or more passes along the inner periphery (second space 42) of the guide ring 39 by centrifugal force. The circulating flow generated by the dispersion rotor 36 is guided to the surface modification zone.

  The raw material guided to the surface modification zone is subjected to a surface modification treatment by receiving a mechanical impact force between the dispersion rotor 36 and the liner 34. The surface-modified particles having undergone surface modification are guided to the classification zone along the outer periphery (first space 41) of the guide ring 39 on the cold air passing through the machine. The fine powder generated at this time is again discharged out of the machine by the classification rotor 31, and the coarse powder is returned to the surface reforming zone again through the circulating flow and repeatedly undergoes the surface reforming action. After a certain period of time, the discharge valve 38 is opened and the surface modified particles are recovered from the discharge port 37.

  As a result of investigations by the present inventors, in the surface modification step using the surface modification device, the time (cycle time) from the introduction of the finely pulverized product from the raw material supply port 33 to the release valve opening and the rotation of the dispersion rotor The number was found to be important in controlling the sphericity of the toner and the amount of release agent on the toner particle surface.

To increase the sphericity, it is effective to increase the cycle time or increase the peripheral speed of the dispersion rotor. In order to keep the amount of the release agent on the toner particle surface low, it is effective to shorten the cycle time or lower the peripheral speed. In particular, the toner cannot be efficiently spheroidized unless the peripheral speed of the dispersion rotor exceeds a certain level. Therefore, the cycle time must be increased to spheroidize, and the amount of surface release agent must be increased more than necessary. May end up. In order to improve the circularity of the toner while keeping the amount of the release agent on the surface of the toner particles below a predetermined value, and to make the circularity and transmittance of the toner within the above ranges, the peripheral speed of the dispersion roller is set to 1.2 × 10. It is effective to set the cycle time to 15 to 60 seconds at ⁵ mm / sec.

  In addition, the weight average particle diameter of the toner of the present invention is preferably 4 to 10 μm, and more preferably 5 to 9 μm. The toner of the present invention has a number average particle size of 3.5 to 9.5 μm, 5 to 50% by number of particles having a particle size of 4 μm or less in the toner number distribution, and a particle size in the toner volume distribution. It is preferable that the particle | grains of 12.70 micrometers or more are 5 volume% or less.

  When the weight average particle diameter of the toner is larger than 10 μm, it means that there are few fine particles that can contribute to high image quality, and it is easy to obtain a high image density and has the advantages of excellent toner fluidity. It is difficult to adhere faithfully on the fine electrostatic image above, and the reproducibility of the highlight portion is lowered, and the resolution is also lowered. In addition, the toner tends to overload the electrostatic charge image more than necessary, and the toner consumption tends to increase.

  On the contrary, when the weight average particle diameter of the toner is smaller than 4 μm, the charge amount per unit mass of the toner becomes high, and the decrease in image density, particularly the decrease in image density under low temperature and low humidity becomes remarkable. This is not particularly suitable for applications with a high image area ratio such as graphic images.

  When the thickness is smaller than 4 μm, contact charging with a charging member such as a carrier is difficult to be performed smoothly, toner that cannot be sufficiently charged increases, and fogging due to scattering to a non-image portion becomes conspicuous. In order to cope with this, it is conceivable to reduce the diameter of the carrier in order to increase the specific surface area of the carrier. However, with toner having a weight average diameter of less than 4 μm, toner self-aggregation easily occurs, and uniform mixing with the carrier can be achieved in a short time. In the continuous toner replenishment durability, fogging tends to occur.

  In the toner of the present invention, toner particles having a particle diameter of 4 μm or less are preferably 5 to 50% by number, more preferably 5 to 25% by number of the total number of particles. If the number of toner particles having a particle diameter of 4 μm or less is less than 5% by number, it means that there are few fine toner particles that are essential components for high image quality. As the toner is continuously used, the effective toner particle component is decreased, the balance of the particle size distribution of the toner shown in the present invention is deteriorated, and the image quality gradually decreases.

  Further, when the number of toner particles having a particle size of 4 μm or less exceeds 50% by number, the toner particles are likely to be agglomerated with each other and often behave as a toner lump having a particle size larger than the original particle size. An image is likely to be formed, the resolution is deteriorated, or the density difference between the edge portion and the inside of the electrostatic charge image is increased, and the image tends to be hollow. Furthermore, it is preferable for improving the image quality that the particle size is 12.70 μm or more is 7% by volume or less.

  Next, the shape of the toner that can be used in the present invention will be described in detail.

  As the shape of the toner that can be used in the present invention, the average circularity measured by FPIA2100 (manufactured by Sysmex Corporation) is preferably 0.920 to 0.970.

  The average circularity of the toner is measured using a flow type particle image measuring device “FPIA-2100 type” (manufactured by Sysmex Corporation), and is calculated using the following equation.

  Here, the “particle projected area” is the area of the binarized toner particle image, and the “peripheral length of the particle projected image” is the length of the contour line obtained by connecting the edge points of the toner particle image. Define. The measurement uses the perimeter of the particle image when image processing is performed at an image processing resolution of 512 × 512 (pixels of 0.3 μm × 0.3 μm).

  In the present invention, the circularity is an index indicating the degree of unevenness of the toner particles, and is 1.000 when the toner particles are completely spherical. The more complicated the surface shape, the smaller the circularity.

  The average circularity C, which means the average value of the circularity frequency distribution, is calculated from the following equation, where ci is the circularity (center value) at the dividing point i of the particle size distribution and m is the number of measured particles.

