JP2005164647A - Developer - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a developer having excellent low temperature fixing property of toner, offset resistance and blocking resistance, and capable of realizing a high-quality image without fog without causing carrier sticking or toner scattering. <P>SOLUTION: The developer contains the following toner and carrier. The toner contains: a binder resin containing an amorphous resin and a crystalline resin; and copolymer particles obtained by polymerizing monomers containing 99 to 80 wt.% radical polymerizable monomers and 1 to 20 wt.% sulfonic acid-based monomers and having 0.01 to 2 μm average particle size of primary particles. The carrier has the electric resistance R (Ω cm) of 12 to 25 in terms of common logarithm (LogR), 63 to 75 sec/(50×cm<SP>3</SP>) F1 defined by F1=AD×FR(1), and 30 to 100 Oe×g/cm<SP>3</SP>F2 defined by F2=AD×Hc(2), wherein AD represents apparent density, FR represents fluidity and Hc represents coercive force. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a developer used for developing an electrostatic latent image in image formation by electrophotography, electrostatic recording method, electrostatic printing method or the like.

  The electrophotographic method used in image forming apparatuses such as laser printers and dry electrostatic copying machines exposes the charged photoconductive insulating layer by exposing it to a charging process for uniformly charging the photoconductive insulating layer. The electric charge of the formed portion is dissipated to form an electric latent image, that is, an electrostatic latent image, and a developer is supplied to the formed electrostatic latent image, and a charge called toner in the developer A developing step for making the electrostatic latent image visible by attaching a colored fine powder having a toner, and a transfer step for transferring the obtained toner image, which is a visible image, to a transfer material such as recording paper; A fixing step in which the transferred toner image is permanently fixed to the transfer material by heating, pressing, or other appropriate fixing method.

  In the fixing step, a contact type heat fixing method using a heating roller or the like, or a non-contact type heat fixing method using an oven or the like is used. The contact-type heat fixing method is characterized by high thermal efficiency, and the temperature required for fixing can be lowered as compared with the non-contact type heat-fixing method. It is valid. However, the contact-type heat fixing method has a problem in that so-called offset development is likely to occur, in which part of the toner melted at the time of fixing is transferred to a heating roller and transferred to a subsequent recording paper or the like.

  Conventional techniques for preventing this offset phenomenon include processing the surface of the heating roller with a material with excellent releasability, such as fluorine resin, and applying a release agent such as silicone oil to the surface of the heating roller. Things are done. However, the use of these techniques is not preferable because the fixing device becomes large and complicated, the cost increases, and the failure easily occurs.

  For this reason, it is required that the toner does not cause an offset phenomenon and has excellent offset resistance. In addition, the toner is required to have a low temperature necessary for fixing and excellent low-temperature fixability from the viewpoint of energy saving of the image forming apparatus. Further, in the image forming apparatus, toner is stored inside the developing device, and only a necessary amount is used at the time of development. Therefore, the toner is stored inside the developing device for a long period of time. If blocking occurs, which is a state in which toner aggregates and hardens in the developing device, a sufficient amount of toner cannot be supplied to the electrostatic latent image, resulting in deterioration of the image. Therefore, the toner is also required to have high blocking resistance and excellent storage stability.

  Generally, toner obtained by pulverizing a binder resin in which a colorant or the like is dispersed is used. As a technique for improving the offset resistance of the toner, a method of adding paraffin wax, low molecular weight polyolefin or the like as an anti-offset agent to the toner is known. However, these anti-offset agents are not effective when added in a small amount, and conversely when they are too much, there is a problem that the deterioration of the developer is accelerated. In addition, when adding wax to the toner, if the wax is mixed strongly to uniformly disperse it in the binder resin, the polymer chain of the resin may be cleaved, and the wax may be removed while maintaining the physical properties of the resin. It is not easy to uniformly disperse in the binder resin.

  Therefore, attempts have been made to improve the offset resistance by using a specific resin for the binder resin of the toner. As such a toner, for example, there is a toner using a vinyl resin typified by a styrene-acrylic copolymer. However, in an attempt to improve offset resistance in a toner using a vinyl-based resin, it is necessary to increase the softening point and cross-linking density of the resin, which increases the fixing temperature and sacrifices low-temperature fixability. Become. On the other hand, if importance is attached to low-temperature fixability, the offset resistance and blocking resistance are hindered.

  On the other hand, a polyester resin is used as a binder resin for toner having excellent low-temperature fixability. Toner using polyester resin is essentially good fixability and can be fixed well even in non-contact type fixing methods, but offset phenomenon is likely to occur, and it is used for contact type fixing methods using a heating roller. There is a problem that it is difficult to do. In order to improve the offset resistance, it has been proposed to use a polyester resin composed of a trivalent or higher polyvalent carboxylic acid. However, many toners using a polyester resin composed of a trivalent or higher polyvalent carboxylic acid still do not have sufficient offset resistance for actual use, and also have sufficient offset resistance for actual use. In addition to sacrificing the inherent low-temperature fixability of the polyester resin, there is a problem in that the pulverizability when making a toner is extremely poor.

  As described above, since there are problems with toners using vinyl resins and toners using polyester resins, both polyester resins with excellent fixability and vinyl resins with excellent offset resistance and blocking resistance are used. Attempts have been made to use the resin as a binder resin as follows. For example, it has been proposed to use a polyester resin and a styrene-acrylic resin in a mechanically mixed manner (see, for example, Patent Document 1), a polyester resin and a styrene-acrylic resin that are chemically combined, and the like. Yes. As a resin in which a polyester resin and a styrene-acrylic resin are chemically bonded, an unsaturated polyester resin, for example, a polyester resin having a methacryloyl group or an acryloyl group is copolymerized with a vinyl monomer (for example, Patent Document 2). And a copolymer obtained by copolymerizing a reactive polyester and a vinyl monomer in the presence of a polyester resin (for example, see Patent Document 3).

  However, polyester resins and vinyl resins such as styrene-acrylic resins are inherently poor in compatibility, so if they are simply mechanically mixed as in the technique described in Patent Document 1, etc., depending on the mixing ratio, The dispersibility of the internal additive such as resin and carbon black is deteriorated, the chargeability of the toner is not uniform, and a bad effect such as background smearing occurs in the formed image. In particular, as in the toner described in Patent Document 1, when the molecular weight of the vinyl resin and the molecular weight of the polyester resin are greatly different, there may be a difference in both melt viscosities. Since it is difficult to reduce the diameter, the dispersibility of the internal additive such as carbon black in the toner becomes very poor, and there is a problem that the image stability is largely lacking. Moreover, when using what made the reactive polyester polymerize the vinyl monomer like the technique of patent document 2 or 3, in order to prevent gelatinization of binder resin, between vinyl-type resin and polyester resin is used. There is also the problem that the composition is limited.

  As another technique, it has been proposed to use a mixture of two types of resins having different softening points as a binder resin (see, for example, Patent Document 4). In the technique described in Patent Document 4, although the low-temperature fixability is improved by increasing the proportion of the resin having a low softening point, there is a problem in blocking resistance. Further, by increasing the glass transition point of the resin having a low softening point, the blocking resistance is improved. However, even if the proportion of such a resin is increased, sufficient low-temperature fixability cannot be obtained.

  Thus, a toner satisfying all of the low-temperature fixing property, the offset resistance and the blocking resistance has not been obtained. Further, in order to meet the recent demands for speeding up, downsizing and energy saving of copying machines, toners are required to be further improved in low-temperature fixability and offset resistance.

  On the other hand, in response to the demand for higher image quality, it has been proposed to reduce the toner particle size. As the developer, a two-component developer composed of a toner and a carrier is generally used. The toner particles are charged by frictional charging with the carrier when being stirred and mixed with the carrier. In the two-component developer, the toner particles tend to have a reduced charging ability as the particle size is reduced. Therefore, in order to sufficiently charge the toner particles having a small particle size, the carrier particle size is reduced, It is necessary to increase the specific surface area. However, since the small particle size carrier has poor fluidity and hardly causes frictional charging with the toner, when the small particle size carrier is used, the rising of charging of the toner is deteriorated, causing problems such as toner scattering. In order to solve this problem, it has been proposed to increase the stirring strength when the toner and the carrier are stirred and mixed. However, increasing the stirring strength increases the load on the developer and causes the toner to adhere to the carrier surface. The so-called spent and peeling of the coating film covering the carrier are likely to occur. For this reason, deterioration of developer characteristics is promoted, and another problem that good developer characteristics cannot be maintained over a long period of time occurs.

  Further, due to recent demands for downsizing image forming apparatuses, it has been demanded to provide high-quality images over a long period of time with a small amount of developer. Further, along with the downsizing of the developing device corresponding to the downsizing of the main body of the apparatus, members such as a flow restricting plate may be sufficiently disposed in the developer agitating unit inside the developing device and the developer supplying unit to the developing sleeve. It has become difficult.

  For this reason, as the developer, in the stirring portion that frictionally charges the toner and the carrier, frictional charging occurs rapidly with a load that does not cause deterioration, and uniform and soft spikes are formed on the developing sleeve. What is formed is sought.

  In order to realize a developer that satisfies this requirement, it has been proposed to use a specific carrier. For example, it has been proposed to use a carrier having a saturation magnetization of 50 emu / g or less (see Patent Document 5). However, if a carrier having a low saturation magnetization such as the carrier described in Patent Document 5 is used, the carrier has insufficient adhesion to the magnet roller inside the developing sleeve, and the carrier adheres to the recording paper together with the toner. There arises a problem that adhesion occurs and the image density decreases.

  In addition, it has been proposed to use so-called hard ferrite having a coercive force of 300 gauss or more as a carrier (see Patent Document 6). However, in order to use hard ferrite having a high coercive force, it is preferable that the device, particularly the magnet roller and the developing sleeve, have a special structure, which is not suitable for downsizing the device. Further, since hard ferrite has a high coercive force as described above, it has the disadvantages that it easily aggregates and has poor transportability. For this reason, in a developer using hard ferrite as a carrier, the toner and the carrier are not sufficiently agitated, and prompt frictional charging cannot be obtained, which causes problems such as toner scattering.

In another technique, it has been proposed to control the magnetization intensity and the rise of the magnetization intensity in a carrier magnetic field of 1000 oersted (see Patent Document 7). However, even if the carrier described in Patent Document 7 is used, the adhesion force of the carrier to the magnet roller cannot be improved, and the carrier adhesion to the recording paper cannot be suppressed. In addition, since the carrier described in Patent Document 7 has a weak magnetization strength of 30 to 150 emu / cm ³ in a magnetic field of 1000 oersted, the magnetic brush ears formed by the continuous carrier are short, and the magnetic brush is used as a developing sleeve. It is difficult to form across the magnetic poles. For this reason, when an electrostatic latent image is developed by bringing the magnetic brush into contact with the photoconductor, the magnetic brush ears are not soft enough and the pressing force of the magnetic brush against the photoconductor increases, so that the carrier adhesion Cannot be sufficiently suppressed, and a high-quality image cannot be realized.

  Further, in the techniques described in Patent Documents 5, 6 and 7, only the characteristics of the carrier are defined, and the characteristics of the toner are not taken into consideration, so that it is not possible to realize a developer that sufficiently satisfies the above-described requirements. . That is, in order to realize a developer that satisfies the above-described requirements, it is necessary to consider the combination of the carrier and the toner and the characteristics of the developer itself that is a combination thereof.

  For example, in order to improve the transportability of the developer, a developer in which the flowability of the developer is controlled to a certain level has been proposed (see Patent Document 8). Although the technique described in Patent Document 8 defines the flow rate per unit weight of the developer, in an actual apparatus, the developer flows in a predetermined volume. Even if it is controlled within the range described in Patent Document 8, a sufficient effect cannot be obtained. In the technique described in Patent Document 8, the residual magnetization with respect to the applied magnetic field of 3000 Oersted of the carrier is defined as 10 emu / g or less and the coercive force is defined as 40 Oersted or less. However, the residual magnetization and coercive force of the carrier are low. If it is too high, the carrier chain on the magnetic brush tends to be sparse, sufficient developing ability cannot be obtained, and it becomes difficult to control the fluidity of the developer on the magnetic brush, resulting in high image quality over a long period of time. Is difficult to hold.

  In another technique, in a developer using a toner containing a specific resin and a negative charge control agent and a carrier coated with a silicone resin, the fluidity of the carrier core material is prevented in order to prevent carrier adhesion and the edge effect. It is proposed to control the apparent density and cover the carrier core material with a non-uniform coating film (see Patent Document 9). However, when the carrier core material described in Patent Document 9 is used, the fluidity of the developer in the developing machine is deteriorated, the toner and the carrier are not sufficiently stirred, and an appropriate charge amount cannot be obtained. There is a problem that fogging and toner scattering occur in the image. This problem is particularly noticeable with small devices.

  Also, for the purpose of obtaining a developer capable of realizing a clear image with good environmental stability and no fogging, a specific toner obtained by suspension polymerization and a carrier having specific magnetic properties are combined. Has been proposed (see Patent Document 10). Although the developer described in Patent Document 10 has some effect on carrier adhesion, it cannot fully satisfy the recent demands for reducing carrier adhesion and improving image quality. Further, the occurrence of fogging and toner scattering cannot be sufficiently suppressed because the fluidity of the carrier in the stirring portion where the toner and the carrier are stirred is not appropriate.

JP-A-2-161464 Japanese Patent Laid-Open No. 2-5073 (page 3-5) JP-A-2-29664 JP-A-4-362956 JP 59-104663 A Japanese Patent Publication No. 4-3868 Japanese Patent No. 3005120 JP-A-6-332237 JP-A-7-175264 JP-A-7-175265

  The object of the present invention is to combine a specific toner and a specific carrier, so that the toner has excellent low-temperature fixing property, anti-offset property and anti-blocking property, and is free of carrier adhesion and toner scattering and high quality without fogging. It is an object to provide a developer capable of realizing the image.

The present invention is a developer comprising a toner and a carrier,
The toner is
(A) a binder resin including an amorphous resin and a crystalline resin;
(B) Copolymer particles obtained by polymerizing a monomer containing 99 to 80% by weight of a radical polymerizable monomer and 1 to 20% by weight of a sulfonic acid monomer, Copolymer particles having an average particle diameter of 0.01 μm or more and 2 μm or less,
The carrier is
The electrical resistivity R (Ω · cm) is 12 to 25 in common logarithm (LogR),
The first fluidity index F1 represented by the following formula (1) is 63 sec / (50 · cm ³ ) or more and 75 sec / (50 · cm ³ ) or less,
The second fluidity index F2 represented by the following formula (2) is 30 Oe · g / cm ³ or more and 100 Oe · g / cm ³ or less.
F1 = AD × FR (1)
F2 = AD × Hc (2)
Where AD: apparent density (g / cm ³ ),
FR: fluidity (sec / 50 g),
Hc: Coercive force (Oe) when a magnetic field of 3000 Oe is applied

  In the present invention, the crystalline resin has a softening point of 80 ° C. or higher and 150 ° C. or lower.

In the present invention, the amorphous resin includes a resin (resin A) having a softening point of 120 ° C. or higher and 170 ° C. or lower and a resin (resin B) having a softening point of 90 ° C. or higher and 120 ° C. or lower,
The crystalline resin has a melting point of 60 ° C. or higher and 140 ° C. or lower.

The present invention, the ratio of the weight _{W B} of the resin B and the weight _{W A} of the resin A _(W A / _{W B)} is characterized in that it is 100/70 or 100/10 or less.

In the present invention, the ratio (W _A / (W _B + W) of the weight W _{A of the} resin A and the sum (W _B + W _C ) of the weight W _B of the resin _B and the weight W _C of the crystalline resin is used. _C )) is 100/110 or more and 100/20 or less,
The ratio (W _B / W _C ) between the weight _B B of the resin B and the weight W _C of the crystalline resin is not less than 1/1 and not more than 4/1.

  In the invention, it is preferable that the amorphous resin and / or the crystalline resin is a polyester resin.

  The present invention is also characterized in that the crystalline resin is a crystalline polyester resin obtained by condensation polymerization of a monomer containing a diaryl compound in an amount of 0.1 mol% to 20 mol%.

  In the present invention, the diaryl compound is a diol compound having a bisphenol A skeleton.

  In the present invention, the crystalline polyester resin may be obtained by polycondensing a monomer other than a diaryl compound by 50% or more, then adding a diaryl compound to the reaction system, and further performing polycondensation. Features.

  In the invention, it is preferable that the amorphous resin is obtained by condensation polymerization of a monomer containing 40 mol% or more of a diaryl compound.

  The present invention is also characterized in that the dispersed particle diameter of the crystalline resin in the toner is 0.05 μm or more and 0.20 μm or less.