  In addition, “FPIA-2100”, which is a measuring apparatus used in the present invention, calculates the circularity of each particle, and then calculates the average circularity. 1.0 is divided into classes equally divided every 0.01, and the average circularity is calculated using the center value of the division points and the number of measured particles.

  As a specific measuring method, 10 ml of ion-exchanged water from which impure solids have been removed in advance is prepared in a container, and a surfactant, preferably an alkylbenzene sulfonate, is added as a dispersant therein, followed by further measurement. Add 0.02 g of sample and disperse uniformly. As a means for dispersion, an ultrasonic disperser “Tetora 150 type” (manufactured by Nikka Ki Bios Co., Ltd.) is used, and dispersion treatment is performed for 2 minutes to obtain a dispersion for measurement. In that case, it cools suitably so that the temperature of this dispersion may not be 40 degreeC or more. In order to suppress variation in circularity, the installation environment of the apparatus is controlled at 23 ° C. ± 0.5 ° C. so that the temperature inside the flow type particle image analyzer FPIA-2100 is 26 to 27 ° C. Preferably, autofocus is performed using 2 μm latex particles every 2 hours.

  To measure the circularity of the toner particles, the flow type particle image measuring device is used, and the concentration of the dispersion is readjusted so that the toner particle concentration at the time of measurement is 3000 to 10,000 particles / μl. Measure more than one. After the measurement, using this data, data having an equivalent circle diameter of less than 2 μm is cut to determine the average circularity of the toner particles.

  Furthermore, “FPIA-2100”, which is a measuring apparatus used in the present invention, has a thinner sheath flow (7 μm) than “FPIA-1000” that has been used to calculate the shape of the toner. (To 4 μm) and the processing particle image magnification, and the processing resolution of the captured image is improved (256 × 256 → 512 × 512), so that the accuracy of toner shape measurement is improved, thereby making sure the fine particles are more reliable. A device that has achieved supplementation. Therefore, when it is necessary to measure the shape more accurately as in the present invention, the FPIA 2100 that can obtain information on the shape more accurately is more useful.

  When the average circularity is less than 0.920, the transferability of the toner is deteriorated, and the transfer residual toner may be excessively accumulated on the charging member to cause a charging failure. In addition, since the ratio of the inorganic fine particles having an abrasive action to the concave and convex portions on the surface of the toner increases, the effect of removing the charged product cannot be sufficiently obtained.

  When the average circularity is larger than 0.970, the toner fluidity is likely to occur because the fluidity as the toner is too good.

  Therefore, the shape of the toner is preferably within the above range, but in the present invention, this range can be achieved by adjusting the pulverization condition and surface treatment modification condition of the toner.

The toner of the present invention can be applied to both a one-component developer composed only of toner (not including a carrier) and a two-component developer composed of a toner and a carrier. When the toner is used as a two-component developer, the toner is mixed with a magnetic carrier. The magnetic carrier that can be used in the present invention is preferably a magnetic carrier in which a coating layer is formed on the surface of a known ferrite particle or magnetic fine particle-dispersed resin core, particularly preferably a coating layer on the surface of the magnetic fine particle-dispersed resin core. Is a magnetic carrier. In the magnetic carrier that can be used in the present invention, the magnetic fine particles used in the magnetic fine particle dispersed resin core are preferably magnetite fine particles, and are nonmagnetic inorganic compounds for adjusting the true density and magnetic properties of the magnetic carrier. It is preferable to use certain hematite (α-Fe ₂ O ₃ ) fine particles in combination.

  As the binder resin constituting the magnetic fine particle dispersed resin core particles that can be used in the present invention, a thermosetting resin is preferable.

  Thermosetting resins include phenolic resins, epoxy resins, polyamide resins, melamine resins, urea resins, unsaturated polyester resins, alkyd resins, xylene resins, acetoguanamine resins, furan resins, silicone resins, polyimide resins, urethane resins. Is mentioned. These resins may be used alone or in combination of two or more, but preferably contain at least a phenol resin.

  The ratio of the binder resin and the magnetic fine particles constituting the core particles in the present invention is preferably binder resin: magnetic fine particles = 1: 99 to 1:50 on a mass basis.

  In the present invention, the carrier coating material preferably contains at least a binder resin and fine particles.

  As the binder resin for forming the coating material used for the magnetic carrier that can be used in the present invention, any known resin can be used. Preferably, polyvinyl fluoride, polyvinylidene fluoride, polytrifluoroethylene, Perfluoropolymers such as polyfluorochloroethylene, polytetrafluoroethylene, polyperfluoropropylene, copolymers of vinylidene fluoride and acrylic monomers, copolymers of vinylidene fluoride and trifluorochloroethylene, tetrafluoro Examples thereof include a copolymer of ethylene and hexafluoropropylene, a copolymer of vinyl fluoride and vinylidene fluoride, and a copolymer of vinylidene fluoride and tetrafluoroethylene.

  The above-mentioned resins can be used alone or in combination. In addition, a curing agent or the like can be mixed with a thermoplastic resin and cured for use.

  In the present invention, a silicone resin can also be used as the coating material resin from the viewpoint of adhesion to the core and prevention of spent. The silicone resin can be used alone, but is preferably used in combination with a coupling agent in order to increase the strength of the coating layer and control the charge to a preferable level. Furthermore, the coupling agent described above is preferably used as a so-called primer agent in which a part of the coupling agent is treated on the surface of the carrier core before coating the resin, and the subsequent coating layer is accompanied by a covalent bond. , It can be formed in a more adhesive state.

  Aminosilane is preferably used as the coupling agent. As a result, an amino group having positive chargeability can be introduced on the surface of the carrier, and negative charge characteristics can be imparted to the toner satisfactorily. Furthermore, in the case of a magnetic substance-dispersed resin carrier, the presence of an amino group activates both the lipophilic treatment agent that is preferably treated with the metal compound and the silicone resin. By further enhancing the properties and at the same time promoting the curing of the resin, a stronger coating layer can be formed.

  The coating amount of the resin core forming the coating material is preferably 0.3 to 4.0 parts by mass with respect to 100 parts by mass of the core. Preferably it is 0.4 thru | or 3.5 mass part, More preferably, it is 0.5 mass part thru | or 3.2 mass part.

  The coating resin preferably contains fine particles in order to make the shape of the carrier surface more uniform and / or sharpen the charge distribution of the toner.

  As the fine particles, both organic and inorganic fine particles can be used. However, it is necessary to maintain the shape of the particles when the carrier is coated, and preferably, crosslinked resin particles or inorganic fine particles are preferably used. Can do. Specifically, a crosslinked polymethyl methacrylate resin, a crosslinked polystyrene resin, a melamine resin, a phenol resin, a nylon resin, and inorganic fine particles can be used alone or in combination from silica, titanium oxide, alumina, and the like. Among these, a crosslinked polymethyl methacrylate resin, a crosslinked polystyrene resin, and a melamine resin are preferable from the viewpoint of charge stability.

  These fine particles are preferably used in an amount of 1 to 40 parts by mass with respect to 100 parts by mass of the coating resin. By using it in the above range, charging stability and toner separation can be improved, and image defects can be prevented. When the amount is less than 1 part by mass, the effect of addition of fine particles cannot be obtained, and when the amount exceeds 40 parts by mass, the coating layer lacks during durability, resulting in poor durability.

  The coating resin may contain conductive fine particles so as not to reduce the specific resistance of the carrier excessively and to remove residual charges on the surface of the carrier.

  As the conductive particles, for example, particles containing at least one kind of particles selected from carbon black, magnetite, graphite, titanium oxide, alumina, zinc oxide, and tin oxide are preferable. In particular, as a conductive particle, carbon black is preferably used without being able to remove residual charges on the carrier surface with a small addition amount, and having a small particle size and not inhibiting irregularities caused by fine particles on the carrier surface. be able to.

  These conductive fine particles are preferably used in an amount of 1 to 15 parts by mass with respect to 100 parts by mass of the coating resin in order to reduce the specific resistance of the carrier and to remove residual charges on the carrier surface. When the amount is less than 1 part by mass, the effect of removing the residual charge on the carrier surface is hardly exhibited. When the amount exceeds 15 parts by mass, the dispersion in the coating material becomes unstable, and an excessive charge removing effect is obtained. Therefore, the charge imparting ability of the carrier itself may be reduced.

  The magnetic carrier that can be used in the present invention preferably has a number-based average particle size of 10 to 80 μm. Particles having an average particle size of less than 10 μm are likely to adhere to the carrier, and particles having an average particle size of more than 80 μm may not be able to be imparted with good charge due to a small specific surface area relative to the toner. In particular, in order to improve image quality and prevent carrier adhesion, the thickness is 15 to 60 μm, preferably 20 to 45 μm.

  The average particle diameter of the magnetic carrier is extracted as 300 or more carrier particles having a particle diameter of 0.1 μm or more randomly with a scanning electron microscope (100 to 5000 times), and measured as a carrier particle diameter with a horizontal ferret diameter using a digitizer. The number average particle diameter of the carrier is calculated.

  As a method for producing a magnetic fine particle-dispersed resin core, there is a method in which a binder resin monomer and magnetic fine particles are mixed and the monomer is polymerized to obtain magnetic fine particle-dispersed core particles. At this time, as monomers used for polymerization, vinyl monomers, bisphenols and epichlorohydrin for forming epoxy resins; phenols and aldehydes for forming phenol resins; urea and aldehydes for forming urea resins Melamine and aldehydes are used. For example, as a method of producing magnetic fine particle dispersed core particles using a curable phenolic resin, magnetic fine particles are placed in an aqueous medium, and phenols and aldehydes are polymerized in the presence of a basic catalyst in the aqueous medium. There is a method of obtaining fine particle dispersed core particles.

  Other methods for producing magnetic fine particle-dispersed resin core particles include thoroughly mixing a vinyl-based or non-vinyl-based thermoplastic resin, magnetic material, and other additives with a mixer before heating rolls, kneaders, and extruders. There is a method of obtaining magnetic fine particle-dispersed core particles by melting and kneading using a kneader such as the above, cooling the mixture, and then pulverizing and classifying. At this time, it is preferable that the obtained magnetic fine particle-dispersed core particles are spheroidized thermally or mechanically and used as the magnetic fine particle-dispersed core particles for the resin carrier. As the binder resin, a thermosetting resin such as a phenol resin, a melamine resin, or an epoxy resin is preferable in terms of excellent durability, impact resistance, and heat resistance. The binder resin is more preferably a phenol resin in order to more suitably express the characteristics of the present invention.

  When a two-component developer is prepared by mixing the toner of the present invention and a magnetic carrier, the mixing ratio is usually 2 to 15% by mass, preferably 4 to 13% by mass, as the toner concentration in the developer. Good results are obtained. If the toner concentration is less than 2% by mass, the image density tends to decrease, and if it exceeds 15% by mass, fogging or in-machine scattering tends to occur.

  The image forming method of the present invention will be described in detail.