According to the present invention, the toner further contains a wax,
The ratio of the weight _{W C} of the crystalline resin and the weight _{W W} of the wax _(W C / _{W W)} is characterized by is 1/1 or 4/1 or less.

In the present invention, the radical polymerizable monomer is a styrene monomer and / or an acrylic monomer,
The sulfonic acid monomer is 2-acrylamido-2-methylpropanesulfonic acid.

  Further, the present invention is characterized in that the copolymer particles are obtained by emulsion polymerization of a monomer containing a radical polymerizable monomer and a sulfonic acid monomer.

  Further, the present invention is characterized in that the copolymer particles are obtained by separately dropping a radical polymerizable monomer and a sulfonic acid monomer into a polymerization system.

  In the invention, it is preferable that the carrier has a weight average particle diameter Dw of 30 μm or more and 120 μm or less.

  According to the present invention, the carrier has a coercive force Hc of 12 Oe or more and 60 Oe or less when a magnetic field of 3000 Oe is applied.

  In the invention, the carrier has a saturation magnetization of 20 emu / g or more and 45 emu / g or less when a magnetic field of 3000 Oe is applied.

In the present invention, the carrier may be
Including a carrier core and a coating layer covering the carrier core;
The weight of the coating layer is 0.8 parts by weight or more and 15 parts by weight or less with respect to 100 parts by weight of the carrier core material.

In the present invention, the carrier may be
Including a carrier core and a coating layer covering the carrier core;
The carrier core material is ferrite.

According to the present invention, the developer includes a toner and a carrier. The toner is obtained by polymerizing a binder resin including an amorphous resin and a crystalline resin, and a monomer including a radical polymerizable monomer 99 to 80% by weight and a sulfonic acid monomer 1 to 20% by weight. Copolymer particles having an average primary particle size of 0.01 μm or more and 2 μm or less, and the copolymer particles function as a negative charge control agent. . The carrier has an electrical resistivity R (Ω · cm) of 12 or more and 25 or less in the common logarithm value (LogR), and the first fluidity index F1 represented by the formula (1) is 63 sec / (50 · cm ³ ). It is 75 sec / (50 · cm ³ ) or less, and the second fluidity index F2 represented by the formula (2) is 30 Oe · g / cm ³ or more and 100 Oe · g / cm ³ or less. By using a combination of an amorphous resin and a crystalline resin as the binder resin for the toner, a toner having excellent low-temperature fixability, offset resistance, and blocking resistance can be obtained. By using the copolymer particles as a negative charge control agent in such a toner and using it in combination with the carrier, carrier adhesion and toner scattering are suppressed, and a high-quality image is realized. Therefore, by combining the specific toner and the specific carrier as described above, the toner has excellent low-temperature fixability, anti-offset property and anti-blocking property, and is free from carrier adhesion and toner scattering, and is free from fogging. A developer capable of realizing the above can be obtained.

  Further, according to the present invention, since the softening point of the crystalline resin is 80 ° C. or higher and 150 ° C. or lower, the low-temperature fixing property, offset resistance and blocking resistance of the toner are further improved.

  According to the present invention, the amorphous resin includes a resin A having a softening point of 120 ° C. or higher and 170 ° C. or lower and a resin B having a softening point of 90 ° C. or higher and 120 ° C. or lower, and the melting point of the crystalline resin. Is from 60 ° C. to 140 ° C., the crystalline resin is uniformly dispersed in the toner. Accordingly, a toner that exhibits the characteristics of the crystalline resin sufficiently and is particularly excellent in low-temperature fixability, offset resistance, and blocking resistance is realized. Further, the spread of the toner charge amount distribution and the decrease in the coloring degree can be suppressed.

According to the invention, the ratio of the weight _{W B} of the weight of the resin A _{W A} and the resin _{B (W} A / W B) is a 100/70 or 100/10 or less, the low temperature fixability of the toner, resistance Offset property and blocking resistance are further improved.

Further, according to the present invention, the ratio (W _A / (W _B + W _C ) of the weight W _A of the resin _A and the sum (W _B + W _C ) of the weight W _B of the resin _B and the weight W _C of the crystalline resin. )) Is 100/110 or more and 100/20 or less, and the ratio of W _B to W _C (W _B / W _C ) is 1/1 or more and 4/1 or less. Properties and blocking resistance are further improved.

  According to the present invention, since the amorphous resin and / or the crystalline resin is a polyester resin, it is excellent in low-temperature fixability, offset resistance, and blocking resistance, and is excellent in durability and dispersibility of the colorant. Toner is realized.

  According to the invention, the crystalline resin is a crystalline polyester resin obtained by condensation polymerization of a monomer containing a diaryl compound, preferably a diol compound having a bisphenol A skeleton, in an amount of 0.1 mol% to 20 mol%. Therefore, it is dispersed in a good dispersion state in the toner. Therefore, the low-temperature fixability, offset resistance and blocking resistance of the toner are further improved.

  Further, according to the present invention, the crystalline polyester resin is obtained by condensation polymerization of a monomer other than the diaryl compound by 50% or more and then adding the diaryl compound to the reaction system and further condensation polymerization. The effect of the diaryl compound on the thermal properties such as the softening point and melting point of the crystalline polyester resin is small. Therefore, the dispersibility of the crystalline polyester resin in the toner can be improved while maintaining the effect of improving the low-temperature fixability, offset resistance and blocking resistance of the toner, and the crystalline polyester resin has sufficient characteristics. To further improve the low-temperature fixability, offset resistance and blocking resistance.

  According to the invention, the amorphous resin is obtained by condensation polymerization of a monomer containing 40 mol% or more of a diaryl compound, and therefore contains 0.1 mol% or more and 20 mol% or less of a diaryl compound. The crystalline polyester resin obtained by condensation polymerization of the monomer is uniformly dispersed in the toner. Therefore, a toner that exhibits the characteristics of the crystalline polyester resin sufficiently and is particularly excellent in low-temperature fixability, offset resistance, and blocking resistance is realized. Further, the spread of the toner charge amount distribution and the decrease in the coloring degree can be suppressed.

  According to the invention, the crystalline resin has a dispersed particle size in the toner of 0.05 μm or more and 0.20 μm or less, and is uniformly dispersed in the toner. Accordingly, a toner that exhibits the characteristics of the crystalline resin sufficiently and is particularly excellent in low-temperature fixability, offset resistance, and blocking resistance is realized. Further, the spread of the toner charge amount distribution and the decrease in the coloring degree can be suppressed.

According to the invention, the toner contains a wax. Since the ratio of the weight _{W C} and weight _{W W} of the wax of the crystalline resin _(W C / _{W W)} is a 1/1 or 4/1 or less, the wax is dispersed in a good dispersion state in the toner. Therefore, a toner that is particularly excellent in low-temperature fixability, offset resistance, blocking resistance, and fluidity is realized.

  Further, according to the present invention, a styrene monomer and / or an acrylic monomer is used as the radical polymerizable monomer, and 2-acrylamido-2-methylpropanesulfonic acid is used as the sulfonic acid monomer. Therefore, it is possible to easily obtain copolymer particles having softness that is preferable as a component of the toner.

  In addition, according to the present invention, by emulsion polymerization of a monomer containing a radical polymerizable monomer and a sulfonic acid monomer, the average particle diameter of the primary particles is 0.01 μm or more and 2 μm or less. The copolymer particles having a large molecular weight and a high concentration of sulfonic acid groups on the surface can be obtained. By using such copolymer particles, the copolymer particles are uniformly dispersed in a particle state in the binder resin, and the characteristics of the copolymer particles are sufficiently exhibited. Stability, particularly the rising characteristics of charging at high temperature and high humidity, is further improved.

  According to the present invention, the reactivity of the radical polymerizable monomer and the sulfonic acid monomer can be increased by dropping the radical polymerizable monomer and the sulfonic acid monomer separately into the polymerization system. Since it can improve, the said copolymer particle can be obtained easily.

  According to the present invention, since the weight average particle diameter Dw of the carrier is 30 μm or more and 120 μm or less, the decrease in magnetization per carrier particle is suppressed, the carrier adhesion is further suppressed, and the charging ability of the carrier is decreased. And a sufficient charge amount is imparted to the toner. Therefore, it is possible to obtain a developer capable of realizing a particularly high quality image.

  According to the invention, the coercive force Hc of the carrier is 12 Oe or more and 60 Oe or less. As a result, the carrier chain can be formed densely on the developing sleeve. In addition, since the fluidity of the developer on the developing sleeve can be improved, the toner can be sufficiently supplied to the electrostatic latent image. Further, since the carrier chain tends to be separated after being separated from the developing sleeve, the carrier and newly supplied toner are easily mixed. Accordingly, it is possible to obtain a developer that is particularly excellent in development characteristics.

  Further, according to the present invention, since the saturation magnetization of the carrier is 20 emu / g or more and 45 emu / g or less, the carrier adhesion is further suppressed and the ears of the magnetic brush formed on the developing sleeve are made moderately soft. Higher quality images are realized.

  According to the invention, the carrier includes a carrier core material and a coating layer, and the weight of the coating layer is 0.8 parts by weight or more and 15 parts by weight or less with respect to 100 parts by weight of the carrier core material. Carriers having the resistivity R, the first fluidity index F1, and the second fluidity index F2 in the above ranges can be easily obtained. Further, peeling of the coating layer can be suppressed and good development characteristics can be maintained.

  According to the present invention, since the carrier includes a carrier core material made of ferrite and a coating layer, a carrier having the electrical resistivity R, the first fluidity index F1, and the second fluidity index F2 within the above ranges is easy. To be realized.

  A developer according to an embodiment of the present invention includes a toner and a carrier, and is used for developing an electrostatic latent image in image formation by, for example, electrophotography, electrostatic recording, or electrostatic printing.

  The toner includes toner particles containing a binder resin, a colorant, and a negative charge control agent, and is used by being negatively charged by frictional charging with a carrier.

  As the binder resin, an amorphous resin and a crystalline resin are used in combination. Here, the amorphous resin is a resin in which a clear melting peak does not appear in a DSC curve measured by a differential scanning calorimeter (hereinafter sometimes abbreviated as DSC). It is a resin in which a clear melting peak appears in the DSC curve. By using a combination of an amorphous resin and a crystalline resin, a toner having excellent low-temperature fixability, offset resistance and blocking resistance, that is, storage stability is realized.

  The crystalline resin is used in a state of being dispersed in toner particles. If the dispersibility of the crystalline resin is not good, the characteristics of the crystalline resin cannot be fully exerted, so that the toner cannot sufficiently obtain low-temperature fixability, offset resistance and blocking resistance (storage stability), and charging. This is not preferable because the amount distribution is widened and the coloring degree is also lowered. When the crystalline resin is dispersed in the toner particles, the crystalline resin having poor dispersibility has a large particle diameter because the primary particles aggregate to form secondary particles. Therefore, the dispersibility of the crystalline resin can be represented by the particle diameter of the crystalline resin in a state dispersed in the toner, that is, the dispersed particle diameter of the crystalline resin in the toner. The dispersed particle diameter of the crystalline resin in the toner is preferably 0.05 μm or more and 0.20 μm or less, and more preferably 0.07 μm or more and 0.13 μm or less. A crystalline resin having a dispersed particle size in the toner in the above range is in a state of primary particles in the toner and is uniformly dispersed in the toner.

  The dispersed particle diameter of the crystalline resin in the toner can be determined as follows. First, a cross-sectional TEM photograph of the toner is taken using a transmission electron microscope (TEM). The obtained cross-sectional TEM photograph is analyzed with an image processing apparatus (manufactured by Nireco Co., Ltd.), and the length of the long axis of the crystalline resin particles contained in the toner is measured. This measurement is performed on 50 crystalline resin particles contained in the toner, and the average value of the length of the major axis is obtained from the measurement result, and this is used as the dispersed particle diameter.

  The physical properties of the amorphous resin are selected as follows in order to realize a toner having excellent low-temperature fixability, offset resistance, blocking resistance and durability.

  The softening point Tm of the amorphous resin is preferably 70 ° C. or higher and 180 ° C. or lower, more preferably 90 ° C. or higher and 160 ° C. or lower.

  The glass transition point Tg of the amorphous resin is preferably 45 ° C. or higher and 80 ° C. or lower, more preferably 55 ° C. or higher and 75 ° C. or lower. Glass transition is a physical property peculiar to an amorphous part of an amorphous resin and a crystalline resin, and is distinguished from melting.

  The amorphous resin may include a resin component that does not dissolve in chloroform, or may not include a resin component that does not dissolve in chloroform, that is, a resin having a chloroform insoluble fraction of 0% by weight. When the amorphous resin contains a resin component that does not dissolve in chloroform, the chloroform insoluble fraction is preferably 50% by weight or less, more preferably 15% by weight or more and 35% by weight or less.

  Here, the chloroform-insoluble fraction is a weight fraction of a resin component that does not dissolve in chloroform, and is an index indicating the crosslinkability of the resin. Since the cross-linking component (non-linear component) of the resin is difficult to dissolve in the solvent, gelation occurs when an attempt is made to dissolve the resin having a large amount of cross-linking component in the solvent. That is, the higher the chloroform-insoluble fraction, the more cross-linking components are included. Since the resin has higher elasticity as it contains more crosslinking components, offset resistance and durability are improved by using a resin having a high chloroform-insoluble fraction. However, since a resin containing a large amount of cross-linking components cannot be melted quickly at a low temperature, the low-temperature fixability is lowered. Therefore, the chloroform-insoluble fraction such as the amorphous resin used for the binder resin is selected so that all of the offset resistance, durability and low-temperature fixability are good. In addition, the value of the chloroform insoluble fraction in the present specification is a value measured by a measurement method described later at a temperature of 25 ° C.

  The physical properties of the crystalline resin are selected as follows in order to realize a toner having excellent low-temperature fixability, offset resistance, blocking resistance and durability.

  The softening point Tm of the crystalline resin is preferably 80 ° C. or higher and 150 ° C. or lower, more preferably 90 ° C. or higher and 150 ° C. or lower, and particularly preferably 95 ° C. or higher and 145 ° C. or lower. The melting point of the crystalline resin is preferably 60 ° C. or higher and 150 ° C. or lower, more preferably 70 ° C. or higher and 140 ° C. or lower, and particularly preferably 80 ° C. or higher and 130 ° C. or lower.

  It is preferable that the crystalline resin does not contain a resin component that does not dissolve in chloroform, that is, the chloroform insoluble fraction is 0% by weight.

  As the binder resin, it is preferable to use a combination of two or more kinds of amorphous resins having different softening points and one or more kinds of crystalline resins. Specifically, as an amorphous resin, a resin having a softening point of 120 ° C. or higher and 170 ° C. or lower (hereinafter referred to as resin A) and a resin having a softening point of 90 ° C. or higher and 120 ° C. or lower (hereinafter referred to as resin B). The resin having a melting point of 60 ° C. or higher and 140 ° C. or lower (hereinafter referred to as crystalline resin C) is preferably used as the crystalline resin.

  The crystalline resin and the amorphous resin having a softening point far away from the melting point of the crystalline resin have greatly different melt viscosities at the same temperature. Therefore, the amorphous resin and the crystalline resin are melt-kneaded to form a toner. However, it is difficult to uniformly disperse the crystalline resin in the toner particles. On the other hand, as described above, the crystalline resin and at least two kinds of amorphous resins having different softening points, that is, a high softening point resin having a softening point far from the melting point of the crystalline resin, When a low softening point resin having a softening point close to the melting point of the resin is used in combination, when the amorphous resin and the crystalline resin are melt-kneaded, the low softening point resin and the high softening point resin are crystallized. The crystalline resin is uniformly dispersed in the toner particles. Accordingly, a toner that exhibits the characteristics of the crystalline resin sufficiently and is particularly excellent in low-temperature fixability, offset resistance, and blocking resistance is realized. Further, the spread of the toner charge amount distribution and the decrease in the coloring degree can be suppressed.

  Resin A, resin B, and crystalline resin C have physical properties and compounding ratios that fully exhibit the excellent properties of each resin, and are excellent in all of low-temperature fixability, offset resistance, blocking resistance, and durability. Is selected as follows.

  The softening point Tm (hereinafter referred to as Tm (A)) of the resin A is preferably 120 ° C. or higher from the viewpoint of offset resistance and durability, and 170 ° C. or lower from the viewpoint of low-temperature fixability. Preferably, it is 130 degreeC or more and 165 degreeC or less. The glass transition point Tg (hereinafter referred to as Tg (A)) of the resin A is preferably 58 ° C. or higher from the viewpoint of blocking resistance, and preferably 75 ° C. or lower from the viewpoint of low-temperature fixability. More preferably, it is 58 degreeC or more and 70 degrees C or less. The chloroform-insoluble fraction of the resin A is preferably 10% by weight or more from the viewpoint of offset resistance and durability, preferably 30% by weight or less from the viewpoint of low-temperature fixability, and more preferably 10% by weight. As mentioned above, it is 25 weight% or less.