  An example of a simultaneous development cleaning method using the image forming method of the present invention is shown in FIG. In FIG. 5, the electrophotographic photosensitive member 1 which is an electrostatic latent image carrier rotates in the b direction. The photosensitive member 1 is charged by a charging device 2 as a charging unit, and a laser beam L is projected onto the charged surface of the photosensitive member 1 by an exposure device 3 as an electrostatic latent image forming unit to form an electrostatic latent image. . Thereafter, the electrostatic latent image is visualized as a toner image by the developing device 4 that is a developing unit, and is transferred to the transfer material P by the transfer device 5 that is a transfer unit. In this transfer unit, the untransferred toner remaining on the surface of the photosensitive member without being transferred passes through the above-described charging unit and electrostatic latent image forming unit, and is again used for development or collected by the developing device.

  Here, each step of the image forming method that can be used in the present invention will be described in more detail.

  The charging step is not particularly limited as long as it is a means for charging the surface of the photoconductor to charge the electrophotographic photoconductor. As the charging means, a device for charging the electrophotographic photosensitive member without contact with the electrophotographic photosensitive member, such as a corona charging means, or an electrophotographic photosensitive member by contacting a conductive roller or blade with the electrophotographic photosensitive member. Devices that charge the body can be used.

  In the present invention, the contact charging method is preferable from the viewpoint of the charged product. Corona discharge, which is a conventional non-contact charging method, generates a large amount of ozone that reacts with nitrogen in the air to form nitrogen oxides (NOx), and these nitrogen oxides react with moisture in the air to form nitric acid. It adheres to the surface of the photoreceptor and tends to reduce the resistance of the surface of the photoreceptor. On the other hand, in the contact charging method, the amount of ozone generated is remarkably small, and the change in the resistance of the photoreceptor surface due to the charged product is small. Further, the contact charging method is more preferable because the charged product that causes the image flow can be efficiently removed by the polishing action of the inorganic fine particles contained in the transfer residual toner in the contact area with the photoreceptor.

  The contact charging method includes a discharge charging mechanism such as a roller charging method and a direct injection charging mechanism such as a magnetic brush charging method.

  The discharge charging mechanism is a mechanism in which the surface of the member to be charged is charged by a discharge phenomenon that occurs in the gap between the contact charging member and the member to be charged. Since the discharge charging system has a constant discharge threshold value for the contact charging member and the member to be charged, it is necessary to apply a voltage larger than the potential of the member to be charged to the contact charging member. In addition, the amount of generation is much smaller than that of a corona charger, but in principle, a charged product is generated.

As a contact charging member by discharge, a roller charging method (roller charging device) using a conductive roller (charging roller) is preferable in terms of discharge stability and is widely used. The discharge charging roller may be formed in a roller shape using a conductive or medium resistance rubber material or foam as a base layer, and the surface thereof may be made of a high resistance layer. In this configuration, the discharge phenomenon occurs in a gap of several tens of μm that is slightly away from the contact portion between the roller and the member to be charged. Therefore, in order to stabilize the discharge phenomenon, a layer on the roller surface (hereinafter referred to as a surface layer) is flat, has an average surface roughness Ra of 1.0 μm or less, and has a surface with high roller hardness. Preferably it is. In addition, the roller charging due to the discharge has a high applied voltage, and if there is a pinhole (exposed substrate due to damage to the film to be charged), a voltage drop and a charging failure are likely to occur around it. Therefore, the surface resistance of the surface layer is preferably 10 ¹¹ Ω or more from the viewpoint of preventing a voltage drop.

  The direct injection charging mechanism is a charging mechanism that charges (charges) the surface of a member to be charged by directly transferring and receiving charges by contacting the contact charging member and the member to be charged at the molecular level. It is also called direct charging or injection charging.

  As the contact charging member by injection, a magnetic brush charging method (magnetic brush charging device) using a magnetic brush is preferably used. The magnetic brush charging uses a member having a magnetic brush portion formed in a brush shape by magnetically constraining conductive magnetic particles with a magnet roll or the like as a contact charging member, and the magnetic brush portion is contacted with a photosensitive member as a charged body. Then, a predetermined charging bias is applied to charge the photoreceptor surface to a predetermined polarity and potential.

  It is preferable to perform direct injection charging uniformly by using particles having an average particle diameter of 5 to 50 μm on a number basis as the conductive magnetic particles constituting the magnetic brush portion and providing a sufficient speed difference from the photoreceptor. Magnetic brush charging also has problems such as complicated equipment configuration and conductive magnetic particles constituting the magnetic brush portion falling off and adhering to the photoreceptor.

  The average particle size of the conductive magnetic particles is determined by randomly extracting 300 or more conductive magnetic particles having a particle size of 0.1 μm or more with a scanning electron microscope (100 to 5000 times), and using a digitizer as a particle size with a horizontal ferret diameter. Measure and calculate the number average particle diameter of the conductive magnetic particles.

  In the direct injection charging mechanism, the potential difference between the contact charging member and the member to be charged is about several volts to several tens of volts. The charging potential is equal to the applied voltage, and there is no voltage difference that causes discharge. In addition, the voltage required for charging can be kept low. Since this direct charging system does not involve the generation of ions, no adverse effects caused by the discharge products occur. That is, it is a charging method that is excellent in terms of low power without generating ozone.

  As the mechanism of the contact charging method, the above two methods can be mentioned, but neither of them generates a large amount of ozone in the conventional non-contact charging method using corona discharge, from the viewpoint of suppression of charged products and low power. Preferably used.

  In the electrostatic latent image forming step, a known exposure apparatus can be used as the exposure means. For example, a semiconductor laser or a light emitting diode is used as the light source, and a scanning optical system unit including a polygon mirror, a lens, and a mirror can be used.

  The development process is mainly divided into a one-component contact development method that does not require a carrier and a two-component development method that includes a toner and a carrier, and any of them can be used. In the present invention, a two-component development method is preferably used from the viewpoint of suppressing and removing deposits on the surface of the photoreceptor.

  As a two-component development method, a magnetic brush of a two-component developer having a nonmagnetic toner and a magnetic carrier is formed on a developer carrier (development sleeve) containing a magnet, and the magnetic brush is formed with a developer layer thickness. After coating with a regulating member to a predetermined layer thickness, the magnetic brush is transported to a developing area facing the photoreceptor, and the magnetic brush is applied while applying a predetermined developing bias between the photoreceptor and the developing sleeve in the developing area. Is a method in which the electrostatic latent image is visualized as a toner image by bringing the toner close to or in contact with the surface of the photoreceptor.

  As described above, by bringing the magnetic brush close to or in contact with the surface of the photoconductor, the deposits on the surface of the photoconductor can be reduced, and the surface of the photoconductor can be reduced by the inorganic fine particles contained in the toner. This is preferably used because it can effectively remove the deposits.

  Examples of the magnetic carrier that can be used in such a two-component developer include an iron powder carrier, a ferrite carrier, and a magnetic fine particle dispersed resin carrier in which magnetic fine particles are dispersed in a binder resin. In the iron powder carrier, since the specific resistance of the carrier itself is low, the charge of the electrostatic latent image leaks through the carrier, and the electrostatic latent image may be disturbed, thereby causing an image defect. Also, in the ferrite carrier, although the specific resistance of the carrier itself is relatively high, the magnetic brush tends to be stiff due to the large saturation magnetization, and the magnetic brush has uneven spots on the toner image. There is. Therefore, a magnetic fine particle dispersed resin carrier in which magnetic fine particles are dispersed in a binder resin is preferably used. The magnetic fine particle-dispersed resin carrier has a relatively higher specific resistance than that of a ferrite carrier, has a lower saturation magnetization, and a lower true specific gravity, thereby preventing electrostatic latent image charge leakage and a rigid magnetic brush. Therefore, it is preferable in that a good toner image free from image defects and unevenness in stitches can be formed.

  In the transfer process, the toner image on the surface of the photoconductor is transferred to the transfer material without contact with the photoconductor, such as corona transfer means, or a roller or an endless belt-shaped transfer member is brought into contact with the photoconductor. There are methods for transferring a toner image on the body surface onto a transfer material, and any method can be used.

  In the present invention, as in the charging step, a large amount of ozone is not generated, and a contact type transfer roller, a resin belt, or an elastic belt-like transfer member is preferably used from the viewpoint of suppression of charged products and low power. It is done.

  Further, in the image forming method of the present invention, as shown in FIG. 6, the transfer residual toner on the photosensitive member is leveled after the transfer and before the charging step, thereby improving the recovery rate of the transfer residual toner at the time of development. Therefore, it is preferable to further include a leveling step 6 having a bias applying means for the purpose of uniformizing the charging polarity of the transfer residual toner.

  In the leveling step 6, when the toner is negatively charged, it is preferable to apply a bias for negatively charging the transfer residual toner to reduce adhesion of the transfer residual toner to the charging member in the charging step. This improves the recovery rate of the transfer residual toner during development. Further, as the leveling member, a brush-like member is preferably used. Furthermore, it is preferable to provide a plurality of such leveling members because the transfer residual toner adheres to the charging member and the recovery rate of the transfer residual toner during development increases.

  Hereinafter, methods for analyzing and measuring other physical properties related to the present invention will be described.

<Measurement of particle size of inorganic fine particles>
The particle size of the inorganic fine particles was obtained by randomly extracting 500 particles having a particle size of 5 nm or more with a scanning electron microscope (50,000 times), measuring the major and minor axes with a digitizer, and averaging the particles. The average particle size is calculated with the mode diameter that is the peak of the particle size distribution of 500 or more particles (from the column histogram divided every 10 nm).

<Molecular weight distribution of binder resin, toner, and coating resin by GPC measurement>
The molecular weight of the chromatogram by gel permeation chromatography (GPC) is measured under the following conditions. For the measurement, HLC-8120GPC (manufactured by Tosoh Corporation) was used.

The column was stabilized in a heat chamber at 40 ° C., and tetrahydrofuran (THF) as a solvent was passed through the column at this temperature at a flow rate of 1 ml / min, and the sample concentration was adjusted to 0.05 to 0.6% by mass. About 50 to 200 μl of THF sample solution is injected and measured. In measuring the molecular weight of a sample, the molecular weight distribution of the sample is calculated from the relationship between the logarithmic value of a calibration curve prepared from several types of monodisperse polystyrene standard samples and the number of counts (retention time). Examples of standard polystyrene samples for preparing a calibration curve include those manufactured by Tosoh Corporation or Pressure Chemical Co. The molecular weights manufactured are 6 × 10 ² , 2.1 × 10 ³ , 4 × 10 ³ , 1.75 × 10 ⁴ , 5.1 × 10 ⁴ , 1.1 × 10 ⁵ , 3.9 × 10 ⁵ , 8 ^{.6 × 10 5, 2 × 10} 6, used as a 4.48 × 10 ^6, it is appropriate to use at least about 10 standard polystyrene samples. An RI (refractive index) detector is used as the detector.

As a column, in order to accurately measure a molecular weight region of 10 ^{3 to} 2 × 10 ⁶ , it is preferable to combine a plurality of commercially available polystyrene gel columns. For example, shodex GPC KF-801, 802, 803 manufactured by Showa Denko KK , 804, 805, 806, and 807, and combinations of μ-styragel 500, 10 ³ , 10 ⁴ , and 10 ⁵ manufactured by Waters.