  The physical properties of the resin B are particularly selected so as to enhance the compatibility between the resin A and the crystalline resin C. The softening point Tm (hereinafter referred to as Tm (B)) of the resin B is preferably 90 ° C. or higher and 120 ° C. or lower as described above, more preferably 90 ° C. or higher and 110 ° C. or lower, and further the resin A It is preferably 20 ° C. or more lower than the softening point Tm (A).

  The glass transition point Tg (hereinafter referred to as Tg (B)) of the resin B is preferably 50 ° C. or higher and 75 ° C. or lower, more preferably 58 ° C. or higher and 70 ° C. or lower. Resin B may or may not contain a resin component that does not dissolve in chloroform. When the resin B contains a resin component that does not dissolve in chloroform, the chloroform-insoluble fraction of the resin B is preferably 30% by weight or less, and more preferably 25% by weight or less.

  As described above, the melting point of the crystalline resin C is preferably 60 ° C. or higher and 140 ° C. or lower, more preferably 80 ° C. or higher and 140 ° C. or lower, and particularly preferably 80 ° C. or higher and 130 ° C. or lower.

  It is preferable that the crystalline resin C does not contain a resin component that does not dissolve in chloroform, that is, the chloroform insoluble fraction is 0% by weight.

The ratio of the weight _{W B} of the weight _{W A} and the resin B of the resin A in the toner _(W A / _{W B)} is preferably 100/70 or 100/10 or less, more preferably 100/55 to 100 / 10 or less, more preferably 100/30 or more and 100/10 or less.

Further, the weight _{W A} of the resin A in the toner, the sum of the weight _{W B} of the resin B and the weight _{W C} of the crystalline resin _{C (W} B + W C) and the ratio of _{(W A / (W B +} W C) ) Is preferably 100/110 or more and 100/20 or less, more preferably 100/80 or more and 100/30 or less, and still more preferably 100/70 or more and 100/40 or less.

The ratio of the weight _{W B} of the resin B in the toner and the weight _{W C} of the crystalline resin _{C (W} B / W C) is preferably 1/1 or 4/1 or less, more preferably 1 / 1 to 3/1.

  The resin A, the resin B, and the crystalline resin C may each be one type of resin, or may be a resin composition in which two or more types of resins are mixed.

  As a crystalline resin such as the crystalline resin C, a crystalline polyester resin is preferably used. By using the crystalline polyester resin, it is possible to realize a toner that is excellent in low-temperature fixability, offset resistance, and blocking resistance, as well as in durability and colorant dispersibility.

  The crystalline polyester resin is obtained by polycondensing a monomer containing an alcohol component composed of a divalent or higher valent hydroxy compound and a carboxylic acid component composed of a divalent or higher carboxylic acid compound. Here, the divalent or higher-valent hydroxy compound is a compound having two or more hydroxyl groups, and includes both alcohols and phenols. The divalent or higher carboxylic acid compound is a polyvalent carboxylic acid which is a compound having two or more carboxyl groups, and a derivative such as an anhydride or ester of a polyvalent carboxylic acid.

  The crystalline polyester resin has a diaryl compound content of 0.1 mol% or more and 20 mol% or less, preferably 0.5 mol% or more and 17 mol% or less, more preferably 1 mol% or more and 10 mol% in the total amount of monomers. % Or less is preferable. Here, the diaryl compound is a compound having two aromatic functional groups, and the aromatic functional group is a functional group showing aromaticity such as a benzene ring, a naphthalene ring, and a pyridine ring. . For example, 2,2-bis (4-hydroxyphenyl) propane called diphenyl, binaphthyl and bisphenol A is a diaryl compound having two aromatic functional groups, such as phenol, toluene, xylene, terephthalic acid and isophthalic acid. An acid or the like is a compound having one aromatic functional group.

  A crystalline polyester resin obtained by polycondensing a monomer containing 0.1 to 20 mol% of a diaryl compound is a resin obtained by polycondensing a monomer containing 40 or more mol% of a diaryl compound. It has a skeleton that is somewhat different from the skeleton.

  In general, although crystalline polyester resin and amorphous resin have low compatibility, if the skeleton of crystalline polyester is similar to the skeleton of amorphous resin, they are compatible and the crystalline polyester resin It becomes difficult to exhibit the characteristics. On the other hand, if the skeleton of the crystalline polyester resin and the skeleton of the amorphous resin are somewhat different, the crystalline polyester resin and the amorphous resin are appropriately compatible, and the crystalline polyester resin is amorphous. Since it is appropriately dispersed in the resin, the characteristics of the crystalline polyester resin are sufficiently exhibited.

  That is, it is obtained by polycondensing a crystalline polyester resin obtained by polycondensing a monomer containing 0.1 to 20 mol% of a diaryl compound, and a monomer containing 40 mol% or more of a diaryl compound. By using the binder resin in combination with the amorphous resin, the crystalline polyester resin can be uniformly dispersed in the toner particles. Therefore, a toner that exhibits the characteristics of the crystalline polyester resin sufficiently and is particularly excellent in low-temperature fixability, offset resistance, and blocking resistance is realized.

  In particular, an amorphous resin obtained by condensation polymerization of a monomer containing 40 mol% or more of a diaryl compound is used as the resin A and the resin B described above, and 0.1 mol% of a diaryl compound is used as the crystalline resin C. By using a crystalline polyester resin obtained by condensation polymerization of a monomer containing 20 mol% or less, the dispersibility of the crystalline polyester resin in the toner particles can be further improved. Properties and blocking resistance are further improved.

  As the diaryl compound used as the alcohol component, a diol compound having a bisphenol A or bisphenol A skeleton is preferably used. Here, the bisphenol A skeleton is a structure in which hydrogen atoms of two hydroxyl groups are removed from bisphenol A. Of the diol compounds having a bisphenol A skeleton, a diol compound represented by the following general formula (I) is particularly preferably used.

In the general formula (I), R ¹ represents an alkylene group having 2 or 3 carbon atoms, and x and y each represents an integer of 0 to 16 that satisfies the relationship of 1 ≦ x + y ≦ 16. The average value of the sum of x and y (x + y) is preferably 1.5 or more and 5.0 or less.

  Specific examples of the diol compound represented by the general formula (I) include polyoxypropylene (2.2) -2,2-bis (4-hydroxyphenyl) propane, polyoxyethylene (2.2) -2, Examples include alkylene oxide adducts of bisphenol A such as 2-bis (4-hydroxyphenyl) propane. In addition, the numerical value shown in parentheses such as (2.2) after “polyoxypropylene”, “polyoxyethylene”, etc. is the average number of moles of alkylene oxide added relative to 1 mole of bisphenol A, and is represented by the general formula (I) Corresponds to the average value of the sum of x and y (x + y). For example, polyoxypropylene (2.2) -2,2-bis (4-hydroxyphenyl) propane is a compound in which an average of 2.2 mol of propylene oxide is added to 1 mol of bisphenol A.

  Examples of the diaryl compound used as the carboxylic acid component include diphenyl-4,4'-dicarboxylic acid and bis (4-carboxyphenyl) methane.

  In addition to the diaryl compound, examples of the compound used as the monomer of the crystalline polyester resin include the following compounds.

  As the alcohol component, it is preferable to use an aliphatic diol having 2 to 6 carbon atoms, preferably 4 to 6 carbon atoms. Examples of the aliphatic diol having 2 to 6 carbon atoms include 1,4-butanediol, ethylene glycol, 1,2-propylene glycol, 1,3-propylene glycol, 1,6-hexanediol, neopentyl glycol, 1,4 -Butenediol, 1,5-pentanediol, and the like, among which α, ω-linear alkyldiol is preferably used. These aliphatic diols may be used alone or in a combination of two or more. When a diaryl compound is not used for the alcohol component, the aliphatic diol having 2 to 6 carbon atoms is preferably contained in the alcohol component in an amount of 80 mol% or more, preferably 90 mol% or more and 100 mol% or less. In particular, it is preferable that one aliphatic diol in them accounts for 70 mol% or more, preferably 80 mol% or more of the alcohol component. When a diaryl compound is used for the alcohol component, the aliphatic diol having 2 to 6 carbon atoms may be contained in the alcohol component in an amount of 60 mol% or more, preferably 65 mol% or more and 99.8 mol% or less. In particular, it is preferable that one aliphatic diol in them accounts for 55 mol% or more, preferably 60 mol% or more of the alcohol component.

  Examples of divalent alcohol components other than aliphatic diols having 2 to 6 carbon atoms include diethylene glycol, triethylene glycol, 1,8-octanediol, 1,4-cyclohexanedimethanol, dipropylene glycol, polyethylene glycol, polypropylene glycol, Examples thereof include polytetramethylene glycol and hydrogenated bisphenol A.

  Examples of the trihydric or higher alcohol component include aromatic alcohols such as 1,3,5-trihydroxymethylbenzene, sorbitol, 1,2,3,6-hexanetetraol, pentaerythritol, dipentaerythritol, tripentaerythritol, Aliphatics such as 1,2,4-butanetriol, 1,2,5-pentanetriol, glycerin, 2-methylpropanetriol, 2-methyl-1,2,4-butanetriol, trimethylolethane and trimethylolpropane Examples include alcohols and alicyclic alcohols such as 1,4-sorbitan.

  As the carboxylic acid component, an aromatic dicarboxylic acid compound or an aliphatic dicarboxylic acid compound having 2 to 6, preferably 4 to 6 and particularly preferably 4 carbon atoms is suitably used. Examples of the aromatic dicarboxylic acid compound include phthalic acid, isophthalic acid and terephthalic acid, and anhydrides or alkyl (carbon number 1 to 3) esters of these acids. One of these aromatic dicarboxylic acid compounds may be used alone, or two or more thereof may be mixed and used.

  Examples of the aliphatic dicarboxylic acid compound having 2 to 6 carbon atoms include oxalic acid, malonic acid, maleic acid, fumaric acid, citraconic acid, itaconic acid, glutaconic acid, succinic acid and adipic acid, and anhydrides or alkyls of these acids. (C1-C3) ester etc. are mentioned. One of these aliphatic dicarboxylic acid compounds may be used alone, or two or more thereof may be mixed and used.

  In the carboxylic acid component, any one of the aromatic dicarboxylic acid compound and the aliphatic dicarboxylic acid compound having 2 to 6 carbon atoms is 80 mol% or more, preferably 90 mol% or more, preferably 100 mol% in total. In particular, it is preferable that one kind of aromatic dicarboxylic acid compound or aliphatic carboxylic acid compound occupies 70 mol% or more, preferably 80 mol% or more of the carboxylic acid component. When a diaryl compound is used for the carboxylic acid component, either one of the aromatic dicarboxylic acid compound and the aliphatic dicarboxylic acid compound having 2 to 6 carbon atoms is 60 mol% or more in total in the carboxylic acid component. Preferably, it is contained in an amount of 65 mol% or more and 99.8 mol% or less, and in particular, one aromatic dicarboxylic acid compound or aliphatic carboxylic acid compound is 55 mol% or more of the carboxylic acid component, preferably It is preferable to occupy 60 mol% or more.

  Examples of divalent carboxylic acid components other than aromatic dicarboxylic acid compounds and C2-C6 aliphatic dicarboxylic acid compounds include aliphatic carboxylic acids such as sebacic acid, azelaic acid, n-dodecyl succinic acid, and n-dodecenyl succinic acid And alicyclic carboxylic acids such as cyclohexanedicarboxylic acid, and anhydrides or alkyl (carbon number 1 to 3) esters of these acids.

  Examples of the trivalent or higher carboxylic acid component include 1,2,4-benzenetricarboxylic acid (common name: trimellitic acid), 2,5,7-naphthalenetricarboxylic acid, 1,2,4-naphthalenetricarboxylic acid, and 1, Aromatic carboxylic acids such as 2,4,5-benzenetetracarboxylic acid (common name: pyromellitic acid), 1,2,4-butanetricarboxylic acid, 1,2,5-hexanetricarboxylic acid, 1,3-di Fatty acids such as carboxyl-2-methyl-2-methylenecarboxypropane, tetra (methylenecarboxyl) methane and 1,2,7,8-octanetetracarboxylic acid, and 1,2,4-cyclohexanetricarboxylic acid Examples thereof include cyclic carboxylic acids, and anhydrides or alkyl (C1-C3) esters of these acids.

  For example, the crystalline polyester resin may be prepared by using a monomer containing the above-described alcohol component and carboxylic acid component in an inert gas atmosphere, if necessary, using an esterification catalyst such as dibutyltin oxide, a polymerization inhibitor, or the like. It is obtained by reacting at a temperature of 120 to 230 ° C. and performing condensation polymerization.

  In order to increase the strength of the resulting resin, it is preferable to add all the monomers to the reaction vessel in a batch and react, and in order to reduce the low molecular weight component, a divalent monomer, that is, a divalent monomer. After reacting the alcohol component with the divalent carboxylic acid component, it is preferable to add a trivalent or higher monomer to react. Further, the reaction may be promoted by reducing the pressure of the reaction system in the latter half of the polymerization reaction. However, in order to reduce the influence of the diaryl compound on the thermal properties such as the softening point and melting point of the crystalline polyester resin and maintain the effect of improving the low-temperature fixability, offset resistance and blocking resistance of the toner, It is preferable to subject the monomers other than the diaryl compound to 50% or more, more preferably 80% or more, and particularly preferably 90% or more, after condensation polymerization, and then add the diaryl compound to the reaction system to further perform condensation polymerization. In addition, the reaction rate of monomers other than a diaryl compound can be calculated | required from the ratio (molar ratio) of the distilled amount of the water from a reaction system with respect to the theoretical dehydration amount at the time of polycondensation.

  The weight average molecular weight (Mw) of the crystalline polyester resin is preferably 1000 or more and 20000 or less, and more preferably 2000 or more and 15000 or less. The number average molecular weight (Mn) is preferably 500 or more and 5500 or less. The ratio (Mw / Mn) of the weight average molecular weight (Mw) to the number average molecular weight (Mn) is preferably 2.0 or more and 15.0 or less, more preferably 2.0 or more and 12.5 or less. is there.

  The melt viscosity of the crystalline polyester resin is preferably 5 mPa · s or more and 1000 mPa · s or less, more preferably 5 mPa · s or more and 800 mPa · s or less at a temperature of 150 ° C. from the viewpoint of low-temperature fixability. 10 mPa · s or more and 500 mPa · s or less is optimal.

  The acid value of the crystalline polyester resin is preferably 3 mgKOH / g or more and 20 mgKOH / g or less, more preferably 3 mgKOH / g or more and 15 mgKOH / g or less, from the viewpoint of the stability of the chargeability of the toner. The hydroxyl value of the crystalline polyester resin is preferably from 0.5 mgKOH / g to 5 mgKOH / g, more preferably from 0.5 mgKOH / g to 4 mgKOH, from the viewpoint of environmental stability and storage stability of the toner. / G or less.

  Examples of amorphous resins such as Resin A and Resin B include amorphous polyester resins and amorphous polyester-polyamide resins. When these amorphous resins are used in combination with a crystalline polyester resin obtained by polycondensing a monomer containing 0.1 to 20 mol% of the above-mentioned diaryl compound, the diaryl compound Preferably, it is preferably obtained by condensation polymerization of a monomer containing an aromatic compound having a bisphenol A skeleton. In this amorphous resin, the proportion of the diaryl compound in the total amount of monomers is preferably 40 mol% or more, more preferably 45 mol% or more, as described above.

  Among the above-mentioned amorphous resins, amorphous polyester resins are preferably used from the viewpoint of fixability, durability, and dispersibility of the colorant. In particular, when a crystalline polyester resin is used as the crystalline resin, it is preferable to use an amorphous polyester resin from the viewpoint of compatibility with the crystalline polyester resin.

  Amorphous polyester resin, like the crystalline polyester resin described above, is a polycondensation of a monomer containing an alcohol component composed of a divalent or higher hydroxy compound and a carboxylic acid component composed of a divalent or higher carboxylic acid compound. Can be obtained. As described above, the amorphous polyester resin preferably contains 40% by mole or more, more preferably 45% by mole or more of the diaryl compound in all monomers.

  The diaryl compound is preferably contained in the alcohol component. The proportion of the diaryl compound in the alcohol component is preferably 80 mol% or more, more preferably 90 mol% or more, from the viewpoint of amorphization, durability and chargeability of the polyester resin. It is particularly preferred that the total amount is a diaryl compound.

  Examples of the diaryl compound used as the alcohol component include the aforementioned diol compounds having bisphenol A and a bisphenol A skeleton, for example, alkylene oxide adducts of bisphenol A such as the diol compounds represented by the general formula (I). As the alkylene oxide adduct of bisphenol A, an alkylene oxide having 2 or 3 carbon atoms added with an average addition mole number of 1 to 10 is preferable.