<Measurement of maximum endothermic peak in DSC of toner and wax>
The maximum endothermic peak of the toner and the wax can be measured according to ASTM D3418-82 using a differential thermal analyzer (DSC measuring device) and DSC2920 (TA Instruments Japan).
Temperature curve: Temperature increase I (30 ° C. to 200 ° C., temperature increase rate 10 ° C./min)
Temperature drop I (200 ° C-30 ° C, temperature drop rate 10 ° C / min)
Temperature increase II (30 ° C. to 200 ° C., temperature increase rate 10 ° C./min)

  As a measuring method, 5 to 20 mg, preferably 10 mg of a measurement sample is accurately weighed. This is put into an aluminum pan, and an empty aluminum pan is used as a reference, and measurement is performed at a temperature rise rate of 10 ° C./min and normal temperature and humidity in a measurement temperature range of 30 to 200 ° C. The maximum endothermic peak of the toner is determined in the process of temperature increase II, the one having the highest height from the baseline in the region above the endothermic peak of the resin Tg, or the endothermic peak of the resin Tg overlaps with another endothermic peak. If this is difficult, the maximum endothermic peak of the toner of the present invention is defined as the highest peak from the maximum peak of the overlapping peaks.

<Measurement of toner particle size distribution>
As a measuring device, Coulter Counter TA-II or Coulter Multisizer II (manufactured by Coulter Inc.) is used. As the electrolytic solution, an about 1% NaCl aqueous solution is used. As the electrolytic solution, an electrolytic solution prepared using primary sodium chloride or, for example, ISOTON (registered trademark) -II (manufactured by Coulter Scientific Japan) can be used.

  As a measurement method, 0.1 to 5 ml of a surfactant (preferably alkylbenzenesulfone hydrochloride) is added as a dispersant to 100 to 150 ml of the electrolytic aqueous solution, and 2 to 20 mg of a measurement sample is further added. The electrolytic solution in which the sample is suspended is dispersed for about 1 to 3 minutes with an ultrasonic disperser, and the volume and number of the sample are measured for each channel by the measuring device using a 100 μm aperture as the aperture. The volume distribution and the number distribution are calculated. From these obtained distributions, the weight average particle diameter of the sample is determined. As channels, 2.00 to 2.52 μm; 2.52 to 3.17 μm; 3.17 to 4.00 μm; 4.00 to 5.04 μm; 5.04 to 6.35 μm; 6.35 to 8. 00 μm; 8.00 to 10.08 μm; 10.08 to 12.70 μm; 12.70 to 16.00 μm; 16.00 to 20.20 μm; 20.20 to 25.40 μm; 25.40 to 32.00 μm; 13 channels of 32-40.30 μm are used.

  Hereinafter, the present invention will be described in more detail with reference to specific production examples and examples, but the present invention is not limited thereto.

(Example of hybrid resin production)
As a vinyl polymer, 1.9 mol of styrene, 0.21 mol of 2-ethylhexyl acrylate, 0.15 mol of fumaric acid, 0.03 mol of α-methylstyrene dimer, and 0.05 mol of dicumyl peroxide were placed in a dropping funnel. . In addition, 7.0 mol of polyoxypropylene (2.2) -2,2-bis (4-hydroxyphenyl) propane, polyoxyethylene (2.2) -2,2-bis (4-hydroxyphenyl) propane; 0 mol, 3.0 mol of terephthalic acid, 2.0 mol of trimellitic anhydride, 5.0 mol of fumaric acid and 0.2 g of dibutyltin oxide are placed in a 4-liter four-necked flask made of glass, a thermometer, a stirring rod, a condenser and nitrogen The introduction tube was installed and placed in a mantle heater. Next, after the inside of the flask was replaced with nitrogen gas, the temperature was gradually increased while stirring, and while stirring at a temperature of 145 ° C., the monomer of the vinyl resin, the crosslinking agent and the polymerization initiator were added from the previous dropping funnel. It was dripped over 4 hours. Next, the temperature was raised to 200 ° C. and reacted for 4 hours to obtain a hybrid resin. Table 1 shows the results of molecular weight measurement by GPC (gel permeation chromatography). In Table 1, Mw is a weight average molecular weight, Mn is a number average molecular weight, and Mp is a peak molecular weight.

(Example of polyester resin production)
3.6 mol of polyoxypropylene (2.2) -2,2-bis (4-hydroxyphenyl) propane, 1.6 mol of polyoxyethylene (2.2) -2,2-bis (4-hydroxyphenyl) propane, 1.7 mol of terephthalic acid, 1.1 mol of trimellitic anhydride, 2.4 mol of fumaric acid and 0.1 g of dibutyltin oxide are placed in a 4-liter 4-neck flask made of glass, a thermometer, a stir bar, a condenser and a nitrogen inlet tube Was installed in a mantle heater. Under a nitrogen atmosphere, reaction was performed at 215 ° C. for 5 hours to obtain a polyester resin. The results of molecular weight measurement by GPC are shown in Table 1.

(Production example of magnetic fine particle dispersed resin core)
A magnetic fine particle-dispersed resin core (R-1) was prepared using the following materials.
-Phenol 10 parts by mass-Formaldehyde solution (37% by mass aqueous solution) 6 parts by mass-Magnetite particles 76 parts by mass-Hematite particles 8 parts by mass The above materials, 28 parts by mass ammonia water 5 parts by mass and water 10 parts by mass are placed in a flask. The mixture was heated and maintained at 85 ° C. for 30 minutes while stirring and mixing, and was cured by polymerization for 3 hours. Then, after cooling to 30 degreeC and adding water, the supernatant liquid was removed, the precipitate was washed with water, and then air-dried. Subsequently, this was dried under reduced pressure (5 hPa or less) at a temperature of 60 ° C. to obtain a magnetic fine particle dispersed resin core (R-1) in which magnetic fine particles were dispersed.