  Examples of the diaryl compound used as the carboxylic acid component include the aforementioned diphenyl-4,4′-dicarboxylic acid and bis (4-carboxyphenyl) methane.

  In addition to the diaryl compound, examples of the compound used as the monomer for the amorphous polyester resin include the following compounds.

  Examples of the divalent alcohol component include ethylene glycol, propylene glycol, neopentyl glycol, 1,6-hexanediol and hydrogenated bisphenol A, and an alkylene oxide having 2 or 3 carbon atoms added to these compounds with an average addition mole number of 1. And those added at 10 to 10.

  As trivalent or higher alcohol components, sorbitol, 1,4-sorbitan, pentaerythritol, glycerin and trimethylolpropane, and alkylene oxides having 2 or 3 carbon atoms were added to these compounds with an average addition mole number of 1 to 10. Things.

  Examples of the divalent carboxylic acid component include dicarboxylic acids such as phthalic acid, isophthalic acid, terephthalic acid, fumaric acid and maleic acid, alkyl groups having 1 to 20 carbon atoms such as dodecenyl succinic acid and octyl succinic acid, or 2 to 20 carbon atoms. And succinic acid substituted with an alkenyl group, and anhydrides or alkyl (carbon number 1 to 12) esters of these acids. Among these, maleic acid, fumaric acid, terephthalic acid, or succinic acid substituted with an alkenyl group having 2 to 20 carbon atoms is preferably used.

  The trivalent or higher carboxylic acid component includes 1,2,4-benzenetricarboxylic acid (trimellitic acid) and 1,2,4,5-benzenetetracarboxylic acid (pyromellitic acid), and anhydrides of these acids. Or alkyl (C1-C12) ester etc. are mentioned.

  The amorphous polyester resin can be produced in the same manner as the crystalline polyester resin described above. Further, the compounds exemplified in JP-A-7-175260 can be used in the same manner as described in the publication. When polymerizing the aforementioned monomers, an esterification catalyst such as dibutyltin oxide may be used as appropriate in order to promote the reaction.

  The weight average molecular weight (Mw) of the amorphous polyester resin is preferably 5000 or more and 200,000 or less, more preferably 7000 or more and 120,000 or less. If the weight average molecular weight of the amorphous polyester resin is less than 5000, the resin becomes too brittle, and when pulverized into toner particles, a large amount of fine powder having a particle diameter of 2 μm or less is generated, resulting in a lower classification yield. To do. On the other hand, if the weight average molecular weight of the amorphous polyester resin exceeds 200,000, the resin becomes too tough, the pulverization property of the toner is lowered, and the productivity is lowered.

  Further, the number average molecular weight (Mn) of the amorphous polyester resin is preferably 3,000 or more and 15,000 or less, more preferably 4,000 or more and 12,500 or less. The ratio (Mw / Mn) of the weight average molecular weight (Mw) to the number average molecular weight (Mn) is preferably 2.5 or more and 35.5 or less, more preferably 3.0 or more and 32.0 or less. is there.

The melt viscosity of the amorphous polyester resin is preferably 1 × 10 ³ Pa · s or more and 1 × 10 ⁵ Pa · s or less, more preferably 5 at a temperature of 100 ° C. from the viewpoint of offset resistance. It is not less than × 10 ³ Pa · s and not more than 5 × 10 ⁴ Pa · s.

  The acid value of the amorphous polyester resin is preferably 1 mgKOH / g or more and 20 mgKOH / g or less, more preferably 3 mgKOH / g or more and 15 mgKOH / g or less, from the viewpoint of the stability of chargeability of the toner. . The hydroxyl value of the amorphous polyester resin is preferably from 0.5 mgKOH / g to 5 mgKOH / g, more preferably from 0.5 mgKOH / g to 4 mgKOH / g, from the viewpoint of environmental stability of the toner. is there.

  A hybrid resin may be used as the amorphous resin. As described in JP-A-8-171231, a hybrid resin is prepared by mixing two polymerization-system raw monomers each having an independent reaction path, and carrying out the two polymerization reactions in the same reaction vessel. It is obtained by doing.

  The two polymerization reactions proceed through independent reaction paths, and are preferably a reaction that produces a condensation polymerization resin and a reaction that produces an addition polymerization resin. Typical examples of the condensation polymerization resins include polyester resins, polyester-polyamide resins, polyamide resins, and the like. Typical examples of addition polymerization resins include vinyl polymerization resins obtained by radical polymerization reaction.

  The polyester component in the polyester-polyamide resin includes a divalent or higher alcohol component exemplified as the raw material for the amorphous polyester resin and a carboxylic acid component such as a divalent or higher carboxylic acid, a carboxylic acid anhydride, and a carboxylic acid ester. Can be obtained as a raw material monomer.

  Examples of the raw material monomer used for forming the amide component in the polyester-polyamide resin or polyamide resin include various polyamines, aminocarboxylic acids, amino alcohols, and the like. Among these, hexamethylenediamine or ε -Caprolactam is preferably used.

  Raw material monomers used to form a vinyl polymerization resin obtained by addition polymerization reaction include ethylenically unsaturated monoolefins such as styrene, ethylene and propylene, diolefins such as butadiene, methacrylic acid and acrylics. Examples include ethylenic monocarboxylic acids such as acids, and esters of ethylenic monocarboxylic acids such as alkyl (carbon number 1 to 18) esters of methacrylic acid or acrylic acid.

  The hybrid resin is preferably produced as follows. First, the raw material monomer of the condensation polymerization resin, the raw material monomer of the addition polymerization resin, the polymerization initiator, etc. are mixed, and the condensation polymerization reaction is possible mainly by radical polymerization reaction at a temperature of 50 to 180 ° C. An addition polymerization resin component having a functional group is obtained. Next, the reaction temperature is increased to 190 to 270 ° C., and a condensation polymerization resin component is formed mainly by a condensation polymerization reaction. Thus, by proceeding two independent reactions in one reaction vessel, the compatibility of the two types of resins is improved, and a resin composition in which the two types of resins are uniformly mixed is efficiently obtained. be able to.

The weight ratio of the condensation polymerization resin to the addition polymerization resin, that is, the ratio of the weight W ₁ of the raw material monomer of the condensation polymerization resin to the weight W ₂ of the raw material monomer of the addition polymerization resin (W ₁ / W ₂ ) is preferably from 50/50 to 95/5, more preferably from 60/40 to 95/5, from the viewpoint of the dispersibility of the addition polymerization resin.

Physical property values such as the softening point, melting point and chloroform insoluble fraction of the crystalline resin such as the crystalline resin C, and the softening point, glass transition point and chloroform insoluble fraction of the amorphous resin such as the resin A and the resin B Can be easily adjusted by appropriately selecting the types and amounts of raw material monomers, polymerization initiators and catalysts used in the production of the resin, and reaction conditions.
In addition, the physical property value of the resin in this specification is a value measured as follows.

<Softening point Tm>
Using a Koka flow tester (manufactured by Shimadzu Corporation: CFT-500), a sample was heated at a heating rate of 6 ° C./min while applying a load of 20 kg / cm ² to 1 g of the sample. Let the temperature which flows out be softening point Tm. A nozzle having a diameter of 1 mm and a length of 1 mm was used.

<Melting point and glass transition point Tg>
Using a differential scanning calorimeter (Seiko Denshi Kogyo Co., Ltd .: DSC210), the DSC curve is measured by heating the sample at a heating rate of 10 ° C. per minute according to Japanese Industrial Standard (JIS) K7121-1987. The endothermic peak corresponding to the melting of the DSC curve, that is, the temperature at the top of the melting peak is defined as the melting point. In addition, the endothermic peak corresponding to the glass transition of the DSC curve was drawn at a point where the gradient is maximum with respect to the straight line extending from the high temperature side base line to the low temperature side and the curve from the peak rising portion to the apex. The temperature at the intersection with the tangent is defined as the glass transition point Tg.

<Chloroform insoluble fraction>
In a glass bottle with a capacity of 100 mL, put 5 g of a powder sample, 5 g of radiolite (manufactured by Showa Chemical Industry Co., Ltd .: # 700) and 100 mL of chloroform, and stir with a ball mill at a temperature of 25 ° C. for 5 hours. Chemical filter Co., Ltd .: # 700) Pressure filtration is performed with a filter paper (No. 2) manufactured by Toyo Filter Paper Co., Ltd. that is uniformly spread with 5 g. The solid on the filter paper is washed twice with 100 mL of chloroform, dried, and then weighed. From this value, the chloroform insoluble fraction is calculated according to the following formula.
Chloroform insoluble fraction (% by weight) = [weight of solid on filter paper (g) −10 g (weight of radiolite)] / 5 g (weight of sample) × 100

<Weight average molecular weight (Mw), number average molecular weight (Mn)>
Using SYSTEM-11 manufactured by Showa Denko KK, at a temperature of 40 ° C., a 0.25 wt% tetrahydrofuran solution is used as a sample solution, and measurement is performed with an injection amount of 100 mL. Two TSK gel GMH XLs manufactured by Tosoh Corporation are used for the column, and a refractive index detector is used for the detector. The molecular weight calibration curve is prepared using standard polystyrene.

<Acid value and hydroxyl value>
Measured according to JIS K0070.

<Melt viscosity>
It is measured using a melt viscosity measuring device (Paar Physica: PHYSICA USD200).

  As the negative charge control agent, a monomer containing 1 to 20% by weight of a sulfonic acid monomer and 99 to 80% by weight of a radical polymerizable monomer copolymerizable with the sulfonic acid monomer is used. Copolymer particles obtained by polymerization and having an average primary particle size of 0.01 μm to 2 μm, preferably 0.05 μm to 1 μm, are used. Here, the sulfonic acid monomer is a monomer having a sulfonic acid group, and the sulfonic acid group may be bonded to an appropriate cation such as an alkali metal ion to form a salt. Good.

  Since the copolymer particles include a sulfonic acid monomer in the monomer, the copolymer particles have a sulfonic acid group on the surface and have an appropriate polarity. The copolymer particles have an average primary particle size as small as 0.01 μm or more and 2 μm or less. For this reason, the copolymer particles are adequately compatible with the binder resin having a relatively low polarity and are uniformly dispersed in the toner particles, so that the characteristics can be sufficiently exhibited.

  That is, by incorporating the copolymer particles as a negative charge control agent in the toner of the present embodiment containing the above-described amorphous resin and crystalline resin as a binder resin, the characteristics of the copolymer particles can be obtained. Can be sufficiently exhibited, and the charging stability with time is good, and a toner having good charge rising characteristics especially at high temperature and high humidity can be obtained. Therefore, the toner can be easily charged to a desired charge amount at the time of frictional charging with a specific carrier to be described later, so that toner scattering and fogging can be suppressed, and a high-quality image can be realized.

  In the copolymer particles used as the negative charge control agent, if the ratio of the sulfonic acid monomer to the total amount of the monomer is less than 1% by weight, a sufficient charge amount is accumulated in the obtained toner. It becomes difficult. On the other hand, when the ratio of the sulfonic acid monomer to the total amount of the monomer exceeds 20% by weight, the electric resistance value of the obtained toner is lowered, the stability of the charge amount is deteriorated, and the binder resin and The compatibility of the toner deteriorates and the transparency of the toner is impaired. Therefore, the ratio of the sulfonic acid monomer to the total amount of monomers is set to 1% by weight or more and 20% by weight or less.

  Further, when the average particle size of the primary particles of the copolymer particles is less than 0.01 μm, the charge control ability per one of the copolymer particles is lowered, and the toner is charged to a desired charge amount. The toner is scattered, and the image quality is deteriorated. On the other hand, when the average particle size of the primary particles of the copolymer particles exceeds 2 μm, the copolymer particles contained per toner particle are used as compared with the case where the average particle size of the primary particles is 2 μm or less. Since the number of polymer particles decreases and it becomes difficult to charge the toner uniformly, toner scattering occurs and the image quality deteriorates. Therefore, the average particle diameter of the primary particles of the copolymer particles is set to 0.01 μm or more and 2 μm or less.

  The radically polymerizable monomer that is a raw material of the copolymer particles is not particularly limited as long as it is copolymerizable with the sulfonic acid monomer that is a copolymerization component. Although it can be appropriately selected and used, it is preferable to use one that is easily copolymerized with the sulfonic acid monomer.

  Specific examples of the radical polymerizable monomer include vinyl monomers, for example, styrene monomers such as styrene and α-methylstyrene, acrylic monomers such as methacrylic acid alkyl esters and acrylic acid alkyl esters, Examples include vinyl acetate, vinyl propionate, vinyl chloride, and acrylonitrile. One of these monomers may be used alone, or two or more thereof may be used in combination.

  As the sulfonic acid monomer, a vinyl monomer having a sulfonic acid group can be used. Specific examples include 2-acrylamido-2-methylpropanesulfonic acid, styrene sulfonic acid soda, sulfoethylacrylic. Examples thereof include sulfoalkylacrylic acid-based or sulfoalkylmethacrylic acid-based monomers such as acid, sulfoethylmethacrylic acid, and sulfoethylmethacrylate sodium. One of these monomers may be used alone, or two or more thereof may be used in combination.

  Among the above-mentioned monomers, styrene monomers and / or radical polymerizable monomers are preferred because they are easy to polymerize and copolymer particles having a softness that is preferable as a component of toner can be easily obtained. It is preferable to use an acrylic monomer and 2-acrylamido-2-methylpropanesulfonic acid as the sulfonic acid monomer.

  The copolymer particles are preferably produced by copolymerizing the above-mentioned radical polymerizable monomer and sulfonic acid monomer by an emulsion polymerization method. By producing the copolymer particles by emulsion polymerization of a radical polymerizable monomer and a sulfonic acid monomer, the primary particles have an average particle diameter of 0.01 μm to 2 μm, preferably 0.05 μm or more. Fine copolymer particles having a size of 1 μm or less can be easily obtained. Moreover, the molecular weight of the polymer obtained by the emulsion polymerization method is relatively larger than the molecular weight of the polymer obtained by the solution polymerization method or the suspension polymerization method. Also, since the sulfonic acid group of the sulfonic acid monomer used as the copolymer component is hydrophilic, the surface of the copolymer particles produced by the emulsion polymerization method has a high sulfonic acid group concentration.

  As described above, the copolymer particles obtained by the emulsion polymerization method have a small primary particle diameter, a large molecular weight, and a high sulfonic acid group concentration on the surface. When melt kneaded together with a resin and a colorant, it is less likely to be melted by heat compared to a copolymer-based negative charge control agent produced by a solution polymerization method or a suspension polymerization method, etc. Inferred. For this reason, the copolymer particles obtained by the emulsion polymerization method are uniformly dispersed in the binder resin while maintaining the state of the primary particles having a high concentration of sulfonic acid groups on the surface at the end of the hot melt kneading step. It is thought that.

  That is, in the toner using the copolymer particles obtained by the emulsion polymerization method as the negative charge control agent, the negative charge control agent fine particles having a high sulfonic acid group concentration on the surface are mixed with the binder resin in a particle state. On the other hand, in a toner using a copolymer charge control agent obtained by a solution polymerization method or a suspension polymerization method, it is considered that the negative charge control agent is mixed in the binder resin in a substantially complete compatible state. . When the negative charge control agent is mixed in the binder resin in an almost complete compatibility state, the characteristics as the negative charge control agent are not sufficiently exhibited, and the chargeability of the toner cannot be sufficiently controlled. Therefore, in order to fully exhibit the characteristics of the copolymer particles as a negative charge control agent, it is preferable to use the copolymer particles obtained by an emulsion polymerization method. By using the copolymer particles obtained by an emulsion polymerization method, the copolymer particles are uniformly dispersed in a particle state in a binder resin, and the characteristics of the copolymer particles are sufficiently exhibited. The stability over time of charging, particularly the rising characteristics of charging at high temperature and high humidity, is further improved.

  The emulsion polymerization method for producing the copolymer particles is not particularly limited, and a known method can be used. However, in consideration of the solubility of the sulfonic acid monomer in water, when adding the monomer to the solvent water so that the copolymerizability with the radical polymerizable monomer is improved, It is preferable to polymerize by dropping the body or adding monomers little by little. In particular, it is preferable that the radically polymerizable monomer and the sulfonic acid monomer are separately dropped into a polymerization vessel and emulsion polymerized. For example, by radically dropping an aqueous solution of a radical polymerizable monomer and an aqueous solution of a sulfonic acid monomer into a polymerization vessel containing water and an emulsifier such as sodium dodecyl sulfate, a radical polymerizable monomer And the sulfonic acid monomer can be copolymerized quickly.

  The copolymer after emulsion polymerization is taken out from the polymerization system as the copolymer particles by a vacuum drying method, a spray drying method or a salting out method. The copolymer particles may be agglomerated when taken out from the polymerization system. Since the copolymer particles obtained by emulsion polymerization have a high sulfonic acid group concentration on the surface as described above, even in the case where aggregation occurs in the extracted copolymer particles, Easily dispersed to primary particles. Therefore, a good dispersion state of the copolymer particles in the toner particles is maintained.

  As the negative charge control agent, the copolymer particles obtained as described above may be used alone, or two or more copolymer particles produced from different monomers may be mixed. May be used.

  As the colorant, a known black colorant or chromatic colorant can be used. The color of the colorant is appropriately selected so that a toner having a desired color is realized. For example, a black colorant is used when manufacturing a black toner, and a chromatic colorant corresponding to each color is used when manufacturing a color toner.

  As the black colorant, various carbon blacks classified according to the production method are preferably used. Specific examples thereof include furnace black, channel black, acetylene black, thermal black and lamp black.

  As the chromatic colorant, an organic pigment is preferably used, and specific examples thereof include the following pigments classified by color index (abbreviation: CI) numbers. Examples of blue organic pigments include phthalocyanine pigment blue 15: 3 and indanthrone pigment blue 60. Examples of red organic pigments include quinacridone pigment red 122, azo pigment red 22, 48: 1, 48: 3, and 57: 1. Examples of yellow organic pigments include azo pigment yellows 12, 13, 14, and 17, isoindolinone pigment yellow 110, and benzimidazolone pigment yellows 151, 154, and 180.

  The amount of the colorant used is preferably 1 part by weight or more and 20 parts by weight or less, more preferably 2 parts by weight or more and 10 parts by weight or less with respect to 100 parts by weight of the binder resin.

  The toner particles according to the present embodiment preferably contain a wax in addition to the binder resin, the colorant, and the negative charge control agent. By including wax in the toner particles, the low-temperature fixability, offset resistance, blocking resistance (storage stability) and fluidity of the toner can be improved.

  As the wax, natural wax such as montanic acid ester wax, polyolefin wax such as high pressure polyethylene or high pressure polypropylene, silicone wax, fluorine wax and the like can be used. These waxes are commercially available, and suitable waxes include SANYO Kasei Kogyo Co., Ltd. Viscol 660P, Biscol 550P, Biscol 330P, TP-32 (trade name), Mitsui Chemicals Mitsui. High wax NP505, P200, P300, P400 (brand name) etc. are mentioned.

  Among the waxes described above, the penetration specified in JIS K2207 is 1.5 or less, preferably 1.0 or less, and the melting point is 80 ° C. or higher and 110 ° C. or lower, preferably 85 ° C. or higher and 105 ° C. or lower. It is preferable to use a wax. By using such a wax in combination with the aforementioned crystalline resin, it is possible to easily achieve both low temperature fixability and storage stability and optimization. The smaller the penetration of the wax, the better.

  In this specification, the melting point of a wax is an endothermic peak corresponding to melting of a DSC curve measured by a differential scanning calorimeter (DSC), that is, the temperature at the top of the melting peak. Using SSC-5200 manufactured by the company, the sample was heated from a temperature of 20 ° C. to 150 ° C. at a rate of temperature increase of 10 ° C. per minute, and then rapidly cooled from 150 ° C. to 20 ° C. twice. It is obtained from the measured DSC curve.

  The wax having a penetration and melting point within the above ranges is not particularly limited, but Fischer-Tropsch wax (hereinafter also referred to as FT wax) is preferably used, and purified FT wax is particularly preferably used. The degree of purification of the FT wax is indicated by the half width of the melting peak, and the degree of purification of the purified FT wax is usually 15 ° C. or less, preferably 10 ° C. or less, in terms of the half width of the melting peak.

  Fischer-Tropsch wax is a wax-like hydrocarbon synthesized by catalytic hydrogenation of carbon monoxide using the Fischer-Tropsch process, and is a linear paraffinic wax with few methyl branches structurally. In the present embodiment, it is preferable to use natural gas Fischer-Tropsch wax produced by the Fischer-Tropsch method using natural gas as a raw material. Examples of such natural gas-based FT wax include FT-100, FT-0030, FT-0050, FT-0070, FT-0165, FT-1155, and FT-60S (trade names) manufactured by Shell MDS. It is commercially available.

  As described above, the FT wax preferably has a melting point of 80 ° C. or higher and 110 ° C. or lower. When FT wax having a melting point lower than 80 ° C. is used, it is difficult to obtain the effect of improving the storage stability and fluidity of the toner. In addition, since FT wax having a melting point higher than 110 ° C. has little effect of lowering the melt viscosity of the toner, even if such FT wax is used, the effect of improving the low-temperature fixability of the toner is hardly obtained.

  These waxes may be used alone or in a combination of two or more.

The ratio (W _C / W _W ) between the weight Wc of the crystalline resin and the weight W _{W of the} wax in the toner is preferably from 1/1 to 4/1, more preferably from 2/1 to 3 /. 1 or less. By selecting the ratio W _C / W _W within the above range, the dispersibility of the wax in the toner is improved, and the effect of improving the low-temperature fixability, offset resistance, blocking resistance and fluidity of the toner is sufficient. To be demonstrated. However, since the FT wax is not very compatible with the binder resin, the dispersibility in the binder resin deteriorates when used in a large amount. If the dispersibility of the wax is deteriorated, the wax tends to be detached in the pulverization process at the time of producing the toner, and it is difficult to obtain the effect of improving the offset resistance and fluidity of the toner. Therefore, the amount of FT wax used is preferably 1 to 10 parts by weight, more preferably 2 to 6 parts by weight, with respect to 100 parts by weight of the binder resin.

  In order to improve the powder fluidity, it is preferable to add an external additive to the toner particles according to the present embodiment containing the materials described above. The external additive may be added so as to adhere to the surface of the toner particles, or may be added so that a part thereof is embedded in the toner particles.

  Examples of the external additive include inorganic fine particles such as silica, and among these, those having hydrophobic properties are particularly preferably used. Examples of the hydrophobized silica fine particles include those obtained by surface-treating silicon dioxide with various polyorganosiloxanes or silane coupling agents. Such hydrophobized silica fine particles include, for example, AEROSIL R972, R974, R202, R805, R812, RX200, RY200, R809, RX50 (trade name) manufactured by Nippon Aerosil Co., Ltd., manufactured by Wacker Chemicals East Asia Co., Ltd. WACKER HDK H2000, H2050EP (product name), Nippon Sil SS-10, SS-15, SS-20, SS-50, SS-60, SS-100, SS-50B, SS-50F manufactured by Nippon Silica Kogyo Co., Ltd. , SS-10F, SS-40, SS-70, SS-72F (trade name) and the like.

  The silica fine particles used for the external additive include those having a relatively large average particle diameter and those having a relatively small average particle diameter, and these may be used alone or in combination.

  The amount of external additives such as silica fine particles is determined in consideration of the charge amount to be applied to the toner, the influence on the photoreceptor, the environmental characteristics of the toner, and the like. On the other hand, it is preferably 0.1 to 5 parts by weight, more preferably 0.2 to 3 parts by weight.

  Next, a toner manufacturing method according to the present embodiment will be described. The toner according to the present embodiment can be manufactured by a known method such as a kneading and pulverizing method, a spray drying method, or a polymerization method. For example, the toner is manufactured as follows.

  First, various additives such as wax are added to the binder resin including the above-described amorphous resin and crystalline resin, the colorant, and the copolymer particles as necessary, and the mixture is uniformly mixed with a mixer such as a ball mill. Mix. Each resin contained in the binder resin may be used in the form of a powder or pellet of each resin, or after being uniformly mixed and dispersed by melt-kneading and then pulverized or the like. Alternatively, it may be used in the form of pellets. In addition, the colorant may be used after being subjected to a flushing treatment in advance so as to be uniformly dispersed in the binder resin, or may be previously melt-kneaded with a part of the binder resin and colored in the binder resin. The agent may be used as a master batch in which the agent is dispersed at a high concentration.

  Next, the obtained mixture is melt-kneaded by a kneading means such as a two-roll kneader, a three-roll kneader, a pressure kneader, a closed kneader, or a single or twin screw extruder. The obtained kneaded product is cooled, and then finely pulverized by a pulverizer such as a jet mill, and classified by an air classifier as necessary to obtain toner particles.

  When the above-mentioned external additives are added to the toner particles, for example, an ordinary powder mixer such as a Henschel mixer or a so-called surface reformer such as a hybridizer is used to add the externally added toner particles to the toner particles after pulverization or classification. Mix the agent uniformly.

  The volume average particle diameter of the toner particles thus obtained or toner particles to which an external additive is added is preferably 5 μm or more and 10 μm or less, more preferably 5 μm or more and 8 μm or less.

The developer of the present embodiment has a specific carrier, that is, an electrical resistivity R (Ω · cm) of 12 to 25 in terms of a common logarithmic value (Log R) with respect to the toner manufactured as described above. Yes,
The first fluidity index F1 represented by the following formula (1) is 63 sec / (50 · cm ³ ) or more and 75 sec / (50 · cm ³ ) or less,
A carrier having a second fluidity index F2 expressed by the following formula (2) of 30 Oe · g / cm ³ or more and 100 Oe · g / cm ³ or less is combined.
F1 = AD × FR (1)
F2 = AD × Hc (2)
Where AD: apparent density (g / cm ³ ),
FR: fluidity (sec / 50 g),
Hc: Coercive force (Oe) when a magnetic field of 3000 Oe is applied

  As a result, it is possible to obtain a developer that is excellent in low-temperature fixing property, offset resistance, and blocking resistance of the toner, and that is free from carrier adhesion and toner scattering and can realize a high-quality image without fogging.

  Hereinafter, the electrical resistivity R will be described. As described above, the carrier used in the developer of the present embodiment has an electrical resistivity R (Ω · cm) of 12 or more and 25 or less, more preferably 13 or more, 20 in terms of a common logarithmic value (LogR). Or less, more preferably 13 or more and 18 or less. By using a carrier having a LogR in the above range, it is possible to suppress the occurrence of carrier adhesion and realize an image having a sufficient image density.

  In general, a carrier for a color developer used for forming a color image has a low resistance of LogR smaller than 12 in order to obtain a sufficient toner adhesion amount, and a carrier having a LogR in the above range is used. When used in a color developer, a sufficient toner adhesion amount cannot be obtained, and the image density may be lowered. However, the developer of the present embodiment is a combination of a carrier having an electric resistance R in the above range and a toner containing the above-described amorphous resin, crystalline resin and copolymer particles. An appropriate charge amount can be imparted to the toner, whereby a sufficient toner adhesion amount can be obtained, and a sufficient image density can be obtained.

  When Log R is less than 12 and the electrical resistivity R is low, when the developing gap, which is the closest distance between the photosensitive member and the developing sleeve, is narrow, charges are induced in the carrier and carrier adhesion is likely to occur. . The occurrence of carrier adhesion due to the induction of charges on the carrier tends to be worsened when the linear velocity of the photosensitive member is high and when the linear velocity of the developing sleeve is high. In particular, an alternating current (AC) bias voltage is applied to the photosensitive member. This is remarkable when applied. On the other hand, if LogR exceeds 25, a proper charge amount cannot be imparted to the toner, the toner adhesion amount is insufficient, and a sufficient image density cannot be obtained. Therefore, LogR is set to 12 or more and 25 or less.

  The electrical resistivity R of the carrier can be measured by the following method. FIG. 1 is a perspective view schematically showing the configuration of a resistance measuring cell 11 used for measuring the electrical resistivity R of a carrier. In the present embodiment, as shown in FIG. 1, as the resistance measuring cell 11, two electrodes 12a and 12b having an interelectrode distance L of 2 mm, a surface facing each other of 2 cm in length, and 4 cm in width are disposed inside. Using the fluororesin container provided, the carrier 13 is filled between the electrode 12a and the electrode 12b, and in this state, a DC voltage of 100 V is applied between both electrodes, and a high resistance meter 4329A (manufactured by Yokogawa Hewlett-Packard Co., Ltd .: 4329A + LJK 5HVLVWDQFH OHWHU) to measure the DC resistance and calculate the electrical resistivity R (Ω · cm).

Next, the first fluidity index F1 (hereinafter simply referred to as F1) will be described. F1 indicates the fluidity per unit volume of the carrier in the agitation part which is not affected by the magnetic field in the developing device in which the developer is accommodated. In the carrier according to the present embodiment, as described above, F1 is 63 sec / (50 · cm ³ ) or more and 75 sec / (50 · cm ³ ) or less, preferably 65 sec / (50 · cm ³ ) or more and 72 sec. / (50 · cm ³ ) or less. By using the carrier in which F1 is in the above range, it is possible to suppress the deviation of the developer in the developing device and make the image density of the formed image uniform. Further, since the developer can be sufficiently agitated with a load that does not cause deterioration, it is possible to suppress the occurrence of toner scattering and fogging and to maintain good developer characteristics over a long period of time.

If F1 is less than 63 sec / (50 · cm ³ ), the fluidity is too good, and the developer is biased. Therefore, the development on the developing sleeve becomes uneven and the development in contact with the photosensitive member is caused. There arises a problem that the image density differs depending on the position of the sleeve. Further, in a portion where the developer is biased, the load during stirring is large, so that there is a problem that the developer characteristics deteriorate early. On the other hand, if F1 exceeds 75 sec / (50 · cm ³ ), the fluidity is too bad, and the transportability and stirrability are deteriorated. Therefore, the developer is biased, and F1 is 63 sec / (50 · cm ³ ). The same problem as in the case of less than the above occurs. Further, since the toner and the carrier are not sufficiently stirred, toner scattering and fogging occur. In order to suppress the occurrence of toner scattering and fogging, it is considered that the load on the developer during stirring is increased and the toner and the carrier are sufficiently stirred. However, the developer load is increased due to the increased load on the developer. Degradation is encouraged. Therefore, F1 was set to 63 sec / (50 · cm ³ ) or more and 75 sec / (50 · cm ³ ) or less.

Next, the second fluidity index F2 (hereinafter simply referred to as F2) will be described. F2 indicates the fluidity per unit volume of the carrier on the developing sleeve that is affected by the magnetic field in the developing device. F2 also indicates the rise of the magnetic brush on the developing sleeve and the length of the carrier chain (the degree of the carrier chain formed across the magnetic poles of the developing sleeve). In the carrier according to the present embodiment, F2 is 30 Oe · g / cm ³ or more and 100 Oe · g / cm ³ or less as described above, preferably 50 Oe · g / cm ³ or more, 90 Oe · g / cm ³ or less. It is. By using the carrier having F2 in the above range, the ears of the magnetic brush are formed on the developing sleeve with moderate softness and moderately densely and uniformly, so that a high quality image can be obtained. . Moreover, generation | occurrence | production of carrier adhesion can be suppressed.

If F2 is less than ³⁰ Oe · g / cm ³ , the ears of the magnetic brush formed on the developing sleeve become sparse, and it becomes difficult to supply toner to the electrostatic latent image, so that sufficient developability is obtained. In addition, toner scattering may occur because the toner cannot be sufficiently retained. Also, since the carrier chain is short and standing, the ears of the magnetic brush become stiff and high-quality images cannot be obtained, and the magnetic field at the tip of the carrier chain is weakened. Become. On the other hand, if F2 exceeds 100 Oe · g / cm ³ , the ears of the magnetic brush become dense, but the fluidity deteriorates and the movement of the developer on the developing sleeve becomes worse. It becomes uniform, and toner is not sufficiently supplied to the electrostatic latent image, so that the image quality is deteriorated. Also, the adhesion of the carrier increases because the ears of the magnetic brush become too dense and the pressing force against the photoreceptor increases. Therefore, F2 is set to 30 Oe · g / cm ³ or more and 100 Oe · g / cm ³ or less.

  The carrier preferably has a coercive force Hc (hereinafter simply referred to as Hc) of 12 Oe or more and 60 Oe or less, more preferably 30 Oe or more and 55 Oe or less when a magnetic field of 3000 oersted (Oe) is applied. is there. If Hc is less than 12 Oe, the carrier chain is less likely to become dense on the developing sleeve, and developability is deteriorated. When Hc exceeds 60 Oe, the fluidity of the developer on the developing sleeve is deteriorated, and it becomes difficult to supply the toner to the electrostatic latent image, and the developability is deteriorated. Further, even after the carrier is separated from the developing sleeve, the carriers are not sufficiently loosened and are not easily mixed with the newly supplied toner in the agitating portion, and the developability is lowered. Therefore, Hc is preferably 12 Oe or more and 60 Oe or less.