(Example of coating material for coating layer)
3 parts by mass of a methyl methacrylate macromer having an ethylenically unsaturated group at one end and a weight average molecular weight of 5,000, 46 parts by mass of a monomer having the following compound (d) as a unit, 51 parts by mass of methyl methacrylate, It is added to a four-necked flask equipped with a thermometer, a nitrogen suction tube and a mixing type stirring apparatus, and further 100 parts by mass of toluene, 100 parts by mass of methyl ethyl ketone, 2.4 parts by mass of azobisisovaleronitrile are added, The graft copolymer solution (solid content 35 mass%) was obtained by maintaining at 10 ° C. for 10 hours. The weight average molecular weight according to gel permeation chromatogram (GPC) of the graft copolymer was 20,000.

  0.7 parts by mass of melamine resin (number average particle diameter 0.25 μm), carbon black (number average particle diameter 35 nm, DBP oil absorption 50 ml / 100 g) with respect to 30 parts by mass of the obtained graft copolymer solution 2 parts by mass and 100 parts by mass of toluene were stirred with a homogenizer to obtain a coating material (L-1).

(Example of magnetic carrier production)
While stirring 100 mass parts of the magnetic fine particle dispersed resin core (R-1) while continuously applying shear stress, the coating material (L-1) is gradually added, and the solvent is volatilized at 70 ° C. A resin coat was applied to The resin-coated magnetic carrier particles were heat-treated with stirring at 100 ° C. for 2 hours, pulverized, and then classified with a sieve having an aperture of 76 μm. The average particle size was 35 μm, the specific resistance was 5.9 × 10 ⁹ Ω · A magnetic carrier (C-1) having cm, true specific gravity of 3.6 g / cm ³ , magnetization strength (σ1000) of 51.2 Am ² / kg, and residual magnetization of 4.9 Am ² / kg was obtained.

<Example 1>
Cyan toner 1 was prepared by the following method.
・ Hybrid resin 100 parts by mass I. Pigment Blue 15: 3 5 parts by mass / normal paraffin wax (maximum thermal peak: 78 ° C.) 5 parts by mass / aluminum compound of di-tert-butylsalicylic acid (charge control agent) 2.0 parts by mass The mixture was sufficiently premixed and melt-kneaded at an arbitrary barrel temperature with a twin-screw extrusion kneader. After cooling, it was coarsely pulverized to about 1 to 2 mm using a hammer mill, and then finely pulverized to a particle size of 20 μm or less with an air jet fine pulverizer. Further, the obtained finely pulverized product was classified and spheroidized by an apparatus for simultaneously performing classification and surface modification treatment using mechanical impact force as shown in FIGS. 3 and 4, and the volume average particle size distribution was 5.5 μm. Cyan resin particles (classified product) were obtained as colored particles.

The inorganic fine particles (A) used in the examples are shown in Table 2, and the inorganic fine particles (B) are shown in Table 3, respectively. Further, hydrophobic silica having an average primary particle diameter Dc of 45 nm (BET specific surface area of 130 m ² / g) was used as the inorganic fine particles (C).

  1.0 part by mass of the inorganic fine particles A-1 shown in Table 2 with respect to 100 parts by mass of the cyan resin particles, 1.5 parts by mass of the inorganic fine particles B-1 shown in Table 3, and 1 for the inorganic fine particles (C). 0.0 parts by mass of external addition was carried out to obtain cyan toner 1 having an average circularity of 0.935 in particles of 2 μm or more. 8 parts by mass of this cyan toner 1 and 92 parts by mass of magnetic carrier (C-1) were mixed by a tumbler mixer to obtain a cyan developer 1.

  Table 4 shows the toner formulation, Db / Da, and the release rate of inorganic fine particles.

Next, using a Canon full color copying machine iRC3200, N / N (23 ° C., 50% RH) under normal temperature and humidity, L / L (15 ° C., 10% RH) under low temperature and low humidity, H / H under high temperature and high humidity. Image output and evaluation were performed while supplying toner at H (30 ° C., 80% RH). Durability was performed up to 10,000 sheets each while adjusting the development bias so that the image printing ratio was 8% and the toner loading on the transfer material (paper) was 0.55 mg / cm ² . The evaluation items and evaluation criteria are shown below. The obtained evaluation results are shown in Table 5.

[Evaluation item]
<Durability stability>
The image density of the initial and 10000th solid images in a low-temperature and low-humidity environment and a high-temperature and high-humidity environment was measured, and the density difference was calculated. This density difference was used as an index of the durability stability of the toner. The image density was measured with the above-described X-Rite color reflection densitometer (X-rite 500 Series, manufactured by X-rite), and an average value of 6 points was used.
A: Very good (less than 0.08)
B: Good (0.08 or more, less than 0.15)
C: Normal (0.15 or more, less than 0.25)
D: Slightly bad (0.25 or more, less than 0.35: lower limit of practical level)
E: Poor (0.35 or more: Unusable level)

<Fog>
Under the high temperature and high humidity environment, the whiteness of each of the paper that output the solid white image and the same unused white paper was measured in the initial stage and after the image output was completed, and the fog was calculated from the difference in whiteness. The whiteness was measured by a reflectometer (“REFLECTOMETER MODEL TC-6DS” manufactured by Tokyo Denshoku Co., Ltd.) equipped with a color filter, and an average value of 6 points was used.
A: Very good (less than 1.0%)
B: Good (1.0% or more and less than 2.0%)
C: Normal (2.0% or more, less than 3.5%)
D: Somewhat bad (3.5% or more, less than 5.0%: practical use lower limit)
E: Bad (5.0% or more)

<Transfer efficiency>
In a normal temperature and humidity environment, after initial and image output, the potential contrast of the photoconductor was adjusted so that the amount of toner applied on the photoconductor was 0.55 mg / cm ² , and transferred onto transfer paper. The image density of the image and the untransferred image on the photoconductor was measured using an X-Rite color reflection densitometer.