  The carrier preferably has a saturation magnetization of 20 emu / g or more and 45 emu / g or less, more preferably 22 emu / g or more and 38 emu / g or less when a magnetic field of 3000 Oe is applied. When the saturation magnetization when a magnetic field of 3000 Oe is applied is less than 20 emu / g, the carrier tends to adhere to the photoconductor, and when it exceeds 45 emu / g, the ear tends to become hard and a high quality image is obtained. It becomes difficult. Therefore, the saturation magnetization when a carrier magnetic field of 3000 Oe is applied is preferably 20 emu / g or more and 45 emu / g or less.

  Further, the carrier preferably has a weight average particle diameter Dw of 30 μm or more and 120 μm or less, more preferably 35 μm or more and 80 μm or less, and further preferably 35 μm or more and 60 μm or less. If the weight average particle diameter Dw of the carrier is less than 30 μm, it is effective for obtaining a high-quality image, but the magnetization per carrier particle is lowered, which causes carrier adhesion. If the weight average particle diameter Dw of the carrier exceeds 120 μm, the specific surface area becomes small and the charging ability becomes low. Therefore, it becomes difficult to give a sufficient charge amount to the toner, which causes image quality deterioration. Therefore, the weight average particle diameter Dw of the carrier is preferably 30 μm or more and 120 μm or less.

  In this specification, the apparent density AD, the fluidity FR, the magnetic properties such as the coercive force Hc and the saturation magnetization, and the weight average particle diameter Dw of the carrier are values measured as follows.

<Apparent density AD>
Measured in accordance with “Apparent Density Test Method for Metallic Powder” defined in JIS Z2504.

<Fluidity FR>
Measured in accordance with “Metal powder flow rate test method” defined in JIS Z2502.

<Magnetic properties>
The coercive force Hc and saturation magnetization are read from a hysteresis curve obtained by applying a magnetic field of 3000 oersted (Oe) using a BH tracer (manufactured by Riken Denshi Co., Ltd .: BHU-60 type).

<Weight average particle diameter Dw>
It is measured using a Microtrac particle size distribution meter (manufactured by Nikkiso Co., Ltd .: Model 9320-X100).

  As the carrier, magnetic particles themselves may be used, or a carrier comprising a carrier core material that is magnetic particles and a coating layer that covers the surface of the carrier core material may be used. . Among these, the carrier constituted by including the carrier core material and the coating layer is preferable because the electric resistivity R, the first fluidity index F1, and the second fluidity index F2 can be easily adjusted. Used.

  Examples of the magnetic material constituting the carrier or the carrier core material include iron powder, ferrite, and magnetite. Among these, ferrite is preferably used. By using ferrite for the carrier core material, a carrier having the electrical resistivity R, the first fluidity index F1, and the second fluidity index F2 in the above ranges can be easily realized.

  As the coating layer, a resin layer made of a resin is preferably used. As the resin constituting the coating layer, various conventionally known resins used for the production of carriers can be used. Specifically, polystyrene, chloropolystyrene, poly-α-methylstyrene, styrene-chlorostyrene copolymer Polymer, styrene-propylene copolymer, styrene-butadiene copolymer, styrene-vinyl chloride copolymer, styrene-vinyl acetate copolymer, styrene-maleic acid copolymer, styrene-acrylic acid ester copolymer (styrene -Methyl acrylate copolymer, styrene-ethyl acrylate copolymer, styrene-butyl acrylate copolymer, styrene-octyl acrylate copolymer, styrene-phenyl acrylate copolymer, etc.), styrene-methacrylic acid Ester copolymer (styrene-methyl methacrylate copolymer, styrene Ethyl methacrylate copolymer, styrene-butyl methacrylate copolymer, styrene-phenyl methacrylate copolymer, etc.), styrene-α-methyl acrylate copolymer, styrene-acrylonitrile-acrylate copolymer, etc. Styrene resin, silicone resin, epoxy resin, polyester resin, polyethylene resin, polypropylene resin, ionomer resin, polyurethane resin, ketone resin, ethylene-ethyl acrylate copolymer, xylene resin, polyamide resin, phenol resin, polycarbonate resin, melamine Examples thereof include resins and fluorine resins.

  Among these resins, in the present embodiment, a silicone resin containing at least one of a repeating unit represented by the following general formula (II) and a repeating unit represented by the following general formula (III) is preferably used. .

In the general formula (II), R ² represents a hydrogen atom, a halogen atom, a hydroxyl group, a methoxy group, a lower alkyl group having 1 to 4 carbon atoms, or an aryl group. R ³ represents an alkylene group having 1 to 4 carbon atoms or an arylene group. Specific examples of the aryl group represented by R ² include a phenyl group and a tolyl group. Specific examples of the arylene group represented by R ³ include a phenylene group.

In the general formula (III), R ⁴ and R ⁵ each represent a hydrogen atom, a halogen atom, a hydroxyl group, a methoxy group, a lower alkyl group having 1 to 4 carbon atoms, or an aryl group. Specific examples of the aryl group represented by R ⁴ or R ⁵ include a phenyl group and a tolyl group.

  Examples of the silicone resin include straight silicone resins. The straight silicone resin is available as a commercial product, and preferable examples include KR271, KR272, KR282, KR252, KR255, KR152 (trade name) manufactured by Shin-Etsu Chemical Co., Ltd., Toray Dow Corning Silicone Co., Ltd. SR2400, SR2406 (trade name), etc., manufactured

  Examples of the silicone resin include modified silicone resins such as epoxy-modified silicone, acrylic-modified silicone, phenol-modified silicone, urethane-modified silicone, polyester-modified silicone, and alkyd-modified silicone. The modified silicone resin is available as a commercial product, and preferred examples include ES-1001N (epoxy-modified product), KR-5208 (acryl-modified silicone), KR-5203 (polyester-modified product) manufactured by Shin-Etsu Chemical Co., Ltd. Product), KR-206 (alkyd modified product), KR-305 (urethane modified product), SR2115 (epoxy modified product) manufactured by Toray Dow Corning Silicone Co., Ltd., SR2110 (alkyd modified product), and the like.

The silicone resin may contain an appropriate amount of an aminosilane coupling agent, for example, 0.001 wt% to 30 wt%. Examples of the aminosilane coupling agent that can be used include the following compounds (a) to (i).
_{(A) H 2 N (CH} 2) 3 Si (OCH 3) 3 [ molecular weight: 179.3]
(B) H ₂ N (CH ₂ ) ₃ Si (OC ₂ H ₅ ) ₃ [Molecular weight: 221.4]
(C) H ₂ N (CH ₂ ) ₃ Si (CH ₃ ) ₂ (OC ₂ H ₅ ) [Molecular weight: 161.3]
_{(D) H 2 N (CH} 2) 3 Si (CH 3) (OC 2 H 5) 2 [ molecular weight: 191.3]
_{(E) H 2 N (CH} 2) 2 NHCH 2 Si (OCH 3) 3 [ molecular weight: 194.3]
_{(F) H 2 N (CH} 2) 2 NH (CH 2) 3 Si (CH 3) (OCH 3) 2
[Molecular weight: 206.4]
(G) H ₂ N (CH ₂ ) ₂ NH (CH ₂ ) ₃ Si (OCH ₃ ) ₃ [Molecular weight: 224.4]
(H) (H ₃ C) ₂ N (CH ₂ ) ₃ Si (CH ₃ ) (OC ₂ H ₅ ) ₂ [Molecular weight: 219.4]
_{(I) (H 9 C 4} ) 2 N (CH 2) 3 Si (OCH 3) 3 [ molecular weight: 291.6]

  As for the resin such as the silicone resin exemplified as the resin constituting the coating layer, one kind may be used alone, or two or more kinds may be mixed and used.

  The resin layer provided on the surface of the carrier core particle can be formed by a known method such as a spray drying method, a dipping method, or a powder coating method. In particular, a method using a fluidized bed type coating apparatus is preferably used because a uniform coated film can be formed.

  The carrier core material may be baked after being coated with the resin. Baking may be performed by either an external heating method or an internal heating method. The external heating type baking is performed by a fixed or fluid electric furnace, a rotary electric furnace, or a burner furnace. The internal heating method is performed by microwaves or the like. Although the baking temperature varies depending on the resin used, it must be higher than the melting point or glass transition point of the resin. When using a thermosetting resin or a condensation-crosslinking resin, the baking temperature is higher than the temperature at which the curing proceeds sufficiently. It is necessary to be.

  In this way, the surface of the carrier core material is coated with the resin, and after baking as necessary, the carrier core material is cooled and crushed, and the particle size is adjusted, thereby adjusting the particle size from the carrier core material coated with the resin layer. A carrier is obtained.

  The weight of the coating layer such as a resin layer formed on the surface of the carrier core material particles is preferably 0.8 parts by weight or more and 15 parts by weight or less, more preferably 100 parts by weight of the carrier core material. 3 parts by weight or more and 12 parts by weight or less, more preferably 4 parts by weight or more and 12 parts by weight or less. When the weight of the coating layer relative to 100 parts by weight of the carrier core material is less than 0.8 parts by weight, the coating layer is easily peeled off, and it is difficult to maintain good development characteristics. This is not preferable because the cost increases. Therefore, the weight of the coating layer with respect to 100 parts by weight of the carrier core material is preferably 0.8 parts by weight or more and 15 parts by weight or less.

  Moreover, it is preferable that the thickness of a coating layer is 0.02 micrometer or more and 1 micrometer or less, More preferably, it is 0.03 micrometer or more and 0.8 micrometer or less. Thus, since the thickness of the coating layer is extremely small, the particle size distribution of the carrier composed of the carrier core material particles coated with the coating layer is substantially the same as the particle size distribution of the carrier core material particles. Therefore, a carrier having a weight average particle diameter Dw of 30 μm or more and 120 μm or less can be obtained by using particles having a weight average particle diameter of about 30 to 120 μm as the carrier core material.

  Further, the magnetic properties of the carrier including the carrier core material and the coating layer are substantially the same as the magnetic properties of the carrier core material.

  The electrical resistivity R of the carrier can be easily controlled by adjusting the electrical resistivity and the film thickness of the coating layer in the carrier configured to include the carrier core material and the coating layer. Adjustment of the electrical resistivity of the coating layer may be performed by the material itself such as a resin constituting the coating layer, or may be performed by adding conductive fine powder to the coating layer.

As the conductive fine powder added to the coating layer, conductive zinc oxide (chemical formula: ZnO), metal such as aluminum (chemical formula: Al) or metal oxide powder, tin dioxide prepared by various methods (chemical formula: SnO ₂ ), semiconductor powder such as SnO ₂ doped with various elements, titanium diboride (chemical formula: TiB ₂ ), zinc diboride (chemical formula: ZnB ₂ ), molybdenum diboride (chemical formula: MoB ₂ ) Boron such as silicon carbide, polyacetylene, poly (p-phenylene), poly (p-phenylene sulfide), polypyrrole, conductive polymer such as polyethylene, carbon black such as furnace black, acetylene black, channel black, etc. It is done.

  In the case where the coating layer is composed of a resin layer, these conductive fine powders are, for example, dispersed in a coating resin solution formed by dispersing the resin together with a resin in an appropriate solvent, or dissolving the above resin in an appropriate solvent. Distributed and used. After the conductive fine powder is put into a solvent or coating resin solution, it is dispersed in the solvent or coating resin solution by using a dispersing machine using a medium such as a ball mill or a bead mill, or a stirrer equipped with a blade rotating at high speed. Can be uniformly dispersed.

  In the developer of the present embodiment, the toner and the carrier produced as described above have a toner concentration of preferably 1% by weight to 10% by weight, more preferably 2% by weight to 8% by weight. So that it is obtained by mixing.

[Production example]
(A) Production of crystalline resin (Crystalline polyester resin C-1)
In a four-necked flask, 415 parts by weight of terephthalic acid (2.5 mole parts), 415 parts by weight of isophthalic acid (2.5 mole parts), polyoxyethylene (2.0) -2,2-bis (4 -Hydroxyphenyl) propane (in the general formula (I), R ¹ is an ethylene group, and the average value of the sum of x and y (x + y) is 2.0) 1519 parts by weight (4.8 mol) Part), set a stirrer, condenser and thermometer, blow nitrogen gas, add 0.07% by weight of dibutyltin oxide as a catalyst to the total acid components, and dehydrate condensation at a temperature of 220 ° C. The reaction was carried out for 15 hours while removing the water produced by the above step to obtain a linear crystalline polyester resin C-1. The obtained crystalline polyester resin C-1 had Mw: 11000, Mn: 4100, softening point: 143 ° C., melting point: 121 ° C., acid value: 4.2, hydroxyl value: 1.2.

(Crystalline polyester resin C-2)
Instead of 1519 parts by weight (4.8 moles) of polyoxyethylene (2.0) -2,2-bis (4-hydroxyphenyl) propane, polyoxyethylene (2.0) -2,2-bis ( 823 parts by weight (2.6 mol parts) of 4-hydroxyphenyl) propane and polyoxypropylene (2.0) -2,2-bis (4-hydroxyphenyl) propane (in the general formula (I), R ¹ Is a propylene group, and the average value of the sum of x and y (x + y) is 2.0) except that 758 parts by weight (2.2 mol parts) is used. In the same manner as in the production, a crystalline polyester resin C-2 was produced. The obtained crystalline polyester resin C-2 had Mw: 12000, Mn: 4300, softening point: 137 ° C, melting point: 116 ° C, acid value: 4.7, and hydroxyl value: 1.9.

(Crystalline polyester resin C-3)
After 707 parts by weight (3.5 parts by mole) of sebacic acid, 496 parts by weight of 1,6-hexanediol (4.2 parts by mole) and 1.5 parts by weight of dibutyltin oxide were uniformly dissolved, dehydration was performed. The reaction was carried out at a temperature of 120 ° C. for 8 hours. Next, the temperature was gradually raised to 200 ° C., and the reaction was further carried out under reduced pressure. Thereafter, the temperature was lowered to 130 ° C., 80 parts by weight (0.78 mole part) of acetic anhydride was added and reacted for 3 hours, and then the produced acetic acid and excess acetic anhydride were distilled off to obtain a crystalline polyester resin. C-3 was obtained. The obtained crystalline polyester resin C-3 had Mw: 12,500, Mn: 4,200, softening point: 85 ° C., melting point: 65 ° C., acid value: 10, and hydroxyl value: 2.

(Crystalline polyester resin C-4)
1008 parts by weight (7.0 mol parts) of cyclohexanedimethanol and polyoxyethylene (2.2) -2,2-bis (4-hydroxyphenyl) propane (in the general formula (I), R ¹ is an ethylene group) The average value of the sum of x and y (x + y) is 2.2) 975 parts by weight (3.0 parts by mole), 1461 parts by weight (8.8 parts by weight) and dibutyl After adding 2.0 parts by weight of tin oxide and dissolving it uniformly, it was reacted at a temperature of 120 ° C. for 8 hours while dehydrating. Thereafter, the temperature was gradually raised to 200 ° C., and further reacted under reduced pressure to obtain a crystalline polyester resin C-4. Crystalline polyester resin C-4 obtained had Mw: 11,500, Mn: 3,200, softening point: 110 ° C., melting point: 92 ° C., acid value: 16, and hydroxyl value: 35.

(Crystalline polyester resin C-5)
The production of the crystalline polyester resin C-4 except that the amount of polyoxyethylene (2.2) -2,2-bis (4-hydroxyphenyl) propane used is 895 parts by weight (2.8 parts by mole) Similarly, crystalline polyester resin C-5 was obtained. Crystalline polyester resin C-5 obtained had Mw: 12,000, Mn: 3,650, softening point: 99 ° C., melting point: 85 ° C., acid value: 18, and hydroxyl value: 3.4.

(B) Production of amorphous resin The raw materials and catalyst shown in Table 1 were reacted at a temperature of 220 ° C in xylene under a nitrogen atmosphere. The degree of polymerization was monitored by acid value, and the reaction was terminated when the acid value reached 1.5 mgKOH / g or less. Amorphous polyester resin A- having a softening point Tm of 120 ° C. to 170 ° C. measured by using a Koka type flow tester (manufactured by Shimadzu Corporation: CFT-500) by grinding after cooling the reaction product. 1 and A-2, and amorphous polyester resins B-1, B-2, and B-3 having softening points Tm of 90 ° C. to 120 ° C. were obtained. Table 2 shows the softening point Tm, glass transition point Tg, and chloroform insoluble fraction of the obtained resins A-1, A-2, B-1, B-2, and B-3. In addition, resin A-1, A-2, B-1, B-2, and B-3 are all clear in the measurement of the DSC curve by a differential scanning calorimeter (Seiko Denshi Kogyo Co., Ltd .: DSC210). No melting peak was observed.

(C) Production of copolymer particles (Copolymer particles CCR1)
In a 3 L flask equipped with a stirrer, a condenser, a thermometer, and a nitrogen introduction tube, 1000 g of pure water and 4 g of sodium dodecyl sulfate as an emulsifier were placed, and nitrogen substitution was performed for 30 minutes. Next, 2 g of potassium peroxodisulfate (hereinafter referred to as KPS) was added and dissolved by stirring. The contents of the flask were heated to a temperature of 80 ° C. while introducing nitrogen.

  When the temperature reaches 80 ° C., an aqueous solution obtained by dissolving a mixed monomer of 300 g of styrene and 60 g of 2-ethylhexyl acrylate (hereinafter referred to as EHA) in 600 g of pure water, and 2-acrylamide-2- An aqueous solution obtained by dissolving 40 g of methylpropanesulfonic acid (hereinafter referred to as AAPS) in 600 g of pure water was separately added dropwise to the flask over 2 hours. Thereafter, the polymerization reaction was carried out for 8 hours while maintaining the temperature at 80 ° C. to obtain an emulsion solution. The obtained emulsion solution was dried with a vacuum dryer set at a temperature of 50 ° C. until the water content became 1% by weight or less, to obtain copolymer particles CCR1 satisfying the requirements of the copolymer particles in the present invention. The average particle diameter of the primary particles of the obtained copolymer particles CCR1 was 0.1 μm.

(Copolymer particles CCR2 to 10)
The copolymer particles CCR2-7 satisfying the requirements of the copolymer particles in the present invention, and the copolymer in the present invention, in the same manner as in the production of the copolymer particles CCR1, except that the raw materials having the compositions shown in Table 3 are used. Copolymer particles CCR8 to 10 that do not satisfy the requirements of the coalesced particles were obtained. Table 3 also shows the average particle diameter of the primary particles of the obtained copolymer particles.

(Copolymer particle CCR11)
A copolymer particle CCR11 not satisfying the requirements of the copolymer particle in the present invention was obtained in the same manner as in the production of the copolymer particle CCR1 except that suspension polymerization was not performed without using sodium dodecyl sulfate as an emulsifier. . The average particle diameter of the primary particles of the obtained copolymer particles CCR11 was 500 μm.

(D) Manufacturing of carrier (Carrier CR1)
An appropriate amount of each raw material was blended so as to be 20.0 mol% in terms of MnO and 80.0 mol% in terms of Fe ₂ O ₃ , water was added, and mixing was carried out while pulverizing with a wet ball mill for 10 hours. The obtained mixture was dried and held at a temperature of 950 ° C. for 4 hours, and then pulverized with a wet ball mill for 24 hours to form a slurry. The resulting slurry was granulated and dried, held in a nitrogen atmosphere at a temperature of 1300 ° C. for 6 hours, and then crushed to adjust the particle size. Thereafter, oxidation treatment was performed at a temperature of 1000 ° C. in a rotary kiln to obtain manganese-based ferrite particles as a carrier core material. The obtained ferrite particles had a weight average particle diameter of 50 μm, a saturation magnetization of 32 emu / g when a magnetic field of 3000 oersted (Oe) was applied, a residual magnetization of 3 emu / g, and a coercive force Hc of 36 Oe.

  Next, 100 g of silicone resin (Toray Dow Corning Silicone Co., Ltd .: trade name SR-2411) was weighed in terms of solid content and dissolved in 1000 mL of toluene solvent to prepare a coating resin solution. This coating resin solution was sprayed on 10 kg of the manganese-based ferrite particles prepared previously using a fluidized bed coating apparatus (weight of coating material with respect to 100 parts by weight of carrier core material: 1.0 part by weight). The coating resin solution was sprayed while adjusting the spray amount per unit time so that the time required for spraying the entire amount of the coating resin solution (hereinafter referred to as coating time) was 45 minutes. Thereafter, baking was performed at a temperature of 220 ° C. for 2 hours to obtain a carrier CR1.

Table 4 shows the physical property values of the obtained carrier CR1. As shown in Table 4, the carrier CR1 has LogR: 17.0, F1: 67.2 sec / (50 · cm ³ ), and F2: 86.8 Oe · g / cm ^3. I was satisfied.

(Carrier CR2)
A proper amount of each raw material is blended so that it is 10 mol% in terms of MnO, 39 mol% in terms of MgO, 48 mol% in terms of Fe ₂ O ₃ , 1 mol% in terms of SnO, and 2 mol% in terms of SrO, and then water is added. Mixing while grinding for 10 hours. The obtained mixture was dried and held at a temperature of 950 ° C. for 4 hours, and then pulverized with a wet ball mill for 24 hours to form a slurry. The obtained slurry was granulated and dried, held in the atmosphere at a temperature of 1260 ° C. for 6 hours, and then crushed and the particle size was adjusted to obtain ferrite particles as a carrier core material.

  Next, 250 g of silicone resin (Toray Dow Corning Silicone Co., Ltd .: trade name SR-2411) was weighed in terms of solid content and dissolved in 1000 mL of a toluene solvent to prepare a coating resin solution. Using a Henschel mixer, 10 kg of the previously produced ferrite particles were coated with the obtained coating resin solution (the weight of the coating material relative to 100 parts by weight of the carrier core material: 2.5 parts by weight). Thereafter, baking was performed at a temperature of 220 ° C. for 2 hours to obtain a carrier CR2 satisfying the requirements of the carrier in the present invention. Table 4 shows the physical property values of the obtained carrier CR2.

(Carrier CR3)
Add appropriate amounts of each raw material to 10 mol% in terms of MnO, 39 mol% in terms of MgO, 47.5 mol% in terms of Fe ₂ O ₃ , 1 mol% in terms of SnO, and 2.5 mol% in terms of SrO, and add water. The mixture was pulverized with a wet ball mill for 10 hours. The obtained mixture was dried and held at a temperature of 950 ° C. for 4 hours, and then pulverized with a wet ball mill for 24 hours to obtain a slurry. The obtained slurry was granulated and dried, held in the atmosphere at a temperature of 1260 ° C. for 6 hours, and then crushed and the particle size was adjusted to obtain ferrite particles as a carrier core material.

  Next, 250 g of acrylic modified silicone resin (manufactured by Shin-Etsu Chemical Co., Ltd .: trade name KR-9706) was weighed in terms of solid content and dissolved in 1000 mL of toluene solvent to prepare a coating resin solution. Using a Henschel mixer, 10 kg of the previously produced ferrite particles were coated with the obtained coating resin solution (the weight of the coating material relative to 100 parts by weight of the carrier core material: 2.5 parts by weight). Thereafter, baking was performed at a temperature of 220 ° C. for 2 hours to obtain a carrier CR3 satisfying the requirements of the carrier in the present invention. Table 4 shows the physical property values of the obtained carrier CR3.

(Carrier CR4)
In the production of the ferrite particles, the carrier requirement in the present invention is satisfied in the same manner as the production of the carrier CR3 except that the proportion of Fe ₂ O ₃ is 48.5 mol% and the proportion of SrO is 1.5 mol%. Carrier CR4 was produced. Table 4 shows the physical property values of the obtained carrier CR4.

(Carrier CR5)
39.7Mol% in terms of MnO, 9.9 mol% in terms of MgO, 49.6Mol% in terms _{of Fe} 2 _{O 3,} each raw material was adequate amount to be 0.8 mol% in terms of SrO, water was added, wet The mixture was pulverized with a ball mill for 10 hours. The obtained mixture was dried and held at a temperature of 950 ° C. for 4 hours, and then pulverized with a wet ball mill for 24 hours to obtain a slurry. The obtained slurry was granulated and dried, held in the atmosphere at a temperature of 1285 ° C. for 6 hours, and then crushed and the particle size was adjusted to obtain ferrite particles as a carrier core material.

  Next, 50 g of acrylic resin (Mitsubishi Rayon Co., Ltd .: trade name BR-80) was weighed in terms of solid content and dissolved in 1000 mL of a toluene solvent to prepare a coating resin solution. Using a Henschel mixer, 10 kg of the previously produced ferrite particles were coated with the obtained coating resin solution (weight of coating material relative to 100 parts by weight of carrier core material: 0.5 part by weight). Thereafter, baking was performed at a temperature of 145 ° C. for 2 hours to obtain a carrier CR5 not satisfying the requirements of the carrier in the present invention. Table 4 shows the physical property values of the obtained carrier CR5.

(Carrier CR6)
39.7Mol% in terms of MnO, 9.9 mol% in terms of MgO, 49.6Mol% in terms _{of Fe} 2 _{O 3,} each raw material was adequate amount to be 0.8 mol% in terms of SrO, water was added, wet The mixture was pulverized with a ball mill for 10 hours. The obtained mixture was dried and held at a temperature of 950 ° C. for 4 hours, and then pulverized with a wet ball mill for 24 hours to obtain a slurry. The obtained slurry was granulated and dried, held at a temperature of 1285 ° C. for 6 hours in an atmosphere having an oxygen concentration of 3%, and then crushed to adjust the particle size to obtain ferrite particles as a carrier core material.

  Next, 50 g of acrylic modified silicone resin (manufactured by Shin-Etsu Chemical Co., Ltd .: trade name KR-9706) was weighed in terms of solid content and dissolved in 1000 mL of toluene solvent to prepare a coating resin solution. Using a Henschel mixer, 10 kg of the previously produced ferrite particles were coated with the obtained coating resin solution (weight of coating material relative to 100 parts by weight of carrier core material: 0.5 part by weight). Thereafter, baking was performed at a temperature of 220 ° C. for 2 hours to obtain a carrier CR6 not satisfying the requirements of the carrier in the present invention. Table 4 shows the physical property values of the obtained carrier CR6.

(Carrier CR7)
A proper amount of each raw material is blended so as to be 8 mol% in terms of MnO, 32 mol% in terms of MgO, 49 mol% in terms of Fe ₂ O ₃ , 1 mol% in terms of SnO, and 10 mol% in terms of SrO, and then water is added. Mixing while grinding for 10 hours. The obtained mixture was dried and held at a temperature of 950 ° C. for 4 hours, and then pulverized with a wet ball mill for 24 hours to obtain a slurry. The obtained slurry was granulated and dried, held in the atmosphere at a temperature of 1285 ° C. for 6 hours, and then crushed and the particle size was adjusted to obtain ferrite particles as a carrier core material.

  Next, 50 g of acrylic resin (Mitsubishi Rayon Co., Ltd .: trade name BR-80) was weighed in terms of solid content and dissolved in 1000 mL of a toluene solvent to prepare a coating resin solution. Using a Henschel mixer, 10 kg of the previously produced ferrite particles were coated with the obtained coating resin solution (weight of coating material relative to 100 parts by weight of carrier core material: 0.5 part by weight). Thereafter, baking was performed at a temperature of 145 ° C. for 2 hours to obtain a carrier CR7 not satisfying the requirements of the carrier in the present invention. Table 4 shows the physical property values of the obtained carrier CR7.

(Carrier CR8)
Ferrite particles as a carrier core material were produced in the same manner as in the production of the carrier CR6. Next, 50 g of acrylic resin (trade name BR-80, manufactured by Mitsubishi Rayon Co., Ltd.) was weighed in terms of solid content and dissolved in 1000 mL of toluene solvent to prepare a coating resin solution. Using a Henschel mixer, 10 kg of the previously produced ferrite particles were coated with the obtained coating resin solution (weight of coating material relative to 100 parts by weight of carrier core material: 0.5 part by weight). Thereafter, baking was performed at a temperature of 145 ° C. for 2 hours to obtain a carrier CR8 not satisfying the requirements of the carrier in the present invention. Table 4 shows the physical property values of the obtained carrier CR8.

(Example)
Example I
In Example I, the influence of the binder resin on the low-temperature fixability, offset resistance, and blocking resistance of the toner was examined. Note that the carrier CR1 described above that satisfies the requirements of the carrier in the present invention was used as the carrier.

(Example 1)
In 88 parts by weight of the binder resin TB1 having the composition shown in Table 5, 6 parts by weight of carbon black (manufactured by Mitsubishi Chemical Corporation: MA100), 4 parts by weight of copolymer particles CCR1, and polypropylene wax (Sanyo Chemical Industries Co., Ltd.) 4 parts by weight made by company: Viscol 550P) and 2 parts by weight Fischer-Tropsch wax (FT wax; made by Nippon Seiki Co., Ltd .: FT7010) were uniformly mixed and then kneaded by a twin screw extruder having an internal temperature of 150 ° C. . After cooling the obtained kneaded material, the cooled material was finely pulverized with a jet mill and classified with a dispersion separator to obtain a toner TN1 having a volume average particle diameter of 9 μm. The dispersed particle diameter of the crystalline polyester resin C-1 in the obtained toner TN1 was 0.08 to 0.12 μm. In this example, the toner was prepared a plurality of times, and the average value of the major axis lengths of 50 crystalline resin particles contained in the toner was determined as the dispersed particle size each time, and the measured value obtained The dispersed particle diameter of the crystalline resin is expressed in the range of.

  The obtained toner TN1 and carrier CR1 were uniformly mixed so that the toner concentration was 6% by weight, and the developer of Example 1 satisfying the requirements of the present invention was obtained.

(Examples 2 to 8)
In the production of the toner, in the same manner as in Example 1, except that the binder resins TB2 to 8 having the compositions shown in Table 5 are used instead of the binder resin TB1, and the toners TN2 to 8 are produced. Developers of Examples 2 to 8 satisfying the requirements were produced. The dispersed particle diameter of the crystalline polyester resin in each toner was 0.08 to 0.12 μm.

Example 9
A developer of Example 9 that satisfies the requirements of the present invention was produced in the same manner as in Example 1 except that the toner TN9 was produced by using 1 part by weight of the Fischer-Tropsch wax when the toner was produced. The dispersed particle diameter of the crystalline polyester resin C-1 in the toner TN9 was 0.08 to 0.12 μm.

(Example 10)
In the production of the toner, the developer of Example 10 satisfying the requirements of the present invention was produced in the same manner as in Example 1 except that the toner TN10 was produced by using 5 parts by weight of the Fischer-Tropsch wax. The dispersed particle diameter of the crystalline polyester resin C-1 in the toner TN10 was 0.08 to 0.12 μm.

(Examples 11-14)
In the production of the toner, in the same manner as in Example 1, except that the binder resins TB9 to 12 having the compositions shown in Table 5 are used instead of the binder resin TB1, and the toners TN11 to 14 are produced. Developers of Examples 11 to 14 satisfying the requirements were produced. The dispersed particle diameter of the crystalline polyester resin in each toner was 0.08 to 0.12 μm.

(Example 15)
In the production of the toner, in the same manner as in Example 1, except that the binder resin TB10 having the composition shown in Table 5 is used instead of the binder resin TB1 and the toner TN17 is produced without using the Fischer-Tropsch wax. A developer of Example 15 was produced that satisfies the requirements of the invention. The dispersed particle diameter of the crystalline polyester resin C-4 in the toner TN17 was 0.08 to 0.12 μm.

(Example 16)
In the production of the toner, the binder resin TB10 having the composition shown in Table 5 is used instead of the binder resin TB1, and carnauba wax (melting point 85 ° C., penetration 8 or more) 2 is used instead of 2 parts by weight of the Fischer-Tropsch wax. A developer of Example 16 satisfying the requirements of the present invention was produced in the same manner as in Example 1 except that the toner TN18 was produced using parts by weight. The dispersed particle diameter of the crystalline polyester resin C-4 in the toner TN18 was 0.03 to 0.08 μm.

(Comparative Example 1)
A comparison that does not satisfy the requirements of the present invention in the same manner as in Example 1 except that the toner TN17 is prepared using the binder resin TB13 having the composition shown in Table 5 instead of the binder resin TB1. The developer of Example 1 was prepared.

(Comparative Example 2)
In the preparation of the toner, in the same manner as in Example 1 except that the binder resin TB14 having the composition shown in Table 5 is used instead of the binder resin TB1, a comparison that does not satisfy the requirements of the present invention. The developer of Example 2 was prepared.

  As described above, the developer of Examples 1 to 16 satisfying the requirements of the present invention by changing the type of binder resin and the type and blending amount of the wax in the production of the toner, and the requirements of the present invention The developers of Comparative Examples 1 and 2 that do not satisfy the above were obtained.

(Evaluation 1)
For each of the developers prepared in Examples 1 to 16 and Comparative Examples 1 and 2, the low-temperature fixability, offset resistance, and blocking resistance of the toner were evaluated as follows.

<Low temperature fixability>
By using each developer produced in Examples 1 to 16 and Comparative Examples 1 and 2, a test copying machine obtained by removing the fixing device from a commercially available copying machine (manufactured by Sharp Corporation: AR5030F), An unfixed toner image was formed on the paper. Using a test copying machine obtained by remodeling the formed unfixed toner image so that the fixing roller provided in a commercially available copying machine (manufactured by Sharp Corporation: SF8400A) can change the temperature of the fixing roller. Then, the image was fixed at a speed of 35 sheets / minute of A4 paper prescribed by JIS P0138 to form a fixed image.