In the measurement, the developer on the image on the transfer paper and the image remaining on the photoconductor was collected by taping, and the image density of the tape stuck on the paper was measured. From the obtained image density, the loading amount of the developer on the transfer paper and the photoconductor was converted to obtain the transfer efficiency onto the transfer paper. The transfer current used was adjusted to maximize transfer efficiency. The image density obtained by taping the remaining transfer portion of the photoreceptor and pasting it on the paper is D1, and the image density obtained by taping on the developer transferred onto the paper and sticking it on the paper is D2. Efficiency was calculated.
Transfer efficiency (%) = D2 / (D1 + D2) × 100

The obtained transfer efficiency was evaluated based on the following evaluation criteria.
A: Very good (transfer efficiency 94% or more)
B: Good (transfer efficiency 90% or more, less than 94%)
C: Normal (transfer efficiency 85% or more, less than 90%)
D: Slightly bad (transfer efficiency 80% or more, less than 85%: practical use lower limit)
E: Poor (transfer efficiency less than 80%: impractical level)

<Fusion and filming>
After image output under a high temperature and high humidity environment was completed, a 30H image was formed, and the image and the surface of the photoreceptor were visually observed. The reproducibility of the solid uniformity of the image was evaluated using the following indices. Note that the 30H image is a halftone image when 256 gradations are displayed in hexadecimal, 00H is solid white, and FFH is solid.
A: There are no streaks or unevenness on the image, and there is no fusion or filming on the surface of the photoreceptor.
B: There are no streaks or unevenness, but slight fusing and filming are observed on the surface of the photoreceptor.
C: Slight streaks / unevenness is observed, and fusion and filming are observed on the surface of the photoreceptor (the practical level lower limit).
D: There are many streaks and irregularities, and remarkable fusion and filming of the photoreceptor surface are observed (impractical level).

<Image flow>
After the image output under the high temperature and high humidity environment is completed, the intermediate transfer member is released from the photosensitive member, and only the photosensitive member is rotated for 30 minutes while applying the charging bias, and then stopped. Left for hours. Thereafter, the developing unit and the intermediate transfer member were returned to normal, and a character pattern with a printing ratio of 5% was drawn until the image flow disappeared. The following ranking was performed according to the number of images that could not be recognized.
A: Less than 5 sheets B: 5 sheets or more, less than 10 sheets C: 11 sheets or more, less than 25 sheets (practical level lower limit)
D: 25 or more (practical level)

<Examples 2 to 12>
In Example 1, images were evaluated and evaluated in the same manner as in Example 1 except that the toner shown in Table 4 was used instead of cyan toner 1. The evaluation results are shown in Table 5. In Example 8, since the black toner 2 is a magnetic one-component toner, the image was printed and evaluated without using a carrier.

<Comparative Examples 1-4>
In Example 1, images were evaluated and evaluated in the same manner as in Example 1 except that the toner shown in Table 4 was used instead of cyan toner 1. The evaluation results are shown in Table 5.

It is a figure which shows an example of the X-ray-diffraction pattern of an amorphous inorganic fine particle. It is a figure which shows an example of the X-ray diffraction pattern of crystalline inorganic fine particles. It is a schematic sectional drawing of the surface modification apparatus of an example used in the surface modification process of this invention. It is the schematic which shows an example of the top view of the dispersion | distribution rotor shown in FIG. It is a schematic diagram showing an example of an image forming apparatus using the image forming method of the present invention. It is a schematic diagram showing an example of an image forming apparatus using the image forming method of the present invention.

Explanation of symbols

31 Classification rotor 32 Fine powder collection port 33 Raw material supply port 34 Liner 35 Cold air introduction port 36 Dispersion rotor 37 Product discharge port 38 Discharge valve 39 Guide ring 40 Square disk 41 First space 42 Second space

Claims (5)

  A toner containing at least a binder resin and a colorant, and an external additive, the external additive having at least an average primary particle size Da of 80 to 300 nm and amorphous inorganic fine particles A toner having (A) and an average primary particle diameter Db of 80 to 300 nm and containing two types of crystalline inorganic fine particles (B).   The toner according to claim 1, wherein the inorganic fine particles (A) are silica, titania or alumina.   The toner according to claim 1, wherein the inorganic fine particles (B) are strontium titanate.   The relationship between the liberation ratio (volume%) Sa and Sb of the inorganic fine particles (A) and (B) with respect to the toner base particles is 0.1 <Sa ≦ 20 and 20 <Sb ≦ 50. Item 4. The toner according to any one of Items 1 to 3. A charging step of charging the electrostatic latent image carrier, an electrostatic latent image forming step of forming an electrostatic latent image on the charged electrostatic latent image carrier, and developing the electrostatic latent image with a developer; At the same time as the toner image is formed on the electrostatic latent image carrier, the simultaneous development process for collecting the toner remaining on the electrostatic latent image carrier after the transfer and the toner image on the electrostatic latent image carrier are intermediate In an image forming method having at least a transfer step of transferring to a transfer body or transfer material,
The image forming method according to claim 1, wherein the toner is the toner according to claim 1.

Images