Using a Gakushin type fastness tester (manufactured by Daiei Kagaku Seisakusho Co., Ltd.), the formed fixed image was rubbed back and forth three times with a sand eraser on which a 1 kg weight was placed. Before and after rubbing, the reflection density meter (manufactured by Macbeth) was used to measure the optical reflection density of the fixed image to determine the image density, and the fixing rate defined by the following formula was determined.
Fixing rate (%) = [(Image density after rubbing) / (Image density before rubbing)] × 100

  For fixed images with different levels of image density, the fixing rate was obtained, and a graph was created in which the horizontal axis represents the image density and the vertical axis plotted the fixing rate. The level of the image density of the fixed image used for the measurement was 10 levels. From the obtained graph, the minimum value of the fixing rate was obtained, and this value was defined as the minimum fixing rate at this temperature.

  The temperature of the fixing roller is sequentially increased from 155 ° C. to 240 ° C. by 5 ° C., the minimum fixing rate at each temperature is obtained, and the temperature of the fixing roller when the minimum fixing rate exceeds 70% for the first time is the minimum temperature required for fixing. That is, the minimum fixing temperature (MFR) was obtained and the low temperature fixing property was evaluated. However, when the fixing roller temperature is 155 ° C., the minimum fixing rate exceeding 70% is judged to be the minimum fixing temperature of 155 ° C. or less, and the low-temperature fixing property is very good (◎). evaluated.

Evaluation criteria for low-temperature fixability are as follows.
A: Very good. Minimum fixing temperature of 155 ° C or lower.
○: Good. The minimum fixing temperature is higher than 155 ° C and lower than 170 ° C.
Δ: Slightly poor Minimum fixing temperature of 170 ° C or higher and lower than 190 ° C.
X: Defect. Minimum fixing temperature of 190 ° C or higher.

<Offset resistance>
A commercially available copying machine in which an unfixed toner image is formed using the developers prepared in Examples 1 to 16 and Comparative Examples 1 and 2 in the same manner as the evaluation of the low-temperature fixability described above, and the fixing device is modified. Fixing was performed using (manufactured by Sharp Corporation: SF8400A). Next, a blank recording paper on which no toner image is formed is supplied to the copying machine used for fixing under the same conditions as those for fixing an unfixed toner image, and the recording paper discharged from the copying machine is supplied. The presence or absence of toner adhesion was determined by visual observation.

  This operation is repeated by gradually increasing the fixing roller temperature from 100 ° C. to 230 ° C. in 5 ° C. increments, and the temperature of the fixing roller when toner adhesion occurs for the first time is obtained as the hot offset occurrence temperature (HOF). Sex was evaluated. However, even when the temperature of the fixing roller was raised to 230 ° C., for those in which toner adhesion did not occur, it was determined that the hot offset occurrence temperature exceeded 230 ° C., and the offset resistance was very good (◎) It was evaluated.

The evaluation criteria for the offset resistance are as follows.
A: Very good. Hot offset generation temperature exceeds 230 ° C.
○: Good. Hot offset generation temperature is 210 ° C or higher and 230 ° C or lower.
Δ: Slightly poor Hot offset generation temperature is 190 ° C or higher and lower than 210 ° C.
X: Defect. Hot offset generation temperature less than 190 ° C.

<Blocking resistance>
10 g of each of the toners TN1 to TN18 produced in Examples 1 to 16 and Comparative Examples 1 and 2 was put in a glass bottle with a capacity of 100 mL and left in a thermostatic bath at a temperature of 50 ° C. for 2 days. The state of the toner after standing was visually observed to evaluate blocking resistance.

The evaluation criteria for blocking resistance are as follows.
A: Very good. No blocking is observed (toner powder form).
○: Good. Although blocking is seen, it is partial (only a part of the toner is agglomerated).
Δ: Slightly poor Soft caking condition (the toner in the container is agglomerated but fluid).
X: Defect. Hard caking state (the toner in the container is aggregated and has no fluidity).

  The above evaluation results are shown in Table 6. Table 6 also shows the dispersed particle size (μm) of the crystalline polyester resin in the toner contained in each developer. In the column of FT wax in Table 6, in Examples 1 to 16 and Comparative Example 1, the blending amount of FT wax is shown, and in Comparative Example 2, the blending amount of carnauba wax is shown.

From Examples 1 to 10, toners TN1 to TN10 produced using a binder resin containing an amorphous resin and a crystalline resin are excellent in all of low-temperature fixability, offset resistance, and blocking resistance. I understood. In Examples 11 to 16, as in Examples 1 to 8, a toner is prepared using a binder resin containing an amorphous resin and a crystalline resin. Since W _A / W _B and the ratio W _A / (W _B + W _C ) are not in a suitable range or no FT wax is used, the toner has low temperature fixability and offset resistance compared to Examples 1-8. The blocking resistance was slightly inferior.

  From Comparative Example 1, it was found that a toner prepared using a binder resin not containing a crystalline resin has good offset resistance, but low temperature fixability and blocking resistance.

  From Comparative Example 2, it was found that the toner produced using a styrene resin as the binder resin does not have good blocking resistance and also has insufficient offset resistance.

Example II
In Example II, the influence of the copolymer particles contained in the toner as a negative charge control agent on the developer characteristics was examined.

  In Example II, toners TN19 to 28 were prepared using the developer of Example 1 subjected to the evaluation in Example I and copolymer particles CCR2 to 11 instead of copolymer particles CCR1, respectively. For the developers of Examples 17 to 22 and Comparative Examples 3 to 6 produced in the same manner as in Example 1, the developer characteristics were evaluated as follows.

(Evaluation 2)
<Toner scattering>
Using the developers of Examples 1, 17 to 22 and Comparative Examples 3 to 6, an image for evaluation having a predetermined pattern was formed on the cat recording paper with a commercially available copying machine (manufactured by Sharp Corporation: AR5030F). The formed evaluation image was visually observed to evaluate the degree of toner scattering.

The evaluation criteria for the degree of toner scattering are as follows.
A: Good. No or almost no toner scattering on the evaluation image.
○: Level at which there is no problem in actual use. There is toner scattering in the evaluation image.
Δ: Level causing a problem in actual use. There is a lot of toner scattering in the evaluation image.
×: Unusable. There is a lot of toner scattering in the evaluation image.

<Image quality>
The image for evaluation used for evaluating the degree of scattering of the toner was visually observed to evaluate the image quality.

The image quality evaluation criteria are as follows.
A: Good. The gradation is good, the fine lines are clear, and the resolution is very good.
○: Level at which there is no problem in actual use. There is no problem with both gradation and fine lines (resolution).
Δ: Level causing a problem in actual use. The gradation is poor and the fine lines are not clear.
×: Unusable. The gradation is very bad and the thin lines are broken.

<Durability>
Using the developers of Examples 1 and 7 to 22 and Comparative Examples 3 to 6, a commercially available copier (manufactured by Sharp Corporation: AR5030F) formed an image for evaluation with a predetermined pattern on 100,000 sheets of cat recording paper. Then, a printing durability test was conducted. The degree of deterioration of the image quality of the evaluation image during the printing durability test was judged by visual observation, and the durability of the developer was evaluated.

The evaluation criteria for durability are as follows.
A: Excellent. No deterioration in image quality between the first and 100,000th sheet.
○: Good. There is no image degradation from the 1st sheet to the 50,000th sheet, and there is image degradation between the 50,000th sheet and the 100,000th sheet.
Δ: Slightly poor There is image degradation between the first and 50,000th sheet.
X: Defect. There is significant image degradation between the 1st and 5000th sheets.
The above evaluation results are shown in Table 7.

  From Table 7, it is obtained by polymerizing a monomer containing 99 to 80% by weight of a radical polymerizable monomer and 1 to 20% by weight of a sulfonic acid monomer as a negative charge control agent for the toner. In the developers of Examples 1 and 17 to 22 using copolymer particles CCR1 to CCR7 having an average particle diameter of 0.01 μm or more and 2 μm or less, toner scattering is suppressed and a high quality image can be obtained. I understood. It was also found that the developers of Examples 1 and 17 to 22 were excellent in durability.

  On the other hand, as the negative charge control agent of the toner, the copolymer particles CCR8 to 10 in which the ratio of the sulfonic acid monomer is out of the above range, or the average particle diameter of the primary particles is out of the above range. In the developers of Comparative Examples 3 to 6 using the polymer particles CCR11, although the same developer as in Examples 1 and 17 to 22 is used as the carrier and toner binder resin, the toner scattering Occurred frequently, the image quality was poor, and the durability was poor.

Example III
In Example III, the influence of the carrier on the developer characteristics was examined.

  In Example III, Example 23 was produced in the same manner as Example 1 except that the developer of Example 1 subjected to the evaluation in Example I and the carriers CR2 to 8 were used in place of the carrier CR1. With respect to ˜25 and the developers of Comparative Examples 7 to 10, toner scattering degree, image quality, and durability were evaluated in the same manner as in Example II. Further, the degree of bias of the developer and the degree of adhesion of the carrier were evaluated as follows.

<Developer bias>
Using the developers of Examples 1, 23 to 25 and Comparative Examples 7 to 10, an image for evaluation having a predetermined pattern was formed on the cat recording paper by a commercially available copying machine (manufactured by Sharp Corporation: AR5030F). The formed evaluation image was visually judged for the presence or absence of uneven image density, and the deviation degree of the developer in the developing device was evaluated.

Evaluation criteria for the degree of bias of the developer are as follows.
A: No developer bias. There is no uneven density in the evaluation image.
○: Almost no deviation of developer. The image for evaluation has uneven density that can be ignored.
Δ: Deviation of developer. There is uneven density in the evaluation image.
X: Deviation of developer is large. The image for evaluation has fairly clear density unevenness.

<Carrier adhesion>
Using the developers of Examples 1, 23 to 25 and Comparative Examples 7 to 10, an evaluation image having a predetermined pattern was formed on 10 sheets of recording paper using a commercially available copying machine (manufactured by Sharp Corporation: AR5030F). The formed image for evaluation was visually observed, the number of white spots corresponding to the adhesion of the carrier was determined, and the degree of adhesion of the carrier to the recording paper was evaluated.

The evaluation criteria for the degree of carrier adhesion are as follows.
A: No carrier adhesion. No vitiligo in 10 images for evaluation.
○: Almost no carrier adhered. 1 to 5 vitiligo in 10 images for evaluation.
Δ: Carrier adhered. 6-10 vitiligo in 10 images for evaluation.
X: Many carrier adhesions. 11 or more white spots in 10 images for evaluation.
The above evaluation results are shown in Table 8.

From Table 8, Example 1 using carriers CR1 to 4 in which LogR is in the range of 12 to 25, F1 is in the range of 63 to 75 sec / (50 · cm ³ ), and F2 is in the range of ^{30 to} 100 Oe · g / cm ^3. In addition, it was found that the developer of Nos. 23 to 25 can suppress toner scattering, developer bias, and carrier adhesion, and obtain a high-quality image. It was also found that the developers of Examples 1 and 23 to 25 were excellent in durability.

  On the other hand, in the developers of Comparative Examples 7 to 10 in which at least one of Log R, F1, and F2 is out of the above range as the carrier, the developers of Comparative Examples 7 to 10 are developed in Examples 1 and 23 to 25. Despite using the same toner as the agent, toner scattering, developer bias and carrier adhesion occurred, resulting in poor image quality and poor durability.

From the results of Examples I to III above, a binder resin containing an amorphous resin and a crystalline resin, 99 to 80% by weight of a radical polymerizable monomer, and 1 to 20% by weight of a sulfonic acid monomer LogR is 12 or more and 25 or less with respect to a toner containing copolymer particles obtained by polymerizing a monomer and containing copolymer particles having an average particle diameter of 0.01 μm or more and 2 μm or less, and F1 Is combined with a carrier having a F2 of 30 Oe · g / cm ³ or more and 100 Oe · g / cm ³ or less by combining a carrier having an A of 63 sec / (50 · cm ³ ) or more and 75 sec / (50 · cm ³ ) or less. It was found that a developer capable of realizing a high-quality image without toner scattering and without fogging can be obtained.

It is a perspective view which shows typically the structure of the cell 11 for resistance measurement used for the measurement of the electrical resistivity R of a carrier.

Explanation of symbols

11 Resistance measurement cell 11
12a, 12b electrode 13 carrier

Claims (20)

A developer comprising a toner and a carrier,
The toner is
(A) a binder resin including an amorphous resin and a crystalline resin;
(B) Copolymer particles obtained by polymerizing a monomer containing 99 to 80% by weight of a radical polymerizable monomer and 1 to 20% by weight of a sulfonic acid monomer, Copolymer particles having an average particle diameter of 0.01 μm or more and 2 μm or less,
The carrier is
The electrical resistivity R (Ω · cm) is 12 to 25 in common logarithm (LogR),
The first fluidity index F1 represented by the following formula (1) is 63 sec / (50 · cm ³ ) or more and 75 sec / (50 · cm ³ ) or less,
A developer, wherein the second fluidity index F2 represented by the following formula (2) is 30 Oe · g / cm ³ or more and 100 Oe · g / cm ³ or less.
F1 = AD × FR (1)
F2 = AD × Hc (2)
Where AD: apparent density (g / cm ³ ),
FR: fluidity (sec / 50 g),
Hc: Coercive force (Oe) when a magnetic field of 3000 Oe is applied   The developer according to claim 1, wherein the crystalline resin has a softening point of 80 ° C. or higher and 150 ° C. or lower. The amorphous resin includes a resin (resin A) having a softening point of 120 ° C. or higher and 170 ° C. or lower and a resin (resin B) having a softening point of 90 ° C. or higher and 120 ° C. or lower,
The developer according to claim 1, wherein the crystalline resin has a melting point of 60 ° C. or higher and 140 ° C. or lower. Developer of claim 3, wherein the ratio of the weight _{W B} of the weight _{W A} and the resin B _(W A / _{W B)} is 100/70 or 100/10 or less of the resin A. The ratio (W _A / (W _B + W _C )) of the weight W _{A of the} resin A and the sum (W _B + W _C ) of the weight W _B of the resin _B and the weight W _C of the crystalline resin is: 100/110 or more and 100/20 or less,
And the ratio of the weight _{W C} of the crystalline resin and the weight _{W B} of the resin B _(W B / W _C) is according to claim 3 or 4, wherein the at 1/1 or more 4/1 or less Developer.   The developer according to claim 1, wherein the amorphous resin and / or the crystalline resin is a polyester resin.   The crystalline resin is a crystalline polyester resin obtained by condensation polymerization of a monomer containing a diaryl compound in an amount of 0.1 mol% to 20 mol%. The developer according to any one of the above.   The developer according to claim 7, wherein the diaryl compound is a diol compound having a bisphenol A skeleton.   The crystalline polyester resin is obtained by polycondensation of a monomer other than a diaryl compound by 50% or more and then adding a diaryl compound to the reaction system and further polycondensation. The developer according to 7 or 8.   The developer according to any one of claims 7 to 9, wherein the amorphous resin is obtained by condensation polymerization of a monomer containing 40 mol% or more of a diaryl compound. .   11. The developer according to claim 1, wherein a dispersed particle diameter of the crystalline resin in the toner is 0.05 μm or more and 0.20 μm or less. The toner further contains a wax,
The ratio of the weight _{W C} of the crystalline resin and the weight _{W W} of the wax _(W C / _{W W)} is of the claims 1 to 11, characterized in that at 1/1 or more 4/1 or less The developer according to any one of the above. The radical polymerizable monomer is a styrene monomer and / or an acrylic monomer,
The developer according to claim 1, wherein the sulfonic acid monomer is 2-acrylamido-2-methylpropanesulfonic acid.   The copolymer particles are obtained by emulsion polymerization of a monomer containing a radical polymerizable monomer and a sulfonic acid monomer. The developer according to any one of the above.   The developer according to claim 14, wherein the copolymer particles are obtained by separately dropping a radical polymerizable monomer and a sulfonic acid monomer into a polymerization system.   The developer according to claim 1, wherein the carrier has a weight average particle diameter Dw of 30 μm or more and 120 μm or less.   The developer according to any one of claims 1 to 16, wherein the carrier has a coercive force Hc of 12 Oe or more and 60 Oe or less when a magnetic field of 3000 Oe is applied.   18. The developer according to claim 1, wherein the carrier has a saturation magnetization of 20 emu / g or more and 45 emu / g or less when a magnetic field of 3000 Oe is applied. The carrier is
Including a carrier core and a coating layer covering the carrier core;
The weight of the coating layer is 0.8 parts by weight or more and 15 parts by weight or less with respect to 100 parts by weight of the carrier core material, according to any one of claims 1 to 18. Developer. The carrier is
Including a carrier core and a coating layer covering the carrier core;
The developer according to claim 1, wherein the carrier core material is ferrite.

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